Prey

and

Non-prey

Arthropods

Sharing

a

Host

Plant

Effects

on

Induced

Volatile

Emission

and

Predator

Attraction

It

is

well

established

that

plants

infested

with

a

single

herbivore

species

can

attract

specific

natural

enemies

through

the

emission

of

herbivore-induced

volatiles

However

it

is

less

clear

what

happens

when

plants

are

simultaneously

attacked

by

more

than

one

species

We

analyzed

volatile

emissions

of

lima

bean

and

cucumber

plants

upon

multi-species

herbivory

by

spider

mites

-LRB-

Tetranychus

urticae

-RRB-

and

caterpillars

-LRB-

Spodoptera

exigua

-RRB-

in

comparison

to

single-species

herbivory

Upon

herbivory

by

single

or

multiple

species

lima

bean

and

cucumber

plants

emitted

volatile

blends

that

comprised

mostly

the

same

compounds

To

detect

additive

synergistic

or

antagonistic

effects

we

compared

the

multi-species

herbivory

volatile

blend

with

the

sum

of

the

volatile

blends

induced

by

each

of

the

herbivore

species

feeding

alone

In

lima

bean

the

majority

of

compounds

were

more

strongly

induced

by

multi-species

herbivory

than

expected

based

on

the

sum

of

volatile

emissions

by

each

of

the

herbivores

separately

potentially

caused

by

synergistic

effects

In

contrast

in

cucumber

two

compounds

were

suppressed

by

multi-species

herbivory

suggesting

the

potential

for

antagonistic

effects

We

also

studied

the

behavioral

responses

of

the

predatory

mite

Phytoseiulus

persimilis

a

specialized

natural

enemy

of

spider

mites

Olfactometer

experiments

showed

that

P.

persimilis

preferred

volatiles

induced

by

multi-species

herbivory

to

volatiles

induced

by

S.

exigua

alone

or

by

prey

mites

alone

We

conclude

that

both

lima

bean

and

cucumber

plants

effectively

attract

predatory

mites

upon

multi-species

herbivory

but

the

underlying

mechanisms

appear

different

between

these

species

Introduction

Plants

can

employ

arthropod

natural

enemies

and

defend

themselves

against

herbivorous

insects

and

mites

Such

arthropod

natural

enemies

can

have

an

impact

on

local

herbivore

populations

and

thereby

also

on

plant

fitness

-LRB-

Sabelis

and

van

der

Meer

Dicke

and

Sabelis

Pels

and

Sabelis

van

Loon

et

al.

Fritzsche

Hoballah

and

Turlings

Kessler

and

Baldwin

-RRB-

Plants

can

promote

the

effectiveness

of

natural

enemies

by

providing

alternative

food

shelter

or

volatiles

-LRB-

Price

et

al.

Dicke

and

Sabelis

-RRB-

The

emission

of

herbivore-induced

plant

volatiles

-LRB-

HIPV

-RRB-

has

been

demonstrated

in

several

families

-LRB-

e.g.

Dicke

et

al.

Turlings

et

al.

van

den

Boom

et

al.

van

Poecke

and

Dicke

-RRB-

Many

parasitoid

wasps

predatory

mites

and

predatory

insects

use

HIPV

to

locate

their

prey

or

hosts

-LRB-

reviewed

in

Dicke

Dicke

and

Vet

Sabelis

et

al.

-RRB-

HIPV

are

thus

thought

to

have

an

important

influence

on

the

interactions

between

plants

herbivores

and

natural

enemies

in

food

webs

-LRB-

Turlings

et

al.

Dicke

and

Vet

-RRB-

To

date

studies

on

the

production

of

HIPV

by

plants

and

the

responses

of

natural

enemies

to

these

have

been

carried

out

mostly

for

systems

with

one

species

of

plant

herbivore

and

natural

enemy

Yet

in

the

field

most

plants

are

likely

to

be

attacked

by

several

herbivore

species

or

by

herbivores

and

pathogens

at

the

same

time

It

is

difficult

to

predict

whether

or

not

changes

in

HIPV

blends

upon

multi-species

herbivory

affect

attraction

of

natural

enemies

and

in

what

direction

Several

studies

have

attempted

to

fill

this

gap

by

analyzing

the

chemical

composition

of

volatile

blends

upon

multi-species

infestation

of

plants

-LRB-

Shiojiri

et

al.

Cardoza

et

al.

Rodriguez-Saona

et

al.

Rostás

et

al.

Moayeri

et

al.

Rasmann

and

Turlings

Soler

et

al.

-RRB-

For

instance

Shiojiri

et

al.

-LRB-

-RRB-

showed

that

the

parasitoid

wasp

Cotesia

plutellae

prefers

the

HIPV

blend

induced

by

its

host

Plutella

xylostella

to

the

blend

induced

by

multi-species

herbivory

by

its

host

and

the

non-host

caterpillar

Pieris

rapae

although

volatile

blends

are

similar

-LRB-

Shiojiri

et

al.

-RRB-

Cotesia

glomerata

on

the

other

hand

prefers

HIPV

blends

induced

by

its

host

P.

rapae

and

non-host

caterpillars

to

blends

induced

by

one

caterpillar

species

feeding

alone

-LRB-

Shiojiri

et

al.

Vos

et

al.

-RRB-

Cotesia

marginiventris

and

Microplitis

rufiventris

do

not

discriminate

between

the

multi-species-induced

HIPV

blend

of

plants

infested

with

their

host

-LRB-

beet

armyworm

caterpillars

-RRB-

and

a

plant

pathogen

or

plants

infested

with

their

host

alone

although

the

pathogen

significantly

suppresses

volatile

induction

-LRB-

Rostás

et

al.

-RRB-

Similarly

C.

glomerata

does

not

discriminate

between

mustard

plants

infested

with

a

root

herbivore

and

its

host

or

plants

infested

with

its

host

alone

-LRB-

Soler

et

al.

-RRB-

The

parasitoid

C.

marginiventris

and

the

entomopathogenic

nematode

Heterorhabditis

megidis

exhibited

a

reduced

attraction

to

volatiles

from

maize

plants

that

were

infested

by

a

non-host

in

addition

to

their

host

although

the

non-host

was

feeding

on

different

tissues

from

the

host

i.e.

leaves

vs.

roots

-LRB-

Rasmann

and

Turlings

-RRB-

In

this

study

we

investigated

the

effects

of

multi-species

herbivory

by

spider

mites

-LRB-

Tetranychus

urticae

-RRB-

and

beet

armyworm

caterpillars

-LRB-

Spodoptera

exigua

-RRB-

on

volatile

emissions

by

two

different

plant

species

lima

bean

-LRB-

Phaseolus

lunatus

-RRB-

and

cucumber

-LRB-

Cucumis

sativus

-RRB-

and

evaluated

the

responses

of

Phytoseiulus

persimilis

a

specialist

natural

enemy

of

spider

mites

Both

herbivore

species

are

known

to

induce

volatile

emission

in

several

plant

species

and

remarkable

differences

in

HIPV

blend

composition

have

been

found

in

lima

bean

infested

by

either

of

these

herbivores

-LRB-

e.g.

Ozawa

et

al.

Schmelz

et

al.

de

Boer

et

al.

-RRB-

We

statistically

compared

volatile

emission

by

multi-species-infested

plants

with

the

sum

of

volatile

emissions

of

plants

infested

with

either

herbivore

species

alone

to

evaluate

the

presence

of

potentially

antagonistic

or

synergistic

effects

among

signal

transduction

pathways

-LRB-

e.g.

Engelberth

et

al.

-RRB-

Plant

responses

to

multi-species

herbivory

may

depend

on

feeding

modes

of

the

herbivore

species

involved

-LRB-

Walling

-RRB-

but

whether

or

not

plant

species

differ

in

these

responses

is

unknown

Therefore

we

compared

two

plant

species

in

their

relative

responses

to

multi-species

vs.

single-species

herbivory

by

using

the

same

two

herbivore

species

to

attack

both

plant

species

We

also

studied

the

olfactory

responses

of

predatory

mites

-LRB-

P.

persimilis

-RRB-

In

nature

plants

are

commonly

attacked

by

more

than

one

herbivore

Knowledge

on

natural

enemy

responses

to

volatile

blends

induced

by

multi-species

vs.

single-species

herbivory

is

essential

to

understand

whether

differences

in

volatile

composition

are

relevant

in

an

ecological

context

Methods

and

Materials

Plants

Herbivores

and

Predators

Lima

bean

plants

-LRB-

Phaseolus

lunatus

L.

cv

Sieva

-RRB-

and

cucumber

plants

-LRB-

C.

sativus

L.

cv

Lange

Groene

Giganten

-RRB-

were

grown

in

a

greenhouse

at

°C

R.H.

and

hr

of

light

Bean

plants

were

used

when

their

primary

leaves

had

unfolded

-LRB-

and

were

about

cm

wide

-RRB-

which

was

d

after

sowing

Cucumber

plants

were

used

when

their

first

two

leaves

were

about

cm

wide

which

was

d

after

sowing.Two-spotted

spider

mites

Tetranychus

urticae

Koch

-LRB-

Acari

Tetranychidae

-RRB-

were

reared

on

lima

bean

plants

in

a

greenhouse

under

the

same

conditions

as

uninfested

plants

Eggs

of

the

beet

armyworm

Spodoptera

exigua

Hübner

-LRB-

Lepidoptera

Noctuidae

-RRB-

were

obtained

from

a

colony

reared

on

artificial

diet

in

the

laboratory

of

Virology

Wageningen

University

The

Netherlands

-LRB-

Smits

et

al.

-RRB-

Two

to

three

batches

of

eggs

were

placed

in

a

Petri

dish

together

with

a

lima

bean

or

cucumber

leaf

in

a

growth

chamber

at

°C

Larvae

were

used

in

experiments

within

hr

of

hatching.A

colony

of

predatory

mites

Phytoseiulus

persimilis

Athias-Henriot

-LRB-

Acari

Phytoseiidae

-RRB-

was

kept

on

spider

mite-infested

lima

bean

leaves

in

a

growth

chamber

at

°C

R.H.

and

continuous

light

To

obtain

females

of

the

same

age

for

olfactometer

experiments

gravid

females

were

allowed

to

oviposit

on

a

spider

mite-infested

bean

leaf

for

d

The

female

offspring

were

used

in

experiments

d

after

initiation

of

the

colonies

i.e.

d

after

their

final

molt

Before

the

experiments

females

were

kept

individually

in

microcentrifuge

tubes

with

a

small

droplet

of

water

for

hr

at

°C

Plant

Treatments

Treatments

were

applied

to

the

two

oldest

leaves

of

lima

bean

or

cucumber

plants

d

before

an

experiment

Plants

were

incubated

in

plastic

cages

in

a

climate-controlled

chamber

at

°C

R.H.

and

each

treatment

in

a

separate

cage

We

used

the

following

four

treatments

T.

urticae

Adult

female

spider

mites

were

transferred

to

experimental

plants

Twenty

mites

per

leaf

were

used

on

lima

bean

and

mites

per

leaf

were

used

on

cucumber

because

the

same

number

of

spider

mites

leads

to

lower

attraction

of

P.

persimilis

to

cucumber

than

to

lima

bean

plants

-LRB-

Dicke

et

al.

-RRB-

S.

exigua

Newly

hatched

S.

exigua

larvae

were

placed

in

clip

cages

to

keep

caterpillars

on

the

leaves

-LRB-

clip

cages

were

made

of

two

plastic

cylinders

cm

diam.

and

a

hairpin

the

upper

side

was

covered

with

gauze

and

the

underside

with

Parafilm

-RRB-

Two

larvae

in

one

clip

cage

were

used

per

leaf

Clip

cages

were

moved

daily

to

a

new

position

on

the

same

leaf

and

any

missing

larvae

were

replaced

The

clip

cages

were

supported

by

sticks

to

prevent

the

leaves

from

bending

and

incurring

damage

due

to

the

weight

of

the

cages.Multi-species

herbivory

Two

newly

hatched

S.

exigua

larvae

in

a

clip

cage

and

-LRB-

lima

bean

-RRB-

or

-LRB-

cucumber

-RRB-

T.

urticae

females

were

placed

on

each

leaf.Uninfested

Plants

without

herbivores

were

treated

in

the

same

way

as

plants

of

the

other

treatments

This

treatment

was

only

used

for

volatile

collections

of

cucumber

We

did

not

analyze

volatile

emission

from

uninfested

lima

bean

plants

because

it

is

documented

that

they

emit

low

amounts

of

volatiles

-LRB-

e.g.

de

Boer

et

al.

-RRB-

When

clip

cages

were

used

to

keep

caterpillars

in

place

T.

urticae-infested

or

uninfested

plants

were

treated

in

the

same

way

with

empty

clip

cages

to

avoid

any

cage

effects

Volatile

Collections

and

Analyses

Just

before

volatile

collections

plants

were

cut

above

the

soil

line

Stems

of

individual

plants

were

wrapped

in

moist

cotton

and

aluminum

foil

to

prevent

them

from

wilting

during

volatile

collection

which

lasted

at

most

hr

All

clip

cages

caterpillars

and

their

products

were

removed

Five

plants

of

one

treatment

were

transferred

to

a

glass

vessel

A

viton

O-ring

and

a

metal

clamp

were

used

to

attach

the

glass

lid

to

the

vessel

to

make

it

airtight

Purified

air

-LRB-

filtered

through

silica

a

molecular

sieve

activated

charcoal

and

mg

Tenax

-RRB-

was

split

into

two

air

streams

of

about

ml/min

each

and

led

into

the

vessels

through

teflon

tubing

Volatiles

from

two

treatments

were

collected

simultaneously

in

parallel

The

system

was

purged

for

min

before

attaching

a

collection

tube

with

Tenax

-LRB-

mg

for

bean

samples

mg

for

cucumber

samples

-RRB-

to

the

air

outlet

in

the

lid

of

the

vessel

Bean

volatiles

were

collected

for

min

cucumber

volatiles

were

collected

for

hr

For

lima

bean

volatile

collection

was

repeated

four

times

for

each

treatment

except

for

uninfested

from

which

volatiles

were

not

sampled

For

cucumber

volatile

collections

were

replicated

seven

times

for

the

uninfested

six

times

for

T.

urticae

and

five

times

for

S.

exigua

and

multi-species

herbivory

each

One

sample

of

the

T.

urticae

and

one

of

the

S.

exigua

treatments

of

cucumber

were

lost

during

the

analysis.Volatiles

from

lima

bean

and

cucumber

were

analyzed

on

two

different

gas

chromatography-mass

spectrometry

-LRB-

GC-MS

-RRB-

systems

Lima

bean

Volatiles

were

released

from

Tenax

traps

with

a

thermodesorption

cold

trap

setup

-LRB-

Chrompack

Middelburg

The

Netherlands

-RRB-

by

heating

at

°C

for

min

with

a

He-flow

of

ml/min

Desorbed

compounds

were

collected

in

the

cold

trap

at

°C

Volatiles

were

injected

in

splitless

mode

into

the

column

-LRB-

m

mm

ID

μm

film

thickness

-RRB-

by

heating

the

cold

trap

to

°C

After

an

initial

column

temperature

of

°C

for

min

the

temperature

was

raised

to

°C

at

°C

min

The

column

was

directly

coupled

to

the

ion

source

of

a

Finnigan

MAT

mass

spectrometer

which

was

operating

in

the

electron

impact

-LRB-

EI

-RRB-

ionization

mode

with

scanning

from

mass

to

at

scan/sec

Compounds

were

identified

by

comparison

of

mass

spectra

with

those

in

the

NIST

library

and

in

the

Wageningen

Mass

Spectral

Database

of

Natural

Products

and

by

checking

the

retention

indices

Cucumber

Volatiles

were

released

from

Tenax

traps

with

a

thermodesorption

cold

trap

setup

-LRB-

Markes

UK

-RRB-

by

heating

at

°C

for

min

with

a

He-flow

of

ml/min

The

desorbed

volatiles

were

collected

in

the

cold

trap

at

°C

Volatiles

were

injected

in

splitless

mode

into

the

column

-LRB-

Restec

m

mm

ID

μm

film

thickness

-RRB-

by

heating

of

the

coldtrap

to

°C

After

an

initial

column

temperature

of

°C

for

min

the

temperature

was

raised

to

°C

at

°C

min

then

to

°C

at

°C

min

and

subsequently

to

°C

at

°C

min

The

column

was

directly

coupled

to

the

ion

source

of

a

Finnigan

quadrupole

mass

spectrometer

which

was

operated

in

the

EI

ionization

mode

and

scanned

from

mass

to

at

three

scans/sec

Compounds

were

identified

by

comparison

of

mass

spectra

with

those

in

the

NIST

and

Wiley

edition

spectral

libraries

and

by

checking

the

retention

indices

Analyses

Not

all

compounds

were

detected

in

every

replicate

of

every

treatment

We

therefore

added

one

peak

area

unit

to

all

measurements

for

lima

bean

and

units

to

all

measurements

for

cucumber

These

were

the

lowest

recorded

non-zero

values

for

bean

and

cucumber

respectively

This

enabled

us

to

plot

volatile

emission

on

a

log

scale

-LRB-

Figs.

and

-RRB-

and

to

determine

ratios

among

treatments

-LRB-

see

below

-RRB-

Fig.

of

multi-species

herbivory

on

volatile

emission

by

lima

bean

plants

-LRB-

a

-RRB-

Volatile

emission

-LRB-

mean

SE

peak

area

units

-RRB-

upon

single

herbivory

by

Tetranychus

urticae

-LRB-

mites

per

leaf

-RRB-

-LRB-

open

bars

-RRB-

single

herbivory

by

Spodoptera

exigua

-LRB-

two

larvae

per

leaf

-RRB-

-LRB-

filled

bars

-RRB-

or

multi-species

herbivory

-LRB-

hatched

bars

-RRB-

Asterisks

indicate

compounds

that

were

significantly

affected

by

herbivore

treatment

-LRB-

P

Kruskal

Wallis

tests

-RRB-

-LRB-

b

-RRB-

Ratio

of

emission

rates

upon

multi-species

herbivory

to

the

sum

per

volatile

emitted

by

the

two

single

herbivore

treatments

-LRB-

see

Methods

and

Materials

for

detailed

explanation

-RRB-

Symbols

indicate

mean

ratio

and

error

bars

indicate

upper

and

lower

confidence

limits

Asterisks

indicate

compounds

that

were

significantly

more

strongly

induced

by

multi-species

herbivory

than

by

the

sum

of

T.

urticae

and

S.

exigua

-LRB-

lower

confidence

limit

larger

than

-RRB-

N

for

all

treatments

Compound

numbers

-LRB-

-RRB-

-LRB-

Z

-RRB-

-LRB-

-RRB-

methyl

salicylate

-LRB-

-RRB-

-LRB-

E

-RRB-

β-ocimene

-LRB-

-RRB-

-LRB-

E

-RRB-

-LRB-

-RRB-

-LRB-

E

-RRB-

-4,8,12-trimethyl-1,3,7,11-tridecatetraene

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

Z

-RRB-

acetate

-LRB-

-RRB-

oxime

-LRB-

-RRB-

oxime

-LRB-

-RRB-

linalool

-LRB-

-RRB-

-LRB-

-RRB-

hexyl

acetate

-LRB-

-RRB-

limonene

-LRB-

-RRB-

β-caryophyllene

-LRB-

-RRB-

nonanal

-LRB-

-RRB-

indole

-LRB-

-RRB-

-LRB-

E

-RRB-

acetate

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

nitrile

-LRB-

-RRB-

-LRB-

Z

-RRB-

β-ocimene

-LRB-

-RRB-

rose

furan

-LRB-

-RRB-

unknown

-LRB-

-RRB-

nitrile

-LRB-

-RRB-

unknown

-LRB-

-RRB-

unknown

-LRB-

-RRB-

oximeFig

of

multi-species

herbivory

on

volatile

emission

by

cucumber

plants

-LRB-

a

-RRB-

Volatile

emission

-LRB-

mean

SE

peak

area

units

-RRB-

upon

single

herbivory

by

Tetranychus

urticae

-LRB-

mites

per

leaf

N

open

bars

-RRB-

single

herbivory

by

Spodoptera

exigua

-LRB-

larvae

per

leaf

N

filled

bars

-RRB-

or

multi-species

herbivory

-LRB-

N

hatched

bars

-RRB-

Asterisks

indicate

compounds

that

are

significantly

affected

by

herbivore

treatment

-LRB-

P

Kruskal

Wallis

tests

-RRB-

-LRB-

b

-RRB-

Ratio

of

emission

rates

upon

multi-species

herbivory

to

the

sum

per

volatile

emitted

by

the

two

single

herbivore

treatments

-LRB-

see

Methods

and

Materials

and

for

detailed

explanation

-RRB-

Symbols

indicate

mean

ratio

and

error

bars

indicate

upper

and

lower

confidence

limits

Asterisks

indicate

compounds

that

were

significantly

less

induced

by

multi-species

herbivory

than

by

the

sum

of

T.

urticae

and

S.

exigua

-LRB-

upper

confidence

limit

smaller

than

-RRB-

-LRB-

N

-RRB-

Compound

numbers

-LRB-

-RRB-

-LRB-

E

-RRB-

-LRB-

Z

-RRB-

-LRB-

-RRB-

-LRB-

Z

-RRB-

acetate

-LRB-

-RRB-

indole

-LRB-

-RRB-

-LRB-

E

E

-RRB-

α-farnesene

-LRB-

-RRB-

butyl

aldoxime

-LRB-

-RRB-

oxime

-LRB-

-RRB-

-LRB-

E

-RRB-

-LRB-

-RRB-

-LRB-

E

-RRB-

-LRB-

-RRB-

-LRB-

E

-RRB-

β-ocimene

Note

that

peak

area

units

in

Fig.

can

not

be

compared

with

Fig.

because

measurements

were

done

on

a

different

GC-MS

systemFor

cucumber

we

first

determined

which

volatile

compounds

were

induced

by

herbivory

by

using

Kruskal

Wallis

tests

per

compound

Variation

in

volatile

emission

levels

of

uninfested

plants

was

low

indicating

that

other

types

of

inducing

factors

-LRB-

e.g.

general

stress

-RRB-

were

absent

or

had

only

minor

effects

Only

herbivore-induced

volatiles

were

used

in

subsequent

analyses

We

assumed

that

all

compounds

emitted

by

infested

lima

bean

plants

were

induced

by

herbivores

based

on

previous

measurements

of

volatile

emissions

by

uninfested

lima

bean

plants

-LRB-

e.g.

de

Boer

et

al.

-RRB-

Per

plant

species

we

then

used

Kruskal

Wallis

tests

to

analyze

which

compounds

were

differentially

induced

by

the

three

herbivore

treatments

-LRB-

T.

urticae

S.

exigua

or

multi-species

herbivory

-RRB-

-LRB-

α

-RRB-

Note

that

we

did

not

statistically

compare

absolute

levels

of

volatile

emission

across

plant

species

because

volatiles

were

collected

for

different

periods

of

time

and

analyses

were

run

on

two

different

GC-MS

systems.We

also

tested

whether

the

effect

on

HIPV

of

multi-species

herbivory

was

the

same

as

the

combined

effect

of

the

two

herbivores

feeding

alone

i.e.

T.

urticae

S.

exigua

Per

replicate

the

amount

of

each

volatile

compound

of

the

multi-species

herbivory

treatment

was

divided

by

the

sum

of

the

amounts

emitted

by

T.

urticae

and

S.

exigua

The

ratios

were

log-transformed

before

taking

their

averages

An

average

ratio

of

means

the

effect

of

multi-species

herbivory

and

the

sum

of

T.

urticae

and

S.

exigua

is

equal

We

concluded

that

a

compound

was

significantly

more

strongly

induced

by

multi-species

herbivory

than

by

the

sum

of

T.

urticae

and

S.

exigua

if

the

lower

confidence

limit

was

larger

than

Similarly

we

concluded

a

significantly

weaker

effect

of

multi-species

herbivory

if

the

upper

confidence

limit

was

smaller

than

-LRB-

see

Figs.

and

-RRB-

We

also

used

a

χ2

test

to

test

whether

the

number

of

compounds

with

a

ratio

and

a

ratio

differed

from

a

distribution

A

distribution

would

be

expected

if

the

effect

of

multi-species

herbivory

and

the

sum

of

T.

urticae

and

S.

exigua

is

equal

One

replicate

of

the

T.

urticae

treatment

in

cucumber

was

excluded

from

this

analysis

because

we

had

no

corresponding

replicates

of

the

S.

exigua

and

multi-species

herbivory

treatments

Note

that

these

tests

reflect

volatile

responses

to

multi-species

herbivory

relative

to

responses

to

single-species

herbivory

This

allows

us

to

compare

these

data

between

lima

bean

and

cucumber

because

the

data

no

longer

depend

on

the

absolute

levels

of

volatiles

detected

by

the

different

GC-MS

systems

Y-tube

Olfactometer

Experiments

A

closed

system

Y-tube

olfactometer

setup

was

used

to

test

the

responses

of

predatory

mites

to

volatiles

induced

by

multi-species

herbivory

-LRB-

Takabayashi

and

Dicke

de

Boer

et

al.

-RRB-

Odor

sources

consisted

of

four

leaves

of

the

same

treatment

that

were

cut

from

the

plant

just

before

an

experiment

the

petioles

were

wrapped

in

wet

cotton

wool

and

aluminum

foil

Individual

female

predators

were

observed

for

a

maximum

of

min

A

choice

was

recorded

when

the

finish

line

halfway

one

of

the

olfactometer

arms

was

reached

within

this

period

Otherwise

it

was

recorded

as

no-choice

Sixteen

to

predators

were

tested

per

experimental

day

and

each

experiment

was

repeated

on

different

days

Per

replicate

new

groups

of

predatory

mites

and

new

sets

of

leaves

were

used

We

tested

the

responses

of

predatory

mites

to

volatiles

from

bean

or

cucumber

plants

of

the

multi-species

herbivory

treatment

vs.

volatiles

from

plants

of

the

T.

urticae

or

S.

exigua

treatments.The

choices

of

predatory

mites

between

two

odor

sources

in

the

Y-tube

olfactometer

were

analyzed

with

two-sided

binomial

tests

to

investigate

whether

the

distribution

of

the

predators

differed

from

Predators

that

did

not

make

a

choice

were

excluded

from

statistical

analyses

Results

Volatile

Emission

by

Lima

Bean

Plants

The

main

compounds

emitted

by

T.

urticae-infested

bean

plants

were

methyl

salicylate

-LRB-

MeSA

compound

number

in

Fig.

-RRB-

-LRB-

-RRB-

-LSB-

-LRB-

E

-RRB-

DMNT

-RSB-

-LRB-

-RRB-

and

-LRB-

E

-RRB-

-LSB-

-LRB-

E

E

-RRB-

TMTT

-RSB-

-LRB-

-RRB-

Herbivory

by

S.

exigua

alone

resulted

in

the

emission

of

similar

amounts

of

-LRB-

E

-RRB-

DMNT

-LRB-

-RRB-

but

amounts

of

MeSA

-LRB-

-RRB-

and

-LRB-

E

E

-RRB-

TMTT

-LRB-

-RRB-

were

small

Instead

S.

exigua-infested

bean

leaves

emitted

large

amounts

of

-LRB-

E

-RRB-

β-ocimene

-LRB-

-RRB-

and

-LRB-

Z

-RRB-

acetate

-LRB-

-RRB-

Multi-species

herbivory

on

bean

plants

induced

the

same

volatile

compounds

as

S.

exigua

feeding

alone

Multi-species-infested

plants

emitted

larger

amounts

of

all

volatile

compounds

than

plants

infested

with

a

single

herbivore

species

except

for

-LRB-

Z

-RRB-

-LRB-

-RRB-

that

was

emitted

in

larger

amounts

by

S.

exigua-infested

plants

and

MeSA

-LRB-

-RRB-

that

was

emitted

in

somewhat

larger

absolute

amounts

by

T.

urticae-infested

plants.In

lima

bean

herbivore

treatment

had

a

significant

effect

on

the

emission

of

-LRB-

Z

-RRB-

-LRB-

-RRB-

-LRB-

E

-RRB-

β-ocimene

-LRB-

-RRB-

-LRB-

Z

-RRB-

acetate

-LRB-

-RRB-

oxime

-LRB-

-RRB-

linalool

-LRB-

-RRB-

-LRB-

-RRB-

hexyl

acetate

-LRB-

-RRB-

β-caryophyllene

-LRB-

-RRB-

indole

-LRB-

-RRB-

-LRB-

E

-RRB-

acetate

-LRB-

-RRB-

-LRB-

Z

-RRB-

β-ocimene

-LRB-

-RRB-

and

two

unknown

compounds

-LRB-

and

-RRB-

-LRB-

all

P

Kruskal

Wallis

tests

Fig.

-RRB-

These

compounds

were

all

induced

in

larger

amounts

by

S.

exigua

and/or

multi-species

herbivory

than

by

T.

urticae

Total

volatile

emission

was

also

significantly

affected

by

treatment

-LRB-

P

Kruskal

Wallis

test

Fig.

-RRB-

We

compared

the

ratio

of

volatiles

emitted

in

the

multi-species

herbivory

treatment

to

the

sum

of

volatiles

emitted

by

the

T.

urticae

and

S.

exigua

treatments

to

determine

whether

infestation

by

two

herbivore

species

simultaneously

had

additive

synergistic

or

antagonistic

effects

Figure

shows

the

average

ratio

of

multi-species

herbivory

to

the

sum

of

T.

urticae

and

S.

exigua

for

lima

bean

Eight

of

compounds

were

significantly

more

strongly

induced

by

multi-species

herbivory

than

by

the

sum

of

the

two

herbivore

species

feeding

alone

suggesting

synergistic

effects

-LRB-

Fig.

-RRB-

These

compounds

included

members

of

various

groups

of

chemicals

for

example

-LRB-

E

-RRB-

acetate

-LRB-

-RRB-

and

-LRB-

Z

-RRB-

β-ocimene

-LRB-

-RRB-

In

addition

more

compounds

had

a

ratio

than

expected

-LRB-

χ2

P

-RRB-

of

the

compounds

was

significantly

less

induced

by

multi-species

herbivory

suggesting

the

absence

of

antagonistic

effects

of

T.

urticae

and

S.

exigua

feeding

simultaneously

on

lima

bean

Volatile

Emission

by

Cucumber

Plants

Nine

compounds

were

induced

by

herbivory

on

cucumber

-LRB-

all

P

Kruskal

Wallis

tests

data

not

shown

-RRB-

The

main

compounds

emitted

by

T.

urticae-infested

cucumber

plants

were

-LRB-

Z

-RRB-

acetate

-LRB-

compound

number

in

Fig.

-RRB-

-LRB-

E

E

-RRB-

α-farnesene

-LRB-

-RRB-

oxime

-LRB-

-RRB-

-LRB-

E

-RRB-

DMNT

-LRB-

-RRB-

and

-LRB-

E

-RRB-

β-ocimene

-LRB-

-RRB-

-LRB-

Fig.

-RRB-

Similar

compounds

were

emitted

in

the

largest

amounts

by

S.

exigua-infested

cucumber

plants

Multi-species

herbivory

resulted

in

a

volatile

blend

that

consisted

of

the

same

compounds

as

the

blends

induced

upon

herbivory

by

each

of

the

herbivore

species

alone

The

multi-species

herbivory

treatment

resulted

in

the

strongest

induction

of

-LRB-

-RRB-

and

-LRB-

E

-RRB-

β-ocimene

-LRB-

-RRB-

while

T.

urticae-infested

plants

emitted

the

largest

amounts

of

-LRB-

Z

-RRB-

acetate

-LRB-

-RRB-

Herbivory

by

T.

urticae

alone

and

multi-species

herbivory

induced

larger

amounts

of

-LRB-

E

E

-RRB-

TMTT

-LRB-

-RRB-

than

single

herbivory

by

S.

exigua

alone

No

MeSA

was

detected

in

any

of

the

cucumber

samples.In

cucumber

herbivore

treatment

had

an

effect

on

the

emission

of

-LRB-

-RRB-

and

-LRB-

E

-RRB-

DMNT

-LRB-

-RRB-

-LRB-

P

Kruskal

Wallis

tests

Fig.

-RRB-

Both

compounds

were

induced

in

larger

amounts

by

T.

urticae

or

multi-species

herbivory

than

by

S.

exigua

Total

volatile

emission

was

not

affected

by

herbivore

treatment

in

cucumber

-LRB-

P

Kruskal

Wallis

test

Fig.

-RRB-

Two

volatile

compounds

-LSB-

-LRB-

E

-RRB-

-LRB-

Z

-RRB-

-LRB-

-RRB-

and

-LRB-

Z

-RRB-

acetate

-LRB-

-RRB-

-RSB-

were

induced

significantly

less

by

multi-species

herbivory

than

by

the

sum

of

T.

urticae

and

S.

exigua

-LRB-

Fig.

-RRB-

suggesting

the

presence

of

antagonistic

effects

of

the

two

herbivore

species

feeding

on

cucumber

The

seven

other

compounds

were

equally

induced

by

multispecies

herbivory

and

the

sum

of

the

two

herbivores

feeding

alone

indicating

an

additive

effect

of

T.

urticae

and

S.

exigua

The

distribution

of

compounds

with

a

ratio

or

did

not

differ

from

-LRB-

χ2

P

-RRB-

Responses

of

P.

persimilis

We

tested

the

preferences

of

the

predatory

mite

P.

persimilis

for

the

volatile

blends

analyzed

above

in

a

Y-tube

olfactometer

On

bean

and

cucumber

plants

predatory

mites

preferred

HIPV

induced

by

multi-species

herbivory

to

blends

induced

by

either

T.

urticae

or

S.

exigua

alone

-LRB-

Fig.

P

binomial

tests

-RRB-

Fig.

of

P.

persimilis

to

volatile

blends

in

the

Y-tube

olfactometer

Odor

sources

consisted

of

four

leaves

from

lima

bean

-LRB-

a

and

b

-RRB-

or

cucumber

plant

-LRB-

c

and

d

-RRB-

simultaneously

infested

by

Tetranychus

urticae

and

Spodoptera

exigua

or

infested

by

one

of

the

herbivore

species

alone

-LRB-

S.

exigua

a

and

c

T.

urticae

b

and

d

-RRB-

Bars

present

the

overall

percentages

of

predators

choosing

for

each

odor

source

Numbers

in

bars

are

the

total

numbers

of

predators

responding

to

each

odor

source

Choices

between

odor

sources

were

analyzed

with

a

two-sided

binomial

test

-LRB-

P

P

-RRB-

Discussion

We

investigated

volatile

emissions

by

lima

bean

and

cucumber

plants

upon

single

and

multi-species

herbivory

by

T.

urticae

and

S.

exigua

In

lima

bean

we

found

that

most

compounds

were

more

strongly

induced

by

multi-species

herbivory

than

by

the

sum

of

each

of

the

herbivores

feeding

separately

-LRB-

Fig.

-RRB-

This

suggests

that

the

two

herbivores

feeding

together

on

the

same

plant

have

more

than

an

additive

effect

on

volatile

emission

potentially

indicating

that

biosynthetic

pathways

may

act

synergistically

It

is

also

possible

that

one

or

both

herbivore

species

inflicted

more

damage

on

multi-species-infested

plants

than

on

plants

with

conspecifics

only

However

it

is

unlikely

that

spider

mite

feeding

was

affected

by

the

presence

of

S.

exigua

because

in

a

preliminary

experiment

oviposition

rates

of

mites

which

are

correlated

with

food

intake

rates

were

similar

on

leaf

discs

with

or

without

S.

exigua

damage

-LRB-

de

Boer

et

al.

unpublished

-RRB-

Some

studies

have

observed

that

feeding

by

S.

exigua

is

enhanced

by

the

presence

of

aphids

or

a

fungal

pathogen

-LRB-

Rodriguez-Saona

et

al.

Cardoza

and

Tumlinson

-RRB-

but

other

studies

have

found

no

effect

of

the

presence

of

whiteflies

or

a

fungus

-LRB-

Rodriguez-Saona

et

al.

Rostás

et

al.

-RRB-

In

contrast

to

bean

we

found

that

in

cucumber

plants

two

volatile

compounds

were

induced

less

by

multi-species

herbivory

than

by

the

sum

of

the

two

herbivores

feeding

separately

suggesting

that

their

induction

was

suppressed

by

simultaneous

feeding

of

T.

urticae

and

S.

exigua

Whether

this

reduction

is

caused

by

a

negative

interaction

between

the

signal

transduction

pathways

induced

by

spider

mites

and

beet

armyworms

or

to

reduced

feeding

of

one

or

both

herbivore

species

as

a

result

of

feeding

on

the

same

plant

remains

to

be

investigated

From

our

data

it

appears

that

plant

species

is

an

important

determinant

in

the

way

in

which

herbivore-induced

defense

pathways

interact

upon

multispecies

herbivory

The

plant

hormones

salicylic

acid

-LRB-

SA

-RRB-

and

jasmonic

acid

-LRB-

JA

-RRB-

play

important

roles

in

plant

defense

pathways

and

the

production

of

HIPV

-LRB-

e.g.

Kessler

and

Baldwin

van

Poecke

and

Dicke

-RRB-

Interaction

between

these

pathways

may

occur

for

example

when

SA

inhibits

JA-dependent

defense

pathways

-LRB-

e.g.

Doares

et

al.

Niki

et

al.

Engelberth

et

al.

-RRB-

To

determine

whether

synergistic

-LRB-

lima

bean

-RRB-

and

antagonistic

-LRB-

cucumber

-RRB-

interactions

between

biosynthetic

defense

pathways

caused

the

changes

in

HIPV

blends

that

we

observed

endogenous

levels

of

JA

and

SA

should

be

determined

in

future

studies

Arimura

et

al.

-LRB-

-RRB-

showed

that

both

JA

and

SA

levels

are

significantly

elevated

in

lima

bean

after

d

of

spider

mite

feeding

whereas

several

Spodoptera

species

are

known

to

increase

JA

levels

in

corn

and

broad

bean

-LRB-

Blechert

et

al.

Schmelz

et

al.

-RRB-

We

are

not

aware

of

analyses

of

SA

levels

in

response

to

Spodoptera

feeding

No

studies

of

JA

and

SA

levels

in

plants

upon

multi-species

herbivory

are

known

to

us

either

Another

important

question

that

needs

to

be

addressed

is

the

effect

of

herbivore

sequence

on

volatile

emission

patterns

since

in

nature

two

herbivore

species

may

infest

an

individual

plant

sequentially

In

fact

some

herbivore

species

are

known

to

be

attracted

to

HIPV

themselves

-LRB-

e.g.

Bolter

et

al.

Kalberer

et

al.

-RRB-

but

spider

mites

are

not

attracted

to

S.

exigua-infested

lima

bean

plants

-LRB-

Horiuchi

et

al.

-RRB-

To

determine

whether

the

differences

in

volatile

profiles

upon

multi-species

herbivory

and

single-species

herbivory

are

relevant

in

an

ecological

context

we

investigated

the

behavior

of

the

predatory

mite

P.

persimilis

a

specialist

natural

enemy

of

spider

mites

Our

results

show

that

P.

persimilis

prefers

volatiles

induced

by

multi-species

herbivory

by

spider

mites

and

the

non-prey

caterpillar

S.

exigua

to

volatiles

induced

by

one

of

the

herbivore

species

feeding

alone

-LRB-

Fig.

-RRB-

The

strong

preference

of

P.

persimilis

for

the

volatiles

induced

by

multi-species

herbivory

may

be

explained

by

the

relatively

large

amount

of

some

specific

compounds

Of

the

three

major

compounds

emitted

by

spider

mite-infested

lima

bean

two

namely

-LRB-

E

E

-RRB-

TMTT

and

especially

-LRB-

E

-RRB-

DMNT

were

induced

more

strongly

by

multi-species

herbivory

whereas

induction

of

the

third

MeSA

was

somewhat

reduced

-LRB-

Fig.

-RRB-

Of

the

five

major

compounds

emitted

by

spider

mite-infested

cucumber

four

were

induced

more

strongly

by

multi-species

herbivory

-LRB-

E

-RRB-

DMNT

-LRB-

E

-RRB-

β-ocimene

-LRB-

E

E

-RRB-

α-farnesene

and

oxime

while

-LRB-

Z

-RRB-

acetate

emission

was

reduced

-LRB-

Fig.

-RRB-

-LRB-

E

-RRB-

DMNT

-LRB-

E

E

-RRB-

TMTT

and

-LRB-

E

-RRB-

β-ocimene

are

known

attractants

for

P.

persimilis

-LRB-

Dicke

et

al.

de

Boer

et

al.

-RRB-

and

-LRB-

E

E

-RRB-

TMTT

can

be

used

by

P.

persimilis

to

discriminate

between

complex

blends

of

HIPV

-LRB-

de

Boer

et

al.

-RRB-

Similarly

when

S.

exigua-induced

volatiles

are

compared

to

the

blend

induced

by

multi-species

herbivory

all

of

these

compounds

are

produced

in

larger

amounts

in

the

latter

This

suggests

that

a

greater

emission

of

-LRB-

the

sum

of

-RRB-

attractive

compounds

may

be

the

main

determinant

in

attracting

the

predatory

mite

P.

persimilis

Previous

studies

on

the

responses

of

parasitoid

wasps

to

HIPV

also

demonstrated

a

preference

for

HIPV

induced

by

multi-species

herbivory

compared

to

single-species

herbivory

-LRB-

Shiojiri

et

al.

Vos

et

al.

Cardoza

et

al.

Moayeri

et

al.

-RRB-

Rodriguez-Saona

et

al.

-LRB-

-RRB-

even

showed

that

naïve

Cotesia

marginiventris

females

were

only

attracted

to

tomato

plants

infested

with

their

host

S.

exigua

when

the

same

plant

was

also

infested

with

aphids

The

presence

of

aphids

thus

made

the

host-infested

plants

more

detectable

The

opposite

i.e.

multi-species

herbivory-induced

volatiles

being

less

attractive

than

volatiles

induced

by

only

the

host

has

been

found

in

two

cases

C.

plutellae

wasps

preferred

volatiles

induced

by

their

host

P.

xylostella

to

volatiles

induced

by

their

host

and

the

non-host

caterpillar

P.

rapae

-LRB-

Shiojiri

et

al.

-RRB-

and

C.

marginiventris

as

well

as

the

entomopathogenic

nematode

H.

megidis

were

less

attracted

to

volatiles

from

maize

plants

that

were

infested

by

a

non-host

in

addition

to

their

host

-LRB-

Rasmann

and

Turlings

-RRB-

In

such

cases

the

presence

of

non-host

or

non-prey

herbivores

may

decrease

the

detectability

or

reliability

of

HIPV

cues

for

natural

enemies

For

example

feeding

by

a

non-prey

or

non-host

herbivore

may

suppress

the

induction

of

volatile

compounds

used

by

natural

enemies

Multi-species

herbivory

thus

adds

a

new

dimension

to

the

trade-off

between

reliability

and

detectability

of

searching

cues

used

by

natural

enemies

of

herbivorous

arthropods

-LRB-

Vet

and

Dicke

-RRB-

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O 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O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

food webs
methyl salicylate
signal transduction

indirect defense
terpenes
tritrophic interactions
gc-ms


BioMagResBank

-LRB-

BMRB

-RRB-

as

a

partner

in

the

Worldwide

Protein

Data

Bank

-LRB-

wwPDB

-RRB-

new

policies

affecting

biomolecular

NMR

depositions

We

describe

the

role

of

the

BioMagResBank

-LRB-

BMRB

-RRB-

within

the

Worldwide

Protein

Data

Bank

-LRB-

wwPDB

-RRB-

and

recent

policies

affecting

the

deposition

of

biomolecular

NMR

data

All

PDB

depositions

of

structures

based

on

NMR

data

must

now

be

accompanied

by

experimental

restraints

A

scheme

has

been

devised

that

allows

depositors

to

specify

a

representative

structure

and

to

define

residues

within

that

structure

found

experimentally

to

be

largely

unstructured

The

BMRB

now

accepts

coordinate

sets

representing

three-dimensional

structural

models

based

on

experimental

NMR

data

of

molecules

of

biological

interest

that

fall

outside

the

guidelines

of

the

Protein

Data

Bank

-LRB-

i.e.

the

molecule

is

a

peptide

with

or

fewer

residues

a

polynucleotide

with

or

fewer

residues

a

polysaccharide

with

or

fewer

sugar

residues

or

a

natural

product

-RRB-

provided

that

the

coordinates

are

accompanied

by

representation

of

the

covalent

structure

of

the

molecule

-LRB-

atom

connectivity

-RRB-

assigned

NMR

chemical

shifts

and

the

structural

restraints

used

in

generating

model

The

BMRB

now

contains

an

archive

of

NMR

data

for

metabolites

and

other

small

molecules

found

in

biological

systems

Organization

The

BioMagResBank

-LRB-

BMRB

-RRB-

the

repository

for

experimental

and

derived

data

gathered

from

NMR

spectroscopic

studies

of

biological

molecules

-LRB-

Ulrich

et

al.

-RRB-

has

been

a

member

of

the

Worldwide

Protein

Data

Bank

-LRB-

wwPDB

-RRB-

since

-LRB-

Berman

et

al.

-RRB-

Other

wwPDB

partners

include

the

Research

Collaboratory

for

Structural

Biology

-LRB-

RCSB

PDB

-RRB-

the

Protein

Data

Bank

Japan

-LRB-

PDBj

-RRB-

and

the

Macromolecular

Structure

Database

at

the

European

Bioinformatics

Institute

-LRB-

MSD

EBI

-RRB-

These

four

groups

work

closely

together

with

the

goal

of

maintaining

a

single

Protein

Data

Bank

archive

of

macromolecular

structural

data

that

is

freely

and

publicly

available

to

the

global

community

The

wwPDB

Advisory

Committee

-LRB-

wwPDBAC

-RRB-

which

provides

oversight

and

advice

meets

yearly

and

currently

is

chaired

by

Stephen

K.

Burley

This

committee

consists

of

the

leaders

of

the

four

sites

plus

two

scientists

nominated

by

each

of

the

four

partner

sites

Additional

ex

officio

members

include

scientists

representing

various

stakeholder

communities

-LRB-

e.g.

International

Union

of

Crystallography

International

Council

on

Magnetic

Resonance

in

Biological

Systems

electron

microscopy

structural

genomics

-RRB-

and

representatives

of

the

international

funding

agencies

that

support

the

wwPDB

member

sites

On

matters

pertaining

to

NMR

spectroscopy

the

wwPDB

is

advised

by

members

of

the

wwPDB

NMR

Task

Force

-LRB-

NMR

TF

-RRB-

which

is

chaired

by

Robert

Kaptein

-LRB-

a

wwPDBAC

member

-RRB-

Historically

members

of

this

TF

have

been

nominated

by

the

wwPDB

leadership

Additional

interested

persons

are

welcome

to

join

and

participate

The

wwPDB

NMR

TF

meets

periodically

-LRB-

usually

more

than

once

each

year

-RRB-

at

international

NMR

conferences

Data

remediation

Together

with

other

wwPDB

partners

the

BMRB

participated

in

the

recently

completed

remediation

of

the

full

PDB

archive

-LRB-

Henrick

et

al.

-RRB-

Among

the

changes

was

adoption

of

uniform

atom

nomenclature

in

accordance

with

longstanding

IUPAC

recommendations

-LRB-

Markley

et

al.

-RRB-

BMRB

's

major

contribution

to

the

remediation

was

to

parse

and

organize

restraints

for

NMR

structures

into

the

NMR

Restraints

Grid

-LRB-

-RRB-

-LRB-

Doreleijers

et

al.

-RRB-

Requirement

for

structure

factors

and

constraints

Over

the

past

years

the

wwPDB

organization

in

consultation

with

other

members

of

the

crystallographic

and

NMR

communities

reviewed

policies

concerning

data

deposition

These

deliberations

led

to

the

decision

supported

by

the

wwPDBAC

and

wwPDB

NMR

TF

at

their

most

recent

meetings

that

all

PDB

depositions

must

be

accompanied

by

structure

factors

-LRB-

for

X-ray

structures

-RRB-

and

restraints

-LRB-

for

NMR

structures

-RRB-

These

requirements

listed

below

were

formally

announced

on

November

and

are

scheduled

to

go

into

effect

on

February

The

wwPDB

shall

require

deposition

of

structure

factor

amplitudes/intensities

-LRB-

for

crystal

structure

depositions

-RRB-

and/or

NMR

restraints

-LRB-

for

NMR

structure

depositions

-RRB-

in

addition

to

atomic

coordinates

as

a

prerequisite

for

receiving

a

PDB

ID.The

wwPDB

leadership

shall

inform

the

relevant

journals

of

this

new

policy

and

will

suggest

that

Instructions

to

the

Authors

read

as

follows

For

papers

describing

structures

of

biological

macromolecules

atomic

coordinates

and

the

associated

experimental

data

-LRB-

structure

factor

amplitudes/intensities

and/or

NMR

restraints

-RRB-

must

be

deposited

at

a

member

site

of

the

Worldwide

Protein

Data

Bank

-LRB-

-RRB-

RCSB

PDB

-LRB-

-RRB-

MSD-EBI

-LRB-

-RRB-

PDBj

-LRB-

-RRB-

or

BMRB

-LRB-

-RRB-

The

PDB

ID

should

be

included

in

the

manuscript

Authors

must

agree

to

release

the

atomic

coordinates

and

deposited

experimental

data

when

the

associated

article

is

published

Questions

relating

to

depositions

should

be

sent

to

info@wwpdb.org

Chemical

shift

depositions

remain

optional

These

bodies

also

considered

a

proposal

by

members

of

the

community

that

NMR

structure

depositions

be

accompanied

by

a

BMRB

deposition

of

assigned

chemical

shifts

Although

it

was

decided

that

this

requirement

should

not

be

made

mandatory

at

present

the

wwPDB

NMR

TF

strongly

recommend

that

these

valuable

data

be

deposited

Small

molecule

NMR

structures

At

its

meeting

the

wwPDBAC

discussed

the

question

of

small

molecule

NMR

structures

that

do

not

comply

with

PDB

guidelines

X-ray

structures

of

such

compounds

are

commonly

deposited

in

the

Cambridge

Structural

Database

-LRB-

CSD

-RRB-

but

no

such

archive

is

available

for

NMR

structures

Subsequently

the

wwPDBAC

approached

BMRB

with

a

request

that

it

consider

supporting

this

effort

BMRB

developed

the

following

proposal

which

was

brought

before

its

External

Advisory

Board

in

May

BMRB

will

consider

accepting

coordinate

sets

representing

three-dimensional

structural

models

provided

that

the

following

criteria

are

met

The

molecule

falls

outside

the

guidelines

of

the

Protein

Data

Bank

-LRB-

i.e.

the

molecule

is

a

peptide

with

or

fewer

residues

a

polynucleotide

with

or

fewer

residues

a

polysaccharide

with

or

fewer

sugar

residues

or

a

natural

product

-RRB-

The

molecule

is

of

biological

interestThe

structural

model

-LRB-

s

-RRB-

are

based

on

experimental

NMR

dataThe

coordinates

are

accompanied

by

A

representation

of

the

covalent

structure

of

the

molecule

-LRB-

atom

connectivity

-RRB-

Assigned

NMR

chemical

shifts

for

the

moleculeStructural

restraints

used

in

generating

the

structural

model

For

depositions

meeting

these

criteria

BMRB

encourages

that

authors

submit

their

primary

-LRB-

time-domain

-RRB-

data

tables

of

NOEs

and

other

relevant

information

This

policy

was

announced

at

the

most

recent

meetings

of

the

wwPDBAC

and

wwPDB

NMR

TF

Small

molecule

NMR

structures

meeting

the

above

criteria

can

be

deposited

at

the

SMSDep

website

developed

by

BMRB

and

PDBj-BMRB

-LRB-

-RRB-

With

small

molecule

structure

depositions

the

BMRB

accession

code

serves

to

identify

the

structure

as

well

as

the

supporting

NMR

data

-LRB-

questions

about

small

molecule

NMR

structure

depositions

should

be

addressed

to

bmrbhelp@bmrb.wisc.edu

-RRB-

Depositor

defined

regions

of

local

disorder

in

structures

At

the

request

of

the

wwPDB

NMR

TF

BMRB

created

tags

enumerations

and

formal

PDBx

dictionary

-LRB-

Westbrook

et

al.

-RRB-

entries

for

the

following

purposes

To

separately

specify

the

single

structural

model

chosen

by

the

authors

to

best

represent

the

solution

structure

and

to

describe

how

it

was

derived.To

describe

uncertainty

in

the

structural

model

-LRB-

on

a

per-residue

basis

-RRB-

and

to

denote

residues

found

experimentally

to

be

largely

unstructured.To

describe

uncertainty

in

the

structural

model

-LRB-

on

a

per-atom

basis

-RRB-

both

qualitatively

and

quantitatively

depending

on

the

available

data

A

detailed

draft

was

refined

by

RCSB

PDB

and

circulated

to

the

wwPDB

NMR

TF

These

specifications

make

it

possible

for

an

author

to

clearly

define

those

regions

that

are

experimentally

determined

to

be

structured

and

those

that

are

not

This

information

will

be

available

in

the

mmCIF

version

of

the

PDB

entry

and

can

be

used

by

software

developers

in

displaying

structures

Metabolomics

data

at

BMRB

In

collaboration

with

the

Madison

Metabolomics

Consortium

and

the

Human

Metabolome

Database

-LRB-

HMDB

-RRB-

BMRB

has

developed

an

archive

of

NMR

data

for

metabolites

and

other

small

molecules

found

in

biological

systems

-LRB-

Ulrich

et

al.

-RRB-

A

metabolomics

deposition

tool

under

construction

at

BMRB

will

enable

others

to

submit

data

to

add

to

this

collection

Compounds

are

cross-referenced

to

PDB

ligands

and

the

spectral

information

should

be

of

interest

to

scientists

studying

macromolecule

ligand

complexes

The

site

is

mirrored

by

PDBj

and

CERM

in

Florence

Italy

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

metabolomics
nmr structure
structural restraints


Middle

Segment

Pancreatectomy

A

Useful

Tool

in

the

Management

of

Pancreatic

Neoplasms

Small

benign

or

low-grade

malignant

tumors

located

in

the

neck

of

the

pancreas

are

usually

treated

with

enucleation

However

if

enucleation

is

too

risky

because

of

possible

damage

of

the

main

pancreatic

duct

standard

pancreatic

resections

are

performed

Such

operations

can

lead

to

impaired

long-term

exocrine

endocrine

function

Middle

segment

pancreatectomy

consists

of

a

limited

resection

of

the

midportion

of

the

pancreas

and

can

be

performed

in

selected

patients

affected

by

tumors

of

the

pancreatic

neck

Middle

segment

pancreatectomy

is

a

safe

and

feasible

procedure

for

treating

tumors

of

the

pancreatic

neck

in

experienced

hands

it

is

associated

with

no

mortality

but

with

high

morbidity

even

if

the

rate

of

clinical

pancreatic

fistula

is

about

Moreover

it

allows

a

surgeon

to

preserve

pancreatic

parenchyma

and

consequently

long-term

endocrine

and

exocrine

pancreatic

function

Introduction

Whereas

neoplastic

lesion

located

in

the

pancreatic

head

or

body-tail

are

usually

resected

by

pancreaticoduodenectomy

or

distal

pancreatectomy

tumors

in

the

neck

represent

a

real

challenge

for

a

surgeon

In

these

cases

standard

or

extended

pancreatectomies

performed

for

benign

or

borderline

cases

can

determine

the

loss

of

a

great

amount

of

glandular

tissue

significantly

increasing

the

risk

of

diabetes

impaired

exocrine

function

and

splenic

loss

Enucleation

would

be

an

adequate

alternative

for

small

benign

and

low-grade

malignant

tumors

such

as

endocrine

and

cystic

neoplasms

of

the

pancreas

Unfortunately

this

conservative

procedure

can

not

be

always

applicable

When

the

neoplastic

lesion

measures

up

to

cm

or

more

or

it

is

encased

within

the

pancreatic

gland

enucleation

is

associated

with

a

high

risk

of

Wirsung

's

duct

damage

moreover

in

the

case

of

tumors

with

uncertain

biological

behavior

this

approach

should

be

avoided

because

of

the

risk

of

tumor

Letton

and

reported

for

the

first

time

in

the

English

literature

in

two

cases

of

traumatic

midpancreatic

transection

followed

by

a

reconstruction

with

a

Roux-en-Y

jejunal

loop

anastomized

to

the

distal

part

of

the

gland

Dagradi

and

Serio

from

our

own

Department

of

Surgery

were

the

first

in

to

propose

middle

pancreatectomy

with

an

oncological

indication

treating

a

pancreatic

insulinoma

Subsequently

other

authors

reported

cases

of

resection

of

the

middle

pancreas

of

varying

extent

using

various

terms

such

as

central

pancreatectomy

middle

segment

pancreatectomy

segmental

pancreatectomy

and

intermediate

pancreatectomy

The

underlying

indications

for

surgery

ranged

from

chronic

pancreatitis

to

benign

uncertain

behavior

or

low-grade

malignant

exocrine

and

endocrine

Different

techniques

were

adopted

for

gastrointestinal

reconstruction

including

jejunal

anastomosis

of

both

the

proximal

and

distal

stump

or

of

only

the

distal

stump

with

pancreaticoduodenal

or

pancreaticogastric

anastomosis

Surgical

Technique

The

abdomen

is

entered

through

a

midline

incision

The

gastrocolic

ligament

is

opened

preserving

the

gastroepiploic

vessels

and

the

pancreatic

gland

is

exposed

The

posterior

peritoneum

along

the

superior

and

inferior

margin

of

the

pancreas

is

incised

The

superior

mesenteric

vein

and

the

portal

vein

must

be

identified

and

their

surfaces

cleared

below

the

gland

The

plane

between

the

superior

mesenteric

and

portal

vein

should

be

teased

apart

The

splenic

artery

and

vein

are

dissected

free

and

separated

from

the

gland

Some

venous

tributaries

to

the

portomesenteric

axis

and

some

minor

collaterals

of

the

splenic

artery

can

be

ligated

Then

the

posterior

surface

of

the

pancreatic

neck

is

isolated

from

the

portomesenteric

axis

and

a

ribbon

is

passed

behind

the

gland

to

elevate

it

Sutures

are

placed

along

the

superior

and

inferior

margins

to

indicate

where

the

proximal

and

distal

transection

should

be

performed

and

to

ligate

those

vessels

running

along

the

margins

The

segment

of

the

pancreas

with

the

tumor

is

subsequently

transected

through

a

knife

or

a

stapler

to

the

left

and

to

the

right

of

the

lesion

The

cephalic

stump

is

sutured

with

interrupted

stitches

after

elective

ligation

of

the

Wirsung

's

duct

or

by

means

of

a

stapler

A

small

stent

is

placed

in

the

main

pancreatic

duct

while

performing

pancreojejunostomy

or

pancreogastrostomy

the

stent

can

be

left

in

place

even

if

in

our

experience

we

have

never

done

it

Two

closed-system

suction

drains

are

used

to

drain

the

cephalic

stump

of

the

gland

and

the

pancreaticojejunostomy/pancreaticogastrostomy

Discussion

It

has

been

shown

that

standard

pancreatic

resections

are

nowadays

associated

with

low

mortality

and

morbidity

if

performed

in

high-volume

centers

by

experienced

surgeons

It

is

remarkable

that

this

type

of

surgery

can

lead

to

long-term

complications

such

as

diabetes

exocrine

insufficiency

and

late

postsplenectomy

The

incidence

of

postoperative

exocrine

and

endocrine

impairment

is

not

predictable

in

patients

with

apparently

normal

pancreas

Factors

such

as

fibrosis

of

the

remnant

Wirsung

's

duct

obstruction

preexisting

chronic

pancreatitis

benign

or

malignant

disease

and

subclinical

diabetes

may

play

a

role

as

risk

factors

After

standard

left-sided

resection

there

is

an

increased

incidence

of

endocrine

impairment

and

onset

of

diabetes

reported

from

to

of

patients

it

is

reasonable

that

the

extent

of

the

resection

is

strictly

related

to

the

incidence

of

endocrine

exocrine

long-term

For

all

these

reasons

more

conservative

surgical

techniques

have

been

advocated

for

small

benign

or

low-grade

malignant

tumors

located

in

the

neck

of

the

gland

aimed

for

sparing

as

much

as

possible

pancreatic

parenchyma

Whenever

neoplastic

lesions

are

not

small

and

superficial

enough

to

be

simply

enucleated

middle

segment

pancreatectomy

should

be

considerated

Middle

segment

pancreatectomy

accounts

for

only

of

the

pancreatic

resections

performed

at

our

institution

and

about

cases

have

been

reported

in

the

English

this

means

careful

selection

of

patients

In

fact

the

small

number

of

patients

who

underwent

this

type

of

operation

is

related

to

different

factors

specific

localizations

of

the

neoplasm

well-selected

indications

-LRB-

benign

or

low-grade

malignant

tumors

-RRB-

and

a

distal

pancreatic

stump

of

at

least

cm

in

length

Some

have

reported

that

this

operation

can

be

performed

only

in

the

case

of

small

tumors

-LRB-

cm

in

diameter

-RRB-

in

our

experience

although

the

mean

diameter

of

the

resected

lesions

was

mm

we

have

safely

performed

middle

segment

resection

for

tumor

measuring

more

than

cm

harboring

from

the

anterior

face

of

the

pancreas

Middle

segment

pancreatectomy

was

also

occasionally

used

for

malignant

disease

two

islet

cell

carcinomas

one

vipoma

who

subsequently

developed

hepatic

metastases

one

cystadenocarcinoma

and

one

carcinoma

in

In

the

past

we

have

also

performed

this

operation

for

malignant

tumor

but

we

had

pancreatic

recurrence

of

the

tumor

in

two

patients

-LRB-

one

affected

by

metastasis

and

one

by

intraductal

papillary

mucinous

neoplasms

-LSB-

IPMN

-RSB-

with

in

situ

carcinoma

-RRB-

moreover

two

patients

with

adenoma

and

borderline

main

duct

IPMN

had

a

tumor

recurrence

in

the

pancreatic

gland

Thus

we

believe

that

in

patients

affected

by

primary

or

metastatic

malignant

tumor

a

standard

resection

would

be

more

appropriate

Moreover

middle

pancreatectomy

in

our

experience

should

also

be

avoided

in

patients

affected

by

IPMN

especially

main

duct

type

because

of

their

potential

malignity

and

the

possibility

to

have

different

degrees

of

dysplasia

along

the

Wirsung

's

duct

in

the

same

patients

The

surgeon

must

be

sure

to

achieve

tumor-free

proximal

and

distal

resection

margins

after

performing

middle

segment

pancreatectomy

and

for

this

reason

frozen

section

examination

is

mandatory

Middle

segment

pancreatectomy

is

a

meticulous

procedure

There

is

the

possibility

of

leaks

from

both

the

closed

cut

edge

of

the

head

and

the

pancreaticojejunostomy

considering

that

in

most

patients

we

are

dealing

with

a

normal

soft

pancreatic

texture

with

a

small

Wirsung

's

duct

Thus

not

only

great

care

must

be

taken

in

selecting

the

patients

who

will

benefit

from

this

operation

but

also

an

experienced

pancreatic

surgeon

working

in

a

high-volume

center

is

required

for

performing

the

procedure

Median

pancreatectomy

is

reported

to

be

associated

with

no

mortality

but

with

a

high

postoperative

morbidity

above

all

consisting

of

pancreatic

fistula

In

our

experience

the

clinical

pancreatic

fistula

rates

after

pancreaticoduodenectomy

and

left

pancreatectomy

are

and

respectively

Between

January

and

December

patients

underwent

middle

segment

pancreatectomy

at

our

institution

The

incidence

of

pancreatic

fistula

according

to

the

International

Study

Group

on

Pancreatic

Fistula

was

It

is

remarkable

that

most

patients

complained

of

Grade

A

fistula

which

is

a

biochemical

fistula

without

any

clinical

impact

whereas

patients

-LRB-

-RRB-

developed

a

grade

B

or

C

fistula

which

required

prolonged

in-hospital

stay

In

almost

all

patients

the

conservative

management

was

successful

no

one

underwent

reoperation

and

in

four

cases

intraabdominal

collections

were

treated

with

ultrasound-guided

drainage

The

mortality

rate

was

zero

The

risk

of

developing

a

pancreatic

fistula

must

be

taken

into

account

in

the

preoperative

decision

making

we

believe

that

this

risk

is

acceptable

when

the

procedure

is

performed

in

a

high-volume

center

and

for

patients

with

a

long-life

expectancy

such

as

young

or

middle-aged

people

affected

by

benign

or

low-grade

tumors

The

most

important

advantage

of

middle

segment

pancreatectomy

is

the

good

endocrine

and

exocrine

long-term

function

Iacono

et

al.

in

a

series

of

patients

demonstrated

that

postoperative

oral

glucose

tolerance

pancreaticolauryl

and

fecal

fat

excretion

were

normal

in

all

cases

and

they

studied

six

patients

pre

and

postoperatively

with

oral

glucose

tolerance

test

showing

no

significant

differences

before

and

after

surgery

Moreover

Sperti

et

al.

showed

in

a

review

of

the

literature

no

case

of

impaired

endocrine

function

in

evaluable

patients

whereas

exocrine

function

was

reported

to

be

normal

in

out

of

Another

advantage

of

this

procedure

is

the

possibility

to

preserve

the

spleen

preventing

the

risk

of

postsplenectomy

sepsis

and

hematologic

disorders

which

is

low

but

exists

in

an

adult

In

conclusion

middle

segment

pancreatectomy

is

a

safe

and

technically

feasible

surgical

approach

for

removing

pancreatic

neck

tumors

in

well-selected

patients

in

experienced

hands

it

is

associated

with

no

mortality

but

with

high

morbidity

Most

of

the

complications

do

no

require

reoperation

or

prolonged

in-hospital

stay

and

can

be

successfully

managed

conservatively

Moreover

it

allows

the

surgeon

to

preserve

pancreatic

parenchyma

and

consequently

long-term

endocrine

and

exocrine

pancreatic

function

B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O

middle segment pancreatectomy
pancreatic function

pancreatic resection
pancreatic tumors
surgical complications