bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasmodesmata and solute exchange in the phloem
Authors: Turgeon Robert
Published: September 2002

Photoassimilates and other substances
accumulate against concentration gradients in the phloem, a process known as
loading. In mature leaves, the sieve element–companion cell complexes
(SE–CCCs) of minor veins, where loading occurs, are connected to
surrounding cells by plasmodesmata. These pores appear to participate in
loading in plants that translocate raffinose and stachyose, but in sucrose-
and polyol-translocating species their function is less certain. Indeed, large
numbers of plasmodesmata between the SE–CCCs and surrounding cells
should cause a dissolution of the concentration gradient unless the size
exclusion limit of the pores is small enough to retain accumulated solute
species. In leaves of willow, Salix babylonica L., a
sucrose-translocating plant with a high degree of symplastic connectivity into
the minor vein phloem, the sucrose concentration gradient is absent between
mesophyll and phloem, leading to the conclusion that phloem loading does not
occur. Once inside the SE–CCC, solute may be able to pass freely between
sieve elements and companion cells since they are also symplastically
connected. However, due to net flux into the sieve tubes in source leaves,
this should cause a continual drain of metabolic intermediates out of
companion cells. It is proposed that this transport step is regulated in minor
veins to prevent continual loss of needed solute molecules to the
translocation stream.
Vacuolar chain elongation of raffinose oligosaccharides in Ajuga reptans
Authors: Braun Renate , Keller Felix
Published: September 2002

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999
Galactan : galactan galactosyltransferase (GGT) is the key enzyme responsible
for the accumulation of long-chain raffinose family oligosaccharides (RFOs;
α-D-galn(1,6) α-D-glc(1,2) β-D-fru) in
Ajuga reptans L. leaves during autumn and winter. The
exact subcellular location of GGT is not known and its elucidation was the aim
of this paper. A method for the isolation of vacuoles from
A. reptans mesophyll protoplasts was developed using a
pH and osmotic shock to rupture the plasma membrane selectively. By comparing
protoplasts with vacuoles, GGT was confirmed to be a vacuolar enzyme. By
comparing vacuoles with tonoplast vesicles and cell sap fractions, GGT was
further shown to reside in the cell sap and not in the tonoplast. These
findings suggest the need for a tonoplast-bound mechanism for the transport of
short-chain RFOs such as stachyose or raffinose into the vacuole for
subsequent chain elongation.
Plant invertase inhibitors: expression in cell culture and during plant development
Authors: Greiner Steffen , Köster Ulrike , Lauer Katja , Rosenkranz Heiko , Vogel Rolf , Rausch Thomas
Published: September 2002

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999.
We have recently cloned cDNAs encoding two invertase inhibitors from
Nicotiana tabacum, Nt-inh1, an
apoplastic isoform, and Nt-inhh, a vacuolar isoform
(Greiner et al. (1998) Plant Phys.
116, 733–742; Greiner et al.
(1999) Nature/Biotech. 17,
708–711). A database search revealed the presence of related sequences
in other dicot families. Here we report the presence of
Nt-inh1-related proteins (INH-RPs) in apoplastic
fractions from Chenopodium rubrum and
Daucus carota suspension-culture cells. Furthermore, we
demonstrate that, in Lycopersicon esculentum, the
expression of INH-RPs is highly regulated during plant development. In
immature tomato fruits two INH-RP isoforms are expressed, whereas in mature
fruit a single isoform is detected. Sequential extraction of apoplastic and
intracellular fractions from mature fruit pericarp tissue revealed that the
major portion of invertase and INH-RP are localized in the vacuole. Recovery
of the non-glycosylated INH-RP with the glycosylated invertase from the
Concanavalin A-bound fraction indicates that INH-RP forms a stable complex
with vacuolar invertase. As Nt-inh1 and INH-RP from
different species contain four conserved cysteine residues, we have compared
the inhibitory activity of oxidized and dithiothreitol (DTT)-treated
recombinant Nt-inh1 protein. Only the oxidized form is
active as an invertase inhibitor. Its higher mobility during sodium dodecyl
sulfate–gel electrophoresis, as compared to DTT-treated
Nt-inh1, suggests that disulfide bridge(s) prevent the
inhibitor from unfolding. A mechanism is proposed for the post-translational
inactivation of cell wall and vacuolar invertases via invertase inhibitors
during critical stages of plant development.
Sieve element and companion cell: the story of the comatose patient and the hyperactive nurse
Authors: van Bel Aart J. E. , Knoblauch Michael
Published: September 2002

Sieve elements and companion cells constitute
the modules of the conducting elements in the phloem ofAngiosperms.
Consequently, phloem transport basically relies on the concerted action of the
sieve element/companion cell complexes. Sieve elements and companion cells
are highly interactive units and show an extreme division of labour as
exemplified by their state of life. Whereas the sieve element is almost
‘clinically’ dead, the companion cell is a paragon of bubbling
activity. In the course of evolution, the sieve element has sacrificed all of
its genetic and most of its metabolic equipment to serve photoassimilate
translocation. A small part of the structural and metabolic outfit has been
retained for a proper accomplishment of its function. In contrast, the cells
bordering the sieve element have gained metabolic weight during evolution.
With reference to their evolutionary descent, the peculiarities of sieve
elements and companion cells are discussed in the light of recent
cell-biological and molecular-biological findings. Emphasis is focused on
their interaction, which is the secret of the success of the sieve
element/companion cell complex.
Phloem water relations and root growth
Authors: Pritchard Jeremy , Winch Sam , Gould Nick
Published: September 2002

In this paper the biophysical basis of cell
expansion is described, paying particular attention to the waterrelations that
underpin the process. The connection of growing root cells to the rest of the
plant will be addressed and possible control points in the hardware
identified. Examples of environmental modification of root extension, and
therefore water and solute import, are given, and the relationship with
current accepted theories of solute translocation discussed. The opportunities
for delivery of solutes and water to be regulated by the growing root itself
will be considered, in particular the dual role of cell wall loosening in
decreasing both sink cell turgor and water potential. We conclude that a
significant proportion of the water for cell expansion can enter growing root
cells through the phloem. The physiological data presented rule out
alterations in the turgor pressure difference between sieve element and cell
as a modulator of solute flux. The plasmodesmata are identified as the major
control point of solute flux along the symplastic pathway.
The regulation of assimilate allocation and transport
Authors: Hellmann Hanjo , Barker Laurence , Funck Dietmar , Frommer Wolf B.
Published: September 2002

In higher plants, sugars possess multiplefunctions: transport and storage of carbon and energy as well as signalmolecules. A variety of sugar transporters have been cloned that showdifferential expression between source and sink tissues. Expression of thesetransporters is highly regulated, according to the local metabolic status andthe demands of long distance transport. Very little knowledge is available onmechanisms underlying the regulation of sugar transporter expression inplants. Studies in E. coli, yeast and mammals haveunravelled complex regulatory pathways with crosstalk between sugar transportand metabolism. Recent studies in plants provide increasing evidence for theexistence of similar regulatory mechanisms. In many cases, connections havebeen found between C-and N-metabolism, implicating a tight network of signaltransduction and metabolism. Some aspects of this network are presented inthis review, emphasising sugar transport and sugar signaltransduction.
Localization of a calcium channel-like protein in the sieve element plasma membrane
Authors: Volk Gayle M. , Franceschi Vincent R.
Published: September 2002

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999
There is evidence that calcium (Ca2+) activity in
sieve elements is much higher than in adjacent cells, which raises questions
about Ca2+ exchange across the sieve element plasma
membrane. We looked for the presence of Ca2+
channels in tobacco (Nicotiana tabacum L.) and
Pistia stratiotes (L.) using a monoclonal antibody to a
dihydropyridine (DHP)-type Ca channel (MAB427). Immunolabeling at the light
microscope level gave strong signals along the sieve element of both species,
and with the transmission electron microscope this label was found associated
with the plasma membrane. Western blot analysis using the MAB427 antibody
detects a protein between 175 and 220 kDa (approximately the size expected of
the α-1 subunit of the Ca2+ channel protein
in mammals) in blots containing either Pistia or tobacco
leaf microsomal membrane protein extracts. As a further test for
Ca2+ channels, hand-sectioned young
Pistia leaves were treated with the fluorescent-tagged
Ca2+ channel blocker
4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-3-(indacene)propionic
acid (DM-BODIPY)-DHP. The phloem, as well as calcium oxalate idioblast cells,
exhibited strong fluorescence compared to general parenchyma cells. The
binding of DM-BODIPY-DHP was inhibited by pre-treatment of sections with
nifedipine, a competitive inhibitor of DHP-type
Ca2+ channels in animal systems. The results
indicate that sieve elements may be enriched with
Ca2+ channels which might be partly responsible for
the high Ca2+ activities observed in sieve sap, and
also for rapid phloem responses, such as Ca2+
activated callose deposition.
Nitrogen isotope fractionation in the fodder tree tagasaste (Chamaecytisus proliferus) and assessment of N2 fixation inputs in deep sandy soils of Western Australia
Authors: Unkovich Murray J. , Pate John S. , Lefroy Edward C. , Arthur David J.
Published: September 2002

Nitrogen (N) isotope fractionation and symbiotic N fixation were investigated
in the shrub legume tagasaste, growing in the glasshouse and field. In a pot
study of effectively nodulated plants supplied with 0, 1, 5 and 10 mM nitrate
[stable isotope 15N
(δ15N) of 3.45‰], the
δ15N of dry matter N of fully symbiotic cultures
indicated a greater isotope fractionation during distribution of N between
nodules, stems, leaves and roots than for N2 fixation
itself, with whole-plant δ15N being near zero
(–0.46 to 0.42‰). Regardless of whether plants were field-grown,
pot-cultured, fixing N2 or utilising mineral N, woody
stems were depleted in 15N relative to all other plant
parts. The similar orders of ranking of δ15N for
plant components of the nitrate-treated and fully symbiotic plants, and a
general increase in δ15N as plants were exposed to
increasing concentrations of nitrate, indicated that N isotope fractionation
can be accounted for, and thus not undermine 15N natural
abundance as means of measuring N2 fixation inputs in
tagasaste trees. In pot culture the percentage of plant N derived from the
atmosphere (%Ndfa) by symbiotic N2 fixation fell
from 85 to 37% when the nitrate supply was increased from 1 to 10 mM,
with evidence of nitrate N being preferentially allocated to roots.
δ15N natural abundance assessments of
N2 fixation of 4-year-old trees of field-grown tagasaste
in alley (550 trees ha-1) or plantation (2330 trees
ha-1) spacing were undertaken at a study site at Moora,
Western Australia, over a 2-year period of shoot regrowth (coppicing).
Cumulative N yields and %Ndfa were similar for trees of alley and
plantation spacing, with much less coppice N accumulation in the first
compared to the second year after cutting. Scaling values from a tree to plot
area basis, and using a mean %Ndfa value of 83% for all trees at
the site, inputs of fixed N into current biomass plus fallen litter over the 2
years of coppicing were calculated to be 83 kg N ha-1
year-1 for the alley and 390 kg N
ha-1 year-1 for the plantation
spacing. Although the plantation tagasaste fixed 587 kg N
ha-1 in the second year, close to the maximum value
reported in the literature for any N2-fixing system,
this should not be seen as typical where the trees are used for animal
production, since grazing and cutting management will substantially reduce
productivity and N2 fixation input.
Regulation of water channel activity in whole roots and in protoplasts from roots of melon plants grown under saline conditions
Authors: Martínez-Ballesta Maria del Carmen , Martínez Vicente , Carvajal Micaela
Published: September 2002

Measurements of the hydraulic conductance
(L0) of roots of melon plants
(Cucumis melo L.) derived from roots grown under saline
conditions were performed to determine the effect of NaCl and which ion, Na
+ or Cl – , is
involved. Root hydraulic conductance of plants treated with a 50 mM NaCl, 47
mM Na + or 45 mM Cl –
salts mixture was reduced, but the reduction was less when 10 mM
CaCl2 was added before the salts, except in the case of
the Cl – salt mixture. Only when
CaCl2 was applied before NaCl was there an ameliorative
effect on L0 (25.8%
increase). Addition of HgCl2 reduced
theL0 of control plants, but the
reduction progressively decreased as the NaCl concentration was increased
(from 0 to 50 mM). Osmotic water permeability
(Pf) values were calculated in
root protoplasts treated with 90 mM NaCl. Large reductions were observed with
the NaCl treatment (10.38 mm s –1 for the control
and 3.31 mm s –1 for the NaCl treatment). In
addition, Pfmeasurements were
carried out for protoplasts treated with 100 mM NaCl plus the phosphatase
inhibitor, okadaic acid (5 mM). The effect of okadaic acid on Pf values before
and after NaCl addition was similar (6.61 and 7.01 mm s
–1 , respectively), showing a smaller decrease of
Pf than with NaCl alone with
respect to control protoplasts. The results showed that the negative effect of
NaCl on water channel activity was not due to a high ion concentration effect
on channel pores or to the increase in osmotic pressure. We suggest that it
was due to a direct action of NaCl on protein regulation.
Surrogacy in Australia: implantation rates have implications for embryo quality and uterine receptivity
Authors: Stafford-Bell M. A. , Copeland C. M.
Published: September 2002

Since the passage, in November 1995, of the ACT Substitute Parents Agreement
Act, The Canberra Fertility Centre has added a true gestational carrier
pregnancy programme to its established infertility and IVF services. Embryos
generated are transferred as frozen–thawed embryos to the carrier in an
average of 2.2 embryos per transfer. Between 1 January 1996 and 31 December
1999 the results of 49 frozen embryo transfers to 25 gestational carriers were
compared with 849 frozen embryo transfers on a routine IVF programme. In the
carrier group, the embryo implantation rate of 13.8% per embryo
transferred is double that of an exactly comparable group of patients
undergoing routine frozen–thawed embryo transfer on the same IVF
programme and considerably higher than those reported in large series of
frozen–thawed embryo transfers. Exclusion from the carrier pregnancy
programme of patients with incipient ovarian failure results in an
implantation rate of 16.7%, a clinical pregnancy rate of 29.0%
and a live birth rate of 19.4% per embryo transfer procedure.
Contraceptive effects of levonorgestrel implants in a marsupial
Authors: Nave C. D. , Shaw G. , Short R. V. , Renfree M. B.
Published: September 2002

The effect of subcutaneous levonorgestrel implants on reproduction
in female tammar wallabies was investigated during the breeding and
non-breeding season. Female tammars were given either a control or a
levonorgestrel implant and their pouch young were removed to terminate
embryonic diapause. Both the control and the levonorgestrel-implant animals
treated during the months of May and June gave birth, demonstrating that
levonorgestrel does not prevent the reactivation of the diapausing blastocyst
or its subsequent development when given at these times. However, none of the
levonorgestrel-treated animals mated post partum, whereas all of the control
females that gave birth had a post partum oestrus and mated. Control animals
gave birth again when the neonate was removed, and continued to breed normally
during the following 36 months of the investigation. None of the
levonorgestrel-treated animals gave birth again or mated during the next 36
months. Animals given control implants during December did not reactivate or
give birth until the normal start of the breeding season in late January.
Animals treated with levonorgestrel implants during December did not
reactivate with the control animals at the beginning of the breeding season
and did not give birth during the next 36 months. There were no effects of
lev-onorgestrel treatment on early lactation. Levonorgestrel implants were
removed from six females and four of these animals resumed reproductive
activity, confirming that the contraceptive effect of the implants is
reversible. Levonorgestrel implants therefore provide a highly effective,
reversible and long-term method of contraception for tammar wallabies. This
contraceptive system appears to offer a method of population control for the
management of overabundant captive and selected wild populations of macropodid
marsupials.
Genes involved in implantation
Authors: Salamonsen Lois A. , Nie Guiying , Dimitriadis Eva , Robb Lorraine , Findlay Jock K.
Published: September 2002

The endometrium is normally a hostile environment for an embryo, except for a
short phase in each reproductive cycle known as the ‘window of
receptivity’. The precise molecular events involved in this
transformation are not well understood. Application of state-of-the-art
techniques of the 1990s has identified some of the genes involved, which are
reviewed here. Mice with a null mutation in either the gene for leukemia
inhibitory factor or the interleukin-11 receptor α chain are infertile,
owing in both cases to a failure of embryo implantation. Both of these genes
are expressed in the human endometrium with patterns suggesting a role in
human fertility. The technique of RNA differential display has been applied to
a comparison of the expression of genes at implantation sites v.
inter-implantation sites in the mouse uterus on the first day of implantation,
and has defined additional genes whose products may be important for this
process. Among these are the calcium-binding protein D9K, the monoclonal
non-specific suppressor factor β , and the splicing factor SC35. The major
challenge is to determine whether manipulation of such genes can increase or
decrease endometrial receptivity in humans.
Development of reconstituted pig embryos by nuclear transfer of cultured cumulus cells
Authors: Cheong H. T. , Ikeda K. , Diaz M. A. Martinez , Katagiri S. , Takahashi Y.
Published: September 2002

This study tested the effects of oocyte collection method, activation protocol
and maturational age of recipient oocytes on the
in vitro development of nuclear transfer embryos
reconstructed with cultured cumulus cells. Cumulus cells synchronized in
G0/G1 phase by
serum-starvation culture were transferred into enucleated oocytes that were
collected by aspiration or dissection method and cultured for 33 or 44 h.
Reconstituted embryos were activated with a combination of calcium ionophore
A23187 or electric pulse and cycloheximide (CHXM), and cultured for 6 days.
Oocyte collection methods, activation treatment in the presence of
cytochalasin B and activation protocols did not affect the developmental rate
of embryos reconstituted with 44-h-matured recipients. However, the
development of embryos reconstituted with 33-h-matured recipients was
significantly improved (P<0.05) by activation with
the combination of electric pulse and CHXM. The present study shows that
reconstituted porcine embryos derived from cultured cumulus cells can develop
to the blastocyst stage, and that their development can be improved by
reconstruction with young oocyte cytoplasts following activation with a
combination of electric pulse and CHXM.
The influence of estrogen on the developing male marsupial
Authors: Renfree Marilyn B. , Coveney Douglas , Shaw Geoffrey
Published: September 2002

The genes and hormones involved in gonadal differentiation are highly
conserved between eutherians and marsupials, although the timing of the
developmental events differs. In marsupials, the testis develops seminiferous
cords two days after birth, and the ovaries are not distinguishable until
around eight days after birth. Differentiation of the internal genitalia is
controlled in marsupials, as in eutherians, by testicular testosterone and
MÜllerian inhibiting substance, but differentiation of the scrotum in
males and mammary primordia in females is hormone-independent. Since the young
are easily accessible in the pouch, it is possible to administer gonadal
hormones during the period of sexual differentiation. In both Australian and
South American marsupials, estradiol treatment of neonatal males can induce
male-to-female gonadal sex reversal. The testicular transformations range from
partial suppression of seminiferous tubule development to the development of a
morphologically normal ovary depending on the stage that treatment starts. The
sex-reversed testes have a clearly defined cortex and medulla, and there are
significantly fewer germ cells. The germ cells are surrounded by follicle-like
cells and are in the early stages of meiosis, as is normal for XX germ cells
in ovaries. In normal males, germ cells only enter meiosis at the onset of
puberty. As in eutherians, estrogen treatment of neonatal male marsupials
prevents regression of the MÜllerian ducts, which are hypertrophic.
Neonatal estradiol exposure also causes hypertrophy of the prostate and
urogenital sinus. Estradiol treatment also inhibits transabdominal testicular
descent and many animals develop inguinal hernias. The ability of estradiol to
cause testis-to-ovary sex reversal in marsupials provides a new way of
studying the interactions between genes and hormones in testicular
differentiation.
Extracellular matrix molecules and follicle morphogenesis in ovine skin
Authors: Moore A. G. , Moore G. P. M.
Published: September 2002

Chondroitin sulphate, fibronectin, laminin and the hyaluronan receptor, CD44,
were localized in ovine skin during follicle morphogenesis. Prior to
initiation, chondroitin sulphate was detected in the mesenchyme adjacent to
the dermal–epidermal junction and showed an approximately regular
periodicity in staining intensity. With the appearance of follicle primordia,
the more strongly stained regions of the matrix were associated with
mesenchymal condensations. During later development and in the mature
follicle, staining was localized to the matrices of cells of the dermal sheath
and papilla. CD44 was also localized in the mesenchymal condensations at
follicle initiation and, subsequently, in the dermal sheath. Fibronectin
staining was confined to the mesenchyme prior to follicle formation and became
associated with presumptive papilla and dermal sheath cells during follicle
formation and maturation. Fibronectin antisera detected an approximately 220
kDa protein in western blots of adult and fetal skin. An additional band of
150 kDa was also observed prior to follicle initiation. In contrast, laminin
was predominantly restricted to the basal laminae of developing and mature
follicles. The aggregative behaviour of ovine papilla cells was examined
in vitro. The number and size of aggregates were not
affected by inclusion of chondroitin sulphate or fibronectin in the culture
medium, but both increased in the presence of hyaluronidase. Chondroitinase
had the opposite effect and β-D -xyloside completely abolished
aggregative behaviour. In conclusion, the appearance of certain matrix
molecules may presage morphogenetic movements of cells at follicle initiation
and regulate patterns of follicle distribution in skin during fetal life.
Ovulation in the tree shrew (Tupaia belangeri) induced by gonadotrophins
Authors: Cao Xiaomei , Ben Kunlong , Wang Xiaolei
Published: September 2002

The induction of ovulation by exogenous gonadotrophins is an important
approach for recovering oocytes used for studies on the reproductive biology
of some mammals. In the present study, pregnant mare serum gonadotrophin
(PMSG) and human chorionic gonadotrophin (hCG) were used to induce ovulation
in the tree shrew (Tupaia belangeri) using the following
regimens. Groups A1–A3, multiple injections of PMSG (30–60 IU)
followed by a single dose of hCG (30–60 IU); B1, combination of a single
injection of PMSG (60 IU) with a single dose of hCG (60 IU); E1, combination
of a single injection of PMSG (60 IU) with a single dose of hCG (30 IU) plus
PMSG (30 IU); and administration of either PMSG (C1 and C2) or hCG (D1). The
ovulation rate of animals producing oocytes with either first polar body or
distinct perivitelline space, and the mean number of oocytes per animal were
considered the most important criteria in each regimen. The most effective
induction of ovulation was achieved in groups B1 and E1, with ovulation rates
of 4/4 and 4/4, respectively, and mean numbers of ovulated oocytes per
animal of 3.25 0.48 and 4.00 0.71 respectively. No ovulation was observed in
the control group or in group D1. Therefore, regimes B1 and E1 were considered
as the simplest and most effective for the induction of ovulation in the tree
shrew.
Modelling reproduction in farm animals: a review
Authors: Blanc Fabienne , Martin Graeme B. , Bocquier François
Published: September 2002

During the last few decades, our knowledge of the biology of the reproductive
system has improved significantly and also become more quantitative. In
parallel, there has been an increase in the development of mathematical
models, as both research tools and management tools, that can integrate our
knowledge of reproductive events and then attempt to predict reproductive
efficiency. This review considers these modelling approaches according to the
level of organization that they address, from representation of the dynamic
functions of the reproductive axis to the prediction of reproductive
performance of a flock or herd. We emphasize the contribution of modelling to
the exploration and understanding of a complex system—a system that
responds to a host of internal regulatory mechanisms as well as to an array of
external factors such as nutrition, photoperiod and sociosexual signals. To
date, models have proven useful for depicting the kinetics of some of the
endocrine signals that are implicated in perturbations of the reproductive
axis and they have also been successful in the exploration of ovarian dynamics
during the oestrous cycle. However, two areas are still largely unexplored by
biomathematical models: the dynamic links between the different stages of the
reproductive life of an animal, and mechanistic influences of environmental
factors on the reproductive axis.
Persistence of pregnant mare serum gonadotrophin in plasma of Japanese quail (Coturnix coturnix japonica)
Authors: Girling J. E. , Bennett E. J. , Henderson K. M. , Cockrem J.
Published: September 2002

Pregnant mare serum gonadotrophin (PMSG) is currently being used to develop a hormone regime that will stimulate reproductive development in Japanese quail (Coturnix coturnix japonica). In this study, the persistence of PMSG in quail plasma was examined after a single injection of the hormone (500 IU). Plasma concentrations of PMSG increased to a peak 12 h after injection and declined to approximately 50% of peak concentrations 24 h after injection. Pregnant mare serum gonadotrophin concentrations declined gradually thereafter and had not returned to basal levels by 96 h after injection. Cloacal diameter, and ovarian and oviducal mass, had increased significantly by 96 h after injection. The persistence of PMSG in quail plasma has implications for the use of the hormone in future regimes stimulating reproductive activity in birds.
Pachyderms, primates, plants and population
Authors: Campbell Martha M.
Published: September 2002

In the past, growth in human population has often been associated with species
loss. Current rates of population growth, both globally (1 million more births
than deaths every 103 hours) and regionally, pose a threat of additional
ecological damage. There is a well-documented unmet demand for family planning
in nearly all high-fertility countries. Improved family planning and safe
abortion services will improve the health of women and their families,
accelerate fertility decline, and help preserve the environment. Many
ecologically vulnerable areas are especially poorly served by family planning
services. Examples are given here of improving family planning services
through private health providers near the Kakamega Forest in western Kenya,
and of adding family planning choices to a reforestation project run by the
Jane Goodall Institute near the Gombe National Park, Tanzania. Wildlife
biologists can play a critical role in identifying local professionals and
institutions with the potential to improve family planning.
Saving the gorillas (Gorilla g. gorilla) and chimpanzees (Pan t. troglodytes) of the Congo Basin
Authors: Tutin Caroline E. G.
Published: September 2002

The forests of the Congo Basin in equatorial Africa are home to significant
populations of gorillas and chimpanzees. However, numbers are declining owing
to hunting and to alteration of their habitat. Gorillas and chimpanzees are
particularly vulnerable for biological reasons: slow reproduction, prolonged
developmental periods and complex social behaviour. In addition, their
capacity to recover from disturbance is limited and the reinforcement of wild
populations with captive-born individuals is rarely an option. Compared with
the critically endangered mountain gorillas and the beleaguered chimpanzees in
forest fragments in West Africa, there are some reasons for optimism about the
future of the Congo Basin apes: levels of threat remain relatively low; and
conservation of tropical rainforests has become a priority of the
international community. At the same time, knowledge of the ecological needs
of wild apes has increased and non-invasive techniques now exist to monitor
population health. Sadly, no animals remain truly ‘wild’, as their
survival depends to a greater or lesser extent on management. Protected areas
and laws that forbid hunting of vulnerable species are classic tools of
management, but broader landscape visions are now emerging that may allow the
Congo Basin to avoid the fragile scenario of larger animals persisting only in
‘island’ parks.
Farmed deer: new domestic animals defined by controlled breeding
Authors: Fletcher T. J.
Published: September 2002

The domestication of plants and animals is recognized as pivotal in
mankind’s social evolution. Yet, surprisingly few species have actually
been farmed, prompting speculation as to which attributes are needed for
successful domestication. Although red deer were the staple source of meat
throughout Europe in the mesolithic, they have not been widely domesticated,
leading many ethologists to argue that they are behaviourally unsuitable.
Recently, the most widely accepted criterion of domestication, the ability of
farmers to control the breeding of a species, has been fulfilled in red and
other species of deer with the widespread adoption of even the most
technologically advanced methods of artificial breeding. Simultaneously and
conversely, the population growth of wild deer in many temperate parts of the
world has stimulated a search for contraceptive techniques.
Introduction and expression of foreign genes in cultured mouse embryonic gonads by electroporation
Authors: Nakamura Yuri , Yamamoto Miwako , Matsui Yasuhisa
Published: September 2002

To analyse the functions of genes that are expressed and potentially involved in the development of embryonic gonad cells, a method was developed by which foreign genes can be introduced and expressed in cultured mouse genital ridges. Genital ridges from mouse embryos at 12.5 days post coitus (dpc) were injected with plasmid DNA of a green fluorescence protein (GFP) gene construct and then placed between small electrodes. Rectangular pulses were charged to electroporate DNA into the cells. The treated genital ridges were cultured on a membrane of a culture insert, and GFP gene expression was observed under a fluorescence microscope. Green fluorescence protein expression in the genital ridges was found as early as 1 h after electroporation. Thereafter, the expression gradually increased, peaked after 1 day, and then decreased. A significant number of cells were, however, still positive for fluorescence even after 2 weeks in the culture, in which both gonads and germ cells had continued to develop. The GFP gene was expressed in 1–2% of cells in each genital ridge in a DNA concentration-dependent manner. In addition, we confirmed that an electroporated red fluorescent protein (DsRed) gene construct was expressed in GFP-expressing primordial germ cells in genital ridges of Oct-4/GFP transgenic embryos, although the DNA was mainly found in somatic cells in genital ridges. Finally, an expression vector containing the internal ribosome entry site–green fluorescent protein (IRES-GFP) gene was constructed. An inserted lacZ gene showed similar expression pattern to that of GFP. Using this vector, we can easily monitor the expression of an inserted gene of interest by GFP expression. Therefore, this experimental system could be useful for quick assays of gene function in genital ridges.
Boar semen controlled-delivery system: morphological investigation and in vitro fertilization test
Authors: Vigo Daniele , Faustini Massimo , Torre Maria Luisa , Pecile Alessandro , Villani Simona , Asti Annalia , Norberti Roberta , Maggi Lauretta , Conte Ubaldo , Cremonesi Fausto , Stacchezzini Simona , Maffeo Giovanni
Published: September 2002

A technology for encapsulation of swine semen in barium alginate and protamine alginate has recently been proposed for the controlled release of the spermatozoa, thus reducing the number of instrumental inseminations required. Controlled-release capsules containing swine spermatozoa were prepared by adding saturated BaCl2 solution to ejaculate and dropping the resulting suspension into a sodium alginate solution, leading to the formation of barium alginate capsules. A second type of capsule was obtained by cross-linking the barium alginate with protamine sulfate. Two types of membrane were thus obtained: barium alginate gel and a protamine cross-linked alginate membrane. Morphological (scanning electron microscopy and transmission electron microscopy), functional (motility, membrane integrity and in vitro fertilization test) and technological (capsule structure and weight) approaches were used to characterize the encapsulated spermatozoa and the controlled-delivery system. No differences in terms of morphological and functional characteristics (acrosome integrity and spermatozoa motility) between free and encapsulated semen were found. The technological process did not compromise in vitro fertilization potency of the spermatazoa, although seasonal variability was found. The capsule weight was related to either the pH of the semen or the season. This study represents the starting point for the development of further investigations into the storage and release kinetics of cells from the capsules and for the development of an in vivo fertilization protocol.
The Australian zygomycetous mycorrhizal fungi. II. Further Australian sporocarpic Glomaceae
Authors: McGee Peter A. , Trappe James M.
Published: September 2002

Glomus atrouva, G. canum,
G. cuneatum and G. pellucidum sp.
nov. are described from eastern New South Wales. New distributional data and
redescriptions are presented for G. australe,
G. fuegianum, G. fulvum and
G. pubescens, the last three being first reports for
Australia. New records of
G. caledonium,G. macrocarpum and
G. tenerum are also included.
An investigation of genetic variation in Banksia integrifolia (Proteaceae) by the use of the AFLP technique
Authors: Evans Katharine M. , Newbigin Ed , Ladiges Pauline Y.
Published: September 2002

The Banksia integrifolia L.f. species complex has
undergone several taxonomic treatments over the past 20 years. In order to
gain further insight into phenetic relationships between the taxa of this
species, the distribution of genetic variation over the geographic range of
B. integrifolia was investigated by the amplified
fragment length polymorphism (AFLP) technique. Ordination and classification
analyses resulted in clusters of individuals that closely conformed to the
different taxa of this species. Further ordination and classification analyses
of individuals of just B. integrifolia subsp.
integrifolia indicate that there are also geographical
patterns within the subspecies, with those individuals from the north of the
species’ range clustering away from those in the south of the range. A
Mantel-test between morphological data collected in a previous study and
molecular data collected in this study indicated a highly significant
correlation between morphological and genetic variation. This study thus
supports the current taxonomic classification of the
B. integrifolia species complex.
Threats to the survival of the Grampians pincushion lily (Borya mirabillis, Lilliaceae) —a short-range endemic from western Victoria
Authors: Coates Fiona , Walsh Neville G. , James Elizabeth A.
Published: September 2002

The Grampians pincushion lily (Borya mirabilis Churchill) is a resurrection plant confined to one population at a single rock outcrop in western Victoria. It is a taxonomically well-defined species and geographically widely separated from its most closely related congeners in the south-west of Western Australia. Monitoring over a 12-month period showed a significant decline in population condition that was associated with soil disturbance and damage to associated vegetation. Although able to reproduce vegetatively, B. mirabilis is not known to produce viable seed. Molecular work revealed that all plants in the population were likely to be genetically identical. Investigation of the breeding system showed that pollen viability was low and pollen tube growth was possibly insufficient to fertilise ovules. One explanation for lack of effective sexual reproduction is the presence of a mechanism for self-incompatibility. The decline in population condition and lack of ramet establishment at present are predominantly a result of high levels of ground disturbance from pest animals. Without active and immediate site management the population is likely to become extinct under current circumstances.
A phylogenetic analysis of the Chamelaucium alliance (Myrtaceae)
Authors: Lam N. , Wilson P. G. , Heslewood M. M. , Quinn C. J.
Published: September 2002

Analysis of sequence data from the matK gene and the atpβrbcL intergenic spacer for 70 representatives of the Chamelaucium alliance sensu Briggs and Johnson (1979) provides strong support for the monophyly of the alliance, but there is no support for their concept of suballiances on the basis of fruit type: indehiscent fruit have arisen in multiple lineages. There is, however, strong support for Calytrix, Homalocalyx and Ochrosperma being the first lineages to diverge within the alliance. A number of genera within the alliance are not monophyletic in this analysis, namely Astartea, Babingtonia, Baeckea sensu lato, Darwinia and Hypocalymma. Monophyly of Baeckea sensu stricto, Euryomyrtus, Ochrosperma, Rinzia, Scholtzia and Triplarina is strongly supported. Several well-supported groups that may warrant generic status have been identified.
A new classification of the genus Eucalyptus L'Hér. (Myrtaceae)
Authors: Brooker M. I. H.
Published: September 2002

A new formal classification of the genus Eucalyptus is presented. It divides the genus into seven polytypic subgenera: E. subg. Angophora, E. subg. Corymbia, E. subg. Blakella, E. subg. Eudesmia, E . subg. Symphyomyrtus, E. subg. Minutifructa and E. subg. Eucalyptus, and six monotypic subgenera: E. subg. Acerosa, E. subg. Cruciformes, E. subg. Alveolata, E. subg. Cuboidea, E. subg. Idiogenes and E. subg. Primitiva. The system is intentionally phylogenetic, proceeding from the generally assumed primitive ‘apples’ (E. subg. Angophora) and bloodwoods (E. subg. Corymbia) to the most advanced and modified group, the monocalypts (E. subg. Eucalyptus). The genus Corymbia Hill & Johnson is subsumed under Eucalyptus and is represented by E. subg. Corymbia (the bloodwoods) and E. subg. Blakella (the ghostgums).New infrageneric taxa are diagnosed and their names typified, while brief digests in English are given for established taxa. Three species of the former genus Angophora have names with epithets preoccupied by names of other Eucalyptus species and new names are presented for them. The study is introduced by a brief historical summary of previous work in Eucalyptus, an apologia for the inclusion of Angophora, the reason for requirement of a new classification and notes on the nomenclature used. A new infrageneric rank, ‘supraspecies’, is introduced and is intentionally divorced in application (as a rank) from the similar sounding ‘superspecies’. All species recognised by the author are named and assigned in this system.
Explaining groundwater hydrographs: separating atypical rainfall events from time trends
Authors: Ferdowsian Ruhi , Pannell David J. , McCarron Clare , Ryder Arjen , Crossing Lisa
Published: September 2002

By 1994, an estimated 1.8 million hectares of cleared land in Western
Australia was affected by secondary dryland salinity to some extent. The area
affected is likely to double in the coming 20 years. The cause of this
salinity is excessive recharge under traditional agriculture, leading to
rising groundwater levels. Monitoring changes in groundwater levels is helpful
in indicating the degree of threat to agricultural land and public assets.
Many researchers have studied groundwater level rises and attempted to explain
them statistically.
We present an approach for statistically estimating trends in groundwater
levels. The approach separates the effect of atypical rainfall events from the
underlying time trend and the lag between rainfall and its impact on
groundwater is explicitly represented. Rainfall is represented as an
accumulation of deviations from average rainfall. Application of the approach
is demonstrated using data from 49 bores in Jerramungup Shire, Western
Australia. The approach provides high explanatory power, particularly for
deeper bores.
Fractionation of cobalt and manganese in New Zealand soils
Authors: Li Z. , McLaren R. G. , Metherell A. K.
Published: September 2002

Many New Zealand soils are known to produce pastures deficient in cobalt (Co)
for grazing ruminants; however, the development of an effective soil
diagnostic test for Co is hindered by the lack of knowledge of the forms and
distribution of Co in New Zealand soils. A sequential fractionation technique
was used to determine the forms and concentrations of native and/or
fertiliser derived soil Co in 18 New Zealand grassland topsoils, and the
distribution and interrelationships of Co between fractions compared with
those for manganese (Mn). Previous studies in other countries have indicated a
strong association between Co and Mn in soils. For both Co and Mn, very small
proportions were present in soluble and exchangeable forms, and the highest
proportions of Co and Mn (mean 45.8% and 35.8%,
respectively) were found in the residual fraction. However, there was little
similarity overall in the distribution of Co and Mn between fractions.
Multiple regression models, and the presence of substantial amounts of Co and
Mn in iron (Fe) oxide fractions, indicate that the Fe content of the soil is
much more important than Mn in influencing the distribution of Co in the
soils. Exchangeable Co and Mn also appear highly sensitive to soil pH. Soil
organic matter did not appear to have a major effect on the distribution of Co
in soils, apart from Pumice Soils that have low concentrations of Fe and Mn.
Effects of electrolyte composition on chromium desorption in soils contaminated by tannery waste
Authors: Avudainayagam S. , Naidu R. , Kookana R. S. , Alston A. M. , McClure S. , Smith L. H.
Published: September 2002

We conducted batch studies to investigate the effect of phosphate and dominant
cations present in tannery waste on desorption of chromium (Cr) from surface
and subsurface soil horizons from a contaminated tannery waste site at Mount
Barker, South Australia. The surface horizon (0–15 cm) of the soil
profile was alkaline (pH 7.9) and the subsurface horizon (50–90 cm) was
acidic (pH 3.9). Aqua-regia extractable Cr concentration ranged from 62
g/kg in the surface to 0.26 g/kg in the subsurface soils. X-ray
diffraction and scanning electron microscopic studies revealed the
predominance of carbonate and kaolin minerals in the surface soils, and highly
weathered framboidal particles, with morphology similar to that of pyrites, in
the subsurface soils. The amount of Cr desorbed from the contaminated soils
varied considerably with both the electrolyte’s cationic charge and soil
properties. The effect of cations, Ca 2+ and Na
+ (CaCl 2 , NaCl), and
phosphate on desorption of Cr was investigated. While the ionic strength of
the solutions was standardised at approximately 0.03 mol/L, the
concentration of phosphate (as KH 2 PO
4) was varied from 0 to 3.2 mmol/L. On the basis of
studies on solution to soil ratio and desorption kinetics we chose a 20: 1
solution to soil ratio and 2 h equilibration time. In the surface alkaline
soil, the amount of Cr released decreased in the order Na
+ (286 μg/L) ≥ water (256
μg/L) > Ca 2+ (156
μg/L). In contrast subsurface acidic soil showed a reverse trend,
i.e. Ca 2+ (52 μg/L) > Na
+ (29 μg/L) > water (20
μg/ L). Speciation of Cr in the extracts showed predominantly
Cr(VI) in the alkaline surface soil and Cr(III) in the subsurface acidic soil.
A strong effect of phosphate on the cumulative amount of chromate desorbed was
observed. The study shows that the presence of high concentrations of Na
+ (0.03 mol/L) and phosphate (3.2 mmol/L)
in soil solution enhances Cr(VI) mobility. In contrast, Ca
2+ may induce retention of Cr(VI) in
Cr-contaminated alkaline soils.