bluuebunny/crossref_metadata_2025 huggingface dataset:
Reproductive ecology and breeding system of Lomatia silaifolia (Proteaceae) following a fire
Authors: Denham Andrew J. , Whelan Robert J.
Published: September 2002

Lomatia silaifolia (Smith) R.Br. (Proteaceae) is a
common shrub in southeastern Australian bushland that generally flowers only
once after each fire. However, little is known of the details of this
post-fire flowering. Lomatia silaifolia has flowers
well-spaced along its conflorescence axis, unlike many other Proteaceae
species, thus allowing close examination of the influence of flower position,
mate choice and flowering sequence on fruit production. We examined breeding
system, flowering phenology and spatial patterns of fruit set in the species,
after a fire in September 1992 at Bulli Tops, New South Wales. Flowering
occurred in December–January, but only in the first and second summers
after the fire. The species is partially self-compatible: only 25% of
self-pollinated conflorescences initiated fruits compared with 100% of
cross-pollinated conflorescences. Fewer flowers initiated fruits after hand
self-pollination (3.0%) than after cross-pollination (35.4%).
Self-pollinated flowers produced fewer viable seeds (22.2% viable) than
cross-pollinated flowers (62.9% viable). Pollen tubes were found in
72% of the self-pollinated flowers examined, suggesting that there is
no early stylar self-incompatibility in the species. There was a high level of
herbivory on flowering and fruiting branches, with 69% of unbagged
branches completely destroyed. This may significantly affect recruitment in
the species, given the limited opportunities for reproduction in the post-fire
environment. In this study, fruits were evenly distributed along the
conflorescence axis unlike some other species in the Proteaceae with more
compressed, spike-like flowering structures where fruits are typically
concentrated in some parts of the conflorescence axis (e.g.
Telopea and some Banksia spp.). No
bird visitors to flowers were observed, but a variety of insect visitors were
identified.
Achieving practical outcomes from genetic studies of rare Australian plants
Authors: Hogbin Patricia M. , Peakall Rod , Sydes Marita A.
Published: September 2002

An increasing number of genetic studies of rare plants are motivated by the
potential contribution they can make to the conservation of the species
concerned. However, while these studies frequently identify conservation
implications, few have demonstrated practical conservation outcomes. In this
paper, we criticallyevaluate the practical outcomes of our genetic study of
three endangered plant species: Haloragodendron lucasii,
Zieria prostrata and
Wollemia nobilis. Each genetic study provided a number
of conservation implications or management recommendations for the species
concerned. However, for three reasons, not all of the implications actually
led to practical outcomes. First, similar recommendations were already in
place. Second, management recommendations, while sound, were not relevant to
the current management priorities. Third, irrespective of the genetic outcome,
a given recommendation prevailed as the preferred management option. In order
to achieve effective and cost-efficient recovery of threatened flora, we need
to identify those cases where genetic studies are likely to produce practical
outcomes for conservation management. This may best be achieved by first,
assessing and critically evaluating the outcomes of genetic research already
conducted, and second, evaluating the potential for practical outcomes of
future research by considering the range of possible outcomes in the context
of the management options available for the species.
Defining conservation units in a rich and fragmented flora: implications for the management of genetic resources and evolutionary processes in south-west Australian plants
Authors: Coates David J.
Published: September 2002

The south-west Australian flora shows a diverse array of evolutionary patterns
and exceptionally high species diversity. A significant component of this
flora consists of relictual species which often have naturally fragmented and
geographically restricted distributions. Many of these species appear to
apportion significant levels of genetic diversity among populations. Diversity
at both the population and species level presents a major challenge to the
development of appropriate conservation strategies for this flora. To be
effective these strategies should not only aim to preserve current levels of
species diversity, but also consider intraspecific variation and the
evolutionary and ecological processes associated with the generation and
maintenance of that variation. The identification and characterisation of
conservation units, based on population genetic structure and phylogeographic
patterns within species, provide a useful basis upon which more general
conservation principals can be developed for the maintenance of these
processes. Population genetic structure and phylogeographic studies are used
to show how conservation units can be identified in
Lambertia orbifolia,
Acacia anomala,
Stylidium coroniforme,
Stylidium nungarinense and
Banksia cuneata, and taxa from a range of other genera.
Determining conservation units in these taxa defines not only suitable units
for their conservation but also the appropriate geographical scale for
management. These findings indicate the potential this approach can have in
determining strategies and priorities for the conservation of the south-west
Australian flora.
Additions to the host range of Phytophthora cinnamomi in the jarrah (Eucalyptus marginata) forest of Western Australia
Authors: McDougall K. L. , Hardy G. E. St J. , Hobbs R. J.
Published: September 2002

Pathogenicity tests with Phytophthora cinnamomi were
conducted on 25 perennial species from the jarrah
(Eucalyptus marginata) forest of Western Australia. Most
species tested had been found in a separate study to be scarce on sites
affected by Phytophthora cinnamomi but frequently found
in unaffected vegetation. Some species that were known to be field-tolerant of
P. cinnamomi and some that were highly susceptible to
infection were included in the study for comparison.
Phytophthora cinnamomi was recorded from 13 of 17
species not previously known to be susceptible.
Phytophthora cinnamomi was subsequently isolated from
dead plants of two of these 13 species in the field. The interpretation of
results from the glasshouse trials was difficult for some species because of
inconsistent patterns of death and P. cinnamomi
isolation in the glasshouse trials.
Phytophthora cinnamomi probably causes decline in wild
populations of Stylidium amoenum, based on the ease of
field and glasshouse isolation of P. cinnamomi and the
scarcity of this forb on dieback sites. It may also contribute to decline in
populations of Boronia fastigiata,
Hybanthus floribundus,
Labichea punctata,
Scaevola calliptera and
Stylidium junceum, although further field sampling is
required to confirm this.
Cryopreservation of Anigozanthos viridis ssp. viridis and related taxa from the south-west of Western Australia
Authors: Turner S. R. , Touchell D. H. , Dixon K. W. , Tan B.
Published: September 2002

Cryostorage of shoot apices of the perennial monocotyledonous species
Anigozanthos viridis Endl. ssp.
viridis (Haemodoraceae) was investigated by using a
modified vitrification protocol. The highest post-thaw survival of shoot
apices (41.4%) involved preculturing shoot apices on 0.4 M sorbitol for
48 h followed by incubation in a vitrification cryoprotective solution (PVS2)
for 25 min at 0˚C. The level and type of cytokinin used in the culture
stage was also found to influence cryostorage success with post-thaw survival
decreasing from 41% with zero to low levels of cytokinins to below
5% for cytokinin levels that are typical of plant tissue applications
(2.5 ˜M) for Australian plant species. Five Haemodoraceae taxa
(Anigozanthos Labill. spp. and
Conostylis R.Br. spp.) were successfully cryopreserved
with this modified protocol; however, a sixth taxon,
Macropidia fuliginosa (Hook.) Druce., remained
unresponsive to this vitrification technique.
Compounds of the 16-Membered Macrocyclic Tetraamine (4RS,12RS)-2,2,4,10,10,12-Hexamethyl-1,5,9,13-tetraaza-cyclohexadecane with Cobalt(II), Nickel(II), Copper(II) and Zinc(II); Structural and Molecular Mechanics Studies
Authors: Curtis Neil F. , Gladkikh Olga P.
Published: September 2002

The cyclic tetraamine compound (4RS,12RS)-(2,2,4,10,10,12-hexamethyl-1,5,9,13-tetraazacyclohexadecane) nickel(II) perchlorate, [Ni(L1 )] (ClO4)2, has been prepared by reduction of the imine functions of (2,4,4,10,12,12-hexamethyl-1,5,9,13-tetraazacyclohexadeca-1,9-diene)nickel(II) by catalytic hydrogenation, or by NaBH4 in acetonitrile/methanol. The ligand L 1 was isolated, after reaction with acid, as the salt [(L 1 )H4](ClO4)Cl3·H2O. Compounds with cobalt(II), copper(II), and zinc(II) were prepared from this, and the structures of [M(L 1 )] (ClO4)2, M = Co, Ni and Cu, and [Cu(L 1 )] [ZnCl4], determined by X-ray diffraction: [Co(C18H40N4)] (ClO4)2, orthorhombic, Pn21/a, a 8.644(3), b 14.869(8), c 19.541(7) Å, Z 4, R1 0.062 for 99 reflections with I > 2s(I); [Ni(C18H40N4)] (ClO4)2, monoclinic, C2/c, a 11.780(4), b 12.580(4), c 16.930(3) Å, b 90.14(4)˚, Z 4, R1 0.067 for 1644 reflections with I > 2s(I); [Cu(C18H40N4)] (ClO4)2, monoclinic, C2/c, a 11.508(7), b 13.17(2), c 16.83(1) Å, b 92.37(5)˚, Z 4, R1 0.114 for 2366 reflections with I > 2s(I); [Cu(C18H40N4)] [ZnCl4], monoclinic, P21/n, a 9.392(3), b 14.915(6), c 17.591(7) Å, b 95.94(3)˚, Z 4, R1 0.041 for 2301 reflections with I > 2s(I). All have the C-rac, 1RS,4SR,5RS,9RS,12RS,13SR, configuration with N–H groups alternating on opposite sides of the molecular ‘plane’ around the ring. All have flattened tetrahedral coordination geometry, with the quartet ground state cobalt(II) cation most twisted and the copper(II) tetrachlorozincate, perchlorate and singlet ground state nickel(II) complex cations progressively more flattened. The macrocycles have overall saddle-like conformations with chelate rings tilted alternately to opposite sides of the molecular ‘plane’. The compounds all have both trimethyl-substituted chelate rings in chair conformations. The unsubstituted chelate rings both have chair conformations for the cobalt(II) compound, both have twist-boat conformations for the nickel(II) and copper(II) perchlorate salts and have one chair and one twist-boat conformation for the copper(II) tetrachlorozincate salt. Mean M–N distances (Å) and trans-N–M–N angles {N(1)–M–N(9), N(5)–M–N(13) (degrees)} are: Co, 1.99, 130.3(5), 115.5(5); Ni, 1.93, 163.6(4), 155.8(4); Cu (ClO4), 1.99, 155.0(6), 143.8(7); Cu (ZnCl4) 2.00, 146.6(2), 135.0(2). The influence of axial interactions with counter ions, hydrogen bonding and other lattice interactions on the structures adopted are discussed. Strain energies for the possible configurations/conformations of coordinated L 1 have been calculated by molecular mechanics and related to the observed structures.
New DNA Modification Strategies Involving Oxime Formation
Authors: Cebon Ben , Lambert John N. , Leung Donmienne , Mackie Hugh , McCluskey Karen L. , Nguyen Xuan , Tassone Claudia
Published: September 2002

A new method for the formation of covalently linked DNA conjugates is
described. The method involves installation of a 5´-hydroxylamine
nucleophile onto synthetic DNA and condensation with a suitable electrophilic
carbonyl compound to form an oxime linkage. Various protection strategies for
the hydroxylamine group and their merits are discussed and the formation of an
oligonucleotide–peptide conjugate is described.
Reaction of Terminally Alkyl-Substituted Oxy Dienes with Tetracyanoethylene and Other Acceptors
Authors: Cameron Donald W. , Heisey Ross M.
Published: September 2002

The 4,4-dimethyl-substituted oxy dienes (4), (19) and (20) did not undergo
cycloaddition to 1,4-quinonoid dienophiles, for steric reasons, but all
reacted with tetracyanoethylene to give [4+2]- or
[2+2]-adducts. Unlike the 1-oxy diene (4), the 2- and 3-oxy
systems (19) and (20) did not show hydrogen-transfer chemistry towards
quinones. The individual components of isomeric pairs of dienes (8), (9) and
(19), (21) were differentiated by differing reactivity towards cycloaddition.
2-Hydroxy-4-oxohenicosan-1-yl Acetate. Its Presence in Avocado and its Simple Chemistry
Authors: Carman Raymond M. , Duffield Alan R. , Handley Paul N. , Karoli Tomislav
Published: September 2002

The title compound (1b) is present in avocado leaves. Simple chemistry of the
compound is described.
The NARC-Based Approach to the Enantioselective Synthesis of the Zaragozic Acids. Synthesis of a C 5-Alkoxycarbonyl-Substituted 2,8-Dioxabicyclo[3.2.1]octane.
Authors: Perlmutter Patrick , Selajarern Walailak
Published: September 2002

A direct method for the preparation of C 5-alkoxycarbonyl-substituted
2,8-dioxabicyclo[3.2.1]octanes is described. The key process
involves a highly stereoselective (NARC) sequence of a nucleophilic addition
followed by ring closure.
Donald W. Cameron
Authors: Cameron Jenny M.
Published: September 2002

A direct method for the preparation of C 5-alkoxycarbonyl-substituted
2,8-dioxabicyclo[3.2.1]octanes is described. The key process
involves a highly stereoselective (NARC) sequence of a nucleophilic addition
followed by ring closure.
The Modulated Crystal Structure of the Molecular Adduct of 2,4,6-Trinitrobenzoic Acid with 2,6-Diaminopyridine
Authors: Smith Graham , Bott Raymond C. , Rae A. David , Willis Anthony C.
Published: September 2002

The 1 : 1 adduct of 2,4,6-trinitrobenzoic acid (tnba) with 2,6-diaminopyridine
(2,6-dap),
[(2,6-dap)+(tnba)-],
has been prepared and the low-temperature crystal structure has been
determined by X-ray crystallography. A modulated structure has been identified
and refined by using a stacking fault model that requires reflection data to
be put on three scales depending on an index condition. Crystals are
triclinic, space group P1–, with Z 8 in a cell of
dimensions a 13.538(3), b
14.516(4), c 16.480(4) Å; α 97.17(2), β
105.69(2), γ 106.09(2)˚. The structure involves proton transfer from
the tnba molecule to the 2,6-dap molecule, with the resulting pyridinium
proton and an amine proton interacting with the carboxyl oxygens of the tnba
molecule in a primary cyclic hydrogen-bonding association. Additional
peripheral hydrogen bonding completes a two-dimensional sheet structure.
Electronic and Structural Properties of the Spin Crossover Systems Bis(2,6-bis(pyrazol-3-yl)pyridine)iron(II) Thiocyanate and Selenocyanate
Authors: Sugiyarto Kristian H. , Scudder Marcia L. , Craig Donald C. , Goodwin Harold A.
Published: September 2002

Essentially high-spin
[Fe(bpp)2][NCS]2·2H2O
and [Fe(bpp)2][NCSe]2 (bpp =
2,6-bis(pyrazol-3-yl)pyridine) were isolated from an aqueous reaction mixture.
Both salts undergo an abrupt transition to low spin below room temperature,
that for the thiocyanate occurring in two steps and the high-spin Æ
low-spin Æ high-spin cycle being accompanied by hysteresis in both
steps. Recrystallization of the salts from nitromethane yielded a mixture from
which bright yellow crystals were separated for structure determination. In
addition, from the recrystallized selenocyanate, deep red-brown crystals of
composition
[Fe(bpp)2][NCSe]2·H2O·0.25
CH3NO2 were obtained.
Recrystallized
[Fe(bpp)2][NCS]2·2H2O
and
[Fe(bpp)2][NCSe]2
were identified as high spin with average Fe–N distances of 2.16 and
2.17 Å, respectively. In the unit cell of
[Fe(bpp)2][NCSe]2·H2O·0.25
CH3NO2, there are four independent
iron atoms, three identified as low spin and the fourth as high spin. All
salts crystallize in a layer-type array involving edge-to-face and
face-to-face aryl–aryl-type interactions. Hydrogen bonding between
pyrazole >NH groups, anions and solvate molecules is observed. The
structure of the uncoordinated ligand was also determined, the molecule being
found in a planar arrangement with
thecis–cis configuration for
the pyrazolyl groups relative to the central pyridyl and the >NH group
being at the N 2 atom. Hydrogen bonding involving the >NH groups leads to
stepped stacks of molecules. The principal difference in the geometry of
coordinated and free bpp molecules is a contraction in the angles about the
interannular bridges in the chelate rings.
[Fe(bpp)2][NCS]2·2H2O:
triclinic, space group P1–,
a 8.302(6), b 8.446(6),
c 21.531(13) Å, a 78.78(5), b 82.80(5), g
89.85(4)˚, Z 2.
[Fe(bpp)2][NCSe]2:
triclinic, space group P1–,
a 8.354(4), b 8.409(4),
c 19.918(9) Å, a 87.02(3), b 83.15(3), g
88.86(3)˚, Z 2.
[Fe(bpp)2][NCSe]2·H2O·0.25
CH3NO2: monoclinic, space group
Pn, a 16.425(12),
b 20.774(9), c 16.933(14) Å,
b 90.91(4)˚, Z 8. Uncoordinated bpp: orthorhombic,
space group Pna21,
a 8.075(3), b 22.479(9),
c 5.525(1) Å, b Z 4.
Chemistry of New Zealand Apiaceae: New irregular diterpenes from Anisotome flexuosa and A. haastii showing conformational exchange
Authors: van Klink John W. , Barlow Anna J. , Benn Michael H. , Perry Nigel B. , Weavers Rex T.
Published: September 2002

Two new derivatives of a recently-reported class of irregular diterpene have
been discovered in New Zealand species of the Apiaceae family.
16-Acetoxyanisotomenoic acid (8)
(3,3a,4,4-tetramethyl-3-{(Z)-5-acetoxy-4-methyl-3-pentenyl}-2,3,3a,4,5,6-hexahydro-1H-2-indenecarboxylic
acid) and anisotomene-1,12-diol (11)
(3,3a,4,4-tetramethyl-3-(2-hydroxy-4-methyl-3-pentenyl)-2,3,3a,4,5,6-hexahydro-1H-2-indenyl)
methanol) have been obtained from the sub-alpine plants,
Anisotome flexuosa and A. haastii
respectively. 13 C nuclear magnetic esonance (n.m.r.)
spectra of the anisotomene derivatives are complicated by line broadening.
Molecular modelling of anisotomenoic acid (1) and anisotomenol (2) suggests
that this is due to conformational exchange in the highly substituted bicyclo
[4,3,0] non-1-ene ring system.
A New Chloro-Depside from the Lichen Hypotrachyna leiophylla
Authors: Elix John A. , Wardlaw Judith H.
Published: September 2002

The depside 3-chloro-4-O-demethylmicrophyllinic acid
[4-{3′-chloro-2′,4′-dihydroxy-6′-(2′″-oxoheptyl)benzoyl-oxy}benzoic
acid] (2) has been isolated from the lichen
Hypotrachyna leiophylla together with atranorin,
chloroatranorin and 4-O-demethylmicrophyllinic acid (1).
The compound (2) was characterized as the corresponding
p-nitrobenzyl ester, the structure of which followed
from a combination of spectroscopic and degradative evidence.
The Crystal and Molecular Structure of the 1:1 Adduct Hydrate of Pyrazine-2,3-dicarboxylic Acid with 1,1-Diethylurea
Authors: Smith Graham , Kennard Colin H. L.
Published: September 2002

The adduct hydrate of 1,1-diethylurea with pyrazine-2,3-dicarboxylic acid,
[(C6H4N2O4)(C5H12N2O)].H2O
has been prepared and characterized using low-temperature single-crystal X-ray
diffraction methods. A primary asymmetric cyclic hydrogen-bonding interaction,
similar to those found in other adducts of 1,1-diethylurea with the
nitro-substituted aromatic acids, was found between the amide group of the
substituted urea and one carboxylic acid group of the acid. Further peripheral
hydrogen-bonding associations involving both the f irst and the second
carboxylic acid groups, urea and the lattice water molecule result in a ribbon
polymer structure.
The Enzyme Catalysed Stereoselective Transesterification of Phenylalanine Derivatives in Supercritical Carbon Dioxide
Authors: Smallridge A. J. , Wang Z. , Trewhella M. A.
Published: September 2002

The subtilisin Carlsberg catalysed transesterification of N-acetyl phenylalanine methyl ester (1), N-acetyl phenylalanine ethyl ester (2), N-trifluoroacetyl phenylalanine methyl ester (3) and N-trifluoroacetyl phenylalanine ethyl ester (4) was studied in supercritical carbon dioxide. The water content of the reaction affects the reactivity of the system; for the transesterification of the methyl esters with ethanol the optimum concentration of water was determined to be about 0.74 M, while for the transesterification of the ethyl esters with methanol the optimum concentration of water was about 1.3 M. The conversion is also dependent upon the concentration of alcohol; for ethanol, 2% v/v gives the maximum conversion, whilst for methanol, only 0.8-1.2% v/v is required. This is probably due to a difference in the solubility of the substrates in the two alcohol/supercritical carbon dioxide mixtures. The reaction is highly stereoselective, in all cases no evidence for reaction of the D-isomer could be detected by chiral gas chromatography.
Quantitative Determination of Sodium Dodecatungstosilicate Speciation by 183W Nuclear Magnetic Resonance Spectroscopy
Authors: Smith B. J. , Patrick V. A.
Published: September 2002

The speciation and equilibria of sodium dodecatungstosilicate has been determined using 183W nuclear magnetic resonance (NMR) spectroscopy over the pH range 3-13.5. The use of NMR allowed the direct observation of polytungstate anions in aqueous solution and at high concentration (0.5 mol L-1). Using this technique, the speciation of α-[SiW12O40]4-, α-[SiW11O39]8-, α-[NaSiW11O39]7-, α-[H2W12O40]6-, [H8W11O40]6-, [H7W11O40]7-, [W7O24]6-, [H2W12O42]10-, and WO42- was quantified as a function of pH. This work has allowed stability constants for α-[SiW12O40]4- (log K 46) and α-[SiW11O39]8- (log K 86) to be estimated.
Hydrogen-Bonded Ladders formed by Crystalline Diols
Authors: Bishop Roger , Craig Donald C. , Nguyen Vi T. , Scudder Marcia L.
Published: September 2002

Certain diol molecules crystallize from solution as unidirectional
double-stranded ladders. When these two strands assemble in-phase, a
step-ladder arrangement results with the diols linked by
(O–H)4 cycles of hydrogen bonds. Using racemic
diol samples, the preferred arrangement has two enantiomerically pure strands
of opposite handedness. If the two strands assemble out-of-phase, a
staircase-ladder results where the molecules are connected by a
hydrogen-bonded (O–H)n chain. The preferred
arrangement contains enantiomerically pure diol molecules surrounding a
21 screw axis. If a racemic diol is used then either the
crystals contain both (+)- and (–)-ladders or, alternatively,
self-resolution occurs to yield a conglomerate. New diols (7)–(9) were
synthesized and an X-ray investigation confirmed the prediction that these
would produce further double-stranded ladders. These structures revealed new
variants of the staircase-ladder where both enantiomers are present, inclusion
compounds are formed, or crystallographically independent diol molecules are
involved.
Manuscript received: 27 August 2001.
Final version: 5 November 2001.
Multi-Fluorescent Silica Colloids for Encoding Large Combinatorial Libraries
Authors: Matthews Daniel C. , Grøndahl Lisbeth , Battersby Bronwyn J. , Trau Matt
Published: September 2002

Large chemical libraries can be synthesized on solid-support beads by the
combinatorial split-and-mix method. A major challenge associated with this
type of library synthesis is distinguishing between the beads and their
attached compounds. A new method of encoding these solid-support beads,
‘colloidal bar-coding’, involves attaching fluorescent silica
colloids (‘reporters’) to the beads as they pass through the
compound synthesis, thereby creating a fluorescent bar code on each bead. In
order to obtain sufficient reporter varieties to bar code extremely large
libraries, many of the reporters must contain multiple fluorescent dyes. We
describe here the synthesis and spectroscopic analysis of various mono- and
multi-fluorescent silica particles for this purpose. It was found that by
increasing the amount of a single dye introduced into the particle reaction
mixture, mono-fluorescent silica particles of increasing intensities could be
prepared. This increase was highly reproducible and was observed for six
different fluorescent dyes. Multi-fluorescent silica particles containing up
to six fluorescent dyes were also prepared. The resultant emission intensity
of each dye in the multi-fluorescent particles was found to be dependent upon
a number of factors; the hydrolysis rate of each silane–dye conjugate,
the magnitude of the inherent emission intensity of each dye within the silica
matrix, and energy transfer effects between dyes. We show that by varying the
relative concentration of each silane–dye conjugate in the synthesis of
multi-fluorescent particles, it is possible to change and optimize the
resultant emission intensity of each dye to enable viewing in a fluorescence
detection instrument.
Manuscript received: 13 September 2001.
Final version: 18 January 2002.
Current Chemistry: Bisporphyrin Cavities: from Guest Complexation to Molecular Capsule Formation
Authors: Johnston Martin R. , Latter Melissa J. , Warrener Ronald N.
Published: September 2002

Manuscript received: 29 September 2001.
Final version: 17 December 2001.
Review: Crystalline Inclusion Complexes as Media of Molecular Recognitions and Selective Reactions
Authors: Toda Fumio
Published: September 2002

Hexaol host compounds that include guest molecules in a maximum host-to-guest
ratio of 1:6 were prepared. The aromatic hexaol host, hexahydroxytriphenylene,
was found to form a chiral inclusion-complex crystal upon complexation of an
achiral guest molecule. Some interesting and important optical resolutions of
rac-guests by inclusion with a chiral host are
described. When chemical reaction and inclusion in a water suspension medium
are combined, new economical and ecological methods of the preparation of
optically active compounds can be established. When photochemical reactions
are performed on the guests of an inclusion-complex crystal formed with a
chiral host, enantioselective reactions occur and optically active products
can be obtained. Several successful reactions are described.
Crystalline inclusion complexes of guest compounds with various artificial
hosts are useful as media for the following molecular recognitions and
selective reactions in the solid state.
Manuscript received: 4 October 2001.
Final version: 13 November 2001.
Current Chemistry: Electronic Properties of Single-Walled Carbon Nanotubes
Authors: Odom Teri W.
Published: September 2002

This communication describes scanning tunnelling microscopy investigations of
the electronic properties of singlewalled carbon nanotubes (SWNTs). First, the
unique relationship between the atomic structure and electronic properties of
SWNTs is presented. Second, structural defects in nanotubes are addressed, and
quantum size effects in SWNTs are discussed. Lastly, the effects of magnetic
impurities on the low-energy properties of metallic SWNTs are discussed.
Applications and prospects for future research directions are considered.
Manuscript received: 9 October 2001.
Accepted without change.
Septanose Carbohydrates. VII. Preparation of Mono-O-isopropylidene Derivatives of Methyl β-D-Glucoseptanoside and Preparation of Methyl α-L-idoseptanoside and its Derivatives
Authors: Tran T. Q. , Stevens J. D.
Published: September 2002

Three mono-O-isopropylidene derivatives of methyl β-D-glucoseptanoside have been prepared by acid-catalysed hydrolysis of methyl 2,3 : 4,5-di-O-isopropylidene-β-D-glucoseptanoside or by acetonation of methyl β-D-glucoseptanoside. Two of these derivatives have been used for the preparation of methyl 2,3-O-isopropylidene-α-L-idoseptanoside (8a) and methyl 3,4-O-isopropylidene-α-L-idoseptanoside (10a). Hydrolysis of (10a) yielded methyl α-L-idoseptanoside (12a) and acetonation of (8a) and (12a) yielded methyl 2,3 : 4,5-di-O-isopropylidene-α-L-idoseptanoside. Possible conformations of these compounds are discussed.
Michael Addition of Thiols to Sugar Enones. Synthesis of 3-Deoxy-4-Thiohexopyranosid-2-uloses as Key Precursors of 3-Deoxy- and C-2 Branched-Chain 4-Thiosugars
Authors: Uhrig M. L. , Varela O.
Published: September 2002

Benzyl and 2-propyl 6-O-acetyl-3,4-dideoxy-α -D-glycero-hex-3-enopyranosid-2-uloses (2) and (3) were readily prepared by the tin(IV) chloride-promoted glycosylation of glycal (1). The enone system of (2) and (3) underwent a highly diastereoselective Michael addition of thiols (ethanethiol, propane-2-thiol, and benzenemethanethiol) to afford the sulfur-containing hexopyranosid-2-ulose derivatives (4a-c) and (5a-c) in good yields. Sodium borohydride reduction of the carbonyl functionalities of (4b,c) and (5b) led to the corresponding 3-deoxy-4-thiohexopyranosides having the D-xylo (6b), (6c), and (8b) or the D-lyxo (7b), (7c), and (8c) configuration. Standard acetylation of these compounds gave the corresponding per-O-acetyl derivatives (10b), (10c), and (12b) and (11b), (11c), and (13b), useful for confirming all the previous configurational assignments by means of their 1H and 13C nuclear magnetic resonance spectra. Furthermore the 2-ulose (5b) proved to be a key intermediate for the synthesis of C-2 branched-chain 4-thiopyranosides, such as (16). The latter was synthesized by a good yielding ammonium acetate-catalysed Knoevenagel-type condensation of malononitrile with (5b).
Molecular Mimicry of Carbohydrates by Peptides
Authors: Johnson M. A. , Pinto B. M.
Published: September 2002

The use of carbohydrates as drugs and vaccines has several limitations. Molecular mimics of carbohydrates provide an alternative source of compounds to target pathways involving protein-carbohydrate interactions. In recent years, immunological studies have demonstrated the ability of certain peptides to act as molecular mimics of carbohydrates, in that they are able to induce an anti-carbohydrate immune response. Carbohydrate-mimetic peptides that bind to enzymes and lectins have also been discovered. The nature of this mimicry at the molecular level is currently the subject of investigation. Structural data regarding the origin of mimicry are reviewed, and their implications for drug and vaccine design are presented.
Pigments of Fungi. LIX. Synthesis of (1S,3S)- and (1R,3R)-Austrocortilutein and (1S,3S)-Austrocortirubin from Citramalic Acid
Authors: Gill Melvyn , Harte Michael F. , Ten Abilio
Published: September 2002

The naturally occurring tetrahydroanthraquinone
(1S,3S)-austrocortilutein (1) is
synthesized for the first time in enantiomerically pure form by
Diels–Alder cycloaddition between the functionalized butadiene
derivative (8) and the chiral
1,3-dihydroxy-1,2,3,4-tetrahydro-5,8-naphthoquinone (9), the latter being
derived from (R)-citramalic acid (3). The natural
products (1S,3S)-austrocortirubin
(2) and (1R,3R)-austrocortilutein
(5) were also prepared for the first time by using the same strategy.
X-Ray Structural Studies of K6[CoII W12O40]·~16H2O and K5[CoIII W12O40]·~16H2O and Structural Trends Along the [XW12O40] - Series, where X = PV, SiIV, CoIII and CoII
Authors: Nolan Annette L. , Allen Christine C. , Burns Robert C. , Craig Donald C. , Lawrance Geoffrey A.
Published: September 2002

The X-ray crystal structures of
K6[CoII
W12O40]·~16H2O
and
K5[CoIIIW12O40]·~16H2O
are reported. The compounds are isostructural, hexagonal, space group
P 6222, and have
Z 3 with a 19.118(7),
c 12.383(9) Å, V 3919.6(35)
Å3 , and a 19.111(2),
c 12.509(2) Å, V 3956.6(9)
Å3 , respectively. Both anions exhibit the
standard α-Keggin structure, which consists of a central tetrahedrally
coordinated CoII or CoIII ,
surrounded by four groups of three edge-sharing octahedra
(W3O13 subunits) which are linked
in turn to each other and to the central CoO4
tetrahedron by shared oxygen atoms at the vertices. Although thermogravimetric
analyses show that there are c. 16 water molecules per
formula unit in both compounds, only six and three water molecules for the
CoII and CoIII compounds,
respectively, could be crystallographically located. The others are presumably
zeolitic and highly disordered in nature. Structural differences between the
anions on replacement of CoII by
CoIII , as well as comparisons with the related
[PW12O40]3–
and
[SiW12O40]4–
ions, which contain (formally) PV and Si
IV , respectively, are discussed. This comparison
indicates that the W3O13 subunits
become progressively more isolated with increasing size of the central
heteroatom from PV to CoII , while
the bonding within an individual
W3O13 subunit becomes weaker.
Extended-HÜckel molecular orbital calculations are used to examine
stability changes in the polyoxotungstate framework, using the actual
polyoxotungstate geometries of the anions, on variation in size of the central
heteroatom. These are compared to that in the
[H3W12O40]5–
ion, which has two centrally located H+ ions, but
no steric effects. The studies show that no major changes occur in the overall
stability of the framework, but that there is a redistribution in the
contributions of the two types of bridging oxygen atoms to the stability of
the framework, which parallels the progressive isolation and weaker bonding in
the W3O13 subunits.
Caerin 4.1, an Antibiotic Peptide from the Australian Tree Frog, Litoria caerulea. The N.M.R.-Derived Solution Structure.
Authors: Chia Brian C. S. , Carver John A. , Lindner Robyn A. , Bowie John H. , Wong Herbert , Lie Wilford
Published: September 2002

Caerin 4.1
(GLWQK5IKSAA10GDLAS15GIEVG20IKS-NH2)
is an antibiotic peptide isolated from the Australian tree frog
Litoria caerulea. Unlike caerin 1.1, the major peptide
isolated from this species, caerin 4.1 has a narrow spectrum of antibiotic
activity, e.g. it shows selective activity against
Pasteurella haemolytica and
Escherichia coli. Caerin 4.1 consists of 23 amino acid
residues and is comparable in size with other wide-spectrum antibiotic
peptides isolated from Australian amphibians, e.g. caerin 1.1 and maculatin
1.1. An n.m.r. study in trifluoroethanol/water indicates that caerin 4.1
forms an amphipathic α-helix with distinct hydrophilic and hydrophobic
zones. Two regions of well defined helicity (from Gln4 to Ala10 and from Ile17
to Ile21) are separated by a central helical region of greater conformational
variability. The enhanced disorder in this region arises from the presence of
two central glycine residues at positions 11 and 16. However, the degree of
disorder and hence flexibility is much less than in caerin 1.1 where central
proline residues are present instead. This reduced central flexibility may
account for the narrow spectrum of biological activity of caerin 4.1, i.e.
because biological membranes of the various bacteria have different
composition and topology, their optimal interaction with the relatively rigid
caerin 4.1 peptide is not possible.
Novel Analogues of Ebselen-Preparation of 2-Alkylthieno[2,3-d]isoselenazol-3(2H)-ones by Peroxide-Mediated Ring-Closure of 3,3'-Diselenobis(N-alkylthiophencarboxamides).
Authors: Laws Melissa J. , Schiesser Carl H. , White Jonathan M. , Zheng Shi-Long
Published: September 2002

Studies toward the preparation of novel thiophen analogues of the
anti-inflammatory compound Ebselen are presented. We report that treatment of
3,3′ -diselenobis(N-alkylthiophen-2-carboxamides)
(13; R = Me, Pri, But, Ph)
with benzoyl peroxide in benzene under reflux affords the corresponding
2-alkylthieno[2,3-d]isoselenazol-3(2H)-ones
(7) in 10–73% yield, except for the phenyl derivative (13; R
= Ph) which proved too insoluble to react. Irradiation of the PTOC
imidate esters of
2-benzylseleno-N-butylthiophen-3-carboxamide (9) and
3-benzylseleno-N-butylthiophen-2-carboxamide (12)
provides none of the expected Ebselen analogues. This failure to ring-close is
discussed in terms of conformational rigidity in amidyl radicals (22) and
(23).
A New Preparation of the Diastereoisomeric N-Acetylneuraminic Alditols
Authors: Ooi Hua Chee , Marcuccio Sebastian M. , Jackson W. Roy
Published: September 2002

Acylation of the alditols (2) obtained by sodium borohydride reduction of
N-acetylneuraminic acid (Neu5Ac) (1) gives a mixture of
lactones (3) and (4) which can be separated and deprotected without
epimerization yielding pure samples of the diastereoisomeric
N-acetylneuraminic alditols (5) and (6).
The p3 Peptide, a Naturally Occurring Fragment of the Amyloid-β Peptide (Aβ)Found in Alzheimer's Disease, Has a Greater Aggregation Propensity In Vitro Than Full-Length Aβ, But Does Not Bind Cu2+.
Authors: Ali Feda , Thompson Andrew J. , Barrow Colin J.
Published: September 2002

Cerebellar preamyloid from both Down’s syndrome and Alzheimer’s
disease contains the p3 fragment (Aβ 17–40/42) as a major
amyloid-β peptide (Aβ) component. The p3 peptide was previously shown
to form amyloid in vitro, but less readily than
full-length Aβ. Here we show that the p3 peptide has a greater
β-sheet-forming propensity than full-length Aβ. Using circular
dichroism spectroscopy we determined that in aqueous solutions the p3 peptide
forms β-sheet structure more readily than full-length Aβ. The p3
peptide also has a lower α-helical propensity than full-length Aβ in
the structure-forming solvent trifluoroethanol. These results indicate that
the lower amyloidogenicity of the p3 peptide is not related to an inability to
form β-sheet structure. In this study we also show that, unlike
full-length Aβ, the p3 peptide does not bind
Cu2+ ions. This inability to bind copper ions may
explain why the p3 peptide appears to play a lesser role in Down’s
syndrome and Alzheimer’s disease related neurodegeneration than does
full-length Aβ.
Molecular Cocrystals of Aromatic Carboxylic Acids with 1,1-Diethylurea: Synthesis and the Crystal Structures of a Series of Nitro-Substituted Analogues
Authors: Smith Graham , Coyne Michael G. , White Jonathan M.
Published: September 2002

Molecular adducts of 1,1-diethylurea with the nitro-substituted aromatic
carboxylic acids 2-nitrobenzoic acid,
[(C7H5NO4)(C5H12N2O)]
(1), 3-nitrobenzoic acid,
[(C7H5NO4)(C5H12N2O)]
(2), 4-nitrobenzoic acid,
[(C7H5NO4)2(C5H12N2O)]
(3), 3,5-dinitrobenzoic acid,
[(C7H4N2O6)(C5H12N2O)]
(4), 5-nitrosalicylic acid,
[(C7H5NO5)(C5H12N2O)]
(5) and 3,5-dinitrosalicylic acid,
[(C7H4N2O7)(C5H12N2O)]
(6), have been prepared and characterized by using infrared spectroscopy, and,
in the case of four of these [(1), (4), (5) and (6)], by
single-crystal X-ray diffraction methods. In all examples, primary cyclic
hydrogen-bonding interactions are found between the amide group of the
substituted urea and the carboxylic acid group of the acid, while further
peripheral associations result predominantly in simple chain polymeric
structures, and in one case [adduct (1)], a cyclic tetramer. The
crystal structure of the parent 1,1-diethylurea has also been determined,
revealing a cyclic hydrogen-bonded tetramer which forms into a chain polymer
by weak hydrogen-bonding associations.
Synthesis and Structural Characterization of N-Methyl-DL-glutamic Acid
Authors: Hughes Andrew B. , Mackay Maureen F. , Aurelio Luigi
Published: September 2002

The solid-state conformation of racemic N-methylglutamic
acid has been defined by single-crystal X-ray crystallography. Orthorhombic
crystals belong to the space group Pbca with
a 15.219(2), b 10.583(1),
c 9.595(1) Å and Z 8. The
structure was refined to a final R value of 0.049 for
the 1285 measured data. In the crystal the molecules adopt a zwitterionic form
with protonation having occurred at the amino nitrogen atom. The a-carboxyl is
unprotonated with the d-carboxy group retaining a proton. The i.r. spectrum
shows absorptions which also are indicative of the amino acid being in the
zwitterionic form. Intermolecular H-bonds involving the carboxylate proton and
the two protons on the N-atom link the molecules into a three-dimensional
network in the crystal.
Advances in inoculant technology: a brief review
Authors: Date R. A.
Published: September 2002

Legume seed inoculants by default must be compatible with current farming
practice. It is rare that farming practice is changed to accommodate a
technology that delivers a high quality inoculant. Production of inoculants,
therefore, is an exercise in practical (applied) microbiology. The
agricultural industry demands that an inoculant is easy to apply and that it
works reliably under a range of conditions. Such demands call on a range of
technologies and skills on the part of researchers, manufacturers and users.
Inoculants are prepared from either submerged or semi-solid culture and
applied either to the seed or directly to the soil in different forms. The
form used is directed by the requirements of the legume host and its
associated husbandry techniques. Agar, broth (concentrated and frozen),
oil-dried, lyophilized and powdered carrier (mostly peat) formulations are
used. Advantages and disadvantages of each are discussed briefly. Peat
formulations dominate due to good survival of the root-nodule bacteria and
their ease of use. There has not been an alternative (non-peat) formulation
that has performed consistently better than the peat forms in field
evaluation. Despite higher quality and longer shelf life of dried forms as
inoculants per se they have not been superior to
peat-based forms either as seed or soil-applied inoculant.
The review looks briefly at aspects of production that may influence (improve)
survival of root-nodule bacteria and concludes that there are windows of
opportunity for new developments. Aspects that may influence quality of peat
cultures and, in particular, those that may provide better survival of the
inoculant on the seed include: growth phase at the time of mixing with a
carrier, rate of drying and of re-hydration (both as inoculant and as inoculum
on the seed), carrier characteristics (including additives and stickers) and
inoculation methodology.
Few significant advances have occurred in the 1990s. The challenge for the
future is to develop a technology that provides long-term survival of
root-nodule bacteria on the seed or in granules (for soil application) to the
extent that ‘on-farm’ inoculation requirements can be replaced by
a reliable pre-sale seed inoculation step.
A field method for statewide ground-truthing of a spatial pasture growth model
Authors: Hassett R. C. , Wood H. L. , Carter J. O. , Danaher T. J.
Published: September 2002

This paper describes an innovative method, commonly referred to as
‘spider mapping’, that allows pasture biomass and related data to
be collected over large areas in a timely and efficient manner. Spider mapping
was developed initially to collect data to allow calibration and validation of
a spatial and temporal pasture growth model operating across Queensland on a 5
km grid basis. Two field officers made over 220 000 estimates and collected
about 1300 samples of pasture biomass between January 1994 and August 1995. A
number of selected biomass samples were analysed for nitrogen, phosphorus and
carbon content. In addition, data were also collected on foliage projective
cover and tree basal area for a range of woodland communities and both
variables compared with mean long-term Normalised Difference Vegetation Index
values derived from a time series of National Oceanographic and Atmospheric
Administration satellite imagery. Both variables were strongly related to the
satellite data with overstorey foliage projective cover having the strongest
non-linear correlation (r2
= 0.91). The method described here is currently being used in related
work in the rangelands of New South Wales, South Australia, Western Australia
and the Northern Territory.
Quantitative and molecular genetic influences on properties of beef: a review
Authors: Burrow H. M. , Moore S. S. , Johnston D. J. , Barendse W. , Bindon B. M.
Published: September 2002

The scientific literature is reviewed to identify quantitative and molecular
genetic influences on quantity and quality of beef. Genetic variation between
breeds is of similar magnitude to genetic variation within breeds for many
economically important traits. Differences between breeds are significant and
large for most carcass and beef quality attributes, including beef tenderness,
although differences for sensory juiciness and flavour are of little practical
importance. For traits such as beef tenderness, between-breed differences may
be more easily exploited than within-breed differences, because exceptional
breeds are easier to identify than exceptional animals. Effects of heterosis
on carcass and beef quality attributes are relatively small (3% or
less), with most effects mediated through heterotic effects on weight. Carcass
composition traits (e.g. carcass weight, fat thickness and marbling) are
moderately to highly heritable. Most estimates of retail beef yield percentage
are highly heritable, offering good potential for within-breed selection for
the trait, although a moderate to strong antagonistic relationship exists
between yield and marbling. This relationship needs to be considered in
within-breed selection programs for yield percentage. Early estimates of
heritability of objective measures of beef tenderness (Warner Bratzler shear
force values) indicated tenderness was moderately to highly heritable. Recent
estimates using larger numbers of carcasses and more discriminatory methods of
analysis indicate that beef tenderness is lowly heritable in
Bos taurus breeds and moderately heritable
inBos indicus and
Bos indicus-derived breeds. Within breeds, measures of
24-h calpastatin activity are genetically strongly correlated with shear force
values but are more heritable. However, phenotypic correlations between shear
force values and 24-h calpastatin activities are low. There are also
inconsistencies in relationships between these measurements across breeds. Low
correlations between tenderness in different muscles, low to moderate
heritabilities and inconsistent variation within- and between-breeds for
traits such as 24-h calpastatin activity suggest that genetic improvement in
beef tenderness may be difficult. The possibility exists that significant
mitochondrial genetic effects occur for some carcass and beef quality
attributes. A major gene for muscular hypertrophy in cattle significantly
affects carcass and beef quality characteristics. Genome-wide screening of DNA
markers indicates a number of putative Quantitative Trait Loci (QTL)
associated with carcass and meat quality characteristics. Published data for
these QTL are summarised. Strategies to combine quantitative and molecular
genetic information to maximise genetic progress are discussed.