bluuebunny/crossref_metadata_2025 huggingface dataset:
Interspecific amplification of tea tree (Melaleuca alternifolia-Myrtaceae) microsatellite loci-potential implications for conservation studies
Authors: Rossetto M. , Harriss F. C. L. , Mclauchlan A. , Henry R. J. , Baverstock P. R. , Lee L. S.
Published: September 2002

This study investigated the interspecific amplification of 35 microsatellite
loci developed for M. alternifolia across seven other
species within the Myrtaceae. All the primers used gave successful
amplification of loci in at least one of the species tested. The level of
success varied between species; 88.6% of primers gave amplification
products for Melaleuca spp., 74.3% for
Callistemon salignus, 45.7% for
Eucalyptus spp. and 25.7% for
Backhousia citriodora. Sequencing of a number of
amplification products confirmed the presence of microsatellites in those
loci. This study shows that the development of species-specific microsatellite
libraries might not always be necessary. Cross-species amplification could
enable the application of microsatellite technology to studies with limited
resources, a feature characteristic of conservation projects.
Morphological and genetic variation in the endangered Victorian endemic grass Agrostis adamsonii Vickery (Poaceae)
Authors: James E. A. , Brown A. J.
Published: September 2002

Until 1987, Agrostis adamsonii Vickery was known only
from a single collection made in 1853 and was thought to be extinct. Further
populations have been located but conservation of the species is hampered by a
lack of taxonomic and genetic information. Variation within and between
species was assessed morphometrically and by random amplified polymorphic DNA
(RAPD) analysis. RAPD analysis has confirmed that the separation of
A. adamsonii from two other similar species on the basis
of morphological characters has a genetic basis and enables identification of
A. adamsonii in the absence of fertile material. RAPD
analysis has also provided information on the genetic diversity within
A. adamsonii. Agrostis adamsonii
is confirmed as a well-supported species with all six populations studied
showing a high degree of similarity to each other but with evidence of genetic
differentiation. Genetic diversity is lower compared to the widespread
A. avenacea J.F.Gmel., but significantly higher than in
the more restricted A. billardierei R.Br., with a
Shannon information index of 0.0147 (average over populations) compared to
0.0068 and 0.1389 for A. billardierei and
A. avenacea, respectively. A very high level
(82.1%) of RAPD diversity occurs among populations of
A. adamsonii. Gene flow between populations appears
highly restricted and will have implications for the management of extant
populations.
Influence of season, drought and xylem ABA on stomatal responses to leaf-to-air vapour pressure difference of trees of the Australian wet-dry tropics
Authors: Thomas D. S. , Eamus D. , Shanahan S.
Published: September 2002

This paper reports the results of two experiments undertaken to investigate
the influence of season and soil drying on stomatal responses to leaf-to-air
vapour pressure differences. We examined the response of stomatal conductance
to increasing leaf-to-air vapour pressure difference, in the wet and dry
seasons, of five tropical tree species. We also examined leaves of these
species for anatomical differences to determine whether this could explain
differences in stomatal sensitivity to leaf-to-air vapour pressure
differences. Finally, we conducted a split-root experiment with one of those
species to look for interactions between xylem abscisic acid concentration,
predawn water potential, leaf area to root mass ratio and stomatal responses
to leaf-to-air vapour pressure differences.
Stomatal conductance declined linearly with increasing leaf-to-air vapour
pressure difference in all species. Leaves that expanded in the
‘dry’ season were more sensitive to leaf-to-air vapour pressure
differences than those that had expanded in the ‘wet’ season. The
value of leaf-to-air vapour pressure difference where 50% of
extrapolated maximum stomatal conductance would occur was 5.5 kPa for wet
season but only 3.4 kPa for dry season leaves. In the wet season,
transpiration rate increased with increasing leaf-to-air vapour pressure
difference in most example species. However, in the dry season, transpiration
was constant as leaf-to-air vapour pressure differences increased in most
cases. There were significant changes in the proportion of cell wall exposed
to air space in leaves, between wet and dry seasons, in three of four species
examined.
In the split-root experiment, a very mild water stress increased stomatal
sensitivity to leaf-to-air vapour pressure differences, and stomatal
conductivity declined linearly with decreasing predawn water potential.
However, levels of ABA in the xylem did not change, and stomatal sensitivity
to exogenous ABA did not change. The ratio of leaf area to root mass declined
during water stress and was correlated to changes in stomatal sensitivity to
leaf-to-air vapour pressure differences.
E.P.R. Spectroscopic Studies of the Reactions of Chromium(VI) with L-Ascorbic Acid in Buffer Solutions: Implications for Understanding the Roles of Chromium(V) and Chromium(IV) Species and the Buffer Dependences of In Vitro DNA Damage
Authors: Zhang Lianbo , Lay Peter A.
Published: September 2002

The reaction of chromium(VI) with L-ascorbic acid (AsA) in buffer solutions
was investigated by e.p.r. spectroscopy. Chromium(V)/ascorbate complexes
with signals at giso = 1.9791 and chromium(VI)/ascorbate/peroxo
complexes with signals at giso = 1.9819 and
giso = 1.9824 were observed in all buffers. New
signals at giso values of 1.9765 and 1.9781 were
observed in Tris–HCl [tris(hydroxymethyl)aminomethane
hydrochloride] buffer and were assigned to a mixed-ligand
ascorbate/Tris complex of chromium(V),
[CrO(ascorbate)(Tris)]2– , and a
Tris/peroxo species,
[CrO(O2)(Tris)]2– , respectively. The
speciation of the e.p.r.-active chromium(V) complexes detected from solutions
with other buffers, such as HEPES, cacodylate and phosphate, was not
influenced by the buffer type. Preincubation of catalase with ascorbate
solutions inhibited the formation of the chromium(V) peroxo species in all
buffers. Manganese(II) reduces the chromium(V) species produced in the
reaction, which has shown that it is inappropriate to use manganeses(II) as a
selective reagent for monitoring the concentrations of chromium(IV) in such
reactions. In particular, manganeses(II) reacts more efficiently with the
chromium(V) species that are most damaging to DNA
in vitro, viz., the mixed-ligand
chromium(V)/ascorbate/peroxo complexes. The correlation of the present
results with those of in vitro DNA damage experiments
reported in the literature has revealed that the
chromium(V)/ascorbate/peroxo species are the major species responsible
for the in vitro DNA strand breaks in all of the buffer
systems. These species are not expected to be as important
in vivo.
Characterization of the Minor cis Isomer of a Dipendant Polyamino Acid Macrocycle as a Dimeric Nickel(II) Complex
Authors: Wilkes Eric N. , Hambley Trevor W. , Lawrance Geoffrey A. , Maeder Marcel
Published: September 2002

The dipendant-arm polyamino acid macrocycle
13-amino-13-methyl-1,4,8,11-tetraazacyclotetradecane-6-carboxylate (acammac),
characterized earlier as the major trans isomer (3), has
been isolated as the minor cis isomer (4) by
crystallization as the [Ni(4)](ClO4) complex.
The complex has been examined by an X-ray crystal structure analysis, and the
cation exists as a dimer with each carboxylate group bound both to its
‘parent’ nickel atom and bridging to the adjacent nickel atom. The
macrocycle adopts a folded geometry, each nickel atom appearing as a
cis-NiN4O2
chromophore. The pendant primary amine group and three of the four secondary
amine groups are also coordinated, whereas the fourth secondary amine group is
not coordinated but stabilized by a proton bridging within a superbase between
the uncoordinated amine and one of the coordinated amines.
Triterpenoid Constituents in the Bark of Balanops australiana
Authors: Setzer William N. , Setzer Mary C. , Peppers R. Lynton , McFerrin Michael B. , Meehan Edward J. , Chen Liqing , Bates Robert B. , Nakkiew Pichaya , Jackes Betsy R.
Published: September 2002

Two new triterpenoid natural products (friedelane-3,21α-diol and
friedelane-3α,28,29-triol) have been isolated from the chloroform bark extract
of Balanops australiana from Paluma, north Queensland,
Australia. The known triterpenoids betulinic acid, friedelin, canophyllol,
zeylanol and 21α-hydroxyfriedelan-3-one were also isolated. The structures of
the compounds were elucidated on the basis of spectral analysis. A
single-crystal X-ray structural analysis has been carried out on
21α-hydroxyfriedelan-3-one.
Tris(dimethylphenylphosphine)ruthenium(0) Complexes of n4-Coordinated Polycyclic Aromatic Hydrocarbons
Authors: Bennett Martin A. , Bown Mark , Hockless David C. R.
Published: September 2002

From the reaction of
[Ru2Cl3(PMe2Ph)6]
Cl with the appropriate radical anions, yellow complexes of general formula
[Ru(PMe2Ph)3(η4-arene)]
[arene = naphthalene
(C10H8) (1), anthracene
(C14H10) (2), and triphenylene
(C18H12) (3)] have been
isolated in poor yield and characterized by elemental analysis, n.m.r.
(1H, 13C,
31P) spectroscopy and single-crystal X-ray diffraction.
Crystal data: (1), monoclinic,
C2/c, a
31.096(8), b 12.012(4), c
17.078(8) Å, β 104.41(3)˚, V 6178(4)
Å3, ? 8, refined to
final R value of 0.032 with use of 3641 reflections
[I > 3σ(I)];
(2), monoclinic, C2/c,
a 55.909(4), b 14.348(5),
c 17.573(5) Å, β 105.41(1)˚,
V 13590(6) Å3,
Z 16 (two molecules per asymmetric unit), refined to
final R value of 0.049 with use of 7770 reflections
[I > 3σ(I)]; (3), mono-clinic,
Pn, a 9.377(3),
b 12.229(3), c 15.975(3) Å,
β 103.51(2)˚, V 1781.2 (7) Å3,
Z 2, refined to final R value of
0.026 with use of 2830 reflections [I >
3σ(I)]. In each case, coordination of the
zerovalent metal fragment
Ru(PMe2Ph)3 to the diene section
of one of the terminal rings causes the aromatic molecule to be folded by
c. 40˚ at the outer carbon atoms of the diene. The
coordination geometry about ruthenium is approximately square pyramidal, with
the diene and two tertiary phosphines in the equatorial plane and the
remaining tertiary phosphine in the axial site.
Synthesis, Characterization and Crystal Structures of Monomeric and Imidazolate-Bridged Polymeric Copper(II) Complexes of 5-Methyl-1,5,9-triazanonane
Authors: Zhu Hai-Liang , Yu Xiao-Lan , Chen Xiao-Ming
Published: September 2002

Two complexes
[Cu(mtan)(H2O)(ClO4)](ClO4)
(Im = imidazolate) (1) and
[Cu(mtan)(Im)]n
(ClO4)2n (mtan =
5-methyl-1,5,9-triazanonane) (2) have been prepared and characterized.
Single-crystal X-ray analysis reveals that (1) crystallizes in the
orthorhombic space group Pbcm, with
a 8.906(5), b 12.255(6),
c 14.821(4) Å and V 1618(1)
Å3, and complex (2) crystallizes in the
orthorhombic space group Pca21,
with a 11.125(7), b 9.149(6),
c 15.180(7) Å and 1545(1)
Å3. The copper(II) atom in complex (1) is in a
distorted square-pyramidal geometry, being coordinated by three nitrogen atoms
from an mtan ligand and one oxygen atom from an aqua ligand at the basal plane
and one perchlorate oxygen atom at the apical position. The structure of
complex (2) features polymeric cationic chains composed of
[Cu(mtan)(Im)]+ repeating units and
discrete perchlorate anions. The Cu(1) atom in each unit has a severely
distorted trigonal-bipyramidal geometry, being coordinated by three nitrogen
atoms from one mtan ligand and two nitrogen atoms from two Im groups. The
structural units are linked by -Im groups to give one-dimensional chains. The
variable-temperature magnetic measurement on the powder sample of (2) reveals
intrachain, medium antiferromagnetic interaction with g
= 2.240 and J = –36.45 cm–1 through the -Im bridges.
A 'Glycosynthase'-assisted Synthesis of Some Epoxyalkyl β-C-Oligosaccharides
Authors: Fairweather Jon K. , Stick Robert V. , Withers Stephen G.
Published: September 2002

A series of alkenyl β-D-C-glucopyranosides
has been glycosylated with α-D-glucopyranosyl fluoride in a
‘Glycosynthase’ reaction to yield a range of alkenyl
β-C-cellobiosides and -triosides and in one case a -C-cellotetraoside. Conversion of some of the alkenyl β
-D-C-oligosaccharide products into their corresponding
epoxides and subsequent deprotection under standard conditions have afforded a
panel of epoxyalkyl β -C-oligosaccharides
for evaluation as inhibitors of retaining β-glycan hydrolases.
An ent-Kaurane Diterpenoid from Croton tonkinensis Gagnep
Authors: Son Phan Tong , Giang Phan Minh , Taylor Walter C.
Published: September 2002

A new ent-kaurane diterpenoid,
ent-7β-hydroxy-15-oxokaur-16-en-18-yl acetate (1),
has been isolated from the leaves of Croton tonkinensis
Gagnep. (Euphorbiaceae). Its structure was established mainly by
1 H and 13 C nuclear magnetic
resonance (n.m.r.) spectroscopy.
Group 15 Complexes with α-Hydroxy Carboxylic Acids: 7. The Preparation and Structure Determination of Sodium (+)-Tartrato Arsenate(III), [Na8As10(C4H2O6)8(C4H3O6)2(H2O)19]n; Silver(I) (+)-Tartrato Arsenate(III), [Ag9As10(C4H2O6)9(C4H3O6)(H4As2O5) (H2O)10]n and Rubidium Citrato Antimonate(III), [Rb2Sb4(C6H5O7)2(C6H6O7)2(C6H7O7)4(H2O)2]
Authors: Bott Raymond C. , Smith Graham , Sagatys Dalius S. , Lynch Daniel E. , Kennard Colin H. L.
Published: September 2002

The structures of sodium (+)-tartrato arsenate(III),[Na8As10(C4H2O6)8(C4H3O6)2(H2O)19]n(1), silver (+)-tartrato arsenate(III),[Ag9As10(C4H2O6)9(C4H3O6)(H4As2O5)(H2O)10](2) and rubidium citrato antimonate(III)[Rb2Sb4(C6H6O7)6(C6H7O7)2(H2O)2](3) have been determined by X-ray methods and refined to residuals of 0.085(1), 0.072 (2) and 0.065 (3) for 5018, 4487 and 8207 observed reflections,respectively. The (+)-tartrato complexes (1) and (2) are similar instructure to the two known isomorphous silver(I) (+)-tartratoarsenate(III) complexes in that independent anionic[As2(tartrate)2] dimericcages are linked to the sodium or silver counter-cations, respectively,through free carboxyl oxygen atoms. However, the structures are made morecomplex by the presence of labile water molecules in the lattice, resulting insome disorder. Furthermore, charge balance in both (1) and (2) requires thepresence of two and one tri-negative tartrato units, respectively, among theten independent tartrate units in each structure, an unusual feature for Asand Sb complexes with this ligand species. Bond distances within the fivearsenic(III)-(+)-tartrate dimers in each structure are: As–O(hydroxy), 1.75(2)–1.84(2) Å (1); 1.75(3)–1.83(2) Å(2) and As–O (carboxy), 1.94(2)–2.13(3) Å (1);1.95(2)–2.14(2) Å (2). In addition, the structure of (2) has twoshort Ag–As bonds [2.500, 2.524(3) Å] in the terminalsites of two of the f ive independent dimers, as well as an additionalAg–As bond [2.613(4) Å] to an unusual dimeric arseniousacid residue(H4As2O5),part of an As2AgO3 hetero-ringforming the polymeric network structure. The antimony(III) citrate complex (3)is isomorphous and isostructural with the previously reported potassiumanalogue which involves mixed-valence citrato ligands in conventionalbis-chelate four-coordination about the antimony centres, linked by bothseven- and eight-coordinate rubidium ions [Rb–O,2.743(10)–3.102(9) Å]. The arsenic and antimony atoms in allcompounds have typical distorted pseudo-trigonal bipyramidal stereochemistry.
Photolytic, Pyrolytic and Trimethylamine N-Oxide Induced CO Removal from [BiFe4(CO)16]3–: Synthesis, X-Ray Crystal Structure and Properties of [N(PPh3)2]2[Bi2Fe5(CO)17]
Authors: Rossignoli Monica , Burns Robert C. , Craig Donald C.
Published: September 2002

The formation of anionic-cluster species from compounds containing the ‘open’ (i.e. non-cluster) [BiFe4(CO)16]3– (or [Bi{Fe(CO)4}4]3–) ion following loss of CO as a result of photolytic, pyrolytic and chemical means has been investigated. Photolysis of salts of the [BiFe4(CO)16]3– ion in acetonitrile, where the associated cations are [N(PPh3)2]+ or [NEt4]+, produce a range of species including [Bi2Fe5(CO)17]2–, [Bi2Fe4(CO)9]2–, [Bi2Fe3(CO)9]2–, [Fe2(CO)8]2– and [Fe4(CO)13]2–, with the distribution of species being cation dependent. The previously unknown [Bi2Fe5(CO)17]2– ion was obtained as the [N(PPh3)2]+ salt, crystallizing in the triclinic space group P 1, with a 15.851(7), b 17.199(8), c 20.020(8) Å, α 114.72(2), β 95.51(3), γ 113.01(2)o, Z 2 and V 4338(3) Å3. The structure was determined by X-ray diffraction methods to an R of 0.035 (Rw = 0.040) for 6778 independent observed reflections. The anion consists of a central square-based pyramidal ‘nido-Bi2[Fe(CO)3]3’ cluster unit, with two external Fe(CO)4 fragments attached to the two trans four-coordinate bismuth atoms located in the base of the pyramid. A thermogravimetric study of [NEt4]3[BiFe4(CO)16] indicated decomposition above 150˚C, with an apparent loss of three CO molecules per [BiFe4(CO)16]3– ion below 160˚C. Decomposition was complete by 205˚C and also involved pyrolysis of the [NEt4]+ cations. Pyrolysis of solid [NEt4]3[BiFe4(CO)16] at 160˚C for several hours under N2 implicated an intermediate species in the Bi/Fe carbonyl anion system, probably [Bi2Fe3(CO)9]2–, in addition to the [Fe2(CO)8]2– ion, although the final product obtained was found to be [Bi2Fe4(CO)13]2–. Reaction of [NEt4]3 [BiFe4(CO)16] with trimethylamine N-oxide in acetonitrile, in an attempt to selectively remove CO by chemical means, lead to the slow formation of [Bi2Fe4(CO)13]2– and a little [Bi2Fe5(CO)17]2–, although the [Bi2Fe5(CO)17]2– was observed to react slowly with (CH3)3NO to give [Bi2Fe4(CO)13]2– as the major product. Conversion of [Bi2Fe5(CO)17]2– to [Bi2Fe4(CO)13]2– is likely initiated through nucleophilic attack at the axial carbon site of a pendant Fe(CO)4 group, according to extended-HÜckel molecular orbital calculations. Calculations also show that there is no instability introduced in having a second pendant Fe(CO)4 attached to the central cluster unit, and the anion can be produced by reaction of [Bi2Fe4(CO)13]2– with Fe2(CO)9 in tetrahydrofuran, through the addition of an Fe(CO)4 fragment to the three-coordinate bismuth atom in the anion. The other product of the reaction is volatile Fe(CO)5, which is easily separated from the desired product.
A Unique Rare-Earth Cluster within a Calixarene Sandwich: Parallels in the Chemistry of Cyclosiloxanes and Calixarenes
Authors: Bilyk Alexander , Hall Annegret K. , Harrowfield Jack M. , Hosseini Mir Wais , Skelton Brian W. , White Allan H.
Published: September 2002

Determination of the crystal structure of a complex obtained by the reaction
of the dimethyl sulfoxide (dmso) solvate of neodymium(III) nitrate with
p-t-butyltetrathiacalix[4]arene in
dimethylformamide (dmf) in the presence of base showed a regular, planar
cluster of four neodymium atoms bridged by a hydroxyl group to be sandwiched
between two fully deprotonated calixarene moieties. The sulfur and oxygen
donor atoms of the calixarenes are both involved in coordination to the
rare-earth atoms. Both dmf and dmso are found as ligands on neodymium but
occupation of the calixarene cavity is by dmf only. The proposed overall
stoichiometry of the complex is
[Nd4(OH){(p-t-butyltetrathiacalix[4]arene-4H)(dmf)}2(dmf)6(dmso)2](NO3)3.3H2O.
Current Chemistry: Biomineralization-Controlled Microarchitecture in the Radula Teeth of Chitons and Limpets
Authors: Webb John , Brooker Lesley R. , Lee Alasdair P. , Hockridge James G. , Liddiard Kathryn J. , Macey David J. , van Bronswijk William
Published: September 2002

Manuscript received: 17 October 2001.
Final version: 20 December 2001.
Enzymatic Synthesis and Analysis of Large-Ring Cyclodextrins
Authors: Zheng M. , Endo T. , Zimmermann W.
Published: September 2002

Large-ring cyclodextrins (LR-CD) are cyclic α-1,4-glucans composed of nine to more than several hundred glucopyranose units. Cyclodextrins are able to form highly specific inclusion complexes with a wide range of guest molecules thereby modifying their physicochemical properties. Only in the past 10 years, LR-CD with a degree of polymerization between 9 and 32 have been isolated and characterized. The structures of these LR-CD show novel features distinct from those of the extensively studied α- β-, and γ-CD composed of six, seven, and eight glucopyranose units, respectively. Recent work on the enzymatic synthesis of LR-CD has confirmed the ability of different 4-α-glucanotransferases to form large cyclic α-1,4-glucans from amylose and amylopectin, depending on the specificity of the enzyme used and on the substrate and reaction conditions chosen. The potential of LR-CD for specific host-guest interactions and corresponding applications has been demonstrated.
Glycosynthases: Mutant Glycosidases for Glycoside Synthesis
Authors: Williams S. J. , Withers S. G.
Published: September 2002

Glycosynthases are engineered mutant glycosidases that catalyse the formation of a glycosidic bond from a glycosyl donor and an acceptor alcohol. They are constructed by mutation of the enzymic nucleophile of a retaining glycosidase to a small non-nucleophilic residue. To date, five glycosynthases have been reported capable of synthesizing a range of β-glycosidic linkages. Methods to integrate protecting groups into glycosynthase-mediated glycosylations have been developed that broaden their applicability and enable finer control over product formation. Mutagenesis studies have improved the catalytic power of the original Abg glycosynthase, and a general methodology has been developed that allows the rapid screening of libraries of mutant glycosynthases for catalysts with improved activity. A method for determining aglycon substrate specificity has been developed to define the limits of substrate variation tolerated by a parent glycosidase and thence the derived glycosynthase. Together, these developments portend a bright future for the discovery of new glycosynthases and their widespread application as catalysts to assist in the rapid and efficient assembly of complex glycoconjugates.
Synthetic Studies on Sialoglycoconjugates. CXXIV. Total Synthesis of O-Glycan on the L-Selectin Ligand GlyCAM-1
Authors: Otsubo N. , Ishida H. , Kiso M.
Published: September 2002

The total synthesis of O-glycans containing the sulfated sialyl Lex (sLex) determinant on GlyCAM-1 (1), the counter-receptor glycoprotein for L-selectin, was accomplished by a simultaneous glycosylation procedure. The glycosylation of the lactoside acceptor (4) with the 2-azidogalactopyranosyl trichloroacetimidate donor (3) resulted in the desired trisaccharide (5). This trisaccharide, after transformation to the glycosyl acceptor, was successfully coupled with the phenylthioglycoside of glucosamine (13) to give the core 6 structure (14). Following proper manipulation of the protecting groups for the hydroxyl, as well as the amino function, the resulting free hydroxyl of the tetrasaccharide at C3 of the GlcNAc was then fucosylated to give the desired pentasaccharide (19). This pentasaccharide was converted into the key glycosyl acceptor (21), which was then simultaneously glycosylated with the sialyl α (2→3)-galactosyl trichloroacetimidate (22), forming the desired nonasaccharide (23). Finally, sulfation of the 6-OH of the GlcNAc residue and removal of all the protecting groups furnished the spacer-armed O-glycans on GlyCAM-1 (1).
Essay: Chemistry for the Future at the IUPAC Chemistry Congress
Authors: Trau Matt
Published: September 2002

Manuscript received: 2 January 2002.
Final version: 4 February 2002.
On The Synthesis of Pyridinylthiobarbituric Acids
Authors: Deady L. W. , Ganame D. , Quazi N. H. , Zanatta S. D.
Published: September 2002

The reaction of N-(pyridin-3-yl) and -4-yl thiourea derivatives with malonyl dichloride in trifluoroacetic acid is shown to be an efficient synthesis of the corresponding thiobarbituric acids. The pyridin-2-yl analogue cleaved and produced, instead, 2-hydroxy-4H-pyrido[1,2a]pyrimidin-4-one.
Indole Alkaloids from Two Species of Ophiorrhiza
Authors: Dachriyanus  , Arbain Dayar , Putra Deddi Prima , Sargent Melvyn V. , Susila Revi , Wahyuni Fatma Sri
Published: September 2002

Extraction of the aerial parts of Ophiorrhiza rosacea
Ridley (Rubiaceae) has yielded harman-2-oxide (1). Extraction of the aerial
parts of O. kunstleri King yielded the alkaloids
palicoside (3) and 3,14-didehydro-19- methylnormalindine (8). The structures
of these compounds followed from their spectroscopic properties.
Gauging the Donor Ability of the C-Si Bond. Results from Low-Temperature Structural Studies of gauche and Antiperiplanar β-Trimethylsilyl-cyclohexyl Esters and Ethers by Use of the Variable Oxygen Probe.
Authors: Green Alison J. , Giordano Josie , White Jonathan M.
Published: September 2002

A plot of C–OR bond distance against
pKa(ROH) for esters and ether
derivatives of the antiperiplanar β-silyl alcohol (4) has a slope of
–5.310–3. This represents a stronger
response of the C–OR distance than was observed for the corresponding
gauche β-silyl alcohol (5) and its derivatives. This
result is consistent with the greater donor ability of a C–Si bond
compared with a C–C bond. Comparison of these plots with those
previously reported for derivatives (3) of tetrahydropyran-2-ol reveals that a
C–Si bond is a weaker donor than an oxygen non-bonded pair of electrons.
An estimate of the pKa value for
2,4-dinitrobenzenesulfenic acid (14) was derived from these plots.
A New Brominated Diphenyl Ether from the Marine Sponge Dysidea herbacea.
Authors: Bowden Bruce F. , Towerzey Leanne , Junk Peter C.
Published: September 2002

Samples of Dysidea herbacea collected at Pelorus Island,
Great Barrier Reef, Australia, afforded a new polybrominated diphenyl ether
(1). The structure was determined by n.m.r. two-dimensional methods and by an
X-ray diffraction study. N.m.r. spectral assignments for (1) and some
previously reported isomeric polybrominated diphenyl ethers are discussed.
A survey of wildflower farms in the south-west of Western Australia for Phytophthora spp. associated with root rots
Authors: Boersma J. G. , Cooke D. E. L. , Sivasithamparam K.
Published: September 2002

A survey of wildflower farms in the south west of Western Australia, was
conducted during spring of 1997 and autumn 1998 to determine the prevalence of
Phytophthora infestations. Thirty-seven randomly
selected farms ranging in size from 0.5 to =30 ha were visited. The
main crop plants grown included species of Banksia,
Boronia, Chamelaucium,
Conospermum, Eucalyptus,
Protea, and Leucadendron. Eighteen
sites were found to have infestations of Phytophthora.
Of these, 14 sites had P. cinnamomi, and 2 sites had P. cryptogea. P.
cactorum, P. citricola and P. nicotianae were each found at only single
locations. One site was found to have both P. cinnamomi and P. cryptogea.
Species of Phytophthora were identified morphologically, isozymically, and
using species-specific PCR primers. Not every species could be identified by
all 3 methods. There was no apparent association between geographical location
and the occurrence of Phytophthora spp.
Sources of variation in mechanical shear force measures of tenderness in beef from tropically adapted genotypes, effects of data editing and their implications for genetic parameter estimation
Authors: Johnston D. J. , Reverter A. , Robinson D. L. , Ferguson D. M.
Published: September 2002

Warner-Bratzler shear force measures of tenderness were taken on 2 muscles
from 2661 carcasses from 3 tropically adapted breeds: Belmont Red, Brahman and
Santa Gertrudis. The data were used to determine suitable methods of editing
the raw data and to partition sources of variation for meat tenderness
measured in 2 different muscles. The effect of different methods of electrical
stimulation was examined: non-stimulated, extra low voltage or high voltage.
The results showed stimulation method had a large effect on the mean and
variance of the shear force. Non-stimulated slaughter groups were more
variable than high voltage treated groups, which were more variable than low
voltage treated groups. The effect of stimulation method was greater for shear
force measured in M. longissimus dorsi than in
M. semitendinosus. The variability in tenderness
associated with different methods of electrical stimulation and the larger
effect seen for the M. longissimus muscle suggest cold
shortening, a processing effect, may have occurred in some of the slaughter
groups. Several methods of editing outlier records were used and the effects
of removing these records on the partitioning of variances among the
independent variables of tenderness were examined. Removal of non-stimulated
slaughter groups and other outliers resulted in a large reduction in slaughter
group variance and residual variance, with the estimate of heritability for
shear force of the M. longissimus increasing from 19 to
39%. Beef tenderness, as measured mechanically, could be improved by
selection. However, the fluctuating heritability estimates reflect differences
in handling pre- and post-slaughter and thus highlight difficulties in
measuring tenderness consistently. The low genetic correlation between the 2
muscles (r g = 0.34)
suggests improving overall tenderness of the carcass may be difficult. The
large variance of the slaughter date effect within an abattoir (15% of
the total variance) presents a problem in achieving consistently tender meat.
The paired-paddock model as an agent for change on grazing properties across south-east Australia
Authors: Trompf J. P. , Sale P. W. G.
Published: September 2002

A detailed study was undertaken on the pasture management practices of 146
producers across south-east Australia who participated in the
Grassland’s Productivity Program (GPP) for 3 years between 1993 and
1997. The GPP was an extension program to assist wool producers to develop
skills and gain confidence in their ability to manage more productive pastures
on their farms. The program consisted of 50 farmer groups (200 farmers
participating) spread across the 4 states of South Australia, southern New
South Wales, Victoria and Tasmania. Each farmer established paired-paddocks on
their own property to compare productive pastures with existing pastures.
Productive pastures involve increased rates of fertiliser on pastures
containing productive species, with stocking rate adjusted to consume
available pasture.
After 3 years of involvement in the GPP, there was a whole-farm increase in P
fertiliser use by 6.3 kg P/ha, stocking rates by 2.6 dse/ha and annual
pasture resowing by 0.9% of the farm, when averaged across the 146
participants. The participants were applying the productive pasture technology
to almost a third of their properties in 1997 and the intention was to
increase this to over half of their properties by 2000. The participants also
changed farm management practices as the program effectively developed
management skills. There were increases in the ability to assess pasture
quality and quantity, livestock by weighing or physical assessment, and the
ability to calculate per hectare production and per hectare gross margins. A
high proportion of GPP participants were soil testing (0.92) and spring
lambing (0.72) at the completion of the program.
The results indicated that the adoption of productive pastures was generally
consistent across south-east Australia for pastoral producers who participated
in this program, although south-west Victorian and south-east South Australian
GPP participants did increase whole-farm P application by more than GPP
participants from outside that region. The widespread change in farming
practice was attributed to the additive and interactive effect of the
paired-paddock comparison, the guidance provided by the facilitator, the group
interaction and the skills training. Each of these components of the
paired-paddock model combined to form an effective agent for change to
increase pasture productivity on these grazing properties.
An evaluation of the rationale for fertiliser management of tropical fruit crops
Authors: Huett D. O. , Dirou J. F.
Published: September 2002

Sustainable fertiliser management involves maximising production, preventing
on-site soil degradation and minimising off-site movement of nutrients. In the
past, fertiliser management has been driven by the need to maximise
production. Fertiliser costs are generally less than 10% of the
variable production costs in horticultural enterprises and this has often led
to excessive application of nutrients.
Fertiliser experiments have not generally provided calibrated soil or leaf
test data because of their short-term nature, the biennial or variable
production of many tree crops, their narrow focus and the difficulty in
demonstrating yield responses because tree crops have relatively low rates of
nutrient removal over long periods of time. Nutrient balance is a basically
sound approach to developing fertiliser recommendations and can be easily
estimated from crop nutrient removal data. This approach has been used
successfully for crops such as low-chill stonefruit (Huett and Stewart 1999)
and a simplified approach is presented for passionfruit, mango and avocado
based on nutrient uptake by well-managed, mature, productive orchards.
Macronutrient removal by a 20 t/ha passionfruit crop was (kg/ha) 55
nitrogen (N), 78 potassium (K), 6 phosphorus (P), 6 sulfur (S), 5 calcium (Ca)
and 4 magnesium (Mg). For a 10 t/ha mango crop it was (kg/ha) 11 N, 15
K, 2 P, 1 S, 2 Ca and 2 Mg. For a 10 t/ha avocado crop it was (kg/ha)
41 N, 61 K, 8 P, 4 S, 7 Ca and 8 Mg. Passionfruit, in contrast to tree crops,
is generally a 3-year crop and nutrient uptake by developing leaf, vines and
roots will inflate nutrient uptake by a factor of 2–3. Nutrient losses
due to leaching, runoff and fixation will further inflate fertiliser
requirements. However, the inclusion of these additional factors still means
that nutrient application rates will be substantially less than current
fertiliser recommendations.
Restoring soil fertility of degraded hardsetting soils in semi-arid areas with different pastures
Authors: Chan K. Y. , Bowman A. M. , Smith W. , Ashley R.
Published: September 2002

To evaluate the effectiveness of a pasture phase in restoring soil fertility,
changes in concentration of organic carbon, physical and chemical properties
of degraded hardsetting red soils (Alfisols) were assessed at 3 sites in the
semi-arid central western region of New South Wales 3–4 years after
conversion to different pastures. The pasture species included an annual
grass, ryegrass (Lolium rigidum cv. Wimmera), an annual
legume, barrel medic (Medicago truncatulata cv. Sephi)
as well as a perennial grass, Consol lovegrass
(Eragrostis curvula), and a perennial legume, lucerne
(Medicago sativa cv. Trifecta).
Significant differences in concentration of organic carbon in soils were found
only in the top 0–2.5 cm even after 3–4 years under
perennial pastures. The concentration of organic carbon under annual grass
pasture did not differ from that in the fallow. Corresponding to the organic
carbon concentrations, significant changes in water-stable aggregation
(detectable to 20 cm depth) and hydraulic properties (up to a 5-fold
difference in sorptivity, namely 0.29 mm/h 0.5 under
fallow to 1.42 mm/h 0.5 under lucerne) were observed
under perennial pastures when compared with that of the fallow.
Of the 2 perennial pastures, Consol lovegrass and lucerne were both effective
in promoting soil friability as well as water-stable aggregation. However,
lucerne increased mineralisable nitrogen more than Consol lovegrass (by up to
4.6 times more, equivalent to 11.6 mg/kg in the 0–10-cm layer).
Our results highlight the potential benefits of perennial pastures in
maintaining the quality of the fragile hardsetting soils in the low rainfall
areas. However, due to the slow rate and the restricted depth of improvement
(0–2.5 cm), apart from incorporation of a pasture phase in the
cropping system, soil management that maintains soil organic matter level and
soil structure, namely reduced tillage and stubble retention, should also be
adopted. These findings should be relevant to the management of the
hardsetting soils that occupy 12% of the land area of Australia,
particularly those in the lower rainfall areas.
Factors affecting the adoption of productive pastures by participants in a paired-paddock extension program
Authors: Trompf J. P. , Sale P. W. G. , Graetz B.
Published: September 2002

A survey of 146 pastoral producers across south-eastern Australia was
conducted after they had participated for 3 years in the Grassland’s
Productivity Program. The exit survey, together with earlier surveys, enabled
the changes in whole-farm stocking rate and phosphorus fertiliser use,
management practices, and perceptions of the Grassland’s Productivity
Program, to be determined.
The magnitude of the increases in productivity settings and the increased use
of most recommended management practices were not influenced by either the
facilitator who guided the groups of participants, or by the annual rainfall
for the farm, which varied between 400 and 1000 mm. Path analysis of the
survey data found that changes in productivity settings during
1993–97 did not depend on any one feature of the extension program.
Rather the changes resulted from a hierarchy of interacting effects including
certain initial (1993) and final (1997) management practices, attitudes to the
program and perceived benefits from the program, and situational constraints
such as the availability of suitable soil types on the farm. There were
differences in the significant terms in the regression models that predicted
the change in stocking rate, the change in fertiliser rate, or the combined
variable for both, that was designated as the change index.
Post-weaning growth of cattle in northern New South Wales. 2. Growth pathways of steers
Authors: Dicker R. W. , Ayres J. F. , McPhee M. J. , Robinson D. L. , Turner A. D. , Wolcott M. L. , Kamphorst P. G. , Harden S. , Oddy V. H.
Published: September 2002

This paper describes the post-weaning growth of
Bos taurus and Bos taurus x
Bos indicus-derived steers grazing temperate perennial
pasture in northern New South Wales. These cattle were either autumn weaners
from spring-calving herds in summer rainfall environments, or summer weaners
from autumn-calving herds in winter rainfall environments. Autumn weaners were
grown out on 3 pasture systems: (i) pasture only (P1), (ii) pasture
supplemented in late winter–early spring with formulated pellets of high
protein content (P2), or (iii) pasture supplemented with a nitrogen-fertilised
forage crop (P3) to provide different growth pathways towards entry to the
finishing phase. Over the 3-year study, seasonal liveweight gain on P1 varied
between –0.21 and 1.05 kg/head.day; liveweight gain was generally
low (about 0.5 kg/head.day) in winter and high (about 0.8 kg/head.day)
in spring. Bos taurus autumn weaners achieved feedlot
entry specifications for the domestic market (300 kg liveweight) in 6–8
weeks by the end of winter, and feedlot entry specifications for the export
market (400 kg liveweight) in 17–27 weeks by the end of summer. For
B. taurus x B. indicus-derived
autumn weaners, the period to feedlot entry was 19 and 33 weeks for domestic
and export feedlot entry specifications, respectively. Supplementary feeding
generally increased post-weaning growth in late winter–early spring and
reduced the period to feedlot entry for export steers. Summer weaners were
grown out on pasture in P1, P2 or P3 pasture systems, met domestic feedlot
entry specifications on arrival, but did not reach export feedlot entry
specifications before the onset of winter imposed liveweight stasis. The most
effective grow-out system was based on Bos taurus autumn
weaners with supplementary feeding in winter–spring to overcome the
limitations of the winter feed gap.
Simplified functional model for estimating nitrogen mineralisation and leaching in biosolids-amended soils
Authors: Joshua W. D. , Blasi M. , Osborne G. J.
Published: September 2002

A model was developed to simulate biosolids mineralisation, nitrate leaching
and nitrate uptake by plants. This functional model considers only the end
product of a simplified treatment of the processes that occur without taking
into account their rates. It is specifically structured for the use as a
practical decision support tool for Sydney Water Corporation and other
biosolids users for the beneficial application of biosolids on agricultural
lands without nitrate accretion to groundwater. The model uses fundamental
principles and the relevant concepts from available models to estimate
movement of nitrate down the soil profile.
The model output was compared against data from 3 independent experiments. In
1 experiment, biosolids were used in a sheep-grazing trial and in another,
biosolids were applied to a winter wheat crop. In both cases, nitrate movement
in soil was monitored by soil sampling. In a third experiment, bromide ion was
used as a surrogate for nitrate to trace vertical solute movement under
simulated rainfall. In all 3 experiments, the agreement of model predictions
of nitrogen movement based on the distribution pattern and the position of the
peak concentrations of nitrogen, with measured values was sufficient to
support the validity of the model for nitrate movement in soil after biosolids
application. The model is simple with easily available inputs and is of
sufficient accuracy as a decision support tool in the management of biosolids
application.
Potassium deficiency and its management in a long-term rotation experiment in the south-western slopes New South Wales
Authors: Li G. D. , Helyar K. R. , Conyers M. K. , Cregan P. D. , Cullis B. R. , Poile G. J. , Fisher R. P. , Castleman L. J. C.
Published: September 2002

Potassium (K) deficiency of wheat and pasture species was found at a site in
the south-western slopes of New South Wales. The soil was a subnatric yellow
sodosol. Subterranean clover (Trifolium subterraneum)
was found to be less competitive for K in the soil compared with its
associated grasses. Higher soil K concentrations were required to achieve the
same subterranean clover K concentration in the grass–legume
mixtures than in a subterranean clover monoculture. For wheat
(Triticum aestivum) production, a soil exchangeable K
(Kex ) below 0.25 cmol(+)/kg appeared to be
deficient for the limed treatments, but there was no obvious critical value
for either limed or unlimed treatments. The critical K
exvalues for the grass –legume mixtures could
not be simply specified because the values were affected by competition
between species growing in swards of variable botanical composition. An annual
rate of 20 kg K/ha for the pasture–crop rotations
(50/50%) and 29 kg K/ha for the permanent pastures was
estimated to be sufficient to replenish the K losses from product removal and
animal excreta transferred to campsites at this trial site.
Structural stability of sodic soils in sugarcane production as influenced by gypsum and molasses
Authors: Suriadi A. , Murray R. S. , Grant C. D. , Nelson P. N.
Published: September 2002

The aim of this work was to determine whether molasses, a by-product of sugar
manufacture, alone or combined with gypsum, could improve the structural
stability of sodic soils used for sugarcane production. A Burdekin sandy clay
loam with an exchangeable sodium percentage (ESP) of 7.9, and a Proserpine
loamy sand with an ESP of 18.8 were incubated with molasses (0 and 10 t/ha)
and gypsum (0 and 10 t/ha) for 12 weeks, during which time they were leached 5
times with water (0.5 pore volumes each time). In the Burdekin soil, molasses
and gypsum, either alone or combined, decreased spontaneous clay dispersion
from 2.6 to <0.2 g/kg soil. Mechanical dispersion was reduced from 21.2 to
<0.2 g/kg soil by gypsum alone, and to 14.9 g/kg soil by molasses alone.
Molasses and gypsum both increased wet aggregate stability, with the combined
effect being greatest; the proportion of aggregates >250 μm was 31% in
the control and 71% with molasses + gypsum. Electrical conductivity (EC
1:5) was 0.1 and 1.9 dS/m, pH1:5
in water was 7.7 and 7.1, and ESP was 4.1 and 0.2 in the control and molasses
+ gypsum treatments respectively. In the Proserpine soil, the amounts of
dispersible clay were much less than in the Burdekin soil. The effects of
molasses and gypsum in decreasing spontaneous and mechanical clay dispersion
were similar to those in the Burdekin soil, but less pronounced. Molasses and
gypsum, either alone or combined, improved the structural stability of both
soils by decreasing dispersion and/or slaking. An implication of this work is
that molasses may be a useful ameliorant for sodic soils, either alone or
combined with gypsum.
Sodicity v. yield decline functions for a Vertisol (Grey Vertosol) under border check and raised bed irrigation
Authors: McKenzie D. C. , Bernardi A. L. , Chan K. Y. , Nicol H. I. , Banks L. W. , Rose K. L.
Published: September 2002

The grain yields of 2 soybean crops and a canola crop were related to topsoil
and subsoil properties that are known to affect soil aggregate stability in
water. A broad range of soil conditions was produced by applying gypsum and
lime at various rates to a Vertisol that was naturally sodic throughout the
soil profile. The observations were made under both ‘border check’
and ‘raised bed’ irrigation.
Soil factors that influence dispersibility and crop growth were considered as
part of a stepwise regression analysis. For the 2 soybean crops under border
check irrigation, surface exchangeable sodium percentage (ESP) explained 72
and 63%, respectively, of the grain yield variation. For the canola crop that
followed, a combination of pH, ESP and electrical conductivity (in that order)
explained 75% of the variation in grain yield.
Grain yields for the 3 crops declined as the soil became more sodic,
particularly on the flat border check area. For soybeans (flat area), the
critical values of ESP at which surface sodicity caused a 50% yield decline
(ESP50) were strongly influenced by the post-planting
climatic conditions. When there was heavy rain just after germination of the
soybean seedlings, the ESP50 value was 8.6. The more
sodic areas developed a thick crust that impeded seedling emergence. However,
in the following year, when conditions remained dry after planting, the
ESP50 value was 10.7.
Under bed irrigation, the influence of ESP on yield was only minor after the
first year of cropping. There was evidence of soil structure improvement from
salt that was deposited in the beds via the irrigation water. Subsoil chemical
properties that affect structural stability had more of an influence on crop
yield under beds than under the flat areas.
Groundwater use in forage production: the effect of salinesodic irrigation and subsequent leaching on soil sodicity
Authors: Burrow D. P. , Surapaneni A. , Rogers M. E. , Olsson K. A.
Published: September 2002

Lucerne plots were irrigated with waters of electrical conductivity (EC) =
0.1, 0.8, 2.5, 4.5 and 7.5 dS/m for the summers of 1991–92 to
1994–95. Within those 4 years, soils were sodified at irrigation
treatment salinities greater than 0.8 dS/m. Subsequent leaching of salts with
channel water (EC = 0.1 dS/m) and rain water (1995–97) reduced surface
soil sodicity but not subsoil sodicity. This resulted in increased dispersed
clay in the subsoil. Clay dispersion was best explained by exchangeable sodium
percentage (ESP) and Mg in topsoils, and by ESP and salinity (TCC or Cl) in
subsoils. Ponding of water, following a 46 mm spring rainfall event, increased
with ESP of topsoils. Short-term millet yields over the 1996–97 summer
were not affected by soil sodicity despite channel water irrigation. However,
cumulative pasture yields over 1997 decreased by 25% between high and low
levels of residual soil sodicity.