bluuebunny/crossref_metadata_2025 huggingface dataset:
Substrate recognition and transport by multidrug resistance protein 1 (ABCC1)
Authors: Deeley Roger G. , Cole Susan P.C.
Published: January 2006

Multidrug resistance protein (MRP) 1 belongs to the ‘C’ branch of the ABC transporter superfamily. MRP1 is a high‐affinity transporter of the cysteinyl leukotriene C4and is responsible for the systemic release of this cytokine in response to an inflammatory stimulus. However, the substrate specificity of MRP1 is extremely broad and includes many organic anion conjugates of structurally unrelated endo‐ and xenobiotics. In addition, MRP1 transports unmodified hydrophobic compounds, such as natural product type chemotherapeutic agents and mutagens, such as aflatoxin B1. Transport of several of these compounds has been shown to be dependent on the presence of reduced glutathione (GSH). More recently, GSH has also been shown to stimulate the transport of some conjugated compounds, including sulfates and glucuronides. Here, we summarize current knowledge of the substrate specificity and modes of transport of MRP1 and discuss how the protein may recognize its structurally diverse substrates.
Spatial variation in abundance and catch composition of Cancer pagurus in Norwegian waters: biological reasoning and implications for assessment
Authors: Woll Astrid K. , van der Meeren Gro I. , Fossen Inge
Published: January 2006

The edible crab (Cancer pagurus), which is abundant along the Norwegian coast north to Troms County, has been exploited in Norway since the start of the 20th century. The main fishery is in Mid-Norway and Helgeland (63°–67°N), which together land 75% of the Norwegian catch. The fishery is regulated by season, minimum legal size, and the discarding of soft or ovigerous females. Catches have never been systematically described, so this study presents data collected over 4 years by a reference fleet of professional fishers reporting the catch from four standardized trial traps set among their ordinary traps. Catch rate, catch composition, and size distribution from Mid-Norway/Helgeland are compared with the smaller crab fishery in Rogaland (59°N) and with new crab grounds off Vesterålen (69°N). Local variations in size and sex composition between and within region seemed partly to be caused by differences between exposed and sheltered regions, and between heavily and newly exploited grounds. Size distribution is used as an indicator to determine a suitable sampling strategy. The most efficient survey design is seemingly the collection of relatively small samples from many boats to reduce the between-vessel component of variation. A suggested strategy to obtain an abundance index would be to collect daily catch rates from all commercial landings.
Using global genome approaches to address problems in cod mariculture1
Authors: Goetz Frederick W. , McCauley Linda , Goetz Giles W. , Norberg Birgitta
Published: January 2006

A number of techniques, including expressed sequence tag (EST) analysis, serial analysis of gene expression, and micro-arrays, are available to study the global expression and regulation of genes. Many of these techniques are being used for intensively reared fish such as trout, salmon, and catfish to study genes involved in growth, reproduction, and health. In contrast, relatively little is known about the composition and regulation of transcriptomes in gadids. However, several bottlenecks in cod mariculture might benefit from the discovery and analysis of genes involved in reproduction, growth, and disease. As a result, we have begun EST analysis of genes in the cod ovary. Complimentary DNA (cDNA) libraries of cod ovaries taken from females at oocyte final maturation and ovulation have been constructed, and 1361 ESTs have been analysed. As expected, several oocyte-related genes were observed, including various zona pellucida egg membrane proteins. However, pivotal cell cycle regulators such as cyclins, genes involved in the regulation of apoptosis such as the Bcl-2-related ovarian killer protein, and hormone receptor components were also observed. Finally, a cDNA for a potential novel cod antifreeze protein was observed 12 times, suggesting the existence of a cod egg-specific antifreeze protein.
Monolayer alignment on azobenzene surfaces during UV light irradiation: Analysis of optical polarized absorption measurement results and theoretical treatment
Authors: Zakharov A. V. , Taguchi Dai , Manaka Takaaki , Iwamoto Mitsumasa
Published: January 2006

The influence of the charge separation during the trans-cis conformational change on the surface of azobenzene 6Az10PVA monolayer on the polar liquid-crystal monolayer film, such as 4-n-pentyl-4′-cyanobiphenyl(5CB), is investigated. The effective anchoring energy (in the Rapini-Papolar form) is phenomenologically described in the framework of the molecular model, which takes into account the interaction between the surface polarization and surface electric field, for number of conformational states of the boundary surface. It is shown, using the experimental data for the voltage across the 6Az10PVA+5CB film, provided by the surface-potential technique, that the charge separation during the conformational changing, caused by the UV irradiation, may lead to changing of the surface alignment of liquid-crystalline molecules. The influence of the photoisomerization process on the orientational order parameter S2(t) using the optical polarized absorption measurement is also investigated.
Proton dynamics in lithium-ammonia solutions and expanded metals
Authors: Thompson Helen , Skipper Neal T. , Wasse Jonathan C. , Spencer Howells W. , Hamilton Myles , Fernandez-Alonso Felix
Published: January 2006

Quasielastic neutron scattering has been used to study proton dynamics in the system lithium-ammonia at concentrations of 0, 4, 12, and 20 mole percent metal (MPM) in both the liquid and solid (expanded metal) phases. At 230 K, in the homogenous liquid state, we find that the proton self-diffusion coefficient first increases with metal concentration, from 5.6×10−5cm2s−1 in pure ammonia to 7.8×10−5cm2s−1 at 12 MPM. At higher concentrations we note a small decrease to a value of 7.0×10−5cm2s−1 at 20 MPM (saturation). These results are consistent with NMR data, and can be explained in terms of the competing influences of the electron and ion solvation. At saturation, the solution freezes to form a series of expanded metal compounds of composition Li(NH3)4. Above the melting point, at 100 K, we are able to fit our data to a jump-diffusion model, with a mean jump length (l) of 2.1 Å and residence time (τ) of 3.1 ps. This model gives a diffusion coefficient of 2.3×10−5cm2s−1. In solid phase I (cubic, stable from 88.8 to 82.2 K) we find that the protons are still undergoing this jump diffusion, with l=2.0Å and τ=3.9ps giving a diffusion coefficient of 1.8×10−5cm2s−1. Such motion gives way to purely localized rotation in solid phases IIa (from 82.2 to 69 K) and IIb (stable from 69 to 25 K). We find rotational correlation times (τrot) of the order of 2.0 and 7.3 ps in phases IIa and IIb, respectively. These values can be compared with a rotational mode in solid ammonia with τrot∼2.4ps at 150 K.
Density-functional geometry optimization of the 150 000-atom photosystem-I trimer
Authors: Canfield Peter , Dahlbom Mats G. , Hush Noel S. , Reimers Jeffrey R.
Published: January 2006

We present a linear-scaling method based on the use of density-functional theory (DFT) for the system-wide optimization of x-ray structural coordinates and apply it to optimize the 150 000 atoms of the photosystem-I (PS-I) trimer. The method is based on repetitive applications of a multilevel ONIOM procedure using the PW91∕6-31G(d) DFT calculations for the high level and PM3 for the lower level; this method treats all atoms in the structure equivalently, a structure in which the majority of the atoms can be considered as part of some internal “active site.” To obtain a realistic single structure, some changes to the original protein model were necessary but these are kept to a minimum in order that the optimized structure most closely resembles the original x-ray one. Optimization has profound effects on the perceived electronic properties of the cofactors, with, e.g., optimization lowering the internal energy of the chlorophylls by on average 53kcalmol−1 and eliminates the enormous 115kcalmol−1 energy spread depicted by the original x-ray heavy-atom coordinates. A highly precise structure for PS-I results that is suitable for analysis of device function. Significant qualitative features of the structure are also improved such as correction of an error in the stereochemistry of one of the chlorophylls in the “special pair” of the reaction center, as well as the replacement of a water molecule with a metal cation in a critical region on the C3 axis. The method also reveals other unusual features of the structure, leading both to suggestions concerning device functionality and possible mutations between gene sequencing and x-ray structure determination. The optimization scheme is thus shown to augment the molecular modeling schemes that are currently used to add medium-resolution structural information to the raw scattering data in order to obtain atomically resolved structures. System-wide optimization is now a feasible process and its use within protein x-ray data refinement should be considered.
Theoretical study of one-, two-, and three-photon absorption properties for a series of Y-shaped molecules
Authors: Lin Na , Zhao Xian , Yang Jia-Xiang , Jiang Min-Hua , Liu Ji-Cai , Wang Chuan-Kui , Shi Wei , Meng Juan , Weng Jun
Published: January 2006

In this paper, the equilibrium geometries, one-, two-, and three-photon absorption properties, and the transition nature of a series of Y-shaped molecules which possess an imidazole-thiazole core have been theoretically studied by using the parametrization model 3 and Zerner’s intermediate neglect of differential overlap methods. Our calculated results have confirmed the experimental findings that the investigated molecules are all promising multiphoton absorption materials and both the two-photon absorption and the three-photon absorption cross sections are seriatim increscent along with the increase of the electron-donor strength. The nonlinear optical phenomenon originates from the intramolecular charge transfer within the π-conjugated system. The calculated results indicate that the heterocyclic core increases the two- and three-photon absorption cross sections due to its π-excessive nature. So it can provide more free electrons to enlarge the charge transfer within the molecule system. In addition, the design of Y shape and the sulfonyl-based electron-accepting group play a part in the enhancement of multiphoton absorption. It is notable that molecules with heterocyclic core will provide favorable condition for multiphoton absorption applications.
A fragment molecular-orbital–multicomponent molecular-orbital method for analyzing H∕D isotope effects in large molecules
Authors: Ishimoto Takayoshi , Tachikawa Masanori , Nagashima Umpei
Published: January 2006

We have developed a fragment molecular orbital (FMO)–multi-component MO (MC_MO) method to analyze isotope effect due to differences between the quantum effects of protons and deuterons for large molecules such as proteins and DNA. The FMO-MC_MO method enables the determination of both the electronic and the protonic (deuteronic) wave functions simultaneously, and can directly express isotope effects, including coupling effects between nuclei and electrons. In our calculations of two polyglycines, which serve as prototypes for biological molecules, by this method, we clearly observed the geometrical relaxation induced by the H∕D isotope effect in the intramolecular hydrogen bonding portions of the molecules. The H∕D isotope effect on the interfragment interaction energy, including that of the hydrogen bonding parts, was also demonstrated: the hydrogen bond was weakened by replacement of hydrogen with deuterium. We also developed electrostatic potential approximations for use in the FMO-MC_MO calculations, and the accuracy of the energy differences induced by the isotope effect was independent of the approximation level of the FMO-MC_MO. Our results confirmed that the FMO-MC_MO method is a powerful tool for the detailed analysis of changes in hydrogen bonding and interaction energies induced by the H∕D isotope effect for large biological molecules.
Energy of excitons in CuInS2 single crystals
Authors: Yakushev M. V. , Mudryi A. V. , Victorov I. V. , Krustok J. , Mellikov E.
Published: January 2006

High-quality single crystals of CuInS2, grown by the traveling heater method in an indium solvent, were characterized using photoluminescence (PL) and reflectance (RF) at temperatures from 4.2to300K. A number of well-resolved sharp excitonic peaks have been observed in the near-band-edge region of the PL and RF spectra at 4.2K. The lines at 1.536 and 1.554eV in the RF spectra were associated with A and (B,C) free-excitonic transitions, respectively. In the PL spectra the A exciton revealed a well-resolved splitting into two peaks at 1.5348 and 1.5361eV assigned to the lower and upper branches of exciton polariton, respectively. Other sharp lines were assigned to excitons bound at shallow impurities. The experimental temperature variation of the band gap was analyzed using the Bose–Einstein model. Two deeper bands in the PL spectra were identified as free-to-bound optical transitions followed by phonon replicas.
Effect of ferroelectric layers on the magnetocapacitance properties of superlattices-based oxide multiferroics
Authors: Singh M. P. , Prellier W. , Mechin L. , Raveau B.
Published: January 2006

A series of superlattices composed of ferromagnetic La0.7Ca0.3MnO3 (LCMO) and ferroelectric/paraelectric Ba1−xSrxTiO3 (0⩽x⩽1) were deposited on SrTiO3 substrates using pulsed laser deposition. Magnetotransport properties of the films reveal a ferromagnetic Curie temperature in the range of 145–158K, and negative magnetoresistance as high as 30%, depending on the type of ferroelectric layers employed for their growth (i.e., “x” value). Ferroelectricity at temperatures ranging from 55Kto105K is also observed, depending on the barium content. More importantly, the multiferroic nature of the film is determined by the appearance of negative magnetocapacitance, which is maximum around the ferroelectric transition temperature (3% per tesla). These results are understood based on the role of the ferroelectric/paraelectric layers and strains in inducing the multiferroism.
Photoluminescence and cathodoluminescence analyses of GaN powder doped with Eu
Authors: Wu Huaqiang , Poitras Carl B. , Lipson Michal , Spencer Michael G. , Hunting Janet , DiSalvo Francis J.
Published: January 2006

A high yield process to produce gallium nitride (GaN) powder doped with europium (Eu) is presented. Eu is in situ incorporated into GaN powder through the reaction between a molten alloy of Ga and Eu along with NH3 at 1000 °C using Bi as a wetting agent. This procedure provides a method to produce a GaN:Eu phosphor with high yield and low cost. Room temperature photoluminescence (PL) measurements are studied on GaN:Eu powders with different Eu concentrations. The maximum PL intensity is obtained at a Eu concentration of 1.25 at. %. Cathodoluminescence spectra at room temperature exhibit many detailed transitions in the 530–630 nm range.
Phase-change magnetic memory effect in cation-deficient iron sulfide Fe1−xS
Authors: Takayama Tomohiro , Takagi Hidenori
Published: January 2006

We report the discovery of magnetic memory effect in cation-deficient iron sulfide Fe1−xS. This nonstoichiometric sulfide shows a transition from a ferrimagnet to an antiferromagnet induced by an order-disorder transition of cation defects. The magnetic properties of Fe0.92S, at the critical composition for the order-disorder transition, were reliably controlled by the use of appropriate heat treatments; the slow-cooled sample showed ferrimagnetism with a spontaneous magnetization, while the quenched samples displayed superparamagnetic behavior without hysteresis. We propose that this material can be used as part of a nonvolatile phase-change memory device.
Decoration of buried surfaces in Si detected by positron annihilation spectroscopy
Authors: Brusa R. S. , Macchi C. , Mariazzi S. , Karwasz G. P. , Egger W. , Sperr P. , Kögel G.
Published: January 2006

The terminations of buried surfaces of two different cavity types (nano- and microcavities) produced in the same He+–H+ co-implanted p-type Si (100) sample annealed at 900°C, are studied and characterized by positron annihilation spectroscopy. The characterization was carried out by means of three complementary positron techniques: Doppler broadening and coincidence-Doppler broadening spectroscopy with a continuous slow positron beam, and lifetime spectroscopy with a pulsed slow positron beam. It was found that the nanocavities have a pristine surface of Si, while the surfaces of the microcavities, formed below protruding blisters, are oxygen decorated. This case study opens the interesting use of the positron spectroscopy tool in the topical subject of empty space for microelectronics applications.
Early onset of parturition induced by acute alcohol exposure in C57BL/6J mice: role of uterine PGE and PGF2a
Authors: Cook J. L. , Randall C. L.
Published: January 2006

These studies were designed to determine the effect of acute alcohol treatment
on gestational length and to probe for a mechanism underlying alcohol-induced
early onset of parturition (EOP) in mice. Experiment 1:
alcohol increases the incidence of EOP. Pregnant C57BL/6J mice were given
alcohol (0, 4, 5 or 6 g kg -1 , i.g.) on Gestational Day
(GD) 10, 15, 16, 17 or 18. Deliveries were monitored every 6 h from GD 18.
Results indicated that 6 g kg -1 alcohol treatment on GD
17 or 18 increased the incidence of EOP. Experiment 2: prostaglandins (PGs)
play roles in parturition. The purpose of Experiment 2
was to determine whether PGs mediate alcohol-induced EOP in mice. The results
indicated that pretreatment on GD 17 with aspirin, a prostaglandin synthesis
inhibitor, prevented alcohol-induced EOP. These data suggest that
alcohol-induced EOP in mice may be mediated by PGs. Experiment 3: PGs are
influenced by alcohol and are triggers of labour.
Experiment3 measured uterine PGs
associated with the onset of alcohol-induced EOP in mice. Alcohol increased
uterine PGE and PGF2a , with PGE levels higher than
control before labour, and elevated PGF2a levels
correlating with labour. Changes in gestational length have important
implications for pregnancy outcome, as well as for normal fetal growth and
development.
The follicle-stimulating hormone β-subunit gene of the common brushtail possum (Trichosurus vulpecula): analysis of cDNA sequence and expression
Authors: Lawrence Stephen B. , Vanmontfort Dominique M. , Tisdall David J. , McNatty Kenneth P. , Fidler Andrew E.
Published: January 2006

Reverse transcription–PCR has been used to obtain a cDNA sequence from
the follicle-stimulating hormone (FSH) β-subunit gene of the Australian
brushtail possum (Trichosurus vulpecula). Comparisons of
the possum FSHβ-mRNA coding region nucleotide sequence with that of six
eutherian mammal homologues reveals a mean percent identity of
77·3% and 76·8% at the nucleotide and predicted
amino acid-sequence levels respectively. Furthermore, the predicted amino acid
sequence of the possum FSHβ mature protein shows evolutionary conservation
of twelve cysteine residues and two potential N-linked
glycosylation sites. The protein lacks the CAGY motif present in most reported
glycoprotein β-subunit sequences. The translation termination codon and
consensus polyadenylation sequence overlap, a feature observed in other
mammalian FSHβ genes. Northern hybridization of total RNA from adult
female possum pituitary revealed three hybridizing transcripts of
approximately 2·8, 1·2 and 0·5 kb which may arise from
utilizing alternative polyadenylation signals. In situ
hybridization localized the FSHβ transcripts to a sub-population of
anterior pituitary cells interpreted as being gonadotropes. In summary the
results indicate considerable evolutionary conservation of the structure of
the FSH b-subunit gene between the marsupial and eutherian mammalian lineages.
Intracellular pH increase accompanies parthenogenetic activation of porcine, bovine and murine oocytes
Authors: Ruddock Nancy T. , Macháty Zoltán , Prather Randall S.
Published: January 2006

Although an intracellular pH (pH i ) increase at the
time of fertilization is necessary for activation of the sea urchin egg,
recent reports in the mouse and rat have indicated that there is not a
pHi increase during fertilization or during 7%
ethanol activation in the mouse. It has been suggested that mammals may have
lost the need for a pH i increase at the time of
fertilization and the present study reports significant pH
i changes during parthenogenetic activation of porcine
IVM oocytes, as well as pH i responses to activation in
bovine and murine oocytes. Transient intracellular pH changes were found
during porcine oocyte activation when using 7% ethanol and with 50 or
100 M calcium ionophore (A23187). Treatment with 200 M thimerosal resulted in
an increase in pH i after a delay of approximately 12
min. Murine oocytes showed a significant increase during activation with
7% ethanol and A23187 as well as during prolonged exposure to
thimerosal. Bovine oocytes exhibited an increase in pH i
only when activated with 50 or 100 M A23187. The final set of experiments
aimed to determine whether the porcine oocyte has mechanisms to alleviate
induced acidic and alkaline challenges. Both acidic (~20 mM acetic acid) and
alkaline (~30 mM ammonium chloride) challenges caused significant changes in
pH i that porcine IVM oocytes were capable of recovering
from within 35 min. Future studies will focus on determining which of the
mechanisms is producing the pH i increase at the time of
parthenogenetic activation in the porcine oocyte.
The interaction of fresh and frozen-thawed ram spermatozoa with oviducal epithelial cells in vitro
Authors: Gillan L. , Evans G. , Maxwell W. M. C.
Published: January 2006

In order to investigate the interaction of fresh and frozen–thawed
spermatozoa with oviduct epithelial cells, spermatozoa were co-incubated with
ovine oviduct epithelial cell monolayers (OECM) derived from either complete
oviducts, at any stage of the oestrous cycle (Experiments 1 and 2), or from
different regions of the oviduct at different stages of the cycle (Experiment
3). Fresh and frozen—thawed spermatozoa displayed different patterns
of binding to, and release from, the OECM. Frozen—thawed spermatozoa
immediately bound to the complete oviduct OECM and were released after 2 h. A
small proportion of fresh spermatozoa bound immediately, increasing to a
maximum after 2 h, and were gradually released thereafter. When only the cells
that were released from the OECM were observed by chlortetracycline staining
in Experiment 2, it was found that the presence of an OECM increased the
number of capacitated fresh spermatozoa while decreasing the number of
capacitated frozen–thawed spermatozoa. Overall, the OECM advanced the
membrane state of both types of spermatozoa from uncapacitated to
acrosome-reacted. Fresh and frozen—thawed spermatozoa bound to OECM
derived from the cells of the isthmus and the ampulla in similar proportions.
However, more spermatozoa were capacitated when incubated with OECM derived
from isthmic rather than ampullary cells. Higher proportions of fresh
spermatozoa bound to, and were acrosome-reacted following incubation with OECM
derived from post- rather than pre-ovulatory tracts. Such differences were not
observed for frozen—thawed spermatozoa. The findings reported in
this study show that fresh and frozen—thawed spermatozoa behave
differently when in contact with oviduct cells in vitro.
This may be a consequence of the more advanced membrane state of the frozen
spermatozoa upon thawing.
Diminished PGE2 content, enhanced PGE2 release and defects in 3H-PGE2 transport in embryos from overtly diabetic rats
Authors: Jawerbaum Alicia , Gonzalez Elida T. , Sinner Débora , Pustovrh Carolina , White Verónica , Gimeno Martha A. F.
Published: January 2006

Diminished PGE2 levels in diabetic embryos are related
to the development of malformations, and thus the aim of the present study was
to determine whether PGE2 levels are modified in rat
embryos cultured in diabetic serum during organogenesis, and if
PGE2 content and release, and
3H-PGE2 uptake and release, are
altered in incubated diabetic embryos. Rats were made diabetic by
steptozotocin (60 mg kg–1) before mating. Control
rat embryos cultured for 24 h (explantation Day 9) in the presence of diabetic
serum showed diminished PGE2 levels. When Day 10
diabetic embryos were incubated, embryo PGE2 levels were
lower, but the PGE2 released to the incubation media was
much higher than in controls. Uptake of
3H-PGE2 by diabetic embryos was
initially enhanced (5–10 min), then reached similar levels to controls
(20–100 min). Release of
3H-PGE2 previously incorporated
during a 60-min incubation was greater in diabetic embryos than in controls.
These results show diminished PGE2 content in both
diabetic and normal embryos cultured in the presence of diabetic serum, but
suggest that diabetic embryos have the capability to produce and release high
levels of PGE2. The enhanced release of
PGE2 is probably the result of transport abnormalities,
and leads to the elevated PGE2 concentrations found in
the incubating medium and to the diminished intraembryonic
PGE2 levels that alter embryonic development.
Freezability of boar spermatozoa is improved by exposure to 2-hydroxypropyl-beta-cyclodextrin
Authors: Zeng WenXian , Terada Takato
Published: January 2006

The influence of 2-hydroxypropyl-beta-cyclodextrin (HBCD) exposure on
post-thaw spermatozoa prior to freezing using acrosome integrity and the
parameters of motility was studied. Acrosomal status was monitored by means of
FITC-labelled peanut agglutinin, and the motility parameters were assessed
using a computer-assisted sperm motility analysis (CASA) system. The
spermatozoa were exposed to HBCD over a period of 3 h, during which the cells
were slowly cooled from 25 to 5˚C, and then frozen into pellets. The
percentage of frozen–thawed spermatozoa with intact acrosomes in 40 mM
HBCD group was approximately three-fold higher than that of the control. The
motility and progressive motility values of the frozen–thawed
spermatozoa were found to increase significantly with increased HBCD
concentrations. On the other hand, further addition of cholesterol-3-sulfate
to the BF5 extender containing 20 mM HBCD resulted in a drastic decrease in
the percentage of spermatozoa with intact acrosomes, and decreased motility
and progressive motility, suggesting that cholesterol-sulfate probably
counter-acted the protective action of HBCD. In conclusion, the results of the
present study indicate that HBCD protected boar spermatozoa against
freeze–thaw damage, possibly by means of stimulating the efflux of
membrane cholesterol.
Heterogeneous osmotic behaviour in boar sperm populations and its relevance for detection of changes in plasma membrane
Authors: Petrunkina A. M. , Töpfer-Petersen E.
Published: January 2006

The spermatozoa of most mammals behave as ‘perfect osmometers’.
The volume response to osmolality obeys the Boyle–Van’t Hoff
relationship (i.e. volume changes are determined by the osmotically active
fraction of the cell volume (solids and water)). Most evaluations of osmotic
sperm cell behaviour have been based on the mean volume of the cell
population. In the present study, both mean and modal volumes of samples of
sperm were evaluated. Both mean and modal volumes responded to environmental
osmolality via the Boyle–Van’t Hoff relationship; however, the
modal volume showed a more sensitive response than the mean volume. This was
confirmed for both ejaculated and epididymal spermatozoa. After incubation
under capacitating conditions, the difference in modal and mean volume
response of ejaculated sperm was considerably diminished and, in epididymal
sperm, completely abolished. The sperm osmotic behaviour was still consistent
with the Boyle–Van’t Hoff equation, but the apparent osmotically
inactive modal cell volume decreased after exposure to capacitating conditions
in both ejaculated and epididymal sperm samples. The changes in epididymal
sperm were more intensive. Due to its enhanced sensitivity to environmental
osmolality and incubation under capacitating conditions, the modal volume
could be used as a parameter for evaluating sperm population response, such as
for detecting environmentally or cryopreservation-induced membrane changes.
Oestrone sulfate commences an increase around 50 days of gestation in bovine peripheral blood
Authors: Hirako Makoto , Takahashi Hitomi , Takahashi Toru
Published: January 2006

The objective of this study was to determine the peripheral plasma
concentration of oestrone sulfate during early gestation in the cow with a
sensitive assay system. Five Holstein heifers were inseminated on oestrus and
bled from the jugular vein at regular intervals until 100 days of gestation.
Oestrone sulfate, oestrone and oestradiol-17β in blood plasma were
extracted with a reverse-phase cartridge and each measured by specific
radioimmunoassay. Oestrone sulfate in bovine circulation started to increase
around 50 days of gestation, whereas oestrone and oestradiol-17β remained
at basal concentrations for 80 days. The plasma concentration of oestrone
sulfate increased gradually and linearly from 50 days of gestation, and was
drastically elevated after 80 days of gestation before the increase in
unconjugated oestrogens. The rate of increase from 80 to 100 days was the
greatest for oestrone sulfate concentration among all oestrogens. These
results suggest that plasma oestrone sulfate concentration could be a useful
indicator of pregnancy within the first trimester of gestation in the cow.
Functional capacity and fertilizing longevity of frozen-thawed scimitar-horned oryx (Oryx dammah) spermatozoa in a heterologous in vitro fertilization system
Authors: O'Brien Justine K. , Roth Terri L.
Published: January 2006

This study was conducted to determine if cryopreservation and thawing reduces
the quality of scimitar-horned oryx spermatozoa and thus might be responsible
for sub-optimal artificial insemination (AI) efficiency. Functional capacity
of frozen–thawed oryx spermatozoa was compared in a heterologous bovine
in vitro fertilization (IVF) system after being prepared
by four methods. Fertilizing longevity was also assessed after thawing and
pre-incubating spermatozoa for 12 or 24 h before IVF. Sperm characteristics
(viability, morphology, acrosomal and capacitation status) were superior for
samples prepared by Percoll centrifugation and standard swim-up compared with
microdrop swim-up and wash methods. Regardless of variation in sperm
characteristics over time, fertilization success and embryo development were
high and did not differ among treatments. Fertilization and cleavage success
for spermatozoa pre-incubated for 12 h before IVF were comparable with that
achieved with non-incubated spermatozoa. Even 24 h after thawing, spermatozoa
were capable of fertilizing oocytes, but percentage fertilization and embryo
cleavage were significantly lower than for spermatozoa pre-incubated for 12 h.
Overall, functional capacity of oryx spermatozoa after thawing appears
comparable with that of domestic bull spermatozoa. When used for AI,
frozen—thawed oryx spermatozoa should be capable of fertilizing
oocytes in females ovulating 12 or even 24 h after insemination, providing
sperm transport mechanisms are adequate. The functional capacity and
fertilizing longevity of oryx sperm after thawing is high, and therefore
unlikely to be responsible for decreased AI efficiency in the scimitar-horned
oryx.
Allocation of cells to the inner cell mass and trophectoderm of 3/4 mouse embryos
Authors: Somers GR , Trounson AO , Wilton LJ
Published: January 2006

The allocation of cells to the inner cell mass (ICM) and trophectoderm (TE) was investigated at 6-h intervals from 78 h to 102 h after hCG injection in 3/4 mouse embryos to determine the effect of removal of a single blastomere at the 4-cell stage on early differentiation. The procedures used to produce 3/4 embryos had little effect on embryo development. Embryos that had a single blastomere removed and then re-aggregated (RA embryos) had the same total number of cells as untreated (UT) embryos except at 78 h (P less than 0.05) and 102 h (P less than 0.01) post hCG where there were slightly less cells in RA embryos. Three-quarter embryos always had significantly fewer cells than RA embryos (P less than 0.001), with an average of 74% of the total cell number of RA embryos. As expected, 3/4 embryos always had significantly fewer cells in the ICM and TE compared with RA embryos (P less than 0.001). However, the ICM:TE ratio was also significantly lower in 3/4 embryos compared with RA embryos at 84, 96, and 102 h post hCG, indicating that the allocation of cells to the ICM and TE was disturbed. The ICM:TE ratio of 3/4 embryos could not be manipulated if either an early- or late-dividing blastomere was selectively biopsied at the 4-cell stage; this suggests that the known preferential contribution of an early-dividing blastomere to the ICM is not cell autonomous.
Effects of bromocriptine at parturition in the tammar wallaby, Macropus eugenii
Authors: Fletcher TP , Shaw G , Renfree MB
Published: January 2006

Female tammar wallabies were treated with the dopamine agonist bromocriptine at the end of pregnancy to suppress the peripartum pulse of plasma prolactin. The animals were subsequently observed, and a series of blood samples taken to define the hormonal profiles before and immediately after parturition. Birth was observed in 4/5 control animals and occurred in 8/9 bromocriptine-treated animals. The peripartum peak in plasma PGFM concentrations was not affected by bromocriptine although the pulse of prolactin normally seen at parturition was completely abolished. The timing of luteolysis was apparently unaffected, as plasma progesterone concentrations fell similarly in both treated and control animals immediately after parturition. However, all of the neonates of the bromocriptine-treated animals died within 24 h, possibly because of a failure to establish lactation. Subsequent onset of post-partum oestrus was delayed or absent both in control and in bromocriptine-treated animals, suggesting that the frequent blood sampling and disturbances in the peripartum period interfered with these endocrine processes. It is concluded that both prolactin and prostaglandin can induce luteolysis in the pregnant wallaby, but that the normal sequence of events results from a signal of fetal origin inducing a prostaglandin release from the uterus, which in turn releases a pulse of prolactin that induces a progesterone decline.
Muscle growth, cell number, type and morphometry in single and twin fetal lambs during mid to late gestation
Authors: McCoard S. A. , McNabb W. C. , Peterson S. W. , McCutcheon S. N. , Harris P. M.
Published: January 2006

Muscle growth, myofibre number, type and morphometry were studied in large
hindlimb muscles of single and twin fetal lambs during mid to late gestation.
Placental insufficiency, evident by lower total placentome weight and number
per fetus, resulted in reduced fetal weights from 100 to 140 days gestation in
twins compared with singletons (at 140 days: 5016 108 g
v. 5750 246 g, respectively;
P<0.05). However, competition between littermates did
not consistently reduce muscle mass (15–22%) until 140 days
gestation. Apparent myofibre number increased with age, indicating that the
full complement of myofibres in some large hindlimb muscles may be achieved
during early postnatal life. Litter size did not impact on apparent myofibre
number in the semitendinosus,
plantaris or gastrocnemius
muscles. However, a transient effect on myofibre number in the
adductor femoris muscle was observed from 80–120
days gestation. The phenotypic maturation of myofibres was unaffected by
increasing litter size. Smaller muscle mass in twins was associated with
smaller myofibre cross-sectional area in the
semitendinosus, adductor femoris
and gastrocnemius muscles at 140 days gestation. A
similar trend was observed for the plantaris muscle. These results indicate
that while competition between littermates for nutrients in late gestation can
impact on both fetal and muscle mass, the fetus has the capacity to buffer
against the effects of restricted nutrient supply on myofibre hyperplasia and
phenotypic maturation, but myofibre hypertrophy is compromised.
Cardiovascular and hypothalamic-pituitary-adrenal axis development in late gestation fetal sheep and young lambs following modest maternal nutrient restriction in early gestation
Authors: Hawkins P. , Steyn C. , McGarrigle H. H. G. , Calder N. A. , Saito T. , Stratford L. L. , Noakes D. E. , Hanson M. A.
Published: January 2006

The effect of a 15% reduction in maternal nutrition for the first 70
days of gestation on cardiovascular and
hypothalamic–pituitary–adrenal (HPA) axis responses to
administration of corticotropin releasing hormone (CRH) + arginine
vasopressin (AVP) was studied at 128 0.7 days gestation in fetal sheep and
postnatally, at 85 4.5 days in young lambs. The effect on the fetal
cardiovascular response to acute hypoxaemia was also examined. Under basal
conditions, fetal heart rate (FHR) was reduced
(P<0.05) and basal femoral artery vascular resistance
(FVR) was increased (P<0.05) in fetuses of
dietary-restricted (R) ewes compared with controls (C). Fetal mean arterial
pressure (MAP) was similar in both groups. Femoral artery vascular resistance
was also greater during hypoxaemia in R fetuses compared with C fetuses
(P<0.05), suggesting that chemoreflex mechanisms were
augmented in the R group. The fetal ACTH response to CRH + AVP was
similar in both groups. However, cortisol responses to CRH + AVP were
smaller in R fetuses compared with C fetuses
(P<0.05). Postnatally, basal MAP
(P<0.05), and ACTH (P<0.01)
and cortisol (P<0.001) responses were greater in R
lambs compared with C lambs. It was concluded that modest maternal
undernutrition during pregnancy alters development of the cardiovascular
system, producing elevated blood pressure in postnatal life. Development of
the HPA axis is also altered, with reduced activity during fetal life, but
increased activity postnatally. The data suggest that the HPA axis may play a
role in mediating the elevation of MAP in R lambs.
The Genus Podaxis (Gasteromycetes) in Australia with a Description of a New Species from Termite Mounds
Authors: Lenz M. , Priest M.J.
Published: January 2006

In Australia, two species of Podaxis are recognised based
on spore morphology. The species occurring on soil is recognised as
P. pistillaris (L. : Pers.) Fr. and the name
P. beringamensis sp. nov. is proposed for a new species
occuring on termite mounds in Australia.
Podaxis carcinomalis (L.f. : Pers.) Fr. is considered a
valid taxon from studies of the type collection. Brief notes on other termite
mound inhabiting species are given.
Late palaeocene Cupressaceae macrofossils at Lake Bungarby, New South Wales
Authors: Whang Sung Soo , Hill Robert S.
Published: January 2006

Four species of conifer macrofossils are described from the Late Palaeocene
Lake Bungarby sediments in southern New South Wales. Two are assigned to the
Cupressaceae and are considered to represent new species of
Libocedrus, L. acutifolius and
L. obtusifolius, although it is recognised that both
share some characters with Austrocedrus. Two other
fossils are considered to have less certain affinities with the Cupressaceae,
although both have cuticular micromorphology that contains synapomorphies for
that family. Both are assigned to new genera.
Bungarbia linifolius has entire, petiolate, univeined
leaves that resemble Metasequoia leaves, although the
cuticular morphology is very distinct from that genus. Unfortunately, the
phyllotaxis of Bungarbia is unknown.
Monarophyllum has leaves in apparently opposite pairs,
with the leaves bilaterally flattened. This combination of phyllotaxis and
leaf flattening is currently unknown in the Cupressaceae.
New species and a new combination in Australian Celmisia (Asteraceae - Astereae)
Authors: Gray M. , Given D. R.
Published: January 2006

Three new species of Celmisia
(C. tomentella, C. pugioniformis
and C. costiniana) from mainland south-eastern Australia
are described, and a new combination (C. latifolia) is
made for an endemic species from Victoria.
Macrofossils of Callicoma and Codia (Cunoniaceae) from Australian Cainozoic sediments
Authors: Barnes Richard W. , Hill Robert S.
Published: January 2006

Leaves, leaf fragments and two infructescences from five widespread Australian Cainozoic fossil localities, Little Rapid River, Lemonthyme Creek, Cethana(Early Oligocene), Berwick Quarry (Oligocene–Early Miocene) and StuartCreek (Miocene–Pliocene) are assigned to, or validated as, the extantspecies Callicoma serratifolia Andrews. The extantspecies or, more likely, a very close relative, evolved prior to the EarlyOligocene and has since remained relatively unchanged. It has becomerestricted to the forests of eastern mainland Australia, probably in responseto climatic change during the Cainozoic. The first macrofossil ofCodia, C. australiensis R.W.Barnes & R.S.Hill sp. nov., is described from West Dale (MiddleEocene–Oligocene), Western Australia, and has affinities with thejuvenile foliage of at least one extant Codia species.Several structures of Callicoma and someCodia species (stomatal cutin frill/ledge and pairedhair bases) may be synapomorphies for these genera.Callicoma serratifolia and Codiamay share a unique common ancestor, or alternatively,C. serratifolia may represent a paedomorphic form ofCodia.
Regulation of motor performance and striatal function by synaptic scaffolding proteins of the Homer1 family
Authors: Tappe Anke , Kuner Rohini
Published: January 2006

Intracellular calcium mobilization and signaling mechanisms triggered by activation of synaptic glutamate receptors in the striatum are important modulators of neurotransmission in striatal circuits. However, the expression and functions of scaffolding proteins anchoring glutamate receptors at striatal synapses have not been addressed so far. The long-form Homer1 proteins, Homer1b/c, assemble group I metabotropic glutamate receptors (mGluR1/5) in large macromolecular complexes with sources of calcium influx and release at synapses as well as with components of the NMDA receptor complex at the neuronal cell membrane. Homer1a, the short, activity-dependent splice variant of Homer1b/c, lacks the ability of linking mGluR1/5 to synaptic proteins and functions as an endogenous negative modulator of the mGluR1/5 inositol 1,4,5-trisphosphate receptor signaling complex. We have generated transgenic mice, which overexpress Homer1a in striatal medium spiny neurons either homogenously throughout the extrastriosomal matrix (Homer1a-matrix line) or predominantly in striosomal patches (Homer1a-striosome line). Homer1a-expressing mice demonstrated normal development of striatal structure and afferent–efferent connectivity. However, motor performance in behavioral tasks and striatal responses to the psychomotor stimulant amphetamine were significantly altered in the Homer1a-striosome line. Thus, glutamate receptor scaffolding proteins of the Homer1 family critically regulate the functions of striatal medium spiny neurons in complex motor tasks and its modulation by psychomotor stimulant drugs.
Molecular analysis of the bacterial microbiota in the human stomach
Authors: Bik Elisabeth M. , Eckburg Paul B. , Gill Steven R. , Nelson Karen E. , Purdom Elizabeth A. , Francois Fritz , Perez-Perez Guillermo , Blaser Martin J. , Relman David A.
Published: January 2006

The microbiota of the human stomach and the influence of
Helicobacter pylori
colonization on its composition remain largely unknown. We characterized bacterial diversity within the human gastric mucosa by using a small subunit 16S rDNA clone library approach and analyzed 1,833 sequences generated by broad-range bacterial PCR from 23 gastric endoscopic biopsy samples. A diverse community of 128 phylotypes was identified, featuring diversity at this site greater than previously described. The majority of sequences were assigned to the
Proteobacteria
,
Firmicutes
,
Actinobacteria
,
Bacteroidetes
, and
Fusobacteria
phyla. Ten percent of the phylotypes were previously uncharacterized, including a
Deinococcus
-related organism, relatives of which have been found in extreme environments but not reported before in humans. The gastric clone libraries from 19 subjects contained
H. pylori
rDNA; however, only 12 of these subjects tested positive for
H. pylori
by conventional laboratory methods. Statistical analysis revealed a large degree of intersubject variability of the gastric ecosystem. The presence of
H. pylori
did not affect the composition of the gastric community. This gastric bacterial rDNA data set was significantly different from sequence collections of the human mouth and esophagus described in other studies, indicating that the human stomach may be home to a distinct microbial eco-system. The gastric microbiota may play important, as-yet-undiscovered roles in human health and disease.
Immunity and behavior: Antibodies alter emotion
Authors: Huerta Patricio T. , Kowal Czeslawa , DeGiorgio Lorraine A. , Volpe Bruce T. , Diamond Betty
Published: January 2006

Systemic lupus erythematosus is an autoimmune disease in which most patients express Abs that bind double-stranded DNA. Recent work has shown that a subset of lupus Abs can crossreact with the NR2A and NR2B subunits of the NMDA receptor. This receptor is expressed in neurons throughout the brain but is at highest density within cells of the hippocampus, amygdala, and hypothalamus. The neurons in the CNS are normally protected from brain-reactive Abs by the blood–brain barrier (BBB); however, a breach in the barrier's integrity exposes neurons to potentially pathogenic Abs. Previously, we have shown that mice that are immunized with a peptide mimetope of DNA produce lupus-like Abs that crossreact with DNA and the NMDA receptor. Moreover, after abrogation of the BBB by treatment with lipopolysaccharide, the immunized mice display hippocampal neuron damage with ensuing memory impairment. Given that rises in epinephrine can increase cerebral blood flow and can cause leaks in the BBB, we decided to investigate whether epinephrine could act as a permissive agent for Ab-mediated neurotoxicity. Here, we show that peptide-immunized mice, given epinephrine to open the BBB, lose neurons in the lateral amygdala and develop a behavioral disorder characterized by a deficient response to fear-conditioning paradigms. Thus, the agent used to open the BBB determines which brain region is made vulnerable to neurotoxic Abs, and Abs that penetrate brain tissue can cause changes not only in cognitive competence, but also in emotional behavior.