Laboratory experiments on planetary and stellar convection performed on spacelab 3

Experiments on thermal convection in a rotating, differentially heated hemispherical shell with a radial buoyancy force were conducted in an orbiting microgravity laboratory. A variety of convective structures, or planforms, were observed, depending on the magnitude of the rotation and the nature of the imposed heating distribution. The results are compared with numerical simulations that can be conducted at the more modest heating rates, and suggest possible regimes of motion in rotating planets and stars.     

Induction of apoptosis in sea bream fibroblasts by Vibrio harveyi haemolysin and evidence for an anti‐apoptotic role of heat shock protein 70

In this study, we exposed black sea bream, Mylio macrocephalus (Basilewsky), fibroblast (BSF) and silver sea bream, Sparus sarba Forsskål, fibroblast (SSF) cell lines to a recombinant Vibrio harveyi haemolysin (VHH) and investigated mechanisms involved in apoptosis. A decrease in mitochondrial membrane potential, followed by an increase in caspase 3 activity, occurred within 2–8 h of VHH exposure, in both cell lines; however, VHH did not alter cellular levels of reactive oxygen species. As heat shock protein 70 (HSP70) is known to prevent the onset of apoptosis in certain mammalian cells, we aimed to test whether such a protective effect is operative in VHH‐exposed fibroblasts. The amounts of HSP70 were elevated in SSF and BSF via an acute heat shock or an acute heat shock followed by a 6 h recovery. It was found that the VHH‐mediated reduction in mitochondrial membrane potential was suppressed in cells that had a 6 h post‐heat shock recovery, and the protective effect of heat shock‐induced HSP70 was attenuated following treatment of cells with the HSP70 inhibitor, quercetin. This study demonstrates how haemolysin causes cell death via induction of apoptosis and provides evidence as to the role of HSP70 as an anti‐apoptotic factor.     

Development of a black sea bream fibroblast cell line and its potential use as an <Emphasis Type="Italic">in vitro</Emphasis> model for stress protein studies

A fibroblast cell line (BSF) derived from a caudal fin explant of black sea bream (Mylio macrocephalus) was developed. The optimum fetal bovine serum (FBS) concentration for fibroblast cell line growth was found to be 15–20% v/v FBS and the optimum temperature range for growth was found to be 26–30 °C. The fibroblast cells displayed a diverse distribution in chromosome number with two modal chromosome numbers of 48 and 54. Upon acute heat shock (+8 °C) the cells displayed a 4.1 fold increase in hsp70 and this elevation was not prolonged as hsp70 returned to near basal levels following a 6 h recovery period. The effect of the hsp70 inducer L-azetidine- 2-carboxylic acid was tested and it was found that at a concentration of 10 mM this inducer caused a 2.3 fold increase in hsp70 levels. The sensitivity of the fibroblast cell line to heavy metal exposure was tested by treatment with Cu2+ and it was found that hsp70 was significantly elevated in the presence of micromolar concentrations of Cu2+. The data from this study demonstrates that the established black sea bream fibroblast cell line could serve as a useful in vitro model for stress protein studies.     

Comparison of characteristics of actomyosin from white, pink, and red muscle fiber types in cultured carp

ABSTRACT: The present study compared and examined the characteristics of actomyosin among white (W), pink (P), and red (R) muscle fiber types in carp (cultured). Both the superprecipitation reaction and the Mg²⁺-ATPase activity of actomyosin became higher with increased Ca²⁺ concentration (pCa 7.0–pCa 5.0) and with decreased adenosine triphosphate (ATP) concentration (3.0–0.5 mM) in all three muscle fiber types. A comparison of the three fiber types shows that the superprecipitation reaction of actomysoin was lower in the order of W < P < R and, in contrast, was higher for Mg²⁺-ATPase activity in the order of W > P > R. A significantly positive correlation between both values was found for each of the three muscle fiber types, but these correlations were clearly different among the three muscle fiber types, and the superprecipitation reaction of actomyosin was lower in the order of W < P < R when Mg²⁺-ATPase activity was at the same level. In conclusion, the characteristics of actomyosin were remarkably different among white, pink, and red muscle fiber types.     

The effect of the TLR9 ligand CpG-oligodeoxynucleotide on the protective immune response to alcelaphine herpesvirus-1-mediated malignant catarrhal fever in cattle

We wished to determine the effect of of CpG ODN adjuvant on the magnitude and duration of protective immunity against alcelaphine herpesvirus-1 (AlHV-1) malignant catarrhal fever (MCF), a fatal lymphoproliferative disease of cattle. Immunity was associated with a mucosal barrier of virus-neutralising antibody. The results showed that CpG ODN included either with emulsigen adjuvant and attenuated AlHV-1 (atAlHV-1) or alone with atAlHV-1 did not affect the overall protection from clinical disease or duration of immunity achieved using emulsigen and atAlHV-1. This is in contrast to other similar studies in cattle with BoHV-1 or cattle and pigs with various other immunogens. In addition to this, several other novel observations were made, not reported previously. Firstly, we were able to statistically verify that vaccine protection against MCF was associated with virus-neutralising antibodies (nAbs) in nasal secretions but was not associated with antibodies in blood plasma, nor with total virus-specific antibody (tAb) titres in either nasal secretions or blood plasma. Furthermore, CpG ODN alone as adjuvant did not support the generation of virus-neutralising antibodies. Secondly, there was a significant boost in tAb in animals with MCF comparing titres before and after challenge. This was not seen with protected animals. Finally, there was a strong IFN-γ response in animals with emulsigen and atAlHV-1 immunisation, as measured by IFN-γ secreting PBMC in culture (and a lack of IL-4) that was not affected by the inclusion of CpG ODN. This suggests that nAbs at the oro-nasal-pharyngeal region are important in protection against AlHV-1 MCF.     

Effects of Exogenous Insulin on Luteolysis and Reproductive Cyclicity in the Mare

Insulin is a pancreatic hormone that classically regulates carbohydrate and fat metabolism, but also appears to play a role in various reproductive processes. A preliminary study suggested insulin production by day 10 to 18 equine conceptuses. The aim of the present study was to examine the hypothesis that insulin is the conceptus signal responsible for maternal recognition of pregnancy (MRP) in the mare, or otherwise influences reproductive cyclicity during the MRP period. Six Warmblood mares were treated daily during days 7 to 17 after ovulation of two successive oestrous cycles with either (short and intermediate acting) insulin or control saline. Mares were assigned randomly to treatment, and crossed over during the subsequent cycle. Time of ovulation and corpus luteum surface area were determined by serial transrectal ultrasonographic examination of the mares' ovaries, and daily jugular vein blood samples were analysed for progesterone and luteinizing hormone (LH) concentrations. On day 14 of dioestrus, the luteolytic drive was examined by measuring systemic 15-ketodihydroprostaglandin F_{2 α} (PG-metabolite) release in response to oxytocin challenge. In addition, yolk sac fluid recovered from 32 day 10 to 14 equine conceptuses was analysed for insulin concentrations. Insulin administration did not affect luteal size, dioestrus length, the interovulatory interval, or circulating LH concentrations. Insulin administration also failed to suppress oxytocin-induced PGF_{2 α} release, and tended to depress systemic progesterone concentrations. Finally, insulin could not be detected in the yolk sac fluid of day 10 to 14 equine conceptuses by radio-immunoassay. It is concluded that insulin administered daily during days 7 to 17 of dioestrus has little or no effect on reproductive cyclicity in the mare, and is unlikely to be the MRP signal.     

Correlation of Blood Flow of the Preovulatory Follicle to its Diameter and Endocrine Profile in Dairy Buffalo

Blood flow of the preovulatory follicle (POF) wall can be used as a predictor of the quality of POF. Our aim was to determine the correlation of blood flow of POF with the POF diameter, and intra‐follicular and plasma concentrations of Insulin‐like Growth Factor‐I (IGF‐1) and oestradiol in dairy buffalo. Nine Murrah buffalo subjected to an ovulation synchronization protocol (Ovsynch) were assessed on day 10 of the protocol for diameter and blood flow of POF, followed by the aspiration of follicle fluid. Prior to follicular aspiration, blood samples were obtained from jugular vein for estimation of IGF‐1 and oestradiol. The vascularity of POF was determined (Range: 250–967 pixel²) along with intra‐follicular and plasma concentration of IGF‐1 (Range: 9.3–31.8 ng/ml and 14.7–29.7 ng/ml respectively) and oestradiol (Range: 124.2–447.9 ng/ml and 0.25–1.05 ng/ml respectively). Diameter of the POF was weakly correlated (r = 0.21, p < 0.01) with blood flow to it. As compared to POF diameter, the blood flow of POF had greater positive correlation with intra‐follicular and plasma concentrations of hormones (IGF‐1 and oestradiol). A strong positive correlation was recorded between intra‐follicular IGF‐1 and oestradiol. Also, plasma concentrations of oestradiol and progesterone were negatively correlated In brief, assessment of the blood flow of the POF is a non‐invasive and reliable indicator of its functional competence as compared to the POF diameter.     

The effect of oestrus and the presence of pouch young on aerobic bacteria isolated from the pouch of the tammar wallaby, Macropus eugenii

Qualitative changes in the culturable, aerobic bacterial flora isolated from the tammar pouch have been documented over the period leading up to oestrus, at the time of anticipated birth and in absence and presence of pouch young of varying ages. In a group of 12 animals studied thirty species of aerobic bacteria were isolated. Twenty five species were found in pouches with no pouch young, 9 in pouches with young less than 3 weeks of age and 9 in pouches containing older animals. Gram positive organisms including Corynebacterium spp., Micrococcus spp. and Staphylococcus spp. were the most frequent isolates, regardless of reproductive status. Whilst Gram-negative rods Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter aerogenes, and Escherichia coli were found in pouches with and without pouch young, but not in pouches close to oestrus, at the time of birth or in the presence of very young animals (<6 days). While pouches without pouch young displayed the greatest diversity of bacterial species, there were still significant numbers of bacterial species in those containing pouch young. Results suggest that the microbial population of the tammar pouch does not seriously compromise the well-being of the young animal during crucial stages of immunological development. The data are consistent with observations on the microflora of the quokka pouch but not with data from the koala.

Résumé

Les changements dans la diversité et la composition des populations de bactéries aérobies, isolées de la poche du tammar wallaby et cultivées, ont été suivis au cours de la période précédant l'oestrus, au moment de la naissance du jeune et après la naissance, dans des poches avec ou sans jeune. Trente différentes espèces de bactéries ont été isolées de la poche de 12 animaux: 25 espèces isolées de poches vides, neuf espèces de poches contenant un jeune de moins de trois semaines et neuf espèces de poches contenant un jeune de plus de trois semaines. Les bactéries Gram-positives Corynebacterium spp., Micrococcus spp. et Staphylococcus spp. ont été les plus fréquemment rencontrées, et ce quelque soit la période du cycle reproductif. Les espèces Gram-negatives Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter aerogenes, et Escherichia coli ont été constamment isolées de poches vides, lorsque le tammar n'était ni en période proche de l'oestrus, ni proche de la naissance et ont été constamment isolées de poches contenant un jeune si celui-ci était agé de plus de six jours. Les plus grandes diversités spécifiques ont été relevées dans les poches vides, bien que les poches contenant un jeune ont toujours présenté un nombre significant d'espèces bactériennes. Les résultats suggèrent que les différentes populations bactériennes présentes dans la poche du tammar ne semblent affecter ni le bon dévelopement, ni la santé du jeune dans la poche, spécialement lors du dévelopement de ses capacités immunologiques. Ces résultats sont en accord avec ceux ceux obtenus pour le quokka, mais differents de ceux obtenus pour le koala.     

Defects in semiconductors: some fatal, some vital

REVIEW The role of defects as essential entities in semiconductor materials is reviewed. Early experiments with semiconductors were hampered by the extreme sensitivity of the electronic properties to minute concentrations of impurities. Semiconductors were viewed as a family of solids with irreproducible properties. Scientific efforts overcame this idiosyncrasy and turned the art of impurity doping into today's exceedingly useful and reproducible technology that is used to control precisely electrical conductivity, composition, and minority-carrier lifetimes over wide ranges. Native defects such as vacancies and self-interstitials control basic processes, foremost self- and dopant diffusion. The structural properties of dislocations and higher dimensional defects have been studied with atomic resolution, but a thorough theoretical understanding of their electronic properties is incomplete. Reactions between defects within the host lattices are increasingly better understood and are used for gettering and electrical passivation of unwanted impurities. Metastable defects such as DX centers and the EL2-related arsenic antisite are briefly discussed. The recent development of isotopically controlled semiconductors has created new research opportunities in this field.