B-chromosome behaviour in Phaulacridium vittatum

Nine individuals of Phaulacridium vittatum in a single population sample of 1250 males collected at Crookwell, N. S.W. contained a single supernumerary chromosome. One further individual had two B-chromosomes. The supernumerary in question was larger than any of the standard set and was distinguishable from them at all stages of mitosis and meiosis. Like the X-univalent the B-chromosome was heteropycnotic at the onset of meiosis but differed from it in size, structure and behaviour. During first prophase single supernumeraries were frequently associated with the X in a non-homologous fashion as a consequence of their precocity. All such associations lapsed before first metaphase and the X and the B moved at random with respect to one another at first anaphase. In the one individual with two supernumeraries the two B-chromosomes showed regular pairing and segregated in a conventional manner. In all these respects the Crookwell supernumerary differed markedly from a morphologically identical B-chromosome present in a population of the same species from Hobart, Tasmania studied by Jackson and Cheung in 1967. Whether these differences in the behaviour of the B-chromosome in the two populations determines the higher frequency of the supernumerary in Hobart (11.3%) as compared with Crookwell (0.8%) remains to be resolved.     

LIMaS: the JAVA-based application and database for microarray experiment tracking

Microarrays allow monitoring of gene expression for tens of thousands of genes in parallel and are being used routinely to generate huge amounts of valuable data. Handling and analysis of such data are becoming major bottlenecks in the utilization of the technology. To enable the researcher to interpret the results postanalysis, we have developed a laboratory information management system for microarrays (LIMaS) with an n-tier Java front-end and relational database to record and manage large-scale expression data preanalysis. This system enables the laboratory to replace the paper trail with an efficient and fully customizable interface giving it the ability to adapt to any working practice, e.g., handling many resources used to form many products (chaining of resources). The ability to define sets of activities, resources, and workflows makes LIMaS MIAME-supportive.LIMaS is available for download at (http://www.mgu.har.mrc.ac.uk/microarray.)     

Some effects of thyroidectomy on growth, heat production and the thermoregulatory ability of the immature fowl (Gallus domesticus)

1. 1.|The effect of thyroidectomy at 12 days of age on weight gain, and on heat production and thermoregulatory ability of 4- to 5-week-old chickens at temperatures within and below the thermo-neutral zone was investigated.

2. 2.|Despit the absence of thyroid tissue, as demonstrated with radioiodine, a small amount of thyroxine was found in the plasma of some thyroidectomized (TX) birds.

3. 3.|Thyroidectomy depressed weight gain; pair-fed controls grew significantly faster than TX birds.

4. 4.|Resting heat production of TX birds at thermoneutrality (30°C) was depressed by 18% (P < 0.001) and body temperature by 0.4°C (P < 0.001).

5. 5.|At 12°C heat production of TX birds was similar to that of controls but the body temperature of TX birds was 0.7°C lower (P < 0.001).

6. 6.|Thyroidectomized birds were unable to regulate body temperature at 5°C even if thyroxine was provided on the day before and at the time of cold-exposure. This inability to thermoregulate was probably due to inadequate insulation and poor nutritional status.

Monitoring the stability of crosslinked protein crystals biotemplates: a feasibility study

Protein crystals, routinely prepared for the elucidation of protein 3D structures by X-ray crystallography, present an ordered and highly accurate 3D array of protein molecules. Inherent to the 3D arrangement of the protein molecules in the crystal is a complementary 3D array of voids made of interconnected cavities and exhibiting highly ordered porosity. The permeability of the porosity of chemically crosslinked enzyme protein crystals to low molecular weight solutes, was used for enzyme mediated organic synthesis and size exclusion chromatography. This permeability might be extended to explore new potential applications for protein crystals, for example, their use as bio-templates for the fabrication of novel, nano-structured composite materials. The quality of composites obtained from "filling" of the ordered voids in protein crystals and their potential applications will be strongly dependent upon an accurate preservation of the order in the original protein crystal 3D array during the "filling" process. Here we propose and demonstrate the feasibility of monitoring the changes in 3D order of the protein array by a step-by-step molecular level monitoring of a model system for hydrogel bio-templating by glutaraldehyde crosslinked lysozyme crystals. This monitoring is based on step-by-step comparative analysis of data obtained from (i) X-ray crystallography: resolution, unit cell dimensions and B-factor values and (ii) fluorescence decay kinetics of ultra-fast laser activated dye, impregnated within these crystals. Our results demonstrated feasibility of the proposed monitoring approach and confirmed that the stabilized protein crystal template retained its 3D structure throughout the process.     

Preliminary crystallographic data for plastocyanins from an alga (Enteromorpha prolifera) and from cucumber (Cucumis sativus)

The plastocyanins from a green alga (Enteromorpha prolifera) and cucumber (Cucumis sativus) have been crystallized. Crystal data are as follows: E. prolifera plastocyanin, space group I4, a = b = 53.9 A, c = 59.4 A, Z = 8; C. sativus plastocyanin, space group P4(1) (or P4(3) ), a = b = 66.7 A, c = 46.0 A, Z = 8. Accordingly, the asymmetric units of the crystals contain one and two molecules, respectively.     

Differential effect of zinc on teratogen-induced inhibition of pinocytosis by cultured rat yolk sac

Pinocytosis as measured by the uptake of 125I labelled PVP by the isolated cultured day 12 rat yolk sac was observed to be linear over a 4 h incubation period and to proceed at a rate of approximately 2.5 microliters/mg protein/h. Cadmium, anti-visceral yolk sac antibody (AVYS) and trypan blue all inhibited pinocytosis in a concentration-dependent fashion when added to the culture medium, although at low concentrations trypan blue was slightly stimulatory. The effect of zinc on the inhibition of pinocytosis by these three teratogens was studied. It was observed that zinc ameliorated the inhibitory effects of cadmium and AVYS, but had no effect on inhibition by trypan blue. These results indicate that the previously demonstrated protective action of zinc against cadmium-induced yolk sac dysfunction is not specific to that agent but extends to inhibition of pinocytosis by AVYS, and further suggest that, because of its refractoriness to zinc, trypan blue-induced inhibition of pinocytosis by yolk sac occurs by a mechanism different from that effected by cadmium and AVYS.     

Rapid warming is associated with population decline among terrestrial birds and mammals globally

Animal populations have undergone substantial declines in recent decades. These declines have occurred alongside rapid, human‐driven environmental change, including climate warming. An association between population declines and environmental change is well established, yet there has been relatively little analysis of the importance of the rates of climate warming and its interaction with conversion to anthropogenic land use in causing population declines. Here we present a global assessment of the impact of rapid climate warming and anthropogenic land use conversion on 987 populations of 481 species of terrestrial birds and mammals since 1950. We collated spatially referenced population trends of at least 5 years’ duration from the Living Planet database and used mixed effects models to assess the association of these trends with observed rates of climate warming, rates of conversion to anthropogenic land use, body mass, and protected area coverage. We found that declines in population abundance for both birds and mammals are greater in areas where mean temperature has increased more rapidly, and that this effect is more pronounced for birds. However, we do not find a strong effect of conversion to anthropogenic land use, body mass, or protected area coverage. Our results identify a link between rapid warming and population declines, thus supporting the notion that rapid climate warming is a global threat to biodiversity.     

Charge properties of mitochondrial matrix proteins.

Proteins of the rat liver mitochondrial matrix have been separated into anionic (acidic), cationic(basic), and neutral groups by electrophoresis. These groups represent 69, 8, and 23% of the total matrix protein, respectively, compared to 69, 21, and 10% for the cytosol protein. The acidic nature of the mitochondrial matrix proteins has been confirmed by cellulose ion-exhange chromatography, isoelectric focusing in sucrose gradients, and amino acid analysis. The anionic, cationic, and neutral matrix proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis into 18, 6, and 5 bands, respectively, compared to 22 bands for the total fraction. The significance of the charge properties of these proteins in terms of mitochondrial biogenesis is discussed.