Taphonomy and diagenesis in diatom assemblages; a Late Pleistocene palaeoecological study from Lake Magadi,Kenya

During these investigations the following species of Anostraca have been found: Chirocephalus diaphanus Prevost 1803, Chirocephalus brevipalpis (Orghidan, 1953), Streptocephalus torvicornis Waga 1892, Branchipus serbicus Marinek & Petrov 1988, Branchipus stagnalis L. (1758) and Branchipus sp. Thus, the total number of species discovered in Yugoslavia is 13.The shape of the frontal shield and the degree of flexure of the distal articles of antennae II in males are of no relevance to taxonomy in the genus Branchipus Schaeffer 1776. However, the apophyses on antennae II in males, shape of antennae II and of the ovisac in females, structure of eggs, and of appendages appear species-specific. We conclude that the differentiation of B. stagnalis into two forms (forma typica and forma visnyai) as well as the separation of B. visnyai Kertész 1956 as a distinct species are unfounded.     

The common acute lymphoblastic leukemia antigen gene maps to chromosomal region 3 (q21-q27)

Complementary DNA and genomic clones corresponding to the gene for the common acute lymphoblastic leukemia antigen (CALLA) were used to investigate the genetic structure and location of the CALLA locus. The gene, which encodes a 100-kDa type II transmembrane glycoprotein, appears to be a single copy locus of greater than 45 kb which is not rearranged in malignancies expressing cell surface CALLA. Cell hybrid analysis indicates that the CALLA-related DNA sequences are found on human chromosome 3. In situ hybridization studies reveal the regional location of the CALLA locus to be 3q21-27.     

Yeast aspartate aminotransferase: preparation of the apoenzyme and its interaction with coenzyme analogues

Affinity chromatography of yeast aspartate aminotransferase [l-aspartate: 2-oxoglutarate aminotransferase, EC 2.6.1.1] on N′(ω-aminohexyl) pyridoxamine-5-phosphate Sepharose 4B is reported. The specific activity of the enzyme obtained, fully activated with pyridoxal-5-phosphate, was higher than that of previous preparations but the yield of purified enzyme was poor. Purification using DEAE-cellulose gave a higher yield of enzyme with lower specific activity. This preparation contained an appreciable amount of the holoenzyme. Use of sodium borohydride permitted the preparation of apoenzyme containing only 1.4% of the holo-form. Four coenzyme analogues were synthesized. These were the N′-acetyl-, the N′-methyl- and the N′-benzyloxycarbonylglycyl-pyridoxamine-5-phosphate and the O-acetylpyridoxal-5-phosphate. The three N′-substituted pyridoxamine-5-phosphate derivatives were all effective inhibitors of the enzyme, while the O-acetylpyridoxal-5-phosphate bound to the apoenzyme and gave an active enzyme.     

THE FOODS OF GREAT AND SOOTY SHEARWATERS PUFFINUS GRAVIS AND P. GRISEUS IN EASTERN CANADIAN WATERS

The foods of Great and Sooty Shearwaters Puffinus gravis and P. griseus are described from birds collected off eastern Canada. There was a broad overlap in diet, but Great Shearwaters tended to take more squid and tough-bodied fish such as mackerel Scomber scombrus while Sooties took more euphausiids Meganyctiphanes norvegica and soft-bodied fish such as Herring Clupea harengus . These differences are apparently related to differences in bill structure and in the degree of adaptation to underwater swimming.
The birds appeared to feed opportunistically on whatever prey was locally available in the size-range between euphausiids and small fish and squid: Meganyctiphanes off southwest Nova Scotia, spawning and post-spawning capelin Mallotus villosus off eastern Newfoundland, and migrating squid Illex illecebrosus on the Grand Bank. Possible factors influencing prey selection are discussed. It is suggested that the timing and routes of the birds' migrations in the North Atlantic are related to the exploitation of such local concentrations.
Despite the overlap in diets, differences in the distributions of the two species rule out the possibility of significant competition for common food resources.     

Acute appendicitis in nine British towns.

The incidence of acute appendicitis was compared among residents in nine towns in England and Wales, the towns having been chosen so that three were in the north, three in the central latitude band, and three in the south. Each group of three towns comprised one with "better,'' one with "intermediate,'' and one with "worse'' socioeconomic conditions. The data were derived from hospital records for the years 1974-7. Hospital discharge rates for acute appendicitis were higher in the three northern towns in both sexes and all age groups. There was no consistent variation with the socioeconomic state of the towns. The distribution of appendicitis in the nine towns differed from that of other "diseases of Western civilisation'' and so weighs against the hypothesis of similar dietary influences in the aetiology of acute appendicitis and these other diseases. These findings are being followed up by dietary surveys in the towns.     

Pathway of lysine degradation in Fusobacterium nucleatum.

Lysine was fermented by Fusobacterium nucleatum ATCC 25586 with the formation of about 1 mol each of acetate and butyrate. By the use of [1-14C]lysine or [6-14C]lysine, acetate and butyrate were shown to be derived from both ends of lysine, with acetate being formed preferentially from carbon atoms 1 and 2 and butyrate being formed preferentially from carbon atoms 3 to 6. This indicates that the lysine carbon chain is cleaved between both carbon atoms 2 and 3 and carbon atoms 4 and 5, with the former predominating [1-14C]acetate was also extensively incorporated into butyrate, preferentially into carbon atoms 3 and 4. Cell-free extracts of F. nucleatum were shown to catalyze the reactions of the 3-keto,5-aminohexanoate pathway of lysine degradation, previously described in lysine-fermenting clostridia. The 3-keto,5-aminohexanoate cleavage enzyme was partially purified and shown to have properties much like those of the clostridial enzyme. We conclude that both the pathway and the enzymes of lysine degradation are similar in F. nucleatum and lysine-fermenting clostridia.     

Use of bio-lac fusion strains to study regulation of biotin biosynthesis in Escherichia coli.

The technique developed by Casadaban (M. J. Casadaban, J. Mol. Biol. 104: 541-555, 1976) has been employed to construct Escherichia coli K-12 derivatives in which the genes determining lactose utilization are fused to the regulatory region of the biotin operon. Fusions of the lac genes to either arm of this divergently transcribed operon have been isolated. When the operon is derepressed, expression of the lac genes is sufficient to permit growth on lactose minimal medium. Repressing conditions prevent growth on lactose. This property of bio-lac fusion strains, as well as the ease of determining the level of operon expression by assaying beta-galactosidase, was used for the isolation and characterization of mutants defective in repression. Preliminary analyses of several newly isolated regulatory mutants are presented. For the several birA mutants examined, there appeared to be no direct correlation between effects on minimum biotin requirement and alterations in repressibility, suggesting a possible dual function for the gene. Parallel attempts to obtain fusions of lac to bioH were unsuccessful, indicating lack of direct biotin control at the bioH locus.     

Herpesvirus-like infection in a painted turtle (Chrysemys picta)

A painted turtle (Chrysemys picta) which died in captivity had marked necrosis in the liver and lungs with numerous intranuclear inclusion bodies in hepatocytes and respiratory epithelial cells. Electron microscopy revealed herpesvirus-like particles in cells in affected tissues.     

A comparative study of interspecies mating of Phratora vulgatissima and P. vitellinae using behavioural tests and molecular markers

The leaf beetle genus Phratora L. (Coleoptera: Chrysomelidae) has been used to study the ecology of host plant chemicals in herbivore preference, and the evolution of host use in chemical defence. Phratora vulgatissima and P. vitellinae are sympatric species distributed widely across Europe. Their trophic niches are largely separate due to strong differences in their host feeding preference, but they have occasionally been recorded together, feeding on Salix burjatica‘Germany’ and, only in early spring, on Populus trichocarpa (Torr & A. Gray) ‘Trichobel’. Using behavioural tests and recently developed species‐specific microsatellite markers, the intra‐ and interspecific mating of both beetle species were investigated. The microsatellite markers provided evidence that interspecific mating occurred under field conditions. Interspecific mating also took place under laboratory conditions, but less frequently than mating within species. Females of both species laid fewer eggs, and fewer eggs per clutch, when isolated with an interspecific male than with a conspecific male. Female P. vulgatissima were polyandrous, as microsatellite markers showed that their larvae were the progeny of both P. vulgatissima males that had been isolated with a single female. While only 0.55% of eggs laid in interspecific pair combinations hatched, microsatellite markers provided evidence of hybridisation between beetle species; however, these larvae died within a week when reared in a Petri dish containing ‘Germany’ and P. trichocarpa leaves. It can therefore be inferred that reproductive isolation is complete. The results are discussed in relation to species integrity and the implications for diverse mixtures of short‐rotation coppice willow plantations.