A human cDNA encoding the small subunit of RNA polymerase II transcription factor SIII

A full-length cDNA encoding a human homolog of the 15-kDa subunit (p15) of RNA polymerase II elongation factor SIII was isolated and sequenced. Comparison of the open reading frames of the human p15 cDNA and the previously characterized rat p15 cDNA [Garrett et al., Proc. Natl. Acad. Sci. USA 91 (1994) 5237-5241] indicates that they encode identical proteins and are 93% conserved in nucleotide sequence.     

Determination of ammonium and L-Glutamine in hybridoma cell cultures by sequential flow injection analysis

A flow injection anlytical system based on a gas diffusion membrane module for ammonia and an ammonium flow-through potentiometric detector has been set up for measurement of L-glutamine and ammonium ions in hybridoma cell cultures. The main feature of the system is that the same basic analytical concept and equipment is used in both measurements, the only difference being for the determination of L-glutamine, in which the sample flows through an immobilized glutaminase cartridge. The conditions to enable the performance of both analysis consecutively, avoiding potential interferences by unwanted deamination of other compounds in the samples, have been determined. Finally, the proposed system has been compared with reference analytical methods for batch hybridoma cell culture experiments.     

Genotypic variation in biological nitrogen fixation by common bean

Field experiments were performed in Austria, Brazil, Chile, Colombia, Guatemala, Mexico and Peru as part of an FAO/IAEA Co-ordinated Research Programme to investigate the nitrogen fixing potential of cultivars and breeding lines of common bean (Phaseolus vulgaris L.). Each experiment included approximately 20 bean genotypes which were compared using the ¹⁵N isotope dilution method. Great differences in nitrogen fixation were observed between and within experiments, with average values of 35% N derived from atmosphere (% Ndfa) and highest values of 70% Ndfa being observed. These values which were larger than had been reported previously for common bean, were observed only when environmental factors were favorable. Therefore, common bean lines are available, which can support high biological nitrogen fixation. These can be used either directly as cultivars for production or in breeding programmes to enhance nitrogen fixation in other cultivars.     

Organic sulfur removal from coal by microorganisms from extreme environments

Abstract: Microbial samples were collected from sulfurous, near neutral pH, thermal waters of Yellowstone Park. Thermophilic mixed cultures were identified that removed 90% of pyritic and sulfate sulfur and 33% of the organic sulfur from North Dakota lignite. The 30–40% organic desulfurization barrier was studied for possible inhibitors to organic sulfur removal from coal.     

Gestation length in rhesus macaques (Macaca mulatta)

We describe some of the sources of variation in gestation length among rhesus macaques. the data were obtained from the timed-mating breeding program at the California Regional Primate Research Center (CRPRC). Information about approximately 700 pregnancies that resulted in spontaneous vaginal deliveries of liveborn young is presented. The average length of these pregnancies was 166.5 days. In this population, older females with higher parities had significantly longer pregnancies and significantly heavier infants than other females did. Other factors, including infant sex, month of conception, maternal reproductive history, and paternal identity, had no consistent effect upon gestation length.     

Copper deficient rat heart can compensate for doxorubicin-induced oxidant stress

The hypothesis that copper (Cu) alters drug metabolizing enzymes and functions as an antioxidant nutrient in doxorubicin cardiotoxicity was tested. Male Sprague-Dawley rats were fed Cu adequate (⁺Cu; 5 mg Cu/kg of diet), marginally Cu deficient (MCu; 1.2 mg Cu/kg of diet), or severely Cu deficient (⁻Cu; 0.5 mg Cu/kg of diet) diets for 6 wk. Doxorubicin (1, 2, or 4 mg/kg body wt) or saline were administered intraperitoneally 1 time/wk for 4 wk. Compared to control hearts, Cu, Zn superoxide dismutase activity was decreased by 9% in MCu rats and by 21–40% in⁻Cu rats. Glutathione peroxidase activity was elevated 5–15% in⁻Cu rats. Doxorubicin administration increased heart Cu, Zn superoxide dismutase activity in⁺Cu and⁻Cu rats 18 h after the last of 4 injections, but not 18 h after 1 injection. There was no synergism between doxorubicin and Cu deficiency on lipid peroxidation, plasma creatine phosphokinase, cardiac hypertrophy, electrocardiographic abnormalities, or morphological changes. Heart glutathione S-transferase activity was decreased by Cu deficiency, and like Cu, Zn superoxide dismutase activity, returned to normal in⁻Cu rats given doxorubicin. Thus, the Cu deficient rat heart may be able to compensate for doxorubicin-induced oxidant stress by increasing the activity of Cu,Zn superoxide dismutase and glutathione S-transferase.     

POLLEN MORPHOLOGY,TRICHOME TYPES,AND RELATIONSHIPS OF THE GRONOVIOIDEAE (LOASACEAE)

The pollen of all four genera of Gronovioideae—Cevallia, Fuertesia, Gronovia, and Petalonyx—was examined in light microscopy, and scanning and transmission electron microscopy. The pollen of Cevallia, of Fuertesia, and of Gronovia can be easily distinguished from each other and from all remaining Loasaceae. Only Petalonyx, with a striate tectum, shows a clear relationship to the Mentzelioideae and Loasoideae, the vast majority of which have striate-reticulate or striate tecta. The trichome data are mostly congruent with the pollen data: Cevallia, Fuertesia, and Gronovia each have a distinctive trichome not known to occur elsewhere in the family, while Petalonyx has only the common types. A cladistic analysis of Gronovioideae utilizing Mentzelia as the outgroup proposes that Cevallia, Gronovia, and Fuertesia are a sister group to Petalonyx within the subfamily. The relationships of the four genera to each other and of Gronovioideae to the Loasaceae are discussed.     

Fungal catabolic gene regulation: Molecular genetic analysis of theamdS gene ofAspergillus nidulans

Aspergillus nidulans is an excellent experimental organism for the study of gene regulation. Genetic and molecular analyses oftrans-acting andcis-acting mutations have revealed a complex pattern of regulation involving multiple independent controls. Expression of theamdS gene is regulated by thefacB andamdA genes which encode positively acting regulatory proteins mediating a major and a minor form of acetate induction respectively. The product of theamdR gene mediates omega amino acid induction ofamdS. The binding sites for each of these proteins have been localised throughamdS cis-acting mutations which specifically affect the interaction with the regulatory protein. The global controls of nitrogen metabolite repression and carbon catabolite repression regulate the expression of many catabolic genes, includingamdS. Nitrogen control is exerted through the positively actingareA gene product and carbon control is dependent on thecreA gene product. Each of the characterized regulatory genes encodes a DNA-binding protein which recognises particular sequences in theamdS promoter to activate or repress gene expression. In addition, there is evidence for other genetically uncharacterised proteins, including a CCAAT-binding complex, which interact with the 5 region of theamdS gene.     

Meiotic recombination in an Irish family with beta-thalassaemia

Using the technique of allele-specific priming of the polymerase chain reaction (PCR), the C-T substitution in codon 39 was identified as the cause of -thalassaemia in an Irish family. Analysis of the restriction fragment length polymorphisms (RFLPs) in the -globin gene cluster established linkage of the -thalassaemia mutation to a particular -haplotype but indicated that a recombinational event had occurred in the paternal chromosome in the younger of two affected children. Non-paternity was excluded by DNA fingerprinting analysis with hypervariable minisatellite probes. This is the fourth case of recombination in the -globin gene cluster to be reported. The event has occurred 5 of the polymorphic RsaI site at position-550 bp upstream of the -globin gene mRNA Cap site, within the 9.1-kb region that has been shown to be a hot spot for recombination in the -globin gene cluster.     

Experimental and field evidence of Antarctic foraminiferal tolerance to anoxia and hydrogen sulfide

The common occurrence of foraminifera in strata deposited under anoxic environmental conditions throughout the geologic record raises the question of whether foraminifera actually survive anoxic or reducing conditions. To test this, benthic foraminifera from McMurdo Sound, Antarctica were exposed to anoxic or reducing conditions for 30 days. These Antarctic forms are known to be exposed to anoxic events in their natural environment. An adenosine triphosphate (ATP) assay was used to determine foraminiferal survival, and their ultrastructure was examined using transmission electron microscopy (TEM) to evaluate any possible effect that might have resulted from exposure to anoxic or reducing conditions. The experimental treatments did not have any statistically significant effects upon the foraminifers with regards to survival or average ATP content per individual including the four most common living species. Some ultrastructural evidence for encystment (fibrillar membrane-bound bodies in the cytoplasm of many specimens) was observed. Field data include the observation thatGlobocassidulina cf.G. biora resides in sediments to depths of 7 cm, as evidenced by ultrastructural investigations. A specimen ofGlobocassidulina cf.G. biora collected from sediments containing anoxic pore waters showed numerous bacteria within the confines of the organic lining. The occurrence of cytoplasmic inclusions similar in appearance to car☐ysomes within these bacteria suggest possible affinities to the chemolithotrophicThiobacillus. Bacteria of this type were not observed in specimens collected from oxygenated pore waters. These field and laboratory findings suggest that certain foraminifera may be facultative anaerobes able to withstand reducing conditions.