Tyrosination-detyrosination of tubulin and microtubules during the development of chick erythrocytes

The protein composition of nuclear matrices containing different amount of DNA was examined. It was found that, in matrices containing 2% to 80% of total DNA, the quantity of DNA-bound proteins remains relatively constant varying from 10% to 15% of total nuclear proteins. Electrophoretic patterns do not differ substantially, but autoradiograms with in vitro ¹²⁵I labelled proteins show quantitative variations in the actin content. Application of radioimmunoassay (RIA) enabled to determine the exact content of actin in GAT nuclei and nuclear matrices – 5 g/ml in nuclei, of which 50% are bound to DNA and 3001o being a component of the protein part of the nuclear matrix. These results are supported by electron microscopic data, where immunogold technique was performed on thin sections and spread material. The applied methods suggest that part of the nuclear actin is tightly bound (resistant to 2 M NaCI) to DNA and represents a component of the internal nuclear matrix.     

Antibodies to Z DNA stabilized with polyarginine

The left-handed form of poly(dG-m5dC).poly(dG-m5dC) induced by heating the copolymer in the presence of magnesium and stabilized with polyarginine can be used to raise antibodies in rabbits. These antibodies are able to recognize the Z conformation of both methylated and nonmethylated forms of the copolymers. In the same experimental conditions, hypermethylated B DNA is not recognized by these antibodies.     

Plasma levels of vitamin A and its protein vectors (RBP and PA), carotene, total cholesterol and cholesterol-HDL in patients with dysplasia of the uterine cervix

In this study plasma levels of vitamin A, carotenoids, retinol binding protein (RBP), prealbumin (PA), HDL-and total cholesterol were determined in 19 female subjects with cervical dysplasia and compared to those of the healthy female subjects described in our previous research. Plasma levels of vitamin A and carotene were determined by a spectrophotometric method using trifluoroacetic acid, plasma RBP and PA by single radial immunodiffusion and HDL- and total cholesterol by enzymatic colorimetry. Plasma mean values of vitamin A and HDL-cholesterol were lower (P less than 0.05 and P less than 0.01, respectively) than in the control group. On the contrary total cholesterol was higher (P less than 0.01) in the patients than in the control group. Vitamin A plasma levels were significantly related (P less than 0.01) to RBP and PA. No significant statistical correlation was found between the severity of the dysplasia and vitamin A plasma levels.     

Effects of 5'deoxy-5'-methylthioadenosine on the metabolism of S-adenosyl methionine

The treatment of transformed rat cells with micromolar amounts of 5'deoxy 5'methyl thioadenosine induces rapid effects on the rate of methylation of DNA concomitantly with alterations of intracellular pools of S-adenosyl methionine and S-adenosyl homocysteine. Pulse chase labelling experiments indicate that 5'deoxy 5'methylthioadenosine does not inhibit the degradation of S-adenosyl homocysteine but inhibits the consumption of S-adenosyl methionine. In vitro transmethylation assays performed with heterologous DNA show that low doses of the thioethernucleoside do not significantly affect the DNA methyltransferase activity of cellular extracts. The biological role of 5'deoxy 5'methylthioadenosine, a natural molecule formed during the synthesis of polyamines is discussed.     

A Second Gene for Cerulean Cataracts Maps to the β Crystallin Region on Chromosome 22

Congenital cataracts are one of the most common major eye abnormalities and often lead to blindness in infants. At least a third of all cases are familial. Within this group, highly penetrant, autosomal dominant forms of congenital cataracts (ADCC) are most common. ADCC is a genetically heterogeneous group of disorders, in which at least eight different loci have been identified for nine clinically distinct forms. Among these, Armitageet al.(Nature Genet.9: 37–40, 1995) mapped a gene for cerulean blue cataracts to chromosome 17q24. Bodkeret al.(Am. J. Med. Genet.37: 54–59, 1990) described a large family with cerulean blue cataracts, in which the affected daughter of affected first cousins was presumed to be homozygous for the purported gene. We report linkage in this family to the region on chromosome 22q that includes two β crystallin genes (CRYBB2, CRYBB3) and one pseudogene (CRYBB2P1). The affected female in question is homozygous at all markers.     

General relation between variance-time curve and power spectral density for point processes exhibiting 1/f β-fluctuations,with special reference to heart rate variability

Counting statistics in the form of the variance-time curve provides an alternative to spectral analysis for point processes exhibiting 1/f ^β-fluctuations, such as the heart beat. However, this is true only for β<1. Here, the case of general β is considered. To that end, the mathematical relation between the variance-time curve and power spectral density in the presence of 1/f ^β-noise is worked out in detail. A modified version of the variance-time curve is presented, which allows us to deal also with the case β?1. Some applications to the analysis of heart rate variability are given.     

Copulatory mechanics in the wolf spider Agalenocosa pirity reveals a hidden diversity of locking systems in Lycosidae (Araneae)

Genital traits are among the fastest to evolve, and the processes that drive their evolution are intensively studied. Spiders are characterized by complex genitalia, but the functional role of the different structures during genital coupling is largely unknown. Members of one of the largest spider groups, the retrolateral tibial apophysis (RTA) clade, are characterized by a RTA on the male palp, which is thought to play a crucial role during genital coupling. However, the RTA was lost in several families including the species-rich wolf spiders (Lycosidae) leading to the hypothesis that the genital coupling is achieved by alternative mechanisms. Here, we investigate the genital interactions during copulation in the wolf spider Agalenocosa pirity (Zoicinae) on cryofixed mating pairs using electron, optical and X-ray microscopy and compare our findings with other lycosids and entelegyne spiders. We found an unprecedented coupling mechanism for lycosid spiders involving the palea and a membranous cuticle folding adjacent to the epigynal plate. Additionally, we show an uncommon coupling between the median apophysis and the contralateral genital opening, and confirmed that the terminal apophysis acts as functional conductor, as previously hypothesized for males of Zoicinae. Phylogenetic mapping of RTA indicated that the basal tibial process found in Agalenocosa is a secondary acquisition rather than a modified RTA.     

Corrosion of aluminum alloy 2024 by microorganisms isolated from aircraft fuel tanks

Abstract

Microorganisms frequently contaminate jet fuel and cause corrosion of fuel tank metals. In the past, jet fuel contaminants included a diverse group of bacteria and fungi. The most common contaminant was the fungus Hormoconis resinae. However, the jet fuel community has been altered by changes in the composition of the fuel and is now dominated by bacterial contaminants. The purpose of this research was to determine the composition of the microbial community found in fuel tanks containing jet propellant-8 (JP-8) and to determine the potential of this community to cause corrosion of aluminum alloy 2024 (AA2024). Isolates cultured from fuel tanks containing JP-8 were closely related to the genus Bacillus and the fungi Aureobasidium and Penicillium. Biocidal activity of the fuel system icing inhibitor diethylene glycol monomethyl ether is the most likely cause of the prevalence of endospore forming bacteria. Electrochemical impedance spectroscopy and metallographic analysis of AA2024 exposed to the fuel tank environment indicated that the isolates caused corrosion of AA2024. Despite the limited taxonomic diversity of microorganisms recovered from jet fuel, the community has the potential to corrode fuel tanks.     

Comparative bionomics of four populations of Meccus longipennis (Hemiptera: Reduviidae: Triatominae) under laboratory conditions

The values of biological parameters related to the life cycles of four populations of Meccus longipennis (Reduviidae: Triatominae) were evaluated. Cohorts of each of the four studied populations from different geographical areas of Mexico were maintained under similar laboratory conditions and then compared. The population from El Saucito de Araujo was different from the other three studied populations, which could help explain the secondary importance of M. longipennis in the state of Chihuahua. This paper also supports the proposition that biological traits are important criteria for determining relationships between populations.