The major herpes simplex virus DNA-binding protein holds single-stranded DNA in an extended configuration

Properties of the major DNA-binding protein found in herpes simplex virus-infected cells were investigated by using a filter binding assay and electron microscopy. Filter binding indicated that the stoichiometry of binding of the protein with single-stranded DNA is approximately 40 nucleotides per protein molecule at saturation. Strong clustering of the protein in DNA-protein complexes, indicative of cooperative binding, was seen with the electron microscope. Measurements of single-stranded fd DNA molecules saturated with protein and spread for electron microscopy by using both the aqueous and formamide spreading techniques indicated that the DNA is held in an extended configuration with a base spacing of approximately 0.13 nm per base.     

Mutation of residues 423 (Met/Ile), 444 (Thr/Met), and 506 (Asn/Ser) confer cholesteryl esterase activity on rat lung carboxylesterase. Ser-506 is required for activation by cAMP-dependent protein kinase.

Site-directed mutagenesis is used to identify amino acid residues that dictate reported differences in substrate specificity between rat hepatic neutral cytosolic cholesteryl ester hydrolase (hncCEH) and rat lung carboxylesterase (LCE), proteins differing by only 4 residues in their primary sequences. Beginning with LCE, the substitution Met(423) --> Ile(423) alone or in combination with other mutations increased activity with p-nitrophenylcaprylate (PNPC) relative to more hydrophilic p-nitrophenylacetate (PNPA), typical of hncCEH. The substitution Thr(444) --> Met(444) was necessary but not sufficient for expression of cholesteryl esterase activity in COS-7 cells. The substitution Asn(506) --> Ser(506), creating a potential phosphorylation site, uniformly increased activity with both PNPA and PNPC, was necessary but not sufficient for expression of cholesteryl esterase activity and conferred susceptibility to activation by cAMP-dependent protein kinase, a property of hncCEH. The 3 mutations in combination were necessary and sufficient for expression of cholesteryl esterase activity by the mutated LCE. The substitution Gln(186) --> Arg(186) selectively reduced esterase activity with PNPA and PNPC but was not required for cholesteryl esterase activity. Homology modeling from x-ray structures of acetylcholinesterases is used to propose three-dimensional models for hncCEH and LCE that provide insight into the effects of these mutations on substrate specificity.     

Neutral glycosphingolipids of murine lymphoma EL-4

Neutral glycosphingolipids of murine T-lymphoma EL-4 were studied. The major glycolipid components were identified as GlcCer, LacCer, GgOse3Cer and GgOse4Cer. It has been shown for the first time that not only gangliosides but also neutral glycolipids are shed from the cell surface into the outer medium.     

Characteristics of carbohydrate metabolism in the rat liver in thiamine deficiency

Thiamine deficiency in rats induced by oxythiamine is accompanied by an increase in the free NADP+/NADPH ratio in liver tissue, which results in multifold stimulation of the metabolite flux in the oxidation branch of the pentose cycle. The increase in the intracellular concentrations of isocitrate and alpha-ketoglutarate with a simultaneous decrease of malate in the liver of vitamin-deficient rats points to the inhibition of alpha-ketoglutarate dehydrogenase responsible for the anomalous metabolism under conditions of thiamine deficiency. The decrease of the functional activity of the tricarboxylic acid cycle is concomitant with the activation of conversions in the oxidation branch of the pentose cycle, glucuronate and glycolytic pathways of carbohydrate metabolism, which is directed at eliminating the energy deficiency in rats with B1-hypovitaminosis.     

An unusual pontine mass lesion.

A 27-year-old Puerto Rican man presented to Yale-New Haven Hospital with a six-week history of left-sided headache, diplopia, and drooping of the left side of his face. Cerebrospinal fluid examination showed a lymphocytic pleocytosis and a CT scan of the brain revealed an unusual intrapontine mass lesion requiring systemic antifungal therapy. This case emphasizes many of the diagnostic and therapeutic considerations required for effective therapy of fungal disease in the central nervous system.     

Benzene and the risk of non-Hodgkin lymphoma: A review and meta-analysis of the literature

Benzene, an accepted leukemogen, has been suggested to cause other hemato- and lymphopoietic cancers. Here we review the published literature for non-Hodgkin lymphoma (NHL) and occupational exposure to benzene. Six cohorts, sixteen case–control studies and two studies of other designs were identified through keyword searches of bibliographic databases. Twenty-two of twenty-four studies found no association between NHL and ever exposed to benzene compared to never; a random-effects meta-analysis gave a pooled risk estimate of 1.11 (95% confidence interval 0.94–1.30). Our finding of no effect agrees with one of two previous meta-analyses. The other meta-analysis examined if high benzene exposure increased NHL risk but a lack of consistent exposure categories within the same metric should have precluded pooling risks by exposure level. Instead, we reviewed whether dose–response relationships existed. The best available data came from six studies where exposure was estimated from historical measurements and on the whole, no trends in risks of NHL with rising cumulative, average, peak, or duration of benzene exposure were found. NHL is a heterogeneous group of malignancies and although less well-studied, benzene was not associated with any NHL subtype. In conclusion, benzene at either low or high doses does not increase the risk of NHL.     

Studies on human uterine cervix and rat uterus using S-, X- and Q-band electron-spin-resonance spectroscopy.

In previous studies we have reported on the detection of a strong e.s.r. signal in samples of normal human cervix; the signal is much reduced or absent in samples of invasive cancer of the cervix. In order to identify the species responsible for the strong signal, we have used X-, S- and Q-band e.s.r. spectroscopy. The major signal that is detectable in ground-up samples of cervix preserved at -196 degrees C has features consistent with the presence of a peroxy free radical. Good agreement with the experimental findings was obtained by computer simulation, using values for the g-tensor of gx = 2.002, gy = 2.005 and gz = 2.036. The peroxy radical is produced on grinding the normal cervix samples to a powder under liquid N2, and appears to be formed by modification of a pre-existing oxygen-containing complex. Control experiments eliminated the possibility that the strong signals seen in frozen powders prepared from normal cervix were artefacts only of the grinding procedure. Experiments with rats in vivo and with cervix samples in vitro are consistent with the conclusion that the peroxy radical is formed by disturbing the cyclo-oxygenase system that is involved in prostaglandin synthesis.     

Recent decrease in carbon sink to Russian forests

Regional Evaluation of Carbon Budget of Forests (RECBF), was used to study the dynamics of carbon balance in Russian forests in 1988–2015. The carbon sink (excess of absorption over losses) to forests was minimal in 1988. Since the first half of the 1990s, its increase has started. This increase was associated with the reduction of logging volume in connection with socioeconomic reforms. Since 2008, the carbon sink was gradually reduced due to increasing losses in logging operations, forest fires, and decreased carbon absorption.