Intramolecular domain-domain interactions and intermolecular self-association in bovine prothrombin. A potentiometric and laser light-scattering study

The interaction of bovine prothrombin with Ca²⁺ and Mg²⁺ ions was investigated by following H⁺ release as a function of metal ion concentration at pH 6 and pH 7.4 at high and low ionic strength. Prothrombin Ca²⁺ and Mg²⁺ binding is characterized by high- and low-affinity sites. M²⁺ binding at these sites is associated with intramolecular conformational changes and also with intermolecular self-association. The pH dependence of H⁺ release by M²⁺ is bell shaped and consistent with controlling pK_a values of 4.8 and 6.5. At pH 6 and low ionic strength, both Ca²⁺ and Mg²⁺ titrations following H⁺ release clearly show independent low- and high-affinity binding sites. Laser light scattering reveals that at pH 7.4 and low ionic strength, and at pH 6.0 and high ionic strength, the prothrombin molecular weight is between 73 and 98 kD. At pH 7.4 and high ionic strength, prothrombin is monomeric in the absence of metal ions, but appears to dimerize in the presence of M²⁺. At pH 6.0 and low ionic strength prothrombin exists as a dimer in the absence of metal ions and is tetrameric in the presence of Ca²⁺ and remains dimeric in the presence of Mg²⁺. These results and those for metal ion-dependent H⁺ release indicate that H⁺ release occurs concomitantly with association processes involving prothrombin.Abbreviations GLA -carboxyglutamic acid; fragment 1. amino terminal residues 1–156 of bovine prothrombin - MES 2-(N-morpholino) ethanesulfonic acid - MOPS 3-(N-morpholino) propanesulfonic acid - PS/PC phosphatidylserine/phosphatidylcholine vesicles - ionic strength     

Relationship between elevated lipid peroxides,vitamin E deficiency and hypertension in preeclampsia

Preeclampsia or pregnancy-induced hypertension is a major cause of both maternal and fetal-neonatal morbidity and mortality. The deficiency of vitamin E can cause accumulation of lipid peroxidation products, which, in turn, can induce vasoconstriction. This study has examined any evidence of increased cellular lipid peroxidation and accumulation of malonydialdehyde (MDA, an end product of lipid peroxidation) in pregnancy-induced hypertension and any relationship between the elevated MDA and lower vitamin E levels with hypertension in pregnant women. EDTA-Blood was collected from pregnant women at the time of delivery. Plasma vitamin E was determined by HPLC; MDA by the thiobarbituric acid-reactivity. Subjects with diastolic blood pressure(DBP) 90 mm Hg were considered hypertensive (HT) and with <90 mm Hg normotensive (NT). Data (Mean±SE) from 49 NT and 11 HT women show that HT has significantly lower vitamin E (22±1 vs 27±1 nmole/ml, p<0.03) and elevated MDA levels (0.56±0.06 vs 0.43±0.02 nmole/ml, p<0.03) compared to NT; the ages and gestational ages of women were similar. Among all women, there was a significant positive relationship between DBP and MDA levels (r=0.27, p<0.05), and a significant negative relationship between vitamin E levels and DBP (–0.36, p<0.005), and a significant negative relationship between MDA and vitamin E levels (r=–0.27, p<0.05). Thus, HT women's plasma has significantly lower E and higher MDA levels, and DBP significantly correlates with the extent of vitamin E deficiency and increased MDA levels. This study suggests a relationship between elevated lipid peroxidation and lower vitamin E levels and hypertension in pregnancy (preeclampsia).     

Mesodern-inducing factors and mesodermal patterning

Identification of the signalling molecules involved in mesoderm formation in amphibian embryos still presents problems. None of the original candidates, such as activin, have been definitively ruled out, and the new factors, such as the nodal-related genes, have come on to the scene. Of the original candidates, activin has been definitively shown to act as a morphogen, whereas bone morphogenetic protein (BMP)-4 has emerged as a ventral inducer and an inhibitor of neural differentiation. The effects of BMP-4 are antagonized by chordin, a molecule related to the product of the Drosophila gene short gastrulation.     

Comparison of Assimilatory Organic Nitrogen, Sulfur, and Carbon Sources for Growth of Methanobacterium Species

Experiments document the ability of two species of autotrophic methanogens to assimilate and utilize organic substrates as the nutrient sulfur or nitrogen source and as a carbon source during growth on H₂-CO₂. Methanobacterium thermoautotrophicum strain ΔH and the mesophilic species Methanobacterium sp. strain Ivanov grew with glutamine as the nitrogen source or cysteine as the sulfur source. M. thermoautotrophicum also utilized urea as the nitrogen source and as a carbon precursor for methane and cell synthesis. Methanobacterium sp. strain Ivanov grew with methionine as the sulfur source. The growth rate of two different Methanobacterium species was lower on an organic N or S source than on ammonium or sulfide. ³⁵S and ¹⁴C tracer studies demonstrated that amino acid or urea assimilation correlated with time and amount of growth. The rate of [³⁵S]cysteine incorporation was similar in strain ΔH (34 nmol h⁻¹ mg of cells⁻¹) and strain Ivanov (23 nmol h⁻¹ mg of cells⁻¹). However, the rate of [¹⁴C]acetate incorporation was dramatically different (17 versus 208 nmol h⁻¹ mg of cells⁻¹ in strains ΔH and Ivanov, respectively). [¹⁴C]acetate accounted for 1.3 and 21.2% of the total cell carbon synthesized by strains ΔH and Ivanov, respectively. Amino acids and urea were mainly assimilated into the cell protein fraction, but accounted for less than 2.0% of the total cell carbon synthesized. The data suggest that a biochemical-genetic approach to understanding cell carbon synthesis in methanogens is feasible; mutants that are auxotrophic for either acetate, glutamine, cysteine, or methionine are suggested as future targets for genetic studies.     

Allozyme variation and evolutionary relationships of grain amaranths (Amaranthus spp.)

Summary Allozyme studies in amaranth provided useful assays of genetic variation in order to verify the patterns inferred from morphological traits, for elucidating the genetic structure of landraces, and for the studies of evolutionary relationships among wild, weedy and crop species. Thirty-four populations of cultivated New World amaranths were surveyed along with 21 weedy New World populations for allozyme variation at nine electrophoretic enzyme loci. Eleven populations of cultivated amaranths from the Indian State of Uttar Pradesh and six from Nepal were also surveyed for a comparison. In the New World populations, heterozygosity was low, and different populations ranged from 0 to 44% polymorphic loci. Adjacent populations were often fixed for different alleles or had very different allele frequencies at certain loci, with no apparent geographical patterns. Diversity index H was partitioned into the intra- and interpopulation as well as the interspecific components of variability. The crop versus weed genetic distances were the largest, whereas the intra- and interpopulation components of H were about equal. Genetic structure of all three species of the New World amaranths together can be described as a collection of distinct populations, each more or less a heterogeneous collection of highly homozygous individuals. The North Indian populations showed relatively less allozyme variability with the most common alleles same as those of Mexican landraces. Alleles at several loci proved to be diagnostic of the crop and weed groups, and of the three individual crop species. Genetic distances based on pooled gene frequencies showed the three crop species to be generally more closely related inter se than they were to their putative weedy progenitor species, respectively (with the exception of the weed-crop pair A. quitensis and A. caudatus). This implies a single domestication event involving A. hybridus as the common ancestor rather than three separate domestication events. Close similarity between A. caudatus and A. quitensis might have resulted from transdomestication based on a weedy or semi-domesticated species having migrated from Meso-America to South America. This preliminary report must now be expanded by further ecogeographical, cytogenetic and population studies on new extensive collections from the areas of early domestication. Some evidence of recent introgression and/or segregation of crop-weed hybrids between A. caudatus and A. retroflexus is available in the form of rare individuals in crop populations with crop allozyme genotypes except for a single homozygous weedy allele.     

Charge-transfer complexes of some linear conjugated polyenes.

On adsorption of some electron-acceptor molecules on the solid films of all-trans-beta-carotene, beta-apo-8'-carotenal, astacene and methylbixin a new absorption band appears on the longer-wavelength side of the spectrum in addition to the original bands. The position of this new band is dependent on the electron affinity (EA) of the acceptor molecules, and the intensity of this band increases with the amount of adsorbed acceptor molecules. A linear relationship between the vmax. of the new band and EA was observed. The value of the ionization potential of the polyenes estimated from such linear relationship agrees satisfactorily with the value obtained by other methods. It has been concluded that the polyenes behave as electron donor and first form molecular charge-transfer complexes (of type [polyene . I2] with iodine) with electron acceptors, these finally dissociating to yield ionic complexes (of type [polyene . I+] with iodine).     

A T cell nuclear factor resembling NF-AT binds to an NF-kappa B site and to the conserved lymphokine promoter sequence "cytokine-1".

Nuclear extracts from a nontransformed murine T lymphocyte clone contained two inducible factors that bound to a nuclear factor kappa B (NF-kappa B) site. One factor was NF-kappa B, and the other was differentiated from NF-kappa B by its mobility in the electrophoretic mobility shift assay and its lack of sensitivity to protein kinase C depletion. Competition and methylation interference assays showed that the binding site for the novel factor was limited to nucleotides in the 3' half of the kappa B site. This part of the kappa B site resembled sequences in the binding site for a second inducible nuclear factor of T cells, NF-AT, as well as a conserved sequence found in several lymphokine genes, termed "cytokine-1" (CK-1). Competition and methylation interference analysis showed that both NF-AT and CK-1 sequences bound a factor similar to the novel kappa B-binding factor and that binding involved a four-nucleotide sequence (TTCC) that the kappa B, CK-1, and NF-AT sites have in common. The complexes that form with each site have characteristics of NF-AT: they are induced upon T cell receptor stimulation, are sensitive to protein synthesis inhibitors and cyclosporin A, and are not sensitive to protein kinase C depletion. Thus, a factor or factors similar to NF-AT can bind to three distinct promoter sequences which occur commonly in several T cell activation genes. These results raise the possibility that related factors binding to kappa B, CK-1, and NF-AT sequences could play a role in the coordinate induction of T cell activation genes. In addition, our results suggest that kappa B and CK-1 sites represent potential cyclosporin-sensitive promoter elements by virtue of their ability to bind an NF-AT-like factor.     

Synthesis of oligosaccharides containing the X-antigenic trisaccharide (alpha-L-Fucp-(1----3)-[beta-D-Galp-(1----4)]-beta-D-GlcpNAc) at their nonreducing ends.

The "armed" methyl 2,3,4-tri-O-benzyl-1-thio-beta-L-fucopyranoside was reacted with "disarmed" phenyl O-(tetra-O-acetyl-beta-D-galactopyranosyl)-(1----4)-6-O-benzyl-2- deoxy-2-phthalimido-1-thio-beta-D-glucopyranoside in the presence of CuBr2-Bu4NBr complex to give phenyl O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-(1----4)-O- [(2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl)-(1----3])-6-O-benzyl-2-deoxy -2- phthalimido-1-thio-beta-D-glucopyranoside (6) as a novel glycosyl donor. The glycosylating capability of 6 was further examined using N-iodosuccinimide-triflic acid as a reagent. This led to the synthesis of a tetrasaccharide and a pentasaccharide incorporating the X-antigenic structure represented by 6.     

Oxidative fermentation of calcium-magnesium lactate to calcium-magnesium acetate deicing salt

Summary The oxidation of Ca–Mg lactate to Ca–Mg acetate (CMA) deicing salt was studied in pure cultures ofAcetobacter pasteurianus, Gluconobacter cerinus orG. oxydans. Gluconobacter sp., which maintained a practically self-controlled pH reaction and did not overoxidize acetate, appear to be potentially important for CMA production.     

Bancroftian microfilariasis in association with pulmonary tuberculosis. Report of a case with diagnosis by fine needle aspiration

A 25-year-old man presented with clinical and radiologic features suggestive of pulmonary tuberculosis. Since the examination of Ziehl-Neelsen-stained sputum smears for acid-fast bacilli was repeatedly negative, a transthoracic fine needle aspiration biopsy was performed. Papanicolaou-stained smears of the aspirate showed microfilariae of Wuchereria bancrofti and a tuberculous exudate but no acid-fast bacilli or classic granulomas. Subsequent sputum samples did show acid-fast bacilli, while a nocturnal peripheral blood sample showed microfilariae.