The dialectic between globalization and localization: Economic restructuring,women and strategies of cultural reproduction

Dialectical Anthropology -     

A broadly active viral inhibitor in human and animal organ extracts and body fluids

To help assess the possibility that a newly described viral inhibitor from cell cultures might play a natural defensive role in vivo, its distribution and concentration in human and animal organ extracts and body fluids were investigated. The concentration of the inhibitor was high in human liver, heart muscle, splenic extracts, and human serum and milk. The inhibitor in the body was indistinguishable from a previously described inhibitor produced in cell cultures that was characterized by broad antiviral activity, lack of target cell species specificity, lack of induction of stable antiviral activity in cells, rapid reversibility of antiviral action, prevention of virus attachment, and stability at 100 degrees C. Sixteen virus plaque reduction units of the inhibitor diminished the yield of poliovirus in vitro by more than 1000-fold. Additional evidence that contact-blocking viral inhibitor (CVI) inhibits vaccinia virus attachment to cells is presented. A role for the inhibitor in natural defense against viral infections is possible.     

Transbilayer distributions of red cell membrane phospholipids in unilamellar vesicles

The phospholipid organization in unilamellar vesicles comprised of various purified phospholipid components of monkey erythrocyte membrane was ascertained using phospholipase A2 and trinitrobenzenesulfonic acid as external membrane probes. The vesicles were formed by sonication or detergent dialysis and fractionated by centrifugation or gel permeation chromatography. Experiments were done to confirm that the phospholipase A2 treatments did not cause lysis or induce fusion of the vesicles. This enzyme hydrolysed only the glycerophospholipids in the outer surface of the vesicles. The amounts of the external phospholipids determined by this enzymatic method were verified using the chemical probe, trinitrobenzenesulfonic acid. The choline-containing phospholipids and phosphatidylethanolamine localized randomly in the two surfaces of sonicated vesicles (outer diameter, about 30 nm), whereas phosphatidylserine preferentially distributed in the inner monolayer. This phosphatidylserine asymmetry virtually disappeared in detergent dialysed vesicles (outer diameter, about 45 nm). Furthermore, inclusion of cholesterol in both the types of vesicles resulted in more random glycerophospholipid distributions across the plane of vesicles bilayer, presumably due to the cholesterol-induced increases in the size of vesicles. These results demonstrate that the transbilayer distribution of erythrocyte membrane phospholipids in unilamellar vesicles are controlled mainly by the surface curvature rather than by interlipid interactions, and therefore suggest that phospholipid-phospholipid and phospholipid-cholesterol interactions should not play any significant role in determining the membrane phospholipid asymmetry in red cells. It is proposed that this asymmetry primarily originates from differential bindings of phospholipids with membrane proteins in the two leaflets of the membrane bilayer.     

Metalloproteinase inhibitors from bovine cartilage and body fluids

Inhibitors of the mammalian metalloproteinases, collagenase, proteoglycanase and gelatinase were isolated from bovine cartilage (extracts and culture medium) and bovine amniotic fluid and serum. These inhibitors either bind or do not bind to concanavalin-A--Sepharose, with Mr (gel filtration) of about 30 000 and 20 000, respectively. Cartilage and chondrocyte culture media contained only concanavalin-A-binding inhibitors whereas cartilage extracts contained only a non-binding inhibitor: serum and amniotic fluid contained both forms of inhibitory activities. In moist biochemical respects, particularly in their abilities to inhibit metalloproteinases, all of the inhibitors were found to be similar. It is concluded that the forms of the inhibitors that differ in Mr may be closely related to the tissue inhibitor of metalloproteinases (TIMP) previously purified from rabbit and human sources. These findings help to clarify other studies on collagenase inhibitors and support the concept that TIMP-like inhibitors may be important in the control of connective tissue degradation.     

Target antigens in malaria transmission blocking immunity

Malaria transmission blocking immunity has been found to operate against two distinct phases of development of malaria parasites in the mosquito midgut: (i) against the extracellular gametes and newly fertilized zygotes shortly after ingestion by a mosquito of parasitized blood and (ii) against the zygotes during their subsequent development into ookinetes. Immunity is antibody-mediated and stage-specific. A set of three proteins, synthesized in the gametocytes, expressed on the surface of the gametes and newly fertilized zygotes and subsequently shed during later transformation of the zygotes, has been identified as the target antigens of anti-gamete fertilization blocking antibodies. A single protein, synthesized and expressed on the zygote surface during its development to ookinetes, has been identified as the target of antibodies which block the development of the fertilized parasites in the mosquito. Immunization of human populations against gamete or zygote antigens, while not directly protecting an immunized individual from inflection, would reduce the transfer of malaria within the population. Such immunity, in addition to reducing the overall rate of malaria transmission, would, if combined with a vaccine against the asexual (disease-causing) stages, reduce the chance of selection of parasites that are resistant to the asexual vaccine by preventing their entry into the mosquito population.     

Axial ranking of residues in collagen in relation to edge association and fibril formation

In our earlier analysis of intermolecular interactions between collagen molecules, a major concern with the program employed is that it compared numbers of interactions between residues located on edges of defined, identical width and thus would not necessarily compare the same number of residues in each edge. This would be particularly true of some values of θ where well-defined vertical ranking of residues occurs. We have examined ranking of residues in relation to intermolecular edge association between bovine skin [α1(I)]₃ model collagen molecules by utilizing two different methods of counting intermolecular interactions between residues. The interaction peaks at θ = 27.69° and 36.00° are absent or relatively less intense in the plots obtained by utilizing radial distances between interacting residues instead of vertical bands of defined width. These studies suggest caution in accepting recently reported analyses of superhelix coiling of the collagen molecule which point to values of 27.69° or 36.00° for the twist of the superhelix. Although intramolecular interactions clearly point to interaction of collagen molecules at D intervals, they are insufficiently restricted in distribution to provide a reliable estimate of the superhelix angle by procedures so far employed.     

Ligandin: An adventure in Liverland

Summary Ligandin is an abundant soluble protein which has at 1/2 of 2–3 days, is induced by many drugs and chemicals, and is stabilized in the absence of thyroid hormone. The protein is strategically concentrated in cells associated with transport and detoxification of many endogenous ligands, such as bilirubin, and exogenous ligands, such as drugs and chemicals. The protein is a dimer in rat liver. Whether the dimer is a primary gene product or at least two genes are involved is not known. The protein has broad, low affinity catalytic activity as a GSH-S-transferase for many ligands having electrophilic groups and hydrophobic domains. It catalyzes formation of GSH conjugates, noncovalently binds some ligands prior to their biotransformation or excretion in bile, and covalently binds other ligands, such as activated carcinogens. Recent studies include the possible role of ligandin in chemical carcinogenesis, diagnosis of inflammatory and neoplastic disease of the liver and kidney, and participation in intracellular transport. Although some of the roles that have been outlined are speculative, any single function is important. The GSH-Stransferases are primitive enzymes and non specific binding proteins but it is precisely their simplistic design that allows such protean serviceability.Ligandin illustrates a group of hepatic disposal mechanisms which involve bulk transport of ligands. Although specific uptake and transport mechanisms have been described for several hormones which enter the hepatocyte in small quantities and regulate intermediary metabolism and, possibly, cell maturation, bulk transport of ligands into, through and out of the liver involves mechanisms which accomodate many metabolites, drugs and chemicals of diverse structure. The liver is bathed in sewage which contains what we ingest or are injected with and potentially toxic products of intestinal microorganisms. The chemical formulas of the many substances which are metabolized by the liver provide a horror show of potentially reactive and toxic metabolites, mutagens and carcinogens. Despite this alimentary Love Canal, we and our livers do remarkably well. These hepatic disposal mechanisms, as exemplified by ligandin, evolved in ancient times. They are present, albeit sluggishly, in insects and ancient elasmobranchs. Hepatic uptake and removal mechanisms of high capacity, modest affinity and broad substrate range permit us to live in what has probably always been a threatening world.Abbreviations DAB N,N-dimethyl-4-amino azobenzene - GSH reduced glutathione - BSP bromosulfophthalein - SDS sodium dodecyl sulfate     

Proleptonchoides southindiae n. gen., n. sp., a New Leptonchoid from South India

Proleptonchoides southindiae n. gen., n. sp. (Dorylaimida: Leptonchidae), is described from soil around false tobacco (Lobelia excelsa) and cardamom (Elettaria cardamomurn) in South India. P. southindiae is prodelphic, has a short constricted esophageal bulb and flanged odontophore, and is phylogenetically close to Proleptonchus.