Crystal structure of human PACRG in complex with MEIG1 reveals roles in axoneme formation and tubulin binding

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Enzymic synthesis,chemical characterisation and Sda activity of GalNAcß1-4[NeuAcα2-3]Galß1-4GlcNAc and GalNAcß1-4[NeuAcα2-3]Galß1-4Glc

The tetrasaccharides GalNAcß1-4[NeuAc2-3]Galß1-4Glc and GalNAcß1-4[NeuAc2-3]Galß1-4GlcNAc were synthesised by enzymic transfer of GalNAc from UDP-GalNAc to 3-sialyllactose (NeuAc2-3Galß1-4Glc) and 3-sialyl-N-acetyllactosamine (NeuAc2-3Galß1-4GlcNAc). The structures of the products were established by methylation and¹H-500 MHz NMR spectroscopy. In Sd^a serological tests the product formed with 3-sialyl-N-acetyllactosamine was highly active whereas that formed with 3-sialyllactose had only weak activity.     

Effect of colchicine on lysosomal structures in maturation-ameloblasts of the rat incisor

Summary The lysosomal systems in maturation-ameloblasts affected by colchicine were examined using trimetaphosphatase cytochemistry. Demineralized segments of rat incisor were incubated for trimetaphosphatase. At all time intervals, lysosomal structures exhibited reduced enzyme reactivity and were clustered in the Golgi region of the cell. Both ruffle-ended and smooth-ended ameloblasts maintained essentially normal morphology up to 4 h after colchicine injection, except for some migration of organelles. After 8 h, the ruffled border was markedly modified and the associated dense granular material was no longer present. Changes in the lysosomal system and ruffled border indicate interference by colchicine with a putative resorptive function of the maturation-ameloblasts.     

Approaches to breeding for salinity tolerance - a case study on Porteresia coarctata

Cereals are the world's major source of food for human nutrition. Among these, rice (Oryza sativa) is the most prominent and represents the staple diet for more than two-fifths (2.4 billion) of the world's population, making it the most important food crop of the developing world (Anon., 2000a). Rice production in vast stretches of coastal areas is hampered due to high soil salinity. This is because rice is a glycophyte and it does not grow well under saline conditions. In order to increase rice production in these areas there is a need to develop rice varieties suited to saline environments. Research has shown that Porteresia coarctata, a highly salt tolerant wild relative of rice growing in estuarine soils, is an important material for transferring salt tolerant characteristics to rice. It is quite possible that Porteresia may be used as a parent for evolving better and truly salt resistant varieties. The inadequate results and the difficulties associated with conventional breeding techniques necessitate the use of the tools of crop biotechnology in unravelling some of the characteristics of Porteresia that have been highlighted in this report. In view of the limited resources available for increasing salinity tolerance to the breeders to wild rice germplasm, Porteresia is undoubtedly one of the key source species for elevating salinity tolerance in cultivated rice.     

Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Chemical modification of membrane proteins in relation to inhibition of anion exchange in human red blood cells

Mono-, di-, and trisulfonic acids, including 4,4′-diacetamido stilbene-2,2′-disulfonic acid (DAS) and 2-(4′-amino phenyl)-6-methylbenzene thiazol-3′,7-disulfonic acid (APMB) produce a reversible inhibition of sulfate equilibrium exchange in human red cells. A study of the sidedness of the action of a number of these sulfonic acids in red cell ghosts revealed that some, like DAS, inhibit only at the outer membrane surface while others, like APMB, inhibit at either surface. This finding suggests that at least two different types of membrane sites are involved in the control of anion permeability. The nature of the anion permeability controlling sites in the outer cell surface was investigated by studying the effects of DAS on the inhibition by dinitrofluoro-benzene (DNFB) of anion equilibrium exchange and on the binding of DNFB to the proteins of the red blood cell membrane. After exposure to DNFB in the presence of DAS for a certain period of time, there was a reduction of both the inhibitory effect of DNFB on sulfate exchange and the binding of DNFB to the protein in band 3 of SDS polyacrylamide gel electropherograms (nomenclature of Steck, J. Cell. Biol., 62: 1, 1974). Since binding to other membrane proteins was not affected, this observation supports the assumption that the protein in band 3 plays some role in anion transport. In accordance with the absence of an inhibitory effect at the inner membrane surface, internal DAS does not affect DNFB binding to the protein in band 3. DAS protected the anion exchange system not only against inhibition by DNFB but also by m-isothiocyanato benzene sulfonic acid. In contrast to DAS, the equally inhibitory phlorizin does not reduce the rate of dinitrophenylation of the protein in band 3. This suggests that either not all inhibitors of anion exchange exert their action by a combination with sites on the protein in band 3 or that in spite of the described evidence this protein is not involved in the control of anion movements. The effect of the irreversibly binding inhibitor 4-acetamido-4′-isothiocyanato-stilbene-2,2′-disulfonic acid (SITS) on DNFB binding to the protein in band 3 was studied in an attempt to differentiate DNFB binding related to inhibition of anion permeability from DNFB binding which is not involved. At least three distinguishable populations of DNFB binding sites were found: (1) binding sites common for DNFB and SITS which are probably related to inhibition, (2) other common sites which are not related to inhibition and (3) different sites whose dinitrophenylation is not affected by SITS. The number of sites in population (1) was estimated to be 0.8–1.2 ± 10⁶/cell. A study of the concentration dependence of the inhibition of anion equilibrium exchange with 4,4′-isothiocyanato-2,2′-stilbene disulfonic acid (DIDS) and APMB further suggests that among the sites in population (1) a major fraction is susceptible to modification by APMB and DIDS while the rest is only susceptible to DIDS. It remains undecided whether these differences of susceptibility reflect differences of accessibility or reactivity.     

Synthesis,Reactions, and Antimicrobial Activity of Novel Heterocyclic Compounds Containing Cyclopenta[d]thieno[2,3-b]pyridine Moiety and Related Fused Heterocycles

Russian Journal of Bioorganic Chemistry - We describe a simple method to synthesize novel 4-cyano-1-morpholin-4-yl-6,7-dihydro-5H-cyclopenta[c]pyridine-3-thione by the reaction of...     

Predation of potential insect pests in oil palm plantations,rubber tree plantations,and fruit orchards

In human‐modified landscapes, important ecological functions such as predation are negatively affected by anthropogenic activities, including the use of pesticides and habitat degradation. Predation of insect pests is an indicator of healthy ecosystem functioning, which provides important ecosystem services, especially for agricultural systems. In this study, we compare predation attempts from arthropods, mammals, and birds on artificial caterpillars in the understory, between three tropical agricultural land‐use types: oil palm plantations, rubber tree plantations, and fruit orchards. We collected a range of local and landscape‐scale data including undergrowth vegetation structure; elevation; proximity to forest; and canopy cover in order to understand how environmental variables can affect predation. In all three land‐use types, our results showed that arthropods and mammals were important predators of artificial caterpillars and there was little predation by birds. We did not find any effect of the environmental variables on predation. There was an interactive effect between land‐use type and predator type. Predation by mammals was considerably higher in fruit orchards and rubber tree than in oil palm plantations, likely due to their ability to support higher abundances of insectivorous mammals. In order to maintain or enhance natural pest control in these common tropical agricultural land‐use types, management practices that benefit insectivorous animals should be introduced, such as the reduction of pesticides, improvement of understory vegetation, and local and landscape heterogeneity.