Autoantibody to vasoactive intestinal peptide in human circulation

In a radioassay for Vasoactive Intestinal Peptide (VIP)-binding, eight out of 33 plasma samples from healthy human subjects exhibited specific binding ranging from 2.6% to 46.7% of total [125 I]VIP. This binding was competitively displaced by unlabeled VIP. The structurally homologous peptides, Peptide Histidine Isoleucine (PHI) and secretin, were, respectively, 72-fold and 413-fold less potent than VIP in displacing bound [125 I]VIP, whereas the unrelated peptides, neurotensin, eledoisin, bombesin and metenkephalin, were without effect on the binding. The antibody nature of the VIP-binding factor was suggested by its precipitation with ammonium sulfate, attenuation after absorption with Staphylococcus aureus preparations, precipitation with antisera against human IgG and IgM, and coelution with standard IgG and IgM on anion-exchange and high-performance gel-filtration columns. Pepsin treatment of purified IgG fraction yielded a VIP-binding species with apparent molecular weight of 108 +/- 13 kDa that was precipitated by antiserum against the F(ab)2 fragment of the IgG molecule. These results demonstrate the existence in some human plasmas of an autoantibody that binds VIP.     

Some characteristics of pollen wall cytochemistry and ultrastructure in Japanese larch (Larix leptolepis Gord.)

Summary The mature pollen of Larix leptolepis Gord. (Conifer) contains five different cell types, and the plasma membrane of the vegetative cell is continuous and organized. The pollen wall is composed of two morphologically and cytochemically distinct domains: the exine and the intine. In the multilayered exine, the ektexine appears granular and the endexine, lamellar. The intine is thick and bilayered with a microfibrillar structure occupying its inner portion. Cytochemical reactions of the exine and the intine are similar to those found in angiosperms. Pollen wall involvement in the male female recognition system is discussed with respecl to the angiosperms.     

Population genetic structure and connectivity of the seagrass Thalassia hemprichii in the Western Indian Ocean is influenced by predominant ocean currents

This study is the first large‐scale genetic population study of a widespread climax species of seagrass, Thalassia hemprichii, in the Western Indian Ocean (WIO). The aim was to understand genetic population structure and connectivity of T. hemprichii in relation to hydrodynamic features. We genotyped 205 individual seagrass shoots from 11 sites across the WIO, spanning over a distance of ~2,700 km, with twelve microsatellite markers. Seagrass shoots were sampled in Kenya, Tanzania (mainland and Zanzibar), Mozambique, and Madagascar: 4–26°S and 33–48°E. We assessed clonality and visualized genetic diversity and genetic population differentiation. We used Bayesian clustering approaches (TESS) to trace spatial ancestry of populations and used directional migration rates (DivMigrate) to identify sources of gene flow. We identified four genetically differentiated groups: (a) samples from the Zanzibar channel; (b) Mozambique; (c) Madagascar; and (d) the east coast of Zanzibar and Kenya. Significant pairwise population genetic differentiation was found among many sites. Isolation by distance was detected for the estimated magnitude of divergence (D_EST), but the three predominant ocean current systems (i.e., East African Coastal Current, North East Madagascar Current, and the South Equatorial Current) also determine genetic connectivity and genetic structure. Directional migration rates indicate that Madagascar acts as an important source population. Overall, clonality was moderate to high with large differences among sampling sites, indicating relatively low, but spatially variable sexual reproduction rates. The strongest genetic break was identified for three sites in the Zanzibar channel. Although isolation by distance is present, this study suggests that the three regionally predominant ocean current systems (i.e., East African Coastal Current, North East Madagascar Current, and the South Equatorial Current) rather than distance determine genetic connectivity and structure of T. hemprichii in the WIO. If the goal is to maintain genetic connectivity of T. hemprichii within the WIO, conservation planning and implementation of marine protection should be considered at the regional scale—across national borders.     

Non-peptidic substrate-mimetic inhibitors of Akt as potential anti-cancer agents

Akt has emerged as a critical target for the development of anti-cancer therapies. It has been found to be amplified, overexpressed, or constitutively activated in numerous human malignancies with oncogenesis derived from the simultaneous promotion of cell survival and suppression of apoptosis. A valuable alternative to the more common ATP-mimetic based chemotherapies is a substrate-mimetic approach, which has the potential advantage of inherent specificity of the substrate-binding pocket. In this paper we present the development of high affinity non-peptidic, substrate-mimetic inhibitors based on the minimum GSK3β substrate sequence. Optimization of initial peptidic leads resulted in the development of several classes of small molecule inhibitors, which have comparable potency to the initial peptidomimetics, while eliminating the remaining amino acid residues. We have identified the first non-peptidic substrate-mimetic lead inhibitors of Akt 29a–b, which have affinities of 17 and 12 μM, respectively. This strategy has potential to provide a useful set of molecular probes to assist in the validation of Akt as a potential target for anti-cancer drug design.     

Effect of chronic hyperoxic exposure on duroquinone reduction in adult rat lungs

NAD(P)H:quinone oxidoreductase 1 (NQO1) plays a dominant role in the reduction of the quinone compound 2,3,5,6-tetramethyl-1,4-benzoquinone (duroquinone, DQ) to durohydroquinone (DQH2) on passage through the rat lung. Exposure of adult rats to 85% O2 for > or =7 days stimulates adaptation to the otherwise lethal effects of >95% O2. The objective of this study was to examine whether exposure of adult rats to hyperoxia affected lung NQO1 activity as measured by the rate of DQ reduction on passage through the lung. We measured DQH2 appearance in the venous effluent during DQ infusion at different concentrations into the pulmonary artery of isolated perfused lungs from rats exposed to room air or to 85% O2. We also evaluated the effect of hyperoxia on vascular transit time distribution and measured NQO1 activity and protein in lung homogenate. The results demonstrate that exposure to 85% O2 for 21 days increases lung capacity to reduce DQ to DQH2 and that NQO1 is the dominant DQ reductase in normoxic and hyperoxic lungs. Kinetic analysis revealed that 21-day hyperoxia exposure increased the maximum rate of pulmonary DQ reduction, Vmax, and the apparent Michaelis-Menten constant for DQ reduction, Kma. The increase in Vmax suggests a hyperoxia-induced increase in NQO1 activity of lung cells accessible to DQ from the vascular region, consistent qualitatively but not quantitatively with an increase in lung homogenate NQO1 activity in 21-day hyperoxic lungs. The increase in Kma could be accounted for by approximately 40% increase in vascular transit time heterogeneity in 21-day hyperoxic lungs.     

Effect of nutrition and endoparasitic treatment on growth, onset of puberty and reproductive activity in Menz ewe lambs

Ewe lambs of the Ethiopian Menz breed were assigned at weaning (90+/-3 days) to four levels of nutrition (poor, low, medium and high) to achieve different premating growth rates with or without treatment for endoparasites. A concentrate mixture providing 2.5 Mcal/kg dry matter (DM) metabolizable energy and 15.2 g/kg DM digestible protein was used. Improved nutrition increased lamb postweaning average daily weight gain up to puberty by 6 to 26 g/day and the conception rate to first estrus by 9 to 16% while it reduced the mortality rate by 24 to 31% and age at first lambing by 2 to 5 months. Lambs reached puberty (age at first estrus) at 16.9+/-0.1 kg (+/-SEM) or 60% of mature body weight and 350+/-12 days of age. The onset of puberty was advanced by weaning weight (P<0.05), itself being well correlated with birth weight (r = 0.51, P<0.001), and by level of nutrition (high=299+/-19, medium=301+/-18, low=383+/-23 and poor=454+/-31 days, P<0.001) through enhanced growth rate (r = -0.82, P<0.001). No independent effect of drenching for endoparasites on pubertal development was observed (P>0.05), but its interaction with season-of-birth improved the growth of lambs born during the period of short rains (P<0.05). Overall mean litter size at first lambing was 1.07; the twinning rate was 6.5% and the birth weight was 1.9+/-0.1 kg. Up to 13.4% of newborn lambs, averaging 1.3+/-0.6 kg, died on the day of parturition. The results indicate that improved growth rate and body weight, resulting from better postweaning nutrition, affects the attainment of puberty in Menz ewe lambs. Mitigation of nutrition stress and endoparasitic infection depending on season-of-birth would thus increase the annual reproductive rate of breeding ewes and flock productivity.