Insertion of N-linked glycosylation sites in the variable regions of the human immunodeficiency virus type 1 surface glycoprotein through AAT triplet reiteration.

Variable regions with sequence length variation in the human immunodeficiency virus type 1 envelope exhibit an unusual pattern of codon usage with AAT, ACT, and AGT together composing > 70% of all codons used. We postulate that this distribution is caused by insertion of AAT triplets followed by point mutations and selection. Accumulation of the encoded amino acids (asparagine, serine, and threonine) leads to the creation of new N-linked glycosylation sites, which helps the virus to escape from the immune pressure exerted by virus-neutralizing antibodies.     

Allelic diversity at the Mhc-DP locus in rhesus macaques (Macaca mulatta)

Allelic diversity at the major histocompatibility complex class II DP locus of rhesus macaques was studied by sequencing exon 2 of Mamu-DPA1 and -DPB1 genes. The Mamu-DPA1 gene is apparently invariant, whereas the Mamu-DPB1 locus displays polymorphism. Here we report the characterization of 1 Mamu-DPA1 and 13 Mamu-DPB1 alleles which were compared with other available primate Mhc-DPA1 and -DPB1 sequences. As compared with Mhc-DRB and -DQB1, most codons for the contact residues in the antigen binding site of the primate Mhc-DPB1 gene have a relatively low degree of variation in encoding various types of amino acids. In contrast to Mhc-DRB and -DQB, the HLA- and Mamu-DPB1 sequences cluster in a species-specific manner in phylogenetic trees. Mhc-DPB1 polymorphisms, however, are inherited in a transspecies mode of evolution, as is demonstrated by the sharing of lineage members between closely related macaque species. The data demonstrate that the transspecies character of Mhc-DPB1 polymorphism was retained over much shorter periods of time as compared with its sister class II loci, Mhc-DQ and -DR.The nucleotide sequence data reported in this paper have been submitted to the EMBL nucleotide sequence database and have been assigned the accession numbers Z32402–Z32415     

Steroid radiommuoassay: contribution of standards to blank values

The sensitivity of the radioimmunoassay of steroids is considerably reduced by high blank values which may be derived in part from co-chromatographed standards. Blank levels approach the detection limit of the radioimmunoassay of aldosterone, testosterone and androstenedione when 10,000 dpm (30–35 pg) labeled steroids are used as reference standard. When 20 μg aldosterone, testosterone, or androstenedione is used as standard, blank levels of up to 12,800 pg were measured in the radioimmunoassay. Application of the standards on a separate strip does not improve the results. From our experiments it seems clear that contamination is transported by the solvent.     

Repeated oral administration of capsaicin increases anxiety-like behaviours with prolonged stress-response in rats

This study was conducted to examine the psycho-emotional effects of repeated oral exposure to capsaicin, the principal active component of chili peppers. Each rat received 1 mL of 0.02% capsaicin into its oral cavity daily, and was subjected to behavioural tests following 10 daily administrations of capsaicin. Stereotypy counts and rostral grooming were significantly increased, and caudal grooming decreased, in capsaicin-treated rats during the ambulatory activity test. In elevated plus maze test, not only the time spent in open arms but also the percent arm entry into open arms was reduced in capsaicin-treated rats compared with control rats. In forced swim test, although swimming duration was decreased, struggling increased in the capsaicin group, immobility duration did not differ between the groups. Repeated oral capsaicin did not affect the basal levels of plasma corticosterone; however, the stress-induced elevation of plasma corticosterone was prolonged in capsaicin treated rats. Oral capsaicin exposure significantly increased c-Fos expression not only in the nucleus tractus of solitarius but also in the paraventricular nucleus. Results suggest that repeated oral exposure to capsaicin increases anxiety-like behaviours in rats, and dysfunction of the hypothalamic-pituitary-adrenal axis may play a role in its pathophysiology.     

Effect of weight loss and exercise on angiogenic factors in the circulation and in adipose tissue in obese subjects

Background:

Vascular growth is a prerequisite for adipose tissue (AT) development and expansion. Some AT cytokines and hormones have effects on vascular development, like vascular endothelial growth factor (VEGF‐A), angiopoietin (ANG‐1), ANG‐2 and angiopoietin‐like protein‐4 (ANGPTL‐4).

Methods:

In this study, the independent and combined effects of diet‐induced weight loss and exercise on AT gene expression and proteins levels of those angiogenic factors were investigated. Seventy‐nine obese males and females were randomized to: 1. Exercise‐only (EXO; 12‐weeks exercise without diet‐restriction), 2. Hypocaloric diet (DIO; 8‐weeks very low energy diet (VLED) + 4‐weeks weight maintenance diet) and 3. Hypocaloric diet and exercise (DEX; 8‐weeks VLED + 4‐weeks weight maintenance diet combined with exercise throughout the 12 weeks). Blood samples and fat biopsies were taken before and after the intervention.

Results:

Weight loss was 3.5 kg in the EXO group and 12.3 kg in the DIO and DEX groups. VEGF‐A protein was non‐significantly reduced in the weight loss groups. ANG‐1 protein levels were significantly reduced 22‐25% after all three interventions (P < 0.01). The ANG‐1/ANG‐2 ratio was also decreased in all three groups (P < 0.05) by 27‐38%. ANGPTL‐4 was increased in the EXO group (15%, P < 0.05) and 9% (P < 0.05) in the DIO group. VEGF‐A, ANG‐1, and ANGPTL‐4 were all expressed in human AT, but only ANGPTL‐4 was influenced by the interventions.

Conclusions:

Our data show that serum VEGF‐A, ANG‐1, ANG‐2, and ANGPTL‐4 levels are influenced by weight changes, indicating the involvement of these factors in the obese state. Moreover, it was found that weight loss generally was associated with a reduced angiogenic activity in the circulation.     

Effect of chronic treatment with Rosiglitazone on Leydig cell steroidogenesis in rats: <Emphasis Type="Italic">In vivo</Emphasis> and <Emphasis Type="Italic">ex vivo</Emphasis> studies

Background  

The present study was designed to examine the effect of chronic treatment with rosiglitazone - thiazolidinedione used in the treatment of type 2 diabetes mellitus for its insulin sensitizing effects - on the Leydig cell steroidogenic capacity and expression of the steroidogenic acute regulatory protein (StAR) and cholesterol side-chain cleavage enzyme (P450scc) in normal adult rats.     

First detection, isolation and molecular characterization of infectious salmon anaemia virus associated with clinical disease in farmed Atlantic salmon (Salmo salar) in Chile

Background  

Several forms of progressive retinal atrophy (PRA) segregate in more than 100 breeds of dog with each PRA segregating in one or a few breeds. This breed specificity may be accounted for by founder effects and genetic drift, which have reduced the genetic heterogeneity of each breed, thereby facilitating the identification of causal mutations. We report here a new form of PRA segregating in the Border Collie breed. The clinical signs, including the loss of night vision and a progressive loss of day vision, resulting in complete blindness, occur at the age of three to four years and may be detected earlier through systematic ocular fundus examination and electroretinography (ERG).     

Microbial boundstone dominated carbonate slope (Upper Carboniferous,N Spain): Microfacies,lithofacies distribution and stratal geometry

Summary The Carboniferous, particularly during the Serpukhovian and Bashkirian time, was a period of scarce shallow-water calcimicrobial-microbialite reef growth. Organic frameworks developed on high-rising platforms are, however, recorded in the Precaspian Basin subsurface, Kazakhstan, Russia, Japan and Spain and represent uncommon occurrences within the general trend of low accumulation rates and scarcity of shallow-water reefs. Sierra del Cuera (Cantabrian Mountains, N Spain) is a well-exposed high-rising carbonate platform of Late Carboniferous (Bashkirian-Moscovian) age with a microbial boundstone-dominated slope dipping from 20° up to 45°. Kilometer-scale continuous exposures allow the detailed documentation of slope geometry and lithofacies spatial distribution. This study aims to develop a depositional model of steep-margined Late Paleozoic platforms built by microbial carbonates and to contribute to the understanding of the controlling factors on lithofacies characteristics, stacking patterns, accumulation rates and evolution of the depositional architecture of systems, which differ from light-dependent coralgal platform margins. From the platform break to depths of nearly 300 m, the slope is dominated by massive cement-rich boundstone, which accumulated through the biologically induced precipitation of micrite. Boundstone facies (type A) with peloidal carbonate mud, fenestellid and fistuliporid bryozoans, sponge-like molds and primary cavities filled by radiaxial fibrous cement occurs all over the slope but dominates the deeper settings. Type B boundstone consists of globose centimeter-scale laminated accretionary structures, which commonly host botryoidal cement in growth cavities. The laminae nucleate around fenestellid bryozoans, sponges, Renalcis and Girvanella-like filaments. Type B boundstone typically occurs at depths between 20–150 m to locally more than 300 m and forms the bulk of the Bashkirian prograding slope. The uppermost slope boundstone (type C; between 0 and 20–100 m depth) includes peloidal micrite, radiaxial fibrous cement, bryozoans, sponge molds, Donezella, Renalcis, Girvanella, Ortonella, calcareous algae and calcitornellid foraminifers. From depths of 80–200 m to 450 m, 1–30 m thick lenses of crinoidal packstone, spiculitic wackestone, and bryozoan biocementstone with red-stained micrite matrix are episodically intercalated with boundstone and breccias. These layers increase in number from the uppermost Bashkirian to the Moscovian in parallel with the change from a rapidly prograding to an aggrading architecture. The red-stained strata share comparable features with Lower Carboniferous deeper-water mud-mound facies and were deposited during relative rises of sea level and pauses in boundstone production. Rapid relative sea-level rises might have been associated with changes in oceanographic conditions not favourable for thecalcimicrobial boundstone growth, such as upwelling of colder, nutrient-rich waters lifting the thermocline to depths of 80–200 m. Downslope of 150–300 m, boundstones interfinger with layers of matrix-free breccias, lenses of matrix-rich breccias, platform- and slope-derived grainstone and crinoidal packstone. Clast-supported breccias bound by radiaxial cement are produced by rock falls and avalanches coeval to boundstone growth. Matrix-rich breccias are debris flow deposits triggered by the accumulation of red-stained layers. Debris flows develop following the relative sea-level rises, which favour the deposition of micrite-rich lithofacies on the slope rather than being related to relative sea-level falls and subaerial exposures. The steep slope angles are the result of in situ growth and rapid stabilization by marine cement in the uppermost part, passing into a detrital talus, which rests at the angle of repose of noncohesive material. In the Moscovian, the aggradational architecture and steeper clinoforms are the result of increased accommodation space due to tectonic subsidence and due to a reduction of slope accumulation rates (from 240±45−605±35 m/My to 130±5 m/My). The increasing number of red-stained layers and the decrease of boundstone productivity are attributed to environmental changes in the adjacent basin, in particular during relative rises of sea level and to possible cooling due to icehouse conditions. The geometry of the depositional system appears to be controlled by boundstone growth rates. During the Bashkirian, the boundstone growth potential is at least 10 times greater than average values for ancient carbonate systems. The slope progradation rates (nearly 400–1000 m/My) are similar to the highest values deduced for the Holocene Bahamian prograding platform margin. The fundamental differences with modern systems are that progradation of the microbial-boundstone dominated steep slope is primarily controlled by boundstone growth rates rather than by highstand shedding from the platform top and that boundstone growth is largely independent from light and controlled by the physicochemical characteristics of seawater.     

三氧化二砷对食管癌细胞增殖和热休克蛋白70表达的影响

目的：研究三氧化二砷（As2O3）对食管癌细胞增殖和热休克蛋白70（HSP70）表达的影响。方法：通过相差显微镜、流式细胞术、免疫细胞化学染色和免疫印迹分析等方法观察As2O3对人食管癌细胞株EC1的作用效果和作用机制。结果：与对照组相比,经2μmol/L和5μmol/Las2O3作用的细胞出现明显的生长抑制,G2/M期细胞比例增加;2μmol/Las2O3作用48h后经Ecl细胞HSP70（heat shock protein70）及HSC70(heat shock cognate protein70)表达均增加。结论：As2O3诱导食管癌细胞G2/M期阻滞抑制细胞增殖和生长;HSP70的升高是细胞对As2O3作用后出现的应激反应,并与细胞周期阻滞相关。