Nitrogen concentrations in a mangrove creek with a large tidal range,Peninsular Malaysia

We report on various species of nitrogen in subsurface water samples taken at the mouth of Sungai Sementa Besar, a creek about 4.5 km long off the Straits of Malacca and draining a mangrove forest on the west coast of Peninsular Malaysia. This tide-dominated watercourse shows a range greater than 4.5 metres from low to high water during springs, only 1.0 m during neaps, and salinities at the mouth of 30 or greater. After heavy rains or when the tides inundate the forest floor, inorganic nitrogen values increase as much as tenfold at the mouth. Particulate and total organic nitrogen also increase at the mouth under these conditions. There were also comparative highs of organic inputs at other times.     

Clinical significance of a high mean corpuscular volume in nonanemic patients.

A prospective study of the clinical significance of macrocytosis (mean corpuscular volume 100 fL or more) was carried out for 9 months in a teaching hospital in 1975. Of the 140 patients with macrocytosis at the time of admission (0l7% of all hospital admissions) 46 (33%) had low activity of serum or erythrocyte folate, or both, and 16 (11%) had low serum vitamin B12 concentrations. Among the 78 patients with normal B12 and folate values the most commonly associated significant clinical conditions were alcoholism or hepatic disease (36 patients), malignant disease or the effects of chemotherapy (25 patients) and chronic obstructive lung disease (10 patients).     

Conformational disturbance induced by AzPro/Pro substitution in peptides

Consequences inherent to the substitution ofaza-proline (AzPro) for proline in the octapeptideTTSAPTTS, representative of the tandem repeat motifpresent in the peptide backbone of MUC5AC mucin, wereanalysed in terms of conformational perturbation andO-glycosylation aptitude. In DMSO solution, weobserved the same tendency previously noted inAzPro-tripeptide models, i.e. AzPro prevents-turn formation in which it would occupy thei+1 position, and therefore behaves quite oppositeto Pro, whereas both AzPro and Pro can support a-turn in the i+2 position with a cisdisposition of the preceding tertiary amide function.The former structural modifications do not preventO-glycosylation to take place at the same specificsite, but it occurs at a reduced rate.     

Conformational and antigenic properties of SRYD-containing peptide analogues of Leishmania gp63 adhesion site

Summary The antigenicity and conformational properties of the Ser-Arg-Tyr-Asp (SRYD) segment (252–255) of the major surface glycoprotein ofLeishmania, gp63, which plays a key role in the parasite-macrophage attachement, are presented. It was found that the antibody recognition, using anti-IASRYDQL antibodies, of the SRYD-containing analogues, Ac-SRYD-NH₂ (1), ANIASRYD-NH₂ (2), Ac-SRYD (3), SRYD (4) and ANIASRYD (5), is rather similar. The structure of the SRYD moiety in analogues 1 and 2 is characterized by the presence of a type I -turn, stabilized by the formation of a hydrogen bonding between the C-terminaltrans-carboxamide proton and the Arg-CO and an ionic bridge between arginine and aspartic acid side chains, while the conformation of compounds 3, 4 and 5 is stabilized by an ionic bridge between the arginine side chain and the C-terminal carboxylate group. A common structural motif involving the arginine side chain in an ionic interaction is identified in all the SRYD analogues, which may explain the observed similarities in the antibody recognition of the reported peptides.     

Azithromycin and Ciprofloxacin Resistance in Salmonella Bloodstream Infections in Cambodian Adults

Background

Salmonella enterica is a frequent cause of bloodstream infection (BSI) in Asia but few data are available from Cambodia. We describe Salmonella BSI isolates recovered from patients presenting at Sihanouk Hospital Centre of Hope, Phnom Penh, Cambodia (July 2007–December 2010).

Methodology

Blood was cultured as part of a microbiological prospective surveillance study. Identification of Salmonella isolates was performed by conventional methods and serotyping. Antibiotic susceptibilities were assessed using disk diffusion, MicroScan and E-test macromethod. Clonal relationships were assessed by Pulsed Field Gel Electrophoresis; PCR and sequencing for detection of mutations in Gyrase and Topoisomerase IV and presence of qnr genes.

Principal Findings

Seventy-two Salmonella isolates grew from 58 patients (mean age 34.2 years, range 8–71). Twenty isolates were identified as Salmonella Typhi, 2 as Salmonella Paratyphi A, 37 as Salmonella Choleraesuis and 13 as other non-typhoid Salmonella spp. Infection with human immunodeficiency virus (HIV) was present in 21 of 24 (87.5%) patients with S. Choleraesuis BSI. Five patients (8.7%) had at least one recurrent infection, all with S. Choleraesuis; five patients died. Overall, multi drug resistance (i.e., co-resistance to ampicillin, sulphamethoxazole-trimethoprim and chloramphenicol) was high (42/59 isolates, 71.2%). S. Typhi displayed high rates of decreased ciprofloxacin susceptibility (18/20 isolates, 90.0%), while azithromycin resistance was very common in S. Choleraesuis (17/24 isolates, 70.8%). Two S. Choleraesuis isolates were extended spectrum beta-lactamase producer.

Conclusions and Significance

Resistance rates in Salmonella spp. in Cambodia are alarming, in particular for azithromycin and ciprofloxacin. This warrants nationwide surveillance and revision of treatment guidelines.     

A solid-phase synthesis of three aza-, iminoaza- and reduced aza-peptides from the same precursor

Using the Boc-strategy, a step-by-step synthesis on the PAM solid supportof three aza-, iminoaza- and reduced aza-peptide homologues is described.From the same hydrazinocarbonyl peptide-PAM precursor, the coupling ofeither a Boc-amino acid or a Boc-amino aldehyde gives rise to an aza-peptideor an iminoaza-peptide containing theC-CO-NH-N-CO-NH-C orC-CH=N-N-CO-NH-C surrogate of the peptide motif, respectively. In situreduction of the latter by NaBH₃CN leads to a reducedaza-peptide containing theC-CH₂-NH-N-CO-NH-C moiety. The key step synthesis of thehydrazinocarbonyl peptide-PAM precursor is carried out by coupling on thegrowing peptide chain the N-Boc-aza-amino acid chloride obtained by theaction of triphosgene on the corresponding N-Boc-hydrazine. Thesemodifications have been introduced in position 1-2 of the YLGYLEQLLRbenzodiazepine-like decapeptide     

Phylogeny and divergence of the pinnipeds (Carnivora: Mammalia) assessed using a multigene dataset

Background  

Phylogenetic comparative methods are often improved by complete phylogenies with meaningful branch lengths (e.g., divergence dates). This study presents a dated molecular supertree for all 34 world pinniped species derived from a weighted matrix representation with parsimony (MRP) supertree analysis of 50 gene trees, each determined under a maximum likelihood (ML) framework. Divergence times were determined by mapping the same sequence data (plus two additional genes) on to the supertree topology and calibrating the ML branch lengths against a range of fossil calibrations. We assessed the sensitivity of our supertree topology in two ways: 1) a second supertree with all mtDNA genes combined into a single source tree, and 2) likelihood-based supermatrix analyses. Divergence dates were also calculated using a Bayesian relaxed molecular clock with rate autocorrelation to test the sensitivity of our supertree results further.     

Amino acid requirement of growing pigs depending on amino acid efficiency and level of protein deposition. 2nd communication: threonine

Forty Swiss Large White pigs (barrows with 31.7 kg initial to 103.7 kg final BW) were equally and randomly assigned to one of four treatments (H0, H200, L0, L200) involving a combination of chromium supplementation (0 or 200 μg/kg) and glycemic index (high GI (H) or low GI (L)). Growth performance, energy and protein digestibility, carcass composition, and some plasma traits were investigated.

The data indicated, that the substitution of dietary carbohydrates with fat and crude fibre (low GI) resulted in lower growth performance due to impaired energy digestibility. Moreover, the strong stimulation of insulin secretion due to the high and rapid availability of carbohydrates of the diets HO and H200 caused increased carcass fat deposition. Chromium supplementation also affected plasma insulin and glucagon concentrations. Depending on glycemic index, chromium affected the growth performance. Daily gain was reduced in pigs of the L200 treatment compared to the L0 group. This finding indicated that the energy availability expressed as GI is one of several nutritional factors, which determine the efficacy of dietary chromium. We could not corroborate evidences that dietary chromium modifies the chemical composition of the whole carcass, but depending on GI, chemical composition of the longissimus muscle was affected.