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     

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.     

Composition and nutritive value of some grasses, plants and aquatic weeds tested as diets

The composition and nutritive value of different diets, namely the aquatic weeds— Hydrilla verticillata (L.f.) Presl., Lemna gibbs (L.) Pistia stratiotes (L.), grasses—Guinea grass Panicum maximum Jacq., Napier grass Pennisetum purpureum Schum. and plants—sweet potato leaves Ipomaea batatas L. and tapioca leaves Manihot utilissimus Pohl. were determined and compared. The diets contained 13.5 to 30.48% protein; 1.89 to 9.60% fat; 3.94 to 23.13% ash; 5.42 to 26.70% fibre and 24.87 to 46.27% carbohydrate. Most of the minerals determined in the aquatic weeds were higher than those in grasses and plants. The feeding of Hydrilla , Napier grass and tapioca leaves to grass carp Ctenopharyngodon ideltus (V.) showed a different growth rate and the results obtained indicated the superiority of Hydrilla diet over Napier grass and tapioca leaves.     

A new species of Rhinolophus (Chiroptera: Rhinolophidae) from China

A new species of the genus Rhinolophus is described from Yunnan Province, southwestern China. The new taxon belongs to the Rhinolophus "philippinensis-group" and is distinguished by differences in the nose-leaf structures, craniodental characteristics, and bacular features.     

TLM-Converter: reorganization of long time-lapse microscopy datasets for downstream image analysis

Automated microscopy enables in vivo studies in developmental biology over long periods of time. Time-lapse recordings in three or more dimensions to study the dynamics of developmental processes can produce huge data sets that extend into the terabyte range. However, depending on the available computational resources and software design, downstream processing of very large image data sets can become highly inefficient, if not impossible. To address the lack of available open source and commercial software tools to efficiently reorganize time-lapse data on a desktop computer with limited system resources, we developed TLM-Converter. The software either fragments oversized files or concatenates multiple files representing single time frames and saves the output files in open standard formats. Our application is undemanding on system resources as it does not require the whole data set to be loaded into the system memory. We tested our tool on time-lapse data sets of live Drosophila specimens recorded by laser scanning confocal microscopy. Image data reorganization dramatically enhances the productivity of time-lapse data processing and allows the use of downstream image analysis software that is unable to handle large data sets of ≥2 GB. In addition, saving the outputs in open standard image file formats enables data sharing between independently developed software tools.     

Unexpected X chromosome skewing during culture and reprogramming of human somatic cells can be alleviated by exogenous telomerase

Somatic tissues in female eutherian mammals are mosaic due to random X inactivation. In contrast to mice, X chromosome reactivation does not occur during the reprogramming of human female somatic cells to induced pluripotent stem cells (iPSCs), although this view is contested. Using balanced populations of female Rett patient and control fibroblasts, we confirm that all cells in iPSC colonies contain an inactive X, and additionally find that all colonies made from the same donor fibroblasts contain the same inactive X chromosome. Notably, this extreme "skewing" toward a particular dominant, active X is also a general feature of primary female fibroblasts during proliferation, and the skewing seen in reprogramming and fibroblast culture can be alleviated by overexpression of telomerase. These results have important implications for in?vitro modeling of X-linked diseases and the interpretation of long-term culture studies in cancer and senescence using primary female fibroblast cell lines.     

Development and validation of a simple cell-based fluorescence assay for dipeptidyl peptidase 1 (DPP1) activity

Dipeptidyl peptidase 1 (DPP1) (EC 3.4.14.1; also known as cathepsin C, cathepsin J, dipeptidyl aminopeptidase, and dipeptidyl aminotransferase) is a lysosomal cysteinyl protease of the papain family involved in the intracellular degradation of proteins. Isolated enzyme assays for DPP1 activity using a variety of synthetic substrates such as dipeptide or peptide linked to amino-methyl-coumarin (AMC) or other fluorophores are well established. There is, however, no report of a simple whole-cell-based assay for measuring lysosomal DPP1 activity other than the use of flow cytometry (fluorescence-activated cell sorting) or the use of invasive activity-based probes or the production of physiological products such as neutrophil elastase. The authors investigated a number of DPP1 fluorogenic substrates that have the potential to access the lysosome and enable the measurement of DPP1 enzyme activity in situ. They describe the development and evaluation of a simple noninvasive fluorescence assay for measuring DPP1 activity in fresh or cryopreserved human THP-1 cells using the substrate H-Gly-Phe-AFC (amino-fluoro-coumarin). This cell-based fluorescence assay can be performed in a 96-well plate format and is ideally suited for determining the cell potency of potential DPP1 enzyme inhibitors.     

Amino acid requirement of growing pigs depending on amino acid efficiency and level of protein deposition 1st communication: lysine

In this study we investigated the influence of harvest date and genotype on the ruminai degradability of the organic matter of ensiled maize grains. Grains of the varieties Avenir, Byzance, CGS 5104 and CGS 5107 from six different harvest dates were available; they are classified as intermediate types between flint and dent com. The six harvest dates, during which time the dry matter content of the ensiled grains rose from 52% to 66%, extended from 1st September to 19th October. Assuming a passage rate of k=0.08, the effective ruminai degradability declined in this period on average from 93% to just under 79%; variety‐specific deviations also increased markedly during this period. The dry matter content (x, DM in %) of the ensiled grains had a profound influence on ruminai degradation: a highly significant curvilinear decline in ruminai degradability (y) was calculated at increasing DM levels (k = 0.08), which can be described by the equation y = ?0.072x² (±0.010)+7.417x(±1.186)?98.71(±34.58)(B=0.96;s_y,x[%]=1.36).

The ruminai degradability of ensiled maize grains is about 5–10% higher than that of fresh maize grains.