Preliminary x-ray investigation of an orthorhombic crystal form of human plasma albumin.

An orthorhombic form of single crystals of human plasma albumin, suitable for x-ray diffraction studies, has been grown with ammonium sulfate from protein solutions purified from fresh frozen single donor plasma as well as from a commercial sample of plasma albumin. The space group is P2(1)2(1)2 with 12 molecules in the unit cell. The cell dimensions are: a = 133.3 +/- 1.2 A, b = 274.8 +/- 3.3 A,, and c = 58.02 +/- 0.02 A.     

Circulation of Campylobacter spp. in rhesus monkeys (Macaca mulatta) held in captivity: a longitudinal study

Campylobacteriosis is an extremely important zoonosis, circulating freely in the environment. In nonhuman primates kept in open facilities and bred for experimental purposes, the presence of Campylobacter spp. could cause severe damage to the production and interfere with the results of scientific research. In this paper, we assessed the circulation of Campylobacter spp. in a colony of clinically healthy rhesus monkeys (Macaca mulatta) destined to research. The analysis was carried out during seven non-consecutive years. Data showed that despite several changes made in animal management along the studied years in order to control this zoonosis, reduction of bacterial charge did not occur. Significant differences among the age groups and sex were observed. Infants showed higher susceptibility than adult animals. In general males were more infected than females. Modifications adopted in the handling techniques need to be reviewed with the intent of improving the production, reducing bacterial infection of the stock and avoiding undesirable cross reactions in the research carried out with these animals. Therefore, this paper alerts professionals that work directly with captive rhesus monkeys about the risks of Campylobacter spp. infection and possible interference on the experimental procedures.     

The RNA-binding protein hnRNPLL induces a T cell alternative splicing program delineated by differential intron retention in polyadenylated RNA

Background

Retention of a subset of introns in spliced polyadenylated mRNA is emerging as a frequent, unexplained finding from RNA deep sequencing in mammalian cells.

Results

Here we analyze intron retention in T lymphocytes by deep sequencing polyadenylated RNA. We show a developmentally regulated RNA-binding protein, hnRNPLL, induces retention of specific introns by sequencing RNA from T cells with an inactivating Hnrpll mutation and from B lymphocytes that physiologically downregulate Hnrpll during their differentiation. In Ptprc mRNA encoding the tyrosine phosphatase CD45, hnRNPLL induces selective retention of introns flanking exons 4 to 6; these correspond to the cassette exons containing hnRNPLL binding sites that are skipped in cells with normal, but not mutant or low, hnRNPLL. We identify similar patterns of hnRNPLL-induced differential intron retention flanking alternative exons in 14 other genes, representing novel elements of the hnRNPLL-induced splicing program in T cells. Retroviral expression of a normally spliced cDNA for one of these targets, Senp2, partially corrects the survival defect of Hnrpll-mutant T cells. We find that integrating a number of computational methods to detect genes with differentially retained introns provides a strategy to enrich for alternatively spliced exons in mammalian RNA-seq data, when complemented by RNA-seq analysis of purified cells with experimentally perturbed RNA-binding proteins.

Conclusions

Our findings demonstrate that intron retention in mRNA is induced by specific RNA-binding proteins and suggest a biological significance for this process in marking exons that are poised for alternative splicing.     

Scale-Up,Retention and HIV/STI Prevalence Trends among Female Sex Workers Attending VICITS Clinics in Guatemala

Background

Since 2007, Guatemala integrated STI clinical service with an HIV prevention model into four existing public health clinics to prevent HIV infection, known as the VICITS strategy. We present the first assessment of VICITS scale-up, retention, HIV and STI prevalence trends, and risk factors associated with HIV infection among Female Sex Workers (FSW) attending VICITS clinics in Guatemala.

Methods

Demographic, behavioral and clinical data were collected using a standardized form. Data was analyzed by year and health center. HIV and STI prevalence were estimated from routine visits. Retention was estimated as the percent of new users attending VICITS clinics who returned for at least one follow-up visit to any VICITS clinic within 12 months. Separate multivariate logistic regression models were conducted to investigate factors associated with HIV infection and program retention.

Results

During 2007–2011 5,682 FSW visited a VICITS clinic for the first-time. HIV prevalence varied from 0.4% to 5.8%, and chlamydia prevalence from 0% to 14.3%, across sites. Attending the Puerto Barrios clinic, having a current syphilis infection, working primarily on the street, and using the telephone or internet to contact clients were associated with HIV infection. The number of FSW accessing VICITS annually increased from 556 to 2,557 (361%) during the period. In 2011 retention varied across locations from 7.7% to 42.7%. Factors negatively impacting retention included current HIV diagnosis, having practiced sex work in another country, being born in Honduras, and attending Marco Antonio Foundation or Quetzaltenango clinic sites. Systematic time trends did not emerge, however 2008 and 2010 were characterized by reduced retention.

Conclusions

Our data show local differences in HIV prevalence and clinic attendance that can be used to prioritize prevention activities targeting FSW in Guatemala. VICITS achieved rapid scale-up; however, a better understanding of the causes of low return rates is urgently needed.     

Engineering of ethanolic E. coli with the Vitreoscilla hemoglobin gene enhances ethanol production from both glucose and xylose

Escherichia coli strain FBR5, which has been engineered to direct fermentation of sugars to ethanol, was further engineered, using three different constructs, to contain and express the Vitreoscilla hemoglobin gene (vgb). The three resulting strains expressed Vitreoscilla hemoglobin (VHb) at various levels, and the production of ethanol was inversely proportional to the VHb level. High levels of VHb were correlated with an inhibition of ethanol production; however, the strain (TS3) with the lowest VHb expression (approximately the normal induced level in Vitreoscilla) produced, under microaerobic conditions in shake flasks, more ethanol than the parental strain (FBR5) with glucose, xylose, or corn stover hydrolysate as the predominant carbon source. Ethanol production was dependent on growth conditions, but increases were as high as 30%, 119%, and 59% for glucose, xylose, and corn stover hydrolysate, respectively. Only in the case of glucose, however, was the theoretical yield of ethanol by TS3 greater than that achieved by others with FBR5 grown under more closely controlled conditions. TS3 had no advantage over FBR5 regarding ethanol production from arabinose. In 2 L fermentors, TS3 produced about 10% and 15% more ethanol than FBR5 for growth on glucose and xylose, respectively. The results suggest that engineering of microorganisms with vgb/VHb could be of significant use in enhancing biological production of ethanol.     

Primary Spermatocyte-Specific Cre Recombinase Activity in Transgenic Mice

We have evaluated the specificity of Cre recombinase activity in transgenic mice expressing Cre under the control of the synatonemal complex protein 1 (Sycp1) gene promoter. Sycp1Cre mice were crossed with the ROSA26 reporter line R26R, to monitor the male germ cell stage-specificity of Cre activity as well as to verify that Cre was not active previously during development of other tissues. X-gal staining detected Cre-mediated recombination only in testis. Detailed histological examination indicated that weak Cre-mediated recombination occurred as early as in zygotene spermatocytes at stage XI of the cycle of the seminiferous epithelium. Robust expression of X-gal was detected in early to mid-late spermatocytes at stages V-VIII. We conclude that this transgenic line is a powerful tool for deleting genes of interest specifically during male meiosis.