The X-ray induced G2 arrest in mouse eggs: a maternal effect involving a lack of polypeptide phosphorylation

Summary In some strains of mice, eggs when X irradiated during the pronuclear stage, undergo a mitotic block in the G₂ phase of the first cell cycle and cleave when the second division takes place in controls. The importance of this effect varies considerably with the strain and depends exclusively on the maternal genotype. In previous work, two-dimensional electrophoresis showed that eggs blocked at the one-cell stage after irradiation, undergo the same modifications in polypeptide synthesis as two-cell controls of the same age, except at the time of normal first mitosis, where three polypeptide sets of 30, 35 and 45 kDa appear only in cleaving controls. In the present study, we have found phosphorylations in dividing controls, on polypeptides of 30, 35 and 45 kDa. These phosphorylations are not seen in blocked irradiated eggs.     

Effect of Ethnicity and Geographical Location on Body Weight,Dietary Restraint,and Abnormal Eating Attitudes

Previous studies have examined the effect of ethnicity on obesity, concerns about shape and weight, and attitudes about eating. We hypothesized that geographical location would also influence these variables, and that students growing up in the northern part of the United States and attending northern colleges would differ from students from the South. To examine this, we studied a random sample of 275 African-Americans (AA) and 224 white college students in the entering class of two northern colleges (University of Pittsburgh or University of Massachusetts) or two southern colleges (Augusta or Paine College). All subjects were weighed and completed the Revised Restraint Scale and the EAT-26. AA women were heavier than white women, with no differences due to geographical location. Despite being thinner, white women reported more dietary restraint than AA women. This difference between AA and white women was apparent in both northern and southern college students. In contrast, geographical location was the strongest determinant of bulimic attitudes; both men and women at northern colleges reported higher bulimia scores than those at southern schools. Thus ethnicity appears to be a major determinant of body weight and attitudes about shape and dieting, whereas geographical location appears to exert greater influence on bulimic attitudes.     

Somatostatin inhibition of insulin release from freshly isolated and organ cultured rat islets of langerhans in vitro

1×10^?6M somatostatin causes a 37–44% inhibition of glucose induced insulin release from freshly isolated rat islets of Langerhans. A 81 to 95% inhibition is observed when the isolated islets are maintained in organ culture for 2 days prior to the somatostatin treatment. The dose curve of somatostatin on cultured islets shows an apparent K_I of 1.4×10^?9. The tetradecapeptide also causes a reversible inhibition of the stimulation of insulin release by 5 mM theophylline and 23 mM K⁺.     

Diabetes,metformin use,and colorectal cancer survival in postmenopausal women

Background: Observational studies have associated metformin use with lower colorectal cancer (CRC) incidence but few studies have examined metformin's influence on CRC survival. We examined the relationships among metformin use, diabetes, and survival in postmenopausal women with CRC in the Women's Health Initiative (WHI) clinical trials and observational study. Methods: 2066 postmenopausal women with CRC were followed for a median of 4.1 years, with 589 deaths after CRC diagnosis from all causes and 414 deaths directly attributed to CRC. CRC-specific survival was compared among women with diabetes with metformin use (n = 84); women with diabetes with no metformin use (n = 128); and women without diabetes (n = 1854). Cox proportional hazard models were used to estimate associations among metformin use, diabetes and survival after CRC. Strategies to adjust for potential confounders included: multivariate adjustment with known predictors of colorectal cancer survival and construction of a propensity score for the likelihood of receiving metformin, with model stratification by propensity score quintile. Results: After adjusting for age and stage, CRC specific survival in women with diabetes with metformin use was not significantly different compared to that in women with diabetes with no metformin use (HR 0.75; 95% CI 0.40–1.38, p = 0.67) and to women without diabetes (HR 1.00; 95% CI 0.61–1.66, p = 0.99). Following propensity score adjustment, the HR for CRC-specific survival in women with diabetes with metformin use compared to non-users was 0.78 (95% CI 0.38–1.55, p = 0.47) and for overall survival was 0.86 (95% CI 0.49–1.52; p = 0.60). Conclusions: In postmenopausal women with CRC and DM, no statistically significant difference was seen in CRC specific survival in those who used metformin compared to non-users. Analyses in larger populations of colorectal cancer patients are warranted.     

High Resolution Melting Analysis Targeting hsp70 as a Fast and Efficient Method for the Discrimination of Leishmania Species

Background

Protozoan parasites of the genus Leishmania cause a large spectrum of clinical manifestations known as Leishmaniases. These diseases are increasingly important public health problems in many countries both within and outside endemic regions. Thus, an accurate differential diagnosis is extremely relevant for understanding epidemiological profiles and for the administration of the best therapeutic protocol.

Methods/Principal Findings

Exploring the High Resolution Melting (HRM) dissociation profiles of two amplicons using real time polymerase chain reaction (real-time PCR) targeting heat-shock protein 70 coding gene (hsp70) revealed differences that allowed the discrimination of genomic DNA samples of eight Leishmania species found in the Americas, including Leishmania (Leishmania) infantum chagasi, L. (L.) amazonensis, L. (L.) mexicana, L. (Viannia) lainsoni, L. (V.) braziliensis, L. (V.) guyanensis, L. (V.) naiffi and L. (V.) shawi, and three species found in Eurasia and Africa, including L. (L.) tropica, L. (L.) donovani and L. (L.) major. In addition, we tested DNA samples obtained from standard promastigote culture, naturally infected phlebotomines, experimentally infected mice and clinical human samples to validate the proposed protocol.

Conclusions/Significance

HRM analysis of hsp70 amplicons is a fast and robust strategy that allowed for the detection and discrimination of all Leishmania species responsible for the Leishmaniases in Brazil and Eurasia/Africa with high sensitivity and accuracy. This method could detect less than one parasite per reaction, even in the presence of host DNA.     

Surfactin and fengycin contribute to the protection of a Bacillus subtilis strain against grape downy mildew by both direct effect and defence stimulation

Bacillus subtilis GLB191 (hereafter GLB191) is an efficient biological control agent against the biotrophic oomycete Plasmopara viticola, the causal agent of grapevine downy mildew. In this study, we show that GLB191 supernatant is also highly active against downy mildew and that the activity results from both direct effect against the pathogen and stimulation of the plant defences (induction of defence gene expression and callose production). High-performance thin-layer chromatography analysis revealed the presence of the cyclic lipopeptides fengycin and surfactin in the supernatant. Mutants affected in the production of fengycin and/or surfactin were thus obtained and allowed us to show that both surfactin and fengycin contribute to the double activity of GLB191 supernatant against downy mildew. Altogether, this study suggests that GLB191 supernatant could be used as a new biocontrol product against grapevine downy mildew.     

The cytochrome system of Bacillus megaterium KM. The presence and some properties of two CO-binding cytochromes

1. Difference spectra of Bacillus megaterium KM membrane preparations indicate the presence of two pigments which bind CO and which exhibit the spectral characteristics of cytochromes a₃ and o. Relative amounts of the pigments vary with growth stage of the organism, but both are present at all stages which have been investigated. The pigments are believed to be metabolically active because they are completely reducible by substrate (NADH) and are reoxidizable in the presence of air. CO difference spectra of whole cell suspensions are in agreement with spectra of the isolated membrane fragments. In particulate preparations and in whole cells, CO difference spectra suggest that the a₃ component binds CO much more readily than the o component; this behavior offers a possible explanation for the fact that cytochrome o has been detected in only a few other microorganisms, since CO binding is by definition the property used to identify this cytochrome.

2. A separation of the two CO-binding pigments is obtained by incubation of membrane preparations with pancreatic lipase. This treatment selectively removes the o pigment from the membrane, leaving the a₃ component associated with an enzymatically active particulate fraction.