Identification of nucleotide sequences for the specific and rapid detection of Yersinia pestis

Suppression subtractive hybridization, a cost-effective approach for targeting unique DNA, was used to identify a 41.7-kb Yersinia pestis-specific region. One primer pair designed from this region amplified PCR products from natural isolates of Y. pestis and produced no false positives for near neighbors, an important criterion for unambiguous bacterial identification.     

Stable isotope fractionation by Clostridium pasteurianum. 1. 34S/32S: inverse isotope effects during SO4-2- and SO3-2- reduction.

During growth on minimal salts--sucrose media supplemented with various concentrations (10-4-10-2 M) of sodium sulfate, Clostridium pasteurianum grew at a normal rate and only evolved sulfide in late stages of growth on 10-2 M SO4-2-. The evolved sulfide was slightly enriched in 34S as compared to the medium sulfur. On the other hand, sulfide was evolved during growth on all concentrations of sulfite tested. Large normal and inverse isotopic effects were observed in the evolved sulfide during SO3-2- reductions. In contrast, the intracellular sulfur showed much smaller fractionations. The complexity of the isotopic patterns suggests that a dissimilatory sulfite reductase system may be induced by high concentrations of sulfite.     

Heterogeneity of Intermediate Filament Expression in Vascular Smooth Muscle: A Gradient in Desmin Positive Cells from the Rat Aortic Arch to the Level of the Arteria Iliaca Communis

The display of the two distinct intermediate filament proteins, desmin and vimentin, in rat vascular smooth muscle tissue was studied by immunofluorescence microscopy on frozen sections of aorta and other blood vessels. Vascular smooth muscle cells present in these vessels always appeared rich in vimentin. However, staining of sections covering six distinct but contiguous parts of the aorta showed that the number of desmin containing cells was low distal to the truncus brachiocephalicus, but increases until in distal parts of the aorta and in the arteria iliaca communis almost all cells appear positive for desmin. Thus blood vessels show heterogeneity of intermediate filament expression not only in cross-section but can also display heterogeneity along their length. Muscular arteries such as the renal artery and the arteria femoralis, as well as arterioles and veins including the vena jugularis and the vena cava also contain desmin. Thus it may be that low numbers of desmin-positive cells are typical of elastic arteries, while muscular arteries and other blood vessels are characterized by large numbers of desmin-positive cells. We discuss whether desmin-positive and desmin-negative vascular smooth muscle cells may perform different functions and raise the possibility that desmin expression may coincide with the turn on of a specially regulated contractility program.     

Somatoform disorders among patients attending walk-in clinics in Trinidad: prevalence and association with depression and anxiety

Objectives Somatoform disorders are common in international primary care settings, but have been little studied in the developing world. The objective of this study was to determine the prevalence of severe undifferentiated somatoform disorder, and its relationship to depression and anxiety, among patients attending walk-in clinics in Trinidad.Methods The study participants, who were all aged 18 years or older and attending walk-in clinics at 16 randomly selected health centres, were surveyed between May and August 2007 using the PRIME-MD questionnaire.Results There were 594 participants (the response rate was 92%), of whom 72.7% were female. Their ages ranged from 18 to 93 years, and 54.5% were over 50 years of age. In total, 37.2% were married and 25.9% were single. Indo-Trinidadians represented 43.1% and Afro-Trinidadians represented 36% of the study sample; 56.5% of the participants reported that their income was less than US$ 400 per month, and 65.7% were unemployed. At walk-in clinics in Trinidad, the estimated prevalence of severe undifferentiated somatoform disorder was 10.3% (95% CI: 7.86–12.74), that of hypochondriasis was 28.5% (95% CI: 24.9–32.1), and that of body dysmorphic disorder was 15.8% (95% CI: 11.9–18.7). Severe undifferentiated somatoform disorder was statistically significantly associated with gender and ethnicity but not with age, level of education, employment status or income. Chi-square testing found significant associations between the presence of severe undifferentiated somatoform disorder and both depression and anxiety (P < 0.05), between hypochondriasis and both anxiety and depression (P < 0.05), and between body dysmorphic disorder and depression (P < 0.05) but not anxiety. Regression analysis suggested that the demographic features that predicted severe undifferentiated somatoform disorder were being female or Indo-Trinidadian.Conclusions Walk-in clinics in Trinidad that serve older patients on a lower income have a high proportion of patients with somatoform disorders as measured by the PRIME-MD scale. These patients exhibit many features of anxiety and depression. These findings have implications for medical training and service delivery.     

Sulfur Isotope Fractionation and Kinetic Studies of Sulfite Reduction in Growing Cells of Salmonella heidelberg

A pulsed feeding technique was used during studies of sulfite reduction by Salmonella heidelberg in order to realize large percentages of SO₃⁼ conversion while simultaneously maintaining a reasonably stable cell population. As a consequence, much data for conventional kinetic and sulfur isotope fractionation computations were obtained in any one experiment. Under the conditions of supplying 150 μg glucose per ml of medium every 6 hr, anaerobiosis, and varying the SO₃⁼ concentration, the following observations were made: 1. Below 0.01% w/v Na₂SO₃, the reduction strictly followed first order kinetics with respect to SO₃⁼ concentration. At higher concentrations, the rate of SO₃⁼ reduction fell below that predicted by first order kinetics suggesting that a saturation effect was occurring. 2. At lower concentrations, the ratio of the isotopic rate constants k₁/k₂ was 1.02 whereas at higher SO₃⁼ levels, k₁/k₂ values of 1.04 were found. These latter effects are much higher than those obtained in the equivalent chemical reduction. On the basis of these observations, a model is considered which features two isotopically dependent steps and an intermediate reservoir which forms at higher SO₃⁼ concentrations. Results of an experiment under aerobic conditions and an experiment wherein the reduction rate was thermally altered, are also presented.     

Water permeability of plant cuticular membranes: the effects of humidity and temperature on the permeability of non-isolated cuticles of onion bulb scales

Abstract. Water permeability of cuticular membranes (CM) from the inner bulb scales of Allium cepa has been investigated. CM have a thickness ranging from 0.6 to 1.3 μm. They are composed of a thin (120–200 nm) lamellated cuticle proper and a thicker (300–900 nm) cuticular layer. Permeability coefficients for diffusion of water across these thin membranes are very low (4 × lO⁻¹⁰ms⁻¹⁰). There was no difference in permeability of CM from successive scales of the same onion. Extraction of soluble cuticular lipids (SCL) with chloroform increased permeability by a factor of 1350 to 2050. Preliminary data indicate that only 1 μg cm⁻¹⁰ of SCL are removed by this treatment, hydrocarbons being the main (75%) consistuent. Permeability coefficients of cuticular transpiration were little affected by relative humidity, showing that transport is limited by a hydrophobic barrier that lacks dipoles. However, following extraction, permeability of the membranes depended strongly on humidity due to the presence of polar functional groups in the polymer matrix. Soluble cuticular lipids undergo a phase transition around 47°C. Temperatures higher than that irreversibly increased water permeability.