A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Production of DON-related trichothecenes byFusarium graminearum Schw from Krasnodarski krai of the USSR

34Fusarium graminearum Schw isolates produced 4-deoxynivalenol to form significant amounts of 4, 7 — dideoxynivalenol and lesser amounts of 4 — deoxynivalenol monoacetates on grain substratesin vitro. This is the first report on the capability a large group of naturally occurring isolates to produce 4,7-dideoxynivalenol. The average levels of 4,7-dideoxynivalenol on rice, corn, barley, and wheat as a substrate were respectively 26.8, 14.0, 12.8, and 10.5% of the level of 4-deoxynivalenol. 4, 7 — dideoxynivalenol was present in all examined naturally contaminated wheat kernel samples at levels of 1.7 to 7.9% of the level of 4-deoxynivalenol. These findings suggest that more attention should be given to the occurrence of 4,7-dideoxynivalenol in cereals.     

Damage to the chloroplast H+-ATPase complex by low concentrations of glutaraldehyde

The energy-dependent processes coupled to electron transport were studied in isolated pea chloroplasts treated with low concentrations (1-5 mM) of glutaraldehyde (GA) in the dark and in the light sufficient to cause energization of the membrane. After GA treatment the chloroplasts exhibited a strong suppression of cyclic and non-cyclic phosphorylation, coupled (+ADP+Pi) electron transport and diminution of the light-activated Mg2+-ATPase activity. The rate of basal electron transport was unaffected. The GA-treated chloroplasts were found to retain the capacity to form the osmotic component of the transmembrane potential. These data and the results of the effect of florizine and ATP on electron transport suggest that the effect of GA on energy transduction processes associated with photophosphorylation may consist in its action on reversible H+-ATPase. In light-adapted samples treated with GA the data characterizing the formation of a high energy state (rate of photophosphorylation, steady-state level of photo-induced quenching of atebrin fluorescence and its dark recovery; photo-induced absorbance changes at 520 nm; rate of the slow phase of delayed fluorescence increment) appear to be changed to a greater extent as compared to the dark-adapted samples. The observed changes may arise from a greater conductivity of thylakoid membranes due to fixation of the H+-ATPase proton channel in the "open" state.     

The Mechanisms and Role of Photosynthetic Hydrogen Production by Green Microalgae

Microbiology - The review clarifies the mechanisms of H2 production by green microalgae and the physiological role of the [FeFe] hydrogenase in adaptation of these organisms to varying...     

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.     

Chlorophyll fluorescence induction and relaxation system for the continuous monitoring of photosynthetic capacity in photobioreactors

The development of high‐performance photobioreactors equipped with automatic systems for non‐invasive real‐time monitoring of cultivation conditions and photosynthetic parameters is a challenge in algae biotechnology. Therefore, we developed a chlorophyll (Chl) fluorescence measuring system for the online recording of the light‐induced fluorescence rise and the dark relaxation of the flash‐induced fluorescence yield (Qa^? ? re‐oxidation kinetics) in photobioreactors. This system provides automatic measurements in a broad range of Chl concentrations at high frequency of gas‐tight sampling, and advanced data analysis. The performance of this new technique was tested on the green microalgae Chlamydomonas reinhardtii subjected to a sulfur deficiency stress and to long‐term dark anaerobic conditions. More than thousand fluorescence kinetic curves were recorded and analyzed during aerobic and anaerobic stages of incubation. Lifetime and amplitude values of kinetic components were determined, and their dynamics plotted on heatmaps. Out of these data, stress‐sensitive kinetic parameters were specified. This implemented apparatus can therefore be useful for the continuous real‐time monitoring of algal photosynthesis in photobioreactors.     

Effect of methylmercury on primary photosynthesis processes in green microalgae Chlamydomonas reinhardtii

The sensitivity of green microalgae Chlamydomonas reinhardtii to methylmercury chloride (MeHg) and chloride mercury (HgCl2) was evaluated by measuring chlorophyll fluorescence parameters by the pulse-amplitude-modulation (PAM) fluorometry. It was shown that MeHg at concentrations above 1 microM decreased the Fv/Fm ratio, which characterizes the maximal efficiency of energy utilization in photosystem II. The degree of inhibition depended on the time of treatment and was always higher under illumination conditions (50 microE.m-2.s-1) than under dark conditions. A similar regularity was observed for the delta F/Fm' ratio, which characterizes the real efficiency of energy storage at the given intensity of the photosynthesis-exciting light. Incubation with 5 microM HgCl2 for 5 h did not affect both ratios. The decrease in Fm at constant F0 as well as changes in the fast fluorescence kinetics after MeHg treatment of algae cells indicated the damage on the donor side of photosystem II and the damage of the electron transfer from QA to QB. The reduction of photochemical fluorescence quenching (qN) under MeHg treatment is also evidence of the increase in the fraction of closed reaction centers (QA-). At the same time, increase in the steady-state level of P700 photooxidation indicated a disturbance of electron transfer between photosystems. The present study demonstrates that methylmercury treatment damaged the photosynthetic electron transfer chain at several sites. The inhibitory effect of methylmercury is much stronger than the effect of mercury chloride on photosynthetic processes.     

Experimental and theoretical study of processes of cyclical electron transport around photosystem I

The kinetics of photoinduced EPR I signals at different concentrations of ferredoxin was studied on isolated pea chloroplasts. A kinetic model of ferredoxin-dependent electron transport around photosystem I was suggested. A multiparticle model was constructed, which makes it possible to "directly" model the processes of electron transfer in multiprotein complexes and limited diffusion in different compartments of the system (stroma, lumen, and intermembrane space). A comparison of the kinetic and "direct" models revealed an important role of spatial organization of the system in the kinetics of redox turnover of P700.     

Inter-familial relationships of the shorebirds (Aves: Charadriiformes) based on nuclear DNA sequence data

Background  

Phylogenetic hypotheses of higher-level relationships in the order Charadriiformes based on morphological data, partly disagree with those based on DNA-DNA hybridisation data. So far, these relationships have not been tested by analysis of DNA sequence data. Herein we utilize 1692 bp of aligned, nuclear DNA sequences obtained from 23 charadriiform species, representing 15 families. We also test earlier suggestions that bustards and sandgrouses may be nested with the charadriiforms. The data is analysed with methods based on the parsimony and maximum-likelihood criteria.     

Effect of methylmercury chloride on the primary photosynthetic activity of higher plants

The effect of methylmercury chloride (MeHg) on the fluorescence characteristics of pea seedling leaves and thylakoids isolated from these leaves was studied by the pulse-amplitude-modulation (PAM) fluorometric method. In 3-4 days after the addition of MeHg (20 microM) to the nutritious solution, the maximal (Fv/Fm) and real (under steady state actinic light illumination) (deltaF/F'm) quantum photochemical yield of PS II decreased. The nonphotochemical fluorescence quenching coefficient in control (qN) decreased after its maximum value has been reached. In MeHg-treated samples, this decrease was not observed, possibly due to the disturbance of delta pH energy transducing processes in ATP synthase. This was confirmed by the results of experiments on isolated thylakoids. After MeHg (5 microM) treatment of thylakoids, the photophosphorylation rate and light-triggered Mg2+-dependent H+-ATPase activity were suppressed by 20-40%, depending on the duration of MeHg exposure. However, in experiments with isolated thylakoids, no decrease either in the electron transport rate or in the Fv/Fm ratio was observed. In total, the results obtained allow one to assume that MeHg at concentrations and time duration used directly damages the coupling complex. The PS II inactivation in leaves and algae cells may be a result of the oxidative stress processes.