Anti-inflammatory response after infusion of p55 soluble tumor necrosis factor receptor fusion protein for severe sepsis

OBJECTIVES: To investigate the effects of Lenercept , a recombinant soluble TNF receptor p55 fused to an immunoglobulin heavy chain IgG1, on the balance of pro- and anti-inflammatory mediators in sepsis. DESIGN: Post hoc analysis of a subgroup of patients enrolled in a multicenter phase III, prospective, double-blind, placebo-controlled, randomized study of Lenercept in severe sepsis. SETTING: Surgical and medical intensive care units, and postoperative recovery room of a tertiary care teaching hospital. PATIENTS: A total of 57 patients were enrolled in the multicenter study in our center. Intervention: Septic patients were randomly assigned to receive either Lenercept 0.125 mg/kg or placebo. The patients were followed for up to 28 days after randomization. MEASUREMENTS AND MAIN RESULTS: Circulating levels of TNF-alpha, IL-6, TNFsR75 and IL-1Ra were measured before and after treatment. The two groups were comparable with regard to age, gender and diagnosis distribution. The total level of TNF-alpha increased significantly in treated patients, compared to patients receiving placebo. The levels of the other inflammatory mediators did not differ between the two groups CONCLUSIONS: Lenercept -treated patients experienced a protracted TNF-alpha half-life, leading to higher total TNF-alpha levels throughout the study. However, the treatment had no effects on anti-inflammatory mediators. Therefore, peripheral inflammatory processes might not have been significantly modified by the treatment. This might account for the lack of efficacy this treatment in septic patients     

Polarisation of prokaryotic chromosomes

In many prokaryotes, asymmetrical mutational or selective pressures have caused compositional skews between complementary strands of replication arms, especially sensitive in the distribution of guanine and cytosine. In Escherichia coli, most of the guanine/cytosine skew is caused by mutation rates differing on leading and lagging strands, but contribution of skewed functionally important guanine-rich motifs (Chi and Rag sites), which control chromosome repair or positioning, is noticeable. Interference between replication and gene expression plays a minor role. The situation may be different in other bacteria. Studies of chromosome processing and bacterial taxonomy might profit from consideration of chromosome polarisation.     

A simple and convenient microtiter plate assay for the detection of bactericidal antibodies to Vibrio cholerae O1 and Vibrio cholerae O139

It is believed that the correlate of protection for cholera can be determined by the serum vibriocidal assay. The currently available vibriocidal assays, based on the conventional agar plating technique, are labor intensive. We developed a simple and convenient microtiter plate assay for the detection of vibriocidal antibodies that is equally as efficient for Vibrio cholerae O1 and for V. cholerae O139. The addition of succinate and neotetrazolium made it possible to measure the growth of surviving bacterial target cells by monitoring a color change. We evaluated assay parameters (target strains, growth of target cells, complement source and concentration) that may affect the reproducibility of the method for V. cholerae O139. The results obtained with the microtiter plate assay were uniformly similar to those obtained with the conventional agar plating assay, when testing both the Inaba and Ogawa serotypes of V. cholerae O1. The microtiter plate assay was also convenient for measuring the activity of animal sera and mouse monoclonal antibodies.     

Distribution of the species of the Anopheles gambiae complex and first evidence of Anopheles merus as a malaria vector in Madagascar

BACKGROUND: Members of the Anopheles gambiae complex are amongst the best malaria vectors in the world, but their vectorial capacities vary between species and populations. A large-scale sampling of An. gambiae sensu lato was carried out in various bioclimatic domains of Madagascar. Local abundance of an unexpected member of this complex raised questions regarding its role in malaria transmission. METHODS: Sampling took place at 38 sites and 2,067 females were collected. Species assessment was performed using a PCR targeting a sequence in the IGS of the rDNA. Analysis focused on the relative prevalence of the species per site, bioclimatic domain and altitude. Infectivity of Anopheles merus was assessed using an ELISA to detect the presence of malarial circumsporozoite protein in the head-thorax. RESULTS: Three species were identified: An. gambiae, Anopheles arabiensis and An. merus. The distribution of each species is mainly a function of bioclimatic domains and, to a lesser extent, altitude. An. arabiensis is present in all bioclimatic domains with highest prevalence in sub-humid, dry and sub-arid domains. An. gambiae has its highest prevalence in the humid domain, is in the minority in dry areas, rare in sub-humid and absent in sub-arid domains. An. merus is restricted to the coastal fringe in the south and west; it was in the majority in one southern village. The majority of sites were sympatric for at least two of the species (21/38) and two sites harboured all three species.The role of An. merus as malaria vector was confirmed in the case of two human-biting females, which were ELISA-positive for Plasmodium falciparum. CONCLUSION: Despite the huge environmental (mainly man-made) changes in Madagascar, the distribution of An. gambiae and An. arabiensis appears unchanged for the past 35 years. The distribution of An. merus is wider than was previously known, and its effectiveness as a malaria vector has been shown for the first time; this species is now on the list of Malagasy malaria vectors.     

Diatom cultivation and biotechnologically relevant products. Part I: Cultivation at various scales

Biotechnological applications of diatoms are still in development. Further development at the industrial scale will depend on optimisation of the culture process with the aim of reducing costs. Because of the photoautotrophic status of the majority of diatoms, microalgal cultures suffer from the limitation of light diffusion, which requires the development of suitable photobioreactors. Thus, genetically engineered microalgae that may be cultivated in heterotrophic conditions present a new opportunity. Other limiting factors, such as nutrients (phosphate, nitrogen, silicon), pH, temperature, bioturbation and many more must be taken into account. Most of the time, metabolic stress conditions lead to an overproduction of the products of interest, with a decrease in biomass production as a consequence. Outdoor cultures in open ponds are usually devoted to aquaculture for the feeding of shrimps and bivalve molluscs (commercial production), while closed axenic indoor/outdoor photobioreactors are used for biotechnological compounds of homogeneous composition (still at the laboratory scale). In addition to the optimum culture conditions that have to be taken into account for photobioreactor design, the localisation of produced metabolites (intra- or extracellular) may also be taken into account when choosing the design. Microalgal cell immobilisation may be a suitable technique for application to benthic diatoms, which are usually sensitive to bioturbation and/or metabolites which may be overexpressed.     

Various synaptic activities and firing patterns in cortico-striatal and striatal neurons in vivo

It is commonly assumed that spontaneous activity of striatal output neurons is characterized by a two-state behavior. This assumption is mainly based on in vivo intracellular recordings under urethane and/or ketamine-xylazine anesthesia showing that striatal neurons oscillate between two preferred membrane potentials, a Down state (hyperpolarized level), resulting from an inwardly rectifying potassium conductance, and an Up state (depolarized level) caused by complex interactions between a barrage of cortical synaptic excitation and voltage-dependent potassium conductances. However, a recent comparative study using different anesthetics showed that striatal neurons can exhibit various shapes of synaptic activity depending on the temporal structure and the degree of synchronization of their cortico-striatal afferents. These new data demonstrate that the "classical" Up and Down states do not provide the unique spontaneous activity that can be encountered in striatal neurons in vivo. Rather we propose that striatal neurons should exhibit various synaptic activities and firing patterns depending on the states of vigilance. This hypothesis would be validated in further experiments in which the intracellular activity of striatal neurons will be recorded during the natural sleep-wake cycle.     

A Technique To Quantify the Population Size and Composition of the Biofilm Component in Communities of Bacteria in the Phyllosphere

The presence of microbial biofilms in the phyllosphere of terrestrial plants has recently been demonstrated, but few techniques to study biofilms associated with living plant tissues are available. Here we report a technique to estimate the proportion of the bacterial population on leaves that is assembled in biofilms and to quantitatively isolate bacteria from the biofilm and nonbiofilm (solitary) components of phyllosphere microbial communities. This technique is based on removal of bacteria from leaves by gentle washing, separation of biofilm and solitary bacteria by filtration, and disintegration of biofilms by ultrasonication. The filters used for this technique were evaluated for their nonspecific retention rates of solitary bacteria and for the efficiency of filtration for different concentrations of solitary bacteria in the presence of biofilms and other particles. The lethality and efficiency of disintegration of the sonication conditions used here were also evaluated. Isolation and quantification of bacteria by this technique is based on use of culture media. However, oligonucleotide probes, sera, or epifluorescent stains could also be used for direct characterization of the biofilm and solitary bacteria in the suspensions generated by this technique. Preliminary results from estimates of biofilm abundance in phyllosphere communities show that bacteria in biofilms constitute between about 10 and 40% of the total bacterial population on broad-leaf endive and parsley leaves.     

Ndd, the Bacteriophage T4 Protein That Disrupts the Escherichia coli Nucleoid, Has a DNA Binding Activity

Early in a bacteriophage T4 infection, the phage ndd gene causes the rapid destruction of the structure of the Escherichia coli nucleoid. Even at very low levels, the Ndd protein is extremely toxic to cells. In uninfected E. coli, overexpression of the cloned ndd gene induces disruption of the nucleoid that is indistinguishable from that observed after T4 infection. A preliminary characterization of this protein indicates that it has a double-stranded DNA binding activity with a preference for bacterial DNA rather than phage T4 DNA. The targets of Ndd action may be the chromosomal sequences that determine the structure of the nucleoid.     

The effect of parasitism by Aphelinus abdominalis and drought on the walking movement of aphids

The effect of simulated plant stress and parasitism by Aphelinus abdominalis (Dalman) on the mobility of four species of aphids was investigated. The aphids were placed on water stressed potted plants or on excised leaf segments on dry or moist filter-paper in Petri dishes. Winter wheat (Triticum aestivum) was infested with Metopolophium dirhodum (Walker), Sitobion avenae (F.) and Rhopalosiphum padi (L.) (segments only), aubergine (Solanum melongena) leaf segments with Macrosiphum euphorbiae (Thomas). The aphids that moved off the plants were removed and their development stage determined at 24-h (drought-stressed plants) or 3-h (leaf segments) intervals. On intact plants, aphid larvae were reluctant to move, and only moved after moulting into adults. On cut leaves, young 1st and 2nd instar larvae were more reluctant to move than 3rd and 4th instar larvae and adults. The numbers moving were initially positively correlated with aphid population density, and in M. euphorbiae occurred mainly during the night. Depending on aphid species and parasitoid age, parasitism by A. abdominalis retarded or accelerated movement, but the differences between young and old larvae and adults persisted after parasitism. A. abdominalis lays male eggs in small hosts and female eggs in large hosts. Consequently, its sex ratio was affected by differential movement of the host aphids of the male and female parasitoids. Old larvae and adult aphids readily moved and carried off female parasitoids, while the small aphids were more likely to remain and give rise to male-biased sex ratios.