A plant pathogen reduces the enemy-free space of an insect herbivore on a shared host plant

An important mechanism in stabilizing tightly linked host-parasitoid and prey-predator interactions is the presence of refuges that protect organisms from their natural enemies. However, the presence and quality of refuges can be strongly affected by the environment. We show that infection of the host plant Silene latifolia by its specialist fungal plant pathogen Microbotryum violaceum dramatically alters the enemy-free space of a herbivore, the specialist noctuid seed predator Hadena bicruris, on their shared host plant. The pathogen arrests the development of seed capsules that serve as refuges for the herbivore's offspring against the specialist parasitoid Microplitis tristis, a major source of mortality of H. bicruris in the field. Pathogen infection resulted both in lower host-plant food quality, causing reduced adult emergence, and in twofold higher rates of parasitism of the herbivore. We interpret the strong oviposition preference of H. bicruris for uninfected plants in the field as an adaptive response, positioning offspring on refuge-rich, high-quality hosts. To our knowledge, this is the first demonstration that plant-inhabiting micro-organisms can affect higher trophic interactions through alteration of host refuge quality. We speculate that such interference can potentially destabilize tightly linked multitrophic interactions.     

Methods for a public health response to birth defects clusters

Few resources are available to guide public health officials in investigations of reported birth defects clusters. The majority of published resources focus on the investigation of cancer and infectious disease clusters and do not address clinical and epidemiologic concerns specific to birth defects research. This document aims to address these concerns, discuss the needs of the affected community, and provide suggestions for the development of a standardized protocol to be used as a guide in the investigation of birth defects clusters. We suggest that health departments and birth defects registries that may receive reports of birth defects clusters establish a protocol for responding that includes the following steps: develop a proactive plan for future birth defects cluster reports (step I), receive report of a birth defects cluster (step II), verify diagnoses and complete case ascertainment (step III), compare the observed rate to a reference rate (step IV), ascertain exposures among cases from available records (step V), interview case mothers (step VI), initiate further epidemiologic study-selection of controls (step VII), and communicate results to the community (step VIII). Specific criteria for continuing or terminating an investigation should be established before receiving cluster reports. The recommendations in this report should be carefully considered to ensure that the specific needs of the region, agency and affected community are met.     

Phenotype and regulation of persistent intracerebral T cells in murine Toxoplasma encephalitis

Toxoplasma gondii is a parasite causing asymptomatic, persistent encephalitis. Protective CD4 and CD8 T cells are recruited to and accumulate in the brain in acute Toxoplasma encephalitis (TE), with slowly decreasing numbers in chronic TE. It is unclear how the size of the intracerebral T cell pool is regulated. Conceivably, permanent recruitment, proliferation, and apoptosis may be involved. We observed that in murine TE recruitment of T cells to the brain was terminated in chronic TE. In vivo 5-bromo-2'-deoxyuridine incorporation and in vitro T cell proliferation experiments revealed that intracerebral T cells did not proliferate, which was explained by the expression of the cell cycle inhibitors p21(Waf/cip1) and p27(Kip1) and the inhibitory activity of intracerebral F4/80(+) cells. TUNEL staining detected apoptotic T cells at low frequency corresponding to an increased expression of the anti-apoptotic molecules Bcl-2 and Bcl-x(L) and a reduced expression of the pro-apoptotic molecules Bad, Bax, and Fas ligand in CD4 and CD8 T cells. During progression from acute to chronic TE, both CD4 and CD8 T cells down-regulated CD45RB expression and expressed a differential pattern of cytokines. From these experiments it is concluded that the number of intracerebral T cells increases by recruitment of T cells during acute infection, whereas proliferation of intracerebral T cells does not play a role. In chronic TE, T cell recruitment is terminated, the phenotype of intracerebral T cells changes, and their number is gradually downsized by low level apoptosis, which, however, does not completely resolve the T cell infiltrates.     

Functional significance of a highly conserved glutamate residue of the human noradrenaline transporter

The aim of the study was to investigate the role of glutamate residue 113 in transmembrane domain 2 of the human noradrenaline transporter in determining cell surface expression and functional activity. This residue is absolutely conserved in all members of the Na+- and Cl--dependent transporter family. Mutations to alanine (hE113A), aspartate (hE113D) and glutamine (hE113Q) were achieved by site-directed mutagenesis and the mutants were expressed in transfected COS-7 or HEK-293 cells. Cell surface expression of hE113A and hE113D, but not hE113Q, was markedly reduced compared with wild type, and functional noradrenaline uptake was detected only for the hE113Q mutant. The pharmacological properties of the hE113Q mutant showed very little change compared with wild type, except for a decrease in Vmax values for noradrenaline and dopamine uptake of 2-3-fold. However, the hE113D mutant showed very marked changes in its properties, compared with wild type, with 82-260-fold decreases in the affinities of the substrates, noradrenaline, dopamine and MPP+, and increased Na+ affinity for stimulation of nisoxetine binding. The results of the study show that the size and not the charge of the 113 glutamate residue of the noradrenaline transporter seems to be the most critical factor for maintenance of transporter function and surface expression.     

A novel biosynthetic pathway providing precursors for fatty acid biosynthesis and secondary metabolite formation in myxobacteria

Short chain carboxylic acids are well known as the precursors of fatty acid and polyketide biosynthesis. Iso-fatty acids, which are important for the control of membrane fluidity, are formed from branched chain starter units (isovaleryl-CoA and isobutyryl-CoA), which in turn are derived from the degradation of leucine and valine, respectively. Branched chain carboxylic acids are also employed as starter molecules for the biosynthesis of secondary metabolites, e.g. the therapeutically important anthelmintic agent avermectin or the electron transport inhibitor myxothiazol. During our studies on myxothiazol biosynthesis in the myxobacterium, Stigmatella aurantiaca, we detected a novel biosynthetic route to isovaleric acid. After cloning and inactivation of the branched chain keto acid dehydrogenase complex, which is responsible for the degradation of branched chain amino acids, the strain is still able to produce iso-fatty acids and myxothiazol. Incorporation studies employing deuterated leucine show that it can only serve as precursor in the wild type strain but not in the esg mutant. Feeding experiments using (13)C-labeled precursors show that isovalerate is efficiently made from acetate, giving rise to a labeling pattern in myxothiazol that provides evidence for a novel branch of the mevalonate pathway involving the intermediate 3,3-dimethylacryloyl-CoA. 3,3-Dimethylacrylic acid was synthesized in deuterated form and fed to the esg mutant, resulting in strong incorporation into myxothiazol and iso-fatty acids. Similar experiments employing Myxococcus xanthus revealed that the discovered biosynthetic route described is present in other myxobacteria as well.     

Isolation of glucocardiolipins from Geobacillus stearothermophilus NRS 2004/3a

Glucose-substituted cardiolipins account for about 4 mol% of total phospholipid extracted from exponentially grown cells of Geobacillus stearothermophilus NRS 2004/3a. Individual glucocardiolipin species exhibited differences in fatty acid substitution, with iso-C(15:0) and anteiso-C(17:0) prevailing. The compounds were purified to homogeneity by a novel protocol and precharacterized by matrix-assisted laser desorption ionization time-of-flight mass spectrometry.     

Erythropoietin therapy for acute stroke is both safe and beneficial

BACKGROUND: Erythropoietin (EPO) and its receptor play a major role in embryonic brain, are weakly expressed in normal postnatal/adult brain and up-regulated upon metabolic stress. EPO protects neurons from hypoxic/ ischemic injury. The objective of this trial is to study the safety and efficacy of recombinant human EPO (rhEPO) for treatment of ischemic stroke in man. MATERIALS AND METHODS: The trial consisted of a safety part and an efficacy part. In the safety study, 13 patients received rhEPO intravenously (3.3 X 10(4) IU/50 ml/30 min) once daily for the first 3 days after stroke. In the double-blind randomized proof-of-concept trial, 40 patients received either rhEPO or saline. Inclusion criteria were age <80 years, ischemic stroke within the middle cerebral artery territory confirmed by diffusion-weighted MRI, symptom onset <8 hr before drug administration, and deficits on stroke scales. The study endpoints were functional outcome at day 30 (Barthel Index, modified Rankin scale), NIH and Scandinavian stroke scales, evolution of infarct size (sequential MRI evaluation using diffusion-weighted [DWI] and fluid-attenuated inversion recovery sequences [FLAIR]) and the damage marker S100ss. RESULTS: No safety concerns were identified. Cerebrospinal fluid EPO increased to 60-100 times that of nontreated patients, proving that intravenously administered rhEPO reaches the brain. In the efficacy trial, patients received rhEPO within 5 hr of onset of symptoms (median, range 2:40-7:55). Admission neurologic scores and serum S100beta concentrations were strong predictors ofoutcome. Analysis of covariance controlled for these two variables indicated that rhEPO treatment was associated with an improvement in follow-up and outcome scales. A strong trend for reduction in infarct size in rhEPO patients as compared to controls was observed by MRI. CONCLUSION: Intravenous high-dose rhEPO is well tolerated in acute ischemic stroke and associated with an improvement in clinical outcome at 1 month. A larger scale clinical trial is warranted.     

Analysis of multidimensional neural activity via CNN-UM

In this paper we show that the Cellular Nonlinear Network Universal Machine (CNN-UM) is an excellent tool for analyzing time series of multidimensional binary signals. The developed algorithm is dedicated to process electrophysiological multi-neuron recordings: our aim is to find specific multidimensional activity patterns, which may reflect higher order functional cell-assemblies. The analysis consists of two parts: first, the occurrences of different patterns are counted, then the statistical significance of each occurrence frequency is calculated separately.     

Molecular and functional characterisation of mild MCAD deficiency

We report a novel mild variant of medium-chain acyl-CoA dehydrogenase deficiency (MCADD) diagnosed in four infants who, in neonatal screening, showed abnormal acylcarnitine profiles indicative of MCADD. Three patients showed completely normal urinary organic acids and phenylpropionic acid loading tests were normal in all four patients. Enzyme studies showed residual MCAD activities between "classical" MCADD and heterozygotes. ACADM gene analysis revealed compound heterozygosity for the common mutation K329E and a novel mutation, Y67H, in two cases, and homozygosity for mutation G267R and the novel mutation S245L, respectively, in two children of consanguineous parents. As in other metabolic disorders, the distinction between "normal" and "disease" in MCAD deficiency is blurring into a spectrum of enzyme deficiency states caused by different mutations in the ACADM gene potentially influenced by factors affecting intracellular protein processing.