Antibiotic-induced change of bacterial communities associated with the copepod Nitocra spinipes

Environmental pressures, such as physical factors, diet and contaminants may affect interactions between microbial symbionts and their multicellular hosts. Despite obvious relevance, effects of antimicrobial contaminants on host-symbiont relations in non-target aquatic organisms are largely unknown. We show that exposure to antibiotics had negative effects on survival and juvenile development of the copepod Nitocra spinipes and caused significant alterations in copepod-associated bacterial communities. The significant positive correlations between indices of copepod development and bacterial diversity indicate that disruption of the microflora was likely to be an important factor behind retarded juvenile development in the experimental animals. Moreover, as evidenced by ribotype distribution in the bacterial clone libraries, the exposure to antibiotics caused a shift in dominance from Betaproteobacteria to Cardinium bacteria; the latter have been shown to cause reproductive manipulations in various terrestrial arthropods. Thus, in addition to providing evidence that the antibiotic-induced perturbation of the microbial community associates with reductions in fitness-related traits of the host, this study is the first record of a copepod serving as a host for endosymbiotic Cardinium. Taken together, our results suggest that (1) antimicrobial substances and possibly other stressors can affect micobiome and symbiont-mediated interactions in copepods and other hosts, and (2) Cardinium endosymbionts may occur in other copepods and affect reproduction of their hosts.     

Dimethylarginine Dimethylaminohydrolase1 Is an Organ-Specific Mediator of End Organ Damage in a Murine Model of Hypertension

Background

The endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA) is an independent predictor of cardiovascular and overall mortality. Moreover, elevated ADMA plasma concentrations are associated with the extent of hypertension. However, data from small-sized clinical trials and experimental approaches using murine transgenic models have revealed conflicting results regarding the impact of ADMA and its metabolizing enzyme dimethylarginine dimethylaminohydrolase (DDAH) in the pathogenesis of hypertension.

Methodology/Principal Findings

Therefore, we investigated the role of ADMA and DDAH1 in hypertension-induced end organ damage using the uninephrectomized, deoxycorticosterone actetate salt, and angiotensin II-induced hypertension model in human DDAH1 (hDDAH1) overexpressing and wild-type (WT) mice. ADMA plasma concentrations differed significantly between hDDAH1 and WT mice at baseline, but did not significantly change during the induction of hypertension. hDDAH1 overexpression did not protect against hypertension-induced cardiac fibrosis and hypertrophy. In addition, the hypertension-induced impairment of the endothelium-dependent vasorelaxation of aortic segments ex vivo was not significantly attenuated by hDDAH1 overexpression. However, hDDAH1 mice displayed an attenuated hypertensive inflammatory response in renal tissue, resulting in less hypertensive renal injury.

Conclusion/Significance

Our data reveal that hDDAH1 organ-specifically modulates the inflammatory response in this murine model of hypertension. The lack of protection in cardiac and aortic tissues may be due to DDAH1 tissue selectivity and/or the extent of hypertension by the used combined model. However, our study underlines the potency of hDDAH1 overexpression in modulating inflammatory processes as a crucial step in the pathogenesis of hypertension, which needs further experimental and clinical investigation.     

Fatty acids in ADHD: plasma profiles in a placebo-controlled study of Omega 3/6 fatty acids in children and adolescents

The aim of this study was to assess baseline levels and changes in plasma fatty acid profiles in children and adolescents with ADHD, in a placebo-controlled study with Omega 3/6 supplementation, and to compare with treatment response. Seventy-five children and adolescents aged 8?C18?years with DSM-IV ADHD were randomized to 3?months of Omega 3/6 (Equazen eye q) or placebo, followed by 3?months of open phase Omega 3/6 for all. n-3, n-6, n-6/n-3 ratio, EPA and DHA in plasma were measured at baseline, 3 and 6?months. Subjects with more than 25?% reduction in ADHD symptoms were classified as responders. At baseline, no significant differences in mean fatty acid levels were seen across active/placebo groups or responder/non-responder groups. The 0?C3?month changes in all parameters were significantly greater in the active group (p?<?0.01). Compared to non-responders, the 6-month responders had significantly greater n-3 increase at 3?months and decrease in n-6/n-3 ratio at 3 and 6?months (p?<?0.05). Omega 3/6 supplementation had a clear impact on fatty acid composition of plasma phosphatidyl choline in active versus placebo group, and the fatty acid changes appear to be associated with treatment response. The most pronounced and long-lasting changes for treatment responders compared to non-responders were in the n-6/n-3 ratio.     

Genetic Variation in the Epidermal Transglutaminase Genes Is Not Associated with Atopic Dermatitis

Background

Atopic dermatitis (AD) is a common chronic inflammatory skin disorder where epidermal barrier dysfunction is a major factor in the pathogenesis. The identification of AD susceptibility genes related to barrier dysfunction is therefore of importance. The epidermal transglutaminases (TGM1, TGM3 and TGM5) encodes essential cross-linking enzymes in the epidermis.

Objective

To determine whether genetic variability in the epidermal transglutaminases contributes to AD susceptibility.

Methods

Forty-seven single nucleotide polymorphisms (SNPs) in the TGM1, TGM3 and TGM5 gene region were tested for genetic association with AD, independently and in relation to FLG genotype, using a pedigree disequilibrium test (PDT) in a Swedish material consisting of 1753 individuals from 539 families. In addition, a German case-control material, consisting of 533 AD cases and 1996 controls, was used for in silico analysis of the epidermal TGM regions. Gene expression of the TGM1, TGM3 and TGM5 gene was investigated by relative quantification with Real Time PCR (qRT-PCR). Immunohistochemical (IHC) analysis was performed to detect TG1, TG3 and TG5 protein expression in the skin of patients and healthy controls.

Results

PDT analysis identified a significant association between the TGM1 SNP rs941505 and AD with allergen-specific IgE in the Swedish AD family material. However, the association was not replicated in the German case-control material. No significant association was detected for analyzed SNPs in relation to FLG genotype. TG1, TG3 and TG5 protein expression was detected in AD skin and a significantly increased TGM3 mRNA expression was observed in lesional skin by qRT-PCR.

Conclusion

Although TGM1 and TGM3 may be differentially expressed in AD skin, the results from the genetic analysis suggest that genetic variation in the epidermal transglutaminases is not an important factor in AD susceptibility.     

Proton-Coupled Dynamics in Lactose Permease

1. Download : Download high-res image (525KB)
2. Download : Download full-size image

Highlights? Deprotonation of Glu325 brings H⁺ translocation and sugar-binding sites together ? Deprotonation of Glu325 closes the internal water-filled cytoplasmic cavity ? Deprotonated LacY inserted into DMPC lipids shows no structural rearrangements ? The structural changes show remarkable similarities to experimental observations     

Thermal optimality of net ecosystem exchange of carbon dioxide and underlying mechanisms

? It is well established that individual organisms can acclimate and adapt to temperature to optimize their functioning. However, thermal optimization of ecosystems, as an assemblage of organisms, has not been examined at broad spatial and temporal scales. ? Here, we compiled data from 169 globally distributed sites of eddy covariance and quantified the temperature response functions of net ecosystem exchange (NEE), an ecosystem-level property, to determine whether NEE shows thermal optimality and to explore the underlying mechanisms. ? We found that the temperature response of NEE followed a peak curve, with the optimum temperature (corresponding to the maximum magnitude of NEE) being positively correlated with annual mean temperature over years and across sites. Shifts of the optimum temperature of NEE were mostly a result of temperature acclimation of gross primary productivity (upward shift of optimum temperature) rather than changes in the temperature sensitivity of ecosystem respiration. ? Ecosystem-level thermal optimality is a newly revealed ecosystem property, presumably reflecting associated evolutionary adaptation of organisms within ecosystems, and has the potential to significantly regulate ecosystem-climate change feedbacks. The thermal optimality of NEE has implications for understanding fundamental properties of ecosystems in changing environments and benchmarking global models.     

Clara cell protein in nasal lavage fluid and nasal nitric oxide - biomarkers with anti-inflammatory properties in allergic rhinitis

Background

Clara cell protein (CC16) is ascribed a protective and anti-inflammatory role in airway inflammation. Lower levels have been observed in asthmatic subjects as well as in subjects with intermittent allergic rhinitis than in healthy controls. Nasal nitric oxide (nNO) is present in high concentrations in the upper airways, and considered a biomarker with beneficial effects, due to inhibition of bacteria and viruses along with stimulation of ciliary motility. The aim of this study was to evaluate the presumed anti-inflammatory effects of nasal CC16 and nNO in subjects with allergic rhinitis.

Methods

The levels of CC16 in nasal lavage fluids, achieved from subjects with persistent allergic rhinitis (n = 13), intermittent allergic rhinitis in an allergen free interval (n = 5) and healthy controls (n = 7), were analyzed by Western blot. The levels of nNO were measured by the subtraction method using NIOX^?. The occurrences of effector cells in allergic inflammation, i.e. metachromatic cells (MC, mast cells and basophiles) and eosinophils (Eos) were analyzed by light microscopy in samples achieved by nasal brushing.

Results

The levels of CC16 correlated with nNO levels (r² = 0.37; p = 0.02) in allergic subjects. The levels of both biomarkers showed inverse relationships with MC occurrence, as higher levels of CC16 (p = 0.03) and nNO (p = 0.05) were found in allergic subjects with no demonstrable MC compared to the levels in subjects with demonstrable MC. Similar relationships, but not reaching significance, were observed between the CC16 and nNO levels and Eos occurrence. The levels of CC16 and nNO did not differ between the allergic and the control groups.

Conclusions

The correlation between nasal CC16 and nNO levels in patients with allergic rhinitis, along with an inverse relationship between their levels and the occurrences of MC in allergic inflammation, may indicate that both biomarkers have anti-inflammatory effects by suppression of cell recruitment. The mechanisms behind these observations warrant further analyses.     

Comparison of extraction methods for the comprehensive analysis of mouse brain proteome using shotgun-based mass spectrometry

This study compares 16 different extraction methods for the comprehensive extraction of mouse brain proteome in combination with "shotgun"-based mass spectrometry (MS). Membrane proteins (MPs) are responsible for a large part of the regulatory functions of the cell and are therefore of great interest to extract and analyze. Sixteen protein extraction protocols were evaluated in regards to protein yield and number of identified proteins with emphasis on MPs. The extracted proteins were delipidated, on-filter digested, and analyzed by reversed phase nanoliquid chromatography (RP-nanoLC) in combination with electrospray ionization (ESI) tandem mass spectrometry (MS/MS) using a 7 T hybrid LTQ-FT mass spectrometer. Detergent-based lysis buffers showed higher efficiencies and yields in the extraction of proteins from the brain tissue compared to solubilization with organic solvents or organic acids. The detergent octyl-β-D-glucopyranoside gave the highest number of identified proteins (541) as well as numbers and percentages of identified MPs (29%). Detergent-based protocols are the best sample preparation tools for central nervous system (CNS) tissue and can readily be applied to screen for candidate biomarkers of neurological diseases.