Leaf water storage increases with salinity and aridity in the mangrove Avicennia marina: integration of leaf structure,osmotic adjustment and access to multiple water sources

Leaf structure and water relations were studied in a temperate population of Avicennia marina subsp. australasica along a natural salinity gradient [28 to 49 parts per thousand (ppt)] and compared with two subspecies grown naturally in similar soil salinities to those of subsp. australasica but under different climates: subsp. eucalyptifolia (salinity 30 ppt, wet tropics) and subsp. marina (salinity 46 ppt, arid tropics). Leaf thickness, leaf dry mass per area and water content increased with salinity and aridity. Turgor loss point declined with increase in soil salinity, driven mainly by differences in osmotic potential at full turgor. Nevertheless, a high modulus of elasticity (ε) contributed to maintenance of high cell hydration at turgor loss point. Despite similarity among leaves in leaf water storage capacitance, total leaf water storage increased with increasing salinity and aridity. The time that stored water alone could sustain an evaporation rate of 1 mmol m^?2 s^?1 ranged from 77 to 126 min from subspecies eucalyptifolia to ssp. marina, respectively. Achieving full leaf hydration or turgor would require water from sources other than the roots, emphasizing the importance of multiple water sources to growth and survival of Avicennia marina across gradients in salinity and aridity.     

High resolution chromosomal microarray analysis in paediatric obsessive-compulsive disorder

Background

Obsessive-Compulsive Disorder (OCD) is a common and chronic disorder in which a person has uncontrollable, reoccurring thoughts and behaviours. It is a complex genetic condition and, in case of early onset (EO), the patients manifest a more severe phenotype, and an increased heritability. Large (>500 kb) copy number variations (CNVs) previously associated with autism and schizophrenia have been reported in OCD. Recently, rare CNVs smaller than 500 kb overlapping risk loci for other neurodevelopmental conditions have also been reported in OCD, stressing the importance of examining CNVs of any size range. The aim of this study was to further investigate the role of rare and small CNVs in the aetiology of EO-OCD.

Methods

We performed high-resolution chromosomal microarray analysis in 121 paediatric OCD patients and in 124 random controls to identify rare CNVs (>50 kb) which might contribute to EO-OCD.

Results

The frequencies and the size of the observed rare CNVs in the patients did not differ from the controls. However, we observed a significantly higher frequency of rare CNVs affecting brain related genes, especially deletions, in the patients (OR?=?1.98, 95% CI 1.02–3.84; OR?=?3.61, 95% CI 1.14–11.41, respectively). Similarly, enrichment-analysis of CNVs gene content, performed with three independent methods, confirmed significant clustering of predefined genes involved in synaptic/brain related functional pathways in the patients but not in the controls. In two patients we detected de-novo CNVs encompassing genes previously associated with different neurodevelopmental disorders (NRXN1, ANKS1B, UHRF1BP1).

Conclusions

Our results further strengthen the role of small rare CNVs, particularly deletions, as susceptibility factors for paediatric OCD.

     

Control of enteric pathogens in ready-to-eat vegetable crops in organic and 'low input' production systems: a HACCP-based approach

Risks from pathogens such as Salmonella, Yersinia, Campylobacter and Escherichia coli O157 have been identified as a particular concern for organic and 'low input' food production systems that rely on livestock manure as a nutrient source. Current data do not allow any solid conclusions to be drawn about the level of this risk, relative to conventional production systems. This review describes six Risk Reduction Points (RRPs) where risks from enteric pathogens can be reduced in ready-to-eat vegetables. Changes can be made to animal husbandry practices (RRP1) to reduce inoculum levels in manure. Outdoor livestock management (RRP2) can be optimized to eliminate the risk of faecal material entering irrigation water. Manure storage and processing (RRP3), soil management practices (RRP4) and timing of manure application (RRP5), can be adjusted to reduce the survival of pathogens originating from manure. During irrigation (RRP6), pathogen risks can be reduced by choosing a clean water source and minimizing the chances of faecal material splashing on to the crop. Although preventive measures at these RRPs can minimize enteric pathogen risk, zero risk can never be obtained for raw ready-to-eat vegetables. Good food hygiene practices at home are essential to reduce the incidence of food-borne illnesses.     

Identification of differentially expressed proteins in the cervical mucosa of HIV-1-resistant sex workers

Novel tools are necessary to understand mechanisms of altered susceptibility to HIV-1 infection in women of the Pumwani Sex Worker cohort, Kenya. In this cohort, more than 140 of the 2000 participants have been characterized to be relatively resistant to HIV-1 infection. Given that sexual transmission of HIV-1 occurs through mucosal surfaces such as that in the cervicovaginal environment, our hypothesis is that innate immune factors in the genital tract may play a role in HIV-1 infection resistance. Understanding this mechanism may help develop microbicides and/or vaccines against HIV-1. A quantitative proteomics technique (2D-DIGE: two-dimensional difference in-gel electrophoresis) was used to examine cervical mucosa of HIV-1 resistant women ( n = 10) for biomarkers of HIV-1 resistance. Over 15 proteins were found to be differentially expressed between HIV-1-resistant women and control groups ( n = 29), some which show a greater than 8-fold change. HIV-1-resistant women overexpressed several antiproteases, including those from the serpin B family, and also cystatin A, a known anti-HIV-1 factor. Immunoblotting for a selection of the identified proteins confirmed the DIGE volume differences. Validation of these results on a larger sample of individuals will provide further evidence these biomarkers are associated with HIV-1 resistance and could help aid in the development of effective microbicides against HIV-1.     

Broadly neutralizing antibodies protect against hepatitis C virus quasispecies challenge

A major problem in hepatitis C virus (HCV) immunotherapy or vaccine design is the extreme variability of the virus. We identified human monoclonal antibodies (mAbs) that neutralize genetically diverse HCV isolates and protect against heterologous HCV quasispecies challenge in a human liver-chimeric mouse model. The results provide evidence that broadly neutralizing antibodies to HCV protect against heterologous viral infection and suggest that a prophylactic vaccine against HCV may be achievable.     

Cryptic complexity captured: the Nematostella genome reveals its secrets

The full genomic sequence of the sea anemone Nematostella vectensis, which is the first full genomic sequence for a representative of the Phylum Cnidaria, has recently been published, providing some surprising findings and a unique perspective on the evolution of animal genomes. Major conclusions are that, in gene number, composition and intron/exon structure, the anemone is more similar to vertebrates than are flies and nematodes and that this shared complexity must therefore be very ancient.     

The high prevalence of herpes simplex virus type 1 DNA in human trigeminal ganglia is not a function of age or gender

The purpose of this study was to determine the presence and copy numbers of herpes simplex virus type 1 (HSV-1) DNA in human trigeminal ganglia (TG) with respect to age, gender, and postmortem interval (PMI). Human TG (n = 174, obtained from the Oregon Brain Bank, with data on age, gender, and PMI) were analyzed for HSV-1 DNA copies (HSV-1 DNA polymerase gene) by using real-time PCR. We found that 89.1% (131/147) of subjects and 90.1% (155/174) of TG contained HSV-1 DNA. The copy numbers of HSV-1 DNA in the positives ranged from very high (>10⁶) to very low (5). These data confirm and strengthen our previous findings that subjects were positive for HSV-1 DNA in tears (46/50; 92%) and saliva (47/50; 94%). These TG data and tear and saliva data demonstrated considerable variability in copy numbers of HSV-1 DNA per subject. Statistical analysis showed no significant relationship between gender and copy number, age and copy number, or PMI and copy number for each pair of variables. A factorial analysis of gender, age, and PMI with respect to copy number also showed no statistical significance. This is the first study that provides statistical analysis that documents that the prevalence of HSV-1 DNA in the human TG is not a function of either gender or age.     

G2, G3, and complete basis set calculations of the thermodynamic properties of cis- and trans-triazene

Following our recent study on triazane, we present a follow-up study on the thermodynamic properties of triazane’s unsaturated analog, triazene. We predict optimized structural parameters, vibrational frequencies, enthalpies of formation, enthalpies of combustion, specific enthalpies of combustion, and proton affinities. Our results indicate that the cis form of triazene has a specific enthalpy of combustion of −15.2 kJ g⁻¹ and the trans form has a specific enthalpy of combustion of −14.7 kJ g⁻¹. Figure Structures of cis- and trans-triazane, N₃H₃     

Mass spectrometry as a novel approach to probe cooperativity in multimeric enzymatic systems

Investigating cooperativity in multimeric enzymes is of utmost interest to improve our understanding of the mechanism of enzymatic regulation. In the present article, we propose a novel approach based on mass spectrometry to probe cooperativity in the binding of a ligand to a multisubunit enzyme. This approach presents the selective advantage of giving a direct insight into all the subsequent ligation states that are formed in solution as the ligand is added to the enzyme. A quantitative interpretation of the electrospray ionization (ESI) mass spectra gives the relative abundance of all the distinct enzymatic species, which allows one to directly deduce the cooperativity of the system. The overall method is described for the addition of the oxidized cofactor nicotinamide adenine dinucleotide (NAD(+)) to a dimeric mutant of Bacillus stearothermophilus glyceraldehyde-3-phosphate dehydrogenase (GPDH). It is then applied to four tetrameric enzymes: sturgeon muscle GPDH, wild type and S48G mutant of GPDH from B. stearothermophilus, and alcohol dehydrogenase (ADH) from Bakers yeast. The results illustrate the possibilities offered by this new technique. First, mass spectrometry allows a control of the enzymes before the addition of NAD(+). Second, the cooperative behavior can be drawn from one single ESI mass spectrum, which makes the method highly attractive in terms of the amount of biological material required. Above all, the major benefit lies in the direct visualization of all the enzymatic species that are in equilibrium in solution. The direct measurement of cooperativity readily resolve the inconvenience of the classical approaches employed in this field, which all need to model the experimental data in order to get the cooperative behavior of the system.