Stomatal response to air humidity and its relation to stomatal density in a wide range of warm climate species

The gas exchange of 19 widely different warm climate species was observed at different leaf to air vapour pressure deficits (VPD). In all species stomata tended to close as VPD increased resulting in a decrease in net photosynthesis. The absolute reduction in leaf conductance per unit increase in VPD was greatest in those species which had a large leaf conductance at low VPDs. This would be expected even if stomata of all species were equally sensitive. However the percentage reduction in net photosynthesis (used as a measure of the relative sensitivity of stomata of the different species) was also closely related to the maximal conductance at low VPD. Similarily the relative sensitivity of stomata to changes in VPD was closely related to the weighted stomatal density or crowding index.The hypothesis is presented that stomatal closure at different VPDs is related to peristomatal evaporation coupled with a high resistance between the epidermis and the mesophyll and low resistance between the stomatal apparatus and the epidermal cells. This hypothesis is consistent with the greater relative sensitivity of stomata on leaves with a high crowding index.The results and the hypothesis are discussed in the light of selection, for optimal productivity under differing conditions of relative humidity and soil water availablility, by observation of stomatal density and distribution on the two sides of the leaf.Visiting scientist, plant physiologist and research assitant of the Cassava Program     

Relationship between Urinary Level of Phytate and Valvular Calcification in an Elderly Population: A Cross-Sectional Study

Pathological calcification generally consists of the formation of solid deposits of hydroxyapatite (calcium phosphate) in soft tissues. Supersaturation is the thermodynamic driving force for crystallization, so it is believed that higher blood levels of calcium and phosphate increase the risk of cardiovascular calcification. However several factors can promote or inhibit the natural process of pathological calcification. This cross-sectional study evaluated the relationship between physiological levels of urinary phytate and heart valve calcification in a population of elderly out subjects. A population of 188 elderly subjects (mean age: 68 years) was studied. Valve calcification was measured by echocardiography. Phytate determination was performed from a urine sample and data on blood chemistry, end-systolic volume, concomitant diseases, cardiovascular risk factors, medication usage and food were obtained. The study population was classified in three tertiles according to level of urinary phytate: low (<0.610 μM), intermediate (0.61–1.21 μM), and high (>1.21 μM). Subjects with higher levels of urinary phytate had less mitral annulus calcification and were less likely to have diabetes and hypercholesterolemia. In the multivariate analysis, age, serum phosphorous, leukocytes total count and urinary phytate excretion appeared as independent factors predictive of presence of mitral annulus calcification. There was an inverse correlation between urinary phytate content and mitral annulus calcification in our population of elderly out subjects. These results suggest that consumption of phytate-rich foods may help to prevent cardiovascular calcification evolution.     

Alcohol Consumption in Midlife and Cognitive Performance Assessed 13 Years Later in the SU.VI.MAX 2 Cohort

Background

Associations between alcohol consumption and cognitive function are discordant and data focusing on midlife exposure are scarce.

Objective

To estimate the association between midlife alcohol consumption and cognitive performance assessed 13 y later while accounting for comorbidities and diet.

Methods

3,088 French middle-aged adults included in the SU.VI.MAX (1994) study with available neuropsychological evaluation 13 y later. Data on alcohol consumption were obtained from repeated 24h dietary records collected in 1994–1996. Cognitive performance was assessed in 2007–2009 via a battery of 6 neuropsychological tests. A composite score was built as the mean of the standardized individual test scores (mean = 50, SD = 10). ANCOVA were performed to estimate mean differences in cognitive performance and 95% confidence intervals (CI).

Results

In women, abstainers displayed lower cognitive scores than did low-to-moderate alcohol drinkers (1 to 2 drinks/day) (mean difference = −1.77; 95% CI: −3.29, −0.25). In men, heavy drinkers (>3 drinks/day) had higher cognitive scores than did low-to-moderate (1 to 3 drinks/day) (mean difference = 1.05; 95% CI: 0.10, 1.99). However, a lower composite cognitive score was detected in male drinkers consuming ≥90 g/d (≈8 drinks/d). A higher proportion of alcohol intake from beer was also associated with lower cognitive scores. These associations remained significant after adjustment for diet, comorbidities and sociodemographic factors.

Conclusion

In men, heavy but not extreme drinking was associated with higher global cognitive scores. Given the known harmful effects of alcohol even in low doses regarding risk of cancer, the study does not provide a basis for modifying current public health messages.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00272428","term_id":"NCT00272428"}}NCT00272428     

Detection of Peptide-Based Nanoparticles in Blood Plasma by ELISA

AimsThe aim of the current study was to develop a method to detect peptide-linked nanoparticles in blood plasma.ResultsThe ELISA based method for the detection of FITC labeled peptides had a detection limit of 1 ng/mL. We were able to accurately measure peptides bound to pentafluorophenyl methacrylate nanoparticles in blood plasma of rats, and similar results were obtained by LC/MS.ConclusionsWe detected FITC-labeled peptides on pentafluorophenyl methacrylate nanoparticles after injection in vivo. This method can be extended to detect nanoparticles with different chemical compositions.     

Serotypes and Clonal Diversity of Streptococcus pneumoniae Causing Invasive Disease in the Era of PCV13 in Catalonia,Spain

The aim of this study was to study the serotypes and clonal diversity of pneumococci causing invasive pneumococcal disease in Catalonia, Spain, in the era of 13-valent pneumococcal conjugate vaccine (PCV13). In our region, this vaccine is only available in the private market and it is estimated a PCV13 vaccine coverage around 55% in children. A total of 1551 pneumococcal invasive isolates received between 2010 and 2013 in the Molecular Microbiology Department at Hospital Sant Joan de Déu, Barcelona, were included. Fifty-two serotypes and 249 clonal types—defined by MLST—were identified. The most common serotypes were serotype 1 (n = 182; 11.7%), 3 (n = 145; 9.3%), 19A (n = 137; 8.8%) and 7F (n = 122; 7.9%). Serotype 14 was the third most frequent serotype in children < 2 years (15 of 159 isolates). PCV7 serotypes maintained their proportion along the period of study, 16.6% in 2010 to 13.4% in 2013, whereas there was a significant proportional decrease in PCV13 serotypes, 65.3% in 2010 to 48.9% in 2013 (p<0.01). This decrease was mainly attributable to serotypes 19A and 7F. Serotype 12F achieved the third position in 2013 (n = 22, 6.4%). The most frequent clonal types found were ST306 (n = 154, 9.9%), ST191 (n = 111, 7.2%), ST989 (n = 85, 5.5%) and ST180 (n = 80, 5.2%). Despite their decrease, PCV13 serotypes continue to be a major cause of disease in Spain. These results emphasize the need for complete PCV13 vaccination.     

Insulin regulates GLUT1-mediated glucose transport in MG-63 human osteosarcoma cells

Osteosarcoma is the most common type of malignant bone cancer, accounting for 35% of primary bone malignancies. Because cancer cells utilize glucose as their primary energy substrate, the expression and regulation of glucose transporters (GLUT) may be important in tumor development and progression. GLUT expression has not been studied previously in human osteosarcoma cell lines. Furthermore, although insulin and insulin-like growth factor (IGF-I) play an important role in cell proliferation and tumor progression, the role of these hormones on GLUT expression and glucose uptake, and their possible relation to osteosarcoma, have also not been studied. We determined the effect of insulin and IGF-I on GLUT expression and glucose transport in three well-characterized human osteosarcoma cell lines (MG-63, SaOs-2, and U2-Os) using immunocytochemical, RT-PCR and functional kinetic analyses. Furthermore we also studied GLUT isoform expression in osteosarcoma primary tumors and metastases by in situ hybridization and immunohistochemical analyses. RT-PCR and immunostaining show that GLUT1 is the main isoform expressed in the cell lines and tissues studied, respectively. Immunocytochemical analysis shows that although insulin does not affect levels of GLUT1 expression it does induce a translocation of the transporter to the plasma membrane. This translocation is associated with increased transport of glucose into the cell. GLUT1 is the main glucose transporter expressed in osteosarcoma, furthermore, this transporter is regulated by insulin in human MG-63 cells. One possible mechanism through which insulin is involved in cancer progression is by increasing the amount of glucose available to the cancer cell.     

Molecular Epidemiology of Human Oral Chagas Disease Outbreaks in Colombia

Background

Trypanosoma cruzi, the causative agent of Chagas disease, displays significant genetic variability revealed by six Discrete Typing Units (TcI-TcVI). In this pathology, oral transmission represents an emerging epidemiological scenario where different outbreaks associated to food/beverages consumption have been reported in Argentina, Bolivia, Brazil, Ecuador and Venezuela. In Colombia, six human oral outbreaks have been reported corroborating the importance of this transmission route. Molecular epidemiology of oral outbreaks is barely known observing the incrimination of TcI, TcII, TcIV and TcV genotypes.

Methodology and Principal Findings

High-throughput molecular characterization was conducted performing MLMT (Multilocus Microsatellite Typing) and mtMLST (mitochondrial Multilocus Sequence Typing) strategies on 50 clones from ten isolates. Results allowed observing the occurrence of TcI, TcIV and mixed infection of distinct TcI genotypes. Thus, a majority of specific mitochondrial haplotypes and allelic multilocus genotypes associated to the sylvatic cycle of transmission were detected in the dataset with the foreseen presence of mitochondrial haplotypes and allelic multilocus genotypes associated to the domestic cycle of transmission.

Conclusions

These findings suggest the incrimination of sylvatic genotypes in the oral outbreaks occurred in Colombia. We observed patterns of super-infection and/or co-infection with a tailored association with the severe forms of myocarditis in the acute phase of the disease. The transmission dynamics of this infection route based on molecular epidemiology evidence was unraveled and the clinical and biological implications are discussed.     

Modulation of the immune response induced by gene electrotransfer of a hepatitis C virus DNA vaccine in nonhuman primates

Induction of multispecific, functional CD4+ and CD8+ T cells is the immunological hallmark of acute self-limiting hepatitis C virus (HCV) infection in humans. In the present study, we showed that gene electrotransfer (GET) of a novel candidate DNA vaccine encoding an optimized version of the nonstructural region of HCV (from NS3 to NS5B) induced substantially more potent, broad, and long-lasting CD4+ and CD8+ cellular immunity than naked DNA injection in mice and in rhesus macaques as measured by a combination of assays, including IFN-gamma ELISPOT, intracellular cytokine staining, and cytotoxic T cell assays. A protocol based on three injections of DNA with GET induced a substantially higher CD4+ T cell response than an adenovirus 6-based viral vector encoding the same Ag. To better evaluate the immunological potency and probability of success of this vaccine, we have immunized two chimpanzees and have compared vaccine-induced cell-mediated immunity to that measured in acute self-limiting infection in humans. GET of the candidate HCV vaccine led to vigorous, multispecific IFN-gamma+CD8+ and CD4+ T lymphocyte responses in chimpanzees, which were comparable to those measured in five individuals that cleared spontaneously HCV infection. These data support the hypothesis that T cell responses elicited by the present strategy could be beneficial in prophylactic vaccine approaches against HCV.     

Behavior of an Aeromonas hydrophila aroA Live Vaccine in Water Microcosms

Genetically modified auxotrophic mutants of different fish pathogens have been used as live vaccines in laboratory experiments, but the behavior of the strains after release into aquatic ecosystems has not been characterized. We previously constructed and characterized an aroA mutant of Aeromonas hydrophila and studied the protection afforded by this mutant as a live vaccine in rainbow trout. In this work, we describe the survival of this strain in aquatic microcosms prepared from fish water tanks. The aroA mutant disappeared rapidly in nonfiltered, nonautoclaved fish tank water, declining below detection levels after 15 days, suggesting an inhibitory effect of the autochthonous microflora of the water. When the aroA strain was used to inoculate sterilized water, its culturability was lower than that of wild-type strain A. hydrophila AG2; after long periods of incubation, aroA cells were able to enter a viable but nonculturable state. Entry into this nonculturable state was accompanied by changes in the cell morphology from rods to spheres, but the cells appeared to remain potentially viable, as assessed by the preservation of cell membrane integrity. Supplementation of the culture medium with sodium pyruvate favored the culturability and resuscitation of the two A. hydrophila strains at low temperatures (6 and 16°C). These results contribute to a better understanding of the behavior of the aroA strain in natural environments and suggest that the inactivation of the aroA gene may be beneficial for the safety of this live vaccine for aquacultures.