Patterns in vegetation, hydrology, and nutrient availability in an undisturbed river floodplain in Poland

In the undisturbed floodplain of the Biebrza river (N.E. Poland) wecompared vegetation composition, standing crop and the nutrients in standingcrop to site factors such as flood duration and inundation depth during springfloods, summer water levels and concentrations of chemical constituents inwaterand nutrient release rates from peat. Our analysis shows a number of clearspatial patterns of biotic and abiotic variables in the ca. 1 kmwide river marginal wetland. The distribution of vegetation types follows acertain pattern: Glycerietum maximae close to the river,followed by respectively Caricetum gracilis andCaricetum elatae and finally Calamagrostietumstrictae at the margin of the river plain. Species richnessincreasesand standing crop decreases from the river towards the margin. The elevation ofthe ground surface gently rises with increasing distance from the river; floodduration and flooding depths in spring decrease in the same direction.Groundwater tables in summer are less correlated to the elevation gradient buttend to be closer to the ground surface at the valley margin. These differencesalso lead to a higher amplitude close to the river and a fairly stable watertable far away from the river. Concentrations of major ions and ammoniumincrease towards the river. Nutrient release rates are also higher closer totheriver. Absence and presence of species and the variation in species compositionof the vegetation was explained best by flood variables; variables fromgroundwater explained much less of the variance. Variations in standing cropandnutrients in standing crop corresponded better to the rates of nutrient releasefrom the organic soil than to nutrient concentrations in the soil water. Weconcluded that river hydrology and nutrient release from the soil are clearlyrelated to vegetation composition, species richness and productivity of thevegetation.     

Sources of Blood Meals of Sylvatic Triatoma guasayana near Zurima,Bolivia, Assayed with qPCR and 12S Cloning

Background

In this study we compared the utility of two molecular biology techniques, cloning of the mitochondrial 12S ribosomal RNA gene and hydrolysis probe-based qPCR, to identify blood meal sources of sylvatic Chagas disease insect vectors collected with live-bait mouse traps (also known as Noireau traps). Fourteen T. guasayana were collected from six georeferenced trap locations in the Andean highlands of the department of Chuquisaca, Bolivia.

Methodology/Principal Findings

We detected four blood meals sources with the cloning assay: seven samples were positive for human (Homo sapiens), five for chicken (Gallus gallus) and unicolored blackbird (Agelasticus cyanopus), and one for opossum (Monodelphis domestica). Using the qPCR assay we detected chicken (13 vectors), and human (14 vectors) blood meals as well as an additional blood meal source, Canis sp. (4 vectors).

Conclusions/Significance

We show that cloning of 12S PCR products, which avoids bias associated with developing primers based on a priori knowledge, detected blood meal sources not previously considered and that species-specific qPCR is more sensitive. All samples identified as positive for a specific blood meal source by the cloning assay were also positive by qPCR. However, not all samples positive by qPCR were positive by cloning. We show the power of combining the cloning assay with the highly sensitive hydrolysis probe-based qPCR assay provides a more complete picture of blood meal sources for insect disease vectors.     

Decreased Serum Level of miR-146a as Sign of Chronic Inflammation in Type 2 Diabetic Patients

Background

There is increasing evidence that chronic inflammation is an important determinant in insulin resistance and in the pathogenesis of type 2 diabetes (T2D). MicroRNAs constitute a newly discovered system of cell regulation and in particular two microRNAs (miR-146a and miR-155) have been described as regulators and biomarkers of inflammation.

Aim

To determine a putative association between the levels of miR-146a and miR-155 in serum of T2D patients, clinical parameters and serological indicators of inflammation.

Methods

We performed quantitative Real Time PCR (qPCR) of microRNAs from serum (56 Ecuadorian T2D ambulatory patients and 40 non-diabetic controls). In addition, we evaluated T2D-related serum cytokines.chemokines and growth factors using a commercially available multi-analyte cytometric bead array system. We correlated outcomes to clinical parameters, including BMI, HbA1c and lipid state.

Results

The Ecuadorian non-diabetic controls appeared as overweight (BMI>25: patients 85%, controls 82.5%) and as dyslipidemic (hypercholesterolemia: patients 60.7%, controls 67.5%) as the patients.

• The serum levels of miR-146a were significantly reduced in T2D patients as compared to these non-diabetic, but obese/dyslipidemic control group (mean patients 0.61, mean controls set at 1; p = 0.042), those of miR-155 were normal.
• The serum levels of both microRNAs correlated to each other (r = 0.478; p<0.001) and to leptin levels. The microRNAs did not correlate to BMI, glycemia and dyslipidemia.
• From the tested cytokines, chemokines and growth factors, we found IL-8 and HGF significantly raised in T2D patients versus non-diabetic controls (p = 0.011 and 0.023 respectively).

Conclusions

This study shows decreased serum anti-inflammatory miR-146a, increased pro-inflammatory IL-8 and increased HGF (a vascular/insular repair factor) as discriminating markers of failure of glucose control occurring on the background of obesity and dyslipidemia.     

The alternative sigma factor sigma B of Staphylococcus aureus modulates virulence in experimental central venous catheter-related infections

The impact of the alternative sigma factor sigma B (SigB) on pathogenesis of Staphylococcus aureus is not conclusively clarified. In this study, a central venous catheter (CVC) related model of multiorgan infection was used to investigate the role of SigB for the pathogenesis of S. aureus infections and biofilm formation in vivo. Analysis of two SigB-positive wild-type strains and their isogenic mutants revealed uniformly that the wild-type was significantly more virulent than the SigB-deficient mutant. The observed difference in virulence was apparently not linked to the capability of the strains to form biofilms in vivo since wild-type and mutant strains were able to produce biofilm layers inside of the catheter. The data strongly indicate that the alternative sigma factor SigB plays a role in CVC-associated infections caused by S. aureus.     

Mortality and Life Expectancy in Homeless Men and Women in Rotterdam: 2001–2010

Background

Data on mortality among homeless people are limited. Therefore, this study aimed to describe mortality patterns within a cohort of homeless adults in Rotterdam (the Netherlands) and to assess excess mortality as compared to the general population in that city.

Methods

Based on 10-year follow-up of homeless adults aged ≥ 20 years who visited services for homeless people in Rotterdam in 2001, and on vital statistics, we assessed the association of mortality with age, sex and type of service used (e.g. only day care, convalescence care, other) within the homeless cohort, and also compared mortality between the homeless and general population using Poisson regression. Life tables and decomposition methods were used to examine differences in life expectancy.

Results

During follow-up, of the 2096 adult homeless 265 died. Among the homeless, at age 30 years no significant sex differences were found in overall mortality rates and life expectancy. Compared with the general Rotterdam population, mortality rates were 3.5 times higher in the homeless cohort. Excess mortality was larger in women (rate ratio [RR] RR 5.56, 95% CI 3.95–7.82) as compared to men (RR 3.31, 95% CI 2.91–3.77), and decreased with age (RR 7.67, 95% CI 6.87–8.56 for the age group 20–44 and RR 1.63, 95% CI 1.41–1.88 for the age group 60+ years). Life expectancy at age 30 years was 11.0 (95% CI 9.1–12.9) and 15.9 (95% CI 10.3–21.5) years lower for homeless men and women compared to men and women in the general population respectively.

Conclusion

Homeless adults face excessive losses in life expectancy, with greatest disadvantages among homeless women and the younger age groups.     

Screening Accuracy and Clinical Application of the Brief Infant-Toddler Social and Emotional Assessment (BITSEA)

Background

The Brief Infant-Toddler Social and Emotional Assessment (BITSEA) is a promising questionnaire for the early detection of psychosocial problems in toddlers. The screening accuracy and clinical application were evaluated.

Methods

In a community sample of 2-year-olds (N = 2060), screening accuracy of the BITSEA Problem scale was examined regarding a clinical CBCL1.5-5 Total Problem score. For the total population and subgroups by child’s gender and ethnicity Receiver Operating Characteristic (ROC) curves were calculated, and across a range of BITSEA Problem scores, sensitivity, specificity, likelihood ratio’s, diagnostic odds ratio and Youden’s index. Clinical application of the BITSEA was examined by evaluating the relation between the scale scores and the clinical decision of the child health professional.

Results

The area under the ROC curve (95% confidence interval) of the Problem scale was 0.97(0.95–0.98), there were no significant differences between subgroups. The association between clinical decision and BITSEA Problem score (B = 2.5) and Competence score (B = −0.7) was significant (p<0.05).

Conclusions

The results indicate that the BITSEA Problem scale has good discriminative power to differentiate children with and without psychosocial problems. Referred children had less favourable scores compared to children that were not referred. The BITSEA may be helpful in the early detection of psychosocial problems.     

In situ localization of gelatinolytic activity in the extracellular matrix of metastases of colon cancer in rat liver using quenched fluorogenic DQ-gelatin.

Matrix metalloproteinases (MMPs) such as gelatinases are believed to play an important role in invasion and metastasis of cancer. In this study we investigated the possible role of MMP-2 and MMP-9 in an experimental model of colon cancer metastasis in rat liver. We demonstrated with gelatin zymography that the tumors contained MMP-2 and MMP-9, but only MMP-2 was present in the active form. Immunolocalization of MMP-2 showed that the protein was localized at basement membranes of colon cancer cells and in intratumor stroma, associated with extracellular matrix (ECM) components. However, zymography and immunohistochemistry (IHC) do not provide information on the localization of MMP activity. Therefore, we developed an in situ zymography technique using the quenched fluorogenic substrate DQ-gelatin in unfixed cryostat sections. The application of DQ-gelatin in combination with a gelled medium allows precise localization of gelatinolytic activity. Fluorescence due to gelatinolytic activity was found in the ECM of tumors and was localized similarly to both MMP-2 protein and collagen type IV, its natural substrate. The localization of MMP-2 activity and collagen type IV at similar sites suggests a role of MMP-2 in remodeling of ECM of stroma in colon cancer metastases in rat liver.     

MiRNA Expression May Account for Chronic but Not for Acute Regulation of mRNA Expression in Human Thyroid Tumor Models

Background

For thyroid tumorigenesis, two main human in vitro models are available: primary cultures of human thyrocytes treated with TSH or EGF/serum as models for autonomous adenomas (AA) or papillary thyroid carcinomas (PTC) respectively, and human thyroid tumor derived cell lines. Previous works of our group have assessed properties of those models, with a special emphasis on mRNA regulations. It is often assumed that miRNA may be one of the primary events inducing these mRNA regulations.

Methods

The purpose of this study was to investigate the representativity of those models to study microRNA regulations and their relation with mRNA expression. To achieve this aim, the miRNA expressions profiles of primary cultures treated with TSH or EGF/serum and of 6 thyroid cancer cell lines were compared to the expression profiles of 35 tumor tissues obtained by microarrays.

Results

Our data on primary cultures have shown that the TSH or EGF/serum treatment did not greatly modify the microRNA expression profiles, which is contrary to what is observed for mRNA expression profiles, although they still evolved differently according to the treatment. The analysis of miRNA and mRNA expressions profiles in the cell lines has shown that they have evolved into a common, dedifferentiated phenotype, closer to ATC than to the tumors they are derived from.

Conclusions

Long-terms TSH or EGF/serum treatments do not mimic AA or PTC respectively in terms of miRNA expression as they do for mRNA, suggesting that the regulations of mRNA expression induced by these physiological agents occur independently of miRNA. The general patterns of miRNA expression in the cell lines suggest that they represent a useful model for undifferentiated thyroid cancer. Mirna probably do not mediate the rapid changes in gene expression in rapid cell biology regulation.