Detection of K1 antigen of Escherichia coli rods isolated from pregnant women and neonates

The K1 antigen is an important virulence determinant of Escherichia coli strains and has been shown to be associated particularly with neonatal meningitis, bacteraemia and septicaemia. Thus, its detection seems to be useful, especially in the case of E. coli strains isolated from pregnant women and newborns. In this study, the sensitivity and specificity of the latex agglutination test (Pastorex Meningitis) for identification of E. coli serogroup K1 were assessed, using PCR as the gold standard. Our results showed that consistency of results between latex agglutination test and PCR amounted to 98.5 %. Therefore, Pastorex Meningitis is a good alternative to PCR and could be used for rapid K1 antigen detection, especially in local non-specialized laboratories with limited resources where PCR assay is not applied.     

Lithocholic acid extends longevity of chronologically aging yeast only if added at certain critical periods of their lifespan

Our studies revealed that LCA (lithocholic bile acid) extends yeast chronological lifespan if added to growth medium at the time of cell inoculation. We also demonstrated that longevity in chronologically aging yeast is programmed by the level of metabolic capacity and organelle organization that they developed before entering a quiescent state and, thus, that chronological aging in yeast is likely to be the final step of a developmental program progressing through at least one checkpoint prior to entry into quiescence. Here, we investigate how LCA influences longevity and several longevity-defining cellular processes in chronologically aging yeast if added to growth medium at different periods of the lifespan. We found that LCA can extend longevity of yeast under CR (caloric restriction) conditions only if added at either of two lifespan periods. One of them includes logarithmic and diauxic growth phases, whereas the other period exists in early stationary phase. Our findings suggest a mechanism linking the ability of LCA to increase the lifespan of CR yeast only if added at either of the two periods to its differential effects on various longevity-defining processes. In this mechanism, LCA controls these processes at three checkpoints that exist in logarithmic/diauxic, post-diauxic and early stationary phases. We therefore hypothesize that a biomolecular longevity network progresses through a series of checkpoints, at each of which (1) genetic, dietary and pharmacological anti-aging interventions modulate a distinct set of longevity-defining processes comprising the network; and (2) checkpoint-specific master regulators monitor and govern the functional states of these processes.     

Impact of AT2 Receptor Deficiency on Postnatal Cardiovascular Development

Background

The angiotensin II receptor subtype 2 (AT2 receptor) is ubiquitously and highly expressed in early postnatal life. However, its role in postnatal cardiac development remained unclear.

Methodology/Principal Findings

Hearts from 1, 7, 14 and 56 days old wild-type (WT) and AT2 receptor-deficient (KO) mice were extracted for histomorphometrical analysis as well as analysis of cardiac signaling and gene expression. Furthermore, heart and body weights of examined animals were recorded and echocardiographic analysis of cardiac function as well as telemetric blood pressure measurements were performed. Moreover, gene expression, sarcomere shortening and calcium transients were examined in ventricular cardiomyocytes isolated from both genotypes. KO mice exhibited an accelerated body weight gain and a reduced heart to body weight ratio as compared to WT mice in the postnatal period. However, in adult KO mice the heart to body weight ratio was significantly increased most likely due to elevated systemic blood pressure. At postnatal day 7 ventricular capillarization index and the density of α-smooth muscle cell actin-positive blood vessels were higher in KO mice as compared to WT mice but normalized during adolescence. Echocardiographic assessment of cardiac systolic function at postnatal day 7 revealed decreased contractility of KO hearts in response to beta-adrenergic stimulation. Moreover, cardiomyocytes from KO mice showed a decreased sarcomere shortening and an increased peak Ca²⁺ transient in response to isoprenaline when stimulated concomitantly with angiotensin II.

Conclusion

The AT2 receptor affects postnatal cardiac growth possibly via reducing body weight gain and systemic blood pressure. Moreover, it moderately attenuates postnatal vascularization of the heart and modulates the beta adrenergic response of the neonatal heart. These AT2 receptor-mediated effects may be implicated in the physiological maturation process of the heart.     

Risk factors associated with negative in-vivo diagnostic results in bovine tuberculosis-infected cattle in Spain

Background

Despite great effort and investment incurred over decades to control bovine tuberculosis (bTB), it is still one of the most important zoonotic diseases in many areas of the world. Test-and-slaughter strategies, the basis of most bTB eradication programs carried out worldwide, have demonstrated its usefulness in the control of the disease. However, in certain countries, eradication has not been achieved due in part to limitations of currently available diagnostic tests. In this study, results of in-vivo and post-mortem diagnostic tests performed on 3,614 animals from 152 bTB-infected cattle herds (beef, dairy, and bullfighting) detected in 2007–2010 in the region of Castilla y León, Spain, were analyzed to identify factors associated with positive bacteriological results in cattle that were non-reactors to the single intradermal tuberculin test, to the interferon-gamma (IFN-γ) assay, or to both tests applied in parallel (Test negative/Culture + animals, T-/C+). The association of individual factors (age, productive type, and number of herd-tests performed since the disclosure of the outbreak) with the bacteriology outcome (positive/negative) was analyzed using a mixed multivariate logistic regression model.

Results

The proportion of non-reactors with a positive post-mortem result ranged from 24.3% in the case of the SIT test to 12.9% (IFN-γ with 0.05 threshold) and 11.9% (95% CI 9.9-11.4%) using both tests in parallel. Older (>4.5 years) and bullfighting cattle were associated with increased odds of confirmed bTB infection by bacteriology, whereas dairy cattle showed a significantly lower risk. Ancillary use of IFN-γ assay reduced the proportion of T-/C + animals in high risk groups.

Conclusions

These results demonstrate the likelihood of positive bacteriological results in non-reactor cattle is influenced by individual epidemiological factors of tested animals. Increased surveillance on non-reactors with an increased probability of being false negative could be helpful to avoid bTB persistence, particularly in chronically infected herds. These findings may aid in the development of effective strategies for eradication of bTB in Spain.     

Spiral grain in bristlecone pines (Pinus longaeva) exhibits no correlation with environmental factors

Six hundred and eleven Great Basin bristlecone pines (Pinus longaeva) were surveyed in two separate groves in California’s White Mountains. The presence and direction of spiral grain were recorded for each tree as well as elevation above sea level, horizon angles, latitude and longitude, trunk diameter, whether the tree was dead, and whether the trunk was broken. The proportions of left-handed, right-handed and straight trees were similar in every part of both groves, although the groves lie at different elevations. No significant correlation was found between the direction of spiral grain and any environmental factor. The hypothesis that spiral grain is an adaptation to distribute sap evenly between the roots and the crown in Pinus longaeva is not strongly supported, since spiral grain is not correlated with asymmetric environments and most trees exhibit <90° rotation through the main stem. The data also do not support the idea that spiral grain makes the tree more resistant to breaking in strong winds. Right-handed spiral grain is predicted by this hypothesis, but most bristlecone pines are either left-handed or exhibit no spiral grain. Bristlecone pines are often uprooted from thin soils by strong winds, but rarely are the main stems broken by this mechanism. Spiral grain in Pinus longaeva growing in California’s White Mountains does not appear to be under environmental control.     

Morphological delineation and distribution patterns of four newly described species within the Synura petersenii species complex (Chrysophyceae,Stramenopiles)

The Synura petersenii species complex represents a common, cosmopolitan and highly diverse taxon of autotrophic freshwater flagellates. In this paper, we describe and characterize four new species (S. borealis, S. heteropora, S. hibernica and S. laticarina) that have been identified during our extensive sampling of freshwater habitats in 15 European countries. Morphometric analyses of siliceous scales led to the significant phenotypic differentiation of all four newly described species, and their separation from other related species of the S. petersenii complex. Two of these newly described species (S. hibernica and S. borealis) can be clearly distinguished by characteristic large colonies consisting of elongated, lanceolate-shaped cells. Development of strongly elongated, narrow cells in S. hibernica could be explained by the adaptation of this species to oligotrophic conditions. Though morphologically distinct, S. borealis possesses an exceptionally high degree of genetic diversity, possibly indicating recent speciation and evolutionary diversification within this taxon. Three of the four newly described species exhibit restricted biogeographic distribution. The evolutionarily related S. borealis and S. laticarina occur only in Northern Europe, and seem to be adapted to colder areas. The most remarkable distribution pattern was observed for S. hibernica, which has a geographic distribution that is restricted to western Ireland.     

Get up early: Revealing behavioral responses of sandeel to ocean warming using commercial catch data

1. Warming of the oceans and shifts in the timing of annual key events are likely to cause behavioral changes in species showing a high degree of site fidelity. While this is well studied in terrestrial systems, there are fewer examples from the marine environment. Sandeel (Ammodytes marinus) is a small eel‐shaped teleost fish with strong behavioral attachment to sandy habitats in which they are buried from late summer through winter. When spring arrives, the sandeel emerge to feed during the day for several of months before returning to the sand for overwintering refuge.
2. Using fisheries data from the North Sea, we investigated whether catch rates reflect the timing of emergence and if seasonal patterns are related to temperature and primary production.
3. Catch per unit effort (CPUE) was used to describe sandeel emergence. We developed indicators of the relative timing of the emergence from the winter sand refuge and the subsequent growth period. Different modeling approaches were used to investigate the relationship with bottom temperature and primary production.
4. Variation in emergence behavior was correlated with variation in sea bottom temperature. Warmer years were characterized by earlier emergence. Significant warming over the last three decades was evident in all sandeel habitats in the North Sea throughout most of their adult life history, though no net shift in the phenology of emergence was detected. Minimum temperature during spring was a better predictor of emergence behavior than, for example, degree days.
5. This study emphasizes how temperature‐induced changes in behavior may have implications for predators and fisheries of sandeel. The method can be applied to other species for which the timing of exploitation (i.e., fisheries) and species life history are well matched.

     

Potential of S-containing and P-containing complexones in improving phytoextraction of mercury by Trifolium repens L.

Mercury is a global pollutant in the modern world. There is a large number of areas in the world where mercury is present in soils in significant quantities. Remediation methods which have traditionally been proposed may pose a risk of secondary mercury contamination and/or adverse health effects for cleaners. Phytoextraction of heavy metals from the soil environment is currently considered one of the promising non-invasive methods of remediation. But this approach has limited effectiveness. Chemically induced phytoextraction can increase the efficiency of this process both by converting less bioavailable mercury compounds to bioavailable fractions in the soil and by increasing the rate of transfer of metals in plants. This paper presents the results of a screening study of various chemical amendments to enhance the phytoextraction of mercury by Trifolium repens L. The results showed good potential for the induction of phytoextraction of phosphorus(P) and sulfur (S)-containing chelates. With this study, for the first time for the phytoextraction of mercury, the monoethanolamine salt of 2,2′-(ethylenedithio) diacetic acid was used as the S-containing chelate, and the disubstituted potassium salt of 1-hydroxy ethylidene-1,1-diphosphonic acid was used as the P-containing chelate. Further attention is given to study the effect that exogenous application of phytohormones and plant growth regulators has on the efficiency of mercury absorption and physiological status of plants, which performed well in combination with a P-containing chelate.     

Interactions among Triatoma sanguisuga blood feeding sources,gut microbiota and Trypanosoma cruzi diversity in southern Louisiana

Integrating how biodiversity and infectious disease dynamics are linked at multiple levels and scales is highly challenging. Chagas disease is a vector‐borne disease, with specificities of the triatomine vectors and Trypanosoma cruzi parasite life histories resulting in a complex multihost and multistrain life cycle. Here, we tested the hypothesis that T. cruzi transmission cycles are shaped by triatomine host communities and gut microbiota composition by comparing the integrated interactions of Triatoma sanguisuga in southern Louisiana with feeding hosts, T. cruzi parasite and bacterial microbiota in two habitats. Bugs were collected from resident's houses and animal shelters and analysed for genetic structure, blood feeding sources, T. cruzi parasites, and bacterial diversity by PCR amplification of specific DNA markers followed by next‐generation sequencing, in an integrative metabarcoding approach. T. sanguisuga feeding host communities appeared opportunistic and defined by host abundance in each habitat, yielding distinct parasite transmission networks among hosts. The circulation of a large diversity of T. cruzi DTUs was also detected, with TcII and TcV detected for the first time in triatomines in the US. The bacterial microbiota was highly diverse and varied significantly according to the DTU infecting the bugs, indicating specific interactions among them in the gut. Expanding such studies to multiple habitats and additional triatomine species would be key to further refine our understanding of the complex life cycles of multihost, multistrain parasites such as T. cruzi, and may lead to improved disease control strategies.