Virulence Patterns in a Murine Sepsis Model of ST131 Escherichia coli Clinical Isolates Belonging to Serotypes O25b:H4 and O16:H5 Are Associated to Specific Virotypes

Escherichia coli sequence type (ST)131 is an emerging disseminated public health threat implicated in multidrug-resistant extraintestinal infections worldwide. Although the majority of ST131 isolates belong to O25b:H4 serotype, new variants with different serotypes, STs using the discriminative multilocus sequence typing scheme of Pasteur Institute, and virulence-gene profiles (virotypes) have been reported with unknown implications on the pattern of spread, persistence and virulence. The aim of the present study was to compare virulence in a mouse subcutaneous sepsis model of representative ST131 clinical isolates belonging to 2 serotypes (O25b:H4, O16:H5) and nine virotypes and subtypes (A, B, C, D1, D2, D3, D4, D5 and E). Fourteen out of the 23 ST131 isolates tested (61%) killed 90 to 100% of mice challenged, and 18 of 23 (78%) at least 50%. Interestingly, different virulence patterns in association with virotypes were observed, from highly rapid lethality (death in less than 24 h) to low final lethality (death at 7 days) but with presence of an acute inflammation. This is the first study to assess virulence of ST131 isolates belonging to serotype O16:H5, which exhibited virotype C. In spite of their low virulence-gene score, O16:H5 isolates did not show significant differences in final lethality compared with highly virulent O25b:H4 isolates of virotypes A, B and C, but killed mice less rapidly. Significant differences were found, however, between virotypes A, B, C (final lethality ≥80% of mice challenged) and virotypes D, E. Particularly unexpected was the low lethality of the newly assigned virotype E taking into account that it exhibited high virulence-gene score, and the same clonotype H30 as highly virulent O25b:H4 isolates of virotypes A, B and C. In vivo virulence diversity reported in this study would reflect the genetic variability within ST131 clonal group evidenced by molecular typing.     

Larval width as indicator of growth rate and effect of larval classification on final body composition and flesh quality in cultured gilthead seabream (Sparus aurata,L.)

The objective of this study was evaluating the effects on the growth rate and flesh quality of separating larvae according to their larval width in cultured gilthead seabream (Sparus aurata, L.). Progeny from two broodstocks (A and B) were divided into two groups according to larval width: heads (being the larger specimens) and tails. After 18 months both groups were analysed to evaluate growth, carcass traits and proximal composition. The head specimens reached a larger size and showed a greater level of well‐being and degree of nourishment. Total body and fillet composition in general were found to be as expected for this species. Some differences were found in total body composition between head and tail specimens in both batches, and in the fillet composition in batch B (higher fat and lower moisture content in the head specimens). Sensory analyses were carried out using untrained panelists, who were unable to distinguish between the head and tail samples in batch A, whereas differences were noticeable in batch B. Samples from the head group were judged to be tastier and juicier, a consequence of their higher fat content. Hence, fish separation according to larval width is an effective tool to separate progeny into slow and fast growing groups, whereas the total body and fillet analyses and a sensory test ensure that the selection does not generate negative effects on the product quality.     

Chemical transformation,phytotoxicity and nutrient availability in progressive composting stages of wheat straw

Chemical maturity parameters in addition to plant growth limiting factors have been monitored in the course of a 2-month composting experiment. Wheat straw with 5% dry w horse manure was adjusted to C/N= 45 with urea. The pile was rotated and homogeneous samples were taken every four days. The most intense changes in straw fractions occurred in the first 20 days of composting, as suggested by wet chemical analyses, thermogravimetry and ¹³C NMR spectrometry. Nevertheless, plant response to compost application gave significant changes at between 20–60 days that were not clearly reflected by the above techniques. Glasshouse experiments with a soil treated with compost samples taken at the successive transformation stages suggested no linear correlation between composting time and the potential of compost in improving plant yield. In the samples taken after 20 days in the conditions studied, referred to as postmature composts, the ryegrass yield did not depend on most of the organic matter characteristics, but closely paralleled the concentration of available nitrogen and – to lesser extent – phosphorous in the compost. The probable immobilization of these elements in the course of composting was also suggested by plant response experiments with different doses of compost and the addition or not of mineral solution.     

A review on greywater reuse: quality,risks, barriers and global scenarios

Greywater is wastewater collected from household sources without input from toilet or commode streams. Greywater represent ca. 65% of total household wastewaters globally. Different aspects of greywater, including its production sources, its characteristics, the barriers and the global scenarios of its reuse, have been critically reviewed in this paper. Given the current projections on acute water scarcity in many regions of the world, the importance of water management cannot be overlooked and a decentralized approach, segregating wastewater streams of a household with proper sanitation is a potential option for recycling greywater. This paper aims to explore the improvements achieved in the reuse of greywater. Therefore, reutilization rates were estimated, hazards and risks associated with the use of untreated greywater were analyzed were summarized. Guidelines for greywater treatment were established and barriers for successful implementation of reuse strategies were identified. Global scenarios of successful implementations of greywater reuse were presented.

     

Prokaryotic and viral community of the sulfate-rich crust from Peñahueca ephemeral lake,an astrobiology analogue

Peñahueca is an athalassohaline hypersaline inland ephemeral lake originated under semiarid conditions in the central Iberian Peninsula (Spain). Its chemical composition makes it extreme for microbial life as well as a terrestrial analogue of other planetary environments. To investigate the persistence of microbial life associated with sulfate-rich crusts, we applied cultivation-independent methods (optical and electron microscopy, 16S rRNA gene profiling and metagenomics) to describe the prokaryotic community and its associated viruses. The diversity for Bacteria was very low and was vastly dominated by endospore formers related to Pontibacillus marinus of the Firmicutes phylum. The archaeal assemblage was more diverse and included taxa related to those normally found in hypersaline environments. Several ‘metagenome assembled genomes’ were recovered, corresponding to new species of Pontibacillus, several species from the Halobacteria and one new member of the Nanohaloarchaeota. The viral assemblage, although composed of the morphotypes typical of high salt systems, showed little similarity to previously isolated/reconstructed halophages. Several putative prophages of Pontibacillus and haloarchaeal hosts were identified. Remarkably, the Peñahueca sulfate-rich metagenome contained CRISPR-associated proteins and repetitions which were over 10-fold higher than in most hypersaline systems analysed so far.     

Circadian rhythm of lactate dehydrogenase in rat testis

Activity of total lactate dehydrogenase (LDH) and of the isozyme X (LDH X or C4) have been determined at 2 hr intervals during 24 hr cycles in testis of adult rats maintained since birth in a photoperiod of 14 hr light: 10 hr dark. LDH X activity of epididymal sections (caput, corpus and cauda) from the same animals was also determined. Total LDH and LDH X activities in testis exhibited circadian rhythms with different timing. LDH X in the three portions of epididymis showed diurnal variations similar to those in testis. Rats subjected to constant light or constant dark presented marked modifications of LDH X profiles, indicating that the photoperiod plays a synchronizer role. While total soluble proteins did not show variations in testis of rats exposed to the photoperiod, a circadian rhythm was demonstrated in animals maintained in constant light or dark.     

Clamping,bending, and twisting inter-domain motions in the misfold-recognizing portion of UDP-glucose: Glycoprotein glucosyltransferase

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