Antimicrobial Resistance, Virulence Genes, and Genetic Lineages of Staphylococcus pseudintermedius in Healthy Dogs in Tunisia

Nasal swabs of 100 healthy dogs were obtained in 2011 in Tunisia and tested for Staphylococcus pseudintermedius recovery. Antimicrobial resistance profile and virulence gene content were determined. Multilocus-sequence-typing (MLST) and SmaI-pulsed-field gel electrophoresis (PFGE) were investigated. S. pseudintermedius was recovered in 55 of the 100 tested samples (55 %), and one isolate per sample was further studied. All 55 S. pseudintermedius isolates were susceptible to methicillin (MSSP) but showed resistance to the following antimicrobials (% resistant isolates/resistance gene): penicillin (56.4/blaZ), tetracycline (40/tetM), trimethoprim-sulfamethoxazole (23.7), fusidic acid (9), kanamycin (3.7/aph(3´)-Ia), erythromycin-clindamycin (1.8/erm(B)), streptomycin (1.8/ant(6)-Ia), chloramphenicol (1.8) and ciprofloxacin (1.8). The following toxin genes were identified (% of isolates): lukS/F-I (98.2), expA (5.5), se-int (98.2), sec _canine (1.8), siet (100), sea (5.5), seb (3.6), sec (10.9), sed (54.5), sei (5.5), sej (29.1), sek (3.6), ser (9.1), and hlg _v (38.2). Ten different sequence-types were detected among 11 representative MSSP isolates: ST20, ST44, ST69, ST70, ST78, ST100, ST108, ST160, ST161, and ST162, the last three ones revealing novel alleles or allele combinations. Eleven different PFGE-patterns were identified in these isolates. The nares of healthy dogs could be a reservoir of antimicrobial resistant and virulent MSSP, highlighting the presence of the recently described exfoliating gene expA and several enterotoxin genes.     

Feeding the Probiotic Enterococcus faecium Strain NCIMB 10415 to Piglets Specifically Reduces the Number of Escherichia coli Pathotypes That Adhere to the Gut Mucosa

Feed supplementation with the probiotic Enterococcus faecium for piglets has been found to reduce pathogenic gut microorganisms. Since Escherichia coli is among the most important pathogens in pig production, we performed comprehensive analyses to gain further insight into the influence of E. faecium NCIMB 10415 on porcine intestinal E. coli. A total of 1,436 E. coli strains were isolated from three intestinal habitats (mucosa, digesta, and feces) of probiotic-supplemented and nonsupplemented (control) piglets. E. coli bacteria were characterized via pulsed-field gel electrophoresis (PFGE) for clonal analysis. The high diversity of E. coli was reflected by 168 clones. Multilocus sequence typing (MLST) was used to determine the phylogenetic backgrounds, revealing 79 sequence types (STs). Pathotypes of E. coli were further defined using multiplex PCR for virulence-associated genes. While these analyses discerned only a few significant differences in the E. coli population between the feeding groups, analyses distinguishing clones that were uniquely isolated in either the probiotic group only, the control group only, or both groups (shared group) revealed clear effects at the habitat level. Interestingly, extraintestinal pathogenic E. coli (ExPEC)-typical clones adhering to the mucosa were significantly reduced in the probiotic group. Our data show a minor influence of E. faecium on the overall population of E. coli in healthy piglets. In contrast, this probiotic has a profound effect on mucosa-adherent E. coli. This finding further substantiates a specific effect of E. faecium strain NCIMB 10415 in piglets against pathogenic E. coli in the intestine. In addition, these data question the relevance of data based on sampling fecal E. coli only.     

Temperature- and Salinity-Decoupled Overproduction of Hydroxyectoine by Chromohalobacter salexigens

Hydroxyectoine overproduction by the natural producer Chromohalobacter salexigens is presented in this study. Genetically engineered strains were constructed that at low salinity coexpressed, in a vector derived from a native plasmid, the ectoine (ectABC) and hydroxyectoine (ectD) genes under the control of the ectA promoter, in a temperature-independent manner. Hydroxyectoine production was further improved by increasing the copies of ectD and using a C. salexigens genetic background unable to synthesize ectoines.     

K+ and Na+ Conduction in Selective and Nonselective Ion Channels Via Molecular Dynamics Simulations

Generations of scientists have been captivated by ion channels and how they control the workings of the cell by admitting ions from one side of the cell membrane to the other. Elucidating the molecular determinants of ion conduction and selectivity are two of the most fundamental issues in the field of biophysics. Combined with ongoing progress in structural studies, modeling and simulation have been an integral part of the development of the field. As of this writing, the relentless growth in computational power, the development of new algorithms to tackle the so-called rare events, improved force-field parameters, and the concomitant increasing availability of membrane protein structures, allow simulations to contribute even further, providing more-complete models of ion conduction and selectivity in ion channels. In this report, we give an overview of the recent progress made by simulation studies on the understanding of ion permeation in selective and nonselective ion channels.     

Bitrophic toxicity of Cry1Ac to Cycloneda sanguinea,a predator in Brazilian cotton

Insect predators are exposed to the Cry1Ac toxin in Bt cotton fields through several pathways. In this study, we investigated the effects of activated Cry1Ac added to a diet on Cycloneda sanguinea (L.) (Coleoptera: Coccinellidae), which is one of the main predators of non‐target pests in Brazilian cotton. Direct bitrophic exposure of C. sanguinea to Cry1Ac was done by feeding beetles with Aphis gossypii (Glover) (Hemiptera: Aphidae) sprayed with 500 μg per ml Cry1Ac solution. Larval and pupal survival, development time, aphid consumption, and adult longevity were recorded daily. Couples within the same experimental treatment were paired and numbers of eggs laid and hatched per female were recorded daily. Net replacement rate was calculated for each female. During development, a C. sanguinea larva consumed on average 1.8 μg of activated Cry1Ac. No significant differences due to Cry1Ac were observed for any of the response variables, except aphid consumption. Larvae receiving Cry1Ac consumed more aphids than larvae receiving distilled water alone. Additional statistical analyses were conducted to evaluate independence of responses, and for the independent responses, a simple meta‐analysis was conducted to test the null hypothesis that all responses were zero. Nearly all of the response variables were statistically independent. Two pairs of responses were not independent, but the associated multivariate tests were not significant. The meta‐analysis suggested that all effects were not different from random variation around zero and no cumulative effects could be detected. Our results indicated that bitrophic exposure to activated Cry1Ac is likely to have little or no adverse ecological effect on C. sanguinea.     

Palynological evaluation of selected honeys from Romania

Fifty-four honey samples collected over two consecutive harvest seasons (2009–2010) from different floristic areas of Romania were analysed. A melissopalynological analysis including qualitative and quantitative analyses was carried out in order to identify the principal pollen types in Romanian honeys and therefore, the important plants exploited by Apis mellifera in this country. Seventy-seven pollen types from 35 botanical families were identified. The main pollen forms were: Brassica napus-type, Tilia, Helianthus annuus, Robinia pseudoacacia, Prunus, Castanea sativa, Fragaria-type and Plantago-type. Honey samples were classified as: acacia honey (Robinia pseudoacacia), lime honey (Tilia), rape honey (Brassica napus-type), sunflower honey (Helianthus annuus), cherry honey (Prunus). Three of them were honeydew honeys whereas the others were all polyfloral. The results from this study can be used as a palynological baseline data of Romanian artisanal honeys.     

Pollen production in the Poaceae family

Total pollen production per inflorescence was studied in the most important species of the Poaceae family in the city of Córdoba in order to further our knowledge of the partial contribution of each species of this family to the total amount of pollen released into the atmosphere.

The contribution of grasses in a given area was estimated by counting the number of inflorescences in an area of one square meter. Four different representative areas of the city were selected. The number of pollen grains per anther and flowers per inflorescence was also estimated in order to obtain total pollen production per inflorescence.

Pollen production per inflorescence ranged from 14,500 to more than 22,000,000 pollen grains, the amount being clearly higher in the perennial species. Pollen production per square meter was higher in the mountains near the city and lower in areas of abandoned crops.

Only a few species are responsible for the majority of pollen produced. A phenological study is necessary in order to determine the temporal distribution of this pollen production and subsequent shedding.     

Pollen biology in four Mediterranean Quercus species

Potential pollen production, viability and germination were studied in the most important species of Quercus in the mountains of Córdoba to determine the contribution of each species to the total amount of airborne pollen. The results were compared over two consecutive years with different rainfall patterns. The viability of pollen grains was determined at anther opening, and during the pollination period, in order to determine potential pollination capacity. Results indicated that there were differences in the number of pollen grains produced by stamen in the four species. Equally, there were differences in the number of flowers among the species, being Q. suber the species with higher number of catkins groups and flowers per individual tree. Total pollen production per tree can be summarized in the following proportion: 1: 3: 3: 6 (Q. coccifera, Q. ilex ssp. ballota, Q. faginea and Q. suber). Potential pollen viability was estimated using the Fluorochromatic Reaction (FCR) and a germination assay. The results have shown that Quercus potential pollen viability is high and declines slowly with time. Q. coccifera was the species with the highest percentage of germination, with Q. suber being the lowest.     

Prolactin administration during early postnatal life decreases hippocampal and olfactory bulb neurogenesis and results in depressive-like behavior in adulthood

Tight regulation of hormone and neurochemical milieu during developmental periods is critical for adequate physiological functions. For instance, activation of peptide systems during early life stress induces morphological changes in the brain resulting in depression and anxiety disorders. Prolactin (PRL) exerts different actions within the brain; it regulates neurogenesis and modulates neuroendocrine functions in the adult. However, PRL effects during early postnatal life are hardly known. Therefore, we examined whether neonatal administration of PRL influences cell survival in the hippocampal dentate gyrus (DG) and in the olfactory bulb (OB) and whether such influence results in behavioral consequences in adulthood. PRL-treated rat pups (13 mg/kg; PND1 to PND14), injected with BrdU at postnatal day 5 (PND5), showed a decrease in the density of DG BrdU/DCX and BrdU/NeuN-positive cells that survive at PND15. Similarly, PRL treatment decreased the density of BrdU + cells in the OB compared with VEH. Fluorojade B analysis showed no significant changes in the amount of cell death in the DG between the groups. Postnatal PRL administration induced a passive coping strategy in the forced swimming test in male and female adult rats when compared with control and vehicle groups. Corticosterone endogenous levels at PND12 were not affected by PRL or VEH treatment. Altogether, these results suggest that opposed to its effects in the adult, postnatal PRL treatment affects neurogenesis and results in psychopathology later in life. High PRL levels, as observed in neonates under several pathological states, might contribute to detrimental effects on the developing brain.