Carriage of Staphylococcus aureus by Free-Living Wild Animals in Spain

The presence of methicillin-susceptible Staphylococcus aureus (MSSA) was analyzed in different free-living wild animals to assess the genetic diversity and predominant genotypes on each animal species. Samples were taken from the skin and/or nares, and isolates were characterized by spa typing, multilocus sequence typing (MLST) and antimicrobial susceptibility testing. The proportion of MSSA carriers were 5.00, 22.93, 19.78, and 17.67% in Eurasian griffon vulture, Iberian ibex, red deer, and wild boar, respectively (P = 0.057). A higher proportion of isolates (P = 0.000) were recovered from nasal samples (78.51%) than skin samples (21.49%), but the 9.26% of red deer and 18.25% of wild boar would have been undetected if only nasal samples had been tested. Sixty-three different spa types were identified, including 25 new spa types. The most common were t528 (43.59%) in Iberian ibex, t548 and t11212 (15.79% and 14.04%) in red deer, and t3750 (36.11%) in wild boar. By MLST, 27 STs were detected, of which 12 had not been described previously. The most frequent were ST581 for Iberian ibex (48.72%), ST425 for red deer (29.82%), and ST2328 for wild boar (42.36%). Isolates from Eurasian griffon vulture belong to ST133. Host specificity has been observed for the most frequent spa types and STs (P = 0.000). The highest resistance percentage was found against benzylpenicillin (average, 22.2%), although most of the S. aureus isolates were susceptible to all antimicrobial tested. Basically, MSSA isolates were different from those MRSA isolates previously detected in the same animal species.     

Hexose-specificity of hexokinase and ADP-dependence of pyruvate kinase play important roles in the control of monosaccharide utilization in freshly diluted boar spermatozoa

Incubation of boar sperm from fresh ejaculates in a minimal medium with 10 mM glucose induced a fast and intense activation of glycolysis, as indicated by the observed increases in the intracellular levels of glucose 6-phosphate (G 6-P) and ATP and the rate of formation of extracellular L-lactate. The effect of glucose was much more intense than that induced by fructose, sorbitol, and mannose. The greater utilization of glucose was related to a much greater sensitivity to hexokinase when compared with the other monosaccharides. Thus, the presence of 0.5 mM glucose induced total hexokinase activity in supernatants from sperm extracts of 1.7 +/- 0.1 mIU/mg protein, while the same concentration of both fructose, mannose, and sorbitol induced total hexokinase activity from 0.3 +/- 0.1 mIU/mg protein to 0.60 +/- 1 mIU/mg protein. Kinetic analysis of the total pyruvate kinase activity indicated that this activity was greatly dependent on the presence of ADP and also showed a great affinity for PEP, with an estimated Km in supernatants of 0.15-0.20 mM. Immunological location of proteins closely related to glycolysis, like GLUT-3 hexose transporter and hexokinase-I, indicated that these proteins showed the trend to be distributed around or in the cellular membranes of both head and midpiece in a grouped manner. We conclude that glycolysis is regulated by both the specific availability of a concrete sugar and the internal equilibrium between ATP and ADP levels. Furthermore, localization of proteins involved in the control of monosaccharide uptake and phosphorylation suggests that glycolysis starts at concrete points in the boar-sperm surface.     

Ceramide levels regulated by carnitine palmitoyltransferase 1C control dendritic spine maturation and cognition

The brain-specific isoform carnitine palmitoyltransferase 1C (CPT1C) has been implicated in the hypothalamic regulation of food intake and energy homeostasis. Nevertheless, its molecular function is not completely understood, and its role in other brain areas is unknown. We demonstrate that CPT1C is expressed in pyramidal neurons of the hippocampus and is located in the endoplasmic reticulum throughout the neuron, even inside dendritic spines. We used molecular, cellular, and behavioral approaches to determine CPT1C function. First, we analyzed the implication of CPT1C in ceramide metabolism. CPT1C overexpression in primary hippocampal cultured neurons increased ceramide levels, whereas in CPT1C-deficient neurons, ceramide levels were diminished. Correspondingly, CPT1C knock-out (KO) mice showed reduced ceramide levels in the hippocampus. At the cellular level, CPT1C deficiency altered dendritic spine morphology by increasing immature filopodia and reducing mature mushroom and stubby spines. Total protrusion density and spine head area in mature spines were unaffected. Treatment of cultured neurons with exogenous ceramide reverted the KO phenotype, as did ectopic overexpression of CPT1C, indicating that CPT1C regulation of spine maturation is mediated by ceramide. To study the repercussions of the KO phenotype on cognition, we performed the hippocampus-dependent Morris water maze test on mice. Results show that CPT1C deficiency strongly impairs spatial learning. All of these results demonstrate that CPT1C regulates the levels of ceramide in the endoplasmic reticulum of hippocampal neurons, and this is a relevant mechanism for the correct maturation of dendritic spines and for proper spatial learning.     

The impact of ice melting on bacterioplankton in the Arctic Ocean

Global warming and the associated ice melt are leading to an increase in the organic carbon in the Arctic Ocean. We evaluated the effects of ice melt on bacterioplankton at 21 stations in the Greenland Sea and Arctic Ocean in the summer of 2007, when a historical minimum of Arctic ice coverage was measured. Polar Surface Waters, which have a low temperature and low salinity and originate mainly from melted ice, contained a very low abundance of bacteria (7.01 × 10⁵ ± 2.20 × 10⁵ cells ml⁻¹); however, these bacteria had high specific bacterial production (2.40 ± 1.61 fmol C bac⁻¹ d⁻¹) compared to those in Atlantic Waters. Specifically, bacterioplankton in Polar Surface Waters showed a preference for utilizing carbohydrates and had significantly higher specific activities of the glycosidases assayed, i.e. β-glucosidase, xylosidase, arabinosidase and cellobiosidase. Furthermore, bacterioplankton in Polar Sea Waters showed preferential growth on some of the carbohydrates in the Biolog Ecoplate, such as d-cellobiose and N-acetyl-d-glucosamine. Our results suggest that climate change and the associated melting of Arctic ice might induce changes in bacterioplankton functional diversity by enhancing the turnover of carbohydrates. Since organic aggregates are largely composed of polysaccharides, higher solubilization of aggregates might modify the carbon cycle, weaken the biological pump and have biogeochemical and ecological implications for the future Arctic Ocean.     

Cerebral ischaemia and matrix metalloproteinase‐9 modulate the angiogenic function of early and late outgrowth endothelial progenitor cells

The enhancement of endogenous angiogenesis after stroke will be critical in neurorepair therapies where endothelial progenitor cells (EPCs) might be key players. Our aim was to determine the influence of cerebral ischaemia and the role of matrix metalloproteinase-9 (MMP-9) on the angiogenic function of EPCs. Permanent focal cerebral ischaemia was induced by middle cerebral artery (MCA) occlusion in MMP-9/knockout (MMP-9/KO) and wild-type (WT) mice. EPCs were obtained for cell counting after ischaemia (6 and 24 hrs) and in control animals. Matrigel™ assays and time-lapse imaging were conducted to monitor angiogenic function of WT and MMP9-deficient EPCs or after treatment with MMP-9 inhibitors. Focal cerebral ischaemia increased the number of early EPCs, while MMP-9 deficiency decreased their number in non-ischaemic mice and delayed their release after ischaemia. Late outgrowth endothelial cells (OECs) from ischaemic mice shaped more vessel structures than controls, while MMP-9 deficiency reduced the angiogenic abilities of OECs to form vascular networks, in vitro. Treatment with the MMP inhibitor GM6001 and the specific MMP-9 inhibitor I also decreased the number of vessel structures shaped by both human and mouse WT OECs, while exogenous MMP-9 could not revert the impaired angiogenic function in MMP-9/KO OECs. Finally, time-lapse imaging showed that the extension of vascular networks was influenced by cerebral ischaemia and MMP-9 deficiency early during the vascular network formation followed by a dynamic vessel remodelling. We conclude that focal cerebral ischaemia triggers the angiogenic responses of EPCs, while MMP-9 plays a key role in the formation of vascular networks by EPCs.     

Secretin is not necessary for exocrine pancreatic development and growth in mice

Adaptive exocrine pancreatic growth is mediated primarily by dietary protein and the gastrointestinal hormone cholecystokinin (CCK). Feeding trypsin inhibitors such as camostat (FOY-305) is known to induce CCK release and stimulate pancreatic growth. However, camostat has also been reported to stimulate secretin release and, because secretin often potentiates the action of CCK, it could participate in the growth response. Our aim was to test the role of secretin in pancreatic development and adaptive growth through the use of C57BL/6 mice with genetic deletion of secretin or secretin receptor. The lack of secretin in the intestine or the secretin receptor in the pancreas was confirmed by RT-PCR. Other related components, such as vasoactive intestinal polypeptide (VIP) receptors (VPAC(1) and VPAC(2)), were not affected. Secretin increased cAMP levels in acini from wild-type (WT) mice but had no effect on acini from secretin receptor-deleted mice, whereas VIP and forskolin still induced a normal response. Secretin in vivo failed to induce fluid secretion in receptor-deficient mice. The pancreas of secretin or secretin receptor-deficient mice was of normal size and histology, indicating that secretin is not necessary for normal pancreatic differentiation or maintenance. When WT mice were fed 0.1% camostat in powdered chow, the pancreas doubled in size in 1 wk, accompanied by parallel increases in protein and DNA. Camostat-fed littermate secretin and secretin receptor-deficient mice had similar pancreatic mass to WT mice. These results indicate that secretin is not required for normal pancreatic development or adaptive growth mediated by CCK.     

Evaluación de un programa de intervención en residencias geriátricas para reducir la frecuentación hospitalaria

Objectives

This study describes the outcomes of an intervention program in Nursing Homes and their effects on emergency room attendance, hospital admissions, and pharmaceutical expenditure.

Material and methods

This involved non-randomised community intervention in Nursing Homes with a control group. The program was implemented gradually from 2007 to 2009 in 10 Nursing Homes (857 beds) which participated voluntarily. The control group consisted of 14 Nursing homes (1,200 beds), which refused to participate or were not assigned to our Primary Care centres. Intervention consisted of comprehensive geriatric assessment and follow-up visits by trained personnel, review and adjustment of drug treatment, case management and staff training.

Results

In the Nursing Homes where the program was carried out, emergency room attendance decreased from 1165‰ (95%CI 1100-1240]) in 2006 to 674‰ (95%CI 620-730) in 2009, while in the control group it increased from 1071 (95%CI 1020-1130) to 1246‰ (95%CI 1190-1310). The hospital admissions also decreased from 48.4% (95%CI 45-52) in 2006 to 32.1% (95%CI 29-35) in 2009, while in the control group increased from 43.5% (95%CI 41-46) to 55.8% (95%CI 53-59). There was also a 9% reduction in pharmacy cost compared with an increase of 11.9% in the control group.

Conclusions

The intervention has proved effective at reducing hospital admissions and emergency room attendance in institutionalised patients, thereby streamlining pharmacy costs.     

Exploring the risks of a putative transmission of BSE to new species

The prion responsible for the Bovine Spongiform Encephalopathy (BSE) shows unique features when compared with other prions. One of these features is its ability to infect almost all experimentally tested animal models. In the paper published in The Journal of Neuroscience¹ we describe a series of experiments directed toward elucidating which would be the in vivo behavior of BSE if it would infect dogs and rabbits, two alleged prion resistant species. Protein misfolding cyclic amplification (PMCA) was used to generate canidae and leporidae in vitro adapted BSE prions. A characterization of their in vivo pathobiological properties showed that BSE prions were capable not only of adapting to new species but they maintained, in the case of rabbits, their ability to infect transgenic mice expressing human PrP. The remarkable adaptation ability of certain prions implies that any new host species could lead to the emergence of new infectious agents with unpredictable transmission potential. Our results suggest that caution must be taken when considering the use of any mammal-derived protein in feedstuffs.     

siRNA enrichment in Argonaute 2-depleted Blattella germanica

BackgroundRNA interference (RNAi) is a cellular mechanism used to fight various threats, including transposons, aberrant RNAs, and some types of viruses. This mechanism relies on the detection of dsRNA molecules, which through a pathway involving Dicer-2 (Dcr-2) and Argonaute 2 (AGO2), produces small interfering RNAs (siRNAs) that bind to the complementary RNAs triggering their degradation.MethodsUsing the cockroach Blattella germanica as a model, we examined AGO2 activity by depleting its mRNA using RNAi and analyzing the phenotypes produced.ResultsDepleting AGO2 expression had no remarkable effect on nymphal development or reproduction. dsRNA treatment triggered an immediate and transitory increase in AGO2 expression, independently of Dcr-2 action. In addition, we analyzed the siRNAs generated after injecting a heterologous dsRNA in control and AGO2-depleted animals. The results revealed that obtained siRNAs mapped non-uniformly along the dsRNA sequence. In AGO2-depleted animals, the proportion of 22 nucleotide reads was higher and accumulations of reads appeared in areas less well-represented in the controls. We also detected a preference for cytosine as the first nucleotide in controls that was significantly attenuated in AGO2-depleted individuals.Conclusions/general significanceThe siRNAs produced from a dsRNA mapped heterogeneously along the length of the dsRNA and this arrangement depends on the dsRNA sequence. AGO2 exerts its role as nuclease on the siRNA duplexes independently of its action on the corresponding mRNA. This study sheds light on an extremely useful process for reverse genetics in laboratories, in addition to the design of more effective, specific, and eco-friendly pest-control strategies.     

Auditing the management of vaccine-preventable disease outbreaks: the need for a tool

Public health activities, especially infectious disease control, depend on effective teamwork. We present the results of a pilot audit questionnaire aimed at assessing the quality of public health services in the management of VPD outbreaks. Audit questionnaire with three main areas indicators (structure, process and results) was developed. Guidelines were set and each indicator was assessed by three auditors. Differences in indicator scores according to median size of outbreaks were determined by ANOVA (significance at p≤0.05). Of 154 outbreaks; eighteen indicators had a satisfactory mean score, indicator “updated guidelines” and “timely reporting” had a poor mean score (2.84±106 and 2.44±1.67, respectively). Statistically significant differences were found according to outbreak size, in the indicators “availability of guidelines/protocol updated less than 3 years ago” (p = 0.03) and “days needed for outbreak control” (p = 0.04). Improving availability of updated guidelines, enhancing timely reporting and adequate recording of control procedures taken is needed to allow for management assessment and improvement.