EDTA and Taurolidine Affect Pseudomonas aeruginosa Virulence In Vitro-Impairment of Secretory Profile and Biofilm Production onto Peritoneal Dialysis Catheters

Peritoneal catheter-associated biofilm infection is reported to be the main cause of refractory peritonitis in peritoneal dialysis patients. The application of antimicrobial lock therapy, based on results on central venous catheters, may be a promising option for treatment of biofilm-harboring peritoneal catheters. This study investigated the effects of two lock solutions, EDTA and taurolidine, on an in vitro model of Pseudomonas aeruginosa biofilm-related peritoneal catheter infection. Silicone peritoneal catheters were incubated for 24 h with a bioluminescent strain of P. aeruginosa. Then, serial dilutions of taurolidine and/or EDTA were applied (for 24 h) once or twice onto the contaminated catheters, and P. aeruginosa viability/persistence were evaluated in real time up to 120 h using a Fluoroskan reader. On selected supernatants, high-performance liquid chromatography mass spectrometry (HPLC-MS) analysis was performed to measure the production of autoinducers (AI), phenazines, and pyocyianines. Taurolidine alone or in combination with EDTA caused a significant decrease of bacterial load and biofilm persistence on the contaminated catheters. The treatment did not lead to the sterilization of the devices, yet it resulted in a substantial destructuration of the catheter-associated P. aeruginosa biofilm. HPLC-MS analysis showed that the treatment of biofilm-harboring catheters with taurolidine and EDTA also affected the secretory activity of the pathogen. EDTA and taurolidine affect P. aeruginosa biofilm produced on peritoneal catheters and profoundly compromise the microbial secretory profile. Future studies are needed to establish whether such lock solutions can be used to render peritoneal catheterrelated infections more susceptible to antibiotic treatment

Tannin treated lucerne silage in dairy cow feeding

The effects of the addition of tannins to lucerne silage were investigated. At ensiling, chestnut hydrolyzable tannins were added to lucerne forage (T=tannins treated lucerne silage vs C=control lucerne silage). Fifty lactating Holstein cows, fed two diets different for lucerne silage treatment (C or T), were used in a cross-over design. In situ rumen soluble protein fraction (%CP) was higher for C (67.9 vs 59.4; P<0.01), whereas potentially rumen degradable protein (%CP) was lower (24.5 vs 32.1 for C and T; P<0.01). Intestinal rumen escape protein digestibility (%) was numerically higher for T (48.3 vs 54.3). Dry matter intake (21.5 kg/d for both diets) and milk yield (29.8 and 30.2 kg/d for C and T) were not affected by dietary treatment, whereas FCM was slightly higher for T diet (27.5 vs 27.9 kg/d for C and T; P<0.10). Adding tannins to lucerne silage is effective in shifting part of N utilization from the rumen to the intestine, leading to similar productive performance in lactating cows

Effects of constant vs variable dietary protein content on milk production and N utilization in dairy cows.

Forty-two lactating Holstein cows were divided into two groups, control (C) and test (T), and used in a cross-over design. In each group cows were also divided in three subgroups on the basis of milk yield: low (L), medium (M) and high (H). C cows were fed a diet with 15.4% CP on DM. T cows were fed three diets with the CP content (% DM) adjusted to milk yield (13.6, 15.2 and 17.2 for diets TL, TM and TH). At the highest level of production TH diet improved milk yield (kg/d) (38.9 C vs 41.0 TH) and FCM (kg/d) (39.6 C vs 40.6 TH) (P<0.05). No differences were detected for TL and TM diets compared to C. For L and H subgroups milk urea (mg/dl) was increased by the higher CP diets (28 C vs 24 TL; 30 C vs 36 TH; P<0.05). N efficiency (milk N, %N intake) was higher with lower CP diets (22 C vs 25 TL; 32 C vs 29 TH) and for increased milk yield. An adequate CP content of the diet enhances milk production in high yielding dairy cows, but an excessive amount of dietary N increases milk urea and N excretion

Comparison of lucerne silage and ventilated hay in maize silage-based rations for dairy cows for the production of milk destined for Grana cheese

Three experiments were carried out to study the effects of feeding lucerne silage (wilted to give different dry-matter (DM) contents) and ventilated hay to dairy cows on milk production, milk quality, milk-renneting properties, clostridial spore content and the quality of cheese prepared from the milk. The lucerne, cut at vegetative or early-bud stages of maturity, was harvested from alternate windrows and conserved as silage or artificially dried hay. The lucerne was wilted until it reached different DM contents of 550, 360 and 432 g kg-1 in the three experiments, harvested, chopped with a self-loading forage wagon and ensiled in low and narrow clamps made up of transferable prefabricated walls. The organic acid content, pH, yeast and mould counts of the lucerne silage suggested that there was no aerobic deterioration. In each experiment, fifty Italian Friesian lactating cows were divided into two groups and fed two maize silage-based rations for 6 weeks, which only differed in the lucerne forage [silage (S) vs. ventilated hay (H)], in a cross-over experimental design. The lucerne in the rations represented 35%, 23% and 24% of the DM of the rations for the three experiments. The microbiological profiles of the ration were influenced more by the maize silage than by the lucerne silage. Individual daily DM intakes were similar for the two treatments in Experiments 1 and 3 (on average 18.7 kg in Experiment 1 and 20.3 kg in Experiment 3) and slightly lower for S cows in comparison to H cows in Experiment 2 (18.0 vs. 19.0 kg). Milk yields of S and H cows were 21.0 and 20.8, 20.0 and 20.6 (P < 0.01), and 28.4 and 27.9 kg d-1 in Experiments 1, 2 and 3 respectively. Milk composition was similar for all the experiments for the two treatments, except that the protein content was lower and the fat content was higher in the silage treatment than in the hay. The renneting properties and microbiology of the milk were not influenced by the introduction of lucerne silage into the rations, although the season in which it was consumed had a greater effect on the microbiological content, in terms of standard bacterial counts, proteolytic, coli and lactic acid bacteria, and clostridia spores. The clostridial spore counts were always very low (< 400 per litre), thus fulfilling the requirements for top-quality milk for Grana cheese production. In the third experiment, the quality of Grana Padano cheese produced was examined, and no differences between treatments were observed after 12 months of maturation. These results show that lucerne silage can be included in the ration of dairy cows instead of ventilated lucerne hay, which is considered to be the top-quality hay available for the production of milk destined for Grana cheese, without any negative effects on milk and cheese quality

Efeito de um retrocruzamento na média e na variância de uma população de soja.

O objetivo desse trabalho foi avaliar a eficiência de um retrocruzamento para o genitor mais produtivo para a obtenção de linhagens superiores para a produção de grãos (PG) em soja, a partir de um cruzamento biparental. Foram avaliadas experimentalmente 100 progênies de cada um dos dois tipos: progênies F2:4 e progênies RC1F3, em diferentes anos e locais, utilizando o delineamento em látice simples duplicado 10x10 (quatro repetições) e parcelas lineares de 2 m espaçadas de 0,5 m, contendo 30 plantas após o desbaste

Activation of 5-hydroxytryptamine type 3 receptor-expressing c-fiber vagal afferents inhibits retrotrapezoid nucleus chemoreceptors in rats

Retrotrapezoid nucleus (RTN) chemoreceptors are regulated by inputs from the carotid bodies (CB) and from pulmonary mechanoreceptors. Here we tested whether RTN neurons are influenced by 5-hydroxytryptamine type 3 receptor-expressing C-fiber vagal afferents. in urethan-anesthetized rats, selective activation of vagal C-fiber afferents by phenylbiguanide (PBG) eliminated the phrenic nerve discharge (PND) and inhibited RTN neurons (n = 24). PBG had no inhibitory effect in vagotomized rats. Muscimol injection into the solitary tract nucleus, commissural part, reduced inhibition of PND and RTN by PBG (73%), blocked activation of PND and RTN by CB stimulation (cyanide) but had no effect on inhibition of PND and RTN by lung inflation. Bilateral injections of muscimol into interstitial solitary tract nucleus (NTS) reduced the inhibition of PND and RTN by PBG (53%), blocked the inhibitory effects of lung inflation but did not change the activation of PND and RTN neurons by CB stimulation. PBG and lung inflation activated postinspiratory neurons located within the rostral ventral respiratory group (rVRG) and inhibited inspiratory and expiratory neurons. Bilateral injections of muscimol into rVRG eliminated PND and partially decreased RTN neuron inhibition by PBG (32%). in conclusion, activation of cardiopulmonary C-fiber afferents inhibits the activity of RTN chemoreceptors. the pathway relays within a broad medial region of the NTS and involves the rVRG to a limited degree. the apnea triggered by activation of cardiopulmonary C-fiber afferents may be due in part to a reduction of the activity of RTN chemoreceptors.Univ Virginia Hlth Syst, Dept Pharmacol, Charlottesville, VA 22908 USAUniversidade Federal de São Paulo, Escola Paulista Med, Dept Physiol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Physiol, São Paulo, BrazilWeb of Scienc

Poder de discriminação de genótipos e representatividade de locais utilizados na avaliação de arroz de terras altas.

Neste trabalho foram utilizados dados do caráter produção de grãos provenientes de dezoito ensaios de Valor de Cultivo e Uso, conduzidos pelo programa de melhoramento de arroz de terras altas da Embrapa Arroz e Feijão, período-safra 2009/10. O objetivo foi identificar o local de teste que apresente, simultaneamente, maior poder de discriminação dos genótipos para esse caráter e represente mais adequadamente os demais locais de avaliação.Pôster - pós-graduação

Validação do QTL PUP1 para tolerância à deficiência de fósforo em arroz de terras altas.

O objetivo deste estudo é validar em progênies S0:2 da população CNA9/3/1 (de seleção recorrente) a presença do QTL Phosphorus uptake 1 (Pup1). Nesse sentido, foram avaliados sete marcadores moleculares codominantes e nove dominantes, específicos para esse QTL

Tolerância à deficiência de P: divergência genética em famílias da população-base CNA9.

O objetivo deste estudo foi o de caracterizar geneticamente 137 famílias S0:2 da população-base CNA9|3|1, sintetizada visando principalmente tolerância à deficiência hídrica e de P no solo.Apresentação oral - graduação

Variabilidade genética com seleção recorrente em arroz de terras altas.

O objetivo deste trabalho foi obter estimativas de parâmetros genéticos e fenotípicos entre progênies S0:2 da população CNA6 de arroz de terras altas durante quatro ciclos de seleção recorrente, visando analisar a variabilidade genética para o caráter produção de grãos (PG, em kg ha-1)