Effect of salicylate stress on the hypersensitive reaction of asparagus bean to tobacco necrosis virus

Treatments of primary leaves of asparagus bean (Vigna sesquipedalis Fruhw.) with salicylate had different effects on resistance to local lesion development caused by tobacco necrosis virus (TNV), depending upon the concentration used for treatment. At 1 m , salicylate slightly reduced lesion size but not virus accumulation, while at 3 m it significantly decreased lesion size and virus accumulation. Treatments with 5 m solutions appreciably increased both parameters, but also damaged the leaf tissue.The hypersensitive reaction of the leaves to virus inoculation was accompanied by the accumulation of five host-coded protein bands (VS₀to VS₄). However, three (or more) days after treatment with salicylate at any concentration between 1 and 5 m only one band accumulated and this band appeared to correspond to VS₁. This finding clearly questions the role of the VS₁ protein in limiting the spread and multiplication of TNV.The leaves responded rapidly to treatment with salicylate with stomatal closure, increased K⁺ leakage and ethylene production. These responses are generally considered to be general reactions to stress. None of them however, was correlated with any of the observed changes in TNV infection.     

Molecular evidence of Leishmania spp. in spider monkeys (Ateles geoffroyi) from The Tuxtlas Biosphere Reserve,Veracruz, Mexico

Veterinary Research Communications - The black-handed spider monkey (Ateles geoffroyi) is a platyrrhine primate distributed in southern Mexico, Central America, and part of South America. Two...     

Antiadhesion and antibiofilm activities of high molecular weight coffee components against Streptococcus mutans

In previous studies we demonstrated that green and roasted coffee contains low molecular weight (LMW) compounds capable of inhibiting the ability of Streptococcus mutans, the major causative agent of human dental caries, to adhere to hydroxyapatite (HA) beads. This study addressed the ability of the whole high molecular weight coffee fraction (cHMW) and of its melanoidin and non-melanoidin components (GFC1-5), applied at concentrations that occur in coffee beverages, to (i) inhibit S. mutans growth; (ii) affect S. mutans sucrose-dependent adhesion to and detachment from saliva-coated HA beads (sHA); and (iii) inhibit biofilm development on microtiter plates. The results indicated that only cHMW is endowed with antimicrobial activity. The cHMW fraction and each of the five GFC components inhibited S. mutans adhesion, the strongest effect being exerted by cHMW (91%) and GFC1 (88%). S. mutans detachment from sHA was four times greater (～20%) with cHMW and the GFC1 and GFC4 melanoidins than with controls. Finally, biofilm production by S. mutans was completely abolished by cHMW and was reduced by 20% by the melanoidin components GFC2 and GFC4 and by the non-melanoidin component GFC5 compared with controls. Altogether these findings show that coffee beverage contains both LMW compounds and HMW melanoidin and non-melanoidin components with a strong ability to interfere in vitro with the S. mutans traits relevant for cariogenesis.     

HPLC-DAD-ESI-MS/MS characterization of pyranoanthocyanins pigments formed in model wine

Formation of wine pyranoanthocyanins in model wine was monitored by HPLC-DAD-ESI-MS/MS, using red grape skin extracts and wine fermentation metabolites (acetaldehyde, pyruvic and acetoacetic acids, and diacetyl) and also hydroxycinnamic acids (p-coumaric, caffeic, ferulic, and sinapic acids). Pyruvic acid and acetaldehyde reacted fast, the first reaching high product yield and the second inducing mainly pigment polymerization. In contrast, acetoacetic acid and diacetyl reacted slowly with poor product yields. Hydroxycinnamic acids progressively reacted without apparent formation of polymeric pigments, the reaction rate and yield increasing as the number of hydroxy/methoxy groups did. Substituent at C-10 strongly affected the visible maximum absorbance wavelength, whereas B-ring substitution pattern or sugar acylation exerted little effect. The 10-methylpyranoanthocyanins formed from acetoacetic acid were also found as side products in the formation of 10-carboxypyranoanthocyanins. Finally, we report for the first time on UV-vis and MS spectral data of 10-acetylpyranoanthocyanins formed from diacetyl, and their occurrence in commercial red wines is suggested.     

Native maize landraces from Los Tuxtlas, Mexico show varying mycorrhizal dependency for P uptake

Different degrees of dependency on the activity of arbuscular mycorrhizal fungi (AMF) exist between native maize landraces and hybrids. In Los Tuxtlas, Mexico, the Popoluca people maintain a traditional polycultural land management with more than 15 native landraces of maize; however, it is not known whether the recent substitution of local maize for improved hybrids and fertilization has affected the integrity of the mycorrhizal symbiosis in these naturally phosphorus-poor systems. A greenhouse experiment was conducted to evaluate the response of four Popoluca maize landraces and the hybrid Texcoco to the presence of native AMF in conditions of low and medium P input (5 and 65 mg kg^?1, respectively). After 120 days in both P treatments, the native landraces Black and Yellow presented higher colonization and had acquired more P in their shoot biomass than the hybrid. The moderate fertilization did not appear to have affected the integrity of the mycorrhizal symbiosis, since all of the maize types presented a positive mycorrhizal dependency (2–14 %). Under low P conditions, the Texcoco hybrid maize presented one of the highest mycorrhizal dependencies; however, unlike the local landraces, this was not reflected in a higher tissue P concentration. The results obtained indicate that the native maize Black was the best at capturing symbiotic and direct P, which makes this landrace an important genetic and cultural heritage for the Popoluca and for the world.     

Dissolution behavior of soy proteins and effect of initial concentration

The solution concentration profiles of soy protein and its components, glycinin and beta-conglycinin, as a function of pH and initial concentration have been measured. The concentration profiles generally followed a U-shaped trend with pH, with a minimum at around pH 4-5. Dissolution concentration unexpectedly increased with the initial concentration of the solution, with the increase being approximately proportional to the increase in initial concentration. The reasons for this are not clear. For the initial concentrations studied, beta-conglycinin is undersaturated between pH 5 and 7 and remains in solution, while glycinin becomes supersaturated in the same pH range and precipitates. Therefore separation of the two proteins can be achieved.     

Seroepidemiology of beef and dairy herds and fetal study of Neospora caninum in Argentina

The purpose of the present work was to study the epidemiology of Neospora caninum in beef and dairy herds in the Humid Pampas of Argentina. The seroprevalence of N. caninum was evaluated in 2414 serum samples of cows from beef and dairy farms. An indirect fluorescent antibody test (IFAT) was used to determine specific antibodies. The sera was screened at a dilution >or=1:200 and >or=1:600 in cows with reproductive disease antecedents and without them, respectively. Cows without history of reproductive diseases from nine beef and fifteen dairy farms were grouped according to the percentage (> or or 相似文献   

Effect of Stocking Density on the Growth and Survival of Spotted Sand Bass Paralabrax maculatofasciatus Larvae in a Closed Recirculating System

Abstract.— The effect on growth and survival of the initial stocking density (50, 100, 150, and 200 larvae/ L) in larval rearing of spotted sand bass was evaluated over 30 d in a closed recirculating system. Larvae were fed with rotifers, copepods, nauplii and adult Artemia , and spotted sand bass yolk-sac larvae. Water quality was monitored daily. The notochordal or standard length of sampled larvae was measured by image analysis. Specific growth rates at each density were compared by covariance analysis. Survival was estimated from day 15 to the end of the experiment, when a resistance test was used to evaluate the juvenile quality among densities. At the end of the experiment, mean standard length of larvae at lower densities was significantly larger ( P < 0.05) than at higher densities. Higher specific growth rates were found at lower densities. Significantly higher survival ( P < 0.05) was recorded for the lowest density, but the highest number of harvested fish was obtained with the highest densities (150 and 200 larvae/L). The lowest density also showed the significantly ( P < 0.05) higher survival after using a resistance test. We conclude the highest density can be used in larval rearing of spotted sand bass. However, better survival, growth, and seed quality are obtained at the lowest density. To recommend an optimal density for this specie, it is necessary to improve the water quality in the culture system and to make a cost-benefit study.     

Rough virulent strain of Brucella ovis induces pro- and anti-inflammatory cytokines in reproductive tissues in experimentally infected rams

The ovine brucellosis caused by Brucella ovis has tropism for reproductive tissues but until now the mechanism of bacterial persistence is not understood. Cytokine expression profiles were studied for 8 months in rams after being experimentally infected with the rough virulent strain of B. ovis (R-B. ovis) to study the pathogenesis of B. ovis and immune mechanism possibly associated to bacteria tropism and persistence. The messenger RNA (mRNA) expression levels of interleukin-1α (IL-1α), IL-1β, IL-6, IL-10, IL-12, interferon-γ (INF-γ) and tumour necrosis factor-α (TNF-α) cytokines were quantified by real-time quantitative RT-PCR (qRT-PCR) in reproductive tissues (epididymus, testicles, ampolae, vesicular glands and bulbourethral glands), and non-reproductive (liver, spleen and kidneys) tissues at 30, 60, 120 and 240 days post infection (dpi). During the acute phase of infection at 30 dpi, the host immune response was most notable demonstrating an up-regulation of several cytokines in reproductive tissues, including the epididymus (IL-6, IL-1β and IL-1α), testicles (INF-γ and IL-12), bulbourethral glands (IL-6 and TNF-α) and ampolae (INF-γ, IL-10, IL-1β and IL-1α). During the development of infection, cytokine gene expression levels decreased, providing evidence of immunosuppression and evidence of immune evasion that favoured persistence of chronic R-B. ovis infection. During the chronic phase of R-B. ovis infection (120 and 240 dpi), cytokine production was down-regulated in the epididymus (IL-1β and IL-1α), testicles (INF-γ and IL-12), and ampolae (INF-γ, IL-10, IL-1β and IL-1α), with the exception of the bulbourethral glands (IL-6 and TNF-α) and epididymus (IL-6); in these tissues, R-B. ovis infection resulted in up-regulation of the pro-inflammatory cytokine IL-6. Herein, we report cytokine expression profiles in tissues of rams experimentally infected with the rough strain of B. ovis, which are associated with bacterial persistence and macrophage activation.