Influence of different periods of pre-slaughter fasting on microbiological quality of bullfrog carcasses (Lithobates catesbeianus) / [Influência de diferentes períodos de jejum pré-abate na qualidade microbiológica de carcaças de rã-touro (Lithobates catesbeianus)]

The aim of this study was to evaluate the influence of different periods of pre-slaughter fasting (F1: 2 to 24 hours and F2: 48 to 72 hours) on the counts of hygiene indicator microorganisms and the presence of Salmonella spp. in carcasses of bullfrogs. Two different stages of the slaughter process were analyzed: after bleeding (A) and after the final carcasses cleaning (B). Samples from each fasting period were analyzed to count hygiene indicator microorganisms (n=30) and Salmonella spp. (n=140). For aerobic mesophilic microorganisms, the variation in fasting periods caused a reduction of 0.69 log10 CFU / g (P<0.05) in F2 when compared to F1 at point B of the slaughter. Coliforms at 35º C and Escherichia coli showed no differences (P >0.05) between the fasting analyzed periods. Considering the presence of E. coli, it was observed that F2 resulted in a reduction of 30% (P<0.05) positivity on point B. For Salmonella spp., the results showed that F2 contributed to an 11.5% reduction in the presence of this bacteria at point B. (P<0.05). Therefore, it is concluded that 48 to 72 hours of pre-slaughter fasting resulted in a positive impact on the microbiological quality of bullfrog carcasses.(AU)

O objetivo deste estudo foi avaliar a influência de diferentes períodos de jejum pré-abate (F1: duas a 24 horas e F2: 48 a 72 horas) nas contagens de micro-organismos indicadores de higiene e na presença de Salmonella spp. em carcaças de rãs-touro. Foram analisadas duas etapas do processo de abate: após a sangria (A) e após a toalete final da carcaça (B). As amostras de cada período de jejum foram utilizadas para contagem de indicadores de higiene (n = 30) e Salmonella spp. (n = 140). Para aeróbios mesófilos, a variação no tempo de jejum causou uma redução de 0,69 log10 UFC/g (P<0,05) em F2 quando comparado a F1 na etapa B do abate. Os coliformes a 35ºC e Escherichia coli não apresentaram diferenças (P>0,05) entre os dois períodos de jejum analisados. Considerando a presença de E. coli, F2 resultou em uma redução de 30% (P<0,05) de positividade na etapa B. Para Salmonella spp., os resultados mostraram que F2 contribuiu para uma redução de 11,5% na presença desse micro-organismo na etapa B. Portanto, conclui-se que 48 a 72 horas de jejum pré-abate tiveram um impacto positivo na qualidade microbiológica das carcaças de rã-touro.(AU)

Validation of an in vitro system to trigger changes in the gene expression of effectors of Sclerotinia sclerotiorum.

AIMS: Sclerotinia sclerotiorum, the causal agent of white mold, can infect several host species, including economically important crops. In this study, we propose and validate a new in vitro system able to mimic the conditions of interaction with the host and promote the induction of S. sclerotiorum effectors. METHODS AND RESULTS: For culture media production, we selected three plant species, common bean (Phaseolus vulgaris L, cv. Requinte.), maize (Zea mays, cv. BRS1030) and beggarticks (Bidens pilosa). To validate this system as an in vitro inducer of effectors, the qRT-PCR technique was used to investigate the expression profile of some S. sclerotiorum effector genes in each growth medium at different times after inoculation. CONCLUSION: The results obtained in this study provide a validation of a new method to study S. sclerotiorum during mimetic interaction with different hosts. Although leaf extract does not fully represent the plant environment, the presence of plant components in the culture medium seems to induce effector genes, mimicking in planta conditions. The use of MEVM is simpler than in planta growth, bypasses problems such as the amount of mycelium produced, as well as contamination of host cells during transcriptomic and proteomic analyses. SIGNIFICANCE AND IMPACT OF THE STUDY: We have devised MEVM media as a model mimicking the interaction of S. sclerotiorum and its hosts and used it to evaluate in vitro expression of effectors normally expressed only in planta.

Fusion of plectasin derivative NZ2114 with hydrophilic random coil polypeptide: Recombinant production in Pichia pastoris and antimicrobial activity against clinical strain MRSA.

One of the roadblocks towards the practical use of antimicrobial peptides for medical use is their relatively high cost when synthesized chemically. Effective recombinant production has only been successful in some cases, such as the previously reported production in Pichia pastoris of the antimicrobial plectasin derivative peptide NZ2114. The same production host has also been used extensively to produce so-called protein-polymers: sequences that consist of repetitions of simple amino acid motifs found in structural proteins such as collagen and elastin, and that can be designed to self-assemble in micelles, fibers and hydrogels. With the eventual goal of producing recombinant biomaterials such as antimicrobial protein polymer, we here explore the secreted production in Pichia pastoris of a fusion of NZ2114 with a hydrophilic random coil protein polymer CP4 . The intact NZ2114-CP4 fusion copolymer was produced with a yield of purified protein on the order of 1 g.L-1 supernatant. We find that purified NZ2114-CP4 has an activity against clinical strain MRSA, but very much lower than activity of chemically synthesized NZ2114. We conclude that possibly, the activity of NZ2114 is impaired by the C-terminal attachment to the protein polymer chain, but other reasons for the low activity cannot yet be excluded either. This article is protected by copyright. All rights reserved.

Similar hypotensive responses to resistance exercise with and without blood flow restriction.

Low intensity resistance exercise (RE) with blood flow restriction (BFR) has gained attention in the literature due to the beneficial effects on functional and morphological variables, similar to those observed during traditional RE without BFR, while the effects of BFR on post-exercise hypotension remain unclear. The aim of the present study was to compare the blood pressure (BP) response of trained normotensive individuals to RE with and without BFR. In this cross-over randomized trial, eight male subjects (23.8 ± 4 years, 74 ± 3 kg, 174 ± 4 cm) completed two exercise protocols: traditional RE (3 x 10 repetitions at 70% one-repetition maximum [1-RM]) and low intensity RE (3 x 15 repetitions at 20% 1-RM) with BFR. Blood pressure measurements were performed after 15 min of seated rest (0), immediately after and 10 min, 20 min, 30 min, 40 min, 50 min and 60 min after the experimental sessions. Similar hypotensive effects for systolic BP (SBP) were observed for both protocols (P < 0.05) after exercise, with no differences between groups (P > 0.05) and no statistically significant difference for diastolic BP (P > 0.05). These results suggest that in normotensive trained individuals, both traditional RE and RE with BFR induce hypotension for SBP, which is important to prevent cardiovascular disturbances.

Proregion of Acanthoscelides obtectus cysteine proteinase: a novel peptide with enhanced selectivity toward endogenous enzymes.

Acanthoscelides obtectus is a devastating storage insect pest capable of causing severe bean crop losses. In order to maintain their own development, insect pest larvae feed continuously, synthesizing efficient digestive enzymes. Among them, cysteine proteinases (CPs) are commonly produced as inactive precursors (procysteines), requiring a cleavage of the peptide proregion to become active. The proregion fits tightly into the active site of procysteines, efficiently preventing their activity. In this report, a CP cDNA (cpao) was isolated from A. obtectus midgut larvae. In silico studies indicated that the complete CP sequence contains a hydrophobic signal peptide, a prodomain and a conserved catalytic region. Moreover, the encoding cDNA contains 963bp translating into a 321 residue protein, CPAo, which was expressed in E. coli, fused with thioredoxin. Enzymatic assays using the recombinant protein revealed that the enzyme was catalytically active, being able to cleave the synthetic substrate Z-Phe-Arg-7-AMC. Additionally, this report also focuses the cpao propeptide (PCPAo) subcloning and expression. The expressed propeptide efficiently inhibited CPAo, as well as digestive CP of other bean bruchids. Little or no activity was found against proteolytic enzymes of two other coleopterans: Rhyzopertha dominica and Anthonomus grandis. The data reported here indicate the possibility of endogenous propeptides as a novel strategy on bruchids control, which could be applicable to bean improvement programs.

Scorpions from Mata do Buraquinho, João Pessoa, Paraíba, Brazil, with ecological notes on a population of Ananteris mauryi Lourenço (Scorpiones, Buthidae)

Four species of scorpions (Ananteris mauryi Lourenço, 1982, Tityus neglectus Mello-Leitão, 1932, T. pusillus Pocock, 1893 and T. stigmurus (Thorell, 1876)) were collected in the "Mata do Buraquinho", João Pessoa, state of Paraíba, Brazil. Aspects of biology for A. mauryi and new records on the geographic distribution of other species were annotated. Notes on the abundance and sex ratio on A. mauryi, the most abundant species in the area, are presented and discussed.

Influence of pH on the toxicity and survival of total cells and spores of Bacillus thuringiensis.

B. thuringiensis (Bt) is one of the most important microorganism among those studied because of their entomopathogenic potential against insect plagues and vectors. In this work, the pathogenicity and survival of total cells and spores of three autochthonous strains of B. thuringiensis isolated from Argentine soils (A61, A27 and A68) and the commercial strain HD-1 were studied at different ion hidrogen concentrations (pH = 4.4; 5.4; 7.4; 8.4; 9.4 and 10.4) under laboratory conditions. The greatest antimicrobial effect on the number of spores and total cells was observed at pH 4.4 with a great decrease after 72 hours' growth. Comparing the survival percentage of total cells and spores; pH 5.4 was the one which allowed the higher relative tolerance (survival) among the studied strains. No decrease in pathogenicity was observed in the investigated serotypes at different pHs in bioassays against Cydia pomonella. Two soil strains of Bt (A61/A27) and the Bt (HD-1) of commercial origin caused the highest mortality of the target insect. The sotto serotype (A68), however, did not produce this effect.

Influence of pH on the toxicity and survival of total cells and spores of Bacillus thuringiensis

Entre los grupos de microorganismos que se estudian por su potencial entomopatógeno, B. thuringiensis (Bt) es sin lugar a dudas la bacteria de mayor importancia en el control de insectos, plagas y vectores. En este trabajo se estudió la patogenicidad y sobrevivencia de células totales y de esporas de tres cepas de B. thuringiensis autóctonas de suelos argentinos (A61, A27 y A68) y una cepa comercial HD-1, a distintas concentraciones de ión hidrógeno (pH=4,4; 5,4;7,4; 8,4; 9,4 y 10,4), bajo condiciones de laboratorio. No se observó disminución de la toxicidad de las cepas desarrolladas a distintos valores de pH en bioensayos contra Cydia pomonella. El mayor efecto antimicrobiano sobre el número de esporas y células totales se detectó a pH 4,4. El pH 5,4 fue el que permitió un mayor índice de sobrevivencia en los serotipos investigados. Tres cepas de Bt (A61,A27,HD-1) mostraron alta toxicidad contra C. pomonella. El serotipo sotto, sin embargo, no produjo ese efecto

Influence of pH on the toxicity and survival of total cells and spores of Bacillus thuringiensis

Entre los grupos de microorganismos que se estudian por su potencial entomopatógeno, B. thuringiensis (Bt) es sin lugar a dudas la bacteria de mayor importancia en el control de insectos, plagas y vectores. En este trabajo se estudió la patogenicidad y sobrevivencia de células totales y de esporas de tres cepas de B. thuringiensis autóctonas de suelos argentinos (A61, A27 y A68) y una cepa comercial HD-1, a distintas concentraciones de ión hidrógeno (pH=4,4; 5,4;7,4; 8,4; 9,4 y 10,4), bajo condiciones de laboratorio. No se observó disminución de la toxicidad de las cepas desarrolladas a distintos valores de pH en bioensayos contra Cydia pomonella. El mayor efecto antimicrobiano sobre el número de esporas y células totales se detectó a pH 4,4. El pH 5,4 fue el que permitió un mayor índice de sobrevivencia en los serotipos investigados. Tres cepas de Bt (A61,A27,HD-1) mostraron alta toxicidad contra C. pomonella. El serotipo sotto, sin embargo, no produjo ese efecto (AU)