Genetic parameters for body weight in meat quail.

The aim of this study was to estimate genetic parameters for BW in meat quail at different ages. A total of 24,382 weight records from 3,652 quail, born between 2009 and 2011, were evaluated. Weekly BW was measured from hatch until 42 d of age. The genetic parameters were estimated by the restricted maximum likelihood method using a multivariate animal model. Heritability of BW ranged from 0.03 to 0.23. Genetic correlations were mainly high and positive. Selection for BW at 28 d of age yielded good indirect genetic progress in BW at 42 d of age.

Multiple antimicrobial resistance of gram-negative bacteria from natural oligotrophic lakes under distinct anthropogenic influence in a tropical region.

The aim of this study was to evaluate the resistance to ten antimicrobial agents and the presence of bla ( TEM1 ) gene of Gram-negative bacteria isolated from three natural oligotrophic lakes with varying degrees of anthropogenic influence. A total of 272 indigenous bacteria were recovered on eosin methylene blue medium; they were characterized for antimicrobial resistance and identified taxonomically by homology search and phylogenetic comparisons. Based on 16S ribosomal RNA sequences analysis, 97% of the isolates were found to be Gram-negative bacteria; they belonged to 11 different genera. Members of the genera Acinetobacter, Enterobacter, and Pseudomonas predominated. Most of the bacteria were resistant to at least one antimicrobial. The incidence of resistance to beta-lactams, chloramphenicol, and mercury was high, whereas resistance to tetracycline, aminoglycosides, and nalidixic acid was low. There was a great frequency of multiple resistances among the isolates from the three lakes, although no significant differences were found among the disturbed and reference lakes. The ampicillin resistance mechanism of 71% of the isolates was due to the gene bla ( TEM1 ). Our study suggests that multiresistant Gram-negative bacteria and the bla ( TEM1 ) gene are common in freshwater oligotrophic lakes, which are subject to different levels of anthropogenic inputs.

Surface motility and associated surfactant production in Agrobacterium vitis.

AIMS: Agrobacterium vitis is the causal agent of crown gall of grapevine. Surface motility (swarming), an important mechanism for bacterial colonization of new environments and a previously unknown behaviour of Ag. vitis, was demonstrated. METHODS: Surface motility assays were performed on half-strength potato dextrose agar (Difco) containing 0.75% agar. To test for surfactant production, a drop-collapse test was used. Quorum-sensing (QS) negative and complemented mutants were tested for swarming activity. RESULTS: Ninety-one Agrobacterium strains representing -Agrobacterium tumefaciens (17 strains), Agrobacterium rhizogenes (14 strains) and Ag. vitis (60 strains) were tested for swarming and production of surfactant. All Ag. vitis strains expressed a surface-related motility. In contrast, none of 17 strains of Ag. tumefaciens or 14 strains of Ag. rhizogenes exhibited this behaviour. Surface motility in Ag. vitis was associated with surfactant secretion; both of which are regulated by a QS system previously associated with induction of a hypersensitive response on tobacco and necrosis on grape. An aviR (belongs to luxR family) mutant was surface motility negative and did not produce surfactant. An avsI mutant (autoinducer synthase) was also surface motility negative and was complemented with an Ag. tumefaciens clone expressing avsI. CONCLUSIONS: Agrobacterium vitis is able to produce a characteristic swarming phenotype that is regulated by a complex QS system. SIGNIFICANCE AND IMPACT OF THE STUDY: Swarming activity is unique to Ag. vitis among Agrobacterium sp. and may be associated with the ability of the pathogen to colonize grapevines.

Multiple antimicrobial resistance in Enterobacteriaceae isolates from pristine freshwater.

A freshwater enterobacterial population (N = 111) was studied for antimicrobial and mercury resistance patterns, and for its possible association with biotic and abiotic factors in that environment. Conventional biochemical tests identified Klebsiella sp, Morganella sp, Serratia sp, Escherichia sp, Enterobacter sp, Edwarsiella sp, Proteus sp, Citrobacter sp, Providencia sp, and Kluyvera sp. There was no correlation between antimicrobial resistance patterns of isolates and bacterial genera, but resistance patterns varied among water samples and between seasons. Resistance to multiple antimicrobials was common (61%). The percentage of bacteria resistant to at least one antimicrobial differed between the rainy (100%) and dry seasons (89%). Resistance to beta-lactams and chloramphenicol was the most frequent and resistance to amikacin, gentamicin and kanamycin was less frequent. The main water variables examined (abiotic factors pH and temperature; biotic factor chlorophyll a concentration) did not influence antimicrobial resistance. Significant impact on freshwater enterobacteria, as evidenced by antimicrobial-multiple resistance and by the presence of bla(TEM) gene, may point to the fact that it has an important role in horizontal spread of resistance.

Relationships of feedlot performance, feeding behavior, rumen morphometrics, and carcass characteristics of Nellore cattle differing in phenotypic residual feed intake.

The objective of this study was to examine the relationship of DMI fluctuation, feedlot performance, feeding behavior, rumen morphometrics, and carcass characteristics in Nellore cattle classified by residual feed intake (RFI). One experiment was conducted in 2 consecutive years using individual pens (1.0 × 7.0 m) at the São Paulo State University feedlot, Dracena campus, Brazil. The experiment in year 1 started in June of 2012 with forty-eight 20-mo-old Nellore yearling bulls with an initial BW of 358.2 ± 19.4 kg. The experiment in year 2 started in January of 2013 with sixty 20-mo-old Nellore yearling bulls with an initial BW of 402.5 ± 33.0 kg. Experiments in years 1 and 2 lasted 94 and 84 d, respectively. All yearling bulls were categorized as high RFI (>0.5 SD above the mean, = 25), medium RFI (±0.5 SD from the mean, = 56), and low RFI (<0.5 SD below the mean, = 27). Visual appraisal to collect behavior data was made on d 40 (finishing period) of both years. Yearling bulls were harvested when average across treatment groups achieved a fat thickness of 4 mm at the 12th rib. Low-RFI yearling bulls had lower daily DMI, expressed either in kilograms ( < 0.01) or as percentage of BW ( < 0.01), and improved G:F ( < 0.01) when compared to high-RFI animals. No differences were observed ( > 0.10) for ADG, final BW, or HCW among RFI groups. Also, low-RFI yearling bulls had thinner final 12th rib ( < 0.01) and biceps femoris (P8) fat thickness ( < 0.01). Low-RFI yearling bulls were slower to consume ( = 0.03) and ruminate ( < 0.01) 1 kg of either DM or NDF. No significant ( > 0.10) RFI effect was observed for any ruminal morphometrics variables evaluated, with the exception of papillae area, in which low-RFI Nellore yearling bulls tended to have smaller ( = 0.07) papillae area than medium-RFI animals. In general, low-RFI Nellore yearling bulls consumed more particles larger than 19 and 8 mm and had a similar performance when compared to both medium- and high-RFI bulls; however, carcass fat composition was negatively impacted.

Capacity of mercury volatilization by mer (from Escherichia coli) and glutathione S-transferase (from Schistosoma mansoni) genes cloned in Escherichia coli.

A study was carried out to evaluate the capacity for mercury volatilization by genetically engineered strains that express the mer and glutathione S-transferase genes from Escherichia coli and Schistosoma mansoni, respectively. This method enabled strains containing simultaneously mer and glutathione S-transferase genes to grow in high concentrations of mercuric chloride (30 microg/ml) and to volatilize part of the mercury (248 microg/g cell dry wt.) present in the culture medium, while strains bearing only a single gene, did not have the same behavior. Up to 70% of the total mercury of bacterial volatilization occurred in the first 4 h. Although the findings were preliminary, the genetically engineered strain containing simultaneously the mer and glutathione S-transferase genes show a great potential for bioremediation. It may be used in a closed system to remove by volatilization, and recover mercury (Hg0) from contaminated effluents, such as industrial effluent, for instance.

Atividades biológicas de espécies amazônicas de Rubiaceae / Biological activities of Amazonian species of Rubiaceae

RESUMORubiaceae é uma família botânica com grande potencial químico e biológico Neste trabalho realizou-se a prospecção fitoquímica e avaliou-se as atividades citotóxica, antioxidante e antifúngica dos extratos diclorometânicos e metanólicos das folhas de Duroia saccifera, Ferdinandusa goudotiana, F. hirsuta, F. paraensis, Ferdinandusa sp., Palicourea corymbifera e P. guianensis. A avaliação da citotoxicidade foi realizada empregando-se o ensaio de toxicidade sobre Artemia salina. A atividade antifúngica foi determinada pelo método de difusão em ágar utilizando-se os fungos: Epidermophyton floccosum, Microsporum canis 32905, M. gipseum 29/00, Trichophyton mentagrophytes ATCC 9533/03, T. rubrum ATCC 28189, T. tonsurans 21/97, Cladosporium cladosporioides, C. sphaerospermum, FusariumU. 662/06, Scytalidium U. 661/06, Candida albicans ATCC 3632 e C. albicans U. 5/99. A atividade antioxidante foi determinada através dos ensaios de redução do radical livre 1,1-difenil-2-picrilhidrazila (DPPH) e de descoloração do cátion radical ácido-6-sulfônico-2,2-azinobis-3-etilbenzotiazolina (ABTS). Para o ensaio de toxicidade sobre A. salina observou-se maior toxicidade no extrato metanólico de F. goudotiana, que se mostrou tóxico até a concentração de 5 µg mL-1. A presença de princípios antifúngicos foi observada em F. hirsuta e F. paraensiscontra quatro dos fungos testados. Na avaliação da atividade antioxidante os extratos metanólicos mostraram maior atividade que os extratos diclorometânicos, sendo coincidente o resultado obtido através de ambos os métodos (redução do DPPH e descoloração do ABTS). Os resultados criam possibilidades para futuras investigações relacionadas à estrutura e atividade dos componentes de cada extrato ativo.

ABSTRACTRubiaceae is a plant family with great chemical and biological potential. In this work a phytochemical prospection was performed and it was assessed the cytotoxic, antioxidant and antifungal activities of dichloromethanic and methanolic extracts of the leaves of Duroia saccifera, Ferdinandusagoudotiana, F. hirsuta, F. paraensis, Ferdinandusa sp., Palicourea corymbifera and P. guianensis. The cytotoxicity evaluation was carried out using the test toxicity on Artemia salina. The antifungal activity was determined by agar diffusion method using fungi: Epidermophyton floccosum, Microsporum canis 32905, M. gipseum 29/00, Trichophyton mentagrophytes ATCC 9533/03, T.rubrum ATCC 28189, T. tonsurans 21/97 , Cladosporium cladosporioides, C. sphaerospermum, FusariumU. 662/06, Scytalidium U. 661/06, Candida albicans ATCC 3632 and C. albicans U. 5/99. The antioxidant activity was determined by testing the amount of free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the discoloration of the radical cation 6-sulfonic acid-2 ,2-azinobis-3-ethylbenzothiazoline (ABTS). For the toxicity test on A. salina greater toxicity in the methanol extract of F. goudotiana was observed, which proved to be toxic up to a concentration of 5 µg mL-1. The presence of antifungal principles was observed in the F. hirsuta and F. paraensis against four tested fungi. In the evaluation of the antioxidant activity, the methanol extracts showed greater activity than the dichloromethanic ones, being similar the obtained result through both methods (reduction of DDPH and ABTS decolorization) . The results create possibilities for future researches related to the structure and activity of the components of each active extract.

Exoproducts of the Escherichia coli strain H22 inhibiting some enteric pathogens both in vitro and in vivo.

AIMS: The antagonistic activity of the Escherichia coli strain H22 against enteric bacteria was studied both in vitro and in vivo. METHODS AND RESULTS: In vitro, bacterial strains belonging to seven of nine genera of the family Enterobacteriaceae (Enterobacter, Escherichia, Klebsiella, Morganella, Salmonella, Shigella and Yersinia) were inhibited by the strain H22. Six days after simultaneous oral inoculation in germ-free mice, E. coli strain H22 reduced the faecal population of Shigella flexneri 4 to undetectable levels (P < 0.05). In ex vivo assay, inhibitory zones against Sh. flexneri 4 were observed around faecal samples from mice inoculated with E. coli strain H22. The in vitro inhibition of Sh. flexneri 4 was shown to be mediated by microcin C7. In addition to microcin C7, strain H22 was shown to produce aerobactin, new variants of colicins E1 and Ib, and bacteriophage particles with morphology similar to the phages of the family Myoviridae. CONCLUSIONS: Altogether, the properties of E. coli H22, observed both under in vitro and in vivo conditions, suggest its potential use as a probiotic strain for livestock and humans. SIGNIFICANCE AND IMPACT OF THE STUDY: The strain H22 was shown to produce several antimicrobial compounds with inhibitory capabilities against pathogenic or potentially pathogenic enterobacteria.

Multiple antimicrobial resistance in Enterobacteriaceae isolates from pristine freshwater

A freshwater enterobacterial population (N = 111) was studied for antimicrobial and mercury resistance patterns, and for its possible association with biotic and abiotic factors in that environment. Conventional biochemical tests identified Klebsiella sp, Morganella sp, Serratia sp, Escherichia sp, Enterobacter sp, Edwarsiella sp, Proteus sp, Citrobacter sp, Providencia sp, and Kluyvera sp. There was no correlation between antimicrobial resistance patterns of isolates and bacterial genera, but resistance patterns varied among water samples and between seasons. Resistance to multiple antimicrobials was common (61%). The percentage of bacteria resistant to at least one antimicrobial differed between the rainy (100%) and dry seasons (89%). Resistance to â-lactams and chloramphenicol was the most frequent and resistance to amikacin, gentamicin and kanamycin was less frequent. The main water variables examined (abiotic factors pH and temperature; biotic factor chlorophyll a concentration) did not influence antimicrobial resistance. Significant impact on freshwater enterobacteria, as evidenced by antimicrobial-multiple resistance and by the presence of blaTEM gene, may point to the fact that it has an important role in horizontal spread of resistance.