Growth-promoting rhizobacteria are soil bacteria that inhabit the surrounding root, and are directly or indirectly involved in promoting plant growth and development. The productivity efficiency of these groups of microorganisms can be applied to planting crops, providing an interesting alternative for minimize the negative effects of water deficit. The objective of this study was to verify if the mechanism of growth promotion of the bacterium is similar to that promoted by polyethylene glycol (PEG) and to compare the possible effects of water stress on the tomato against the effects of inoculation of the bacterium Serratia sp. The methodology was based on in vitro bioassays using tomato (Solanum lycopersicum L.) seedlings, kept in a growth chamber with temperature of 25 °C and photoperiod of 12 hours. The results revealed that the promotion of tomato root growth by Serratia sp. is similar to that promoted by PEG 7%, differing significantly from the results found with different doses of indoleacetic acid (IAA). The promotion of root growth in tomatoes by Serratia sp. and PEG 7% partly indicates a physical effect, since the water restriction imposed by the PEG molecule decreases the water movement capacity, also observed by bacteria, when colonizing plant tissues and cells (biofilm) reducing the hydraulic conductivity of water through the root. Stimulation to promote root growth in tomatoes cannot be reproduced by auxin.

No Brasil, de um modo geral, o leite é obtido em condições higiênico-sanitárias deficientes, em consequência, apresenta elevado número de microrganismos contaminantes. O crescimento microbiano no leite causa um grande prejuízo econômico para as indústrias de beneficiamento. Os fungos desempenham um importante papel na indústria de produtos lácteos, pois podem promover deterioração ou desencadear fermentação e/ou maturação indesejáveis aos derivados do leite. O presente trabalho objetivou investigar a relação entre contagem bacteriana total (CBT) e o isolamento de fungos filamentosos e leveduras em amostras de leite do tanque de expansão. O leite de 160 propriedades foi monitorado por 6 meses quanto à contagem de células somáticas (CCS) e CBT por métodos oficiais. Foram analisadas amostras de 120 propriedades quanto à CBT e isolamento de fungos. Em 102 amostras (85%) foram isolados fungos filamentosos (Acremonium sp., Alternaria spp., Aspergillus sp., Cladosporium sp., Fusarium sp., Mucor spp., Penicillium sp.) e/ou leveduras Candida sp., Geotrichum sp., Pichia sp., Prothoteca sp., Rodothorula sp., Trichosporon sp.) com média de 1.284 UFC/mL e CBT de 133.000 UFC/mL. Em 14 amostras negativas para fungos obteve-se uma média de 652.000 UFC/mL para a CBT. A diferença da CBT entre amostras positivas e negativas para fungos foi significativa (p<0,001), demonstrando a influência dos fungos sobre o crescimento bacteriano e a CBT do leite. A presença de fungos e o potencial risco de produção de toxinas no leite cru e seus derivados devem ser investigadas, bem como a relação entre o isolamento de fungos e a baixa CBT do leite.

Two experiments evaluated the effects of copper (Cu) and zinc (Zn) injection on body weight (BW), body condition score (BCS), pregnancy rate, ovarian traits, and antioxidant and inflammatory responses of beef heifers. In Exp. 1, 29 heifers were assigned to having saline or CuZn (a solution containing 15 and 50 mg/mL of Cu and Zn) subcutaneously injected (5 mL/heifer) 9 days before artificial insemination. Exp. 2 was conducted to increase the statistical power to evaluate pregnancy rate, and 283 heifers were assigned to either the saline or CuZn group. In Exp. 1, CuZn heifers tended (p ≤ 0.10) to gain more BW and to have greater corpus luteum size and plasma concentration of glutathione peroxidase. No effects of treatment were detected (p ≥ 0.18) for BCS; estrus score; serum concentration of Cu, Zn, and cortisol; and plasma concentration of haptoglobin, ceruloplasmin, and superoxide dismutase. In Exp. 2, CuZn heifers had greater (p < 0.01) BW and serum Cu. The CuZn heifers with low BCS had greater (p ≤ 0.05) estrus scores and tended (p = 0.10) to have greater pregnancy rates. Thus, injecting CuZn may be an effective strategy to enhance growth, reproductive performance, and antioxidant responses in heifers, especially when their BCS is below 5.

The importance of beef (ground) in human food and the concern to offer an innocuous food that is incapable of transmitting diseases led to the development of this study, which aimed to evaluate the microbiological quality, the antimicrobial sensitivity profile and the hygienic-sanitary conditions in samples of beef (ground), sold in the Municipalities of Valença and Vassouras, RJ. Samples were carried out in 20 commercial establishments, which offer ground meat under conditions of consumption and analyzed according to the coliform quantification technique in MPN/g. The antimicrobial profile of Escherichia coli isolates was submitted to susceptibility tests to tetracycline (30μg), ampicillin (10μg), cephalothin (30μg), gentamicin (10μg) and cefotaxime (30μg), using the disk-diffusion method. The assessment of hygienic-sanitary conditions, on the other hand, was based on pre-established observation criteria in a model questionnaire. The total coliform indices were greater than 240 MPN/g in 90% of the analyzed samples and 55% of the samples had indices greater than 240 MPN/g for thermotolerant coliforms, and the Municipality of Valença revealed 40% of contamination within the sample universe. The evaluation of the antimicrobial profile for the antibiotic cefotaxime showed a greater spectrum of action for strains of Escherichia coli isolated from the samples, while the highest index of resistance was observed for the antibiotic cephalothin. The evaluation of hygienic-sanitary conditions was considered unsatisfactory in relation to the handling of meat, which makes this type of food a potential cause of food poisoning.