Resumo A presença de bactérias patogênicas em alimentos é considerada a principal causa de doenças transmitidas por alimentos e deterioração da qualidade dos alimentos em todo o mundo. O presente estudo teve como objetivo determinar a eficácia de cinco óleos essenciais (OEs) contra patógenos de origem alimentar multirresistentes. No presente estudo, bactérias Gram-negativas (Escherichia, Enterobacter, Citrobacter, Proteus, Pseudomonas e Klebsiella) e as bactérias Gram-positivas Staphylococcus foram isoladas do leite cru e caracterizadas bioquimicamente. O efeito antibacteriano de diferentes antibióticos e OEs (tomilho, orégano, capim-limão, hortelã e alecrim) foi determinado usando o método padrão de difusão em disco. O estudo do antibiograma revelou que as bactérias Gram-negativas eram altamente resistentes à penicilina, enquanto o Staphylococcus era resistente à estreptomicina, amoxicilina e lincomicina. Foi observada resistência moderada à doxiciclina, amicacina, enrofloxacina, canamicina e cefixima. Os isolados foram encontrados menos resistentes à gentamicina, cloranfenicol e ciprofloxacina. Os OEs mostraram uma ampla gama de atividade antimicrobiana contra todas as bactérias, exceto P. aeruginosa. Destes, o tomilho foi mais eficaz contra a maioria das cepas bacterianas multirresistentes e formou a maior zona de inibição (26 mm) contra Escherichia seguido de óleo de orégano (18 mm) contra Staphylococcus (p<0,05). Klebsiella spp e Citrobacter spp apresentaram resistência ao óleo de menta e capim-limão, respectivamente. Os OEs como capim-limão, hortelã e alecrim foram menos ativos contra todas as bactérias. Os resultados do estudo recente sugerem o uso de OEs como agentes antibacterianos naturais para conservação de alimentos.

Abstract The presence of pathogenic bacteria in food is considered as a primary cause of food-borne illness and food quality deterioration worldwide. The present study aimed to determine the effectiveness of five essential oils (EOs) against multidrug-resistant foodborne pathogens. In the current study Gram-negative bacteria (Escherichia, Enterobacter, Citrobacter, Proteus, Pseudomonas, and Klebsiella) and the Gram-positive bacteria Staphylococcus were isolated from raw milk and biochemically characterized. The anti-bacterial effect of different antibiotics and EOs (thyme, oregano, lemongrass, mint, and rosemary) was determined using the standard disc diffusion method. The antibiogram study revealed that Gram-negative bacteria were highly resistant to penicillin while Staphylococcus was resistant to streptomycin, amoxicillin, and lincomycin. Moderate resistance was observed to doxycycline, amikacin, enrofloxacin, kanamycin and cefixime. Isolates were found less resistant to gentamycin, chloramphenicol, and ciprofloxacin. EOs showed a broad range of antimicrobial activity against all bacteria except P. aeruginosa. Of these, thyme was more effective against most of the multi-drug resistant bacterial strains and formed the largest zone of inhibition (26 mm) against Escherichia followed by oregano oil (18 mm) against Staphylococcus (p<0.05). Klebsiella spp and Citrobacter spp showed resistance to mint and lemongrass oil respectively. The EOs such as lemongrass, mint and rosemary were less active against all the bacteria. The findings of the recent study suggest the use of EOs as natural antibacterial agents for food preservation.

RESUMO: Um experimento foi conduzido para avaliar os efeitos resultantes do sistema de pré-germinação, priming, padrões de plantio e tratamentos de controle de ervas daninhas sobre o espectro da erva daninha, rendimento de grãos e rentabilidade do trigo, durante o período de desenvolvimento da planta de 2013-14. As sementes foram preparadas de duas formas: sem a utilização do sistema de priming, e sob condicionamento osmótico, osmopriming. Os padrões de plantio foram semeadura a lance (broadcast) e em linha (row plantation) e quarto dosagens de herbicidas foram aplicadas (pyroxulam nas dosagens 14,08, 10,56, 7,04 e 7,521 g i.a. ha-1), em um delineamento inteiramente casualizado em sistema de parcela subdividida split-plot. Os dados relativos à densidade de plantas daninhas, ao estabelecimento, ao crescimento e ao rendimento dos traços de trigo associados foram registrados e analisados por técnica de análise de variância usando software estatístico DSAASTAT. Os resultados revelaram que a contagem final de emergência foi significativamente melhorada pela semeadura em linha. Os tratamentos de preparação de sementes resultaram em emergência prévia de colheita e propagação do dossel e também diminuiu a densidade de ervas daninhas e o peso seco em 13% e 18%, respectivamente, a 60 DAS (dias após a semeadura). Além disso, o rendimento de grãos foi melhorado em 8% também nas parcelas de tratamento de cebola. A semeadura em linha do tratamento do trigo diminuiu a densidade de ervas daninhas e o peso seco em 17% e 25%, respectivamente, com um rendimento de grão melhorado em 14% em relação ao método de semeadura a lance. O Pyroxulam com uma taxa de 14,08 g i.a. ha-1 aplicado a 60 DAS reduziu a densidade total de ervas daninhas e o peso seco em 88% e 96%, respectivamente, e o rendimento de grãos foi melhorado em 36% em relação às parcelas de verificação de plantas daninhas. Em conclusão, as sementes sob condicionamento osmótico (1% de KCl) semeadas em linhas de 22,5 cm de distância proporcionaram maior produção de trigo, as ervas daninhas foram devidamente controladas por aplicação de piroxulam aplicado na dose recomendada (14,08 g i.a. ha-1) e também 75% da dose recomendada sob condições de Faisalabad.

ABSTRACT: An experiment was conducted to evaluate the effect of priming, planting patterns and weed control treatments on weed spectrum, grain yield and profitability of wheat, during the growing season 2013-14. Two levels of seed priming (no priming, osmopriming) and planting patterns (broadcast, row plantation), and four levels of herbicide (pyroxulam at the rate of 14.08, 10.56, 7.04 and 7.521 g a.i. ha-1) were employed in the experiment, laid out in a randomized complete block design with split-split plot arrangement. The data regarding weed density, stand establishment, growth, and yield associated traits of wheat were recorded and analyzed by analysis of variance technique using statistical software DSAASTAT. The results revealed that the final emergence count was improved significantly by line sowing. The seed priming treatments resulted in early crop emergence and canopy spread, and it also decreased weed density and dry weight by 13% and 18%, respectively at 60 DAS (days after sowing). Moreover, grain yield was improved by 8% in priming treatment plots. Whereas, line sowing of wheat treatment decreased the weed density and dry weight by 17% and 25% respectively, with improved grain yield by 14% over the broadcast method. Pyroxulam at the rate of 14.08 g a.i. ha-1 applied at 60 DAS reduced total weed density and dry weight by 88% and 96% respectively and grain yield was improved by 36% over weedy check plots. In conclusion, osmoprimed seeds (1% KCl) sown in lines 22.5 cm apart gave higher wheat yields where weeds were properly controlled through application of pyroxulam applied at its recommended dose (14.08 g a.i. ha-1) and also 75% of recommended dose under Faisalabad conditions.

Boron (B) deficiency in rice field is becoming a common problem in South Asia. Correcting B deficiency in rice has potential to improve the rice productivity. Foliage application of B is an easy and effective way to resolve this problem. This study was conducted to evaluate the influence of foliage applied (0.16, 0.24, 0.32, 0.40 and 0.48 M) B on leaf elongation, tillering, water relations, yield and B grain enrichment of rice cultivars Super Basmati and Shaheen Basmati. Foliage applied B improved leaf elongation, tillering, leaf chlorophyll contents, water relations, grain yield, yield-related traits and B grain contents with simultaneous decrease in panicle sterility. However, foliage application of 0.32 M B was the most effective in this regard. An increase in leaf and grain B contents was observed with increase in B concentration in the foliar spray. There was no difference between the cultivars for grain yield; however, Shaheen Basmati had more grain weight, and grain and leaf B contents than Super Basmati. Boron foliage application (0.32 M B) proved an effective way to correct B deficiency in rice. Improvement in grain yield by B application was attributed to increase in grain size and decrease in panicle sterility.