ABSTRACT
Cyanobacterial pigments such as chlorophyll, carotenoids and phycobiliproteins are considered as ecofriendly natural colourants used in food and food additives as they have nutraceutical value, non-toxic and non-carcinogenic. The present study focused on extraction, partial characterization of extracellular polysaccharides (EPS), phycocyanin and mycosporin like amino acid (MAA) from a freshwater cyanobacterium Oscillatoria pseudogeminata G.Schmid.The purified isolate of O.pseudogeminatawas deposited and maintained in the NRMC-F, Bharathidasan University. The EPS was extracted withthe help of double volume of ice-cold acetone and confirmed by UV (260 and 280 nm), FTIR and XRD analyses.Phycocyanin and MAA were also extracted from O. pseudogeminata biomass using double distilled water. The UV-VisSpectrophotometric results revealed that 520 and 230 nm peaks represent phycocyanin and MAA, respectively. Further, theprocess of scaling-up the biomass and increase the productivity of EPS, Phycocyanin and MAA from Oscillatoriapseudogeminata is under raceway pond system, already initialed in our laboratory.
ABSTRACT
Objective: To evaluate the antibacterial efficacy of five Indian medicinal plants such as Acalypha indica L. (A. indica), Aerva lanata (L.) Juss. ex Schult. (A. lanata), Clerodendrum inerme (L.) Gaertn., Pergularia daemia (Forsk.) Chiov. and Solanum surattense Burm. f. against opportunistic bacterial pathogens isolated from HIV infected patients for the potential phytoconstituents in plant extracts. Methods: The opportunistic bacterial pathogens such as Escherichia coli (E. coli), Pseudomonas aeruginosa, Salmonella typhi and Serratia marcescens from Gram-negative group and Staphylococcus aureus from Gram-positive group were isolated from HIV infected patients. The antibacterial efficacy of ethanolic extracts of selected medicinal plants was carried out by disc diffusion method. The potential phytoconstituents of medicinal plant extracts were identified by gas chromatography and mass spectrometry (GC-MS) analysis. Results: Among the five medicinal plants tested, A. indica and A. lanata showed the significant antibacterial activity. A. indica showed potential activity against Staphylococcus aureus and E. coli. A. lanata significantly exhibited antibacterial activity against E. coli, Salmonella typhi and Pseudomonas aeruginosa. A total of 19 phytoconstituents were identified in the ethanolic extract of A. indica and A. lanata by GC-MS analysis respectively. Conclusions: The results of the present investigation revealed that A. indica and A. lanata, possessed significant antibacterial activity when compared with the other plant extracts tested. The presence of 3-O-methyl- d-glucose by GC-MS analysis in both A. indica and A. lanata extracts has not been reported elsewhere in the literature and the findings in this study could be the first one to report.
ABSTRACT
A variety of foods and environmental sources harbor bacteria that are resistant to one or more antimicrobial drugs used in medicine and agriculture. Antibiotic resistance in Escherichia coli is of particular concern because it is the most common Gram-negative pathogen in humans. Hence this study was conducted to determine the antibiotic sensitivity pattern of E. coli isolated from different types of food items collected randomly from twelve localities of Hyderabad, India. A total of 150 samples comprising; vegetable salad, raw egg-surface, raw chicken, unpasteurized milk, and raw meat were processed microbiologically to isolate E. coli and to study their antibiotic susceptibility pattern by the Kirby-Bauer method. The highest percentages of drug resistance in isolates of E. coli were detected from raw chicken (23.3%) followed by vegetable salad (20%), raw meat (13.3%), raw egg-surface (10%) and unpasteurized milk (6.7%). The overall incidence of drug resistant E. coli was 14.7%. A total of six (4%) Extended Spectrum β-Lactamase (ESBL) producers were detected, two each from vegetable salads and raw chicken, and one each from raw egg-surface and raw meat. Multidrug resistant strains of E. coli are a matter of concern as resistance genes are easily transferable to other strains. Pathogen cycling through food is very common and might pose a potential health risk to the consumer. Therefore, in order to avoid this, good hygienic practices are necessary in the abattoirs to prevent contamination of cattle and poultry products with intestinal content as well as forbidding the use of untreated sewage in irrigating vegetables.
Variedade de alimentos e fontes ambientais contem bactérias resistentes a uma ou mais drogas antimicrobianas usadas em medicina e agricultura. Resistência antibiótica pela Escherichia coli é particularmente preocupante porque ela é o patógeno mais comum Gram negativo em humanos. Portanto este estudo foi conduzido para determinar o aspecto de sensibilidade antibiótica da E. coli isolados de diferentes tipos de alimentos obtidos ao acaso de 12 localidades de Hyderabad, India. Um total de 150 amostras compreendendo saladas, vegetais, superfícies de ovos crus, galinhas cruas, leite não pasteurizado e carne crua foram processados microbiologicamente para isolar E. coli e estudar o quadro de sensibilidade antibiótica pelo método de Kirby-Bauer. A maior percentagem de resistência à droga foi isolada de E. coli obtidos de galinha crua (23,3%) seguido de saladas e vegetais (20%), carne crua (13,3%), superfície do ovo cru (10%) e leite não pasteurizado (6,7%). Incidência total de E. coli resistente foi de 14,7%. Um total de seis (4%) Extended Spectrum β-Lactamase (ESBL) produtores foram detectados, dois cada de salada de vegetais e galinha crua e um cada de superfície de ovo cru e carne crua. Espécies resistentes a múltiplas drogas de E. coli são matéria de preocupação uma vez que os genes de resistência podem facilmente ser transferidos para outras linhagens. O ciclo do patógeno é muito comum nos alimentos e pode ser risco potencial para a saúde do consumidor. Portanto, para evitar isto boas práticas de higiene são necessárias nos abatedouros para prevenir a contaminação de gado e aves com conteúdo intestinal assim como proibir o uso de águas de esgoto não tratadas para irrigar vegetais.