Morphological and physiological variation among different isolates of Alternaria spp. from Rapeseed-Mustard

To find out the Morphological variation on growth and sporulation of Alternaria species of Alternaria leaf blight of mustard from 10 representative geographical locations of Bangladesh, this experiment was conducted at Plant Pathology Laboratory, Oilseed Research center, Bangladesh Agricultural Research Inistitute (BARI), Joydevpur, Gazipur, Bangladesh. All the isolates showed high level of variability in in-vitro in respect of radial mycial growth, colony colour, sub surface colour, colony shape, colony texture, zonation (surface and sub surface), length and width of conidia, beak length and number of septa. The maximum and minimum radial mycial growth was recorded 90 mm in isolate NATAb and 83.67 mm in isolate GAZAb, respectively at 14 days after incubation. Significant variation in conidial length, width, beak and no. of conidia observed in all isolates. The length of conidia ranged from 41.56 to 117.54µm with 3 to 11 transverse and 0 to 3 vertical septa. The width and beak length varied from 10.34 to 23.12 µm and 16.78 to 72.65 µm ,respectively. Surface colour were olivacious green to black and circular shaped colonies were observed in all isolates on PDA medium. Colony texture were cottony to velvety. Subsurface colour varied from light brown to black and pinkish. Zonation found in some isolates and some did not produce on both surface and subsurface. All conidia were murifrom and light brown to deep brown in colour. Potato Carrot Dextrose Agar medium (PCDA) and 25 o C temperature were found optimum for different isolates for mycelial growth and sporulation

Human Gut Microbiota: Toward an Ecology of Disease

Composed of trillions of individual microbes, the human gut microbiota has adapted to the uniquely diverse environments found in the human intestine. Quickly responding to the variances in the ingested food, the microbiota interacts with the host via reciprocal biochemical signaling to coordinate the exchange of nutrients and proper immune function. Host and microbiota function as a unit which guards its balance against invasion by potential pathogens and which undergoes natural selection. Disturbance of the microbiota composition, or dysbiosis, is often associated with human disease, indicating that, while there seems to be no unique optimal composition of the gut microbiota, a balanced community is crucial for human health. Emerging knowledge of the ecology of the microbiota-host synergy will have an impact on how we implement antibiotic treatment in therapeutics and prophylaxis and how we will consider alternative strategies of global remodeling of the microbiota such as fecal transplants. Here we examine the microbiota-human host relationship from the perspective of the microbial community dynamics