Because many natural resources are limited, sustainability becomes an important concept in maintaining the human population, health, and environment. Mushrooms are a group of saprotrophic fungi. Mushroom cultivation is a direct utilization of their ecological role in the bioconversion of solid wastes generated from industry and agriculture into edible biomass, which could also be regarded as a functional food or as a source of drugs and pharmaceuticals. To make the mushroom cultivation an environmentally friendly industry, the basic biology of mushrooms and the cultivation technology must be researched and developed. This is very true for Lentinula edodes, Volvariella volvacea, and Ganoderma lucidum, which are commonly consumed in Asian communities but are now gaining popularity worldwide. Besides the conventional method, strain improvement can also be exploited by protoplast fusion and transformation. Biodiversity is the key contribution to the genetic resource for breeding programs to fulfill different consumer demands. The conservation of these mushrooms becomes essential and is in immediate need not only because of the massive habitat loss as a result of human inhabitation and deforestation, but also because of the introduced competition by a cultivar with the wild germ plasm. Spent mushroom compost, a bulky solid waste generated from the mushroom industry, however, can be exploited as a soil fertilizer and as a prospective bioremediating agent.
The microbial degradation of polychlorinated biphenyls (PCBs) has been extensively conducted by many workers, and the following general results have been obtained. (1) PCBs are degraded oxidatively by aerobic bacteria and other microorganisms such as white rot fungi. PCBs are also reductively dehalogenated by anaerobic microbial consortia. (2) The biodegradability of PCBs is highly dependent on chlorine substitution, i.e., number and position of chlorine. The degradation and dehalogenation capabilities are also highly strain dependent. (3) Biphenyl-utilizing bacteria can cometabolize many PCB congeners to chlorobenzoates by biphenl-catabolic enzymes. (4) Enzymes involved in the PCB degradation were purified and characterized. Biphenyl dioxygenase, ring-cleavage dioxygenase, and hydrolase are crystallized, and two ring-cleavage dioxygenases are being solved by x-ray crystallography. (5) The bph gene clusters responsible for PCB degradation are cloned from a variety of bacterial strains. The structure and function are analyzed with respect to the evolutionary relationship. (6) The molecular engineering of biphenyl dioxygenases is successfully performed by DNA shuffling, domain exchange, and subunit exchange. The evolved enzymes exhibit wide and enhanced degradation capacities for PCBs and other aromatic compounds.
Five ballistoconidiogenous yeast strains, isolated from plant leaves at Cuc Phuong National Forest of Ninh Binh, Vietnam, were assigned to the genus Kockovaella based on morphological and chemotaxonomical characteristics. They represent four new species based on analyses of 18S rDNA sequence, sequences of internal transcribed spacer regions, and DNA-DNA reassociation experiments. Four new species, Kockovaella calophylli (1 strain), Kockovaella cucphuongensis (2 strains), Kockovaella litseae (1 strain), and Kockovaella vietnamensis (1 strain) are proposed for these strains.
Abf2p, a mitochondrial DNA-binding protein of yeast Saccharomyces cerevisiae, was selectively detected among mitochondrial nucleoid proteins by SDS-DNA polyacrylamide gel electrophoresis (SDS-DNA PAGE) followed by ethidium bromide staining. This method is simple and specific for the detection of Abf2p, and it may be used to identify an Abf2p-like protein that is present in mitochondrial nucleoids from other yeasts.