Progress and prospect of single-molecular ClpX ATPase researching system-a mini-review.

ClpXP in Escherichia coli is a proteasome degrading protein substrates. It consists of one hexamer of ATPase (ClpX) and two heptamers of peptidase (ClpP). The ClpX binds ATP and translocates the substrate protein into the ClpP chamber by binding and hydrolysis of ATP. At single molecular level, ClpX harnesses cycles of power stroke (dwell and burst) to unfold the substrates, then releases the ADP and Pi. Based on the construction and function of ClpXP, especially the recent progress on how ClpX unfold protein substrates, in this mini-review, a currently proposed single ClpX molecular model system detected by optical tweezers, and its prospective for the elucidation of the mechanism of force generation of ClpX in its power stroke and the subunit interaction with each other, were discussed in detail.

Isolation and Identification of Endophytic Fungi in Kernels of Coix lachrymal-jobi L. Cultivars.

Coix lachrymal-jobi L. var. ma-yuen Stapf of Gramineae are annual or perennial herbs and an important food-medicine homologous plants of high value in nutrition, health protection, and comprehensive utilization. In recent years, the revival of researches on its roles in food and medicinal applications of this underutilized grass for food security and economic empowerment of rural communities has been seen . In this research, Coix kernel endophytic fungi were isolated and identified by fungal colony morphology observation combined with the PCR-amplified fungal internal transcribed spacer (ITS) sequence analyses. All together six isolates to five species of Coix endophytic fungi and two isolates to the genus level were identified from the kernels of six Coix cultivars: Penicillium expansum, Penicillium polonicum, Cladosporium cladosporioides, Alternaria alternata, Aspergillus flavus, and two genera of Aspergillus and Fusarium. Potential benefits and harms analyses showed that Penicillium expansum, Aspergillus oryzae, and Cladosporium cladosporioides can produce a variety of beneficial composite enzymes and have an extensive application in microbial chemistry, food science, and fermentation, whereas Penicillium, Aspergillus flavus, Alternaria alternate, and Fusarium can produce corresponding toxins harmful to plants, animals, and humans. These results not only provided a basis for the targeted prevention of contamination in the tissue culture of Coix kernels by the addition of specific antibiotics, but also enriched the endophytic fungi resource pool of Gramineae crops and suggested new ideas for the improvement, cultivation, post-harvest seeds/kernels storage, and the development of new natural drugs.

EST-based profiling and comparison of gene expression in the silkworm fat body during metamorphosis.

The fat body plays key roles in metabolism and sustenance of growth throughout the life of a silkworm, and thus represents a model tissue for studying development and metamorphosis. Analysis of 18,480 ESTs derived from larval and pupal fat body cDNA libraries allowed characterization of gene expression patterns in the fat body during metamorphosis. By Phrap assembling, 6,814 estimated transcription units (TUs) were generated, 2,673 of which contained 60% of the total ESTs and represented 1,366 distinctive known genes. These genes were classified into 14 categories based on their known or putative functions, and most were found to be involved in metabolism and cell defense. Further comparative analysis of the expression profiles revealed that the gene expression patterns in the larval fat body strikingly differed from those in the pupal fat body. From this, we identified a subset of genes potentially associated with metamorphic events such as the formation or destruction of specific tissues, and simultaneously confirmed the stage-specific expression patterns of several identified genes using RT-PCR examination. This work will provide a valuable resource for studying regulatory mechanisms associated with fat body developmental changes and silkworm metamorphosis.