Abstract Zinc is one of the most important trace elements and deficiency can lead to significant clinical complications. Microbial transformation is one of the most important methods used to supplement organic zinc and there may be some naturally occurring microorganisms that have both higher zinc tolerances and transformation capabilities. In this study, microorganisms which displayed such characteristics were widely screened, and a strain designated T-A was found. Morphological and molecular determination demonstrated that T-A is closely related to Candida tropicalis with 87% of 18S rDNA homology, with a G+C content measured by RP-HPLC of 88.42%. Candida tropicalis sp. T-A strains were shown to grow and transform zinc best at pH5 in medium with a zinc ion concentration of 8000 μg/mL at 28 °C for 121 hours. Our results showed C. tropicalis sp. T-A’s zinc content was 19.153 mg/g dry weight, with a relative bioavailability in rats of 173% when compared with traditional zinc supplements. Our study suggests that C. tropicalis sp. T-A could be exploited for use as a potential zinc supplement.

This study investigated the chemical composition, and antimicrobial and anti-wood-decay fungal activities of the essential oil isolated from the leaf of endemic Machilus zuihoensis Hayata, Lauraceae, of Taiwan. The essential oil from the fresh leaves of M. zuihoensis was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. A total of 104 compounds were identified, representing 100% of the oil. The main components identified were n-dodecanal (23.8%) and (E)-nerolidol (10.5%). The antimicrobial activity of the oil was tested by the disc diffusion method and micro-broth dilution method against ten microbial species (Bacillus cereus, Staphylococcus aureus, S. epidermidis, Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Vibrio parahaemolyticus, Aspergillus niger, and Candida albicans), respectively. The oil exhibited strong growth suppression against Gram-positive bacteria and yeast with inhibition zones of 35~43 mm to MIC values of 125 µg mL-1, respectively. The anti-wood-decay fungal activity of the oil was also evaluated. Results showed that the oil demonstrated excellent activity against four wood-decay-fungi species (Trametes versicolor, Phaneochaete chrysosporium, Phaeolus schweintizii, and Lenzites sulphureu). For the antimicrobial and anti-wooddecay fungal activities of the oil, the active source compounds were determined to be τ-cadinol, β-eudesmol, and n-dodecanal.

Major histocompatibility complex class I chain-related A (MICA) is a highly polymorphic gene located within the MHC class I region of the human genome. Expressed as a cell surface glycoprotein, MICA modulates immune surveillance by binding to its cognate receptor on natural killer cells, NKG2D, and its genetic polymorphisms have been recently associated with susceptibility to some infectious diseases. We determined whether MICA polymorphisms were associated with the high rate of Schistosoma parasitic worm infection or severity of disease outcome in the Dongting Lake region of Hunan Province, China. Polymerase chain reaction-sequence specific priming (PCR-SSP) and sequencing-based typing (SBT) were applied for high-resolution allele typing of schistosomiasis cases (N = 103, age range = 36.2-80.5 years, 64 males and 39 females) and healthy controls (N = 141, age range = 28.6-73.3 years, 73 males and 68 females). Fourteen MICA alleles and five short-tandem repeat (STR) alleles were identified among the two populations. Three (MICA*012:01/02, MICA*017 and MICA*027) showed a higher frequency in healthy controls than in schistosomiasis patients, but the difference was not significantly correlated with susceptibility to S. japonicum infection (Pc > 0.05). In contrast, higher MICA*A5 allele frequency was significantly correlated with advanced liver fibrosis (Pc < 0.05). Furthermore, the distribution profile of MICA alleles in this Hunan Han population was significantly different from those published for Korean, Thai, American-Caucasian, and Afro-American populations (P < 0.01), but similar to other Han populations within China (P > 0.05). This study provides the initial evidence that MICA genetic polymorphisms may underlie the severity of liver fibrosis occurring in schistosomiasis patients from the Dongting Lake region.