Anabolic utilization of steroid hormones in Helicobacter pylori

In this study, we have demonstrated that Helicobacter pylori absorbs a steroid prehormone (pregnenolone) and two androgens (dehydroepiandrosterone and epiandrosterone), glucosylates these steroids, and utilizes glucosyl-steroid hormone compounds as the membrane lipid components. The only common structure among the steroid prehormone and the two androgens is a 3β-OH in the steroid framework. Our results indicate that the 3β-OH in the steroid hormones is a crucial conformation required for steroid glucosylation by H. pylori . In addition, we found that H. pylori absorbs and holds estrogens possessing 3-OH (estrone and estradiol) into the membrane. The effective absorption of estrogen into the membrane appeared to be controlled by the number of hydroxyl groups modifying the steroid framework. In contrast, H. pylori induced neither membrane absorption nor glucosylation of the other steroid hormones possessing 3=O (progesterone, androstenedione and testosterone) or 3α-OH (androsterone). These results indicate that H. pylori selectively absorbs 3β-OH and 3-OH steroid hormones, and utilizes only 3β-OH steroid hormones as the materials for glucosylation.     

Additional genes essential for replication of the mini-F plasmid from origin I

Summary We isolated a series of Tn5-insertional mutants from the mini-F plasmid, which has a deletion in the origin II region and replicates exclusively from origin I, and found that the mutants that had Tn5 in either the F4 or the F5 gene were defective in their replication. It is concluded that, in addition to the F3 gene on which we have reported previously, both the F4 and the F5 genes are essential for the replication from origin I.     

Increased frequency of specific alleles of the c-Ha-ras gene in Japanese cancer patients

Summary We have examined the c-Ha-ras locus in 145 cancer patients of a mixed group and 164 normal individuals in Japan for restriction fragment length polymorphisms and compared the allele distributions in normal and cancer populations. The c-Ha-ras gene is highly polymorphic in Japanese as previously reported in Caucasians. Two rare alleles were found to be present with increased frequencies in Japanese cancer patients. These results suggest that genotype analysis of the c-Ha-ras gene could be used to detect cancer-prone individuals.     

Development of surface‐engineered yeast cells displaying phytochelatin synthase and their application to cadmium biosensors by the combined use of pyrene‐excimer fluorescence

The development of simple, portable, inexpensive, and rapid analytical methods for detecting and monitoring toxic heavy metals are important for the safety and security of humans and their environment. Herein, we describe the application of phytochelatin (PC) synthase, which plays a critical role in heavy metal responses in higher plants and green algae, in a novel fluorescent sensing platform for cadmium (Cd). We first created surface‐engineered yeast cells on which the PC synthase from Arabidopsis (AtPCS1) was displayed with retention of enzymatic activity. The general concept for the sensor is based on the Cd level‐dependent synthesis of PC₂ from glutathiones by AtPCS1‐displaying yeast cells, followed by simple discriminative detection of PC₂ via sensing of excimer fluorescence of thiol‐labeling pyrene probes. The intensity of excimer fluorescence increased in the presence of Cd up to 1.0 μM in an approximately dose‐dependent manner. This novel biosensor achieved a detection limit of as low as 0.2 μM (22.5 μg/L) for Cd. Although its use may be limited by the fact that Cu and Pb can induce cross‐reaction, the proposed simple biosensor holds promise as a method useful for cost‐effective screening of Cd contamination in environmental and food samples. The AtPCS1‐displaying yeast cells also might be attractive tools for dissection of the catalytic mechanisms of PCS. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:1197–1202, 2013     

GC-->CG transversion mutation might be caused by 8-oxoguanine oxidation product.

Oxidation of d(A6GGA6)/d(T6CCT6) with sensitizer under different UV irradiation periods was examined. Enzymatic digestion of photolysate revealed that the amount of 8-oxoG initially increased with decrease of G and then decreased with the formation of Iz. In order to investigate whether Iz was formed by one electron oxidation of 8-oxoG through long-range hole migration, photoirradiation of anthraquinone-linked oligomer was examined. The results clearly demonstrated that 8-oxoG was efficiently converted to Iz under irradiation conditions. These results suggest that Iz generated from 8-oxoG induces GC->CG transversion under oxidative condition.     

A case of chronic necrotizing pulmonary aspergillosis due toAspergillus nidulans

A 55-year old man without immunosuppression clinically showed a coin lesion in the right lower lung on the chest radiographs.Aspergillus nidulans was isolated and identified in both trans-bronchial lung biopsy specimen and resected tissue. The specimens revealed characteristics of chronic necrotizing pulmonary aspergillosis pathologically. Very few reports on cases of pulmonary aspergillosis due toA. nidulans exist, and we were not able to find any reports of similar cases. This case may be the first reported case of chronic necrotizing pulmonary aspergillosis due toA. nidulans.