AIM:To determine if disruption of the cagA gene of Helicobacter pylori (H pylori ) has an effect on the expression of other proteins at proteome level.METHODS: C o n s t r u c t i o n o f a cagA k n o c k o u t m u t a n t H p 2 7 _ ∆c a g A (c a g A -) v i a h o m o l o g o u s re c o m b i n a t i o n w i t h t h e w i l d -ty p e s t ra i n Hp27 (cagA + ) as a recipient was performed. The method o f s o n i c a t i o n -u r e a -C H A P S -DTT wa s e m p l o ye d to extract bacterial proteins from both strains. Soluble proteins were analyzed by two-dimensional electrophoresis (2-DE). Images of 2-DE gels were digitalized and analyzed. Only spots that had a statistical significance in differential expression were selected and analyzed by matrix-assisted laser desorption/ionizationtime of flight mass spectrometry (MALDI-TOF-MS). Biological information was used to search protein database and identify the biological function of proteins. RESULTS:The proteome expressions between wild-type strain and isogenic mutant with the cagA gene knocked-out were compared. Five protein spots with high abundance in bacteria proteins of wild-type strains, down-regulated or absently expressed in bacteria proteins of mutants, were identified and analyzed. From a quantitative point of view, the identified proteins are related to the cagA gene and important antioxidant proteins of H pylori , including alkyl hydroperoxide reductase (Ahp), superoxide dismutase (SOD) and modulator of drug activity (Mda66), respectively, suggesting that cagA is important to maintain the normal activity of antioxidative stress and ensure H pylori persistent colonization in the host. C O N C L U S I O N :c a g A g e n e i s r e l e v a n t t o t h e expressions of antioxidant proteins of H pylori , which may be a novel mechanism involved in H pylori cagA pathogenesis.

In attempt to develop an effective strategy to obtain douchi with anti-?-glucosidase functionality, Bacillus subtilis B2 was used as the initial microorganism to produce bacterial-type douchi koji capable of inhibiting ?-glucosidase activity in the current study. Various fermentation conditions, such as soybean type, fermentation time and humidity, resulted in different anti-?-glucosidase activity of the douchi koji. Regardless of soybean or black bean, the douchi koji exhibited a drastic increase in anti-?-glucosidase activity during the first 48 h of fermentation and kept a slight increase from 48 h to 96 h. The anti-?-glucosidase activities of both soybean and black bean kojis displaying the lowest at the relative humidity of 70 percent, rose up to the highest at the humidity of 90 percent and then showed a slight decrease. Under the same fermentation conditions, it is found that the soybean douchi koji exhibited higher ?-glucosidase inhibitory activity than that of black bean douchi koji. Maltose, sucrose and glucose were reduced drastically in soybean and black soybean koji after 96 h of fermentation. One of the most effective ?-glucosidase inhibitors, deoxynojirimycin (DNJ), with promising biological activity was observed both in the soybean koji and black soybean koji, which provide an inspiring strategy to produce DNJ-derived foods with low content of saccharides for the diabetic patients.

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