Functional characterization of the gene FoOCH1 encoding a putative α-1,6-mannosyltransferase in Fusarium oxysporum f. sp. cubense.

Fusarium oxysporum f. sp. cubense (FOC) is the causal agent of banana Fusarium wilt and has become one of the most destructive pathogens threatening the banana production worldwide. However, few genes related to morphogenesis and pathogenicity of this fungal pathogen have been functionally characterized. In this study, we identified and characterized the disrupted gene in a T-DNA insertional mutant (L953) of FOC with significantly reduced virulence on banana plants. The gene disrupted by T-DNA insertion in L953 harbors an open reading frame, which encodes a protein with homology to α-1,6-mannosyltransferase (OCH1) in fungi. The deletion mutants (ΔFoOCH1) of the OCH1 orthologue (FoOCH1) in FOC were impaired in fungal growth, exhibited brighter staining with fluorescein isothiocyanate (FITC)-Concanavalin A, had less cell wall proteins and secreted more proteins into liquid media than the wild type. Furthermore, the mutation or deletion of FoOCH1 led to loss of ability to penetrate cellophane membrane and decline in hyphal attachment and colonization as well as virulence to the banana host. The mutant phenotypes were fully restored by complementation with the wild type FoOCH1 gene. Our data provide a first evidence for the critical role of FoOCH1 in maintenance of cell wall integrity and virulence of F. oxysporum f. sp. cubense.

Pharmacokinetic Study of Ultrasmall Superparamagnetic Iron Oxide Nanoparticles HY-088 in Rats.

BACKGROUND AND OBJECTIVE: HY-088 injection is an ultrasmall superparamagnetic iron oxide nanoparticle (USPIOs) composed of iron oxide crystals coated with polyacrylic acid (PAA) on the surface. The purpose of this study was to investigate the pharmacokinetics, tissue distribution, and mass balance of HY-088 injection. METHODS: The pharmacokinetics of [55Fe]-HY-088 and [14C]-HY-088 were investigated in 48 SD rats by intravenous injection of 8.5 (low-dose group), 25.5 (medium-dose group), and 85 (high-dose group) mg/100 µCi/kg. Tissue distribution was studied by intravenous injection of 35 mg/100 µCi/kg in 48 SD rats, and its tissue distribution in vivo was obtained by ex vivo tissue assay. At the same time, [14C]-HY-088 was injected intravenously at a dose of 25.5 mg/100 µCi/kg into 16 SD rats, and its tissue distribution in vivo was studied by quantitative whole-body autoradiography. [14C]-HY-088 and [55Fe]-HY-088 were injected intravenously into 24 SD rats at a dose of 35 mg/100 µCi/kg, and their metabolism was observed. RESULTS: In the pharmacokinetic study, [55Fe]-HY-088 reached the maximum observed concentration (Cmax) at 0.08 h in the low- and medium-dose groups of SD rats. [14C]-HY-088 reached Cmax at 0.08 h in the three groups of SD rats. The area under the concentration-time curve (AUC) of [55Fe]-HY-088 and [14C]-HY-088 increased with increasing dose. In the tissue distribution study, [55Fe]-HY-088 and [14C]-HY-088 were primarily distributed in the liver, spleen, and lymph nodes of both female and male rats. In the mass balance study conducted over 57 days, the radioactive content of 55Fe from [55Fe]-HY-088 was primarily found in the carcass, accounting for 86.42 ± 4.18% in females and 95.46 ± 6.42% in males. The radioactive recovery rates of [14C]-HY-088 in the urine of female and male rats were 52.99 ± 5.48% and 60.66 ± 2.23%, respectively. CONCLUSIONS: Following single intravenous administration of [55Fe]-HY-088 and [14C]-HY-088 in SD rats, rapid absorption was observed. Both [55Fe]-HY-088 and [14C]-HY-088 were primarily distributed in the liver, spleen, and lymph nodes. During metabolism, the radioactivity of [55Fe]-HY-088 is mainly present in the carcass, whereas the 14C-labeled [14C]-HY-088 shell PAA is eliminated from the body mainly through the urine.

[Effect of combined drug treatment on megacolon with severe constipation].

OBJECTIVE: To assess the effectiveness of combined drug treatment on megacolon complicated by severe constipation. METHODS: Ten patients with megacolon confirmed by barium enema examination, 4 males and 6 females, aged 38 (15 - 66), with a mean course of 10 years (2 weeks - 23 years), all complicated by severe constipation and 5 cases with colonic obstruction confirmed by X-ray examination, 1 being diagnosed as with Hirschsprung' disease, 3 secondary to chronic constipation, 1 with diabetes mellitus, 1 with a history of anorectal malformation, 4 with colonic pseudo-obstruction, and 4 with colonic pseudo-obstruction, were treated with combined conservative therapy including tegaserod (6 mg 2/d), polyethylene glycol (PEG) 4000 (20 - 40 g/d), and liuweianxiao (traditional Chinese medicine, 5 # 3/d). Colon enema was used in the first week if necessary. Follow-up was conducted for 1 - 7 months. The major clinical data included bowel symptoms, complications and adverse effects. RESULTS: After 1 - 2 weeks of treatment, properties of feces, defecation times, defecation difficulty, and abdominal symptoms, and X-ray findings were all notably improved. No relapse of colonic obstruction was found. The 5 patients with colonic obstruction all showed release. Regarding adverse effect, mild diarrhea was found in 2 cases and was relieved when the dosage was decreased. CONCLUSION: Combined drug treatment including tegaserod, PEG 4000 and traditional Chinese medicine is effective in treating megacolon with severe constipation and may help avoid surgical treatment.

Hollow fiber membrane bioreactor affects microbial community and morphology of the DAMO and Anammox co-culture system.

Denitrifying anaerobic methane oxidation (DAMO) and Anammox co-culture system was investigated in hollow fiber membrane bioreactor (HfMBR) for the change of microbial community morphology and proportion. NO3--N and NH4+-N removal rates reached 85.33 and 37.95mg/L/d on 193d. The inoculum microorganisms were flocs and the proportion of DAMO archaea, DAMO bacteria and Anammox bacteria was 11.0, 24.2 and 0.4%, respectively, but it changed to 74.3, 11.8, 5.6% in HfMBR, respectively. Interestingly, microorganisms formed biofilms on fibers surface and the biofilms included two layers: inner layer was thin and dominated by DAMO bacteria and Anammox bacteria; while the outer layer was thick made up of granules with 100-200µm diameter and dominated by DAMO archaea. The spatial distribution of microorganisms in HfMBR was different from simulation results in the literature. Likely, HfMBR changed the interaction between DAMO and Anammox microorganisms, and the reactor configuration was beneficial for DAMO archaea growth.

[Molluscicidal effect of plastic film mulch covering method].

OBJECTIVE: To evaluate the molluscicidal effect of the plastic film mulch covering method. METHODS: In the barren land with a lot of Oncomelania hupensis snails, 3 experimental groups were set up, in which respectively using 3 different methods: a simple plastic film mulch covering method, film assisted with ammonium bicarbonate, and film assisted with amine molluscicide. In the canals, two experimental groups were set up, in which respectively using 2 different methods: simple plastic film mulch covering method and film assisted with ammonium bicarbonate. In above-mentioned areas, obstacles were cleared artificially. In each experiment group, 4 observation spots were set up, and 100 living snails were pot in each spot, and then, the plastic film mulch was evenly covered. The status of the snails was observed 3, 7, 15 and 30 days after the intervention. RESULTS: In the barren land, the snail death rates of the simple plastic film group were 20.77% and 96.92% 15 days and 30 days after the intervention, respectively. The snail death rate of the film assisted with amine molluscicide group was 80.46% 3 days after the intervention. In all the experiment groups, the snail death rates were from 96.92 to 100% 30 days after the intervention. CONCLUSION: The plastic film mulch covering method has a great molluscicide effect in the hill subtype and water network type of schistosomiasis epidemic areas.