Survival of pathogenic bacteria in compost with special reference to Escherichia coli

Application of compost in agricultural practice could potentially cause contamination of foodstuffs with pathogenic bacteria such as Escherichia coli O157：H7 （E. Coli O157）. We investigated pathogenic bacteria in compost collected from the compost facilities, and evaluated the survival of E. coli K12 and O157 in laboratory experiments. Out of 19 compost product samples, coliform bacteria and salmonella were detected in 7 and 3 samples respectively. The number of coliform bacteria was 1.8 × 10^2 to 2.5 × 10^6 CFU/g dw and that of salmonella was 4.2 × 10^1 to 6.0 × 10^3 CFU/g dw. Moreover. coliform bacteria, fecal coliform, E. coli and salmonella were detected during composting at 54℃ to 67℃. The results indicated that moisture content was a very important factor to the heat sensitivity of pathogenic bacteria in compost, E. coli in compost of high moisture content was more sensitive than that in compost of low moisture content, cells harvested in logarithmic phase was more sensitive than these in stationary phase, and E. coli K12 was more sensitive than E. coli O157. Based on the D values, the lethal time of E. coli K12 and 0157 from 10^8 to 10^0 CFU/g dw were 16.3 and 28.8 min, respectively, at 60℃ in compost with 40% moisture content. However, some E. coli cells survived in composting process at 54℃ to 67℃. Water potential（low moisture content） and physiological aspects of bacteria（stationary phase） could explain only in part of the prolonged survival of E. coli in compost, and there should be some other factors that are conducive to bacterial survial in compost.

Isolation and structural elucidation of antifungal compounds from Curcuma amada

Objective: To isolate and identify the antifungal compounds from Curcuma amada. Methods: The antifungal activity was measured by the diameter of colonies grown on Petri dish,microscopic observation,and CLSI microdilution methods. The antifungal compounds were isolated through bioactivity guided purification by using silica gel and high-performance liquid chromatography. Structural identification of the antifungal compounds was conducted using 1 H NMR,13 C NMR,and liquid chromatography-tandem mass spectrometry. Results: The purified antifungal compounds were zederone and furanodienone. These two compounds showed dose-dependent antifungal activity against Fusarium solani sensu lato. The concentration required for 50% growth inhibition(IC50) of FSSL ranged from 115 to 129 μM and 82 to 91 μM for zederone and furanodienone,respectively. Conclusion: This study suggested that the isolated compounds from Curcuma amada could be promising natural antifungal agents to control the diseases caused by Fusarium solani sensu lato.

Development of Hydropriming Techniques for Sowing Seeds of Upland Rice in Uganda

Hydropriming is one of the presoaking, seed priming technique that allows seeds to imbibe water and go through the first stage of germination but does not allow radicle appearance. After water imbibition, seeds are dried to their original weight. This technique is used to help crops overcome environment stress. This study aims to assess the morphological traits of farmer’s seeds for developing priming treatments so as to develop appropriate methods to maximize the effect of hydropriming. We collected farmer’s samples of rice sowing seeds grown indifferent regions of Ugandan. For each sample, distribution of the seed density in percentages was calculated. Secondly, germination tests as per seed density levels and as per farmer’s seed samples were conducted for deciding appropriate priming treatment. Finally, wooden boxes experiment was conducted to confirm priming effects. As the result, it was observed that the difference in seed density levels affects the quality of farmer’s seeds, as observed in the case of NERICA4. If the radicle appears during soaking period, the newly developed radicle dies during the seed drying process in the hydropriming treatment. Seed germination was observed after 24 h of sowing at room temperature, even at a seed density level of 1.17, which is vigorous for germination. Consequently, farmer’s seeds were soaked for 24 h to promote water absorption and activate metabolic pathways and to avoid germination failure when seeds are dried to their initial weight. After hydropriming treatment, plant growth was improved. Alternatively, significant difference was not observed in the mean emergence time between hydroprimed and unprimed seeds. These results suggest that priming the seeds by soaking for 24 h and drying to their initial weight considerably affects initial growth after emergence under dry soil condition.

Inhibitory effect of blue honeysuckle extract on high-fat-diet-induced fatty liver in mice

Blue honeysuckle is rich in polyphenols, and recently receiving attention because of its potential antioxidant and anti-inflammatory properties. Nonalcoholic fatty liver disease(NAFLD) is the leading cause of chronic liver disease that develops hepatic inflammation and metabolic syndrome. The present study aims to study the effect of blue honeysuckle extract(BHE) on fat deposition and hepatic lipid peroxidation in a high-fat-diet(HFD)-induced mouse model. Mice were fed a normal diet(ND) or a HFD containing 0.5% or 1% of BHE or not for 45 d. Liver sections were stained by hematoxylin-eosin staining.Serum lipids were measured by a clinical analyzer. Insulin was examined by ELISA, and hepatic proteins were detected by Western blotting. Dietary supplementation of BHE dose-dependently suppressed HFD-induced obesity and hepatic fat deposition. Moreover, BHE improved glucose metabolism by increasing insulin sensitivity and attenuated oxidative stress potentially by up-regulating nuclear factor(erythroid-derived 2)-like 2(Nrf2)-mediated pathway.

Systemic RNAi of V-ATPase subunit B causes molting defect and developmental abnormalities in Periplaneta fuliginosa

The vacuolar (H+)-ATPases (V-ATPases) are ATP-driven proton pumps with multiple functions in many organisms. In this study, we performed structural and functional analysis of vha55 gene that encodes V-ATPase subunit B in the smokybrown cockroach Periplaneta fuliginosa (Blattodea). We observed a high homology score of the deduced amino acid sequences between 10 species in seven orders. RNAi of the vha55 gene in R fuliginosa caused nymphal/nymphal molting defects with incomplete shedding of old cuticles, growth inhibition, as well as bent and wrinkled cuticles of thoraxes and abdominal segments. Since growth inhibition caused by vha55 RNAi did not interfere in the commencement of cockroach molting, molting timing and body growth might be controlled by independent mechanism. Our study suggested V-ATPases might be a good candidate molecule for evolutionary and developmental studies of insect molting.