Regional epidemic laws of poplar Ice Nucleation Active bacterial canker

Through the methods of correlation analysis and main factor analysis, the relationship between the poplar INA bacte-rial canker and circumstances was analyzed and 9 main factors for affecting the disease were selected. Based on the compre-hensive analysis of main factors and induced factors, the standard for risk grades of this disease was promoted and northeast region of China was divided into 4 districts with different risk grades: seriously occurring district, commonly occurring district, occasionally occurring district, and un-occurring district. Nonlinear regression analysis for six model curves showed that the Richard growth model was suitable for describing the temporal dynamics of poplar INA bacterial canker. By stepwise variable selection method, the multi-variable linear regression forecasting equation was set up to predict the next year抯 disease index, and the GM (1,1) model was also set up by grey method to submit middle or long period forecast.

Extended activated sludge model no. 1 (ASM1) for simulating biodegradation process using bacterial technology

Phosphorus is one of the most important nutrients required to support various kinds of biodegradation processes. As this particular nutrient is not included in the activated sludge model no. 1 （ASM1）, this study extended this model in order to determine the fate of phosphorus during the biodegradation processes. When some of the kinetics parameters are modified using observed data from the restoration project of the Xuxi River in Wuxi City, China, from August 25 to 31 in 2009, the extended model shows excellent results. In order to obtain optimum values of coefficients of nitrogen and phosphorus, the mass fraction method was used to ensure that the final results were reasonable and practically relevant. The temporal distribution of the data calculated with the extended ASM1 approximates that of the observed data.

Effects of dietary supplementation with tropical microfungi Mucor circinelloides and Trichoderma harzianum powder on growth performance,bacterial communities,and the biomass nutritional profile of white shrimp grow-out culture(Litopenaeus vannamei)

Microfungi have been explored further as supplement constituents in shrimp culture due to their rich protein,lipid,essential amino acids,fatty acids,and various bioactive compounds.The researchers have evaluated the effects of two microfungi powders(Mucor circinelloides and Trichoderma harzianum)as feed supplements on growth performance,bacterial communities,and the biomass nutritional profile of white shrimp(Litopenaeus vannamei).The results showed that commercial/artificial feed(Feng-Li)with supplementation microfungi powder had a different effect on white shrimp growth performance than control after 62 days of the grow-out period.Supplementation with 1.5%M.circinelloides powder(M-2)could improve the growth performance of white shrimp,especially the survival rate(81.33%),final body weight(5.21 g),and shrimp biomass(211.35 g).In contrast,supplementation with 1.5%T.harzianum powder(T-2)did not improve the growth performance of white shrimp compared to control(p>0.05).Furthermore,it also affected the profile of the bacterial community in culture water as well as in shrimp intestines.Supplementation with both microfungi could reduce the total number of bacteria in culture water at the end of the experiment,where the lowest number was obtained in treatment T-2(3.9×10^(5)CFU/mL),followed by M-2(9.9×10^(5)CFU/mL)and control(4.4×10^(6)CFU/mL).In the culture water,20 isolates of culturable bacteria were found during the trial,with the dominant bacteria in M-2:Bacillus cereus,Bacillus velezensis,Gordonia polyisoprenivorans,T-2:Acinetobacter sp.,Gordonia polyisoprenivorans,Micrococcus luteus.Based on average well colour development(AWCD),the highest bacterial activity was in the M-2(0.297-0.707),followed by T-2(0.226-0.717)and control(0.094-0.694).The highest substrate group utilised in M-2 and T-2 were polymers(0.896 and 1.348)and control:amines(0.100).The highest Shannon diversity index was obtained in the M-2(2.508),followed by control(2.286)and the T-2(2.157).As many as 11 isolates of culturable bacteria were found in the shrimp intestine,with dominant bacteria in M-2:Bacillus velezensis,Micrococcus luteus,Bacillus cereus,T-2:Bacillus velezensis,Micrococcus sp.2,Demequina activiva.The highest bacterial activity was in M-2(2.259),followed by control(2.020)and T-2(0.050).The highest substrate group utilisation was in M-2:polymers(2.564),T-2:carbohydrates(0.094),and control:polymers(2.185).The highest Shannon diversity index was in the M-2(3.234),followed by control(3.230)and the T-2(0.751).In addition,1.5%M.circinelloides and T.harzianum supplementation increased white shrimp muscle protein content up to 79.21%and 80.40%,respectively,compared to control(76.73%).In conclusion,using Mucor circinelloides powder as a feed supplement can improve the growth performance of white shrimp,increase the functional/probiotic bacteria:B.cereus and B.velezensis in cultur and shrimp’s intestine,and increase the protein content in shrimp muscle tissue.However,more in-depth research is needed,especially on anti-nutritional compounds from fungi that affect shrimp growth.

Nitrous oxide concentration and nitrification and denitrification in Zhujiang River Estuary,China

The concentrations of nitrous oxide varies between 57 and 329 nmol/dm3, saturation is 674%～4 134% in the Zhujiang River Estuary. This suggests that the area is an emissive source of nitrous oxide. The acetylene inhibition technique is employed to evaluate the rates of nitrification, denitrification and nitrate reduction by bacterial activities in the sediments at three sites. The average of nitrification, denitrification and nitrate reduction rates ranges from 0.32 to 2.43, 0.03 to 0.84 and 4.17 to 13.06 mmol/(m2·h), respectively. The ver- tical profiles of the sediments show that the nitrification and denitrification processes mainly take place in the depth from 0 to 4 cm and depend on regional conditions. The rates of nitrification, denitrification and nitrate reduction are dominated by Eh, nitrate and ammoni- um concentrations in sediments and DO in overlay water. There is a coupling between nitrification and denitrification.

Effect of low-temperature treatment on bacterial cultivation in bacterial induced mineralization

In this paper,the effect of low-temperature treatment on bacterial activity was investigated and its performance in preparing the consolidated sand was accessed.Four factors,including absorbance(OD600),p H,electric conductivity(EC)and urease activity(UA)were monitored to evaluate the bacterial activity.Moreover,the calcium carbonate yields under different bacterial solution and cementation solution volume ratios were determined.Finally,the compressive strength and microstructure of consolidated sand were investigated and the mechanism was explored by characterising the products among sand particles.The results showed that for both continuous and interval cultivation of bacteria,stable bacterial solution was harvested within the cultivation period of 30 h.Low-temperature treatment showed limited inhibition at early cultivation stage,while it had strong inhibition at middle cultivation stage.The interval cultivation improved the cultivation efficiency of bacteria.It was observed that the low-temperature preservation for a stable bacterial solution has little influence on UA before 4 days,while UA decreased seriously after its preservation time was extended to over 8 days.The optimal volume ratio of bacterial solution and substrate solution was 1:1,resulting in the highest calcium carbonate yield.The improved compressive strength of consolidated sand after 3 injections was attributed to the irregular-shaped calcite products,which coated and bonded the sand grains together.

Impact of preozonation on the bioactivity and biodiversity of subsequent biofilters under low temperature conditions-- A pilot study

The combination of preozonation and subsequent biological granular activated carbon （O3/BAC） filtration is well known as a promising method for the removal of many pollutants. Temperature and nutrients are the dominant factors in external conditions to influence the biological communities. To explore the influence of preozonation under low temperature, the factors such as dissolved oxygen （DO）, dissolved organic carbon （DOC） and NH4^＋-N were analyzed from the sampling ports every week; triphenyl tetrazolium ehloride-dehydrogenase activity （TTC-DHA） and the nitrifying activity were detected along the bed height ofbiofilter at four levels （10. 40. 70 and i 10 cm） on the 90th, 110th, and 130th day; ~nicrobial community, based on 16S rRNA gene-denaturing gradient gel electrophoresis （DGGE）, was monitored on the 130th day of the operation. The observed microbial property showed that preozonation had a positive influence on bioactivity, biomass and nitrifying activity. Community analysis showed no significant difference on the biodiversity of nitrifying bacteria between the parallel filters in the inlet end based on the method employed. This result showed that biofilters＇ performance is not correlated well with microbial biodiversity. The elevated functionality in O3/BAC filters can be a result of increased microbial activity, which was promoted by preozonation.

A substitution mutation in OsPELOTA confers bacterial blight resistance by activating the salicylic acid pathway

We previously reported a spotted-leaf mutant pelota（originally termed HM_（47）） in rice displaying arrested growth and enhanced resistance to multiple races of Xanthomonas oryzae pv. oryzae. Here, we report the mapbased cloning of the causal gene OsPELOTA（originally termed spl^（HM47））. We identified a single base substitution from T to A at position 556 in the coding sequence of OsPELOTA, effectively mutating phenylalanine to isoleucine at position 186 in the translated protein sequence. Both functional complementation and over-expression could rescue the spotted-leaf phenotype. OsPELOTA, a paralogue to eukaryotic release factor 1（eRF_1）, shows high sequence similarity to Drosophila Pelota and also localizes to the endoplasmic reticulum and plasma membrane.OsPELOTA is constitutively expressed in roots, leaves,sheaths, stems, and panicles. Elevated levels of salicylic acid and decreased level of jasmonate were detected in the pelota mutant. RNA-seq analysis confirmed that genes responding to salicylic acid were upregulated in the mutant. Our results indicate that the rice PELOTA protein is involved in bacterial leaf blight resistance by activating the salicylic acid metabolic pathway.

Bacterial communities in different locations, seasons and segments of a dairy wastewater treatment system consisting of six segments

A dairy wastewater treatment system composed of the 1st segment（no aeration） equipped with a facility for the destruction of milk fat particles, four successive aerobic treatment segments with activated sludge and a final sludge settlement segment was developed. The activated sludge is circulated through the six segments by settling sediments（activated sludge） in the 6th segment and sending the sediments beck to the 1st and 2nd segments.Microbiota was examined using samples from the non-aerated 1st and aerated 2nd segments obtained from two farms using the same system in summer or winter. Principal component analysis showed that the change in microbiota from the 1st to 2nd segments concomitant with effective wastewater treatment is affected by the concentrations of activated sludge and organic matter（biological oxygen demand [BOD]）, and dissolved oxygen（DO） content. Microbiota from five segments（1st and four successive aerobic segments） in one location was also examined. Although the activated sludge is circulating throughout all the segments, microbiota fluctuation was observed. The observed successive changes in microbiota reflected the changes in the concentrations of organic matter and other physicochemical conditions（such as DO）, suggesting that the microbiota is flexibly changeable depending on the environmental condition in the segments. The genera Dechloromonas, Zoogloea and Leptothrix are frequently observed in this wastewater treatment system throughout the analyses of microbiota in this study.

Potential acute effects of suspended aluminum nitride (AlN) nanoparticles on soluble microbial products (SMP) of activated sludge

The study aims to identify the potential acute effects of suspended aluminum nitride（Al N）nanoparticles（NPs） on soluble microbial products（SMP） of activated sludge.Cultured activated sludge loaded with 1,10,50,100,150 and 200 mg/L of Al N NPs were carried out in this study.As results showed,Al N NPs had a highly inverse proportionality to bacterial dehydrogenase and OUR,indicating its direct toxicity to the activated sludge viability.The toxicity of Al N NPs was mainly due to the nano-scale of Al N NPs.In SMP,Al N NPs led to the decrease of polysaccharide and humic compounds,but had slight effects on protein.The decrease of tryptophan-like substances in SMP indicated the inhibition of Al N NPs on the bacterial metabolism.Additionally,Al N NPs reduced obviously the molecular weight of SMP,which might be due to the nano-scale of Al N.