Marker‐assisted breeding for improvement of anaerobic germination in japonica rice (Oryza sativa)

Direct seeding is increasingly being practiced in rice cultivation areas because it saves labour and reduces cost of production and management. In this study, four japonica‐type breeding lines were developed from a cross of a japonica cultivar and an AG‐tolerant donor, KHO, using marker‐assisted selection. Validation of the target genes AG1 and AG2 in the selected lines was examined by PCR analysis and the background recovery rate by the recurrent parent was confirmed by genotyping using a 6K SNP chip. Compared to the recurrent, the survival rates of the selected lines were improved in a range from 33% to 115% in three conditions; in particular, the survival rate was increased in more than twice that of the recurrent parent under the hypoxic condition. The main agronomic trait, yield and quality‐related traits were similar to those of the recurrent parent. The use of these lines will contribute to the expansion of the cultivation area due to the proven economic benefits of direct seeding in Korea.     

The use of dialysis cells for investigating pore water composition in wetland substrata,with particular reference to dissolved iron and sulphide

Abstract

Details and some evaluation are given of the use of a dialysis method for sampling pore water from depth in wetland substrata (peats), with particular reference to measurement of concentrations of ion species with stabilities dependent on redox potential. The method is based upon the burial and subsequent retrieval (after equilibration) of cells made from dialysis membrane filled with deionized water. Preliminary results of field investigations of concentrations of dissolved iron and sulphide in the pore water of base‐rich mires, as sampled by this method, are given. Results suggest that the method could have very considerable application and that its potential, and possible problems, deserve further examination.     

Bacterial infection of the lower respiratory tract in 34 horses

OBJECTIVE: To investigate associations between the bacteriology and aspects of history, clinical presentation, outcome and pathology of lower respiratory tract disease of 34 horses. PROCEDURE: Detailed aerobic and anaerobic bacteriological investigations were performed on clinical specimens from horses with pneumonia, lung abscessation and necrotic pneumonia with or without pleurisy in an attempt to identify those bacteria that might contribute to the initiation and progression of infection. RESULTS: Bacteria were cultured from 33 of the 34 horses. In ten cases, only aerobic/facultatively anaerobic isolates were cultured while aerobic/facultatively anaerobic bacteria and obligately anaerobic bacteria were isolated in the other 23 cases. Moderate to large numbers of anaerobic bacteria were isolated only when the estimated duration of illness was at least five days. Bacteria were not cultured from 12 of the pleural fluid samples but were always cultured from pulmonary samples (either transtracheal aspirates from live horses or pulmonary lesions at necropsy). Streptococcus equi subsp zooepidemicus was isolated in the three cases where only one bacterial species was cultured. In the other 30 cases, multiple species were isolated. These included most often and in greatest numbers, Streptococcus equi subsp zooepidemicus, Pasteurellaceae, Escherichia coli, anaerobic cocci, Eubacterium fossor, Bacteroides tectum, Prevotella heparinolytica, Fusobacterium spp, and pigmented members of the genera Prevotella and Porphyromonas. Aerobic/facultatively anaerobic organisms were isolated from 97% of horses, while obligately anaerobic organisms were cultured from 68% of horses. CONCLUSION: There was no association between the isolation of any specific bacterium and the outcome of disease. However, obligately anaerobic bacteria (such as anaerobic cocci, Bacteroides tectum, P heparinolytica and Fusobacterium spp) and the facultatively anaerobic species Escherichia coli, were recovered more commonly from horses that died or were euthanased than from those that survived. There was an association between failure of horses to recover from pleuropneumonia and delay in diagnosis and initiation of treatment.     

驱除瘤胃真菌对绵羊瘤胃内纤维物质降解的影响

选取3只体况良好,带有永久性瘤胃瘘管的蒙古羊与小尾寒羊的杂交一代公羊,运用尼龙袋法研究全部驱除瘤胃真菌对绵羊瘤胃内稻草纤维物质降解的影响.结果表明：全部驱除瘤胃厌氧真菌后,改变了瘤胃内纤维物质的降解动力学参数,显著降低了瘤胃内稻草DM、NDF、ADF的降解速率（P＜0.05）,显著提高了三者的消化延滞时间（P＜0.05）,显著降低了稻草NDF、ADF的降解率,而DM的降解率有所降低,但差异不显著（P＞0.05）.说明瘤胃真菌在纤维物质降解中发挥了重要的作用.     

Differential ability of alcohol fermentation between the seeds of flooding-tolerant and flooding-susceptible varieties of Echinochloa crus-galli (L.) Beauv.

Seed germination and respiratory metabolism under aerobic and anaerobic conditions were studied in the flooding-tolerant and flooding-susceptible varieties of Echinochloa crus-galli with an identical genome and common ancestry . In the flooding-tolerant E. crus-galli var. formosensis , the seeds imbibed under nitrogen could germinate and exhibited an I/N quotient > 0.6. They accelerated glycolysis and concomitantly produced large and equimolar quantities of carbon dioxide and ethanol, suggesting that the seeds of this variety showed operation of the Pasteur effect and respired through alcohol fermentation under anaerobic conditions. The seeds excreted most of the toxic fermentation product. In contrast, the seeds of the flooding-susceptible E. crus-galli var. praticola were capable of germinating only under aerobic conditions through the conventional aerobic respiration and were unable to anaerobically respire to germinate through alcohol fermentation regardless of the presence of both sufficient alcohol dehydrogenase activity and a high redox charge of the pyridine nucleotides.     

Innovative liquid formulation of digestates for producing a biofertilizer based on Bacillus siamensis: Field testing on sweet pepper

A biofertilizer (BF) based on the plant growth promoting rhizobacterium (PGPR) Bacillus siamensis was produced using anaerobic digestate (AD) as the main ingredient of the growth medium, alongside a carbon source from residual origin. The use of residues for the growth of PGPR reduces the production costs of biofertilizers, but makes an assessment of the possible toxicity of residues for the bacteria or plants necessary. Therefore, the growth medium of PGPR was first optimized using the response surface methodology (RSM), followed by phytotoxicity tests and a field trial of the BF in a sweet pepper (Capsicum annuum L.) crop at two different locations. AD at 50% dilution, supplemented with 2.3% sugar beet molasses, was the optimum growth medium for producing the BF, with a bacterial concentration of 10⁹ cfu mL⁻¹. In the field trial, the treatments inoculated with BF and fertilized with decreased mineral N (80%) produced significantly better yields per ha than the controls with decreased N (80%) and full N (100%) without BF. This indicates improved efficiency of N use by the crop, as a consequence of the use of BF.     

Collection,Analysis, and Utilization of Biogas from Anaerobic Treatment of Crab Processing Waters

Abstract

Two laboratory-scale, upflow anaerobic reactors were constructed to treat blue crab (Callinectes sapidus) cooking wastewater for determination of the volume and composition of the resulting bio-gas. Both systems (A and B) consisted of two 4-liter (L) upflow anaerobic reactors and one 8-L aerobic reactor in series. The first anaerobic reactor of System A contained 240,12.7 mm foam cubes, while the first anaerobic reactor of System B contained 180 foam pieces (25.4 ×25.4 ×12.7 mm). Biogas production rates for System A ranged from 6.6 L gas/L feed to 10.0 L gas/L feed. Mean values for System B ranged from 7.1 L gas/L feed to 11.9 L gas/L feed. Methane and carbon dioxide comprised 68% and 28%, respectively, of the gas from both systems. Hydrogen sulfide averaged 1.5% and 1.4% for systems A and B, respectively. A pilot-scale biogas collection and utilization system was also constructed and successfully demonstrated. Details of the pilot-scale system design are provided in the paper to help processors better understand how the technology might be applied.     

竹鼠肠道中厌氧纤维素降解菌的分离与鉴定

本试验旨在从竹鼠肠道中分离厌氧纤维素降解菌并鉴定。取中华竹鼠盲肠内容物稀释,采用含2种不同纤维素[微晶纤维素(MCC)和羧甲基纤维素钠(CMC-Na)]的培养基在厌氧条件下对纤维素降解菌进行初筛,后又经以纤维二糖为唯一碳源的培养基的多次复筛,选出的菌株进行经形态学和分子生物学的鉴定。结果表明:经过初筛和复筛,筛选出了2株厌氧纤维素降解菌。初筛培养基采用MCC和CMC-Na最终筛选出的2株纤维素降解菌的纤维素酶活力分别为6.599和5.268U/m L。菌株经PCR鉴定、测序,用所得序列构建系统发育树,得出这2株菌与酪酸梭状芽孢杆菌(Clostridium butyricum)具有很高的同源性,达99%,二者均属于梭菌属(Clostridium)。本试验从竹鼠盲肠中成功筛选出2株纤维素降解菌,经鉴定确定属于梭菌属。     

干法厌氧发酵装备同步升温发酵及微生态网络研究

干法厌氧发酵是提高农业农村废弃物处理效率及资源高效循环的重要技术之一。先前围绕该技术产甲烷效率低、传质传热不均匀等问题,提出了微好氧同步预升温干发酵技术,设计了配套装备,开展了小试和中试试验,产甲烷效率得到改善。为进一步提高放大装备的实际应用质量,在对发酵装置密封、进出料、喷淋循环系统等关键部件优化的基础上,探明了最优曝气量及实际应用中微好氧预升温阶段物质转化特性,揭示了微生物生态网络关系,评价了实际运行效果。结果表明：对关键部件的优化显著提升装备运行稳定性,微好氧同步预升温阶段最优曝气量为10 L/min,容积产气率达到1.20 m³/(m³·d)。物料在第40小时升温至42℃,曝气组各层物料温度较未曝气组均提高45.54%、32.46%和52.06%。同步预升温促进了物料各层纤维素和半纤维素的降解,提高了酸化效率,有机酸质量浓度分别提高59.83%、50.69%和20.85%,物料产气潜力提高34.9%。探明了微生物网络关系以及与发酵环境因子变化的相关性,发现微好氧预升温阶段具有协同作用的功能微生物SBR1031、Synergistale...     

酒糟厌氧消化产甲烷特性与微生物菌群结构分析

酒糟是酿酒生产过程中的副产物,以酒糟为研究对象,分别考察不同底物总固体（Total solid, TS）质量分数（0.5%、1%、1.5%、2%）、接种比（接种污泥与酒糟的挥发性固体质量比）（0.25、0.5、0.75、1、1.5）和温度（25、37、50℃）条件下酒糟的厌氧消化产甲烷特性。结果表明,随着TS浓度的增加,产甲烷量逐渐增加, 2%TS条件下可获得最大的累计产沼气量（532.8mL/g）和产甲烷量（294.7mL/g）。接种比是影响厌氧消化系统的重要因素,随着接种比的增大,系统累计产沼气和产甲烷量呈先增加后减少的趋势,在接种比为0.25和0.5的条件下,系统发生崩溃,并未产甲烷,当接种比为1时,获得最大的累计产沼气和甲烷量。当TS质量分数为2%、接种比为1.5、发酵温度为50℃的条件下,获得最大的累计产沼气量为559.4mL/g,相较37℃条件下提高了10.2%,而获得的累计产甲烷量为284.0mL/g,相较37℃并未显著提升（P>0.05）。利用修正的Gompertz模型进行产气动力学分析后,发现TS质量分数越高、接种比越大、温度越高,产甲烷迟滞期越短。同时对不同温度反应体系中的微生物群落进行了分析,发现Bacteroidetes和 Firmicutes为优势菌门,随着温度的升高,产甲烷菌逐渐由氢营养型代替乙酸营养型。因此, TS浓度、接种比和温度是厌氧发酵重要因素,初步确定2%TS、接种比为1的中温酒糟厌氧发酵产甲烷性能相对较好。