Immunolocalization of hemicelluloses in Arabidopsis thaliana stem. Part I: temporal and spatial distribution of xylans

We investigated the microdistribution of xylans in different cell types of Arabidopsis stem using immunolocalization methods with LM10 and LM11 antibodies. Xylan labeling in xylary fibers (fibers) was initially detected at the cell corner of the S(1) layer and increased gradually during fiber maturation, showing correlation between xylan labeling and general secondary cell wall formation processes in fibers. Metaxylem vessels (vessels) showed earlier development of secondary cell walls than fibers, but revealed almost identical labeling patterns to fibers during maturation. No difference in labeling patterns and intensity was detected in the cell wall of fibers, vessels and protoxylem vessels (proto-vessels) between LM10 and LM11, indicating that vascular bundle cells may be chemically composed of a highly homogeneous xylan type. Interestingly, interfascicular fibers (If-fibers) showed different labeling patterns between the two antibodies and also between different developmental stages. LM10 showed no labeling in primary cell walls and intercellular layers of If-fibers at the S(1) formation stage, but some labeling was detected in middle lamella cell corner regions at the S(2) formation stage. In contrast, LM11 revealed uniform labeling across the If-fiber cell wall during all developmental stages. These results suggest that If-fibers have different xylan deposition processes and patterns from vascular bundle cells. The presence of xylan was also confirmed in parenchyma cells following pectinase treatment. Together our results indicate that there are temporal and spatial differences in xylan labeling between cell types in Arabidopsis stem. Differences in xylan labeling between Arabidopsis stem and poplar are also discussed.     

Two cellulolytic Clostridium species: Clostridium cellulosi sp. nov. and Clostridium cellulofermentans sp. nov.

Two cellulolytic clostridia, one thermophilic and the other mesophilic, were isolated and characterized. Cells of the thermophile are gram-negative rods that are motile with lophotrichous flagella and spherical terminal endospores which swell the cells. The optimum growth temperature is 55 to 60 degrees C, with a range of 40 to 65 degrees C. The deoxyribonucleic acid composition is 35 mol% G + C. The name Clostridium cellulosi sp. nov. is proposed. The type strain is AS 1.1777. Cells of the mesophile are gram negative and motile with peritrichous flagella and terminal oval or spherical spores which swell the cells. The deoxyribonucleic acid composition is 34 mol% G + C. The name Clostridium cellulofermentans sp. nov. is proposed. The type strain is AS 1.1775. Both C. cellulosi AS 1.1777 and C. cellulofermentans AS 1.1775 are deposited in the China Committee for Culture Collection of Microorganisms, Institute of Microbiology, Academia Sinica, Beijing, People's Republic of China.     

Biohydrogenation of linoleic acid by Clostridium sporogenes, Clostridium bifermentans, Clostridium sordellii and Bacteroides sp.

Abstract Several strains of Clostridium bifermentans, Clostridium sporogenes and Clostridium sordellit and one strain of Bacteroides sp. hydrogenate linoleic acid into transvaccenic acid in vitro following the same pathway. Linoleic acid (18:2; 9- cis , 12- cis ) was first isomerised into 9- cis , 11- trans -octadecadienoic acid, after which the 9- cis double bond was reduced. These species also hydrogenated linoleic acid into an octadecenoic acid in vivo when mono-associated with gnotobiotic rats. Several other species of Clostridium and Bacteroides did not hydrogenate linoleic acid.     

Heterogeneity of enterotoxin-like protein extracted from spores fo Clostridium perfringens type A.

Enterotoxin-like protein was extracted from spores of three enterotoxin-positive and three enterotoxin-negative strains of Clostridium perfringens type A by urea/mercaptoethanol, alkaline mercaptoethanol and alkaline dithiothreitol. Disc immunoelectrophoresis demonstrated that three distinct enterotoxin-like proteins could be extracted. In 7% acrylamide gels, type I, type II, and type III enterotoxinlike proteins had relative mobilities of 0.52, 0.63, and 0.73 respectively. In contrast to disc immunoelectrophoresis, immunoelectrophoresis in agar gel demonstrated identical electrophoretic properties for the various entertoxin-like proteins. Immunoelectrofocusing experiments gave isoelectric points of 4.43, 4.43, 4.36, and 4.52 for purified entertoxin and type I, type II, and type III enterotoxin-like proteins respectively. Ferguson plots (i.e., log relative mobility versus acrylamide concentration) yielded nonparallel lines which intersected at a nonsieving concentration of acrylamide indicating that the various species of enterotoxin-like protein differed in size. Estimation of the molecular weight of purified enterotoxin and the three species of enterotoxin-like protein was done by comparing the slopes obtained in Ferguson plots with those obtained using proteins of a known molecular weight. Molecular weights of 38000, 36500, 23000, and 15400 were obtained for purified enterotoxin, type I, type II, and type III enterotoxin-like protein respectively. Collectively, the evidence indicates that fractionation of the different species of enterotoxin-like protein was due primarily to differences in their size, and that different forms of enterotoxin-like protein can be extracted from spores of different strains of C. perfringens type A.     

A rapid method for the screening of plasmids from Clostridium acetobutylicum and other Clostridium sp.

Summary A rapid method was developed for plasmid DNA screening from micro volume cultures of Clostridium acetobutylicum. It involves protoplastization by lysozyme, nuclease inhibition by incorporating EDTA or DEP, followed by lysis with high concentration of SDS. The whole lysate is applied directly to electrophoretic analysis.     

Degradation of chlorinated hydrocarbons by Clostridium sp. isolated from lindane-amended,flooded soil

Summary A Clostridium sp., isolated from flooded soil amended with lindane (γ-BHC), decomposed methoxychlor, γ-BHC and heptachlor in that order under anaerobic condition. During the bacterial degradation of ring-labelled C¹⁴-γ-BHC, there was a net loss of radioactivity from the reaction mixture. Release of C¹⁴O₂ during the degradation of C¹⁴-γ-BHC was negligible. Methane was not detected as an end product of γ-BHC breakdown. re]19720406     

The reduction of nitrate to ammonium by a Clostridium sp. isolated from soil

Cultures of Clostridium KDHS2 reduced 15NO3- to 15NH4+ with a concurrent increase in molar growth yield of 15.7% compared with fermentatively grown bacteria. The bacteria exhibited a Ks (NO3-) of 0.5 mM and reduced NO3- maximally at a rate of 0.1 mumol h(-1) mg dry wt)-1. A partially purified nitrate reductase was obtained which had a Km (NO3-) of 0.15 mM. The reduction of 13NO3- to 13NH4+ by resting bacteria was not inhibited by NH4+, glutamate, glutamine, methionine sulphoximine or azaserine. Glutamine synthetase affected neither the synthesis nor the activity of the NO3(-)-reducing enzymes. The results are consistent with the hypothesis that NO3- reduction to NH4+ in this Clostridium sp. is dissimilative. SO32-, but not SO42-, inhibited the reaction, apparently at the level of NO2- reduction.     

Biotransformation of CL-20 by a dehydrogenase enzyme from Clostridium sp. EDB2

In a previous study, a marine isolate Clostridium sp. EDB2 degraded 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) under anaerobic conditions (Bhushan B, Halasz A, Thiboutot S, Ampleman G, Hawari J (2004c) Chemotaxis-mediated biodegradation of cyclic nitramine explosives RDX, HMX, and CL-20 by Clostridium sp. EDB2. Biochem Biophys Res Commun 316:816–821); however, the enzyme responsible for CL-20 degradation was not known. In the present study, we isolated and purified an enzyme, from strain EDB2, responsible for CL-20 degradation. The enzyme was membrane-associated and NADH-dependent and had a molecular weight of 56 kDa (with SDS-PAGE). N-terminal amino acid sequence of enzyme revealed that it belonged to dehydrogenase class of enzymes. The purified enzyme degraded CL-20 at a rate of 18.5 nmol/h mg protein under anaerobic conditions. Carbon and nitrogen mass balance of the products were 100 and 64%, respectively. In LC–MS–MS studies, we detected three different initial metabolites from CL-20, i.e., mono-nitroso derivative, denitrohydrogenated product, and double-denitrated isomers with molecular weight of 422, 393, and 346 Da, corresponding to presumed empirical formulas of C₆H₆N₁₂O₁₁, C₆H₇N₁₁O₁₀, and C₆H₆N₁₀O₈, respectively. Identity of all the three metabolites were confirmed by using ring-labeled [¹⁵N]CL-20 and the nitro-group-labeled [¹⁵NO₂]CL-20. Taken together, the above data suggested that the enzyme degraded CL-20 via three different routes: Route A, via two single electron transfers necessary to release two nitro-groups from CL-20 to produce two double-denitrated isomers; Route B, via a hydride transfer necessary to produce a denitrohydrogenated product; and Route C, via transfer of two redox equivalents to CL-20 necessary to produce a mono-nitroso derivative of CL-20. This is the first biochemical study which showed that CL-20 degradation can be initiated via more than one pathway.     

Ethanol and amylase production by a newly isolated Clostridium sp.

A newly isolated, anaerobic, mesophillic bacterium, Clostridium sp. strain YK-3, ferments pentoses, hexoses, oligosaccharides and polysaccharides, such as soluble starch and glycogen, to ethanol and acetate. The potential of this strain for ethanol and amylase production has been examined. Ethanol was the major product and acetate a minor one. The organism could grow with soluble starch in the presence of 40 g ethanol/l. Extracellular -amylase activity was detected when the strain was cultivated with soluble starch, glycogen or dextrin. The optimum pH of this amylase was 5.5 to 7.5 with an optimum temperature of 50°C.The authors are with the Laboratory of Applied Microbiology, Faculty of Agriculture, Yamagata University, Tsuruoka 997, Japan.     

Purification and characterisation of extracellular protease produced by Clostridium sp. from Schirmacher oasis,Antarctica

One anaerobic, proteolytic bacterium isolated from Schirmacher oasis, Antarctica was characterised taxonomically. Based on morphology, biochemical characteristics and 16S rRNA sequence the isolate was identified as Clostridium species with closest similarity with Clostridium subterminale. Isolate was psychrotrophic forming maximum cell mass between 5 and 10 °C and produced extracellular protease. Growth was observed in the pH range of 6.5–8.5 with optimum at pH 8. Protease was purified 12.7-fold with a total yield of 26.2%. Effect of temperature, pH and salt concentration on enzyme activity were studied. Protease was found to be a serine-type metaloenzyme, which is active in a broad range of pH. It was moderately thermolabile and resistant to SDS. Enzyme kinetics revealed a tendency to decrease K_m with increase in temperature for casein substrate.     

废弃活性污泥中产聚羟基脂肪酸酯菌株Bacillus sp. PB-3的发酵条件优化

通过尼罗红染色法结合荧光显微镜镜检,从废弃活性污泥中分离得到1株高产聚羟基脂肪酸酯(PHAs)的菌株Bacillus sp.PB-3,经气相色谱法鉴定该菌株胞内产物为聚β-羟基丁酸酯(PHB)。对培养基成分及发酵条件优化后,获得最佳培养方案:12 g/L的葡萄糖为C源,2 g/L的牛肉膏为N源,初始pH 7.5,培养基装液量80 mL,转速为200 r/min,37℃培养48 h,PHB质量分数可达菌体干质量的32.09%,比优化前提高30%。     

Physicochemical and spectroscopic characteristics of dissolved organic matter extracted from municipal solid waste (MSW) and their influence on the landfill biological stability

For the purpose of evaluating the stability of municipal solid waste (MSW) excavated from a landfill, dissolved organic matter was extracted and characterized by physicochemical and spectroscopic methods. Results showed that dissolved organic carbon concentration, ratio of dissolved organic carbon to dissolved organic nitrogen, and specific ultraviolet absorbance at 254 nm were in the range of 0.383-3.502 g kg⁻¹, 0.388-3.693 and 2.700-4.629 L mg⁻¹ m⁻¹, respectively, indicating the stability of MSW. Results obtained from Fourier transform infrared spectra have demonstrated that the stability of excavated MSW was characterized by disappearance of some easily biodegradable compounds; and the 1635/1406 ratio varied from 0.979 to 1.840 and was higher than that of the matured compost. The excitation-emission matrix spectra have shown that the principal components in excavated MSW comprised humic substances and the MSW was stable by the presence of a peak with wavelength pair of ∼280/420 nm.     

Production of hexanoic acid from d-galactitol by a newly isolated Clostridium sp. BS-1

In a study screening anaerobic microbes utilizing d-galactitol as a fermentable carbon source, four bacterial strains were isolated from an enrichment culture producing H₂, ethanol, butanol, acetic acid, butyric acid, and hexanoic acid. Among these isolates, strain BS-1 produced hexanoic acid as a major metabolic product of anaerobic fermentation with d-galactitol. Strain BS-1 belonged to the genus Clostridium based on phylogenetic analysis using 16S rRNA gene sequences, and the most closely related strain was Clostridium sporosphaeroides DSM 1294^T, with 94.4% 16S rRNA gene similarity. In batch cultures, Clostridium sp. BS-1 produced 550 ± 31 mL L⁻¹ of H₂, 0.36 ± 0.01 g L⁻¹ of acetic acid, 0.44 ± 0.01 g L⁻¹ of butyric acid, and 0.98 ± 0.03 g L⁻¹ of hexanoic acid in a 4-day cultivation. The production of hexanoic acid increased to 1.22 and 1.73 g L⁻¹ with the addition of 1.5 g L⁻¹ of sodium acetate and 100 mM 2-(N-morpholino)ethanesulfonic acid (MES), respectively. Especially when 1.5 g L⁻¹ of sodium acetate and 100 mM MES were added simultaneously, the production of hexanoic acid increased up to 2.99 g L⁻¹. Without adding sodium acetate, 2.75 g L⁻¹ of hexanoic acid production from d-galactitol was achieved using a coculture of Clostridium sp. BS-1 and one of the isolates, Clostridium sp. BS-7, in the presence of 100 mM MES. In addition, volatile fatty acid (VFA) production by Clostridium sp. BS-1 from d-galactitol and d-glucose was enhanced when a more reduced culture redox potential (CRP) was applied via addition of Na₂S·9H₂O.     

Improvement of ethanol production of themophilic Clostridium sp. by Mutation

Three thermophilic Clostridium strains were isolated from soil as cellulose-fermenting bacteria wich produced ethanol, lactic acid, and acetic acid from cellulose at 60°C. To increase ethanol productivity, strains no. 187 was mutated with N-methyl-N′-nitro-N-nitrosguanidine. The resultant mutant, no 187-102-27, was superior to the original strain in ethanol production, and produced less lactic and acetic acid. The activities of some enzymes involved in the biosynthesis of the lactic and acetic acid of mutant no. 187-102-27 were lower than those of the original strain. These results are highly consistent with the acid production of the mutant strain being low.     

Taxonomic studies on a psychrophilic Clostridium from vacuum-packed beef: Description of Clostridium estertheticum sp. nov.

Abstract Taxonomic studies were performed on an anaerobic Gram-positive, spore-forming, psychrophilic bacterium originally isolated from spoiled vacuum-packed refrigerated beef. Based on the present finding it is proposed that this unknown psychrophilic bacterium be classified as a new species of the genus Clostridium , as Clostridium estertheticum sp. nov. The type strain is NCIMB 12511.     

Lysinibacillus jejuensis sp. nov., isolated from swinery waste

A Gram-positive, endospore-forming, rod-shaped bacterium, designated strain N2-5^T, was isolated from swinery waste collected in Jeju, Republic of Korea. A phylogenetic analysis based on 16S rRNA gene sequences demonstrated that strain N2-5^T formed a phyletic group within the phylum Firmicutes with less than 97.0% similarities to members of the genus Lysinibacillus, its nearest phylogenetic neighbors. The highest levels of sequence similarity to the isolate were observed against Lysinibacillus xylanilyticus XDB9^T (96.8%), Lysinibacillus macroides LMG 18474^T (95.6%), and Lysinibacillus parviboronicapiens BAM-582^T (95.6%). The organism grew optimally at 30°C and pH 7 and in the presence of 1–3% (w/v) NaCl. Strain N2-5^T was chemotaxonomically characterized by possessing menaquinone-7 (MK-7) as the major menaquinone, and iso-C_15:0 (54.9%), iso-C_17:1 ω10c (12.0%), and C_16:1 ω7c alcohol (11.8%) as the predominant fatty acids. The genomic DNA G+C content of the novel strain was 43.3 mol% and the cell-wall peptidoglycan was type A4α. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. Based on its phenotypic properties and phylogenetic data, strain N2-5^T (=DSM 28310^T =KCTC13837^T) represents a novel species in the genus Lysinibacillus, for which the name Lysinibacillus jejuensis sp. nov. is proposed.     

Coliforms in aerosols generated by a municipal solid waste recovery system.

Airborne total and fecal coliform concentrations averaged 2.1 X 10(3) and 9.9 X 10(2)/m3, respectively, inside an operating solid waste recovery system. Installation of dust control equipment reduced these levels by 50%. Frequency of recovery of coliforms also dropped by 15%.     

Repeated removal of cadmium and zinc from an industrial effluent by waste biomass Sargassum sp.

Waste biomass Sargassum sp. biosorbed 100% of Cd²⁺ and 99.4% of Zn²⁺ from a 3 and 98 mg l^–1 solution (pH 4.5), respectively, at the end of four serial experiments. Of the five desorbents studied in consecutive adsorption/desorption cycles, CaCl₂ 0.05 M eluted nearly 40% of both metals and decreased the biosorption in only 8% and 17% of Cd²⁺ and Zn²⁺, respectively. Although NaOH desorbent improved the heavy metal uptake from the second cycle onwards, it did not elute metals from the pre-loaded biomass.     

Environmental assessment of energy production from municipal solid waste incineration

Background, Aims and Scope During the combustion of municipal solid waste (MSW), energy is produced which can be utilized to generate electricity. However, electricity production from incineration has to be evaluated from the point view of the environmental performance. In this study, environmental impacts of electricity production from waste incineration plant in Thailand are compared with those from Thai conventional power plants. Methods The evaluation is based on a life cycle perspective using life cycle assessment (LCA) as the evaluation tool. Since MSW incineration provides two services, viz., waste management and electricity production, the conventional power production system is expanded to include landfilling without energy recovery, which is the most commonly used waste management system in Thailand, to provide the equivalent function of waste management. Results The study shows that the incineration performs better than conventional power plants vis-à-vis global warming and photochemical ozone formation, but not for acidification and nutrient enrichment. Discussion There are some aspects which may influence this result. If landfilling with gas collection and flaring systems is included in the analysis along with conventional power production instead of landfilling without energy recovery, the expanded system could become more favorable than the incineration in the global warming point of view. In addition, if the installation of deNO_x process is employed in the MSW incineration process, nitrogen dioxide can be reduced with a consequent reduction of acidification and nutrient enrichment potentials. However, the conventional power plants still have lower acidification and nutrient enrichment potentials. Conclusions The study shows that incineration could not play the major role for electricity production, but in addition to being a waste management option, could be considered as a complement to conventional power production. To promote incineration as a benign waste management option, appropriate deNO_x and dioxin removal processes should be provided. Separation of high moisture content waste fractions from the waste to be incinerated and improvement of the operation efficiency of the incineration plant must be considered to improve the environmental performance of MSW incineration. Recommendations This study provides an overall picture and impacts, and hence, can support a decision-making process for implementation of MSW incineration. The results obtained in this study could provide valuable information to implement incineration. But it should be noted that the results show the characteristics only from some viewpoints. Outlook Further analysis is required to evaluate the electricity production of the incineration plant from other environmental aspects such as toxicity and land-use.