Effect of Streptococcus parvulus and Peptostreptococcus magnus on cytotoxin levels of Clostridium difficile in anaerobic continuous flow culture

An anaerobic continuous flow (CF) culture method was used in order to study the effect of Peptostreptococcus magnus and Streptococcus parvulus, anaerobic gram-positive cocci which are members of intestinal bacterial flora, on growth and cytotoxin-activity of Clostridium difficile. The growth- and the cytotoxin activity-patterns of C. difficile in an established CF culture of P. magnus were similar to those of C. difficile alone. On the other hand, in the mixed culture system of C. difficile and S. parvulus, the cytotoxin levels were significantly lower as compared with C. difficile alone in spite of the fact that no differences existed between growth of C. difficile in mixed and single culture systems. The culture filtrate of P. magnus did not influence the growth and cytotoxin production of C. difficile, nor did that of S. parvulus have any effect on growth of C. difficile in static culture. The cytotoxin activity of C. difficile was, however, suppressed by the culture filtrate of S. parvulus. Furthermore, when P. magnus or S. parvulus was statically cultured in a medium containing cytotoxic culture filtrate of C. difficile, the toxin in the medium was not inactivated.     

Study on microbe retting of kenaf fiber

Retting is the predominant problem in the application of kenaf fiber in high-grade products. While the traditional retting method is water retting, that is, the harvested bast kenaf is immersed in natural water (rivers or tanks) in which indigenous bacteria colonize noncellulosic materials in an anaerobic process resulting in severe environmental problems and low-grade fiber, therefore it is inevitable to seek for a pollution-free or little-pollution retting method. With the more application of biotechnology in textile industry, the more biology-treatments have been researched recently. So microbe retting was employed in this work. The fungus strain was isolated from the river in which kenaf fiber was retted, then microbe retting was performed with this fungus. Substrate species, the initial pH of the culture medium, cultivation temperature, retting time and inoculum size are involved in the experiments and the evaluation of retting is based on the residual gum content in retted kenaf fiber. As a result, the removal of pectin in microbe retting of kenaf is 91.31% under the optimal retting conditions. In addition, the effective retting fungus is also observed with microscope as one kind of filamentous epiphyte.     

The retting of flax after preservation with sulphur dioxide

Experiments were carried out to compare the retting of moist flax preserved with sulphur dioxide with that of green dried flax, using whole straw samples. When retted in water at either a constant 20°C or 28°C dried flax was fully retted after 15 and 10 days respectively whereas the sulphur dioxide treated flax (20 g sulphur dioxide kg“¹ flax DM) had undergone almost no retting after 20 days at 20dC or 10 days at 28°C. Pre-soaking the treated flax for 24 h in water and changing the acidified water, raised the pH of the retting liquor to a more normal value but did not significantly increase the rate of retting. Addition of the pectinase enzyme preparation ‘Flaxzyme’ to retting liquor at the rate of either 1.5 g kg^-1 or 3.0 g kg^-1 water, and at a constant temperature of 20°C, substantially increased the rate of retting of both sulphur dioxide treated and dried flax. Optimum degree of retting was achieved at 24 h with the treated flax and at 97 h with the dried flax. Pre-rinsing of the sulphur dioxide treated straw only served to reduce the rate of retting. It was concluded that natural water retting of sulphur dioxide treated flax is retarded by the presence of acidic residues of sulphur dioxide, while enzyme retting is enhanced by these. In further smaller scale experiments using bundles of cut flax straw Flaxzyme was added at concentrations ranging from 0–8.0 ml litre ¹ to containers containing flax in water at ratios from 1:10 to 1: 600 flax:water and the producion of galacturonic acid was used as an indicator of retting progress. Retting took place more rapidly at higher flax to water ratios for a given enzyme concentration. This effect was attributed to the lower pH of higher flax to water ratios which created pH conditions closer to the pH optimum for the retting enzymes. When enzyme retting was compared at a range of buffered pH's the optimum was pH 4.0. At a buffered pH of 4.0 and a temperature of 19°C, retting of sulphur dioxide treated moist flax (flax to water ratio of 1:10) was achieved with Flaxzyme concentrations as low as 0.5 ml litre”‘,much lower than the previously reported minimum of 3.0 ml litre’.     

八种苏铁植物叶轴的比较解剖研究

对苏铁科和泽米铁科8种苏铁植物,即台湾苏铁(Cycas taiwaniana)、海南苏铁(C·hainanensis)、元江苏铁(C·parvulus)、单羽苏铁(C·simplicipinna)、滇南苏铁(C·diannanensis)、越南篦齿苏铁(C·elon-gata)、长刺大泽米铁(Macrozamia longispina)、双子铁(Dioon edule)的叶轴横切面结构进行了比较研究,以期为苏铁植物的系统演化和分类进一步提供解剖学依据,并探讨其解剖结构与生态的适应机制。结果表明,较原始的苏铁科和较进化的泽米铁科叶轴的横切面结构无论在表皮、机械组织、基本组织和维管组织,还是在后含物方面都存在着明显的不同;泽米铁科的大泽米铁属与双子铁属差异也较大;苏铁科科内的6个种则相似性稍大,表明它们是亲缘关系较密切的类群,但每个种都有各自的结构特点。越南篦齿苏铁的维管束排列方式和数目的增加方式与泽米铁科两个种的相似,因此推断它处于较进化的地位。研究还发现苏铁科种类的叶轴的近轴面均像叶片那样具有栅栏组织状同化组织存在。苏铁类植物叶轴具有旱生植物的解剖结构特征:角质层较厚、表皮细胞壁厚、机械组织发达、晶体较多、分泌道和维管束数目较多等结构特征。这些对研究苏铁纲各科及种类之间的进化与亲缘关系提供了佐证,同时揭示了苏铁纲这类古老的植物类群其多个属的种类能够经历如此漫长的地质年代而幸存下来,是由于其在长期演化过程中均形成了这些独特的结构特征,因而具备了相对应的生理功能,能够在恶劣的自然环境下,具备耐干旱、贫瘠、高温及耐盐碱等逆境的结果。     

Diverse cuticular hydrocarbons from Australian canebeetles (Coleoptera: Scarabaeidae)

Abstract  Cuticular hydrocarbon components in beetles of six Australian melolonthines whose larvae damage sugarcane, Antitrogus parvulus (Britton), A. consanguineus (Blackburn), Lepidiota negatoria (Blackburn), L. picticollis (Lea), L. noxia (Britton) and Dermolepida alborhirtum (Arrow), are identified and compared. These species demonstrate species-specific cuticular hydrocarbon profiles with a number of unprecedented structures. Major components have been identified as polymethylated hydrocarbons, 3-methyl substituted n -alkanes, 9,10-allenes and the corresponding C9 alkenes. The similarity of these compounds shows some correlation with the phylogeny of the beetles, but two polymethylated C₂₂ hydrocarbons are unique to A. parvulus. One C₂₅ allene is shown to have a potential role in mate recognition in A. consanguineus.     

基于RAPD分析的中国苏铁属部分种类亲缘关系探讨

利用21个筛选出来的RAPD引物,对苏铁属21个种的22份材料进行分析,获得333个RAPD标记,利用NTSYS(V.2.10e)软件,建立了22份供试材料的UPGMA聚类图,进而探讨了苏铁属21个种类间的亲缘关系。RAPD聚类分析结合形态学研究结果表明:多裂苏铁和叉孢苏铁的亲缘关系很近,聚为一类,多裂苏铁应为叉孢苏铁的一个亚种。西林苏铁、隆林苏铁、叉孢苏铁、尖尾苏铁、叉叶苏铁、长柄叉叶苏铁、多羽叉叶苏铁、长球果苏铁、贵州苏铁、四川苏铁、短叶苏铁、石山苏铁、宽叶苏铁、十万大山苏铁、元江苏铁、仙湖苏铁、海南苏铁、台湾苏铁、广东苏铁、滇南苏铁相互间的亲缘关系均较远,支持各自为独立的种。     

Metabolic regulation in Streptomyces parvulus during actinomycin D synthesis, studied with 13C- and 15N-labeled precursors by 13C and 15N nuclear magnetic resonance spectroscopy and by gas chromatography-mass spectrometry.

Recent studies have suggested that the onset of synthesis of actinomycin D in Streptomyces parvulus is due to a release from L-glutamate catabolic repression. In the present investigation we showed that S. parvulus has the capacity to maintain high levels of intracellular glutamate during the synthesis of actinomycin D. The results seem contradictory, since actinomycin D synthesis cannot start before a release from L-glutamate catabolic repression, but a relatively high intracellular pool of glutamate is needed for the synthesis of actinomycin D. Utilizing different labeled precursors, D-[U-13C]fructose and 13C- and 15N-labeled L-glutamate, and nuclear magnetic resonance techniques, we showed that carbon atoms of an intracellular glutamate pool of S. parvulus were not derived biosynthetically from the culture medium glutamate source but rather from D-fructose catabolism. A new intracellular pyrimidine derivative whose nitrogen and carbon skeletons were derived from exogenous L-glutamate was obtained as the main glutamate metabolite. Another new pyrimidine derivative that had a significantly reduced intracellular mobility and that was derived from D-fructose catabolism was identified in the cell extracts of S. parvulus during actinomycin D synthesis. These pyrimidine derivatives may serve as a nitrogen store for actinomycin D synthesis. In the present study, the N-trimethyl group of a choline derivative was observed by 13C nuclear magnetic resonance spectroscopy in growing S. parvulus cells. The choline group, as well as the N-methyl groups of sarcosine, N-methyl-valine, and the methyl groups of an actinomycin D chromophore, arose from D-fructose catabolism. The 13C enrichments found in the peptide moieties of actinomycin D were in accordance with a mechanism of actinomycin D synthesis from L-glutamate and D-fructose.     

Two Newly Recorded Coprophagid Species from Korea (Coleoptera, Scarabaeidae and Aphodiidae)

A species of Scarabaeidae, Panelus parvulus Waterhouse and a species of Aphodiidae, Aphodius fossor (Linné) are newly recorded from Korea. The diagnosis and photographs of them are provided.     

13C nuclear magnetic resonance and gas chromatography-mass spectrometry studies of carbon metabolism in the actinomycin D producer Streptomyces parvulus by use of 13C-labeled precursors.

Fructose and glutamate metabolism was monitored in cell suspensions of streptomyces parvulus by 13C nuclear magnetic resonance. The experiments were performed for cells grown with various 13C sources in a growth medium containing D-[U-13C]fructose, L-[13C]glutamate, or L-[U-13C]aspartate and with nonlabeled precursors to compare intracellular pools in S. parvulus cells at different periods of the cell life cycle. The transport of fructose into the cells was biphasic in nature; during rapid transport, mannitol, fructose, and glucose 6-phosphate were accumulated intracellularly, whereas during the passive diffusion of fructose, the intracellular carbohydrate pool comprised mainly trehalose (1,1'-alpha-alpha-D-glucose). The regulation of fructokinase activity by the intracellular intermediates may play an important role in fructose catabolism in S. parvulus. Transaldolase activity in S. parvulus was determined from the 13C nuclear magnetic resonance labeling pattern of trehalose carbons obtained from cells grown in medium containing either L-[U-13C]aspartate or L-[U-13C]glutamate. Only carbons 4, 5, and 6 of the disaccharide were labeled. Isotopomer analysis of the trehalose carbons led us to conclude that the flux through the reverse glycolytic pathway, condensation of glyceraldehyde 3-phosphate with dihydroxyacetone phosphate, makes at best a minor contribution to the 13C-labeled glucose units observed in trehalose. The pentose pathway and transaldolase activity can explain the labeling pattern of 4,5,6-13C3 of trehalose. Moreover, the transfer of the 13C label of L-[U-13C]aspartate into the different isotopomers of trehalose C4, C5, and C6 by the transaldolase activity allowed us to calculate the relative fluxes from oxaloacetate via gluconeogenesis and through the tricarboxylic acid cycle. The ratio of the two fluxes is approximately 1. However, the main carbon source for trehalose synthesis in S. parvulus is fructose and not glutamate or aspartate. The 13C enrichment and isotopomer population, measured by nuclear magnetic resonance and gas chromatography-mass spectrometry, of the actinomycin D peptide ring enabled us to specify the origins of the five amino acids of actinomycin D. Threonine and proline exhibited isotopomer populations similar to that of the extracellular L-[13C]glutamate, indicating that protein catabolism is the origin of their 13C label, whereas the isotopomer populations of sarcosine and N-methylvaline were similar to those of the new intracellular pool of S. parvulus that originated from D-[U-13C]fructose during the production of actinomycin D.     

Some lignicolous marine fungi from Thailand, including two new species

Sixteen marine fungi are reported from driftwood collected on the beach at Phuket in Thailand. Two new species, Arenariomyces parvulus J. Koch and Corollospora cinnamomea J. Koch are described.     

Occurrence of the caryophyllid cestode Lytocestus parvulus Furtado, 1963 in Clarias batrachus (L.) in a tropical environment, Kedah, Malaysia

Clarias batrachus (L.) and C. macrocephalus Gunther were collected monthly between October 1982 and September 1984 from Pendang, Kedah, Malaysia. The caryophyllid cestode Lytocestus parvulus Furtado, 1963 was found in 37.7% of C. batrachus examined, with a mean intensity of 11.3. Infection of the cestode in C. macrocephalus was minimal, so detailed study was not attempted. In C. batrachus , no seasonal cycles of prevalence, mean intensity or maturation of the cestode were detected. The prevalence and mean intensity of L. parvulus decreased with increasing size of the fish. The first segment of the intestine was the preferred site where larger numbers of the cestodes and the greatest numbers of mature parasites were found. The number and maturation decreased towards the posterior end of the intestine.     

Bacterial Population Structure of the Jute-Retting Environment

Jute is one of the most versatile bast fibers obtained through the process of retting, which is a result of decomposition of stalks by the indigenous microflora. However, bacterial communities associated with the retting of jute are not well characterized. To investigate the presence of microorganisms during the process of jute retting, full-cycle rRNA approach was followed, and two 16S rRNA gene libraries, from jute-retting locations of Krishnanagar and Barrackpore, were constructed. Phylotypes affiliating to seven bacterial divisions were identified in both libraries. The bulk of clones came from Proteobacteria ( approximately 37, 41%) and a comparatively smaller proportion of clones from the divisions-Firmicutes ( approximately 11, 12%), Cytophaga-Flexibacter-Bacteroidetes group (CFB; approximately 9, 7%), Verrucomicrobia ( approximately 6, 5%), Acidobacteria ( approximately 4, 5%), Chlorobiales ( approximately 5, 5%), and Actinobacteria ( approximately 4, 2%) were identified. Percent coverage value and diversity estimations of phylotype richness, Shannon-Weiner index, and evenness confirmed the diverse nature of both the libraries. Evaluation of the retting waters by whole cell rRNA-targeted flourescent in situ hybridization, as detected by domain- and group-specific probes, we observed a considerable dominance of the beta-Proteobacteria (25.9%) along with the CFB group (24.4%). In addition, 32 bacterial species were isolated on culture media from the two retting environments and identified by 16S rDNA analysis, confirming the presence of phyla, Proteobacteria ( approximately 47%), Firmicutes ( approximately 22%), CFB group ( approximately 19%), and Actinobacteria ( approximately 13%) in the retting niche. Thus, our study presents the first quantification of the dominant and diverse bacterial phylotypes in the retting ponds, which will further help in improving the retting efficiency, and hence the fiber quality.     

Changes in microbial populations during anaerobic flax retting

D onaghy , J.A., L evett , P.N. & H aylock , R.W. 1990. Changes in microbial populations during anaerobic flax retting. Journal of Applied Bacteriology 69 , 634–641.
The bacterial flora of industrial and laboratory scale anaerobic flax rets were determined at intervals throughout the rets. Although after an initial lag period total bacterial numbers remained roughly constant there were fluctuations in the bacterial species constituting the total. Pure culture rets and enzyme assays were used to determine which strains had retting potential. Of the strains demonstrated to have retting ability Bacillus licheniformis and B. subtilis were numerically dominant from 10 to 40 h and were succeeded in dominance by Clostridium acetobutylicum and Cl. felsineum .     

Studies on the microbiology of cassava retting for foo-foo production

O kafor N. I jioma B. O yolu , C. 1984. Studies on the microbiology of cassava retting for foo-foo production. Journal of Applied Bacteriology 56 , 1–13.
Five bacteria ( Bacillus, Lactobacillus, Klebsiella, Leuconostoc, and Corynebacterium ) and a yeast ( Candida spp.) were isolated from cassava being fermented for foo-foo production. Retting of cassava was assessed by determining the weight required to crush cylindrical cassava pieces. A weight in excess of 2.5 kg was required to crush an unfermented peeled cassava cylinder 4 mm diameter and 4 cm long whereas a weight as small as 20 g could crush the same piece after retting. The organisms were studied for their ability to cause retting of sterile cassava pieces, alone or in various combinations. Retting did not occur unless either the Bacillus sp. or the Corynebacterium sp. was present. Only these two organisms hydrolysed starch. The lactic acid bacteria lowered the pH of the fermenting medium although they did not bring about retting. The typical aroma of foo-foo was produced, however, only when the lactic acid bacteria were present in the mixture. Only the Corynebacterium sp., was, however, shown to produce pectinolytic enzymes and it is possible that the Bacillus sp. caused retting by disintegrating other cell components. The typical aroma of foo-foo is disliked by some individuals and it seems possible that foo-foo with a bland aroma, which will presumably be more acceptable to this group, can be produced by using organisms causing retting while excluding those forming lactic acid.     

Characterization of bacterial pectinolytic strains involved in the water retting process

Pectinolytic microorganisms involved in the water retting process were characterized. Cultivable mesophilic anaerobic and aerobic bacteria were isolated from unretted and water-retted material. A total of 104 anaerobic and 23 aerobic pectinolytic strains were identified. Polygalacturonase activity was measured in the supernatant of cell cultures; 24 anaerobic and nine aerobic isolates showed an enzymatic activity higher than the reference strains Clostridium felsineum and Bacillus subtilis respectively. We performed the first genotypic characterization of the retting microflora by a 16S amplified ribosomal DNA restriction analysis (ARDRA). Anaerobic isolates were divided into five different groups, and the aerobic isolates were clustered into three groups. 84.6% of the anaerobic and 82.6% of the aerobic isolates consisted of two main haplotypes. Partial 16S rRNA gene sequences were determined for 12 strains, representative of each haplotype. All anaerobic strains were assigned to the Clostridium genus, whereas the aerobic isolates were assigned to either the Bacillus or the Paenibacillus genus. Anaerobic isolates with high polygalacturonase (PG) activity belong to two clearly distinct phylogenetic clusters related to C. acetobutylicum-C. felsineum and C. saccharobutylicum species. Aerobic isolates with high PG activity belong to two clearly distinct phylogenetic clusters related to B. subtilisT and B. pumilusT.     

亚麻微生物脱胶菌种的筛选与鉴定

在研究天然水沤法脱胶的过程中,通过初筛、复筛,从沤麻主生物期的沤麻液中筛选出两株茵落周围产生透明圈较大、脱胶酶活较高的菌株。通过形态观察,并对其多项生理、生化指标进行了分析研究,初步鉴定并命名为枯草芽孢杆菌A1和B1。初步加茵脱胶实验表明：枯草芽孢杆菌A1产生果胶酶、木聚糖酶,而不产生纤维素酶,脱胶周期为72小时;枯草芽孢杆茵B1产生果胶酶、木聚糖酶和纤维素酶,脱胶周期为50小时。     

Comparative sequence analyses of the 16S rRNA genes of Lactobacillus minutus, Lactobacillus rimae and Streptococcus parvulus: Proposal for the creation of a new genus Atopobium

16S rRNA gene sequencing was performed on the species Lactobacillus minutus, Lactobacillus rimae and Streptococcus parvulus in order to clarify their taxonomic position. Based on comparative sequence analyses these organisms represent a hitherto unknown line of descent within the lactic acid group of bacteria for which a new genus, Atopobium gen. nov., is proposed.