Genetic transfer of clumping phenotype inAnacystis nidulans

Occasionally a mutation occurs in liquid cultures ofAnacystis nidulans, spreading quickly through the population and causing cells to adhere together in clumps. This phenotype is stable indefinitely and is an inherited characteristic of all cells within a clumping culture. Inoculation with a few living cells from a clumping culture quickly produces the clumping genotype in a majority of cells within a previously non-clumping culture. Killed cells, broken cell extracts, or media from clumping cultures do not produce aggregation in non-clumping cultures. Actively growing cells in clumping cultures do not affect non-clumping cultures when separated by 0.4 μm Millipore filter. Apparently transfer of the clumping trait requires direct contact between living cells. Pili-like projections connect individual cells within clumps, but no slime layer or capsule is seen. Clumps can be dispersed without cell damage; reaggregation requires photosynthesis.     

Capsule-transmitted gut symbiotic bacterium of the Japanese common plataspid stinkbug, Megacopta punctatissima.

The Japanese common plataspid stinkbug, Megacopta punctatissima, deposits small brown particles, or symbiont capsules, on the underside of the egg mass for the purpose of transmission of symbiotic bacteria to the offspring. We investigated the microbiological aspects of the bacteria contained in the capsule, such as microbial diversity, phylogenetic placement, localization in vivo, and fitness effects on the host insect. Restriction fragment length polymorphism analysis of 16S ribosomal DNA clones revealed that a single bacterial species dominates the microbiota in the capsule. The bacterium was not detected in the eggs but in the capsules, which unequivocally demonstrated that the bacterium is transmitted to the offspring of the insect orally rather than transovarially, through probing of the capsule content. Molecular phylogenetic analysis showed that the bacterium belongs to the gamma-subdivision of the Proteobacteria. In adult insects the bacterium was localized in the posterior section of the midgut. Deprivation of the bacterium from the nymphs resulted in retarded development, arrested growth, abnormal body coloration, and other symptoms, suggesting that the bacterium is essential for normal development and growth of the host insect.     

Capsule-Transmitted Gut Symbiotic Bacterium of the Japanese Common Plataspid Stinkbug, Megacopta punctatissima

The Japanese common plataspid stinkbug, Megacopta punctatissima, deposits small brown particles, or symbiont capsules, on the underside of the egg mass for the purpose of transmission of symbiotic bacteria to the offspring. We investigated the microbiological aspects of the bacteria contained in the capsule, such as microbial diversity, phylogenetic placement, localization in vivo, and fitness effects on the host insect. Restriction fragment length polymorphism analysis of 16S ribosomal DNA clones revealed that a single bacterial species dominates the microbiota in the capsule. The bacterium was not detected in the eggs but in the capsules, which unequivocally demonstrated that the bacterium is transmitted to the offspring of the insect orally rather than transovarially, through probing of the capsule content. Molecular phylogenetic analysis showed that the bacterium belongs to the γ-subdivision of the Proteobacteria. In adult insects the bacterium was localized in the posterior section of the midgut. Deprivation of the bacterium from the nymphs resulted in retarded development, arrested growth, abnormal body coloration, and other symptoms, suggesting that the bacterium is essential for normal development and growth of the host insect.     

Novel aspects of symbiotic (polyvinyl alcohol) biodegradation

A new polyvinyl alcohol (PVA)-degrading bacterium was isolated from activated sludge sampled during a waste water treatment process and identified as Sphingomonas sp. Its PVA oxidase activity and alcohol dehydrogenase activity for various low-molecular-weight secondary alcohols were detected. Both activities were associated with cells of the degrader, and they were not extracellular. Under optimal conditions, the isolate was able to degrade 500 mg of PVA per litre in 2 weeks. The strain required pyrroloquinoline quinone (PQQ) and another growth factor, the later could be supplied by a co-isolated Rhodococcus erythropolis strain. The findings stressed the complex nature of environmental PVA degradation and proved that other factors different from PQQ could be important in symbiotic biodegradation of PVA with some sphingomonads.     

Outermost-cell-surface changes in an encapsulated strain of Staphylococcus aureus after preservation by freeze-drying

The effects of drying time during freeze-drying on the outermost cell surface of an encapsulated strain of Staphylococcus aureus S-7 (Smith, diffuse) were investigated, with special attention paid to capsule and slime production. To quantify capsule and slime production, capsule antigen production and cellular characteristics such as growth type in serum-soft agar, cell volume index, and clumping factor reaction were examined. After freeze-drying the colonial morphology of strain S-7 was altered from a diffuse to a compact type in serum-soft agar. In accordance with these changes, the titer of the clumping factor reaction increased while the cell volume index, capsule and slime production, and capsule antigen production were markedly decreased in parallel with the period of freeze-drying. The ability of the strain to adhere to collagen, fibrinogen, and soybean lectin was also compared before and after freeze-drying. Fibrinogen levels slightly increased when 10% skim milk and 2% honey were used as cryoprotective agents and showed a remarkable increase when 0.05 M phosphate buffer was used as a control. Also, the ability of strain S-7 to adhere to soybean lectin declined, whereas no changes were observed for collagen under any conditions. Strain S-7 was phage nontypable before freeze-drying but the number of typable cells increased after freeze-drying; phage-typable cells reacted to phage 52 alone after 5 h of freeze-drying, but additional cells also proved to be phage typable to phage 42E after 10 h. Electron micrographs indicated that strain S-7, an encapsulated strain, was converted to an unencapsulated state after freeze-drying.(ABSTRACT TRUNCATED AT 250 WORDS)     

Outermost-cell-surface changes in an encapsulated strain of Staphylococcus aureus after preservation by freeze-drying.

The effects of drying time during freeze-drying on the outermost cell surface of an encapsulated strain of Staphylococcus aureus S-7 (Smith, diffuse) were investigated, with special attention paid to capsule and slime production. To quantify capsule and slime production, capsule antigen production and cellular characteristics such as growth type in serum-soft agar, cell volume index, and clumping factor reaction were examined. After freeze-drying the colonial morphology of strain S-7 was altered from a diffuse to a compact type in serum-soft agar. In accordance with these changes, the titer of the clumping factor reaction increased while the cell volume index, capsule and slime production, and capsule antigen production were markedly decreased in parallel with the period of freeze-drying. The ability of the strain to adhere to collagen, fibrinogen, and soybean lectin was also compared before and after freeze-drying. Fibrinogen levels slightly increased when 10% skim milk and 2% honey were used as cryoprotective agents and showed a remarkable increase when 0.05 M phosphate buffer was used as a control. Also, the ability of strain S-7 to adhere to soybean lectin declined, whereas no changes were observed for collagen under any conditions. Strain S-7 was phage nontypable before freeze-drying but the number of typable cells increased after freeze-drying; phage-typable cells reacted to phage 52 alone after 5 h of freeze-drying, but additional cells also proved to be phage typable to phage 42E after 10 h. Electron micrographs indicated that strain S-7, an encapsulated strain, was converted to an unencapsulated state after freeze-drying.(ABSTRACT TRUNCATED AT 250 WORDS)     

Metabolic Adaptations of Azospirillum brasilense to Oxygen Stress by Cell-to-Cell Clumping and Flocculation

The ability of bacteria to monitor their metabolism and adjust their behavior accordingly is critical to maintain competitiveness in the environment. The motile microaerophilic bacterium Azospirillum brasilense navigates oxygen gradients by aerotaxis in order to locate low oxygen concentrations that can support metabolism. When cells are exposed to elevated levels of oxygen in their surroundings, motile A. brasilense cells implement an alternative response to aerotaxis and form transient clumps by cell-to-cell interactions. Clumping was suggested to represent a behavior protecting motile cells from transiently elevated levels of aeration. Using the proteomics of wild-type and mutant strains affected in the extent of their clumping abilities, we show that cell-to-cell clumping represents a metabolic scavenging strategy that likely prepares the cells for further metabolic stresses. Analysis of mutants affected in carbon or nitrogen metabolism confirmed this assumption. The metabolic changes experienced as clumping progresses prime cells for flocculation, a morphological and metabolic shift of cells triggered under elevated-aeration conditions and nitrogen limitation. The analysis of various mutants during clumping and flocculation characterized an ordered set of changes in cell envelope properties accompanying the metabolic changes. These data also identify clumping and early flocculation to be behaviors compatible with the expression of nitrogen fixation genes, despite the elevated-aeration conditions. Cell-to-cell clumping may thus license diazotrophy to microaerophilic A. brasilense cells under elevated oxygen conditions and prime them for long-term survival via flocculation if metabolic stress persists.     

Possible virulence factors of Staphylococcus sciuri

Staphylococcus sciuri is an opportunistic pathogen of controversial clinical significance. The factors that contribute to colonization and/or infection caused by this bacterium have not been studied intensively so far. The present research was carried out in order to study the presence of potential virulence factors in 121 human and animal isolates of this bacterium. Isolates were examined for biofilm formation, hemagglutination, presence of clumping factor, production of spreading factors and exotoxins, cytotoxicity and capacity to stimulate nitric oxide production. The results showed that S. sciuri is highly capable of biofilm production, that it displays strong proteolytic and DNase activities, produces hemolysins and stimulates nitric oxide production by rat macrophages. Although the present study showed existence of a wide spectrum of possible virulence determinants of S. sciuri, their exact contribution to virulence of this bacterium in vivo remains to be determined.     

木质素降解菌shu-0801降解玉米废弃物的研究

目的:研究分离到的木质素降解菌降解玉米废弃物效果.方法:利用苯胺蓝法从土壤中分离到木质素降解菌shu-0801.结果:研究表明shu-0801木质素降解菌能够显著提高纤维素的转化,提高纤维素酶的降解效率,还原糖的生成量明显提高,shu-0801菌与玉米秸秆粉共培养,可降解玉米废弃物干重约20%.结论:分离到木质素菌降解木质素效率较高,属巨大芽孢杆菌属.     

Enzyme immobilized reactor design for ammonia removal from waste water

Removal of nitrogen compound from waste, water is essential and often accomplished by biological process. To prevent washout and to develop an efficient bioreactor, immobilization of suitable microorganisms could be sensible approach. Strains and permeabilized cells encapsulated in cellulose nitrate microcapsules and immobilized on polystyrene, films were prepared by the method described in the previous study. In the wastewater, treatment system, nitrification of ammonia component is generally known as rate controlling step. To enhance the rate of nitrification, firstly nitrifying strainsNitrosomonas europaea (IFO 14298), are permeabilized chemically, and immobilized on polystyrene, films and secondly oxidation rates of strain system and permeabilized strain system are compared in the same condition. With 30 minute permeabilized cells, it took about 25 hours to oxidize 70% of ammonia in the solution, while it took about 40 hours to treat same amount of ammonia with untreated cells. All the immobilization procedures did not harm to the enzyme activity and no mass transfer resistance through the capsule wall was shown. In the durability test of immobilized system, the system showed considerable activity for the repeated operation for 90 days. With these results, the system developed in this study showed the possibility to be used in the actual waste water treatment system.     

Ester Synthesis by Zoogloea ramigera 115 Grown in the Presence of Ethanol

The ester ethyl butyrate is produced by Zoogloea ramigera 115, a bacterium isolated from an aerobic waste treatment plant, when ethanol is present in culture media. The cells appear to produce butyric acid which is then esterified with residual ethanol in the culture medium.     

Carbohydrates Oxidation by Pseudomonas albosesamae nov. sp.

Taxonomic behaviors of a newly isolated bacterium which produces 2,5-diketogluconic acid in high yield were examined in this paper. The bacterium was isolated from sesame seed. It is aerobic, rod-shaped bacilli (0.6~0.8 × 1.0~3.0 microns) with rounded ends. It occurs singly or as a small mass and shows motility with a polar flagellum. Gram staining and acid-fast staining are both negative. Endospore and capsule are not observed. It does not possess photosynthetic and usual pigments the cell. Glucose and other sugars are attacked with acid production, but no gas formation. Polysaccharides and sucrose are not attacked. This bacterium does not produce acetic acid from ethanol. The above behaviors and other physiological properties which are described in the text lead to the conclusion that the bacterium is a new species situated in the genus Pseudomonas. So, it was named Pseudomonas albosesamae, nov. sp. (Wakisaka) in relation with its isolated origin.     

Proteolytic enzyme and polymer production by Lysobacter gummosus

Summary Lysobacter gummosus grows on whey, utilizing lactose and producing proteolytic enzyme activity with optimum at pH 8 and 50°C. A preliminary characterisation of the polymer produced by L. gummosus detected uronic and neutral sugar residues. Plasmid DNA was not present. This bacterium may have a role in biotechnology for the production of enzyme and biopolymer from whey or in the disposal of dairy effluent in waste treatment systems.     

The spatial distribution of zooplankton populations in the presence and absence of fish

The spatial distribution patterns of the main zooplankton groups in two small experimental ponds, one which contained fish and one which did not, were measured over a twelve month period from March 1983. Populations of all zooplankton groups were generally distributed non-randomly and with varying degrees of aggregation. The aggregation ofDaphnia longispina populations was inversely related to ambient wind speed, indicating a breakdown of behavioural clumping by wind-induced water currents. Evidence that populations ofDaphnia aggregate in response to fish predation was inconclusive. In contrast cyclopoid nauplii showed no evidence of behavioural clumping and the degree of aggregation was not related to wind speed. Nauplii aggregations were however greater in the absence than in the presence of fish.     

Control of Microthrix parvicella growth in activated sludge

Abstract Effects of aerobic and anaerobic conditions on the growth of Microthrix parvicella in the activated sludge were studied to prevent bulking caused by this filamentous bacterium. The study was conducted on a pilot plant with selector and the data were compared with those observed in a full scale plant subjected to severe bulking due to a massive growth of M. parvicella . Both plants were fed with the same settled waste water. A substantial suppression of the growth of M. parvicella was observed in only the experiments where returned activated sludge was mixed with waste water under aerobic conditions. Both the number of filaments and the sludge volume index (SVI) were lower in the pilot plant than in the full scale plant. Under anerobic conditions, the selector was not able to improve the settleability and avoid the growth of M. parvicella .     

Searching <Emphasis Type="Italic">Simkania negevensis</Emphasis> in environmental waters

Simkania negevensis is an obligate intracellular bacterium grouped into the order Chlamydiales. This new amoeba-resistant bacterium represents a novel aetiologic agent of bronchiolitis and community-acquired pneumonia in both adults and children. It has been suggested that Simkania could be an ubiquitous microorganism presented in water environments. In the natural history of infections with amoeba-related bacteria encountered in aquatic habitats, the transmissions by environmental aerosols or contaminated water/air systems have been extensively recognized. Therefore, understanding the feasibility of Simkania infection by these or similar routes is relevant. In the present work, we investigated the prevalence of this novel disease-associated microorganism in water samples from different sources by real-time PCR (qPCR). Our results show Simkania detection in 5 of 185 water analyzed samples (2.7%: 2 of 88 cooling towers and 3 of 8 waste water samples). However, no Simkania was detected in a drinking water.     

Aggregation and release reaction of washed platelets stimulated by lanthanum.

Ionized lanthanum caused clumping of washed platelets. This clumping response could be reversed by chelating agents but was not impaired by known inhibitors of platelets aggregation. Aggregation by lanthanum was not restricted to the unique clumping properties of platelets but occurred in fixed platelets and red cells and was most likely based on an electrostatic interaction.Lanthanum was able to stimulate as well as to inhibit serotonin release from platelets.At a concentration of 1 mM, lanthanum evoked a release of serotonin from washed platelets at 37°C. This release reaction was inhibited at 18°C or by prior treatment of platelets with neuraminidase or NEM.At a high concentration (10 mM), lanthanum did not stimulate the platelet release reaction but inhibited that induced by all stimuli investigated, presumably due to a fixation of membrane molecules.The release reaction promoted by thrombin or A 23187, but not that by collagen, was inhibited by a low concentration of lanthanum (0.1 mM). This inhibition is based on an interaction of lanthanum with the stimuli rather than with the platelet surface.     

Relation between substrate feeding pattern and development of filamentous bacteria in activated sludge processes: Part III. applications with industrial waste waters

Summary Laboratory scale activated sludge systems were operated under regimes of continuous or intermittent feeding of the waste water. Industrial waste waters from breweries, a dairy plant and a petro-chemical plant were investigated. The systems were started up with sludge from a municipal waste water plant or more often with sludges obtained from the corresponding industrial waste water treatment plants. It was found that intermittently fed systems produced sludges with better settleability characteristics than systems that were continuously supplemented with waste water. Our previous hypothesis that in intermittent systems floc forming bacteria become dominant as a result of higher substrate uptake rates was confirmed and may thus be extended to waste waters containing readily available substrates such as carbohydrates (brewery-and dairy waste water) or acids (petro-chemical waste water). Supplementation of brewery waste water with urea had a negative influence on sludge settleability, especially in continuously operated systems.     

Morphological and molecular characteristics of a new species of Pasteuria parasitic on Meloidogyne ardenensis

A species of the hyper-parasitic bacterium Pasteuria was isolated from the root-knot nematode Meloidogyne ardenensis infecting the roots of ash (Fraxinus excelsior). It is morphologically different from some other Pasteuria pathogens of nematodes in that the spores lack a basal ring on the ventral side of the spore and have a unique clumping nature. Transmission electron microscopy (TEM) showed that the clumps of spores are not random aggregates but result from the disintegration of the suicide cells of the thalli. Sporulation within each vegetative mycelium was shown to be asynchronous. In addition to the novel morphological features 16S rRNA sequence analysis showed this to be a new species of Pasteuria which we have called P. hartismeri. Spores of P. hartismeri attach to juveniles of root-knot nematodes infecting a wide range of plants such as mint (Meloidogyne hapla), rye grass (unidentified Meloidogyne sp.) and potato (Meloidogyne fallax).     

Demographic and macro-morphological evidence for common reed dieback in central Italy

Background: Phragmites australis dieback syndrome, recently reported for the Mediterranean basin, features several symptomatic traits among which the clumping habit seems to be one of the most diagnostic.

Aims: We evaluated the effect of water depth on the intensity of the clumping habit and evaluated the diagnostic role of other traits.

Methods: We investigated patterns of macro-morphological (culm height and diameter, flowering head and dead apical bud rates) and demographic (density) traits of P. australis in function of submersion (PF-permanent vs. NF-temporary) at five Italian wetland sites. We related the occurrence of clumping and its frequency with water depth.

Results: There were clear trends, modulated by site-specific effects, for most of the considered traits in function of the duration of submersion. The clumping rate was close to zero in NF-stands, reached high values in PF-stands and was positively correlated with water depth.

Conclusions: We have shown that permanent submersion with deep water levels plays a crucial role in the occurrence of reed dieback. As all other considered traits, with the exception of the occurrence of dead apical buds, well correlate with the clumping habit, we propose using clumping as a key indicator for detecting potential reed dieback.