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Characterization of the bacterial flora isolated from a pilot-scale lagoon processing swine manure.

The bacterial flora of an experimental plant that processes liquid swine manure by an aerated compartmented (multistage) lagoon system has been studied. The total flora is characterized by a larger number of oligotrophic bacteria than eutrophic ones. Each compartment displays a specific flora, different from the flora in the manure, and consisting of a complex assembly of Gram-negative and Gram-positive ubiquitous species, such as Aeromonas spp. and Pseudomonas spp., and specialized species, such as Sphingobacterium spp. and Corynebacterium spp. The fecal indicator microorganisms have been shown to disappear in the course of the processing. A significant population of nitrifying bacteria has been observed at levels up to 10(4) bacteria.mL-1.

Animal Husbandry↗

Identification of non-pseudomonad bacteria from fruit bodies of wild agaricales fungi that detoxify tolaasin produced by Pseudomonas tolaasii.

Bacterial isolates from wild Agaricales fungi detoxified tolaasin, the inducer of brown blotch disease of cultivated mushrooms produced by Pseudomonas tolaasii. Mycetocola tolaasinivorans and Mycetocola lacteus were associated with fruit bodies of wild Pleurotus ostreatus and wild Lepista nuda, respectively. Tolaasin-detoxifying bacteria belonging to other genera were found in various wild mushrooms. An Acinetobacter sp. was isolated from fruit bodies of Tricholoma matsutake, Bacillus pumilus was isolated from Coprinus disseminatus, and Sphingobacterium multivorum was isolated from Clitocybe clavipes. A Pedobacter sp., which seemed not be identifiable as any known bacterial species, was isolated from a Clitocybe sp. Tolaasin-detoxifying bacteria identified thus far were attached to the surface of mycelia rather than residing within the fungal cells. M. tolaasinivorans, M. lacteus, B. pumilus, the Pedobacter sp., and S. multivorum efficiently detoxified tolaasin and strongly suppressed brown blotch development in cultivated P. ostreatus and Agaricus bisporus in vitro, but the Acinetobacter sp. did so less efficiently. These bacteria may be useful for the elucidation of mechanisms involved in tolaasin-detoxification, and may become biological control agents of mushroom disease.

Agaricales↗

Role of bacteria in mediating the oviposition responses of Aedes albopictus (Diptera: Culicidae).

The responses of Aedes albopictus to sources of oviposition attractants and stimulants were evaluated with a behavioral bioassay in which females attracted to odorants emanating from water were trapped on screens coated with an adhesive. Gravid mosquitoes were attracted to volatiles from larval-rearing water and soil-contaminated cotton towels. Bacteria were isolated from these substrates and from an organic infusion made with oak leaves. Through fatty acid-methyl ester analyses, six bacterial isolates from larval-rearing water, two isolates from soil-contaminated cotton towels, and three isolates from oak leaf infusion were identified to species. The response of gravid mosquitoes to these isolates was also evaluated in behavioral bioassays. Water containing Psychrobacter immobilis (from larval-rearing water), Sphingobacterium multivorum (from soil-contaminated cotton towels), and an undetermined Bacillus species (from oak leaf infusion) elicited significantly higher oviposition than control water without bacteria. Only volatiles collected from larval rearing water elicited significant electroantennogram responses in females.

Aedes↗

Antimicrobial activity of vanillin against spoilage microorganisms in stored fresh-cut mangoes.

The antimicrobial activity of vanillin against four bacteria (Pantoea agglomerans, Aeromonas enteropelogenes, Micrococcus lylae, and Sphingobacterium spiritovorun), four fungi (Alternaria sp., Aspergillus sp., Penicillium sp., and Fusarium sp.), and three unidentified yeasts isolated from spoiling fresh-cut mango slices was verified in laboratory media adjusted to pH 5.0. MICs of vanillin against the fungi (12.5 to 13.3 mM), bacteria (10 to 13.3 mM), and yeasts (5.0 to 6.7 mM) indicated that all the test species were sensitive to the antimicrobial effects of vanillin. Fresh-cut mango slices were dipped for 1 min in solutions containing 40 and 80 mM vanillin before being packaged in rigid trays and stored at 5 and 10 degrees C to verify the effects of vanillin on the development of the spoilage microflora. Microbiological analysis for up to 14 days of storage revealed that treatment with 80 mM vanillin significantly delayed (P < 0.05) the development of total aerobic bacteria and yeast and mold populations. Vanillin may be a practical preservative for processing fresh-cut mango.

Anti-Bacterial Agents↗

Effect of dietary zeaxanthin on tissue distribution of zeaxanthin and lutein in quail.

PURPOSE: The xanthophyll carotenoids (lutein and zeaxanthin) are hypothesized to delay progression of age-related macular degeneration. The quail has a cone-dominant retina that accumulates carotenoids. The purpose of these experiments was to characterize the carotenoid composition of retina, serum, liver, and fat in quail and to determine whether dietary enrichment with zeaxanthin alters zeaxanthin or lutein concentrations in these tissues. METHODS: Quail were fed for 6 months with a commercial turkey diet (T group; n = 8), carotenoid-deficient diet (C- group; n = 8), or a carotenoid-deficient diet supplemented with 35 mg 3R,3'R-zeaxanthin per kilogram of food, (Z+ group; n = 8). Zeaxanthin was derived from Sphingobacterium multivorum (basonym Flavobacterium). Carotenoids in serum, retina, liver, and fat were analyzed by HPLC. RESULTS: As in the primate fovea, the retina accumulated zeaxanthin, lutein, and cryptoxanthin, and preferentially absorbed zeaxanthin (P < 0.005). In contrast, lutein was preferentially absorbed by liver (P < 0.01) and fat (P < 0.0001). In supplemented females, zeaxanthin increased approximately 4-fold in retina, and 74-, 63- and 22-fold in serum, liver, and fat, respectively. In males, zeaxanthin was elevated approximately 3-fold in retina, and 42-, 17-, and 12-fold in serum, liver, and fat, respectively. Birds fed the Z+ diet absorbed a higher fraction of dietary lutein into serum, but lutein was reduced in the retina (P < 0.05). CONCLUSIONS: Xanthophyll profiles in quail mimic those in primates. Dietary supplements of zeaxanthin effectively increased zeaxanthin concentrations in serum, retina, liver, and fat. The robust response to zeaxanthin supplementation identifies the quail as an animal model for exploration of factors regulating delivery of dietary carotenoids to the retina.

Adipose Tissue↗

Bacterial diversity of a soil sample from Schirmacher Oasis, Antarctica.

The bacterial diversity of a soil sample collected in the vicinity of Lake Zub, Schirmacher Oasis, Antarctica, was determined both by establishing pure colonies of culturable bacteria and by cloning the total 16S rDNA of the soil and establishing the phylogeny of the clones. Analysis of the 16S rRNA gene clones indicated that the bacteria belonged to the classes alpha-proteobacteria, beta-proteobacteria, gamma-proteobacteria, Gemmatimonas, Bacteriodetes, Actinobacteria, Chloroflexi and Chlamydiae. In addition, seven clones were categorized as unidentified and unculturable in the classes of beta-Proteobacteria, Actinobacteria, Chloroflexi and Chlamydiae. Further, the culturable bacteria from the same site were identified as belonging to the genera Pseudomonas, Sphingobacterium, Arthrobacter, Micrococcus, Brevondimonas, Rhodococcus and Microbacterium. These results identify for the first time the presence of bacteria belonging to the genera Brevundimonas, Microbacterium, Rhodococcus, Serratia, Enterobacter, Rhodopseudomonas, Sphingomonas, Acidovorax, Burkholderia, Nevskia, Gemmatimonas, Xanthomonas and Flexibacter in Antarctica. Further, comparison of the Antarctic soil bacterial diversity with other cold habitats of Antarctica like from sediments, ice and cyanobacterial mat samples indicated that the bacterial diversity in soil was similar to the diversity observed in the continental shelf sediment sample. The Antarctic soil clones also resembled the bacterial diversity of soils from other geographical regions, but were unique in that none of the clones from the soil belonged to the uncultured Y, O, G, A and B groups common to all soil samples.

Antarctic Regions↗

['In vitro' activity of different antimicrobial agents on Gram-negative nonfermentative bacilli, excluding Pseudomonas aeruginosa and Acinetobacter spp].

Gram-negative nonfermentative bacilli (NFB) are widely spread in the environment. Besides of difficulties for identification, they often have a marked multiresistance to antimicrobial agents, including those active against Pseudomonas aeruginosa. The objective of this study was to evaluate the 'in vitro' activity of different antimicrobial agents on 177 gram-negative nonfermentative bacilli isolates (excluding Pseudomonas aeruginosa and Acinetobacter spp.) isolated from clinical specimens. Minimum inhibitory concentrations (MIC) were determined according to the Mueller Hinton agar dilution method against the following antibacterial agents: ampicillin, piperacillin, piperacillin-tazobactam, sulbactam, cefoperazone, cefoperazone-sulbactam, ceftazidime, cefepime, aztreonam, imipenem, meropenem, colistin, gentamicin, amikacin, trimethoprim-sulfamethoxazole, chloramphenicol, erythromycin, rifampin, norfloxacin, ciprofloxacin and minocycline. Seven isolates: Sphingobacterium multivorum (2), Sphingobacteriumspiritivorum (1), Empedobacterbrevis (1), Weeksella virosa (1), Bergeyella zoohelcum (1) and Oligella urethralis (1), were tested for amoxicillin-clavulanic acid and ampicillin-sulbactam susceptibility, and susceptibility to cefoperazone or sulbactam was not determined. Multiresistance was generally found in Stenotrophomonas maltophilia, Burkholderia cepacia, Chryseobacterium spp., Myroides spp., Achromobacter xylosoxidans, and Ochrobactrum anthropi isolates. On the other hand, Pseudomonas stutzeri, Shewanella putrefaciens-algae, Sphingomonas paucimobilis, and Pseudomonas oryzihabitans, Bergeyella zoohelcum, Weeksella virosa and Oligella urethralis were widely susceptible to the antibacterial agents tested. As a result of the wide variation in antimicrobial susceptibility shown by different species, a test on susceptibility to different antibacterial agents is essential in order to select an adequate therapy. The marked multiresistance evidenced by some species, prompts the need to develop new antimicrobial agents active against this group of bacteria and to search for synergistic combinations.

Anti-Bacterial Agents↗

Discovery of a new type of sialidase, "KDNase," which specifically hydrolyzes deaminoneuraminyl (3-deoxy-D-glycero-D-galacto-2-nonulosonic acid) but not N-acylneuraminyl linkages.

The release of 3-deoxy-D-glycero-D-galacto-2-nonulosonic acid (KDN, deaminoneuraminic acid) residues from their alpha-ketosidic linkage is required to determine the structural and functional role of KDN-glycoconjugates in sources as disparate as trout egg polysialoglycoproteins and human cancers. We report for the first time the isolation and characterization of a novel type of sialidase (KDNase), which specifically hydrolyzes KDN ketosidic but not N-acylneuraminyl linkages. KDNase activity was assayed using 4-methylumbelliferyl KDN (4-MU-KDN). A KDNase-producing microorganism was identified as Sphingobacterium multivorum. The affinity-purified enzyme was designated KDNase SM to denote its origin and that it was free of N-acylneuraminidase, proteolytic, and other glycosidase activities. KDNase SM activity toward 4-MU-KDN was not inhibited by the N-acylneuraminidase inhibitor, 2,3-dehydro-2-deoxy-N-acetylneuraminic acid. KDNase SM released free KDN from naturally occurring substrates, including (KDN)GM3, KDN-glycoprotein, which bears a number of O-linked chains of KDN alpha 2-->3Gal beta 1-->3GalNAc alpha 1-->3 (KDN alpha 2-->(-->8KDN alpha 2-->)n-->6)GalNAc alpha 1-->, and the biantennary complex-type of N-glycan, KDN alpha 2-->3Gal beta 1-->4GlcNAc beta 1-->2Man alpha 1-->6(KDN alpha 2-->3Gal beta 1-->4GlcNAc beta 1-->2Man alpha 1-->3)Man beta 1-->4GlcNAc beta 1-->4GlcNAc. KDNase SM thus exhibited a broad linkage specificity and was able to hydrolyze the KDN residues ketosidically linked alpha 2-->3, alpha 2-->6, and alpha 2-->8. The enzyme did not release Neu5Ac or Neu5Gc from 4-MU-Neu5Ac, N-acetyl-neuraminyllactose, colominic acid, or other Sia(Neu5Ac or Neu5Gc)-containing glycoconjugates.

Bacteria↗

Substrate uptake in extremely halophilic microbial communities revealed by microautoradiography and fluorescence in situ hybridization.

The combination of fluorescence in situ hybridization and microautoradiography (FISH-MAR approach) was applied to brine samples of a solar saltern crystallizer pond from Mallorca (Spain) where the simultaneous occurrence of Salinibacter spp. and the conspicuous square Archaea had been detected. Radioactively labeled bicarbonate, acetate, glycerol, and an amino acid mixture were tested as substrates for the microbial populations inhabiting such brines. The results indicated that hitherto uncultured 'square Archaea' do actively incorporate amino acids and acetate. However, Salinibacter spp. only showed amino acid incorporation in pure culture, but no evidence of such activity in their natural environment could be demonstrated. No glycerol incorporation was observed for any component of the microbial community.

Autoradiography↗

Intraspecific comparative analysis of the species Salinibacter ruber.

Salinibacter ruber is the first extremely halophilic member of the Bacteria domain of proven environmental relevance in hypersaline brines at or approaching NaCl saturation, that has been brought to pure culture. A collection of 17 strains isolated from five different geographical locations (Mallorca, Alicante, Ebro Delta, Canary Islands, and Peruvian Andes) were studied following the currently accepted taxonomic approach. Additionally, random amplification of genomic DNA led to the phenetic analysis of the intraspecific diversity. Altogether the taxonomic study indicated that S. ruber remained highly homogeneous beyond any geographical barrier. However, genomic fingerprints indicated that populations from different isolation sites could still be discriminated.

Bacterial Physiological Phenomena↗

Pedobacter sandarakinus sp. nov., isolated from soil.

A Gram-negative, non-motile, rod-shaped bacterial strain, designated DS-27(T), was isolated from a soil sample, and its taxonomic position was investigated by using a polyphasic approach. The organism grew optimally at 30 degrees C and in the presence of 0-0.5 % (w/v) NaCl. Strain DS-27(T) contained MK-7 as the predominant menaquinone and iso-C(15 : 0), C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH and iso-C(17 : 0) 3-OH as the major fatty acids. The DNA G + C content was 39.7 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain DS-27(T) is most closely related to the genus Pedobacter of the family Sphingobacteriaceae. Similarity values between the 16S rRNA gene sequences of strain DS-27(T) and the type strains of recognized Pedobacter species ranged from 90.6 to 95.5 %. Differential phenotypic properties, together with the phylogenetic distinctiveness, were sufficient to categorize strain DS-27(T) as representing a species that is separate from recognized Pedobacter species. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain DS-27(T) (=KCTC 12559(T) = CIP 108922(T)) was classified in the genus Pedobacter as a member of a novel species, for which the name Pedobacter sandarakinus sp. nov. is proposed.

Culture Media↗

Emendation of the genus Flammeovirga and Flammeovirga aprica with the proposal of Flammeovirga arenaria nom. rev., comb. nov. and Flammeovirga yaeyamensis sp. nov.

The taxonomic positions of five bacterial strains isolated from the Yaeyama Islands of Japan and 'Microscilla arenaria' NBRC 15982 were determined using a polyphasic taxonomic approach. 16S rRNA gene sequence analyses placed all of the strains close to the genus Flammeovirga. DNA-DNA hybridization studies, biochemical and physiological characterizations and chemotaxonomic analyses suggested that 'M. arenaria' NBRC 15982 and the five novel isolates represented two separate species of the genus Flammeovirga. Emendation of the genus Flammeovirga Nakagawa et al. 1997 and the species Flammeovirga aprica (Reichenbach 1989) Nakagawa et al. 1997 is proposed. In addition, 'Microscilla arenaria' Lewin 1969 is proposed as Flammeovirga arenaria nom. rev., comb. nov. (with the type strain NBRC 15982(T)=CIP 109101(T)) and the novel isolates are proposed as Flammeovirga yaeyamensis sp. nov. (type strain IR25-3(T)=NBRC 100898(T)=CIP 109099(T)).

Bacterial Typing Techniques↗

Effects of nutrient availability and Ochromonas sp. predation on size and composition of a simplified aquatic bacterial community.

Predation and competition are two main factors that determine the size and composition of aquatic bacterial populations. Using a simplified bacterial community, composed of three strains characterized by different responses to predation, a short-term laboratory experiment was performed to evaluate adaptations and relative success in communities with experimentally controlled levels of predation and nutrient availability. A strain with a short generation time (Pseudomonas putida), one with high plasticity in cell morphology (Flectobacillus sp. GC5), and one that develops microcolonies (Pseudomonas sp. CM10), were selected. The voracious flagellate Ochromonas sp. was chosen as a predator. To describe adaptations against grazing and starvation, abundance, biomass and relative heterogeneity of bacteria were measured. On the whole, the strains in the predation-free cultures exhibited unicellular growth, and P. putida represented the largest group. The presence of Ochromonas strongly reduced bacterial abundance, but not always the total biomass. The activity of grazers changed the morphological composition of the bacterial communities. Under grazing pressure the relative composition of the community depended on the substrate availability. In the presence of predators, P. putida abundance declined in both high and low nutrient treatments, and Pseudomonas CM10 developed colonies. Flectobacillus was only numerically codominant in the nutrient-rich environments.

Animals↗

Plasmid-encoded gamma-hexachlorocyclohexane degradation genes and insertion sequences in Sphingobium francense (ex-Sphingomonas paucimobilis Sp+).

The lin genes encode the gamma-hexachlorocyclohexane (gamma-HCH or lindane) catabolic pathway in lindane-degrading strains. The location and stability of these genes have been explored in the lindane-degrading Sphingobium francense strain Sp+, and in two non-lindane-degrading mutants (Sp1- and Sp2-). The lin genes, linA, linB, linE and linX were localized by hybridization on three of the six plasmids of the S. francense strain Sp+ showing dispersal within the genome. The linC gene was detected by PCR, but was not detected by hybridization on any of the plasmids. The hybridization of the linA and linX genes was negative with the two non-lindane-degrading mutants S. francense strains, Sp1- and Sp2-. The dynamic of this genome associated with gene loss and acquisition, and plasmid rearrangement was explored by a search for associated insertion sequences. A new insertion sequence, ISSppa4, belonging to the IS21 family was detected and compared with IS6100 and ISsp1. Insertion sequence localization was explored on different hybridization patterns (plasmid, total genome) with the lindane-degrading Sp+ strain and the two non-degrading derivatives (Sp1-, Sp2-). Insertion sequence movement and plasmid rearrangement could explain the emergence of the non-lindane-degrading mutants.

Bacterial Proteins↗

A novel bacterium Saprospira sp. strain PdY3 forms bundles and lyses cyanobacteria.

A helical filamentous cyanobactericidal bacterium was isolated from Dianchi Lake, a eutrophic freshwater lake in Kunming City of the Yunnan Province in China using a special solid medium. This species was designated strain PdY3. This bacterium was identified as a novel Saprospira sp. on the basis of its morphological characteristics and 16S rDNA sequence. Strain PdY3 showed apparent group behavior on the solid medium, forming orderly, bundle-like group structures. These bundles moved as groups. Individuals in a bundle responded to the bundle as a whole. PdY3 also showed group behavior and formed a three-dimensional reticular structure when co-cultured with Anabaena in liquid media. This helical bacterium lysed cyanobacteria through direct contact and its group behavior greatly accelerated the cyanobactericidal process. Our experiments showed that PdY3 caused lysis of 64% of Anabaena cells within 1 day and that its cyanobactericidal range was broad. These results underscore potential application of Saprospira on the control of blooms of cyanobacteria. PdY3 group behavior might allow a more efficient capture of bacterial prey.

Anabaena↗