The Genome of the marine bacterium <Emphasis Type="Italic">Cobetia marina</Emphasis> KMM 296 isolated from the mussel <Emphasis Type="Italic">Crenomytilus grayanus</Emphasis> (Dunker, 1853)

We determined the entire genome sequence of the marine bacterium Cobetia marina KMM 296 de novo, which was isolated from the mussel Crenomytilus grayanus that inhabits the Sea of Japan. The genome that provides the lifestyle of this marine bacterium provides alternative metabolic pathways that are characteristic of the inhabitants of the rhizospheres of terrestrial plants, as well as deep-sea ecological communities (symbiotic and free-living bacteria). The genome of C. marina KMM 296 contains genes that are involved in the metabolism and transport of nitrogen, sulfur, iron, and phosphorus. C. marina strain KMM 296 is a promising source of unique psychrophilic enzymes and essential secondary metabolites.     

Biotechnological potential of a rhizosphere <Emphasis Type="Italic">Pseudomonas</Emphasis><Emphasis Type="Italic">aeruginosa</Emphasis> strain producing phenazine-1-carboxylic acid and phenazine-1-carboxamide

Bacterial phenazine metabolites belong to a group of nitrogen-containing heterocyclic compounds with antimicrobial activities. In this study, a rhizosphere Pseudomonas aeruginosa strain PA1201 was isolated and identified through 16S rDNA sequence analysis and fatty acid profiling. PA1201 inhibited the growth of various pathogenic microorganisms, including Rhizotonia solani, Magnaporthe grisea, Fusarium graminearum, Xanthomonas oryzae pv. oryzae, Xanthomonas oryzae pv. oryzicola, and Staphylococcus aureus. High Performance Liquid Chromatography showed that PA1201 produced high levels of phenazine-1-carboxylic acid (PCA), a registered green fungicide ‘Shenqinmycin’ with the fermentation titers of 81.7 mg/L in pigment producing medium (PPM) and 926.9 mg/L in SCG medium containing soybean meal, corn steep liquor and glucose. In addition, PA1201 produced another antifungal metabolite, phenazine-1-carboxaminde (PCN), a derivative of PCA, with the fermentation titers of 18.1 and 489.5 mg/L in PPM and SCG medium respectively. To the best of our knowledge, PA1201 is a rhizosphere originating P. aeruginosa strain that congenitally produces the highest levels of PCA and PCN among currently reported P. aeruginosa isolates, which endows it great biotechnological potential to be transformed to a biopesticide-producing engineering strain.     

Isolation and algicidal characterization of <Emphasis Type="Italic">Bowmanella denitrificans</Emphasis> S088 against <Emphasis Type="Italic">Chlorella vulgaris</Emphasis>

One strain of algicidal bacterium, named as S088, was isolated from the intestine of healthy sea cucumbers (Stichopus horrens) in the South China Sea. Based on the analysis of its biochemical characteristics and 16S rDNA gene sequence, S088 was identified as Bowmanella denitrificans. Importantly, the algicidal activity of S088 on Chlorella vulgaris was characterized in this study. The initial densities of bacterial and algal cell showed strong influence on the removal rates of chlorophyll a. When the strain S088 was cultured under a complete darkness condition at 30 °C, its algicidal activity reached the highest level. Furthermore, it was found that the filtered supernatant from bacterial cultures had full algicidal activity, suggesting that the secreted compounds from S088 are involved in the observed algicidal action of S088. Moreover, the algicidal compounds were heat tolerant and had no cytotoxicity against fish cells, indicating that S088 would have a promising application as a safe probiotics for S. horrens. Finally, this is the first report about the algicidal activities in B. denitrificans.     

Bioprospecting of <Emphasis Type="Italic">Diaporthe terebinthifolii</Emphasis> LGMF907 for antimicrobial compounds

Antibiotic-resistant bacteria have been observed with increasing frequency over the past decades, driving the search for new drugs and stimulating the interest in natural products sources. Endophytic fungi from medicinal plants represent a great source of novel bioactive compounds useful to pharmaceutical and agronomical purposes. Diaporthe terebinthifolii is an endophytic species isolated from Schinus terebinthifolius, a plant used in popular medicine for several health problems. The strain D. terebinthifolii LGMF907 was previously reported by our group to produce secondary metabolites with biological activity against phytopathogens. Based on these data, strain LGMF907 was chosen for bioprospecting against microorganisms of clinical importance and for characterization of major secondary metabolites. In this study, different culture conditions were evaluated and the biological activity of this strain was expanded. The crude extracts demonstrated high antibacterial activity against Escherichia coli, Micrococcus luteus, Saccharomyces cerevisiae, methicillin-sensitive Staphylococcus aureus, and methicillin-resistant S. aureus. The compounds diaporthin and orthosporin were characterized and also showed activity against the clinical microorganisms evaluated. This study discloses the first isolation of diaporthin and orthosporin from D. terebinthifolii, and revealed the potential of this endophytic fungus to produce secondary metabolites with antimicrobial activity.     

Succinic semialdehyde reductase Gox1801 from <Emphasis Type="Italic">Gluconobacter oxydans</Emphasis> in comparison to other succinic semialdehyde<Emphasis Type="Bold">-</Emphasis>reducing enzymes

Gluconobacter oxydans is an industrially important bacterium that possesses many uncharacterized oxidoreductases, which might be exploited for novel biotechnological applications. In this study, gene gox1801 was homologously overexpressed in G. oxydans and it was found that the relative expression of gox1801 was 13-fold higher than that in the control strain. Gox1801 was predicted to belong to the 3-hydroxyisobutyrate dehydrogenase-type proteins. The purified enzyme had a native molecular mass of 134 kDa and forms a homotetramer. Analysis of the enzymatic activity revealed that Gox1801 is a succinic semialdehyde reductase that used NADH and NADPH as electron donors. Lower activities were observed with glyoxal, methylglyoxal, and phenylglyoxal. The enzyme was compared to the succinic semialdehyde reductase GsSSAR from Geobacter sulfurreducens and the γ-hydroxybutyrate dehydrogenase YihU from Escherichia coli K-12. The comparison revealed that Gox1801 is the first enzyme from an aerobic bacterium reducing succinic semialdehyde with high catalytic efficiency. As a novel succinic semialdehyde reductase, Gox1801 has the potential to be used in the biotechnological production of γ-hydroxybutyrate.     

Co-synthesis of kenyacin 404 and heterologous thurincin H enhances the antibacterial activity of <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis>

Objectives

To develop a recombinant strain of Bacillus thuringiensis that synthesizes two bacteriocins that enhance the antibacterial potency of the strain and that could have applied clinical and industrial value.

Results

We cloned the thurincin H cluster into the pHT3101 vector by assembling two genetic cassettes harboring genes for the synthesis, modification, immunity and transport of thurincin H. This construct was used to transform a thurincin H-sensitive strain of B. thuringiensis that synthesizes the kenyacin 404 to generate the recombinant Btk 404/pThurH which was immune to thurincin H and produces bacteriocins of approximately 3 kDa. A significant increase in the inhibitory activity, respectively, ~?40 and 300%, was observed when compared with parental Btm 269 and Btk 404. Btk 404/pThurH showed increased activity against ten Gram-positive bacteria, including B. cereus, Listeria monocytogenes and B. pseudomycoides, and the Gram-negative bacterium, Sphingobacterium cabi. However, an antagonistic effect against Vibrio parahaemolyticus, relative to native strains, was observed.

Conclusions

We have generated a recombinant strain of B. thuringiensis that co-synthesizes two bacteriocins (kenyacin 404, thurincin H) with improved inhibitory activity, when compared with parental strains. To our knowledge, this is the first study that shows that B. thuringiensis could be manipulated to produce two bacteriocins, one being of heterologous origin, that enhance the antibacterial activity of the recombinant strain.

     

Dual-species biofilm of <Emphasis Type="Italic">Listeria monocytogenes</Emphasis> and <Emphasis Type="Italic">Escherichia coli</Emphasis> on stainless steel surface

Listeria monocytogenes is a Gram-positive bacterium commonly associated with foodborne diseases. Due its ability to survive under adverse environmental conditions and to form biofilm, this bacterium is a major concern for the food industry, since it can compromise sanitation procedures and increase the risk of post-processing contamination. Little is known about the interaction between L. monocytogenes and Gram-negative bacteria on biofilm formation. Thus, in order to evaluate this interaction, Escherichia coli and L. monocytogenes were tested for their ability to form biofilms together or in monoculture. We also aimed to evaluate the ability of L. monocytogenes 1/2a and its isogenic mutant strain (ΔprfA ΔsigB) to form biofilm in the presence of E. coli. We assessed the importance of the virulence regulators, PrfA and σ^B, in this process since they are involved in many aspects of L. monocytogenes pathogenicity. Biofilm formation was assessed using stainless steel AISI 304 #4 slides immersed into brain heart infusion broth, reconstituted powder milk and E. coli preconditioned medium at 25 °C. Our results indicated that a higher amount of biofilm was formed by the wild type strain of L. monocytogenes than by its isogenic mutant, indicating that prfA and sigB are important for biofilm development, especially maturation under our experimental conditions. The presence of E. coli or its metabolites in preconditioned medium did not influence biofilm formation by L. monocytogenes. Our results confirm the possibility of concomitant biofilm formation by L. monocytogenes and E. coli, two bacteria of major significance in the food industry.     

Biosurfactant Production by <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> SNP0614 and its Effect on Biodegradation of Petroleum

An efficient biosurfactant-producing strain was isolated and cultured from Dagang oil field (China) using crude oil as sole source of carbon. Based on partial sequenced 16S rDNA analysis, the isolated strain was identified as Pseudomonas aeruginosa SNP0614. The bacterium P. aeruginosa SNP0614 produced a type of biosurfactant with excessive foam-forming properties. After microbial cultivation at 37°C and 150 rpm for 12 h, the produced biosurfactant was found to reduce the surface tension to 25.4 mN/m with critical micelle concentration (CMC) of 45.0 mg/L. After 20 days of incubation, the biosurfactant exhibited 90% emulsification activity (E₂₄) on crude oil. FTIR spectroscopy of extracted biosurfactant indicated the biosurfactant as lipopeptide. The significant synergistic effect between P. aeruginosa SNP0614 and the mixed oildegrading bacteria resulted in increasing n-alkanes degradation rate by 30%. The strain P. aeruginosa SNP0614 represented as a promising biosurfactant producer and could be applied in a variety of biotechnological and industrial processes, particularly in microbial enhanced oil recovery and the bioremediation of oil pollution.     

Simultaneous Biodegradation of Polyaromatic Hydrocarbons by a <Emphasis Type="Italic">Stenotrophomonas</Emphasis> sp: Characterization of <Emphasis Type="Italic">nid</Emphasis> Genes and Effect of Surfactants on Degradation

A polyaromatic hydrocarbon degrading bacterium was isolated from a petroleum contaminated site and designated as Stenotrophomonas sp. strain IITR87. It was found to utilize pyrene, phenanthrene and benzo(a)pyrene as sole carbon source, but not anthracene, chrysene and fluoranthene. Gas chromatography and mass spectroscopy analysis resulted in identification of pyrene metabolites namely monohydroxypyrene, 4-oxa-pyrene-5-one, dimethoxypyrene and monohydroxyphenanthrene. Southern hybridization using naphthalene dioxygenase gene (nidA) as probe against the DNA of strain IITR87 revealed the presence of nidA gene. PCR analysis suggests dispersed occurrence of nid genes in the genome instead of a cluster as reported in a PAH-degrading Mycobacterium vanbaalenii PYR-1. The nid genes in strain IITR87, dioxygenase large subunit (nidA), naphthalene dioxygenase small subunit (nidB) and aldehyde dehydrogenase gene (nidD) showed more than 97 % identity to the reported nid genes from Mycobacterium vanbaalenii PYR-1. Most significantly, the biodegradation of PAHs was enhanced 25–60 % in the presence of surfactants rhamnolipid and Triton X-100 due to increased solubilization and bioavailability. These results could be useful for the improved biodegradation of high-molecular-weight PAHs in contaminated habitats.     

Cloning of the <Emphasis Type="Italic">cnr</Emphasis> operon into a strain of <Emphasis Type="Italic">Bacillaceae</Emphasis> bacterium for the development of a suitable biosorbent

In this study, a potential microbial biosorbent was engineered to improve its capacity to remediate heavy metal contaminated water resources. A Bacillaceae bacterium isolated from a mining area was transformed with a plasmid carrying the (pECD312)-based cnr operon that encodes nickel and cobalt resistance. The bioadsorption ability of the transformed strain was evaluated for removal of nickel from metallurgical water relative to the wildtype strain. Results showed that transformation improved the adsorption capacity of the bacterium by 37 % at nickel concentrations equivalent to 150 mg/L. Furthermore it was possible to apply prediction modelling to study the bioadsorption behaviour of the transformed strain. As such, this work may be extended to the design of a nickel bioremediation plant utilising the newly developed Bacillaceae bacterium as a biosorbent.     

Molecular characterization of <Emphasis Type="Italic">bmyC</Emphasis> gene of the mosquito pupicidal bacteria, <Emphasis Type="Italic">Bacillus amyloliquefaciens</Emphasis> (VCRC B483) and in silico analysis of bacillomycin D synthetase C protein

A strain of Bacillus amyloliquefaciens (VCRC B483) exhibiting mosquito pupicidal, keratinase and antimicrobial activities was isolated from mangrove forest ecosystem of Andaman and Nicobar Islands. Molecular characterization of the strain showed the presence of lipopeptide encoding bmyC gene. Phylogenetic tree based on protein sequence of this gene exhibited homology with mycosubtilin synthetase of Bacilus atropheus and Iturin synthetase of Bacillus subtilis and B. amyloliquefaciens. This is the first report on the evolutionary conservation of amino acids concerned with the function and structure of bmyC protein of B. amyloliquefaciens. The presence of valine at the 1197th position in our strain was found to be unique and different from the existing strains of B. subtilis and B. amyloliquefaciens. Molecular modelling studies revealed significant changes in the structure of epimerization domain of the bmyC protein with A1197V variation. Crude metabolite of this strain exhibited antifungal activity against Fusarium sp. and Carvularia sp.     

Functional analysis of arabinofuranosidases and a xylanase of <Emphasis Type="Italic">Corynebacterium alkanolyticum</Emphasis> for arabinoxylan utilization in <Emphasis Type="Italic">Corynebacterium glutamicum</Emphasis>

Xylooligosaccharides (XOSs) and arabinoxylooligosaccharides (AXOSs) are major oligosaccharides derived from arabinoxylan. In our previous report, Corynebacterium glutamicum was engineered to utilize XOSs by introducing Corynebacterium alkanolyticum xyloside transporter and β-xylosidase. However, this strain was unable to consume AXOSs due to the absence of α-l-arabinofuranosidase activity. In this study, to confer AXOS utilization ability on C. glutamicum, two putative arabinofuranosidase genes (abf51A and abf51B) were isolated from C. alkanolyticum by the combination of degenerate PCR and genome walking methods. Recombinant Abf51A and Abf51B heterologously expressed in Escherichia coli showed arabinofuranosidase activities toward 4-nitrophenyl-α-l-arabinofuranoside with k _cat values of 150 and 63, respectively, with optimum at pH 6.0 to 6.5. However, Abf51A showed only a slight activity toward AXOSs and was more susceptible to product inhibition by arabinose and xylose than Abf51B. Introduction of abf51B gene into the C. glutamicum XOS-utilizing strain enabled it to utilize AXOSs as well as XOSs. The xylI gene encoding a putative xylanase was found upstream of the C. alkanolyticum xyloside transporter genes. A signal peptide was predicted at the N-terminus of the xylI-encoding polypeptide, which indicated XylI was a secreted protein. Recombinant mature XylI protein heterologously expressed in E. coli showed a xylanase activity toward xylans from various plant sources with optimum at pH 6.5, and C. glutamicum recombinant strain expressing native XylI released xylose, xylobiose, xylotriose, and arabino-xylobiose from arabinoxylan. Finally, introduction of the xylI gene into the C. glutamicum AXOS-utilizing strain enabled it to directly utilize arabinoxylan.     

Genome characteristics of the proteorhodopsin-containing marine flavobacterium <Emphasis Type="Italic">Polaribacter dokdonensis</Emphasis> DSW-5

Bacteria in the genus Polaribacter, belonging to the family Flavobacteriaceae, are typically isolated from marine environments. Polaribacter dokdonensis DSW-5, the type strain of the species, is a Gram-negative bacterium isolated from the East Sea of Korea. Whole genome shotgun sequencing was performed with the HiSeq 2000 platform and paired-end reads were generated at 188-fold coverage. The sequencing reads were assembled into two contigs with a total length of 3.08 Mb. The genome sequences of DSW-5 contain 2,776 proteincoding sequences and 41 RNA genes. Comparison of average nucleotide identities among six available Polaribacteria genomes including DSW-5 suggested that the DSW-5 genome is most similar to that of Polaribacter sp. MED152, which is a proteorhodopsin-containing marine bacterium. A phylogenomic analysis of the six Polaribacter strains and 245 Flavobacteriaceae bacteria confirmed a close relationship of the genus Polaribacter with Tenacibaculum and Kordia. DSW-5’s genome has a gene encoding proteorhodopsin and genes encoding 85 enzymes belonging to carbohydrate-active enzyme families and involved in polysaccharide degradation, which may play important roles in energy metabolism of the bacterium in the marine ecosystem. With genes for 238 CAZymes and 203 peptidases, DSW-5 has a relatively high number of degrading enzymes for its genome size suggesting its characteristics as a free-living marine heterotroph.     

<Emphasis Type="Italic">Ponticoccus alexandrii</Emphasis> sp. nov., a novel bacterium isolated from the marine toxigenic dinoflagellate <Emphasis Type="Italic">Alexandrium minutum</Emphasis>

During an investigation of the biodiversity of the cultivable bacterial community associated with paralytic shellfish poisoning toxin-producing marine dinoflagellate, Alexandrium minutum a novel algal-associated bacterium, designated strain AT2-A^T was isolated. 16S rRNA gene sequence similarity analysis showed that the strain is a member of the genus Ponticoccus, with high sequence similarity to Ponticoccus litoralis DSM 18986^T (97.9%) and Ponticoccus lacteus JCM 30379^T (96.0%). However, based on the data obtained for the physiological and biochemical characteristics, and low level of DNA–DNA relatedness analysis, the strain could be genotypically and phenotypically differentiated from two type strains of the genus Ponticoccus. Therefore, this algal-associated bacterial strain is concluded to represent a novel species of the genus Ponticoccus, for which the name Ponticoccus alexandrii sp. nov. is proposed. The type strain is AT2-A^T (CCTCC AB 2017228 ^T = KCTC 52626 ^T ).     

Intracellular Metabolic Changes of <Emphasis Type="Italic">Rhodococcus</Emphasis> sp. LH During the Biodegradation of Diesel Oil

In recent years, some marine microbes have been used to degrade diesel oil. However, the exact mechanisms underlying the biodegradation are still poorly understood. In this study, a hypothermophilous marine strain, which can degrade diesel oil in cold seawater was isolated from Antarctic floe-ice and identified and named as Rhodococcus sp. LH. To clarify the biodegradation mechanisms, a gas chromatography-mass spectrometry (GC-MS)-based metabolomics strategy was performed to determine the diesel biodegradation process-associated intracellular biochemical changes in Rhodococcus sp. LH cells. With the aid of partial least squares-discriminant analysis (PLS-DA), 17 differential metabolites with variable importance in the projection (VIP) value greater than 1 were identified. Results indicated that the biodegradation of diesel oil by Rhodococcus sp. LH was affected by many different factors. Rhodococcus sp. LH could degrade diesel oil through terminal or sub-terminal oxidation reactions, and might also possess the ability to degrade aromatic hydrocarbons. In addition, some surfactants, especially fatty acids, which were secreted by Rhodococcus into medium could also assist the strain in dispersing and absorbing diesel oil. Lack of nitrogen in the seawater would lead to nitrogen starvation, thereby restraining the amino acid circulation in Rhodococcus sp. LH. Moreover, nitrogen starvation could also promote the conversation of relative excess carbon source to storage materials, such as 1-monolinoleoylglycerol. These results would provide a comprehensive understanding about the complex mechanisms of diesel oil biodegradation by Rhodococcus sp. LH at the systematic level.     

<Emphasis Type="Italic">Oceanobacillus gochujangensis</Emphasis> sp. nov., isolated from <Emphasis Type="Italic">gochujang</Emphasis> a traditional Korean fermented food

A Gram-stain-positive, polar flagella-containing, rod-shaped, obligate aerobic, endospore-forming bacterium, strain TK1655^T, was isolated from the traditional Korean food gochujang. The 16S rRNA sequence of strain TK1655^T was a member of the genus Oceanobacillus similar to that of the type strain of Oceanobacillus oncorhynchi subsp. incaldanensis DSM 16557^T (97.2%), O. oncorhynchi subsp. oncorhynchi JCM 12661^T (97.1%), O. locisalsi KCTC 13253^T (97.0%), and O. sojae JCM 15792^T (96.9%). Strain TK1655^T was oxidase and catalase positive. Colonies were circular, smooth, low convex, cream in colour, and measured about 0.5–1.0 mm in diameter. The range for growth was 20–40°C (optimal, 30°C), pH 6.0–10.0 (optimal, 7.0), and 2–16% (w/v) NaCl (optimal, 2%). Additionally, the cells contained meso-DAP, and the predominant isoprenoid quinone was MK-7. The complex polar lipids were consisted of diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylcholine (PC). The major cellular fatty acid components were iso-C_15:0, anteiso-C_15:0, iso-C_16:0, and anteiso-C_17:0, and the DNA G+C content was 40.5%. DNA-DNA relatedness of our novel strain and reference strain O. locisalsi KCTC 13253^T, O. oncorhynchi subsp. incaldanensis DSM 16557^T, O. oncorhynchi subsp. oncorhynchi JCM 12661^T was 45.7, 43.8, and 41.9%. From the results of phenotypic, chemotaxonomic, and phylogenetic analyses of strain TK1655^T, we propose the novel species Oceanobacillus gochujangensis sp. nov. The type strain is TK1655^T (=KCCM 101304^T =KCTC 33014^T =CIP 110582^T =NBRC 109637^T).     

Isolation and characterization of a new fructophilic <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> FPL strain from honeydew

In the present study, a Lactobacillus plantarum FPL strain exhibiting fructophilic behavior has been isolated for the first time from honeydew. It is a probably syntrophic bacterium inhabiting the gastrointestinal tract of Coccus hesperidum L. and taking part in sugar metabolism. The promising growth characteristics and biochemical properties of Lb. plantarum FPL indicate that this may be a facultatively fructophilic species, whose properties are not associated with the loss of the alcohol/acetaldehyde dehydrogenase gene. The article attempts to classify the peculiar behavior of this strain by means of tests that are characteristic for FLAB as well as through a classic identification approach. In this study, we used a reference strain Lb. plantarum NRRL B-4496, which showed no fructophilic properties. With the FLAB group, the new strain shares the habit, such as a fructose-rich environment, the preference of this sugar for growth, and similar growth curves. However, it exceeds FLAB in terms of osmotolerance to high sugar content. The fructophilic Lb. plantarum FPL strain can proliferate and grow on a medium wherein the sugar concentration is 45 and 50% (w/v). Our findings indicate that honeydew can be a promising source of new fructophilic lactic acid bacteria.     

Comparison of two marine sponge-associated<Emphasis Type="Italic">Penicillium</Emphasis> strains DQ25 and SC10: differences in secondary metabolites and their bioactivities

Two strains ofPenicillium, DQ25 and SC10, isolated from marine spongeHaliclona angulata (Bowerbank) andHymeniacidon sp. respectively, were subjected to stationary cultivation under GYP medium for 30 days. The fermentation extracts were undergone bioactivities assays against human pathogens, phytopathogenic fungi and brine shrimp (Artemia salina). Bioassays-guided compounds isolation was performed by Silica gel columns and Sephadex LH-20 chromatography. Spectroscopic methods were used to structures elucidation of the compounds. Results showed the activities of secondary metabolites of strain DQ25 were generally stronger than that of strain SC10. Major bioactive molecules isolated from strain DQ25 were a 1,4-naphthoquinone derivative and an unidentified alkaloid. The two components were not isolated from the extract of strain SC10. ITS sequences revealed that these two species have the greatest similarity withPenicillium vinaceum andPenicillium granulatum respectively.     

Characterization of mycocin secreted by <Emphasis Type="Italic">Rhodotorula colostri</Emphasis> (Castelli) Lodder

A Rhodotorula colostri strain has been isolated that shows fungicidal activity against related species of the genera Rhodosporidium, Sporidiobolus, and their anamorphs phylogenetically belonging to the order Sporidiobolales (Microbotryomycetes, Pucciniomycotina). The agent secreted has a molecular weight of about 4–5 kDa, is active at pH values ranging from 3.5 to 5.5, and is thermolabile and protease-sensitive.     

Nitrogen-fixing cyanobacterium <Emphasis Type="Italic">Trichormus variabilis</Emphasis> of the Lake Baikal phytoplankton

A new filamentous cyanobacterial strain BAC 9610 was isolated from the lake Baikal pelagial. Data obtained by light, scanning, and transmission electron microscopy, along with 16S rRNA gene sequence analysis, allowed the bacterium identification as Trichormus variabilis, previously known as Anabaena variabilis. Trichormus is a cyanobacterial genus not presented in the list of Baikal plankton algae; A. variabilis also hasn’t been previously detected in Baikal phytoplankton. T. variabilis nitrogen fixation ability was demonstrated. The gene responsible for nitrogen fixation, nifH, was identified by PCR and was partially sequenced. No hepatotoxin synthesis genes were revealed in the strain.