Proteomic insights into cold adaptation of psychrotrophic and mesophilic <Emphasis Type="Italic">Acidithiobacillus ferrooxidans</Emphasis> strains

Cold tolerant strains of Acidithiobacillus ferrooxidans play a role in metal leaching and acid mine drainage (AMD) production in northern latitude/boreal mining environments. In this study we used a proteomics and bioinformatics approach to decipher the proteome changes related to sustained growth at low temperatures to increase our understanding of cold adaptation mechanisms in A. ferrooxidans strains. Changes in protein abundance in response to low temperatures (5 and 15°C) were monitored and protein analyses of a psychrotrophic strain (D6) versus a mesophilic strain (F1) showed that both strains increased levels of 11 stress-related and metabolic proteins including survival protein SurA, trigger factor Tig, and AhpC-Tsa antioxidant proteins. However, a unique set of changes in the proteome of psychrotrophic strain D6 were observed. In particular, the importance of protein fate, membrane transport and structure for psychrotrophic growth were evident with increases in numerous chaperone and transport proteins including GroEL, SecB, ABC transporters and a capsule polysaccharide export protein. We also observed that low temperature iron oxidation coincides with a relative increase in the key iron metabolism protein rusticyanin, which was more highly expressed in strain D6 than in strain F1 at colder growth temperatures. We demonstrate that the psychrotrophic strain uses a global stress response and cold-active metabolism which permit growth of A. ferrooxidans in the extreme AMD environment in colder climates.     

Biodiscovery of new Australian thraustochytrids for production of biodiesel and long-chain omega-3 oils

Heterotrophic growth of thraustochytrids has potential in co-producing a feedstock for biodiesel and long-chain (LC, ≥C₂₀) omega-3 oils. Biodiscovery of thraustochytrids from Tasmania (temperate) and Queensland (tropical), Australia, covered a biogeographic range of habitats including fresh, brackish, and marine waters. A total of 36 thraustochytrid strains were isolated and separated into eight chemotaxonomic groups (A–H) based on fatty acid (FA) and sterol composition which clustered closely with four different genera obtained by 18S rDNA molecular identification. Differences in the relative proportions (%FA) of long-chain C₂₀, C₂₂, omega-3, and omega-6 polyunsaturated fatty acids (PUFA), including docosahexaenoic acid (DHA), docosapentaenoic acid, arachidonic acid, eicosapentaenoic acid (EPA), and saturated FA, as well as the presence of odd-chain PUFA (OC-PUFA) were the major factors influencing the separation of these groups. OC-PUFA were detected in temperate strains of groups A, B, and C (Schizochytrium and Thraustochytrium). Group D (Ulkenia) had high omega-3 LC-PUFA (53% total fatty acids (TFA)) and EPA up to 11.2% TFA. Strains from groups E and F (Aurantiochytrium) contained DHA levels of 50–61% TFA after 7 days of growth in basal medium at 20 °C. Groups G and H (Aurantiochytrium) strains had high levels of 15:0 (20–30% TFA) and the sum of saturated FA was in the range of 32–51%. β,β-Carotene, canthaxanthin, and astaxanthin were identified in selected strains. Phylogenetic and chemotaxonomic groupings demonstrated similar patterns for the majority of strains. Our results demonstrate the potential of these new Australian thraustochytrids for the production of biodiesel in addition to omega-3 LC-PUFA-rich oils.     

Biosynthesis of ω-alicyclic fatty acids induced by cyclic precursors and change of membrane fluidity in thermophilic bacteria <Emphasis Type="Italic">Geobacillus stearothermophilus</Emphasis> and <Emphasis Type="Italic">Meiothermus</Emphasis><Emphasis Type="Italic">ruber</Emphasis>

Two thermophilic strains belonging to Geobacillus stearothermophilus and Meiothermus ruber, which naturally do not synthesize ω-alicyclic fatty acids (ω-FAs) were cultivated with cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl carboxylic acids. Gas chromatography–mass spectrometry analysis of fatty acid methyl and picolinyl esters showed that both strains are able to synthesize ω-FAs when cultivated with the appropriate precursor. The incorporation of cyclic acids influenced the whole FA composition as well as membrane fluidity. Membrane fluidity of intact cells was studied by measuring the fluorescence polarisation of the probe l,6-diphenyl-1,3,5-hexatriene incorporated into membrane lipid bilayers. Cytoplasmic membrane became more fluid with increasing content of ω-FAs. This is caused by considerable changes in lipid packing within the membrane induced by the presence of ω-FAs not found in the natural environment of Geobacillus and Meiothermus strains.     

Influence of Phospholipid Species on Membrane Fluidity: A Meta-analysis for a Novel Phospholipid Fluidity Index

Generalized membrane lipid composition determinants of fluidity have been widely investigated, including phospholipid/cholesterol ratio and unsaturation index. Individual phospholipids differ in their physical characteristics, including their interaction with cholesterol and level of unsaturation, emphasizing the importance of examining their individual influence on membrane fluidity. Thus, the purpose of this study was to examine the dominant phospholipids of biological membranes (phosphatidylcholine, PC; phosphatidylethanolamine, PE; sphingomyelin, SM) through a meta-analysis to assess the validity of an inclusive phospholipid fluidity index (PFI = PC/(PE + SM)) as a determinant for membrane fluidity (expressed as polarization of fluorescent probe 1,6 diphenyl-1,3,5-hexatriene) in comparison to previous phospholipid ratios (PC/PE and PC/SM). The results demonstrate that all indices significantly predicted membrane fluidity at 25°C (based on 10–13 data points). In contrast, only PFI approached significance when predicting membrane fluidity at 37°C (P = 0.10 based on five points). As a result, PFI appears to be the only phospholipid index close to significantly predicting membrane fluidity at mammalian physiological temperature. Because this meta-analysis only assessed studies using mammalian membranes, future work should experimentally assess the validity of the PFI utilizing membranes from mammals and a variety of other species and tissues at their respective physiological temperatures.     

Virgibacillus zhanjiangensis sp. nov., a marine bacterium isolated from sea water

A Gram-positive, endospore-forming, catalase- and oxidase-positive, motile, rod-shaped, aerobic bacterium, designated strain JSM 079157^T, was isolated from surface seawater off the coastline of Naozhou Island in South China Sea. The organism was able to grow with 1–15% (w/v) total salts (optimum, 4–7%), and at pH 6.0–10.0 (optimum, pH 7.5) and 10–45°C (optimum, 30°C). meso-Diaminopimelic acid was present in the cell-wall peptidoglycan. The predominant menaquinone was MK-7, and the polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The major cellular fatty acids were anteiso-C_15:0 (45.1%) and anteiso-C_17:0 (16.2%), and the DNA G + C content was 39.5 mol%. A phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain JSM 079157^T should be assigned to the genus Virgibacillus, being related most closely to the type strains of Virgibacillus litoralis (97.4% sequence similarity), Virgibacillus necropolis (97.3%) and Virgibacillus carmonensis (97.1%). These four strains formed a distinct subcluster in the phylogenetic tree. The levels of DNA–DNA relatedness between the new isolate and the type strains of V. litoralis, V. necropolis and V. carmonensis were 30.4, 19.3 and 12.6%, respectively. The results of the phylogenetic analysis, combined with DNA–DNA relatedness data, phenotypic characteristics and chemotaxonomic information, support the suggestion that strain JSM 079157^T represents a new species of the genus Virgibacillus, for which the name Virgibacillus zhanjiangensis sp. nov. is proposed. The type strain is JSM 079157^T (=DSM 21084^T = KCTC 13227^T).     

Identification and characterization of a new monoamine oxidase type C-like dehydratase from Phytophthora capsici involved in polyhydroxyalkanoates biosynthesis

A new monoamine oxidase type C-like dehydratase gene (MaoC) supplying (R)-3-hydroxyacyl-CoA from the fatty acid oxidation pathway to polyhydroxyalkanoates (PHAs) biosynthetic pathways was identified from Phytophthora capsici. MaoC was over-expressed in Escherichia coli and the recombinant MaoC was purified. The purified tagged MaoC shows the enoyl-CoA hydratase activity of 58 U/mg towards crotonyl-CoA. MaoC may not fold properly above 40°C which was revealed by circular dichroism analysis. Crystal of MaoC diffracts to 2.9 ? in space group P2₁2₁2₁, with unit-cell parameters a = 81.5 ?, b = 82.6 ?, c = 124.2 ?, α = β = γ = 90°.     

<Emphasis Type="Italic">Marinobacter zhanjiangensis</Emphasis> sp. nov., a marine bacterium isolated from sea water of a tidal flat of the South China Sea

A novel Gram-negative, catalase- and oxidase-positive, non-sporulating, rod-shaped, aerobic bacterium, designated strain JSM 078120^T, was isolated from sea water collected from a tidal flat of Naozhou Island, South China Sea. Growth occurred with 1–15% (w/v) total salts (optimum, 2–4%), at pH 6.0–10.0 (optimum, pH 7.5) and at 4–35°C (optimum, 25–30°C). The major cellular fatty acids were C_18:1 ω9c, C_16:0, C_12:0 3-OH and C_16:1 ω7c. The predominant respiratory quinone was ubiquinone Q-9, and the genomic DNA G + C content was 60.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JSM 078120^T should be assigned to the genus Marinobacter, being related most closely to the type strains of Marinobacter segnicrescens (sequence similarity 98.2%), Marinobacter bryozoorum (97.9%) and Marinobacter gudaonensis (97.6%). The sequence similarities between the novel isolate and the type strains of other recognized Marinobacter species ranged from 96.7 (with Marinobacter salsuginis) to 93.3% (with Marinobacter litoralis). The levels of DNA–DNA relatedness between strain JSM 078120^T and the type strains of M. segnicrescens, M. bryozoorum and M. gudaonensis were 25.3, 20.6 and 18.8%, respectively. The combination of phylogenetic analysis, DNA–DNA relatedness, phenotypic characteristics and chemotaxonomic data supported the view that strain JSM 078120^T represents a novel species of the genus Marinobacter, for which the name Marinobacter zhanjiangensis sp. nov. is proposed. The type strain is JSM 078120^T (= CCTCC AB 208029^T = DSM 21077^T = KCTC 22280^T). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain JSM 078120^T is FJ425903.     

<Emphasis Type="Italic">Singulispaera mucilagenosa</Emphasis> sp. nov., a novel acid-tolerant representative of the order <Emphasis Type="Italic">Planctomycetales</Emphasis>

Two novel strains of budding bacteria, Z-0071^T and Z-0072, were isolated from dystrophic humified waters formed by xylotrophic fungi in the course of spruce wood degradation. The cells of both strains are coccoid (0.95–1.80 μm), nonmotile, single or arranged in pairs. The cells have a complex system of intracellular membranes and are covered with fimbriae and surrounded by a mucous capsule up to 0.3 μm thick. Both strains are aerobic organoheterotrophic, mesophilic, and acid-tolerant microorganisms that are able to grow under microaerobic conditions. They utilize N-acetyl-glucosamine, carbohydrates, and lactate as growth substrates. The strains grow in a pH range of 4.0–7.5 with an optimum at 6.0–6.5. The temperature range for growth is 4–30°C, with an optimum at 25–28°C. Strains Z-0071^T and Z-0072, inhabitants of dystrophic low-mineral waters, are NaCl-sensitive: the NaCl content in the media above 0.5 g/l inhibited growth. The main fatty acids of strains Z-0071^T and Z-0072 are C_16:0, C_18:1ω9c, and C_{18:2ω9c, 12c}. The DNA G + C base content is 51.2–51.7 mol %. The sequences of the 16S rRNA gene fragments (1310 bp) of strains Z-0071^T and Z-0072 were found to be identical. The obtained sequences showed a 94.3% similarity with the sequences of the type strain of the most closely related species Singulisphaera acidiphila MOB10≅T. The phenotypic and phylogenetic properties of strains Z-0071^T and Z-0072 support classification of these strains within the genus Singulisphaera as a new species Singulisphaera mucilagenosa sp. nov., with the type strain Z-0071^T (VKM B-2626).     

Oleispira lenta sp. nov., a novel marine bacterium isolated from Yellow sea coastal seawater in Qingdao, China

The taxonomic position of strain DFH11^T, which was isolated from coastal seawater off Qingdao, People’s Republic of China in 2007, was determined. Strain DFH11^T comprised Gram-negative, motile, strictly aerobic spirilli that did not produce catalase. Comparative 16S rRNA gene sequence analysis revealed that strain DFH11^T shared ~97.2, 93.3, 91.8, 91.7 and 91.5% sequence similarities with Oleispira antarctica, Spongiispira norvegica, Bermanella marisrubri, Oceaniserpentilla haliotis and Reinekea aestuarii, respectively. DNA–DNA hybridization experiments indicated that the strain was distinct from its closest phylogenetic neighbour, O. antarctica. The strain grew optimally in 2–3% (w/v) NaCl, at pH 5.0–10.0 (optimally at pH 7.0) and between 0 and 30°C (optimum growth temperature 28°C). The strain exhibited a restricted substrate profile, with a preference for aliphatic hydrocarbons, that is consistent with its closest phylogenetic neighbour O. antarctica. Growth of the isolate at different temperatures affected the cellular fatty acid profile. 28°C cultured cells contained C_16:1ω7c and/or iso-C_15:0 2-OH (50.4%) and C_16:0 (19.2%) as the major fatty acids. However, the major fatty acids of the cells cultured at 4°C were C_16:1ω7c and/or C_16:1ω6c (40.2%), C_16:0 (17.2%) and C_17:1ω8c (10.1%). The G+C content of the genomic DNA was 42.7 mol%. Phylogeny based on 16S rRNA gene sequences together with data from DNA–DNA hybridization, phenotypic and chemotaxonomic characterization revealed that DFH11^T should be classified as a novel species of the genus Oleispira, for which the name Oleispira lenta sp. nov. is proposed, with the type strain DFH11^T (=NCIMB 14529^T = LMG 24829^T).     

<Emphasis Type="Italic">Halobacillus hunanensis</Emphasis> sp. nov., a moderately halophilic bacterium isolated from a subterranean brine

A moderately halophilic, Gram-positive, catalase- and oxidase-positive, rod-shaped, aerobic bacterium, designated strain JSM 071077^T, was isolated from a subterranean brine sample collected from a salt mine in Hunan Province, China. Cells were motile by means of peritrichous flagella and formed ellipsoidal endospores lying in subterminal swollen sporangia. Strain JSM 071077^T was able to grow with 2–25% (w/v) total salts (optimum, 5–10%), at pH 6.0–10.0 (optimum, pH 7.5) and 10–40°C (optimum, 25–30°C). meso-Diaminopimelic acid was present in the cell-wall peptidoglycan. The predominant menaquinone was MK-7, and the major cellular fatty acids were anteiso-C_15:0, anteiso-C_17:0 and iso-C_15:0. The genomic DNA G+C content was 41.8 mol%. Phylogenetic analyses based on 16S rRNA gene sequence comparisons revealed that strain JSM 071077^T should be assigned to the genus Halobacillus, being related most closely to the type strain of Halobacillus naozhouensis (98.8% sequence similarity), and the two strains formed a distinct subline in the neighbor-joining, minimum-evolution and maximum-parsimony phylogenetic trees. The sequence similarities between the novel isolate and the type strains of other recognized Halobacillus species ranged from 97.6% (with Halobacillus alkaliphilus) to 95.2% (with Halobacillus kuroshimensis). The results of the phylogenetic analyses, combined with DNA–DNA relatedness data, phenotypic characteristics and chemotaxonomic information, support that strain JSM 071077^T represents a new species of the genus Halobacillus, for which the name Halobacillus hunanensis sp. nov. is proposed. The type strain is JSM 071077^T (=DSM 21184^T = KCTC 13235^T).     

Heptanol-induced decrease in cardiac gap junctional conductance is mediated by a decrease in the fluidity of membranous cholesterol-rich domains

To assess whether alterations in membrane fluidity of neonatal rat heart cells modulate gap junctional conductance (g _j ), we compared the effects of 2mm 1-heptanol and 20 μm 2-(methoxyethoxy)ethyl 8-(cis-2-n-octylcyclopropyl)-octanoate (A₂C) in a combined fluorescence anisotropy and electrophysiological study. Both substances decreased fluorescence steady-state anisotropy (r_ss), as assessed with the fluorescent probe 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) by 9.6±1.1% (mean ±sem,n=5) and 9.8±0.6% (n=5), respectively, i.e., both substances increased bulk membrane fluidity. Double whole-cell voltage-clamp experiments showed that 2mm heptanol uncoupled cell pairs completely (n=6), whereas 20 μm A₂C, which increased bulk membrane fluidity to the same extent, did not affect coupling at all (n=5). Since gap junction channels are embedded in relatively cholesterol-rich domains of the membrane, we specifically assessed the fluidity of the cholesterol-rich domains with dehydroergosterol (DHE). Using DHE, heptanol increased r_ss by 14.9±3.0% (n=5), i.e., decreased cholesterol domain fluidity, whereas A₂C had no effect on r_ss (−0.4±6.7%,n=5). Following an increase of cellular “cholesterol” content (by loading the cells with DHE), 2mm heptanol did not uncouple cell pairs completely:g _j decreased by 80±20% (range 41–95%,n=5). The decrease ing _j was most probably due to a decrease in the open probability of the gap junction channels, because the unitary conductances of the channels were not changed nor was the number of channels comprising the gap junction. The sensitivity of non-junctional membrane channels to heptanol was unaltered in cholesterol-enriched myocytes. These results indicate that the fluidity of cholesterol-rich domains is of importance to gap junctional coupling, and that heptanol decreasesg _j by decreasing the fluidity of cholesterol-rich domains, rather than by increasing the bulk membrane fluidity.     

Zhihengliuella salsuginis sp. nov., a moderately halophilic actinobacterium from a subterranean brine

A novel moderately halophilic, alkaliphilic, non-motile, non-sporulating, catalase-positive, oxidase-negative, aerobic, coccus-shaped, Gram-positive bacterium, designated strain JSM 071043^T, was isolated from a subterranean brine sample collected from a salt mine in Hunan Province, China. Growth occurred with 0.5–20% (w/v) NaCl (optimum 5–10%) at pH 6.5–10.5 (optimum pH 8.5) and at 10–40°C (optimum 25–30°C). Good growth also occurred in the presence of 0.5–20% (w/v) KCl (optimum 5–8%) or 0.5–25% (w/v) MgCl₂·6H₂O (optimum 5–10%). The peptidoglycan type was A4α (l-Lys–l-Ala–l-Glu) and major cell-wall sugars were tyvelose and mannose. The major cellular fatty acids were anteiso-C_15:0, iso-C_16:0 and anteiso-C_17:0. Strain JSM 071043^T contained MK-9 and MK-8 as the predominant menaquinones and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol as the major polar lipids. The DNA G + C content was 67.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JSM 071043^T was a member of the suborder Micrococcineae, and was most closely related to Zhihengliuella halotolerans YIM 70185^T (sequence similarity 98.9%) and Zhihengliuella alba YIM 90734^T (98.2%), and the three strains formed a distinct branch in the phylogenetic tree. The combination of phylogenetic analysis, DNA–DNA relatedness values, phenotypic characteristics and chemotaxonomic data supports the proposal that strain JSM 071043^T represents a novel species of the genus Zhihengliuella, for which the name Z. salsuginis sp. nov. is proposed. The type strain is JSM 071043^T (= DSM 21149^T = KCTC 19466^T).     

Metschnikowia saccharicola sp. nov. and Metschnikowia lopburiensis sp. nov., two novel yeast species isolated from phylloplane in Thailand

A Gram-negative, facultatively anaerobic, motile by means of single polar flagellum, rod-shaped marine bacterium, designated strain E414, was isolated from sea water collected from a farming pond rearing marine shrimp Litopenaeus vannamei in Zhanjiang, Guangdong province, PRC. The strain was able to grow in the presence of 0.5–6% (w/v) NaCl (optimally in 3–6% (w/v) NaCl), between pH 6 and 9 (optimally at pH 7–8), between 15 and 37°C (optimally at 25–30°C). Phylogenetic analysis based on 16S rRNA gene sequences locate strain E414 in the vicinity of the coralliilyticus clade within the genus Vibrio. DNA–DNA relatedness data and multigene phylogenetic analysis based on the concatenated sequences of four genes (16S rRNA, rpoA, recA and pyrH) clearly differentiated strain E414 from its closest phylogenetic neighbours. Analysis of phenotypic features, including enzyme activities and utilization and fermentation of various carbon sources, further revealed discrimination between strain E414 and phylogenetically related Vibrio species. The major fatty acid components are C_16:1ω6c and/or C_16:1ω7c (27.4%), C_18:1ω7c and/or C_18:1ω6c (19.3%) and C_16:0 (18.2%). The DNA G+C content of strain E414 was 38.7 mol%. Based on phenotypic, chemotaxonomic, phylogenetic and DNA–DNA relatedness values, it can be concluded that E414 should be placed in the genus Vibrio as representing a novel species, for which the name Vibrio zhanjiangensis sp. nov. is proposed, with the type strain E414 (=CCTCC AB 2011110^T = NBRC 108723^T = DSM 24901).     

<Emphasis Type="Italic">Halomonas sediminis</Emphasis> sp. nov., a new halophilic bacterium isolated from salt-lake sediment in China

A novel Gram-negative, slightly halophilic, catalase- and oxidase-positive, obligately aerobic bacterium, strain YIM-C248^T, was isolated from a sediment sample collected from a salt-lake in the Qaidam Basin in Qinghai, north-west China. Cells were non-sporulating short rods, occurring singly or as doublets, motile with peritrichous flagella. Growth occurred with 1–15% (w/v) NaCl [optimum 2–4% (w/v) NaCl], at pH 6.0–10.0 (optimum pH 7.5) and at 4–35°C (optimum 25–30°C). The major cellular fatty acids were C_18:1 ω7c, C_12:0 3-OH, cyclo C_19:0 ω8c, C_16:0 and C_16:1. The predominant respiratory quinone was Q-9 and the genomic DNA G + C content was 58.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YIM-C248^T should be assigned to the genus Halomonas. The sequence similarities between the isolate and the type strains of members of the genus Halomonas were in the range of 92.5–97.5%. The combination of phylogenetic analysis, DNA–DNA hybridization data, phenotypic characteristics and chemotaxonomic differences supported the view that strain YIM-C248^T represents a new species of the genus Halomonas, for which the name Halomonas sediminis sp. nov. is proposed, with YIM-C248^T (=CCTCC AA 207031 = KCTC 22167) as the type strain. The GenBank/EMBL/DBBJ accession number for the 16S rRNA gene sequence of strain YIM-C248^T is EU135707.     

Alkalilactibacillus ikkensis, gen. nov., sp. nov., a novel enzyme-producing bacterium from a cold and alkaline environment in Greenland

Three novel Gram-positive, endospore-forming bacteria were isolated from a cold and alkaline environment. Phylogenetic analysis showed that the strains were almost identical, and that they were related to Natronobacillus azotifigens 24KS-1^T (95.8% identity), Paraliobacillus quinghaiensis YIM-C158^T (95.1%), Paraliobacillus ryukyuensis O15-7^T (94.5%), and Halolactibacillus miurensis M23-1^T (93.9%). The isolates produced amylase, α-galactosidase, β-galactosidase, and β-glucuronidase, and showed optimal growth at pH 10, at 20°C, and at 2–8% (w/v) NaCl. Major fatty acids were C_14:0 (10.6–11.6%), anteiso-C_15:0 (25.7–32.7%), C_16:1 ω11c (12.2–16.0%), and C_16:0 (14.0–20.4%). The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol, and meso-diaminopimelic acid was found in the cell-wall peptidoglycan. The G+C content was 38.4%. DNA–DNA hybridization between strain GCM68^T and H. miurensis M23-1^T was 32.4%, while hybridization to N. azotifigens 24KS-1^T, Amphibacillus tropicus Z-7792^T, and Paraliobacillus ryukyuensis O15-7^T was below 30%. The phylogenetic analysis and G+C content place strain GCM68^T in relation to species belonging to Bacillus rRNA group 1, but phylogenetic and physiologic data combined with chemotaxonomic analyses support our proposal for a new genus, Alkalilactibacillus, gen. nov., with the novel species Alkalilactibacillus ikkensis, sp. nov. (type strain is GCM68^T = DSM 19937 = LMG 24405).     

Improvement of lipid production in the marine strains Alexandrium minutum and Heterosigma akashiwo by utilizing abiotic parameters

Two different strains of microalgae, one raphidophyte and one dinoflagellate, were tested under different abiotic conditions with the goal of enhancing lipid production. Whereas aeration was crucial for biomass production, nitrogen deficiency and temperature were found to be the main abiotic parameters inducing the high-level cellular accumulation of neutral lipids. Net neutral lipid production and especially triacylglycerol (TAG) per cell were higher in microalgae (>200% in Alexandrium minutum, and 30% in Heterosigma akashiwo) under treatment conditions (25°C; 330 μM NaNO₃) than under control conditions (20°C; 880 μM NaNO₃). For both algal species, oil production (free fatty acids plus TAG fraction) was also higher under treatment conditions (57 mg L⁻¹ in A. minutum and 323 mg L⁻¹ in H. akashiwo). Despite the increased production and accumulation of lipids in microalgae, the different conditions did not significantly change the fatty acids profiles of the species analyzed. These profiles consisted of saturated fatty acids (SAFA) and polyunsaturated fatty acids (PUFA) in significant proportions. However, during the stationary phase, the concentrations per cell of some PUFAs, especially arachidonic acid (C20:4n6), were higher in treated than in control algae. These results suggest that the adjustment of abiotic parameters is a suitable and one of the cheapest alternatives to obtain sufficient quantities of microalgal biomass, with high oil content and minimal changes in the fatty acid profile of the strains under consideration.     

Nocardioides panzhihuaensis sp. nov., a novel endophytic actinomycete isolated from medicinal plant Jatropha curcas L.

A novel Gram-positive, aerobic, rod-shaped and mycelia-producing bacterial strain, designated KLBMP 1050^T, was isolated from the stem of the oil-seed plant Jatropha curcas L. collected from Sichuan Province, south-west China. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the isolate KLBMP 1050^T belonged to the genus Nocardioides, with the highest sequence similarity to Nocardioides albus KCTC 9186^T (99.38 %) and Nocardioides luteus KCTC 9575^T (99.03 %). However, the DNA–DNA relatedness of isolate KLBMP 1050^T to these two type strains were 37.5 ± 3.5 and 33 ± 2.3 %, respectively. Strain KLBMP 1050^T grew at the pH range 6–11, temperature range 10–32 °C and with 0–12 % NaCl. The physiological properties of strain KLBMP 1050^T differ from those of N. albus KCTC 9186^T and N. luteus KCTC 9575^T. The cell-wall peptidoglycan contained ll-diaminopimelic acid and MK-8(H₄) was the major respiratory quinone. The predominant cellular fatty acid of strain KLBMP 1050^T was iso-C_16:0 (23.3 %). The total DNA G+C content was 70.1 mol%. On the basis of the phenotypic, chemotaxonomic and phylogenetic data, strain KLBMP 1050^T represents a novel species of the genus Nocardioides, for which the name Nocardioides panzhihuaensis sp. nov. is proposed. The type strain is KLBMP 1050^T (= KCTC 19888^T = NBRC 108680^T).     

Effects of temperature and initial pH on biohydrogen production from food-processing wastewater using anaerobic mixed cultures

This study attempted to determine the optimal temperature and initial cultivation pH by conducting a series of batch tests in stirred-tank bioreactor using fructose-producing wastewater as an organic substrate. The bioreactor temperature was controlled at 35–55°C with an initial pH of 4–8. Hydrogen production efficiency was assessed using specific hydrogen production potential (SHPP) and the maximum specific hydrogen production rate (SHPR_m). Experimental results indicated that temperature and initial pH markedly affected SHPP and SHPR_m, volatile fatty acids distribution as well as the ratio of butyrate/acetate (BHu/HAc). Two-fold higher SHPP and SHPR_m were obtained at thermophilic condition (55°C) than those at mesophilic condition (35°C). The optimal initial pH was 6 for hydrogen production with peak values of SHPP of 166.8 ml-H₂/g-COD and SHPR_m of 26.7 ml-H₂/g-VSS-h for fructose-processing wastewater. Molasses-processing wastewater had a higher SHPP (187.0 ml-H₂/g-COD) and SHPR_m (42.7 ml-H₂/gVSS-h) than fructose-processing wastewater at pH 6. The DGGE profiles indicated that molasses-processing wastewater is a better substrate than fructose-processing wastewater for growth of hydrogen-producing bacteria due to the high staining intensity of bands.     

<Emphasis Type="Italic">Yaniella soli</Emphasis> sp. nov., a new actinobacterium isolated from non-saline forest soil in China

A novel Gram-stain-positive, slightly halophilic, facultatively alkaliphilic, non-motile, non-sporulating, catalase-positive, oxidase-negative, aerobic bacterium, designated strain JSM 070026^T, was isolated from non-saline forest soil in China. Growth occurred with 0–20% (w/v) NaCl (optimum, 2–4%) and at pH 6.0–10.5 (optimum, pH 8.0) and 5–40°C (optimum, 30°C). Good growth also occurred in the presence of 0–28% (w/v) KCl (optimum, 2–5%) or 0–25% (w/v) MgCl₂·6H₂O (optimum, 1–4%). The peptidoglycan type was A4α (l-Lys–Gly–l-Glu). Cell-wall sugars contained mannose and xylose. The major cellular fatty acids were anteiso-C15:0 and iso-C15:0. Strain JSM 070026^T contained menaquinone 8 as the major respiratory quinone and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol as the major polar lipids. The DNA G + C content of strain JSM 070026^T was 56.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JSM 070026^T was a member of the suborder Micrococcineae and most closely related to Yaniella flava YIM 70178^T (sequence similarity 99.4%) and Yaniella halotolerans YIM 70085^T (97.9%). The three strains formed a distinct branch in the phylogenetic tree. The combination of phylogenetic analysis, DNA–DNA relatedness values, phenotypic characteristics and chemotaxonomic data supports the proposal that strain JSM 070026^T represents a novel species of the genus Yaniella, for which the name Yaniella soli sp. nov. is proposed. The type strain is JSM 070026^T (=DSM 22211^T = KCTC 13527^T).     

Temperature influences the performance and effectiveness of field and laboratory strains of the ichneumonid parasitoid, <Emphasis Type="Italic">Campoletis chlorideae</Emphasis>

To understand the influence of temperature on host–parasitoid interactions as a consequence of climatic change, we studied development, survival, and fecundity of field and laboratory strains of the Helicoverpa armigera larval endoparasitoid, Campoletis chlorideae at five different temperatures under laboratory conditions. Post-embryonic development period and degree-days required for completing the life cycle by both the strains decreased by 2.5 and 1.5 folds at 27°C compared to 18°C. Post embryonic development period showed a negative (r = −0.99, P < 0.001) and the development rate a positive (r = 0.99, P < 0.001) association with an increase in temperature. However, no parasitoid larvae survived in H. armigera larvae reared at 12 and 35°C after parasitization, suggesting that temperatures ≥35°C as a result of global warming will be lethal for development and survival of immature stages of C. chlorideae. Adult longevity was negatively associated (r = −0.91 to −0.96, P < 0.001) with temperatures between 12 and 35°C. The parasitoid adults stored at 12°C survived for longer period and exhibited higher fecundity than those kept at 27°C, but the efficiency of parasitism and adult emergence were quite low. Sex ratio of the progeny at 12°C was highly male-biased than the insects kept at 27°C. Laboratory strain of the parasitoid exhibited better survival, and the adults lived longer than the field strain at 18°C than at 27°C. Therefore, C. chlorideae adults stored at 18°C could be used for parasitism, while the immature stages should be reared at 27°C for mass production of the parasitoid for biological control of H. armigera.