Devosia lacusdianchii sp. nov., an attached bacterium inhibited by metabolites from its symbiotic Microcystis.

A novel alphaproteobacterial strain JXJ CY 41T was isolated from a culture mass of Microcystis, collected from Lake Dianchi, south-west, China. Strain JXJ CY 41T was gram-strain-negative, aerobic, motile, with rod-shaped cells (0.4-1.0 × 1.7-3.5 µm). It was positive for catalase and starch hydrolysis, negative for oxidase and hydrolysis of Tweens (20, 40, and 80). Growth occurred at 10-44 °C, pH 5.0-10.0, and 0-5.0% (w/v) NaCl. Major fatty acids included C16:0 (28.1%), 11-methyl C18:1 ω7c (36.7%) and C18:1 ω7c (20.8%). Q10 was the sole ubiquinone. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, glycolipid, and an unidentified lipid. The DNA G + C content was 63.1%. Its 16S rRNA gene sequence showed high similarities with Devosia oryziradicis G19T (99.5%; not validly published), D. yakushimensis Yak96BT (98.3%) and D. ginsengisoli Gsoil 520T (98.1%), and less than 98.1% similarities with other members of the genus Devosia. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain JXJ CY 41T and its 5 closest similar strains were 19.9-24.1% and 75.7-80.5%, respectively. Based on the data above, strain JXJ CY 41T was identified as a novel species of the genus Devosia, for which the epithet Devosia lacusdianchii sp. nov. was proposed. The type strain is JXJ CY 41T (= KCTC 72812T = CGMCC 1.17502T). Strain JXJ CY 41T exhibited different interactions with Microcystis aeruginosa FACHB-905 (Maf) under different conditions, and Maf could control the bacterial cellular density by secreting unknown specific chemical compounds according to its nutritional requirements.

Maternal dominance contributes to subgenome differentiation in allopolyploid fishes.

Teleost fishes, which are the largest and most diverse group of living vertebrates, have a rich history of ancient and recent polyploidy. Previous studies of allotetraploid common carp and goldfish (cyprinids) reported a dominant subgenome, which is more expressed and exhibits biased gene retention. However, the underlying mechanisms contributing to observed 'subgenome dominance' remains poorly understood. Here we report high-quality genomes of twenty-one cyprinids to investigate the origin and subsequent subgenome evolution patterns following three independent allopolyploidy events. We identify the closest extant relatives of the diploid progenitor species, investigate genetic and epigenetic differences among subgenomes, and conclude that observed subgenome dominance patterns are likely due to a combination of maternal dominance and transposable element densities in each polyploid. These findings provide an important foundation to understanding subgenome dominance patterns observed in teleost fishes, and ultimately the role of polyploidy in contributing to evolutionary innovations.

GALA peptide improves the potency of nanobody-drug conjugates by lipid-induced helix formation.

A novel nanobody-drug conjugate (NDC) was constructed by incorporating an amphipathic peptide, GALA, which improved the cytotoxicity by one to two orders of magnitude. Mechanistic studies demonstrate that tethering to lipids induces GALA to form a helix, which dramatically enhances endocytosis. Our work provides a general strategy not only for improving the anti-cancer efficacy of protein-drug conjugates but also for increasing the efficiency of other types of endocytosis-dependent cell delivery.

Orbitides isolated from flaxseed induce apoptosis against SGC-7901 adenocarcinoma cells.

Unique plant-derived cyclic peptides family exhibiting various key biological activities has great possibility for anticancer therapy. In this study, we investigated the effects of orbitides isolated from flax (Linum usitatissimum L.) on the growth of SGC-7901 cancer cells and the potential mechanism. Results showed that flaxseed orbitides killed off cancer cells by inducing apoptosis in a dose-dependent manner, which was confirmed by the appearance of nuclear shrinkage and DNA fragmentation, and the inhibitory effect was stronger than that of pure orbitide [1-9-NαC]-linusorb B2 or [1-9-NαC]-linusorb B3. Besides, the mitochondrial apoptosis pathway-related protein cytochrome C (Cyt C) was released from mitochondria to cytosol, associated with the activation of caspases 9 and 3, and the cleavage of PARP. Taken together, these results indicated that flaxseed orbitides induced apoptosis via the mitochondrial pathway, releasing Cyt C, increasing Bax/Bcl-2 ratio and elevating the expression of cleaved caspase 9 and 3 in SGC-7901 cells.

ArgR directly inhibits lipA transcription in Pseudomonas protegens Pf-5.

ArgR, a transcriptional regulator belonging to the AraC/XylS family, plays a key role in arginine metabolism regulation. ArgR has also been found to repress the transcription of a lipase gene, but its molecular mechanism is still unknown. In this study, we investigated the molecular mechanism acting on the expression of intracellular lipase gene lipA regulated by ArgR in Pseudomonas protegens Pf-5 through knockout and overexpression of argR, detection of DNA-protein interaction in vivo, determining whole-cell lipase activities of various strains derived from Pf-5, and examining ß-galactosidase activities of various lacZ fusions. The results demonstrated that ArgR inhibits lipA expression at the transcriptional level. Further results showed that the inhibition of lipA transcription by ArgR is mediated by binding to the ArgR binding site of lipA promoter to produce steric hindrance, in which the common sequence, TGTCGC is crucial for the ArgR binding. Besides, arginine inhibits lipA expression in both wild-type and argR mutant, and shows a synergistic inhibition on lipA expression when combined with ArgR. To the best of our knowledge, this is the first report on ArgR directly repressing the transcription of a lipase gene.

Microbacterium lacusdiani sp. nov., a phosphate-solubilizing novel actinobacterium isolated from mucilaginous sheath of Microcystis.

A novel actinobacterium, designated strain JXJ CY 01T, was isolated from a mucilaginous sheath of Microcystis aeruginosa FACHB-905 collected from Lake Dianchi, south-west China. Taxonomic position of the isolate was determined by polyphasic approaches. Strain JXJ CY 01T shared 16S rRNA sequence similarities of 98.9 and 98.0% with Microbacterium marinilacus YM11-607T and Microbacterium paludicola US15T, and less than 98% with other members of the genus Microbacterium. The DNA-DNA relatedness values between strains JXJ CY 01T and M. marinilacus JCM 16546T and M. paludicola JCM 14308T were 53.5±1.4 and 53.8±2.1%, respectively. l-Ornithine was detected in the cell wall, and rhamnose, galactose, glucose, arabinose, fucose and mannose as signature sugars in the whole-cell hydrolysates. Other chemotaxonomic characteristics determined were MK-12 and MK-11 as predominant menaquinones, anteiso-C15:0, iso-C16:0, anteiso-C17:0 and iso-C17:0 as major cellular fatty acids (>10%), and diphosphatidylglycerol, phosphatidylglycerol, an unidentified glycolipid and two unidentified phospholipids as the polar lipids. The DNA G+C content was 70.4 mol%. On the basis of the above taxonomic data, strain JXJ CY 01T is determined to represent a novel species of the genus Microbacterium, for which the name Microbacterium lacusdiani sp. nov. is proposed. The type strain is JXJ CY 01T (= KCTC 29655T=DSM 29188T). The type strain JXJ CY 01T can solubilize both insoluble inorganic (calcium phosphate) and organic phosphate (l-α-phosphatidylcholine) and is possibly one of the mechanism for enhancement of growth of M. aeruginosa FACHB-905.

Citricoccus lacusdiani sp. nov., an actinobacterium promoting Microcystis growth with limited soluble phosphorus.

A novel actinobacterium, designated strain JXJ CY 21T, was isolated from the culture mass of Microcystis sp. FACHB-905 collected from Lake Dianchi, South-west China. Polyphasic taxonomic study revealed that the isolate should be a member of the genus Citricoccus. Comparison of the 16S rRNA gene sequence of strain JXJ CY 21T with the available sequences in the GenBank database showed that the strain is closely related to Citricoccus zhacaiensis FS24T (97.8 % similarity), Citricoccus parietis 02-Je-010T (97.7 %), Citricoccus terreus V3M1T (97.6 %), Citricoccus nitrophenolicus PNP1T (97.2 %), Citricoccus alkalitolerans YIM 70010T (97.2 %) and Citricoccus muralis 4-0T (97.0 %). The DNA-DNA hybridization values between strain JXJ CY 21T and the related type strains C. zhacaiensis FS24T and C. parietis 02-Je-010T were 16.0 ± 2.6 and 5.4 ± 1.7 %, respectively. The peptidoglycan in the cell wall was A4α type containing lysine-glutamic acid-glycine. The major respiratory menaquinone was found to be MK-8 (H2) (98.5 %), while the major cellular fatty acids (>10 %) were anteiso-C15:0, iso-C16:0, iso-C15:0 and iso-C14:0. The polar lipids detected were diphosphatidylglycerol, phosphatidylinositol, phosphatidylglycerol, an unidentified phospholipid and an unidentified glycolipid. The DNA G + C content was determined to be 62.7 mol%. Strain JXJ CY 21T can solubilize both insoluble inorganic and organic phosphates up to 24.7 and 1.7 mg/l respectively. This property of the novel actinobacterium acts as a modulator for enhancement of growth of Microcystis sp. FACHB-905 in the lake ecosystem where the amount of soluble phosphate is limited. On the basis of the above taxonomic data, strain JXJ CY 21T represents a novel species of the genus Citricoccus, for which the name Citricoccus lacusdiani sp. nov. is proposed. The type strain is JXJ CY 21T (=KCTC 29653T = DSM 29160T).

Modestobacter lacusdianchii sp. nov., a Phosphate-Solubilizing Actinobacterium with Ability to Promote Microcystis Growth.

A novel actinobacterium, designated strain JXJ CY 19T, was isolated from a culture mat of Microcystis aeruginosa FACHB-905 collected from Dianchi Lake, South-west China. 16S rRNA gene sequences comparison of strain JXJ CY 19T and the available sequences in the GenBank database showed that the strain was closely related to Modestobacter marinus 42H12-1T (99.1% similarity) and Modestobacter roseus KLBMP 1279T (99.0%). The isolate had meso-diaminopimelic in the cell wall with whole-cell sugars of mannose, rhamnose, ribose, glucose, galactose, and arabinose. The menaquinone detected was MK-9(H4), while the major cellular fatty acids include C17:1 ω8c, C15:0 iso, C15:1 iso G and C16:0 iso. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and an unidentified phospholipid. The DNA-DNA hybridization values between strains JXJ CY 19T and the closely related type strains Modestobacter marinus CGMCC 4.5581T and Modestobacter roseus NBRC 108673T were determined to be 50.8 ± 0.8% and 44.1 ± 1.7%, respectively. The DNA G+C content was 71.9 mol%. On the basis of the above taxonomic data and differences in physiological characters from the closely related type strains, strain JXJ CY 19T was recognized as a novel species of the genus Modestobacter, for which the name Modestobacter lacusdianchii sp. nov. (JXJ CY 19T = KCTC 39600T = CPCC 204352T) is proposed. The type strain JXJ CY 19T can solubilize calcium phosphate tribasic (Ca3(PO4)2), phytin and L-α-phosphatidylcholine. The phosphate-solubilizing property of the novel actinobacterium could be a possible factor for the increase in growth of Microcystis aeruginosa FACHB-905 in ecosystem where the amount of available soluble phosphate is limited such as Dianchi Lake.

Algicidal Activity of Streptomyces eurocidicus JXJ-0089 Metabolites and Their Effects on Microcystis Physiology.

UNLABELLED: Copper sulfate (CuSO4) has been widely used as an algicide to control harmful cyanobacterial blooms (CyanoHABs) in freshwater lakes. However, there are increasing concerns about this application, due mainly to the general toxicity of CuSO4 to other aquatic species and its long-term persistence in the environment. This study reported the isolation and characterization of two natural algicidal compounds, i.e., tryptamine and tryptoline, from Streptomyces eurocidicus JXJ-0089. At a concentration of 5 µg/ml, both compounds showed higher algicidal efficiencies than CuSO4 on Microcystis sp. FACHB-905 and some other harmful cyanobacterial strains. Tryptamine and tryptoline treatments induced a degradation of chlorophyll and cell walls of cyanobacteria. These two compounds also significantly increased the intracellular oxidant content, i.e., superoxide anion radical (O2 (-)) and malondialdehyde (MDA), but reduced the activity of intracellular reductants, i.e., superoxide dismutase (SOD), of cyanobacteria. Moreover, tryptamine and tryptoline treatments significantly altered the internal and external contents of microcystin-LR (MC-LR), a common cyanotoxin. Like CuSO4, tryptamine and tryptoline led to releases of intracellular MC-LR from Microcystis, but with lower rates than CuSO4 Tryptamine and tryptoline (5 µg/ml) in cyanobacterial cultures were completely degraded within 8 days, while CuSO4 persisted for months. Overall, our results suggest that tryptamine and tryptoline could potentially serve as more efficient and environmentally friendly alternative algicides than CuSO4 in controlling harmful cyanobacterial blooms. IMPORTANCE: Cyanobacterial harmful algal blooms (CyanoHABs) in aquatic environments have become a worldwide problem. Numerous efforts have been made to seek means to prevent, control, and mitigate CyanoHABs. Copper sulfate (CuSO4), was once a common algicide to treat and control CyanoHABs. However, its application has become limited due to concerns about its general toxicity to other aquatic species and its long-term persistence in the environment. There is a great need for algicides with higher specificity and low environmental impacts. This study reports the isolation and characterization of two natural algicidal compounds from a streptomycete strain, Streptomyces eurocidicus JXJ-0089. Our results suggest that the identified algicides could potentially serve as more efficient and environmentally friendly alternative algicides than CuSO4 in controlling harmful cyanobacterial blooms.

L-valine, an antialgal amino acid from Streptomyces jiujiangensis JXJ 0074(T).

An antialgal compound was isolated from the cultured broth of Streptomyces jiujiangensis JXJ 0074(T) by using bioassay methods. Based on the data of (1)H-NMR, (13)C-NMR, ESI-MS, and thin layer chromatography, the active compound was identified as L-valine, which showed antialgal activity mainly against Microcystis. L-valine exhibited greater antialgal activities than both L-lysine and copper sulfate (CuSO4) did on Microcystis aeruginosa lawn. However, M. aeruginosa recovered growth earlier with higher growth rate in L-valine treatment than in L-lysine treatment. L-valine dissipated completely within 2 days, much quicker than L-lysine (6 days), which resulted in the lysing of more than 80 % M. aeruginosa cells and the release of amount of intracellular microcystin-LR (MC-LR) within 2 days. As a resultant, the extracellular MC-LR content was more than twice of the control from day 1 to 5. Exposure to L-valine significantly promoted the synthesis of MC-LR. L-lysine also promoted the release and synthesis of MC-LR with much lesser efficiency than L-valine. L-valine could damage Microcystis severely, causing perforation and collapse of M. aeruginosa cells and decrease of the chlorophyll. The superoxide dismutase (SOD) activity in L-valine-treated cells of M. aeruginosa initially increased with 32.94 ± 3.37 % higher than the control after 36 h and then decreased quickly. However, the increase rate of superoxide anion radical (O2 (-)) was much higher than that of SOD, which resulted in serious lipid peroxidation and accumulation of malondialdehyde (MDA). To our knowledge, this is the first report showing L-valine active against cyanobacteria.

Streptomyces lushanensis sp. nov., a novel actinomycete with anti-cyanobacterial activity.

Strain JXJ 0135(T), an anti-cyanobacterial actinomycete, was isolated from a soil sample collected from Lushan Mountain, south China, and identified by using polyphasic approach. Phylogenetic analysis of the near-complete 16S rRNA gene sequence indicated that strain JXJ 0135(T) belongs to the genus Streptomyces and exhibited distinct subclade and also highest similarity (98.6%) to Streptomyces scopuliridis RB72(T). The strain developed well-branched substrate and aerial mycelia, and produced spiral spore chains. Spores were elliptical and the spore surface was smooth. The strain contained LL-diaminopimelic acid with whole-cell sugars of mannose, rhamnose, glucose and galactose. Phospholipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannosides, phosphotidylinositol dimannoside, an unidentified aminophospholipid and an unknown phospholipid. The menaquinones were MK-9(H6) and MK-9(H8). The major components of the fatty acids were anteiso-C15:0, iso-C16:0, anteiso-C17:0, iso-C15:0, C16:0, iso-C17:0 and iso-C14:0. The G+C content was 69.3 mol%. The DNA-DNA hybridization value between JXJ 0135(T) and S. scopuliridis RB72(T) was 41.2±1.4%. On the basis of the polyphasic data, strain JXJ 0135(T) represents a novel species of the genus Streptomyces, for which the name Streptomyces lushanensis sp. nov. is proposed. The type strain is JXJ 0135(T) (=DSM 42121(T)=JCM 19628(T)=KCTC 29261(T)=KACC 17834(T)=NRRL B-24994(T)).

Streptomyces jiujiangensis sp. nov., isolated from soil in South China.

An actinomycete capable of lysing cyanobacteria, strain JXJ 0074(T), was isolated from a soil sample collected from Jiangxi province, south China, and characterized by using polyphasic taxonomy. The new isolate showed morphological and chemotaxonomic properties typical of members of the genus Streptomyces. Phylogenetic analysis of the near-complete 16S rRNA gene sequence indicated that strain JXJ 0074(T) should be affiliated to the genus Streptomyces and exhibited highest similarities to Streptomyces shenzhenensis DSM 42034(T) (98.99 %) and Streptomyces lucensis NBRC 13056(T) (98.60 %), while the similarities to other members of the genus are lower than 98.22 % similarity. However, the DNA-DNA hybridization values between strain JXJ 0074(T) and S. shenzhenensis DSM 42034(T) or S. lucensis NBRC 13056(T) were 46.2 ± 2.6 and 32.6 ± 3.1 %, respectively. Thus, on the basis of the polyphasic data, strain JXJ 0074(T) represents a novel species of the genus Streptomyces, for which the name Streptomyces jiujiangensis sp. nov. is proposed. The type strain is JXJ 0074(T) (= BCRC 16953(T) = KCTC 29262(T)).