Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology最新文献

Strain MP-1014^T, an obligate halophilic actinobacterium, was isolated from the mangrove soil of Thandavarayancholanganpettai, Tamil Nadu, India. A polyphasic approach was utilized to explore its phylogenetic position completely. The isolate was Gram-positive, filamentous, non-motile, and coccoid in older cultures. Ideal growth conditions were seen at 30 °C and pH 7.0, with 5% NaCl (W/V), and the DNA G + C content was 73.3%. The phylogenic analysis of this strain based upon 16S rRNA gene sequence revealed 97–99.8% similarity to the recognized species of the genus Isoptericola. Strain MP-1014^T exhibits the highest similarity to I. sediminis JC619^T (99.7%), I. chiayiensis KCTC19740^T (98.9%), and subsequently to I. halotolerans KCTC19646^T (98.6%), when compared with other members within the Isoptericola genus (< 98%). ANI scores of strain MP-1014^T are 86.4%, 84.2%, and 81.5% and dDDH values are 59.7%, 53.6%, and 34.8% with I. sediminis JC619^T, I. chiayiensis KCTC19740^T and I. halotolerans KCTC19646^T respectively. The major polar lipids of the strain MP-1014^T were phosphatidylinositol, phosphatidylglycerol, diphosphotidylglycerol, two unknown phospholipids, and glycolipids. The predominant respiratory menaquinones were MK₉ (H₄) and MK₉ (H₂). The major fatty acids were anteiso-C_15:0, anteiso-C_17:0, iso-C_14:0, C_15:0, and C_16:0. Also, initial genome analysis of the organism suggests it as a biostimulant for enhancing agriculture in saline environments. Based on phenotypic and genetic distinctiveness, the strain MP-1014 ^T represents the novel species of the genus Isoptericola assigned Isoptericola haloaureus sp. nov., is addressed by the strain MP-1014 ^T, given its phenotypic, phylogenetic, and hereditary uniqueness. The type strain is MP-1014^T [(NCBI = OP672482.1 = GCA_036689775.1) ATCC = BAA 2646^T; DSMZ = 29325^T; MTCC = 13246^T].

Two alkaliphilic, Gram‐stain-negative bacterial strains (MEB004^T and MEB108^T) were isolated from water samples collected from Lonar lake, India. The phylogenetic analysis of their 16S rRNA gene sequences showed the highest similarity to A. delamerensis DSM 18314^T (98.4%), followed by A. amylolytica DSM 18337^T and A. collagenimarina JCM 14267^T (97.9%). The genome sizes of strains MEB004^T and MEB108^T were determined to be 3,858,702 and 4,029,814 bp, respectively, with genomic DNA G + C contents of 51.4 and 51.9%. Average Nucleotide Identity, DNA–DNA Hybridization and Amino Acid Identity values between strains (MEB004^T and MEB108^T) and A. amylolytica DSM 18337^T were (82.3 and 85.5), (25.0 and 29.2) and (86.7 and 90.2%). Both novel strains produced industrially important enzymes, such as amylase, lipase, cellulase, caseinase, and chitinase at pH 10 evidenced by the genomic presence of carbohydrate-active enzymes encoding genes. Genomic analyses further identified pH tolerance genes, affirming their adaptation to alkaline Lonar Lake. Dominant fatty acids were Summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c), C_16:0, Summed feature 3, Sum In Feature 2 and C_12:0 3OH. The prevalent polar lipids included phosphatidyl ethanolamine, phosphatidyl glycerol, and diphosphatidyl glycerol. The major respiratory quinone was ubiquinone-8. Based on the polyphasic data, we propose the classification of strains MEB004^T and MEB108^T as novel species within the genus Alkalimonas assigning the names Alkalimonas mucilaginosa sp. nov. and Alkalimonas cellulosilytica sp. nov., respectively. The type strains are MEB004^T (= MCC 5208^T = JCM 35954^T = NCIMB 15460^T) and MEB108^T (= MCC 5330^T = JCM 35955^T = NCIMB 15461^T).

Two novel Gram-stain-negative strains designated P7^T and P8^T, were isolated from the soil of a paddy field in Goyang, Republic of Korea, and identified as new species within the genus Roseateles through a polyphasic taxonomic approach. These aerobic, rod-shaped, non-sporulating strains demonstrated optimal growth at 30 °C, pH 7, and in the absence of NaCl (0% w/v). Phylogenetic analysis based on 16S rRNA gene sequences indicated close relationships with Roseateles saccharophilus DSM654^T (98.7%) and Roseateles puraquae CCUG 52769^T (98.96%), respectively. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between the isolates with the most closely related strains with publicly available whole genomes were 82.0–85.5% and 25.0–30.2%, respectively. The predominant fatty acids identified were C_16:0 and summed feature 3 (composed of C_16:1 ω6c and/or C_16:1 ω7c), with minor amounts of C_12:0, C_10:0 3–OH and summed feature 8 (composed of C_18:1 ω7c and/or C_18:1 ω6c; 26.4%). Ubiquinone 8 was the main quinone, and the polar lipid profile included phosphatidylethanolamine, phosphatidylglycerol, two unidentified phosphoaminolipids, one unidentified phosphoglycolipid, three unidentified phospholipids, and one unidentified aminolipid. The draft genome sequences revealed genomic DNA G + C contents of 70.1% for P7^T and 68.2% for P8^T. Comprehensive physiological, biochemical, and 16S rRNA sequence analyses confirm these isolates as novel species of the genus Roseateles, proposed to be named Roseateles caseinilyticus sp. nov for strain P7^T (= KACC 22504^T = TBRC 15694^T) and Roseateles cellulosilyticus sp. nov. for strain P8^T (= KACC 22505^T = TBRC 15695^T).

Yersinia is an important genus comprising foodborne, zoonotic and pathogenic bacteria. On the other hand, species of the so-called group Yersinia enterocolitica-like are understudied and mostly characterized as non-pathogenic, despite of some reports of human infections. The present study aimed to provide genomic insights of Yersinia frederiksenii (YF), Yersinia intermedia (YI) and Yersinia kristensenii (YK) isolated worldwide. A total of 22 YF, 20 YI and 14 YK genomes were searched for antimicrobial resistance genes, plasmids, prophages, and virulence factors. Their phylogenomic relatedness was analyzed by Gegenees and core-genome multi-locus sequence typing. Beta-lactam resistance gene bla_TEM-116 and five plasmids replicons (pYE854, ColRNAI, ColE10, Col(pHAD28) and IncN3) were detected in less than five genomes. A total of 59 prophages, 106 virulence markers of the Yersinia genus, associated to adherence, antiphagocytosis, exoenzymes, invasion, iron uptake, proteases, secretion systems and the O-antigen, and virulence factors associated to other 20 bacterial genera were detected. Phylogenomic analysis revealed high inter-species distinction and four highly diverse YF clusters. In conclusion, the results obtained through the analyses of YF, YI and YK genomes suggest the virulence potential of these strains due to the broad diversity and high frequency of prophages and virulence factors found. Phylogenetic analyses were able to correctly distinguish these closely related species and show the presence of different genetic subgroups. These data contributed for a better understanding of YF, YI and YK virulence-associated features and global genetic diversity, and reinforced the need for better characterization of these Y. enterocolitica-like species considered non-pathogenic.

Kars Kashar cheese is an artisanal pasta-filata type cheese and geographically marked in Eastern Anatolia of Turkey. The aims of this research were to determine for the first time thermophilic lactic acid bacteria (LAB) of Kars Kashar cheese and characterize the technological properties of obtained isolates. In our research, a number of 15 samples of whey were collected from the different villages in Kars. These samples were incubated at 45 °C and used as the source material for isolating thermophilic LAB. A total of 250 colonies were isolated from thermophilic whey, and 217 of them were determined to be presumptive LAB based on their Gram staining and catalase test. A total of 170 isolates were characterized by their phenotypic properties and identified using the MALDI-TOF mass spectrometry method. Phenotypic identification of isolates displayed that Enterococcus and Lactobacillus were the predominant microbiota. According to MALDI-TOF MS identification, 89 isolates were identified as Enterococcus (52.35%), 57 isolates as Lactobacillus (33.53%), 23 isolates as Streptococcus (13.53%), and one isolate as Lactococcus (0.59%). All thermophilic LAB isolates were successfully identified to the species level and it has been observed that MALDI-TOF MS can be successfully used for the identification of selected LAB. The acidification and proteolytic activities of the isolated thermophilic LAB were examined, and the isolates designated for use as starter cultures were also genotypically defined.

Pseudoalteromonas piscicida 2515, isolated from Litopenaeus vannamei culture water, is a potential marine probiotic with broad anti-Vibrio properties. However, genomic information on P. piscicida 2515 is scarce. In this study, the general genomic characteristics and probiotic properties of the P. piscicida 2515 strain were analysed. In addition, we determined the antibacterial mechanism of this bacterial strain by scanning electron microscopy (SEM). The results indicated that the whole-genome sequence of P. piscicida 2515 contained one chromosome and one plasmid, including a total length of 5,541,406 bp with a G + C content of 43.24%, and 4679 protein-coding genes were predicted. Various adhesion-related genes, amino acid and vitamin metabolism and biosynthesis genes, and stress-responsive genes were found with genome mining tools. The presence of genes encoding chitin, bromocyclic peptides, lantibiotics, and sactipeptides showed the strong antibacterial activity of the P. piscicida 2515 strain. Moreover, in coculture with Vibrio anguillarum, P. piscicida 2515 displayed vesicle/pilus-like structures located on its surface that possibly participated in its bactericidal activity, representing an antibacterial mechanism. Additionally, 16 haemolytic genes and 3 antibiotic resistance genes, including tetracycline, fluoroquinolone, and carbapenem were annotated, but virulence genes encoding enterotoxin FM (entFM), cereulide (ces), and cytotoxin K were not detected. Further tests should be conducted to confirm the safety characteristics of P. piscicida 2515, including long-term toxicology tests, ecotoxicological assessment, and antibiotic resistance transfer risk assessment. Our results here revealed a new understanding of the probiotic properties and antibacterial mechanism of P. piscicida 2515, in addition to theoretical information for its application in aquaculture.

An aerobic, Gram-stain-negative, motile rod bacterium, designated as SYSU BS000021^T, was isolated from a black soil sample in Harbin, Heilongjiang province, China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belongs to the genus Methylobacterium, and showed the highest sequence similarity to Methylobacterium segetis KCTC 62267 ^T (98.51%) and Methylobacterium oxalidis DSM 24028 ^T (97.79%). Growth occurred at 20–37℃ (optimum, 28 °C), pH 6.0–8.0 (optimum, pH 7.0) and in the presence of 0% (w/v) NaCl. Polar lipids comprised of phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified aminolipid and one unidentified polar lipid. The major cellular fatty acids (> 5%) were C_18:0 and C_18:1 ω7c and/or C_18:1 ω6c. The predominant respiratory quinone was Q-10. The genomic G + C content was 68.36% based on the whole genome analysis. The average nucleotide identity (≤ 83.5%) and digital DNA–DNA hybridization (≤ 27.3%) values between strain SYSU BS000021^T and other members of the genus Methylobacterium were all lower than the threshold values recommended for distinguishing novel prokaryotic species. Based on the results of phenotypic, chemotaxonomic and phylogenetic analyses, strain SYSU BS000021^T represents a novel species of the genus Methylobacterium, for which the name Methylobacterium nigriterrae sp. nov. is proposed. The type strain of the proposed novel species is SYSU BS000021^T (= GDMCC 1.3814 ^T = KCTC 8051 ^T).

This brief review aims to draw attention to the biotechnological potential of actinomycetes. Their main uses as sources of antibiotics and in agriculture would be enough not to neglect them; however, as we will see, their biotechnological application is much broader. Far from intending to exhaust this issue, we present a short survey of the research involving actinomycetes and their applications published in the last 23 years. We highlight a perspective for the discovery of new active ingredients or new applications for the known metabolites of these microorganisms that, for approximately 80 years, since the discovery of streptomycin, have been the main source of antibiotics. Based on the collected data, we organize the text to show how the cosmopolitanism of actinomycetes and the evolutionary biotic and abiotic ecological relationships of actinomycetes translate into the expression of metabolites in the environment and the richness of biosynthetic gene clusters, many of which remain silenced in traditional laboratory cultures. We also present the main strategies used in the twenty-first century to promote the expression of these silenced genes and obtain new secondary metabolites from known or new strains. Many of these metabolites have biological activities relevant to medicine, agriculture, and biotechnology industries, including candidates for new drugs or drug models against infectious and non-infectious diseases. Below, we present significant examples of the antimicrobial spectrum of actinomycetes, which is the most commonly investigated and best known, as well as their non-antimicrobial spectrum, which is becoming better known and increasingly explored.