Pedobacter rhodius sp. nov. and Pedobacter punctiformis sp. nov., isolated from soil

Two Gram-staining negative, catalase- and oxidase-positive, pinkish-colored and rod-shaped strains, designated SJ11T and HCMS5-2 T, were isolated from soil in South Korea. The growth of strain SJ11T was observed from 15℃ to 35℃ (optimum, 30℃), from pH 6.0 to 11.0 (optimum, pH 6.0-7.0) and with NaCl 0-1% (w/v) (optimum, 0%) and that of strain HCMS5-2 T was observed from 4℃ to 40℃ (optimum, 25℃), from pH 6.0 to pH 8.0 (optimum, pH 7.0) and with NaCl 0-5% (w/v) (optimum, 0-1%). Phylogenetic analysis based on 16S rRNA gene sequences showed that both strains belonged to the genus Pedobacter. Strain SJ11T had the highest 16S rRNA similarities with Pedobacter jejuensis THG-DR3T (98.5%) and strain HCMS5-2 T had the highest similarities with Pedobacter nototheniae 36B243T (98.7%). The digital DNA-DNA hybridization value of strain SJ11T with Pedobacter jejuensis THG-DR3T was 23.6%, with an average nucleotide identity value of 79.6%, and that of strain HCMS5-2 T with Pedobacter nototheniae 36B243T was 26.4%, with an average nucleotide identity value of 83.1%. The predominant cellular fatty acids (> 10%) of SJ11T and HCMS5-2 T were iso-C15:0, summed feature 3 (comprising C16:1ω7c and/or C16:1ω6c) and iso-C17:0 3-OH. The genome size of strain SJ11T was approximately 4.7 Mb with a G + C content of 37.7% and that of strain HCMS5-2 T was approximately 4.1 Mb with a G + C content of 36.4%. The major polar lipid and respiratory quinone of SJ11T and HCMS5-2 T were phosphatidylethanolamine and menaquinone NK-7, respectively. Results of this study showed that strains SJ11T and HCMS5-2 T belonged to the genus Pedobacter as novel species, of which the name Pedobacter rhodius sp. nov., with the type strain SJ11T (= KACC 22884 T = TBRC 16597 T) and Pedobacter punctiformis sp. nov., with the type strain HCMS5-2 T (= KACC 22863 T = TBRC 16598 T) were respectively proposed.

Fodinisporobacter ferrooxydans gen. nov., sp. nov.-A Spore-Forming Ferrous-Oxidizing Bacterium Isolated from a Polymetallic Mine

A novel acidophilic, aerobic bacterium strain, MYW30-H2T, was isolated from a heap of polymetallic mine. Cells of strain MYW30-H2T were Gram-stain-positive, endospore-forming, motile, and rod-shaped. Strain MYW30-H2T grew at a temperature range of 30-45 °C (optimum 40 °C) and a pH range of 3.5-6.0 (optimum 4.0) in the presence of 0-0.5% (w/v) NaCl. Strain MYW30-H2T could grow heterotrophically on yeast extract and glucose, and grow mixotrophically using ferrous iron as an electron donor with yeast extract. Menaquinone-7 (MK-7) was the sole respiratory quinone of the strain. Iso-C15:0 and anteiso-C15:0 were the major cellular fatty acids. The 16S rRNA gene sequence analysis showed that MYW30-H2T was phylogenetically affiliated with the family Alicyclobacillaceae, and the sequence similarity with other Alicyclobacillaceae genera species was below 91.51%. The average amino acid identity value of the strain with its phylogenetically related species was 52.3-62.1%, which fell into the genus boundary range. The DNA G+C content of the strain was 44.2%. Based on physiological and phylogenetic analyses, strain MYW30-H2T represents a novel species of a new genus of the family Alicyclobacillaceae, for which the name Fodinisporobacter ferrooxydans gen. nov., sp. nov. is proposed. The type strain is MYW30-H2T (=CGMCC 1.17422T = KCTC 43278T).

Effects of poly(3-hydroxybutyrate) [P(3HB)] coating on the bacterial communities of artificial structures

The expanding urbanization of coastal areas has led to increased ocean sprawl, which has had both physical and chemical adverse effects on marine and coastal ecosystems. To maintain the health and functionality of these ecosystems, it is imperative to develop effective solutions. One such solution involves the use of biodegradable polymers as bioactive coatings to enhance the bioreceptivity of marine and coastal infrastructures. Our study aimed to explore two main objectives: (1) investigate PHA-degrading bacteria on polymer-coated surfaces and in surrounding seawater, and (2) comparing biofilm colonization between surfaces with and without the polymer coating. We applied poly(3-hydroxybutyrate) [P(3HB)) coatings on concrete surfaces at concentrations of 1% and 6% w/v, with varying numbers of coating cycles (1, 3, and 6). Our findings revealed that the addition of P(3HB) indeed promoted accelerated biofilm growth on the coated surfaces, resulting in an occupied area approximately 50% to 100% larger than that observed in the negative control. This indicates a remarkable enhancement, with the biofilm expanding at a rate roughly 1.5 to 2 times faster than the untreated surfaces. We observed noteworthy distinctions in biofilm growth patterns based on varying concentration and number of coating cycles. Interestingly, treatments with low concentration and high coating cycles exhibited comparable biofilm enhancements to those with high concentrations and low coating cycles. Further investigation into the bacterial communities responsible for the degradation of P(3HB) coatings identified mostly common and widespread strains but found no relation between the concentration and coating cycles. Nevertheless, this microbial degradation process was found to be highly efficient, manifesting noticeable effects within a single month. While these initial findings are promising, it's essential to conduct tests under natural conditions to validate the applicability of this approach. Nonetheless, our study represents a novel and bio-based ecological engineering strategy for enhancing the bioreceptivity of marine and coastal structures.

Exploration of culturable bacterial associates of aphids and their interactions with entomopathogens

Aphids shelter several bacteria that benefit them in various ways. The associates having an obligatory relationship are non-culturable, while a few of facultative associates are culturable in insect cell lines, axenic media or standard microbiology media. In the present investigation, isolation, and characterization of the culturable bacterial associates of various aphid species, viz., Rhopalosiphum maidis, Rhopalosiphum padi, Sitobion avenae, Schizaphis graminum, and Lipaphis erysimi pseudobrassicae were carried out. A total of 42 isolates were isolated using different growth media, followed by their morphological, biochemical, and molecular characterization. The isolated culturable bacterial associates were found to belong to the genera Acinetobacter, Bacillus, Brevundimonas, Cytobacillus, Fictibacillus, Planococcus, Priestia, Pseudomonas, Staphylococcus, Sutcliffiella, and Tumebacillus which were grouped under seven families of four different orders of phyla Bacillota (Firmicutes) and Pseudomonata (Proteobacteria). Symbiont-entomopathogen interaction study was also conducted, in which the quantification of colony forming units of culturable bacterial associates of entomopathogenic fungal-treated aphids led us to the assumption that the bacterial load in aphid body can be altered by the application of entomopathogens. Whereas, the mycelial growth of entomopathogens Akanthomyces lecanii and Metarhizium anisopliae was found uninhibited by the bacterial associates obtained from Sitobion avenae and Rhopalosiphum padi. Analyzing persistent aphid microflora and their interactions with entomopathogens enhances our understanding of aphid resistance. It also fosters the development of innovative solutions for agricultural pest management, highlighting the intricate dynamics of symbiotic relationships in pest management strategies.

Tumebacillus lacus sp. nov., isolated from lake water

A Gram-stain-positive, aerobic, rod-shaped, endospore-forming and motile, by means of peritrichous flagella, bacterium, designated DT12T, was isolated from a lake water sample from Datun Lake of Yunnan Province, PR China. The results of phylogenetic analysis based on 16S rRNA gene sequence and the concatenated alignment of 120 ubiquitous single-copy proteins indicated that the novel strain represented a member of the genus Tumebacillus. The sole quinone was menaquinone-7 and the cell-wall peptidoglycan was type-A1γ. The major fatty acids (>10 %) of the novel strain were iso-C15 : 0 and anteiso-C15 : 0, while the major polar lipids were phosphatidylmonomethylethanolamine, phosphatidylethanolamine and phosphatidylglycerol. The results of phylogenetic analyses combined with phylogenetic, phenotypic and chemotaxonomic features, strongly supported the hypothesis that the strain should be classified as representing a novel species of the genus Tumebacillus, for which the name Tumebacillus lacus sp. nov. is proposed. The type strain is DT12T (=KCTC 33958T= MCCC 1H00320T). The genomic analysis revealed that DT12T has various biosynthetic gene clusters for secondary metabolites, and members of the genus Tumebacillus may represent a promising source of new natural products. Our study also showed that members of the genus Tumebacillus are widely distributed in a variety of habitats throughout the globe, particularly in soils, human-, animal- and plant-associated environments. Members of the genus Tumebacillus may have an important role in the growth and health of humans, plants and animals.

Chryseobacterium edaphi sp. nov. and Chryseobacterium gilvum sp. nov., isolated from soil

Two Gram-stain-negative, aerobic, yellow and rod-shaped bacteria, designated as strains PBS4-4^T and GMJ5^T, were isolated from soil samples collected in Goyang-si and Paju-si, Gyeonggi-do, Republic of Korea. Strains PBS4-4^T and GMJ5^T were both positive for catalase and oxidase. Strain PBS4-4^T grew at 15-37 °C and pH 5.0-12.0. Strain GMJ5^T grew at 15-37 °C and pH 5.0-11.0. Neither strain required NaCl for growth. 16S rRNA sequence analysis revealed that strains PBS4-4^T and GMJ5^T form a closely related cluster with the genus Chryseobacterium. The average nucleotide identity and digital DNA-DNA hybridization values between strain PBS4-4^T and its closely related strains were 79.4-84.5% and 23.2-28.7 %, respectively. For GMJ5^T, the values were 78.3-79.3% and 22.0-22.6 %, respectively. The major fatty acids shared by both novel strains were iso-C_15 : 0 and summed feature 3 (C_16 : 1 ω7c/C_16 : 1 ω6c). Strain GMJ5^T had one other major fatty acid: iso-C_17 : 0 3OH. Based on phenotypic, genomic and phylogenetic results, strains PBS4-4^T and GMJ5^T represent novel species within the genus Chryseobacterium, and the names Chryseobacterium edaphi sp. nov. and Chryseobacterium gilvum sp. nov. are proposed, respectively. The type strain of C. edaphi is PBS4-4^T (=KACC 22882^T=TBRC 17052^T) and the type strain of C. gilvum is GMJ5^T (=KACC 22883^T=TBRC 17053^T).

Comprehensive analysis of biosynthetic gene clusters in bacteria and discovery of Tumebacillus as a potential producer of natural products

Limited microbial genera such as Streptomyces have served as sources of natural products (NPs), whereas most others have been less investigated. The vast accumulation of genomic data available in the NCBI database enables us to bioinformatically estimate the ability of other microbial groups to produce NPs. We analyzed 21,052 complete bacterial genome sequences using antiSMASH and compared the average numbers of biosynthetic gene clusters (BGCs) related to polyketides, non-ribosomal peptides, and/or terpenes biosynthesis at the genus level. Our bioinformatic analyses showed that Tumebacillus has 5-15 BGCs and is a promising NP producer. We searched for NPs from the culture broth of Tumebacillus permanentifrigoris JCM 14557^T and found two novel compounds (tumebacin with anti-Bacillus activity and tumepyrazine) and identified two known compounds. Our results highlight the diversity of sources of NPs awaiting discovery.