Polysaccharide degradation in Cellvibrionaceae: Genomic insights of the novel chitin-degrading marine bacterium, strain KSP-S5-2, and its chitinolytic activity.

In this study, we present the genome characterization of a novel chitin-degrading strain, KSP-S5-2, and comparative genomics of 33 strains of Cellvibrionaceae. Strain KSP-S5-2 was isolated from mangrove sediment collected in Balik Pulau, Penang, Malaysia, and its 16S rRNA gene sequence showed the highest similarity (95.09%) to Teredinibacter franksiae. Genome-wide analyses including 16S rRNA gene sequence similarity, average nucleotide identity, digital DNA-DNA hybridization, and phylogenomics, suggested that KSP-S5-2 represents a novel species in the family Cellvibrionaceae. The Cellvibrionaceae pan-genome exhibited high genomic variability, with only 1.7% representing the core genome, while the flexible genome showed a notable enrichment of genes related to carbohydrate metabolism and transport pathway. This observation sheds light on the genetic plasticity of the Cellvibrionaceae family and the gene pools that form the basis for the evolution of polysaccharide-degrading capabilities. Comparative analysis of the carbohydrate-active enzymes across Cellvibrionaceae strains revealed that the chitinolytic system is not universally present within the family, as only 18 of the 33 genomes encoded chitinases. Strain KSP-S5-2 displayed an expanded repertoire of chitinolytic enzymes (25 GH18, two GH19 chitinases, and five GH20 ß-N-acetylhexosaminidases) but lacked genes for agar, xylan, and pectin degradation, indicating specialized enzymatic machinery focused primarily on chitin degradation. Further, the strain degraded 90% of chitin after 10 days of incubation. In summary, our findings provided insights into strain KSP-S5-2's genomic potential, the genetics of its chitinolytic system, genomic diversity within the Cellvibrionaceae family in terms of polysaccharide degradation, and its application for chitin degradation.

A metagenomic comparison of clearwater, probiotic, and Rapid BFTTM on Pacific whiteleg shrimp, Litopenaeus vannamei cultures.

Biofloc technology improves water quality and promote the growth of beneficial bacteria community in shrimp culture. However, little is known about the bacteria community structure in both water and gut of cultured organisms. To address this, the current study characterised the metagenomes derived from water and shrimp intestine samples of novel Rapid BFTTM with probiotic and clearwater treatments using 16S V4 region and full length 16S sequencing. Bacteria diversity of water and intestine samples of Rapid BFTTM and probiotic treatments were similar. Based on the 16S V4 region, water samples of >20 µm biofloc had the highest abundance of amplicon sequence variant (ASV). However, based on full length 16S, no clear distinction in microbial diversity was observed between water samples and intestine samples. Proteobacteria was the most abundant taxon in all samples based on both 16S V4 and full length 16S sequences. Vibrio was among the highest genus based on 16S V4 region but only full length 16S was able to discern up to species level, with three Vibrios identified-V. harveyi, V. parahaemolyticus and V. vulnificus. Vibrio harveyi being the most abundant species in all treatments. Among water samples, biofloc water samples had the lowest abundance of all three Vibrios, with V. vulnificus was present only in bioflocs of <20 µm. Predicted functional profiles of treatments support the beneficial impacts of probiotic and biofloc inclusion into shrimp culture system. This study highlights the potential displacement of opportunistic pathogens by the usage of biofloc technology (Rapid BFTTM) in shrimp culture.

Complete genome sequence of marine filamentous bacterium, Saprospira grandis strain WHT.

Here, we report the complete genome sequence of a type strain of the genus Saprospira, Saprospira grandis strain WHT. The genome consists of one circular chromosome and plasmid comprising 4,250,550 bp and 53,161 bp with GC content of 46.6% and 46.8%, respectively.

16S rRNA Gene Amplicon Sequencing Data for Pteris vittata Rhizosphere Soils.

Data on the 16S rRNA gene amplicon sequences from Pteris vittata rhizosphere soils are reported. The following phyla were recorded in arsenic-rich soils: Actinobacteria (59%), Proteobacteria (26%), Chloroflexi (17%), and Acidobacteria (9%). Actinobacteria (45%), Proteobacteria (22%), Chloroflexi (10%), and Acidobacteria (11%) were in natural-mineral soils.

Genome Sequence of Vibrio sp. Strain CCB-PB317, Isolated from a Malaysian Mangrove, and Its Arsenic Resistance Mechanisms.

Vibrio sp. strain CCB-PB317 with potential arsenic detoxification was isolated from a mangrove in Pulau Betong, Malaysia. Here, we report a draft genome sequence of strain CCB-PB317, which comprised 5,157,574 bp with a G+C content of 44.9%. The genome contains genes related to an arsenic resistance system coupled with glycolytic metabolism.

Comparative Analyses of Scylla olivacea Gut Microbiota Composition and Function Suggest the Capacity for Polyunsaturated Fatty Acid Biosynthesis.

Although numerous studies in aquatic organisms have linked lipid metabolism with intestinal bacterial structure, the possibility of the gut microbiota participating in the biosynthesis of beneficial long-chain polyunsaturated fatty acid (LC-PUFA) remains vague. We profiled the gut microbiota of the mud crab Scylla olivacea fed with either a LC-PUFA rich (FO) or a LC-PUFA-poor but C18-PUFA substrate-rich (LOCO) diet. Additionally, a diet with a similar profile as LOCO but with the inclusion of an antibiotic, oxolinic acid (LOCOAB), was also used to further demarcate the possibility of LC-PUFA biosynthesis in gut microbiota. Compared to diet FO treatment, crabs fed diet LOCO contained a higher proportion of Proteobacteria, notably two known taxonomy groups with PUFA biosynthesis capacity, Vibrio and Shewanella. Annotation of metagenomic datasets also revealed enrichment in the KEGG pathway of unsaturated fatty acid biosynthesis and polyketide synthase-like system sequences with this diet. Intriguingly, diet LOCOAB impeded the presence of Vibrio and Shewanella and with it, the function of unsaturated fatty acid biosynthesis. However, there was an increase in the function of short-chain fatty acid production, accompanied by a shift towards the abundance of phyla Bacteroidota and Spirochaetota. Collectively, these results exemplified bacterial communities and their corresponding PUFA biosynthesis pathways in the microbiota of an aquatic crustacean species.

Transcriptomic Signature of Horseshoe Crab Carcinoscorpius rotundicauda Hemocytes' Response to Lipopolysaccharides.

Carcinoscorpius rotundicauda (C. rotundicauda) is one of the four species of horseshoe crabs (HSCs). The HSC hemocytes store defense molecules that are released upon encountering invading pathogens. The HSCs rely on this innate immunity to continue its existence as a living fossil for more than 480 million years. To gain insight into the innate mechanisms involved, transcriptomic analysis was performed on isolated C. rotundicauda hemocytes challenged with lipopolysaccharides (LPS), the main components of the outer cell membrane of gram-negative bacteria. RNA-sequencing with Illumina HiSeq platform resulted in 232,628,086 and 245,448,176 raw reads corresponding to 190,326,253 and 201,180,020 high-quality mappable reads from control and LPS-stimulated hemocytes, respectively. Following LPS-stimulation, 79 genes were significantly upregulated and 265 genes were downregulated. The differentially expressed genes (DEGs) were related to multiple immune functional categories and pathways such as those of the cytoskeleton, Toll and Imd, apoptosis, MAP kinase (MAPK), inositol phosphate metabolism, phagosome, leucocyte endothelial migration, and gram-negative bacterial infection, among others. This study provides important information about the mechanisms of response to LPS, which is relevant for the understanding the HSCs' immune response.

Genome sequence data of Bacillus sp. CCB-MMP212 isolated from Malaysian mangrove: A potential strain in arsenic resistance with ArsI, C•As lyase.

Bacillus sp. CCB-MMP212 is a Gram-positive bacterium isolated from mangrove sediment in Matang Perak, Malaysia (4.85496°E, 100.73495°N). Genome sequencing was performed using the Oxford Nanopore and Illumina platforms. The assembled genome was annotated using the rapid annotation subsystem technology server (RAST) (rast.nmpdr.org). The genome size of the Bacillus sp. CCB-MMP212 was 6,151,644 base pairs (bp) with a G+C content of 34.75%. The genome includes 6,311 coding sequences and 58 RNAs. The sequence has been deposited at Genbank with the accession number of JALDQE000000000. Interestingly, an arsenic resistance (ars) operon consisted of arsenic resistance operon repressor (arsR), ACR3 family arsenite efflux transporter (arsB), and arsenate reductase (arsC) genes were found in the genome. In addition, the arsenic inducible gene (arsI), which encoded a dioxygenase with C•As lyase activity, was also found in the ars operon. The enzyme is crucial for the methylation of methylarsonous acid [MAs(III)] and trivalent roxarsone [Rox(III)]. This dataset reveals the genetic ability of this strain in arsenic resistance. To the best of our knowledge, the arsI encoding C•As lyase is rarely reported within the genus Bacillus. Therefore, the dataset presented in this manuscript provides further insight into the arsenic resistance mechanisms of the genus Bacillus.

Comparative Genomic Analyses of the Genus Photobacterium Illuminate Biosynthetic Gene Clusters Associated with Antagonism.

The genus Photobacterium is known for its ecophysiological versatility encompassing free-living, symbiotic, and pathogenic lifestyles. Photobacterium sp. CCB-ST2H9 was isolated from estuarine sediment collected at Matang Mangrove, Malaysia. In this study, the genome of CCB-ST2H9 was sequenced, and the pan-genome of 37 Photobacterium strains was analysed. Phylogeny based on core genes showed that CCB-ST2H9 clustered with P. galatheae, forming a distinct clade with P. halotolerans, P. salinisoli, and P. arenosum. The core genome of Photobacterium was conserved in housekeeping functions, while the flexible genome was well represented by environmental genes related to energy production and carbohydrate metabolism. Genomic metrics including 16S rRNA sequence similarity, average nucleotide identity, and digital DNA-DNA hybridization values were below the cut-off for species delineation, implying that CCB-ST2H9 potentially represents a new species. Genome mining revealed that biosynthetic gene clusters (BGCs) involved in producing antimicrobial compounds such as holomycin in CCB-ST2H9 could contribute to the antagonistic potential. Furthermore, the EtOAc extract from the culture broth of CCB-ST2H9 exhibited antagonistic activity against Vibrio spp. Intriguingly, clustering based on BGCs profiles grouped P. galatheae, P. halotolerans, P. salinisoli, P. arenosum, and CCB-ST2H9 together in the heatmap by the presence of a large number of BGCs. These BGCs-rich Photobacterium strains represent great potential for bioactive secondary metabolites production and sources for novel compounds.

A complete inventory of long-chain polyunsaturated fatty acid biosynthesis pathway enzymes in the miniaturized cyprinid Paedocypris micromegethes.

The capacity for long-chain polyunsaturated fatty acid (LC-PUFA) biosynthesis activity in a species depends on the enzymatic activities of fatty acyl desaturase (Fads) and elongation of very long-chain fatty acid (Elovl). The miniaturized fish Paedocypris micromegethes is a developmentally truncated cyprinid living in highly acidic water conditions in tropical peat swamps. The capacity for LC-PUFA biosynthesis in this species, which has a reduced genome size, is unknown. A high-quality de novo transcriptome assembly enabled the identification of a putative Fads2 and four Elovl. The Fads2 was verified as a P. micromegethes Fads2 ortholog with in vitro Δ5 and Δ6 activities. The Elovl sequences were established as an Elovl5, Elovl2, and two Elovl4 paralogs, namely Elovl4a and Elovl4b. These Elovl enzymes, mainly Elovl5 and Elovl2, fulfill the necessary C18, C20, and C22 PUFA elongation steps for LC-PUFA biosynthesis. Collectively, these results validate the presence of a complete repertoire of LC-PUFA biosynthesis enzymes in a peat swamp miniatured freshwater fish.

Long-chain polyunsaturated fatty acid biosynthesis in a land-crab with advanced terrestrial adaptations: Molecular cloning and functional characterization of two fatty acyl elongases.

Depending on the presence and activities of the front-end fatty acyl desaturases and elongation of very long-chain fatty acid (Elovl) enzymes, animals have different capacities for long-chain (≥C20) polyunsaturated fatty acids (LC-PUFA) biosynthesis. Successful land colonisation in brachyuran crabs requires a shift towards terrestrial food chain with limited LC-PUFA availability. We cloned and functionally characterised two elovl genes from the purple land crab Gecarcoidea lalandii. The two Elovl contained all the necessary motifs of a typical polyunsaturated fatty acids (PUFA) Elovl and phylogenetically clustered in the Elovl1 and Elovl6 clades, respectively. The G. lalandii Elovl1 elongated saturated fatty acids, with low activities towards C20 and C22 PUFA substrates. Moreover, the G. lalandii Elovl6 was particularly active in the elongation of C18 PUFA, although it also recognised monounsaturated fatty acids as substrates for elongation. Collectively, the herein characterised G. lalandii elovl paralogues fulfil all the elongation steps involved in the LC-PUFA biosynthetic pathways. Tissue distribution of the G. lalandii elovl genes, along with the FA composition analyses, suggest the hepatopancreas and gill as key metabolic sites for fatty acid elongation. However, current data suggest that G. lalandii is unable to rely solely on biosynthesis to fulfil LC-PUFA requirements, since front-end desaturase appears to be absent in this species and other decapods.

Metabolic strategies of dormancy of a marine bacterium Microbulbifer aggregans CCB-MM1: Its alternative electron transfer chain and sulfate-reducing pathway.

Bacterial dormancy plays a crucial role in maintaining the functioning and diversity of microbial communities in natural environments. However, the metabolic regulations of the dormancy of bacteria in natural habitats, especially marine habitats, have remained largely unknown. A marine bacterium, Microbulbifer aggregans CCB-MM1 exhibits rod-to-coccus cell shape change during the dormant state. Therefore, to clarify the metabolic regulation of the dormancy, differential gene expression analysis based on RNA-Seq was performed between rod- (vegetative), intermediate, and coccus-shaped cells (dormancy). The RNA-Seq data revealed that one of two distinct electron transfer chains was upregulated in the dormancy. Dissimilatory sulfite reductase and soluble hydrogenase were also highly upregulated in the dormancy. In addition, induction of the dormancy of MM1 in the absence of MgSO4 was slower than that in the presence of MgSO4. These results indicate that the sulfate-reducing pathway plays an important role in entering the dormancy of MM1.

Saccharobesus litoralis gen. nov., sp. nov., a novel alginate-degrading bacterium isolated from the surface of intertidal algal turf.

A novel rod-shaped, Gram-stain-negative, strictly aerobic and alginate-degrading marine bacterium, designated CCB-QB4T, was isolated from a surface of algal turf collected from a coastal area of Penang, Malaysia. The cells showed motility by a lateral flagellum. The rod-shaped cells formed long chains end-to-end. Phylogenetic analysis based on the 16S rRNA gene sequence of strain CCB-QB4T showed 94.07, 92.69, 91.52 and 90.90 % sequence similarity to Algibacillus agarilyticus RQJ05T, Catenovulum maritimum Q1T, Catenovulum agarivorans YM01T and Catenovulum sediminis D2T, respectively. Strain CCB-QB4T formed a cluster with A. agarilyticus RQJ05T. Strain CCB-QB4T was catalase-negative, oxidase-positive, and degraded agar, alginate, and starch. Cell growth was observed at 15-40 °C, at pH 7.0-10.0 and in the presence of 1-6 % (w/v) NaCl and glucose. The major fatty acids were summed feature 3 (C16 : 1 ω7c/iso-C15 : 0 2-OH), C16 : 0 and C18 : 1 ω7c. The polar lipids were phosphatidylethanolamine, two unidentified aminolipids, two unidentified glycolipids, an unidentified phospholipid and unidentified lipid. The major respiratory quinone was ubiquinone-8. The genomic DNA G+C content was 46.7 mol%. Based on the phenotypic, chemotaxonomic and phylogenetic data, strain CCB-BQ4T represents a novel species in a new genus, for which the name Saccharobesus litoralis gen. nov., sp. nov. is proposed. The type strain is CCB-QB4T (=JCM 33513T=CCB-MBL 5008T).

Comparative transcriptome profiling of horseshoe crab Tachypleus gigas hemocytes in response to lipopolysaccharides.

Horseshoe crabs (HSCs) are living fossil species of marine arthropods with a long evolutionary history spanning approximately 500 million years. Their survival is helped by their innate immune system that comprises cellular and humoral immune components to protect them against invading pathogens. To help understand the genetic mechanisms involved, the present study utilised the Illumina HiSeq platform to perform transcriptomic analysis of hemocytes from the HSC, Tachypleus gigas, that were challenged with lipopolysaccharides (LPS). The high-throughput sequencing resulted in 352,077,208 and 386,749,136 raw reads corresponding to 282,490,910 and 305,709,830 high-quality mappable reads for the control and LPS-treated hemocyte samples, respectively. Based on the log-fold change of > 0.3 or < -0.3, 1338 genes were significantly upregulated and 215 genes were significantly downregulated following LPS stimulation. The differentially expressed genes (DEGs) were further identified to be associated with multiple pathways such as those related to immune defence, stress response, cytoskeleton function and signal transduction. This study provides insights into the underlying molecular and regulatory mechanisms in hemocytes exposed to LPS, which has relevance for the study of the immune response of HSCs to infection.

Mitochondrial DNA sequence of the horseshoe crab Tachypleus gigas.

This paper reports on the complete mitochondrial (mt) genome of a horseshoe crab, Tachypleus gigas (T. gigas), in Kuala Kemaman, Terengganu, Malaysia. Whole-genome sequencing of hemocyte DNA was performed with Illumina HiSeq system and the generated reads were de novo assembled with ABySS 2.1.5 and reassembled using mitoZ against Carcinoscorpius rotundicauda and Limulus polyphemus, resulting in a contig of 15 Kb. Phylogenetic analysis of the assembled mt genome suggests that the Tachypleus gigas is closely related to Tachypleus tridentatus than to Carcinoscorpius rotundicauda.

Metagenomic data on bacterial diversity profiling of high-microbial-abundance tropical marine sponges Aaptos aaptos and Xestospongia muta from waters off terengganu, South China Sea.

Marine sponges are acknowledged as a bacterial hotspot and resource of novel natural products or genetic material with industrial or commercial potential. However, sponge-associated bacteria are difficult to be cultivated and the production of their desirable metabolites is inadequate in terms of rate and quantity, yet bioinformatics and metagenomics tools are steadily progressing. Bacterial diversity profiles of high-microbial-abundance wild tropical marine sponges Aaptos aaptos and Xestospongia muta were obtained by sample collection at Pulau Bidong and Pulau Redang islands, 16S rRNA amplicon sequencing on Illumina HiSeq2500 platform (250 bp paired-end) and metagenomics analysis using Ribosomal Database Project (RDP) classifier. Raw sequencing data in fastq format and relative abundance histograms of the dominant 10 species are available in the public repository Discover Mendeley Data (http://dx.doi.org/10.17632/zrcks5s8xp). Filtered sequencing data of operational taxonomic unit (OTU) with chimera removed is available in NCBI accession numbers from MT464469 to MT465036.

Functional characterisation of fatty acyl desaturase, Fads2, and elongase, Elovl5, in the Boddart's goggle-eyed goby Boleophthalmus boddarti (Gobiidae) suggests an incapacity for long-chain polyunsaturated fatty acid biosynthesis.

The biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFA), a process to convert C18 polyunsaturated fatty acids into eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) or arachidonic acid (ARA), requires the concerted activities of two enzymes, the fatty acyl desaturase (Fads) and elongase (Elovl). This study highlights the cloning, functional characterisation and tissue expression pattern of a Fads and an Elovl from the Boddart's goggle-eyed goby (Boleophthalmus boddarti), a mudskipper species widely distributed in the Indo-Pacific region. Phylogenetic analysis revealed that the cloned fads and elovl are clustered with other teleost orthologs, respectively. The investigation of the genome of several mudskipper species, namely Boleophthalmus pectinirostris, Periophthalmus schlosseri and Periophthalmus magnuspinnatus, revealed a single Fads2 and two elongases, Elovl5 and Elovl4 for each respective species. A heterologous yeast assay indicated that the B. boddarti Fads2 possessed low desaturation activity on C18 PUFA and no desaturation on C20 and C22 PUFA substrates. In comparison, the Elovl5 showed a wide range of substrate specificity, with a capacity to elongate C18, C20 and C22 PUFA substrates. An amino acid residue that affects the capacity to elongate C22:5n-3 was identified in the B. boddarti Elovl5. Both genes are highly expressed in brain tissue. Among all tissues, DHA is highly concentrated in neuron-rich tissues, whereas EPA is highly deposited in gills. Taken together, the results showed that due to the inability to perform desaturation steps, B. boddarti is unable to biosynthesise LC-PUFA, relying on dietary intake to acquire these nutrients.

Draft Genome Sequence of the Halophilic Pararhodobacter-Like Strain CCB-MM2, Which Has Polyhydroxyalkanoate-Synthesizing Potential.

Pararhodobacter-like strain CCB-MM2 is a halophilic alphaproteobacterium isolated from estuarine sediment collected from Matang Mangrove Forest in Malaysia. Here, we present the draft genome sequence of CCB-MM2 and provide insights into its physiological roles and metabolic potential.

Genomic analysis of methicillin-resistant Staphylococcus aureus strain SO-1977 from Sudan.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is known as a leading cause of morbidity and mortality. Investigation of the MRSA's virulence and resistance mechanisms is a continuing concern toward controlling such burdens through using high throughput whole Genome Sequencing (WGS) and molecular diagnostic assays. The objective of the present study is to perform whole-genome sequencing of MRSA isolated from Sudan using Illumina Next Generation Sequencing (NGS) platform. RESULTS: The genome of MRSA strain SO-1977 consists of 2,827,644 bp with 32.8% G + C, 59 RNAs and 2629 predicted coding sequences (CDSs). The genome has 26 systems, one of which is the major class in the disease virulence and defence. A total of 83 genes were annotated to virulence disease and defence category some of these genes coding as functional proteins. Based on genome analysis, it is speculated that the SO-1977 strain has resistant genes to Teicoplanin, Fluoroquinolones, Quinolone, Cephamycins, Tetracycline, Acriflavin and Carbapenems. The results revealed that the SO-1977, strain isolated from Sudan has a wide range of antibiotic resistance compared to related strains. CONCLUSION: The study reports for the first time the whole genome sequence of Sudan MRSA isolates. The release of the genome sequence of the strain SO-1977 will avail MRSA in public databases for further investigations on the evolution of resistant mechanism and dissemination of the -resistant genes of MRSA.