@article {8318, title = {High-quality single amplicon sequencing method for illumina MiSeq platform using pool of {\textquoteright}N{\textquoteright} (0-10) spacer-linked target specific primers without PhiX spike-in [Next Gen Genomics Facility (INT)]}, journal = {BMC Genomics}, volume = {24}, year = {2023}, month = {2023 Mar 23}, pages = {141}, abstract = {

BACKGROUND: Illumina sequencing platform requires base diversity in the initial 11 cycles for efficient cluster identification and colour matrix estimation. This limitation yields low-quality data for amplicon libraries having homogeneous base composition. Spike-in of PhiX library ensures base diversity but reduces the overall number of sequencing reads for data analysis. To overcome such low diversity issues during amplicon sequencing on illumina platforms, we developed a high throughput single amplicon sequencing method by introducing {\textquoteright}N{\textquoteright} (0-10) spacers in target gene amplification primers that are pooled for simple handling.

RESULT: We evaluated the efficiency of {\textquoteright}N{\textquoteright} (0-10) spacer-linked primers by targeting bacterial 16S V3-V4 region, demonstrating heterogeneous base library construction. The addition of {\textquoteright}N{\textquoteright} (0-10) spacers causes sequencing frameshift at every base that leads to base diversity and produces heterogeneous high quality reads within a single amplicon library. We have written a python based command-line software,"MetReTrim", to trim the {\textquoteright}N{\textquoteright} (0-10) spacers from the raw reads ( https://github.com/Mohak91/MetReTrim ). We further demonstrated the accuracy of this method by comparative mock community analysis with standard illumina V3-V4 primer method. The ZymoBIOMICS{\texttrademark} microbial community DNA standard was used as a control for this study. We performed data analysisusing the DADA2 pipeline where taxonomy was assigned using SILVA database as reference. We observed no difference between the communities represented by our method and standard illumina V3-V4 primer method.

CONCLUSION: This method eliminates the need for PhiX spike-in for single amplicon sequencing on illumina MiSeq platform. This allows for sequencing of more number of samples in a run and a reduction in the overall cost. Given that Illumina sequencing works on SBS chemistry irrespective of the platform (such as HiSeq, MiSeq, NextSeq, NovaSeq, etc.) we propose that this strategy of using {\textquoteright}N{\textquoteright} (0-10) spacer-linked primer design can be adopted for generating high-quality single locus amplicon sequencing in a high throughput manner across the illumina platform subject to further validation.

}, keywords = {Bacteria, Gene Library, High-Throughput Nucleotide Sequencing, Microbiota, RNA, Ribosomal, 16S, Sequence Analysis, DNA}, issn = {1471-2164}, doi = {10.1186/s12864-023-09233-4}, author = {Naik, Tejali and Sharda, Mohak and C P, Lakshminarayanan and Virbhadra, Kumar and Pandit, Awadhesh} } @article {8356, title = {Lunatimonas lonarensis gen. nov., sp. nov., a haloalkaline bacterium of the family Cyclobacteriaceae with nitrate reducing activity [Next Gen Genomics Facility]}, journal = {Syst Appl Microbiol}, volume = {37}, year = {2014}, month = {2014 Feb}, pages = {10-6}, abstract = {

Novel pinkish-orange pigmented, Gram-negative staining, half-moon shaped, non-motile, strictly aerobic strains designated AK24(T) and AK26 were isolated from water and sediment samples of Lonar Lake, Buldhana district, Maharahstra, India. Both strains were positive for oxidase, catalase and β-galactosidase activities. The predominant fatty acids were iso-C15:0 (41.5\%), anteiso-C15:0 (9.7\%), iso-C17:0 3OH (9.6\%), iso-C17:1 ω9c (10.2\%) and C16:1 ω7c/C16:1 ω6c/iso-C15:0 2OH (summed feature 3) (14.4\%). The strains contained MK-7 as the major respiratory quinone, and phosphatidylethanolamine and five unidentified lipids as the polar lipids. Blast analysis of the 16S rRNA gene sequence of strain AK24(T) showed that it was closely related to Aquiflexum balticum, with a pair-wise sequence similarity of 91.6\%, as well as to Fontibacter ferrireducens, Belliella baltica and Indibacter alkaliphilus (91.3, 91.2 and 91.2\% pair-wise sequence similarity, respectively), but it only had between 88.6 and 91.0\% pair-wise sequence similarity to the rest of the family members. The MALDI-TOF assay reported no significant similarities for AK24(T) and AK26, since they potentially represented a new species. A MALDI MSP dendrogram showed close similarity between the two strains, but they maintained a distance from their phylogenetic neighbors. The genome of AK24(T) showed the presence of heavy metal tolerance genes, including the genes providing resistance to arsenic, cadmium, cobalt and zinc. A cluster of heat shock resistance genes was also found in the genome. Two lantibiotic producing genes, LanR and LasB, were also found in the genome of AK24(T). Strains AK24(T) and AK26 were very closely related to each other with 99.5\% pair-wise sequence similarity. Phylogenetic analysis indicated that the strains were members of the family Cyclobacteriaceae and they clustered with the genus Mariniradius, as well as with the genera Aquiflexum, Cecembia, Fontibacter, Indibacter, and Shivajiella. DNA-DNA hybridization between strains AK24(T) and AK26 showed a relatedness of 82\% and their rep-PCR banding patterns were very similar. Based on data from the current polyphasic study, it is proposed that the isolates be placed in a new genus and species with the name Lunatimonas lonarensis gen. nov., sp. nov. The type strain of Lunatimonas lonarensis is AK24(T) (=JCM 18822(T)=MTCC 11627(T)).

}, keywords = {Bacterial Typing Techniques, Bacteroidetes, Cluster Analysis, DNA, Bacterial, DNA, Ribosomal, Fatty Acids, Fresh Water, Genome, Bacterial, Geologic Sediments, India, Molecular Sequence Data, Nitrates, Oxidation-Reduction, Phospholipids, Phylogeny, Quinones, RNA, Ribosomal, 16S, Sequence Analysis, DNA}, issn = {1618-0984}, doi = {10.1016/j.syapm.2013.10.003}, author = {Srinivas, T N R and Aditya, S and Bhumika, V and Kumar, P Anil} } @article {488, title = {Genome sequencing unveils a novel sea enterotoxin-carrying PVL phage in Staphylococcus aureus ST772 from India. [Next Generation Genomics facility]}, journal = {PLoS One}, volume = {8}, year = {2013}, month = {2013}, pages = {e60013}, abstract = {

Staphylococcus aureus is a major human pathogen, first recognized as a leading cause of hospital-acquired infections. Community-associated S. aureus (CA-SA) pose a greater threat due to increase in severity of infection and disease among children and healthy adults. CA-SA strains in India are genetically diverse, among which is the sequence type (ST) 772, which has now spread to Australia, Europe and Japan. Towards understanding the genetic characteristics of ST772, we obtained draft genome sequences of five relevant clinical isolates and studied the properties of their PVL-carrying prophages, whose presence is a defining hallmark of CA-SA. We show that this is a novel prophage, which carries the structural genes of the hlb-carrying prophage and includes the sea enterotoxin. This architecture probably emerged early within the ST772 lineage, at least in India. The sea gene, unique to ST772 PVL, despite having promoter sequence characteristics typical of low expression, appears to be highly expressed during early phase of growth in laboratory conditions. We speculate that this might be a consequence of its novel sequence context. The crippled nature of the hlb-converting prophage in ST772 suggests that widespread mobility of the sea enterotoxin might be a selective force behind its {\textquoteright}transfer{\textquoteright} to the PVL prophage. Wild type ST772 strains induced strong proliferative responses as well as high cytotoxic activity against neutrophils, likely mediated by superantigen SEA and the PVL toxin respectively. Both proliferation and cytotoxicity were markedly reduced in a cured ST772 strain indicating the impact of the phage on virulence. The presence of SEA alongside the genes for the immune system-modulating PVL toxin may contribute to the success and virulence of ST772.

}, keywords = {Bacterial Toxins, Base Sequence, Enterotoxins, Exotoxins, Genome, Bacterial, Hemolysin Proteins, Humans, India, Leukocidins, Molecular Sequence Data, Prophages, RNA, Messenger, Sequence Analysis, DNA, Sphingomyelin Phosphodiesterase, Staphylococcus aureus}, issn = {1932-6203}, doi = {10.1371/journal.pone.0060013}, author = {Prabhakara, Sushma and Khedkar, Supriya and Shambat, Srikanth Mairpady and Srinivasan, Rajalakshmi and Basu, Atanu and Norrby-Teglund, Anna and Seshasayee, Aswin Sai Narain and Arakere, Gayathri} } @article {484, title = {Genomic analysis reveals epistatic silencing of "expensive" genes in Escherichia coli K-12. [Next Generation Genomics facility]}, journal = {Mol Biosyst}, volume = {9}, year = {2013}, month = {2013 Aug}, pages = {2021-33}, abstract = {

A barrier for horizontal gene transfer is high gene expression, which is metabolically expensive. Silencing of horizontally-acquired genes in the bacterium Escherichia coli is caused by the global transcriptional repressor H-NS. The activity of H-NS is enhanced or diminished by other proteins including its homologue StpA, and Hha and YdgT. The interconnections of H-NS with these regulators and their role in silencing gene expression in E. coli are not well understood on a genomic scale. In this study, we use transcriptome sequencing to show that there is a bi-layered gene silencing system - involving the homologous H-NS and StpA - operating on horizontally-acquired genes among others. We show that H-NS-repressed genes belong to two types, termed "epistatic" and "unilateral". In the absence of H-NS, the expression of "epistatically controlled genes" is repressed by StpA, whereas that of "unilaterally controlled genes" is not. Epistatic genes show a higher tendency to be non-essential and recently acquired, when compared to unilateral genes. Epistatic genes reach much higher expression levels than unilateral genes in the absence of the silencing system. Finally, epistatic genes contain more high affinity H-NS binding motifs than unilateral genes. Therefore, both the DNA binding sites of H-NS as well as the function of StpA as a backup system might be selected for silencing highly transcribable genes.

}, keywords = {Binding Sites, DNA-Binding Proteins, Epistasis, Genetic, Escherichia coli K12, Escherichia coli Proteins, Fimbriae Proteins, Gene Expression Regulation, Bacterial, Gene Silencing, Gene Transfer, Horizontal, Genome, Bacterial, Molecular Chaperones, Protein Binding, Repressor Proteins, Sequence Analysis, DNA, Transcription, Genetic, Transcriptome}, issn = {1742-2051}, doi = {10.1039/c3mb70035f}, author = {Srinivasan, Rajalakshmi and Chandraprakash, Deepti and Krishnamurthi, Revathy and Singh, Parul and Scolari, Vittore F and Krishna, Sandeep and Seshasayee, Aswin Sai Narain} } @article {717, title = {Developmental heterogeneity in DNA packaging patterns influences T-cell activation and transmigration.}, journal = {PLoS One}, volume = {7}, year = {2012}, month = {2012}, pages = {e43718}, abstract = {

Cellular differentiation programs are accompanied by large-scale changes in nuclear organization and gene expression. In this context, accompanying transitions in chromatin assembly that facilitates changes in gene expression and cell behavior in a developmental system are poorly understood. Here, we address this gap and map structural changes in chromatin organization during murine T-cell development, to describe an unusual heterogeneity in chromatin organization and associated functional correlates in T-cell lineage. Confocal imaging of DNA assembly in cells isolated from bone marrow, thymus and spleen reveal the emergence of heterogeneous patterns in DNA organization in mature T-cells following their exit from the thymus. The central DNA pattern dominated in immature precursor cells in the thymus whereas both central and peripheral DNA patterns were observed in na{\"\i}ve and memory cells in circulation. Na{\"\i}ve T-cells with central DNA patterns exhibited higher mechanical pliability in response to compressive loads in vitro and transmigration assays in vivo, and demonstrated accelerated expression of activation-induced marker CD69. T-cell activation was characterized by marked redistribution of DNA assembly to a central DNA pattern and increased nuclear size. Notably, heterogeneity in DNA patterns recovered in cells induced into quiescence in culture, suggesting an internal regulatory mechanism for chromatin reorganization. Taken together, our results uncover an important component of plasticity in nuclear organization, reflected in chromatin assembly, during T-cell development, differentiation and transmigration.

}, keywords = {Animals, Antigens, CD, Antigens, Differentiation, T-Lymphocyte, Bone Marrow Cells, Cell Lineage, Cell Movement, Cell Nucleus, Chromatin, DNA, Hematopoietic Stem Cells, Lectins, C-Type, Lymphocyte Activation, Mice, Microscopy, Confocal, Models, Biological, Models, Statistical, Sequence Analysis, DNA, Spleen, T-Lymphocytes}, issn = {1932-6203}, doi = {10.1371/journal.pone.0043718}, author = {Gupta, Soumya and Marcel, Nimi and Talwar, Shefali and Garg, Megha and R, Indulaxmi and Perumalsamy, Lakshmi R and Sarin, Apurva and Shivashankar, G V} } @article {494, title = {Draft genome sequence of Staphylococcus aureus ST672, an emerging disease clone from India. [Next Generation Genomics facility]}, journal = {J Bacteriol}, volume = {194}, year = {2012}, month = {2012 Dec}, pages = {6946-7}, abstract = {

We report the draft genome sequence of methicillin-resistant Staphylococcus aureus (MRSA) strain ST672, an emerging disease clone in India, from a septicemia patient. The genome size is about 2.82 Mb with 2,485 open reading frames (ORFs). The staphylococcal cassette chromosome mec (SCCmec) element (type V) and immune evasion cluster appear to be different from those of strain ST772 on preliminary examination.

}, keywords = {Bacteremia, Bacterial Proteins, Bacterial Typing Techniques, Base Sequence, DNA, Bacterial, Genome, Bacterial, Humans, Methicillin-Resistant Staphylococcus aureus, Molecular Sequence Data, Open Reading Frames, Penicillin-Binding Proteins, Sequence Analysis, DNA, Staphylococcal Infections}, issn = {1098-5530}, doi = {10.1128/JB.01868-12}, author = {Khedkar, Supriya and Prabhakara, Sushma and Loganathan, Ramya Malarini and S, Chandana and Gowda, Malali and Arakere, Gayathri and Seshasayee, Aswin Sai Narain} } @article {492, title = {Draft genome sequence of the nitrophenol-degrading actinomycete Rhodococcus imtechensis RKJ300. [Next Generation Genomics facility]}, journal = {J Bacteriol}, volume = {194}, year = {2012}, month = {2012 Jul}, pages = {3543}, abstract = {

We report the 8.231-Mb genome sequence of Rhodococcus imtechensis RKJ300, isolated from pesticide-contaminated soil in Punjab, India. The genome sequence of the strain RKJ300 will be helpful in exploring the molecular pathways involved in the degradation of nitrophenols.

}, keywords = {Biodegradation, Environmental, Genome, Bacterial, India, Molecular Sequence Data, Nitrophenols, Pesticides, Rhodococcus, Sequence Analysis, DNA, Soil Microbiology, Soil Pollutants}, issn = {1098-5530}, doi = {10.1128/JB.00532-12}, author = {Vikram, Surendra and Kumar, Shailesh and Subramanian, Srikrishna and Raghava, Gajendra Pal Singh} }