Lamotrigine-mediated rescue of RsgA-deficient Escherichia coli reveals another role of IF2 in ribosome biogenesis.

RsgA (small ribosomal subunit, 30S, GTPase), a late-stage biogenesis factor, releases RbfA from 30S-RbfA complex. Escherichia coli ΔrsgA (deleted for rsgA) shows a slow growth phenotype and an increased accumulation of 17S rRNA (precursor of 16S rRNA) and the ribosomal subunits. Here, we show that the rescue of the ΔrsgA strain by multicopy infB (IF2) is enhanced by simultaneous overexpression of initiator tRNA (i-tRNA), suggesting a role of initiation complex formation in growth rescue. The synergistic effect of IF2/i-tRNA is accompanied by increased processing of 17S rRNA (to 16S), and protection of the 16S rRNA 3'-minor domain. Importantly, we show that an IF2-binding anticonvulsant drug, lamotrigine (Ltg), also rescues the ΔrsgA strain growth. The rescue is accompanied by increased processing of 17S rRNA, protection of the 3'-minor domain of 16S rRNA, and increased 70S ribosomes in polysome profiles. However, Ltg becomes inhibitory to the ΔrsgA strain whose growth was already rescued by an L83R mutation in rbfA. Interestingly, like wild-type infB, overproduction of LtgRinfB alleles (having indel mutations in their domain II) also rescues the ΔrsgA strain (independent of Ltg). Our observations suggest the dual role of IF2 in rescuing the ΔrsgA strain. First, together with i-tRNA, IF2 facilitates the final steps of processing of 17S rRNA. Second, a conformer of IF2 functionally compensates for RsgA, albeit poorly, during 30S biogenesis. IMPORTANCE: RsgA is a late-stage ribosome biogenesis factor. Earlier, infB (IF2) was isolated as a multicopy suppressor of the Escherichia coli ΔrsgA strain. How IF2 rescued the strain growth remained unclear. This study reveals that (i) the multicopy infB-mediated growth rescue of E. coli ΔrsgA and the processing of 17S precursor to 16S rRNA in the strain are enhanced upon simultaneous overexpression of initiator tRNA and (ii) a conformer of IF2, whose occurrence increases when IF2 is overproduced or when E. coli ΔrsgA is treated with Ltg (an anticonvulsant drug that binds to domain II of IF2), compensates for the function of RsgA. Thus, this study reveals yet another role of IF2 in ribosome biogenesis.

Physiological significance of the two isoforms of initiator tRNAs in Escherichia coli.

Escherichia coli possesses four initiator tRNA (i-tRNA) genes, three of which are present together as metZWV and the fourth one as metY. In E. coli B, all four genes (metZWV and metY) encode i-tRNAfMet1, in which the G at position 46 is modified to m7G46 by TrmB (m7G methyltransferase). However, in E. coli K, because of a single-nucleotide polymorphism, metY encodes a variant, i-tRNAfMet2, having an A in place of m7G46. We generated E. coli strains to explore the importance of this polymorphism in i-tRNAs. The strains were sustained either on metYA46 (metY of E. coli K origin encoding i-tRNAfMet2) or its derivative metYG46 (encoding i-tRNAfMet1) in single (chromosomal) or plasmid-borne copies. We show that the strains sustained on i-tRNAfMet1 have a growth fitness advantage over those sustained on i-tRNAfMet2. The growth fitness advantages are more pronounced for the strains sustained on i-tRNAfMet1 in nutrient-rich media than in nutrient-poor media. The growth fitness of the strains correlates well with the relative stabilities of the i-tRNAs in vivo. Furthermore, the atomistic molecular dynamics simulations support the higher stability of i-tRNAfMet1 than that of i-tRNAfMet2. The stability of i-tRNAfMet1 remains unaffected upon the deletion of TrmB. These studies highlight how metYG46 and metYA46 alleles might influence the growth fitness of E. coli under certain nutrient-limiting conditions. IMPORTANCE: Escherichia coli harbors four initiator tRNA (i-tRNA) genes: three of these at metZWV and the fourth one at metY loci. In E. coli B, all four genes encode i-tRNAfMet1. In E. coli K, because of a single-nucleotide polymorphism, metY encodes a variant, i-tRNAfMet2, having an A in place of G at position 46 of i-tRNA sequence in metY. We show that G46 confers stability to i-tRNAfMet1. The strains sustained on i-tRNAfMet1 have a growth fitness advantage over those sustained on i-tRNAfMet2. Strains harboring metYG46 (B mimic) or metYA46 (K mimic) show that while in the nutrient-rich media, the K mimic is outcompeted rapidly; in the nutrient-poor medium, the K mimic is outcompeted less rapidly.

Decreased sarcoplasmic reticulum phospholipids in human skeletal muscle are associated with metabolic syndrome.

Metabolic syndrome affects more than one in three adults and is associated with increased risk of diabetes, cardiovascular disease, and all-cause mortality. Muscle insulin resistance is a major contributor to the development of the metabolic syndrome. Studies in mice have linked skeletal muscle sarcoplasmic reticulum (SR) phospholipid composition to sarcoplasmic/endoplasmic reticulum Ca2+-ATPase activity and insulin sensitivity. To determine if the presence of metabolic syndrome alters specific phosphatidylcholine (PC) and phosphatidylethanolamine (PE) species in human SR, we compared SR phospholipid composition in skeletal muscle from sedentary subjects with metabolic syndrome and sedentary control subjects without metabolic syndrome. Both total PC and total PE were significantly decreased in skeletal muscle SR of sedentary metabolic syndrome patients compared with sedentary controls, particularly in female participants, but there was no difference in the PC:PE ratio between groups. Total SR PC levels, but not total SR PE levels or PC:PE ratio, were significantly negatively correlated with BMI, waist circumference, total fat, visceral adipose tissue, triglycerides, fasting insulin, and homeostatic model assessment for insulin resistance. These findings are consistent with the existence of a relationship between skeletal muscle SR PC content and insulin resistance in humans.

Phyto-safe in vitro regeneration and harnessing antimicrobial-resistant endophytes as bioinoculants for enhanced growth and secondary metabolites yield in Nilgirianthus ciliatus.

Nilgirianthus ciliatus, extensively exploited for its pharmacological properties, is now classified as vulnerable. In vitro micropropagation offers a sustainable approach for ecological conservation and rational utilization of this biodiversity resource. This study aimed to reduce endophytes during in vitro propagation and isolating antimicrobial-resistant endophytes from N. ciliatus by employing various concentrations and exposure times of Plant Preservative Mixture (PPM). Optimal results were observed when nodal explants treated with 0.3% PPM for 8 h, followed by inoculation in Murashige and Skoog (MS) medium supplemented with 3 mg/L 6-benzylaminopurine (BAP) and 0.3% PPM. This protocol achieved 82% shoot regeneration with minimal endophytic contamination, suggesting that the duration of explant exposure to PPM significantly influences endophyte reduction. Two antimicrobial-resistant endophytes were isolated and identified as Bacillus cereus and Acinetobacter pittii through 16S rDNA sequencing. These endophytes exhibited plant growth-promoting characteristics, including amylolytic, proteolytic, lipolytic activities, indole-3-acetic acid production, phosphate solubilization, and stress tolerance. In vivo application of these endophytes as bioinoculants to N. ciliatus not only improved growth parameters but also significantly increased the levels of pharmacologically important compounds, squalene, and stigmasterol, as confirmed by High-performance thin-layer chromatography (HPTLC). This study demonstrates that PPM is a promising alternative for sustainable micropropagation of N. ciliatus. Furthermore, it highlights the potential of antimicrobial-resistant endophytes as bioinoculants to improve growth and medicinal value, offering a sustainable solution for conservation and large-scale cultivation of this species.

Promoter of COR2-like gene is a stress inducible regulatory region in banana.

A promoter is a crucial component in driving the expression of a transgene of interest for biotechnological applications in crop improvement and thus characterization of varied regulatory regions is essential. Here, we identified the promoter of COR2-like (codeinone reductase-like) from banana and characterized its tissue specific and stress inducible nature. MusaCOR2-like of banana is closely related to COR2 and CHR (chalcone reductase) sequences from different plant species and contains signature sequences including a catalytic tetrad typical of proteins with aldo-keto reductase activity. Transcript level of MusaCOR2-like was strongly induced in response to drought, salinity and exposure of signaling molecules such as abscisic acid, methyl-jasmonate and salicylic acid. Induction of MusaCOR2-like under stress strongly correlated with the presence of multiple cis-elements associated with stress responses in the PMusaCOR2-like sequence isolated from Musa cultivar Rasthali. Transgenic tobacco lines harbouring PMusaCOR2-like-GUS displayed visible GUS expression in vascular tissue of leaves and stem while its expression was undetectable in roots under control conditions. Exposure to drought, salinity and cold strongly induced GUS expression from PMusaCOR2-like-GUS in transgenic tobacco shoots in a window period of 3H to 12H. Applications of salicylic acid, methyl-jasmonate, abscisic acid and ethephon also activate GUS in transgenic shoots at different period, with salicylic acid and abscisic acid being the stronger stimulants of PMusaCOR2-like. Using PMusaCOR2-like-GUS fusion and expression profiling, the current study sheds insights into a complex regulation of COR2-like, one of the least studied genes of secondary metabolite pathway in plants.

Aerosol-PM2.5 Dynamics: In-situ and satellite observations under the influence of regional crop residue burning in post-monsoon over Delhi-NCR, India.

The increasing air pollution in the urban atmosphere is adversely impacts the environment, climate and human health. The alarming degradation of air quality, atmospheric conditions, economy and human life due to air pollution needs significant in-depth studies to ascertain causes, contributions and impacts for developing and implementing an effective policy to combat these issues. This work lies in its multifaceted approach towards comprehensive understanding and mitigating severe pollution episodes in Delhi and its surrounding areas. We investigated the aerosol dynamics in the post-monsoon season (PMS) from 2019 to 2022 under the influence of both crop residue burning and meteorological conditions. The study involves a broad spectrum of factors, including PM2.5 concentrations, active fire events, and meteorological parameters, shedding light on previously unexplored studies. The average AOD550 (0.79) and PM2.5 concentration (140.12 µg/m³) were the highest in 2019. PM2.5 was higher from mid-October to mid-November each year, exceeding the WHO guideline of 15 µg/m³ (24 h) by 27-34 times, signifying a public health emergency. A moderate to strong correlation between PM2.5 and AOD was found (r = 0.65) in 2021. The hotspot region accounts for almost 50% (2019), 47.51% (2020), 57.91% (2021) and 36.61% (2022) of the total fire events. A statistically significant negative non-linear correlation (r) was observed between wind speed (WS) and both AOD and PM2.5 concentration, influencing air quality over the region. HYSPLIT model and Windrose result show the movement of air masses predominated from the North and North-West direction during PMS. This study suggest to promotes strategies such as alternative waste management, encouraging modern agricultural practices in hot-spot regions, and enforcing strict emission norms for industries and vehicles to reducing air pollution and its detrimental effects on public health in the region and also highlights the need for future possibilities of research to attract the global attention.

A novel thermotolerant L-rhamnose isomerase variant for biocatalytic conversion of D-allulose to D-allose.

A novel L-rhamnose isomerase was identified and cloned from an extreme-temperature aquatic habitat metagenome. The deduced amino acid sequence homology suggested the possible source of this metagenomic sequence to be Chloroflexus islandicus. The gene expression was performed in a heterologous host, Escherichia coli, and the recombinant protein L-rhamnose isomerase (L-RIM) was extracted and purified. The catalytic function of L-RIM was characterized for D-allulose to D-allose bioconversion. D-Allose is a sweet, rare sugar molecule with anti-tumour, anti-hypertensive, cryoprotective, and antioxidative properties. The characterization experiments showed L-RIM to be a Co++- or Mn++-dependent metalloenzyme. L-RIM was remarkably active (~ 80%) in a broad spectrum of pH (6.0 to 9.0) and temperature (70 to 80 °C) ranges. Optimal L-RIM activity with D-allulose as the substrate occurred at pH 7.0 and 75 °C. The enzyme was found to be excessively heat stable, displaying a half-life of about 12 days and 5 days at 65 °C and 70 °C, respectively. L-RIM catalysis conducted at slightly acidic pH of 6.0 and 70 °C achieved biosynthesis of about 30 g L-1 from 100 g L-1 D-allulose in 3 h. KEY POINTS: • The present study explored an extreme temperature metagenome to identify a novel gene that encodes a thermostable l-rhamnose isomerase (L-RIM) • L-RIM exhibits substantial (80% or more) activity in a broad spectrum of pH (6.0 to 9.0) and temperature (70 to 80 °C) ranges • L-RIM is excessively heat stable, displaying a half-life of about 12 days and 5 days at 65 °C and 70 °C, respectively.

NGS-Based Metagenomics Depicting Taxonomic and Functional Insights into North-Western Himalayan Hot Springs.

Hot springs have tremendous significance due to their divulging physiochemical features. In the recent past, metagenomics has emerged as a unique methodology to explore microbiota as well as new biocatalysts possessing advantageous biochemical properties from hot springs. In the present study, metagenomics has been employed for microbial diversity exploration and identification of genes involved in various metabolic pathways among two hot springs, Manikaran and Tatapani, located in Himachal Pradesh, India. Taxonomic analysis of both metagenomes revealed the dominance of the Proteobacteria phylum. Genomic signatures of other bacterial phyla such as Chloroflexi, Actinobacteria, Bacteroidetes, Cyanobacteria, Planctomycetes, and Firmicutes were also found in significant abundance in both the metagenomes. The abundance of microorganisms belonging to genera, especially Nitrospira, Thauera, Meiothermus, Thiobacillus, Massilia, and Anaerolinea, was reported to be prevalent in the hot springs. A significant amount of metagenomic data remained taxonomically unclassified, which indeed emphasizes the scientific importance of these thermoaquatic niches. The functional potential analysis of both metagenomes revealed pathways related to carbohydrate metabolism, followed by amino acid metabolism, energy metabolism, genetic information processing, metabolism of cofactors and vitamins, membrane transporter, and signal transduction. Exploration of biomass-modifying biocatalysts enumerated the presence of glycoside hydrolases, glycosyl transferases, polysaccharide lyases, and carbohydrate esterases in the metagenomic data. Together, these findings offer an in-depth understanding of the microbial inhabitants in North-Western Himalayan hot springs and their underlying potential for various biotechnological and industrial applications. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-024-01248-z.

Lactic acid bacteria in the functional food industry: biotechnological properties and potential applications.

With the growing demand for functional foods having better nutraceutical properties, lactic acid bacteria (LAB) has become an important industrial microorganism. LAB play a significant role in the functional food industry by exhibiting probiotic properties and has the ability to produce various biologically active metabolites such as γ-aminobutyric acid (GABA), exopolysaccharides (EPSs), conjugated linoleic acid (CLA), bacteriocins, reuterin and reutericyclin, which provides enhanced nutraceutical properties to the final food products. LAB are also known to produce several specific enzymes essential for producing substrate-derived bioactive compounds, such as polyphenols, bioactive peptides, inulin-type fructans and ß-glucans, fatty acids, and polyols. These compounds exhibit many health benefits, including better mineral absorption, oxidative stress protection, blood glucose and cholesterol-lowering properties, prevention of gastrointestinal tract infections and improved cardiovascular function. Further, metabolically engineered LAB have been widely used for the nutritive enhancement of different food products and the application of CRISPR-Cas9 holds tremendous potential for the engineering of food cultures. This review provides an overview of the use of LAB as probiotics, its application in producing fermented foods and nutraceutical products, and its health benefits on the host.

Phylogenomics of transcriptionally active AP2/ERF and bHLH transcription factors and study of their promoter regions in Nothapodytes nimmoniana (J.Graham) Mabb.

Nothapodytes nimmoniana is a medicinally important plant producing anticancer monoterpene indole alkaloid (MIA), camptothecin (CPT). The CPT is synthesised through the strictosidine intermediate following the MIA pathway; however, transcriptional regulation of CPT pathway is still elusive in N. nimmoniana. Biosynthesis of MIA is regulated by various transcription factors (TFs) belonging to AP2/ERF, bHLH, MYB, and WRKY families. The present study identified transcriptionally active full-length 105 AP2/ERF and 68 bHLH family TFs from the N. nimmoniana. AP2/ERF TFs were divided into three subfamilies along with a soloist, while bHLH TFs were divided into 10 subfamilies according to their phylogenetic similarities. Three group IXa ERFs, Nn-ERF22, Nn-ERF29, and Nn-ERF41, one subfamily IVa TF Nn-bHLH7, and three subfamilies IIIe Nn-bHLH33, Nn-bHLH51, and Nn-bHLH52 clustered with the TFs regulating alkaloid biosynthesis in Catharanthus roseus, tomato, tobacco, and Artemisia annua. Expression of these TFs in N. nimmoniana was higher in roots, which is a primary CPT accumulating tissue. Moreover, genome skimming approach was used to reconstruct the promoter regions of candidate ERF genes to identify the cis-regulatory elements. The presence of G-boxes and other jasmonic acid-responsive elements in the promoter suggests the regulation of ERFs by bHLHs. The present study effectively generated and used genomics resource for characterisation of regulatory TFs from non-model medicinal plant.

Lamotrigine compromises the fidelity of initiator tRNA recruitment to the ribosomal P-site by IF2 and the RbfA release from 30S ribosomes in Escherichia coli.

Lamotrigine (Ltg), an anticonvulsant drug, targets initiation factor 2 (IF2), compromises ribosome biogenesis and causes toxicity to Escherichia coli. However, our understanding of Ltg toxicity in E. coli remains unclear. While our in vitro assays reveal no effects of Ltg on the ribosome-dependent GTPase activity of IF2 or its role in initiation as measured by dipeptide formation in a fast kinetics assay, the in vivo experiments show that Ltg causes accumulation of the 17S precursor of 16S rRNA and leads to a decrease in polysome levels in E. coli. IF2 overexpression in E. coli increases Ltg toxicity. However, the overexpression of initiator tRNA (i-tRNA) protects it from the Ltg toxicity. The depletion of i-tRNA or overexpression of its 3GC mutant (lacking the characteristic 3GC base pairs in anticodon stem) enhances Ltg toxicity, and this enhancement in toxicity is synthetic with IF2 overexpression. The Ltg treatment itself causes a detectable increase in IF2 levels in E. coli and allows initiation with an elongator tRNA, suggesting compromise in the fidelity/specificity of IF2 function. Also, Ltg causes increased accumulation of ribosome-binding factor A (RbfA) on 30S ribosomal subunit. Based on our genetic and biochemical investigations, we show that Ltg compromises the function of i-tRNA/IF2 complex in ribosome maturation.

Editing of TOM1 gene in tobacco using CRISPR/Cas9 confers resistance to Tobacco mosaic virus.

BACKGROUND: Genome editing technology has become one of the excellent tools for precise plant breeding to develop novel plant germplasm. The Tobacco mosaic virus (TMV) is the most prominent pathogen that infects several Solanaceae plants, such as tobacco, tomato, and capsicum, which requires critical host factors for infection and replication of its genomic RNA in the host. The Tobamovirus multiplication (TOM) genes, such as TOM1, TOM2A, TOM2B, and TOM3, are involved in the multiplication of Tobamoviruses. TOM1 is a transmembrane protein necessary for efficient TMV multiplication in several plant species. The TOM genes are crucial recessive resistance genes that act against the tobamoviruses in various plant species. METHODS AND RESULTS: The single guided RNA (sgRNA) was designed to target the first exon of the NtTOM1 gene and cloned into the pHSE401 vector. The pHSE401-NtTOM1 vector was introduced into Agrobacterium tumefaciens strain LBA4404 and then transformed into tobacco plants. The analysis on T0 transgenic plants showed the presence of the hptII and Cas9 transgenes. The sequence analysis of the NtTOM1 from T0 plants showed the indels. Genotypic evaluation of the NtTOM1 mutant lines displayed the stable inheritance of the mutations in the subsequent generations of tobacco plants. The NtTOM1 mutant lines successfully conferred resistance to TMV. CONCLUSIONS: CRISPR/Cas genome editing is a reliable tool for investigating gene function and precision breeding across different plant species, especially the species in the Solanaceae family.

Integration of hydrogeological data, GIS and AHP techniques applied to delineate groundwater potential zones in sandstone, limestone and shales rocks of the Damoh district, (MP) central India.

The Damoh district, which is located in the central India and characterized by limestone, shales, and sandstone compact rock. The district has been facing groundwater development challenges and problems for several decades. To facilitate groundwater management, it is crucial to monitoring and planning based on geology, slope, relief, land use, geomorphology, and the types of the basaltic aquifer in the drought-groundwater deficit area. Moreover, the majority of farmers in the area are heavily dependent on groundwater for their crops. Therefore, delineation of groundwater potential zones (GPZ) is essential, which is defined based on various thematic layers, including geology, geomorphology, slope, aspect, drainage density, lineament density, topographic wetness index (TWI), topographic ruggedness index (TRI), and land use/land cover (LULC). The processing and analysis of this information were carried out using Geographic Information System (GIS) and Analytic Hierarchy Process (AHP) methods. The validity of the results was trained and tested using Receiver Operating Characteristic (ROC) curves, which showed training and testing accuracies of 0.713 and 0.701, respectively. The GPZ map was classified into five classes such as very high, high, moderate, low, and very low. The study revealed that approximately 45% of the area falls under the moderate GPZ, while only 30% of the region is classified as having a high GPZ. The area receives high rainfall but has very high surface runoff due to no proper developed soil and lack of water conservation structures. Every summer season show a declined groundwater level. In this context, results of study area are useful to maintain the groundwater under climate change and summer season. The GPZ map plays an important role in implementing artificial recharge structures (ARS), such as percolation ponds, tube wells, bore wells, cement nala bunds (CNBs), continuous contour trenching (CCTs), and others for development of ground level. This study is significant for developing sustainable groundwater management policies in semi-arid regions, that are experiencing climate change. Proper groundwater potential mapping and watershed development policies can help mitigate the effects of drought, climate change, and water scarcity, while preserving the ecosystem in the Limestone, Shales, and Sandstone compact rock region. The results of this study are essential for farmers, regional planners, policy-makers, climate change experts, and local governments, enabling them to understand the groundwater development possibilities in the study area.

Management of non-functioning kidney due to pelvi-ureteric junction obstruction in pediatric age group: an observational study.

INTRODUCTION: A non-functional kidney (NFK) has been defined as one having paper-thin parenchyma, and split renal function (SRF) of < 10% on a nuclear scan. There are differences of opinion about nephrectomy or pyeloplasty in these patients. The present study was conducted to assess our management strategy of renal salvage for NFK. MATERIALS AND METHODS: It was a retrospective cohort study from January 2015 to July 2022, patients having SRF < 10% were included. These patients underwent ultrasound-guided percutaneous nephrostomy (PCN). A repeat nuclear scan was performed after 3 months. If SRF increased to > 10%, pyeloplasty was performed. RESULTS: Fifteen patients were managed. The mean age was 24.67 ± 23.61 months. Male to female ratio was 4:1. The initial mean SRF was 6.67 ± 2.85, which improved to 16.80 ± 4.69 after 3 months of placing the PCN (p < 0.001). The corresponding changes in the mean effective renal plasma flow (ERPF) were 60.13 ± 24.08 to 106.53 ± 24.61 (p < 0.001). There was no complaint after the placement of PCN. All patients underwent dismembered pyeloplasty. CONCLUSION: In NFK due to PUJO, expectant treatment in form of PCN followed by pyeloplasty appears to be the primary treatment modality, and nephrectomy may not be needed in any of them.

Land cover and crop types mapping using different spatial resolution imagery in a Mediterranean irrigated area.

Crop type identification is critical for agricultural sustainability policy development and environmental assessments. Therefore, it is important to obtain their spatial distribution via different approaches. Medium-, high- and very high-resolution optical satellite sensors are efficient tools for acquiring this information, particularly for challenging studies such as those conducted in heterogeneous agricultural fields. This research examined the ability of four multitemporal datasets (Sentinel-1-SAR (S1), Sentinel-2-MSI (S2), RapidEye (RE), and PlanetScope (PS)) to identify land cover and crop types (LCCT) in a Mediterranean irrigated area. To map LCCT distribution, a supervised pixel-based classification is adopted using Support Vector Machine with a radial basis function kernel (SVMRB) and Random Forest (RF). Thus, LCCT maps were generated into three levels, including six (Level I), ten (Level II), and fourteen (Level III) classes. Overall, the findings revealed high overall accuracies of >92%, >83%, and > 81% for Level I, Level II, and Level III, respectively, except for Sentinel-1. It was found that accuracy improves considerably when the number of classes decreases, especially when cropland or non-cropland classes are grouped into one. Furthermore, there was a similarity in performance between S2 alone and S1S2. PlanetScope LCCT classifications outperform other sensors. In addition, the present study demonstrated that SVM achieved better performances against RF and can thereby effectively extract LCCT information from high-resolution imagery as PlanetScope.

Metagenomic views on taxonomic and functional profiles of the Himalayan Tsomgo cold lake and unveiling its deterzome potential.

Cold habitat is considered a potential source for detergent industry enzymes. This study aims at the metagenomic investigation of Tsomgo lake for taxonomic and functional annotation, unveiling the deterzome potential of the residing microbiota at this site. The present investigation revealed molecular profiling of microbial community structure and functional potential of the high-altitude Tsomgo lake samples of two different temperatures, harvested during March and August. Bacteria were found to be the most dominant phyla, with traces of genomic pieces of evidence belonging to archaea, viruses, and eukaryotes. Proteobacteria and Actinobacteria were noted to be the most abundant bacterial phyla in the cold lake. In-depth metagenomic investigation of the cold aquatic habitat revealed novel genes encoding detergent enzymes, amylase, protease, and lipase. Further, metagenome-assembled genomes (MAGs) belonging to the psychrophilic bacterium, Arthrobacter alpinus, were constructed from the metagenomic data. The annotation depicted the presence of detergent enzymes and genes for low-temperature adaptation in Arthrobacter alpinus. Psychrophilic microbial isolates were screened for lipase, protease, and amylase activities to further strengthen the metagenomic findings. A novel strain of Acinetobacter sp. was identified with the dual enzymatic activity of protease and amylase. The bacterial isolates exhibited hydrolyzing activity at low temperatures. This metagenomic study divulged novel genomic resources for detergent industry enzymes, and the bacterial isolates secreting cold-active amylase, lipase, and protease enzymes. The findings manifest that Tsomgo lake is a potential bioresource of cold-active enzymes, vital for various industrial applications.

Cold-adaptive traits identified by comparative genomic analysis of a lipase-producing Pseudomonas sp. HS6 isolated from snow-covered soil of Sikkim Himalaya and molecular simulation of lipase for wide substrate specificity.

The genomic analysis of industrially important bacteria can help in understanding their capability to withstand extreme environments and shed light on their metabolic capabilities. The whole genome of a previously reported broad temperature active lipase-producing Pseudomonas sp. HS6, isolated from snow-covered soil of the Sikkim Himalayan Region, was analyzed to understand the capability of the bacterium to withstand cold temperatures and study its lipolytic nature. Pseudomonas sp. HS6 was found to be psychrotolerant with an optimal growth temperature ranging between 25 and 30 °C, with the ability to grow at 5 °C. The genome harbours various cold-adaptation genes, such as cold-shock proteins, fatty acid alteration, and cold stress-tolerance genes, supporting the psychrotolerant nature of the organism. The comparative analysis of Pseudomonas sp. HS6 genome showed the presence of amino acid substitutions in genes that favor efficient functioning and flexibility at cold temperatures. Genome mining revealed the presence of four triacylglycerol lipases, among which the putative lipase 3 was highly similar to the broad temperature-active lipase purified and characterized in our previous study. In silico studies of putative lipase 3 revealed broad substrate specificity with partial and no inhibition of the enzyme activity in the presence of PMSF and orlistat. The presence of genes associated with cold adaptations and true lipases with activity at broad temperature and substrate specificity in the genome of Pseudomonas sp. HS6 makes this bacterium a suitable candidate for industrial applications.

MusaATAF2 like protein, a stress-related transcription factor, induces leaf senescence by regulating chlorophyll catabolism and H2 O2 accumulation.

NAC transcription factors are known for their diverse role in plants. In this study, we have demonstrated the role of MusaATAF2, a banana NAC transcription factor, in leaf senescence. Its expression gets strongly up-regulated during the early stress responses of drought and high salinity exposure and down-regulated under ABA application, which suggests MusaATAF2 is a stress-related NAC transcription factor. To study the role of MusaATAF2 in banana, we have transformed the banana embryogenic cells with MusaATAF2 coding region and generated transgenic banana plants. Overexpression of MusaATAF2 in banana plants caused yellow leaf phenotype under control condition, suggesting its role as a senescence-associated transcription factor. Transgenic banana leaves exhibited low chlorophyll content and high H2 O2 accumulation. Hormone analysis of the leaves demonstrated a higher accumulation of ABA in the transgenic plants than the controls. Transgenic plants overexpressing MusaATAF2 have a higher transcript abundance of two chlorophyll catabolic pathway genes (PAO and HCAR) and lower transcript abundance of ROS scavenging enzymes (TDP, THIO, CAT, APX, and PRXDN) than control. Together, all these analyses indicate that MusaATAF2 induces senescence by inducing chlorophyll degradation and H2 O2 accumulation in banana plants and controls its own expression using an ABA-dependent feedback loop.

An acid-tolerant and cold-active ß-galactosidase potentially suitable to process milk and whey samples.

A novel ß-galactosidase gene (galM) was cloned from an aquatic habitat metagenome. The analysis of its translated sequence (GalM) revealed its phylogenetic closeness towards Verrucomicrobia sp. The sequence comparison and homology structure analysis designated it a member of GH42 family. The three-dimensional homology model of GalM depicted a typical (ß/α)8 TIM-barrel containing the catalytic core. The gene (galM) was expressed in a heterologous host, Escherichia coli, and the purified protein (GalM) was subjected to biochemical characterization. It displayed ß-galactosidase activity in a wide range of pH (2.0 to 9.0) and temperature (4 to 60 °C). The heat exposed protein showed considerable stability at 40 and 50 °C, with the half-life of about 100 h and 35 h, respectively. The presence of Na, Mg, K, Ca, and Mn metals was favorable to the catalytic efficiency of GalM, which is a desirable catalytic feature, as these metals exist in milk. It showed remarkable tolerance of glucose and galactose in the reaction. Furthermore, GalM discerned transglycosylation activity that is useful in galacto-oligosaccharides' production. These biochemical properties specify the suitability of this biocatalyst for milk and whey processing applications. KEY POINTS: • A novel ß-galactosidase gene was identified and characterized from an aquatic habitat. • It was active in extreme acidic to mild alkaline pH and at cold to moderate temperatures. • The ß-galactosidase was capable to hydrolyze lactose in milk and whey.

MusaATAF2-like protein regulates shoot development and multiplication by inducing cytokinin hypersensitivity and flavonoid accumulation in banana plants.

KEY MESSAGE: Senescence-associated transcription factor ATAF2 regulates cytokinin signalling and in vitro shoot multiplication in banana plants. MusaATAF2-like protein is a stress-related NAC transcription factor of banana. It regulates senescence in rooted banana plants. During the early stages of plant development under in vitro conditions, the presence of 6-benzylaminopurine leads to vigorous shoot multiplication. The major contributor to plant shoot multiplication is auxin to cytokinin ratio and their signalling components. The LC-MS analysis of transgenic banana plants overexpressing MusaATAF2 indicated significantly higher cytokinin content and remarkably lower auxin content. Auxin transport has been reported to be inhibited by flavonoids. Their significantly higher abundance in the shoot tissues in transgenic lines suggested potential negative regulation of auxin signalling in transgenic plants. Enhanced shoot multiplication in transgenic lines was further corroborated by reduced transcript abundance of type-A Arabidopsis response regulator-like genes (inhibitors of cytokinin signalling pathway) and higher expression of Arabidopsis histidine kinase-like genes and type-B Arabidopsis response regulator-like genes (positive regulators of cytokinin signalling pathway) in transgenic lines. Altogether, the data concludes that MusaATAF2 induces cytokinin hypersensitivity in banana shoots by modulating/regulating the cytokinin signalling components and flavonoids content.