Label-free liquid crystal-based optical detection of norfloxacin using an aptamer recognition probe in soil and lake water.

Norfloxacin (NOX), a broad spectrum fluoroquinolone (FQ) antibiotic, is commonly detected in environmental residues, potentially contributing to biological drug resistance. In this paper, an aptamer recognition probe has been used to develop a label-free liquid crystal-based biosensor for simple and robust optical detection of NOX in aqueous solutions. Stimuli-receptive liquid crystals (LCs) have been employed to report aptamer-target binding events at the LC-aqueous interface. The homeotropic alignment of LCs at the aqueous-LC interface is due to the self-assembly of the cationic surfactant cetyltrimethylammonium bromide (CTAB). In the presence of the negatively charged NOX aptamer, the ordering changes to planar/tilted. On addition of NOX, the aptamer-NOX binding causes redistribution of CTAB at the LC-aqueous interface and the homeotropic orientation is restored. This results in a bright-to-dark optical transition under a polarized optical microscope (POM). This optical transition serves as a visual indicator to mark the presence of NOX. The devised aptasensor demonstrates high specificity with a minimum detection limit of 5 nM (1.596 ppb). Moreover, the application of the developed aptasensor for the detection of NOX in freshwater and soil samples underscores its practical utility in environmental monitoring. This proposed LC-based method offers several advantages over conventional detection techniques for a rapid, feasible and convenient way to detect norfloxacin.

Defective Mitochondrial Quality Control during Dengue Infection Contributes to Disease Pathogenesis.

Mitochondrial fitness is governed by mitochondrial quality control pathways comprising mitochondrial dynamics and mitochondrial-selective autophagy (mitophagy). Disruption of these processes has been implicated in many human diseases, including viral infections. Here, we report a comprehensive analysis of the effect of dengue infection on host mitochondrial homeostasis and its significance in dengue disease pathogenesis. Despite severe mitochondrial stress and injury, we observed that the pathways of mitochondrial quality control and mitochondrial biogenesis are paradoxically downregulated in dengue-infected human liver cells. This leads to the disruption of mitochondrial homeostasis and the onset of cellular injury and necrotic death in the infected cells. Interestingly, dengue promotes global autophagy but selectively disrupts mitochondrial-selective autophagy (mitophagy). Dengue downregulates the expression of PINK1 and Parkin, the two major proteins involved in tagging the damaged mitochondria for elimination through mitophagy. Mitophagy flux assays also suggest that Parkin-independent pathways of mitophagy are also inactive during dengue infection. Dengue infection also disrupts mitochondrial biogenesis by downregulating the master regulators PPARγ and PGC1α. Dengue-infected cells release mitochondrial damage-associated molecular patterns (mtDAMPs) such as mitochondrial DNA into the cytosol and extracellular milieu. Furthermore, the challenge of naive immune cells with culture supernatants from dengue-infected liver cells was sufficient to trigger proinflammatory signaling. In correlation with our in vitro observations, dengue patients have high levels of cell-free mitochondrial DNA in their blood in proportion to the degree of thrombocytopenia. Overall, our study shows how defective mitochondrial homeostasis in dengue-infected liver cells can drive dengue disease pathogenesis. IMPORTANCE Many viruses target host cell mitochondria to create a microenvironment conducive to viral dissemination. Dengue virus also exploits host cell mitochondria to facilitate its viral life cycle. Dengue infection of liver cells leads to severe mitochondrial injury and inhibition of proteins that regulate mitochondrial quality control and biogenesis, thereby disrupting mitochondrial homeostasis. A defect in mitochondrial quality control leads to the accumulation of damaged mitochondria and promotes cellular injury. This leads to the release of mitochondrial damage-associated molecular patterns (mt-DAMPs) into the cell cytoplasm and extracellular milieu. These mt-DAMPs activate the naive immune cells and trigger proinflammatory signaling, leading to the release of cytokines and chemokines, which may trigger systemic inflammation and contribute to dengue disease pathogenesis. In correlation with this, we observed high levels of cell-free mitochondrial DNA in dengue patient blood. This study provides insight into how the disruption of mitochondrial quality control in dengue-infected cells can trigger inflammation and drive dengue disease pathogenesis.

Normal weight central obesity and hypertension in India: Cross-sectional finding from LASI, 2017-19.

BACKGROUND AND AIM: The current public health guidelines for preventing and managing obesity still emphasize the importance of maintaining a normal Body Mass Index, while paying little attention to central obesity, which is common among the general population. Normal Weight Central Obesity (NWCO) is a less explored risk factor for hypertension in India. Therefore, this study aims to investigate the prevalence of NWCO and its association with hypertension in India. METHODS AND RESULTS: The cross-sectional study used data from the Longitudinal Aging Study in India (LASI), 2017-19, which included 54,016 participants (22,438 men and 31,578 women). Hypertension was evaluated following the JNC-VIII guidelines for the detection, evaluation, and treatment of hypertension. Anthropometric measurements were taken to identify NWCO. The study found that NWCO was more prevalent among women (33.9%) than men (17.8%), while men had a higher prevalence of hypertension (47.6%) than women (43.8%). In India, the state of Haryana had the highest proportion of NWCO among men (26.4%), while Kerala had the highest proportion among women (39.1%). Binary logistic regression analysis showed that NWCO was significantly associated with an increased risk of hypertension. The odds ratio (aOR) was 1.57 (95% CI 1.45-1.67, p < 0.001) in men and 1.53 (95% CI 1.43-1.63, p < 0.001) in women, compared to normal-weight study participants. CONCLUSIONS: The study emphasizes the importance of considering central obesity in individuals with a normal BMI when assessing cardiovascular risk, particularly for hypertension. State-specific data can help identify high-risk areas and facilitate targeted prevention and treatment strategies.

Gender differences in the association between physical frailty and life satisfaction among older adults in India.

BACKGROUND: One of the sustainable development goals' (SDGs) primary goals (Goal 3) is to ensure healthy lives and promote well-being for persons of all ages. While extensive literature documents the link between physical frailty and low life satisfaction (LLS) among older adults, research of this nature is limited within low and middle-income countries including India. The purpose of this study was to examine the association between physical frailty and life satisfaction among community-dwelling older men and women in India. METHODS: Data come from the 2017-18 wave 1 of the Longitudinal Ageing Study in India (LASI), with a sample of 30 390 individuals aged 60 and above (14 559 men and 15 831 women). Physical frailty was assessed using an adapted version of the frailty phenotype developed by Fried and colleagues. Ordered logistic regression models are employed to examine the association between physical frailty and life satisfaction. RESULTS: The prevalence of frailty was higher in older women than men (32.2% vs. 27.5%). Nearly 30.4% of men and 33.8% of women reported having LLS. However, after adjusting for the selected confounders, women were less likely (adjusted odds ratio [aOR]: 0.92; CI: 0.87-0.97) to report LLS compared to men. The physically frail older adults were more likely (aOR: 1.40; CI: 1.27-1.55) to report LLS relative to their physically stronger counterparts. Moreover, we found that frail older men had higher odds of reporting LLS than non-frail older men (aOR: 1.25; CI: 1.09-1.43). Also, non-frail older women had lower odds of reporting LLS than non-frail older men (aOR: 0.80; CI: 0.67-0.95). CONCLUSIONS: Findings of our study suggest that policies and programs to address later life well-being need to consider gender differences. Doing so would not only help identify older adults most at risk of LLS, but gender differentiated policies would help streamline health expenditures and costs typically relegated to assist all older adults without proper focus on the uniqueness of their social location.

Stereoselective total syntheses of (-)-hygrophorone A12, 4-O-acetyl-hygrophorone A12 and (+)-hygrophorone B12.

Total syntheses of anti-fungal cyclopentenones (-)-hygrophorone A12, 4-O-acetyl-hygrophorone A12 and (+)-hygrophorone B12 were achieved in high overall yields from d-(-)-tartaric acid. The key feature of these syntheses is the aqueous KOH-mediated diastereoselective intramolecular aldol reaction to form ß-hydroxy ketone with three contiguous chiral centres, which was further elaborated to (-)-hygrophorone A12 and (+)-hygrophorone B12. The synthetic route reported here is operationally simple and highly diastereoselective and is amenable for the synthesis of several analogues of hygrophorones.

A divergent chiron approach for the first total synthesis of (+)-pseudonocardide A, (+)-pseudonocardide C and an epimer of ent-pseudonocardide D.

A concise and divergent chiron approach for the first total synthesis of (+)-pseudonocardide A, (+)-pseudonocardide C and an epimer of ent-pseudonocardide D is reported starting from d-ribose. The salient features of this synthesis are a highly Z-selective Wittig olefination, one-pot formation of γ-butyrolactone and γ-butenolide through [1,4] O-to-O silyl migration followed by lactonization and an intramolecular oxa-Michael reaction.

Manganese co-localizes with calcium and phosphorus in Chlamydomonas acidocalcisomes and is mobilized in manganese-deficient conditions.

Exposing cells to excess metal concentrations well beyond the cellular quota is a powerful tool for understanding the molecular mechanisms of metal homeostasis. Such improved understanding may enable bioengineering of organisms with improved nutrition and bioremediation capacity. We report here that Chlamydomonas reinhardtii can accumulate manganese (Mn) in proportion to extracellular supply, up to 30-fold greater than its typical quota and with remarkable tolerance. As visualized by X-ray fluorescence microscopy and nanoscale secondary ion MS (nanoSIMS), Mn largely co-localizes with phosphorus (P) and calcium (Ca), consistent with the Mn-accumulating site being an acidic vacuole, known as the acidocalcisome. Vacuolar Mn stores are accessible reserves that can be mobilized in Mn-deficient conditions to support algal growth. We noted that Mn accumulation depends on cellular polyphosphate (polyP) content, indicated by 1) a consistent failure of C. reinhardtii vtc1 mutant strains, which are deficient in polyphosphate synthesis, to accumulate Mn and 2) a drastic reduction of the Mn storage capacity in P-deficient cells. Rather surprisingly, X-ray absorption spectroscopy, EPR, and electron nuclear double resonance revealed that only little Mn2+ is stably complexed with polyP, indicating that polyP is not the final Mn ligand. We propose that polyPs are a critical component of Mn accumulation in Chlamydomonas by driving Mn relocation from the cytosol to acidocalcisomes. Within these structures, polyP may, in turn, escort vacuolar Mn to a number of storage ligands, including phosphate and phytate, and other, yet unidentified, compounds.

Computational image analysis of the baseplate-tail complex of O1 ElTor vibriophage M4.

We performed an in-depth computational image analysis of the baseplate-tail complex of the M4 vibriophage and identified seven major densities in its baseplate, which notably share structural similarities with baseplate modules of a number of other bacteriophages belonging to different species. Employing computational analysis, we explained the helical organization of the sheath protein, wrapping the tail tube. Based on the results obtained in this work along with the proteomics information published previously, we are able to decipher the plausible roles assigned to the different components of the M4 baseplate during infection of the host.

Manganese Mapping Using a Fluorescent Mn2+ Sensor and Nanosynchrotron X-ray Fluorescence Reveals the Role of the Golgi Apparatus as a Manganese Storage Site.

Elucidating dynamics in transition-metal distribution and localization under physiological and pathophysiological conditions is central to our understanding of metal-ion regulation. In this Forum Article, we focus on manganese and specifically recent developments that point to the relevance of the Golgi apparatus in manganese detoxification when this essential metal ion is overaccumulated because of either environmental exposure or mutations in manganese efflux transporters. In order to further evaluate the role of the Golgi apparatus as a manganese-ion storage compartment under subcytotoxic manganese levels, we use a combination of confocal microscopy using a sensitive "turn-on" fluorescent manganese sensor, M1, and nanosynchrotron X-ray fluorescence imaging to show that manganese ions are stored in the Golgi apparatus under micromolar manganese exposure concentrations. Our results, along with previous reports on manganese accumulation, now indicate a central role of the Golgi apparatus in manganese storage and trafficking under subcytotoxic manganese levels and hint toward a possible role of the Golgi apparatus in manganese storage even under physiological conditions.

Structural analysis and proteomics studies on the Myoviridae vibriophage M4.

Bacteriophages play a crucial role in tracking the spread of bacterial epidemics. The frequent emergence of antibiotic-resistant bacterial strains throughout the world has motivated studies on bacteriophages that can potentially be used in phage therapy as an alternative to conventional antibiotic treatment. A recent outbreak of cholera in Haiti took many lives due to a rapid development of resistance to the available antibiotics. The properties of vibriophages, bacteriophages that infect Vibrio cholerae, are therefore of practical interest. A detailed understanding of the structure and assembly of a vibriophage is potentially useful in developing phage therapy against cholera as well as for fabricating artificial nanocontainers. Therefore, the aim of the present study was to determine the three-dimensional organization of vibriophage M4 at sub-nanometer resolution by electron microscopy and single-particle analysis techniques to facilitate its use as a therapeutic agent. We found that M4 has a large capsid with T = 13 icosahedral symmetry and a long contractile tail. This double-stranded DNA phage also contains a head-to-tail connector protein complex that joins the capsid to the tail and a prominent baseplate at the end of the tail. This study also provides information regarding the proteome of this phage, which is proteins similar to that of other Myoviridae phages, and most of the encoded proteins are structural proteins that form the exquisite architecture of this bacteriophage.

Correction to: Structural analysis and proteomics studies on the Myoviridae vibriophage M4.

Unfortunately, the original article was published with an incorrect figure. Figure 11 contains errors and needs to be withdrawn.

A Sensitive Water-Soluble Reversible Optical Probe for Hg2+ Detection.

We report the serendipitous discovery of an optical mercury sensor while trying to develop a water-soluble manganese probe. The sensor is based on a pentaaza macrocycle conjugated to a hemicyanine dye. The pentaaza macrocycle earlier designed in our group was used to develop photoinduced electron transfer (PET)-based "turn-on" fluorescent sensors for manganese. (1) In an attempt to increase the water-solubility of the manganese sensors we changed the dye from BODIPY to hemicyanine. The resultant molecule qHCM afforded a distinct reversible change in the absorption features and a concomitant visible color change upon binding to Hg2+ ions, leading to a highly water-soluble mercury sensor with a 10 ppb detection limit. The molecule acts as a reversible "ON-OFF" fluorescent sensor for Hg2+ with a 35 times decrease in the emission intensity in the presence of 1 equiv of Hg2+ ions. We have demonstrated the applicability of the probe for detecting Hg2+ ions in living cells and in live zebrafish larvae using confocal fluorescence microscopy with visible excitation. High selectivity and sensitivity toward Hg2+ detection make qHCM an attractive probe for detecting Hg2+ in contaminated water sources, which is a major environmental toxicity concern. We have scrutinized the altered metal-ion selectivity of the probe using density functional theory (DFT) and time-dependent DFT calculations, which show that a PET-based metal-sensing scheme is not operational in qHCM. 1H NMR studies and DFT calculations indicate that Hg2+ ions coordinate to oxygen-donor atoms from both the chromophore and macrocycle, leading to sensitive mercury detection.

Preliminary Characterization of El Tor Vibriophage M4.

AIMS: The aim of the present study is the preliminary characterization of an El Tor vibriophage M4 (ATCC 51352-B4). METHODS: We studied the growth characteristics and sustainability of this phage under various stresses like temperature, pH, and UV. The phage morphology and phage genome were also examined using electron microscopy. RESULTS: Sustainability studies showed that the phage is more stable in acidic conditions, which is very uncommon among vibriophages. Studies also showed that M4 is a thermostable phage and it is inactivated by temperatures above 60°C but, like other phages, UV has a high inactivating effect on it. Morphological and genomic studies by electron microscopy showed that this phage has a long contractile tail and a big head. The genome is linear and about 120 kb in length. The genome also has a high packaging density as the value of Vm (the volume occupied per Da of biological macromolecule) is low for this phage. The phage-bacterial interaction was studied by negative staining as well as ultrathin sectioning methods. CONCLUSIONS: M4 belongs to the Myoviridae family and it is generally thermostable. It is prone to destruction by alkali and UV. It also has a large DNA which is densely packed inside of a big capsid.

Understanding Frailty: Perspectives and Experiences of Rural Older Adults in India.

OBJECTIVES: In India, frailty has been predominantly studied as a physiological aspect, overlooking the subjective perceptions of community-dwelling older adults, which holds global significance. This study aims to explore frailty perceptions among community-dwelling older adults, comparing those enrolled in a geriatric welfare program facility to those not-enrolled. METHODS: A cross-sectional design with a qualitative descriptive framework was employed, using focus group methodology. The study took place in rural West Bengal, located in eastern India, with a sample of 27 participants aged 60-87 years. Data collection occurred between October 2018 and January 2020, conducted through a face-to-face, semistructured discussion guide. Thematic analysis was performed to ensure data saturation and reliability. RESULTS: Three key themes emerged from the analysis: (a) Perceptions of frailty were associated with aging, functional dependence, and psychosocial health, (b) Exposure to a scientific definition led to an ideological dilemma influenced by personal experiences, (c) Walking speed and grip strength were prominent components of frailty. The findings revealed that there was no difference in perception between program-enrolled and nonenrolled older adults, likely due to the concept of frailty being new to all participants. However, it was noteworthy that participants enrolled in the welfare program exhibited a resilient mindset toward the definition and demonstrated a proactive interest in preserving their overall health. DISCUSSION: This novel study underscores the necessity of enhancing community awareness and integrating frailty management into the Indian health care system, which is yet to be fully integrated, aiming to promote the well-being of older adults.

Imaging bioluminescence by detecting localized haemodynamic contrast from photosensitized vasculature.

Bioluminescent probes are widely used to monitor biomedically relevant processes and cellular targets in living animals. However, the absorption and scattering of visible light by tissue drastically limit the depth and resolution of the detection of luminescence. Here we show that bioluminescent sources can be detected with magnetic resonance imaging by leveraging the light-mediated activation of vascular cells expressing a photosensitive bacterial enzyme that causes the conversion of bioluminescent emission into local changes in haemodynamic contrast. In the brains of rats with photosensitized vasculature, we used magnetic resonance imaging to volumetrically map bioluminescent xenografts and cell populations virally transduced to express luciferase. Detecting bioluminescence-induced haemodynamic signals from photosensitized vasculature will extend the applications of bioluminescent probes.

Gender Differences in Determinants of the Components of the Frailty Phenotype among Older Adults in India: Findings from LASI Wave-1.

This study examines the gender-specific determinants of the components of frailty in a community-dwelling setting in India. Using data from the Longitudinal Ageing Study in India (LASI) Wave-1, this study employed 30,978 (14,885 male and 16,093 female) older adults (aged 60+) to fulfil the study objective. The modified Fried frailty phenotype criteria defines frailty by the five components: exhaustion, weak grip strength, slow walking speed, unintentional weight loss, and low physical activity. The result showed grip strength (79.1%) as the most discriminant component among males, and physical activity (81.6%) as the most discriminant component among females. The results also indicated that grip strength (male: 98.0%, female: 93.5%) and physical activity (male: 94.8%, female: 96.9%) showed a sensitivity of more than 90%, which appears to be a good indicator of frailty. Combining this dual marker increased the accuracy to 99.97% among male and 99.98% among female samples. The findings suggested adding grip strength and physical activity as a proxy measure of frailty, which can increase the precision of screening without a large additional investment of time, training, or cost.

Cognitive frailty among community-dwelling rural elderly population of West Bengal in India.

OBJECTIVES: There has been growing interest in the links between physical frailty and cognitive impairment: both can increase the risk of emerging life-threatening health problems and are currently prominent within the global geriatric health agenda. A recent consensus proposes the idea of 'cognitive frailty' defined by the presence of both physical frailty and cognitive impairment in the absence of dementia. Present study is intended to determine the prevalence of cognitive frailty and its associated factors. METHODS: Cross-sectional survey was conducted among the rural community-dwelling elderly population of West Bengal, India (n = 510), without diagnosed dementia at baseline. An Interview-based questionnaire was administered to obtain information on sociodemographic, physical and psychosocial characteristics. Study participants were categorized as non-cognitive impairment (NCI) and cognitive impairment (CI) by Bangla Adaptation of Mini-Mental State Exam (BMSE ≤ 25) scale, as non-physical frailty (NPF) and physical frailty (PF) using Modified Fried Frailty Phenotype (FP ≥ 3) scale, as robust (NPF + NCI), pre-cognitive frailty (NPF + CI or PF + NCI) and cognitive frailty (PF + CI). RESULTS: The overall prevalence of cognitive frailty was 21.8%. In multinomial regression analysis, final model indicated that increasing age, being woman, out-of-wedlock, poor education and non-working sociodemographic status had significant association with cognitive frailty. Poor nutritional status, low health-related quality of life and depression are also prone among the cognitively frail participants. CONCLUSIONS: Present study allows us to understand complementary relationships between sociodemographic, physical, psychosocial characteristics and cognitive frailty. There is a dire need for multidimensional approach for providing appropriate and comprehensive geriatric health care for developing countries like India.

Stereoselective total synthesis of (-)-hygrophorone A12 and 4-epi-2,3-dihydrohygrophorone H12.

Stereoselective total synthesis of anti-fungal cyclopentenone (-)-hygrophorone A12 and cyclopentanone 4-epi-2,3-dihydrohygrophorone H12 were achieved in high overall yields from d-ribose. An aqueous KOH mediated diastereoselective formation of ß-hydroxy ketone with three contiguous chiral centres served as a key step in this synthesis.

Spatio-Temporal Autophagy Tracking with a Cell-Permeable, Water-Soluble, Peptide-Based, Autophagic Vesicle-Targeted Sensor.

Autophagy is an essential cellular degradation process. Impaired autophagy has been linked to multiple disorders, including cancer and neurodegeneration. Tracking the autophagic flux in living cells will provide mechanistic insights into autophagy and will allow rapid screening of autophagy modulators as potential therapeutics. Imaging autophagy to track the autophagic flux demands a cell-permeable probe that can specifically target autophagic vesicles and report on the extent of autophagy. Existing fluorescent protein-based probes for imaging autophagy target autophagic vesicles but are cell-impermeable and degrade with the progress of autophagy resulting in ambiguous information on the later stages of autophagy. Although small-molecule-based autophagy probes can be cell-permeable, they are mostly water-insoluble and often target lysosomes instead of autophagic vesicles leading to incomplete evidence of the early stages of the process. Hence, there is a major gap in the ability to link the imaging data obtained by applying fluorescent sensors to the real extent of autophagy in living cells. To address these challenges, we have combined the desirable features of targetability and cell permeability to develop a novel water-soluble, cell-permeable, visible-light excitable, peptide-based, fluorescent sensor, HCFP, for imaging autophagy and tracking the autophagic flux. The probe readily enters living cells within 30 min of incubation, distinctly targets autophagic vesicles, and spatio-temporally tracks the entire autophagy pathway in living cells via a ratiometric pH-sensitive detection scheme. The salient features of the probe combining targetability with cell permeability should provide an edge in high-throughput screening of autophagy modulators by tracking autophagy live.

COVID-19 lockdown impacts on heavy metals and microbes in shallow groundwater and expected health risks in an industrial city of South India.

In this investigation, the positive impact of COVID-19 lockdown on heavy metals concentration and biological parameters in the shallow groundwater samples of Coimbatore city of South India was ascertained. The groundwater samples (n=15) were obtained from shallow open wells during before lockdown (24-25 February 2020) and after lockdown (2-3 June 2020) periods. These samples were analysed for heavy metals (Fe, Mn, Ni, Cr and Pb) and biological parameters (E. coli, Fecal coliforms, Fecal streptococci and Total coliforms). Fe concentration was within the permissible limit but, the concentrations of Mn, Ni, Cr and Pb were above the allowable limits for drinking uses as per the WHO. However, after lockdown the number of samples crossing the cutoff limit had considerably decreased (Mn: from 2 to 0 mg/L; Ni: from 13 to 10 mg/L; Cr: 7 to 5 mg/L and Pb: from 13 to 8 mg/L). The heavy metal pollution index (HPI) revealed that 176.75 km2 (67.4%) and 85.35 km2 (32.6%) areas fell under unsuitable and very poor categories, respectively, during the pre-lockdown period, whereas 138.23 km2 (52.6%), 118.98 km2 (45.3%) and 4.89 km2 (2.1%) areas fell under very poor, poor and good categories, respectively, during the post-lockdown period. Similarly, Total coliform, Fecal coliform and E. coli had decreased distinctly due to the pandemic lockdown. Therefore, the shutdown of small and large-scale industries during the lockdown period had improved the groundwater quality. The health risk assessment showed that 93%, 87% and 80% of pre-lockdown samples, and 87%, 80% and 73% of post-lockdown samples possessed non-carcinogenic risks (HI > 1) for children, female and male categories, respectively.