Natural-Product-Inspired Microwave-Assisted Synthesis of Novel Spirooxindoles as Antileishmanial Agents: Synthesis, Stereochemical Assignment, Bioevaluation, SAR, and Molecular Docking Studies.

Leishmaniasis is a neglected tropical disease, and there is an emerging need for the development of effective drugs to treat it. To identify novel compounds with antileishmanial properties, a novel series of functionalized spiro[indoline-3,2'-pyrrolidin]-2-one/spiro[indoline-3,3'-pyrrolizin]-2-one 23a-f, 24a-f, and 25a-g were prepared from natural-product-inspired pharmaceutically privileged bioactive sub-structures, i.e., isatins 20a-h, various substituted chalcones 21a-f, and 22a-c amino acids, via 1,3-dipolar cycloaddition reactions in MeOH at 80 °C using a microwave-assisted approach. Compared to traditional methods, microwave-assisted synthesis produces higher yields and better quality, and it takes less time. We report here the in vitro antileishmanial activity against Leishmania donovani and SAR studies. The analogues 24a, 24e, 24f, and 25d were found to be the most active compounds of the series and showed IC50 values of 2.43 µM, 0.96 µM, 1.62 µM, and 3.55 µM, respectively, compared to the standard reference drug Amphotericin B (IC50 = 0.060 µM). All compounds were assessed for Leishmania DNA topoisomerase type IB inhibition activity using the standard drug Camptothecin, and 24a, 24e, 24f, and 25d showed potential results. In order to further validate the experimental results and gain a deeper understanding of the binding manner of such compounds, molecular docking studies were also performed. The stereochemistry of the novel functionalized spirooxindole derivatives was confirmed by single-crystal X-ray crystallography studies.

Irrigation Effect on Yield, Skin Blemishes, Phellem Formation, and Total Phenolics of Red Potatoes.

Dark Red Norland is an important potato cultivar in the fresh market due to its attractive bright, red colour, and good yield. However, skin blemishes such as silver patch, surface cracking, and russeting can negatively influence the tuber skin quality and marketability. It is well known that potato is a drought-sensitive plant. This study was conducted to determine whether irrigation would affect Dark Red Norland's yield and skin quality. A three-year field trial was conducted by Peak of the Market in Manitoba, Canada. Plants were treated under both irrigation and rainfed conditions. The results show that irrigation increased the total yield by 20.6% and reduced the severity of surface cracking by 48.5%. Microscopy imaging analysis demonstrated that tubers from the rainfed trials formed higher numbers of suberized cell layers than those of the irrigated potatoes, with a difference of 0.360 to 0.652 layers in normal skins. Surface cracking and silver patch skins had more suberized cell layers than the normal skins, with ranges of 7.805 to 8.333 and 7.740 to 8.496, respectively. A significantly higher amount of total polyphenols was found in the irrigated samples with a mean of 77.30 mg gallic acid equivalents (GAE)/100 g fresh weight (fw) than that of the rainfed samples (69.80 mg GAE/100 g fw). The outcome of this study provides a better understanding of the water regime effect causing these skin blemishes, which could potentially be used to establish strategies to improve tuber skin quality and minimize market losses.

Molecular and morphological identification of frog species collected at Rara Lake in Rara National Park, Nepal.

This study seeks to clarify the taxonomic identity of three adult frogs and two tadpoles from Rara Lake situated in Rara National Park, Mugu district, Western Nepal, using both phenotypic and mitochondrial sequence data (16S rRNA gene). Based on the molecular data, we determined our specimens belonged to two species; Paa cf. ercepeae (Dubois, 1974) and Paa rarica (Dubois, Matsui, and Ohler, 2001), and this assignment is also supported by morphology. Principal component analysis of phenotypic data clustered species into large-bodied (SVL > 55 mm) and small-bodied (SVL < 55 mm) groups. The molecular data suggest that Paa rarica belonged to a group that contains several undescribed lineages and that Paa liebigii (Gnther, 1860) hosts extensive cryptic diversity. Our study also documents that Paa species in the Himalayan region are more widely distributed than previously believed.

Thrombosis and thromboembolism: Brighton collaboration case definition and guidelines for data collection, analysis, and presentation of immunization safety data.

This is a Brighton Collaboration case definition of thrombosis and thromboembolism to be used in the evaluation of adverse events following immunization, and for epidemiologic studies for the assessment of background incidence or hypothesis testing. The case definition was developed by a group of experts convened by the Coalition for Epidemic Preparedness Innovations (CEPI) in the context of active development of SARS-CoV-2 vaccines. The case definition format of the Brighton Collaboration was followed to develop a consensus definition and defined levels of certainty, after an exhaustive review of the literature and expert consultation. The document underwent peer review by the Brighton Collaboration Network and by selected expert reviewers prior to submission.

Unwelcome prevalence of leishmaniasis with several other infectious diseases.

Co-infection among leishmaniasis and other infectious diseases is common among natural populations especially in the endemic areas of the disease. It depends on the environmental factors, vector availability, host-parasite interactions and above all geographical boundaries. Leishmaniasis being an immunosuppressive disease empowers the invading opportunistic infections to invade and successfully colonize. A variety of infections coexist with leishmaniasis like HIV, leprosy, tuberculosis, schistosomiasis etc. With the different pathology and immune status, co-infection in most cases leads to disease severity and increased mortality.Inevitably, co-infection increases the complexity and poses a threat in the cure and control programmes. This is the first review which highlights the existing co-infections of leishmaniasis with other infectious diseases. The review also focuses on the immunology of co-infections together, diagnosis and the treatment options available for treating such cases. With the changing environment and the overlapping endemic areas of leishmaniasis with other diseases, it becomes difficult to treat a disease without accurate diagnosis. Thus, the review insists on the need for more research on development of newer and differential diagnostic methods for co-infected individuals with theoverlapping symptoms.

Oxidant-Switched Palladium-Catalyzed Regioselective Mono- versus Bis-ortho-Aroylation of 1-Aryl-1H-indazoles with Aldehydes via C-H Bond Activation.

A highly efficient oxidant-switched palladium-catalyzed regioselective C(sp2)-H/C(sp2)-H cross-dehydrogenative coupling (CDC) for direct mono/bis-ortho-aroylation of substituted 1-phenyl-1H-indazoles 1a-j with various substituted aldehydes 3a-t via C(sp2)-H bond activation has been developed. In this study, Pd-catalyzed chelation-assisted mono- or bis-aroylation of substituted 1-phenyl-1H-indazoles depends on the type of oxidant being used for the CDC reaction. While mono-ortho-aroylation of substituted 1-phenyl-1H-indazole was obtained using dicumylperoxide (DCP) as the oxidant, the bis-ortho-aroylation product has been afforded by the use of tert-butyl hydroperoxide (TBHP). Regardless of the greater activity at the C-3 position of 1H-indazoles, the greater coordinating capacity of the N atom directed the aroylating group to the ortho position, leaving behind the nondirected metalation pathway. The Pd-catalyzed operationally simplified methodology proceeded in the presence of oxidants with either DCP or TBHP in dichloroethane as the solvent at 110 °C for 16 h, which generated a miscellaneous variety of monosubstituted o-benzoyl/acyl-1-aryl-1H-indazoles 4a-t/5a-i and bis-substituted o-benzoyl-1-aryl-1H-indazoles 6a-j in ≤88% yields. The probable mechanistic pathway involves a free radical chelation-assisted approach that could be accomplished by the addition of an in situ-generated oxidant-promoted benzoyl/acyl radical to the ortho position of 1-phenyl-1H-indazoles. A wide range of substrates, a high functional group tolerance, gram-scale synthesis, control/competitive experiments, and a variety of synthetic applications further exemplify the versatility of the developed methodology.

Outcomes of Ayurvedic care in a COVID-19 patient with hypoxia - A case report.

This paper reports for the first time, the outcomes of Ayurvedic intervention in a COVID-19 patient with hypoxia requiring supportive oxygen therapy. Patient developed fever, severe cough, loss of smell, loss of taste, nasal block, anorexia, headache, body ache, chills, and fatigue and was hospitalised when she developed severe breathing difficulty. Later, she tested positive for COVID-19 by RT-PCR. The patient sought Ayurvedic treatment voluntarily when her SPO2 remained at 80% even after being given oxygen support. The patient was administered Ayurvedic medicines while undergoing oxygen therapy at the hospital. The patient refused to take Fabiflu recommended by the treating physician and discontinued other Allopathic drugs except for Vitamin C. The patient showed clinical improvement within a day of administration of Ayurvedic medicines and was able to talk, eat, and sit on the bed without breathing difficulty and her SPO2 became stable between 95 and 98%. In the next two days, she was asymptomatic without oxygen support and was discharged from the hospital in the following week. Since obesity and high plasma C-Reactive Protein (CRP) levels indicated high risk for progression to severe disease, the favourable outcomes with Ayurvedic treatment in this patient is significant and warrants further studies. Ayurvedic care may be considered as a first-line cost-effective alternative for COVID-19 patients presenting with symptomatic hypoxia in an integrative setup.

Ayurvedic management of persistent hypoxia in a diabetic and hypertensive COVID-19 patient in the post-hospitalization period-A case report.

COVID-19 patients may require supplemental oxygen therapy at home after recovery from COVID-19. We report benefits of add on Ayurvedic intervention in a 75-year-old gentleman who was oxygen dependent post hospitalisation. He was earlier treated for COVID-19 related bilateral pneumonitis, Acute Respiratory Distress Syndrome and Acute Renal Failure. Patient reported breathing difficulty, generalized weakness, reduced appetite and severe constipation. The Pulse Oximetry readings with oxygen support fluctuated between 80 and 85 %, Blood Pressure was 150/100 mm Hg, LDH raised at 463 IU/L and HbA1c at 8.7%. The patient was administered micro-doses of Rasasindura sublingually every 10 min for one day followed by administration of Indukanta Ghrita and Suvarnamalinivasanta Rasa. The oxygen saturation improved to 95 % in 12 hrs of initiating treatment, oxygen support was weaned off on the third day of starting the Ayurvedic treatment, three weeks earlier than prescribed at the time of discharge. The patient is ambulant and maintaining oxygen saturation between 95 and 98 %. This case report highlights the potential of Ayurvedic intervention to manage patients with persistent hypoxia in post hospitalization phase. Well-designed studies are warranted to confirm the benefits of integrating such interventions with standard of care in COVID-19.

Evidence for Reversal of Immunosuppression by Homeopathic Medicine to a Predominant Th1-type Immune Response in BALB/c Mice Infected with Leishmania donovani.

BACKGROUND: Visceral leishmaniasis (VL) is a neglected tropical disease that is fatal if treatment is not given. The available chemotherapeutic options are unsatisfactory, and so complementary therapies like homeopathy might be a promising approach. METHODS: A nosode from a pure axenic culture of Leishmania donovani was prepared and screened for its anti-leishmanial potential both in an in-vitro and an in-vivo experimental approach. RESULTS: Leishmania donovani amastigote promastigote nosode (LdAPN 30C) exhibited significant anti-leishmanial activity against the promastigote forms of Leishmania donovani and was found to be safe. A study conducted on VL-infected mice revealed that LdAPN 30C resolved the disease by modulating the host immune response toward the Th1 type through upregulating the pro-inflammatory cytokines (IFN-γ and IL-17) and inducing nitric oxide (NO) levels in the infected macrophages. The hepatic parasite load was also found to be significantly decreased. The nosode was found to be safe, as no histological alterations in the liver or kidney were observed in the animals treated with the LdAPN 30C. CONCLUSION: This is the first study in which an axenic culture of Leishmania donovani has been used for the preparation of a homeopathic medication. The study highlights the anti-leishmanial and immunomodulatory potential of a homeopathic nosode in experimental VL.

Over-the-Counter Sale of Antibiotics in India: A Qualitative Study of Providers' Perspectives across Two States.

India has one of the highest rates of antimicrobial resistance (AMR) worldwide. Despite being prescription drugs, antibiotics are commonly available over-the-counter (OTC) at retail pharmacies. We aimed to gain insight into the OTC sale of antibiotics at retail pharmacies and to elucidate its underlying drivers. We conducted face-to-face, in-depth interviews using convenience sampling with 22 pharmacists and 14 informal dispensers from 36 retail pharmacies across two Indian states (Haryana and Telangana). Thematic analysis revealed that antibiotics were often dispensed OTC for conditions e.g., fever, cough and cold, and acute diarrhea, which are typically viral and self-limiting. Both Access and Watch groups of antibiotics were dispensed for 1-2 days. Respondents had poor knowledge regarding AMR and shifted the blame for OTC practices for antibiotics onto the government, prescribers, informal providers, cross practice by alternative medicine practitioners, and consumer demand. Pharmacists suggested the main drivers for underlying OTC dispensing were commercial interests, poor access to public healthcare, economic and time constraints among consumers, lack of stringent regulations, and scanty inspections. Therefore, a comprehensive strategy which is well aligned with activities under the National Action Plan-AMR, including stewardship efforts targeting pharmacists and evidence-based targeted awareness campaigns for all stakeholders, is required to curb the inappropriate use of antibiotics.

Phylogeographical analysis shows the need to protect the wild yaks' last refuge in Nepal.

The wild yak Bos mutus was believed to be regionally extinct in Nepal for decades until our team documented two individuals from Upper Humla, north-western Nepal, in 2014. The International Union for Conservation of Nature (IUCN) seeks further evidence for the conclusive confirmation of that sighting. We conducted line transects and opportunistic sign surveys in the potential wild yak habitats of Humla, Dolpa, and Mustang districts between 2015 and 2017 and collected genetic samples (present and historic) of wild and domestic yaks Bos grunniens. We also sighted another wild yak in Upper Humla in 2015. Phylogenetic and haplotype network analyses based on mitochondrial D-loop sequences (~450 bp) revealed that wild yaks in Humla share the haplotype with wild yaks from the north-western region of the Qinghai-Tibetan Plateau in China. While hybridization with domestic yaks is a major long-term threat, illegal hunting for meat and trophy put the very small populations of wild yaks in Nepal at risk. Our study indicates that the unprotected habitat of Upper Humla is the last refuge for wild yaks in Nepal. We recommend wild yak conservation efforts in the country to focus on Upper Humla by (i) assigning a formal status of protected area to the region, (ii) raising awareness in the local communities for wild yak conservation, and (iii) providing support for adaptation of herding practice and pastureland use to ensure the viability of the population.

Over-the-counter sale of antibiotics - Using Net-Map to identify and segment stakeholders as the first step towards the development of smart regulation.

INTRODUCTION: Antimicrobial resistance (AMR) is a complex public health problem requiring coordinated efforts by a multitude of public and private sector stakeholders. Over-the-counter (OTC) antibiotics sale is contributing to rising AMR. We applied NetMap, a research tool to identify, prioritize and assess relationships among stakeholders, also to identify the stakeholders that must be engaged for regulating antibiotic OTC sale for humans in India. METHODS: Through a one-day workshop, a team of expert facilitators engaged with a mixed group of stakeholders-regulators, drug manufacturers, retailers and consumers of antibiotics to identify and rank stakeholders based on their role, power/interest and influence. Stakeholders were listed and grouped as per the type of agency represented. Carrom discs were stacked against each stakeholder with the height of stack reflecting perceived power. RESULTS: A total of 25 stakeholders were identified from government, non-government, private/corporate, academic and research agencies and the general public. Based on the stacking exercise, a power/interest matrix was developed with six stakeholders having high power and high interest, five having high power but low interest, six having low power but high interest and eight having low power. A visual NetMap was developed to position the stakeholders as proximal, middle and distal based on their perceived influence. CONCLUSIONS: NetMap can be used with stakeholders with varying skill sets. It is a useful project initiation tool that was successfully used to prioritize stakeholders for reaching out, for targeted outreach and development of customized tools for developing innovative regulation for tackling OTC sale of antibiotics. It also pre-empted any conflict of interests.

Pharmaceutical effluent: a critical link in the interconnected ecosystem promoting antimicrobial resistance.

Antimicrobial resistance (AMR) is a complex global health issue and will push twenty-four million people into extreme poverty by 2030, risking the sustainable development goals (SDGs) 2, 3, 6, 9, 12, and 17 if not addressed immediately. Humans, animals, and the environment are the reservoirs that contribute and allow AMR to propagate in interconnected ecosystems. The emergence of antibiotic-resistant bacteria and antibiotic-resistant genes in the water environment has become an important environmental health issue. One of the major influencers from environment sector is the pharmaceutical industry which is growing globally to meet the ever-increasing demand of antibiotics, especially in low- and middle-income countries. The pharmaceutical effluent has a mix of large concentrations of antibiotics and antibiotic resistance genes, and these sites act as hotspots for environmental contamination and the spread of AMR. Inadequate treatment of the effluent and its irresponsible disposal leads to unprecedented antibiotic contamination in the environment and their persistent presence in the environment significantly modulates the bacterial genomes' expression that is responsible for increase and spread of AMR. However, not much interventions are suggested in the National Action Plan developed on AMR by many countries. There are no regulations across the globe till date for the level of antibiotic residues in pharmaceutical effluent for the growing pharmaceutical industry. This review put together the work done showing several detrimental effects of the antimicrobial residues in the pharmaceutical effluent which leads to rise in development of AMR. The environment risk approach and need to have indicators to measure environment risk is a way forward for all countries engage in antibiotic manufacturing. Overall, efforts to address the problem are isolated and fragmented. Policymakers, regulators, manufacturers, researchers, civil society, and the community need to collaborate so that antibiotics are produced sustainably and continue to stay effective in treating bacterial infections.

Knowledge and behavior of consumers towards the non-prescription purchase of antibiotics: An insight from a qualitative study from New Delhi, India.

BACKGROUND: In Low-and Middle-Income Countries, including India, consumers often purchase antibiotics over-the-counter (OTC) from retail pharmacies. This practice leads to the inappropriate use of antibiotics in the community which is an important driver for the development of antimicrobial resistance. A better understanding of consumers' views towards this grave public health concern is critical to developing evidence-based intervention programs for awareness among the general population. OBJECTIVE: To explore knowledge, practice and, behavior of consumers towards antibiotics, antibiotic use, antimicrobial resistance, purchasing behavior of consumers for antibiotics, and to gain insight which will help in developing evidence-based policy interventions. METHODS: 72 in-depth consumer interviews were conducted in all 11 districts of the National Capital Territory of Delhi. The qualitative data were analyzed using thematic analysis. RESULTS: Our study found that retail pharmacies were the first point of consultation for common ailments for patients/consumers once home remedies failed; they were largely unaware of the threat of antimicrobial resistance. Consumers' knowledge of antibiotic use and about antimicrobial resistance was low, they used old prescriptions, and bought antibiotics OTC to save time and money. Despite the presence of regulations constituted to regulate the sale of antibiotics by the Government and the implementation of national campaigns, the practice of self-medication and behaviors such as OTC purchase, non-adherence to prescribed antibiotics was prevalent. Consumers perceive that antibiotics provide quick relief and accelerate the curing process and retail pharmacy shops try to protect their retail business interests by honoring old prescriptions and self-medication for antibiotics. CONCLUSIONS: The lack of awareness and insufficient knowledge about what antibiotics are and issues such as antimicrobial resistance or antibiotic resistance resulted in misuse of antibiotics by consumers. Limited access to public healthcare and affordability of private healthcare are factors that contribute towards the self-medication/OTC purchase of antibiotics. The regular misuse of antibiotics through irrational use reinforces the need for strong enactment of strategies like continuous community awareness campaigns. Mitigation efforts should focus upon educating consumers continuously and sustainably for the understanding of antibiotic misuse, antimicrobial resistance, and promote better compliance with regulations.

Correlations Between Facial Expressivity and Apathy in Elderly People With Neurocognitive Disorders: Exploratory Study.

BACKGROUND: Neurocognitive disorders are often accompanied by behavioral symptoms such as anxiety, depression, and/or apathy. These symptoms can occur very early in the disease progression and are often difficult to detect and quantify in nonspecialized clinical settings. OBJECTIVE: We focus in this study on apathy, one of the most common and debilitating neuropsychiatric symptoms in neurocognitive disorders. Specifically, we investigated whether facial expressivity extracted through computer vision software correlates with the severity of apathy symptoms in elderly subjects with neurocognitive disorders. METHODS: A total of 63 subjects (38 females and 25 males) with neurocognitive disorder participated in the study. Apathy was assessed using the Apathy Inventory (AI), a scale comprising 3 domains of apathy: loss of interest, loss of initiation, and emotional blunting. The higher the scale score, the more severe the apathy symptoms. Participants were asked to recall a positive and a negative event of their life, while their voice and face were recorded using a tablet device. Action units (AUs), which are basic facial movements, were extracted using OpenFace 2.0. A total of 17 AUs (intensity and presence) for each frame of the video were extracted in both positive and negative storytelling. Average intensity and frequency of AU activation were calculated for each participant in each video. Partial correlations (controlling for the level of depression and cognitive impairment) were performed between these indexes and AI subscales. RESULTS: Results showed that AU intensity and frequency were negatively correlated with apathy scale scores, in particular with the emotional blunting component. The more severe the apathy symptoms, the less expressivity in specific emotional and nonemotional AUs was displayed from participants while recalling an emotional event. Different AUs showed significant correlations depending on the sex of the participant and the task's valence (positive vs negative story), suggesting the importance of assessing male and female participants independently. CONCLUSIONS: Our study suggests the interest of employing computer vision-based facial analysis to quantify facial expressivity and assess the severity of apathy symptoms in subjects with neurocognitive disorders. This may represent a useful tool for a preliminary apathy assessment in nonspecialized settings and could be used to complement classical clinical scales. Future studies including larger samples should confirm the clinical relevance of this kind of instrument.

Knowledge and behavior of consumers towards the non-prescription purchase of antibiotics: an insight from a qualitative study from New Delhi, India

BACKGROUND: In Low-and Middle-Income Countries, including India, consumers often purchase antibiotics over-the-counter (OTC) from retail pharmacies. This practice leads to the inappropriate use of antibiotics in the community which is an important driver for the development of antimicrobial resistance. A better understanding of consumers' views towards this grave public health concern is critical to developing evidence-based intervention programs for awareness among the general population. OBJECTIVE: To explore knowledge, practice and, behavior of consumers towards antibiotics, antibiotic use, antimicrobial resistance, purchasing behavior of consumers for antibiotics, and to gain insight which will help in developing evidence-based policy interventions. METHODS: 72 in-depth consumer interviews were conducted in all 11 districts of the National Capital Territory of Delhi. The qualitative data were analyzed using thematic analysis. RESULTS: Our study found that retail pharmacies were the first point of consultation for common ailments for patients/consumers once home remedies failed; they were largely unaware of the threat of antimicrobial resistance. Consumers' knowledge of antibiotic use and about antimicrobial resistance was low, they used old prescriptions, and bought antibiotics OTC to save time and money. Despite the presence of regulations constituted to regulate the sale of antibiotics by the Government and the implementation of national campaigns, the practice of self-medication and behaviors such as OTC purchase, non-adherence to prescribed antibiotics was prevalent. Consumers perceive that antibiotics provide quick relief and accelerate the curing process and retail pharmacy shops try to protect their retail business interests by honoring old prescriptions and self-medication for antibiotics. CONCLUSIONS: The lack of awareness and insufficient knowledge about what antibiotics are and issues such as antimicrobial resistance or antibiotic resistance resulted in misuse of antibiotics by consumers. Limited access to public healthcare and affordability of private healthcare are factors that contribute towards the self-medication/OTC purchase of antibiotics. The regular misuse of antibiotics through irrational use reinforces the need for strong enactment of strategies like continuous community awareness campaigns. Mitigation efforts should focus upon educating consumers continuously and sustainably for the understanding of antibiotic misuse, antimicrobial resistance, and promote better compliance with regulations

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Associations between private vaccine and antimicrobial consumption across Indian states, 2009-2017.

Vaccines can reduce antibiotic use and, consequently, antimicrobial resistance by averting vaccine-preventable and secondary infections. We estimated the associations between private vaccine and antibiotic consumption across Indian states during 2009-2017 using monthly and annual consumption data from IQVIA and employed fixed-effects regression and the Arellano-Bond Generalized Method of Moments (GMM) model for panel data regression, which controlled for income and public sector vaccine use indicators obtained from other sources. In the annual data fixed-effects model, a 1% increase in private vaccine consumption per 1000 under-5 children was associated with a 0.22% increase in antibiotic consumption per 1000 people (P < 0.001). In the annual data GMM model, a 1% increase in private vaccine consumption per 1000 under-5 children was associated with a 0.2% increase in private antibiotic consumption (P < 0.001). In the monthly data GMM model, private vaccine consumption was negatively associated with antibiotic consumption when 32, 34, 35, and 44-47 months had elapsed after vaccine consumption, with a positive association with lags of fewer than 18 months. These results indicate vaccine-induced longer-term reductions in antibiotic use in India, similar to findings of studies from other low- and middle-income countries.

Effects of phosphite as a plant biostimulant on metabolism and stress response for better plant performance in Solanum tuberosum.

Food availability represents a major worldwide concern due to population growth, increased demand, and climate change. Therefore, it is imperative to identify compounds that can improve crop performance. Plant biostimulants have gained prominence because of their potentials to increase germination, productivity and quality of a wide range of horticultural and agronomic crops. Phosphite (Phi), an analog of orthophosphate, is an emerging biostimulant used in horticulture and agronomy. The aim of this study was to uncover the molecular mechanisms through which Phi acts as a biostimulant with potential effects of overall plant growth. Field and greenhouse experiments, using 4 potato cultivars, showed that following Phi applications, plant performance, including several physio-biochemical traits, crop productivity, and quality traits, were significantly improved. RNA sequencing of control and Phi-treated plants of cultivar Xingjia No. 2, at 0 h, 6 h, 24 h, 48 h, 72 h and 96 h after the Phi application for 24 h revealed extensive changes in the gene expression profiles. A total of 2856 differentially expressed genes were identified, suggesting that multiple pathways of primary and secondary metabolism, such as flavonoids biosynthesis, starch and sucrose metabolism, and phenylpropanoid biosynthesis, were strongly influenced by foliar applications of Phi. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analyses associated with defense responses revealed significant effects of Phi on a plethora of defense mechanisms. These results suggest that Phi acted as a biostimulant by priming the plants, that was, by triggering dynamic changes in gene expression and modulating metabolic fluxes in a way that allowed plants to perform better. Therefore, Phi usage has the potential to improve crop yield and health, alleviating the challenges posed by the need of feeding a growing world population, while minimizing the agricultural impact on human health and environment.