Nitrate and nitrogen oxides: sources, health effects and their remediation

Increased use of nitrogenous (N) fertilizers in agriculture has significantly altered the global N-cycle because they release nitrogenous gases of environmental concerns. The emission of nitrous oxide (N2O) contributes to the global greenhouse gas accumulation and the stratospheric ozone depletion. In addition, it causes nitrate leaching problem deteriorating ground water quality. The nitrate toxicity has been reported in a number of studies showing the health hazards like methemoglobinemia in infants and is a potent cause of cancer. Despite these evident negative environmental as well as health impacts, consumption of N fertilizer cannot be reduced in view of the food security for the teeming growing world population. Various agronomic and genetic modifications have been practiced to tackle this problem. Some agronomic techniques adopted include split application of N, use of slow-release fertilizers, nitrification inhibitors and encouraging the use of organic manure over chemical fertilizers. As a matter of fact, the use of chemical means to remediate nitrate from the environment is very difficult and costly. Particularly, removal of nitrate from water is difficult task because it is chemically non-reactive in dilute aqueous solutions. Hence, the use of biological means for nitrate remediation offers a promising strategy to minimize the ill effects of nitrates and nitrites. One of the important goals to reduce N-fertilizer application can be effectively achieved by choosing N-efficient genotypes. This will ensure the optimum uptake of applied N in a balanced manner and exploring the molecular mechanisms for their uptake as well as metabolism in assimilatory pathways. The objectives of this paper are to evaluate the interrelations which exist in the terrestrial ecosystems between the plant type and characteristics of nutrient uptake and analyze the global consumption and demand for fertilizer nitrogen in relation to cereal production, evaluate the various methods used to determine nitrogen use efficincy (NUE), determine NUE for the major cereals grown across large agroclimatic regions, determine the key factors that control NUE, and finally analyze various strategies available to improve the use efficiency of fertilizer nitrogen

Insect pest resistance: an alternative approach for crop protection

From experience with insect resistance caused by synthetic chemical insecticides, it is clear that no single management tactic can provide lasting solutions to the insect pest problem. Biological control is a component of integrated pest management strategies that minimize insecticide spray applications and move towards ecofriendly systems of pest management. Successful utilization of host plant resistance, phytochemical products, pheromones, biological control agents such as predators, parasitoids, entomopathogenic bacteria, virus, nematodes, and fungi can help to control many destructive pests to achieve sustainable crop protection

HEPATOPROTECTIVE EFFECTS OF PUNICA GRANATUM FRUIT AGAINST D-GALACTOSAMINE INDUCED HEPATOTOXICITY IN RATS: IN VITRO AND IN VIVO STUDIES

Objective: Hepatoprotective activity of Punica granatum Linn. (Family: Punicaceae) was evaluated by in vitro and in vivo model. HepG2 cell lines were used for in vitro study and D-Galactosamine (D-GalN) induced hepatic damage model for in vivo evaluation.Methods: Hepatoprotective potential was assessed by measuring serum level of glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, alkaline phosphatase, total bilirubin, and albumin. Enzymatic antioxidant parameters like TBARs (thiobarbituric acid reactive substances), GSH (glutathione), SOD (superoxide dismutase) and CAT (catalase) also evaluated in this study. Results: Rats treated with D-GalN showed a significant increase in serum levels of SGOT (serum glutamate oxaloacetate transaminase), SGPT (serum glutamate pyruvate transaminase), ALP (alkaline phosphatase), bilirubin and TBARs, reflecting liver damage. The in vitro study indicates a beneficial effect of aqueous extract of P. granatum in comparison with methanolic extract, on D-GalN induced toxicity to HepG2 cells. On the basis of in vitro study, aqueous extract was selected for in vivo evaluation. The aqueous extract of P. granatum significantly reduced the elevated serum biomarkers, indicating the recovery of hepatocellular injury. It was also observed that D-GalN induced a significant decrease in GSH, SOD, CAT, protein, and albumin level were increased on the treatment of the rats with aqueous extract of P. granatum. The findings were also confirmed by histopathological studies. Periportal area and extensive hepatocyte damage and haemorrhage are seen in D-GalN treated group. The portal triad with less degree of inflammatory cell infiltration around the bile duct is seen in P. granatum (500 mg/kg)+(D-GalN) treated group.Conclusion: Results of this study revealed that P. granatum fruit could afford a significant protection for the alleviation of hepatic toxicity. Possible mechanism may involve its action against oxidative stress.Â

Agricultural adaptation and climate change policy for crop production in Africa

Africa is considered among the most highly vulnerable regions to climate change because of extremes of drought, flooding, inappropriate land tenure systems, overdependence on rainfed agriculture, and widespread poverty. The impact of climate change is moderated by several factors such as access to land, inputs, credit, and markets. Thus, there is a critical need for decision makers at different levels in Africa to develop matching response strategies and policies to reduce vulnerability and foster resilient livelihood systems on a sustainable basis. The smallholder farming communities are inherently the most vulnerable to the negative impacts of climate change, and are always away from the advantage of any emerging opportunities due to resource constraints. About 65 % of national agricultural earnings in this continent is derived from the crop production of staple cereals, particularly maize. Due to shrinkage in cultivated area, production is also about 5–25 %, and the region’s need is more chronic for food and feed. The climate change challenge is aggravated by diminishing soil productivity and the decline in natural resources has affected the livelihood of rural and peri-urban communities. The communities have drawn on their indigenous knowledge systems with the support of local institutions and traditional social safety nets to adopt the various multiple stress factors related to climate change and variability. However, there is still limited empirical evidence on the robustness of these systems in support of social collaborations and resolving conflicts arising from the resource scarcity in the wake of climate change. Comprehensive policy frameworks are therefore required to expand the climate change adaptation horizons beyond the boundaries of current farming systems. For instance, the risk of crop-based enterprises has increased by deteriorating climatic conditions. There is much evidence of multiple stresses characterising the existing poverty traps for the predominantly rural communities, and challenges of chronic food insecurity, but no evidence on how current agriculture and climate change policy frameworks are able to address these multiple stress factors against the increasing risk and uncertainty of agriculture as a source of climate change adaptation. Currently, the majority of the farmers lives beyond the reach of markets, yet agricultural development policies are hinged on the principles of market participation. Transformation of these subsistence farms into commercially oriented and market-driven production systems will effectively call for structural and process changes in knowledge systems, technology development and delivery, institutions, and policies. The empirical research shows evidence of current and future impacts of climate change and variability on agricultural production systems, and their implications on the resilience of smallholder farming systems currently supporting the poorer and more vulnerable communities. Over the past decade, there has been a remarkable increase in awareness about climate change issues with diverse stakeholders, including policy makers. The lack of knowledge on the nature, magnitude, and direction of impacts at the indigenous community and national scales will likely continue to haunt decision-making processes regarding the development of robust strategies and policies to support adaptation. However, the regional agricultural sector has to undergo major transformation processes in order to meet emerging demands for adaptation. This may entail changes in the types and forms of information, knowledge, technologies, resource regimes, and institutions driving current production systems. There are still major knowledge gaps across disciplines on how local-level changes in climatic factors influence the socioecological processes that underpin agricultural production systems across spatial and temporal scales. Thus, it has been concluded that the policy making on climate change in Africa is not necessarily constrained by the lack of empirical evidence, but instead by the failure of policy makers to use available empirical evidence. The current failures in linking research to policy could be a major barrier to further research and development innovations for climate change adaptation. Evidence from limited climate change adaptation studies conducted with communities in the region revealed the importance of policy dialogue platforms as an integral part of research and development initiatives

Plant and necrotrophic fungal pathogen interaction: mechanism and mode of action

Necrotrophic fungal pathogens cause major losses to fruit, vegetable, and cereal crops annually and the economic impact is more than that of diseases caused by biotrophic pathogens. These pathogens are devastating because they kill as they colonize through production of cell wall-degrading enzymes and phytotoxins, obtaining nutrients for growth and reproduction from the dead plant cells. They explore a wide variety of virulence strategies and based on these the pathogens are classified into host-specific and broad host-range necrotrophs. Plants are equipped with an immune system as a defense mechanism while the necrotrophic fungal pathogenic arsenal suppresses the immune responses for disease manifestation. Plant defense response involves the interplay of signaling molecules which include various phytohormones like jasmonic acid, ethylene, salicylic and abscisic acid which also serve as regulators of the immune response. Coordination at the transcriptional level of genes for the production of defense molecules including antimicrobial phytoalexins and pathogenesis-related proteins by transcription factors such as WRKY33 and ERF which are responsive to the signaling molecules has been observed. The roles for several important transcription factors already unveiled through studies of mutants in the model plant, Arabidopsis thaliana and some of the information translatable to crop plants. The present chapter shows the interconnection between cell wall integrity and the action of signaling molecules in the expression of defense-related genes. Moreover, the epigenetic mechanism through DNA and histone modification is also discussed

An insight into biotechnological approaches used for the improvement of secondary metabolites from the medicinal aquatic plant, water hyssop (Bacopa monnieri L.)

Water has a significant role on human civilizations by providing food and water along with plants grown on the banks or within the water bodies. Aquatic plants or semiaquatic plants are the group of plants that love to live in or near water bodies, and some of these plants are economically important due to their usage as food or medicinal plants. Water hyssop or brahmi (Bacopa monnieri L.) is one of the important semiaquatic/aquatic plants that has been used for medicinal purposes since ancient time in Indian subcontinent. The plant contains several secondary metabolites like bacosides which are used as memory enhancer tonic commercially. Brahmi-based registered drugs are available in India and other countries as memory enhancer tonic and for other diseases like Alzheimer’s disease, anxiety, asthma, stomach ulcers, and respiratory ailments and for curing chronic diseases like cancer. Bacopa is facing the threat of extinction from wild as it is not a cultivated plant and propagation through seed is limited due to low availability of and viability of seeds. On the other hand, extensive works on the propagation of this important medicinal plant has been reported to develop in vitro protocols for its conservation and plant propagation for secondary metabolite production. Different in vitro techniques like cell suspension culture, callus culture, and organogenesis have been reported with the objective of producing or enhancing bacoside. Furthermore, application of other biotechnological approaches like Agrobacteriummediated genetic transformation studies, use of mutagens, and in vitro polyploidization have also been reported. Thus, the aim of this chapter is to highlight the application of different biotechnological approaches used for the production, conservation, and secondary metabolite production of B. monnieri. © Springer Nature Singapore Pte Ltd. 2019

Biocontrol of plant parasitic nematodes by fungi: efficacy and control strategies

Increasing knowledge and growing concern about the elevated cost of inorganic fertilizers or chemical pesticides with their vast applications on various crop plants has raised interest in the alternative method of plant disease protection caused by plant parasitic nematodes. These alternative methods are not only cost-effective but also eco-friendly to the environment and human health. Among the various rhizospheric microorganisms, opportunistic fungi like Paecilomyces lilacinus, Pochonia chlamydosporia, and arbuscular mycorrhizal (AM) fungi have the potential to reduce the severity of diseases caused by plant parasitic nematodes and also improved the plant growth and biomass production. This chapter provides an overview on the biocontrol potential of opportunistic as well as AM fungi on the growth and development of various crop plants. The details about the interactions between these fungi and plant parasitic nematodes have been discussed. An overview of the recent cost-effective technologies used for the mass propagation of these beneficial rhizospheric microorganisms is also discussed

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

Background: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. Methods: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. Findings: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. Interpretation: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

BACKGROUND: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. METHODS: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. FINDINGS: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. INTERPRETATION: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic. FUNDING: Bill & Melinda Gates Foundation