scholarly journals Mechanistic understanding of iron toxicity tolerance in contrasting rice varieties from Africa: 2. Root oxidation ability and oxidative stress control

2020 ◽  
Vol 47 (2) ◽  
pp. 145
Author(s):  
Dorothy A. Onyango ◽  
Fredrickson Entila ◽  
James Egdane ◽  
Myrish Pacleb ◽  
Meggy Lou Katimbang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Sub Saharan Africa ◽  
Rice Varieties ◽  
Excess Iron ◽  
Improvement Programs ◽  
Sub Saharan ◽  
Breeding Efficiency ◽  
Biochemical Analyses ◽  
Fe Toxicity ◽  
And Control

To enhance breeding efficiency for iron (Fe) toxicity tolerance and boost lowland rice production in sub-Saharan Africa, we have characterised the morphological, physiological and biochemical responses of contrasting rice varieties to excess iron. Here, we report the capacity of four varieties (CK801 and Suakoko8 (tolerant), Supa and IR64 (sensitive)) to oxidise iron in the rhizosphere and control iron-induced oxidative stress. The experiments were conducted in hydroponic conditions using modified Magnavaca nutrient solution and 300 ppm of ferrous iron (Fe2+) supplied in the form of FeSO4. Severe oxidative stress was observed in sensitive varieties as revealed by their high levels of lipid peroxidation. Histochemical and biochemical analyses showed that tolerant varieties exhibited a better development of the aerenchyma and greater oxygen release than the sensitive varieties in response to excess Fe. Both suberin and lignin deposits were observed in the root, stem and leaf tissues but with varying intensities depending on the variety. Under iron toxic conditions, tolerant varieties displayed increased superoxide dismutase (SOD), glutathione reductase (GR), peroxidase (POX) and ascorbate peroxidase (APX) activities in both the roots and shoots, whereas sensitive varieties showed increased APX and catalase (CAT) activities in the roots. This study had revealed also that Suakoko8 mainly uses root oxidation to exclude Fe2+ from its rhizosphere, and CK801 possesses a strong reactive oxygen species scavenging system, in addition to root oxidation ability. Key traits associated with these tolerance mechanisms such as a well-developed aerenchyma, radial oxygen loss restricted to the root cap as well as strong activation of antioxidative enzymes (SOD, GR, POX and APX) could be useful selection criteria in rice varietal improvement programs for enhanced Fe toxicity tolerance.

scholarly journals Closing Gender Gaps in Climate-Smart Agriculture through Strengthening Women Rice Seed Farmer’s Capacities and Access to Quality Stress-tolerant Seed in Benin

2021 ◽  
Vol 10 (3) ◽  
pp. 41
Author(s):  
Espérance Zossou ◽  
Afiavi R. Agboh-Noameshie ◽  
Alidou Assouma-Imorou
Keyword(s):  
Seed Production ◽  
Division Of Labour ◽  
Sub Saharan Africa ◽  
Rice Seed ◽  
Design Strategies ◽  
Rice Varieties ◽  
New Varieties ◽  
Sub Saharan ◽  
Smart Agriculture ◽  
And Control

Climate change and stress conditions (drought; submergence, salinity, iron toxicity, and cold) disproportionately affect the poorest and most disadvantaged rice farmers, forcing them deeper into poverty. Recent advances in genetics and breeding enable the development of rice varieties tolerant of these abiotic stresses and their cultivation can substantially contribute to poverty alleviation in unfavourable environments and for poor rice consumers globally. Through the program Stress-Tolerant Rice for Africa and South Asia (STRASA), fourteen new stress-tolerant varieties were released, produced and distributed in Sub-Saharan Africa to reach millions of poor farmers. However, ignoring women’s contributions to agriculture and particular in seed production and failing to design strategies to reach them with new varieties miss significant opportunities to reduce poverty. This study investigates on gender issues in rice seed production in Benin through a gender analysis of the division of labour, access and control of resources, livelihood, and constraints and opportunities faced. Both qualitative and quantitative data were collected with 29 women and 29 men seeds producers using both the Harvard Analytical and the Sustainable Livelihoods Frameworks. Data showed that women are central in rice seed production; but are marginalized in their access and control of resources. Given to women resources property rights as well as improving their control on resources will help them to be more performant as seed producers. These areas for action are important in designing and implementing activities in gender-responsive ways for sustainable Stress-Tolerant Rice seed multiplication, dissemination and out scaling in Africa.

scholarly journals An afebrile heartwater-like syndrome in goats

2013 ◽  
Vol 84 (1) ◽  
Author(s):  
Rhoda Leask ◽  
Kenneth P. Pettey ◽  
Gareth F. Bath
Keyword(s):  
Clinical Signs ◽  
Control Measures ◽  
Sub Saharan Africa ◽  
Limiting Factor ◽  
Febrile Reaction ◽  
Presumptive Diagnosis ◽  
Appropriate Treatment ◽  
Sub Saharan ◽  
Characteristic Features ◽  
And Control

Heartwater is a serious limiting factor for sheep and goat production in the major endemic area of sub-Saharan Africa and therefore most knowledge, research and control methods originate from this region. Whilst the usual or common clinical presentations can be used to make a presumptive diagnosis of heartwater with a good measure of confidence, this is not always the case, and animals suffering from heartwater may be misdiagnosed because their cases do not conform to the expected syndrome, signs and lesions. One aberrant form found occasionally in the Channel Island breeds of cattle and some goats is an afebrile heartwaterlike syndrome. The most constant and characteristic features of this heartwater-like syndrome comprise normal temperature, clinical signs associated with generalised oedema, and nervous signs, especially hypersensitivity. The presumption that the disease under investigation is the afebrile heartwater-like syndrome entails a tentative diagnosis based on history and clinical signs and the response to presumed appropriate treatment (metadiagnosis). The afebrile heartwater-like syndrome presents similarly to peracute heartwater but without the febrile reaction. Peracute cases of heartwater have a high mortality rate, enabling confirmation of the disease on post-mortem examination. Recognition of the afebrile heartwater-like syndrome is important to prevent deaths and identify the need for appropriate control measures.

scholarly journals Etude de l’effet rémanent de Mavi MNPV dans un champ de niébé

2020 ◽  
Vol 14 (6) ◽  
pp. 2219-2229
Author(s):  
A. Kindozandji ◽  
B.D. Datinon ◽  
K. Amevoin ◽  
A.N. Nondichao ◽  
A.I. Glitho ◽  
...  
Keyword(s):  
Research Work ◽  
Residual Effect ◽  
Maruca Vitrata ◽  
Sub Saharan Africa ◽  
Important Food ◽  
Food Legumes ◽  
Significant Difference ◽  
Sub Saharan ◽  
Rate Of Emergence ◽  
And Control

Le niébé est l’une des légumineuses alimentaires la plus importante dans toutes les régions de l’Afrique Sub-saharienne. L’objectif de ce travail était d’étudier l’effet rémanent de Mavi Multinucléo polyhedrovirus (Mavi MNPV) après la récolte du niébé au champ. Le champ a été traité 5 fois au biopesticide Mavi MNPV à la fréquence de sept jours. Deux semaines après la récolte, deux plants ainsi que les graines de chaque traitement sur chaque unité parcellaire ayant reçu les traitements de Mavi MNPV de 107, 108 et 109 virions/ml ont été collectés et amenés au laboratoire avec le substrat de développement de la plante (sable). Aucune des formulations issues des substrats sable, racines, feuilles, tiges et graines n’a affecté la mortalité des larves L2 et L3 de Maruca vitrata et aucune différence significative n’a été observée entre les traitements et le témoin. Quels que soient les traitements, le taux d’émergence des adultes est élevé ; ce qui signifie que la variation de la concentration de Mavi MNPV ne conditionne pas sa présence dans le sol, les tiges, les feuilles, les racines et les graines. Le biopesticide Mavi MNPV n’est pas persistant dans la nature.Mots clés : Niébé, Mavi MNPV, Maruca vitrata, Effet rémanent   English Title: Study of the residual effect of Mavi MNPV in a cowpea field Cowpea is one of the most important food legumes in all regions of Sub-Saharan Africa. The objective of this research work was to study the persistence effect of Mavi Multinucleus polyhedrovirus (Mavi MNPV) after field harvest of the cowpea. The field was treated 5 times with Mavi MNPV biopesticide at seven days. Two weeks after harvest, two plants as well as the seeds from each treatment on each plot unit that received Mavi MNPV treatments of 107, 108 and 109 virions / ml were removed and brought to the laboratory with the plant development substrate (sand). None of the formulations from sand, root, leaf, stem and seed substrates did not affect the mortality of L2 and L3 larvae of Maruca vitrata and no significant difference was observed between treatments and control. Regardless of the treatments, the rate of emergence of adults is high; this means that the variation in the concentration of Mavi MNPV does not condition its presence in soil, stems, leaves, roots and seeds. Mavi MNPV biopesticide is not persistent in nature.Keywords: Cowpea, Mavi MNPV, Maruca vitrata, Residual effect.      

scholarly journals Hypertension treatment and control in sub-Saharan Africa

BMJ ◽  
1998 ◽  
Vol 317 (7150) ◽  
pp. 76-76 ◽  
Author(s):  
J. Burdon ◽  
R W Montgomery ◽  
R. Walker ◽  
N Unwin ◽  
K G M M Alberti ◽  
...  
Keyword(s):  
Sub Saharan Africa ◽  
Hypertension Treatment ◽  
Sub Saharan ◽  
And Control

Susceptibility Profile of Aedes aegypti L. (Diptera: Culicidae) from Montclair, California, to Commonly Used Pesticides, With Note on Resistance to Pyriproxyfen

2019 ◽  
Vol 56 (4) ◽  
pp. 1047-1054 ◽  
Author(s):  
Tianyun Su ◽  
Jennifer Thieme ◽  
Taylor Lura ◽  
Min-Lee Cheng ◽  
Michelle Q Brown
Keyword(s):  
Aedes Aegypti ◽  
The United States ◽  
Urban Environments ◽  
Sub Saharan Africa ◽  
Modes Of Action ◽  
Breeding Populations ◽  
Laboratory Colony ◽  
Sub Saharan ◽  
The Tropics ◽  
And Control

Abstract The peridomestic anthropophilic Aedes aegypti L. (Diptera: Culicidae) is originated from the wild zoophilic subspecies Aedes aegypti formosus in sub-Saharan Africa, and currently has a broad distribution in human-modified environments of the tropics and subtropics worldwide. In California, breeding populations were initially detected in 2013 in the cities of Fresno, Madera, and San Mateo, and now can be found in 188 cities of 12 counties in the state. Recent genetic studies suggest that this species invaded California on multiple occasions from several regions of the United States and northern Mexico prior to initial detection. As an invasive species and vector for numerous arboviruses, Ae. aegypti is a primary target of surveillance and control in California. In southern California city of Montclair, a population was identified in September 2015, from which a short-term colony was established in an insectary. The susceptibility of this field population to commonly used pesticides with various modes of action, including 15 formulations against larvae and four against adults, was determined, in reference to a susceptible laboratory colony of the same species. No resistance was shown to most pesticides tested. However, tolerance or reduced susceptibility to spinosad, spinetoram, diflubezuron, and fipronil was detected, and modest levels of resistance to pyriproxyfen (resistance ratio = 38.7-fold at IE50 and 81.5-fold at IE90) was observed. Results are discussed based on the field usage and modes of action of the pesticides tested. Strategic selection and application of pesticides against this population of Ae. aegypti in the urban environments should be taken into consideration.

scholarly journals Recurrent Cholera Outbreaks in Sub-Saharan Africa: Moving beyond Epidemiology to Understand the Environmental Reservoirs and Drivers

Challenges ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
Willis Gwenzi ◽  
Edmond Sanganyado
Keyword(s):  
Epidemiological Studies ◽  
Sub Saharan Africa ◽  
Environmental Drivers ◽  
Future Research ◽  
Research Directions ◽  
Complex Interactions ◽  
Future Research Directions ◽  
Sub Saharan ◽  
And Control ◽  
Water Borne

Recurrent cholera outbreaks in sub-Saharan Africa (SSA) attracted a lot of research interest, raising questions about the effectiveness of current prevention and control methods. However, research on cholera and other water-borne diseases in Africa is dominated by epidemiological studies, while investigations on the environmental drivers and reservoirs of cholera remain scarce. The current discourse relating cholera to the environment in SSA is often limited to the rudimentary statement that, “cholera is caused by the consumption of contaminated water and food”. Yet, beyond this simplistic view, literature elsewhere shows that cholera outbreaks are controlled by its complex interactions with environmental drivers and reservoirs. This brings to question whether cholera can be eradicated in SSA without understanding these complex interactions. The current review seeks to (1) highlight the nature and dynamics of recent cholera outbreaks in SSA, (2) discuss the importance of environmental reservoirs of Vibrio cholerae, and anthropogenic and hydroclimatic drivers in controlling the dynamics of cholera outbreaks, and (3) highlight key knowledge gaps and future research directions, and the need to harness emerging research tools such as modeling, machine learning, data mining, and genomics techniques to better understand the cholera dynamics. By bringing to fore these often-overlooked issues in cholera research, we seek to stimulate discussion, and promote a shift toward cross-disciplinary research on cholera and other water-borne diseases in SSA and beyond.

scholarly journals Research on Invasive Nontyphoidal Salmonella Disease and Developments Towards Better Understanding of Epidemiology, Management, and Control Strategies

2020 ◽  
Vol 71 (Supplement_2) ◽  
pp. S127-S129
Author(s):  
Samuel Kariuki ◽  
Ellis Owusu-Dabo
Keyword(s):  
Burden Of Illness ◽  
Control Strategies ◽  
Sub Saharan Africa ◽  
Disease Entity ◽  
Middle Income ◽  
Diagnostic Strategies ◽  
Disease Epidemiology ◽  
Middle Income Countries ◽  
Sub Saharan ◽  
And Control

Abstract During the 11th International Conference on Typhoid and Other Invasive Salmonelloses held in Hanoi, Vietnam, a number of papers were presented on the burden of disease, epidemiology, genomics, management, and control strategies for invasive nontyphoidal Salmonella (iNTS) disease, which is increasingly becoming an important public health threat in low- and middle-income countries, but especially in sub-Saharan Africa (sSA). Although there were minor variations in characteristics of iNTS in different settings (urban vs rural, country to country), it was observed that iNTS has gained greater recognition as a major disease entity in children younger than 5 years. Renewed efforts towards greater understanding of the burden of illness, detection and diagnostic strategies, and management and control of the disease in communities in sSA through the introduction of vaccines will be important.

scholarly journals Determinants of Restrictive Spirometric Pattern in a Sub-Saharan Urban Setting: A Cross-sectional Population-based Study

2016 ◽  
Vol 10 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Eric Walter Pefura-Yone ◽  
Adamou Dodo Balkissou ◽  
Andre Pascal Kengne
Keyword(s):  
Heart Diseases ◽  
Population Based ◽  
Forced Expiratory Volume ◽  
Urban Setting ◽  
Sub Saharan Africa ◽  
Cross Sectional ◽  
History Of ◽  
Sub Saharan ◽  
And Control ◽  
Restrictive Pattern

Background Restrictive spirometric pattern is a risk factor for all-cause and cause-specific mortality. Objective We assessed the prevalence of restrictive pattern and investigated its determinants in a major sub-Saharan Africa city. Methods Participants were adults (≥ 19 years) who took part in a population-based survey in Yaounde (Cameroon) between December 2013 and April 2014. Restrictive pattern was based on a FVC below the lower limit of the normal (LLN) and a ratio forced expiratory volume in one second (FEV1)/FVC ≥ LLN (LLN-based restrictive pattern) or a FVC <80% and FEV1/FVC ≥ LLN (fixed cut-off based restrictive pattern). Determinants were investigated by logistic regressions. Results In all, 1003 participants [514 (51.2%) women] with a mean age of 33.7 years were included. The prevalence of restrictive pattern was 18.8% (95%CI: 16.6-21.2) based on LLN and 15.0% (13.0-17.2) based on fixed cut-off. LLN-based restrictive pattern was mild in 148 (78.3%) subjects, moderate in 35 (18.5%) and severe in 6 (3.2%). Determinants of LLN-based restrictive pattern were age ≥ 60 years [adjusted odds ratio 2.90 (95%CI 1.46-5.77), p=0.002), history of pulmonary tuberculosis [3.81(1.42-10.20), p=0.008], prevalent heart diseases [3.81 (1.20-12.12), p=0.024] and underweight [5.15(1.30-20.39), p=0.020]. Determinants were largely similar with slightly different effect sizes for fixed cut-off based restrictive pattern. Conclusion Restrictive pattern was very frequent in this city. Clinical implications These results enhance the needs to increase the efforts to prevent and control tuberculosis, cardiovascular diseases and underweight in this setting.

scholarly journals Electronic Cigarettes for Curbing the Tobacco-Induced Burden of Noncommunicable Diseases: Evidence Revisited with Emphasis on Challenges in Sub-Saharan Africa

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Jobert Richie N. Nansseu ◽  
Jean Joel R. Bigna
Keyword(s):  
Tobacco Smoking ◽  
Electronic Cigarettes ◽  
Sub Saharan Africa ◽  
Noncommunicable Diseases ◽  
Quit Smoking ◽  
Sub Saharan ◽  
Never Smokers ◽  
Second Hand Smoking ◽  
And Control

Introduction. This review examines whether electronic cigarettes (e-cigs) implementation or vulgarization in sub-Saharan Africa (SSA) could be helpful in curtailing the toll of tobacco smoking in the region. Discussion. There are about 1.3 billion smokers worldwide, with nearly 80% of them living in developing countries where the burden of tobacco-related illnesses and deaths is the heaviest. Studies report that e-cigs may facilitate smoking cessation, reduction, or abstinence and may pose only a small fraction of the risks of traditional tobacco cigarettes; e-cigs may also considerably reduce second-hand smoking. Thereby, implementation of e-cig use could help to substantially reduce the burden driven by tobacco smoking in SSA, in a particular context of lack of regulations and control policies towards this threat. However, the evidence is not clear on whether e-cigs are risk-free, especially if used in the long term. Conclusions. On the whole, if e-cigs were to be introduced in SSA, they should be strictly recommended to current and/or ex-smokers as a method to quit smoking or prevent relapse and never-smokers should be strongly encouraged to avoid using these devices. Bans on sales of e-cigs to youngsters should be legislated, e-cig advertisements prohibited, and their usage continuously controlled and monitored.

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