Showing papers in "African Journal of Biotechnology in 2009"
TL;DR: The technology involves efficient use of plants to remove, detoxify or immobilize environmental contaminants in a growth matrix (soil, water or sediments) through the natural, biological, chemical or physical processes of the plants.
Abstract: The current remediation technique of heavy metal from contaminated soil-water are expensive, time consuming and environmentally destructive. Unlike organic compounds, metals cannot degrade, and therefore effective cleanup requires their immobilization to reduce or remove toxicity. In recent years, scientists and engineers have started to generate cost effective technologies that include use of microorganisms/biomass or live plants to clean polluted areas. Phytoremediation is an emerging technology for cleaning up contaminated sites, which is cost effective, and has aesthetic advantages and long term applicability. It is best applied at sites with shallow contamination of organic, nutrient or metal pollutants that are amenable to one of the five applications; phytotransformation, rhizosphere bioremediation, phytostabilization, phytoextraction and rhizofiltration. The technology involves efficient use of plants to remove, detoxify or immobilize environmental contaminants in a growth matrix (soil, water or sediments) through the natural, biological, chemical or physical activities or processes of the plants. A brief review on phytoremediation of heavy metals and its effect on plants have been compiled to provide a wide applicability of phytoremediation.
431 citations
TL;DR: The present study suggests that the use of PGPR isolates PGB4, PGG2 and PGT3 as inoculant biofertilizers might be beneficial for rice cultivation as they enhanced growth of rice, and induced IAA production and phosphorus solubilization.
Abstract: Plant growth-promoting rhizobacteria (PGPR) are beneficial bacteria that colonize plant roots and enhance plant growth by a wide variety of mechanisms. The use of PGPR is steadily increasing in agriculture and offers an attractive way to replace chemical fertilizers, pesticides, and supplements. Here, we have isolated and characterized the PGPR from the rhizosphere soil of rice field for the enhancement of growth of rice. Rhizosphere soils were collected from different areas of Mymensingh in Bangladesh. Ten isolates of bacteria, designated as PGB1, PGB2, PGB3, PGB4, PGB5, PGT1, PGT2, PGT3, PGG1 and PGG2, were successfully isolated and characterized. Subsequently, to investigate the effects of PGPR isolates on the growth of rice, a pot culture experiment was conducted. Prior to seeds grown in plastic pots, seeds were treated with PGPR isolates and seedlings were harvested after 21 days of inoculation. Isolates PGB4, PGT1, PGT2, PGT3, PGG1 and PGG2 induced the production of indole acetic acid (IAA), whereas only PGT3 isolate was able to solubilize phosphorus. Most of isolates resulted in a significant increase in plant height, root length, and dry matter production of shoot and root of rice seedlings. Furthermore, PGPR isolates remarkably increased seed germination of rice. Among the ten isolates, PGB4 and PGG2 were found almost equally better in all aspects such as dry matter production, plant height and root length of rice, and IAA production. Isolate PGT3 was also found to be promising in IAA production having an additional property of phosphate solubilization. The present study, therefore, suggests that the use of PGPR isolates PGB4, PGG2 and PGT3 as inoculant biofertilizers might be beneficial for rice cultivation as they enhanced growth of rice, and induced IAA production and phosphorus solubilization.
346 citations
TL;DR: In this article, the authors reported the antioxidative activities of some methanolic plant extracts namely "ulam raja" (Cosmos caudatus), "kesum" (Polygonum minus), "selom" (Oenanthe javanica), "pegaga” (Centella asiatica) and "curry leaf" (Murraya koenigii" extracts.
Abstract: The presence of natural antioxidant in plants is well known This paper reports the antioxidative activities of some methanolic plant extracts namely ‘ulam raja’ (Cosmos caudatus), ‘kesum’ (Polygonum minus), ‘selom’ (Oenanthe javanica), ‘pegaga’ (Centella asiatica) and ‘curry leaf’ (Murraya koenigii) The analysis carried out was total phenolic content, ferric reducing power, ferric thiocyanate (FTC) and thiobarbituric acid (TBA) tests From the analyses, M koenigii had the highest yield extraction (165%), highest total phenolic content (3860 mg TAE/ 100 g fresh weight) and antioxidant activity (7060%) using FTC method Increasing the concentration of the extracts resulted in increased ferric reducing antioxidant power for all methanolic extracts tested TBA analysis showed that C caudatus extract had the highest antioxidant effect Total phenolic content had positive correlation with antioxidant capacity (r = 0451) This shows that the plants, especially M koeniigi, may be potent source of natural antioxidants
256 citations
TL;DR: In this article, the authors highlight the recent advances in the treatment and value addition of lignocellulosic wastes (LCW) with main focus on domestic and agro-industrial residues.
Abstract: This study highlights the recent advances in the treatment and value addition of lignocellulosic wastes (LCW) with main focus on domestic and agro-industrial residues. Mechanical, physical and biological treatment systems are brought into perspective. The main value-added products from lignocellulosic wastes are summarized in a manner that pinpoints the most recent trends and the future directions. Physicochemical and biological treatment systems seem to be the most favored options while biofuels, biodegradable composites and biosorbents production paints a bright picture of the current and future bio-based products. Engineered microbes seem to tackle the problem of bioconversion of substrates that are otherwise non convertible by conventional wild strains. Although the main challenge facing LCW utilization is the high costs involved in treatment and production processes, some recent affordable processes with promising results have been proposed. Future trends are being directed to nanobiotechnology and genetic engineering for improved processes and products. The paper presents state of the art review of the dual advantage of handling LCW for cleaner environment and production of renewable bio-products.
232 citations
TL;DR: The result revealed that both cell wall and membrane of the treated gram negative and gram positive bacteria were significantly damaged.
Abstract: The mechanism of antimicrobial activity of essential oils components; - terpineol, g-terpinene and eugenol was studied to evaluate their effect on the bacterial membrane against four strains of bacteria: Listeria monocytogenes, Streptococcus pyogenes, Proteus vulgaris and Escherichia coli. The study was done to observe changes in membrane composition by assaying for the leakage of protein and lipid using Bradford and van Handel’s method respectively. The oils components were capable of inducing cell lysis by the leakage of protein and lipid contents. Eugenol at 2 × MIC was highly effective toward protein content leakage after 120 min of exposure. Alpha terpineol and g-terpinene showed similar effect at 2 × MIC under the same condition. Gamma terpinene displayed the highest activity toward lipid content leakage at 2 x MIC while -terpineol and eugenol showed similar effect after 120 min of exposure. The result revealed that both cell wall and membrane of the treated gram negative and gram positive bacteria were significantly damaged.
181 citations
TL;DR: Soluble sugars exert their positive effects to protect plant cells from damage caused by cold stress through many ways including serving as osmoprotectants, nutrients as well as interacting with the lipid bilayer.
Abstract: Plants can enhance freezing tolerance by gradual exposure to low temperature known as cold acclimation. Soluble sugars have been confirmed to play an important role during the process. This is based on the fact they are most commonly detected in various species of terrestrial plants that have undergone seasonal cold acclimation. Soluble sugars exert their positive effects to protect plant cells from damage caused by cold stress through many ways including serving as osmoprotectants, nutrients as well as interacting with the lipid bilayer. In addition to these functions, more focus is on their important hormone-like functions as primary messengers in signal transduction nowadays. On the other hand, higher sugar concentrations can trigger leaf senescence, which indicates that the accumulation of soluble sugars during cold acclimation might impact on plants negatively. Further study can be done to investigate the mechanisms by which soluble sugars are involved in the plants’ response to the cold signal by advanced molecular biology methodology to examine sugar-regulated gene expression under cold condition.
173 citations
TL;DR: A review of the state of biogas technology research in some selected sub-Saharan African countries in peer reviewed literature is presented in this paper. But, there appears to be little research in the area of anaerobic digestion.
Abstract: This reviews aims to provide an insight and update of the state of biogas technology research in some selected sub-Saharan African countries in peer reviewed literature. This paper also aims to highlight the sub-Saharan countries’ strengths and weaknesses in biogas research and development capacity. An attempt is made to pinpoint future research in critically reviewing the biogas technology research. The methane-producing potential of various agriculturally sourced feedstocks has been researched, as has the advantages of co-digestion to improve carbon-to-nitrogen ratios and the use of pretreatment to improve the hydrolysis rates. Some optimisation techniques associated with anaerobic digestion including basic design considerations of single or two-stage systems, pretreatment, co-digestion, environmental conditions within the reactor such as temperature, pH, buffering capacity have been attempted in some of the researches in Nigeria, Tanzania, and Zimbabwe. However, there appears to be little research in biogas technology in many sub-Saharan African countries in internationally peer reviewed literature. Biogas production from large quantities of agricultural residues, animal wastes, municipal and industrial wastes (water) appears to have potential as an alternative renewable energy for many African countries if relevant and appropriate research is carried out to adopt the biogas technology to the local conditions in African countries. African scientists are urged to carry out research in biogas technology to locally demonstrate the feasibility, application, and adaptation of this technology and help improve the quality of energy supply in their respective countries.
170 citations
TL;DR: The present study deals with socio-economic documentation of medicinal plant species against jaundice and hepatitis and a total of 30 plant species belonging to 24 families were reported by local practitioners.
Abstract: The present study deals with socio-economic documentation of medicinal plant species against jaundice and hepatitis. A total of 30 plant species belonging to 24 families were reported by local practitioners for the treatment of jaundice and hepatitis. The most important plant species are Adiantum capillus, Boerhaavia procumbens, Equisetum debile, Carissa opaca,Cucumis sativus, Hordeum vulgare, Justacia adhatoda, Morus alba, Morus nigra, Phyllanthus emblica, Phyllanthus niruri, Plantago ovata, Prunus domestica, Punica granatum, Raphnus sativus, Rhus chinensis, Saccharum officinarum and Tamarandus indica.
146 citations
TL;DR: An inverse relationship between the susceptibility index and percent mortality and median developmental time is found; however, the numbers of F1 progeny, percent seed damage and seed weight loss were positively related with the susceptibility Index.
Abstract: of susceptibility was used to group the varieties. The variety, ‘BHQP-542’, had the least index of susceptibility and was regarded as resistant. The varieties, ‘Katumani’, ‘Melkasa-I’, ‘Melkasa-II’, ‘Melkasa-III’, ‘Coree’, ‘BH-541’, ‘BH-660’, ‘BH-540’, ‘Rare-I’, ‘Awasa-511’, ‘ACV3’ and ‘ACV6’, were moderately resistant. Weevils fed with the resistant variety produced low numbers of F1 progeny, had a high median developmental time and a low percentage of seed damage and seed weight loss. Maize varieties with a high F1 progeny tended to have a short median developmental time. An increasing number of F1 progeny resulted in an increasing seed damage and seed weight loss. We found an inverse relationship between the susceptibility index and percent mortality and median developmental time; however, the numbers of F1 progeny, percent seed damage and seed weight loss were positively related with the susceptibility index. The use of resistant varieties should be promoted in managing S. zeamais in stored maize under subsistence farming conditions in Africa.
142 citations
TL;DR: The ethnobotanical efficacy of Indian medicinal plants; Achyranthes aspera, Artemisia parviflora, Azadirachta indica, Calotropis gigantean, Lawsonia inermis, Mimosa pudica, Ixora coccinea, Parthenium hysterophorus and Chromolaena odorata were found to be ineffective or showed poor inhibition on tested human and phytopathogenic bacteria.
Abstract: The ethnobotanical efficacy of Indian medicinal plants; Achyranthes aspera, Artemisia parviflora, Azadirachta indica, Calotropis gigantean, Lawsonia inermis, Mimosa pudica, Ixora coccinea, Parthenium hysterophorus and Chromolaena odorata were examined using agar disc diffusion method against clinical bacteria (Escherichia coli and Staphylococcus aureus) and phytopathogenic bacteria (Xanthomonas vesicatoria and Ralstonia solanacearum). Leaves were extracted using different solvents such as methanol, ethanol, ethyl acetate and chloroform. Among treatments, maximum in vitro inhibition was scored in methanol extracts of C. odorata which offered inhibition zone of 10, 9, 12 and 12 mm against E. coli, S. aureus, X. vesicatoria and R. solanaccearum, respectively, followed by chloroform extract of the same plant leaf with inhibition zone of 8, 4, 4 and 4 mm, respectively. A significant inhibition of E. coli was found in aqueous and in all tested solvent extracts of A. indica. In case of S. aureus, maximum inhibition of 8 mm was obtained in aqueous extracts of A. indica and 6 mm from methanol extract of L. inermis. The minimum inhibitory concentration (MIC) value for the clinical bacteria ranged between 0.35 to 4.0 mg/ml and 0.25 to 4.0 mg/ml for phytopathogenic bacteria when tested with all four solvents extracts of C. odorata. Whereas, extracts of A. aspera, A. parviflora, C. gigantean, L. inermis, M. pudica and I. coccinea were found to be ineffective or showed poor inhibition on tested human and phytopathogenic bacteria.
138 citations
TL;DR: Agaricus bisporus extracts inhibited cell proliferation of HL-60 leukemia by the induction of apoptosis, and exhibited antibacterial activity against both gram positive and gram negative bacteria, as well as anticandidal activity against Candida albicans.
Abstract: In this study, ethanol extracts of an edible mushroom Agaricus bisporus, before and after boiling were investigated for antioxidant, anticancer and antimicrobial activities. To confirm the total antioxidant activity, ABTS, DPPH free radical-scavenging assay was carried, along with total phenolic and flavonoid concentration. In measuring ABTS and DPPH free radical scavenging activities, scavenging activity was found to be similar in both the extracts. Total flavonoids were 16.4±0.5 and 15.2±0.2 mg/g (Quercetin equivalent), the phenolics were 90.2±0.6 and 70.6±0.1 mg/g (Catechin equivalent) in raw and boiled extract, respectively. A. bisporus extracts inhibited cell proliferation of HL-60 leukemia by the induction of apoptosis. In addition, A. bisporus extracts exhibited antibacterial activity against both gram positive and gram negative bacteria, as well as anticandidal activity against Candida albicans. Therefore, A. bisporus could be considered as a functional food with antimicrobial, anti-oxidative and antiproliferative activity.
TL;DR: This review gives an overview of current status of genetic engineering applications being implemented to improve the process of phytoremediation design for restoration of human health and healthiness of the earth.
Abstract: The industrial revolution has increased the use of metals for various processes and operations. The waste containing heavy metals are transported to the environment; air, water and soil through the various sources which has increased the burden in the environment. Phytoremediation has been found a promising, cost-effective, aesthetically pleasing, in situ treatment technology for the remediation of heavy metal contaminants from the soil-water environment. A genetic engineering based phytoremediation strategy is being aimed to improve the performance of plants in effective removal of metals from environment. This review gives an overview of current status of genetic engineering applications being implemented to improve the process of phytoremediation design for restoration of human health and healthiness of the earth.
TL;DR: The overall data suggest an important contribution of Actinobacteria during bioremediation of crude oil-polluted soil, as well as total culturable hydrocarbon utilizing bacteria, heterotrophic bacteria and gas chromatographic analyses.
Abstract: The bacterial diversity in a tropical soil experimentally polluted with crude oil during a 57 days bioremediation was investigated in five 1 m2 plots using total culturable hydrocarbon utilizing bacteria, heterotrophic bacteria and gas chromatographic analyses. Four out of the five experimental plots received each 4 L of Bonny light crude oil while three treatment plots received 3 kg of NPK, urea fertilizers or poultry droppings with periodic tilling. Two plots, oil-contaminated and pristine served as controls. Bacterial counts increased 200 fold and 2 fold in the NPK treated and poultry-dropping-treated plots respectively, by day 31 post-inoculation. Detectable hydrocarbons in the treatment plots decreased by 84 - 95% and 96 - 99%, 31 and 57 days post-inoculation, respectively, compared with the petroleum contaminated control. Bacterial strains isolated included Rhodococcus sp., Nocardia sp., Arthrobacter sp., Gordonia sp., Mycobacterium sp., Corynebacterium sp., Bacillus sp., Micrococcus sp., Flavobacterium sp., Pseudomonas sp. and Alcaligenes sp. The overall data suggest an important contribution of Actinobacteria during bioremediation of crude oil-polluted soil.
TL;DR: Seven plant growth-promoting rhizobacterial strains were isolated from the rhizoplane and rhizosphere of wheat from four different sites of Pakistan and positively affected the germination of wheat as well as increased biomass and root shoot length by inhibiting R. solani growth.
Abstract: Seven plant growth-promoting rhizobacterial (PGPR) strains were isolated from the rhizoplane and rhizosphere of wheat from four different sites of Pakistan. These strains were analyzed for production of indole acetic acid (IAA), phosphorous solublization capability and inhibition of Rhizoctonia solani on rye agar medium. Strains WPR-51, WPR-42 and WM-30 were selected to test in planta antagonistic activity on two wheat verities infected with R. solani. These three strains belonging to Azotobacter and Azospirillum produced IAA ranging from 19.4 to 30.2 ug/ml and possessed phosphorus solublization capability. Out of these three strains WPR-51 and mixture of all three strains showed maximum inhibition of R. solani growth. These strains positively affected the germination of wheat as well as increased biomass and root shoot length by inhibiting R. solani growth when tested in pot experiments. PGPRs can be used as biocontrol agents that inhibit root rot and also strengthen the plant for better growth.
TL;DR: In this article, HPLC method was employed to quantify the amount of azadirachtin and nimbin present in the seed, leaf and the bark extracts of neem.
Abstract: The leaf and bark fraction extracts of Azadirachta indica A. Juss. (neem) grown in the foothills (subtropical region) of Nepal were evaluated for their antioxidant activity, total phenolic (TP) and total flavonid (TF) contents. HPLC method was employed to quantify the amount of azadirachtin and nimbin present in the seed, leaf and the bark extracts of neem. The result showed that the highest azadirachtin content was found in the methanolic extract of the seed (3300 ig/g dw). Similarly, the hexane fraction of bark showed the highest nimbin content (271 ig/g dw) followed by the methanolic extract (260 ig/g dw). Antioxidant activity was determined by measuring 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity, hydroxyl radical scavenging activity, DNA protection assay, metal chelating and the inhibition of peroxidation using linoleic acid system and their results were found at different magnitudes of potency. The results of TP content expressed in tannic acid equivalents ranged from 66.63 to 629.04 ig/mg in the bark extracts and 23.85 to 237.00 ig/mg in the leaf extracts. Likewise, the content of TF expressed in quercetine equivalents ranged from 12.87 to 17.07 ig/mg in the bark and 13.72 to 93.17 ig/mg in the leaf extracts.
TL;DR: A field experiment was conducted on clay-loam soil in Moghan region during 2007-2008 to investigate the effect of foliar application of zinc and iron on wheat yield and quality at tillering and heading stage.
Abstract: Intensive and multiple cropping, cultivations of crop varieties with heavy nutrient requirement and unbalanced use of chemical fertilizers especially nitrogen and phosphorus fertilizers reduced quality of grain production and the appearance of micronutrient deficiency in crops. A field experiment was conducted on clay-loam soil in Moghan region during 2007-2008 to investigate the effect of foliar application of zinc and iron on wheat yield and quality at tillering and heading stage. The experimental design was a randomized complete block design with three replicates. The SAS software package was used to analyze all the data and means were separated by the least significant difference (LSD) test at P obtained highest seed yield and quality.
TL;DR: The present data suggest that H2O2, a stress signal, could trigger the activation of antioxidants in seeds, which persists in the seedlings to alleviate the oxidative damage, leading to improvements in physiological attributes for the seedling growth under drought.
Abstract: Drought is an important environmental constraint limiting the productivity of many crops worldwide Seedling tolerance to drought is crucial for crop growth and development through the whole season under water-limited condition Experiments were conducted to investigate the effects of seed pretreatment by hydrogen peroxide (H2O2) on drought tolerance in wheat (Triticum aestivum L) seedlings H2O2-pretreated seeds exhibited 56% higher in germination rate than the water-pretreated seeds (control) under PGE-induced drought condition Level of H2O2 in seedlings arising from H2O2-treated seeds grown under drought stress was markedly lower than the controls, indicating the operation of antioxidant system in them These seedlings exhibited increased growth characteristics including higher net photosynthetic rate, leaf area and dry weight Moreover, H2O2 treatment improved water use efficiency (WUE) and proline level H2O2 pretreatment enhanced the membrane stability, as revealed from greatly reduced membrane damage rate (MDA) and malondialdehyde (MDA) content The seedlings showed the higher expression of antioxidative enzyme such as catalase (CAT) and ascorbate peroxidase (APX) The present data suggest that H2O2, a stress signal, could trigger the activation of antioxidants in seeds, which persists in the seedlings to alleviate the oxidative damage, leading to improvements in physiological attributes for the seedling growth under drought
Key words: wheat (Triticum aestivum L), seed pretreatment, H2O2, signaling, drought tolerance, membrane permeability, antioxidative system
TL;DR: The present results indicate that isolate KEH23 is a potential antibiotic producer agent for the biocontrol of plant and human pathogens.
Abstract: Sixteen antibiotic-producing Streptomyces sp. isolated from the North Cyprus soils were evaluated for their ability to inhibit in vitro against six filamentous fungi including human and plant pathogens. One promising strain, designed as KEH23 with strong antifungal activity, was selected for further studies. This isolate was identified as Streptomyces sp. based on a great variety of morphological, cultural, physiological and biochemical characteristics. Its antifungal activity was confirmed in batch culture. In order to standardize the antibiotic production some cultural conditions like different incubation temperatures (20.0, 25.0, 30.0 and 37.0°C), carbon sources (glucose, glycerol, starch and sucrose), pH (6.0, 7.0, 7.5, 8.0 and 9.0) and incubation time in hours (24, 48, 72, 96 and 120) were determined. During fermentation, growth, pH and antibiotic production were monitored at 12 h intervals. Penicillium sp. was most sensitive to the produced compound(s) followed by Candida albicans, Cladosporium oxysporum and Alternaria alternata with an inhibition zone 28.0, 20.0, 16.0 and 15.0 mm, respectively. In addition, antibacterial activity of this strain was determined against human pathogenic bacteria such as Staphylococcus aureus, Klebsiella pneumoniae, Kocuria rhizophila, Escherichia coli, Salmonella typhimurium and methicillin-resistant Staphylococcus aureus (MRSA). The present results indicate that isolate KEH23 is a potential antibiotic producer agent for the biocontrol of plant and human pathogens.
TL;DR: In this paper, the proximate vitamins and mineral elements and phytochemical compositions of Azadirachta indica, Vernonia amygdalina and Gongronema latifolium were quantitatively determined using standard methods and compared.
Abstract: As part of an investigation into the antidiabetic mechanism of some indigenous medicinal plants, the proximate, vitamins and mineral elements and phytochemical compositions of Azadirachta indica, Vernonia amygdalina and Gongronema latifolium were quantitatively determined using standard methods and compared. Of the 3 plants G. latifolium had highest (p<0.05) crude protein and fat contents but lowest in fibre composition, whereas A. indica with highest fibre content had lowest crude protein composition. Fat and ash were lowest in V. amygdalina . Also G. latifolium showed highest composition (p<0.05) of vitamins A, E and niacin content compared to A. indica and V. amygdalina. A. indica and V. amygdalina have higher (p<0.05) vitamin C and riboflavin composition. Flavonoids, saponins and polyphenols were significantly predominant (p<0.05) in V. amygdalina relative to A. indica and G. latifolium , whereas alkaloids and HCN were highest (p<0.05) in A. indica . However, G. latifolium had the highest composition of tannins among the three plants. There appear to be a complement of biochemicals in the leaves of these plants which may account for reported hypoglycemic and antihyyperglycemic action.
TL;DR: An ethnobotanical study on the medicinal and economic plants of Malam Jabba valley, District Swat was conducted with the aims of documenting the inventory of medicinal plants, examinining the current status of the medicinal plants trade and investigating the linkages in the market chain starting from collectors to consumers.
Abstract: An ethnobotanical study on the medicinal and economic plants of Malam Jabba valley, District Swat was conducted with the aims of documenting the inventory of medicinal plants, examinining the current status of the medicinal plants trade and investigating the linkages in the market chain starting from collectors to consumers. The survey reported 50 species of plants belonging to 33 families as ethnobotanically important. These species are used as drugs for treating diseases in traditional system of medicine. The detailed local uses, recipe preparation along with their local names and diseases treated were recorded for each species. Market survey revealed that the structure of medicinal plant trade is complex and heterogeneous, involving many players. The collectors are often not aware of the high market prices and medicinal values, and most of the collected material is sold to local middlemen at a very low price. There was an increase of 3 to 5 folds in prices from collectors to the national market. Training in sustainable harvesting and post harvesting of wild medicinal plant resource, trade monitoring, equitable sharing of benefits of wild resources, improved control on harvesting and trade for the conservation of resources, enhancement of cultivation efforts, future research into trade in wild harvested plants, community participation in natural resource management and value addition in the herbal products to maximize the benefits are recommended.
TL;DR: The results indicate that these species of seaweed collected from the Atlantic and Mediterranean coast of Morocco present a significant capacity of antibacterial activities, which makes them interesting for screening for natural products.
Abstract: Antibacterial activity of methanolic extracts from 32 macroalgae (13 Chlorophyta and 19 Phaeophyta) from the Atlantic and Mediterranean coast of Morocco were evaluated for the production of antibacterial compounds against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Klebsiella pnomeuniae ATCC 700603 and E. faecalis ATCC 29213. Our results indicate that these species of seaweed collected from the Atlantic and Mediterranean coast of Morocco present a significant capacity of antibacterial activities, which makes them interesting for screening for natural products.
TL;DR: The strains isolated from weeds of Khewra salt range particularly Rkh3 appears more promising for potential biofertilizers in saline fields and inoculation of strains on soybean seedlings resulted in better growth and higher proline contents than control plants.
Abstract: Present investigation was made to isolate and characterize plant growth promoting rhizobacteria (Rkh1 - Rkh4) from rhizosphere of four weeds: Chrysopogon aucheri,Lactuca dissecta, Solanum surratense and Sonchus arvensis thriving under high salinity (EC: 2.3 dS/m) of Khewra salt range and the results were compared with strain Rak isolated from rhizosphere (EC: 0.2 dS/m) of Solanum surratense grown in arid area of district Attock. The tolerance of all the strains was checked against the salt present in culture media in the form of rhizospheric soil filtrate of weeds collected from Khewra salt range. The nutrient contents of rhizospheric soil of weeds were measured. All the strains were capable to produce phytohormones indole-3-acetic acid (IAA), gibberellic acid (GA3), trans-zeatin riboside (t-zr) and abscisic acid (ABA) in the culture media. Inoculation of strains on soybean seedlings treated with or without 20 dS/m NaCl resulted in better growth and higher proline contents than control plants. The strains isolated from weeds of Khewra salt range particularly Rkh3 appears more promising for potential biofertilizers in saline fields.
Key words: Plant growth promoting rhizobacteria, nutrient contents, salt tolerance, phytohormones production, proline contents.
TL;DR: The major characteristics of this enzyme family and the principal studies that have contributed to a better knowledge of its role in mosquito insecticide resistance are described.
Abstract: Mosquito glutathione S-transferases (GSTs) have received considerable attention in the last 20 years because of their role in insecticide metabolism producing resistance. Many different compounds, including toxic xenobiotics and reactive products of intracellular processes such as lipid peroxidation, act as GST substrates. Elevated levels of GST activity have been reported in organophosphate, organochlorine and pyrethroid resistant mosquitoes. Particulary GST-based resistance is considered the major mechanism of DDT resistance in anopheline species. To date different GST enzymes structurally conserved have been identified suggesting that they may have an important role on common pathways of compound detoxification. In this review we describe the major characteristics of this enzyme family and the principal studies that have contributed to a better knowledge of its role in mosquito insecticide resistance. Finally some aspects on insect GST-based resistance and their implications in traditional biochemical assays for detecting and monitoring GST activity are discussed.
TL;DR: This paper will give short review of recent studies in which the effects of various prebiotics have been evaluated for potential application in the aquacultural production of fish and shrimp.
Abstract: It has been documented in a number of food animals that gastrointestinal bacteria play important roles in affecting the nutrition and health of the host organism. Thus, various means of altering the intestinal bacteria to achieve favorable effects such as better resistance to pathogens, enhancing growth and immune stimulation of the host organism have been investigated in various fish and shrimp. In this respect, probiotics and prebiotics are used in farm animal and for aquaculture, although the probiotic approach has been extensively used and advocated, viability after ingestion is difficult to guarantee and almost impossible to prove. The prebiotic concept dictates that non viable dietary components fortify certain components of the intestinal flora. This concept has the advantage that survival of the ingested ingredient through the upper gastrointestinal tract is not a prerequisite because it is indigenous bacterial genera that are targeted. Despite some positive effects prebiotic supplements on fish and crustaceans have been published however it seems such information for aquatic organism is inadequate. This paper will give short review of recent studies in which the effects of various prebiotics have been evaluated for potential application in the aquacultural production of fish and shrimp.
TL;DR: The results showed that C-955 is the cultivar to be recommended for saline soils and Progen-1550 was more sensitive to salinity in this study.
Abstract: This study was conducted to investigate the effects of salt stress on germination of six maize (Zea mays L.) cultivars (ADA-523, Bora, C-955, PR 3394, Progen 1150 and Trebbia). The degrees of salinity tolerance among these cultivars were evaluated at seed germination stage at six different salt concentrations (0, 50, 100, 150, 200 and 250 mM NaCl). The results showed that in all cultivars as the salt concentration increased, both germination percentage and germination index decreased significantly. Responses of cultivars to salt stress indicated differences. For all salt concentrations, C-955 had the highest germination percentage and germination index. Salt concentration decreased shoot and root dry weight. Bora and C-955 had the lowest reduction of shoot and root dry weight, respectively. Progen-1550 had the highest reduction of shoot and root dry weight. On the other hand, C-955 showed better results than the other cultivars in respect of salt tolerance index. The results showed that C-955 is the cultivar to be recommended for saline soils. Progen-1550 was more sensitive to salinity in this study.
TL;DR: This paper reviews the recent research progress on genetic methods of resistance, the status and existing problems, traditional breeding, the main resistance mechanism, molecular markers and genetic engineering of resistance genes.
Abstract: Verticillium dahliae, a soil-borne pathogen, causes Verticillium wilt, one of the most serious diseases in cotton, deleteriously influencing crop’s production and quality. Verticillium wilt has become a major obstacle in cotton production since Helicoverpa armigera, the cotton bollworm, became effectively controlled in recent years. The wilt is becoming a key subject of research in cotton-resistance genetics, breeding and plant pathology. This paper reviews the recent research progress on genetic methods of resistance, the status and existing problems, traditional breeding, the main resistance mechanism, molecular markers and genetic engineering of resistance genes. It is hoped that new breeding methods and new varieties resistant to Verticillium wilt will be developed in the very near future.
TL;DR: An antibacterial substance produced by an isolated Bacillus subtilis strain LFB112 from Chinese herbs, was identified as bacteriocin and was effective against both Gram-positive and Gram-negative bacteria involved in domestic animal diseases.
Abstract: The emergence of multidrug-resistant pathogens and the restriction on the use antibiotics as growth promoters in feed have drawn attention to the search for possible alternatives. Much interest has been focused on bacteriocins because they exhibit inhibitory activity against pathogens. In this study, an antibacterial substance produced by an isolated Bacillus subtilis strain LFB112 from Chinese herbs, was identified as bacteriocin. It was effective against both Gram-positive and Gram-negative bacteria involved in domestic animal diseases, including Escherichia coli, Salmonella pullorum, Pseudomonas aeruginosa, Pasteurella multocida, Clostridium perfringens, Micrococcus luteus, Streptococcus bovis and Staphylococcus aureus. Two multidrug-resistant clinical isolates and a phytopathogenic yeast strain were also inhibited. The antimicrobial substance was secreted at the middle of the exponential phase, whose activity was sensitive to proteinase K and pronase E but resistant to the proteolytic action of papain, trypsin and pepsin. The antimicrobial activity was relatively heat resistant and also active over a wide range of pH 3 - 10. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that the active peptide had an apparent molecular weight of about 6.3 kDa. It exhibited a bactericidal activity against S. aureus IVDC C56005. Such characteristics indicate that this bacteriocin may be a potential candidate for alternative agents to control important pathogens in domestic animal diseases.
TL;DR: The high incidence of UTIs reported in this study should be of great concern, as not only do UTIs pose a threat to health, but they also impose an economic and social burden due to the stigma associated with these infections.
Abstract: This study reports the incidence of urinary tract infections (UTIs) among 80 pregnant women attending antenatal clinics at Oluyoro Catholic Hospital (OCH), Ibadan, Nigeria, as well as the isolation and identification of the pathogens responsible for the infection. A total of 80 clean voided mid-stream urine samples were collected from pregnant women between the ages of 21-40 years. The results showed that the incidence of UTIs in this study population was 47.5%, and 38 bacterial isolates were identified based on colonial morphology, microscopic characteristics, and biochemical tests. The most predominant bacterium was Escherichia coli 16 (42.1%). This was followed by Staphylococcus aureus 11 (28.9%), Klebsiella aerogenes 7 (18.4%), Pseudomonas aeruginosa 2 (5.3%), and a mixed culture of K. aerogenes and Staphylococcus aureus 2 (5.3%). Urine microscopy revealed the presence of pus cells in 15 of the urine samples collected. Two urine samples, representing 2.5% of the samples, contained yeast cells, suggesting that candidiasis was also predominant. The high incidence of UTIs reported in this study should be of great concern, as not only do UTIs pose a threat to health, but they also impose an economic and social burden due to the stigma associated with these infections.
TL;DR: Substantial increased in sedimentation rate was observed with increasing flocculants dosage though the flocculation efficiency and cell viability were not significantly varied.
Abstract: The possibility of using flocculation technique for the separation of microalgae, Chaetoceros calcitrans, biomass from the culture broth was investigated. The flocculation experiments were conducted in 500 mL beaker using culture broth obtained from 10 L photobioreactor. The harvesting efficiency of 90 and 60% was obtained in flocculation without flocculants conducted for 10 days at 27oC (in light and dark) and 4oC (dark), respectively. Harvesting efficiency higher than 90% with short settling time was achieved by adjusting the culture pH to 10.2 using either sodium hydroxide (NaOH) or potassium hydroxide (KOH). Improved cell viability (> 80%) and settling time with a slight improvement of flocculation efficiency was achieved by the addition of polyelectrolytes flocculant (Magnafloc® LT 27 and LT 25). However, the flocculants were only functioned when the pH of the microalgae culture was pre-adjusted to a certain value that promotes cells entrapment and surface charge neutralization prior to flocculation process. The flocculation efficiency and cell viability obtained in flocculation with Magnafloc® (LT 25 and LT 27) was comparable to that obtained in flocculation with chitosan. When chitosan and Magnafloc® (LT 25 and LT 27) were used as flocculants, the highest flocculation efficiency of C. calcitrans cells was observed at pH 8 and 10.2, respectively. Substantial increased in sedimentation rate was observed with increasing flocculants dosage though the flocculation efficiency and cell viability were not significantly varied.
TL;DR: Artemisia absinthium (Asteraceae) is widely used in Iranian traditional medicine and its effects may be correlated with the presence of antioxidant compounds as discussed by the authors, however, it is not suitable for use in medical applications.
Abstract: Artemisia absinthium (Asteraceae) is widely used in Iranian traditional medicine. Its effects may be correlated with the presence of antioxidant compounds. Methanolic extract of A. absinthium aerial part at flowering stage was screened for antioxidant activities by five complementary test systems. Also, its antidepressant activity was determined by forced swimming (FST) and tail suspension tests (TST). The extract showed good antioxidant activity. Also, the extract showed good reducing power activity between 50 and 800 igml-1. The extract exhibited a good activity in H2O2 scavenging (IC50 = 243 ± 12.15 ig ml-1). IC50 for iron ion chelating activity was 419 ± 20.95 ig ml-1. Quercetin, BHA, EDTA and ascorbic acid used as positive controls in parallel experiments. The extract showed high phenolic and flavonoid contents. Extract showed good antidepressant activity in FST. The extract shortened remarkably the immobility period during the FST and TST and exhibited a dose dependent activity. All test groups were significantly different form control group (P 0.05) in TST. LD50 was 3700 mg/kg. These results introduced A. absinthium aerial parts as an easily accessible and edible source of natural antioxidants and antidepressant.