Aims: evaluate the effect of the nutrient content of the medium on the sporulation percentage and the efficiency of ethanolic activation on the outgrowth of Bacillus spp. Place and Duration: Department of Microbiology of the University of Yaoundé I between june 2020 and September 2021. Methodology: In order to contribute to the understanding of the effect of the environment of spore origin on the ability to sporulate and outgrow in foods, spores of Bacillus cereus and Bacillus subtilis were produced in different media differenciated by the carbohydrates, lipids and proteins composition. Mathematical models predicting sporulation rates and germination yields of heat- and ethanol-activated spores were evaluated as a function of the factors selected. The reliability of these models was assessed by comparing the predicted values with those obtained in real food. Results: It was found that spores originating from high carbohydrates and proteins media had high sporulating and germination rates. It was found that the origin of the spores, mainly the carbohydrate and protein content, resulted in high sporulation rates and that spores from nutrient-rich media germinated faster than those from nutrient-poor media. Germination efficiency varied from strain to strain depending on the method of activation and the composition of the medium in which the spores were produced. The mathematical models obtained were validated in food matrices with correlation of predicted and observed values higher than 0.85. Conclusion: The ethanolic activation of spore varies depending on the strain and the nutrient content especially the fat content in sporulating medium. The proteins and carbohydrates have significant content for thermal activation.

In Cameroon, like elsewhere, medicinal plants are successfully used to treat gastro-intestinal diseases. Entada africana is a medicinal plant which different parts are used to treat stomach pain, diarrhea, dysentery and many other diseases. In order to show the efficiency of this plant in the treatment of gastrointestinal disorders, its antibacterial, antiulcerogenic and antioxidant activities were evaluated at Department of Microbiology (Laboratory of Microbiology) and Department of Animal Biology & Physiology (Animal Physiology Laboratory); Faculty of Science, University of Yaoundé I, between Febuary 2015 and July 2016. Crude extract of E. africana was obtained using methylene chloride/methanol mixture and fractions by successive exhaustion in hexane, methylene chloride and ethyl acetate. Phytochemical analysis of secondary metabolites was done using colorimetric tests. The antibacterial study consisted to determine Inhibition Diameters (ID) by agar diffusion as well as the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) using the tube macro dilution method against E. coli, S. typhi, P. aeruginosa, K. pneumonia, S. aureus and B. cereus. The anti-ulcerogenic and antioxidant properties of the methylene chloride/methanol crude extract was evaluated using indomethacin-induced ulcer in rats and levels of reduced glutathione (GSH) and malondialdehyde (MDA) in the stomach homogenate were measured. The phytochemical study revealed the presence of phenolics compounds. The Methylene chloride/methanol, hexane, methylene chloride and ethyl acetate extracts were active on the tested microorganisms with the following results respectively for ID and MIC: 8.50 mm ± 0.50 ≤ DI ≤ 18.00 mm ± 1.00 and 1.56 mg/mL ≤ MIC ≤ 6.25 mg/mL. The anti-ulcerogenic test showed that the methylene chloride/methanol extract exhibited a cytoprotective effect with ulcer indices varying from 1.98 ± 0.24 to 1.36 ± 0.14 when the rats were pretreated at 200 and 400 mg/kg, respectively. Tissue levels of MDA reduced (23.04 %) while those of GSH increased (14.29%) following treatment with extract. The antibacterial, anti-ulcerogenic and antioxidant activities exerted by these plant extracts could be due to the presence of phenolic compounds. These properties would make this plant an

Immunomodulatory therapy is now being recognized as an alternative to conventional chemotherapy for a variety of disease conditions, involving the impaired immune response of the host. The goal of this study is to valorize Gouania longipetala (Hemsl.) like potential source of drugs against immune system dysfunction. This medicinal plant is commonly used in the Cameroonian pharmacopeia to cure a lot of diseases including inflammatory diseases. In this work, we evaluated the immunomodulation properties of infused stems extract (GLE) and triterpenes from G. longipetala (Hemsl.), with respect to the phagocytosis. GLE was obtained by infusion of dry bark powder in water and the triterpenes were isolated after fractionation of GLE in solvent systems following by column chromatography. The structure elucidation of isolated compounds was based on analysis of spectroscopic data including 1D- and 2D-NMR. The immunomodulation activity was evaluated by two methods. Firstly, the capacity of GLE and triterpenes to modulate phagocytic activity of polymorphonuclear (PMNs) cells was assessed in vitro against Candida albicans. Secondly, the ability of GLE to modulate reticuloendothelial system was investigated in vivo on wistar rats by carbon clearance test. Two triterpenes were isolated, alphitolic and epigouanic acids. The stimulation percentage of PMNs by plant extracts was ranged between 4.25 and 42.55% with GLE and between 14.89 and 46.80% with alphitolic acid. Epigouanic acid show biphasic activity profile, with stimulation of phagocytic activity of PMNs cells at lower concentrations and suppression effects at higher concentrations. In vivo test showed that GLE liberates the glutathione particles from animal’s liver and enhance the phagocytic activity by stimulating the reticuloendothelial system. The phagocytic index obtained was ranged between 0.020 ± 0.004 and 0.074 ± 0.006. The results obtained from this study show that extract from G. longipetala (Hemsl.) modulate phagocytic activity and would be therefore the potential sources of drugs against immunological disorders.

Aims: This work aims to determine the ideal conditions for ethanol activation of spores during their enumeration and compare to thermal activation which is the reference method. Place and duration: Department of Microbiology of the University of Yaoundé I between May2016 and June 2018. Methodology: Bacillus cereus and Bacillus subtilis spores were activated according to an experimental central composite design with three-factor. The factors considered were exposure time, ethanol concentration, pH and activation temperature according to the types of activation. Germination yield was carried out by individually monitoring each spore of a population on solid medium in order to determine the population germination kinetic parameters (time and rate of colony appearance within a population during germination) and germination yields. These parameters were compared with those obtained after thermal activation known as a reference method. Results: The factors strain and pH, significantly influenced the rate of spore germination within the population after ethanol activation. In the case of thermal activation, the specie and activation temperature were the most influential factors. The best germination yields were obtained for alcoholic activation of spores at 30% ethanol for 60min exposure at pH7, while for thermal activation the best yields varied from one strain to another depending on the activation conditions. Conclusion: Ethanol activation can be considered as a good substitute of thermal activation during spore enumeration provided activation conditions are well controlled. This is in our opinion the first detailed study comparing ethanol activation to heat activation of Bacillus spores. It will impact future revisions of spore enumeration protocols proposed by norms that take into consideration spore activation and reduce bias in spore enumeration.

An ethnopharmacology survey concerning the medicinal plants used in Bandjoun village (La'Djo) to cure infectious diseases was carried out in three districts of this village. The survey led to the identification of 79 medicinal plants species listed in 41 families. These plants were cited to be use to treat about 25 infectious diseases among which malaria, diarrhea and intestinal-worms were the most cited. Chromolaena odorata, Voacanga africana, Moringa oleifera, Mammea africana, Euphorbia hirta, Psidium guajava, Allium cepa, Enantia chlorantha, Alstonia boonei and Picralima nitida, were the ten most cited plants. Extractions of parts of these last plants were performed in hydro-ethanol (3:7) solvent and then tested in-vitro against an Escherichia coli isolate. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were assessed by microdilution assay and the time-kill assessment was carried out by measure of log reduction in viable cell count, on a period of 48 hours. MIC and MBC determined were ranged between 1.00 and 32.0 mg/mL. Eighty percent (80%) of plant extracts tested have been bactericidal (MBC/MIC = 1 or 2) after 24 hours of incubation. A significant dose-dependent decreasing (P<0.05) in test organisms population was observed in the time with log reduction in viable cell count was ranged between 0.13 log10cfu/mL and 100% of inhibition. This antimicrobial activity has been attributed to metabolites groups in plant extracts namely, Phenols, flavonoids, tannins, coumarins, terpenoids, anthraquinones, cardiac glycosides, anthocyanides and alkaloids. These results obtained against Escherichia coli give a scientific validation to the traditional medical knowledge of Bandjoun-village populations and confirm some of the plants identified like a source of potentially active compounds against infectious diseases.

The present study evaluates the in vitro antioxidant activity of the leaves and stem-barks extracts and fractions of Ochna schweinfurthiana.To this effect, the different extracts were obtained by maceration in four solvents namely ethyl acetate, methanol, acetone and water-ethanol mixture (20-80).The methanol extract which exhibited the best antioxidant activity was partitioned in hexane and ethyl acetate.The ethyl acetate fraction was fractionated by column chromatography with the aid of methyl dichloride/methanol / MeOH) solvent system at different polarities.The antioxidant activity of the extracts and fractions was assessed by the 2,2-diphenyl-1-picrilhidrazil (DPPH), ferric reducing antioxidant power assay (FRAP) and the total polyphenol content was evaluated using the Folin-Ciocalteu reagent.The results were analyzed using SPSS 20 presented as mean The results phytochemical screening confirmed the abundance of flavonoids and catechic tannins in the methanol and water-ethanol extracts whose content vary between 37.83 ± 1.6 mg ascorbic acid equivalent (EAA)/g dry weight (dw) and 96.4 ±2.33 mg EAA/g dw.The leaves methanol extract possess the best antiradical power (AP) of 0.00114 ± 0.00001 g/mg and the best ferric reducing antioxidant power (542.33±16.51mg EAA/g dw).The F3 fraction obtained using /MeOH 5/1 elution system possess the best AP of 0.00125 ± 0.00001 g/mg identical to that of ascorbic acid (AP = 0.00125 ± 0.00002 g/mg) and the strongest ferric reducing antioxidant power (508.66 ± 18 mg EAA/g dw).A positive correlation between the two antioxidant tests and the polyphenols content was obtained.Thus, Ochna schweinfurthiana could be used by the population to prevent some diseases caused by oxidative stress, due to its high antioxidant effect.

The purpose of this study was to evaluate the in-vitro antibacterial activity of hydro-ethanol extracts of stems, barks and leaves of Annona muricata against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabillis and Bacillus cereus, followed by the evaluation of their antioxidant activities. The sensitivity of the bacteria to extracts was evaluated by the well diffusion method and the inhibition parameters of the bacterial growth were determined by the micro-dilution assay. The Minimum Bactericidal concentrations (MBC) obtained were between 6.25 and 25.00 mg/ml. Pseudomonas aeruginosa was the most sensitive strain with a MBC value of 6.25 mg/ml obtained from leaves extract. The antioxidant activity was evaluated using1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and ferric reducing antioxidant power (FRAP) assay. Hydro-ethanol extract of barks exhibited the highest DPPH scavenging activity of 0.010 ± 0.004 g/mg and the highest reducing power with ascorbic acid equivalence of 49.45 ± 0.067 mg EAA/gw. This extract has presented only the highest phenolic content 25.00 ± 1.070 mg EAA/gw. The phytochemical screening revealed that the plant contain bioactive compounds such as steroids, triterpenes and alkaloids. These results confirm the use of this plant in traditional medicine for the treatment of bacterial infections and diseases associated to oxidative stress such as diabetes.

Introduction Glaucoma is a public health issue worldwide, particularly in Africa. In Cameroon, the prevalence rate of primary open-angle glaucoma (POAG) ranges between 4.5% and 8.2%. Helicobacter pylori (HP) has been implicated in digestive and extra-digestive diseases, including glaucoma. The objective of this work was to evaluate the implication of CagA- and VacA-positive strains of HP in POAG using a case-control design. Methods An analytical study was conducted from October 2013 to December 2013. Participants were recruited in eye care centers in Yaoundé. Enzyme-linked immunosorbent assays (ELISAs) were carried out in the La Grace Laboratory in Yaoundé. Results The total sample consisted of 50 POAG patients and 31 controls with a mean age of 58.5 ± 12.2 years and 45.5 ± 14.6 years, respectively. The prevalence rates of HP in the POAG and control groups were 74% (37/50) and 87% (27/31), respectively (P = 0.125). The prevalence rates of CagA-positive HP seropositivity in the POAG and control groups were 26% and 22.58%, respectively (P = 0.47), and the prevalence rates of VacA-positive HP participants were 6% and 0%, respectively (P = 0.22). Conclusion The HP prevalence rates among POAG patients and controls were 74% and 87%, respectively. There was no significant difference between prevalence rates of HP in the POAG and control groups. There was no association between POAG and CagA- or VacA-positive HP infection.

The purpose of this study was to evaluate anti-trichophytic effects of Baillonella toxisperma (Pierre) extracts against Trichophyton rubrum and Trichophyton soudanense.The tests were performed by the agar dilution method and the results have showed the effective inhibition of the mycelia growth of theses strains by B. toxisperma (Pierre) extracts.After 7 days of incubation at 28°C, the percentages of mycelia growth inhibition PI (%) by plant extracts and fluconazole were range between 20.81 and 100% on T. soudanense, and between 19.92 and 100% on T. rubrum.Some B. toxisperma (Pierre) extracts were exhibited similar anti-trichophyton activities compared to those obtained with fluconazole which was used like reference antifungal drug (p < 0.05).The best anti-trichophyton activities of B. toxisperma (Pierre) extracts were obtained at 5 mg/ml on T. Rubrum with almond oil and hexane phase of water-hexane partition of hydro-ethanol crude extract of barks bromobentseeni (HBb), and at 10 mg/ml on T. soudanense with (HBb).This anti-trichophyton activity of B. toxisperma (Pierre) extracts was attributed to secondary metabolites.The phytochemical analysis has showed that the plant contain bioactive metabolites groups such as phenols, flavonoids, saponins, coumarin, tanins, anthocyanins, lipids and triterpenes.The metabolic groups have been mentioned in several studies for their antifungal activities.The results from this study provide a scientific validation for the ethnomedicinal uses of B. toxisperma (Pierre) in the treatment of fungal infections.

An ethnopharmacological survey concerning medicinal properties of Baillonella toxisperma (Pierre) was carried out by interview with the indigenous population of Dimako village situated in the East region of Cameroon. The result showed that the plant is implicated in the treatment of many infections among which is fungal infections. To confirm the antifungal property of B. toxisperma (Pierre), the barks and leaves of the plant were collected and serial extractions in water, hydro-ethanol mixture (3:7), ethanol, methanol and ethyl acetate were performed in vitro. One part of the hydro-ethanol (3:7) extract was degreased by mixing in water-hexane mixture (1:1). The extracts were then tested in vitro against Candida albicans, Candida parasilopsis, Candida sp. responsible for superficial, deep or systemic mycosis and against Cryptococcus neoformans responsible for sub-acute meningitis in immunodeficient individuals. The susceptibility of yeasts to plant extracts was evaluated using the wells diffusion method and yeasts growth inhibition parameters were evaluated according to the proposed National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 standard guidelines (2002). The minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) determined were between 0.93 and 30.0 mg/ml. The extracts were fungicidal on clinical yeasts tested with MFC/MIC ratio of 1 or 2. The hexane phase HT2 from the hydro-ethanol crude extract of the barks gave the best antifungal activity on C. neoformans, with a MIC of 0.93 mg/ml and a MFC of 1.87 mg/ml. This activity was similar to the one obtained with fluconazole. Phytochemical screening revealed the presence of polyphenols, phenols, tannins, flavonoids, steroids, alkaloids, saponins, phlobatannins, triterpenes, anthocyanins, cardiac glycosides, leucoanthocyanins and fats, which are bioactive substances. The results could explain scientific validation to the traditional medical uses of B. toxisperma (Pierre) to treat fungal infections. Key words: Cameroon, Baillonella toxisperma (Pierre), ethnopharmacology survey, fungal infections, bioactive compounds.

This study evaluated the in vitro antibacterial activity of the ethyl acetate, acetone, methanol and hydro-ethanol mixture (2: 8) extracts of the leaves and stem-barks of Baillonella toxisperma (Pierre), harvested in the East and center regions of Cameroon, on Staphylococcus aureus, Salmonella typhi, Proteus mirabilis and Bacillus cereus F3748. These bacteria are usually responsible for diarrheal diseases and in severe cases can lead to the dead of patients. The susceptibility of the bacteria to the extracts was evaluated by the well diffusion method and the inhibition parameters of the bacterial growth were determined by the micro-dilution assay according to the directives of document M27-A9 (2012) of the Clinical and Laboratory Standards Institutes (CLSI). The Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal concentrations (MBC) obtained were between 1.56 and 25.00 mg/ml. Stem-barks ethyl acetate extract from the East region, was most active on S. aureus, S. typhi and P. mirabilis with a MBC of 6.25 mg/ml. The leaves methanolic extracts from the center region was the most active with a MBC of 6.25 mg/ml on S. aureus. The ratio MBC/MIC shows that the majority of the extracts were bacteriostatic on the strains tested. The phytochimical screening revealed that the plant contained bioactive substances such as phenols, tannins, flavonoids, steroids, alkaloids, saponins, triterpenes and cardiac glycosides, reported by several authors for their antibacterial activity. The results obtained validate the traditional use of this plant in the treatment of affections of bacterial origin. Key words: Cameroon, Baillonella toxisperma (Pierre), bioactive substances, antibacterial activity.

In vitro antibacterial activities of extracts and fractions from two Cameroonian pharmacopeia plants, Carapa procera (Meliaceae) and Moringa oleifera (Morigaceae) were evaluate on five gastroenteritis-causing bacteria. The crude extracts of leaves and barks of Carapa procera (Meliaceae) as well as the seeds and leaves of Moringa oleifera (Morigaceae) were obtained in methylene chloride/methanol (1/1) by maceration. Phytochemical screening was done on the crude extracts by colorimetric tests. The crude extracts and their fractions were tested against five (5) bacterial species ( Salmonella typhi, Salmonella paratyphi, E. coli, Campylobacter jejuni and Bacillus cereus ) using the diffusion method on wells. The inhibition parameters were determined by the macro-dilution method in liquid medium and by the dilution method incorporated in agar for the determination of the Minimal Inhibition Concentration (MIC). The Minimal Bactericidal Concentration (MBC) was determined after subculture. The phytochemical screening revealed that, all plant extracts contain not only phenolic compounds (phenols, tannins and flavonoids), but also alkaloids, triterpene, sterols and lipids. The crude extracts and methanolic fractions of the leaves and barks of C. procera and the extract of seeds of M. oleifera were active against four (4) bacterial species: S. typhi, S. paratyphi, E coli and B. cereus . Concisely, the diameter of inhibition of these active fractions ranges between 10 and 26 mm for extracts concentration of 80 mg/ml. The active extracts and fractions gave MIC range from 2.5 to 10 mg/ml. The results obtained indicate that the seeds of Moringa oleifera (Morigaceae) and the barks of Carapa procera (Meliaceae) extracts as well as its methanolic fraction showed a bactericidal activity on four (4) sensitive species. Thus, the antibacterial properties of the extracts and fraction of those plants confirm their use in traditional medicine.

An ethnopharmacological survey concerning medicinal properties ofBaillonella toxisperma (Pierre) was carried out by interview with the indigenous population of Dimako village situated in the East region of Cameroon.The result showed that the plant is implicated in the treatment of many infections among which is fungal infections.To confirm the antifungal property of B. toxisperma (Pierre), the barks and leaves of the plant were collected and serial extractions in water, hydro-ethanol mixture (3:7), ethanol, methanol and ethyl acetate were performed in vitro.One part of the hydro-ethanol (3:7) extract was degreased by mixing in water-hexane mixture (1:1).The extracts were then tested in vitro against Candida albicans, Candida parasilopsis, Candida sp.responsible for superficial, deep or systemic mycosis and against Cryptococcus neoformans responsible for sub-acute meningitis in immunodeficient individuals.The susceptibility of yeasts to plant extracts was evaluated using the wells diffusion method and yeasts growth inhibition parameters were evaluated according to the proposed National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 standard guidelines (2002).The minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) determined were between 0.93 and 30.0 mg/ml.The extracts were fungicidal on clinical yeasts tested with MFC/MIC ratio of 1 or 2. The hexane phase HT2 from the hydro-ethanol crude extract of the barks gave the best antifungal activity on C. neoformans, with a MIC of 0.93 mg/ml and a MFC of 1.87 mg/ml.This activity was similar to the one obtained with fluconazole.Phytochemical screening revealed the presence of polyphenols, phenols, tannins, flavonoids, steroids, alkaloids, saponins, phlobatannins, triterpenes, anthocyanins, cardiac glycosides, leucoanthocyanins and fats, which are bioactive substances.The results could explain scientific validation to the traditional medical uses of B. toxisperma (Pierre) to treat fungal infections.

*Corresponding Author: E-mail: fankemhenri@yahoo.fr Tel: (+237) 699 83 89 69; 671 38 23 56. Phosphate solubilising bacteria (PSB) is an alternative for increasing the availability of accumulated phosphates through solubilisation, enhancing plant growth by increasing the efficiency of biological nitrogen fixation. Phosphate solubilising bacteria from acidic soils of Cameroon were screened for their phosphate solubilising ability on plate cultures containing inorganic/organic phosphates including calcium-phosphate (Ca3(PO4)2), aluminium-phosphate (AlPO4), iron-phosphate (FePO4), sodium-phytate as well as rock phosphates (RP) of different origins (Mali, Mexico and Morocco). They were subsequently tested on common and soya bean grown in pots filled with non-sterile and sterile soils amended with Malian rock phosphate for their aptitude in promoting plant growth and nodulation. The average index of solubilisation of the tested bacterial strains were 3.43 for calcium phosphate, 6.6 for aluminium phosphate, 4.12 for iron phosphate and 2.59 for sodium phytate. The index of solubilisation of the natural rock phosphates ranged from 1.33-2.71 with an average of 2.01. Enterobacter sp. was the only strain showing halo zone on plates with all the different insoluble phosphates. Based on the average effect of inoculation on growth and nodulation, Pseudomonas sp. was the strain showing the greatest result among the single inoculation treatments with an average of 251% for common bean, while Enterobacter sp. was the strain showing the greatest result among the single inoculation treatments with an average of 231.4% effect for soya bean plants. In both cases, the consortia BCD (Pseudomonas sp.+ Burkholderia sp.+ Enterobacter sp.) were the best among the different cocktails with an average of 162.5% and 197% for common and soya bean respectively. These results suggest that the use of rock phosphate combined with the co-inoculation of phosphate solubilising bacterial strains in soil with low fertility provides a sustainable alternative to the use of industrial fertilisers for both common and soya beans production.

Bovine tuberculosis is still prevalent and under-evaluated in cattle destined for human consumption in Cameroon. Potential reservoirs of the disease include livestock imported from countries endemic for bovine tuberculosis, such as Nigeria and Chad, and potential residual reservoirs in local livestock and wildlife. Few studies have been done in Cameroon to genotype the Mycobacterium tuberculosis complex (MTC) strains responsible for bovine tuberculosis. The aim of this work is to describe the population structure of MTC strains isolated from cattle, using spoligotyping as the genotyping method. Out of 218 organs or tissues from cattle with suspected tuberculosis lesions, 90 MTC strains were isolated and underwent molecular typing; among them, 86 strains were identified as M. bovis and four strains as M. tuberculosis. The M. tuberculosis strains belonged to rare M. tuberculosis lineages of the U family; among the M. bovis strains SB0944 was the most prevalent. Eight new spoligotype patterns were identified, representing 33% (30/90) of all isolates. Among these new spoligotypes, SB1955 was dominant. The spoligotype patterns of 85 M. bovis strains lacked spacer 30, a common characteristic of the M. bovis lineage African 1, described earlier in Cameroon, Chad, Mali and Nigeria. This study shows ongoing tuberculosis transmission involving M. bovis lineages not previously described as the leading cause of disease. It also shows a possible reverse zoonosis from humans to cattle.

Background: Many fungal infections are responsible for human skin damages, to control their negative action, some aromatic and medicinal plants are traditionally used by local population in Cameroon. The present study was carried out to determine the chemical composition of essential oils of Eugenia caryophylla and Mentha sp cf piperita and their antifungal activity on some human pathogenic fungi. Materials and methods: Essential oils from Eugenia caryophylla and Mentha sp cf piperita were extracted by steam distillation using Clevenger apparatus and the antifungal activity was evaluated on six human pathogenic fungal strains; two yeasts (Candida albicans 1 and Candida albicans 2) and four dermatophytes (Tricophyton rubrum 1, T. rubrum 2, T. violaceum, and T. soudanensis) using modified broth microdilution method M27-A3 and M38-A respectively. Results: The essential oils obtained yielded of 5.9 for Eugenia caryophylla and 0.2% Mentha sp cf piperita respectively. The chemical composition was assigned by GC and GC/SM and showed that E. caryophylla was mainly composed of eugenol (80.0 %), -caryophyllene (8.3%), and eugenol acetate (6.7%) while Mentha sp cf piperita was characterized by piperitone (67.5 %), menthol (10.0 %) and ß-phellandrene (5.8%). The result showed that essential oil of E. caryophylla exhibit the highest antifungal activity with MICs and MFC of 0.25µL/mL and 0.125µL/mL for filamentous fungi and MIC of 0.5 µL/mL for both yeast strains while MFC value was 1 µL/mL for one yeast strain and not determined for the second. MFCs Mentha sp cf piperita essential oil showed a weak activity with a MIC of 2.5 µL/mL on Tricophyton strains while no activity was exhibited on Candida albicans strains. Conclusion: The results of this work can be used to confirm their traditional uses and can also be proposed as natural ingredients to some industries to treat superficial infections.

Arbuscular mycorrhizal fungi (AMF) and members of the genus Trichoderma have emerged as promising groups of microbial inoculants that can induce plant growth and resistance to disease. This study aimed at investigating the potential of AMF and a strain (PR11) of Trichoderma asperellum to promote cacao growth and induce resistance against Phytophthora megakarya. Cacao seedlings were either non-inoculated, or inoculated with the saprophytic fungus T asperellum and/or a mixture of two different mycorrhizal fungi, Gigaspora margarita and Acaulospora tuberculata. Eighteen weeks after planting, a series of morphological as well as biochemical changes, which are considered to be part of the plant defense response, were measured after a challenge inoculation of the leaves with zoospores of P. megakarya. Inoculation with AMF and T. asperellum alone was essential for the promotion of plant growth. Significant increase in plant height, root and shoot fresh weights, as well as phosphorous uptake was recorded in comparison to non-inoculated control plants. However, dual inoculation of cacao seedlings with T. asperellum and AMF did not always positively benefit the plants. Leaf inoculation showed variation among the treatments, with the lowest disease index (highest level of resistance) recorded in plants inoculated with either AMF or T asperellum only. This came along with a high synthesis of amino acids and phenolic compounds in both healthy and infected leaves, suggesting that these metabolites are implicated in disease resistance. (C) 2011 Elsevier Ltd. All rights reserved.

A trial of a screening and selection strategy for phosphate-solubilizing bacteria based on phosphate solubilization ability, and the subsequent effect of these bacteria on plant growth promotion under in situ conditions, was conducted. Of the 277 (187 from soils and 90 from roots) microorganisms tested, 10 bacteria (BOR8, LEJ14, DR5, DR9, EDJ4, EDJ6, EDJ8, SR7, EMJ5, LR7) were selected. All the bacteria were able to show P dissolution halo zone particularly on agar plates containing sparingly soluble iron phosphate as well as they were able to mobilize important amount of P in liquid media supplemented with either Ca3(PO4)2 or AlPO4·H2O or FePO4·2H2O. Calcium phosphate (Ca-P) solubilization resulted from combined effects of pH decrease and carboxylic acids synthesis. However, the synthesis of carboxylic acids was the main mechanism involved in the process of aluminium phosphate (Al-P) and iron phosphate (Fe-P) solubilization. Both nutrients were mobilized at pH 4 corresponding to their natural occurrence by citrate, malate, tartrate, on much lower level by gluconate and trans-aconitate. Subsequently, a greenhouse trial using cowpea and millet inoculated with selected bacteria showed a significant improvement of plant phosphorus uptake as well as root and shoot dry weight. However, the selection of phosphate-solubilizing bacteria as possible inoculation tools for phosphate-deficient soils should focus on the integral interpretation of laboratory assays, greenhouse experiments, and field trials.

In a greenhouse study we investigated the potential of wood ash amended composts to ameliorate acid tropical soils. Three composts (produced with 0%, 8% and 16% wood ash admixture, respectively), and two acid tropical soils, an Oxisol and an Ultisol from Cameroon were used for that purpose. In this paper we report the effects on the soil microbiota at the end of the cropping cycle (100 days soybean plus 100 days fallow). Principal coordinate analysis of denaturing gradient gel electrophoresis patterns of ammonium oxidizing bacteria (AOB) indicated that they were stimulated by addition of compost. AOB communities of the compost treated soils differed from the control ones, and no significant differences among the different composts were found in both soils. Soil type clearly influenced the AOB community. Ester-linked phospholipid fatty acids increased in compost treated soils, up to an ash amendment of 8%. The ratio of cyclopropyl-to-monoenoic precursor (cy19:0 to 18:1 omega 7), which has been proposed as an indicator of stress conditions, decreased upon compost addition and did not differ among the treated soils. Community level physiological profiling indicated an increase in activities after addition of compost, the effect was most distinct for the compost with 16% ash.Based on these results, compost with moderate close of wood ash is considered beneficial to the soil microbiota and could thus be used for ameliorating tropical acid soils. (C) 2010 Elsevier B.V. All rights reserved.