Cameroon Journal of Experimental Biology

Acknowledgements (2021-2022)

2023-10-05T16:50:41+00:00

Reviewers of the period from January 2021 to December 2022

Evaluation des structures locales de stockage des grains et des graines dans le Département des Bamboutos, Cameroun

2022-10-02T20:01:38+00:00

Post-harvest food losses remain a major problem in sub-Saharan Africa. A study of local storage structures aimed at carrying out a diagnostic analysis of post-harvest losses in grains and seeds in the Bamboutos department, West region, Cameroon. A questionnaire survey was carried out among 240 producers in 12 villages, spread over 3 subdivisions. Air temperature and relative humidity data were collected over 80 days at two storage stores in this study area. Twelve samples of food infested by insect were taken and deposited in the entomology laboratory of the Faculty of Agronomy and Agricultural Sciences at Dschang University for identification. It emerges from this investigation that corn is the only grain stored by producers. Beans and peanuts are mostly stored seeds, while pistachios and soybeans are seeds stored by few farmers. Three structures are used for grain storage: granaries (86.25%), cribs (10.42%) and stores (3.33%). Among the containers, two are mainly used for seed storage: barrels (58.38%) and bags (39.25%); buckets with lids are used by a few farmers (2.36%). The storage period of corn is between 8 and 12 months. The storage period of peanuts is between 6 and 8 months and beans between 4 and 5 months. The use of chemicals, inert matter (ash) and plant substance (neem) are the three methods of protection used in Bamboutos. Bamboutos storage stores promote the development of molds and insects. Three major groups of biological agents are responsible for spoilage: insects (Callosobruchus maculatus F., Sitophilus zeamais M. and Acanthoscelides obtectus S.), rodents (Rattus norvegicus, Rattus rattus and Mus musculus) and molds. Insects are the pests that cause the most damage to stored products according to 55.42% of producers. According to 23.58% of producers, it is rodents and 15% molds. Farmers estimate that the damage to the stock is between 7% and 30% after destocking of maize. This damage is between 2% and 5% after removal of beans from storage and less than 3% after removal of peanuts. Farmers underestimate the damage caused by pests on corn, which is around 40% after 10 months of storage in granaries. It is therefore essential for Cameroonian farmers to master and respect the storage techniques according to the storage structures and the foodstuffs stored.

Antioxidant and antibacterial activities of constituents and hemi-synthetic derivatives from Senna siamea (Lam.) H. S. Irwin & Barneby (Caesalpiniaceae)

2023-02-05T21:58:11+00:00

Eleven compounds (1-11) were isolated from the methanolic extract of leaves and bark of Senna siamea. Benzylation of compound 2 gave two new hemi-synthetic derivatives: 4'-O-benzylvitexin (12) and 7,4'-O-dibenzylvitexin (13). The structures of these compounds were established on the basis of their spectroscopic (1D and 2D NMR) and mass spectrometric (FAB-TOF-MS) data. The extracts, fractions, some of the isolated compounds as well as hemi-synthetic derivatives were evaluated for their antibacterial activity using broth microdilution method. They were also tested for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging potential and ferric reducing antioxidant power (FRAP). The ethyl acetate fraction of the stem bark showed moderate activity) against E. faecalis and P. mirabilis with MIC value of 256 μg/mL. Compound 6 showed moderate activity toward P. mirabilis (MIC = 64 μg/mL). The methanolic extract from bark (EC50 = 1.58 ± 0.25) μg/mL, its ethyl acetate (EC50 = 1.12 ± 0.67) μg/mL and n-BuOH fractions (EC50 = 1.02 ± 0.87) μg/mL as well as n-BuOH fraction from leaves (EC50 = 1.24 ± 0.33) μg/mL were more active against DPPH compared to vitamin C. Compound 4 was the most active against DPPH (EC50 = 1.05 ± 0.38) μg/mL.

Propagation, development phases and domestication of Cyperus rotundus L. in the Western Highlands of Cameroon

2023-01-24T07:32:42+00:00

Cyperus rotundus Linn. is a potentially valuable aromatic plant given its ability to synthesise essential oil and the variety of traditional uses associated with it. The valorisation of this plant would imply the exploitation of a significant quantity of its biomass, which cannot be obtained from the wild. The aim of this study was to determine the best methods for regeneration and the development phases of C. rotundus, in order to ensure the continuous availability of its biomass.

The mode of natural regeneration and the state of domestication of C. rotundus by local populations were investigated through surveys of traditional healers and herbalists. In addition, ex situ regeneration trials were carried out using vegetative propagation from bulbs and seed germination. The vegetative propagation was assessed by estimating the lag time and percentage regeneration of the bulbs, while the seed germination percentage was evaluated. The development phases of the plant were identified following the BBCH (Biologische Bundesanstalt Bundessortenamt and CHemische Industrie) scale. The yield was calculated from the underground biomass of the bulbs produced at the end of the plant life cycle.

The results showed that C. rotundus regenerates naturally from bulbs and rarely from seeds. In the Western Highlands of Cameroon, traditional practitioners and herbalists have begun domesticating C. rotundus on a small scale. Propagation attempts from seed were unsuccessful in the present study. However, from bulbs, a lag time of 10 days was observed and a regeneration percentage of 88% obtained after 47 days. Five phases of development were identified including emergence (0), bolting (1), flowering (2), maturation (3) and senescence (4). The production of bulbs, which are organs containing the essential oils, was observed from the bolting phase. The biomasses of about 383, 493 and 520 kg/ha were obtained during phase 1, 2 and 3 respectively.

The best propagation method and the development phases of Cyperus rotundus investigated in this work could contribute to an advance in the domestication process in order to ensure its availability and sustainability.

Effects of combined mineral and sewage sludge fertilization on soil properties and growth of two Zea mays (L.) varieties in Western Highlands of Cameroon

2023-06-14T01:04:05+00:00

This study aimed at evaluating the effects of combined application of dewatered sewage sludge (SS) and mineral fertilizer on the chemical properties of the soil and growth of Zea mays. Six treatments: T0, negative control; T1, positive control of 120 kg N/ha; T2, 2 t/ha sewage sludge (SS) + 60 kgN/ha; T3, 4 t/ha SS + 60 kgN/ha; T4, 8t / ha SS+ 60 kgN/ha and T5, 8 t/ha SS were applied in completely randomized block experimental design. The following parameters: height of plants, diameter of stem, number of healthy leaves, leaves area index, root and shoot biomasses were measured on plants at 30, 44 and 58 days after sowing. For the soil parameters, electrical conductivity (EC), redox and hydrogen potentials were measured at the same frequency. The results showed that the height, the stem diameter, the number of leaves, the leaves area index and the biomass of Zea mays increased in response to soil supplementation with sewage sludge combined with mineral fertilizers. The treatment that best stimulated the growth of maize was T4 (8t/ha SS+ 60 kgN/ha). The soil chemical properties were modified by sewage sludge application. In general, pH and conductivity decrease with sludge application, while, redox potential increased. This shows that combined sewage sludge to NPK (20 10 10) leads to changes in chemical parameters of the soil and thus, influencing the nutrients uptake by plants to improve their growth.

Inventaire préliminaire des Chiroptères réservoirs des infections en République de Guinée : Boké, Conakry, Faranah, Mamou, Kindia et N’zérékoré

2023-04-27T13:05:57+00:00

The aim of this work is to make a preliminary inventory of chiropteran reservoirs of infection in the Republic of Guinea: Boké, Conakry, Faranah, Mamou, Kindia and N'zérékoré. The study was conducted from January 1, 2016 to December 31, 2019. One thousand chiropterans were captured with fishing nets, mist nets or by hand and divided into 18 species and 6 families. Identification was based on the reference collection of IRBAG, Rosevear DR, Hayman RW and Bergmans W.The most representatives were: Hipposideros caffer (15.5%), Mops condylurus (10.8%), Nycteris hispida (7.7%), Neoromicia guineensis (6.8%), Hipposideros jonesi (6.3%), Chaerephon nigeriae (4, 9%), Rhinolophus guineensis (4.2%), Chaerephon pumillus (3.3%), Eidolon helvum (2.6%), Epomophorus gambianus (1.9%), Hipposideros abae (1.3%). On the other hand, the least encountered are: Scotophilus diganii (0.8%), Lissonycteris angolensis (0.7%), Rhinolophus alcyone (0.5%), Rousettus aegyptiacus (0.4%), Scotophilus leucogaster (0.4%) and Neoromicia brunnea (0.2%). These species represent the bulk of the chiropterans fauna, which may play an epidemiological or predatory role for crops and harvests.