Papers by Paul Alain NANA
Morphology and infraciliature of two new earthworm ciliates, Hoplitophrya polymorphus sp. nov. an... more Morphology and infraciliature of two new earthworm ciliates, Hoplitophrya polymorphus sp. nov. and Anoplophrya simplex sp. nov. Abstract Morphological and infraciliature studies carried out using pyridinated ammoniacal silver carbonate and the 4',6-diamidi-no-2-phenylindole (DAPI) staining techniques, led to the identification of two new species of ciliates pertaining to the subclass Astomatia. The first species, Hoplitophrya polymorphus sp. nov., displays two main cellular forms: the elongated form (150–247 μm long and 40–87 μm width) and the stocky form (140–170 μm long and 70–98 μm width). The macro-nucleus is generally skinny in the elongated forms and ribbon-shaped in the stocky forms. The common feature of the two cellular shapes uniting them in the same species is the identical structure of their skeletal apparatus, a V-shaped element located in an apical depression and bearing skeletal fibres on its ventral face. The second species, Anoplophrya simplex sp. nov., is totally deprived of skeletal apparatus. The cell shape is fusiform and dorsoventrally flattened (105–180 μm long and 65–125 μm width). Six to 12 pulsatile vacuoles form two rows arranged symmetrically on either side of the ma-cronucleus. These two newly identified species highlight the extremely rich diversity of ciliates inhabiting the digestive tract of tropical earthworms.
The intestinal liquid of A. emini was extracted using the vacuum aspiration technique, followed b... more The intestinal liquid of A. emini was extracted using the vacuum aspiration technique, followed by measurement of ion concentrations and concomitantly recorded species abundance. Nitrate (NO 3-) concentration decreased from the foregut to the hindgut. Nitrites (NO 2-), ammoniums (NH 4 +) and orthophosphates (PO 4 3-) reached their greatest levels in the midgut. Furthermore, correlation analyses between ion contents and ciliate abundance in different compartments were performed. In the foregut, a positive and significant correlation was found between the abundance of the Paracoelophrya ebebdensis and PO 4 3-. In the midgut, a positive and significant correlation was observed between the number of the ciliates Dicoelophrya mediovacuolata; Coelophrya roquei; Coelophrya ovales; Ptychostomum commune and NO 2-; Almophrya mediovacuolata and NH 4 +. In this same compartment, a positive and significant correlation was also observed between the abundance of Ptychostomum prolixus and NO 2-. In the hindgut, a positive and significant correlation was found between the values of PO 4 3-and Ptychostomum variabilis abundance. These results suggest that each portion of the digestive tract of A. emini can be considered as a set of natural micro-habitat in which a large number of ions generate ecological niches suitable for the Survival of a specific group of ciliate species.
The flow cytometry technique, based on the enumeration and multi-parametric analysis of suspended... more The flow cytometry technique, based on the enumeration and multi-parametric analysis of suspended particles in a liquid medium, has enabled us to identify an population of viruses and bacteria in the soil and the digestive tract of earthworms. It appears that the passage of the ground through the digestive tract of oligochaetes annelids would regulate bacterial and viral biomass of the soil as well as soil physico-chemical parameters. The soil microfauna is involved in the decomposition of the organic material and the nutrient bioavailability to plants and soil microorganisms. It also plays an important role in the creation and conservation of the soil structure. Apart from their role as "engineers", earthworms through their internal microfauna, participate in the regulation of physical and chemical parameters such as nitrogen mineralization. Earthworms thus participate in the processes of decomposition of organic material improve the bioavailability of minerals, maintain the porosity of the soil and increase the stability of the aggregates. Oligochaetes are expected to play a central role in the implementation of biological regulation in the agro-ecosystems essential to the development of ecological and intensive agriculture. Another reason to be interested in these soil organisms is that they are good candidates for bio-indicators. Indeed, the level of their population is sensitive to cultural practices, chemical products that are spread, quality and quantity of the resource in carbon, which are important characteristics of the sustainability of agricultural systems.
The paper demonstrates the influence of physico-chemical parameters on the distribution of endoco... more The paper demonstrates the influence of physico-chemical parameters on the distribution of endocommensal ciliates through the gut of the earthworm Alma emini. We measured physico-chemical parameters of the intestinal liquid extracted with the vacuum aspiration technique and concomitantly recorded biological parameter (species abundance). Furthermore, correlation analysis between physico-chemical parameters and biological parameter was performed in different compartments. In the foregut, among the eleven species of Astomatia recorded, correlation was significant between Metaracoelophrya intermedia, Coelophrya roquei and Water Content (WC = 46.94 ± 7.77%). In the midgut, among the nine species of Hysterocinetidae recorded, a significant correlation was observed between Metaptychostomum ebebdae, Ptychostomum macrostomum and Electric Conductivity (EC = 84.55 ± 12.94 µS/ cm). In the same compartment, a significant correlation was also observed between Ptychostomum macrostomum and Total Dissolved Substance (TDS = 16.20 ± 3.46%). In the hindgut, eight species of Astomatia were found, among which significant correlation was obtained between Coelophrya roquei and Hydrogen potential (pH = 7.35 ± 0.16). In the same compartment, taking into account the eleven species of Hysterocinetidae recorded, a significant correlation was also obtained between Ptychostomum macrostomum and pH; Ptychostomum commune and WC (28.84 ± 3.97%). These results suggest that each part of the digestive tract of A. emini can be
Studies on five new species of hysterocinetian ciliates, endocommensal within a terrestrial oligo... more Studies on five new species of hysterocinetian ciliates, endocommensal within a terrestrial oligochaete from the genus Alma (Cameroon), reveal the existence of three distinct types of cytoskeletal topography within their adhesive apparatus. In the first topographical type, four superimposed antagonistic strata of skeletal fibres that correspond to the arrangement observed in the genus Ptychostomum, Stein 1860 are found. The second topographical type is characterized by the existence of an unorganized field of fibrillar structures forming a single dense mass in the central part of the sucker. For this, a new genus is created: Ptychostomoides, Nana, Fokam, Ntoungwa et al. n. g. The third type present in the genus Proptychostomoides, Nana, Fokam, Ntoungwa et al. n. g. differs from the latter by the existence of a bare patch within the central region of the adhesive apparatus. This new evidence of morphological diversification within the Hysterocinetidae supports a new approach to the systematics of this group.
Today, rice has become one of the most consumed cereals in Africa in general and Cameroon in part... more Today, rice has become one of the most consumed cereals in Africa in general and Cameroon in particular. The low domestic production imposes a strong import that accentuates the country's trade imbalance. To reduce this issue of external dependency, the national government is encouraging domestic production. However, producer's efforts are inhibited by various constraints among which the pest attacks in general and in particular the stem borers. Data collection was based on sampling and incubation of white rice panicles in an experimental plots set up at Nkolbisson, Yaoundé. The susceptibility of rice varieties to different pest species was evaluated by comparing the frequency of pest species on their infested panicles. Among the NERICA rice lines, NERICA 3 had the greatest percentage of attacks panicles that was 41.96 % while NERICA 9 and 13 had the less percentage of attacks panicles that was 14.29 % for both of them. A total of three pest species were identified from the panicles incubated, Orseolia oryzivora, Chilo zacconius and Diopsis apicalis, O. oryzivora being the most frequent. NERICA 3 with 41.96% of incubated panicles appears to be the most susceptible variety, while the Japanese's Akitakomachi and Fukuhibiki showed no attack. These results are discussed in relation to the total sugar content and polyphenol in different rice varieties studied.
The performances were evaluated primary branches balls per panicle. NERICA's varieties from Afric... more The performances were evaluated primary branches balls per panicle. NERICA's varieties from Africa. rice plant was very high (a mean of Orysa in both African and Japan rice studied. between the NERICA between results suggest
Five new species belonging to the astome ciliates, living in the digestive tract of Oligochaeta w... more Five new species belonging to the astome ciliates, living in the digestive tract of Oligochaeta worms belonging to the genus Alma from Cameroon, have been described. The techniques used are: vital staining, staining of the nucleus with Diamidino Phenyl Indol (DAPI), scanning electron microscopy and silver staining method (Fernandez Galiano, 1976, 1994). This work confirms the presence of the genus Paracoelophrya and Dicoelophrya in the digestive track of the oligochaete Alma from Gabon and Cameroon; it helps to understand the general taxonomy of this Metaracoelophryinae subfamily. Moreover, the homogeneity of this group is confirmed and the phylogenetic relationship inside the Hoplitophryida order need more studies to be solved. Résumé : Cinq nouvelles espèces de ciliés astomes, présentes dans le tube digestif de vers oligochètes du genre Alma du Cameroun, ont été décrites. Les techniques utilisées sont : l'observation vitale, la coloration au DAPI, la microscopie électronique à balayage et les imprégnations argentiques selon Fernandez Galiano, 1966. Ce travail confirme la présence des genres Paracoelophrya et Dicoelophrya dans le tube digestif des oligochètes du genre Alma du Gabon et du Cameroun ; il permet de faire une synthèse récapitulative de la sous-famille des Metaracoelophryinae. De plus, est confirmée l'homogénéité de ce groupe, et est reposée la question de la parenté phylogénétique des Hoplitophryida.
Two new species of astomatous ciliates (Dicontophrya minus n. sp. and Dicontophrya ebebdaensis n.... more Two new species of astomatous ciliates (Dicontophrya minus n. sp. and Dicontophrya ebebdaensis n. sp.) endocommensal of Glossoscolecidae earthworms pertaining to the genus Alma are described using light-microscopy and a combination of staining techniques (pyridinated ammoniacal siver nitrate and DAPI). Studies reveal the existence of two distinct morphological types as evidence of morphological diversification within the genus Dicontophrya de Puytorac and Dragesco, 1969. In the first morphological type represented by Dicontophrya minus n. sp., the cell is ovoid (90 x 125 – 35 x 115 µm) with a ribbon like axial macronucleus flanked with a relatively big micronucleus (6.2 µm in diameter). In the second morphological type (Dicontophrya ebebdaensis n. sp.), the cell is elongated and wormlike (180 x 215 – 35 x 50 µm) with a nuclear apparatus composed of a long ribbon shape macronucleus (171.1 µm), bearing in its posterior half a globulous micronucleus. In the two cases cells bear in the anterior end a depression in which lodges a skeletal apparatus build in the same plan of organization (a modified V shaped skeletal branch bearing about 7 skeletal fibers) that characterize the genus.
ARTICLE INFO ABSTRACT Soil containing the earthworms (Fokam, 2012, was dug monthly for six months... more ARTICLE INFO ABSTRACT Soil containing the earthworms (Fokam, 2012, was dug monthly for six months. Worms where counted in situ to establish earthworm's volumic density (VD) and subsequently dissected to evaluate cil Ten soil physicochemical parameters were analyzed: Cation Exchange Capacity (CEC), Mg Available Moisture (M), and pH. The studies reveal for Dicoelophrya nkoldaensis and physicochemical parameters demonstrated a significant negative correlations with TN (r = P < 0, 05), AP (r = 05). In the mid gut, a significant positive correlation with (M) (r = 0.356; P < 0, 05), a highly significant positive correlation with Ca correlation with TN (r = observed with TN (r = 0.456; P < 0, 05). Correlations of soil physico highly significant positive correlation with CEC (r = 0.634; P < 0, 01) and Mg a significant negative correlation with both OC (r = and a significant positive correlation with potassium (r = 0.350; P < 0, 05). These results suggest that the preferential zone of a microhabitat, is influenced by the physicochemical parameters of the soil ingested.
The morphology and ciliature of four Nyctotherus species (Nyctotherus orthostomatus n. sp., Nycto... more The morphology and ciliature of four Nyctotherus species (Nyctotherus orthostomatus n. sp., Nyctotherus ndoumeleleensis n. sp., Nyctotherus ngassami n. sp. and Nyctotherus atunibaensis n. sp.), isolated from the mid and hindgut of a Megascolecidae annelid of the genus Eupolytoreutus from the northwest region of Cameroon, were investigated using living observation (methylene blue) and silver impregnation methods (Fernandez-Galiano, 1994). Nyctotherus orthostomatus n. sp. is recognized by a pear-shaped body (128-152 × 95-104 µm); a conspicuous buccal apparatus with the peristome and the infundibulum perpendicular to each other; about 41-46 somatic kineties covering each side of the cell; one transversally elongated massive macronucleus located in the anterior third of the cell, surmounted by a very small spherical micronucleus. Nyctotherus ndoumeleleensis n. sp. is distinguished by the combination of the following characters: ovoid body (151-163 × 87-92 µm) with rounded poles; about 52-68 somatic kineties uniformly covering the cell body; an anterior, transversal and trapezoidal macronucleus carrying laterally a small micronucleus (2-3.5 µm in diameter). Nyctotherus ngassami n. sp. can be distinguished from its congeners by the following set of features: size about 153-269 × 102-148 µm; body ovoid, with 64-86 ciliary rows covering its surface; a small and globular micronucleus hidden by a transversal macronucleus located slightly above the equatorial part of the cell. Nyctotherus atunibaensis n. sp. is characterized by size about 145-253 × 95-162 µm, ovoid cell body, 108-122 somatic kineties, · 63 Protistology a transversal and arc-shaped macronucleus hiding a small micronucleus. In the present study, new locality (northwest region of Cameroon) and new species of the genus Nyctotherus are explored.
This study was devoted to accessing the influence of some soil physico-chemical parameters on the... more This study was devoted to accessing the influence of some soil physico-chemical parameters on the abundance of Almophrya mediovacuolata Ngassam, 1983, astome ciliate of the digestive tract of earthworms (EW) of the species Alma nilotica collected along " Fa'a ntsa " stream in Bambui. The survey primarily involved soil samples collection from the same spots of EW collection and preparation for physico-chemical analysis; evaluation in situ of the volumic density (VD) of worms (number /dm 3 soil), their dissection, isolation and counting of ciliates with respect to different portion of EW's gut (fore, mid and hindgut). Furthermore, correlation analysis between soil physico-chemical parameters and biological responses (EW volumic density and ciliate abundance) were performed. The results reveal that EW abundance was positively and significantly correlated with the following physico-chemical parameters: Cation Exchange Capacity CEC (p <0.01) and Mg 2+ (p <0.05). A positive and significant correlation was found between Almophrya mediovacuolata and the pH of KCl in the foregut and midgut (p <0.01) while a negative and significant correlation was found between the abundance of Almophrya mediovacuolata and Ca 2+ in the foregut (p <0.05). Almophrya mediovacuolata were found mostly in the foregut. This result shows that each portion of the digestive tract of Alma nilotica can be considered as a set of natural microhabitat in which a number of physico-chemical factors generate ecological niches suitable for the survival of different species of microorganisms among which ciliated protozoa. The fore and midgut was noticed to be the preferential zones of Almophrya mediovacuolata.
Earthworms of the genus Alma nilotica belonging to the family Glossoscolecidae, lodges an abundan... more Earthworms of the genus Alma nilotica belonging to the family Glossoscolecidae, lodges an abundant fauna of astomatous ciliates in its digestive tract. Each species is located in a well-defined portion of the gut and the reasons for this stratification still remain unclear. In order to assess the influence of physico-chemicals parameters of the soil on the distribution of one of these astomatous ciliates (Paracoelophrya polymorphus Fokam, 2012) along the digestive tract of Alma nilotica, a study was carried out from April to September 2013 in Bambui on the banks of Fansaah river. The volumic density (VD) of worms (number /dm 3 soil) was examined. A total of 60 worms were used for the counting of ciliates. The observation of Paracoelophrya polymorphus was done after staining with methylene blue. Twelve physico-chemicals parameters of the soil from the site of collection of worms were analyzed. The degree of binding between the VD of worms, the abundance of ciliates and physico-chemicals parameters was performed for different portions of the digestive tract. VD of the earthworms shows a positive and significant correlation with the Cation Exchange Capacity CEC (r = 0.771; P < 0, 05) and with Mg (r = 0.886; P < 0, 01). Paracoelophrya polymorphus is located in the foregut and midgut of its host but, its preferential zone is the foregut. In the foregut, a negative and significant correlation was found between available phosphorus (P) and P. polymorphus abundance (r =-0,943; P < 0, 01). In the midgut, a positive and significant correlation was obtained between the Cation Exchange capacity (CEC) (r = 0.754; P < 0, 05), magnesium (r = 0.812; P < 0, 05), calcium (r = 0.754; P < 0, 05) and P. polymorphus abundance. These chemical parameters influence directly the density of the earthworms and indirectly the stratification of P. polymorphus.
Prosicuophora cyclostomatus n. sp. and Nyctotheroides bambuiensis n. sp. are two new ciliate spec... more Prosicuophora cyclostomatus n. sp. and Nyctotheroides bambuiensis n. sp. are two new ciliate species isolated from the rectums of Bufo regularis collected in the vicinity of Bambili and Bambui. The morphological characteristics of these Protozoa are described and their relation to similar species is discussed.
Le monde de demain consommera « renouvelable » ou ne sera plus. Toutes les études le démontrent :... more Le monde de demain consommera « renouvelable » ou ne sera plus. Toutes les études le démontrent : l'efficacité énergétique constitue l'un des enjeux majeurs des prochaines décennies, et les pays du Sud, ceux de l'Afrique subsaharienne en tête, disposent d'un potentiel d'énergies durables inestimable. Au-delà de l'incessant débat Nord-Sud autour de la coopération énergétique, de l'aide au développement et des transferts de technologies, pourquoi ne pas s'intéresser aux initiatives des acteurs locaux, et encourager la jeunesse dans une démarche écocitoyenne ? C'est dans cette voie que s'est engagé l'Institut Français du Cameroun, en partenariat avec les associations Actions Vitales pour le Développement Durable (AVD) et MIEUX-ÊTRE, sous le haut patronage du Ministère des Enseignements Secondaires du Cameroun (MINESEC), en conduisant le projet « Jeunes Énergies Propres » (JEP). Une initiative pragmatique qui mise sur une citoyenneté environnementale à la base de la révolution énergétique… Paul alain NaNa Paul-alain Nana est titulaire d'un doctorat/Ph.d de l'université de Yaoundé au Cameroun dans la spécialité hydrobiologie et environnement. il effectue depuis 2016 un stage postdoctoral au laboratoire microorga-nismes : Génome et environnement (lmGe) à l'université Clermont auvergne (France). Éducateur environ-nemental et auteur de plusieurs articles scientifiques, le docteur Paul-alain NaNa est depuis l'année 2011, responsable des programmes au sein de l'oNG camerounaise actions Vitales pour le développement durable (aVd). enseignant contractuel à l'université des montagnes (ouest Cameroun), il a contribué au montage et à la mise en oeuvre de plusieurs projets de développement au Cameroun. il a également participé à plusieurs rencontres internationales sur les questions environnementales (biodiversité, écologie, eau et assainissement, développement durable, changement climatique, etc.). Jean-Paul aFFaNa Jean-Paul brice affana affana est instructeur de Jeunesse et d'animation, formé par le ministère camerounais de la Jeunesse. Ses centres d'intérêt et ses expériences comprennent le développement social, le changement climatique, le développement durable, le dialogue interculturel, la consolidation de la paix, l'autonomisation et le développement des jeunes et les droits de l'homme. Jean-Paul est le Coordonnateur de l'oNG « actions Vitales pour le développement durable » (aVd) dirigée par les jeunes depuis 2008. il a été le Point Focal des oNG de la Convention-Cadre des Nations unies sur les Changements Climatiques (CCNuCC) en 2011. il a travaillé avec la division des affaires de la jeunesse du Secrétariat du Commonwealth en tant que coordon-nateur du réseau des jeunes du Commonwealth sur le changement climatique. Jean-Paul est également responsable des programmes pour les jeunes de l'association internationale pour l'avancement des approches innovatrices des défis mondiaux (iaai), une organisation autrichienne ; en plus de sa participation à l'initiative pour la jeunesse africaine sur les changements climatiques.
Le monde de demain consommera « renouvelable » ou ne sera plus. Toutes les études le démontrent :... more Le monde de demain consommera « renouvelable » ou ne sera plus. Toutes les études le démontrent : l'efficacité énergétique constitue l'un des enjeux majeurs des prochaines décennies, et les pays du Sud, ceux de l'Afrique subsaharienne en tête, disposent d'un potentiel d'énergies durables inestimable. Au-delà de l'incessant débat Nord-Sud autour de la coopération énergétique, de l'aide au développement et des transferts de technologies, pourquoi ne pas s'intéresser aux initiatives des acteurs locaux, et encourager la jeunesse dans une démarche écocitoyenne ? C'est dans cette voie que s'est engagé l'Institut Français du Cameroun, en partenariat avec les associations Actions Vitales pour le Développement Durable (AVD) et MIEUX-ÊTRE, sous le haut patronage du Ministère des Enseignements Secondaires du Cameroun (MINESEC), en conduisant le projet « Jeunes Énergies Propres » (JEP). Une initiative pragmatique qui mise sur une citoyenneté environnementale à la base de la révolution énergétique… Paul alain NaNa Paul-alain Nana est titulaire d'un doctorat/Ph.d de l'université de Yaoundé au Cameroun dans la spécialité hydrobiologie et environnement. il effectue depuis 2016 un stage postdoctoral au laboratoire microorga-nismes : Génome et environnement (lmGe) à l'université Clermont auvergne (France). Éducateur environ-nemental et auteur de plusieurs articles scientifiques, le docteur Paul-alain NaNa est depuis l'année 2011, responsable des programmes au sein de l'oNG camerounaise actions Vitales pour le développement durable (aVd). enseignant contractuel à l'université des montagnes (ouest Cameroun), il a contribué au montage et à la mise en oeuvre de plusieurs projets de développement au Cameroun. il a également participé à plusieurs rencontres internationales sur les questions environnementales (biodiversité, écologie, eau et assainissement, développement durable, changement climatique, etc.). Jean-Paul aFFaNa Jean-Paul brice affana affana est instructeur de Jeunesse et d'animation, formé par le ministère camerounais de la Jeunesse. Ses centres d'intérêt et ses expériences comprennent le développement social, le changement climatique, le développement durable, le dialogue interculturel, la consolidation de la paix, l'autonomisation et le développement des jeunes et les droits de l'homme. Jean-Paul est le Coordonnateur de l'oNG « actions Vitales pour le développement durable » (aVd) dirigée par les jeunes depuis 2008. il a été le Point Focal des oNG de la Convention-Cadre des Nations unies sur les Changements Climatiques (CCNuCC) en 2011. il a travaillé avec la division des affaires de la jeunesse du Secrétariat du Commonwealth en tant que coordon-nateur du réseau des jeunes du Commonwealth sur le changement climatique. Jean-Paul est également responsable des programmes pour les jeunes de l'association internationale pour l'avancement des approches innovatrices des défis mondiaux (iaai), une organisation autrichienne ; en plus de sa participation à l'initiative pour la jeunesse africaine sur les changements climatiques.
We examined the relationship between viruses and co-occurring bacterial communities across spatio... more We examined the relationship between viruses and co-occurring bacterial communities across spatiotemporal scale in two contrasting freshwater lakes, namely meromictic Lake Pavin and dimictic Lake Aydat (Central France). Next-generation se-quencing of 16S rRNA genes suggested distinct patterns in bacterioplankton community composition (BCC) between the lakes over depths and seasons. BCC were generally dominated by members of Actinobacteria, Proteobacteria, and Bacteroidetes covering about 95% of all sequences. Oxygen depletion at the bottom waters in Aydat and existence of permanent anoxia in the monimolimnion of Pavin resulted in the occurrence and dominance of lesser known members of lake communities such as Methylotenera, Methylobacter, Gallionella, Sulfurimonas, and Syntrophus in Pavin and Methylotenera and Sulfuritalea in Aydat. Differences in BCC appeared strongly related to dissolved oxygen concentration, temperature, viral infection, and virus-to-bacteria ratio. UniFrac analysis indicated a clear distinction in BCC when the percentage of viral infected bacterial cells and virus-to-bacteria ratio exceeded a threshold level of 10% and 5, respectively, suggesting a link between viruses and their potential bacterial host communities. Our study revealed that in both the lakes, the prevailing environmental factors across time and space structured and influenced the adaptation of bacterial communities to specific ecological niches.
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Papers by Paul Alain NANA