Fruit Morphometric and RAPD Evaluation of Intraspecific Variability in Some Accessions of African Yam Bean (Sphenostylis stenocarpa Hochst. ex. A. Rich. Harms)

African Yam Bean (AYB) (Sphenostylis stenocarpa, Hochst. ex A. Rich, Harms) is an indigenous underutilized legume mainly grown in Sub-saharan African as a source of protein. Intraspecific variability studies were carried out on 10 accessions of AYB obtained from the International Institute of Tropical Agriculture (IITA) Ibadan, Nigeria. Fourteen (14) fruit morphometric characters and nine (9) arbitrary RAPD primers were employed for evaluation of genetic intra-specific variability among the accessions. A total of 410 bands were generated with 261 (63.66%) polymorphic bands. There is significant correlation among some reproductive characters; days to 50% flowering, pods per peduncle, number of locules per pod, number of seeds per pod, pod length and seed set percentage. These characters represent good markers of the taxon suitable for breeding and genetic improvement purposes. Morphometric and RAPD cluster analysis using UPGMA resulted in a dendrogram each; with membership similarity ranging from 72% to 93%. Two accessions (TSs56 and TSs94) recorded higher level of similarity index of 93% based on RAPD profiling. The morphometric evidences shows inherent stability of AYB across varied eco-geographical settings, which demands further investigation and exploitation. However, the RAPD evidences show that the species have evolved and adapted to distinct geographical setting with a clear Nigeria and Ghana demarcation. This fact can be engaged to guide future studies, germplasm collection, characterization, documentation, utilization and conservation of AYB to boost knowledge and awareness on the genetic diversity and utility of the species

Morphological Diversity and Cytological Studies in Some Accessions of Vigna vexillata (L.) A. Richard

Aim: The objectives of this study were to characterize and evaluate intraspecific relationship among twenty-six accessions of Vigna vexillata (L.) and work out interrelationship among the morphological traits which could be used for genetic improvement of cowpea, V. unguiculata (L.) Walp. Study Design: Field experiment was laid out in blocks of five buckets per accession in a row giving a total of 260 plants. Place and Duration of Study: At the experimental field of the Department of Biological Sciences, Covenant University, Ota, Ogun state, Nigeria, during the dry planting season (September – December, 2012). Methodology: A total of 26 traits comprising 18 quantitative and 8 qualitative traits of the vegetative, floral, pod and seed were evaluated using descriptive statistics, Pearson Correlation Coefficient (PCC), Principal Component Analysis (PCA) and Cluster Analysis (CA). Mitotic chromosome counts and meiotic behaviour were studied using root tip cells and pollen mother cells from young flower buds. Results: The analysis of variance showed that all quantitative morphological characters were significantly different among the accessions (P = 0.01) except stipule length and width. There were significant correlations among characters such as calyx lobe length, standard petal length and width, peduncle length, days to 50% flowering, days to 50% pod maturity, pod length and width, number of locules per pod, number of seeds per pod, and 100-seed weight which could be used for breeding and conservation purposes. The first six principal components accounted for 89.84% of the total variance. The cluster analysis segregated the 26 accessions into three main clusters; cluster I (15 accessions), cluster II (10 accessions) and cluster III (1 accession). Mitotic chromosome counts of 2n = 22 were recorded for all the accessions and meiosis was observed to be normal with the formation of eleven bivalents (n = 11). Conclusion: The intraspecific variabilities indicates plasticity in the genomes of the studied accessions, with high correlations among the morphological characters which are common to all accessions, thus justifying their grouping as a species. The morphological and reproductive attributes displayed by accessions TVnu93 and TVnu97 in terms of plant vigour, early flowering and pod maturity, longer pods and relatively high 100-seed weight made them good potential candidates in breeding for host plant resistance in cowpea

Sustainability and Genetic Diversity of Underexploited African Plants: A Collection Expedition in Nigeria - Facts, Challenges and Prospects

Plant genetic diversity loss particularly of under-utilized species threatens several developmental goals in Africa. Preferred safeguard strategies and techniques have failed in stemming this situation exacerbated by dearth in global information and poor research attention on such species amongst other pitfalls. The study involved an expedition to; generate ecogeographical and related information on 30 under-utilized species; evaluate the prevailing situations for collection exercises in Nigeria, in the attempt to instigate globally relevant researches, conservation and sustainable partnerships. A two-phased systematic field survey (North and South) employing a 50 km regular transect distance, covering the wet and dry seasons, a cumulative distance of 8168 km, 192 communities in 34 states and the Federal Capital Territory (FCT) of Nigeria. Collection diversity was determined with Simpson’s Diversity index (1-D) as well as species abundance. 703 accessions of 30 plants species were collected. 13% of the total species (16% -South; 40% - North) were common to both regions. High diversity (D = 8) was recorded for the collection. The wetter southern states were significantly more diverse (D = 0.7- 0.9) than the north. The north west and some south eastern state recorded lesser diversity and the FCT the least (D = 0). 6 species recorded significant species abundance across the study area. The study area is heavily imparted yet houses a considerable diversity of the species surveyed. It is imperative to pursue integrated strategies to harness the plentiful flora as well as cultural resources resident therein. The species studied can be employed to tackle the challenges of climate change, livelihood, economy, food and nutrition security and farmer/grazers/construction activity unrest

Genetic variability and development of cassava based products using morphometric and RAPD markers

Background and Objective: Cassava (Manihot esculenta Crantz) and its product development are important to the diversification of the crop to enhance income, food sufficiency and security. Genetic variability among 12 cassava (Manihot esculenta Crantz) varieties were assessed using morphometric and RAPD markers aimed toward product development from the varieties. Materials and Methods: Twelve morphometric characters and five random primers were employed in the genetic assessment analyses using descriptive statistics, Correlation Coefficient (CC) and Cluster Analysis (CA). Results: All morphometric characters were significantly different (p>0.01) for the varieties. Harvest index (Hi) ranged from 0.41‐0.46. The five random primers with an average of 55.2% polymorphism generated 139 polymorphic bands with primer P7 generating 68.05% of the cumulative variability observed. The RAPD analysis complemented the morphometric evaluation. The cluster analysis segregated the varieties into two major cluster groups with similar outcomes. Conclusion: The study provides improved understanding of the genetic basis of the varieties which can be exploited toward product development for commercial purpose and to ensure food security

Resolutions of C^n/Z_n Orbifolds, their U(1) Bundles, and Applications to String Model Building

We describe blowups of C^n/Z_n orbifolds as complex line bundles over CP^{n-1}. We construct some gauge bundles on these resolutions. Apart from the standard embedding, we describe U(1) bundles and an SU(n-1) bundle. Both blowups and their gauge bundles are given explicitly. We investigate ten dimensional SO(32) super Yang-Mills theory coupled to supergravity on these backgrounds. The integrated Bianchi identity implies that there are only a finite number of U(1) bundle models. We describe how the orbifold gauge shift vector can be read off from the gauge background. In this way we can assert that in the blow down limit these models correspond to heterotic C^2/Z_2 and C^3/Z_3 orbifold models. (Only the Z_3 model with unbroken gauge group SO(32) cannot be reconstructed in blowup without torsion.) This is confirmed by computing the charged chiral spectra on the resolutions. The construction of these blowup models implies that the mismatch between type-I and heterotic models on T^6/Z_3 does not signal a complication of S-duality, but rather a problem of type-I model building itself: The standard type-I orbifold model building only allows for a single model on this orbifold, while the blowup models give five different models in blow down.Comment: 1+27 pages LaTeX, 2 figures, some typos correcte

Five-Branes in Heterotic Brane-World Theories

The effective action for five-dimensional heterotic M-theory in the presence of five-branes is systematically derived from Horava-Witten theory coupled to an M5-brane world-volume theory. This leads to a five-dimensional N=1 gauged supergravity theory on S^1/Z_2 coupled to four-dimensional N=1 theories residing on the two orbifold fixed planes and an additional bulk three-brane. We analyse the properties of this action, particularly the four-dimensional effective theory associated with the domain-wall vacuum state. The moduli Kahler potential and the gauge-kinetic functions are determined along with the explicit relations between four-dimensional superfields and five-dimensional component fields.Comment: 19 pages, Latex, typos corrected, reference adde

Non-standard embedding and five-branes in heterotic M-Theory

We construct vacua of M-theory on S^1/Z_2 associated with Calabi-Yau three-folds. These vacua are appropriate for compactification to N=1 supersymmetry theories in both four and five dimensions. We allow for general E_8 x E_8 gauge bundles and for the presence of five-branes. The five-branes span the four-dimensional uncompactified space and are wrapped on holomorphic curves in the Calabi-Yau space. Properties of these vacua, as well as of the resulting low-energy theories, are discussed. We find that the low-energy gauge group is enlarged by gauge fields that originate on the five-brane world-volumes. In addition, the five-branes increase the types of new E_8 x E_8 breaking patterns allowed by the non-standard embedding. Characteristic features of the low-energy theory, such as the threshold corrections to the gauge kinetic functions, are significantly modified due to the presence of the five-branes, as compared to the case of standard or non-standard embeddings without five-branes.Comment: 34 pages, Latex 2e with amsmath, typos removed, factors corrected, refs improve

Evaluation of Efflux-Mediated Resistance and Biofilm Formation in Virulent Pseudomonas aeruginosa Associated with Healthcare Infections

Pseudomonas aeruginosa is a significant pathogen identified with healthcare-associated infections. The present study evaluates the role of biofilm and efflux pump activities in influencing high-level resistance in virulent P. aeruginosa strains in clinical infection. Phenotypic resistance in biotyped Pseudomonas aeruginosa (n = 147) from diagnosed disease conditions was classified based on multiple antibiotic resistance (MAR) indices and analysed with logistic regression for risk factors. Efflux pump activity, biofilm formation, and virulence factors were analysed for optimal association in Pseudomonas infection using receiver operation characteristics (ROC). Agespecificity (OR [CI] = 0.986 [0.946–1.027]), gender (OR [CI] = 1.44 [0.211–9.827]) and infection sources (OR [CI] = 0.860 [0.438–1.688]) were risk variables for multidrug resistance (MDR)-P. aeruginosa infection (p < 0.05). Biofilm formers caused 48.2% and 18.5% otorrhea and wound infections (95% CI = 0.820–1.032; p = 0.001) respectively and more than 30% multidrug resistance (MDR) strains demonstrated high-level efflux pump activity (95% CI = 0.762–1.016; p = 0.001), protease (95% CI = 0.112–0.480; p = 0.003), lipase (95% CI = 0.143–0.523; p = 0.001), and hemolysin (95% CI = 1.109–1.780; p = 0.001). Resistance relatedness of more than 80% and 60% to cell wall biosynthesis inhibitors (ceftazidime, ceffproxil, augumentin, ampicillin) and, DNA translational and transcriptional inhibitors (gentamicin, ciprofloxacin, ofloxacin, nitrofurantoin) were observed (p < 0.05). Strong efflux correlation (r = 0.85, p = 0.034) with MDR strains, with high predictive performances in efflux pump activity (ROC-AUC 0.78), biofilm formation (ROC-AUC 0.520), and virulence hierarchical-clustering. Combine activities of the expressed efflux pump and biofilm formation in MDR-P. aeruginosa pose risk to clinical management and infection control

Utilization of nanochitosan in the sterilization of ponds and water treatment for aquaculture

Water pollution constitutes the leading cause of infant mortality, neonatal deformities, and shrinkage of man’s average life expectancy. Pollutants come from point and nonpoint sources; and water pollution arises from the discharge of wastewater containing undesirable impurities used for domestic, agricultural, and industrial purposes. More so, high nutrient and wastewater runoffs from fish production systems contribute to the fouling and eutrophication of recipient water bodies. Hence, aquaculture which is inextricably linked to the natural environment is challenged by the dearth of appropriate water quantity and quality, militating against fish, and fishery production. Nanochitosans as polysaccharides produced by the alkalescent deacetylation of chitin, comprise a series of 2-deoxy-2 (acetylamino) glucose linked by ß-(1-4) glycosidic linkages. They are naturally formed from the deacetylation of shellfish shells and exoskeletons of aquatic arthropods and crustaceans. The unique attributes of chitin confer a wide range of biotechnological applications on the polymer, observed in flocculation as a wastewater treatment and purification route initiated by chitosan. This chapter highlights nanochitosan properties of aquaculture relevance; and elucidates the purification potentials of nanochitosan, compared to inorganic coagulants and organic polymeric flocculants. Effects of chitosan on contaminants and microorganisms, as well as applications in fish pathogens detection, fish disease diagnosis, and control are discussed