The Distribution and Seasonal Variation of Zooplankton Species of the Great Kwa River, Calabar, Nigeria: A Reassessment Approach

Background: Human activities adversely affect the distribution and diversity of zooplankton. They are diverse group of organisms with little or no locomotive ability and quickly respond to changes in their environment. This research was aimed at providing updated information on the distribution and seasonal variation of zooplankton in Great Kwa River. Materials and Methods: Two sampling stations (S1- Obufa Esuk and S2- Esuk Atu) were mapped along the river bank, samples were collected using plankton net of 55祄 mesh size and preserved in 4% formalin. Species were identified using taxonomic keys. Data were analyzed using ecological indices. Results: The results revealed 12 taxa; belonging to 38 species. Tintinnida, Protozoa, Cladocera, Copepoda were 23.1%, 18.5%, 15.4% and 13.3% respectively. The lowest taxonomic groups were Diptera, Foraminitera, Atenatadata and Trichoptera having 1.85% for each order. The highest species was recorded in S2 having 31 species. In both Stations Ascampbelliella acuta was dominance over other species. Shannon-Weiner index (H) were 2.997 and 2.40 in S2 and S1 respectively. The evenness index were 0.576 and 0.547 for S1 and S2 respectively. Margalef,s diversity index were 8.171 and 4.111 for Esuk Atu-S2 and Obufa Esuk-S1 respectively. Zooplankton species were abundant in wet season than dry season. Conclusion: This present study provide updated information on the zooplankton distribution, diversity and seasonal variations of the Great Kwa River. The high dominance of Tintinnida in this study indicates a natural linkage between nano-planktons and macro-planktons in the food webs of the river.

Spermatotoxic Effects of Some Medicinal Plants (Carica papaya, Hibiscus rosa-sinensis and Ipomoea batatas) on Sperm Quality and Testicular Weight in Male African catfish (Clarias gariepinus)

This study was designed to evaluate the effects of pawpaw (Carica papaya) seeds, hibiscus plant (Hibiscus rosa-sinensis) leaves andsweet potato (Ipomoea batatas) leavesextractson sperm quality (sperm motility, sperm density, semen volume) and weight of testes of male Clarias gariepinus.One hundred and twenty (120) juveniles of C. gariepinuswere collected from the University of Calabar fish farm. The 120 fish were randomly divided into 12 experimental tanks measuring 80x80x80cm (L x W x H), with three tanks for each treatment, using a completely randomized design (CRD). Three grams (3g) of each test plant were incorporated into 1kg of Coppens feed (3g/kg) and reformulated into four experimental diets; Treatment A-Control, B-Pawpaw seed meal (PSM), C-Hibiscus leaf meal (HLM) and D-sweet potato leaf meal (SPLM). The experiment was done in three replications. The fish were fed twice daily for 6 months. Data obtained were analyzed using a one way analysis of variance (ANOVA). Results showed that fish fed with HLM had significantly (p =.05) higher testicular weight when compared with the control and other test plants. Moreover, sperm volume and density significantly (p =.05) reduced in fish samples treated with PSM and SPLM when compared with the control and fish fed with HLM. The highest mean sperm volume and density were obtained in fish samples fed with HLM. No significant difference was observed in the sperm motility of the fish in all the treatment groups. Conclusively, this study reveals the pro-fertility potential ofH. rosa-sinensisin maleC. gariepinuswhile C. papaya and I. batatas possess anti-fertility properties. Therefore, HLM can be utilized as feed additive to minimize the dependence on synthetic drugs as fertility enhancing agents.

Reproductive Performance of Carica papaya, Hibiscus rosa-sinensis and Ipomoea batatas on Female African Catfish (Clarias gariepinus)

This study investigated the reproductive performance of pawpaw (Carica papaya) seeds, hibiscus plant (Hibiscus rosa-sinensis) leaves and sweet potato (Ipomoea batatas) leaves on some reproductive parameters (ovary weight, mean egg diameter and egg fecundity) in female African catfish (Clarias gariepinus). One hundred and twenty (120) juveniles of C. gariepinus were collected from the University of Calabar fish farm. The 120 fish were randomly divided into 12 experimental tanks measuring 80x80x80 cm (L x W x H) using a completely randomized design (CRD). Three grams (3 g) of each test plant were incorporated into 1 kg of Coppens feed (3 g/kg) and reformulated into four experimental diets; Treatment A- Control, B- pawpaw seed meal, C- Hibiscus leaf meal and D- sweet potato leaf meal. The experiment was done in three replications. The fish were fed twice daily for 6 months. Data obtained were analyzed using a one way analysis of variance (ANOVA). Results obtained revealed that the different test substances significantly (p<0.05) negatively affected the different reproductive parameters studied. The ovary weight, gonadosomatic index (GSI), egg diameter, fecundity as well as total weight significantly (p<0.05) decreased in all the treated fish when compared with that of the control. Pawpaw seed meal (PSM) had the highest effect on the reproductive parameters of the fish studied (ovary weight, GSI, fecundity and egg diameter values of 14.89±5.51, 0.82±0.30, 19371±51.84 and 0.63±0.07, respectively) when compared to the other test plants. The findings of this study suggest that C. papaya seeds, hibiscus leaves and sweet potato leaves have the potential to impair reproductive performance in female African catfish. Therefore, holistic measures should always be taken when using these plants considering the effect it could exert on other aquatic inhabitants and systems.

Production of specific monoclonal antibodies to Burkholderia pseudomallei and their diagnostic application.

Hybridomas secreting monoclonal antibodies (MAbs) specific to Burkholderia pseudomallei were produced by immunizing BALB/cJ mice with crude culture filtrate of B. pseudomallei. Two monoclonal antibodies were found to be highly specific to B.pseudomallei as tested by indirect enzyme-linked immunosorbent assay and immunoblotting against a panel of crude whole cell extracts from B. pseudomallei, B. cepacia, Pseudomonas aeruginosa, P.putida, and Escherichia coli. One of the specific MAbs, clone SP-M, IgM subclass, could directly agglutinate all 42 B. pseudomallei, isolates. The study has shown that the agglutinating MAb has potential for rapid identification of B. pseudomallei in primary bacterial culture from clinical specimens. The antibody can be used in bacteriology laboratories to reduce time of biochemical methods, which require a few days.

Monoclonal antibodies against protein antigens of salmonellae causing paratyphoid fever and their diagnostic application.

Hybrid clones producing monoclonal antibodies (MAbs) specific for Salmonella paratyphi A (72 clones), S. paratyphi B (9 clones) and S. paratyphi C (8 clones) were produced by using the affinity purified Salmonella protein (Bp) as immunogens. MAbs to S. paratyphi A and S. paratyphi B reacted specifically with the 52 kDa homologous flagellin protein components while those to S. paratyphi C reacted with a 61 kDa flagellin protein component. The MAbs against S. paratyphi A and S. paratyphi B were used to establish a double antibody sandwich ELISA for detection of the 52 kDa flagellin antigens in serum samples from patients with acute paratyphoid A and paratyphoid B fever. With this assay system, 6.25 ng per ml of flagellin antigens of S. paratyphi A and S. paratyphi B could be detected. However, the assay system could not detect the flagellin antigens in patients' sera. The presence of IgM antibodies to the 52 kDa antigens of S. paratyphi A and S. paratyphi B in the acute sera from paratyphoid A or paratyphoid B patients suggested that the 52 kDa protein components of both salmonellae are good immunogens for human and might be used as antigens for early diagnosis of paratyphoid A and paratyphoid B fever.

Molecular cloning and expression of Salmonella paratyphi A 52 kDa specific protein gene.

Monoclonal antibodies (MAbs) specific to Salmonella paratyphi A have been established by our group in 1989. These MAbs were proven to be species-specific for 52 kDa protein of S. paratyphi A but the nature of this protein is unknown. However, our group have proved that the 52 kDa protein which is specific to S. typhi was flagellin. This present study has characterized the 52 kDa protein of S. paratyphi A and identified its encoded gene. The plasmid containing the specific 52 kDa antigen gene was cloned from the S. paratyphi A genome, herein designated pSKA-4. Partial nucleotide sequences from this clone was analysed by computer program and found to be phase 1-a flagellin gene of S. paratyphi A. In addition, the nucleotide sequence analysis from such clone also showed that the structural gene for phase 1 flagellin has amino acid sequences conserved at the terminal whereas the central region is variable among Salmonella spp. Therefore, the central portion of flagellin which highly polymorphic in amino acid sequences would be the most specific to S. paratyphi A, thus, should be used as specific antigen for developing specific diagnosis of S. paratyphi A infection. Using the PCR technique, an expression plasmid containing the antigen gene producing only the variable region in the central portion of flagellin from S. paratyphi A, namely pSKA-7, has been established. The recombinant protein produced by the established plasmid has a MW 33.5 kDa as detected by immunoblotting using specific MAbs. Further study by using this specific flagellin protein for immunodiagnosis of S. paratyphi A infection is being carried out in our laboratory.

Fusion protein of Salmonella typhi flagellin as antigen for diagnosis of typhoid fever.

We previously established the specific 52 kDa antigen of Salmonella typhi, detected by our monoclonal antibodies, which was a flagellin protein. Comparison of the nucleotide sequences of phase-1 flagellin of Salmonella species available through GenBank database showed high homology at both ends of the genes with lower degree of homology in the middle portion which contained the antigenically variable regions. Thus, proteins from the central regions of flagellin genes should be species specific and could be used as specific antigens for the immunodiagnostic tests. In this report, recombinant protein derived from the central region of S. typhi flagellin was produced as a fusion protein with glutathione-S-transferase. This fusion protein was used as specific S. typhi antigen for the immunodiagnostic test to detect IgM antibodies in sera using enzyme-linked immunosorbent assay. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of this test were 53.5, 98.0, 91.5, 82.1 and 92.4%, respectively.

Production of monoclonal antibodies to Vi polysaccharide antigen of Salmonella typhi.

Twenty-four Vi antigen-specific monoclonal antibodies were produced in this study. The MAbs were found to be highly specific to Vi possessing bacteria. Selected MAbs were used in a direct agglutination assay for rapid identification of S. typhi in primary bacterial culture and also used to develop an assay to detect Vi antigen in clinical specimens. The result showed that they could not detect the antigen in urine and serum from acute patients even they could detect as low as 0.02 micrograms/ml of Vi antigen added in normal urine. The study has shown that these MAbs are very useful for rapid identification of S. typhi in primary bacterial culture and they can replace polyclonal anti-Vi antibodies which have been used routinely in bacteriological laboratories.

Molecular cloning and expression of Salmonella typhi flagellin: characterization of 52 kDa specific antigen of S. typhi.

We previously reported monoclonal antibodies (MAbs) specific to S. typhi 52 kDa antigen which do not cross react with related protein antigens from 11 bacteria causing enteric fever and enteric fever-like illness. Using the combination of these specific MAbs and recombinant DNA technology, expression plasmids containing the antigen gene producing substantial amount of the S. typhi protein antigen have been established. Plasmid pSKM-T7 containing the specific 52 kDa antigen gene was cloned and the antigen expressed was detectable by immunoblotting using specific mAbs. The complete nucleotide sequence of this gene was compared with other bacterial sequences and found to be highly homologous with the flagellin gene H1-d of S. muenchen except in the hypervariable region in the central portion. The specific 52 kDa antigen of S. typhi detected by our MAbs is thus a flagellin.