Department of Biochemistry, Cell and Molecular Biology
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Item In Vitro Studies on the Effect of Chloroquine Phosphate on the Metabolism of the Rat Red Blood Cells(University of Ghana, 1972-11) Yeboah, P.O.; Asante, G.S.; Larway, P.F.; Lovelace, C.A.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular BiologyEvidence is presented to show that in vitro. (1) High levels of chloroquine phosphate can induce hemolysis in the rat red blood cells; and (2) chloroquine-induced hemolysis is characterised by a fall in GSH levels, unless glucose is present in very high concentrations* Chloroquine phosphate is a member of the 4-aminoquinoline series of drugs used for treating acute malaria due to infection fctj Plasmodium vivdx« Plasmodium falciparum. Plasmodium malariae and Plasmodium ovale. In vitro studies were made on red blood cells incubated with chloroquine phosphate to investigate a possible chloroquine-induced hemolysis in rat red blood cells. A wide range of chloroquine phosphate concentrations were tested. After 4 hours incubation of the mixture at 3?°C; 6,3 1 10~% caused only - 2. hemolysis in the rat red blood cells; whereas 2.5 x 10 !-i chloroquine caused 66,5a hemolysis. Complete hemolysis was however observed when 4.2 x 10 chloroquine phosphate was used in the incubation system. -1 -2 Either 3.78 x 10 M glucose or 2,0 x 10 M ATP protected the red _2 blood cells from hemolysis induced by 2.5 x 10 M chloroquine phosphate. Hemolysis induced by chloroquine phosphate was found to be characterised by (a) a fall in GSH level, and (b) an increase in the osmotic fragility of the rat red blood cells. These characteristics are similar to primaquine- induced hemolysis in -.red blood cells. The possibility is discussed that based upon osmotic fragility studies, the site of hemolytic action of chloroquine phosphate could be directly on the red cell membrane where the drug might interfere with sulfhydryl groups.Item The Partial Purification of Human Erythrocyte Adenylate Kinase and the Effect of Some Common Antimalarial Drugs on this Enzyme(University of Ghana, 1976-06) Antwi, K.Y.D.; Asante, G.S; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular BiologyThe enzyme adenylate kinase (AK) was partially purified from human erythrocytes. The purification process involved the separation of the erythrocytes from whole human blood, rinsing of the cells in saline solution and finally lysing them in two volumes of water containing dithiothreitol. The crude haemolysate was dialysed against O.OlM sodium citrate buffer pH 5.0 and then treated with a suspension of CM-sephadex C-50, previously equilibrated in O.OlM sodium citrate buffer pH 5.0 containing 0.25M sodium chloride to reduce amount of haemoglobin present to effect better separation on column. After centrifuging at 30,000g the supernatant solution from this treatment was further subjected to sephadex G-100 column chromatography to obtain a partially purified enzyme preparation. The activity of adenylate kinase was measured using the coupled assay system by Oliver (1957), which is AK 2ADP ------- >AMP + ATP + hexokinase + Glucose + Mg2+ Glucose-6-phosphate + G6PD + NADP+ 6-phospho-gluconate + NADPH + H+ Absorbance at 340nm was measured for the NADPH produced over a period of 6 minutes using an SP 500 spectrophotometer with a recorder attached to it. This corresponded to ATP produced over the same period. It was found that AK was unstable at 70°C and optimum activity was observed around 37°- 40°C. Dilute solutions of AK were found to be unstable, but the enzyme was stable at 4°C in a concentrated form. Adenylate kinase activity was also found to be inhibited at high substrate (ADP) concentration, and it is known that AMP, one of the products of the reaction inhibits AK activity, competitively. From substrate concentration of 3-10mM ADP, the activity decreased. Optimum activity was obtained at substrate concentration of l-2mM ADP. The effect of some common antimalarial drugs on the enzyme activity was also looked at. The antimalarial drugs used included chloroquine diphosphate, chloroquine sulphate, quinine hydrochloride, quinine sulphate, proguanil hydrochloride, primaquine phosphate and mepacrine hydrochloride. All the drugs at a concentration of 10“^M inhibited the enzyme activity to various extent. The degree of inhibition depended on the incubation period of the enzyme with the particular drug. Quinine was found to inhibit the enzyme activity most. Inhibition of up to 62.0% was observed with quinine after 3 hours incubation period. For the same incubation period, primaquine phosphate inhibited the enzyme activity up to 42.0%, mepacrine up to 40.7%, chloroquine up to 30,3% and proguanil hydrochloride up to 28.0%. The type of inhibition, observed for chloroquine diphosphate, the most common antimalarial drug in the tropics, was noncompetitive inhibition.Item Aflatoxin Contamination of Cassava Flour (Kokonte) Processed By Traditional Methods in Ghana(University of Ghana, 1978-12) Lokko, P.G.; Gyang, F.N.; Kordylas, M.J.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular BiologyAflatoxin contamination of cassava flour (kokonte) bought in the markets of Accra has been investigated. A survey of the methods of production and of processing of the cassava chips was conducted to determine the sources of contamination in the production of the flour. Samples of the flour were analysed for aflatoxin contamination and concentrations using Thin Layer Chromatography (T.L .C.). Known levels of aflatoxin in kokonte flour samples were fed to weanling rats to determine the effects on the rats. Serum alkaline phosphatase levels were determined in the serum samples of the individual rats. The study revealed that:- (1) Three types of kokonte flour are sold at the markets of Accra and these are named according to their colours. There are red, black and white kokonte types. (2) Methods used in the processing of the cassava chips exposed the fresh roots to mould growth and hence to aflatoxin contamination. (3) Twenty-two percent of the kokonte flour samples bought from the market were found to contain aflatoxin. The mean aflatoxin concentration was calculated to be 867pg/kg. (4) There were reduced rates of growth in the rats fed on aflatoxin-contaminated diets over a period of 25 days and their food intake was also found to have reduced when compared with those of the control group. (5) The rats on aflatoxin-contaminated diets had fatty livers and there was an evidence of a growth on one of the livers. (6) Serum alkaline phosphatase levels in rats fed aflatoxin-contaminated diets were found to be higher than those observed for the rats on control diets.Item Application of Competitive Binding Assay Methods to Serum Vitamin D Levels in Health And Disease(University of Ghana, 1979) Ahene, I.S.; Chaplin,M.F.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular Biology.Competitive Binding Assay methods have been used to determine the serum levels of 25- hydroxyvitamin D^ in healthy Ghanaians and patients suffering from cirrhosis of the liver and chronic renal failure. Although the assay followed fairly standard methods as used by several workers, an improvement in stability and sensitivity was obtained by the use of gelatin in the buffer; the final assay buffer being 0.02M phosphate buffer, pH 7 ,C with 0.1% gelatin. Though rachitic rat serum was used for the main part of the work, it was confirmed that normal rat serum contained the binding protein at a suitable titre for the assay as has been reported in the literature. The normal circulating levels in 47 healthy Ghanaians was 129.0 + 55.7 ng/ml sermn, 46.0 + 16.1 ng/ml*?-.t^) for 11 patients with cirrhosis of the liver and 83.5 + 82.7 ng/ml for 8 patients suffering from chronic renal failure. Both patients'lavels were significantly different from the normal mean value ( P < 0 . 0 5 ) .Item Effect of Qhloroquine on the Induction of Rat Uterine Peroxidase by an Oral Contraceptive(University of Ghana, 1979-12) Asamoah, K.A.; Asante, S.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular Biology.Uterine peroxidase has been induced in immature female rate with estradiol and anovlar 21. Anovlar 21 is a steroid contraceptive containing 4 mg. norethisterone acetate (a progestin), and 0.O5 mg. ethinyl estradiol (an estrogen) per tablet. Maximum enzyme activity was found to occur 24 hours after oral administration of the contraceptive. The increased peroxidase activity caused by the cotrbined steroids was inhibited by the administration of cyclohexirrrLde and puromycin (inhibitors of protein biosgitheais). Peroxidase is thus synthesised de novo on the influence of the steroids. Chloroquine diphosphate has also been found to increase the activity of peroxidase, with the maximum activity occuring 18 hours after the drug has been injected intramuscularly. Cycloheximide has been found to prevent this stimulatory effect of chloroquine. Chloroquine was effective in increasing peroxidase activity in vivo over a dose range of 0-20 mg/kg. body weight. It however, did not affect peroxidase activity in vitro. Chloroquine potentiated uterine peroxidase induction by anovlar 21. Chloroquine and/or anovlar 21 prevented the production of litter by adult female rats.Item Effects Of Extracts Of The Anti-Asthmatic Plant Thonningia Sanguinea On Anaphylaxis In The Guinea Pig(University of Ghana, 1980) Nyarko, A.K.; Addy, M.E.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular BiologyThonningia sanguinea is one of the herbal preparations vised prophylactieally against asthma at the Centre for Scientific Research into Plant Medicine. Preparations of this plant are used with Desmodium adseendens which has been shown to be anti-anaphylactic. The anaphylactic reaction is a basic underlying phenomenon in asthma. In this work, the effects of T. eanguinea preparations were evaluated on some aspects of the disease. The method adopted was experimental anaphylaxis in the guinea pig. Both _in vivo and in vitro assay systems were used to evaluate extracts prepared from the plant material. The results showed that the plant material when administered orally (i) inhibited anaphylactic contractions in ileal pieces ( p < 0.05)* (ii) acted to reduce the sensitivity of ileal pieces to histamine (p < 0.05), (iii) inhibited the anaphylactic release of histamine from lung tissues (p < 0.05), (iv) reduced the amount (or effect) of mepyramine-resistant spasmogens released anaphylactically from lung tissues (p<0.05), and (v) reduced the total histamine content of lung tissues (p<0.05). The crude extract, and some of its fractions, when assayed in vitro, inhibited the anaphylactic contractions in the ileal pieces in much the same way as when the aqueous extract was administered orally (p<0.05). However, tfae ' iLn vitro effects on histaraine-induced contractions differed from the effect observed when the crude extract was administered orally. Since Thonningia preparations are administered orally, the in vitro assay system involving histamine-induced contractions, was considered to be of little or no use in evaluating the anti-asthmatic effect of the plant. These results are discussed with respect to the possible ways by which the plant could interfere with anaphylaxis and thereby prevent the incidence of asthmatic attacks. The results suggested a similar mechanism of action for both Thonningia and Desmodium. Qualitative analysis indicated the presence of enolic and/or phenolic steroids. The densitometer scan as well as Rf values and colours of resolved components could be used to control and standardize the quality of Thonningia preparations for future use.Item Proteolytic Activity In Adult Haemonchus Contortos(University of Ghana, 1982) Sackey, S. T; Oduro, K.K.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular BiologyProteolytic activity of the JQ.qOOxgsupernate of homegenates ef adult Haemonchus contortus has been studied with respect to substrates susceptible to its proteolytic activity, and the effects of factors such as temperature, pH, substrate concentration, extract concentration, dibasic metal ions, detergents, heat and some specific inhibitors of proteolytic activity. The supernate had two pH optima, 5.6 with haemoglobii as substrate, and 7.8 using L-alanyl - p-nitroanilide. It showed optimum activity at 36°C, was heat labile and in general was not significantly affected by the presence of metal ions in the hydrolysis of haemoglobin and L-alanyl p-nitroanilide. In screening for substrates susceptible to its hydrolytic action the most suitable were found to be those p-nitroanilides and jp-naphthylamides which have a single amino acid group (small R-group), unprotected at the free functional group end. The kinetic studies indicated that haemoglobin was more rfeadily hydrolysed than the p-nitroanilides and p-naphthylamides.Item Monomorphic and Pleomorphic Trypanosoma Brucei Rhodesiense: Biochemical, Morphological and Ultrastructural Comparisons(University of Ghana, 1983) Aboagye-Kwarteng, T.; Oduro, K.K.; Ormerod, W.B.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular BiologyMonomorphic and Pleomorphic Trypanosoma Brucei Rhodesiense: Biochemical, Morphological and Ultrastructural Comparisons The long slender and short stumpy forms of pleomorphic T . b. rhodesiense (LSHTM 180) have been compared to each other and to the monomorphic T. b. rhodesiense Liverpool Normal (Liv). 1. The agar film technique showed that morphologically the stumpy LSHTM 180 can be differentiated from the slender LSHTM 180 and the monomorphic T. b. rhodesiense (Liv) because it contains lipid granules. 2. Starch gel and cellulose acetate electrophoresis did not show any major differences in the isoenzyme profiles of 8 out of 9 enzymes studied. However, the presence of an aconitase band in the stumpy LSHTM 180 further differentiated it from the slender LSHTM 180 and the monomorphic T. b. rhodesiense (Liv). 3. Polypeptide profiles showed the presence of a 58,000 dalton polypeptide in extracts of both the slender and monomorphic trypomastigotes which was absent in the stumpy form. 4. Like starch gel and cellulose acetate electrophoresis, enzyme assays gave little information as to differences between the 3 trypomastigotes . There was, however, a higher NADP-isocitrate dehydrogenase activity in the stumpy form than the other two. 5. Ultrastructural studies showed the stumpy form had more cristae in the mitochondrion than either the slender LSHTM 180 or the monomorphic T. b. rhodesiense (Liv). 6. Trypomastigotes of the pleomorphic strain LSHTM 180 infected the ependymal cells of the choroid plexus, but the monomorphic T. b. rhodesiense (Liv) was unable to do this.Item Development of Precooked Foods Process and Product Evaluation(University of Ghana, 1983-06) Masopeh, E.A pre-cooked food has developed from cornmeal and cowpead flour . The cowpea seeds were germinated and also dehulled. Control seeds of these treatments were made. Method used in the preparation of the product was steaming and traditional roasting in the earthen- ware mashing boul. Chemical analysis on the products Showed that the product developed had a higher protein content than cornmeal . Evaluation of the functional characteristics revealed that the water absorbed by the products increased with an increase in the number of germination days . The undehulled products also absorbed water and swelled more than the dehulled products. This ws attributed to the presence of the seed coat in the undehulled sead products. There was not much difference in the water absorption and swelling properties with respect to the levels of corn and cowpea. Viscoamylograph runs showed no change in the gelatinisation of the germinated seed products , however there was a little increase in the viscosity of the ungerminated seed product during the holding and cooling sections. Sensory evaluation of the corn-cowpea product showed that the product was acceptable. Anaalysis of variance calculations showed a significant (p~ 0.01) effect of dehulling and cersination on the colour, odor, flavor and tho beneral acceptability of the nroducts The panelists could detect differences in the different products subjected to the different treatments. A second product similar to the corn-cowpea product was developed from corndough. Fermented and unfermented corndough were used. Functional characteristics analysis showed a high water absorption and swelling of unfermented corndough products. Analysis on the product Showed no significant difference in the colour, odor etc . of the fermented and unfermented corndough products . However, the unfermented corndough product was more acceptable.Item Development and Quality Evaluation of Pre-Gelatinized Instant Weaning Foods Based on Cereals and Legumes(University of Ghana, 1991-07) Abotsi, S.K.Item Partial Purification and Characterization of Acetylcholinesterase from Adult Onchocerca Volvulus(University of Ghana, 1992-09) Brobey, R. K. BAcetyl cholinesterase (AChE) from adult Onchocerca volvulus was extracted in either 5OmM Tris-HCl, containing Triton X-100 (detergent buffer) or plain 50mM Tris-HCl (low-salt buffer) Gel chromatography on Sephacryl S-300 column, of both the detergent buffer and the low-salt buffer extracts gave two components each./ The two components of the detergent buffer gave purification factors of 12 and 13 folds and yields of 22 and 23% respectively; those of the low-salt buffer had purification factors of 5 and 9 folds and yields of 11 and 19% respectively The two components of the detergent buffer extract had sedimentation coefficient values of 9.5S and 18S while those of the low-salt buffer extract were 11.3S, the major component in terms of activity, and >38S, the minor component. The enzyme showed a marked preference for acetylthi ocholine compared to butyry 11hioc-ho 1 ine and it was also inhibited by high concentration of the former substrate. Moreover, the enzyme was inhibited by the general cholinesterases inhibitor, serine Michae1is-menten constant (Km) of 0 .22mM and 0.28mM and '/max values of 2.7 x 10”3 and 2.5 x 10-3 nmole thiocholine min-1, were found for the respective components of the detergent buffer extract. The major component of the low-salt buffer- extract gave a Km value of 0 34mM and Vmax value of 1 9 x 10~3 umole thiocholine min"1 The two components of the detergent buffer extract had a molecular weight of 525 KD and 375 KD on Sephacryl S-300; >600 KD and 400 KD were the values obtained for the low-salt buffer extract. In contrast, polyacrylamide gel electrophoresis (PAGE) under non-denaturing conditions revealed molecular weight species of 560 KD, 355 K D , 290 KD and 67 KD for the enzymes in the detergent buffer extract; those of the low-salt buffer extract were 500 KD, 280 KD, 220 KD and 58 K D . The crude enzyme was activated by Mg+ +, Mn-+ and Ca++ at concentrations ranging from 10~4M to 10~2M. Mg++ at similar concentrations also activated the purified enzymes. Co++ moderately inhibited the crude enzyme at 10-2M. The enzyme showed maximal activity at pH 8.0 in three buffer systems. Veronal and phosphate buffers were activating. The results indicate that adult O. volvulus AChE is similar to the mammalian AChE and AChE of other nematodes in its catalytic properties.Item Phage - Mediated Transfer of Genetic Material(University of Ghana, 1993) Owusu-Biney, A.; Rodrigues K. F.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular BiologyTen phages were isolated randomly from sewage sources and disposal points on the University of Ghana,Legon campus, purified and characterised as delivery systems for the resistance marker genes, Strr and Benr. The phages were found to have proteins of relative molecular weights ranging from 9,000 - 100,000. Eight phages were found to be morphologically related to the tailed phages. The other two were tailless phages. All the coliphages isolated were morphologically related to the T-even phages, whilst Sf RBCL 15 and Sd RBCL 5 were related to the P-phages. The tailless phages were found to be morphologically related to the p phages (06 and 0X174 phages). The coliphages were found to be closely related to each other. They did exhibit some detectable cross reactivity to Sd RBCL 5, Sd RBCL 2 3 and Sf RBCL 15. The coliphages were not related to the S. tvphi phages. Selected pathogenic bacteria from the Noguchi Memorial Institute for Medical Research and the Medical School of the university of Ghana were screened for the presence of the antibiotic resistance gene marker. All the bacteria, except three, were found to be highly resistant to the marker antibiotics used : Salmonella Group D was relatively more sensitive to all three antibiotics ; Staphylococcus aureus was sensitive to Benzylpenicillin and Salmonella typhi was sensitive to Tetracycline. The isolated phages with the exception of St RBCL 2 0 exhibited the ability to transduce the resistance marker genes from one bacterium to sensitive bacteria at a high frequency.Item Phage - Mediated Transfer of Genetic Material(University of Ghana, 1993-02) Owusu-Biney, A.; Rodrigues, F.K.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular Biology; vi,130pTen phages were isolated randomly from sewage sources and disposal points on the University of Ghana, Legon campus, purified and characterised as delivery systems for the resistance marker genes, Strr and Benr. The phages were found to have proteins of relative molecular weights ranging from 9,000 - 100,000. Eight phages were found to be morphologically related to the tailed phages. The other two were tailless phages. All the coliphages isolated were morphologically related to the T-even phages, whilst Sf RBCL 15 and Sd RBCL 5 were related to the P-phages. The tailless phages were found to be morphologically related to the p phages (06 and 0X174 phages). The coliphages were found to be closely related to each other. They did exhibit some detectable cross reactivity to Sd RBCL 5, Sd RBCL 2 3 and Sf RBCL 15. The coliphages were not related to the S. tvphi phages. Selected pathogenic bacteria from the Noguchi Memorial Institute for Medical Research and the Medical School of the University of Ghana were screened for the presence of the antibiotic resistance gene marker. All the bacteria, except three, were found to be highly resistant to the marker antibiotics used: Salmonella Group D was relatively more sensitive to all three antibiotics; Staphylococcus aureus was sensitive to Benzylpenicillin and Salmonella typhi was sensitive to Tetracycline. The isolated phages with the exception of St RBCL 2 0 exhibited the ability to transduce the resistance marker genes from one bacterium to sensitive bacteria at a high frequency.Item Fi.Avoh01ds of Rpipei.Ta Frrrii01 Hi'a • Ahti-Diabetic Pr0pert1 1(3 and Tilv. Reduction 01? Li Vj5i>. Hicr030hal ['I’otjij Fl.'.(University of Ghana, 1993-09) Mills-Robertsoh, F.C.; Addy, M.E.; University of Ghana, College of Basic and Applied Sciences School of Biological Sciences Department of Biochemistry, Cell and Molecular BiologyThe an t. i - d i a b&t i c pr oper t ies of f .1 9 von oide: -x 11 a : te :i f roid B.r.idj!_l.i.a f.&rj:_a£Li. a p 1 sn t uged 3 1 Ihe 0 en f: r e For Sc 1 ,-n t i f ie Re s e a r c h I n t o F1 an t Medicine (C S RP M ) t o t r e a. t cl i ab e t e s , were vvaluated using streptozotocin -induced d iabet io :ni0e 10 represent insulin dependent diabetes mellitus (I DDK; arid genetically diabetic mice to represent non- ins;.! I in dependent i i ab e t es ;ri e 11 i t u s (NTDDM ) A 1 s o an a I y z ed wa s the ef f e r_-1 c f r extra c 1: 0 n t h e re d u c t ion of 1 i v e r m i c r 0 s 0 in a 1 p r 0 t ? :l r 1 f. . . The possible side■-effeets of the f 1 avon0 id ex1 1 ac-1 01i 1 i ve r and . Jn ey fun c t i on 5 were also ex am in ed . T he t e- s t an i n; n Is were .riven intraperitonea 1 injection of the flavonoid extract dissolved in 0.35% sa 1 in e ,=• o 1 u t i on w l'i i 1 s t t he on t r u 1 s were • i veri 0.85% saline solution w i t h ou t 11"; e 0x t r ac t . 'j' h e r rju Its 3 h 0 w e d t h a t t h e f 13 v 0 n 0 i d e 11 a c t w a s n 01 i; y p o ,e. 3 y c 3 e m i o a s i t 3.;i no ef f eo t on t he p 1 asraa glucose levels nf n jn • d j abe tic ■nice . A11 h 0 u g h the ext r a c t d i d n o t p r e v en t t h e d e v e ! o p in en t o f y erglyc s em i a in t he TDDM r.iod e 1 af t er t. he ST1 in j e t i on . i t ' *J r educe the non • f ast ing p 1 asma gIu00se levels si.eni - i an 11 y . w h erea s s u >:h e f f e c t o n f a s 1: i r j g 10 v ■; 1 w a s a I s n t 01 • ''101 signif ioant. In the cnee of the HIDDH m■: *.• 1 tii^ x '• v3.01 ■j e c r e as e d signifies r-1L y t h e n c ■ > s - f a s l.. j r 1 c. y \ .a, :i-; ! 1 <. ^ - f >.•1 . about but thf;i e u n j.c < i,|ie . ting p J a s rii a g 1 u c o s e . T h e 7- e s u .11 s t I <•> z:; o iv e ■! < b , 1 • i j ' h e s s t a ri i 111 a 1 s :i 1 j b c I: h ]. DDM u i: d f 11D D f 1 m fit L::: , 1,;--j. , w ≪., ^ /\ [) p f; y ■'.o0 hr Gine V 3 !>Ci r ed n L a e ar• K i v i I, y an !..!,■;■:?■ i.: •. ! s , ■. 11 hong h b <:• I: h t e s t ? n - J 0 - j n t r 0 I r- 11 - •' j ■■■ s 11 - -• r 0 !- \ * i \ v e r I avono ids , wh ioh are not hypog1 y c ae m ic , redu c-e pos t pr a n d i a 1 P asEta glucose levels in d iabet ic pa ti en ts . There is also an indication that t h e y red u c e the ac t i v i t y o f d r ug met ab o J. i s in g •res, probably the ones involving the cytochrome F450DM . j.jiryme. t?u toxic side-effects on the liver and kidney were !' rved.Item Fi.Avoh01ds of Rpipei.Ta Frrrii01 Hi'a • Ahti-Diabetic Pr0pert1 1(3 and Tilv. Reduction 01? Li Vj5i>. Hicr030hal ['I’otjij Fl.'.(University of Ghana, 1993-09) Mills-Robertsoh, F.C.; Addy, M.E.; University of Ghana, College of Basic and Applied Sciences School of Biological Sciences Department of Biochemistry, Cell and Molecular BiologyThe an t. i - d i a b&t i c pr oper t ies of f .1 9 von oide: -x 11 a : te :i f roid B.r.idj!_l.i.a f.&rj:_a£Li. a p 1 sn t uged 3 1 Ihe 0 en f: r e For Sc 1 ,-n t i f ie Re s e a r c h I n t o F1 an t Medicine (C S RP M ) t o t r e a. t cl i ab e t e s , were vvaluated using streptozotocin -induced d iabet io :ni0e 10 represent insulin dependent diabetes mellitus (I DDK; arid genetically diabetic mice to represent non- ins;.! I in dependent i i ab e t es ;ri e 11 i t u s (NTDDM ) A 1 s o an a I y z ed wa s the ef f e r_-1 c f r extra c 1: 0 n t h e re d u c t ion of 1 i v e r m i c r 0 s 0 in a 1 p r 0 t ? :l r 1 f. . . The possible side■-effeets of the f 1 avon0 id ex1 1 ac-1 01i 1 i ve r and . Jn ey fun c t i on 5 were also ex am in ed . T he t e- s t an i n; n Is were .riven intraperitonea 1 injection of the flavonoid extract dissolved in 0.35% sa 1 in e ,=• o 1 u t i on w l'i i 1 s t t he on t r u 1 s were • i veri 0.85% saline solution w i t h ou t 11"; e 0x t r ac t . 'j' h e r rju Its 3 h 0 w e d t h a t t h e f 13 v 0 n 0 i d e 11 a c t w a s n 01 i; y p o ,e. 3 y c 3 e m i o a s i t 3.;i no ef f eo t on t he p 1 asraa glucose levels nf n jn • d j abe tic ■nice . A11 h 0 u g h the ext r a c t d i d n o t p r e v en t t h e d e v e ! o p in en t o f y erglyc s em i a in t he TDDM r.iod e 1 af t er t. he ST1 in j e t i on . i t ' *J r educe the non • f ast ing p 1 asma gIu00se levels si.eni - i an 11 y . w h erea s s u >:h e f f e c t o n f a s 1: i r j g 10 v ■; 1 w a s a I s n t 01 • ''101 signif ioant. In the cnee of the HIDDH m■: *.• 1 tii^ x '• v3.01 ■j e c r e as e d signifies r-1L y t h e n c ■ > s - f a s l.. j r 1 c. y \ .a, :i-; ! 1 <. ^ - f >.•1 . about but thf;i e u n j.c < i,|ie . ting p J a s rii a g 1 u c o s e . T h e 7- e s u .11 s t I <•> z:; o iv e ■! < b , 1 • i j ' h e s s t a ri i 111 a 1 s :i 1 j b c I: h ]. DDM u i: d f 11D D f 1 m fit L::: , 1,;--j. , w ≪., ^ /\ [) p f; y ■'.o0 hr Gine V 3 !>Ci r ed n L a e ar• K i v i I, y an !..!,■;■:?■ i.: •. ! s , ■. 11 hong h b <:• I: h t e s t ? n - J 0 - j n t r 0 I r- 11 - •' j ■■■ s 11 - -• r 0 !- \ * i \ v e r ; o s o in a 1 p r o I:, e i n o T he re s u 11 s i n d i c a t e t !'i at, the I avono ids , wh ioh are not hypog1 y c ae m ic , redu c-e pos t pr a n d i a 1 P asEta glucose levels in d iabet ic pa ti en ts . There is also an indication that t h e y red u c e the ac t i v i t y o f d r ug met ab o J. i s in g •res, probably the ones involving the cytochrome F450DM . j.jiryme. t?u toxic side-effects on the liver and kidney were !' rved.Item Isolation and Partial Characterization of Bacteriophages(University of Ghana, 1993-09) Clement, C.; Gyang, N.F; Rodrigues, F.K; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular BiologyBacteriophages were isolated from sewage samples obtained from the Tema Sewage Disposal Plant and the Legon vicinity using the indicator bacteria strains Shigella dysenteriae. Salmonella typhi. Escherichia coli, and Salmonella typhi Group D. Ten phages were isolated and partially characterized by electron microscopy, DNA fingerprinting and protein profiles by SDS-PAGE. The relatedness of the phages was determined by immunological studies. Some of the phages were screened for their ability to transduce antibiotic resistance markers. The phages were found to be similar to T-even phages and P phages. The morphology possessed by a phage was independent of the host specificity, which is phages of different morphologies could attack one bacteria strain. The restriction fragment lengths of the phage DNA ranged between 0.125-33.113 kilobasepairs (kbp) and one fragment of fragment length 23.000kbp was common to nine phages, suggesting a relationship between phage nucleic acid and morphologies. Phage EcRCL24 for which antisera was raised was found to show an appreciable cross reactivity with the other EcRCL phages and they are therefore closely related. The phages are presumed to be capable of generalized transduction and the frequency of 3 x 10-6 for penicillin-V sulfoxide and 3 x 10-7 for tetracycline and erythromycin suggests a relatedness of the indicator bacteria strains' chromosomes. The additional information obtained within the scope of the project, involved comparison of minimum inhibitory concentration (MIC) values and those obtained by the induction of increased tolerance levels of antibiotics in the clinical isolates. It showed that, these pathogens could tolerate about double their MIC values in the increased tolerance level experiments. Furthermore their MIC values were considerably higher than the chemotherapeutic dosages.Item Sensitivity of Asexual Blood Stages Of . Plasmodium Berghet (Nk 65) to Chloroquine(University of Ghana., 1994-03) Aryee, N.A.The erythrocytic developmental cycle of Plasmodium berghei can be conveniently divided into the ring, tropho-zoite and schizont stages based on morphology. The sensitivity and effect of chloroquine on density-gradient isolated fractions of each of these stages was investigated using the plasmodial strain P.berghei (NK65), a rodent model as an experimental tool. This plasmodial strain was found to be routinely lethal in infected mice in the absence of administered therapeutic levels of chloroquine. P.berghei infected blood was separated into the various developmental stages using discontinuous Percoll gradient centrifugation. The various stage-isolated fractions were found to be infective and sensitive to these same levels of chloroquine. However chloroquine was found to show insignificant differential sensitivity with regards to the developmental stage of berghei (NK 65) strain.Item Restriction Fragment Length Polymorphism (RFLP) in Palm wine Yeast Taxonomy(University of Ghana, 1994-09) Brown, C.A; Oduro, K.K; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular BiologyReports on the number of isolates and yeast species obtained from palm wine samples have differed very widely. One factor that probably accounts for this is the method of phenotypic discontinuity which has exclusively been employed in palm wine yeast speciation. The phenotypic features used mainly for this kind of speciation have been shown to be unstable. Consequently it was decided to employ the more consistent; and reliable method of Restriction Fragment Length Polymorphism (RFLP) to ascertain the veracity or otherwise of the literature reports on palm wine yeast isolates. Out of the ten palm wine yeast samples carefully selected from different localities in Southern Ghana, nine showed only one yeast isolate while the tenth sample (from Legon village) showed two isolates. All the yeast isolates were identified as Saccharomyces cerevisiae. The genomic DNA restriction fragment patterns of all the palm wine yeast isolates were examined following the isolation and purification of their DNAs, restriction enzyme digestion of the isolated DNAs, and 0.7% agarose gel electrophoresis at 100 V for 1.3 hours. While the nine isolates PW/B/1, PW/B/2 through to PW/B/9, showed identical patterns, irrespective of any of the seven restriction endonuclease enzymes, Apa I, BamH I, EcoR I, Hind III, Kpn I, Psl I and Sma I used, the patterns of the two isolates from Legon differed slightly from the other nine, but were identical to each other. From these results, it was concluded that isolates PW/B/1, PW/B/2 through to PW/B/9, are the same species, while the other two, PW/B/lOa and PW/B/lOb are either subspecies or strains of these nine.Item Comparative Studies of Pollution Induced Microsomal Nadph-Dependent Cytochrome P-450 Monooxygenase Enzyme Complex of Tilapia Species(University of Ghana, 1994-10) Faabeluon, L. FThe baseline levels of hepatic microsomal proteins of cytochrome P-450 monooxygenase enzyme complex of two economically important tilapia species, Oreochromis! niloticus and Seratherodon. galilaeus. Were measured and compared with the levels of the enzyme in O. niloticus injected with J5-naphthoflavone (fl-NF) a classical inducer of cytochrome P-4501A isozyme, and O. niloticus exposed to effluents from Akosombo Textiles Limited (ATL-E). This was done in order to find out if this enzyme complex could be used as a biomarker to determine the ATL effluent effects on the fish species in the Volta Lake into which the effluent is discharged. The relationship between exposure to the pollutants and the health status of the fishes was assessed by measuring two biological indices - condition factor (CF) and liver I somatic index (LSI). Total protein concentration was determined by the Folin-Lowry method. The activities of NADPH cytochrome P -450 reductase, a component of the monooxygenase enzyme complex, were measured using reduction of exogenous cytochrome c. Cytochrome P-450 enzyme activity was measured using ethoxyresorufin-O-deethylase (EROD) assay which indicates specifically the induction of cytochrome P-4501A isozyme. The results indicate no relationship between the exposure to the pollutants, ATL-E and fi-NF, and the CF (one of the biological indices). On the other hand, there was a relationship between exposure to ATL-E and the health status of the fish expressed as liver somatic index (LSI). The results further indicate that the total microsomal protein concentration and the total cytochrome P-450 reductase activity of $. Galilaeus were 2-fold and 1.5-fold higher than the values in Q. niloticus. The total microsomal protein concentration of the ATL-E controls, that is fishes at Konkontekope, showed a significant increase relative to the aquarial fi-NF controls. In spite of the higher protein concentration of the ATL-E control fishes over the aquarial controls, there was no difference in their total reductase activity. Both types of control fishes as well as the S- ealilaeus did not show any response to the EROD assay indicating the absence of cytochrome P-4501A isozyme in the microsomal proteins induced. There was a significant increase in the total microsomal protein concentration of test fishes over their controls. Microsomes from fishes exposed to the ATL effluent showed increases in the total NADPH cytochrome P-450 reductase activity compared to their controls, unlike the microsomes from fishes injected with fl-NF. However, microsomes prepared from both 13-NF-injected and ATL-E exposed fishes responded to the EROD assay indicating the presence of cytochrome P-4501A isozyme induction by these pollutants. The induction of total NADPH cytochrome P-450 reductase by the factory effluent suggests that the xenoorganics in the factory effluent could belong to the PB-type or the third type of inducers. That the cytochrome P-4501A protein was induced by the factory effluent, as evidenced by the positive response to EROD assay, indicates that the effluent contains the 3-methylcholanthrene type of inducers. This study h^s indicated that the effluent from the Akosombo Textiles Limited contains a mixture of inducers - the 3-MC type, the PB-type and the third type. The three types of inducers may act synergistically to promote the induction exhibited. The molecular weight(s) of the monooxygenase isozymes induced by both BNF and ATL-E were resolved electrophoretically on 10% SDS-PAG. The BNF and ATL-E exposed fishes were found to induce protein isozymes with similar electrophoretic mobilities with an approximate molecular weight of 53,700 daltons.Item G-Protein Transduction M Iend Siaactcehda Srigonmaylc Es Cerevisiae(University of Ghana, 1995-09) Dzudzor, B.; Gyang, N.F.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular BiologyYeast mating type locus gene alpha2 (MATa2), Yeast G protein complementing gene ( YGC1) and minichromosome maintenance gene (M C M 1) have been identified by isolation of plasmids that are able to complement or suppress a gpa1::HIS3 mutation. MATa2 and YGC1 rescue both MATa and MATa-gpa1::HIS3 haploid cell types whereas MCM1 complements only MATa gpal::HIS3 cell type. MATa2 is known to be a general repressor and a determinant of both haploid and diploid cell types. MCM1 is known to be a general transcriptional activator. YGC1 has not been characterised, hence its function or mode of action is not previously known. G protein alpha subunit (GPA1) is a yeast G protein a subunit that negatively controls the budding yeast pheromone signal transduction pathway. Disruption of GPA1 results in constitutive arrest of the signal pathway that leads to cell cycle arrest at the early G1 phase of the cell cycle. Both Southern analysis and sequencing showed that MATa2, YGC1, MCM 1 have no homology to GPA1. Disruption of MATa2 (that is mata2::URA3) leads to constitutive arrest of the cell cycle at the G 1 phase. MATa2 also has no sequence homology to G P A 2 , the other G protein a subunit in yeast, known to be involved in cAMP pathway in yeast. It has been shown here that MATa2 rescues gpal::HIS3 cells even in single copy, centromere plasmids. Mating efficiency is largely reduced in cells kept alive with MATa2. MATa2 does not have the pheromone response elements (PREs) common to the STE genes (whose disruption leads to insensitivity to mating factors). The plasmid TGC was also constructed and used in creation of the yeast haploid strains LG1 and LG2. This was an attempt to screen a mammalian cDNA library for possible analogs of GPA1. These strains were used to isolate two mammalian analogs that complement the gpa1::HIS3 mutation. The results indicate that MATa2, YGC1 and MCM1 are components or modulate component(s) of the signaling pathway. It also showed that MATa2 is even a more potent negative regulator of the signaling pathway than GPA1, since overexpression is not a prerequisite for negatively regulating the pathway. MATa2 does not belong to the G protein family since it has no GTP/GDP binding and/or exchange domains.