Comparative study of some enzymes in different varieties of fruits

Arginase, rhodanese and thiaminase are enzymes often encountered and that play crucial roles in different metabolic pathways. These enzymes were found to be present in different fruits: avocado pear (Persea americana), water melon (Citrullu slanatus), green exotic apple (Malus domestica), red exotic apple (Malus pumila), red local apple (Syzygium malaccense); pink local apple (Syzygium samarangense); sweet orange (Citrus sinensis), tangerine (Citrus tangerina), lime (Citrus aurantifolia), pawpaw (Carica papaya), banana (Musa acuminata), pineapple (Ananas comosus) and grape (Citrus paradisi). It was found that avocado pear has highest activity of arginase, rhodanese and thiaminase than the rest of the fruits  investigated. The specific activity of rhodanese was however highest in water melon while that of arginase was more or less the same in red local apple and avocado pear. Arginase was also seen to vary significantly in the different plant samples with orange having the highest mean value of activity while sweet potato showed no activity. The study provides   information on the presence of thiaminase, arginase and rhodanese in the different plants for nutritional purpose.Keywords: Enzymes, arginase, rhodanese, thiaminase, fruits

Isolation and kinetic properties of arginase in the gut of grasshopper (Zonocerus variegatus Linn)

Arginase (EC 3.5.3.1) catalyzes the hydrolysis of arginine to ornithine and urea. Arginase was purified and characterized from the gut of Zonocerus variegatus through DEAE-cellulose and biogel-P100 gel filtration chromatography. The specific activity of the enzyme was 3.7 μmoles/min  per mg of protein and a yield of 14.7%. An apparent molecular weight of 143,000 daltons was estimated by gel filtration on biogel P-100. The Michaelis constant (Km) of the enzyme was 40 mM with arginine as substrate. The optimum pH was 8.0 and the optimum temperature was 40 oC for Z. variegatus arginase. The enzyme was stable up to 40 oC for 20 min and lost all of its activity at 80 oC. The enzyme was specific for arginine as substrate. The enzyme was strongly enhanced in the presence of Mn2+, Na+, NH4 + and Hg2+ showed similar activation. Ni2+ and Zn2+ slightly inhibited Z. variegatus. Chelating (EDTA, citrate, ascorbic acid and urea) and thio (2-mercaptoethanol and cystein) compounds inhibited the activity of arginase in Z. variegatus. While amino acids (proline, lysine, aspartate and valine) showed no inhibition on arginase activity. The presence of arginase in the gut of Zonocerus variegatus could be for other functions rather than urea production in urea cycle. © 2013 International Formulae Group. All rights reserved. Keywords: Arginase; Zonocerus variegatus; Distribution; Physicochemical Properties

Inhibition of glutathione S-transferases (GSTs) activity from cowpea storage bruchid, Callosobrochus maculatus Frabiricius by some plant extracts

Crude ethanolic extracts of Tithonia diversifolia, Cyperus rotundus and Hyptis suavolens have insecticidal activity against Callosobrochus maculatus Frabiricius. The ethanol extracts of the plants have positive results for alkaloids, saponin, tannins and flavonoids. Antioxidant and reducing properties were also determined in the crude ethanol extracts. Cowpea storage bruchid, C. maculatus glutathione S-transferases was a potential target for the plants extracts. Gluathione S-transferase fromcowpea storage bruchid was purified by affinity gel chromatography of glutathione sepharose. Inhibition effect of the plant extracts on the GST was studied by spectrophotometric method. The binding of the extract was competitive by the Dixon plot with Ki of 84, 132 and 180 ug/mL for T.diversifolia , C. rotundus and H. suavolens, respectively. We suggest that reported efficacy of the extract is due to the antioxidant properties and competitve binding inhibition on GST may contribute to the pharmacological basis of the efficacy against cowpea storage bruchid, C. maculatus Frabiricius and its attendant managements

The Distribution of the Enzyme Arginase in the Tissues of Selected Cichlidae Species: Tilapia zillii, Sarotherodon galilaeus and Oreochromis niloticus

The paper reports the tissue distribution of the enzyme arginase in three different Cichlids: Tilapia zilli, Sarotherodon galilaeus and Oreochromis niloticus, from the Aiba and Osinmo reservoirs, located in the southwestern Nigeria. The tissues of S. galilaeus showed very high activity of arginase as compared with the other two species. The liver of O. niloticus and the gut of T. zillii showed very high activity of arginase in the Osinmo reservoir. The high arginase activity observed in the tissues of these organisms is attributed to ureotelism and is similar to the result obtained for tilapia, Alcolapia grahami, from lake Magadi, Kenya

Rhodanese is a Possible Enzyme Marker for Cyanide Environmental Stress on Aquatic Life

Rhodanese is a cyanide detoxifying enzyme. The role of man through his anthropogenic activities in and around water bodies have increased in recent times. These have led to constant exposure of water body to cyanide and cyanide compounds with increase to loss of many aquatic lives. There are limited methods employed in quick detection of cyanide in water. The aim of this paper was to present rhodanese, an enzyme, as a possible marker for detecting and monitoring water pollution as a result of environmental stress from anthropogenic activities and constant climatic changes.Keywords: Rhodanese, Aquatic Life, Water Body, Cyanide, Toxicit

Properties of Arginase from the Hepatopancreas of Giant Freshwater Prawn (Macrobrachium rosenbergii, de Man).

We describe the hepatopancreas arginase activity of freshwater prawn (Macrobrachium rosenbergii). The enzyme was isolated using reactive blue 2- agarose affinity chromatography and gel filtration on Sephadex G-150. The enzyme had a specific activity of 5.70 μmol/min/mg of protein. The enzyme exhibited a maximal activity at pH 8.5 and Km of 12.5 mM. The enzyme was capable of hydrolysing L-arginine and to a lesser extent, L-arginine monohydrochlorate and L-arginine monohydrate. The optimum temperature of the enzyme was 35 0C. The molecular weight as determined by gel filtration was approximately 160,000 dalton and SDS-PAGE, was 22,000 dalton. The different amino acids (L-lysine, L-cysteine, Lvaline, L-proline, L-aspartic acid, L-glutamic acid and L-serine) and metal ions (Ni2+, Co2+, Zn2+, Mn2+ and Mg2+) did not show any inhibition on the enzyme activity. The enzyme was activated with Mn2+ and different concentration of Mn2+ had no effect on the enzyme activity. EDTA, citrate and urea showed considerable inhibition on the enzyme activity.Key words: Freshwater prawn; arginase; uricotelism; invertebrates; hepatopancrea

In Vitro study on α-amylase inhibitory activities of Digitaria exilis, Pentadiplandra brazzeana (Baill) and Monodora myristica.

In the present study, the hot and cold aqueous extracts of Digitaria exilis and Pentadiplandra brazzeana (Baill) as well as the ethanolic extract of Monodora myristica were screened for their anti diabetic activity via inhibition of α-amylase. The root of Pentadiplandra brazzeana Baill and the grains of Acha (Digitaria exilis) were extracted by Soaking in hot and cold water while the seed of Monodora myristica was extracted using 70% ethanol. α-amylase was significantly inhibited by Digitaria exilis, Pentadiplandra brazzeana Baill and Monodora myristica. Results showed that the three plants can act as potent α-amylase inhibitor. The cold aqueous extract of Pentadiplandra brazzeana Baill showed the highest inhibition against pancreatic α-amylase among the plants studied with IC50 value of 197.63±1.450 μg/ml while the ethanolic extract of Monodora myristica showed the least with IC50 value of 408.17±2.945. α-amylase inhibitors from herbal sources offer an attractive therapeutic approach to the treatment of postprandial hyperglycemia by decreasing glucose release from starch and may have potential for use in the treatment/management of diabetes mellitus and obesity.Keywords: α-amylase inhibition, diabetes mellitus, postprandial hyperglycemia

Prevalence, years lived with disability, and trends in anaemia burden by severity and cause, 1990-2021: findings from the Global Burden of Disease Study 2021

Background Anaemia is a major health problem worldwide. Global estimates of anaemia burden are crucial for developing appropriate interventions to meet current international targets for disease mitigation. We describe the prevalence, years lived with disability, and trends of anaemia and its underlying causes in 204 countries and territories. Methods We estimated population-level distributions of haemoglobin concentration by age and sex for each location from 1990 to 2021. We then calculated anaemia burden by severity and associated years lived with disability (YLDs). With data on prevalence of the causes of anaemia and associated cause-specific shifts in haemoglobin concentrations, we modelled the proportion of anaemia attributed to 37 underlying causes for all locations, years, and demographics in the Global Burden of Disease Study 2021. Findings In 2021, the global prevalence of anaemia across all ages was 24·3% (95% uncertainty interval [UI] 23·9–24·7), corresponding to 1·92 billion (1·89–1·95) prevalent cases, compared with a prevalence of 28·2% (27·8–28·5) and 1·50 billion (1·48–1·52) prevalent cases in 1990. Large variations were observed in anaemia burden by age, sex, and geography, with children younger than 5 years, women, and countries in sub-Saharan Africa and south Asia being particularly affected. Anaemia caused 52·0 million (35·1–75·1) YLDs in 2021, and the YLD rate due to anaemia declined with increasing Socio-demographic Index. The most common causes of anaemia YLDs in 2021 were dietary iron deficiency (cause-specific anaemia YLD rate per 100 000 population: 422·4 [95% UI 286·1–612·9]), haemoglobinopathies and haemolytic anaemias (89·0 [58·2–123·7]), and other neglected tropical diseases (36·3 [24·4–52·8]), collectively accounting for 84·7% (84·1–85·2) of anaemia YLDs. Interpretation Anaemia remains a substantial global health challenge, with persistent disparities according to age, sex, and geography. Estimates of cause-specific anaemia burden can be used to design locally relevant health interventions aimed at improving anaemia management and prevention. Funding Bill & Melinda Gates Foundation

Involvement of cholinergic-muscarinic receptor in Anaphe venata-induced stretching-ataxia behavioral effects in rats

Anaphe venata entomophagy has previously been implicated in the aetiopathogenesis of seasonal ataxia in humans and altered motor function in rodents. Thus, we investigated the effect of A. venata PhosphateBuffer Saline (PBS) extract on stretching, ataxia and the possible mechanism(s) of action. Animals were divided into four groups (n = 6-12 per group) and graded doses of extract (100, 200 or 400 mg/kg) wereadministered intraperitoneally (i.p.) while the control group received saline. Behavioral scores were recorded for a period of 30 min immediately after the administration of saline or extract. The role of various receptors inthe extract induced stretching and ataxia was evaluated using known receptor antagonists in other groups of rats. The in-vitro cholinesterase inhibition assay of the extract was also performed. The protein profile of theextract was evaluated using the Sodium Dodecyl Sulphate  (SDS)-Polyacrylamide gel electrophoresis. Results showed that the extract induced significant (p<0.01) stretching and ataxia behavioural effects dose-dependently when compared to vehicle-treated rats. Pretreatment with the non-selective muscarinic antagonist, scopolamine, significantly (p<0.05) reversed both stretching and ataxia-induced behaviour of PBS extract at alldose levels however both flumazenil and naloxone did not show any significant effects. Anticholinesterase assay also provided evidence that the extract has inhibitory effect on acetylcholinesterase enzyme. Electrophoresis assay suggested that the major proteins in the extract are probably of small molecular weight. In conclusion, the A. venata PBS extract induced-behaviours are probably mediated via the activation of cholinergic-muscarinic receptor systems

Past, present and future molecular diagnosis and characterization of human immunodeficiency virus infections

Substantive and significant advances have been made in the last two decades in the characterization of human immunodeficiency virus (HIV) infections using molecular techniques. These advances include the use of real-time measurements, isothermal amplification, the inclusion of internal quality assurance protocols, device miniaturization and the automation of specimen processing. The result has been a significant increase in the availability of results to a high level of accuracy and quality. Molecular assays are currently widely used for diagnostics, antiretroviral monitoring and drug resistance characterization in developed countries. Simple and cost-effective point-of-care versions are also being vigorously developed with the eventual goal of providing timely healthcare services to patients residing in remote areas and those in resource-constrained countries. In this review, we discuss the evolution of these molecular technologies, not only in the context of the virus, but also in the context of tests focused on human genomics and transcriptomics