Khalid M. Naji

Rosenbergiella bacteria have been previously isolated predominantly from floral nectar and identified in metagenomic screenings as associated with bees. Here, we isolated three Rosenbergiella strains from the robust Australian stingless bee Tetragonula carbonaria sharing over 99.4% sequence similarity with Rosenbergiella strains isolated from floral nectar. The three Rosenbergiella strains (D21B, D08K, D15G) from T. carbonaria exhibited near-identical 16S rDNA. The genome of strain D21B was sequenced; its draft genome contains 3,294,717 bp, with a GC content of 47.38%. Genome annotation revealed 3236 protein-coding genes. The genome of D21B differs sufficiently from the closest related strain, Rosenbergiella epipactidis 2.1A, to constitute a new species. In contrast to R. epipactidis 2.1A, strain D21B produces the volatile 2-phenylethanol. The D21B genome contains a polyketide/non-ribosomal peptide gene cluster not present in any other Rosenbergiella draft genomes. Moreover, the Ros...

Background Environmental contamination from synthetic plastics and their additives is a widespread problem. Phthalate esters are a class of refractory synthetic organic compounds which are widely used in plastics, coatings, and for several industrial applications such as packaging, pharmaceuticals, and/or paints. They are released into the environment during production, use and disposal, and some of them are potential mutagens and carcinogens. Isophthalate (1,3-benzenedicarboxylic acid) is a synthetic chemical that is globally produced at a million-ton scale for industrial applications and is considered a priority pollutant. Here we describe the biochemical characterization of an enzyme involved in anaerobic degradation of isophthalate by the syntrophically fermenting bacterium Syntrophorhabdus aromaticivorans strain UI that activate isophthalate to isophthalyl-CoA followed by its decarboxylation to benzoyl-CoA. Results Isophthalate:Coenzyme A ligase (IPCL, AMP-forming) that activat...

... Ethnopharm. Bull., 93(1), 43 – 49. Kuku, A., Odekanyin, O., Adeniran, K., Adewusi, M., Olonade, T. (2009). Purification of a mannose/glucose-specific lectin with antifungal activity from pepper seeds (Capsicum annum). Afr. J. Biochem. Res., 3(6), 272-278. ...

Leaves and buds of Catha edulis plant (Khat) that contain Cathinone were consumed daily in Yemen as a social habit for the mild stimulant effect of cathinine. Chewing Khat has socio-cultural tradition in which consumers spend part of their time ranging between 4-8 hours per day, in chewing khat. This study aimed to investigate the changes in biochemical markers and antioxidants associated with chewing khat. The results showed a major alteration in the estimated biochemical and the antioxidant markers. It reveal that chewing khat has a toxic effect, on blood constituents, and induce the oxidative stress. The alteration in the clinical biomarkers could be an indicator for liver and kidney toxicity. These proposed that; the daily chewing khat for long time leads to alter in the biochemical composition of blood and enhancing oxidative state, these may contribute in the failure of the body organs, further detailed studies are recommended.

This investigation is aimed at studying the influence of different drying temperatures on the antioxidant activity for thyme leaves. In the present study different spectrophotometric methods (DPPH, FRAP) are using to investigate the antioxidant activities of thyme plants. The results showed that the drying temperature influences the antioxidant activity. The antioxidant activity of all studied extracts decreased with increasing temperature attending decreasing in total phenol. Fresh thyme shows the highest antioxidant activity (0.014 BHTE.mL-1, 0.0064 AAE and 0.0062 GAE).mL-1 extract and total phenol content (8.78 10-4 mol GAE and 7.50 10-3 mol AAE).mL-1 of extract. Whereas thyme dried at 40°C show the lowest antioxidant activity, (0.0042 BHTE, 0.0019 AAE and 0.0018 GAE).mL-1 of plant extract and total phenol contents (4.30 10-3 AAE and 4.68 10-4 GAE).mL-1 of plant extract.

Background The present study investigated the ameliorative effect of melittin, a major polypeptide in the venom of honeybee ( Apis mellifera ), on isoniazid-(INH) and rifampicin-(RIF) induced hepatotoxicity in male albino rats. Method Thirty rats (140-200 g) were divided into five groups ( n  = 6): normal control (NC) received normal saline orally (NaCl, 0.9%; toxic (T) group received INH + RIF (each rat received 100 mg/kg, p.o.); melittin (Mel15, Mel30) groups (each rat received 15 or 30 μg/kg s.c); and normal recovery (NR) group received INH + RIF (each rat received 100 mg/kg, p.o.). Blood and liver samples were collected for biochemical, hematological and histopathological studies respectively. Results The administration of melittin was found to prevent the antitubercular drug-induced alterations in the diagnostic markers; reduced glutathione (GSH), direct bilirubin (DB), total bilirubin (TB), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase...

Paracetamol has emerged as an important environment pollutants due to its wide usage. This study carried out to isolate and identify of a novel paracetamol-degrading bacteria from the contaminated site of pharmaceutical wastewater at Sana’a City, Yemen. The enrichment media and selective media were used to isolate and purify the bacteria from wastewater samples. The isolated bacteria were identified according to phenotypic and genotypic characterization using 16S rRNA sequence analysis. The results showed that the three bacterial strains and signed as an STB1, STB3 and STB5. The STB1 strain was identified as Pseudomonas aeruginosa strain DSM 50071 with similarity 92%, while the STB3 and STB5 were identified as P. aeruginosa strain NBRC 12689 with similarity 89% and 99%, respectively. The optimal conditions for paracetmol degradation by all stains were recorded at 30 ̊C and pH 7.0. Also, the paracetamol degradation was found to be influenced by an increase in the bacterial cell conce...

Objective The present study aimed to investigate the ameliorative effect of melittin, a major polypeptide in the venom of honeybee (Apis mellifera) on isoniazid (INH) and rifampicin (RIF) induced hepatotoxicity in male albino rats. Method: The rats (140-200g) were divided into five groups (n=6): normal control (NC); toxic (T) group treated with INH+RIF (100 mg/kg, p.o.); melittin-treated (Mel15, Mel30) group (15 or 30 µg/kg s.c); and normal recovery (NR) group. Blood and liver samples were collected for biochemical, hematological and histopathological studies respectively. Results The administration of melittin was found to prevent the antitubercular drug-induced alterations in the diagnostic markers; reduced glutathione (GSH), direct bilirubin (DB), total bilirubin (TB), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and total serum protein (TSP). Besides, hematological alterations were significantly high (...

Abstract Pure Aspirin samples were treated with a wide spectrum of light (γ-ray, UV- lamp and sunlight) and 40 °C temperature at various time of exposure. The changes in the thermal degradation parameters, crystalline structure, morphology and purity due to radiation and temperature treatments of Aspirin were pursued by comparing their TGA, XRD, SEM and HPLC results. The non-isothermal thermogravimetric analysis curves (TG, DTG and DSC) at 10 °C min−1 heating rate, under nitrogen flow and overheating range of 25–650 °C showed two degradation steps for the treated and untreated Aspirin samples. Accordingly, their thermal behavior and thermal stability were determined. Aspirin samples treated with 40 °C and UV-12 h were proven to be of the lowest thermal stability as their TDTG values (166.7 and 168.8 °C) were lower than that of the untreated sample (TDTG = 181 °C). The degradation kinetics parameters (i.e. activation energy, pre-exponential factor and order of reaction), life time prediction and thermodynamic parameters (ΔG*, ΔH* and ΔS*) were worked out using the Coats-Redfern (CR) expression and standard equations. The lowest activation energy (104.3 kJ mol−1) associated with the highest degradation rate was observed for the UV-12 h treated Aspirin sample. Crystallinity percentage was estimated from XRD and DSC, whereas, morphology and purity changes due to treatments were detected by scanning electron microscopy (SEM) and HPLC. The significant change in crystallinity from the XRD results of the treated Aspirin samples occurred in the (32.2%–58.7%) range. The photocatalytic degradation of Aspirin samples before and after treatments was carried out using TiO2/sunlight system. The photocatalytic degradation of all samples followed pseudo first order kinetics and the shelf life, rate of reaction and efficiency of degradation were determined and discussed. The highest degradation percentage (∼99%) and the associated lowest shelf life (4.3–5.8 min) were observed in the photocatalytic degradation of the 40 °C, UV-12 h, γ-ray-aqueous and sunlight treated samples.

Accumulation of reactive oxygen species (ROS) is a predominant behavior in the most plants when subjected to any abiotic stresses. Seedlings of horse gram tissue culture stressed by dehydration responded by expression of a new isoform of guaiacol peroxidase (GPOX) comparison with unstressed seedlings. This new GPOX was purified by passing the ammonium sulfate fraction of extract through 7-12 % gradient resolving gel of PAGE at 4 °C. A small part of the gel was cut and subjected to activity staining of peroxedase. By aligning the stained and unstained gels, the portion of unstained gel corresponding to the enzyme band have been excised. The enzyme was recovered by electro-eluting technique using Tris buffer, pH 6.8 for 45 min, and partially characterized. The purified GPOX has approximately 43 kD molecular mass; it was stable at low pH and it was maximally active at pH 6. The enzyme was more sensitive to high temperature, and its optimum temperature was at room temperature. Kinetic c...

Objectives: Reactive oxygen species (ROS) have been implicated in the development of streptozotocin (STZ)-induced diabetes mellitus. Secoisolariciresinol diglucoside (SDG) isolated from flaxseed is an antioxidant. An investigation was made of the effects of SDG on the development of STZ-induced diabetes in rat, to determine if SDG can prevent/reduce the development of diabetes and if this prevention/reduction is associated with reduction

Physical weathering of parent rocks, mining, and other anthropogenic activities lead to impermissible levels of heavy metals in plant tissues. Effect of Cd 2+ , Hg 2+ , and Zn 2+ on metabolic enzymes, Amylase (EC; 3.2.1.1), and AP (EC; 3.1.3.2), were studied to assess horse gram response to these heavy metal stress. Enzyme activity and TC were evaluated. Amylase decreased in response to increasing Cd 2+ concentration, with great impact at 48-72h. It rose under 5 ppm Hg 2+ , while dropped under 10 ppm beyond 24h reaching ~25% of control, and recovered with time to reach 80-90% under 20 ppm. Under Zn 2+ stress, amylase rose in concentration-and time-dependent manner. AP declined under metal stress in concentration, time-dependent manner, except at 100 ppm Zn 2+. TC fluctuated in metal-specific manner with positive influence by Zn 2+ (300-600 ppm) and Cd 2+ (100-200 ppm) at 24 h. TC diminished under Cd 2+ stress beyond 24 h, and over entire duration under Hg 2+ stress. It can deduce that Hg 2+ and Cd 2+ exhibited toxic effects on horse gram while Zn 2+ had positive effects. Amylase responded negatively to Hg 2+ , positively to Zn 2+ , and showed mixed response to Cd 2+. AP levels decreased under metal stresses, except Zn 2+ .

Khat, is one of the major economic, social and health problems facing Yemen. This project aims to study the effect of khat on some biochemical processes and the oxidative situation in human by measuring the amount of creatinine, urea, uric acid, in addition to measuring the activity of Catalase (CAT) in blood of 50 individual’s daily chewing khat and 20 of individuals do not chew khat as a Control. All of individuals were healthy and do not suffer from any hereditary diseases or chronic symptoms. According to their ages they divided into two groups; A representing those aged between 20-30 and B those aged between 31- 40 years. The results showed elevation of creatinine by 30% in group A (P> 0.01) while B has shown a little difference compared with the reference while the urea elevated by 30% (P> 0.0014) for both groups. Uric acid significantly elevated by 40% in Group A and 25% in B (P> 0.049) compared with the reference samples, this is consistent with previous studies tha...

The responses of horse gram, well known for its performance under drought conditions, to the applied stress were evaluated in terms of antioxidants and antioxidant enzymes. The antioxidant Proline, Ascorbic acid showed marked elevation, whereas glutathione content was marginally elevated during the stress. Antioxidant enzymes such as peroxidase (POX) glutathione reductase (CR) showed significant increase while catalase (CAT) and ascorbic peroxidase (APX) were reduced to one half of the controls. In addition other stress specific parameter such as chlorophyll and total sugar, were employed to know the prevailing stress response pathway .while total chlorophyll was reduced to 3/3 of control, no significant change in total sugar was noted. Malondialdehyde (MDA) widely regarded as an indicator of oxidative stress damage to cellular membrane, but not as a signal of stress Increased up to 25% of control, further suggested production and accumulation of ROS and consequent production of ant...

Effects of drought on horse gram seedlings were investigated for both normal and tissue culture regenerated plants. Biochemical response of tissue culture regenerated plants stressed with dehydration also behaved similar to drought stressed seedlings in terms of antioxidant enzymes and antioxidants albeit minor variations. Levels of antioxidant enzymes activity in tissue culture and normal seedlings relative to their controls showed a similar trend. Superoxide dismutase (SOD) and Glutathione reductase (GR) were elevated under stress in both seedlings. However, the Catalase (CAT) levels were reduced in both the tissues under applied stress. Although peroxidase (POX) level in both stressed tissues elevated, stressed tissue culture seedlings showed a new peroxidase isoform. In comparison with the controls tissue culture plantlets, the stressed plantlets had 2-fold increase in H2O2, Malondialdehyde (MDA), and ascorbic acid, ~3-fold increase in glutathione (GSH) and a 6-fold increase in ...

Temperature stress causes ROS in plants, and plants adapt to stress by producing antioxidants and antioxidant enzymes and stress specific proteins. Seedlings of horse gram a well-known drought resistance plant were subjected to high temperature stress at relative humidity. To understand the biochemical basis of heat response stress enzymes peroxidase and acid phosphatase were significantly elevated while amylase was not affected by heat stress. There were significant differences in intensities of isozymes of stressed seedlings relative to control SDS-PAGE patterns indicate six new proteins, which appeared during stress response. Antioxidants such as proline, ascorbate and ROS signal molecule H2O2 contents showed two-fold increase in stressed seedlings. Estimation of dry weight, and chlorophyll content revealed that drop in fresh mass, chlorophyll, while no change was observed in dry weight. From these observations it is intended to understand the possible contribution of antioxidant...

Exposure of plants to abiotic environmental factors such as drought, high temperature and salinity result in production and accumulation of reactive oxygen species (ROS). Plants have evolved both enzymatic and non-enzymatic mechanisms to scavenge and detoxify ROS. While enzymatic scavenging system involve SOD, CAT, APX, MDHAR, DHAR, GPX, and GR, non-enzymatic antioxidants involve pigments, vitamin-E, ascorbic acid, tocopherol, and GSH. Although responses to temperature, drought and salinity are physiologically linked, and involve ionic and osmotic homeostasis, biochemical markers of individual stress response are variable. In order to explore the signaling/response components, in horse gram, a well-know drought resistant crop, seedlings were subjected to high temperature stress (HTS) and salinity. Comparison of the enzymatic and non-enzymatic antioxidant components during temperature and salt stress is presented herein. In both, salt and high temperature stress, oxidative damage was...

The α-amylase from local Yemeni bean (Dolichos Lablab) seeds was partially purified by
conventional methods of protein purification such as pH and thermal precipitation, ammonium
sulphate fractionation and ion-exchange chromatography on DEAE-Cellulose. Native
Polyacrylamide Electrophoresis revealed that cashed α-amylase had isoform AmyI and AmyII.
The enzyme AmyII showed the following characteristics: optimum pH 7.0, optimum temperature,
Km value for hydrolyzing starch was 1.25 mg. The affinity between substrate and enzyme was
detected only for glycogen and starch compared with other carbohydrates tested, where
glycogen had more affinity than starch. Enzyme activity was stimulated by Ca2+, Ni2+ and Cd2+,
inhibited by Zn2+ and Hg2+. In conclusion, this α-amylase from Yemeni seeds have interesting
characteristics such as low km value, neutral pH optimum, high optimum temperature, high
affinity toward starch and glycogen and activation by some metal as calcium. Therefore, these
meet the prerequisites need for food industry.

High temperature and salinity are the major ecological factors challenging crop productivity in the arid and semiarid regions of the world. Effects of high temperature (43-45°C) and salt stress (0.6 M) on Macrotyloma uniflorum (Lam.) Verdc. (Horse gram), were evaluated in terms of antioxidants and antioxidant enzymes. Both treatments caused typical stress responses in this tropical leguminosae. Oxidative stress indicators such as H2 O2 , TBARS, and proline were significantly elevated. Similarly, the antioxidant enzymes superoxide dismutase (SOD; EC 1.15.1.1), guaiacol peroxidase (POX; EC 1.11.1.7) and acid phosphates (AP; EC 3.1.3.2) were significantly elevated while catalase (CAT; EC 1.11.1.6) was reduced. These treatments had contrasting effects on glutathione reductase (GR; EC1.6.4.2) and b-amylase (EC 3.2.1.1). While temperature stress caused increase in GR and decrease in b-amylase, salt stress caused a counter effect. Contrast was also observed in ascorbate and glutathione which increased in temperature stress and reduced in salt stress. SDS-PAGE analysis indicated entirely different protein profiles in temperature and salt stressed seedlings. Growth rate and fresh mass were affected to same extent, relative to their controls. Taken together these data describes the similarities and peculiarities of key biochemical responses of Horse gram to high temperatures and salinity.

Accumulation of reactive oxygen species (ROS) is a predominant behavior in the most plants when subjected to any abiotic stresses. Seedlings of horse gram tissue culture stressed by dehydration responded by expression of a new isoform of guaiacol peroxidase (GPOX) comparison with unstressed seedlings. This new GPOX was purified by passing the ammonium sulfate fraction of extract through 7-12 % gradient resolving gel of PAGE at 4 °C. A small part of the gel was cut and subjected to activity staining of peroxedase. By aligning the stained and unstained gels, the portion of unstained gel corresponding to the enzyme band have been excised. The enzyme was recovered by electro-eluting technique using Tris buffer, pH 6.8 for 45 min, and partially characterized. The purified GPOX has approximately 43 kD molecular mass; it was stable at low pH and it was maximally active at pH 6. The enzyme was more sensitive to high temperature, and its optimum temperature was at room temperature. Kinetic constants were determined, Km values was 15 mM and 0.6 mM of for guaiacol and H2O2 respectively while Vmax was 582.9 U/mg for guaiacol and 122.5 U/mg for H2 O2. The Km values indicate that the enzyme is highly specific to hydrogen peroxide and showed higher substrate affinity than previously reported GPOXs. This fact suggest that the new isoform of GPOX which expressed during dehydration stress is as part of the defense system in the plant which may enhance scavenging of ROS and assist the stressed plant to keep survive.