Guanine quadruplexes and their roles in molecular processes.

The role of guanine quadruplexes (G4) in fundamental biological processes like DNA replication, transcription, translation and telomere maintenance is recognized. G4 structure dynamics is regulated by G4 structure binding proteins and is thought to be crucial for the maintenance of genome integrity in both prokaryotic and eukaryotic cells. Growing research over the last decade has expanded the existing knowledge of the functional diversity of G4 (DNA and RNA) structures across the working models. The control of G4 structure dynamics using G4 binding drugs has been suggested as the putative targets in the control of cancer and bacterial pathogenesis. This review has brought forth the collections of recent information that indicate G4 (mostly G4 DNA) roles in microbial pathogenesis, DNA damaging stress response in bacteria and mammalian cells. Studies in mitochondrial gene function regulation by G4s have also been underscored. Finally, the interdependence of G4s and epigenetic modifications and their speculated medical implications through G4 interacting proteins has been discussed.

FrnE, a cadmium-inducible protein in Deinococcus radiodurans, is characterized as a disulfide isomerase chaperone in vitro and for its role in oxidative stress tolerance in vivo.

Deinococcus radiodurans R1 exposed to a lethal dose of cadmium shows differential expression of a large number of genes, including frnE (drfrnE) and some of those involved in DNA repair and oxidative stress tolerance. The drfrnE::nptII mutant of D. radiodurans showed growth similar to that of the wild type, but its tolerance to 10 mM cadmium and 10 mM diamide decreased by ~15- and ~3-fold, respectively. These cells also showed nearly 6 times less resistance to gamma radiation at 12 kGy and ~2-fold-higher sensitivity to 40 mM hydrogen peroxide than the wild type. In trans expression of drFrnE increased cytotoxicity of dithiothreitol (DTT) in the dsbA mutant of Escherichia coli. Recombinant drFrnE showed disulfide isomerase activity and could maintain insulin in its reduced form in the presence of DTT. While an equimolar ratio of wild-type protein could protect malate dehydrogenase completely from thermal denaturation at 42 °C, the C22S mutant of drFrnE provided reduced protection to malate dehydrogenase from thermal inactivation. These results suggested that drFrnE is a protein disulfide isomerase in vitro and has a role in oxidative stress tolerance of D. radiodurans possibly by protecting the damaged cellular proteins from inactivation.

Oxidative stress in spinal cord injury and antioxidant-based intervention.

STUDY DESIGN: Literature review. OBJECTIVES: Spinal cord injury (SCI) remains a major public health issue in developed countries as well as worldwide. The pathophysiology of SCI is characterized by an initial primary injury followed by secondary deterioration. Although the etiology and pathogenesis of SCI remain to be fully understood, it has been suggested that reactive oxygen species (ROS) and oxidative stress have a significant role in the pathophysiology of SCI. Thus, alleviating oxidative stress may be an effective strategy for therapeutic intervention of SCI. The aim of this review was to describe (i) the sources of ROS as well as the major antioxidant defenses with particular attention being paid to lipid peroxidation; (ii) the biomarkers of oxidative stress in SCI and (iii) the neuroprotective effects of various compounds with antioxidative properties in animal models of SCI. METHODS: PubMed, one of the most comprehensive biomedical databases, was searched from 1976-2011. All relevant papers were read by title, abstract and full-length article. RESULTS: Oxidative stress is considered a hallmark of injury of SCI. Thus, alleviating oxidative stress may be an effective way of therapeutic intervention of SCI. Two of these agents, the glucocorticoid steroid methylprednisolone and the non-glucocorticoid 21-aminosteroid tirilazad, have been shown to possess significant antioxidant activities and improve recovery of SCI patients in clinical trials. Other promising botanical compounds and their molecular targets and mechanisms of action with regard to potential protection against SCI were also described. These include carotenoids and phenolic compounds. CONCLUSION: ROS and oxidative stress have a significant role in the pathophysiology of SCI. Alleviating oxidative stress is be an effective strategy for therapeutic intervention of SCI. Extensive research over the past several decades has identified numerous bioactive compounds that have antioxidative stress benefits in animal models of SCI. Thus, continued studies on bioactive compounds with ROS-scavenging capacity may lead to the development of effective antioxidant-based modalities for treating SCI in human subjects.

Comparative genetic analysis of trichome-less and normal pod genotypes of Mucuna pruriens (Fabaceae).

Velvet bean (Mucuna pruriens) seeds contain the catecholic amino acid L-DoPA (L-3,4-dihydroxyphenylalanine), which is a neurotransmitter precursor and used for the treatment of Parkinson's disease and mental disorders. The great demand for L-DoPA is largely met by the pharmaceutical industry through extraction of the compound from wild populations of this plant; commercial exploitation of this compound is hampered because of its limited availability. The trichomes present on the pods can cause severe itching, blisters and dermatitis, discouraging cultivation. We screened genetic stocks of velvet bean for the trichome-less trait, along with high seed yield and L-DoPA content. The highest yielding trichome-less elite strain was selected and indentified on the basis of a PCR-based DNA fingerprinting method (RAPD), using deca-nucleotide primers. A genetic similarity index matrix was obtained through multivariant analysis using Nei and Li's coefficient. The similarity coefficients were used to generate a tree for cluster analysis using the UPGMA method. Analysis of amplification spectra of 408 bands obtained with 56 primers allowed us to distinguish a trichome-less elite strain of M. pruriens.

Coronavirus disease 2019: scientific overview of the global pandemic.

Coronavirus disease 2019 (COVID-19) is the disease caused by the novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Genome sequencing of the virus revealed that it is a new zoonotic virus that might have evolved by jumping from bats to humans with one or more intermediate hosts. The immediate availability of the sequence information in the public domain has accelerated the development of quantitative RT-PCR-based diagnostics. Numerous clinical trials have been prioritized globally for testing new vaccines and treatments against this disease. This review provides a broad insight into different aspects of COVID-19, an introduction to SARS-CoV-2 mitigation strategies and the present status of diagnostics and therapeutics.

N-terminal domain of DivIVA contributes to its dimerization and interaction with genome segregation proteins in a radioresistant bacterium Deinococcus radiodurans.

Unlike in rod-shaped bacteria, cell polarity is not well defined in cocci and possibly gets marked during molecular events around cytokinesis. DivIVA is a member of Min system that is involved in spatial regulation of septum formation in bacteria. Recently, we showed that DivIVA of Deinococcus radiodurans (drDivIVA) interacts with proteins involved in cell division and genome segregation (segrosome). To map drDivIVA domain (s) that interact with these proteins, the N-terminal (DivIVA-N), C-terminal (DivIVA-C) and a middle (DivIVA-M) region/section of drDivIVA were generated. Circular Dichroism (CD) studies suggested that all three variants of drDivIVA fold properly, but they appeared different under transmission electron microscopy (TEM). Full length drDivIVA showed bundles under TEM whereas variants did not. Both full length drDivIVA and N-terminal domain showed repeats of heptad motifs, a characteristic of alpha-helical coiled-coil proteins. DivIVA-N showed dimerization and interaction with segrosome while DivIVA-M interacted with MinC, a cell division regulatory protein. Further, the C-terminal region seems to be crucial for the structural and functional integrity of drDivIVA. These results suggested that drDivIVA dimerizes through its N-terminal domain while both segrosome and MinC interact through different regions of this protein.

The role of superoxide anion generation in phagocytic bactericidal activity. Studies with normal and chronic granulomatous disease leukocytes.

The capacity of human phagocytes to generate superoxide anion (O2-), a free radical of oxygen, and a possible role for this radical or its derivatives in the killing of phagocytized bacteria were explored using leukocytes from normal individuals and patients with chronic granulomatous disease (CGD). Superoxide dismutase, which removes O2-, consistently inhibited phagocytosis-associated nitroblue tetrazolium (NBT) reduction indicating the involvement of O2- in this process. Similarly, superoxide dismutase inhibited the luminescence that occurs with phagocytosis, implicating O2- in this phenomenon, perhaps through its spontaneous dismutation into singlet oxygen. Subcellular fractions from homogenates of both normal and CGD leukocytes generated O2- effectively in the presence of NADH as substrate. However, O2- generation by intact cells during phagocytosis was markedly diminished in nine patients with CGD. Leukocytes from mothers determined to be carriers of X-linked recessive CGD by intermediate phagocytic reduction of NBT elaborated O2- to an intermediate extent, further demonstrating the interrelationship between NBT reduction and O2- generation in phagocytizing cells. Activity of superoxide dismutase, the enzyme responsible for protecting the cell from the damaging effects of O2-, was approximately equal in homogenates of normal and CGD granulocytes. Polyacrylamide electrophoresis separated this activity into a minor band that appeared to be the manganese-containing superoxide dismutase associated with mitochondria and a more concentrated, cyanide-sensitive, cytosol form of the enzyme with electrophoretic mobility that corresponded to that of erythrocyte cuprozinc superoxide dismutase. Superoxide dismutase inhibited the phagocytic killing of Escherichia coli, Staphylococcus aureus, and Streptococcus viridans. A similar inhibitory effect was noted with catalase which removes hydrogen peroxide. Neither enzyme inhibited the ingestion of bacteria. Peroxide and O2- are believed to interact to generate the potent oxidant, hydroxyl radical (.OH). A requirement for .OH in the phagocytic bactericidal event might explain the apparent requirement for both O2- and H2O2 for such activity. In agreement with this possibility, benzoate and mannitol, scavengers of .OH, inhibited phagocytic bactericidal activity. Generation of singlet oxygen from O2- and .OH also might explain these findings. It would seem clear from these and other studies that the granulo cyte elaborates O2- as a concomitant of the respiratory burst that occurs with phagocytosis. To what extent the energy inherent in O2- is translated into microbialdeath through O2- itself, hydrogen peroxide, .OH, singlet oxygen, or some other agent remains to be clearly defined.

Xanthomonas caspase displays an inherent PARP-like activity.

In an earlier study, intracellular accumulation of metabolites such as pyruvate and citrate in Xanthomonas campestris pv. glycines (Xcg) was found to result in a caspase dependent stationary phase rapid cell death (RCD). In the present study, the presence of poly ADP-ribose polymerase (PARP)-like activity associated with caspase-3-like protein of Xcg is reported. This activity was found to be responsible for depletion of cellular NAD(+) levels in RCD-promoting media such as Luria-Bertani medium and starch medium fortified with citrate. Addition of PARP-specific inhibitors such as 3-aminobenzamide to RCD-promoting media restored the intracellular NAD(+) levels and thereby prevented RCD. The inherent association of PARP-like activity with the caspase protein was demonstrated by PARP cellular assay, immuno-precipitation and Western analysis. A truncated polysaccharide deacetylase gene having a caspase-like domain was cloned. The expressed protein though found to be inactive, cross-reacted with human caspase and PARP antibodies. This is the first report demonstrating the presence of a PARP-like activity in a prokaryote and its involvement in cell death.

Pharmacokinetics in patients of an anti-carcinoembryonic antigen antibody radiolabeled with indium-111 using a novel diethylenetriamine pentaacetic acid chelator.

The pharmacokinetics of the C110 anti-carcinoembryonic antigen antibody radiolabeled with 111In via a novel benzylisothiocyanate derivative of diethylenetriamine pentaacetic acid have been determined in 12 patients. The chelator was attached to the protein via a thiourea bond and in such a way that all 5 carboxymethyl arms were presumably able to participate in chelation. Patients with known or suspected colorectal carcinoma received between 5 and 20 mg of the IgG antibody labeled with 5 mCi of 111In. Individual organ radioactivity levels were quantitated, and serum and urine samples were analyzed, principally by size exclusion high-performance liquid chromatography (HPLC). Total urinary excretion averaged 0.18% of the injected dose/h with large patient to patient variation. At early times postadministration (less than 8 h) the predominant radiolabeled species in urine was free diethylenetriamine pentaacetic acid most probably administered as a small radiocontaminant in the injectate. Thereafter, radioactivity in urine was primarily present as a low molecular weight catabolic product. Analysis of serum by size exclusion HPLC occasionally showed 3 radioactivity peaks, 2 of which are due to circulating immune complexes and labeled antibody. The third peak is of low molecular weight and is due to one or more products of antibody catabolism. Transchelation of 111In to circulating transferrin was observed but at modest levels. Quantitation of organ radioactivity showed that 18 +/- 4 (SD)% of the injected dose was in the liver at 1 day postadministration and 1.4 +/- 1.1 and 1.2 +/- 0.9% was in the spleen and in both kidneys, respectively, at this time. The mean half-life for clearance of total injected radioactivity was fitted to a single exponential and was found to be 34 h (SD, 14 h; N = 13) and that for antibody alone, assessed by size exclusion HPLC analysis of serum samples, was calculated to be 22 h (SD, 8 h; N = 10). Neither of these values nor organ radioactivity levels were affected by antibody-loading dose.

The purification and properties of superoxide dismutase from a blue-green alga.

Soluble extracts of Plectonema boryanum have been shown to contain a single, electrophoretically distinct, superoxide dismutase. The enzyme has been isolated and has been found to be an iron-containing enzyme similar to that described from the periplasm of Escherichia coli. It contains 1 Fe3+/mole of enzyme. The molecular weight was approximately 36 500, and the enzyme appeared to be composed of two subunits of equal size joined by non-covalent interactions. ESR data are presented, as are the results of amino acid analysis.

Excitation energy transfer from phycobilisomes to photosystems: a phenomenon associated with the temporal separation of photosynthesis and nitrogen fixation in a cyanobacterium, Plectonema boryanum.

Plectonema boryanum shows temporal separation of photosynthesis and nitrogen fixation under diazotrophic conditions. Low temperature fluorescence studies have shown that in vivo the nitrogen fixing and photosynthesizing cells are adapted to 'state 2' and 'state 1', respectively. During nitrogen fixation phycobilisomes seem to transfer excitation energy to photosystem I whereas during oxygenic photosynthesis the energy is transferred to photosystem II. The state 2 adapted N-phase cells failed to undergo transition to state 1 while P-phase cells exhibited state 1 to state 2 transition. The nitrogen fixing cells showed a decreased level ofpsbC transcript, lack of CP47 in thylakoid membrane, and presence of the F685 peak but absence of the F695 peak in 77 K fluorescence spectra. These results suggest that the metabolic and molecular changes associated with nitrogen fixation may favor direct energy transfer from the phycobilisomes to photosystem I. This should help the organism to achieve low photosystem II and high photosystem I activity to set temporal separation of nitrogen fixation and photosynthesis for photoautotrophic growth under diazotrophic conditions.

Structural modifications at the 2'- and 3'-positions of some pyrimidine nucleosides as determinants of their interaction with the mouse erythrocyte nucleoside transporter.

Modifications in the sugar moiety of pyrimidine nucleosides may affect their ability to function as permeants of the mouse erythrocyte nucleoside transporter. In this investigation, a number of synthetic uracil and thymine nucleosides which differ from the physiological nucleosides, uridine, deoxyuridine and thymidine, through structural changes at the 2'- and 3'-positions were studied. Interaction of the analogs with the transporter has been assessed in terms of their affinities for an external site on the transporter as well as their abilities to effect trans-acceleration of thymidine efflux. 1-(beta-D-Arabinofuranosyl) uracil (araU) and 1-(beta-D-arabinofuranosyl)thymine (araT) were comparable to thymidine as permeants while nucleosides in which the 3'-hydroxyl was replaced with hydrogen or a halogen had a decreased affinity for the transporter. 3'-Fluoro-3'-deoxy-araU weakly accelerated thymidine efflux while its ribo-isomer and the other 3'-halogeno-3' deoxy-arabino analogs as well as dideoxythymidine inhibited efflux. The absence of 2'- and 3'-carbons in acyclothymidine and acyclouridine strongly decreased the affinities of these nucleosides for the transporter; efflux of thymidine was not accelerated in the presence of these compounds. The conformationally constrained cyclic nucleoside 2,2'-anhydro-araU had a very low affinity for the transporter, and influx of the radiolabeled compound could not be demonstrated. The results suggest that modification at the 3'-position, loss of a portion of the sugar ring, and lack of conformational flexibility are factors which decrease the abilities of some pyrimidine nucleosides to function as permeants. It is suggested that combined effects of substituents which play a role in determining nucleoside conformation should be considered in assessing structural requirements for permeants of the transporter.

Amelioration of postischemic reperfusion injury by antiarrhythmic drugs in isolated perfused rat lung.

Antiarrhythmic drugs, such as lidocaine, quinidine, and procainamide, have been shown to be effective against postischemic reperfusion injury in isolated rat lungs. Rat lungs were perfused at a constant flow with Krebs-Henseilet buffer supplemented with 4% bovine serum albumin and ventilated with air containing 5% CO2. The lungs were subjected to ischemia by stopping perfusion and ventilation for 60 min followed by 30 min of reperfusion. Lung injury was determined by measuring the increase in wet-to-dry lung weight ratio, while pulmonary arterial pressure and peak airway pressure were calculated from the pre- and postischemic differences. Lidocaine, quinidine, and procainamide at doses of 5, 10, and 20 mg/kg body weight, respectively, were found to attenuate the postischemic lung injury significantly (p < 0.0001). The formation of cyclooxygenase products, which were elevated during reperfusion, was also significantly (p < 0.0001) inhibited by these drugs. Since these antiarrhythmic agents are found to be powerful scavengers of hydroxyl radicals and can prevent membrane lipid peroxidation, these findings suggest that the antioxidant properties of these drugs may, in part, be responsible for protecting the lungs against reperfusion injury.

A double-blind comparison of naproxen with indomethacin in osteoarthrosis.

Twenty-two patients with osteoarthrosis of one or both knee joints and 28 patients with osteoarthrosis of one or both hips completed a double-blind trial of 500 mg naproxen daily versus 100 mg indomethacin daily. All patients had been on other active medication up to the start of the trial. Identical trial designs were followed with both classes of patients, namely, a crossover pattern of four weeks on each drug with patients being assessed at -2, 0, 2, 4, 6, and 8 weeks. Assessments made included objective measurement of joint range, stair climbing and walking times, and subjective grading of pain present during normal activity, of which the patient kept a daily record. Patients were also questioned at each clinic visit regarding possible side effects. Study groups were comparable for both drugs. In the majority of subjective and objective parameters, there were significant improvements from baseline on both drugs of statistically comparable magnitude. Significantly fewer side effects were noted during the period on naproxen compared with those on indomethacin. There were no abnormalities discovered in hematologic or biochemical tests performed during the course of the trial.

Vasoactive intestinal polypeptide relaxes pulmonary artery by an endothelium-independent mechanism.

Vasoactive intestinal polypeptide (VIP) is a potent endogenous vasodilator. VIP-induced vasodilation is independent of adrenergic or cholinergic receptors and, for the most part, of arachidonate metabolites, but its mechanism is still unknown. In view of the recently demonstrated essential role of endothelium in the relaxant effect of numerous vasodilators, we have investigated the importance of endothelium in the vascular relaxation induced by VIP. Vascular smooth muscle preparations were circular strips of the pulmonary artery of guinea pig, rat and rabbit, and rat thoracic aorta, previously contracted by a synthetic prostaglandin endoperoxide analog. VIP relaxed pulmonary artery of all species by an endothelium-independent mechanism, but relaxed rat thoracic aorta only in the presence of intact endothelium.

EPR studies of trapped singlet oxygen (1O2) generated during photoirradiation of hypocrellin A.

Hypocrellin A, a peryloquinone derivative, has recently been isolated from the sacs of the fungus Hypocrella bambusae. This pigment, in combination with phototherapy, has been used in human medicine to cure various skin diseases. The generation of singlet oxygen during photoirradiation of Hypocrellin A (HA) was detected as an oxidation product of a sterically hindered amine (tetramethylpiperidine oxide; TEMPO) by electron paramagnetic resonance (EPR) spectroscopic techniques. Azide inhibited the EPR signal intensity in a dose-dependent manner with a quenching rate constant of 3.86 x 10(8) M-1s-1 in ethanol. Deuterated solvents, known to increase the lifetime of singlet oxygen, augmented the EPR signal intensity. The rate of production of singlet oxygen was dependent not only upon the concentration of HA and the time of irradiation but also on the oxygen content of the reaction mixture. The hyperfine splitting constant (aN = 16.3 G) and g-value (g = 2.0056) of the photoproduct of TEMP-singlet oxygen and TEMPO were found to be identical. This indicates that the nitroxide species detected by EPR spectroscopy generated by reacting TEMP with photogenerated 1O2 is TEMPO. The rate constant (kT) for the reaction of singlet oxygen with TEMP to form TEMPO radical was found to be 5.3 x 10(5) M-1s-1.

Generation of free radicals during photosensitization of hypocrellin A and their effects on cardiac membranes.

Hypocrellin A (HA), a peryloquinone derivative, has recently been isolated from a fungus Hypocrella bambusae. This lipid soluble pigment, in combination with phototherapy, has been used to treat many skin diseases including the keloids caused by scalding and burns. We have studied the effects of photosensitized HA on biomembranes using pig heart microsomes. Photosensitization of HA was found to peroxidize the membrane lipids in the cardiac microsomes. The photodamage imposed by HA depended not only on the concentration of HA but also on the time of irradiation and pH of the system. Superoxide dismutase (SOD), ascorbic acid, beta-carotene and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) inhibited the lipid peroxidation approximately 50, approximately 50, approximately 30 and approximately 97%, respectively. Spin trapping in combination with EPR spectroscopic techniques was used to identify the reactive free radicals during the photoreaction. Formation of superoxide anion radical, (O2-.), was identified by the SOD-inhibitable DMPO-O2- EPR spectrum. Both SOD and ascorbic acid inhibited the EPR signal intensity in a dose-dependent manner with rate constants of 6.78 x 10(8) M-1 s-1 and 1.82 x 10(4) M-1 s-1, respectively. The lifetime of O2-., under these conditions, was found to be 1.1 s. Photoirradiation of HA yielded a HA free radical with a g = 2.002 which was not suppressed by SOD but in the presence of reductants such as ascorbic acid and catechol the septum was completely suppressed. The increase of the EPR signal intensity and malondialdehyde formation with increasing pH may be due, in part, to the production of predominant *HA- species at high pH which would be more reactive with oxygen to yield O2-.. These results indicate that the lipid peroxidation of the cardiac membranes observed during photooxidation of HA may arise, in part, from the interaction of membrane lipids with reactive species of oxygen and HA free radical produced during the photo-irradiation.

Revascularization of the limbs with urokinase and TEC catheter endarterectomy for occluded bypass grafts.

Occlusion of a femoral-popliteal or a femoral-tibial bypass graft on a prior occluded superficial femoral artery or the popliteal artery (in cases of ischemia of the legs) creates a complicated problem that may result in limb loss. The revascularization of such limbs with a repeat femoral-tibial or peroneal bypass is difficult and results in a high rate of limb loss from failure of the repeat grafts. Therefore, attempts were made to re-open the grafts through urokinase administration and thrombolysis for the grafts. To address the distal critical stenosis, or occlusion, the urokinase administration and thrombolysis were followed by endovascular endarterectomy using a thromboembolytic catheter (TEC). From 1990 to 1992, the above protocol was followed with 15 patients. In all patients, the protocol included 24 to 48 hours of urokinase administration with 60,000 to 120,000 U of urokinase per hour. A distal pathology was detected in all 15 patients, of whom 8 had complete occlusion at the site of distal anastomosis, 7 had critical stenosis ranging from 90% to 99%, and 1 was found to have a proximal critical stenosis at the femoral-graft junction. TEC catheter endarterectomy was performed to address the problem of occlusion and critically stenosed distal anastomotic lesions; a 100% success rate was immediately achieved, with flow being re-established to the distal limb. Fourteen of 15 patients remained well revascularized for more than 1 year. One patient experienced re-occlusion after 8 months; the occlusion was re-opened using the same technique of urokinase administration and the use of the TEC catheter, in which case the graft subsequently remained open. The longest follow-up of one patient is more than 2 years, during which time the graft has stayed open. With the aforementioned results, after revascularization of the ischemic limbs from occluded bypass grafts, it is strongly recommended that urokinase administration, along with TEC endovascular endarterectomy, be used to establish the circulation when occluded grafts threaten limb loss.

Superoxide dismutases of virulent and avirulent strains of Brucella abortus.

Extracts of Brucella abortus strains 2308,RB51,45/20 and ST 19 had no significant differences in superoxide dismutase (SOD) activity as measured by the epinephrine assay. These B. abortus strains represent smooth, intermediate and rough colony forms. SOD activity was inhibited 60 to 75% by 2 mM KCN and suggests the presence of Cu/Zn SOD. The SOD activities were similar when the strains were grown in trypticase soy broth containing either 0.5% glucose or erythritol. There were two distinct SOD activity bands in native polyacrylamide gel electrophoresis with identical mobilities for each of the strains. When the native gel was stained for SOD activities in the presence of 2 mM KCN, the SOD band that co-migrated with the bovine erythrocyte Cu/Zn SOD activity disappeared. The band of SOD activity that migrated similar to E. coli iron SOD activity was unaffected by KCN. There were no significant differences in either the total SOD or Cu/Zn SOD activities among the strains. As the Brucella strains represent ranges of virulence, it is difficult to associate any primary role for SOD as a virulence factor.

Synthesis and evaluation of substituted quinazolone derivatives for antibacterial, antifungal, and antiacetylcholinesterase activities.

The synthesis of new 6-bromo- and 6,8-dibromo-2-[N-(2'-alkyl-1',3',4'-thiadizol-5'-yl)carbamoylmethylthio] -3-aryl/cyclohexyl-4-(3H)-quinazolones is described. The synthesis derivatives were screened for antibacterial, antifungal, and antiacetylcholinesterase activities in vitro. Most of the compounds exhibited significant biological activity. The relation between their biological activity and chemical structure was studied.