Immune response, oxidative stress, and histological changes of Wistar rats after being administered with Parascaris equorum antigen.

Worldwide, particularly in developing nations, helminth infections are the leading causes of livestock illness and mortality. Parascaris (P.) equorum, a parasitic worm from the Ascarididae family, significantly impacts the production, health, and working performance of equines.

Mutational impact of APOBEC3A and APOBEC3B in a human cell line and comparisons to breast cancer.

A prominent source of mutation in cancer is single-stranded DNA cytosine deamination by cellular APOBEC3 enzymes, which results in signature C-to-T and C-to-G mutations in TCA and TCT motifs. Although multiple enzymes have been implicated, reports conflict and it is unclear which protein(s) are responsible. Here we report the development of a selectable system to quantify genome mutation and demonstrate its utility by comparing the mutagenic activities of three leading candidates-APOBEC3A, APOBEC3B, and APOBEC3H.

Inherent efficacies of pyrazole-based derivatives for cancer therapy: the interface between experiment and .

There has been an increasing trend in the design of novel pyrazole derivatives for desired biological applications. For a cost-effective strategy, scientists have implemented various computational drug design tools to go hand in hand with experiments for the design and discovery of potentially effective pyrazole-based therapeutics. This review highlights the milestones of pyrazole-containing inhibitors and the use of molecular modeling techniques in conjunction with experimental studies to provide a view of the binding mechanism of these compounds.

Mathematical Modeling of SARS-CoV-2 Transmission between Minks and Humans Considering New Variants and Mink Culling.

We formulated and studied mathematical models to investigate control strategies for the outbreak of the disease caused by SARS-CoV-2, considering the transmission between humans and minks. Two novel models, namely SEIR and SVEIR, are proposed to incorporate human-to-human, human-to-mink, and mink-to-human transmission. We derive formulas for the reproduction number R0 for both models using the next-generation matrix technique.

Purification, characterization, and enzyme kinetics of a glutathione S transferase from larvae of the camel tick Hyalomma dromedarii.

Background: Glutathione s-transferases (GSTs) perform an essential role in detoxification of xenobiotics and endogenous compounds via their conjugation to reduce glutathione.

Results: A GST enzyme, designated tick larvae glutathione S transferase (TLGST), was purified from larvae of the camel tick Hyalomma dromedarii via ammonium sulfate precipitation, glutathione-Sepharose affinity column and Sephacryl S-300 chromatography. TLGST-specific activity was found to be 1.

Characterization, antimicrobial and antitumor activity of superoxide dismutase extracted from Egyptian honeybee venom (Apis mellifera lamarckii).

Background: Superoxide dismutase is an important antioxidative stress enzyme which is found in honeybee venom and has a wide pharmaceutical and medical applications.

Results: We reported the purification and characterization of venom SOD from Egyptian honeybee Apis mellifera lamarckii and termed BVSOD. It was purified to homogeneity from the Egyptian honeybee venom.

Purification and characterization of thrombin from camel plasma: interaction with camel tick salivary gland thrombin inhibitor.

Background: Thrombin is the most important enzyme in the hemostatic process by permitting rapid and localized coagulation in case of tissue damage. Camel thrombin is the natural and proper target enzyme for the previously purified camel tick salivary gland thrombin inhibitor.

Results: In this study, the camel thrombin was purified homogenously in a single affinity chromatographic step on the heparin-agarose affinity column with a specific activity of 3242 NIH units/mg proteins.

A mathematical model for the spread of Varroa mites in honeybee populations: two simulation scenarios with seasonality.

We formulate and study a mathematical model for a honeybee colony infected with mites which describes the parallel phenomena of the spread of both the mites and the virus transmitted by them. We extend our previous model by including infected forager bees and considering model parameters as time-periodic functions. Firstly, we study the autonomous model and show the stability of equilibria.

XRCC1 counteracts poly(ADP ribose)polymerase (PARP) poisons, olaparib and talazoparib, and a clinical alkylating agent, temozolomide, by promoting the removal of trapped PARP1 from broken DNA.

Base excision repair (BER) removes damaged bases by generating single-strand breaks (SSBs), gap-filling by DNA polymerase β (POLβ), and resealing SSBs. A base-damaging agent, methyl methanesulfonate (MMS) is widely used to study BER. BER increases cellular tolerance to MMS, anti-cancer base-damaging drugs, temozolomide, carmustine, and lomustine, and to clinical poly(ADP ribose)polymerase (PARP) poisons, olaparib and talazoparib.

A seasonal model to assess intervention strategies for preventing periodic recurrence of Lassa fever.

Lassa haemorrhagic fever is listed in WHO's Blueprint priority list of diseases and pathogens prioritized for research and development, affecting several hundreds of thousands of people each year. Lassa fever is spread via infected Natal multimammate mice and also through human-to-human contacts and it is a particular threat to pregnant women. Despite its importance, relatively few mathematical models have been established for modelling Lassa fever transmission up to now.

Threshold Dynamics in a Model for Zika Virus Disease with Seasonality.

We present a compartmental population model for the spread of Zika virus disease including sexual and vectorial transmission as well as asymptomatic carriers. We apply a non-autonomous model with time-dependent mosquito birth, death and biting rates to integrate the impact of the periodicity of weather on the spread of Zika. We define the basic reproduction number [Formula: see text] as the spectral radius of a linear integral operator and show that the global dynamics is determined by this threshold parameter: If [Formula: see text] then the disease-free periodic solution is globally asymptotically stable, while if [Formula: see text] then the disease persists.

Phospholipase A2 enzyme from the venom of Egyptian honey bee Apis mellifera lamarckii with anti-platelet aggregation and anti-coagulation activities.

Background: Honey bee venom contains various enzymes with wide medical and pharmaceutical applications.

Results: The phospholipase A2 (PLA2) has been apparently purified from the venom of Egyptian honey bee (Apis mellifera lamarckii) 8.9-fold to a very high specific activity of 6033 U/mg protein using DEAE-cellulose and Sephacryl S-300 columns.

Enhancing the sensitivity of the thymidine kinase assay by using DNA repair-deficient human TK6 cells.

The OECD guidelines define the bioassays of identifying mutagenic chemicals, including the thymidine kinase (TK) assay, which specifically detects the mutations that inactivate the TK gene in the human TK6 lymphoid line. However, the sensitivity of this assay is limited because it detects mutations occurring only in the TK gene but not any other genes. Moreover, the limited sensitivity of the conventional TK assay is caused by the usage of DNA repair-proficient wild-type cells, which are capable of accurately repairing DNA damage induced by chemicals.

Apyrase with anti-platelet aggregation activity from the nymph of the camel tick Hyalomma dromedarii.

Apyrase is one of the essential platelet aggregation inhibitors in hematophagous arthropods due to its ability to hydrolyze ATP and ADP molecules. Here, an apyrase (TNapyrase) with antiplatelet aggregation activity was purified and characterized from the nymphs of the camel tick Hyalomma dromedarii through anion exchange and gel filtration columns. The homogeneity of TNapyrase was confirmed by native-PAGE, SDS-PAGE as well as with isoelectric focusing.

Impact of weather seasonality and sexual transmission on the spread of Zika fever.

We establish a compartmental model to study the transmission of Zika virus disease including spread through sexual contacts and the role of asymptomatic carriers. To incorporate the impact of the seasonality of weather on the spread of Zika, we apply a nonautonomous model with time-dependent mosquito birth rate and biting rate, which allows us to explain the differing outcome of the epidemic in different countries of South America: using Latin Hypercube Sampling for fitting, we were able to reproduce the different outcomes of the disease in various countries. Sensitivity analysis shows that, although the most important factors in Zika transmission are the birth rate of mosquitoes and the transmission rate from mosquitoes to humans, spread through sexual contacts also highly contributes to the transmission of Zika virus: our study suggests that the practice of safe sex among those who have possibly contracted the disease, can significantly reduce the number of Zika cases.

Thrombin inhibitor from the salivary gland of the camel tick Hyalomma dromedarii.

Blood-sucking arthropods have different types of anticoagulants to allow the ingestion of a blood meal from their hosts. In this study, five anticoagulants prolonging the activated partial thromboplastin time were resolved from the salivary gland crude extract of the camel tick Hyalomma dromedarii by chromatography on diethylaminoethyl (DEAE)-cellulose column. They were designated P1, P2, P3, P4 and P5 according to their elution order.

Intensive care unit nurses' perceptions of the obstacles to the end of life care in Saudi Arabia.

Objectives: To explore nurses' perceptions of obstacles to the provision of end of life care (EoLC) in the intensive care unit (ICU) in Saudi Arabia.

Methods: A modified version of a questionnaire developed by Beckstrand and Kirchhoff was administered in one setting at Riyadh, Saudi Arabia between March and April 2015.

Results: A total of 87 questionnaires were returned from 140 potential respondents, representing a 62% response rate.

Catalase from larvae of the camel tick .

Catalase plays a major role in protecting cells against toxic reactive oxygen species. Here, Catalase was purified from larvae of the camel tick and designated TLCAT. It was purified by ammonium sulfate precipitation and chromatography on DEAE-cellulose, Sephacryl S-300 and CM-cellulose columns.

Biochemical characterization of buffalo liver glucose-6-phosphate dehydrogenase isoforms.

Glucose-6-phosphate dehydrogenase (G6PD) is a key regulatory enzyme involved in the pentose phosphate pathway. This works represents purification of two buffalo liver glucose-6-phosphate dehydrogenases (BLG6PD1 and BLG6PD2) using combination of ammonium sulfate precipitation and several chromatographic columns. Both enzymes (BLG6PD1 and BLG6PD2) were homogenous on both native PAGE as well as 12% SDS PAGE with molecular weights of 28 and 66 kDa.

Purification and characterization of glucose-6-phosphate dehydrogenase from camel liver.

Glucose-6-phosphate dehydrogenase from camel liver was purified to homogeneity by ammonium sulfate precipitation and a combination of DEAE-cellulose, Sephacryl S-300 gel filtration, and 2', 5' ADP Sepharose 4B affinity chromatography columns. The specific activity of camel liver G6PD is increased to 1.80438 units/mg proteins with 63-fold purification.

Superoxide dismutases from larvae of the camel tick Hyalomma dromedarii.

Three superoxide dismutases (EC 1.15.1.

Structural insights into the South African HIV-1 subtype C protease: impact of hinge region dynamics and flap flexibility in drug resistance.

The HIV protease plays a major role in the life cycle of the virus and has long been a target in antiviral therapy. Resistance of HIV protease to protease inhibitors (PIs) is problematic for the effective treatment of HIV infection. The South African HIV-1 subtype C protease (C-SA PR), which contains eight polymorphisms relative to the consensus HIV-1 subtype B protease, was expressed in Escherichia coli, purified, and crystallized.

Comparison of the molecular dynamics and calculated binding free energies for nine FDA-approved HIV-1 PR drugs against subtype B and C-SA HIV PR.

We report the first account of a comparative analysis of the binding affinities of nine FDA-approved drugs against subtype B as well as the South African subtype C HIV PR (C-SA). A standardized protocol was used to generate the inhibitor/C-SA PR complexes with the relative positions of the inhibitors taken from the corresponding X-ray structures for subtype B complexes. The dynamics and stability of these complexes were investigated using molecular dynamics calculations.

Molecular mechanical perspective on halogen bonding.

The nature and strength of halogen bonding in halo molecule-Lewis base complexes were studied in terms of molecular mechanics using our recently developed positive extra-point (PEP) approach, in which the σ-hole on the halogen atom is represented by an extra point of positive charge. The contributions of the σ-hole (i.e.

AMBER empirical potential describes the geometry and energy of noncovalent halogen interactions better than advanced semiempirical quantum mechanical method PM6-DH2X.

A recently published study on halogen bonding in casein kinase 2 (CK2)-inhibitor complexes claimed that the halogen-bond-corrected PM6 semiempirical method (PM6-DH2X) describes the halogen bonding properties correctly, whereas the AMBER empirical potential fails. The current study employs our positive extra-point (PEP) approach for halogen bonding, in which the σ-hole on the halogen atom is represented by an extra point of charge. The performance of the two methods in describing halogen bonding in halobenzene···Lewis base and CK2-inhibitor complexes was reassessed.