Search

Today, the use of natural products and nanostructures has increased. Given the reports on beneficial effects of various organotellurane compounds on types of visceral leishmaniasis, we decided to investigate the effect of TeO2 NPs on Leishmania major (L. major). Tellurium can cause cell apoptosis in cancer cells without activating the caspase-pathway. TeO2 NPs at first synthesized and the structure was checked by XRD, SEM and EDS tests. The cytotoxic effect of TeO2 NPs against L. major promastigotes, amastigotes and macrophages was assessed by MTT test or counting. The possible apoptosis of L. major by TeO2 NPs was evaluated by flow cytometry test. For in vivo assay, the lesions of infected BALB/c mice with L. major promastigotes were treated with TeO2 NPs, then the lesion size and survival rate were evaluated. The synthesis of TeO2 with tetragonal structure was confirmed by XRD. The combination of nanorods and nanoflakes and the presence of Te were proven by SEM and EDS, respectively. According the effects of nanoparticle on promastigotes and amastigotes, the IC50 values of TeO2 after 72 h of incubation were 15.13 and 52.22 µg/ml, respectively. TeO2 NPs induced apoptosis in about 41% of promastigotes. The ulcer greatly healed and survival rate was higher in treated mice compared to those in control group. Based on the data, favorable anti-leishmanial properties were observed by using TeO2 NPs. TeO2 NPs have cytotoxic impacts on L. major promastigotes and amastigotes in vitro and in vivo and may be regarded as a therapy option.

Background Leishmaniasis is a neglected infectious disease caused by protozoa of the genus Leishmania. The disease generally manifests as characteristic skin lesions which require lengthy treatment with antimonial drugs that are often associated with adverse side effects. Therefore, a number of studies have focused on natural compounds as promising drugs for its treatment. This study aimed to evaluate the effects of larval excretion/secretion products (ES) of Lucilia sericata in crude and fractionated forms on Leishmania major, by using in vitro and in vivo models. Methods The in vitro experiments involved evaluation of ES on both promastigotes and macrophage-engulfed amastigotes, whereas the in vivo experiments included comparative treatments of skin lesions in L. major-infected mice with Eucerin-formulated ES and Glucantime. Results The half maximal inhibitory concentrations of the crude ES, > 10-kDa ES fraction, P Conclusions The present study showed that the larval ES of L. sericata in both crude and fractionated forms are effective for both intracellular and extracellular forms of L. major. Also, the ES exert both topical and systemic effects on mice experimentally infected with L. major. Graphical abstract

Attractive Toxic Bait (ATB) is a low risk practical method to cockroach control. This study aimed to evaluate efficacy of a newly modified eight-chamber-olfactometer for attractiveness experiments. Different stages of German cockroaches were exposed to carbohydrate-rich and protein-rich foods and their attractions were tested both at ambient conditions and in the modified olfactometer. In the latter method, cockroaches were released into the main chamber of olfactometer and their attraction to food compounds placed in test chambers were recorded as the number of captured cockroaches in test chambers. The direct attractiveness test was performed in plastic pans. Repellency of fipronil insecticide was performed with prepared bait powder using olfactometer. Data were subjected to analysis of variance with Tukey’s Test,P ≤ 0.05. Different notes should be considered when using introduced olfactometer like precision when opening the test chambers valves, the fan speed, placement of cardboard shelter in both test and main chambers, and initial starvation of cockroaches. Roasted peanut, banana and biscuits powder were the most attractive foods for cockroaches. The females significantly preferred roasted peanut and the males significantly preferred banana and roasted peanut. These results were similar to the results of direct attracted cockroaches. The cockroaches have repellency to fipronil but attractiveness of bait with 0.01% concentration was significantly higher than cockroach diet. Generally, three factors should be considered in formulation of ATB like un-repellency of the a.i, attractiveness of bait compositions, and palatability of bait texture. The olfactometer introduced in this study could be used by researchers to study cockroach behaviors.

In the present study, we evaluated induced immune responses following DNA vaccine containing cocktail or fusion of LeIF, LACK and TSA genes or each gene alone. Mice were injected with 100 µg of each plasmid containing the gene of insert, plasmid DNA alone as the first control group or phosphate buffer saline as the second control group. Then, cellular and humoral responses, lesion size were measured for all groups. All vaccinated mice induced Th1 immune responses against Leishmania characterized by higher IFN-γ and IgG2a levels compared with control groups (p

As an enzyme acting at the junction of gluconeogenic pathway, phosphoenolpyruvate carboxykinase (PEPCK) controls substrate flow from Krebs cycle toward glucose production. Therefore, it would be advantageous to design effective inhibitors to inactivate PEPCK in diabetes mellitus and other abnormalities caused by insulin resistance. Such inhibitors may compensate the metabolic consequences of ex-activity of PEPCK at these conditions. Understanding the mechanism by which inhibitors exert their effect on enzyme activity is of great interest for designing stronger inhibitors. In the present work, molecular dynamic simulations were used to study enzyme-inhibitor interactions. Our results indicate that inhibitors of PEPCK with their short chains interact with enzyme active site through non-covalent interactions of electrostatic and hydrogen bond nature. The data also show that inhibitors neither reach a stable state in their binding site nor make static complex with the enzyme active site. Instead, they interact with functional groups of active site residues in a dynamic fashion. In this way, oxalate and sulfoacetate carrying two negative groups of higher charge density and optimum spacing from each other, show more dynamic behavior (lower stability in their binding site) and more inhibitory effects than other inhibitors used (phosphonoformate, phosphoglycolate and 3-phosphonopropionate).

Background Among viral enzymes, the human HIV-1 protease comprises the most interesting target for drug discovery. There are increasing efforts focused on designing more effective inhibitors for HIV-1 protease in order to prevent viral replication in AIDS patients. The frequent and continuous mutation of HIV-1 protease gene creates a formidable obstacle for enzyme inhibition which could not be overcome by the traditional single drug therapy. Nowadays, in vitro and in silico studies of protease inhibition constitute an advanced field in biological researches. In this article, we tried to simulate protease-substrate complexes in different states; a native state and states with whiskers deleted from one and two subunits. Molecular dynamic simulations were carried out in a cubic box filled with explicit water at 37°C and in 1atomsphere of pressure. Results Our results showed that whisker truncation of protease subunits causes the dimer structure to decrease in compactness, disrupts substrate-binding site interactions and changes in flap status simultaneously. Conclusions Based on our findings we claim that whisker truncation even when applied to a single subunit, threats dimer association which probably leads to enzyme inactivation. We may postulate that inserting a gene to express truncated protease inside infected cells can interfere with protease dimerization. The resulted proteases would presumably have a combination of native and truncated subunits in their structures which exert no enzyme activities as evidenced by the present work. Our finding may create a new field of research in HIV gene therapy for protease inhibition, circumventing problems of drug resistance.