Antiviral and protective effect of small interfering RNAs against rift valley fever virus in vitro

BACKGROUND

Rift Valley Fever Virus (RVFV) is an arbovirus, a zoonotic disease that resurfaces as a potential hazard beyond geographic boundaries. Fever that can proceed to encephalitis, retinitis, hemorrhagic fever, and death is the main manifestation observed in human infections. RVFV has no authorized medication. The RNA interference (RNAi) gene silencing pathway is extremely well conserved. By targeting specific genes, small interfering RNA (siRNA) can be used to suppress viral replication. The aim of this study was to design specific siRNAs against RVFV and evaluate their prophylactic and antiviral effects on the Vero cells.

METHODS AND RESULTS

Various siRNAs were designed using different bioinformatics tools. Three unique candidates were tested against an Egyptian sheep cell culture-adapted strain BSL-2 that suppressed RVFV N mRNA expression. SiRNAs were transfected a day before RVFV infection (pre-transfection), and 1 h after the viral infection (post-transfection), and were evaluated to detect the silencing activity and gene expression decrease using real-time PCR and a TCID50 endpoint test. The degree of N protein expression was determined by western blot 48 h after viral infection. D2 which targets the (488-506 nucleotides), the middle region of RVFV N mRNA was the most effective siRNA at 30 nM concentration, it almost eliminates N mRNA expression when utilized as antiviral or preventive therapy. siRNAs had a stronger antiviral silencing impact when they were post-transfected into Vero cells.

CONCLUSION

Pre and post-transfection of siRNAs significantly reduced RVFV titer in cell lines, offering novel and potentially effective anti-RVFV epidemics and epizootics therapy.

Effect of Y3+ on the structural and photoluminescence properties of yttrium doped sodium borate glasses

Glasses of the composition 70%B₂ O₃ -(30-x)%Na₂ O-x%Y₂ O₃ with x=0, 0.5, 1, 1.5, 2 and 2.5 mole% are manufactured by the melt quenching method. X-ray diffraction test indicate the amorphous structure of the glasses, with the presence of some YBO₃ clusters in the high yttrium content samples. The FTIR analysis proved the presence of different borate groups and linkages, in addition to nonsystematic changes of the ratio BO₃ /BO₄ in the glasses. Forming ability of the glasses is found approximately stable for the low Y³⁺ content samples and increases for the heavily doped samples. Density of the samples is found to increase as the Y³⁺ concentration increases, while the molar volume decreases. The bond strength of the examined glasses suggests the covalent nature is dominant between bonds. All of the Y³⁺ doped glasses are found to emit greenish-cyan light when excited by λ ex = 365 nm . The photoluminescence intensity is shown to be enhanced by the generated YBO₃ groups. The obtained correlated color temperature values with 82.5% purity recommend the suitability of these glasses for the applications in the outdoor illumination.

Antiviral activity of Ribavirin nano-particles against measles virus

Measles virus considers an important cause of child morbidity and mortality in some areas as Africa. Ribavirin's activity as a nucleoside analog can disclose the surprisingly broad spectrum action against several RNA viruses under laboratory cell culture conditions. The Current study aimed to investigate the antiviral activity of ribavirin Nano gold particles (AuNPs) against measles virus on vero cell line. Ribavirin- AuNPs was prepared, characterization and the cytotoxicity of ribavirin, AuNPs and ribavirin -AuNPs were tested on vero cells using MTT assay. Antiviral activiry of ribavirin, AuNPs and ribavirin- AuNPswere determined on vero cells using simultaneous, pre-infection and post-infection protocols. Results indicated safety of ribavirin and ribavirin-AuNPs on vero cells, there was a reduction by 78.1% when vero cells treated with ribavirin -AuNPs at 99.5µg/ml while, the viral reduction was 25.4% when ribavirin 500 µg /ml was used for the same viral concentration. Our results concluded that ribavirin - AuNPs had a higher antiviral activity with lower dose than ribavirin alone and the maximal activity showed when it used after the virus infection.

Active and passive case detection strategies for the control of leishmaniasis in Bangladesh

SETTING

Two subdistricts in Bangladesh, Fulbaria and Trishal, which are hyperendemic for leishmaniasis.

OBJECTIVE

To determine 1) the numbers of patients diagnosed with visceral leishmaniasis (VL) and post-kala azar dermal leishmaniasis (PKDL) using an active case detection (ACD) strategy in Fulbaria and a passive case detection (PCD) strategy in Trishal, and 2) the time taken from symptoms to diagnosis in the ACD subdistrict.

DESIGN

A cross-sectional descriptive study of patients diagnosed from May 2010 to December 2011. The ACD strategy involved community education and outreach workers targeting households of index patients using symptom-based screening and rK-39 tests for suspected cases.

RESULTS

In the ACD subdistrict (Fulbaria) and PCD sub-district (Trishal), respectively 1088 and 756 residents were diagnosed with VL and 1145 and 37 with PKDL. In the ACD subdistrict, the median time to diagnosis for patients directly referred by outreach workers or self-referred was similar, at 60 days for VL and respectively 345 and 360 days for PKDL.

CONCLUSION

An ACD strategy at the subdistrict level resulted in an increased yield of VL and a much higher yield of PKDL. As PKDL acts as a reservoir for infection, a strategy of ACD and treatment can contribute to the regional elimination of leishmaniasis in the Indian sub-continent.

Cyclodextrin glucosyltransferase production by Bacillus megaterium NCR: evaluation and optimization of culture conditions using factorial design

Statistically-based experimental designs were used to optimize the production of cyclodextrin glucosyltransferase (CGTase) from a local isolate of Bacillus megaterium using shack culture fermentation. Seven cultural conditions were examined for enzyme production and specific activity using Plackett-Burman factorial design. Fermentation time and K(2)HPO(4) level were the crucial for factors improving enzyme production process. The steepest ascent design was adopted-based on the results recorded with Plackett-Burman design. Maximal enzyme estimates (activity 56.1 U/ml, and specific activity 62.7 U/mg protein) were achieved. A verification experiment was carried out to examine model validation of this optimization.

Inactivation of aflatoxin B1 in corn meal, copra meal and peanuts by chlorine gas treatment

More than 75% degradation of aflatoxin B1 (AFB1) was achieved after treatment of AFB1-spiked corn meal, spiked copra meal (the residue of the kiln-dried coconut kernels after mechanical expulsion of oil) and peanuts artificially infected with Aspergillus parasiticus, with 11, 16 and 35 mg chlorine gas per g meal or peanuts, respectively. At these chlorine gas treatment levels, extension of the exposure period of the corn meal and copra meal beyond 2.5 hr, and the peanuts beyond 1 day, did not increase the percentage degradation of AFB1. The mutagenicity of chlorine-treated copra meal and peanuts spiked with AFB1 was greatly reduced compared with untreated controls, as determined in Salmonella typhimurium strain TA98 in the presence of rat liver S-9 mix; the reduction in mutagenicity was found to be highly correlated with the reduction in AFB1 levels. Reactions of chlorine with AFB1 or constituents of the meals or peanuts did not appear to generate new mutagenic compounds. The moisture content of the meals and peanuts appeared to be an important factor affecting the degradation of AFB1 by chlorine gas.

Tolerance to long-term feeding of isolated peanut lectin in the rat: evidence for a trophic effect on the small intestines

Previously we have shown that rats fed a diet containing raw peanut meal as the sole source of protein exhibited alterations in enzyme activity and composition of certain organs. To determine the effects of isolated peanut lectin on body growth and on the intestines, experiments were carried out in weanling, male, Sprague-Dawley rats fed a casein diet incorporated with purified peanut lectin at three levels, 0.004, 0.04, and 0.2% for 23 days. Body weight gain was normal with all three diets. In rats fed the 0.004 and 0.04% peanut lectin, there were no changes in any of the small intestinal mucosal parameters under study. However, in rats consuming the 0.2% peanut lectin diet, the proximal, mid, and distal third regions of the small intestines all showed marked increases in mucosal weight, protein, and DNA contents, but without altered villus morphology. Of the 3 brush border enzymes studied, namely maltase, gamma-glutamyltranspeptidase, and alkaline phosphatase, none was altered in activity in any region, suggesting that microvillus integrity was normal. These results are similar to the reported actions of red kidney bean lectin on the intestines. We conclude that peanut lectin at up to 0.2% of the diet does not inhibit food intake or growth of weanling rats and is apparently trophic for all areas of the small intestines.

Reduction of mutagenicity and toxicity of aflatoxin B1 by chlorine gas treatment

Chlorine gas was used to treat aflatoxin B1 (AFB1). The time-related exposure study showed that 4 ml (15 mg) pure chlorine gas caused about 90% destruction of 100 micrograms AFB1 within 10 min, at standard temperature and pressure. Four fluorescent reaction products were produced, two of which were identified as 8,9-dichloro-AFB1 and 8,9-dihydroxy-AFB1 (diol). The use of [14C]AFB1 confirmed the 90% destruction of the compound by chlorine gas. An increased destruction of AFB1 also occurred when an increased amount of chlorine gas was used. The mutagenic activity of the AFB1 sample treated for 10 min was reduced to about 5% of the untreated control using the Salmonella typhimurium strain TA98 in the presence of a rat-liver S-9 mix. A similar time-related reduction in AFB1 toxicity after chlorine treatment was also achieved using the chicken embryo toxicity assay.

Destruction of Aflatoxins on Peanuts by Oven- and Microwave-Roasting 1

Effects of oven and microwave roasting on aflatoxin-contaminated peanuts were studied. In artificially contaminated peanuts, oven-roasting for 30 min at 150°C or microwave-roasting for 8.5 min at 0.7 kW were equally effective in destroying 30 to 45% of AFB₁. Analysis was performed by the Best Food method followed by thin-layer chromatography and densitospectrometry. In naturally contaminated peanuts, both oven- and microwave-roasting were equally effective in destroying 48 to 61% of AFB₁ and 32 to 40% of aflatoxin G₁ (AFG₁).

Evaluating Cheese-like Emulsions from Animal Blood Proteins and Whey Solids 1

Animal blood globin powder and blood plasma concentrate prepared from cattle blood, were incorporated, along with modified whey solids, hydrolyzed cereal solids, butter, cellulose gum and water into heat processed cheese-like emulsions. Globin protein in the emulsion ranged from 12.2 to 16.4% while the plasma protein range was from 1.8 to 6.2%. The ingredients were blended while the pH was being raised to pH 6.8 and the mixtures were processed at 116 C for 15 min. Texture profile parameters of hardness, springiness and cohesiveness were evaluated. Increased globin protein concentration decreased springiness and cohesiveness. Hardness apparently was maximal at an approximate globin/plasma protein ratio of 5:1.