Bacillus spp. metabolites are effective in eradicating Aedes aegypti (Diptera: Culicidae) larvae with low toxicity to non-target species.

The growing spread of dengue, chikungunya and Zika viruses demand the development of new and environmentally safe control methods for their vector, the mosquito Aedes aegypti. This study aims to find novel larvicidal agents from mutualistic (endophytic and rhizospheric) or edaphic bacteria that have no action against non-target organisms. Eleven out of the 254 bacterial strains tested were able to kill Ae. aegypti larvae. Larvicidal activity did not depend on presence of cells, since culture supernatants or crude lipopeptide extracts (CLEs) killed the larvae. Bacillus safensis BacI67 and Bacillus paranthracis C21 supernatants were the best performing supernatants, displaying the lowest lethal concentrations (LC50 = 31.11 µL/mL and 45.84 µL/mL, respectively). Bacillus velezensis B64a and Bacillus velezensis B15 produced the best performing CLEs (LC50 = 0.11 mg/mL and 0.12 mg/mL, respectively). Mass spectrometry analysis of CLEs detected a mixture of surfactins, iturins, and fengycins. The samples tested were weakly- or non-toxic to mammalian cells (RAW 264.7 macrophages and VERO cells) and non-target organisms (Caenorhabditis elegans, Galleria mellonella, Scenedesmus obliquus, and Tetrahymena pyriformis) - especially B. velezensis B15 CLE. The biosynthetic gene clusters related to secondary metabolism identified by whole genome sequencing of the four best performing bacteria strains revealed clusters for bacteriocin, beta-lactone, lanthipeptide, non-ribosomal peptide synthetases, polyketide synthases (PKS), siderophores, T3PKS, type 1 PKS-like, terpenes, thiopeptides, and trans-AT-PKS. Purification of lipopeptides may clarify the mechanisms by which these extracts kill Ae. aegypti larvae.

Latent bovine herpesvirus 1 and 5 in milk from naturally infected dairy cattle.

Bovine herpesvirus 1 and 5 (BoHV-1 and -5) are antigenically and genetically related and can establish latent infection. We aimed to analyze the applicability of the milk sample to detect latently BoHV-infected cattle. BoHV-1 non-vaccinated clinically healthy cows from five dairy cattle herds (herd 1, n=24; herd 2, n=39; herd 3, n=39; herd 4, n=36; herd 5, n=70) were studied. We confirmed the presence of BoHV-1, and for the first time, BoHV-5 in the milk of naturally infected dairy cattle.

Evaluation of the antiviral activities of Bacharis dracunculifolia and quercetin on Equid herpesvirus 1 in a murine model.

Equid herpesvirus 1 (EHV-1) is a pathogen of high economic importance in equine breeding operations around the world. EHV-1 infection causes respiratory, neurologic and reproductive disease. The absence of an efficient therapy has caught the attention of the scientific community and the therapeutic activities of natural products with its antivirals effects might be effective for the disease's treatment. Herein it was evaluated the prophylactic and therapeutic potential of quercetin and ethanolic extracts of Bacharis dracunculifolia formulations compared to Penciclovir® in an in vivo EHV-1 infection model. Six to seven-week-old female C57BL/6 mice were randomly organized into fifteen groups with six animals each. Ex-1 represents the treatment post-challenge groups to assess morbidity, mortality and weight variation. Ex-2 represents the animals that received treatment for 5 days post-challenge for lesion evaluation. In Ex-3 animals were treated prior to viral challenge to assess morbidity, mortality and weight variation. All mice in the treatment groups were challenged by intranasal inoculation of 3.0 × 105 TCID50 EHV-1. The quercetin and B. dracunculifolia treatment decreased morbimortality in post-challenge treatment (Ex-1) and EHV-1 related lesions (Ex-2). Treatment prior to viral challenge (Ex-3) did not show any significant results. Based on the results of the present study, both tested formulations are promising antiviral agents for the treatment of EHV-1 infection.

Genotoxic studies in hypertensive and normotensive rats treated with amiodarone.

Amiodarone, a benzofuran derivative, is a very effective antiarrhythmic medication, but has potential to cause side effects. Although its cytotoxicity potential is very well-known, there are few reports about its genotoxicity effects. Since amiodarone has not been investigated in genotoxicity studies, and the spontaneously hypertensive rat (SHR) is a well-characterized model for hypertension, the aim of the present study was to perform cytogenetic analysis on chromosome aberrations in bone marrow cells of SHRs and normotensive Wistar-Kyoto rats (WKYs) that received oral amiodarone treatment for 4 weeks. Amiodarone activity was also monitored using electrocardiograms. The presence of bradycardia in amiodarone-treated rats confirmed that this drug was really active. Metaphase analysis on bone marrow cells showed that there were significant differences in total chromosomal damage and percentage abnormal metaphase between WKY and SHR negative controls. In the SHR negative control, the frequencies of basal chromosomal aberrations and abnormal metaphases were significantly higher (p<0.05). There were high numbers of chromosomal aberrations in all amiodarone-treated groups, compared with negative controls. In amiodarone-treated groups, the most frequent chromosomal aberration was chromatid breaks. More chromosomal aberrations were found in WKYs that received amiodarone, with a statistically significant difference in comparison with negative controls (p<0.05). However, in SHR rats there was no significant difference between the amiodarone and negative groups regarding chromosomal damage induction. These results showed that treatment with amiodarone was genotoxic in WKYs, but not in SHRs. Further studies are needed to confirm whether amiodarone is genotoxic or efficient and harmless, among humans undergoing therapy.