Biology subjects

Mendonca, R. Z.

Publications and source records attributed to Mendonca, R. Z..

5 recordsLinked to original sources

bioRxiv2022

How a tarantula can help treat infections: Avicularia juruensis theraphotoxins that also act as antimicrobials.

Short abstractConsidering that there are still many species little-studied, this work aimed to analyze the venom of the spider Avicularia juruensis searching for antimicrobial peptides. Using reverse-phase high-performance liquid chromatography, microbial growth inhibition assay, transcriptomics, and proteomics approaches we identified three antimicrobial peptides: Avilin, Juruin_2, and Juruenine. All of them showed similarities with neurotoxins that act on ion channels and, probably, they have the ICK motif. The study of animal venoms is of great importance to carry out the characterization of unknown components and that may have a biotechnological application, in special venoms from spiders that are from less studied families. Spiders are the most successful group of venomous animals, comprising more than 50,350 species distributed in all terrestrial habitats. One strategy that facility their broad distribution is the production of elaborate venoms, which are composed of inorganic salts, organic molecules with low molecular mass, free amino acids, small polypeptides, linear peptides, nucleotides, disulfide-rich peptides, enzymes, and high molecular mass proteins. Considering that there are still many species little-studied, this work aimed to analyze the venom of the mygalomorph spider Avicularia juruensis searching for new antimicrobial peptides. Using reverse-phase high-performance liquid chromatography, microbial growth inhibition assay, transcriptomics, and proteomics approaches we identified three antimicrobial peptides that were named Avilin, Juruin_2, and Juruenine. All of them showed similarities with neurotoxins that act on ion channels and, probably, they have the ICK motif in their structure. The ICK fold seems to be conserved in several venomous animal lineages and presents elevated functional diversity, as well as gives stability to the toxins. The study of animal venoms is of great importance to carry out the characterization of unknown components and that may have a biotechnological application (like the antimicrobial peptides), in special venoms from spiders that are from less studied families.

microbiology↗

bioRxiv2022

"The anti-apoptotic effect of Lonomia obliqua hemolymph is associated with the mitochondria pathway"

The apoptosis death is a very important factors in production processes that limited the industrial production of some proteins of economic interest. However, one of the forms to increase the cellular productivity would be inhibit or attenuate the cellular death. Recently we have demonstrated the presence of a potent anti-apoptotic protein in Lonomia obliqua hemolymph which extends the cell culture viability through apoptosis prevention. By the other side, has been reported that mitochondria have one important action in the apoptosis control process, being that mitochondria membrane permeabilization (MMP) can be an important stage in this process. MMP associated or not with the loss of the electrochemical potential of the mitochondria and alteration of the matrix is responsible for the inter membranes protein release (e.g. cytochrome c, the AIF, etc) of cytosol. The result obtained showed that the addition of a protein from Lonomia obliqua hemolymph in the culture lead to a prolongation of the cellular life (3-4 days) and the cells leading a high electrochemical potential of the mitochondria. This protein can has its action in mitochondria membrane, avoiding the loss of the membrane permeability and the Cytochrome-C release. As positive control, apoptosis death in these cultures was induced by 50 m of t-BHP or 600 m of H202. The presence of apoptosis was characterized by flow citometry, microscopy electronic and agarose gel electrophoresis. The potential electrochemical of the mitochondria was determined by JC-1, Hoechst 33324 and DIOC6. Cytochrome C was identified in cytosol by an anti-cytochrome antibody.

cell biology↗

bioRxiv2022

Antiviral activity of the hemolymph of Podalia sp and M. albicolis (Lepidoptera: Megalopigydae)

Potent antiviral activity against measles, influenza, picornavirus and herpes simplex viruses was observed in the hemolymph of Podalia sp and M. Albicolis (Lepidoptera: Megalopigydae). The antiviral proteins responsible for this activity were isolated by gel filtration chromatography using a gel filtration column system (Superdex 75) and further fractionated using a Resource-Q ion exchange column system. Experiments with the semi-purified protein led to a 128-fold reduction in picornavirus production, 64-fold reduction in measles virus production and a 32-fold reduction in influenza virus replication. qPCR showed a significantly lower level of herpes virus transcription. In addition no citotoxicity and genotoxicity effect was observed for Vero cells, suggesting a very interesting potential antiviral activity.

microbiology↗

bioRxiv2021

Antimicrobial activity of flavonoids glycosides and pyrrolizidine alkaloids from propolis of Scaptotrigona aff. postica.

Stingless bees belonging to the Meliponinae subfamily, are known as meliponines. Scaptotrigona affinis postica Latreille, 1807 from northeast of Brazil is popularly known as tubi in Maranhao State. Scaptotrigona, which is widely distributed in neotropical regions, includes species that build their hives in pre-existing cavities. Flavones di-C-glycosides, and the pyrrolizidine alkaloid 7-(3-methoxy-2-methylbutyryl)-9-echimidinylretronecine were reported previously in propolis from S. postica. Fractions 40 AEP and 40 MEP from ethanolic extract were analyzed by LC-MS. The chromatographic profile of fractions 40 AEP and 40 MEP revealed the presence of many pyrrolizidine alkaloids, among them, lithosenine (14), lithosenine arabinoside (19), 7-angeloyl-9-(2,3- dihydroxybutyryl) retronecine (1), 7-(2-methylbutyryl) retronecine (3), 9-sarracinoylretronecine (13) and viridinatine (8),besides the flavonoids schaftoside (15), aromadendrin-7-O-methyl ether (12), 7-methoxy-5,6,3,4,5,6-hexahydroxy-flavone-3-O-glucuronide (11), mangiferin (10) and 3-O-methyl mangiferin (17). Fractions 40 AEP and 40 MEP showed antimicrobial activity against Gram negative bacteria, including Escherichia coli D31-streptomycin resistant. Cell viability was expressed in terms of the relative absorbance of treated and untreated cells (control). There was no statistical difference between treated and untreated cells.

microbiology↗

bioRxiv2021

Evaluation of genotoxic and cytogenetic effects of saponins and aluminum hydroxide adjuvant on viral vaccine

Bovine papillomavirus (BPV) is the etiological agent of bovine papillomatosis, infectious disease characterized by the presence of benign tumors that can progress to malignancy. The phylogenetic classification of the PVs is performed based on the sequence homology of the Open Reading Frame L1, the most conserved among different viral serotypes. Given the immunogenicity of saponins, it,s has been used as a candidate as adjuvant use. For this reason, the safety of using saponin as an adjuvant has to be better determined to human or veterinary vaccine use. So, this study aimed to evaluate the mutagenic and genotoxic effect of saponins in comparison with the adjuvant widely used aluminum hydroxide using an isolated and purified L1 protein from BPV as model. In this study, genomic lesions, which after processed without repair can result in mutations, were detected by comet assay. Possible damages to genetic material caused by structural chromosomal changes (clastogenesis), as well as chromosomal losses (aneugenesis) were evaluated by the micronucleus test. Both tests were done on polychromatic erythrocytes and Vero cells. The evaluation of apoptosis and necrosis of treated Vero cells was made by Annexin V / PI staining and flow cytometry. The two vaccine products (L1 +Saponin and L1 + Aluminum Hydroxide) showed damages compatible with the positive control in the comet assay and both slightly elevated the micronucleus levels, in the Cell Viability Assay the results with Aluminum Hydroxide were satisfactory, characterizing Aluminum Hydroxide as a safer adjuvant according to the proposed tests, better than the saponins. Some fractions of the saponin extract separated by High Performance Liquid Chromatography were evaluated against genotoxic activity by comet assay, and their identities were confirmed by similarity to the reference standard by mass spectrometry.

microbiology↗