Abstract in English:

ABSTRACT The horizontal transmission of the entomopathogenic fungus Beauveria bassiana Unioeste 76 strain among adults of Euschistus heros was evaluated in the laboratory and greenhouse using sporulated cadavers and live insects contaminated as a source of inoculate. Adult insects in the laboratory bioassay either received treatments with dry conidia or were sprayed with an oily dispersion formulation, and the treatments were comprised of 10, 30, or 50% of contaminated insects. For the greenhouse bioassay, nylon cages were prepared, with soybean plants grown in pots. A total of 20 healthy brown stink bugs were released along with one or three sporulated cadavers of brown stink bugs, attached to the plant stem. In the bioassay with live insects, 20 stink bugs were released, and the treatments were comprised of 10, 30, or 50% contaminated insects (2:18, 6:14, and 10:10, fungus-treated insects : healthy insects). In all experiments, the control group was comprised only of healthy insects. Dead stink bugs were daily disinfested and transferred to a wet chamber for confirmation of death by fungus. Confirmed mortality was observed, which shows the occurrence of horizontal transmission. Mortality was higher when more contaminated insects were used in the population, in most treatments. The occurrence of transmission in the laboratory and the greenhouse emphasizes the potential of the Unioeste 76 strain as mortality agent and as an agent for maintaining the inoculum potential for the brown stink bug.

Abstract in English:

ABSTRACT The brown stink bug, Euschistus heros, is considered one of the main pests in Brazil, causing significant damage to several crops. Currently, the principal method of control involves the excessive use of insecticides, leading to the development of resistant populations and environmental contamination. Therefore, it becomes crucial to explore more sustainable control alternatives, with biological agents, particularly entomopathogenic bacteria, emerging as promising due to their proven toxic activity against various insect and insect families. Thus, this study aimed to explore the potential of entomopathogenic bacteria in the control of E. heros. The initial screening of 125 bacteria identified 19 efficient strains, which were tested at 10% concentration under laboratory conditions. Molecular identification was conducted by polymerase chain reaction amplification of the 16S, gyrB, and rpoD genes, followed by sequencing and comparison in EzBioCloud 16S and GenBank. Additionally, the survival rate of E. heros was evaluated at bacterial concentrations of 10, 20, 40, 80, and 100%. Among the isolates tested at 10% concentration, strains 292B3, 457C4, 365BNP6, 742D, 427B, 321B, and Photorhabdus luminescens emerged as the most virulent. Molecular analysis of these strains revealed high similarity to the species Serratia marcescens, Bacillus toyonensis, and Bacillus cereus. The survival rates of E. heros suggested that control efficiency is not solely linked to bacterial concentration, but it also depends on the mechanisms of action and the ability to colonize and interact with the pest.

Abstract in English:

ABSTRACT The mite Allopsoroptoides galli has been described as a psoroptoidid belonging to the subfamily Psoroptidae. This feather mite was first found in the year 2010, parasitizing hens on an egg farm in the state of São Paulo, Brazil. A phylogenetic investigation on the first DNA sequences of the mite A. galli was conducted. Through the polymerase chain reaction technique, fragments of the 18S and 28S rRNA region were amplified and then sequenced using the Sanger method. The sequences obtained were deposited in GenBank (OK533677 and OK533676). The identity of the amplified DNA fragments was established by entering the sequences obtained into the BLAST software. Listed sequences from GenBank, from both the 18S and the 28S region, were retrieved and aligned to subsequently set up phylogenetic trees, by means of the neighbor-joining (NJ), maximum parsimony (MP), and maximum likelihood (ML) methods. For both sequences obtained experimentally, the search in the GenBank DNA database yielded high similarity only with sequences of the pyroglyphid mite Dermatophagoides farinae. All the phylogenetic trees obtained for 18S rRNA sequences and 28S rRNA sequences presented a high degree of discordance with the current taxonomy.

Abstract in English:

ABSTRACT Respiratory tract infections in poultry have become serious problems with negative consequences for poultry production. Among these diseases, mycoplasmosis and avian pneumoviruses stand out, which, despite being relevant in poultry health, have not been systematically investigated in Brazil, especially regarding the interaction between these agents or the occurrence of co-infection in broiler chickens. The present study investigated the occurrence of infection by Mycoplasma gallisepticum (MG) and subtypes A and B of avian metapneumovirus (aMPV) in broiler chickens from commercial poultry flocks kept on farms with high biosecurity standards and located in the Southeast and Midwest regions of Brazil. Polymerase chain reaction (PCR) and reverse transcription nested-PCR techniques were applied to detect and/or identify, respectively, MG and aMPV in samples of nasal and tracheal swabs collected between 2017 and 2018, from 87 batches of broiler chickens from 15 commercial production farms that showed respiratory clinical signs. Two out of 87 batches sampled (2.3%) were positive for MG, while none of them were positive for aMPV. The low or no incidence of these pathogens can be explained by the adoption of increasingly effective health control measures for these agents on farms with high biosecurity standards. In addition, there are clues that other bacterial and viral infectious agents may be involved in the etiology of respiratory problems of these broiler chickens, which showed clinical signs of respiratory diseases upon sample collection.

Abstract in English:

ABSTRACT Vesicular stomatitis virus is the causative agent of the vesicular stomatitis disease, which mainly affects cattle, swine, and horses causing significant economic losses. Many other animal species, including humans, can be also affected by the disease. Up to now, the epidemiology of vesicular stomatitis disease is not well understood. Previous epidemiological studies in Central America described the existence of an association between the presence of vesicular stomatitis New Jersey virus antibodies and environmental risk factors such as mean annual rainfall, temperature, and elevation. Additionally, molecular epidemiology studies revealed that the phylogenetic relationship between vesicular stomatitis New Jersey virus isolates is more related to ecological factors than temporal factors. We have performed a genetic analysis of vesicular stomatitis virus samples isolated from animals in different geographical regions in Venezuela. We sequenced the hypervariable region of the phosphoprotein gene of 51 samples collected over eight years. The virus was found in a wide range of environmental conditions, at high and low altitudes and with variable levels of precipitation and temperatures. In contrast with previous reports, our phylogenetic analysis showed that viruses from different ecological regions did not present significant genetic differences.

Abstract in English:

ABSTRACT Zebrafish, also known as ‘peixe-zebra’ and ‘Paulistinha’ in Brazil, have been increasingly used for studies in various areas of Medicine and Biology. This fish has several characteristics that make it more suitable for scientific experimentation than other animal models, such as a large number of embryos per mating (about 100 to 200 eggs), a short life cycle (about 2 years), development fast (60 to 90 days to have all organs and systems fully mature), sequenced genome, easy adult breeding, low maintenance cost, transparent eggs and embryos, making it possible to monitor their development. In this qualitative review we discuss the advantages and disadvantages of using the zebrafish model (Danio rerio) in the embryo and adult life stages, considering the principle of the 3 R’s (reduction, replacement and refinement) which are the basis of Bioethics applied to Animal Science Laboratory.