Putative progressive and abortive feline leukemia virus infection outcomes in captive jaguarundis (<Emphasis Type="Italic">Puma yagouaroundi</Emphasis>)

Background

Feline leukemia virus (FeLV) is an exogenous gammaretrovirus of domestic cats (Felis catus) and some wild felids. The outcomes of FeLV infection in domestic cats vary according to host susceptibility, virus strain, and infectious challenge dose. Jaguarundis (Puma yagouaroundi) are small wild felids from South and Central America. We previously reported on FeLV infections in jaguarundis. We hypothesized here that the outcomes of FeLV infection in P. yagouaroundi mimic those observed in domestic cats. The aim of this study was to investigate the population of jaguarundis at Fundação Parque Zoológico de São Paulo for natural FeLV infection and resulting outcomes.

Methods

We investigated the jaguarundis using serological and molecular methods and monitored them for FeLV-related diseases for 5 years. We retrieved relevant biological and clinical information for the entire population of 23 jaguarundis held at zoo. Post-mortem findings from necropsies were recorded and histopathological and immunohistopathological analyses were performed. Sequencing and phylogenetic analyses were performed for FeLV-positive samples. For sample prevalence, 95% confidence intervals (CI) were calculated. Fisher’s exact test was used to compare frequencies between infected and uninfected animals. P-values <0.05 were considered significant.

Results

In total, we detected evidence of FeLV exposure in four out of 23 animals (17%; 95% CI 5–39%). No endogenous FeLV (enFeLV) sequences were detected. An intestinal B-cell lymphoma in one jaguarundi was not associated with FeLV. Two jaguarundis presented FeLV test results consistent with an abortive FeLV infection with seroconversion, and two other jaguarundis had results consistent with a progressive infection and potentially FeLV-associated clinical disorders and post-mortem changes. Phylogenetic analysis of env revealed the presence of FeLV-A, a common origin of the virus in both animals (100% identity) and the closest similarity to FeLV-FAIDS and FeLV-3281 (98.4% identity), originally isolated from cats in the USA.

Conclusions

We found evidence of progressive and abortive FeLV infection outcomes in jaguarundis, and domestic cats were probably the source of infection in these jaguarundis.

     

Octopus: a platform for the virtual high-throughput screening of a pool of compounds against a set of molecular targets

Octopus is an automated workflow management tool that is scalable for virtual high-throughput screening (vHTS). It integrates MOPAC2016, MGLTools, PyMOL, and AutoDock Vina. In contrast to other platforms, Octopus can perform docking simulations of an unlimited number of compounds into a set of molecular targets. After generating the ligands in a drawing package in the Protein Data Bank (PDB) format, Octopus can carry out geometry refinement using the semi-empirical method PM7 implemented in MOPAC2016. Docking simulations can be performed using AutoDock Vina and can utilize the Our Own Molecular Targets (OOMT) databank. Finally, the proposed software compiles the best binding energies into a standard table. Here, we describe two successful case studies that were verified by biological assay. In the first case study, the vHTS process was carried out for 22 (phenylamino)urea derivatives. The vHTS process identified a metalloprotease with the PDB code 1GKC as a molecular target for derivative LE&007. In a biological assay, compound LE&007 was found to inhibit 80% of the activity of this enzyme. In the second case study, compound Tx001 was submitted to the Octopus routine, and the results suggested that Plasmodium falciparum ATP6 (PfATP6) as a molecular target for this compound. Following an antimalarial assay, Tx001 was found to have an inhibitory concentration (IC₅₀) of 8.2 μM against PfATP6. These successful examples illustrate the utility of this software for finding appropriate molecular targets for compounds. Hits can then be identified and optimized as new antineoplastic and antimalarial drugs. Finally, Octopus has a friendly Linux-based user interface, and is available at www.drugdiscovery.com.br.

Open image in new window

Graphical Abstract Octopus: A platform for inverse virtual screening (IVS) to search new molecular targets for drugs.

     

In vitro Antiproliferative and Antibacterial Activities of Essential Oils from Four Species of Guatteria

The essential oils (EOs) extracted from four species of the genus Guatteria, G. australis, G. ferruginea, G. latifolia, and G. sellowiana were analyzed. A total of 24, 22, 25, and 19 constituents of the oils from four species, respectively, were identified by GC/MS. These oils showed qualitative and quantitative differences. All the oils contained the oxygenated sesquiterpenes spathulenol (11.04 – 40.29%) and caryophyllene oxide (7.74 – 40.13%) as predominant constituents. Evaluation of antiproliferative activity of the EOs showed strong selectivity (1.1 – 4.1 μg/ml) against the tumor cell line OVCAR‐03 (ovarian cancer), i.e., more active than the positive control doxorubicin (11.7 μg/ml). All EOs showed strong antibacterial activity (minimum inhibitory concentrations of 0.062 – 0.25 mg/ml) against strains of Rhodococcus equi.     

Environmental stress linked to consumption of maternally derived carotenoids in brown trout embryos (Salmo trutta)

The yellow, orange, or red colors of salmonid eggs are due to maternally derived carotenoids whose functions are not sufficiently understood yet. Here, we studied the significance of naturally acquired carotenoids as maternal environmental effects during embryo development in brown trout (Salmo trutta). We collected eggs from wild females, quantified their egg carotenoid content, fertilized them in vitro in full‐factorial breeding blocks to separate maternal from paternal effects, and raised 3,278 embryos singly at various stress conditions until hatching. We found significant sire effects that revealed additive genetic variance for embryo survival and hatching time. Dam effects were 5.4 times larger than these sire effects, indicating that maternal environmental effects play an important role in determining embryo stress tolerance. Of the eight pigment molecules that we targeted, only astaxanthin, zeaxanthin (that both affected egg redness), and lutein were detected above our confidence thresholds. No strong link could be observed between carotenoid content in unfertilized eggs and embryo mortality or hatching timing. However, the consumption of carotenoids during our stress treatment was negatively correlated to embryo survival among sib groups and explained about 14% of the maternal environmental variance. We conclude that maternally derived carotenoids play a role in the ability of embryos to cope with environmental stress, but that the initial susceptibility to the organic pollution was mainly determined by other factors.     

Standardization and Prevalence of the Booster Phenomenon: Evaluation Using a Two-Step Skin Test with 43 kDa Glycoprotein in Individuals from an Endemic Region of Paracoccidioidomycosis

Background

We estimated the occurrence rate of the booster phenomenon by using an intradermal test with 43 kDa glycoprotein in an endemic area of paracoccidioidomycosis in the central-west region of Brazil.

Methods

Individuals who had a negative result on a survey performed by using an intradermal test with 43 kDa glycoprotein in an endemic area of paracoccidioidomycosis underwent a second intradermal test after 10–15 days to determine the presence or absence of the booster phenomenon. Statistical analyses were performed using the Chi-square test, Chi-square for linear trend test, Student’s t test, and binomial test; p < 0.05 was considered significant.

Results

For the first time, we reported the occurrence of the booster phenomenon to an intradermal reaction caused by 43 kDa glycoprotein at a rate of 5.8–8.4%, depending on the test’s cutoff point. This suggests that a cutoff point should be considered for the booster phenomenon in intradermal tests with 43 kDa glycoprotein: a difference of 6–7 mm between readings according to the first and second tests, depending on the purpose of the evaluation.

Conclusion

The results indicate that the prevalence of paracoccidioidal infection in endemic areas is underestimated, as the booster phenomenon has not been considered in epidemiological surveys for this infection.

     

<Emphasis Type="Italic">Azospirillum</Emphasis> spp. from native forage grasses in Brazilian Pantanal floodplain: biodiversity and plant growth promotion potential

A sustainable alternative to improve yield and the nutritive value of forage is the use of plant growth-promoting bacteria (PGPB) that release nutrients, synthesize plant hormones and protect against phytopathogens (among other mechanisms). Azospirillum genus is considered an important PGPB, due to the beneficial effects observed when inoculated in several plants. The aim of this study was to evaluate the diversity of new Azospirillum isolates and select bacteria according to the plant growth promotion ability in three forage species from the Brazilian Pantanal floodplain: Axonopus purpusii, Hymenachne amplexicaulis and Mesosetum chaseae. The identification of bacterial isolates was performed using specific primers for Azospirillum in PCR reactions and partial sequencing of the 16S rRNA and nifH genes. The isolates were evaluated in vitro considering biological nitrogen fixation (BNF) and indole-3-acetic acid (IAA) production. Based on the results of BNF and IAA, selected isolates and two reference strains were tested by inoculation. At 31 days after planting the plant height, shoot dry matter, shoot protein content and root volume were evaluated. All isolates were able to fix nitrogen and produce IAA, with values ranging from 25.86 to 51.26 mg N mL^?1 and 107–1038 µmol L^?1, respectively. The inoculation of H. amplexicaulis and A. purpusii increased root volume and shoot dry matter. There were positive effects of Azospirillum inoculation on Mesosetum chaseae regarding plant height, shoot dry matter and root volume. Isolates MAY1, MAY3 and MAY12 were considered promising for subsequent inoculation studies in field conditions.     

Assessment of the natural control of Neoleucinodes elegantalis in tomato cultivation using ecological life tables

Life table studies allow for a better understanding of mortality factors against insect pests. It assesses each mortality factor and its parameters in population suppression. Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae) is one of the major pests of solanaceous crops in South America. The background information provided by life table studies might be used for developing management strategies for controlling N. elegantalis. Thus, the aim of this study was to identify and quantify the mortality factors of N. elegantalis in tomato cultivation by using life tables. The results were obtained from 64 ecological life tables. The mortality factors for eggs, larvae and pupae were due to rain, fruit drop, predation, parasitism and unviability caused by physiological disorder and diseases. The percentage of total death for eggs, larvae and pupae were 64.2%, 24.9% and 5.93%, respectively. The highest rates of mortality were caused by predation and parasitism. Thus, mortality of N. elegantalis caused by natural enemies might be used as a basis for determining which methods are better for controlling N. elegantalis while having the lowest possible impact on its natural enemies.     

Effects of CO2-driven acidification of seawater on the calcification process in the calcareous hydrozoan Millepora alcicornis (Linnaeus, 1758)

Coral Reefs - Ocean acidification is expected to intensify due to increasing levels in the partial pressure of atmospheric CO2 (pCO2). This could negatively affect major calcifying reef organisms....     

Combined effects of sea water acidification and copper exposure on the symbiont-bearing foraminifer <Emphasis Type="Italic">Amphistegina gibbosa</Emphasis>

Coral reefs are threatened by global and local stressors such as ocean acidification and trace metal contamination. Reliable early warning monitoring tools are needed to assess and monitor coral reef health. Symbiont-bearing foraminifers (Amphistegina gibbosa) were kept under ambient conditions (no sea water acidification and no copper addition) or exposed to combinations of different levels of sea water pH (8.1, 7.8, 7.5 and 7.2) and environmentally relevant concentrations of dissolved copper (measured: 1.0, 1.6, 2.3 and 3.2 µg L^?1) in a mesocosm system. After 10- and 25-d exposure, foraminifers were analyzed for holobiont Ca²⁺-ATPase activity, bleaching, growth and mortality. Enzyme activity was inhibited in foraminifers exposed to pH 7.2 and 3.2 µg L^?1 Cu for 25 d. Bleaching frequency was also higher at pH 7.2 combined with copper addition. There was no significant effect of sea water acidification and copper addition on mortality. However, test size was smaller in foraminifers exposed to copper, with a positive interactive effect of sea water acidification. These findings can be explained by the higher availability of free copper ions at lower water pH. This condition would increase Cu competition with Ca²⁺ for the binding sites on the organism, thus inhibiting Ca²⁺-ATPase activity and affecting the organism’s overall fitness. Findings reported here suggest that key processes in A. gibbosa, such as calcification and photosynthesis, are affected by the combined effect of global (sea water acidification) and local (copper contamination) stressors. Considering the experimental conditions employed (mesocosm system, possible ocean acidification scenarios, low copper concentrations, biomarkers of ecological relevance and chronic exposure), our findings support the use of foraminifera and biomarkers analyzed in the present study as reliable tools to detect and monitor the ecological impacts of multiple stressors in coral reef environments.