Recent HIV infection and annualized HIV incidence rates among sexual and gender minorities in Brazil and Peru (ImPrEP seroincidence study): a cross-sectional, multicenter study.

Background: HIV incidence estimation is critical for monitoring the HIV epidemic dynamics and the effectiveness of public health prevention interventions. We aimed to identify sexual and gender minorities (SGM) with recent HIV infections, factors associated with recent HIV infection, and to estimate annualised HIV incidence rates. Methods: Cross-sectional multicentre study in HIV testing services in Brazil and Peru (15 cities). Inclusion criteria: 18+ years, SGM assigned male at birth, not using pre-/post-exposure prophylaxis. We identified recent HIV infection using the Maxim HIV-1 LAg-Avidity EIA assay as part of a recent infection testing algorithm (RITA). Annualized HIV incidence was calculated using the UNAIDS/WHO incidence estimator tool. Multivariable logistic regression models were used to estimate factors associated with recent HIV infection. Trial registration: NCT05674682. Findings: From 31-Jan-2021 to 29-May-2022, 6899 individuals participated [Brazil: 4586 (66.5%); Peru: 2313 (33.5%)]; 5946 (86.2%) cisgender men, 751 (10.9%) transgender women and 202 (2.9%) non-binary/gender diverse. Median age was 27 (IQR: 23-34) years. HIV prevalence was 11.4% (N = 784/6899); 137 (2.0%) SGM were identified with recent HIV infection. The overall annualized HIV incidence rate was 3.88% (95% CI: 2.86-4.87); Brazil: 2.62% (95% CI: 1.78-3.43); Peru: 6.69% (95% CI: 4.62-8.69). Participants aged 18-24 years had higher odds of recent HIV infection compared to those aged 30+ years in both countries. Interpretation: Our results highlight the significant burden of HIV epidemic among SGM in large urban centres of Brazil and Peru. Public health policies and interventions to increase access to effective HIV prevention methods such as PrEP are urgently needed in Latin America. Funding: Unitaid, WHO (Switzerland), Ministry of Health from Brazil and Peru.

Same-day initiation of oral pre-exposure prophylaxis among gay, bisexual, and other cisgender men who have sex with men and transgender women in Brazil, Mexico, and Peru (ImPrEP): a prospective, single-arm, open-label, multicentre implementation study.

BACKGROUND: Although gay, bisexual, and other cisgender men who have sex with men (MSM) and transgender women have the highest HIV burden in Latin America, pre-exposure prophylaxis (PrEP) implementation is poor. We aimed to assess the feasibility of same-day oral PrEP delivery in Brazil, Mexico, and Peru. METHODS: Implementation PrEP (ImPrEP) was a prospective, single-arm, open-label, multicentre PrEP implementation study conducted in Brazil (14 sites), Mexico (four sites), and Peru (ten sites). MSM and transgender women were eligible to participate if they were aged 18 years or older, HIV-negative, and reported one or more prespecified criteria. Enrolled participants received same-day initiation of daily oral PrEP (tenofovir disoproxil fumarate [300 mg] coformulated with emtricitabine [200 mg]). Follow-up visits were scheduled at week 4 and quarterly thereafter. We used logistic regression models to identify factors associated with early loss to follow-up (not returning after enrolment), PrEP adherence (medication possession ratio ≥0·6), and long-term PrEP engagement (attending three or more visits within 52 weeks). This study is registered at the Brazilian Registry of Clinical Trials, U1111-1217-6021. FINDINGS: From Feb 6, 2018, to June 30, 2021, 9979 participants were screened and 9509 were enrolled (Brazil n=3928, Mexico n=3288, and Peru n=2293). 543 (5·7%) participants were transgender women, 8966 (94·3%) were cisgender men, and 2481 (26·1%) were aged 18-24 years. There were 12 185·25 person-years of follow-up. 795 (8·4%) of 9509 participants had early loss to follow-up, 6477 (68·1%) of 9509 were adherent to PrEP, and 5783 (70·3%) of 8225 had long-term PrEP engagement. Transgender women (adjusted odds ratio 1·60, 95% CI 1·20-2·14), participants aged 18-24 years (1·80, 1·49-2·18), and participants with primary education (2·18, 1·29-3·68) had increased odds of early loss to follow-up. Transgender women (0·56, 0·46-0·70), participants aged 18-24 years (0·52, 0·46-0·58), and those with primary education (0·60, 0·40-0·91) had lower odds of PrEP adherence. Transgender women (0·56, 0·45-0·71), participants aged 18-24 years (0·56, 0·49-0·64), and those with secondary education (0·74, 0·68-0·86) had lower odds of long-term PrEP engagement. HIV incidence was 0·85 per 100 person-years (95% CI 0·70-1·03) and was higher for transgender women, participants from Peru, those aged 18-24 years, Black and mixed-race participants, and participants who were non-adherent to PrEP. INTERPRETATION: Same-day oral PrEP is feasible for MSM and transgender women in Latin America. Social and structural determinants of HIV vulnerability need to be addressed to fully achieve the benefits of PrEP. FUNDING: Unitaid, WHO, and Ministries of Health in Brazil, Mexico, and Peru. TRANSLATIONS: For the Portuguese and Spanish translations of the abstract see Supplementary Materials section.

Resonance Raman enhancement by the intralayer and interlayer electron-phonon processes in twisted bilayer graphene.

Twisted bilayer graphene is a fascinating system due to the possibility of tuning the electronic and optical properties by controlling the twisting angle [Formula: see text] between the layers. The coupling between the Dirac cones of the two graphene layers gives rise to van Hove singularities (vHs) in the density of electronic states, whose energies vary with [Formula: see text]. Raman spectroscopy is a fundamental tool to study twisted bilayer graphene (TBG) systems since the Raman response is hugely enhanced when the photons are in resonance with transition between vHs and new peaks appear in the Raman spectra due to phonons within the interior of the Brillouin zone of graphene that are activated by the Moiré superlattice. It was recently shown that these new peaks can be activated by the intralayer and the interlayer electron-phonon processes. In this work we study how each one of these processes enhances the intensities of the peaks coming from the acoustic and optical phonon branches of graphene. Resonance Raman measurements, performed in many different TBG samples with [Formula: see text] between [Formula: see text] and [Formula: see text] and using several different laser excitation energies in the near-infrared (NIR) and visible ranges (1.39-2.71 eV), reveal the distinct enhancement of the different phonons of graphene by the intralayer and interlayer processes. Experimental results are nicely explained by theoretical calculations of the double-resonance Raman intensity in graphene by imposing the momentum conservation rules for the intralayer and the interlayer electron-phonon resonant conditions in TBGs. Our results show that the resonant enhancement of the Raman response in all cases is affected by the quantum interference effect and the symmetry requirements of the double resonance Raman process in graphene.

Melanoma Awareness Among Medical Students.

Melanoma is the most aggressive skin cancer. Since diagnosis is visual, it is critical to evaluate if students acquire enough knowledge for early detection during medical school. To assess the melanoma knowledge of first-year (freshman) and sixth-year (senior) medical students, in a Brazilian Institution. It was a transversal and quantitative study. A questionnaire with sociodemographic data, knowledge about melanoma, and the habit of skin self-exam was filled out by medical students. A total of 128 first-year and 122 seniors students were included. All the sixth-year students knew melanoma as a skin cancer compared with 46.09% of the first-year students. Melanoma clinical characteristics were known by 30.51% of the freshman and 97.54% of seniors. However, they did not know the most usual site of melanoma occurrence (79.66% of first-year students and 24.59% of senior). About the skin self-exam, only 50% of first-year students and 53.28% of senior had the habit of doing it sometimes. Medical school was effective in providing knowledge about melanoma and its features. However, this was not reflected in an increase in the number of students that did the skin self-exam, which indicates the need for new approaches in teaching.

Intralayer and interlayer electron-phonon interactions in twisted graphene heterostructures.

The understanding of interactions between electrons and phonons in atomically thin heterostructures is crucial for the engineering of novel two-dimensional devices. Electron-phonon (el-ph) interactions in layered materials can occur involving electrons in the same layer or in different layers. Here we report on the possibility of distinguishing intralayer and interlayer el-ph interactions in samples of twisted bilayer graphene and of probing the intralayer process in graphene/h-BN by using Raman spectroscopy. In the intralayer process, the el-ph scattering occurs in a single graphene layer and the other layer (graphene or h-BN) imposes a periodic potential that backscatters the excited electron, whereas for the interlayer process the el-ph scattering occurs between states in the Dirac cones of adjacent graphene layers. Our methodology of using Raman spectroscopy to probe different types of el-ph interactions can be extended to study any kind of graphene-based heterostructure.

Edge phonons in black phosphorus.

Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements.

Survival and preference of cotton boll weevil adults for alternative food sources / Sobrevivência e preferência para exploração de recursos de adultos do bicudo do algodoeiro

Abstract Plants that have potential as alternative food source (floral nectar, pollen and plant tissues) to the boll weevil during the intercropping season were evaluated considering the prevalent conditions of Cerrado in the Central Brazil. Initially, we tested the nutritional adequacy for the survival of the insect of flower resource (pollen and nectar) provided by eight plant species (fennel, mexican sunflower, castor bean, okra, hibiscus, sorghum, pigeonpea and sunn hemp). Subsequently, we tested if the resources provided by the selected plants continued to be exploited by the boll weevil in the presence of cotton plant, its main food source average longevity of boll weevil adults was significantly longer when they were fed on hibiscus’ flowers (166.6 ± 74.4) and okra flowers (34.7 ± 28.9) than when they fed on flowers of other six species. Subsequently, the preference of the boll weevil in the use of resources was compared between okra or hibiscus and cotton plants, in dual choice experiments. Boll weevils preferred plants of the three species in the reproductive stages than those in vegetative stages. Although the cotton plant in the reproductive stage was the most preferred plant of all, boll weevils preferred flowering okra and hibiscus than cotton at the vegetative stage.

Resumo Plantas que podem ser uma fonte potencial de recursos alimentares (néctar floral, pólen e tecidos vegetais) para o bicudo do algodoeiro durante a entressafra foram avaliadas, considerando as condições ambientais prevalentes na região de Cerrado do Brasil Central. Primeiro, testamos a adequação nutricional dos recursos (pólen e néctar) fornecidos por oito espécies de plantas (erva-doce, margaridão, mamona, quiabo, hibisco, sorgo, feijão guandu e crotalária) como único recurso alimentar para a sobrevivência do inseto. Posteriormente, nós avaliamos se os recursos fornecidos pelas plantas selecionadas continuaram a serem explorados pelo bicudo na presença do algodoeiro, seu recurso alimentar principal. A longevidade média do bicudo do algodoeiro foi significativamente maior quando eles foram alimentados com flores de hibisco (166,6 ± 74,4) e quiabo (34,7 ± 28,9) do que quando alimentados com flores das outras seis espécies. Em seguida, a preferência do bicudo no uso de recursos foi comparada contrastando o quiabo e o hibisco com o algodão, em experimentos de dupla escolha. Os bicudos preferiram as plantas das três espécies na fase reprodutiva em relação àquelas em estádios vegetativos. Embora a preferência por plantas de algodão na fase reprodutiva tenha sido maior, os bicudos preferiram plantas em floração de quiabo e hibisco quando estas foram contrastadas com o algodão na fase vegetativa.

Survival and preference of cotton boll weevil adults for alternative food sources / Sobrevivência e preferência para exploração de recursos de adultos do bicudo do algodoeiro

Abstract Plants that have potential as alternative food source (floral nectar, pollen and plant tissues) to the boll weevil during the intercropping season were evaluated considering the prevalent conditions of Cerrado in the Central Brazil. Initially, we tested the nutritional adequacy for the survival of the insect of flower resource (pollen and nectar) provided by eight plant species (fennel, mexican sunflower, castor bean, okra, hibiscus, sorghum, pigeonpea and sunn hemp). Subsequently, we tested if the resources provided by the selected plants continued to be exploited by the boll weevil in the presence of cotton plant, its main food source average longevity of boll weevil adults was significantly longer when they were fed on hibiscus flowers (166.6 ± 74.4) and okra flowers (34.7 ± 28.9) than when they fed on flowers of other six species. Subsequently, the preference of the boll weevil in the use of resources was compared between okra or hibiscus and cotton plants, in dual choice experiments. Boll weevils preferred plants of the three species in the reproductive stages than those in vegetative stages. Although the cotton plant in the reproductive stage was the most preferred plant of all, boll weevils preferred flowering okra and hibiscus than cotton at the vegetative stage.(AU)

Resumo Plantas que podem ser uma fonte potencial de recursos alimentares (néctar floral, pólen e tecidos vegetais) para o bicudo do algodoeiro durante a entressafra foram avaliadas, considerando as condições ambientais prevalentes na região de Cerrado do Brasil Central. Primeiro, testamos a adequação nutricional dos recursos (pólen e néctar) fornecidos por oito espécies de plantas (erva-doce, margaridão, mamona, quiabo, hibisco, sorgo, feijão guandu e crotalária) como único recurso alimentar para a sobrevivência do inseto. Posteriormente, nós avaliamos se os recursos fornecidos pelas plantas selecionadas continuaram a serem explorados pelo bicudo na presença do algodoeiro, seu recurso alimentar principal. A longevidade média do bicudo do algodoeiro foi significativamente maior quando eles foram alimentados com flores de hibisco (166,6 ± 74,4) e quiabo (34,7 ± 28,9) do que quando alimentados com flores das outras seis espécies. Em seguida, a preferência do bicudo no uso de recursos foi comparada contrastando o quiabo e o hibisco com o algodão, em experimentos de dupla escolha. Os bicudos preferiram as plantas das três espécies na fase reprodutiva em relação àquelas em estádios vegetativos. Embora a preferência por plantas de algodão na fase reprodutiva tenha sido maior, os bicudos preferiram plantas em floração de quiabo e hibisco quando estas foram contrastadas com o algodão na fase vegetativa.(AU)

Survival and preference of cotton boll weevil adults for alternative food sources.

Plants that have potential as alternative food source (floral nectar, pollen and plant tissues) to the boll weevil during the intercropping season were evaluated considering the prevalent conditions of Cerrado in the Central Brazil. Initially, we tested the nutritional adequacy for the survival of the insect of flower resource (pollen and nectar) provided by eight plant species (fennel, mexican sunflower, castor bean, okra, hibiscus, sorghum, pigeonpea and sunn hemp). Subsequently, we tested if the resources provided by the selected plants continued to be exploited by the boll weevil in the presence of cotton plant, its main food source average longevity of boll weevil adults was significantly longer when they were fed on hibiscus' flowers (166.6 ± 74.4) and okra flowers (34.7 ± 28.9) than when they fed on flowers of other six species. Subsequently, the preference of the boll weevil in the use of resources was compared between okra or hibiscus and cotton plants, in dual choice experiments. Boll weevils preferred plants of the three species in the reproductive stages than those in vegetative stages. Although the cotton plant in the reproductive stage was the most preferred plant of all, boll weevils preferred flowering okra and hibiscus than cotton at the vegetative stage.

Atypical Exciton-Phonon Interactions in WS2 and WSe2 Monolayers Revealed by Resonance Raman Spectroscopy.

Resonant Raman spectroscopy is a powerful tool for providing information about excitons and exciton-phonon coupling in two-dimensional materials. We present here resonant Raman experiments of single-layered WS2 and WSe2 using more than 25 laser lines. The Raman excitation profiles of both materials show unexpected differences. All Raman features of WS2 monolayers are enhanced by the first-optical excitations (with an asymmetric response for the spin-orbit related XA and XB excitons), whereas Raman bands of WSe2 are not enhanced at XA/B energies. Such an intriguing phenomenon is addressed by DFT calculations and by solving the Bethe-Salpeter equation. These two materials are very similar. They prefer the same crystal arrangement, and their electronic structure is akin, with comparable spin-orbit coupling. However, we reveal that WS2 and WSe2 exhibit quite different exciton-phonon interactions. In this sense, we demonstrate that the interaction between XC and XA excitons with phonons explains the different Raman responses of WS2 and WSe2, and the absence of Raman enhancement for the WSe2 modes at XA/B energies. These results reveal unusual exciton-phonon interactions and open new avenues for understanding the two-dimensional materials physics, where weak interactions play a key role coupling different degrees of freedom (spin, optic, and electronic).

Survival and preference of cotton boll weevil adults for alternative food sources

Abstract Plants that have potential as alternative food source (floral nectar, pollen and plant tissues) to the boll weevil during the intercropping season were evaluated considering the prevalent conditions of Cerrado in the Central Brazil. Initially, we tested the nutritional adequacy for the survival of the insect of flower resource (pollen and nectar) provided by eight plant species (fennel, mexican sunflower, castor bean, okra, hibiscus, sorghum, pigeonpea and sunn hemp). Subsequently, we tested if the resources provided by the selected plants continued to be exploited by the boll weevil in the presence of cotton plant, its main food source average longevity of boll weevil adults was significantly longer when they were fed on hibiscus flowers (166.6 ± 74.4) and okra flowers (34.7 ± 28.9) than when they fed on flowers of other six species. Subsequently, the preference of the boll weevil in the use of resources was compared between okra or hibiscus and cotton plants, in dual choice experiments. Boll weevils preferred plants of the three species in the reproductive stages than those in vegetative stages. Although the cotton plant in the reproductive stage was the most preferred plant of all, boll weevils preferred flowering okra and hibiscus than cotton at the vegetative stage.

Resumo Plantas que podem ser uma fonte potencial de recursos alimentares (néctar floral, pólen e tecidos vegetais) para o bicudo do algodoeiro durante a entressafra foram avaliadas, considerando as condições ambientais prevalentes na região de Cerrado do Brasil Central. Primeiro, testamos a adequação nutricional dos recursos (pólen e néctar) fornecidos por oito espécies de plantas (erva-doce, margaridão, mamona, quiabo, hibisco, sorgo, feijão guandu e crotalária) como único recurso alimentar para a sobrevivência do inseto. Posteriormente, nós avaliamos se os recursos fornecidos pelas plantas selecionadas continuaram a serem explorados pelo bicudo na presença do algodoeiro, seu recurso alimentar principal. A longevidade média do bicudo do algodoeiro foi significativamente maior quando eles foram alimentados com flores de hibisco (166,6 ± 74,4) e quiabo (34,7 ± 28,9) do que quando alimentados com flores das outras seis espécies. Em seguida, a preferência do bicudo no uso de recursos foi comparada contrastando o quiabo e o hibisco com o algodão, em experimentos de dupla escolha. Os bicudos preferiram as plantas das três espécies na fase reprodutiva em relação àquelas em estádios vegetativos. Embora a preferência por plantas de algodão na fase reprodutiva tenha sido maior, os bicudos preferiram plantas em floração de quiabo e hibisco quando estas foram contrastadas com o algodão na fase vegetativa.

Population genetic structure of Attalea vitrivir Zona (Arecaceae) in fragmented areas of southeast Brazil.

Attalea vitrivir Zona (synonym Orbignya oleifera) is one of the six species of Arecaceae known as "babassu". This species is used to make cosmetics, food, and detergents due to the high concentration of oil in the seeds. It is found only in fragmented areas of southern Bahia State and northern Minas Gerais State, southeast Brazil, and this fragmentation has affected both its ecological and genetic characteristics. We evaluated the genetic diversity and population genetic structure of A. vitrivir in six areas of two different regions at the extremes of its geographical range, in order to gain a better understanding of the factors that affect the distribution and partitioning of its diversity. Nine inter simple sequence repeat (ISSR) markers amplified 74 polymorphic bands, resulting in large diversity values (Shannon diversity index, 0.37-0.47; intrapopulation genetic diversity, 0.25-0.34). Analysis of molecular variance (AMOVA) revealed considerable differentiation between sampling sites (30.03%) and regions (12.08%), although most of the diversity was observed within sampling sites (69%). Further differentiation between sampling sites was noted more in the northern region than in the southern region, highlighting the genetic connectivity between the sampling sites within Rio Pandeiros Environmental Protection Area (southern region). The identification of two distinct genetic clusters (K = 2) corresponded to the northern and southern regions, and corroborated the AMOVA results. We suggest that the northern area, outside Rio Pandeiros Environmental Protection Area, must be included in future management plans for this species.

Relaxin affects cell organization and early and late stages of spermatogenesis in a coculture of rat testicular cells.

Relaxin and its receptor RXFP1 are co-expressed in Sertoli cells, and relaxin can stimulate proliferation of Sertoli cells. In this study, we investigated a role of relaxin in spermatogenesis, using a short-term culture of testicular cells of the rat that allowed differentiation of spermatogonia to spermatids. Sertoli, germ, and peritubular myoid cells were the predominant cell types in the culture. Sertoli and germ cells expressed RXFP1. Cultures were incubated without (control) or with 0.5% fetal bovine serum (FBS) or 100 ng/mL H2 relaxin (RLN) for 2 days. Cell organization, number, and differentiation were analyzed after 2 (D2), 5 (D5) or 8 (D8) days of culturing. Although the proportion of germ cells decayed from D2 to D5, the relative contribution of HC, 1C, 2C, and 4C germ cell populations remained constant in the control group during the whole culture. RLN did not affect the proportion of germ cell populations compared with control, but increased gene and/or protein expression of the undifferentiated and differentiated spermatogonia markers PLZF and c-KIT, and of the post-meiotic marker Odf2 in D5. RLN favored organization of cells in tubule-like structures, the arrangement of myoid cells around the tubules, arrangement of c-KIT-positive spermatogonia at the basal region of the tubules, and expression of the cell junction protein ß-catenin close to the plasma membrane region. Knockdown of relaxin with small interfering RNA (siRNA) reduced expression of ß-catenin at the cell junctions, and shifted its expression to the nucleus. We propose that relaxin may affect spermatogenesis by modulating spermatogonial self renewal and favoring cell contact.

Leaf beetle (Chrysomelidae: Coleoptera) assemblages in a mosaic of natural and altered areas in the Brazilian cerrado.

In landscape mosaics, species may use different vegetation types or be restricted to a single vegetation type or land-use feature highlighting the importance of the interaction of species requirements and environmental heterogeneity. In these systems, the determination of the overall pattern of ß-diversity can indicate the importance of the environmental heterogeneity on diversity patterns. Here, we evaluate leaf beetles (Coleoptera: Chrysomelidae) as habitat quality bioindicators in a system with varying intensities of human impacts and different phyto-physiognomies (from open field to forests). We collected 1117 leaf beetles belonging to 245 species, of which 12 species and 5 genus were considered possible bioindicators based on IndVal measures. Higher species richness was observed in forests and regenerating fields, and habitats with lower species richness included pastures, mines, and veredas. Natural fields, regenerating fields, natural cerrado, and forest had higher values of ß-diversity. Bioindicator systems that include not only species richness and abundance but also assemblage composition are needed to allow for a better understanding of Chrysomelidae response to environmental disturbance.

Effect of ractopamine on the chemical and physical characteristics of pacu(Piaractus mesopotamicus) steaks / Efeito da ractopamina sobre as características físicas e químicas de filés de pacu (Piaractus mesopotamicus)

The objective was to evaluate the use of ractopamine (RAC) in the diet for pacu (Piaractus mesopotaminus) in the finishing phase on some quality parameters of the fillets. Thirty-five animals weighing 0.868±0.168kg were distributed in a completely randomised design with five treatments (0.0 - control; 11.25, 22.50, 33.75 and 45 ppm of RAC) and seven replicates with two fillets obtained from the same animal. The diets were isocaloric and isoprotein and experimental time was 90 days. RAC did not affect (P>0.05) the initial pH or ph after 24 hours of the fillets. Compared to the control, RAC increased (P<0.05) the moisture content of the fillets in natura and lipid oxidation of samples stored for 12 days in the refrigerator or freezer for 60 days. The RAC in 11.25 ppm reduced (P<0.05) the lipid content, while 45 ppm reduced (P<0.05) the crude protein in the fillets. Considering only RAC, there was a linear increase (P<0.05) in the lipid content (P<0.05) and a linear reduction in crude protein and weight loss after cooking the fillets. There was a quadratic effect (P<0.05) on the ash content, weight loss and lipid oxidation in fillets stored in the refrigerator or freezer. A RAC dose of 33.75 ppm resulted in a lower lipid oxidation index. In conclusion, ractopamine at 11.25 ppm is effective for reducing the fat content in fillets of pacu, although it increases the formation of peroxides in samples kept in the freezer for longer than 60 days. At 33.75 ppm, ractopamine is effective in reducing the effect of oxidation during storage in the refrigerator or freezer.

O objetivo foi avaliar a influência do uso de ractopamina na alimentação de pacus (Piaractus mesopotaminus) na fase de terminação sobre alguns parâmetros de qualidade dos filés. Trinta e cinco animais com peso de 0,868±0,168kg foram distribuídos em delineamento inteiramente ao acaso com cinco tratamentos (0,0 - controle; 11,25; 22,50; 33,75 e 45ppm de ractopamina) e sete repetições, sendo a parcela representada por dois filés provenientes de um animal. As rações foram isoenergéticas e isoproteicas, e o tempo experimental foi de 90 dias. A ractopamina não influenciou (P>0,05) o pH inicial dos filés e nem após 24 horas. Comparado ao controle, a RAC aumentou (P<0,05) a umidade dos filés in natura e a oxidação lipídica dos mesmos quando armazenados por 12 dias em geladeira ou 60 dias em freezer. Na dose de 11,25 reduziu (P<0,05) o teor de extrato etéreo e, na dose de 45 ppm, reduziu (P<0,05) o de proteína bruta dos filés. Considerando somente a RAC, houve aumento linear (P<0,05) do teor de gordura e redução linear (P<0,05) da proteína bruta e perda de peso por cocção. Houve efeito quadrático (P<0,05) sobre o teor de cinzas, perda de peso por descongelamento e oxidação lipídica para os filés armazenados em geladeira ou em freezer, sendo 33,75 ppm o nível de RAC que resultou em menor índice de oxidação lipídica. Conclui-se que a ractopamina a 11,5 ppm é efetiva em reduzir o teor de lipídeos em filés de pacu, embora aumente a formação de peróxidos em amostras mantidas em freezer após 60 dias. A 33,75 ppm a ractopamina é efetiva em reduzir os efeitos da oxidação durante o armazenamento em geladeira ou freezer.

Effect of ractopamine on the chemical and physical characteristics of pacu(Piaractus mesopotamicus) steaks / Efeito da ractopamina sobre as características físicas e químicas de filés de pacu (Piaractus mesopotamicus)

The objective was to evaluate the use of ractopamine (RAC) in the diet for pacu (Piaractus mesopotaminus) in the finishing phase on some quality parameters of the fillets. Thirty-five animals weighing 0.868±0.168kg were distributed in a completely randomised design with five treatments (0.0 - control; 11.25, 22.50, 33.75 and 45 ppm of RAC) and seven replicates with two fillets obtained from the same animal. The diets were isocaloric and isoprotein and experimental time was 90 days. RAC did not affect (P>0.05) the initial pH or ph after 24 hours of the fillets. Compared to the control, RAC increased (P<0.05) the moisture content of the fillets in natura and lipid oxidation of samples stored for 12 days in the refrigerator or freezer for 60 days. The RAC in 11.25 ppm reduced (P<0.05) the lipid content, while 45 ppm reduced (P<0.05) the crude protein in the fillets. Considering only RAC, there was a linear increase (P<0.05) in the lipid content (P<0.05) and a linear reduction in crude protein and weight loss after cooking the fillets. There was a quadratic effect (P<0.05) on the ash content, weight loss and lipid oxidation in fillets stored in the refrigerator or freezer. A RAC dose of 33.75 ppm resulted in a lower lipid oxidation index. In conclusion, ractopamine at 11.25 ppm is effective for reducing the fat content in fillets of pacu, although it increases the formation of peroxides in samples kept in the freezer for longer than 60 days. At 33.75 ppm, ractopamine is effective in reducing the effect of oxidation during storage in the refrigerator or freezer.(AU)

O objetivo foi avaliar a influência do uso de ractopamina na alimentação de pacus (Piaractus mesopotaminus) na fase de terminação sobre alguns parâmetros de qualidade dos filés. Trinta e cinco animais com peso de 0,868±0,168kg foram distribuídos em delineamento inteiramente ao acaso com cinco tratamentos (0,0 - controle; 11,25; 22,50; 33,75 e 45ppm de ractopamina) e sete repetições, sendo a parcela representada por dois filés provenientes de um animal. As rações foram isoenergéticas e isoproteicas, e o tempo experimental foi de 90 dias. A ractopamina não influenciou (P>0,05) o pH inicial dos filés e nem após 24 horas. Comparado ao controle, a RAC aumentou (P<0,05) a umidade dos filés in natura e a oxidação lipídica dos mesmos quando armazenados por 12 dias em geladeira ou 60 dias em freezer. Na dose de 11,25 reduziu (P<0,05) o teor de extrato etéreo e, na dose de 45 ppm, reduziu (P<0,05) o de proteína bruta dos filés. Considerando somente a RAC, houve aumento linear (P<0,05) do teor de gordura e redução linear (P<0,05) da proteína bruta e perda de peso por cocção. Houve efeito quadrático (P<0,05) sobre o teor de cinzas, perda de peso por descongelamento e oxidação lipídica para os filés armazenados em geladeira ou em freezer, sendo 33,75 ppm o nível de RAC que resultou em menor índice de oxidação lipídica. Conclui-se que a ractopamina a 11,5 ppm é efetiva em reduzir o teor de lipídeos em filés de pacu, embora aumente a formação de peróxidos em amostras mantidas em freezer após 60 dias. A 33,75 ppm a ractopamina é efetiva em reduzir os efeitos da oxidação durante o armazenamento em geladeira ou freezer.(AU)

Ethylene synthesis inhibition effects on oxidative stress and in vitro conservation of Lippia filifolia (Verbenaceae).

This study aimed to investigate the effects of ethylene biosynthesis inhibitors on oxidative metabolisms and the in vitro conservation of Lippia filifolia, using the lipid peroxidation index (TBARS), antioxidative enzymes and pigments as biomarkers. We found that EDTA, sodium thiosulfate (STS) and especially Co had protective effects on oxidative stress in tissues cultured in vitro, resulting in a delay of the senescence and the reduction of subcultures frequency, contributing to the germplasm conservation of this species.

Ethylene synthesis inhibition effects on oxidative stress and in vitro conservation of Lippia filifolia (Verbenaceae) / Efeitos da inibição da síntese do etileno no estresse oxidativo e na conservação in vitro de Lippia filifolia (Verbenaceae)

This study aimed to investigate the effects of ethylene biosynthesis inhibitors on oxidative metabolisms and the in vitro conservation of Lippia filifolia, using the lipid peroxidation index (TBARS), antioxidative enzymes and pigments as biomarkers. We found that EDTA, sodium thiosulfate (STS) and especially Co had protective effects on oxidative stress in tissues cultured in vitro, resulting in a delay of the senescence and the reduction of subcultures frequency, con-tributing to the germplasm conservation of this species.(AU)

O objetivo deste estudo foi investigar os efeitos de inibidores da biossíntese do etileno no metabolismo oxidativo e na conservação in vitro de Lippia filifolia. Para isso, foram avaliados o índice de peroxidação lipídica (TBARS), a atividade de enzimas antioxidativas e o conteúdo de pigmentos fotossintéticos e de antocianinas. Os resultados evidenciaram que o EDTA, o tiossulfato de sódio (STS) e, especialmente, o Co apresentaram ação protetora sobre o estresse oxidativo nos tecidos, o que resultou em atraso no início da senescência das culturas e na redução da frequência dos subcultivos, contribuindo para a conservação do germoplasma dessa espécie.(AU)

Development and characterization of DNA microsatellite primers for buriti (Mauritia flexuosa L.f.).

Mauritia flexuosa L. (Arecaceae) is a palm tree species known as buriti that occurs in the Cerrado biome. It is characteristic of the vereda, a typical ecosystem of central Brazil. In this phytophysiognomy, M. flexuosa and other groups of arboreal-herbaceous species develop in open fields with very humid soils. M. flexuosa can be found in forest borders and is a palm tree with a wide distribution in South America (Brazil, Colombia, Venezuela, French Guyana Ecuador, Peru, and Bolivia). The main objectives of this study were to develop simple sequence repeat marker-enriched libraries and to characterize these loci in buriti palm to facilitate future population studies. A total of 40 sequences derived from the microsatellite-enriched libraries were selected for primer design. The optimization results showed that 9 primer pairs could successfully amplify polymorphic target fragments of the expected sizes. The data also show that the described primers can be used in population genetic studies in M. flexuosa to obtain information that will inform conservation and management strategies.

Relaxin in the male reproductive system

xin (RLN) belong s to a family of hormones structurally related to insulin and presents a broad spectrum of actions. H umans have three forms of RLN , encoded by three different genes ( RLN1 , RLN2 and RLN3 ) , but nonprimate vertebrate s have only two forms of relaxin (RLN1 and RLN3) . RLN1 of these animals is encoded by Rln1 , orthologous to the h uman RLN 2 gene , and both genes , Rln1 and human RLN2 , encode the major form of relaxin found in the male reproductive system . In the reproductive tract of human male s , RLN is mainly produced by the prostate and secreted into the seminal fluid, where it seems to play a role in sperm function. R LN may also play a role in prostate cancer progression. A lack of RLN in animal models impairs male fertili ty , and RLN knockout mice display decreased sperm maturation . T he precise role of RLN in the male reproductive system , however , is still far from clear. RLN actio n is due to its interaction with the G - protein coupled receptor RXFP1. Studies from our labora tory have shown that RLN and RXFP1 are e x pressed in rat Sertoli cells, and e x ogenous RLN stimulates Sertoli cell proliferation. RLN receptors can also be detected in rat germ cells at different stages of development, suggesting that RLN may play a direct r ole in spermatogenesis. The distribution of RLN/RXFP1 , however , appears to be species - dependent, because i n the boar testis RLN production seems restricted to the Leydig cells, whereas RXFP1 is found in Leydig, Sertoli and germ cells. The co - expression of RLN and RXFP1 in several regions of the male reproductive system suggest s that the peptide may act in an autocrine/paracrine fashion.