The contrasting phenotypes of neutrophils during asymptomatic versus symptomatic Leishmania braziliensis infection.

BACKGROUND: The mechanisms that mediate immune protection in individuals with subclinical (SC) or asymptomatic infection with L. braziliensis are largely unknown. Neutrophils (PMNs) have been implicated in progressive symptomatic cutaneous leishmaniasis (CL), but their potential participation in maintenance of subclinical infection is unexplored. The aim of this study was to compare the phenotypic and functional profiles of PMNs in individuals with SC infection versus patients with symptomatic CL due to L. braziliensis. METHODS: Subjects were recruited in the endemic region of Corte de Pedra, Bahia, Brazil. Surface markers to define activation status were characterized by flow cytometry. Functional responses of PMNs including phagocytic capacity, production of oxidative species, and oxidative killing of intracellular parasites were studied in vitro. RESULTS: PMNs from individuals with SC infection displayed a more activated phenotype and greater ability to control the infection than PMNs from patients with CL. In contrast, PMNs from patients with CL exhibited higher expression of HLA-DR and higher production of oxidative species than PMNs from subjects with SC infection. CONCLUSION: PMNs from individuals with SC infection can control the infection more efficiently than PMNs from patients with CL, despite the lower production of oxidants. Our observations suggest that L. braziliensis may evade microbicidal mechanisms of PMNs from patients with CL, contributing to parasite dissemination and the establishment of disease.

Sexual and Gender Minorities' Vaccine Uptake and Behavioral Change in Response to the Mpox Outbreak in the United States: August 2022 Through November 2022.

BACKGROUND: In the summer of 2022, the United States faced a nationwide outbreak of mpox, with cases concentrated in sexual and gender minorities who have sex with men. Understanding rates of mpox vaccine uptake and concomitant behavioral change is essential to guide the implementation of targeted public health responses to the potential reemergence of mpox. METHODS: Between August 2022 and November 2022, 8551 individuals recruited via geosocial networking apps completed a brief survey that assessed mpox vaccine uptake, intentions to get a mpox vaccine, and behavioral change. RESULTS: In August, 17.4% of participants reported having received at least 1 dose of the mpox vaccine. By November, this prevalence estimate was 35.0%. Black participants were significantly less likely to be vaccinated, and vaccine hesitancy increased among Black participants over time. Among those who had not yet received a vaccination, the intention to get vaccinated decreased over time. We observed trends that coincided with the evolving outbreak, such as decreased worry about mpox and less engagement in risk reduction behaviors over time. CONCLUSIONS: Despite a 2-fold increase in mpox vaccine uptake between August 2022 and November 2022 in sexual and gender minorities who have sex with men, disparities in vaccine uptake were observed among Black participants. Findings will guide the implementation of public health responses to the potential reemergence of mpox and other viral infectious diseases (eg, meningitis) with a specific focus on optimizing vaccine uptake in Black communities.

GIS-FA: an approach to integrating thematic maps, factor-analytic, and envirotyping for cultivar targeting.

KEY MESSAGE: We propose an "enviromics" prediction model for recommending cultivars based on thematic maps aimed at decision-makers. Parsimonious methods that capture genotype-by-environment interaction (GEI) in multi-environment trials (MET) are important in breeding programs. Understanding the causes and factors of GEI allows the utilization of genotype adaptations in the target population of environments through environmental features and factor-analytic (FA) models. Here, we present a novel predictive breeding approach called GIS-FA, which integrates geographic information systems (GIS) techniques, FA models, partial least squares (PLS) regression, and enviromics to predict phenotypic performance in untested environments. The GIS-FA approach enables: (i) the prediction of the phenotypic performance of tested genotypes in untested environments, (ii) the selection of the best-ranking genotypes based on their overall performance and stability using the FA selection tools, and (iii) the creation of thematic maps showing overall or pairwise performance and stability for decision-making. We exemplify the usage of the GIS-FA approach using two datasets of rice [Oryza sativa (L.)] and soybean [Glycine max (L.) Merr.] in MET spread over tropical areas. In summary, our novel predictive method allows the identification of new breeding scenarios by pinpointing groups of environments where genotypes demonstrate superior predicted performance. It also facilitates and optimizes cultivar recommendations by utilizing thematic maps.

PrEP Uptake and Methamphetamine Use Patterns in a 4-Year U.S. National Prospective Cohort Study of Sexual and Gender Minority People, 2017-2022.

Methamphetamine use is on the rise among sexual and gender minority people who have sex with men (SGMSM), escalating their HIV risk. Despite pre-exposure prophylaxis (PrEP) being an effective biomedical HIV prevention tool, its uptake in relation to methamphetamine use patterns in SGMSM has not been studied. In a U.S. cohort study from 2017 to 2022, 6,253 HIV-negative SGMSM indicated for but not using PrEP were followed for four years. Methamphetamine use was categorized (i.e., newly initiated, persistently used, never used, used but quit), and PrEP uptake assessed using generalized estimating equation (GEE), adjusted for attrition. Participants had a median age of 29, with 51.9% White, 11.1% Black, 24.5% Latinx, and 12.5% other races/ethnicities. Over the four years, PrEP use increased from 16.3 to 27.2%. GEE models identified risk factors including housing instability and food insecurity. In contrast, older age, health insurance, clinical indications, and prior PrEP use increased uptake. Notably, Latinx participants were more likely to use PrEP than Whites. Regarding methamphetamine use, those who newly initiated it were more likely to use PrEP compared to non-users. However, those who quit methamphetamine and those who persistently used it had PrEP usage rates comparable to those of non-users. Though PrEP uptake increased, it remained low in SGMSM. Methamphetamine use was associated with PrEP uptake. Healthcare providers should assess methamphetamine use for harm reduction. Prioritizing younger, uninsured SGMSM and addressing basic needs can enhance PrEP uptake and reduce HIV vulnerabilities.

Lessons from the invasion front: Integration of research and management of the lionfish invasion in Brazil.

After successful invasions in the Caribbean and Mediterranean, lionfish (Pterois spp.) have recently invaded another important biogeographical region -the Brazilian Province. In this article, we discuss this new invasion, focusing on a roadmap for urgent mitigation of the problem, as well as focused research and management strategies. The invasion in Brazil is already in the consolidation stage, with 352 individuals recorded so far (2020-2023) along 2766 km of coastline. This includes both juveniles and adults, including egg-bearing females, ranging in length from 9.1 to 38.5 cm. Until now, most of the records in the Brazilian coast occurred in the equatorial southwestern Atlantic (99%), mainly on the Amazon mesophotic reefs (15% of the records), northeastern coast of Brazil (45%), and the Fernando de Noronha Archipelago (41%; an UNESCO World Heritage Site with high endemism rate). These records cover a broad depth range (1-110 m depth), twelve protected areas, eight Brazilian states (Amapá, Pará, Maranhão, Piauí, Ceará, Rio Grande do Norte, Paraíba, and Pernambuco) and multiple habitats (i.e., mangrove estuaries, shallow-water and mesophotic reefs, seagrass beds, artificial reefs, and sandbanks), indicating a rapid and successful invasion process in Brazilian waters. In addition, the lack of local knowledge of rare and/or cryptic native species that are potentially vulnerable to lionfish predation raises concerns regarding the potential overlooked ecological impacts. Thus, we call for an urgent integrated approach with multiple stakeholders and solution-based ecological research, real-time inventories, update of environmental and fishery legislation, participatory monitoring supported by citizen science, and a national and unified plan aimed at decreasing the impact of lionfish invasion. The experience acquired by understanding the invasion process in the Caribbean and Mediterranean will help to establish and prioritize goals for Brazil.

ApoA1 Neutralizes Proinflammatory Effects of Dengue Virus NS1 Protein and Modulates Viral Immune Evasion.

Dengue is a mosquito-borne infectious disease that is highly endemic in tropical and subtropical countries. Symptomatic patients can rapidly progress to severe conditions of hemorrhage, plasma extravasation, and hypovolemic shock, which leads to death. The blood tests of patients with severe dengue typically reveal low levels of high-density lipoprotein (HDL), which is responsible for reverse cholesterol transport (RCT) and regulation of the lipid composition in peripheral tissues. It is well known that dengue virus (DENV) depends on membrane cholesterol rafts to infect and to replicate in mammalian cells. Here, we describe the interaction of DENV nonstructural protein 1 (NS1) with apolipoprotein A1 (ApoA1), which is the major protein component of HDL. NS1 is secreted by infected cells and can be found circulating in the serum of patients with the onset of symptoms. NS1 concentrations in plasma are related to dengue severity, which is attributed to immune evasion and an acute inflammatory response. Our data show that the DENV NS1 protein induces an increase of lipid rafts in noninfected cell membranes and enhances further DENV infection. We also show that ApoA1-mediated lipid raft depletion inhibits DENV attachment to the cell surface. In addition, ApoA1 is able to neutralize NS1-induced cell activation and to prevent NS1-mediated enhancement of DENV infection. Furthermore, we demonstrate that the ApoA1 mimetic peptide 4F is also capable of mediating lipid raft depletion to control DENV infection. Taken together, our results suggest the potential of RCT-based therapies for dengue treatment. These results should motivate studies to assess the importance of RCT in DENV infection in vivo. IMPORTANCE DENV is one of the most relevant mosquito-transmitted viruses worldwide, infecting more than 390 million people every year and leading to more than 20 thousand deaths. Although a DENV vaccine has already been approved, its potential side effects have hampered its use in large-scale immunizations. Therefore, new treatment options are urgently needed to prevent disease worsening or to improve current clinical management of severe cases. In this study, we describe a new interaction of the NS1 protein, one of the major viral components, with a key component of HDL, ApoA1. This interaction seems to alter membrane susceptibility to virus infection and modulates the mechanisms triggered by DENV to evade the immune response. We also propose the use of a mimetic peptide named 4F, which was originally developed for atherosclerosis, as a potential therapy for relieving DENV symptoms.

Transgender Individuals and Digital Health.

PURPOSE OF REVIEW: The goal of this review is to assess the use of digital technologies to promote the health and well-being of transgender and gender diverse (TGD) people. RECENT FINDINGS: TGD individuals experience numerous health disparities, including low uptake of HIV prevention strategies, such as pre-exposure prophylaxis, increased HIV incidence, and suboptimal HIV-related outcomes. These health disparities are the result of widespread intersectional stigma on the basis of gender identity, gender expression, socioeconomic class, race, and ethnicity, which negatively impact access to general medical and transgender-specific health care. TGD individuals often delay or avoid essential medical services due to fear of discrimination. Clinicians frequently lack training, competence, and skills in transgender medicine, further exacerbating the health disparities faced by TGD people. Digital technologies have been used to improve research and clinical care for TGD populations through various modalities; telemedicine, telehealth and mHealth. Digital health technologies, including HIT-enabled clinical decision support, telehealth, telemedicine, and mHealth, offer innovative ways to improve health care access, improve quality of care, and reduce health disparities for TGD populations, including and beyond HIV outcomes, through enhanced care delivery, clinician education, and enhancing social support networks.

Association mapping and genomic selection for sorghum adaptation to tropical soils of Brazil in a sorghum multiparental random mating population.

KEY MESSAGE: A multiparental random mating population used in sorghum breeding is amenable for the detection of QTLs related to tropical soil adaptation, fine mapping of underlying genes and genomic selection approaches. Tropical soils where low phosphorus (P) and aluminum (Al) toxicity limit sorghum [Sorghum bicolor (L.) Moench] production are widespread in the developing world. We report on BRP13R, a multiparental random mating population (MP-RMP), which is commonly used in sorghum recurrent selection targeting tropical soil adaptation. Recombination dissipated much of BRP13R's likely original population structure and average linkage disequilibrium (LD) persisted up to 2.5 Mb, establishing BRP13R as a middle ground between biparental populations and sorghum association panels. Genome-wide association mapping (GWAS) identified conserved QTL from previous studies, such as for root morphology and grain yield under low-P, and indicated the importance of dominance in the genetic architecture of grain yield. By overlapping consensus QTL regions, we mapped two candidate P efficiency genes to a ~ 5 Mb region on chromosomes 6 (ALMT) and 9 (PHO2). Remarkably, we find that only 200 progeny genotyped with ~ 45,000 markers in BRP13R can lead to GWAS-based positional cloning of naturally rare, subpopulation-specific alleles, such as for SbMATE-conditioned Al tolerance. Genomic selection was found to be useful in such MP-RMP, particularly if markers in LD with major genes are fitted as fixed effects into GBLUP models accommodating dominance. Shifts in allele frequencies in progeny contrasting for grain yield indicated that intermediate to minor-effect genes on P efficiency, such as SbPSTOL1 genes, can be employed in pre-breeding via allele mining in the base population. Therefore, MP-RMPs such as BRP13R emerge as multipurpose resources for efficient gene discovery and deployment for breeding sorghum cultivars adapted to tropical soils.

Predictors of Event-Driven Regimen Choice in Current PrEP Users and Sexual Behavior Characteristics of MSM Receiving Sexual Health Services in New York City.

While daily PrEP is undeniably effective, broad-based adoption remains low. Non-daily PrEP modalities, like event-driven PrEP (ED PrEP), offer an efficient way to deliver PrEP's protection to priority populations. We carried out an at-home survey with patients receiving sexual health services in a LGBTQ-clinic in New York (n = 147). Participants answered questions on ED PrEP awareness and preferences, sexual behavior, and sexual preparatory practices. Only 50% of our sample were aware of ED PrEP, about 30% met eligibility for ED PrEP, and 35% chose ED PrEP as a good HIV prevention option for them. In a robust Poisson model (n = 128), endorsement of ED PrEP as a good prevention choice was significantly more common in participants who were uninsured, preferred taking PrEP only when needed, and those who had concerns about side-effects. Furthermore, participants reported many sexual behaviors patterns and preparatory practices compatible with use of ED PrEP.

RESUMEN: Si bien la PrEP diaria es innegablemente efectiva, la adopción generalizada sigue siendo baja. Las modalidades de PrEP no diarias, como la PrEP impulsada por eventos (ED PrEP), ofrecen una manera eficiente de brindar protección de PrEP a las poblaciones prioritarias. Realizamos una encuesta a domicilio con pacientes que recibían servicios de salud sexual en una clínica LGBTQ en Nueva York (n = 147). Los participantes respondieron preguntas sobre su conocimiento y sus preferencias de la ED PrEP, su comportamiento sexual, y sus prácticas de preparación sexual. Solo el 50% de nuestra muestra conocía la ED PrEP, alrededor del 30% cumplía con los requisitos para la ED PrEP, y el 35% eligió ED PrEP como una buena opción de prevención del HIV para ellos. En un modelo robusto de Poisson (n = 128), la aprobación de la ED PrEP como una buena opción de prevención fue significativamente más común en los participantes que no tenían seguro, preferían tomar la PrEP solo cuando era necesario, y aquellos que tenían preocupaciones sobre los efectos secundarios. Además, los participantes informaron muchos patrones de comportamiento sexual y prácticas preparatorias compatibles con el uso de ED PrEP.

Awareness and Acceptability of Undetectable = Untransmittable Among a U.S. National Sample of HIV-Negative Sexual and Gender Minorities.

While the "Undetectable = Untransmittable" (U=U) message is widely endorsed, little is known about its breadth and reach. Our study describes socio-demographic characteristics and sexual behaviors associated with having heard of and trusting in U =U in a U.S. national sample of HIV-negative participants. Data were derived from the Together 5,000 cohort study, an internet-based U.S. national cohort of cis men, trans men and trans women who have sex with men. Approximately 6 months after enrollment, participants completed an optional survey included in the present cross-sectional analysis (n = 3286). Measures included socio-demographic and healthcare-related characteristics; questions pertaining to knowledge of and trust in U=U (dependable variable). We used descriptive statistics and multivariable logistic models to identify characteristics associated with these variables and explored patterns in willingness to engage in condomless anal sex (CAS) with regard to trust in U=U. In total, 85.5% of participants reported having heard of U=U. Among those aware of U=U, 42.3% indicated they trusted it, 19.8% did not, and 38.0% were unsure about it. Latinx, Asian, lower income, and Southern participants were less likely to have heard of U=U. Having had a recent clinical discussion about PrEP or being a former-PrEP user were associated with trust in U=U. Willingness to engage in CAS was positively associated with trust in U=U, and varied based on the partner's serostatus, PrEP use and viral load. Although we found high rates of awareness and low levels of distrust, our study indicated that key communities remain unaware and/or skeptical of U=U.

RESUMEN: Mientras que el mensaje de "Indetectable=Intransmisible" (I=I) es ampliamente respaldado, poco se conoce acerca de su alcance y amplitud. Nuestro estudio describe características socio-demográficas y los comportamientos sexuales asociados con haber escuchado de y confiar en I=I en una muestra nacional Estadounidense de participantes VIH-negativos. Los datos se derivaron de Together 5,000, un estudio cohorte en donde se recopiló datos de un cohorte basado en internet de hombres cis, hombres trans y mujeres trans que tienen sexo con otros hombres. Aproximadamente 6 meses después de la inscripción, los participantes completaron una encuesta opcional cuyos datos son presentados en este análisis transversal (n = 3286). Los instrumentos incluyeron características socio-demografías y relacionadas al cuidado de la salud; preguntas pertinentes al conocimiento de y confianza en I=I (variable dependiente). Usamos estadísticas descriptivas y modelos logísticos multivariables para identificar características asociadas a estas variables y exploramos los patrones en la disposición a participar de sexo anal sin condones (CAS) con respecto a la confianza en I=I. En total, 85.5% de los participantes reportaron haber escuchado de I=I. Entre esos, 42.3% indicó que confiaban en el mensaje, 19.8% no confiaban, y 38.0% estaban inseguros. Los participantes latinx, asiáticos, de bajos recursos y del sur tenían menos probabilidad de haber escuchado de I=I. El haber tenido una discusión clínica reciente sobre PrEP o el ser un ex usuario de PrEP se asociaron con la confianza en I=I. La disposición a participar de CAS se asoció positivamente con la confianza en I=I, y varió en función del estado serológico de las parejas, el uso de PrEP y la carga viral. Aunque encontramos altas tasas de conciencia y bajos niveles de desconfianza, nuestro estudio indicó que comunidades clave siguen sin conocer y/o escépticas de I=I.

Factors Associated with Being PrEP-Naïve Among a U.S. National Cohort of Former-PrEP and PrEP-Naïve Participants Meeting Objective Criteria for PrEP Care.

There is an urgent need to increase uptake and persistence in HIV pre-exposure prophylaxis (PrEP) in PrEP-eligible candidates. Little is known about the similarities and differences between groups of PrEP-naïve and former users, an important consideration for future interventions. We explored factors associated with being PrEP-naïve in a U.S. national cohort of naïve and former-PrEP users, all of whom met objective criteria for PrEP care at enrollment. Data were derived from the Together 5000 cohort study, an Internet-based U.S. national cohort of cisgender and trans men and trans women who have sex with men. Participants were recruited via ads on men-for-men geosocial networking apps. All participants were not on PrEP at the time of enrollment. We conducted bivariate analysis to explore differences between the two groups and used multivariable logistic regression to assess factors associated with being PrEP-naïve. Of the 6283 participants, 5383 (85.7%) were PrEP-naïve and 900 (14.3%) were former-PrEP users. There were significant differences between PrEP-naïve and former-PrEP users across multiple demographic variables, in addition to PrEP-related and psychosocial variables. Factors associated with being PrEP-naïve included younger age, sexual identity other than gay/queer, lower perception of candidacy for PrEP care, less willingness to take PrEP, lower access to PrEP care, and individual-level barriers such as health- and provider-related concerns. Programs and policies designed to address uptake and persistence of PrEP should be aware of these differences. Providing care in non-traditional LGBTQ-care settings, home-based PrEP interventions, and provision by healthcare providers other than physicians could improve uptake. Future research should investigate mechanisms that can improve uptake and persistence in communities in need of PrEP.

Getting Clear About Rectal Douching Among Men Who Have Sex With Men.

Receptive anal sex is the primary means through which HIV is transmitted among men who have sex with men (MSM). Recently, researchers have begun investigating the role that rectal douching may play in amplifying risk for transmission. Yet, there is limited research on the frequency with which MSM douche, the products they use, and how this may vary across sociodemographic characteristics. A U.S. national sample of 4745 MSM completed an online survey that assessed their douching behavior, demographic characteristics, sexual behavior, and their anal sexual positioning (i.e., top, bottom, versatile). Nearly two-thirds (65.8%) had engaged in rectal douching in the last three months. Among those who douched, water was commonly reported (84.2%) and 20.1% reported using commercial enemas (e.g., Fleet), as well as water and soap (15.0%)-numbers exceed 100% as some participants reported more than one. Men who douched reported significantly more receptive and insertive condomless anal sex acts in the prior 3 months. One-in-ten men reported rectal bleeding after douching. Compared to HIV-negative participants who had not taken PrEP, participants had higher odds of reporting douching in the past 3 months if they were HIV-negative and currently on PrEP (AOR = 1.82), HIV-negative and previously used PrEP (AOR = 1.58), and HIV-positive (AOR = 1.83). Douching was common in this sample. Given that douching could amplify risk for HIV transmission, healthcare providers should discuss douching safety with their patients, with a focus on harm reduction (e.g., reduce risk of bleeding, as opposed to abstinence from douching).

Sources, Spectrum, Genetics, and Inheritance of Phaseolus vulgaris Resistance Against Xanthomonas citri pv. fuscans.

Common bean (Phaseolus vulgaris) is one of the most consumed agricultural products in the world. Its production is affected by common bacterial blight (CBB) caused by Xanthomonas citri pv. fuscans and X. phaseoli pv. phaseoli. In this work, we investigated the spectrum, genetics, and inheritance of common bean resistance to X. citri pv. fuscans. Inoculation of nine selected cultivars with an X. citri pv. fuscans strain showed that BRS Radiante and IAPAR 16 were resistant. These two cultivars were also resistant to six X. phaseoli pv. phaseoli strains of different geographic origins, demonstrating their broad-spectrum resistances. BRS Radiante sustained smaller X. citri pv. fuscans populations than two susceptible cultivars. Stomatal densities of IAPAR 16 and BRS Radiante were significantly higher than or not different from susceptible cultivars. BRS Radiante showed the lowest general combining ability values and the combination BRS Radiante × Carioca MG the lowest specific combining ability (SCA) values, revealing the capacity of BRS Radiante to increase resistance to X. citri pv. fuscans. Positive and negative parental SCA values indicated dominant and recessive genes involved in X. citri pv. fuscans resistance. Resistance of the BRS Radiante × Carioca MG cross segregated in a 9:7 ratio in the F2 population, indicating that it is governed by two complementary dominant genes. Maximum likelihood analysis showed that the resistance of BRS Radiante to X. citri pv. fuscans is conferred by a gene of major effect with contribution of additional polygenes. This study contributes with important knowledge on the resistance against CBB in Brazilian common bean cultivars as well as with molecular tools for confirmation of common bean hybrids.

The genetic architecture of phosphorus efficiency in sorghum involves pleiotropic QTL for root morphology and grain yield under low phosphorus availability in the soil.

BACKGROUND: Phosphorus (P) fixation on aluminum (Al) and iron (Fe) oxides in soil clays restricts P availability for crops cultivated on highly weathered tropical soils, which are common in developing countries. Hence, P deficiency becomes a major obstacle for global food security. We used multi-trait quantitative trait loci (QTL) mapping to study the genetic architecture of P efficiency and to explore the importance of root traits on sorghum grain yield on a tropical low-P soil. RESULTS: P acquisition efficiency was the most important component of P efficiency, and both traits were highly correlated with grain yield under low P availability. Root surface area was positively associated with grain yield. The guinea parent, SC283, contributed 58% of all favorable alleles detected by single-trait mapping. Multi-trait mapping detected 14 grain yield and/or root morphology QTLs. Tightly linked or pleiotropic QTL underlying the surface area of fine roots (1-2 mm in diameter) and grain yield were detected at positions 1-7 megabase pairs (Mb) and 71 Mb on chromosome 3, respectively, and a root diameter/grain yield QTL was detected at 7 Mb on chromosome 7. All these QTLs were near sorghum homologs of the rice serine/threonine kinase, OsPSTOL1. The SbPSTOL1 genes on chromosome 3, Sb03g006765 at 7 Mb and Sb03g031690 at 60 Mb were more highly expressed in SC283, which donated the favorable alleles at all QTLs found nearby SbPSTOL1 genes. The Al tolerance gene, SbMATE, may also influence a grain yield QTL on chromosome 3. Another PSTOL1-like gene, Sb07g02840, appears to enhance grain yield via small increases in root diameter. Co-localization analyses suggested a role for other genes, such as a sorghum homolog of the Arabidopsis ubiquitin-conjugating E2 enzyme, phosphate 2 (PHO2), on grain yield advantage conferred by the elite parent, BR007 allele. CONCLUSIONS: Genetic determinants conferring higher root surface area and slight increases in fine root diameter may favor P uptake, thereby enhancing grain yield under low-P availability in the soil. Molecular markers for SbPSTOL1 genes and for QTL increasing grain yield by non-root morphology-based mechanisms hold promise in breeding strategies aimed at developing sorghum cultivars adapted to low-P soils.

Unraveling candidate genes underlying biomass digestibility in elephant grass (Cenchrus purpureus).

BACKGROUND: Elephant grass [Cenchrus purpureus (Schumach.) Morrone] is used for bioenergy and animal feed. In order to identify candidate genes that could be exploited for marker-assisted selection in elephant grass, this study aimed to investigate changes in predictive accuracy using genomic relationship information and simple sequence repeats for eight traits (height, green biomass, dry biomass, acid and neutral detergent fiber, lignin content, biomass digestibility, and dry matter concentration) linked to bioenergetics and animal feeding. RESULTS: We used single-step, genome-based best linear unbiased prediction and genome association methods to investigate changes in predictive accuracy and find candidate genes using genomic relationship information. Genetic variability (p < 0.05) was detected for most of the traits evaluated. In general, the overall means for the traits varied widely over the cuttings, which was corroborated by a significant genotype by cutting interaction. Knowing the genomic relationships increased the predictive accuracy of the biomass quality traits. We found that one marker (M28_161) was significantly associated with high values of biomass digestibility. The marker had moderate linkage disequilibrium with another marker (M35_202) that, in general, was detected in genotypes with low values of biomass digestibility. In silico analysis revealed that both markers have orthologous regions in other C4 grasses such as Setaria viridis, Panicum hallii, and Panicum virgatum, and these regions are located close to candidate genes involved in the biosynthesis of cell wall molecules (xyloglucan and lignin), which support their association with biomass digestibility. CONCLUSIONS: The markers and candidate genes identified here are useful for breeding programs aimed at changing biomass digestibility in elephant grass. These markers can be used in marker-assisted selection to grow elephant grass cultivars for different uses, e.g., bioenergy production, bio-based products, co-products, bioactive compounds, and animal feed.

Resistance of the wild tomato Solanum habrochaites to Phytophthora infestans is governed by a major gene and polygenes.

This work aimed to study the inheritance of resistance to Phytophthora infestans in tomato plants, using the maximum likelihood estimation function. The susceptible cultivar Santa Clara (Solanum lycopersicum) was used as the female genitor and the P. infestans resistant S. habrochaites f. glabratum accession (BGH 6902) as the male genitor. F1 plants from the crossing were self-pollinated to produce F2 progenies, and also backcrossed with PR and PS to produce BC1:R and BC1:S generations, respectively. The tomato plants were inoculated 50 days after transplanting. Disease severity was evaluated via a diagrammatic scale. Comparison of the genetic models created using the maximum likelihood function revealed that the inheritance of resistance to P. infestans in S. habrochaites is conferred by a major gene with additive and dominance effects, polygenes with additive effects, plus the environmental effect. Vertical resistance can be explored using genes with major effects. Programs of recurrent and maker-assisted selection are considered efficient strategies with which to select genotypes that hold P. infestans resistance conferred by polygenes.

Evaluation of multiwalled carbon nanotubes toxicity in two fish species.

Carbon Nanotubes are among the most promising materials for the technology industry. Their unique physical and chemical proprieties may reduce the production costs and improve the efficiency of a large range of products. However, the same characteristics that have made nanomaterials interesting for industry may be responsible for inducing toxic effects on the aquatic organisms. Since the carbon nanotubes toxicity is still a controversial issue, we performed tests of acute and subchronic exposure to a commercial sample of multiwalled carbon nanotubes in two fish species, an exotic model (Danio rerio) and a native one (Astyanax altiparanae). Using the alkaline version of the comet assay on erythrocytes and the piscine micronucleous, also performed on erythrocytes, it was verified that the tested carbon nanotubes sample did not generate apparent genotoxicity by means of single/double DNA strand break or clastogenic/aneugenic effects over any of the species, independently of the exposure period. Although, our findings indicate the possibility of the occurrence of CNTs-DNA crosslinks. Apparently, the sample tested induces oxidative stress after subchronic exposure as shown by activity of superoxide dismutase and catalase. The data obtained by the activity levels of acetylcholinesterase suggests acute neurotoxicity in Astyanax altiparanae and subchronic neurotoxicity in Danio rerio.

Bulk hydrogen stable isotope composition of seaweeds: Clear separation between Ulvophyceae and other classes.

Little is known about the bulk hydrogen stable isotope composition (δ2 H) of seaweeds. This study investigated the bulk δ2 H in several different seaweed species collected from three different beaches in Brazil, Australia, and Argentina. Here, we show that Ulvophyceae (a group of green algae) had lower δ2 H values (between -94‰ and -130‰) than red algae (Florideophyceae), brown algae (Phaeophyceae), and species from the class Bryopsidophyceae (another group of green algae). Overall the latter three groups of seaweeds had δ2 H values between -50‰ and -90‰. These findings were similar at the three different geographic locations. Observed differences in δ2 H values were probably related to differences in hydrogen (H) metabolism among algal groups, also observed in the δ2 H values of their lipids. The marked difference between the δ2 H values of Ulvophyecae and those of the other groups could be useful to trace the food source of food webs in coastal rocky shores, to assess the impacts of green tides on coastal ecosystems, and to help clarify aspects of their phylogeny. However, reference materials for seaweed δ2 H are required before the full potential of using the δ2 H of seaweeds for ecological studies can be exploited.

Immunologic Markers of Protection in Leishmania (Viannia) braziliensis Infection: A 5-Year Cohort Study.

BACKGROUND: The control of Leishmania braziliensis by individuals with subclinical infection (SC) are unknown. METHODS: A cohort of 308 household contacts (HCs) of patients with cutaneous leishmaniasis (CL) was established in 2010 in an endemic area and followed up for 5 years. Whole-blood cultures stimulated with soluble Leishmania antigen and a Leishmania skin test (LST) were performed in years 0, 2, and 4. The identification of the lymphocyte subsets secreting interferon (IFN) γ and the ability of monocytes to control Leishmania were determined. RESULTS: During follow-up, 118 subjects (38.3%) had evidence of L. braziliensis infection. Of the HCs, CL was documented in 45 (14.6%), 101 (32.8%) had SC infection, and 162 (52.6%) did not have evidence of exposure to L. braziliensis The ratio of infection to disease was 3.2:1. IFN-γ production, mainly by natural killer cells, was associated with protection, and a positive LST result did not prevent development of disease. Moreover, monocytes from subjects with SC infection were less permissive to parasite penetration and had a greater ability to control L. braziliensis than cells from patients with CL. CONCLUSIONS: Protection against CL was associated with IFN-γ production, negative LST results, impaired ability of Leishmania to penetrate monocytes, and increased ability to control Leishmania growth.