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Cannibalistic behaviour between tadpoles of dendrobatoid poison frogs has been observed in several species with complex parental care dynamics, leading to the idea that it may have played a role in the evolution of parental care. However, the existence or characteristics of this behaviour beyond a handful of well-studied species remains largely unknown. I report direct and indirect observations of larval cannibalism in two species of the genus Phyllobates, which seem to occur less frequently than in other, better studied species, and possibly associated with body size differences. Beyond expanding the phylogenetic breadth of tadpole cannibalism among poison frogs, my observations point to interesting aspects of this behaviour, such as its apparently plastic and continuous nature, and highlight the importance of studying other lineages to understand the its drivers and effects on poison frog evolution.

Antecedentes y Objetivos: México presenta acumulaciones de materiales tóxicos e inestables desechados por la minería, llamados jales, representando un riesgo potencial y efectivo para los ecosistemas y la sociedad. La restauración ecológica en combinación con otras estrategias de mitigación ofrece una alternativa para disminuir estos impactos ambientales y revertir la degradación del ecosistema por los jales. Este trabajo plantea algunas consideraciones y propone una metodología para aplicar la restauración ecológica a los jales.Métodos: Se describieron las afectaciones y riesgos ocasionados por el depósito de jales a partir de las características de los materiales y del ecosistema donde se depositan, aplicando y adecuando criterios como los utilizados en la Evaluación del Impacto Ecológico. A partir de esto, se plantearon algunas consideraciones para mitigar los jales. También se analizaron las limitaciones de algunas técnicas de mitigación con organismos o materia orgánica, por sus impactos colaterales potenciales.Resultados clave: La propuesta metodológica considera acciones de mitigación de un jal que integren al ecosistema y su funcionamiento, dirigidos hacia una restauración ecosistémica. Por una parte, estos lineamientos consideran aspectos relacionados con la toxicidad y estabilidad de los jales y, por la otra, características y procesos ecosistémicos afectados por su depósito. Esta propuesta considera diez pasos que incorporan distintos aspectos que deben abordarse para la restauración en los depósitos de jales.Conclusiones: Mediante un enfoque ecosistémico, como en la restauración ecológica, se resuelven los problemas ambientales de contaminación e inestabilidad de los jales. Evitando también los impactos colaterales de las propias estrategias de mitigación como la creación de trampas ecológicas o haciendo biodisponibles los contaminantes, introduciéndolos a la cadena trófica sin compensar los impactos ecosistémicos provocados por su depósito.

Farm succession involves the interaction of social, economic, and emotional factors. The process also includes the decisions of farmers and their families who consider the farm as patrimony rather than a productive asset. This article analyses the processes of succession in farms of central Mexico to understand the different stages they comprise and the problems that these processes encounter. We conducted 12 in-depth interviews with producers who went through a recent transfer process. Succession processes and their associated factors were analyzed and discussed using the multiple case study methodology; subsequently, the stages that comprise each of these processes were defined. Results show that succession is commonly managed without making decisions or taking actions that prevent future problems, and individual interests of the potential heirs prevail. Although each transfer process is different, two basic types were identified: the spouse or the descendants assume the administration of the patrimony. However, in the analyzed cases, we found that, in general, there is no planning for succession, so the successors lack training in agricultural activities. In general, succession processes are complex and generate conflicts, and their trajectory depends on family relationships and the socioeconomic conditions of the farm.

Most of the farmers who grow cactus pear (Opuntia albicarpa) use manure as a fertilizer. This practice increases the problems of pests. The use of endomycorrhiza (Glomus intraradices) is almost unknown to farmers. Therefore, the objective of this research was to study the effect of the application with organic matter (OM) and inoculation with endomycorrhiza in cactus pear. The study was conducted under greenhouse conditions at the Montecillo Campus of the Postgraduate College, Mexico. Two types of soil from San Luis Potosí, Mexico were used, one of reddish coloration (xerosol) and another gray (lithosol). The results show that there were significant differences (p ≤ 0.05) in all the variables by the inoculation with endomycorrhiza, and in the majority of those by the application of OM. Both the mycorrhiza and the application of OM, as vermicompost, promoted a greater growth of the stem and the root. The types of soils used did not affect the growth of the plants. The mycorrhiza can be useful to improve mineral nutrition, and thus increase yields in the cactus pear plantations. In addition, these fungi can increase yields, and help reduce production costs. The application of 50 t ha-1 of vermicompost is a better alternative to add nutrients and OM to this crop.

In this article, the gelation potential of three coumarin derivatives in a variety of solvents was studied. We have found that, of these three compounds, ethyl 7-hydroxy-2-oxo-2H-chromene-3-carboxylate (2a) and ethyl 7-methoxy-2-oxo-2H-chromene-3-carboxylate (3a) were able to form gels in the same solvents (cyclohexanol, octanol, and DMSO/water), while ethyl 2-oxo-2H-chromene-3-carboxylate (1a) only formed in one, thus observing the influence of the substitute in position seven. One of them (2a) has unusual mechanical properties since it can be subjected to compressive forces and return to its initial state, something rare to observe in this type of material. In addition, during the formation of one of the gels, an additional process was observed during the sol–gel transition which is interrupted by a third stage in which a precipitate is formed, this precipitate requires a rearrangement to subsequently obtain the corresponding gel. The characterization of the gels by SEM revealed fibrillar structures in one of the compounds (2a) while in the other crystals they showed 2D structures. On the other hand, the use of different spectroscopic and computational techniques demonstrated the importance of hydrogen bond formation and π–π stacking for the formation of the internal structure of the gel.

Background. The floristic composition of the cacao (Theobroma cacao L.) agroforestry systems in Tabasco provides a way to describe the genetic and tree diversity of traditional forms of production. Objective. to evaluate how the cacao agroforestry systems are floristically composed in the state. Methodology. Thirteen plots were sampled in four municipalities, with a total area of 30.5 ha. The species were counted, and the importance, diameter classes, height, and main uses were estimated. Results. Seventeen families and 2370 individuals belonging to 36 species were recorded. The dominant families were Fabaceae and Rutaceae; The species with the highest presence (74.5%) were represented by Cedrela odorata L, Erythrina americana Mill., Gliricidia sepium (Jacq.) Walp., Tabebuia rosea (Bertol) DC., Swietenia macrophylla Willd., Cocos nucifera L, Colubrina arborescens (P. Mill) Sarg., Pimenta dioica L., Cecropia obtusifolia Bertol and Roystonea dunlapiana P. H. Allen. In addition to providing shade, trees are used to obtain wood, fruit, fencing, or similar medicinal alternatives. On average, each plot has 46 trees per ha, a diversity of 9 different shade trees in young plantations, and 18 species in mature plantations, demonstrating the variety and floristic richness in the agroecosystem. Implications. It lays the foundations for future work that quantifies and enhances the environmental services provided by agroecosystems, as its utility on cacao agroforestry systems to preserve wildlife species. Conclusion. More studies should be implemented to deepen the knowledge of cocoa agroforestry systems (CAFS), particularly in quantifying and providing environmental services. Maintaining these CAFS will promote biodiversity and other environmental benefits, such as carbon storage, which with integrative plans, can represent alternative sources of income for producers in a sustainable way."Background. The floristic composition of the cacao (Theobroma cacao L.) agroforestry systems in Tabasco provides a way to describe the genetic and tree diversity of traditional forms of production. Objective. to evaluate how the cacao agroforestry systems are floristically composed in the state. Methodology. Thirteen plots were sampled in four municipalities, with a total area of 30.5 ha. The species were counted, and the importance, diameter classes, height, and main uses were estimated. Results. Seventeen families and 2370 individuals belonging to 36 species were recorded. The dominant families were Fabaceae and Rutaceae; The species with the highest presence (74.5%) were represented by Cedrela odorata L, Erythrina americana Mill., Gliricidia sepium (Jacq.) Walp., Tabebuia rosea (Bertol) DC., Swietenia macrophylla Willd., Cocos nucifera L, Colubrina arborescens (P. Mill) Sarg., Pimenta dioica L., Cecropia obtusifolia Bertol and Roystonea dunlapiana P. H. Allen. In addition to providing shade, trees are used to obtain wood, fruit, fencing, or similar medicinal alternatives. On average, each plot has 46 trees per ha, a diversity of 9 different shade trees in young plantations, and 18 species in mature plantations, demonstrating the variety and floristic richness in the agroecosystem. Implications. It lays the foundations for future work that quantifies and enhances the environmental services provided by agroecosystems, as its utility on cacao agroforestry systems to preserve wildlife species. Conclusion. More studies should be implemented to deepen the knowledge of cocoa agroforestry systems (CAFS), particularly in quantifying and providing environmental services. Maintaining these CAFS will promote biodiversity and other environmental benefits, such as carbon storage, which with integrative plans, can represent alternative sources of income for producers in a sustainable way."

Field biology is an area of research that involves working directly with living organisms in situ through a practice known as “fieldwork.” Conducting fieldwork often requires complex logistical planning within multiregional or multinational teams, interacting with local communities at field sites, and collaborative research led by one or a few of the core team members. However, existing power imbalances stemming from geopolitical history, discrimination, and professional position, among other factors, perpetuate inequities when conducting these research endeavors. After reflecting on our own research programs, we propose four general principles to guide equitable, inclusive, ethical, and safe practices in field biology: be collaborative, be respectful, be legal, and be safe. Although many biologists already structure their field programs around these principles or similar values, executing equitable research practices can prove challenging and requires careful consideration, especially by those in positions with relatively greater privilege. Based on experiences and input from a diverse group of global collaborators, we provide suggestions for action-oriented approaches to make field biology more equitable, with particular attention to how those with greater privilege can contribute. While we acknowledge that not all suggestions will be applicable to every institution or program, we hope that they will generate discussions and provide a baseline for training in proactive, equitable fieldwork practices.

Objective: To identify the success and resilience factors of rural enterprises in Mexico in order to contribute to the theoretical and empirical differentiation of these concepts. Design/Methodology/Approach: We used the National Network for Sustainable Rural Development Companies as a case study to formulate key questions to identify their success and business resilience factors. Results: Permanent job creation turned out to be the main success factor, and timely delivery of the product was the main resilience factor. Study Limitations/Implications: Recognizing the difference between success and resilience factors can help rural enterprises, their leaders, and decision-makers in the rural sector to understand and adjust their operating strategies based on their objectives. Findings/Conclusions: A success factor is a way to stand out among similar rural enterprises, while a business resilience factor serves to face adversity and continue over time.

A new species of Andinobates (Dendrobatidae) is described from the East Andes of Colombia, just 37 km away from the Colombian capital, Bogotá. Andinobates supata sp. nov., represents the second known species of yellow Andinobates, and can be distinguished from the other, Andinobates tolimensis, by an unique combination of ventral and dorsal color patterns. Our phylogenetic analyses, based on ≈ 1120 bp from two mitochondrial markers (16S rRNA and cytochrome b) showed that this new taxon is sister to a clade formed by A. cassidyhornae, A. bombetes, A. opisthomelas, A. tolimensis and A. virolinensis. The new species appears to be restricted to a handful of small forest fragments (

Abderemane-Ali et al. investigated the mechanisms underlying self-resistance in poison dart frogs and poison birds.

Abstrac Objective: The objective of the research was to study the technological features of allspice production, to show potential areas of intervention in the crop. Methodology: The study was carried out in five of 22 producing municipalities in the state of Veracruz selected by non-probabilistic sampling; 50 surveys were applied to producers selected by the snowball method. Were data collected on the profile of the production unit and knowledge - practice of innovations. Were applied descriptive statistics; besides were calculated rates of knowledge and practice and indexes of knowledge and practice; it was made a classification of opportunity areas based on innovation diffusion theory. Results: Allspice occupies small areas and continues in a complementary role; the rates of knowledge and practice show that the categories of marketing, organization, and nutrition are the lowest; in the opposite direction are the categories of harvest, sustainable management, and agronomic management. The categories show areas of opportunity for intervention in less known and practiced innovations; as well as an opportunity for reinvention in the best-known and most practiced categories. Limitations of the study: Due to the difficult access to producer databases, it was decided to carry out a snowball sampling. Conclusion: The increase in knowledge and practice rates are determined by areas of opportunity and the rethinking of the best-known innovations. The role played by allspice, the surface area occupied, and the presence of other commercial crops may be the explanation of the productive state.

— Mesquite (Prosopis laevigata) is a tree of arid and semi-arid areas of northern and central Mexico. This species allows erosion control, atmospheric nitrogen fixation, and improves soil quality. Pseudomonas fluorescens is a rhizobacterium that favors plant growth-promoting rhizobacteria (PGPR). Also, promotes seed germination and development of Mesquite plants under adverse environmental conditions. The aim is to evaluate the role of bacterial strains A7 and Sv of P. fluorescens, using two types of soil (vertisol and phaeozem), and adding vermicompost (0, 25, 50, 75 and 100 tons/ha) in the germination and growth stages of mesquite (Prosopis laevigata).We tested the characteristics developed by the plants over 180 days. A randomized experimental design with four repetitions was used to test the seed germination rate and 16 more variables in the greenhouse, such as morphology, dry biomass accumulated, and morphological indices through the randomized factorial experimental design with three factors, 2x3x5x3. Regarding the control treatment, the use of the bacterial strain A7 of P. fluorescens inhibited the germination of mesquite seeds, while the strain Sv favored seedlings development. We observed opposite effects; inhibition and growth in the germination stage, and development of the seedlings observed at 180 days when using the A7 and Sv strains of P. fluorescens.

—The mesquite tree (Prosopis laevigata), besides its conventional uses, has a high potential to recover agricultural areas with salinity problems. It improves the physical and chemical properties of the soil, and in the rehabilitation of degraded arid and semi-arid zones, or those tending to desertification.The aim of this research was to test the effect of organic fertilization and inoculation withGlomus sp. on mesquite trees. We did the experiment under greenhouse conditions. The effect of applying Glomus sp. and organic matter in different doses during the growth of shoots and roots was evaluated in 13 agronomic variables in mesquite seedlings grown in Lithosols and Xerosols soils. We used a complete randomized block design with three replications. After 180 days, we analyzed the data using Statistical Analysis Software (SAS) version 9.2. We observed a positive and significant effect on the growth of the agronomic variables studied under greenhouse conditions, and inoculation with Glomus sp. The organic matter factor presented significant differences (p ≤ 0.05). We determined that the ideal dose was 55 g per experimental unit. According to the soil used, positive effects (p ≤ 0.05) were observed for 50% of the agronomic variables in the Xerosols soil with relation to the Lithosols soil.We concluded that the inoculation of Prosopis laevigata with Glomussp., and adding organic matter favors the growth of both the shots and the roots of the plant.

— In this study, we tested the growth of two varieties of Roselle (Hibiscus sabdariffa) cultivated in two types of soils and the effects of the inoculation of seeds with cells of bacterial strains and vermicompost. (H. sabdariffa) are a member of the Malvaceae family and an important plant because its calyxes are used to produce beverages, prepare food, in the textile industry, cosmetology, perfumery, medicine, etc. This research was carried out at the Postgraduate College, Montecillo Campus, Mexico. The experimental design was completely randomized blocks with a factorial arrangement (4x3x2): four levels of organic matter factor, three levels of bacterial strains factor, and two levels of soil factor with three repetitions. The variables tested were: germination percentage (GP), plant height (PH), stem diameter (SD), the number of leaves (NL), foliar area (FA cm2), radical volume (RV cm3), dry aerial part biomass weight (DAPBW), dry root biomass weight (DRBW), dry calyx biomass weight (DCBW) and chlorophyll content (CC). The effects of soil and bacterial strains showed significant differences (p ≤ 0.05) on the agronomic characteristics of (H. sabdariffa) plants. The organic matter factor only presented significant differences (p ≤ 0.05) in the germination percentage and growth variables of the vegetative phase. To increase crop production, the use of wastewater and microorganisms is proposed. Vermicompost exploded the percentage of germination, height, the number of leaves and stem diameter during the first weeks of growth, presenting important results in Creole variety (farmers’ local variety). By inoculating seeds with cells of bacterial strains, A9m and A7 helped significantly to stimulate plant growth, finding a better response in A9m strain. The effects of soil factor showed significant differences (p ≤ 0.05) in soil irrigated with residual water over agronomic characteristics satisfying the nutritional requirements of the crop.

Massive worldwide serological testing for SARS-CoV-2 is needed to determine the extent of virus exposure in a particular region, the ratio of symptomatic to asymptomatic infected persons, and the duration and extent of immunity after infection. To achieve this aim, the development and production of reliable and cost-effective SARS-CoV-2 antigens is critical.Here, we report the bacterial production of the peptide S-RBDN318-V510, which contains the receptor binding domain of the SARS-CoV-2 spike protein. We purified this peptide using a straightforward approach involving bacterial lysis, his-tag mediated affinity chromatography, and imidazole-assisted refolding. The antigen performances of S-RBDN318-V510 and a commercial full-length spike protein were compared in two distinct ELISAs. In direct ELISAs, where the antigen was directly bound to the ELISA surface, both antigens discriminated sera from non-exposed and exposed individuals. However, the discriminating resolution was better in ELISAs that used the full-spike antigen than the S-RBDN318-V510. Attachment of the antigens to the ELISA surface using a layer of anti-histidine antibodies gave equivalent resolution for both S-RBDN318-V510 and the full length spike protein.Our results demonstrate that ELISA-functional SARS-CoV-2 antigens can be produced in bacterial cultures. S-RBDN318-V510 is amenable to massive production and may represent a cost-effective alternative to the use of structurally more complex antigens in serological COVID-19 testing.

The geographic distribution of phenotypic variation among closely related populations is a valuable source of information about the evolutionary processes that generate and maintain biodiversity. Leapfrog distributions, in which phenotypically similar populations are disjunctly distributed and separated by phenotypically distinct populations, represent geographic replicates for the existence of a phenotype, and are therefore especially informative. These geographic patterns have mostly been studied from phylogenetic perspectives to understand how common ancestry and divergent evolution drive their formation. Other processes, such as gene flow between populations, have not received as much attention. Here we investigate the roles of divergence and gene flow between populations in the origin and maintenance of a leapfrog distribution in Phyllobates poison frogs. We found evidence for high levels of gene flow between neighboring populations but not over long distances, indicating that gene flow between central populations may have a homogenizing effect that maintains their similarity, and that introgression between "leapfroging" taxa has not played a prominent role as a driver of phenotypic diversity in Phyllobates. Although phylogenetic analyses suggest that the leapfrog distribution was formed through independent evolution of the peripheral (i.e. leapfrogging) populations, the elevated levels of gene flow between geographically close populations poise alternative scenarios, such as the history of phenotypic change becoming decoupled from genome-averaged patterns of divergence, which we cannot rule out. These results highlight the importance of incorporating gene flow between populations into the study of geographic variation in phenotypes, both as a driver of phenotypic diversity and as a confounding factor of phylogeographic inferences.

Toxicity is widespread among living organisms, and evolves as a multimodal phenotype. Part of this phenotype is the ability to avoid self-intoxication (autoresistance). Evolving toxin resistance can involve fitness tradeoffs, so autoresistance is often expected to evolve gradually and in tandem with toxicity, resulting in a correlation between the degrees of toxicity and autoresistance among toxic populations. We investigate this correlation in Phyllobates poison frogs, notorious for secreting batrachotoxin (BTX), a potent neurotoxin that targets sodium channels, using ancestral sequence reconstructions of BTX-sensing areas of the muscular voltage-gated sodium channel. Reconstructions suggest that BTX resistance arose at the root of Phyllobates, coinciding with the evolution of BTX secretion. After this event, little or no further evolution of autoresistance seems to have occurred, despite large increases in toxicity throughout the history of these frogs. Our results, therefore, provide no evidence in favor of an evolutionary correlation between toxicity and autoresistance, which conflicts with previous work. Future research on the functional costs and benefits of mutations putatively involved in BTX resistance, as well as their prevalence in natural populations, should shed light on the evolutionary mechanisms driving the relationship between toxicity and autoresistance in Phyllobates frogs.

The Ebola virus (EBOV) disease has caused serious and recurrent epidemics in recent years, resulting in a fatality rate of nearly 50%. The most effective experimental therapy against the EBOV is the use of monoclonal antibodies (mAbs). In this work, we describe the development of HEK293T cells engineered for the transient and stable expression of mAb13C6, a neutralizing anti-EBOV monoclonal antibody. We transfected the HEK293T cells with a tricistronic vector to produce the heavy and the light chain of the antibody 13C6 and intracellular Green Fluorescent Protein (GFP) using Lipofectamine 3000. We then selected the transfected cells using puromycin pressure, dilution cloning, and cloning disks. This integrated strategy generated mAb-producing cells in 7 days with a transient expression of ∼1 mg/L. Stable pools were produced after 4 weeks, with expression levels of ∼0.8 mg/L. Stable clones with expression levels of ∼1.8 mg/L were obtained within 10 weeks. The produced antibodies exhibited the expected functionality; they recognized the GP glycoprotein of the Ebola virus in both ELISA assays and cell binding experiments using HEK293T cells engineered to express the EBOV GP at their membrane surface. By the combined use of GFP and the set of selection techniques here described, we drastically reduced the time from transfection to stable clone generation without resorting to costly equipment. In outbreaks or emergencies, this platform can significantly shorten the development of new biopharmaceuticals and vaccines.

espanolEn la agricultura mexicana las unidades de produccion que predominan son las familiares, lo cual hace que la transmision de la gestion y la propiedad de estas ponga en riesgo su continuidad y competitividad. Este estudio describe los escenarios de la sucesion en tres regiones contrastantes del centro de Mexico, a partir de encuestas a productores, y genera una tipologia de productores de acuerdo con sus modalidades y perspectivas de sucesion con base en metodos multivariados. Los resultados muestran que los escenarios de sucesion prevalecientes no son planeados, bajo la expectativa de que no habra conflictos en el proceso. Se identificaron cuatro tipos de sucesion basadas en la existencia o no de un plan de sucesion y en el interes o no de continuar en la actividad agricola. Las variables mas significativas que determinan los tipos identificados son edad del productor, destino de la produccion y costo de la tierra. El tema de sucesion es poco tratado en las familias y gobiernos, sin embargo, sus implicaciones son muy importantes para el patrimonio familiar y la actividad productiva. Por ello es necesario desarrollar programas de capacitacion y asesoria a los productores sobre esta tematica EnglishIn Mexican agriculture, family farms predominate and consequently the transmission of their management and ownership affects their continuity and competitiveness. This study describes the succession scenarios in three contrasting regions of central Mexico using surveys addressed to producers and generates a producers typology according to their modalities and prospects of succession through multivariate methods. The results show that succession is not planned because there is the expectation that the process will not have any conflict. Four types of successions were identified according to the existence of a succession plan and interest of continuing in the agricultural activity. The most significant variables that explain the succession types identified are the age of the farmer, the destination of production and the cost of land. Succession is not considered by families and governments, however, its implications are important for family heritage and agricultural activity. Therefore it is necessary to develop training and advising programs to producers on this subject

Aposematism is the use of warning signals to advertise unpleasant or dangerous defences to potential predators. As the effectiveness of this strategy depends on predator learning, little variation is expected in aposematic warning signals, as similar signals facilitate predator learning. However, warning signals are frequently variable in aposematic species. Such variability could arise as a result of geographic variation in the interpretation that local predators give warning signals. We tested this divergent learning hypothesis in the polytypic poison frog Andinobates bombetes (Anura: Dendrobatidae), focusing on visual predators. Our study was conducted in two populations of this species located in the Western Andes of Colombia, where individuals at some localities exhibit red dorsolateral stripes, while those in others exhibit yellow dorsolateral stripes. We deployed paraffin models imitating both forms of A. bombetes in size and colouration, as well as dull‐coloured controls, at sites inhabited by either red‐striped or yellow‐striped frogs. Red and yellow models were attacked at similar rates at both sites, and brown models were attacked more frequently at one of the sites. These results suggest that red and yellow colourations function as similarly effective aposematic signals for primarily visual predators, regardless of the form previously experienced by these predators. Therefore, our results do not support the hypothesis of divergent predator learning as a driver of the polytypism present in this species. Finally, we discuss other mechanisms that may be involved in the evolution and maintenance of this polytypism.

Made available in DSpace on 2020-12-10T19:56:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-04-06 Proyecto Semilla de la Universidad de los Andes National Geographic Society National Science Foundation International Research Fellowship Gatorade Fund of the University of Florida Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICETArgentina) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) National Science Foundation, USA National Aeronautics and Space Administration (USA) Migratory animals move up to thousands of kilometers every year [1]. Losses of migration (i.e., migratory drop-offs) occur when individuals of a migratory species stop migrating and establish founder sedentary populations, a phenomenon documented in birds [2-5] and butterflies [6]. In theory, losses-and also gains-of migration might promote speciation if sedentary and migratory populations become reproductively isolated [7-9]. Because migratory and sedentary strategies involve alternative physiological, behavioral, and morphological traits [10-13], divergence along multiple axes of organismal function is expected to accompany switches in migratory behavior, potentially accelerating speciation. We present evidence of speciation driven by a migratory drop-off in the fork-tailed flycatcher (Tyrannus savana) resulting in reproductive isolation likely driven by changes in breeding schedules (allochronic speciation [13-15]) and geographic isolation of breeding grounds (allopatric speciation [16]). Phylogenetic analyses across New World flycatchers (Tyrannidae) showed that an association between speciation and drop-offs is also observable at a macroevolutionary scale. Loss of migration was significantly more frequent than its gain, and speciation rates of migratory and partially migratory lineages (i.e., species having both migratory and sedentary populations) exceeded those of sedentary lineages. Models of trait evolution indicated that partial migration is an intermediate step between migratory and sedentary states in this family. Given that partial migration is widespread across migratory animals (e.g., of all migratory birds, ca. 51% are partially migratory [5]), speciation via switches in migratory behavior might be an important yet overlooked mechanism of animal diversification. Univ Illinois, Dept Biol Sci, 845 West Taylor St,MC066, Chicago, IL 60607 USA Univ Andes, Dept Ciencias Biol, 1,18A-12, Bogota, Colombia Field Museum Nat Hist, 1400 South Lake Shore Dr, Chicago, IL 60605 USA SELVA Invest Conservac Neotrop, Diagonal 42A,20-37, Bogota, Colombia Univ Chicago, Dept Ecol & Evolut, 1101 East 57th St, Chicago, IL 60637 USA Univ Estadual Paulista, Inst Biociencias, Dept Zool, Ave 24A,1515, Rio Claro, SP, Brazil Univ Sao Paulo, Inst Biociencias, Dept Genet & Biol Evolut, Rua Matao,277 Butanta, BR-05508090 Sao Paulo, SP, Brazil Univ Buenos Aires, Dept Genet & Biol Evolut, Fac Ciencias Exactas & Nat, Inst IEGEBA,CONICET, Intendente Guiraldes 2160,C1428EGA, Buenos Aires, DF, Argentina Pontificia Univ Javeriana, Fac Ciencias, Dept Biol, Carrera 7,40-62, Bogota, Colombia Univ Estadual Paulista, Inst Biociencias, Dept Zool, Ave 24A,1515, Rio Claro, SP, Brazil National Geographic Society: 8444-08 National Geographic Society: 8953-11 National Science Foundation International Research Fellowship: IRFP-0965213 FAPESP: 2012/17225-2 FAPESP: 2013/19116-9 FAPESP: BIOTA 2013/50297-0 National Science Foundation, USA: DOB 1343578

Massive worldwide serological testing for SARS-CoV-2 is needed to determine the extent of virus exposure in a particular region, the ratio of symptomatic to asymptomatic infected persons, and the duration and extent of immunity after infection. To achieve this, the development and production of reliable and cost-effective SARS-CoV-2 antigens is critical. We report the bacterial production of the peptide S-RBDN318-V510, which contains the receptor-binding domain of the SARS-CoV-2 spike protein (region of 193 amino acid residues from asparagine-318 to valine-510) of the SARS-CoV-2 spike protein. We purified this peptide using a straightforward approach involving bacterial lysis, his-tag-mediated affinity chromatography, and imidazole-assisted refolding. The antigen performances of S-RBDN318-V510 and a commercial full-length spike protein were compared in ELISAs. In direct ELISAs, where the antigen was directly bound to the ELISA surface, both antigens discriminated sera from non-exposed and exposed individuals. However, the discriminating resolution was better in ELISAs that used the full-spike antigen than the S-RBDN318-V510. Attachment of the antigens to the ELISA surface using a layer of anti-histidine antibodies gave equivalent resolution for both S-RBDN318-V510 and the full-length spike protein. Results demonstrate that ELISA-functional SARS-CoV-2 antigens can be produced in bacterial cultures, and that S-RBDN318-V510 may represent a cost-effective alternative to the use of structurally more complex antigens in serological COVID-19 testing.

The development of point-of-care (POC) diagnostic systems has received well-deserved attention in recent years in the scientific literature, and many experimental systems show great promise in real settings. However, in the case of an epidemic emergency (or a natural disaster), the first line of response should be based on commercially available and validated resources. Here, we compare the performance and ease of use of the miniPCR, a recently commercially available compact and portable PCR device, and a conventional thermocycler for the diagnostics of viral nucleic acids. We used both thermocyclers to detect and amplify Ebola and Zika DNA sequences of different lengths (in the range of 91 to 300 nucleotides) at different concentrations (in the range of ~50 to 4.0 x 108 DNA copies). Our results suggest that the performance of both thermocyclers is quite similar. Moreover, the portability, ease of use, and reproducibility of the miniPCR makes it a reliable alternative for point-of-care nucleic acid detection and amplification.

Toxicity is widespread among living organisms, and evolves as a multimodal phenotype. Part of this phenotype is the ability to avoid self-intoxication (autoresistance). Evolving toxin resistance can involve fitness tradeoffs, so autoresistance is often expected to evolve gradually and in tandem with toxicity, resulting in a correlation between the degrees of toxicity and autoresistance among toxic populations. We investigate this correlation in Phyllobates poison frogs, notorious for secreting batrachotoxin (BTX), a potent neurotoxin that targets sodium channels, using ancestral sequence reconstructions of BTX–sensing areas of the muscular voltage-gated sodium channel. Reconstructions suggest that BTX resistance arose at the root of Phyllobates, coinciding with the evolution of BTX secretion. After this event little or no further evolution of autoresistance seems to have occurred, despite large increases in toxicity throughout the history of these frogs. Our results therefore provide no evidence in favor of an evolutionary correlation between toxicity and autoresistance, which conflicts with previous work. Future research on the functional costs and benefits of mutations putatively involved in BTX resistance, as well as their prevalence in natural populations should shed light on the evolutionary mechanisms driving the relationship between toxicity and autoresistance in Phyllobates frogs.

Technical and entrepreneurial training was provided for two groups of young adults to prepare them for commercial production of horticultural goods under greenhouse conditions. Most participants (90%) had only basic formal education and no experience in agriculture. Both teachings were done simultaneously. Thus, they learn how to produce based on market demands, and how to operate as a business. This educational experience resulted in a high satisfaction for the participants, and gave them the skills needed for commercial production because they were able to produce and market one harvest. Their main challenge is to develop an enterprise.

The poison frogs of the Colombian Andes, Pacific lowlands and Panamahave been recently recognized as a new, monophyletic and well-supported genus: Andinobates. The species richness and distribution within Andinobates remain poorly understood due to the paucity of geographic, genetic and phenotypic data. Here we use a combination of molecular, bioacoustic and morphometric evidence to describe a new species of Andean poison frog: Andinobates cassidyhornae sp. nov. from the high elevation cloud forests of the Colombian Cordillera Occidental, in the northwestern Andes. The new species is associated to the bombetes group and characterized by a unique combination of ventral and dorsal color patterns. Data on 1119 bp from two mitochondrial markers allowed us to reject the null hypotheses that A. cassidyhornae sp. nov. is part of the phenotypically similar and geographically less distant species: A. opisthomelas, A. virolinensis or A. bombetes. The best available phylogenetic trees and the genetic distance to other Andinobates species further support this decision. Altogether, the advertisement call parameters unambiguously separated A. cassidyhornae sp. nov. calls from the calls of the three closest species. The new species adds to a poorly known and highly endangered genus of poison frogs that requires further studies and urgent conservation measures.

The 2014 Ebola outbreak, the largest recorded, took us largely unprepared, with no available vaccine or specific treatment. In this context, the World Health Organization (WHO) declared that the humanitarian use of experimental therapies against Ebola Virus (EBOV) is ethical. In particular, an experimental treatment consisting of a cocktail of three monoclonal antibodies (mAbs) produced in tobacco plants and specifically directed to the Ebola virus glycoprotein (GP) was tested in humans, apparently with good results. Several mAbs with high affinity to the GP have been described. This review discusses our current knowledge on this topic. Particular emphasis is devoted to those mAbs that have been assayed in animal models or humans as possible therapies against Ebola. Engineering aspects and challenges for the production of anti-Ebola mAbs are also briefly discussed; current platforms for the design and production of full-length mAbs are cumbersome and costly.

Lime trees develop as shrubs, with a dense canopy and small, abundant sharp spines on all their branches. If lime trees are allowed to grow freely in deep, sandy, loam soil, with ample nutrient availability, they can reach up to 8 m tall in 12 years. Lime trees are evergreen and have functional leaves all year round. The distance between two leaves is the internode. When there is strong branch growth, internodes tend to be longer. When a terminal bud appears on a branch, thus halting new leaf production and growth of any existing ones, internodes become shorter. These are fundamental concepts that aid differentiation of the kinds of lime branches. This chapter describes the Mexican lime (C. aurantifolia [C. aurantiifolia]) branches with different types of buds and leaves, as well as the tree phenology, focusing on vegetative sprouting, flower sprouting, fruit development and maturation, and flowering management.

The salamander fauna of Colombia is very poorly known, probably because most research efforts have been devoted to anurans during the last two decades. Here, we describe two new species of the genus Bolitoglossa (Eladinea) from the eastern flank of the Eastern Colombian Andes (Cordillera Oriental), near the border with Venezuela. Bolitoglossa tamaense sp. nov. is distributed between 2000 to 2700 m.a.s.l. and Bolitoglossa leandrae sp. nov. is distributed in the low-lands at about 600 m. The new species are diagnosed by a combination of molecular (16S rRNA sequences), coloration, body size, and morphometric (number of maxillary and vomerine teeth and differences in foot webbing) characters. Both species face threats such as chytridiomycosis infections and habitat fragmentation that have already affected other sala-manders in the country. Thus, intensive field and museum work is needed to better document and perhaps protect the local salamander diversity.

Mexico produces the three most important types of lime: Mexican, Persian, andItalian. Persian lime (Citrus latifolia) is the second most important in planted area.Forty-six percent of the production is intended for export. The objective of thisresearch was to analyze the Persian lime value network of the packing andexporting companies. It was conducted at the main Persian lime producing area,located in the central coastal region of the Gulf of Mexico. As an average, thesampled companies were using 55% of their packing capacity. Most of them (83%)work all year long. They have been from 6 to 15 years in operation. Theyemployed a mean of 41 people, thus they are medium-size enterprises. Fourteenactors were complementing their business in production and marketing. Therelationship between packers and the small lime producing farmers was veryinequitable. Low prices were common for Persian lime producers.The fruits theywere packing came mainly from local producers (90%).Their main exportdestinations were: United States, Europe, Canada, and Japan. Other regions areincreasing Persian lime production, threatening the marketing of the farmers of thecentral coast of the Gulf of Mexico.

El objetivo del presente trabajo fue caracterizar el proceso productivo del nopal tunero en Axapusco, Estado de México mediante encuestas a productores y entrevistas a los actores clave. La mayoría de los productores son ejidatarios (73 %). El sistema de producción tiene una gran variabilidad. Barbechan (37 %) y subsolean (34 %) para preparar el suelo. La densidad más común es de 600 a 700 plantas por hectárea (38 %). La distancia de 4.0 m x 4.0 m es la más utilizada (55 %). La variedad cultivada predominante (74 %) es la blanca (Opuntia albicarpa). El 67 % de los productores deshierba de forma manual. El 54 % de los productores aplican estiércol fresco de vaca. La gran mayoría de los productores no reciben asesoría técnica (96 %). El 71 % de los productores declaró que no reciben ningún apoyo gubernamental. El problema más importante para los agricultores es el control de plagas y enfermedades (34 %). Le siguen los precios bajos de la tuna y el manejo de las huertas (ambos con 21 %). En ellos concurre como causa subyacente la falta de conocimiento técnico. Se requieren varias estrategias para solucionar esta problemática. Destaca realizar el composteo del estiércol, el uso de bioinsecticidas para control de insectos y mejorar la organización.

The objectives of this work were to characterize strawberry growers in Zamora, Michoacan, Mexico, and to identify factors limiting produc¬tion with the methodology of innovation networks. The state of Michoacan is the largest strawberry producer in Mexico, but production is extensive and disorganized. The productive system network of strawberry has a large number of nodes, but dispersion is high. This fact is reflected in the scarce number of links (265), a low density and an elevated standard deviation (12.47 %). The centralization index is 18.36 %, in part because decision-making and access to system information in the web are concentrated in only two actors; one of them is a final buyer and the other is a local lender. The strawberry agribusinessmen from Michoacan interviewed had a mean yield of 24.44 t•ha-1. Their per hectare income was $ 9,208 USCy, but with a cost of production of $11,867 USCy and an index of innovation adoption of 55.56 %. The adoption of organizational innovations is limited. All these factors originate low macro competitiveness. It is necessary to enhance innovation to increase the competitiveness.

Los objetivos del presente trabajo fueron caracterizar a actores productores de fresa en el municipio de Zamora, Michoacán e identificar factores restrictivos asociados a la rentabilidad y competitividad, utilizando la metodología de redes de innovación. La producción de fresa en el estado de Michoacán, principal entidad productora de fresa en México, es del tipo extensivo y se encuentra desorganizada, con un tamaño grande de nodos y alta dispersión, hecho que se refleja en el número escaso de vínculos (265), una baja densidad y un alto valor numérico en la desviación estándar (12.47 %). Su índice de centralización es de 18.36 %, que es bajo, en parte porque la toma de decisiones y el acceso a la información en la red del sistema se encuentran centralizados en sólo dos actores, uno de los cuales es un comprador final y el otro un prestamista local. Los agroempresarios freseros de Michoacán entrevistados tuvieron en promedio un rendimiento de 26.44 t.ha-1, un ingreso por hectárea de $ 110,677.84, un costo de producción de $ 142, 641.00 y un índice de adopción de innovaciones de 55.56 %. La adopción de innovaciones organizacionales también es limitada, y todo esto influye para que se tenga una competitividad nacional macro baja. Para mejorar la competitividad es indispensable empezar a trabajar la innovación, sobre todo la organizativa.

The poison frogs of the Colombian Andes, Pacific lowlands and Panama have been recently recognized as a new, monophyletic and well-supported genus: Andinobates. The species richness and distribution within Andinobates remain poorly understood due to the paucity of geographic, genetic and phenotypic data. Here we use a combination of molecular, bioacoustic and morphometric evidence to describe a new species of Andean poison frog: Andinobates cassidyhornae sp. nov. from the high elevation cloud forests of the Colombian Cordillera Occidental, in the northwestern Andes. The new species is associated to the bombetes group and characterized by a unique combination of ventral and dorsal color patterns. Data on 1119 bp from two mitochondrial markers allowed us to reject the null hypotheses that A. cassidyhornae sp. nov. is part of the phenotypically similar and geographically less distant species: A. opisthomelas, A. virolinensis or A. bombetes. The best available phylogenetic trees and the genetic distance to other Andinobates species further support this decision. Altogether, the advertisement call parameters unambiguously separated A. cassidyhornae sp. nov. calls from the calls of the three closest species. The new species adds to a poorly known and highly endangered genus of poison frogs that requires further studies and urgent conservation measures.

Background Current Ebola virus (EBOV) detection methods are costly and impractical for epidemic scenarios. Different immune-based assays have been reported for the detection and quantification of Ebola virus (EBOV) proteins. In particular, several monoclonal antibodies (mAbs) have been described that bind the capsid glycoprotein (GP) of EBOV GP. However, the currently available platforms for the design and production of full-length mAbs are cumbersome and costly. The use of antibody fragments, rather than full-length antibodies, might represent a cost-effective alternative for the development of diagnostic and possibly even therapeutic alternatives for EBOV. Methods/Principal Findings We report the design and expression of three recombinant anti-GP mAb fragments in Escherichia coli cultures. These fragments contained the heavy and light variable portions of the three well-studied anti-GP full-length mAbs 13C6, 13F6, and KZ52, and are consequently named scFv-13C6, scFv-13F6, and Fab-KZ52, respectively. All three fragments exhibited specific anti-GP binding activity in ELISA experiments comparable to that of full-length anti-GP antibodies (i.e., the same order of magnitude) and they are easily and economically produced in bacterial cultures. Conclusion/Significance Antibody fragments might represent a useful, effective, and low cost alternative to full-length antibodies in Ebola related capture and diagnostics applications., National Science Foundation (U.S.) (EFRI-1240443), IMMODGEL 602694, National Institutes of Health (U.S.) (EB012597), National Institutes of Health (U.S.) (AR057837), National Institutes of Health (U.S.) (DE021468), National Institutes of Health (U.S.) (HL099073), National Institutes of Health (U.S.) (AI105024), National Institutes of Health (U.S.) (AR063745)