Towards accurate monitoring of water content in woody tissue across tropical forests and other biomes.

Forest ecosystems face increasing drought exposure due to climate change, necessitating accurate measurements of vegetation water content to assess drought stress and tree mortality risks. Although Frequency Domain Reflectometry offers a viable method for monitoring stem water content by measuring dielectric permittivity, challenges arise from uncertainties in sensor calibration linked to wood properties and species variability, impeding its wider usage. We sampled tropical forest trees and palms in eastern Amazônia to evaluate how sensor output differences are controlled by wood density, temperature and taxonomic identity. Three individuals per species were felled and cut into segments within a diverse dataset comprising five dicotyledonous tree and three monocotyledonous palm species on a wide range of wood densities. Water content was estimated gravimetrically for each segment using a temporally explicit wet-up/dry-down approach and the relationship with the dielectric permittivity was examined. Woody tissue density had no significant impact on the calibration, but species identity and temperature significantly affected sensor readings. The temperature artefact was quantitatively important at large temperature differences, which may have led to significant bias of daily and seasonal water content dynamics in previous studies. We established the first tropical tree and palm calibration equation which performed well for estimating water content. Notably, we demonstrated that the sensitivity remained consistent across species, enabling the creation of a simplified one-slope calibration for accurate, species-independent measurements of relative water content. Our one-slope calibration serves as a general, species-independent standard calibration for assessing relative water content in woody tissue, offering a valuable tool for quantifying drought responses and stress in trees and forest ecosystems.

The Tracking of Moist Habitats Allowed Aiphanes (Arecaceae) to Cover the Elevation Gradient of the Northern Andes.

The topographic gradients of the Tropical Andes may have triggered species divergence by different mechanisms. Topography separates species' geographical ranges and offers climatic heterogeneity, which could potentially foster local adaptation to specific climatic conditions and result in narrowly distributed endemic species. Such a pattern is found in the Andean centered palm genus Aiphanes. To test the extent to which geographic barriers and climatic heterogeneity can explain distribution patterns in Aiphanes, we sampled 34 out of 36 currently recognized species in that genus and sequenced them by Sanger sequencing and/or sequence target capture sequencing. We generated Bayesian, likelihood, and species-tree phylogenies, with which we explored climatic trait evolution from current climatic occupation. We also estimated species distribution models to test the relative roles of geographical and climatic divergence in their evolution. We found that Aiphanes originated in the Miocene in Andean environments and possibly in mid-elevation habitats. Diversification is related to the occupation of the adjacent high and low elevation habitats tracking high annual precipitation and low precipitation seasonality (moist habitats). Different species in different clades repeatedly occupy all the different temperatures offered by the elevation gradient from 0 to 3,000 m in different geographically isolated areas. A pattern of conserved adaptation to moist environments is consistent among the clades. Our results stress the evolutionary roles of niche truncation of wide thermal tolerance by physical range fragmentation, coupled with water-related niche conservatism, to colonize the topographic gradient.

Methyl acetate, a highly volatile floral semiochemical mediating specialized plant-beetle interactions.

Olfactory signaling is key to the reproductive biology of entomophilous palms. Both pollinating and specialized herbivorous insects are attracted to fragrance-emitting palm inflorescences that function as reliable food sources, as well as mating and oviposition sites. In the present study, we characterized the floral scent chemistry of the acuri palm (Attalea phalerata), assessing its role in the attraction of flower-visiting insects associated with this species over its natural distribution range. We sampled insects from staminate inflorescences of A. phalerata (n = 6) at four different sites in the Brazilian Atlantic Forest and Cerrado, and Colombian Amazon basin. Dynamic headspace scent samples of both pistillate and staminate inflorescences of A. phalerata (n = 3♀, 3♂) were collected and analyzed by gas chromatography-mass spectrometry. Methyl acetate, a rare floral scent compound, was identified as the almost exclusive constituent (> 99.8% relative percentage) in all the samples. Flight-interception traps baited with methyl acetate, installed in one of the sites in the Brazilian Cerrado, were attractive to beetles associated with inflorescences of A. phalerata across all four sampling sites (9 spp. in total), including the putative main pollinators (Mystrops spp., Nitidulidae; Andranthobius spp., Curculionidae) and various palm borers (Paratenthras martinsi, Cerambycidae; Parisoschoenus sp.1 and Belopoeus sp.1; Curculionidae). Methyl acetate is highly volatile and we hypothesize its efficacy relies on profuse emission by the inflorescences of A. phalerata, as specialized pollinating insects respond to high concentrations of the attractant, perhaps before odor plumes rapidly disperse. Such a strategy could prove particularly effective in dense populations of A. phalerata.

A new species of planthopper in the genus Haplaxius/ (Hemiptera: Auchenorrhyncha: Fulgoroidea: Cixiidae) from coconut palm (Cocos/ nucifera/) in Costa Rica.

Haplaxius is a large genus of cixiid planthoppers that is widespread in the New World and economically important due to the role of H. crudus in transmitting palm lethal decline phytoplasmas. A new species of Haplaxius, here described as Haplaxius pocococo sp. n., was discovered during survey work on palms in north-central Costa Rica. Placement in Haplaxius is supported by sequence analysis of the COI and 18S genes relative to congeners and by morphological characters.

A new species of planthopper in the genus Patara (Hemiptera: Derbidae) on coconut palm (Cocos nucifera) from the island of Barbuda.

The island of Barbuda was recently surveyed for the presence of Haplaxius crudus to establish the risk of Lethal Yellowing to palms on the island. After extensive collecting, H. crudus was not found on the island. A new species of Patara Westwood was found on coconut palms on the southwest portion of Barbuda. Herein, we describe the new species as Patara cooki sp. n. and provide DNA sequence data for cytochrome c oxidase subunit I (COI) and 18S genes for it and Patara guttata Westwood. Patara cooki differed from Patara guttata sp. n. by 1.8% for 18S and 7.8% for COI, similar to intrageneric differences reported for other taxa. A phylogenetic analysis of available Otiocerinae near Patara using found Patara cooki sp. n. nested among other Patara species. We also offer commentary regarding the interpretation of forewing venation in Patara.

The occurrence of the red-handed howler monkey (Alouatta belzebul) in amazonian savannas is related to forest patch area and density of flooded area palms.

All Neotropical primates are arboreal and thus depend on forests for their survival. Arboreality puts many Neotropical primates at risk of extinction due to the high rates of deforestation in the tropics. We assessed the influence of vegetation structure and forest patch attributes on the occurrence of the threatened red-handed howler monkey (Alouatta belzebul) in an Amazonian savanna. Using a sample of 38 forest patches in a region of approximately 2000 km2 in the state of Amapá, northern Brazil, we used logistic regression to find the best predictors of the occurrence of A. belzebul. We assessed patch area, patch isolation, the proportion of seasonally flooded forest in the patch, the density of flooded area palms, forest height, canopy cover, and diameter at breast height of trees. Patch area and palm density were the best predictors of the occurrence of A. belzebul in forest patches, both having a positive effect on the probability of occurrence. Our results indicate that areas of flooded forest in forest patches may be keystone habitats for A. belzebul living in Amazonian savannas. The observed effect of palm density on A. belzebul suggests that this variable is useful for planning conservation actions, including the selection of areas for protection and management strategies for areas inhabited by this primate.

A new species of planthopper in the genus Anotia Kirby (Hemiptera: Auchenorrhyncha: Derbidae) from coconut palm in Costa Rica.

An ongoing survey for planthoppers associated with palms in the Caribbean basin is being conducted with current efforts on the Caribbean lowlands of Costa Rica. In an expedition in June of 2019, a derbid was found on coconut palms in Alajuela province and was determined to be a new species belonging to the genus Anotia. The novel taxon is described and named Anotia firebugia Bahder Bartlett sp. n. Additionally, molecular barcode data (COI) is provided for the newly described taxon.

Co-occurrence or dependence? Using spatial analyses to explore the interaction between palms and Rhodnius triatomines.

BACKGROUND: Triatomine bugs are responsible for the vectorial transmission of the parasite Trypanosoma cruzi, the etiological agent of Chagas disease, a zoonosis affecting 10 million people and with 25 million at risk of infection. Triatomines are associated with particular habitats that offer shelter and food. Several triatomine species of the genus Rhodnius have a close association with palm crowns, where bugs can obtain microclimatic stability and blood from the associated fauna. The Rhodnius-palm interaction has been reported in several places of Central and South America. However, the association in the distributions of Rhodnius species and palms has not been explicitly determined. METHODS: Niches of Rhodnius and palm species with reports of Rhodnius spp. infestation were estimated by minimum volume ellipsoids and compared in the environmental and the geographical space to identify niche similarity. Rhodnius spp. niche models were run with the palm distributions as environmental variables to determine if palm presence could be considered a predictor of Rhodnius spp. distributions, improving model performance. RESULTS: Niche similarity was found between all the studied Rhodnius and palm species showing variation in niche overlap among the involved species. Most of the areas with suitable conditions for Rhodnius species were also suitable to palm species, being favorable for more than one palm species in the majority of locations. Performance was similar in Rhodnius niche models with and without palm distributions. However, when palm distributions were included, their contribution to the model was high, being the most important variable in some Rhodnius spp. CONCLUSIONS: To our knowledge, this is the first time that the distributions of Rhodnius and palm species were compared on a large scale and their spatial association explicitly studied. We found spatial association between Rhodnius and palm species can be explained because both organisms shared environmental requirements, and most of the areas with suitable conditions for Rhodnius species were also suitable to several palm species. Rhodnius presence would not be restricted to palm presence but the zones with palm presence could be more suitable for Rhodnius spp. presence.

Deltamethrin resistance in Chagas disease vectors colonizing oil palm plantations: implications for vector control strategies in a public health-agriculture interface.

BACKGROUND: Triatomine bugs are responsible for the vectorial transmission of the parasite Trypanosoma cruzi, etiological agent of Chagas disease, a zoonosis affecting 10 million people and with 25 million at risk of infection. Several triatomine species of the genus Rhodnius have been found inhabiting palm crowns where insects can find shelter in leaves axils and blood from palm-associated vertebrates. Rhodnius prolixus insects have been collected in oil palms in Colombia, and high T. cruzi infection rates were found. Since pest control is carried out in oil palm plantations, continuous exposure to insecticides could be occurring in these triatomines. Some insecticides suggested for pest control in oil palm plantations are also recommended for triatomine control in human dwellings. In this study, our objective was to assess if triatomines inhabiting oil palms exhibit resistance to deltamethrin, an insecticide used for vector control. METHODS: Rhodnius prolixus nymphs were sampled in oil palms located in Tauramena, Colombia. To determine deltamethrin resistance, biological and biochemical assays were carried out on fifth-instar nymphs from the F1 generation. For biological assays, pure and commercial deltamethrin were used, and in biochemical assays, activities of detoxifying enzymes related to pyrethroid resistance, such as oxidases, esterases and transferases, were quantified. RESULTS: Deltamethrin lethal dosage 50 and 90 in R. prolixus from oil palms was significantly higher than in those from a susceptible colony suggesting possible deltamethrin resistance. Moreover, mortality with commercial deltamethrin was very low in insects from oil palms. In biochemical assays, the activity of evaluated detoxifying enzymes was significantly higher in R. prolixus from oil palms than in those from the susceptible colony. CONCLUSIONS: Possible deltamethrin resistance found in R. prolixus insects from oil palms could threaten traditional vector control strategies in urban settings if insecticide-resistant triatomines can migrate from oil palms plantations. In palm oil producer countries such as Colombia, the oil palm plantations are growing constantly during the last years. We suggest that pest control strategies in oil palm crops should include triatomine surveillance and toxicological monitoring, especially in zones with several Chagas disease cases.

Synopsis of the tribe Cocoseae Mart. (Arecoideae, Arecaceae) in the state of Maranhão, Brazil / Sinopse da tribo Cocoseae Mart. (Arecoideae, Arecaceae) no estado do Maranhão, Brasil

Abstract: This study presents a synopsis of the tribe Cocoseae (Arecaceae) for the Maranhão state, which was based on the descriptive analysis of voucher specimens of national and international herbaria, from loans, collection visits, digital platforms, and materials collected in expeditions. Twenty-five species belonging to seven genera were identified. The genus Bactris Jacq. ex Scop. was the most representative with seven species, followed by Attalea Kunth. (five spp.), Syagrus Mart. (five spp.), Astrocaryum G. Mey. (three spp.), Desmoncus Mart. (three spp.), Acrocomia Mart (one spp.), and Allagoptera Nees (one sp.). Four new records of occurrence were found for Maranhão: Allagoptera leucocalyx (Drude) Kuntze, Attalea barreirensis Glassman, Attalea phalerata Mart. ex Spreng. and Syagrus glazioviana (Dammer) Becc. This paper presents a taxonomic key for the species, as well as geographic distribution maps and photographic plates with the distinguishing characteristics for each taxon. Besides the taxonomic characteristics, common names, ecological data, and conservation status are included.

Resumo: Este trabalho apresenta uma sinopse da tribo Cocoseae (Arecaceae) para o estado do Maranhão, embasada na análise descritiva de amostras de herbários nacionais e internacionais, provenientes de empréstimos, visitas aos acervos e consultas em plataformas digitais, além de materiais coletados em expedições. Foram identificadas 25 espécies, pertencentes a sete gêneros. Bactris Jacq. ex Scop. foi o gênero mais representativos com sete espécies, seguido de Attalea Kunth. (cinco spp.), Syagrus Mart. (cinco spp.), Astrocaryum G. Mey. (três spp.), Desmoncus Mart. (três spp.), Acrocomia Mart. (uma spp.) e Allagoptera Nees (uma spp.). Foram encontrados quatro novos registros de ocorrência para o território maranhense: Allagoptera leucocalyx (Drude) Kuntze, Attalea barreirensis Glassman, Attalea phalerata Mart. ex Spreng. e Syagrus glazioviana (Dammer) Becc. É apresentada neste artigo uma chave taxonômica para as espécies, além de mapas de distribuição geográfica e pranchas fotográficas com características distintivas para cada táxon. São incluídos, além das características taxonômicas das espécies, nomes populares, informações ecológicas e status de conservação..

Deltamethrin resistance in Chagas disease vectors colonizing oil palm plantations: implications for vector control strategies in a public health-agriculture interface / Resistência à deltametrina em vetores da doença de Chagas que colonizam plantações de dendezeiros: implicações para estratégias de controle de vetores em uma interface saúde pública-agricultura

Background: Triatomine bugs are responsible for the vectorial transmission of the parasite Trypanosoma cruzi, etiological agent of Chagas disease, a zoonosis afecting 10 million people and with 25 million at risk of infection. Several triatomine species of the genus Rhodnius have been found inhabiting palm crowns where insects can fnd shelter in leaves axils and blood from palm-associated vertebrates. Rhodnius prolixus insects have been collected in oil palms in Colombia, and high T. cruzi infection rates were found. Since pest control is carried out in oil palm plantations, continuous exposure to insecticides could be occurring in these triatomines. Some insecticides suggested for pest control in oil palm plantations are also recommended for triatomine control in human dwellings. In this study, our objective was to assess if triatomines inhabiting oil palms exhibit resistance to deltamethrin, an insecticide used for vector control. Methods: Rhodnius prolixus nymphs were sampled in oil palms located in Tauramena, Colombia. To determine deltamethrin resistance, biological and biochemical assays were carried out on ffth-instar nymphs from the F1 generation. For biological assays, pure and commercial deltamethrin were used, and in biochemical assays, activities of detoxifying enzymes related to pyrethroid resistance, such as oxidases, esterases and transferases, were quantifed. Results: Deltamethrin lethal dosage 50 and 90 in R. prolixus from oil palms was signifcantly higher than in those from a susceptible colony suggesting possible deltamethrin resistance. Moreover, mortality with commercial deltamethrin was very low in insects from oil palms. In biochemical assays, the activity of evaluated detoxifying enzymes was signifcantly higher in R. prolixus from oil palms than in those from the susceptible colony. Conclusions: Possible deltamethrin resistance found in R. prolixus insects from oil palms could threaten traditional vector control strategies in urban settings if insecticide-resistant triatomines can migrate from oil palms plantations. In palm oil producer countries such as Colombia, the oil palm plantations are growing constantly during the last years. We suggest that pest control strategies in oil palm crops should include triatomine surveillance and toxicological monitoring, especially in zones with several Chagas disease cases

Floristic composition in ecotone forests in northern Brazilian Amazonia: preliminary data.

BACKGROUND: Ecotone has been defined as "a multi-dimensional environmentally stochastic interaction zone between ecological systems with characteristics defined in space and time, and by the strength of the interaction" (Hufkens et al. 2009). This is a known concept to define transitional zones between two or more ecological communities, ecosystems or biotic regions. Ecotone forests, dispersed in northern Brazilian Amazonia, are natural formations which have been largely affected by anthropogenic impacts, such as deforestation and fire. Maracá Ecological Station, State of Roraima, Brazil, is a protected area with extensive representations of ecotone forests in this region of the Amazonia. Forest inventories and floristic surveys are important as they extend our knowledge (1) of forest structure and tree species composition and (2) of tree and palm species ecology in this region of the Amazonia. Both improve our ability to predict changes in plant diversity, considering the future scenarios of climate change in comparison with previous surveys performed in Maracá. NEW INFORMATION: We present a forest inventory carried out in 129 plots (10 m x 50 m; 6.45 ha in total) dispersed in a grid (5 km x 5 km) located in a forest zone ecotone in the eastern part of Maracá Ecological Station. All stems (tree + palm) with diameter at breast height ≥ 10 cm were recorded, identified and measured. A total of 3040 stems were recorded (tree = 2815; palm = 225), corresponding to 42 botanic families and 140 identified species. Seven families and 20 genera contained unidentified taxa (12.2%). Sapotaceae (735 stems; 10 species), Leguminosae (409; 24) and Rubiaceae (289; 12) were the most abundant families. Peltogyne gracilipes Ducke (Leguminosae), Pradosia surinamensis (Eyma) T.D.Penn. (Sapotaceae) and Ecclinusa guianensis Eyma (Sapotaceae) were the species with the highest importance value index (~ 25%). The dominance (m2 ha-1) of these species corresponds to > 36% of the total value observed in the forest inventory. Our dataset provides complementary floristic and structure information on tree and palm in Maracá, improving our knowledge of this Amazonian ecotone forest.

Regional biogeography of microbiota composition in the Chagas disease vector Rhodnius pallescens.

BACKGROUND: Triatomine bugs are vectors of the protozoan parasite Trypanosoma cruzi, which causes Chagas disease. Rhodnius pallescens is a major vector of Chagas disease in Panama. Understanding the microbial ecology of disease vectors is important in the development of vector management strategies that target vector survival and fitness. In this study we examined the whole-body microbial composition of R. pallescens from three locations in Panama. METHODS: We collected 89 R. pallescens specimens using Noireau traps in Attalea butyracea palms. We then extracted total DNA from whole-bodies of specimens and amplified bacterial microbiota using 16S rRNA metabarcoding PCR. The 16S libraries were sequenced on an Illumina MiSeq and analyzed using QIIME2 software. RESULTS: We found Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes to be the most abundant bacterial phyla across all samples. Geographical location showed the largest difference in microbial composition with northern Veraguas Province having the most diversity and Panama Oeste Province localities being most similar to each other. Wolbachia was detected in high abundance (48-72%) at Panama Oeste area localities with a complete absence of detection in Veraguas Province. No significant differences in microbial composition were detected between triatomine age class, primary blood meal source, or T. cruzi infection status. CONCLUSIONS: We found biogeographical regions differ in microbial composition among R. pallescens populations in Panama. While overall the microbiota has bacterial taxa consistent with previous studies in triatomine microbial ecology, locality differences are an important observation for future studies. Geographical heterogeneity in microbiomes of vectors is an important consideration for future developments that leverage microbiomes for disease control.

Impact of the Mode of Extraction on the Lipidomic Profile of Oils Obtained from Selected Amazonian Fruits.

Oils and fats are important raw materials in food products, animal feed, cosmetics, and pharmaceuticals among others. The market today is dominated by oils derive, d from African palm, soybean, oilseed and animal fats. Colombia's Amazon region has endemic palms such as Euterpe precatoria (açai), Oenocarpus bataua (patawa), and Mauritia flexuosa (buriti) which grow in abundance and produce a large amount of ethereal extract. However, as these oils have never been used for any economic purpose, little is known about their chemical composition or their potential as natural ingredients for the cosmetics or food industries. In order to fill this gap, we decided to characterize the lipids present in the fruits of these palms. We began by extracting the oils using mechanical and solvent-based approaches. The oils were evaluated by quantifying the quality indices and their lipidomic profiles. The main components of these profiles were triglycerides, followed by diglycerides, fatty acids, acylcarnitine, ceramides, ergosterol, lysophosphatidylcholine, phosphatidyl ethanolamine, and sphingolipids. The results suggest that solvent extraction helped increase the diglyceride concentration in the three analyzed fruits. Unsaturated lipids were predominant in all three fruits and triolein was the most abundant compound. Characterization of the oils provides important insights into the way they might behave as potential ingredients of a range of products. The sustainable use of these oils may have considerable economic potential.

Cytological and histochemical evaluations reveal roles of the cotyledonary petiole in the germination and seedling development of Mauritia flexuosa (Arecaceae).

The cotyledonary petiole (CP) completely envelops the embryo axis during embryogenesis in Arecaceae. There is little information available, however, on the roles of that structure in seed germination and initial seedling development-crucial plant life cycle phases. The study therefore sought to evaluate the roles of CP in the germination and post-seminal development of the recalcitrant seeds of Mauritia flexuosa, an ecologically and economically important neotropical palm. The CP and the embryo/vegetative axis were evaluated during germination and initial seedling development using standard morphological, anatomical, histochemical, and ultrastructural methodologies. Evaluations of dormant seeds incubated for 60 days were also performed. The CP (a) promotes seedling protrusion in the germination, extending the embryo axis outside the seed; (b) protects the vegetative axis through the development of coating rich in phenolic compounds and lignin; (c) participates in reserve translocation, with the conversion of its own proteinaceous/mucilaginous reserves into transitional starch, as well as acting in the transport of endospermic reserves; (d) favors aeration, with the formation of pathways among stomata, substomatal chambers, and intercellular spaces; (e) controls seedling morphogenesis by modulating the curvature of the vegetative axis; and (f) contributes to overcoming seed bank dormancy through cytological alterations (protein synthesis and mitochondrial proliferation). The cotyledonary petiole of palms is a unique and multifunctional structure among angiosperms, with crucial roles in germination and seedling establishment.

A new genus and species of cixiid planthopper (Hemiptera: Auchenorrhyncha: Fulgoroidea) from the Reserva Privada el Silencio de Los Angeles Cloud Forest in Costa Rica.

Myxia belinda gen. et sp. nov. is established for a new taxon of Cixiidae in the tribe Oecleini collected from palms in Costa Rica. The new taxon was discovered while surveying palms for potential phytoplasma vectors. Placement in a new genus is supported by a 1,383 bp sequence of 18S that differs by 2.77% from Haplaxius, 5.20% from Myndus taffini, and 2.80% from Nymphomyndus caribbea. Intrageneric variation for 18S was found to be approximately 0.5% to 0.6% within Haplaxius. Generic level differences within the Oecleini for COI ranged from 15% to 17% with the novel taxon differing by about 16% from other genera. The new genus is most similar in appearance to Haplaxius but possesses striking sexual dimorphism, and the aedeagus is only partially surrounded by the phallobase (versus entirely enveloped in Haplaxius). The discovery of a novel taxon of cixiid on palms that is similar to Haplaxius is important because of the role that Haplaxius crudus plays in phytoplasma transmission in palm agro- and natural ecosystems.

[Perfil de expresión de Ki67 en lesiones melanocíticas palmoplantares: estudio de casos y controles]. / Expression profile of Ki67 in palmoplantar melanocytic lesions: a case-control study.

INTRODUCCIÓN: El melanoma acral lentiginoso es una neoplasia maligna que afecta a población predominantemente no caucásica. Debido al diagnóstico tardío suele tener mal pronóstico, además de que se considera una neoplasia biológicamente más agresiva, incluso cuando se detecta tempranamente. OBJETIVO: Determinar la expresión de Ki67 en el melanoma acral lentiginoso invasor y compararla con los nevos acrales. MÉTODO: Estudio transversal, descriptivo, observacional. Se realizó inmunohistoquímica con marcador Ki67 en 17 biopsias de melanoma acral lentiginoso invasor (casos) y 17 biopsias de nevos palmoplantares (controles). Se determinó la expresión nuclear de Ki-67 y se comparó entre ambos grupos. RESULTADOS: La media de expresión de Ki67 fue del 8.5% en el grupo control y del 34% en el grupo de melanomas, siendo esta diferencia estadísticamente significativa (p < 0.0001). DISCUSIÓN: La expresión de Ki67 en los melanomas acrales es considerablemente mayor que en los nevos acrales. El valor pronóstico del marcador Ki67 sigue siendo considerado controversial. Sin embargo, hay estudios en los que en combinación con otros marcadores se refuerza su valor pronóstico. CONCLUSIONES: Por la gran diferencia en inmunorreactividad de Ki67 entre melanomas y nevos, la expresión de Ki67, referida como índice proliferativo, podría ser considerada como factor pronóstico incluso más objetivo que el índice mitótico. BACKGROUND: Acral lentiginous melanoma is a malignant neoplasm which appears in hands and feet. Acral lentiginous melanoma has an unclear etiology, and usually affects non-Caucasian population. Because it is frequently diagnosed lately, acral melanoma has bad prognosis; however, it is biologically more aggressive than other clinicopathological types of melanoma, even when diagnosed early. OBJECTIVE: To determine the expression of Ki67 in invasive lentiginous acral melanoma and to compare it with acral nevi. METHOD: Cross-sectional, descriptive, observational study. Immunohistochemistry with Ki67 marker was performed on 17 biopsies of invasive lentiginous acral melanoma (cases) and 17 biopsies of palmoplantar nevi (controls). Nuclear expression of Ki-67 was determined and both were compared between both groups. RESULTS: The mean expression of Ki67 was 8.5% in the control group, and 34% in the melanoma group, which was statistically significant (p < 0.0001). DISCUSSION: Ki67 expression in acral lentiginous melanomas is higher than in acral nevi. Prognostic value of Ki67 is still considered controversial. However, there are several studies where, in combination with other markers, their prognostic value is reinforced. CONCLUSIONS: Due to the wide gap in Ki67 expression between melanomas and nevi showed in this study, Ki67 expression, referred to as a proliferative index, could be considered as a prognostic factor even more objective than the mitotic index.

Psoriasis pustulosa palmar unilateral: A propósito de un caso / Unilateral palmar pustular psoriasis: A clinical case

La psoriasis pustulosa palmoplantar (PPP) es una enfermedad inflamatoria crónica y recurrente, caracterizada por la presencia de pústulas estériles, sobre una base eritematosa en palmas y plantas. Es de gran importancia, debido a que ocasiona tanto limitación funcional como disminución en la calidad de vida, siendo en la mayoría de los casos refractaria al tratamiento. Se presenta un caso de PPP, donde fueron necesarias aplicar terapias combinadas: tópica y sistémica (esteroides de alta potencia y ciclosporina), con evolución satisfactoria en cuatro semanas de tratamiento. Se realizó una revisión exhaustiva en los motores de búsqueda como: Latindex.org, Scielo.org y Google académico, de las publicaciones más representativas hasta la actualidad y las palabras clave, a través de la web de Medical Subject Headings.

Palmoplantar Pustular Psoriasis (PPP) is a chronic and recurrent inflammatory disease, characterized by the presence of sterile pustules on an erythematous base in palms and soles. It is important because it causes both functional limitation decreasing quality of life. In most cases refractory to treatment. We present a case of PPP with topical and systemic combined therapy (high potency corticoids and cyclosporine) with satisfactory outcomes at four weeks of treatment. An exhaustive review in search engines as Scholar Google, Latindex and Scielo was made for the last 30 years and key words in Medical Subject Headings.

Molecular genetic analysis of two native desert palm genera, Washingtonia and Brahea, from the Baja California Peninsula and Guadalupe Island.

The complex geological and ecological processes that have generated high levels of biodiversity and endemism in the Baja California Peninsula have been the subject of intensive study. However, relatively little is known about phylogeography of the iconic endemic palm species of this region. We therefore analyzed a total of 2,294 bp of chloroplast and 738 bp of nuclear sequence data in 169 samples of five native palm species from Baja California, Sonora and Guadalupe Island. We found that Washingtonia and Brahea palms had low levels of genetic diversity and were highly structured, with the majority of species and major geographic regions being characterized by distinct haplotypes. We also found strong support for currently recognized species in Washingtonia, but our results were less clear cut for Brahea due to haplotype sharing. Furthermore, patterns of population structure were broadly consistent with historical vicariant events such as the inundation of the Isthmus of La Paz, the formation of the Sea of Cortez, and the more recent colonization and isolation of Guadalupe Island's palms. Our findings contribute toward a growing appreciation of the complexity of plant responses to past geological changes and also provide valuable baseline genetic data on relict American palm species.

Structural diversity of alkali-soluble polysaccharides from the fruit cell walls of tucumã (Astrocaryum aculeatum), a commelinid monocotyledon from the family Arecaceae.

The polysaccharide compositions of primary and secondary cell walls of members of the family Arecaceae in the commelinid clade of monocotyledonous plants have previously been found to be distinguishable from other commelinid families, and to be more similar to those of non-commelinids. However, few studies have been conducted. We aimed to extract and characterize the main cell-wall polysaccharides in the fruit pulp of tucumã (Astrocaryum aculeatum), a member of Arecaceae family. Hemicellulosic polysaccharides extracted by alkali from the fruit pulp were present in greater proportions (6.4% yield) than water-extracted ones (3.0% yield). Thus, the former was analyzed using monosaccharide composition, methylation, molecular weight determination and 13C-NMR data. The tucumã alkaline extract presented a highly ramified acidic galactoarabinoxylan (53.7%), a linear (1 â†’ 5)-linked α-L-arabinan (27.8%), a low branched glucuronoxylan (14.1%) and small portions of a xyloglucan (4.4%). The major polysaccharide found in A. aculeatum (acidic galactoarabinoxylan) is similar to those found in other commelinid plants such as grasses and cereals.