RESUMO
Members of the Leptodactylus mystaceus species complex are widely distributed in forests and open formations of South America east of the Andes. Species of the complex are morphologically similar or indistinguishable among each other, but acoustic data have been the cornerstone for species discrimination across their geographic ranges. In this paper, we re-examine the monophyly, species diversity, and relationships in the L. mystaceus complex on the basis of morphology, coloration, acoustics, and DNA sequences. Morphological and color patterns originally used to the allocation of species to the L. mystaceus complex are also reassessed. Our results revealed three new species from the Brazilian Atlantic Forest and Cerrado, which are named and described herein, based mainly on acoustic and molecular data. Populations assigned to the lineage widely distributed across the South American Dry Diagonal (DD), reported in this study as L. cf. mystaceus, is likely paraphyletic with respect to the nominal species (Amazonian lineage), but additional data are still needed to address the taxonomic status of the DD lineage.
Assuntos
Anuros , Florestas , Acústica , Animais , Brasil , FilogeniaRESUMO
We describe a new species of Physalaemus assigned to the Physalaemus signifer Clade, and it is morphologically similar to P. rupestris, from the highlands of the Serra do Cipó in the southern Espinhaço Range, State of Minas Gerais, Southeastern Brazil. The new species is diagnosed by using the following combination of character states: presence of an arrow-shaped blotch on the dorsum of body; presence of a median longitudinal light stripe over urostyle region; belly and ventral surface of thigh marbled with dark gray irregularly shaped blotches on a bluish background; absence of reddish coloration over axillary and inguinal regions in live individuals; bright orange dots scattered over head, upper lip, and dorsum of body in live individuals; ventral surface of hand and foot red in live individuals; small size (adult male SVL=16.2-18.2 mm); presence of brown, not divided, nuptial pad in males; END/ED in males ranging from 0.85-0.93; supernumerary tubercles on foot absent; tarsal fold absent; tarsal tubercle absent; texture of posterior region of belly and ventral surface of thigh smooth; advertisement call composed of two note types (note A + B); advertisement call duration of 0.80-1.28 s; note A with ascending amplitude until mid-note then descending towards the end of the note; note B with pulses arranged in 5-7 groups; and dominant frequency of note A from 1734.4-2765.6 Hz and of note B from 1507.3-2859.4 Hz. A phylogenetic analysis based on mitochondrial DNA sequences recovered the new species nested within the Physalaemus deimaticus species group. Additionally, we redescribe the call of Physalaemus rupestris and provide a review of the geographic distribution and conservation status of the species belonging to the P. deimaticus species group.
Assuntos
Anuros , Animais , Brasil , Masculino , FilogeniaRESUMO
Amyotrophic lateral sclerosis type 8 (ALS8) is an autosomal dominant form of ALS, which is caused by pathogenic variants in the VAPB gene. Here we investigated five ALS8 patients, classified as 'severe' and 'mild' from a gigantic Brazilian kindred, carrying the same VAPB mutation but displaying different clinical courses. Copy number variation and whole exome sequencing analyses in such individuals ruled out previously described genetic modifiers of pathogenicity. After deriving induced pluripotent stem cells (iPSCs) for each patient (N = 5) and controls (N = 3), motor neurons were differentiated, and high-throughput RNA-Seq gene expression measurements were performed. Functional cell death and oxidative metabolism assays were also carried out in patients' iPSC-derived motor neurons. The degree of cell death and mitochondrial oxidative metabolism were similar in iPSC-derived motor neurons from mild patients and controls and were distinct from those of severe patients. Similar findings were obtained when RNA-Seq from such cells was performed. Overall, 43 genes were upregulated and 66 downregulated in the two mild ALS8 patients when compared with severe ALS8 individuals and controls. Interestingly, significantly enriched pathways found among differentially expressed genes, such as protein translation and protein targeting to the endoplasmic reticulum (ER), are known to be associated with neurodegenerative processes. Taken together, the mitigating mechanisms here presented appear to maintain motor neuron survival by keeping translational activity and protein targeting to the ER in such cells. As ALS8 physiopathology has been associated with proteostasis mechanisms in ER-mitochondria contact sites, such differentially expressed genes appear to relate to the bypass of VAPB deficiency.
Assuntos
Esclerose Lateral Amiotrófica/genética , Mitocôndrias/genética , Degeneração Neural/genética , Proteínas de Transporte Vesicular/genética , Idoso , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Diferenciação Celular/genética , Retículo Endoplasmático/genética , Feminino , Regulação da Expressão Gênica/genética , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/patologia , Masculino , Pessoa de Meia-Idade , Mitocôndrias/metabolismo , Neurônios Motores/metabolismo , Neurônios Motores/patologia , Degeneração Neural/patologia , Estresse Oxidativo/genética , RNA-Seq , Proteínas de Transporte Vesicular/deficiênciaRESUMO
Amyotrophic Lateral Sclerosis type 8 (ALS8) is an autosomal dominant form of ALS, which is caused by pathogenic variants in the VAPB gene. Here we investigated five ALS8 patients, classified as ‘severe’ and ‘mild’ from a gigantic Brazilian kindred, carrying the same VAPB mutation but displaying different clinical courses. Copy Number Variation (CNV) and Whole Exome Sequencing (WES) analyses in such individuals ruled out previously described genetic modifiers of pathogenicity. After deriving induced pluripotent stem cells (iPSCs) for each patient (N=5) and controls (N=3), motor neurons were differentiated, and high-throughput RNA-Seq gene expression measurements were performed. Functional cell death and oxidative metabolism assays were also carried out in patients’ iPSC-derived motor neurons. The degree of cell death and mitochondrial oxidative metabolism were similar in iPSC-derived motor neurons from mild patients and controls, and were distinct from those of severe patients. Similar findings were obtained when RNA-Seq from such cells was performed. Overall, 43 genes were upregulated and 66 downregulated in the two mild ALS8 patients when compared with severe ALS8 individuals and controls. Interestingly, significantly enriched pathways found among differentially expressed genes, such as protein translation and protein targeting to endoplasmic reticulum (ER), are known to be associated with neurodegenerative processes. Taken together, the mitigating mechanisms here presented appear to maintain motor neuron survival by keeping translational activity and protein targeting to ER in such cells. As ALS8 physiopathology has been associated with proteostasis mechanisms in ER–mitochondria contact sites, such differentially expressed genes appear to relate to the bypass of VAPB deficiency.
RESUMO
The Brazilian Atlantic coastal forest is one of the most heterogeneous morphoclimatic domains on earth and is thus an excellent region in which to examine the role that habitat heterogeneity plays in shaping diversification of lineages and species. Here we present a molecular phylogeny of the rock frogs of the genus Thoropa Cope, 1865, native to the Atlantic forest and extending to adjacent campo rupestre of Brazil. The goal of this study is to reconstruct the evolutionary history of the genus using multilocus molecular phylogenetic analyses. Our topology reveals 12 highly supported lineages among the four nominal species included in the study. Species T. saxatilis and T. megatympanum are monophyletic. Thoropa taophora is also monophyletic, but nested within T. miliaris. Populations of T. miliaris cluster in five geographically distinct lineages, with low support for relationships among them. Although all 12 lineages are geographically structured, some T. miliaris lineages have syntopic distributions with others, likely reflecting a secondary contact zone between divergent lineages. We discuss a biogeographic scenario that best explains the order of divergence and the distribution of species in Atlantic forest and adjacent areas, and outline the implications of our findings for the taxonomy of Thoropa.
Assuntos
Filogenia , Ranidae/classificação , Animais , Teorema de Bayes , Brasil , DNA Mitocondrial/química , DNA Mitocondrial/isolamento & purificação , DNA Mitocondrial/metabolismo , Ecossistema , Florestas , Variação Genética , Ranidae/genética , Análise de Sequência de DNARESUMO
Amphibian population declines are widespread; the main causal factors are human related and include habitat fragmentation due to agriculture, mining, fires, and urban development. Brazil is the richest country in species of amphibians, and the Brazilian regions with the greatest amphibian diversity are experiencing relatively high rates of habitat destruction, but there are presently relatively few reports of amphibian declines. It is thus important to develop research methods that will detect deterioration in population health before severe declines occur. We tested the use of measurements of fluctuating asymmetry (FA) taken on amphibian larvae to detect anthropogenic stress. We hypothesized that greater human occupancy in the landscape might result in more stressful conditions for amphibians. We conducted this study at the Espinhaço mountain range in southeastern Brazil, using as a model an endemic species (Bokermannohyla saxicola, Hylidae). We chose two tadpole denticle rows and eye-nostril distance as traits for FA measurement. We measured percent cover of human-altered habitats in the landscape around tadpole sampling points and measured FA levels in sampled tadpoles. We found FA levels to differ among localities but found no relationship between human modification of the landscape and tadpole FA levels. Levels of FA in the traits we examined may not be strongly affected by environmental conditions, or may be affected by local variables that were not captured by our landscape-scale measures. Alternatively, populations may be genetically differentiated, affecting how FA levels respond to stress and obscuring the effects of anthropogenic disturbance.
Assuntos
Anfíbios/fisiologia , Ecossistema , Espécies em Perigo de Extinção , Estresse Fisiológico , Anfíbios/crescimento & desenvolvimento , Animais , Humanos , Larva/crescimento & desenvolvimento , Densidade DemográficaRESUMO
Bokermannohyla juiju is a member of the B. martinsi species group and it was described based on one male specimen. In order to enhance the knowledge about the species, we describe its advertisement call and morphological variation, including for the first time data on females. We also provide additional comments about its natural history, geographic distribution, and conservation. The advertisement call of B. juiju consists of a single note, non-pulsed, harmonic structured call emitted several times in a row. Four out of five males were found calling in bromeliads. The female, as it is common in many Bokermannohyla species, presents some morphological features not shared with the males, like a non-hypertrophied forearm and less developed prepollex.
Assuntos
Anuros/crescimento & desenvolvimento , Anuros/fisiologia , Vocalização Animal , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Anuros/anatomia & histologia , Anuros/classificação , Tamanho Corporal , Brasil , Ecossistema , Feminino , Masculino , Tamanho do ÓrgãoRESUMO
The genus Crossodactylodes comprises three species of Atlantic Rainforest endemic frogs strictly dependent on bromeliads where they spend their entire life cycle. The current geographic distribution of the genus covers highland areas of Atlantic Rainforest in the States of Rio de Janeiro and Espírito Santo, Southeastern Brazil. We describe a new species of the genus from Parque Estadual do Pico do Itambé, at Santo Antônio do Itambé municipality, State of Minas Gerais, Southeastern Brazil. Crossodactylodes itambe sp. nov. is characterized by the following combination of traits: male SVL 16.2 ± 1.3 (14.0-17.6 mm, n = 10), female SVL 16.2 ± 1.0 (13.5-18.0 mm, n = 15); snout short, rounded in dorsal view, sloping in lateral view; absence of vocal sac and vocal slits in males; absence of vomerine teeth; males with upper arms and forearms hypertrophied; cloacal flap prominent, simple; dorsal skin coarsely granular. The new species inhabits rupicolous bromeliads in open areas of rocky fields, and is recorded in altitudes between 1836 and 2062 m above sea level. This record extends the genus distribution for about 325 km northwest from where it was known. Crossodactylodes sp. nov. is the only species of the genus that occurs in open field habitats (campos rupestres), in very high altitudes of a non-costal mountain range (the Espinhaço Range).
Assuntos
Anuros/anatomia & histologia , Anuros/classificação , Animais , Anuros/fisiologia , Brasil , Demografia , Feminino , Masculino , Especificidade da EspécieRESUMO
The systematic investigation of the peptidic composition of the skin secretion of Phasmahyla jandaia, a phyllomedusine anuran endemic to the southern region of the Espinhaço range in Brazil, is herein reported. By means of de novo interpretation of tandem mass spectrometric data, Edman N-terminal sequencing and similarity searches, 57 peptides - including phylloseptins, dermaseptins stricto sensu, dermatoxins, hyposins, tryptophyllins, caerulein-related, bradykinin-related, bradykinin potentiating, tyrosine-rich, and opioid peptides - were sequenced. Moreover, five peptide families without significant similarity to other known molecules were verified. Differently from most Phyllomedusinae genera, the molecular diversity in the skin of representatives of Phasmahyla remained unprospected until now. Therefore, besides disclosing novel natural variants of number of bioactive peptides, the present study contributes to the understanding of the evolution of biochemical characters of the phyllomedusines.