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1.
PLoS One ; 15(7): e0235985, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32678865

RESUMO

Chronic constipation (CC) is one of the most common gastrointestinal disorders worldwide. Its pathogenesis, however, remains largely unclear. The purpose of the present work was to gain an insight into the role of contractility and microbiota in the etiology of CC. To this end, we studied spontaneous and evoked contractile activity of descending colon segments from patients that have undergone surgery for refractory forms of CC. The juxta-mucosal microbiota of these colon samples were characterized with culture-based and 16S rRNA sequencing techniques. In patients with CC the spontaneous colonic motility remained unchanged compared to the control group without dysfunction of intestinal motility. Moreover, contractions induced by potassium chloride and carbachol were increased in both circular and longitudinal colonic muscle strips, thus indicating preservation of contractile apparatus and increased sensitivity to cholinergic nerve stimulation in the constipated intestine. In the test group, the gut microbiota composition was assessed as being typically human, with four dominant bacterial phyla, namely Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria, as well as usual representation of the most prevalent gut bacterial genera. Yet, significant inter-individual differences were revealed. The phylogenetic diversity of gut microbiota was not affected by age, sex, or colonic anatomy (dolichocolon, megacolon). The abundance of butyrate-producing genera Roseburia, Coprococcus, and Faecalibacterium was low, whereas conventional probiotic genera Lactobacillus and Bifidobacteria were not decreased in the gut microbiomes of the constipated patients. As evidenced by our study, specific microbial biomarkers for constipation state are absent. The results point to a probable role played by the overall gut microbiota at the functional level. To our knowledge, this is the first comprehensive characterization of CC pathogenesis, finding lack of disruption of motor activity of colonic smooth muscle cells and insufficiency of particular members of gut microbiota usually implicated in CC.


Assuntos
Colo/microbiologia , Colo/fisiopatologia , Constipação Intestinal/microbiologia , Constipação Intestinal/fisiopatologia , Microbioma Gastrointestinal , Contração Muscular , Adulto , Idoso , Doença Crônica , Classificação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
2.
BMC Evol Biol ; 20(1): 92, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32727367

RESUMO

BACKGROUND: Hypotrichia are a group with the most complex morphology and morphogenesis within the ciliated protists. The classification of Gastrostyla-like species, a taxonomically difficult group of hypotrichs with a common ventral cirral pattern but various dorsal and ontogenetic patterns, is poorly understood. Hence, systematic relationships within this group and with other taxa in the subclass Hypotrichia remain unresolved. RESULTS: 18S rRNA gene sequence of a new Gastrostyla-like taxon was obtained. Phylogenetic analyses based on the 18S rRNA gene sequences indicate that this ciliate represents a new genus that is closely related to Heterourosomoida and Kleinstyla within the oxytrichid clade of the Hypotrichia. However, the position of this cluster remains unresolved. All three genera deviate from the typical oxytrichids by their incomplete (or lack of) dorsal kinety fragmentation during morphogenesis. Morphology and morphogenesis of this newly discovered form, Heterogastrostyla salina nov. gen., nov. spec., are described. Heterogastrostyla nov. gen., is characterised as follows: more than 18 fronto-ventral-transverse cirri, cirral anlagen V and VI develop pretransverse cirri, and dorsal ciliature in Urosomoida-like pattern. CONCLUSIONS: Similar to the CEUU-hypothesis about convergent evolution of urostylids and uroleptids, we speculate that the shared ventral cirral patterns of Gastrostyla-like taxa might have resulted from convergent evolution.


Assuntos
Cilióforos/classificação , Classificação , Salinidade , Solo , Animais , Sequência de Bases , Núcleo Celular/genética , DNA Ribossômico/genética , Hypotrichida/classificação , Hypotrichida/genética , Funções Verossimilhança , Morfogênese/genética , Filogenia , Subunidades Ribossômicas Menores/genética , Especificidade da Espécie
3.
PLoS One ; 15(7): e0233602, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32639958

RESUMO

Commonly used measures of population aging categorize adults into those who are "old" and those who are not. How this threshold of the stage of "old age" is determined is crucial for our understanding of population aging. We propose that the old age threshold be determined using an equivalency criterion. People at the old age threshold should be roughly equivalent to one another in relevant characteristics regardless of when and where they lived. The UN publishes two variants of the potential support ratio based on different old age thresholds. One old age threshold is based on a fixed chronological age and the other on a fixed remaining life expectancy. Using historical data on 5-year death rates at the old age threshold as an indicator of one aspect of health, we assess the extent to which the two approaches are consistent with the equivalency criterion. The death rates are derived from all the complete cohort life tables in the Human Mortality Database. We show that the old age threshold based on a fixed remaining life expectancy is consistent with the equivalency criterion, while the old age threshold based on a fixed chronological age is not. The picture of population aging that emerges when measures consistent with the equivalency criterion are used are markedly different from those that result when the equivalency criterion is violated. We recommend that measures of aging that violate the equivalency criterion should only be used in special circumstances where that violation is unimportant.


Assuntos
Idoso/estatística & dados numéricos , Dinâmica Populacional , Envelhecimento , Classificação , Humanos , Expectativa de Vida , Pessoa de Meia-Idade , Mortalidade , Estudos Prospectivos , Nações Unidas
4.
PLoS Biol ; 18(7): e3000736, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32634138

RESUMO

Lists of species underpin many fields of human endeavour, but there are currently no universally accepted principles for deciding which biological species should be accepted when there are alternative taxonomic treatments (and, by extension, which scientific names should be applied to those species). As improvements in information technology make it easier to communicate, access, and aggregate biodiversity information, there is a need for a framework that helps taxonomists and the users of taxonomy decide which taxa and names should be used by society whilst continuing to encourage taxonomic research that leads to new species discoveries, new knowledge of species relationships, and the refinement of existing species concepts. Here, we present 10 principles that can underpin such a governance framework, namely (i) the species list must be based on science and free from nontaxonomic considerations and interference, (ii) governance of the species list must aim for community support and use, (iii) all decisions about list composition must be transparent, (iv) the governance of validated lists of species is separate from the governance of the names of taxa, (v) governance of lists of accepted species must not constrain academic freedom, (vi) the set of criteria considered sufficient to recognise species boundaries may appropriately vary between different taxonomic groups but should be consistent when possible, (vii) a global list must balance conflicting needs for currency and stability by having archived versions, (viii) contributors need appropriate recognition, (ix) list content should be traceable, and (x) a global listing process needs both to encompass global diversity and to accommodate local knowledge of that diversity. We conclude by outlining issues that must be resolved if such a system of taxonomic list governance and a unified list of accepted scientific names generated are to be universally adopted.


Assuntos
Classificação , Biodiversidade , Tomada de Decisões , Conhecimento , Reprodutibilidade dos Testes , Especificidade da Espécie
5.
PLoS One ; 15(6): e0234627, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32530960

RESUMO

Cuscuta (dodders) is a group of parasitic plants with tremendous economic and ecological significance. Their seeds are often described as "simple" or "unspecialized" because they do not exhibit any classical dispersal syndrome traits. Previous studies of seed morphology and/or anatomy were conducted on relatively few species. We expanded research to 101 species; reconstructed ancestral character states; investigated correlations among seed characters and explored allometric relationships with breeding systems, the size of geographical distribution of species in North America, as well as the survival of seedlings. Seed morphological and anatomical characters permit the separation of subgenera, but not of sections. Identification of Cuscuta species using seed characteristics is difficult but not impossible if their geographical origin is known. Seeds of subg. Monogynella species, exhibit the likely ancestral epidermis type consisting of elongated and interlocked cells, which are morphologically invariant, uninfluenced by dryness/wetness. Subgenera Cuscuta, Pachystigma and Grammica have evolved a seed epidermis with isodiametric cells that can alternate their morphology between two states: pitted when seeds are dry, and papillose after seed imbibition. A seed coat with double palisade architecture throughout the entire seed has also apparently evolved in subgenera Cuscuta, Pachystigma and Grammica, but several species in two clades of the latter subgenus reverted to a single palisade layer outside the hilum area. The same latter species also evolved a peculiar, globose embryo, likely having a storage role, in contrast to the ancestral filiform and coiled embryo present throughout the remainder of the genus. Autogamous species had on average the highest number of seeds per capsule, whereas fully xenogamous taxa had the lowest. No correlation was revealed between the size of the seeds and the size of their geographical distribution in North America, but seedlings of species with larger seeds survived significantly longer than seedlings resulted from smaller seeds. Diversity and evolution of seed traits was discussed in relationship with their putative roles in dormancy, germination and dispersal.


Assuntos
Biodiversidade , Evolução Biológica , Classificação , Cuscuta/anatomia & histologia , Cuscuta/classificação , Sementes/anatomia & histologia , Análise de Variância , Estimativa de Kaplan-Meier , Tamanho do Órgão , Filogenia , Melhoramento Vegetal , Análise de Regressão , Plântula/anatomia & histologia , Sementes/ultraestrutura
6.
Proc Biol Sci ; 287(1929): 20200683, 2020 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-32546096

RESUMO

There are currently four world bird lists referenced by different stakeholders including governments, academic journals, museums and citizen scientists. Consolidation of these lists is a conservation and research priority. In reconciling lists, care must be taken to ensure agreement in taxonomic concepts-the actual groups of individual organisms circumscribed by a given scientific epithet. Here, we compare species-level taxonomic concepts for raptors across the four lists, highlighting areas of disagreement. Of the 665 species-level raptor taxa observed at least once among the four lists, only 453 (68%) were consistent across all four lists. The Howard and Moore Checklist of the Birds of the World contains the fewest raptor species (528), whereas the International Ornithological Community World Bird List contains the most (580) and these two lists are in the most disagreement. Of the disagreements, 67% involved owls, and Indonesia was the country containing the most disagreed upon species (169). Finally, we calculated the amount of species-level agreement across lists for each avian order and found raptor orders spread throughout the rankings of agreement. Our results emphasize the need to reconcile the four world bird lists for all avian orders, highlight broad disagreements across lists and identify hotspots of disagreement for raptors, in particular.


Assuntos
Aves Predatórias/classificação , Animais , Classificação
7.
Stud Health Technol Inform ; 270: 242-246, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32570383

RESUMO

As widely known, regular accuracy is a misleading and shallow indicator of the performance of a predictive model, especially in real-life domains like medicine, where decisions affect health or life. In this paper we present and discuss a new accuracy measure, the H-accuracy, as a more conservative alternative to regular accuracy, which we claim is more informative in the medical domain (and others of similar needs) for the elements it encompasses. In particular, the proposed measure takes into account important information such as the complexity of the cases and the case prevalance in the population. We also provide proof that the H-accuracy is a generalization of the balanced accuracy and illustrate the descriptive power of this score.


Assuntos
Inteligência Artificial , Confiabilidade dos Dados , Medicina/classificação , Classificação , Humanos
8.
Stud Health Technol Inform ; 270: 257-261, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32570386

RESUMO

Classification systems are widely used in medicine for knowledge representation. The hierarchical relationships between concepts in a classification system can be exploited in prediction models by looking for the optimal predictive granularity level. In this study, we used the Anatomical Therapeutic Chemical (ATC) classification system to cluster medications in the context of predicting medication-related falls in older persons. We compared the performance of fall risk prediction by describing medications at varying granularity levels of the ATC classification system. We found that the level of abstraction significantly affects the predictive performance in terms of both discrimination (measured by the receiver operating characteristic curve AUC-ROC) and calibration. An implication of these findings to the researchers is that data representation at different granularity levels can influence the predictive performance. The optimal granularity level can be determined by experimentation.


Assuntos
Acidentes por Quedas/prevenção & controle , Classificação , Medição de Risco/métodos , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Curva ROC , Reprodutibilidade dos Testes
9.
Rev Bras Parasitol Vet ; 29(2): e018819, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32428180

RESUMO

The cheyletid mites that parasitize mammals have been neglected for a long time in Brazil, although they can be common on pets and cause injury to their hosts. Recently, Cheyletiella parasitivorax was found parasitizing a rabbit in Brazil which represents a new host and distribution record for the mite species. An illustrated dichotomous key for the identification of the species in this genus and data from the literature are provided.


Assuntos
Animais Domésticos/parasitologia , Infestações por Ácaros/diagnóstico , Ácaros/classificação , Distribuição Animal , Animais , Brasil , Classificação/métodos , Feminino , Masculino , Infestações por Ácaros/parasitologia , Infestações por Ácaros/veterinária , Ácaros/anatomia & histologia , Coelhos/parasitologia , Especificidade da Espécie
10.
PLoS One ; 15(5): e0221607, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32469903

RESUMO

The genus Rubus L. (Rosaceae) not been investigated satisfactorily in terms of palynology. This genus is taxonomically very difficult due to the large number of species and problems with their delimitation, as well as very different distribution areas of particular species. The aim of this study was to investigate pollen morphology and for the first time the ranges of intrageneric and interspecific variability of Rubus species, as well as verify the taxonomic usefulness of these traits in distinguishing studied taxa from this genus. The selected species of the genus Rubus were analysed for 11 quantitative pollen characteristics and the following qualitative ones: exine ornamentation, pollen outline and shape, as well as bridge structure. Analyses were conducted on a total of 1740 pollen grains, which represent 58 blackberry species belonging to a majority of subgenera and all the sections and series found in Poland. The most important characters included exine ornamentation (exine ornamentation type, width and direction of grooves and striae, number and diameter of perforations) and length of the polar axis (P). The arrangement of the examined species on the dendrogram does not corroborate division of the genus Rubus into subgenera, sections and series currently adopted in taxonomy. This fact is not surprising because the taxonomy of the genus was not based on pollen characters. Pollen features should be treated in taxonomy as auxiliary, because they fail to differentiate several (10) individual species, while the other ones create groups with similar pollen traits.


Assuntos
Classificação , Pólen/ultraestrutura , Rubus/ultraestrutura , Microscopia Eletrônica de Varredura , Polônia , Pólen/classificação , Rubus/classificação , Especificidade da Espécie
11.
BMC Bioinformatics ; 21(1): 185, 2020 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-32397982

RESUMO

BACKGROUND: Microorganisms are important occupants of many different environments. Identifying the composition of microbes and estimating their abundance promote understanding of interactions of microbes in environmental samples. To understand their environments more deeply, the composition of microorganisms in environmental samples has been studied using metagenomes, which are the collections of genomes of the microorganisms. Although many tools have been developed for taxonomy analysis based on different algorithms, variability of analysis outputs of existing tools from the same input metagenome datasets is the main obstacle for many researchers in this field. RESULTS: Here, we present a novel meta-analysis tool for metagenome taxonomy analysis, called TAMA, by intelligently integrating outputs from three different taxonomy analysis tools. Using an integrated reference database, TAMA performs taxonomy assignment for input metagenome reads based on a meta-score by integrating scores of taxonomy assignment from different taxonomy classification tools. TAMA outperformed existing tools when evaluated using various benchmark datasets. It was also successfully applied to obtain relative species abundance profiles and difference in composition of microorganisms in two types of cheese metagenome and human gut metagenome. CONCLUSION: TAMA can be easily installed and used for metagenome read classification and the prediction of relative species abundance from multiple numbers and types of metagenome read samples. TAMA can be used to more accurately uncover the composition of microorganisms in metagenome samples collected from various environments, especially when the use of a single taxonomy analysis tool is unreliable. TAMA is an open source tool, and can be downloaded at https://github.com/jkimlab/TAMA.


Assuntos
Bactérias/classificação , Classificação/métodos , Metagenoma , Metagenômica/métodos , Bactérias/genética , Bases de Dados Genéticas , Conjuntos de Dados como Assunto , Sequenciamento de Nucleotídeos em Larga Escala , Modelos Genéticos , Filogenia
12.
Nat Commun ; 11(1): 2250, 2020 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-32418985

RESUMO

Explanations for the Upper Pleistocene extinction of megafauna from Sahul (Australia and New Guinea) remain unresolved. Extinction hypotheses have advanced climate or human-driven scenarios, in spite of over three quarters of Sahul lacking reliable biogeographic or chronologic data. Here we present new megafauna from north-eastern Australia that suffered extinction sometime after 40,100 (±1700) years ago. Megafauna fossils preserved alongside leaves, seeds, pollen and insects, indicate a sclerophyllous forest with heathy understorey that was home to aquatic and terrestrial carnivorous reptiles and megaherbivores, including the world's largest kangaroo. Megafauna species diversity is greater compared to southern sites of similar age, which is contrary to expectations if extinctions followed proposed migration routes for people across Sahul. Our results do not support rapid or synchronous human-mediated continental-wide extinction, or the proposed timing of peak extinction events. Instead, megafauna extinctions coincide with regionally staggered spatio-temporal deterioration in hydroclimate coupled with sustained environmental change.


Assuntos
Mudança Climática/história , Extinção Biológica , Fósseis , Animais , Austrália , Carnivoridade , Classificação , Clima , Dromaiidae , Ecossistema , Florestas , História Antiga , Humanos , Macropodidae , Marsupiais , Nova Guiné , Paleontologia , Datação Radiométrica , Répteis , Urânio
13.
Nat Commun ; 11(1): 2115, 2020 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-32355257

RESUMO

Areas of endemism are important in biogeography because they capture facets of biodiversity not represented elsewhere. However, the scales at which they are relevant to research and conservation are poorly analysed. Here, we calculate weighted endemism (WE) and phylogenetic endemism (PE) separately for all birds and amphibians across the globe. We show that scale dependence is widespread for both indices and manifests across grain sizes, spatial extents and taxonomic treatments. Variations in taxonomic opinions-whether species are treated by systematic 'lumping' or 'splitting'-can profoundly affect the allocation of WE hotspots. Global patterns of PE can provide insights into complex evolutionary processes but this congruence is lost at the continental to country extents. These findings are explained by environmental heterogeneity at coarser grains, and to a far lesser extent at finer resolutions. Regardless of scale, we find widespread deficits of protection for endemism hotspots. Our study presents a framework for assessing areas for conservation that are robust to assumptions on taxonomy, spatial grain and extent.


Assuntos
Anfíbios/fisiologia , Biodiversidade , Aves/fisiologia , Filogenia , Animais , Evolução Biológica , Classificação , Conservação dos Recursos Naturais , Geografia , Modelos Lineares , Dinâmica Populacional , Especificidade da Espécie , Temperatura
14.
Medicine (Baltimore) ; 99(15): e19555, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32282704

RESUMO

To identify basic gait features and abnormal gait patterns that are common to different neurological or musculoskeletal conditions, such as cerebral stroke, Parkinsonian disorders, radiculopathy, and musculoskeletal pain.In this retrospective study, temporal-spatial, kinematic, and kinetic gait parameters were analyzed in 424 patients with hemiplegia after stroke, 205 patients with Parkinsonian disorders, 216 patients with radiculopathy, 167 patients with musculoskeletal pain, and 316 normal controls (total, 1328 subjects). We assessed differences according to the condition and used a community detection algorithm to identify subgroups within each condition. Additionally, we developed a prediction model for subgroup classification according to gait speed and maximal hip extension in the stance phase.The main findings can be summarized as follows. First, there was an asymmetric decrease of the knee/ankle flexion angles in hemiplegia and a marked reduction of the hip/knee range of motion with increased moment in Parkinsonian disorders. Second, three abnormal gait patterns, including fast gait speed with adequate maximal hip extension, fast gait speed with inadequate maximal hip extension, and slow gait speed, were found throughout the conditions examined. Third, our simple prediction model based on gait speed and maximal hip extension angle was characterized by a high degree of accuracy in predicting subgroups within a condition.Our findings suggest the existence of specific gait patterns within and across conditions. Our novel subgrouping algorithm can be employed in routine clinical settings to classify abnormal gait patterns in various neurological disorders and guide the therapeutic approach and monitoring.


Assuntos
Marcha , Dor Musculoesquelética/fisiopatologia , Transtornos Parkinsonianos/fisiopatologia , Radiculopatia/fisiopatologia , Acidente Vascular Cerebral/fisiopatologia , Idoso , Algoritmos , Fenômenos Biomecânicos , Classificação , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
15.
Science ; 368(6486)2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32241925

RESUMO

Understanding the extinction of Australopithecus and origins of Paranthropus and Homo in South Africa has been hampered by the perceived complex geological context of hominin fossils, poor chronological resolution, and a lack of well-preserved early Homo specimens. We describe, date, and contextualize the discovery of two hominin crania from Drimolen Main Quarry in South Africa. At ~2.04 million to 1.95 million years old, DNH 152 represents the earliest definitive occurrence of Paranthropus robustus, and DNH 134 represents the earliest occurrence of a cranium with clear affinities to Homo erectus These crania also show that Homo, Paranthropus, and Australopithecus were contemporaneous at ~2 million years ago. This high taxonomic diversity is also reflected in non-hominin species and provides evidence of endemic evolution and dispersal during a period of climatic variability.


Assuntos
Evolução Biológica , Extinção Biológica , Hominidae/anatomia & histologia , Hominidae/classificação , Animais , Cavernas , Classificação , Humanos , Crânio , África do Sul
16.
Zootaxa ; 4743(3): zootaxa.4743.3.12, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32230331

RESUMO

In a phylogenetic study of the insect order Strepsiptera, the peculiar paleotropical genus Lychnocolax Bohart, 1951 was recovered as the sister group to Stylopidae + Xenidae rather than as nested among the Myrmecolacidae (McMahon et al., 2011). Accordingly, the genus was removed from the myrmecolacids and placed in a family of its own (Kathirithamby Engel, 2014). Kathirithamby Engel (2014) erroneously attributed the family-group name to Bohart (1951) and therefore provided nothing more than diagnostic traits in the form of a dichotomous key to families. Cook (2019) rightly noted that Bohart (1951) provided only an account of the genus but retained it within Myrmecolacidae and did not establish a higher category for Lychnocolax. Accordingly, the first usage of a family-group name based on Lychnocolax was by Kathirithamby Engel (2014) (Cook, 2019). Unfortunately, their usage of the name does not meet the criteria required to make the name available from that date and source (ICZN, 1999). Specifically, after 1999 all new family-group names, aside from being based on an available type genus and accompanied by a description in words (ICZN, 1999: Arts. 13.1 and 13.2), must also meet the following criteria pertinent to the current case : 1) must be explicitly indicated as new (Art. 16.1), and 2) must be accompanied by a clear citation of the type genus (Art. 16.2). While Kathirithamby Engel (2014) did base the name on an available type genus and included diagnostic characters to differentiate the family from other groups, they did not explicitly indicate the name as new (since they erroneously attributed the name to Bohart), nor did they specifically note the type genus (even if it was apparent from the formation of the familial name). Thus, given the failure to satisfy Articles 16.1 and 16.2 (ICZN, 1999), the family-group name based on Lychnocholax Bohart, 1951 must be considered as unavailable from the publication of Kathirithamby Engel (2014). Although the family name has been mentioned a few times subsequently (e.g., Lu Liu, 2014; Kathirithamby et al., 2015; Engel et al., 2016; Kathirithamby, 2018; Cook, 2019), none of these latter uses satisfy the requirements of the ICZN (1999). Therefore, this nomenclatural oversight is here corrected utilizing the diagnostic traits outlined in the key of Kathirithamby Engel (2014).


Assuntos
Holometábolos , Animais , Classificação , Insetos , Fenótipo , Filogenia , Terminologia como Assunto
17.
Ecotoxicol Environ Saf ; 197: 110650, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32315788

RESUMO

Octylphenol (OP) is a widely distributed endocrine disrupting chemical (EDC), and can be commonly found in various and diverse environmental media. Previous studies have reported that OP exposure could cause many adverse effects on aquatic animals. However, knowledge concerning the impact of OP on lipid metabolism in amphibians was still limited. In our study, Rana chensinensis tadpoles were exposed to different OP concentrations (0, 10-8, 10-7 and 10-6 mol/L) from the Gosner stage (Gs) 25-38. The RNA-seq analysis of tadpole intestines was explored by RNA-seq, and six differentially expressed genes (DEGs) related to the fat digestion and absorption were validated by RT-qPCR. Moreover, we used 16s amplicon sequencing to evaluate effects of OP on intestinal microbiome in tadpoles, further determining the variations of lipid metabolism. Our results revealed that OP exposure influenced gene expression levels related to fat digestion and absorption and led to alteration of structure and composition of intestinal microbiome. At the phylum level, the Firmicutes/Bacteroidetes ratio was gradually decreased in OP exposure groups, which disrupted lipid metabolism. According to the results of intestinal microbial functional prediction, OP exposure interfered with metabolic function and increased risk of disease. These data provide us with powerful resources to assess the effects of OP on lipid metabolism by integrating RNAseq and 16s amplicon sequencing analysis of intestinal tract and intestinal microbiome.


Assuntos
Disruptores Endócrinos/toxicidade , Microbioma Gastrointestinal/efeitos dos fármacos , Intestinos/efeitos dos fármacos , Larva/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Fenóis/toxicidade , Animais , Classificação , Microbioma Gastrointestinal/genética , Expressão Gênica/efeitos dos fármacos , Sequenciamento de Nucleotídeos em Larga Escala , Intestinos/microbiologia , Larva/metabolismo , Metabolismo dos Lipídeos/genética , Anotação de Sequência Molecular , RNA/genética , Ranidae
18.
Parasit Vectors ; 13(1): 187, 2020 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-32272977

RESUMO

BACKGROUND: Monogenea van Beneden, 1858 is a group of parasitic flatworms, commonly found infecting bony fish. Several genera, such as Cichlidogyrus Paperna, 1960, are reported to include potential pathogenic species that can negatively impact aquaculture fish stocks. They can switch from introduced to native fish and vice versa. In Africa (and all over the world), fish species belonging to Cichlidae are often kept in aquaculture and represent a major source of food. Thus, research on the biodiversity and occurrence of monogenean species on these fish is of importance for aquaculture and conservation. The present study is a survey of the diversity of species of Cichlidogyrus in the south of the Democratic Republic of the Congo (DRC) on three cichlid species: Orthochromis sp. 'Lomami', Serranochromis cf. macrocephalus, and Tilapia sparrmanii Smith, 1840. METHODS: Specimens of Cichlidogyrus were isolated from the gills and mounted on glass slides with Hoyer's medium. The genital and haptoral hard parts were measured and drawn using interference contrast. RESULTS: In total, six species of Cichlidogyrus were found, all new to science: C. bulbophallus n. sp. and C. pseudozambezensis n. sp. on S. cf. macrocephalus, C. flagellum n. sp. and C. lobus n. sp. on T. sparrmanii, C. ranula n. sp. on S. cf. macrocephalus and Orthochromis sp. 'Lomami', and C. maeander n. sp. found on Orthochromis sp. 'Lomami' and T. sparrmanii. The first four species are considered to be strict specialists, C. ranula n. sp. an intermediate generalist and C. maeander n. sp. a generalist. These parasite species show morphological similarities to species found in the Lower Guinea and Zambezi ichthyofaunal provinces, which might be explained by past river capture events between river systems of the Congo Province and both these regions. CONCLUSIONS: Serranochromis cf. macrocephalus and Orthochromis sp. 'Lomami' can harbour respectively three and two species of Cichlidogyrus, all described in this study. Tilapia sparrmanii can harbour seven species, of which three are described in the present study. These results highlight the species diversity of this parasite genus in the Congo Basin.


Assuntos
Ciclídeos/parasitologia , Classificação , Trematódeos/classificação , Animais , Aquicultura , Biodiversidade , Coinfecção/parasitologia , Doenças dos Peixes/parasitologia , Produtos Pesqueiros/parasitologia , Peixes , Brânquias/parasitologia , Filogenia , Rios/parasitologia , Tilápia/parasitologia , Trematódeos/anatomia & histologia , Trematódeos/isolamento & purificação
19.
Proc Biol Sci ; 287(1926): 20200102, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32345167

RESUMO

Effectively conserving biodiversity with limited resources requires scientifically informed and efficient strategies. Guidance is particularly needed on how many living plants are necessary to conserve a threshold level of genetic diversity in ex situ collections. We investigated this question for 11 taxa across five genera. In this first study analysing and optimizing ex situ genetic diversity across multiple genera, we found that the percentage of extant genetic diversity currently conserved varies among taxa from 40% to 95%. Most taxa are well below genetic conservation targets. Resampling datasets showed that ideal collection sizes vary widely even within a genus: one taxon typically required at least 50% more individuals than another (though Quercus was an exception). Still, across taxa, the minimum collection size to achieve genetic conservation goals is within one order of magnitude. Current collections are also suboptimal: they could remain the same size yet capture twice the genetic diversity with an improved sampling design. We term this deficiency the 'genetic conservation gap'. Lastly, we show that minimum collection sizes are influenced by collection priorities regarding the genetic diversity target. In summary, current collections are insufficient (not reaching targets) and suboptimal (not efficiently designed), and we show how improvements can be made.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Animais , Classificação , Plantas , Tamanho da Amostra
20.
Nat Microbiol ; 5(5): 668-674, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32341570

RESUMO

Virus taxonomy emerged as a discipline in the middle of the twentieth century. Traditionally, classification by virus taxonomists has been focussed on the grouping of relatively closely related viruses. However, during the past few years, the International Committee on Taxonomy of Viruses (ICTV) has recognized that the taxonomy it develops can be usefully extended to include the basal evolutionary relationships among distantly related viruses. Consequently, the ICTV has changed its Code to allow a 15-rank classification hierarchy that closely aligns with the Linnaean taxonomic system and may accommodate the entire spectrum of genetic divergence in the virosphere. The current taxonomies of three human pathogens, Ebola virus, severe acute respiratory syndrome coronavirus and herpes simplex virus 1 are used to illustrate the impact of the expanded rank structure. This new rank hierarchy of virus taxonomy will stimulate further research on virus origins and evolution, and vice versa, and could promote crosstalk with the taxonomies of cellular organisms.


Assuntos
Classificação , Vírus/classificação , Vírus/genética , Doenças Transmissíveis/virologia , Ebolavirus/classificação , Ecologia , Evolução Molecular , Genes Virais , Herpesvirus Humano 1/classificação , Humanos , Vírus da SARS/classificação
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