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1.
J Fish Dis ; : e13995, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38953156

RESUMO

Intracellular parasites of the genus Glugea Thélohan, 1891 (Microsporidia) comprise about 34 putative species capable of causing high morbidity and mortality in freshwater and marine teleost fishes. In this study, we report on the first mass mortality event associated with Glugea sp. infecting free-ranging round sardinella Sardinella aurita in the southern Tyrrhenian Sea (Italy). Here, we describe the ultrastructure of mature spores of this microsporidian and characterize it molecularly, as well as report its phylogenetic position. Most of the affected fish showed an irregular swelling of its abdomen. At necropsy, a variable number of xenomas, spherical to ellipsoidal in shape, were found in the peritoneal cavity strongly attached to the viscera of all fish. Histological analysis revealed varying severity of chronic inflammation along with occasional necrosis in visceral organs associated with multiple xenoma proliferation. These pathological findings were considered the main cause of this mass mortality event. Morphologically, the present material was closely related to G. sardinellesis and G. thunni. The phylogenetically closest taxa to the newly SSU rDNA sequence were G. thunni and an erroneusly identified  G. plecoglossi, which were very closely related to each other, also suggesting that all these sequences might belong to the same species.

2.
Sensors (Basel) ; 24(12)2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38931656

RESUMO

Color reintegration is a restoration treatment that involves applying paint or colored plaster to an object of cultural heritage to facilitate its perception and understanding. This study examines the impact of lighting on the visual appearance of one such restored piece: a tiled skirting panel from the Nasrid period (1238-1492), permanently on display at the Museum of the Alhambra (Spain). Spectral images in the range of 380-1080 nm were obtained using a hyperspectral image scanner. CIELAB and CIEDE2000 color coordinates at each pixel were computed assuming the CIE 1931 standard colorimetric observer and considering ten relevant illuminants proposed by the International Commission on Illumination (CIE): D65 plus nine white LEDs. Four main hues (blue, green, yellow, and black) can be distinguished in the original and reintegrated areas. For each hue, mean color difference from the mean (MCDM), CIEDE2000 average distances, volumes, and overlapping volumes were computed in the CIELAB space by comparing the original and the reintegrated zones. The study reveals noticeable average color differences between the original and reintegrated areas within tiles: 6.0 and 4.7 CIEDE2000 units for the yellow and blue tiles (with MCDM values of 3.7 and 4.5 and 5.8 and 7.2, respectively), and 16.6 and 17.8 CIEDE2000 units for the black and green tiles (with MCDM values of 13.2 and 12.2 and 10.9 and 11.3, respectively). The overlapping volume of CIELAB clouds of points corresponding to the original and reintegrated areas ranges from 35% to 50%, indicating that these areas would be perceived as different by observers with normal color vision for all four tiles. However, average color differences between the original and reintegrated areas changed with the tested illuminants by less than 2.6 CIEDE2000 units. Our current methodology provides useful quantitative results for evaluation of the color appearance of a reintegrated area under different light sources, helping curators and museum professionals to choose optimal lighting.

3.
Int J Mol Sci ; 25(2)2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38256216

RESUMO

Regenerative Peripheral Nerve Interfaces (RPNIs) encompass neurotized muscle grafts employed for the purpose of amplifying peripheral nerve electrical signaling. The aim of this investigation was to undertake an analysis of the extant literature concerning animal models utilized in the context of RPNIs. A systematic review of the literature of RPNI techniques in animal models was performed in line with the PRISMA statement using the MEDLINE/PubMed and Embase databases from January 1970 to September 2023. Within the compilation of one hundred and four articles employing the RPNI technique, a subset of thirty-five were conducted using animal models across six distinct institutions. The majority (91%) of these studies were performed on murine models, while the remaining (9%) were conducted employing macaque models. The most frequently employed anatomical components in the construction of the RPNIs were the common peroneal nerve and the extensor digitorum longus (EDL) muscle. Through various histological techniques, robust neoangiogenesis and axonal regeneration were evidenced. Functionally, the RPNIs demonstrated the capability to discern, record, and amplify action potentials, a competence that exhibited commendable long-term stability. Different RPNI animal models have been replicated across different studies. Histological, neurophysiological, and functional analyses are summarized to be used in future studies.


Assuntos
Neovascularização Patológica , Animais , Camundongos , Potenciais de Ação , Bases de Dados Factuais , Macaca , Modelos Animais
4.
Parasitol Res ; 122(1): 157-165, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36418649

RESUMO

The gill monogenean Sparicotyle chrysophrii (Van Beneden & Hesse, 1863) Mamaev, 1984 is a specific and common parasite of wild and cultured gilthead sea bream Sparus aurata Linnaeus, 1758, able to cause disease and mortality in aquaculture systems. Few molecular studies have been carried out on this monogenean, and its population structure and genetic diversity are barely known. This study provides the first contribution to the population genetic variation of S. chrysophrii, based on two molecular markers - the structural ribosomal RNA (rRNA) for the large subunit (28S) and the cytochrome c oxidase subunit I (COI) gene. Samples were collected from the gills of farmed and wild S. aurata from Italy and the Spanish Mediterranean. The analysis included previously published sequences. The 28S rDNA analysis was consistent with previous studies of specimens isolated from S. aurata and confirmed the presence of only one species on the gills of this host in the Mediterranean Sea. The COI sequences analysis suggested that the samples isolated in a previous study from a different host species, wild Boops boops (Linnaeus, 1758) in the Adriatic Sea, may represent a new undescribed sister species of S. chrysophrii. The low nucleotide diversity of S. chrysophrii isolated only from S. aurata versus the high haplotype diversity revealed small differences between haplotypes. The haplotypes shared between wild and farmed hosts from Spain provided the first molecular evidence of the possible transfer of S. chrysophrii between wild and farmed populations of S. aurata. The mtDNA COI analysis did not show a clear genetic structure, probably the result of several factors including coevolution, wild and farmed host interactions, and host population structure in space and time.


Assuntos
Perciformes , Dourada , Trematódeos , Animais , Dourada/parasitologia , Mar Mediterrâneo , Trematódeos/genética , Variação Genética
5.
Parasitology ; 149(13): 1695-1701, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35735055

RESUMO

The microcotylid Sciaenacotyle pancerii is a pathogenic monogenean infecting Argyrosomus regius, a candidate for species diversification in the Mediterranean aquaculture. Life-history stages of S. pancerii commonly co-occur in field infections, but to date, morphological data have only been provided for oncomiracidia and adults although identifying life-history stages can be useful in infection management. A total of 114 specimens of S. pancerii were analysed to characterize the developmental events and to assess morphological and morphometric variations before and after maturity. The post-larval development of S. pancerii is characterized by: expansion and bifurcation of the gut, loss of the larval haptor, protandrous development of the genitalia and vitellaria formation. The size variability of larval hooks, hamuli and germanium of S. pancerii is firstly reported and dimensional ranges of parasite body, haptor, testes, posteriormost clamps and eggs are widened. The size of most of the diagnostic features of S. pancerii significantly increases after parasite maturity and therefore, only those specimens with more than 116 clamps should be considered for minimising development-related variability in size. The high number of clamps, their fast development and the asymmetry in their size and arrangement suggest that S. pancerii may use a mixed attachment strategy between the closely related microcotylids and heteraxinids. This combination of features may be host related and linked to the gill structure of the sciaenid fish and the phylogenetic position of the genus Sciaenacotyle; distant from other microcotylids while close to heteraxinid species.


Assuntos
Doenças dos Peixes , Perciformes , Trematódeos , Animais , Filogenia , Doenças dos Peixes/parasitologia , Brânquias/parasitologia , Perciformes/parasitologia , Larva
6.
Parasitol Res ; 120(6): 1949-1963, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33884492

RESUMO

The genus Cardicola Short, 1953 has the highest number of species within the family Aporocotylidae (Trematoda: Digenea). Five Cardicola species have been reported to date in the Mediterranean Sea, one of them in the gilthead seabream Sparus aurata L. Analyses of infected S. aurata recovered from cultured fish off Sardinia (Italy) and from wild and cultured fish off the Levantine coast (Southeastern Spain) have revealed the presence of two species identified as Cardicola aurata Holzer, Montero, Repullés, Nolan, Sitjà-Bobadilla, Álvarez-Pellitero, Zarza and Raga, 2008 and Cardicola mediterraneus n. sp.. New morphological and molecular data are provided for both species. Features of C. aurata specimens differ slightly from those of the original description of the species, the most important differences being the longer extension of the metraterm and the central and posterior position of the female genital pore. Cardicola mediterraneus n. sp. can be easily distinguished from other Cardicola species by two unique specific characters: (i) the very unequal posterior caeca length and (ii) the shape of the testis, deeply notched at the anterior extremity. Cardicola spp. from sparids occupy a basal phylogenetic position respect the other congeneric species. The genus Cardicola has a complex taxonomy and shows high intrageneric differences for both 28S and ITS2 rDNAs, similar to the intergeneric differences among other aporocotylid genera, suggesting that it could be split. The presence of two Cardicola species could hamper treatment design and application; thus, data discriminating species herein reported can improve the infection management in fish farms.


Assuntos
Doenças dos Peixes/parasitologia , Dourada/parasitologia , Trematódeos/classificação , Infecções por Trematódeos/veterinária , Animais , DNA Ribossômico , DNA Espaçador Ribossômico/genética , Feminino , Doenças dos Peixes/epidemiologia , Mar Mediterrâneo/epidemiologia , Filogenia , Especificidade da Espécie , Trematódeos/isolamento & purificação , Infecções por Trematódeos/epidemiologia , Infecções por Trematódeos/parasitologia
7.
Neuromodulation ; 23(5): 698-703, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30786089

RESUMO

OBJECTIVE: One of the physiopathological hypothesis behind complex regional pain syndrome (CRPS) type I involves the deep-tissue hypoxia of the affected areas. Spinal cord stimulation (SCS) appears to be effective in the treatment of these patients. We evaluated whether ESCS modifies tissue oxygen saturation (StO2 ) measured with near-infrared spectroscopy (NIRS) in the affected limbs in patients diagnosed with CRPS type I. MATERIALS AND METHODS: Nonrandomized, cross-sectional study that evaluated 16 patients with CRPS type I who were receiving SCS applied to the posterior cords. NIRS was used to evaluate baseline StO2 (primary outcome) and variations in StO2 (secondary outcome) during an ischemia-reperfusion test performed using a vascular occlusion test, comparing the hands of limbs unilaterally affected by CRPS type I with the unaffected contralateral hands. We also determined whether the variations in StO2 were related to a modification in the percentage of subjective pain improvement and in the visual analog scale score. RESULTS: The baseline StO2 of the affected hands was significantly higher than that of the unaffected hands (mean 4.7%; 95% confidence interval: 1.41, 6.7; p = 0.005). Variations in StO2 during the ischemia-reperfusion test revealed no differences between affected and unaffected hands. No significant correlations were detected between baseline StO2 values or variations in StO2 during the vascular occlusion test and the pain measurements. CONCLUSIONS: Baseline StO2 evaluated by NIRS was greater in the affected hands of patients with CRPS type I treated with SCS than in the unaffected, contralateral hands.


Assuntos
Mãos/patologia , Oximetria , Distrofia Simpática Reflexa , Estimulação da Medula Espinal , Estudos Transversais , Humanos , Oxigênio , Distrofia Simpática Reflexa/diagnóstico por imagem , Distrofia Simpática Reflexa/terapia , Espectroscopia de Luz Próxima ao Infravermelho
8.
Int J Mol Sci ; 21(16)2020 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-32781742

RESUMO

Neurodegenerative diseases are a major burden for our society, affecting millions of people worldwide. A main goal of past and current research is to enhance our understanding of the mechanisms underlying proteotoxicity, a common theme among these incurable and debilitating conditions. Cell proteome alteration is considered to be one of the main driving forces that triggers neurodegeneration, and unraveling the biological complexity behind the affected molecular pathways constitutes a daunting challenge. This review summarizes the current state on key processes that lead to cellular proteotoxicity in Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, providing a comprehensive landscape of recent literature. A foundational understanding of how proteotoxicity affects disease etiology and progression may provide essential insight towards potential targets amenable of therapeutic intervention.


Assuntos
Doenças Neurodegenerativas/patologia , Proteínas/toxicidade , Animais , Humanos , Doenças Neurodegenerativas/tratamento farmacológico , Agregados Proteicos
9.
AIDS Care ; 31(2): 265-269, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-29985054

RESUMO

This study performed a content analysis of the language of the Spanish judgements addressing the sexual transmission of HIV in order to determine its possible interrelationship with HIV-related stigma. All judgements and writs dictated by Spanish penal and civil jurisdictions between 1981 and December 2016 were obtained through a systematic search of the Spanish legal databases. The inclusion criterion was that the possible transmission of HIV was judged as an individual infraction, regardless of whether other infractions were involved. Twenty judgements were selected and analysed through direct content analysis assisted by the software MAXQDA 12. The majority of the cases (85%) were brought before the penal jurisdiction. Most of the judgements applied the crimes of bodily harm or grievous bodily harm (75%). Aspects closely related to the determinants of HIV-related stigma, such as the perception of HIV as a severe and easily transmitted infection, and attributions of responsibility and blame to people with HIV, were found in the judgements' reasoning. They were associated with outdated scientific and technical knowledge. Furthermore, some arguments found are repeated literally and successively in several judgments from different years, ignoring medical advances. Most plaintiffs were unaware of their sexual partner's HIV status. The scarce results found regarding the concealment of HIV status suggested that fear of stigma could be the reason thereof. The results suggested that training legal professionals in the epidemiological, clinical, and social aspects of HIV could influence stigma reduction, leading to a more objective consideration of the characteristics of this infection.


Assuntos
Crime , Infecções por HIV/transmissão , Idioma , Estigma Social , Adulto , Medo , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Linguística , Masculino , Parceiros Sexuais , Comportamento Social , Revelação da Verdade
10.
Parasitol Res ; 118(2): 433-440, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30607605

RESUMO

Acanthocephalans display a two-host life cycle that involves arthropods as intermediate hosts and vertebrates as definitive hosts. Some species also use paratenic hosts to bridge the trophic gap between both obligatory hosts. However, the relative role of these paratenic hosts in the transmission to definitive hosts has seldom been assessed quantitatively. We report on infection patterns of cystacanths of Corynosoma australe Johnston, 1937 in 20 common teleost species and the Argentine shortfin squid Illex argentinus (Castellanos) from the Patagonian shelf of Argentina. We also explore the role of different fish species in the transmission of C. australe to the most important definitive host in the area, i.e. the South American sea lion Otaria flavescens Shaw. Cystacanths of C. australe were found in all host species except Heliconus lahillei Norman, Merluccius hubbsi Marini and I. argentinus. In eight fish species, the prevalence of C. australe was > 50% and mean intensity > 4, i.e. Acanthistius patachonicus (Jenyns), Nemadactylus bergi (Norman), Paralichthys isosceles Jordan, Percophis brasiliensis Quoy & Gaimard, Prionotus nudigula Ginsburg, Scomber colias Gmelin, Raneya brasiliensis (Kaup) and Xystreurys rasile (Jordan). Two surveys on the trophic ecology of South American sea lions in the study area consistently found a generalist diet dominated by M. hubbsi, and data on the frequency of occurrence and number of other fish and cephalopod species in stomach contents strongly suggest that only R. brasiliensis may play a prominent role in the transmission of C. australe. This result raises interesting questions on the costs of paratenicity.


Assuntos
Acantocéfalos/fisiologia , Doenças dos Peixes/transmissão , Helmintíase Animal/transmissão , Leões-Marinhos/parasitologia , Animais , Argentina , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/parasitologia , Peixes/parasitologia , Cadeia Alimentar , Helmintíase Animal/epidemiologia , Helmintíase Animal/parasitologia , Especificidade de Hospedeiro , Jordânia
11.
Sensors (Basel) ; 19(24)2019 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-31817910

RESUMO

This work presents a spectral color-imaging procedure for the detailed colorimetric study of real artworks under arbitrary illuminants. The results demonstrate this approach to be a powerful tool for art and heritage professionals when deciding which illumination to use in museums, or which conservation or restoration techniques best maintain the color appearance of the original piece under any illuminant. Spectral imaging technology overcomes the limitations of common area-based point-measurement devices such as spectrophotometers, allowing a local study either pixelwise or by selected areas. To our knowledge, this is the first study available that uses the proposed CIE (Commission Internationale de l'Éclairage) light-emitting diode (LED) illuminants in the context of art and heritage science, comparing them with the three main CIE illuminants A, D50, and D65. For this, the corresponding colors under D65 have been calculated using a chromatic adaptation transform analogous to the one in CIECAM02. For the sample studied, the CIE LED illuminants with the lowest average CIEDE2000 color differences from the standard CIE illuminants are LED-V1 for A and LED-V2 for D50 and D65, with 1.23, 1.07, and 1.57 units, respectively. The work studied is a Moorish epigraphic frieze of plasterwork with a tiled skirting from the Nasrid period (12th-15th centuries) exhibited in the Museum of the Alhambra (Granada, Spain).

12.
Eye Contact Lens ; 44 Suppl 2: S285-S291, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29373387

RESUMO

PURPOSE: To analyze the state of scientific publications in the field of scleral lenses applying a bibliometric study. METHODS: The database used in this bibliometric study was SCOPUS, the largest abstract and citation database of peer-reviewed literature: scientific journals, books, and conference proceedings. Using remote download techniques, articles published between 1962 (year of first registrations) and 2015 were selected by entering the main descriptors: "scleral contact lenses" and "scleral lenses," limiting the field for the article, keywords, and abstract, linked with the OR tab. We applied the following bibliometric indicators: Price index, doubling time and annual growth rate, Price transience index, Lotka law of scientific productivity, and Bradford zones. RESULTS: The authors recovered 361 contributions (articles, reviews, letters to the editor, etc.) for 1962 to 2016. The distribution for five-year periods shows a significant increase in 2012 to 2016, with a growth of 222.22% in comparison with the previous period 2012 to 2016. The countries with the highest production are the United states with 135 contributions, United Kingdom with 46, and India with 19. The most productive institutions are Harvard Medical school, Boston Foundation for Sight, and Moorfields Eye Hospital National Health Service Foundation Trust. Classification of authors based on productivity is strongly concentrated in small producers, with a transient index of 59.03. The total number of authors is 891, representing a coauthor index of 2.47 for the 361 documents retrieved. The authors with the highest productivity are Kenneth W. Pullum, Perry Rosenthal, and Deborah S. Jacobs, with an h-index between 12 and 19 documents. The number of documents published on scleral lenses shows a significant increase in the last 5 years, and currently, they represent only 1.44% of all publications on contact lenses. CONCLUSIONS: Bibliometric studies have become essential tools for evaluating scientific activity, allowing an overview of the growth, size, and distribution of scientific literature associated with a particular discipline.


Assuntos
Bibliometria , Pesquisa Biomédica/estatística & dados numéricos , Lentes de Contato , Editoração/estatística & dados numéricos , Esclera , Humanos , Editoração/tendências
13.
Sensors (Basel) ; 18(5)2018 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-29751584

RESUMO

Many researchers have explored the relationship between recurrent neural networks and finite state machines. Finite state machines constitute the best-characterized computational model, whereas artificial neural networks have become a very successful tool for modeling and problem solving. The neurally-inspired lateral inhibition method, and its application to motion detection tasks, have been successfully implemented in recent years. In this paper, control knowledge of the algorithmic lateral inhibition (ALI) method is described and applied by means of finite state machines, in which the state space is constituted from the set of distinguishable cases of accumulated charge in a local memory. The article describes an ALI implementation for a motion detection task. For the implementation, we have chosen to use one of the members of the 16-nm Kintex UltraScale+ family of Xilinx FPGAs. FPGAs provide the necessary accuracy, resolution, and precision to run neural algorithms alongside current sensor technologies. The results offered in this paper demonstrate that this implementation provides accurate object tracking performance on several datasets, obtaining a high F-score value (0.86) for the most complex sequence used. Moreover, it outperforms implementations of a complete ALI algorithm and a simplified version of the ALI algorithm—named “accumulative computation”—which was run about ten years ago, now reaching real-time processing times that were simply not achievable at that time for ALI.

14.
J Fish Biol ; 93(4): 586-596, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29956313

RESUMO

Marine protected areas are considered a useful tool to preserve and recover the biodiversity of ecosystems. It is suggested that fisheries not only affect populations of target and bycatch species but also their parasite communities. Parasites can indicate fishery effects on host species and also on the whole local community, but the effects of fisheries and protection measures on parasite communities are relatively unknown. This study analyses parasite communities of the white seabream Diplodus sargus sargus in order to assess potential effects exerted by protection measures within and by fisheries outside a reserve in the western Mediterranean Sea. This small scale analysis offered the opportunity to study different degrees of fishery effects on parasite infracommunities, without considering climatic effects as an additional factor. Parasite infracommunities of fishes from the no-take zone (NTZ) differed in their composition and structure compared with areas completely or partially open to fisheries. The detected spatial differences in the infracommunities derived from generalist parasites and varied slightly between transmission strategies. Monoxenous parasites were richer and more diverse in both fished areas, but more abundant in the no-take, whereas richness and abundance of heteroxenous parasites were higher for the NTZ. In addition to host body size as one factor explaining these spatial variations, differences within parasite infracommunities between the areas may also be linked to increased host densities and habitat quality since the implementation of the NTZ and its protection measures.


Assuntos
Biodiversidade , Interações Hospedeiro-Parasita , Parasitos/classificação , Dourada/parasitologia , Animais , Tamanho Corporal , Ecossistema , Pesqueiros , Ilhas , Mar Mediterrâneo , Parasitos/fisiologia
15.
Malays J Med Sci ; 25(3): 40-55, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-30899186

RESUMO

OBJECTIVE: We carried out a bibliometric study on the scientific papers related to second-generation antipsychotic drugs (SGAs) in Malaysia. METHODS: With the SCOPUS database, we selected those documents made in Malaysia whose title included descriptors related to SGAs. We applied bibliometric indicators of production and dispersion, as Price's law and Bradford's law, respectively. We also calculated the participation index of the different countries. The bibliometric data were also been correlated with some social and health data from Malaysia (total per capita expenditure on health and gross domestic expenditure on R&D). RESULTS: We found 105 original documents published between 2004 and 2016. Our results fulfilled Price's law, with scientific production on SGAs showing exponential growth (r = 0.401, vs. r = 0.260 after linear adjustment). The drugs most studied are olanzapine (9 documents), clozapine (7), and risperidone (7). Division into Bradford zones yields a nucleus occupied by the Medical Journal of Malaysia, Singapore Medical Journal, Australian and New Zealand Journal of Psychiatry, and Pharmacogenomics. Totally, 63 different journals were used, but only one in the top four journals had an impact factor being greater than 3. CONCLUSION: The publications on SGAs in Malaysia have undergone exponential growth, without evidence a saturation point.

16.
Curr Top Microbiol Immunol ; 392: 161-79, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26210988

RESUMO

RNA viruses get extinct in a process called lethal mutagenesis when subjected to an increase in their mutation rate, for instance, by the action of mutagenic drugs. Several approaches have been proposed to understand this phenomenon. The extinction of RNA viruses by increased mutational pressure was inspired by the concept of the error threshold. The now classic quasispecies model predicts the existence of a limit to the mutation rate beyond which the genetic information of the wild type could not be efficiently transmitted to the next generation. This limit was called the error threshold, and for mutation rates larger than this threshold, the quasispecies was said to enter into error catastrophe. This transition has been assumed to foster the extinction of the whole population. Alternative explanations of lethal mutagenesis have been proposed recently. In the first place, a distinction is made between the error threshold and the extinction threshold, the mutation rate beyond which a population gets extinct. Extinction is explained from the effect the mutation rate has, throughout the mutational load, on the reproductive ability of the whole population. Secondly, lethal defection takes also into account the effect of interactions within mutant spectra, which have been shown to be determinant for the understanding the extinction of RNA virus due to an augmented mutational pressure. Nonetheless, some relevant issues concerning lethal mutagenesis are not completely understood yet, as so survival of the flattest, i.e. the development of resistance to lethal mutagenesis by evolving towards mutationally more robust regions of sequence space, or sublethal mutagenesis, i.e., the increase of the mutation rate below the extinction threshold which may boost the adaptability of RNA virus, increasing their ability to develop resistance to drugs (including mutagens). A better design of antiviral therapies will still require an improvement of our knowledge about lethal mutagenesis.


Assuntos
Modelos Genéticos , Mutagênese , Vírus de RNA/genética , Evolução Molecular , Mutação , Taxa de Mutação
17.
Syst Parasitol ; 94(5): 609-619, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28447298

RESUMO

A new microcotylid, Tinrovia mamaevi n. sp. (Monogenea: Polyopisthocotylea), is described from the gills of Notacanthus bonaparte Risso (Notacanthiformes: Notacanthidae), sampled in the Western Mediterranean and North East Atlantic. This species is allocated to the subfamily Syncoelicotylinae Mamaev & Zubchenko, 1978 due to the possession of a symmetrical haptor with two separate frills. The clamps in T. mamaevi n. sp. are of the "microcotylid" type, arranged in two distinct lateral haptoral frills; the genital atrium and the copulatory organ are armed and the vaginal pore is unarmed. The new species differs from the type- and only species of the genus, T. papiliocauda Mamaev, 1987, in having a shorter and narrower haptor with a smaller number of clamps. Clamps are also smaller in the new species, testes are more numerous, the genital atrium is smaller, divided into two lateral lobes (instead of five) with a smaller number of spines and the eggs have a short and a long filament (instead of two short filaments). The host species and locality of T. mamaevi n. sp. also differ as T. papiliocauda which was recorded in Notacanthus sexspinis Richardson from the South Pacific.


Assuntos
Peixes/parasitologia , Trematódeos/classificação , Animais , Oceano Atlântico , Brânquias/parasitologia , Especificidade de Hospedeiro , Mar Mediterrâneo , Especificidade da Espécie , Trematódeos/anatomia & histologia
18.
Syst Parasitol ; 94(6): 669-688, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28573546

RESUMO

A new aporocotylid, Skoulekia erythrini n. sp., is described from the heart, cephalic kidney and gill blood vessels of the common pandora Pagellus erythrinus (L.) collected from several localities of the western Mediterranean off Spain. The new species differs from the type- and only species of the genus, S. meningialis Alama-Bermejo, Montero, Raga & Holzer, 2011 in possessing a symmetrical body (vs laterally curved), short tegumental spines (3-4 vs 7-10 µm) without hooked ends, diffuse (vs conspicuous) oesophageal gland-cells, a relatively longer oesophagus, a testis that is shorter in relation to body length and a much smaller seminal vesicle (17-34 × 10-26 vs 33-101 × 27-97 µm). Elongated ellipsoidal eggs of S. erythrini n. sp. were found trapped in gill vessels in histological sections. Phylogenetic analyses based on partial 28S rDNA and ITS2 sequences supported the placement of the new species within Skoulekia and the close relationships of this genus with Psettarium Goto & Ozaki, 1929 and Pearsonellum Overstreet & Køie, 1986. Skoulekia meningialis is described from a new sparid host, Diplodus puntazzo (Walbaum), collected off Santa Pola, Spain. The new morphological data for the two Skoulekia spp. and a re-examination of three paratypes of S. meningialis pinpointed features amending both the description of S. meningialis and the generic diagnosis of Skoulekia.


Assuntos
Perciformes/classificação , Trematódeos/classificação , Animais , DNA Espaçador Ribossômico/genética , Mar Mediterrâneo , Perciformes/anatomia & histologia , RNA Ribossômico 28S/genética , Especificidade da Espécie , Trematódeos/anatomia & histologia , Trematódeos/genética
19.
J Theor Biol ; 407: 303-317, 2016 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-27473768

RESUMO

Reductive genome evolution is a universal phenomenon observed in endosymbiotic bacteria in insects. As the genome reduces its size and irreversibly losses coding genes, the functionalities of the cell system, including the energetics processes, are more restricted. Several energetic pathways can also be lost. How do these reduced metabolic networks sustain the energy needs of the system? Among the bacteria with reduced genomes Candidatus Portiera aleyrodidarum, obligate endosymbiont of whiteflies, represents an extreme case since lacks several key mechanisms for ATP generation. Thus, to analyze the cell energetics in this system, a genome-scale metabolic model of this endosymbiont was constructed, and its energy production capabilities dissected using stoichiometric analysis. Our results suggest that energy generation is coupled to the synthesis of essential amino acids and carotenoids, crucial metabolites in the symbiotic association. A deeper insight showed that ATP production via carotenoid synthesis is also connected with amino acid production. This unusual association of energy production with anabolism suggests that, although minimized, endosymbiont metabolic networks maintain a remarkable biosynthetic potential.


Assuntos
Aminoácidos/metabolismo , Metabolismo Energético , Halomonadaceae/metabolismo , Hemípteros/microbiologia , Simbiose , Animais , Genoma Bacteriano , Halomonadaceae/genética , Análise do Fluxo Metabólico , Redes e Vias Metabólicas , Modelos Biológicos , beta Caroteno/metabolismo
20.
Parasitology ; 143(10): 1330-9, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27173779

RESUMO

Between 2008 and 2011, the head of 150 Euthynnus alletteratus (Osteichthyes: Scombridae) caught inshore off the southeastern Iberian coast (western Mediterranean Sea) were examined for parasites. Two monogeneans, four didymozoid trematodes and four copepods were found. Parasite abundance showed a positive relationship with the annual sea surface temperature, except for Pseudocycnus appendiculatus, but negative with the sea depth (Capsala manteri, Neonematobothrium cf. kawakawa and Caligus bonito). Prevalences and mean abundances differed significantly among sampling areas, except for C. manteri, Oesophagocystis sp. 2 and Ceratocolax euthynni, and sampling years (Melanocystis cf. kawakawa, N.cf. kawakawa, P. appendiculatus and Unicolax collateralis). Results indicate that the parasite abundances of E. alletteratus in the western Mediterranean Sea depend mainly on regional environmental variables, which can show interannual variations. The presence of pelagic parasites, i.e. didymozoids and P. appendiculatus, could indicate that E. alletteratus migrates between inshore and offshore pelagic domains. The different parasite faunas reported in E. alletteratus populations from the western Atlantic Ocean and the Mediterranean Sea appear to point out the geographical host isolation. These results suggest that E. alletteratus inhabiting the western Mediterranean Sea performs inshore-offshore small-scale migrations, and not transoceanic migrations between the western Atlantic Ocean and Mediterranean Sea.


Assuntos
Interações Hospedeiro-Parasita , Parasitos/isolamento & purificação , Perciformes/fisiologia , Perciformes/parasitologia , Migração Animal , Animais , Oceano Atlântico , Copépodes/genética , Doenças dos Peixes/parasitologia , Mar Mediterrâneo , Parasitos/classificação , Parasitos/genética , Prevalência , Trematódeos/genética , Trematódeos/isolamento & purificação
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