RESUMO
In this contribution, we offer the fifth installment of a series focusing on the phylogeny and taxonomy of powdery mildews. This paper is the second segment evaluating the genus Erysiphe. The first treatment of Erysiphe focused on phylogenetically basal species in the "Uncinula lineage." This research presents a phylogenetic-taxonomic assessment of species that form the group previously referred to as the "Microsphaera lineage." Given the size of the group, we split the treatment of this lineage of Erysiphe species into two parts based on their phylogenetic placement. Phylogenetic trees based on ITS+28S data are supplemented by sequences of additional markers (CAM, GADPH, GS, RPB2, and TUB). Included in the analysis of the Microsphaera lineage is the "Erysiphe aquilegiae complex" (group, clade, cluster), which encompasses sequences obtained from an assemblage of Erysiphe species with insufficient resolution in rDNA analyses. Attempts have been made to resolve this group at the species level by applying a multilocus approach. A detailed discussion of the "Erysiphe aquilegiae complex" is provided. Sequences are provided for the first time for several species, particularly North American species, such as Erysiphe aggregata, E. erineophila, E. parnassiae, and E. semitosta. Ex-type sequences for Microsphaera benzoin and M. magnusii have been retrieved. Alphitomorpha penicillata, Microsphaera vanbruntiana, and M. symphoricarpi are epitypified with ex-epitype sequences. The new species Erysiphe alnicola, E. deutziana, E. cornigena, E. lentaginis, and E. sambucina are described, the new combinations E. lauracearum, E. passiflorae, and E. sambucicola are introduced, and the new name E. santali is proposed.
Assuntos
Ascomicetos , Erysiphe , Filogenia , Erysiphe/genética , Doenças das Plantas , DNA Fúngico/genéticaRESUMO
The apothecial fungus Ramomarthamyces octomerus sp. nov. is described from specimens collected in Mediterranean climate regions in southern Portugal, Spain (Canary Islands), and the Dalmatian region of Croatia. Presumably saprobic, R. octomerus occurs on intact, decorticated wood of Laurus novocanariensis and Olea europaea. Ascospores are cylindric-ellipsoid and seven-septate. Surprisingly, in our four-locus phylogenetic analysis (nuSSU, ITS1-5.8S-ITS2, LSU, mtSSU), this fungus clusters among species of Cyclaneusma, Marthamyces, Naemacyclus, and Ramomarthamyces in a core Marthamycetaceae clade that circumscribes primarily leaf-inhabiting, filiform-spored species. In addition, the asci of R. octomerus possess an amyloid pore, but the reaction varies between specimens collected in the Canary Islands and those collected in Portugal and Croatia. The occurrence of an amyloid reaction in the asci of R. octomerus challenges the characterization of Marthamycetales taxa as possessing inamyloid asci. In our discussion we provide background and analysis of these notable observations.
RESUMO
Tympanis species (Leotiales) are plant pathogens distributed mostly in northern temperate ecosystems. The diversity and identity of some species remains unclear. Tympanis vagabunda, found in Sicilia (Italy) on dry twigs of Rosa, Rubus, and Pistacia, is one example of an obscure and poorly known species. During the study of its type specimen in S, which contained one twig with a wood anatomy fitting neither of the three mentioned hosts, the microanatomic structures indicated that it belongs to the genus Rutstroemia (Helotiales). To investigate its identity, the types of R. fruticeti, R. juniperi, R. urceolus, and R. longiasca were studied for comparison. The species for which molecular data were available were included in a dataset that contained identified species of Rutstroemia, along with other select species from the families Rutstroemiaceae and Sclerotiniaceae. R. fruticeti, a saprobe frequently reported from Rubus fruticosus in Europe, is found to be a later synonym of T. vagabunda, and the combination Rutstroemia vagabunda is proposed. R. juniperi is an infrequently reported European species on twigs of Juniperus and is morphologically hard to distinguish from R. vagabunda; available molecular data support its recognition as a distinct species. R. longiasca differs from R. vagabunda in its black apothecia, smaller asci, and narrower ascospores. R. urceolus differs from R. vagabunda in having black apothecia and smaller inamyloid asci, and excipulum at the flanks and margin is composed of dark-walled hyphae.
RESUMO
This contribution is part of a series devoted to the phylogeny and taxonomy of powdery mildews, with an emphasis on North American taxa. An overview of Cystotheca species is given, including references to ex-type sequences or, if unavailable, proposals for representative reference sequences for phylogenetic-taxonomic purposes. The new species C. mexicana is described, based on Mexican collections on Quercus glaucoides × Quercus microphylla and Quercus liebmannii × Q. microphylla. Cystotheca lanestris is reported for the first time worldwide on Quercus laceyi (Collected in Mexico) and on Q. toumeyi (collected in Arizona, USA). Cystotheca lanestris on Q. agrifolia and on Q. cerris is reported for the first time in Mexico. Epitypes with ex-epitype sequences are designated for Cystotheca wrightii, Lanomyces tjibodensis (= C. tjibodensis), Sphaerotheca kusanoi, and S. lanestris (C. lanestris).
Assuntos
Quercus , Filogenia , México , ArizonaRESUMO
The monotypic "bulbilliferous hyphomycete" genus Taxomyces was erected in 1993 for a fungal endophyte isolated from the Yew tree Taxus brevifolia and named Taxomyces andreanae. This fungus was reported to produce the plant-derived anti-cancer drug taxol. The original description of the fungus was not conclusive as to its taxonomic position because no sporulation or other salient morphological features were reported. Consequently, the taxonomic affinities of this fungus have remained obscure. However, a full genome sequence of this strain was generated by a German research group in 2013, in an unsuccessful attempt to detect the biosynthesis genes encoding for taxol. This prompted us to search for phylogenetic marker genes and compare those with the data that recently have become available from state-of-the-art polyphasic taxonomic studies. Surprisingly, the strain turned out to belong to the phlebioid clade of wood-destroying Basidiomycota as inferred from a comparison of its partial ITS, the 28S rDNA (LSU), the RNA polymerase II largest subunit (rpb1), the RNA polymerase II second largest subunit (rpb2), and the translation elongation factor 1-α (tef1) sequences. A multi gene genealogy based on these loci revealed that the closest relative is Ceriporiopsis (syn. Mycoacia) gilvescens. Even though such wood-destroying Basidiomycota are regularly encountered among the endophytic isolates after surface-disinfection of plant organs, the vast majority of the reported endophytic fungi belong to the Ascomycota. Nevertheless, the data available now allow for synonymizing Taxomyces with Ceriporiopsis, and the necessary new combination is made.
RESUMO
Bisporella as typically conceived is a genus of noticeable, bright yellow inoperculate discomycetes. This interpretation of the genus, however, is at odds with Bisporella pallescens, the current name of the type species of the genus; furthermore, the genus has been interpreted as including the unusual species Bisporella resinicola. By comparing morphological and molecular traits of species traditionally included in Bisporella, we show that the genus is polyphyletic, with many "typical" members of the genus belonging instead in Calycina in Pezizellaceae. Bisporella pallescens is conclusively linked with its asexual morph, Bispora antennata, and the genus Bisporella is abandoned as a later synonym of the monotypic genus Bispora (previously applied only to asexual fungi) and placed as sister to Hymenoscyphus in Helotiaceae. Bisporella resinicola is shown to represent an independent monotypic genus, Eustilbum, which so far is placed incertae sedis in Helotiales. Finally, "Bisporella" subpallida, like Bispora, belongs to Helotiaceae but is instead related to "Phaeohelotium" epiphyllum.
Assuntos
Filogenia , AscomicetosRESUMO
Closed cleistothecia-like ascomata have repeatedly evolved in non-related perithecioid and apothecioid lineages of lichenized and non-lichenized Ascomycota. The evolution of a closed, darkly pigmented ascoma that protects asci and ascospores is conceived as either an adaptation to harsh environmental conditions or a specialized dispersal strategy. Species with closed ascomata have mostly lost sterile hymenial elements (paraphyses) and the capacity to actively discharge ascospores. The class Leotiomycetes, one of the most speciose classes of Ascomycota, is mainly apothecioid, paraphysate, and possesses active ascospore discharge. Lineages with closed ascomata, and their morphological variants, have evolved independently in several families, such as Erysiphaceae, Myxotrichaceae, Rutstroemiaceae, etc. Thelebolales is a distinctive order in the Leotiomycetes class. It has two widespread families (Thelebolaceae, Pseudeurotiaceae) with mostly closed ascomata, evanescent asci, and thus passively dispersed ascospores. Within the order, closed ascomata dominate and a great diversity of peridia have evolved as adaptations to different dispersal strategies. The type genus, Thelebolus, is an exceptional case of ascomatal evolution within the order. Its species are the most diverse in functional traits, encompassing species with closed ascomata and evanescent asci, and species with open ascomata, active ascospore discharge, and paraphyses. Open ascomata were previously suggested as the ancestral state in the genus, these ascomata depend on mammals and birds as dispersal agents. In this scheme, species with closed ascomata, a lack of paraphyses, and passive ascospore discharge exhibit derived traits that evolved in adaptation to cold ecosystems. Here, we used morphological and phylogenetic methods, as well as the reconstruction of ancestral traits for ascomatal type, asci dehiscence, the presence or absence of paraphyses, and ascospore features to explore evolution within Thelebolales. We demonstrate the apothecial ancestry in Thelebolales and propose a new hypothesis about the evolution of the open ascomata in Thelebolus, involving a process of re-evolution where the active dispersal of ascospores appears independently twice within the order. We propose a new family, Holwayaceae, within Thelebolales, that retains the phenotypic features exhibited by species of Thelebolus, i.e., pigmented capitate paraphyses and active asci discharge with an opening limitation ring.
RESUMO
Since its resurrection, the resinicolous discomycete genus Sarea has been accepted as containing two species, one with black apothecia and pycnidia, and one with orange. We investigate this hypothesis using three ribosomal (nuITS, nuLSU, mtSSU) regions from and morphological examination of 70 specimens collected primarily in Europe and North America. The results of our analyses support separation of the traditional Sarea difformis s.lat. and Sarea resinae s.lat. into two distinct genera, Sarea and Zythia. Sarea as circumscribed is shown to conservatively comprise three phylospecies, with one corresponding to Sarea difformis s.str. and two, morphologically indistinguishable, corresponding to the newly combined Sarea coeloplata. Zythia is provisionally maintained as monotypic, containing only a genetically and morphologically variable Z. resinae. The new genus Atrozythia is erected for the new species A. klamathica. Arthrographis lignicola is placed in this genus on molecular grounds, expanding the concept of Sareomycetes by inclusion of a previously unknown type of asexual morph. Dating analyses using additional marker regions indicate the emergence of the Sareomycetes was roughly concurrent with the diversification of the genus Pinus, suggesting that this group of fungi emerged to exploit the newly-available resinous ecological niche supplied by Pinus or another, extinct group of conifers. Our phylogeographic studies also permitted us to study the introductions of these fungi to areas where they are not native, including Antarctica, Cape Verde, and New Zealand and are consistent with historical hypotheses of introduction.
RESUMO
Studies of Trochila (Leotiomycetes, Helotiales, Cenangiaceae) are scarce. Here, we describe two new species based on molecular phylogenetic data and morphology. Trochilabostonensis was collected at the Boston Harbor Islands National Recreation Area, Massachusetts. It was found on the stem of Asclepiassyriaca, representing the first report of any Trochila species from a plant host in the family Apocynaceae. Trochilaurediniophila is associated with the uredinia of the rust fungus Ceroteliumfici. It was discovered during a survey for rust hyperparasites conducted at the Arthur Fungarium, in a single sample from 1912 collected in Trinidad. Macro- and micromorphological descriptions, illustrations, and molecular phylogenetic analyses are presented. The two new species are placed in Trochila with high support in both our six-locus (SSU, ITS, LSU, rpb1, rpb2, tef1) and two-locus (ITS, LSU) phylogenetic reconstructions. In addition, two species are combined in Trochila: Trochilacolensoi (formerly placed in Pseudopeziza) and T.xishuangbanna (originally described as the only species in Calycellinopsis). This study reveals new host plant families, a new ecological strategy, and a new country record for the genus Trochila. Finally, our work emphasizes the importance of specimens deposited in biological collections such as fungaria.
RESUMO
In eukaryotes, proteins containing RNA Recognition Motifs (RRMs) are involved in many different RNA processing reactions, RNA transport, and mRNA decay. Kinetoplastids rely extensively on post-transcriptional mechanisms to control gene expression, so RRM domain proteins are expected to play a prominent role. We here describe the results of an RNA interference screen targeting 37 of the 72 RRM-domain proteins of Trypanosoma brucei. RNAi targeting 8 of the genes caused clear growth inhibition in bloodstream trypanosomes, and milder effects were seen for 9 more genes. The small, single-RRM protein TbRBP3 specifically associated with 10 mRNAs in trypanosome lysates, but RBP3 depletion did not affect the transcriptome.
Assuntos
Proteínas de Protozoários/metabolismo , Interferência de RNA , Proteínas de Ligação a RNA/metabolismo , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/metabolismo , Animais , Humanos , Estrutura Terciária de Proteína , Transporte Proteico , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , RNA de Protozoário/genética , RNA de Protozoário/metabolismo , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/genética , Trypanosoma brucei brucei/química , Tripanossomíase Africana/parasitologiaRESUMO
Triblidiaceae is a family of uncommonly encountered, non-lichenized discomycetes. A recent classification circumscribed the family to include Triblidium (4 spp. and 1 subsp.), Huangshania (2 spp.) and Pseudographis (2 spp. and 1 var.). The apothecia of these fungi are persistent and drought-tolerant; they possess stromatic, highly melanized covering layers that open and close with fluctuations of humidity. Triblidialean fungi occur primarily on the bark of Quercus, Pinaceae and Ericaceae, presumably as saprobes. Though the type species of Huangshania is from China, these fungi are mostly known from collections originating from Western Hemisphere temperate and boreal forests. The higher-rank classification of triblidialean fungi has been in flux due in part to an overemphasis on ascospore morphology. Muriform ascospores are observed in species of Triblidium and in Pseudographiselatina. An intense, dark blue/purple ascospore wall reaction in iodine-based reagents is observed in species of Pseudographis. These morphologies have led, in part, to these genera being shuffled among unrelated taxa in Hysteriaceae (Dothideomycetes, Hysteriales) and Graphidaceae (Lecanoromycetes, Ostropales). Triblidiaceae has been placed within the monofamilial order Triblidiales (affinity Lecanoromycetes). Here, we demonstrate with a three-gene phylogenetic approach that triblidialean fungi are related to taxa in Rhytismatales (Leotiomycetes). We synonymize Triblidiales under Rhytismatales and emend Triblidiaceae to include Triblidium and Huangshania, with Pseudographis placed within Rhytismataceae. A history of Triblidiaceae is provided along with a description of the emended family. We discuss how the inclusion of triblidialean fungi in Rhytismatales brings some rarely observed or even unique ascospore morphologies to the order and to Leotiomycetes.
RESUMO
Fungi in the class Leotiomycetes are ecologically diverse, including mycorrhizas, endophytes of roots and leaves, plant pathogens, aquatic and aero-aquatic hyphomycetes, mammalian pathogens, and saprobes. These fungi are commonly detected in cultures from diseased tissue and from environmental DNA extracts. The identification of specimens from such character-poor samples increasingly relies on DNA sequencing. However, the current classification of Leotiomycetes is still largely based on morphologically defined taxa, especially at higher taxonomic levels. Consequently, the formal Leotiomycetes classification is frequently poorly congruent with the relationships suggested by DNA sequencing studies. Previous class-wide phylogenies of Leotiomycetes have been based on ribosomal DNA markers, with most of the published multi-gene studies being focussed on particular genera or families. In this paper we collate data available from specimens representing both sexual and asexual morphs from across the genetic breadth of the class, with a focus on generic type species, to present a phylogeny based on up to 15 concatenated genes across 279 specimens. Included in the dataset are genes that were extracted from 72 of the genomes available for the class, including 10 new genomes released with this study. To test the statistical support for the deepest branches in the phylogeny, an additional phylogeny based on 3156 genes from 51 selected genomes is also presented. To fill some of the taxonomic gaps in the 15-gene phylogeny, we further present an ITS gene tree, particularly targeting ex-type specimens of generic type species. A small number of novel taxa are proposed: Marthamycetales ord. nov., and Drepanopezizaceae and Mniaeciaceae fams. nov. The formal taxonomic changes are limited in part because of the ad hoc nature of taxon and specimen selection, based purely on the availability of data. The phylogeny constitutes a framework for enabling future taxonomically targeted studies using deliberate specimen selection. Such studies will ideally include designation of epitypes for the type species of those genera for which DNA is not able to be extracted from the original type specimen, and consideration of morphological characters whenever genetically defined clades are recognized as formal taxa within a classification.
RESUMO
The new genus Aotearoamyces is proposed to accommodate a single species that was repeatedly collected on fallen wood in Nothofagaceae forests of New Zealand and was previously misidentified as a Claussenomyces species. This monotypic genus belongs to Tympanidaceae, a recently erected family in Phacidiales. Aotearoamyces is differentiated from other Tympanidaceae by phragmospores that do not form conidia either in or outside the asci, an exciple of textura intricata with hyphae widely spaced and strongly gelatinized (plectenchyma), and apically flexuous, partly helicoid paraphyses. The asexual morph was studied in pure culture. Phylogenetic analyses of combined SSU, ITS and LSU sequences strongly support a sister relationship between the sexually typified Aotearoamyces and the asexually typified "Collophorina" paarla characterized morphologically by forming endoconidia, a feature not found in the genetically distinct type species of Collophorina. Based on our molecular results, we place the genus Epithamnolia in the Mniaecia lineage within Phacidiales.
RESUMO
In this chapter, we explain different strategies to analyze the extracellular Hedgehog (Hh) morphogen distribution and Hh intracellular trafficking by immunohistochemistry techniques. For this purpose, it has been very useful to have a transgenic fly line that expresses a Hh-green fluorescent protein (GFP) fusion protein. These flies can be used to study the way Hh spreads through the anterior compartment where it signals, and analyze in detail how Hh is internalized by its receptor Patched. In addition, this Hh-GFP fusion made without lipid modifications (cholesterol or palmitic acid) can be used to investigate the function of these lipids on Hh in terms of spreading, internalization, and signaling abilities.
Assuntos
Espaço Extracelular/metabolismo , Proteínas Hedgehog/metabolismo , Imuno-Histoquímica/métodos , Espaço Intracelular/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Animais , Animais Geneticamente Modificados , Drosophila , Endocitose , Proteínas de Fluorescência Verde/metabolismo , Microscopia Confocal , Transporte Proteico , Solubilidade , Coloração e Rotulagem , Asas de Animais/anatomia & histologia , Asas de Animais/citologiaRESUMO
Introducción: El síndrome de desmielinización osmótica es una entidad clínica la cual supone un reto diagnóstico por su curso en muchos casos silentes y por su cuadro clínico que se presenta típicamente de manera tardía. Se describen dos tipos de desmielinización osmótica que pueden presentarse de manera aislada o simultánea: la mielinosis central pontina y la mielinosis extrapontina. Caso clínico: femenina de 21 años sin antecedentes personales con episodio convulsivo tónico clónico por primera vez en su vida. Se le encuentra a su ingreso un nivel de sodio sérico disminuido, razón por la cual se inicia la corrección intravenosa del mismo. Cursó con cefaleas persistentes y vómitos a las 48 horas posterior a la corrección del sodio, y se realizó una resonancia magnética cerebral que evidenció datos de mielinosis extrapontina. Conclusión: La corrección rápida de los niveles de sodio se asocia a la posibilidad de desarrollar mielinosis pontina. La precaución en la corrección de la hiponatremia es la piedra angular para prevenir el desarrollo de esta condición. (provisto por Infomedic International)
Introduction: Osmotic demyelination syndrome is a clinical entity which poses a diagnostic challenge because of its often-silent course and its clinical picture which typically presents late. We describe two types of osmotic demyelination that can occur in isolation or simultaneously: central pontine myelinosis and extrapontine myelinosis. Case report: 21-year-old female with no personal history with tonic-clonic seizure episode for the first time in her life. On admission she was found to have a decreased serum sodium level, for which reason intravenous sodium correction was started. He presented with persistent headaches and vomiting 48 hours after sodium correction, and a brain MRI was performed, which showed evidence of extrapontine myelinosis. Conclusion: Rapid correction of sodium levels is associated with the possibility of developing pontine myelinosis. Caution in correcting hyponatremia is the cornerstone in preventing the development of this condition. (provided by Infomedic International)
RESUMO
The salivarian trypanosome Trypanosoma brucei infects mammals and is transmitted by tsetse flies. The mammalian 'bloodstream form' trypanosome has a variant surface glycoprotein coat and relies on glycolysis while the procyclic form from tsetse flies has EP protein on the surface and has a more developed mitochondrion. We show here that the mRNA for the procyclic-specific cytosolic phosphoglycerate kinase PGKB, like that for EP proteins, contains a regulatory AU-rich element (ARE) that destabilises the mRNA in bloodstream forms. The human HuR protein binds to, and stabilises, mammalian mRNAs containing AREs. Expression of HuR in bloodstream-form trypanosomes resulted in growth arrest and in stabilisation of the EP, PGKB and pyruvate, phosphate dikinase mRNAs, while three bloodstream-specific mRNAs were reduced in abundance. The synthesis and abundance of unregulated mRNAs and proteins were unaffected. Our results suggest that regulation of mRNA stability by AREs arose early in eukaryotic evolution.
Assuntos
Regiões 3' não Traduzidas , Antígenos de Superfície , Estabilidade de RNA , RNA de Protozoário/metabolismo , Proteínas de Ligação a RNA/genética , Trypanosoma brucei brucei/genética , Adenina/análise , Animais , Sequência de Bases , Proteínas ELAV , Proteína Semelhante a ELAV 1 , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Dados de Sequência Molecular , Fosfoglicerato Quinase/genética , Fosfoglicerato Quinase/metabolismo , Proteínas de Protozoários/biossíntese , RNA Mensageiro/química , RNA Mensageiro/metabolismo , RNA de Protozoário/química , Proteínas de Ligação a RNA/metabolismo , Sequências Reguladoras de Ácido Nucleico , Trypanosoma brucei brucei/crescimento & desenvolvimento , Trypanosoma brucei brucei/metabolismo , Uracila/análiseRESUMO
The cell-cycle-dependent expression of the four core histones (H2A, H2B, H3 and H4) has been studied in the protozoan parasite Leishmania infantum. For that purpose, the cell cycle was arrested by incubation of promastigotes with the DNA synthesis inhibitor hydroxyurea, which induced an accumulation of cells stalled in G1 phase. Hydroxyurea release resulted in a semi-synchronous entry into the cell cycle, as determined by flow cytometry. The steady-state levels of histone mRNAs in the G1, S and G2/M phases were found to be constant along the cell cycle. However, the levels of histone synthesis increased when parasites enter the S phase, in agreement with previous results showing that histone synthesis in Leishmania is tightly coupled with DNA replication. In addition, we analysed the distribution of histone mRNAs on polyribosomes at different stages of the cell cycle by separation of cytoplasmic RNAs in sucrose gradients. Remarkably, a drastic change in the polysome profiles of histone mRNAs was observed during the progression from G1 to S phase. Thus, in the S phase, histone mRNAs are present in ribosome-bound fractions, but in the G1 phase, the histone transcripts are exclusively found in the ribosome-free fractions. These results support a regulatory model in which the cell-cycle-regulated synthesis of histones in Leishmania is controlled through a reversible interaction between translational repressors and histone mRNAs.
Assuntos
Ciclo Celular/fisiologia , Histonas/biossíntese , Histonas/genética , Leishmania infantum/genética , Leishmania infantum/metabolismo , Biossíntese de Proteínas , RNA de Protozoário/metabolismo , Animais , Ciclo Celular/efeitos dos fármacos , Centrifugação com Gradiente de Concentração , Replicação do DNA/efeitos dos fármacos , DNA de Protozoário/análise , DNA de Protozoário/genética , Fase G1/efeitos dos fármacos , Proteínas de Choque Térmico HSP70/biossíntese , Proteínas de Choque Térmico HSP70/genética , Hidroxiureia/farmacologia , Leishmania infantum/efeitos dos fármacos , Polirribossomos/efeitos dos fármacos , Polirribossomos/genética , Proteínas de Protozoários/biossíntese , Proteínas de Protozoários/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Protozoário/genética , Fase S/efeitos dos fármacosRESUMO
BACKGROUND: Exposure of Leishmania promastigotes to the temperature of their mammalian hosts results in the induction of a typical heat shock response. It has been suggested that heat shock proteins play an important role in parasite survival and differentiation. RESULTS: Here we report the studies on the expression of the heat shock protein 83 (HSP83) genes of Leishmania infantum. Confirming previous observations for other Leishmania species, we found that the L. infantum HSP83 transcripts also show a temperature-dependent accumulation that is controlled by a post-transcriptional mechanism involving sequences located in the 3'-untranslated region (3'-UTR). However, contrary to that described for L. amazonensis, the accumulation of the HSP83 transcripts in L. infantum is dependent on active protein synthesis. The translation of HSP83 transcripts is enhanced during heat shock and, as first described in L. amazonensis, we show that the 3'-UTR of the L. infantum HSP83 gene is essential for this translational control. Measurement of the steady-state levels of HSP83 transcripts along the promastigote-to-amastigote differentiation evidenced a specific profile of HSP83 RNAs: after an initial accumulation of HSP83 transcripts observed short after (2 h) incubation in the differentiation conditions, the amount of HSP83 RNA decreased to a steady-state level lower than in undifferentiated promastigotes. We show that this transient accumulation is linked to the presence of the 3'-UTR and flanking regions. Again, an 8-fold increase in translation of the HSP83 transcripts is observed short after the initiation of the axenic differentiation, but it is not sustained after 9 h. CONCLUSIONS: This transient expression of HSP83 genes could be relevant for the differentiation of Leishmania, and the underlying regulatory mechanism may be part of the developmental program of this parasite.
Assuntos
Diferenciação Celular/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Proteínas de Choque Térmico/genética , Leishmania infantum/genética , Biossíntese de Proteínas/fisiologia , Estabilidade de RNA/fisiologia , Temperatura , Regiões 3' não Traduzidas/genética , Regiões 3' não Traduzidas/fisiologia , Animais , DNA de Protozoário/genética , DNA de Protozoário/fisiologia , Genes Reporter/fisiologia , Proteínas de Protozoários/genética , RNA Mensageiro/metabolismoRESUMO
Los protocolos ERAS por sus siglas en inglés (Enhanced Recovery after Surgery) se centran en reducir las complicaciones postoperatorias y la respuesta al estrés, optimizando la recuperación postoperatoria, dentro de las intervenciones el inicio temprano de la alimentación ha demostrado ser eficaz para reducir la morbilidad, los costos generales y la satisfacción del paciente. El presente estudio, revisión bibliográfica, plantea la importancia de tomar este tipo de medidas en pacientes con derivación biliodigestiva en el Hospital Médico Quirúrgico del Instituto Salvadoreños del Seguro Social. Cuantificar este aspecto en el Hospital Médico Quirúrgico del ISSS permitirá profundizar en estudios clínicos o analíticos para posteriormente implementar y protocolizar la intervención