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1.
Environ Microbiol Rep ; 11(6): 848-854, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31600852

RESUMO

Phycobilisomes (PBS) are large water-soluble membrane-associated complexes in cyanobacteria and some chloroplasts that serve as light-harvesting antennae for the photosynthetic apparatus. When deplete of nitrogen or sulphur, cyanobacteria readily degrade their phycobilisomes allowing the cell to replenish these vanishing nutrients. The key regulator in the degradation process is NblA, a small protein (∼6 kDa), which recruits proteases to the PBS. It was discovered previously that not only do cyanobacteria possess nblA genes but also that they are encoded by genomes of some freshwater cyanophages. A recent study, using assemblies from oceanic metagenomes, revealed genomes of a novel uncultured marine cyanophage lineage, representatives of which contain genes coding for the PBS degradation protein. Here, we examined the functionality of nblA-like genes from these marine cyanophages by testing them in a freshwater model cyanobacterial nblA knockout. One of the viral NblA variants could complement the non-bleaching phenotype and restore PBS degradation. Our findings reveal a functional NblA from a novel marine cyanophage lineage. Furthermore, we shed new light on the distribution of nblA genes in cyanobacteria and cyanophages.


Assuntos
Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Bacteriófagos/enzimologia , Bacteriófagos/genética , Cianobactérias/virologia , Proteínas Virais/genética , Cianobactérias/genética , Teste de Complementação Genética , Metagenoma , Ficobilissomas/metabolismo , Proteólise , Água do Mar/virologia
2.
Nat Commun ; 10(1): 3315, 2019 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-31346176

RESUMO

Channelrhodopsins (ChRs) are algal light-gated ion channels widely used as optogenetic tools for manipulating neuronal activity. ChRs desensitize under continuous bright-light illumination, resulting in a significant decline of photocurrents. Here we describe a metagenomically identified family of phylogenetically distinct anion-conducting ChRs (designated MerMAIDs). MerMAIDs almost completely desensitize during continuous illumination due to accumulation of a late non-conducting photointermediate that disrupts the ion permeation pathway. MerMAID desensitization can be fully explained by a single photocycle in which a long-lived desensitized state follows the short-lived conducting state. A conserved cysteine is the critical factor in desensitization, as its mutation results in recovery of large stationary photocurrents. The rapid desensitization of MerMAIDs enables their use as optogenetic silencers for transient suppression of individual action potentials without affecting subsequent spiking during continuous illumination. Our results could facilitate the development of optogenetic tools from metagenomic databases and enhance general understanding of ChR function.


Assuntos
Ânions/metabolismo , Bactérias/genética , Channelrhodopsins/genética , Família Multigênica , Vírus/genética , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Channelrhodopsins/química , Channelrhodopsins/metabolismo , Humanos , Cinética , Luz , Metagenoma , Neurônios/metabolismo , Optogenética , Filogenia , Água do Mar/microbiologia , Água do Mar/virologia , Proteínas Virais/genética , Proteínas Virais/metabolismo , Vírus/classificação , Vírus/isolamento & purificação , Vírus/metabolismo
3.
J Equine Vet Sci ; 77: 36-42, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31133314

RESUMO

The objective of the study was to conduct a review of the pharmacological regulation and pharmacokinetic parameters of firocoxib when administered orally or intravenously in horses. A search for literature was done in SCOPUS and PubMed for studies that had to evaluate the pharmacological regulation as well as the pharmacokinetic parameters of firocoxib when administered in horses. The nonsteroidal anti-inflammatory drugs have analgesic, anti-inflammatory, antipyretics, and antiendotoxic effects. The newly developed is selective to COX2 characterized by less adverse effects in veterinary patients when administered at the recommended doses and do not exceed the established prescribed time. Firocoxib is authorized by the Food and Drug Administration for the treatment of pain in horses, whereas for humans, there is still no approval. Controversy has arisen because the administration of the same pharmaceutical presentation in horses and dogs has pharmacokinetic differences between animal species. However, special attention must be paid to pharmacokinetic differences between species like in horses and dogs. In the case of the horse, the dosage is 0.1 mg/kg in single dose or up to 14 days in oral paste formulation and can keep maintained on the same concentration for a period of 7-14 days in oral tablet formulation. Thorough knowledge of pharmacological regulations and pharmacokinetic parameters, it allows the posology and effective application of firocoxib in pathologies associated with chronic pain, avoiding the indiscriminate use by owners and in some cases veterinarians, thus reducing the negative impacts on horse's health.

4.
Environ Microbiol Rep ; 11(4): 598-604, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31125500

RESUMO

Marine cyanobacteria are important contributors to primary production in the ocean and their viruses (cyanophages) affect the ocean microbial communities. Despite reports of lysogeny in marine cyanobacteria, a genome sequence of such temperate cyanophages remains unknown although genomic analysis indicate potential for lysogeny in certain marine cyanophages. Using assemblies from Red Sea and Tara Oceans metagenomes, we recovered genomes of a novel uncultured marine cyanophage lineage, which contain, in addition to common cyanophage genes, a phycobilisome degradation protein NblA, an integrase and a split DNA polymerase. The DNA polymerase forms a monophyletic clade with a DNA polymerase from a genomic island in Synechococcus WH8016. The island contains a relic prophage that does not resemble any previously reported cyanophage but shares several genes with the newly identified cyanophages reported here. Metagenomic recruitment indicates that the novel cyanophages are widespread, albeit at low abundance. Here, we describe a novel potentially lysogenic cyanophage family, their abundance and distribution in the marine environment.


Assuntos
Bacteriófagos/genética , Lisogenia/genética , Prófagos/genética , Água do Mar/virologia , Synechococcus/virologia , Bacteriófagos/classificação , Bacteriófagos/isolamento & purificação , Sequência de Bases , Genoma Viral , Ilhas Genômicas/genética , Metagenoma , Oceanos e Mares , Filogenia , Prófagos/classificação , Prófagos/isolamento & purificação , Synechococcus/genética , Proteínas Virais/genética
5.
Appl Opt ; 58(4): 752-763, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30874116

RESUMO

In this work, we present a technique for quantitatively assessing the optical quality of a parabolic trough solar collector. The presented method is an adaptation of the null-screen technology, a collection of processes that retrieve information from the reflection of a known object from the surface and then use that information to reconstruct the surface's normal vectors. Via numerical simulations, it is shown that the precision attainable by this method is up to 0.068 mrad, depending on the source of systematical error. In this study we only consider displacements of the physical null-screen as sources of error.

6.
Acta neurol. colomb ; 35(1): 36-39, ene.-mar. 2019. graf
Artigo em Espanhol | LILACS | ID: biblio-989196

RESUMO

RESUMEN La parálisis pseudoperiférica es una presentación infrecuente del ataque cerebrovascular (ACV) isquémico, que suele llevar a un diagnóstico erróneo de patología de nervio periférico. Se caracteriza por una presentación clínica consistente en paresia de la mano o de un grupo de dedos y alteración de la sensibilidad que puede simular el compromiso de un nervio periférico. Se reporta el caso clínico de un paciente que cursó con parálisis pseudoperiférica, con compromiso motor predominantemente cubital asociado a hipoestesia multimodal en la región hipotenar, lo cual ilustrando la dificultad de la localización topográfica para explicar el compromiso motor y sensitivo por un síndrome mononeuropático, troncular, radicular o medular. Se resalta la importancia de una adecuada evaluación semiológica, que permita hacer aproximaciones diagnósticas acertadas para dar un manejo adecuado de acuerdo con el estudio topográfico en las patologías neurológicas.


SUMMARY Pseudo-peripheral palsy is an infrequent presentation of ischemic stroke, which often leads to a misdiagnosis of peripheral nerve pathology. It is characterized by palsy of the hand or a group of fingers and altered sensitivity which can simulate peripheral nerve damage. We report a case of a patient who had pseudo-peripheral palsy with predominantly ulnar motor involvement, associated with multimodal hypoesthesia in the hypothenar region; illustrating the difficulty of topographic localization to explain motor and sensory involvement by a mononeuropathic, radicular or spinal syndrome. We highlight the importance of an adequate semiological evaluation to accurately diagnose and manage these pathologies.


Assuntos
Paralisia , Acidente Vascular Cerebral , Diagnóstico Diferencial , Córtex Motor
7.
Int. j. psychol. psychol. ther. (Ed. impr.) ; 19(1): 5-14, mar. 2019. tab
Artigo em Inglês | IBECS | ID: ibc-183818

RESUMO

Previous research has analyzed the effectiveness of a single session intervention of Behavioral Activation (BA) for reducing depressive symptoms, however, it is important to replicate findings in different populations. The aim of this study was to determine the effectiveness of a single session intervention protocol of BA in college students with depressive symptomatology. The study was experimental pretest posttest with reference group in waiting list (N= 60). Students who scored more than 36 points in the Zung Self-Rating Depression Scale (SDS) were selected and were randomly distributed to the reference group or experimental group. The results showed a remarkable decrease of depressive symptomatology in experimental group students compared to control group and it was found that the effect size of the treatment was 0.74, which contributes to the empirical evidence about BA especially regarding college population


No disponible


Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto Jovem , Adulto , Depressão/terapia , Psicoterapia Breve/métodos , Terapia Cognitivo-Comportamental/métodos , Avaliação de Resultado de Intervenções Terapêuticas , Estudantes/psicologia , Estudos de Casos e Controles , Psicometria/instrumentação
8.
Environ Microbiol Rep ; 11(3): 419-424, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30618066

RESUMO

Microbial heliorhodopsins are a new type of rhodopsins, currently believed to engage in light sensing, with an opposite membrane topology compared to type-1 and type-2 rhodopsins. We determined heliorhodopsins presence/absence is monoderms and diderms representatives from the Tara Oceans and freshwater metagenomes as well as metagenome assembled genome collections. Heliorhodopsins are absent in diderms, confirming our previous observations in cultured Proteobacteria. We do not rule out the possibility that heliorhodopsins serve as light sensors. However, this does not easily explain their absence from diderms. Based on these observations, we speculate on the putative role of heliorhodopsins in light-driven transport of amphiphilic molecules.


Assuntos
Bactérias Gram-Negativas/genética , Rodopsinas Sensoriais/genética , Água Doce/microbiologia , Água Doce/virologia , Bactérias Gram-Negativas/classificação , Metagenoma , Modelos Biológicos , Oceanos e Mares , Fases de Leitura Aberta , Água do Mar/microbiologia , Água do Mar/virologia , Rodopsinas Sensoriais/metabolismo
9.
Nature ; 558(7711): 595-599, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29925949

RESUMO

Many organisms capture or sense sunlight using rhodopsin pigments1,2, which are integral membrane proteins that bind retinal chromophores. Rhodopsins comprise two distinct protein families 1 , type-1 (microbial rhodopsins) and type-2 (animal rhodopsins). The two families share similar topologies and contain seven transmembrane helices that form a pocket in which retinal is linked covalently as a protonated Schiff base to a lysine at the seventh transmembrane helix2,3. Type-1 and type-2 rhodopsins show little or no sequence similarity to each other, as a consequence of extensive divergence from a common ancestor or convergent evolution of similar structures 1 . Here we report a previously unknown and diverse family of rhodopsins-which we term the heliorhodopsins-that we identified using functional metagenomics and that are distantly related to type-1 rhodopsins. Heliorhodopsins are embedded in the membrane with their N termini facing the cell cytoplasm, an orientation that is opposite to that of type-1 or type-2 rhodopsins. Heliorhodopsins show photocycles that are longer than one second, which is suggestive of light-sensory activity. Heliorhodopsin photocycles accompany retinal isomerization and proton transfer, as in type-1 and type-2 rhodopsins, but protons are never released from the protein, even transiently. Heliorhodopsins are abundant and distributed globally; we detected them in Archaea, Bacteria, Eukarya and their viruses. Our findings reveal a previously unknown family of light-sensing rhodopsins that are widespread in the microbial world.


Assuntos
Metagenômica , Rodopsina/análise , Rodopsina/classificação , Sequência de Aminoácidos , Eucariotos/química , Evolução Molecular , Rodopsina/química , Rodopsina/efeitos da radiação , Rodopsinas Microbianas/análise , Rodopsinas Microbianas/química , Rodopsinas Microbianas/classificação , Rodopsinas Microbianas/efeitos da radiação
10.
ISME J ; 12(2): 343-355, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29028002

RESUMO

Cyanobacteria are among the most abundant photosynthetic organisms in the oceans; viruses infecting cyanobacteria (cyanophages) can alter cyanobacterial populations, and therefore affect the local food web and global biochemical cycles. These phages carry auxiliary metabolic genes (AMGs), which rewire various metabolic pathways in the infected host cell, resulting in increased phage fitness. Coping with stress resulting from photodamage appears to be a central necessity of cyanophages, yet the overall mechanism is poorly understood. Here we report a novel, widespread cyanophage AMG, encoding a fatty acid desaturase (FAD), found in two genotypes with distinct geographical distribution. FADs are capable of modulating the fluidity of the host's membrane, a fundamental stress response in living cells. We show that both viral FAD (vFAD) families are Δ9 lipid desaturases, catalyzing the desaturation at carbon 9 in C16 fatty acid chains. In addition, we present a comprehensive fatty acid profiling for marine cyanobacteria, which suggests a unique desaturation pathway of medium- to long-chain fatty acids no longer than C16, in accordance with the vFAD activity. Our findings suggest that cyanophages are capable of fiddling with the infected host's membranes, possibly leading to increased photoprotection and potentially enhancing viral-encoded photosynthetic proteins, resulting in a new viral metabolic network.


Assuntos
Bacteriófagos/enzimologia , Cianobactérias/virologia , Ácidos Graxos/química , Lipídeos/química , Oceanos e Mares , Fotossíntese , Proteínas Virais/genética , Motivos de Aminoácidos , Bacteriófagos/genética , Mapeamento Cromossômico , Biologia Computacional , Mapeamento de Sequências Contíguas , Replicação do DNA , Genótipo , Histidina , Filogenia , Saccharomyces cerevisiae/metabolismo , Microbiologia da Água
11.
Value Health Reg Issues ; 14: 15-19, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29254536

RESUMO

OBJECTIVES: To estimate productivity losses due to absenteeism and presenteeism and their determinants in patients with depression from five Colombian cities. METHODS: We used data from a multicenter, mixed-methods study of adult patients diagnosed with major depressive disorder or double depression (major depressive disorder plus dysthymia) during 2010. The World Health Organization's Health and Work Performance Questionnaire was used to assess absenteeism and presenteeism. We explored the determinants of productivity losses using a two-part model. We also used a costing model to calculate the corresponding monetary losses. RESULTS: We analyzed data from 107 patients employed in the last 4 weeks. Absenteeism was reported by 70% of patients; presenteeism was reported by all but one. Half of the patients reported a level of performance at work at least 50% below usual. Average number of hours per month lost to absenteeism and presenteeism was 43 and 51, respectively. The probability of any absenteeism was 17 percentage points lower in patients rating their mental health favorably compared with those rating it poorly (standard error [SE] 0.09; P < 0.10) and 19 percentage points higher in patients with at least one comorbidity compared with patients with none (SE 0.10; P < 0.10). All other covariates showed no significant associations on hours lost to absenteeism. Patients with favorable mental health self-ratings had 16.4 fewer hours per month of presenteeism compared with those with poor self-ratings (SE 4.52; P < 0.01). The 2015 monetary value of productivity losses amounted to US $840 million. CONCLUSIONS: This study in a middle-income country confirms the high economic burden of depression. Health policies and workplace interventions ensuring adequate diagnosis and treatment of depression are recommended.


Assuntos
Absenteísmo , Transtorno Depressivo Maior , Eficiência , Presenteísmo/estatística & dados numéricos , Local de Trabalho , Adulto , Colômbia , Transtorno Depressivo Maior/economia , Feminino , Humanos , Masculino , Saúde Mental , Inquéritos e Questionários , Desempenho Profissional/estatística & dados numéricos , Local de Trabalho/economia , Local de Trabalho/estatística & dados numéricos
12.
Nat Microbiol ; 2(10): 1350-1357, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28785078

RESUMO

Cyanobacteria are important contributors to primary production in the open oceans. Over the past decade, various photosynthesis-related genes have been found in viruses that infect cyanobacteria (cyanophages). Although photosystem II (PSII) genes are common in both cultured cyanophages and environmental samples 1-4 , viral photosystem I (vPSI) genes have so far only been detected in environmental samples 5,6 . Here, we have used a targeted strategy to isolate a cyanophage from the tropical Pacific Ocean that carries a PSI gene cassette with seven distinct PSI genes (psaJF, C, A, B, K, E, D) as well as two PSII genes (psbA, D). This cyanophage, P-TIM68, belongs to the T4-like myoviruses, has a prolate capsid, a long contractile tail and infects Prochlorococcus sp. strain MIT9515. Phage photosynthesis genes from both photosystems are expressed during infection, and the resultant proteins are incorporated into membranes of the infected host. Moreover, photosynthetic capacity in the cell is maintained throughout the infection cycle with enhancement of cyclic electron flow around PSI. Analysis of metagenomic data from the Tara Oceans expedition 7 shows that phages carrying PSI gene cassettes are abundant in the tropical Pacific Ocean, composing up to 28% of T4-like cyanomyophages. They are also present in the tropical Indian and Atlantic Oceans. P-TIM68 populations, specifically, compose on average 22% of the PSI-gene-cassette carrying phages. Our results suggest that cyanophages carrying PSI and PSII genes are likely to maintain and even manipulate photosynthesis during infection of their Prochlorococcus hosts in the tropical oceans.


Assuntos
Transporte de Elétrons/genética , Myoviridae/genética , Complexo de Proteína do Fotossistema I/genética , Complexo de Proteína do Fotossistema II/genética , Prochlorococcus/genética , Prochlorococcus/virologia , Oceano Atlântico , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos/genética , Genes Virais/genética , Genoma Viral/genética , Myoviridae/classificação , Myoviridae/patogenicidade , Myoviridae/ultraestrutura , Oceano Pacífico , Fotossíntese/genética , Filogenia , Proteínas Virais/genética
13.
ACS Appl Mater Interfaces ; 9(35): 29654-29659, 2017 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-28805366

RESUMO

Optimization of the interface between the electron transport layer (ETL) and the hybrid perovskite is crucial to achieve high-performance perovskite solar cell (PSC) devices. Fullerene-based compounds have attracted attention as modifiers on the surface properties of TiO2, the archetypal ETL in regular n-i-p PSCs. However, the partial solubility of fullerenes in the aprotic solvents used for perovskite deposition hinders its application to low-temperature solution-processed PSCs. In this work, we introduce a new method for fullerene modification of TiO2 layers derived from nanoparticles (NPs) inks. Atomic force microscopy characterization reveals that the resulting ETL is a network of TiO2-NPs interconnected by fullerenes. Interestingly, this surface modification enhances the bottom interface of the perovskite by improving the charge transfer as well as the top perovskite interface by reducing surface trap states enhancing the contact with the p-type buffer layer. As a result, rigid PSCs reached a 17.2% power conversion efficiency (PCE), while flexible PSCs exhibited a remarkable stabilized PCE of 12.2% demonstrating the potential application of this approach for further scale-up of PSC devices.

14.
Nanoscale ; 9(27): 9440-9446, 2017 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-28660942

RESUMO

Effective control of the interface between the metal cathode and the electron transport layer (ETL) is critical for achieving high performance p-i-n planar heterojunction perovskite solar cells (PSCs). Several organic molecules have been explored as interlayers between the silver (Ag) electrode and the ETL for the improvement in the photovoltaic conversion efficiency (PCE) of p-i-n planar PSCs. However, the role of these organic molecules in the charge transfer at the metal/ETL interface and the chemical degradation processes of PSCs has not yet been fully understood. In this work, we systematically explore the effects of the interfacial modification of the Ag/ETL interface on PSCs using rhodamine 101 as a model molecule. By the insertion of rhodamine 101 as an interlayer between Ag and fullerene derivatives (PC60BM and PC70BM) ETLs improve the PCE as well as the stability of p-i-n planar PSCs. Atomic force microscopy (AFM) characterization reveals that rhodamine passivates the defects at the PCBM layer and reduces the band bending at the PCBM surface. In consequence, charge transfer from the PCBM towards the Ag electrode is enhanced leading to an increased fill factor (FF) resulting in a PCE up to 16.6%. Moreover, rhodamine acts as a permeation barrier hindering the penetration of moisture towards the perovskite layer as well as preventing the chemical interaction of perovskite with the Ag electrode. Interestingly, the work function of the metal cathode remains more stable due to the rhodamine incorporation. Consequently, a better alignment between the quasi-Fermi level of PCBM and the Ag work function is achieved minimizing the energy barrier for charge extraction. This work contributes to reveal the relevance of proper interfacial engineering at the metal-cathode/organic-semiconductor interface.

15.
Curr Biol ; 27(9): 1362-1368, 2017 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-28457865

RESUMO

Marine group II Euryarchaeota (MG-II) are among the most abundant microbes in oceanic surface waters [1-4]. So far, however, representatives of MG-II have not been cultivated, and no viruses infecting these organisms have been described. Here, we present complete genomes for three distinct groups of viruses assembled from metagenomic sequence datasets highly enriched for MG-II. These novel viruses, which we denote magroviruses, possess double-stranded DNA genomes of 65 to 100 kilobases in size that encode a structural module characteristic of head-tailed viruses and, unusually for archaeal and bacterial viruses, a nearly complete replication apparatus of apparent archaeal origin. The newly identified magroviruses are widespread and abundant and therefore are likely to be major ecological agents.


Assuntos
Vírus de Archaea/classificação , Vírus de Archaea/fisiologia , Euryarchaeota/virologia , Metagenômica , Vírus de Archaea/genética , DNA Polimerase Dirigida por DNA/genética , DNA Polimerase Dirigida por DNA/metabolismo , Genoma Viral , Oceanos e Mares , Filogenia , Proteínas Virais/genética , Proteínas Virais/metabolismo , Integração Viral , Replicação Viral
17.
Rev. colomb. cir ; 32(1): 61-67, 20170000. fig
Artigo em Espanhol | LILACS | ID: biblio-884622

RESUMO

La arteria ciática persistente es una anomalía congénita poco frecuente que puede cursar asintomática o manifestarse como una masa pulsátil en el glúteo, una isquemia aguda de la extremidad o un dolor ciático. Frecuentemente, presenta degeneración aneurismática y complicaciones relacionadas con el aneurisma, como en el caso que se presenta. No hay consenso sobre el mejor tratamiento; sin embargo, la mayoría de los autores recomienda el tratamiento quirúrgico, conservando la arteria, debido a que en el 40 % de los casos es el vaso principal de la extremidad. Se presenta el caso de una paciente con un aneurisma de la arteria ciática persistente, que consultó por isquemia aguda de la extremidad y fue tratada en forma exitosa con un abordaje combinado, endovascular y quirúrgico


The persistent sciatic artery (PCA) is a rare congenital anomaly that may present asymptomatic or as a pulsating mass in the buttock, acute limb ischemia or sciatic pain. It often presents aneurysmatic degeneration and aneurysmrelated complications, like in the case hereby presented. There is no consensus on the best management, but most authors recommend surgical treatment, preserving the artery because in 40% of cases it is the main vessel of the limb. We had a patient who consulted with an aneurysm of the PCA and acute limb ischemia and who was treated as a combined successful endovascular and surgical approach


Assuntos
Humanos , Aneurisma , Isquemia , Transplantes
18.
Environ Microbiol ; 17(12): 5100-8, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26310718

RESUMO

Marine photosynthesis is largely driven by cyanobacteria, namely Synechococcus and Prochlorococcus. Genes encoding for photosystem (PS) I and II reaction centre proteins are found in cyanophages and are believed to increase their fitness. Two viral PSI gene arrangements are known, psaJF→C→A→B→K→E→D and psaD→C→A→B. The shared genes between these gene cassettes and their encoded proteins are distinguished by %G + C and protein sequence respectively. The data on the psaD→C→A→B gene organization were reported from only two partial gene cassettes coming from Global Ocean Sampling stations in the Pacific and Indian oceans. Now we have extended our search to 370 marine stations from six metagenomic projects. Genes corresponding to both PSI gene arrangements were detected in the Pacific, Indian and Atlantic oceans, confined to a strip along the equator (30°N and 30°S). In addition, we found that the predicted structure of the viral PsaA protein from the psaD→C→A→B organization contains a lumenal loop conserved in PsaA proteins from Synechococcus, but is completely absent in viral PsaA proteins from the psaJF→C→A→B→K→E→D gene organization and most Prochlorococcus strains. This may indicate a co-evolutionary scenario where cyanophages containing either of these gene organizations infect cyanobacterial ecotypes biogeographically restricted to the 30°N and 30°S equatorial strip.


Assuntos
Bacteriófagos/genética , Fotossíntese/genética , Complexo de Proteína do Fotossistema I/genética , Prochlorococcus/genética , Synechococcus/genética , Sequência de Aminoácidos , Organismos Aquáticos/genética , Organismos Aquáticos/metabolismo , Oceano Atlântico , Evolução Biológica , Ordem dos Genes , Genes Virais/genética , Oceano Índico , Metagenômica , Oceano Pacífico , Complexo de Proteína do Fotossistema II/genética , Prochlorococcus/metabolismo , Prochlorococcus/virologia , Synechococcus/metabolismo , Synechococcus/virologia
19.
Ciênc. rural ; 45(8): 1476-1479, 08/2015. graf
Artigo em Inglês | LILACS-Express | ID: lil-753060

RESUMO

Clostridium perfringens type A has been incriminated as the etiologic agent in jejunal hemorrhage syndrome (JHS), which is a disease that affects dairy cattle. Although this microorganism is considered an important enteropathogen the pathogenesis of JHS is still not clear, and there have been no reports of its occurrence in Brazil so far. The aim of this study was to describe the occurrence of JHS by infection with a C. perfringens type A strain carrying the beta-2 toxin gene in a zebu cow in Brazil, for the first time.


Clostridium perfringens tipo A tem sido considerado agente etiológico da síndrome do jejuno hemorrágico (SJH), que é uma doença que afeta comumente os rebanhos de gado. Embora este microrganismo seja considerado um importante enteropatógeno, a patogênese da SJH ainda não foi elucidada, e não havia sido reportada no Brasil até então. O alvo deste estudo foi descrever pela primeira vez a ocorrência da SJH causada por C. perfringens tipo A, carreador do gene da toxina beta-2, em um zebuíno no Brasil.

20.
Virus Res ; 201: 1-7, 2015 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-25701743

RESUMO

Virus-like particles (VLPs) are valuable tools for nanotechnology and nanomedicine. These particles are obtained by the self-assembly, either in vivo or in vitro, of structural proteins of viral capsids. VLPs are excellent scaffolds for surface display of molecules. The N-termini of the structural proteins of human parvovirus B19 (B19V) have been already modified to display peptides or proteins. However, other surface-exposed elements have not been studied as potential locations for peptide display. In this research, we tested the potential of surface loop 62-75 of VP2 protein for the presentation of a 64-residue heterologous peptide. The chimeric protein was able to self-assemble in vitro into VLPs. Improved colloidal stability was observed for these particles, indicating that the peptide is on the surface of the particle. AFM analysis of the chimeric particles shows no obvious difference between the surfaces of particles assembled with VP2 and those assembled with the chimeric VP2. Our results indicate that loop 62-75 is a good candidate for heterologous peptide presentation on the surface of B19V VLPs.


Assuntos
Proteínas do Capsídeo/metabolismo , Técnicas de Visualização da Superfície Celular , Multimerização Proteica , Proteínas Recombinantes de Fusão/metabolismo , Virossomos/metabolismo , Proteínas do Capsídeo/química , Proteínas do Capsídeo/genética , Humanos , Microscopia de Força Atômica , Estabilidade Proteica , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Virossomos/genética
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