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1.
Int J Chron Obstruct Pulmon Dis ; 16: 2203-2215, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34349506

RESUMO

Background: Chronic mucous hypersecretion (CMH or chronic bronchitis) per se or when associated with chronic inflammatory airway diseases such as asthma or chronic obstructive pulmonary disease (COPD) has several adverse clinical consequences. The sputum fluid phase has several candidate proteins including mucins which have the potential of being therapeutic targets, but has not yet been explored in-depth. This study aimed at exploring the profile of sputum proteins in various airway diseases. Methods: Sputum from thirty-one patients with various airway diseases was collected and the fluid phase analyzed by LC-MS/MS and subsequently by sequential window acquisition of all theoretical fragments ion spectra (SWATH) (n = 15) for protein quantitation. Hierarchical clustering and functional grouping were performed. Results: A total of 185 proteins were quantitated by SWATH of which 21 proteins were identified which could distinguish between the clinical phenotypes by hierarchical clustering. Functional protein clustering revealed 4 groups: those that are inflammation related, oxidative stress related, mucin related and a cytoskeletal and calcium related group. The levels of eight proteins (Azurocidin1, Neutrophil defensin 3, Lactotransferrin, Calmodulin 3, Coronin1A, Mucin 5B, Mucin 5AC and BPI fold containing family B1) were significantly altered (relative to mean) in exacerbator prone subjects compared to nonexacerbators. Another simple but useful metric which emerged from this study was total protein concentration in sputum which was significantly higher in frequent exacerbators. Conclusion: Sputum proteins can detect the various airway disease clinical phenotypes. Total protein concentration and eight other proteins are biomarkers for frequent exacerbators. The clinical and therapeutic implications of the functional groups of proteins need further evaluation.


Assuntos
Doença Pulmonar Obstrutiva Crônica , Escarro , Biomarcadores , Cromatografia Líquida , Humanos , Projetos Piloto , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Espectrometria de Massas em Tandem
2.
J Infect Dis ; 224(4): 565-574, 2021 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-34398242

RESUMO

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing coronavirus disease 2019 (COVID-19), has led to significant morbidity and mortality. While most suffer from mild symptoms, some patients progress to severe disease with acute respiratory distress syndrome (ARDS) and associated systemic hyperinflammation. METHODS: First, to characterize key cytokines and their dynamics in this hyperinflammatory condition, we assessed abundance and correlative expression of a panel of 48 cytokines in patients progressing to ARDS as compared to patients with mild disease. Then, in an ongoing randomized controlled trial of convalescent plasma therapy (CPT), we analyzed rapid effects of CPT on the systemic cytokine dynamics as a correlate for the level of hypoxia experienced by the patients. RESULTS: We identified an anti-inflammatory role of CPT independent of its neutralizing antibody content. CONCLUSIONS: Neutralizing antibodies, as well as reductions in circulating interleukin-6 and interferon-γ-inducible protein 10, contributed to marked rapid reductions in hypoxia in response to CPT. CLINICAL TRIAL REGISTRY OF INDIA: CTRI/2020/05/025209. http://www.ctri.nic.in/.


Assuntos
COVID-19/imunologia , COVID-19/terapia , SARS-CoV-2/imunologia , Adulto , Anti-Inflamatórios/uso terapêutico , Anticorpos Neutralizantes/imunologia , COVID-19/tratamento farmacológico , COVID-19/epidemiologia , COVID-19/virologia , Citocinas/sangue , Citocinas/imunologia , Feminino , Humanos , Imunização Passiva/métodos , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Plasma , RNA Viral/isolamento & purificação , Síndrome do Desconforto Respiratório/tratamento farmacológico , Síndrome do Desconforto Respiratório/imunologia , SARS-CoV-2/isolamento & purificação , Carga Viral
3.
J Proteins Proteom ; : 1-7, 2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-33132628

RESUMO

In the last few months, there has been a global catastrophic outbreak of severe acute respiratory syndrome disease caused by the novel coronavirus SARS-CoV-2 affecting millions of people worldwide. Early diagnosis and isolation are key to contain the rapid spread of the virus. Towards this goal, we report a simple, sensitive and rapid method to detect the virus using a targeted mass spectrometric approach, which can directly detect the presence of virus from naso-oropharyngeal swabs. Using a multiple reaction monitoring we can detect the presence of two peptides specific to SARS-CoV-2 in a 2.3 min gradient run with 100% specificity and 90.5% sensitivity when compared to RT-PCR. Importantly, we further show that these peptides could be detected even in the patients who have recovered from the symptoms and have tested negative for the virus by RT-PCR highlighting the sensitivity of the technique. This method has the translational potential of in terms of the rapid diagnostics of symptomatic and asymptomatic COVID-19 and can augment current methods available for diagnosis of SARS-CoV-2.

4.
J Biol Chem ; 295(47): 16037-16057, 2020 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-32934008

RESUMO

Methylenetetrahydrofolate reductase (MTHFR) links the folate cycle to the methionine cycle in one-carbon metabolism. The enzyme is known to be allosterically inhibited by SAM for decades, but the importance of this regulatory control to one-carbon metabolism has never been adequately understood. To shed light on this issue, we exchanged selected amino acid residues in a highly conserved stretch within the regulatory region of yeast MTHFR to create a series of feedback-insensitive, deregulated mutants. These were exploited to investigate the impact of defective allosteric regulation on one-carbon metabolism. We observed a strong growth defect in the presence of methionine. Biochemical and metabolite analysis revealed that both the folate and methionine cycles were affected in these mutants, as was the transsulfuration pathway, leading also to a disruption in redox homeostasis. The major consequences, however, appeared to be in the depletion of nucleotides. 13C isotope labeling and metabolic studies revealed that the deregulated MTHFR cells undergo continuous transmethylation of homocysteine by methyltetrahydrofolate (CH3THF) to form methionine. This reaction also drives SAM formation and further depletes ATP reserves. SAM was then cycled back to methionine, leading to futile cycles of SAM synthesis and recycling and explaining the necessity for MTHFR to be regulated by SAM. The study has yielded valuable new insights into the regulation of one-carbon metabolism, and the mutants appear as powerful new tools to further dissect out the intersection of one-carbon metabolism with various pathways both in yeasts and in humans.


Assuntos
Trifosfato de Adenosina/química , Metilenotetra-Hidrofolato Redutase (NADPH2)/química , S-Adenosilmetionina/química , Proteínas de Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/enzimologia , Trifosfato de Adenosina/genética , Trifosfato de Adenosina/metabolismo , Regulação Alostérica , Humanos , Metilação , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Metilenotetra-Hidrofolato Redutase (NADPH2)/metabolismo , S-Adenosilmetionina/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
5.
J Mol Biol ; 432(20): 5649-5664, 2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32835659

RESUMO

The folding landscape of proteins can change during evolution with the accumulation of mutations that may introduce entropic or enthalpic barriers in the protein folding pathway, making it a possible substrate of molecular chaperones in vivo. Can the nature of such physical barriers of folding dictate the feasibility of chaperone-assistance? To address this, we have simulated the evolutionary step to chaperone-dependence keeping GroEL/ES as the target chaperone and GFP as a model protein in an unbiased screen. We find that the mutation conferring GroEL/ES dependence in vivo and in vitro encode an entropic trap in the folding pathway rescued by the chaperonin. Additionally, GroEL/ES can edit the formation of non-native contacts similar to DnaK/J/E machinery. However, this capability is not utilized by the substrates in vivo. As a consequence, GroEL/ES caters to buffer mutations that predominantly cause entropic traps, despite possessing the capacity to edit both enthalpic and entropic traps in the folding pathway of the substrate protein.


Assuntos
Chaperonina 60/química , Chaperonina 60/metabolismo , Chaperonas Moleculares/química , Chaperonas Moleculares/metabolismo , Dobramento de Proteína , Sítios de Ligação , Chaperonina 60/genética , Chaperoninas , Escherichia coli/metabolismo , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Proteínas de Choque Térmico , Cinética , Chaperonas Moleculares/genética , Mutação
6.
Life Sci Alliance ; 2(4)2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31416893

RESUMO

Nutritional limitation has been vastly studied; however, there is limited knowledge of how cells maintain homeostasis in excess nutrients. In this study, using yeast as a model system, we show that some amino acids are toxic at higher concentrations. With cysteine as a physiologically relevant example, we delineated the pathways/processes that are altered and those that are involved in survival in the presence of elevated levels of this amino acid. Using proteomics and metabolomics approach, we found that cysteine up-regulates proteins involved in amino acid metabolism, alters amino acid levels, and inhibits protein translation-events that are rescued by leucine supplementation. Through a comprehensive genetic screen, we show that leucine-mediated effect depends on a transfer RNA methyltransferase (NCL1), absence of which decouples transcription and translation in the cell, inhibits the conversion of leucine to ketoisocaproate, and leads to tricarboxylic acid cycle block. We therefore propose a role of NCL1 in regulating metabolic homeostasis through translational control.


Assuntos
Metabolômica/métodos , Proteômica/métodos , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , tRNA Metiltransferases/metabolismo , Cisteína/farmacologia , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Biossíntese de Proteínas , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Estresse Fisiológico
7.
J Phys Chem Lett ; 9(20): 6060-6065, 2018 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-30256643

RESUMO

Proteins typically adopt a multitude of flexible and rapidly interconverting conformers, many of which are governed by specific protein interaction domains. Whereas disc-shaped oligomeric HDL and its major protein component ApoA1 have been the focus of several investigations, the structural properties of monomeric ApoA1 remain poorly understood. Using tens of independent molecular simulations (>50 µs), we reveal that ApoA1 adopts a compact conformation. Upon the addition of a physiological concentration of cholesterol to ApoA1, the monomeric protein spontaneously formed a circular conformation. Remarkably, these drastic structural perturbations are driven by a specific cholesterol binding site at the C-terminal and a novel cholesterol binding site at the N-terminal. We propose a mechanism whereby ApoA1 opens in a stagewise manner and mutating the N-terminal binding site destroys the open "belt-shaped" topology. Complementary experiments confirm that the structural changes are induced by specific association of cholesterol with ApoA1, not by the nonspecific hydrophobic effect.


Assuntos
Apolipoproteína A-I/química , Apolipoproteína A-I/metabolismo , Colesterol/metabolismo , Calorimetria , Dicroísmo Circular , Ligação Proteica , Conformação Proteica
8.
Mol Omics ; 14(1): 53-63, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29570205

RESUMO

Perturbations affecting the homoeostasis of endoplasmic reticulum (ER) activate an adaptive signaling known as the unfolded protein response or UPR. Many studies have reported the association between neurological disorders and ER stress. Decreasing ER stress may therefore aid in therapeutic control of neuronal diseases. Sodium 4-phenylbutyrate (4-PBA), a small molecule, has been shown to alleviate ER stress and various neurological diseases, but the mechanistic basis of its action is not well understood. Using an iTRAQ based LC-MS technique we have delineated the effect of 4-PBA on the proteome of human neuroblastoma cells (SK-N-SH) during Tunicamycin-induced ER stress. The proteomic profile of 4-PBA-treated cells revealed that 4-PBA does not alter the cellular proteome to adapt towards ER stress. However, it can alleviate both the toxicity and proteomic alterations, induced by an ER stress inducer. Hence, the therapeutic effect of 4-PBA is primarily due to its ability to resolve ER stress rather than its ability to alter the expression of proteins required for maintaining ER proteostasis. Thus, we posit here that 4-PBA acts as an authentic chemical chaperone by aiding protein folding in the ER.

9.
J Comput Chem ; 38(29): 2528-2537, 2017 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-28856705

RESUMO

Ionization of nucleobases is affected by their biological environment, which includes both the effect of adjacent nucleotides as well as the presence of water around it. Guanine and its nucleotide have the lowest ionization potentials among the various DNA bases. Therefore, the threshold of ionization is dependent on that of guanine and its characterization is crucial to the prediction of interaction of light with DNA. We investigate the effect of solvation on the vertical ionization energies (VIEs) of guanine and its nucleotide. In this work, we have used hybrid quantum mechanics/molecular mechanics (QM/MM) approach with effective fragment potential as the MM method of choice and equation-of-motion coupled-cluster for ionization potential with singles and doubles (EOM-IP-CCSD) as the QM method. The performance of the hybrid scheme with respect to the full QM method shows an accuracy of ≤ 0.02-0.04 eV. The lowest few ionizations of the nucleotide are found to be from different parts of the moiety, that is, the nucleic acid base, phosphate, or sugar, and these ionization energies are very closely spaced giving rise to a very complicated spectrum. Furthermore, microsolvation has large effects on these ionizations and can lead to red or blue shift depending on the position of the water molecule. Even a single water molecule can change the order of ionized states in the nucleotide. The VIEs of the bulk solvated chromophores are predicted and compared to existing experimental spectra. The predominant role of polarization in the solvatochromic shift is noticed. © 2017 Wiley Periodicals, Inc.

10.
Phys Chem Chem Phys ; 18(9): 6526-33, 2016 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-26864778

RESUMO

The accurate estimation of the ionization energies and understanding the nature of the ionized states of the nucleic acid bases (NABs) are crucial to the understanding of the DNA damage mechanism. The vertical ionization energy (VIE) of guanine is the lowest among the NABs and the ionization energies are strongly affected by the environment, such as solvation and characteristics of nearby NABs. Therefore, we investigate the sequence dependence of the VIEs of guanine in B-DNA. We use the equation of motion coupled cluster method for the estimation of ionization potential with single and double excitations (EOM-IP-CCSD) and density functional theory with dispersion corrected ωB97x-D for the estimation of VIEs. A significant amount of non-additivity or cooperativity, directly proportional to charge delocalization, is noticed in the change in VIE due to the interaction with the nearby NABs. While the change in VIE due to base pairing originates predominantly from charge-dipole interactions, stacking between base pairs is a more complicated balance of dispersion and charge-dipole interactions as well as stabilization due to the delocalization of the positive charge. The long range interactions are however dominated by 1/r(3) distance dependence which shows the major role played by charge-dipole interactions. The extent of localization of positive holes on guanine is also estimated for various sequences.


Assuntos
DNA/química , Guanina/química , Dimerização , Íons , Teoria Quântica
11.
Int J Speech Lang Pathol ; 14(6): 520-8, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22924853

RESUMO

Bilingual speakers must learn to modify their speech motor control mechanism based on the linguistic parameters and rules specified by the target language. This study examines if there are aspects of speech motor control which remain invariant regardless of the first (L1) and second (L2) language targets. Based on the age of academic exposure and proficiency in L2, 21 Bengali-English bilingual participants were classified into high (n = 11) and low (n = 10) L2 (English) proficiency groups. Using the Optotrak 3020 motion sensitive camera system, the lips and jaw movements were recorded while participants produced Bengali (L1) and English (L2) sentences. Based on kinematic analyses of the lip and jaw movements, two different variability measures (i.e., lip aperture and lower lip/jaw complex) were computed for English and Bengali sentences. Analyses demonstrated that the two groups of bilingual speakers produced lip aperture complexes (a higher order synergy) that were more consistent in co-ordination than were the lower lip/jaw complexes (a lower order synergy). Similar findings were reported earlier in monolingual English speakers by Smith and Zelaznik. Thus, this hierarchical organization may be viewed as a fundamental principle of speech motor control, since it is maintained even in bilingual speakers.


Assuntos
Arcada Osseodentária/fisiologia , Lábio/fisiologia , Atividade Motora , Movimento , Multilinguismo , Fonética , Acústica da Fala , Qualidade da Voz , Adulto , Fenômenos Biomecânicos , Humanos , Medida da Produção da Fala , Gravação em Vídeo , Adulto Jovem
12.
Percept Mot Skills ; 113(1): 311-30, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21987929

RESUMO

To sound native-like, nonnative speakers need to approximate the articulatory patterns of native speakers. When nonnative speakers deviate from native speakers' production patterns, it gives rise to a nonnative accent. This study examines how proficiency in a second language (L2) is related to processing skills in L2, as measured by the accuracy of consonant production. 10 monolingual speakers of American English, 10 Bengali-English bilinguals with high proficiency in English, and 10 Bengali-English bilinguals with low proficiency in English participated. The participants spoke 16 nonwords of four different syllable lengths. Productions were phonetically transcribed. Results suggested that nonnative speakers' L2 proficiency differentially interacted with overall phonemic accuracy, usage of appropriate place, manner and voicing features, position of consonants within target words, and syllable length. Implications of these findings are discussed in light of customized strategies for modification of nonnative accents.


Assuntos
Multilinguismo , Fonação , Fonética , Acústica da Fala , Testes de Articulação da Fala , Adulto , Humanos , Adulto Jovem
13.
Int J Speech Lang Pathol ; 13(6): 536-48, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21846167

RESUMO

The study explored the influence of second language proficiency on the kinematic duration of single words. Participants produced real and novel words with variable stress targets (e.g., trochaic and iambic) embedded in first language (L1) and second language (L2) sentence frames. Participants were monolingual English speakers (n=10) and Bengali-English bilinguals with early exposure to English (n=10) and late exposure to English (n=10). Bengali was the L1 and English was the L2 for all 20 bilingual participants. Duration of lip movements for the target real and novel words was analysed. Results suggest that kinematic duration of single words was not influenced by speakers' L2 proficiency. However, L2 proficiency influenced foreign accent ratings for the real words, but not the novel words. Kinematic duration and perception of accent were not correlated, which might imply that accent reduction might not always be a direct consequence of shorter word duration.


Assuntos
Lábio/fisiologia , Movimento , Multilinguismo , Fonética , Acústica da Fala , Percepção da Fala , Adulto , Análise de Variância , Fenômenos Biomecânicos , Humanos , Pessoa de Meia-Idade , Medida da Produção da Fala , Fatores de Tempo , Gravação em Vídeo , Adulto Jovem
14.
Microsc Res Tech ; 74(3): 292-300, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20669308

RESUMO

Scanning electron microscopy of different larval stages of the muga silk moth Antheraea assamensis revealed the presence of sensilla chaetica, sensilla trichoidea, sensilla styloconica, gustatory sensilla, sensory pegs, placoid sensilla, etc., on their mouth parts. Some variations were observed in the number and sub-types of sensilla in certain larval stages indicating some differences in sensitivity of the worms in different instars to the food plant and microhabitat.


Assuntos
Larva/anatomia & histologia , Mariposas/anatomia & histologia , Mariposas/embriologia , Boca/anatomia & histologia , Animais , Índia , Microscopia Eletrônica de Varredura , Células Receptoras Sensoriais
15.
Microsc Res Tech ; 74(1): 28-35, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21181707

RESUMO

Scanning electron microcopy of the wing scales from some specific locations in the silk moth, Antheraea assamensis, revealed the presence of 50-60-nm-thick microridges and 80-nm-thick air spaces between them. The principle of optics suggests that when the measured average thickness of microridges or lamellae is about 50-60 nm, that of the air-space between them is about 80-82 nm, then due to the known refractive index of air (1.0) and the infrared refractive index of lamellar cuticle (1.60), the lamellae (microridges) and the intervening lamellar air spaces will have similar optical thickness. A common optical thickness for the two types of layers causes the microridge structures to function in the fashion of a quarter wavelength interference filter and to reflect UV light. Behavioral studies under the natural conditions and short experimental exposure of the moths to artificial UV light suggests that coupling behavior of the moth is governed to a significant extent by these UV-reflecting wing scales. The importance of the study in overcoming a major problem of low autocoupling efficiency of moths in the Muga Silk Industry is discussed with the help of relevant literature.


Assuntos
Mariposas/química , Asas de Animais/química , Animais , Fenômenos Biofísicos , Feminino , Masculino , Microscopia Eletrônica de Varredura , Mariposas/fisiologia , Mariposas/ultraestrutura , Refratometria , Raios Ultravioleta , Asas de Animais/fisiologia , Asas de Animais/ultraestrutura
16.
J Speech Lang Hear Res ; 54(3): 821-35, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21106699

RESUMO

PURPOSE: To assess the influence of second language (L2) proficiency on production characteristics of rhythmic sequences in the L1 (Bengali) and L2 (English), with emphasis on linguistic transfer. One goal was to examine, using kinematic evidence, how L2 proficiency influences the production of iambic and trochaic words, focusing on temporal and spatial aspects of prosody. A second goal was to assess whether prosodic structure influences judgment of foreign accent. METHOD: Twenty Bengali-English bilingual individuals, 10 with low proficiency in English and 10 with high proficiency in English, and 10 monolingual English speakers, participated. Lip and jaw movements were recorded while the bilingual participants produced Bengali and English words embedded in sentences. Lower lip movement amplitude and duration were measured in trochaic and iambic words. Six native English listeners judged the nativeness of the bilingual speakers. RESULTS: Evidence of L1-L2 transfer was observed through duration but not amplitude cues. More proficient L2 speakers varied duration to mark iambic stress. Perceptually, the high-proficiency group received relatively higher native-like accent ratings. Trochees were judged as more native than iambs. CONCLUSIONS: Even in the face of L1-L2 lexical stress transfer, nonnative speakers demonstrated knowledge of prosodic contrasts. Movement duration appears to be more amenable than amplitude to modifications.


Assuntos
Multilinguismo , Fonação/fisiologia , Fonética , Percepção da Fala/fisiologia , Fala/fisiologia , Adulto , Fenômenos Biomecânicos , Feminino , Humanos , Idioma , Masculino , Percepção da Altura Sonora/fisiologia , Adulto Jovem
17.
Microsc Res Tech ; 72(12): 924-32, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19484777

RESUMO

Scanning electron microscopy revealed the presence of a number of cuticular sensillae on the head of different larval stages of the "Muga" silk moth, Antheraea assamensis. These include four types of sensilla trichodea, bead-like folded sensilla, two types of sensilla basiconica, and sensory pegs. The study seems to be the first attempt in describing the morphology and distribution pattern of the cephalic cuticular sensillae of different larval stages of the silk moth Antheraea assamensis, an indigenous species of Northeast India. The possible significance of the sensillae in searching behavior of the larval stages during feeding is discussed with the help of available literature.


Assuntos
Estruturas Animais/ultraestrutura , Cabeça , Mariposas/ultraestrutura , Animais , Índia , Larva/ultraestrutura , Microscopia Eletrônica de Varredura
18.
Microsc Res Tech ; 72(2): 76-8, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18937248

RESUMO

Environmental stress due to acidic pH of water was found to be one of the major factors leading to toxic effects on the sperm of a hill-stream fish Devario aequipinnatus of Meghalaya, India. The Scanning Electron Microscopy of the transverse section of testes of the fish collected from its natural habitat with acidic pH (5.6-6.0) showed that the sperms were clumped together and their tails were either absent or were of extremely small length. The acrosome and midpiece were also not well differentiated. When the fingerlings from the natural habitat were reared to maturity in aquarium with water from natural habitat after changing the pH to alkaline range (8.0-8.2), the clumping of the sperm was not observed. The sperm tail was found to be well-developed along with well-differentiated acrosome and midpiece. Since the only change in the water quality parameters of the experimental aquarium as compared to those of the natural habitat was the pH, it is evident that the abnormal features of the sperm observed in fish from natural habitat is mainly because of environmental acid stress.


Assuntos
Cyprinidae/fisiologia , Microscopia Eletrônica de Varredura , Espermatozoides/ultraestrutura , Estresse Fisiológico , Animais , Cyprinidae/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Masculino , Rios , Cabeça do Espermatozoide/ultraestrutura , Motilidade Espermática , Espermatozoides/fisiologia , Testículo/ultraestrutura , Poluição Química da Água
19.
Microsc Res Tech ; 72(4): 333-7, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19067358

RESUMO

Epizootic ulcerative syndrome (EUS)-affected Puntius ticto exhibited a number of abnormalities in scale, gill, skin, and muscle at surface microstructural level. Lepidontal damage including breakage of individual lepidonts and complete loss of lepidontal assembly was evident in the scale. Disturbances in the gill included fusion of gill-lamella, distortion of lamellar surface, damage of primary and secondary gill lamella as well as breakage of gill racker. The skin of EUS-affected Puntius ticto showed breakage of epidermal cell boundary, distortion, and loss of alignment of cells including lesions at places. Loss of alignment of muscles along with breakage and distortion of individual fibers was also evident. The similarities of these abnormalities in EUS-affected Puntius ticto with those of pesticide and other pollutant toxicity reported in some fish is discussed with the help of relevant literature.


Assuntos
Cyprinidae/anatomia & histologia , Doenças dos Peixes/patologia , Brânquias/patologia , Pele/patologia , Úlcera/veterinária , Animais , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/etiologia , Índia/epidemiologia , Microscopia Eletrônica de Varredura , Praguicidas/toxicidade , Síndrome , Úlcera/epidemiologia , Úlcera/etiologia , Úlcera/patologia , Poluentes Químicos da Água/toxicidade
20.
J Speech Lang Hear Res ; 51(2): 321-32, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18367680

RESUMO

PURPOSE: To examine how age of immersion and proficiency in a 2nd language influence speech movement variability and speaking rate in both a 1st language and a 2nd language. METHOD: A group of 21 Bengali-English bilingual speakers participated. Lip and jaw movements were recorded. For all 21 speakers, lip movement variability was assessed based on productions of Bengali (L1; 1st language) and English (L2; 2nd language) sentences. For analyses related to the influence of L2 proficiency on speech production processes, participants were sorted into low- (n = 7) and high-proficiency (n = 7) groups. Lip movement variability and speech rate were evaluated for both of these groups across L1 and L2 sentences. RESULTS: Surprisingly, adult bilingual speakers produced equally consistent speech movement patterns in their production of L1 and L2. When groups were sorted according to proficiency, highly proficient speakers were marginally more variable in their L1. In addition, there were some phoneme-specific effects, most markedly that segments not shared by both languages were treated differently in production. Consistent with previous studies, movement durations were longer for less proficient speakers in both L1 and L2. INTERPRETATION: In contrast to those of child learners, the speech motor systems of adult L2 speakers show a high degree of consistency. Such lack of variability presumably contributes to protracted difficulties with acquiring nativelike pronunciation in L2. The proficiency results suggest bidirectional interactions across L1 and L2, which is consistent with hypotheses regarding interference and the sharing of phonological space. A slower speech rate in less proficient speakers implies that there are increased task demands on speech production processes.


Assuntos
Arcada Osseodentária/fisiologia , Lábio/fisiologia , Movimento/fisiologia , Multilinguismo , Fala/fisiologia , Adulto , Fenômenos Biomecânicos , Humanos , Aprendizagem , Fonética , Medida da Produção da Fala , Fatores de Tempo
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