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1.
Sci Rep ; 14(1): 10699, 2024 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-38729974

RESUMEN

In recent years it became apparent that, in mammals, rhodopsin and other opsins, known to act as photosensors in the visual system, are also present in spermatozoa, where they function as highly sensitive thermosensors for thermotaxis. The intriguing question how a well-conserved protein functions as a photosensor in one type of cells and as a thermosensor in another type of cells is unresolved. Since the moiety that confers photosensitivity on opsins is the chromophore retinal, we examined whether retinal is substituted in spermatozoa with a thermosensitive molecule. We found by both functional assays and mass spectrometry that retinal is present in spermatozoa and required for thermotaxis. Thus, starvation of mice for vitamin A (a precursor of retinal) resulted in loss of sperm thermotaxis, without affecting motility and the physiological state of the spermatozoa. Thermotaxis was restored after replenishment of vitamin A. Using reversed-phase ultra-performance liquid chromatography mass spectrometry, we detected the presence of retinal in extracts of mouse and human spermatozoa. By employing UltraPerformance convergence chromatography, we identified a unique retinal isomer in the sperm extracts-tri-cis retinal, different from the photosensitive 11-cis isomer in the visual system. The facts (a) that opsins are thermosensors for sperm thermotaxis, (b) that retinal is essential for thermotaxis, and (c) that tri-cis retinal isomer uniquely resides in spermatozoa and is relatively thermally unstable, suggest that tri-cis retinal is involved in the thermosensing activity of spermatozoa.


Asunto(s)
Opsinas , Retinaldehído , Espermatozoides , Vitamina A , Masculino , Animales , Espermatozoides/metabolismo , Espermatozoides/fisiología , Ratones , Opsinas/metabolismo , Humanos , Retinaldehído/metabolismo , Vitamina A/metabolismo , Taxia/fisiología , Motilidad Espermática/fisiología , Isomerismo
2.
Chem Sci ; 14(36): 9951-9958, 2023 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-37736621

RESUMEN

The function of microbial as well as mammalian retinal proteins (aka rhodopsins) is associated with a photocycle initiated by light excitation of the retinal chromophore of the protein, covalently bound through a protonated Schiff base linkage. Although electrostatics controls chemical reactions of many organic molecules, attempt to understand its role in controlling excited state reactivity of rhodopsins and, thereby, their photocycle is scarce. Here, we investigate the effect of highly conserved tryptophan residues, between which the all-trans retinal chromophore of the protein is sandwiched in microbial rhodopsins, on the charge distribution along the retinal excited state, quantum yield and nature of the light-induced photocycle and absorption properties of Gloeobacter rhodopsin (GR). Replacement of these tryptophan residues by non-aromatic leucine (W222L and W122L) or phenylalanine (W222F) does not significantly affect the absorption maximum of the protein, while all the mutants showed higher sensitivity to photobleaching, compared to wild-type GR. Flash photolysis studies revealed lower quantum yield of trans-cis photoisomerization in W222L as well as W222F mutants relative to wild-type. The photocycle kinetics are also controlled by these tryptophan residues, resulting in altered accumulation and lifetime of the intermediates in the W222L and W222F mutants. We propose that protein-retinal interactions facilitated by conserved tryptophan residues are crucial for achieving high quantum yield of the light-induced retinal isomerization, and affect the thermal retinal re-isomerization to the resting state.

3.
Arch Microbiol ; 205(8): 274, 2023 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-37401995

RESUMEN

Highly hydrophobic compounds like petroleum and their byproducts, once released into the environment, can persist indefinitely by virtue of their ability to resist microbial degradation, ultimately paving the path to severe environmental pollution. Likewise, the accumulation of toxic heavy metals like lead, cadmium, chromium, etc., in the surroundings poses an alarming threat to various living organisms. To remediate the matter in question, the applicability of a biosurfactant produced from the mangrove bacterium Bacillus pumilus NITDID1 (Accession No. KY678446.1) is reported here. The structural characterization of the produced biosurfactant revealed it to be a lipopeptide and has been identified as pumilacidin through FTIR, NMR, and MALDI-TOF MS. The critical micelle concentration of pumilacidin was 120 mg/L, and it showed a wide range of stability in surface tension reduction experiments under various environmental conditions and exhibited a high emulsification index of as much as 90%. In a simulated setup of engine oil-contaminated sand, considerable oil recovery (39.78%) by this biosurfactant was observed, and upon being added to a microbial consortium, there was an appreciable enhancement in the degradation of the used engine oil. As far as the heavy metal removal potential of biosurfactant is concerned, as much as 100% and 82% removal was observed for lead and cadmium, respectively. Thus, in a nutshell, the pumilacidin produced from Bacillus pumilus NITDID1 holds promise for multifaceted applications in the field of environmental remediation.


Asunto(s)
Bacillus pumilus , Contaminantes Ambientales , Petróleo , Biodegradación Ambiental , Lipopéptidos/química , Bacillus pumilus/genética , Bacillus pumilus/metabolismo , Cadmio , Tensoactivos/química , Petróleo/metabolismo
4.
Nature ; 615(7952): 535-540, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36859551

RESUMEN

Energy transfer from light-harvesting ketocarotenoids to the light-driven proton pump xanthorhodopsins has been previously demonstrated in two unique cases: an extreme halophilic bacterium1 and a terrestrial cyanobacterium2. Attempts to find carotenoids that bind and transfer energy to abundant rhodopsin proton pumps3 from marine photoheterotrophs have thus far failed4-6. Here we detected light energy transfer from the widespread hydroxylated carotenoids zeaxanthin and lutein to the retinal moiety of xanthorhodopsins and proteorhodopsins using functional metagenomics combined with chromophore extraction from the environment. The light-harvesting carotenoids transfer up to 42% of the harvested energy in the violet- or blue-light range to the green-light absorbing retinal chromophore. Our data suggest that these antennas may have a substantial effect on rhodopsin phototrophy in the world's lakes, seas and oceans. However, the functional implications of our findings are yet to be discovered.


Asunto(s)
Organismos Acuáticos , Procesos Fototróficos , Bombas de Protones , Rodopsinas Microbianas , Organismos Acuáticos/metabolismo , Organismos Acuáticos/efectos de la radiación , Bacterias/metabolismo , Bacterias/efectos de la radiación , Carotenoides/metabolismo , Color , Cianobacterias/metabolismo , Cianobacterias/efectos de la radiación , Procesos Heterotróficos/efectos de la radiación , Luz , Océanos y Mares , Procesos Fototróficos/efectos de la radiación , Bombas de Protones/metabolismo , Bombas de Protones/efectos de la radiación , Rodopsinas Microbianas/metabolismo , Rodopsinas Microbianas/efectos de la radiación , Zeaxantinas/metabolismo , Zeaxantinas/efectos de la radiación , Luteína/metabolismo , Luteína/efectos de la radiación , Metagenoma , Lagos
5.
J Phys Chem B ; 126(43): 8680-8688, 2022 11 03.
Artículo en Inglés | MEDLINE | ID: mdl-36281583

RESUMEN

Photoreceptor proteins play a critical role in light utilization for energy conversion and environmental sensing. Rhodopsin is a prototypical photoreceptor protein containing a retinal group that functions as a light-receptive site. It is essential to characterize the structure of the retinal chromophore because the chromophore structure, along with retinal-protein interactions, regulates which wavelengths of light are absorbed. Resonance Raman spectroscopy is a powerful tool to characterize chromophore structures in proteins. The resonance Raman spectra of heliorhodopsins, a recently discovered rhodopsin family, were previously reported to exhibit two intense ethylenic C═C stretching bands never observed for type-1 rhodopsins. Here, we show that the double-band feature in the ethylenic C═C stretching modes is not due to structural inhomogeneity but rather to the retinal polyene chain's linear structure. It contrasts with bent all-trans chromophore in type-1 rhodopsins. The linear structure of the chromophore results from weak atomic contacts between the 13-methyl group and a nearby Trp side chain, which can slow thermal reisomerization in the photocycle. It is possible that the deceleration of reisomerization increases the lifetime of the signaling intermediate for photosensory function.


Asunto(s)
Rodopsina , Rodopsinas Microbianas , Rodopsina/química , Rodopsinas Microbianas/química , Espectrometría Raman/métodos , Vibración
6.
J Phys Chem Lett ; 13(34): 8134-8140, 2022 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-36000820

RESUMEN

The decades-long ultrafast examination of nearly a dozen microbial retinal proteins, ion pumps, and sensory photoreceptors has not identified structure-function indicators which predict photoisomerization dynamics, whether it will be sub-picosecond and ballistic or drawn out with complex curve-crossing kinetics. Herein, we report the emergence of such an indicator. Using pH control over retinal isomer ratios, photoinduced transient absorption is recorded in an inward proton pumping Antarctic microbial rhodopsin (AntR) for 13-cis and all-trans retinal resting states. The all-trans fluorescent state decays with 1 ps exponential kinetics. In contrast, in 13-cis it decays within ∼300 fs accompanied by continuous spectral evolution, indicating ballistic internal conversion. The coherent wave packet nature of 13-cis isomerization in AntR matches published results for bacteriorhodopsin (BR) and Anabaena sensory rhodopsin (ASR), which also accommodate both all-trans and 13-cis retinal resting states, marking the emergence of a first structure-photodynamics indicator which holds for all three tested pigments.


Asunto(s)
Anabaena , Bacteriorodopsinas , Rodopsinas Sensoriales , Regiones Antárticas , Isomerismo , Rodopsinas Microbianas/metabolismo
7.
Nat Struct Mol Biol ; 29(6): 592-603, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35710843

RESUMEN

Many organisms sense light using rhodopsins, photoreceptive proteins containing a retinal chromophore. Here we report the discovery, structure and biophysical characterization of bestrhodopsins, a microbial rhodopsin subfamily from marine unicellular algae, in which one rhodopsin domain of eight transmembrane helices or, more often, two such domains in tandem, are C-terminally fused to a bestrophin channel. Cryo-EM analysis of a rhodopsin-rhodopsin-bestrophin fusion revealed that it forms a pentameric megacomplex (~700 kDa) with five rhodopsin pseudodimers surrounding the channel in the center. Bestrhodopsins are metastable and undergo photoconversion between red- and green-absorbing or green- and UVA-absorbing forms in the different variants. The retinal chromophore, in a unique binding pocket, photoisomerizes from all-trans to 11-cis form. Heterologously expressed bestrhodopsin behaves as a light-modulated anion channel.


Asunto(s)
Canales Iónicos , Rodopsina , Bestrofinas , Rodopsina/química
8.
Biotechnol Bioeng ; 119(7): 1997-2003, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35324016

RESUMEN

Immunoglobulin M (IgM) antibodies hold promise as anticancer drugs and as agents for promoting immune homeostasis. This promise has not been realized due to low expression levels in mammalian cells producing IgM class antibodies, and the failure of protein A chromatography for IgM purification. Here, we describe a nonchromatographic platform for quantitatively capturing IgMs at neutral pH, which is then recovered with 86%-94% yield and >95% purity at pH 3. The platform contains micelles conjugated with the [(bathophenanthroline)3 :Fe2+ ] amphiphilic complex. Inclusion of amino acid monomers, for example, phenylalanine or tyrosine, during conjugation of detergent micelles, allows subsequent extraction of IgMs at close to neutral pH. With the successful implementation of this purification platform for both polyclonal humans and bovine IgMs, we anticipate similar results for monoclonal IgMs, most relevant for the pharmaceutical industry.


Asunto(s)
Detergentes , Micelas , Animales , Anticuerpos Monoclonales/metabolismo , Bovinos , Humanos , Inmunoglobulina M/metabolismo , Mamíferos/metabolismo , Proteína Estafilocócica A
9.
J Phys Chem B ; 125(31): 8797-8804, 2021 08 12.
Artículo en Inglés | MEDLINE | ID: mdl-34342994

RESUMEN

Heliorhodopsins are a recently discovered diverse retinal protein family with an inverted topology of the opsin where the retinal protonated Schiff base proton is facing the cell cytoplasmic side in contrast to type 1 rhodopsins. To explore whether light-induced retinal double-bond isomerization is a prerequisite for triggering protein conformational alterations, we utilized the retinal oxime formation reaction and thermal denaturation of a native heliorhodopsin of Thermoplasmatales archaeon SG8-52-1 (TaHeR) as well as a trans-locked retinal analogue (TaHeRL) in which the critical C13═C14 double-bond isomerization is prevented. We found that both reactions are light-accelerated not only in the native but also in the "locked" pigment despite lacking any isomerization. It is suggested that light-induced charge redistribution in the retinal excited state polarizes the protein and triggers protein conformational perturbations that thermally decay in microseconds. The extracted activation energy and the frequency factor for both the reactions reveal that the light enhancement of TaHeR differs distinctly from the earlier studied type 1 microbial rhodopsins.


Asunto(s)
Rodopsina , Rodopsinas Microbianas , Luz , Conformación Proteica , Retina , Retinaldehído , Bases de Schiff
10.
J Photochem Photobiol B ; 221: 112241, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34130090

RESUMEN

Rhodopsin and carotenoids are two molecules that certain bacteria use to absorb and utilize light. Type I rhodopsin, the simplest active proton transporter, converts light energy into an electrochemical potential. Light produces a proton gradient, which is known as the proton motive force across the cell membrane. Some carotenoids are involved in light absorbance and transfer of absorbed energy to chlorophyll during photosynthesis. A previous study in Salinibacter ruber has shown that carotenoids act as antennae to harvest light and transfer energy to retinal in xanthorhodopsin (XR). Here, we describe the role of canthaxanthin (CAN), a carotenoid, as an antenna for Gloeobacter rhodopsin (GR). The non-covalent complex formed by the interaction between CAN and GR doubled the proton pumping speed and improved the pumping capacity by 1.5-fold. The complex also tripled the proton pumping speed and improved the pumping capacity by 5-fold in the presence of strong and weak light, respectively. Interestingly, when canthaxanthin was bound to Gloeobacter rhodopsin, it showed a 126-fold increase in heat resistance, and it survived better under drought conditions than Gloeobacter rhodopsin. The results suggest direct complementation of Gloeobacter rhodopsin with a carotenoid for primitive solar energy harvesting in cyanobacteria.


Asunto(s)
Cantaxantina/química , Rodopsinas Microbianas/química , Energía Solar , Secuencia de Aminoácidos , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Bacteroidetes/metabolismo , Sitios de Unión , Calorimetría , Cantaxantina/metabolismo , Cianobacterias/metabolismo , Luz , Unión Proteica , Rodopsinas Microbianas/metabolismo , Alineación de Secuencia
11.
Sci Rep ; 11(1): 11697, 2021 06 03.
Artículo en Inglés | MEDLINE | ID: mdl-34083598

RESUMEN

The research described in this report seeks to present proof-of-concept for a novel and robust platform for purification of antibody fragments and to define and optimize the controlling parameters. Purification of antigen-binding F(ab')2 fragments is achieved in the absence of chromatographic media or specific ligands, rather by using clusters of non-ionic detergent (e.g. Tween-60, Brij-O20) micelles chelated via Fe2+ ions and the hydrophobic chelator, bathophenanthroline (batho). These aggregates, quantitatively capture the F(ab')2 fragment in the absence or presence of E. coli lysate and allow extraction of only the F(ab')2 domain at pH 3.8 without concomitant aggregate dissolution or coextraction of bacterial impurities. Process yields range from 70 to 87% by densitometry. Recovered F(ab')2 fragments are monomeric (by dynamic light scattering), preserve their secondary structure (by circular dichroism) and are as pure as those obtained via Protein A chromatography (from a mixture of F(ab')2 and Fc fragments). The effect of process parameters on Ab binding and Ab extraction (e.g. temperature, pH, ionic strength, incubation time, composition of extraction buffer) are reported, using a monoclonal antibody (mAb) and polyclonal human IgG's as test samples.


Asunto(s)
Fragmentos Fab de Inmunoglobulinas/química , Fragmentos de Inmunoglobulinas/metabolismo , Proteína Estafilocócica A/química , Anticuerpos Monoclonales/química , Cromatografía de Afinidad , Escherichia coli/metabolismo , Fragmentos Fc de Inmunoglobulinas/química , Inmunoglobulina G/química , Micelas
12.
Mol Autism ; 10: 11, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30911366

RESUMEN

Autism (MIM 209850) is a multifactorial disorder with a broad clinical presentation. A number of high-confidence ASD risk genes are known; however, the contribution of non-genetic environmental factors towards ASD remains largely uncertain. Here, we present a bioinformatics resource of genetic and induced models of ASD developed using a shared annotation platform. Using this data, we depict the intricate trends in the research approaches to analyze rodent models of ASD. We identify the top 30 most frequently studied phenotypes extracted from rodent models of ASD based on 787 publications. As expected, many of these include animal model equivalents of the "core" phenotypes associated with ASD, such as impairments in social behavior and repetitive behavior, as well as several comorbid features of ASD including anxiety, seizures, and motor-control deficits. These phenotypes have also been studied in models based on a broad range of environmental inducers present in the database, of which gestational exposure to valproic acid (VPA) and maternal immune activation models comprising lipopolysaccharide (LPS) and poly I:C are the most studied. In our unique dataset of rescue models, we identify 24 pharmaceutical agents tested on established models derived from various ASD genes and CNV loci for their efficacy in mitigating symptoms relevant for ASD. As a case study, we analyze a large collection of Shank3 mouse models providing a high-resolution view of the in vivo role of this high-confidence ASD gene, which is the gateway towards understanding and dissecting the heterogeneous phenotypes seen in single-gene models of ASD. The trends described in this study could be useful for researchers to compare ASD models and to establish a complete profile for all relevant animal models in ASD research.


Asunto(s)
Trastorno Autístico/genética , Modelos Animales de Enfermedad , Fenotipo , Animales , Trastorno Autístico/tratamiento farmacológico , Trastorno Autístico/patología , Bases de Datos Genéticas , Ratones , Ratas , Investigación Biomédica Traslacional/normas
13.
Nucleic Acids Res ; 46(D1): D1049-D1054, 2018 01 04.
Artículo en Inglés | MEDLINE | ID: mdl-29186576

RESUMEN

AutDB is a deeply annotated resource for exploring the impact of genetic variations associated with autism spectrum disorders (ASD). First released in 2007, AutDB has evolved into a multi-modular resource of diverse types of genetic and functional evidence related to ASD. Current modules include: Human Gene, which annotates all ASD-linked genes and their variants; Animal Model, which catalogs behavioral, anatomical and physiological data from rodent models of ASD; Protein Interaction (PIN), which builds interactomes from direct relationships of protein products of ASD genes; and Copy Number Variant (CNV), which catalogs deletions and duplications of chromosomal loci identified in ASD. A multilevel data-integration strategy is utilized to connect the ASD genes to the components of the other modules. All information in this resource is manually curated by expert scientists from primary scientific publications and is referenced to source articles. AutDB is actively maintained with a rigorous quarterly data release schedule. As of June 2017, AutDB contains detailed annotations for 910 genes, 2197 CNV loci, 1060 rodent models and 38 296 PINs. With its widespread use by the research community, AutDB serves as a reference resource for analysis of large datasets, accelerating ASD research and potentially leading to targeted drug treatments. AutDB is available at http://autism.mindspec.org/autdb/Welcome.do.


Asunto(s)
Trastorno del Espectro Autista/genética , Bases de Datos Genéticas , Variación Genética , Animales , Trastorno del Espectro Autista/fisiopatología , Conducta Animal , Variaciones en el Número de Copia de ADN , Humanos , Ratones , Mapeo de Interacción de Proteínas , Ratas
14.
ACS Omega ; 2(9): 5504-5517, 2017 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-30023748

RESUMEN

Herein, we report a comprehensive study on the interaction of three protomeric forms of the antibacterial drug norfloxacin (nfx) with the enzymatic protein human lysozyme (lyz). Norfloxacin, having the option for two-stage acid-base equilibria, converts from cationic (nfx+) to zwitterionic (nfx±) form, followed by an anionic (nfx-) species, with increasing pH. Among these protomeric forms, lysozyme binds nfx± most robustly, whereas nfx- has a weak association and nfx+ does not show any interaction. In lysozyme, the location of the drug was ascertained by competitive binding assay with 8-anilino-1-naphthalenesulfonate, and this was further examined with molecular docking simulation. The binding process was found to be primarily governed by hydrogen bonding and van der Waals interactions. The study has further revealed that preferential binding of nfx± by the protein over nfx- led to a switchover of nfx- to nfx±; and the resulting increased population of nfx± over the other is beneficial for the pharmacological activity of the drug in terms of its accumulation in the target bacterial cells. The present study accomplishes two important objectives. It holds significance regarding the differential interaction of multiprotomeric drugs with biomolecules, such as proteins, enzymes, lipid membranes, etc., and also on such biomolecule-assisted alteration of the acid-base equilibrium and consequent bioavailability of the drug. The findings are useful from the viewpoints of dispensation, distribution, and metabolism of any prototropic drug in living systems as they encounter several biomolecules in vivo. Another importance of this work stems from the study of comparative binding responses of lysozyme toward a drug existing in multiple forms depending on its protonation states or some other chemical processes.

15.
J Phys Chem B ; 120(29): 7076-87, 2016 07 28.
Artículo en Inglés | MEDLINE | ID: mdl-27355857

RESUMEN

Here we report on the excited-state behavior in terms of the excited-state proton-transfer (ESPT) reaction as well as the ground-state acid-base property of pyranine [8-hydroxypyrene-1,3,6-trisulfonate (HPTS)] in the presence of an enzymatic protein, human lysozyme (LYZ). HPTS forms a 1:1 ground-state complex with LYZ having the binding constant KBH = (1.4 ± 0.05) × 10(4) M(-1), and its acid-base equilibrium gets shifted toward the deprotonated conjugate base (RO(-)), resulting in a downward shift in pKa. This suggests that the conjugate base (RO(-)) is thermodynamically more favored over the protonated (ROH) species inside the lysozyme matrix, resulting in an increased population of the deprotonated form. However, for the release of the proton from the excited photoacid, interestingly, the rate of proton transfer gets slowed down due to the "slow" acceptor biological water molecules present in the immediate vicinity of the fluorophore binding region inside the protein. The observed ESPT time constants, ∼140 and ∼750 ps, of protein-bound pyranine are slower than in bulk aqueous media (∼100 ps, single exponential). The molecular docking study predicts that the most probable binding location of the fluorophore is in a region near to the active site of the protein. Here we also report on the effect of external electrolyte (NaCl) on the reverse modulation of ground-state prototropy as well as the ESPT process of the protein-bound pyranine. It is found that there is a dominant role of electrostatic forces in the HPTS-LYZ interaction process, because an increase in ionic strength by the addition of NaCl dislodges the fluorophore from the protein pocket to the bulk again. The study shows a considerably different perspective of the perturbation offered by the model macromolecular host used, unlike the available literature reports on the concerned photoacid.

16.
J Toxicol ; 2015: 504360, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26839546

RESUMEN

Ambur, a town located on the banks of Palar River, is considered one of the most polluted areas in India and occupied by hundreds of tanneries and leather product units. The present study was designed to evaluate the toxic effect of discharged tannery effluent (TE) on model agricultural crops, ecofriendly microorganisms, and human blood cells. The phytotoxic effects of TE tested on Allium cepa and Lemna minor revealed inhibition of root growth and significant reduction in number of fronds, protein, and chlorophyll content. Moreover, TE induced chlorosis and tissue necrosis in Nostoc muscorum at low concentration (10%). TE has also negative impact on ecofriendly microorganisms, Bacillus thuringiensis, Rhizobium etli, and Aspergillus terreus which play an important role in the nutrition of plant growth. The genotoxicity of TE was investigated in human leukocytes which showed interference with normal mitotic division with subsequent cell lysis. It also intervened with the normal replication process and induced micronucleus formation in the healthy leukocyte. 5% concentration of TE has been revealed to be toxic to erythrocytes. From this study TE found in the Palar River of Ambur has adverse effects on all the three levels of organisms in ecosystem even at lower concentrations.

17.
3 Biotech ; 5(2): 153-164, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28324576

RESUMEN

The present study was focused on isolation, screening, characterization and application of biosurfactant producing marine actinobacteria. Twenty actinobacteria were isolated from marine water sample and were primarily screened for biosurfactant production using hemolytic activity method. Among the 20 isolates, six showed positive result for hemolytic activity and those were taken for further secondary screening tests such as oil collapse method, oil spreading method and emulsification method. From the results of secondary screening analysis, two isolates (SIS-3 and SIS-20) were selected and further used to carry out biosurfactant characterization test such as pH, density, surface tension and viscosity determination. Comparing biosurfactant characterization results, SIS-3 was chosen for further analysis and application. FT-IR and GC-MS were carried out for analysis of biosurfactant from isolate SIS-3 and the compound detected was rhamnolipid. The isolate (SIS-3) was identified as Nocardiopsis using 16S rRNA gene sequencing and named as 'Nocardiopsis VITSISB' (KC958579) which was further applied for immobilizing whole cells for engine oil degradation by constructing an aquatic model and using natural products such as soybean meal, sugarcane juice as nutrient source. The oil was efficiently degraded by rhamnolipid producing Nocardiopsis VITSISB (KC958579) within 25 days which indicated that the strain can act as a natural candidate for the bioremediation of oil spill in ocean.

18.
Sci Transl Med ; 5(201): 201ra120, 2013 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-24005160

RESUMEN

Down syndrome (DS) is among the most frequent genetic causes of intellectual disability, and ameliorating this deficit is a major goal in support of people with trisomy 21. The Ts65Dn mouse recapitulates some major brain structural and behavioral phenotypes of DS, including reduced size and cellularity of the cerebellum and learning deficits associated with the hippocampus. We show that a single treatment of newborn mice with the Sonic hedgehog pathway agonist SAG 1.1 (SAG) results in normal cerebellar morphology in adults. Further, SAG treatment at birth rescued phenotypes associated with hippocampal deficits that occur in untreated adult Ts65Dn mice. This treatment resulted in behavioral improvements and normalized performance in the Morris water maze task for learning and memory. SAG treatment also produced physiological effects and partially rescued both N-methyl-d-aspartate (NMDA) receptor-dependent synaptic plasticity and NMDA/AMPA receptor ratio, physiological measures associated with memory. These outcomes confirm an important role for the hedgehog pathway in cerebellar development and raise the possibility for its direct influence in hippocampal function. The positive results from this approach suggest a possible direction for therapeutic intervention to improve cognitive function for this population.


Asunto(s)
Ciclohexilaminas/química , Síndrome de Down/tratamiento farmacológico , Proteínas Hedgehog/agonistas , Proteínas Hedgehog/metabolismo , Tiofenos/química , Animales , Conducta Animal , Cerebelo/metabolismo , Trastornos del Conocimiento/tratamiento farmacológico , Modelos Animales de Enfermedad , Electrofisiología/métodos , Hipocampo/metabolismo , Depresión Sináptica a Largo Plazo , Masculino , Aprendizaje por Laberinto , Memoria/efectos de los fármacos , Ratones , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Plasticidad Neuronal , Fenotipo , Células de Purkinje/citología , Receptores AMPA/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Transmisión Sináptica
19.
Hum Mol Genet ; 22(24): 4901-13, 2013 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-23863462

RESUMEN

SNM1B/Apollo is a DNA nuclease that has important functions in telomere maintenance and repair of DNA interstrand crosslinks (ICLs) within the Fanconi anemia (FA) pathway. SNM1B is required for efficient localization of key repair proteins, such as the FA protein, FANCD2, to sites of ICL damage and functions epistatically to FANCD2 in cellular survival to ICLs and homology-directed repair. The FA pathway is also activated in response to replication fork stalling. Here, we sought to determine the importance of SNM1B in cellular responses to stalled forks in the absence of a blocking lesion, such as ICLs. We found that depletion of SNM1B results in hypersensitivity to aphidicolin, a DNA polymerase inhibitor that causes replication stress. We observed that the SNM1B nuclease is required for efficient localization of the DNA repair proteins, FANCD2 and BRCA1, to subnuclear foci upon aphidicolin treatment, thereby indicating SNM1B facilitates direct repair of stalled forks. Consistent with a role for SNM1B subsequent to recognition of the lesion, we found that SNM1B is dispensable for upstream events, including activation of ATR-dependent signaling and localization of RPA, γH2AX and the MRE11/RAD50/NBS1 complex to aphidicolin-induced foci. We determined that a major consequence of SNM1B depletion is a marked increase in spontaneous and aphidicolin-induced chromosomal gaps and breaks, including breakage at common fragile sites. Thus, this study provides evidence that SNM1B functions in resolving replication stress and preventing accumulation of genomic damage.


Asunto(s)
Sitios Frágiles del Cromosoma , Enzimas Reparadoras del ADN/metabolismo , Replicación del ADN , Inestabilidad Genómica , Proteínas Nucleares/metabolismo , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Afidicolina/farmacología , Proteína BRCA1/metabolismo , Línea Celular , Núcleo Celular/metabolismo , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/genética , Cromatina/metabolismo , Daño del ADN , Reparación del ADN , Enzimas Reparadoras del ADN/química , Enzimas Reparadoras del ADN/genética , Exodesoxirribonucleasas , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/metabolismo , Expresión Génica , Histonas/metabolismo , Humanos , Complejos Multiproteicos/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/genética , Unión Proteica , Dominios y Motivos de Interacción de Proteínas , Transporte de Proteínas , Proteína de Replicación A/metabolismo , Transducción de Señal/efectos de los fármacos , Ubiquitinación
20.
Obstet Med ; 6(2): 72-75, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27757160

RESUMEN

BACKGROUND: In the last maternal death enquiries report there were 14 indirect deaths due to epilepsy. METHODS: Retrospective case-note analysis of epileptic women seen antenatally over two separate time periods were examined. Care in the routine antenatal clinic (ANC) was compared with that in the obstetric medicine clinic (OMC). RESULTS: 1st audit, 65 epileptic women seen. In OMC 14% had documented preconception counselling, 58% were on anti-epileptic drugs (AEDs). In ANC 0% had documented preconception counselling, 34% were on AEDs. 2nd audit, 88 epileptic women seen. In OMC 37.5% of women had preconception counselling, 84% were on AEDs. In ANC, 4.2% had preconception counselling, 31% were on AEDs. CONCLUSIONS: Women seen in OMC received care more compliant with Scottish Obstetric Group and Audit Project recommendations. All women with epilepsy should be reviewed in an OMC.

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