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1.
Phys Rev Lett ; 130(12): 122502, 2023 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-37027859

RESUMEN

The excited states of N=44 ^{74}Zn were investigated via γ-ray spectroscopy following ^{74}Cu ß decay. By exploiting γ-γ angular correlation analysis, the 2_{2}^{+}, 3_{1}^{+}, 0_{2}^{+}, and 2_{3}^{+} states in ^{74}Zn were firmly established. The γ-ray branching and E2/M1 mixing ratios for transitions deexciting the 2_{2}^{+}, 3_{1}^{+}, and 2_{3}^{+} states were measured, allowing for the extraction of relative B(E2) values. In particular, the 2_{3}^{+}→0_{2}^{+} and 2_{3}^{+}→4_{1}^{+} transitions were observed for the first time. The results show excellent agreement with new microscopic large-scale shell-model calculations, and are discussed in terms of underlying shapes, as well as the role of neutron excitations across the N=40 gap. Enhanced axial shape asymmetry (triaxiality) is suggested to characterize ^{74}Zn in its ground state. Furthermore, an excited K=0 band with a significantly larger softness in its shape is identified. A shore of the N=40 "island of inversion" appears to manifest above Z=26, previously thought as its northern limit in the chart of the nuclides.

2.
Environ Res ; 233: 116431, 2023 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-37329946

RESUMEN

In this study, we synthesized silver nanoparticle-loaded cashew nut shell activated carbon (Ag/CNSAC). The synthesized samples were characterized by XRD, XPS, SEM with EDS, FT-IR, and BET analysis. The XRD, XPS, and EDS data provided convincing proof that Ag loaded on CNSAC is formed. The energy dispersive spectrum analysis and X-ray diffraction pattern both supported the face-centered cubic and amorphous structures of Ag/CNSAC. The SEM micrographs showed the inner surface development of Ag NPs and many tiny pores in CNSAC. The photodegradation of methylene blue (MB) dye by the Ag/CNSAC photocatalyst was investigated. This effective degradation of MB dye by Ag/CNSAC is attributed to the cooperative action of Ag as a photocatalyst and CNSAC as a catalytic support and adsorbent. In tests with gram-positive and negative bacteria including Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the as-synthesized Ag/CNSAC showed outstanding antibacterial efficiency. Additionally, this study demonstrates a workable procedure for creating an affordable and efficient Ag/CNSAC for the photocatalytic eradication of organic contaminants.


Asunto(s)
Nanopartículas del Metal , Plata , Plata/farmacología , Plata/química , Nanopartículas del Metal/química , Carbón Orgánico , Espectroscopía Infrarroja por Transformada de Fourier , Escherichia coli , Staphylococcus aureus , Antibacterianos/farmacología , Antibacterianos/química , Difracción de Rayos X
3.
J Trop Pediatr ; 67(4)2021 08 27.
Artículo en Inglés | MEDLINE | ID: mdl-34471923

RESUMEN

Chromobacterium violaceum, a facultative anaerobic proteobacterium, is isolated from water and soil in tropical areas and has been implicated in infections like septicemia, visceral abscesses, skin and soft tissue infections, meningitis and diarrhea. Chromobacterium violaceum sepsis, a rarely reported phenomenon has a very high mortality rate. Here, we report a unique case of Chromobacterium sepsis in an infant. A 48-day-old baby boy was referred to our institution with h/o fever, loose stools and reduced activity. He was intubated and referred to us in septic shock. Radiological investigations revealed multiple abscesses in the liver, spleen and kidneys. The infant was successfully treated with trimethoprim-sulfamethoxazole and ciprofloxacin.


Asunto(s)
Infecciones por Bacterias Gramnegativas , Sepsis , Antibacterianos/uso terapéutico , Chromobacterium , Ciprofloxacina/uso terapéutico , Infecciones por Bacterias Gramnegativas/diagnóstico , Infecciones por Bacterias Gramnegativas/tratamiento farmacológico , Humanos , Lactante , Masculino , Sepsis/diagnóstico , Sepsis/tratamiento farmacológico
5.
Phys Rev Lett ; 123(8): 082501, 2019 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-31491233

RESUMEN

The elusive ß^{-}p^{+} decay was observed in ^{11}Be by directly measuring the emitted protons and their energy distribution for the first time with the prototype Active Target Time Projection Chamber in an experiment performed at ISAC-TRIUMF. The measured ß^{-}p^{+} branching ratio is orders of magnitude larger than any previous theoretical model predicted. This can be explained by the presence of a narrow resonance in ^{11}B above the proton separation energy.

6.
Environ Monit Assess ; 191(Suppl 2): 393, 2019 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-31254076

RESUMEN

India has the largest number of dengue cases in the world, contributing approximately 34% of the global burden. The framework for a geospatially enabled early warning and adaptive response system (EWARS) was first proposed in 2008. It was meant to be a decision support system for enhancing traditional surveillance methods for preventing mosquito-borne diseases in India by utilizing remote sensing data and fuzzy logic-based mathematical predictive modeling. This conceptual paper presents a significant evolution of EWARS such that it synthesizes inputs from not only traditional surveillance and reporting systems for dengue but also from the public via participatory disease surveillance. Two smartphone-based applications have been developed to support EWARS. The first-MOSapp-allows field health workers to upload surveillance data and collect key data on environmental parameters by both direct observation and via portable microclimate stations. The second-DISapp-collects relevant information directly from the community to support participatory disease surveillance. It also gives the user a real-time estimate of the risk of exposure to dengue in proximity to their home and has an educational component that provides information on relevant preventive measures. Both applications utilize a new mosquito abundance measure-the mosquito perception index (MPI)-as reported by the user. These data streams will feed into the EWARS model to generate dynamic risk maps that can guide resource optimization and strengthen disease surveillance, prevention, and response. It is anticipated that such an approach can assist in addressing gaps in the current system of dengue surveillance and control in India.


Asunto(s)
Aedes/fisiología , Dengue/prevención & control , Aplicaciones Móviles , Mosquitos Vectores/fisiología , Animales , Dengue/epidemiología , Dengue/transmisión , Monitoreo Epidemiológico , Humanos , India/epidemiología , Modelos Teóricos , Medición de Riesgo
7.
Luminescence ; 33(1): 71-78, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-28786552

RESUMEN

This investigation reports, the effect of the concentration of erbium and lead ions on the physical, structural and optical properties of lead borosilicate glasses. These glasses were synthesized by the melt quench method. In the synthesis, the concentration of the erbium (Er3+ ) ion was varied in the order of 0.0, 0.1, 0.5, 1.0 and 2.0 mol% and lead (Pb2+ ) ion was varied in the order of 30, 29.9, 29.5, 29 and 28 mol%. The glasses were analyzed using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and UV-vis-NIR spectroscopy. From XRD, the amorphous nature of lead borosilicate glasses was confirmed. The functional groups which were present in the glasses have been identified by analyzing the FT-IR spectrum. From the absorption spectra, the oscillator strengths as well as the Judd-Ofelt (JO) intensity parameters were determined and compared with other hosts. The JO intensity parameters were further used to calculate certain radiative properties for the excited luminescent levels of Er3+ ion. From emission spectra, full width at half maxima (FWHM), stimulated emission cross-sections (σe ) and certain lasing parameters were evaluated and compared with reference host glasses. The lifetimes of 4 I13/2 excited level of Er3+ ion have also been recorded and analyzed. The calculated and experimental lifetimes were compared in terms of quantum efficiencies. From the photoluminescence analysis, the erbium doped lead borosilicate glasses well suited for optical fiber amplifiers are discussed.


Asunto(s)
Erbio/análisis , Tecnología de Fibra Óptica , Luminiscencia , Silicatos/química , Vidrio/química , Iones/análisis , Estructura Molecular , Teoría Cuántica
8.
Eur Arch Otorhinolaryngol ; 275(11): 2843-2850, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30225567

RESUMEN

Locally advanced oral cancers extending to infratemporal fossa (ITF) are a challenge to head and neck surgeons. These tumors are classified as T4b whenever the masticator space (MS), pterygoid muscles (PM), and pterygoid plates (PP) are involved according to AJCC classification. Until recently, these tumors were considered inoperable and treated only with palliative intent. However, a few studies in the last decade showed that many of these tumors could be resected with a reasonably favorable prognosis by compartment resection of ITF, particularly when the tumor was below sigmoid notch of mandible. A few studies attempted to downstage these tumors by neo-adjuvant chemotherapy before attempting resection. Oral Squamous cell carcinoma has a high prevalence in South India. Majority of these patients are females addicted to tobacco quid chewing and present with locally advanced disease. In this retrospective analysis, we evaluated the outcome of treatment of oral squamous cell carcinoma extending to ITF and staged T4b in 52 patients. All patients underwent Composite resection including compartment resection of ITF followed by adjuvant treatment. 20 patients had received neo-adjuvant chemotherapy. Pectoralis major myocutaneous flap was the mainstay of reconstruction. After mean follow-up of 2 years, 31 patients are alive and disease free. 14 patients had local recurrence in ITF and 2 patients had recurred in cervical nodes. 8 patients died due to disease and 6 are on palliative care. Neo-adjuvant chemotherapy did not benefit the outcome. Close margins of resection, extra nodal spread from lymph nodes and supra notch and involvement of posterior part of ITF were factors which predisposed to recurrence.


Asunto(s)
Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/terapia , Hospitales Rurales , Neoplasias de la Boca/patología , Neoplasias de la Boca/terapia , Centros de Atención Terciaria , Adulto , Anciano , Carcinoma de Células Escamosas/mortalidad , Quimioterapia Adyuvante , Femenino , Humanos , India , Ganglios Linfáticos/patología , Masculino , Mandíbula/patología , Persona de Mediana Edad , Neoplasias de la Boca/mortalidad , Músculos Pterigoideos/patología , Estudios Retrospectivos , Tasa de Supervivencia , Resultado del Tratamiento
9.
J Environ Manage ; 218: 602-612, 2018 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-29715669

RESUMEN

Water pollution by industrial and anthropogenic actives has become a serious threat to the environment. World Health Organization (WHO) has identified that lead and fluoride amid the environmental pollutants are most poisonous water contaminants with devastating impact on the human race. The present work proposes a study on economical bio-adsorbent based technique using exhausted coffee grounds in the removal of lead and fluoride contaminants from water. The exhausted coffee grounds gathered from industrial wastes have been acid-activated and examined for their adsorption capacity. The surface morphology and elemental characterization of pre-and-post adsorption operations by FESEM, EDX and FTIR spectral analysis confirmed the potential of the exhausted coffee ground as successful bio-sorbent. However, thermodynamic analysis confirmed the adsorption to be spontaneous physisorption with Langmuir mode of homogenous monolayer deposition. The kinetics of adsorption is well defined by pseudo second order model for both lead and fluoride. A significant quantity of lead and fluoride is removed from the synthetic contaminated water by the proposed bio-sorbent with the respective sorption capabilities of 61.6 mg/g and 9.05 mg/g. However, the developed bio-sorbent is also recyclable and is capable of removing the lead and fluoride from the domestic and industrial waste-water sources with an overall removal efficiency of about 90%.


Asunto(s)
Café , Fluoruros , Plomo , Purificación del Agua , Adsorción , Humanos , Concentración de Iones de Hidrógeno , Cinética , Termodinámica , Contaminantes Químicos del Agua
10.
J Food Sci Technol ; 54(4): 901-908, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28303041

RESUMEN

Chickpea starch was subjected to triple retrogradation cycle with time intervals of 24, 48 and 72 h. The impact on in vitro digestibility, functional, pasting and structural characteristics was investigated. Compared to native chickpea starch, the resistant starch (RS) content of triple retrograded starch was significantly increased with increased retrogradation time whereas slowly digestible starch content was decreased. Water binding capacity and solubility of triple retrograded starch were significantly increased whereas swelling power and pasting properties were decreased. Triple retrograded starches showed B type and B + V type crystalline structure. After triple retrogradation, the organised granular structure was disrupted, irregularly shaped particles were formed showing porous, coarse, filamentous network structure. FT-IR spectra perceived a slight change in percentage intensity of C-H stretch of triple retrograded starches (TRSs). Triple retrogradation was observed to be a promising methods for RS product.

11.
J Struct Biol ; 194(1): 18-28, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26796657

RESUMEN

Multidrug transcription regulator AcrR from Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 belongs to the tetracycline repressor family, one of the largest groups of bacterial transcription factors. The crystal structure of dimeric AcrR was determined and refined to 1.56Å resolution. The tertiary and quaternary structures of AcrR are similar to those of its homologs. The multidrug binding site was identified based on structural alignment with homologous proteins and has a di(hydroxyethyl)ether molecule bound. Residues from helices α4 and α7 shape the entry into this binding site. The structure of AcrR reveals that the extended helical conformation of helix α4 is stabilized by the hydrogen bond between Glu67 (helix α4) and Gln130 (helix α7). Based on the structural comparison with the closest homolog structure, the Escherichia coli AcrR, we propose that this hydrogen bond is responsible for control of the loop-to-helix transition within helix α4. This local conformational switch of helix α4 may be a key step in accessing the multidrug binding site and securing ligands at the binding site. Solution small-molecule binding studies suggest that AcrR binds ligands with their core chemical structure resembling the tetracyclic ring of cholesterol.


Asunto(s)
Proteínas Bacterianas/química , Dominios Proteicos , Estructura Secundaria de Proteína , Proteínas Represoras/química , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Sitios de Unión , Clonación Molecular , Cristalografía por Rayos X , Enlace de Hidrógeno , Ligandos , Modelos Moleculares , Unión Proteica , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Salmonella typhimurium/genética , Salmonella typhimurium/metabolismo , Homología de Secuencia de Ácido Nucleico
12.
PLoS Pathog ; 10(12): e1004532, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25502654

RESUMEN

Entamoeba histolytica is the etiological agent of human amoebic colitis and liver abscess, and causes a high level of morbidity and mortality worldwide, particularly in developing countries. There are a number of studies that have shown a crucial role for Ca2+ and its binding protein in amoebic biology. EhCaBP5 is one of the EF hand calcium-binding proteins of E. histolytica. We have determined the crystal structure of EhCaBP5 at 1.9 Šresolution in the Ca2+-bound state, which shows an unconventional mode of Ca2+ binding involving coordination to a closed yet canonical EF-hand motif. Structurally, EhCaBP5 is more similar to the essential light chain of myosin than to Calmodulin despite its somewhat greater sequence identity with Calmodulin. This structure-based analysis suggests that EhCaBP5 could be a light chain of myosin. Surface plasmon resonance studies confirmed this hypothesis, and in particular showed that EhCaBP5 interacts with the IQ motif of myosin 1B in calcium independent manner. It also appears from modelling of the EhCaBP5-IQ motif complex that EhCaBP5 undergoes a structural change in order to bind the IQ motif of myosin. This specific interaction was further confirmed by the observation that EhCaBP5 and myosin 1B are colocalized in E. histolytica during phagocytic cup formation. Immunoprecipitation of EhCaBP5 from total E. histolytica cellular extract also pulls out myosin 1B and this interaction was confirmed to be Ca2+ independent. Confocal imaging of E. histolytica showed that EhCaBP5 and myosin 1B are part of phagosomes. Overexpression of EhCaBP5 increases slight rate (∼20%) of phagosome formation, while suppression reduces the rate drastically (∼55%). Taken together, these experiments indicate that EhCaBP5 is likely to be the light chain of myosin 1B. Interestingly, EhCaBP5 is not present in the phagosome after its formation suggesting EhCaBP5 may be playing a regulatory role.


Asunto(s)
Proteínas de Unión al Calcio/química , Proteínas de Unión al Calcio/metabolismo , Entamoeba histolytica/metabolismo , Eritrocitos/patología , Eritrocitos/parasitología , Fagocitosis/fisiología , Secuencias de Aminoácidos , Calmodulina/química , Calmodulina/metabolismo , Cristalografía , Regulación hacia Abajo , Entamebiasis/metabolismo , Entamebiasis/patología , Entamebiasis/fisiopatología , Eritrocitos/metabolismo , Humanos , Miosinas/química , Miosinas/metabolismo , Fagosomas/fisiología
13.
Clin Genet ; 90(6): 496-508, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27146977

RESUMEN

Mucopolysaccharidoses (MPS), a subgroup of lysosomal storage disorders, are caused due to deficiency of specific lysosomal enzyme involved in catabolism of glycosaminoglycans. To date more than 200 pathogenic variants in the alpha-l-iduronidase (IDUA) for MPS I and ∼500 pathogenic variants in the iduronate-2-sulphatase (IDS) for MPS II have been reported worldwide. The mutation spectrum of MPS type I and MPS type II disorders in Indian population is not characterized yet. In this study, we carried out clinical, biochemical, molecular and in silico analyses to establish the mutation spectrum of MPS I and MPS II in the Indian population. We conducted molecular analysis for 60 MPS-affected patients [MPS I (n = 30) (Hurler syndrome = 17, Hurler-Scheie syndrome = 13), and MPS II (n = 30) (severe = 18, attenuated = 12)] and identified a total of 44 [MPS I (n = 22) and MPS II (n = 22)] different pathogenic variants comprising missense, nonsense, frameshift, gross deletions and splice site variants. A total of 20 [MPS I (n = 14), and MPS II (n = 6)] novel pathogenic sequence variants were identified in our patient cohort. We found that 32% of pathogenic variants detected in IDUA were recurrent and 25% in MPS II. This is the first study revealing the mutation spectrum of MPS I and MPS II patients in the Indian population.


Asunto(s)
Glicoproteínas/genética , Iduronidasa/genética , Mucopolisacaridosis II/genética , Mucopolisacaridosis I/genética , Mutación/genética , Adolescente , Niño , Preescolar , Femenino , Glicoproteínas/química , Humanos , Iduronidasa/química , India , Lactante , Masculino , Mucopolisacaridosis I/fisiopatología , Mucopolisacaridosis II/fisiopatología , Fenotipo , Conformación Proteica , Eliminación de Secuencia/genética , Relación Estructura-Actividad
14.
Nucleic Acids Res ; 42(12): 7894-910, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24878921

RESUMEN

DHH superfamily includes RecJ, nanoRNases (NrnA), cyclic nucleotide phosphodiesterases and pyrophosphatases. In this study, we have carried out in vitro and in vivo investigations on the bifunctional NrnA-homolog from Mycobacterium smegmatis, MSMEG_2630. The crystal structure of MSMEG_2630 was determined to 2.2-Å resolution and reveals a dimer consisting of two identical subunits with each subunit folding into an N-terminal DHH domain and a C-terminal DHHA1 domain. The overall structure and fold of the individual domains is similar to other members of DHH superfamily. However, MSMEG_2630 exhibits a distinct quaternary structure in contrast to other DHH phosphodiesterases. This novel mode of subunit packing and variations in the linker region that enlarge the domain interface are responsible for alternate recognitions of substrates in the bifunctional nanoRNases. MSMEG_2630 exhibits bifunctional 3'-5' exonuclease [on both deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) substrates] as well as CysQ-like phosphatase activity (on pAp) in vitro with a preference for nanoRNA substrates over single-stranded DNA of equivalent lengths. A transposon disruption of MSMEG_2630 in M. smegmatis causes growth impairment in the presence of various DNA-damaging agents. Further phylogenetic analysis and genome organization reveals clustering of bacterial nanoRNases into two distinct subfamilies with possible role in transcriptional and translational events during stress.


Asunto(s)
Proteínas Bacterianas/química , Mycobacterium smegmatis/enzimología , Ribonucleasas/química , Proteínas Bacterianas/clasificación , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Dominio Catalítico , Exonucleasas/metabolismo , Modelos Moleculares , Mutación , Operón , Hidrolasas Diéster Fosfóricas/metabolismo , Monoéster Fosfórico Hidrolasas/metabolismo , Filogenia , Estructura Terciaria de Proteína , Subunidades de Proteína/química , Subunidades de Proteína/clasificación , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , Ribonucleasas/clasificación , Ribonucleasas/genética , Ribonucleasas/metabolismo , Alineación de Secuencia
15.
Eur J Mass Spectrom (Chichester) ; 22(4): 181-191, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27882883

RESUMEN

A new class of Boc-N-protected hybrid peptides derived from L- Ala and ε6-Caa (L-Ala = L-Alanine, Caa = C-linked carboamino acid derived from D-xylose) have been studied by positive ion electrospray ionization (ESI) ion-trap tandem mass spectrometry (MS/MS). MSn spectra of protonated and alkali-cationized hybrid peptides produce characteristic fragmentation involving the peptide backbone, the tert-butyloxycarbonyl (Boc) group, and the side chain. The dipeptide positional isomers are differentiated by the collision-induced dissociation (CID) of the protonated and alkali-cationized peptides. The CID of [M + H]+ ion of Boc-NH-L-Ala-ε-Caa- OCH3 (1) shows a prominent [M + H - C4H8]+ ion, which is totally absent for its positional isomer Boc-NH-ε-Caa-L-Ala-OCH3 (6), which instead shows significant loss of t-butanol. The formation of the [M + Cat - C4H8]+ ion is totally absent and [M + Cat - Boc + H]+ is prominent in the CID of the [M + Cat]+ ion of Boc-NH-L-Ala-ε-Caa- OCH3 (1), whereas the former is highly abundant and the latter is of low abundance for its positional isomer Boc-NH-ε-Caa-L-Ala-OCH3 (6). It is observed that 'b' ions are abundant when oxazolone structures are formed through a five-membered cyclic transition state in tetra-, penta-, and hexapeptides and the cyclization process for larger 'b' ions led to an insignificant abundance. However, the significant 'b' ion is formed in ε,α-dipeptide, which may have a seven-membered substituted 2-oxoazepanium ion structure. The MSn spectra of [M + Cat - Boc + H]+ ions of these peptides are found to be significantly different to those of [M + H - Boc + H]+ ions. The CID spectra of [M + Cat - Boc + H]+ ions of peptide acids containing L-Ala at the C-terminus show an abundant N-terminal rearrangement ion, [bn + 17 + Cat]+, which is absent for the peptide acids containing ε-Caa at the C-terminus. Thus, the results of these hybrid peptides provide sequencing information, the structure of the cyclic intermediate involved in the formation of the rearrangement ion, and distinguish a pair of dipeptide positional isomers.


Asunto(s)
Álcalis/química , Dipéptidos/análisis , Dipéptidos/química , Espectrometría de Masa por Ionización de Electrospray/métodos , Espectrometría de Masas en Tándem/métodos , Cationes , Mescalina , Protones , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
16.
Nucleic Acids Res ; 41(6): 3659-72, 2013 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-23393191

RESUMEN

The linear chromosome of Streptomyces coelicolor contains two paralogous ssb genes, ssbA and ssbB. Following mutational analysis, we concluded that ssbA is essential, whereas ssbB plays a key role in chromosome segregation during sporulation. In the ssbB mutant, ∼30% of spores lacked DNA. The two ssb genes were expressed differently; in minimal medium, gene expression was prolonged for both genes and significantly upregulated for ssbB. The ssbA gene is transcribed as part of a polycistronic mRNA from two initiation sites, 163 bp and 75 bp upstream of the rpsF translational start codon. The ssbB gene is transcribed as a monocistronic mRNA, from an unusual promoter region, 73 bp upstream of the AUG codon. Distinctive DNA-binding affinities of single-stranded DNA-binding proteins monitored by tryptophan fluorescent quenching and electrophoretic mobility shift were observed. The crystal structure of SsbB at 1.7 Šresolution revealed a common OB-fold, lack of the clamp-like structure conserved in SsbA and previously unpublished S-S bridges between the A/B and C/D subunits. This is the first report of the determination of paralogous single-stranded DNA-binding protein structures from the same organism. Phylogenetic analysis revealed frequent duplication of ssb genes in Actinobacteria, whereas their strong retention suggests that they are involved in important cellular functions.


Asunto(s)
Proteínas Bacterianas/química , Proteínas Bacterianas/fisiología , Segregación Cromosómica , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/fisiología , Streptomyces coelicolor/genética , Actinobacteria/clasificación , Actinobacteria/genética , Proteínas Bacterianas/genética , Secuencia de Bases , ADN de Cadena Simple , Proteínas de Unión al ADN/genética , Modelos Moleculares , Datos de Secuencia Molecular , Filogenia , Regiones Promotoras Genéticas , Unión Proteica , Esporas Bacterianas/genética , Streptomyces coelicolor/metabolismo , Streptomyces coelicolor/fisiología , Relación Estructura-Actividad , Sitio de Iniciación de la Transcripción
17.
J Environ Manage ; 151: 160-6, 2015 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-25575343

RESUMEN

Endophytic bacteria have the potential to promote plant growth and heavy metal(loid) (HM) removal from contaminated soil. Pseudomonas koreensis AGB-1, isolated from roots of Miscanthus sinensis growing in mine-tailing soil, exhibited high tolerance to HMs and plant growth promoting traits. Transmission electron microscope (TEM) analysis revealed that AGB-1 sequestered HMs extracellularly and their accumulation was visible as dark metal complexes on bacterial surfaces and outside of the cells. DNA sequencing of HM resistance marker genes indicated high homology to the appropriate regions of the arsB, ACR3(1), aoxB, and bmtA determinants. Inoculating mining site soil with AGB-1 increased M. sinensis biomass by 54%, chlorophyll by 27%, and protein content by 28%. High superoxide dismutase and catalase activities, and the lower malondialdehyde content of plants growing in AGB-1-inoculated soil indicate reduced oxidative stress. Metal(loid) concentrations in roots and shoots of plants grown in inoculated soil were higher than those of the controls in pot trials with mine tailing soil. Results suggest that AGB-1 can be used in association with M. sinensis to promote phytostabilization and remediation of HM-contaminated sites.


Asunto(s)
Biodegradación Ambiental , Metales Pesados/química , Poaceae/metabolismo , Pseudomonas/metabolismo , Contaminantes del Suelo/química , Suelo/química , Biomasa , Contaminación Ambiental/análisis , Metales/análisis , Minería , Desarrollo de la Planta , Raíces de Plantas/metabolismo
18.
J Food Sci Technol ; 52(9): 5745-53, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26344988

RESUMEN

In the present study sweet potato starch was treated with hydrochloric acid or citric acid at 1 or 5 % concentration and its properties were investigated. Citric acid treatment resulted higher starch yield. Water holding capacity and water absorption index was increased with increased acid concentration. Emulsion properties improved at 5 % acid concentration. The DE value of acid-thinned sweet potato starches was ranged between 1.93 and 3.76 %. Hydrochloric acid treated starches displayed a higher fraction of amylose. X-ray diffraction (XRD) study revealed that all the starches displayed C-type crystalline pattern with varied crystallinity. FT-IR spectra perceived a slight change in percentage intensity of C-H stretch of citric acid modified starches. Starch granules tended to appear less smooth than the native starch granules after acid treatment in Scanning Electron Micrographs (SEM) with granule size ranging between 8.00 and 8.90 µm. A drastic decrease in the pasting profile was noticed in hydrochloric acid (5 %) treated starch. While 5 % citric acid treated starch exhibited higher pasting profile. Differential Scanning Calorimeter (DSC) showed that peak and conclusion gelatinisation temperatures increased with increase in hydrochloric acid or citric acid concentration. Hence citric acid was found to mimic the hydrochloric acid with some variation which suggests that it may have promising scope in acid modification.

19.
Extremophiles ; 18(4): 665-76, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24817611

RESUMEN

Bauxite residue (red mud), generated during the extraction of alumina from bauxite ore is characterized by high pH, high concentrations of soluble ions with low or virtually no organic matter. These extreme conditions along with numerous nutrient deficiencies, limit the microbial growth and vegetation establishment. In the present study, diversity of both cultivable and non-cultivable bacteria present in the red mud was investigated by 16S rDNA sequence analyses. The cultivable bacteria were identified as Agromyces indicus, Bacillus litoralis, B. anthracis, Chungangia koreensis, Kokuria flava, K. polaris, Microbacterium hominis, Planococcus plakortidis, Pseudomonas alcaliphila and Salinococcus roseus based on their 16S rDNA sequence analysis. These isolates were alkali tolerant, positive for one or more of the enzyme activities tested, able to produce organic acids and oxidize wide range of carbon substrates. For non-cultivable diversity of bacteria, DNA was extracted from the bauxite residue samples and 16S rDNA clone library was constructed. The 16S rDNA clones of this study showed affiliation to three major phyla predominant being betaproteobacteria (41.1%) followed by gammaproteobacteria (37.5%) and bacteroidetes (21.4%). We are reporting for the first time about the bacterial diversity of this unique and extreme environment.


Asunto(s)
Óxido de Aluminio/análisis , Bacteroidetes/aislamiento & purificación , Betaproteobacteria/aislamiento & purificación , Gammaproteobacteria/aislamiento & purificación , Residuos Industriales , Microbiota , Álcalis/análisis , Bacteroidetes/genética , Bacteroidetes/metabolismo , Betaproteobacteria/genética , Betaproteobacteria/metabolismo , Gammaproteobacteria/genética , Gammaproteobacteria/metabolismo , Estanques/química , Estanques/microbiología , ARN Ribosómico 16S/genética
20.
Biomed Chromatogr ; 28(6): 788-93, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24861745

RESUMEN

Nilutamide, a nonsteroidal anti-androgen drug, widely used in the treatment of prostate cancer, was subjected to hydrolytic, photolytic, thermal and oxidative stress conditions as per International Conference on Harmonization guidelines Q1A (R2). Nilutamide showed significant degradation under basic hydrolysis and photolytic stress conditions, while it was stable to neutral, acidic and thermal stress conditions. Five degradation products were formed and the chromatographic separation of nilutamide and its degradation products was achieved on a Waters C18 column (4.6 × 250 mm, 5 µm) using a mobile phase consisting of acetonitrile and 0.1% of formic acid in an isocratic elution method. All these degradation products were characterized by LC/MS/MS in negative ion mode, combined with accurate mass measurements. To assign likely structures for the observed degradation products, the fragmentation patterns of the deprotonated drug and its degradation products were compared. The in silico toxicity of the drug and its degradation products was also assessed using TOPKAT software. The carcinogenicity probability of the degradation products, DP-I-IV, was greater than that of nilutamide.


Asunto(s)
Antagonistas de Andrógenos/química , Imidazolidinas/química , Estabilidad de Medicamentos , Humanos , Concentración de Iones de Hidrógeno , Hidrólisis , Estructura Molecular , Fotólisis , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masas en Tándem
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