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1.
Braz. j. biol ; 84: e255605, 2024. tab
Artículo en Inglés | LILACS, VETINDEX | ID: biblio-1355882

RESUMEN

Abstract Combining ability analysis provides useful information for the selection of parents, also information regarding the nature and magnitude of involved gene actions. Crops improvement involves strategies for enhancing yield potentiality and quality components. Targeting the improvement of respective characters in bitter gourd, combining ability and genetic parameters for 19 characters were estimated from a 6×6 full diallel analysis technique. The results revealed that the variances due to general combining ability (GCA) and specific combining ability (SCA) were highly significant for most of the important characters. It indicated the importance of both additive and non-additive gene actions. GCA variances were higher in magnitude than SCA variances for all the characters studied indicating the predominance of the additive gene effects in their inheritance. The parent P2 (BG 009) appeared as the best general combiner for earliness; P1 (BG 006) for number of fruits, average single fruit weight and fruit yield; P4 (BG 027) for node number of first female flower and days to seed fruit maturity; P3 (BG 011) for fruit length and thickness of the fruit flesh; P5 (BG 033) for 100-seed weight; and P6 for number of nodes per main vine. The SCA effect as well as reciprocal effect was also significant for most of the important characters in different crosses.


Resumo A análise da capacidade de combinação fornece informações úteis para a seleção dos pais, também informações sobre a natureza e a magnitude das ações dos genes envolvidos. A melhoria das safras envolve estratégias para aumentar a potencialidade da produção e os componentes de qualidade. Visando ao aprimoramento dos respectivos caracteres em cabaça-amarga, capacidade de combinação e parâmetros genéticos para 19 caracteres, foram estimados a partir de uma técnica de análise dialélica completa 6 × 6. Os resultados revelaram que as variâncias, devido à capacidade geral de combinação (GCA) e capacidade específica de combinação (SCA), foram altamente significativas para a maioria dos caracteres importantes. Indicou a importância das ações gênicas aditivas e não aditivas. As variâncias GCA foram maiores em magnitude do que as variâncias SCA para todos os caracteres estudados, indicando a predominância dos efeitos do gene aditivo em sua herança. O pai P2 (BG 009) apareceu como o melhor combinador geral para o início; P1 (BG 006) para número de frutos, peso médio de um único fruto e produção de frutos; P4 (BG 027) para número de nó da primeira flor fêmea e dias para a maturidade do fruto da semente; P3 (BG 011) para comprimento do fruto e espessura da polpa do fruto; P5 (BG 033) para peso de 100 sementes; e P6 para o número de nós por videira principal. O efeito SCA, bem como o efeito recíproco, também foi significativo para a maioria dos personagens importantes em cruzamentos diferentes.


Asunto(s)
Momordica charantia , Productos Agrícolas , Flores , Mejoramiento de la Calidad , Frutas/genética
2.
Braz. j. biol ; 842024.
Artículo en Inglés | LILACS-Express | LILACS, VETINDEX | ID: biblio-1469309

RESUMEN

Abstract Combining ability analysis provides useful information for the selection of parents, also information regarding the nature and magnitude of involved gene actions. Crops improvement involves strategies for enhancing yield potentiality and quality components. Targeting the improvement of respective characters in bitter gourd, combining ability and genetic parameters for 19 characters were estimated from a 6×6 full diallel analysis technique. The results revealed that the variances due to general combining ability (GCA) and specific combining ability (SCA) were highly significant for most of the important characters. It indicated the importance of both additive and non-additive gene actions. GCA variances were higher in magnitude than SCA variances for all the characters studied indicating the predominance of the additive gene effects in their inheritance. The parent P2 (BG 009) appeared as the best general combiner for earliness; P1 (BG 006) for number of fruits, average single fruit weight and fruit yield; P4 (BG 027) for node number of first female flower and days to seed fruit maturity; P3 (BG 011) for fruit length and thickness of the fruit flesh; P5 (BG 033) for 100-seed weight; and P6 for number of nodes per main vine. The SCA effect as well as reciprocal effect was also significant for most of the important characters in different crosses.


Resumo A análise da capacidade de combinação fornece informações úteis para a seleção dos pais, também informações sobre a natureza e a magnitude das ações dos genes envolvidos. A melhoria das safras envolve estratégias para aumentar a potencialidade da produção e os componentes de qualidade. Visando ao aprimoramento dos respectivos caracteres em cabaça-amarga, capacidade de combinação e parâmetros genéticos para 19 caracteres, foram estimados a partir de uma técnica de análise dialélica completa 6 × 6. Os resultados revelaram que as variâncias, devido à capacidade geral de combinação (GCA) e capacidade específica de combinação (SCA), foram altamente significativas para a maioria dos caracteres importantes. Indicou a importância das ações gênicas aditivas e não aditivas. As variâncias GCA foram maiores em magnitude do que as variâncias SCA para todos os caracteres estudados, indicando a predominância dos efeitos do gene aditivo em sua herança. O pai P2 (BG 009) apareceu como o melhor combinador geral para o início; P1 (BG 006) para número de frutos, peso médio de um único fruto e produção de frutos; P4 (BG 027) para número de nó da primeira flor fêmea e dias para a maturidade do fruto da semente; P3 (BG 011) para comprimento do fruto e espessura da polpa do fruto; P5 (BG 033) para peso de 100 sementes; e P6 para o número de nós por videira principal. O efeito SCA, bem como o efeito recíproco, também foi significativo para a maioria dos personagens importantes em cruzamentos diferentes.

3.
Indian J Otolaryngol Head Neck Surg ; 75(2): 1105-1108, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37275026

RESUMEN

Wegener's granulomatosis is a necrotising vasculitis affecting both arterioles and venules. The classical triad involves acute inflammation of upper airway along with inflammation of lower respiratory tract and renal involvement, however other organ system may also be affected. Our patient presented with severe unilateral earache, ear discharge, hearing loss and ipsilateral facial nerve palsy as the manifestations of the disease, which are rarely reported in medical literature1.

4.
Adv Exp Med Biol ; 1379: 115-138, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35760990

RESUMEN

The tumor microenvironment (TME) is like the Referee of a soccer match who has constant eyes on the activity of all players, such as cells, acellular stroma components, and signaling molecules for the successful completion of the game, that is, tumorigenesis. The cooperation among all the "team members" determines the characteristics of tumor, such as the hypoxic and acidic niche, stiffer mechanical properties, or dilated vasculature. Like in soccer, each TME is different. This heterogeneity makes it challenging to fully understand the intratumor dynamics, particularly among different tumor subpopulations and their role in therapeutic response or resistance. Further, during metastasis, tumor cells can disseminate to a secondary organ, a critical event responsible for approximately 90% of the deaths in cancer patients. The recapitulation of the rapidly changing TME in the laboratory is crucial to improve patients' prognosis for unraveling key mechanisms of tumorigenesis and developing better drugs. Hence, in this chapter, we provide an overview of the characteristic features of the TME and how to model them, followed by a brief description of the limitations of existing in vitro platforms. Finally, various attempts at simulating the TME using microfluidic platforms are highlighted. The chapter ends with the concerns that need to be addressed for designing more realistic and predictive tumor-on-a-chip platforms.


Asunto(s)
Dispositivos Laboratorio en un Chip , Neoplasias , Carcinogénesis , Humanos , Microfluídica , Neoplasias/patología , Microambiente Tumoral
5.
Braz J Biol ; 84: e255605, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35019109

RESUMEN

Combining ability analysis provides useful information for the selection of parents, also information regarding the nature and magnitude of involved gene actions. Crops improvement involves strategies for enhancing yield potentiality and quality components. Targeting the improvement of respective characters in bitter gourd, combining ability and genetic parameters for 19 characters were estimated from a 6×6 full diallel analysis technique. The results revealed that the variances due to general combining ability (GCA) and specific combining ability (SCA) were highly significant for most of the important characters. It indicated the importance of both additive and non-additive gene actions. GCA variances were higher in magnitude than SCA variances for all the characters studied indicating the predominance of the additive gene effects in their inheritance. The parent P2 (BG 009) appeared as the best general combiner for earliness; P1 (BG 006) for number of fruits, average single fruit weight and fruit yield; P4 (BG 027) for node number of first female flower and days to seed fruit maturity; P3 (BG 011) for fruit length and thickness of the fruit flesh; P5 (BG 033) for 100-seed weight; and P6 for number of nodes per main vine. The SCA effect as well as reciprocal effect was also significant for most of the important characters in different crosses.


Asunto(s)
Momordica charantia , Productos Agrícolas , Flores , Frutas/genética , Mejoramiento de la Calidad
6.
ACS Appl Mater Interfaces ; 11(16): 14548-14559, 2019 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-30943004

RESUMEN

Osteosarcoma is one of the most common metastatic bone cancers, which results in significant morbidity and mortality. Unfolding of effectual therapeutic strategies against osteosarcoma is impeded because of the absence of adequate animal models, which can truly recapitulate disease biology of humans. Tissue engineering provides an opportunity to develop physiologically relevant, reproducible, and tunable in vitro platforms to investigate the interactions of osteosarcoma cells with its microenvironment. Adipose-derived stem cells (ASCs) are detected adjacent to osteosarcoma masses and are considered to have protumor effects. Hence, the present study focuses on investigating the role of reactive ASCs in formation of spheroids of osteosarcoma cells (Saos 2) within a three-dimensional (3D) niche, which is created using gellan gum (GG)-silk fibroin. By modifying the blending ratio of GG-silk, the optimum stiffness of the resultant hydrogels such as GG and GG75: S25 is obtained for cancer spheroid formation. This work indicates that the co-existence of cancer and stem cells can form a spheroid, the hallmark of cancer, only in particular microenvironment stiffness. The incorporation of fibrillar silk fibroin within the hydrophilic network of GG in GG75: S25 spongy-like hydrogels closely mimics the stiffness of commercially established cancer biomaterials (e.g., Matrigel, HyStem). The GG75: S25 hydrogel maintains the metabolically active construct for a longer time with elevated expression of osteopontin, osteocalcin, RUNX 2, and bone sialoprotein genes, the biomarkers of osteosarcoma, compared to GG. The GG75: S25 construct also exhibits intense alkaline phosphatase expression in immunohistochemistry compared to GG, indicating itspotentiality to serve as biomimetic niche to model osteosarcoma. Taken together, the GG-silk fibroin-blended spongy-like hydrogel is envisioned as an alternative low-cost platform for 3D cancer modeling.


Asunto(s)
Adipocitos/metabolismo , Tejido Adiposo/metabolismo , Neoplasias Óseas/metabolismo , Fibroínas/química , Hidrogeles/química , Modelos Biológicos , Osteosarcoma/metabolismo , Esferoides Celulares/metabolismo , Células Madre/metabolismo , Andamios del Tejido/química , Adipocitos/patología , Tejido Adiposo/patología , Neoplasias Óseas/patología , Línea Celular Tumoral , Humanos , Osteosarcoma/patología , Esferoides Celulares/patología , Células Madre/patología , Ingeniería de Tejidos
7.
Biomed Mater ; 13(4): 044101, 2018 04 11.
Artículo en Inglés | MEDLINE | ID: mdl-29489458

RESUMEN

The assembly of natural proteinaceous biopolymers into macro-scale architectures is of great importance in synthetic biology, soft-material science and regenerative therapy. The self-assembly of protein tends to be limited due to anisotropic interactions among protein molecules, poor solubility and stability. Here, we introduce a unique platform to self-immobilize diverse proteins (fibrous and globular, positively and negatively charged, low and high molecular weight) using silicon surfaces with pendant -NH2 groups via a facile one step diffusion limited aggregation (DLA) method. All the experimental proteins (type I collagen, bovine serum albumin and cytochrome C) self-assemble into seaweed-like branched dendritic architectures via classical DLA in the absence of any electrolytes. The notable differences in branching architectures are due to dissimilarities in protein colloidal sub-units, which is typical for each protein type, along with the heterogeneous distribution of surface -NH2 groups. Fractal analysis of assembled structures is used to explain the underlying route of fractal deposition; which concludes how proteins with different functionality can yield similar assembly. Further, the nano-micro-structured surfaces can be used to provide functional topographical cues to study cellular responses, as demonstrated using rat bone marrow stem cells. The results indicate that the immobilization of proteins via DLA does not affect functionality, instead serving as topographical cues to guide cell morphology. This indicates a promising design strategy at the tissue-material interface and is anticipated to guide future surface modifications. A cost-effective standard templating strategy is therefore proposed for fundamental and applied particle aggregation studies, which can be used at multiple length scales for biomaterial design and surface reformation.


Asunto(s)
Biopolímeros/química , Colágeno/química , Citocromos c/química , Medicina Regenerativa/métodos , Albúmina Sérica/química , Algoritmos , Aminas/química , Animales , Anisotropía , Materiales Biocompatibles/química , Células de la Médula Ósea/citología , Adhesión Celular , Difusión , Fractales , Masculino , Ensayo de Materiales , Microscopía de Fuerza Atómica , Microscopía Electrónica de Rastreo , Nanoestructuras/química , Ratas , Silicio/química , Dióxido de Silicio/química , Solubilidad , Propiedades de Superficie , Biología Sintética
8.
Hernia ; 21(1): 125-137, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27038052

RESUMEN

BACKGROUND: Adhesion formation remains a major complication following hernia repair surgery. Physical barriers though effective for adhesion prevention in clinical settings are associated with major disadvantages, therefore, needs further investigation. This study evaluates silk fibroin hydrogel as a physical barrier on polypropylene mesh for the prevention of adhesion following ventral hernia repair. STUDY DESIGN: Peritoneal explants were cultured on silk fibroin scaffold to evaluate its support for mesothelial cell growth. Full thickness uniform sized defects were created on the ventral abdominal wall of rabbits, and the defects were covered either with silk hydrogel coated polypropylene mesh or with plain polypropylene mesh as a control. The animals were killed after 1 month, and the adhesion formation was graded; healing response of peritoneum was evaluated by immunohistochemistry with calretinin, collagen staining of peritoneal sections, and expression of PCNA, collagen-I, TNFα, IL6 by real time PCR; and its adverse effect if any was determined. RESULTS: Silk fibroin scaffold showed excellent support for peritoneal cell growth in vitro and the cells expressed calretinin. A remarkable prevention of adhesion formation was observed in the animals implanted with silk hydrogel coated mesh compared to the control group; in these animals peritoneal healing was complete and predominantly by mesothelial cells with minimum fibrotic changes. Expression of inflammatory cytokines decreased compared to control animals, histology of abdominal organs, haematological and blood biochemical parameters remained normal. CONCLUSION: Therefore, silk hydrogel coating of polypropylene mesh can improve peritoneal healing, minimize adhesion formation, is safe and can augment the outcome of hernia surgery.


Asunto(s)
Fibroínas/administración & dosificación , Hernia Ventral/cirugía , Herniorrafia/efectos adversos , Hidrogel de Polietilenoglicol-Dimetacrilato/administración & dosificación , Mallas Quirúrgicas/efectos adversos , Adherencias Tisulares/prevención & control , Pared Abdominal/patología , Pared Abdominal/cirugía , Animales , Materiales Biocompatibles Revestidos , Herniorrafia/instrumentación , Microscopía Electrónica de Rastreo , Peritoneo/patología , Peritoneo/cirugía , Peritoneo/ultraestructura , Polipropilenos/efectos adversos , Conejos , Ratas , Ratas Sprague-Dawley , Seda/administración & dosificación , Adherencias Tisulares/etiología , Adherencias Tisulares/patología , Andamios del Tejido , Cicatrización de Heridas/fisiología
9.
Biochim Biophys Acta ; 1840(11): 3264-76, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25088798

RESUMEN

BACKGROUND: Microbial resistance to antibiotics has triggered the development of nanoscale materials as an alternative strategy. To stabilize these particles an inert support is needed. METHOD: Porous nanomullite developed by sol-gel route is loaded with copper and silver nanoparticle by simple adsorption method. These nanocomposites are characterized using XRD, FTIR, TEM, SEM, EDAX and UV-visible spectrophotometer. Antibacterial activity of these nanocomposites against Gram positive and Gram negative bacteria are performed by bactericidal kinetics, flow cytometry and MTT assay. The underlying mechanisms behind the antimicrobial property and cell death are also investigated by EPR spectroscopy, intracellular ROS measurement and ß-galactosidase assay. The cytocompatibility of the nanocomposites is investigated by cell viability (MTT), proliferation (Alamar blue) and wound healing assay of mammalian fibroblast cell line. RESULTS: Nanocomposites show a fairly uniform distribution of metal nanoparticle within mullite matrix. They show excellent antibacterial activity. Metal ions/nanoparticle is found to be released from the materials (CM and SM). Treated cells manifested high intracellular oxidative stress and ß-galactosidase activity in the growth medium. The effect of nanocomposites on mammalian cell line depends on exposure time and concentration. The scratch assay shows normal cell migration with respect to control. CONCLUSION: The fabricated nanoparticles possess diverse antimicrobial mechanism and exhibit good cytocompatibility along with wound healing characteristics in mouse fibroblast cell line (L929). GENERAL SIGNIFICANCE: The newly synthesized materials are promising candidates for the development of antimicrobial ceramic coatings for biomedical devices and therapeutic applications.

10.
AJNR Am J Neuroradiol ; 32(8): 1420-5, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21885713

RESUMEN

BACKGROUND AND PURPOSE: fMRI is increasingly used in neurosurgery to preoperatively identify areas of eloquent cortex. Our study evaluated the efficacy of clinical fMRI by analyzing the relationship between the distance from the tumor border to the area of functional activation (LAD) and patient pre- and postoperative morbidity and mortality. MATERIALS AND METHODS: The study included patients with diagnosis of primary or metastatic brain tumor who underwent preoperative fMRI-based motor mapping (n=74) and/or language mapping (n=77). The impact of LAD and other variables collected from patient records was analyzed with respect to functional deficits in terms of morbidity (paresis and aphasia) and mortality. RESULTS: Significant relationships were found between motor and language LAD and the existence of either pre- or postoperative motor (P < .001) and language deficits (P=.009). Increasing age was associated with motor and language deficits (P=.02 and P=.04 respectively). Right-handedness was related to language deficits (P=.05). Survival analysis revealed that pre- and postoperative deficits, grade, tumor location, and LAD predicted mortality. Motor deficits increased linearly as the distance from the tumor to the primary sensorimotor cortex decreased. Language deficits increased exponentially as the distance from the tumor to the language areas decreased below 1 cm. Postoperative mortality analysis showed an interaction effect between motor or language LAD and mortality predictors (grade and tumor location, respectively). CONCLUSIONS: These findings indicate that tumors may affect language and motor function differently depending on tumor LAD. Overall, the data support the use of fMRI as a tool to evaluate patient prognosis and are directly applicable to neurosurgical planning.


Asunto(s)
Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/cirugía , Imagen por Resonancia Magnética , Complicaciones Posoperatorias/epidemiología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Complicaciones Posoperatorias/mortalidad , Valor Predictivo de las Pruebas , Pronóstico , Estudios Retrospectivos , Análisis de Supervivencia
11.
Indian J Med Res ; 132: 15-30, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20693585

RESUMEN

Treatment of delayed union, malunion, and nonunion is a challenge to the orthopaedic surgeons in veterinary and human fields. Apart from restoration of alignment and stable fixation, in many cases adjunctive measures such as bone-grafting or use of bone-graft substitutes are of paramount importance. Bone-graft materials usually have one or more components: an osteoconductive matrix, which acts as scaffold to new bone growth; osteoinductive proteins, which support mitogenesis of undifferentiated cells; and osteogenic cells, which are capable of forming bone in the appropriate environment. Autologous bone remains the "gold standard" for stimulating bone repair and regeneration, but its availability may be limited and the procedure to harvest the material is associated with complications. Bone-graft substitutes can either substitute autologous bone graft or expand an existing amount of autologous bone graft. We review the currently available bone graft and graft substitutes for the novel therapeutic approaches in clinical setting of orthopaedic surgery.


Asunto(s)
Desarrollo Óseo/fisiología , Regeneración Ósea/fisiología , Sustitutos de Huesos , Trasplante Óseo/métodos , Terapia Genética/métodos , Trasplante de Células Madre Mesenquimatosas/métodos , Procedimientos Ortopédicos/métodos , Fosfatos de Calcio , Sulfato de Calcio , Cerámica/uso terapéutico , Durapatita , Humanos , Péptidos y Proteínas de Señalización Intercelular/uso terapéutico , Polímeros/uso terapéutico
12.
J Mater Sci Mater Med ; 21(11): 2955-69, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20644982

RESUMEN

The inability to maintain high concentrations of antibiotic at the site of infection for an extended period of time along with dead space management is still the driving challenge in treatment of osteomyelitis. Porous bioactive ceramics such as hydroxyapatite (HAp) and beta-tri calcium phosphate (ß-TCP) were some of the alternatives to be used as local drug delivery system. However, high porosity and high interconnectivity of pores in the scaffolds play a pivotal role in the drug release and bone resorption. Ceftriaxone is a cephalosporin that has lost its clinical popularity. But has recently been reported to exhibit better bactericidal activity in vitro and reduced probability of resistance development, in combination with sulbactam, a ß-lactamase inhibitor. In this article, a novel approach of forming HAp and pure ß-TCP based porous scaffolds by applying together starch consolidation with foaming method was used. For the purpose, pure HAp and ß-TCP were prepared in the laboratory and after thorough characterization (including XRD, FTIR, particle size distribution, etc.) the powders were used for scaffold fabrication. The ability of these scaffolds to release drugs suitably for osteomyelitis was studied in vitro. The results of the study indicated that HAp exhibited better drug release profile than ß-TCP when drug was used alone indicating the high influence of the carrier material. However, this restriction got relaxed when a bilayered scaffold was formed using chitosan along with the drug. SEM studies along with EDAX on the drug-chitosan bilayered scaffold showed closest apposition of this combination to the calcium phosphate surface.


Asunto(s)
Fosfatos de Calcio/química , Quitosano/química , Portadores de Fármacos/síntesis química , Durapatita/química , Polímeros/síntesis química , Almidón/farmacología , Andamios del Tejido/química , Materiales Biocompatibles Revestidos/síntesis química , Materiales Biocompatibles Revestidos/química , Materiales Biocompatibles Revestidos/farmacología , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos/métodos , Polímeros/química , Porosidad , Polvos/síntesis química , Polvos/química , Espectroscopía Infrarroja por Transformada de Fourier , Almidón/química , Sustancias Viscoelásticas/química , Difracción de Rayos X
13.
Phys Rev E Stat Nonlin Soft Matter Phys ; 81(1 Pt 1): 010702, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20365313

RESUMEN

We measured the splay (K11) and bend (K33) elastic constants in the nematic phase of a bent-core liquid crystal. In the vicinity of the nematic-isotropic transition temperature K33 is proportional to the square of the order parameter. In the nematic range K11 increases monotonically with decreasing temperature, whereas K33 is practically independent of temperature and is smaller than K11 . K33 exhibits a pretransitional slow divergence toward the transition temperature to the smectic phase and becomes slightly larger than K11. The small K33 is explained on the basis of strong coupling of the bent shape of the molecules with the bend distortion.

14.
Biochemistry (Mosc) ; 75(3): 375-81, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20370616

RESUMEN

We report studies on an L-asparaginase from Pyrococcus furiosus, cloned and expressed in Escherichia coli and purified to homogeneity. Protein stability and enzyme kinetic parameters were determined. The enzyme was found to be thermostable, natively dimeric, and glutaminase-free, with optimum activity at pH 9.0. It showed a K(m) of 12 mM and a substrate inhibition profile above 20 mM L-asparagine. Urea could not induce unfolding and enzyme inactivation; however, with guanidine hydrochloride (GdnCl) a two-state unfolding pattern was observed. Reduced activity and an altered near-UV-CD signal for protein at low GdnCl concentration (1 M) suggested tertiary structural changes at the enzyme active site. A homology three-dimensional model was developed and the structural information was combined with activity and stability data to give functional clues about the asparaginase.


Asunto(s)
Asparaginasa/metabolismo , Pyrococcus furiosus/enzimología , Secuencia de Bases , Cartilla de ADN , Estabilidad de Enzimas , Concentración de Iones de Hidrógeno , Cinética
15.
Eur Phys J E Soft Matter ; 31(2): 145-52, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20195691

RESUMEN

We report measurements of the temperature variations of the optical birefringence in the nematic (N) and partial bilayer SmA (SmA(d)) phases in 4-n-octyloxy 4(')-cyanobiphenyl made of rod-like (R) molecules and five mixtures of this compound with 1,3-phenylene bis[4-(3-methylbenzoyloxy)] 4(')-n-dodecylbiphenyl 4(')-carboxylate, made of bent-core (BC) molecules. The birefringence decreases with the concentration x of the BC molecules but the macroscopic order parameter initially decreases upto 11 mol% of BC molecules and subsequently increases with x. This is attributed to the possible formation of polar clusters of BC molecules. Orientation of BC molecules changes between the N and SmA(d) phases and the birefringence data in the two phases imply that the kink angle of the BC molecules is approximately 90 degrees rather than approximately 110 degrees as obtained from calculations which minimize the energy of the molecule. IR spectroscopic measurements on the mixture with 11 mol% of BC molecules have been used to estimate the molecular order parameter S of the R molecules, and to provide additional support for a relatively small kink angle of BC molecules.


Asunto(s)
Mezclas Complejas/química , Cristales Líquidos/química , Modelos Químicos , Modelos Moleculares , Nanoestructuras/química , Nanoestructuras/ultraestructura , Simulación por Computador , Conformación Molecular , Tamaño de la Partícula
16.
Phys Rev E Stat Nonlin Soft Matter Phys ; 82(5 Pt 1): 050701, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21230425

RESUMEN

We measured the splay (K11) and bend (K33) elastic constants in the nematic phase of a liquid crystal with T-shaped molecules. We find that the ratio, K33/K11 ≃1 in the entire nematic range except very close to the nematic to Sm-A (SN) transition. Both K33 and K11 show pretransitional divergence as the SN transition is approached from higher temperature. The ratio, K33/K11 suggests that the length (L) to effective width (D) ratio (i.e., L/D ) is significantly smaller due to the presence of long and flexible lateral group, compared to that of rigid rodlike molecules. It is argued that apart from the extra contribution to the elasticity the long and flexible lateral group also has a significant contribution to the suppression of the splay fluctuations in the onset of smectic short-range fluctuation. The structure of the Sm-A phase is investigated by using small angle x-ray diffraction, and a possible arrangement of the molecules in the Sm-A layer is proposed.

17.
Indian J Microbiol ; 49(2): 120-7, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23100760

RESUMEN

The native population of phosphate solubilizing bacteria (PSB) was studied in the rhizosphere of chickpea, mustard and wheat grown in different regions of Haryana. A total of 193 PSB were isolated from 245 rhizospheric samples collected from south-west and north-east zones. The PSB count showed large variations (3-67 × 10(5)cfu/g) and biodiversity within the crop and place of sampling. Using biochemical analysis, the isolates were tentatively identified as belonging to four genera, Pseudomonas, Aeromonas, Klebsiella and Enterobacter. Phosphate solubilization of these isolates varied from 5.9 to 123.8% and 2.2 to 227.2 µg/ml in solid and liquid Pikovskaya's medium, respectively. Based on their morphological traits, all the isolates were placed into 20 groups, majority of them falling in the group having white, round and gummy colonies, irrespective of the crop or the region. The intrinsic antibiotic resistance pattern showed large variations among the isolates and most of the isolates were resistant to streptomycin, ampicillin and penicillin. The highest PSB number and greatest variability were found in the rhizosphere of chickpea, followed by wheat and then mustard.

18.
Int J Antimicrob Agents ; 29(1): 73-8, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17156978

RESUMEN

There has been a marked expansion in the discovery of new antifungal peptides. This paper describes a novel dodecapeptide, H-Arg-Trp-Trp-Arg-D-Trp-D-Phe-Ile-D-Phe-His-Trp-Arg-Trp-NH(2), derived from a previously described nonapeptide and synthesized by the combinatorial approach. Further, interaction of this peptide with antifungals such as amphotericin B, flucytosine and fluconazole was studied by checkerboard analysis and time-kill assay to obtain the dynamic picture with respect to time. The best synergistic activity was observed with a combination of peptide and fluconazole, followed by peptide and flucytosine.


Asunto(s)
Antifúngicos/farmacología , Hongos/efectos de los fármacos , Oligopéptidos/farmacología , Secuencia de Aminoácidos , Anfotericina B/farmacología , Animales , Antifúngicos/síntesis química , Antifúngicos/química , Aspergillus fumigatus/efectos de los fármacos , Candida albicans/efectos de los fármacos , Técnicas Químicas Combinatorias , Cryptococcus neoformans/efectos de los fármacos , Sinergismo Farmacológico , Eritrocitos/efectos de los fármacos , Fluconazol/farmacología , Flucitosina/farmacología , Hemólisis/efectos de los fármacos , Concentración 50 Inhibidora , Pruebas de Sensibilidad Microbiana , Oligopéptidos/síntesis química , Oligopéptidos/química , Conejos
19.
Indian J Microbiol ; 47(1): 26-9, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23100635

RESUMEN

Pretreatment of paddy straw with 2% sodium hydroxide at 15 psi for 1 h resulted in 83% delignification. The hydrolysis of alkali treated paddy straw with a commercial preparation of cellulase for 2 h at 50°C resulted in release of 65% total reducing sugars. Maximum sugars were released at enzyme loading of 1.5% (v/v). The fermentation of hydrolysate supplemented with nutrients by S. cerevisiae resulted in the production of 20-30 g L(-1) ethanol after 48 h incubation which was further improved with addition of yeast nitrogen base and inoculated with 1% (w/v) yeast cells.

20.
Int J Antimicrob Agents ; 25(4): 313-20, 2005 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-15784311

RESUMEN

It is becoming clear that antimicrobial peptides are important components of the innate defences of all species of life. They kill very rapidly, do not easily select resistant mutants and are synergistic with potentially toxic conventional therapeutic agents against microbes. This paper describes an attempt to expand a lead hexapeptide motif synthesized through combinatorial approach. A cationic peptide H-Arg-Trp-Trp-Arg-D-Trp-D-Phe-Ile-D-Phe-His-NH2 was found to be active with a therapeutic index of >17. I was proposed that the combination of peptide with known antifungal agents may identify synergistic combinations that would ideally reduce the dosage of conventional antifungals as well as their associated toxicity. Nine different pathogenic strains and species of Candida and two of Cryptococcus neoformans were employed in chequerboard method and in time kill assays to evaluate the synergistic effect of the lead peptide in combination with amphotericin B, 5-flucytosine, ketoconazole and fluconazole. We found synergistic interaction between the peptide and all four drugs against Cryptococcus isolates whilst both synergistic and additive combinations occurred when Candida isolates were used.


Asunto(s)
Antifúngicos/farmacología , Candida/efectos de los fármacos , Cryptococcus neoformans/efectos de los fármacos , Oligopéptidos/farmacología , Secuencias de Aminoácidos , Antifúngicos/síntesis química , Antifúngicos/química , Candida/clasificación , Candida albicans/efectos de los fármacos , Técnicas Químicas Combinatorias , Farmacorresistencia Fúngica , Sinergismo Farmacológico , Humanos , Pruebas de Sensibilidad Microbiana/métodos , Oligopéptidos/síntesis química , Oligopéptidos/química , Biblioteca de Péptidos , Relación Estructura-Actividad
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