The RecX protein interacts with the RecA protein and modulates its activity in Herbaspirillum seropedicae

DNA repair is crucial to the survival of all organisms. The bacterial RecA protein is a central component in the SOS response and in recombinational and SOS DNA repairs. The RecX protein has been characterized as a negative modulator of RecA activity in many bacteria. The recA and recX genes of Herbaspirillum seropedicae constitute a single operon, and evidence suggests that RecX participates in SOS repair. In the present study, we show that the H. seropedicae RecX protein (RecX Hs) can interact with the H. seropedicaeRecA protein (RecA Hs) and that RecA Hs possesses ATP binding, ATP hydrolyzing and DNA strand exchange activities. RecX Hs inhibited 90% of the RecA Hs DNA strand exchange activity even when present in a 50-fold lower molar concentration than RecA Hs. RecA Hs ATP binding was not affected by the addition of RecX, but the ATPase activity was reduced. When RecX Hs was present before the formation of RecA filaments (RecA-ssDNA), inhibition of ATPase activity was substantially reduced and excess ssDNA also partially suppressed this inhibition. The results suggest that the RecX Hs protein negatively modulates the RecA Hs activities by protein-protein interactions and also by DNA-protein interactions.

Rat vas deferens SERCA2 is modulated by Ca2+/calmodulin protein kinase II-mediated phosphorylation

Ca2+ pumps are important players in smooth muscle contraction. Nevertheless, little information is available about these pumps in the vas deferens. We have determined which subtype of sarco(endo)plasmic reticulum Ca2+-ATPase isoform (SERCA) is expressed in rat vas deferens (RVD) and its modulation by calmodulin (CaM)-dependent mechanisms. The thapsigargin-sensitive Ca2+-ATPase from a membrane fraction containing the highest SERCA levels in the RVD homogenate has the same molecular mass (∼115 kDa) as that of SERCA2 from the rat cerebellum. It has a very high affinity for Ca2+ (Ca0.5 = 780 nM) and a low sensitivity to vanadate (IC50 = 41 µM). These facts indicate that SERCA2 is present in the RVD. Immunoblotting for CaM and Ca2+/calmodulin-dependent protein kinase II (CaMKII) showed the expression of these two regulatory proteins. Ca2+ and CaM increased serine-phosphorylated residues of the 115-kDa protein, indicating the involvement of CaMKII in the regulatory phosphorylation of SERCA2. Phosphorylation is accompanied by an 8-fold increase of thapsigargin-sensitive Ca2+ accumulation in the lumen of vesicles derived from these membranes. These data establish that SERCA2 in the RVD is modulated by Ca2+ and CaM, possibly via CaMKII, in a process that results in stimulation of Ca2+ pumping activity.

Utility of a novel risk score for prediction of ventricular tachycardia and cardiac death in chronic Chagas disease - the SEARCH-RIO study

The SEARCH-RIO study prospectively investigated electrocardiogram (ECG)-derived variables in chronic Chagas disease (CCD) as predictors of cardiac death and new onset ventricular tachycardia (VT). Cardiac arrhythmia is a major cause of death in CCD, and electrical markers may play a significant role in risk stratification. One hundred clinically stable outpatients with CCD were enrolled in this study. They initially underwent a 12-lead resting ECG, signal-averaged ECG, and 24-h ambulatory ECG. Abnormal Q-waves, filtered QRS duration, intraventricular electrical transients (IVET), 24-h standard deviation of normal RR intervals (SDNN), and VT were assessed. Echocardiograms assessed left ventricular ejection fraction. Predictors of cardiac death and new onset VT were identified in a Cox proportional hazard model. During a mean follow-up of 95.3 months, 36 patients had adverse events: 22 new onset VT (mean±SD, 18.4±4‰/year) and 20 deaths (26.4±1.8‰/year). In multivariate analysis, only Q-wave (hazard ratio, HR=6.7; P<0.001), VT (HR=5.3; P<0.001), SDNN<100 ms (HR=4.0; P=0.006), and IVET+ (HR=3.0; P=0.04) were independent predictors of the composite endpoint of cardiac death and new onset VT. A prognostic score was developed by weighting points proportional to beta coefficients and summing-up: Q-wave=2; VT=2; SDNN<100 ms=1; IVET+=1. Receiver operating characteristic curve analysis optimized the cutoff value at >1. In 10,000 bootstraps, the C-statistic of this novel score was non-inferior to a previously validated (Rassi) score (0.89±0.03 and 0.80±0.05, respectively; test for non-inferiority: P<0.001). In CCD, surface ECG-derived variables are predictors of cardiac death and new onset VT.

Caryocar brasiliense camb protects against genomic and oxidative damage in urethane-induced lung carcinogenesis

The antioxidant effects of Caryocar brasiliense Camb, commonly known as the pequi fruit, have not been evaluated to determine their protective effects against oxidative damage in lung carcinogenesis. In the present study, we evaluated the role of pequi fruit against urethane-induced DNA damage and oxidative stress in forty 8-12 week old male BALB/C mice. An in vivo comet assay was performed to assess DNA damage in lung tissues and changes in lipid peroxidation and redox cycle antioxidants were monitored for oxidative stress. Prior supplementation with pequi oil or its extract (15 µL, 60 days) significantly reduced urethane-induced oxidative stress. A protective effect against DNA damage was associated with the modulation of lipid peroxidation and low protein and gene expression of nitric oxide synthase. These findings suggest that the intake of pequi fruit might protect against in vivo genotoxicity and oxidative stress.

Single-walled carbon nanotubes functionalized with sodium hyaluronate enhance bone mineralization

The aim of this study was to evaluate the effects of sodium hyaluronate (HY), single-walled carbon nanotubes (SWCNTs) and HY-functionalized SWCNTs (HY-SWCNTs) on the behavior of primary osteoblasts, as well as to investigate the deposition of inorganic crystals on titanium surfaces coated with these biocomposites. Primary osteoblasts were obtained from the calvarial bones of male newborn Wistar rats (5 rats for each cell extraction). We assessed cell viability using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay and by double-staining with propidium iodide and Hoechst. We also assessed the formation of mineralized bone nodules by von Kossa staining, the mRNA expression of bone repair proteins, and the deposition of inorganic crystals on titanium surfaces coated with HY, SWCNTs, or HY-SWCNTs. The results showed that treatment with these biocomposites did not alter the viability of primary osteoblasts. Furthermore, deposition of mineralized bone nodules was significantly increased by cells treated with HY and HY-SWCNTs. This can be partly explained by an increase in the mRNA expression of type I and III collagen, osteocalcin, and bone morphogenetic proteins 2 and 4. Additionally, the titanium surface treated with HY-SWCNTs showed a significant increase in the deposition of inorganic crystals. Thus, our data indicate that HY, SWCNTs, and HY-SWCNTs are potentially useful for the development of new strategies for bone tissue engineering.

Composição em carboidratos de alguns cultivares de banana (Musa spp.) durante o amadurecimento

Durante o amadurecimento da banana ocorre redução dos teores de amido e acúmulo de açúcares como frutose, glicose, com predominância de sacarose, com reflexos importantes na qualidade do fruto. Essas alterações têm sido estudadas em nosso laboratório no cultivar Nanicão. O objetivo deste trabalho foi avaliar em outros cultivares as diferenças na degradação do amido e acúmulo de açúcares solúveis nos estágios pré-climatérico e climatérico do amadurecimento, visando também sua possível utilização comercial. Para tanto, os frutos foram analisados quanto ao teor de açúcares solúveis (glicose, frutose e sacarose) e de amido pelo método enzimático, após extração com etanol 80% e hidróxido de sódio, respectivamente. Os cultivares estudados apresentaram diferenças acentuadas nos teores de açúcares solúveis nos frutos maduros, variando desde 9,7% no cultivar Mysore até 20,6% na banana Nanica. Observou-se uma queda no teor de amido paralelamente ao acúmulo de açúcares solúveis. No cultivar Ouro Colatina o teor de amido variou de 22,0% no fruto verde a 1,2% no fruto maduro, havendo acúmulo de sacarose no decorrer do amadurecimento atingindo níveis de 12,0%. Nos cultivares Nanica e Nanicão os teores de amido foram de 21,7% a 0,9% e 23,1% a 0,9% com acúmulo de sacarose a 15,2% e 14,0% no fruto maduro, respectivamente.

CARACTERÍSTICAS DE QUALIDADE DO CONTRAFILÉ (m. L. dorsi) DE TOUROS JOVENS DA RAÇA NELORE

Com o objetivo de analisar as características de qualidade da carne de touros jovens da raça Nelore e os possíveis efeitos da idade, entre os 690 e os 780 dias, nessas características, efetuou-se o abate de 113 bovinos, que haviam sido confinados por um período de 109 dias com ração à base de 20% de concentrado e 80% de volumoso. Todas as carcaças foram tipificadas pela Inspeção Federal na sala de matança do frigorífico e resfriadas por 24 h em câmara fria (Tinicial=5°C; Tfinal=2°C). Meias carcaças (lado direito, N=51), do tipo B - do Sistema B R A S I L - de animais de 23 a 26 meses foram desossadas. Dois bifes (2,5cm de espessura) de contrafilé (m. L. dorsi) de cada uma foram embalados à vácuo e maturados por 7 dias a 0-2°C. O pH variou entre 5,44 e 5,83 e apenas duas amostras tinham pHNT FACE="Symbol"> ³nt> 5,70. O valor L* (luminosidade) médio foi de 34,85. As médias de umidade e gordura foram de 75,65% e 1,71%, respectivamente. A média de força de cisalhamento foi de 6,70kg e não foi influenciada pela idade do animal entre 690 e 734 dias, mas apresentou uma tendência (Teste t, p=0,22) de aumento entre 735 e 780 dias. Não se detectou influência da idade do animal nas demais características de qualidade analisadas (Teste t, p>0,20). Concluiu-se que o contrafilé de animais como esses pode ter problemas de aceitação na faixa mais exigente de mercado, e que carcaças tipificadas como B, presumivelmente o melhor tipo, não apresentam necessariamente as melhores características de qualidade da carne.

Metabolismo de carboidratos durante o amadurecimento do mamão (Carica papaya L. Cv. Solo): influência da radiação gama

A irradiação de alimentos é um tratamento pós-colheita bastante promissor, capaz de atuar tanto na desinfestação como no aumento da vida útil de frutos. O mamão é um fruto com curta vida pós-colheita, levando de 6 a 12 dias para atingir a senescência. Além disto, a infestação por larvas de mosca diminui sensivelmente o seu potencial de exportação. O objetivo deste trabalho foi verificar a ação de uma dose de 0,5 kGy de irradiação gama, normalmente utilizada para desinfestação e aumento de vida útil dos frutos, sobre o comportamento dos carboidratos solúveis durante o amadurecimento do mamão (Carica papaya L. cv. Solo), e sobre as enzimas relacionadas ao metabolismo da sacarose: sacarose sintase (SS), sacarose-fosfato sintase (SPS) e invertases ácida e neutra. Os resultados demonstraram que a irradiação não exerce efeito sobre o teor de glicose e frutose, ou sobre a respiração e atividade da SS. Entretanto, a composição dos açúcares solúveis totais e da sacarose, e a atividade da SPS e das invertases foram afetados.

On the formulation and the calculation of the harmonic contributions to the Debye-Waller factor in metals (sodium)

The algebraic expressions for the anharmonic contributions to the Debye-Waller factor up to 0(A ) and 0 L% ) £ where ^ is the scattering wave-vector] have been derived in a form suitable for cubic metals with small ion cores where the interatomic potential extends to many neighbours. This has been achieved in terms of various wave-vector dependent tensors, following the work of Shukla and Taylor (1974) on the cubic anharmonic Helmholtz free energy. The contribution to the various wave-vector dependent tensors from the coulomb and the electron-ion terms in the interatomic metallic potential has been obtained by the Ewald procedure. All the restricted multiple whole B r i l l o u i n zone (B.Z.) sums are reduced to single whole B.Z. sums by using the plane wave representation of the delta function. These single whole B.Z. sums are further reduced to the •%?? portion of the B.Z. following Shukla and Wilk (1974) and Shukla and Taylor (1974). Numerical calculations have been performed for sodium where the Born-Mayer term in the interatomic potential has been neglected because i t is small £ Vosko (1964)3 • *n o^er to compare our calculated results with the experimental results of Dawton (1937), we have also calculated the r a t io of the intensities at different temperatures for the lowest five reflections (110), (200), (220), (310) and (400) . Our calculated quasi-harmonic results agree reasonably well with the experimental results at temperatures (T) of the order of the Debye temperature ( 0 ). For T » © ^ 9 our calculated anharmonic results are found to be in good agreement with the experimental results.The anomalous terms in the Debye-Waller factor are found not to be negligible for certain reflections even for T ^ ©^ . At temperature T yy Op 9 where the temperature is of the order of the melting temperature (Xm) » "the anomalous terms are found to be important almost for all the f i ve reflections.

Stabilité temporelle du Thermomètre de détresse et de l'Échelle d'évaluation des symptômes d'Edmonton-révisée chez des parents de survivants d'une tumeur pédiatrique

Essai doctoral présenté à la Faculté des arts et des sciences en vue de l’obtention du grade de Docteur en psychologie, option psychologie clinique (D.Psy.)

On Szegö’s Type Theorems

This study is to look the effect of change in the ordering of the Fourier system on Szegö’s classical observations of asymptotic distribution of eigenvalues of finite Toeplitz forms.This is done by checking proofs and Szegö’s properties in the new set up.The Fourier system is unconditional [19], any arbitrary ordering of the Fourier system forms a basis for the Hilbert space L2 [-Π, Π].Here study about the classical Szegö’s theorem.Szegö’s type theorem for operators in L2(R+) and check its validity for certain multiplication operators.Since the trigonometric basis is not available in L2(R+) or in L2(R) .This study discussed about the classes of orderings of Haar System in L2 (R+) and in L2(R) in which Szegö’s Type TheoreT Am is valid for certain multiplication operators.It is divided into two sections. In the first section there is an ordering to Haar system in L2(R+) and prove that with respect to this ordering, Szegö’s Type theorem holds for general class of multiplication operators Tƒ with multiplier ƒ ε L2(R+), subject to some conditions on ƒ.Finally in second section more general classes of ordering of Haar system in L2(R+) and in L2(R) are identified in such a way that for certain classes of multiplication operators the asymptotic distribution of eigenvalues exists.

Studies on the Biology, Ecology and Fishery of the sea cucumber Holathuria (hetriatyla) scabra (Jaeger) from southeast coast of India

The distribution of the holothurian H. KH.) scabra indicated its availability all along coastal areas on Palk Bay from Rameswavam to Mallipattinam and along the Gulf of Hannah coast from Pamban to Ervadi and Tuticmhin,'at 4~2O m depth.The major fishing for holmthurians was done by skin diving at all the centres. The tallu valai was operated at Tuticorin and Vedalai and trawlevs were operated at Rameswaram.The fmod of H. KN.) scabra consists of ovganic matter which contains mud, sand, shell debris, bivalves and algae. Obsehvatinns indicated the species seems to be a n0n—se1ective feeder. The assimilation efficiency from sediment to faeces indicated that the faecal pellets of H. KH.) scabra are semidigested.A multiple relationship was fitted between total length, total weight, gutted weight, gonad weight and maturity stages were found significant.The fishing season for holothurians commences from October to March along Gulf of Manner coast and from March to October along Palk Bay coast.The percentage of catches recorded by skin diving, trawlere and tallu valai were 80.04%, 10.27% and 9.69% respectively. Skin diving contributes to maximum catch.The holothurians landed all along the Gulf of Manner and Palk Bay coasts constitute 25.6% and 74.4% respectively. This showed that Palk Bay coast is more productive.

Studies on osmoregulation in the penaeid prawn Metapenaeus dobsoni (Miers)

Metapenaeus dobsoni (Miers) is the most abundant species along the coast of Kerala. It is cultured extensively by adoption of traditional farming practices. The geographical location and water source determines the seasonal and annual environmental fluctuations the prawn farming systems experiences. The life cycle of the shrimp includes its migration to the coastal deeper waters for spawning and the immigration of larvae to the estuaries for growth. The survival of the species in such complex ecosystems is thus critical to its life cycle. The animal adapts itself to different environments through a physiological process known as osmoregulation. The present study on osmoregulation in the penaeid prawn Metapenaeus dobsoni was thus undertaken to understand the mechanism adopted by this species to survive in different environments. A number of experimental work have been conducted to understand the effect of salinity on the internal variations. However the effect of the complex environmental conditions as existent in nature on the osmotic variations in this species has not been dealt with in any of the earlier studies.

Studies on the reproductive physiology of lazes calcarifer (BLOCH)

At present, there is paucity of information regarding the breeding biology, especially from southeastern region, which differs in its climatic features from northeastern coastal areas, where some attempts have been made to study the biology of the fish, though not documented in detail (Jhingran and Natarajan, I969; Patnaik and Jena, 1976; Kowtal, 1977; Roy e_t _a_l_., I977). The present work, first to undertake detailed investigation into reproductive aspects of the fish from India is not only confined to biology, but extend to the study on histological as well as physiological changes in the processes associated with natural reproductive cycle. The main objective of the study is to develop a background for the standardisation of subsequent artificial propagation techniques for the Sea Dass The thesis is presented in three chapters. The first chapter; general introduction, surveys the literature pertaining to the status of research on Lates calcarifer with specific reference to reproduction and acquaculture. The second chapter entitled, materials and methods gives description regarding collection of specimens as well as samples in addition to the various analytical methodologies employed during the study.

Studies on tuna livebait fishes of Lakshadweep

Extensive investigations on the distribution and biology of skipjack tuna are available but less is known of the bait fishes on which this fishery depends and what is known is inadequate, fragmentary and of cursory nature. The information available on tuna livebait fishes of Lakshadweep are mainly cofined to short term surverys aimed at estimating theiravailability and abundance. Reports on the biology of a few species from Minicoy are also present in the literature. This study was, therefore, prompted by a paucity of information on 1) the livebits of Minicoy, 2) livebait fishery of the northern islands and 3) knowledge of livebait ecology