RING finger-dependent ubiquitination by PRAJA is dependent on TGF-beta and potentially defines the functional status of the tumor suppressor ELF

In gastrointestinal cells, biological signals for transforming growth factor-beta (TGF-beta) are transduced through transmembrane serine/threonine kinase receptors that signal to Smad proteins. Smad4, a tumor suppressor, is often mutated in human gastrointestinal cancers. The mechanism of Smad4 inactivation, however, remains uncertain and could be through E3-mediated ubiquitination of Smad4/adaptor protein complexes. Disruption of ELF (embryonic liver fodrin), a Smad4 adaptor protein, modulates TGF-beta signaling. We have found that PRAJA, a RING-H2 protein, interacts with ELF in a TGF-beta-dependent manner, with a fivefold increase of PRAJA expression and a subsequent decrease in ELF and Smad4 expression, in gastrointestinal cancer cell lines (P < 0.05). Strikingly, PRAJA manifests substantial E3-dependent ubiquitination of ELF and Smad3, but not Smad4. Delta-PRAJA, which has a deleted RING finger domain at the C terminus, abolishes ubiquitination of ELF. A stable cell line that overexpresses PRAJA exhibits low levels of ELF in comparison to a Delta-PRAJA stable cell line, where ELF expression is high compared to normal controls. The alteration of ELF and/or Smad4 expression and/or function in the TGF-beta signaling pathway may be induced by enhancement of ELF degradation, which is mediated by a high-level expression of PRAJA in gastrointestinal cancers. In hepatocytes, half-life (t(1/2)) and rate constant for degradation (k(D)) of ELF is 1.91 h and 21.72 min(-1) when coupled with ectopic expression of PRAJA in cells stimulated by TGF-beta, compared to PRAJA-transfected unstimulated cells (t(1/2) = 4.33 h and k(D) = 9.6 min(-1)). These studies reveal a mechanism for tumorigenesis whereby defects in adaptor proteins for Smads, such as ELF, can undergo degradation by PRAJA, through the ubiquitin-mediated pathway.

Effect of pH on One-Electron Oxidation Chemistry of Organoselenium Compounds in Aqueous Solutions

Pulse radiolysis coupled with absorption detection has been employed to study one-electron oxidation of selenomethionine (SeM), selenocystine (SeCys), methyl selenocysteine (MeSeCys), and selenourea (SeU) in aqueous solutions. Hydroxyl radicals (*OH) in the pH range from 1 to 7 and specific one-electron oxidants Cl2*- (pH 1) and Br2*- (pH 7) have been used to carry out the oxidation reactions. The bimolecular rate constants for these reactions were reported to be in the range of 2 x 10(9) to 10 x 10(9) M(-1) s(-1). Reactions of oxidizing radicals with all these compounds produced selenium-centered radical cations. The structure and stability of the radical cation were found to depend mainly on the substituent and pH. SeM, at pH 7, produced a monomer radical cation (lambdamax approximately 380 nm), while at pH 1, a dimer radical cation was formed by the interaction between oxidized and parent SeM (lambdamax approximately 480 nm). Similarly, SeCys, at pH 7, on one-electron oxidation, produced a monomer radical cation (lambdamax approximately 460 nm), while at pH 1, the reaction produced a transient species with (lambdamax approximately 560 nm), which is also a monomer radical cation. MeSeCys on one-electron oxidation in the pH range from 1 to 7 produced monomer radical cations (lambdamax approximately 350 nm), while at pH < 0, the reaction produced dimer radical cations (lambdamax approximately 460 nm). SeU at all the pH ranges produced dimer radical cations (lambdamax approximately 410 nm). The association constants of the dimer radical cations of SeM, MeSeCys, and SeU were determined by following absorption changes at lambdamax as a function of concentration. From these studies it is concluded that formation of monomer and dimer radical cations mainly depends on the substitution, pH, and the heteroatoms like N and O. The availability of a lone pair on an N or O atom at the beta or gamma position results in monomer radical cations having intramolecular stabilization. When such a lone pair is not available, the monomer radical cation is converted into a dimer radical cation which acquires intermolecular stabilization by the other selenium atom. The pH dependency confirms the role of protonation on stabilization. The oxidation chemistry of these selenium compounds is compared with that of their sulfur analogues.

An outbreak of dengue fever in periurban slums of Chandigarh, India, with special reference to entomological and climatic factors

BACKGROUND

Dengue viral infection is one of the most important public health problem in tropical countries.

AIM

An outbreak of dengue fever was investigated in a periurban slum area of Chandigarh, India, during September to December, 2002.

MATERIALS AND METHODS

Blood samples from 218 patients and 30 apparently healthy contacts were tested for dengue-specific immunoglobulin M (IgM) and IgG antibodies including 80 acute samples collected within 5 days of illness were subjected for virus isolation in newborn mice. The average temperature, rainfall, and humidity of the epidemic year were compared with the number of dengue cases.

STATISTICAL ANALYSIS

statistical significance was found out using c2-test.

RESULTS

A total of 76 cases were positive by either dengue IgM capture assay (n = 57) or virus isolation (n = 17) or both (n = 2). Fifteen of nineteen viral isolates subjected for typing by type-specific multiplex reverse transcription-polymerase chain reaction were found to be of dengue virus. High rainfall and humidity with the temperature range from 21 degrees C to 33 degrees C during the months of August and September might have favored the breeding of mosquitoes, thus leading to an increase in the number of dengue cases in October and November, 2002.

CONCLUSION

The present outbreak thus emphasizes the need for continuous sero epidemiological and entomological surveillance for the timely implementation of effective dengue control programme.

Changing trend of SSPE over a period of ten years

Sub acute sclerosing pan-encephalitis (SSPE) is a slowly progressive inflammatory disorder of the central nervous system. A decline in frequency has been noticed in most of the developed countries, whereas it continues to be high in developing countries. Though a number of studies have been carried out, the exact trend of SSPE is still not clear. Hence the present study was carried out to analyze the trend of SSPE over the past ten years in and around Chandigarh. A total of 205 patients with clinical features suggestive of SSPE were enrolled for the study during Jan'92 to Dec. 2001. Measles specific antibodies were detected in blood and CSF by HAI method. 114 patients were found to be positive for measles specific HAI antibody with a male preponderance. The number of SSPE cases were found to be more during the period 1992-95 in comparison to the next 6 years (p < 0.05). The high incidence of SSPE in our country could be due to improper vaccine coverage, poor cold chain maintenance or circulation of atypical measles virus strain.

Viral infections in sudden hearing loss. Do we have enough evidence?

OBJECTIVE

The aetiology of sudden deafness remains unknown even though some evidences suggest that it could be viral in origin. This study aimed to find out the relationship between viral infections and sudden sensorineural hearing loss.

METHODS

32 patients presenting with sudden deafness and 10 healthy controls were included in the study. IgM antibodies to varicella zoster virus, measles, cytomegalovirus and herpes simplex virus were detected using micro ELISA.

RESULTS

Overall, 7(21.8%) patients showed seropositivity to one or more viruses. Virus specific IgM antibodies against measles and varicella zoster could be demonstrated in 4 (12.5%) and 3 (9.4%) patients respectively. None of the samples were found to be positive for herpes simplex virus (HSV) and human cytomegalovirus (HCMV) specific IgM antibodies. Controls were negative for all the viruses tested. The difference in seropositivity between the patient and control group was not statistically significant (p>0.05).

CONCLUSION

Thus, this study suggests that sudden deafness is not commonly associated with a systemic viral infection.

Reactions of Biological Oxidants with Selenourea: Formation of Redox Active Nanoselenium

Reactions of biological oxidizing agents, such as hydroxyl radicals ((*)OH), singlet oxygen ((1)O(2)), hydrogen peroxide (H(2)O(2)), and peroxynitrite (ONOO(-)) with selenourea were studied. The kinetics of the reactions was followed using time-resolved techniques, and the bimolecular rate constants were determined. In all these reactions, under aerated conditions, elemental red selenium was produced as one of the reaction products. The average size of the selenium particles could be controlled and stabilized in the range of 20-100 nm with the addition of bovine serum albumin (BSA) or sodium dodecyl sulfate (SDS). The particles were characterized by dynamic light scattering studies (DLS), which revealed that the size and distribution of the particles depended mainly on the amount of selenourea undergoing oxidation. Other factors such as the nature of the oxidant and the concentration of the stabilizer also are important in stabilizing the particles. Nanoselenium-reduced ABTS(*-) to colorless ABTS(2-) (ABTS = 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) and oxidized dichlorodihydrofluoresecein diacetate (DCFA) to fluorescent dichlorofluorescein (DCF) indicating its ability to participate in redox and free radical reactions. The reactivity of selenium nanoparticles with these systems varied linearly with the surface area of the particles. The studies demonstrate that selenourea undergoes oxidation with both one-electron and two-electron oxidants to produce elemental selenium, which, on stabilization to nanometer size, exhibits size-dependent redox activity.

Fast and cheap genome wide haplotype construction via optical mapping

We describe an efficient algorithm to construct genome wide haplotype restriction maps of an individual by aligning single molecule DNA fragments collected with Optical Mapping technology. Using this algorithm and small amount of genomic material, we can construct the parental haplotypes for each diploid chromosome for any individual. Since such haplotype maps reveal the polymorphisms due to single nucleotide differences (SNPs) and small insertions and deletions (RFLPs), they are useful in association studies, studies involving genomic instabilities in cancer, and genetics, and yet incur relatively low cost and provide high throughput. If the underlying problem is formulated as a combinatorial optimization problem, it can be shown to be NP-complete (a special case of K-population problem). But by effectively exploiting the structure of the underlying error processes and using a novel analog of the Baum-Welch algorithm for HMM models, we devise a probabilistic algorithm with a time complexity that is linear in the number of markers for an epsilon-approximate solution. The algorithms were tested by constructing the first genome wide haplotype restriction map of the microbe T. pseudoana, as well as constructing a haplotype restriction map of a 120 Mb region of Human chromosome 4. The frequency of false positives and false negatives was estimated using simulated data. The empirical results were found very promising.

In vitro antioxidant studies and free radical reactions of triphala, an ayurvedic formulation and its constituents

The aqueous extract of the fruits of Emblica officinalis (T1), Terminalia chebula (T2) and Terminalia belerica (T3) and their equiproportional mixture triphala were evaluated for their in vitro antioxidant activity. gamma-Radiation induced strand break formation in plasmid DNA (pBR322) was effectively inhibited by triphala and its constituents in the concentration range 25-200 microg/mL with a percentage inhibition of T1 (30%-83%), T2 (21%-71%), T3 (8%-58%) and triphala (17%-63%). They also inhibited radiation induced lipid peroxidation in rat liver microsomes effectively with IC(50) values less than 15 microg/mL. The extracts were found to possess the ability to scavenge free radicals such as DPPH and superoxide. As the phenolic compounds present in these extracts are mostly responsible for their radical scavenging activity, the total phenolic contents present in these extracts were determined and expressed in terms of gallic acid equivalents and were found to vary from 33% to 44%. These studies revealed that all three constituents of triphala are active and they exhibit slightly different activities under different conditions. T1 shows greater efficiency in lipid peroxidation and plasmid DNA assay, while T2 has greater radical scavenging activity. Thus their mixture, triphala, is expected to be more efficient due to the combined activity of the individual components.

Identification of flanking SSR markers for a major rice gall midge resistance gene Gm1 and their validation

Host-plant resistance is the preferred strategy for management of Asian rice gall midge (Orseolia oryzae), a serious pest in many rice-growing countries. The deployment of molecular markers linked to gall midge resistance genes in breeding programmes can accelerate the development of resistant cultivars. In the present study, we have tagged and mapped a dominant gall midge resistance gene, Gm1, from the Oryza sativa cv. W1263 on chromosome 9, using SSR markers. A progeny-tested F2 mapping population derived from the cross W1263/TN1 was used for analysis. To map the gene locus, initially a subset of the F2 mapping population consisting of 20 homozygous resistant and susceptible lines each was screened with 63 parental polymorphic SSR markers. The SSR markers RM316, RM444 and RM219, located on chromosome 9, are linked to Gm1 at genetic distances of 8.0, 4.9 and 5.9 cM, respectively, and flank the gene locus. Further, gene/marker order was also determined. The utility of the co-segregating SSR markers was tested in a backcross population derived from the cross Swarna/W1263//Swarna, and allelic profiles of these markers were analysed in a set of donor rice genotypes possessing Gm1 and in a few gall midge-susceptible, elite rice varieties.

Indirect immunofluorescence test: role in seroepidemiology and serodiagnosis of herpes simplex viral infections

A study was carried out to find out a) the seroprevalence of herpes simplex viral infections (HSV) in and around Chandigarh city, North India and the probable age of acquisition of infection; b) the usefulness of salivary antibody detection in seroprevalence studies; c) role of HSV immunofluorescence antibodies in the sero-diagnosis of herpes simplex encephalitis (HSE) patients. Single blood samples from 306 and paired blood and saliva samples from 48 apparently healthy individuals as well as paired blood and C.S.F. samples from 50 clinically suspected patients of HSE were included in the study proper. The subjects belonged to <6 months to > 30 years age group. Serum, saliva and C.S.F. samples were subjected to in house standardized indirect immunofluorescence test for the detection of HSV antibody. The overall seropositivity was 59.3%, which increased from 37.5% in children less than 10-years of age to 88.9% in individuals above 30 years of age (p<0.001). The maximum titer in less than 10 years children and above 10 years subjects were found to be 40 and 160 respectively. The difference in percentage positivity of HSV antibody in these groups was statistically significant (p<0.001). No difference in the seroprevalence rate was observed between different socio-economic groups and sex. Saliva in comparison to serum showed a sensitivity of 44% and specificity of 100% for the detection of HSV antibodies. Among the suspected HSE patients 4 (8%) could be serologically confirmed. This study indicated the endemicity of HSV infection in this locality. Indirect immunofluorescence test could detect intrathecal HSV antibodies in 8% of suspected HSE patients proving it to be a very useful rapid serodiagnostic tool. However, saliva testing showed limited sensitivity in HSV sero surveys.

Foundations of a query and simulation system for the modeling of biochemical and biological processes

The analysis of large amounts of data, produced as (numerical) traces of in vivo, in vitro and in silico experiments, has become a central activity for many biologists and biochemists. Recent advances in the mathematical modeling and computation of biochemical systems have moreover increased the prominence of in silico experiments; such experiments typically involve the simulation of sets of Differential Algebraic Equations (DAE), e.g., Generalized Mass Action systems (GMA) and S-systems. In this paper we reason about the necessary theoretical and pragmatic foundations for a query and simulation system capable of analyzing large amounts of such trace data. To this end, we propose to combine in a novel way several well-known tools from numerical analysis (approximation theory), temporal logic and verification, and visualization. The result is a preliminary prototype system: simpathica/xssys. When dealing with simulation data simpathica/xssys exploits the special structure of the underlying DAE, and reduces the search space in an efficient way so as to facilitate any queries about the traces. The proposed system is designed to give the user possibility to systematically analyze and simultaneously query different possible timed evolutions of the modeled system.

A hospital based study of hepatitis E by serology

Hepatitis E virus is recently recognised as an important cause of non-A, non-B hepatitis. A total of 569 serum samples were screened for HEV between April 1997 and March 2000, by a commercially available HEV IgM capture ELISA. The diagnosis was invariably acute viral hepatitis for differential diagnosis of jaundice. The percentage of seropositivity was found to be 18.8% in confirmed Hepatitis E cases.

Primary splenic flexure volvulus--a case report with review of literature

Splenic flexure is a rare site for volvulus. Very few cases have been reported in the literature. Cases mostly present with recurrent attacks of obstruction with distension of the abdomen. A case of a young female who had primary splenic plexure volvulus due to absence of ligamental attachment has been presented here. Resection of the volvulus segment with end to end anastomosis is the curative surgical treatment.