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K B Singh

Publications and source records attributed to K B Singh.

At least 19 recordsLinked to original sources
PubMed2005

Differential expression of inducible nitric oxide synthase and cytokine mRNA in chicken lines divergent for cutaneous hypersensitivity response.

Phytohemagglutinin (PHA)-induced delayed-type hypersensitivity is an immunocompetent trait considered an indicator of cell-mediated immune or T-cell responses. Divergent selection was performed to generate high and low lines for response to PHA-P. Extreme-responder birds of the F2 generation in each line were used to study possible differences in macrophage activity and the associated functional genes. To evaluate macrophage activity, nitric oxide (NO) was estimated both systemically in serum and in in vitro monocyte culture. Semi-quantitative RT-PCR was used to detect the differential mRNA expression patterns of iNOS and MIP-1beta in monocyte culture, whereas T(H)1 cytokines (IL-2 and IFN-gamma) were studied in peripheral blood mononuclear cells (PBMC) at different time intervals after lipopolysaccharide (LPS) induction. The high line showed strong systemic, as well as in vitro NO production, compared to the low line, upon stimulation with NDV and LPS, similar to early and high iNOS mRNA expression. Following the pattern of iNOS gene expression, an early strong expression of cytokines with powerful iNOS-inducing action, such as IFN-gamma and the chemokine MIP-1beta, was observed in the high line. In contrast, for response to PHA-P, low expression of IL-2 was observed in the high compared to the low line. In conclusion, the study revealed that divergent selection for response to PHA-P resulted in a divergent effect on T(H)1 cell activity, resulting in altered macrophage function in chickens. Selection, based on response to PHA-P, could lead to more resistant birds or birds with an enhanced immune response.

Animals↗
PubMed2001

Estimation of mortality and morbidity due to strokes in India.

In order to control the stroke problem, its magnitude should be assessed. India is ranked among the countries where the information on stroke is minimal. We decided to review the information available in order to estimate the mortality and morbidity due to stroke in India. Information was collected through electronic search, hand search and contact with experts. Each article was reviewed for relevance and epidemiological rigor. The demographic data were as derived from published government figures. The prevalence from individual studies was pooled and weighted based on sample size. Analysis was done separately for males and females at 10-year intervals (20 years onwards). A total of 7 studies was located, but 2 were discarded. All were done in rural areas except 2 which also included urban areas. The prevalence was estimated as 203 per 100,000 population above 20 years amounting to a total of about 1 million cases. The male to female ratio was 1.7. Around 12% of all strokes occurred in population below 40 years. The estimation of stroke mortality was seriously limited by the method of classification of cause of death in the country. The best estimate derived was 102,000 deaths; which represented 1.2% of total deaths in the country. There is need to initiate steps to collect data on morbidity and mortality due to stroke in the country as a first step towards control measures.

Adolescent↗
PubMed2000

Characterization of salicylic acid-responsive, arabidopsis Dof domain proteins: overexpression of OBP3 leads to growth defects.

Dof proteins are unique to plants and contain a single zinc finger DNA-binding domain called the Dof domain. OBP1, an Arabidopsis Dof protein, was previously isolated through an interaction with OBF4, an ocs element-binding protein. Two additional Dof proteins, called OBP2 and OBP3, were isolated through homologous screening. All three OBP proteins contain transcriptional activation domains in their C-terminal region. While no significant differences were found between the OBP proteins in terms of their DNA and protein-binding properties, tissue-specific RNA expression patterns were found. The RNA expression levels of all three OBP proteins increased following treatment with auxin, salicylic acid (SA) or cycloheximide, although the level of induction varied among the different proteins and in the tissues tested. These results suggest that even though they have similar DNA binding and protein-protein interaction properties, the different OBP proteins are likely to have distinct functions in specific parts of the plant. There is a good correlation between the expression of the OBP proteins and the ocs element, a stress-response element which is also induced by auxin, SA and cycloheximide. To begin to analyze the function of the OBP proteins, transgenic lines overexpressing OBP3 were generated. These plants showed a severe growth defect with altered root development and yellowish leaves. The severity of the growth defects correlated with OBP3 expression levels and in some cases led to death, suggesting that some Dof proteins play important roles in plant growth and development.

Amino Acid Sequence↗
PubMed1999

The auxin, hydrogen peroxide and salicylic acid induced expression of the Arabidopsis GST6 promoter is mediated in part by an ocs element.

Glutathione S-transferases (GSTs) are multi-functional enzymes that play critical roles in a number of plant stress responses. Ocs elements are enhancer sequences found in some pathogen and GST promoters. We previously isolated an Arabidopsis GST gene, called GST6, which contained an ocs-like element. Here we tested the role this putative ocs element plays in GST6 expression in response to auxin, salicylic acid (SA) and hydrogen peroxide (H2O2) using a transient assay and transgenic Arabidopsis. The requirement for the ocs element for basal and/or induced expression varied between the transient and transgenic studies, and in different plant tissues. The GST6 promoter showed the largest induction in roots following treatment with SA (84-fold) or H2O2 (122-fold), and the effect of mutating the ocs element was most pronounced in root tissue. However, in no case did mutation of the ocs element abolish GST6 expression, suggesting that other promoter element(s) are also important. Using the transient assay, other promoter element(s) critical for GST6 expression were identified that may also help mediate the activity of the ocs element. The finding that the ocs element plays a role in the transcriptional response of a plant GST gene to SA and H2O2 has potential significance for the plant defense response, where SA and H2O2 play critical roles.

Arabidopsis↗
PubMed1999

A glucocorticoid-inducible transcription system causes severe growth defects in Arabidopsis and induces defense-related genes.

A glucocorticoid-inducible transcription system was employed to control the expression of AtEBP, an Arabidopsis transcription factor. A number of the transgenic AtEBP lines had developmental and growth defects when grown on dexamethasone (DEX), a strong synthetic glucocorticoid. However, these growth defects were not confined to the AtEBP lines but were observed with other transgenic lines that were generated using the same system, including empty vector lines. In about 25% of the AtEBP or empty vector transgenic lines, these growth defects were severe and in some cases led to death. As AtEBP has been linked to the plant defense response, the expression of specific defense-related genes, including a number of pathogenesis-related (PR) genes was also examined. PDF1.2, a plant defensin gene, was strongly induced in all transgenic lines examined following treatment with DEX, including empty vector lines that did not show any observable DEX-induced growth defect. PR-5 was induced to a lesser extent in all the lines, while the expression of PR-1, PR-2 and phenylalanine ammonia-lyase 3 (PAL3) did not change significantly. While the induction of the AtEBP transgene and PDF1.2 had similar DEX concentration requirements, the kinetics of induction differed significantly, with the AtEBP transgene being induced within 1 h and PDF1.2 only being induced between 24 and 48 h. Although the molecular mechanisms underlying the growth defects and changes in gene expression remain to be determined, these changes appear to result from the glucocorticoid-inducible system itself, and may therefore limit the usefulness of this system for controlling gene expression in Arabidopsis.

Arabidopsis↗
PubMed1998

Comparative ABR profile in high risk infants.

Auditory brainstem responses (ABR) were studied in 52 children upto the age of 3 months, suffering from neonatal jaundice, prematurity, pyogenic meningitis and septicemia. Absolute latency of wave I and interpeak latency I-V were found to be significantly delayed in cases of jaundice and absolute latency of wave V and interpeak latency I-V were prolonged in cases with prematurity. In cases following pyogenic meningitis absolute latency of wave V and interpeak latency of I-III, I-V were significantly delayed compared to septicemia where absolute latency I, V and interpeak latency I-V were significantly delayed (P < 0.05). Maximum auditory insult was seen in cases with neonatal jaundice where 30.77% each had severe SN deafness and 30.77% had moderate degree of deafness compared to prematurity, meningitis and septicemia where 14.28, 7.69 and 25% were found to have severe SN deafness and 7.14, 38.46 and 25% had moderate deafness. Overall incidence of deafness of any kind in these factors was 44.23%.

Brain Stem↗
PubMed1997

Arabidopsis thaliana ethylene-responsive element binding protein (AtEBP), an ethylene-inducible, GCC box DNA-binding protein interacts with an ocs element binding protein.

Ocs elements are a group of promoter sequences required for the expression of both pathogen genes in infected plants and plant defense genes. Genes for ocs element binding factors (OBFs), belonging to a specific class of basic-region leucine zipper (bZIP) transcription factors, have been isolated in a number of plants. Using protein-protein interaction screening with OBF4 we have isolated AtEBP, an Arabidopsis protein that contains a novel DNA-binding domain, the AP2/EREBP domain. One class of proteins that contain this domain are the tobacco ethylene-responsive element binding proteins (EREBPs). The EREBPs bind the GCC box that confers ethylene responsiveness to a number of pathogenesis related (PR) gene promoters. AtEBP expression is inducible by exogenous ethylene in wild-type plants and AtEBP transcripts are increased in the ctr1-1 mutant, where ethylene-regulated pathways are constitutively active. Electrophoretic mobility-shift assay and DNase I footprint analysis revealed that AtEBP can specifically bind to the GCC box. Interestingly, the highest level of AtEBP expression was detected in callus tissue, where ocs elements are very active. Synergistic effects of the GCC box with ocs elements or the related G-box sequence have been previously observed, for example, in the ethylene-induced expression of a PR gene promoter. Our results suggest that cross-coupling between EREBP and bZIP transcription factors occurs and may therefore be important in regulating gene expression during the plant defense response.

Amino Acid Sequence↗
PubMed1997

Laryngeal malakoplakia.

We report a case of malakoplakia of the epiglottis in a 45-year-old female patient. Only three cases of laryngeal malakoplakia have been reported in the world literature, one of which was associated with tracheal malakoplakia. To our knowledge this is the first reported case of isolated malakoplakia of the epiglottis. Malakoplakia, a rare granulomatous lesion, has been seen more frequently in the urinary tract. Other organs like the genito-urinary tract, testis, epididymis, lymph nodes, middle ear, nasopharynx, tonsil and retroperitoneal tissue have been also involved though less frequently.

Epiglottis↗
PubMed1997

Analysis of type 1 metallothionein cDNAs in Vicia faba.

In animals and fungi, small cysteine-rich proteins called metallothioneins (MTs) play a role in heavy metal tolerance. MT genes have been isolated in plants, but their function remains to be elucidated. We have isolated two distinct Vicia faba MT genes that belong to the type 1 group of plant MT genes in contrast to a MT gene we previously isolated that belongs to type 2. We found similarities and differences between the V. faba MT genes. The RNA expression patterns differed and this was most pronounced in roots, which contained high MT1 but very low MT2 RNA levels. Like MT2, MT1 transcript levels were not significantly affected by treatment with Cd, Cu, Fe and Zn, at least under the experimental conditions. MT RNA levels varied in leaves and stem internodes of different developmental ages, with the highest expression in the older tissue. The levels of MT RNA correlated inversely with endogenous Cd, Cu and Fe levels within different internodes, but not with a number of other metals tested (including Zn). The three bean MTs were expressed in Escherichia coli and found to bind Cd, Cu and Zn but not to Fe. The MTs were tested to determine if they differed in their ability to bind a specific metal but no significant differences in binding were observed.

Age Factors↗
PubMed1996

Hormonal modulation of the vaginal bacterial flora in experimental polycystic ovarian disease.

Rats exposed to constant light develop polycystic ovarian (PCO) disease with persistent estrus, representing an estrogen-dominant condition. Herein, we report that fluctuations seen in the vaginal microflora in cyclic rats were not observed in PCO rats with persistent estrus. The vaginal-cervical mucosa of PCO rats showed numerous adherent bacteria by scanning electron microscopy, similar to that seen in proestrus and estrus rats, but unlike the diestrus rats in which fewer organisms adhered to the mucosa. Administration of human chorionic gonadotropin induced ovulation in PCO rats, which was associated with a significant decrease in serum estradiol, an increase in progesterone, and a significant decrease in the estradiol/progesterone ratio compared with baseline values (P < 0.01). This also resulted in an influx of leukocytes in the vagina with a significant decrease in vaginal anaerobic as well as aerobic bacterial flora. These data demonstrate that loss of cyclic ovarian activity in PCO rats with persistent estrus causes increased bacterial colonization of the vaginal-cervical mucosa, and the ovarian hormones appear to modulate the colonization of bacteria in the lower genital tract.

Animals↗
PubMed1996

A novel phloem-specific gene is expressed preferentially in aerial portions of Vicia faba.

We have isolated a gene from bean (Vicia faba L.), called Vein1, that encodes a novel protein. The Vein1 cDNA was isolated as a result of a differential screen for genes that are expressed in leaves but not in the most common cell type, the mesophyll cell. Northern blot analysis revealed that Vein 1 transcripts are differentially expressed in the plant with expression in leaves, stems and sepals but not in petals, mesophyll cells or roots. In situ hybridization studies of stem and leaf sections indicate that the expression of Vein1 is localized to the phloem tissue. Interestingly, Vein1 was differentially expressed in stem tissue with the highest expression in the oldest internodes. The deduced Vein1 protein sequence does not share homology with any known protein sequences. The 17 kDa Vein1 protein is highly hydrophilic and contains a histidine-rich motif, where six out of seven amino acids are histidines. The function of Vein1 is unknown, although the expression patterns suggests that it may play a role in mature phloem tissue in the aerial parts of the plant.

Amino Acid Sequence↗
PubMed1996

The promoter of a H2O2-inducible, Arabidopsis glutathione S-transferase gene contains closely linked OBF- and OBP1-binding sites.

Glutathione S-transferases (GSTs) are a family of multifunctional enzymes that play critical roles in the detoxification of xenobiotics and the protection of tissues against oxidative damage. GSTs are important enzymes in plant responses to a number of environmental stresses including herbicides and pathogen attack. Ocs elements are a group of related, 20 bp promoter elements which have been exploited by some plant pathogens to express genes in plants. Ocs elements have also been found to regulate the expression of a plant GST promoter. An Arabidopsis GST gene, called GST6 has been isolated. GST6 expression is under tissue-specific control and is induced following treatment with auxin, salicylic acid and H2O2. The GST6 promoter contains a binding site for two Arabidopsis ocs element binding factors (OBF), that has some sequence homology to ocs element sequences. Interestingly, OBP1 (OBF binding protein), a DNA-binding protein that was isolated by screening an Arabidopsis cDNA library with a labeled OBF protein as a probe, binds next to the OBF-binding site on the GST6 promoter. OBP1 was able to significantly stimulate the binding of OBF proteins to the GST6 promoter, raising the possibility that interactions between the OBP1 and OBF proteins may be important for GST6 expression.

Amino Acid Sequence↗
PubMed1996

Laparoscopic tubal sterilization in obese women: experience from a teaching institution.

To determine whether laparoscopy presents any significant risks for tubal sterilization in obese women, we retrospectively reviewed the records of 248 consecutive patients who had laparoscopic tubal sterilization between January and December 1991 at our institution. The 147 obese women were compared with the 101 nonobese women as controls for the study parameters. Two methods of closed laparoscopy were used as interval procedures, with similar proportions in obese and nonobese women. We observed no complications in any patient, and there were not significant differences in the mean operating time and estimated blood loss between the two groups of women. We concluded that laparoscopy should be considered safe and laparoscopic tubal sterilization can be performed in obese women with the same efficiency, morbidity rate, and length of hospitalization as in nonobese women.

Adult↗
PubMed1995

Interactions between distinct types of DNA binding proteins enhance binding to ocs element promoter sequences.

Octopine synthase (ocs) elements are a group of promoter elements that have been exploited by plant pathogens to express genes in plants. ocs elements are components of the promoters of certain plant glutathione S-transferase genes and may function as oxidative stress response elements. Genes for ocs element binding factors (OBFs), which belong to a specific class of highly conserved, plant basic domain-leucine zipper transcription factors, have been isolated and include the Arabidopsis OBF4 and OBF5 genes. To characterize proteins that modulate the activity of the OBF proteins, we screened an Arabidopsis cDNA library with the labeled OBF4 protein and isolated OBP1 (for OBF binding protein). OBP1 contains a 51-amino acid domain that is highly conserved with two plant DNA binding proteins, which we refer to as the MOA domain. OBP1 is also a DNA binding protein and binds to the cauliflower mosaic virus 35S promoter at a site distinct from the ocs element in the 35S promoter. OBP1 specifically increased the binding of the OBF proteins to ocs element sequences, raising the possibility that interactions between these proteins are important for the activity of the 35S promoter.

Amino Acid Oxidoreductases↗
PubMed1994

ocs element promoter sequences are activated by auxin and salicylic acid in Arabidopsis.

ocs elements are a group of promoter elements that have been exploited by two distinct groups of plant pathogens, Agrobacterium and certain viruses, to express genes in plants. We examined the activity of single and multiple ocs elements linked to a minimal plant promoter and the uidA reporter gene in transgenic Arabidopsis. beta-Glucuronidase activity was detected only in root tips and in callus tissue after auxin treatment. A more sensitive assay revealed that auxin treatment also increased ocs element activity in aerial parts of the plant, although the absolute levels of ocs element activity were greater in roots. The response of ocs elements to exogenous auxin began within 1 h. Salicylic acid, a disease-resistance signal in plants, also increased ocs element activity in both roots and aerial parts of the plant. The question of whether the induction in ocs element activity is mediated through auxin and/or salicylic acid signal transduction pathways or is part of a more general stress response is discussed.

Arabidopsis↗