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R J Jariwalla

Publications and source records attributed to R J Jariwalla.

At least 19 recordsLinked to original sources
PubMed2001

Rice-bran products: phytonutrients with potential applications in preventive and clinical medicine.

This paper reviews phytonutrients from rice bran that have shown promising disease-preventing and health-related benefits in experimental research studies. Candidate products studied and under investigation include: inositol and related compounds, inositol hexaphosphate (IP6 or phytate), rice oil, ferulic acid, gamma-oryzanol, plant sterols, tocotrienols and RICEO, a new rice-bran-derived product. Diseases in which preventive and/or nutraceutical effects have been detected include: cancer, hyperlipidemia, fatty liver, hypercalciuria, kidney stones, and heart disease. In addition, rice-bran products may have potential applications as nutritional ingredients in the context of their utility in functional foods.

Animals↗
PubMed1997

NF-kappa B-independent suppression of HIV expression by ascorbic acid.

Ascorbic acid (ascorbate or vitamin C) has been shown to suppress the induction of HIV in latently infected T lymphocytic cells following stimulation with a tumor promoter (PMA) and inflammatory cytokine (TNF-alpha). To assess whether this inhibition was mediated via modulation of the cellular transcription factor, NF-kappa B, we carried out gel shift analysis on nuclear extracts prepared under different conditions of cell stimulation in the presence or absence of ascorbate, N-acetylcysteine (NAC), or zidovudine (AZT). Pretreatment of ACH-2 T cells by NAC followed by stimulation with PMA, TNF-alpha, or hydrogen peroxide (H2O2) resulted in strong suppression of NF-kappa B activation. In contrast, neither ascorbate nor AZT affected NF-kappa B activity under all three induction conditions in the ACH-2 cell line. Ascorbate and AZT also had no effect on NF-kappa B activation following TNF-alpha- or PMA-induced stimulation of U1 promonocytic cells. These results suggest that the molecular mechanism of HIV inhibition by ascorbate is not mediated via NF-kappa B inhibition, unlike that seen with other antioxidants.

Acetylcysteine↗
PubMed1994

Mechanistic aspects of ascorbate inhibition of human immunodeficiency virus.

We have investigated the molecular basis of the inhibitory effect of ascorbate (vitamin C) on human immunodeficiency virus (HIV) expression in unstimulated chronically infected and reporter cell lines. Comparison of intracellular HIV RNA and protein patterns of ascorbate-treated cells with corresponding patterns of untreated controls, did not show significant differences in the synthesis or processing of individual viral RNA and polypeptides, indicating that the inhibitory effect of ascorbate is not directed at steps of viral transcription or translation. Enzyme assays on cell extracts showed that the activity of an HIV LTR-directed reporter protein made in ascorbate-treated cells was reduced to approximately 11% relative to that of untreated control. These results, combined with previous observations on the suppression of HIV RT activity, are consistent with a mechanism of action in which ascorbate exerts a posttranslational inhibitory effect on HIV by causing impairment of enzymatic activity.

Ascorbic Acid↗
PubMed1992

Localization of the antigenic sites and intrinsic protein kinase domain within a 300 amino acid segment of the ribonucleotide reductase large subunit from herpes simplex virus type 2.

The 140-kDa ribonucleotide reductase (RR1) protein of herpes simplex virus type 2 (HSV-2) functions as the large subunit of virus-specified RR1 and exhibits an intrinsic protein kinase (PK) activity at its unique NH2-terminal region. The N-terminal half of RR1 contains the protein and DNA functions of the morphological transforming region III (mtrIII) of HSV-2. In the present study, we have expressed a number of truncated RR1 derivatives in a mammalian expression vector containing NH2-terminal RR1 gene fragments and amber mutants generated by site-specific mutagenesis. These derivatives, synthesized in transient expression assays, were used as test antigens to localize the epitopes of a panel of HSV-2 RR1-reactive monoclonal antibodies and to fine-map the PK catalytic domain. Our data show that the epitope for HSV-2-specific monoclonal antibody 6A-6 is located in a region of RR1 protein spanning aa 72-350. The epitopes for cross-reactive antibodies to HSV RR1, i.e., 48S and 51S, are formed predominantly by a stretch of amino acid residues specified by aa 350-376 of the RR1 molecule. The 6A-6 antibody utilized in conjunction with the RR1 amber mutants has allowed us to define a 278 aa domain within the NH2-terminal half of the 140-kDa RR1 (aa 72-350) that is sufficient for PK activity.

Base Sequence↗
PubMed1991

Enhanced malignant transformation induced by expression of a distinct protein domain of ribonucleotide reductase large subunit from herpes simplex virus type 2.

The 1.3-kilobase (kb) Pst I DNA fragment C (Pst I-C) of herpes simplex virus type 2 (HSV-2) morphological transforming region III (mtrIII; map unit 0.562-0.570) encodes part of the N-terminal half of the large subunit of ribonucleotide reductase (RR1; amino acid residues 71-502) and induces the neoplastic transformation of immortalized cell lines. To assess directly the role of these RR1 protein sequences in cell transformation, the Pst I-C fragment was cloned in an expression vector (p91023) containing an adenovirus-simian virus 40 promoter-enhancer to generate recombinant plasmid p9-C. Expression of a protein domain (approximately 65 kDa) was observed in p9-C-transfected COS-7 and Rat2 cells but not in those transfected with plasmid pHC-14 (Pst I-C in a promoterless vector). In Rat2 cells, p9-C induced highly transformed foci at an elevated frequency compared with that of pHC-14. Introduction of translation termination (TAG) condons within the RR1 coding sequence and within all three reading frames inactivated RR1 protein expression from p9-C and reduced its transforming activity to the level seen with the standard pHC-14 construct. Wild-type p9-C specified a protein kinase capable of autophosphorylation. Computer-assisted analysis further revealed significant similarity between regions of mtrIII-specific RR1 and amino acid patterns conserved within the proinsulin precursor family and DNA transposition proteins. These results identify a distinct domain of the HSV-2 RR1 protein involved in the induction of enhanced malignant transformation. In addition, the data indicate that the mtrIII DNA itself can induce basal-level transformation in the absence of protein expression.

Amino Acid Sequence↗
PubMed1991

Comparative study of the anti-HIV activities of ascorbate and thiol-containing reducing agents in chronically HIV-infected cells.

To elucidate the action of vitamin C on pathogenic human retroviruses, we investigated and compared the effects of noncytoxic concentrations of ascorbic acid (AA), its calcium salt (Ca-ascorbate), and two thiol-based reducing agents [glutathione (GSH) and N-acetyl-L-cysteine (NAC)] against human immunodeficiency virus (HIV)-1 replication in chronically infected T lymphocytes. Ca-ascorbate reduced extracellular HIV reverse transcriptase (RT) activity by about the same magnitude as the equivalent dose of AA. Long-term experiments showed that continuous presence of ascorbate was necessary for HIV suppression. NAC (10 mmol/L) caused less than twofold inhibition of HIV RT and conferred a synergistic effect (approximately eightfold inhibition) when tested simultaneously with AA (0.426 mmol/L). In contrast, nonesterified GSH (less than or equal to 1.838 mmol/L) had no effect on RT concentrations and did not potentiate the anti-HIV effect of AA. These results further support the potent antiviral activity of ascorbate and suggest its therapeutic value in controlling HIV infection in combination with thiols.

Acetylcysteine↗
PubMed1990

Suppression of human immunodeficiency virus replication by ascorbate in chronically and acutely infected cells.

We have studied the action of ascorbate (vitamin C) on human immunodeficiency virus type 1 (HIV-1), the etiological agent clinically associated with AIDS. We report the suppression of virus production and cell fusion in HIV-infected T-lymphocytic cell lines grown in the presence of nontoxic concentrations of ascorbate. In chronically infected cells expressing HIV at peak levels, ascorbate reduced the levels of extracellular reverse transcriptase (RT) activity (by greater than 99%) and of p24 antigen (by 90%) in the culture supernatant. Under similar conditions, no detectable inhibitory effects on cell viability, host metabolic activity, and protein synthesis were observed. In freshly infected CD4+ cells, ascorbate inhibited the formation of giant-cell syncytia (by approximately 93%). Exposure of cell-free virus to ascorbate at 37 degrees C for 1 day had no effect on its RT activity or syncytium-forming ability. Prolonged exposure of virus (37 degrees C for 4 days) in the presence of ascorbate (100-150 micrograms/ml) resulted in the drop by a factor of 3-14 in RT activity as compared to a reduction by a factor of 25-172 in extracellular RT released from chronically infected cells. These results indicate that ascorbate mediates an anti-HIV effect by diminishing viral protein production in infected cells and RT stability in extracellular virions.

Antiviral Agents↗
PubMed1989

Tumor progression mediated by two cooperating DNA segments of human cytomegalovirus.

The terminal fragments (EJ and EM) of the XbaI-E transforming segment of human cytomegalovirus can independently induce the tumorigenic conversion of immortalized cells. To study their interaction, Rat-2 cells were transfected singly or with a combination of cloned EJ and EM DNAs. Large transformed foci were induced at a 10-fold higher frequency by EJ plus EM than by either DNA fragment alone. Focus-derived lines transformed by EJ plus EM produced tumors in syngeneic rats at a much faster rate (5 to 7 days) than did cell lines transformed by EJ or EM alone (25 to 35 days). Southern hybridizations showed that EM-homologous DNA was retained, exhibiting a complex pattern of multiple and amplified bands in EJ-plus-EM lines compared to a simple pattern in EM-induced lines. EJ DNA was not detected in the single or double transformants. The levels of p29, a 29-kilodalton transformation-sensitive marker in Rat-2 cells, were decreased 10- to 100-fold in cell lines transformed by EJ or EM fragment alone. Synthesis of p29 was shut off in EJ- plus-EM transformants. These data demonstrate that two unlinked transforming regions of human cytomegalovirus can cooperate to produce an aggressive tumorigenic phenotype.

Animals↗
PubMed1988

Localization and DNA sequence analysis of the transforming domain (mtrII) of human cytomegalovirus.

To define the morphological transforming region II (mtrII) of human cytomegalovirus (HCMV), a series of subclones of the Xba I/BamHI fragment EM was constructed in vitro and tested for focus-forming activity and tumorigenicity. A 980-base-pair subclone of fragment EM was identified, and its nucleotide sequence revealed three small open reading frames (ORFs), encoding 79, 83, and 34 amino acid residues. S1 nuclease analysis of HCMV-infected cells identified several distinct early RNA species within mtrII, two of which (P1 and P2) were of particular interest, since the length of the protected DNA fragments would position the 5' end of the RNAs upstream of the open reading frames. In addition, the 980-base-pair transforming sequence revealed DNA elements capable of forming stem-loop structures. Thus the transforming mtrII domain of HCMV strain Towne contains both small open reading frames that are expressed in lytically infected cells and sequences resembling insertion-like structures that may be involved in transformation.

Animals↗
PubMed1988

Down-regulation of an abundant cellular protein associated with tumor progression.

Alteration of gene expression in neoplastic cells can be detected by two-dimensional gel electrophoresis. This study reports the altered synthesis of an abundant cellular protein, p29, accompanying tumorigenic transformation of immortalized fibroblasts induced by transfection with oncogenic DNA. Cell lines derived from morphologically transformed foci synthesized p29 at 60-75% reduced levels compared with untransformed parental cells. Upon inoculation into syngeneic immunocompetent animals, transformed cells gave rise to tumors which were excised and established in culture. The amount of p29 in both focal and tumor-derived lines was inversely correlated with the latent period for tumor formation. In cell lines with a tumor latency of 12-20 days, the level of p29 was decreased by 90-99%. In rapidly tumorigenic cells with a short latency (3-6 days), p29 synthesis was not detectable. These data demonstrate that p29 may be a sensitive and reliable marker for tumor progression of fibroblasts.

Animals↗
PubMed1986

Localization and comparative nucleotide sequence analysis of the transforming domain in herpes simplex virus DNA containing repetitive genetic elements.

The 7.5-kilobase BamHI E fragment (BamHI-E) of herpes simplex virus type 2 (HSV-2) DNA (map position 0.533-0.583) encodes the 144-kDa subunit of ribonucleotide reductase and induces the neoplastic transformation of immortalized cell lines. To define the minimal transforming region of BamHI-E, a series of subclones were constructed that spanned the entire fragment. These subclones were assayed for focus formation in Rat-2 cells. Removal of the promoter region from the viral 144-kDa-protein gene left the transforming activity of DNA clones intact. A 481-bp Pst I-Sal I subclone of BamHI-E was capable of inducing focus formation and tumorigenic conversion. The nucleotide sequence of this fragment and the colinear nontransforming region of HSV-1 DNA was determined and compared. Striking differences were detected in the structure and organization of repeated sequence elements. Specifically, transforming HSV-2 DNA contains multiple regions of alternating purines and pyrimidines, G + C-rich sequences that are potential binding sites for transcription factor Sp1, and insertion-like sequence elements that are interrupted by base substitutions in nontransforming HSV-1 DNA. These results define a distinct transforming domain in HSV-2 DNA composed of repetitive elements implicated in gene rearrangement and activation.

Base Sequence↗
PubMed1986

DNA amplification and neoplastic transformation mediated by a herpes simplex DNA fragment containing cell-related sequences.

The transforming potential of the herpes simplex virus type 2 (HSV-2) BamHI fragment E (map position 0.533-0.583) encoding the 140-kDa ribonucleotide reductase was assayed by transfection in established Rat-2 cells. Foci of refractile, morphologically distinguishable cells were induced at lower efficiency and after a longer incubation period as compared to the human tumor oncogene EJ-Ha-ras. Focus-derived BamHI fragment E-transformed cell lines formed medium-to-large (0.1-0.25 mm) colonies in soft agar and were tumorigenic in immunocompetent syngeneic rats. Southern blot analysis of normal rat DNA after EcoRI digestion revealed specific DNA segments homologous to HSV-2 BamHI fragment-E DNA. In BamHI fragment E-transformed and tumor-derived lines, about 8- to 30-fold amplification was detected in a subset of the specific HSV-related DNA segments. In addition, extrachromosomal DNA was isolated from transformed cells by plasmid rescue and contained the left-hand 70% of HSV-2 Bam HI fragment E fused to rat DNA. These results indicate the presence in normal cells of nonrepetitive DNA segments, related to the transforming HSV-2 fragment, that can be targeted for genetic alterations associated with neoplastic transformation.

Animals↗
PubMed1983

Neoplastic transformation by a cloned human cytomegalovirus DNA fragment uniquely homologous to one of the transforming regions of herpes simplex virus type 2.

Specific DNA fragments of human cytomegalovirus strain Towne exhibited sequence homology to the transforming regions of herpes simplex virus type 2 (HSV-2) when examined by nitrocellulose filter hybridization under nonstringent conditions. Cloned Towne Xba I fragments B and C were homologous to both Bgl II transforming fragments N and C of HSV-2 DNA, whereas cloned Towne Xba I fragment E was uniquely homologous to HSV-2 Bgl II fragment C. Furthermore, Towne Xba I fragment E exhibited homology to a unique fragment of cytomegalovirus strain AD169 but lacked homology to the recently identified Xba I transforming (focus-forming) fragment N. Normal diploid Syrian hamster embryo cells transfected with cloned Towne Xba I fragment E displayed colonies of refractile, rapidly dividing cells which escaped senescence to form immortal cell lines. At early passages, these lines exhibited growth in 2% serum and formed small (less than 0.1 mm) colonies in 0.3% agarose. Serial passaging resulted in the appearance of large (greater than 0.25 mm) colonies in agarose, indicating the involvement of more than one step in Towne Xba I fragment E-induced transformation of the diploid hamster embryo cells. NIH 3T3 cells transfected with Towne Xba I fragment E rapidly displayed large colonies in agarose and tumors in vivo.

Base Sequence↗
PubMed1983

Characterization and location of myc homologous sequences in human cytomegalovirus DNA.

Specific DNA fragments from human cytomegalovirus (HCMV) strains Towne and AD169 exhibited homology to myc DNA sequences under hybridization conditions corresponding to a 22-28% base mismatch. In a specific subset of hybridizing HCMV fragments, the homology was restricted to the 5' half of viral v-myc and the 5' half of human c-myc. No hybridization was observed between HCMV fragments and the 3' v-myc and 3' human c-myc probes. In Towne DNA, myc homologous sequences mapped in four regions within the long unique segment (0.070-0.094, 0.134-0.156, 0.454-0.470, and 0.591-0.605 map unit) and one region in each of the short terminal repeats (0.832-0.847 and 0.984-1.0 map unit). In strain AD169, myc homology mapped in three regions within the long unique segment (0.123-0.147, 0.174-0.198, and 0.583-0.606 map unit) and one region in each of the short terminal repeats (0.833-0.863 and 0.976-1.0 map unit). By utilizing probes specific for the 5' and 3' portions of v-myc and human c-myc, we established that the regions of homology in a specific subset of HCMV restriction fragments corresponded to the 5' half of myc and were not due to MC29 viral helper sequences, flanking cellular sequences, or binding of probe to G.C-rich DNA.

Base Sequence↗
PubMed1983

Immortalization and neoplastic transformation of normal diploid cells by defined cloned DNA fragments of herpes simplex virus type 2.

Diploid Syrian hamster embryo (SHE) cells were passaged after transfection with recombinant plasmids containing herpes simplex virus type 2 (HSV-2) DNA inserts Bgl II focus-forming fragment N, Bgl II transforming fragment C, and EcoRI/HindIII fragment AE. Cultures transfected with salmon DNA or with 0.1-5.0 micrograms of Bgl II fragment N reached crisis and senesced. Those transfected with 0.1-0.5 micrograms of Bgl II fragment C or its left-hand 64% subclone EcoRI/HindIII fragment AE escaped senescence and formed continuous lines. At early passages, these lines as well as isolated clones grew in 2% serum but formed small (less than or equal to 0.1 mm) colonies in 0.3% agarose and were nontumorigenic. Serial passaging of Bgl II fragment C-induced cultures and isolated clones resulted in the appearance of large (greater than 0.25 mm) colonies in agarose followed by tumorigenicity. This behavior was not exhibited by the EcoRI/HindIII fragment AE-induced cultures that remained nontumorigenic after 53 passages. DNA from normal SHE cells exhibited homology to Bgl II fragment C but, under relatively stringent conditions, DNAs from transformed and tumor-derived lines exhibited discrete hybridizing bands comigrating with authentic viral fragments. These results indicate that neoplastic transformation of normal diploid SHE cells by HSV-2 DNA fragments involves at least two distinct steps--i.e., immortalization and conversion to tumorigenicity. EcoRI/HindIII fragment AE representing the left 64% of Bgl II fragment C is sufficient to induce immortalization. However, DNA sequences from both left-hand 64% and right-hand 36% subfragments of Bgl II fragment C are required for tumorigenic transformation.

Animals↗
PubMed1980

The reactivation of human interferons by guanidine thiocyanate.

The addition of 1.5 M guanidine thiocyanate (GuSCN) reactivates inactive human leukocyte interferon. The biological activity of inactivated human fibroblast interferon can be only partially recovered with GuSCN if additional (thermal) energy is supplied.

Fibroblasts↗