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S Tungpradabkul

Publications and source records attributed to S Tungpradabkul.

7 recordsLinked to original sources
PubMed2006

Burkholderia pseudomallei RpoS regulates multinucleated giant cell formation and inducible nitric oxide synthase expression in mouse macrophage cell line (RAW 264.7).

Burkholderia pseudomallei is the causative agent of melioidosis. This bacterium can invade and survive inside the phagocytic and nonphagocytic cells. After internalization, the bacteria can escape from the membrane-bound phagosome into the cytoplasm. Internalised B. pseudomallei can also induce a cell-to-cell fusion, resulting in a multinucleated giant cell (MNGC) formation. In the present study, we demonstrated that B. pseudomallei rpoS null mutant was similar to its wild type parent in its ability to survive and multiply inside the mouse macrophages, but it failed to stimulate MNGC formation. The rpoS mutant was also unable to activate inducible Nitric Oxide Synthase (iNOS) in resting mouse macrophages but in gamma interferon (IFN-gamma)-activated macrophages, the mutant was able to induce significantly higher levels of iNOS and NO when compared with its wild-type counterpart, resulting in a significantly lower number of bacteria inside the infected host cells.

Animals↗
PubMed1999

PCR-RFLP analysis of the flagellin sequences for identification of Burkholderia pseudomallei and Burkholderia cepacia from clinical isolates.

The flagellin genes of four Burkholderia pseudomallei and two Burkholderia cepacia clinical isolates were studied by a polymerase chain reaction (PCR)-based isolation method using the same pair of primers. The PCR-amplification products of the isolates showed a single band of about 1.1 kb, which is similar to a type II B. cepacia flagellin reported previously. In order to distinguish these two species based on the flagellin PCR-amplified products, Pst I and Xho I restriction endonuclease analysis was performed. The results suggest that there is sufficient diversity within the flagellin sequences of the closely related Burkholderia species, B. pseudomallei and B. cepacia, to enable flagellin-type identification on the basis of the pattern of restriction fragments. In addition, the flagellin gene should be of considerable use as a genetic marker for clinical identification of these organisms.

Amino Acid Sequence↗
PubMed1999

Stable marker on flagellin gene sequences related to arabinose non-assimilating pathogenic Burkholderia pseudomallei.

Using PCR-based isolation and sequence analysis of the flagellin gene from two distinct biotypes of Burkholderia pseudomallei, a 15-bp deletion was found within the variable domain of the gene in isolates capable of assimilating arabinose (Ara+). This finding led to the development of a PCR-based method in order to differentiate and identify pathogenic B. pseudomallei for epidemiological study. A pair of specific primers was designed covering the 15-bp deletion region at the variable domain. PCR-amplification products of 176 and 191 bp in size were detected from 41 Ara+ isolates and 39 Ara - isolates of B. pseudomallei, respectively. Moreover, flagellin gene fragments of other bacterial species tested in this study were not amplified using these primers. The results suggest that the flagellin gene sequences of both B. pseudomallei biotypes in this region are stable and distinct. This method can be applied and useful for the epidemiological study of B. pseudomallei.

Amino Acid Sequence↗
PubMed1996

Development of new cloning vectors for the production of immunogenic outer membrane fusion proteins in Escherichia coli.

The Pseudomonas aeruginosa lipoprotein gene (oprI) was modified by cloning an in-frame polylinker in both orientations at the end of oprI. The resulting plasmids pVUB1 and pVUB2 allow high lipoprotein production in E. coli after IPTG induction. The modified lipoproteins are present in the outer membrane and surface-exposed. Outer membrane-bound fusion proteins of different sizes were produced and used to generate antibodies without use of adjuvant. An 87 bp DNA fragment from the vp72 capsid protein gene of African Swine Fever virus (ASFV) and the entire Leishmania major glycoprotein gp63 gene were expressed in this system. Finally, a fusion lipoprotein containing a 16 amino acid epitope from the pre-S2b region of Hepatitis B virus (HBV) was presented by an antigen-presenting cell line to a T-cell hybridoma while the corresponding cross-linked S2b peptide was not. The results suggest that OprI-based fusion proteins can be used to generate both humoral and cellular immune responses.

African Swine Fever Virus↗
PubMed1993

Phosphorylation of infected erythrocyte membrane proteins in Plasmodium chabaudi.

We identify phosphoproteins that are associated to the infected erythrocyte membrane of Plasmodium chabaudi. The specific antibodies that recognize the erythrocyte membrane-associated antigens, namely PcEMA1 and PcLEMA, are studied. According to sequencing analysis, neither the gene structure nor the predicted properties of these two antigens are completely distinct. The PcEMA1 is a 50 kDa acidic protein, with a pI of about 4.4, that contains 25 phosphorylation sites principally located in the repetitive sequence. Almost all of this molecule is hydrophilic. The predicted (predictment ability) of this protein is, hence, associated to the host's erythrocyte cytoskeleton and it is synthesized through an entire erythrocyte cycle. PcLEMA, instead, is a 74 kDa basic protein, with a pI of about 9.8, that contains 11 possible phosphorylation sites. This gene contains two exons: exon 1 shows transmembrane characteristics while exon 2 contains part of the hydrophilic repetitive sequences. Thus this protein is predicted as a transmembrane-associated protein and is synthesized only at the last stages of the erythrocytic cycle. In in-vitro phosphorylation experiments, both PcEMA1 and PcLEMA are phosphorylated by endogenous kinases activities. However, the degree of phosphorylation differs between the two in that PcEMA1 reveals a higher phosphorylation intensity than PcLEMA.

Animals↗
PubMed1983

Analysis of DNA from various species and strains of malaria parasites by restriction endonuclease fingerprinting.

1. DNA from various rodent Plasmodium species and strains and from P. falciparum, the human parasite, were analysed by agarose gel electrophoresis following digestion with restriction endonucleases EcoRI, Hind III and Bam Hl. Complex patterns of ethidium-stained bands were obtained, which showed similarity but reproducible differences among the various parasite species (P. chabaudi, P. yoelii, P. berghei and P. falciparum). 2. No differences could be discerned among two cloned strains of P. yoelii (33X, and YM) and among pyrimethamine-resistant (pyrimethamine + chloroquine)-resistant and the drug-sensitive P. chabaudi clone from which the resistant clones were derived. 3. From the known complexity of Plasmodium DNA it could be concluded that the visible bands were derived from repetitive DNA fractions.

Animals↗