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B Su

Publications and source records attributed to B Su.

At least 55 records · Page 3Linked to original sources
PubMed2000

Do the CK18 related proteins change in general in epithelial cancers?

The modulation of cytokeratin 18 during tumor transformation in hepatoma had been previously recognized through a series of biochemical and immunological approaches. Expression of cytokeratin 18 in transitional cell carcinoma comparing with hepatoma was investigated using the hepatoma transformation model. CK18 related molecules were found. In the present study, we design various epithelial cancers with the same model. CK18 related molecules were all evident. Therefore, we suggest that CK18 related proteins would play an important role in tumorigenesis of epithelial cancers.

Carcinoma, Hepatocellular↗
PubMed2000

[Tn5 mutagenesis and the characteristics of indole-3-acetic acid biosynthesis in Alcaligenes faecalis A1501].

The IAA production of Alcaligenes faecalis wild type strain A1501 depended on addition of L-tryptopham(trp). A1501 could grow well in minimal medium without Trp, but could not produce IAA. The results indicated that there was Trp-dependent IAA biosynthesis pathway in A. faecalis A1501. A1501 shows a characteristic of cell density-dependent IAA biosynthesis. The Tn5-induced mutant bank of A1501 was constructed using Tn5 mutagenesis and one Trp auxotrophic mutant AT63 was selected and identified. The Tn5-induced mutant AT63 could synthesis 2.24 micrograms/mL IAA in minimal medium without L-Trp. It indicated there were at least two IAA biosynthesis pathways in A. faecalis, one needed Trp, the other needed IGP as precursor. The results of southern hybridization also suggested that the Tn5-insertion might locate in gene locus encoded IAA synthetase.

Alcaligenes faecalis↗
PubMed1999

The utility of short tandem repeat loci beyond human identification: implications for development of new DNA typing systems.

Since the first characterization of the population genetic properties of repeat polymorphisms, the number of short tandem repeat (STR) loci validated for forensic use has now grown to at least 13. Worldwide variations of allele frequencies at these loci have been studied, showing that variations of interpopulation diversity at these loci do not compromise the power of identification of individuals. However, data collected for validation of these loci for forensic use has utility beyond human identification; the origin and past migration history of modern humans can be reconstructed from worldwide variations at these loci. Furthermore, complex forensic cases previously unresolvable can now be investigated with the help of the validated STR loci. Here, we provide the absolute power of the validated set of 13 STR loci for addressing these issues using multilocus genotype data on 1,401 individuals belonging to seven populations (US European-American, US African-American, Jamaican, Italian, Swiss, Chinese and Apache Native-American). Genomic research is discovering new classes of polymorphic loci (such as the single nucleotide polymorphisms, SNPs) and lineage markers (such as the mitochondrial DNA and Y-chromosome markers); our aim, therefore, was to determine how many SNP loci are needed to match the power of this set of 13 STR loci. We conclude that the current set of STR loci is adequate for addressing most problems of human identification (including interpretations of DNA mixtures). However, if suitable number of SNPs are used that would match the power of the STR loci, they alone cannot resolve more complex cases unless they are supplemented by the validated STR loci.

Chromosome Mapping↗
PubMed1999

Phylogenetic study of complete cytochrome b genes in musk deer (genus Moschus) using museum samples.

As an endangered animal group, musk deer (genus Moschus) are not only a great concern of wildlife conservation, but also of special interest to evolutionary studies due to long-standing arguments on the taxonomic and phylogenetic associations in this group. Using museum samples, we sequenced complete mitochondrial cytochrome b genes (1140 bp) of all suggested species of musk deer in order to reconstruct their phylogenetic history through molecular information. Our results showed that the cytochrome b gene tree is rather robust and concurred for all the algorithms employed (parsimony, maximum likelihood, and distance methods). Further, the relative rate test indicated a constant sequence substitution rate among all the species, permitting the dating of divergence events by molecular clock. According to the molecular topology, M. moschiferus branched off the earliest from a common ancestor of musk deer (about 700,000 years ago); then followed the bifurcation forming the M. berezovskii lineage and the lineage clustering M. fuscus, M. chrysogaster, and M. leucogaster (around 370,000 years before present). Interestingly, the most recent speciation event in musk deer happened rather recently (140,000 years ago), which might have resulted from the diversified habitats and geographic barriers in southwest China caused by gigantic movements of the Qinghai-Tibetan Plateau in history. Combining the data of current distributions, fossil records, and molecular data of this study, we suggest that the historical dispersion of musk deer might be from north to south in China. Additionally, in our further analyses involving other pecora species, musk deer was strongly supported as a monophyletic group and a valid family in Artiodactyla, closely related to Cervidae.

Animals↗
PubMed1999

Signal transduction-mediated adherence and entry of Helicobacter pylori into cultured cells.

BACKGROUND & AIMS: An ability to invade host cells could be a means for Helicobacter pylori to achieve resistance to antibiotic therapy. The aim of this study was to investigate the mechanisms involved in adherence and entry of H. pylori into cultured cells. METHODS: Coinfection with Yersinia expressing mutant or wild-type YopH tyrosine phosphatase was used. Genistein and cytochalasin D were used as inhibitors of adherence and entry; entry was monitored by a gentamicin-protection assay. Target cells were AGS cells and a beta1-integrin-deficient cell line with its corresponding beta1-integrin-expressing transfectant. RESULTS: H. pylori induced phosphorylation of 125-130-kilodalton proteins, similar in size to the target proteins of Yersinia YopH. Adherence of H. pylori was inhibited by Yersinia organisms expressing enzymatically active YopH but not by inactive YopH. Adherence and entry of H. pylori was considerably higher with beta1-integrin-transfected cells than with beta1-integrin-deficient cells. Antibodies directed against alpha5- and beta1-integrin chains reduced adherence to the alpha5beta1-integrin-expressing gastric cell line AGS. Entry was inhibited by both cytochalasin D and genistein. Entry, but not adherence, was higher for 2 type I strains than for a type II isolate. CONCLUSIONS: Invasion of gastric epithelium via an integrin-mediated pathway could contribute to the ability of H. pylori to establish persistent infection.

Bacterial Adhesion↗
PubMed1999

Lignan and phenylpropanoid glycosides from Lancea tibetica and their antitumor activity.

A new lignan glucoside, the first 7,9'-monoepoxyte-trahydrofuran type lignan with the cis-relationship of H-7 and H-8, named tibeticoside (1), as well as ten known compounds have been isolated from the medicinal plant (roots, stems and leaves) Lancea tibetica. The structure of tibeticoside (1) has been elucidated on the basis of chemical and spectral evidence, especially by 2D-NMR (1H-1H COSY, HMQC, HMBC, NOESY). In addition, sylvatesmin (6) exhibited effective antitumor activity on B16 cells.

Animals↗
PubMed1999

Distribution of two HIV-1-resistant polymorphisms (SDF1-3'A and CCR2-64I) in East Asian and world populations and its implication in AIDS epidemiology.

Chemokine receptor CCR2 and stromal-derived factor (SDF-1) are involved in HIV infection and AIDS symptom onset. Recent cohort studies showed that point mutations in these two genes, CCR2-64I and SDF1-3'A, can delay AIDS onset > or = 16 years after seroconversions. The protective effect of CCR2-64I is dominant, whereas that of SDF1-3'A is recessive. SDF1-3'A homozygotes also showed possible protection against HIV-1 infection. In this study, we surveyed the frequency distributions of the two alleles at both loci in world populations, with emphasis on those in east Asia. The CCR2-64I frequencies do not vary significantly in the different continents, having a range of 0.1-0.2 in most populations. A decreasing cline of the CCR2-64I frequency from north to south was observed in east Asia. In contrast, the distribution of SDF1-3'A in world populations varies substantially, and the highest frequency was observed in Oceanian populations. Moreover, an increasing cline of the SDF1-3'A frequency from north to south was observed in east Asia. The relative hazard values were computed to evaluate the risk of AIDS onset on the basis of two-locus genotypes in the east Asian and world populations.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Y-Chromosome evidence for a northward migration of modern humans into Eastern Asia during the last Ice Age.

The timing and nature of the arrival and the subsequent expansion of modern humans into eastern Asia remains controversial. Using Y-chromosome biallelic markers, we investigated the ancient human-migration patterns in eastern Asia. Our data indicate that southern populations in eastern Asia are much more polymorphic than northern populations, which have only a subset of the southern haplotypes. This pattern indicates that the first settlement of modern humans in eastern Asia occurred in mainland Southeast Asia during the last Ice Age, coinciding with the absence of human fossils in eastern Asia, 50,000-100,000 years ago. After the initial peopling, a great northward migration extended into northern China and Siberia.

Africa↗
PubMed1999

The expression of cytokeratin 18 in transitional cell carcinoma comparing with hepatoma.

The epithelium in kidneys and urinary bladders contain CK18 as in liver cells. The modulation of cytokeratin 18 during tumor transformation in hepatoma had been previously recognized through a series of biochemical and immunological approaches. A 14 KD hepatoma related molecules was found in the previous studies. We would like to utilize the hepatoma transformation model to study the changes in CK18 in transitional cell carcinoma, using immunoblotting and western blotting techniques. The result is that transitional cell carcinoma retain their CK18 molecule. Furthermore, CK18 related molecules similar to those seen in hepatoma also present in transitional cell carcinoma. The conclusions are transitional cell carcinoma contains CK18 related proteins similar to those seen in hepatoma tissues. We suggest that this element would be responsible for the change during the malignant transformation processes.

Blotting, Western↗
PubMed1999

Stabilizing of cytokeratin in PLC/PRF/5 cells.

There are two sorted groups of cytokeratin 18 (CK18) in forms of assembly and disassembly in PLC/PRF/5 cells. A subcellular shifting is found in association with conditions of microtubule networks. The finding shows that CK18 mostly in forms of assembly, when microtubule networks are in status. The result also reveals that CK18 is relatively in forms of disassembly, while microtubule networks are disrupted in steps. It indicates that intact microtubule networks are probably a stabilizing factor of assembled CK18. It implies that CK18 is not a stable molecule when the cell is under environmental stress.

Blotting, Western↗
PubMed1998

JNKK1 organizes a MAP kinase module through specific and sequential interactions with upstream and downstream components mediated by its amino-terminal extension.

MAP kinase (MAPK) cascades are composed of a MAPK, MAPK kinase (MAPKK), and a MAPKK kinase (MAPKKK). Despite the existence of numerous components and ample opportunities for crosstalk, most MAPKs are specifically and distinctly activated. We investigated the basis for specific activation of the JNK subgroup of MAPKs. The specificity of JNK activation is determined by the MAPKK JNKK1, which interacts with the MAPKKK MEKK1 and JNK through its amino-terminal extension. Inactive JNKK1 mutants can disrupt JNK activation by MEKK1 or tumor necrosis factor (TNF) in intact cells only if they contain an intact amino-terminal extension. Mutations in this region interfere with the ability of JNKK1 to respond to TNF but do not affect its activation by physical stressors. As JNK and MEKK1 compete for binding to JNKK1 and activation of JNKK1 prevents its binding to MEKK1, activation of this module is likely to occur through sequential MEKK1:JNKK1 and JNKK1:JNK interactions. These results underscore a role for the amino-terminal extension of MAPKKs in determination of response specificity.

Animals↗
PubMed1998

Molecular cloning and characterization of a human protein kinase that specifically activates c-Jun N-terminal kinase.

The c-Jun N-terminal kinases (JNKs), also called stress-activated protein kinases (SAPKs), belong to the mitogen-activated protein kinase (MAPK) gene super-family. Like all the MAPKs, JNKs are activated through dual phosphorylation of a theronine residue and a tyrosine residue by a dual specificity kinase such as JNKK1/MKK4/SEK1. Here, we report the molecular cloning and characterization of hJNKK2 alpha, a human homolog of the recently reported murine MKK7 alpha. hJNKK2 alpha belongs to the MAPK kinase gene family and is expressed in many adult tissues. It is nearly identical to a recently reported human JNKK2 at the kinase domain but with major differences in both amino- and carboxyl-terminal sequences, suggesting that hJNKK2 alpha may be an alternative spliced form of this kinase. Expression of hJNKK2 alpha, but not its related kinases JNKK1/MKK4/SEK1, MEK1, MKK3, or MKK6, leads to strong activation of JNK in several cell lines. No activation of ERK or p38 kinases was observed with this kinase. An in-vitro kinase assay demonstrated that JNK1 activation by hJNKK2 alpha requires phosphorylation of the theronine and tyrosine residues at positions 183 and 185 in JNK1. Furthermore, hJNKK2 alpha activated the JNK-dependent signal transduction pathway in vivo by induction of c-Jun- and ATF2-mediated gene transcription. In conclusion, we have cloned the human homolog of murine MKK7 alpha, which may be an alternative spliced form of human JNKK2 involved in transducing specific upstream signals to regulate JNK activity in vivo.

Adult↗
PubMed1998

Cardiac hypertrophy induced by mitogen-activated protein kinase kinase 7, a specific activator for c-Jun NH2-terminal kinase in ventricular muscle cells.

Activation of stress-activated protein kinases, including the p38 and the c-Jun NH2-terminal kinases (JNK), have been associated with the onset of cardiac hypertrophy and cell death in response to hemodynamic overload and ischemia/reperfusion injury. Upon infection of cultured neonatal rat cardiac myocytes with recombinant adenoviral vectors expressing a wild type and a constitutively active mutant of MKK7 (or JNKK2), JNK was specifically activated without affecting other mitogen-activated protein kinases, including extracellular signal-regulated protein kinases and p38. Specific activation of the JNK pathway in cardiac myocytes induced characteristic features of hypertrophy, including an increase in cell size, elevated expression of atrial natriuretic factor, and induction of sarcomere organization. In contrast, co-activation of both JNK (by MKK7) and p38 (by MKK3 or MKK6) in cardiomyocytes led to an induction of cytopathic responses and suppression of hypertrophic responses. These data provide the first direct evidence that activation of JNK alone is sufficient to induce characteristic features of cardiac hypertrophy, thereby supporting an active role for the JNK pathway in the development of cardiac hypertrophy. The cytopathic response, as a result of co-activation of both JNK and p38, may contribute to the loss of contractile function and viability of cardiomyocytes following hemodynamic overload and cardiac ischemia/reperfusion injury.

Adenoviridae↗
PubMed1998

Activation of cytokine production, tumoricidal properties, and tyrosine phosphorylation of MAPKs in human monocytes by a new synthetic lipopeptide, JBT3002.

We investigated the expression of cytokine genes and tumoricidal properties in human blood monocytes in response to a new synthetic immunomodulating lipopeptide, JBT3002. Incubation of peripheral blood monocytes with free-form JBT3002 or JBT3002 encapsulated in multilamellar phospholipid vesicles (liposomes, MLV-JBT3002) induced tumoricidal properties in a dose-dependent manner. Both MLV-JBT3002 and free-form JBT3002 induced production of tumor necrosis factor alpha, interleukin-1beta, and interleukin-6 in a dose-dependent manner with similar kinetics. Treatment of monocytes with interferon-gamma did not significantly alter the expression of cytokine genes but increased the expression of cytokines induced by MLV-JBT3002 and free-form JBT3002. In contrast to monocyte activation by lipopolysaccharide (LPS), activation by JBT3002 was independent of serum and was not inhibited by CD14-neutralizing antibody. Incubation of monocytes with JBT3002 induced a rapid increase in tyrosine phosphorylation of proteins with apparent molecular masses of 42 and 38 kDa, a migration band shift of c-Jun NH2-terminal kinase 1 (JNK1), and activation of extracellular signaling regulated kinases. Consistent with its effect on cytokine expression, stimulation of these intracellular signaling pathways by JBT3002 was not inhibited in serum-free conditions. Collectively, the data indicate that the synthetic lipopeptide JBT3002 is a potent monocyte activator that modulates monocyte function by mechanisms similar to LPS but by a distinct receptor.

Adjuvants, Immunologic↗
PubMed1998

Genetic diversity of Yunnan local pig breeds inferred from blood protein electrophoresis.

Protein electrophoresis was used to examine the blood protein polymorphism in Yunnan local pig breeds, i.e., the Saba pig, Dahe pig, and Diannan small-ear pig breeds. Of 38 genetic loci surveyed, 9 were found to be polymorphic. The percentage of polymorphic loci (P) varies from 0.1875 to 0.2121, and the mean individual heterozygosity (H) varies from 0.0712 to 0.1027 in three pig breeds. The results indicate that blood protein polymorphism in Yunnan pig breeds is high. Yunnan local pig breeds have a wealth of genetic diversity at the level of blood proteins.

Animals↗
PubMed1998

Type I Helicobacter pylori shows Lewis(b)-independent adherence to gastric cells requiring de novo protein synthesis in both host and bacteria.

Type I Helicobacter pylori strains frequently recognize the Lewisb (Leb) blood group antigen. This binding property and expression of the Leb oligosaccharide were required for adherence to fixed normal or pathologic gastric tissue. In contrast, both type I and type II strains adhered to cultured cells in the absence of the Leb epitope. For the gastric cell line AGS, adherence was significantly higher when viable type I strains were allowed to interact with viable AGS cells compared with fixed cells. The observation that chloramphenicol and cycloheximide, inhibitors of bacterial and eukaryotic protein synthesis, respectively, significantly reduced adherence of type I but not type II isolates suggests that in type I strains, adherence depends on the up-regulation of one or more host cell receptors triggered by the bacterium.

Bacterial Adhesion↗
PubMed1998

Virulence and colonization-associated properties of Helicobacter pylori isolated from children and adolescents.

Helicobacter pylori isolates from 32 children and adolescents were characterized with respect to putative virulence and colonization-associated properties. Only 3 of the subjects had duodenal ulcer. All but 2 of the remaining 29 had various degrees of chronic gastric inflammation. No significant correlation between degree of inflammation and presence of the cag-pathogenicity island, cytotoxin production, vacA alleles associated with cytotoxin expression, and binding ability to the Lewis(b) (Le[b]) oligosaccharide was found. Only 4 isolates expressed the Le(b)-specific adhesin, of which 3 were also cag region-positive. This is in contrast to adults with gastritis or peptic ulcer disease (or both), in whom most of the H. pylori isolates bind Le(b). In an in situ binding assay H. pylori were less able to adhere to gastric surface mucous cells in biopsies taken from children compared with adults, suggesting a lower expression of the Le(b) oligosaccharide in the children.

Adolescent↗