Mekk3 is essential for early embryonic cardiovascular development

The early development of blood vessels consists of two phases, vasculogenesis and angiogenesis, which involve distinct and also overlapping molecular regulators, but the intracellular signal transduction pathways involved in these processes have not been well defined. We disrupted Map3k3 (also known as Mekk3), which encodes Mekk3, a member of the Mekk/Ste11 family, in mice. Map3k3-/- embryos died at approximately embryonic day (E) 11, displaying disruption of blood vessel development and the structural integrity of the yolk sac. Angiogenesis was blocked at approximately E9.5 in mutant embryos. Map3k3 disruption did not alter the expression of the genes encoding Vegf-1, angiopoietin or their receptors. The development of embryonic, but not maternal, blood vessels in the placentas of Map3k3-/- embryos was impaired, revealing an intrinsic defect in Map3k3-/- endothelial cells. Moreover, Mekk3 activated myocyte-specific enhancer factor 2C (Mef2c), a transcription factor crucial for early embryonic cardiovascular development through the p38 mitogen-activated protein kinase (Mapk) cascade. We conclude that Mekk3 is necessary for blood vessel development and may be a possible target for drugs that control angiogenesis.

World population data for the HLA-DQA1, PM and D1S80 loci with least and most common profile frequencies for combinations of loci estimated following NRC II guidelines

All published and unpublished gene frequency data for the PCR-based loci HLA-DQA1, LDLR, GYPA, HBGG, D7S8, GC, and D1S80 that could be located are presented in summary tables. These gene frequencies provide the data necessary for estimating probabilities of chance match according to NRC II guidelines for any DNA profile that includes any combination of these loci for any of the populations. To illustrate the range of polymorphism for combined locus profiles, least and most common profile frequencies were estimated following NRC II guidelines for: the PM loci for all populations for which PM data were available; and for combinations of HLA-DQA1/PM, HLA-DQA1/D1S80, PM/D1S80, and HLA-DQA1/ PM/D1S80 for populations for which data were available for the relevant combinations. The profile frequencies were calculated at theta values of zero and 0.01. Minimum allele frequencies (MAF) were calculated, and are shown, for each data set for which the MAF was greater than the lowest observed allele frequency. Least common profile frequencies were calculated using MAF in those cases to illustrate a conservative estimate. The effect of using MAF versus lowest observed allele frequency in estimating least common profile frequencies is briefly illustrated as well. We finally show that aggregate U.S. gene frequency data for the classical MN and GC polymorphisms for both Caucasian and African-American populations is fully in accord with the DNA-based gene frequency data obtained from PM reverse dot-blot strips for GYPA and GC, respectively.

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.

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.

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.

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.

[Isolation and identification of N2-fixing strains of Bacillus in rice rhizosphere of the Yangtze River Valley]

Rice rhizosphere soil samples were colected from 10 sites of 7 provinces in the Yangzi River Valley, and from the soil samples 16 endospore-forming strains with ARA (Acetylene Reduction Activity) were isolated, the nitrogen fixing ability was tested by the method of 15N tracer and the atom 15N% excess are ranged from 0.0297% to 0.4714%. The strains were identified as Bacillus licheniformis, B. subtilis, B. azotoformans, B. cereus, B. pumilus, B. brevis, B. megaterium, B. firmu.

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.

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.

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.

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.

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.

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.

[The effect of removable partial denture on the composition of bacteria on the apt-to-decay site of abutment teeth]

This study was aimed at the composition of plaques which were on the base teeth's carious sensitive sites, just after the insertion of the removable partial denture (RPD). The results showed that the ratios of bacterial detection in different teeth at the same period and those on the different sites of same teeth at different periods were not significantly different. There was a tendency that the detection ratio of the stomatococcus at the early period was higher than that of other bacteria, but at the middle period the ratios declined, and at the late period it was higher again. The detection ratio of the bacillus was on the contrary in the study. At the same time, the composition of the plaques changed significantly after the dentures had been used for 7, 14, and 21 days and 3 months. After 3 months, the ratios of the stomatococcus and the bacillas returned to their normal levels. The 3 main cariogenic bacteria were all detected in this study. The Streptococcus mutant was the dominant bacterium in the plaques and its ratio went up with the time duration. The ratio for the lower second molar was higher than that for the mandibular second premolar (P < 0.05). The detection ratios of the Actinomyces viscosus and lactobacillus were lower. In conclusion, after the insertion of RPD, the oral microbial ecosystem would be changed and the cariogenic bacteria began to implant on the surface of the base teeth. So RPD is a potential factor to cause the caries.

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.

Differentiation of human gastric adenocarcinoma cell line MGc80-3 induced by verbascoside

Verbascoside is a natural antioxidant extracted from Pedicularis striata Pall (Jueyehesen). After being treated with 20 mumol/l verbascoside, the growth curve and mitotic index of human gastric adenocarcinoma MGc80-3 cells decreased remarkably, cell doubling time was delayed, the cellular growth inhibitory rate amounted to 53.2%, cell surface charge assayed by cell electrophoresis obviously changed, the electrophoresis rate dropped from 3.51 microns/s/v/cm to 2.74, i.e., the percent of retardation reached 28.4%. There was a 75% decrease of the tumorigenicity for the treated cells compared with the untreated cells inoculated subcutaneously in BALB/C nude mice. Scanning electron microscopy revealed that the microvilli on the surface of treated cells had been reduced obviously. It confirmed that verbascoside, similar to DMSO, could reverse MGc80-3 cells' malignant phenotypic characteristics and induced redifferentiation of MGc80-3 cells.

Tissue factor positions and maintains the factor VIIa active site far above the membrane surface even in the absence of the factor VIIa Gla domain. A fluorescence resonance energy transfer study

Coagulation factor VIIa (fVIIa), a soluble serine protease, exhibits full proteolytic activity only when bound to its cofactor, tissue factor (TF). Both proteins interact with membranes; TF is an integral membrane protein, while fVIIa binds reversibly to phospholipid surfaces via its Gla domain. In this study, we examine the extent to which the location of the fVIIa active site in the fVIIa.TF complex is determined by the fVIIa Gla domain. A fluorescein dye was covalently attached to the active site of fVIIa lacking the Gla domain (Gla domainless fVIIa, GD-fVIIa) via a tripeptide tether to yield fluorescein-D-Phe-Pro-Arg-GD-fVIIa (Fl-FPR-GD-fVIIa). The location of the active site of GD-fVIIa relative to the membrane surface was determined using fluorescence resonance energy transfer between the fluorescein dye in the active site of GD-fVIIa and octadecylrhodamine (OR) at the surface of phospholipid vesicles. As expected, no energy transfer was observed between Fl-FPR-GD-fVIIa and OR in vesicles composed of phosphatidylcholine/phosphatidylserine (PC/PS, 4:1) because the Gla domain is required for the binding of fVIIa to phospholipid. However, when Fl-FPR-GD-fVIIa was titrated with PC or PC/PS vesicles into which purified TF had been reconstituted, energy transfer was observed. Based on the dependence of fluorescence resonance energy transfer on OR density, the average distance of closest approach between fluorescein in the active site of Fl-FPR-GD-fVIIa.TF and OR at the vesicle surface was determined to be 78 A (kappa2 = (2)/(3)). Since this value is nearly the same as that obtained with intact Fl-FPR-fVIIa bound to TF, the presence or absence of the fVIIa Gla domain has only a small effect on the location of the active site in the fVIIa.TF complex. The extracellular domain of tissue factor therefore must be fairly rigid and fixed relative to the surface to position and maintain the fVIIa active site far above the membrane even in the absence of the fVIIa Gla domain.

Dynamic regulation of c-Jun N-terminal kinase activity in mouse brain by environmental stimuli

Activation of the recently identified c-Jun N-terminal kinases (JNKs) typically results in programmed cell death (apoptosis) in neurons and other cell types grown in culture. However, the effects of JNK activation in the central nervous system in vivo are unknown. At baseline, JNK activity in mice was on average 17-fold higher in brain than in peripheral organs, whereas JNK protein levels were similar. In brain, JNK was expressed primarily in neurons. Restraining mice or allowing them to explore a novel environment rapidly increased JNK activity 3- to 15-fold in various brain regions, but these manipulations did not increase brain activity of the extracellular signal-regulated kinase. Because noninvasive environmental stimuli that do not induce neurodegeneration elicited prominent increases in JNK activity in the brain, we conclude that acute activation of the JNK cascade in central nervous system neurons does not induce neuronal apoptosis in vivo. In contrast, the high baseline activity of JNK in the brain and the activation of the JNK cascade by environmental stimuli suggest that this kinase may play an important physiological role in neuronal function.

[Extraction and sequencing of trace DNA from cornu Cervi pantotrichum]

The trace DNA extraction method was used to extract DNA from the blood, hair, Cornu cervi pantotrichum, hairy antler of the sika deer, Cervus nippon, and penis of Bulbalus bublis and Asinus vulgaris. A 307 bp fragment of mitochondrial DNA cytochrome b gene was amplified with primers L14841 and H15149 for these extractions. The purified PCR products were sequenced by the dideoxy method. DNA sequence obtained from the Cornu cervi pantotrichum is the same as that obtained from the fresh blood and hair of the sika deer, but the sequence of the so-called hairy antler is quite different, implying that it is not from the sika deer. In addition, the phylogenetic relationships among different species are congruent with the traditional known phylogeny.

[Genetic divergence of Cordyceps sinensis as estimated by random amplified polymorphic DNA analysis]

Random amplified polymorphic DNA(RAPD) has been used in analyzing 13 winter worm, summer grasses (Cordyceps sinensis [Berk.], Sacc.) from 5 areas in Qingzang plateau. For 19 arbitrary primers, each individual showed about 65 RAPD markers. The genetic distances among those 13 winter worm, summer grasses were correlated to their geographic distances. Molecular phylogenetic tree constructed by UPGMA and NJ suggested that 13 winter worm, summer grasses could be divided into 3 clusters: east cluster, north cluster and middle cluster, in consistence with their origins and genetic divergence among different clusters. Furthermore, our results implied that the RAPD markers of winter worm, summer grasses showed a geographic specificity and could be a better genetic marker in studying genetic diversity and phylogeny of winter worm, summer grasses.