Characterization of the meta-cleavage compound hydrolase gene involved in degradation of the lignin-related biphenyl structure by Sphingomonas paucimobilis SYK-6

Sphingomonas paucimobilis SYK-6 has the ability to transform a lignin-related biphenyl compound, 2,2'-dihydroxy-3,3'-dimethoxy-5, 5'-dicarboxybiphenyl (DDVA), to 5-carboxyvanillic acid (5CVA) via 2, 2',3-trihydroxy-3'-methoxy-5,5'-dicarboxybiphenyl (OH-DDVA). In the 4.9-kb HindIII fragment containing the OH-DDVA meta-cleavage dioxygenase gene (ligZ), we found a novel hydrolase gene (ligY) responsible for the conversion of the meta-cleavage compound of OH-DDVA to 5CVA. Incorporation of 18O from H218O into 5CVA indicated there was a hydrolytic conversion of the OH-DDVA meta-cleavage compound to 5CVA. LigY exhibited hydrolase activity only toward the meta-cleavage compound of OH-DDVA, suggesting its restricted substrate specificity.

[Study on telomerase inhibition by ribozyme targeted to telomerase RNA component]

OBJECTIVE

To evaluate the possibility of using ribozyme technology for telomerase inhibition and cancer therapy.

METHODS

A hammer head ribozyme (telomerase ribozyme, teloRZ) directed against the RNA component of human telomerase (hTR) was designed and synthesized to serve as a telomerase inhibitor. An in vitro transcription plasmid and a eukaryotic expression plasmid containing teloRZ gene were constructed. In vitro cleavage reaction was carried out by mixing the ribozyme RNA with DIG-labeled-hTR in different reaction conditions. Cleavage bands were detected by digoxin chemilumines- cent assay. The eukaryotic expression plasmid was inducted into HeLa cells by lipofectamine; the telomerase activities and bio-characteristics of HeLa cells were detected continuously.

RESULTS

teloRZ showed a specific cleavage activity against the telomerase RNA component used as template. The in vitro cleavage ratio reached about 60%. The telomerase activities of cells expressing teloRZ dropped to eight times; the doubling times became longer and apoptosis ratios became higher with increasing population doublings (PDS); at 19-20 PDS 95% cells showed apoptosis.

CONCLUSION

These findings support the potential use of this ribozyme against immortalized cancer cells.

[Expression of multidrug resistance-associated protein (MRP) and lung resistance protein (LRP) in human rectal carcinomas and its clinical significance]

OBJECTIVE

To investigate the expression and clinical significance of multidrug resistance-associated protein(MRP) and lung resistance protein(LRP) in rectal carcinoma.

METHODS

Fiftyseven paraffin embeded primary rectal carcinoma specimens were examined by immunohistochemical staining.

RESULTS

Of the 57 tumour specimens examined, 28(49.1%) and 24(42.1%) were positively immunostaned for MRP and LRP, respectively. Co-expression of the two proteins was observed in 10(17.5%) specimens. Positive immunostaning of either of the two proteins was not correlated with cell differentiation and Dukes stage (P > 0.05). Patients with MRP-positive tumours had shorter survival than MRP-negative patients (P < 0.05). No such correlation was found for LRP expression, nor was found between MRP and LRP expression.

CONCLUSION

Positive MRP expression in rectal carcinoma appears to be an independant factor of prognostic significance. To examine its expression may help guide rational comprehensive therapy of rectal carcinoma.

Polymeric gadolinium chelate magnetic resonance imaging contrast agents: design, synthesis, and properties

We have synthesized and evaluated five series of polymeric gadolinium chelates which are of interest as potential MRI blood pool contrast agents. The polymers were designed so that important physical properties including molecular weight, relaxivity, metal content, viscosity, and chelate stability could be varied. We have shown that, by selecting polymers of the appropriate MW, extended blood pool retention can be achieved. In addition, relaxivity can be manipulated by changing the polymer rigidity, metal content affected by monomer selection, viscosity by polymer shape, and chelate stability by chelator selection.

[Cross reaction of Trichinella spiralis larva antigens with sera of schistosomiasis japonica]

Cross reactions of T. spiralis muscular larva antigens (TsMLA) against several sera from patients with other parasitic diseases by ELIB (enzyme-linked immunoblotting technique) were studied. The proteins of 31-100 KDa were recognized by sera of two cases of acute schistosomiasis, while proteins of 44/45, 51/53, 62/64 and 100 KDa were recognized by sera of 11 cases of chronic schistosomiasis. The proteins of 60 KDa showed varied cross reactions against sera of five kinds of patients with other parasitic diseases (filariasis, hookworm diseases, paragonimiasis, ascariasis and clonorchiasis). Only the proteins of 45 KDa were recognized by six of fifteen cases of normal human sera. All of > 29 KDa proteins were recognized by sera of rabbit infected by T. spiralis. It is suggested that there were many antigens in Trichinellen muscular larva which shared in common with several other parasites. The cross reactions of TsMLA against Schistosoma japonicum may be differentiated on the positive reaction bands of 44/45, 51/53, 62/64 and 100 KDa proteins which was specific to the chronic schistosomiasis using the TsMLA by means of ELIB.

Mechanisms of growth stimulation by suramin in non-small-cell lung cancer cell lines

PURPOSE

Suramin, a polysulfonated naphthylurea, has been shown to be effective in the treatment of several cancers. We have reported that suramin, at dose concentrations higher than 140 microM, exerts growth-stimulatory effects in several non-small-cell lung cancer (NSCLC) cell lines. The purpose of this study was to examine the mechanisms by which suramin exerts this growth-stimulatory effect in NSCLC cells.

METHODS

NCI-H596 cells were treated with agarose-immobilized suramin, directly or by addition on cell culture inserts, after which growth was determined by [3H]thymidine incorporation. PPADS, a specific purinergic receptor antagonist, was used to determine whether suramin acts via purinergic receptors. The effect of suramin on epidermal growth factor receptor (EGFR) was determined by analyzing receptor phosphorylation and dimerization. XAMR 0721, a suramin analogue containing only one of the two polysulfonated arms, was also analyzed for its effects on growth and EGFR activation.

RESULTS

Agarose-immobilized suramin stimulated NCI-H596 cell growth, but only when added directly to the cells. When the suramin-conjugated beads were added to the cells on cell culture inserts, which preclude an interaction with the cell surface but allow interaction with the culture medium, there was no effect on proliferation. PPADS had no effect on the growth stimulation by suramin; however suramin treatment resulted in rapid phosphorylation and dimerization of EGFR. Treatment with XAMR 0721 did not affect growth or tyrosine phosphorylation and dimerization of EGFR.

CONCLUSIONS

Suramin need not enter NCI-H596 cells to exert its growth-stimulatory effect, nor is this effect mediated by an interaction with soluble growth factors. Rather, it appears that suramin acts via an interaction with EGFR, but not with purinergic receptors.

Interaction of tissue transglutaminase with nuclear transport protein importin-alpha3

Tissue transglutaminase is a multifunctional enzyme which has been involved in the regulation of cell growth, differentiation, and apoptosis. Recently, nuclear localization of tTG has been reported indicating the potential of active nuclear transport. In this study we use the yeast two-hybrid assay and co-immunoprecipitation to show that tTG interacts with the nuclear transport protein importin-alpha3. Using electron microscopy we demonstrate that nuclear expression of tTG in a non-small cell lung cancer cell line is induced by retinoic acid (RA). These data suggest that importin-alpha3 could mediate active nuclear transport of tTG which may be important for the regulation of critical cellular processes.

Detection and sequence analysis of borna disease virus p24 RNA from peripheral blood mononuclear cells of patients with mood disorders or schizophrenia and of blood donors

Borna disease virus (BDV) p24 RNA was detected in the peripheral blood mononuclear cells (PBMCs) of psychiatric patients and blood donors by nested reverse transcriptase PCR (RT-PCR). The prevalences of BDV p24 RNA in patients with mood disorders (4%) and schizophrenia (4%) were not significantly different from that in blood donors (2%). This finding was inconsistent with previous reports that showed either a high prevalence or absence of BDV p24 RNA in patients with psychiatric disorders. The differences in BDV p24 RNA prevalence in these studies may be due to differences in the criteria for positivity, the number of PBMCs used for RNA extraction, or the amount of RNA tested for nested RT-PCR or to laboratory contamination. Sequence analysis of BDV p24 RNA from the PBMCs of patients and blood donors showed a high nucleotide sequence conservation but definite nucleotide mutations compared with horse BDV p24 RNA sequences. In comparison with human BDV p24 RNA sequences previously reported from Japan and Germany, there were several positions with silent nucleotide mutations among these clones.

Effects of anti-IL-4 receptor monoclonal antibody on in vitro T cell cytokine levels: IL-4 production by T cells from non-atopic donors

IL-4 is a pleiotropic cytokine which is involved in the development of atopic diseases. Only limited data exist on IL-4 production in humans, and the relative contribution to atopy of either unbalanced IL-4 production, or increased IL-4-responsiveness of target cells, is still unknown. The use of a MoAb to the IL-4 receptor alpha-chain (IL-4Ralpha) enabled us to demonstrate that IL-4 production in vitro is usually underestimated, due to in vitro consumption, even in cultures of purified T cells. When IL-4 consumption was blocked, it became evident that CD80 and CD86 both provide effective costimulatory signals for high IL-4 production. Moreover, we found that even stimulation with a soluble antigen (tetanus toxoid) induces IL-4 production by T cells from healthy non-atopic donors. Both sets of data imply that IL-4 is not required for IL-4 production by memory and/or effector T cells. Our data further show that endogenous IL-4 activity modulates IL-10 and interferon-gamma production by T cells in opposite directions. The use of this receptor-blocking antibody will thus be helpful for in vitro studies on IL-4 regulation. Consumption of IL-4 by different cell types during in vitro cultures might have interfered with previous attempts to quantify IL-4 production by human T cells.

[Observations on rat's muscle at various postmortem intervals by scanning electron microscopy]

The aim of this study was to observe the morphological changes of muscle in the process of rigor mortis. The quadriceps of 40 rats at various postmortem intervals were observed under the scanning electron microscope (SEM) and the light microscope by phosphtungstic acid-haematoxylin staining. The results showed that the striations of muscle were blurred within 4 hours, but they became apparent from 6 hours to 24 hours after death. The authors suggest that this phenomenon be associated with the increased resistance of muscle against the postmortal changes. The observations by scanning electron microscopy and light microscopy have revealed that the muscles do contract in the process of rigor mortis because the distance between two Z lines shortens and the I band narrows, compared with those in anaesthetised animals. The basic biochemical process for the formation of rigor mortis is the same as that of muscle contraction except that the former happens postmortem and the latter antemortem.

[Investigation of an Legionnaires' disease outbreak associated with contaminated air-conditioning]

An outbreak of upper respiratory infection (influenza-like syndrome) took place among the staff members of a large office building in Beijing, June, 1997. To understand the cause of the outbreak, with a case-control study with serological antibodies detection against serogroup 1 to 14 of Legionnaires' disease bacteria (LDB) and bacteriological test and culture on samples collected from the air-conditioning system of the office building was performed. The findings showed that the attack rates of tonsillitis and upper respiratory infection were 61.86% and 34.62% respectively. The relation was statistically significant between the symptoms of fever and tonsillitis in the cases (chi 2 = 77.88, P < 0.01). The positive rates of LDB antibodies on serogroups 9, 10, 12, 14 were 45.94% in the cases of upper respiratory infection and 3/15, 6/17, 0/15, 1/16 respectively in the four controls groups. Condensied water samples from an air-conditioning system showed that Legionella Pneumophila was positive. Evidence showed that it was an outbreak resulting from LDB serogroup 9 and 12, accompanied by upper respiratory infection related to air-conditioning system contaminated by LDB. This was the first report Lp infection associated with an air-conditioning system in China.

Identification of a membrane-associated inhibitor(s) of epidermal growth factor-induced signal transducer and activator of transcription activation

Many growth factors, including epidermal growth factor (EGF), can activate the signal transducer and activator of transcription (STAT) signaling pathway. Here, we demonstrate that STAT activation by EGF treatment is conditional. EGF activates STAT1 and STAT3 in A431 but not in HeLa and PC12 cells. Using a reconstituted in vitro STAT activation system, we have identified and partially purified a potential inhibitor (s) that is membrane-associated and can block STAT activation induced by EGF in vitro. However, this inhibitor has no effect on STAT complexes after they are formed. We have further shown that this inhibitor(s) also exists in many other cancer cell lines, suggesting that blocking the STAT activation during growth factor signal transduction may play a significant role in the development of many kinds of cancers.

A brief history of diagnostic cytology

Being a discipline specialized for diagnosis of tumors, diagnostic cytology has a history of over 100 years. By exploring the origin, development and its formative process, valuable and special information which are helpful to the general investigation of tumor cases and screening of such patients can be provided.

Cloning of a Sphingomonas paucimobilis SYK-6 gene encoding a novel oxygenase that cleaves lignin-related biphenyl and characterization of the enzyme

Sphingomonas paucimobilis SYK-6 transforms 2,2'-dihydroxy-3,3'-dimethoxy-5,5'-dicarboxybiphenyl (DDVA), a lignin-related biphenyl compound, to 5-carboxyvanillic acid via 2,2',3-trihydroxy-3'-methoxy-5,5'-dicarboxybiphenyl (OH-DDVA) as an intermediate (15). The ring fission of OH-DDVA is an essential step in the DDVA degradative pathway. A 15-kb EcoRI fragment isolated from the cosmid library complemented the growth deficiency of a mutant on OH-DDVA. Subcloning and deletion analysis showed that a 1.4-kb DNA fragment included the gene responsible for the ring fission of OH-DDVA. An open reading frame encoding 334 amino acids was identified and designated ligZ. The deduced amino acid sequence of LigZ had 18 to 21% identity with the class III extradiol dioxygenase family, including the beta subunit (LigB) of protocatechuate 4,5-dioxygenase of SYK-6 (Y. Noda, S. Nishikawa, K.-I. Shiozuka, H. Kadokura, H. Nakajima, K. Yano, Y. Katayama, N. Morohoshi, T. Haraguchi, and M. Yamasaki, J. Bacteriol. 172:2704-2709, 1990), catechol 2,3-dioxygenase I (MpcI) of Alcaligenes eutrophus JMP222 (M. Kabisch and P. Fortnagel, Nucleic Acids Res. 18:3405-3406, 1990), the catalytic subunit of the meta-cleavage enzyme (CarBb) for 2'-aminobiphenyl-2,3-diol from Pseudomonas sp. strain CA10 (S. I. Sato, N. Ouchiyama, T. Kimura, H. Nojiri, H. Yamane, and T. Omori, J. Bacteriol. 179:4841-4849, 1997), and 2,3-dihydroxyphenylpropionate 1,2-dioxygenase (MhpB) of Escherichia coli (E. L. Spence, M. Kawamukai, J. Sanvoisin, H. Braven, and T. D. H. Bugg, J. Bacteriol. 178:5249-5256, 1996). The ring fission product formed from OH-DDVA by LigZ developed a yellow color with an absorption maximum at 455 nm, suggesting meta cleavage. Thus, LigZ was concluded to be a ring cleavage extradiol dioxygenase. LigZ activity was detected only for OH-DDVA and 2,2',3,3'-tetrahydroxy-5,5'-dicarboxybiphenyl and was dependent on the ferrous ion.

[Morphologic changes of red blood cells in various conditions under scanning electron microscope]

To study the changes of RBC in various conditions, blood clots elapsed 6 days in water and air and bloodstains stored in variant time were observed under Scanning Electron Microscope (SEM). The results showed that the morphology of RBC elapsed 6 days in water and air seemed to retain their integrity. They were measured 5, 48-5, 88 microns in diameter, whereas the RBC in the bloodstains stored 14 years were obviously disfigured and some appeared membrane cracking. However, the structure of RBC membrane was well recognized under the SEM. The morphological changes under the SEM and the forensic significance of the RBC were discussed.

Smoking and the development of Warthin's tumour of the parotid gland

The smoking history was surveyed in 160 consecutive patients with Warthin's tumour of the parotid gland in order to investigate the relationship between smoking and the development of this tumour. Two hundred cases of middle-aged or elderly normal persons and 163 consecutive patients with pleomorphic adenoma in the parotid gland served as controls. The percentage of smoking in patients with Warthin's tumour (96.3%) was much higher than that of middle-aged or elderly normal persons (25.5%) and in patients with pleomorphic adenoma (26.4%). Moreover, the amount of smoking was greater and the smoking history was longer in patients with Warthin's tumour. When the male and female patients were analysed respectively, the same result was shown. This case-control study suggests that smoking may be one of the aetiologic factors associated with the development of Warthin's tumour.

Cyclosporin A increases IFN-gamma production by T cells when co-stimulated through CD28

Despite its calcineurin-inhibiting properties, cyclosporin A (CsA) can not inhibit IL-2 production when T cells are co-stimulated by CD80/CD86 on the antigen-presenting cells. We studied the in vitro effect of CsA on IFN-gamma production. Anti-CD3 monoclonal antibody (mAb) was used as the primary stimulus for activation of purified human T cells. A stimulating anti-CD28 mAb, or CD80 or CD86 on stably transfected P815 cells, provided the co-stimulatory signal. IL-2 production was hardly affected by CsA under these stimulating conditions, while IFN-gamma (at the protein and mRNA level) was markedly stimulated by CsA. The use of anti-CD3 or phorbol 12-myristate 13-acetate with ionomycin as the primary stimulus, together with costimulation through either CD28 or CD2 using transfectants with the appropriate ligands, allowed us to demonstrate that the resistance of IFN-gamma production to inhibition by CsA required both CD3 and CD28 triggering. Inhibition of IL-10 production, and to a lesser degree of IL-4 production, by CD4+ cells was responsible for the enhancement of IFN-gamma production in the presence of CsA. In conclusion, IFN-gamma production by CD28-co-stimulated CD4+ T cells is resistant to inhibition by CsA and can even be facilitated by CsA as a result of removing a negative regulatory signal which is mainly IL-10 mediated. This finding might have implications for immunosuppressive strategies based upon the use of CsA.

Serum deprivation-induced apoptosis in cultured porcine granulosa cells is characterized by increased expression of p53 protein, Fas antigen and Fas ligand and by decreased expression of PCNA

Although serum deprivation induces apoptosis in several cell lines, biochemical characterization of the apoptosis in primary granulosa cells (GCs) induced by serum deprivation has rarely been reported. In the present study, GCs from small follicles of porcine ovaries were precultured under a serum-containing condition for seven days, then stepped down to a serum-free condition and cultured for the subsequent two days. GCs were subjected to DNA fragmentation and immunoblot analyses. Data indicated that serum deprivation induced GC apoptosis characterized by DNA laddering, which was associated with decreased expression of proliferating cell nuclear antigen (PCNA) and increased expression of p53 protein, Fas antigen and Fas ligand. Serum deprivation also resulted in an increase in a 115 kDa protein expression despite no detectable expression of a 66 kDa c-myc protein. This suggests that serum removal from primary GCs may activate multiple apoptotic pathways such as a p53-associated pathway and a Fas-Fas ligand pathway.

Pertussis toxin-sensitive G proteins influence nitric oxide synthase III activity and protein levels in rat heart

Inhibitory G protein activity (Gi) and nitric oxide (NO) modulate muscarinic-cholinergic (MC) inhibition of cardiac beta-adrenergic inotropic responses. We hypothesized that Gi mediates MC-NO synthase (NOS) signal transduction. Isoproterenol (0.2-0.8 microg/min) and acetylcholine (1 microM) were administered to isolated perfused rat hearts pretreated with saline (controls; n = 8) or pertussis toxin (PT; 30 microg/kg intraperitoneally 3 d before study; n = 20). PT abrogated in vitro ADP-ribosylation of Gi protein alpha subunit(s) indicating near-total decrease in Gi protein function. Isoproterenol increased peak +dP/dt in both control (peak isoproterenol effect: +2, 589+/-293 mmHg/s, P < 0.0001) and PT hearts (+3,879+/-474 mmHg/s, P < 0.0001). Acetylcholine reversed isoproterenol inotropy in controls (108+/-21% reduction of +dP/dt response, P = 0.001), but had no effect in PT hearts. In controls, NG-monomethyl-L-arginine (100 microM) reduced basal +dP/dt, augmented isoproterenol +dP/dt (peak effect: +4,634+/-690 mmHg/s, P < 0.0001), and reduced the MC inhibitory effect to 69+/-8% (P < 0.03 vs. baseline). L-arginine (100 M) had no effect in controls but in PT hearts decreased basal +dP/dt by 1, 426+/-456 mmHg/s (P < 0.005), downward-shifted the isoproterenol concentration-effect curve, and produced a small MC inhibitory effect (27+/-4% reduction, P < 0.05). This enhanced response to NO substrate was associated with increased NOS III protein abundance, and a three- to fivefold increase in in vitro calcium-dependent NOS activity. Neomycin (1 microM) inhibition of phospholipase C did not reverse L-arginine enhancement of MC inhibitory effects. These data support a primary role for Gi in MC receptor signal transduction with NOS in rat heart, and demonstrate regulatory linkage between Gi and NOS III protein levels.

[Analysis of the major components in cannabis by capillary gas chromatography]

A capillary GC method for the simultaneous determination of cannabidiol (CBD), tetrahydrocannabinol (THC), and cannabinol (CBN) in cannabis is described. The major components in cannabis were extracted with chloroform. After being concentrated by evaporation, the residue was dissolved in methanol. The resulting solution was used for analysis. The conditions for determination were: FID detector, HP-5 capillary column, 10 m x 0.53 mm x 2.65 microns film, column temperature 220 degrees C. The recoveries of the three major components were 97.3%-104.0%(CBD), 97.3%-106.6%(THC) and 95.3%-102.4% (CBN). The coefficients of variation are less than 3%. The limit of detection for the three components was 0.2 mg/L, and their linearity was in the range of 20-120 mg/L. Identification of each component was achieved by comparison of retention times with the standards. This method has the advantages of simplicity, rapidity, sensitivity and accuracy.

[Polymerase chain reaction associated with dig-labelled DNA hybridization of mip gene to identify new isolated Legionella pneumophila strains]

OBJECTIVE

By testing mip gene, one highly conservative virulence gene of Legionella pneumophila (Lp), as targets of polymerase chain reaction (PCR) and Digoxin-labelled probe hybridization to establish a rapid, specific and sensitive gene analysis method that can identify new isolated suspected bacteria strains as Lp.

METHOD

Abstracting all the CDC reference Lp strains' and none-Lp Legionella strains' DNA, as well as the domestic isolated Lp strains' and some non-Legionella control bacteria's DNA as templates, then were processed. All the positive PCR products(if no PCR amplicons were available, the original whole DNA should be detected) were hybridized with Digoxingen-labelled mip gene probe in dot-blot procedure.

RESULT

All the tested Lp strains had positive PCR and hybridization results, at the same time, all none-Legionella bacteria and none-Lp Legionella strains got negative results. 6 of 26 isolates were identified as Lp strains by this method.

CONCLUSION

Such a Lp strain identification procedure shows high specificity and sensitivity (nearly 100%, in this study), and mean-while can be completed in a relative short time. Surely, this method can be largely available and has a potential value in diagnosis of clinical Legionellosis cases and pursuing the pathogen during Legionnaires' disease outbreaks.

IL-12 up-regulates CD40 ligand (CD154) expression on human T cells

IL-12 is a heterodimeric cytokine produced by APC that promotes the development of CD4+ Th1 cells and their IFN-gamma production after TCR/CD3 triggering. We here investigated the capacity of IL-12 to modify the expression on T cells of CD40 ligand (CD40L or CD154), a molecule transiently expressed on activated T cells and known to be of utmost importance for cognate interaction with B cells and for activation of dendritic cells and macrophages. Our data demonstrate that IL-12 up-regulates CD40L expression on anti-CD3-activated human peripheral blood T cells. For optimal induction of CD40L, IL-12 synergizes with IL-2 as well as with other costimulatory interactions, such as B7/CD28. The effect of IL-12 was observed at both the protein and the mRNA level. T cells costimulated by IL-12 provided more efficient help for IL-4-dependent B cell proliferation and for IgG production than when activated in the absence of IL-12. This helper activity was blocked by an mAb against CD40L, indicating that the effect of IL-12 on B cells is mediated indirectly through CD40L. The data thus suggest that the effects of IL-12 on cellular and humoral immune responses are partly mediated through CD40L induction.