A 16.6-kilodalton protein in the Cyanobacterium synechocystis sp. PCC 6803 plays a role in the heat shock response

The low molecular weight (LMW) heat shock protein (HSP) gene hsp16.6 was identified and cloned from the unicellular cyanobacterium Synechocystis sp. PCC 6803 through comparisons of genomic sequences and conserved gene sequences of the LMW HSPs. Hsp16.6 was isolated using PCR and cloned into the pGEMT plasmid. Hsp16.6 showed a significant increase in transcription after heat shock at 42 degreesC that indicated hsp16.6 was a heat shock gene. To determine the role that hsp16.6 plays in the heat shock response, a mutant Synechocystis cell line was generated. Cell growth and oxygen evolution rates of wild type and mutant cells were compared after heat shock. Results showed significantly decreased cell growth rates and a 40% reduction in oxygen evolution rates in mutants after heat shock treatments. These data indicate a protective role for hsp16.6 in the heat shock response.

[Effects of chronic morphine treatment on inositol phosphates contents and PKC activity in mouse brain]

By inducing morphine dependence in mice, changes in inositol phosphate contents, protein kinase C(PKC) activity in brain regions and effect of PKC inhibitor on the development of morphine dependence were investigated. It was found that: (1) IP(inositol phosphate) and IP3 (inositol trisphosphate) contents in striatum, IP in cerebral cortex and total inositol phosphates(IP + IP2 + IP3) in striatum and cerebral cortex were markedly higher than those of the control. But no similar changes in hippocampus and cerebellum were observed. (2) Cytosolic PKC activity was significantly increased in cerebellum and cerebral cortex but decreased in striatum. The membrane PKC activity was apparently enhanced in striatum but decreased in cerebellum and hippocampus. (3) PKC inhibitor was found to prevent the development of morphine dependence. (4) These changes described above were not observed in mice treated with naloxone 30 min prior to daily morphine injection. Our data indicate that the increase of inositol phosphate contents in striatum implied activation of phospholipase C, which might lead to PKC activation. This PKC activation may be involved in the development of morphine dependence.

[Study on cis-acting elements of rat glutathione S-tranferase P1 gene]

OBJECTIVE

To investigate the cis-acting regulatory DNA elements in 3.0 kb 5' flanking upstream region of rat glutathione S-tranferase (rGSTP1) gene.

METHODS

Using exonuclease III (Exo III) and S1 nuclease, a series of deletions were made in the 3.0 kb region, then fused into highly sensitive luciferase reporter vector. The deleted mutants were transfected into HeLa cells. Luciferase activities of the transfected cell lysates were assayed.

RESULTS

Deleted from -2.9 kb to -2.3 kb, luciferase activity had dropped about 67% (P < 0.05). The element between -2.5 kb and -2.2 kb could increase gene expression activity regardless of orientation and position. Further deleted from -1.8 kb to -1.3 kb, luciferase activity increased about three times (P < 0.05).

CONCLUSIONS

There are enhancer element between -2.5 kb and -2.2 kb and a negative regulatory sequence between -1.8 kb and -1.3 kb in the upstream region of rGSTP1 gene.

Construction of human insulin gene expression recombinant and its effect on blood glucose of diabetic rats

OBJECTIVE

To study the effect of human insulin gene modified fibroblasts on blood glucose in diabetic rats.

METHODS

An expression vector containing human insulin gene was constructed by recombinant DNA technique and introduced into fibroblast Ltk- cells by lipofectin-mediated DNA transfection. Following G418 screening, the survived cells were selected and enriched. Finally a cell line, PRI-12 was generated for the highest insulin production. Then, these cells were injected into streptozocin (STZ)-induced diabetic rats.

RESULTS

Insulin DNA transfected Ltk- cells were able to express insulin at a high level in a long-term culture. Furthermore, these Ltk- transfectants could decrease blood glucose significantly (P < 0.01) and obviously increase the body weight (P < 0.01) when they were injected into STZ-induced diabetic rats.

CONCLUSIONS

These results suggest that the cell lines transfected insulin gene could secrete insulin and execute effect on diabetic rats. The study provides support for the view that somatic cell gene therapy offers a potential approach to delivery insulin into diabetes mellitus.

Color correction of the video image obtained by angioscope

In this article, a simple color correction method for the color reproduction of image obtained by angioscope is reported. We present the method to obtain the matrices theoretically and experimentally, respectively. For the angioscope system, we suggest two matrices: an average color correction matrix A and a blood vessel color correction matrix A'. Using the two matrices, the images of several color samples captured by an angioscope are processed, and their reproduced colors are evaluated. With this method, the discrimination ability of the angioscope will be improved dramatically. © 1998 Society of Photo-Optical Instrumentation Engineers.

Antinociception produced by microinjection of morphine in the rat periaqueductal gray is enhanced in the foot, but not the tail, by intrathecal injection of alpha1-adrenoceptor antagonists

Antinociception produced by microinjection of morphine in the ventrolateral periaqueductal gray is mediated in part by alpha2-adrenoceptors in the spinal cord dorsal horn. However, several recent reports demonstrate that microinjection of morphine in the ventrolateral periaqueductal gray inhibits nociceptive responses to noxious heating of the tail by activating descending neuronal systems that are different from those that inhibit the nociceptive responses to noxious heating of the feet. More specifically, alpha2-adrenoceptors appear to mediate the antinociception produced by morphine using the tail-flick test, but not that using the foot-withdrawal or hot-plate tests. The present study extended these findings and determined the role of alpha1-adrenoceptors in mediating the antinociceptive effects of morphine microinjected into the ventrolateral periaqueductal gray using both the foot-withdrawal and the tail-flick responses to noxious radiant heating in lightly anesthetized rats. Intrathecal injection of selective antagonists was used to determine whether the antinociceptive effects of morphine were modulated by alpha1-adrenoceptors. Injection of the selective alpha1-adrenoceptor antagonists prazosin or WB4101 potentiated the increase in the foot-withdrawal response latency produced by microinjection of morphine in the ventrolateral periaqueductal gray. In contrast, either prazosin or WB4101 partially reversed the increase in the tail-flick response latency produced by morphine. These results indicate that microinjection of morphine in the ventrolateral periaqueductal gray modulates nociceptive responses to noxious heating of the feet by activating descending neuronal systems that are different from those that inhibit the nociceptive responses to noxious heating of the tail. More specifically, alpha1-adrenoceptors mediate a pro-nociceptive action of morphine using the foot-withdrawal response, but in contrast, alpha1-adrenoceptors appear to mediate part of the antinociceptive effect of morphine determined using the tail-flick test.

Antimalarial activity of radicicol, heptelidic acid and other fungal metabolites

In the course of our screening program for artemisinin-like antimalarial compounds from microorganisms, seven fungal metabolites such as radicicol and heptelidic acid were identified as active compounds. Some of them exhibited antimalarial activity in vitro against the human malaria parasite Plasmodium falciparum to the extent of approximately 1/10 as potent as artemisinin. Radicicol was moderately active in vivo against Plasmodium berghei in mice.

Tumor necrosis factor alpha, interleukin-6, interleukin-8, and interferon alpha in children with viral hepatitis

To investigate the cellular immunological changes in children with viral hepatitis, interleukin 6 (IL-6), interleukin 8 (IL-8), interferon alpha (IFN alpha), and tumor necrosis factor alpha (TNF alpha) in supernatant of cultured peripheral blood mononuclear cells (PBMCs) of 49 children with hepatitis A, B or C were measured. The levels of IL-6, IL-8, TNF alpha in PBMCs of the 3 viral hepatitis groups were increased and the level of IFN alpha decreased as compared with those of normal control group. But there were no significant differences among the 3 viral hepatitis groups. It was concluded that cellular immunological disorders were related to the onset and the induced damage of the viral hepatitis in children.

Two new components of the aspochalasins produced by Aspergillus sp

Aspergillus sp. FO-4282 was found to produce two new components of the aspochalasins. Their structures were determined by spectroscopic analyses.

Opiate receptors in the periaqueductal gray mediate analgesic effect of nitrous oxide in rats

The site of action and the pathways which are activated by nitrous oxide (N2O) to produce an analgesic effect are not well defined. Experiments were designed to determine whether N2O produces analgesia by activating opiate receptors or alpha2-adrenoceptors in periaqueductal gray. The analgesic effect of N2O was determined using the tail flick response to noxious radiant heat in lightly anesthetized rats. Different antagonists were bilaterally microinjected into ventrolateral periaqueductal gray to determine whether the analgesic effect produced by N2O was reversed. The increase in the tail flick latencies produced by N2O was reversed by bilateral microinjection into the ventrolateral part of periaqueductal gray with the opiate receptor antagonist naloxone 2.5 microg/0.5 microl, but not with the alpha2-adrenoceptors antagonist yohimbine 1.5 microg/0.5 microl. These results indicate that the N2O analgesic effect is mediated by activation of opiate receptors, but not alpha2-adrenoceptors, in the periaqueductal gray. Combined with the previous experiments that the N2O analgesic effect is reversed by intrathecal injection of an alpha2-adrenoceptor antagonist but not by an opiate receptor antagonist, it seems likely that N2O causes activation of the opiate receptors in the periaqueductal gray, which in turn activate the noradrenergic descending pathways to the spinal cord to produce the analgesic effect.

[Determination of gamma-aminobutyric acid and glutamic acid in human cerebrospinal fluid by high performance liquid chromatography]

Gamma-aminobutyric acid (Gaba) and glutamic acid (Glu) are believed to be the major neurotransmitter. Levels in cerebrospinal fluid (CSF) may reflect their metabolism in various neurotic and psychiatric diseases. Measurements of Gaba and Glu in body fluids will help to elucidate their metabolic role and diagnostic value. In the present work, the concentrations of glutamic acid and gamma-aminobutyric acid in human cerebrospinal fluid were determined by reversed-phase high performance liquid chromatography using pre-column derivatized with dansyl chloride and UV detection at 254 nm. The mobile phase was A:CH3OH and B: THF/CH3OH/0.05 mol/L NaAc (pH 6.2) (5/75/420, V/V) with gradient elution. The flow rate was 1 mL/min. CSF samples were deproteinizated with methanol. After centrifugation at 15000 r/min for 10 min, the supernatant was introduced into a screw-capped vial and evaporated to near dryness at 80 degrees C. Derivatization was carried out by the addition of 250 microL of bicarbonate solution (pH 9.8) and 250 microL of dansyl chloride solution (4 g/L) followed by heating at 40 degrees C water bath for 30 min. Extraction was performed with 300 microL of ethyl acetate and the organic layer separated was dried at room temperature under nitrogen. The dry residue was dissolved and injected into the HPLC system. The linear range of the method was 5-1000 micromol/L (r = 0.9988) for Glu and 1-600 micromol/L (r = 0.9984) for Gaba. The lower limit of detection were 0.002 micromol/L and 0.001 micromol/L respectively. The recoveries were 96.9%-98.8% and 97.5%-98.8% and the coefficients of variation of peak height measurements were 2.2%-3.4% and 3.8%-5.6% respectivery. The method enables a simple, rapid and reproducible quantification of Glu and Gaba neurotransmitter.

[Experimental studies on somatic gene therapy for diabetes. I. Structuring of recombinant from human insulin gene and ammalian expression vector PRC/CMV]

To develop a model somatic gene therapy system for diabetes, we constructed a human insulin expression vector in non B cells. As the first step, an insulin cDNA fragment of 260 bp, generated by a complet digestion of PBCA with EcoR I and BamH I, was inserted into the EcoR I/BamH I site of plasmid PBS.SK by ligation of cohevise-ended DNA to construct transition plasmid PBS.INS. Then the plasmid PBS.INS was completly digested by Hind III and Xbal I. The small DNA fragment containing insulin cDNA gene was subcloned to the expression plasmid PRC/CMV to form recombinant PRC/CMV.INS.

Detection of Duffy antigen in the plasma membranes and caveolae of vascular endothelial and epithelial cells of nonerythroid organs

The nonerythroid expression of the Duffy blood group protein (gp-Fy) was confined to certain cell types. Immunocytochemistry studies of the kidney showed gp-Fy in the endothelium of glomeruli, peritubular capillaries, vasa recta, and the principal cells (epithelial) of collecting ducts. Gp-Fy was also produced in the endothelial cells of large venules and epithelial cells (type-I) of pulmonary alveoli. In the thyroid, only the endothelial cells of capillaries produced gp-Fy. In the spleen, the endothelial cells of capillaries, high endothelial venule, and sinusoids produced abundant gp-Fy. Ultrastructural studies showed that apical and basolateral plasma membrane domains, including caveolae, had gp-Fy. Immunoblot analysis showed substantially less gp-Fy in nonerythroid cells than in erythrocytes. Moreover, the analyzed nonerythroid organs of Duffy-negative individuals did not produce more gp-Fy to compensate for the lack of this protein in their erythrocytes. The nucleotide sequence and the size of kidney mRNA from a Duffy-positive individual were the same as that of bone marrow. It is assumed, therefore, that nonerythroid Duffy protein is the product of the same gene as that of bone marrow. This notion is reinforced by the fact that nonerythroid and erythroid gp-Fy have the same antigenic domains.

Immune bioactivity in shellfish toward serum-free cultured human cell lines

The biologically functional effect of eight kinds of hot-water extracts of shellfish on cultured human cell lines was examined in a serum-free medium model. Meretrix lusoria and Sinonovacula constricta extracts enhanced IgM secretion of both hybridoma HB4C5 and SI102 cells when cultured with the respective extracts. The purified principle exhibited remarked activity in the adsorbed fraction in hydroxyapatite and Concanavalin A columns. The extracts of Corbicula fluminea, Crassostreas gigas, Meretrix lusoria, Anadara granosa, and Sinonovacula constricta enhanced in nitroblue tetrazolium (NBT)-reducing ability of macrophage U-M cells. Meretrix lusoria, Anadara granosa, and Sinonovacula constricta were specifically cytotoxic to both cultures of MCF-7 breast cancer cells and HuH-6KK hepatoblastoma. These findings imply that the extracts of shellfish that were examined exhibited a differential effect on immune cells and tumor cells.

[Construction of recombinant glutathione S-transferase pi cDNA and retrovirus vector]

In order to study effect of expression of glutathione S-transferase pi gene on transformation induced by chemical Carcinogens in cellular experiments and explore possibility of gene prevention of tumor, as the first step, we have constructed recombinant glutathione S-transferase pi cDNA and retrovirus vector pXT1.

Spinal cholinergic and monoamine receptors mediate the antinociceptive effect of morphine microinjected in the periaqueductal gray on the rat tail, but not the feet

The antinociceptive effects of morphine (5 micrograms) microinjected into the ventrolateral periaqueductal gray were determined using both the tail flick and the foot withdrawal responses to noxious radiant heating in lightly anesthetized rats. Intrathecal injection of appropriate antagonists was used to determine whether the antinociceptive effects of morphine were mediated by alpha 2-noradrenergic, serotonergic, opioid, or cholinergic muscarinic receptors. The increase in the foot withdrawal response latency produced by microinjection of morphine in the ventrolateral periaqueductal gray was reversed by intrathecal injection of the cholinergic muscarinic receptor antagonist atropine, but was not affected by the alpha 2-adrenoceptor antagonist yohimbine, the serotonergic receptor antagonist methysergide, or the opioid receptor antagonist naloxone. In contrast, the increase in the tail flick response latency produced by morphine was reduced by either yohimbine, methysergide or atropine. These results indicate that microinjection of morphine in the ventrolateral periaqueductal gray inhibits nociceptive responses to noxious heating of the tail by activating descending neuronal systems that are different from those that inhibits the nociceptive responses to noxious heating of the feet. More specifically, serotonergic, muscarinic cholinergic and alpha 2-noradrenergic receptors appear to mediate the antinociception produced by morphine using the tail flick test. In contrast, muscarinic cholinergic, but not monoamine receptors appear to mediate the antinociceptive effects of morphine using the foot withdrawal response.

Influence of temperature on the retention behaviour of proteins in cation-exchange chromatography

The chromatographic behaviour of several amino acid derivatives, peptides and proteins has been investigated with the so called "tentacle-type" LiChrospher-100 SO3- adsorbent and an analogous poly(2-sulphoethylaspartamide) cation-exchange adsorbent, PolySulphoethyl A. In particular, the dependences of the retention properties of a range of biosolutes on temperature and the chromatographic residence time were evaluated with the objective of gaining further insight into the influence of ligand type and flexibility and the role of solute conformation on the chromatographic behaviour of proteins with these two strong cation-exchange chromatographic adsorbents. The results indicate that significant differences in the chromatographic retention behavior between proteins and low-molecular-mass solutes occur as a function of temperature and the type of co- and counter ions present in the mobile phase with both adsorbents. Moreover, the dependences of the Zc and log Kc values on temperature for most of the proteins examined exhibited significant changes in magnitude between 4 and 75 degrees C, whilst no equivalent changes were evident for low-molecular-mass solutes. With the "tentacle-type" LiChrospher-1000 SO3- adsorbent at higher temperatures, e.g., at 75 degrees C, most of the proteins could still be eluted although several exhibited very large increases in their retention parameters. With the PolySulphoethyl A adsorbent, on the other hand, none of the proteins examined were eluted at 75 degrees C. The results moreover indicate that hydrophobic interactions play an increasingly important role in protein retention with both types of ion-exchange adsorbents at higher temperatures, but are more dominant with the PolySulphoethyl A ligand. In general, the Zc values for the proteins with the "tentacle-type" LiChrospher-1000 SO3- adsorbent were greater than those obtained with the PolySulphoethyl A adsorbent, suggesting that the "tentacular" ligands present on this strong cation-exchange adsorbent interact with protein molecules through larger contact areas. Collectively, these investigations provide further support for the concept that the adsorption behaviour of proteins with the "tentacle-type" LiChrospher-1000 SO3- adsorbent and similar types of "tentacular" ligand systems involves a multilayer dissolution mechanism with the protein interacting with a more diffuse or extended Donnan double layer in the ion-exchange environment, resulting in multi-site binding processes.

Heterodimers of placenta growth factor/vascular endothelial growth factor. Endothelial activity, tumor cell expression, and high affinity binding to Flk-1/KDR

Here we show that the Escherichia coli expressed monomers of placenta growth factor (PLGF)129 and vascular endothelial growth factor (VEGF)165 can be re-folded in vitro to form PLGF/VEGF heterodimers. The purified recombinant PLGF/VEGF heterodimers and VEGF homodimers have potent mitogenic and chemotactic effects on endothelial cells. However, PLGF/VEGF heterodimers display 20-50-fold less mitogenic activity than VEGF165 homodimers. In contrast, PLGF129 homodimers have little or no effect in these in vitro assays. We also demonstrate the presence of natural PLGF/VEGF heterodimers in the conditioned media of various human tumor cell lines. While PLGF/VEGF heterodimers bind with high affinity to a soluble Flk-1/KDR receptor, PLGF129 homodimers fail to bind to this receptor. Cross-linking of 125I-ligands to human umbilical vein endothelial cells reveals that PLGF/VEGF heterodimers and VEGF165 homodimers, but not PLGF129 homodimers, form complexes with membrane receptors. VEGF165 homodimers and PLGF/VEGF heterodimers stimulate tyrosine phosphorylation of a 220-kDa protein, the expected size for the KDR receptor in human umbilical vein endothelial cells, whereas PLGF129 homodimers are unable to induce tyrosine phosphorylation of this protein. These data indicate that PLGF may modulate VEGF-induced angiogenesis by the formation of PLGF/VEGF heterodimers in cells producing both factors.

Dependence of cyclin E-CDK2 kinase activity on cell anchorage

Most nonmalignant cells are anchorage-dependent; they require substrate attachment for growth and, in some instances, survival. This requirement is lost on oncogenic transformation. The cyclin E-CDK2 complex, which is required for the G1-S transition of the cell cycle, was activated in late G1 phase in attached human fibroblasts, but not in fibroblasts maintained in suspension. In transformed fibroblasts the complex was active regardless of attachment. The lack of cyclin E-CDK2 activity in suspended cells appeared to result from increased expression of CDK2 inhibitors and a concomitant decrease in phosphorylation of CDK2 on threonine-160. Suppression of cyclin E-CDK2 activity may thus underlie the anchorage dependence of cell growth.

[Proto-oncogene point mutation of c-Ha-ras in bronchogenic carcinoma]

11 bronchogenic carcinoma and 8 corresponding paracarcinoma specimens were detected for activating point mutation in codon 12 of c-Ha-ras gene by Southern blotting hybridization technique. The c-Ha-ras gene was found to be activated by point mutation in codon 12 in 8 of bronchogenic carcinoma and 1 of paracarcinoma tissues. The mutative and unmutative hybrid band was both discovered in 2 of paracarcinoma tissues. Analysis of clinical and pathological features, we conclude that: (1) The point mutation of c-Ha-ras gene codon 12 is found in 77.8% bronchogenic carcinoma among Chinese; (2) At least in part cases, mutation of c-Ha-ras gene codon 12 is not the "initiation" event, but may be a early-stage event in the pathogenesis; (3) No apparent association between the c-Ha-ras gene codon 12 mutation and pathological types, disease stages and history of smoking is present.

[The variable number of tandem repeats in the renin gene of rats and possible significance in hypertension]

The variable number of tandem repeats (VNTR) in the first intron of renin gene for the spontaneously hypertensive rat (SHR), its controls Wistar-Kyoto (WKY), renal hypertensive rat, and Sprague-Dawley rat (SD) were compared by polymerase chain reaction (PCR) method. An analysis of VNTR from WKY, Wistar and SD showed that there are two different renin gene alleles and three genetypes 2.0kb/2.0kb, 2.0kb/1.8kb, 1.8kb/1.8kb. The genetype from renal hypertensive rats is same as those seen in the normal controls. However, compared with the WKY, Wistar and SD genes, a "deletion" of approximately 1.0kb was found in the first intron of the SHR renin gene. Our results strongly suggest that the cause and mechanism of elevated blood pressure is complex, and the molecular basis of the genetic-prone hypertension is existed.

Substrate specificity in short-chain phospholipid analogs at the active site of human synovial phospholipase A2

The substrate specificity at the active site of recombinant human synovial fluid phospholipase A2 (hs-PLA2) was investigated by the preparation of a series of short-chain phospholipid analogs and measurement of their enzymatic hydrolysis at concentrations well below the critical micelle concentration. Substrates used in the study included 1,2-dihexanoylglycerophospholipids, 1,2-bis(alkanoylthio)glycerophospholipids, and 1-O-alkyl-2-(alkanoylthio)phospholipids. Turnover was observed for only a few of the 1,2-dihexanoylglycerophospholipids, and the rate of hydrolysis was very low, near the limit of detection of the assay. In contrast, selected 2-(alkanoylthio)-glycerophospholipids were hydrolyzed by hs-PLA2 at much higher rates at concentrations well below their critical micelle concentration (cmc). Thus, the 1,2-bis(hexanoylthio)glycerophosphatidylmethanol exhibits a k(cat)/K(M) = 1800 L mol-1 s-1. Over the calculated log P (cLogP) range of 3-9, cLogP and log(k(cat)/K(M) were linearly related for compounds with straight-chain sn-1 and sn-2 substituents. At comparable cLogP's, the sn-1 ethers and thioesters were hydrolyzed at comparable rates. A negative charge in the phosphate head group was required for enzyme activity. Unsaturation, aromaticity, and branching in the sn-2 substituent reduce turnover dramatically. The same structural modifications in the sn-1 substituent have less effect on turnover. Certain of these substrates, e.g., 1,2-bis(hexanoylthio)glycerophosphatidylmethanol, may be useful in assaying for active site inhibitors of PLA2. The structure--activity relationships established here for substrates should serve as a reference for the structure--activity relationships of substrate-based inhibitors.