[Susceptibility study on urogenital Chlamydia trachomatis to 19 kinds of antibiotics]

We detected the minimal inhibitory concentrations (MIC) and minimal bacteriocidal concentrations (MBC) of 19 kinds of antibiotics against urogenital chlamydia trachomatis (CT) from sexually transmitted disease (STD) patients. The results were as follows: (1) The mean MICs of tetracycline, doxycycline, minocycline, erythromycin, josamycin, medimycin, lomexacin and ofloxacin were lower than 0.08 microgram/ml. Clindamycin was lightly inhibitant to CT. Steptomycin, cephaloradine, chloramiphonic, metronidazole, ciprofloxacin, sulfamethaxazole and trimethoprim showed no activitis to urogenital CT. (2) The values of the MICs and MBCs of the standard strains were among those of the isolated ones. Another the differences in drug susceptibility of different serovars were observed. (3) The MIC detected method is also discussed.

[Amplification and overexpression of c-erbB2 in human breast cancer]

Quantitative DNA dot blot hybridization and immunohistochemical method were employed to detect amplification and overexpression of proto-oncogene c-erbB2 in 101 paraffin-embedded breast cancers. The results showed that c-erbB2 was amplified and overexpressed in 34.7% and 23.8% of examined cases respectively. The overexpression of c-erbB2 was correlated with, but not always paralled to the gene amplification. The moderate to high-level overexpression of c-erbB2 detected by immunohistochemistry was significantly associated with the size of the tumour and the number of lymph nodes involved. No differences were found in the alteratio of c-erbB2 gene and its protein expression between primary and metastatic breast cancers indicating that the genotypic and phenotypic changes of c-erbB2 occured prior to and maintained in the process of metastasis of breast cancer.

Cationic lipids for reporter gene and CFTR transfer to rat pulmonary epithelium

Increasing evidence indicates that cationic liposomes are capable of safely transferring foreign genes to pulmonary epithelium in vitro and in vivo. To transfer reporter genes and the cystic fibrosis transmembrane conductance regulator (CFTR) to mammalian respiratory epithelium we used two cationic lipid formulations: N-[1-(2,3-dioleoyloxy)propyl] N,N,N-triethylammonium chloride (DOTMA), and 1,2-dimyristyloxy-propyl-3-dimethylhydroxyethylammonium bromide (DMRIE) at a 1:1 molar ratio with dioleoyl phosphatidylethanolamine (DOPE). Lipid-DNA conjugates containing either CFTR or LacZ were instilled directly into the airways of Sprague-Dawley rats. Rats treated with LacZ cDNA in vivo demonstrated expression in 30-50% of the large and medium-sized airways, with some airways showing high efficiency gene transfer and expression (in the most proximal airways, 70-80% of surface epithelial cells were positive for expression of a nuclear targeted LacZ). While control and LacZ treated tracheas mounted in Ussing chambers showed minimal stimulation of transepithelial chloride (Cl)-currents by cAMP (suggesting low levels of endogenous rat CFTR activity), tracheas taken from animals receiving CFTR exhibited significant forskolin-stimulated currents at 72 h after gene transfer. Human CFTR gene expression was also detected by polymerase chain reaction (PCR) analysis of reverse transcribed lung RNA. These results, together with previous studies using lipid-mediated gene transfer in mice, help confirm the potential for cationic lipid-mediated gene transfer in the gene therapy of cystic fibrosis in humans.

Differential suppression of mammary and prostate cancer metastasis by human chromosomes 17 and 11

Metastasis suppressor activities have previously been mapped to human chromosomes 17 and 11. Decreased expression of the metastasis suppressor gene NM23, which is located on chromosome 17, has been correlated with increased metastatic potential in mammary cancers. A region on human chromosome 11, from 11p11.2-p13, has been shown to suppress metastasis in rat prostatic carcinoma cells. In both cases the metastasis suppressor activity had no effect on tumorigenicity or tumor growth rate, demonstrating that the encoded activities are distinct from effects of tumor suppression. To determine whether these human chromosomes encode general or tissue-specific metastasis suppressor activities, a truncated human chromosome 17 (i.e., pter-q23) and a full-length human chromosome 11 were separately transferred into highly metastatic rat mammary and prostate cancer cell lines and tested for their ability to suppress spontaneous metastasis in vivo. These studies demonstrated that when the pter-q23 region of human chromosome 17 is retained by the microcell hybrids, the metastatic ability of both mammary and prostatic cancer cells is suppressed. In contrast, when the pter-q14 region of human chromosome 11 is retained, only the metastatic ability of prostatic cancer cells is suppressed. Additional studies demonstrated that the metastasis suppressor activity encoded by the chromosome 17 pter-q23 region is p53-independent and not due to enhanced expression of NM23 protein.

Protein kinase C inhibits Na(+)-K(+)-2Cl- cotransporter activity in cultured rabbit nonpigmented ciliary epithelium

We examined the regulation of Na(+)-K(+)-2Cl- transporter activity by protein kinase C (PKC) in a cell line derived from rabbit nonpigmented ciliary epithelium. Na(+)-K(+)-2Cl- cotransporter activity was measured as the rate of bumetanide-sensitive potassium (86Rb) transport. Phorbol 12,13-dibutyrate (PBDu) was used to activate PKC. PBDu inhibited bumetanide-sensitive potassium (86Rb) uptake, with a half-maximal inhibitory concentration of approximately 0.1 microM. The inhibitory effect of PBDu on potassium uptake by the N(+)-K(+)-2Cl- cotransporter was abolished by PCK downregulation and diminished by 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine, a PKC inhibitor. PBDu inhibited Na(+)-K(+)-2Cl- cotransporter-mediated inward potassium (86Rb) transport by approximately 26% in control cells and by 40% in cells pretreated with ouabain. PKC activation also reduced the rate of bumetanide-sensitive potassium (86Rb) efflux in ouabain-treated cells but not in control (no oubain) cells. PBDu caused little change of intracellular sodium, potassium, or chloride, suggesting that an alteration of cytoplasmic ion composition is not responsible for the observed PBDu-induced changes in the rate of either inward or outward potassium movement mediated by the Na(+)-K(+)-2Cl- cotransporter.

Transport of cyclosporin A across the brain capillary endothelial cell monolayer by P-glycoprotein

P-glycoprotein, a multidrug transporter protein, exists in the brain capillary endothelium. To study the function of P-glycoprotein in brain capillary endothelium as a barrier against cyclosporin A, we examined the interaction of cyclosporin A with P-glycoprotein expressed in cultured brain capillary endothelial cells (MBEC4). P-glycoprotein of MBEC4 specifically bound [125I]iodoaryl azidoprazosin, and the binding was inhibited by cyclosporin A and vincristine. Intracellular accumulation of cyclosporin A in MBEC4 was about one-third the amount accumulated in mouse aortic endothelial cells (MAEC3), a cell line that did not express P-glycoprotein. The reduced accumulation of cyclosporin A in MBEC4 was increased by verapamil, a competitive inhibitor of transport function of P-glycoprotein. Cyclosporin A was preferentially transported from basal to apical side when the cell monolayer of MBEC4 was formed; however this transendothelial transport was not observed across cell monolayer of MAEC3. Verapamil inhibited the transendothelial transport of cyclosporin A across the MBEC4 monolayer. Thus P-glycoprotein in brain capillary endothelium could transport cyclosporin A across the endothelium from the basal to the apical side. These observations suggest that P-glycoprotein is involved in the complex function of the blood-brain barrier as a secretory detoxifying transporter of cyclosporin A.

Protein crystallization in space

The microgravity environment of space is an ideal place to study the complicated protein crystallization process and to grow good-quality protein crystals. A series of crystal growth experiments of 10 different proteins was carried out in space on a Chinese re-entry satellite FSW-2 in August, 1992. The experiments were performed for about two weeks at a temperature of 18.5 +/- 0.5 degrees C using a tube-like crystallization apparatus made in the Shanghai Institute of Technical Physics, Academia Sinica. More than half of 48 samples from 6 proteins produced crystals, and the effects of microgravity on protein crystal growth were observed, especially for hen-egg white lysozyme and an acidic phospholipase A2 from the venom of Agkistrodon halys Pallas. Analyses of the crystallization of these two enzymes in this mission showed that the microgravity environment in space may be beneficial to improve size, external perfection, morphology, internal order, and nucleation of protein crystals. Some of these positive microgravity effects were also demonstrated by the growth of protein crystals in gelled solution with the above two enzymes. A structural analysis of the tetragonal lysozyme crystal grown in space is in progress.

Structure of the mouse growth/differentiation factor 9 gene

Using a mouse GDF-9 cDNA as a probe, over 20 kb of sequence encompassing the GDF-9 gene was isolated from a mouse 129SvEv genomic library. Sequence analysis of the exons, exon-intron boundaries, and 5'- and 3'-non-translated regions was used to establish the structure of the mouse GDF-9 gene. The GDF-9 gene is encoded by two exons separated by a 2.9 kb intron. Multiple putative transcription start sites are detected between 31 and 57 bp upstream of the start site of translation and a putative polyadenylation signal lies 342 bp 3' of the end of translation. Knowledge of the GDF-9 gene structure will enable us to further understand the role of GDF-9 in ovarian physiology and development.

The proregion of cathepsin L is required for proper folding, stability, and ER exit

To investigate the role of the proregion in the biosynthesis and trafficking of mouse cathepsin L, cathepsin L cDNAs encoding proteins with altered proregions were constructed and their expression in COS cells was examined. As in transformed cells, normal mouse cathepsin L was secreted by COS cells. In contrast, two altered proregion cathepsin L proteins, one in which the proregion was deleted and a second in which the proregion was replaced with that of a homologous protein (aleurain), were retained within the cell and degraded over a period of 2-6 h. Immunofluorescence localization and the lack of effect of NH4Cl and brefeldin A on the turnover of the altered cathepsin L proteins indicated that their degradation occurred in the endoplasmic reticulum (ER). By using brefeldin A to induce colocalization of the UDPGlcNAc: lysosomal enzyme N-acetylglucosamine-1-phosphotransferase with the cathepsin L proteins in the ER, it was shown that the altered proteins were not susceptible to mannose phosphorylation as they exist in the ER. Trypsin sensitivity assays indicated that altered proregion proteins synthesized in COS cells or in vitro are misfolded. Taken together, these results indicate that the proregion plays an essential role in proper folding of cathepsin L. ER retention, decreased stability, and lack of mannose phosphorylation of the altered proteins are most likely secondary effects resulting from improper folding.

[Study of carbon agglutination test for the rapid diagnosis of rotavirus]

This paper reports the result of experiment of carbon agglutination test used for the diagnosis of Rotavirus. The results of our experiments demonstrate that this method has many advantages, such as simplicity, rapidity and specificity. One hundred and five stool samples were detected by carbon agglutination test and polyacrylamidegel electrophoresis. The result showed that no obvious difference in the positive rates of them. Thus, it can be concluded that CAT method can replace the PAGE in clinic.

Paternally inherited chloroplast polymorphism in Pinus: estimation of diversity and population subdivision, and tests of disequilibrium with a maternally inherited mitochondrial polymorphism

We have surveyed a chloroplast DNA restriction fragment length polymorphism in 745 individuals, distributed rangewide in eight allopatric natural populations of jack pine (Pinus banksiana Lamb.) and eight allopatric natural populations of lodgepole pine (Pinus contorta Dougl.). The polymorphic region of the chloroplast genome is located near duplicated psbA genes. Fourteen length variants were found in the survey, and these variants distinguished the two species qualitatively. Variant diversities were high in both species (hes = 0.43 in jack pine; hes = 0.44 in lodgepole pine). Population subdivision was weak within and among lodgepole pine subspecies and in jack pine (i.e., theta values were less than 0.05). This weak subdivision is compatible with theoretical predictions for paternally inherited markers in wind-pollinated outcrossers, as well as for polymorphisms with high length mutation rates. If these populations are at a drift-migration equilibrium, the chloroplast DNA restriction fragment data and previous mitochondrial frequency data from the same individuals are consistent with gene flow that is differential through seeds and pollen. The new data have permitted the first empirical tests of disequilibrium between maternally and paternally inherited factors. As expected, these tests failed to detect convincing evidence of nonrandom association between chloroplast and mitochondrial variants.

Inhibition of Na(+)-K(+)-ATPase activates Na(+)-K(+)-2Cl- cotransporter activity in cultured ciliary epithelium

Inhibition of Na(+)-K(+)-ATPase activates Na(+)-K(+)-2Cl- cotransporter activity in cultured ciliary epithelium. Am. J. Physiol. 266 (Cell Physiol. 35): C198-C205, 1994.--86Rb uptake experiments were conducted to measure Na(+)-K(+)-ATPase activity and Na(+)-K(+)-2Cl- cotransporter activity in a cell line derived from rabbit nonpigmented ciliary epithelium. The presence of a Na(+)-K(+)-2Cl- cotransporter was supported by the observation of a bumetanide-sensitive 86Rb uptake component that was dependent on the extracellular concentration of both sodium and chloride. Potassium influx mediated by the Na(+)-K(+)-2Cl- cotransporter and Na(+)-K(+)-ATPase accounted for approximately 46 and 33% of total potassium uptake, respectively, whereas both ouabain- and bumetanide-resistant uptake accounted for 9%. Inhibition of the Na(+)-K(+)-ATPase had a stimulatory effect on Na(+)-K(+)-2Cl- cotransporter activity, which was dependent on the extent and duration of Na(+)-K(+)-ATPase inhibition. Ouabain treatment stimulated the potassium (86Rb) efflux rate and reduced intracellular potassium ([K]i). Potassium channel blockers suppressed the ouabain-activated potassium efflux and inhibited the ouabain-induced activation of the Na(+)-K(+)-2Cl- cotransporter. We conclude that Na(+)-K(+)-ATPase inhibition leads to the opening of potassium channels, which exacerbates the depletion of cellular potassium; Na(+)-K(+)-2Cl- cotransporter stimulation caused by the fall of [K]i overrides the tendency of increased cellular sodium to inhibit the cotransporter.

The deduced amino-acid sequence of the cloned cpxR gene suggests the protein is the cognate regulator for the membrane sensor, CpxA, in a two-component signal transduction system of Escherichia coli

The cpxA gene of Escherichia coli K-12 encodes a membrane-associated sensor element of a two-component signal transduction system in bacteria. The cognate regulator element, however, has not yet been definitively identified. A 2.1-kb segment upstream from cpxA was amplified by polymerase chain reaction, cloned and sequenced. An open reading frame encoding 232 amino acids was found. It showed high homology to the regulator elements of two-component transduction systems. The newly identified gene, designated as cpxR, may encode the cognate protein receiving signals from CpxA.

[A study on gastric mucosa damage, antigen location, and virus dissociation in patients with epidemic hemorrhagic fever]

Gastric mucosa damage was investigated with techniques of gastroscopy, gastric biopsy, antigen location with immunohistochemical enzyme staining and virus dissociation in 135 patients with epidemic hemorrhagic fever (EHF). We found that the major pathologic finding in gastric mucosa is hemorrhage of squamous shape. EHF virus antigen exists in epithelial cytoplasm of the superficial layer and lamina propria of gastric mucosa and the virus is dissociated from gastric mucosa. The virus is identified as of field-rat serotype with electronmicroscopy and monoclonal antibody techniques. These results suggest that it is necessary to start antivirus therapy early and to give prophylactic measures to prevent gastric mucosa damage and upper digestive tract bleeding.

[The biological behaviors of inoculated B16 melanoma in mice: correlation with NK activity of the host]

B16 melanoma cells with different natural killer (NK) cell activity were inoculated subcutaneously in mice. Observations were made on the relation of NK cell activity to tumor growth, infiltration and metastasis on the one hand and, the sensitivity of the tumor cells to NK cells before and after tumor implantation on the other. It was seen that NK cells could not only inhibit tumor growth, infiltration and metastasis, but also induce tumor NK-tolerance of the tumor. When the NK-tolerant tumors were resected and implanted into ordinary mice, the biological behaviors of NK-tolerant B16 tumor cells were more malignant than wild (original) B16 cells. The results of this study show that the in vivo interaction between NK cells and tumor cells can positively and negatively influence the tumor's biological behaviors.

Serum cholesterol determined by liquid chromatography with 6-chlorostigmasterol as internal standard

We describe an accurate and precise method for determining serum cholesterol by high-performance liquid chromatography (HPLC). After addition of 6-chlorostigmasterol as internal standard, serum is treated with alcoholic potassium hydroxide. Subsequently the cholesterol and internal standard are extracted from the mixture into n-hexane and then derivatized to phenylurethanes for measurement by HPLC with ultraviolet detection. The effective chromatographic separation and the use of an appropriate internal standard make this procedure free from interferences by other serum sterols and precise. The mean cholesterol concentration in Standard Reference Material (SRM) 909 (human serum) assayed by this procedure (4.346 mmol.g-1 x L-1) agreed well with the value assigned by the National Institute of Standards and Technology (4.359 mmol.g-1 x L-1). Within-run and total CVs were 0.56% and 0.78%, respectively. Therefore the performance of this procedure is sufficiently good to allow its use as a candidate reference method for serum cholesterol determination.

Serum cholesterol determined by liquid chromatography with 6-chlorostigmasterol as internal standard

We describe an accurate and precise method for determining serum cholesterol by high-performance liquid chromatography (HPLC). After addition of 6-chlorostigmasterol as internal standard, serum is treated with alcoholic potassium hydroxide. Subsequently the cholesterol and internal standard are extracted from the mixture into n-hexane and then derivatized to phenylurethanes for measurement by HPLC with ultraviolet detection. The effective chromatographic separation and the use of an appropriate internal standard make this procedure free from interferences by other serum sterols and precise. The mean cholesterol concentration in Standard Reference Material (SRM) 909 (human serum) assayed by this procedure (4.346 mmol.g-1 x L-1) agreed well with the value assigned by the National Institute of Standards and Technology (4.359 mmol.g-1 x L-1). Within-run and total CVs were 0.56% and 0.78%, respectively. Therefore the performance of this procedure is sufficiently good to allow its use as a candidate reference method for serum cholesterol determination.

Taxonomic and population differentiation of mitochondrial diversity inPinus banksiana andPinus conforta

We have studied two mitochondrial DNA polymorphisms in 741 individuals from 16 allopatric populations ofPinus banksiana Lamb. andPinus contorta Dougl. Restriction fragments of both polymorphisms distinguished the two species qualitatively, except in aP. Banksiana population whose ancestors were involved in hybridization withP. contorta.COXI-associated restriction fragments were monomorphic within species, whileCOXII-associated restriction fragments were highly variable inP. contorta (Hes=0.68). Population differentiation was substantial inP. contorta (Fst=0.31 among subspecies; mean Fst=0.66 within subspecies) and consistent with predictions for maternally inherited markers. Plant mitochondrial markers appear to be useful for the investigation of seed migration routes, hybridization and introgression, breeding zone designation, and the development of germ plasm conservation sampling strategies.