A lysine residue involved in the inhibition of vacuolar H(+)-pyrophosphatase by fluorescein 5'-isothiocyanate

Vacuolar proton pumping pyrophosphatase (H(+)-PPase; EC 3.6.1.1) plays a central role in the electrogenic translocation of protons from cytosol to the vacuole lumen at the expense of PP(i) hydrolysis. A fluorescent probe, fluorescein 5'-isothiocyanate (FITC), was used to modify a lysine residue of vacuolar H(+)-PPase. The enzymatic activity and its associated H(+) translocation of vacuolar H(+)-PPase were markedly decreased by FITC in a concentration-dependent manner. The inhibition of enzymatic activity followed pseudo-first-order rate kinetics. A double-logarithmic plot of the apparent reaction rate constant against FITC concentration yielded a straight line with a slope of 0.89, suggesting that the alteration of a single lysine residue on the enzyme is sufficient to inhibit vacuolar H(+)-PPase. Changes in K(m) but not V(max) values of vacuolar H(+)-PPase as inhibited by FITC were obtained, indicating that the labeling caused a modification in affinity of the enzyme to its substrate. FITC inhibition of vacuolar H(+)-PPase could be protected by its physiological substrate, Mg(2+)-PP(i). These results indicate that FITC might specifically compete with the substrate at the active site and the FITC-labeled lysine residue locates probably in or near the catalytic domain of the enzyme. The enhancement of fluorescence intensity and the blue shift of the emission maximum of FITC after modification of vacuolar H(+)-PPase suggest that the FITC-labeled lysine residue is located in a relatively hydrophobic region.

[Effects of lotensin and nitrendipine on plasma fibrinogen and platelet aggregation in hypertensive patients]

Plasma fibrinogen and platelet aggregation were measured by turbidimetric immunoassay, turbidimetry in 47 hypertensive patients and 20 normotensive control subjects. Among the 47 hypertensives, 24 cases were received lotensin and 23 nitrendipine. The plasma fibrinogen was increased and platelet aggregation enhanced in hypertensive patients before treatment. Platelet aggregation decreased after 8 weeks of treatment with lotensin or nitrendipine respectively. Lotensin decreased plasma fibrinogen whereas nitrendipine did not. It was concluded that both lotensin and nitrendipine decreased platelet aggregation; lotensin decreased plasma fibrinogen but nitrendipine did not.

Distinct roles for amino- and carboxyl-terminal sequences of SPRR1 protein in the formation of cross-linked envelopes of conducting airway epithelial cells

The small proline-rich protein, SPRR1, is a marker gene whose expression in conducting airway epithelium is elevated under a variety of conditions that enhance squamous differentiation. The purpose of this study is to elucidate the nature of the SPRR1 sequence involved in cross-linked envelope formation in a tissue/cell type, such as conducting airway epithelium, that normally does not express squamous function except after injury or maintenance in culture. For this, a Flag-SPRR1 fusion protein expression system has been developed. Using the liposome-mediated gene transfer technique on passage 1 culture of human tracheobronchial epithelial (TBE) cells, the Flag-SPRR1 fusion protein can be expressed and detected immunologically by both anti-Flag and anti-SPRR1 antibodies. The incorporation of Flag-SPRR1 fusion protein into cross-linked envelopes can be demonstrated when transfected human passage 1 TBE cultures are treated with phorbol 12-myristate 13-acetate and high calcium (1.5 mM). By deletion and site-directed mutagenesis, two distinct roles of the amino- and carboxyl-terminal sequences of SPRR1 have been demonstrated. First, we demonstrated that the amino-terminal sequence of SPRR1 protein is required for the incorporation of the fusion protein into cross-linked envelopes, whereas a deletion on the carboxyl-terminal region or on the middle repetitive unit has no effect. Interestingly, insertion of a 24-amino acid peptide of monkey MUC2 repetitive sequence in the amino-terminus of SPRR1 protein had a stimulatory effect. Site-directed mutagenesis on the following amino acid residues, Lys(7), Gln(88), and Lys(89), which were found previously to participate in the cross-linked envelope formation of keratinocytes, had no detrimental effect on the incorporation. However, mutations on Gln clusters, such as Gln(4)-Gln(6) and Gln(22)-Gln(25), had detrimental effects on the incorporation. These results suggest an amino-terminal sequence-dependent and multiple cross-linked sites for the incorporation of Flag-SPRR1 fusion protein into cross-linked envelopes of cultured human TBE cells. Second, we demonstrated that the carboxyl terminus of SPRR1 protein is required for a high level of Flag-fusion protein expression. A deletion in the carboxyl region or a mutation on the last lysine residue of the carboxyl end had a detrimental effect on the level of Flag-SPRR1 fusion protein expressed in transfected cells. In contrast, there was only a slight decrease in the level of expression if the amino-terminus was deleted. Interestingly, the efficiency for fusion protein to incorporate into cross-linked envelopes was elevated by the mutation at the carboxyl end. These results suggest distinct roles, perhaps coordinately, for both amino- and carboxyl-terminal sequences in the regulation of the life cycle of SPRR1 protein in cultured TBE cells.

Anisodamine as an effective drug to treat snakebites

Anisodamine is a natural alkaloid drug isolated from the plant Anisodus tanguticus growing in western China. The chemical structure and pharmacological action are just like the cholinergic receptor blocking agents atropine or scopolamine. The specific characteristic of the drug is being able to relieve the dangerous situation of microcirculatory failure, especially in case of DIC or renal failure. The prognosis of the patients will be quite good. Another characteristic of the drug is that no serious toxic reaction occurs even in successive doses given intravenously up to 500 mg a day. This is about fifty times greater than a common dose of 10 mg. Since we begin with the drug as a routine medication for the symptomatic treatment of renal failure, DIC bleeding, and microcirculatory failure, we should say that the specific antivenin and anisodamine are two treasure drugs for snakebites.

Molecular modelling of trimethoprim complexes of human wild-type and mutant dihydrofolate reductases: identification of two subsets of binding residues in the antifolate binding site

Computer-assisted molecular modelling was used to generate structures for the trimethoprim (TMP):NADPH:dihydrofolate reductase (DHFR) ternary complexes for human wild-type DHFR and for five DHFR mutants (L22R, L22F, F31S, F31W and Q35P). The mutants correspond to DHFR proteins that have been isolated from tissues exposed to chronic or high dose methotrexate (MTX) and show decreased sensitivity to antifolate inhibition. Analysis of the TMP:DHFR interactions suggest the presence of two subsets of TMP binding residues in the DHFR antifolate binding site. One subset of these residues (GLU30, PHE34, ILE60 and VAL115) are common to each DHFR complex studied and are referred to as core residues. The other TMP binding residues vary among the DHFR complexes studied and are referred to as noncore residues. The core residues exhibit a greater number of TMP contacts/residue and form more stable TMP interactions than noncore residues. Additionally, the core and noncore residues make contact with different regions of the TMP structure. Information presented here provides additional insight into the design of new agents for the improved inhibition of wild-type DHFR and the simultaneous inhibition of both wild-type and mutant DHFR molecules.

[Deletion analysis and functional studies of the promoter from commelina yellow mottle virus]

Commelina Yellow Mottle Virus(CoYMV) is a double-stranded, circular DNA virus and its promoter could direct GUS gene specifically expressing in phloem tissue of transgenic tobacco plants. To determine the optimal promoter sequence for pholem-specific gene expression, CoYMV promoter was deleted from its 5 end to form promoter fragments with 5 different lengths. Chimeric GUS genes were constructed using the promoter deletion based on the binary vector pBI121. Transgenic tobacco plants evidenced by PCR analysis were obtained with each kind of chimeric GUS gene structure by Agrobacterium mediated transformation. The results of GUS activity assay and histo-chemical staining showed that most of the chimeric GUS genes were expressed in transgenic plants. The GUS activity with the promoter deleted to -870 bp was about 78% higher than that of the full length promoter(1040 bp) and was a little higher than that of the promoter deleted to -585 bp, but the difference is not significant. The GUS activity reduced significantly when the promoter was deleted to -447 bp or -232 bp, whereas the property of phloem-specific expression pattern was still retained. When the promoter was deleted to -44 bp, just upstream adjacent to the TATA box, its tissue-specificity was lost and the activity was reduced to undetectable level. These results suggest that the region between -870 bp-232 bp and downstream of -232 bp of CoYMV promoter could be responsible for promoter activity and tissue specific expression, respectively. A negative regulation sequence might exist upstream of -870 bp of the CoYMV promoter. Therefore, we recommend that the optional CoYMV promoter sequence for phloem specific expression could be downstream from -870 bp or -585 bp. In comparison with CaMV 35S promoter, the GUS activity when driven by -870 bp CoYMV promoter was about 70% of that when driven by the 35S promoter. Considering the fact that 35S promoter-GUS gene is constitutively expressed, while the CoYMV promoter-GUS gene is expressed only in phloem tissues, the activity of the latter in phloem may be the same with or even higher than that of the 35S promoter.

[Hepatic metastasis from advanced gallbladder carcinoma: clinicopathological study]

OBJECTIVE

To clarify the characteristics of the related clinicopathological factors in cases of liver metastasis from carcinoma of the gallbladder (LmGbCa), and to provide some insights into the surgical management of LmGbca.

METHOD

One hundred fifty-nine patients with subserosal (ss) cancer were studied.

RESULT

31 (19.4%) of the patients were found to have LmGbCa. Clinicopathologically, LmGbCa cases showed significant correlations with hinf(3) (P < 0.05), a depth of invasion of more than ss (P < 0.05), ly(3) (P < 0.05), v(3) (P < 0.01), and the location of the primary lesion on hep or circ (P < 0.01).

CONCLUSION

Hepatectomy of S4 and S5 segments should be used when 2 risk factors of liver metastases were found operatively, and radiation therapy or chemotherapy should be combined with resection when 1 risk factor of liver metastasis and lymphatic invasion was found.

Theory and Experiment on the Measurement of Kinetic Rate Constants for Surfactant Exchange at an Air/Water Interface

The paper focuses on the measurement of the rate constants for the kinetic steps of adsorption and desorption of surfactant between an air/water surface and the aqueous bulk sublayer adjacent to the surface. Kinetic constants are determined in nonequilibrium experiments in which either a clean surface is contacted with a bulk solution and surfactant diffuses toward and adsorbs onto the interface, or the area of an established monolayer in equilibrium with an underlying solution is changed, and surfactant exchanges between the surface and bulk. The dynamic tension change due to the surfactant exchange is measured, and compared to predictions of kinetic-diffusive transport models in order to infer the kinetic coefficients as well the diffusion coefficients. Model comparisons for highly surface active surfactants have resolved only the diffusion coefficient as the transport was found to be diffusion controlled; kinetic constants have only been established for less active materials such as alcohols or bolaform surfactants. In this study, we demonstrate that kinetics can be differentiated from diffusion in clean interface adsorption and re-equilibration if high bulk concentrations of the surfactant are used, or in re-equilibration, if the surface is compressed sufficiently. We first establish theoretically that mass transfer shifts from diffusion-limited to mixed as the bulk concentration increases in clean interface adsorption, or the surface compression is increased in re-equilibration. We then experimentally verify this idea by using the polyethoxylated surfactant C12E6 (C12H25 (OCH2CH2)6-OH) and by measuring dynamic surface tensions in clean interface adsorption and re-equilibration, respectively by the shape analysis of pendant bubbles. We find values of 6 x 10(-10) m2/s for the diffusion coefficient, and 1.4 x 10(-5) m/sec and 1.4 x 10(-4) s-1 for the adsorption and desorption rate constants, respectively, in a Frumkin kinetic formulation. While the adsorption constant is comparable to previously measured values for the less surface active surfactants, the desorption rate constant is a few orders of magnitude smaller. This indicates that the more surface active materials may have much smaller desorption rate constants than had been previously anticipated based on the studies of the less surface active materials. Copyright 1998 Academic Press.

[Plasmid profile typing of Salmonella typhimurium and its distribution in some provinces and cities of China]

OBJECTIVE

To study the relationship between the infection and prevalence of Salmonella typhimurium.

METHODS

From 1980 to 1995, when Salmonella typhimurium infection was prevalent in north and south China, a total of 2,655 isolates of Salmonella typhimurium were collected from 19 provinces, municipalities, and autonomous regions and Hong Kong Special Administrative Region for plasmid profile analysis. The profiles consisting of some small plamids were recorded with capital letters A to J, and the profile which was free from small plasmid was recorded with capital letter O. Large plasmid in molecular weights of 140-20 Mdal showing in profiles was recorded with Arabic numerals 9 to 0 respectively. Having two or more than two large plasmids, the profile was recorded with two or more Arabic numerals.

RESULTS

The 2,655 strains were divided into 11 plasmid profile groups and 168 plasmid profile types. Of 52 plasmid profile types frequently isolated, plasmid profile type O 4 was distributed extensively in 16 provinces, municipalities, and autonomous rehions and Hong Kong. Plasmid profile type O 5 was isolated in 5 provinces and Hong Kong, mostly in Jiangxi and Hubei. Plasmid profile type J 4 was isolated in 7 provinces, municipalities and autonomous regions, mostly in Jiangxi. Five plasmid profile types of Group A caused a big prevalence of nosocomial infection in Henan. Type A 6 was also isolated in Xinjiang and Anhui. Six plasmid profile types of Group E were prevalent in Xinjiang predominantely, three types caused nosocomial infection in Shanghai, type E 82 caused nosocomial infection and food poisoning in Liaoning. Type F 4 was isolated in 4 provinces, mostly in jiangxi and Fujian. Many plasmid profile types were prevalent local. Types B 5, BCEG 60, BE 6, B' 0 G 6, G 5 and EG 6 were prevalent in Jiangxi, Types IF'4, IF'H40 and F 9864 were prevalent in Sandong, Type IF'4 was also isolated in Jiangsu and Hubei, Type IF 40 in Anhui, Type BH 6 in Huibei, and Type EH 5 in Fujian.

CONCLUSION

Plasmid profile analysis showed the same types in the prevance but different plasmid profiles in different provinces.

[Analysis gastrodin in various types of Gastrodia elata Bl]

This paper analyzes the gastrodin in various types of Gastrodia elata quantitatively and qualitatively by means of TLC and HPLC. The TLC result shows the various types of G. elata to be almost the same. The HPLC result reveals that the peak number and retention times of these various types are similar, but the peak areas or peak heights are different.

Restriction by ankyrin of band 3 rotational mobility in human erythrocyte membranes and reconstituted lipid vesicles

Rotational diffusion of eosin-5-maleimide-labeled band 3 was measured in erythrocyte membranes at pH 9.4-10.4. Band 3 was found to be more mobile in this pH range than at pH 7.5. Similar results were obtained with spectrin-actin-depleted membranes, where it was further shown that ankyrin is the only detectable protein released from the membrane at pH 10. Further experiments were performed at pH 7.5 to investigate the effects of rebinding purified ankyrin and/or band 4.1 to ghosts stripped of skeletal proteins. Ankyrin was found to reduce band 3 rotational mobility, but band 4.1 had no effect. A fluorescence binding assay revealed that fluorescein isothiocyanate-labeled ankyrin had similar binding parameters to those reported previously using 125I labeling. Finally, the rotational mobility of purified band 3 reconstituted into lipid bilayers was determined before and after ankyrin binding. The results of these reconstitution experiments were globally analyzed, assuming the existence of two populations of band 3 with different correlation times. The faster correlation time is consistent with that expected for either dimers or compact tetramers of band 3. Ankyrin binding reduces the proportion of band 3 contributing to the faster component. This result demonstrates that ankyrin promotes the association of band 3 into more slowly rotating complexes independently of any other components of the erythrocyte membrane. It has been reported that ankyrin contains two binding sites for band 3 [Michaely, P., & Bennett, V. (1995) J. Biol. Chem. 270, 22050-22057]. The results of the present study are thus explained by the ability of ankyrin to cross-link band 3 into larger diameter complexes. Cross-linking by ankyrin in part accounts for the slow components in the anisotropy decays of band 3 in the erythrocyte membrane. Other factors which probably influence band 3 aggregation include the membrane "fluidity" and protein concentration.

[Esterase isoenzyme of various types in rhizoma Gastrodiae]

By means of polyacrylamide gel slab electrophoresis, the esterase isoenzyme of various types in Gastrodia elata in different growing periods was studied and the relativity and difference in physiology and biochemistry were discussed. The result reveals that apparent variety of Rhizoma Gastrodiae is not decided by genetic factors.

[Local arterial infusion of 5-FU in treatment of acute necrotic pancreatitis]

In 19 patients with acute necrotic pancreatitis the cordis tube was inserted in the arterial suppling blood. If the necrotic site at the head of pancreata, the tube was placed in the arteria gastroduodenalis or arteria pancreaticoduodenalis. When the site at the trunk or rearby, the tube was placed in the arteria lienalis or coeliaca, and when the necrosis all over the pancreata, the tube in the arteria coeliaca. Through the tube, infusion drugs mainly 5-FU were given within 20 days from onset of the disease. Compared with the controlled group of 68 patients, the mortalities were 10.5% and 30.9%, and the rates of organ falls 5.3% and 42.7%. The second infection of bacterium was 5.3% and 44.1% respectively. We suggest that local arterial infusion of 5-FU is an effective treatment for acute necrotic pancreatitis and creats conditions for delayed operations, clears the remaining tissue of necrotic pancreatitis easily.

[The cloning of threonine operon in vivo and mutagenesis in vitro in E. coli]

Report here was the selection of the E. coli strain producing 1.2% threonine. The wild type threonine operon was cloned in vivo and subcloned in vitro. The subclone was mutagenizied in vitro and a clone pTHR12-9-1 producing threonine was obtained. Also the effect of pTHR12-9-1 on threonine yield of hosts producing different amount of threonine was studied. We found that pTHR12-9-1 could promote the production of threonine in lower yield hosts, but it reduced the production of threonine in higher yield hosts. The phenomenon was discussed.

Multigene families in African swine fever virus: family 505

Sequencing of restriction fragment EcoRI A-SalI C of African swine fever virus has revealed the existence of a multigene family, designated family 505 because of the average number of amino acids in the proteins, composed of seven homologous and tandemly arranged genes. All the genes of family 505 are expressed during infection. Primer extension analysis showed that transcription is initiated a short distance (3 to 62 nucleotides) from the start codon of the corresponding open reading frame. The proteins of family 505 showed similarity to those of family 360 from African swine fever virus. In particular, a striking conservation of three regions at the amino terminus of the polypeptides was observed.

Swine leukocyte antigen and macrophage marker expression on both African swine fever virus-infected and non-infected primary porcine macrophage cultures

Swine leukocyte antigens (SLA) and a macrophage specific marker were monitored on porcine macrophages cultured with or without macrophage colony stimulatory factor (M-CSF) and on cells infected with African swine fever virus (ASFV). SLA expression was maximal either in the total cell extract or on the cell surface at 3-4 days of culture; after 4 days these values began to decrease. Fluorescence analyses of immunostained macrophages cultured with or without M-CSF indicated a major upward shift in the number of SLA Class I molecules on individual macrophages whereas for SLA Class II both a novel expression of Class II and an upward shift in the number of molecules per cell were evident. Infection of 3-day-old macrophage cultures with three different isolates of ASFV resulted in minor changes in surface expression of SLA Class I, SLA Class II, and macrophage markers. No differences in infection with ASFV was observed whether macrophages were SLA Class II positive or negative, nor was there blocking by anti-SLA Class I or Class II monoclonal antibodies of ASFV infection of cultured macrophages.

Multivariate comparison of the forelimb between stump-tailed and rhesus macaques

Rhesus macaques and stump-tailed macaques are sympatric in western Yunnan (China), coexisting or occupying habitats that show little difference. This paper tests hypotheses based on theoretical expectation from the differing biomechanical demands of terrestrial and arboreal quadrupedalism in stump-tailed macaques and rhesus macaques, respectively. Individuals of these two macaque taxa were markedly separated by the first two principal components and discriminant analyses based on 18 variables of the upper limb. The rhesus macaques appear to be more adapted for arboreal quadruped habits because of elongation of the clavicle and forearm, a larger humeral head and greater midshaft sagittal diameters of the radius and ulna.

[A new serotype of Salmonella IIIb]

An enterobacterium culture, S3188, providing with Salmonella biological characteristics, except exhibiting indole positive reaction, was isolated from the intestinal content of reptile a snake. It utilized malonate, did not ferment dulcitol, it attacked lactose promptly, and ONPG positive. H antigens appeared diphasic. By cross agglutination and absorption tests, it was demonstrated that the antigenic formula of this strain is 53:1, Z13:e, n,(Z15)... It was found to be a new serotype of Salmonella IIIb.