Cloning of 1-aminocyclopropane-1-carboxylate (ACC) synthetase cDNA and the inhibition of fruit ripening by its antisense RNA in transgenic tomato plants

A 1.7 kb fragment of ACC synthetase cDNA, one member of the ACC synthetase multigene family, was amplified from total tomato cDNA through a polymerase chain reaction (PCR) and cloned in E. coli. Restriction mapping and sequencing analysis confirmed its fidelity and correctness. The cloned ACC synthetase gene was then inserted into a binary vector pBin437, in an inverted orientation between the CaMV 35S promoter with duplicated enhancers and the Nos 3' transcriptional termination sequence, to construct an expression vector pBACC. Transgenic tomato plants were obtained by A. tumefaciens-mediated transformation of cotyledons. PCR detection and Southern blot analysis confirmed the integration of the antisense ACC synthetase gene in the transformed tomato genome. The results from RT-PCR of RNAs isolated from transgenic tomato leaves confirmed that antisense ACC synthetase RNA was synthesized in these transgenic plants. The amount of ethylene released from transgenic tomato fruits was reduced significantly to about 30% of that released by non-transformed controls. The inhibition effect of antisense RNA on fruit ripening was observed in transgenic plants and their progeny (T1). The shelf life of transgenic tomato fruits was at least 60 days at room temperature without significant change in hardness and color. After 15-20 days of treatment of the transgenic fruits with ethylene, most of them reached the ripe stage. The antisense ACC synthetase gene was inherited as a single gene in the progenies of transgenic tomatoes determined by T1 progeny analysis, consistent with the results of Southern blot analysis. Transgenic homozygotes expressing antisense ACC synthetase RNA showed prolonged shelf life in the T2 progeny.

Adenovirus-mediated manganese superoxide dismutase gene transfer to hamster cheek pouch carcinoma cells

As a first step in evaluating the tumor suppressor activity of the manganese superoxide dismutase (MnSOD) gene on established tumors in vivo, we used adenovirus-mediated gene transfer as a means of delivering the MnSOD cDNA to hamster cheek pouch carcinoma (HCPC-1) cells in vitro. HCPC-1 cells were transduced with the adenovirus-MnSOD construct (AdMnSOD) at multiplicities of infectivity (MOI) of 0, 10, 25, 50, 100, 150, and 200 MOI or with the adenovirus-LacZ reporter gene construct (AdLacZ) at 100 MOI. Dose-dependent increases in MnSOD immunoreactivity were seen on Western blotting and indirect immunofluorescence microscopy with increasing AdMnSOD titers. Maximal immunoreactivity was observed at 100 MOI AdMnSOD with both techniques. Moreover, we observed a concomitant 6-7-fold increase in MnSOD activity compared with parental cell levels that also peaked at 100 MOI AdMnSOD. To determine the effect of transgene-expressed MnSOD on tumor cell behavior, we examined cell growth, plating efficiency, and anchorage-dependent growth in soft agar. Cell number measured on day 13 decreased approximately 50% with 100 MOI AdMnSOD (P < 0.05) compared with parental cells. Moreover, cell doubling time increased from 38 to 44 h with 100 MOI AdMnSOD. Plating efficiency and cell growth in soft agar decreased approximately two-thirds with 100 MOI AdMnSOD (P < 0.001). These assays of the transformed phenotype in vitro all appeared to show maximal effect with 100 MOI AdMnSOD. As tumor growth in vivo is most predictable by a combination of these in vitro data, our results suggest that if MnSOD can be effectively delivered to a tumor in vivo using the adenovirus paradigm, effective tumor growth suppression can be observed.

[Treatment of posterior urethral break caused by pelvic fracture and inflammatory urethral stricture via laying three silicone tubers into urethra]

We investigated a new approach for the treatment of posterior urethral break caused by pelvic fracture and inflammatory urethral stricture. 7-10 days after the operation of urethral realignment on patients with urethral break caused by pelvic fracture or after forced dilatation of inflammatory urethral stricture, three silicone tubers were laid into urethra and kept there for three months. In 66 cases of urethral break, the cure rate (58/66) was 87.9%, the improving rate (2/66) 3.0% and the failure rate (6/66) 9.1%. In 15 cases of inflammatory urethral stricture, the recovery rate was 100%. In this group of 81 cases, the cure rate was 92.6% and failure rate was only 7.4%. This new therapeutic approach proved to be simple, safe and effective. It could also dramatically reduce the infection or the stricture of urethra.

Rapid identification and isolation of zebrafish cDNA clones

A fast and economical approach, referred to as cDNA clone tagging, was adapted to identify and isolate zebrafish cDNA clones. The basic approach was to partially sequence the coding region of size selected cDNA clones and the partial sequences were then used as tags for identifying the clones through homology search. To benefit maximally from the tagging approach, two cDNA libraries, derived from embryonic and adult fish poly(A)+ RNAs, respectively, were constructed by unidirectional cloning; conceptually, they have the potential to represent all expressed zebrafish genes. A total of 1084 clones were sequenced from the two libraries, and 511 clones were identified, based on sequence homology. These identified clones were derived from at least 261 genes, encoding 48 translational machinery proteins, 47 cytosolic proteins, 43 cytoskeletal proteins, 41 nuclear proteins, 32 membrane proteins, 22 secreted proteins, 20 mitochondrial proteins and 8 proteins with an unknown location. Of the 261 distinct cDNA clones identified, 254 were isolated for the first time in the zebrafish. These tagged cDNA clones, identified and unidentified, provide rich resources for developmental analysis as well as mapping of zebrafish genome. The long-term objective of this study is to establish a tagged zebrafish gene library that can be accessed both by hybridization screening against the plasmid DNAs and by electronic screening using the sequence information.

Inhibition of cell growth and sensitization to oxidative damage by overexpression of manganese superoxide dismutase in rat glioma cells

The effects of overexpression of human manganese superoxide dismutase (MnSOD) on cell proliferation and response to oxidative stress in rat glioma cells were studied. MnSOD-overexpressing cells had a 2- to 14-fold increase in MnSOD activity, but did not have consistent changes in the activities of CuZnSOD, catalase, or glutathione peroxidase. Cells with more than a 5-fold increase in MnSOD activity became more sensitive to radiation, 1,3-bis(2-chloroethyl)-1-nitrosourea, and buthionine sulfoximine and had a lower growth rate than parental and vector control cells. The sensitivity to 1,3-bis(2-chloroethyl)-1-nitrosourea was partially reduced by pyruvate, a H2O2 scavenger. Our results suggest that overexpression of MnSOD can cause an imbalance of antioxidant enzymes, which we hypothesize results in an elevation of intracellular H2O2. Overexpression of MnSOD can either inhibit cell proliferation or increase cell death by oxidative agents, depending on the levels of peroxide-removing enzymes.

Manganese-containing superoxide dismutase overexpression causes phenotypic reversion in SV40-transformed human lung fibroblasts

Manganese superoxide dismutase (MnSOD) has been found to be low in a wide range of tumor cells as well as in vitro-transformed cell lines and has been implicated as a new type of tumor suppressor gene. The relationship between MnSOD activity and the malignant phenotype was studied by transfection of MnSOD cDNA into the SV40-transformed human fibroblast cell line WI-38 VA13 subline 2RA. The integration and expression of the exogenous MnSOD cDNA was confirmed in three selected clones with a 2-3.5-fold increase in MnSOD activity. The effect of elevated expression of MnSOD on the cell phenotype was determined by observing growth characteristics. Compared with the parental and neo control cells, the MnSOD-overexpressing clones had a slower growth rate, lower plating efficiency, increased anchorage dependence, and morphological differences. These changes were correlated strongly with the level of MnSOD activity. The results suggest that an increase of MnSOD activity can reverse part of the malignant phenotype in SV40-transformed human fibroblast cells. A possible mechanism is that overexpression of MnSOD might alter the intracellular redox state by modulation of the balance of reactive oxygen species.

Age-of-onset related HLA-DQA1 genetic heterogeneity of insulin-dependent diabetes mellitus

OBJECTIVE

To clarify whether there is an association of insulin-dependent diabetes mellitus (IDDM) susceptibility with HLA-DQA1 locus in adult-onset IDDM.

PATIENTS AND METHODS

Possible heterogeneity in immunogenetic aspects was investigated by comparing the findings on relationship between HLA-DQA1 52 Arg(+) and IDDM predisposition in three groups with different ages of IDDM onset (group A 14 years, group B 15-30 years, group C > 31 years).

RESULTS

The frequency of HLA-DQA1 52 Arg(+) in group A (87.5%) was higher than that in control (53.9%, P < 0.05) and in group B and C (P < 0.05). The frequency of HLA-DQA1 52 Arg(+)/Arg(+) phenotype in group A (75%) was higher than that in group C (23.1%, P < 0.05).

CONCLUSION

The contribution of HLA-DQA1 52 arginine to IDDM susceptibility is heterogeneous. Further study is necessary to clarify the immunogenetic entity of IDDM.

[Changes in cytosolic free calcium and thromboxane B2 synthesis in platelets from diabetic subjects]

Using fura-2, a fluorescence indicator, we evaluated the changes of platelet cytosolic free calcium concentration ([Ca2+]i) and its role in regulation of thromboxane B2 (TXB2) synthesis in patients with diabetes mellitus (DM group, n = 27) and in healthy subjects (control group, n = 15). The A23187-evoked elevation of [Ca2+]i and TXB2 production were higher in the DM group than in the control group (P < 0.01 respectively). The rise in [Ca2+]i was correlated positively with TXB2 production. In contrast, stimulation with arachidonic acid, TXB2 production was unaltered between the groups, although arachidonate-induced [Ca2+]i was higher in the DM group than in the control group (P < 0.05). The results suggested that changes in platelets [Ca2+]i in diabetic subjects may contribute to increase in TXB2 synthesis, involved libration of free arachidonate from membrance phospholipids by the action of phospholipases. Since no significant difference was found between the diabetic patients with microangiopathy (n = 13) and without microangiopathy (n = 14), the results above may be involved in the development of diabetic microangiopathy.

[The usefulness of transcutaneous gas monitoring during hemorrhagic shock; discrepancy between the two transcutaneous gas tensions of anterior thorax and femur]

We measured transcutaneous gas tensions of both anterior thorax and femur. The differences between the two transcutaneous gas tensions were compared, as well as the relationship between the two transcutaneous and mixed venous blood gas tensions, in 10 dogs during hemorrhagic shock. The changes in femoral transcutaneous gas tensions correlated better with the changes in mixed venous gas tensions. The correlation between the two transcutaneous gas tensions were fairly good (oxygen tensions; r = .827, carbon dioxide tensions; r = .867). However, the discrepancy between the two gas tensions became greater in severe shock. Hence, oxygen tensions became smaller and carbon dioxide tensions became greater on femur than on anterior thorax. This indicates the possibility of "maldistribution of blood flow", which has already been detected between vital organs and skin, also exists between peripheral and central skin. Therefore, transcutaneous gas tensions should be monitored at peripheral skin, where gas tensions show greater changes and reflect systemic perfusion precisely than at central skin, during shock.

The effect of anti-CD4 on helper function of CD4,45RA+ versus CD4,45RO+ T cells

Here we have investigated and compared the effects of anti-CD4 on helper function of CD4,45RA+ versus CD4,45RO+ T cells. Only CD4,45RO+ cells, but not CD4,45RA+ cells were able to promote B cell differentiation resulting in immunoglobulin production in vitro (IgM as well as IgG) which could be inhibited by anti-CD4 MoAbs (MAX.16H5 and T151). In pokeweed mitogen (PWM)-induced B cell proliferation a similar pattern of responsiveness was obtained. When we studied the anti-CD4 effects on cytokine production in T cells stimulated in mixed lymphocyte reaction (MLR) or by mitogens, we found that neither IL-2 nor IL-4 production was dramatically influenced by anti-CD4 in CD4,45RO+ cells. This led us to the conclusion that the inhibitory effect of anti-CD4 on B cell proliferation and immunoglobulin secretion was not due to inhibition of cytokine production. To clarify this point, we investigated the ability of anti-CD4 to inhibit conjugate formation between B and T cells. It was found that CD4,45RO+ T cells formed more conjugates than CD4,45RA+ cells, and that only the conjugate formation by CD4,45RO+ T cells was inhibited by anti-CD4. These results suggest that (i) anti-CD4 inhibits T helper functions primarily by affecting CD4,45RO+ cells, and (ii) this effect is probably mediated by contact inhibition in the early phase of T-B collaboration.

Evidence for Kupffer cell activation by burn injury and Pseudomonas exotoxin A

Postburn metabolic and immunological alterations may in part be due to translocation of gut exotoxin and endotoxin, which can result in tumour necrosis factor (TNF) and prostaglandin E (PGE) production by macrophages. We evaluated the effect of burn injury, plus exotoxin and endotoxin on TNF-alpha and PGE production by Kupffer cells, and peritoneal macrophages. Adult Wistar rats underwent 30 per cent TBSA burn or sham burn. Kupffer cells were harvested from rat livers and peritoneal macrophages from the abdominal cavity 24 h postburn. They were cultured overnight at 1 x 10(6) cells/ml and stimulated with saline, 5 micrograms/ml of Pseud. aeruginosa Exotoxin A (Exo-A), 5 micrograms/ml of Pseud. aeruginosa Endotoxin (Endo), Exo-A + Endo, or Exo-A + Endo + the PGE derivative 16,16 dimethyl-PGE (dPGE) (10 micrograms/ml). The supernatants were harvested after 4, 24 and 48 h of culture and assayed for TNF-alpha and PGE. Results showed that burn injury induced an increase in TNF-alpha and PGE production by Kupffer cells stimulated with Exo-A, Endo, and both Exo-A + Endo (P < 0.05). The release of TNF-alpha by Kupffer cells was downregulated by exogenous PGE (P < 0.05). The increased TNF-alpha production was inversely related to PGE levels. In conclusion, both burn injury and Exo-A potentiate the responsiveness of Kupffer cells and peritoneal macrophages to endotoxin as measured by the rate of production of TNF-alpha and PGE. PGE may locally downregulate the immune response by limiting Kupffer cells' and peritoneal macrophages' TNF-alpha production.

Alterations in intracellular lymphocyte metabolism induced by infection and injury

The effects of burn injury and sepsis on intracellular lymphocyte metabolism were evaluated using a rat model. Adult Lewis rats were subjected to a sham burn, a 30% full-thickness burn, or a 30% full-thickness burn which was infected with Pseudomonas aeruginosa. One week later the animals were sacrificed, and the splenic lymphocytes were harvested and cultured for 24 hr with mitogen stimulation. Lymphocytes from the burned-infected rats were found to utilize more glucose and certain amino acids than did lymphocytes obtained from the other two groups. Lymphocytes obtained from the burned-infected group had lower levels of the immunologically important enzyme, adenosine deaminase, than did the lymphocytes obtained from the other two groups. In summary, sepsis appears to alter a number of intracellular lymphocyte metabolic processes. These alterations may be found to be predictive of early sepsis.

Thromboxane/prostacyclin balance in type II diabetes: gliclazide effects

We studied serum thromboxane (TXB2), the prostacyclin metabolite, 6-keto-PGF1 (6KPGF1) glucose, insulin, and lipid/lipoprotein profiles in 27 patients with non-insulin-dependent diabetes mellitus (NIDDM) who were switched from therapy with glibenclamide (GLB) (with [GLBH] or without phenformin) to gliclazide for 3 months. We found that therapy with gliclazide was followed by a decrease in serum TXB2 (281.8 +/- 128.3 to 149.1 +/- 77.0 mg/L, P less than .001) and an increase in serum 6KPGF1 (60.5 +/- 19.1 to 96.0 +/- 40.3 mg/L, P less than .001). This was accompanied by a decrease in total and low-density lipoprotein (LDL) cholesterol and an increase in high-density lipoprotein (HDL) cholesterol, within the HDL3 cholesterol fraction. These changes were seen despite the fact that neither fasting plasma glucose nor insulin changed with therapy. These findings suggest that gliclazide may have beneficial actions on cardiovascular risk factors in these NIDDM patients.

Antibody binding to a collagen type-II epitope gives rise to an inhibitory peptide for autoreactive T cells

It is well documented that antigen recognition by T cells requires small peptides which are generated by protein cleavage in antigen-presenting cells. These peptides have to associate with major histocompatibility complex (MHC) molecules in order to be recognized. An inhibitory peptide may bind to the same site of the MHC-encoded protein but is not recognized by the T cell. Here we describe a stimulatory and an inhibitory peptide sequence within human collagen type II (CII) as defined by means of the same autoreactive human T cell clone. Most interestingly, the inhibitory peptide is not generated by regular processing in peripheral blood mononuclear cells but only in the presence of an antibody that binds to the same domain and thereby seems to protect the inhibitory sequence. This finding may indicate that certain autoantibodies have the potential to block autoreactive T cells with specificity for a distinct epitope on the same antigen.

[Usefulness of transcutaneous gas monitoring during hemorrhagic shock]

This study was undertaken to confirm whether transcutaneous (tc) gas analysis during hemorrhagic shock could be used as an alternative to mixed venous gas analysis. Tc gases were measured and correlated with arterial and mixed venous gases in 10 anesthetized dogs during hemorrhagic shock and volume resuscitation. Throughout this experiment PtcO2 correlated well with PvO2 (r = 0.78, P less than 0.01), while PaO2 remained mostly constant, and PtcCO2 correlated well with PvCO2 (r = 0.82, P less than 0.01) rather than with PaCO2 (r = 0.63, P less than 0.01). A more detailed observation showed that during progressively decreased cardiac output, PtcO2 became lower than PvO2 and PtcCO2 became higher than PvCO2. We inferred from these observations that the changes of tc and mixed venous gases reflected those gases in tissues and that during severe shock maldistribution of peripheral blood flow prevented mixed venous gases from coming into equilibrium with tissue and tc gases. We conclude that the measurement of tc gases during shock is a more convenient and more reliable monitor of tissue gases than mixed venous analysis.

Specificity and T cell receptor β chain usage of a human collagen type II-reactive T cell clone derived from a healthy individual

Collagen type II (CII) is a cartilage-specific matrix compound well known as an inducer of an experimental, T cell-dependent autoimmune arthritis, a disease which shows some similarities to human rheumatoid arthritis. Here we report on an HLA-DR7-restricted human CD4 T cell clone (TC9), which was isolated from a healthy donor and recognizes human CII. After screening CNBr fragments of CII and tryptic fragments derived thereof, the T cell epitope could be mapped to amino acid residues 271-285 of the triple helical region of CII that are located within CNBr fragment 11 [alpha 1 (II) CB11]. This epitope was confirmed by a synthetic peptide stimulatory for TC9. The T cell receptor beta chain of TC9 was cloned using the polymerase chain reaction; it comprises V beta 6.7 and contains besides J beta 2.3 and C beta 2 an as yet undescribed sequence for the D segment.

Constituents of Dipterocarpaceae Resins. IV. Triterpenes of Shorea acuminata and S. resina-nigra

Application of N.M.R. methyl resonance data led to revision of the structures given to the two cis 2,3-diols resulting from osmium tetroxide oxidation of methyl oleana-2,12-dien-28-oate (10). 2α,3α-Dihydroxyolean-l2-en-28-oic acid (6a), a new natural product, occurs in Shorea acuminata resin. Other constituents are 2α-hydroxy-ursolic acid (14a), mangiferonic acid (15b), and asiatic acid (14c). S. resina-nigra contains β-amyrin (16a), ursolaldehyde (14f), and Ψ-taraxesterol(17a).