Efficient production of transgenic melon via Agrobacterium-mediated transformation.

Oriental melon (Cucumis melo L. var. makuwa) is an important fruit for human consumption. However, this plant species is one of the most recalcitrant to genetic transformation. The lack of an efficient in vitro system limits the development of a reproducible genetic transformation protocol for Oriental melon. In this study, an efficient transgenic production method for Agrobacterium-mediated transformation using cotyledon explants of Oriental melon was developed. Cotyledon explants were pre-cultivated for two days in the dark, and the optimal conditions for transformation of melon were determined to be a bacteria concentration of OD600 0.6, inoculation for 30 min, and two days of co-cultivation. Transgenic melon plants were produced from kanamycin-resistant shoots. A total of 11 independent transgenic plants were regenerated with a transformation efficiency of 0.8% of the inoculated explants. The transgenic plants were phenotypically normal and fully fertile, which might be a consequence of the co-cultivation time.

Characterization and heterologous expression of a novel lysophospholipase gene from Antrodia cinnamomea.

AIMS: A novel lysophospholipase (LysoPL) from the basidiomycetous fungi Antrodia cinnamomea named ACLysoPL was cloned, heteroexpressed in Escherichia coli and characterized. METHODS AND RESULTS: The gene encoding ACLysoPL was obtained from expressed sequence tags from A. cinnamomea. The full length of this gene has a 945 -bp open reading frame encoding 314 amino acids with a molecular weight of 35.5 kDa. ACLysoPL contains a lipase consensus sequence (GXSXG) motif and a Ser-His-Asp catalytic triad. A putative peroxisomal targeting signal type 1 was found in the C-terminal. Heterologous expression of ACLysoPL in E. coli showed that the enzyme preferentially hydrolyses long-chain acyl esterases at pH 7 and 30 degrees C. ACLysoPL is a psychrophilic enzyme about 40% of whose maximum activity remained at 4 degrees C. The LysoPL activities with lysophospholipids as substrate were analysed by gas chromatography/mass spectrometry. CONCLUSION: We have identified and characterized a gene named ACLysoPL encoding a protein performing LysoPL and esterase activities. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first LysoPL of A. cinnamomea identified and characterized at the molecular level.

Studies of optimum conditions for covalent immobilization of Candida rugosa lipase on poly(gamma-glutamic acid) by RSM.

Poly(gamma-glutamic acid) (gamma-PGA) is a material of polymer. Immobilization of Candida rugosa lipase (Lipase AY-30) by covalent binding on gamma-PGA led to a markedly improved performance of the enzyme. Response surface methodology (RSM) and 3-level-3-factor fractional factorial design were employed to evaluate the effects of immobilization parameters, such as immobilization time (2-6h), immobilization temperature (0-26 degrees C), and enzyme/support ratio (0.1-0.5, w/w). Based on the analysis of ridge max, the optimum immobilization conditions were as follows: immobilization time 2.3h, immobilization temperature 13.3 degrees C, and enzyme/support ratio 0.41 (w/w); the highest lipase activity obtained was 1196 U/mg-protein.

Conformations of lysine-sensitive aspartokinase.

1. The technique of differential thermal and proteolytic inactivation has been employed as a conformational probe for the lysine-sensitive aspartokinase (EC 2.7.2.4) of Escherichia coli B. 2. L-Amino acid inhibitors of this enzyme each induce a characteristic enzyme conformation. This is evidenced by rates of thermal and proteolytic inactivation and Arrhenius activation energies for thermal inactivation which are characteristic of the amino acid present. 3. Phenylalanine and leucine binding are mutually exclusive as evidenced by competitive behavior in thermal inactivation experiments, suggesting a hydrophobic amino acid binding site with broad specificity. 4. The phenylalanine-dependent conformation and the leucine-dependent conformation differ considerably. In comparison with the native enzyme, the former is more labile to proteolysis by trypsin whereas the latter is more stable. First-order rate constants for thermal inactivation of the phenylalanine- and leucine-dependent conformations are, respectively, about one-half and one-tenth that of the native enzyme. 5. Items 3 and 4 taken together suggest that the conformations are ligand induced and do not arise via ligand stabilization of spontaneously arising conformers.

Crystallization and preliminary X-ray crystallographic analysis of arylesterase from Vibrio mimicus.

Single crystals of arylesterase (EC 3.1.1.2) from Vibrio mimicus have been obtained from ammonium sulfate as a precipitant at room temperature for 2 months. The present crystals diffract up to 2.2 A resolution and belong to monoclinic space group P2(1). The cell dimensions are a = 55.65(1) A, b = 53.46(1) A, c = 65.79(1) A, and beta = 106.54(1) degrees. There are two molecules of molecular weight 22 kDa in an asymmetric unit with a solvent content of 43%.

Prolongation of rat cardiac allograft survival by treatment with prostacyclin or aspirin during acute rejection.

Hearts taken from DA (RT1a) rats were transplanted heterotopically to PVG (RT1c) rats of the same sex (day 0). On day 1 or on day 5 rats were treated with prostacyclin (PGI2), 250 ng/kg/min, by continuous infusion of alkaline solution into the inferior vena cava until the time of rejection. Controls received glycine buffer infusion alone, from day 1 or day 5. Cessation of palpable graft beat was taken as the end point of rejection. When PGI2 was infused from day 5 median graft survival time was prolonged from a control of 7.8 days to 9.3 days (P less than 0.05). When PGI2 was infused from day 1, graft survival time was prolonged from a control of 7.4 days to 8.6 days (P less than 0.05). Other groups of rats were treated from day 1 or from day 5 with aspirin (acetylsalicylic acid), 200 mg/kg/day, by 8-hourly subcutaneous injection in saline. Control groups received saline alone. When aspirin was given from day 5, graft survival time was prolonged from a control of 7.3 days to 9.5 days (P less than 0.05). When aspirin was given from day 1 graft survival time was prolonged from a control of 7.2 days to 14.9 days (P less than 0.01), and in two cases this led to very prolonged survival. Histological examination at the time of rejection showed lymphocyte and neutrophil infiltration to be much more prominent than vessel occlusion in all groups. These results imply that PGI2 and aspirin may be beneficial to graft survival in acute rejection, but this is not due to reduced occlusion of blood vessels by platelets.

Effect of pretransplant stored donor-specific blood transfusions on early renal allograft survival in one-haplotype living related transplants.

The effect of pretransplant stored donor-specific blood transfusions (DSBTs) on early renal allograft survival in 37 consecutive one-haplotype living related donor (LRD) transplants (group B) was compared with a similar consecutive series of 38 one-haplotype LRD recipients (group A) who did not receive DSBTs. All transplant recipients in both groups were treated with identical immunosuppressive protocols using azathioprine and prednisone. Forty patients received pretransplant DSBTs and three of these patients (8%) developed cytotoxic antibodies to their prospective donors. Neither hyperacute rejection nor hepatitis occurred in group B patients following DSBTs. One group B patient experienced a technical graft loss on the 1st postoperative day and was excluded from the rejection data. Graft survival at 3 and 6 months was 100 and 90% in group B recipients and 68% in group A recipients. All 12 group A graft failures resulted from acute nonreversible rejection episodes occurring during the first 3 months post-transplant. The three group B graft failures occurring at 6 months were attributable to chronic vascular rejection. Chronic rejection of the renal allograft was histologically documented in six group A and five group B patients by 6 months post-transplant. The use of stored donor blood offered a simple and easily monitored method of administering pretransplant DSBTs that was convenient to the donor and recipient. The administration of DSBTs did not appear to be harmful to the recipient. In fact, the use of pretransplant stored DSBTs in one-haplotype LRD renal transplantation appeared to improve the prospects of early graft survival in our experience.

Renal fibromuscular hyperplasia associated with subarachnoid hemorrhage from a berry aneurysm: a case report.

An 11-year-old girl with renal artery fibromuscular hyperplasia and a berry aneurysm of the anterior communicating artery with subarachnoid haemorrhage is reported. She presented with subarachnoid hemorrhage and was shown to have hypertension attributable to unilateral renal artery fibromuscular hyperplasia. Cerebral angiography showed an aneurysm of the anterior communicating artery. The aneurysm was not treated surgically, but control of the hypertension was obtained by renal revascularisation with an aortorenal graft of saphenous vein. The patient remained well subsequently, and follow-up angiography demonstrated virtual disappearance of the aneurysm and also a functioning aortorenal graft.

Cytokine secretion in mixed lymphocyte culture: a prognostic indicator of renal allograft rejection in addition to HLA mismatching.

We have previously demonstrated significant inter-individual variations in cytokine protein secretion between normal individuals and patients prior to renal transplantation. In this study, pre-transplant patient vs. donor mixed lymphocyte cultures (MLC) were set up between 57 renal allograft patient/donor pairs, and secretion of cytokine protein (IL-2, IL-4, IL-6, IL-10 and IFN-gamma) into the culture supernatant measured by ELISA. Significant inter-individual variations in protein secretion in MLC were observed for all cytokines studied. Univariate analysis demonstrated that high levels of IFN-gamma and IL-10 in MLC and spontaneous IL-4, together with female donor sex and a high degree of HLA mismatching (especially HLA-DR) were significantly associated with rejection. However, multivariate analysis revealed the greatest risk of rejection (RR = 25.5, P = 0.003) was associated with a combination of high IL-10 secretion in MLC and mismatching for at least four HLA antigens (HLA-A, -B and -DR). It remains to be determined whether cytokine secretion in MLC is linked to cytokine gene polymorphisms. In future, assays for measuring either cytokine secretion or genetic polymorphisms may prove to be useful in aiding donor selection and tailoring immunosuppressive therapy.

A study of cytokine gene polymorphisms and protein secretion in renal transplantation.

Although there is evidence that cytokine gene polymorphisms are associated with varying quantities of cytokine protein production, the exact role of these polymorphisms in allograft rejection remains unclear. In a previous study, we demonstrated a significant association between high IL-10 secretion in mixed lymphocyte culture (MLC), together with HLA mismatching for at least 4-6 antigens, with the occurrence of acute rejection following renal transplantation. We, therefore, wished to ascertain whether cytokine gene polymorphisms are associated with varying levels of protein secretion and/or allograft rejection in the same group of patients. Cytokine protein secretion in MLC for IL-4, IL-6, IL-10 and IFN-gamma was measured by ELISA in 49 patient-donor pairs. Protein secretion for the above cytokines was also measured in phytohaemagglutinin (PHA) stimulated cultures in 30 normal controls. In both patient and control groups, single nucleotide polymorphism analysis for IL-4 G(-590)T, IL-6 G(-174)C, IL-10 G(-1082)A, IL-10 C(-819)T, IL-10 C(-592)A, TNF-alpha G(-308)A and microsatellite analysis for IFNG (CA repeat) was performed. No correlation was found between cytokine gene polymorphisms and cytokine protein secretion in either mitogen stimulated cultures (control group) or MLC (patient group). In addition, no correlation was demonstrated between cytokine gene polymorphisms and renal allograft rejection.

The incidence of HLA antigens in black primary open-angle glaucoma patients.

We compared the HLA antigen frequencies in black primary open-angle glaucoma patients to those in black non-glaucomatous patients; normal, nondiseased black persons; and nondiseased North American blacks. We found no statistically significant alteration in HLA antigen frequencies in black open-angle glaucoma patients as compared to a control population.

Extracerebral hematoma in association with dural substitute.

The authors present a patient who developed an acute hemorrhage around a Silastic dural substitute 13 weeks after excision of a meningioma and implantation of the graft. The relevant literature is reviewed.

Pleomorphic xanthoastrocytoma. Report of four cases.

Four cases of pleomorphic xanthoastrocytoma (PXA), a low-grade leptomeningeal glioma with a reported favorable prognosis affecting young patients, are reported together with a discussion and review of management and prognosis. A literature review has confirmed a favorable prognosis in at least 50% of patients with this disorder. Seventeen of 35 reported patients are still alive and often seizure-free for a mean period of 7.4 years (range 2 to 18 years) after diagnosis. Five patients have died within 2 years and four between 9 and 25 years after diagnosis of PXA. In some cases in which death followed shortly after diagnosis, there may have been histological confusion between PXA and a malignant glioma with heavily lipidized tumor cells. Nonetheless, transformation of PXA into a malignant astrocytoma or glioblastoma with eventual death may occur many years after initial diagnosis. From the currently reported cases it does not appear possible on clinicopathological grounds to predict which patients will have a favorable prognosis. Optimal management of PXA seems to be primary surgical resection with later surgery for residual or recurrent tumor. The role of radiotherapy in the management of PXA is at this time uncertain.

Additional effects of monovalent cations on the lysine-sensitive aspartokinase of E. coli B.

The apparent specificity of activation of lysine-sensitive aspartokinase (E.C.2.7.2.4) from E. coli by monovalent cations differs depending on the assay used and on the Mg2+ concentration. Activity is nearly absolutely dependent on and is highly specific for a monovalent cation in the aspartate semialdehyde dehydrogenase coupled assay or the adenosine triphosphate-adenosine diphosphate exchange assay. Little specificity for monovalent cations is observed using the aspartyl hydroxamate assay. Activation and specificity are also altered by Mg2+ concentrations at a constant 5 mM nucleotide concentration. At a low (1.25 or 1.6 mM)Mg2+ concentration, monovalent cation activation and specificity are nearly absolute. Less dependence on monovalent cations and less specificity are observed at a higher Mg2+ concentration (6 mM). Li+ inhibits aspartokinase competitively with respect to either K+ or NH4+. Monovalent cations are also thermoprotective and differential thermal inactivation experiments at 56 degrees C reveal that NH4+ and K+, either of which will produce maximum catalytic activity, interact differently with aspartokinase. K+ interacts with positive cooperativity, whereas NH4+ does not. K+, NH4+, and Na+ are about equally effective in enhancing the dissociation of the aspartokinase-aspartylphosphate complex. Li+ is less effective.

Lipase-catalyzed synthesis of fatty acid diethanolamides.

Diethanolamides are nonionic emulsifiers widely used in industries such as cosmetics and as corrosion inhibitors. Candida antarctica lipase (Novozym 435) was used to catalyze the amidation of various fatty acids with diethanolamine. Contents of fatty acids, metal ions, and water affected the yields of diethanolamides. Hexanoic acid was the best substrate among all acyl donors. Yields of hexanoyl diethanolamide (HADEA), lauroyl diethanolamide (LADEA), and oleoyl diethanolamide (OADEA), obtained after 24 h of lipase-catalyzed reaction at 50 degrees C and 250 rpm with 90 mM fatty acid and 360 mM diethanolamine in acetonitrile, were 76.5, 49.5, and 12.1%, respectively. Addition of 1 mM metal salts increased the yields of HADEA and LADEA. Kinetic analysis showed that the yields of HADEA and LADEA in lipase-catalyzed reactions were largely associated with the rate of the forward reaction constant k(1). Anhydrous enzyme was found to be the best for the amidation reaction. Study on the enzyme operational stability showed that C. antarctica lipase retained 95 and 85% of the initial activity for the syntheses of HADEA and LADEA, respectively (even after repeated use for 10 days). The reaction runs smoothly without the use of hazardous reactants, and the developed method is useful for the industrial application.

Synthesis of fatty acid esters by recombinant Staphylococcus epidermidis lipases in aqueous environment.

Various flavor esters were obtained by using recombinant lipases from Staphylococcus epidermidis as a catalyst in an aqueous environment. These esters were enzymatically synthesized to overcome the problems associated with chemical processes. This study showed that the S. epidermidis lipases could catalyze ester synthesis from decyl alcohol and fatty acids of different chain length. The wild-type and mutant lipases (M419A and V649I) could efficiently catalyze the synthesis of decyl alcohol esters of unsaturated fatty acids. In contrast, the yield of decyl laurate was better by wild-type and mutant enzyme V6491, but mutant enzyme M419A only favored the synthesis of decyl myristate. The esterification of oleic acid and various carbon-chain-length alcohols from ethanol to hexadecanol increased up to decanol by wild-type and M419A mutant enzymes and reached an optimum for dodecanol by V6491 mutant enzyme. The enzyme is potentially useful in food industries such as dairy product flavoring.

Cloning and expression of a cDNA coding for catalase from zebrafish (Danio rerio).

A full-length complementary DNA (cDNA) clone encoding a catalase was amplified by the rapid amplication of cDNA ends-polymerase chain reaction (RACE-PCR) technique from zebrafish (Danio rerio) mRNA. Nucleotide sequence analysis of this cDNA clone revealed that it comprised a complete open reading frame coding for 526 amino acid residues and that it had a molecular mass of 59 654 Da. The deduced amino acid sequence showed high similarity with the sequences of catalase from swine (86.9%), mouse (85.8%), rat (85%), human (83.7%), fruit fly (75.6%), nematode (71.1%), and yeast (58.6%). The amino acid residues for secondary structures are apparently conserved as they are present in other mammal species. Furthermore, the coding region of zebrafish catalase was introduced into an expression vector, pET-20b(+), and transformed into Escherichia coli expression host BL21(DE3)pLysS. A 60-kDa active catalase protein was expressed and detected by Coomassie blue staining as well as activity staining on polyacrylamide gel followed electrophoresis.

Characterization of the dimer-monomer equilibrium of the papaya Copper/Zinc superoxide dismutase and its equilibrium shift by a single amino acid mutation.

The coding region of the copper/zinc superoxide dismutase (Cu/Zn SOD) cDNA from papaya fruit, Carica papaya L. cv. Tainong 2, was cloned into an expression vector, pET-20b(+). The Cu/Zn SOD was expressed in Escherichia coli and purified by His-tag technique. Two active forms of the enzyme (30% dimer and 70% monomer) in equilibrium were observed. The activity of the dimeric enzyme was higher than that of the monomeric form. The thermal inactivation rate constant K(d) values calculated for the dimer and monomer at 90 degrees C were -0.0203 and -0.0216 min(-1), and the half-lives for inactivation were 41.9 and 31.8 min, respectively. This indicated that the dimeric enzyme was more stable than its monomeric form. The dimerization of the enzyme was inhibited under acidic pH (below 3.0) or imidazole buffer (above 0.5 M), whereas it was not affected under alkaline pH (above 9.0). Both activity and forms of the enzyme were not affected by 1-4% SDS. Furthermore, the dimeric enzyme was much more resistant to proteolytic attack after 3 h of incubation at 37 degrees C with trypsin or chymotrypsin. In addition, mutation of the papaya Cu/Zn SOD at position 48 from Leu to Phe (L48F) affected the association of monomer, whereas a mutant with Lys substitution (L48K) at the same position tended to dissociate into monomeric form.

Treatment of end-stage renal disease by transplantation: clinical results with 111 cases.

The efficacy of renal transplantation for patients with end-stage renal disease was reviewed in 108 patients receiving 111 transplants followed for an average of two and one-half years after transplantation. Overall patient survival decreased 10 per cent per year from 90 per cent after the first year to 70 per cent at three years. Kidney survival was slightly less, with a similar pattern. Patients with better tissue matches and living related donor allografts had fewer and less severe rejections and better ultimate function than did patients with poor tissue matches and cadaver allografts. However, a significant number of patients with poor tissue matches and cadaver allografts had excellent results. Eighty-six per cent of all survivors with functioning kidneys had serum creatinines of 2.0 mg./100 ml. or below. Mortality was associated primarily with sepsis from a variety of bacterial, fungal, viral and protozoan organisms often associated with other complications such as rejection or gastrointestinal bleeding. Recipients over the age of 40 were in a higher risk group. Rejection per se, however, played a minor role. Urological and skeletal complications were a major source of morbidity but were not associated with mortality.

HLA typing.

I present an overview of HLA typing, a method of evaluating donor-recipient compatibility. The major histocompatibility system in man, the HLA region, considered to control the immunologic response to transplantation and perhaps to certain diseases, is discussed in relation to chromosomal location, chromosomal mapping, association with other markers, nomenclature of the gene products (the HLA antigens), inheritance of the HLA antigens, and methods of determining these antigens. Use of HLA typing is currently most applicable in the correlation of certain diseases with HLA antigen frequency, in evaluating donor-recipient pairs for renal and bone marrow transplantation and for transfusion of platelets and granulocytes and in paternity testing.