Cloning of hydrogenase genes and fine structure analysis of an operon essential for H2 metabolism in Escherichia coli

Escherichia coli has two unlinked genes that code for hydrogenase synthesis and activity. The DNA fragments containing the two genes (hydA and hydB) were cloned into a plasmid vector, pBR322. The plasmids containing the hyd genes (pSE-290 and pSE-111 carrying the hydA and hydB genes, respectively) were used to genetically map a total of 51 mutant strains with defects in hydrogenase activity. A total of 37 mutants carried a mutation in the hydB gene, whereas the remaining 14 hyd were hydA. This complementation analysis also established the presence of two new genes, so far unidentified, one coding for formate dehydrogenase-2 (fdv) and another producing an electron transport protein (fhl) coupling formate dehydrogenase-2 to hydrogenase. Three of the four genes, hydB, fhl, and fdv, may constitute a single operon, and all three genes are carried by a 5.6-kilobase-pair chromosomal DNA insert in plasmid pSE-128. Plasmids carrying a part of this 5.6-kilobase-pair DNA (pSE-130) or fragments derived from this DNA in different orientations (pSE-126 and pSE-129) inhibited the production of active formate hydrogenlyase. This inhibition occurred even in a prototrophic E. coli, strain K-10, but only during an early induction period. These results, based on complementation analysis with cloned DNA fragments, show that both hydA and hydB genes are essential for the production of active hydrogenase. For the expression of active formate hydrogenlyase, two other gene products, fhl and fdv are also needed. All four genes map between 58 and 59 min in the E. coli chromosome.

Inhibition of lens-aldose reductase activity by brazilin and haematoxylin

Brazilin and haematoxylin, plant pigments, were examined for their effects on the Bovine-Lens aldose reductase (LAR)-activity. About 50% inhibition was observed in a concentration of 10 (-4) M-brazilin and 10 (-4) M-haematoxylin, and above 95% inhibition was observed in a concentration of 10 (-3) M-brazilin and 10 (-3)M-haematoxylin. In order to determine the type of inhibition, kinetic studies were also conducted with brazilin and haematoxylin, in which both were found to be noncompetitive inhibitors.

Schizophrenia and cerebral laterality

Investigators have suggested that schizophrenic patients have reversals of abnormal structural abnormalities and abnormal left hemisphere function. The authors attempted to know of the pattern of cerebral asymmetry in schizophrenic patients and controls on the computerized tomography scans of thirty right-handed schizophrenic patients and thirty right-handed control subjects. Compared to thirty right-handed controls, the schizophrenic patients had a significantly increased frequency of frontal and occipital reversals. This result suggests that reversals of neuroanatomical asymmetries, and by implicating the abnormalities of lateralization, are relevant to some schizophrenics. Statistics were done by the Chi square method.

High-level expression of M13 gene II protein from an inducible polycistronic messenger RNA

Bacteriophage M13 gene II has been cloned in the plasmid expression vector pING1 and thereby placed under the control of the inducible araB promoter of Salmonella typhimurium. Upon induction with arabinose, gene II is transcribed as part of a polycistronic messenger RNA which initiates at the araB promoter. Subsequent translation of this message results in the coordinate, high-level expression of several proteins, including the gene II protein. Using this expression system, we have been able to overproduce gene II protein to a level of almost 15% of the total protein in Escherichia coli cells, thus providing an abundant source for its purification.

Glycosylation of lens proteins in senile cataract and diabetes mellitus

We have investigated glycosylation of lens proteins in diabetic and non-diabetic senile cataract patients. Our study reveals that glycosylation of lens cortical proteins, but not of nuclear proteins, is significantly higher in diabetic patients with senile cataract. This finding serves to clarify the confusion over glycosylation of lens proteins as it relates to diabetes mellitus and further contributes to an understanding of glycosylation of lens tissues as a distinct posttranslational modification.

Multidrug treatment of advanced and recurrent endometrial carcinoma: a Gynecologic Oncology Group study

Patients (358) with advanced (FIGO stages III and IV) or recurrent endometrial cancer were treated with one of two regimens: 1) melphalan and 5-fluorouracil daily for four days, repeated every four weeks with megace daily for eight weeks and 2) adriamycin, 5-fluorouracil, and cyclophosphamide, intravenous bolus every 21 days with megace daily for eight weeks. All patients were randomized except for 63 with known cardiac disease who were assigned to regimen 1 (to avoid adriamycin) and studied separately. Stratification was effected for performance status, history of previous progestational therapy, presence or absence of measurable disease, and stage of disease. The objective response rate in those with measurable disease was 36.8% in both groups; 36.8% of each group had stable disease, and only 26.4% progressed on treatment. Response was unaffected by site of recurrence, time to first recurrence, presence or absence of previous treatment by progestational or radiation therapy, or age. Grade of tumor and performance status did affect response, although 44 of 57 objective responders had undifferentiated tumors. The two combinations achieved response rapidly, required careful supervision, and were especially useful in treating patients with usually poor prognostic features.

Genetic characterization of Salmonella typhimurium LT2 ara mutations

Seventeen independently isolated L-arabinose utilization-deficient mutants of Salmonella typhimurium LT2 were characterized. Four complementation groups (araA, araB, araC, and araD) were identified and were equivalent to the same genes in the ara system in Escherichia coli. The order of the four genes was determined to be araD-araA-araB-araC-leu. Two transcription units were found: the araBAD operon was transcribed counterclockwise, and the araC gene was transcribed clockwise.

The effects of in vivo hydrocortisone on lymphocyte-mediated cytotoxicity

To examine the effects of in vivo hydrocortisone sodium succinate (HC) on natural killer (NK) cell and antibody-dependent cellular cytotoxicity (ADCC), 11 normal adults received a single intravenous bolus of 400 mg hydrocortisone. Lymphocytes were tested for NK activity and ADCC using 51chromium (51Cr)-release and single cell cytotoxicity assays against Molt-4 and sensitized RL O leads to target cells, respectively. Four hours after injection, both NK and ADCC activity were transiently increased in the 51Cr-release system (P less than 0.05). At 4 hours, there was a twofold increase in the relative frequency of potentially cytotoxic target binding cells (P less than 0.001) but the absolute number of these cells did not change (P less than 0.1). However, the percentage lysis of bound targets at 4 hours was not altered (P greater than 0.1). These data suggest that: 1) lymphocytes participating in NK and ADCC reactions are refractory to the kinetic and functional effects of HC; 2) the increased lytic activity observed at 4 hours is due to a selective depletion of noncytotoxic cells from the circulation; and 3) NK and ADCC activity did not differ in their responses to HC.

Glycosylation in vivo of human lens capsule (basement membrane) and diabetes mellitus

Glycosylation represents a nonenzymatic posttranslational modification of some proteins in vivo. We have investigated possible glycosylation, in vivo, of human lens capsule (basement membrane of lens epithelium) using a colorimetric method. Our study reveals, for the first time, in vivo glycosylation of human lens capsule. Furthermore, the glycosylation of the lens capsule in the diabetics (57.30 +/- 11.26 n moles/mg. protein) is found to be significantly greater than that in their nondiabetic counterparts (29.11 +/- 4.90 n moles/mg. protein) (p less than 0.0005). The present observation represents the first example of increased glycosylation of a basement membrane in the diabetic patients as compared to the nondiabetic controls.

Effects of aerobic and anaerobic shock on catabolite repression in cyclic AMP suppressor mutants of Escherichia coli

Cultures of Escherichia coli K-12 grown on glucose or gluconate under aerobic conditions exhibited catabolite repression of beta-galactosidase synthesis. Depression occurred when these cultures were subjected to anaerobic shock. These states of repression and depression were found to be associated with low and high differential rates of cyclic AMP synthesis, respectively. This observation is consistent with the view that cyclic AMP plays a central role in the catabolite repression phenomenon. We report here, however, that identical stages of repression and derepression occur in mutant strains possessing cya crp(Csm) genotypes and therefore unable to synthesize cyclic AMP. These results suggest that cyclic AMP is not the sole regulator involved in catabolite repression.

Placental proteins (human chorionic gonadotropin, human placental lactogen, pregnancy-specific beta 1-glycoprotein, and placental protein 5) in seminal plasma of normal men and patients with infertility

Placental proteins, including human chorionic gonadotropin (hCG), human placental lactogen (hPL), pregnancy-specific beta 1-glycoprotein (SP1), and placental protein 5 (PP5) have been detected in human seminal plasma of 20 normal men and 42 patients with infertility. Levels of hPL, SP1, and PP5 were similar in these groups. There were significantly higher levels of hCG in subjects with normal sperm counts than in those with oligospermia or azoospermia. The levels of PP5 in seminal plasma showed an association with sperm motility, suggesting that PP5 may have a significant biologic function in the maintenance of sperm motility.

Mechanisms of human cell-mediated cytotoxicity. III. Dependence of natural killing on microtubule and microfilament integrity

To date, the mechanisms of human natural killer (NK) cell activity have been poorly defined. Since microtubules and microfilaments are important in many non-NK leukocytic processes, the potential roles of these cellular elements in natural killing were assessed in simultaneously performed 51-chromium-release microcytotoxicity and single cell cytotoxicity assays. The microtubule inhibitors colchicine, vincristine, and vinblastine suppressed chromium-release in a concentration-dependent fashion. This suppression could be prevented by the promoters of microtubule assembly, deuterium oxide and cyclic GMP. Microtubule inhibitors did not affect the binding of natural killer cells to target cells but did suppress the lysis of bound targets. The "recycling" of natural killer cells to repeat the lytic sequence was not altered by microtubule-disrupting agents. Cytochalasin B, a microfilament inhibitor, induced dose-dependent suppression of lytic activity in the chromium-release assay. Concentrations of cytochalasin B greater than 2 micrograms/ml prevented the binding of effector cells to target cells. Concentrations of cytochalasin B less than 2 micrograms/ml depressed killing in the chromium-release assay but did not alter target cell binding or the lysis of bound targets indicative of an inhibition of effector cell recycling. Concentrations of cytochalasin B greater than 2 micrograms/ml did not affect the lysis of bound targets once binding had occurred. The roles of microtubules and microfilaments in the lytic sequence can therefore be subdivided based on these data: 1) the binding of natural killer cells to target cells in dependent on microfilaments; 2) the lysis of bound targets requires microtubule assembly; and 3) the subsequent post-lytic recycling of natural killer cells necessitates a intact microfilament system.

Mechanisms of human cell-mediated cytotoxicity. III. Dependence of natural killing on microtubule and microfilament integrity

To date, the mechanisms of human natural killer (NK) cell activity have been poorly defined. Since microtubules and microfilaments are important in many non-NK leukocytic processes, the potential roles of these cellular elements in natural killing were assessed in simultaneously performed 51-chromium-release microcytotoxicity and single cell cytotoxicity assays. The microtubule inhibitors colchicine, vincristine, and vinblastine suppressed chromium-release in a concentration-dependent fashion. This suppression could be prevented by the promoters of microtubule assembly, deuterium oxide and cyclic GMP. Microtubule inhibitors did not affect the binding of natural killer cells to target cells but did suppress the lysis of bound targets. The "recycling" of natural killer cells to repeat the lytic sequence was not altered by microtubule-disrupting agents. Cytochalasin B, a microfilament inhibitor, induced dose-dependent suppression of lytic activity in the chromium-release assay. Concentrations of cytochalasin B greater than 2 micrograms/ml prevented the binding of effector cells to target cells. Concentrations of cytochalasin B less than 2 micrograms/ml depressed killing in the chromium-release assay but did not alter target cell binding or the lysis of bound targets indicative of an inhibition of effector cell recycling. Concentrations of cytochalasin B greater than 2 micrograms/ml did not affect the lysis of bound targets once binding had occurred. The roles of microtubules and microfilaments in the lytic sequence can therefore be subdivided based on these data: 1) the binding of natural killer cells to target cells in dependent on microfilaments; 2) the lysis of bound targets requires microtubule assembly; and 3) the subsequent post-lytic recycling of natural killer cells necessitates a intact microfilament system.

Abnormal natural killer cell activity in systemic lupus erythematosus: an intrinsic defect in the lytic event

The natural killer (NK) cell activity in fifteen systemic lupus erythematosus (SLE) patients was investigated by employing 51-chromium- (51Cr) release microcytotoxicity and single cell cytotoxicity assays against K562 target cells. Although the SLE patients as a group had depressed NK function in the 51Cr-release assay compared to normal subjects (p less than 0.005), those with clinically active disease displayed the greatest impairment in this activity (p less than 0.001). Active SLE patients were deficient in overall NK activity (Vmax) (p less than 0.005) but had normal percentages of potentially cytotoxic target binding cells (TBC). These TBC, however, were unable to normally kill bound target cells (p less than 0.01), which is indicative of a deficiency of "active" NK cells (p less than 0.005). Those NK cells with intact cytotoxic capabilities could "recycle" and repeat the lytic sequence normally. Exposure of normal lymphocytes to SLE sera did not impair any phase of NK function. These studies indicate that defective NK activity in SLE is secondary to an abnormality in the lytic event itself and is not due to a deficiency of NK cells, an abnormality in target binding, or an inability of NK cells to lyse multiple targets. Additionally, serum factors do not appear to play a major etiologic role in the cytotoxic abnormalities of these patients.

Abnormal natural killer cell activity in systemic lupus erythematosus: an intrinsic defect in the lytic event

The natural killer (NK) cell activity in fifteen systemic lupus erythematosus (SLE) patients was investigated by employing 51-chromium- (51Cr) release microcytotoxicity and single cell cytotoxicity assays against K562 target cells. Although the SLE patients as a group had depressed NK function in the 51Cr-release assay compared to normal subjects (p less than 0.005), those with clinically active disease displayed the greatest impairment in this activity (p less than 0.001). Active SLE patients were deficient in overall NK activity (Vmax) (p less than 0.005) but had normal percentages of potentially cytotoxic target binding cells (TBC). These TBC, however, were unable to normally kill bound target cells (p less than 0.01), which is indicative of a deficiency of "active" NK cells (p less than 0.005). Those NK cells with intact cytotoxic capabilities could "recycle" and repeat the lytic sequence normally. Exposure of normal lymphocytes to SLE sera did not impair any phase of NK function. These studies indicate that defective NK activity in SLE is secondary to an abnormality in the lytic event itself and is not due to a deficiency of NK cells, an abnormality in target binding, or an inability of NK cells to lyse multiple targets. Additionally, serum factors do not appear to play a major etiologic role in the cytotoxic abnormalities of these patients.

Competitive rate nephelometric immunoassay for determination of theophylline, phenobarbital, and dilantin in serum

The theophylline, phenobarbital and dilantin were measured in serum by rate nephelometric immunoassay with the Beckman Immunochemistry System (ICS, Beckman Inc. Brea., CA 92621). The procedures required less than three minutes after proper calibration and dilution, and only 42 microliters of serum theophylline and 100 microliters of serum for phenobarbital and dilantin per determination. It is simple and needs only pipetting and dilution with automatic dispenser and diluter. Day to day variation was determined by analyzing on 30 days two control sera containing theophylline level I (12 micrograms/ml 18-micrograms/ml) and level II (30 micrograms-38 micrograms/ml). The average theophylline level I concentration was 14.5 micrograms/ml, with a standard deviation of 0.70 micrograms/ml, and a coefficient of variation of 4.8%. The average theophylline level II concentration was 32.2 micrograms/ml, with a standard deviation of 1.89 micrograms/ml, and a coefficient of variation of 5.9%. Results attained in patients were compared with results of enzyme immunoassay procedure (EMIT, Syva Corp.). For theophylline, r-0.957, for phenobarbital, r=0.936, and for dilantin, r=0.972.