Isolation and properties of a blood coagulation factor X activator from the venom of king cobra (Ophiophagus hannah)

A specific blood coagulation factor X activator was purified from the venom of Ophiophagus hannah by gel filtration and two steps of FPLC Mono-Q column ion-exchange chromatography. It showed a single protein band both in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and alkaline polyacrylamide gel electrophoresis. The mol. wt was estimated to be 62,000 in non-reducing conditions and 64,500 in reducing conditions by SDS-PAGE. The isoelectric point was found to be pH 5.6. The enzyme had weak amidolytic activities toward CBS 65-25, but it showed no activities on S-2266, S-2302, thrombin substrate S-2238, plasmin substrate S-2251 or factor Xa substrate S-2222. It had no arginine esterase activity toward substrate benzoylarginine ethylester (BAEE). The enzyme activated factor X in vitro and the effect was absolutely Ca2+ dependent, with a Hill coefficient of 6.83. It could not activate prothrombin nor had any effect on fibrinogen and thus appeared to act specifically on factor X. The procoagulant activity of the enzyme was almost completely inhibited by serine protease inhibitors like PMSF, TPCK and soybean trypsin inhibitor; partially inhibited by L-cysteine. Metal chelator EDTA did not inhibit its procoagulant activity. These results suggest that the factor X activator from O. hannah venom is a serine protease.

Ischemic bowel secondary to angiocentric T-cell lymphoma of intestine: a case report

A case of intestinal angiocentric T-cell lymphoma is reported, occurring in a 72-year-old female who had suffered from poor appetite, body weight loss and abdominal pain for two months. Plain abdominal film revealed ileus, and she received laparotomy under the impression of ischemic bowel. Surprisingly, pathologic examination disclosed an angiocentric T-cell lymphoma of jejunum complicated with focal intestinal necrosis. This case emphasizes the angiocentric and angioinvasive character of some T-cell lymphomas. Angiocentric T-cell lymphoma must be considered as a possible cause of ischemic bowel.

Psoas abscess due to mucinous cystadenocarcinoma of the appendix: a case report

Psoas muscle abscess is an uncommon and challenging entity. The present report describes a 64-year-old man presenting with right flank mass. Abdominal computerized tomography showed a right psoas abscess. Extraperitoneal drainage was performed, and pathology revealed metastatic mucinous adenocarcinoma. After further study, laparotomy and right hemicolectomy were performed under the impression of colon cancer. The final pathology showed mucinous cystadenocarcinoma of appendix. The literature about the etiology, diagnosis and treatment of psoas abscess are reviewed. Additionally, the treatment and prognosis for mucinous cystadenocarcinoma of the appendix are noted.

Morphological remodeling of the motor end plate in rat soleus muscle after limb immobilization by casting

The effects of muscular inactivity on motor end plate(MEP) structures of the rat soleus muscle were studied qualitatively and quantitatively. Eight adult rats were divided into two equal groups. One group had their right hind limbs immobilized by application of plaster casts. After 14 days in the casts, the soleus muscles of all the animals were removed. Three groups of MEPs were analyzed to compare their structural characteristics: the immobilized group (the MEPs of the casted soleus muscles), the contralateral group (the MEPs of soleus muscles which were in legs contralateral to the casted legs), and the control group (the MEPs of normal soleus). The MEPs were examined in a teased preparation of soleus muscles stained by silver-impregnation. The architecture of the MEPs was measured by an "AMS VIDS III Image Computerized System" which was mounted with a light microscope for morphological analysis. The measured parameters were the structural elements of MEPs. The results of the present study showed that: MEPs of the immobilized group exhibited more complex and highly branches structures than the other two groups. The total number of branches and the length of the terminal perimeter in the immobilized group increased significantly. Concomitantly, the amount of swollen terminals of this group were obviously larger than in the other two groups. The results demonstrated that the muscular inactivity of the casted limbs produced denervation-like changes at branches of nerve terminals. These changes were the result of altered muscular function, and led to structural remodeling of MEPs of the muscles.

Immortalized murine striatal neuronal cell lines expressing dopamine receptors and cholinergic properties

Immortalized hybrid cells were generated by somatic cell fusion of 18-d-old embryonic corpus striatum of the mouse strain C57BL/6J with the N18TG2 neuroblastoma. One of the cell populations obtained was treated with a combination of 1 mM n-butyric acid and 10 microM SKF 38393 (a specific D1 agonist), and a surviving cell population (E1X) was subcloned. Twenty-seven monoclonal cell lines were obtained and screened for the expression of striatal-specific characteristics including gamma-aminobutyric acid (GABA), choline acetyltransferase (ChAT), acetylcholine (ACh), mRNA for specific dopamine receptors, and dopamine- and adenosine 3':5'-monophosphate-regulated phosphoprotein, M(r) 32,000 (DARPP-32), and functional D1 and D2 dopamine receptors. Neither the parent hybrid cell population (E1X) nor any of the monoclonal cell lines examined expressed GABA levels significantly different than that of the N18TG2 parent neuroblastoma cells (1.36 +/- 0.07 micrograms/mg protein). The range of ChAT activity in the monoclonal hybrid cell lines was 5.5 +/- 0.3 to 921.3 +/- 97.4 pmol/min/mg protein. Two of the cell lines expressing ChAT activity (X52 and X58) contained ACh (49.64 +/- 4.23 and 1.78 +/- 0.07 ng/mg protein, respectively). The neuronal origin of four of the monoclonal hybrid lines was shown by their immunoreactivity, following differentiation with 10 microM forskolin, to neurofilament protein, a neuron-specific marker. The monoclonal hybrid cell lines, but not the N18TG2 neuroblastoma, were shown to express an array of D1, D2, and D5 receptor mRNA as well as DARPP-32 mRNA. Two monoclonal cell lines expressed D1 receptor binding sites (X57, 29.2 +/- 4.5 fmol/mg protein and X62, 43.8 +/- 6.8 fmol/mg protein) which mediated the stimulation of adenylate cyclase activity. One cell line, X58, expressed only D2 dopamine receptors (80.9 +/- 9.8 fmol/mg protein) which were negatively coupled to adenylate cyclase activity. These findings suggest that the immortalized monoclonal hybrid cell lines are of neuronal origin and have incorporated elements of the medium spiny and cholinergic neurons of the developing striatum.

Do immunosuppressants cause posttransplant diabetes mellitus?

BACKGROUND

Posttransplant diabetes mellitus (PTDM) was originally described by Starzl in 1964. The incidence is around 3-46%, according to several reports. Etiologies and risk factors of PTDM have been discussed after it was described and recognized as a complication of renal transplantation.

METHODS

Twenty-five consecutive renal transplants in 24 recipients were reviewed, and 3 cases of posttransplant diabetes mellitus were found. Cyclosporine A (CsA), Azathioprine (Aza) dose and maintenance dose of Prednisolone (Pred.), rejection episodes, total dosage of steroid used at the time of acute rejection were carefully recorded and analyzed.

RESULTS

The mean age of 3 living-related and 22 cadaveric transplant recipients was 32.7 +/- 7.5 and 33.5 +/- 6.8 years in PTDM and non-PTDM patients, and the onset of PTDM was, on the average, 11.3 +/- 10.6 months. Comparative studies between non-PTDM and PTDM groups showed that age, rejection episodes, total dose of methylprednisolone used in acute rejection, CsA level, and dosage of CsA, Aza and prednisolone at 1,6,12 and 24 months were not significantly different from one another.

CONCLUSIONS

No significant risk factors or definitive mechanism involved in the development of PTDM were identified in this study. It is suggested that immunosuppressants are involved in the occurrence of PTDM, and probably neither a single factor is responsible nor is dose dependency involved.

[Intestinal endotoxin translocation in endotoxemic rats]

It has been known that enterogenic endotoxemia is an important pathogenetic factor in multiple organ failure. However, pathogenetic mechanism of enterogenic endotoxemia is yet unclear. In this work, experiments were performed on intact animal or isolated rat ilea-vascular perfusion apparatus and membrane vesicles produced from the extraction of brush border of rat intestinal mucosa. It is found that circulating endotoxin prompted intestinal endotoxin translocation in a positive feedback manner. Various regulatory peptides modulated the endotoxin translocation: endothelin stimulated and atrial natriuretic peptide inhibited the endotoxin translocation, and the pathway of enterogenic endotoxin translocation is mainly not transcellular, probably paracellular. It is also found that taurine significantly inhibited intestinal endotoxin translocation and protected the animals from endotoxemic injury.

Thermal inactivation of shrimp deoxyribonuclease with and without sodium dodecyl sulfate

Due to the differences in sample treatment, purified shrimp DNase migrates to different positions in sodium dodecyl sulfate (NaDod-SO4) polyacrylamide gel electrophoresis. DNase molecules migrating to some of these positions are enzymatically active as revealed by the DNase activity stain in situ. When the sample is not heated, DNase molecules (Form I) migrate to a position corresponding to an apparent Mr of 22 000 and are stain DNase-active. When the sample is heated with NaDod-SO4, DNase molecules (Form II) migrate to the apparent Mr of 39 000 position and are also DNase-active. In contrast, when the sample is heated without NaDod-SO4, DNase molecules (Form II') migrate to the same position as Form II but are DNase-inactive. When the sample is heated in the presence of beta-mercaptoethanol (with or without NaDod-SO4), the inactive Form III is generated. Form III must be the fully extended polypeptide because its apparent Mr is very close to the true Mr of DNase. These treated samples were also analyzed for DNase activity by diluting DNase-NaDod-SO4 into the DNase (hyperchromicity) assay solution. The results are consistent in that only Forms I and II are DNase-active. However, Form I differs from Form II in the time required for expression of DNase activity. After dilution of NaDod-SO4. Form II requires approx. 60 min to attain full activity while Form I is active immediately. Form II itself is inactive. The activity found at the Mr 39 000 position is due to conversion of Form II to the active Form I, as revealed by two-dimensional NaDod-SO4 gel electrophoresis. The sample heated without NaDod-SO4 soon contains active Form II, indicating that Form II is an intermediate during the production of Form II'. When Form II' is heated with NaDod-SO4, it does not refold back to the native state through Form II, suggesting that Form II' is irreversibly denatured. Thus, the anomalous behaviors of shrimp DNase in NaDod-SO4 gel electrophoresis have been utilized to study, in the presence and absence of NaDod-SO4, the thermal unfolding, as well as the refolding to the active enzyme during cooling and NaDod-SO4 removal.

Molecular evidence for the hybrid origin of Paulownia Taiwaniana based on RAPD markers and RFLP of chloroplast DNA

Genomic DNA of Paulownia fortunei, P. kawakamii and P. taiwaniana were amplified with 10-base primers of arbitrary sequences using the polymerase chain reaction (PCR). A total of 351 DNA fragments were amplified from 23 primers and of these 265 fragments (75.5%) were polymorphic. Almost all of the PCR-amplified products of P. taiwaniana were shared by either P. fortunei or P. kawakamii, or both, and the number of polymorphic fragments shared by P. taiwaniana and P. fortunei was about equivalent to those shared by P. taiwaniana and P. kawakamii. Restriction fragments of chloroplast DNA (cpDNA) purified from Paulownia species and from reciprocal crosses between P. fortunei and P. kawakamii were analyzed. Restriction enzyme SalI-digested cpDNA showed an identical pattern in both P. kawakamii and P. taiwaniana. These results further support the hypothesis that P. taiwaniana is the natural hybrid between P. fortunei and P. kawakamii and that the maternal parent of P. taiwaniana is P. kawakamii.

The relationship between PGE2 level in mothers' milk and physiological diarrhea of the baby and the treatment

Physiological diarrhea of baby during the period of breastfeeding often occurs. To investigate the relationship between mother's milk and the physiological diarrhea of baby, we measured the PGE2 levels in milk of 320 lactating women within 4 months of postpartum with radioimmunoassay and the mean value of PGE2 level was 216.8 +/- 145.2 ng/L. The PGE2 levels in mother's milk in the group with diarrhea were 286.5 +/- 142.2 ng/L, that of control group 130.4 +/- 76.3 ng/L. The difference was obviously significant (P < 0.001). The physiological diarrhea of baby was positively related to the PGE2 level in mother's milk (r = 0.75, P < 0.01) i.e., the high PGE2 level in mother's milk may be an important cause of diseases. The observation on 102 cases of baby with severe physiological diarrhea showed a higher level of PGE2 in the mother's milk. 52 cases of lactating women in the treated group were given indomethacin, and after treatment the PGE2 level in mother's milk decreased obviously, and the diarrhea of baby disappeared. The effective rate was 96.15%. No side effects were found in both mother and baby.

Characterization of OhS1, an arginine/lysine amidase from the venom of king cobra (Ophiophagus hannah)

In this paper, we present the results of purification and characterization of an arginine/lysine amidase from the venom of Ophiophagus hannah (OhS1). It was purified by Sephadex G-75 gel filtration and ion-exchange chromatography on DEAE-Sepharose CL-6B. It is a protein of about 43,000, consisting of a single polypeptide chain. It is a minor component in the venom. The purified enzyme was capable of hydrolysing several tripeptidyl-p-nitroanilide substrates having either arginine or lysine as the C-terminal residue. We studied the kinetic parameters of OhS1 on six these chromogenic substrates. OhS1 did not clot fibrinogen. Electrophoresis of fibrinogen degraded with OhS1 revealed the disappearance of the alpha- and beta-chains and the appearance of lower mol. wt fragments. OhS1 had no hemorrhagic activity. It did not hydrolyse casein, nor did it act on blood coagulation factor X, prothrombin and plasminogen. The activity of OhS1 was completely inhibited by NPGB, PMSF, DFP, benzamidine and soybean trypsin inhibitor, suggesting it is a serine protease. Metal chelator (EDTA) had no effect on it.

[Effects of extracts from Phyllanthus urinaria L. on HBsAg production in PLC/PRF/5 cell line]

Experiment on the effect of extracts from Phyllanthus urinaria on HBsAg production in PLC/PRF/5 human hepatoma cell line showed that the production was decreased markedly 48 hours after the treatment of cells with 2-4 mg/ml Phyllanthus urinaria, especially in combination with 10(-5) mol/L of Ara-A. The decrease of extracellular HB-sAg excretion seems to stem from the inhibition of intracellular HBsAg formation.

[Preliminary study on RFLPs for dystrophin gene in Chinese]

We have studied the RFLPs distribution and frequency of dystrophin gene in Chinese by using 14 subclones of complete 14 kb cDNA for the dystrophin gene as hybridization probes. Allelic fragments are detected in hybridization patterns of Pvu II/1a, Taq I/2b-3, Taq I/5b-7, Xba I/10. Among them, the allelic fragments (26 kb and 3.8 kb) in Pvu II/2b-3 patterns and the allelic fragments (10 kb and 8.4 kb) in Taq I/5b-7 patterns are the new RFLPs which have never been reported. From the comparison of our data with those of Caucasian and Japanese respectively and their statistical analysis, we can obtain the results as follows: There is remarkable difference (p less than 0.01) of the allelic fragment frequency in Taq I/2 b-3 (A1 = 3.4 kb, fre. 0.04; A2 = 3.2 kb, fre. 0.96) and Xba I/10 (A1 = 7.4 kb, fre. 0.41; A2 = 6.7 kb, fre. 0.59) between Chinese and Caucasian. The frequency of the allelic fragments A2 in Taq I/8 (A1 = 6.5 kb, A2 = 5.6 kb) and EcoR V/9 (A1 = 11.8 kb, A2 = 10.7 kb) are high in Caucasian, but have not been detected in Chinese. These differences are also highly significant. But the B1B2 allelic frequencies in Taq I/5 b-7 (B1 = 3.2 kb, B2 = 1.6 kb) are the same. There is no significant difference in the frequency of the allelic fragments A1A2 and B1B2 in Pvu II/1 a between Chinese and Japanese. Preliminary results suggest that there probably are high frequencies for spontaneous neutral mutations in the evolution process of the huge dystrophin gene (about 2,300 kb). In the meantime, the neutral mutation frequencies of various sectional sequences have remarkable differences, and that of some sectional sequences of the gene between Chinese and Caucasian may also have remarkable differences.

[Kinetic observation on BRC immune function of patients with epidemic hemorrhagic fever]

The RBC immune function of 88 patients with epidemic haemorrhagic fever (EHF) was examined kinetically with complement-labeled yeast method established by Guo Feng. The results showed that the percentage of RBC c3b receptor rossette, activity of RCIA-enhancing factor and c3 in sera of patients during the 3 different phases of EHF were markedly lower than those of the normal controls, while the percentage of RBC IC rossete, activity of RCIA-inhibiting factor and CIC in sera of the patients were manifestly higher (P less than 0.01). The change of all the indices observed above was most apparent in oliguric phase. This suggested that RBC immune function is lowered in the process of EHF.

Effect of a taurine-supplemented diet on conjugated bile acids in biliary surgical patients

The effect of a taurine-supplemented diet on the level of conjugated bile acids in postoperative patients was investigated during two consecutive 5-day period. Eighteen hepatobiliary patients with choledochostomies and a specific T-tube insertion were collected and divided randomly into two groups. In group 1, an ordinary postoperative soft diet was prescribed for the first 5 postoperative days and then followed with a taurine-supplemented soft diet (40 mumol/kg per day) for 5 consecutive days. In group 2, the taurine-supplemented diet was prescribed in reverse. At the end of the two periods, on days 5 and 10, bile was collected via a T-tube with an inflatable balloon and low-pressure motor suction. Analysis of conjugated bile acids was done by high-performance liquid chromatography. The results showed that a taurine-supplemented diet increased the concentration of taurocholic acid, glycocholic acid, taurochenodeoxycholic acid, glycochenodeoxycholic acid, and total bile acid from 0.5, 1.9, 0.3, 1.4, and 4.7 mg/mL (on day 5) to 1.1, 3.5, 1.0, 2.6, and 8.9 mg/mL, respectively, on day 10 in group 1. Similar findings were noted in group 2. These results indicate that a taurine-supplemented diet may enhance the conjugation and secretion of bile acid in hepatobiliary patients.

Synthesis and biological activity of 2-amino-1-oxa-2,3-dihydro-1-H-phenalene derivatives

The preparation of two 2-dialkylamino-1-oxa-2,3-dihydro-1H-phenalenes (3 and 4) is described. Lewis acid-catalyzed Baeyer-Villiger reaction of acenaphthenone (5) gave the lactone 6. Reduction afforded the lactol 7, which was reacted with amines to give the target compounds 3 and 4. Investigation of the effects of these compounds on catechol and indole metabolism revealed that they lack the dopamine antagonist or agonist and serotonin agonist properties of the respective deoxy analogues.

Purification and Characterization of Glutamyl-tRNA Synthetase : An Enzyme Involved in Chlorophyll Biosynthesis

Chlorophyll biosynthesis starts with the synthesis of glutamyl-tRNA (glu-tRNA) by a glutamyl-tRNA synthetase (Glu RS). The glu-tRNA is subsequently transformed to delta-aminolevulinic acid (ALA), which is a committed and regulated precursor in the chlorophyll biosynthetic pathway. The Glu RS from a green alga, Chlamydomonas reinhardtii, was purified and shown to be able to synthesize glu-tRNA and to participate in ALA synthesis in a coupled enzyme assay. Physical and chemical characterization of the purified Glu RS indicated that the enzyme had been purified to homogeneity. The purified enzyme has a native molecular weight of 60,000, an isoelectric point of 4.6, and it formed a single band of 32,500 daltons when analyzed by a silver stained denaturing gel. The N-terminal amino acid sequence of the 32,500 dalton protein was determined to be Asn-Lys-Val-Ala-Leu-Leu-Gly-Ala-Ala-Gly. The molecular weight analyses together with the unambiguous N-terminal amino acid sequence obtained from the purified enzyme suggested that the native enzyme was composed of two identical subunits. Polyclonal antibodies raised against the purified and denatured enzyme were able to inhibit the activity of the native enzyme and to interact specifically with the 32,500 dalton band on Western blots. Thus, the antibodies provided an additional linkage for the structural and functional identities of the enzyme. In vitro experiments showed that over 90% of the glu RS activity was inhibited by 5 micromolar heme, which suggested that Glu RS may be a regulated enzyme in the chlorophyll biosynthetic pathway.

Nucleotide sequence of the celA gene encoding a cellodextrinase of Ruminococcus flavefaciens FD-1

The nucleotide sequence of a 3.6 kb DNA fragment containing a cellodextrinase gene (celA) from Ruminococcus flavefaciens FD-1 was determined. The gene was expressed from its own regulatory region in Escherichia coli and a putative consensus promoter sequence was identified upstream of a ribosome binding site and a TTG start codon. The complete amino acid sequence of the CelA enzyme (352 residues) was deduced and showed no significant homology to cellulases from other organisms. Two lysozyme-type active sites were found in the amino-terminal third of the enzyme. In E. coli the cloned Cel A protein was translocated into the periplasm. The lack of a typical signal sequence, and the results of transposon phoA mutagenesis experiments indicated that CelA is secreted by a mechanism other than a leader peptide.

Biological significance of enhanced mitochondrial ketogenesis during the early stages after 70% hepatectomy in rats

Ketogenic capacity of mitochondria from the remnant liver of 70% hepatectomized rats was studied in relation to mitochondrial phosphorylative activity. Ketogenic capacity increased to a maximum of 6.04 +/- 0.39 from 3.84 +/- 0.13 of control, with an enhancement of mitochondrial phosphorylative activity 6 hr after hepatectomy, and then decreased to normal levels within 24 hr. Adenylate energy charge, (ATP + 1/2ADP)/(ATP + ADP + AMP), of the remnant liver decreased to 0.825 +/- 0.006 as compared to 0.849 +/- 0.002 of control 6 hr after operation. At 12 hr, total ketone body concentrations of the arterial blood increased concomitant with a fall in ketone body ratio (acetoacetate/3-hydroxybutyrate) which reflects the decreased liver mitochondrial redox (NAD+/NADH) state. These findings suggest that an enhancement of mitochondrial fatty acid oxidation and ketogenesis occurs concomitant with an enhancement of mitochondrial phosphorylative activity in the remnant liver in response to a decreased energy charge after 70% hepatectomy.

Purification and Characterization of Pectinmethylesterase from Ficus awkeotsang Makino Achenes

Pectinmethylesterase from the pericarp of jelly fig (Ficus awkeotsang) achenes was extracted and purified to a specific activity of 289 micromole proton produced per minute per milligram protein. Pectinmethylesterase, a major protein with high specific activity in the crude extract, was monomeric with a molecular weight of 38,000. The enzyme preparation was stable in distilled water at 4 degrees C for at least 6 months, and at 60 degrees C for at least 10 minutes. This enzyme functioned optimally at pH 6.5 to 7.5 when the assay mixture contained no NaCl or at low NaCl concentration. The pH optimum shifted to lower pH as the NaCl concentration was increased. The K(m) value for pectin was 0.75 milligram per milliliter pectin, corresponding to a V(max) value of 310 micromoles per minute per milligram protein. Inhibition studies with antibodies indicated that jelly fig achene pectinmethylesterase and the two other pectinmethylesterases from orange and tomato were similar in their active site conformation; however, the surface determinants may be very different because no precipitation between anti-jelly fig pectinmethylesterase immune serum and the pectin methylesterase from orange and tomato could be observed in the double immunodiffusion analysis. Specific antisera raised against jelly fig achene pectinmethylesterase in a Western blot experiment also showed low similarity between jelly fig pectinmethylesterase with that from orange and tomato. This observation was also supported by the very low isoelectric point (pH 3.5) of jelly fig pectinmethylesterase, compared with high isoelectric points reported for most of the pectinmethylesterases. Amino acid composition and N-terminal sequence have been obtained. High homology of the N-terminal amino acid residues between jelly fig and tomato pectinmethylesterase (O Markovic, H Jornvall [1986] Eur J Biochem 158: 455-462) was observed. Pectinmethylesterase activity causes the release of protons from the deesterification of pectin such that a low pH environment is created, and this may be related to the cell growth. Pectinmethylesterase is not needed for jelly fig seed germination, however the gel formed from pectin and pectinmethylesterase may insure a water source for the germinating jelly fig seeds.

Modulation of Kupffer cell membrane phospholipid function by n-3 polyunsaturated fatty acids

Dietary n-3 polyunsaturated fatty acids (PUFAs) have been reported to improve clinical outcome in a number of inflammatory diseases including burns and sepsis. One mechanism contributing to the anti-inflammatory effect is the incorporation of n-3 PUFAs into membrane phospholipids which decreases macrophage eicosanoid production. We hypothesize that an additional mechanism for their effects is an alteration of membrane signal transduction that decreases macrophage responsiveness to inflammatory stimuli. Kupffer cells, the fixed macrophages of the liver, were obtained from rats pair fed diets for 6 weeks with 15% of calories supplied as menhaden (high n-3), corn (control), or safflower (high n-6) oils. The effects of the dietary oils on Kupffer cell membrane signal transduction and eicosanoid production were assessed by measuring inositol phospholipid (PI) metabolism, intracellular calcium responses, and prostaglandin E2 (PGE2) production to the inflammatory signals endotoxin (LPS) and platelet activating factor (PAF). The menhaden oil diet resulted in significant incorporation of n-3 PUFAs into total cellular PUFAs compared to corn and safflower oil. (total n-3 PUFAs, 28.1% menhaden vs 2.1% corn vs 1.2% safflower, P less than 0.03). This incorporation altered signal transduction of PAF as both PI turnover (65% +/- 10% of corn oil) and calcium response (0.6-fold vs 5.0-fold for corn oil) were significantly reduced in the menhaden oil group. (P less than 0.05) The menhaden oil diet also reduced significantly PGE2 production in response to PAF and LPS (corn, 348 +/- 23 pg/ml; menhaden, 48 +/- 6 pg/ml, P less than 0.01). We conclude that, in addition to modulating eicosanoid production, n-3 PUFAs can also alter macrophage membrane signal transduction.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum dehydroepiandrosterone sulphate and pubertal development in Chinese girls

Serum dehydroepiandrosterone sulphate (DHEAS), estradiol (E2), luteinizing hormone (LH) and follicle stimulating hormone (FSH) were measured by radioimmunoassay in 170 healthy school girls from 7-16 years old. Blood samples from postmenarcheal girls were taken on days 6-10 of the menstrual cycle. Bone age, height, weight, breast and pubic hair development were also investigated. Of the four hormones measured, serum DHEAS displayed the earliest elevation, at 7 years and upwards. A significant DHEAS increment at chronological age 13 years was observed. Girls with earlier menarche had higher DHEAS level than girls having later menarche. Serum DHEAS levels also correlated with bone age, height, weight, subcutaneous fat and pubertal stages. The results suggest that adrenal androgen might be involved in the initiation of puberty and female maturation.

Biosynthesis of delta-Aminolevulinic Acid in Chlamydomonas reinhardtii: Study of the Transamination Mechanism Using Specifically Labeled Glutamate

The first committed intermediate of chlorophyll biosynthesis, delta-aminolevulinic acid (ALA), is synthesized from glutamate in the plant cell. The last step of ALA synthesis is a transamination reaction which converts glutamate-1-semialdehyde (GSA) to ALA. The mechanism of the transamination was examined by using glutamate, specifically labeled with either 1-(13)C or (15)N, as substrate for ALA synthesis. After incubating with crude enzymes extracted from Chlamydomonas reinhardtii, the distribution of labels in purified ALA molecules was examined by nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. We found that both isotopes were present in the same ALA molecule. We interpret the results to mean that intermolecular transamination occurs during the conversion of GSA to ALA.

Effects of partial ischemia and reflow on mitochondrial metabolism in rat liver

To clarify the effects of partial ischemia and reflow on the mitochondrial metabolism of the rat liver, the afferent vessels supplying the left lateral and left half of medial lobes were occluded and then reperfused after given time periods of ischemia (30, 60, 90 and 120 min, groups A, B, C and D, respectively). Samplings were taken at 0, 10 and 60 min after reperfusion. The energy charge levels of ischemic lobes decreased rapidly from 0.85 +/- 0.01 in the sham group to 0.38 +/- 0.11, 0.35 +/- 0.07 and 0.34 +/- 0.06 in groups B, C and D, respectively. The phosphorylative activities of mitochondria isolated from ischemic lobes decreased gradually along with the time of ischemia. The reversal of mitochondrial function and energy charge levels following reperfusion was noted in groups A and B. In nonischemic lobes, the phosphorylation rate (nmol ATP/mg/min) increased from 90 +/- 6 in sham group to 125 +/- 12 and 130 +/- 9; 131 +/- 5 and 130 +/- 6; 123 +/- 6 and 122 +/- 17, and 138 +/- 6 and 138 +/- 13 at 10 and 60 min after reflow in groups A, B, C and D, respectively (p less than 0.05). The energy charge level of nonischemic lobes decreased from 0.85 +/- 0.01 of sham group to 0.80 +/- 0.03 in group D (p less than 0.05). From these results, it is concluded that the transitional zone for the reversal of mitochondria function and energy metabolism following prolonged liver ischemia appears at around 60 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of an intermediate of delta-aminolevulinate biosynthesis in Chlamydomonas by high-performance liquid chromatography

The first committed intermediate of the chlorophyll biosynthetic pathway is delta-aminolevulinic acid (ALA). In plant cells, ALA is formed from glutamate by a pathway not yet clearly defined. One of the proposed pathways involves the reduction of glutamate to glutamate-1-semialdehyde (GSA) via a glutamyl-tRNA intermediate. GSA is then converted to ALA by an aminotransferase. We are studying this pathway using partially purified components from Chlamydomonas reinhardtii in in vitro reactions with [3H]L-glutamate as the substrate and analysis of the radioactive reaction products via HPLC. In reactions either lacking GSA-aminotransferase or containing gabaculine (an inhibitor of aminotransferase), a radioactive intermediate is formed which cochromatographs with synthetic GSA. As observed previously for ALA synthesis, the synthesis of this intermediate has an absolute requirement for RNA, ATP, and active enzymes, while the requirement for NADPH is less stringent. Both the accumulated intermediate and the synthetic GSA can be converted to ALA by the aminotransferase without any additional substrates or cofactors. These results support previous observations that GSA or a very similar compound is an intermediate of ALA synthesis.

Chlorophyll biosynthesis in Chlamydomonas starts with the formation of glutamyl-tRNA

An RNA moiety has been shown to be involved in the conversion of Glu to delta-aminolevulinic acid (ALA), the first committed intermediate of the chlorophyll pathway. We now have evidence suggesting that in Chlamydomonas, the first reaction for converting Glu to ALA is the aminoacylation of Glu to a Glu-specific tRNA. The Glu-tRNA thus formed could be the substrate for Glu-1-semialdehyde synthesis catalyzed by a postulated dehydrogenase. Glu-1-semialdehyde can be converted to ALA by an aminotransferase. Of the three reactions converting Glu to ALA, only the second reaction, catalyzed by a postulated dehydrogenase, is sensitive to inhibition by heme (a known inhibitor of ALA synthesis). We think the regulated enzyme of ALA synthesis is the postulated dehydrogenase. It is postulated that in the chloroplast of Chlamydomonas, the synthesis of ALA and the synthesis of proteins may share a common pool of glutamyl-tRNA.

delta-Aminolevulinic acid-synthesizing enzymes need an RNA moiety for activity

When Chlamydomonas enzymes that convert glutamate to delta-aminolevulinic acid are separated into three fractions, one of the fractions contains RNA, and the RNA moiety is needed for the enzyme activity.

Purification, Characterization, and Fractionation of the delta-Aminolevulinic Acid Synthesizing Enzymes from Light-Grown Chlamydomonas reinhardtii Cells

The synthesis of delta-aminolevulinate from glutamate by Chlamydomonas reinhardtii membrane-free cell homogenates requires Mg(2+), ATP, and NADPH as cofactors. The pH optimum is about 8.3. When analyzed by a Fractogel TSK gel filtration column the delta-aminolevulinate synthesizing enzymes, including glutamate-1-semialdehyde aminotransferase, elute with an apparent molecular weight of about 45,000. The enzymes obtained from the gel filtration column were separated into three fractions by affinity column chromatography. One fraction binds to heme-Sepharose, one to Blue Sepharose, while the enzyme converting the putative glutamate-1-semialdehyde to delta-aminolevulinic acid is retained by neither column. All three fractions are necessary for the conversion of glutamate to delta-aminolevulinate. The delta-aminolevulinate synthesizing enzymes from Chlamydomonas are sensitive to inhibition by heme but not sensitive to inhibition by protoporphyrin.

Metabolism of Magnesium Protoporphyrin Monomethyl Ester in Chlamydomonas reinhardtii

The y-1 mutant of Chlamydomonas reinhardtii is defective in the conversion of protochlorophyllide (Pchlide) to chlorophyllide in the dark. Aerobic delta-aminolevulinic acid (ALA) feeding of y-1 cells causes protoporphyrin monomethyl ester (PME) to accumulate in addition to increased levels of Pchlide. y-1 cell homogenates are not capable of methylating protoporphyrin (PROTO) to form PME but can methylate magnesium protoporphyrin (MgP) to form magnesium protoporphyrin monomethyl ester (MgPME). Anaerobic ALA feeding of y-1 causes concomitant accumulation of PME and MgPME. y-1 cells treated with alpha,alpha'-dipyridyl (DP) accumulate MgPME but not PROTO or PME. A mutant strain (bme) of Chlamydomonas has been isolated which has very little chlorophyll and accumulates PME. bme Cell homogenates can methylate MgP but not PROTO. We propose that: (a) in Chlamydomonas, PME is the initial breakdown product of MgPME; (b) both the breakdown of MgPME to PME and the conversion of MgPME to Pchlide require O(2); (c) the breakdown of MgPME to PME appears to require Fe; and (d) the PME accumulated in the bme mutant is the result of an increased breakdown of MgPME.

Molecular interactions of progesterone analogues with rabbit uterine cytoplasmic receptor

Binding energies of progesterone analogues with single modifications were calculated from their affinities for the cytosolic receptor of rabbit uteri. The effects of individual substituents were analyzed in terms of hydrogen bonds, van der Waals' forces, and hydrophobic interactions. Binding to the receptor is attributed to hydrogen bonds involving the ketones at carbons 3 and 20, and van der Waals' interactions at carbons 2, 4, 7, 9, 12, 18, and 19 at which positions the separation of the steroid from the receptor appears to be about 0.1 nm or less. Greater separation occurs at carbons 6, 11, 14, 15, 16, and 21. The receptor probably has a hydrogen acceptor approximating the 11 beta position of the bound steroid. The enthalpy of binding of the progesterone molecule is about 26 kcal/mol but on the basis that the two hydrogen bonds contribute about 6 kcal/mol and each of the van der Waals' attractions about 1 kcal/mol, the sum of the individual bonds totals only about 20 kcal/mol. The difference of 6 kcal/mol is attributed to intrareceptor bonds that are established after a change in receptor conformation is initiated by progesterone binding. This change in conformation fixes the steroid in its protein niche and retards dissociation. We speculate that this alteration in conformation is related to "activation" and possibly other functions of the complex.

Temperature dependence of kinetic interactions between progesterone and the uterine cytoplasmic receptor

The temperature dependence of the rates of dissociation and association for progesterone-receptor interactions was measured over the temperature range of 0-20 degrees C. The dissociation process is biphasic indicating that either two forms of receptor are present or that the binding of progesterone to the receptor is a concatenated reaction. The enthalpy of activation for the dissociation of progesterone from the receptor is about 26-28 kcal/mol and the entropic energy of activation is about -5 kcal/mol. The enthalpy of activation for the association of these molecules is about 3 kcal/mol and the entropic energy of activation is about 6 kcal/mol. These data are consistent with a model of progesterone binding to the receptor that includes hydrogen bonds between each of the two ketone groups and hydrogen donors on the receptor protein and involves van der Waals' interactions, due to the close proximity of the receptor binding site to a large fraction of the progesterone surface.

Photoactivation of Chlorophyll Synthesis and Cytochrome Oxidase Activity in Anaerobically Germinated Seedlings of Echinochloa crusgalli var. Oryzicola

When seeds of Echinochloa crusgalli var. oryzicola are germinated in dark anaerobic conditions (99.995% N(2)), the seedlings do not have detectable protochlorophyll(ide). Two hours after exposure to light aerobic conditions, they begin to synthesize chlorophyll. The lag in greening is shorter in seedlings exposed to light for 24 hours before exposure to air. Seedlings maintained in light anaerobic conditions exhibit no lag in greening upon transfer to an aerobic environment. Preillumination of anaerobically grown seedlings does not result in any chlorophyll accumulation. Phytochrome is probably the receptor for photoactivation of chlorophyll synthesis, since activation is achieved by red light alone, but not by far red light or red plus far red light. The cytochrome oxidase activity in anaerobically germinated seedlings is 30% of the normal level found in aerobically grown seedlings. Preillumination was also found to activate the ability of anaerobically germinated seedlings to increase their cytochrome oxidase activity upon exposure to air.

Photoconversion of Photochlorophyllide in the y-1 Mutant of Chlamydomonas reinhardtii

Dark-grown y-1 mutant cells of Chlamydomonas reinhardtii accumulate protochlorophyllide (Pchlide) in both 635 nanometers (P635) and 650 nanometers (P650) forms. Plastids in these cells lack the normal thylakoid membrane structure except some remnants of membrane vesicles. Using difference spectrophotometry, P635 is shown to be photoconverted to chlorophyllide at 672 nanometers (C672) and P650 is photoconverted to C688 followed by a rapid shift to C672 (Shibata shift) and regeneration of P650. Some of the Pchlide is not photoconverted despite repeated illumination. Although P650 is destroyed by freezing and thawing, it is not transformed into P635. Freezing and thawing treatment also made Pchlide no longer photoactive.

Effect of Dim Light on the y-1 Mutant of Chlamydomonas reinhardtii

The y-1 mutant of Chlamydomonas reinhardtii tends to die or revert to wild type when grown in the dark for a long period of time. A small amount of white light (0.5 lux) enables the y-1 mutant to grow indefinitely in a "near dark" condition. Under this condition, the y-1 mutant is physiologically and ultrastructurally similar to the dark-grown y-1 yet remains genetically stable.

Bragg effect waveguide coupler analysis

We present an approach to the analysis of a holographically produced grating coupler, in which we separate the coupling problem into independent slab waveguide and diffraction grating problems. Considering the guiding structure as a slab waveguide, we obtain the parameters of the propagating modes of the coupler through conventional analysis. The diffraction efficiency of the grating orders are then calculated by using the thin grating decomposition method (TGD). Utilizing the propagating mode angles of the waveguide and the calculated diffraction efficiencies of the grating, we are able to calculate the radiation loss coefficient and therefore the coupling efficiency of the holographic waveguide coupler.

Genetic control of chlorophyll biosynthesis in Chlamydomonas. Analysis of mutants at two loci mediating the conversion of protoporphyrin-IX to magnesium protoporphyrin

In this report we describe two nonallelic Mendelian protoporphyrin accumulating mutants br(s)-1 and br(c)-1. Results of experiments with these mutants lead us to postulate that porphyrin biosynthesis branches into light and dark steps between protoporphyrin-IX and magnesium protoporphyrin. We hypothesize that the br(c) locus controls a dark step while the br(s) locus either controls a step in the main pathway before the branch or mediates the preparation of the magnesium ion for its insertion into protoporphyrin-IX. The br(s)-1 mutant is thought to be light sensitive because a block prior to the branch point in the porphyrin pathway prevents chlorophyll formation in either the light or the dark. The br(c)-1 mutant, which also accumulates protoporphyrin in the dark, forms chlorophyll and chloroplast lamellae when transferred to the light, showing that function of the porphyrin pathway is normal in the light.