[Separation of soybean agglutinin by hydrophobic-interaction chromatography]

The soybean agglutinin (SBA) was separated with hydrophobic-interaction chromatography (HIC) in this work. HIC of the crude lectin extract of SBA was performed on Phenyl-Sepharose CL-4B column, 10 cm x 2.5 cm i.d., at a flow-rate of 1.0 mL/min. A 20 mL sample of the crude extract was applied to the column previously equilibrated with the buffer, 0.01 mol/L PBS containing ammonium sulfate (60% of saturation concentration). The column was eluted with the starting buffer, then with the buffer containing 30% saturation of ammonium sulfate, and finally with 0.01 mol/L PBS. Fractions were detected by UV absorbance at 280 nm and assayed for hemagglutinating activity. The results show that the purification-fold was as high as 35 and the recovery of activity was 100%.

Genetic and immunological adaptation of Heligmosomoides polygyrus in mice

Two lines of Heligmosomoides polygyrus, QN and QA, were selected by passage, respectively, through naive and immune Quackenbush (Q) mice and their biology and capacity to induce immune responses in homologous Q and heterologous low- (SL) and high-responder (RH) mice were assessed. QA H. polygyrus survived the impact of otherwise protective immunity in Q mice better than did QN parasites, especially after a secondary infection. The enhanced survival of QA parasites was observed also in SL but not in RH mice. Infections with QA phenotypes induced a reduced antibody response and lower eosinophilia compared to QN parasites in Q mice. The total numbers of nucleated cells in the mesenteric lymph node (MLN) and spleen increased to different extents according to the genotype of the mice and the phenotype of parasite used: the increase was most profound in RH, least in SL and intermediate in Q mice; QN induced more lymphocytosis in the MLN and spleen than did QA parasite phenotypes. B cells from MLN and spleen, stained with fluorochrome-conjugated antibody against mouse Ig, showed increased intensity of fluorescence in the flow cytometric assay after infection with H. polygyrus, but to different degrees: the intensity increased most in RH and least in SL mice; more in Q mice infected with QN than with QA H. polygyrus. These results suggest that adaptation of parasites to immunity of the host is associated with reduction of their immunogenicity and is specific to the immune status and genotype of the host to which the parasites have become adapted.

Methionine aminopeptidase (type 2) is the common target for angiogenesis inhibitors AGM-1470 and ovalicin

BACKGROUND

Angiogenesis, the formation of new blood vessels, is essential for tumor growth. The inhibition of angiogenesis is therefore emerging as a promising therapy for cancer. Two natural products, fumagillin and ovalicin, were discovered to be potent inhibitors of angiogenesis due to their inhibition of endothelial cell proliferation. An analog of fumagillin, AGM-1470, is currently undergoing clinical trials for the treatment of a variety of cancers. The underlying molecular mechanism of the inhibition of angiogenesis by these natural drugs has remained unknown.

RESULTS

Both AGM-1470 and ovalicin bind to a common bifunctional protein, identified by mass spectrometry as the type 2 methionine aminopeptidase (MetAP2). This protein also acts as an inhibitor of eukaryotic initiation factor 2alpha (elF-2alpha) phosphorylation. Both drugs potently inhibit the methionine aminopeptidase activity of MetAP2 without affecting its ability to block elF-2alpha phosphorylation. There are two types of methionine aminopeptidase found in eukaryotes, but only the type 2 enzyme is inhibited by the drugs. A series of analogs of fumagillin and ovalicin were synthesized and their potency for inhibition of endothelial cell proliferation and inhibition of methionine aminopeptidase activity was determined. A significant correlation was found between the two activities.

CONCLUSIONS

The protein MetAP2 is a common molecular target for both AGM-1470 and ovalicin. This finding suggests that MetAP2 may play a critical role in the proliferation of endothelial cells and may serve as a promising target for the development of new anti-angiogenic drugs.

H-2 genes and resistance to infection with Heligmosomoides polygyrus in selectively bred mice

Two lines of mice bred selectively for high resistance (RH) and susceptibility (SL) to reinfection with Heligmosomoides polygyrus demonstrated disparate levels of resistance to infection but did not differ in the frequency of H-2 antigens when assayed with antisera against antigens of 5 inbred H-2 haplotypes. The selected RH and SL mice were crossbred with, and backcrossed to, the inbred CBA mice. F1 mice from crosses between RH and CBA were as resistant to reinfection with H. polygyrus as their RH parents. F1 mice from crosses between SL and CBA were more resistant than either of their parents. BC1 mice were either positive or negative for H-2 antigens from RH and SL mice. BC1 mice that were positive for RH H-2 antigens were more resistant to infection than their negative littermates, but they were significantly more susceptible to infection with H. polygyrus than their F1 parents. These results demonstrated that genes within and mapped outside H-2 complex control the level of resistance to H. polygyrus in the selected mice and suggested that selective breeding of mice for resistance fixed the relevant genes in and outside the H-2 complex.

[Liver-protective activity of Aralia taibaiensis Z.Z. Wang et H.C. Zheng]

Compared with oleanolic acid and sodium chloride physiological solution, the water decoction of and the total saponin in root and cortex of Aralia taibaiensis were testified to have significant protective activity in experimental acute liver injury in mice induced by CCl4.

[Resources survey of medicinal species from genus Aralia]

This paper deals with the distribution area, growing environment and medicinal parts of 19 species and 1 variety, including 2 new species of genus Aralia. An index for identification of these medicinal species is presented.

High density lipoproteins increase cytoplasmic free calcium in bovine aortic endothelial cells

This study examined the influence of human high density lipoproteins (HDL) on the intracellular free calcium of cultured bovine aortic endothelial cells (BAECs). Intracellular Ca2+ concentration ([Ca2+]i) was determined by a fluorescent calcium indicator, Fura-2. It was found that, in the presence of 1 mmol/L extracellular calcium, HDL resulted in a biphasic elevation of [Ca2+]i in BAECs, consisting of an initial, transient component followed by a lower, but more sustained component. Doses of HDL from 25 to 200 micrograms protein/ml induced marked concentration-dependent elevations of [Ca2+]i in BAECs. The sustained component was abolished by deprivation of extracellular calcium or by pretreatment of endothelial cells with a calcium influx blocker, NiCl2, HDL-induced elevation of [Ca2+]i was attenuated in a concentration-dependent way by an inhibitor of calcium release, tetracaine. Repeated applications of HDL (100 micrograms protein/ml) markedly blunted the initial peak component of the calcium transient of BAECs. These results demonstrate that both intracellular and extracellular calcium pools are responsible for the biphasic elevation of [Ca2+]i induced by HDL in cultured BAECs.

[Interspecific difference and intraspecific variation of coumarins in Cnidium species]

According to the results of TLC and assay of coumarins, the interspecific difference of coumarins in 4 Cnidium species is obvious, and 4 chemotypes have been found in Cnidium monnieri.

Peroxynitrite formation from activated human leukocytes

We showed direct evidence of peroxynitrite formation from polymorphonuclear cells (PMN) with the nitration of 4-hydroxyphenylacetic acid (HPA) to 4-hydroxy-3-nitrophenylacetic acid (NO2HPA). Human PMN from healthy volunteers was stimulated with phorbol-12-myristate-13-acetate (PMA, 10 ng/ml) at 37 degrees C in 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid-buffered Hank's balanced salt solution (pH 7.4) with HPA (1 mM). NO2HPA was detected under PMA stimulation only in the presence of myeloperoxidase inhibitor. NO2HPA was eliminated by N-monomethyl-L-arginine (100 microM). The inhibition of myeloperoxidase appears to be essential to demonstrate the production of NO2HPA since myeloperoxidase itself or its product, hypochlorite, reacted with peroxynitrite and hampered the formation of NO2HPA.

Biosynthesis of the unusual amino acid (4R)-4-[(E)-2-butenyl]-4-methyl-L-threonine of cyclosporin A: enzymatic analysis of the reaction sequence including identification of the methylation precursor in a polyketide pathway

3(R)-Hydroxy-4(R)-methyl-6(E)-octenoic acid, the C9-backbone of the unusual amino acid (4R)-4-[(E)-2-butenyl]-4-methyl-L-threonine (Bmt), is biosynthesized as a coenzyme A thioester from acetyl-CoA, malonyl-CoA, NADPH, and S-adenosylmethionine via a polyketide pathway. Here we present detailed enzymatic studies about the basic assembly process. After attachment of the activated building units to Bmt polyketide synthase the intermediates remained enzyme-bound throughout the cycle. Premature cutoff of biosynthesis led to the release of the intermediates from the enzyme, either as coenzyme A thioesters or, in the case of reactive C8-intermediates, as lactones. Enzyme-bound 3-oxo-4-hexenoic acid, the condensation product of the second elongation cycle, could be identified as the exclusive substrate for the introduction of the methyl group. Part of the biosynthesis including the first elongation cycle, the second condensation reaction, and the methylation step was shown to follow a processive mechanism. All activated intermediates of this processive part could be introduced into the correct pathway at the respective steps, whereas 2-methyl-3-oxo-4-hexenoyl-CoA and all following methylated intermediates were not able to enter the cycle any more. Obviously, the region of Bmt polyketide synthase responsible for this latter part of the biosynthetic pathway is inaccessible for externally supplied coenzyme A thioesters. Butyryl-CoA was recognized by Bmt polyketide synthase with an efficiency comparable to that of crotonyl-CoA and processed to 3-hydroxy-4-methyloctanoyl-CoA, the saturated analog of the natural basic assembly product, indicating a relaxed specificity of Bmt polyketide synthase with respect to the starter unit.

The fourth EF-hand of calmodulin and its helix-loop-helix components: impact on calcium binding and enzyme activation

CaM (4 cTnC) is a calmodulin--cardiac troponin C chimeric protein containing the first, second, and third calcium-binding EF-hands of calmodulin (CaM) and the fourth EF-hand of cardiac troponin C (cTnC) [George, S.E., Su, Z., Fan, D., & Means, A.R. (1993) J. Biol. Chem. 268, 25213-25220]. CaM (4 cTnC) showed 2-fold-enhanced carboxy-terminal Ca2+ affinity relative to CaM and also exhibited impaired activation of the CaM-regulated enzymes smooth muscle myosin light chain kinase (smMLCK), neuronal nitric oxide synthase (nNOS), and phosphodiesterase (PDE). To investigate the molecular basis for these effects, we constructed (1) additional chimeras, replacing most of CaM helix 7, Ca2+-binding loop 4, and helix 8 with the corresponding helices and loops of cTnC; and (2) point mutants in the fourth EF-hand of CaM. Replacement of CaM's fourth loop with the corresponding loop of cTnC enhanced Ca2+ affinity by over 3-fold through an increase in the Ca2+ on rate and also reduced cooperativity of Ca2+ binding. In contrast, substitution of CaM helix 7 or 8 modestly decreased Ca2+ affinity by increasing the Ca2+ off rate, without impairment of cooperativity. All three of the helix and loop chimeras fully activated PDE, with minor shifts in Kact. CaM (helix 7 cTnC) showed a significantly impaired ability to activate smMLCK and nNOS, whereas the other two chimeras retained about 80% of the maximal smMLCK and nNOS activation observed with CaM.

[A study of HIA-DR antigen expression in nasopharyngeal carcinoma and its relation with clinical pathology and prognosis]

In order to clarify the relationship between HLA-DR antigen expression of nasopharyngeal carcinoma (NPC) and the clinicopathology and prognosis of NPC, immunohistochemical studies on HLA-DR antigen expression in 77 NPC cases were performed. The results showed that the positive rate of HLA-DR was 44.2% in this series. Non-neoplastic epithelium did not express this antigen. A close association was found between expression of HLA-DR antigen and the clinical staging of NPC. The positive rate of HLA-DR gradually decreased with tumor progression, showing a remarkable difference among tumors in different clinical stages (P < 0.05). Analysis of patient survival demonstrated that the prognosis of NPC patients with HLA-DR expression was significantly better than those without (P < 0.01). The above results give support to the possibility of immunomodulation of tumors.

[Dynamic assay of oleanolic acid in Aralia taibaiensis Z. Z. Wang et H. C. Zheng]

The dynamic assay on oleanolic acid (OA) in Aralia taibaiensis shows that the plant has a higher OA level. The level in root cortex is 4.74%-10.81% and peak stages are mid-May to late June and late August to mid-September the level in stem barks is 3.59%-12.06% and peak period is between mid-May and late July, the level in leaves increases throughout the life time ranging from 2.41% to 6.66% and peak level is 6.66% around mid-September.

[Studies on Cnidium fruits by stereological method and computer image analysis]

The fruits, pollen grains, vascular bundles, stomata and endosperm cells of 4 Cnidium species were studied and determined by stereological method and computer image analysis technique. Statistical data were presented. In the volume of fruit and the area of vascular bundle, Cnidium dahuricum is the biggest, then C. salinum, C. japonicum and C. monnieri successively. In the volume of pollen grain,C. salinum is the biggest, followed by C. dahuricum, C. japonicum and C. monnieri in succession. In the volume of endosperm cell, C. dahuricum is also the biggest, and then C. japonicum, C. salinum and C. monnieri in order.

The calmodulin-nitric oxide synthase interaction. Critical role of the calmodulin latch domain in enzyme activation

The neuronal isoform of nitric oxide synthase (nNOS) requires calmodulin for nitric oxide producing activity. Calmodulin functions as a molecular switch, allowing electron transport from the carboxyl-terminal reductase domain of nitric oxide synthase to its heme-containing amino-terminal domain. Available evidence suggests that calmodulin binds to a site between the two domains of nNOS, but it is not known how calmodulin then executes its switch function. To study the calmodulin-nNOS interaction, we created a series of chimeras between calmodulin and cardiac troponin C (cTnC, a homologue of calmodulin that does not activate nNOS). Although a few chimeras showed good ability to activate nNOS, most failed to activate. A subset of the inactive chimeras retained the ability to bind to nNOS and therefore functioned as potent competitive inhibitors of nNOS activation by calmodulin (CaM). The observed inhibition was additive with the arginine antagonists NG-monomethyl-L-arginine and 7-nitroindazole, indicating a distinct and independent mechanism of nNOS inhibition. To localize the calmodulin residues that account for impaired activation in the inhibitory CaM-cTnC chimeras, we conducted a detailed mutagenesis study, replacing CaM subdomains and individual amino acid residues with the corresponding residues from cTnC. This revealed that mutations in CaM helices 2 and 6 (its latch domain) have a disproportionate negative effect on nNOS activation. Thus, our evidence suggests that the CaM latch domain plays a critical role in its molecular switch function.

Anti-CD3:anti-IL-2 receptor-bispecific mAb-mediated immunomodulation. Low systemic toxicity, differential effect on lymphoid tissue, and inhibition of cell-mediated hypersensitivity

An anti-CD3:anti-CD25 (CD3,25) bispecific mAb was developed with the objective of combining the advantages of the parent anti-CD3 and anti-CD25 mAbs. The in vivo effects of the CD3,25 were examined in comparison to the parent Abs. The CD3,25 was well tolerated in vivo, in contrast to the parent anti-CD3 mAb, which induced systemic toxicity in recipient animals. Anti-CD3 mAb induced cell death, lymphoblast formation, and T cell activation in peripheral lymphoid organs; these were observed to a lesser extent in CD3,25-treated animals. In the thymus, anti-CD3 caused a progressive depletion of the CD4+ CD8+ "double positive" thymocytes, which was not seen in CD3,25-treated animals. This finding suggests that monovalent CD3 binding is insufficient to induce thymocyte apoptosis. Animals treated with a combination of anti-CD3 and anti-CD25 mAbs demonstrated changes in the lymphoid organs that were similar to anti-CD3-treated mice. This finding demonstrates that the effect of the CD3,25 is different than the sum of the parent Abs and suggests that the bispecific nature of the CD3,25 results in a reagent with unique immunomodulatory properties. The functional efficacy of the CD3,25 was assessed in a murine model of delayed-type hypersensitivity. The CD3,25 was as effective as the anti-CD3 mAb in inhibiting the delayed-type hypersensitivity reaction and was more effective than the parent anti-CD25 mAb. These data demonstrate that appropriately designed bispecific mAbs can be used as effective immunosuppressive agents with low systemic toxicity.

Anti-CD3:anti-IL-2 receptor-bispecific mAb-mediated immunomodulation. Low systemic toxicity, differential effect on lymphoid tissue, and inhibition of cell-mediated hypersensitivity

An anti-CD3:anti-CD25 (CD3,25) bispecific mAb was developed with the objective of combining the advantages of the parent anti-CD3 and anti-CD25 mAbs. The in vivo effects of the CD3,25 were examined in comparison to the parent Abs. The CD3,25 was well tolerated in vivo, in contrast to the parent anti-CD3 mAb, which induced systemic toxicity in recipient animals. Anti-CD3 mAb induced cell death, lymphoblast formation, and T cell activation in peripheral lymphoid organs; these were observed to a lesser extent in CD3,25-treated animals. In the thymus, anti-CD3 caused a progressive depletion of the CD4+ CD8+ "double positive" thymocytes, which was not seen in CD3,25-treated animals. This finding suggests that monovalent CD3 binding is insufficient to induce thymocyte apoptosis. Animals treated with a combination of anti-CD3 and anti-CD25 mAbs demonstrated changes in the lymphoid organs that were similar to anti-CD3-treated mice. This finding demonstrates that the effect of the CD3,25 is different than the sum of the parent Abs and suggests that the bispecific nature of the CD3,25 results in a reagent with unique immunomodulatory properties. The functional efficacy of the CD3,25 was assessed in a murine model of delayed-type hypersensitivity. The CD3,25 was as effective as the anti-CD3 mAb in inhibiting the delayed-type hypersensitivity reaction and was more effective than the parent anti-CD25 mAb. These data demonstrate that appropriately designed bispecific mAbs can be used as effective immunosuppressive agents with low systemic toxicity.

[Textual study and resource investigation on traditional Chinese drugs duhuo, jiuyanduhuo and qianghuo]

By means of Bencaological study on traditional Chinese drugs Duhuo, Jiuyanduhuo and Qianghuo, it has been found out that the Duhuo recorded in earlier Bencao works should be Qianghuo, and Duhuo was first used medically in the South-North Dynasty period, whereas Jiuy-anduhuo's medical use started in the Ming Dynasty. Resources of the three drugs were investigated and their main species were found out.

[Antitumor effect in vitro and immuno-response in vivo of fructus Mume]

The antitumor action of extracts from Fructus Mume and the main triterpenoid component ursolic acid on HIMeg and HL-60 cells in vitro was tested. The immuno-response in rats was also studied. The result showed that Fructus Mume had inhibiting effect on proliferation of HIMeg and HL-60 cells.

Effects of lysophosphatidylcholine on bovine aortic endothelial cells in culture

To elucidate the vascular actions of lysophosphatidylcholine, we examined its effects on the concentration of cytosolic free calcium ([Ca2+]i), plasma membrane fluidity and release of lactate dehydrogenase in vascular endothelial cells cultured from bovine aortas. The [Ca2+]i of the endothelial cells was measured by a dual-wavelength fluorospectrophotometer using a fluorescent, calcium-specific indicator, Fura-2. Membrane fluidity was monitored by measuring changes in the steady-state fluorescence anisotropies, using 1,6-diphenyl-1,3,5-hexatriene as a fluorescence probe. In the presence of 1 mmol/L extracellular calcium, lysophosphatidylcholine caused a biphasic elevation of [Ca2+]i in Fura-2-loaded vascular endothelial cells, consisting of a large transient component followed by a relatively low, but more sustained component. At concentrations of lysophosphatidylcholine equal to or greater than 10 mumol/L, [Ca2+]i increased in a dose-dependent manner in the presence or absence of external calcium. In the absence of extracellular calcium, only an initial transient increment in the [Ca2+]i of endothelial cells was generated, the sustained component being eliminated. The sustained component was greatly depressed or almost abolished by the addition of the calcium influx blocker, NiCl2. Plasma membrane fluidity was greatly increased by incubation with lysophosphatidylcholine (30 and 50 mumol/L) concomitant with significant increases in the release of lactate dehydrogenase from the cells. At 50 mumol/L, lysophosphatidylcholine increased lactate dehydrogenase release and membrane fluidity in a time-related way.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanisms of brain injury with deep hypothermic circulatory arrest and protective effects of coenzyme Q10

Sixteen dogs, divided randomly into a control group and coenzyme Q10 group (10mg/kg, intraperitoneally before the operation), underwent deep hypothermic circulatory arrest with cardiopulmonary bypass, as is done clinically. At four time points cerebral cortex and cerebrospinal fluid specimens were collected to study free radical formation, energy metabolism, and ultrastructure. During cardiopulmonary bypass cerebral electron spin resonance spectra and malondialdehyde contents were progressively higher than before bypass, especially at the 60 minutes of circulatory arrest and 30 minutes of reperfusion (p1 < 0.01, p2 < 0.05). In the coenzyme Q10 group at the latter two time points, they had increased less than in the control group at same time points (p1 < 0.02, p2 < 0.005). Adenosine triphosphate content in the cortex during bypass decreased gradually from the prebypass level (p1 < 0.02, p2 = p3 < 0.001), while lactate in cerebrospinal fluid increased (p1 < 0.05, p2 = p3 < 0.001). In the coenzyme Q10 group, adenosine triphosphate at the latter two time points was greater than that in the control group (p1 = p2 < 0.05), while the lactate changes were not significantly different from control at each time point (all p > 0.05). Ultrastructure of the cortex was normal before bypass and almost normal during bypass, but it was obviously abnormal at 60 minutes of circulatory arrest and more seriously abnormal at 30 minutes of reperfusion. In the coenzyme Q10 group the abnormality was obviously reduced. The results suggest that oxygen-derived free radicals and abnormal energy metabolism might play critical roles in brain ischemia/reperfusion injury. Coenzyme Q10 could protect the brain by improving cerebral metabolism.

Role of domain 3 of calmodulin in activation of calmodulin-stimulated phosphodiesterase and smooth muscle myosin light chain kinase

CaM[3 TnC] is a calmodulin-cardiac troponin C chimeric protein containing the first, second, and fourth calcium-binding domains of calmodulin (CaM) and the third calcium-binding domain of cardiac troponin C (cTnC) (George, S. E., Su, Z., Fan, D., and Means, A. R. (1993) J. Biol. Chem. 268, 25213-25220). CaM[3 TnC] shows altered activation of phosphodiesterase (PDE) and is a potent competitive inhibitor of smooth muscle myosin light chain kinase (smMLCK) activation by CaM. To determine why CaM[3 TnC] exhibits altered target enzyme interactions, we constructed a series of domain 3 CaM mutants. We began with subdomain substitutions, replacing most of CaM's helix 5, Ca2+ binding loop 3, and helix 6 with the corresponding subdomains of cTnC. Only CaM[helix 6-TnC] exhibited significant impairment of smMLCK and PDE activation. We then individually substituted the residues in the region of CaM's helix 6 with the corresponding cTnC residue. This revealed that CaM residues Thr-110, Leu-112, and Lys-115 were critical for full smMLCK activation and could not be substituted by the corresponding cTnC residue (Gln, Thr, and Thr, respectively). In contrast, only the L112T substitution significantly affected PDE activation. The CaM-smMLCK peptide structure (Meador, W. E., Means, A. R., and Quiocho, F. A. (1992) Science 257, 1251-1255) suggests a relationship between the proposed helix 6 smMLCK-activating residues and those previously described in helix 2 (VanBerkum, M. F. A., and Means, A. R. (1991) J. Biol. Chem. 266, 21488-21495).

Regression of cardiac hypertrophy and myosin isoenzyme patterns by losartan and captopril in renovascular hypertensive rats

To test the effect of losartan and captopril on cardiac hypertrophy and myosin isoenzyme, two-kidney, one-clip (2K 1C) renovascular hypertensive rats (RHR) were used. Eight weeks after the onset of hypertension, losartan 5 mg.kg-1.d-1 and captopril 50 mg.kg-1.d-1 were administered p.o. to 2 groups of RHR, respectively for 8 wk. The results showed that captopril significantly decreased the cardiac mass (607 +/- 169 mg vs 1029 +/- 132 mg) and total protein content (120 +/- 38 mg vs 198 +/- 31 mg), concomitant with significant decrease of arterial blood pressure (BP) (15.4 +/- 5.2 kPa vs 28.5 +/- 4.9 kPa). Losartan also induced a significant decrease in cardiac mass (671 +/- 116 mg vs 1029 +/- 132 mg) and protein content (142 +/- 29 mg vs 198 +/- 31 mg), as well as significantly lowered the BP (15.2 +/- 2.1 kPa vs 28.5 +/- 4.9 kPa). It is important to be note that both drugs normalized the shift of myosin isoenzyme in RHR. These results indicated that both drugs, having potent antihypertensive effects, can effectively reverse the cardiac hypertrophy and abnormal distribution of myosin isoenzyme patterns.

Prostacyclin analog (cicaprost) protects against damage by hydrogen peroxide to rabbit cardiac sarcoplasmic reticulum

The membrane fluidity of the cardiac sarcoplasmic reticulum in rabbit was monitored by measuring changes in steady-state fluorescence anisotropy (rs) using diphenylhexatriene as a probe. The Ca(2+)-ATPase activity of the sarcoplasmic reticulum was measured by assaying the amount of inorganic phosphate released from ATP. Hydrogen peroxide caused damage to the sarcoplasmic reticulum, as reflected by decreases in membrane fluidity and Ca(2+)-ATPase activity. The damage caused by hydrogen peroxide was completely prevented by 20 micrograms/ml catalase. Cicaprost (240 nM) provided an effective protection against injury to the sarcoplasmic reticulum caused by exposure to hydrogen peroxide. The rs value was significantly decreased from 0.154 +/- 0.014 to 0.122 +/- 0.005 (p < 0.01). Ca(2+)-ATPase activity was increased from 3.1 +/- 1.31 to 18.87 +/- 2.11 microM phosphate/mg protein/hour (p < 0.01). The protection given by cicaprost was dose dependent. We conclude that cicaprost protects against damage produced by hydrogen peroxide in cardiac sarcoplasmic reticulum in the rabbit. The mechanism of the effect of cicaprost remains to be elucidated.

[Studies on the effect of deltamethrin bath treatment of hamsters infected with Leishmania donovani for interrupting kala-azar transmission]

Phlebotomus chinensis were fed respectively on two groups of Cricetulus barabensis infected with Leishmania donovani, of which one group had received deltamethrin bath and the other was not treated with insecticide bath. The results showed that all the sandflies in the former group died within 24 hours, while those in the latter group had a high survival rate. Among the 165 sandflies examined, 114 (69.1%) became infected. The promastigotes not only developed well in the midgut, but also invaded esophagus, pharynx and proboscis. In the control group, the mortality of sandflies in 24 hours was 5.1% (3/59). According to the data obtained in the present study, the authors consider that insecticide bath treatment of infected domestic dogs in endemic villages could be used for interrupting kala-azar transmission.

Biosynthesis of the unusual amino acid (4R)-4-[(E)-2-butenyl]-4-methyl-L-threonine of cyclosporin A. Identification of 3(R)-hydroxy-4(R)-methyl-6(E)-octenoic acid as a key intermediate by enzymatic in vitro synthesis and by in vivo labeling techniques

The biosynthesis of (4R)-4-[(E)-2-butenyl]-4-methyl-L-threonine (abbreviation: Bmt, systematic name: 2(S)-amino-3(R)-hydroxy-4(R)-methyl-6(E)-octenoic acid) is proposed to involve two principal phases: the formation of a polyketide backbone and a subsequent transformation process to the final product. Here we report on the identification of 3(R)-hydroxy-4(R)-methyl-6(E)-octenoic acid as the end product of the first phase. The primary indication of 3(R)-hydroxy-4(R)-methyl-6(E)-octenoic acid as the key intermediate in the proposed biosynthetic route came from in vivo labeling studies with [1-13C,18O2]acetate, demonstrating retention of 18O in the 3-hydroxy group. Final identification of this intermediate in in vitro polyketide assays with enriched enzyme fractions of Tolypocladium niveum was achieved after development of highly sensitive and specific detection methods and by use of synthetic reference substances. Two additional methylated in vitro products could be detected and characterized as 4(R)-methyl-(E,E)-2,6-octadienoic acid and 4(R)-methyl-6(E)-octenoic acid by liquid chromatography-mass spectrometry analysis and comparison with synthetic reference samples. Their relevance for Bmt biosynthesis is discussed. Bmt polyketide synthase shows optimal activity at substrate concentrations of 200 microM acetyl-CoA, 150 microM malonyl-CoA, and 200 microM S-adenosylmethionine, around pH 7 and at 35 degrees C. Interestingly the Bmt backbone is released from the enzyme as a coenzyme A thioester, suggesting that subsequent transformation to Bmt takes place upon this activated intermediate.

Calmodulin-cardiac troponin C chimeras. Effects of domain exchange on calcium binding and enzyme activation

Calmodulin (CaM) and the cardiac isoform of troponin C (cTnC) are close structural homologs, but cTnC cannot activate most CaM target enzymes. To investigate structure-function relationships, we constructed a series of CaM.cTnC chimeras and determined their ability to bind Ca2+ and activate CaM target enzymes. Previously, we exchanged domain 1 and found that the chimeras exhibited profoundly impaired activation of smooth muscle myosin light chain kinase (smMLCK) and had differential effects on other CaM target enzymes (George, S. E., VanBerkum, M. F. A., Ono, T., Cook, R., Hanley, R. M., Putkey, J. A., and Means, A. R. (1990) J. Biol. Chem. 265, 9228-9235). One of the domain 1 chimeras was a potent competitive inhibitor of smMLCK. We now extend our study of CaM.cTnC chimeras by exchanging all of the remaining functional domains of CaM and cTnC. We determined the ability of the chimeras to bind Ca2+ and activate phosphodiesterase (PDE) and smMLCK. Chimeras containing both domains 3 and 4 of cTnC exhibited high affinity Ca2+ binding that was indistinguishable from cTnC, whereas chimeras containing either domain 3 or 4 of cTnC demonstrated Ca2+ affinity that was intermediate between CaM and cTnC. All of the CaM.cTnC chimeras showed near-maximal PDE activation but required 5-775-fold higher concentrations than CaM to produce half-maximal PDE activation. In contrast, all of the chimeras showed impaired ability to activate smMLCK, and some were potent competitive inhibitors of smMLCK activation by CaM.

[Qualitative analysis of Chinese drug xiakucao (Prunella)]

A high performance gas chromatographic procedure has been developed for the quantitation of ursolic acid and oleanolic acid in different parts of Xiakucao collected in different periods. The study provides a scientific foundation for increased availability and rational collecting periods of Xiakucao.

Effects of hydrogen peroxide on membrane fluidity and Ca(2+)-transporting ATPase activity of rabbit myocardial sarcoplasmic reticulum

This study was to investigate the effects of hydrogen peroxide on membrane fluidity and Ca(2+)-ATPase activity of rabbit myocardial sarcoplasmic reticulum (SR). The membrane fluidity of SR was monitored by measuring the changes in the steady state fluorescence anisotropies (rs) using diphenylhexatriene as a probe. The Ca(2+)-ATPase activity was determined by assaying the amount of inorganic phosphate (Pi) released from ATP. It was found that the membrane fluidity (rs: 0.154 +/- 0.014 vs 0.113 +/- 0.010, P < 0.01) and Ca(2+)-ATPase activity (3.1 +/- 1.3 vs 25.3 +/- 2.4 mumol Pi.h-1/mg protein, P < 0.01) were reduced in SR exposed to H2O2 (2 mmol.L-1) for 40 min. Catalase 20 micrograms.ml-1 completely prevented the SR damages caused by H2O2. H2O2 jeopardized the SR in a concentration- and time-dependent manner as measured by changes in rs values and Ca(2+)-ATPase activities, which were negatively correlated (r = 0.981, P < 0.01). These results suggest that H2O2 produces dysfunctions of the rabbit myocardial SR, and that the alteration of membrane fluidity may be one of the mechanisms responsible for the decrease of Ca(2+)-ATPase activity.

Production of intracellular enzyme by Corynebacterium glutamicum T6-13 protoplasts immobilized in Ca-alginate gels

The glutamate dehydrogenase (GDH) (EC 1.4.1.4) productivity of the immobilized Corynebacterium glutamicum T6-13 protoplasts in Ca-alginate gels was investigated. GDH in Corynebacterium glutamicum T6-13 cells is an intracellular enzyme. The cells pretreated with 0.5 U/l-1 penicillin G were used for the preparation of protoplasts. Protoplasts were prepared by treating these cells with lysozyme at 30 degrees C for 14 h in 0.5 M NaCl solution and separating the protoplasts. Protoplasts were directly immobilized in 3% Ca-alginate gels (method I). The immobilized protoplasts could be also prepared by treating the immobilized whole cells with lysozyme (method II); this method was more convenient than method I. The GDH productivity of the immobilized protoplasts amounted to 205% of that of the free cells (intracellular). The immobilized protoplasts could be repeatedly used for at least 6 batches (18 days) and had good storage stability.