BRI1 is a critical component of a plasma-membrane receptor for plant steroids

Most multicellular organisms use steroids as signalling molecules for physiological and developmental regulation. Two different modes of steroid action have been described in animal systems: the well-studied gene regulation response mediated by nuclear receptors, and the rapid non-genomic responses mediated by proposed membrane-bound receptors. Plant genomes do not seem to encode members of the nuclear receptor superfamily. However, a transmembrane receptor kinase, brassinosteroid-insensitive1 (BRI1), has been implicated in brassinosteroid responses. Here we show that BRI1 functions as a receptor of brassinolide, the most active brassinosteroid. The number of brassinolide-binding sites and the degree of response to brassinolide depend on the level of BRI1 protein. The brassinolide-binding activity co-immunoprecipitates with BRI1, and requires a functional BRI1 extracellular domain. Moreover, treatment of Arabidopsis seedlings with brassinolide induces autophosphorylation of BRI1, which, together with our binding studies, shows that BRI1 is a receptor kinase that transduces steroid signals across the plasma membrane.

Sylvian fissure and medial temporal lobe structures in patients with schizophrenia: a magnetic resonance imaging study

Volumes of the medial temporal lobe structures (i.e. the amygdala, hippocampus, and parahippocampal gyrus), Sylvian fissure, and inferior horn of the lateral ventricle relative to the cerebral hemisphere were measured in 24 patients with schizophrenia and 23 normal controls using magnetic resonance imaging. The patients had significantly larger Sylvian fissures and inferior horns bilaterally than the controls. In the patients the right Sylvian fissure size showed a significant positive correlation with the duration of illness. Moreover, earlier onset of illness was significantly correlated with decreased volume of the left medial temporal lobe structures. These results replicate previous finding of inferior horn enlargement and suggest the significance of the Sylvian fissure and the medial temporal lobe structures in pathophysiology of schizophrenia.

Transient accumulation of jasmonic acid during the synchronized hypersensitive cell death in Tobacco mosaic virus-infected tobacco leaves

Jasmonic acid (JA) transiently accumulated during temperature-dependent synchronous necrotic lesion formation in Tobacco mosaic virus-infected tobacco leaves. The accumulation of JA was preceded by activation of a tobacco mitogen-activated protein kinase, WIPK, which functions upstream of JA in wound signal transduction pathways.

An unusual isopentenyl diphosphate isomerase found in the mevalonate pathway gene cluster from Streptomyces sp. strain CL190

A gene cluster encoding five enzymes of the mevalonate pathway had been cloned from Streptomyces sp. strain CL190. This gene cluster contained an additional ORF, orfD, encoding an unknown protein that was detected in some archaebacteria and some Gram-positive bacteria including Staphylococcus aureus. The recombinant product of orfD was purified as a soluble protein and characterized. The molecular mass of the enzyme was estimated to be 37 kDa by SDS-polyacrylamide gel electrophoresis and 155 kDa by gel filtration chromatography, suggesting that the enzyme is most likely to be a tetramer. The purified enzyme contained flavin mononucleotide (FMN) with the amount per tetramer being 1.4 to 1.6 mol/mol. The enzyme catalyzed the isomerization of isopentenyl diphosphate (IPP) to produce dimethylallyl diphosphate (DMAPP) in the presence of both FMN and NADPH. The Escherichia coli plasmid expressing orfD could complement the disrupted IPP isomerase gene in E. coli. These results indicate that orfD encodes an unusual IPP isomerase showing no sequence similarity to those of IPP isomerases identified to date. Based on the difference in enzymatic properties, we classify the IPP isomerases into two types: Type 2 for FMN- and NAD(P)H-dependent enzymes, and type 1 for the others. In view of the critical role of this isomerase in S. aureus and of the different enzymatic properties of mammalian (type 1) and S. aureus (type 2) isomerases, this unusual enzyme is considered to be a suitable molecular target for the screening of antibacterial drugs specific to S. aureus.

Structure-activity relationships within a family of selectively cytotoxic macrolide natural products

[figure: see text] We describe a semi-synthetic deglycosylated derivative of apoptolidin that retains considerable activity against the mitochondrial ATPase but has greatly reduced cellular cytotoxicity. We also demonstrate that a related antifungal natural product, cytovaricin, inhibits the same molecular target. Structural comparison of these macrolides provides insights into their conserved features that are presumably important for biological activity and identifies promising avenues at the interface of organic synthesis and biosynthesis for the generation of new selective cytotoxic agents.

Characterization of inhibitory action of concanamycins against herpes simplex virus

Concanamycins A (Conmy A) and B (Conmy B), well-known inhibitors of the vacuolar proton-ATPase, were isolated from the culture broth of Streptomyces sp. strain FK51 as antiherpetic agents. These compounds showed potent inhibition of herpes simplex virus type 1 (HSV-1) replication in an in vitro assay system, having antiviral activities with 50% inhibitory concentrations of 0.072 and 0.51 ng/ml for Conmy A and Conmy B, respectively. While the attachment of HSV-1 to Vero cells was not inhibited, both of the compounds blocked the penetration of virus into host cells. When added to the late stages of virus replication, the concanamycins also exerted marked inhibitory effects on the production of viruses. Release of progeny viruses was found to be suppressed by the agents. SDS-PAGE analysis of isotope-labelled HSV-specific proteins revealed that the synthesis of beta proteins was moderately inhibited and some of the glycoproteins were synthesized with reduced molecular weights. Western blot analysis using antibodies against two HSV-specific glycoproteins (gC and gD) showed differences in their syntheses between untreated and Conmy A-treated cells. Syncytium formation by HSV-1 strain HF was inhibited, and small plaques with rounded cells were formed in Conmy A-treated cell cultures. When wild-type HSV-1 was serially propagated under the selective pressure of Conmy A, and the resulting progeny viruses were grown in drug-free medium, their plaque morphology of syncytium and sensitivity to Conmy A were the same as those of parent virus. From these findings, antiherpetic activities of Conmy A and B might be mainly dependent on their activities as vacuolar proton-ATPase inhibitors with intracellular translocation of glycoproteins and the inhibition of the maturation of virus glycoproteins.

Clinical value of sequential subtraction scintigraphy with 99mTc-RBC for gastrointestinal bleeding

OBJECTIVE

To evaluate the clinical value of sequential subtraction scintigraphy (SSS) with 99mTc red blood cell (RBC) for the early detection of gastrointestinal (GI) bleeding.

METHODS

Ninety patients referred with clinical evidence of GI bleeding underwent 99mTc-RBC scintigraphy with digital gamma camera after labeling of 99mTc-RBC in vivo. Sequential 12 conventional non-subtraction (CNS) images of abdomen were taken at 5 min intervals for 60 min. Then 5-min images were subsequently subtracted from each other using a computer and 11 subtracted images were obtained. Delayed images up to 24 hr were obtained when early results were negative and/or recurrent bleeding was suspected.

RESULTS

62 of 90 patients with suspected GI bleeding were conformed to have active hemorrhage up to 24 hr. The scintigrams were divided into the following three sets: within 30 min, 60 min, and 24 hr. The sensitivity of SSS was 87% (54/62, 30 min) and 91.9% (57/62, 60 min) respectively, which were significantly higher (P < 0.05) than that of CNS (56.4%, 35/62 and 62.9%, 39/62). 24 hr delayed image of CNS increased the sensitivity to 85.4%. No significant difference in specificity between the two methods was noted. Of the 62 patients with definite active hemorrhage, the bleeding sites were identified by surgical operation in 42. The concordant rate with surgical operation in SSS was 92.8% (39/42), higher than that of CNS (73.8%, 31/42).

CONCLUSIONS

Sequential subtraction scintigraphy with 99mTc-RBC, compared with conventional non-subtraction scintigraphy, is an effective technique for the early detection of GI bleeding. It increases the diagnostic sensitivity, detecting a small amount of bleeding earlier than CNS; SSS reduces background activity, more accurtely localizing bleeding sites. It also shortens the examination time, making this approach more suitable for pediatric, elderly and critically ill patients.

The Effect of Dietary Carotenoids on Lung Tumorigenesis Induced by Intratracheally Instillated Diesel Exhaust Particles

The purpose of this study is to examine the carotenoid effects on lung tumorigenesis induced by intratracheal instillation of diesel exhaust particles (DEP) into mice weekly for 20 wk. It was suggested that active oxygen radicals might play an important role in DEP-induced lung tumorigenesis. Mice were divided to 4 groups of diet containing 0.02% of palm oil carotene, 0.02% of beta-carotene, or no carotenoid with or without DEP. The BF group (4% fat) and the HF group (16% fat) were prepared for each diet group. The experimental period was 12 mo. By the administration of palm oil carotene, neither adenocarcinoma nor adenoma was found in the BF group. In the HF group with palm oil carotene, no adenocarcinoma was observed, and adenoma was reduced. Adenoma in the HF group was not greatly reduced by beta-carotene, but rather increased in the BF group. No adenocarcinoma was found in either the BF or the HF groups with beta-carotene. The 8-hydroxydeoxyguanosine/deoxyguanosine ratio in palm carotene groups was lower than in the other groups, while that in beta-carotene groups was not. From these results, palm oil carotene was suggested to prevent lung tumorigenesis by its protective effect on DNA from active oxygen. Beta-carotene was supposed to have different effects from palm oil carotene on lung tumorigenesis. Besides the chemopreventive effect, the growth of mice was inhibited by the administration of palm oil carotene. Further studies are necessary to elucidate the mechanisms of carotenoid effects.

A case of retroperitoneal extramedullary plasmacytoma with multiple metastases

We investigated a patient with extramedullary plasmacytoma in the retroperitoneal space with multiple metastases using abdominal CT scan and 67Ga scintigraphy. Abdominal enhanced CT revealed the retroperitoneal tumor mimicking lymphoma. 67Ga scintigraphy showed multiple tumor localization. We could detect retroperitoneal extramedullary plasmacytoma with multiple metastases using 67Ga scintigraphy. This retroperitoneal tumor may appear similar to lymphoma on CT.

Functional evaluation of hydronephrosis by diffusion-weighted MR imaging. Relationship between apparent diffusion coefficient and split glomerular filtration rate

PURPOSE

To determine the relationship between apparent diffusion coefficient (ADC) values measured by diffusion-weighted MR imaging and split renal function determined by renal scintigraphy in patients with hydronephrosis.

MATERIAL AND METHODS

Diffusion-weighted imaging on a 1.5 T MR unit and renal scintigraphy were performed in 36 patients with hydronephrosis (45 hydronephrotic kidneys, 21 non-hydronephrotic kidneys). ADC values of the individual kidneys were measured by diffusion-weighted MR imaging. Split renal function (glomerular filtration rate (GFR)) was determined by renal scintigraphy using 99mTc-DTPA. The relationship between ADC values and split GFR was examined in 66 kidneys. The hydronephrotic kidneys were further classified into three groups (severe renal dysfunction, GFR <10 ml/min, n=7; moderate renal dysfunction, GFR 10-25 ml/min, n= 10; normal renal function, GFR >25 ml/ min, n=28), and mean values for ADCs were calculated.

RESULTS

In hydronephrotic kidneys, there was a moderate positive correlation between ADC values and split GFR (R2=0.56). On the other hand, in nonhydronephrotic kidneys, poor correlation between ADC values and split GFR was observed (R2=0.08). The mean values for ADCs of the dysfunctioning hydronephrotic kidneys (severe renal dysfunction, 1.32 x 10(-3) +/- 0.18 x 10(-3) mm2/s; moderate renal dysfunction, 1.38 x 10(-3) +/- 0.10 x 10(-3) mm2/s) were significantly lower than that of the normal functioning hydronephrotic kidneys (1.63 x 10(-3) +/- 0.12 +/- 10(-3) mm2/s).

CONCLUSION

These results indicated that measurement of ADC values by diffusion-weighted MR imaging has a potential value in the evaluation of the functional status of hydronephrotic kidneys.

Detecting meningeal carcinomatosis from breast cancer with thallium-201 SPECT

Thallium-201 (201Tl) scintigraphy is one of the imaging methods used in the detection of various tumors including brain metastasis. We evaluated a patient with meningeal carcinomatosis from breast cancer by using 201Tl single-photon emission computed tomography (SPECT). Meningeal spread of a tumor was noted on enhanced CT. SPECT revealed tumor localization in meningeal carcinomatosis. These results suggest that SPECT with 201Tl may be useful in detecting meningeal carcinomatosis from breast cancer.

Gliosarcoma with thallium-201 SPECT

Thallium-201 (201Tl) chloride scintigraphy is the imaging method use for the detection of various tumors including glioblastoma, but only limited information on 201Tl uptake in gliosarcoma is available. We investigated a patient with gliosarcoma by means of 201Tl single-photon emission computed tomography (SPECT) and MRI. SPECT imaging revealed high 201Tl uptake in the tumor, which was closely correlated with contrast-enhancement on MRI. These results suggest that SPECT with 201Tl may be useful for detecting gliosarcoma and provide physiological information on this tumor.

Analysis of the expression of CLA1, a gene that encodes the 1-deoxyxylulose 5-phosphate synthase of the 2-C-methyl-D-erythritol-4-phosphate pathway in Arabidopsis

The discovery of the 2-C-methyl-D-erythritol-4-phosphate pathway for the biosynthesis of isoprenoids raises the important question of the nature and regulation of the enzymes involved in this pathway. CLA1, a gene previously isolated from Arabidopsis, encodes the first enzyme of the 2-C-methyl-D-erythritol-4-phosphate pathway, 1-deoxy-D-xylulose-5-phosphate synthase. We demonstrate this enzyme activity by complementation of the cla1-1 mutant phenotype and by direct enzymatic assays. Based on mRNA and protein expression patterns this enzyme is expressed mainly in developing photosynthetic and non-photosynthetic tissues. The beta-glucuronidase expression pattern driven from the CLA1 gene regulatory region supports the northern and protein data while also showing that this gene has some level of expression in most tissues of the plant. A mutation in the CLA1 gene interferes with the normal development of chloroplasts and etioplasts, but does not seem to affect amyloplast structure. Microscopic analysis also shows a pleiotropic effect of the CLA1 gene mutation in mesophyll tissue formation.

Synthesis of 6-oxy functionalized campest-4-en-3-ones: efficient hydroperoxidation at C-6 of campest-5-en-3-one with molecular oxygen and silica gel

As a reference compound library for the investigation of biosynthesis of brassinosteroids, focused on a pathway from campesterol (1) to campestanol (2), 6-oxy functionalized campest-4-en-3-ones as well as campest-5-en-3-one (7) and campestane-3,6-dione were prepared from 1. Oxidation of 1 with pyridinium chlorochromate buffered by calcium carbonate gave 5-en-3-one (7) in 76% yield. Treatment of 7 with silica gel under an oxygen atmosphere in ethyl ether at room temperature produced efficient hydroperoxidation at the C-6 position to give 6alpha-hydroperoxycampest-4-en-3-one and 6beta-hydroperoxycampest-4-en-3-one in 34% and 49% yields, respectively. These compounds were converted to 6alpha-hydroxycampest-4-en-3-one and 6beta-hydroxycampest-4-en-3-one by reduction with triethyl phosphite. This provided the first example of the practical use of hydroperoxidation at C-6 of a Delta(5(6))-unsaturated 3-oxo-steroid with molecular oxygen and silica gel. On the other hand, oxidation of 1 with pyridinium chlorochromate in the absence of calcium carbonate gave campest-4-ene-3,6-dione in 64% yield. This compound was then converted in a highly stereoselective manner to campestane-3,6-dione with A/B trans ring junction by reduction with titanium (III) chloride in 85% yield.

Diheteropeptin, a novel substance with TGF-beta-like activity, produced by a fungus, Diheterospora chlamydosporia. II. Physico-chemical properties and structure elucidation

The structure of diheteropeptin (1), a TGF-beta-like active substance from Diheterospora chlamydosporia Q58044, was determined to be a new cyclotetrapeptide, cyclo[2aminoisobutyryl-(S)-phenylalanyl-(R)-prolyl-(2S,8R,9R)-2-am ino-8,9-dihydroxydecanoyl-] by NMR, mass spectrometric and chemical studies.

Diheteropeptin, a new substance with TGF-beta-like activity, produced by a fungus, Diheterospora chlamydosporia. I. Production, isolation and biological activities

A new metabolite, diheteropeptin, was found in the culture broth of Diheterospora chlamydosporia Q58044 by screening for TGF-beta-like active substances. Diheteropeptin was extracted from the culture supernatant and purified by a series of chromatographies such as silica gel, gel filtration and HPLC. Diheteropeptin exhibited cytostatic activity in Mv1Lu cells with an IC50 value of 20.3 microM and inhibited histone deacetylase.

In vitro sensitivity of human endometrial cancer cell lines to paclitaxel or irinotecan (CPT-11) in combination with other aniticancer drugs

We have evaluated the growth inhibitory effects of paclitaxel alone or irinotecan (CPT-11) alone and their combined effects with other drugs on human endometrial cancer cell lines. IC50 doses of paclitaxel (Tx), SN-38 (active metabolite of CPT-11; 7-ethyl-10-hydroxycamptothecin) and cisplatin, including other drugs which have been used for treatment of patients with endometrial cancer, were examined using five human endometrial cancer cell lines (Ishikawa, HEC-1A, HEC-50B, HEC-59 and HEC-108). When in vitro sensitivity was defined IC50 lower than 10% of the peak plasma concentration (PPC), all endometrial cancer cell lines were sensitive to paclitaxel and three of five endometrial cancer cell lines were sensitive to SN-38, whereas cisplatin was not active against any endometrial cancer cell lines used in this study. Regarding the other drugs, aclarubicin (ACR) and actinomycin D (ACD) were active against four of five endometrial cancer cell lines, etoposide (VP-16) and pirarubicin (THP) against two, and 5-fluorouracil (5-FU) against only one, while ifosfamide (4-OHIFO) was not active against any endometrial cancer cell lines. When combined effects of paclitaxel or SN-38 with other one drug were determined by the median-effect analysis, paclitaxel followed by cisplatin resulted in synergistic effects to all endometrial cancer cell lines. Paclitaxel followed by SN-38 also had synergistic effects to four cell lines. Sequential but not simultaneous administration of taxol and THP-adriamycin showed synergistic effects to three cell lines. In combinations of SN-38 with other drugs, simultaneous administration of SN-38 and cisplatin resulted in synergistic effects to all cell lines. It is noteworthy that ACD followed by SN-38 showed synergistic effects to all cell lines, and simultaneous treatment of ACD and SN-38 or SN-38 followed by ACD also resulted in synergistic effects to three cell lines. THP-adriamycin followed by SN-38 had synergistic effects to four cell lines. The present quantitative data analysis for synergism provides a basis for a rational design of clinical protocols for combination chemotherapy in patients with endometrial cancer of the uterus.

A gene cluster for the mevalonate pathway from Streptomyces sp. Strain CL190

A biosynthetic 3-hydroxy-3-methylglutaryl coenzyme A reductase (EC 1. 1.1.34), the rate-limiting enzyme of the mevalonate pathway for isopentenyl diphosphate biosynthesis, had previously been purified from Streptomyces sp. strain CL190 and its corresponding gene (hmgr) had been cloned (S. Takahashi, T. Kuzuyama, and H. Seto, J. Bacteriol. 181:1256-1263, 1999). Sequence analysis of the flanking regions of the hmgr gene revealed five new open reading frames, orfA to -E, which showed similarity to those encoding eucaryotic and archaebacterial enzymes for the mevalonate pathway. Feeding experiments with [1-(13)C]acetate demonstrated that Escherichia coli JM109 harboring the hmgr gene and these open reading frames used the mevalonate pathway under induction with isopropyl beta-D-thiogalactopyranoside. This transformant could grow in the presence of fosmidomycin, a potent and specific inhibitor of the nonmevalonate pathway, indicating that the mevalonate pathway, intrinsically absent in E. coli, is operating in the E. coli transformant. The hmgr gene and orfABCDE are thus unambiguously shown to be responsible for the mevalonate pathway and to form a gene cluster in the genome of Streptomyces sp. strain CL190.