Isolation and characterization of brassinosteroids from immature seeds of Camellia sinensis (O) Kuntze

Brassinosteroids play an important role in growth and development of plants. They have been reported universally in all the plants. The present study deals with the presence of these compounds in immature tea seeds. Five brassinosteroids, i.e. 6-deoxo-28-norcathasterone, 6-deoxo-28-norteasterone, 3-dehydro-6-deoxo-28-norteasterone, 6-deoxo-28-nortyphasterol and 6-deoxo-28-norcastasterone have been isolated and identified by GC–MS. The identified brassinosteroids and their derivatives are active constituents of late C-6 oxidation pathway, thereby suggesting the biosynthesis of brassinosteroids in tea seeds by late C-6 oxidation pathway.     

Mapping of the Rf-3 nuclear fertility-restoring gene for WA cytoplasmic male sterility in rice using RAPD and RFLP markers

The cytoplasmic male sterility (CMS) of wild-abortive (WA) cytoplasm has been widely used for breeding hybrid rice. Two restorer genes for the CMS have been found by traditional genetic analysis. To tag the restorer genes we used a set of near-isogenic lines (NILs) of Zhenshan 97 carrying different genotypes for fertility restoration from IR24, to perform RAPD analysis. From the survey of 720 random primers, six RAPD markers were identified to be associated with Rf-3. Three of these OPK05-800, OPU10-1100 and OPW01-350, were mapped on chromosome 1. Two populations from the crosses between Zhenshan 97 A and a near-isogenic restorer line ZSR21 and between Zhenshan 97 A and IR24 were used for mapping Rf-3. The three RAPD markers and three RFLP markers, RG532, RG140 and RG458, were found to be closely linked to Rf-3 in the two populations. The same location of Rf-3 was also found in a population from the cross of IR58025 A//IR36/IR58025 B. At the RG532 locus, different alleles were found between two CMS lines, Zhenshan 97 A and IR58025 A, and between two restorer lines, IR24 and IR36. The use of these molecular markers closely linked to Rf-3 in facilitating the development of hybrid rice is discussed. Received: 3 January 1996 / Accepted: 17 May 1996     

Small molecular weight G-protein, H-Ras, and retinal endothelial cell apoptosis in diabetes

We have demonstrated that the expressions of small molecular weight G-protein, H-Ras, and its effector protein, Raf-1, are increased in the retina in diabetes, and the specific inhibitors of Ras function inhibit glucose-induced apoptosis of retinal capillary cells. This study is to examine the contributory roles for H-Ras in glucose-induced apoptosis of retinal endothelial cells by genetic manipulation of functionally active H-Ras levels. Bovine retinal endothelial cells were transfected with the plasmids of either wild type (WT), constitutively active (V12) or dominant-negative (N17) H-Ras. Glucose-induced increase in apoptosis, nitric oxide (NO) levels and activation of NF-κB and caspase-3 were determined in these genetically manipulated cells. Exposure of bovine retinal endothelial cells to 20 mM glucose significantly increased H-Ras activation as determined by Raf-1 binding assay. Overexpression of V12 in the endothelial cells further increased their glucose-induced apoptosis by 40%, NO levels by about 50%, and activated NF-κB and caspase-3 by about 30–40% compared to the untransfected cells incubated in 20 mM glucose. In contrast, overexpression of the inactive mutant, N17, inhibited glucose-mediated increases in apoptotic cell death, NO levels and NF-κB and caspase-3 activation; the values were significantly different (p < 0.02) compared to those obtained from the untransfected cells incubated under similar conditions. Our findings demonstrate that H-Ras activation is important in the activation of the specific signaling events leading to the accelerated retinal capillary cell apoptosis in hyperglycemic conditions, suggesting the possible use of H-Ras inhibitors to inhibit the pathogenesis of diabetic retinopathy.     

Human DNA helicase IV is nucleolin, an RNA helicase modulated by phosphorylation

The cDNA encoding human DNA helicase IV (HDH IV), a 100-kDa protein which unwinds DNA in the 5′ to 3′ direction with respect to the bound strand, was cloned and sequenced. It was found to be identical to the human cDNA encoding nucleolin, a ubiquitous eukaryotic protein essential for pre-ribosome assembly. HDH IV/nucleolin can unwind RNA-RNA duplexes, as well as DNA-DNA and DNA-RNA duplexes. Phosphorylation of HDH IV/nucleolin by cdc2 kinase and casein kinase II enhanced its unwinding activity in an additive way. The Gly-rich C-terminal domain possesses a limited ATP-dependent duplex-unwinding activity which contributes to the helicase activity of HDH IV/nucleolin.     

CD8+ T cells primed in the periphery provide time-bound immune-surveillance to the central nervous system

After vaccination, memory CD8(+) T cells migrate to different organs to mediate immune surveillance. In most nonlymphoid organs, following an infection, CD8(+) T cells differentiate to become long-lived effector-memory cells, thereby providing long-term protection against a secondary infection. In this study, we demonstrated that Ag-specific CD8(+) T cells that migrate to the mouse brain following a systemic Listeria infection do not display markers reminiscent of long-term memory cells. In contrast to spleen and other nonlymphoid organs, none of the CD8(+) T cells in the brain reverted to a memory phenotype, and all of the cells were gradually eliminated. These nonmemory phenotype CD8(+) T cells were found primarily within the choroid plexus, as well as in the cerebrospinal fluid-filled spaces. Entry of these CD8(+) T cells into the brain was governed primarily by CD49d/VCAM-1, with the majority of entry occurring in the first week postinfection. When CD8(+) T cells were injected directly into the brain parenchyma, cells that remained in the brain retained a highly activated (CD69(hi)) phenotype and were gradually lost, whereas those that migrated out to the spleen were CD69(low) and persisted long-term. These results revealed a mechanism of time-bound immune surveillance to the brain by CD8(+) T cells that do not reside in the parenchyma.     

Evaluation of some adamantane-based synthetic trioxanes against Plasmodium knowlesi in rhesus monkeys

In our search for synthetic substitutes for artemisinin and its derivatives we had earlier prepared a series of adamantane-based 1, 2, 4-trioxanes 5a-c which had shown promising activity against P. berghei in Swiss mice. We have further evaluated these and two new compounds (5d-e) against Plasmodium knowlesi W1, a virulent malaria parasite in rhesus monkeys, in the dose range of 40-80 mg/kg x 5 days by intramuscular route. Trioxanes 5b and 5c showed 100% protection and cure at 80 mg/kg x 5 days, while trioxane 5a showed 71% cure at this dose. Detailed studies again showed 50% curative effect of 5a at 40 mg/kg x 5 days treatment.     

Y418C: a novel mutation in exon 9 of the glucocerebrosidase gene of a patient with Gaucher disease creates a new Bgl I site

We report a novel mutation in exon 9 of the glucocerebrosidase gene of a patient with Gaucher disease and of Sardinian origin.     

Expression of noncoding vault RNA in human malignant cells and its importance in mitoxantrone resistance

Several noncoding RNAs do vital cellular functions, including gene regulation and cell differentiation. Previously, we reported that vault RNA (vRNA) has the ability to recognize chemotherapeutic compounds, such as mitoxantrone, based on biophysical and biochemical analyses. In the present study, we show that human glioblastoma-, leukemia-, and osteocarcinoma-derived cell lines overexpress vRNA and exhibit higher resistance toward mitoxantrone. Interestingly, when vRNA expression was suppressed by RNA interference in these cells, the resistance progressively decreased. In agreement with these findings, overexpression of vRNA-1 caused resistance to mitoxantrone. These results suggest a role of vRNA in mitoxantrone resistance in malignant cells and justify further studies on the importance and application of noncoding RNAs in cancer chemotherapeutics.