Alstiphyllanines I-O, ajmaline type alkaloids from Alstonia macrophylla showing vasorelaxant activity

Seven new ajmaline type alkaloids, alstiphyllanines I-O (1-7) were isolated from the leaves of Alstonia macrophylla together with six related alkaloids (8-13). Structures and stereochemistry of 1-7 were fully elucidated and characterized by 2D NMR analysis. A series of alstiphyllanines I-O (1-7) as well as the known ajmaline type alkaloids (8-13) showed that they relaxed phenylephrine (PE)-induced contractions against rat aortic ring. Among them, vincamedine (10) showed potent vasorelaxant activity, which may be mediated through inhibition of Ca(2+) influx through voltage-dependent Ca(2+) channels (VDCs) and/or receptor-operated Ca(2+) channels (ROCs) as well as partially mediated the NO release from endothelial cells. The presence of substituents at both N-1 and C-17 may be important to show vasorelaxation activity.     

A Computational analysis on Lectin and Histone H1 protein of different pulse species as well as comparative study with rice for balanced diet

The issue of balanced nutrition is of great concern to human. Meat and fish are the best sources of protein. The affordability of these resources for people in developing countries is less. Thus, there is an increasing interest in pulses and its derivates as an alternative to fish and meat. Lectin and histone H1 are the most common proteins in various pulses and our interest is in identifying the dominant essential amino acids in them for use as supplements. However, actin and lectin are common among Oryza Sativa and cicer arietinum. We describe the amount of lectin and histone H1 in cicer arietinum, Lens culinaris and Pisum sativum in a comparative manner. cicer arietinum was found to contain more essential amino acids than Lens culinaris and Pisum sativum. The secondary structures of lectin and histone H1 protein were analyzed to gain functional inferences in these species. The comparative study shows the relatively poor presence of the amino acid methionine in most pulses. However, Oryza Sativa was found to contain sufficient methionine. The study shows that pulses (especially cicer arietinum) were a suitable alternative source to meat and fish for Lectin and Histone H1 balance. Hence, pulses could be suggested with rice for balanced protein diet.     

Characterization of hydrophobic-ligand-binding proteins of Taenia solium that are expressed specifically in the adult stage

SUMMARY Taenia solium, a causative agent of taeniasis and cysticercosis, has evolved a repertoire of lipid uptake mechanisms. Proteome analysis of T. solium excretory-secretory products (TsESP) identified 10 kDa proteins displaying significant sequence identity with cestode hydrophobic-ligand-binding-proteins (HLBPs). Two distinct 362- and 352-bp-long cDNAs encoding 264- and 258-bp-long open reading frames (87 and 85 amino acid polypeptides) were isolated by mining the T. solium expressed sequence tags and a cDNA library screening (TsHLBP1 and TsHLBP2; 94% sequence identity). They clustered into the same clade with those found in Moniezia expansa and Hymenolepis diminuta. Genomic structure analysis revealed that these genes might have originated from a common ancestor. Both the crude TsESP and bacterially expressed recombinant proteins exhibited binding activity toward 1-anilinonaphthalene-8-sulfonic acid (1,8-ANS), which was competitively inhibited by oleic acid. The proteins also bound to cis-parinaric acid (cPnA) and 16-(9-anthroyloxy) palmitic acid (16-AP), but showed no binding activity against 11-[(5-dimethylaminonaphthalene-1-sulfonyl) amino] undecanoic acid (DAUDA) and dansyl-DL-α-aminocaprylic acid (DACA). Unsaturated fatty acids (FAs) showed greater affinity than saturated FAs. The proteins were specifically expressed in adult worms throughout the strobila. The TsHLBPs might be involved in uptake and/or sequestration of hydrophobic molecules provided by their hosts, thus contributing to host-parasite interface interrelationships.     

Does lycopene offer human LDL any protection against myeloperoxidase activity?

Lycopene is a lipophilic antioxidant that is largely transported in human blood by Low Density Lipoproteins (LDL). One of the early events in the aetiology of atherosclerosis is thought to be the oxidation of LDL. Myeloperoxidase an enzyme secreted by neutrophils and macrophages is thought to oxidise human LDL particles. In this study, isolated human LDL was challenged with myeloperoxidase or copper, and the LDL was screened for lipoperoxidation and oxidation of apolipoprotein B100, depletion of lycopene and oxidation of cholesterol. Myeloperoxidase induced oxidation of LDL through direct interaction with apolipoprotein B100. No lipoperoxidation was observed following myeloperoxidase treatment; however, 7-ketocholesterol was detected indicating the products of myeloperoxidase interact with the surface of the LDL particles. Lycopene does react with the products of myeloperoxidase in solvent, but played no role in protecting against enzyme derived oxidation of human LDL.     

A novel treatment strategy for ovarian cancer based on immunization against zona pellucida protein (ZP) 3

We tested the principle of treating malignant ovarian tumors by vaccination against their ectopically expressed protein, zona pellucida glycoprotein (ZP) 3, using as the experimental model the granulosa cell tumors that develop in transgenic mice expressing the simian virus 40 T-antigen under the inhibin-α promoter (inhα/Tag). We found high ZP3 expression in granulosa cell tumors of the transgenic mice, in human surface ovarian cancer and granulosa cell lines, and in human granulosa cell tumors and their metastases. Early preventive immunization (between 2 and 5.5 mo of age) of transgenic mice with recombinant human (rh) ZP3 prevented ovarian tumorigenesis, and delayed therapeutic immunization (between 4.5 and 7 mo) reduced weights of existing tumors by 86 and 75%, respectively (P<0.001), compared to vehicle-treated control mice. No objective side effects of the immunizations were observed. Liver metastases were found in nontreated/vehicle-treated controls (n=7/39), but none following active rhZP3 immunizations (n=0/36; P<0.05). Immunization with rhZP3 was highly effective, as demonstrated by the induction of anti-ZP3 antibodies, as well as proliferative responses to the ZP3 antigen. These results signal rhZP3 immunization as a novel strategy to be developed for the immunotherapy of ovarian granulosa cell tumors, as well as for that of other malignancies that may express ZP3.     

Inhibitory effects of methylglyoxal on light-induced stomatal opening and inward K+ channel activity in Arabidopsis

Methylglyoxal (MG) is a reactive aldehyde derived by glycolysis. In Arabidopsis, MG inhibited light-induced stomatal opening in a dose-dependent manner. It significantly inhibited both inward-rectifying potassium (K(in)) channels in guard-cell protoplasts and an Arabidopsis K(in) channel, KAT1, heterologously expressed in Xenopus oocytes. Thus it appears that MG inhibition of stomatal opening involves MG inhibition of K(+) influx into guard cells.     

Novel Ocimumoside A and B as anti-stress agents: modulation of brain monoamines and antioxidant systems in chronic unpredictable stress model in rats

Therapies targeting central stress mechanisms are fundamental for the development of successful treatment strategies. Ocimum sanctum (OS) is an Indian medicinal plant traditionally used for the treatment of various stress-related conditions. Previously, we have isolated and characterized three OS compounds; Ocimarin, Ocimumoside A and Ocimumoside B. However, their role in modulating chronic stress-induced central changes is unexplored. Thus, in the present study the efficacy of these OS compounds have been evaluated on the chronic unpredictable stress (CUS)-induced alterations in the monoaminergic and antioxidant systems in the frontal cortex, striatum and hippocampus, along with the changes in the plasma corticosterone levels. CUS (two different types of stressors daily for seven days) resulted in a significant elevation of plasma corticosterone level, which was reversed to control levels by pretreatment with Ocimumoside A and B (40 mg/kg p.o.), while Ocimarin showed no effect. The levels of NA, DA and 5-HT were significantly decreased in all the three brain regions by CUS, with a selective increase of DA metabolites. A significant decrease in the glutathione (GSH) content, the activities of superoxide dismutase and catalase with a significant increase in the glutathione peroxidase activity and lipid peroxidation was observed in all the three regions of the brain by CUS. The OS compounds alone did not cause any significant change in the baseline values of these parameters. However, Ocimumoside A and B (40 mg/kg body p.o.) attenuated these CUS-induced alterations with an efficacy similar to that of standard anti-stress (Panax quinquefolium; 100 mg/kg p.o.) and antioxidant (Melatonin; 20 mg/kg i.p.) drugs. While, Ocimarin failed to modulate these CUS-induced alterations. Therefore, this is the first report which identified the anti-stress activity of novel Ocimumoside A and B at the level of central monoamines and antioxidant properties, implicating their therapeutic importance in the prevention of stress-related disorders.     

Regulation of Ethylene Biosynthesis Under Salt Stress in Red Pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.) by 1-Aminocyclopropane-1-Carboxylic Acid (ACC) Deaminase-producing Halotolerant Bacteria

The present study was carried out to understand the mechanism of salt stress amelioration in red pepper plants by inoculation of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-producing halotolerant bacteria. In general, ethylene production, ACC concentration, ACC synthase (ACS), and ACC oxidase (ACO) enzyme activities increased with increasing levels of salt stress. Treatment with halotolerant bacteria reduced ethylene production by 47–64%, ACC concentration by 47–55% and ACO activity by 18–19% in salt-stressed (150 mmol NaCl) red pepper seedlings compared to uninoculated controls. ACS activity was lower in red pepper seedlings treated with Bacillus aryabhattai RS341 but higher in seedlings treated with Brevibacterium epidermidis RS15 (44%) and Micrococcus yunnanensis RS222 (23%) under salt-stressed conditions as compared to uninoculated controls. A significant increase was recorded in red pepper plant growth under salt stress when treated with ACC deaminase-producing halotolerant bacteria as compared to uninoculated controls. The results of this study collectively suggest that salt stress enhanced ethylene production by increasing enzyme activities of the ethylene biosynthetic pathway. Inoculation with ACC deaminase-producing halotolerant bacteria plays an important role in ethylene metabolism, particularly by reducing the ACC concentration, although a direct effect on reducing ACO activity was also observed. It is suggested that growth promotion in inoculated red pepper plants under inhibitory levels of salt stress is due to ACC deaminase activity present in the halotolerant bacteria.     

Comparative analysis of the molecular mechanisms controlling the initiation of chromosomal DNA replication in yeast and in mammalian cells

In eukaryotes DNA replication takes place in the S phase of the cell cycle. It initiates from hundreds to thousands of replication origins in a coordinated manner, in order to efficiently duplicate the genome. The sequence of events leading to the onset of DNA replication is conventionally divided in two interdependent processes: licensing-a process during which replication origins acquire replication competence but are kept inactive- and firing-a process during which licensed origins are activated but not re-licensed. In this review we investigate the evolutionary conservation of the molecular machinery orchestrating DNA replication initiation both in yeast and in mammalian cells, highlighting a remarkable conservation of the general architecture of this central biological mechanism. Many steps are conserved down to molecular details and are performed by orthologous proteins with high sequence conservation, while differences in molecular structure of the performing proteins and their interactions are apparent in other steps. Tight regulation of initiation of DNA replication is achieved through protein phosphorylation, exerted mostly by Cyclin-dependent kinases in order to ensure that each chromosome is fully replicated once, and only once, during each cycle, and to avoid the formation of aberrant DNA structures and incorrect chromosomal duplication, that in mammalian cells are a prerequisite for genome instability and tumorigenesis. We then consider a molecular mathematical model of DNA replication, recently proposed by our group in a collaborative project, as a frame of reference to discuss similarities and differences observed in the regulatory program controlling DNA replication initiation in yeast and in mammalian cells and discuss whether they may be dependent upon different functional constraints. We conclude that a systems biology approach, integrating molecular analysis with modeling and computational investigations, is the best choice to investigate the control of DNA replication in mammalian cells.