Occurrence of a Clover Proliferation (16SrVI) Group Phytoplasma Associated with Little Leaf Disease of Portulaca grandiflora in India

Portulaca grandiflora (family Portulacaceae), commonly known as moss rose purslane, is a popular ornamental plant widely grown in temperate climates because it blooms all summer. Portulaca is also used for medicinal purposes since it is rich in vitamins A, B1, and C and has antimicrobial and cytotoxic activity. Since March 2005, 30 to 50% of P. grandiflora plants in the ornamental gardens as well as in pots at the Central Institute of Medicinal and Aromatic Plants, Lucknow, India have displayed symptoms resembling phytoplasma infection. Disease symptoms start as a typical bud proliferation, downward curling, and diminishing size of leaves, followed by overall stunted growth and yellowing of the whole plant from April to June. Some plants also formed rosettes and a proliferation of axillary shoots resulting in a witches'-broom appearance. Typical pleomorphic bodies, mostly spherical to oval, ranging from 340 to 1,100 nm were observed only in sieve elements of infected plants by transmission electron microscopy (TEM). On the basis of symptoms, TEM observations, PCR, and response to antibiotic treatment, the causal organism was identified as phytoplasma (1). Total genomic DNA from healthy and infected plants was extracted with the CTAB buffer method (2). Of 27 suspected samples screened by PCR, 23 were phytoplasma positive. Presence of phytoplasmas in plants was demonstrated by a nested PCR assay employing primer pair P1/P6 followed by R16F2n/R16R2 that generated rDNA products of 1.5 and 1.2 kb, respectively, only from symptomatic plants. No differences among phytoplasmas in Portulaca plants were detected by restriction fragment length polymorphism (RFLP) analysis of nested rDNA (1.2 kb) products using endonucleases BamHI, RsaI, AluI, HpaII, and EcoRI. Comparative analysis of RFLP patterns with those derived from reference phytoplasmas tentatively identified the Portulaca little leaf (PLL) phytoplasma as a member of 16S rDNA RFLP group 16SrVI (3). A nested PCR product (1.25 kb) was cloned with a TOPO TA cloning kit (Invitrogen, Carlsbad, CA) and sequenced. The sequence was deposited in the GenBank database (Accession No. EF651786). Sequence analysis revealed the PLL phytoplasma to be most similar (98%) to Indian brinjal little leaf (Accession No. EF186820) and 'Candidatus Phytoplasma trifolii' (Accession No. AY390261), two 16SrVI group phytoplasmas previously reported from India and Canada, respectively. The status of PLL (EF651786) was also verified by in silico RFLP analysis (4) of the F2n/R2 sequence of six closely related strains (Accession Nos. AF228052, AY390261, AY270156, AY409070, AY409069, and EF186820) of the 16SrVI group using 17 restriction enzymes (AluI, BamHI, BfaI, BsfUI, DraI, EcoRI, HaeIII, HhaI, HinfI, HpaI, HpaII, KpnI, MseI, Sau3AI, RsaI, SspI, and TaqI). In silico restriction digestion and virtual gel plotting showed similar patterns for all enzymes. To our knowledge, this is the first report of a 16SrVI group phytoplasma infecting Portulaca plants in India. References: (1) P. V. Ajayakumar et al. Aust. Plant Dis. Notes 2:67, 2007. (2) S. P. S. Khanuja et al. Plant Mol. Biol. Rep. 17:74, 1999. (3) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (4) W. Wei et al. Int. J. Syst. Evol. Mic. 57:1855, 2007.

Gastroprotective effect of standardized extract of Ficus glomerata fruit on experimental gastric ulcers in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Traditionally fruits of Ficus glomerata Roxb (Family: Moraceae) are used to treat anemia and gastrointestinal disorders.

AIM

Gastroprotective effect of 50% ethanolic extract of F. glomerata fruit (FGE) was studied in different gastric ulcer models in rats.

METHODS

FGE (50, 100 and 200 mg/kg body weight) was administered orally, twice daily for 5 days for prevention from pylorus ligation (PL), ethanol (EtOH) and cold restraint stress (CRS)-induced ulcers. Estimation of H+K+ATPase activity and gastric wall mucous were performed in EtOH-induced ulcer and antioxidant enzyme activities in supernatant mitochondrial fraction of CRS-induced ulcers.

RESULTS

FGE showed dose dependent inhibition of ulcer index in pylorus ligation, ethanol and cold restraint stress-induced ulcers. FGE prevents the oxidative damage of gastric mucosa by blocking lipid peroxidation and by significant decrease in superoxide dismutase, H+K+ATPase and increase in catalase activity. High performance thin layer chromatography (HPTLC) analysis showed the presence of 0.57% and 0.36% w/w of gallic acid and ellagic acid in FGE.

CONCLUSIONS

Our results show that F. glomerata possess significant gastroprotective activity which might be due to gastric defence factors and phenolics might be the main constituents responsible for this activity.

Morphological differences in semicrystalline polymers: Implications for local dynamics and chain diffusion

Morphological differences in semicrystalline polymers due to different crystallization conditions have implications for the chain motion. The local dynamics in the noncrystalline regions of solution-crystallized linear polyethylene is lower than in a melt-crystallized sample, but the opposite is observed for chain diffusion between noncrystalline and crystalline regions. The activation enthalpy for chain diffusion, however, is the same, indicating that entropic differences in the noncrystalline regions strongly influence the chain diffusion of the same polymer in different morphologies.

Glut-1 antibodies induce growth arrest and apoptosis in human cancer cell lines

Glucose transporters (Gluts) facilitate glucose uptake and tumors frequently over express the Gluts, especially Glut-1. Breast cancer and lung cancer (NSCLC) cell lines were incubated with anti-Glut-1 antibodies alone or with cisplatin, paclitaxel or gefitinib. Inhibition of proliferation and apoptosis was assessed. Antibodies to Glut-1 inhibited proliferation by 50% and 75% in the tested NSCLC and breast cancer cell lines, respectively. They also potentiate the anti-proliferative effects of cisplatin, paclitaxel and gefitinib. Our results indicate that anti-Glut-1 antibodies inhibit proliferation and induce apoptosis in the evaluated cell lines and provide preliminary evidence of their anti-tumor activity.

Protective effect of Ocimum sanctum on 3-methylcholanthrene, 7,12-dimethylbenz(a)anthracene and aflatoxin B1 induced skin tumorigenesis in mice

A study on the protective effect of alcoholic extract of the leaves of Ocimum sanctum on 3-methylcholanthrene (MCA), 7,12-dimethylbenzanthracene (DMBA) and aflatoxin B1 (AFB1) induced skin tumorigenesis in a mouse model has been investigated. The study involved pretreatment of mice with the leaf extract prior to either MCA application or tetradecanoyl phorbol acetate (TPA) treatment in a two-stage tumor protocol viz a viz, DMBA/TPA and AFB1/TPA. The results of the present study indicate that the pretreatment with alcoholic extract of the leaves of O. sanctum decreased the number of tumors in MCA, DMBA/TPA and AFB1/TPA treated mice. The skin tumor induced animals pretreated with alcoholic extract led to a decrease in the expression of cutaneous gamma-glutamyl transpeptidase (GGT) and glutathione-S-transferase-P (GST-P) protein. The histopathological examination of skin tumors treated with leaf extract showed increased infiltration of polymorphonuclear, mononuclear and lymphocytic cells, decreased ornithine decarboxylase activity with concomitant enhancement of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) in the serum, implying the in vivo antiproliferative and immunomodulatory activity of leaf extract. The decrease in cutaneous phase I enzymes and elevation of phase II enzymes in response to topical application of leaf extract prior to MCA, AFB1, DMBA/TPA and AFB1/TPA treatment indicate the possibility of impairment in reactive metabolite(s) formation and thereby reducing skin carcinogenicity. Furthermore, pretreatment of leaf extract in the carcinogen induced animals resulted in elevation of glutathione levels and decrease in lipid peroxidation along with heat shock protein expression, indicating a scavenging or antioxidant potential of the extract during chemical carcinogenesis. Thus it can be concluded that leaf extract of O. sanctum provides protection against chemical carcinogenesis in one or more of the following mechanisms: (i) by acting as an antioxidant; (ii) by modulating phase I and II enzymes; (iii) by exhibiting antiproliferative activity.

Migration-promoting role of VEGF-C and VEGF-C binding receptors in human breast cancer cells

Vascular endothelial growth factor C (VEGF-C) is a lymphangiogenic factor over-expressed in highly metastatic, cyclooxygenase (COX)-2 expressing breast cancer cells. We tested the hypothesis that tumour-derived VEGF-C may play an autocrine role in metastasis by promoting cellular motility through one or more VEGF-C-binding receptors VEGFR-2, VEGFR-3, neuropilin (NRP)-1, NRP-2, and integrin alpha9beta1. We investigated the expression of these receptors in several breast cancer cell lines (MDA-MB-231, Hs578T, SK-BR-3, T-47D, and MCF7) and their possible requirement in migration of two VEGF-C-secreting, highly metastatic lines MDA-MB-231 and Hs578T. While cell lines varied significantly in their expression of above VEGF-C receptors, migratory activity of MDA-MB-231 and Hs578T cells was linked to one or more of these receptors. Depletion of endogenous VEGF-C by treatments with a neutralising antibody, VEGF-C siRNA or inhibitors of Src, EGFR/Her2/neu and p38 MAP kinases which inhibited VEGF-C production, inhibited cellular migration, indicating the requirement of VEGF-C for migratory function. Migration was differentially attenuated by blocking or downregulation of different VEGF-C receptors, for example treatment with a VEGFR-2 tyrosine kinase inhibitor, NRP-1 and NRP-2 siRNA or alpha9beta1 integrin antibody, indicating the participation of one or more of the receptors in cell motility. This novel role of tumour-derived VEGF-C indicates that breast cancer metastasis can be promoted by coordinated stimulation of lymphangiogenesis and enhanced migratory activity of breast cancer cells.

The prevalence and clinical relevance of sexual dysfunction in women and men with chronic heart failure

Sexual dysfunction is a common problem of increasing incidence that is associated with multiple co-morbid conditions and chronic diseases. In heart failure, however, exact numbers are unknown, in part secondary to under-reporting and under-interrogating by health care providers. A gender-specific questionnaire was modified from established sexual dysfunction questionnaires to correspond to a non-randomized outpatient heart failure population, to assess the prevalence and demographic distribution of sexual dysfunction and potential treatments expectations. One-hundred patients in a stable hemodynamic condition in New York Heart Association classes I-III participated. Eighty-seven percent of women were diagnosed with female sexual dysfunction compared to 84% of men with erectile dysfunction. Eighty percent of women reported reduced lubrication, which resulted in frequent unsuccessful intercourse in 76%. Thirty-six percent of patients thought that sexual activity could harm their current cardiac condition; 75% of females and 60% of men stated that no physicians ever asked about potential sexual problems. Fifty-two percent of men considered sexual activity in their current condition as an essential aspect of quality of life and 61% were interested in treatment to improve sexual function. Sexual dysfunction appears to be high in prevalence in both men and women with chronic compensated heart failure and represents a reduction in quality of life for most. Despite the fact that most patients are interested in receiving therapy to improve sexual dysfunction, treatment options are rarely discussed or initiated.

Differential regulation of human YY1 and caspase 7 promoters by prohibitin through E2F1 and p53 binding sites

Prohibitin is a 30 kDa growth suppressive protein that has pleiotropic functions in the cell. Although prohibitin has been demonstrated to have potent transcriptional regulatory functions, it has also been proposed to facilitate protein folding in the mitochondria and promote cell migration in association with Raf-1. Our previous studies have shown that prohibitin physically interacts with the marked-box domain of E2F family members and represses their transcriptional activity; in contrast, prohibitin could bind to and enhance the transcriptional activity of p53. Here, we show that promoters of human YY1 (Yin and Yang 1) as well as caspase 7 genes are modulated by prohibitin. YY1 promoter activity was reduced upon overexpression of prohibitin, while it was enhanced when prohibitin was depleted by small interfering RNA techniques. The repressive effects of prohibitin on the YY1 promoter were mediated through E2F binding sites, as seen by mutational analysis and chromatin immunoprecipitation assays. Further, depletion of E2F1 prevented prohibitin from repressing the YY1 promoter. In contrast with YY1, prohibitin overexpression led to enhanced levels of caspase 7, whereas depletion of prohibitin reduced it. Interestingly, the caspase 7 promoter was found to have p53-binding sites and prohibitin activated this promoter through p53. These studies show that prohibitin can have diverse effects on the expression of different genes and the activity of various cellular promoters is affected by prohibitin. Further, it appears very likely that prohibitin carries out many of its cellular functions by affecting the transcription of different genes.

Treatment of aneurysmal bone cysts with percutaneous sclerotherapy using polidocanol. A review of 72 cases with long-term follow-up

Aneurysmal bone cyst is a rare tumour-like lesion which develops during growth. Our aim was to determine the efficacy of the administration of percutaneous intralesional 3% polidocanol (hydroxypolyaethoxydodecan) as sclerotherapy. Between July 1997 and December 2004 we treated 72 patients (46 males, 26 females) with a histologically-proven diagnosis of aneurysmal bone cyst, at various skeletal sites using this method. The sclerotherapy was performed under fluoroscopic guidance and general anaesthesia or sedation and local anaesthesia. The mean follow-up period was 34 months (26.5 to 80). The patients were evaluated using the Enneking system for functional assessment and all the lesions were radiologically quantified into four grades. The mean age of patients was 15.6 years (3 to 38) and the mean number of injections was three (1 to 5). Ten patients were cured by a single injection. The mean reduction in size of the lesion (radiological healing) was found to be 76.6% (61.9% to 93.2%) with a mean clinical response of 84.5% (73.4% to 100%). Recurrence was seen in two patients (2.8%) within two years of treatment and both were treated successfully by further sclerotherapy. Percutaneous sclerotherapy with polidocanol is a safe alternative to conventional surgery for the treatment of an aneurysmal bone cyst. It can be used at surgically-inaccessible sites and treatment can be performed on an out-patient basis.

Nicotine induces cell proliferation by beta-arrestin-mediated activation of Src and Rb-Raf-1 pathways

Recent studies have shown that nicotine, a component of cigarette smoke, can stimulate the proliferation of non-neuronal cells. While nicotine is not carcinogenic by itself, it has been shown to induce cell proliferation and angiogenesis. Here we find that mitogenic effects of nicotine in non-small cell lung cancers (NSCLCs) are analogous to those of growth factors and involve activation of Src, induction of Rb-Raf-1 interaction, and phosphorylation of Rb. Analysis of human NSCLC tumors show enhanced levels of Rb-Raf-1 complexes compared with adjacent normal tissue. The mitogenic effects of nicotine were mediated via the alpha7-nAChR subunit and resulted in enhanced recruitment of E2F1 and Raf-1 on proliferative promoters in NSCLC cell lines and human lung tumors. Nicotine stimulation of NSCLC cells caused dissociation of Rb from these promoters. Proliferative signaling via nicotinic acetylcholine receptors (nAChRs) required the scaffolding protein beta-arrestin; ablation of beta-arrestin or disruption of the Rb-Raf-1 interaction blocked nicotine-induced proliferation of NSCLCs. Additionally, suppression of beta-arrestin also blocked activation of Src, suppressed levels of phosphorylated ERK, and abrogated Rb-Raf-1 binding in response to nicotine. It appears that nicotine induces cell proliferation by beta-arrestin-mediated activation of the Src and Rb-Raf-1 pathways.

Prohibitin facilitates cellular senescence by recruiting specific corepressors to inhibit E2F target genes

Prohibitin is a growth regulatory gene that has pleiotropic functions in the nucleus, mitochondria, and cytoplasmic compartments. Earlier studies had proposed a role for prohibitin in modulating cellular senescence, but the underlying mechanisms remain unknown. Here we show that senescence induced by DNA-damaging agents causes the localization of prohibitin to specific heterochromatic foci. Prohibitin could bind to heterochromatin protein 1 (HP1) family proteins and colocalized with HP1gamma in senescence-associated heterochromatic foci. Further, HP1gamma could synergize with prohibitin to repress E2F1-mediated transcriptional activity. The depletion of prohibitin by small interfering RNA or antisense techniques led to a reduction in the senescent phenotype, correlating with a reduced expression of senescence-associated beta-galactosidase and fewer numbers of senescence-associated heterochromatic foci. Chromatin immunoprecipitation assays showed that prohibitin is needed for the recruitment of HP1gamma to E2F1-regulated proliferative promoters, leading to their repression. The ablation of prohibitin prevented the recruitment of HPIgamma, but not Suv39H, to the promoters upon senescence. Prohibitin-mediated recruitment of HP1gamma occurred in only senescent cells, not in quiescent cells; thus, there is a dichotomy in the recruitment of different corepressors by prohibitin, depending on the type of growth arrest. These studies show that prohibitin plays a vital role in inducing cellular senescence.

The effects of chronic phosphodiesterase-5 inhibitor use on different organ systems

Phosphodiesterase-5 (PDE-5) inhibitors selectively inhibit PDE-5 enzymes that are present in various tissues like penile tissue, platelets, vascular, and smooth muscle tissue. The drug's actions on these tissues have lead to the successful therapeutic use in patients suffering from conditions such as erectile dysfunction (ED) and pulmonary hypertension. PDE-5 inhibitors (PDE-5i) act on the erectile tissue causing penile smooth muscle relaxation and vasodilatation leading to penile erection. In addition, in particular when used in conjunction with prostaglandin inhibitors, PDE-5i cause vasodilatation in pulmonary vasculature hence decreasing both the pulmonary arterial pressure and resistance. PDE-5i have also shown to mildly decrease blood pressure, increase cardiac index, and increase coronary blood flow in experimental animals as well as in human studies. The Food and Drug Administration (FDA) has approved three PDE-5i for the treatment of ED: sildenafil (Viagra), vardenafil (Levitra), and tadalafil (Cialis) and one for pulmonary hypertension: sildenafil (Revatio). These agents are highly selective for PDE-5 enzymes as compared to other subclasses of PDE enzymes and have the almost identical pharmacological action but slightly different pharmacokinetics. Only little data exist about long-term use of PDE-5i and their effects on different organ system. This paper reviews the current information available on chronic PDE-5 inhibitor use.

Melting kinetics in polymers

In polymers, it is possible to obtain single chain forming single crystals. It is feasible to melt these crystals by simple consecutive detachment of chain segments from the crystalline substrate and its diffusion into the melt. However, complication in the melting process occurs when the chain in the process of detachment from the surface is shared between different crystals. Experimentally, a clear distinction in different melting processes is observed, by the differences in the activation energies required for the consecutive detachment of chain segments or of segments having topological constraints. The consecutive detachment of free chain segments starts at the melting temperature predicted from the Gibbs-Thomson equation, whereas higher temperature or time is required if the chain has to overcome the constraints.

Molecular blending by polymerization of intercalated solvent. Poly(gamma-benzyl-L-glutamate)/benzyl methacrylate as a model system

The aim of the present research is to obtain blending between a polymer and a (polymerized) solvent on the molecular level. Because of its rigid rod structure, poly(gamma-benzyl-L-glutamate) (PBLG) is chosen as the polymer. Benzyl methacrylate (BzMA) has been chosen as the solvent for two reasons. First, the structure of the solvent is very similar to the structure of the side chain of PBLG, favoring interactions between the two materials. Second, the solvent can be polymerized, because of the presence of a C=C bond. In cast films of PBLG and BzMA separate zones of the polymer and solvent are present. Wide-angle X-ray diffraction and Raman results show that upon heating the cast films homogenization occurs and solvent molecules intercalate between the helices of PBLG. At 150 degrees C a hexagonal packing is obtained. The dimensions of the obtained packing depend on the solvent concentration, which confirms that solvent molecules are indeed present within the crystalline lattice. DSC experiments imply that the observed changes upon heating correspond to thermodynamic processes. On cooling the homogeneous samples, disordering of the hexagonal packing occurs. Polymerization of the homogeneous samples results in a disordering of the hexagonal packing and in a contraction of the unit cell. The latter once more confirms that solvent molecules are indeed present within the crystalline lattice. The applied principle of polymerization of a solvent in a molecular homogeneous system can be favorable for many applications, for which morphology control at the molecular level is required.

Skin tumorigenic potential of aflatoxin B1 in mice

Aflatoxin B1 (AFB1) has been classified as a category I human carcinogen, which is responsible for a high incidence of hepatocellular carcinoma. Since exposure to AFB1 can occur through skin contact in addition to ingestion and inhalation, the carcinogenic potential of topically applied AFB1 on mouse skin was investigated. Our results show that single topical application of AFB1 (80 nmol) as a tumor initiator, followed by twice weekly application of 12-tetradecanoyl phorbol myristate acetate (TPA, 4 nmol), resulted in tumor formation after 13 weeks. However, no tumorigenic potential was observed when AFB1 (16 nmol) was used either as a complete carcinogen or as a tumor promoter (4 nmol). Histological analysis of skin showed squamous cell carcinoma in the AFB1/TPA treated group. The application of AFB1 as a complete carcinogen, an initiator or a promoter after 24 weeks demonstrated widespread degenerative and necrotic changes in hepatic tissue as well, suggesting liver to be the target organ following percutaneous absorption. Additionally, twice weekly topical application of AFB1 caused significant induction of cutaneous CYP IA monoxygenases without any effect on hepatic levels while glutathione-S-transferase activity was induced more in the liver than skin. The topical application of AFB1 also resulted in increased hepatic and cutaneous lipid peroxidation with concomitant depletion of glutathione content. It is likely that due to higher induction of hepatic GST activity, products of lipid peroxidation may be detoxified and therefore unable to cause DNA damage making mice resistant to hepatic tumor formation. The overall results indicate a tumor initiating potential of AFB1 in mice and suggest that continued dermal exposure of AFB1, even at low doses, might lead to degenerative changes in hepatocytes.