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71.
Erwinia herbicola strain Eh1087 produces the broad-spectrum phenazine antibiotic D-alanylgriseoluteic acid (AGA). In this report, a cluster of 16 ehp (Erwinia herbicola phenazine) plasmid genes required for the production of AGA by Eh1087 is described. The extent of the gene cluster was revealed by the isolation of 82 different Eh1087 AGA- mutants, all found to possess single mini-Tn5lacZ2 insertions within a 14 kbp DNA region. Additional transposon insertions that did not affect antibiotic production by Eh1087 were created to define the boundaries of the gene cluster. The size and location of genes between these boundaries were derived from a combination of DNA sequence analyses, minicell protein analyses and the correlation between mutation position and the production of coloured AGA intermediates by many ehp mutants. Precursor-feeding and complementation experiments resulted in 15 ehp genes being assigned to one of four functional groups according to their role in the synthesis of AGA. Group 1 is required for the synthesis of the phenazine nucleus in the form of antibiotic precursor one (AP1, phenazine-1,6-dicarboxylic acid). Group 2 is responsible for conversion of AP1 to AP2, which is subsequently modified to AP3 (griseoluteic acid) and exported by the group 3 gene products. Group 4 catalyses the addition of D-alanine to AP3 to create AGA, independently of groups 1, 2 and 3. A gene that is divergently transcribed from the 15 AGA synthesis ehp genes confers resistance to AGA. 相似文献
72.
Metal binding by algae has enormous potential for environmental bioremediation targeting towards detoxification of water bodies. The present work reports the use of live and dead Spirulina sp. for sorption of metals like Cr(3+), Ni(2+), Cu(2+), and Cr(6+) in form of Cr(2)O(7)(2-). Preliminary investigation shows that this biomass takes up substantial amount of metal ions indicated above. IR spectroscopic study, kinetics models, Langmuir and Freundlich adsorption isotherms, SEM analysis, and fluorescence microscopic study of Spirulina sp. and the Spirulina sp. treated with different metal ions have been employed to understand the sorption mechanism. It is hoped that live Spirulina sp. will be a strong candidate for management of industrial wastewater. 相似文献
73.
Ushasri Chilakamarthi Jaipal Kandhadi Srinivas Gunda Avinash Raj Thatipalli Mahesh Kumar Jerald Giribabu Lingamallu Rakesh C. Reddy Arabinda Chaudhuri Gopal Pande 《Experimental cell research》2014
Targeted molecular imaging to detect changes in the structural and functional organization of tissues, at the molecular level, is a promising approach for effective and early diagnosis of diseases. Quantitative and qualitative changes in type I collagen, which is a major component in the extra cellular matrix (ECM) of skin and other vital organs like lung, liver, heart and kidneys, are often associated with the pathophysiology of these organs. We have synthesized a fluorescent probe that comprises collagelin, a specific collagen binding peptide, coupled to fluorescent porphyrin that can effectively detect abnormal deposition of collagen in live tissues by emitting fluorescence in the near infra red (NIR) region. In this report we have presented the methodology for coupling of 5-(4-carboxy phenyl)-10, 15, 20-triphenyl porphyrin (C-TPP) to the N-terminal of collagelin or to another mutant peptide (used as a control). We have evaluated the efficacy of these fluorescent peptides to detect collagen deposition in live normal and abnormal tissues. Our results strongly suggest that porphyrin-tagged collagelin can be used as an effective probe for the non invasive in vivo detection of tissue fibrosis, especially in the liver. 相似文献
74.
75.
Sanjoy Kumar Mahanty Rajkishor Khaware Shehnaz Ansari Poonam Gupta Rajendra Prasad 《FEMS microbiology letters》1991,84(2):163-166
Phosphate uptake studies in different strains of the dimorphic pathogenic yeast Candida albicans were undertaken to show that this yeast actively transported phosphate with an apparent Km in the range of 90-170 microM. The uptake was pH dependent and derepressible under phosphate starvation. Vanadate-resistant (van) mutants of C. albicans showed a 20-70% reduction in the rate of phosphate uptake in high phosphate medium and was associated with an increased Km and reduced Vmax. The magnitude of derepression under phosphate starvation was different between van mutants. These results demonstrate that van mutants may have developed resistance by modifying the rate of entry of vanadate. 相似文献
76.
Neuroprotective effects of genistein in VSC4.1 motoneurons exposed to activated microglial cytokines
McDowell ML Das A Smith JA Varma AK Ray SK Banik NL 《Neurochemistry international》2011,59(2):175-184
Pro-inflammatory cytokines released from activated microglia may be responsible for neuronal damage and resulting motor deficits associated with CNS disorders such as spinal cord injury, Parkinson’s disease, and multiple sclerosis. Estrogen (17β-estradiol) is capable of ameliorating motoneuron death following spinal cord injury, but has a number of deleterious side effects. Genistein (GEN), an estrogen receptor beta agonist and potent antioxidant, may represent an alternative to estrogen in treating neurodegenerative disorders. However, little is known about the neuroprotective effects of GEN. We therefore tested whether GEN would prevent apoptosis in cultured motoneurons following exposure to pro-inflammatory cytokines released from IFN-γ activated microglia. Exposure of ventral spinal cord 4.1 motoneurons to microglial cytokine supernatant in vitro caused significant apoptosis and reduced mitochondrial membrane potential. An increase in reactive oxygen species, intracellular Ca2+, calpain, caspases, cytochrome c, and the bax:bcl-2 ratio were also noted. GEN treatment reversed apoptotic death and cellular changes following cytokine exposure and was associated with increased expression of estrogen receptor β suggesting that GEN may promote neuroprotection via receptor-mediated pathways. The addition of ICI 182, 780, an estrogen receptor antagonist following GEN treatment attenuated neuroprotection, suggesting that GEN may act mainly via estrogen receptor β to protect VSC4.1 motoneurons. We conclude that GEN protects cultured ventral spinal cord 4.1 cells from inflammatory insult and thus may represent a potential beneficial therapy in the treatment of neurodegenerative disorders. 相似文献
77.
Metenou S Dembele B Konate S Dolo H Coulibaly YI Diallo AA Soumaoro L Coulibaly ME Coulibaly SY Sanogo D Doumbia SS Traoré SF Mahanty S Klion A Nutman TB 《Journal of immunology (Baltimore, Md. : 1950)》2011,186(8):4725-4733
The mechanisms underlying the modulation of both the malaria-specific immune response and the course of clinical malaria in the context of concomitant helminth infection are poorly understood. We used multiparameter flow cytometry to characterize the quality and the magnitude of malaria-specific T cell responses in filaria-infected and -uninfected individuals with concomitant asymptomatic Plasmodium falciparum malaria in Mali. In comparison with filarial-uninfected subjects, filarial infection was associated with higher ex vivo frequencies of CD4(+) cells producing IL-4, IL-10, and IL-17A (p = 0.01, p = 0.001, and p = 0.03, respectively). In response to malaria Ag stimulation, however, filarial infection was associated with lower frequencies of CD4(+) T cells producing IFN-γ, TNF-α, and IL-17A (p < 0.001, p = 0.04, and p = 0.04, respectively) and with higher frequencies of CD4(+)IL10(+)T cells (p = 0.0005). Importantly, filarial infection was associated with markedly lower frequencies of malaria Ag-specific Th1 (p < 0.0001), Th17 (p = 0.012), and "TNF-α" (p = 0.0008) cells, and a complete absence of malaria-specific multifunctional Th1 cells. Filarial infection was also associated with a marked increase in the frequency of malaria-specific adaptive regulatory T/Tr1 cells (p = 0.024), and the addition of neutralizing anti-IL-10 Ab augmented the amount of Th1-associated cytokine produced per cell. Thus, among malaria-infected individuals, concomitant filarial infection diminishes dramatically the frequencies of malaria-specific Th1 and Th17 T cells, and alters the quality and magnitude of malaria-specific T cell responses. 相似文献
78.
Mónica J. Pajuelo María Eguiluz Eric Dahlstrom David Requena Frank Guzmán Manuel Ramirez Patricia Sheen Michael Frace Scott Sammons Vitaliano Cama Sarah Anzick Dan Bruno Siddhartha Mahanty Patricia Wilkins Theodore Nash Armando Gonzalez Héctor H. García Robert H. Gilman Steve Porcella Mirko Zimic Cysticercosis Working Group in Peru 《PLoS neglected tropical diseases》2015,9(12)
Background
Infections with Taenia solium are the most common cause of adult acquired seizures worldwide, and are the leading cause of epilepsy in developing countries. A better understanding of the genetic diversity of T. solium will improve parasite diagnostics and transmission pathways in endemic areas thereby facilitating the design of future control measures and interventions. Microsatellite markers are useful genome features, which enable strain typing and identification in complex pathogen genomes. Here we describe microsatellite identification and characterization in T. solium, providing information that will assist in global efforts to control this important pathogen.Methods
For genome sequencing, T. solium cysts and proglottids were collected from Huancayo and Puno in Peru, respectively. Using next generation sequencing (NGS) and de novo assembly, we assembled two draft genomes and one hybrid genome. Microsatellite sequences were identified and 36 of them were selected for further analysis. Twenty T. solium isolates were collected from Tumbes in the northern region, and twenty from Puno in the southern region of Peru. The size-polymorphism of the selected microsatellites was determined with multi-capillary electrophoresis. We analyzed the association between microsatellite polymorphism and the geographic origin of the samples.Results
The predicted size of the hybrid (proglottid genome combined with cyst genome) T. solium genome was 111 MB with a GC content of 42.54%. A total of 7,979 contigs (>1,000 nt) were obtained. We identified 9,129 microsatellites in the Puno-proglottid genome and 9,936 in the Huancayo-cyst genome, with 5 or more repeats, ranging from mono- to hexa-nucleotide. Seven microsatellites were polymorphic and 29 were monomorphic within the analyzed isolates. T. solium tapeworms were classified into two genetic groups that correlated with the North/South geographic origin of the parasites.Conclusions/Significance
The availability of draft genomes for T. solium represents a significant step towards the understanding the biology of the parasite. We report here a set of T. solium polymorphic microsatellite markers that appear promising for genetic epidemiology studies. 相似文献79.
Arabinda Das M. Kelly Guyton Amena Smith Gerald Wallace IV Misty L. McDowell Denise D. Matzelle Swapan K. Ray Naren L. Banik 《Journal of neurochemistry》2013,124(1):133-146
Optic neuritis (ON), which is an acute inflammatory autoimmune demyelinating disease of the central nervous system (CNS), often occurs in multiple sclerosis (MS). ON is an early diagnostic sign in most MS patients caused by damage to the optic nerve leading to visual dysfunction. Various features of both MS and ON can be studied following induction of experimental autoimmune encephalomyelitis (EAE), an animal model of MS, in Lewis rats. Inflammation and cell death in the optic nerve, with subsequent damage to the retinal ganglion cells in the retina, are thought to correlate with visual dysfunction. Thus, characterizing the pathophysiological changes that lead to visual dysfunction in EAE animals may help develop novel targets for therapeutic intervention. We treated EAE animals with and without the calpain inhibitor calpeptin (CP). Our studies demonstrated that the Ca2+‐activated neutral protease calpain was upregulated in the optic nerve following induction of EAE at the onset of clinical signs (OCS) of the disease, and these changes were attenuated following treatment with CP. These reductions correlated with decreases in inflammation (cytokines, iNOS, COX‐2, and NF‐κB), and microgliosis (i.e. activated microglia). We observed that calpain inhibition reduced astrogliosis (reactive astroglia) and expression of aquaporin 4 (AQP4). The balance of Th1/Th2 cytokine production and also expression of the Th1‐related CCR5 and CXCR3 chemokine receptors influence many pathological processes and play both causative and protective roles in neuron damage. Our data indicated that CP suppressed cytokine imbalances. Also, Bax:Bcl‐2 ratio, production of tBid, PARP‐1, expression and activities of calpain and caspases, and internucleosomal DNA fragmentation were attenuated after treatment with CP. Our results demonstrated that CP decreased demyelination [loss of myelin basic protein (MBP)] and axonal damage [increase in dephosphorylated neurofilament protein (de‐NFP)], and also promoted intracellular neuroprotective pathways in optic nerve in EAE rats. Thus, these data suggest that calpain is involved in inflammatory as well as in neurodegenerative aspects of the disease and may be a promising target for treating ON in EAE and MS. 相似文献
80.
Chaudhry Y Nayak A Bordeleau ME Tanaka J Pelletier J Belsham GJ Roberts LO Goodfellow IG 《The Journal of biological chemistry》2006,281(35):25315-25325
Two classes of viruses, namely members of the Potyviridae and Caliciviridae, use a novel mechanism for the initiation of protein synthesis that involves the interaction of translation initiation factors with a viral protein covalently linked to the viral RNA, known as VPg. The calicivirus VPg proteins can interact directly with the initiation factors eIF4E and eIF3. Translation initiation on feline calicivirus (FCV) RNA requires eIF4E because it is inhibited by recombinant 4E-BP1. However, to date, there have been no functional studies carried out with respect to norovirus translation initiation, because of a lack of a suitable source of VPg-linked viral RNA. We have now used the recently identified murine norovirus (MNV) as a model system for norovirus translation and have extended our previous studies with FCV RNA to examine the role of the other eIF4F components in translation initiation. We now demonstrate that, as with FCV, MNV VPg interacts directly with eIF4E, although, unlike FCV RNA, translation of MNV RNA is not sensitive to 4E-BP1, eIF4E depletion, or foot-and-mouth disease virus Lb protease-mediated cleavage of eIF4G. We also demonstrate that both FCV and MNV RNA translation require the RNA helicase component of the eIF4F complex, namely eIF4A, because translation was sensitive (albeit to different degrees) to a dominant negative form and to a small molecule inhibitor of eIF4A (hippuristanol). These results suggest that calicivirus RNAs differ with respect to their requirements for the components of the eIF4F translation initiation complex. 相似文献