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Synthesis of silver and gold nanoparticles from leaf of Litchi chinensis and its biological activities

Asian Pacific Journal of Tropical Biomedicine 2018年第3期8卷 142-149页

作者： Uzma Murad Barkatullah Shafqat Ali Khan Muhammad Ibrar Sami Ullah Umbreen Khattak department of Botany Faculty of Biological Sciences Islamia College department of Botany Faculty of Biological Sciences University of Peshawar

Objective: To synthesize and isolate silver and gold nanoparticles from Litchi chinensis leaf methanolic extract, and to evaluate its comparative biological activities including muscles relaxant, analgesic, anti-inflammatory and antidiarrheal. Methods: The gold and silver nanoparticles were synthesized by dissolving methanolic extract in gold chloride and silver nitrate solution separately which were confirmed by colour change and UV-Vis spectroscopy, and pellets were collected through centrifugation. biological activities of the extract were conducted on BALB/c mice through various standard methods and the data were subjected to One-way ANOVA. Results: The colorless gold chloride solution changed to purple soon after the addition of plant extract, demonstrating that the reaction took place and gold ions were reduced to gold nanoparticles, while colorless silver nitrate solution changed to light and dark brown that was indicative of silver nanoparticles. The muscles relaxant activity showed that silver nanoparticles were more effective than gold nanoparticles and methanolic extract in traction test. The analgesic activity showed that silver and gold nanoparticles showed highest percentage decrease in acetic acid induced writhing at the doses of 50, 100 and 150 mg/kg b.w. The highest anti-inflammatory activity was produced by gold nanoparticles followed by silver nanoparticles, while low activity was observed in methanolic leaf extract. Only the crude methanolic extract showed significant antidiarrheal activity as compared to the standard drug atropine sulphate, while antidiarrheal activities of gold and silver nanoparticles were non-significant. Conclusions: The present work concludes that isolated silver and gold nanoparticles from leaf methanolic extract shows strong muscles relaxant, analgesic and anti-inflammatory activities while crude methanolic extract possesses good antidiarrheal activity.

关键词： Litchi chinensis Methanolic extract Silver and gold nanoparticles Muscles relaxant Analgesic Anti-inflammatory Antidiarrheal activities

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Effect of biofilm formation by clinical isolates of Helicobacter pylori on the efflux-mediated resistance to commonly used antibiotics

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World Journal of Gastroenterology 2017年第7期23卷 1163-1170页

作者： Bahareh Attaran Tahereh Falsafi Nassim Ghorbanmehr department of Microbiology Faculty of Biological SciencesAlzahra University department of Biotechnology Faculty of Biological SciencesAlzahra University

To evaluate the role of biofilm formation on the resistance of Helicobacter pylori (H. pylori) to commonly prescribed antibiotics, the expression rates of resistance genes in biofilm-forming and planktonic cells were *** collection of 33 H. pylori isolates from children and adult patients with chronic infection were taken for the present study. The isolates were screened for biofilm formation ability, as well as for polymerase chain reaction (PCR) reaction with HP1165 and hp1165 efflux pump genes. Susceptibilities of the selected strains to antibiotic and differences between susceptibilities of planktonic and biofilm-forming cell populations were determined. Quantitative real-time PCR (qPCR) analysis was performed using 16S rRNA gene as a H. pylori-specific primer, and two efflux pumps-specific primers, hp1165 and *** strains were resistant to amoxicillin, metronidazole, and erythromycin, except for one strain, but they were all susceptible to tetracycline. Minimum bactericidal concentrations of antibiotics in the biofilm-forming cells were significantly higher than those of planktonic cells. qPCR demonstrated that the expression of efflux pump genes was significantly higher in the biofilm-forming cells as compared to the planktonic *** present work demonstrated an association between H. pylori biofilm formation and decreased susceptibility to all the antibiotics tested. This decreased susceptibility to antibiotics was associated with enhanced functional activity of two efflux pumps: hp1165 and hefA.

关键词： Helicobacter pylori Biofilm Antibiotic resistance Efflux genes hp1165 hefA

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Post-infectious irritable bowel syndrome:Mechanistic insights into chronic disturbances following enteric infection

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World Journal of Gastroenterology 2014年第14期20卷 3976-3985页

作者： Jennifer K Beatty Amol Bhargava Andre G Buret department of biological sciences University of Calgary

Irritable bowel syndrome(IBS)is a commonly encountered chronic functional gastrointestinal(GI)*** 10%of IBS patients can trace the onset of their symptoms to a previous a bout of infectious *** appearance of new IBS symptoms following an infectious event is defined as ***,with the World Health Organization estimating between 2 and 4 billion cases annually,infectious diarrheal disease represents an incredible international healthcare ***,compounding evidence suggests many commonly encountered enteropathogens as unique triggers behind IBS symptom generation and underlying pathophysiological features.A growing body of work provides evidence supporting a role for pathogen-mediated modifications in the resident intestinal microbiota,epithelial barrier integrity,effector cell functions,and innate and adaptive immune features,all proposed physiological manifestations that can underlie GI abnormalities in *** pathogens must employ a vast array of machinery to evade host protective immune mechanisms,and illicit successful ***,the impact of infectious events on host physiology can be multidimensional in terms of anatomical location,functional scope,and *** review offers a unique discussion of the mechanisms employed by many commonly encountered enteric pathogens that cause acute disease,but may also lead to the establishment of chronic GI dysfunction compatible with IBS.

关键词： Post-infectious irritable bowel syndrome Infectious diarrhea Enteric pathogen Inflammatory disorders Immune alterations

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Soluble neuregulin-1(NRG1): a factor promoting peripheral nerve regeneration by affecting Schwann cell activity immediately after injury

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Neural Regeneration Research 2019年第8期14卷 1374-1375页

作者： Marwa El Soury Giovanna Gambarotta department of Clinical and biological sciences University of Torino

Neuregulin-1 (NRG1) is a well known growth factor playing contradictory roles in myelination depending on the existing isoform. Transmembrane NRG1 acts as a promyelinating factor, while the soluble isoform inhibits myelination. In this perspective, we would like to emphasize this conflicting role played by NRG1 isofbrms regarding their roles in myelination, remyelination and the entire process of peripheral nerve regeneration.

关键词： Soluble neuregulin-1 promoting peripheral injury

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Retinal ganglion cell neuroprotection induced by activation of alpha7 nicotinic acetylcholine receptors

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Neural Regeneration Research 2016年第6期11卷 918-919页

作者： Cindy L.Linn department of biological sciences Western Michigan University

Glaucoma is a group of degenerative retinal diseases that damage the eye’s optic nerve and can result in vision loss and *** is characterized by optic neuropathy,cupping of the optic disk.

关键词： nicotinic ganglion acetylcholine RGCs glaucoma optic neuropathy progressive initially periphery

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Situating and teaching 21st century zoology: revealing pattern in the form and function of animals

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Integrative Zoology 2009年第3期4卷 309-315页

作者： Anthony P.RUSSELL biological sciences University Department of of CalgaryCalgaryCanada

The current challenges(increasing levels of integration in the biological sciences)facing the teaching of zoology and the structure of the zoology curriculum are explored *** context is provided and a more focused scrutiny of the situation in North America is *** changing emphases in more broadly-based biological sciences programs in North America are outlined,and their influence on the role of zoology as part of fundamental biological training is *** longer term impact of such changes in emphasis on the teaching of zoology is discussed,and the central role that zoology can play in dealing with both science content and science education is *** upon a focal workshop on the future of the zoology curriculum in Canada,a perspective on the challenges facing curriculum evolution is *** curriculum redesign is called for to ensure that zoology provides a broad-scale integrative approach to the understanding of biodiversity in evolutionary,ecologi-cal and functional *** to,and drivers of change are identified and the need for collaborative ap-proaches to curricular evolution is emphasized.

关键词： curriculum education program undergraduate zoology.

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Seed dispersal in Hong Kong,China:past,present and possible futures

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Integrative Zoology 2011年第2期6卷 97-109页

作者： Richard T.CORLETT department of biological sciences National University of SingaporeSingapore

In the present article,published and unpublished information regarding seed dispersal in the degraded landscape of Hong Kong,China,is *** was available for 1681 native plant species,of which 1165 were assigned to probable seed dispersal *** accounted for one-third(34.4%)of all species evaluated,half(54.4%)of those from forests,and more than two-thirds(69.2%)of all trees and tall *** dispersal(25.9%)and dispersal by an unknown agent(30.7%)accounted for most of the rest,with the unknown species mostly small-seeded *** the frugivore fauna of the Hong Kong region has been truncated since the late Pleistocene,there are few clear examples of failed *** most striking is the absence of scatter-hoarding rodents from Hong Kong,despite the presence of forest trees that appear to require them for effective *** are also some large Lauraceae fruits that appear to be targeted at larger-gaped birds than currently *** endozoochorous species are dispersed by 3 small passerine birds(Pycnonotus jocosus,***,and Zosterops japonicus),with larger birds,fruit bats(Cynopterus sphinx,Rousettus leschenaulti),rhesus macaques(Macaca mulatta),civets(Paguma larvata,Viverricula indica),and muntjacs(Muntiacus muntjac)accounting for the *** low plant diversity in frugivore droppings,seed traps,and secondary vegetation suggests plant succession may be dispersal limited,although this has not been investigated *** underdispersed species is the simplest solution but,in the longer term,the(re)introduction of a scatter-hoarding rodent should be considered as well as that of other locally and regionally extinct frugivores.

关键词： China extinctions frugivory reintroduction seed dispersal

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Global Change Effects on Plant Chemical Defenses against Insect Herbivores

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Journal of Integrative Plant Biology 2008年第11期50卷 1339-1354页

作者： M.Gabriela Bidart-Bouzat Adebobola Imeh-Nathaniel department of biological sciences Bowling Green State University

This review focuses on individual effects of major global change factors, such as elevated CO2, O3, UV light and temperature, on plant secondary chemistry. These secondary metabolites are well-known for their role in plant defense against insect herbivory. Global change effects on secondary chemicals appear to be plant species-specifc and dependent on the chemical type. Even though plant chemical responses induced by these factors are highly variable, there seems to be some specificity in the response to different environmental stressors. For example, even though the production of phenolic compounds is enhanced by both elevated CO2 and UV light levels, the latter appears to primarily increase the concentrations of flavonoids. Likewise, specific phenolic metabolites seem to be induced by O3 but not by other factors, and an increase in volatile organic compounds has been particularly detected under elevated temperature. More information is needed regarding how global change factors influence inducibility of plant chemical defenses as well as how their indirect and direct effects impact insect performance and behavior, herbivory rates and pathogen attack. This knowledge is crucial to better understand how plants and their associated natural enemies will be affected in future changing environments.

关键词： elevated CO2 global climate change insect herbivory ozone plant chemical defenses plant-insect interactions plant secondary metabolites temperature tri-trophic interactions UV light.

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The endoplasmic reticulum: A dynamic and well-connected organelle

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Journal of Integrative Plant Biology 2015年第1期57卷 50-62页

作者： Chris Hawes Petra Kiviniemi Verena Kriechbaumer department of biological and Medical sciences Oxford Brookes University

The endoplasmic reticulum forms the first compart- ment in a series of organelles which comprise the secretory pathway, it takes the form of an extremely dynamic and pleomorphic membrane-bounded network of tubules and cisternae which have numerous different cellular functions. In this review, we discuss the nature of endoplasmic reticulum structure and dynamics, its relationship with closely associated organelles, and its possible function as a highway for the distribution and delivery of a diverse range of structures from metabolic complexes to viral particles.

关键词： Actin endomembranes Golgi microtubules myosin

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Invading from the garden？ A comparison of leaf herbivory for exotic and native plants in natural and ornamental settings

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Insect Science 2012年第6期19卷 677-682页

作者： Stephen F. Matter Jessica R.Brzyski Christopher J. Harrison Sara Hyams Clement Loo Jessica Loomis Hannah R. Lubbers Leeann Seastrum Trevor I. Stamper Adam M. Stein Richard Stokes Brandy S. Wilkerson department of biological sciences University of Cincinnati Cincinnati USA

The enemies release hypothesis proposes that exotic species can become in- vasive by escaping from predators and parasites in their novel environment. Agrawal et al. （Enemy release？ An experiment with congeneric plant pairs and diverse above- and below-ground enemies. Ecology, 86, 2979-2989） proposed that areas or times in which damage to introduced species is low provide opportunities for the invasion of native habitat. We tested whether ornamental settings may provide areas with low levels of herbivory for trees and shrubs, potentially facilitating invasion success. First, we compared levels of leaf herbivory among native and exotic species in ornamental and natural settings in Cincinnati, Ohio, United States. In the second study, we compared levels of herbivory for invasive and noninvasive exotic species between natural and ornamental settings. We found lower levels of leaf damage for exotic species than for native species; however, we found no differences in the amount of leaf damage suffered in ornamental or natural settings. Our results do not provide any evidence that ornamental settings afford additional release from herbivory for exotic plant species.

关键词： enemies release hypothesis forest herbivory host plant suburban urban

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