Antimicrobial activity of plant secondary metabolites: A review

The increasing incidence of microorganisms becoming resistant to antibiotics has continuously become a scientific community concern. Many scientists around the world are performing research on plants to be able to discover possible antimicrobial compounds. To date, many plant secondary compounds are known to have diverse biological activities. These may include antibacterial, antifungal and anticancer activities. In this regard, many scientists want to isolate, purify and identify plant secondary metabolites. The aim of this study is to provide recent insights on the different secondary metabolites class and the experimental evidences of antibacterial activities against many different pathogens. © 2014 Academic Journals Inc

Comparison and temperature study of lectin activities in Texas live oak (Quercus fusiformis) crude extracts

Lectins are proteins that contain at least one non-catalytic carbohydrate binding domain. In plants, these proteins are hypothesized to play a critical role in plant defense functions. The extant literature shows that lectins have diverse applications, including medicinal and therapeutic ones. This study examines the presence and the level of lectin activity in the Texas live oak (Quercus fusiformis Small), a plant native to and replete in the South Texas region. To detect and compare lectin activity among selected plant parts of Q. fusiformis, agglutination and protein assays were conducted. The influence of four factors on lectin activity was investigated. These factors are: plant part (leaf, stem and fruit), tree section (A, B and C), temperature (0, 50 and 100°C) and time duration (1, 2 and 3 h) at the different temperature levels. Analysis of variance (ANOVA) associated with a factorial experiment, mean comparisons by way of a Tukey\u27s test, trend analysis and regression analysis comprised the analytical strategy. Results indicated that lectin activity is present in each of the selected plant parts and varies significantly across these parts. ANOVA revealed that lectin activity is significantly linked to temperature level. Although relatively stable from 0 to 50°C, trend and regression analyses indicated significant linear and quadratic effects of temperature on lectin activity. These analyses indicated that maximum activity is predicted to occur at about 31°C. No interaction effect was detected between and among the four factors examined. © 2011 Academic Journals Inc

Collaboration paradox: Scientific productivity, the Internet, and problems of research in developing areas

(Ghana). The approach taken in the analysis was developed in a series of meetings held at the National Center for Ecological Analysis and Synthesis in Santa Barbara during this same period of time. This group of ‘Bobcows ’ was convened by Edward Hackett to examine the process of scientific collaboration in a variety of forms. We based the present work on similar analyses by Barry Bozeman, Sooho Lee, John Walsh and Nancy Mahoney. However, our gratitude is first and foremost to the outstanding teams of postgraduate interviewers from Loyola College of Social Sciences (Kerala), th

Evaluation of the antimicrobial activity of Zanthoxylum zanthoxyloides root bark extracts

The development of resistance to antibiotics by infectious agents has been a continuous challenge. Thus, in this study, the aim was to evaluate the antimicrobial activities of Zanthoxylum zanthoxyloides, a potential plant source for novel antibiotics. Toward this end, dried powdered samples of the root barks of Z. zanthoxyloides were extracted successively to obtain Crude Petroleum Ether (CPE), Defatted Ethanol Ether (DEE) and Defatted Ethanol Chloroform (DEC) extracts. The antimicrobial activities indicated by the size of the Zone of Inhibition (ZOI) of each extract at concentrations 5, 10, 15, 20 and 30 μg μL -1 were evaluated against Escherichia coli (E. coli), methicillin-susceptible Staphylococcus aureus (MSSA), Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VREF) using disc diffusion method. Two sets of Analysis of Variance (ANOVA) were performed. The first set comprised separate ANOVAs for each microorganism because the positive controls were different for each microorganism, although the negative control (DMSO) was the same for all. The second set was a single combined ANOVA with all microorganisms included with their positive controls excluded. The first set of analysis showed that DEE had significantly (p\u3c0.001) higher antimicrobial activity than DMSO, CPE, or DEC. No significant interaction between extract and concentration was detected. The second set indicated a significant (p\u3c0.01) interaction effect between extract and microorganism. Although no significant differences in ZOI were observed for microorganisms exposed to DMSO, CPE and DEC; one particular microorganism VREF was found to be the most susceptible to DEE. In addition, findings of this study show the potential of Z. zanthoxyloides as a source of broad-spectrum antimicrobial compounds. © 2012 Academic Journals Inc

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Hepatocyte Growth Factor, a Determinant of Airspace Homeostasis in the Murine Lung

<div><p>The alveolar compartment, the fundamental gas exchange unit in the lung, is critical for tissue oxygenation and viability. We explored hepatocyte growth factor (HGF), a pleiotrophic cytokine that promotes epithelial proliferation, morphogenesis, migration, and resistance to apoptosis, as a candidate mediator of alveolar formation and regeneration. Mice deficient in the expression of the HGF receptor <em>Met</em> in lung epithelial cells demonstrated impaired airspace formation marked by a reduction in alveolar epithelial cell abundance and survival, truncation of the pulmonary vascular bed, and enhanced oxidative stress. Administration of recombinant HGF to tight-skin mice, an established genetic emphysema model, attenuated airspace enlargement and reduced oxidative stress. Repair in the TSK/+ mouse was punctuated by enhanced akt and stat3 activation. HGF treatment of an alveolar epithelial cell line not only induced proliferation and scattering of the cells but also conferred protection against staurosporine-induced apoptosis, properties critical for alveolar septation. HGF promoted cell survival was attenuated by akt inhibition. Primary alveolar epithelial cells treated with HGF showed improved survival and enhanced antioxidant production. In conclusion, using both loss-of-function and gain-of-function maneuvers, we show that HGF signaling is necessary for alveolar homeostasis in the developing lung and that augmentation of HGF signaling can improve airspace morphology in murine emphysema. Our studies converge on prosurvival signaling and antioxidant protection as critical pathways in HGF–mediated airspace maintenance or repair. These findings support the exploration of HGF signaling enhancement for diseases of the airspace.</p> </div

Generation and characterization of mice deficient in <i>Met</i> expression in alveolar epithelial cells.

<p>A. Right panel-Representative immunohistochemical staining of c-Met in 2 week old mouse lungs. 40× magnification. N = 4–6 mice. Arrows denote expression in type II epithelial cells. Left panel-Representative immunohistochemical staining for HGF in 2 week old mouse lungs. 40× magnification. N = 4–6 mice. Scale bar (L): 25 µm, (R): 50 µm. Arrows denote exclusion of HGF from alveolar epithelial cells with apparent localization to the interstitium. B. Representative fluorescent immunohistochemistry of phosphorylated c-Met in mice deficient in <i>Met</i> and bitransgenic controls. Green-p-Met. 40× magnification. N = 4–6 mice. Scale bar: 25 µm. C. Quantitative immunohistochemistry of p-met expression in the airspace of <i>Met</i>-deleted mice and controls. D. Representative histology of mice deficient in airspace <i>Met</i> expression and controls at two weeks of age. Note patchy airspace enlargement in the targeted mice. Scale bar: 100 µm. E. Airspace dimension by morphometry in <i>Met</i>-deficient mice and controls at 2 and 3 weeks of age. F. Quantitation of SPC+ cells in the airspace by SPC immunohistochemistry in <i>Met</i>-deficient mice compared with control bitransgenic mice. *p<0.05. G. Representative thrombomodulin immunohistochemical staining of the microvascular bed in the lung parenchyma of Met deficient mice compared with controls. Inset shows reduced staining in the alveolar epithelial walls. 40× magnification, inset 100×. N = 5–7 mice per genotype. H. Quantitative immunohistochemistry of thromobomodulin staining of <i>Met</i>-deficient mice and controls. **p<0.01.</p

HGF treatment of MLE12 induces prosurvival signaling that protects against alveolar cell death.

<p>A. Representative immunoblots of phosphoproteins in mice treated with HGF for 5 min (pERK and pJNK) or 15 min (pAKT) showing dose response. B. Cleaved caspase 3 immunoblotting in MLE12 cells treated with staurosporine with or without HGF or wortmannin. All experiments performed in triplicate.</p

HGF treatment improves airspace caliber in TSK/+ mice.

<p>A. Serum HGF levels in mice treated with HGF infusion pumps at 50 µg/d. **p<.001 B. Phospho-Met immunofluorescent staining in lungs of mice treated with HGF infusion compared with PBS carrier infusion. Arrow in inset denotes phosphorylated c-Met (p-Met, green) in alveolar epithelial cells of HGF treated mice. Scale bar: 50 µm. C. Histology of TSK/+ lung treated with HGF compared with untreated controls. 20× magnification. Scale bar 100 µm. D. Morphometric assessment of airspace dimension in mice treated with HGF for 2 weeks compared with wild-type mice and untreated controls. Lo HGF-50 µg/d. Hi HGF-100 µg/d. E. Representative staining for oxidative stress marker nitrotyrosine in lungs of TSK/+ mice treated with HGF and controls. Arrow denotes staining in alveolar epithelial cells. 40× magnification. Scale bar 50 µm. F. Quantitative immunohistochemistry of nitrotyrosine staining in TSK/+ lungs treated with saline or HGF by infusion pump compared to wild-type controls. G. Representative immunoblotting of normalized phosphomediator levels (akt and stat3) in two TSK/+ mice treated with HGF compared with saline treated mice. N = 4–8 mice per group and treatment.</p