scholarly journals Expression of a Novel Small Antimicrobial Protein from the Seeds of Motherwort (Leonurus japonicus) Confers Disease Resistance in Tobacco

2006 ◽  
Vol 73 (3) ◽  
pp. 939-946 ◽  
Author(s):  
Xingyong Yang ◽  
Yuehua Xiao ◽  
Xiaowen Wang ◽  
Yan Pei
Keyword(s):  
Storage Proteins ◽  
Bacterial Pathogen ◽  
Hyphal Growth ◽  
Antimicrobial Activities ◽  
In Vitro Assays ◽  
Antimicrobial Protein ◽  
Heat Stable ◽  
Antimicrobial Materials ◽  
Rapid Amplification

ABSTRACT Medicinal plants are valuable resources of natural antimicrobial materials. A novel small protein with antimicrobial activities, designated LJAMP1, was purified from the seeds of a medicinal herb, motherwort (Leonurus japonicus Houtt). LJAMP1 is a heat-stable protein with a molecular mass of 7.8 kDa and a determined isoelectric point of 8.2. In vitro assays showed that LJAMP1 inhibits the growth of an array of fungi and bacteria. The hyphal growth inhibition by LJAMP1 was more evident against hyphomycete fungi, such as Alternaria alternata, Cercospora personata, and Aspergillus niger. The N-terminal amino acid sequence of LJAMP1 was determined, and its coding gene was consequently cloned by the rapid amplification of cDNA ends. The gene LJAMP1 has no intron and encodes a polypeptide of 95 amino acids, in which the first 27 residues was deduced as a signal peptide. The mature LJAMP1 shows relatively low identity to plant napin-like storage proteins. Northern blot assays revealed that LJAMP1 is expressed preferentially in seeds. Bioassays in transgenic tobacco demonstrated that that overexpression of LJAMP1 significantly enhanced the resistance of tobacco against not only the fungal pathogen A. alternata but also the bacterial pathogen Ralstonia solanacearum, while no visible alteration in plant growth and development was observed.

Regulation of cell growth by vitreous humour

1985 ◽  
Vol 76 (1) ◽  
pp. 53-65
Author(s):  
G.A. Lutty ◽  
R.J. Mello ◽  
C. Chandler ◽  
C. Fait ◽  
A. Bennett ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Pigment Epithelium ◽  
Chorioallantoic Membrane ◽  
Growth Inhibitor ◽  
Muscle Cells ◽  
In Vitro Assays ◽  
Heat Stable ◽  
Heat Labile

Extracts of normal vitreous have been found to inhibit angiogenesis in two animal models: tumour-induced neovascularization in the rabbit corneal micropocket and retinal extract-induced angiogenesis in the chick chorioallantoic membrane assay. Using in vitro assays, we have found recently that an extract of bovine vitreous, free of hyaluronic acid, inhibits proliferation of cells in the aortic wall, i.e. endothelium and smooth muscle cells, as well as capillary and corneal endothelium. The inhibition is dose-dependent, as determined by either cell count or [3H]thymidine incorporation, and not due to cytotoxicity, as demonstrated with a double-label thymidine assay. The inhibitor is trypsin-sensitive and heat-stable (95 degrees C for 10 min). Conversely, proliferation of pericytes, lens epithelium and fibroblasts (dermal and corneal) was stimulated by the vitreous extract. This mitogenic activity was heat-labile. Growth of pigment epithelium and several tumour cell lines was unaffected. The data demonstrate that normal vitreous contains a heat-stable growth inhibitor specific for endothelium and smooth muscle cells, and a non-specific heat-labile mitogen. The paradoxical effect of this antiangiogenic factor on arterial and capillary contractile cells, smooth muscle and pericytes, suggests a basic difference in the regulation of the two vasculatures. The results suggest that a substance in normal vitreous may be important in controlling neovascularization that results from diabetic and other retinopathies, and could be useful for inhibiting tumour-induced angiogenesis.

scholarly journals Transposon Mutagenesis Screen of Klebsiella pneumoniae Identifies Multiple Genes Important for Resisting Antimicrobial Activities of Neutrophils in Mice

2020 ◽  
Vol 88 (4) ◽  
Author(s):  
Michelle K. Paczosa ◽  
Rebecca J. Silver ◽  
Anne L. McCabe ◽  
Albert K. Tai ◽  
Colin H. McLeish ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Bacterial Pathogen ◽  
Reactive Oxygen ◽  
Antimicrobial Activities ◽  
Virulence Determinants ◽  
Nitrogen Species ◽  
Content Type ◽  
Transposon Insertion ◽  
Tract Infections

ABSTRACT Klebsiella pneumoniae is a Gram-negative bacterial pathogen that causes a range of infections, including pneumonias, urinary tract infections, and septicemia, in otherwise healthy and immunocompromised patients. K. pneumoniae has become an increasing concern due to the rise and spread of antibiotic-resistant and hypervirulent strains. However, its virulence determinants remain understudied. To identify novel K. pneumoniae virulence factors needed to cause pneumonia, a high-throughput screen was performed with an arrayed library of over 13,000 K. pneumoniae transposon insertion mutants in the lungs of wild-type (WT) and neutropenic mice using transposon sequencing (Tn-seq). Insertions in 166 genes resulted in K. pneumoniae mutants that were significantly less fit in the lungs of WT mice than in those of neutropenic mice. Of these, mutants with insertions in 51 genes still had significant defects in neutropenic mice, while mutants with insertions in 52 genes recovered significantly. In vitro screens using a minilibrary of K. pneumoniae transposon mutants identified putative functions for a subset of these genes, including in capsule content and resistance to reactive oxygen and nitrogen species. Lung infections in mice confirmed roles in K. pneumoniae virulence for the ΔdedA, ΔdsbC, ΔgntR, Δwzm-wzt, ΔyaaA, and ΔycgE mutants, all of which were defective in either capsule content or growth in reactive oxygen or nitrogen species. The fitness of the ΔdedA, ΔdsbC, ΔgntR, ΔyaaA, and ΔycgE mutants was higher in neutropenic mouse lungs, indicating that these genes encode proteins that protect K. pneumoniae against neutrophil-related effector functions.

Phytochemical and Biological Activities of five Turanecio Hamzaoglu (Asteraceae) Species from Turkey

2017 ◽  
Vol 13 (1) ◽  
pp. 49-55
Author(s):  
Sevil Albayrak ◽  
Ahmet Aksoy ◽  
Abit Yasar ◽  
Lutfiye Yurtseven ◽  
Umit Budak
Keyword(s):  
Therapeutic Potential ◽  
Antioxidant Activities ◽  
Biological Activities ◽  
Natural Antioxidants ◽  
Antibacterial Activities ◽  
Antimicrobial Activities ◽  
In Vitro Assays ◽  
Methanolic Extracts ◽  
Promising Source

Objectives: In vitro biological activities of methanolic extracts of five Turanecio species have been studied. Materials and Methods: The phenolic compositions of the extracts were evaluated by the Folin- Ciocalteu assay and by HPLC analysis. Antioxidant activities were determined with two in vitro assays namely, DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging assay and phosphomolybdenum assay. The antimicrobial activities of the extracts were evaluated against 13 microorganisms. Results: T. hypochionaeus var. hypochionaeus was showed the highest DPPH inhibition with 88.84% at 100 μg·mL-1. All of the extracts were exerted high total antioxidant activities 128.00- 243.13 mg AAE g-1) and seem to be a promising source of natural antioxidants. The phenolic contents in the extracts varied from 26.17 to 60.99 mg·g-1 as gallic acid equivalent. Chlorogenic acid, caffeic acid and p- coumaric acid were the predominant constituents. The methanolic extracts revealed promising antibacterial activities against most bacteria. No activity was recorded against yeasts tested. Conclusion: The polyphenolic constituents appear to be responsible, at least in part, for the extract’s activities. The present study confirms that tested Turanecio species contains significant source of phenolics have antioxidant and antimicrobial activities and may have therapeutic potential.

scholarly journals Antagonism of Trichoderma harzianum ETS 323 on Botrytis cinerea Mycelium in Culture Conditions

2012 ◽  
Vol 102 (11) ◽  
pp. 1054-1063 ◽  
Author(s):  
Chi-Hua Cheng ◽  
Chia-Ann Yang ◽  
Kou-Cheng Peng
Keyword(s):  
Amino Acid ◽  
Botrytis Cinerea ◽  
Trichoderma Harzianum ◽  
Hyphal Growth ◽  
Extracellular Proteins ◽  
In Vitro Assays ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Trichoderma Spp

Previous studies have shown that the extracellular proteins of Trichoderma harzianum ETS 323 grown in the presence of deactivated Botrytis cinerea in culture include a putative l-amino acid oxidase and have suggested the involvement of this enzyme in the antagonistic mechanism. Here, we hypothesized that the mycoparasitic process of Trichoderma spp. against B. cinerea involves two steps; that is, an initial hyphal coiling stage and a subsequent hyphal coiling stage, with different coiling rates. The two-step antagonism of T. harzianum ETS 323 against B. cinerea during the mycoparasitic process in culture was evaluated using a biexponential equation. In addition, an l-amino acid oxidase (Th-l-AAO) was identified from T. harzianum ETS 323. The secretion of Th-l-AAO was increased when T. harzianum ETS 323 was grown with deactivated hyphae of B. cinerea. Moreover, in vitro assays indicated that Th-l-AAO effectively inhibited B. cinerea hyphal growth, caused cytosolic vacuolization in the hyphae, and led to hyphal lysis. Th-l-AAO also showed disease control against the development of B. cinerea on postharvest apple fruit and tobacco leaves. Furthermore, an apoptosis-like response, including the generation of reactive oxygen species, was observed in B. cinerea after treatment with Th-l-AAO, suggesting that Th-l-AAO triggers programmed cell death in B. cinerea. This may be associated with the two-step antagonism of T. harzianum ETS 323 against B. cinerea.

scholarly journals CesH Represses Cereulide Synthesis as an Alpha/Beta Fold Hydrolase in Bacillus cereus

Toxins ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 231 ◽  
Author(s):  
Shen Tian ◽  
Hairong Xiong ◽  
Peiling Geng ◽  
Zhiming Yuan ◽  
Xiaomin Hu
Keyword(s):  
Bacillus Cereus ◽  
Bond Cleavage ◽  
Catalytic Triad ◽  
In Vitro Assays ◽  
Heat Stable ◽  
In The Wild ◽  
Alpha Beta ◽  
Toxin Degradation

Cereulide is notorious as a heat-stable emetic toxin produced by Bacillus cereus and glucose is supposed to be an ingredient supporting its formation. This study showed that glucose addition benefited on cell growth and the early transcription of genes involved in substrate accumulation and toxin synthesis, but it played a negative role in the final production of cereulide. Meanwhile, a lasting enhancement of cesH transcription was observed with the addition of glucose. Moreover, the cereulide production in ΔcesH was obviously higher than that in the wild type. This indicates that CesH has a repression effect on cereulide production. Bioinformatics analysis revealed that CesH was an alpha/beta hydrolase that probably associated with the cell membrane, which was verified by subcellular localization. The esterase activity against para-nitrophenyl acetate (PNPC2) of the recombinant CesH was confirmed. Although no sign of ester bond cleavage in cereulide or valinomycin was demonstrated in in vitro assays, CesH could reverse the cereulide analogue sensitivity of Bacillus subtilis in vivo, by which toxin degradation was facilitated. Moreover, site directed mutations identified that the conserved catalytic triad of CesH might consist of Serine 86, Glutamate 199, and Histidine 227. These results help us to understand the regulation of cereulide production and provide clues for developing control measurements.

scholarly journals Acinetobacter baumannii Coordinates Urea Metabolism with Metal Import To Resist Host-Mediated Metal Limitation

mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
Lillian J. Juttukonda ◽  
Walter J. Chazin ◽  
Eric P. Skaar
Keyword(s):  
Acinetobacter Baumannii ◽  
Pathogenic Bacteria ◽  
Bloodstream Infections ◽  
Antimicrobial Activities ◽  
Innate Immune ◽  
Antimicrobial Protein ◽  
Carboxylase Activity ◽  
Metal Sequestration

ABSTRACT During infection, bacterial pathogens must adapt to a nutrient metal-limited environment that is imposed by the host. The innate immune protein calprotectin inhibits bacterial growth in vitro by chelating the divalent metal ions zinc (Zn 2+ , Zn) and manganese (Mn 2+ , Mn), but pathogenic bacteria are able to cause disease in the presence of this antimicrobial protein in vivo. One such pathogen is Acinetobacter baumannii , a Gram-negative bacterium that causes pneumonia and bloodstream infections that can be complicated by resistance to multiple antibiotics. A. baumannii inhibition by calprotectin is dependent on calprotectin Mn binding, but the mechanisms employed by A. baumannii to overcome Mn limitation have not been identified. This work demonstrates that A. baumannii coordinates transcription of an NRAMP family Mn transporter and a urea carboxylase to resist the antimicrobial activities of calprotectin. This NRAMP family transporter facilitates Mn accumulation and growth of A. baumannii in the presence of calprotectin. A. baumannii is found to utilize urea as a sole nitrogen source, and urea utilization requires the urea carboxylase encoded in an operon with the NRAMP family transporter. Moreover, urea carboxylase activity is essential for calprotectin resistance in A. baumannii . Finally, evidence is provided that this system combats calprotectin in vivo , as deletion of the transporter impairs A. baumannii fitness in a mouse model of pneumonia, and this fitness defect is modulated by the presence of calprotectin. These findings reveal that A. baumannii has evolved mechanisms to subvert host-mediated metal sequestration and they uncover a connection between metal starvation and metabolic stress. IMPORTANCE Acinetobacter baumannii is a bacterium that causes bloodstream, wound, urinary tract, and pneumonia infections, with a high disease burden in intensive care units. Treatment of A. baumannii infection is complicated by resistance to most antibiotics in use today, and resistance to last-resort therapies has become commonplace. New treatments for A. baumannii infection are desperately needed, but our current understanding of the bacterial factors required to cause infection is limited. We previously found that the abundant innate immune protein calprotectin inhibits the growth of A. baumannii by withholding essential metals . Despite this, A. baumannii is still able to infect wild-type mice, which produce calprotectin during infection. Here, we identify factors employed by A. baumannii during infection to overcome calprotectin-mediated metal sequestration. Moreover, we expose a connection between metal starvation and metabolism that may be a “chink in the armor” of A. baumannii and lead to new treatment options.

scholarly journals The Tobacco Trichome Exudate Z-abienol and Its Relationship With Plant Resistance to Phytophthora nicotianae

Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1214-1221 ◽  
Author(s):  
William T. Steede ◽  
Justin M. Ma ◽  
David P. Eickholt ◽  
Katherine E. Drake-Stowe ◽  
Sheri P. Kernodle ◽  
...  
Keyword(s):  
Close Association ◽  
Hyphal Growth ◽  
Field Resistance ◽  
Phytophthora Nicotianae ◽  
In Vitro Assays ◽  
Black Shank ◽  
Plant Parts ◽  
Tobacco Cultivar ◽  
High Level

In previous research, we discovered a favorable quantitative trait locus (QTL) in cigar tobacco cultivar ‘Beinhart 1000’ designated as Phn15.1, which provides a high level of partial resistance to the black shank disease caused by Phytophthora nicotianae. A very close genetic association was also found between Phn15.1 and the ability to biosynthesize Z-abienol, a labdanoid diterpene exuded by the trichomes onto above-ground plant parts, and that imparts flavor and aroma characteristics to Oriental and some cigar tobacco types. Because accumulation of Z-abienol is considered to be undesirable for cultivars of other tobacco types, we herein describe a series of experiments to gain insight on whether this close association is due to genetic linkage or pleiotropy. First, in an in vitro bioassay, we observed Z-abienol and related diterpenes to inhibit hyphal growth of P. nicotianae at concentrations between 0.01 and 100 ppm. Secondly, we field-tested transgenic versions of Beinhart 1000 carrying RNAi constructs for downregulating NtCPS2 or NtABS, two genes involved in the biosynthesis of Z-abienol. Thirdly, we also field tested a recombinant inbred line population segregating for a truncation mutation in NtCPS2 leading to an interrupted Z-abienol pathway. We observed no correlation between field resistance to P. nicotianae and the ability to accumulate Z-abienol in either the transgenic materials or the mapping population. Results suggest that, although Z-abienol may affect P. nicotianae when applied at high concentrations in in vitro assays, the compound has little effect on black shank disease development under natural field conditions. Thus, it should be possible to disassociate Phn15.1-mediated black shank resistance identified in cigar tobacco cultivar Beinhart 1000 from the ability to accumulate Z-abienol, an undesirable secondary metabolite for burley and flue-cured tobacco cultivars.

scholarly journals Chemical Synthesis and Hemi-Synthesis of Novel Benzimidazole Derivatives Using Microwave-Assisted Process: Chemical Characterization, Bioactivities and Molecular Docking

2020 ◽  
Vol 3 (1) ◽  
pp. 71
Author(s):  
Asmaâ Sameut ◽  
Sarah Yasmine Zanndouche ◽  
Chaimaa Boumaza ◽  
Chaima Dikes ◽  
Borhane Eddine Cherif Ziani
Keyword(s):  
Molecular Docking ◽  
Reducing Power ◽  
Antimicrobial Activities ◽  
In Vitro Assays ◽  
Synthesis Process ◽  
Benzimidazole Derivatives ◽  
Thiobarbituric Acid Reactive Substance ◽  
E Coli ◽  
Wide Range

Benzimidazole derivatives represent a class of heterocyclic compounds that exhibit a wide range of pharmaceutical properties. The present study aimed to investigate the in-vitro antioxidant and antimicrobial activities of newly synthesized benzimidazole derivatives. Compound 1b (2-(1H-1,3-benzodiazol-2-yl) phenol) was synthesized by reacting o-phenylenediamine (OPA) with chemical salicylaldehyde, while compounds 2b (2-(2-[(1E)-2-phenylethenyl]-1H-1,3-benzodiazole) and 3b (2-[(1E)-2,6-dimethylhepta-1,5-dien-1-yl]-1H-1,3-benzodiazole) were obtained through a hemi-synthesis process of, respectively, the cinnamon (cinnamaldehyde, 90.54%) and lemongrass (cis-citral, 43.9%) essential oils previously characterized by GC/MS. Compounds 4b (2-phenyl-1H-benzimidazole) and 5b (5-(1H-benzimidazol-2-yl)benzene-1,2,3-triol) were synthesized with a click chemistry method by reacting the OPA with benzoic acid and gallic acid directly in ethanol under microwave irradiation (MW) at 400 MHz. The structure/purity of the synthesized compounds was clarified by spectroscopy, ATR-FTIR and NMR 1H. Compounds 1b–5b were screened for their antioxidant activity by using four complementary in-vitro assays: DPPH scavenging activity, ferric ion reducing power, β-carotene bleaching inhibition, and Thiobarbituric Acid Reactive Substance Assay (TBARS) formation inhibition. All the tested compounds showed antioxidant potential, with varying performance. Antimicrobial activity was investigated against American Type Culture Collection (ATCC) strains (three Gram- bacteria: Escherichia coli, Salmonella typhi, and Pseudomonas aeruginosa; one Gram+ bacteria: Staphylococcus aureus, and one yeast strain: Candida albicans) through the determination of the Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) by using the microdilution method and rapid colorimetric test of p-iodonitrotetrazolium chloride (INT). Compound 5b exhibited the highest potential, especially against S. aureus (MIC = 0.156 mg·mL−1) followed by S. typhi and C. albicans (MIC = 0.3125 mg·mL−1) and then by E. coli and P. aeruginosa. Compound 1b also showed great potential against S. aureus and C. albicans (MIC ˂ 0.3125 mg·mL−1), followed by E. coli and S. typhi (MIC = 0.3125 mg·mL−1) and P. aeruginosa (MIC = 0.625 mg·mL−1). Further molecular docking was conducted using AutoDock Vina 1.1.2 software on S. aureus thymidylate kinase (TMK) protein to highlight the structure–activity relationship of the potent molecules.

scholarly journals Polyphenolic Content, Antioxidant and Antimicrobial Activities of Vernonia mespilifolia Less. Used in Folk Medicine in the Eastern Cape Province, South Africa

2018 ◽  
Vol 23 ◽  
pp. 2515690X1877399 ◽  
Author(s):  
Jeremiah Oshiomame Unuofin ◽  
Gloria Aderonke Otunola ◽  
Anthony Jide Afolayan
Keyword(s):  
Antioxidant Activities ◽  
Folk Medicine ◽  
Antimicrobial Properties ◽  
Antimicrobial Activities ◽  
In Vitro Assays ◽  
Eastern Cape ◽  
Polyphenolic Content ◽  
Ethanol Extracts ◽  
Bacteria And Fungi

Vernonia mespilifolia Less. is a shrub of the Asteraceae family used in the South African traditional medicine system for the management of weight loss, hypertension, and heartwater disease. There is a need for scientific evaluation to validate its ethnomedicinal usage. In vitro assays were conducted to evaluate the polyphenolic content, antioxidant and antimicrobial properties of different solvent extracts (acetone, aqueous, and ethanol) of the whole plant of Vernonia mespilifolia spectrophotometric and agar dilution techniques, respectively. The result revealed varying amounts of polyphenolics in the different solvent extracts corresponding to the antioxidant activities. Also, only the acetone and ethanol extracts inhibited the growth of the selected bacteria and fungi. These findings reveal that the extracts have strong bioactive compounds and hence support its ethnomedicinal application.

scholarly journals Response of Ants to a Deterrent Factor(s) Produced by the Symbiotic Bacteria of Entomopathogenic Nematodes

2002 ◽  
Vol 68 (12) ◽  
pp. 6202-6209 ◽  
Author(s):  
Xinsheng Zhou ◽  
Harry K. Kaya ◽  
Kurt Heungens ◽  
Heidi Goodrich-Blair
Keyword(s):  
Entomopathogenic Nematodes ◽  
Sucrose Concentration ◽  
In Vitro Assays ◽  
Symbiotic Bacteria ◽  
Xenorhabdus Nematophila ◽  
Bacterial Cultures ◽  
Heat Stable ◽  
Species Being

ABSTRACT The production of an ant-deterrent factor(s) (ADF) by Xenorhabdus nematophila and Photorhabdus luminescens, the symbiotic bacteria of the nematodes Steinernema carpocapsae and Heterorhabditis bacteriophora, respectively, was examined. In addition to an in vivo assay in which bacteria were tested for their ability to produce ADF within insect cadavers (M.E. Baur, H. K. Kaya, and D. R. Strong, Biol. Control 12:231-236, 1998), an in vitro microtiter dish assay was developed to monitor ADF activity produced by bacteria grown in cultures. Using these methods, we show that ADF activity is present in the supernatants of bacterial cultures, is filterable, heat stable, and acid sensitive, and passes through a 10-kDa-pore-size membrane. Thus, ADF appears to be comprised of a small, extracellular, and possibly nonproteinaceous compound(s). The amount of ADF repellency detected depends on the ant species being tested, the sucrose concentration (in vitro assays), and the strain, form, and age of the ADF-producing bacteria. These findings demonstrate that the symbiotic bacteria of some species of entomopathogenic nematodes produce a compound(s) that deters scavengers such as ants and thus could protect nematodes from being eaten during reproduction within insect cadavers.

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