scholarly journals A Novel Antibacterial Component and the Mechanisms of an Amaranthus tricolor Leaf Ethyl Acetate Extract against Acidovorax avenae subsp. citrulli

2021 ◽  
Vol 23 (1) ◽  
pp. 312
Author(s):  
Ya Zhang ◽  
Ke Gao ◽  
Chong Wang ◽  
Shuangqing Liu

The aim of the present investigation was to determine the active ingredients in Amaranthus tricolor L. leaves and develop a biological pesticide. Organic solvent extraction, column chromatography, liquid chromatography, ODS-C18 reverse elution, Sephadex LH-20 gel filtration, H spectrum, and C spectrum were used to isolate the pure product for an assessment of the agricultural activity and bacteriostatic mechanisms. The results showed that the activity of the crude extract following carbon powder filtration was 1.63-fold that of the non-filtered extract. Further isolation was performed to obtain two pure products, namely, hydroxybenzoic acid (HBA) and benzo[b]furan-2-carboxaldehyde (BFC), and their molecular formulas and molecular weights were C7H6O3 and 138.12, and C9H6O2 and 146.12, respectively. Our study is the first to determine that HBA has bacteriostatic activity (MIC 125 μg/mL) and is also the first to isolate BFC from A. tricolor. The ultrastructure observation results showed that HBA caused the bacteria to become shriveled, distorted, and deformed, as well as exhibit uneven surfaces. After HBA treatment, 70 differentially expressed metabolites were detected in the bacteria, of which 9 were downregulated and 61 were upregulated. The differentially expressed metabolites were mainly strigolactones, organic acids and derivatives, fatty acids, benzene and substituted benzene derivatives, amino acids and associated metabolites, and alcohols and amines. Among all of the downregulated differentially expressed metabolites, MEDP1280 was the most critical, as it participates in many physiological and biochemical processes. The enrichment analysis showed that the differentially expressed metabolites mainly participate in tyrosine metabolism, biosynthesis of amino acids, cysteine and methionine metabolism, and arginine and proline metabolism. Additionally, HBA was found to disrupt cell membrane permeability and integrity, causing the leakage of substances and apoptosis. The physiological and biochemical test results showed that HBA could increase the pyruvate levels in bacteria but could decrease the activities of respiratory enzymes (malate dehydrogenase (MDH) and NADH oxidase) and antioxidant enzymes (superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX)). Inverse molecular docking was used to study the binding between HBA and respiratory and antioxidant enzymes. The results showed that HBA could bind to MDH, NADH oxidase, SOD, and GSH-PX, suggesting that these enzymes may be the effector targets of HBA. Conclusion: The optimal active ingredient in A. tricolor that can inhibit Acidovorax avenae subsp. citrulli was identified as HBA. HBA mainly disrupts the cell membrane, damages the metabolic system, and inhibits respiration and antioxidant enzyme activity to control bacterial growth. These results provide a reference for the further development of biological pesticides.

Author(s):  
M. Ashraf ◽  
L. Landa ◽  
L. Nimmo ◽  
C. M. Bloor

Following coronary artery occlusion, the myocardial cells lose intracellular enzymes that appear in the serum 3 hrs later. By this time the cells in the ischemic zone have already undergone irreversible changes, and the cell membrane permeability is variably altered in the ischemic cells. At certain stages or intervals the cell membrane changes, allowing release of cytoplasmic enzymes. To correlate the changes in cell membrane permeability with the enzyme release, we used colloidal lanthanum (La+++) as a histological permeability marker in the isolated perfused hearts. The hearts removed from sprague-Dawley rats were perfused with standard Krebs-Henseleit medium gassed with 95% O2 + 5% CO2. The hypoxic medium contained mannitol instead of dextrose and was bubbled with 95% N2 + 5% CO2. The final osmolarity of the medium was 295 M osmol, pH 7. 4.


Author(s):  
Shen Jean Lim ◽  
Brenton Davis ◽  
Danielle Gill ◽  
John Swetenburg ◽  
Laurie C Anderson ◽  
...  

Abstract Lucinid bivalves harbor environmentally acquired, chemosynthetic, gammaproteobacterial gill endosymbionts. Lucinid gill microbiomes, which may contain other gammaproteobacterial and/or spirochete taxa, remain under-sampled. To understand inter-host variability of the lucinid gill microbiome, specifically in the bacterial communities, we analyzed the microbiome content of Stewartia floridana collected from Florida. Sampled gills contained a monospecific gammaproteobacterial endosymbiont expressing lithoautotrophic, mixotrophic, diazotrophic, and C1 compound oxidation-related functions previously characterized in similar lucinid species. Another low-abundance Spirochaeta-like species in ∼72% of the sampled gills was most closely related to Spirochaeta-like species in another lucinid Phacoides pectinatus and formed a clade with known marine Spirochaeta symbionts. The spirochete expressed genes were involved in heterotrophy and the transport of sugars, amino acids, peptides, and other substrates. Few muscular and neurofilament genes from the host and none from the gammaproteobacterial and spirochete symbionts were differentially expressed among quadrats predominantly covered with seagrass species or 80% bare sand. Our results suggest that spirochetes are facultatively associated with S. floridana, with potential scavenging and nutrient cycling roles. Expressed stress- and defense-related functions in the host and symbionts also suggest species-species communications, which highlight the need for further study of the interactions among lucinid hosts, their microbiomes, and their environment.


2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Chunlan Shan ◽  
Shushu Miao ◽  
Chaoying Liu ◽  
Bo Zhang ◽  
Weiwei Zhao ◽  
...  

Abstract Background Pyroptosis plays a pivotal role in the pathogenesis of many inflammatory diseases. The molecular mechanism by which pyroptosis is induced in macrophages following infection with pathogenic E. coli high pathogenicity island (HPI) will be evaluated in our study. Results After infection with the HPI+/HPI− strains and LPS, decreased macrophage cell membrane permeability and integrity were demonstrated with propidium iodide (PI) staining and the lactate dehydrogenase (LDH) assay. HPI+/HPI−-infection was accompanied by upregulated expression levels of NLRP3, ASC, caspase-1, IL-1β, IL-18 and GSDMD, with significantly higher levels detected in the HPI+ group compared to those in the HPI− group (P < 0.01 or P < 0.05). HPI+ strain is more pathogenic than HPI− strain. Conclusion Our findings indicate that pathogenic E. coli HPI infection of Saba pigs causes pyroptosis of macrophages characterized by upregulated expression of pyroptosis key factors in the NLRP3/ASC/caspase-1 signaling pathway, direct cell membrane pore formation, and secretion of the inflammatory factor IL-1β and IL-18 downstream of NLRP3 and caspase-1 activation to enhance the inflammatory response.


2015 ◽  
Vol 25 (17) ◽  
pp. 3610-3615 ◽  
Author(s):  
Junsuke Hayashi ◽  
Tomoko Hamada ◽  
Ikumi Sasaki ◽  
Osamu Nakagawa ◽  
Shun-ichi Wada ◽  
...  

1974 ◽  
Vol 64 (6) ◽  
pp. 706-729 ◽  
Author(s):  
W. R. Redwood ◽  
E. Rall ◽  
W. Perl

The permeability coefficients of dog red cell membrane to tritiated water and to a series of[14C]amides have been deduced from bulk diffusion measurements through a "tissue" composed of packed red cells. Red cells were packed by centrifugation inside polyethylene tubing. The red cell column was pulsed at one end with radiolabeled solute and diffusion was allowed to proceed for several hours. The distribution of radioactivity along the red cell column was measured by sequential slicing and counting, and the diffusion coefficient was determined by a simple plotting technique, assuming a one-dimensional diffusional model. In order to derive the red cell membrane permeability coefficient from the bulk diffusion coefficient, the red cells were assumed to be packed in a regular manner approximating closely spaced parallelopipeds. The local steady-state diffusional flux was idealized as a one-dimensional intracellular pathway in parallel with a one-dimensional extracellular pathway with solute exchange occurring within the series pathway and between the pathways. The diffusion coefficients in the intracellular and extracellular pathways were estimated from bulk diffusion measurements through concentrated hemoglobin solutions and plasma, respectively; while the volume of the extracellular pathway was determined using radiolabeled sucrose. The membrane permeability coefficients were in satisfactory agreement with the data of Sha'afi, R. I., C. M. Gary-Bobo, and A. K. Solomon (1971. J. Gen. Physiol. 58:238) obtained by a rapid-reaction technique. The method is simple and particularly well suited for rapidly permeating solutes.


Lab on a Chip ◽  
2021 ◽  
Author(s):  
Hsiu-Yang Tseng ◽  
Chiu-Jen Chen ◽  
Zong-Lin Wu ◽  
Yong-Ming Ye ◽  
Guo-Zhen Huang

Cell-membrane permeability to water (Lp) and cryoprotective agents (Ps) of a cell type is a crucial cellular information for achieving optimal cryopreservation in the biobanking industry. In this work, a...


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 116-116
Author(s):  
Cedrick N N Shili ◽  
Mohammad Habibi ◽  
Parniyan Goodarzi ◽  
Frank Kiyimba ◽  
Steve Hartsen ◽  
...  

Abstract Feeding pigs with very low-protein (VLP) and low-phosphorous (P) diets may be useful for decreasing the nutrients excretion to the environment; however, this practice negatively impacts the animals’ growth performance. A beneficial effect of corn-expressed phytase (CEP) on growth performance of pigs fed with VLP diets was shown by our group recently. Little is known whether this improvement is related with alterations in profile of blood proteins and amino acids (AA). The objective of this study was to investigate whether supplementation of VLP, low-calcium (Ca) and low-P diets with a CEP can influence the serum AA and proteomics profiles in pigs. Forty-eight weaned barrows were subjected into one of the following groups (n = 8/group) for 4 weeks: positive control (PC), negative control-reduced protein (NC), NC+low-dose CEP, i.e 2,000 FTU/kg (LD), NC+high-dose CEP, i.e. 4,000 FTU/kg (HD), LD with reduced Ca/P (LDR), and HD with reduced Ca/P (HDR). At week 4, blood samples were collected from all pigs. Compared to PC, NC reduced the serum leucine and phenylalanine concentrations; however, LD recovered their levels. Using trypsinolysis and mass spectrometry, 703 serum proteins were identified and quantified, wherein 25 were found to be differentially expressed among groups. Hierarchical clustering showed a clear separation in proteins identified among dietary groups. Compared to NC, 23 and 24 proteins were found to be differentially expressed in serum of LD and HD groups, respectively, with some important proteins in growth regulation such as SELENOP being upregulated and the IGFBP family being downregulated in these groups. A positive correlation was detected between growth and abundance of BGN, TLN1, PDLIM1 and COL1A2 that are involved in bone mineralization and muscle structure development. Thus, CEP improved the serum profile of some essential AA and affected the expression of proteins involved in regulation of growth in pigs fed with VLP diets.


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