In-situ production of silver nanobiocomposite using surface layer protein of Lactobacillus helveticus and aqueous extract of dried Juglans regia green husk and investigation of antibacterial activity

2021 ◽  
Author(s):  
Fatemeh Rahimzadeh ◽  
Parinaz Ghadam ◽  
Rouha Kasra-Kermanshahi ◽  
Mahboobeh Zarrabi
Keyword(s):  
Antibacterial Activity ◽  
Surface Layer ◽  
Aqueous Extract ◽  
Juglans Regia ◽  
Lactobacillus Helveticus ◽  
Surface Layer Protein ◽  
In Situ Production

scholarly journals In Situ Production of Silver Bio Nanoparticles from Marine Biosurfactant Bacteria and Evaluation of Its Antibacterial Activity

2019 ◽  
Vol 6 (5) ◽  
pp. 5-11
Author(s):  
M. Indhuja ◽  
D. Kavitha ◽  
P. Selvamaleeswaran ◽  
A. Palanisamy ◽  
M. Sureshkumar
Keyword(s):  
Antibacterial Activity ◽  
In Situ Production

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

Downflow Bubble Column Electrochemical Reactor (DBCER): In-situ production of H2O2 and O3 to conduct Electroperoxone Process

2021 ◽  
pp. 105148
Author(s):  
Germán Santana-Martínez ◽  
Gabriela Roa-Morales ◽  
Leobardo Gómez-Olivan ◽  
Ever Peralta-Reyes ◽  
Rubí Romero ◽  
...  
Keyword(s):  
Bubble Column ◽  
Electrochemical Reactor ◽  
In Situ Production

scholarly journals Biosynthesis, characterization, and antibacterial activity of ZnO nanoaggregates using aqueous extract from Anacardium occidentale leaf: comparative study of different precursors

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Eric Kwabena Droepenu ◽  
Ebenezer Aquisman Asare ◽  
Boon Siong Wee ◽  
Rafeah Binti Wahi ◽  
Frederick Ayertey ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antibacterial Activity ◽  
Comparative Study ◽  
Aqueous Extract ◽  
Zinc Chloride ◽  
Zinc Acetate ◽  
Zinc Acetate Dihydrate ◽  
Inhibition Zone ◽  
Anacardium Occidentale ◽  
Acetate Dihydrate

Abstract Background Various parts of Anacardium occidentale plant possess curative qualities like antidiabetic, anti-inflammatory, antibacterial, antifungal, and antioxidant. Aqueous extract of this plant leaf was used in biosynthesizing zinc oxide (ZnO) nanoaggregates using two precursors of zinc salt (zinc acetate dihydrate [Zn(CH3COO)2∙2H2O] and zinc chloride [ZnCl2]). The synthesized ZnO samples were used in a comparative study to investigate the antibacterial activity against selected Gram-positive and Gram-negative microbes [Staphylococcus aureus, Exiguobacterium aquaticum (Gram +ve) and Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii (Gram −ve)]. The synthesized ZnO nanoaggregates from the two precursors were characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive x-ray spectroscopy (EDX) techniques. Results Micrographs of SEM and TEM confirmed nanoparticles agglomerated into aggregates. While spherical nanoaggregates were identified in samples prepared from Zn(CH3COO)2∙2H2O, flake-like structures were identified in samples synthesized from ZnCl2. Particle size determined by TEM was 107.03 ± 1.54 nm and 206.58 ± 1.86 nm for zinc acetate dihydrate and zinc chloride precursors respectively. ZnO nanoaggregate synthesized using zinc acetate as precursor gave higher antibacterial activity than its counterpart, zinc chloride with K. pneumonia recording the highest inhibition zone of 2.08 ± 0.03 mm (67.53%) whereas S. aureus recorded the least inhibition zone of 1.06 ± 0.14 mm (34.75%) for ZnO nanoaggregate from zinc chloride precursor. Also, antibacterial activity increases with increasing concentration of the extract in general. However, A. baumannii, E. aquaticum, and K. pneumoniae did not follow the continuity trend with regards to the 250 ppm and 500 ppm concentrations. Conclusion Biosynthesis of ZnO nanoaggregates using aqueous extract of A. occidentale leaf from zinc acetate dihydrate and zinc chloride as precursors was successful with the formation of nanospheres and nanoflakes. The study suggested that A. occidentale sp. could be an alternative source for the production of ZnO nanoparticles and are efficient antibacterial compounds against both Gram +ve and Gram −ve microbes with its promising effect against infectious bacteria.

scholarly journals Riboflavin Production in Lactococcus lactis: Potential for In Situ Production of Vitamin-Enriched Foods

2004 ◽  
Vol 70 (10) ◽  
pp. 5769-5777 ◽  
Author(s):  
Catherine Burgess ◽  
Mary O'Connell-Motherway ◽  
Wilbert Sybesma ◽  
Jeroen Hugenholtz ◽  
Douwe van Sinderen
Keyword(s):  
Functional Analysis ◽  
Lactic Acid ◽  
Lactococcus Lactis ◽  
Regulatory Region ◽  
Northern Hybridization ◽  
Vitamin B ◽  
Fermented Foods ◽  
Riboflavin Production ◽  
In Situ Production

ABSTRACT This study describes the genetic analysis of the riboflavin (vitamin B2) biosynthetic (rib) operon in the lactic acid bacterium Lactococcus lactis subsp. cremoris strain NZ9000. Functional analysis of the genes of the L. lactis rib operon was performed by using complementation studies, as well as by deletion analysis. In addition, gene-specific genetic engineering was used to examine which genes of the rib operon need to be overexpressed in order to effect riboflavin overproduction. Transcriptional regulation of the L. lactis riboflavin biosynthetic process was investigated by using Northern hybridization and primer extension, as well as the analysis of roseoflavin-induced riboflavin-overproducing L. lactis isolates. The latter analysis revealed the presence of both nucleotide replacements and deletions in the regulatory region of the rib operon. The results presented here are an important step toward the development of fermented foods containing increased levels of riboflavin, produced in situ, thus negating the need for vitamin fortification.

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