scholarly journals Potential Probiotic Enterococcus faecium OV3-6 and Its Bioactive Peptide as Alternative Bio-Preservation

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2264
Author(s):  
Thiwanya Choeisoongnern ◽  
Sasithorn Sirilun ◽  
Rungaroon Waditee-Sirisattha ◽  
Komsak Pintha ◽  
Sartjin Peerajan ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Ribosomal Proteins ◽  
Starter Culture ◽  
Heat Stability ◽  
Fermented Food ◽  
E Coli ◽  
Active Peptide ◽  
Wide Ph Range ◽  
Small Intestinal ◽  
Ph Range

Probiotic Enterococcus faecium OV3-6 and its secreted active peptide were characterized and investigated. The strain survived in simulated gastric and small intestinal conditions at 88.16% and 94.33%, respectively. The safety assessment revealed that the strain was shown α-hemolysis and susceptible to most clinically relevant antibiotics, but intermediate sensitivity to erythromycin and kanamycin was found. It does not harbor any virulence genes except for the efaAfm gene. Both of its living cells and the cell-free supernatants (CFS) of the strain significantly reduced the adhesion of E. coli and S. Typhi on Caco-2 cells. The strain can regulate the secretion of pro and inflammatory cytokines, IL-6 and IL-12 and induce the secretion of anti-inflammatory IL-10 of the Caco-2 cell. The strain can prevent the growth of Gram-positive strains belonging to the genera Bacillus, Carnobacterium, Listeria, and Staphylococcus. It also presented the entP gene that involves the production of bacteriocin named enterocin P. The antimicrobial peptide was matched 40% with 50S ribosomal proteins L29 (7.325 kDa), as revealed by LC-MS/MS. This active peptide exhibits heat stability, is stable over a wide pH range of 2−10, and maintains its activity at −20 and 4 °C for 12 weeks of storage. Altogether, E. faecium OV3-6 thus has potential for consideration as a probiotic and bio-preservative for applied use as a fermented food starter culture and in functional food or feed industries.

scholarly journals Production Optimization of an Active β-Galactosidase of Bifidobacterium animalis in Heterologous Expression Systems

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Xinxin Xu ◽  
Xiaohu Fan ◽  
Chao Fan ◽  
Xing Qin ◽  
Bo Liu ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Culture Medium ◽  
Specific Activity ◽  
Food Additives ◽  
Production Optimization ◽  
E Coli ◽  
Bifidobacterium Animalis ◽  
Wide Ph Range ◽  
Heterologous Expression Systems ◽  
Ph Range

β-Galactosidase (E.C.3.2.1.23) catalyzes the hydrolysis of lactose into glucose and galactose and the synthesis of galacto-oligosaccharides as well. The β-galactosidases from bacteria, especially lactobacilli, and yeast have neutral pH and are much more likely to be developed as food additives. However, the challenges of cumbersome purification, product toxicity, and low yield in protein production have limited the commercialization of many excellent candidates. In this study, we identified a β-galactosidase gene (bg42-106) in Bifidobacterium animalis ACCC05790 and expressed the gene product in Escherichia coli BL21(DE3) and Pichia pastoris GS115, respectively. The recombinant bG42-106 purified from E. coli cells was found to be optimally active at pH 6.0 and 60°C and had excellent stability over a wide pH range (5.0–8.0) and at high temperature (60°C). The specific activity of bG42-106 reached up to 2351 U/mg under optimal conditions. The galacto-oligosaccharide yield was 24.45 g/L after incubation with bG42-106 at 60°C for 2 h. When recombinant bG42-106 was expressed in Pichia pastoris GS115, it was found in the culture medium but only at a concentration of 1.73 U/ml. To increase its production, three strategies were employed, including codon optimization, disulfide formation, and fusion with a Cherry tag, with Cherry-tag fusion being most effective. The culture medium of P. pastoris that expressed Cherry-tagged bG42-106 contained 24.4 U/mL of β-galactosidase activity, which is 14-fold greater than that produced by culture of P. pastoris harboring wild-type bG42-106.

scholarly journals PENAMBAHAN BAKTERI ASAM LAKTAT UNTUK MENINGKATKAN KUALITAS, KEAMANAN DAN DAYA SIMPAN ROTI

Pro Food ◽  
2018 ◽  
Vol 4 (2) ◽  
pp. 333
Author(s):  
Moegiratul Amaro ◽  
Mutia Devi Ariyana ◽  
Wiharyani Werdiningsih ◽  
Baiq Rien Handayani ◽  
Nazaruddin Nazaruddin ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Shelf Life ◽  
Starter Culture ◽  
Food Additives ◽  
Microbiological Quality ◽  
Fermented Food ◽  
Natural Preservative ◽  
E Coli ◽  
Baking Process

ABSTRACT The changes of people consumtion patterns demands a healthier bread product and tends to be organic food without use synthetic food additives that brings various consequences to health. This condition leads to the development of food additives which has effectiveness equivalent to synthetic food additive but safe for health especially if consumed long term. Lactic acid bacteria is a bacteria that hass been widely used in fermented food production process. Making bread using lactic acid bacteria begins with sourdough or acid dough consisting of flour and water fermented with lactic acid bacteria either derived from a particular natural contaminant from flour or from a starter culture containing one or more known lactic acid bacteria. Various product of actic acid bacteria metabolism such as lactic acid, acetic acid, exopollysaccharide and antimicrobial compounds such as bacteriocin make lactic acid bacteria application in baking process have to the potential to improve microbiological quality and bread shelf-life. This research aims to study the effect of lactic acid bacteria addition as a natural preservative in the baking process. The ability of lactic acid bacteria to evolve naturally from fermented flour and water promises the potential for easy sourdough preparation and can be used continuously as  a natural preservative that will save production cost. The parameters to be determined include evaluation of lactic acid bacteria and yeast growth on dough and determination of moisture content as well as total bacteris, mold and E.coli an bread. Key words: bread, lactic acid bacteria, preservatives, shelf-life, food safety ABSTRAK Pergeseran pola konsumsi masyarakat menuntut adanya produk roti yang lebih sehat dan cenderung bersifat organik tanpa penggunaan Bahan Tambahan Makanan (BTM) sintetis yang membawa berbagai konsekuensi terhadap kesehatan. Kondisi ini mengarah pada berkembangnya pencarian BTM yang memiliki efektifitas yang setara dengan BTM sintetis namun aman bagi kesehatan terutama jika dikonsumsi jangka panjang. Bakteri Asam Laktat (BAL) merupakan golongan bakteri yang telah digunakan secara luas dalam proses produksi makanan fermentasi. Pembuatan roti menggunakan BAL diawali dengan sourdough atau adonan asam yang terdiri atas tepung dan air yang difermentasi dengan BAL baik yang berasal dari  kontaminan alami tertentu dari tepung atau dari suatu kultur starter yang mengandung satu atau lebih BAL yang sudah diketahui jenisnya. Berbagai produk hasil metabolisme BAL seperti asam laktat, asam asetat, eksopolisakarida dan senyawa antimikroba seperti bakteriosin menjadikan aplikasi BAL pada proses pembuatan roti berpotensi meningkatkan kualitas mikrobiologis dan daya simpan roti. Penelitian ini secara khusus bertujuan untuk mempelajari pengaruh penambahan BAL sebagai pengawet alami dalam proses pembuatan roti. Kemampuan BAL untuk berkembang secara alami dari tepung dan air yang difermentasi menjanjikan potensi penyediaan sourdough yang mudah dibuat dan dapat digunakan secara kontinyu sebagai pengawet alami sehingga akan menghemat biaya produksi. Parameter yang akan ditentukan meliputi evaluasi pertumbuhan BAL dan yeast pada adonan dan penentuan kadar air serta total bakteri, kapang dan E. coli pada roti.   Kata kunci: roti, bakteri asam laktat, pengawet, daya simpan, keamanan pangan.

PURIFICATION AND PROPERTIES OF A RIBOSOMAL PEPTIDASE FROM ESCHERICHIA COLI B

1965 ◽  
Vol 43 (10) ◽  
pp. 1643-1652 ◽  
Author(s):  
C. S. Tsai ◽  
A. T. Matheson
Keyword(s):  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Basic Protein ◽  
Small Scale ◽  
E Coli ◽  
Purification And Properties ◽  
Optimum Ph ◽  
Ph Range ◽  
Escherichia Coli B ◽  
Optimum Ph Range

A leucylglycine-splitting enzyme from E. coli ribosomes has been purified and its properties studied. The ribosomal proteins were solubilized by disrupting the ribosomal particles in 1 M Tris. As purification proceeded the ionic strength required to keep the proteins in solution steadily decreased until, in the later stages, the enzyme could be fractionated on ion-exchange columns at low ionic strengths. The ribosomal peptidase requires K+ or Cs+ and Mn2+ or Mg2+ for full activity and is inhibited by Na+ and Li+. It is completely inhibited by EDTA. The enzyme, which is a basic protein with no absorbancy maximum in the 280 mμ region of the spectrum, has a broad optimum pH range from 7.5 to 9.2. On small-scale preparations over a 1000-fold purification has been obtained.

Multiple molecular forms of avian aldolases. II. Enzymic properties and amino acid composition of chicken (Gattus domesticus) breast muscle aldolase

1969 ◽  
Vol 47 (5) ◽  
pp. 527-534 ◽  
Author(s):  
Ronald R. Marquardt
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Heat Stability ◽  
Breast Muscle ◽  
Molecular Forms ◽  
Ph Optimum ◽  
Wide Ph Range ◽  
Michaelis Constants ◽  
Ph Range

Several properties of crystalline chicken (Gallus domesticus) breast muscle aldolase (fructose 1,6-diphosphate–D-glyceraldehyde 3-phosphate lyase, EC 4.1.2.13) were determined. The enzyme was found to have a broad pH optimum centered around pH 7.1 and to be remarkably stable over a wide pH range. The temperature coefficient Q10 is 2.6 in the range from 10 to 35 °C. The enzyme is stable at 48 °C for 10 min and almost completely inactivated at 55 °C. The apparent Michaelis constants for fructose 1,6-diphosphate and fructose 1-phosphate were 4.2 × 10−5 M and 1.7 × 10−2 M, respectively. The phosphate inhibitor constant (K1) was 5.5 × 10−3 M.Chicken breast muscle aldolase is similar to the rabbit enzyme in many of the above properties, although there are significant differences in heat stability and amino acid composition.

A novel NhaD-type Na+/H+ antiporter from the moderate halophile and alkaliphile Halomonas alkaliphila

2017 ◽  
Vol 63 (7) ◽  
pp. 596-607 ◽  
Author(s):  
Yanhong Wang ◽  
Na Song ◽  
Lina Yang ◽  
Heba Abdel-motaal ◽  
Rui Zhang ◽  
...  
Keyword(s):  
Membrane Vesicles ◽  
Activity Profile ◽  
Moderate Halophile ◽  
E Coli ◽  
Significant Difference ◽  
Dependent Activity ◽  
Wide Ph Range ◽  
Ph Dependent ◽  
Ph Range ◽  
Selection Of

In this study, a NhaD-type Na+/H+ antiporter gene designated Ha-nhaD was obtained by selection of genomic DNA from the moderate halophile and alkaliphile Halomonas alkaliphila in Escherichia coli KNabc lacking 3 major Na+/H+ antiporters. The presence of Ha-NhaD conferred tolerance of E. coli KNabc to NaCl up to 0.6 mol·L–1 and to LiCl up to 0.2 mol·L–1 and to an alkaline pH. pH-dependent Na+(Li+)/H+ antiport activity was detected from everted membrane vesicles prepared from E. coli KNabc/pUC-nhaD but not those of KNabc/pUC18. Ha-NhaD exhibited Na+(Li+)/H+ antiport activity over a wide pH range from 7.0 to 9.5, with the highest activity at pH 9.0. Protein sequence alignment and phylogenetic analysis revealed that Ha-NhaD is significantly different from the 7 known NhaD-type Na+/H+ antiporters, including Dw-NhaD, Dl-NhaD, Vp-NhaD, Vc-NhaD, Aa-NhaD, He-NhaD, and Ha-NhaD1. Although Ha-NhaD showed a closer phylogenetic relationship with Ha-NhaD2, a significant difference in pH-dependent activity profile exists between Ha-NhaD and Ha-NhaD2. Taken together, Ha-nhaD encodes a novel pH-dependent NhaD-type Na+/H+ antiporter.

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

Structural similarity of ribosomes from E. coli and A. salina

1978 ◽  
Vol 36 (2) ◽  
pp. 242-243
Author(s):  
M. Boublik ◽  
R.M. Wydro ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Ribosomal Proteins ◽  
Direct Evidence ◽  
Structural Similarity ◽  
Carbon Support ◽  
Artemia Salina ◽  
Uranyl Acetate ◽  
Biological Assays ◽  
E Coli ◽  
And Function ◽  
Fine Carbon

Ribosomes are ribonucleoprotein particles necessary for processing the genetic information of mRNA into proteins. Analogy in composition and function of ribosomes from diverse species, established by biochemical and biological assays, implies their structural similarity. Direct evidence obtained by electron microscopy seems to be of increasing relevance in understanding the structure of ribosomes and the mechanism of their role in protein synthesis.The extent of the structural homology between prokaryotic and eukaryotic ribosomes has been studied on ribosomes of Escherichia coli (E.c.) and Artemia salina (A.s.). Despite the established differences in size and in the amount and proportion of ribosomal proteins and RNAs both types of ribosomes show an overall similarity. The monosomes (stained with 0.5% aqueous uranyl acetate and deposited on a fine carbon support) appear in the electron micrographs as round particles with a diameter of approximately 225Å for the 70S E.c. (Fig. 1) and 260Å for the 80S A.s. monosome (Fig. 2).

Protein-induced conformational changes in 16S rRNA during assembly of the Escherichia Coli 30S ribosomal subunit: A STEM study

1987 ◽  
Vol 45 ◽  
pp. 910-911
Author(s):  
M. Boublik ◽  
V. Mandiyan ◽  
J.F. Hainfeld ◽  
J.S. Wall
Keyword(s):  
16S Rrna ◽  
Conformational Changes ◽  
Ribosomal Proteins ◽  
Structural Changes ◽  
Ribosomal Subunit ◽  
Compact Structure ◽  
E Coli ◽  
Freeze Dried ◽  
16S Rna ◽  
30S Subunit

The aim of this study is to understand the mechanism of 16S rRNA folding into the compact structure of the small 30S subunit of E. coli ribosome. The assembly of the 30S E. coli ribosomal subunit is a sequence of specific interactions of 16S rRNA with 21 ribosomal proteins (S1-S21). Using dedicated high resolution STEM we have monitored structural changes induced in 16S rRNA by the proteins S4, S8, S15 and S20 which are involved in the initial steps of 30S subunit assembly. S4 is the first protein to bind directly and stoichiometrically to 16S rRNA. Direct binding also occurs individually between 16S RNA and S8 and S15. However, binding of S20 requires the presence of S4 and S8. The RNA-protein complexes are prepared by the standard reconstitution procedure, dialyzed against 60 mM KCl, 2 mM Mg(OAc)2, 10 mM-Hepes-KOH pH 7.5 (Buffer A), freeze-dried and observed unstained in dark field at -160°.

Polarographic and spectrophotometric behaviour of some N-p-phenyl substituted benzamidines

1991 ◽  
Vol 56 (12) ◽  
pp. 2791-2799 ◽  
Author(s):  
Juan A. Squella ◽  
Luis J. Nuñez-Vergara ◽  
Hernan Rodríguez ◽  
Amelia Márquez ◽  
Jose M. Rodríguez-Mellado ◽  
...  
Keyword(s):  
Spectrophotometric Study ◽  
Absorption Bands ◽  
Electrochemical Parameters ◽  
Wide Ph Range ◽  
Group A ◽  
Substituent Constants ◽  
Ph Range ◽  
The Waves

Five N-p-phenyl substituted benzamidines were studied by DC and DP polarography in a wide pH range. Coulometric results show that the overall processes are four-electron reductions. Logarithmic analysis of the waves indicate that the process are irreversible. The influence of the pH on the polarographic parameters was also studied. A UV spectrophotometric study was performed in the pH range 2-13. In basic media some variations in the absorption bands were observed due to the dissociation of the amidine group. A determination of the pK values was made by deconvolution of the spectra. Correlations of both the electrochemical parameters and spectrophotometric pK values with the Hammett substituent constants were obtained.

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