scholarly journals Effect of Active Coatings Containing Lippa citriodora Kunth. Essential Oil on Bacterial Diversity and Myofibrillar Proteins Degradation in Refrigerated Large Yellow Croaker

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1787
Author(s):  
Bo Li ◽  
Xuesong Wang ◽  
Xin Gao ◽  
Jun Mei ◽  
Jing Xie
Keyword(s):  
Essential Oil ◽  
Bacterial Diversity ◽  
Carbonyl Compounds ◽  
Large Yellow Croaker ◽  
Myofibrillar Proteins ◽  
Refrigerated Storage ◽  
Tertiary Structures ◽  
Transmission Electron ◽  
Α Helix ◽  
Β Sheet

The research evaluated the effects of locust bean gum (LBG) and sodium alginate (SA) active coatings containing 0.15, 0.30 or 0.60% lemon verbena (Lippa citriodora Kunth.) essential oil (LVEO) on the bacterial diversity and myofibrillar proteins (MPs) of large yellow croaker during refrigerated storage at 4 °C for 18 days. Variability in the dominant bacterial community in different samples on the 0, 9th and 18th day was observed. Pseudomonas and Shewanella were the two major genera identified during refrigerated storage. At the beginning, the richness of Pseudomonas was about 37.31% and increased for control (CK) samples during refrigerated storage, however, the LVEO-treated samples increased sharply from day 0 to the 9th day and then decreased. LBG-SA coatings containing LVEO treatments significantly delayed MPs oxidation by retarding the formation of free carbonyl compounds and maintaining higher sulfhydryl content, higher Ca2+-ATPase activity, better organized secondary (higher contents of α-helix and β-sheet) and tertiary structures during refrigerated storage. The transmission electron microscope (TEM) images showed that the integrity of the sarcomere was damaged; the boundaries of the H-, A-, and I-bands, Z-disk, and M-line were fuzzy in the CK samples at the end of storage. However, the LVEO-treated samples were still regular in appearance with distinct dark A-bands, light I-bands, and Z-disk. In brief, LBG-SA active coatings containing LVEO treatments suggested a feasible method for protecting the MPs of large yellow croaker during refrigerated storage.

Effects of salt concentrations on the structural transitions of peptide-amphiphile solution

2014 ◽  
Vol 1622 ◽  
pp. 147-152 ◽  
Author(s):  
Takahiro Otsuka ◽  
Atsushi Hotta
Keyword(s):  
Salt Concentration ◽  
Hierarchical Structures ◽  
Cd Spectroscopy ◽  
Structural Transitions ◽  
Peptide Amphiphile ◽  
Molecular Conformations ◽  
Multi Scale ◽  
Transmission Electron ◽  
Α Helix ◽  
Β Sheet

ABSTRACTA new peptide amphiphile (PA) called C16-W3K has hierarchical structures, presenting unique solution states, micelle structures, and secondary structures. In this work, the effects of salt (sodium dihydrogenorthophosphate) concentration on the hierarchical structural transitions of the C16-W3K solution due to its active hydrogen bonding in the peptide were discussed. In order to analyze the effects of salt on the structural transitions, the mechanical and structural analyses were conducted by viscosity measurements, transmission electron microscopy (TEM), and circular dichroic (CD) spectroscopy. It was found that the C16-W3K solutions with different salt concentrations presented different multi-scale structural transitions from spherical micelles with α-helix molecular conformations in the sol state to wormlike micelles with β-sheet conformations in the gel state. Additionally, we found that the speed of transition increased as the salt concentration increased and the conformational ratio of β-sheet to α-helix in the solutions increased with the increase in the salt concentration.

scholarly journals Shelf-Life Extension of Large Yellow Croaker (Larimichthys crocea) Using Active Coatings Containing Lemon Verbena (Lippa citriodora Kunth.) Essential Oil

2021 ◽  
Vol 8 ◽  
Author(s):  
Bo Li ◽  
Xuesong Wang ◽  
Xin Gao ◽  
Xuan Ma ◽  
Leilei Zhang ◽  
...  
Keyword(s):  
Essential Oil ◽  
Shelf Life ◽  
Life Extension ◽  
Large Yellow Croaker ◽  
Refrigerated Storage ◽  
Larimichthys Crocea ◽  
Organoleptic Evaluation ◽  
Active Coating ◽  
Related Compounds ◽  
Lemon Verbena

Active coating could improve the fish quality and extend the shelf life. This study investigates the effect of locust bean gum (LBG) and sodium alginate (SA) active coatings containing lemon verbena (Lippa citriodora Kunth.) essential oil (LVEO) emulsions on microbiological, physicochemical and organoleptic evaluation of large yellow croaker (Larimichthys crocea) samples during refrigerated storage at 4°C. Results showed that LBG-SA coatings incorporated with 0.30 or 0.60% LVEO emulsions significantly inhibited the growth of mesophile bacteria, Pseudomonas spp., H2S-producing bacteria, lactic acid bacteria (LAB) and psychrophilic bacteria, and reduce the productions of trimethylamine (TMA), total volatile basic nitrogen (TVB-N) and ATP-related compounds. Further, the LVEO treatments also retarded the water migration and maintained the organoleptic evaluation results of large yellow croaker during storage at 4°C. In conclusion, the LBG-SA active coatings incorporated with LVEO emulsions maintained the quality and extended the shelf life of large yellow croaker during refrigerated storage.

scholarly journals Membrane-Dependent Amyloid Aggregation of Human BAX α9 (173-192)

2020 ◽  
Author(s):  
David A. Price ◽  
Tayler D. Hill ◽  
Kaitlyn A. Hutson ◽  
Blaze W. Rightnowar ◽  
Sean D. Moran
Keyword(s):  
Mitochondrial Outer Membrane ◽  
Mitochondrial Outer Membrane Permeabilization ◽  
2D Ir ◽  
Transmission Electron ◽  
Amyloid Aggregates ◽  
Family Protein ◽  
Small Unilamellar Vesicles ◽  
Α Helix ◽  
Β Sheet ◽  
Prior Models

ABSTRACTMitochondrial outer membrane permeabilization, which is a critical step in apoptosis, is initiated upon transmembrane insertion of the C-terminal α-helix (α9) of the pro-apoptotic Bcl-2 family protein BAX. The isolated α9 fragment (residues 173-192) is also competent to disrupt model membranes, and the structures of its membrane-associated oligomers are of interest in understanding the potential roles of this sequence in apoptosis. Here, we used ultrafast two-dimensional infrared (2D IR) spectroscopy, thioflavin T binding, and transmission electron microscopy to show that the synthetic BAX α9 peptide (α9p) forms amyloid aggregates in solution and on the surfaces of anionic small unilamellar vesicles (SUVs). Its inherent amyloidogenicity was predicted by sequence analysis, and 2D IR spectra reveal that SUVs modulate the β-sheet structures of the resulting amyloid species. These results contradict prior models of transmembrane α9p pores and motivate further examination of the formation or suppression of BAX amyloids in apoptosis.

scholarly journals Morphological Transformation of Peptide Nanoassemblies through Conformational Transition of Core-forming Peptides

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 39
Author(s):  
Tomonori Waku ◽  
Naoyuki Hirata ◽  
Masamichi Nozaki ◽  
Kanta Nogami ◽  
Shigeru Kunugi ◽  
...  
Keyword(s):  
Conformational Transition ◽  
Morphological Transformation ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Solvent Environment ◽  
Ph Conditions ◽  
Α Helix ◽  
Micro Reactors ◽  
External Stimuli ◽  
Β Sheet

Morphological control of nanostructures that are composed of amphiphilic di- or tri-block molecules by external stimuli broadens their applications for molecular containers, nanoreactors, and controlled release materials. In this study, triblock amphiphiles comprising oligo(ethylene glycol), oligo(l-lysine), and tetra(l-phenylalanine) were prepared for the construction of nanostructures that can transform accompanying α-to-β transition of core-forming peptides. Circular dichroic (CD) measurements showed that the triblock amphiphiles adopted different secondary structures depending on the solvent environment: they adopt β-sheet structures in aqueous solution, while α-helix structures in 25% 2,2,2-trifluoroethanol (TFE) solution under basic pH conditions. Transmission electron microscopic (TEM) observation revealed that the triblock amphiphiles formed vesicle structures in 25% TFE aq. Solvent exchange from 25% TFE to water induced morphological transformation from vesicles to arc-shaped nanostructures accompanying α-β conformational transition. The transformable nanostructures may be useful as novel smart nanomaterials for molecular containers and micro reactors.

Scorpion toxin-potassium channel interaction law and its applications.

2020 ◽  
Vol 01 ◽  
Author(s):  
Zheng Zuo ◽  
Zongyun Chen ◽  
Zhijian Cao ◽  
Wenxin Li ◽  
Yingliang Wu
Keyword(s):  
Potassium Channel ◽  
Scorpion Toxin ◽  
Scorpion Toxins ◽  
Toxin Binding ◽  
Channel Interaction ◽  
Binding Interface ◽  
Α Helix ◽  
Interaction Law ◽  
Binding Interfaces ◽  
Β Sheet

: The scorpion toxins are the largest potassium channel-blocking peptide family. The understanding of toxin binding interfaces is usually restricted by two classical binding interfaces: one is the toxin α-helix motif, the other is the antiparallel β-sheet motif. In this review, such traditional knowledge was updated by another two different binding interfaces: one is BmKTX toxin using the turn motif between the α-helix and antiparallel β-sheet domains as the binding interface, the other is Ts toxin using turn motif between the β-sheet in the N-terminal and α-helix domains as the binding interface. Their interaction analysis indicated that the scarce negatively charged residues in the scorpion toxins played a critical role in orientating the toxin binding interface. In view of the toxin negatively charged amino acids as “binding interface regulator”, the law of scorpion toxin-potassium channel interaction was proposed, that is, the polymorphism of negatively charged residue distribution determines the diversity of toxin binding interfaces. Such law was used to develop scorpion toxin-potassium channel recognition control technique. According to this technique, three Kv1.3 channel-targeted peptides, using BmKTX as the template, were designed with the distinct binding interfaces from that of BmKTX through modulating the distribution of toxin negatively charged residues. In view of the potassium channel as the common targets of different animal toxins, the proposed law was also shown to helpfully orientate the binding interfaces of other animal toxins. Clearly, the toxin-potassium channel interaction law would strongly accelerate the research and development of different potassium channelblocking animal toxins in the future.

scholarly journals Nanostructure of bioactive glass affects bone cell attachment via protein restructuring upon adsorption

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ukrit Thamma ◽  
Tia J. Kowal ◽  
Matthias M. Falk ◽  
Himanshu Jain
Keyword(s):  
Bioactive Glass ◽  
Cell Response ◽  
Interfacial Layer ◽  
Cell Attachment ◽  
Bone Cell ◽  
Nano Structure ◽  
Rgd Sequence ◽  
Engineered Tissue ◽  
Α Helix ◽  
Β Sheet

AbstractThe nanostructure of engineered bioscaffolds has a profound impact on cell response, yet its understanding remains incomplete as cells interact with a highly complex interfacial layer rather than the material itself. For bioactive glass scaffolds, this layer comprises of silica gel, hydroxyapatite (HA)/carbonated hydroxyapatite (CHA), and absorbed proteins—all in varying micro/nano structure, composition, and concentration. Here, we examined the response of MC3T3-E1 pre-osteoblast cells to 30 mol% CaO–70 mol% SiO2 porous bioactive glass monoliths that differed only in nanopore size (6–44 nm) yet resulted in the formation of HA/CHA layers with significantly different microstructures. We report that cell response, as quantified by cell attachment and morphology, does not correlate with nanopore size, nor HA/CHO layer micro/nano morphology, or absorbed protein amount (bovine serum albumin, BSA), but with BSA’s secondary conformation as indicated by its β-sheet/α-helix ratio. Our results suggest that the β-sheet structure in BSA interacts electrostatically with the HA/CHA interfacial layer and activates the RGD sequence of absorbed adhesion proteins, such as fibronectin and vitronectin, thus significantly enhancing the attachment of cells. These findings provide new insight into the interaction of cells with the scaffolds’ interfacial layer, which is vital for the continued development of engineered tissue scaffolds.

scholarly journals Effect of Chitosan Coating Incorporated with Artemisia fragrans Essential Oil on Fresh Chicken Meat during Refrigerated Storage

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 716
Author(s):  
Milad Yaghoubi ◽  
Ali Ayaseh ◽  
Kazem Alirezalu ◽  
Zabihollah Nemati ◽  
Mirian Pateiro ◽  
...  
Keyword(s):  
Essential Oil ◽  
Shelf Life ◽  
Thiobarbituric Acid ◽  
Chicken Meat ◽  
Refrigerated Storage ◽  
Quality Properties ◽  
Overall Acceptability ◽  
Chitosan Coating ◽  
The Impact ◽  
Organoleptic Attributes

The present study was conducted to assess the impact of chitosan coating (1%) containing Artemisia fragrans essential oil (500, 1000, and 1500 ppm) as antioxidant and antimicrobial agent on the quality properties and shelf life of chicken fillets during refrigerated storage. After packaging meat samples, physicochemical, microbiological, and organoleptic attributes were evaluated at 0, 3, 6, 9, and 12 days at 4 °C. The results revealed that applied chitosan (CH) coating in combination with Artemisia fragrans essential oils (AFEOs) had no significant (p < 0.05) effects on proximate composition among treatments. The results showed that the incorporation of AFEOs into CH coating significantly reduced (p < 0.05) pH, thiobarbituric acid reactive substances (TBARS), and total volatile base nitrogen (TVB-N), especially for 1% CH coating + 1500 ppm AFEOs, with values at the end of storage of 5.58, 1.61, and 2.53, respectively. The coated samples also displayed higher phenolic compounds than those obtained by uncoated samples. Coated chicken meat had, significantly (p < 0.05), the highest inhibitory effects against microbial growth. The counts of TVC (total viable counts), coliforms, molds, and yeasts were significantly lower (p < 0.05) in 1% CH coating + 1500 ppm AFEOs fillets (5.32, 3.87, and 4.27 Log CFU/g, respectively) at day 12. Organoleptic attributes of coated samples also showed the highest overall acceptability scores than uncoated ones. Therefore, the incorporation of AFEOs into CH coating could be effectively used for improving stability and shelf life of chicken fillets during refrigerated storage.

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