Effect of the freeze-drying process on the phenotypic diversity of Pseudomonas putida strains isolated from the interior of healthy roots of Sida hermaphrodita: Phenotype microarrays (PMs)

Cryobiology ◽  
2020 ◽  
Vol 96 ◽  
pp. 145-151
Author(s):  
Łukasz Jałowiecki ◽  
Izabela Krzymińska ◽  
Magdalena Górska ◽  
Grażyna Płaza ◽  
Izabela Ratman-Kłosińska
Author(s):  
Alan S. Rudolph ◽  
Ronald R. Price

We have employed cryoelectron microscopy to visualize events that occur during the freeze-drying of artificial membranes by employing real time video capture techniques. Artificial membranes or liposomes which are spherical structures within internal aqueous space are stabilized by water which provides the driving force for spontaneous self-assembly of these structures. Previous assays of damage to these structures which are induced by freeze drying reveal that the two principal deleterious events that occur are 1) fusion of liposomes and 2) leakage of contents trapped within the liposome [1]. In the past the only way to access these events was to examine the liposomes following the dehydration event. This technique allows the event to be monitored in real time as the liposomes destabilize and as water is sublimed at cryo temperatures in the vacuum of the microscope. The method by which liposomes are compromised by freeze-drying are largely unknown. This technique has shown that cryo-protectants such as glycerol and carbohydrates are able to maintain liposomal structure throughout the drying process.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shukria Akbar ◽  
D. Cole Stevens

AbstractPredation contributes to the structure and diversity of microbial communities. Predatory myxobacteria are ubiquitous to a variety of microbial habitats and capably consume a broad diversity of microbial prey. Predator–prey experiments utilizing myxobacteria have provided details into predatory mechanisms and features that facilitate consumption of prey. However, prey resistance to myxobacterial predation remains underexplored, and prey resistances have been observed exclusively from predator–prey experiments that included the model myxobacterium Myxococcus xanthus. Utilizing a predator–prey pairing that instead included the myxobacterium, Cystobacter ferrugineus, with Pseudomonas putida as prey, we observed surviving phenotypes capable of eluding predation. Comparative transcriptomics between P. putida unexposed to C. ferrugineus and the survivor phenotype suggested that increased expression of efflux pumps, genes associated with mucoid conversion, and various membrane features contribute to predator avoidance. Unique features observed from the survivor phenotype when compared to the parent P. putida include small colony variation, efflux-mediated antibiotic resistance, phenazine-1-carboxylic acid production, and increased mucoid conversion. These results demonstrate the utility of myxobacterial predator–prey models and provide insight into prey resistances in response to predatory stress that might contribute to the phenotypic diversity and structure of bacterial communities.


Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 772
Author(s):  
Estefanía Álvarez-Castillo ◽  
Carlos Bengoechea ◽  
Antonio Guerrero

The replacement of common acrylic derivatives by biodegradable materials in the formulation of superabsorbent materials would lessen the associated environmental impact. Moreover, the use of by-products or biowastes from the food industry that are usually discarded would promote a desired circular economy. The present study deals with the development of superabsorbent materials based on a by-product from the meat industry, namely plasma protein, focusing on the effects of a freeze-drying stage before blending with glycerol and eventual injection molding. More specifically, this freeze-drying stage is carried out either directly on the protein flour or after its solubilization in deionized water (10% w/w). Superabsorbent materials obtained after this solubilization-freeze-drying process display higher Young’s modulus and tensile strength values, without affecting their water uptake capacity. As greater water uptake is commonly related to poorer mechanical properties, the proposed solubilization-freeze-drying process is a useful strategy for producing strengthened hydrophilic materials.


Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 839
Author(s):  
Karina Jasińska ◽  
Bartłomiej Zieniuk ◽  
Dorota Nowak ◽  
Agata Fabiszewska

The study aimed to evaluate the impact of selected factors of the freeze-drying process on the hydrolytic and synthetic activity of the extracellular lipases of Y. lipolytica KKP 379 and to attempt the use of the crude enzyme preparation as a biocatalyst in the synthesis of geranyl 4-hydroxyphenylpropanoate. Antioxidant and antibacterial properties of the geranyl ester derivative were also investigated in order to evaluate their usefulness as a novel food additive. The studies confirmed that freeze-drying was an effective method of dehydrating yeast supernatant and allowed for obtaining lyophilizates with low water activity from 0.055 to 0.160. The type and concentration of the additive (2–6% whey protein hydrolyzate, 0.5% and 1% ammonium sulphate) had a significant effect on the hydrolytic activity of enzyme preparations, while the selected variants of drying temperature during the freeze-drying process were not significant (10 °C and 50 °C). Low yield of geranyl 4-hydroxyphenylopropionate was shown when the lyophilized supernatant was used (5.3%), but the yield of ester synthesis increased when the freeze-dried Y. lipolytica yeast biomass was applied (47.9%). The study confirmed the antioxidant properties of the synthesized ester by the DPPH• and CUPRAC methods, as well as higher antibacterial activity against tested bacteria than its precursor with 0.125 mM MIC (minimal inhibitory concentration) against L. monocytogenes.


2010 ◽  
Vol 65 (21) ◽  
pp. 5716-5727 ◽  
Author(s):  
Sajal M. Patel ◽  
Swetaprovo Chaudhuri ◽  
Michael J. Pikal

2017 ◽  
Vol 168 ◽  
pp. 1244-1250 ◽  
Author(s):  
Kenta Bando ◽  
Yasuki Kansha ◽  
Masanori Ishizuka ◽  
Atsushi Tsutsumi

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