High surface hydrophobicity of hemagglutinatingVibrio cholerae and other vibrios

<abstract> <p>The probiotic potential of lactic acid bacteria (LAB) isolated from Thai traditional fermented food was investigated. Forty-two samples were collected from four markets in Phra Nakhon Si Ayutthaya Province. Out of 50 isolated LAB, 6 (a3, f4, f8, K1, K4 and K9) obtained from pla-ra and bamboo shoot pickle samples showed high tolerance to gastrointestinal tract conditions. These isolates were selected to identify and characterize their probiotic properties. Isolate a3 was identified as <italic>Weissella thailandensis</italic>, isolates f4 and f8 were identified as belonging to <italic>Enterococcus thailandicus</italic> and isolates K1, K4 and K9 were determined as <italic>Limosilactobacillus fermentum</italic>. All six LAB exhibited high autoaggregation ability (93.40–95.01%), while <italic>W. thailandensis</italic> isolate a3 showed potential for coaggregation in almost all the pathogenic bacteria tested. Cell-free supernatant (CFS) obtained from all isolates did not inhibit <italic>Staphylococcus aureus</italic>. CFS derived from <italic>L. fermentum</italic> isolate K4 showed the most efficient antimicrobial activity, in particular against Gram-negative bacteria, while <italic>L. fermentum</italic> isolate K4 presented high surface hydrophobicity in the presence of xylene and n-hexane. All LAB isolates were found to be resistant to clindamycin and nalidixic acid, whereas <italic>E. thailandicus</italic> isolate f8 exhibited resistance to most of the antibiotics tested. <italic>L. fermentum</italic> isolate K4 showed promise as a suitable probiotic candidate for future applications in the food industry due to tolerance to gastrointestinal tract conditions with high surface hydrophobicity and inhibited most of the pathogens tested.</p> </abstract>

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PDMS Soft Skin Device with Deformable Micro-Diaphragm Array Fabricated with Rapid Substrate-Releasing Process

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2020.p0289 ◽

2020 ◽

Vol 32 (2) ◽

pp. 289-296

Author(s):

Hideyuki Mitsui ◽

Hiroshi Kashiwazaki ◽

Takashi Mineta ◽

◽

Keyword(s):

Contact Angle ◽

Sacrificial Layer ◽

High Surface ◽

Surface Hydrophobicity ◽

Inner Pressure ◽

Novel Method ◽

Fabrication And Characterization ◽

Releasing Process ◽

Good Agreement

This paper describes the fabrication and characterization of a prototype wettability switching soft skin device that dynamically switches its surface morphology between flat and rough states. The device, which consists of a 1-μm-thick polydimethylsiloxane (PDMS) deformable diaphragm on a PDMS substrate with a micro-bump arrays, was successfully formed with a high fabrication yield by a novel method of device releasing from a dummy substrate. In buffered hydrofluoric acid (BHF) solution, a sacrificial layer of a novolak-resin-based resist was able to be rapidly released from the OH-terminated SiO2 surface of the dummy substrate, probably due to the breaking of hydrogen bonds at the interface. The wettability of the fabricated device was reversibly switched using micro-diaphragm deformation by varying the inner pressure. When a droplet was placed on the surface in the rough state, a large contact angle of approximately 140° was obtained, close to the Cassie mode with air in the concave-deformed PDMS micro-diaphragms, which indicated a high surface hydrophobicity. During cyclic switching between the rough and flat states after second switching, the contact angle reversibly changed between 106° and 120°, in good agreement with the Wenzel mode, where the micro-diaphragm surfaces were fully wet. Additionally, we observed that the droplet did not move even on the tilted device.

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Toxic oligomers of the amyloidogenic HypF-N protein form pores in mitochondrial membranes

Scientific Reports ◽

10.1038/s41598-020-74841-z ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Maria Ylenia Farrugia ◽

Mario Caruana ◽

Stephanie Ghio ◽

Angelique Camilleri ◽

Claude Farrugia ◽

...

Keyword(s):

Mitochondrial Membrane ◽

Single Channel ◽

High Surface ◽

Amyloid Β ◽

Type A ◽

Surface Hydrophobicity ◽

Mitochondrial Membranes ◽

N Protein ◽

E Coli ◽

Ion Conducting

Abstract Studies on the amyloidogenic N-terminal domain of the E. coli HypF protein (HypF-N) have contributed significantly to a detailed understanding of the pathogenic mechanisms in neurodegenerative diseases characterised by the formation of misfolded oligomers, by proteins such as amyloid-β, α-synuclein and tau. Given that both cell membranes and mitochondria are increasingly recognised as key targets of oligomer toxicity, we investigated the damaging effects of aggregates of HypF-N on mitochondrial membranes. Essentially, we found that HypF-N oligomers characterised by high surface hydrophobicity (type A) were able to trigger a robust permeabilisation of mito-mimetic liposomes possessing cardiolipin-rich membranes and dysfunction of isolated mitochondria, as demonstrated by a combination of mitochondrial shrinking, lowering of mitochondrial membrane potential and cytochrome c release. Furthermore, using single-channel electrophysiology recordings we obtained evidence that the type A aggregates induced currents reflecting formation of ion-conducting pores in mito-mimetic planar phospholipid bilayers, with multi-level conductances ranging in the hundreds of pS at negative membrane voltages. Conversely, HypF-N oligomers with low surface hydrophobicity (type B) could not permeabilise or porate mitochondrial membranes. These results suggest an inherent toxicity of membrane-active aggregates of amyloid-forming proteins to mitochondria, and that targeting of oligomer-mitochondrial membrane interactions might therefore afford protection against such damage.

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Surface properties of the bovine casein components: relationships between structure and foaming properties

Journal of Dairy Research ◽

10.1017/s0022029900028983 ◽

1989 ◽

Vol 56 (3) ◽

pp. 495-502 ◽

Cited By ~ 14

Author(s):

Denis Lorient ◽

Brigitte Closs ◽

Jean Luc Courthaudon

Keyword(s):

Surface Tension ◽

Ionic Strength ◽

Foam Stability ◽

Covalent Binding ◽

High Surface ◽

Surface Hydrophobicity ◽

Foaming Properties ◽

Foam Formation ◽

Foaming Capacity ◽

Low Ionic Strength

SummaryIn order to optimize the use of caseins as surfactants, the surface tension, foaming capacity and stability were measured as a function of pH, ionic strength, protein concentration and polarity (modified by covalent binding of carbohydrates). We found that the caseins differ in their behaviour at the air/water interface with β-casein showing the greatest ability to decrease surface tension and to produce foams, due probably to its amphipathic structure. In experiments carried out at pH values close to pI, with low ionic strength and constant solubility (optimal conditions for foam formation), we observed a high surface hydrophobicity, a good accessibility and flexibility of peptidic side chains (evaluated by proteolysis), and a high foaming capacity parallelled by increased surface pressure. Foam stability of caseins was low compared to those of globular proteins such as β lactoglobulin.

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Adhesion Properties of Lactobacillus plantarum Dad-13 and Lactobacillus plantarum Mut-7 on Sprague Dawley Rat Intestine

Microorganisms ◽

10.3390/microorganisms9112336 ◽

2021 ◽

Vol 9 (11) ◽

pp. 2336

Author(s):

Arum Darmastuti ◽

Pratama N. Hasan ◽

Rachma Wikandari ◽

Tyas Utami ◽

Endang S. Rahayu ◽

...

Keyword(s):

Lactobacillus Plantarum ◽

Intestinal Mucosa ◽

High Surface ◽

Genomic Analysis ◽

Surface Hydrophobicity ◽

Sprague Dawley ◽

Rat Intestine ◽

Adhesion Properties ◽

Sprague Dawley Rat ◽

Probiotic Strains

Adhesion capacity is considered one of the selection criteria for probiotic strains. The purpose of this study was to determine the adhesion properties of two candidate probiotics, Lactobacillus plantarum Dad-13 and Lactobacillus plantarum Mut-7. The evaluation included the hydrophobicity of the cell surface using microbial adhesion to hydrocarbons (MATH), autoaggregation, and the adhesion of L. plantarum Dad-13 and L. plantarum Mut-7 to the intestinal mucosa of Sprague Dawley rat, followed by genomic analysis of the two L. plantarum strains. L. plantarum Dad-13 and L. plantarum Mut-7 showed a high surface hydrophobicity (78.9% and 83.5%) and medium autoaggregation ability (40.9% and 57.5%, respectively). The exposure of both isolates to the surface of the rat intestine increased the total number of lactic acid bacteria on the colon compartment, from 2.9 log CFU/cm2 to 4.4 log CFU/cm2 in L. plantarum Dad-13 treatment and to 3.86 log CFU/cm2 in L. plantarum Mut-7 treatment. The results indicate the ability of two L. plantarum to attach to the surface of the rat intestine. The number of indigenous E. coli in the colon also decreased when the compartment was exposed to L. plantarum Dad-13 and Mut-7, from 2.9 log CFU/cm2 to 1 log CFU/cm2. Genomic analysis revealed that both strains have genes related to adhesion properties that could play an important role in increasing the adherence of probiotics to the intestinal mucosa such as gene encoding fibronectin-binding protein, chaperonin heat shock protein 33 (Hsp33), and genes related to the capsule and cell wall biosynthesis. Based on these findings, we believe that L. plantarum Dad-13 and L. plantarum Mut-7 have adhesion properties to the intestinal mucosa in the rat intestine model system. The present research will be essential to elucidate the molecular mechanism associated with adhesion in our two probiotic strains.

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Characterization of Lactobacillus Isolates from Human Mouth and Feces as Probiotics

Cihan University-Erbil Scientific Journal ◽

10.24086/cuesj.v4n1y2020.pp7-12 ◽

2020 ◽

Vol 4 (1) ◽

pp. 7-12

Author(s):

Wala’a Sh. Ali ◽

Aya T. Reza

Keyword(s):

Bile Salts ◽

High Surface ◽

Lactobacillus Rhamnosus ◽

Cell Surface Hydrophobicity ◽

Surface Hydrophobicity ◽

The Other ◽

Human Beings ◽

Adhesion Ability ◽

Antibiotics Susceptibility

Probiotics are live microbes that give many health benefits to human beings and animals, the most studied and commonly used probiotics are Gram-positive bacteria; lactobacilli and bifidobacteria. At nowadays, Lactobacillus spp. constitute more than two-thirds of the total numbers of probiotic species. The present study aimed to characterize Lactobacillus that locally isolated from human mouth and feces as probiotics. A total of three Lactobacillus isolates; Lactobacillus fermentum Lb2, Lactobacillus rhamnosus Lb9, and Lactobacillus paracasei Lb10 were investigated in respect to acid and bile salts tolerance, antibiotics susceptibility, and cell surface hydrophobicity in vitro using bacterial adhesion to hydrocarbons method. In comparison with the other two isolates, the isolate L. fermentum Lb2 was able to grow in all pH values and in the presence of different concentrations of bile salts. Antibiotics susceptibility profile showed that the tested Lactobacillus isolates were sensitive to ampicillin, amoxicillin, and erythromycin, while they were resistant to the other antibiotics that used in this study. L. fermentum Lb2 exhibited high surface hydrophobicity (77.26%), while the other tested isolates; L. rhamnosus Lb9 and L. paracasei Lb10 revealed moderate adhesion abilities, 68.56% and 65%, respectively. L. fermentum Lb2 exhibited good probiotic behavior with respect to acid and bile salt tolerance as well as adhesion ability to hydrocarbons.

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The role of bacterial hydrophobicity in infection: bacterial adhesion and phagocytic ingestion

Canadian Journal of Microbiology ◽

10.1139/m88-054 ◽

1988 ◽

Vol 34 (3) ◽

pp. 287-298 ◽

Cited By ~ 76

Author(s):

Darryl R. Absolom

Keyword(s):

Surface Tension ◽

Bacterial Adhesion ◽

Liquid Surface ◽

Substrate Surface ◽

Bacterial Species ◽

High Surface ◽

Surface Hydrophobicity ◽

Bacterial Surface ◽

Liquid Surface Tension ◽

Bacterial Hydrophobicity

The role that bacterial surface hydrophobicity (surface tension) plays in determining the extent of adhesion of polymer substrates and phagocytic ingestion is reviewed. The early attachment phase in bacterial adhesion is shown to depend critically on the relative surface tensions of the three interacting phases; i.e., bacteria, substrate, and suspending liquid surface tension. When suspended in a liquid with a high surface tension such as Hanks balanced salt solution, the most hydrophobic bacteria adhere to all surfaces to the greatest extent. When the liquid surface tension (γLV) is larger than the bacterial surface tension (γBV), then for any single bacterial species the extent of adhesion decreases with increasing substrate surface tension (γSV). When γLV < γBV then adhesion increases with increasing γSV. Bacterial surface tension also determines in part the extent of phagocytic ingestion and the degree to which antibodies aspecifically adsorb onto the bacterium resulting in opsonization. The nonspecific adsorption of antibodies results in a considerable modification in the surface properties of the bacteria. Bacterial surface hydrophobicity can be altered significantly through exposure to subinhibitory concentrations of antibiotics, surfactants, lectins, etc. The effect of these changes on subsequent phagocytic ingestion is discussed.

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Identification of transmissible proteotoxic oligomer-like fibrils that expand conformational diversity of amyloid assemblies

Communications Biology ◽

10.1038/s42003-021-02466-7 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Phuong Trang Nguyen ◽

Ximena Zottig ◽

Mathew Sebastiao ◽

Alexandre A. Arnold ◽

Isabelle Marcotte ◽

...

Keyword(s):

Protein Misfolding ◽

Amyloid Fibrils ◽

High Surface ◽

Surface Hydrophobicity ◽

Structural Basis ◽

Structural Polymorphism ◽

Islet Amyloid ◽

Transient Nature ◽

Conformational Diversity ◽

Cellular Dysfunction

AbstractProtein misfolding and amyloid deposition are associated with numerous diseases. The detailed characterization of the proteospecies mediating cell death remains elusive owing to the (supra)structural polymorphism and transient nature of the assemblies populating the amyloid pathway. Here we describe the identification of toxic amyloid fibrils with oligomer-like characteristics, which were assembled from an islet amyloid polypeptide (IAPP) derivative containing an Asn-to-Gln substitution (N21Q). While N21Q filaments share structural properties with cytocompatible fibrils, including the 4.7 Å inter-strand distance and β-sheet-rich conformation, they concurrently display characteristics of oligomers, such as low thioflavin-T binding, high surface hydrophobicity and recognition by the A11 antibody, leading to high potency to disrupt membranes and cause cellular dysfunction. The toxic oligomer-like conformation of N21Q fibrils, which is preserved upon elongation, is transmissible to naïve IAPP. These stable fibrils expanding the conformational diversity of amyloid assemblies represent an opportunity to elucidate the structural basis of amyloid disorders.

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SYNTHEIS OF NI IMPREGNATED HYPERCROSSLINKED POLYSTERENE FOR CATALITIC HYDROGENATION OF D-GLUCOSE

IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA ◽

10.6060/ivkkt.20206305.6208 ◽

2020 ◽

Vol 63 (5) ◽

pp. 51-58

Author(s):

Roman V. Brovko ◽

Valentin Yu. Doluda ◽

Olga V. Lefedova ◽

Ilya A. Tarasyuk ◽

Dmitry V. Filippov ◽

...

Keyword(s):

Reaction Rate ◽

High Surface ◽

Surface Concentration ◽

Surface Hydrophobicity ◽

Hydrogenation Reaction ◽

Hypercrosslinked Polystyrene ◽

Active Metal ◽

Glucose Isomerization ◽

Rigid Matrix ◽

Type Nickel

Development of efficient catalysts is in focus of modern chemical technology for production of fine chemicals. D-sorbitol is widely used as sweetener, food additive and fuel compound is typically produced by D-glucose hydrogenation over Ni-Reney catalyst. However, this catalyst is characterized by not sufficient stability and selectivity to D-sorbitol formation. The described study is devoted to synthesis of nickel containing hypercrosslinked polystyrene for D-glucose hydrogenation process. Hypercrosslinked polystyrene is one of the representatives of crosslinked polymers with rigid matrix applicable for metal nanoparticles synthesis. However, hypercrosslinked polystyrene is characterized by high surface hydrophobicity that prevent impregnation of high amount of active metal over it surface. To overcome this disadvantage hypercrosslinked polystyrene was modified by hydrogen peroxide, chlorine and ammonia. A series of nickel based catalyst theoretically containing 25wt.% of nickel were synthesized. Modification of hypercrosslinked polystyrene results in appropriate increase in surface concentration of active metal. Synthesized Ni based catalysts were characterized by comparable Ni loading varying from 20.1 wt.% to 23.2 wt.%. Some increase in Ni loading can be subscribed to presence of surface-active groups in a case of modified hypercrosslinked polystyrene application. Mesopores surface area decrease from 126 m2/g to 69 m2/g in case of catalysts on modified hypercrosslinked polystyrene. Catalytic hydrogenation of D-glucose over synthesized Ni-containing catalysts showed considerable increase in turnover frequency (TOF) for all samples compare to commonly used Reney type nickel. Increase in TOF can be subscribed to appropriate increase of active metal surface concentration. Beside, some increase in catalyst selectivity to sorbitol took place. Considerable improvement of selectivity to sorbitol can be explained by increasing of desired D-glucose hydrogenation reaction rate, while reaction rate of D-glucose isomerization process to D-fructose remain the same. The achieved TOF for most active catalyst was found to be 0.27 s-1 and catalysts selectivity to D-sorbitol 98%.

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