A muramidase from Acremonium alcalophilum hydrolyse peptidoglycan found in the gastrointestinal tract of broiler chickens

Abstract This study evaluates peptidoglycan hydrolysis by a microbial muramidase from the fungus Acremonium alcalophilum in vitro and in the gastrointestinal tract of broiler chickens. Peptidoglycan used for in vitro studies was derived from 5 gram-positive chicken gut isolate type strains. In vitro peptidoglycan hydrolysis was studied by three approaches: (a) helium ion microscopy to identify visual phenotypes of hydrolysis, (b) reducing end assay to quantify solubilization of peptidoglycan fragments, and (c) mass spectroscopy to estimate relative abundances of soluble substrates and reaction products. Visual effects of peptidoglycan hydrolysis could be observed by helium ion microscopy an…

Microencapsulation of Enteric Bacteriophages in a pH-Responsive Solid Oral Dosage Formulation Using a Scalable Membrane Emulsification Process

A scalable low-shear membrane emulsification process was used to produce microencapsulated Escherichia coli-phages in a solid oral dosage form. Uniform pH-responsive composite microparticles (mean size ~100 &micro

Directed Assembly of Cellulose Nanocrystals in Their Native Solid-State Template of a Processed Fiber Cell Wall

Funding Information: I.S. thanks The Academy of Finland (grant no. 300364) for funding this work. C.D. acknowledges funding from FAPESP (grant 13/07932‐6). P.A.P. thanks the Emil Aaltonen Foundation and Academy of Finland (grant no. 315768) for funding and ESRF for beamtime at beamline D2am (experiment 02‐01‐885). Rita Hatakka is acknowledged for her assistance with the GPC measurements. Work of M.L. was supported by the Jane and Aatos Erkko Foundation. The work is a part of the FinnCERES Bioeconomy ecosystem. Publisher Copyright: © 2021 The Authors. Macromolecular Rapid Communications published by Wiley-VCH GmbH Copyright: Copyright 2021 Elsevier B.V., All rights reserved. Nanoparticle ass…

Lämpösähköisen materiaalin lämmönjohtavuuden määrittäminen matalissa lämpötiloissa käyttäen 3ω-menetelmää

Työssä tutkittiin mittausmenetelmää lämmönjohtavuuden määrittämiseen mata- lissa lämpötiloissa. Mittaukset perustuivat 3ω menetelmään, joka on alunperin ohut- kalvoille kehitetty menetelmä lämmönjohtavuuden mittaukseen. Menetelmässä läm- mitinlangan läpi kulkeva vaihtovirta synnyttää kolminkertaisella taajudella olevan jännitteen, jonka avulla saadaan tietoa kappaleen termisistä ominaisuuksista. Mit- tauksissa kultainen lämmitinlanka höyrystettiin Kapton kalvon päälle ja tämän päälle hyvin ohut alumiinioksidikerros. Mittaukset suoritettiin pulssituubijäähdyttimeen ra- kennetussa näytteenpitimessä. Laitteiston toiminta varmistettiin huoneenlämpötilas- sa borosilikaatti- ja Kapton näytteillä.…

Bacteriophage imaging : past, present and future

The visualization of viral particles only became possible after the advent of the electron microscope. The first bacteriophage images were published in 1940 and were soon followed by many other publications that helped to elucidate the structure of the particles and their interaction with the bacterial hosts. As sample preparation improved and new technologies were developed, phage imaging became important approach to morphologically classify these viruses and helped to understand its importance in the biosphere. In this review we discuss the main milestones in phage imaging, how it affected our knowledge on these viruses and recent developments in the field. peerReviewed

Antibacterial Efficiency of Surface-Immobilized Flavobacterium-Infecting Bacteriophage

Control of bacterial diseases by bacteriophages (phages) is gaining more interest due to increasing antibiotic resistance. This has led to technologies to attach phages on surfaces to form a biomaterial that can functionally display phages that interact with bacteria, to carry out successful infection cycles. Such a material could be applied in many environments, where the target pathogens are expected. Although this approach has been applied successfully in a few studies already, the basis of the antibacterial effect by the immobilized phages is unclear, and the interpretation of the results depends on the study. Here, we studied the phage attachment density, their detachment rate and infe…

Bioimaging: Imaging Bacterial Colonies and Phage-Bacterium Interaction at Sub-Nanometer Resolution Using Helium-Ion Microscopy (Adv. Biosys. 8/2017)

Cellulose nanofibrils prepared by gentle drying methods reveal the limits of helium ion microscopy imaging

TEMPO-oxidized cellulose nanofibrils (TCNFs) have unique properties, which can be utilised in many application fields from printed electronics to packaging. Visual characterisation of TCNFs has been commonly performed using Scanning Electron Microscopy (SEM). However, a novel imaging technique, Helium Ion Microscopy (HIM), offers benefits over SEM, including higher resolution and the possibility of imaging non-conductive samples uncoated. HIM has not been widely utilized so far, and in this study the capability of HIM for imaging of TCNFs was evaluated. Freeze drying and critical point drying (CPD) techniques were applied to preserve the open fibril structure of the gel-like TCNFs. Both dr…

Imaging Bacterial Colonies and Phage-Bacterium Interaction at Sub-Nanometer Resolution Using Helium-Ion Microscopy

Imaging of microbial interactions has so far been based on well‐established electron microscopy methods. This study presents a new way to study bacterial colonies and interactions between bacteria and their viruses, bacteriophages (phages), in situ on agar plates using helium ion microscopy (HIM). In biological imaging, HIM has advantages over traditional scanning electron microscopy with its sub‐nanometer resolution, increased surface sensitivity, and the possibility to image nonconductive samples. Furthermore, by controlling the He beam dose or by using heavier Ne ions, the HIM instrument provides the possibility to mill out material in the samples, allowing for subsurface imaging and in …

Resolving Bio–Nano Interactions of E. coli Bacteria–Dragonfly Wing Interface with Helium Ion and 3D-Structured Illumination Microscopy to Understand Bacterial Death on Nanotopography

Obtaining a comprehensive understanding of the bactericidal mechanisms of natural nanotextured surfaces is crucial for the development of fabricated nanotextured surfaces with efficient bactericidal activity. However, the scale, nature, and speed of bacteria-nanotextured surface interactions make the characterization of the interaction a challenging task. There are currently several different opinions regarding the possible mechanisms by which bacterial membrane damage occurs upon interacting with nanotextured surfaces. Advanced imaging methods could clarify this by enabling visualization of the interaction. Charged particle microscopes can achieve the required nanoscale resolution but are …

Chemical characterization and ultrastructure study of pulp fibers

Abstract Understanding the ultrastructure and chemical characterization of pulp fibers is highly important in utilizing wood as a raw material in a wide scope of applications, such as forest biomass-based biorefineries and low-cost renewable materials. The observation of the ultrastructure is not possible without advanced microscopy and spectroscopy techniques. Therefore, this study focuses on exploring the ultrastructure of pulp fibers with helium ion microscopy (HIM) and scanning electron microscopy (SEM). For the analysis of chemical characterization in the pulp fibers, Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) were pe…