Assembly of Bacterial Capsular Polysaccharides and Exopolysaccharides

2020 ◽  
Vol 74 (1) ◽  
pp. 521-543 ◽  
Author(s):  
Chris Whitfield ◽  
Samantha S. Wear ◽  
Caitlin Sande
Keyword(s):  
Structural Biology ◽  
Biomedical Applications ◽  
Capsular Polysaccharide ◽  
Strong Association ◽  
Capsular Polysaccharides ◽  
Physical Chemical ◽  
Wide Range ◽  
Bacterial Surfaces ◽  
Genomic Studies ◽  
Long Chain

Polysaccharides are dominant features of most bacterial surfaces and are displayed in different formats. Many bacteria produce abundant long-chain capsular polysaccharides, which can maintain a strong association and form a capsule structure enveloping the cell and/or take the form of exopolysaccharides that are mostly secreted into the immediate environment. These polymers afford the producing bacteria protection from a wide range of physical, chemical, and biological stresses, support biofilms, and play critical roles in interactions between bacteria and their immediate environments. Their biological and physical properties also drive a variety of industrial and biomedical applications. Despite the immense variation in capsular polysaccharide and exopolysaccharide structures, patterns are evident in strategies used for their assembly and export. This review describes recent advances in understanding those strategies, based on a wealth of biochemical investigations of select prototypes, supported by complementary insight from expanding structural biology initiatives. This provides a framework to identify and distinguish new systems emanating from genomic studies.

scholarly journals Development of a universal nanobody-binding Fab module for fiducial-assisted cryo-EM studies of membrane proteins

2021 ◽  
Vol 118 (47) ◽  
pp. e2115435118
Author(s):  
Joël S. Bloch ◽  
Somnath Mukherjee ◽  
Julia Kowal ◽  
Ekaterina V. Filippova ◽  
Martina Niederer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Membrane Proteins ◽  
Structural Biology ◽  
Biomedical Applications ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Antigen Binding ◽  
Biological Applications ◽  
Wide Range ◽  
Grafting Onto

With conformation-specific nanobodies being used for a wide range of structural, biochemical, and cell biological applications, there is a demand for antigen-binding fragments (Fabs) that specifically and tightly bind these nanobodies without disturbing the nanobody–target protein interaction. Here, we describe the development of a synthetic Fab (termed NabFab) that binds the scaffold of an alpaca-derived nanobody with picomolar affinity. We demonstrate that upon complementary-determining region grafting onto this parent nanobody scaffold, nanobodies recognizing diverse target proteins and derived from llama or camel can cross-react with NabFab without loss of affinity. Using NabFab as a fiducial and size enhancer (50 kDa), we determined the high-resolution cryogenic electron microscopy (cryo-EM) structures of nanobody-bound VcNorM and ScaDMT, both small membrane proteins of ∼50 kDa. Using an additional anti-Fab nanobody further facilitated reliable initial three-dimensional structure determination from small cryo-EM test datasets. Given that NabFab is of synthetic origin, is humanized, and can be conveniently expressed in Escherichia coli in large amounts, it may be useful not only for structural biology but also for biomedical applications.

scholarly journals Development of a universal nanobody-binding Fab module for fiducial-assisted cryo-EM studies of membrane proteins

2021 ◽  
Author(s):  
Joël S. Bloch ◽  
Somnath Mukherjee ◽  
Julia Kowal ◽  
Ekaterina V. Filippova ◽  
Martina Niederer ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Structural Biology ◽  
Biomedical Applications ◽  
3D Structure ◽  
Antigen Binding ◽  
Biological Applications ◽  
E Coli ◽  
Wide Range ◽  
Cdr Grafting ◽  
3D Structure Determination

AbstractWith conformation-specific nanobodies being used for a wide range of structural, biochemical, and cell biological applications, there is a demand for antigen-binding fragments (Fabs) that specifically and tightly bind these nanobodies without disturbing the nanobody-target protein interaction. Here we describe the development of a synthetic Fab (termed NabFab) that binds the scaffold of an alpaca-derived nanobody with picomolar affinity. We demonstrate that upon CDR grafting onto this parent nanobody scaffold, nanobodies recognizing diverse target proteins and derived from llama or camel can cross-react with NabFab without loss of affinity. Using NabFab as a fiducial and size enhancer (50 kDa), we determined the high-resolution cryo-EM structures of nanobody-bound VcNorM and ScaDMT, both small membrane proteins of ~50 kDa. Using an additional anti-Fab nanobody further facillitated reliable initial 3D structure determination from small cryo-EM test datasets. Given that NabFab is of synthetic origin, humanized, and can be conveniently expressed in E. coli in large amounts, it may not only be useful for structural biology, but also for biomedical applications.

Strong Association between Serotonin Transporter 5-HTTVNTR Variant and Psychoactive Substance (Nicotine) Use in the Turkish Cypriot Population

2020 ◽  
Vol 21 (6) ◽  
pp. 466-470
Author(s):  
Emine Kandemis ◽  
Gulten Tuncel ◽  
Ozen Asut ◽  
Sehime G. Temel ◽  
Mahmut C. Ergoren
Keyword(s):  
Serotonin Transporter ◽  
Association Studies ◽  
Strong Association ◽  
Smoking Behavior ◽  
Population Based ◽  
Genome Wide Association Studies ◽  
Genotype Distribution ◽  
Psychological Traits ◽  
Wide Range ◽  
Turkish Cypriot

Background: The use of psychoactive substances is one of the most dangerous social problems worldwide. Nicotine dependence results from the interaction between neurobiological, environmental and genetic factors. Serotonin is a neurotransmitter that has a wide range of central nervous system activities. The serotonin transporter gene has been previously linked to psychological traits. Objective: A variable number of tandem repeats within the serotonin transporter-linked polymorphic gene region are believed to alter the transcriptional efficiency of the 5-HTT gene. Therefore, we aimed to investigate the association between this polymorphic site and smoking behavior in the Turkish Cypriot population. Methods: A total of 259 (100 smokers, 100 non-smokers and 59 ex-smokers) Turkish Cypriots were included in this population-based cross-sectional study. Genomic DNA was extracted from peripheral blood samples and the 5-HTTVNTR2 polymorphisms were determined by the PCR-RFLP. Results: The allelic frequency and genotype distribution results of this study showed a strong association (P<0.0001) between smokers and non-smokers. No statistical significance was found between non-smokers and ex-smokers. Conclusion: This is the first genetic epidemiology study to investigate the allelic frequencies of 5-HTTVNTR2 polymorphisms associated with smoking behavior in the Turkish Cypriot population. Based on the results of this study, genome-wide association studies should be designed for preventive medicine in this population.

scholarly journals Recent trends in smartphone-based detection for biomedical applications: a review

2021 ◽  
Vol 413 (9) ◽  
pp. 2389-2406 ◽  
Author(s):  
Soumyabrata Banik ◽  
Sindhoora Kaniyala Melanthota ◽  
Arbaaz ◽  
Joel Markus Vaz ◽  
Vishak Madhwaraj Kadambalithaya ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Histopathological Examination ◽  
Dark Field ◽  
Portable Devices ◽  
Food Technology ◽  
Wide Range ◽  
Technological Interventions ◽  
Recent Trends ◽  
Increasing Demand

AbstractSmartphone-based imaging devices (SIDs) have shown to be versatile and have a wide range of biomedical applications. With the increasing demand for high-quality medical services, technological interventions such as portable devices that can be used in remote and resource-less conditions and have an impact on quantity and quality of care. Additionally, smartphone-based devices have shown their application in the field of teleimaging, food technology, education, etc. Depending on the application and imaging capability required, the optical arrangement of the SID varies which enables them to be used in multiple setups like bright-field, fluorescence, dark-field, and multiple arrays with certain changes in their optics and illumination. This comprehensive review discusses the numerous applications and development of SIDs towards histopathological examination, detection of bacteria and viruses, food technology, and routine diagnosis. Smartphone-based devices are complemented with deep learning methods to further increase the efficiency of the devices.

scholarly journals Burkholderia thailandensis E264 as a promising safe rhamnolipids’ producer towards a sustainable valorization of grape marcs and olive mill pomace

2021 ◽  
Author(s):  
Alif Chebbi ◽  
Massimiliano Tazzari ◽  
Cristiana Rizzi ◽  
Franco Hernan Gomez Tovar ◽  
Sara Villa ◽  
...  
Keyword(s):  
Energy Source ◽  
Olive Oil ◽  
Low Cost ◽  
Carbon Sources ◽  
Burkholderia Thailandensis ◽  
Rhamnolipid Production ◽  
Key Points ◽  
Wide Range ◽  
Long Chain ◽  
Olive Mill

Abstract Within the circular economy framework, our study aims to assess the rhamnolipid production from winery and olive oil residues as low-cost carbon sources by nonpathogenic strains. After evaluating various agricultural residues from those two sectors, Burkholderia thailandensis E264 was found to use the raw soluble fraction of nonfermented (white) grape marcs (NF), as the sole carbon and energy source, and simultaneously, reducing the surface tension to around 35 mN/m. Interestingly, this strain showed a rhamnolipid production up to 1070 mg/L (13.37 mg/g of NF), with a higher purity, on those grape marcs, predominately Rha-Rha C14-C14, in MSM medium. On olive oil residues, the rhamnolipid yield of using olive mill pomace (OMP) at 2% (w/v) was around 300 mg/L (15 mg/g of OMP) with a similar CMC of 500 mg/L. To the best of our knowledge, our study indicated for the first time that a nonpathogenic bacterium is able to produce long-chain rhamnolipids in MSM medium supplemented with winery residues, as sole carbon and energy source. Key points • Winery and olive oil residues are used for producing long-chain rhamnolipids (RLs). • Both higher RL yields and purity were obtained on nonfermented grape marcs as substrates. • Long-chain RLs revealed stabilities over a wide range of pH, temperatures, and salinities

Recent advances in the design of inorganic and nano-clay particles for the treatment of brain disorders

2021 ◽  
Author(s):  
Francesca Persano ◽  
Svetlana Batasheva ◽  
Gölnur Fakhrullina ◽  
Giuseppe Gigli ◽  
Stefano Leporatti ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Silica Nanoparticles ◽  
Biomedical Applications ◽  
Inorganic Materials ◽  
Brain Disorders ◽  
Clay Particles ◽  
Recent Advances ◽  
Wide Range ◽  
Nano Clay

Inorganic materials, in particular nanoclays and silica nanoparticles, have attracted enormous attention due to their versatile and tuneable properties, making them ideal candidates for a wide range of biomedical applications, such as drug delivery.

scholarly journals Two-photon polymerization nanolithography technology for fabrication of stimulus-responsive micro/nano-structures for biomedical applications

2020 ◽  
Vol 9 (1) ◽  
pp. 1118-1136
Author(s):  
Zhenjia Huang ◽  
Gary Chi-Pong Tsui ◽  
Yu Deng ◽  
Chak-Yin Tang
Keyword(s):  
Biomedical Applications ◽  
Three Dimensional ◽  
Water Soluble ◽  
Fabrication Technology ◽  
Nano Fabrication ◽  
Two Photon ◽  
Nano Structures ◽  
Wide Range ◽  
Stimulus Responsive ◽  
Two Photon Polymerization

AbstractMicro/nano-fabrication technology via two-photon polymerization (TPP) nanolithography is a powerful and useful manufacturing tool that is capable of generating two dimensional (2D) to three dimensional (3D) arbitrary micro/nano-structures of various materials with a high spatial resolution. This technology has received tremendous interest in cell and tissue engineering and medical microdevices because of its remarkable fabrication capability for sophisticated structures from macro- to nano-scale, which are difficult to be achieved by traditional methods with limited microarchitecture controllability. To fabricate precisely designed 3D micro/nano-structures for biomedical applications via TPP nanolithography, the use of photoinitiators (PIs) and photoresists needs to be considered comprehensively and systematically. In this review, widely used commercially available PIs are first discussed, followed by elucidating synthesis strategies of water-soluble initiators for biomedical applications. In addition to the conventional photoresists, the distinctive properties of customized stimulus-responsive photoresists are discussed. Finally, current limitations and challenges in the material and fabrication aspects and an outlook for future prospects of TPP for biomedical applications based on different biocompatible photosensitive composites are discussed comprehensively. In all, this review provides a basic understanding of TPP technology and important roles of PIs and photoresists for fabricating high-precision stimulus-responsive micro/nano-structures for a wide range of biomedical applications.

scholarly journals Preparation of Silver Nanoparticles and Their Industrial and Biomedical Applications: A Comprehensive Review

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Adnan Haider ◽  
Inn-Kyu Kang
Keyword(s):  
Silver Nanoparticles ◽  
Biomedical Applications ◽  
Consumer Products ◽  
Ag Nps ◽  
New Techniques ◽  
Governing Factor ◽  
Wide Range ◽  
Microbial Proliferation ◽  
Synthetic Routes ◽  
Biomedical Fields

Silver nanoparticles (Ag-NPs) have diverted the attention of the scientific community and industrialist itself due to their wide range of applications in industry for the preparation of consumer products and highly accepted application in biomedical fields (especially their efficacy against microbes, anti-inflammatory effects, and wound healing ability). The governing factor for their potent efficacy against microbes is considered to be the various mechanisms enabling it to prevent microbial proliferation and their infections. Furthermore a number of new techniques have been developed to synthesize Ag-NPs with controlled size and geometry. In this review, various synthetic routes adapted for the preparation of the Ag-NPs, the mechanisms involved in its antimicrobial activity, its importance/application in commercial as well as biomedical fields, and possible application in future have been discussed in detail.

scholarly journals From Residues to Added-Value Bacterial Biopolymers as Nanomaterials for Biomedical Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1492
Author(s):  
Francisco G. Blanco ◽  
Natalia Hernández ◽  
Virginia Rivero-Buceta ◽  
Beatriz Maestro ◽  
Jesús M. Sanz ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Carbon Sources ◽  
Structural Diversity ◽  
Added Value ◽  
Nanoscale Systems ◽  
Chemical Structures ◽  
Wide Range ◽  
Peptide Functionalization ◽  
Metabolic Strategies ◽  
Drug Nanocarriers

Bacterial biopolymers are naturally occurring materials comprising a wide range of molecules with diverse chemical structures that can be produced from renewable sources following the principles of the circular economy. Over the last decades, they have gained substantial interest in the biomedical field as drug nanocarriers, implantable material coatings, and tissue-regeneration scaffolds or membranes due to their inherent biocompatibility, biodegradability into nonhazardous disintegration products, and their mechanical properties, which are similar to those of human tissues. The present review focuses upon three technologically advanced bacterial biopolymers, namely, bacterial cellulose (BC), polyhydroxyalkanoates (PHA), and γ-polyglutamic acid (PGA), as models of different carbon-backbone structures (polysaccharides, polyesters, and polyamides) produced by bacteria that are suitable for biomedical applications in nanoscale systems. This selection models evidence of the wide versatility of microorganisms to generate biopolymers by diverse metabolic strategies. We highlight the suitability for applied sustainable bioprocesses for the production of BC, PHA, and PGA based on renewable carbon sources and the singularity of each process driven by bacterial machinery. The inherent properties of each polymer can be fine-tuned by means of chemical and biotechnological approaches, such as metabolic engineering and peptide functionalization, to further expand their structural diversity and their applicability as nanomaterials in biomedicine.

Femtosecond laser structuring of permeable and resorbable biomaterial

2021 ◽  
Vol 7 (2) ◽  
pp. 713-716
Author(s):  
Swen Grossmann ◽  
Sabine Illner ◽  
Robert Ott ◽  
Grit Rhinow ◽  
Carsten Tautorat ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Biomedical Applications ◽  
Mechanical Characteristics ◽  
Membrane Properties ◽  
Fiber Network ◽  
Laser Technology ◽  
Laser Structuring ◽  
Wide Range ◽  
Nanofiber Membranes ◽  
Post Production

Abstract Bioresorbable nanofiber nonwovens with their fascinating properties provide a wide range of potential biomedical applications. Modification of the material enables the adjustment of mechanical and biological characteristics depending on the desired application. Due to the nanosized fiber network, post-production structuring is very challenging. Within this study, we use femtosecond laser technology for structuring permeable and resorbable electrospun poly-L-lactide (PLLA) membranes. We show that this post-production process can be used without disturbing the fiber network near the structured areas. Furthermore, the modification of the water permeability and mechanical characteristics due to the laser structuring was investigated. The results prove femtosecond laser technology to be a promising method for the adjustment of the membrane properties and which in consequence can help to optimize cell adhesion, enable revascularization and open up applications of nanofiber membranes in personalized medicine.

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