scholarly journals A VersaTile-driven platform for rapid hit-to-lead development of engineered lysins

2020 ◽  
Vol 6 (23) ◽  
pp. eaaz1136 ◽  
Author(s):  
H. Gerstmans ◽  
D. Grimon ◽  
D. Gutiérrez ◽  
C. Lood ◽  
A. Rodríguez ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Bacterial Pathogen ◽  
Combinatorial Libraries ◽  
Resistant Bacteria ◽  
Dna Assembly ◽  
Burn Wound ◽  
Development Platform ◽  
High Antibacterial Activity ◽  
Wound Model ◽  
Assembly Method

Health care authorities are calling for new antibacterial therapies to cope with the global emergence of antibiotic-resistant bacteria. Bacteriophage-encoded lysins are a unique class of antibacterials with promising (pre)clinical progress. Custom engineering of lysins allows for the creation of variants against potentially any bacterial pathogen. We here present a high-throughput hit-to-lead development platform for engineered lysins. The platform is driven by VersaTile, a new DNA assembly method for the rapid construction of combinatorial libraries of engineered lysins. We constructed approximately 10,000 lysin variants. Using an iterative screening procedure, we identified a lead variant with high antibacterial activity against Acinetobacter baumannii in human serum and an ex vivo pig burn wound model. This generic platform could offer new opportunities to populate the preclinical pipeline with engineered lysins for diverse (therapeutic) applications.

scholarly journals Active neutrophil responses counteract Candida albicans burn wound infection of ex vivo human skin explants

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Christin von Müller ◽  
Fionnuala Bulman ◽  
Lysett Wagner ◽  
Daniel Rosenberger ◽  
Alessandra Marolda ◽  
...  
Keyword(s):  
Human Skin ◽  
Ex Vivo ◽  
Burn Wound ◽  
Local Immunity ◽  
Fungal Virulence ◽  
Opportunistic Fungi ◽  
Burn Wounds ◽  
Wound Model ◽  
Skin Explants ◽  
Bacteria And Fungi

AbstractBurn wounds are highly susceptible sites for colonization and infection by bacteria and fungi. Large wound surface, impaired local immunity, and broad-spectrum antibiotic therapy support growth of opportunistic fungi such as Candida albicans, which may lead to invasive candidiasis. Currently, it remains unknown whether depressed host defenses or fungal virulence drive the progression of burn wound candidiasis. Here we established an ex vivo burn wound model, where wounds were inflicted by applying preheated soldering iron to human skin explants, resulting in highly reproducible deep second-degree burn wounds. Eschar removal by debridement allowed for deeper C. albicans penetration into the burned tissue associated with prominent filamentation. Active migration of resident tissue neutrophils towards the damaged tissue and release of pro-inflammatory cytokine IL-1β accompanied the burn. The neutrophil recruitment was further increased upon supplementation of the model with fresh immune cells. Wound area and depth decreased over time, indicating healing of the damaged tissue. Importantly, prominent neutrophil presence at the infected site correlated to the limited penetration of C. albicans into the burned tissue. Altogether, we established a reproducible burn wound model of candidiasis using ex vivo human skin explants, where immune responses actively control the progression of infection and promote tissue healing.

scholarly journals Start-Stop Assembly: a functionally scarless DNA assembly system optimised for metabolic engineering

2018 ◽  
Author(s):  
George M. Taylor ◽  
Paweł M. Mordaka ◽  
John T. Heap
Keyword(s):  
Metabolic Engineering ◽  
Design Space ◽  
Combinatorial Libraries ◽  
Dna Assembly ◽  
Destination Vector ◽  
E Coli ◽  
Assembly Method ◽  
Wide Range ◽  
Combinatorial Assembly ◽  
Sequence Boundaries

ABSTRACTDNA assembly allows individual DNA constructs or designed mixtures to be assembled quickly and reliably. Most methods are either: (i) Modular, easily scalable and suitable for combinatorial assembly, but leave undesirable ‘scar’ sequences; or (ii) bespoke (non-modular), scarless but less suitable for construction of combinatorial libraries. Both have limitations for metabolic engineering. To overcome this trade-off we devised Start-Stop Assembly, a multi-part, modular DNA assembly method which is both functionally scarless and suitable for combinatorial assembly. Crucially, 3 bp overhangs corresponding to start and stop codons are used to assemble coding sequences into expression units, avoiding scars at sensitive coding sequence boundaries. Building on this concept, a complete DNA assembly framework was designed and implemented, allowing assembly of up to 15 genes from up to 60 parts (or mixtures); monocistronic, operon-based or hybrid configurations; and a new streamlined assembly hierarchy minimising the number of vectors. Only one destination vector is required per organism, reflecting our optimisation of the system for metabolic engineering in diverse organisms. Metabolic engineering using Start-Stop Assembly was demonstrated by combinatorial assembly of carotenoid pathways inE. coliresulting in a wide range of carotenoid production and colony size phenotypes indicating the intended exploration of design space.GRAPHICAL ABSTRACT

scholarly journals Wound Healing Composite Materials of Bacterial Cellulose and Zinc Oxide Nanoparticles with Immobilized Betulin Diphosphate

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 713
Author(s):  
Nina Melnikova ◽  
Alexander Knyazev ◽  
Viktor Nikolskiy ◽  
Peter Peretyagin ◽  
Kseniia Belyaeva ◽  
...  
Keyword(s):  
Wound Healing ◽  
Zinc Oxide ◽  
Bacterial Cellulose ◽  
Zinc Oxide Nanoparticles ◽  
Wound Dressings ◽  
Oxide Nanoparticles ◽  
Burn Wound ◽  
Zno Nps ◽  
Wound Model ◽  
And Oxidative Stress

A design of new nanocomposites of bacterial cellulose (BC) and betulin diphosphate (BDP) pre-impregnated into the surface of zinc oxide nanoparticles (ZnO NPs) for the production of wound dressings is proposed. The sizes of crystalline BC and ZnO NPs (5–25%) corresponded to 5–6 nm and 10–18 nm, respectively (powder X-ray diffractometry (PXRD), Fourier-infrared (FTIR), ultraviolet (UV), atomic absorption (AAS) and photoluminescence (PL) spectroscopies). The biological activity of the wound dressings “BC-ZnO NPs-BDP” was investigated in rats using a burn wound model. Morpho-histological studies have shown that more intensive healing was observed during treatment with hydrophilic nanocomposites than the oleophilic standard (ZnO NPs-BDP oleogel; p < 0.001). Treatment by both hydrophilic and lipophilic agents led to increases in antioxidant enzyme activity (superoxide dismutase (SOD), catalase) in erythrocytes and decreases in the malondialdehyde (MDA) concentration by 7, 10 and 21 days (p < 0.001). The microcirculation index was restored on the 3rd day after burn under treatment with BC-ZnO NPs-BDP wound dressings. The results of effective wound healing with BC-ZnO NPs-BDP nanocomposites can be explained by the synergistic effect of all nanocomposite components, which regulate oxygenation and microcirculation, reducing hypoxia and oxidative stress in a burn wound.

scholarly journals Effect of bioactive compounds released from Brassicaceae defatted seed meals on bacterial load in pig manure

2021 ◽  
Author(s):  
Luisa Ugolini ◽  
Donatella Scarafile ◽  
Roberto Matteo ◽  
Eleonora Pagnotta ◽  
Lorena Malaguti ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Bacterial Population ◽  
Bacterial Load ◽  
Bacterial Pathogen ◽  
Animal Manure ◽  
Pig Manure ◽  
Resistant Bacteria ◽  
Enzymatic System ◽  
Livestock Waste ◽  
Natural Substances

AbstractAnimal manure application to soils is considered to be one of the main cause of antibiotic and bacterial pathogen spread in the environment. Pig livestock, which is the source of one of the most used fertilizer for cultivated land, is also a hotspot for antibiotics and antibiotic-resistant bacteria. Besides harsh chemical and physical sanitization treatments for the abatement of antibiotics and bacterial load in livestock waste, more sustainable and environmentally friendly strategies need to be considered. In this context, the use of natural substances which are proved useful for pest and disease control is currently under exploration for their role in the reduction of bacterial pathogen population. Among these, plants and derived products from the Brassicaceae family, characterized by the presence of a defensive glucosinolate-myrosinase enzymatic system, have been successfully exploited for years in agriculture using the so-called biofumigation technique against crop diseases. Although the application of biofumigation to suppress a range of soil borne pests has been well documented, no studies have been examined to reduce bacterial population in animal waste. In the present study, the release and the antibacterial activity of bioactive compounds deriving from different Brassicaceae defatted seed meals against pathogens and bacterial population in pig manure is addressed. Rapistrum rugosum and Brassica nigra defatted seed meals were found to be the most active products against tested pathogens and able to significantly reduce the bacterial load in the manure.

scholarly journals Bacteriophages to Control Multi-Drug Resistant Enterococcus faecalis Infection of Dental Root Canals

2021 ◽  
Vol 9 (3) ◽  
pp. 517
Author(s):  
Mohamed El-Telbany ◽  
Gamal El-Didamony ◽  
Ahmed Askora ◽  
Eman Ariny ◽  
Dalia Abdallah ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Root Canal ◽  
Phage Therapy ◽  
Ex Vivo ◽  
Burst Size ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Range Analysis ◽  
Root Canals

Phage therapy is an alternative treatment to antibiotics that can overcome multi-drug resistant bacteria. In this study, we aimed to isolate and characterize lytic bacteriophages targeted against Enterococcus faecalis isolated from root canal infections obtained from clinics at the Faculty of Dentistry, Ismalia, Egypt. Bacteriophage, vB_ZEFP, was isolated from concentrated wastewater collected from hospital sewage. Morphological and genomic analysis revealed that the phage belongs to the Podoviridae family with a linear double-stranded DNA genome, consisting of 18,454, with a G + C content of 32.8%. Host range analysis revealed the phage could infect 10 of 13 E. faecalis isolates exhibiting a range of antibiotic resistances recovered from infected root canals with efficiency of plating values above 0.5. One-step growth curves of this phage showed that it has a burst size of 110 PFU per infected cell, with a latent period of 10 min. The lytic activity of this phage against E. faecalis biofilms showed that the phage was able to control the growth of E. faecalis in vitro. Phage vB_ZEFP could also prevent ex-vivo E. faecalis root canal infection. These results suggest that phage vB_ZEFP has potential for application in phage therapy and specifically in the prevention of infection after root canal treatment.

scholarly journals A Putative Cro-Like Repressor Contributes to Arylomycin Resistance in Staphylococcus aureus

2015 ◽  
Vol 59 (6) ◽  
pp. 3066-3074 ◽  
Author(s):  
Arryn Craney ◽  
Floyd E. Romesberg
Keyword(s):  
Staphylococcus Aureus ◽  
Ex Vivo ◽  
Transcriptional Regulator ◽  
Signal Peptidase ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Type I ◽  
Wall Teichoic Acid ◽  
Content Type ◽  
Wide Range

ABSTRACTAntibiotic-resistant bacteria are a significant public health concern and motivate efforts to develop new classes of antibiotics. One such class of antibiotics is the arylomycins, which target type I signal peptidase (SPase), the enzyme responsible for the release of secreted proteins from their N-terminal leader sequences. Despite the essentiality, conservation, and relative accessibility of SPase, the activity of the arylomycins is limited against some bacteria, including the important human pathogenStaphylococcus aureus. To understand the origins of the limited activity againstS. aureus, we characterized the susceptibility of a panel of strains to two arylomycin derivatives, arylomycin A-C16and its more potent analog arylomycin M131. We observed a wide range of susceptibilities to the two arylomycins and found that resistant strains were sensitized by cotreatment with tunicamycin, which inhibits the first step of wall teichoic acid synthesis. To further understand howS. aureusresponds to the arylomycins, we profiled the transcriptional response ofS. aureusNCTC 8325 to growth-inhibitory concentrations of arylomycin M131 and found that it upregulates the cell wall stress stimulon (CWSS) and an operon consisting of a putative transcriptional regulator and three hypothetical proteins. Interestingly, we found that mutations in the putative transcriptional regulator are correlated with resistance, and selection for resistanceex vivodemonstrated that mutations in this gene are sufficient for resistance. The results begin to elucidate howS. aureuscopes with secretion stress and how it evolves resistance to the inhibition of SPase.

scholarly journals EFFECT OF HEALOL OIL ON WOUND HEALING IN WISTAR RATS: A NOVEL STUDY

2018 ◽  
Vol 11 (3) ◽  
pp. 152
Author(s):  
Sujith V ◽  
Poornima G ◽  
Balaji O ◽  
Bairy Kl ◽  
Praveen K ◽  
...  
Keyword(s):  
Wound Healing ◽  
Wistar Rats ◽  
Chronic Wounds ◽  
Statistical Significance ◽  
Silver Sulfadiazine ◽  
Histopathological Analysis ◽  
Burn Wound ◽  
Excision Wound ◽  
Burn Wounds ◽  
Wound Model

 Objective: Wound healing is a complex process, and various plant extracts have been used to study the effect of medicinal plants on wound healing. Healol oil is used in some tribal areas for ulcer healing and treatment of burn wounds. There are no animal studies done so far using healol oil to find out its role in the treatment of wounds. Hence, the aim of our study is to find the effect of healol oil in excision as well burn wounds in Wistar rats.Methods: Thirty-six Wistar rats were used, 18 rats in excision wound model and remaining in burn wound model. Each model consists of three groups of six rats each. Povidone-iodine was used as a standard control in excision wound model and silver sulfadiazine was used as a standard control in burn wound model. Healol oil was used as test drug in both the models. Period of epithelization and wound contracture rates were analyzed. Histopathological analysis of the skin tissue was done. One-way analysis of variance was used followed by Tukey’s post hoc test for statistical analysis using SPSS version 23 software, P value of <0.05 was taken as statistical significance.Results: Both standard and test groups showed significantly faster wound healing (p<0.001) compared to control rats treated with paraffin wax in both the models. In excision model standard povidone was significantly (p<0.001) better compared to healol oil whereas in burn model, silver sulfadiazine and healol oil showed comparable results with respect to period of epithelization without statistical significance (p>0.05).Conclusion: Wound healing property of healol oil is proved, and further clinical trial can be done to find out the effect of healol oil on chronic wounds due to various etiologies.

scholarly journals Migration of labeled bone marrow MSCs and skin fibroblasts after systemic and local transplantation in rat burn wound model

2015 ◽  
Vol 31 (5) ◽  
pp. 387-394
Author(s):  
E. A. Shchegelskaya ◽  
T. G. Grigorieva ◽  
E. A. Omelchenko ◽  
A. S. Zabirnyk ◽  
E. V. Markelova ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Skin Fibroblasts ◽  
Bone Marrow Mscs ◽  
Burn Wound ◽  
Wound Model
Sign in / Sign up

Export Citation Format

Share Document