respiratory burst
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2022 ◽  
Vol 12 ◽  
Author(s):  
Youcheng Yang ◽  
Jiajun Chen ◽  
Linqing Lu ◽  
Zizheng Xu ◽  
Feng Li ◽  
...  

In the lumen of blood vessels, there are large numbers of erythrocytes, which are approximately 95% of the total blood cells. Although the function of erythrocytes is to transport oxygen in the organism, recent studies have shown that mammalian and teleost erythrocytes are involved in the immune response against bacterial infections. However, the immune mechanisms used by avian erythrocytes are not yet clear. Here, we demonstrated that erythrocytes from goose have the ability to phagocytose as well as conduct antimicrobial activity. Firstly, we revealed the phagocytosis or adhesion activity of goose erythrocytes for latex beads 0.1-1.0 μm in diameter by fluorescence microscopy, and scanning and transmission electron microscopy. The low cytometry results also proved that goose erythrocytes had a wide range of phagocytic or adhesion activity for different bacteria. Followed, the low cytometry analysis data further explored that the goose erythrocytes contain the ability to produce reactive oxygen species (ROS) and inducible nitric oxide synthase (iNOS) in response to bacterial stimulation, and also up-regulated the expression of NOX family includes NOX1 and NOX5. Finally, we also found that goose erythrocytes showed a powerful antibacterial activity against all the three bacteria, meanwhile the stimulation of three kinds of bacteria up-regulated the expression of inflammatory factors, and increased the production of antioxidant enzymes to protect the cells from oxidative damage. Herein, our results demonstrate that goose Erythrocytes possess a certain phagocytic capacity and antioxidant system, and that the antimicrobial activity of erythrocytes can occurred through the production of unique respiratory burst against foreign pathogenic bacteria, which provides new clues to the interaction between bacteria and avian erythrocytes.


2022 ◽  
Vol 12 ◽  
Author(s):  
Xiaojuan Dai ◽  
Huanan Han ◽  
Wei Huang ◽  
Lianghui Zhao ◽  
Minglei Song ◽  
...  

Hybrid breeding of tomatoes (Solanum lycopersicum), an important vegetable crop, is an effective way to improve yield and enhance disease and stress resistance. However, the efficiency of tomato hybridization is hindered by self-fertilization, which can be overcome using male sterile lines. It has been reported that reactive oxygen species (ROS) act as a key regulator for anther development, mediated by RBOH (Respiratory Burst Oxidase Homolog) genes. Here, two tomato anther-expressed genes, LeRBOH (Solyc01g099620) and LeRBOHE (Solyc07g042460), were selected to cultivate novel tomato male sterile strains. By using a CRISPR/Cas9 system with a two-sgRNA module, the lerboh, lerbohe, and lerboh lerbohe mutant lines were generated, among which the lerbohe and lerboh lerbohe mutants displayed complete male sterility but could accept wild-type pollens and produce fruits normally. Further analysis uncovered significantly decreased ROS levels and abnormal programmed cell death in lerboh lerbohe anthers, indicating a key role of ROS metabolism in tomato pollen development. Taken together, our work demonstrates a successful application of gene editing via CRISPR/Cas9 in generating male sterile tomatoes and afforded helpful information for understanding how RBOH genes regulating tomato reproduction process.


2022 ◽  
Vol 23 (2) ◽  
pp. 648
Author(s):  
Yueliang Zhang ◽  
Yiwu Zhang ◽  
Li Luo ◽  
Chunyi Lu ◽  
Weiwen Kong ◽  
...  

Respiratory burst oxidase homologs (Rbohs) are critical enzymes involved in the generation of reactive oxygen species (ROS) that play an important role in plant growth and development as well as various biotic and abiotic stresses in plants. Thus far, there have been few reports on the characterization of the Rboh gene family in Citrus. In this study, seven Rboh genes (CsRbohA~CsRbohG) were identified in the Citrus sinensis genome. The CsRboh proteins were predicted to localize to the cell membrane. Most CsRbohs contained four conserved domains, an EF-hand domain, and a transmembrane region. Phylogenetic analysis demonstrated that the CsRbohs were divided into five groups, suggesting potential distinct functions and evolution. The expression profiles revealed that these seven CsRboh genes displayed tissue-specific expression patterns, and five CsRboh genes were responsive to cold stress. Fourteen putative cis-acting elements related to stress response, hormone response, and development regulation were present within the promoters of CsRboh genes. The in-silico microRNA target transcript analyses indicated that CsRbohE might be targeted by csi-miR164. Further functional and physiological analyses showed that the knockdown of CsRbohD in trifoliate orange impaired resistance to cold stress. As a whole, our results provide valuable information for further functional studies of the CsRboh genes in response to cold stress.


Author(s):  
Dean Kelk ◽  
Jayden Logan ◽  
Isabella Andersen ◽  
Diana Gutierrez Cardenas ◽  
Scott C Bell ◽  
...  

Biomedicine ◽  
2021 ◽  
Vol 41 (4) ◽  
pp. 776-780
Author(s):  
Grisilda Vidya Bernhardt ◽  
Pooja Shivappa ◽  
Manjula Shantaram ◽  
Varsha Jayakar ◽  
Vinayak Lokapur ◽  
...  

Introduction and Aim: Diabetic foot ulcers are common complications seen in diabetic patients. Treatment of this  disabling foot sore remains a challenge to health care professionals. This study aimed at evaluating whether the neutrophils from type 2 diabetic patients with foot ulcers present an impairment of phagocytic index and impairment in respiratory burst. We also aimed at understanding whether the impairment in neutrophil phagocytic activity can be alleviated with short course of standard treatment regime for foot ulcers.   Methodology: For this case-controled study, 43 participants  with type 2 diabetes  (18  with foot ulcers and 25 without foot ulcers) were prospectively recruited along with 18 healthy volunteers. Phagocytic activity of neutrophils and respiratory burst of neutrophils was assessed  along with ESR, percentage neutrophil counts before and after 2 weeks of standard treatment for foot ulcers.   Results: Neutrophils of type 2 diabetic patients (with and without foot ulcers ) showed  lower levels of phagocytic index and lower percentage of respiratory burst  on  comparison with non-diabetic subjects. Furthermore, on receiving treatment for foot ulcers, a significant improvement in neutrophil phagocytic indices were observed, along with improvement in wound ulcer score.   Conclusion: Phagocytic activity of the neutrophils is impaired  in  type 2 diabetics (with and without foot ulcers). Neutrophil phagocytic indices can be improved on glycemic control. Additionally, improvement in neutrophil phagocytic indices after short course treatment for foot ulcers can be useful markers to predict treatment efficacy and in prognosis of diabetic foot ulcers.


2021 ◽  
Vol 119 ◽  
pp. 96-104
Author(s):  
Zizheng Xu ◽  
Youcheng Yang ◽  
V. Sarath Babu ◽  
Jiajun Chen ◽  
Feng Li ◽  
...  

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Hyo In Kim ◽  
Jinbong Park ◽  
Barbora Konecna ◽  
Wei Huang ◽  
Ingred Riça ◽  
...  

2021 ◽  
Author(s):  
◽  
Blake William Paget

<p>Cattle are constantly exposed to environmental pathogens and are susceptible to a number of diseases which cause significant economic loss or animal welfare concerns. The mucosal surface is a key barrier to infection and a greater understanding of bovine mucosal immunology may lead to improved disease management strategies. The cathelicidins are a family of host defence proteins which may play an important role in this defensive barrier.  The cathelicidins are composed of a globular cathelin-like domain (CLD) and a C-terminal antimicrobial peptide (AMP) domain. The CLD is highly conserved across all species in which cathelicidins are found, yet the role of the CLD during infection has not been firmly established. The first aim of this thesis was to produce functional recombinant bovine CLD as a precursor to further experiments. However, the recombinant protein bound less lipopolysaccharide, was unable to agglutinate microbes, and was unable to permeabilise neutrophil membranes when compared to the activity of a native CLD preparation. Although further studies were not carried out with recombinant CLD, these results demonstrated that cell death induced by the native CLD and the agglutination of microbes potentially contribute to a broad anti-inflammatory role for the CLD during infection.  In contrast to humans and mice where only one cathelicidin isoform is expressed, bovine express seven cathelicidins, with variable AMP domains. Therefore the second aim of this thesis was to profile the effect of bovine cathelicidin AMPs on neutrophil function. The bovine AMPs were able to modify a number of activities. Migration and reactive oxygen species (ROS) production were enhanced by several peptides while ROS production was inhibited by others. When investigated in further detail, linear Bac1 (bactenecin), Bac5 and BMAP-34 (bovine myeloid antimicrobial peptide) were able to dose-dependently induce or inhibit several key neutrophil functions including migration, degranulation, respiratory burst and phagocytosis, indicating significant roles in differential modulation of immune responses. In particular, Bac5 was able to differentially modify neutrophil respiratory burst without significant disruption to cellular homeostasis, which suggested Bac5 was acting via an intracellular mechanism.  The third aim of this thesis was to investigate the mechanism by which Bac5 modulated neutrophil function. The results demonstrated the ability of Bac5 to be internalised by neutrophils and that Bac5 inhibition of p47phox binding to nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is a possible explanation for the differential induction and inhibition of extracellular ROS production. β-actin was identified as a major intracellular target for Bac5 and is consistent with the ability of Bac5 to modulate multiple neutrophil functions.  In summary, this thesis demonstrates that the bovine cathelicidins have multiple roles in host defence. The conserved CLD appears to have an anti-inflammatory role through an as yet undefined mechanism. The variable AMPs together have multifaceted roles which may act in concert to promote elimination of pathogens and regulate excessive detrimental neutrophil activity. The combined effect of these roles will facilitate clearance of pathogens during infection and aid in the resolution of the innate inflammatory response at mucosal surfaces.</p>


2021 ◽  
Author(s):  
◽  
Blake William Paget

<p>Cattle are constantly exposed to environmental pathogens and are susceptible to a number of diseases which cause significant economic loss or animal welfare concerns. The mucosal surface is a key barrier to infection and a greater understanding of bovine mucosal immunology may lead to improved disease management strategies. The cathelicidins are a family of host defence proteins which may play an important role in this defensive barrier.  The cathelicidins are composed of a globular cathelin-like domain (CLD) and a C-terminal antimicrobial peptide (AMP) domain. The CLD is highly conserved across all species in which cathelicidins are found, yet the role of the CLD during infection has not been firmly established. The first aim of this thesis was to produce functional recombinant bovine CLD as a precursor to further experiments. However, the recombinant protein bound less lipopolysaccharide, was unable to agglutinate microbes, and was unable to permeabilise neutrophil membranes when compared to the activity of a native CLD preparation. Although further studies were not carried out with recombinant CLD, these results demonstrated that cell death induced by the native CLD and the agglutination of microbes potentially contribute to a broad anti-inflammatory role for the CLD during infection.  In contrast to humans and mice where only one cathelicidin isoform is expressed, bovine express seven cathelicidins, with variable AMP domains. Therefore the second aim of this thesis was to profile the effect of bovine cathelicidin AMPs on neutrophil function. The bovine AMPs were able to modify a number of activities. Migration and reactive oxygen species (ROS) production were enhanced by several peptides while ROS production was inhibited by others. When investigated in further detail, linear Bac1 (bactenecin), Bac5 and BMAP-34 (bovine myeloid antimicrobial peptide) were able to dose-dependently induce or inhibit several key neutrophil functions including migration, degranulation, respiratory burst and phagocytosis, indicating significant roles in differential modulation of immune responses. In particular, Bac5 was able to differentially modify neutrophil respiratory burst without significant disruption to cellular homeostasis, which suggested Bac5 was acting via an intracellular mechanism.  The third aim of this thesis was to investigate the mechanism by which Bac5 modulated neutrophil function. The results demonstrated the ability of Bac5 to be internalised by neutrophils and that Bac5 inhibition of p47phox binding to nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is a possible explanation for the differential induction and inhibition of extracellular ROS production. β-actin was identified as a major intracellular target for Bac5 and is consistent with the ability of Bac5 to modulate multiple neutrophil functions.  In summary, this thesis demonstrates that the bovine cathelicidins have multiple roles in host defence. The conserved CLD appears to have an anti-inflammatory role through an as yet undefined mechanism. The variable AMPs together have multifaceted roles which may act in concert to promote elimination of pathogens and regulate excessive detrimental neutrophil activity. The combined effect of these roles will facilitate clearance of pathogens during infection and aid in the resolution of the innate inflammatory response at mucosal surfaces.</p>


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