Respiratory Burst Research Articles

EpiFusion: Joint inference of the effective reproduction number by integrating phylodynamic and epidemiological modelling with particle filtering.

Accurately estimating the effective reproduction number (Rt) of a circulating pathogen is a fundamental challenge in the study of infectious disease. The fields of epidemiology and pathogen phylodynamics both share this goal, but to date, methodologies and data employed by each remain largely distinct. Here we present EpiFusion: a joint approach that can be used to harness the complementary strengths of each field to improve estimation of outbreak dynamics for large and poorly sampled epidemics, such as arboviral or respiratory virus outbreaks, and validate it for retrospective analysis. We propose a model of Rt that estimates outbreak trajectories conditional upon both phylodynamic (time-scaled trees estimated from genetic sequences) and epidemiological (case incidence) data. We simulate stochastic outbreak trajectories that are weighted according to epidemiological and phylodynamic observation models and fit using particle Markov Chain Monte Carlo. To assess performance, we test EpiFusion on simulated outbreaks in which transmission and/or surveillance rapidly changes and find that using EpiFusion to combine epidemiological and phylodynamic data maintains accuracy and increases certainty in trajectory and Rt estimates, compared to when each data type is used alone. We benchmark EpiFusion's performance against existing methods to estimate Rt and demonstrate advances in speed and accuracy. Importantly, our approach scales efficiently with dataset size. Finally, we apply our model to estimate Rt during the 2014 Ebola outbreak in Sierra Leone. EpiFusion is designed to accommodate future extensions that will improve its utility, such as explicitly modelling population structure, accommodations for phylogenetic uncertainty, and the ability to weight the contributions of genomic or case incidence to the inference.

Transcription factor PagWRKY33 regulates gibberellin signaling and immune receptor pathways in Populus.

Enhanced autoimmunity often leads to impaired plant growth and development, and the coordination of immunity and growth in Populus remains elusive. In this study, we have identified the transcription factors PagWRKY33a/b as key regulators of immune response and growth maintenance in Populus. The disruption of PagWRKY33a/b causes growth issues and autoimmunity while conferring resistance to anthracnose caused by Colletotrichum gloeosporioides. PagWRKY33a/b binds to the promoters of N requirement gene 1.1 (NRG1.1) and Gibberellic Acid-Stimulated in Arabidopsis (GASA14)during infection, activating their transcription. This process maintains disease resistance and engages in GA signaling to reduce growth costs from immune activation. The oxPagWRKY33a/nrg1.1 mutant results in reduced resistance to C. gloeosporioides. Further, PagWRKY33a/b is phosphorylated and activated by Mitogen-Activated Protein Kinase Kinase 1 (MKK1), which inhibits Respiratory Burst Oxidase Homolog D (RBOHD) and Respiratory Burst Oxidase Homolog I (RBOHI) transcription, causing ROS bursts in wrky33a/b double mutants. This leads to an upregulation of PagNRG1.1 in the absence of pathogens. However, the wrky33a/b/nrg1.1 and wrky33a/b/rbohd triple mutants show compromised defense responses, underscoring the complexity of WRKY33 regulation. Additionally, the stability of PagWRKY33 is modulated by Ring Finger Protein 5 (PagRNF5)-mediated ubiquitination, balancing plant immunity and growth. Together, our results provide key insights into the complex function of WRKY33 in Populus autoimmunity and its impact on growth and development.

Advance in Nrf2 Signaling Pathway in Leishmaniasis

One of the main components of innate defense against invasive parasites is oxidative stress, which is brought on by reactive oxygen species (ROS). On the other hand, oxidative stressors serve two purposes: free radicals aid in the elimination of pathogens, but they can also set off inflammation, which leads to tissue damage. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that controls the expression of numerous genes involved in the body’s defense against oxidative stress brought on by aging, inflammation, tissue damage, and other pathological consequences. From cutaneous to visceral forms, Leishmania parasites invade macrophages and cause a wide range of human pathologies. Leishmania parasites have a wide range of adaptive mechanisms that disrupt several macrophage functions by altering host signaling pathways. An increasing amount of data are corroborating the idea that one of the primary antioxidant routes to counteract this oxidative burst against parasites is NRF2 signaling, which also interferes with immune responses. The nature and potency of the host immune response, as well as interactions between the invading Leishmania spp., will ascertain the course of infection and the parasites’ eventual survival or eradication. The molecular processes via which Nrf2 coordinates such intricate networks comprising various pathways remain to be completely understood. In light of NRF2’s significant contribution to oxidative stress, we examine the NRF2 antioxidant pathway’s activation mechanism in Leishmania infection in this review. Thus, this review will examine the relationship between Nrf2 signaling and leishmaniasis, as well as explore potential therapeutic strategies for modifying this system.

SYNLAC prime probiotics enhances growth performance, and resistance of white shrimp, Penaeus vannamei to Enterocytozoon hepatopenaei and Vibrio alginollyticus: insights into immune and metabolic pathway modulations

This study explores the impact of SYNLAC Prime probiotics on the growth performance, health status, and metabolic profile of white shrimp, Penaeus vannamei. Shrimp fed with the experimental diets, including the control diet without probiotic supplementation, and the diets supplemented with SYNLAC Prime probiotics at concentrations of 105 CFU (g diet)-1 (P5) and 106 CFU (g diet)-1 (P6) for 56 days. Results indicated a significant enhancement in growth performance in probiotic-treated shrimp relative to the control group, attributed to structural improvements in the digestive tract, particularly the increased abundances of B cells in the hepatopancreas. The administration of dietary probiotics markedly reduced the severity of Enterocytozoon hepatopenaei (EHP) infection and decreased cumulative mortalities following Vibrio alginolyticus challenge. Shrimp in the P6 group exhibited significant elevations in phenoloxidase activity, respiratory burst, lysozyme activity and phagocytic activity compared to control group. Furthermore, there was an upregulation of several immune-related genes in hepatopancreas, including serine protease (SP), prophenoloxidase (proPO) I, proPO II, and penaeidin 3a. Additionally, the expression of β-1, 3-glucan binding protein and SP mRNA was significantly increased in hemocytes. Untargeted metabolomics analysis using LC-MS/MS revealed significant changes in the hepatopancreas metabolic profile, highlighting alterations in energy metabolisms pathways, such as citrate cycle and nicotinate and nicotinamide metabolism, as well as amino acid metabolisms pathways including arginine and proline metabolism, taurine and hypotaurine metabolism, and histidine metabolism. These findings underscore the potential of SYNLAC Prime probiotics in enhancing shrimp growth, immune function, and metabolic pathways, offering valuable insights for advancing health management strategies in shrimp aquaculture.

Respiratory Disease Surveillance in the Middle East and Latin America during the COVID-19 Pandemic, 2020-2022.

Characterizing the epidemiology of circulating respiratory pathogens during the COVID-19 pandemic could clarify the burden of acute respiratory infections and monitor outbreaks of public health and military relevance. The US Department of Defense supported 2 regions for influenza-like illness and severe acute respiratory infections surveillance, one in the Middle East through US Naval Medical Research Unit EURAFCENT, and another in Latin America through US Naval Medical Research Unit SOUTH. During 2020‒2022, coinciding with the COVID-19 pandemic, we collected a total of 16,146 nasopharyngeal and oropharyngeal swab samples from sentinel sites in Jordan (n = 11,305) and Latin America (n = 4,841). Samples were tested for SARS-CoV-2, influenza, and other respiratory pathogens. SARS-CoV-2 was the most frequently detected pathogen during 2020; other respiratory pathogens had distinct temporal and frequency distributions according to geographic location. Our findings support the need for continued sentinel surveillance as a vital tool for assessing the burden of respiratory diseases globally.

Comparative transcriptome analysis of tobacco plants reveals differences in reactive oxygen species activated defenses following the infestations of non-viruliferous and TYLCCNV-viruliferous whitefly Mediterranean

ABSTRACT Tomato yellow leaf curl China virus (TYLCCNV) viruliferous Mediterranean (MED) whitefly infestation in tobacco plants elevated hydrogen peroxide (H2O2) levels more than non-viruliferous ones. To unravel the underlying mechanisms behind the phenomenon, comparative analyses of plant transcriptome and enzyme activities of reactive oxygen species (ROS) scavengers were conducted in this study. Compared to the control, a total of 4032 and 6853 differentially expressed genes (DEGs) were identified in the plants following the infestations of non-viruliferous and TYLCCNV-viruliferous MED, respectively. Gene ontology analysis of DEGs suggested substantial transcriptional reprogramming of diverse cellular processes, particularly in the biotic stress response pathways of tobacco plants. Respiratory burst oxidase homologs related genes and important kinases putatively involved in plant defense were differentially modulated in tobacco plants in response to the non-viruliferous and TYLCCNV-viruliferous whitefly MED infestation. The analysis reported here lays out a strong foundation for future investigations into the mechanisms of ROS-associated plant defense mediating the interactions between B. tabaci and begomoviruses.

Neutrophil Migration is a Crucial Factor in Wound Healing and the Pathogenesis of Diabetic Foot Ulcers: Insights into Pharmacological Interventions.

Diabetic foot ulcers (DFUs) pose a significant clinical challenge, characterized by impaired wound healing, chronic inflammation, and increased risk of infection. Neutrophils, as critical components of the innate immune response, play a pivotal role in the initial stages of wound healing, particularly during the inflammatory phase. This review explores the intricate relationship between neutrophil migration, inflammation, and the pathogenesis of DFU and drugs that can impact neutrophil production and migration. Neutrophils contribute to infection control through phagocytosis and release pro-inflammatory cytokines and reactive oxygen species, which, when dysregulated, can impede the wound healing process. Furthermore, the chronic hyperglycemic state characteristic of diabetes mellitus has been implicated in impairing neutrophil functions, including chemotaxis and oxidative burst. This compromised neutrophil response prolongs the inflammatory phase and disrupts the delicate balance required for efficient wound healing. Neutrophil extracellular traps (NETs), a unique form of neutrophil defence, have also been implicated in DFU pathogenesis, potentially exacerbating inflammation and tissue damage. Understanding the intricate interplay between neutrophil migration, dysregulated inflammatory responses, and hyperglycemia-driven impairments is essential for developing targeted therapeutic strategies for DFUs. This review sheds light on the critical role of neutrophils in DFU pathogenesis, and innovative and advanced treatment strategies for DFU, highlighting the potential for novel interventions to restore the balance between pro-inflammatory and wound healing processes, ultimately improving clinical outcomes for individuals with DFU.

A novel root hair mutant, srh1, affects root hair elongation and reactive oxygen species levels in wheat.

Root hairs are single-celled projections on root surfaces, critical for water and nutrient uptake. Here, we describe the first short root hair mutant in wheat (Triticum aestivum L.), identified in a mutagenized population and termed here short root hair 1 (srh1). While the srh1 mutant can initiate root hair bulges, lack of subsequent extension results in very short root hairs. Due to its semi-dominant nature, heterozygous lines displayed intermediate root hair lengths compared to wild-type. Bulked segregant analysis in a BC1F3 segregating population genotyped via exome capture sequencing localized the genetic control of this mutant to a region on the long arm of chromosome 3A. Via RNA sequencing and bioinformatic analysis, we identified two promising candidate genes. The first was a respiratory burst oxidase homolog (RBOH) encoding gene TaNOX3-A, orthologous to RBOH genes controlling root hair elongation in rice (OsNOX3) and maize (ZmRTH5), that carries a missense mutation in a conserved region of the predicted protein. RBOHs are membrane bound proteins that produce reactive oxygen species (ROS) which trigger cell wall extensibility, allowing subsequent root hair elongation. Notably, reduced ROS levels were observed in srh1 root hair bulges compared to wild-type. The second candidate was the calreticulin-3 encoding gene TaCRT3-A, located within the wider srh1 interval and whose expression was significantly downregulated in srh1 root tissues. The identification of a major effect gene controlling wheat root hair morphology provides an entry point for future optimization of root hair architecture best suited to future agricultural environments.

Orchestrating ROS regulation: coordinated post-translational modification switches in NADPH oxidases.

Reactive oxygen species (ROS) are among the most important signaling molecules, playing a significant role in plant growth, development, and responses to various environmental stresses. Respiratory burst oxidase homologs (RBOHs) are key enzymes in ROS production. Plants tightly regulate the activation and deactivation of RBOHs through various post-translational modifications (PTMs), including phosphorylation, ubiquitination, S-nitrosylation, and persulfidation. These PTMs fine-tune ROS production, ensuring normal plant growth and development while facilitating rapid responses to abiotic and biotic stresses. This review discusses the effects of different PTMs on RBOH function and their biological relevance. Additionally, we examine the evolutionary conservation of PTM sites and emphasize the complex interplay between multiple PTMs regulating RBOHs.

Dietary Administration Effects of Microbial Exopolysaccharide from Bacillus subtilis P1 on Growth Performance and Immunity in Nile Tilapia (Oreochromis niloticus)

Exopolysaccharide (EPS)-producing bacteria were isolated from the intestines of freshwater fish as prebiotics. Among the isolates, Bacillus sp. P1 was the potent EPS producer, with a high EPS production, and was then identified as Bacillus subtilis P1 based on 16S rRNA and biochemical characteristics. The produced microbial EPS was characterized by its functional groups by FTIR, showing a 90.20% correlation to inulin, while the EPS molecular weight was approximately 105 Da with a high PDI (>1.5). Moreover, the EPS from B. subtilis P1 was assessed for prebiotic properties by growing probiotic bacteria, and significant cell growth occurred in sugar-free TSB with 0.5% EPS (p < 0.05). EPS exhibited approximately 55.37% DPPH radical scavenging at 20 mg/mL and inhibited certain fish pathogens at 400 μg/mL (10–13 mm inhibition zone). Low EPS cytotoxicity was confirmed (<1% hemolysis) prior to use as immunobiotics in Nile Tilapia (Oreochromis niloticus) diet supplementation. Nile tilapia growth and immune response were monitored after feeding with control (C), basal diet (BD), and treatment (T): BD + EPS 5 g/kg. In the T-group, the weight gain (WG), % specific growth rate (SGR), and average daily gain (ADG) significantly increased compared to the control (p < 0.05) by week 4, with no negative effects on blood chemistry parameters. Lysozyme activity and respiratory burst activity in T-groups were significantly higher than the control (p < 0.05), with a 50% RLP survival rate of Nile Tilapia infected by Aeromonas veronii in the T-group after a two-week challenge. On the other hand, the proximate analysis revealed higher protein content in the T-group. These findings suggest that EPS from B. subtilis P1 in fish diets efficiently supports fish growth and stimulates innate immune response in Nile Tilapia, thus showing potential as the immunobiotics for aquaculture.

Semaglutide modulates pro-inflammatory neutrophil phenotype induced by supraphysiological levels of the adipokine FABP4 in patients with cardiovascular disease

Abstract Background Increased adiposity is a risk factor for cardiovascular disease (CVD). Adipose tissue is an endocrine organ that releases proteins with pro-inflammatory effects. One of them is FABP4, which levels are increased after adipogenesis. Insulin resistance is linked to supraphysiological levels of this biomarker. Therapies to reduce body weight and improve insulin response, such as the GLP-1 receptor agonists, like semaglutide, have been shown to benefit patients with CVD and obesity, who have a high pro-inflammatory neutrophil profile. Purpose To study the FABP4 effects on neutrophils from patients with cardiovascular disease and cellular models and its possible modulation by semaglutide. Methods We included 11 patients undergoing open heart surgery. Neutrophils from blood were isolated by single-step centrifugation, counted, and same number were treated with FABP4 (100 ng/mL), semaglutide (1nM) or both. Finally, their phenotype was assessed using flow cytometry (FACS). The same treatment conditions were used on differentiated HL-60 cells (dHL-60) to test their phenotype and functionality based on a) oxidative burst capacity using dihydrorhodamine 123 and b) adhesion to coronary artery endothelial cells. At the end, neutrophils phenotype was tested on patients with obesity and diabetes under semaglutide treatment for 6 months, according to clinical practice. Neutrophils phenotype was determined by FACS and FABP4/C5a plasma levels by immunofluorescence assay. Results FABP4 reduced neutrophils’ CD88 (p=0.006) and CXCR2 (p=0.02) levels. This was also verified in dHL60 cells (p=0.01). In these cells, we were also able to observe a CD11b increment after FABP4 treatment (p=0.04), modulated by semaglutide (p=0.02). This phenotype increased the neutrophil-coronary adhesion (p=0.03). Their oxidative burst capacity was attenuated after semaglutide treatment. In addition, 32% of patients underwent semaglutide treatment reduced plasmatic FABP4 (p=0.03) levels and increased CD88 (p=0.01). We confirmed that CD88 modulation does not lead to a change in plasma C5a. Conclusions High FABP4 levels reduce CD88 of neutrophils from patients with cardiovascular disease and enhance their adhesion to coronary endothelial cells. Modulation of the FABP4 effects by semaglutide treatment might suggest a protective mechanism against adiposity/coronary endothelial inflammation.

Conditional over-expression of heme-oxygenase 1 in myelomonocytic cells reduces AngII-induced hypertension and vascular inflammation in mice

Abstract Background Systemic arterial Hypertension is one of the most important risk factor responsible for morbidity and mortality world-wide. Angiotensin II (Ang II), a potent vasoconstrictor and key player in the renin-angiotensin-aldosterone system (RAAS) is responsible for vascular dysfunction, inflammation, and tissue damage. Heme oxygenase-1 (HO-1) overexpression may confer antioxidant and anti-inflammatory properties in Ang II-induced hypertension through its action on heme catabolism, generating carbon monoxide (CO), ferritin and biliverdin/bilirubin by the action of biliverdin reductase A (BLVRA). Methods and results Male 9–12-weeks-old HO-1indxLySMCre/wt and LySMCre/wt mice were infused with AngII (1mgAngII/Day/Kg) for 7 days to induce hypertension and compared to sham treatment. Blood pressure monitoring by tail-cuff method, and endothelium-dependent vasodilator studies via organ chamber system using acetylcholine (ACh) in isolated aortic segments (~4 mm), revealed that overexpression of HO-1 in myeloid cells resulted in decreased systolic blood pressure and improved endothelial function in AngII-infused HO-1indxLySMCre/wt mice compared to controls. Concurrently, increased BLVRA expression in liver tissue and elevated plasma bilirubin levels were detected by transcriptome analysis and high-performance liquid chromatography, respectively. These results were supported by a reduction in the expression of inducible cytokines and cell adhesion molecules (CAMs) in the aorta, assessed using qPCR. Bone marrow transplant experiments demonstrated that bone marrow from LysMcre mice in HO-1indxLySMCre/wt mice abrogated the protective effect of HO-1, resulting in endothelial damage and increased blood pressure, potentially due to decreased liver BLVRA expression and the accumulation of bone marrow-derived cells in the vessel wall in response to AngII. Additionally, adeno-associated viral vector (AAV) transfection targeting specifically BLVRA activity in liver lead to an increase in blood pressure values and worse endothelium relaxation, in parallel with higher oxidative stress and the blood neutrophils concentration, as assessed in whole blood by using oxidative burst method and blood count system respectively. Conclusion The overexpression of HO-1 in myeloid cells confers anti-inflammatory protection in AngII-induced arterial hypertension in mice. Myeloid cells bone marrow-derived overexpressing HO-1 regulate the differentiation and infiltration of pro-inflammatory immune cells in the vasculature. BLVRA expression and bilirubin levels downstream of HO-1 play a critical role in protecting against vascular damage by reducing leukocyte infiltration.

Functions and mechanisms of CDPKs in plant responses to abiotic stress

Calcium-dependent protein kinases (CDPKs/CPKs) are members of the Ca2+-sensitive Ser/Thr protein kinase family and play a crucial role in plant growth and development and responses to abiotic stress. CDPKs are capable of rapidly sensing changes in intracellular Ca2+ signals and recognizing and phosphorylating specific substrates, thereby transmitting and amplifying Ca2+ signal cascades downstream. They are involved in plant responses to stress conditions such as drought, saline-alkali stress, and injuries and regulate plant growth and development, gene expression, ion channel activity, and stomatal movement. The autophosphorylation of CDPKs can affect their activities and substrate specificity. CDPKs have the ability to bind to and phosphorylate multiple substrates. In addition to participating in respiratory burst oxidase homolog (RBOH), mitogen-activated protein kinase (MAPK), and plant hormone signaling pathways, CDPKs can also bind to 14-3-3 proteins, which enables the regulation of plant responses to stress and promotes plant growth and development. This paper summarized the research findings on the discovery, structure, classification, and roles of CDPKs in plant responses to stress and proposed the future research directions, aiming to provide the genetic resources and a theoretical basis for improving the stress tolerance of crops.

Hematobiochemical Changes, Immunological Response and Immune Gene Expression in Nile Tilapia (Oreochrom niloticus) Experimentally Infected with Shewanella putrefaciens

Background: In this work, hematobiochemical changes, immunological responses, and histopathological changes in Nile tilapia (Oreochromis niloticus) experimentally infected with Shewanella putrefaciens were studied. Methods: O. niloticus was experimentally infected with S. putrefaciens (4SK/SRLFDA/19) at a concentration of 1.508×106CFU/ml per fish. Gross symptoms, namely hemorrhage on the body surface, skin discoloration, slow or nervous behavior, shallow necrotizing ulcers on the skin, fin erosions and abdominal distension were observed 5 to 6 days after infection. Fish were anesthetized and blood samples were collected at 0, 2, 4, 7, 10, 14, 20 and 27 days after the experimental infection to assess the hematobiochemical and immunological responses. For haematobiochemical responses, tests that included hemoglobin (Hb), leukocyte count (Lc), erythrocyte, hematocrite (Ht), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), cholesterol (CHO), glucose (GLU) and triglyceride were assessed. Result: Values of hematocrit, hemoglobin, albumin, globulin, erythrocyte, MCHC, cholesterol and triglyceride were significantly (p less than 0.05) decreased. Lc, MCV, MCH, and glucose values were significantly (p less than 0.05) increased. Respiratory burst activity (RBA) and serum total protein values were significantly (p less than 0.05) decreased. Relative expression of immune gene toll like receptor 4 (TLR4), stress genes heat shock proteins 70, 90 (HSP70, HSP90), oxidative stress gene glutathione S-transferases (GST) and inflammatory gene interleukin 6 (IL6) was significantly higher in experimentally infected fishes compared to control.

Growth performance, immunological, and biochemical responses of stinging catfish, (Heteropneustes fossilis) fingerlings reared in a biofloc-based production system

ABSTRACT A study was conducted to compare the high-density rearing of stinging catfish (Heteropneustes fossilis) fingerlings in both a control system and a biofloc system over 100 days. In the biofloc system, probiotics and a carbon source were added, while the control group had no additions. The biofloc system showed significantly (p < .05) higher floc volume (8.34 ± 1.33 ml L−1) and improvements in growth performance, survival rate, and biomass yield. Fingerlings reared in the biofloc system had increased digestive, oxidative enzyme activities and a lower feed conversion ratio. No changes were observed in the whole-body proximate composition between the groups. However, nonspecific immune responses, such as lysozyme and myeloperoxidase, were relatively improved, and other immune parameters like respiratory burst activity and total serum immunoglobulin were significantly increased in the biofloc system. In conclusion, biofloc-based rearing significantly enhanced the growth performance, feed utilization, and immunological conditions of stinging catfish.

Positive effects of yeast soluble cell wall polysaccharide on fruit postharvest control through resistance response

Yeast-derived cell wall polysaccharides possess numerous biological activities, but their application in postharvest preservation is rarely reported. The aim of this research was to investigate the effects of Kluyveromyces marxianus soluble cell wall polysaccharide (SCWP) on preventing the infection of Penicillium expansum in pear fruit. The results showed that K. marxianus SCWP treatment could significantly improve the resistance of pear fruit to P. expansum, with respect to Saccharomyces cerevisiae-derived SCWP. Composition of both SCWPs was mannan with the main chains consisting of a → 6)-α-D-Manp-(1 → unit and the branch structure formed by → 2)-α-D-Manp-(1 except that K. marxianus SCWP took on a shorter side chain and a rougher surface than S. cerevisiae SCWP. In addition, mechanisms of K. marxianus SCWP on stimulating resistance response were associated with the apparent oxidative burst, increased gene expression and enzyme activity of antioxidant and defense systems in pear fruit. Our findings suggest that K. marxianus SCWP can be used as an innovative and promising candidate for preventing postharvest fungal decay and extending fruit shelf life.

The leucine-rich repeat receptor kinase QSK1 regulates PRR-RBOHD complexes targeted by the bacterial effector HopF2Pto.

Plants detect pathogens using cell-surface pattern recognition receptors (PRRs) such as ELONGATION Factor-TU (EF-TU) RECEPTOR (EFR) and FLAGELLIN SENSING 2 (FLS2), which recognize bacterial EF-Tu and flagellin, respectively. These PRRs belong to the leucine-rich repeat receptor kinase (LRR-RK) family and activate the production of reactive oxygen species via the NADPH oxidase RESPIRATORY BURST OXIDASE HOMOLOG D (RBOHD). The PRR-RBOHD complex is tightly regulated to prevent unwarranted or exaggerated immune responses. However, certain pathogen effectors can subvert these regulatory mechanisms, thereby suppressing plant immunity. To elucidate the intricate dynamics of the PRR-RBOHD complex, we conducted a comparative coimmunoprecipitation analysis using EFR, FLS2, and RBOHD in Arabidopsis thaliana. We identified QIAN SHOU KINASE 1 (QSK1), an LRR-RK, as a PRR-RBOHD complex-associated protein. QSK1 downregulated FLS2 and EFR abundance, functioning as a negative regulator of PRR-triggered immunity (PTI). QSK1 was targeted by the bacterial effector HopF2Pto, a mono-ADP ribosyltransferase, reducing FLS2 and EFR levels through both transcriptional and transcription-independent pathways, thereby inhibiting PTI. Furthermore, HopF2Pto transcriptionally downregulated PROSCOOP genes encoding important stress-regulated phytocytokines and their receptor MALE DISCOVERER 1-INTERACTING RECEPTOR-LIKE KINASE 2. Importantly, HopF2Pto requires QSK1 for its accumulation and virulence functions within plants. In summary, our results provide insights into the mechanism by which HopF2Pto employs QSK1 to desensitize plants to pathogen attack.

Immune protective, stress indicators, antioxidant, histopathological status, and heat shock protein gene expression impacts of dietary Bacillus spp. against heat shock in Nile tilapia, Oreochromis niloticus

This research evaluated the efficacy of mixed Bacillus strains probiotic supplements in mitigating acute thermal-induced stress in Nile tilapia (Oreochromis niloticus). Three experimental fish groups involved 135 Nile tilapia (49 ± 2 g); one control (no added probiotics), 0.5, and 1% of selected Bacillus strains (B. subtilis, B. licheniformis, and B. pumilus) for 58 days. After the feeding period, growth parameters, immunological parameters, stress biochemical markers, and antioxidant parameters in addition to genes related to stress and histopathological changes in fish, were assessed; subsequently subjected to heat shock at 36 ± 0.5 ◦C for 2 h. Before the heat challenge, our results exhibited a marked increase in the growth efficacy (P < 0.05), lower marked serum levels of triglycerides and cholesterol, and tissue malondialdehyde (MDA) levels along with significantly increased superoxide dismutase (SOD) and catalase (CAT) enzymes activity in fish-fed Bacillus probiotic at 0.5% concerning the control group (P < 0.05). There were no significant changes in the serum levels of glucose, cortisol, lactate, phagocytic activity, respiratory burst (ROS), total immunoglobulin Ig, alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), total protein, albumin, globulin, uric acid, urea, creatinine, as well as HSP70, GST, and GPx mRNA expression in most of the probiotic groups compared to the control group (P > 0.05). When Nile tilapia was exposed to heat stress, supplementation with Bacillus probiotic in the diet significantly decreased most of the indices related to serum biochemical (ALT (P < 0.01; P < 0.001), AST (P < 0.01), LDH (P < 0.01), urea (P < 0.05), and creatinine (P < 0.01)), triglycerides (P < 0.001; (P < 0.01)), cholesterol (P < 0.01; (P < 0.05)), glucose (P < 0.001), and cortisol (P < 0.01; (P < 0.05)), with tissue oxidative stress MDA levels (P < 0.05), and HSP70 mRNA expression (P < 0.01; P < 0.001), aligned with the stressed control group. In addition, a notable upsurge in the total protein, albumin, globulin, phagocytic and ROS activities, and total Ig, as well as the enzymatic antioxidant ability (SOD, CAT) (P < 0.01), with GST and GPx mRNA expression (P < 0.05; P < 0.01), were shown in fish-fed Bacillus spp. post-exposure compared with the stressed control group. Besides, no histopathological alterations were revealed in the spleen and brain of fish pre- and post-heat exposure. According to our findings, diet supplementation of Bacillus species has the potential to combat the suppressive effects of heat shock in Nile tilapia.

Comparative Effects of Crude Extracts and Bioactive Compounds from Bidens pilosa and Bidens alba on Nonspecific Immune Responses and Antibacterial Activity Against Vibrio sp. in Coculture with Lactic Acid Bacteria in Hybrid Grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂).

This study investigated the effect of substances on nonspecific immune responses of head kidney leukocytes, the antimicrobial activity against Vibrio sp., as well as the time-kill of Vibrio sp. by combining the substances with lactic acid bacteria (LAB) and Pediococcus sp. The substances are B. pilosa hot water extract, B. pilosa powder extract, B. pilosa methanol extract, B. pilosa ethanol extract, B. alba hot water extract, B. alba powder extract, B. alba methanol extract, B. alba ethanol extract, and bioactive compounds, namely cytopiloyne, flavonoid, phenol, ethyl caffeate, luteolin, chlorogenic acid, butein, and linoleic acid. The results showed that some of them were nontoxic to the head kidney leukocytes, which can increase the phagocytic rate, phagocytic index, and respiratory burst. These substances were able to inhibit the growth of Vibrio sp.; they can even completely kill the pathogenic bacteria. The largest of the inhibition zone formed from the EC group at a concentration range of 5-50 µg/mL against V. parahaemolyticus, V. alginolyticus, and V. harveyi with a value of 19.7 ± 0.56, 19.3 ± 1.53, and 20.6 ± 1.53 mm. Furthermore, the time-kill studies showed that the LAB and P. acidilactici can completely kill the Vibrio sp. at 6 h incubation time, mainly in the group of combination with EC.

Impact of Nitric Oxide on Polymorphonuclear Neutrophils' Function.

There is increasing evidence that nitric oxide (nitrogen monoxide, NO) significantly influences immune cellular responses, including those from polymorphonuclear leukocytes (PMNs). The aim of this study was to examine a possible effect of NO on PMNs' function (chemotaxis, production of reactive oxygen species (ROS), and NETosis) using live cell imaging. Moreover, we investigated PMN surface epitope and neutrophil oxidative burst under the influence of NO by flow cytometric analysis. Whole blood samples were obtained from healthy volunteers, and PMNs were isolated by density centrifugation. Live cell imaging using type I collagen matrix in µSlide IBIDI chemotaxis chambers was conducted in order to observe N-formyl-L-methionyl-L-leucyl-phenylalanine (fMLP)-stimulated PMN chemotaxis, ROS production, and NETosis. In the test group, NO was continuously redirected into the climate chamber of the microscope, so the chemotaxis chambers were surrounded by NO. The same experimental setup without NO served as a control. In addition, isolated PMNs were incubated with nitrogen monoxide (NO) or without (the control). Subsequently, flow cytometry was used to analyze neutrophil antigen expression and oxidative burst. Our live cell imaging results demonstrated a migration-promoting effect of NO on PMNs. We observed that in the case of prior stimulation by fMLP, NO has no effect on the time course of neutrophil ROS production and NET release. However, flow cytometric analyses demonstrated an increase in ROS production after pretreatment with NO. No NO-dependent differences for the expression of CD11b, CD62L, or CD66b could be observed. We were able to demonstrate a distinct effect of NO on PMNs' function. The complex interaction between NO and PMNs remains a major research focus, as the exact mechanisms and additional influencing factors remain elusive. Future studies should explore how varying NO concentrations and the timing of NO exposure relative to PMN activation affect its influence.