Inter-species interactions between two bacterial flower commensals and a floral pathogen reduce disease incidence and alter pathogen activity.

Flowers are colonized by a diverse community of microorganisms that can alter plant health and interact with floral pathogens. Erwinia amylovora is a flower-inhabiting bacterium and a pathogen that infects different plant species, including Malus × domestica (apple). Previously, we showed that the co-inoculation of two bacterial strains, members of the genera Pseudomonas and Pantoea, isolated from apple flowers, reduced disease incidence caused by this floral pathogen. Here, we decipher the ecological interactions between the two flower-associated bacteria and E. amylovora in field experimentation and in vitro co-cultures. The two flower commensal strains did not competitively exclude E. amylovora from the stigma habitat, as both bacteria and the pathogen co-existed on the stigma of apple flowers and in vitro. This suggests that plant protection might be mediated by other mechanisms than competitive niche exclusion. Using a synthetic stigma exudation medium, ternary co-culture of the bacterial strains led to a substantial alteration of gene expression in both the pathogen and the two microbiota members. Importantly, the gene expression profiles for the ternary co-culture were not just additive from binary co-cultures, suggesting that some functions only emerged in multipartite co-culture. Additionally, the ternary co-culture of the strains resulted in a stronger acidification of the growth milieu than mono- or binary co-cultures, pointing to another emergent property of co-inoculation. Our study emphasizes the critical role of emergent properties mediated by inter-species interactions within the plant holobiont and their potential impact on plant health and pathogen behavior. IMPORTANCE: Fire blight, caused by Erwinia amylovora, is one of the most important plant diseases of pome fruits. Previous work largely suggested plant microbiota commensals suppressed disease by antagonizing pathogen growth. However, inter-species interactions of multiple flower commensals and their influence on pathogen activity and behavior have not been well studied. Here, we show that co-inoculating two bacterial strains that naturally colonize the apple flowers reduces disease incidence. We further demonstrate that the interactions between these two microbiota commensals and the floral pathogen led to the emergence of new gene expression patterns and a strong alteration of the external pH, factors that may modify the pathogen's behavior. Our findings emphasize the critical role of emergent properties mediated by inter-species interactions between plant microbiota and plant pathogens and their impact on plant health.

Nanoscale sulfur alters the bacterial and eukaryotic communities of the tomato rhizosphere and their interactions with a fungal pathogen.

Nanoformulations of sulfur have demonstrated the potential to enhance plant growth and reduce disease incidence when plants are confronted with pathogens. However, the impact of nanoscale sulfur on microbial communities in close contact with the plant root, known as the rhizosphere, remain poorly characterized. In this study, we investigate the impact of three formulations of sulfur; bulk sulfur, uncoated (pristine) sulfur nanoparticles, and stearic acid coated sulfur nanoparticles, on the rhizosphere of tomato plants. Tomato plants were additionally challenged by the pathogenic fungus Fusarium oxysporum f. sp. Lycopersici. Employing bacterial 16S rRNA gene sequencing, along with recently in-house designed peptide nucleic acid clamps to facilitate the recovery of microeukaryote sequences, we performed a comprehensive survey of rhizosphere microbial populations. We found the largest influence on the composition of the rhizosphere microbiome was the presence of the fungal pathogen. However, sulfur amendments also drove state changes in the rhizosphere populations; for example, enriching the relative abundance of the plant-beneficial sulfur-oxidizing bacterium Thiobacillus. Notably, when investigating the response of the rhizosphere community to the different sulfur amendments, there was a strong interaction between the fungal pathogen and sulfur treatments. This resulted in different bacterial and eukaryotic taxa being enriched in association with the different forms of sulfur, which was dependent on the presence of the pathogen. These data point to nano formulations of sulfur exerting unique shifts in the rhizosphere community compared to bulk sulfur, particularly in association with a plant pathogen, and have implications for the sustainable use of nanoscale strategies in sustainable agriculture.

Cofunctioning of bacterial exometabolites drives root microbiota establishment.

Soil-dwelling microbes are the principal inoculum for the root microbiota, but our understanding of microbe-microbe interactions in microbiota establishment remains fragmentary. We tested 39,204 binary interbacterial interactions for inhibitory activities in vitro, allowing us to identify taxonomic signatures in bacterial inhibition profiles. Using genetic and metabolomic approaches, we identified the antimicrobial 2,4-diacetylphloroglucinol (DAPG) and the iron chelator pyoverdine as exometabolites whose combined functions explain most of the inhibitory activity of the strongly antagonistic Pseudomonas brassicacearum R401. Microbiota reconstitution with a core of Arabidopsis thaliana root commensals in the presence of wild-type or mutant strains revealed a root niche-specific cofunction of these exometabolites as root competence determinants and drivers of predictable changes in the root-associated community. In natural environments, both the corresponding biosynthetic operons are enriched in roots, a pattern likely linked to their role as iron sinks, indicating that these cofunctioning exometabolites are adaptive traits contributing to pseudomonad pervasiveness throughout the root microbiota.

Aureobasidium pullulans from the Fire Blight Biocontrol Product, Blossom Protect, Induces Host Resistance in Apple Flowers.

Fire blight, caused by Erwinia amylovora, is a devastating disease of apple. Blossom Protect, a product that contains Aureobasidium pullulans as the active ingredient, is one of the most effective biological controls of fire blight. It has been postulated that the mode of action of A. pullulans is to compete against and antagonize epiphytic growth of E. amylovora on flowers, but recent studies have found that flowers treated with Blossom Protect harbored similar to or only slightly reduced E. amylovora populations compared with nontreated flowers. In this study, we tested the hypothesis that A. pullulans-mediated biocontrol of fire blight is the result of induced host resistance. We found that PR genes in the systemic acquired resistance pathway, but not genes in the induced systemic resistance pathway, were induced in hypanthial tissue of apple flowers after the Blossom Protect treatment. Additionally, the induction of PR gene expression was coupled with an increase of plant-derived salicylic acid in this tissue. After inoculation with E. amylovora, PR gene expression was suppressed in nontreated flowers, but in flowers pretreated with Blossom Protect, the heightened PR expression offset the immune repression caused by E. amylovora, and prevented infection. Temporal and spatial analysis of PR gene induction showed that induction of PR genes occurred 2 days after the Blossom Protect treatment, and required direct flower-yeast contact. Finally, we observed deterioration of the epidermal layer of the hypanthium in some of the Blossom Protect-treated flowers, suggesting that PR gene induction in flowers may be a result of pathogenesis by A. pullulans.

Differential Regulation and Production of Secondary Metabolites among Isolates of the Fungal Wheat Pathogen Zymoseptoria tritici.

The genome of the wheat-pathogenic fungus Zymoseptoria tritici represents extensive presence-absence variation in gene content. Here, we addressed variation in biosynthetic gene cluster (BGC) content and biochemical profiles among three isolates. We analyzed secondary metabolite properties based on genome, transcriptome, and metabolome data. The isolates represent highly distinct genome architecture but harbor similar repertoires of BGCs. Expression profiles for most BGCs show comparable patterns of regulation among the isolates, suggesting a conserved biochemical infection program. For all three isolates, we observed a strong upregulation of a putative abscisic acid (ABA) gene cluster during biotrophic host colonization, indicating that Z. tritici interferes with host defenses by the biosynthesis of this phytohormone. Further, during in vitro growth, the isolates show similar metabolomes congruent with the predicted BGC content. We assessed if secondary metabolite production is regulated by histone methylation using a mutant impaired in formation of facultative heterochromatin (H3K27me3). In contrast to other ascomycete fungi, chromatin modifications play a less prominent role in regulation of secondary metabolites. In summary, we show that Z. tritici has a conserved program of secondary metabolite production, contrasting with the immense variation in effector expression, and some of these metabolites might play a key role during host colonization. IMPORTANCE Zymoseptoria tritici is one of the most devastating pathogens of wheat. So far the molecular determinants of virulence and their regulation are poorly understood. Previous studies have focused on proteinaceous virulence factors and their extensive diversity. In this study, we focus on secondary metabolites produced by Z. tritici. Using a comparative framework, we characterize core and noncore metabolites produced by Z. tritici by combining genome, transcriptome, and metabolome data sets. Our findings indicate highly conserved biochemical profiles with contrasting genetic and phenotypic diversity of the field isolates investigated here. This discovery has relevance for future crop protection strategies.

Facile preparation of covalently functionalized graphene with 2,4-dinitrophenylhydrazine and investigation of its characteristics.

This article reports a fast and easy method for simultaneously in situ reducing and functionalizing graphene oxide. 2,4-Dinitrophenylhydrazine hydrate salt molecules are reduced by graphene oxide by reacting with oxide groups on the surface and removing these groups, and 2,4-dinitrophenylhydrazone groups are replaced with oxide groups. The synthesized materials have been investigated using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and UV absorption. Also, the morphology has been examined with a scanning electron microscope (SEM) and Brunauer-Emmett-Teller (BET) analysis. The result of the photocurrent response and electrochemical behavior of the samples through cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy (EIS) have been analyzed to investigate the effect of physical and chemical changes compared to graphene.

Comparison of Single Photon Emission Computed Tomography (SPECT) and implantable Doppler in the monitoring of a vascularised fibular free flap for reconstruction of the mandible.

Monitoring of microvascular free flaps is an influencing factor in the success or failure of the treatment. In this study, we aim to compare the accuracy of implantable Doppler and scintigraphy in the monitoring of a vascularised buried fibular graft for reconstruction of the mandible. In a prospective cohort study, an implantable Doppler was placed intraoperatively, and Single Photon Emission Computed Tomography (SPECT) was taken in patients when abnormal blood flow was detected via the implantable Doppler or 48 hours after operations in patients with normal signals on the Doppler. The flaps were explored if patients did not have regular signals via implantable Doppler or if SPECT revealed impaired perfusion. The number of true- and false-positive cases and true- and false-negative cases were documented. Positive predictive value (PPV) and negative predictive value (NPV) were calculated. Eighteen (29%) of 62 patients underwent explorative surgery. The sensitivity of SPECT was 38.88%, and specificity was 97.72%. In SPECT, PPV was 87.50% and NPV 79.62%. The sensitivity of the implantable Doppler was 72.22%, and specificity was 93.08%. In assessment with the implantable Doppler, PPV was 81.25% and NPV 93.18%. It seems that SPECT and the implantable Doppler had sufficient specificity in the monitoring of a buried fibular graft. However, SPECT had a lower sensitivity than the implantable Doppler.

Role of Vitamin D as Protective Agent against Induced Liver Damage in Male Rats.

One of the main factors which played a key role in the prevention of liver disorders such as hepatic inflammation, fibrosis, and carcinogenesis would be the vitamin D axis. Therefore, the current research was designed to evaluate the role of Vitamin D (Vit D)   as a protective agent against liver damage caused by Thioacetamide (TAA). In the current study, 18 male Wistar rats were randomly allocated into three equal groups (n=6): in group 1(G1) the animals were considered as the control group and did not receive any supplement in drinking water; in group 2 (G2) TAA was administrated to the drinking water at a dose of 300 mg/L; in group 3 (G3) TAA was administrated to the drinking water at a dose of 300 mg/L plus vitamin D at a dose of 0.5 mg/100g body (intraperitoneal) for 8 weeks. At the end of the experiment, the animals were sacrificed and the liver was dissected and removed for histopathology. Histopathological evaluations were used to evaluate the possible adverse effects of TAA on the liver. Several hepatic damages were observed in the G2 group such as lobular disorder, some degrees of degeneration in hepatocytes and enlargement of the hepatic capillaries, and focal necrotic areas. Hepatic fibrosis was observed around portal areas and central veins. Bridging fibrous septa were formed between portal veins. The recorded data in this study showed that Vit D has some beneficial effects in protecting the liver from fibrosis and toxic damages. The recorded data showed that liver damages in the G3 group were partially prevented or cured. In conclusion, it is evident that the Vit D played a pivotal role as an antioxidant and anti-fibrotic agent, therefore it would be the best supplement for liver protection against damages due to toxin entrance into the animal's body.

Seed-Derived Microbial Colonization of Wild Emmer and Domesticated Bread Wheat (Triticum dicoccoides and T. aestivum) Seedlings Shows Pronounced Differences in Overall Diversity and Composition.

The composition of the plant microbiota may be altered by ecological and evolutionary changes in the host population. Seed-associated microbiota, expected to be largely vertically transferred, have the potential to coadapt with their host over generations. Strong directional selection and changes in the genetic composition of plants during domestication and cultivation may have impacted the assembly and transmission of seed-associated microbiota. Nonetheless, the effect of plant speciation and domestication on the composition of these microbes is poorly understood. Here, we have investigated the composition of bacteria and fungi associated with the wild emmer wheat (Triticum dicoccoides) and domesticated bread wheat (Triticum aestivum). We show that vertically transmitted bacteria, but not fungi, of domesticated bread wheat species T. aestivum are less diverse and more inconsistent among individual plants compared to those of the wild emmer wheat species T. dicoccoides. We propagated wheat seeds under sterile conditions to characterize the colonization of seedlings by seed-associated microbes. Hereby, we show markedly different community compositions and diversities of leaf and root colonizers of the domesticated bread wheat compared to the wild emmer wheat. By propagating the wild emmer wheat and domesticated bread wheat in two different soils, we furthermore reveal a small effect of plant genotype on microbiota assembly. Our results suggest that domestication and prolonged breeding have impacted the vertically transferred bacteria, but only to a lesser extent have affected the soil-derived microbiota of bread wheat.IMPORTANCE Genetic and physiological changes associated with plant domestication have been studied for many crop species. Still little is known about the impact of domestication on the plant-associated microbiota. In this study, we analyze the seed-associated and soil-derived bacterial and fungal microbiota of domesticated bread wheat and wild emmer wheat. We show a significant difference in the seed-associated, but not soil-derived, bacterial communities of the wheat species. Interestingly, we find less pronounced effects on the fungal communities. Overall, this study provides novel insight into the diversity of vertically transmitted microbiota of wheat and thereby contributes to our understanding of wheat as a "metaorganism." Insight into the wheat microbiota is of fundamental importance for the development of improved crops.

Ascher's syndrome: a rare cause of lip swelling.

Ascher's syndrome is a rare, benign entity with just over 100 reported cases. The condition is characterised by a 'double' upper lip, blepharochalasis and non-toxic thyroid enlargement. It presents before the age of 20 years in the majority of cases and shows no racial or gender differences. While the exact cause is unknown, hormonal dysfunction and autosomal dominant inheritance have been suggested as possible aetiological factors. We present two cases of Ascher's syndrome referred for investigation of lip swelling.

A fungal pathogen induces systemic susceptibility and systemic shifts in wheat metabolome and microbiome composition.

Yield losses caused by fungal pathogens represent a major threat to global food production. One of the most devastating fungal wheat pathogens is Zymoseptoria tritici. Despite the importance of this fungus, the underlying mechanisms of plant-pathogen interactions are poorly understood. Here we present a conceptual framework based on coinfection assays, comparative metabolomics, and microbiome profiling to study the interaction of Z. tritici in susceptible and resistant wheat. We demonstrate that Z. tritici suppresses the production of immune-related metabolites in a susceptible cultivar. Remarkably, this fungus-induced immune suppression spreads within the leaf and even to other leaves, a phenomenon that we term "systemic induced susceptibility". Using a comparative metabolomics approach, we identify defense-related biosynthetic pathways that are suppressed and induced in susceptible and resistant cultivars, respectively. We show that these fungus-induced changes correlate with changes in the wheat leaf microbiome. Our findings suggest that immune suppression by this hemibiotrophic pathogen impacts specialized plant metabolism, alters its associated microbial communities, and renders wheat vulnerable to further infections.

Interactions and Coadaptation in Plant Metaorganisms.

Plants associate with a wide diversity of microorganisms. Some microorganisms engage in intimate associations with the plant host, collectively forming a metaorganism. Such close coexistence with plants requires specific adaptations that allow microorganisms to overcome plant defenses and inhabit plant tissues during growth and reproduction. New data suggest that the plant immune system has a broader role beyond pathogen recognition and also plays an important role in the community assembly of the associated microorganism. We propose that core microorganisms undergo coadaptation with their plant host, notably in response to the plant immune system allowing them to persist and propagate in their host. Microorganisms, which are vertically transmitted from generation to generation via plant seeds, putatively compose highly adapted species and may have plant-beneficial functions. The extent to which plant domestication has impacted the underlying genetics of plant-microbe associations remains poorly understood. We propose that the ability of domesticated plants to select and maintain advantageous microbial partners may have been affected. In this review, we discuss factors that impact plant metaorganism assembly and function. We underline the importance of microbe-microbe interactions in plant tissues, as they are still poorly studied but may have a great impact on plant health.

miPIE: NGS-based Prediction of miRNA Using Integrated Evidence.

Methods for the de novo identification of microRNA (miRNA) have been developed using a range of sequence-based features. With the increasing availability of next generation sequencing (NGS) transcriptome data, there is a need for miRNA identification that integrates both NGS transcript expression-based patterns as well as advanced genomic sequence-based methods. While miRDeep2 does examine the predicted secondary structure of putative miRNA sequences, it does not leverage many of the sequence-based features used in state-of-the-art de novo methods. Meanwhile, other NGS-based methods, such as miRanalyzer, place an emphasis on sequence-based features without leveraging advanced expression-based features reflecting miRNA biosynthesis. This represents an opportunity to combine the strengths of NGS-based analysis with recent advances in de novo sequence-based miRNA prediction. We here develop a method, microRNA Prediction using Integrated Evidence (miPIE), which integrates both expression-based and sequence-based features to achieve significantly improved miRNA prediction performance. Feature selection identifies the 20 most discriminative features, 3 of which reflect strictly expression-based information. Evaluation using precision-recall curves, for six NGS data sets representing six diverse species, demonstrates substantial improvements in prediction performance compared to three methods: miRDeep2, miRanalyzer, and mirnovo. The individual contributions of expression-based and sequence-based features are also examined and we demonstrate that their combination is more effective than either alone.

Immunological and hematological effects of IL-5(Rα)-targeted therapy: An overview.

IL-5 is an important cytokine for priming and survival of mature eosinophils and for proliferation and maturation of their progenitors. Hence, IL-5(Rα) targeting will be increasingly used in diseases where eosinophils are the key immune effector cells such as eosinophilic asthma (EA), hypereosinophilic syndrome (HES), eosinophilic esophagitis (EE), and eosinophilic granulomatosis with polyangiitis (EGPA). Therefore, several neutralizing monoclonal antibodies directed against IL-5 (mepolizumab and reslizumab) and its receptor IL-5Rα (benralizumab) have found or will find their way to the clinic. While the clinical effect of these drugs has been extensively investigated and reviewed, the understanding of the underlying immunological and hematological mechanisms remains less clear. This review will discuss the translational outcomes of treatment with these monoclonal antibodies in humans to shed light on the mechanisms underlying the main immunological and hematological findings from these clinical trials in humans.

Microbial interactions within the plant holobiont.

Since the colonization of land by ancestral plant lineages 450 million years ago, plants and their associated microbes have been interacting with each other, forming an assemblage of species that is often referred to as a "holobiont." Selective pressure acting on holobiont components has likely shaped plant-associated microbial communities and selected for host-adapted microorganisms that impact plant fitness. However, the high microbial densities detected on plant tissues, together with the fast generation time of microbes and their more ancient origin compared to their host, suggest that microbe-microbe interactions are also important selective forces sculpting complex microbial assemblages in the phyllosphere, rhizosphere, and plant endosphere compartments. Reductionist approaches conducted under laboratory conditions have been critical to decipher the strategies used by specific microbes to cooperate and compete within or outside plant tissues. Nonetheless, our understanding of these microbial interactions in shaping more complex plant-associated microbial communities, along with their relevance for host health in a more natural context, remains sparse. Using examples obtained from reductionist and community-level approaches, we discuss the fundamental role of microbe-microbe interactions (prokaryotes and micro-eukaryotes) for microbial community structure and plant health. We provide a conceptual framework illustrating that interactions among microbiota members are critical for the establishment and the maintenance of host-microbial homeostasis.

Value of Histopathologic Findings of Post-reperfusion Liver Needle Biopsies.

BACKGROUND: Histopathologic changes of post-reperfusion liver needle biopsies in patients with liver transplantation have rarely been reported and most of the previous reports have been in less than 200 cases. OBJECTIVE: In this study, we evaluated 408 post-perfusion liver needle biopsies for the histopathologic changes attributable to reperfusion injury and compared them with early post-liver transplantation outcome, to find out the value of these findings. METHODS: In 408 patients who underwent liver transplantation, post-perfusion liver needle biopsy was taken within one hour of vascular anastomosis. The specimens were fixed in formalin and evaluated by a hepatopathologist blinded to the outcome of transplantation for hepatocellular necrosis, apoptosis, ballooning degeneration, cholestasis, neutrophilic infiltration, and steatosis. These were compared with cold and warm ischemic time, levels of AST, ALT, alkaline phosphatase, bilirubin, presence or absence of rejection, and duration of hospital stay. RESULTS: Hepatocellular ballooning degeneration, apoptosis, and necrosis did not show any significant correlations with early post-transplantation outcome and reperfusion injury. However, presence of neutrophilic infiltration in the post-reperfusion liver biopsy was well correlated with liver function tests and other clinical and paraclinical findings. Presence of steatosis in post-reperfusion liver needle biopsy was also associated with high liver function tests and long hospital stay. CONCLUSION: Presence of PMN leukocytes in the post-perfusion liver needle biopsy of transplanted liver is associated with poor early outcome and reperfusion injury, so it should be recorded in the pathology report and should be considered a high-risk sign for the clinicians.

Tumoral calcinosis: Diffuse multifocal form in hemodialysis patients. Two case reports.

Orthopedic surgeons are often consulted for diagnosis of MASS syndrome, imaging showing periarticular calcification, or joint stiffness. Such presentations in a dialyzed patient should suggest tumoral calcinosis, which is a rare complication of dialysis, often diagnosed wrongly or late. It is often associated with calcium phosphate balance disorder, in which treatment is difficult and must take account of known contributing factors: severe hyperparathyroidism, increased phosphocalcic product, therapeutic calcium and vitamin D overload, and bone turnover slowed for varying reasons. We report a clinical, radiological and therapeutic description of two cases of tumoral calcinosis, which consists in deposits of hydroxyapatite, the crystalline form of calcium phosphate, in diffuse multifocal periarticular locations, inducing both esthetic and functional damage.