Isolation and identification of bacterial strains from apple flowers in Trentino and their evaluation as biocontrol agents of Erwinia amylovora

Fire blight caused by Erwinia amylovora (Ea) represents a great threat to apple and pear production worldwide. For instance, the outbreak of fire blight occurred in Trentino caused a relevant reduction of crop yield in 2020. Since Ea can spread rapidly in the environment, it is difficult to manage this devastating phytopathogenic bacterium. It is now widely accepted that apple flowers may harbor bacterial taxa that might hinder the ability of Ea to colonize apple flower. Based on this body of knowledge, we aimed at investigating the microbiota of apple flowers to select new potential biocontrol agents active against Ea. Flowers of Malus domestica cv. Golden Delicious from Trentino apple orchards were sampled at the ‘Baloon stage’ and surface sterilised to isolate only bacteria residing within the flowers. Bacterial isolates were initially selected on R2A dishes according to their colony morphology and subsequently identified through 16S rRNA gene sequencing. The phylogenetic analysis showed the bacterial isolates mainly belonged to the Enterobacteriaceae, Pseudomonadaceae, and Microbacteriaceae families. One member of each bacterial family was selected and tested against Ea both on newly open apple flowers and on pear slices. Preliminary results showed some of these strains might have a significant effect on the control of Ea. In particular, Pantoea agglomerans and Curtobacterium flaccumfaciens strains showed the highest efficacy. In the future, we will carry out further experiments to investigate and understand the modes of action of these bacterial strains

The perception of indole negatively modulates biocontrol activities in the plant beneficial Rhizobacterium Lysobacter capsici AZ78

The rhizosphere is a dynamic environment characterised by multiple and complex microbial interactions where diffusible communication signals (DCS) continuously influence the expression patterns of the microbiome, hence regulating fundamental traits for adaptation to the rhizosphere. In particular, plant-associated bacteria release indole, a Volatile Organic Compound (VOC) that acts as an interkingdom signal able to influence antibiotic resistance, motility, biofilm formation and virulence. Lysobacter spp. are commonly found in the rhizosphere and have been frequently associated to disease suppression. For instance, the biocontrol activity of the plant beneficial bacterium Lysobacter capsici AZ78 (AZ78) has been reported against the phytopathogenic oomycetes Phytophthora infestans, Plasmopara viticola, Pythium ultimum and the Gram-positive bacterium Rhodococcus fascians. However, there is scarce information about Lysobacter spp. ecology and how DCS, and in particular indole, may affect their behaviour in the rhizosphere. To investigate the aspects determining rhizosphere competence and functioning of Lysobacter spp., this work presents a functional and transcriptomic analysis performed on AZ78, which was grown in the presence indole. The presence of indole significantly reduced the inhibition capacity of AZ78 against P. ultimum and R. fascians by 47 and 31%, respectively. Moreover, RNA-Seq analysis revealed that nearly 12% of all genes in AZ78 genome were modulated by indole. In particular, indole downregulated the expression of the heat-stable antifungal factor (HSAF) biosynthetic gene cluster, which may affect AZ78 antioomycete and antimicrobial activity. Moreover, in the presence of indole, AZ78 downregulated several signal transduction pathways responsible for nutrients uptake, resulting in reduced growth. Finally, indole downregulated several genes related to type IV pilus functionality, which might lead to impaired twitching motility. This study sheds light on the key role of DCS such as indole in shaping AZ78 behaviour in the rhizosphere and suggests that, manipulating DCS levels may alter the persistence and functioning of several plant-beneficial rhizobacteria, such as Lysobacter strains

Humic acid enhances the growth of tomato promoted by endophytic bacterial strains through the activation of hormone-, growth-, and transcription-related processes

Plant growth-promoting bacteria (PGPB) are promising alternatives in the reduction of the use of chemical fertilizers. Likewise, humic acid (HA) can improve plant growth and/or the establishment of endophytic PGPB. Although the effects of PGPB colonization or HA treatment have been studied separately, little information is available on plant response to the combined applications of PGPB and HA. Thus, the aim of this work was to understand the physiological effects, bacterial colonization and transcriptional responses activated by endophytic bacterial strains in tomato roots and shoots in the absence (control condition) and presence of HA (HA condition). Tomato shoot length was promoted by seed inoculation with Paraburkholderia phytofirmans PsJN, Pantoea agglomerans D7G, or Enterobacter sp. 32A in the presence of HA, indicating a possible complementation of PGPB and HA effects. Tomato colonization by endophytic bacterial strains was comparable in the control and HA condition. The main transcriptional regulations occurred in tomato roots and the majority of differentially expressed genes (DEGs) was upregulated by endophytic bacterial strains in the HA condition. Half of the DEGs was modulated by two or three strains as possible common reactions to endophytic bacterial strains, involving protein metabolism, transcription, transport, signal transduction, and defense. Moreover, strain-specific tomato responses included the upregulation of signal transduction, transcription, hormone metabolism, protein metabolism, secondary metabolism, and defense processes, highlighting specific traits of the endophyte-tomato interaction. The presence of HA enhanced the upregulation of genes related to signal transduction, hormone metabolism, transcription, protein metabolism, transport, defense, and growth-related processes in terms of number of involved genes and fold change values. This study provides detailed information on HA-dependent enhancement of growth-related processes stimulated by endophytic bacterial strains in tomato plants and reports the optimized dosages, complementation properties and gene markers for the further development of efficient PGPB- and HA-based biostimulant

Prolonged duration of early antibiotic therapy in extremely premature infants.

BackgroundProlonged early antibiotics in extremely premature infants may have negative effects. We aimed to assess prevalence and outcomes of provision of prolonged early antibiotics to extremely premature infants in the absence of culture-confirmed infection or NEC.MethodsCohort study of infants from 13 centers born without a major birth defect from 2008-2014 who were 401-1000 grams birth weight, 22-28 weeks gestation, and survived ≥5 days without culture-confirmed infection, NEC, or spontaneous intestinal perforation. We determined the proportion of infants who received prolonged early antibiotics, defined as ≥5 days of antibiotic therapy started at ≤72 h of age, by center and over time. Associations between prolonged early antibiotics and adverse outcomes were assessed using multivariable logistic regression.ResultsA total of 5730 infants were included. The proportion of infants receiving prolonged early antibiotics varied from 30-69% among centers and declined from 49% in 2008 to 35% in 2014. Prolonged early antibiotics was not significantly associated with death (adjusted odds ratio 1.17 [95% CI: 0.99-1.40], p = 0.07) and was not associated with NEC.ConclusionsThe proportion of extremely premature infants receiving prolonged early antibiotics decreased, but significant center variation persists. Prolonged early antibiotics were not significantly associated with increased odds of death or NEC

Steroid Hormone Regulation and Prognostic Value of the Human Kallikrein Gene 14 in Ovarian Cancer

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Detection and diversity of a putative novel heterogeneous polymorphic proline-glycine repeat (Pgr) protein in the footrot pathogen Dichelobacter nodosus

Dichelobacter nodosus, a Gram-negative anaerobic bacterium, is the essential causative agent of footrot in sheep. Currently, depending on the clinical presentation in the field, footrot is described as benign or virulent; D. nodosus strains have also been classified as benign or virulent, but this designation is not always consistent with clinical disease. The aim of this study was to determine the diversity of the pgr gene, which encodes a putative proline-glycine repeat protein (Pgr). The pgr gene was present in all 100 isolates of D. nodosus that were examined and, based on sequence analysis had two variants, pgrA and pgrB. In pgrA, there were two coding tandem repeat regions, R1 and R2: different strains had variable numbers of repeats within these regions. The R1 and R2 were absent from pgrB. Both variants were present in strains from Australia, Sweden and the UK, however, only pgrB was detected in isolates from Western Australia. The pgrA gene was detected in D. nodosus from tissue samples from two flocks in the UK with virulent footrot and only pgrB from a flock with no virulent or benign footrot for >10 years. Bioinformatic analysis of the putative PgrA protein indicated that it contained a collagen-like cell surface anchor motif. These results suggest that the pgr gene may be a useful molecular marker for epidemiological studies

Predictors of survival in sporadic Creutzfeldt-Jakob disease and other human transmissible spongiform encephalopathies

A collaborative study of human transmissible spongiform encephalopathies has been carried out from 1993 to 2000 and includes data from 10 national registries, the majority in Western Europe. In this study, we present analyses of predictors of survival in sporadic (n = 2304), iatrogenic (n = 106) and variant Creutzfeldt-Jakob disease (n = 86) and in cases associated with mutations of the prion protein gene (n = 278), including Gerstmann-Sträussler-Scheinker syndrome (n = 24) and fatal familial insomnia (n = 41). Overall survival for each disease type was assessed by the Kaplan-Meier method and the multivariate analyses by the Cox proportional hazards model. In sporadic disease, longer survival was correlated with younger age at onset of illness, female gender, codon 129 heterozygosity, presence of CSF 14-3-3 protein and type 2a prion protein type. The ability to predict survival based on patient covariates is important for diagnosis and counselling, and the characterization of the survival distributions, in the absence of therapy, will be an important starting point for the assessment of potential therapeutic agents in the futur