Population structure and adaptation of a bacterial pathogen in California grapevines

Xylella fastidiosa subsp. fastidiosa causes Pierce's disease of grapevine (PD) and has been present in California for over a century. A singly introduced genotype spread across the state causing large outbreaks and damaging the grapevine industry. This study presents 122 X. fastidiosa subsp. fastidiosa genomes from symptomatic grapevines, and explores pathogen genetic diversity associated with PD in California. A total of 5218 single-nucleotide polymorphisms (SNPs) were found in the dataset. Strong population genetic structure was found; isolates split into five genetic clusters divided into two lineages. The core/soft-core genome constituted 41.2% of the total genome, emphasizing the high genetic variability of X. fastidiosa genomes. An ecological niche model was performed to estimate the environmental niche of the pathogen within California and to identify key climatic factors involved in dispersal. A landscape genomic approach was undertaken aiming to link local adaptation to climatic factors. A total of 18 non-synonymous polymorphisms found to be under selective pressures were correlated with at least one environmental variable highlighting the role of temperature, precipitation and elevation on X. fastidiosa adaptation to grapevines in California. Finally, the contribution to virulence of three of the genes under positive selective pressure and of one recombinant gene was studied by reverse genetics.     

Recommendations on how to provide cardiac rehabilitation services during the COVID-19 pandemic

The ongoing coronavirus disease 2019 (COVID-19) crisis is having a large impact on acute and chronic cardiac care. Due to public health measures and t     

The belated US FDA approval of the adenosine A2A receptor antagonist istradefylline for treatment of Parkinson’s disease

Purinergic Signalling - After more than two decades of preclinical and clinical studies, on August 27, 2019, the US Food and Drug Administration (FDA) approved the adenosine A2A receptor antagonist...     

Establishment and in vitro morphogenesis of sapucaia explants (Lecythidaceae)

Lecythis pisonis Cambess, popularly known as sapucaia, has great economic and socio-environmental potential. The objective of this study was to evaluate the establishment and in vitro morphogenesis of L. pisonis under the effect of disinfecting agents, plant growth regulators, and thermal stress. The study was divided into three experiments: (i) development of the disinfection protocol by testing different concentrations and times of exposure to sodium hypochlorite (NaOCl) and different concentrations and methods of amoxicillin application, (ii) in vitro budding induction by testing different concentrations of 6-benzylaminopurine (BAP) or kinetin (KIN) supplemented to Woody Plant Medium (WPM) and Murashige and Skoog (MS) culture media, and (iii) in vitro formation from plantlets by analyzing different concentrations of indole-3-butyric acid (IBA) with different exposure times to a thermal stress of 40°C. The disinfection of stem segments was effective using 3% NaOCl and 3.0 g L⁻¹ amoxicillin solution. MS culture medium supplemented with 0.25 mg L⁻¹ BAP induced more shoots in vitro. One milligram per liter IBA promoted greater rooting in vitro, and it is not necessary for thermal stress tolerance.

     

Lack of adequate seed supply is a major bottleneck for effective ecosystem restoration in Chile: friendly amendment to Bannister et al. (2018)

We argue that the need for a quality seed supply chain is a major bottleneck for the restoration of Chile's native ecosystems, thus supplementing the list of bottlenecks proposed by Bannister et al. in 2018. Specifically, there is a need for defining seed transfer zones, developing standards and capacities for properly collecting and storing seeds, reducing information gaps on seed physiology and longevity, and implementing an efficient seed supply chain with certification of seed origin and quality. Without such capacities, countries are unlikely to meet their restoration commitments. Although we focus on bottlenecks in Chile, the issues we raise are relevant to other countries and thus the global agenda for ecological restoration.     

Partial Evaluation of Autochthonous Probiotic Potential of the Gut Microbiota of Seriola lalandi

Seriola lalandi is an economically important species that is globally distributed in temperate and subtropical marine waters. Aquaculture production of this species has had problems associated with intensive fish farming, such as disease outbreaks or nutritional deficiencies causing high mortality. Intestinal microbiota are involved in many processes that benefit a host, such as disease control, stimulation of the immune response, and the promotion of nutrient metabolism. The aim of this study is to evaluate the in vitro probiotic properties of bacteria isolated from the intestinal content of wild Seriola lalandi. The probiotic potential was evaluated in terms of (i) the antimicrobial activity against vibrios causing outbreaks in farmed fish; (ii) the ability to stimulate genes related to an innate immune response in fish; and (iii) antibiotic resistance. Nineteen isolates identified as Pseudomonas, Shewanella, Psychrobacter, and Acinetobacter showed antimicrobial activity and significant relative expression of cytokines, serum amyloid A protein (SAA), hepcidin, and lysozyme. A positive correlation was observed between the levels of expression and the bacterial load after 24 h of exposure. Pseudomonas isolates showed a level of antibiotic resistance. In conclusion, isolates of the genera Shewanella, Psychrobacter, and Acinetobacter could serve as potential probiotics in S. lalandi culture.