Germinación in vitro e inducción de callo en Rubus adenotrichus Schltdl.

Una alternativa para resolver problemas de dormancia, obtención masiva de plantas y biomoléculas de interés es el cultivo in vitro, el objetivo de este trabajo fue inducir la germinación y establecer el cultivo de callo deRubus adenotrichus. Se probaron tres métodos de escarificación: 1) inmersión en ácido sulfúrico (30 y 60 min), 2) inmersión en hipoclorito de sodio (72 h) y 3) remoción de la cubierta de la semilla, este último tratamiento fue el mejor, generando un 68% de porcentaje de germinación, en medio Murashige Skoog (MS) sin reguladores. Las plántulas obtenidas tuvieron un desarrollo similar al de las plantas silvestres. Para la inducción de callo, se emplearon hojas de plantas silvestres como explantes y fueron colocadas en dos tipos de medio: MS, con 1 mg/L de ácido naftalenacético y 0.5 mg/L cinetina) y Woody Plant Medium (WPM) con 0.5 mg/L de ácido 2,4-diclorofenoxiacético y 0.75 mg/L de cinetina. En ambos medios se desarrolló un callo friable y pigmentado. El proceso de escarifi cación es fundamental para la germinación de esta especie. El empleo de los medios MS y WPM, con los reguladores adicionados son promotores de la producción de callos friables

A Model for the Development of the Rhizobial and Arbuscular Mycorrhizal Symbioses in Legumes and Its Use to Understand the Roles of Ethylene in the Establishment of these two Symbioses

We propose a model depicting the development of nodulation and arbuscular mycorrhizae. Both processes are dissected into many steps, using Pisum sativum L. nodulation mutants as a guideline. For nodulation, we distinguish two main developmental programs, one epidermal and one cortical. Whereas Nod factors alone affect the cortical program, bacteria are required to trigger the epidermal events. We propose that the two programs of the rhizobial symbiosis evolved separately and that, over time, they came to function together. The distinction between these two programs does not exist for arbuscular mycorrhizae development despite events occurring in both root tissues. Mutations that affect both symbioses are restricted to the epidermal program. We propose here sites of action and potential roles for ethylene during the formation of the two symbioses with a specific hypothesis for nodule organogenesis. Assuming the epidermis does not make ethylene, the microsymbionts probably first encounter a regulatory level of ethylene at the epidermis–outermost cortical cell layer interface. Depending on the hormone concentrations there, infection will either progress or be blocked. In the former case, ethylene affects the cortex cytoskeleton, allowing reorganization that facilitates infection; in the latter case, ethylene acts on several enzymes that interfere with infection thread growth, causing it to abort. Throughout this review, the difficulty of generalizing the roles of ethylene is emphasized and numerous examples are given to demonstrate the diversity that exists in plants

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Germinación in vitro e inducción de callo en Rubus adenotrichus Schltdl.

Una alternativa para resolver problemas de dormancia, obtención masiva de plantas y biomoléculas de interés es el cultivo in vitro, el objetivo de este trabajo fue inducir la germinación y establecer el cultivo de callo deRubus adenotrichus. Se probaron tres métodos de escarificación: 1) inmersión en ácido sulfúrico (30 y 60 min), 2) inmersión en hipoclorito de sodio (72 h) y 3) remoción de la cubierta de la semilla, este último tratamiento fue el mejor, generando un 68% de porcentaje de germinación, en medio Murashige Skoog (MS) sin reguladores. Las plántulas obtenidas tuvieron un desarrollo similar al de las plantas silvestres. Para la inducción de callo, se emplearon hojas de plantas silvestres como explantes y fueron colocadas en dos tipos de medio: MS, con 1 mg/L de ácido naftalenacético y 0.5 mg/L cinetina) y Woody Plant Medium (WPM) con 0.5 mg/L de ácido 2,4-diclorofenoxiacético y 0.75 mg/L de cinetina. En ambos medios se desarrolló un callo friable y pigmentado. El proceso de escarifi cación es fundamental para la germinación de esta especie. El empleo de los medios MS y WPM, con los reguladores adicionados son promotores de la producción de callos friables.</span

Epidemiology of intra-abdominal infection and sepsis in critically ill patients: “AbSeS”, a multinational observational cohort study and ESICM Trials Group Project

Purpose: To describe the epidemiology of intra-abdominal infection in an international cohort of ICU patients according to a new system that classifies cases according to setting of infection acquisition (community-acquired, early onset hospital-acquired, and late-onset hospital-acquired), anatomical disruption (absent or present with localized or diffuse peritonitis), and severity of disease expression (infection, sepsis, and septic shock). Methods: We performed a multicenter (n = 309), observational, epidemiological study including adult ICU patients diagnosed with intra-abdominal infection. Risk factors for mortality were assessed by logistic regression analysis. Results: The cohort included 2621 patients. Setting of infection acquisition was community-acquired in 31.6%, early onset hospital-acquired in 25%, and late-onset hospital-acquired in 43.4% of patients. Overall prevalence of antimicrobial resistance was 26.3% and difficult-to-treat resistant Gram-negative bacteria 4.3%, with great variation according to geographic region. No difference in prevalence of antimicrobial resistance was observed according to setting of infection acquisition. Overall mortality was 29.1%. Independent risk factors for mortality included late-onset hospital-acquired infection, diffuse peritonitis, sepsis, septic shock, older age, malnutrition, liver failure, congestive heart failure, antimicrobial resistance (either methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, extended-spectrum beta-lactamase-producing Gram-negative bacteria, or carbapenem-resistant Gram-negative bacteria) and source control failure evidenced by either the need for surgical revision or persistent inflammation. Conclusion: This multinational, heterogeneous cohort of ICU patients with intra-abdominal infection revealed that setting of infection acquisition, anatomical disruption, and severity of disease expression are disease-specific phenotypic characteristics associated with outcome, irrespective of the type of infection. Antimicrobial resistance is equally common in community-acquired as in hospital-acquired infection. © 2019, The Author(s)