Forest health in the Anthropocene: the emergence of a novel tree disease is associated with poplar cultivation.

Plant domestication and movement are large contributors to the success of new diseases. The introduction of new host species can result in accelerated evolutionary changes in pathogens, affecting long-established coevolutionary dynamics. This has been observed in poplars where severe epidemics of pathogens that were innocuous in their natural pathosystems occurred following host domestication. The North American fungus Sphaerulina musiva is responsible for endemic leaf spots on Populus deltoides. We show that the expansion of poplar cultivation resulted in the emergence of a new lineage of this pathogen that causes stem infections on a new host, P. balsamifera. This suggests a host shift since this is not a known host. Genome analysis of this emerging lineage reveals a mosaic pattern with islands of diversity separated by fixed genome regions, which is consistent with a homoploid hybridization event between two individuals that produced a hybrid swarm. Genome regions of extreme divergence and low diversity are enriched in genes involved in host-pathogen interactions. The specialization of this emerging lineage to a new host and its clonal propagation represents a serious threat to poplars and could affect both natural and planted forests. This work provides a clear example of the changes created by the intensification of tree cultivation that facilitate the emergence of specialized pathogens, jeopardizing the natural equilibrium between hosts and pathogens. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.

Factors associated with hospital admission and adverse outcome for COVID-19: Role of social factors and medical care.

BACKGROUND: Beyond sex, age, and various comorbidities, geographical origin and socioeconomic deprivation are associated with Coronavirus Disease (COVID-19) morbidity and mortality in the general population. We aimed to assess factors associated with severe forms of COVID-19 after a hospital emergency department visit, focusing on socioeconomic factors. METHODS: Patients with laboratory-confirmed COVID-19 attending the emergency department of Béclère Hospital (France) in March-April 2020 were included. Postal addresses were used to obtain two geographical deprivation indices at the neighborhood level. Factors associated with hospitalization and factors associated with adverse outcomes, i.e. mechanical ventilation or death, were studied using logistic and Cox analyses, respectively. RESULTS: Among 399 included patients, 321 were hospitalized. Neither geographical origin nor socioeconomic deprivation was associated with any of the outcomes. Being male, older, overweight or obese, diabetic, or having a neuropsychiatric disorder were independent risk factors for hospitalization. Among 296 patients hospitalized at Béclère Hospital, 91 experienced an adverse outcome. Older age, being overweight or obese, desaturation and extent of chest CT scan lesions>25% at admission (aHR: 2.2 [95% CI: 1.3-3.5]) and higher peak CRP levels and acute kidney failure (aHR: 2.0 [1.2-3.3]) during follow-up were independently associated with adverse outcomes, whereas treatment with hydrocortisone reduced the risk of mechanical ventilation or death by half (aHR: 0.5 [0.3-0.8]). CONCLUSION: No association between geographical origin or socioeconomic deprivation and the occurrence of a severe form of COVID-19 was observed in our population after arrival to the emergency department. Empirical corticosteroid use with hydrocortisone had a strong protective impact.

Graphene oxide-chloroquine nanoconjugate induce necroptotic death in A549 cancer cells through autophagy modulation.

AIM: Chloroquine (Chl) has shown its potential in cancer therapy and graphene oxide (GO) exhibited excellent tumor-targeting ability, biocompatibility and low toxicity. We have endeavored to conjugate Chl to GO sheets and investigated the nonproliferation action on A549 cell lines along with cell signaling pathways. MATERIALS & METHODS: Cellular toxicity, autophagic flux modulation and cell death mechanism induced by GO-Chl have been investigated on A549 cell lines. RESULTS & CONCLUSION: GO-Chl induces accumulation of autophagosomes (monodansylcadaverine staining, green fluorescence protein-tagged LC3 plasmid and transmission electron microscopy observations) in A549 cells through the blockade of autophagic flux that serves as scaffold for necrosome assembling and activates necroptotic cell death. GO-Chl nanoconjugate could be used as an effective cancer therapeutic agent, by targeting the autophagy necroptosis axis.

Minisatellite instability is found in colorectal tumours with mismatch repair deficiency.

Microsatellite instability (MSI) in colorectal tumours is demonstrated by PCR amplification of several different microsatellite loci. Minisatellites, which are repeats of longer sequences also found throughout the genome, may also be affected by tumorigenesis. Certain minisatellite alleles contain 2 types of similar repeat unit that are randomly interspersed. The interspersion pattern can be analysed by mapping variant repeat units along an amplified allele, minisatellite variant repeat unit mapping PCR (MVR-PCR). We have applied microsatellite analysis with 10 markers and MVR-PCR for locus D7S21 to 33 cases of colorectal neoplasia, 27 sporadic and 6 from patients suspected of having hereditary non-polyposis colorectal cancer (HNPCC). Of the 27 sporadic cases, 3 were MSI-high on microsatellite analysis and one MSI-low. Instability with MVR-PCR was observed, but only in the MSI-high cases. Four of the HNPCC patients had mismatch repair (MMR) gene mutations in either hMLH1 or hMSH2. All 4 had DNA instability by MVR-PCR, but only two of these had MSI (one high, one low). The other 2 of the 6 patients with suspected HNPCC were negative to mutation analysis. One had features strongly suggestive of HNPCC and was unstable by both microsatellite analysis (MSI-high) and by MVR-PCR. The other tumour, from an Amsterdam criteria positive kindred, did not demonstrate instability by any technique. Thus MVR-PCR detects DNA instability in MSI-high sporadic tumours and in those associated with HNPCC where MSI is observed. Further, in some MMR mutation positive cases MSI was not seen but instability was observed by MVR-PCR. MVR-PCR may be a valuable adjunct to the detection of MMR deficiency in colorectal tumours and it may allow new insights into the nature of DNA instability in this condition.