TASK DEFINITION: In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
PROBLEM: Context: Primary pneumonic plague is a rare but often fatal form of Yersinia pestis infection that results from direct inhalation of bacteria and is potentially transmissible from person to person. We describe a case of primary pneumonic plague in a wildlife biologist who was found deceased in his residence 1 week after conducting a necropsy on a mountain lion.', "To determine cause of death, a postmortem examination was conducted, and friends and colleagues were interviewed. Physical evidence was reviewed, including specimens from the mountain lion and the biologist's medical chart, camera, and computer. Human and animal tissues were submitted for testing. Persons in close contact (within 2 meters) to the biologist after he had developed symptoms were identified and offered chemoprophylaxis.", 'The biologist conducted the necropsy in his garage without the use of personal protective equipment. Three days later, he developed fever and hemoptysis and died approximately 6 days after exposure. Gross examination showed consolidation and hemorrhagic fluid in the lungs; no buboes were noted. Plague was diagnosed presumptively by polymerase chain reaction and confirmed by culture. Tissues from the mountain lion tested positive for Y. pestis, and isolates from the biologist and mountain lion were indistinguishable by pulsed-field gel electrophoresis. Among 49 contacts who received chemoprophylaxis, none developed symptoms consistent with plague.\Question: Do primary pneumonic plague contracted from a mountain lion carcass?

SOLUTION: The biologist likely acquired pneumonic plague through inhalation of aerosols generated during postmortem examination of an infected mountain lion. Enhanced awareness of zoonotic diseases and appropriate use of personal protective equipment are needed for biologists and others who handle wildlife.

PROBLEM: Context: Chromatin epigenetics participate in control of gene expression during metazoan development. DNA methylation and post-translational modifications (PTMs) of histones have been extensively characterised in cell types present in, or derived from, mouse embryos. In embryonic stem cells (ESCs) derived from blastocysts, factors involved in deposition of epigenetic marks regulate properties related to self-renewal and pluripotency. In the germ lineage, changes in histone PTMs and DNA demethylation occur during formation of the primordial germ cells (PGCs) to reset the epigenome of the future gametes. Trimethylation of histone H3 on lysine 27 (H3K27me3) by Polycomb group proteins is involved in several epigenome-remodelling steps, but it remains unclear whether these epigenetic features are conserved in non-mammalian vertebrates. To investigate this question, we compared the abundance and nuclear distribution of the main histone PTMs, 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) in chicken ESCs, PGCs and blastodermal cells (BCs) with differentiated chicken ESCs and embryonic fibroblasts. In addition, we analysed the expression of chromatin modifier genes to better understand the establishment and dynamics of chromatin epigenetic profiles.', 'The nuclear distributions of most PTMs and 5hmC in chicken stem cells were similar to what has been described for mammalian cells. However, unlike mouse pericentric heterochromatin (PCH), chicken ESC PCH contained high levels of trimethylated histone H3 on lysine 27 (H3K27me3). In differentiated chicken cells, PCH was less enriched in H3K27me3 relative to chromatin overall. In PGCs, the H3K27me3 global level was greatly reduced, whereas the H3K9me3 level was elevated. Most chromatin modifier genes known in mammals were expressed in chicken ESCs, PGCs and BCs. Genes presumably involved in de novo DNA methylation were very highly expressed. DNMT3B and HELLS/SMARCA6 were highly expressed in chicken ESCs, PGCs and BCs compared to differentiated chicken ESCs and embryonic fibroblasts, and DNMT3A was strongly expressed in ESCs, differentiated ESCs and BCs.\Question: Do chicken embryonic stem cells and primordial germ cells display different heterochromatic histone marks than their mammalian counterparts?

SOLUTION: Chicken ESCs and PGCs differ from their mammalian counterparts with respect to H3K27 methylation. High enrichment of H3K27me3 at PCH is specific to pluripotent cells in chicken. Our results demonstrate that the dynamics in chromatin constitution described during mouse development is not universal to all vertebrate species.

PROBLEM: Context: To establish a cell model by chronically infecting human gastric epithelial cells with H.pylori, and to determine the effect of chronic H.pylori infection on apoptosis of gastric epithelial cells.', 'Human non-tumor gastric epithelial cells GES-1 were cocultured with an H.pylori strain SS1 for 16 weeks, in order to obtain GES-1 "model" cells. Biological characteristics of the model cells including growth, adherence and clone formation were determined. Apoptosis of the "model" cells in response to apoptosis inducers such as H.pylori and other enterobacteria and agents commonly used in the chemotherapy of gastric cancer were measured by flow cytometry.', 'A cell model of human gastric epithelial cells with chronic H.pylori infection (GES-1 model cells) was successfully established. Apoptosis was dramatically decreased in the "model" cells with and without stimulation by H.pylori and other enterobacteria and some chemotherapeutic agents.\Question: Does [ Chronic Helicobacter pylori infection induce apoptosis-resistance in gastric epithelial cells ]?

SOLUTION:
Chronic H.pylori infection induces apoptosis resistance in gastric epithelial cells, which may increase the risk of the development of gastric cancer.