Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Context: Cysteine, a sulfur-containing amino acid, plays an important role in a variety of cellular functions such as protein biosynthesis, methylation, and polyamine and glutathione syntheses. In trypanosomatids, glutathione is conjugated with spermidine to form the specific antioxidant thiol trypanothione (T[SH]2) that plays a central role in maintaining intracellular redox homeostasis and providing defence against oxidative stress.', 'We cloned and characterised genes coding for a cystathionine β-synthase (CβS) and cysteine synthase (CS), key enzymes of the transsulfuration and assimilatory pathways, respectively, from the hemoflagellate protozoan parasite Trypanosoma rangeli.', 'Our results show that T. rangeli CβS (TrCβS), similar to its homologs in T. cruzi, contains the catalytic domain essential for enzymatic activity. Unlike the enzymes in bacteria, plants, and other parasites, T. rangeli CS lacks two of the four lysine residues (Lys26 and Lys184) required for activity. Enzymatic studies using T. rangeli extracts confirmed the absence of CS activity but confirmed the expression of an active CβS. Moreover, CβS biochemical assays revealed that the T. rangeli CβS enzyme also has serine sulfhydrylase activity.
Answer: These findings demonstrate that the RTS pathway is active in T. rangeli, suggesting that this may be the only pathway for cysteine biosynthesis in this parasite. In this sense, the RTS pathway appears to have an important functional role during the insect stage of the life cycle of this protozoan parasite.
Is transsulfuration an active pathway for cysteine biosynthesis in Trypanosoma rangeli?

Context: To investigate the effect of the X-linked immunodeficiency (Xid) B cell defect on the response to the cockroach allergen in mice.', 'Two cockroach allergen immunization and challenge protocols were employed to sensitize CBA/J wild-type and CBA/CaHN-btk(-/-)xid/J (Xid) mice. Blood and tissue samples were collected 24 and 48 hrs after the last intratracheal antigen challenge and were analyzed for several parameters of allergic inflammation.', 'Nearly equivalent amounts of serum IgE were detected in Xid and CBA/J mice after short-term antigen challenge despite the B cell deficiency in Xid mice. A decreased concentration of IgE was detected in CBA/J mice after repeated allergen challenges but not in the Xid mice. Correlating with the discrepancy in serum IgE levels, higher levels of IL-13, IL-5, IL-10 and CCL5 were measured in whole lung homogenates from allergen-challenged Xid mice compared to CBA/J mice. In addition, draining lymph node cells from Xid mice expressed elevated levels of IL-4, IL-5, IL-10 and IFNgamma mRNA compared to cells from CBA/J mice after in vitro culture with cockroach antigen. An increase in lung inflammation, interstitial eosinophilia and mucus production was also observed in allergen-challenged Xid mice. CD95L expression increased on B-1a cells following allergen challenge, which was accompanied by an increase in lung CD4(+) Th cell apoptosis in wild-type CBA/J mice. In contrast, Xid mice did not have an increase in CD4(+) T cell apoptosis following allergen challenge.
Answer: These data suggest a regulatory role for B-1a cells in reducing cytokine production, pulmonary inflammation, and CD4(+) T cell survival during cockroach allergen-induced airway inflammation.
Does deficiency of regulatory B cells increase allergic airway inflammation?

Context: The aim of this study was to investigate the influence of clinicopathological and biological characteristics on prognosis, disease free survival (DFS) and overall survival (OS), of very young patients (≤35 years of age) with breast cancer.', 'We retrospectively collected information of 150 women diagnosed with breast cancer, aged ≤35 years, who were operated and treated at two University Hospitals in Serbia between January 2009 and February 2011.', 'After a median follow up of 44 months patients ≤30 had shorter DFS and OS compared to patients aged 31-35 years (p=0.004 and p=0.037, respectively). The differences in DFS and OS were significant with decreased survival associated with higher tumor grade (p=0.005 and p=0.0001, respectively). Tumor size and number of positive nodes were predictors of outcome with decreased survival associated with higher tumor size (p=0.0019 for DFS and p<0.0001 for OS) and increasing number of nodes (p<0.0001 for both). HER 2 receptor did not seem to have a prognostic influence while patients with hormonal receptors (HRs) positive tumors had a better DFS (p=0.034) and OS (p=0.046) than those with HRs negative tumors. In univariate survival analysis, a significant difference in DFS (p=0.0003) and OS (p=0.0003) was found between patients with vs without lymphovascular invasion (LVI).
Answer: Diagnosis of breast cancer at very young age (<30) was associated with increased risk of death and shorter DFS than women aged 31-35. Negative impact on survival was seen in patients with presence of LVI, negative HRs and higher grade and stage at the time of presentation.

Do young age and pathological features predict breast cancer outcome - report from a dual Institution experience in Serbia?