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.
--------
Question: Context: We study the Azospirillum brasilense tolerance to water deficit and the dynamics of adaptive process at the level of the membrane.', 'Azospirillum brasilense was exposed to polyethylene glycol (PEG) growth and PEG shock. Tolerance, phospholipids and fatty acid (FA) composition and membrane fluidity were determined. Azospirillum brasilense was able to grow in the presence of PEG; however, its viability was reduced. Cells grown with PEG showed membrane fluidity similar to those grown without, the lipid composition was modified, increasing phosphatidylcholine and decreasing phosphatidylethanolamine amounts. The unsaturation FAs degree was reduced. The dynamics of the adaptive response revealed a decrease in fluidity 20min after the addition of PEG, indicating that the PEG has a fluidizing effect on the hydrophobic region of the cell membrane. Fluidity returned to initial values after 60min of PEG exposure.\Question: Is reorganization of Azospirillum brasilense cell membrane mediated by lipid composition adjustment to maintain optimal fluidity during water deficit?

Answer: Azospirillum brasilense is able to perceive osmotic changes by changing the membrane fluidity. This effect is offset by changes in the composition of membrane phospholipid and FA, contributing to the homeostasis of membrane fluidity under water deficit.

Question: Context: To ascertain the predictive role of longitudinally acquired biochemical measures of cartilage turnover in relation to X-ray defined knee osteoarthritis (OAK), knee pain and functioning.', "This is a feasibility study based on 72 enrollees of the Michigan site of Study of Women's Health Across the Nation (SWAN), a longitudinal, population-based cohort study with 11 annual visits to characterize health at the mid-life. At visits in 1996, 1998 and 2007, radiographs were evaluated for the presence of OAK [>or=2 on the Kellgren and Lawrence (K-L) scale]. Knee pain and stiffness were assessed by interview. Functioning was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Cartilage oligomeric matrix protein (COMP) and Type II collagen telopeptides (CTX-II) were assayed in serum and urine samples collected on alternate years from 1997 to 2006. We related trajectories of the cartilage biochemical markers from these five time points to OAK severity (no OAK, K-L score<2; mild OAK, K-L score=2; moderate/severe OAK, K-L score=3 or 4), pain, stiffness, or functioning, using longitudinal non-linear mixed modeling.", 'The 2007 prevalence of X-ray defined OAK was 50% in these 72 women. Upward trajectories of COMP (P=0.02) and CTX-II (P=0.006) were associated with increased OAK severity and body size. COMP trajectories were associated with pain and stiffness, but not functioning. CTX-II trajectories were associated with stiffness scores, but not knee pain or functioning scores.\Question: Do longitudinal changes of serum COMP and urinary CTX-II predict X-ray defined knee osteoarthritis severity and stiffness in women?

Answer: Multiple, biennial measures of COMP or CTX-II taken over a 10-year period were predictive of subsequent OAK and knee stiffness.

Question: Context: The safety of a potential AIDS vaccine is an issue that will become critical at later stages of product development and needs to be addressed before it is too late.', 'In order to design safer vaccine, the HIV antigens, to be deployed in it, should be free of regions that are either present in human proteins or exhibit pronounced structural similarity to proteins responsible for important physiological functions.', 'The approach is based on the use of an original matrix predicting the antigenic similarity of amino acids. This mathematical approach developed by us was applied for identification of fragments with similarity to human proteins within potentially immunodominant regions of HIV proteins. A potential self-sensitization by viral quasispecies with variants of hypervariable V3 region, generated as a result of immune pressure on the immunodominant region of envelope, was considered in detail.', 'Viral fragments occurring in normal human proteins as well as regions exhibiting high similarity to proteins responsible for physiological homeostasis were identified in every HIV protein at a frequency higher than expected. Most such regions contained either T-cell (CD8(+) CTL or CD4(+) Helper) or B-cell epitopes, or both of them simultaneously. The gained knowledge was applied in designing a synthetic immunogen containing multiple CTL epitopes. The synthesis of series of chimeric peptides representing hypervariable region of V3 loop of HIV envelope, to be used as a multi-epitope or mixotope vaccine candidate, has been achieved. Such a vaccine could theoretically pre-empt any escape mutant borrowing from antigenic diversity of hypervariable region of V3 loop of HIV envelope.\Question: Is exclusion of HIV epitopes shared with human proteins prerequisite for designing safer AIDS vaccines?

Answer:
The epitopes shared by HIV and its host are likely to be implicated in the immunopathogenesis of AIDS through induction of cross-reacting effectors of the immune system. The prospect that 'house-keeping' immune mechanism can be foiled by molecular mimicry of HIV with physiologically important human proteins should be taken into consideration in safer vaccine design.