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: Bacteria often form multicellular, organized communities known as biofilms, which protect cells from a variety of environmental stresses. During biofilm formation, bacteria secrete a species-specific matrix; in Bacillus subtilis biofilms, the matrix consists of protein polymers and exopolysaccharide. Many domesticated strains of B. subtilis have a reduced ability to form biofilms, and we conducted a two-month evolution experiment to test whether laboratory culturing provides selective pressure against biofilm formation in B. subtilis.', 'Bacteria grown in two-month-long batch culture rapidly diversified their biofilm-forming characteristics, exhibiting highly diverse colony morphologies on LB plates in the initial ten days of culture. Generally, this diversity decreased over time; however, multiple types of colony morphology remained in our final two-month-old populations, both under shaking and static conditions. Notably, while our final populations featured cells that produce less biofilm matrix than did the ancestor, cells overproducing biofilm matrix were present as well. We took a candidate-gene approach to identify mutations in the strains that overproduced matrix and found point mutations in the biofilm-regulatory gene sinR. Introducing these mutations into the ancestral strain phenocopied or partially phenocopied the evolved biofilm phenotypes.
Answer: Our data suggest that standard laboratory culturing conditions do not rapidly select against biofilm formation. Although biofilm matrix production is often reduced in domesticated bacterial strains, we found that matrix production may still have a fitness benefit in the laboratory. We suggest that adaptive specialization of biofilm-forming species can occur through mutations that modulate biofilm formation as in B. subtilis.
Is sinR a mutational target for fine-tuning biofilm formation in laboratory-evolved strains of Bacillus subtilis?

Context: To investigate the expression and clinical significance of programmed cell death 4 (PDCD4), a novel metabolism-associated gene, during polycystic ovary syndrome (PCOS) pathogenesis.', 'Case-control study.', 'University hospital.', 'A total of 77 PCOS patients and 67 healthy women as matched controls.', 'PDCD4 expression in peripheral blood mononuclear cells analyzed by quantitative real-time polymerase chain reaction, and apoptosis of granulosa cells (GCs) detected by flow cytometry, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and small-interfering RNA.', 'PDCD4 expression, body mass index (BMI), insulin 0, insulin 120, glucose 120, homeostasis model assessment for insulin resistance (HOMA-IR), homeostasis model assessment for -cell function (HOMA-), triglycerides, high-density lipoprotein (HDL), and GC apoptosis.', 'The PCOS patients had higher PDCD4 expression, but BMI was similar as matched with the obese group, which positively correlated with BMI, insulin 0, insulin 120, glucose 120, HOMA-IR, HOMA-, triglycerides and negatively correlated with HDL (P<.05). After metformin treatment, PDCD4 expression was distinctly down-regulated for the obese women with PCOS with insulin resistance. Compared with the healthy controls, the apoptosis percentage of GCs was higher in the PCOS group and was decreased by knocking down PDCD4. Furthermore, expression of proapotosis factor Bax and the Bax/Bcl-2 ratio were lower, whereas the expression of antiapoptosis factor Bcl-2 was increased. In a multivariate logistic regression analysis, the level of PDCD4 expression independently related to the odds of PCOS risk after controlling for estradiol and insulin 120 (odds ratio 1.318).
Answer: Our study suggests for the first time that higher PDCD4 expression might play an important role in PCOS pathogenesis by affecting obesity, insulin resistance, lipid metabolism disorders, and GC apoptosis.
Is higher PDCD4 expression associated with obesity , insulin resistance , lipid metabolism disorders , and granulosa cell apoptosis in polycystic ovary syndrome?

Context: To assess the reliability of thyroglobulin (Tg) as a marker of iodine status during pregnancy.', '299 women aged 30.5 4.8 years (mean SD) were studied.', 'In every subject, we measured urinary iodine concentration (UIC), serum thyrotropin (TSH), Tg, free thyroxine (fT4), Tg autoantibodies (TgAbs) and human chorionic gonadotropin (hCG) levels. We excluded samples with increased TgAbs from the analysis.', 'According to WHO criteria, the study population was iodine deficient in every trimester. Serum Tg levels did not differ during the three trimesters of pregnancy. Serum hCG levels fell significantly as pregnancies advanced. A weak, significantly negative correlation (limited to the 3rd trimester) was found between Tg and UIC ( = -0.187, p = 0.039). Serum fT4 decreased as pregnancies advanced and TSH increased. Serum fT4 was negatively correlated with TSH ( = -0.161, p = 0.006) and positively with hCG ( = +0.165, p = 0.005). The multiple regression equation of Tg based on hCG, TSH, UIC and trimester of pregnancy was significant but weak (F = 4.057, p = 0.003; R(2) = 0.055), with hCG as a significant predictor Tg (p for log hCG = 0.041).
Answer: Tg cannot be considered as a valid marker of iodine deficiency in pregnancy, at least in a mildly iodine-deficient environment. Further studies in a larger patient cohort with differences in iodine status, as well as studies on Tg changes after improving iodine status in pregnant women, are needed in order to corroborate these results.
Does serum Thyroglobulin Concentration be a Weak Marker of Iodine Status in a Pregnant Population with Iodine Deficiency?