Observations of Radar Backscatter at Ku and C Bands in the Presence of Large Waves during the Surface Wave Dynamics Experiment

Ocean radar backscatter in the presence of large waves is investigated using data acquired with the Jet Propulsion Laboratory NUSCAT radar at Ku band for horizontal and vertical polarizations and the University of Massachusetts CSCAT radar at C band for vertical polarization during the Surface Wave Dynamics Experiment. Off-nadir backscatter data of ocean surfaces were obtained in the presence of large waves with significant wave height up to 5.6 m. In moderate-wind cases, effects of large waves are not detectable within the measurement uncertainty and no noticeable correlation between backscatter coefficients and wave height is found. Under high-wave light-wind conditions, backscatter is enhanced significantly at large incidence angles with a weaker effect at small incidence angles. Backscatter coefficients in the wind speed range under consideration are compared with SASS-2 (Ku band), CMOD3-H1 (C band), and Plant's model results which confirm the experimental observations. Variations of the friction velocity, which can give rise to the observed backscatter behaviors in the presence of large waves, are presented

NMR structural analysis of DNA recognition by a novel Myb1 DNA-binding domain in the protozoan parasite Trichomonas vaginalis

The transcription regulator, tvMyb1, is the first Myb family protein identified in Trichomonas vaginalis. Using an electrophoretic mobility shift assay, we defined the amino-acid sequence from Lys35 to Ser141 (tvMyb135–141) as the minimal DNA-binding domain, encompassing two Myb-like DNA-binding motifs (designated as R2 and R3 motifs) and an extension of 10 residues at the C-terminus. NMR solution structures of tvMyb135–141 show that both the R2 and R3 motifs adopt helix-turn-helix conformations while helix 6 in the R3 motif is longer than its counterpart in vertebrate Myb proteins. The extension of helix 6 was then shown to play an important role in protein stability as well as in DNA-binding activity. The structural basis for the tvMyb135–141/DNA interaction was investigated using chemical shift perturbations, residual dipolar couplings, DNA specificity data and data-driven macromolecular docking by HADDOCK. Our data indicate that the orientation between R2 and R3 motifs dramatically changes upon binding to DNA so as to recognize the DNA major groove through a number of key contacts involving residues in helices 3 and 6. The tvMyb135–141/DNA complex model furthers our understanding of DNA recognition by Myb proteins and this approach could be applied in determining the complex structures involving proteins with multiple domains

Women with endometriosis have higher comorbidities: Analysis of domestic data in Taiwan

AbstractEndometriosis, defined by the presence of viable extrauterine endometrial glands and stroma, can grow or bleed cyclically, and possesses characteristics including a destructive, invasive, and metastatic nature. Since endometriosis may result in pelvic inflammation, adhesion, chronic pain, and infertility, and can progress to biologically malignant tumors, it is a long-term major health issue in women of reproductive age. In this review, we analyze the Taiwan domestic research addressing associations between endometriosis and other diseases. Concerning malignant tumors, we identified four studies on the links between endometriosis and ovarian cancer, one on breast cancer, two on endometrial cancer, one on colorectal cancer, and one on other malignancies, as well as one on associations between endometriosis and irritable bowel syndrome, one on links with migraine headache, three on links with pelvic inflammatory diseases, four on links with infertility, four on links with obesity, four on links with chronic liver disease, four on links with rheumatoid arthritis, four on links with chronic renal disease, five on links with diabetes mellitus, and five on links with cardiovascular diseases (hypertension, hyperlipidemia, etc.). The data available to date support that women with endometriosis might be at risk of some chronic illnesses and certain malignancies, although we consider the evidence for some comorbidities to be of low quality, for example, the association between colon cancer and adenomyosis/endometriosis. We still believe that the risk of comorbidity might be higher in women with endometriosis than that we supposed before. More research is needed to determine whether women with endometriosis are really at risk of these comorbidities

A Highly Organized Structure Mediating Nuclear Localization of a Myb2 Transcription Factor in the Protozoan Parasite Trichomonas vaginalis ▿ †

Nuclear proteins usually contain specific peptide sequences, referred to as nuclear localization signals (NLSs), for nuclear import. These signals remain unexplored in the protozoan pathogen, Trichomonas vaginalis. The nuclear import of a Myb2 transcription factor was studied here using immunodetection of a hemagglutinin-tagged Myb2 overexpressed in the parasite. The tagged Myb2 was localized to the nucleus as punctate signals. With mutations of its polybasic sequences, 48KKQK51 and 61KR62, Myb2 was localized to the nucleus, but the signal was diffusive. When fused to a C-terminal non-nuclear protein, the Myb2 sequence spanning amino acid (aa) residues 48 to 143, which is embedded within the R2R3 DNA-binding domain (aa 40 to 156), was essential and sufficient for efficient nuclear import of a bacterial tetracycline repressor (TetR), and yet the transport efficiency was reduced with an additional fusion of a firefly luciferase to TetR, while classical NLSs from the simian virus 40 T-antigen had no function in this assay system. Myb2 nuclear import and DNA-binding activity were substantially perturbed with mutation of a conserved isoleucine (I74) in helix 2 to proline that altered secondary structure and ternary folding of the R2R3 domain. Disruption of DNA-binding activity alone by point mutation of a lysine residue, K51, preceding the structural domain had little effect on Myb2 nuclear localization, suggesting that nuclear translocation of Myb2, which requires an ordered structural domain, is independent of its DNA binding activity. These findings provide useful information for testing whether myriad Mybs in the parasite use a common module to regulate nuclear import