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Genome evolution and adaptation in a long-term experiment with Escherichia coli
Barrick, Jeffrey E.,Yu, Dong Su,Yoon, Sung Ho,Jeong, Haeyoung,Oh, Tae Kwang,Schneider, Dominique,Lenski, Richard E.,Kim, Jihyun F. Macmillan Publishers Limited. All rights reserved 2009 Nature Vol.461 No.7268
The relationship between rates of genomic evolution and organismal adaptation remains uncertain, despite considerable interest. The feasibility of obtaining genome sequences from experimentally evolving populations offers the opportunity to investigate this relationship with new precision. Here we sequence genomes sampled through 40,000 generations from a laboratory population of Escherichia coli. Although adaptation decelerated sharply, genomic evolution was nearly constant for 20,000 generations. Such clock-like regularity is usually viewed as the signature of neutral evolution, but several lines of evidence indicate that almost all of these mutations were beneficial. This same population later evolved an elevated mutation rate and accumulated hundreds of additional mutations dominated by a neutral signature. Thus, the coupling between genomic and adaptive evolution is complex and can be counterintuitive even in a constant environment. In particular, beneficial substitutions were surprisingly uniform over time, whereas neutral substitutions were highly variable.
The 4th Industrial Revolution : The Human Dimension
Dr. Kirby BARRICK 한국직업자격학회 2017 한국직업자격학회 학술대회 Vol.2017 No.10
For more than two centuries, the world has experienced massive changes that have affected how we all live and work. First came the movement of peoples from foraging to farming, from agrarian to industrial, and from rural to urban. At a faster rate of development, the second revolution made mechanical power and mass production the norm. Then less than 50 years ago, the world was introduced to digital technology, automation, personal computers, and the internet. Now we have entered the fourth industrial revolution, where such phenomena as robotics, 3D printing, and massive virtual communities have encroached upon our lives. The implications for humankind are vast. While interest abounds in figuring out new technologies, we have been reminded by Klaus Schwab that “all of these new technologies are first and foremost tools made by people for people”. An important aspect of the fourth dimension is the need for human development through vocational education and training. Curricula, credentialing, social skills development, and public-private collaboration locally and globally are critical to preparing the current and next generations of the workforce with adequate 21st century skills.
A New Method for Estimating High-Frequency Radar Error Using Data from Central San Francisco Bay
Maxwell Hubbard,Donald Barrick,Newell Garfield,Jim Pettigrew,Carter Ohlmann,Matthew Gough 한국해양과학기술원 2013 Ocean science journal Vol.48 No.1
This study offers a new method for estimating High- Frequency (HF) radar surface current velocity error in data comparisons with other types of instrumentation. A new method is needed in order to remove the zero-mean random spatial and temporal fluctuations present in surface-current measurements from all sensors. Conventional methods for calculating radar error when comparing with another instrument have included their root mean square differences and scatter plots that provide correlation coefficient and slope/intercept of the regression line. It seems that a meaningful estimate of radar error should attempt to remove both sensors' zero mean random fluctuations, inasmuch as possible. We offer and compare a method that does this. The method was tested on data collected in the Central San Francisco Bay, where GPS surface-drifter deployments were conducted within the coverage of four 42 MHz radars over six days in October of 2008. Drifters were continuously deployed in these areas over the sampling days, providing 525 usable drifter measurements. Drifter and radar measurements were averaged into thirty-minute time bins. The three-day long-term averages from the sampling areas were then subtracted from the thirtyminute averages to remove biases associated with comparisons done with short, disjoint time-sample periods. These were then used to develop methods that give radar error or bias after the random fluctuations have been removed. Results for error estimates in this study are commensurate with others where random fluctuations have been filtered, suggesting they are valid. The estimated error for the radars in the SF Bay is low, ranging from -7.57 cm/s to 0.59 cm/s.
Song, Gyun Jee,Leslie, Kristen L,Barrick, Stacey,Mamonova, Tatyana,Fitzpatrick, Jeremy M,Drombosky, Kenneth W,Peyser, Noah,Wang, Bin,Pellegrini, Maria,Bauer, Philip M,Friedman, Peter A,Mierke, Dale F American Society for Biochemistry and Molecular Bi 2015 The Journal of biological chemistry Vol.290 No.5
<P>The regulation of the cell cycle by the ubiquitin-proteasome system is dependent on the activity of E3 ligases. Skp2 (S-phase kinase associated protein-2) is the substrate recognition subunit of the E3 ligase that ubiquitylates the cell cycle inhibitors p21(cip1) and p27(kip1) thus promoting cell cycle progression. Increased expression of Skp2 is frequently observed in diseases characterized by excessive cell proliferation, such as cancer and neointima hyperplasia. The stability and cellular localization of Skp2 are regulated by Akt, but the molecular mechanisms underlying these effects remain only partly understood. The scaffolding protein Ezrin-Binding Phosphoprotein of 50 kDa (EBP50) contains two PDZ domains and plays a critical role in the development of neointimal hyperplasia. Here we report that EBP50 directly binds Skp2 via its first PDZ domain. Moreover, EBP50 is phosphorylated by Akt on Thr-156 within the second PDZ domain, an event that allosterically promotes binding to Skp2. The interaction with EBP50 causes cytoplasmic localization of Skp2, increases Skp2 stability and promotes proliferation of primary vascular smooth muscle cells. Collectively, these studies define a novel regulatory mechanism contributing to aberrant cell growth and highlight the importance of scaffolding function of EBP50 in Akt-dependent cell proliferation.</P>