Pullulanase (EC 3.2.1.41) is a well known starch-debranching enzyme that catalyzes the cleavage of α-1,6-glycosidic linkages in α-glucans such as starch and pullulan. Crystal structures of a type I pullulanase from Paenibacillus barengoltzii (PbPulA) and of PbPulA in complex with maltopentaose (G5), maltohexaose (G6)/α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) were determined in order to better understand substrate binding to this enzyme. PbPulA belongs to glycoside hydrolase (GH) family 13 subfamily 14 and is composed of three domains (CBM48, A and C). Three carbohydrate-binding sites identified in PbPulA were located in CBM48, near the active site and in domain C, respectively. The binding site in CBM48 was specific for β-CD, while that in domain C has not been reported for other pullulanases. The domain C binding site had higher affinity for α-CD than for G6; a small motif (FGGEH) seemed to be one of the major determinants for carbohydrate binding in this domain. Structure-based mutations of several surface-exposed aromatic residues in CBM48 and domain C had a debilitating effect on the activity of the enzyme. These results suggest that both CBM48 and domain C play a role in binding substrates. The crystal forms described contribute to the understanding of pullulanase domain–carbohydrate interactions.

Bipasha Dey and Richa Rikhy

Cell shape morphogenesis from spherical to polygonal occurs in epithelial cell formation in metazoan embryogenesis. In syncytial Drosophila embryos, the plasma membrane incompletely surrounds each nucleus and is organized as a polygonal epithelial-like array. Each cortical syncytial division cycle shows circular to polygonal plasma membrane transition along with furrow extension between adjacent nuclei from interphase to metaphase. In this study, we assess the relative contribution of DE-cadherin and Myosin II at the furrow for polygonal shape transition. We show that polygonality initiates during each cortical syncytial division cycle when the furrow extends from 4.75 to 5.75 µm. Polygon plasma membrane organization correlates with increased junctional tension, increased DE-cadherin and decreased Myosin II mobility. DE-cadherin regulates furrow length and polygonality. Decreased Myosin II activity allows for polygonality to occur at a lower length than controls. Increased Myosin II activity leads to loss of lateral furrow formation and complete disruption of polygonal shape transition. Our studies show that DE-cadherin-Myosin II balance regulates an optimal lateral membrane length during each syncytial cycle for polygonal shape transition.

Sanjeev Chavan Nayak and Vegesna Radha

C3G (RapGEF1) plays a role in cell differentiation and is essential for early embryonic development in mice. In this study, we identify C3G as a centrosomal protein colocalizing with cenexin at the mother centriole in interphase cells. C3G interacts through its catalytic domain with cenexin, and they show interdependence for localization to the centrosome. C3G depletion caused a decrease in cellular cenexin levels. Centrosomal localization is lost as myocytes differentiate to form myotubes. Stable clone of cells depleted of C3G by CRISPR/Cas9 showed the presence of supernumerary centrioles. Overexpression of C3G, or a catalytically active deletion construct inhibited centrosome duplication. Cilia length is longer in C3G knockout cells, and the phenotype could be reverted upon reintroduction of C3G or its catalytic domain. Association of C3G with the basal body is dynamic, decreasing upon serum starvation, and increasing upon reentry into the cell cycle. C3G inhibits cilia formation and length dependent on its catalytic activity. We conclude that C3G inhibits centrosome duplication and maintains ciliary homeostasis, properties that may be important for its role in embryonic development.

Single-wavelength X-ray anomalous diffraction (SAD) is a frequently employed technique to solve the phase problem in X-ray crystallography. The precision and accuracy of recovered anomalous differences are crucial for determining the correct phases. Continuous rotation (CR) and inverse-beam geometry (IBG) anomalous data collection methods have been performed on tetragonal lysozyme and monoclinic survivin crystals and analysis carried out of how correlated the pairs of Friedel's reflections are after scaling. A multivariate Bayesian model for estimating anomalous differences was tested, which takes into account the correlation between pairs of intensity observations and incorporates the a priori knowledge about the positivity of intensity. The CR and IBG data collection methods resulted in positive correlation between I(+) and I(−) observations, indicating that the anomalous difference dominates between these observations, rather than different levels of radiation damage. An alternative pairing method based on near simultaneously observed Bijvoet's pairs displayed lower correlation and it was unsuccessful for recovering useful anomalous differences when using the multivariate Bayesian model. In contrast, multivariate Bayesian treatment of Friedel's pairs improved the initial phasing of the two tested crystal systems and the two data collection methods.

The post Conservators challenged by contemporary artworks at the Hirshhorn Museum appeared first on Smithsonian Insider.

Join National Zoo Conservation Biologist Brian Gratwicke in his work to save Panama's amphibians from extinction. You can also catch up on his dispatches from the field on the Panamanian Amphibian Rescue and Conservation Project's blog: http://amphibianrescue.org/

The post Meet our Scientist: Brian Gratwicke, Amphibian Avenger appeared first on Smithsonian Insider.

What’s an Asian small-clawed otter’s favorite enrichment toy? Anything it can get its paws on! This species’ dexterous, partially-webbed digits are adept at feeling for […]

The post Otterly engaging: Zoo enrichment appeared first on Smithsonian Insider.

Despite many laws to protect it, a new survey reveals wild ginseng in Maryland is on the decline.

The post Wild ginseng in steep decline in Maryland, survey reveals: Q&A with Smithsonian botanist Christopher Puttock appeared first on Smithsonian Insider.

Engineers shouldn’t have to reinvent the wheel—or wings, or sonar systems—when mother nature has already done much of the heavy design work. In fact, finding […]

The post Next Engineering Revolution Is Hiding in Museum Collections appeared first on Smithsonian Insider.

Attempting to display the contents of an HDF5 file containing fixed-length UTF-8 encoded strings results in an unexpected error in MATLAB.

For example, the following code

  h5disp('myHDF5FileWithFixedLenUTF8Strings.h5')

returns this error:

Error using h5infoc
UTF-8 encoding is only supported for variable length strings.

Error in h5info (line 108)
hinfo = h5infoc(filename,location, useUtf8);

Error in h5disp>display_hdf5 (line 121)
hinfo = h5info(options.Filename,options.Location);

Error in h5disp (line 99)
display_hdf5(options);

Apr 9, 2020; 133:jcs246264-jcs246264
FIRST PERSON

Focused attention by world leaders is needed to address the substantial challenges posed by disposal of spent nuclear fuel from reactors and high-level radioactive waste from processing such fuel for military or energy purposes.

As the recent spread of West Nile virus and the anthrax scare of 2001 dramatically illustrate, America faces a variety of new health challenges in the 21st century, along with a number of persistent problems, such as racial disparities in health status and care delivery.

High schools that successfully engage students in learning have many things in common.

The U.S. National Academy of Engineering (NAE) today announced the grand challenges for engineering in the 21st century. A diverse committee of experts from around the world, convened at the request of the U.S. National Science Foundation, revealed 14 challenges that, if met, would improve how we live.

Many U.S. farmers who grow genetically engineered (GE) crops are realizing substantial economic and environmental benefits -- such as lower production costs, fewer pest problems, reduced use of pesticides, and better yields -- compared with conventional crops, says a new report from the National Research Council.

The National Academy of Engineering (NAE) has elected 67 new members and 11 foreign associates, announced NAE President C.D. (Dan) Mote Jr. today. This brings the total U.S. membership to 2,250 and the number of foreign associates to 214.

Young adults ages 18-26 should be viewed as a separate subpopulation in policy and research, because they are in a critical period of development when successes or failures could strongly affect the trajectories of their lives, says a new report from the Institute of Medicine and National Research Council.

Today the science academies of the G7 countries and seven additional academies issued three joint statements to their respective governments to inform discussions during the G7 summit to be held in May in Japan, as well as ongoing policymaking.

An extensive study by the National Academies of Sciences, Engineering, and Medicine has found that new technologies in genetic engineering and conventional breeding are blurring the once clear distinctions between these two crop-improvement approaches.

The U.S. Agency for International Development should speed its transformation into a global leader and catalyst in applying science, technology and innovation to the challenges facing developing countries, says a new report from the National Academies of Sciences, Engineering, and Medicine.

While workers in the engineering technology (ET) field play an important role in supporting U.S. technical infrastructure and the country’s capacity for innovation, there is little awareness of ET as a field of study or category of employment in the U.S., says a new report from the National Academy of Engineering.

Despite their potential, many English learners (ELs) -- who account for more than 9 percent of K-12 enrollment in the U.S. -- lag behind their English-speaking monolingual peers in educational achievement, in part because schools do not provide adequate instruction and social-emotional support to acquire English proficiency or access to academic subjects at the appropriate grade level, says a new report from the National Academies of Sciences, Engineering, and Medicine.

The National Academies Committee on Genetically Engineered Crops - Past Experiences and Future Prospects authored an almost 600-page landmark report, released in May 2016. It was perhaps the most comprehensive analysis of genetically engineered crops to date.

Despite broad understanding of volcanoes, our ability to predict the timing, duration, type, size, and consequences of volcanic eruptions is limited, says a new report by the National Academies of Sciences, Engineering, and Medicine.

The U.S. National Academies of Sciences, Engineering, and Medicine are now serving as the host for the InterAcademy Partnership for Research (IAP-R) secretariat.

The National Academy of Engineering announced today that the 2018 Charles Stark Draper Prize for Engineering will be awarded to Bjarne Stroustrup.

The National Institute for Occupational Safety and Health (NIOSH) should lead a collaborative effort with the U.S. Bureau of Labor Statistics (BLS), Occupational Safety and Health Administration (OSHA), and the states to establish and strengthen regional occupational safety and health surveillance programs, says a new report by the National Academies of Sciences, Engineering, and Medicine.

High-quality early care and education (ECE) is critical to positive child development and has the potential to generate economic returns, but the current financing structure of ECE leaves many children without access to high-quality services and does little to strengthen the ECE workforce, says a new report from the National Academies of Sciences, Engineering, and Medicine.

A new report from the National Academies of Sciences, Engineering, and Medicine calls for a series of substantial reforms to strengthen the U.S. biomedical research system for the next generation of scientists.

The National Academy of Engineering today announced the winners of its 2018 EngineerGirl essay competition.

Sexual harassment in science, engineering, and medicine diminishes the integrity of the U.S. research enterprise.

A new report from the National Academies of Sciences, Engineering, and Medicine recommends substantial changes to U.S. graduate education in science, technology, engineering, and mathematics (STEM) in order to meet the evolving needs of students, the scientific enterprise, and the nation.

To enable public transit agencies to engage in more rigorous and effective safety planning, their safety planning records should not be admissible as evidence in civil litigation, says a new report from the National Academies of Sciences, Engineering, and Medicine.

The National Academies of Sciences, Engineering, and Medicine are launching the “New Voices in Sciences, Engineering, and Medicine” initiative to identify outstanding early-career science, engineering, and medicine (SEM) leaders.

The U.S. Environmental Protection Agency has issued a proposed rule for strengthening transparency in regulatory science (April 30, 2018, 83 Federal Register 18768), which stipulates that EPA will ensure that the data and models underlying the pivotal science that informs significant regulatory actions are made publicly available, in a format that allows for outside analysis and validation.

A new report from the National Academies of Sciences, Engineering, and Medicine identifies the most promising scientific breakthroughs that are possible to achieve in the next decade to increase the U.S. food and agriculture system’s sustainability, competitiveness, and resilience.

The National Academies Keck Futures Initiative (NAKFI) is pleased to announce the recipients of three $500,000 NAKFI Challenge awards. A 15-year, $40 million dollar program funded by the W.M. Keck Foundation, NAKFI was initiated in 2003 to break down barriers between fields and to promote interdisciplinary research.

The National Academy of Engineering (NAE) 2019 nominating committee1 has recommended John L. Anderson, President Emeritus and distinguished professor of chemical engineering at the Illinois Institute of Technology (Illinois Tech), to stand as the sole candidate2 for the NAE presidency.

On Sunday, Sept. 30, during its 2018 annual meeting, the National Academy of Engineering (NAE) will present two awards for extraordinary impact on the engineering profession.

The winners of the sixth annual D.C. Public Health Case Challenge were announced at this year’s National Academy of Medicine (NAM) Annual Meeting.

A shift is needed in how science, technology, engineering, and mathematics (STEM) subjects are taught to students in grades K-12 who are learning English, says a new report from the National Academies of Sciences, Engineering, and Medicine.

Centering science instruction around investigation and design can improve learning in middle and high schools and help students make sense of phenomena in the world around them.

Over the next several decades as the global population grows, society will be faced with pressing challenges such as providing reliable supplies of food and water, diminishing climate change and adapting to its impacts, and building healthy, resilient cities.

A new report from the National Academies of Sciences, Engineering, and Medicine offers guidance to the U.S. Environmental Protection Agency to inform the next revision of a permit program that requires industries to manage stormwater to minimize discharges of pollutants to the environment.

When John L. Anderson, president emeritus and distinguished professor of chemical engineering at the Illinois Institute of Technology, was first elected to the National Academy of Engineering almost 30 years ago, he remembers being deeply honored and excited about how the recognition would help his career.

International thought leaders will join the next generation of engineers in London from Sept. 16 to 18 for the Global Grand Challenges Summit 2019. The summit aims to help inspire and equip future engineering leaders to address the rapidly evolving challenges of an unpredictable world.

For some patients, the ability to participate in a clinical trial from the comfort of one’s home is becoming a reality.