Recolonization of lake whitefish river spawning ecotypes and estimates of riverine larval production in Green Bay,Lake Michigan

Lake whitefish (Coregonus clupeaformis) within the waters of Green Bay, Lake Michigan have recently shown a substantial increase in abundance. Furthermore, after over 100 years of extirpation, adult lake whitefish are found spawning within major Wisconsin tributaries to Green Bay. Many knowledge gaps still exist with respect to the chronology of adult river migrations, including the physical characteristics of upstream habitats selected for reproduction and the extent of larval production by these riverine ecotypes. Here, we use hydroacoustic imaging along with egg and larval surveys to evaluate this novel riverine spawning in 2017 and 2018. Highest abundance of adults was observed in the month of November as temperatures declined below 8 °C. Spawning areas consisted of cobble substrates, and site-specific fish densities were primarily correlated with river flows between 0.3 and 1.0 m/s, with specific values varying by tributary and year. Locations of egg deposition mirrored areas of high observed fish densities. Larval production was documented on each tributary using active trawl ichthyoplankton sampling, and larvae were observed outmigrating to open water environments. We estimated tributaries produced 452,000 larvae in 2017 and 721,000 larvae in 2018. To our knowledge, this represents the first documentation of successful lake whitefish larval production from Green Bay tributaries and suggests tributary spawning populations contribute to the greater abundance of lake whitefish observed in recent years.     

Phosphoglycerylethanolamine posttranslational modification of plant eukaryotic elongation factor 1alpha

Eukaryotic elongation factor 1alpha (eEF-1A) is a multifunctional protein. There are three known posttranslational modifications of eEF-1A that could potentially affect its function. Except for phosphorylation, the other posttranslational modifications have not been demonstrated in plants. Using matrix-assisted laser desorption/ionization-mass spectrometry and peptide mass mapping, we show that carrot (Daucus carota L.) eEF-1A contains a phosphoglycerylethanolamine (PGE) posttranslational modification. eEF-1A was the only protein labeled with [14C]ethanolamine in carrot cells and was the predominant ethanolamine-labeled protein in Arabidopsis seedlings and tobacco (Nicotiana tabacum L.) cell cultures. In vivo-labeling studies using [3H]glycerol, [32P]Pi, [14C]myristic acid, and [14C]linoleic acid indicated that the entire phospholipid phosphatidylethanolamine is covalently attached to the protein. The PGE lipid modification did not affect the partitioning of eEF-1A in Triton X-114 or its actin-binding activity in in vitro assays. Our in vitro data indicate that this newly characterized posttranslational modification alone does not affect the function of eEF-1A. Therefore, the PGE lipid modification may work in combination with other posttranslational modifications to affect the distribution and the function of eEF-1A within the cell.     

Green tissue‐specific production of a microbial endo‐cellulase in maize (Zea mays L.) endoplasmic‐reticulum and mitochondria converts cellulose into fermentable sugars

BACKGROUND: Commercial conversion of lignocellulosic biomass to fermentable sugars for biofuels and chemical byproducts uses relatively expensive bulk production of biologically active cellulase enzymes, which could alternatively be achieved by using solar energy for direct production of these enzymes within feedstock crop cellulosic biomass. RESULTS: The Acidothermus cellulolyticus endo‐cellulase E1 has been produced in transgenic maize plants. This heterologous enzyme was specifically targeted for accumulation into two sub‐cellular compartments, endoplasmic reticulum (ER) or mitochondria of plant leaves and stalks. Furthermore, successful use of this maize‐produced heterologous cellulase in converting cellulose into fermentable sugars for biofuels, has been confirmed. CONCLUSIONS: Green‐specific expression of cellulases in maize plants can avoid public controversies associated with production of transgene products in maize seeds and/or pollen. Sub‐cellular targeting of cellulases may result in better expression of transgene products because these compartments, specially ER, normally contain molecular chaperones that enhance protein folding and there the biological activity. Also, using solar energy to produce cellulases within crop cellulosic biomass can replace the costly process of cellulase production in microbial bioreactors, and therefore, save costs. Copyright © 2008 Society of Chemical Industry     

Correction of a statistical error: Comment.

Comments that there was a statistical error in C. Burt's (see record 1973-10531-001) article that examined the IQs of monozygotic twins reared apart and in the comment by A. R. Jensen (1972). The error concerned the use of coefficients of correlation, determination, and nondetermination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rich socio-cognitive agents for immersive training environments: case of NonKin Village

Demand is on the rise for scientifically based human-behavior models that can be quickly customized and inserted into immersive training environments to recreate a given society or culture. At the same time, there are no readily available science model-driven environments for this purpose (see survey in Sect. 2). In researching how to overcome this obstacle, we have created rich (complex) socio-cognitive agents that include a large number of social science models (cognitive, sociologic, economic, political, etc) needed to enhance the realism of immersive, artificial agent societies. We describe current efforts to apply model-driven development concepts and how to permit other models to be plugged in should a developer prefer them instead. The current, default library of behavioral models is a metamodel, or authoring language, capable of generating immersive social worlds. Section 3 explores the specific metamodels currently in this library (cognitive, socio-political, economic, conversational, etc.) and Sect. 4 illustrates them with an implementation that results in a virtual Afghan village as a platform-independent model. This is instantiated into a server that then works across a bridge to control the agents in an immersive, platform-specific 3D gameworld (client). Section 4 also provides examples of interacting in the resulting gameworld and some of the training a player receives. We end with lessons learned and next steps for improving both the process and the gameworld. The seeming paradox of this research is that as agent complexity increases, the easier it becomes for the agents to explain their world, their dilemmas, and their social networks to a player or trainee.     

A coupled analysis method for structures with independently modelled finite element subdomains

A new method for analysing plate and shell structures with two or more independently modelled finite element subdomains is presented, assessed, and demonstrated. This method provides a means of coupling local and global finite element models whose nodes do not coincide along their common interface. In general, the method provides a means of coupling structural components (e.g., wing and fuselage) which may have been modelled by different analysts. In both cases, the need for transition modelling, which is often tedious and complicated, is eliminated. The coupling is accomplished through an interface for which three formulations are considered and presented. These formulations are: collocation, discrete least-squares, and hybrid variational. Several benchmark problems are analysed and it is shown that the hybrid variational formulation provides the most accurate solutions.     

Effects of glucose deprivation, chemical hypoxia, and simulated ischemia on Na+ homeostasis in rat spinal cord astrocytes

A steep inwardly directed Na+ gradient is essential for glial functions such as glutamate reuptake and regulation of intracellular ion concentrations. We investigated the effects of glucose deprivation, chemical hypoxia, and simulated ischemia on intracellular Na+ concentration ([Na+]i) in cultured spinal cord astrocytes using fluorescence ratio imaging with sodium-binding benzofuran isophthalate (SBFI) AM. Glucose removal or chemical hypoxia (induced by 10 mM NaN3) for 60 min increased [Na+]i from a baseline of 8.3 to 11 mM. Combined glycolytic and respiratory blockage by NaN3 and 0 glucose saline caused [Na+]i to increase by 20 mM, similar to the [Na+]i increases elicited by blocking the Na+/K+-ATPase with ouabain. Recovery from large [Na+]i increases (>15 mM) induced by the glutamatergic agonist kainate was attenuated during glucose deprivation or NaN3 application and was blocked in NaN3 and 0 glucose. To mimic in vivo ischemia, we exposed astrocytes to NaN3 and 0 glucose saline containing L-lactate and glutamate with increased [K+] and decreased [Na+], [Ca2+], and pH. This induced an [Na+]i decrease followed by an [Na+]i rise and a further [Na+]i increase after reperfusion with standard saline. Similar multiphasic [Na+]i changes were observed after NaN3 and 0 glucose saline with only reduced [Na+]e. Our results suggest that the ability to maintain a low [Na+]i enables spinal cord astrocytes to continue uptake of K+ and/or glutamate at the onset of energy failure. With prolonged energy failure, however, astrocytic [Na+]i rises; with loss of their steep transmembrane Na+ gradient, astrocytes may aggravate metabolic insults by carrier reversal and release of acid, K+, and/or glutamate into the extracellular space.     

Use of an ideal scaled model for scaling evaluation

In this paper a method is described for using RELAP5 models to corroborate the scaling methodology that has been used for design of the Purdue University multidimensional Test Apparatus. This facility was built for the U.S. NRC to obtain data on the performance of the passive safety systems of the General Electric Company simplified boiling water reactor. Similarity between the prototype system and the scaled test facility is investigated for a main steam line break accident.