One approach to the general problem of the structure and function of enzymes involves proteolytic hydrolysis with examination of the structure, composition, and catalytic activity of the hydrolysis products. Fragments retaining partial enzyme activity have been obtained from trypsin and pepsin by autolysis (2, 3) and from trypsinogen by peptic digestion (4). Over half of the amino acid residues...

Intelligence is thought of as an assembly of “factors,” either one (g), a few, or many. This tool-driven metaphor (factor analysis) has its limits because it does not describe how cognition translates into behavior. We propose a new view of intelligence that provides the missing link in terms of heuristics. Human intelligence, in our view, is modeled by an adaptive toolbox that contains buildin...

There have been no previous studies on the genetics of Azotobacter paspali, an aerobic bacterium which forms a highly specific diazotrophic association with Bahia grass (Paspalum notatum). We constructed A. paspali strains defective in the molybdenum nitrogenase so that alternative N(2)ases could be studied. The cosmid vector pTBE and genomic DNA fragments ( approximately 50 kb) of A. paspali A...

We report the time-resolved recombination of photodissociated IBr-(CO2)n (n = 5-10) clusters following excitation to the dissociative IBr-A' 2Pi12 state of the chromophore via a 180 fs, 795 nm laser pulse. Dissociation from the A' state of the bare anion results in I- and Br products. Upon solvation with CO2, the IBr- chromophore regains near-IR absorption only after recombination and vibration...

The gene encoding bacteriophage T7 RNA polymerase (T7gene1) was placed under the control of regulatory elements from the Escherichia coli lac operon to construct an inducible vaccinia virus expression system consisting entirely of prokaryotic transcriptional machinery. Regulated expression of T7 RNA polymerase was necessary to construct a stable recombinant vaccinia virus harboring a T7 promote...

The paper put forward transforming HTPB propellant into a luminescent signal agent in order to seek solution for its reuse after retirement. Considering comprehensively that propellants have similar content and pyrotechnic composition, red was designed the preparation process analysed. On basis of safe pulverization, strontium nitrate added as flame colorant they recombined with shellac binder ...

Porcine reproductive and respiratory syndrome (PRRS) is one of the most important swine diseases worldwide. In the present study, a new virulent strain of PRRS virus (PRRSV), GDsg, was isolated in Guangdong province, China, and caused high fever, high morbidity, and high mortality in sows and piglets. The genome of this new strain was 15,413 nucleotides (nt) long, and comparative analysis revea...

Cytoplasmic male sterility (CMS) results from incompatibility between nuclear and cytoplasmic genomes, and is characterized by the inability to produce viable pollen. The restoration of male fertility generally involves the introgression of nuclear genes, termed restorers of fertility (Rf). CMS has been widely used for hybrid seed production in many crops but not in wheat, partly owing to the c...

The process of allelic exclusion ensures that each B cell expresses a B-cell receptor encoded by only one of its Ig heavy (IgH) and light (IgL) chain alleles. Although its precise mechanism is unknown, recruitment of the nonfunctional IgH allele to centromeric heterochromatin correlates with the establishment of allelic exclusion. Similarly, recruitment in activated splenic B cells correlates w...