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Dragline silk has been proposed to contain two main protein constituents, MaSp1 and MaSp2. However, the mechanical properties of synthetic spider silks spun from recombinant MaSp1 and MaSp2 proteins have yet to approach natural fibers, implying the natural spinning dope is missing critical factors. Here we report the discovery of novel molecular constituents within the spinning dope that are extruded into dragline silk. Protein studies of the liquid spinning dope from the major ampullate gland, coupled with the analysis of dragline silk fibers using mass spectrometry, demonstrate the presence of a new family of low-molecular-weight cysteine-rich proteins (CRPs) that colocalize with the MA fibroins. Expression of the CRP family members is linked to dragline silk production, specifically MaSp1 and MaSp2 mRNA synthesis. Biochemical data support that CRP molecules are secreted into the spinning dope and assembled into macromolecular complexes via disulfide bond linkages. Sequence analysis supports that CRP molecules share similarities to members that belong to the cystine slipknot superfamily, suggesting that these factors may have evolved to increase fiber toughness by serving as molecular hubs that dissipate large amounts of energy under stress. Collectively, our findings provide molecular details about the components of dragline silk, providing new insight that will advance materials development of synthetic spider silk for industrial applications.

The outstanding material properties of spider dragline silk fibers have been attributed to two spidroins, major ampullate spidroins 1 and 2 (MaSp1 and MaSp2). Although dragline silk fibers have been treated with different chemical solvents to elucidate the relationship between protein structure and fiber mechanics, there has not been a comprehensive proteomic analysis of the major ampullate (MA) gland, its spinning dope, and dragline silk using a wide range of chaotropic agents, inorganic salts, and fluorinated alcohols to elucidate their complete molecular constituents. In these studies, we perform in-solution tryptic digestions of solubilized MA glands, spinning dope and dragline silk fibers using five different solvents, followed by nano liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis with an Orbitrap Fusion™ Tribrid™. To improve protein identification, we employed three different tryptic peptide fragmentation modes, which included collision-induced dissociation (CID), electron transfer dissociation (ETD), and high energy collision dissociation (HCD) to discover proteins involved in the silk assembly pathway and silk fiber. In addition to MaSp1 and MaSp2, we confirmed the presence of a third spidroin, aciniform spidroin 1 (AcSp1), widely recognized as the major constituent of wrapping silk, as a product of dragline silk. Our findings also reveal that MA glands, spinning dope, and dragline silk contain at least seven common proteins: three members of the Cysteine-Rich Protein Family (CRP1, CRP2 and CRP4), cysteine-rich secretory protein 3 (CRISP3), fasciclin and two uncharacterized proteins. In summary, this study provides a proteomic blueprint to construct synthetic silk fibers that most closely mimic natural fibers.

Early preventive interventions for depressive disorders in racial/ethnic minorities may help to reduce lifetime depression outcome disparities by improving developmental trajectories and social outcomes. We describe the development process, intervention and evaluation plan for a culturally adapted, low-cost, primary care/Internet-based depression-prevention intervention (CURB, Chicago Urban Resiliency Building). CURB is culturally adapted for socio-economically disadvantaged African-American and Latino adolescents according to the PEN-3 model of health promotion programs (Airhihenbuwa in Health and culture: beyond the Western paradigm, Sage Publishers, Thousand Oaks, 1995). Based on the idea that health behavior is rooted in culture, the PEN-3 model contains three interdependent dimensions that influence health beliefs and behaviors. Within each dimension are factors (using the acronym PEN) that must be considered about the target culture. Application of the PEN-3 model occurred in 3 phases. In each phase, a dimension of the model was explored and subsequent changes were made to the intervention so as to be more culturally suitable. In the CURB clinical trial, adolescents ages 13–17 will be recruited from wait-lists for mental health services at community health care provider organizations and screened for risk of future depressive disorder in the primary care sites. Adolescents screening positive for persistent depressed mood will be randomly assigned to either the CURB intervention group or the wait-list control group. The study aims are to determine if participants in the CURB intervention group will have lower levels of depressive symptoms and/or a lower cumulative incidence of depressive episodes.

Our group developed a novel description of packing in protein structure that provides an amino acid code to protein design. To test the knob-socket model's application in protein design, a protein fold with five α-helices arranged in a five-pointed star topology has been designed: the helical star fold. For α-helical protein design, the knob-socket model is described as a four residue tetrahedral motif, where a single amino acid knob from one α-helix packs into a three amino acid socket within another α-helix. The three residue sockets can be classified into three categories: (1) free, unpacked favoring helical structures, (2) filled, packed favoring inter-helical interactions, and (3) disfavoring α-helical structure. Each type of socket has previously been characterized and show preferences for certain amino acid compositions. A practical application of the amino acid preferences for each socket type is a rational method for design of α-helical structure. To start the helical star fold, a 37 residue α-helix was constructed with only free sockets that served as the basis sequence to each leg of the star. Using known crossing angles between helices, specific packing patterns were designed between helices by changing the composition of free sockets into filled sockets and corresponding knobs. In the helical star fold, each α-helical leg crosses once with two other α-helices, meaning each helical leg has two patches of filled sockets. Short connecting loops between helices were designed to promote the packing between non-consecutive helical legs and therefore favor the star packing. The theoretical amino acid sequence was used for gene synthesis and cloning for over-expression in E. coli. The novel star protein was purified and analyzed for α-helical content using circular dichroism. The results provide further support of the knob-socket model and code for protein packing.

Longitudinal cracking and longitudinal joint separations are commonly observed distresses in concrete pavements. The Texas Department of Transportation instituted a research project to determine the causes and to recommend repair methods. Repair methods that are generally recommended to repair cracks and joints are (1) cross stitching; (2) slot stitching; and (3) stapling. Finite element modeling was performed to determine the stress distribution in the concrete for each method when a truck tire load was placed on one side of the joint. Assuming no interlock between joint faces, the slot stitching model produced the lowest stress and cross stitching produced the highest stress, when the load was placed on the upper end of the diagonal bar. Cross stitching is recommended for repairing narrow cracks and slot stitching is recommended for wider cracks and joints.

Recent reports indicate that violence toward others is a major public health problem in the black community; however, there are very few empirical studies that delineate the severity of the problem. In an effort to add to the meager data on violence in the black community, the authors compiled the results of a victimization screening form obtained from a black outpatient psychiatric population. Recommendations are made that black psychiatric populations be screened for histories of victimization, as victimization is common in this population group and will have a significant impact on treatment.