An Approach to Improving Student Success in Science, Technology, Engineering, and Mathematics (STEM) Career Pathways.

In this article, we report on an 11-year study that explores approaches to improve student success in college by a five-week summer program in Mathematics and Language Arts for entering freshmen. To recruit students into the program, we invited students accepted at the university and listed as underrepresented and economically disadvantaged (Pell-eligible) by the Office of Institutional Research at California State University, Northridge. The program consisted of all-day Math and English enhancement in mixed ability groups.

Terminal alpha-d-mannosides are critical during sea urchin gastrulation.

The sea urchin embryo is a United States National Institutes of Health (NIH) designated model system to study mechanisms that may be involved in human health and disease. In order to examine the importance of high-mannose glycans and polysaccharides in gastrulation, Lytechinus pictus embryos were incubated with Jack bean α-mannosidase (EC 3.2.

Involvement of l(-)-rhamnose in sea urchin gastrulation. Part II: α-l-Rhamnosidase.

The sea urchin embryo is recognized as a model system to reveal developmental mechanisms involved in human health and disease. In Part I of this series, six carbohydrates were tested for their effects on gastrulation in embryos of the sea urchin Lytechinus pictus. Only l-rhamnose caused dramatic increases in the numbers of unattached archenterons and exogastrulated archenterons in living, swimming embryos.

Microbead analysis of cell binding to immobilized lectin. Part II: Quantitative kinetic profile assay for possible identification of anti-infectivity and anti-cancer reagents.

There has been a re-emergence of the use of lectins in a variety of therapeutic venues. In addition lectins are often responsible for the binding of pathogens to cells and for cancer cell clumping that increases their escape from body defenses. It is important to define precisely the activity of inhibitors of lectin-binding that may be used in anti-infection and anti-cancer therapeutics.

Involvement of L(-)-rhamnose in sea urchin gastrulation: a live embryo assay.

The sea urchin embryo is a National Institutes of Health model system that has provided major developments, and is important in human health and disease. To obtain initial insights to identify glycans that mediate cellular interactions, Lytechinus pictus sea urchin embryos were incubated at 24 or 30 h post-fertilization with 0.0009-0.

A role for polyglucans in a model sea urchin embryo cellular interaction.

The enzymatic activities of commercially prepared glycosidases were verified by direct chemical assays using defined substrates and fixed and live sea urchin (Lytechinus pictus) embryos to determine if a model cellular interaction of interest to developmental biologists for over a century (interaction of archenteron tip and roof of the blastocoel) was mediated by glycans. Glycosidases (active and denatured) were incubated with microdissected archenterons and blastocoel roofs in a direct assay to learn if their enzymatic activities could prevent the normal adhesive interaction. Of the five glycosidases tested only β-amylase (an exoglycosidase) immediately inhibited the interaction at relatively low unit activity.

Use of specific glycosidases to probe cellular interactions in the sea urchin embryo.

We present an unusual and novel model for initial investigations of a putative role for specifically conformed glycans in cellular interactions. We have used alpha- and ss-amylase and alpha- and ss-glucosidase in dose-response experiments evaluating their effects on archenteron organization using the NIH designated sea urchin embryo model. In quantitative dose-response experiments, we show that defined activity levels of alpha-glucosidase and ss-amylase inhibited archenteron organization in living Lytechinus pictus gastrula embryos, whereas all concentrations of ss-glucosidase and alpha-amylase were without substantial effects on development.

A glycobiology review: carbohydrates, lectins and implications in cancer therapeutics.

This review is intended for general readers who would like a basic foundation in carbohydrate structure and function, lectin biology, and the implications of glycobiology in human health and disease, particularly in cancer therapeutics. These topics are among the hundreds included in the field of glycobiology and are treated here because they form the cornerstone of glycobiology or the focus of many advances in this rapidly expanding field.

Exogenous hyalin and sea urchin gastrulation. Part IV: a direct adhesion assay - progress in identifying hyalin's active sites.

In Strongylocentrotus purpuratus the hyalins are a set of three to four rather large glycoproteins (hereafter referred to as 'hyalin'), which are the major constituents of the hyaline layer, the developing sea urchin embryo's extracellular matrix. Recent research from our laboratories has shown that hyalin is a cell adhesion molecule involved in sea urchin embryo-specific cellular interactions. Other laboratories have shown it to consist of 2-3% carbohydrate and a cloned, sequenced fragment demonstrated repeat domains (HYR) and non-repeat regions.

Exogenous hyalin and sea urchin gastrulation. Part III: biological activity of hyalin isolated from Lytechinus pictus embryos.

Hyalin is a large glycoprotein, consisting of the hyalin repeat domain and non-repeated regions, and is the major component of the hyaline layer in the early sea urchin embryo of Strongylocentrotus purpuratus. The hyalin repeat domain has been identified in proteins from organisms as diverse as bacteria, sea urchins, worms, flies, mice and humans. While the specific function of hyalin and the hyalin repeat domain is incompletely understood, many studies suggest that it has a functional role in adhesive interactions.

Hyalin is a cell adhesion molecule involved in mediating archenteron-blastocoel roof attachment.

The US National Institutes of Health has designated the sea urchin embryo as a model organism because around 25 discoveries in this system have led to insights into the physiology of higher organisms, including humans. Hyalin is a large glycoprotein in the hyaline layer of sea urchin embryos that functions to maintain general adhesive relationships in the developing embryo. It consists of the hyalin repeat domain that has been identified in organisms as diverse as bacteria, worms, flies, mice, sea urchins and humans.

Carbohydrate-based experimental therapeutics for cancer, HIV/AIDS and other diseases.

This review, primarily for general readers, briefly presents experimental approaches to therapeutics of cancer, HIV/AIDS and various other diseases based on advances in glycobiology and glycochemistry. Experimental cancer and HIV/AIDS vaccines are being developed in attempts to overcome weak immunological responses to carbohydrate-rich surface antigens using carriers, adjuvants and novel carbohydrate antigen constructs. Current carbohydrate-based vaccines are used for typhus, pneumonia, meningitis; vaccines for anthrax, malaria and leishmaniasis are under development.

Lectin binding and effects in culture on human cancer and non-cancer cell lines: examination of issues of interest in drug design strategies.

By using a non-cancer and a cancer cell line originally from the same tissue (colon), coupled with testing lectins for cell binding and for their effects on these cell lines in culture, this study describes a simple multi-parameter approach that has revealed some interesting results that could be useful in drug development strategies. Two human cell lines, CCL-220/Colo320DM (human colon cancer cells, tumorigenic in nude mice) and CRL-1459/CCD-18Co (non-malignant human colon cells) were tested for their ability to bind to agarose microbeads derivatized with two lectins, peanut agglutinin (Arachis hypogaea agglutinin, PNA) and Dolichos biflorus agglutinin (DBA), and the effects of these lectins were assessed in culture using the MTT assay. Both cell lines bound to DBA-derivatized microbeads, and binding was inhibited by N-acetyl-D-galactosamine, but not by L-fucose.

Cyclodextrin, a probe for studying adhesive interactions.

In this short communication, we introduce alpha-cyclodextrin as a new probe to study mechanisms of adhesive interactions. We show that this cyclic polysaccharide, that consisting of six glucosyl residues linked by alpha-1,4 bonds, was the only sugar of 22 tested that dramatically blocked a specific cellular interaction in the sea urchin embryo (p<0.001 compared with non-sugar controls).

Microbead analysis of cell binding to immobilized lectin: an alternative to microarrays in the development of carbohydrate drugs and diagnostic tests.

Microarray technology is currently used in the development of carbohydrate drugs and diagnostic tests. Here we model an inexpensive alternative to microarrays using derivatized microbeads. In this model we examine the binding of mannose-rich yeast to microbeads derivatized with concanavalin A (Con A), a mannose-binding lectin, in the presence of 30 different sugars and 9 different pH conditions.

Cellular basis of cancer metastasis: A review of fundamentals and new advances.

This review provides an introduction to fundamentals and new advances in cancer metastasis for general readers. The first segment includes topics such as cell adhesion, cell migration, proteases, inflammation, coagulation and site selection in metastasis. Then follows a discussion of an interesting report by Kaplan et al.

Analysis of unconventional approaches for the rapid detection of surface lectin binding ligands on human cell lines.

For over a decade our laboratory has developed and used a novel histochemical assay using derivatized agarose beads to examine the surface properties of various cell types. Most recently, we have used this assay to examine lectin binding ligands on two human cell types, CCL-220, a colon cancer cell line, and CRL-1459, a non-cancer colon cell line. We found that CCL-220 cells bound specific lectins better than CRL-1459, and this information was used to test for possible differential toxicity of these lectins in culture, as a possible approach in the design of more specific anti-cancer drugs.