Effect of \u3ci\u3eLactobacillus acidophilus\u3c/i\u3e Strain N P51 on\u3ci\u3e Escherichia coli \u3c/i\u3e0157:H7 Fecal Shedding and Finishing Performance in Beef Feedlot Cattle

A 2-year study was conducted during the summer months (May to September) to test the effectiveness of feeding Lactobacillus acidophilus strain NP51 on the proportion of cattle shedding Escherichia coli 0157:H7 in the feces and evaluate the effect of the treatment on finishing performance. Steers (n = 448) were assigned randomly to pens, and pens of cattle were assigned randomly to NP5 1 supplementation or no supplementation (control). NP5 1 products were mixed with water and applied as the feed was mixed daily in treatment-designated trucks at the rate of l09 CFU per steer. Fecal samples were collected (n = 3,360) from the rectum from each animal every 3 weeks, and E. coli 0157:H7 was isolated by standard procedures, using selective enrichment, immunomagnetic separation, and PCR confirmation. The outcome variable was the recovery of E. coli 0157:H7 from feces, and was modeled using logistic regression accounting for year, repeated measures of pens of cattle, and block. No significant differences were detected for gain, intakes, or feed efficiency of control or NP51-fed steers. The probability for cattle to shed E. coli 0157:H7 varied significantly between 2002 and 2003 (P = 0.004). In 2002 and 2003, the probability for NP5 1-treated steers to shed E. coli 0157:H7 over the test periods was 13 and 21 %, respectively, compared with 21 and 28% among controls. Over the 2 years, NP51-treated steers were 35% less likely to shed E. coli 0157: H7 than were steers in untreated pens (odds ratio = 0.58, P = 0.008). This study is consistent with previous reports that feeding NP51 is effective in reducing E. coli 0157:H7 fecal shedding in feedlot cattle

Evaluation of the Value of Fiber in Distillers Grains Plus Solubles on Performance of Finishing Cattle

A finishing study was conducted to determine the value of the fiber in distillers grains plus solubles on cattle performance. Five treatments were evaluated: a corn control diet, 20 or 40% modified distillers grains plus solubles, plus two diets containing corn germ meal and corn bran balanced to equal the fiber content of the two modified distillers grains plus solubles diets. Th ere was a significant improvement in ADG and F:G for cattle fed modified distillers grains plus solubles compared to control. Cattle fed the corn germ meal and bran diets had increased DMI, slightly lower ADG, and poorer F:G compared to the control. Th e isolated fiber component had 83– 90% the feeding value of corn, while modified distillers grains plus solubles had 107– 108%. Other components in distillers besides fiber must improve the value of distillers compared to corn

A Src-Tks5 Pathway Is Required for Neural Crest Cell Migration during Embryonic Development

In the adult organism, cell migration is required for physiological processes such as angiogenesis and immune surveillance, as well as pathological events such as tumor metastasis. The adaptor protein and Src substrate Tks5 is necessary for cancer cell migration through extracellular matrix in vitro and tumorigenicity in vivo. However, a role for Tks5 during embryonic development, where cell migration is essential, has not been examined. We used morpholinos to reduce Tks5 expression in zebrafish embryos, and observed developmental defects, most prominently in neural crest-derived tissues such as craniofacial structures and pigmentation. The Tks5 morphant phenotype was rescued by expression of mammalian Tks5, but not by a variant of Tks5 in which the Src phosphorylation sites have been mutated. We further evaluated the role of Tks5 in neural crest cells and neural crest-derived tissues and found that loss of Tks5 impaired their ventral migration. Inhibition of Src family kinases also led to abnormal ventral patterning of neural crest cells and their derivatives. We confirmed that these effects were likely to be cell autonomous by shRNA-mediated knockdown of Tks5 in a murine neural crest stem cell line. Tks5 was required for neural crest cell migration in vitro, and both Src and Tks5 were required for the formation of actin-rich structures with similarity to podosomes. Additionally, we observed that neural crest cells formed Src-Tks5-dependent cell protrusions in 3-D culture conditions and in vivo. These results reveal an important and novel role for the Src-Tks5 pathway in neural crest cell migration during embryonic development. Furthermore, our data suggests that this pathway regulates neural crest cell migration through the generation of actin-rich pro-migratory structures, implying that similar mechanisms are used to control cell migration during embryogenesis and cancer metastasis

WHY INVOLVE STUDENTS IN RESEARCH?

This article addresses the benefits of undergraduate research to students, to faculty, and to universities. Research experiences are credited with increasing motivation for learning, helping undergraduate students decide on a career path, forming mentoring relationships between students and faculty, and improving student performance in writing, speaking, and working in teams. For many students, research experiences are their most memorable experiences as undergraduates. From the perspective of universities, students bring enthusiasm to research teams and often ask insightful questions-sometimes quite by accident-that can change the ways faculty approach research inquiries. Student researchers contribute to the world of knowledge. Research universities have distinct advantages in offering undergraduate research opportunities. For example, research and education strongly complement each other. Undergraduate students benefit from the libraries, laboratories, and computers that support faculty research and graduate education. Our experience at Penn State indicates that offering research opportunities to undergraduate students is an educational activity that doesn\u27t cost large sums of money, although it does require substantial commitments of faculty time. Offering undergraduate research is a valuable recruiting tool, especially for academically gifted students. Several examples of undergraduate research at Penn State are included, for students in a variety of academic disciplines

Export Performance and State Industrial Growth

This research examines whether state industrial growth over the past decade has occurred independently of changes in manufacturing exports and whether export employment growth responds to the same economic and locational forces as employment growth in domestic production. The empirical results indicate that employment and value added growth are not independent of export sales growth; however, a shift toward export markets is not strongly associated with higher manufacturing growth rates. Traditional factors account for a far greater proportion of the variation in domestic than export employment growth. The results suggest the need for additional research on the sources of state comparative advantage in export markets.CES,economic,research,micro,data,microdata,chief,economist