The ‘grand scheme of things’: biological invasions, their detection, impacts and management

Editorial of Management of Biological Invasions: International Journal of Applied Research on Biological Invasions, Volume 5, Issues 3

The Immediate Feedback Assessment Technique (IF-AT) in a Large Enrollment Introductory Organic Chemistry Course

Students are often discouraged by standard multiple choice tests because they do not provide the opportunity for part marks. In addition, research indicates that students do not learn from mistakes made during multiple choice tests, in part owing to the delay between completing the test and receiving feedback. An excellent alternative to using standard multiple choice tests with scantron answer sheets is the Immediate Feedback Assessment Technique (IF-AT) which utilizes an answer-until-correct format. The IF-AT provides students with immediate feedback and allows for the assignment of part marks. This assessment technique was used for the midterm test and final exam of a large enrollment (\u3e200) introductory organic chemistry course. The effect of the IF-AT on course grades and student learning, and student reaction to the IF-AT will be described

Breeding objectives for Angus and Charolais specialized sire lines for use in the emerging sector of South African beef production

Breeding indigenous cows to terminal sires may facilitate production of calves in the emerging sector that better meet commercial feedlot requirements. Thus, the objective of this research was to develop breeding objectives for Angus and Charolais terminal sires to be used in breeding Afrikaner, Bonsmara, and Nguni cows. An aggregated simulation model that is reliant on user inputs for the phenotypic characterization of the germplasm and economic characterization of the production environment was developed. Relative economic values were calculated by approximating partial derivatives of simulated profit with respect to economically relevant traits. Correlations among the breeding objectives calculated from simulations of Angus and Charolais bulls bred to Afrikaner, Bonsmara and Nguni cows were consistently > 0.9. Thus, an average index could be used for all six scenarios with little loss of selection efficiency. On average, relative emphasis given to breeding values for survival, direct weaning weight, postweaning daily gain, postweaning daily feed intake, dressing percent, and fat depth were 31.1, 31.0, 17.3, 1.4, 19.1, 0.2%, respectively. These breeding objectives may be viewed as an appropriate step in the evolution of multi-trait selection to facilitate poverty alleviation among cattle producers in the emerging sector through wealth creation resulting from their production of calves for industrial feeding. Keywords: Beef cattle, genetic evaluation, selection strategy, crossbreeding, cow-calf production system South African Journal of Animal Science Vol. 37 (1) 2007: pp. 1-1

Investigating neovascularization in rat decellularized intestine - an in vitro platform for studying angiogenesis

One of the main challenges currently faced by tissue engineers is the loss of tissues post implantation due to delayed neovascularization. Several strategies are under investigation to create vascularized tissue but none have yet overcome this problem. In this study we produced a decellularized natural vascular scaffold from rat intestine to use as an in vitro platform for neovascularization studies for tissue engineered constructs. Decellularization resulted in almost complete (97%) removal of nuclei and DNA, while collagen, glycosaminoglycans and laminin content was preserved. Decellularization did, however, result in the loss of elastin and fibronectin. Some proangiogenic factors were retained, as fragments of decellularized intestine were able to stimulate angiogenesis in the chick chorioallantoic membrane assay. We demonstrated that decellularization left perfusable vascular channels intact, and these could be repopulated with human dermal microvascular endothelial cells. Optimization of reendothelialisation of the vascular channels showed this was improved by continuous perfusion of the vasculature and further improved by infusion of human dermal fibroblasts into the intestinal lumen, from where they invaded into the decellularized tissue. Finally we explored the ability of the perfused cells to form new vessels. In the absence of exogenous angiogenic stimuli, Dll4, a marker of endothelial capillary-tip cell activation during sprouting angiogenesis was absent, indicating the reformed vasculature was largely quiescent. However, after addition of VEGFA, Dll4 positive endothelial cells could be detected, demonstrating this engineered vascular construct maintained its capacity for neovascularization. In summary we have demonstrated how a natural xenobiotic vasculature can be used as an in vitro model platform to study 3 neovascularization and provide information on factors that are critical for efficient reendothelialisation of decellularized tissue

Economic selection index development for Beefmaster cattle I: Terminal breeding objective

The objective of this study was to develop an economic selection index for Beefmaster cattle in a terminal production system where bulls are mated to mature cows with all resulting progeny harvested. National average prices from 2010 to 2014 were used to establish income and expenses for the system. Phenotypic and genetic parameter values among the selection criteria and goal traits were obtained from literature. Economic values were estimated by simulating 100,000 animals and approximating the partial derivatives of the profit function by perturbing traits one at a time, by 1 unit, while holding the other traits constant at their respective means. Relative economic values (REV) for the terminal objective traits HCW, marbling score (MS), ribeye area (REA), 12th–rib fat (FAT), and feed intake (FI) were 91.29, 17.01, 8.38, -7.07, and -29.66, respectively. Consequently, improving the efficiency of beef production is expected to impact profitability greater than improving carcass merit alone. The accuracy of the index lies between 0.338 (phenotypic selection) and 0.503 (breeding values known without error). The application of this index would aid Beefmaster breeders in their sire selection decisions, facilitating genetic improvement for a terminal breeding objective

Fabrication of biodegradable synthetic vascular networks and their use as a model of angiogenesis

One of the greatest challenges currently faced in tissue engineering is the incorporation of vascular networks within tissue-engineered constructs. The aim of this study was to develop a technique for producing a perfusable, three-dimensional cell friendly model of vascular structures that could be used to study the factors affecting angiogenesis and vascular biology in engineered systems in more detail. Initially, biodegradable synthetic pseudo-vascular networks were produced via the combination of robocasting and electrospinning techniques. The internal surfaces of the vascular channels were then recellularized with human dermal microvascular endothelial cells (HDMECs) with and without the presence of human dermal fibroblasts (HDFs) on the outer surface of the scaffold. After 7 days in culture, channels that had been reseeded with HDMECs alone, demonstrated irregular cell coverage. However when using a co-culture of HDMECs inside and HDFs outside the vascular channels, coverage was found to be continuous throughout the internal channel. Using this cell combination, collagen gels loaded with vascular endothelial growth factor were deposited onto the outer surface of the scaffold and cultured for a further 7 days after which endothelial cell (EC) outgrowth from within the channels into the collagen gel was observed showing the engineered vasculature maintains its capacity for angiogenesis. Furthermore the HDMECs appeared to have formed perfusable tubules within the gel. These results show promising steps towards the development of an in vitro platform upon which to study angiogenesis and vascular biology in a tissue-engineering context

Identification of genomic regions that contribute to wet carcass syndrome in sheep

Wet carcass syndrome (WCS), which is observed predominantly in sheep, affects carcass quality negatively. After slaughter the carcass appears to be ‘wet’ with a subcutaneous accumulation of watery fluid. Not all animals in a contemporary group are afflicted, and experimental attempts to induce WCS have been unsuccessful. The reported prevalence of WCS in Dorper and Dorper crosses gave rise to the hypothesis that it may have a genetic basis. Therefore, the primary objective of this investigation was to test this hypothesis using a high-density SNP assay to search loci that may predispose sheep to WCS. Muscle samples from 43 afflicted and 41 unafflicted sheep were collected from slaughterhouses in the province of Northern Cape, South Africa, and in southern Namibia. Tests against candidate genes proved uninformative, as did runs of homozygosity. Potential associations between WCS and an autosomal genetic marker were investigated further in a case-control genome-wide association study. Separate analyses for each sex were motivated because single nucleotide polymorphisms (SNPs) on the X chromosome suggested quantitative trait loci. These analyses revealed significant associations between SNP and WCS in males, but not in females. Three SNPs that reached genome-wide significance in males are in strong linkage disequilibrium with the Duchenne muscular dystrophy, 5-hydroxytryptamine receptor 2C, and Teneurin transmembrane protein 1 genes. These genes are identified as positional candidate genes, and the Duchenne muscular dystrophy, 5-hydroxytryptamine receptor 2C genes have biological effects that have been documented in other species, making them plausible functional candidate genes for WCS in sheep.Keywords: association analysis, Dorper, sheep carcass, single nucleotide polymorphisms, X chromosom

Learning Task Inventories (LTIs) in Introductory Organic Chemistry

University students who are capable of more accurate self-monitoring and self-assessment usually outperform less accurate students. Instructional support is an important tool that can be provided for learners to help them to understand that they should self-monitor and self-assess as well as how they should do this. To assist students in an introductory organic chemistry course in developing or improving self-monitoring and self-assessment skills, we offered scaffolding support through nine Learning Task Inventories (LTIs), completed weekly throughout one term. A class of 289 students were randomly assigned to one of 5 conditions (1 control = C1, and 4 experimental = E2-E5). Each group experienced a set of LTI conditions that differed with respect to feedback received and cognitive load. Specifically, participants in C1 received the LTIs. Condition E2 received LTIs and a metacognitive prompt. Conditions E3-E5 completed a learning quiz with different types of feedback: E3 received no feedback, E4 received brief feedback (i.e. The correct answer is A), and E5 received full feedback explaining specific answers. Participants also completed an introductory survey gathering important demographic information and an end-of-term survey assessing student reactions to the LTIs. Consistent with expectations, preliminary data support improved learning gains for reported test scores (F(2.86) = 4.48 value, p \u3c .02 ), such that students who received full feedback on their quizzes outperformed students who only completed the quiz. This presentation will present the results pertaining to student attitudes and the effects of treatment conditions on final exam grades

Tamoxifen, 17beta-oestradiol and the calmodulin antagonist J8 inhibit human melanoma cell invasion through fibronectin.

Invasion through stromal extracellular matrix (ECM) is part of the complex, multistep process of tumour cell invasion and metastasis. Our group has previously demonstrated that calcium and calmodulin are important in another step in the metastatic cascade - that of attachment of cells to ECM. Interestingly, the non-steroidal anti-oestrogen tamoxifen (which also has calmodulin antagonist activity), used in the treatment of breast cancer and now in metastatic cutaneous melanoma, can inhibit the attachment of normal and neoplastic cells to ECM. In this study, we investigated whether such drugs, known to inhibit cell attachment, could also subsequently reduce their invasion through a layer of human fibronectin. We examined the ability of the specific calmodulin antagonist J8, tamoxifen and its two major metabolites, N-desmethyltamoxifen (N-des) and 4-hydroxytamoxifen (4-OH), as well as the pure anti-oestrogen ICI 182,780 and 17beta-oestradiol to inhibit invasion of the human cutaneous melanoma cell line, A375-SM, uveal melanoma cells and uveal melanocytes. A375-SM cells and uveal melanoma cells showed a high level of invasion (15.2% and 33.7% respectively) compared with melanocytes (around 5%) under the experimental conditions used. Submicromolar concentrations of N-des, tamoxifen, J8 and 17beta-oestradiol significantly reduced the invasiveness of the A375-SM cell line. The uveal melanoma cells also showed similar inhibition, although at higher concentrations of these agents. 4-OH and ICI 182, 780 had little or no effect on invasion of A375-SM cells (these were not tested on uveal melanoma cells). All cells used in this study were found to be negative for type I nuclear oestrogen receptors, reinforcing the possibility that tamoxifen and 17beta-oestradiol can act via mechanisms unrelated to binding to classical oestrogen receptors to inhibit tumour cell invasion

Localization and Expression of Osteopontin in Mineralized and Nonmineralized Tissues of the Periodontium a

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72134/1/j.1749-6632.1995.tb44628.x.pd