3,840 research outputs found
Highly Efficient Site-Specific Mutagenesis in Malaria Mosquitoes Using CRISPR.
Anopheles mosquitoes transmit at least 200 million annual malaria infections worldwide. Despite considerable genomic resources, mechanistic understanding of biological processes in Anopheles has been hampered by a lack of tools for reverse genetics. Here, we report successful application of the CRISPR/Cas9 system for highly efficient, site-specific mutagenesis in the diverse malaria vectors Anopheles albimanus, A. coluzzii, and A. funestus When guide RNAs (gRNAs) and Cas9 protein are injected at high concentration, germline mutations are common and usually biallelic, allowing for the rapid creation of stable mutant lines for reverse genetic analysis. Our protocol should enable researchers to dissect the molecular and cellular basis of anopheline traits critical to successful disease transmission, potentially exposing new targets for malaria control
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Genome-wide patterns of polymorphism in an inbred line of the African malaria mosquito Anopheles gambiae.
Anopheles gambiae is a major mosquito vector of malaria in Africa. Although increased use of insecticide-based vector control tools has decreased malaria transmission, elimination is likely to require novel genetic control strategies. It can be argued that the absence of an A. gambiae inbred line has slowed progress toward genetic vector control. In order to empower genetic studies and enable precise and reproducible experimentation, we set out to create an inbred line of this species. We found that amenability to inbreeding varied between populations of A. gambiae. After full-sib inbreeding for ten generations, we genotyped 112 individuals--56 saved prior to inbreeding and 56 collected after inbreeding--at a genome-wide panel of single nucleotide polymorphisms (SNPs). Although inbreeding dramatically reduced diversity across much of the genome, we discovered numerous, discrete genomic blocks that maintained high heterozygosity. For one large genomic region, we were able to definitively show that high diversity is due to the persistent polymorphism of a chromosomal inversion. Inbred lines in other eukaryotes often exhibit a qualitatively similar retention of polymorphism when typed at a small number of markers. Our whole-genome SNP data provide the first strong, empirical evidence supporting associative overdominance as the mechanism maintaining higher than expected diversity in inbred lines. Although creation of A. gambiae lines devoid of nearly all polymorphism may not be feasible, our results provide critical insights into how more fully isogenic lines can be created
Recruitment of Veterinarians for Rural Communities through Education: The Veterinary Training Program for Rural Kansas
Veterinarians are important members of rural communities and provide valuable services to both community members and the food production systems in these areas. The population of new veterinary graduates entering rural, mixed animal practice is decreasing and several studies have concluded that a shortage of veterinarians in this area is apparent. The Veterinary Training Program for Rural Kansas (VTPRK) was created to address the educational and financial needs of students entering practice in rural Kansas. The program provides a forgivable loan for a select group of students during veterinary school and specific courses to help prepare these students for success in rural practice
Germline Cas9 expression yields highly efficient genome engineering in a major worldwide disease vector, Aedes aegypti.
The development of CRISPR/Cas9 technologies has dramatically increased the accessibility and efficiency of genome editing in many organisms. In general, in vivo germline expression of Cas9 results in substantially higher activity than embryonic injection. However, no transgenic lines expressing Cas9 have been developed for the major mosquito disease vector Aedes aegypti Here, we describe the generation of multiple stable, transgenic Ae. aegypti strains expressing Cas9 in the germline, resulting in dramatic improvements in both the consistency and efficiency of genome modifications using CRISPR. Using these strains, we disrupted numerous genes important for normal morphological development, and even generated triple mutants from a single injection. We have also managed to increase the rates of homology-directed repair by more than an order of magnitude. Given the exceptional mutagenic efficiency and specificity of the Cas9 strains we engineered, they can be used for high-throughput reverse genetic screens to help functionally annotate the Ae. aegypti genome. Additionally, these strains represent a step toward the development of novel population control technologies targeting Ae. aegypti that rely on Cas9-based gene drives
Professional Services Offered in Rural, Mixed-Animal Veterinary Practices
Rural, mixed animal veterinary practices offer a variety of professional services to their clientele. Practitioners must decide which services to offer and how much time to dedicate to each offering. These decisions are influenced by the perceived need for each service in the area and the potential income that can be generated from the specific service
Backgrounding health associated with area of the truck where cattle were housed during transport
Cattle are commonly moved between geographic regions by using commercial transport
carriers, and the vast majority of cattle are transported at least one time during their lives. Both handling and travel associated with moving cattle between locations have been identified as potentially stressful events. The objective of this research was to identify potential associations between calf location within the transport carrier and subsequent calf wellness in the short term (40 to 60 days) following shipment. Health outcomes and average daily gain (ADG) were used to measure calf wellness during the backgrounding period. Although some research has described the overall effect of hauling cattle, we are aware of no recent literature describing the effects of location within the vehicle on subsequent animal wellness and performance
Backgrounding health associated with area of the truck where cattle were housed during transport
Cattle are commonly moved between geographic regions by using commercial transport carriers, and the vast majority of cattle are transported at least one time during their lives. Both handling and travel associated with moving cattle between locations have been identified as potentially stressful events. The objective of this research was to identify potential associations between calf location within the transport carrier and subsequent calf wellness in the short term (40 to 60 days) following shipment. Health outcomes and average daily gain (ADG) were used to measure calf wellness during the backgrounding period. Although some research has described the overall effect of hauling cattle, we are aware of no recent literature describing the effects of location within the vehicle on subsequent animal wellness and performance
Connecting Supply Chain Through Sustainability: Initiating a Multi-Disciplinary, Multi-Industry Approach Using the Case of Beef Cattle
Disciplinary perspectives of supply chains are influenced by the āsiloā nature of academia. For
example, educators typically train students about appropriate supply chain management starting
with the manufacturer of products used in their particular industry, as opposed to investigating the
entire supply chain from raw material producer to finished consumer product through disposal or
recycling. When educating sustainability, understanding the extent and interrelated nature
of the entire supply chain is essential. Without foundational knowledge and systems thinking,
students may not understand the impact of business decisions on sustainability, and motivation to
make sustainable choices may be lacking. This project aims to develop a Collaborative Grant Type
2 to infuse sustainability education into a variety of baccalaureate programs (e.g., animal sciences,
hospitality and textile programs) using the study of beef cattle. Beef cattle present complex issues
that involve a global view of the challenge to feed, clothe and fuel 9.6 billion people by the year 2050
while conserving finite resources
The impact of item-writing flaws and item complexity on examination item difficulty and discrimination value
Citation: Rush, B. R., Rankin, D. C., & White, B. J. (2016). The impact of item-writing flaws and item complexity on examination item difficulty and discrimination value. BMC Medical Education, 16(1). doi:10.1186/s12909-016-0773-3Background: Failure to adhere to standard item-writing guidelines may render examination questions easier or more difficult than intended. Item complexity describes the cognitive skill level required to obtain a correct answer. Higher cognitive examination items promote critical thinking and are recommended to prepare students for clinical training. This study evaluated faculty-authored examinations to determine the impact of item-writing flaws and item complexity on the difficulty and discrimination value of examination items used to assess third year veterinary students. Methods: The impact of item-writing flaws and item complexity (cognitive level I-V) on examination item difficulty and discrimination value was evaluated on 1925 examination items prepared by clinical faculty for third year veterinary students. Results: The mean (Ā± SE) percent correct (83.3 % Ā± 17.5) was consistent with target values in professional education, and the mean discrimination index (0.18 Ā± 0.17) was slightly lower than recommended (0.20). More than one item-writing flaw was identified in 37.3 % of questions. The most common item-writing flaws were awkward stem structure, implausible distractors, longest response is correct, and responses are series of true-false statements. Higher cognitive skills (complexity level III-IV) were required to correctly answer 38.4 % of examination items. As item complexity increased, item difficulty and discrimination values increased. The probability of writing discriminating, difficult examination items decreased when implausible distractors and all of the above were used, and increased if the distractors were comprised of a series of true/false statements. Items with four distractors were not more difficult or discriminating than items with three distractors. Conclusion: Preparation of examination questions targeting higher cognitive levels will increase the likelihood of constructing discriminating items. Use of implausible distractors to complete a five-option multiple choice question does not strengthen the discrimination value. Ā© 2016 The Author(s)
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