Quantifying Planarian Behavior As An Introduction To Object Tracking And Signal Processing

Answers to mechanistic questions about biological phenomena require fluency in a variety of molecular biology techniques and physical concepts. Here, we present an interdisciplinary approach to introducing undergraduate students to an important problem in the areas of animal behavior and neuroscience—the neuronal control of animal behavior. In this lab module, students explore planarian behavior by quantitative image and data analysis with freely available software and low-cost resources. Planarians are ∼1–2-cm-long aquatic free-living flatworms famous for their regeneration abilities. They are inexpensive and easy to maintain, handle, and perturb, and their fairly large size allows for image acquisition with a webcam, which makes this lab module accessible and scalable. Our lab module integrates basic physical concepts such as center of mass, velocity and speed, periodic signals, and time series analysis in the context of a biological system. The module is designed to attract students with diverse disciplinary backgrounds. It challenges the students to form hypotheses about behavior and equips them with a basic but broadly applicable toolkit to achieve this quantitatively. We give a detailed description of the necessary resources and show how to implement the module. We also provide suggestions for advanced exercises and possible extensions. Finally, we provide student feedback from a pilot implementation

Induction of Tachykinin Production in Airway Epithelia in Response to Viral Infection

The tachykinins are implicated in neurogenic inflammation and the neuropeptide substance P in particular has been shown to be a proinflammatory mediator. A role for the tachykinins in host response to lung challenge has been previously demonstrated but has been focused predominantly on the release of the tachykinins from nerves innervating the lung. We have previously demonstrated the most dramatic phenotype described for the substance P encoding gene preprotachykinin-A (PPT-A) to date in controlling the host immune response to the murine gammaherpesvirus 68, in the lung.In this study we have utilised transgenic mice engineered to co-ordinately express the beta-galactosidase marker gene along with PPT-A to facilitate the tracking of PPT-A expression. Using a combination of these mice and conventional immunohistology we now demonstrate that PPT-A gene expression and substance P peptide are induced in cells of the respiratory tract including tracheal, bronchiolar and alveolar epithelial cells and macrophages after viral infection. This induction was observed 24h post infection, prior to observable inflammation and the expression of pro-inflammatory chemokines in this model. Induced expression of the PPT-A gene and peptide persisted in the lower respiratory tract through day 7 post infection.Non-neuronal PPT-A expression early after infection may have important clinical implications for the progression or management of lung disease or infection aside from the well characterised later involvement of the tachykinins during the inflammatory response

Angiotensin-converting enzyme gene insertion/deletion polymorphism is associated with risk of oral precancerous lesion in betel quid chewers

To investigate whether angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism is related to the risk of oral precancerous lesions (OPL) in Taiwanese subjects who chew betel quid, a total of 61 betel quid chewers having OPL were compared with 61 asymptomatic betel quid chewers matched for betel quid chewing duration and dosage. The frequency of homozygote for ACE D variant is significantly higher in the case subjects than that of the controls (44.3 vs 24.6%; P=0.0108). The adjusted odds ratio of the D homozygous for the risk of OPL is 8.10 (95% confidence interval (CI)=2.04–32.19, P=0.003). In the allelic base analysis, the D allele is also significantly associated with higher risk of OPL. When grouping the study subjects by smoking status, the association between ACE I/D polymorphism and risk of OPL was only observed in nonsmokers. Our results support the theory that genetic factors may contribute to the susceptibility of OPL and suggest that smoking and genetic factors may be differently involved in the development of OPL

Are Chicken Embryos Endotherms Or Ectotherms? A Laboratory Exercise Integrating Concepts In Thermoregulation And Metabolism

This investigative laboratory exercise uses the different relations between ambient temperature and metabolic rate in endotherms and ectotherms as a core concept to answer the following question: What thermoregulatory mode is employed by chicken embryos? Emphasis is placed on the physiological concepts that can be taught with this exercise, including methods for measuring rates of oxygen consumption, the relation between oxygen consumption and metabolic rate, the influence of temperature on metabolic rate, and the differences between endotherms and ectotherms both in the overall magnitude of metabolic rate and in the shape of the relation between metabolic rate and ambient temperature. Included in this article are respirometer designs suitable for teachers working with a wide variety of budgets and available equipment, specific laboratory protocols for collecting data, sample data, thought questions with sample answers, and suggestions for classroom implementation as a 1-, 2- or 3-wk laboratory exercise that can be taught at a variety of undergraduate levels

Rhythms of Drosophila period gene expression in culture

The Drosophila clock genes period (per) and timeless (tim) have been studied behaviorally and biochemically, but to date there has been no viable culture system for studying the cell biology of the Drosophila clock. We have cultured pupal ring glands attached to the central nervous system and observed rhythms of period gene expression in the prothoracic gland for 4–7 days. A daily rhythm of Per protein can be entrained by light in culture, even when neural activity is blocked by tetrodotoxin. In cultures maintained for a week in constant darkness, a per-luciferase reporter gene revealed circadian rhythms of bioluminescence. As the first circadian culture system from Drosophila, the prothoracic gland provides unique advantages for investigating the interactions between clock genes and cellular physiology