Mitra Mautusi, Broom Sara Michelle, Pinto Kysis, Wellons Sovi-Mya Doan, Roberts Ariel Dominique
Biology Department, University of West Georgia, Carrollton, GA, USA.
The Heritage School, Newnan, GA, USA.
PeerJ. 2020 Aug 25;8:e9817. doi: 10.7717/peerj.9817. eCollection 2020.
Photosynthesis and cellular respiration play major roles in energy metabolism and are important Life Science topics for K16 Biology students. Algae beads are used for photosynthesis and cellular respiration labs. Currently there are a few companies that sell biology educational kits for making algae beads using non-motile green micro-algae to introduce students to photosynthesis. These kits are expensive and, do not come with detailed guidelines for trouble shooting and customizations for different grade levels. is a motile green micro-alga and is an excellent model system for photosynthesis studies. In this article, we are presenting the work conducted in the student-driven, American Society of Plant Biologists-funded, Plant-BLOOME educational outreach project. This project is a supervised collaborative effort of three undergraduates and one high school student. We have generated a protocol which can be used to make beads. We have used these beads to design two simple and inexpensive plant biology hands-on activities. These laboratory activities have been customized to teach the interplay of photosynthesis and cellular respiration to K4-K16 Biology students.
beads were used for two different laboratory activities that involved monitoring pH changes over time using a pH indicator. Our first activity centers on making and, using light-powered algae bead bracelets to monitor dramatic color/pH changes over time when exposed to darkness or light. Our second activity employs strain-specific algae beads with approximately equal cell numbers to conduct comparative photosynthesis and cellular respiration studies in two strains namely, wild type, 4A+ and, a high light-sensitive, photosynthetic mutant, /.
We optimized our experimental protocol using algae beads in a 5.5 mL screw capped glass vials before performing the same experiment in algae bead bracelets. We found that the algal cell density/bead, water type used in the experiment and, the duration of dark exposure of algal beads can affect successful implementation of the lab activities. Light-powered algae bead bracelets showed dramatic color/pH changes within 3 h upon exposure to light or darkness. These bracelets could be switched back and forth between darkness and light multiple times within 48-72 h to display color/pH changes, provided prior dark exposure time did not exceed 9 h. Our comparative studies of photosynthesis and cellular respiration in and in 4A+ showed that relative respiration rate and photosynthetic rate is higher and lower in respectively, compared to that in 4A+. Additionally, failed to display the expected photosynthesis-induced pH/color changes in the light after prolonged exposure to darkness which indicated that prolonged dark exposure of , hindered photosynthesis.
光合作用和细胞呼吸在能量代谢中起主要作用，是K16生物学学生重要的生命科学主题。藻珠用于光合作用和细胞呼吸实验。目前有几家公司出售用于制作藻珠的生物学教育套件，这些套件使用非运动型绿色微藻来向学生介绍光合作用。这些套件价格昂贵，且没有附带针对不同年级水平的故障排除和定制的详细指南。衣藻是一种运动型绿色微藻，是光合作用研究的优秀模型系统。在本文中，我们展示了在学生主导、美国植物生物学家协会资助的植物BLOOME教育推广项目中开展的工作。该项目是三名本科生和一名高中生的监督协作成果。我们制定了一个可用于制作衣藻珠的方案。我们使用这些珠子设计了两个简单且成本低廉的植物生物学实践活动。这些实验室活动经过定制，用于向K4 - K16生物学学生讲授光合作用和细胞呼吸的相互作用。
衣藻珠用于两项不同的实验室活动，这些活动涉及使用pH指示剂监测随时间的pH变化。我们的第一个活动围绕制作并使用光驱动藻珠手链，以监测其在暴露于黑暗或光照时随时间的显著颜色/pH变化。我们的第二个活动使用细胞数量大致相等的特定菌株藻珠，在两种衣藻菌株，即野生型、4A +以及一种高光敏光合突变体中进行比较光合作用和细胞呼吸研究。
在藻珠手链中进行相同实验之前，我们在5.5毫升带螺旋盖的玻璃小瓶中使用藻珠优化了我们的实验方案。我们发现藻细胞密度/珠、实验中使用的水的类型以及藻珠黑暗暴露的持续时间会影响实验室活动的成功实施。光驱动藻珠手链在暴露于光照或黑暗后3小时内显示出显著的颜色/pH变化。如果之前的黑暗暴露时间不超过9小时，这些手链可以在48 - 72小时内多次在黑暗和光照之间切换以显示颜色/pH变化。我们对衣藻和4A +中的光合作用和细胞呼吸的比较研究表明，并与4A +相比，衣藻的相对呼吸速率较高而光合速率较低。此外，在长时间暴露于黑暗后，衣藻在光照下未能显示出预期的光合作用诱导的pH/颜色变化，这表明衣藻长时间暴露于黑暗会阻碍光合作用。
