KON Unit-4 Lab

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Unit #4 Lab: Photosynthetic bacteria, Protist and Fungi Learning objectives: 1. Familiarize with different divisions of photosynthetic organisms by using the representative members of each one. 2. Compare and contrast major divisions of algae. 3. Observe representative organisms classified within the kingdom Fungi 4. Identify morphological structures characteristic for different phyla of Fungi 5. Compare and contrast different reproduction strategies for different phyla of Fungi PART A: PHOTOSYNTHETIC BACTERIA AND PROTISTS I NTRODUCTION Cyanobacteria and algae are photosynthetic organisms that, because of their physiological and ecological affinities, had been grouped in the distant past as divisions of the plant kingdom. However, newly acquired knowledge of the cell biology, genetics and biochemistry of the groups clumped as algae has led to an overhaul of their classification. Cyanobacteria ( blue-green algae) is part of the eubacteria . This decision is a reflection of the prokaryotic nature of the cellular organization, physiology, biochemistry, and reproductive means of these microorganisms. Most C yanobacteria are aquatic, a few species are terrestrial and some cyanobacteria are in symbiosis with invertebrate animals. It is important to note that algae and cyanobacteria are so similar from an ecophysiological standpoint that both groups are capable of entering in symbiotic relationships with fungi to form lichens . Algae is a common name which describes a very diverse group of eukaryotic organisms that have been placed within the Protista . Despite photosynthetic capacity and their multicellularity, algae differ from higher plants in their lack of well-organized tissues and in their reproductive mechanisms. Current classification of eukaryotic organisms and photosynthetic organisms amongst them with the respect to modern phylogenetic data is represented on Fig. 1. Currently, eukaryotes are divided into four supergroups: Excavata, SAR, Archaeplastida and Unikonta, with algae distributed in all of them except Unikonta. Algae are quite diverse in a wide variety of aspects. The size of algae range from microscopic to macroscopic, with some kelps, or brown algae, reaching up to 40-50 m in length. Habitats occupied by algae are generally aquatic, with varying ranges of salinity, but there are some terrestrial groups, in soil, and on the surfaces of many objects. Some algae live in extreme temperatures, in places such as hot springs or permanent patches of snow. They also differ anatomically, cytologically, biochemically, and in the types of life cycles. The purpose of this lab is to familiarize you with several groups of algae by using representative members of each one. Keep in mind that, as knowledge about living organisms grows, new and better phylogeny and classification systems are established. 1

CYANOBACTERIA: Oscillatoria , Nostoc, and Anabaena are representative species for this group of algae (Fig. 2). Oscillatoria is a long filamentous cyanobacterium that moves by means of a gliding motion. The cells of Oscillatoria form filaments, but the cells are not dependent on one another for survival. Every cell is functionally the same. Nostoc is a cyanobacterial genus that typically forms gelatinous balls which can either float free in the Figure 1. Modern classification of eukaryotic organisms with respect to current phylogenetic data. Photosynthetic organisms covered in this lab are circled with a dashed line. 2

water or adhere to plants. Nostoc cells clump together due to the presence of an extracellular (outside the cell) sheath. Each ball of Nostoc is composed of thousands of individual cells, and these cells are also arranged in filaments. Interspersed in the filaments there are specialized, rather hollow-looking, cells called heterocysts , which are specialized in the enzymatic conversion (fixation) of nitrogen gas (N 2 ) to ammonium (NH 3 ), a form of nitrogen that is biologically useful. The cyanobacteria exhibit a wide range of colors. In addition to chlorophyll a , they also contain the blue pigment phycocyanin and the red phycoerythrin in varying amounts. These widespread microorganisms are responsible for many of the “water blooms” that occur in summer months, especially July and August. Watch this video and learn how cyanobacteria are important to aquatic ecosystem and how we can study them in lab. https://youtu.be/ZRgeh7cN9PQ Reference: American Museum of Natural History  Take a closer look at these two cynobateria Oscillatoria and Anabaena (figure 3A-C) Q. What is the colony morphology of these two cyanobacterial species having ? ________________________ Q. What is heterocyst? ___________________________________________________ _____________________________________________________________________________________ Q. How to identify a heterocyst along with the normal filament?__________________________________ _____________________________________________ Q. Among Oscillatoria and Anabaena, which you will find heterocyst _____________________ A C Figure 2. Cyanobacteria . A : Oscillatoria . B : Anabaena . C : Nostoc . B A B C Figure 3. A. Oscillatoria and B. Anabaena under microscope Reference source: https://www.algaebase.org/search/pictures/ 3

PROTISTS (ALGAE): Algae (common name) or Protists belong to the Kingdom Protista as the organisms belong to this groups are not plants, not animals or even fungi. We will learn about the organisms belong the Kingdom Protista on the basis of their pigmentation, habitat, morphology, unicellular or multicellular and their unique reproductive structures. In this lab exercise you will also learn about algae also on the basis of phylogenetic evidence as super group. (i) Supergroup Excavata Clade Euglenozoa Euglena (Fig. 3A) represent this group of flagellate mixotrophic protozoa . As all Excavata, they have a unique flagella and an “excavated” feeding groove. Their cells can change shape as they swim. Euglena also has a gullet, chloroplasts, eyespot and paramylum, where they reserve food. When grown in the dark, the chloroplasts in Euglena do not develop and cells are not green. In this case Euglena becomes a heterotroph, it surrounds a particle of food and consumes it by phagocytosis. That's why Euglena is also a mixotroph. Q. Under 100 x magnification you can see an orange pigment in Euglena what is the name of that pigment? What is it function? __________________________________ (ii) Supergroup SAR This supergroup is one of the most controversial groups out of the four. Within this supergroup, algae can be found in clades Alveolata and Stramenopila. - Clade Alveolates Dinoflagellates – Dinoflagellata Dinoflagellates have the cell wall and the two flagella. One lies in a groove around the waist or cingulim and undergoes undulating movements while the other projects forward from the logitudinal groove or sulcus for locomotion. As all other members of Alveolates clade, they have membrane-enclosed sacs (alveoli) just under the plasma membrane. Click on the video link to find out the live view of Dinoflagellate https://youtu.be/49SQMspNsoA Figure 4. Euglena under 40 x and 100 x magnification Reference source: https://www.algaebase.org/search/pictures/ 4

Q. Label the grove in the 100x magnified view of Peridinuim . ____________ Dinoflagellates are the organisms responsible for “red tides,” which are blooms or overgrowth of these organisms. Because red-tide dinoflagellates produce toxins, blooms can result in widespread destruction of fish. Many dinoflagellates are also luminescent like Noctiluca scintillans . - Clade Stramenopiles Stramenopiles clade includes some of the most important photosynthetic organisms on Earth. Most of them have a “hairy” flagellum paired with a “smooth” flagellum. Brown algae The brown algae are mainly marine. The brown color is due to a carbohydrate, laminarin . The kelps, such as Laminaria may be many meters long and can be found in the Pacific Ocean. Fucus is another common brown alga which contains air vesicles and special reproductive structures at the tips called receptacles. Click on the link https://www.algaebase.org/search/images/ and download the image of Laminaria Q. What is the name of the specialized structure, which holds the entire thallus to the ocean floor. Download the image using the link above. Diatoms –Bacillariophyceae Cell walls of Diatoms (Fig. 6) are composed of silicon dioxide (similar to glass), and consist of two separate parts (or valves) similar to a petri dish. Note the variety of form. Diatoms are divided into two types on the basis of symmetry. The first group, the pennate diatoms, is characterized by its bilateral symmetry. The second group, or the centric diatoms , possesses radial symmetry. Diatoms are perhaps economically the most important of the algae because of their role in the food cycle of Figure 5: Peridinium (40x and 100x) 5

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