EUBACTERIA Agrobacterium Agrobacterium is a genus of Gram-negative bacteria that uses horizontal gene transfer to cause tumors in plants. Agrobacterium tumefaciens is the most commonly studied species in this genus. Agrobacterium is well known for its ability to transfer DNA between itself and plants, and for this reason it has become an important tool for genetic engineering. A. tumefaciens causes crown-gall disease in plants. The disease is characterised by a tumour-like growth or gall on the infected plant, often at the junction between the root and the shoot. Tumors are incited by the conjugative transfer of a DNA segment (T-DNA) from the bacterial tumour-inducing (Ti) plasmid. Escherichia Escherichia is a genus of Gram-negative, nonspore forming, facultatively anaerobic, rod-shaped bacteria. In those species which are inhabitants of the gastrointestinal tracts of warm-blooded animals, Escherichia species provide a portion of the microbially derived vitamin K for their host. A number of the species of Escherichia are pathogenic. While many Escherichia are commensal gut flora, particular strains of some species are known as the most common cause of urinary tract infections, significant sources of gastrointestinal disease, ranging from simple diarrhea to dysentery-like conditions. Rhizobium Rhizobium is a genus of Gram-negative soil bacteria that fix nitrogen. Rhizobium species form an endosymbiotic nitrogen-fixing association with roots of legumes. The bacteria colonize plant cells within root nodules, where they convert atmospheric nitrogen into ammonia and then provide organic nitrogenous compounds such as glutamine or ureides to the plant. The plant, in turn, provides the bacteria with organic compounds made by photosynthesis. Thus, it acts as a natural fertilizer for the plants. Salmonella Salmonella is a genus of rod-shaped (bacillus) Gram-negative bacteria of the Enterobacteriaceae family. S. enterica subspecies are found worldwide in all warm-blooded animals, and in the environment. S. bongori is restricted to cold-blooded animals, particularly reptiles. Strains of Salmonella cause illnesses such as typhoid fever, paratyphoid fever, and food poisoning (salmonellosis). Anabaena Anabaena is a genus of filamentous cyanobacteria that exist as plankton. They are known for nitrogen-fixing abilities, and they form symbiotic relationships with certain plants, such as the mosquito fern. They are one of four genera of cyanobacteria that produce neurotoxins, which are harmful to local wildlife, as well as farm animals and pets. Production of these neurotoxins is assumed to be an input into its symbiotic relationships, protecting the plant from grazing pressure. They have heterocysts, which convert nitrogen into ammonia. Certain species of Anabaena have been used on rice paddy fields, proving to be an effective natural fertilizer. Under nitrogen-limiting conditions, vegetative cells differentiate into heterocysts at semiregular intervals along the filaments. Heterocyst cells are terminally specialized for nitrogen fixation. The interior of these cells is micro- oxic as a result of increased respiration, inactivation of O2-producing photosystem (PS) II, and formation of a thickened envelope outside of the cell wall. Nitrogenase, sequestered within these cells, transforms dinitrogen into ammonium at the expense of ATP and reductant—both generated by carbohydrate metabolism, a process supplemented, in the light, by the activity of PS I. Carbohydrate, probably in the form of glucose, is synthesized in vegetative cells and moves into heterocysts. In return, nitrogen fixed in heterocysts moves into the vegetative cells, at least in part in the form of amino acids. Bacillus Gram‐positive, rod shaped, obligate or facultative aerobes, produce dormant endospores (dehydrated thick membrane enclosed shells) when under stress (anthrax). Streptomyces Streptomycetes are Gram-positive, and have genomes with high GC content. Found predominantly in soil and decaying vegetation, most streptomycetes produce spores, and are noted for their distinct "earthy" odor that results from production of a volatile metabolite, geosmin. Streptomycetes are characterised by a complex secondary metabolism. They produce over two-thirds of the clinically useful antibiotics of natural origin (e.g., neomycin, cypemycin, grisemycin, bottromycins and chloramphenicol). Streptomycetes are infrequent pathogens, though infections in humans, such as mycetoma, can be caused. Thermus Thermus is a genus of thermophilic bacteria. ARCHAEA Methanobacterium Anaerobic, non‐motile, use carbon dioxide to oxidize hydrogen gas to make methane, rod shaped, found in the GI tract of herbivores. Halobacterium The genus Halobacterium ("salt" or "ocean bacterium") consists of several species of the Archaea with an aerobic metabolism which requires an environment with a high concentration of salt; many of their proteins will not function in low-salt environments. They grow on amino acids in their aerobic conditions. Their cell walls are also quite different from those of bacteria, as ordinary lipoprotein membranes fail in high salt concentrations. They reproduce using binary fission (by constriction), and are motile. Thermoplasm Thermoplasma is a genus of archaea. It belongs to the Thermoplasmata, which thrive in acidic and high- temperature environments. Thermoplasma are facultative anaerobes and respire using sulfur and organic carbon. They do not contain a cell wall but instead contain a unique membrane composed mainly of a tetraether lipoglycan containing atypical archaeal tetraether lipid attached to a glucose- and mannose-containing oligosaccharide. This lipoglycan is presumably responsible for the acid and thermal stability of the Thermoplasma membrane. Sulfolobus Sulfolobus species grow in volcanic springs with optimal growth occurring at pH 2-3 and temperatures of 75-80 °C, making them acidophiles and thermophiles respectively. Sulfolobus cells are irregularly shaped and flagellar. EUKARYA PROTISTA Euglenozoa Euglena Euglena is a genus of single-celled flagellate Eukaryotes. Species of Euglena are found in fresh and salt waters. Most species of Euglena have photosynthesizing chloroplasts within the body of the cell, which enable them to feed by autotrophy, like plants. However, they can also take nourishment heterotrophically, like animals. Thus, they are mixotrophs. They possess chloroplasts through secondary endosymbiosis of green algae (thus their chloroplasts have three membranes). No cell wall, but pellicle made of proteins. Pyrenoids store paramylon (carbohydrate similar to starch). It has a crystalline rod in the flagella. Trypanosoma Trypanosoma is a genus of kinetoplastids (class Kinetoplastida), a group of unicellular, parasitic, flagellate protozoa. Most trypanosomes are heteroxenous (requiring more than one obligatory host to complete life cycle) and most are transmitted via a vector. The majority of species are transmitted by blood-feeding invertebrates, but there are different mechanisms among the varying species. In an invertebrate host, they are generally found in the intestine, but normally occupy the bloodstream or an intracellular environment in the mammalian host. The mitochondrial genome of the Trypanosoma, as well as of other kinetoplastids, known as the kinetoplast, is made up of a highly complex series of catenated circles and minicircles and requires a cohort of proteins for organisation during cell division. Stramenopiles Paheophyta (Brown Algae) Sargasum Any number of the normally benthic species may take on a planktonic, often pelagic existence after being removed from reefs during rough weather. Possess xanthophyll called fucoxanthin, giving distinctive color. Body called a thallus with holdfast “root” and stipe “Stem”. Pneumatocysts provide buoyancy. Bacillariophyta (Diatoms) Diatoma Diatoms are a major group of algae, and are among the most common types of phytoplankton. Diatoms are unicellular, although they can form colonies in the shape of filaments or ribbons. Diatoms are producers within the food chain. A unique feature of diatom cells is that they are enclosed within a cell wall made of silica (hydrated silicon dioxide) called a frustule. Only male gametes of centric diatoms are capable of movement by means of flagella. Diatom communities are a popular tool for monitoring environmental conditions, past and present, and are commonly used in studies of water quality. Sexual reproduction involves the formation of an auxospore. Four‐membraned chloroplasts (all stremenophiles). Alveolates Apicomplexa Plasmodium While a large portion of the apicomplexans are known parasites of virtually all vertebrates including humans, they are equally diverse in both marine and terrestrial invertebrates. The apicoplast is a remnant non- photosynthetic plastid characteristic of apicomplexans consisting of a 35kb circular genome. The basic life cycle of the apicomplexan parasite is typically complicated. Generally, there are four transformations to complete the cycle: the zygote, a sporozoite, a merozoite, and a gametic stages. The typical lifecycle of apicomplexa is well established as they all undergo a series of asexual and sexual reproduction involving either one or two hosts whereby a diploid zygote is formed by the union of gametes. It then undergoes a meiotic division to form infective haploid sporozoites. Within the body, sporozoites are thought to target specific cells by the use of a range of molecular armaments which include surface adhesions such as