What are actinomycetes?
Actinomycetes are a group of Gram-positive bacteria with high G+C ratio. They include some of the most common soil life, playing an important role in decomposition of organic materials, such as cellulose and chitin and thereby play a vital part in organic matter turnover and carbon cycle. Thus replenishing the supply of nutrients in the soil and is an important part of humus formation. Actinobacteria are well known as secondary metabolite producers and hence of high pharmacological and commercial interest. In 1940 Selman Waksman discovered that the soil bacteria he was studying made actinomycin, a discovery which granted him a Nobel Prize. Since then hundreds of naturally occurring antibiotics have been discovered in these terrestrial microorganisms, especially from the genus Streptomyces. Other Actinobacteria inhabit plants and animals, including a few pathogens, such as Mycobacterium, Corynebacterium, Nocardia, Rhodococcus and a few species of Streptomyces. Genomes of 44 different strains of Actinobacteria from different genera are either already sequenced or underway right now. Some Actinobacteria form branching filaments, which somewhat resemble the mycelia of the unrelated fungi, among which they were originally classified under the older name Actinomycetes. Most members are aerobic, but a few, such as Actinomyces israelii, can grow under anaerobic conditions. Unlike the Firmicutes, the other main group of Gram-positive bacteria, they have DNA with a high GC-content and some Actinomycetes species produce external spores. Representative genera include: Actinomyces Arthrobacter Corynebacterium Frankia Micrococcus Micromonospora Mycobacterium Nocardia Propionibacterium Streptomyces
Why do bacteria produce pigments?
There are many reason the bacteria to produce pigments.1. Phototsynthesis2. UV protection3. Defense mechanisms4.Secondary metabolites for storage of energy5. StressIt varies with environment differs in marine, terrestrial and space.
What are some types of bacteria which have a complex secondary metabolism?
Hmm, interesting question. You obviously already know that by far, most clinically relevant antibiotics (and other secondary metabolites used as drugs) are produced by the actinos - many are produced by fungi, as well, but you're specifically interested in bacteria, I guess. Most species will produce one sort of antimicrobial or another, I guess - it must give some sort of selective advantage in natural environments. E. coli produces colicins, Bacillus makes subtilisin (and possibly a few others - can't remember just now), Pseudomonas species make phenazines and pyoveridins (and again, I think others - don't remember at the moment). Most, if not all, bacteria will make one or more siderophores (like pyoveridin), for scavenging iron from the environment - these are often produced using similarish pathways to antibiotic production, and similarly, give the producing bacteria a competitive edge (in terms of growth, not in terms of killing neighbouring bacteria). A lot of projects have focused on taking samples from soil, or marine, or other environments, and screening for antimicrobials/secondary metabolites - and always, or nearly always, finding something (it's finding something novel that's harder, of course). See, for example: Genome mining reveals unlocked bioactive potential of marine Gram-negative bacteria.The Kolumbo submarine volcano of Santorini island is a large pool of bacterial strains with antimicrobial activity.Investigation of bacteria with polyketide synthase genes and antimicrobial activity isolated from South China Sea sponges.Antibacterial activity of marine culturable bacteria collected from a global sampling of ocean surface waters and surface swabs of marine organisms.So, in short, you'll generally find secondary metabolism everywhere. Some, though not all, of these metabolic pathways are expressed under laboratory conditions and lead to the production of useful (to us) compounds. (Others are silent, or cryptic, under the growth conditions used in the laboratory.) Many of these pathways lead to the production of small molecules for which we don't know the function, or which are not useful to us, but which are presumably important for the producing organism in some way.
What are the final product of Carbohydrates proteins and fats after their digestion?
The end result of carbohydrates is glucose that is converted into energy or stored as glycogen. Protein is converted into amino acids which are the instructions that drive all tissue functions, amino acids tell cells what to do. Fats are converted into lipids that circulated in the blood stream and are essential to metabolic functions.
List down at least two ecological importance of cyanobacteria. ?
Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of bacteria that obtain their energy through photosynthesis. The name "cyanobacteria" comes from the color of the bacteria (Greek: κυανός (kyanós) = blue). They are a significant component of the marine nitrogen cycle and an important primary producer in many areas of the ocean, but are also found on land. Stromatolites of fossilized oxygen-producing cyanobacteria have been found from 2.8 billion years ago. The ability of cyanobacteria to perform oxygenic photosynthesis is thought to have converted the early reducing atmosphere into an oxidizing one, which dramatically changed the life forms on Earth and provoked an explosion of biodiversity. Chloroplasts in plants and eukaryotic algae have evolved from cyanobacteria via endosymbiosis. Certain cyanobacteria produce cyanotoxins like anatoxin-a, anatoxin-as, aplysiatoxin, cylindrospermopsin, domoic acid, microcystin LR, nodularin R (from Nodularia), or saxitoxin. Sometimes a mass-reproduction of cyanobacteria results in algal blooms. The unicellular cyanobacterium Synechocystis sp. PCC6803 was the third prokaryote and first photosynthetic organism whose genome was completely sequenced.[8] It continues to be an important model organism. The smallest genomes have been found in Prochlorococcus and the largest in Nostoc punctiforme . Those of Calothrix spp. are estimated at as large as yeast. At least one secondary metabolite, cyanovirin, has shown to possess anti-HIV activity. See hypolith for an example of cyanobacteria living in extreme conditions. Some cyanobacteria are sold as food, notably Aphanizomenon flos-aquae and Arthrospira platensis (Spirulina). It has been suggested that they could be a much more substantial part of human food supplies, as a kind of superfood. Along with algae, some hydrogen producing cyanobacteria are being considered as an alternative energy source, notably at Oregon State University, in research supported by the U.S. Department of Energy, Princeton University, Colorado School of Mines, Ohio University as well as at Uppsala University, Sweden.
Could there a bigger problem caused by carbon dioxide than global warming?
To answer the question, it's unclear what is actually worse--global warming or ocean acidification. However, if ocean acidfication continues to worsen, there will be severe consequences--like the decimation of coral reefs and calcareous phytoplankton. Fisheries can collapse due to the destruction of the food chain, and if all the calcareous organisms are gone, we no longer have a CO2 solubility pump. Calcareous organisms are responsible for sequestering a great deal of carbon in their CaCO3 shells and then depositing them on the seafloor when they die. Thus, if these organisms disappear, the oceans will be unable to absorb as much CO2. This will only worsen global warming. Now to address some of the ignorant responses... Alex: Overfishing does not cause ocean acidification. That claim is as absurd as me saying that the ignorant comments here are lowering ocean pH. Ocean acidification is not a misnomer. You are confused. Acidification is a relative description. Seawater is still basic compared to pure water (pH = 7), but it is acidic compared to current trends and past conditions. Catmandew: The formation of CaCO3 is a major mechanism of carbon sequestration, but you are wrong to assume that all the dissolved CO2 is removed in this way. CaCO3 precipitation depends on the carbonate equilibria, the pH, and water column CaCO3 saturation. Lower the pH of seawater, and you will be able precipitate less CaCO3. CaCO3 precipitation is also low where it is undersaturated, and acidic conditions only exacerbate this. Carbonate equilibria is as follows. CO2 + 3 H2O <---> H2CO3 + 2 H2O <---> H3O^+ + HCO3^2- + H2O <---> 2H3O + CO3^2- Seawater must always maintain a constant equilibrium proportion of the carbonate species. When seawater has an excess of hydronium ions (relative to equilbrium concentrations), carbonate is released from CaCO3 to restore equilibrium. Humans have increased CO2 in the atmosphere, and the increased concentrations are causing ocean pH to decrease. And CaCO3 is dissolving to compensate. Simple as that. The oceans have always been exchanging CO2 with the atmosphere, but the current ocean acidification is anthropogenic, not natural.
How do you calculate the mass of carbon atoms in CO2?
You use the relative atomic mass of the atoms.Carbon has a relative atomic atomic mass of 12. Oxygen has a relative atomic mass of 16, so two of them is 32.Hence in whichever mass CO₂ you choose, there will be (12 ÷ (12 + 32)) × 100% = 27.3% to 3sf.