Survival of Organisms in Extreme Conditions

Survival of Organisms in Extreme Conditions Organisms, known as extremophiles, survive in environments that other terrestrial life-forms find intolerable and in some cases lethal. They are evolved to survive in extreme hot niches, ice, and saline solutions, also adapting to survive in varying pH conditions; extremophiles are even found to grow in toxic waste, organic solvents, heavy metals, or in multiple habitats thought previously to be inhospitable for life. Within all the discovered extreme environmental condition, a variety of organisms have shown that they are able to not just tolerate these conditions, but they require these conditions for survival. If organisms can survive in these hostile environments on Earth it seems feasible that there could be life present in other areas of our solar system. Extremophiles are classified according to the conditions in which they grow. These sections can be further divided into two broad categories: extremophilic organisms which need these hostile conditions to survive, and extremotolerant organisms which can withstand the extreme pressure of one or multiple conditions however, grow optimally at normal and less hostile conditions. From all three domains of life, i.e. bacteria, archaea, and eukarya, extremophiles can be found. Most extremophiles are microorganisms with many of these being archaea, but protists, in the eukaryotes, have some extremophiles from the families: algae, fungi and protozoa. Archaea are the most common extremophilic domain, however are generally less versatile than bacteria and eukaryotes in at adapting to differing extreme environments. Although, some archaea are some of the most hyperthermophilic, acidophilic, alkaliphilic, and halophilic microorganisms known. The archaeal Methanopyrus kandleri strain 116 will tole rate and grow at temperatures up to 122 °C (252  °F), while the genus Picrophilus (i.e. Picrophilus torridus) are some of the most acidophilic organism, growing at a pH as low as 0.06. Bacteria like cyanobacteria, is best adapted to environments with multiple physicochemical parameters, by forming multi-layered microbial mats with other bacteria. They can survive in hypersaline conditions and alkaline lakes, which support high metal concentrations and low availability of water or xerophilic conditions, in a group of endolithic communities in stony desert regions. However, cyanobacteria is rarely found in an acidic environment at a pH lower than 6. Not only does this give insight into the origin of life on Earth, but opens up a new realm of possibilities for life elsewhere in the universe. Thermophilic bacteria are common in soil and volcanic environments i.e. hot springs. Thermophiles are thought to be one of the original organisms to have survived on earth over 3 billion years ago, in an environment with much higher temperatures, this allows possibilities to assume that a life form could be found on another planet. The ability to proliferate at growth temperature optima well above 60 °C is associated with extremely thermally stable macromolecules. As a consequence of growth at high temperature and unique macromolecular properties, thermophilic organisms can possess high metabolic rates, physically and chemically stable enzymes, and lower growth rate with a higher end product yield. Thermophilic reactions appear more stable, rapid and less expensive, and facilitate reactant activity and product recovery. Most thermophiles are anaerobes, this is due to oxygen being much less soluble at higher temperatures, therefore is not available to the organisms. Thermophiles and acidophiles have membranes that contain tetra-ether lipids, which form a rigid monolayer that is impermeable to many ions and protons. The ether type lipids are far stronger than the ester lipids found in mesophilic organisms, also the lipid layers consist of more branched and saturated fatty acids. This gives a stronger lipid complex, and is most prevalent in Archaean thermophiles. Thermophiles also stabilize their proteins, DNA, RNA and ATP, however there is no distinctive reason for how they stabilize. Though, most thermophilic organisms have more Cytosine and guanine bonds as the triple bond is a lot stronger than the Adenine Thymine bond. Thermophiles have developed unique ways of heat stabilizing their essential proteins. The protein surface energy and the hydration levels of the exposed non-polar groups are monitored and minimized by packing the hydrophobic regions into a dense core, of the protein, by the amino acids charge-charge interactions. An increased number of salt b ridges and internal networks are present, stabilizing the internal structures and an elevated amount of synthesis of chaperone proteins. Chaperone proteins unfold and help to refold proteins that are not formed properly, this is important as during hot environment there is a higher chance of misfolded proteins. The methods thermophiles employ to survive on earth could be used to survive elsewhere in our solar system. Psychrophilic organisms or psychrophiles grow best at low temperatures (freezing point of water or below) in areas such as deep sea and polar regions. The main problems for organisms in this environment is the exponential effect on the rate of biochemical reactions and the viscosity of internal and external environments, which changes significantly between 37 µÃ¢â‚¬â„¢C and 0 µÃ¢â‚¬â„¢C. (Feller Gerday, 2003; Georlette et al, 2004; Russell, 2000). In an attempt to overcome the effects on the cytoplasmic membrane, i.e. permeability and hence transportation across the membrane, there is a higher lipid concentration in the membranes containing more unsaturated, polyunsaturated, methyl-branched fatty acids, and shorter acyl-chain length. The lipid head group within the membrane is also thought to be larger. All of these adaptations increase the fluidity of the membrane and in turn survival at lower temperatures (Chintalapati et al, 2004). Another adaptation for lower temperatures is the ribosomal extract, RNA polymerase, having a larger elongation factor and the presence of peptidyl-prolyl cis-trans isomerase which have shown to retain activity near 0 °C in multiple differing psychrophilic microorganisms, like Moritella profunda, Another enzyme catalyses cis-trans prolyl isomerisation, and its high activity and overexpression at low temperatures might be important for overcoming the impaired folding protein rates. Likewise, nucleic-acid-binding proteins like Escherichia colis CspA-related proteins and RNA helicases, which are important in the transcription and translation of DNA and RNA secondary structures, are also overexpressed (Berger et al, 1996; Lim et al, 2000). The relationship between the flexibility of the membrane and the increase in activity is meant to create quite an unstable organism however, only in mesophilic environments. In a comparison of thermodynamic parameters between psychrophilic enzymes and their mesophilic homologues, at low temper ature there is a decrease in activation enthalpy, meaning a decrease in the number of enthalpy-driven reactions that have to be broken in catalysis. Organisms in this habitat are also considered to be oligotrophic as they live with lower nutrient content. Psychrophiles could use all of these adaptations in similar environments except Earth. Acidophiles and alkaliphiles are optimally adapted to acidic or alkaline pH values, acidophiles live in a higher concentration of Hydrogen ions as, Alkaliphilic organism live in a higher concentration of hydroxide ions. Acidophiles partially deflect the flow of protons into the cell by reversing the membrane potential with a reduced pore size in the membrane channels. By having a highly impermeable cell membrane organism can restrict the influx of protons, with their chemiosmostic gradient and by actively exporting protons out of the cell maintaining a habitable internal pH. In comparison to mesophiles, acidophiles have a higher proportion of secondary transporters which reduce the energy demands associated with moving protons, solutes and nutrients across the membrane. Acidophiles contain more DNA with a high proportion of protein repair mechanisms which repair at a lower pH, in B.acidocaldarius there is a higher level of cytoplasmic buffering found. In most acid environments there is a high metal content which these organisms use in their favour to stabilize their intercellular enzymes. In alkaliphilic organisms, such as Bacillus pseudofirmus and B.halodurans, oxidative phosphorylation occur to support non-fermentative growth and proton-coupled ATP synthases occurs, using proton-motive force (PMF) but mostly from the sodium-ion gradient. A major adaption of the alkaliphiles for surviving in their environments is within the diversity of their enzymes. Mesophilic organisms produce enzymes with similar activity however, do not have the same enzymatic capacity to cope with the increase pH. An internal pH is maintained by the active and passive regulation mechanisms across the membrane, actively removing the hydroxide ions. The addition of cytoplasmic pools of polyamines and low membrane permeability, with sodium ion channels actively regulates these levels. Alkaliphillic bacteria also compensate for the high levels by having a high membrane potential or coupling Na+ expulsion through the ETC. All of these processes used could be utilized by interplanetary organism. Throughout our solar system there are many environments where some of these extremophiles could use their adaptations to survive. The main necessity for life would be the presence of even a minimal supply of water. In our solar system there are environments thought to be able to support life. Titan, one of Saturns moons, has sustainable atmosphere composed primarily of nitrogen, similar to earths. There are many ammonia and methane lakes on titan that theoretically could combine, in an electrically charged environment, to make an organic habitat. Thermophiles that also contain sulfureted properties could survive there as they survive in similar conditions in the deep ocean hot springs. Enceladus, another of Saturns moons has an abundant supply of water vapour geysers and Europa, one of Jupiters moons, both are thought to be entirely covered in ice. Psychrophiles and Alkaliphilic or Acidophilic organism could adapt to live in this environment. Enceladus is considered an active water w orld with oceans with Europa thought to have subglacial water systems under the ice layer. Models of Enceladus predict the oceans to be a solution of Na-Cl-CO3 with a pH of 11 to 12. This is a similar environment to Lake Shala in the Rift Valley Lakes, with a high alkaline pH and due to it being the deepest lakes on earth, a cold temperature at its lowest depth. Europa has a highly acidic water system and due to the total coverage of ice on the surface of the moon, any organism able to survive there must also be anaerobic. Overall, on earth we have many extreme environments which are considered lethal to most organism but are home to extremophiles, such as thermophiles, psychrophiles, acidophiles and alkaliphiles. From the way many of these organism adapt to survive on earth it is feasible that organism with similar adaptations could be present or could survive elsewhere in our solar system, in similar environments.

Winston Churchill :: essays research papers

Those eleven burning words summed up the nature of Britain's war, turned Britain's back on the weaknesses of the past, set her face toward the unknown future. Because of them the rest of that speech has been forgotten. It should not be forgotten, for it is not only a great example of Winston Churchill's eloquence, but the epitome of the movement which he leads. After a brief report on the formation of his Government, Winston Churchill said: "You ask, what is our policy? I say it is to wage war by land, sea and air--war with all our might and with all the strength God has given us--and to wage war against a monstrous tyranny never surpassed in the dark and lamentable catalogue of human crime. That is our policy. "You ask, what is our aim? I can answer in one word. It is victory. Victory at all costs. Victory in spite of all terrors. Victory, however long and hard the road may be, for without victory there is no survival. "Let that be realized. No survival for the British Empire, no survival for all that the British Empire has stood for, no survival for the urge, the impulse of the ages, that mankind shall move forward toward his goal." December 31, 1940, was not only the end of a year; it was the end of a decade--the most terrifying of the 20th Century. The decade which ended in 1920 had seen a war that was to prove inconclusive. It had seen a revolution that was to lie quiescent after establishing itself in the largest country of the world. The decade which ended in 1930 was one of confusion and wasted energy--the wasted energy of gambling and gin-drinking in the U.S., of civil war in the Far East, of misdirected revolutionary effort from the U.S.S.R., of the attempt in Europe to hold resurgent peoples in check. The decade which ended this week saw the failure of that attempt and the unleashing of ruthless war. It saw the Far East's battle of warlords turn into a war for the supremacy of one people. It saw the U.S. turn to a feverish effort to protect itself and its neighbors. It saw, in the Battle of Britain, the life-&-death struggle of the greatest empire the world has ever known. The Candidates of 1940. No artist, no athlete, no scientist, only a man whose place was on the stage of world politics, could be Man of 1940--last and stormiest year of a stormy decade.

Overpopulation: Population Growth and Birth Rate

Although most of us live a prosperous life with no worries, there are several issues that we are currently facing that will eventually be more and more clear as time goes on. One of these problems is most damaging, in my opinion, to our way of life if we do nothing about it. The issues I am speaking of is the problem of overpopulation. This is a developing crisis and it has plagued most of the world. An area is considered overpopulated if â€Å"its population can't be maintained without rapidly depleting nonrenewable resources and without destroying the environment which supports the population.†(Brown,Gardner,Halweil, Beyond Malthus,19).The problems that arise due to overpopulation could lead to a fatal epidemic that could wipe out the whole human race. So the question remains: Are we facing overpopulation here in the Middle East? And how do we tackle such problems? The answer to this question is a short simple â€Å"Yes† but the solution to this problem is much longer than a one word answer. As such, overpopulation is existent here in the Middle East and countries should identify, analyze and control it immediately.Although I do believe we are facing the crisis of over population, one might ask what exactly can be defined as overpopulation. Through common sense, overpopulation occurs when the number of people living in a certain region, who depend on resources for survival, is significantly bigger than the amount of resources available to them. This as a result, can lead to people living poorer and unhealthier lives compared to others. Currently the world is increasing by 80 million people per year (Stefoff 16). â€Å"Population is determined by the interplay of two factors.One is the birth rate, or the number of people being born, and the other is death rate, or the number who die. The difference between the two is called the rate of natural increase† (Stefoff 25). So let's say the birth rate is 5 children per second, and the death rate is 2 deaths per second. The population in this case will increase by 3 per second. Overpopulation occurs when this number grows rapidly. I would like to introduce the Malthusian theories, which explains why overpopulation occurs (Stetoff 34).Basically the theory explains that since population increases geometrically (1-2-4-8-16) and while resources can only grow arithmetically (1-2-3-4-5), overpopulation will occur. As such, any country with a geometric increase in population will eventually face this problem and that country should take drastic measures to solve this problem of overpopulation. Egypt, as example, is facing the problem of overpopulation. According to recent statistics the population of Egypt right now is 81 million, while in 1951 the population was 20 million (Mountjoy 121).That means the population more than quadrupled over a period of just sixty 60 years. Clearly such drastic increases can't go unseen and since it clearly shows a exponential growth one can expect t he population of Egypt to increase by a larger factor in the upcoming year. Given that the country is 97% desert (Mountjoy 121), one can assume that expansion of agriculture is strictly limited. With this course of overpopulation, the country's agricultural expanding won't be able to catch up with such an increase of population.The reason behind this overpopulation is not only due to lack of government enforcement on child policies, but in my opinion, also due to the Egyptian mentality that having more children will result in God rewarding them. I have come to learn this through friends who claim that the average Egyptian will have an average of 6 children. As result of this, Egypt should take steps towards resolving this overpopulation crisis as soon as possible or prepare to face such consequences. Since we can acknowledge the existence of overpopulation now, we must therefore find solutions to this problem.At this rate, the population of earth will reach 9 billion by 2050 which i s a 15% increase from the current population. If we let this problem go untouched, we will reach a point where solving overpopulation will technically be impossible. As such, tackling this problem as soon as possible, will make these solutions easier to implement. Although one such way to avoid overpopulation is do what China did: implement a one-child policy, in which the family can't have more than one child (Engelman). Although this solution will work, this path must not be taken because it deprives a human of their rights and a solution like this isn't practical.One technique Robert Engelman suggested was â€Å"elevating woman’s status and increasing access to contraceptive services, so that essentially all births result from intended pregnancies†. Only 4 out of 5 pregnancies are intended (Engelman) and if a global movement was enforced to eliminate all unwanted pregnancies, any overpopulated country will see an immediate fall in population growth and within a few decade the population growth will subsequently decline. This increase of accessibility to contraceptive measures will definitely help Egypt battle their overpopulation problem.This comes back to the question: Are we facing the problem of overpopulation in the Middle East, and I assure you, yes we are. This research paper was dedicatedly made to give awareness of the rising problem of overpopulation, especially in the Middle East. Overpopulation occurs when a country's population is much more than their provided resources, causing resources to be depleted much faster and the inability of the country to sustain it's population. Through research, it was concluded that Egypt is one example of a Middle Eastern country facing overpopulation at a very high rate.Therefore, a country cannot look past this overpopulation problem and must prioritize their efforts towards finding solutions to tackle this problem. Although a bunch of solutions exist, some of them should not be approached as they contradict with human rights and human freedom. One suggested solution to this problem is to elevate woman’s status and increase their accessibility to contraceptive measures in order to avoid any unwanted pregnancies. I can conclude that the existence of overpopulation is imminent, but every problem has a solution, and countries should tackle this problem without second thought.

Analysis Of The Argument And Evidence Of The Movie Crash

Summary of the argument and evidence Minsky argues that there is Ð ° fundamental and inherent instability in our economy that tends towards Ð ° speculative boom. Ð ° human being is fundamentally Ð ° momentum investor as argued rather than Ð ° value investor. Hence during times of speculative boom three types of market players are prominent namely hedgers , speculators and Ponzi investors. Ponzi investors are those which rely on the increase in asset price to refinance their existing debt. Hence Ð ° Ponzi investor is safe as long as the asset prices tend to rise. This period of mammoth rise in asset prices is triggered by the herd mentality and the fundamental nature of humans being momentum investors rather than value buyers. Unlike other works†¦show more content†¦Furthermore , for coherence to reign in Ð ° market , substitution principle must apply which states that higher relative price of Ð ° commodity tends to discourage buyers from buying it whereas lower rela tive price has the exact opposite effect on the appetite of the buyer. If the substitution principle is strong enough , then decentralised markets are reliable for efficient allocation of output to households and factor inputs to businesses. This leads us somewhere to the idea of Ð ° Pareto optimal equilibrium. â€Å"Equilibrium† would not be the right term to use in Minsky’s context as instead of equilibrium , he proposed â€Å"periods of tranquility† which are characterised by robust financial systems and innovations much like what preceded the 2008 subprime mortgage crisis. But phases of tranquility are just calm before the storm as tranquility encourages more risk-taking that increases incomes even as it disrupts conditions necessary for â€Å"coherency† and â€Å"tranquility†. Therefore , according to this theory the market forces that operate in the time of tranquility are what push the system towards instability so that even if an equilibri um is achieved for some time, it’ll set of behavioural responses that will quickly displace the economy from equilibrium. While Minsky credits Keynes for pointing out that the aggregate quantity of investment was self enforcing on the economy through the multiplier effect , he went one stepShow MoreRelatedSociopath Portrayed In Tv And Movies Vs. Real Life. Name.1683 Words   |  7 Pagesdisorder characterized by at least two distinct and relatively enduring identities. It causes a lack of connection in a person’s thoughts’ memories, feelings, actions, or sense of identity. 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