Effect of Reducing Agents on the Growth of Magnetospirilla

Effect of Reducing Agents on the Growth of Magnetospirilla Shubhashri Chakraborthy, Pauline Shekina, Upasana Dey and Suthindhiran Krish Abstract: Magnetotactic Bacteria are a fascinating group of microorganisms. Magnetospirilla is a microaerophilic bacterium. The effect of reducing agents varies with the cell depending on the properties of the reagent. They also produce different redox potentials which force a substrate to follow specific metabolic pathway in order to change the product or rate of the reaction. So it is essential to study the effect of reducing agents on the growth of Magnetospirilla. Two strains of this bacterium, MSR-1 and RJS-1 were selected for the study. Reducing agents like Ascorbic Acid, Cysteine and Glutathione were prepared in various concentrations and the bacteria were cultured. The ideal concentration of the reducing agents required for the growth of these two strains was identified. Glutathione at the concentration 0.250mg/ml is found to be ideal for the growth of MSR-1 and Cysteine at the concentration of 0.250mg/ml is found to be ideal for the growth of RJS-1 strain of Magnetospirilla Keywords: Magnetotactic bacteria; Ascorbic Acid; Cysteine; Glutathione; Reducing agents. Introduction: Magnetotactic bacteria (orMTB) are a  polyphyletic  group of  bacteria that orient along themagnetic field lines of Earth’s magnetic field with the help of organelles called magnetosomes. Magnetosomes are iron crystals of magnetite or greigite. The movement of microorganisms in response to the magnetic characteristics of the environment is known as  magnetotaxis. Many efforts have been made to optimize the growth conditions of MTB.[4] Magnetospirilla are facultative anaerobic magnetic bacterium. Reducing agents can have very different effects on the microbial cells depending on the properties of the reagent and of the properties of the cell itself. Reducing agents can produce different redox potentials which might be force a substrate to follow a specific metabolic pathway in order to change the rate or product of the reaction.[6] Previous studies showed that changing the redox environment had a strong impact in the applications of Magnetospirilla. Therefore we studied the effect of different reducing agents at different concentrations on the growth of Magnetospirilla. Materials and Methods: Culturing the bacteria Two strains of Magnetospirilla, MSR-1 (DSMZ, Germany) and RJS-1(Marine Biotechnology Lab, VIT University) were grown in liquid Magnetic Spirillum Growth Medium (MSGM).[1] A stock of 500ml of the MSGM media was prepared without reducing agents and Resazurin. 7ml of the media were transferred in small vials and it was purged with nitrogen gas for 3 minutes to provide microaerophilic condition. The vials were sealed with butyl rubber septa and aluminium centre holed caps. These vials were autoclaved at 121 °C for 15 minutes. Stock solution of the reducing agents Ascorbic Acid, Cysteine, Glutathione and Sodium Sulfide (10mg/10ml) were prepared and filter sterilized. Heat sensitive materials such as vitamins were also filter sterilized. 70ÃŽ ¼l of filtered vitamin solution and 14ÃŽ ¼l of filtered ferric quinate solution were taken in sterile eppendorf tubes. Different concentrations of reducing agents (0.125mg/ml, 0.250mg/ml, 0.375mg/ml and 0.500mg/ml) were also taken in the eppendorf t ubes containing the vitamin and ferric quinate solutions. Using sterile needles and syringes these solutions were transferred into the vials. These vials were incubated at 37 °C in a shaker. Checking the growth of the bacteria The growth of the bacteria were observed using spectrophotometer. Optical Density (OD) was taken at 595nm in 24, 26, 29, 38, 44 and 48 hours of incubation. The values are plotted in graph to find the maximum growth rate. Results and Discussion: A graph was plotted against time in hours and the OD values taken for different concentrations of reducing agents. Figure 1. Graph showing the growth of Magnetospirilla (MSR-1) at various concentrations of Ascorbic Acid. The growth of MSR-1 was maximum at the concentration 0.500mg/ml of Ascorbic acid. Figure 2. Graph showing the growth of Magnetospirilla (MSR-1) at various concentrations of Cysteine. The growth of MSR-1 was maximum at the concentrations 0.250mg/ml of Cysteine. Figure 3. Graph showing the growth of Magnetospirilla (MSR-1) at various concentrations of Glutathione. The growth of MSR-1 was maximum at the concentration 0.250mg/ml of Glutathione. Figure 4. Graph showing the growth of Magnetospirilla (MSR-1) at various concentrations of Sodium Sulfide. The growth of MSR-1 was maximum at the concentration 0.500mg/ml of Sodium Sulfide. Comparing all the OD values the growth of MSR-1 was maximum at the concentration 0.250mg/ml of Glutathione. Figure 5. Graph showing the growth of Magnetospirilla (RJS-1) at various concentrations of Ascorbic Acid. The growth of RJS-1 was maximum at the concentration 0.375mg/ml of Ascorbic Acid. Figure 6. Graph showing the growth of Magnetospirilla (RJS-1) at various concentrations of Cysteine. The growth of RJS-1 was maximum at the concentration 0.250mg/ml of Cysteine. Figure 7. Graph showing the growth of Magnetospirilla (RJS-1) at various concentrations of Glutathione. The growth of RJS-1 was maximum at the concentration 0.375mg/ml of Glutathione. Figure 8. Graph showing the growth of Magnetospirilla (RJS-1) at various concentrations of Sodium Sulfide. The growth of RJS-1 was maximum at the concentration 0.500mg/ml of Sodium Sulfide. Comparing all the OD values the growth of RJS-1 was maximum at the concentration 0.250mg/ml of Cysteine. Our studies showed that optimal concentration of reducing agents showed increased growth. When the concentration of reducing agents is increased further it inhibits the growth because of toxicity. Optimal concentration of reducing agents reduces the lag time and enhances the cell density. Conclusion: There are many other reducing agents which are used for growing various species of Magnetotactic bacteria. From the results we got it is suggested that Glutathione at the concentration 0.250mg/ml is ideal for the growth of MSR-1 and Cysteine at the concentration of 0.250mg/ml is ideal for the growth of RJS-1 strain of Magnetospirilla. References: [1] Blakemore R P, Maratea D and Wolfe R S, â€Å"Isolation and Pure Culture of a Freshwater Magnetic Spirillum in Chemically Defined Medium,† Journal of Bacteriology, 140(2), 720, 1979. [2] Cody Nash, â€Å"Mechanisms and Evolution of Magnetotactic Bacteria,† 2008. [3] Damien Faivre and Dirk Schuler, â€Å"Magnetotactic Bacteria and Magnetosomes,† Chem.Rev, 108, 4875–4898, 2008. [4] John F. Stolz, â€Å" Magnetosomes,† Journal of General Microbiology, 139, 1663-1670,1993. [5] Tadashi Matsunaga and Toshifumi Sakaguchi, â€Å" Molecular Mechanism of Magnet Formation in Bacteria,† Journal of Bioscience and Bioengineering, 90, 1-13, 2000. [6] Xiangqian Li, Qilei Wang and Yemin Xue, â€Å" On the Change in Bacterial Growth and Magnetosome Formation for Magnetosprillum Sp. Strain AMB-1 Under Different Concentrations of Reducing Agents,† Jorunal of Nanoscience and Nanotechnology,13, 1392-1398, 2013. [7] Yoshihito Uchino and Suzuki Ken-Ichiro, â€Å"A Simple Preparation of Liquid Media for the Cultivation of Strict Anaerobes,† Journal of Petroleum and Environmental Biotechnology, S3-001, 2157-2160, 2011.

Hamlet is Inhuman :: Shakespeare Hamlet

Hamlet is Inhuman Hamlet is inhuman. He has seen through humanity. And this inhuman cynicism, however justifiable in this case, on the plane of causality and individual responsibility, is a deadly and venomous thing. Instinctively the creatures of earth-Laertes, Polonius, Ophelia, Rosencrantz and Guildenstern, league themselves with Claudius: they are of his kind. They sever themselves from Hamlet. Laertes sternly warns Ophelia against her intimacy with Hamlet, so does Polonius. They are, in fact, all leagued against him, they are puzzled by him or fear him: he has no friend except Horatio, and Horatio, after the ghost scenes, becomes a queer shadowy character who rarely gets beyond "E'en so, my lord," "My lord-," and suchlike phrases. The other persons are firmly drawn, in the round, creatures of flesh and blood. But Hamlet is not of flesh and blood, he is a spirit of penetrating intellect and cynicism and misery, without faith in himself or anyone else, murdering his love of Ophelia, on the brink of insanity, taking delight in cruelty, torturing Claudius, wringing his mother's heart, a poison in the midst of the healthy bustle of the court. He is a superman among men. And he is a superman because he has walked and held converse with Death, and his consciousness works in terms of Death and the Negation of Cynicism. He has seen the truth, not alone of Denmark, but of humanity, of the universe: and the truth is evil. Thus Hamlet is an element of evil in the state of Denmark. The poison of his mental existence spreads outwards among things of flesh and blood, like acid eating into metal. They are helpless before his very inactivity and fall one after the other, like victims of an infectious disease. They are strong with the strength of health -but the demon of Hamlet's mind is a stronger thing than they. Futilely they try to get him out of their country; anything to get rid of him, he is not safe. But he goes with a cynical smile, and is no sooner gone tha n he is back again in their midst, meditating in graveyards, at home with Death. Not till it has slain all, is the demon that grips Hamlet satisfied.

Drugs Addiction

Al Akhawayn University Center for Academic Development Information Literacy Skills 1212 Fall 2010 The causes of drugs addiction Prepared by: ABDELAZIZ Under the supervision of: Dr. AHMED KABEL The causes of drugs addiction: AddictionNowadays, drugs addiction is considered as one of the most widespread phenomena in our modern societies. Everyone in this modern world has become aware of the dangerous consequences of being drug addicted, yet opium, cocaine, marijuana, cannabis, and many other kinds of drugs have been used for centuries and are still widely used today by a large proportion of people from different age, sex, and economic status. But, before looking at the factors that push people to take drugs, let us first define drug addiction.According to Mayo Foundation for Medical Education and Research (MFMER), â€Å"Drug addiction is a dependence on a street drug or a medication. When you're addicted, you may not be able to control your drug use and you may continue using the drug despite the harm it causes. Drug addiction can cause an intense craving for the drug. You may want to quit, but most people find they can't do it on their own. † In fact, people often underestimate the complexity of drugs addiction and the fact that it has become a contemporary illness that is similar to other chronic diseases such as diabetes, asthma, or heart disease.Moreover, many people used to think that people addicted to drugs were just morally weak; hence, they believe that drug abusers are able to stop â€Å"this habit† if they are only willing to do so. However, recent scientific advances have allowed us to know much more about how exactly addictive drugs impact and change the brain, and how stopping drug abuse is very complex and not only a matter of willpower. But, the real problem is that many people still do not have a clear idea about the causes behind addiction.For most of them, according to Hamid Ghodse, â€Å"the cause or causes of drug dependence ar e not known, or more specifically, it is not known why do some people become addicted while others in the same situation do not† (10). The causes of drugs addiction are numerous and very attached with each other, but the most important factors that interact to lead to this phenomenon are: person’s biology, social environment, and age or stage of development.It is, obviously, very important to determine whether genetic factors play a significant role in the process of addiction or not at all. Actually, finding genes which predispose to drugs addiction may undoubtedly be very helpful since it will â€Å"aid in the identification of the biological processes involved in the addiction condition and ultimately allow the development of treatments to counteract the abnormal end-point of the processes† (Paul R. Buckland, 1769).Therefore, countless researches, studies, and genetic approaches have been ongoing for many years in order to find any association or linkage betwe en genetic factors and drugs addiction. As a matter of fact, many of these researches could come up with great results and very useful conclusions. For instance, Hamid Ghodse stated in his book â€Å"Drugs and Addictive Behaviour: A Guide to treatment† that â€Å"the discovery within the body of endogenous receptor systems for a number of psychoactive substances has revived interest in a link between drug dependency and genetic predisposition† (19).In addition, according to the National Institute on Drug Abuse (NIDA), â€Å"genes that people are born with, in combination with environmental influences, account for about half of their addiction vulnerability. † In the same context and quoting from experts, Abramovitz, Melissa wrote in her article titled â€Å"Addiction† that â€Å"genetic factors that affect how the brain responds to drugs play a big part in pushing people toward drug addiction, and researches have found several genes linked to nicotine, c ocaine, and alcohol addiction. Also, Mayo Foundation for Medical Education and Research (MFMER) reported that â€Å"once a person has started using a drug, the development into addiction may be influenced by inherited traits. † Therefore, most of researchers confirm the idea that genetic factors play a crucial rule in the process of addiction. However, Paul R. Buckland came up with so many important results, which are in fact a little bit different from the ones stated above, by reviewing and evaluating almost all the studies and evidence that claim the existence of genetic factors in the process of addiction.So, he found that â€Å"the phenotype for addiction to drugs is not well defined, and the heritability of addiction to drugs of abuse is far from clear and may be small compared to that of many other complex disorders† (1773). Moreover, he concluded saying that â€Å"many candidate genes put forward so far as susceptibility genes may be unrelated to the underlyin g process referred to as addiction but, rather, are related to the propensity to take drugs in the first place† (1769, 1770). But, that does not mean that there is no association between genetic factors and addiction process.In fact, Paul R. Buckland himself has confirmed that there are some genetic studies that have reported a great number of success and could ultimately find some linkage between genes and addiction, but he ended highlighting â€Å"the need for even larger samples and new statistical methods or new experimental approaches to identify fully the genes involved in the disease process† (1771, 1772). Of course, genetic factors are not the only cause behind drug addiction; no one can become addicted to drugs if s/he has never started using drugs.Accordingly, there may be other factors that affect the predisposition to drugs abuse. Actually, a person’s environment includes many different influences that seem to play a significant role in initial drug u se. At the first glance, it may spring to many people’s minds that local social problems such as poverty, ignorance, unemployment, break-up of local communities, drug pushers are the main causes of drugs addiction, but according to Hamid Ghodse â€Å"these often-repeated phrases may well be contributory factors,†¦but they are not the causes of drug dependence† (11).On the other hand, the National Institute on Drug Abuse (NIDA) and the Mayo Foundation for Medical Education and Research (MFMER) both consider environmental factors, including one’s family’s beliefs and attitudes, exposure to a peer group that encourages drug use, the socioeconomic status and quality of life in general, as the most important influencers that shape addictive behaviour.In fact, Hamid Ghodse, also, illustrates these factors clearly by showing us how â€Å"peer networks can provide opportunities for drug use and support this behaviour† (16) and how â€Å"the importanc e of peer networks reflect the support or lack of support that the child is receiving at home and the importance of the parent-child relationship as a protective factor against the use of drugs† (16).Therefore, he gives us some situations in which family may play a significant role in the initiation of drug abuse: Factors such as family disruption, criminality and drug abuse of parents and siblings have all been identified as important predisposing factors for drug abuse later on, as have inadequate or ineffective parental supervision and enforcement of rules†¦while satisfactory family relationships and climate, and emotional support to adolescents are influences that appear to delay or diminish initiation into drug use, they can only be developed over a long period of time and attempts to make up for their absence by measures such as a sharp increase in parental control of the adolescent’s behaviour may lead to increased rather than diminished drug abuse (16). In addition to genetic and environmental factors, the age or the stage at which a person starts consuming drugs may have a considerable impact on the process of becoming drugs addicted. According to the National Institute on Drug Abuse (NIDA), â€Å"Although taking drugs at any age can lead to addiction, the earlier that drug use begins, the more likely it is to progress to more serious abuse. For instance, one study concerning alcohol addiction which is almost the same as the case of drug addiction showed that â€Å"teens who begin drinking alcohol with their friends before age 15 are four times likelier to become alcoholic than are people who wait until age 21 to drink† (National Institute on Drug Abuse (NIDA), quoted in Abramovitz, Melissa). In the same context, Hamid Ghodse said that â€Å"adolescent drug abuse is of particular importance not only because of the potential for drug-induced harm in a young person but also because taking drugs in childhood and adolescence is a strong predictor for drug abuse in adulthood† (17). Moreover, observations as such, he said, â€Å"have led to theories that suggest that using one drug leads on the consumption of more dangerous drugs with a higher dependence liability† (17).Besides, one other reason that we may discover when seeking causes that are related to the stage of initiating using drugs is prescriptions. According to Hamid Ghodse, most of drug-dependent individuals have personality disorders such as low self-esteem and confidence, high anxiety, low assertiveness, and tendency towards hypochondria, so they begin to take some sedatives and tranquillizers or even drugs as self-medication or as treatment prescribed by a doctor to overcome these problems (15, 17). The problem is that many people become addicted to these treatments by continuing using them as Jeffrey Kluger shows in his article The New Drug Crisis: Addiction by Prescription.According to Kluger many people become addicted to some p rescriptions such as Opioid, Oxycontin, Vicodin, and Hydrocodone while trying to find a treatment to some diseases like cancer pain. In conclusion, it is true that taking drugs for the first time may be a voluntary decision, but factors such us person’s biology, social environment, and age or stage of development undoubtedly play a considerable role in the process of addiction. Genetic factors that affect how the brain responds to drugs and environmental factors, including family’s beliefs and attitudes, peers’ ethics and behaviour, and socioeconomic status, in addition to the culture and the age or the stage at which a person starts using drugs all contribute in shaping addictive behaviour.The problem with drugs is that once a person starts consuming them, s/he may not be able to give up abusing them; hence, we should all be aware that drugs addiction is not just a normal habit that we can stop whenever we want, but rather a complex illness and a serious diseas e that makes the consumer lose self-control and ability to make right decisions. In fact, drugs addiction is a contemporary chronic disease that can cause harmful long-term consequences not only on the user but also on those around him, but as a matter of fact we can prevent ourselves from all these troubles by just avoiding initiating its causes. Works Cited Abramovitz, Melissa. â€Å"Addiction. † Current Health 2; Sep 1999: 26. Print. Buckland, Paul R. â€Å"Will We Ever Find the Genes for Addiction? Addiction, volume 103 number 11, November 2008, pp 1768-1776. Jeffrey, Kluger. â€Å"The New Drug Crisis: Addiction by Prescription†. Time September 13, 2010: p46-49. Print. Ghodse, Hamid. â€Å"Drugs and Addictive Behaviour: A Guide to Treatment. † London: University of Cambridge Press. 2002. Print. Mayo Clinic staff. Drug Addiction, MayoClinic. com, Mayo Foundation for Medical Education and Research, 2009, web. November 2010. (http://www. mayoclinic. com/ healt h/ drug-addiction/DS00183). National Institute on Drug Abuse, Drug Abuse and Addiction, MedicineNet. com, MedicineNet. Inc, 2010, Web. 21 November 2010. (http://www. medicinenet. com/ drug_abuse/article. htm).

The Story of Ferdinand A Childrens Book Review

More than 75 years ago, Munro Leaf wrote The Story of Ferdinand and his friend Robert Lawson illustrated the story. Ferdinand is a bull, who grows up with other young bulls in the pastures of Spain, an unlikely character and setting for a children’s picture book. The story revolves and grows around Ferdinand’s unique, gentle nature compared to the other bulls who like to fight with each other. A little longer text than most picture books, the story can be enjoyed on different levels by children 3 years old and up, as well as older children and adults. More About the Story As time goes by Ferdinand becomes bigger and stronger like all the other bulls hes growing up within the countryside of Spain. But his nature does not change. While the other bulls continue to enjoy butting and sticking each other with their horns, Ferdinand is happiest when he can sit quietly under the cork tree and smell the flowers. Of course, Ferdinand’s mother is concerned that he does not run and play with the other bulls, but she is understanding and wants him to be happy. And happy he is until one day he sits on a bumblebee while five men are visiting to pick the best bull for the bullfights in Madrid. Ferdinand’s reaction to the bee sting is so strong and fierce that the men know they have found the right  bull. The day of the bullfight is incredible, with flying flags, bands playing, and lovely ladies with flowers in their hair. The parade into the bullring includes the Banderilleros, the Picadores, the Matador and then comes the bull. Children love discussing what Ferdinand will do. Enjoyed by a Wide Audience The story of Ferdinand is truly a timeless classic that has been enjoyed worldwide for several generations. Translated into 60 different languages, Ferdinand is a playful and funny story that will have appeal simply for its humor, or for its many messages. Readers will each discover their own piece of wisdom, such as: be true to yourself; the simple things in life give the most pleasure; take time to smell the flowers, and even advice for mothers raising a child with introvert tendencies. Although the black and white illustrations are different from most modern picture books, this is a feature that fits with this peaceful tale. The vocabulary is for an older reader but even three-year-olds can be amused and enjoy the comforting story. Most adults will likely be familiar with The Story of Ferdinand. If not, you won’t want to overlook this one. Illustrator Robert Lawson Robert Lawson received his art training at the New York School of Fine and Applied Arts. His favorite medium, pen, and ink are used expressively and with detail in the black and white illustrations in The Story of Ferdinand. He did not illustrate just to reach a young audience, as shown in the details of the flowers in the ladies’ hair, the clothes of the Banderilleros, and the expressions of the Picadores. Additional readings will bring about humorous discoveries, like the bandages on the bulls and the bunches of cork growing in Ferdinand’s favorite tree. In addition to illustrating many childrens books by others, including Mr. Poppers Penguins, Robert Lawson also wrote and illustrated a number of his own books for children. Lawson had the distinction of winning the two most prestigious awards for childrens literature. He won the 1940 Randolph Caldecott Medal for his picture book illustrations for They Were Strong and Good and the 1944 John Newbery Medal for his book Rabbit Hill, a novel for middle-grade readers. Author Munro Leaf and The Story of Ferdinand Munro Leaf, born in Hamilton, Maryland in 1905, graduated from the University of Maryland and received an MA in English literature from Harvard University. He wrote more than 40 books during his career, but the book that gained the most popularity was about gentle Ferdinand the bull. The Story of Ferdinand was penned on a rainy Sunday afternoon in just 40 minutes for his friend, Robert Lawson, who felt constricted by publishers’ ideas. Leaf wanted to give Lawson a story that he could have fun illustrating. There are those who considered The Story of Ferdinand to have a political agenda since it was published in September of 1936 during the Spanish Civil War. However, it was actually written in October of 1935 and Leaf and his family always denied any political intentions. According to Munro Leaf, it’s a happy-ending story about being yourself.†(Source: School Library Journal) Leaf’s second most popular book, Wee Gillis, was also illustrated by his friend Robert Lawson. Leaf, who died in 1976 at the age of 71, had intended to write a book about how Ferdinand had given him a good life. He was known to say, â€Å"I’m going to call it ‘A Little Bull Goes a Long Way’.†