A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and also to a surface. These adherent cells become embedded within a slimy extracellular matrix, composed of extracellular polymeric substances; the cells within the biofilm produce the EPS components, which are a polymeric conglomeration of extracellular polysaccharides, lipids and DNA. Because they have three-dimensional structure and represent a community lifestyle for microorganisms, they have been metaphorically described as "cities for microbes". Biofilms may form on living or non-living surfaces and can be prevalent in natural and hospital settings; the microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which, by contrast, are single-cells that may float or swim in a liquid medium. Biofilms can form on the teeth of most animals as dental plaque, where they may cause tooth decay and gum disease. Microbes form a biofilm in response to various different factors, which may include cellular recognition of specific or non-specific attachment sites on a surface, nutritional cues, or in some cases, by exposure of planktonic cells to sub-inhibitory concentrations of antibiotics.
A cell that switches to the biofilm mode of growth undergoes a phenotypic shift in behavior in which large suites of genes are differentially regulated. A biofilm may be considered a hydrogel, a complex polymer that contains many times its dry weight in water. Biofilms are not just bacterial slime layers but biological systems. Biofilms can attach to a surface such as a tooth, rock, or surface, may include a single species or a diverse group of microorganisms; the biofilm bacteria can share nutrients and are sheltered from harmful factors in the environment, such as desiccation, a host body's immune system. A biofilm begins to form when a free-swimming bacterium attaches to a surface. Biofilms are hypothesised to have arisen during primitive Earth as a defence mechanism for prokaryotes at that time, as the conditions of primitive Earth were too harsh for the survival of prokaryotes. Biofilms protect prokaryotic cells by providing them homeostasis encouraging the development of complex interactions between the biofilm cells.
The formation of a biofilm begins with the attachment of free-floating microorganisms to a surface. The first colonist bacteria of a biofilm may adhere to the surface by the weak van der Waals forces and hydrophobic effects. If the colonists are not separated from the surface, they can anchor themselves more permanently using cell adhesion structures such as pili. Hydrophobicity can affect the ability of bacteria to form biofilms. Bacteria with increased hydrophobicity have reduced repulsion between the substratum and the bacterium; some bacteria species are not able to attach to a surface on their own due to their limited motility but are instead able to anchor themselves to the matrix or directly to other, earlier bacteria colonists. Non-motile bacteria cannot recognize surfaces or aggregate together as as motile bacteria. During surface colonization bacteria cells are able to communicate using quorum sensing products such as N-acyl homoserine lactone. Once colonization has begun, the biofilm grows by a combination of cell recruitment.
Polysaccharide matrices enclose bacterial biofilms. In addition to the polysaccharides, these matrices may contain material from the surrounding environment, including but not limited to minerals, soil particles, blood components, such as erythrocytes and fibrin; the final stage of biofilm formation is known as dispersion, is the stage in which the biofilm is established and may only change in shape and size. The development of a biofilm may allow for an aggregate cell colony to be resistant to antibiotics. Cell-cell communication or quorum sensing has been shown to be involved in the formation of biofilm in several bacterial species. Biofilms are the product of a microbial developmental process; the process is summarized by five major stages of biofilm development: Initial attachment Irreversible attachment Maturation I Maturation II Dispersion Dispersal of cells from the biofilm colony is an essential stage of the biofilm life cycle. Dispersal enables biofilms to colonize new surfaces. Enzymes that degrade the biofilm extracellular matrix, such as dispersin B and deoxyribonuclease, may contribute to biofilm dispersal.
Enzymes that degrade the biofilm matrix may be useful as anti-biofilm agents. Recent evidence has shown that a fatty acid messenger, cis-2-decenoic acid, is capable of inducing dispersion and inhibiting growth of biofilm colonies. Secreted by Pseudomonas aeruginosa, this compound induces cyclo heteromorphic cells in several species of bacteria and the yeast Candida albicans. Nitric oxide has been shown to trigger the dispersal of biofilms of several bacteria species at sub-toxic concentrations. Nitric oxide has potential as a treatment for patients that suffer from chronic infections caused by biofilms, it is assumed that cells dispersed from biofilms go into the planktonic growth phase. However, recent studies have shown that the physiology of dispersed cells from Pseudomonas aeruginosa biofilms is different from those of planktonic and biofilm cells. Hence, the dispersal process is a unique stage during the transition from biofilm to planktonic lifestyle in bacteria. Dispersed cells are found to be virulent against macrophages and Caenorhabditis elegans, but sensitive towards iron stress, as compared with planktonic cel
The Hours is a 2002 psychological drama film directed by Stephen Daldry and starring Meryl Streep, Nicole Kidman, Julianne Moore. Supporting roles are played by Ed Harris, John C. Reilly, Stephen Dillane, Jeff Daniels, Miranda Richardson, Allison Janney, Toni Collette, Claire Danes, Eileen Atkins; the screenplay by David Hare is based on Michael Cunningham's 1998 Pulitzer Prize-winning novel of the same title. The plot focuses on three women of different generations whose lives are interconnected by the novel Mrs Dalloway by Virginia Woolf; these are Clarissa Vaughan, a New Yorker preparing an award party for her AIDS-stricken long-time friend and poet, Richard in 2001. The film was released in Los Angeles and New York City on Christmas Day 2002, was given a limited release in the United States and Canada two days on December 27, 2002, it did not receive a wide release in North America until January 2003, was released in British cinemas on Valentine's Day that year. Critical reaction to the film was positive, with nine Academy Award nominations for The Hours including Best Picture, a win for Nicole Kidman for Best Actress.
With the exception of the opening and final scenes, which depict the 1941 suicide by drowning of Virginia Woolf in the River Ouse, the action takes place within the span of a single day in three different decades and alternates between them throughout the film. In 1923, Virginia has begun writing the book Mrs Dalloway in her home in the town of Richmond outside London. In 1951, troubled Los Angeles housewife Laura Brown escapes from her conventional life by reading Mrs Dalloway. In 2001, New Yorker Clarissa Vaughan is the embodiment of the novel's title character, as she spends the day preparing for a party she is hosting in honor of her former lover and friend Richard, a poet and author living with AIDS, to receive a major literary award. Richard tells Clarissa that he has stayed alive for her sake and that the award is meaningless because he didn't get it sooner, until he was on the brink of death, she tells him. Richard refers to Clarissa as "Mrs. Dalloway" – her namesake – because she distracts herself from her own life the way that the Woolf character does.
Each story in chronological order, not the order as presented in the movie: 1923 -- Virginia, who has experienced several nervous breakdowns and suffers from depression and bipolar disorder, feels trapped in her home. She is intimidated by servants and under the eye of her husband, who has begun a publishing business at home, Hogarth Press, to stay close to her. Virginia both dreads an afternoon visit from her sister Vanessa and her children. Virginia passionately kisses her sister on the lips. After their departure, Virginia flees to the railway station, where she is awaiting a train to central London, when Leonard arrives to bring her home, he tells her. She says she fears it but argues that if she is to live, she has the right to decide how and where. 1951 -- Pregnant with her second child, Laura spends her days in her tract home with her young son, Richie. She married her husband, soon after World War II. On the surface they are living the American Dream, but she is nonetheless unhappy, she and Richie make a cake for Dan's birthday.
Her neighbor Kitty drops in to ask her if she can feed her dog while she's in the hospital for a procedure. Kitty reveals that the procedure is related to the fact that she has been unable to conceive, may portend permanent infertility, that she feels that a woman is not complete until she is a mother. Kitty pretends to be upbeat, but Laura senses her sadness and fear and boldly kisses her on the lips. Laura and Richie make another cake and clean up, she takes Richie to stay with a babysitter, Mrs. Latch. Richie runs after his mother. Laura checks into a hotel. Laura begins to read it, she dreams the hotel room is flooded. She caresses her belly, she picks up Richie, who fearfully tells his mother he loves her, they return home to celebrate Dan's birthday. 2001 -- Clarissa appears worried about Richard's depression and the party she is planning for him. Clarissa, bisexual and has been living with Sally Lester for 10 years, had been in a relationship with Richard during their college days, she meets with Richard's ex-lover Louis Waters.
Clarissa's daughter, comes home to help her prepare. Richard has taken a combination of Xanax and Ritalin and tells Clarissa that she is the most beautiful thing that he had in life, before he commits suicide in front of her; that night, Richard's mother, arrives at Clarissa's apartment. It is clear that Laura's eventual abandonment of her family was traumatic for Richard, but Laura reveals that it was a better decision for her to leave the family after the birth of her daughter than to commit suicide, she has led an happier life as a librarian in Canada. She does not apologize for the hurt that she caused to her family and suggests that it's not possibl
Experiments involving non-human primates include toxicity testing for medical and non-medical substances. Around 65,000 NHPs are used every year in the United States, around 7,000 across the European Union. Most are purpose-bred, their use is controversial. According to the Nuffield Council on Bioethics, NHPs are used because their brains share structural and functional features with human brains, but "while this similarity has scientific advantages, it poses some difficult ethical problems, because of an increased likelihood that primates experience pain and suffering in ways that are similar to humans." Some of the most publicized attacks on animal research facilities by animal rights groups have occurred because of primate research. Some primate researchers have abandoned their studies because of attacks. In December 2006, an inquiry chaired by Sir David Weatherall, emeritus professor of medicine at Oxford University, concluded that there is a "strong scientific and moral case" for using primates in some research.
The British Union for the Abolition of Vivisection argues that the Weatherall report failed to address "the welfare needs and moral case for subjecting these sensitive, intelligent creatures to a lifetime of suffering in UK labs". Human beings are recognized as persons and protected in law by the United Nations Universal Declaration of Human Rights and by all governments to varying degrees. Non-human primates are not classified as persons in most jurisdictions, which means their individual interests have no formal recognition or protection; the status of non-human primates has generated much debate through the Great Ape Project, which argues that great apes should be given limited legal status and the protection of three basic interests: the right to live, the protection of individual liberty, the prohibition of torture. In 1997, the United Kingdom announced a policy of no longer granting licenses for research involving great apes, the first measure to ban primate use in research. Announcing the UK’s ban, the British Home Secretary said: "his is a matter of morality.
The cognitive and behavioural characteristics and qualities of these animals mean it is unethical to treat them as expendable for research." Britain continues to use other primates in laboratories, such as marmosets. In 2006 the permanency of the UK ban was questioned by Colin Blakemore, head of the Medical Research Council. Blakemore, while stressing he saw no "immediate need" to lift the ban, argued "that under certain circumstances, such as the emergence of a lethal pandemic virus that only affected the great apes, including man experiments on chimps, orang-utans and gorillas may become necessary." The British Union for the Abolition of Vivisection described Blakemore's stance as "backward-looking." In 1999, New Zealand was the first country to ban experimentation on great apes by law. On June 25, 2008, Spain became the first country to announce that it will extend rights to the great apes in accordance with GAP's proposals. An all-party parliamentary group advised the government to write legislation giving chimpanzees, bonobos and orangutans the right to life, to liberty, the right not to be used in experiments.
The New York Times reported that the legislation will make it illegal to kill apes, except in self-defense. Torture, which will include medical experiments, will be not allowed, as will arbitrary imprisonment, such as for circuses or films. An increasing number of other governments are enacting bans; as of 2006, New Zealand, the Netherlands and the United Kingdom had introduced either de jure or de facto bans. The ban in Sweden does not extend to non-invasive behavioral studies, graduate work on great ape cognition in Sweden continues to be carried out on zoo gorillas, supplemented by studies of chimpanzees held in the U. S. Sweden's legislation bans invasive experiments on gibbons. In December 2005, Austria outlawed experiments on any apes, unless it is conducted in the interests of the individual animal. In 2002, Belgium announced that it was working toward a ban on all primate use, in the UK, 103 MPs signed an Early Day Motion calling for an end to primate experiments, arguing that they cause suffering and are unreliable.
No licenses for research on great apes have been issued in the UK since 1998. The Boyd Group, a British group comprising animal researchers, philosophers and animal advocates, has recommended a global prohibition on the use of great apes; the use of non-human primates in the EU is regulated under the Directive 2010/63/EU. The directive took effect on January 1, 2013; the directive permits the use of non-human primates. Testing on non-human primates is permitted for basic and applied research and safety testing of drugs and other products and research aimed on the preservation of the species; the use of great apes is not permitted, unless it is believed that the actions are essential to preserve the species or in relation to an unexpected outbreak of a life-threatening or debilitating clinical condition in human beings. The directive stresses the use of the 3R principle and animal welfare when conducting animal testing on non-human primates. A 2013 amendment to the German Animal Welfare Act, with special regulations for monkeys, resulted in a near total ban on the use of great apes as laboratory animals.
The last time great apes were used in labor