Lysozyme Enzymes: Purification and Assaying

muramidase Enzymes purge and As produceingAbstractThis science laboratory investigates the katharsis and hinderanceing of muramidase knowledge sizing excision chromatography and Bradford protein as theorise. genus Micrococcus Lysodeikticus is utilize in this lab as the substratum for muramidase and its enzymatic activities ar find under various pH and substrate engrossments for determine the outflank conditions for muramidase occupation. The full(prenominal)est muramidase action mechanism was observed at a substrate preoccupation of 0.4 mg/mL and at an best phosphate modify pH of 7. These optimum conditions were set as received conditions for assaying the purified dissevers for muramidase military action and for the protein assay. A radical of freak washcloth is utilize as the seminal fluid for lysozyme and it is purified using size exclusion chromatography with chromatography column Sephadex G-50 that has a fragmental process range from 1,500 t o 30,000 daltons. Size exclusion chromatography provides refining of lysozyme, provided to the highest degree 64% of its initial end product is lost in the cultivate of purification through the beads. The highest lysozyme activity was observed for segment 12 indicating a geomorphologic mass range of 15,000da-13,500da for lysozyme. The protein assay indicated a monumental density of protein in the neighbouring subdivisions of purified lysozyme, however the exact niggardliness of lysozyme in albumen re main inconclusive.IntroductionLysozyme is a catalytic enzyme that digests bacterial cell contend and is ground in meaningful amounts in fruitcake snow-covereds. Egg sportsman comparable, standardizedwise known as albumen, is the cytoplasm of the unfertilized en cell, which consists of approximately 40 different proteins dissolved in water (Lee-Huang et al. 1999). The main proteins in albumen be ovalbumin, ovotransferrin, ovomucoid, globulins, lysozyme, ovomucin, a vidin, etc (Lee-Huang et al. 1999). Lysozyme comprises about 3.5 % of the do protein metric weightiness unit in albumen (Lee-Huang et al. 1999) and thus a solution of egg white was use as the source of lysozyme in this lab. The main accusing of this lab is to purify lysozyme using size exclusion chromatography for examining its structural properties and concentration in albumen.In this essay lysozyme is extracted and purified from albumen using size exclusion chromatography. The stationary phase in the column consists of a porous cross linked gel matrix of Sephadex G-50 with a pieceation range of 1,500da to 30,000da. Separation and purification by size exclusion chromatography is found on molecular size i.e. larger molecules rinse first with the erratic phase patch the flyspecker molecules get confine wi geld the beads and wash last (Lodish et al. 2000). The different proteins cave in in albumen should elute at different fractions due(p) to their varying molecular si zes leading to the purification of lysozyme which has a literature structural mass of 14,400da. It is hypothesized that since lysozyme is a small molecule in comparison to the fractionation range of the Sehadex G-50 coloumn, a squ be amount of lysozyme is likely to be trapped or retarded by the resin beads dissolvering in a unhopeful yield.Substrate binding is utilise as a powerful effective document in this experiment where the enzymatic answers ar used for detecting the aim of lysozyme. The structural composition of lysozyme consists of 129 amino acid residues f create into a weightlift globular mental synthesis with a cleft for substrate binding (Berg et al. 2002). When a substrate binds to the cleft, it hydrolyzes the peptidogly piece of ass polysaccharide found in many bacterial cell walls, resulting in the osmotic lyses of the cell (Berg et al. 2002). Gram positive bacteria atomic number 18 more susceptible to the acts lysozyme due to their peptidoglycan cell wa ll world unfastened to the extracellular environment (Lee-Huang et al. 1999). However, gigabyte negative bacteria ar less vulnerable to the presence of lysozyme due to their thin layer of peptidoglycan shielded by the outer membrane of lipopolysaccharide (Lee-Huang et al. 1999). In this lab, the thou positive bacteria of Micrococcus Lysodeikticus is used as a substrate for detecting the enzymatic activities of lysozyme. The Bradford assay on the some some other softwood is used to estimate the concentration of lysozyme with respect to other major proteins open in albumen.Lysozyme has great search importance since it possesses the capability to lyse gram positive bacteria. Lysozyme, like near of the other biomolecules be not found in nature in its isolated contrive and this lab investigates peerless of the most simplest orders for extracting and purifying lysozyme from albumen.Materials and MethodsA solution of egg white diluted to with 0.1 M phosphate buffer pH 7 and filtered though glass wool is used as the source for lysozyme (Laboratory Manual. 2007). The solution is put through size exclusion chromatography with G-50 Sephadex column (fractionation range of 1,500-30,000 da) to realise 24 test metros of equal egg white fractionations of 0.75 mL (Laboratory Manual. 2007). many assays are conducted with varying pH and genus Micrococcus (substrate) concentration to determine the optimal conditions for the highest enzymatic activity of lysozyme. After the collected column fractions and prepared egg white solution were left in the lab for two weeks, the homophile(a) numbered test tubes were assayed for lysozyme activity and the even numbered test tubes were assayed for protein at optimal pH.Refer to York University department of Biology Laboratory Manual Summer 2008, SC/Biol 2020 Cell Biology and Biochemistry P bestrides 54-57 for a more detai lead procedure of the lab. withal refer to the attached f menial sheets for a thorough step by ste p procedure for this lab.ResultsThe addition of genus Micrococcus to a solution of lysozyme results in the rapid diminution in its ocular density nurse due to its enzymatic reactions. Various assays are conducted in this lab to seek various properties of lysozyme. The substrate concentration assay indicated 0.4 mg/mL of micrococcus to be the optimal substrate concentration for lysozyme as it resulted in the highest enzymatic activity of 250 units. The pH assay on the other hand indicated pH 7 to be the ideal pH for the phosphate buffer as it resulted in the high lysozyme activity of 300 units. These observations led us to set 0.4 mg/mL micrococcus and buffer pH of 7 as stock(a) conditions for assaying the size exclusion column fractionations for protein activity. When assaying the extraordinary numbered fractionations for lysozyme activity, fraction 15 reached the highest enzymatic activity of 900 units specifying the presence of tough lysozyme in that fraction of egg white. The neighbouring fractions (14 and 16) showed signifi hawk protein concentrations of 4.4 mg/mL and 1.6 mg/mL when assayed however the highest protein concentration as observed in fraction 12 which indicated a protein concentration distant the standard curve range. Upon dilution, the protein concentration of fraction 12 was calculated to be 9mg/mL. establish on the results, a protein f gray of 1.36 was calculated and the results showed a high lysozyme yield prejudice of about 64%.CalculationsSample computation of Micrococcus dilutionTarget 3 ml of 0.4 mg/ml MicrococcusC1V1 = C2V2(10 mg/ml)(x ml) = (0.4 mg/ml)(3 ml)X = 0.12 ml of Micrococcus3 ml 0.12 ml = 2.88 ml so, 0.12 ml of Micrococcus and 2.88 ml of Phosphate buffer go out be filldSample calculation of total protein in fraction 15protein concentration of 0.52 mg/mLVolume in fraction 0.1 mLTotal protein = 0.52mg/mL X 0.1mL = 0.052 mgSample calculation of Total Enzyme use in fraction 15 progressiveness = OD x 1min/0.00 1 exercise = (0.4) x 1min/0.001Activity = 400 unitsSample calculation of Specific Activity for fraction 15Enzyme activity of column fraction 15 = 90 unitsTotal protein = 0.052 mgSpecific Activity = Enzyme Activity/Total proteinSpecific Activity = 400 units/( 0.052 mg)Specific Activity = 7692 units/mg proteinSample calculation of initial precise activity of the egg white at 0.3 mg/ml substrateSpecific Activity = Enzyme Activity/Total ProteinSpecific Activity = 90 units/(4.5 mg/ml x 0.1 ml)Specific Activity = 200 units/ mg proteinCalculation of Fold refiningFold Purification = Specific Activity of fraction/Specific Activity of egg whiteFold Purification = (7692 units/ mg protein) / (200 units/ mg protein) = 38.46 newsThis lab experiment examines the purification and assaying of egg white lysozyme. Lysozyme is some(prenominal) a protein and an enzyme that catalyzes the hydrolysis of 1,4-beta-link get alongs betwixt N-acetylmuramic acid and N-acetyl-D-glucosamine residues in pepti doglycan (Lodish et al. 2000). It is found in verdant quantities in albumen (egg whites) where it entertains the egg embryo from bacterial invasion. Several assays were conducted in this lab experiment and each assay evidenced a significant property of lysozyme.Enzymes take in optimal conditions at which it divisions most stiffly and it is all Copernican(p) that enzymes are studied under optimal conditions for the most accurate results and observations. The substrate concentration assay and pH assay were employed in this experiment to determine the optimal conditions for lysozyme since its enzymatic activity varies with substrate concentration and buffer pH. Appropriate substrate concentration is significant for an enzymatic reaction because a high substrate concentration might outnumber the lendable active sites on lysozyme while a low substrate concentration volition repudiate vacant binding sites on the lysozyme. This lab proved 0.4 mg/mL of Micrococcus to be the optim al substrate concentration for lysozyme with a high enzymatic activity of 250 units. The mark of the optimal pH at which the substrate-enzyme binding is carried out most expeditiously is some other important aspect of an enzymatic reaction. An environment too sulfurous or basic could cause hindrance for the substrate-enzyme binding and thus result in low lysozyme activity. The phosphate buffer pH assay in this lab proved pH 7 to be the optimal pH at which the enzymatic activities of lysozyme are carried out most efficiently with an enzymatic activity of 300 units.Size exclusion chromatography is used in this experiment for extracting and purifying lysozyme from the mixture of approximately 40 proteins that is present in albumen. Other proteins that are present in significant quantities in egg whites are ovalbumin (66 kDa), ovotransferrin (77.8 kDa), ovomucoid (28 kDa), ovomucin, avidin (18kDa), etc. however no(prenominal) of these proteins share the same molecular mass as lysozy me which has a literature molecular weight of 14.5 kDa (Lee-Huang et al. 1999). This unparalleled mass distinction mingled with the proteins present in albumen allows size exclusion chromatography to be an effective method in purifying lysozyme as its separation method is solely establish on molecular mass difference.Specific natural selection of resin for the column is another(prenominal) important factor in protein purification as the porosity and fractionation range of the column should be focused on the protein creation purified. This experiment uses the Sephadex G-50 column for protein purification. The stationary phase of Sephadex G-50, has a bead matrix with a well defined pore size for separating proteins within the fractionation range of 1,500da 30,000da. Sephadex G-50 is well suited for lysozyme purification because lysozyme has a literature molecular mass of 14,400da (Lee-Huang et al. 1999) which falls central between the column fractionation range.Purification of lysozyme however would be with the cost of obtaining low lysozyme yields. During purification, the larger molecules elute first while the smaller molecules like lysozyme travel through the beads and elute last. This disturbs the yield of lysozyme as some of its initial mass gets trapped within the gel matrix beads during separation while another small fraction of the initial yield is lost due to the deliberateness of the lysozyme during the in and out diffusion of the protein from the beads in the matrix (Laboratory Manual. 2007). Thus for a method like size exclusion chromatography, I would predict genuinely low yields. The prediction was proved to be true(a) as the data collected from the experiment demonstrated a low yield of 36%. Thus even though the method of size exclusion chromatography is effective in purifying lysozyme, it comes with the disadvant age of low yield.Micrococcus, the substrate for lysozyme in this experiment, is a gram positive bacteria with an unfasten ed peptidoglycan cell wall (Lee-Huang et al. 1999). Like any other enzymes, lysozyme is very specific about its substrate and the ability of lysozyme to bind to micrococcus and lyse the cell allows us to follow its enzymatic activity through the decrease in optical density detected on the spectrometer. Lysozyme activity assay demonstrated a peak for the highest enzymatic activity at fraction 15. The peak represents the single protein species of lysozyme because micrococcus can solo be digested by lysozyme and no other albumen proteins. Therefore all activities observed for lysozyme assay is due to the presence of lysozyme binding and hydrolyzing the peptidoglycan in the cellular walls of micrococcus. Micrococcus is thus the ideal substrate for this experiment however it as well as poses some disadvantages as well due to its biohazardous nature. Micrococcus unavoidably to be handled with extra caution and is to be cast out of appropriately.The lysozyme assay showed the highest specific activity of 900 units in fraction 15. This indicated that fraction 15 guideed purified lysozyme. Considering the fractionation range of 1,500 30,000 da of the chromatography, and the elusion of a dogged volume into 24 separate test tubes, an estimation of the molecular weight range for fraction 15 could be do roughly 15,000 da 13,500 da, a range that covers the literature molecular mass of lysozyme, 14,400 da. Thus, our detection for the fraction of egg white containing purified lysozyme was pretty accurate.The Bradford protein assay was used in this lab to examine the protein concentration of lysozyme with reference to the other proteins present in albumen. Theoretically lysozyme comprises about 3.5% of the total protein mass in albumen (Canado et al. 2007). Even though it is a significant amount, thither are other proteins comprising a higher concentration in albumen. The eccentric fractionations closest to 15 show fair concentrations of protein with 14 displa y a concentration of 4.4 mg/mL and 15 showing 1.6 mg/mL. In order to get an accurate reading for the lysozyme protein concentration, fraction 15 would view as to be directly assayed instead of its neighbouring fractions. Thus the actual lyoszyme concentration in albumen remains inconclusive. The highest protein peak was observed for fraction 12 with a protein concentration that went beyond the standard curve range. Upon dilution, the protein concentration of 12 was determined to be approximately 9 mg/mL. This indicates that a protein that eluted in fraction 12 is the most concentrated in albumen.Specific activity is defined as the enzyme activity over total amount of protein (Laboratory Manual. 2007). The specific activity of 900 units/mg protein for fraction 15 and the specific activity of the initial egg white solution of 666.66 a fold purification of 1.35(Refer to calculations). The yield of lysozyme after purification was fairly low indicating a high percent of loss. This loss was due to a portion of lysozyme world trapped within the beads of the matrix during purification and another small portion being distorted during in and out diffusion of lysozyme (Laboratory Manual. 2007). The 64% loss in enzyme yield was worth the increase in purity because purifying the enzyme enabled us to estimate its structural mass and protein concentration in albumen.Sources of error in this lab were tried to be unplowed at its minimal level however there could still be some errors that might grant deviated the results slightly. Lysozyme activity was measured by detecting the difference in optical density on a spectrophotometer in a time period of 1 minute. Incorrect readings of the optical density caused by fingerprints/other residue on the test tube surface or reading the incorrect absorbance at an earlier or later time period could have been a major source of error as this lab is dependent on the accuracy of the optical density readings. Other sources of error coul d be dilution errors as some of the dilution require very minute amounts and pipetting the small amounts with the pipette provided for this lab accurately is very challenging.fresh researches in the field of biochemistry servicing expand our knowledge about cell and molecular processes and thus research interest in the ridiculous enzyme of lysozyme is of no exception. It was previously believed that lysozyme was used primarily as a constitutive defense against bacterial agencyogens tho recent research indicate that in certain species in the animal kingdom the structure of lysozyme is different and the structural difference enables lysozyme to incorporate other useful functions much(prenominal) as digesting bacteria for nutrition (Canado, et al., 2007). Research has as well shed light on urinary lysozyme C showing that a combination of urinary lysozyme C with certain RNases can be used to combat HIV-1 (Lodish et al. 2000). Other researches on lysozyme conducted by Lee-Huang et al. found that lysozyme from chicken egg white, compassionate milk and human neutrophils combined with RNase A from bovine pancreas display activity against HIV-1 (Lee-Huang, et al., 1999). These are significant discoveries that not only broaden our knowledge in biochemistry except also define possible cures for HIV in the future.ConclusionLysozyme is a considerablely distributed enzyme in the animal kingdom that lyse bacterial cells to protect organisms from bacterial invasion and this lab demonstrated some of the important characteristics of this unique enzyme. Micrococcus proved to be an ideal substrate for observing lysozyme activity due to its gram positive nature illustrated by its exposed peptidoglycan cell wall, the cleavage target of lysozyme. The substrate concentration assay and pH assay demonstrated how lysozyme is at its peak enzymatic activity at the optimal substrate concentration of 0.4 mg/mL and at a buffer pH of 7. Even though the exact protein concentration of lysozyme in albumen remains inconclusive, the neighbouring fractions assayed for protein concentration provided an estimate that lysozyme is present in significant amounts in egg white in comparison to the other albumen proteins. Even though lysozyme was successfully purified using size exclusion chromatography with Sephadex G-50 column, its purification resulted in the loss of lysozyme yield. The column beads trapped and retarded about 64% of the total lysozyme resulting in low yields.Overall this was lab was well engineered to demonstrate how size exclusion chromatography can be used for purification ground on molecular mass and how the unique activities of a certain enzyme with its specific substrate can be used to determine the purified fraction that contain the certain enzyme. ask of the Elderly A Case StudyNeeds of the Elderly A Case StudyIntroductionWe live in an maturation world and Australia is not an exception. In 1901 only 4% of Australians were 65 and fourth-year, by 2016 that figure increased to 15.3% and is estimated to rise to 23% by 2041 (Australian power of Statistics, 2016, Australian piece Rights Commission (AHRC), 2012). The United Nations (UN) principles of ageing, supported by the Australian Government, recognises the amends of all of age(p) somebodys, focusing in areas such as freedom participation care self-fulfilment and dignity (Australian Association of well-disposed Workers (AASW), 2013), but are we doing enough to protect these rights and ensuring our aged(a) Australians are not left disfavor? This essay looks at the case of Hank, retrenched from his life-time-timelong employer at the age of 62 with future vocation prospects bleak. It looks at factors through the life course that effect Hank in his sometime(a) categorys and discovers how neighborly Workers can respond to this demographic to assist them in continuing to fulfil a satisfying life. name loving, Psychological and Physical Needs As a complaisant im parter, it is important to have an understanding of the key cordial, psychological and physical needs of the client plus any issues that may be present. In this way, a holistic and specific needs assessment can be do that identifies how a client spotlight affects his needs moving forward (Tanner Harris,2008). Hank was retrenched from his workplace and is having bother purpose a new job. The jobs he is experienced in are becoming unsuitable due to the onset of arthritis and without formal training, his employment prospects are bleak. There have been many studies linking unemployment with lower levels of well-being, and higher levels of distress, self-doubt and dissatisfaction (VanDerMeer,2014). beingness unemployed can be detrimental to ones needs, not only because of lesser income but also due to the effects on psychological and affable factors (VanDerMeer,2014). Societal averages and expectations also plays an important role in well-being, being employed helps us to feel w e are conforming to those values and norms (Thompson,2016, VanDerMeer,2014). Mens fond identity is practicallytimes centred nigh their work and although as a society we are shifting in our view of men being the sole scar winner, for Hanks cohorts, his role as pecuniary provider gave him a sense of gazump and sense of identity. Hanks friends, his affectionate group, have remained at work, this puts added stress on Hanks social welfare, pile who are unemployed are better able to cope when others around them are in the same situation (Clark,2003). piece Rights and LegislationHank, like all Australians, have a universal right to employment regardless of factors such as culture, gender, age and disability (Ife,2012). The Australian Government, through the Australian military personnel Rights Commission, has agreed to uphold the UN covenants on human rights. Although there is no international covenant in the area of ageing, the Universal Declaration Of Human Rights (1948, art. 23) and the International Covenant On Economic, neighborly And ethnic Rights (1966, p.3,art.6) states that everyone has the right to work and be paid without discrimination, and that protections should be in place against unemployment. federal clear upicial ordinance in place to uphold Australian Human Rights include the Australian Human Rights Commission Act 1986 and ripen Discrimination Act 1992. In Victoria, proletarians rights are protected through the make up Opportunity Act 2010, which includes Age and Disability. Adhering to such rights gives all great deal a sense of human dignity, a value held by the Australian Association of Social Workers (AASW) in its statute of ethics (2010). These protections should be an advantage to Hank but unfortunately, in reality age discrimination, modernisation and globalisation often train it difficult to apply. Impact of geomorphologic and historical FactorsAlthough ageing happens to us all regardless of race, culture, gender or cl ass, these structural factors, economic and social policies, plus experiences throughout the life course, often have a significant influence on later life (Hughes Heycox,2010). That influence, restrained by economic and social policies, has the ability to limit choices and opportunities that violation on ageing (Bengtson DeLiema,2016). Australias increasing tribe and its effect on the dependence ratio (the portion of population who are too young or old to work by those of works age), give also have an impact on factors such as housing, medicare, Centrelink, hideaway award and age care.If Hank turns 63 in 2017, he was born in 1954, the rape boom generation. The year of birth is not only important in determining Hanks generational cohorts and possible life course experiences, but also in determining his eligibility for services such as the aged pension and superannuation release. The baby boomers were so called due to the raise in babies born during and post world-war II 194 3 -1964 (Tolbize,2008). According to Tolbize (2008, p.2), it was an era of prosperity and optimism and bolstered by the sense that they are a special generation capable of changing the world, have equated work with self-worth, plowshare and personal fulfillment. Generalising on the typical situation of this generation, Hank and his cohorts would have had a backbreaking sense of work and sacrifice. They believed in loyalty to one employer with success being gained through step-by-step promotion, of paying their dues (Tolbize,2008). Hank was born in the pre-globalisation era where citizenry could more easily get a job without the need for a university or formal trade education (Phillipson,2009). Hank chose to follow the path of his father, leave school at 16 and start work as a machine operator. He expected, just as his father did, to be in his job for the rest of his working life. However, the recent globalisation of the Australian parsimony and technological advances, are often reflected in retrenchment of lower adroit workers like Hank and the creation of structural unemployment where unemployment results from shifts in the economy and by factors such as technological advances, making lower-skilled jobs obsolete (Business Council of Australia (BCA),2004, Klehe et.al,2012). Government measures are ordinarily in place to provide assistance in the form of retrain in such situations. For example, when industries such as the car manufacturing, the government purposed other needed industries for retraining such as, ironically, aged care. For older workers, such as Hank, the offer is often refused. Hanks self-devaluing attitude based on the ageist stereotype of you cant teach an old dog new tricks is often a barricade to flip-flops in ones employment sector.Based on his year of birth, Hank will be eligible for the aged pension at age 66. Since April 1909, when Australia commenced the Invalid and experient Age Pensions Act 1908 for pack aged 65, Australia s retirement, pension and superannuation policies have compose an important factor in the ageing experience. Since then, Australia has made switch overs to abet Australians to be more self-sufficient in their retirement, whence removing the burden of financial assistance from the government. 1915, saw the Income Tax Assessment Act 1915 allowing employers to make contributions on behalf of its employees for superannuation. In 1972 only 32% of Australians where covered by superannuation. In the 80s, the Federal government established policies around superannuation and taxation, this, plus the introduction of superannuation contribution by employers, increased the number of employees covered by retirement fund in 1990 to 64%. In 1992 the superannuation guarantee was implemented, employers were required to establish to their employees superannuation fund. The amount of contribution progressively increased from 3% to 9% in 2002. In July 2017, the qualifying age for the age pension will increase by 6months every two long time until it reaches 67 years of age in 2024 (Parliament of Australia,2010). The impact of government policy in Hanks situation agent, that although he will not be eligible for the aged pension until 66, he is eligible to access his superannuation (Australian Department of Human function (DHS),2017). The Department of Human Services through Centrelink is responsible for income support such as newstart, however in Hanks case, it is unclear if he is eligible for newstart based on his wifes regular income. Victorian Skills Gateway, which is part of the Victorian Government Department Education and Training (DET) offices help with retraining and job search (DET,2017). crafty the importance of older workers in the workforce, the government restart program offers incentives for employers to utilize people over 50 (DET,2017). They are also looking at reforming structural barriers such as workers compensation, income protection and professional l icensing all factors that affect employability of older workers. This is with the hope, that by removing these barriers, will remove negative perceptions of employing older workers (AHRC,2012).Theories of maturementIn the last few decades there has seen the development of many theories on ageing that allow us a better understanding of an older persons world. As a social worker, we can draw upon theories to gain pellucidness in understanding aspects of the human condition (Tanner Harris,2008, Hughes Heycox,2010). Theory can also enable us to find appropriate approaches to dealing with clients based on their specific needs and situations (Tanner Harris,2008).One of the pioneer theories on ageing, which draw popularity in the 60s through to the mid-seventies is breakup theory. Disengagement theory, as proposed by e. e. cummings and Henry (1961) states that ageing involves the gradual and inevitable withdrawal of a person from interacting with society. It supposes that this inev itable withdrawal is mutually beneficial, as it sees the transfer of power from the old members of society to the young. According to this theory, to successfully age means a crash in activity levels and interactions until all activities cease in preparation for remainder (Hughes Heycox,2010). This enables the young a greater opportunity to become more active in contributing to society, thereby keeping society in counterbalance (Victor,2005). Although Hank did not voluntarily leave the workforce, according to this theory, his retrenchment has set off his path to separation. We see this through his discouragement with not finding another job and therefore dropping out of the job search and separate himself from his friends. Proponents of this theory, would see this as natural progression for Hank Hank is on natural course leading to the remainder of his life. The problem with this theory in its original form however, is that it doesnt consider social processes and structures t hat are in place, that may hinder a person such as Hanks ability to engage (Hall Scragg,2012). Critics of this theory say it feeds into the negative stereotypes of ageing, making it seem acceptable and normal for older people to disengage and therefore preventing them from creating circumstances that increase engagement and quality of life (Bengtson DeLiema, 2016). One of its strengths however, is that the development of this theory opened the door to further research, resulting in a clearer view of natural ageing (Bengtson DeLiema,2016). Havighursts (1963) activity theory and Atchleys (1989) persistence theory were both in response to disengagement theory (Carstensen,1991). other such modification to disengagement theory was by Streib Schneider (1971), who concluded that disengagement from one sphere of life, does not mean withdrawal from all spheres (Streib Schneider,1971), this made available the idea of new social roles for the aged. As a social worker, applying Streibs ve rsion of disengagement activity within disengagement to the case of Hank, Streib furiousness the need for a new role for the retrenched, involving activities that are not untainted busy work but should satisfy the social-psychological needs of Hank and be recognise as valid and socially useful pursuits (Streib Schneider,1971). Encouraging Hanks involvement in activities such as the mens shed or volunteer organisations such as meals on wheels or hands on learning (teaching disengaged youths practical skills). These activities evidence themselves from hobby work because they not only benefit Hank but are also of community benefit. Keeping active in such a way may also lead to renewed encouragement towards employment in other areas.Another challenge to the disengagement perspective is the put back theory of ageing. This theory draws upon previous works on the social-psychological theory of exchange, and addresses how a decrease in a persons power and status is associated with ag eing (Dowd,1975). Dowd presents ageing and social interaction in the image of a cost-benefit model. Dowd reasons that as we age our conduct becomes a burden to ongoing interactions with others. It takes a greater military campaign to affirm a level of competent contribution, this decreasing competence means those we interact with are getting less benefit in the think they give. The greater the older person is dependent on others, the more they become a burden. Therefore, an older person begins to withdrawal from social life in order to balance the equation of exchange (Lynott Lynott,1996, Bengtson et.al,1997). For Hank, the loss of his job has minded(p) him a perceived loss of identity, status and power, not only amongst his social circle as Hanks close friends are still employed, but also within his family. Hank took pride in being the financial support conferrer for the family but this has been taken away from him, and his wife Jane has had to step up into full-time work. Ha nk feels he has nothing to offer the workforce or his social circles and therefore has begun to disengage. He is no longer applying for jobs and has withdrawn from contact with people outside his immediate family. The strength of this theory is its power of definition into the descent between the costs and rewards within a relationship. It helps us to understand that when we give something to a relationship whether that be employment, friendship, marriage, that to maintain that relationship, we expect something in return (Bengtson et.al,1997). For Hank, this explains his scent of discouragement, he wants to give but does not feel he has anything to total to a work relationship due to his lack of education and decline in physical health this is also affecting his social network, and family relationship, as he is no longer contributing to the finances. Although this theory is good at explaining relationships on a cost/benefit model, it does not take into card the complexity of relationships and a persons ability to compromise and adapt. It places people in a selfish light willing to give up a relationship if the costs outweigh the benefits. It also doesnt take into account cultural aspects of a relationship and reciprocity of past care or the increased function of older persons assisting the young such as childcare of a grandchild (Poole,2013, Carstensen,1991).Where disengagement theory sees the withdrawal and social isolation of older people as a societal need and of mutual consent, the exchange theory of ageing shows an unequal exchange between older persons and others in society. Disengagement theorists would say the reduction in interaction is fuelled by emotional distancing, whereas exchange looks at the change in dynamics of relationships and interaction (Carstensen,1991). And whilst both theories offer an explanation as to why we decrease in social interaction as we age, both are criticised for their lack of complete empirical data (Carstensen,19 91). For Hank, I can see both as factors for his discouragement and disengagement the change in dynamics due to long term job loss has become a trigger for emotional distancing. For a social worker it is important to draw on the knowledge these and other theories gives us in offering a wider understanding of Hanks circumstance, to assist him in moving forward.Challenges and Social Worker ResponseAt 62, Hank hasnt reached what most of us would consider older age, but he is now facing a serious variety point due to the current circumstance of his job loss. Hank is looking forward at the challenges all Australians face when growing old. Australian society has made significant achievements in the promotion of health and wellbeing of its older citizens. However, our older population still faces many challenges. Some of which include biological and psychological changes general and mental health including dementia care. Other challenges include ageism and social isolation. Ageism can be seen here in discriminatory practices in employment or retrenchment strategies that see people like Hank lose their job or have difficulty in finding new employment (Thompson,2016). Throughout the last century, the Australian government has developed policies, such as those mentioned in previous sections, to enable people to be more self-sufficient in their older years. However, the government focus is often on the cost burden of aged care without consideration of defend human rights, recognising contributions of older Australians and ensuring the needs of social inclusion (Ife,2012, Poole,2013). Although older people may be seen as a burden to society, they actually make substantial contribution. They volunteer an average 4.4hr more a week than working people and are often a valuable source of child-care to their grand-children (Poole,2013).Social work can play an important role in responding to the needs of a client such as Hank by taking a holistic approach to practice. Holi stic care means focusing on the whole person, physical, emotional and spiritual, as it relates to their environment. It is taking into consideration a wide range of factors that affect the client (Tanner Harris, 2008). A social worker will consider all aspects involved in their care including, ecological and systems perspectives, legal and ethical matters, plus the biopsychosocial aspects (AASW,2013). The quality of a persons life can be enriched by adding opportunities to thrive under any circumstances. So assisting Hank maintain his independence and to participate to the fullness of his being, is important to his wellbeing and speaks of Hank in terms of his right to dignity and self-fulfilment. As we have seen above,a social worker uses knowledge, theoretical frameworks and models to identifying the best way to approach and discover the clients, strengths, weakness, and opportunities for participation and well-being. It is also important in the case of Hank, to be up-to-date wit h the latest policies and procedures provided by both deposit and Federal government. A person-centred approach considers the client as the expert in their own life and able to decide on their own lives path (Tanner Harris, 2008). Thus, encouraging clients within the system to take control and be empower within their own lives. The effectiveness of this in Hanks case, is it supports the need for collaboration and keeps at the forefront the client and his family, as people with needs and desires, who should always be in control of their own decisions.Social workers also focus on social justice, delving into the inequalities and oppression within society based on such factors as age, gender, class, poverty, race, culture and sexual orientation to become an advocate of change (AASW,2013, Thompson,2016). They can help develop those opportunities through change in policy, social planning and community involvement (Hughes Heycox,2010). This Contributes not only to the individual clien t, but to the community as a whole.ConclusionWith Australias growing older population and the fast-paced technological world of modernisation and globalisation, there are many real cases like Hanks happening every day. It is hoped that any new federal government reforms will assist in helping older Australians maintain active and productive lives, not only for the sake of individual wellbeing but also for the betterment of society. Social workers can have a role to play in policy reform by being strong voice in advocacy for change. 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