Mechanisms Of Conservative And Replicative Transposition Biology Essay

Mechanisms Of Conservative And Replicative Transposition Biology Essay Bacteriophage Mu is a temperate phage which adopts transposition pathway in its life cycle. Mu has the capability to integrate into numerous sites in host Escherichia coli genome and cause mutations due to its insertional activation. Mu transposes via two major pathways; conservative and replicative transposition though the molecular switch between the two mechanisms remain unknown. This review will focus on the comparisons between replicative and conservative transposition. The first part will discuss the similarities between the two mechanisms; donor DNA cleavage step and strand transfer step which involves nucleophilic attacks, generating single-strand nicks in Mu DNA and joining it to target DNA via one-step transesterification mechanism. The latter part will concentrate on the different characteristics in each transposition mechanism; in replicative transposition, the end product is duplication of transposon copy in both target and host DNA while in conservative transposition, a simple insertion of transposon is produced in the target DNA. 1. Characteristics of bacteriophage Mu Phage, derived from the Greek word phagein, literally means to eat. Bacteriophage Mu was named as such(find out who did) due its nature of infecting and inducing high levels of mutation in host bacteria Escherichia coli., hence the name Mu for mutator. The dual nature of Mu transposon and virus has made it as the archetypal model of studying phage genetics. Bacteriophage Mu is a temperate phage of E. coli which employs the transposition mechanism in its life cycle. Transposition can either be conservative (excising the transposon and inserting it into bacterial chromosome) or replicative (transposon copies are produced in both transposon and bacterial chromosome). Both mechanisms will be discussed extensively later in this article. Unlike the phage ÃŽÂ », insertion of Mu genome into the target site proceeds in a randomly manner which makes it an excellent mutator. Fig. 1: The life cycle of bacteriophage Mu(5). The life cycle of phage Mu is shown schematically in Fig. 1 above. Bacteriophage Mu infect susceptible host cell by adsorption and then, injects its linear viral genome. Once inside the host cell, the linear genome does not circularized(4,5,19), unlike in phage ÃŽÂ ». In either case of lytic or lysogenic phase, Mu integrates its DNA into the host genome via conservative transposition(16,19). This is observed differently in phage ÃŽÂ » where the infecting phage DNA will be integrated into host genome only during lysogenization(19). An enzyme called transposase, encoded by MuA gene in the phage genome, is absolutely crucial to carry out this conservative transposition step. Phage DNA is inserted at multiple sites in a bacterial genome which lead to the assumption that the insertion occur by a random manner(8). However, there are several factors that influence target site selection such as MuA protein efficiency and transposition immunity(15). After integration, Mu usually adopts a quiescent prophage lifestyle(lysogenic phase). The preference between lysogenic and lytic phase in Mu life cycle is dependent on its stability in the lysogen and lysogenic repressors. However, lysogens of Mu phage sometimes enter the lytic phase though this is a rare event. When induced, usually by using temperature-sensitive repressor mutants of phage Mu and subject it at 42ËÅ ¡C, the lysogen will enter lytic cycle. When the lysogenic repressor is inactivated, Mu transposes via replicative transposition, producing copies of phage genome which will be packaged into new virions. The virions then lyse the host cell and infect new hosts. Bacteriophage Mu virions comprised of icosahedral head(diameter 54nm), a baseplate, a contractile tail and six short tail fibres(5). Fig. 2: Simplified cartoon illustrating packaging of Mu genome. Typical length of phage Mu DNA is approximately 37kb long. Additional 2 kb of host DNA is incorporated during DNA packaging which is shown as flanking each end of the integrated Mu genome, with most of it at the right end. Unique sequences of host DNA and at the right end of the packaged DNA is dependent on initiation site of packaging in the host DNA(24). Fig. 3: Physical and genetic map of bacteriophage Mu. Solid black lines represent Mu DNA while the boxes at the two ends indicate flanking host DNA sequences. Mu genes (indicated in block letters) and their corresponding translational products are as indicated(19). A typical size of wild-type phage Mu DNA is about 37.5 kb, however each phage capsid can accommodate up to 39 kb long. Phage genome has a pac site which serves as the starting point in packaging of the phage DNA, located within attL(5). The initiation cleavage by phage enzyme terminase occurs upstream of the phage pac site, which includes host sequence of about 50-150bp flanking the left end. Second cleavage initiated when a complete filling of capsid is achieved, which includes 0.5 kb to 2 kb of host sequence flanking the right end(1). Genetic and physical map of phage Mu is illustrated in Fig. 3. Bacteriophage Mu utilizes headful mechanism strategy, which confer variable lengths of host DNA flanking the left ends of Mu DNA depending on the initiation site of genome packaging(Fig. 2). 2. Transposition mechanism (E) (D) (C) (B) (A) Fig. 4: Modes of bacteriophage Mu transposition. (A), (B) and (C) are the common steps in both conservative and replicative transposition of phage Mu. In conservative and replicative transposition, phage Mu will follow-up step (D) and (E) respectively. Curved arrows indicate nucleophile attack, transferring the 3-OH ends to the staggered 5-phosphate ends of target DNA. Dentate lines (XXXX) indicate target DNA sequences which are duplicated during transposition (16). Numerous in vitro studies have been conducted to study the mechanism of transposition, and usually mini-Mu elements are used. A minimal Mu element consists of a selectable gene, a plasmid replication origin and essential Mu ends(2). The mechanism of transposition is discussed in respect to an in vitro system from this point onwards unless stated otherwise. Following discussion on transposition mechanism are based on Shapiro model(22) as it has been widely accepted as the golden model in this field. The current known modes of transposition is divided into two: non-replicative (conservative) and replicative transposition. Both strategies utilize the same mechanism up to point (Fig. 4C) where each strategy employs different mechanism, producing different end products. A simple insertion of transposon is generated in target DNA by conservative transposition (Fig. 4D) while two copies of transposon formed in both donor and target DNA by replicative transposition (Fig. 4E). Point A to C are considered as the similar features in both conservative and replicative transposition while point D and E is the distinction between the two modes of transposition. Therefore, mechanisms involved in point A,B and C are discussed in context of both replicative and conservative transposition, which comprises of DNA cleavage step and strand transfer step. Sequential stages of both cleavage and strand transfer steps are illustrated in Fig. 4. 2.1 Donor DNA cleavage step Two critical chemical steps in both transposition pathways are donor DNA cleavage step and DNA strand transfer step(5,8). The donor DNA cleavage step is initiated when water molecules within an active site act as nucleophiles, and attack phosphodiester bond in DNA backbone at each of the transposon end(4,5). The cleavage step involves a direct hydrolysis of phosphodiester bond by water, and not by covalent enzyme-DNA intermediate(17). The phosphodiester bond is cleaved at the flanking host-transposon DNA boundary. 3-hydroxyl (OH) ends of the Mu DNA are exposed at the end of the cleavage step. Strand transfer results in fusion of target and donor DNA, which forms an intermediate molecule (8). The process (simplified in Fig. 4C) follows the Shapiro model(22). Bacteriophage-encoded proteins, MuA protein (transposase) and MuB protein (ATPase) are required for transposition. Other requirements to ensure efficiency of transposition are accessory proteins such as host-encoded DNA bending proteins called hydroxyurea (HU) and integration host factor (IHF)(8). The inverted repeats at the end of donor DNA, and target sequence on bacterial chromosome are also important in transposition mechanism. The assembly of higher order protein-DNA complexes called transposome has been identified by in vitro studies(6). A three-site synaptic complex called the LER complex comprising right and left ends of Mu and transpositional enhancer, was formed in the beginning of transposition in vitro(23). MuA protein binds to MuA binding site at the ends of Mu DNA as monomer, and subsequently function as tetramer of MuA (transposase). Host IHF and HU protein were found to aid in formation and stabilisation of LER complex. The LER complex is relatively unstable and so, is rapidly converted into stable synaptic complex (SSC), also known as type 0 complex(17). This is the critical checkpoint before any chemical reaction is carried out as it is the rate-limiting step of cleavage reaction(6). A stable synapse between tetramer of MuA and the two ends of Mu DNA is made but no cleavage is initiated yet at this point. Nonetheless, the active site is structurally occupied to the region around the scissile phosphate while the flanking DNA are destabilized upon formation of the SSC complex(6). In addition to formation of a stable synapse, the Mu ends needs to be properly-oriented, a super coiled DNA topology, and accessory DNA sites are also important to proceed to the next step. Formation of SSC usually is short-lived in presence of Mg2+ but can be accumulated in presence of suitable divalent cations such as Ca2+,which promotes the formation of SSC(8,17). Next, SSC is converted into a type 1 transposome complex, also called as cleaved donor complex(CDC)(9). The 3 ends of Mu DNA are nicked in presence of Mg2+. Two subunits of MuA tetramer, that are associated with the sites that undergo cleavage, assemble in trans arrangement which favours the strand transfer reaction(5). The formation of CDC can then be thought as the result of donor DNA cleavage step. Type 1 transposome complex exhibits greater stability than the type 0 complex though MuA forms structural and functional core in both transposome complexes(6). In addition of stably bound tetramer of MuA proteins, there are loosely associated MuA proteins present in the CDC as well. In absence of MuB protein, MuA tetramer is unable to promote strand transfer reaction unless these extra MuA proteins are present. MuB protein is an ATP-dependent DNA-binding protein, which also acts as an allosteric activator of Mu transposase (MuA proteins)(21). Transposition can still proceed in absence o f MuB proteins, but MuA protein by itself is only 1% efficient(3). 2.2 Strand transfer step A hallmark of this step is the formation of strand transfer complex (STC), also known as type 2 transposome complex. The end product of STC is formation of a branched molecule(Shapiro intermediate) which is characterized by a covalent interaction between donor DNA and target DNA via 5bp single-stranded gaps and its ÃŽÂ ¸ structure(22). MuB protein first captures a target molecule and bring it to the vicinity of the transposome complex, forming a TC complex(6). Formation of TC complexes rapidly undergo one-step transesterification reaction, which is the rate-limiting step in the strand transfer step. Interestingly, recruiting of target molecules by MuB proteins and formation of TC complexes can occur at several time point during the reaction pathway(6). This is a particularly efficient step to maximize transposition potential as it would speed up rate of strand transfers during transposition. The free 3-OH ends produced from the cleavage step act as nucleophile and attack phosphates of target DNA at the 5 ends. 5-nucleotides long offset nicks are made in the target DNA, generating a staggered arrangement(3). At this stage, the MuA proteins(transposase) are still tightly bound to the branched molecule with single stranded gaps. This pose an obstruction for the assembly of replication fork by host replication factors. The structure of the branched molecule is simplified in (C) of Fig. 4. The forming of this intermediate molecule serves as the critical point which distinguish between conservative and replicative transposition. A widely accepted model is that the resolving of this co-integrate molecule by a special resolvase complex leads to double copies of transposon being made in both donor and target site(REFerence). This is by definition, a replicative transposition pathway. Thus, the strand transfer complex is destabilized and disassembled by a system of eight E. coli host molecular proteins (DnaB helicase, DnaC protein, DnaG primase, DNA polymerase II, single-strand binding protein, DNA gyrase, DNA polymerase I and DNA ligase) and molecular chaperon called ClpX, producing cointegrates(13). This transition from transposome complex to a replisome results in duplication of 5-bp target DNA sequences flanking both ends of Mu DNA. Alternatively, if the bacteriophage Mu is to enter the conservative pathway, the co-integrate molecule is repaired or processed without performing Mu DNA replication. The end product of STC in a conservative transposition is a simple insertion of single mini-Mu element inserted into the target DNA(8). However, the mechanism of this model is poorly understood. Fig. 5: Transposome complexes involved during DNA cleavage complex and DNA strand transfer. (A) A plasmid (gray line) bearing donor mini-Mu element (black line) DNA in the in vitro system is negatively coiled. (B) In presence of host HU protein, Mu A protein bind to the two ends of Mu DNA forming a stable synaptic complex (not shown). Assembly of MuA tetramer produces a nick at each ends of Mu DNA, creating a cleaved donor complex (CDC). (C) Nicked 3 ends of Mu DNA are joined together to target DNA in presence of MuB protein forming a strand transfer complex (STC). MuA tetramer is still tightly bound to the Mu ends in the STC. (D) In replicative transposition, a cointegrate molecule is produced when replication of target DNA initiated from the 3 Mu ends by host replication machinery (13). 3. Replicative transposition Replicative transposition was first suggested by Ljungquist and Bukhari (1977) to occur in situ after induction of lysogens, which means that the Mu prophage was not excised from host chromosome during transposition(14). The lysogens were digested with restriction enzymes which cleaves both host and Mu DNA at specific restriction sites. Two of the fragments from the restriction digests contain both host and Mu DNA, which corresponds to junctions between host and prophage DNA, suggesting that prophage DNA is replicated in situ of host chromosome(19). Several genetic and biochemical predictions made in the Shapiro model have been demonstrated in both in vivo and in vitro studies, hence this model is accepted as a plausible mechanism to explain transposition in phage Mu. Numerous techniques have been done to study the direction of replication of Mu DNA during transposition. Results obtained by annealing of Okazaki fragments to separated strands of Mu DNA shows that more than 80% of Mu molecules replication proceed from left to right end(11,19). Electron microscopical observation of mini-Mu element shows that replicating molecules in vitro replicate from both ends in equal probability'(11,19). Replication of Mu DNA is accepted to be predominantly unidirectional, that is from left towards the right end(20). Intramolecular replication pathway can result in inversion, deletion, and simple insertion while intermolecular events can produce co-integrate molecules(19). In the case of Mu transposition, formation of co-integrate molecule needs to be resolved in order to produce two replicons; one molecule contains transposon and target DNA while another molecule contains transposon and donor DNA(10). 4. Conservative transposition The main characteristic of conservative transposition is that phage DNA is not replicated prior to integration. Upon infection of a susceptible host cell (usually E. coli), Mu employs conservative, or also called non-replicative transposition to transfer its genome to the target site. As discussed earlier, conservative transposition pathway follows single strand nicks at the 3 ends of Mu DNA, of which the exposed 3-OH ends join to the staggered cut target DNA at the 5ends forming a co-integrate molecule. The co-integrate or so-called Shapiro intermediate is repaired and generates a simple insertion in the target DNA though the mechanism is still poorly understood. Shapiro model emphasized on single-stranded nicks at Mu ends, joining of Mu to a staggered double-strand break in target DNA, formation of an intermediate molecule, and shedding of heterogeneous of previous host DNA sequences after ligation in conservative pathway(22). On the other hand, Morisato and Kleckner (1984) proposed a different mechanism based on results with Tn10 transposition. Their model is double-stranded cleavages at the transposon ends generating an excised transposon, which then circularizes via ligation on one of the strands(18). It predicts shedding of host sequences from the Mu DNA ends before ligation into the new target DNA. Study of Mu transposition using plasmid substrates in vitro produced results in favour of the Shapiro model, and hence this model has been widely accepted and used in studies. Fig. 6: A model of conservative transposition which utilizes double-strand cleavages during integration. (A) Transposase bind to the inverted repeats at Mu-host boundary sites and cleaves off the transposon away. (B) Transposase made a staggered cut at target sequence of which exposed 3-OH ends of transposon attacks 5-phosphate ends of the host (not shown). The transposon then joins to the host sequence. Duplicated target sequence of 5-bp are completed by host replication machinery (7). The debate on single-strand or double-strand cleavage however does not end there. If phage Mu were to utilize the Shapiro model of transposition during integration (the well-established cointegrate mechanism), the flanking host sequences would remain bound to Mu ends. This would clearly pose a problem as subsequent target-primed replication of the linear integrant would not work, or simply break the chromosome(1). Evidently, results from in vitro experiments are against this as the transposition end products contain transposon, suggesting a complete transposition process have been accomplished. So, does the infecting Mu DNA utilize the Shapiro model where the cointegrate molecule gets processed and repaired, prior to replication at the flanking sequence? Or does it follow a cut-and-paste mechanism where both strands of Mu DNA gets cleaved off from the flanking host DNA sequence (as illustrated in Fig. 6), where no cointegrate molecule is generated, which eventually means, there is no need for resolve by replication? An in vitro experiment was done by Au et al. (2006) to observe the fate of flanking host DNA sequences upon phage Mu infection. Specific markers specific to the infecting phage Mu DNA as well as the donor host (lacZ/proB) were used. These markers were acquired from the host in which the phage had been propagated but absent in the host being infected(1). Upon infection of plasmids by bacteriophage Mu, signal for flanking sequences and Mu DNA were detected in the chromosome at the same time point (approximately at minute 8), which correspond to the integration time point of Mu. Subsequent expression of lacZ and proB were detected maximally at minute 15, significantly reduced at minute 30 and by minute 50, expression were halted(1). Maximal expression at minute 15 most likely corresponds to climax of integration of the infecting phage population. These findings strongly suggest that flanking sequences get integrated together with Mu DNA into the new target site and are subsequently, rem oved by a special mechanism(which explained the undetectable expression at minute 50). This then proves that infecting phage Mu employs an alternate cointegrate mechanism (also called as nick-join-process mechanism) in conservative transposition pathway, where the Mu DNA undergo single-strand nicks, joins to the target DNA, and repaired before replication of the 5-bp gap left by the flanking sequence(1). The mechanism of removal and repair of host flanking sequence however, remains ambiguous. Conclusion Dual nature of bacteriophage Mu, a transposable element and a virus, is certainly interesting but what is more fascinating is that it utilizes both replicative and non-replicative transposition throughout its life cycle. The former mechanism produces a transposon copy in both donor and target DNA while the latter usually generates a simple insertion of transposon in the target DNA, leaving a gap in the host DNA which most likely will get degraded. In the early stages, both replicative and conservative transposition pathway share a similar mechanism. Regardless of the transposition pathway, infecting Mu DNA during the first round of infection will integrate its DNA into the target chromosome via two critical steps; donor DNA cleavage step and strand transfer step. Mu uses a phosphoryl transfer involving nucleophilic attacks of water on phosphodiester bonds of Mu DNA, producing single-strand nicks. A second nucleophilic attack by exposed 3-ends of Mu DNA on 5-ends of target phosphodiester bonds, which then joins the Mu DNA to target DNA via one-step transesterification mechanism. A series of transposome complexes are formed throughout these processes including Mu-encoded MuA proteins(transposase) and MuB proteins(ATPase). A cointegrate is produced in both pathways but in replicative transposition, this intermediate molecule is resolved producing two replicons with transposon copy in each molecule. In conservative transposition, the cointegrate is repaired generating a simple insertion in the target DNA. Hence, it is more accurate to name conservative transposition as nick-join-process rather than the conventional cut-and-paste mechanism as the latter suggest double-strand nicks at the transposon end, which has been proven inaccurate by in vitro experiments. Both transposition pathways have been compared extensively in this review but much of functional core of the mechanisms remain to be understood. (2944 words)

Maxson Rose, a Truly “Rose Woman”

Shuyang Ye Dr. Toni J. Morris ENGL 102 – 54 17. Feb. 2012 Maxson Rose, a Truly â€Å"Rose Woman† Roses are regarded as the most beloved flowers in the world, with its romantic meaning . In most occasions, rose represents love ,beauty and pleasure. Nevertheless, we seldom take rose into deep consideration. Regardless of its sweet side, this kind of flower with thorns shows its another unique characteristics—- dependent, and has a strong awareness of self-protection.The supporting role Maxson Rose in August Wilson’s play â€Å"Fences† takes on both sides of the characteristics of that flower. In the play, Rose puts the family’s unity at the most important place in her heart. Just as the title of the play Fences implies, she wants to build a fence around her family , not letting her family members hurt by others. She performs very well not only between Troy and Cory, but also Troy and Gabriel. From my point of view, she is a bridge between her h usband and son.We know from the play that Troy spent 15 years in prison, and became very good at baseball during the time in prison. But he always lives in the past , he prevents his son playing football in school team just because , he doesn’t want his son do better job in the field where he has no chance to become successful . Rose demands once and once again to persuade Troy to permit Cory play the football , and she always stops the argument between Cory and Troy about football. At the same time , she shows her sincere sympathy to Troy’s disabled brother Gabriel.She gave biscuits to Gabe though he wandered off; she tries to persuade Troy not to t live in the house which is paid by Gabe’s disabled subsidies for granted; and she also stops Troy from sending Gabe to mental hospital. Furthermore, she really plays the roles as flowers, especially she finally decides to accept Troy’s illegitimate daughter Raynell, Instead of begrudging the stagnant situatio n, she choose to bravely confront with the cruel fact that her husband has love affair with another woman as a way of self-protection. She said to Troy: Okay, Troy†¦you’re right.I’ll take care of your baby for you†¦ ‘cause †¦like you say†¦she’s innocent†¦and you can’t visit the Sins of the father upon the child. A motherless child has got a hard time. (she takes the baby from him. ) From right now†¦ this child got a mother. But you a womanless man. (1613) Maxson Rose is an ever-dutiful 1950s-era housewife, devoting herself to her husband and her family. But she do not let her husband Troy walking all over her when she learns about Troy’s love affair with Alberta.Even though their marriage seems draw a close emotionally, Rose tries her best to show sincere motherly qualities to Troy and Alberta’s illegitimate daughter Raynell. And at the end of the play , it is this generous and tolerant woman calling famil y’s unity and asks other family members to forgive Troy. She is truly a rose woman. Work cited August, Wilson. Fences. Literature: Reading, Reacting, Writing. Ed. Laurie G. Kirszner and Stephen R. Mandell. 7th ed. Boston: Wadsworth, 2010. 1572-625. Print.

Evidence Law – Imposing Legal Burden of Defendant

Imposing a legal burden upon a defendant will negate the principle of presumption of innocence. If a defendant has to prove their innocence than it would automatically and unconsciously bring up the issue that they were never considered innocent until proven guilty. The presumption of innocence was first articulated in the case of Woolmington v DPP [1935] AC 462, 461 where Viscount Sankey LC stated that: ‘Throughout the web of English criminal law one golden thread is always to be seen, that it is the duty of the prosecution to prove the prisoner’s guilty subject to†¦No matter what the charge or where the trial, the principle that the prosecution must prove the guilt of the prisoner is part of the common law of England and no attempt to whittle it down can be entertained’ This statement of the nature of the legal burden of proof in criminal trial is basically a summary of the important presumption that highlights our criminal justice system, that a person is presumed innocent till proven guilty. In the case of McIntosh v Lord Advocate [2001] 3 WLR , Lord Bingham referred to the judgement of Sachs J in the case of State v Coetzee [1997] where the importance of the principle as explained.Lord Bingham explained that: The starting point of any balancing enquiry where constitutional rights are concerned must be that the public interest in ensuring that innocent people are not convicted†¦ Hence the presumption of innocence, which serves not only to protect a particular individual on trial, but to maintain public confidence in the enduring integrity and security of the legal system’. The presumption of innocence is supported by the European Convention of Human Rights; Article 6(2) states that ‘anyone charged with a criminal offence shall be presumed innocent until proven guilty according to law’.Furthermore the Human Rights Act 1998 supports the presumption of innocence as well as the European Convention of Human Right s. An issue that is faced by the court in respect of cases is whether imposing a legal burden of proof on the defendant will raise issues with article 6(2) of ECHR as well as the Human Rights Act 1998. In addition the same can be said about legislation that imposes a statutory defence for the defendant to use, and in order for them to use that defence they will bear the legal burden.Even at Common law Lord Viscount Sankey himself stated that it is upon the prosecution to prove guilty, but if a defendant uses the defence of insanity than he shall bear the legal burden of proof. Despite the rule in Woolmington v DPP, there are circumstances where the burden of proof does pass to the accused. This is known as the ‘reverse burden’ or reverse onus’. There are many express statutory exceptions to offences which place’s a legal burden upon the defendant and failure to do so could mean a potential conviction.The Homicide Act 1957, s2(2) imposes a burden of proof o n the accused in relation to suffering from diminished responsibility. It states: ‘On a charge of murder, it shall be for the defence to prove that the person charged is by virtue of this section not liable to be convicted of murder’. There is similar reverse burden on the accused to prove insanity under the common law rule in M’Naghten’s Case [1843] 10 CL & Fin 200. Furthermore the Magistrates Courts Act 1980 s101, places a burden on the defendant but impliedly.It states that ‘where a defendant relies for his defence on any exception, exception, exemption, proviso, excuse or qualification†¦ the burden of proving †¦. shall be on him’. In the case of R v Edwards [1975] QB 27, the defendant was convicted of selling alcohol without a license. The defendant tried to appeal on the grounds that prosecution had not produced any evidence in relation to him being granted a license. The Licensing Act 1964, section 160 clearly states ‘if any person sells†¦ any intoxicating liquor without holding a justices license †¦ hall be guilty of an offence’. The appeal was dismissed on the grounds that under common Law, where a statue forbids an act in certain situations, the court could interpret such that the burden of proving that situation, including granting of a license could like on the defendant. In addition to this s1(1) of Prevention of Crime Act 1953 clearly states that ‘Any Person who without lawful authority or reasonable excuse, the proof whereof shall lie on him, has with him in any public place any offensive weapon shall be guilty of an offence’.This is example of implied statutory exception which imposes a burden of proof upon the defendant. Another example of a case where it was impliedly stated by statue is the case of Gatland v Metropolitan Police Commissioner [1968] 2 AII ER 100 QB. A lorry driver drove into a builder’s skip which had been left in front of building were builders were working. The owners of the lorry claimed against the company which supplied the skip. It was held that the burden was on the rosecution to prove that the skip had been left outside the building and that it could have caused danger to the driver, the burden was on the defendant to prove that it was there with ‘lawful authority or excuse’, this was due to the Magistrates Court Act 1980 section 101. However the courts have imposed limitations on this principle and this was portrayed in the case of R v Hunt 1987 AC 352. This case involved the defendant being convicted of unlawful possession of Morphine in respect of section 5 of the Misuse of Drugs Act 1971.The regulation provided that section 5 will have no effect if the morphine was less than 0. 2%. The defendant tried to appeal on the grounds that prosecution had failed to adduce enough evidence on the proportion of morphine. The trial judge at first instance upheld the conviction and stated that the legal burden fell on the defendant to prove. The defendant appealed by leave of court, and Lord Griffith gave a judgement in that since Woolmington v DPP [1935] a rule was not established that the burden of establishing a statutory defence lay on the defendant only where the statue expressly provides it.He also referred to the case of Nimmo v Alexander Cowan & Sons Ltd 1968 AC 107, where it was agreed that it was not clearly stated that the burden would like on the defendant, and that the courts should take into consideration what the intention was of the Parliament. Lord Griffith went onto say that section 5 of the Act only made it an offence to carry the illegal substance in possession. So therefore it was up to the prosecution to prove that the substance was carried in an illegal form. The burden was on the prosecution to prove that the substance was unlawful and also that the morphine was not in a legal form and not under 0. %. The appeal was allowed and the defendant’s convic tion was quashed. This case illustrates that the courts are not always willing to place the legal burden on the defendant especially when statue is not clear as to the intention of who would bear the burden. Following the performance of the Human Rights Act 1998 section 3 the courts have been required to consider whether the imposition of the burden of proof on the defendant is incompatible with the right to a fair trial under Article 6 ECHR. It also should employ the attitude that all reverse burdens f proof should be viewed as evidential burdens rather than legal, at least for offences with an identified guilt and rigorous sentences. In the case of R v Lambert [2001] 2 Cr App R 511, HL, the defendant was convicted under section 5 of The Misuse of Drugs Act 1971 for possession of cocaine with intent to supply and was sentenced to seven years imprisonment. He relied on section 28(3)(b)(i) of the Act as a defence that he did not believe or suspect, or have reason to suspect that he w as carrying the cocaine.The judge directed the jury in agreement to the law that the prosecution only had to prove that he had and knew that he had possession of cocaine in his bag. The Act imposed a reverse burden on him in relation to this defence. On appeal against the conviction, the defendant tried to argue that the reverse burden that he carried contravened Art 6(2) even though the HRA 1998 was not yet to come into force. The court of appeal held that because the Act had not come into force he could not rely on the convention rights.The result of s28 of the Act was to impose only an evidential burden on the accused, as imposing a legal burden on the defendant would contravene Article 6 of ECHR. It was addressed that imposing a legal burden on a defendant would require a high level of explanation to be actually compatible with Article 6. Lord Steyn said that the burden is on the state to show that the legislative means adopted where not greater than necessity. He also went to e xplain that there must be a ‘pressing necessity’ for a legal burden to be placed upon the defendant.However in the case of R v Johnstone [2003] UKHL 28 HL, the defendant as charged with an offence under s92 of the Trade Marks Act 1994, in relation to production and sale of counterfeit CD’s involving reproducing the trademarks of the various artists. The defence that could be relied on was under s92(5) which claimed: ‘It is a defence for a person charged with an offence under this section to show that he believed on a reasonable grounds that the use of the sign in the manner in which it was used, or was to be used, was not an infringement of the registered trade mark’.It was held that the placing of a legal burden of proof on the accused was compatible with article 6 of ECHR. Lord Nichollos gave the judgment that ‘Given the importance and difficulty of combating counterfeiting, and given the comparative ease with an accused can raise and issue a bout his honesty, overall it is fair and reasonable to require a trader, should need arise, to prove on the balance of probability that the honestly and reasonably believed the goods were genuine’. This clearly indicates that in certain circumstances the ECHR article 6 can be infringed upon if the crime is detrimental in society as well as raising issues of honesty.It can be inferred that the decisions made in Lambert and Johnstone have caused friction as both offences have given way to a defence through statutory exceptions. In Johnstone it was only an evidential burden that was placed in the defendant whereas in Lambert a legal burden was placed. However a common ground which both cases have come to is that a case would have to have great justification to go against article 6 of ECHR and the Human Rights Act 1998. An issue that arises is what would constitute as having great justification and that there is a lack of clarity in this.It can be said that judges have not interp reted properly statutes that impose a burden of proof on the defendant, and therefore cases are resulting in different outcomes. Furthermore this can be seen again in the case of Sheldrake v DPP; Attorney General’s Reference (No 4 of 2002) UKHL 43 HL. The hearing before the court was raised as a result of two different cases. The first case involved the defendant being charged under s5(1) of the Road Traffic Act 1988 for being charge of a motor vehicle after having being intoxicated by so much alcohol, going over the required limit.The defendant tried to rely on the defence provided under s5(2) of the Act ‘that at the time he alleged to have committed the offence the circumstances†¦. likely to exceed the prescribed limit’. The defendant tried to claim that if an evidential burden was not placed than it would intervene with ECHR article 6. It was held that, even if it did contravene Article 6, that it would be justified by the fact that it was proportionate a nd directed towards a legitimate objective.The second case involved the defendant being charged and convicted under the Terrorism Act 2000, and a defence was available from section 11(2) for a defendant ‘ that the organisation was not a proscribed on the last (or only) occasion on which he became a member or began to profess to be a member, and that he has not taken part in the activities of the organisation at any time while it was proscribed’. Take into consideration that the statue states that it is a defence to the offence, but does not state that the burden is upon the defendant to prove.The court stated that once the defendant had raised the issue and satisfied the evidential burden of proof it was up to the prosecution to rebut that evidence rather than the defendant having to undergo the legal burden of proof. It was held that in relation to s11 it would be incompatible with article 6 if interpreted as imposing a legal burden and therefore should be ‘read down’ so it only imposed an evidential burden. In conclusion to this assignment it can be seen that judges are more conscious about placing a legal burden upon the defendant as it does intervene with ECHR article 6.Judges have tried to justify in situation where a legal burden if placed on a defendant, by stating where a crime is so severe with harsh imprisonment a defendant does have to prove the legal burden. In certain situations where the reverse burden is transferred the courts are willing to place an evidential burden on the defendant rather than legal however where there is a statutory defence judges may go either way by stating that the legal burden has to be proved or that an evidential burden maybe placed.Furthermore a problem that statutory defences poses is that judges maybe unclear as to the wording of the provision so therefore there is not much clarity and confusion maybe caused. Furthermore the same can be said about implied statutory exceptions as the wording does not expressly say that the burden is on the defendant again this can cause confusion and sometimes result in the defendant having the burden. In all the courts are more willing to be flexible and only when there is a necessity in placing the burden with great justification will the courts impose a burden upon the defendant.I do agree that placing a burden on the defendant does negate the principle of presumption of innocence but I would agree with the courts that sometimes it is necessary to do so. Word count: 2655 Bibliography Cases McIntosh v Lord Advocate [2001] 3 WLR Woolmington v DPP [1935] AC 462, 461 Gatland v Metropolitan Police Commissioner [1968] 2 AII ER 100 QB R v Lambert [2001] 2 Cr App R 511, HL Sheldrake v DPP; Attorney General’s Reference (No 4 of 2002) UKHL 43 HL R v Edwards [1975] QB 27 of R v Hunt 1987 AC 352 Books C TaylorEvidence Pearson Education Limited 1st Edition 2010C Allen A Practical Guide To Evidence Cavendish Publishing 4th Edition 2008 Tab le of Statue Homicide Act 1957 Human Rights Act 1998 Licensing Act 1964 Magistrates Court Act 1980 Misuse of Drugs Act 1971 Prevention of Crime Act 1953 Road Traffic Act 1988 Trade Marks Act 1994 EU Legislation European Convention of Human Rights Journal http://webjcli. ncl. ac. uk/2003/issue3/cooper3. html Simon Cooper Human Rights & Legal Burden of Proof Accessed 27/07/12 Website http://conventions. coe. int/treaty/en/treaties/html/005. htm Accessed 02/08/12 http://www. legislation. gov. uk/ukpga/1998/42/section/3 Human Rights Act 1998 s3 Accessed 12/08/12 ttp://www. hartpub. co. uk/updates/crimlaw/crimlaw_burden05. htm Burden of Proof, Accessed 12/08/12 http://www. lawgazette. co. uk/news/r-v-hunt-richard Accessed 06/08/12 http://www. lawgazette. co. uk/news/r-v-hunt-richard Accessed 06/08/12 ——————————————– [ 1 ]. http://webjcli. ncl. ac. uk/2003/issue3/cooper3. html Simon Co oper Human Rights & Legal Burden of Proof Accessed 27/07/12 [ 2 ]. McIntosh v Lord Advocate [2001] 3 WLR Judgement of Lord Bingham [ 3 ]. http://conventions. coe. int/treaty/en/treaties/html/005. htm Accessed 02/08/12 [ 4 ]. Woolmington v DPP [1935] AC 462, 461 [ 5 ]. http://www. egislation. gov. uk/ukpga/Eliz2/5-6/11/section/2 Homicide Act 1957 s2(2) [ 6 ]. C TaylorEvidence Pearson Education Limited 2010 pg 15 [ 7 ]. http://www. legislation. gov. uk/ukpga/1980/43/section/101 Magistrates Courts Act 1980 s101 [ 8 ]. R v Edwards [1975] QB 27 [ 9 ]. Gatland v Metropolitan Police Commissioner [1968] 2 AII ER 100 QB [ 10 ]. of R v Hunt 1987 AC 352 [ 11 ]. http://www. lawgazette. co. uk/news/r-v-hunt-richard Accessed 06/08/12 [ 12 ]. http://www. lawgazette. co. uk/news/r-v-hunt-richard Accessed 06/08/12 [ 13 ]. http://www. legislation. gov. uk/ukpga/1998/42/section/3 Human Rights Act 1998 s3 Accessed 12/08/12 [ 14 ]. ttp://www. hartpub. co. uk/updates/crimlaw/crimlaw_burden05. htm Burden of Proof, Accessed 12/08/12 [ 15 ]. R v Lambert [2001] 2 Cr App R 511, HL [ 16 ]. R v Lambert [2001] 2 Cr App R 511, HL [ 17 ]. C Allen A Practical Guide To Evidence Cavendish Publishing 2008 pg 168 [ 18 ]. R v Johnstone [2003] UKHL 28 HL [ 19 ]. R v Johnstone [2003] UKHL 28 HL [ 20 ]. Sheldrake v DPP; Attorney General’s Reference (No 4 of 2002) UKHL 43 HL [ 21 ]. http://www. legislation. gov. uk/ukpga/2000/11/section/11 [ 22 ]. Sheldrake v DPP; Attorney General’s Reference (No 4 of 2002) UKHL 43 HL

A Brief Note On Business Ethics And Social Responsibility

QUESTION 1 1.1.1 Social Responsibility – Social responsibility is the limiting of malpractice through regulation. It is measured by the contribution of a business towards the economy and the employment opportunities. (Erasmus, Strydom and Rudansky-Kloppers, 2015: 9) Employment Equity – Employment equity strives to produce equal employment opportunities for all members of the community. In 1998, the Employment Equity Act became law in South Africa and was designed to eradicate unfair discrimination and create a diverse workplace that represents all of South Africa’s population groups. (Erasmus, Strydom and Rudansky-Kloppers, 2015: 9) Business Ethics – Business ethics are linked to social responsibility, however, it focuses on the â€Å"ethical behaviour of managers and executives in the business world† (Erasmus, Strydom and Rudansky-Kloppers, 2015: 11). Many businesses have implemented a ‘code of business conduct’ to ensure that all executive members and managers have a precise outline of what is considered to be ethical in the business environment. (Erasmus, Strydom and Rudansky-Kloppers, 2015: 11) Consumerism – â€Å"Consumerism is a social force that protects consumers against unsafe products and malpractice by exerting moral and economic pressure on businesses† (Erasmus, Strydom and Rudansky-Kloppers, 2015: 11) Environmental Sustainability – Environmental sustainability is the pressure placed on businesses to protect the environment from all types off pollution. (Erasmus, StrydomShow MoreRelatedImportance Of Corporate Social Responsibility On Todays Society1136 Words   |  5 PagesImportance of Corporate Social Responsibility in today’s society Before five years, I came across a situation which led me to think about the importance and need of social responsibility by business enterprises. To start off giving a brief background, my brother was a fresh graduate from the school of architecture where he got his first individual contract in India. He had to design a mall that was planned to kick start after few years. The land where it was being constructed belonged to an oldRead MoreEthical System Table Essay958 Words   |  4 PagesDirections: 1. Fill in brief definitions of each primary ethical theory. 2. Identify alternate names or variations of each ethical system based on your reading of the text and supplemental materials. Match the real-world examples listed below with the corresponding systems. The first one has been completed for you in the table. a. I believe people should be able to eat sand if they like the taste of it. b. I believe that if sand is going to be eaten, it should beRead MoreImportance Of Corporate Social Responsibility On Todays Society1293 Words   |  6 PagesJait Shukla ENG W 131 Essay 2 Importance of Corporate Social Responsibility in Today’s Society Before five years, I came across a situation which led me to think about the importance and need of social responsibility by business enterprises. To start off giving a brief background, my brother was a fresh graduate from the school of architecture where he got his first individual contract in India. He had to design a mall that was planned to kick start after a few years. The land where it was beingRead MoreThe Sarbanes Oxley ( Sox ) Act Of 20021617 Words   |  7 PagesThe focus of this week’s assignment is the Sarbanes-Oxley (SOX) Act of 2002. A brief historical summary of SOX will be presented, including the events leading up to its passage. The key ethical components of SOX will be identified and explained. The social responsibility implications of the mandatory publication of corporate ethics will be assessed. One of the main criticisms of SOX has been its implementation costs, and this specific criticism will be addressed in regards to smaller organizationsRead M ore Aristotle Essay777 Words   |  4 Pageshave been completely lost. Only a few brief excerpts of some of his technical notes have survived. However, the texts on which Aristotles reputation rests are largely based on his lecture notes for carefully outlined courses, which were collected and arranged by later editors. Among the texts are dissertations on: logic, called Organon; natural sciences, called Physics; nature, scope and properties of being, called Metaphysics; and ethics, called Nicomachean Ethics (dedicated to his son Nicomachus)Read MoreBusiness Environment5822 Words   |  24 PagesMODULE -3 Business Around Us Notes 3 BUSINESS ENVIRONMENT nderstanding the environment within which the business has to operate is very important for running a business unit successfully at any place. Because, the environmental factors influence almost every aspect of business, be it its nature, its location, the prices of products, the distribution system, or the personnel policies. Hence it is important to learn about the various components of the business environment, which consists of the economicRead MoreAdvantages And Disadvantages Of Computer In Business1665 Words   |  7 PagesThe use of computers in business and research has completely changed the way society operated decades ago. The purpose of this article is to discuss three advantages and disadvantages of the Information System in Business that I have experienced and the consequences of using computers; as well as a brief acknowledgement on computer ethics and the impact of computers in society. Research findings indicate that the use of computers do pose positive effects on the continuous achievements of numerousRead MoreManaging Human Resources Quiz 4 Review Chapters 1 Thru 41463 Words   |  6 PagesManaging Human Resources | Quiz 3 | Review: Chapters 1 thru 4 Student: There are Multiple-choice, True or False, and Short Essay questions. Note: All questions also require a brief response explaining the reason for your answer. Circle the correct multiple choice answer; or check (ïÆ'â€") the correct answer for True or False statements 1. When the human resources function creates a unique capability in a firm that creates high value and differentiates the organization from its competition, human resourcesRead MoreCorporate Social Responsibility At Adam Smith s The Wealth Of Nations Essay1667 Words   |  7 PagesIntroduction The subject of corporate social responsibility raises a peculiar, yet necessary question if its concept is to be understood: why do businesses exist? There are several was to answer this question, but none comes as close enough as the content contained in Adam Smith’s The Wealth of Nations. According to Smith (2005), all individuals work for their own interests. This is affirmed by Hodgson (2004), who states that opportunism defines the transactional world of economic man. In the yearsRead Morebusiness law chap 92036 Words   |  9 Pagesï » ¿ DE PAUL UNIVERSITY COLLEGE OF COMMERCE DEPARTMENT OF MANAGEMENT BUSINESS LAW - 201 INSTRUCTOR: SAMUEL B. GARBER, M.B.A., J.D. PHONE: 312-362-6788 Course Description: Legal Environment of Business: History of law from the Common Law down to the present Uniform Commercial Code, including ethical considerations and social responsibilities fundamental principles of law pertaining to business and persons, contracts and principal-agent relationship. (Prerequisite: Sophomore Standing)