Biotechnology and Genetic Engineering Reviews最新文献_第2页

Cyanobacterial Exopolysaccharides: Their Nature and Potential Biotechnological Applications 蓝藻胞外多糖:它们的性质和潜在的生物技术应用

Biotechnology and Genetic Engineering Reviews Pub Date : 2001-07-01 DOI: 10.1080/02648725.2001.10648020

Pengfu Li, S. Harding, Zhi-li Liu

{"title":"Cyanobacterial Exopolysaccharides: Their Nature and Potential Biotechnological Applications","authors":"Pengfu Li, S. Harding, Zhi-li Liu","doi":"10.1080/02648725.2001.10648020","DOIUrl":"https://doi.org/10.1080/02648725.2001.10648020","url":null,"abstract":"Cyanobacteria (blue-green algae) are photosynthetic prokaryotic organisms which are unicells or filaments. Of great significance biologically is the fact that certain cyanobacteria can fix elemental nitrogen (Carr and Whitton, 1982). Some cyanobacteri a are capable of movement by gliding when in contact with the substrate (Bold and Wynne, 1985). Some cyanobacteria have the ability to survive desiccation and extremes of temperature, and can grow at high pH and salinity (Flaibani et al., 1989). Cyanobacteria occur in most environments on earth. Their distribution in freshwater and marine environment is cosmopolitan. Cyanobacteria are also commonly found in the soil and in rocks from the tropics to polar regions, and from temperate climates to extreme arid deserts, where they sometimes participate in the formation of microbial crusts or mats (Bold and Wynne, 1985; Mazor et al., 1996). A number of diazotrophic cyanobacteria grow easily in association or symbiosis with certain green algae, liverworts, water ferns, and angiosperms (Bold and Wynne, 1985). Cyanobacteria have been known, for a long time, to produce large amounts of exopolysaccharide (Drews and Weckesser, 1982). Recently, this massive production has received increasing attention due to the potential applications of these substances as industrial gums, bioflocculants, soil conditioners and biosorbants, and to their participation in symbiotic processes in plants, in the gliding movement, and in the general interactions between microorganisms and their habitats (Bertocchi et al., 1990; Painter. 1993; Morvan et al, 1997; De Philippis and Vincenzini, 1998).","PeriodicalId":8931,"journal":{"name":"Biotechnology and Genetic Engineering Reviews","volume":"14 1","pages":"375 - 404"},"PeriodicalIF":0.0,"publicationDate":"2001-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72882593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 99

Biotechnological Approaches to Fight Pathogens at Mucosal Sites 在粘膜部位对抗病原体的生物技术方法

Biotechnology and Genetic Engineering Reviews Pub Date : 2001-07-01 DOI: 10.1080/02648725.2001.10648018

C. Kelly, D. Medaglini, Justine S. Younson, G. Pozzi

{"title":"Biotechnological Approaches to Fight Pathogens at Mucosal Sites","authors":"C. Kelly, D. Medaglini, Justine S. Younson, G. Pozzi","doi":"10.1080/02648725.2001.10648018","DOIUrl":"https://doi.org/10.1080/02648725.2001.10648018","url":null,"abstract":"Most interactions between host and pathogens occur at the host mucos al surfaces. Many pathogens, such as the human immunodeficiency virus (HIV), gain entry via the mucosa while others, including Candida, Streptococcus mutans and Helicobacter pylori , must become established at the mucosa to cause damage to the host. Strategies aimed at controlling pathogens at mucosal surfaces and infectious diseases in general are summarized in Figure 13.1. These include primarily vaccination and the use of antimicrobial chemotherapy, particularly antibiotics, which have both had an enormous impact on infectious disease (Cohen, 2000). Passive immunization has been used less with the advent of vaccines and antibiotics but is of increasing importance for treatment of immunocornpromised patients (Hammarstrom, 1999) whilst the development and use of topical microbicides is regarded as a potentially important means of preventing infection with HIV (Lange et al., 1993). Pathogens at mucosa( sites, however, present particular problems for these measures, e.g. antibiotics can be very effective in clearing systemic infections while being unable to affect mucosal carriage of the pathogen. A limited number of vaccines induce protective mucosal responses and vaccines are not yet available for several microorganisms that infect rnucos al surfaces. These observations, together with concern over the spread of antibiotic resistance (Hawkey, 1998; Irvin and Bautista, 1999), have stimulated investigation of additional antimicrobial strategies as well as refinement of existing approaches.","PeriodicalId":8931,"journal":{"name":"Biotechnology and Genetic Engineering Reviews","volume":"1 1","pages":"329 - 347"},"PeriodicalIF":0.0,"publicationDate":"2001-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80422335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Kinetic Analysis for Analyte-Receptor Binding and Dissociation in Biosensor Applications: a Fractal Analysis 生物传感器应用中分析物-受体结合和解离的动力学分析:分形分析

Biotechnology and Genetic Engineering Reviews Pub Date : 2001-07-01 DOI: 10.1080/02648725.2001.10648007

A. Sadana

{"title":"Kinetic Analysis for Analyte-Receptor Binding and Dissociation in Biosensor Applications: a Fractal Analysis","authors":"A. Sadana","doi":"10.1080/02648725.2001.10648007","DOIUrl":"https://doi.org/10.1080/02648725.2001.10648007","url":null,"abstract":"To acquire an understanding of biological processes at the molecular level requires two basic approaches: structural and functional analysis. Under ideal conditions these should complement each other and provide a complete picture of the molecular processes. Electron microscopy, sequence analysis, mass spectroscopy, X-ray and electron diffraction studies are routinely employed as structural techniques. These provide information about the atomic organization of individual as well as interacting biomolecules, but these have the disadvantage of being static and ’frozen’ in time. Functional investigation techniques like affinity chromatography, immunological techniques, and spectrophotometric techniques give valuable information on the conditions and the specificity of the interaction, but are (a) unable to follow a process in time, or (b) are too slow to be rendered suitable for most biospecific interactions. Moreover, these techniques demand some kind of labelling of interactants which is undesirable as it may interfere with the interaction and this will necessitate purification of the interactants in large quantities. A promising area in the investigation of biomolecular interactions is the development of biosensors. These biosensors are finding application in the areas of biotechnology, physics, chemistry, medicine, aviation, oceanography, and environmental control. These sensors or biosensors may be utilized to monitor the analytereceptor reactions in real time (Myszka et al., 1997), besides some techniques like the surface plasmon resonance (SPR) biosensor do not require radiolabelling or biochemical tagging (Jonsson et al., 1991), are reusable, have a flexible experimental","PeriodicalId":8931,"journal":{"name":"Biotechnology and Genetic Engineering Reviews","volume":"15 1","pages":"29 - 48"},"PeriodicalIF":0.0,"publicationDate":"2001-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82547364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Regulation of Muscle Glycogen Phospfaorylase by Physiological Effectors 肌糖原磷酸化酶的生理效应调控

Biotechnology and Genetic Engineering Reviews Pub Date : 2001-07-01 DOI: 10.1080/02648725.2001.10648016

N. Chebotareva, S. V. Klinov, B. Kurganov

{"title":"Regulation of Muscle Glycogen Phospfaorylase by Physiological Effectors","authors":"N. Chebotareva, S. V. Klinov, B. Kurganov","doi":"10.1080/02648725.2001.10648016","DOIUrl":"https://doi.org/10.1080/02648725.2001.10648016","url":null,"abstract":"The enzyme from rabbit skeletal muscle contains 842 amino acid residues and the essential cofactor pyridoxa1-5’-phosphate is linked through its aldehyde group to the &amino group of Lys680. The polypeptide chain can be divided in two domains, both of them having an-sheet core surrounded by a-helices. The main oligomeric form of the enzyme is a dimer. The interactions between identical subunits are relatively few in dephosphorylated form of the enzyme (phosphorylase b). The main contacts involve the cap (residues 36 to 45) and the tower (residues 260 to 276) of symmetryrelated subunits. X-ray crystallographic studies reveal four ligand-binding sites: catalytic site, allosteric effector site, glycogen storage site, and nucleoside inhibitor site (Figure 11.1). The catalytic site is buried in the centre of the subunit where the domains come together. Access to this site is achieved through a narrow channel which is some 1.2 nm long. The access is restricted mostly by the 280s loop (residues 282 to 286). The residues from the 280s loop are displaced upon transition to catalytically active state following motion of the symmetry-related towers. The allosteric effector site is located near the subunit interface and is separated by a distance of 3.2 nm from the catalytic site. The glycogen storage site is 3.0 nm apart from the catalytic site and at a distance of 4.0 urn from the allosteric effector site. The","PeriodicalId":8931,"journal":{"name":"Biotechnology and Genetic Engineering Reviews","volume":"36 1","pages":"265 - 297"},"PeriodicalIF":0.0,"publicationDate":"2001-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72961826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 16

Bioconjugation for Enzyme Technology 酶技术的生物偶联

Biotechnology and Genetic Engineering Reviews Pub Date : 2001-07-01 DOI: 10.1080/02648725.2001.10648015

O. Kwon, Yoshihiro Ito

{"title":"Bioconjugation for Enzyme Technology","authors":"O. Kwon, Yoshihiro Ito","doi":"10.1080/02648725.2001.10648015","DOIUrl":"https://doi.org/10.1080/02648725.2001.10648015","url":null,"abstract":"Enzymes play important roles in all living cells. They possess remarkable catalytic properties in terms of high catalytic activity, exclusion of undesirable side-reactions such as racemization, and operations under mild conditions. The most specific features of enzyme function are the high substrate specificity including regioselectivity and stereospecificity. As a consequence, enzymes have been used in various industrial and medical fields. Bioconjugation has expanded the possibility of application of enzymes towards bioreactor catalyst, bioreactor sensor and medical drug technologies. Immobilization of enzymes onto solid matrices has enabled the recyclization of enzymes: immobilization of enzymes onto sensing devices including electrodes and optodes has also provided the basis for biochemical sensors. Bioconjugation of medical enzymes extracted from animals with an amphiphilic polymer, polyethylene glycol, has been shown to reduce the immuno-reaction induced by the application of sensor or therapeutic enzymes into the human body. Various bioconjugations of biological molecules are very important in the biomedical fields (Aslam and Dent, 1998). Bioconjugation is divided into two categories in the present review. One is geneengineered bioconjugation, and the other chemically engineered bioconjugation (Figure 10.1). Gene-engineered modification has been used for the alteration of enzymatic activity, such as thermal stabilization (Bryan et al., 1986), alteration of","PeriodicalId":8931,"journal":{"name":"Biotechnology and Genetic Engineering Reviews","volume":"19 1","pages":"237 - 263"},"PeriodicalIF":0.0,"publicationDate":"2001-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85580656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Expression of Insulin in Yeast: The Importance of Molecular Adaptation for Secretion and Conversion 胰岛素在酵母中的表达:分子适应对分泌和转化的重要性

Biotechnology and Genetic Engineering Reviews Pub Date : 2001-07-01 DOI: 10.1080/02648725.2001.10648010

Thomas Kjeldsen, P. Balschmidt, I. Diers, M. Hach, N. Kaarsholm, S. Ludvigsen

{"title":"Expression of Insulin in Yeast: The Importance of Molecular Adaptation for Secretion and Conversion","authors":"Thomas Kjeldsen, P. Balschmidt, I. Diers, M. Hach, N. Kaarsholm, S. Ludvigsen","doi":"10.1080/02648725.2001.10648010","DOIUrl":"https://doi.org/10.1080/02648725.2001.10648010","url":null,"abstract":"The globular, two...chain and 51 amino acid residue peptide-hormone insulin is produced and secreted by the ~-cellsof the pancreatic islets of Langerhans. Insulin is synthesized as preproinsnlin (110 amino acids). The pre-peptide (signal peptide) is removed upon entrance into the endoplasmic reticulum. Proinsulin folds in the endoplasmic reticulum, is transported to the Goigi apparatus and subsequently processed into the mature insulin molecule that is stored in well-defined storage vesicles (Figure 5.1) (Steiner etaI., 1967, 1986; Dodsonand Steiner, 1998). Proinsulin and insulin have self-assembling properties that play an important role in processing and storage in the J3-cell's secretory pathway and both associate to dimers and in the presence of zinc these further assemble into hexamers (Dodson and Steiner, 1998). In the late Golgi apparatus proinsulin is targeted to acidifying secretory granules and conversion ofproinsulin to insulin occurs by removal of the C-peptide by cleavage at dibasic processing sites by the endoproteases PC3 (or PCl) and pe2 (mammalian","PeriodicalId":8931,"journal":{"name":"Biotechnology and Genetic Engineering Reviews","volume":"41 1","pages":"121 - 89"},"PeriodicalIF":0.0,"publicationDate":"2001-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88813392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 27

Gene Structures and Catalytic Mechanisms of Microbial Enzymes Able to Blodegrade the Synthetic Solid Polymers Nylon and Polyester Polyurethaoe 微生物酶溶胀降解合成固体聚合物尼龙和聚酯聚氨酯的基因结构和催化机理

Biotechnology and Genetic Engineering Reviews Pub Date : 2001-07-01 DOI: 10.1080/02648725.2001.10648011

N. Nomura, T. Deguchi, Y. Shigeno-Akutsu, T. Nakajima-Kambe, T. Nakahara

{"title":"Gene Structures and Catalytic Mechanisms of Microbial Enzymes Able to Blodegrade the Synthetic Solid Polymers Nylon and Polyester Polyurethaoe","authors":"N. Nomura, T. Deguchi, Y. Shigeno-Akutsu, T. Nakajima-Kambe, T. Nakahara","doi":"10.1080/02648725.2001.10648011","DOIUrl":"https://doi.org/10.1080/02648725.2001.10648011","url":null,"abstract":"Since the middle of the 20th century, the chemical industry has generated various synthetic compounds as both industrial products and wastes material by-products. Among these synthetic compounds the water-insoluble solid polymers (with the exception of polymers synthesized specifically as biodegradable polymers, such as polylactic acid) are generally the most resistant to microbial attack, an attack which is essentially by enzyme action. An enzyme that is able to catalyze the degradation of a solid polymer must be able to access and bind to the polymer at a specific site, and to catalyze the degradation reaction extracellularly. In general, water-insoluble synthetic polymers are hydrophobic, rigid, and have a small specific surface area as compared to naturally occurring water-insoluble polymers such as cellulose. These properties make the degradation of the water-insoluble synthetic solid polymer difficult. However it has been reported that several water-insoluble synthetic solid polymers are vulnerable to microbial attack. In particular, the characteristics of the genetic sequences and catalytic mechanisms of the microbial enzymes which are able to degrade nylon and polyester polyurethane have been well studied, and this is what we will consider in this review.","PeriodicalId":8931,"journal":{"name":"Biotechnology and Genetic Engineering Reviews","volume":"39 1","pages":"125 - 147"},"PeriodicalIF":0.0,"publicationDate":"2001-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87155154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 26

Pyrolysis in Biotechnology 生物技术中的热解

Biotechnology and Genetic Engineering Reviews Pub Date : 2001-07-01 DOI: 10.1080/02648725.2001.10648006

I. Drevin, B. Johansson, Erika Lars Son

{"title":"Pyrolysis in Biotechnology","authors":"I. Drevin, B. Johansson, Erika Lars Son","doi":"10.1080/02648725.2001.10648006","DOIUrl":"https://doi.org/10.1080/02648725.2001.10648006","url":null,"abstract":"Pyrolysis is the thermal decomposition of molecules in an inert atmosphere. The transfer of thennal energy to a polymeric network or to macromolecules causes degradation of the sample into volatile products. The reaction products are characteristic ofthe original structure and much more easily analysed than the original sample. A significant advantage of the pyrolysis technique is the speed of the analysis~ Complex materials that normally require time consuming analysis can be investigated by this technique coupled to gas chromatography (Py-GC) in less than an hour or with it coupled directly to a mass spectrometer (Py-MS) in a couple of minutes. e.G. Williams' article from 1862 is considered to be the first of its kind in the field of pyrolysis. That study identified isoprene as the main pyrolytic product of robber. However, broad use of analytical pyrolysis has had to wait for the development of modern analytical technology. Today, pyrolysis is widely used to study macro.. molecules, including synthetic and natural polymers (see for example Wampler, 1989), to perform degradation and kinetic studies and also for the qualitative and quantitative analysis of complex substances. Examples of material analysed by pyrolysis are synthetic polymers (for a review, see Blazs6, 1997), coating materials (Haken, 1999), rubber (Dubey et aI., 1995), paper and paper coating, plant material (Ralph and Hatfield, 1991) and bacteria. Pyrolysis is also used in forensic science, art and archaeology (Shedrinsky et aI., 1989). This present review focuses on the analytical pyrolysis of biological macromolecules such as proteins, DNA and microorganisms. The first part of the article presents an overview of the pyrolysis techniques available and the methods for analysis of the pyrolytic products, the pyrolysate. The second part presents some applications to illustrate the types ofproblem that researchers have been able to solve using pyrolysis.","PeriodicalId":8931,"journal":{"name":"Biotechnology and Genetic Engineering Reviews","volume":"45 1","pages":"28 - 3"},"PeriodicalIF":0.0,"publicationDate":"2001-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74915969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Industrial Purification of Pharmaceutical Antibodies: Development, Operation, and Validation of Chromatography Processes 药物抗体的工业纯化:色谱法的开发、操作和验证

Biotechnology and Genetic Engineering Reviews Pub Date : 2001-07-01 DOI: 10.1080/02648725.2001.10648017

R. Fahrner, H. Knudsen, Carol D. Basey, Walter Galan, Dian Feuerhelm, M. Vanderlaan, G. Blank

{"title":"Industrial Purification of Pharmaceutical Antibodies: Development, Operation, and Validation of Chromatography Processes","authors":"R. Fahrner, H. Knudsen, Carol D. Basey, Walter Galan, Dian Feuerhelm, M. Vanderlaan, G. Blank","doi":"10.1080/02648725.2001.10648017","DOIUrl":"https://doi.org/10.1080/02648725.2001.10648017","url":null,"abstract":"Recombinant monoclonal antibodies are becoming a great success for the biotechnology industry. They are currently being studied in many clinical trials for treating a variety of diseases, and recently several have been approved for treating cancer (Carter et al., 1992; Anderson et al., 1996; Baselga et al~, 1996; Bodey et al., 1996; Longo~ 1996). Although there are several types of antibodies produced in different types ofcel1lines, the most clinically significant antibodies are full-length humanized IgG. produced in CHO cells. This review describes the methods used to purify these antibodies at industrial scale, focusing on chromatography processes~ and with particular reference to recent work at Genentech. Routine laboratory purification ofantibodies has been well described (for example see Scott et aL, 1987), but the considerations for large-scale production of pharmaceutical-grade antibodies are much different than those for laboratory scale. There are extreme purity requirements for pharmaceutical antibodies~ and routine large-scale production requires high yield and process reliability. To gain regulatory approval, the process must be completely validated to run consistently within specified limits, so the process should be designed to facilitate validation, Large-scale production of antibodies as pharmaceutical products is a complex","PeriodicalId":8931,"journal":{"name":"Biotechnology and Genetic Engineering Reviews","volume":"170 1","pages":"301 - 327"},"PeriodicalIF":0.0,"publicationDate":"2001-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72752278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 235

Tumour-Selective Salmonella-Based Cancer Therapy 肿瘤选择性沙门氏菌癌症治疗

Biotechnology and Genetic Engineering Reviews Pub Date : 2001-07-01 DOI: 10.1080/02648725.2001.10648014

D. Bermudes, K. Low, J. Pawelek, M. Feng, M. Belcourt, Li-mou Zheng, I. King

{"title":"Tumour-Selective Salmonella-Based Cancer Therapy","authors":"D. Bermudes, K. Low, J. Pawelek, M. Feng, M. Belcourt, Li-mou Zheng, I. King","doi":"10.1080/02648725.2001.10648014","DOIUrl":"https://doi.org/10.1080/02648725.2001.10648014","url":null,"abstract":"Cancer therapies fail for several primary reasons; lack ofdrug effect on the cancerous tissue~ lack of selectivity for the cancerous tissue, andlor inadequate delivery to the target tissue. Drug effect and selectivity can be improved by increased understanding of molecular and cellular differences between cancer and normal tissues, thus enabling the design of drugs that potently affect cancer-specific molecular targets associated with malignant behaviour. Another approach is to improve the selective delivery ofanti-cancer agents to tumours. One approach is to use carriers that bind to cancer...specific targets, such as antibodies (Hall, 1995). However, most targeting approaches, even if selective, tend not to deliver sufficiently high concentrations of the agent to the tumour to induce significant therapeutic effects. Recent findings suggest that the pathogenic bacterium Sallnonella, when genetically modified, can be used to selectively deliver therapeutic agents to solid tumours at high concentrations (Pawelek et ai., 1997; Low et ai., 1999a). These attenuated bacteria are administered either systemically or locally, whereupon they typically replicate 1000 times greater in the tumour than in other tissue. The basis for preferential colonization and accumulation of Salmonella in tumours appears to include some of the same characteristics of tumours that provide resistance to drug and immune-based therapies (Bermudes et aI., 2000a,b). Why tumours are susceptible to Sabnonella is not well understood and probably includes a variety of factors. Poor penetration of components of the immune system, including antibodies, complement, CD8+ T-cells, granulocytes and macrophages","PeriodicalId":8931,"journal":{"name":"Biotechnology and Genetic Engineering Reviews","volume":"86 1","pages":"219 - 233"},"PeriodicalIF":0.0,"publicationDate":"2001-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77499758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 19