Use Of Living Cells Research Articles

Live Cells as Dynamic Laboratories: Time Lapse Raman Spectral Microscopy of Nanoparticles with Both IgE Targeting and pH-Sensing Functions.

This review captures the use of live cells as dynamic microlaboratories through implementation of labeled nanoparticles (nanosensors) that have both sensing and targeting functions. The addition of 2,4-ε-dinitrophenol-L-lysine (DNP) as a FcεRI targeting ligand and 4-mercaptopyridine (4-MPy) as a pH-sensing ligand enables spatial and temporal monitoring of FcεRI receptors and their pH environment within the endocytic pathway. To ensure reliability, the sensor is calibrated in vivo using the ionophore nigericin and standard buffer solutions to equilibrate the external [H+] concentration with that of the cell compartments. This review highlights the nanosensors, ability to traffic and respond to pH of receptor-bound nanosensors (1) at physiological temperature (37°C) versus room temperature (25°C), (2) after pharmacological treatment with bafilomycin, an H+ ATPase pump inhibitor, or amiloride, an inhibitor of Na+/H+ exchange, and (3) in response to both temperature and pharmacological treatment. Whole-cell, time lapse images are demonstrated to show the ability to transform live cells into dynamic laboratories to monitor temporal and spatial endosomal pH. The versatility of these probes shows promise for future applications relevant to intracellular trafficking and intelligent drug design.

Live immobilised cells as new therapeutics

Abstract Clinical trials have increasingly provided adequate data for the use of live cells in medicinal practice especially in diarrhea, inflammatory bowel disease including Crohn’s disease, reduction of serum cholesterol, prevention of allergies, cancer, and numerous other diseases. Oral delivery of live cells has met with limited success; chiefly due to viability losses on passage through the gastrointestinal tract. Conflicting reports exist on the effectiveness of the protection afforded by traditional immobilization of live cells in gel matrices such as calcium alginate and kappa-carrageenan. An alternative approach, microencapsulation, builds on immobilization technologies by combining enhanced mechanical stability of the capsule membrane with improved mass transport, increased cell loading and greater control of parameters. This review abridges recent developments in the therapeutic use of live cells, addresses the promises and challenges of current immobilization technologies and provides insights into the concept of artificial cells for the effective delivery of therapeutic live cells.

A review of bacteriocinogenic lactic acid bacteria used as bioprotective cultures in fresh meat produced in Argentina

Several lactic acid bacteria (LAB) associated with meat products are important natural bacteriocin producers. Bacteriocins are proteinaceous antagonistic substances that are important in the control of spoilage and pathogenic microorganisms. The use of LAB as bioprotective cultures to extend the shelf life of fresh meat can improve microbial stability and safety in commercial meat preservation. Lactobacillus curvatus CRL705 used as a protective culture in fresh beef is effective in inhibiting Listeria innocua and Brochothrix thermosphacta as well as the indigenous contaminant LAB, retaining its inhibitory effect at low temperatures and having a negligible effect on meat pH. In addition to the hurdle represented by low temperature and vacuum-packaging, the use of live cells of Lb. curvatus CRL705 seems more feasible from an economic point of view – and without legal restrictions – compared to the addition of purified bacteriocins. A description of meat-borne bacteriocins and their application in meat to extend shelf life is discussed.

Completely self-contained cell culture system: From storage to use

In vitro cell culture systems provide researchers the appropriate tools for effectively studying cell growth and differentiation, understanding cellular response to specific environmental stimuli, and elucidating the function of heterologous biological molecules produced from expression systems. All in vitro cell culture systems require a specific culture media formulated to the nutritional and metabolic requirements of the particular cell type to be cultured. However, the complexity of these systems varies depending on the model organism origin of the cells being cultured (e.g., bacteria, plants, yeast or animal). Unlike bacteria and yeast, mammalian cell cultures require sophisticated auxiliary technologies (e.g., controlled gas mixtures and pressure flow systems, specialized facilities and equipment) and careful handling by trained personnel. These complex requirements pose a limitation to transferring cells to and from remote field locations for investigations. Furthermore, this limitation is a technical hurdle in the development of technologies involving use of live cells (e.g., cytosensors). We identified a novel and unrealized feature in the conventional cell culture system that may be exploited to adapt simple existing technologies to form a portable apparatus for storing and growing cells. The approach we describe is a completely self-contained cell culture system that not only will bring down the cost of culturing cells but also will expand cell culture applications in medicine, research, environmental health, and safety.

Adjunct Cultures: Recent Developments and Potential Significance to the Cheese Industry

Several previous reviews have described different ways to enhance the flavor and texture of cheese, including use of live cells and nonviable attenuated cells as adjunct cultures. However, comparisons between viable and nonviable cultures were never discussed in these reviews. In addition, recent publications on adjunct cultures have not been covered in previous reviews. This article will survey the more recent work on adjunct cultures—with particular attention to whether the adjuncts contained viable or nonviable cells—and propose areas where additional research is needed.

Xenotransplantation: Is the Future upon Us?

Over the past decade, the number of solid organ transplant procedures done in the United States each year has increased substantially, from approximately 13,000 in 1988 to 20,000 in 1996.1 Despite the increased availability of these procedures, the number of potential recipients awaiting organ donation has more than tripled since 1988. At the end of 1996, an estimated 50,000 persons were awaiting organ donations.1 This shortage of available human allografts has prompted the development of investigational therapeutic approaches that use animal tissues or organs (xenografts) in human recipients. Xenotransplantation refers to any procedure that involves the use of live cells, tissues, or organs from a nonhuman animal source for transplantation, implantation, or ex vivo perfusion in humans. In the United States, the modern era of xenotransplantation began with the transplantation of chimpanzee kidneys into patients with chronic renal failure.2 It is likely that, in 1964, when this procedure was introduced, it was viewed as one with limited clinical utility and a procedure for the future. However, recent scientific and biomedical advances have made possible more extended use of animal tissues or organs for human clinical applications beyond organ transplantation; animal cells, tissues, or organs have been used for extracorporeal perfusions of patients awaiting organ donation and as a treatment for medical conditions such as Parkinson's disease, diabetes, and human immunodeficiency virus (11W) infection. Although xenotransplantation may be one partial solution to the unmet demand for human organ and tissue donations, its use raises some unique public health concerns, most notably the poten ial for transmission of infections of animal origin (xenozoonoses) to humans.3 In this issue of the Journal, Bone and colleagues have provided an overview of the potential infectious agents and infectious risks associated with use of tissues harvested from pigs, one of the primary species proposed as a source for xenografts.4 While considerable debate has centered around the qu stion of whether one animal source or species may pose a greater risk for xenotransplant-related inf tion than another, the article raises global and provocative questions about the potential infectious isks that may accompany the use of xenotransplantation as a routine therapeutic modality: What is the risk of transmitting endogenous animal pathogens to the human recipient? What is the risk of secondary transmission of xenozoonoses from the recipient to thei contacts (eg, family members, healthcare providers)? Lastly, what risk do xenozoonoses pose to the general population? Currently, the infectious risks posed by xenotransplantation are unknown. However, experience with human allografts has shown that infectious agents (eg, hepatitis B virus, hepatitis C virus, rabies virus, HIV, Candida albicans, and Creutzfeldt-Jakob agent) can be transmitted via transplanted human tissues or organs.5,6 Some investigators have suggested that the ability to produce and use pathogen-free animal sources to obtain clean xenografts would eliminate b th the infectious risks associated with the use

Microbial interactions with caesium—implications for biotechnology

AbstractThe continuing release of caesium isotopes into the environment has highlighted the necessity for efficient removal of Cs from industrial waste effluents prior to discharge. Existing technologies, e.g. zeolite ion‐exchange for Cs removal, can be expensive and microbial metal adsorption/accumulation may represent a cheap alternative. The distinct chemical properties of Cs+, which dictate a high degree of metabolism‐dependent uptake via monovalent cation transport systems, indicate that different approaches are required for biological Cs removal to those which are generally adopted for other metals/radionuclides. The low toxicity of Cs+eliminates one potential problem in the use of live cells for Cs removal. High levels of Cs+accumulation have been reported in a number of microorganisms, but uptake levels vary markedly in different organisms and are strongly influenced by a number of physico‐chemical and mechanical parameters, e.g. the use of batch or continuous‐flow systems, biomass immobilization (which tends to increase Cs+adsorption at the expense of metabolism‐dependent accumulation), pH and particularly the prevalence of other monovalent cations such as K+and Na+. Inherent differences in Cs+uptake capacities of different microorganisms appear to be largely attributable to differences in the affinity of monovalent cation transport systems for Cs+. The application of rigorous screening procedures involving the use of autoradiography has great potential for isolation of microorganisms with particularly high affinities for Cs+. Alternatively, manipulation of the physiological status of microorganisms can dramatically alter the transport of Cs+and other monovalent cations. Hyper‐ and hypo‐osmotic shock, respectively, have so far proved to be the most successful treatments for stimulating Cs removal and recovery. Other manipulations, at both the cellular and molecular level, which are known to influence K+fluxes but have yet to be characterized for Cs+, are outlined here.

Cellular and humoral immune responses in sheep experimentally injected with killed and live corynebacterium pseudotuberculosis

Both humoral and cellular immune responses have been found to be operative in sheep experimentally injected with killed and live Corynebacterium pseudotuberculosis. However, immunity to sonicated C. pseudotuberculosis cells was primarily of humoral nature though cellular response was also noted. In contrast, live C. pseudotuberculosis cells evoked primarily a cellular response and the encountered humoral response was of lesser intensity. Challenge experiment revealed that humoral response alone was insufficient to protect, and the use of live cells to induce cellular response enhanced the immune status of sheep. It was also observed that nonvaccinated sheep in a herd can acquire immunity from their vaccinated counterparts suggesting a certain importance of 'herd immunity' in C. pseudotuberculosis vaccination.