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661.
J. Barry Wright J. W. Costerton W. F. McCoy 《Journal of industrial microbiology & biotechnology》1988,3(3):139-146
Summary The growth of two strains ofPseudomonas aeruginosa in stirred batch cultures was monitored by optical density, DNA concentration, and acridine orange direct cell count measurements. Growth of adherent bacteria in pure culture was also observed on suspended glass discs by light and scanning electron microscopy. Strain MUCOID produced significant numbers of filamentous cells in broth culture and in the adherent population, while strain PAO 381 did not produce elongated cells. Filamentous growth of MUCOID could be prevented by the addition of 5 × 10–2 M Mg2+. However, the addition of 0.66 mM EDTA caused an increased proportion of the population (>50%) of MUCOID cells to become filamentous in broth culture. The results are discussed and related to theories regarding bacterial plasticity, and filamentation of normally bacillary cells. 相似文献
662.
Tissue engineering approaches to developing functional substitutes are often highly complex, multivariate systems where many aspects of the biomaterials, bio‐regulatory factors or cell sources may be controlled in an effort to enhance tissue formation. Furthermore, success is based on multiple performance criteria reflecting both the quantity and quality of the tissue produced. Managing the trade‐offs between different performance criteria is a challenge. A “windows of operation” tool that graphically represents feasible operating spaces to achieve user‐defined levels of performance has previously been described by researchers in the bio‐processing industry. This paper demonstrates the value of “windows of operation” to the tissue engineering field using a perfusion‐scaffold bioreactor system as a case study. In our laboratory, perfusion bioreactor systems are utilized in the context of bone tissue engineering to enhance the osteogenic differentiation of cell‐seeded scaffolds. A key challenge of such perfusion bioreactor systems is to maximize the induction of osteogenesis but minimize cell detachment from the scaffold. Two key operating variables that influence these performance criteria are the mean scaffold pore size and flow‐rate. Using cyclooxygenase‐2 and osteopontin gene expression levels as surrogate indicators of osteogenesis, we employed the “windows of operation” methodology to rapidly identify feasible operating ranges for the mean scaffold pore size and flow‐rate that achieved user‐defined levels of performance for cell detachment and differentiation. Incorporation of such tools into the tissue engineer's armory will hopefully yield a greater understanding of the highly complex systems used and help aid decision making in future translation of products from the bench top to the market place. Biotechnol. Bioeng. 2012; 109: 3161–3171. © 2012 Wiley Periodicals, Inc. 相似文献
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An enzyme-linked lectin assay (ELLA) has been developed to detect specific carbohydrate units on the surface of unfixed cells. The assay may be read in standard ELISA plate readers, since the cell-bound enzyme-lectin conjugate is specifically eluted from the cells prior to development of the conjugate. ELLA, when read in an enzyme-linked immunosorbent assay (ELISA) plate reader, allows better detection and relative quantitation of specific surface carbohydrate units than is possible by standard immunofluorescence with fluorescein-conjugated lectins. 相似文献
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Stephen P. Wraight Daniel Molloy Hugo Jamnback Patricia McCoy 《Journal of invertebrate pathology》1981,38(1):78-87
Laboratory trials of Bacillus thuringiensis var. israelensis (serotype 14) and B. sphaericus strain 1593 against field-collected Aedes stimulans showed that susceptibility declined with increasing instar and decreasing temperature. Test results with B. sphaericus were more erratic than with B. thuringiensis, and the efficacy of the former declined more rapidly with decreasing temperature. B. thuringiensis was significantly more active than B. sphaericus under all treatment conditions. These results indicate that the effective use of this strain of B. sphaericus as a mosquito biological control agent may be limited to warm water situations against more susceptible species. 相似文献
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Adrian J. Wolstenholme Mary J. Maclean Ruby Coates Ciaran J. McCoy Barbara J. Reaves 《Invertebrate neuroscience : IN》2016,16(3):7
The macrocyclic lactones (MLs) are one of the few classes of drug used in the control of the human filarial infections, onchocerciasis and lymphatic filariasis, and the only one used to prevent heartworm disease in dogs and cats. Despite their importance in preventing filarial diseases, the way in which the MLs work against these parasites is unclear. In vitro measurements of nematode motility have revealed a large discrepancy between the maximum plasma concentrations achieved after drug administration and the amounts required to paralyze worms. Recent evidence has shed new light on the likely functions of the ML target, glutamate-gated chloride channels, in filarial nematodes and supports the hypothesis that the rapid clearance of microfilariae that follows treatment involves the host immune system. 相似文献