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One Host (one + host)
Terms modified by One Host Selected AbstractsReliable high-throughput screening with Pichia pastoris by limiting yeast cell death phenomenaFEMS YEAST RESEARCH, Issue 2 2004Roland Weis Abstract Comparative screening of gene expression libraries employing the potent industrial host Pichia pastoris for improving recombinant eukaryotic enzymes by protein engineering was an unsolved task. We simplified the protocol for protein expression by P. pastoris and scaled it down to 0.5-ml cultures. Optimising standard growth conditions and procedures, programmed cell death and necrosis of P. pastoris in microscale cultures were diminished. Uniform cell growth in 96-deep-well plates now allows for high-throughput protein expression and screening for improved enzyme variants. Furthermore, the change from one host for protein engineering to another host for enzyme production becomes dispensable, and this accelerates the protein breeding cycles and makes predictions for large-scale production more accurate. [source] Factors influencing the evolution of clutch size in a gregarious insect parasitoidJOURNAL OF ANIMAL ECOLOGY, Issue 6 2000Tania Zaviezo Summary 1.,In this study we examined the clutch size of Hyssopus pallidus (Askew) (Hymenoptera, Eulophidae), a gregarious ectoparasitoid of codling moth (Lepidoptera, Tortricidae) larvae that is characterized by a host handling time of 2 days approximately. 2.,Clutch size increased asymptotically with host larval size (fresh weight) to a maximum of 32 eggs. A single male developed from each clutch, brood survival was 83% and pupal size of female offspring was 0·45 mg, all independent of clutch size. 3.,A comparison of the response of both experienced and naïve adult parasitoids to varying host larval size, indicated that experience was not necessary for H. pallidus to be able to accurately estimate host size. 4.,Clutch size increased by 50% for medium size host larvae (30,40 mg) and 83% for large host larvae (60,76 mg) when the encounter rate was reduced from one host every second day to one every seventh day. A significantly lower clutch size was produced on the last day at the highest encounter rate for large host larvae, suggesting exhaustion of the egg supply for H. pallidus. 5.,Manipulation of parasitoid clutch size on constant size host larvae did not influence sex ratio (single male) or brood survival (93%), but produced a linear trade-off between clutch size and the size (fresh weight) of female pupae. Longevity, lifetime fecundity, total number of hosts attacked, and clutch size all increased linearly with the adult size (female pupal weight). 6.,The observed clutch size in newly emerged H. pallidus is consistent with a strategy of maximizing lifetime fitness gain rather than the gain from individual hosts (Lack clutch size) despite a significant investment in the time required to attack each host. [source] Resource specialization in a phytophagous insect: no evidence for genetically based performance trade-offs across hosts in the field or laboratoryJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2009S. J. AGOSTA Abstract We present a field test of the genetically based performance trade-off hypothesis for resource specialization in a population of the moth Rothschildia lebeau whose larvae primarily feed on three host plant species. Pairwise correlations between growth vs. growth, survival vs. survival and growth vs. survival across the different hosts were calculated, using families (sibships) as the units of analysis. Of 15 pairwise correlations, 14 were positive, 5 significantly so and none were negative. The same pattern was found using complementary growth and survival data from the laboratory. Overall, we found no evidence of negative genetic correlations in cross-host performance that would be indicative of performance trade-offs in this population. Rather, variation among families in performance appears to reflect ,general vigour' whereby families that perform well on one host perform well across multiple hosts. We discuss the implications of positive genetic correlations in cross-host performance in terms of the ecology and evolution of host range. We argue that this genetic architecture facilitates colonization of novel hosts and recolonization of historical hosts, therefore contributing to host shifts, host range expansions, biological invasions and introductions, and host ranges that are regionally broad but locally narrow. [source] The use of ribotyping and antibiotic resistance patterns for identification of host sources of Escherichia coli strainsLETTERS IN APPLIED MICROBIOLOGY, Issue 1 2005M. Samadpour Abstract Aims:, To compare antibiotic resistance and ribotyping patterns ability to identify triplicate isolates sent from a group of 40 Escherichia coli taken from seven host sources. Methods and Results:, Of the 120 isolates, 22 isolates were resistant to ampicillin, streptomycin, tetracycline and trimethoprim and 98 isolates were susceptible. Antibiotic patterns identified 33 of the triplicates and three of the six groups had isolates from multiple hosts. Ribotyping divided the isolates into 27 ribotype groups with all triplicates grouped into the same ribotype group with one host per group. Conclusions:, Antibiotic susceptibility pattern placed 98 of the isolates in a single group with 50% of the antibiotic susceptibility pattern groups containing multiple host species. Ribotyping groups were host specific with each host having one to seven ribotype groups. Significance and Impact of the Study:, Antibiotic susceptibility pattern groups have been used for environmental source identification and faecal pollution tracking, however these groups do not always distinguish between host species. Stability of the markers is a potential concern and this system can only be used if antibiotic resistance levels are high in the isolates studied. All isolates have a ribotype group which was stable and like other molecular methods has advantages over antibiotic susceptibility pattern groups which uses a phenotypic method. [source] Stress response pathways in protozoan parasitesCELLULAR MICROBIOLOGY, Issue 12 2008Nathalie Vonlaufen Summary Diseases caused by protozoan parasites have a dramatic impact on world health. Emerging drug resistance and a general lack of experimental understanding has created a void in the medicine cabinet used to treat these widespread infections. A novel therapeutic idea that is receiving more attention is centred on targeting the microbe's response to the multitude of environmental stresses it encounters. Protozoan pathogens have complex life cycles, often having to transition from one host to another, or survive in a cyst form in the environment until a new host arrives. The need to respond to environmental cues and stress, and endure in less than optimal conditions, is paramount to their viability and successful progression through their life cycle. This review summarizes the research on parasitic stress responses for Apicomplexa, kinetoplastids and anaerobic protozoa, with an eye towards how these processes may be exploited therapeutically. [source] | ||||||||||