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161.
162.
Jip J. C. Ramakers Phillip Gienapp Marcel E. Visser 《Evolution; international journal of organic evolution》2019,73(2):175-187
Phenotypic plasticity is an important mechanism for populations to respond to fluctuating environments, yet may be insufficient to adapt to a directionally changing environment. To study whether plasticity can evolve under current climate change, we quantified selection and genetic variation in both the elevation (RNE) and slope (RNS) of the breeding time reaction norm in a long‐term (1973–2016) study population of great tits (Parus major). The optimal RNE (the caterpillar biomass peak date regressed against the temperature used as cue by great tits) changed over time, whereas the optimal RNS did not. Concordantly, we found strong directional selection on RNE, but not RNS, of egg‐laying date in the second third of the study period; this selection subsequently waned, potentially due to increased between‐year variability in optimal laying dates. We found individual and additive genetic variation in RNE but, contrary to previous studies on our population, not in RNS. The predicted and observed evolutionary change in RNE was, however, marginal, due to low heritability and the sex limitation of laying date. We conclude that adaptation to climate change can only occur via micro‐evolution of RNE, but this will necessarily be slow and potentially hampered by increased variability in phenotypic optima. 相似文献
163.
Systematic Parasitology - Four new monorchiid trematodes are reported from Moreton Bay, Australia; three new species of Provitellus Dove & Cribb, 1998 and one species of Ovipusillus Dove... 相似文献
164.
González Pamela Dettleff Phillip Valenzuela Cristián Estrada Juan Manuel Valdés Juan Antonio Meneses Claudio Molina Alfredo 《Molecular biology reports》2019,46(6):5875-5882
Molecular Biology Reports - The red cusk-eel (Genypterus chilensis) is a native Chilean species with a high-value market, with the potential to diversify Chilean aquaculture. The objective of this... 相似文献
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We investigated the acceptance of different sized host models by Trichogramma australicum in the laboratory. We used isoline cultures of T. australicum reared in hosts of different sizes. Helicoverpa armigera represent relatively large hosts, and those of Sitotroga cerealella are small, termed the Ha and Sc biotypes, respectively. Five sizes of glass beads were tested for acceptance: diameter 0.5, 0.75, 1.0, 1.5 and 2.0 mm. The acceptance of a host model was determined by persistent attempted drilling of a glass bead by a female. The relationship between host egg size and number of eggs laid by a female was also investigated. We used three sizes of artificial egg (diameter 0.75, 1.00, and 1.50 mm of hemispherical cupules) each containing artificial diet. Ha biotype wasps accepted host models in the range 0.75--1.50 mm dia. (vol. 0.166--1.325 l), whereas those of the Sc biotype accepted host models in the range 0.50--1.00 mm dia. (vol. 0.05--0.393 l). This evidence suggests a lineal (possibly genetic) influence to host size acceptance for T. australicum, dependent on the size of the host in which the wasp has been reared. Also T. australicum lay fewer eggs in smaller artificial eggs than in larger ones. The role of host size in host acceptance and number of eggs delivered, and its implications, is discussed. 相似文献
169.
Fas-ligand-mediated lysis of erbB-2-expressing tumour cells by redirected cytotoxic T lymphocytes 总被引:1,自引:0,他引:1
Haynes NM Smyth MJ Kershaw MH Trapani JA Darcy PK 《Cancer immunology, immunotherapy : CII》1999,47(5):278-286
A chimeric receptor, consisting of the single-chain variable (scFv) domains of an anti-erbB-2 mAb linked via a CD8 membrane-proximal
hinge to the Fc receptor γ chain, was expressed in the mouse cytotoxic T lymphocyte (CTL) hybridoma cell line, MD45. This
cell line was grafted with the additional specificity to recognise and bind erbB-2-expressing breast carcinoma target cells
T47D, MCF-7 and BT-20 in a non-MHC-restricted manner. Tumour cell lysis was antigen-specific since erbB-2-negative tumours
were insensitive to lysis by MD45-scFv-anti-erbB-2-γ clones, and lysis of erbB-2+ tumour targets was inhibited in the presence of an anti-erbB-2 mAb. Furthermore, target cell death correlated with the level
of chimeric receptor expression on the effector MD45 subclones. Redirected MD45 CTL utilised Fas ligand to induce target cell
death since soluble Fas-Fc fusion protein completely inhibited cytolysis. The sensitivity of tumour target cells to Fas ligand
was further enhanced by treating them with interferon-γ, a regulator of Fas and downstream signalling components of the Fas
pathway. Overall, this study has demonstrated the requirement for successful activation of Fas ligand function in conjunction
with cytokine treatment for effective lysis of breast carcinoma target cells mediated by redirected CTL.
Received: 23 July 1998 / Accepted: 5 October 1998 相似文献
170.
Sherry C. Manickchand-Heileman Dawn A.T. Phillip 《Environmental Biology of Fishes》1999,55(4):413-421
Reproduction and growth of the vermilion snapper, Rhomboplites aurorubens, were studied in Trinidad and Tobago. The smallest individual caught measured 145mm total length (TL) and all fish appeared to be mature. It was not possible to precisely determine size at first maturity due to the use of macroscopic techniques. The smallest spent male and female measured 181 and 211mm TL respectively, suggesting a size at first maturity below these sizes. Spawning occurred throughout the year, with a period of peak spawning from about June to November in the rainy season when river runoff increased. Sagittal otolith sections were used for age determination and the opaque ring, which was counted as the annulus, was deposited from January to May in the dry season. A total of 11 age groups between the ages of 2–12 years (155–505mm total length) were found. The von Bertalanffy growth parameters were: L=532mm, K=0.13y–1, and t0=–0.17, where L is the asymptotic length, K is the growth coefficient and t0 is the theoretical age at zero length. The relationship between weight (WT) and length (TL) was WT=3.43×10–5 TL2.82. Vermilion snapper in this study area appears to grow slower and attain a smaller asymptotic length, but has a longer lifespan than found in populations in higher latitudes. This may be attributed to different levels of exploitation, which may be higher in the latter areas. 相似文献