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131.
Seppo Rytkönen Laura Kvist Riikka Mikkonen Markku Orell 《Journal of avian biology》2007,38(3):273-277
We asked whether willow tit Parus montanus males adjust their parental care according to their paternity in current brood. The origin of the nestlings was determined by using molecular technique, and the studied broods were assigned into extra-pair paternity (EPP) broods, if at least one nestling was fathered by another male, and truly monogamous broods. Over 3 years, 14 of 40 broods (35%) included EP-offspring, and 29 of 273 nestlings (11%) were EP-young. Intensity of parental care was measured with risk-taking against a potential predator, mounted stoat Mustela erminea . The results showed that risk-taking by EPP males did not differ from that by monogamous males. Neither was the sexual difference in risk-taking different at EPP and monogamous broods. Our results are consistent with the hypothesis that males do not adjust their level of care to paternity, perhaps because they have no reliable cues for assessing their paternity. This may be related to the success of mate-guarding in their breeding environment, closed forests. Guarding is seemingly successful as the EPP levels are rather low, but it is not totally sure making the potential costs, rejection of own young, too high. We also discuss other population characteristics which may further prevent the evolution of paternity assessment in northern willow tits. 相似文献
132.
Riitta Puupponen-Pimiä Markku Saloheimo Tuija Vasara Runar Ra Janka Gaugecz Ulrika Kurtén Jonathan K. C. Knowles Sirkka Keränen Veli Kauppinen 《Plant molecular biology》1993,23(2):423-428
We have isolated the birch homologue (BP8) for the carrot embryogenic gene DC8 by heterologous hybridization. The birch BP8 gene encodes a putative protein of 53 kDa, showing 52% sequence identity with the DC8 gene at the amino acid level. The putative BP8 protein contains 20 repeats of 11 amino acids and thus belongs to the group of LEA proteins isolated from such plants as carrot, cotton and wheat. Northern hybridization of mRNA isolated from birch cells representing different stages of somatic embryogenesis and non-embryogenetic material with a PB8 probe gave no signals, suggesting a low expression level of the BP8 gene. 相似文献
133.
Váradi T Mersich T Auvinen P Tammi R Tammi M Salamon F Besznyák I Jakab F Baranyai Z Sz?ll?si J Nagy P 《The journal of histochemistry and cytochemistry》2012,60(8):567-575
Although trastuzumab is an efficient drug, primary and acquired resistance is a challenging problem. The authors have previously shown in mouse xenograft experiments that masking ErbB2 by hyaluronan leads to diminished binding of the antibody and consequent resistance. In the current work, they correlated trastuzumab binding with the pericellular density of hyaluronan in ErbB2-overexpressing human breast cancer samples. A method for quantifying the relative binding of trastuzumab was developed involving constant and low-frequency background subtraction, segmenting the image to membrane and background pixels followed by evaluation of trastuzumab fluorescence, normalized with the expression level of ErbB2, only in the membrane. The normalized binding of trastuzumab showed a negative correlation with the pericellular density of hyaluronan (r = -0.52) with the effect being the most pronounced in the extreme cases (i.e., low and high hyaluronan densities predicted strong and weak binding of trastuzumab, respectively). Removal of hyaluronan by hyaluronidase digestion unmasked the trastuzumab binding epitope of ErbB2 demonstrated by a significantly increased normalized binding of the antibody. The results show that the accumulation of pericellular hyaluronan plays a crucial role in masking ErbB2. 相似文献
134.
Pasonen-Seppänen S Hyttinen JM Rilla K Jokela T Noble PW Tammi M Tammi R 《Histochemistry and cell biology》2012,137(1):107-120
CD44 is a ubiquitous cell surface glycoprotein, involved in important cellular functions including cell adhesion, migration,
and modulation of signals from cell surface receptors. While most of these CD44 functions are supposed to involve hyaluronan,
relatively little is known about the contribution of CD44 to hyaluronan maintenance and organization on cell surface, and
the role of CD44 in hyaluronan synthesis and catabolism. Blocking hyaluronan binding either by CD44 antibodies, CD44-siRNA
or hyaluronan decasaccharides (but not hexasaccharides) removed most of the hyaluronan from the surfaces of both human (HaCaT)
and mouse keratinocytes, resembling results on cells from CD44−/− animals. In vitro, compromising CD44 function led to reduced
and increased amounts, respectively, of intracellular and culture medium hyaluronan, and specific accumulation below the cells.
In vivo, CD44-deficiency caused no marked differences in hyaluronan staining intensity or localization in the fetal skin or
in adult ear skin, while tail epidermis showed a slight reduction in epidermal hyaluronan staining intensity. However, CD44-deficient
tail skin challenged with retinoic acid or tape stripping revealed diffuse accumulation of hyaluronan in the superficial epidermal
layers, normally negative for hyaluronan. Our data indicate that CD44 retains hyaluronan in the keratinocyte pericellular
matrix, a fact that has not been shown unambiguously before, and that hyaluronan abundance in the absence of CD44 can result
in hyaluronan trapping in abnormal locations possibly interfering there with normal differentiation and epidermal barrier
function. 相似文献
135.
Niederhauser B Siivonen J Määttä JA Jänis J Kulomaa MS Hytönen VP 《Journal of biotechnology》2012,157(1):38-49
Avidins represent an interesting group of proteins showing high structural similarity and ligand-binding properties but low similarity in primary structure. In this study, we show that it is possible to create functional chimeric proteins from the avidin protein family when applying DNA family shuffling to the genes of the avidin protein family: avidin, avidin related gene 2 and biotin-binding protein A. The novel chimeric proteins were selected by phage display biopanning against biotin, and the selected enriched proteins were characterized, displaying diverse features distinct from the parental genes, including binding to cysteine. 相似文献
136.
Merikanto I Kronholm E Peltonen M Laatikainen T Lahti T Partonen T 《Chronobiology international》2012,29(3):311-317
Individuals show variation in their preference for the daily timing of activities. In this study the authors analyzed whether chronotypes associate with sleep duration and sleep-related complaints. The authors used the National FINRISK Study 2007 Survey data on 3696 women and 3162 men, representative of the Finnish population aged 25 yrs and older, for the assessment of chronotype and self-reported sleep. Evening types experienced insomnia symptoms, had nightmares, and had used recently hypnotics significantly more often than other chronotypes among both men and women. In a multinominal logistic regression model predicting insufficient sleep, the association of eveningness with insufficient sleep was not abolished after adjustment for sex, age, and sleep duration. The prevalence of short sleepers was significantly higher in evening types among men than among women, whereas that of long sleepers was significantly higher in evening types among both men and women, as compared with the other chronotypes. These results indicate that eveningness predisposes individuals to a range of sleep complaints. 相似文献
137.
Indoor air pollution resulting from the combustion of solid fuels has been identified as a major health threat in the developing world. This study examines how the choice of cooking fuel, place of cooking and behavioural risk factors affect respiratory health infections in Accra, Ghana. About 65.3% of respondents use charcoal and 4.2% use unprocessed wood. A total of 241 (25.4%) respondents who cook had had respiratory health symptoms in the two weeks preceding the study. Household socioeconomic status and educational attainment of respondents were found to have a significant impact on respiratory health through their particular influence on the choice of cooking fuel. Households that use wood and charcoal have a high incidence of respiratory health symptoms. The poor are more affected by respiratory health problems due to their heavy dependence on solid fuels as compared with their wealthy counterparts. Households that cook in multiple purpose rooms are more affected by respiratory health problems than those that cook outdoors. There is a positive correlation between the presence of children in the kitchen during cooking and the incidence of respiratory health symptoms among children (r=0.31, p<0.0001). Poverty and lack of education and awareness are the major factors affecting the choice of cooking fuel, place of cooking and respiratory health in Accra. 相似文献
138.
Jonna Engström-Öst Miina Karjalainen Markku Viitasalo 《Environmental Biology of Fishes》2006,76(1):109-117
We studied the effect of cyanobacteria on foraging and refuge use in small fish. We measured pike larval feeding in the presence of cyanobacteria by counting leftover prey. Our results showed that feeding by pike larvae on zooplankton prey decreased significantly in the presence of non-toxic cyanobacteria. The behaviour can be due to lowered vision caused by turbidity or clogging of the gills. Further, we tested whether the three-spined stickleback use toxic cyanobacteria as a refuge against predators in a choice experiment. The choice experiment was performed in a Y-maze fluviarum, where the fish could select between two different environments. Our results support the refuge use hypothesis because the three-spined stickleback clearly preferred toxic cyanobacteria to the chemical predator signal. To conclude, cyanobacteria decrease feeding rates in fish larvae, but may function as important refuge for e.g. sticklebacks, during predation pressure in pelagic algal blooms. 相似文献
139.
David L. A. Gaveau Justin Epting Owen Lyne Matthew Linkie Indra Kumara Markku Kanninen Nigel Leader-Williams 《Journal of Biogeography》2009,36(11):2165-2175
Aim This study determines whether the establishment of tropical protected areas (PAs) has led to a reduction in deforestation within their boundaries or whether deforestation has been displaced to adjacent unprotected areas: a process termed neighbourhood leakage.
Location Sumatra, Indonesia.
Methods We processed and analysed 98 corresponding LANDSAT satellite images with a c. 800 m2 resolution to map deforestation from 1990 to 2000 across 440,000 km2 on the main island of Sumatra and the smaller island of Siberut. We compared deforestation rates across three categories of land: (1) within PAs; (2) in adjacent unprotected land lying with 10 km of PA boundaries; and (3) within the wider unprotected landscape. We used the statistical method of propensity score matching to predict the deforestation that would have been observed had there been no PAs and to control for the generally remote locations in which Sumatran PAs were established.
Results During the period 1990–2000 deforestation rates were found to be lower inside PAs than in adjacent unprotected areas or in the wider landscape. Deforestation rates were also found to be lower in adjacent unprotected areas than in the wider landscape.
Main conclusions Sumatran PAs have lower deforestation rates than unprotected areas. Furthermore, a reduction in deforestation rates inside Sumatran PAs has promoted protection, rather than deforestation, in adjacent unprotected land lying within 10 km of PA boundaries. Despite this positive evaluation, deforestation and logging have not halted within the boundaries of Sumatran PAs. Therefore the long-term viability of Sumatran forests remains open to question. 相似文献
Location Sumatra, Indonesia.
Methods We processed and analysed 98 corresponding LANDSAT satellite images with a c. 800 m
Results During the period 1990–2000 deforestation rates were found to be lower inside PAs than in adjacent unprotected areas or in the wider landscape. Deforestation rates were also found to be lower in adjacent unprotected areas than in the wider landscape.
Main conclusions Sumatran PAs have lower deforestation rates than unprotected areas. Furthermore, a reduction in deforestation rates inside Sumatran PAs has promoted protection, rather than deforestation, in adjacent unprotected land lying within 10 km of PA boundaries. Despite this positive evaluation, deforestation and logging have not halted within the boundaries of Sumatran PAs. Therefore the long-term viability of Sumatran forests remains open to question. 相似文献
140.