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61.
Spatial distribution of ant workers and, notably their aggregation/segregation behaviour, is a key-element of the colony social
organization contributing to the efficiency of task performance and division of labour. In polymorphic species, specialized
worker castes notably differ in their intrinsic aggregation behaviour. In this context, knowing the preponderant role of minors
in brood care, we investigate how a stimulus such as brood can influence the spatial patterns of Pheidole pallidula worker castes. In a homogeneous area without brood, it was shown that minors display only a low level of aggregation while
majors form large clusters in the central area. Here we find out that these aggregation patterns of both minors and majors
can be deeply influenced by the presence of brood. For minors, it nucleates or enhances the formation of a large stable cluster.
Such high sensitivity of minors to brood stimuli fits well with their role as main brood tenders in the colony. For majors,
interattraction between individuals still remains the prevailing aggregation factor while brood strongly influences the localisation
of their cluster. We discuss how the balance between interattraction and sensitivity to environmental stimuli determines the
mobility of each worker castes and, consequently, the availability of minors and majors to participate in everyday colony
tasks. Moreover, we will evoke the functional value of majors’ cluster location close to the brood, namely with respect to
social regulation of the colony caste ratio.
Received 30 May 2005; revised 11 January 2006; accepted 13 January 2006. 相似文献
62.
Facultative joint colony founding by social insects (pleometrosis) provides an outstanding opportunity to analyze the costs
and benefits of sociality. Pleometrosis has been documented for a range of social insects, but most studies on the adaptive
benefits of this behavior are restricted to the Hymenoptera. In this study, we provide the first analysis of costs and benefits
associated with pleometrosis for Australian Dunatothrips, which form domiciles by glueing together phyllodes (leaves) of their Acacia host plant. In Dunatothrips aneurae, the distribution of foundress numbers per nest indicated that females formed associations non-randomly. Furthermore, average
group size was independent of both the number of foundresses on the host plant and the number of mature colonies, suggesting
that this behavior was not simply a response to limited availability of nesting sites. Although per capita reproduction declined
with increasing group size, we also identified two benefits of pleometrosis: (1) individual foundresses in groups had higher
survival than solitary foundresses during the brood development period, and (2) larger colony sizes resulting from pleometrosis
provided a benefit later in colony development, because a higher proportion of D. aneurae adults survived invasions by the kleptoparasite Xaniothrips mulga when colony size was larger. These results demonstrate that the reproductive costs of pleometrosis are at least partially
counterbalanced by survival benefits.
Received 4 April 2006; revised 9 September 2006; accepted 20 September 2006. 相似文献
63.
Hatchery selection promotes boldness in newly hatched brown trout (Salmo trutta): implications for dominance 总被引:2,自引:0,他引:2
Sundstrom L. Fredrik; Petersson Erik; Hojesjo Johan; Johnsson Jorgen I.; Jarvi Torbjorn 《Behavioral ecology》2004,15(2):192-198
By using newly hatched (approximately 2 weeks old) brown trout(Salmo trutta) from six families of wild and six families ofsea-ranched origin (seventh generation), we tested the hypothesesthat (1) the hatchery environment selects for increased boldness,and (2) boldness predicts dominance status. Sea-ranched troutspend their first 2 years in the hatchery before being releasedinto the wild at the onset of seaward migration. Trout werepresented with a novel object (tack) and with food (brine shrimp),and their responses were measured and scored in terms of boldness.Siblings with increasing difference in boldness were then pairedin dyadic contests. Fish of sea-ranged origin were on averagebolder than were fish of wild origin, and bolder individualswere more likely to become dominant regardless of origin. Boldnesswas not related to RNA levels, indicating that bold behaviorwas not a consequence of higher metabolism or growth rate. Neitherwas size a predictor of bold behavior or the outcome of dyadiccontests. These results are consistent with studies on olderlife stages showing increased boldness toward predators in hatchery-selectedfish, which suggests that behavioral consequences of hatcheryselection are manifested very early in life. The concordancebetween boldness and dominance may suggest that these behaviorsare linked in a risk prone-aggressive phenotype, which may bepromoted by hatchery selection. However, we also found significantvariation in behavioral and growth-related traits among families,suggesting that heritable variation has not been exhausted bysea-ranching procedures. 相似文献
64.
Susan Leekam 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2016,371(1686)
Early psychological theories of autism explained the clinical features of this condition in terms of perceptual and sensory processing impairments. The arrival of domain-specific social cognitive theories changed this focus, postulating a ‘primary’ and specific psychological impairment of social cognition. Across the years, evidence has been growing in support of social cognitive and social attention explanations in autism. However, there has also been evidence for general non-social cognitive impairments in representational understanding, attention allocation and sensory processing. Here, I review recent findings and consider the case for the specificity and primacy of the social cognitive impairment, proposing that we should focus more explicitly on clinically valid features for insights on the integration of ‘social’ and ‘non-social’ cognition. 相似文献
65.
A three-dimensional operational hydrodynamic model, developed at the Institute of Oceanography, University of Gdańsk was used
to forecast hydrological conditions in the Oder Estuary. The model was based on the coastal ocean circulation model known
as the Princeton Ocean Model (POM). Because of wind-driven water backup in the Oder mouth, a simplified operational model
of river discharge, based on water budget in a stream channel, was developed. Linking these two models into a single system
made it possible to forecast water levels, currents, water temperature, and salinity in the estuary. A good fit between the
observed and computed data allowed to consider the model as a reliable environmental tool. Obtaining a hydrological forecast
via a quick website access gives potential users an opportunity to predict the day-by-day course of processes that may affect
different areas of human life and activities, e.g., navigation, port operations, flood protection of coastal areas; the predictions
may also be used in studies of coastal processes in the estuary. 相似文献
66.
67.
D. Padilla F. Acosta J. A. García F. Real Jose R. Vivas 《Archives of microbiology》2009,191(3):191-198
Hafnia alvei, a Gram negative bacillus related to the Enterobacteriaceae family, is considered an opportunistic pathogen of several animal species and humans. In this communication, we describe
fimbrial-like structures from different strains of H. alvei that cannot be easily ascribed to any of the previously reported fimbrial types in this species (type I or type III). Polymerase
chain reaction (PCR) and immunofluorescence assays were carried out to study fimbriae and flagella in H. alvei strains isolated from different sources. No correlation between the results obtained by PCR and those obtained by phenotypic
methods were found, and the antibodies used gave cross or different recognition patterns of the surface structures present
in these strains. We report as well that strain and growth temperature influence fimbriation and expression of flagella in
human and animal isolates of H. alvei. This study also indicates that the absence of fimbriae have a significant positive influence on the initial adhesion of
H. alvei to human epithelial cells. 相似文献
68.
E. Cortés A.A. Kirk J.A. Goolsby P.J. Moran A.E. Racelis M.A. Marcos-García 《Biocontrol Science and Technology》2011,21(11):1369-1373
Arundo donax L. (Poaceae) is native to Mediterranean Europe and invasive in the Rio Grande Basin of North America. Rhizomes from nine sites in France and Spain infested with a candidate control agent, the armoured scale Rhizaspidiotus donacis (Hemiptera: Diaspididae) weighed 50% less than those from nine sites without scale. 相似文献
69.
《Journal of lipid research》2017,58(12):2348-2364
Lipin-1 is a Mg2+-dependent phosphatidic acid phosphatase (PAP) that in mice is necessary for normal glycerolipid biosynthesis, controlling adipocyte metabolism, and adipogenic differentiation. Mice carrying inactivating mutations in the Lpin1 gene display the characteristic features of human familial lipodystrophy. Very little is known about the roles of lipin-1 in human adipocyte physiology. Apparently, fat distribution and weight is normal in humans carrying LPIN1 inactivating mutations, but a detailed analysis of adipose tissue appearance and functions in these patients has not been available so far. In this study, we performed a systematic histopathological, biochemical, and gene expression analysis of adipose tissue biopsies from human patients harboring LPIN1 biallelic inactivating mutations and affected by recurrent episodes of severe rhabdomyolysis. We also explored the adipogenic differentiation potential of human mesenchymal cell populations derived from lipin-1 defective patients. White adipose tissue from human LPIN1 mutant patients displayed a dramatic decrease in lipin-1 protein levels and PAP activity, with a concomitant moderate reduction of adipocyte size. Nevertheless, the adipose tissue develops without obvious histological signs of lipodystrophy and with normal qualitative composition of storage lipids. The increased expression of key adipogenic determinants such as SREBP1, PPARG, and PGC1A shows that specific compensatory phenomena can be activated in vivo in human adipocytes with deficiency of functional lipin-1. 相似文献
70.
Structural-Thermodynamic Relationships of Interactions in the N-Terminal ATP-Binding Domain of Hsp90
Sanjay Nilapwar Eleanor Williams Christosmos Prodromou Mark A. Williams 《Journal of molecular biology》2009,392(4):923-9317
Despite its importance as a target in anti-cancer therapeutics and the numerous rational-based inhibitor design efforts aimed at it, there are only limited data available on structural-thermodynamic relationships of interactions of the N-terminal ATP-binding domain of Hsp90 (N-Hsp90). Here, we redress this by presenting an investigation of binding of nucleotides and ansamycin compounds to this domain. Interactions of nucleotides with N-Hsp90 are relatively weak (> 10 μM) and are strongly enthalpy driven over the temperature range 10-25 °C. Geldanamycin (GA) and its analogues 17-AAG [17-(allylamino)-17-demethoxy-GA] and 17-DMAG (17-N,N-dimethylaminoethylamino-17-demethoxy-GA) bind more strongly and have a dominant favourable enthalpic contribution over the temperature range investigated. We investigated the temperature dependence of the enthalpic contribution to binding. We found that while the ansamycin compounds have the commonly observed negative value, the nucleotides show a negligible or even a positive ΔCp of binding. These data represent the first observation of a single binding site for which interactions with different ligands result in both negative and positive ΔCp values. By addressing the likely impact of the potential contributions from protein-ligand interactions, we are able to attribute the anomalous ΔCp for the nucleotides largely to a change in the conformation of the domain structure and local motion in the lid region of N-Hsp90 with the concomitant exposure of hydrophobic amino acid side chains. 相似文献