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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Erwinia aroideae carries a cryptic plasmid with 30 S sedimentation coefficient. Plasmid F'ColVColBtrpcys does not dissociate in E. aroideae and is replicated under stringent control since the number of plasmid copies per chromosome does not exceed one. The behaviour of F'ColVColBtrpcys plasmid in E. aroideae is characterized by (1) instability observed at both spontaneous and after EB treatment, (2) depression of plasmid genes that determine colicin synthesis.
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PMID:[F'ColVColBtrpcys plasmid in Erwinia aroideae]. 34 44

Ethological strategies for defence in animals and humans are expressed as either aggression or flight behaviour. Aggression is employed by animals during intraspecific competition for resources, mate, territory and acquiring and maintaining social status. It also disperses individuals throughout the biotope. Flight behaviour is used to avoid a source of danger or harm, has both dynamic arid static forms, is phylogenetically very old and takes precedence over all other activities including social behaviour. Animals exposed to inescapable threats or attacks exhibit a characteristic defensive strategy, arrested flight, which consists of gaze-avoidance or cut-offs, cryptic postures such as immobility and covert surveillance of their surroundings. Arrested flight also occurs in social encounters when submission fails to reduce attacks, and in prey animals when escape from a predator is hampered. Ethological studies show that during interviews, depressed patients exhibit a pattern of non-verbal behaviour having all the hallmarks of arrested flight. Cut-off behaviour, which seeks to reduce the input of flight-evoking stimuli is especially evident in these patients but takes an extreme form, i.e. eye closure, in the gaze-profiles of paranoid patients. It is proposed that cut-offs always denote the presence of incipient flight and that arrested flight is a 'last measure' defensive strategy in response to inescapable proximal threat. It can arise in humans whenever their escape routes are hampered and characterizes the behaviour of patients suffering from depression. As in animals, different pathways may lead to arrested flight in humans. In humans, defensive mechanisms also operate at the mental level through putative ego defences, the psychological function of which is to preserve self-esteem by hindering the access of disturbing emotional material into awareness. It is suggested that they function ethologically as mental cut-offs analogous to the behavioural cut-offs in animals.
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PMID:Ethological strategies for defence in animals and humans: their role in some psychiatric disorders. 987 54

Offspring of close relatives often suffer severe fitness consequences. Previous studies have demonstrated that females, when given a choice, will choose to avoid mating with closely related males. But where opportunities for mate choice are limited or kin recognition is absent, precopulatory mechanisms may not work. In this case, either sex could reduce the risks of inbreeding through mechanisms that occur during or after copulation. During mating, males or females could commit fewer gametes when mating with a close relative. After mating, females could offset the effects of mating with a closely related male through cryptic choice. Few prior studies of sperm competition have examined the effect of genetic similarity, however, and what studies do exist have yielded equivocal results. In an effort to resolve this issue, we measured the outcome of sperm competition when female Drosophila melanogaster were mated to males of four different degrees of genetic relatedness and then to a standardized competitor. We provide the strongest evidence to date that sperm competitive ability is negatively correlated with relatedness, even after controlling for inbreeding depression.
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PMID:Sperm competitive ability and genetic relatedness in Drosophila melanogaster: similarity breeds contempt. 1238 23

Polyploidy in angiosperms is frequently associated with an increase in self-compatibility. Self-fertilization can enhance polyploid establishment, and theory predicts reduced inbreeding depression in polyploids relative to diploids. Therefore, we may expect mating systems that promote self-fertilization or mixed-mating in polyploid species. However, few studies have measured polyploid mating systems and inbreeding depression. We report the outcrossing rate and inbreeding depression for Campanula americana, a self-compatible protandrous herb. Allozyme genotypes suggest that C. americana is an autotetraploid with tetrasomic inheritance. We found that the multilocus outcrossing rate, t(m)=0.938, did not differ from unity. This result was unexpected since previous work demonstrated that pollinators frequently move from male- to female-phase flowers on the same plant, that is, geitonogamy. Self and outcross pollinations were conducted for three populations. Offspring were germinated in controlled conditions and grown to maturity in pots in nature. Inbreeding depression was not significant for most seed and germination characters. However, all later life traits except flowering date differed between inbred and outcrossed individuals resulting in a 26% reduction in cumulative fitness for inbred plants. Limited early- and moderate later-life inbreeding depression suggest that it is buffered by the higher levels of heterozygosity found in an autotetraploid. C. americana appears to have a flexible mating system where within flower protandry and/or cryptic self-incompatibility result in a high outcrossing rate when pollinators are abundant, but self-compatibility and limited inbreeding depression maintain reproductive success when mates are limited.
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PMID:Outcrossing rate and inbreeding depression in the herbaceous autotetraploid, Campanula americana. 1269 84

Natural populations carry deleterious recessive alleles which cause inbreeding depression. We compared mortality and growth of inbred and outbred zebrafish, Danio rerio, between 6 and 48 days of age. Grandparents of the studied fish were caught in the wild. Inbred fish were generated by brother-sister mating. Mortality was 9% in outbred fish, and 42% in inbred fish, which implies at least 3.6 lethal equivalents of deleterious recessive alleles per zygote. There was no significant inbreeding depression in the growth, perhaps because the surviving inbred fish lived under less crowded conditions. In contrast to alleles that cause embryonic and early larval mortality in the same population, alleles responsible for late larval and early juvenile mortality did not result in any gross morphological abnormalities. Thus, deleterious recessive alleles that segregate in a wild zebrafish population belong to two sharply distinct classes: early-acting, morphologically overt, unconditional lethals; and later-acting, morphologically cryptic, and presumably milder alleles.
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PMID:Two classes of deleterious recessive alleles in a natural population of zebrafish, Danio rerio. 1545 92

Inbreeding depression is most pronounced for traits closely associated with fitness. The traditional explanation is that natural selection eliminates deleterious mutations with additive or dominant effects more effectively than recessive mutations, leading to directional dominance for traits subject to strong directional selection. Here we report the unexpected finding that, in the butterfly Bicyclus anynana, male sterility contributes disproportionately to inbreeding depression for fitness (complete sterility in about half the sons from brother-sister matings), while female fertility is insensitive to inbreeding. The contrast between the sexes for functionally equivalent traits is inconsistent with standard selection arguments, and suggests that trait-specific developmental properties and cryptic selection play crucial roles in shaping genetic architecture. There is evidence that spermatogenesis is less developmentally stable than oogenesis, though the unusually high male fertility load in B. anynana additionally suggests the operation of complex selection maintaining male sterility recessives. Analysis of the precise causes of inbreeding depression will be needed to generate a model that reliably explains variation in directional dominance and reconciles the gap between observed and expected genetic loads carried by populations. This challenging evolutionary puzzle should stimulate work on the occurrence and causes of sex differences in fertility load.
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PMID:Inbreeding uncovers fundamental differences in the genetic load affecting male and female fertility in a butterfly. 1587 68

The widespread occurrence of free-ranging domestic or feral carnivores (dogs, cats) or ungulates (pigs, goats), and massive releases of captive-reproduced game stocks (galliforms, waterfowl) is raising fear that introgressive hybridization with wild populations might disrupt local adaptations, leading to population decline and loss of biodiversity. Detecting introgression through hybridization is problematic if the parental populations cannot be sampled (unlike in classical stable hybrid zones), or if hybridization is sporadic. However, the use of hypervariable DNA markers (microsatellites) and new statistical methods (Bayesian models), have dramatically improved the assessment of cryptic population structure, admixture analyses and individual assignment testing. In this paper, I summarize results of projects aimed to identify occurrence and extent of introgressive hybridization in European populations of wolves (Canis lupus), wildcats (Felis silvestris), rock partridges and red-legged partridges (Alectoris graeca and Alectoris rufa), using genetic methods. Results indicate that introgressive hybridization can be locally pervasive, and that conservation plans should be implemented to preserve the integrity of the gene pools of wild populations. Population genetic methods can be fruitfully used to identify introgressed individuals and hybridizing populations, providing data which allow evaluating risks of outbreeding depression. The diffusion in the wild of invasive feral animals, and massive restocking with captive-reproduced game species, should be carefully controlled to avoid loss of genetic diversity and disruption of local adaptations.
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PMID:Detecting hybridization between wild species and their domesticated relatives. 1817 2

The effects of inbreeding on sperm quantity and quality are among the most dramatic examples of inbreeding depression. The extent to which inbreeding depression results in decreased fertilization success of a male's sperm, however, remains largely unknown. This task is made more difficult by the fact that other factors, such as cryptic female choice, male sperm allocation and mating order, can also drive patterns of paternity. Here, we use artificial insemination to eliminate these extraneous sources of variation and to measure the effects of inbreeding on the competitiveness of a male's sperm. We simultaneously inseminated female guppies (Poecilia reticulata) with equal amounts of sperm from an outbred (f = 0) male and either a highly (f = 0.59) or a moderately inbred (f = 0.25) male. Highly inbred males sired significantly fewer offspring than outbred males, but share of paternity did not differ between moderately inbred and outbred males. These findings therefore confirm that severe inbreeding can impair the competitiveness of sperm, but suggest that in the focal population inbreeding at order of a brother-sister mating does not reduce a male's sperm competitiveness.
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PMID:Experimental evidence that high levels of inbreeding depress sperm competitiveness. 1934 80

How might the psycho-social effects of chronic skin disease, its treatments (and discontents) be figuratively expressed in writing and painting? Does the art reveal common denominators in experience and representation? If so, how do we understand the cryptic language of these expressions? By examining the works of artists with chronic skin diseases--John Updike, Elizabeth Bishop, and Zelda Fitzgerald--some common features can be noted. Chronically broken skin can fracture the ego or self-perception, resulting in a disturbed body image, which leads to personality disorders and co-morbid affective disorders such as anxiety and depression. The vertiginous feeling that results can be noted in the paradoxical characters, figures, and psyches portrayed in the works of these artists. This essay will examine the more specific ways in which artists disclose and/or conceal their experiences and the particular ways in which these manifest in their works. While certain nuances exist, the common denominators give us a starting point for developing an eczema aesthetic, a code for interpreting the ways in which artists' experiences with skin disease manifest in their works.
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PMID:Drawing the eczema aesthetic: the psychological effects of chronic skin disease as depicted in the works of John Updike, Elizabeth Bishop, and Zelda Fitzgerald. 2018 66

Mating between close relatives generally results in offspring of decreased fitness. Inbreeding depression is generally greater for life-history traits than for morphological traits, and recent studies of traits subject to sexual selection suggest that these may suffer the greatest inbreeding depression. Sexual selection continues after mating in the form of sperm competition and cryptic female choice, imposing strong selection on male competitive fertilization success. Here, I examine the effects of a single generation of full-sib mating on competitive fertilization success in a cricket, Teleogryllus oceanicus. The estimated coefficient of inbreeding depression in competitive fertilization success was 0.37, higher than that for other life-history and morphological traits. Such intense inbreeding depression coupled with little or no additive genetic variance for this trait is consistent with strong directional selection on male competitive fertilization success generating high levels of dominance variance, and provides an adaptive explanation for the evolution of inbreeding avoidance found in this species.
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PMID:Inbreeding depression in the competitive fertilization success of male crickets. 2109 74


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