The fine structure of brown adipose tissue. I. Cold-induced changes in the rat.
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Adaptation, Biological↗
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Medical psychology in exercise and sport.
Several psychological outcomes that accompany acute and chronic exercise have medical significance. Transient reductions in somatic tension and subjective anxiety appear most reliable. Symptom abatement in moderate depression can occur with chronic exercise in a manner comparable to psychotherapy and may offer a better prognosis in some instances. Other cognitive, behavioral, and perceptual events associated with exercise may assist in managing mental health, and exercise has been successfully used as a therapeutic adjunct in a variety of psychiatric disorders. Regular exercise may also complement treatments designed to manage aspects of coronary-prone behavior and psychoendocrine responsivity to mental stress. The lack of strict experimental control or effective placebo contrasts in most exercise studies precludes a convincing argument that exercise causes the psychological outcomes observed. Rather, expectancy of benefits, generalized treatment or attention effects, social reinforcement, and past history or selection bias represent likely alternatives. These competing explanations do not discount, however, that many individuals benefit in a clinically significant way. Exercise offers a low-cost alternative or adjunct with side effects that appear largely health-related. Although the effective psychological dosage or modality has not been quantified, current physiologic guidelines of the American College of Sports Medicine (large muscle rhythmic activity, for 20 to 60 minutes, 3 to 5 days per week at 60 to 80 per cent age-adjusted maximal heart rate), or a weekly caloric cost of 2000 kcal, should be effective with little medical risk. However, no evidence confirms that an increase in metabolic or psychoendocrine tolerance to exercise is necessary or sufficient for psychological outcomes to occur. Although biologic adaptations are known to follow exercise training and subside with diminished activity, there is currently no objective evidence that habitual exercise leads to dependence. If exercise has use in managing subjective or somatic symptoms, these may return during periods of exercise abstinence. Moreover, despite popular hypotheses concerning endorphins and biogenic amines, no direct relationships have yet been shown between exercise-induced mood swings and peripheral biochemical events. A proportion of habitual runners have reported acute episodes of euphoria-like states during or following exercise, but this remains a subjective and unpredictable event that may be related to psychophysiologic relaxation or acute changes in self-esteem.(ABSTRACT TRUNCATED AT 400 WORDS)
Adult↗
Culture of the marine cyanobacterium, Lyngbya majuscula (Oscillatoriaceae), for bioprocess intensified production of cyclic and linear lipopeptides.
Cyanobacteria are an ancient and diverse group of photosynthetic microorganisms, which inhabit many different and extreme environments. This indicates a high degree of biological adaptation, which has enabled these organisms to thrive and compete effectively in nature. The filamentous cyanobacterium, Lyngbya majuscula, produces several promising antifungal and cytotoxic agents, including laxaphycin A and B and curacin A. Samples of L. majuscula collected from Moorea Island, Tahiti (French Polynesia) and from the Culture Collection of Algae and Protozoa (CCAP 1446/4) were studied and adapted to large scale laboratory culture (5 l). This constitutes a 100-fold scale-up for the culture of this particular strain of L. majuscula. The effect of culture vessel configurations, growth conditions and media compositions on growth of L. majuscula was examined. Using optimised culture conditions, two strains of L. majuscula are currently being evaluated for their production of secondary metabolites. Results will be compared with those obtained from four environmental extracts. Comparisons were made by thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). It was shown that varying the culture conditions under which L. majuscula was grown had the greatest effect on secondary metabolite production, thus providing potential for future bioprocess intensified production.
Chromatography, High Pressure Liquid↗
Cellular activity in e-PTFE reconstructed pulleys and adjacent regions of deep flexor tendons. An experimental biochemical study in rabbits.
The biological adaptation and integration of flexor tendon pulleys reconstructed with expanded polytetrafluorethylene (e-PTFE) were investigated 3 months after operation. E-PTFE pulleys showed no signs of failure, adverse tissue reactions or detrimental effects on the surface of underlying tendons. Cells in pulleys reconstructed with e-PTFE synthesized proteoglycan, collagen and non-collagen protein at a higher rate, and DNA at a lower rate, than cells in sham operated pulleys. Cells in pulleys reconstructed with e-PTFE synthesized proteoglycan at a lower rate, and protein at a higher rate, than cells in e-PTFE strips placed subcutaneously. Flexor tendon segments underlying reconstructed or sham operated pulleys synthesized matrix components and DNA at comparable rates.
Adaptation, Physiological↗
Expression of emotion in voice and music.
Vocal communication of emotion is biologically adaptive for socially living species and has therefore evolved in a phylogenetically continuous manner. Human affect bursts or interjections can be considered close parallels to animal affect vocalizations. The development of speech, unique to the human species, has relied on the voice as a carrier signal, and thus emotion effects on the voice become audible during speech. This article reviews (a) the evidence on listeners' ability to accurately identify a speaker's emotion from voice cues alone, (b) the research efforts trying to isolate the acoustic features that determine listener judgments, and (c) the findings on actual acoustic concomitants of a speaker's emotional state (real or portrayed by actors). Finally, based on speculations about the joint origin of speech and vocal music in nonlinguistic affect vocalizations, similarities of emotion expression in speech and music are discussed.
Affect↗
Comparison of biological and physical properties of human and animal A(H1N1) influenza viruses.
The study of biological properties of influenza virus strains belonging to the same subtype A(H1N1) and closely antigenically related, but isolated from different animal species (man, pig and duck), demonstrated that avian strains were more resistant than those isolated from mammals to high temperature and low pH, as shown by titration of residual infectivity in cell cultures (MDCK) and by sialidase assay. The difference in behaviour could be correlated to biological adaptation of the virus to its host. Avian body temperature is 40 degrees C and influenza virus, in ducks, is enterotropic and therefore capable of passing through the low pH values in the upper digestive tract of the animal. These results do not contradict the hypothesis of a possible filiation between avian and mammalian orthomyxoviruses.
Animals↗
[Primary molecular changes and secondary biological problems in Bartter and Gitelman syndrome].
Bartter syndrome and Gitelman syndrome are primary hereditary diseases characterized by hypokaliemia, alkalosis, hypertrophy of the juxtaglomerular complex with secondary hyperaldoteronism and normal blood pressure. They result from molecular disorders leading to a defect of sodium reabsorption in respectively the Henle's loop and the distal convoluted tubule. Biological adaptations of downstream tubular segments, i.e. distal convoluted tubule and collecting duct, are responsible for hypokaliemia, alkalosis, renin-aldosterone activation, prostaglandins hypersecretion and dysregulation of the urinary excretion of calcium and magnesium, illustrating the close integration of the regulation of different solutes in the distal tubular structures.
Bartter Syndrome↗
[Plasticity of the myocardium in pediatric cardiology].
The phenotypic adaptation of the myocardium to mechanical overload is a well known concept. The changes that occur into the myocardial structure in heart failure lead to new therapeutical approaches, particularly the use of ACE inhibitors in the treatment of dilated cardiomyopathies in order to prevent myocardial remodeling. In the hypoplastic left heart syndrome or in pulmonary atresia-intact septum, the pathogenetic process is supposed to be abnormal intra-cardiac blood flow during fetal life inducing abnormal cardiac remodeling. When the left ventricle ejects into the pulmonary circulation (double discordance, atrial repair of transposition of the great arteries), the surgical repair that consists to replace the left ventricule in the systemic circuit is based on the concept of ventricular remodeling and plasticity.
Adaptation, Biological↗
Estrogens, brain and behavior: studies in fundamental neurobiology and observations related to women's health.
Mechanisms and consequences of the effects of estrogen on the brain have been studied both at the fundamental level and with therapeutic applications in mind. Estrogenic hormones binding in particular neurons in a limbic-hypothalamic system and their effects on the electrophysiology and molecular biology of medial hypothalamic neurons were central in establishing the first circuit for a mammalian behavior, the female-typical mating behavior, lordosis. Notably, the ability of estradiol to facilitate transcription from six genes whose products are important for lordosis behavior proved that hormones can turn on genes in specific neurons at specific times, with sensible behavioral consequences. The use of a gene knockout for estrogen receptor alpha (ERalpha) revealed that homozygous mutant females simply would not do lordosis behavior and instead were extremely aggressive, thus identifying a specific gene as essential for a mammalian social behavior. In dramatic contrast, ERbeta knockout females can exhibit normal lordosis behavior. With the understanding, in considerable mechanistic detail, of how the behavior is produced, now we are also studying brain mechanisms for the biologically adaptive influences which constrain reproductive behavior. With respect to cold temperatures and other environmental or metabolic circumstances which are not consistent with successful reproduction, we are interested in thyroid hormone effects in the brain. Competitive relations between two types of transcription factors - thyroid hormone receptors and estrogen receptors have the potential of subserving the blocking effects of inappropriate environmental circumstances on female reproductive behaviors. TRs can compete with ERalpha both for DNA binding to consensus and physiological EREs and for nuclear coactivators. In the presence of both TRs and ERs, in transfection studies, thyroid hormone coadministration can reduce estrogen-stimulated transcription. These competitive relations apparently have behavioral consequences, as thyroid hormones will reduce lordosis, and a TRbeta gene knockout will increase it. In sum, we not only know several genes that participate in the selective control of this sex behavior, but also, for two genes, we know the causal routes. Estrogenic hormones are also the foci of widespread attention for their potential therapeutic effects improving, for example, certain aspects of mood and cognition. The former has an efficient animal analog, demonstrated by the positive effects of estrogen in the Porsolt forced swim test. The latter almost certainly depends upon trophic actions of estrogen on several fundamental features of nerve cell survival and growth. The hypothesis is raised that the synaptic effects of estrogens are secondary to the trophic actions of this type of hormone in the nucleus and nerve cell body.
Affect↗
Cell and molecular biology of the assembly and secretion of apolipoprotein B-containing lipoproteins by the liver.
Triglycerides are one of the most efficient storage forms of free energy. Because of their insolubility in biological fluids, their transport between cells and tissues requires that they be assembled into lipoprotein particles. Genetic disruption of the lipoprotein assembly/secretion pathway leads to several human disorders associated with malnutrition and developmental abnormalities. In contrast, patients displaying inappropriately high rates of lipoprotein production display increased risk for the development of atherosclerotic cardiovascular disease. Insights provided by diverse experimental approaches describe an elegant biological adaptation of basic chemical interactions required to overcome the thermodynamic dilemma of producing a stable emulsion vehicle for the transport and tissue targeting of triglycerides. The mammalian lipoprotein assembly/secretion pathway shows an absolute requirement for: (1) the unique amphipathic protein: apolipoprotein B, in a form that is sufficiently large to assemble a lipoprotein particle containing a neutral lipid core; and, (2) a lipid transfer protein (microsomal triglyceride transfer protein-MTP). In the endoplasmic reticulum apolipoprotein B has two distinct metabolic fates: (1) entrance into the lipoprotein assembly pathway within the lumen of the endoplasmic reticulum; or, (2) degradation in the cytoplasm by the ubiquitin-dependent proteasome. The destiny of apolipoprotein B is determined by the relative availability of individual lipids and level of expression of MTP. The dynamically varied expression of cholesterol-7alpha-hydroxylase indirectly influences the rate of lipid biosynthesis and the assembly and secretion lipoprotein particles by the liver.
Apolipoproteins B↗
A comparison of taste thresholds for sweet and astringent-tasting compounds in great apes.
Taste responses to fructose and tannic acid were compared between great apes using the 'two-bottle test' with tests of brief duration. The taste thresholds for fructose were [10-20] mM in Pongo pygmaeus, [40-50] mM in Pan troglodytes, and [70-80] mM in Gorilla gorilla. Inhibition thresholds for tannic acid were [2.9-3.5] mM in Pongo and [2.9-5.9] mM in Pan. Gorillas apparently significantly preferred tannins at low concentrations ([0.59-5.9] mM) but rejected concentrations above [8.8-14.7] mM. These results are discussed in relation to the effects of phylogenetic inertia and biological adaptation.
Animals↗
When theories of speech meet the real world.
Two theories of speech--one quite conventional, the other much less so--account very differently for the biological advantage of speech over writing/reading. The guiding assumption of the more conventional theory is that the elements of speech are sounds, and that these are served by processes of motor control and auditory perception that are in no way specialized for language. Accordingly, there must be a cognitive stage, beyond action and perception, where the motor and auditory representations are somehow invested with linguistic significance. On the conventional view, then, the sounds of speech are just like the letters of the alphabet. Neither has more than an arbitrary relation to language, hence the difference between them is trivially a matter of which of the equally large gaps between signal and message needs to be bridged. On the less conventional theory, the ultimate constituents of speech are not sounds, but articulatory gestures. Having evolved exclusively in the service of language, they form a natural class, a phonetic modality. Being phonetic to begin with, they do not require to be made so by cognitive translation. And that, very simply, is the advantage of speech over writing/reading. Speech has the corollary advantage that it is managed by a module biologically adapted to circumvent limitations of tongue and ear by automatically coarticulating the constituent gestures and coping with the complex acoustic consequences. But a result is that awareness of phonetic structure is not normally a product of having learned to speak: The module "spells"--that is, sequences phonetic segments--for the speaker and recovers the segments for the listener, leaving both in the dark about the way that is done; the gestural representations are immediately phonetic in nature, precluding the cognitive translation that would bring them to notice; and coarticulation destroys all correspondence in segmentation between acoustic and phonetic structures, making it that much harder to demonstrate the alphabetic nature of speech at the acoustic surface. Accordingly, special difficulty in becoming literate might be caused by a weakness of the phonetic module, for that would produce primary representations of a fragile sort, with the consequence that they would be that much harder to bring to awareness--as is required if they are to serve writers and readers as the units of an alphabetic script--and also that much less able to bear the weight of working memory.
Awareness↗
Physiological, morphological and behavioural adaptation to a sodium deficient environment by wild native Australian and introduced species of animals.
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Adaptation, Biological↗
Divergent selection maintains adaptive differentiation despite high gene flow between sympatric rainbow smelt ecotypes (Osmerus mordax Mitchill).
In this study, we investigate the relative role of historical factors and evolutionary forces in promoting population differentiation in a new case of sympatric dwarf and normal ecotypes of the rainbow smelt (Osmerus mordax Mitchill) in Lac Saint-Jean (Québec, Canada). Our first objective was to test the hypothesis that the evolution of sympatric smelt ecotypes in Lac Saint-Jean has been contingent upon the secondary contact between two evolutionary lineages in postglacial times. Secondly, the QST method was applied to test the null hypothesis that the extent of phenotypic differences relative to that of neutral marker variation would be similar in comparisons involving populations within and among ecotypes. Thirdly, we applied a quantitative-genetic method as an exploratory assessment as to whether the amount of gene flow observed between populations could affect divergence in adaptive traits under specific conditions. This study revealed a unique situation of dwarf and normal smelt ecotypes that are, respectively, characterized by selmiparous and iteroparous life histories and the occurrence in each of two genetically distinct populations that synchronously use the same spawning habitat in two tributaries. Historical contingency has apparently played little role in the origin of these populations. In contrast, an important role of divergent natural selection in driving their phenotypic divergence was suggested. While divergent selection has apparently been strong enough to maintain phenotypic differentiation in the face of migration, this study suggests that gene flow has been sufficiently important to modulate the extent of adaptive differentiation being achieved between ecotypes, unless the extent of stabilizing selection acting on smelt ecotypes is much more pronounced than usually reported in natural populations.
Adaptation, Biological↗
Condylar changes after contralateral mandibular osteotomy in the rabbit.
Following orthognathic surgery undesirable changes in the temporomandibular joints (TMJs) are noted sometimes. Altered stress on the condyle and surrounding tissue frequently causes morphological changes in the TMJ. The purpose of the present study was to assess these morphologic changes in a rabbit following mandibular osteotomy and the resulting mandibular body rotation. Adult male Japanese white rabbits (3 kg, 12-16 weeks old) were applied in this study. An experimental mandibular osteotomy was performed on the right side of the body of the mandible. The surgery includes vertical mandibular body osteotomy 5 mm in width after masseter muscle reflection. Then the anterior and posterior osseous segments were fixed with wire at previously made holes. As a result, the condylar medio-lateral width on the contralateral (left) side was significantly larger than that of the ipsilateral side 2 weeks postoperatively (p < 0.05). There were significant differences in the angle between the right and the left condylar heads 4 weeks postoperatively (p < 0.05). The present experimental study demonstrated morphological changes in the contralateral TMJ caused by unilateral mandibular osteotomy. Postoperative morphological changes implied that there is a process of biological adaptation in the rabbit TMJ.
Adaptation, Physiological↗
[Environment-induced adaptation and lenons of internal organs].
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Adaptation, Biological↗
Metallothionein induction in response to restraint stress. Transcriptional control, adaptation to stress, and role of glucocorticoid.
Metallothioneins (MT) have been implicated in the protection of cells from oxidative stress. We studied the molecular mechanism of induction of MT-I and MT-II in response to restraint stress using a mouse model system in which the animals were restrained in well ventilated polypropylene tubes for 12 h each day (one cycle). Here, we show that MT-I and MT-II mRNA levels were elevated as much as 10-20-fold after just one cycle of this simple stress. Stress-mediated MT induction occurred at the transcriptional level. The level of MT mRNA correlated with the stress-induced increase, and not with the diurnal variation, in the level of serum glucocorticoid. Treatment of the mice with RU 486, a glucocorticoid receptor antagonist, prior to restraint stress inhibited MT induction by at least 50%. Furthermore, the glucocorticoid responsive element-binding activity in the liver nuclear extracts from the stressed mice was significantly higher than that in the control mice. The complex formations between the transcription factor Sp1, MTF1, or MLTF/ARE and the respective specific oligonucleotides were not altered in the liver from the stressed mouse. The MT mRNA levels returned to the basal level at the end of nine cycles of stress, indicating habituation of the animals to restraint stress. At this stage, exposure of the animals to another type of stress, treatment with heavy metals, resulted in further induction of MT. These data indicate that glucocorticoid is the primary physiological factor responsible for MT induction following restraint stress, and the glucocorticoid receptor is the major transcription factor involved in this process.
Adaptation, Biological↗
Promotive medicine and the phenomenon of health.
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Adaptation, Biological↗