For terrestrial migrants, feeding at migratory stopover sites is important, with prey quality linked to future survival and reproductive success. In contrast, the importance of this behaviour to ...marine species is unknown. The humpback whale Megaptera novaeangliae is a marine migrant that is thought to fast while migrating; however, recent studies suggest that feeding may occur during this time. The aims of this study were to determine how the prey type available on a migratory route off Eden, New South Wales, Australia, influenced whether whales fed or not, and to study the fine-scale behaviour of the whales. Digital acoustic recording tags (DTAGs) and focal follows were used to record whale behaviour. A larger proportion of groups were determined to be feeding when krill was observed at the surface. Whales encountering fish spent a small percentage (28%) of time feeding, behaving similarly to non-feeding whales on migration, with small groups, a higher proportion of males sampled, and relatively straight tracks. In contrast, whales encountering surface swarms of krill spent significantly more time feeding (92%) and behaved similarly to whales on feeding grounds, with larger groups, more females sampled, and tracks with high turning angles. Therefore, changes in the available prey type influenced the amount of time spent feeding and the social dynamics of groups. Given the link between the amount of feeding completed on migration and the future survival and reproductive success of individuals in terrestrial species, the impact of such fluctuations on marine species such as the humpback whale deserves more attention.
Liu J, Li B, Shnider R.
Effects of tai chi training on improving physical function in patients with coronary heart diseases.
J Exerc Sci Fit 2010; 8: 78–84.
Wu G, Keyes L, Callas P, Ren X, Bookchin B.
Comparison of telecommunication, community, and home‐based tai chi exercise programs on compliance and effectiveness in elders at risk for falls.
Arch Phys ...Med Rehabil 2010; 91: 849–56.
The accumulation of oxidized proteins in cells and tissues is a feature of a number of age-related diseases and may also occur as a result of the aging process itself. In this article we review ...recent advances in our understanding of the cellular degradation of oxidized proteins directing our attention primarily to information which directly bears on the behavior of intact eukaryotic cells. We summarize new work on the key intracellular degradative machineries, proteasomes and lysosomes and examine evidence implicating an increase in protein hydrophobicity as the primary signal to the proteasome to initiate degradation. The data identifying the proteasome as the main route of degradation of oxidized proteins is examined, as well as recent data investigating changes in proteasome function after exposure of cells to oxidants and the altered catabolism of oxidized proteins in aging cells. Evidence for the cooperation between the lysosomal and proteasomal systems in the degradation of oxidized proteins is discussed. We conclude that the cellular catabolism of oxidized proteins may be a more complex process than it first appeared and suggest key issues that need to be resolved to improve our understanding of this important process.
Protein-bound 3,4-dihydroxyphenylalanine (PB-DOPA) is a major product of hydroxyl radical attack on tyrosine residues of proteins. Levels of PB-DOPA in cells and tissues have been shown to be greatly ...elevated in age-related diseases. We demonstrate for the first time that
l-DOPA (levodopa) can be biosynthetically incorporated into cell proteins by human cells (THP-1 monocytes and monocyte-derived macrophages). The DOPA-containing proteins generated were selectively visualized on PVDF membranes using a redox-cycling staining method. Many cell proteins contained DOPA and seemed to be synthesized as their full-length forms. The cellular removal of DOPA-containing proteins by THP-1 cells was by proteolysis involving both the proteasomal and the lysosomal systems. The rate of cellular proteolysis of DOPA-containing proteins increased at lower levels of DOPA incorporation but decreased at higher levels of DOPA incorporation. The decreased rate of degradation was accompanied by an increase in the activity of cathepsins B and L but the activity of cathepsin S increased only at lower levels of DOPA incorporation. These data raise the possibility that PB-DOPA could be generated in vivo from
l-DOPA, which is the most widely used treatment for Parkinson disease.
In a literature survey, Chernoff et al. (
2017
) dismissed the hypothesis that chronic exposure to β-
N
-methylamino-L-alanine (BMAA) may be a risk factor for progressive neurodegenerative disease. ...They question the growing scientific literature that suggests the following: (1) BMAA exposure causes ALS/PDC among the indigenous Chamorro people of Guam; (2) Guamanian ALS/PDC shares clinical and neuropathological features with Alzheimer’s disease, Parkinson’s disease, and ALS; (3) one possible mechanism for protein misfolds is misincorporation of BMAA into proteins as a substitute for L-serine; and (4) chronic exposure to BMAA through diet or environmental exposures to cyanobacterial blooms can cause neurodegenerative disease. We here identify multiple errors in their critique including the following: (1) their review selectively cites the published literature; (2) the authors reported favorably on HILIC methods of BMAA detection while the literature shows significant matrix effects and peak coelution in HILIC that may prevent detection and quantification of BMAA in cyanobacteria; (3) the authors build alternative arguments to the BMAA hypothesis, rather than explain the published literature which, to date, has been unable to refute the BMAA hypothesis; and (4) the authors erroneously attribute methods to incorrect studies, indicative of a failure to carefully consider all relevant publications. The lack of attention to BMAA research begins with the review’s title which incorrectly refers to BMAA as a “non-essential” amino acid. Research regarding chronic exposure to BMAA as a cause of human neurodegenerative diseases is emerging and requires additional resources, validation, and research. Here, we propose strategies for improvement in the execution and reporting of analytical methods and the need for additional and well-executed inter-lab comparisons for BMAA quantitation. We emphasize the need for optimization and validation of analytical methods to ensure that they are fit-for-purpose. Although there remain gaps in the literature, an increasingly large body of data from multiple independent labs using orthogonal methods provides increasing evidence that chronic exposure to BMAA may be a risk factor for neurological illness.
Recent confirmation that the toxic unsaturated aldehyde crotonaldehyde (CA) contributes to protein damage during lipid peroxidation confers interest on the molecular actions of this substance. ...However, since a plethora of structurally related aldehydes form during membrane oxidation, clarifying the toxicological significance of individual products (e.g., CA) is challenging. To facilitate study of the mechanisms underlying CA toxicity, we explored the possibility that it can be formed enzymatically from an unsaturated precursor, crotyl alcohol. This is analogous to the way allyl alcohol is converted in vivo to its toxic oxidation product, acrolein. In kinetic studies, we found that crotyl alcohol was readily oxidized by equine liver alcohol dehydrogenase, with electrospray-mass spectrometry confirming that CA was the main product formed. Moreover, in mouse hepatocytes, crotyl alcohol produced marked time- and concentration-dependent cell killing as well as pronounced glutathione depletion. Both cytotoxicity and glutathione loss were abolished by the alcohol dehydrogenase inhibitor 4-methylpyrazole, indicating an oxidation product mediated these effects. In keeping with expectations that carbonyl-retaining Michael addition adducts would feature prominently during protein modification by CA, exposure to crotyl alcohol resulted in marked carbonylation of a wide range of cell proteins, an effect that was also abolished by 4-methylpyrazole. Damage to a subset of small proteins (e.g., 29, 32, 33 kDa) closely correlated with the severity of cell death. Collectively, these results demonstrate that crotyl alcohol is a useful tool for studying the biochemical and molecular events accompanying intracellular CA formation.
Plasma cortisol concentrations in farmed rainbow trout (Oncorhynchus mykiss) were used to determine the stress caused by feeding, counting, grading and harvesting. The effect of carrying out these ...practices with the addition of an aerator was also determined. The cortisol concentration in trout plasma was assessed using enzyme immunoassay (EIA). Pre-feeding levels were found to be 3-4 ng/ml. Feeding, counting, grading and harvesting produced significant elevations in plasma cortisol. The presence of an aerator during these practices significantly reduced this cortisol response. The plasma cortisol response during winter grading was significantly less (p<0.0001) compared to summer grading. Grading was also found to be a more stressful practice than feeding or counting. The cortisol response to grading was dependent on fish size (p = 0.0027). Winter harvesting was more stressful than summer harvesting (p = 0.0134), suggesting that lower temperatures may prolong the loss of consciousness. This study suggests that stress incurred by the trout during fish farming practices can be significantly reduced by oxygenating the water.
Using specific descriptive phrases about experiences, it is possible to classify a group of people into categories. The fewer the number of these experiences used in the classification, the less ...likely an individual's ¿personality¿ will be preserved. The greater the number of items involved, the greater the information processing-problem. This is the situation of the manpower administrator who in order to maintain individualities is forced to cope with quantities of information. One solution for the administrator is to transform his personnel information into a form compatible with the use of high-speed data processing equipment and take advantage of equipment's ability to perform complex operations with speed and skill. This requires that the information be descriptive enough to be meaningful and that it be organized so that it can be coded. This paper develops a technique for handling one segment of personnel information ¿ experience. The technique is to describe a person through information related to his work experience. The study covers the development of such an experience matrix and shows that such information can be reasonably classified in this form. Two factor analyses were carried out. The direct factor analysis developed factors of combinations of work experience which have a reasonable degree of independence. The inverse factor analysis because of the complex method of interpretation was less satisfactory.
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