Hematological response of Japanese quail to acute hemorrhagic stress

Hematological and serum biochemical changes in response to hemorrhagic stress were determined in both sexes of juvenile and adult Coturnix coturnix japonica over 3 day period following a mechanical hemorrhage of 30% of the calculated total blood volume. There was an initial shift posthemorrhage towards greater numbers of more mature erythrocytes and fewer circulating reticulocytes. Reticulocytosis was indicated 48-72 hr posthemorrhage. Glucose and lactic acid dehydrogenase levels increased after hemorrhage. Serum beta-glucuronidase was elevated only in adults. Japanese quail seemed to recover from hemorrhage more rapidly than had been reported for chickens, other birds and mammals.     

Hematological alterations and response to acute hypobaric stress.

Exposure of rats to simulated altitude (15,000 ft) for 1 day and 3 and 9 wk produced progressive polycythemia, elevated 2,3-diphosphoglycerate levels and raised P50 values; the latter two parameters decreased toward control values after 9 wk. Carbon monoxide (38-43% HbCO) exposure produced polycythemia after 3- and 9-wk exposure, no change in 2,3-DPG and a fall in P50 value. Ten days' treatment with sodium cyanate produced a large decrease in 2,3-DPG and P50. Survival during 90 min of acute hypobaria (0.3 atm) under Nembutal anesthesia was highest with NaOCN (75%), intermediate with 3- and 9-wk exposure to altitude and CO (56-58%) lower in 1-day altitude exposure (44%) and lowest in controls (5%). Heart and ventilation rate was monitored during this hypobaric test and response patterns established for each exposure/treatment. In states of extreme oxygen deprivation the results suggest, in order of importance, the survival value of 1) increased oxygen-hemoglobin affinity, and 2) polycythemia.     

Biochemical indicators of water stress in sunflower seedlings

The free proline and chlorophyll contents, and the chlorophyllase, peroxidase and nitrate-reductase activities were determined in sunflower seedlings grown under controlled conditions and submitted to water stress induced by 14 % polyethyleneglycolj (M_r = 4000) or isotonic NaCl solution. Combined free proline content and peroxidase activity may be used for detection of the factor inducing water stress.     

Biochemical indicators of the water stress in maize seedlings

Free proline and chlorophyll contents, chlorophyllase, peroxidase and nitrate reductase activities were determined in maize seedlings grown under controlled conditions and submitted to water stress induced by 14 % PEG-4000 or NaCl (isotonic). All the parameters studied showed a significant response to the water stress, but the level of free proline and peroxidase activity together may preferentially be used for the diagnosis of osmotic stress or saline-osmotic stress.     

Spiral valve parasites of blue and common thresher sharks as indicators of shark feeding behaviour and ecology

This study documented the parasite faunas of the spiral valves of blue sharks Prionace glauca (L. 1758) and common thresher sharks Alopias vulpinus (Bonnaterre, 1788) caught in the California Current Large Marine Ecosystem (CCLME) north of the Mexican border. The spiral valves of 18 blue and 19 thresher sharks caught in the CCLME from 2009 to 2013 were examined for parasites. Seven parasite taxa were found in blue sharks and nine in threshers. The tetraphyllidean cestode Anthobothrium sp. (78% prevalence) was the most common parasite in blue sharks, and the phyllobothriid cestode Paraorygmatobothrium sp. (90% prevalence) was the most common in threshers. An adult nematode of the genus Piscicapillaria was found in threshers for the first time and may be a new species. Adult individuals of Hysterothylacium sp. were found in both shark species. The adult acanthocephalan Rhadinorhynchus cololabis and remains of the parasitic copepod Pennella sp. – both parasites of Pacific saury, Cololabis saira – were found in the intestines of threshers, indicating recent feeding on saury. This study paves the way for a more comprehensive examination, including more samples and a wider variety of shark species, to provide a greater understanding of shark feeding behaviour and possibly provide information on shark population biology.     

鲨鱼

鲨鱼,古代称鲛、鲛鲨、沙鱼。是指软骨鱼纲板鳃鱼亚纲鲨鱼总目鱼类,体呈鱼雷形或纺锤形,鳃裂每侧6-7个,鳍1个或2个,尾鳍发达,歪形,臂鳍有时消失。海生,少数种类进入淡水,为一群游速快的中大型海洋鱼类。鲨鱼与人类关系密切,是重要食品,工业原料,药用材料,科研用品。     

Biochemical indicators of salt stress in Plantago maritima: Implications for environmental stress assessment

Our study is focused on native spontaneous species of saline ecosystems Plantago maritima. Plants were cultivated at several salt concentrations (0, 50, 100, 200, 300, 400 and 500 mM NaCl) in a glass greenhouse under semi-controlled conditions. Growth parameters, water parameters and ionic status were determined and they were used as criteria to assess the response of P. maritima under a salinity gradient. Catalase, guaiacaol and ascobate peroxidase activities, total protein and proline were also determined. Our results show that P. maritima is a facultative halophyte capable of expressing its maximum growth potential at relatively low concentrations of salt (less than 3 g l⁻¹ NaCl). At high doses of salt (concentrations > 200 mM), the decrease in the growth of P. maritima is associated to a decrease in the uptake of K⁺. There is a disruption of the water intake of their organs and therefore results an invasion of the cytoplasm by Na⁺ toxic ion. However, stressed plants use K⁺ more sparingly. They invest especially in the production of biomass expressed by the dry weight of the shoots, and they use Na⁺ and proline for osmotic adjustment. The halophyte studied is able to accumulate high levels of proline in response to increasing salt concentration. The accumulation of the amino compound, mainly in roots, is interpreted as an indicator of salt tolerance. Additionally, a significant correlation between the tolerance of the plants to salinity and the activity of several antioxidant enzymes has been observed. Hence, we suggest the possibility of using these activities as a biochemical indicator for salt tolerance in P. maritima. Our study points out two types of biomarkers of salt exposure: enzymatic biomarkers in the leaves and proline content in the roots. Both did show very good correlation with salt exposure, and thus may be considered good biomarkers of exposure with a very good dose–response relationship.     

Oxidative processes as indicators of chemical stress in marine bivalves

Deleterious effects of environmental contaminants could be due to enhanced prooxidant forces overcoming antioxidant defences. Before practical biomarkers based on free radical biology will be generally accepted and validated in situ, additional research is required concerning normal physiological and environmental influences on the relevant systems. The aims of this study were to evaluate in situ the importance of oxyradical production in the presence and absence of pollutants and to characterize some antioxidant systems in Mytilus edulis L. Specimens of M. edulis L. were transplanted from a reference site (Franquelin) to Baie Comeau (Baie des Anglais), on the North shore of the St. Lawrence maritime estuary, where are found aluminium and pulp and paper plants. An oxidative stress was observed in mussels submitted to a chronic exposure in the polluted environment. Variations of pro-and anti-oxidant molecules involved in oxidative processes were related in part to seasonal and physico-chemical influences. Catalase activity, malondialdehyde and glutathione concentrations will be useful as biomarkers of stress in situ since they react to anthropogenic influence and to abiotic factors such as emersion period and temperature.     

Enamel hypoplasias as indicators of developmental stress in pongids and hominids

This paper reports the results from a study of enamel hypoplasia in the deciduous dentition of free-living Liberian chimpanzees (Pan troglodytes verus). The entire study collection includes 280 specimens (278 skulls plus two unassociated mandibles), of which 70 are young enough to retain some decidous teeth. Among the subsample of infants, the total frequency of hypoplasia summed over all teeth in any individual reaches 80%, being expressed in the form of pits rather than transverse lines. Hypoplasia of a linear form was common in the permanent dentition, attaining a frequency of 46.7% on maxillary central incisors and 69.7% on mandibular canines.     

Fluctuation of oxidative stress indicators in Salix nigra seeds during priming

Salix nigra seeds subjected to increased humidification show a decrease in normal germination (NG) during early imbibition followed by a recovery in that parameter at increasing imbibition times. Since photo-oxidized seeds contain high levels of reactive oxygen species (ROS), it is possible to infer that the atypical decrease in NG is a consequence of a higher ROS mobilization at early imbibition and the subsequent recovery from an increase in antioxidant activity. In this study, several oxidative stress indicators were evaluated in photo-oxidized seeds subjected to priming. ROS production was studied using electronic spin resonance spectroscopy, spontaneous chemiluminescence (SCL), spectrophotometry (with XTT), and histochemical (with DAB and NBT) and cytochemical (with CeCl(3)) techniques. Four indicators of molecular damage were monitored: lipid peroxidation, pigment destruction, protein oxidation, and membrane integrity. Antioxidant activity was evaluated by changes in the enzymes SOD, CAT, APX, and POX. The results revealed that the decrease in NG at the beginning of priming occurs by an oxidative burst, as determined by increases in both SCL and superoxide anion radical (O2(·-)) Such oxidative burst generates lipid peroxidation, protein oxidation, and a decrease in both pigment content and enzyme activities. With increasing hydration, damages are progressively reversed and NG restored, which coincides with the increased activity of antioxidant defences. It is proposed that these novel observations regarding the occurrence of an oxidative burst are related to the high basal ROS levels and the high membrane content retained in the mature embryo tissues.     

The use of histopathological indicators to evaluate contaminant-related stress in fish

As a component of a large research program toevaluate the effects of contaminants on fish healthin the field, histopathological studies have beenconducted to help establish causal relationshipsbetween contaminant exposure and various biologicalresponses. Brown trout (Salmo trutta f. fario)and loach (Barbatula barbatula) were exposedto water diverted from polluted streams undersemi-field conditions at various times during theyear. The histopathological studies revealedseasonal differences in the types and severity oforgan lesions between fish of the two streams. Bothtoxicant-induced alterations and organ lesionsresulting from natural stressors (physicochemicaland limnological water parameters) and secondarystress effects of pollution (diseases) could bedetected. In evaluating the general health ofexperimental and control fish, the use ofhistopathological studies are recommended for makingmore reliable assessments of biochemical responsesin fish exposed to a variety of environmentalstressors. Stereological analysis providesquantitative data on pathological lesions whichhelps to establish correlation with other biomarkersthereby increasing the probability of identifyingcause (stressor) and effect (biomarker) relationships.     

Lipid biomarkers in Symbiodinium dinoflagellates: new indicators of thermal stress

Lipid content and fatty acid profiles of corals and their dinoflagellate endosymbionts are known to vary in response to high-temperature stress. To better understand the heat-stress response in these symbionts, we investigated cultures of Symbiodinium goreauii type C1 and Symbiodinium sp. clade subtype D1 grown under a range of temperatures and durations. The predominant lipids produced by Symbiodinium are palmitic (C16) and stearic (C18) saturated fatty acids and their unsaturated analogs, the polyunsaturated fatty acid docosahexaenoic acid (C22:6, n-3; DHA), and a variety of sterols. Prolonged exposure to high temperature causes the relative amount of unsaturated acids within the C18 fatty acids in Symbiodinium tissue to decrease. Thermal stress also causes a decrease in abundance of fatty acids relative to sterols, as well as the more specific ratio of DHA to an algal 4-methyl sterol. These shifts in fatty acid unsaturation and fatty acid-to-sterol ratios are common to both types C1 and D1, but the apparent thermal threshold of lipid changes is lower for type C1. This work indicates that ratios among free fatty acids and sterols in Symbiodinium can be used as sensitive indicators of thermal stress. If the Symbiodinium lipid stress response is unchanged in hospite, the algal heat-stress biomarkers we have identified could be measured to detect thermal stress within the coral holobiont. These results provide new insights into the potential role of lipids in the overall Symbiodinium thermal stress response.     

Biochemical indicators of thermal stress in Tilapia aurea (Steindachner)

Tilapia aurea muscle and liver adenylate nucleotides, the adenylate energy charge (EC), plasma glucose, cortisol and chloride were monitored during acute and chronic temperature stress. Muscle EC is unaffected during acute cold water exposure but decreases significantly when tilapia are exposed to chronic, sublethal, low temperature stress. The decrease in EC is primarily the result of a decrease in ATP concentration. Plasma glucose and cortisol increase when tilapia are exposed to 11–12° C for 60 min, 11 days, and a 5-week period. Incomplete compensation is evident in 5-week acclimated fish since glucose and cortisol levels are intermediate between controls and acutely stressed fish. Acclimation to 35° C does not significantly affect plasma glucose and cortisol compared to controls (22° C). Plasma chloride is relatively unaffected by acute and chronic temperature stress. Liver adenylates are not significantly affected when tilapia are subjected to a sudden drop in water temperature (22° down to 11° C). EC is a useful indicator of chronic low temperature stress in T. aurea , while plasma glucose and cortisol are sensitive to both acute and chronic temperature stress.     

The behaviour of sharks

Summary Despite the recent upsurge of interest in shark research, the current status of knowledge of the behavioural repertoire of most species is alarmingly incomplete. Clearly, from the steadily decreasing numbers of sharks caught by commercial and sport fishermen, sharks are highly vulnerable to human exploitation. Although education is making inroads, there is still steady opposition to the enforcement of catch limits and management strategies for most species. Accurate life history and behavioural information is required to enforce management policies. Wetherbee et al. (1990) cited a case in which commercial fishermen accused the spiny dogfish of stripping the commerical and recreational fisheries of their herring and salmon catch. A detailed study of the spiny dogfish diet disproved their claims.Sharks are clearly not mindless eating machines, as they have been labelled in the past. They are intelligent and have complex patterns of movement, space utilization, and social organization. Using a combination of remote and direct observational techniques, the scientific community is beginning to have a more complete understanding of these important apex predators in coral reef and oceanic ecosystems. More importantly, researchers who are interested in pursuing the fascinating field of shark behaviour still have a wide choice of direction.