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11.
The relationship between dental morphology, sex, body length and age of small cetaceans can be used to determine ontogeny, sexual dimorphism and geographical variation. The objective of this study was to determine the relationship between dental morphology, sex, body size and age. A total of 91 specimens of P. blainvillei and 80 specimens of S. fluviatilis accidentally captured in fisheries or stranded in northern Rio de Janeiro (21 masculine37'-22 masculine25'S), from September 1988 to November 1996 were analysed. The teeth root diameter in P. blainvillei was significantly different between the sex; the values for females were larger than males. In neither species aid we observed significant in variations dimension and number of teeth, thickness of dentine and cemental layers and in the maximum width of cement as a function of body size. Age was related to increases in tooth length, root and cingulum diameters, and maximum width of cement in individuals of P. blainvillei, and tooth and crown lengths and maximum width of cement in individuals of S. fluviatilis. The observation of a linear growth between maximum width of cement and age in both species indicates that the equations obtained can be used to estimate relative age in P. blainvillei and S. fluviatilis in northern of Rio de Janeiro. 相似文献
12.
The ability of two strains of Lactobacillus acidophilus, CRL 640 and CRL 800, to survive and retain their biological activities under frozen storage was determined. Freezing and thawing, as well as frozen storage, damaged the cell membrane, rendering the microorganisms sensitive to sodium chloride and bile salts. Both lactic acid production and proteolytic activity were depressed after 21 days at -20 degreesC, whereas beta-galactosidase activity per cell unit was increased. Cell injury was partially overcome after repair in a salt-rich medium. Copyright 1998 Academic Press. 相似文献
13.
Oliveira Willams Silva Jéssica Luiza S. Cruz-Neto Oswaldo Oliveira Marcela Tomaz P. Fernandes de Albuquerque Isabelle Borges Laís Angélica Lopes Ariadna Valentina 《Journal of plant research》2022,135(2):235-245
Journal of Plant Research - In mixed-ploidy populations, newly formed polyploids initially occur at low frequencies when compared to diploids. However, polyploidy may lead to morphological and... 相似文献
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JM Barker CE Cooper PC Withers AP Cruz-Neto 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2012,163(3-4):336-342
We examine here the thermal physiology of the ash-grey mouse, as there is a paucity of data to explain how Australian rodents meet thermoregulatory demands. Most ash-grey mice remained normothermic over a range of ambient temperatures (10°C to 30°C), although they became hyperthermic at high ambient temperatures. One individual entered torpor at ambient temperatures of 20°C and 25°C, with minimal body temperatures of 24.5°C and 28.4°C respectively, before spontaneously arousing. This is the first evidence of torpor use by an Australian murine rodent. Our data suggest that although ash-grey mice have the physiological ability to use torpor, it is used rarely, presumably due to other behavioural and physiological adaptations. Their higher-than-expected basal metabolic rate (1.56±0.25mLO(2)g(-1)h(-1)) indicates that ash-grey mice do not have a frugal approach to energy expenditure. Other standard physiological variables were typical of a generalised rodent. A readily-available omnivorous diet, nocturnal activity, semi-fossorial habit and social behaviour presumably allow a high energy lifestyle. A reluctance to use torpor, despite an apparent physiological ability to do so, supports the idea that the use of torpor reflects a net balance between the costs and benefits of a heterothermic thermoregulatory strategy. 相似文献
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17.
The effects of acute hypoxia and hypercapnia on oxygen consumption of the freshwater European eel 总被引:1,自引:0,他引:1
When exposed to hypoxia, eels Anguilla anguilla were able to regulate and maintain Vo2 down to a water oxygen tension ( Pwo2 ) of about 25 mmHg, a value far below those reported in other studies. When exposed to hypercapnia, eels showed a depression in Vo2 as water carbon dioxide tension ( Pwco2 ) increased. Faced with combined hypoxia-hypercapnia, eels showed an increase in their sensitivity to hypoxia, and the critical oxygen tension increased to 40–45 mmHg. The possible mechanisms underlying these responses were discussed, and the implications of such findings for extensive culture of eels were highlighted. 相似文献
18.
Christine Elizabeth Cooper Ariovaldo P. Cruz-Neto 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2009,179(6):773-781
The honey possum is the only non-volant mammal to feed exclusively on a diet of nectar and pollen. Like other mammalian and
avian nectarivores, previous studies indicated that the honey possum’s basal metabolic rate was higher than predicted for
a marsupial of equivalent body mass. However, these early measurements have been questioned. We re-examined the basal metabolic
rate (2.52 ± 0.222 ml O2 g−1 h−1) of the honey possum and confirm that it is indeed higher (162%) than predicted for other marsupials both before and after
accounting for phylogenetic history. This, together with its small body mass (5.4 ± 0.14 g; 1.3% of that predicted by phylogeny)
may be attributed to its nectarivorous diet and mesic distribution. Its high-basal metabolic rate is associated with a high-standard
body temperature (36.6 ± 0.48°C) and oxygen extraction (19.4%), but interestingly the honey possum has a high point of relative
water economy (17.0°C) and its standard evaporative water loss (4.33 ± 0.394 mg H2O g−1 h−1) is not elevated above that of other marsupials, despite its mesic habitat and high dietary water intake. 相似文献
19.
Bryce, J. H. and ap Rees, T. 1985. Comparison of the respiratorymetabolism of Plantago lanceolata L. and Plantago major L.J.exp. Bot. 36 15591565. The aim of this work was to discover if the respiratory metabolismof the roots of Plantago lanceolata L. differed from that ofthe roots of Plantago major L. Measurements of oxygen uptakeand dry weight of excised root systems during growth of seedlingsprovided evidence that the two species differed in the amountof respiration needed to support a given increase in dry weight.Excised root systems were given a 6-h pulse in [U-14C]sucrosefollowed by a 16.5-h chase in sucrose. The detailed distributionof 14C amongst the major components of the roots at the endof the pulse and the chase revealed no significant differencebetween the two species. Patterns of 14CO2 production from [1-14C],[2-14C], [3,4-14C], and [6-14C]glucose of excised root systemsfrom plants of three ages were similar for the two species.It is suggested that there is no conclusive evidence for anysignificant inherent difference in the respiratory metabolismof the roots of the two species. Key words: 14C sugar metabolism, respiration, roots, Plantago 相似文献
20.
Rapid recycling of triose phosphates in oak stem tissue 总被引:10,自引:3,他引:7
S. A. HILL J. S. WATERHOUSE E. M. FIELD V. R. SWITSUR T. AP REES 《Plant, cell & environment》1995,18(8):931-936
We report the carbon-13 and oxygen-18 isotope ratios in cellulose from the early and late wood of pedunculate oak (Quercus robur L.). The δ13 C value of the early wood correlates best with that of the late wood of the previous year. The δ18O value of the early wood correlates best with that of the late wood of the same year. We suggest that a biochemical explanation of these data is that there is a rapid cycle between hexose monophosphates and triose phosphates in oak stem tissue during cellulose synthesis. Evidence in support of this explanation is provided by the intramolecular distribution of 14C in labelled fructose extracted from cores of wood that had been supplied with [1?14C]- and [6-14C]glucose. 相似文献