Some analyses of artificially incubated eggs and hatchlings of Green and Loggerhead sea turtles

Eggs of the Green sea turtle ( Chelonia mydas ) and the Loggerhead sea turtle ( Caretta caretta ) were incubated in coral sand or silica sand moistened with distilled water. The eggs and hatchlings were analysed for calcium, magnesium and phosphorus. There was less magnesium but more calcium in the hatchlings than in the original egg contents but this was not influenced by the type of sand used during incubation. The results are interpreted as indicating that the eggshell is the major source of calcium for the developing embryos. The Logger-head sea turtle shows a greater efficiency in the incorporation of yolk magnesium and phosphorus into the embryo than does the Green sea turtle.     

The introduced signal crayfish and native noble crayfish have different effects on sublittoral macroinvertebrate assemblages in boreal lakes

相似文献   

Eradication of Arizona hinshawii from artificially infected turtle eggs

Turtle eggs, 24 h old, were infected with Arizona hinshawii and treated 48 h later with gentamicin sulfate (Garasol; Shering Corp., Allantown, N.J.) by pressure differential egg dip treatment to ascertain the concentration of this reagent required to eradicate this pathogen from eggs. Infected eggs treated with 1,000 or 1,500 micrograms of gentamicin per ml of dip solution eliminated detectable A. hinshawii from eggs as determined by testing shells and embryo-yolk homogenates of 12-day-old eggs and the gastrointestinal tracts, kidneys, livers and gall bladders, and yolks of 50-day-old embryos. Treated eggs produced hatchlings which did not excrete detectable A. hinshawii at 72 h or 30 days after hatching, nor was this organism recovered from the visceral organs of these hatchlings when necropsied 30 days after hatching. Bacteriological assays on infected nontreated eggs showed that greater than 70% of the eggs harbored A. hinshawii, and eggs in this group produced hatchlings which actively excreted and harbored A. hinshawii. Eggs not infected or treated also produced turtles which excreted and systemically carried A. hinshawii and Salmonella spp. though not at the same level as did the turtles produced from infected, nontreated eggs.     

Phylogeography of noble crayfish (Astacus astacus) reveals multiple refugia

相似文献   

Eradication of Arizona hinshawii from artificially infected turtle eggs.

Turtle eggs, 24 h old, were infected with Arizona hinshawii and treated 48 h later with gentamicin sulfate (Garasol; Shering Corp., Allantown, N.J.) by pressure differential egg dip treatment to ascertain the concentration of this reagent required to eradicate this pathogen from eggs. Infected eggs treated with 1,000 or 1,500 micrograms of gentamicin per ml of dip solution eliminated detectable A. hinshawii from eggs as determined by testing shells and embryo-yolk homogenates of 12-day-old eggs and the gastrointestinal tracts, kidneys, livers and gall bladders, and yolks of 50-day-old embryos. Treated eggs produced hatchlings which did not excrete detectable A. hinshawii at 72 h or 30 days after hatching, nor was this organism recovered from the visceral organs of these hatchlings when necropsied 30 days after hatching. Bacteriological assays on infected nontreated eggs showed that greater than 70% of the eggs harbored A. hinshawii, and eggs in this group produced hatchlings which actively excreted and harbored A. hinshawii. Eggs not infected or treated also produced turtles which excreted and systemically carried A. hinshawii and Salmonella spp. though not at the same level as did the turtles produced from infected, nontreated eggs.     

Diurnal variations in physiology and behaviour of the noble crayfish Astacus astacus and the signal crayfish Pacifastacus leniusculus

Heart rate, locomotor activity, and oxygen consumption were recorded simultaneously and continuously in seven individuals of the noble crayfish Astacus astacus (Linneus 1758) and seven individuals of the signal crayfish Pacifastacus leniusculus (Dana 1852). The recordings were made in the laboratory over 7 days at 15°C under a 12?:?12?h dark?:?light regime. Circadian rhythms in heart rate, locomotor activity and oxygen consumption were found both in A. astacus and P. leniusculus. Increased heart rate, locomotor activity, and oxygen consumption levels during night time in both A. astacus and P. leniusculus illustrated expression of nocturnal behaviour. No differences in oxygen consumption levels were observed between A. astacus and P. leniusculus. Also, no significant difference between heart rate levels or heart rate variances was found in A. astacus and P. leniusculus at night. During day, however, heart rate levels, heart rate variances and locomotor activity were higher in P. leniusculus than in A. astacus. The higher activity level in P. leniusculus than in A. astacus during daytime indicates that P. leniusculus is less strictly nocturnal than is A. astacus.     

Diurnal variations in physiology and behaviour of the noble crayfish Astacus astacus and the signal crayfish Pacifastacus leniusculus

Heart rate, locomotor activity, and oxygen consumption were recorded simultaneously and continuously in seven individuals of the noble crayfish Astacus astacus (Linneus 1758) and seven individuals of the signal crayfish Pacifastacus leniusculus (Dana 1852). The recordings were made in the laboratory over 7 days at 15°C under a 12 : 12 h dark : light regime. Circadian rhythms in heart rate, locomotor activity and oxygen consumption were found both in A. astacus and P. leniusculus. Increased heart rate, locomotor activity, and oxygen consumption levels during night time in both A. astacus and P. leniusculus illustrated expression of nocturnal behaviour. No differences in oxygen consumption levels were observed between A. astacus and P. leniusculus. Also, no significant difference between heart rate levels or heart rate variances was found in A. astacus and P. leniusculus at night. During day, however, heart rate levels, heart rate variances and locomotor activity were higher in P. leniusculus than in A. astacus. The higher activity level in P. leniusculus than in A. astacus during daytime indicates that P. leniusculus is less strictly nocturnal than is A. astacus.     

Gas exchange and hatchability of chicken eggs incubated at simulated high altitude

Chicken eggs laid at sea level were incubated at sea level (control conditions), at a simulated altitude of 5.5 km without any further measures (natural conditions), and at a simulated altitude of 5.7 km at optimal incubator gas composition (optimal conditions). Under optimal conditions the incubator relative humidity was 70% throughout incubation, the gas mixture supplied to the incubator contained 45% O2-55% N2, and the ventilation rate was reduced to 6% of control in order to maintain the normal air-space gas tensions and to compensate for the increased eggshell conductance at altitude. The embryos that developed under control conditions showed a normal CO2 production with 94% hatchability of fertile eggs. Under natural conditions at altitude all embryos died within a few days. Optimal conditions resulted in an almost normal gas exchange and in an improvement of hatchability from 0 to 81% of fertile eggs.     

The killing of salmonella bacteria from ducks' eggs by heating

Summary At temperatures between 50 and 60°C. the decrease of the number of individuals ofSalmonella typhi-murium was measured. This decrease obeys the logarithmic law, and from this the decimation time was determined. It is found to depend in a simple way on the temperature. From the data thus found on the killing of these bacteria, it is also possible to predict the fraction of survivors at rising temperature. This prediction tallies with previous observations of the temperature in a duck's egg during boiling and of the boiling time required for sterilization.     

Blastoderm formation in artificially activated eggs of Pimpla turionellae (Hym.).

Unlaid, explanted eggs of Pimpla turionellae can be activated by mechanical deformation. Time-lapse films of cleavage and blastoderm formation in such eggs show that in some of them the normal central flow of ooplasm, which transports the energids, is reduced or absent. Instead, a peripheral syncytial ring moves along the antero-posterior egg axis and distributes nuclei within the periplasm.     

The effect of artificially inoculated antagonistic bacteria on the prevalence of take-all disease of wheat in field experiments

Bacteria from wheat field soils were screened in vitro and in glasshouse experiments for antagonism to the take-all fungus Gaeumannomyces graminis var. tritici. Field experiments to test the ability of the selected bacteria to reduce naturally occurring take-all disease gave variable results. In the most successful series the yield of spring wheat was doubled and the amount of disease reduced to half the unprotected control value. Failure to show disease control seemed to be due either to a naturally low incidence of the disease on the trial sites or to especially dry soil conditions.     

Envelope surface ultrastructure and specific gravity of artificially fertilized Pacific cod Gadus macrocephalus eggs

The envelope surface ultrastructure and specific gravity of artificially fertilized eggs of the Pacific cod Gadus macrocephalus were examined. The unfertilized, demersal and slightly adhesive eggs of G. macrocephalus were almost spherical and had no oil globules. Wrinkled envelope surface with elaborated hexagonal reticulated patterns and type I micropyle were observed under a scanning electron microscope. The adhesiveness of the eggs was lost at the blastodermal‐cap stage after fertilization. The micropylar canal was sealed by secretion of the perivitelline fluid, and the entire surface became rough. Numerous bacilli were deposited at the micropyle and the outer envelope surface at the late germ‐ring stage and at the embryo five‐eighths around the yolk stage. The micropyle was completely deformed at the embryo seven‐eighths around the yolk stage. The specific gravity of the fertilized G. macrocephalus eggs ranged from c. 1·0316 to 1·0454. These values, however, sharply decreased towards the end stages of egg development to produce pelagic larvae. The ultrastructural changes in the micropyle and envelope surface of the G. macrocephalus eggs protected the embryo from microorganism infections and mechanical stress during the long incubation period. The adhesiveness and specific gravity of the eggs influenced their dispersion potential.     

Predation by signal crayfish Pacifastacus leniusculus on fish eggs and its consequences for coregonid recruitment

The character and magnitude of predation by the invasive, ectothermic Pacifastacus leniusculus, a crayfish widely introduced to Europe and Japan from North America, on the eggs of coregonid fishes, vendace Coregonus albula and whitefish Coregonus lavaretus were examined by experimentation, modelling and field data. The present results showed that P. leniusculus has the potential to be very efficient predator of fish eggs under winter conditions, but the predation by P. leniusculus did not significantly decrease production of coregonid larvae during the years with a high P. leniusculus population in the study lake. Hence, the mortality caused by the novel invertebrate predator appeared to compensate for other yet unexplored mortality factors instead of having an additive effect on the present salmonids.     

胭脂虫肠道细菌的初步研究

目的通过对胭脂虫肠道细菌研究,探讨其生理活动。方法从山东农业大学昆虫温室仙人掌上采集胭脂虫,经表面消毒、分离纯化获得4个细菌菌株,对其细菌形态、培养性状、染色反应、生理生化反应等性状进行测定。结果研究结果表明,上述细菌菌株分别属于明串球菌属、链球菌属、微球菌属和孪生球菌。结论 4个属的细菌在不同温度、pH和NaCl不同浓度培养下,均在2530℃,中性偏碱,低NaCl浓度下生长良好。