Incubation temperature in the Australasian Gannet Moms senator

Gannets (Sulidae) and some other pelecaniforms incubate their eggs under the webs of their totipalmate feet. These species have a wide latitudinal distribution from tropics to subarctic, but little is known of the incubation temperatures attained. I measured egg temperatures of the Australasian Gannet Morns serrator at Cape Kidnappers, New Zealand, employing a data logger to obtain records every 15 min for day-long sample periods at undisturbed nests. Egg surface temperatures were relatively stable and little affected by ambient temperature. Mean surface temperature of natural eggs was 34.9^oC for samples taken during the first 4 days of incubation, but this then increased and stabilized at 36.5^oC. Internal temperature of pipped eggs was about 1^oC higher, attributable to embryonic heat production. Upper surface temperature of eggs kept in a fixed position was about 2^oC below deep adult body temperature (40.3^oC), suggesting heat is transferred directly from the body through the feet. Clutch size does not appear to be limited by an inability to warm two eggs. These results are in general agreement with measurements from other web incubators and are well within the range for species with conventional brood patch incubation.     

Toe pad morphology and mechanisms of sticking in frogs

Sticking ability in frogs was measured on a series of different substrates. Analysis of performance suggests that frogs use two sticking mechanisms: interlocking on rough surfaces and capillarity on smooth surfaces. There is a correlation between morphological specializations of the toe pad and sticking ability, but these morphological features are not unique to arboreal species. Terrestrial species that use leaves as resting sites during times of inactivity have many of the same morphological specializations and stick as well as the strictly arboreal species.     

Plant coated vesicles

Abstract. Coated vesicles are organelles frequently encountered in many plant cell types often in association with the plasma membrane, Golgi apparatus, partially coated reticulum and multivesicular bodies. They are readily identified by a characteristic cage or basket composed of interlocking triskelions of the protein clathrin which are bound to the surface of the vesicle membrane. Although their transport function has been well studied and characterized in mammalian systems, the possible importance of coated vesicles as transport organelles in plant cells is only just beginning to be explored. In this review, the authors describe the structure of higher plant coated vesicles and discuss their possible involvement in the endocytosis of marcromolecules, in exocytosis and in the intracellular transport of material between cytoplasmic compartments. Their possible role in maintaining the macromolecular composition of the plasma membrane whilst allowing recycling of excess lipid bilayer and their potential application as vehicles for the introduction of foreign macromolecules into plant cells are discussed.     

A Man Out of Place: Herbert Spencer Jennings at Johns Hopkins, 1906-1938

Herbert Spencer Jennings (1868–1947) succeeded W. K. Brooksas Director of the Zoological Laboratory at Johns Hopkins Universityin 1910. His scientific work in the next two decades includedexperimental genetics of protozoa and mathematical analysisof the linear arrangement of chromosomes. At the same time,Jennings was involved in philosophical discussions of the natureof biological thought. His point of view expressed the biologist'sawareness of diversity and historical process, against boththe excesses of vitalism and of the modern reductionist methodsof physico-chemical biology. These philosophical discussionsare seen against the background of his difficulty in buildingup the zoological laboratory at Johns Hopkins in the 1920s,when the university tried unsuccessfully to return to the idealof pure research which had guided it under its first president.Moreover, Jennings faced strong competition for resources fromwithin the university itself, especially at the medical school.His position illustrates the predicament of the modern generalbiologist in an environment increasinglydominated by the medicalsciences     

The Utilization of Glucose and Proline by Culture Forms of Trypanosoma brucei*

Exponentially dividing culture forms of Trypanosoma brucei did not utilize glucose provided in the culture medium. The inclusion of 2-deoxyglucose in the medium had no effect on the growth of the trypanosomes. Glucose could be replaced by proline in the liquid phase of biphasic medium without affecting the doubling time of the organisms. Proline added to the culture medium in this way disappeared during the log phase of growth. Glucose in the culture medium was used by the trypanosomes only when the stationary growth phase had been reached. Lipid accumulated in stationary phase trypanosomes grown in glucose-containing medium, but there was no lipid accumulation in log phase organisms or in those which had been grown in proline-containing medium. Bloodstream trypanosomes transferred to liquid medium rapidly utilized glucose over the first 12 hr of culture, and this was accompanied by an accumulation of free pyruvate in the medium. The rate of glucose utilization fell off over the next 36 hr; this was accompanied by a lowering of free pyruvate in the medium and a rise in the proline oxidase activity of the trypanosomes. The possible biologic significance of proline to trypanosomes developing in the midgut of the tsetse vector is discussed.     

Distinguishing between <Emphasis Type="Italic">X</Emphasis>, <Emphasis Type="Italic">Y</Emphasis> and <Emphasis Type="Italic">YY</Emphasis>-bearing Human Spermatozoa by Fluorescence and DNA Content

Assays for DNA content show that human spermatozoa with X, F or YY chromosome constitutions can be reliably distinguished by their fluorescence with quinacrine.     

Studies on the Ship-fouling Alga Enteromorpha II. The Effect of Certain Enzymes on the Adhesion of Zoospores

A method for assessing the adhesion of settled zoospores ofEnteromorpha intestinalis is described. Using this method, the effect of certain enzymes on the attachmentprocess has been studied and the biochemical nature of the secretedadhesive inferred from the results. Although considerable variation in adhesive ability has beenshown to exist between spores from different parent sourcescertain enzymes produce a consistent weakening action on adhesion.Trypsin, pronase, and a-amylase are especially active in thisrespect. The experimental results demonstrate that the -amylaseeffect, although not quite so great as that of the two proteolyticenzymes is, however, genuine. In conjunction with the previous paper it has been shown thatadhesive production is a rapid process, completed within minutesof initial contact and that at this early stage the adhesivematerial is particularly susceptible to proteolytic attack. The results offer the possibility of a biological method forthe control of algal fouling.     

Action of Sorghum Proteinase on the Protein Bodies of Sorghum Starchy Endosperm

Protein bodies isolated from the starchy endosperm of ungerminatedsorghum exhibited some autolytic activity but seemed incapableof significant self-hydrolysis. Enzyme assay, transmission electronmicroscopy, sodium dodecyl sulphate—polyacrylamide gelelectrophoresis and amino acid analysis revealed that a proteinaseextract from germinated sorghum could degrade the protein bodiesin a manner resembling that which takes place in vivo. The proteinbodies were degraded mainly from the periphery. Glutelin (matrixprotein) was first hydrolysed, followed by the prolamin proteinbody protein. Proteinase extracts from both the germ and endospermof germinated sorghum were capable of degrading the proteinbodies. This finding is consistent with the concept that theproteinase is synthesized in the germ and then secreted intothe starchy endosperm during germination. Key words: Sorghum bicolor, protein body degradation, proteinase.