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911.
Pascal Abel Ingmar Werneburg 《Biological reviews of the Cambridge Philosophical Society》2021,96(5):2229-2257
The morphology of the temporal region in the tetrapod skull traditionally has been a widely discussed feature of vertebrate anatomy. The evolution of different temporal openings in Amniota (mammals, birds, and reptiles), Lissamphibia (frogs, salamanders, and caecilians), and several extinct tetrapod groups has sparked debates on the phylogenetic, developmental, and functional background of this region in the tetrapod skull. This led most famously to the erection of different amniote taxa based on the number and position of temporal fenestrae in their skulls. However, most of these taxa are no longer recognised to represent natural groupings and the morphology of the temporal region is not necessarily an adequate trait for use in the reconstruction of amniote phylogenies. Yet, new fossil finds, most notably of parareptiles and stem-turtles, as well as modern embryological and biomechanical studies continue to provide new insights into the morphological diversity of the temporal region. Here, we introduce a novel comprehensive classification scheme for the various temporal morphotypes in all Tetrapoda that is independent of phylogeny and previous terminology and may facilitate morphological comparisons in future studies. We then review the history of research on the temporal region in the tetrapod skull. We document how, from the early 19th century with the first recognition of differences in the temporal region to the first proposals of phylogenetic relationships and their assessment over the centuries, the phylogenetic perspective on the temporal region has developed, and we highlight the controversies that still remain. We also compare the different functional and developmental drivers proposed for the observed morphological diversity and how the effects of internal and external factors on the structure of the tetrapod skull have been interpreted. 相似文献
912.
Ariadna P. Velázquez Takashi Tatsuta Ruben Ghillebert Ingmar Drescher Martin Graef 《The Journal of cell biology》2016,212(6):621-631
Lipid droplets (LDs) are conserved organelles for intracellular neutral lipid storage. Recent studies suggest that LDs function as direct lipid sources for autophagy, a central catabolic process in homeostasis and stress response. Here, we demonstrate that LDs are dispensable as a membrane source for autophagy, but fulfill critical functions for endoplasmic reticulum (ER) homeostasis linked to autophagy regulation. In the absence of LDs, yeast cells display alterations in their phospholipid composition and fail to buffer de novo fatty acid (FA) synthesis causing chronic stress and morphologic changes in the ER. These defects compromise regulation of autophagy, including formation of multiple aberrant Atg8 puncta and drastically impaired autophagosome biogenesis, leading to severe defects in nutrient stress survival. Importantly, metabolically corrected phospholipid composition and improved FA resistance of LD-deficient cells cure autophagy and cell survival. Together, our findings provide novel insight into the complex interrelation between LD-mediated lipid homeostasis and the regulation of autophagy potentially relevant for neurodegenerative and metabolic diseases. 相似文献
913.
In isoelectric focusing it is theoretically advantageous to use the highest voltages possible. Limitations are due to uneven heat evolution because of uneven conductivity of the individual carrier ampholyte molecules and/or insufficient cooling. The availability of a new carrier ampholyte. Pharmalyte, and a new flatbed apparatus with improved properties has made it possible to perform experiments at very high voltages. The results are discussed in terms of zone sharpness, resolution, and temperature profile. A method is proposed for accurate pI determinations, considering the temperature dependence of pI and the actual temperature in the gel. 相似文献
914.
Naim Michael; Dukan Emmanuel; Yaron Lyat; Levinson Martha; Zehavi Uri 《Chemical senses》1986,11(4):471-483
The maximal perceived sweet intensity (Ipmax) and the sweetpersistence constant (T) of neohesperidin dihydrochalcone (NHD),were significantly reduced in a mixture containing naringin(NAR), a bitter flavone analog of NHD Sucrose octa-acetate (SOA),another bitter stimulus, reduced the Ipmax of NHD in mixtures,but no appreciable decrease in T values was found. Linear regressionanalyses performed on the IPmax data of either NHD + NAR orNHD + SOA (logIpmax versus log concentration) produced slopevalues lower than those of NHD alone. Moreover, taste similarityexperiments revealed that the mixture of NHD + NAR was locatedfurther than NHD from the sugar area in the multi-dimensionalscaling (MDS) map. It is concluded that the reduction in Tvaluesof NHD by NAR was apparently related to the reduced Ipmax levelsand that such a mixture produces a sweet quality inferior tothat of NHD. 相似文献
915.
Eliahu Stoupel Eugeny Abramson Jaqueline Sulkes Joseph Martfel Nechama Stein Meir Handelman Michael Shimshoni Pnina Zadka Uri Gabbay 《International journal of biometeorology》1995,38(4):199-203
In recent years, the possible association of changes in mortality from cardiovascular disease and myocardial infarction (MI) and deaths related to violence and the suicide rate has been repeatedly discussed. This study examined the relationship between cosmic physical changes (solar, geomagnetic and other space activity parameters) and changes in the total number of in-hospital and MI-related deaths and deaths from suicide to determine if a relationship exists between the distribution of total and MI-related deaths with suicide over time; some differences in the serotonergic mechanisms involved in the pathogenesis of MI and suicide were also taken into account. All suicides (n=2359) registered in the State of Israel from 1981 to 1989 (108 months) were analysed and compared with the total number of deaths (n=15601) and deaths from MI (n=1573) in a large university hospital over 180 months (1974–1989). The following were the main features of the Results. (1) Monthly suicide rate was correlated with space proton flux (r=0.42,P=0.0001) and with geomagnetic activity (r=–0.22,P=0.03). (2) Total hospital and MI-related deaths were correlated with solar activity parameters (r=0.35,P<0.001) and radiowave propagation (r=0.52-0.44,P<0.001), an with proton flux (r=–0.3 to –0.26,P<0.01). (3) Monthly suicide distribution over 108 months was correlated with MI (r=–0.33,P=0.0005) and total hospital mortality (r=–0.22,P=0.024). (4) Gender differences were prominent. We conclude that the monthly distributions of suicides and deaths from MI are adversely related to many environmental physical parameters and negatively correlated with each other. 相似文献
916.
Uri Gerson 《BioControl》1968,13(2):163-173
Résumé La biologie des aphelinidesAphytis hispanicus (Mercet) etProspaltella inquirenda
Silvestri, respectivement ecto et endoparasite deParlatoria pergandii
Comstock, a été étudiée comparativement en laboratoire.A. hispanicus accomplit son cycle en 34 jours environ à 20 °C et en 16 jours à 28 °C; il produit en moyenne 23,8 descendants, tandis que
pourP. inquirenda ces durées sont de 62 et 26 jours et le nombre moyen de descendants 20,6. Le comportement pendant l'oviposition et les interactions
diverses entre l'h?te et le parasite ont été notés. Le nectar d'agrumes a prolongé la vie des deux parasites autant que le
miel.A. hispanicus a généralement une vie plus prolongée queP. inquirenda. Le premier parasite a mieux survécu dans des conditions de forte humidité relative (61%, 80%), maisP. inquirenda s'est trouvé favorisé dans des conditions de faible humidité relative, ainsi qu'après une exposition à des températures extrêmes.
En conclusion,A. hispanicus a un taux plus rapide de croissance, tandis queP. inquirenda est mieux adapté aux conditions naturelles.
This research has been finaneed in part by Grant No. FG-Is-227 made by the United States Department of Agriculture under P.L. 480. 相似文献
This research has been finaneed in part by Grant No. FG-Is-227 made by the United States Department of Agriculture under P.L. 480. 相似文献
917.
The isoelectrofocusing patterns of
-amino acid oxidase (LAO) from venom gland homogenates and of the secreted venom of Vipera palaestinae have been compared. The LAO isozyme profile of actively synthesizing gland spans over a wider range of pIs (4.8–6.0) and includes more variants as compared with the profile of the secreted venom. A basic shift of the isoelectrofocusing pattern of LAO obtained by treatment of the gland homogenate or the venom with neuraminidase indicates that sialic acid residues are responsible for the changes in the electronegativity of the isozymes. Analyses of subcellular fractions show that the microsomal fraction of the venom gland homogenate exhibits the highest multiplicity of molecular forms of LAO, whereas the fraction including the secretory granules has an isozyme profile similar to the venom. Double labelling experiments show that the newly synthesized LAO include isozymes which span over a wide range of pIs, whereas later on labelling of the more acidic isozymes is prominent. The results obtained may suggest that the sialic acid residues which are attached to LAO during its transport serve as “markers” for secretion. 相似文献
918.
Maarit Hallikainen Essi Sarkkinen Ingmar Wester Matti Uusitupa 《BMC cardiovascular disorders》2002,2(1):14-7
Background
The short-term cholesterol-lowering efficacy of plant stanol esters has been open to debate, and the data from different clinical studies with hypercholesterolemic subjects are variable, partly due to lack of systematic studies. Therefore, we investigated the time in days needed to obtain the full cholesterol-lowering effect of stanol esters in hypercholesterolemic subjects. 相似文献919.
Gadiel Saper Stanislav Kler Roi Asor Ariella Oppenheim Uri Raviv Daniel Harries 《Nucleic acids research》2013,41(3):1569-1580
Using small-angle X-ray scattering, we determined the three-dimensional packing architecture of the minichromosome confined within the SV40 virus. In solution, the minichromosome, composed of closed circular dsDNA complexed in nucleosomes, was shown to be structurally similar to cellular chromatin. In contrast, we find a unique organization of the nanometrically encapsidated chromatin, whereby minichromosomal density is somewhat higher at the center of the capsid and decreases towards the walls. This organization is in excellent agreement with a coarse-grained computer model, accounting for tethered nucleosomal interactions under viral capsid confinement. With analogy to confined liquid crystals, but contrary to the solenoid structure of cellular chromatin, our simulations indicate that the nucleosomes within the capsid lack orientational order. Nucleosomes in the layer adjacent to the capsid wall, however, align with the boundary, thereby inducing a ‘molten droplet’ state of the chromatin. These findings indicate that nucleosomal interactions suffice to predict the genome organization in polyomavirus capsids and underscore the adaptable nature of the eukaryotic chromatin architecture to nanoscale confinement. 相似文献