scholarly journals No gastric mill in sauropod dinosaurs: new evidence from analysis of gastrolith mass and function in ostriches

2006 ◽  
Vol 274 (1610) ◽  
pp. 635-640 ◽  
Author(s):  
Oliver Wings ◽  
P. Martin Sander
Keyword(s):  
Body Mass ◽  
Digestive System ◽  
Gastric Mill ◽  
Theropod Dinosaurs ◽  
Feeding Experiments ◽  
Stem Lineage ◽  
Order Of Magnitude ◽  
Food Retention ◽  
And Function ◽  
New Evidence

Polished pebbles occasionally found within skeletons of giant herbivorous sauropod dinosaurs are very likely to be gastroliths (stomach stones). Here, we show that based on feeding experiments with ostriches and comparative data for relative gastrolith mass in birds, sauropod gastroliths do not represent the remains of an avian-style gastric mill. Feeding experiments with farm ostriches showed that bird gastroliths experience fast abrasion in the gizzard and do not develop a polish. Relative gastrolith mass in sauropods (gastrolith mass much less than 0.1% of body mass) is at least an order of magnitude less than that in ostriches and other herbivorous birds (gastrolith mass approximates 1% of body mass), also arguing against the presence of a gastric mill in sauropods. Sauropod dinosaurs possibly compensated for their limited oral processing and gastric trituration capabilities by greatly increasing food retention time in the digestive system. Gastrolith clusters of some derived theropod dinosaurs (oviraptorosaurs and ornithomimosaurs) compare well with those of birds, suggesting that the gastric mill evolved in the avian stem lineage.

scholarly journals Phosphorylation-dependent interaction of the synaptic vesicle proteins cysteine string protein and synaptotagmin I

2002 ◽  
Vol 364 (2) ◽  
pp. 343-347 ◽  
Author(s):  
Gareth J.O. EVANS ◽  
Alan MORGAN
Keyword(s):  
Rat Brain ◽  
Direct Interaction ◽  
Secretory Vesicle ◽  
Brain Membrane ◽  
Synaptotagmin I ◽  
Phosphorylated Form ◽  
Order Of Magnitude ◽  
And Function

The secretory vesicle cysteine string proteins (CSPs) are members of the DnaJ family of chaperones, and function at late stages of Ca2+-regulated exocytosis by an unknown mechanism. To determine novel binding partners of CSPs, we employed a pull-down strategy from purified rat brain membrane or cytosolic proteins using recombinant hexahistidine-tagged (His6-)CSP. Western blotting of the CSP-binding proteins identified synaptotagmin I to be a putative binding partner. Furthermore, pull-down assays using cAMP-dependent protein kinase (PKA)-phosphorylated CSP recovered significantly less synaptotagmin. Complexes containing CSP and synaptotagmin were immunoprecipitated from rat brain membranes, further suggesting that these proteins interact in vivo. Binding assays in vitro using recombinant proteins confirmed a direct interaction between the two proteins and demonstrated that the PKA-phosphorylated form of CSP binds synaptotagmin with approximately an order of magnitude lower affinity than the non-phosphorylated form. Genetic studies have implicated each of these proteins in the Ca2+-dependency of exocytosis and, since CSP does not bind Ca2+, this novel interaction might explain the Ca2+-dependent actions of CSP.

A New View of Convective-Diffusive Transport Processes in the Arterial Intima

1991 ◽  
Vol 113 (3) ◽  
pp. 314-329 ◽  
Author(s):  
F. Yuan ◽  
S. Chien ◽  
S. Weinbaum
Keyword(s):  
Early Time ◽  
Transport Processes ◽  
Special Role ◽  
Diffusive Transport ◽  
Internal Elastic Lamina ◽  
Time Model ◽  
Feeding Experiments ◽  
Endothelial Surface ◽  
Extracellular Lipid ◽  
Order Of Magnitude

In this paper a new theoretical framework is presented for analyzing the filtration and macromolecular convective-diffusive transport processes in the intimal region of an artery wall with widely dispersed macromolecular cellular leakage sites, as proposed in the leaky junction-cell turnover hypothesis of Weinbaum et al. [11]. In contrast to existing convection-diffusive models, which assume that the transport is either 1-D, or convection is primarily in a direction normal to the endothelial surface, the present model considers for the first time the nonuniform subendothelial pressure field that arises from the different hydraulic resistances of normal and leaky endothelial clefts and the special role of the internal elastic lamina (IEL) in modulating the horizontal transport of macromolecules after they have passed through the leaky clefts of cells that are either in mitosis or demonstrate IgG labeling. The new theory is able to quantitatively explain the growing body of recent experiments in which an unexpectedly rapid early-time growth of the leakage spot has been observed and the longer time asymptotic behavior in which the leakage spot appears to approach an equilibrium diameter. The new theory also predicts the observed doubling in macromolecular permeability between EBA labeled blue and white areas when the frequency of leakage sites is doubled. This frequency for doubling of permeability, however, is an order of magnitude smaller than predicted by the author’s previous model, Tzeghai et al. [10], in which only convection normal to the endothelial surface was considered and the pressure was uniform in the intima. The longer time model predictions are used to explain the time scale for the formation of liposomes [4] in subendothelial tissue matrix in animal feeding experiments where it has been observed that the extracellular lipid concentration rises sharply prior to the entry of monocytes into the intima [45].

scholarly journals Weaning of Burbot, Lota lota (L.) from Live to Dry Feed Using NaCl as Dietary Attractant

2017 ◽  
Vol 9 (3) ◽  
pp. 7
Author(s):  
Franz Lahnsteiner ◽  
Manfred Kletzl
Keyword(s):  
Body Mass ◽  
Sedimentation Rate ◽  
Condition Factor ◽  
Mortality Rates ◽  
Hepatosomatic Index ◽  
Lota Lota ◽  
Live Feed ◽  
Feeding Experiments ◽  
Feeding Attractant ◽  
Weaning Protocols

Weaning of 150 days post hatch Lota lota from live feed (zooplankton) to formulated dry feed (FDF) was investigated. L. lota could not be forced from live feed to FDF. They refused FDF for periods up to 21 d. Body mass decreased for 20%, condition factor for 15%, and hepatosomatic index for 50%. In 21 days lasting co-feeding experiments with FDF and live feed L. lota selected exclusively the live feed organisms. NaCl in a concentration of 5% was a dietary feeding attractant for L. lota. When FDF was supplemented with 5% NaCl, L. lota could be abruptly weaned from live to dry feed. During a 21 d lasting experiment body mass increased for circa 40%, total length for 10%, condition factor for 5% and hepatosomatic index remained constant. These values were similar to live zooplankton feeding. However, increased mortality of > 20% was recorded for fish fed with the 5% NaCl containing FDF. To reduce mortality FDF was supplemented with zooplankton meal to upgrade its quality and extruded to optimize its density and sedimentation rate. With the adjusted FDF mortality rates were reduced to < 5%. Using the optimized dry feed easy and sustainable weaning protocols were developed where NaCl and zooplankton meal were gradually reduced to adapt fish to pure FDF.

The Early Minoan Occupation of Knossos: A Note on some new Evidence.

1972 ◽  
Vol 22 ◽  
pp. 115-128 ◽  
Author(s):  
John Evans
Keyword(s):  
Bronze Age ◽  
Early Years ◽  
Major Obstacle ◽  
Early Bronze Age ◽  
Form And Function ◽  
Long Period ◽  
Early Stages ◽  
And Function ◽  
The Hill ◽  
New Evidence

Following their discovery of the “Burnt Palace” at Beycesultan in the mid 1950's, Seton Lloyd and James Mellaart drew attention to a number of features of its architecture which seemed to indicate links with the palace architecture of Minoan Crete, and discussed the possible significance of these similarities (Lloyd and Mellaart, 1956 118–123, 1965 61, 62). Whatever this may be in terms of relationships between the two areas in the second millennium B.C., however, it seems clear that they cannot throw any light on the first appearance of palaces in Crete. The problems of the origin and development of the Cretan Bronze Age palaces are complex, and though they have been much discussed since the first excavations in the early years of the century, a major obstacle to progress has always been the lack of precise evidence, or even of any evidence at all, for the early stages of the process. As they stand, most of the palaces are the product of a series of rebuildings and remodellings over a long period, and it is not always clear just what they were like when first erected. Most frustrating of all, however, is the lack of evidence bearing on the question of whether they were preceded, during the Early Bronze Age, by buildings which were in any respect analogous in form and function. It has long been clear that the sites of some of the major Middle and Late Minoan palaces were occupied during the Early Minoan period, but at Phaistos and Knossos at any rate extensive clearing and levelling in preparation for the erection of the Middle Minoan palaces has obliterated practically all traces of the Early Minoan buildings. At Phaistos Branigan has hinted that the fragments of walls found by Pernier (1935, pl. VI) on the highest point of the hill might have belonged to a building of some consequence, possibly similar to the Early Minoan II mansion known as the House on the Hill at Vasiliki (Branigan 1970, p. 41). Branigan thinks that in addition to the rooms mentioned by Pernier, there may be traces of a corridor similar to that in the Vasiliki building. Only the bottom two courses of the walls survive, so that it is difficult to say much about their construction, though it seems to be poorer than that of the walls of some Early Minoan private houses later found by Levi on another part of the site.

Effect of acute nutritional deprivation on diaphragm structure and function in adolescent rats

1992 ◽  
Vol 73 (3) ◽  
pp. 974-978 ◽  
Author(s):  
M. I. Lewis ◽  
G. C. Sieck
Keyword(s):  
Body Mass ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Structure And Function ◽  
Muscle Fiber Type ◽  
Medial Gastrocnemius ◽  
Diaphragm Muscle ◽  
Nutritional Deprivation ◽  
Ad Libitum ◽  
And Function

The influence of 90 h of acute nutritional deprivation (ND; water ad libitum only) on in vitro contractile and fatigue properties, muscle fiber type proportions, and cross-sectional areas (CSA) of the adolescent rat diaphragm was determined. Diaphragm muscle properties in the ND rats were compared with those in control rats (CTL; food and water ad libitum). Acute ND resulted in a 32% reduction in body mass, whereas the body mass of CTL rats increased by 29%. Acute ND resulted in a significant reduction in the mass of the diaphragm (costal, 36%; crural, 43%), soleus (36%), and medial gastrocnemius (45%) muscles. Isometric twitch characteristics of the diaphragm muscle (contraction and half-relaxation times) were prolonged in the ND animals. Peak twitch and maximum tetanic forces were unaffected by ND. Fatigue resistance of the diaphragm muscle was improved in ND animals. Diaphragm muscle fiber type proportions were similar in ND and CTL groups. The CSA of type I and II diaphragm muscle fibers were reduced by 22 and 40%, respectively, in ND animals compared with CTL. We conclude that, whereas an identical protocol of acute ND had no significant effects on diaphragm muscle structure and function in adult rats, adolescent animals exhibit significantly less nutritional reserve. These differences may be due to curtailment of the rapid anabolic rate in growing animals.

The Ecology and Digestive System of the Struthiolariidae (Gastropoda)

1951 ◽  
Vol s3-92 (17) ◽  
pp. 1-25
Author(s):  
J. E. MORTON
Keyword(s):  
Digestive System ◽  
Structure And Function ◽  
Crystalline Style ◽  
Intracellular Digestion ◽  
Mud Flat ◽  
Food Particles ◽  
Gill Filaments ◽  
And Function ◽  
Deposit Feeding ◽  
Muscular Action

The two neozelanic species Struthiolaria papulosa and Pelicaria vermis have been studied as regards ecology, feeding mechanism, and structure and function of the digestive system. They are dwellers on sand or sand-mud-flat, wit h a feeding position just below the surface, where they construct paired siphonal tubes with the rostrum. A ciliary mode of feeding has been acquired by the modification of the gill filaments and the pallial rejection system. The alimentary canal isadapted for deposit feeding and has developed a crystalline style. Food particles are conducted to the stomach by a functionally reduced mucus-secreting oesophagus, where they are subjected to the action of the rotating style, and a complex system of ciliary currents. Digestible par-ticles are passed into paired diverticula, where absorption and intracellular digestion, takes place, while faecal material is surrounded with mucus and formed into firm pellets by the ciliary and muscular action of the intestine. The relationships of the Struthiolariidae are discussed, and their origin from the Aporrhaidae is postulated.

X.—On the Feeding Mechanism of a Mysid Crustacean, Hemimysis Lamornæ

1927 ◽  
Vol 55 (1) ◽  
pp. 219-253 ◽  
Author(s):  
H. Graham Cannon ◽  
S. M. Manton
Keyword(s):  
Digestive System ◽  
Feeding Habits ◽  
Great Length ◽  
Gastric Mill ◽  
General Biology ◽  
Feeding Mechanism ◽  
In Captivity ◽  
Fish Tanks

The general biology of the Mysids has recently been studied at great length by Blegvad (1922) at Copenhagen. His paper, containing a very complete literature list, deals with Mysis inermis, Rathke, Mysis flexuosa, Müller, and Mysis neglecta, Sars. His comments on feeding are limited, and refer chiefly to the nature of the food that the animals ate in captivity. Gelderd's work (1909) on the digestive system of the Schizopoda describes the course taken by the food through the gastric mill, the masticatory functions of this apparatus, and the method by which the masticated food and digestive juices are brought together, but does not deal with the manner in which the food reaches the stomach. An account, then, of the method by which a mysid collects its food would fill a gap in our knowledge of these forms. The only description, as far as we are aware, of the feeding habits of a mysid is that of Depdolla (1923), who worked on Praunus [Mysis] flexuosus, but his account is superficial and in our opinion very inaccurate. The following paper deals with the feeding habits of a small mysid, Hemimysis lamornœ, about 8 mm. long, which has established itself in the larger fish-tanks at the M.B.A. laboratory at Plymouth. It breeds freely all the year round, and can be obtained from the tanks in abundance, although it is stated to be only a rare visitor in the Plymouth district.

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