The development of hepatogenic potency in the endoderm of quail embryos

Development ◽  
1979 ◽  
Vol 52 (1) ◽  
pp. 49-62
Author(s):  
Sumiko Fukuda
Keyword(s):  
Digestive Tract ◽  
The Other ◽  
Chick Embryos ◽  
Posterior Half ◽  
Coelomic Cavity ◽  
Somite Stage ◽  
Anterior Half ◽  
Other Hand ◽  
Cardiac Region ◽  
Cardiac Mesenchyme

Hepatogenic potency of the endoderm is detectable in the anterior half of the endoderm of quail embryos older than 2-somite stage when endodermal fragments are cultured with or without heterologous chick mesenchymes, in the coelomic cavity of 3-day chick embryos. On the other hand, the posterior half of the endoderm never has hepatogenic potency. The hepatogenic potency of the endoderm is gradually stabilised with increasing age. However, expression of hepatogenesis can be affected when the endoderm is associated with inductively active digestive tract mesenchymes. Mesenchyme taken from the presumptive cardiac region (‘cardiac’ mesenchyme) of chick embryos is necessary for the uncommitted anterior endoderm to acquire hepatogenic potency, and this effect is specific for the ‘cardiac’ mesenchyme. The ‘cardiac’ mesenchyme, however, fails to induce hepatic epithelium in the allantoic endoderm, which can differentiate heterotypically when cultured in combination with digestive tract mesenchymes. The evidence presented in this study suggests that the effect of ‘cardiac’ mesenchyme on the acquisition of hepatogenic potency in the endoderm is limited.

Neuroectodermal origin of avian hypothalamo-hypophyseal complex: the role of the ventral neural ridge

Development ◽  
1975 ◽  
Vol 34 (2) ◽  
pp. 311-325
Author(s):  
T. Takor Takor ◽  
A. G. E. Pearse
Keyword(s):  
The Other ◽  
Avian Embryo ◽  
Chick Embryos ◽  
White Leghorn ◽  
Optic Chiasma ◽  
Somite Stage ◽  
White Leghorn Chick ◽  
Caudal Portion ◽  
Neuroectodermal Origin

Embryonic discs from White Leghorn chick embryos (presomite to 12-somite stages) were examined in serial transverse and longitudinal sections. Later stages, up to 21 days, were also examined. The following observations were made: (1) Lateral folding rather than head folding is the mechanism by which the avian embryo is delimited. The process takes place at two terminal points, one cephalic the other caudal. (2) Thickening of the ventral ectoderm around the tip of the presumptive anterior neuropore, beginning at the 4-somite stage, subsequently extends the dorsal neural ridge to form a ventral neural ridge. (3) The cephalic portion of the ventral neural ridge, extending from anterior neuropore to optic chiasma, is mainly incorporated into the alar plates of the diencephalon. (4) The caudal portion, extending from optic chiasma to the stomodeum, gives rise to Rathke's pouch and thus to the adenohypophysis. We conclude that the latter is to be regarded as of neuroectodermal rather than ectodermal (stomodeal) origin, and that some or all of the neuroendocrine nuclei of the hypothalamus are similarly derived from the neuroectoderm of the neural ridge. The hypothalamo-hypophyseal complex is thus to be regarded as a single rather than a composite entity.

scholarly journals Immunocytochemical studies of cardiac myofibrillogenesis in early chick embryos. II. Generation of alpha-actinin dots within titin spots at the time of the first myofibril formation.

1987 ◽  
Vol 105 (6) ◽  
pp. 2795-2801 ◽  
Author(s):  
K T Tokuyasu ◽  
P A Maher
Keyword(s):  
The Other ◽  
Chick Embryos ◽  
Initial Length ◽  
Electron Microscopic ◽  
Somite Stage ◽  
Dense Bodies ◽  
Whole Mount ◽  
Ultrathin Sections ◽  
Per Se ◽  
Immunocytochemical Studies

In whole mount preparations of the 9 somite stage chick embryonic hearts that were immunofluorescently double labeled for titin and alpha-actinin, presumptive myofibrils were recognized as rows of several periodically aligned titin spots. Within these titin spots, smaller alpha-actinin dots were observed. These periodical arrangements of titin spots and alpha-actinin dots were not found in the 7 somite stage hearts. In wide myofibrils in the 10 somite stage hearts, the alpha-actinin dots and titin spots simultaneously became 'lines.' To study the ultrastructural features of the titin-positive regions in the 6-9 somite stage hearts, the thoracic portions of the embryos were immunofluorescently labeled for titin and embedded in resin. Ultrathin sections were mounted on electron microscopic grids and examined in immunofluorescence optics. The titin-positive regions thus identified were then examined in the electron microscope. No readily discernable specific ultrastructural features were found in titin-positive regions of the 6 somite stage cardiac primodia. Examination of the sections of the 9 somite stage hearts, on the other hand, revealed the occasional presence of small dense bodies, Z bodies, in the titin-positive regions. These observations strongly suggest that these Z bodies are the ultrastructural counterparts of the alpha-actinin dots seen by immunofluorescence optics and that they are formed nearly at the time of the formation of the first myofibrils. In some of the nascent myofibrils the Z bodies were found to be considerably narrower than the myofibrils, implying that the Z bodies are required not for the assembly of myofibrils per se but for their stabilization. Immunofluorescent labeling for titin and alpha-actinin revealed that the length of the shortest sarcomeres in the first myofibrils is approximately 1.5 micron, approximately the width of the A bands of mature myofibrils. The possibility that the A bands might define the initial length of nascent sarcomeres was indicated.

scholarly journals β-glucuronidase and β-glucosidase activity of Lactobacillus and Enterococcus Isolated from Human Feces

2010 ◽  
Vol 59 (4) ◽  
pp. 265-269 ◽  
Author(s):  
MARTA MROCZYŃSKA ◽  
ZDZISŁAWA LIBUDZISZ
Keyword(s):  
Digestive Tract ◽  
Large Intestine ◽  
Age Groups ◽  
The Other ◽  
Healthy Children ◽  
Human Feces ◽  
Glucosidase Activity ◽  
Glucuronidase Activity ◽  
Other Hand ◽  
Beta Glucosidase

The domination of microorganisms characterized by excessive activity of the so-called fecal enzymes may be one of the reasons of the large intestine cancers. These enzymes are mainly those that belong to the hydrolase and reductase classes and their excessive activity may lead to disorders in the functioning of the digestive tract. The aim of tise research was to determine the activity of beta-glucuronidase and beta-glucosidase of Lactobacillus and Enterococcus strains isolated from the feces of healthy children, aged 1 and 8, and adults, aged 30 and 80. The analysis included 10 strains isolated from the feces of individuals in each of the age groups. beta-glucuronidase activity in the case of the isolates from children, depending on the strain, equaled from about 0.15 mM/h/mg of protein to 0.26 mM/h/mg of protein and was lower, respectively, by 52.35% and 57.81%, than the beta-glucosidase activity. Simultaneously, the activity of the Lactobacillus enzymes from children was 2.4 times higher, and in case of the isolates obtained from adults they were 4.6 and 2.7 times higher than the activity of the Entercoccus enzymes. The highest beta-glucuronidase activity was observed in Lactobacillus isolates coming from an 80-year-old subject. The differences between the activity of Enterococcus beta-glucuronidase isolated from the feces of 1 and 8 year old children were statistically insignificant. On the other hand, in the case of the subjects aged 30 and 8 the isolates were characterized by activity lower by, respectively. 48% and 37% than the isolates coming from children. The highest beta-glucosidase activity was discovered in the case of Lactobacillus and Enterococcus coming from children, which was higher by 32% than the activity of the isolates from adult persons. Therefore, it was determined that the activity of beta-glucuronidase of Lactobacillus strains isolated from feces from people aged 80 was the highest, and the isolates of the examined microorganisms coming from children were characterized by the highest beta-glucosidase activity.

scholarly journals The effect of three frequently applied antibiotics on the colonization resistance of the digestive tract of mice

1979 ◽  
Vol 82 (3) ◽  
pp. 397-405 ◽  
Author(s):  
H. A. Thijm ◽  
D. van der Waaij
Keyword(s):  
Escherichia Coli ◽  
Digestive Tract ◽  
Treatment Period ◽  
Oral Treatment ◽  
The Other ◽  
Colonization Resistance ◽  
Streptococcus Faecalis ◽  
Other Hand ◽  
Resistant Strains ◽  
Oral Doses

SUMMARYThe influence of treatment with increasing oral doses of three absorbable antibiotics on the colonization resistance of the digestive tract was investigated in mice. Mice treated with ampicillin or epicillin in any of the applied doses had a strongly decreased colonization resistance as demonstrated by ‘bacterial over-growth’ after contamination with resistant strains ofEscherichia coli. After a treatment period of 2 weeks,Streptococcus faecalisbecame resistant in a number of animals. Oral treatment with cephradine on the other hand had no obvious influence on the endogenous flora of the mice, nor was the colonization resistance decreased.

scholarly journals Pengaruh Jenis Kelamin dan Umur Terhadap Karkas dan Sisa Karkas Kerbau Lumpur di Rumah Potong Hewan Banda Aceh

2000 ◽  
Vol 1 (1) ◽  
pp. 22-25
Author(s):  
Mawardi Mohd. Ali
Keyword(s):  
Digestive Tract ◽  
Direct Observation ◽  
Interaction Effect ◽  
The Other ◽  
Other Hand ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Banda Aceh ◽  
Main Factor

ABSTRACT. The effect of sex and old to carcass and offal of swamp Bufallo at Rumah Potong Hewan Banda Aceh, have been done in Banda Aceh as long as 10 days. The material that was used were swamp bufalloes from Banda Aceh regency, as much as 36 bufalloes, that was sparated 18 females and 19 males. The aim of this study was to know the partial and interaction effect of sex and old to carcass percentage and offal of swamp bufalloes. The method used of this study was direct observation at Rumah Potong Hewan. The variable that was knowed were; the heavy of: weight, carcass, head, hide, heart, feet, liver, lungs, spleen, full digestive tract, and the carcass percentage. The data collected was Analyzed by completely Randomized Design (CRD), wich 3x2 factorial pattern and six times replication. As a main factor was old, that was sparated by 3 – 4 years, 4 – 5 years, and 5 years. The data was tested by Duncan’s test. The result of this study showed that was not any interaction effect of old and sex to carcass percentage and offal. Also, that not any effect of sex to carcass percentage, but effect of sex was significance different to offal. The other hand, not any effect of old to carcass percentage and offal.

scholarly journals The influence of season on yield increase and lactation yield in the Ayrshire herd of Viik experimental farm

1967 ◽  
Vol 39 (3) ◽  
pp. 183-190
Author(s):  
Aarne Mäkelä
Keyword(s):  
Digestive Tract ◽  
Age Groups ◽  
Live Weight ◽  
The Other ◽  
Nutritional Requirements ◽  
Feeding Period ◽  
Yield Increase ◽  
Other Hand ◽  
The University

In the present paper the influence of season on the peak production, the duration of the ascending phase, the persistency of lactation, the 12 month production, and the live weight of the cows in the Ayrshire herd of the University of Helsinki experimental farm Viik are investigated. The material consists of cows calving during the period 1950—1965. During this time the indoor feeding was very intensive, satisfying all the nutritional requirements of the cows. At the same time the pastures were intensively cultivated. The size of the herd varied between 60 and 70 cows. The cows were divided into three groups: 1) spring calving cows, 2) cows calving during the pasre season, and 3) autumn calving cows. During the pasture season the peak production of cows in first lactation is c. 2 kg and of cows in later lactations c. 3.5 kg lower than during the indoor feeding period. The peak production of spring and autumn calving cows is on an average approximately the same. The duration of the ascending phase of cows calving during the pasture season is 6—10 days shorter than during the indoor feeding period. The length of the ascending phase is approximately the same for spring and autumn calving cows. The influence of season on the yield increase tangent, which is a measure of the rapidity of yield increase, is negligible. Cows calving during the pasture season and in the autumn are considerably more persistent in their lactations (P2:1-values higher) than cows freshening in the spring. The persistency values of cows calving during the pasture season and in the autumn are on an average approximately equally high. The 12 month lactation yields of autumn calving cows in the different age groups are 400—600 kg, i.e.c. 10 % higher than the corresponding values for cows freshening in spring and during the pasture season. The lactation yields of cows calving in spring and during the pasture season are on an average approximately equally high. The superiority in lactation yield of cows calving in the autumn compared to cows calving in the spring is due to the better persistency of lactation of the autumn calving cows. On the other hand the superiority in lactation yield of autumn calving cows compared to cows calving during the pasture season is due to the higher peak production of the autumn calving cows. The lactation yields of cows calving in spring or during the pasture season are approximately equally high. During the pasture season the average live weight of the cows is 20—30 kg less than during the indoor feeding period, which is due to the smaller contents of the digestive tract of the cow during the pasture season.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

Can the Academic Self-Concept be Positive and Realistic?

2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann
Keyword(s):  
Academic Performance ◽  
Opposite Effect ◽  
Self Esteem ◽  
Point Of View ◽  
The Other ◽  
Self Concept ◽  
High Ability ◽  
Self Image ◽  
Other Hand

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.

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