Mating increases the synthetic activity of the neurosecretory caudodorsal cells of Helisoma duryi (Mollusca: Pulmonata)

1989 ◽  
Vol 67 (10) ◽  
pp. 2363-2367 ◽  
Author(s):  
S. T. Mukai ◽  
A. S. M. Saleuddin
Keyword(s):  
Light Microscope ◽  
Egg Laying ◽  
Microscope Level ◽  
Synthetic Activity ◽  
Leucine Incorporation ◽  
Light Microscope Level ◽  
Cerebral Ganglia ◽  
Helisoma Duryi

In Helisoma duryi, virgin snails lay significantly fewer eggs than mated snails. It is generally accepted that in basommatophoran pulmonates, the neurosecretory caudodorsal cells located in the cerebral ganglia produce a hormone that regulates egg laying. The synthetic activity of the caudodorsal cells in Helisoma has been measured in vitro and in vivo using tritiated leucine. Virgin and castrated snails (reproductively inactive) showed significantly reduced levels of [3H]leucine incorporation compared with first-mated snails (24 and 48 h postmating). This increase in synthetic activity following mating was corroborated by autoradiography at the light microscope level which localized transport of caudodorsal cell neurosecretory proteins to the cerebral commissure, the neurohaemal area. Mating triggers an increase in synthetic activity of the caudodorsal cells.

Neuronal sites of action of a neurosecretory peptide, egg-laying hormone, in Aplysia californica

1980 ◽  
Vol 43 (2) ◽  
pp. 499-519 ◽  
Author(s):  
D. K. Stuart ◽  
F. Strumwasser
Keyword(s):  
Nervous System ◽  
Neuronal Activity ◽  
Feeding Activity ◽  
Gel Filtration ◽  
Egg Laying ◽  
Cerebral Ganglia ◽  
Buccal Ganglia ◽  
Sites Of Action

1. Egg-laying hormone (ELH) is a polypeptide of about 4,500 mol wt synthesized in the bag cell neurons of the abdominal ganglion of Aplysia. We studied the effects of ELH on the neuronal activity of the attached head ganglia (buccal, cerebral, pleural, and pedal), on the isolated buccal ganglia, as well as on feeding in intact Aplysia. 2. Starved animals (n = 7) injected with crude extract containing ELH stopped eating algae at 17 +/- 4 min and their eggs first appeared at 29 +/- 4 min after injection at 20 degrees C. This cessation of eating is significant when compared to the seven controls (P less than 0.01). These data clearly indicate that a suppression of feeding activity occurs before the appearance of eggs. 3. ELH applied to the paired buccal ganglia in vitro activates a pair of neurons into a tonic pacemaker mode (approximately 1 spike/s). This activation also occurs in a high-magnesium, zero calcium solution that blocks chemical synapses. The time for the full appearance of this activity in vitro correlates well with the time for suppression of feeding in vivo. Each of these neurons has an ipsilateral axon in buccal nerve 3. The neuron has been identified by intracellular recording. 4. ELH increases the rate of firing of a second pair of buccal neurons, each with an ipsilateral axon in the cerebrobuccal connective. 5. ELH, when applied to the attached head ganglia, causes large bursts of neuronal activity in pedal nerves to the foot and increased activity in the nerve to the penis; the relevant neurons remain to be identified. 6. These in vitro effects were produced by ELH partially purified from bag cell cluster homogenates using ammonium sulfate precipitation followed by anion exchange and gel filtration chromatography or by ELH released from activated bag cells in isolated abdominal ganglia and then purified by gel filtration. The isolated buccal ganglia effects have been confirmed with fully purified ELH. 7. The ELH effects on the in vitro nervous system support the hypothesis that ELH in vivo acts directly on the nervous system to suppress feeding activity, controlled by the buccal and cerebral ganglia. ELH may also produce characteristic movements of the head during egg laying, controlled probably by the pedal and cerebral ganglia.

Studies on the in vitro formation of periostracum in Helisoma duryi: the influence of the dorsal epithelium on calcium incorporation

1984 ◽  
Vol 62 (6) ◽  
pp. 1177-1180 ◽  
Author(s):  
S. C. Kunigelis ◽  
A. S. M. Saleuddin
Keyword(s):  
Epithelial Tissue ◽  
Whole Brain ◽  
Fast Growing ◽  
Cerebral Ganglia ◽  
Helisoma Duryi ◽  
Shell Deposition ◽  
Slow Growing

Mantle collar tissue was found to produce periostracum when placed in vitro. The rate of shell deposition in vivo was reflected in the in vitro rate of periostracum formation. The addition of whole brain from fast-growing donors to mantle collar from slow-growing animals was found to increase the amount of periostracum produced in vitro. This effect was further enhanced by removing the cerebral ganglia lateral lobes prior to incubation. The presence of dorsal epithelial tissue was found to increase the incorporation of calcium into periostracum formed in vitro.

The structure and development of the pigmented retinal clone

1975 ◽  
Vol 53 (5) ◽  
pp. 560-570 ◽  
Author(s):  
Bruce J. Crawford
Keyword(s):  
Epithelial Cells ◽  
Light Microscope ◽  
Microscope Level ◽  
Light Microscope Level ◽  
Differentiated Cells ◽  
Cytological Changes ◽  
Pass Through ◽  
Flocculent Material ◽  
Clone Cells

Cytological changes during growth and differentiation of chick pigmented epithelial cells in clonal culture are described at the light microscope level. Initially the cells are squamous and unpigmented. By 3 weeks, cells in the center of the colonies are highly differentiated, i.e. they are polygonal in shape and densely pigmented. During differentiation, cells in the center of the colony pass through a series of morphological stages comparable to those seen from the edge to the center of a 3-week-old clone. Cells in the inner two zones of a differentiated colony resemble stages found during differentiation in vivo. Those in the outer two zones appear to have no morphological counterparts in the intact animal.Extracellular materials are abundant in the stratified zone of the colony. These exhibit staining properties similar to those of acid mucopolysaccharides found in the developing retina. Vacuoles containing a flocculent material appear within the differentiated cells of colonies older than 2.5 weeks. Later, some of these vacuoles disappear and flocculent material is found between the cells and the plate. The possible significance of these observations is discussed.

CONTRIBUTION TO THE EXISTENCE OF REGULATORY MECHANISMS AT THE ADRENAL LEVEL

1972 ◽  
Vol 70 (4) ◽  
pp. 741-757
Author(s):  
Otto Linèt
Keyword(s):  
Orotic Acid ◽  
Adrenal Glands ◽  
Actinomycin D ◽  
Delay Period ◽  
Regulatory Mechanisms ◽  
Leucine Incorporation ◽  
Total Period ◽  
Free Media

ABSTRACT Rat adrenal glands atrophied by the administration of cortisol acetate in vivo were used as a model for the study of early metabolic processes occurring in vitro. Atrophied adrenals incubated in the presence of 14C-leucine incorporated subnormal quantities of this amino acid per mg of protein for the first 120 min. When the incubation lasted for a total period of 180 or 240 min a supranormal rise in the 14C-leucine incorporation was observed. Similar changes occurred with some delay with regard to corticosterone production as expressed per 100 mg of tissue. No differences in 14C-leucine incorporation were observed between the control and atrophied adrenals in vivo. Homogenates from atrophied glands incorporated 14C-leucine to a greater extent than the control homogenates. The in vitro incorporation of 14C-orotic acid into the RNA was also higher in atrophied adrenals. The in vitro use of actinomycin D, cycloheximide and amphenone indicated that corticosterone production depended on the incorporation of 14C-leucine. The addition of cortisol to the incubation media markedly decreased the enhancement of 14C-lysine incorporation into the protein of atrophied adrenals. These, as well as additional results suggest rebound phenomena: once atrophic adrenals are transferred to cortisol-free media, reparative processes begin after a delay period. Such phenomena seem to be mediated by regulatory mechanisms at the adrenal level.

Reproduction in Aplysia californica: correlations between egg laying in vivo and egg release in vitro

1980 ◽  
Vol 58 (11) ◽  
pp. 2163-2166 ◽  
Author(s):  
F. Edward Dudek ◽  
Amd Bonnie Soutar ◽  
Stephen S. Tobe
Keyword(s):  
Aplysia Californica ◽  
Egg Laying ◽  
Previous Episode ◽  
Laboratory Conditions ◽  
Release In Vitro

Aspects of egg laying by isolated Aplysia californica and egg release from ovotestis fragments were compared under laboratory conditions. The volume of eggs laid per episode increased as a function of time since the previous episode of egg laying. Egg output in vivo and egg release in vitro were maximal in autumn and minimal in spring, but a factor in the parietovisceral ganglion evoked egg release from ovotestis fragments throughout the year. These data are consistent with previous studies which have suggested that the effects of season and egg-laying history on egg laying involve substantial changes in the ovotestis.

Use of an in Vitro Protein Synthesizing System to Test the Mode of Action of Chloracetamides

Weed Science ◽  
1980 ◽  
Vol 28 (3) ◽  
pp. 334-340 ◽  
Author(s):  
Luanne M. Deal ◽  
J. T. Reeves ◽  
B. A. Larkins ◽  
F. D. Hess
Keyword(s):  
Protein Synthesis ◽  
Sand Culture ◽  
Leucine Incorporation ◽  
Insoluble Protein ◽  
In Vitro System ◽  
A Cell ◽  
Protein Incorporation ◽  
Vitro Protein

The effects of chloracetamides on protein synthesis were studied both in vivo and in vitro. Four chloracetamide herbicides, alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], CDAA (N–N-diallyl-2-chloroacetamide), and propachlor (2-chloro-N-isopropylacetanilide) were tested for inhibition of [3H]-leucine incorporation into protein. Incorporation of3H-leucine into trichloroacetic acid (TCA)-insoluble protein was inhibited in oat (Avena sativaL. ‘Victory’) seedlings grown in sand culture and treated 12 h at 1 × 10−4M with these chloracetamides. The herbicides were also tested in a cell-free protein synthesizing system containing polyribosomes purified from oat root cytoplasm. These herbicides had no effect on the rates of polypeptide elongation nor on the synthesis of specific polypeptides when herbicides (1 × 10−4M) were added directly to the system. Polypeptide formation was inhibited 89% when 1 × 10−4M cycloheximide was added during translation. Cytoplasmic polyribosomes were isolated from oat roots treated 12 h with 1 × 10−4M herbicide. Translation rates and products were not altered when these polyribosomes were added to the in vitro system. Protein synthesis is inhibited when tested in an in vivo system; however, the inhibition does not occur during the translation of mRNA into protein.

scholarly journals Distribution of Intravenously Administered Gold Nanoparticles at the Light Microscope Level

2011 ◽  
Vol 25 (S1) ◽  
Author(s):  
Diana C Haines ◽  
Stephen Stern ◽  
Jennifer Hall ◽  
Anil Patri ◽  
Scott McNeil
Keyword(s):  
Gold Nanoparticles ◽  
Light Microscope ◽  
Microscope Level ◽  
Light Microscope Level

scholarly journals Some biochemical effects of triamcinolone acetonide on rat liver and muscle

1970 ◽  
Vol 116 (3) ◽  
pp. 349-355 ◽  
Author(s):  
R. F. Peters ◽  
M. C. Richardson ◽  
Margaret Small ◽  
A. M. White
Keyword(s):  
Amino Acids ◽  
Triamcinolone Acetonide ◽  
Time Course ◽  
Muscle Protein ◽  
Specific Radioactivity ◽  
Synthetic Activity ◽  
Tissue Homogenate ◽  
Glycogen Concentration

1. The powerful anti-inflammatory glucocorticoid triamcinolone acetonide, administered to rats at 20 and 2.5mg/kg, leads to a decrease in the incorporation in vivo of [3H]uridine and [32P]orthophosphate into hind-limb skeletal muscle. 2. At the higher dose, this decrease in the rate of incorporation of precursors into RNA precedes a decrease in the incorporating ability of muscle ribosomes, which commences about 4–5h after drug administration, but is unaccompanied by any changes in the concentration of tissue ATP or free amino acids. 3. The ribosomal dysfunction extends to polyribosomes, which can only be successfully isolated from the muscle of triamcinolone-treated animals after the addition of α-amylase to the tissue homogenate to remove glycogen. 4. The specific radioactivity of muscle protein labelled in vivo with 14C-labelled amino acids does not decrease progressively after triamcinolone administration. After 2h there is an apparent stimulation of incorporation which leads to an overall discrepancy between measurements of protein-synthetic activity made in vivo and in vitro. 5. There is a significant increase in muscle-glycogen concentration between 8 and 12h after the administration of triamcinolone acetonide (20mg/kg), although a significant decrease occurs after 4h. The fall in glycogen concentration may be due to a decrease in the rate of synthesis of protein essential for glucose uptake into the tissues. 6. As judged by (a) incorporation of 14C-labelled amino acids into protein, (b) [3H]uridine and [32P]-orthophosphate incorporation into RNA, (c) the rate of induction of tryptophan pyrrolase and (d) changes in the pool sizes of taurine and tryptophan, the responses in liver followed the same time-course as those in muscle after administration of the drug.

Histochemical characteristics of the metacercarial cyst wall of Gynaecotyla adunca

1995 ◽  
Vol 69 (3) ◽  
pp. 223-228
Author(s):  
J. Lee ◽  
M.A. Medlin ◽  
S.T. Dunn
Keyword(s):  
Outer Layer ◽  
Cyst Wall ◽  
Light Microscope ◽  
Structural Modification ◽  
Microscope Level ◽  
Histochemical Analysis ◽  
Light Microscope Level ◽  
Metacercarial Cyst

AbstractThe cyst wall of the metacercaria of Gynaecotyla adunca (Microphallidae: Digenea) was subjected to comprehensive histochemical analysis. At the light microscope level, a uniformly thick, bipartite cyst wall, probably wholly of parasite origin, was evident. Structural modification of the cyst wall to provide an escape aperture was not apparent. The thicker, inner layer was comprised of phospholipid and glyco- and/or mucoproteins, possibly similar in structure to collagen. The outer layer was highly proteinaceous and contained additional amounts of acidic and neutral mucosubstances. The results are discussed in the context of previous observations regarding the excystment requirements of this microphallid species.

scholarly journals LYSOSOMES IN RAT THORACIC DUCT LYMPHOCYTES FRACTIONATED BY ZONAL CENTRIFUGATION

1973 ◽  
Vol 59 (1) ◽  
pp. 177-184 ◽  
Author(s):  
William E. Bowers
Keyword(s):  
Thoracic Duct ◽  
Light Microscope ◽  
Cathepsin D ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Differential Centrifugation ◽  
Acid Hydrolases ◽  
Fractionation Method

A method of zonal centrifugation was developed which separates rat thoracic duct lymphocytes (TDL) mainly according to size. The validity of the fractionation method was supported by light microscope observations, Coulter Counter sizing, and in vivo and in vitro labeling of lymphocytes. The distributions of lysosomal acid hydrolases in TDL fractionated by zonal centrifugation are similar to the distribution obtained for the cells. This result indicates that the large lymphocyte is not the sole bearer of either lysosomes or the large amount of soluble cathepsin D found in homogenates of TDL. Both reside mainly in small lymphocytes. This point was clearly established by fractionating homogenates of purified small lymphocytes by means of differential centrifugation and isopycnic density gradient centrifugation.

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