scholarly journals The Determination of Characters at Metamorphosis in Rhodnius Prolixus (Hemiptera)

1940 ◽  
Vol 17 (2) ◽  
pp. 201-223 ◽  
Author(s):  
V. B. WIGGLESWORTH
Keyword(s):  
Critical Period ◽  
Fat Body ◽  
Corpus Allatum ◽  
Adult Type ◽  
Histological Changes ◽  
Short Time ◽  
The Brain ◽  
New Hypothesis ◽  
Partial Reversion

Nymphs of Rhodnius decapitated 24 hr. after feeding can be induced to moult by implanting into the abdomen the dorsal region of the protocerebrum removed from other nymphs during the critical period. Implantation of other parts of the brain, of the corpus allatum, and of fat body from the same insects did not cause moulting. The presence of large nerve cells with fuchsinophil inclusions discovered by Hanström in this region of the brain has been confirmed. The histological changes in the epidermis of the abdomen and the distribution of mitoses at an imaginal moult and at a nymphal moult have been compared. During a nymphal moult mitoses occur all over the tergites; during an imaginal moult they are largely confined to the intersegmental membranes and the periphery of the abdomen, and there is a more extensive breakdown of existing cells. If 5th stage nymphs in the course of moulting to become adults receive "inhibitory hormone" from young nymphs, they may be caused to "switch over" to nymphal development. Such a "switch over" soon becomes impossible for the most specialized structures of the adult; other structures follow in turn; but the general cuticle of the tergites may still be influenced up to a short time before it is due to be laid down. The various faculties of a given cell can become determined to some extent independently of one another. Isolated fragments of cuticle and epidermis from Rhodnius adults may be induced to moult, more than once, by transplantation to young moulting nymphs. Decapitated Cimex adults may be caused to moult again if they receive blood from moulting Rhodnius nymphs; but they lay down a normal cuticle with bristles only if they have become adult very recently. Decapitated Rhodnius adults may be caused to moult again if they receive blood from two moulting 5th stage nymphs. They lay down a cuticle of normal adult type even when they have been adults for several months. The old skin is digested up to the level of the exocuticle. If such moulting adults are provided with inhibitory hormone from the corpus allatum of young nymphs, they show a partial reversion to nymphal characters when they moult. This change probably does not extend to the most specialized imaginal structures; but the pigmentation and the structure of the general cuticle, and of the bristles it carries, may become partially nymphal again. The "determination" of imaginal or nymphal characters thus takes place at different times in different organs. And for some characters, at least, such determination is not irrevocable. In the light of these results a new hypothesis is put forward to explain the action of the inhibitory hormone in controlling metamorphosis. This work was begun during a stay of three months in Berlin-Dahlem as the guest of the Kaiser-Wilhelm Gesellschaft, to whom my thanks are due. Throughout this stay I was indebted to Prof. A. Kühn and his colleagues at the Kaiser-Wilhelm Institut für Biologie for every assistance and for much stimulating discussion.

scholarly journals The Thoracic Gland in Rhodnius Prolixus (Hemiptera) and Its Role in Moulting

1952 ◽  
Vol 29 (4) ◽  
pp. 561-570
Author(s):  
V. B. WIGGLESWORTH
Keyword(s):  
Critical Period ◽  
Fat Body ◽  
Secretory Activity ◽  
Rhodnius Prolixus ◽  
Diffuse Layer ◽  
Moulting Hormone ◽  
The Brain

The ‘moulting hormone’ in Rhodnius is composite. The factor secreted in the dorsum of the brain activates a gland in the thorax which then produces the factor initiating growth and moulting. Implantation of the thoracic gland will induce moulting in the isolated abdomen; implantation of the brain is effective only if the thorax is intact. This system agrees with that described in Lepidoptera and Diptera and is probably widespread in insects. The thoracic gland in Rhodnius consists of a loose network of very large cells, richly supplied with tracheae, spread as a single diffuse layer over the surface of the inner lobes of the thoracic fat-body. These cells go through a cycle of secretory activity which reaches its peak during the critical period. They break down and disappear within 2 days after the insect becomes adult. The adult Rhodnius is caused to moult by implantation of the thoracic gland from a moulting larva; it is not caused to moult by implantation of the brain.

Humoral Regulation of the Cerebral Neurosecretory System of Rhodnius Prolixus (Stal.) During Growth and Moulting

1973 ◽  
Vol 58 (1) ◽  
pp. 177-187
Author(s):  
C. G. H. STEEL
Keyword(s):  
Critical Period ◽  
Endocrine System ◽  
Feedback Regulation ◽  
Neurosecretory Cells ◽  
Corpus Allatum ◽  
Neurosecretory System ◽  
Neurosecretory Material ◽  
Before And After ◽  
Cytological Changes ◽  
The Brain

1. In normal fifth instar Rhodnius the cytological changes occurring in the medial neurosecretory cells (MNC) of the brain are very different before and after the ‘critical period’ for decapitation. 2. When a decapitated insect which has reached the ‘critical period’ (8 days after feeding) is joined in parabiosis to an insect with an intact cerebral endocrine system and which has not yet reached the ‘critical period’ (1 day after feeding) the MNC of the younger insect are induced to switch over from their normal sequence of cytological changes to those characteristic of the older insect. The induced changes do not occur in normal insects of the same age or in insects joined in parabiosis to others of the same age. 3. The nature of the changes indicates that release of stainable neurosecretory material is inhibited and its synthesis stimulated by the older insect. It is inferred that the haemolymph of insects which have reached the ‘critical period’ contains a factor which induces in the MNC an inhibition of release and a stimulation of synthesis. These are the events which occur in the MNC of normal insects at the critical period. 4. Considerable circumstantial evidence suggests that the factor is ecdysone. It may act either directly on the brain or on the corpus allatum. Its contribution to a feedback regulation of the endocrine system controlling growth and moulting is discussed.

Memoirs: The Physiology of Ecdysis in Rhodnius Prolixus (Hemiptera). II. Factors controlling Moulting and ‘Metamorphosis’

1934 ◽  
Vol s2-77 (306) ◽  
pp. 191-222
Author(s):  
V. B. WIGGLESWORTH
Keyword(s):  
Critical Period ◽  
Secretory Activity ◽  
Rhodnius Prolixus ◽  
Corpus Allatum ◽  
Whole Process ◽  
Definite Interval ◽  
Moulting Hormone ◽  
Moulting Cycle ◽  
The Brain ◽  
Complete Metamorphosis

The five nymphal stages of Rhodnius prolixus are more or less alike. The adult differs markedly from the nymphs. There are thus two phenomena to be considered: simple moulting and moulting coupled with metamorphosis. 1. Causation of Moulting. Moulting occurs at a definite interval after feeding, only one meal being necessary in each stage. There is a ‘critical period’ in the moulting cycle (about 7 days after feeding in the fifth nymph, about 4 days in the earlier nymphs) and removal of the head of the insect before this period prevents moulting. The critical period corresponds with the time when mitotic divisions in the epidermis begin. The blood of insects that have passed the critical period contains a factor or hormone which will induce moulting in insects decapitated soon after feeding. It is suggested that this moulting hormone may be secreted by the corpus allatum, since the cells of this gland show signs of greatest secretory activity during the critical period. Stretching of the abdominal wall provides the stimulus which causes secretion of the moulting hormone. This stimulus is conveyed by nerves to the brain: moulting is prevented by section of the nerve-cord in the prothorax. Section of the nerves between the brain and the corpus allatum appears to prevent moulting; but these experiments were inconclusive. Insects sharing the same blood moult simultaneously. The whole process of growth must therefore be co-ordinated by chemical means; the factors concerned being produced presumably by the growing cells themselves. 2. Causation of Metamorphosis. If fourth or even first nymphs, decapitated soon after feeding, receive the blood from moulting fifth nymphs, they suffer a precocious metamorphosis and develop adult characters. Metamorphosis is therefore brought about by chemical differences in the blood. If fifth nymphs decapitated soon after feeding receive blood from moulting fourth nymphs, they also moult; showing that the moulting factor is the same at all stages. The absence of metamorphosis in normal nymphs before the fifth stage must therefore be due to an inhibitory factor or hormone in the blood. This is proved by the fact that if a fifth nymph decapitated soon after feeding receives the blood from a moulting fourth nymph (not deprived of its head) it develops characters much more like those of a nymph than an adult. The inhibitory hormone is normally produced in such small quantities that simple dilution of the blood of a moulting fourth nymph with that of another fourth nymph (decapitated soon after feeding) causes them both to suffer metamorphosis. The head is necessary for the secretion of the inhibitory hormone. This hormone seems to be secreted after the moulting hormone. Thus if series of fourth, third, second, or first nymphs are decapitated around the critical period, some of them show more or less complete metamorphosis. Others show characters intermediate between those of nymphs and adults. The bearing of these results on the phenomena of diapause and prothetely is discussed.

VASCULAR CONNECTIVE TISSUE UNDER THE INFLUENCE OF THYROXINE

1961 ◽  
Vol 36 (2) ◽  
pp. 197-211 ◽  
Author(s):  
lb Lorenzen
Keyword(s):  
Connective Tissue ◽  
Vessel Wall ◽  
Aortic Wall ◽  
Calcium Content ◽  
Sodium Sulphate ◽  
Collagen Content ◽  
Histological Changes ◽  
Hexosamine Content ◽  
Healing Processes

ABSTRACT Biochemical and histological changes in the aortic wall of rabbits were demonstrated following injection of epinephrine and l-thyroxine during 2 weeks. The widespread gross and microscopic changes were accompanied by an increase in hexosamine content and uptake of 35S labeled sodium sulphate, and an increased calcium content, whereas the collagen content, assessed by determination of hydroxyproline, was reduced. Comparison with the effect of epinephrine injections alone showed that thyroxine intensified the damaging effect of epinephrine on the vessel wall and induced more pronounced mucopolysaccharide changes in the aortic wall, presumably acting as a link in the healing processes.

High Frequency Vibration of Worst Ear Lobule induced short period of Rapid Inhibition of any Cancer Activity including Advanced Terminal Cancers, Most Malignant Brain Tumor "Glioblastoma" as well as Cancer of Lung, Breast & Gastrointestinal Cancers particularly Pancreatic Cancer.

2020 ◽  
Vol 44 (3) ◽  
pp. 241-249
Author(s):  
Yoshiaki Omura
Keyword(s):  
Pancreatic Cancer ◽  
Vitamin D3 ◽  
High Frequency ◽  
Optimal Dose ◽  
High Frequency Stimulation ◽  
Frequency Stimulation ◽  
Short Time ◽  
The Brain ◽  
Cancer Activity ◽  
Stimulation Of

While a visiting Professor at the University of Paris, VI (formerly Sorvonne) more than 40 years ago, the Author became very good friends with Dr. Paul Nogier who periodically gave seminars and workshops in Paris. After the author diagnosed his cervical problem & offered him simple help, Dr. Nogier asked the Author to present lectures and demonstrations on the effects of ear stimulation, namely the effects of acupuncture & electrical stimulation of the ear lobules. It is only now, in 2019 that we have discovered 2–5 minute high frequency stimulation of the ear lobule inhibits cancer activity for 1– 4 hours post stimulation. Although the procedure is extremely simple. First take optimal dose of Vitamin D3, which has the most essential 10 unique beneficial factors required for every human cell activity. Next, apply high frequency stimulation to ear lobule while the worst ear lobule is held by all fingers with vibrator directly touching the surface of the worst ear lobule, preferably after patient repeatedly takes optimal dose of Vitamin D3. When the worst ear lobule is held between thumb & index fingers and applying mechanical stimulation of 250 ~ 500 mechanical vibration/second for 2 ~ 5 minutes using an electrical vibrator, there is rapid disappearance of cancer activity in both the brain and rest of the body for short time duration 1 ~ 4 hours. The effect often increases by additional pressure by holding fingers. As of May 2019, the Author found that many people from various regions of the world developed early stages of multiple cancers. For evaluation of this study, U. S. patented Bi-Digital O-Ring Test (BDORT) was used which was developed by the Author while doing his Graduate experimental physics research at Colombia University. BDORT was found to be most essential for determining the beneficial effects as well as harmful effects of any substance or treatment. Using BDORT, Author was the first to recognize severe increasing mid-backache was an early sign of pancreatic cancer of President of New York State Board of Medicine after top pain specialists failed to detect the cause after 3 years of effort, while the BDORT showed early stages of cancer whereas conventional X-Ray of the pancreas did not show any cancer image until 2 months after Author detected with BDORT. For example, the optimal dose of the banana is usually about 2.0 - 2.5 millimeters cross section of the banana. A whole banana is more than 50 ~ 100 times the optimal dose. Any substance eaten in more than 25 times of its optimal dose becomes highly toxic and creates DNA mutations which can cause multiple malignancies in the presence of strong electro-magnetic field. With standard medication given by doctor, patients often become sick and they are unable to reduce body weight, unless medication is reduced or completely stopped. When the amount of zinc is very high, DNA often becomes unstable and multiple cancers can grow rapidly in the presence of strong electromagnetic field. Large amount of Vitamin C from regular orange or orange juice inhibit the most important Vitamin D3 effects. At least 3 kinds of low Vitamin C oranges will not inhibit Vitamin D3. Since B12 particularly methyl cobalamin which is a red small tablet is known to improve brain circulation very significantly we examined its effect within 20 seconds of oral intake we found the following very significant changes. Acetylcholine in both sides of the brain often increases over 4,500 ng. Longevity gene Sirtuin 1 level increases significantly for short time of few hours. Thymosin α1 and Thymosinβ4 both increase to over 1500 ng from 20 ng or less.

Simultaneous Determination of Imatinib and N-Desmethyl Imatinib in Rat Plasma and Tissues Using LC-MS/MS

2019 ◽  
Vol 15 (2) ◽  
pp. 121-129
Author(s):  
Zhi Rao ◽  
Bo-xia Li ◽  
Yong-Wen Jin ◽  
Wen-Kou ◽  
Yan-rong Ma ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Oral Administration ◽  
Parent Drug ◽  
Gradient Elution ◽  
Biological Tissues ◽  
Rat Plasma ◽  
Running Water ◽  
Liver And Kidney ◽  
The Brain

Background: Imatinib (IM) is a chemotherapy medication metabolized by CYP3A4 to Ndesmethyl imatinib (NDI), which shows similar pharmacologic activity to the parent drug. Although methods for determination of IM and/or NDI have been developed extensively, only few observations have been addressed to simultaneously determine IM and NDI in biological tissues such as liver, kidney, heart, brain and bone marrow. Methods: A validated LC-MS/MS method was developed for the quantitative determination of imatinib (IM) and N-desmethyl imatinib (NDI) from rat plasma, bone marrow, brain, heart, liver and kidney. The plasma samples were prepared by protein precipitation, and then the separation of the analytes was achieved using an Agilent Zorbax Eclipse Plus C18 column (4.6 × 100 mm, 3.5 µm) with gradient elution running water (A) and methanol (B). Mass spectrometric detection was achieved by a triplequadrupole mass spectrometer equipped with an electrospray source interface in positive ionization mode. Results: This method was used to investigate the pharmacokinetics and the tissue distributions in rats following oral administration of 25 mg/kg of IM. The pharmacokinetic profiles suggested that IM and NDI are disappeared faster in rats than human, and the tissue distribution results showed that IM and NDI had good tissue penetration and distribution, except for the brain. This is the first report about the large penetrations of IM and NDI in rat bone marrow. Conclusion: The method demonstrated good sensitivity, accuracy, precision and recovery in assays of IM and NDI in rats. The described assay was successfully applied for the evaluation of pharmacokinetics and distribution in the brain, heart, liver, kidney and bone marrow of IM and NDI after a single oral administration of IM to rats.

scholarly journals Expression Level of Mature miR172 in Wild Type and StSUT4-Silenced Plants of Solanum tuberosum Is Sucrose-Dependent

2021 ◽  
Vol 22 (3) ◽  
pp. 1455
Author(s):  
Varsha Garg ◽  
Aleksandra Hackel ◽  
Christina Kühn
Keyword(s):  
Solanum Tuberosum ◽  
Wild Type ◽  
Potato Plants ◽  
Mature Leaves ◽  
In Vitro Plantlets ◽  
Long Time ◽  
Short Time ◽  
Cut Leaves

In potato plants, the phloem-mobile miR172 is involved in the sugar-dependent transmission of flower and tuber inducing signal transduction pathways and a clear link between solute transport and the induction of flowering and tuberization was demonstrated. The sucrose transporter StSUT4 seems to play an important role in the photoperiod-dependent triggering of both developmental processes, flowering and tuberization, and the phenotype of StSUT4-inhibited potato plants is reminiscent to miR172 overexpressing plants. The first aim of this study was the determination of the level of miR172 in sink and source leaves of StSUT4-silenced as well as StSUT4-overexpressing plants in comparison to Solanum tuberosum ssp. Andigena wild type plants. The second aim was to investigate the effect of sugars on the level of miRNA172 in whole cut leaves, as well as in whole in vitro plantlets that were supplemented with exogenous sugars. Experiments clearly show a sucrose-dependent induction of the level of mature miR172 in short time as well as long time experiments. A sucrose-dependent accumulation of miR172 was also measured in mature leaves of StSUT4-silenced plants where sucrose export is delayed and sucrose accumulates at the end of the light period.

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