Exchanges of Sodium and Potassium in Mosquito Larvae

1953 ◽  
Vol 30 (1) ◽  
pp. 79-89 ◽  
Author(s):  
J. A. RAMSAY
Keyword(s):  
Aedes Aegypti ◽  
External Medium ◽  
The Body ◽  
Malpighian Tubules ◽  
Mosquito Larvae ◽  
The Face ◽  
Tubule Fluid ◽  
Sodium And Potassium

1. The movements of sodium and potassium through the body and their exchanges between the body and the external medium have been studied in the larva of Aedes aegypti L. 2. Briefly, both elements enter the body via the anal gills, are excreted by the Malpighian tubules and can be absorbed from the tubule fluid in the rectum. When either element is present in the medium to excess its concentration in the tubule fluid is increased and the extent of its absorption in the rectum is decreased. 3. Under all conditions the concentration of potassium in the tubule fluid is greater than its concentration in the haemolymph, and the concentration of sodium is less. There is a circulation of potassium from haemolymph to tubule, to rectum or midgut and so back to haemolymph. 4. The composition of the haemolymph in respect of sodium and potassium is remarkably constant in the face of changes in the medium. 5. The volume of the larva appears to be regulated by a nervous mechanism. If the volume is increased peristaltic waves pass down the intestine more frequently and more fluid is voided through the anus.

Studies on the Physiology of Ascaris Lumbricoides

1952 ◽  
Vol 29 (1) ◽  
pp. 22-29
Author(s):  
A. D. HOBSON ◽  
W. STEPHENSON ◽  
A. EDEN
Keyword(s):  
Ascaris Lumbricoides ◽  
Body Fluid ◽  
External Medium ◽  
Chloride Concentration ◽  
The Body ◽  
Considerable Proportion ◽  
Limiting Factor ◽  
Inorganic Cations ◽  
Sodium And Potassium ◽  
Total Concentrations

The results obtained in this investigation are admittedly not as extensive as is desirable but they allow certain conclusions to be drawn. 1. The sodium and potassium contents of the body fluid of Ascaris lumbricoides are somewhat variable, but these variations do not seem to be dependent upon those of the external medium. 2. The calcium and magnesium contents of the body fluid are relatively constant and are not affected by those of the external medium. 3. The chloride concentration of the body fluid is closely related to and always remains lower than that of the external medium. 4. As shown in Table 2, there is a large gap between the total concentrations of inorganic cations and anions in the intestinal fluid of the pig. Presumably a considerable proportion of the inorganic cations are combined with organic anions, at present undetermined. Exposing the worms to saline media composed of chloride caused a large rise in the internal chloride concentration. This may well be a limiting factor in the life of the animals in such media, and the next step forward would seem to be the fuller analysis of the environment to which they are normally exposed.

Regulation of rectal secretion in saline-water mosquito larvae living in waters of diverse ionic composition

1977 ◽  
Vol 66 (1) ◽  
pp. 83-96 ◽  
Author(s):  
T. J. Bradley ◽  
J. E. Philips
Keyword(s):  
Chemical Composition ◽  
External Medium ◽  
Saline Water ◽  
Ionic Composition ◽  
Malpighian Tubules ◽  
Fluid Composition ◽  
Mosquito Larvae ◽  
Major Site ◽  
Osmotic Concentration ◽  
Anal Papillae

1. Larvae of the saline-water mosquito Aedes campestris were adapted to three waters, all having an osmotic concentration of 700 mOsm, but differing in ionic rations. The (Na+Mg) SO4 medium was much moretoxic than the NAHCO3 or the NaCl media. 2. Ionic and osmotic concentrations of haemolymph and rectal secretion were measured in larvae adapted to all three media. The ratio of ionic concentrations in the rectal secretion reflected those in the external medium to which the larvae had been adapted, with the exception of SO42-, which was possibly replaced by HCO3-in the secretion. These differences in rectal fluid composition persisted even though all ligated recta were bathed in the same artificial haemolymph. 3. The Malpighian tubules were found to be the major site of SO42- excretion. In media containing high levels of NA+, Mg2+, K+, Cl- and HCO3-, the rectum secreted a hyperosmotic fluid containing these ions at concentrations several times greater than those found in the haemolymph. 4. These data provide the basis for speculation on the functioning of anal papillae in waters of diverse chemical composition.

The rectal complex in the larvae of Lepidoptera

1976 ◽  
Vol 274 (932) ◽  
pp. 203-226 ◽  
Keyword(s):  
Tidal Flow ◽  
Basic Mechanism ◽  
Pieris Brassicae ◽  
Body Cavity ◽  
The Body ◽  
Malpighian Tubules ◽  
Salt Balance ◽  
Entry Points ◽  
Perinephric Space ◽  
Tubule Fluid

In the so-called ‘cryptonephric’ condition of the excretory system in insects the distal ends of the Malpighian tubules are closely applied to the rectum and enclosed with it in a special chamber, the perinephric space, separated from the rest of the body cavity by the perinephric membrane. The term ‘rectal complex’ refers to this association of tubules and rectum, which is found in the larvae (but not in the adults) of most Lepidoptera. In the mealworm (Coleoptera) the rectal complex has notable ability to remove water from the faeces, but this ability is not conspicuously developed in the larvae of the two species of Lepidoptera here studied: Pieris brassicae and Manduca sexta . On the other hand these larvae have notable ability to maintain salt balance under heavy dietary loading, and in this the rectal complex plays an important part. A study of salt balance in more detail has shown that more sodium can be eliminated in the faeces than enters the rectal complex from the intestine. Consideration of other possible routes of entry points strongly to the Malpighian tubules. Superimposed upon a net flow of tubule fluid out of the rectal complex there is a tidal flow, brought about by the rectal musculature and amplified by dilatations of the cryptonephric tubules, which could bring in fluid from the free tubules and afford opportunity for the uptake of salts. Evidence is presented in support of this view. This tidal flow of tubule fluid and uptake of salts could be the basis of the build-up of high osmolarity in the perinephric fluid and could contribute to the removal of water from the faeces. It could also be the basic mechanism in the mealworm, the leptophragmal mechanism being superimposed upon it.

A Study of the Malpighian Tubules of the Pill Millipede, Glomeris marginata (Villers)

1974 ◽  
Vol 60 (1) ◽  
pp. 29-39
Author(s):  
PATRICIA ANNE FARQUHARSON
Keyword(s):  
Osmotic Pressure ◽  
Electrical Potential ◽  
Malpighian Tubules ◽  
Potassium Ions ◽  
Electrical Potential Difference ◽  
Ion Concentrations ◽  
Fluid Production ◽  
Tubule Fluid ◽  
Sodium And Potassium ◽  
Tubule Wall

1. Isolated Malpighian tubules of Glomeris produce fluid which is identical to the bathing media with respect to ion concentrations and osmotic pressure. 2. The tubules secrete normally in a potassium-free Ringer, but they cease to function in a sodium-free Ringer. 3. The rate of fluid production is dependent on the availability of sodium ions, but it is also inhibited by higher concentrations (25 mM/l of potassium ions. 4. Throughout a wide variation in concentrations of sodium and potassium ions in the bathing Ringer, the concentrations of these ions in the tubule fluid are the same as their concentrations in the Ringer. 5. Fluid production by the tubules of Glomeris is inhibited by ouabain at a concentration of 5x10-6M/l or greater. 6. The rate of fluid production varies inversely with the osmotic pressure, and the secreted fluid remains approximately isosmotic to the bathing media. 7. No electrical potential difference could be recorded across the tubule wall.

Questions on the role of biofilms for the adaptation of microorganisms to unfavorable environmental factors by the example of P. aeruginosa

2020 ◽  
Vol 99 (4) ◽  
pp. 379-383
Author(s):  
Vasily N. Afonyushkin ◽  
N. A. Donchenko ◽  
Ju. N. Kozlova ◽  
N. A. Davidova ◽  
V. Yu. Koptev ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Environmental Factors ◽  
Barrier Function ◽  
Infectious Agent ◽  
Antagonistic Activity ◽  
The Body ◽  
Main Function ◽  
Pathogenic Potential ◽  
The Face

Pseudomonas aeruginosa is a widely represented species of bacteria possessing of a pathogenic potential. This infectious agent is causing wound infections, fibrotic cystitis, fibrosing pneumonia, bacterial sepsis, etc. The microorganism is highly resistant to antiseptics, disinfectants, immune system responses of the body. The responses of a quorum sense of this kind of bacteria ensure the inclusion of many pathogenicity factors. The analysis of the scientific literature made it possible to formulate four questions concerning the role of biofilms for the adaptation of P. aeruginosa to adverse environmental factors: Is another person appears to be predominantly of a source an etiological agent or the source of P. aeruginosa infection in the environment? Does the formation of biofilms influence on the antibiotic resistance? How the antagonistic activity of microorganisms is realized in biofilm form? What is the main function of biofilms in the functioning of bacteria? A hypothesis has been put forward the effect of biofilms on the increase of antibiotic resistance of bacteria and, in particular, P. aeruginosa to be secondary in charcter. It is more likely a biofilmboth to fulfill the function of storing nutrients and provide topical competition in the face of food scarcity. In connection with the incompatibility of the molecular radii of most antibiotics and pores in biofilm, biofilm is doubtful to be capable of performing a barrier function for protecting against antibiotics. However, with respect to antibodies and immunocompetent cells, the barrier function is beyond doubt. The biofilm is more likely to fulfill the function of storing nutrients and providing topical competition in conditions of scarcity of food resources.

Circadian tuning of motivation. A little organ of yesterday?

1995 ◽  
Vol 7 (2) ◽  
pp. 21-23 ◽  
Author(s):  
S. Daan
Keyword(s):  
Internal State ◽  
External Environment ◽  
Animal Behaviour ◽  
The Body ◽  
Biological Clocks ◽  
Motivational Systems ◽  
Regulatory Principle ◽  
The Face ◽  
Temporal Organisation ◽  
The Ideal

The analysis of motivational systems underlying temporal organisation in animal behaviour has relied primarily on two conceptual functional frameworks: Homeostasis and biological clocks. Homeostasis is one of the most general and influential concepts in physiology. Walter Cannon introduced homeostasis as a universal regulatory principle which animals employ to maintain constancy of their ‘internal milieu’ in the face of challenges and perturbations from the external environment. Cannon spoke of “The Wisdom of the Body”, the collective of responses designed to defend the ideal internal state against those perturbations.

scholarly journals Corrigendum: RNA-Seq Comparison of Larval and Adult Malpighian Tubules of the Yellow Fever Mosquito Aedes aegypti Reveals Life Stage-Specific Changes in Renal Function

2017 ◽  
Vol 8 ◽  
Author(s):  
Yiyi Li ◽  
Peter M. Piermarini ◽  
Carlos J. Esquivel ◽  
David P. Price ◽  
Hannah E. Drumm ◽  
...  
Keyword(s):  
Renal Function ◽  
Aedes Aegypti ◽  
Yellow Fever ◽  
Life Stage ◽  
Malpighian Tubules ◽  
Rna Seq ◽  
Yellow Fever Mosquito

Associated change in plantar temperature and sweating after transthoracic endoscopic T2–3 sympathectomy for palmar hyperhidrosis

2001 ◽  
Vol 95 (1) ◽  
pp. 58-63 ◽  
Author(s):  
Han-Jung Chen ◽  
Cheng-Loong Liang ◽  
Kang Lu
Keyword(s):  
Skin Temperature ◽  
Temperature Change ◽  
The Body ◽  
Palmar Hyperhidrosis ◽  
Compensatory Sweating ◽  
Content Type ◽  
Postoperative Changes ◽  
The Face ◽  
The Difference ◽  
Fine Print

Object. Transthoracic endoscopic T2–3 sympathectomy is currently the treatment of choice for palmar hyperhidrosis. Compensatory sweating of the face, trunk, thigh, and sole of the foot was found in more than 50% of patients who underwent this procedure. The authors conducted this study to investigate the associated intraoperative changes in plantar skin temperature and postoperative plantar sweating. Methods. One hundred patients with palmar hyperhidrosis underwent bilateral transthoracic endoscopic T2–3 sympathectomy. There were 60 female and 40 male patients who ranged in age from 13 to 40 years (mean age 21.6 years). Characteristics studied included changes in palmar and plantar skin temperature measured intraoperatively, as well as pre- and postoperative changes in plantar sweating and sympathetic skin responses (SSRs). In 59 patients (59%) elevation of plantar temperature was demonstrated at the end of the surgical procedure. In this group, plantar sweating was found to be exacerbated in three patients (5%); plantar sweating was improved in 52 patients (88.1%); and no change was demonstrated in four patients (6.8%). In the other group of patients in whom no temperature change occurred, increased plantar sweating was demonstrated in three patients (7.3%); plantar sweating was improved in 20 patients (48.8%); and no change was shown in 18 patients (43.9%). The difference between temperature and sweating change was significant (p = 0.001). Compared with the presympathectomy rate, the rate of absent SSR also significantly increased after sympathectomy: from 20 to 76% after electrical stimulation and 36 to 64% after deep inspiration stimulation, respectively (p < 0.05). Conclusions. In contrast to compensatory sweating in other parts of the body after T2–3 sympathetomy, improvement in plantar sweating was shown in 72% and worsened symptoms in 6% of patients. The intraoperative plantar skin temperature change and perioperative SSR demonstrated a correlation between these changes.

Multivariate Analysis in Genetic Studies

1972 ◽  
Vol 21 (3) ◽  
pp. 204-210 ◽  
Author(s):  
Ch. Susanne
Keyword(s):  
Multivariate Analysis ◽  
Environmental Factors ◽  
The Body ◽  
Biometrical Analysis ◽  
Genetic Studies ◽  
The Face ◽  
Generalized Distances ◽  
Sib Pairs

SummaryThe results are presented of a method of generalized distances calculated by a noncentral χ2 test and applied to compare 63 twin pairs and 196 sib pairs. The advantage of this method in biometrical analysis lies in the fact that several measurements can be utilised simultaneously. Besides, it takes into account the distance of each relative to the centre of the population and also has the advantage of permitting the comparison of distances between pairs of relatives whatever their age or sex.Generalized distances were calculated for four measurements of the head, five of the body and eleven of the face. For all three sets of measurements the influence of genetical factors was demonstrated. The body seems less influenced by environmental factors and more conditioned by genetic ones.

MINIMAL KNOTTING NUMBERS

2009 ◽  
Vol 18 (08) ◽  
pp. 1159-1173 ◽  
Author(s):  
CASEY MANN ◽  
JENNIFER MCLOUD-MANN ◽  
RAMONA RANALLI ◽  
NATHAN SMITH ◽  
BENJAMIN MCCARTY
Keyword(s):  
The Body ◽  
Computer Algorithm ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Lattice ◽  
The Face ◽  
Face Centered ◽  
Body Centered Cubic Lattice

This article concerns the minimal knotting number for several types of lattices, including the face-centered cubic lattice (fcc), two variations of the body-centered cubic lattice (bcc-14 and bcc-8), and simple-hexagonal lattices (sh). We find, through the use of a computer algorithm, that the minimal knotting number in sh is 20, in fcc is 15, in bcc-14 is 13, and bcc-8 is 18.

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