Studies on a carbonic anhydrase from the midgut epithelium of larvae of lepidoptera

Turbeck, Børge Ove; Foder, Birthe

doi:10.1016/0005-2744(70)90187-7

Cited by 20 publications

(4 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, with our microsatellite markers panel, we detected one outlier locus that could be mapped at a unique location in the reference genome and was in the vicinity of a putative gene coding for a carbonic anhydrase enzyme. These enzymes seem to be involved in pH regulation (alkalization mechanisms) of a lepidopteran caterpillar and larval mosquito guts [64]–[66]. Thus, we suggest that this gene is a promising candidate for future functional analysis.…”

Section: Discussionmentioning

confidence: 87%

Nuclear Genetic Diversity in Human Lice (Pediculus humanus) Reveals Continental Differences and High Inbreeding among Worldwide Populations

et al. 2013

View full text Add to dashboard Cite

Understanding the evolution of parasites is important to both basic and applied evolutionary biology. Knowledge of the genetic structure of parasite populations is critical for our ability to predict how an infection can spread through a host population and for the design of effective control methods. However, very little is known about the genetic structure of most human parasites, including the human louse (Pediculus humanus). This species is composed of two ecotypes: the head louse (Pediculus humanus capitis De Geer), and the clothing (body) louse (Pediculus humanus humanus Linnaeus). Hundreds of millions of head louse infestations affect children every year, and this number is on the rise, in part because of increased resistance to insecticides. Clothing lice affect mostly homeless and refugee-camp populations and although they are less prevalent than head lice, the medical consequences are more severe because they vector deadly bacterial pathogens. In this study we present the first assessment of the genetic structure of human louse populations by analyzing the nuclear genetic variation at 15 newly developed microsatellite loci in 93 human lice from 11 sites in four world regions. Both ecotypes showed heterozygote deficits relative to Hardy–Weinberg equilibrium and high inbreeding values, an expected pattern given their parasitic life history. Bayesian clustering analyses assigned lice to four distinct genetic clusters that were geographically structured. The low levels of gene flow among louse populations suggested that the evolution of insecticide resistance in lice would most likely be affected by local selection pressures, underscoring the importance of tailoring control strategies to population-specific genetic makeup and evolutionary history. Our panel of microsatellite markers provides powerful data to investigate not only ecological and evolutionary processes in lice, but also those in their human hosts because of the long-term coevolutionary association between lice and humans.

show abstract

Section: Discussionmentioning

confidence: 87%

Nuclear Genetic Diversity in Human Lice (Pediculus humanus) Reveals Continental Differences and High Inbreeding among Worldwide Populations

et al. 2013

View full text Add to dashboard Cite

show abstract

“…Studies with other vertebrate tissues have given the impression that carbonic anhydrase is essentially a soluble cell constituent (Datta & Shepard, 1959;Karler & Woodbury, 1960;Shepard, 1962;Mitchell, Mitchell & Hanahan, 1965;Bernstein et al 1968), though a membraneassociated role in ion-transporting epithelia has been proposed on the basis of physiological (Rector, Carter & Seldin, 1965) and histochemical 88 DISTRIBUTION OF CARBONIC ANHYDRASES (Hansson, 1968) observations. A carbonic anhydrase in the mid-gut epithelium of lepidoptera larvae is entirely associated with particulate cell material when the tissue is homogenized under conditions similar to those used here (Turbeck & Foder, 1970). Using a conventional homogenizing medium, 45 % of the 'high activity' carbonic anhydrase of the proximal colonic mucosa was located in particulate matter, and reasons have been given for believing that this may be the more usual situation in regard to the carbonic anhydrase activity of mammalian tissues.…”

Section: Tissue Distribution Of Carbonic Anhydrase Isoenzymesmentioning

confidence: 93%

“…A carbonic anhydrase in the mid-gut epithelium of lepidoptera larvae is entirely associated with particulate cell material when the tissue is homogenized under conditions similar to those used here (Turbeck & Foder, 1970). Using a conventional homogenizing medium, 45 % of the 'high activity' carbonic anhydrase of the proximal colonic mucosa was located in particulate matter, and reasons have been given for believing that this may be the more usual situation in regard to the carbonic anhydrase activity of mammalian tissues.…”

Section: The Subcellular Distribution Of Carbonic Anhydrase Activitymentioning

confidence: 96%

The isoenzymes of carbonic anhydrase: tissue, subcellular distribution and functional significance, with particular reference to the intestinal tract

Carter¹,

Parsons²

1971

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. The total carbonic anhydrase activity in some guinea-pig tissues has been measured using a pH-stat procedure. Stomach, gall bladder, proximal colon and caecum all possess more carbonic anhydrase activity per unit amount of protein than does whole blood.2. The carbonic anhydrase activity of the small intestine is low. Reasons are given for supposing that activity found there is not entirely due to contamination by whole blood, and it is suggested that in this tissue the enzyme may be localized in some cell type other than the columnar absorbing cells.3. Evidence is presented which indicates that heavy metals interfere with the activity of the enzyme as measured in tissue homogenates.4. The distribution and concentration of the two major isoenzymes of carbonic anhydrase have been measured in different tissues. Blood and proximal colon contain both isoenzymes in comparable concentrations, the ratio of the concentration of the 'low activity' isoenzyme to that of the 'high activity' being about 2. The gastric mucosa contains much 'high activity' carbonic anhydrase, but only a negligible amount of the 'low activity' isoenzyme. In the caecal mucosa, the 'low activity' isoenzyme is predominant, the ratio of its concentration to that of the 'high activity' isoenzyme being about 9. It is also found that more than 15 % of the protein in the caecal mucosa is accounted for as carbonic anhydrase enzymes.5. It is found that some 45 % of the total carbonic anhydrase activity of sucrose homogenates of the guinea-pig colon is bound to particles. The activity is located mainly in the nuclear and microvillous fraction and in the 'high-speed supernatant' fraction. The form of enzyme bound is M. J. CARTER AND D. S. PARSONS largely of the 'high activity' variety. When the tissue is homogenized in potassium chloride solutions less than 4 % of the total activity is recovered in particulate fractions. The amount of activity which is bound to particulate fractions increases as the ionic strength or pH of the homogenate is lowered.6. The findings are discussed in relation to the possible physiological roles of the isoenzymes in tissues other than blood. Possible relationships between the presence of the enzymes and the metabolism and transport of ammonium and fatty acids are considered.

show abstract

“…The carbonic anhydrase of the midgut of these creatures is distinguished by the fact that it is entirely particle-bound according to centrifugation studies using homogenized preparations. Moreover, this enzyme is apparently activated by chloride ions, whereas mammalian carbonic anhydrases are inhibited (Turbeck & Foder, 1970). The inner ear of the cat is particularly interesting.…”

Section: Carbonic Anhydrase and Ion-transporting Epitheliamentioning

confidence: 99%

Carbonic Anhydrase:isoenzymes. Properties. Distribution. And Functional Significance

Carter¹

1972

Biological Reviews

226

View full text Add to dashboard Cite

Summary 1. Carbonic anhydrases from vertebrates, plants and bacteria have molecular weights of 30,000 (or multiples thereof), contain one zinc atom per 30,000 molecular weight, and are inhibited by acetazolamide and related compounds. 2. In mammals, there are two major isoenzymes of carbonic anhydrase. The so‐called ‘high activity’ carbonic anhydrase possesses a carbon dioxide‐hydratase activity many times (in the case of the guinea‐pig isoenzymes, 18 times) that of the ‘low activity’ isoenzyme. 3. The mammalian isoenzymes differ from one another in their amino‐acid compositions (the difference in serine contents being a consistent finding in a number of species), in their physical properties (isoelectric pH, retention by ion‐exchange resins, electrophoretic mobility) and in their kinetic properties. 4. Mammalian carbonic anhydrases also catalyse the hydrolysis of some esters and the hydration of aldehydes. Their relative activities with these other substrates may be substantially different from their relative activities with carbon dioxide as substrate. The discovery that carbonic anhydrase may also catalyse other reactions raises the possibility that the enzyme may have other roles in metabolic pathways (e.g., in certain dehydrogenation reactions). 5. In plants, the role of carbonic anhydrase may be to catalyse the inter‐conversion of bicarbonate and carbon dioxide, to provide ‘carbon dioxide’ in the form appropriate for carbon‐fixing reactions. A similar role has been suggested for the carbonic anhydrase found in Neissariae. 6. The carbonic anhydrase of vertebrates (the ‘high activity’ isoenzyme of mammals) is found in many ion‐transporting epithelia, but its role in them is still uncertain. It occurs in acid‐transporting epithelia such as the stomach and kidney, and also in certain bicarbonate‐transporting epithelia like the large intestine. There is, however, a poor correlation between the presence of the enzyme and the occurrence of acid or bicarbonate secretion. Thus there is little or no carbonic anhydrase in some tissues noted for their ability to secrete bicarbonate ions, such as the pancreas and ileum. Conversely, carbonic anhydrase‐containing tissues like the avian salt gland and the elasmobranch rectal gland form concentrated sodium chloride solutions which are of nearly neutral pH. The correlation between the distribution of carbonic anhydrase and the occurrence of active chloride transport appears similar to that between carbonic anhydrase and bicarbonate ion transport. 7. While the red cells of most mammalian species so far studied contain both ‘high activity’ and ‘low activity’ isoenzymes, the latter is reported to be absent from the erythrocytes of sheep, ox and dog. Presumably the ‘low activity’ isoenzyme is not necessary for an adequate rate of carbon dioxide exchange to occur between tissues and lungs in these species. 8. The ‘low activity’ isoenzyme is present in tissues other than blood, for example, the colon, caecum and ox rumen, and probably also, the gall bladder and kidney medulla. Its...

show abstract

Studies on a carbonic anhydrase from the midgut epithelium of larvae of lepidoptera

Cited by 20 publications

References 20 publications

Nuclear Genetic Diversity in Human Lice (Pediculus humanus) Reveals Continental Differences and High Inbreeding among Worldwide Populations

Nuclear Genetic Diversity in Human Lice (Pediculus humanus) Reveals Continental Differences and High Inbreeding among Worldwide Populations

The isoenzymes of carbonic anhydrase: tissue, subcellular distribution and functional significance, with particular reference to the intestinal tract

Carbonic Anhydrase:isoenzymes. Properties. Distribution. And Functional Significance

Contact Info

Product

Resources

About