Concentration of MgSO4 in the intestinal lumen of Opsanus beta limits osmoregulation in response to acute hypersalinity stress

2011 ◽  
Vol 300 (4) ◽  
pp. R895-R909 ◽  
Author(s):  
Janet Genz ◽  
M. Danielle McDonald ◽  
Martin Grosell
Keyword(s):  
Ionic Composition ◽  
Urine Osmolality ◽  
Intestinal Lumen ◽  
Natural Environments ◽  
Ambient Seawater ◽  
Opsanus Beta ◽  
Monovalent Ions ◽  
Ureteral Catheters ◽  
Tidal Pools

Marine teleosts constantly lose water to their surrounding environment, a problem exacerbated in fish exposed to salinity higher than normal seawater. Some fish undergo hypersaline exposures in their natural environments, such as short- and long-term increases in salinity occurring in small tidal pools and other isolated basins, lakes, or entire estuaries. Regardless of the degree of hypersalinity in the ambient water, intestinal absorption of monovalent ions drives water uptake to compensate for water loss, concentrating impermeable MgSO4 in the lumen. This study considers the potential of luminal [MgSO4] to limit intestinal water absorption, and therefore osmoregulation, in hypersalinity. The overall tolerance and physiological response of toadfish ( Opsanus beta) to hypersalinity exposure were examined. In vivo, fish in hypersaline waters containing artificially low [MgSO4] displayed significantly lower osmolality in both plasma and intestinal fluids, and increased survival at 85 parts per thousand, indicating improved osmoregulatory ability than in fish exposed to hypersalinity with ionic ratios similar to naturally occurring ratios. Intestinal sac preparations revealed that in addition to the osmotic pressure difference across the epithelium, the luminal ionic composition influenced the absorption of Na+, Cl−, and water. Hypersalinity exposure increased urine flow rates in fish fitted with ureteral catheters regardless of ionic composition of the ambient seawater, but it had no effect on urine osmolality or pH. Overall, concentrated MgSO4 within the intestinal lumen, rather than renal or branchial factors, is the primary limitation for osmoregulation by toadfish in hypersaline environments.

scholarly journals Nature Exposure and Its Effects on Immune System Functioning: A Systematic Review

2021 ◽  
Vol 18 (4) ◽  
pp. 1416
Author(s):  
Liisa Andersen ◽  
Sus Sola Corazon ◽  
Ulrika Karlsson Stigsdotter
Keyword(s):  
Systematic Review ◽  
Natural Killer Cell Activity ◽  
Public Health Practice ◽  
Killer Cell ◽  
Cell Activity ◽  
Natural Environments ◽  
Comprehensive Overview ◽  
Potential Health ◽  
Positive Effects

Given the drastic changes in our lifestyles and ecosystems worldwide, the potential health effects of natural environments have grown into a highly pervasive topic. Recent scientific findings suggest beneficial effects from nature exposure on human immune responses. This review aims at providing a comprehensive overview of literature published on immunomodulatory effects of nature exposure by inhalation of natural substances. A systematic database search was performed in SCOPUS and PubMed. The quality and potential bias of included studies (n = 33) were assessed by applying the EPHPP (Effective Public Health Practice Project) tool for human studies and the ARRIVE (Animal Research: Reporting of In Vivo Experiments) and SYRCLE (Systematic Review Centre for Laboratory Animal Experimentation) tools for animal studies. The synthesis of reviewed studies points to positive effects of nature exposure on immunological health parameters; such as anti-inflammatory, anti-allergic, anti-asthmatic effects or increased NK (natural killer) cell activity. Decreased expression of pro-inflammatory molecules, infiltration of leukocytes and release of cytotoxic mediators are outcomes that may serve as a baseline for further studies. However, partially weak study designs evoked uncertainties about outcome reproducibility and key questions remain open concerning effect sizes, duration of exposure and contributions of specific vegetation or ecosystem types.

scholarly journals In vivo transcriptome analysis provides insights into host-dependent expression of virulence factors by Yersinia entomophaga MH96, during infection of Galleria mellonella

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Amber R Paulson ◽  
Maureen O’Callaghan ◽  
Xue-Xian Zhang ◽  
Paul B Rainey ◽  
Mark R H Hurst
Keyword(s):  
Galleria Mellonella ◽  
Functional Enrichment ◽  
Natural Environments ◽  
Insecticidal Toxin ◽  
Heat Stable ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Cell Densities

Abstract The function of microbes can be inferred from knowledge of genes specifically expressed in natural environments. Here, we report the in vivo transcriptome of the entomopathogenic bacterium Yersinia entomophaga MH96, captured during initial, septicemic, and pre-cadaveric stages of intrahemocoelic infection in Galleria mellonella. A total of 1285 genes were significantly upregulated by MH96 during infection; 829 genes responded to in vivo conditions during at least one stage of infection, 289 responded during two stages of infection, and 167 transcripts responded throughout all three stages of infection compared to in vitro conditions at equivalent cell densities. Genes upregulated during the earliest infection stage included components of the insecticidal toxin complex Yen-TC (chi1, chi2, and yenC1), genes for rearrangement hotspot element containing protein yenC3, cytolethal distending toxin cdtAB, and vegetative insecticidal toxin vip2. Genes more highly expressed throughout the infection cycle included the putative heat-stable enterotoxin yenT and three adhesins (usher-chaperone fimbria, filamentous hemagglutinin, and an AidA-like secreted adhesin). Clustering and functional enrichment of gene expression data also revealed expression of genes encoding type III and VI secretion system-associated effectors. Together these data provide insight into the pathobiology of MH96 and serve as an important resource supporting efforts to identify novel insecticidal agents.

Interactions between ADH and prostaglandins in isolated erythrocyte-perfused rat kidney

1987 ◽  
Vol 252 (2) ◽  
pp. F331-F337 ◽  
Author(s):  
W. Lieberthal ◽  
M. L. Vasilevsky ◽  
C. R. Valeri ◽  
N. G. Levinsky
Keyword(s):  
Sodium Excretion ◽  
Rat Kidney ◽  
Urine Osmolality ◽  
Sodium Reabsorption ◽  
Urinary Osmolality ◽  
Hemodynamic Characteristics ◽  
Urinary Concentrating Ability ◽  
Tubular Morphology ◽  
Isolated Kidneys

Interactions between antidiuretic hormone (ADH) and renal prostaglandins in the regulation of sodium reabsorption and urinary concentrating ability were studied in isolated erythrocyte-perfused rat kidneys (IEPK). In this model, hemodynamic characteristics are comparable to those found in vivo, and tubular morphology is preserved throughout the period of perfusion. [Deamino]-D-arginine vasopressin (dDAVP) markedly reduced fractional sodium excretion (FE Na) in the IEPK from 3.5 +/- 0.6 to 0.45 +/- 0.14%. After indomethacin, FE Na fell still further to 0.08 +/- 0.02%. In the absence of dDAVP indomethacin had no effect on sodium excretion; FE Na was 2.4 +/- 0.6% in control and 2.0 +/- 0.4% in indomethacin-treated groups. dDAVP increased urine osmolality in the IEPK to 741 +/- 26 mosmol/kg. When prostaglandin synthesis was blocked with indomethacin, urinary osmolality increased further to 1,180 +/- 94 mosmol/kg. In isolated kidneys perfused without erythrocytes (IPK), dDAVP decreased FENa from 14.5 +/- 1.8% to 9.6 +/- 1.2%; addition of indomethacin had no further effect. dDAVP increased urine osmolality only modestly to 350 +/- 12 mosmol/kg in the IPK and indomethacin did not increase concentrating ability further (342 +/- 7 mosmol/kg). Thus the IEPK (unlike the IPK) can excrete a markedly hypertonic urine in response to ADH. ADH also enhances tubular reabsorption of sodium in the IEPK. Prostaglandins inhibit both these actions of ADH but do not directly affect sodium excretion in the absence of the hormone.

Responses to Hypersaline Exposure in the Euryhaline Crayfish PAcifastacus Leniusculus: II. Modulation of Haemocyanin Oxygen Binding In Vitro and In Vivo

1982 ◽  
Vol 99 (1) ◽  
pp. 447-467
Author(s):  
MICHÈLE G. WHEATLY ◽  
B. R. MCMAHON
Keyword(s):  
Salt Effect ◽  
Ionic Composition ◽  
Inorganic Ions ◽  
Pacifastacus Leniusculus ◽  
Oxygen Binding ◽  
Complete Saturation ◽  
O2 Delivery ◽  
O2 Binding

The effect of 48 h of hypersaline exposure (25, 50 and 75% SW) on haemocyanin oxygenation properties in the euryhaline crayfish Pacifastacus leniusculus was investigated in vitro and in vivo. In vitro significant increases in affinity and cooperativity were measured, although the magnitude of the Bohr shift was unaffected. In vitro dialysis of haemolymph against physiological salines of variable ionic composition proved that these changes were only partly attributable to altered levels of haemolymph ions, implicating the existence of modulators other than H+ and inorganic ions, the possible identities of which are discussed. Significant depressions of both pre- and postbranchial oxygen tensions (Pv, Ov, O2 and Pa, Oa, O2) were observed, but O2 delivery was maintained by utilization of the venous reserve and by an increase in haemocyanin O2 affinity. This occurred despite a concomitant acidosis whose effect on O2 affinity was directly opposed by the ‘salt’ effect. Under hypersaline conditions, haemocyanin played an increasingly important role in O2 delivery in vivo. Despite a reduction in the concentration of combined O2 at complete saturation of the pigment (CmaxHCyOHCyO2). indicating lowered haemocyanin concentration, compensatory changes in O2-binding and cardiac output precluded an impairment to O2 transfer. Equilibration at the tissues (Et,Ot,O2) in FW was less effective than at the gills (Eb,Ob,O2 but progressively improved with hypersaline exposure reversing this trend. Although effects of increased salinity on O2 equilibrium characteristics were qualitatively similar in vivo and in vitro, some interesting quantitative differences are discussed.

Magnesium and calcium as regulators of intestinal permeability

1964 ◽  
Vol 206 (1) ◽  
pp. 243-246 ◽  
Author(s):  
C. S. Tidball
Keyword(s):  
Intestinal Permeability ◽  
Calcium Salt ◽  
Ionic Composition ◽  
Intestinal Lumen ◽  
Phenol Red ◽  
Sodium Pentobarbital ◽  
All Solutions ◽  
Physiologic Saline ◽  
The Mean ◽  
And Control

The absorption of phenolsulfonphthalein (phenol red) was used as a measure of intestinal permeability in rats anesthetized with sodium pentobarbital. All solutions placed in the intestinal lumen were adjusted to pH 7.0 and 300 mosmoles/liter. When 5 ml of a 1 mm solution of phenol red were placed in either proximal or distal halves of the small intestine the mean hourly absorption was 1.1%. The presence of 25 mm/liter ethylenediaminetetraacetate (EDTA) as the calcium salt did not alter phenol red absorption. With 25 mm/liter NaEDTA in the lumen, the absorption of phenol red was increased tenfold. After NaEDTA had been present for 1 hr, rinsing the lumen produced results which varied with the ionic composition of the rinsing solution. Balanced physiologic saline did not reverse the increased permeability. A CaCl2 rinse produced a permeability intermediate between NaEDTA and control levels. A MgCI2 rinse reinstated normal permeability. It is concluded that magnesium and calcium, loosely bound in the structure of the membrane, regulate the aqueous permeability of the intestinal epithelium.

scholarly journals Intestinal Permeability Assays: a Review

2021 ◽  
Vol 31 (1) ◽  
pp. 20-30
Author(s):  
A. A. Iakupova ◽  
S. R. Abdulkhakov ◽  
R. K. Zalyalov ◽  
A. G. Safin ◽  
R. A. Abdulkhakov
Keyword(s):  
Intestinal Permeability ◽  
Ex Vivo ◽  
Venous Blood ◽  
Intestinal Barrier ◽  
Intestinal Lumen ◽  
Alcoholic Fatty Liver ◽  
Key Points ◽  
Assessment Techniques ◽  
Portal Venous Blood

Aim. A literature review of intestinal permeability assessment techniques.Key points. The intestinal barrier is a functional entity separating the intestinal lumen and internal body, and intestinal permeability is a measure of the barrier functionality. The intestinal barrier integrity and permeability assays differ by the application setting (in vivo or ex vivo), subject (human or animal), marker molecules used to assess permeability (ions, various size carbohydrates, macromolecules, antigens, bacterial products and bacteria), biomaterial for the marker concentration assays (peripheral blood, portal venous blood, urine, stool). Despite a great variety of methods for assessing intestinal permeability, their clinical application requires further studies due to a lack of standardisation, the complexity of selected techniques and occasional limited reliability of results.Conclusion. Further investigation and improvement of intestinal permeability assays is required. The assay and result standardisation will facilitate practice in functional and organic intestinal diseases, as well as allergies, diabetes mellitus, non-alcoholic fatty liver disease and some other illnesses.

Amino acid modulation of in vivo intestinal zinc absorption in freshwater rainbow trout

2002 ◽  
Vol 205 (1) ◽  
pp. 151-158 ◽  
Author(s):  
Chris N. Glover ◽  
Christer Hogstrand
Keyword(s):  
Amino Acids ◽  
Rainbow Trout ◽  
Amino Acid ◽  
Zinc Ion ◽  
Zinc Uptake ◽  
Intestinal Lumen ◽  
Zinc Absorption ◽  
Zinc Accumulation ◽  
Rainbow Trout Oncorhynchus Mykiss

SUMMARY The composition of the intestinal lumen is likely to have considerable influence upon the absorption, and consequently the nutrition and/or toxicity, of ingested zinc in aquatic environments, where zinc is both a nutrient and a toxicant of importance. The effects of amino acids upon intestinal zinc uptake in freshwater rainbow trout (Oncorhynchus mykiss) were studied using an in vivo perfusion technique. The presence of histidine, cysteine and taurine had distinct modifying actions upon quantitative and qualitative zinc absorption, compared to perfusion of zinc alone. Alterations in zinc transport were not correlated with changes in levels of free zinc ion. The chemical nature of the zinc–amino acid chelate, rather than the chelation itself, appeared to have the most important influence upon zinc absorption. l-histidine, despite a strong zinc-chelating effect, maintained quantitative zinc uptake at control (zinc alone) levels. This effect correlated with the formation of Zn(His)2 species. d-histidine at a luminal concentration of 100 mmol l–1 significantly enhanced subepithelial zinc accumulation, but reduced the fraction of zinc that was retained and absorbed by the fish. The possibility of a Zn(His)2-mediated pathway for intestinal uptake is discussed. l-cysteine specifically stimulated the accumulation of zinc post-intestinally, an effect attributed to enhanced zinc accumulation in the blood. Taurine increased subepithelial zinc accumulation, but decreased the passage of zinc to post-intestinal compartments. Amino acids are proposed to have important roles in modifying intestinal zinc uptake with potential implications for environmental toxicity as well as aquaculture.

Role of endothelin receptor subtypes in the in vivo regulation of renal function

1995 ◽  
Vol 268 (3) ◽  
pp. F455-F460 ◽  
Author(s):  
A. L. Clavell ◽  
A. J. Stingo ◽  
K. B. Margulies ◽  
R. R. Brandt ◽  
J. C. Burnett
Keyword(s):  
Sodium Excretion ◽  
Urine Osmolality ◽  
Receptor Activation ◽  
Receptor Subtypes ◽  
Low Doses ◽  
Renal Vasoconstriction ◽  
Etb Receptor ◽  
Diuretic Response

Endothelin (ET) is a potent vasoconstrictor peptide of endothelial origin, which at low doses results in renal vasoconstriction and diuresis with variable actions on sodium excretion. The current study conducted in four groups of anesthetized dogs was designed to define the role of the ETA and ETB receptor subtypes in the renal actions of low-dose exogenous ET. Group 1 (n = 4) animals served as time controls. In group 2 (n = 6) a systemic ET-1 (5 ng.kg-1.min-1) infusion mediated renal vasoconstriction, antinatriuresis with increases in proximal fractional reabsorption of sodium, and diuresis with a decrease in urine osmolality. In group 3 (n = 6) intrarenal BQ-123 (4 micrograms.kg-1.min-1), a selective ETA antagonist, abolished the systemic ET-1-mediated changes in renal hemodynamics and unmasked a natriuretic action at the level of the proximal tubule. In contrast, the diuretic response of ET was not altered by BQ-123. In group 4 (n = 6) intrarenal sarafotoxin 6-c, a selective ETB receptor agonist, resulted in a diuretic response without a change in sodium excretion. These studies suggest that the ETA receptor contributes to the renal vasoconstriction, whereas the ETB receptor is largely responsible for the diuretic response during exogenous ET. This study also suggests that at low doses ET is natriuretic in vivo by decreasing proximal tubular reabsorption of sodium independent of ETA or ETB receptor activation.

scholarly journals Heavily Armed Ancestors: CRISPR Immunity and Applications in Archaea with a Comparative Analysis of CRISPR Types in Sulfolobales

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1523
Author(s):  
Isabelle Anna Zink ◽  
Erika Wimmer ◽  
Christa Schleper
Keyword(s):  
Comparative Analysis ◽  
Molecular Mechanisms ◽  
Model Organisms ◽  
Special Focus ◽  
Natural Environments ◽  
Type I ◽  
Accessory Proteins ◽  
Type Iii

Prokaryotes are constantly coping with attacks by viruses in their natural environments and therefore have evolved an impressive array of defense systems. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is an adaptive immune system found in the majority of archaea and about half of bacteria which stores pieces of infecting viral DNA as spacers in genomic CRISPR arrays to reuse them for specific virus destruction upon a second wave of infection. In detail, small CRISPR RNAs (crRNAs) are transcribed from CRISPR arrays and incorporated into type-specific CRISPR effector complexes which further degrade foreign nucleic acids complementary to the crRNA. This review gives an overview of CRISPR immunity to newcomers in the field and an update on CRISPR literature in archaea by comparing the functional mechanisms and abundances of the diverse CRISPR types. A bigger fraction is dedicated to the versatile and prevalent CRISPR type III systems, as tremendous progress has been made recently using archaeal models in discerning the controlled molecular mechanisms of their unique tripartite mode of action including RNA interference, DNA interference and the unique cyclic-oligoadenylate signaling that induces promiscuous RNA shredding by CARF-domain ribonucleases. The second half of the review spotlights CRISPR in archaea outlining seminal in vivo and in vitro studies in model organisms of the euryarchaeal and crenarchaeal phyla, including the application of CRISPR-Cas for genome editing and gene silencing. In the last section, a special focus is laid on members of the crenarchaeal hyperthermophilic order Sulfolobales by presenting a thorough comparative analysis about the distribution and abundance of CRISPR-Cas systems, including arrays and spacers as well as CRISPR-accessory proteins in all 53 genomes available to date. Interestingly, we find that CRISPR type III and the DNA-degrading CRISPR type I complexes co-exist in more than two thirds of these genomes. Furthermore, we identified ring nuclease candidates in all but two genomes and found that they generally co-exist with the above-mentioned CARF domain ribonucleases Csx1/Csm6. These observations, together with published literature allowed us to draft a working model of how CRISPR-Cas systems and accessory proteins cross talk to establish native CRISPR anti-virus immunity in a Sulfolobales cell.

Dissociation between plasma, urine, and renal papillary cyclic AMP content following vasopressin and DDAVP

1979 ◽  
Vol 237 (3) ◽  
pp. F218-F225 ◽  
Author(s):  
M. J. Bia ◽  
S. Dewitt ◽  
J. N. Forrest
Keyword(s):  
Cyclic Amp ◽  
Urine Osmolality ◽  
Brattleboro Rats ◽  
Renal Papilla ◽  
Brattleboro Rat ◽  
Clearance Studies ◽  
Urinary Cyclic Amp ◽  
Stimulation Of

The effects of in vivo physiologic doses of vasopressin and 1-deamino-8-D-arginine vasopressin (DDAVP) on the cyclic AMP content of plasma, urine, and renal papillary tissue were determined in the ADH-deficient Brattleboro rat. During clearance studies, plasma cyclic AMP concentrations and both total and nephrogenous urinary cyclic AMP excretion in vasopressin- and DDAVP-treated rats were similar to the values in time-matched controls. In contrast, in situ renal papillary cyclic AMP content was higher (P less than 0.001) in both vasopressin- (35.7 +/- 3.6 pmol/mg protein) and DDAVP- (29.7 +/- 2.2 pmol/mg protein) treated rats compared to controls (15.1 +/- 1.3 pmol/mg protein). Endogenous stimulation of vasopressin by dehydration in normal rats increased both papillary cyclic AMP content (27.1 +/- 2.7 pmol/mg protein) and urine osmolality, whereas no change in papillary cyclic AMP was observed following dehydration in Brattleboro rats (13.6 +/- 0.8 pmol/mg protein) despite an increase in urine osmolality. The results demonstrate that changes in cyclic AMP following in vivo vasopressin are best demonstrated by measurement of in situ cyclic AMP content of the renal papilla, whereas total urinary cyclic AMP and nephrogenous cyclic AMP are not useful indices of tubular sensitivity to this hormone.

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