Peptide nature of two mosquito natriuretic factors

1986 ◽  
Vol 250 (3) ◽  
pp. R328-R332 ◽  
Author(s):  
D. H. Petzel ◽  
H. H. Hagedorn ◽  
K. W. Beyenbach
Keyword(s):  
Biological Activities ◽  
Biological Effects ◽  
Gel Filtration ◽  
Fluid Secretion ◽  
Malpighian Tubules ◽  
Peptide Bonds ◽  
Polar Low ◽  
Transepithelial Voltage ◽  
Fraction I

High-pressure liquid chromatography (HPLC) of saline extracts of Aedes aegypti heads yields three fractions (from a total of 108) that affect transepithelial voltage and/or fluid secretion in isolated Aedes Malpighian tubules. In this study we investigated the physical and chemical nature of the active materials in these fractions. Gel-filtration chromatography revealed that the molecular weights of the three fractions were between 1,900 and 2,700. To test their thermostability the fractions were repeatedly frozen and thawed over a period of 110 days without loss of biological activity. Boiling at 100 degrees C for 5 min failed to significantly reduce their biological effects in isolated Malpighian tubules. In contrast, treatment with the proteolytic enzyme mixture, pronase, destroyed activity in all three. Fraction I no longer depolarized the transepithelial voltage of in vitro perfused Malpighian tubules, and fractions II and III completely lost their ability to stimulate fluid secretion and to affect transepithelial voltage. We conclude that our HPLC isolation yields a heterogeneous group of three polar low-molecular weight peptides. Expression of their biological activities in Malpighian tubules depends on intact peptide bonds.

Preliminary isolation of mosquito natriuretic factor

1985 ◽  
Vol 249 (4) ◽  
pp. R379-R386 ◽  
Author(s):  
D. H. Petzel ◽  
H. H. Hagedorn ◽  
K. W. Beyenbach
Keyword(s):  
Fluid Secretion ◽  
Malpighian Tubules ◽  
Reverse Phase Hplc ◽  
Saline Extract ◽  
Natriuretic Factor ◽  
K Secretion ◽  
Transepithelial Voltage ◽  
Nacl Secretion ◽  
Fraction I

A natriuretic factor that triggers diuresis in isolated Malpighian tubules of the mosquito was isolated from the head of the yellow-fever mosquito Aedes aegypti by passing a saline extract of mosquito heads through low-pressure and then high-pressure liquid chromatography (HPLC) columns. Three fractions with biologic activity eluted during a reverse-phase HPLC linear acetonitrile gradient run. Fraction I depolarized the transepithelial voltage (Vt) of isolated perfused Malpighian tubules but did not not stimulate fluid secretion in the Ramsay assay (J. A. Ramsay, J. Exp. Biol. 31: 104–113, 1954). Fraction II depolarized and fraction III hyperpolarized Vt, and both stimulated fluid secretion three- to fourfold. Even though the effects of fractions II and III on Vt differed, both stimulated fluid secretion by increasing the rate of NaCl secretion without affecting K secretion. The selective stimulation of active secretory Na transport by fraction III is mimicked by cyclic AMP (cAMP), suggesting the second messenger role of cAMP in the effects of fraction III. Because fraction III stimulates a NaCl-rich, as opposed to KCl-rich, fluid, the term mosquito natriuretic factor is proposed for this active fraction.

Dibutyryl cAMP activates bumetanide-sensitive electrolyte transport in Malpighian tubules

1991 ◽  
Vol 261 (3) ◽  
pp. C521-C529 ◽  
Author(s):  
J. L. Hegarty ◽  
B. Zhang ◽  
T. L. Pannabecker ◽  
D. H. Petzel ◽  
M. D. Baustian ◽  
...  
Keyword(s):  
Yellow Fever ◽  
Apical Membrane ◽  
Basolateral Membrane ◽  
Fluid Secretion ◽  
Ringer Solution ◽  
Malpighian Tubules ◽  
Membrane Voltage ◽  
Dibutyryl Camp ◽  
K Secretion ◽  
Transepithelial Voltage

The effects of dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP) and bumetanide (both 10(-4) M) on transepithelial Na+, K+, Cl-, and fluid secretion and on tubule electrophysiology were studied in isolated Malpighian tubules of the yellow fever mosquito Aedes aegypti. Peritubular DBcAMP significantly increased Na+, Cl-, and fluid secretion but decreased K+ secretion. In DBcAMP-stimulated tubules, bumetanide caused Na+, Cl-, and fluid secretion to return to pre-cAMP control rates and K+ secretion to decrease further. Peritubular bumetanide significantly increased Na+ secretion and decreased K+ secretion so that Cl- and fluid secretion did not change. In bumetanide-treated tubules, the secretagogue effects of DBcAMP are blocked. In isolated Malpighian tubules perfused with symmetrical Ringer solution, DBcAMP significantly hyperpolarized the transepithelial voltage (VT) and depolarized the basolateral membrane voltage (Vbl) with no effect on apical membrane voltage (Va). Total transepithelial resistance (RT) and the fractional resistance of the basolateral membrane (fRbl) significantly decreased. Bumetanide also hyperpolarized VT and depolarized Vbl, however without significantly affecting RT and fRbl. Together these results suggest that, in addition to stimulating electroconductive transport, DBcAMP also activates a nonconductive bumetanide-sensitive transport system in Aedes Malpighian tubules.

scholarly journals Phytochemicals and cancer

2007 ◽  
Vol 66 (2) ◽  
pp. 207-215 ◽  
Author(s):  
Ian T. Johnson
Keyword(s):  
Fruits And Vegetables ◽  
Biological Activities ◽  
Human Subjects ◽  
Biological Effects ◽  
Plant Secondary Metabolites ◽  
Biologically Active ◽  
Carcinogenic Activity ◽  
Plant Foods ◽  
Carcinogenic Effects

Epidemiological studies showing a protective effect of diets rich in fruits and vegetables against cancer have focused attention on the possibility that biologically-active plant secondary metabolites exert anti-carcinogenic activity. This huge group of compounds, now collectively termed ‘phytochemicals’, provides much of the flavour and colour of edible plants and the beverages derived from them. Many of these compounds also exert anti-carcinogenic effects in animal models of cancer, and much progress has been made in defining their many biological activities at the molecular level. Such mechanisms include the detoxification and enhanced excretion of carcinogens, the suppression of inflammatory processes such as cyclooxygenase-2 expression, inhibition of mitosis and the induction of apoptosis at various stages in the progression and promotion of cancer. However, much of the research on phytochemicals has been conducted in vitro, with little regard to the bioavailability and metabolism of the compounds studied. Many phytochemicals present in plant foods are poorly absorbed by human subjects, and this fraction usually undergoes metabolism and rapid excretion. Some compounds that do exert anti-carcinogenic effects at realistic doses may contribute to the putative benefits of plant foods such as berries, brassica vegetables and tea, but further research with human subjects is required to fully confirm and quantify such benefits. Chemoprevention using pharmacological doses of isolated compounds, or the development of ‘customised’ vegetables, may prove valuable but such strategies require a full risk–benefit analysis based on a thorough understanding of the long-term biological effects of what are often surprisingly active compounds.

scholarly journals Evidences of Herbal Medicine-Derived Natural Products Effects in Inflammatory Lung Diseases

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Fernanda Paula R. Santana ◽  
Nathalia M. Pinheiro ◽  
Márcia Isabel B. Mernak ◽  
Renato F. Righetti ◽  
Mílton A. Martins ◽  
...  
Keyword(s):  
Natural Products ◽  
Herbal Medicine ◽  
Biological Activities ◽  
Biological Effects ◽  
Pulmonary Inflammation ◽  
Experimental Models ◽  
Chronic Obstructive ◽  
Anti Inflammatory

Pulmonary inflammation is a hallmark of many respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), and acute respiratory syndrome distress (ARDS). Most of these diseases are treated with anti-inflammatory therapy in order to prevent or to reduce the pulmonary inflammation. Herbal medicine-derived natural products have been used in folk medicine and scientific studies to evaluate the value of these compounds have grown in recent years. Many substances derived from plants have the biological effectsin vitroandin vivo, such as flavonoids, alkaloids, and terpenoids. Among the biological activities of natural products derived from plants can be pointed out the anti-inflammatory, antiviral, antiplatelet, antitumor anti-allergic activities, and antioxidant. Although many reports have evaluated the effects of these compounds in experimental models, studies evaluating clinical trials are scarce in the literature. This review aims to emphasize the effects of these different natural products in pulmonary diseases in experimental models and in humans and pointing out some possible mechanisms of action.

The molecular biology of mammalian arachidonic acid metabolism

1991 ◽  
Vol 260 (2) ◽  
pp. L13-L28 ◽  
Author(s):  
E. Sigal
Keyword(s):  
Arachidonic Acid ◽  
Acid Metabolism ◽  
Recombinant Dna ◽  
Biological Activities ◽  
Biological Effects ◽  
Arachidonic Acid Metabolism ◽  
Bioactive Metabolites ◽  
Wide Range

The metabolism of arachidonic acid by cyclooxygenase and lipoxygenase enzymes results in a wide range of oxidized products with potent biological activities. These metabolites, which include the prostaglandins and leukotrienes, have been implicated in the pathogenesis of a variety of inflammatory diseases. Research over the last decade has focused primarily on the elucidation of the chemical structure of the metabolites and their biological effects in vitro and in vivo. Recently, research on the enzymes that produce these bioactive metabolites through oxidization of arachidonic acid has intensified. Recombinant DNA techniques have enabled investigators to determine the nucleotide sequences for several of the enzymes in the arachidonic acid cascade. The resulting cDNAs are now being used to further investigate the biochemical and biological features of arachidonic acid metabolism. The purpose of this paper is to review how the cDNAs for these enzymes were obtained, what information they convey, and how they are being applied in current research.

scholarly journals Excretion in the House Cricket (Acheta Domesticus): Stimulation of Diuresis by Tissue Homogenates

1987 ◽  
Vol 129 (1) ◽  
pp. 63-81 ◽  
Author(s):  
JEFFREY H. SPRING ◽  
SHELIA R. HAZELTON
Keyword(s):  
Lethal Dose ◽  
Fluid Secretion ◽  
Sodium Concentration ◽  
Inhibitory Effect ◽  
Acheta Domesticus ◽  
Malpighian Tubules ◽  
Secretion Rate ◽  
Tissue Homogenates ◽  
Extreme Sensitivity

1. A new method is described for maintaining cricket Malpighian tubules in vitro. Warmed, oxygenated saline is circulated rapidly past the tubules, while the secreted urine is collected under oil for analysis. This technique allows the cricket tubules to be observed and manipulated for extended periods (6 h), in contrast to their short life (>1 h) using conventional methods. 2. Cricket tubules show extreme sensitivity to oxygen deprivation, such that 15 min of anoxia represents the median lethal dose (LD50) for in vitro preparations. 3. Homogenates of corpus cardiacum (CC) cause the rate of fluid secretion by the tubules to double. The maximum stimulation is dose-dependent over the range 0.01 to 1.0 CC. Homogenates of brain and other ganglia show much smaller stimulatory effects (0.01-0.02 CC-equivalents). Cyclic AMP mimics the increase in secretion rate, but has an inhibitory effect on the smooth muscle of the ureter. 4. Control preparations maintain a urine osmotic pressure (OP) that is hyperosmotic to the bath by 5–10 mosmol l−1. CC homogenate produces a decrease in urine OP to 10–12 mosmol l−1 hypo-osmotic to the bath. This suggests that active solute reabsorption is occurring in the lower tubule or ampulla. 5. Stimulation by CC homogenate increases the urine potassium concentration slightly less than two-fold, whereas the sodium concentration increases by a maximum of five-fold and remains at a higher concentration than potassium throughout the experiment. Tubule secretion rate is drastically inhibited in nominally sodium-free saline.

scholarly journals Insightful Valorization of the Biological Activities of Pani Heloch Leaves through Experimental and Computer-Aided Mechanisms

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5153
Author(s):  
Naureen Banu ◽  
Najmul Alam ◽  
Mohammad Nazmul Islam ◽  
Sanjida Islam ◽  
Shahenur Alam Sakib ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Methanol Extract ◽  
Biological Activities ◽  
Biological Effects ◽  
Experimental Models ◽  
Clot Lysis ◽  
Control Group ◽  
Anti Inflammatory

Pani heloch (Antidesma montanum) is traditionally used to treat innumerable diseases and is a source of wild vegetables for the management of different pathological conditions. The present study explored the qualitative phytochemicals; quantitative phenol and flavonoid contents; in vitro antioxidant, anti-inflammatory, and thrombolytic effects; and in vivo antipyretic and analgesic properties of the methanol extract of A. montanum leaves in different experimental models. The extract exhibited secondary metabolites including alkaloids, flavonoids, flavanols, phytosterols, cholesterols, phenols, terpenoids, glycosides, fixed oils, emodines, coumarins, resins, and tannins. Besides, Pani heloch showed strong antioxidant activity (IC50 = 99.00 µg/mL), while a moderate percentage of clot lysis (31.56%) in human blood and significant anti-inflammatory activity (p < 0.001) was achieved with the standard. Moreover, the analgesic and antipyretic properties appeared to trigger a significant response (p < 0.001) relative to in the control group. Besides, an in silico study of carpusin revealed favorable protein-binding affinities. Furthermore, the absorption, distribution, metabolism, excretion, and toxicity analysis and toxicological properties of all isolated compounds adopted Lipinski’s rule of five for drug-like potential and level of toxicity. Our research unveiled that the methanol extract of A. montanum leaves exhibited secondary metabolites that are a good source for managing inflammation, pyrexia, pain, and cellular toxicity. Computational approaches and further studies are required to identify the possible mechanism which responsible for the biological effects.

Design of new improved curcumin derivatives to multi-targets of cancer and inflammation

2020 ◽  
Vol 21 ◽  
Author(s):  
Veena V ◽  
Harikrishnan A ◽  
Sunali Khanna
Keyword(s):  
Biological Activities ◽  
Biological Effects ◽  
Curcuma Longa ◽  
In Vivo Studies ◽  
Critical Examination ◽  
Active Principle ◽  
Molecular Response ◽  
Curcumin Derivatives ◽  
Cancer And Inflammation

Background: Curcumin, a major active principle of Curcuma longa. There are more than 1700 citations in the Medline reflecting various biological effects of curcumin. Most of these biological activities are associated to the antioxidant, anti-inflammatory and antitumor activity of the molecule. Several reports suggest various targets of natural curcumin that includes growth factors, growth factor receptor, cytokines, enzymes and gene regulators of apoptosis. This review focuses on the improved curcumin derivatives that targets the cancer and inflammation. Methodology: In this present review, we explored the anticancer drugs with curcumin-based drugs under pre-clinical and clinical studies with critical examination. Based on the strong scientific reports of patentable and non-patented literature survey, we have investigated the mode of the interactions of curcumin-based molecules with the target molecules. Results: Advanced studies have added new dimensions of molecular response of cancer cells to curcumin at genomic level. However, poor bioavailability of the molecule seems to be the major limitation of the curcumin. Several researchers have involved to improve the curcumin derivatives to overcome this limitation. Sufficient data of clinical trials to various cancers that include multiple myeloma, pancreatic cancer and colon cancer are also discussed. Conclusion: The detailed analysis of structure activity relationship (SAR) and common synthesis of curcumin-based derivatives are discussed in review. Utilising the predictions of in silico coupled with validation reports of in vitro and in vivo studies have concluded many targets for curcumin. Among them, cancer related inflammation genes regulating curcumin-based molecules are very promising target to overcome hurdle in the multimodality therapy of cancer.

scholarly journals Excretion of NaCl and KCl loads in mosquitoes. 2. Effects of the small molecule Kir channel modulator VU573 and its inactive analog VU342

2014 ◽  
Vol 307 (7) ◽  
pp. R850-R861 ◽  
Author(s):  
Matthew F. Rouhier ◽  
Rebecca M. Hine ◽  
Seokhwan Terry Park ◽  
Rene Raphemot ◽  
Jerod Denton ◽  
...  
Keyword(s):  
Urinary Excretion ◽  
Small Molecules ◽  
Fluid Secretion ◽  
Ringer Solution ◽  
Malpighian Tubules ◽  
Kir Channel ◽  
Channel Modulator ◽  
Inactive Analog

The effect of two small molecules VU342 and VU573 on renal functions in the yellow fever mosquito Aedes aegypti was investigated in vitro and in vivo. In isolated Malpighian tubules, VU342 (10 μM) had no effect on the transepithelial secretion of Na+, K+, Cl−, and water. In contrast, 10 μM VU573 first stimulated and then inhibited the transepithelial secretion of fluid when the tubules were bathed in Na+-rich or K+-rich Ringer solution. The early stimulation was blocked by bumetanide, suggesting the transient stimulation of Na-K-2Cl cotransport, and the late inhibition of fluid secretion was consistent with the known block of AeKir1, an Aedes inward rectifier K+ channel, by VU573. VU342 and VU573 at a hemolymph concentration of about 11 μM had no effect on the diuresis triggered by hemolymph Na+ or K+ loads. VU342 at a hemolymph concentration of 420 μM had no effect on the diuresis elicited by hemolymph Na+ or K+ loads. In contrast, the same concentration of VU573 significantly diminished the Na+ diuresis by inhibiting the urinary excretion of Na+, Cl−, and water. In K+-loaded mosquitoes, 420 μM VU573 significantly diminished the K+ diuresis by inhibiting the urinary excretion of K+, Na+, Cl−, and water. We conclude that 1) the effects of VU573 observed in isolated Malpighian tubules are overwhelmed in vivo by the diuresis triggered with the coinjection of Na+ and K+ loads, and 2) at a hemolymph concentration of 420 μM VU573 affects Kir channels systemically, including those that might be involved in the release of diuretic hormones.

Isolation of FSH from bovine pituitary glands

1993 ◽  
Vol 137 (1) ◽  
pp. 59-68 ◽  
Author(s):  
J.-B. Wu ◽  
P. G. Stanton ◽  
D. M. Robertson ◽  
M. T. W. Hearn
Keyword(s):  
Amino Acid ◽  
Biological Activities ◽  
Gel Filtration ◽  
Exchange Chromatography ◽  
High Yield ◽  
Purification Procedure ◽  
In Vitro Bioassay ◽  
Α Subunit ◽  
Pituitary Glands

ABSTRACT An improved method is described for the isolation of FSH from bovine pituitary glands. The purification procedure consisted of an initial ammonium sulphate precipitation step followed by triazine-dye chromatography, immobilized metal affinity chromatography, high-performance anion-exchange chromatography and gel filtration. Three highly purified bovine FSH preparations (designated bFSH-A, -B and -C) were obtained, giving yields of approximately 5·7 mg FSH/kg bovine pituitary glands (wet weight), with specific radioreceptor activities for bFSH-A, -B and -C of 61, 25 and 29 units (NIH-FSH-S1)/mg protein respectively. The corresponding biological activities were 217 (bFSH-A), 62 (bFSH-B) and 86 (bFSH-C) units/mg, as measured by an FSH in-vitro bioassay. LH levels were found to be < 1% (w/w) as determined by an LH in-vitro bioassay. SDS-PAGE of these bFSH preparations under reducing conditions in 16% polyacrylamide gels showed two major silver-staining bands of apparent molecular masses 19·5 kDa and 15·8 kDa. Their amino acid compositions were in close agreement with the expected composition, based on the bFSH cDNA sequence and results reported by other investigators. N-terminal sequencing of the bFSH-A preparation yielded two major sequences consistent with α- and β-subunits, and a third minor (< 20%) sequence consistent with the α-subunit clipped at amino acid residue 6. It was concluded that the bFSH purification procedure reported here is a rapid method which produces bFSH in high yield and high purity, with radioreceptor and in-vitro specific activities comparable with those previously reported by other investigators. Journal of Endocrinology (1993) 137, 59–68

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