scholarly journals Uric Acid Is a Genuine Metabolite of Penicillium cyclopium and Stimulates the Expression of Alkaloid Biosynthesis in This Fungus

2002 ◽  
Vol 68 (4) ◽  
pp. 1524-1533 ◽  
Author(s):  
Florian Helbig ◽  
Jörg Steighardt ◽  
Werner Roos
Keyword(s):  
Uric Acid ◽  
Low Molecular Weight ◽  
Alkaloid Production ◽  
Alkaloid Biosynthesis ◽  
Penicillium Cyclopium ◽  
Measurable Activity ◽  
Reduced Rate ◽  
Rate Limiting

ABSTRACT On searching for endogenous, low-molecular-weight effectors of benzodiazepine alkaloid biosynthesis in Penicillium cyclopium uric acid was isolated from ethanolic or autoclaved mycelial extracts of this fungus. The isolation was based on a three-step high-pressure liquid chromatography procedure guided by a microplate bioassay, and uric acid was identified by mass spectrometry and the uricase reaction. Conidiospore suspensions that were treated with this compound during the early phase of outgrowth developed emerged cultures with an enhanced rate of alkaloid production. Uric acid treatment did not increase the in vitro measurable activity of the rate-limiting biosynthetic enzyme, cyclopeptine synthetase. However, these cultures displayed a reduced rate of uptake of the alkaloid precursor l-phenylalanine into the vacuoles of the hyphal cells as assayed in situ. It is suggested that the depressed capacity of vacuolar uptake caused by the contact of outgrowing spores with uric acid liberated from hyphal cells results in an enhanced availability of the precursor l-phenylalanine in the cytoplasm and thus accounts at least in part for the increase in alkaloid production.

Activities in vitro and in vivo of enzymes of benzodiazepine alkaloid biosynthesis during development of Penicillium cyclopium

1978 ◽  
Vol 17 (10) ◽  
pp. 1705-1709 ◽  
Author(s):  
Sabine Voigt ◽  
Salah El Kousy ◽  
Nicola Schwelle ◽  
Lutz Nover ◽  
Martin Luckner
Keyword(s):  
Alkaloid Biosynthesis ◽  
Penicillium Cyclopium

scholarly journals A 1H n.m.r. study of the kinetic properties expressed by glyceraldehyde phosphate dehydrogenase in the intact human erythrocyte

1982 ◽  
Vol 208 (3) ◽  
pp. 583-592 ◽  
Author(s):  
K M Brindle ◽  
I D Campbell ◽  
R J Simpson
Keyword(s):  
Human Erythrocyte ◽  
Intact Cell ◽  
Spin Echo ◽  
Glycolytic Flux ◽  
Kinetic Properties ◽  
Exchange Equilibrium ◽  
Glyceraldehyde Phosphate Dehydrogenase ◽  
Rate Limiting

Glyceraldehyde phosphate dehydrogenase is one of four glycolytic enzymes in the human erythrocyte that together can catalyse exchange of isotope between the C-2 position of lactate and solvent. Detailed measurements of the exchange can be made by using a non-invasive spin-echo p.m.r. method that has been described previously [Brindle, Brown, Campbell, Foxall & Simpson (1982) Biochem. J. 202, 589-602]. By studying the dependence of the exchange on the activity of an individual enzyme, the specific isotope-exchange equilibrium velocity of the enzyme can be measured. Suggestions that glyceraldehyde phosphate dehydrogenase is bound to the membrane in the intact cell, and that it may, under certain conditions, be rate-limiting for glycolytic flux, were examined in the present study by comparing the exchange properties expressed by the enzyme in situ and in vitro. It is concluded that glyceraldehyde phosphate dehydrogenase is not rate-limiting for glycolytic flux and that it is unlikely that a significant fraction of the enzyme is bound to the erythrocyte membrane in situ.

scholarly journals Arg-Vasotocin Directly Activates Isotocin Receptors and Induces COX2 Expression in Ovoviviparous Guppies

2021 ◽  
Vol 12 ◽  
Author(s):  
Li Kang Lyu ◽  
Jian Shuang Li ◽  
Xiao Jie Wang ◽  
Yi Jia Yao ◽  
Ji Fang Li ◽  
...  
Keyword(s):  
Poecilia Reticulata ◽  
Intraperitoneal Administration ◽  
Gene Expression Measurement ◽  
Reproductive Behaviors ◽  
Prostaglandin F ◽  
Rate Limiting ◽  
Cox2 Expression ◽  
Expression Measurement

Oxytocin (OT) is a crucial regulator of reproductive behaviors, including parturition in mammals. Arg-vasopressin (AVP) is a nonapeptide homologous to Arg-vasotocin (AVT) in teleosts that has comparable affinity for the OT receptor. In the present study, ovoviviparous guppies (Poecilia reticulata) were used to study the effect of AVT on delivery mediated by the activation of prostaglandin (PG) biosynthesis via isotocin (IT) receptors (ITRs). One copy each of it and avt and two copies of itrs were identified in guppies. The results of the affinity assay showed that various concentrations of AVT and IT (10−6, 10−7, and 10−8 mol/L) significantly activated itr1 (P < 0.05). In vitro experiments revealed significant upregulation (P < 0.05) of cyclooxygenase 2 (cox2), which is the rate-limiting enzyme involved in PG biosynthesis, and itr1 by AVT and IT. Furthermore, dual in situ hybridization detected positive signals for itr1 and cox2 at the same site, implying that ITR1 may regulate cox2 gene expression. Measurement of prostaglandin F2a (PGF2a) concentrations showed that AVT induced PGF2a synthesis (P < 0.05) and that the effect of IT was not significant. Finally, intraperitoneal administration of PGF2a significantly induced premature parturition of guppies. This study is the first to identify and characterize AVT and ITRs in guppies. The findings suggest that AVT promotes PG biosynthesis via ITR and that PGF2a induces delivery behavior in ovoviviparous guppies.

Release Characteristics In Vitro and In Vivo of In Situ Gels for a Novel Peptide Compared with Low-Molecular-Weight Hydrophilic Drug

2017 ◽  
Vol 14 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Guiying Zhang ◽  
Jie Hu ◽  
Qingbin Meng ◽  
Tao Wang ◽  
Xi Yang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Hydrophilic Drug

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

In Situ Localization of PPAR Gamma and Uncoupling Protein in Mouse Embryo Sections Using Digoxigenin-Labeled Riboprobes

1996 ◽  
Vol 54 ◽  
pp. 32-33
Author(s):  
C. Jennermann ◽  
S. A. Kliewer ◽  
D. C. Morris
Keyword(s):  
Alkaline Phosphatase ◽  
Room Temperature ◽  
Uncoupling Protein ◽  
Ppar Gamma ◽  
Nuclear Hormone Receptor ◽  
Full Length ◽  
Northern Analysis ◽  
Peroxisome Proliferator

Peroxisome proliferator-activated receptor gamma (PPARg) is a member of the nuclear hormone receptor superfamily and has been shown in vitro to regulate genes involved in lipid metabolism and adipocyte differentiation. By Northern analysis, we and other researchers have shown that expression of this receptor predominates in adipose tissue in adult mice, and appears first in whole-embryo mRNA at 13.5 days postconception. In situ hybridization was used to find out in which developing tissues PPARg is specifically expressed.Digoxigenin-labeled riboprobes were generated using the Genius™ 4 RNA Labeling Kit from Boehringer Mannheim. Full length PPAR gamma, obtained by PCR from mouse liver cDNA, was inserted into pBluescript SK and used as template for the transcription reaction. Probes of average size 200 base pairs were made by partial alkaline hydrolysis of the full length transcripts. The in situ hybridization assays were performed as described previously with some modifications. Frozen sections (10 μm thick) of day 18 mouse embryos were cut, fixed with 4% paraformaldehyde and acetylated with 0.25% acetic anhydride in 1.0M triethanolamine buffer. The sections were incubated for 2 hours at room temperature in pre-hybridization buffer, and were then hybridized with a probe concentration of 200μg per ml at 70° C, overnight in a humidified chamber. Following stringent washes in SSC buffers, the immunological detection steps were performed at room temperature. The alkaline phosphatase labeled, anti-digoxigenin antibody and detection buffers were purchased from Boehringer Mannheim. The sections were treated with a blocking buffer for one hour and incubated with antibody solution at a 1:5000 dilution for 2 hours, both at room temperature. Colored precipitate was formed by exposure to the alkaline phosphatase substrate nitrobluetetrazoliumchloride/ bromo-chloroindlylphosphate.

Effects of Unfractionated and Low Molecular Weight Heparins on Platelet Thromboxane Biosynthesis “In Vivo”

1994 ◽  
Vol 72 (06) ◽  
pp. 942-946 ◽  
Author(s):  
Raffaele Landolfi ◽  
Erica De Candia ◽  
Bianca Rocca ◽  
Giovanni Ciabattoni ◽  
Armando Antinori ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Low Molecular Weight Heparin ◽  
Primary Source ◽  
In Vivo Studies ◽  
Low Molecular Weight ◽  
Heparin Administration ◽  
To Receive

SummarySeveral “in vitro” and “in vivo” studies indicate that heparin administration may affect platelet function. In this study we investigated the effects of prophylactic heparin on thromboxane (Tx)A2 biosynthesis “in vivo”, as assessed by the urinary excretion of major enzymatic metabolites 11-dehydro-TxB2 and 2,3-dinor-TxB2. Twenty-four patients who were candidates for cholecystectomy because of uncomplicated lithiasis were randomly assigned to receive placebo, unfractionated heparin, low molecular weight heparin or unfractionaed heparin plus 100 mg aspirin. Measurements of daily excretion of Tx metabolites were performed before and during the treatment. In the groups assigned to placebo and to low molecular weight heparin there was no statistically significant modification of Tx metabolite excretion while patients receiving unfractionated heparin had a significant increase of both metabolites (11-dehydro-TxB2: 3844 ± 1388 vs 2092 ±777, p <0.05; 2,3-dinor-TxB2: 2737 ± 808 vs 1535 ± 771 pg/mg creatinine, p <0.05). In patients randomized to receive low-dose aspirin plus unfractionated heparin the excretion of the two metabolites was largely suppressed thus suggesting that platelets are the primary source of enhanced thromboxane biosynthesis associated with heparin administration. These data indicate that unfractionated heparin causes platelet activation “in vivo” and suggest that the use of low molecular weight heparin may avoid this complication.

The Effect of Dextran of Various Molecular Weight on the Coagulation in Dogs

1961 ◽  
Vol 06 (01) ◽  
pp. 015-024 ◽  
Author(s):  
Sven Erik Bergentz ◽  
Oddvar Eiken ◽  
Inga Marie Nilsson
Keyword(s):  
Molecular Weight ◽  
Body Weight ◽  
High Molecular Weight ◽  
Bleeding Time ◽  
Factor Vii ◽  
Low Molecular Weight ◽  
Factor V ◽  
Coagulation Mechanism ◽  
Coagulation Defects

Summary1. Infusions of low molecular weight dextran (Mw = 42 000) to dogs in doses of 1—1.5 g per kg body weight did not produce any significant changes in the coagulation mechanism.2. Infusions of high molecular weight dextran (Mw = 1 000 000) to dogs in doses of 1—1.5 g per kg body weight produced severe defects in the coagulation mechanism, namely prolongation of bleeding time and coagulation time, thrombocytopenia, pathological prothrombin consumption, decrease of fibrinogen, prothrombin and factor VII, factor V and AHG.3. Heparin treatment of the dogs was found to prevent the decrease of fibrinogen, prothrombin and factor VII, and factor V otherwise occurring after injection of high molecular weight dextran. Thrombocytopenia was not prevented.4. In in vitro experiments an interaction between fibrinogen and dextran of high and low molecular weight was found to take place in systems comprising pure fibrinogen. No such interaction occurred in the presence of plasma.5. It is concluded that the coagulation defects induced by infusions of high molecular weight dextran are due to intravascular coagulation.

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