Amino acid sequence of the alpha subunit and computer modelling of the alpha and beta subunits of echicetin from the venom of Echis carinatus (saw-scaled viper)

Echicetin, a heterodimeric protein from the venom of Echis carinatus, binds to platelet glycoprotein Ib (GPIb) and so inhibits platelet aggregation or agglutination induced by various platelet agonists acting via GPIb. The amino acid sequence of the beta subunit of echicetin has been reported and found to belong to the recently identified snake venom subclass of the C-type lectin protein family. Echicetin alpha and beta subunits were purified. N-terminal sequence analysis provided direct evidence that the protein purified was echicetin. The paper presents the complete amino acid sequence of the alpha subunit and computer models of the alpha and beta subunits. The sequence of alpha echicetin is highly similar to the alpha and beta chains of various heterodimeric and homodimeric C-type lectins. Neither of the fully reduced and alkylated alpha or beta subunits of echicetin inhibited the platelet agglutination induced by von Willebrand factor-ristocetin or alpha-thrombin. Earlier reports about the inhibitory activity of reduced and alkylated echicetin beta subunit might have been due to partial reduction of the protein.

The Acropolitan - v. 3, no. 4

In this issue...Mines Basketball, Professor Scott, Glee Club, Wein's, Hotel Finlen, Anderson Carlisle meeting, Metallurgy Laboratory, Oratorical Contest

The Amplifier - v. 3, no. 4

In this issue...Dr. Van Pelt, Anderson-Carlisle Society, Rose Garden Party, Main Hall, Gordon Parker, Magma Yearbook, Berkley Open Pit, Malmstrom Air Force Base

A Facile synthesis of 3-Methylene-4-aryl-1,3,4,5-tetrahydro-benzo[b][1,4] di-azepin-2-ones and 3-arylemethylene-4,5-dihydro-3H-benzo[b][1,4]diazepin-2-ylamines

A simple and convenient synthesis of 3-methylene-4-aryl-1,3,4,5-tetrahydro-benzo[b][1,4] diazepin-2-ones was accomplished by the SN2 nucleophilic substitution of the acetates of Baylis-Hillman adducts of acrylate with 1,2-phenylenediamines followed by base-mediated intramolecular cyclization. On the other hand similar substrates derived from the Baylis-Hillman adducts of acrylonitrile via Pinner’s reaction leads to 3-arylmethylene-4,5-dihydro-3H-benzo[b][1,4]diazepin-2-ylamines in good yields..

Base pairing and miscoding properties of 1,N(6)-ethenoadenine- and 3,N(4)-ethenocytosine-containing RNA oligonucleotides

Two RNA phosphoramidites containing the bases 1,N(6)-ethenoadenine (εA) and 3,N(4)-ethenocytosine (εC) were synthesized. These building blocks were incorporated into two 12-mer oligoribonucleotides for evaluation of the base pairing properties of these base lesions by UV melting curve (Tm) and circular dichroism measurements. The Tm data of the resulting duplexes with the etheno modifications opposing all natural bases showed a substantial destabilization compared to the corresponding natural duplexes, confirming their inability to form base pairs. The coding properties of these lesions were further investigated by introducing them into 31-mer oligonucleotides and assessing their ability to serve as templates in primer extension reactions with HIV, AMV, and MMLV reverse transcriptases (RT). Primer extension reactions showed complete arrest of the incorporation process using MMLV RT and AMV RT, while HIV RT preferentially incorporates dAMP opposite εA and dAMP as well as dTMP opposite εC. The properties of these RNA lesions are discussed in the context of its putative biological role.

Assessment of the Matrix Degenerative Effects of MMP-3, ADAMTS-4 and HTRA1 injected into a bovine Intervertebral Disc Organ Culture Model

Study Design. In vitro study to develop an intervertebral disc degeneration (IDD) organ culture model, using coccygeal bovine intervertebral discs (IVDs) and injection of proteolytic enzymes MMP-3, ADAMTS-4 and HTRA1.Objective. This study aimed to develop an in-vitro model of enzyme-mediated IDD to mimic the clinical outcome in humans for investigation of therapeutic treatment options.Summary of Background Data. Bovine IVDs are comparable to human IVDs in terms of cell composition and biomechanical behavior. Researchers injected papain and trypsin into them to create an IDD model with a degenerated nucleus pulposus (NP) area. They achieved macroscopic cavities as well as a loss of glycosaminoglycans (GAGs). However, none of these enzymes are clinically relevant.Methods. Bovine IVDs were harvested maintaining the endplates. Active forms of MMP-3, ADAMTS-4 and HTRA1 were injected at a dose of 10μg/ml each. Phosphate buffered saline (PBS) was injected as a control. Discs were cultured for 8 days and loaded diurnally (day 1 to day 4 with 0.4 MPa for 16 h) and left under free swelling condition from day 4 to day 8 to avoid expected artifacts due to dehydration of the NP. Outcome parameters included disc height, metabolic cell activity, DNA content, glycosaminoglycan (GAG) content, total collagen content, relative gene expression and histological investigation.Results. The mean metabolic cell activity was significantly lower in the NP area of discs injected with ADAMTS-4 compared to the day 0 control discs. Disc height was decreased following injection with HTRA1, and was significantly correlated with changes in GAG/DNA of the NP tissue. Total collagen content tended to be lower in groups injected with ADAMTS4 and MMP-3.Conclusion. MMP-3, ADAMTS-4 and HTRA1 neither provoked visible matrix degradation nor major shifts in gene expression. However, cell activity was significantly reduced and HTRA1 induced loss of disc height which positively correlated with changes in GAG/DNA content. The use of higher doses of these enzymes or a combination thereof may therefore be necessary to induce disc degeneration

Activity of anidulafungin in a murine model of Candida krusei infection: evaluation of mortality and disease burden by quantitative tissue cultures and measurement of serum (1,3)-beta-D-glucan levels.

Experience with anidulafungin against Candida krusei is limited. Immunosuppressed mice were injected with 1.3 x 10(7) to 1.5 x 10(7) CFU of C. krusei. Animals were treated with saline, 40 mg/kg fluconazole, 1 mg/kg amphotericin B, or 10 and 20 mg/kg anidulafungin for 5 days. Anidulafungin improved survival and significantly reduced the number of CFU/g in kidneys and serum beta-glucan levels.