A New Class of Pentacoordinate Ribonuclease Inhibitors:  Synthesis, Characterization, and Inhibition Studies of Ribonucleoside and Anhydropentofuranose Oxorhenium(V) Complexes

1996 ◽  
Vol 118 (50) ◽  
pp. 12521-12527 ◽  
Author(s):  
Paul Wentworth ◽  
Torsten Wiemann ◽  
Kim D. Janda
Keyword(s):  
New Class ◽  
Inhibition Studies ◽  
Ribonuclease Inhibitors

ChemInform Abstract: Quinone-Annonaceous Acetogenins: Synthesis and Complex I Inhibition Studies of a New Class of Natural Product Hybrids.

ChemInform ◽  
2010 ◽  
Vol 33 (5) ◽  
pp. no-no
Author(s):  
Sabine Arndt ◽  
Ulrich Emde ◽  
Stefan Baeurle ◽  
Thorsten Friedrich ◽  
Lutz Grubert ◽  
...  
Keyword(s):  
Natural Product ◽  
Complex I ◽  
Annonaceous Acetogenins ◽  
New Class ◽  
Inhibition Studies

scholarly journals Mechanistic studies of the agmatine deiminase from Listeria monocytogenes

2016 ◽  
Vol 473 (11) ◽  
pp. 1553-1561 ◽  
Author(s):  
Charles A. Soares ◽  
Bryan Knuckley
Keyword(s):  
Listeria Monocytogenes ◽  
Catalytic Mechanism ◽  
Mechanistic Studies ◽  
New Class ◽  
Enzyme Superfamily ◽  
Agmatine Deiminase ◽  
Inhibition Studies

Mechanistic and inhibition studies of the agmatine deiminase found in Listeria monocytogenes reveal a novel catalytic mechanism for the guanidinium-modifying enzyme superfamily. The results of the present study suggest that a new class of mechanism-based inactivators is needed.

Quinone-Annonaceous Acetogenins: Synthesis and Complex I Inhibition Studies of a New Class of Natural Product Hybrids

2001 ◽  
Vol 7 (5) ◽  
pp. 993-1005 ◽  
Author(s):  
Sabine Arndt ◽  
Ulrich Emde ◽  
Stefan Bäurle ◽  
Thorsten Friedrich ◽  
Lutz Grubert ◽  
...  
Keyword(s):  
Natural Product ◽  
Complex I ◽  
Annonaceous Acetogenins ◽  
New Class ◽  
Inhibition Studies

scholarly journals Low Frequencies of Resistance among Staphylococcus and Enterococcus Species to the Bactericidal DNA Polymerase Inhibitor N3-Hydroxybutyl 6-(3′-Ethyl-4′-Methylanilino) Uracil

2002 ◽  
Vol 46 (12) ◽  
pp. 3770-3775 ◽  
Author(s):  
Michelle M. Butler ◽  
Donna J. Skow ◽  
Ryan O. Stephenson ◽  
Patrick T. Lyden ◽  
William A. LaMarr ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Single Amino Acid ◽  
Resistant Bacteria ◽  
Resistance Development ◽  
Low Frequencies ◽  
New Class ◽  
Polymerase Inhibitor ◽  
Resistant Strains ◽  
Novel Target ◽  
Inhibition Studies

ABSTRACT The 6-anilinouracils (AUs) constitute a new class of bactericidal antibiotics selective against gram-positive (Gr+) organisms. The AU family of compounds specifically inhibits a novel target, replicative DNA polymerase Pol IIIC. Like other antibiotics, AUs can be expected to engender the development of resistant bacteria. We have used a representative AU and clinically relevant strains of Staphylococcus aureus and Enterococcus to determine the frequency and mechanism(s) of resistance development. The frequency of resistance was determined by using N 3-hydroxybutyl 6-(3′-ethyl-4′-methylanilino) uracil (HBEMAU) and commercially available antibiotics at eight times the MICs. For all five Gr+ organisms tested, the frequency of resistance to HBEMAU ranged from 1 × 10−8 to 3 × 10−10. The frequencies of resistance to the antibiotics tested, including rifampin, gentamicin, and ciprofloxacin, were either greater than or equal to those for HBEMAU. In order to understand the mechanism of resistance, HBEMAU-resistant organisms were isolated. MIC assays showed that the organisms had increased resistance to AU inhibitors but not to other families of antibiotics. Inhibition studies with DNA polymerases from HBEMAU-sensitive and -resistant strains demonstrated that the resistance was associated with Pol IIIC. DNA sequence analysis of the entire polC genes from both wild-type and resistant organisms revealed that the resistant organisms had a sequence change that mapped to a single amino acid codon in all strains examined.

scholarly journals Identification and characterization of Thermoplasma acidophilum glyceraldehyde dehydrogenase: a new class of NADP+-specific aldehyde dehydrogenase

2006 ◽  
Vol 397 (1) ◽  
pp. 131-138 ◽  
Author(s):  
Jin Hwa Jung ◽  
Sun Bok Lee
Keyword(s):  
Molecular Mass ◽  
Aldehyde Dehydrogenase ◽  
Aromatic Aldehydes ◽  
Thermoplasma Acidophilum ◽  
Genome Database ◽  
New Class ◽  
Cell Extracts ◽  
Sds Page ◽  
Aldehyde Dehydrogenase Superfamily ◽  
Inhibition Studies

Thermoacidophilic archaea such as Thermoplasma acidophilum and Sulfolobus solfataricus are known to metabolize D-glucose via the nED (non-phosphorylated Entner–Doudoroff) pathway. In the present study, we identified and characterized a glyceraldehyde dehydrogenase involved in the downstream portion of the nED pathway. This glyceraldehyde dehydrogenase was purified from T. acidophilum cell extracts by sequential chromatography on DEAE-Sepharose, Q-Sepharose, Phenyl-Sepharose and Affi-Gel Blue columns. SDS/PAGE of the purified enzyme showed a molecular mass of approx. 53 kDa, whereas the molecular mass of the native protein was 215 kDa, indicating that glyceraldehyde dehydrogenase is a tetrameric protein. By MALDI–TOF-MS (matrix-assisted laser-desorption ionization–time-of-flight MS) peptide fingerprinting of the purified protein, it was found that the gene product of Ta0809 in the T. acidophilum genome database corresponds to the purified glyceraldehyde dehydrogenase. The native enzyme showed the highest activity towards glyceraldehyde, but no activity towards aliphatic or aromatic aldehydes, and no activity when NAD+ was substituted for NADP+. Analysis of the amino acid sequence and enzyme inhibition studies indicated that this glyceraldehyde dehydrogenase belongs to the ALDH (aldehyde dehydrogenase) superfamily. BLAST searches showed that homologues of the Ta0809 protein are not present in the Sulfolobus genome. Possible differences between T. acidophilum (Euryarchaeota) and S. solfataricus (Crenarchaeaota) in terms of the glycolytic pathway are thus expected.

In Situ microscopy of the anodic etching of silicon

1995 ◽  
Vol 53 ◽  
pp. 232-233
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Selective Etching ◽  
Silicon On Insulator ◽  
Second Phase ◽  
Porous Layers ◽  
New Class ◽  
Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

The microtubule associated protein (MAP) tau forms a new class of triple-stranded left-hand helical fibrous protein polymer

1992 ◽  
Vol 50 (1) ◽  
pp. 540-541
Author(s):  
G. C. Ruben ◽  
K. Iqbal ◽  
I. Grundke-Iqbal ◽  
H. Wisniewski ◽  
T. L. Ciardelli ◽  
...  
Keyword(s):  
Axial Ratio ◽  
Normal Structure ◽  
Paired Helical Filaments ◽  
Left Hand ◽  
New Class ◽  
Protein Polymer ◽  
Fibrous Protein ◽  
Protein Map ◽  
Neurotransmitter Transport ◽  
Alzheimer Neurofibrillary Tangles

In neurons, the microtubule associated protein, tau, is found in the axons. Tau stabilizes the microtubules required for neurotransmitter transport to the axonal terminal. Since tau has been found in both Alzheimer neurofibrillary tangles (NFT) and in paired helical filaments (PHF), the study of tau's normal structure had to preceed TEM studies of NFT and PHF. The structure of tau was first studied by ultracentrifugation. This work suggested that it was a rod shaped molecule with an axial ratio of 20:1. More recently, paraciystals of phosphorylated and nonphosphoiylated tau have been reported. Phosphorylated tau was 90-95 nm in length and 3-6 nm in diameter where as nonphosphorylated tau was 69-75 nm in length. A shorter length of 30 nm was reported for undamaged tau indicating that it is an extremely flexible molecule. Tau was also studied in relation to microtubules, and its length was found to be 56.1±14.1 nm.

Study of segregation in La1.8Sr0.2CuO4 superconductor by STEM-EDS microanalysis

1987 ◽  
Vol 45 ◽  
pp. 54-55
Author(s):  
T. F. Kelly ◽  
P. J. Lee ◽  
E. E. Hellstrom ◽  
D. C. Larbalestier
Keyword(s):  
Rare Earth ◽  
High Field ◽  
Transport Current ◽  
Total Thickness ◽  
New Class ◽  
Ceramic Superconductors ◽  
Current Densities ◽  
Group Ii ◽  
Eds Microanalysis

Recently there has been much excitement over a new class of high Tc (>30 K) ceramic superconductors of the form A1-xBxCuO4-x, where A is a rare earth and B is from Group II. Unfortunately these materials have only been able to support small transport current densities 1-10 A/cm2. It is very desirable to increase these values by 2 to 3 orders of magnitude for useful high field applications. The reason for these small transport currents is as yet unknown. Evidence has, however, been presented for superconducting clusters on a 50-100 nm scale and on a 1-3 μm scale. We therefore planned a detailed TEM and STEM microanalysis study in order to see whether any evidence for the clusters could be seen.A La1.8Sr0.2Cu04 pellet was cut into 1 mm thick slices from which 3 mm discs were cut. The discs were subsequently mechanically ground to 100 μm total thickness and dimpled to 20 μm thickness at the center.

Electronic structure studies of conducting polymers by electron energy-loss spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 160-161
Author(s):  
J. Fink
Keyword(s):  
Electronic Structure ◽  
Conducting Polymers ◽  
Conjugated Polymers ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Light Emitting ◽  
One Dimensional ◽  
New Class ◽  
Electrical Conductivities ◽  
Electron Energy Loss

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

Mechanochemical changes on cyclometalated Ir(iii) acyclic carbene complexes – design and tuning of luminescent mechanochromic transition metal complexes

2020 ◽  
Vol 7 (3) ◽  
pp. 786-794 ◽  
Author(s):  
Jingqi Han ◽  
Kin-Man Tang ◽  
Shun-Cheung Cheng ◽  
Chi-On Ng ◽  
Yuen-Kiu Chun ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Carbene Complexes ◽  
New Class

A new class of luminescent cyclometalated Ir(iii) complexes with readily tunable mechanochromic properties derived from the mechanically induced trans-to-cis isomerization have been developed.

Sign in / Sign up

Export Citation Format

Share Document