scholarly journals Inhibition of Rumen Protozoa by Specific Inhibitors of Lysozyme and Peptidases in vitro

2019 ◽  
Vol 10 ◽  
Author(s):  
Tansol Park ◽  
Huiling Mao ◽  
Zhongtang Yu
Keyword(s):  
Rumen Protozoa ◽  
Specific Inhibitors

scholarly journals Yeast-based automated high-throughput screens to identify anti-parasitic lead compounds

Open Biology ◽  
2013 ◽  
Vol 3 (2) ◽  
pp. 120158 ◽  
Author(s):  
Elizabeth Bilsland ◽  
Andrew Sparkes ◽  
Kevin Williams ◽  
Harry J. Moss ◽  
Michaela de Clare ◽  
...  
Keyword(s):  
Side Effects ◽  
Trypanosoma Brucei ◽  
Fluorescent Proteins ◽  
Screening Method ◽  
Lead Compounds ◽  
Dihydrofolate Reductases ◽  
Parasitic Activity ◽  
High Throughput Screens ◽  
Specific Inhibitors

We have developed a robust, fully automated anti-parasitic drug-screening method that selects compounds specifically targeting parasite enzymes and not their host counterparts, thus allowing the early elimination of compounds with potential side effects. Our yeast system permits multiple parasite targets to be assayed in parallel owing to the strains’ expression of different fluorescent proteins. A strain expressing the human target is included in the multiplexed screen to exclude compounds that do not discriminate between host and parasite enzymes. This form of assay has the advantages of using known targets and not requiring the in vitro culture of parasites. We performed automated screens for inhibitors of parasite dihydrofolate reductases, N -myristoyltransferases and phosphoglycerate kinases, finding specific inhibitors of parasite targets. We found that our ‘hits’ have significant structural similarities to compounds with in vitro anti-parasitic activity, validating our screens and suggesting targets for hits identified in parasite-based assays. Finally, we demonstrate a 60 per cent success rate for our hit compounds in killing or severely inhibiting the growth of Trypanosoma brucei , the causative agent of African sleeping sickness.

scholarly journals Akt Interacts with Usutu Virus Polymerase, and Its Activity Modulates Viral Replication

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 244
Author(s):  
Laura Albentosa-González ◽  
Rosario Sabariegos ◽  
Armando Arias ◽  
Pilar Clemente-Casares ◽  
Antonio Mas
Keyword(s):  
Public Health ◽  
Confocal Microscopy ◽  
Viral Replication ◽  
Insufficient Data ◽  
Health Concerns ◽  
Usutu Virus ◽  
A Cell ◽  
Infected Cells ◽  
Specific Inhibitors

Usutu virus (USUV) is a flavivirus that mainly infects wild birds through the bite of Culex mosquitoes. Recent outbreaks have been associated with an increased number of cases in humans. Despite being a growing source of public health concerns, there is yet insufficient data on the virus or host cell targets for infection control. In this work we have investigated whether the cellular kinase Akt and USUV polymerase NS5 interact and co-localize in a cell. To this aim, we performed co-immunoprecipitation (Co-IP) assays, followed by confocal microscopy analyses. We further tested whether NS5 is a phosphorylation substrate of Akt in vitro. Finally, to examine its role in viral replication, we chemically silenced Akt with three inhibitors (MK-2206, honokiol and ipatasertib). We found that both proteins are localized (confocal) and pulled down (Co-IP) together when expressed in different cell lines, supporting the fact that they are interacting partners. This possibility was further sustained by data showing that NS5 is phosphorylated by Akt. Treatment of USUV-infected cells with Akt-specific inhibitors led to decreases in virus titers (>10-fold). Our results suggest an important role for Akt in virus replication and stimulate further investigations to examine the PI3K/Akt/mTOR pathway as an antiviral target.

Systematic analysis and integrative discovery of active-site subpocket-specific dehydroquinate synthase inhibitors combating antibiotic-resistant Staphylococcus aureus infection

2018 ◽  
Vol 16 (06) ◽  
pp. 1850027
Author(s):  
Quanfeng Liu ◽  
Liping Li ◽  
Fei Xu
Keyword(s):  
Staphylococcus Aureus ◽  
Active Site ◽  
Shikimate Pathway ◽  
In Vitro Susceptibility ◽  
Systematic Analysis ◽  
Antibiotic Resistant ◽  
Enzyme Active Site ◽  
Specific Inhibitors ◽  
Dehydroquinate Synthase

Shikimate pathway plays an essential role in the biosynthesis of aromatic amino acids in various plants and bacteria, which consists of seven key enzymes and they are all attractive targets for antibacterial agent development due to their absence in humans. The Staphylococcus aureus dehydroquinate synthase (SaDHQS) is involved in the second step of shikimate pathway, which catalyzes the NAD[Formula: see text]-dependent conversion of 3-deoxy-D-arabino-heptulosonate-7-phosphate to dehydroquinate via multiple steps. The enzyme active site can be characterized by two spatially separated subpockets 1 and 2, which represent the reaction center of substrate adduct with NAD[Formula: see text] nicotinamide moiety and the assistant binding site of NAD[Formula: see text] adenine moiety, respectively. In silico virtual screening is performed against a biogenic compound library to discover SaDHQS subpocket-specific inhibitors, which were then tested against both antibiotic-sensitive and antibiotic-resistant S. aureus strains by using in vitro susceptibility test. The activity profile of hit compounds has no considerable difference between the antibiotic-sensitive and -resistant strains. The subpocket 1-specific inhibitors exhibit a generally higher activity than subpocket 2-specific inhibitors, and they also hold a strong selectivity between their cognate and noncognate subpockets. Dynamics and energetics analyses reveal that the SaDHQS active site prefers to interact with amphipathic and polar inhibitors by forming multiple hydrogen bonds and van der Waals packing at the complex interfaces of the two subpockets with their cognate inhibitors.

scholarly journals Contribution of rumen protozoa to fibre degradation and cellulase activity in vitro

1988 ◽  
Vol 53 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Huub J. Gijzen ◽  
Henk J. Lubberding ◽  
Martin J.T. Gerhardus ◽  
Godfried D. Vogels
Keyword(s):  
Cellulase Activity ◽  
Rumen Protozoa ◽  
Fibre Degradation

214 COX-2 specific inhibitors demonstrate a cytotoxic effect independent of COX-2 protein status in vitro

Lung Cancer ◽  
2006 ◽  
Vol 54 ◽  
pp. S52
Author(s):  
S.L. O'Kaneq ◽  
L. Cawkwell ◽  
J. Greenman ◽  
M.J. Lind
Keyword(s):  
Cytotoxic Effect ◽  
Protein Status ◽  
Cox 2 ◽  
Specific Inhibitors

Matrix metalloproteinases mediate the metastatic phenotype ofTheileria annulata-transformed cells

Parasitology ◽  
1996 ◽  
Vol 113 (5) ◽  
pp. 449-455 ◽  
Author(s):  
R. E. Adamson ◽  
F. R. Hall
Keyword(s):  
Marked Reduction ◽  
Tissue Inhibitor Of Metalloproteinase ◽  
Transformed Cells ◽  
Pathological Features ◽  
Metastatic Phenotype ◽  
Infected Cells ◽  
Metalloproteinase 9 ◽  
Metalloproteinase Activity ◽  
Specific Inhibitors

SUMMARYTheileria annulatainfects and reversibly transforms bovine leucocytes. The parasite-transformed cells are immortalized, metastatic and express a number of metalloproteinases including matrix metalloproteinase 9 which they secrete. All the metalloproteinases observed on substrate gels are inhibited by tissue inhibitor of metalloproteinase 1 and 4 synthetic inhibitors BB94, GM6001, BRL29808AI and Ro31–4724. We have adapted anin vitroassay for metastatic behaviour that measures the ability of parasitized cells to cross reconstituted basement membrane, Matrigel™. Using this we demonstrated that macroschizont-infected cells are invasivein vitroand that their invasive properties can be almost eliminated by the same specific inhibitors of metalloproteinases as used in the substrate gels. This demonstrates that the metastatic behaviour of the infected cells is due in part to metalloproteinase activity and strongly suggests a role for the metalloproteinases we observed on gels. This is further supported by the fact that an attenuated vaccine line which shows much reduced metalloproteinase activity also exhibits a marked reduction in metastatic behaviour. We suggest that these metalloproteinases are virulence factors mediating some pathological features of the disease and their loss in the vaccine line could provide an explanation for attenuation.

Tropical forage trees with low potential defaunating capacity

2005 ◽  
Vol 2005 ◽  
pp. 221-221
Author(s):  
G. E. Monforte Briceño ◽  
C. A. Sandoval Castro ◽  
C. M. Capetillo Leal ◽  
L. Ramírez Avilés
Keyword(s):  
Batch Culture ◽  
Culture System ◽  
Potential Effect ◽  
Rumen Protozoa ◽  
Tropical Forage ◽  
Livestock Feeding ◽  
The Tropics ◽  
Tropical Systems

Forage trees are commonly use for livestock feeding in the tropics. It is known that some species can affect the rumen protozoa population (Odenyoet al., 1997). However, little is known about the potential effect upon rumen protozoa of several species which are also use as feed in tropical systems. The objective of the experiment was to assess the defaunating capacity of forage trees. In companion reports (Monforteet al., 2005) we reported plants with a potential defaunating effect as evaluated under an in vitro batch culture system (Sandovalet al., 2005). Here we present those plants which did not have or had low effect on protozoa population in anin vitroculture.

Glutamylation of methotrexate in hepatoma cells in vitro: Regulation and the development of specific inhibitors

1985 ◽  
Vol 23 ◽  
pp. 13-23 ◽  
Author(s):  
John Galivan ◽  
Zenia Nimec ◽  
James K. Coward ◽  
John J. McGuire
Keyword(s):  
Hepatoma Cells ◽  
Specific Inhibitors

Influence of Rumen Protozoa and Bacteria upon Cellulose Digestion In Vitro

1966 ◽  
Vol 25 (3) ◽  
pp. 609-612 ◽  
Author(s):  
R. D. Yoder ◽  
Allen Trenkle ◽  
Wise Burroughs
Keyword(s):  
Cellulose Digestion ◽  
Rumen Protozoa

scholarly journals An Antiviral Peptide Inhibitor That Is Active against Picornavirus 2A Proteinases but Not Cellular Caspases

2006 ◽  
Vol 80 (19) ◽  
pp. 9619-9627 ◽  
Author(s):  
Luiza Deszcz ◽  
Regina Cencic ◽  
Carla Sousa ◽  
Ernst Kuechler ◽  
Tim Skern
Keyword(s):  
Initiation Factor ◽  
Caspase Inhibitor ◽  
Wild Type ◽  
Caspase 9 ◽  
General Caspase Inhibitor ◽  
Infected Cells ◽  
Antiviral Peptide ◽  
Specific Inhibitors

ABSTRACT The replication of many viruses is absolutely dependent on proteolytic cleavage. Infected cells also use this biological mechanism to induce programmed cell death in response to viral infection. Specific inhibitors for both viral and cellular proteases are therefore of vital importance. We have recently shown that the general caspase inhibitor zVAD.fmk inhibits not only caspases, but also the 2A pro of human rhinoviruses (HRVs) (L. Deszcz, J. Seipelt, E. Vassilieva, A. Roetzer, and E. Kuechler, FEBS Lett. 560:51-55, 2004). Here, we describe a derivative of zVAD.fmk that inhibits HRV2 2A pro but that has no effect on caspase 9. This gain in specificity was achieved by replacing the aspartic acid of zVAD.fmk with methionine to generate zVAM.fmk. Methionine was chosen because an oligopeptide with methionine at the P1 position was a much better substrate than an oligopeptide with an alanine residue, which is found at the P1 position of the wild-type HRV2 2A pro cleavage site. zVAM.fmk inhibits the replication of HRV type 2 (HRV2), HRV14, and HRV16. In contrast to zVAD.fmk, however, zVAM.fmk did not inhibit apoptosis induced by puromycin in HeLa cells. zVAM.fmk inhibited in vitro the intermolecular cleavage of eukaryotic initiation factor 4GI (eIF4GI) by HRV2 2A pro at nanomolar concentrations. However, much higher concentrations of zVAM.fmk were required to inhibit HRV14 2A pro cleavage of eIF4GI. In contrast, intramolecular self-processing of HRV14 2A pro was much more susceptible to inhibition by zVAM.fmk than that of HRV2 2A pro , suggesting that zVAM.fmk inhibits HRV2 and HRV14 replication by targeting different reactions of the same proteinase.

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