scholarly journals Membrane-bound dd-carboxypeptidases from Bacillus megaterium KM. General properties, substrate specificity and sensitivity to penicillins, cephalosporins and peptide inhibitors of the activity at pH5

1974 ◽  
Vol 143 (2) ◽  
pp. 391-402 ◽  
Author(s):  
Teresa Diaz-Mauriño ◽  
Manuel Nieto ◽  
Harold R. Perkins
Keyword(s):  
Ionic Strength ◽  
Substrate Specificity ◽  
Bacillus Megaterium ◽  
Peptide Inhibitors ◽  
Side Chain ◽  
Natural Substrate ◽  
Bivalent Cation ◽  
Specificity And Sensitivity ◽  
Wide Range ◽  
Membrane Bound

1. The membrane from Bacillus megaterium KM contained a dd-carboxypeptidase with optimum activity under the following conditions: pH5.2, bivalent cation, 3mm; ionic strength, 40mm; temperature, 35°C. It was inactivated by treatment with p-chloromercuribenzoate but was fairly insensitive to 2-mercaptoethanol. 2. The enzyme was inhibited by penicillins and cephalosporins. The inhibition of this enzyme was partially reversed on dialysis but 0.2m-2-mercaptoethanol could neither prevent nor reverse the inhibition. 3. The enzyme was extremely sensitive to changes in the configuration and size of the side chain of the C-terminal dipeptide of the substrate. An aliphatic side chain of a well-defined length and polarity was required in the residue that precedes the C-terminal dipeptide. 4. The enzyme was inhibited by a wide range of analogues of the peptidic portion of the natural substrate.

scholarly journals Degradation Potential of the Nonylphenol Monooxygenase of Sphingomonas sp. NP5 for Bisphenols and Their Structural Analogs

2020 ◽  
Vol 8 (2) ◽  
pp. 284 ◽  
Author(s):  
Masahiro Takeo ◽  
Junichi Akizuki ◽  
Aika Kawasaki ◽  
Seiji Negoro
Keyword(s):  
Substrate Specificity ◽  
Cell Suspension ◽  
Structural Similarity ◽  
Side Chain ◽  
Bisphenol S ◽  
Bisphenol F ◽  
Degrading Bacterium ◽  
Monooxygenase Gene ◽  
Wide Range ◽  
Endocrine Disrupting

The nonylphenol-degrading bacterium Sphingomonas sp. strain NP5 has a very unique monooxygenase that can attack a wide range of 4-alkylphenols with a branched side chain. Due to the structural similarity, it can also attack bisphenolic compounds, which are very important materials for the synthesis of plastics and resins, but many of them are known to or suspected to have endocrine disrupting effects to fish and animals. In this study, to clarify the substrate specificity of the enzyme (NmoA) for bisphenolic compounds, degradation tests using the cell suspension of Pseudomonas putida harboring the nonylphenol monooxygenase gene (nmoA) were conducted. The cell suspension degraded several bisphenols including bisphenol F, bisphenol S, 4,4′-dihydroxybenzophenone, 4,4′-dihydroxydiphenylether, and 4,4′-thiodiphenol, indicating that this monooxygenase has a broad substrate specificity for compounds with a bisphenolic structure.

scholarly journals SARS-CoV-2 specific antibody and neutralization assays reveal the wide range of the humoral immune response to virus

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mikail Dogan ◽  
Lina Kozhaya ◽  
Lindsey Placek ◽  
Courtney Gunter ◽  
Mesut Yigit ◽  
...  
Keyword(s):  
Specific Antibody ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
High Specificity ◽  
Spike Protein ◽  
Humoral Immune ◽  
Specificity And Sensitivity ◽  
Wide Range ◽  
Specific Igg ◽  
Negative Controls

AbstractDevelopment of antibody protection during SARS-CoV-2 infection is a pressing question for public health and for vaccine development. We developed highly sensitive SARS-CoV-2-specific antibody and neutralization assays. SARS-CoV-2 Spike protein or Nucleocapsid protein specific IgG antibodies at titers more than 1:100,000 were detectable in all PCR+ subjects (n = 115) and were absent in the negative controls. Other isotype antibodies (IgA, IgG1-4) were also detected. SARS-CoV-2 neutralization was determined in COVID-19 and convalescent plasma at up to 10,000-fold dilution, using Spike protein pseudotyped lentiviruses, which were also blocked by neutralizing antibodies (NAbs). Hospitalized patients had up to 3000-fold higher antibody and neutralization titers compared to outpatients or convalescent plasma donors. Interestingly, some COVID-19 patients also possessed NAbs against SARS-CoV Spike protein pseudovirus. Together these results demonstrate the high specificity and sensitivity of our assays, which may impact understanding the quality or duration of the antibody response during COVID-19 and in determining the effectiveness of potential vaccines.

scholarly journals Intracellular Ionic Strength Sensing Using NanoLuc

2021 ◽  
Vol 22 (2) ◽  
pp. 677
Author(s):  
Tausif Altamash ◽  
Wesam Ahmed ◽  
Saad Rasool ◽  
Kabir H. Biswas
Keyword(s):  
Thermal Stability ◽  
Phase Separation ◽  
Drug Discovery ◽  
Ionic Strength ◽  
Cellular Signaling ◽  
Live Cells ◽  
Protein Activity ◽  
Cellular Survival ◽  
Cellular Processes ◽  
Wide Range

Intracellular ionic strength regulates myriad cellular processes that are fundamental to cellular survival and proliferation, including protein activity, aggregation, phase separation, and cell volume. It could be altered by changes in the activity of cellular signaling pathways, such as those that impact the activity of membrane-localized ion channels or by alterations in the microenvironmental osmolarity. Therefore, there is a demand for the development of sensitive tools for real-time monitoring of intracellular ionic strength. Here, we developed a bioluminescence-based intracellular ionic strength sensing strategy using the Nano Luciferase (NanoLuc) protein that has gained tremendous utility due to its high, long-lived bioluminescence output and thermal stability. Biochemical experiments using a recombinantly purified protein showed that NanoLuc bioluminescence is dependent on the ionic strength of the reaction buffer for a wide range of ionic strength conditions. Importantly, the decrease in the NanoLuc activity observed at higher ionic strengths could be reversed by decreasing the ionic strength of the reaction, thus making it suitable for sensing intracellular ionic strength alterations. Finally, we used an mNeonGreen–NanoLuc fusion protein to successfully monitor ionic strength alterations in a ratiometric manner through independent fluorescence and bioluminescence measurements in cell lysates and live cells. We envisage that the biosensing strategy developed here for detecting alterations in intracellular ionic strength will be applicable in a wide range of experiments, including high throughput cellular signaling, ion channel functional genomics, and drug discovery.

scholarly journals Is Ultrasonography Efficient for the Detection of the Zygomatic Arch, Nasal Bone and Cartilage Fractures?

2020 ◽  
Vol 14 (1) ◽  
pp. 178-183
Author(s):  
Amir Eskandarloo ◽  
Atena karimi ◽  
Abbas Shokri ◽  
Jalal Poorolajal ◽  
Mohammad Hosseinipanah
Keyword(s):  
Bone Fractures ◽  
Imaging Modality ◽  
Nasal Bone ◽  
Kappa Coefficient ◽  
Zygomatic Arch ◽  
Nasal Cartilage ◽  
Specificity And Sensitivity ◽  
Wide Range ◽  
Linear Probe ◽  
And Cartilage

Background: The high incidence of nasal and zygomatic arch fractures highlights the need for an accurate imaging modality for their detection. The superimposition of structures is a major problem in conventional radiography. Ultrasonography is a low-cost imaging modality with a wide range of applications, that does not employ ionizing radiation. This study aimed to assess the efficacy of ultrasonography for the detection of the zygomatic arch and nasal bone fractures. Materials and Methods: This study was conducted on 16 sheep heads. Artificial fractures were created in some parts of the zygomatic arch, dorsum and lateral wall of the nose, and nasal cartilage. All sheep heads underwent Cone-Beam Computed Tomography (CBCT) to ensure the presence of a fracture. Next, the lateral nasal and submentovertex radiographs were obtained, and ultrasonography was performed with a 12-15 MHz linear probe. Ultrasonography and radiography were repeated after 1 week to assess their reproducibility by calculating the kappa coefficient. Data were analyzed using Stata 11 software and Chi-square test. Results: The specificity and sensitivity of ultrasonography ranged from 87% to 100%, and 50% to 75%, respectively. The specificity and sensitivity of radiography ranged from 87% to 100%, and 62% to 87%, respectively. The differences between the two imaging modalities were not statistically significant (p>0.05). The kappa coefficient ranged from 46% to 100% for ultrasonography and 44% to 87% for radiography. Conclusion: Ultrasonography seemed useful for the detection of displaced bone and cartilage fractures. For non-displaced fractures, US is not recommended.

scholarly journals The Role of Exosomes in the Crosstalk between Adipocytes and Liver Cancer Cells

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1988
Author(s):  
Leslimar Rios-Colon ◽  
Elena Arthur ◽  
Suryakant Niture ◽  
Qi Qi ◽  
John T. Moore ◽  
...  
Keyword(s):  
Liver Cancer ◽  
Cancer Cells ◽  
Bioactive Materials ◽  
Liver Cancer Cells ◽  
Secreted Factors ◽  
Wide Range ◽  
Pathophysiological Role ◽  
Inflammatory State ◽  
Membrane Bound

Exosomes are membrane-bound extracellular vesicles (EVs) that transport bioactive materials between cells and organs. The cargo delivered by exosomes can alter a wide range of cellular responses in recipient cells and play an important pathophysiological role in human cancers. In hepatocellular carcinoma (HCC), for example, adipocyte- and tumor-secreted factors contained in exosomes contribute to the creation of a chronic inflammatory state, which contributes to disease progression. The exosome-mediated crosstalk between adipocytes and liver cancer cells is a key aspect of a dynamic tumor microenvironment. In this review, we summarize the role of increased adiposity and the role of adipocyte-derived exosomes (AdExos) and HCC-derived exosomes (HCCExos) in the modulation of HCC progression. We also discuss recent advances regarding how malignant cells interact with the surrounding adipose tissue and employ exosomes to promote a more aggressive phenotype.

scholarly journals Membrane order and ionic strength modulation of the inhibition of the membrane-bound acetylcholinesterase by epigallocatechin‑3‑gallate

2019 ◽  
Vol 1861 (1) ◽  
pp. 170-177 ◽  
Author(s):  
Paula B. Salazar ◽  
Fernando G. Dupuy ◽  
Alejandro de Athayde Moncorvo Collado ◽  
Carlos J. Minahk
Keyword(s):  
Ionic Strength ◽  
Membrane Order ◽  
Membrane Bound
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