Comparison of the CopB systems of plasmids R1 and Co1V2-K94: A single base alteration in CopB gene is responsible for the increased copy number of the low copy number plasmid CoIV2-K94

Summary We have isolated a deletion mutation and a point mutation in the copB gene of the replication region Repl of the IncFI plasmid Co1V2-K94. Subsequently, this copB gene with and without point mutation was cloned and sequenced, and the point mutation was mapped in the coding region of copB with a change of one amino acid from arginine to serine. Furthermore, this copB mutant had an approximately 10-fold increase in copy number. The CopB-phenotype of Co1V2-K94 could be complemented in trans by the copB gene of coresident IncFII plasmids such as R1 and R538, but not R100, suggesting that ColV2-K94 and R1 or R538 contain the same copB allele.     

Speed Breeding Opportunities and Challenges for Crop Improvement

Journal of Plant Growth Regulation - Crop improvement in light of the rapidly changing climate and the increasing human population continues to be one of the primary concerns for researchers across...     

Effects of anatomic variability on blood flow and pressure gradients in the pulmonary capillaries

Dhadwal, Amit, Barry Wiggs, Claire M. Doerschuk, and RogerD. Kamm. Effects of anatomic variability on blood flow and pressure gradients in the pulmonary capillaries. J. Appl. Physiol. 83(5): 1711-1720, 1997.Atheoretical model is developed to simulate the flow of blood throughthe capillary network in a single alveolar septum. The objective is tostudy the influence of random variability in capillary dimension andcompliance on flow patterns and pressures within the network. Thecapillary bed is represented as an interconnected rectangular grid ofcapillary segments and junctions; blood flow is produced by applying apressure gradient across the network. Preferred flow channels are shownto be a natural consequence of random anatomic variability, the effectof which is accentuated at low transcapillary pressures. Thedistribution of pressure drops across single capillary segments widenswith increasing network variability and decreasing capillary transmuralpressure. Blockage of one capillary segment causes the pressure dropacross that segment to increase by 60%, but the increase falls to<10% at a distance of three segments. The factors that causenonuniform capillary blood flow through the capillary network arediscussed.

     

Stereoselective enzymatic hydrolysis of (exo,exo)-7-oxabicyclo[2.2.1]heptane-2,3-dimethanol diacetate ester in a biphasic system

Summary A key chiral intermediate lactol(3)[3aS (3a,4,7,7a)]-hexahydro-4,7-epoxy-isobenzofuran-1 (3H)-one was prepared for the total synthesis of a new thromboxane antagonist. The stereoselective hydrolysis of (exo,exo)-7-oxabicyclo[2.2.1]heptane-2,3-dimethanol, diacetate ester (1) to the corresponding chiral monoacetate ester (2) was carried out with lipases, among which Amano P-30 lipase from Pseudomonas sp. was most effective since it gave the desired enantiomer of monoacetate ester. A yield of 75 mol% and optical purity of >99% was obtained when the reaction was conducted in a biphasic system with 10% toluene at 5 g/l of the substrate. Lipase P-30 was immobilized on Accurel polypropylene (PP) and the immobilized enzyme was reused (five cycles) without loss of enzyme activity, productivity or optical purity. The reaction process was scaled-up to 80 1 (400 g substrate) and monoacetate (2) was isolated in 80 mol% yield with 99.3% optical purity as determined by chiral HPLC and nuclear magnetic resonance (NMR) analysis. A gas chromatography of 99.5% and specific rotation, []_D of -7.6° was obtained. The chiral monoacetate ester (2) was oxidized to its corresponding aldehyde and subsequently hydrolyzed to give lactol (3).     

The growth hormone binding protein as a paradigm of the erythropoietin superfamily of receptors.

The growth hormone (GH) receptor belongs to a novel receptor family which shares significant amino-acid sequence homology and includes prolactin receptors, erythropoietin receptors and several cytokines' receptors. GH and three other members of this family of receptors have been shown to have circulating soluble forms. The present review summarizes our knowledge on receptor related binding proteins, discusses their possible biological effects and suggests their use in novel assays for their ligands. The GH-binding protein (GH-BP) was the first to have been described and is used as a model for the concept. A series of indirect pieces of evidence suggest that the measurement of circulating GH-BP may enable an evaluation of the GH-receptor. When covalently bound to GH, GH-BP has been shown to slow the clearance of GH. On the other hand GH-BP competes with the GH-receptor for GH binding and, thus, diminishes the biological effect of GH. We suggest a biological role for GH-BP as follows: an increase in the availability of GH results not only in the upregulation of the GH-receptor but also in increased turnover of this receptor, its internalization and recycling. This is followed by a concomitant increase in GH-BP which, in turn, mitigates the effect of GH by competing with the receptor on GH binding. The extracellular domain of the GH-receptor is homologous, to a large extent, with the sequence of several receptors for hormones and cytokines, which have recently been cloned.(ABSTRACT TRUNCATED AT 250 WORDS)     

Glutamate dehydrogenase deficiency disrupts glutamate homeostasis in hippocampus and prefrontal cortex and impairs recognition memory

Glutamate Dehydrogenase 1 (GDH), encoded by the Glud1 gene in rodents, is a mitochondrial enzyme critical for maintaining glutamate homeostasis at the tripartite synapse. Our previous studies indicate that the hippocampus may be particularly vulnerable to GDH deficiency in central nervous system (CNS). Here, we first asked whether mice with a homozygous deletion of Glud1 in CNS (CNS‐Glud1 ?/? mice) express different levels of glutamate in hippocampus, and found elevated glutamate as well as glutamine in dorsal and ventral hippocampus, and increased glutamine in medial prefrontal cortex (mPFC). l ‐serine and d ‐serine, which contribute to glutamate homeostasis and NMDA receptor function, are increased in ventral but not dorsal hippocampus, and in mPFC. Protein expression levels of the GABA synthesis enzyme glutamate decarboxylase (GAD) GAD67 were decreased in the ventral hippocampus as well. Behavioral analysis revealed deficits in visual, spatial and social novelty recognition abilities, which require intact hippocampal‐prefrontal cortex circuitry. Finally, hippocampus‐dependent contextual fear retrieval was deficient in CNS‐Glud1 ?/? mice, and c‐Fos expression (indicative of neuronal activation) in the CA1 pyramidal layer was reduced immediately following this task. These data point to hippocampal subregion‐dependent disruption in glutamate homeostasis and excitatory/inhibitory balance, and to behavioral deficits that support a decline in hippocampal‐prefrontal cortex connectivity. Together with our previous data, these findings also point to different patterns of basal and activity‐induced hippocampal abnormalities in these mice. In sum, GDH contributes to healthy hippocampal and PFC function; disturbed GDH function is relevant to several psychiatric and neurological disorders.     

A Comprehensive Review of Animal Models for Coronaviruses: SARS-CoV-2, SARS-CoV,and MERS-CoV

The recent outbreak of coronavirus disease(COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) has already affected a large population of the world. SARS-CoV-2 belongs to the same family of severe acute respiratory syndrome coronavirus(SARS-CoV) and Middle East respiratory syndrome coronavirus(MERSCoV). COVID-19 has a complex pathology involving severe acute respiratory infection, hyper-immune response, and coagulopathy. At present, there is no therapeutic drug or vaccine approved for the disease. There is an urgent need for an ideal animal model that can reflect clinical symptoms and underlying etiopathogenesis similar to COVID-19 patients which can be further used for evaluation of underlying mechanisms, potential vaccines, and therapeutic strategies. The current review provides a paramount insight into the available animal models of SARS-CoV-2, SARS-CoV, and MERS-CoV for the management of the diseases.     

Micropropagation,encapsulation, and conservation of Decalepis salicifolia,a vanillin isomer containing medicinal and aromatic plant

In Vitro Cellular & Developmental Biology - Plant - An efficient in vitro propagation and synthetic seed production protocol was established for the conservation of Decalepis salicifolia (Bedd....     

Esterase activity and interaction of human hemoglobin with diclofenac sodium: A spectroscopic and molecular docking study

To get an idea about the pharmacokinetics and pharmacodynamics, it is important to study the drug‐protein interaction. Therefore, herein, we studied the interaction of diclofenac sodium (DIC) with human hemoglobin. The binding study of nonsteroidal antiinflammatory drug, DIC with human hemoglobin (HHB) was done by utilizing fluorescence, UV–visible, time‐resolved fluorescence and far‐UV circular dichroism spectroscopy (CD). Various thermodynamic parameters such as enthalpy change (ΔH), entropy change (ΔS), and Gibbs free energy change (ΔG) were also calculated. CD results showed that DIC induces secondary structure change in HHB. Fluorescence resonance energy transfer was also performed. Additionally, it was also observed that DIC inhibits the esterase‐like enzymatic activity of HHB via competitive inhibition.