Stability of Hydrated Methylamine: Structural Characteristics and H₂N···H–O Hydrogen Bonds

Methylamine is the simplest aliphatic amine found in human urine, blood, and tissues. It is thought to play a significant part in central nervous system disturbances observed during renal and hepatic disease. In this work we have investigated the methylamine hydration clusters using a basin hopping (BH) algorithm with the density functional theory (DFT). The results presented herein yield a detailed understanding of the structure and stability for a system consisting of one methylamine molecule and up to seven waters: the most stable geometries arise from a fusion of tetramer or pentamer rings; by the geometrical parameters and topological parameters analysis, the strengths of the H₂N···H–O hydrogen bonds of the global minima increase as the sizes of clusters increase, except for <i>n</i> = 5 where there is a slight fluctuation. This work may shed light on the form mechanism of methylamine existing in organisms and the hydration structures of larger molecules containing amino functional groups and their interaction with the water molecules nearby

Three new Anthraquinones, one new Benzochromene and one new Furfural glycoside from <i>Lasianthus acuminatissimus</i>

<p>Three new anthraquinones, lasianthurin B (1), C (2), lasianthuoside D (3), a new benzochromene, lasianthurin D (4), and a new furfural glycoside, lasianthuoside E (5), together with one known compound 4- hydroxymethyl-2-furaldehyde (6) were isolated from an alcohol extract of the root of <i>Lasianthus acuminatissimus</i>. Their structures were elucidated on the basis of extensive spectroscopic data analysis (including 1D, 2D NMR, X-ray, and MS experiments) and comparsion to literature data.</p

Concave ZnFe₂O₄ Hollow Octahedral Nanocages Derived from Fe-Doped MOF‑5 for High-Performance Acetone Sensing at Low-Energy Consumption

Herein, through a morphology-inherited annealing treatment of a hollow Fe-doped MOF-5 octahedron as the self-sacrificing template, we report the synthesis of concave ZnFe₂O₄ hollow octahedral nanocages as sensing materials, which exhibited high performance, including unprecedented excellent sensitivity, good selectivity, and cyclic stability at ultralow working temperature (120 °C)

EHV-1-induced platelet P-selectin expression requires plasma and exogenous calcium.

<p><b>A</b>: Effect of plasma: Equine platelets in ACD-anticoagulated platelet-rich plasma (PRP), washed platelets (WP) or washed platelets with added ACD-anticoagulated platelet-derived microparticle-depleted plasma (WP+MDP) were exposed for 10 minutes to RacL11 at 1 PFU/cell with PBS and RK lysate negative controls and a thrombin (T, 0.15 U/mL) positive control. Washed platelets did not express P-selectin when exposed to virus unless plasma was present. In contrast, thrombin-induced P-selectin expression was independent of plasma (n = 5). Data represents mean ± SD. * p < 0.001 versus PRP or WP + MDP for RacL11-exposed platelets. <b>B</b>: Effect of calcium: Equine citrate-anticoagulated PRP was exposed to RacL11 at 1 PFU/cell for 10 minutes with increasing calcium concentrations (0 to 2.5 mM), with the above controls. EHV-1-induced P-selectin expression required at least 1 mM of exogenous calcium (n = 3). Data represents mean ± SD. * p < 0.001 versus 1.0, 2.0 or 2.5 mM calcium.</p

Model for EHV-1-induced activation of platelets.

<p>In our model of EHV-1-induced platelet activation, we propose that the virus first binds to platelets, which triggers platelet fragmentation or microvesiculation in a TF- and thrombin-independent manner. Concurrently, factor VII (FVII) forms a complex with TF in the viral envelope and activates factor X (FX), with FXa generating thrombin in the vicinity of or on the surface of platelets. Thrombin generation may be propagated by phosphatidylserine (PS) in the viral envelope. Thrombin binds to protease-activated receptors (PAR) on platelet surfaces, inducing release of α-granules with subsequent surface P-selectin and PS expression and additional microvesiculation. If marked, microvesiculation results in loss of membrane-anchored P-selectin on microparticles. Depending on the viral strain or load, thrombin may be generated on the surface of virus not attached to platelets.</p

EHV-1 induces platelet P-selectin expression and shedding of platelet-derived microparticles in equine platelet-rich plasma.

<p>Platelets were exposed for 10 minutes to RacL11 or Ab4 EHV-1 strains at increasing PFU/cell (0.01, 0.1, 0.5, or 1) with PBS and RK lysate as negative controls and thrombin-convulxin (TC, 0.15 U/mL-0.05 ug/mL) as a positive control. Then the mean percentage ± SD of platelets positive for P-selectin (<b>A</b>) and PDMPs (<b>B</b>) were quantified (n = 8). At the higher PFU/cell of 0.5 and 1, both strains induced P-selectin expression and microvesiculation, along with compaction and narrowing of the platelet event cloud and increased small events on forward and side scatter dotplots (<b>C</b>). Microvesiculation was more prominent with RacL11 (B, C arrow). Exposure to both viruses at 5 PFU/cell replicated these findings, demonstrating a dose-dependent platelet activation response (<b><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0122640#pone.0122640.s001" target="_blank">S1 Fig</a></b>). * p ≤ 0.01 versus PBS or RK negative controls for each strain. ** p < 0.001 versus TC or Ab4 at 0.5 or 1 PFU/cell.</p

Construction and verification of a glycoprotein C (gC) deletion mutant of Ab4.

<p><b>A:</b> An illustrative overview of generation of the deletion mutant in an infectious artificial bacterial chromosome (BAC) containing plaque purified Ab4 (Ab4). A PCR product that harbored the <i>kan</i>_<i>R</i> gene instead of nucleotides 98–1315 of the <i>ORF16</i> gene, which encodes gC, was electroporated into <i>E</i>. <i>coli</i> GS1783 for <i>en passant</i> (two-step) Red recombination. Intermediate colonies were screened and used for the second recombination step. Removal of <i>Kan</i>^<i>R</i> was induced by 1% arabinose resulting in the final construct. <b>B:</b> Identity of the mutant (Ab4GΔgC) was confirmed by restriction enzyme digests. BAC DNA from the parental, intermediate and final constructs was digested with <i>HindIII</i> and separated by 0.8% agarose gel electrophoresis. The intermediate construct harboring <i>Kan</i>^<i>R</i> had an additional band of 6.8 kbp (lower arrow). After resolution, a fragment of 8.6 kbp (upper arrow) containing the <i>ORF16</i> gene disappeared and a fragment of 7.4 kbp in the final mutant appeared. This apparent reduction is in line with the deletion introduced by mutagenesis. <b>C:</b> BAC DNA from Ab4 (wild-type) or Ab4GΔgC was used as the template for PCR using gC primers that span the deleted region (forward: 5’- CTCCGACCAGTGGAGTTATTAT-3’; reverse: 5’- CTACTGTTTTTACCAGCGCTTC-3’). Bands of the predicted size were amplified in either case, thus confirming deletion of gC-encoding sequences in the mutant Ab4GΔgC.</p

Tissue factor mediates EHV-1-induced platelet activation, with no role for virus glycoprotein C.

<p>A goat polyclonal anti-rabbit tissue factor (TF) antibody (anti-TF, 152 ug/mL) abolished P-selectin expression (<b>A</b>) and significantly decreased the numbers of platelet-derived microparticles (PDMP) (<b>B</b>) in equine platelets exposed to RacL11 and Ab4 EHV-1 strains at 1 PFU/cell (n = 6). Data shown is mean ± SD. * p = 0.033 for RacL11 and p = 0.011 for Ab4 versus goat IgG controls. In contrast, platelets still expressed P-selectin (<b>C</b>) and shed PDMPs (<b>D</b>) when exposed to an Ab4-based envelope glycoprotein C deletion mutant (ΔgC) at 1 PFU/cell. The deletion mutant induced stronger vesiculation and lower P-selection translocation than wild type Ab4 (WT) (n = 8). Data shown is mean ± SD. * versus ΔgC mutant.</p

Flow cytometry gating strategy for quantification of platelet-derived microparticles in equine platelet samples.

<p><b>A:</b> Platelet events in citrate-anticoagulated platelet-rich plasma were identified and gated as CD41-positive cells (R1 region) in a CD41 fluorescence versus forward scatter (FSC) dotplot. The R1 region or gate was established on an isotype control for the CD41 antibody. Representative image from platelets exposed to the RacL11 strain of EHV-1 at 1 plaque forming unit (PFU)/cell. <b>B:</b> Platelet-derived microparticles (PDMPs) were defined as small events (<10¹ log FSC units) positive for Annexin V and CD41. The PDMP percentage was obtained from the lower right quadrant of an Annexin V fluorescence versus FSC dotplot of the R1 gate (CD41-positive events), with the quadrants being defined on a negative sample in which 1 mM EDTA was added to the buffer with Annexin V. The PDMP percentage was 0.1% in this representative image of platelets exposed to rabbit kidney 13 (RK) cell lysate at an equivalent volume to 1 PFU/cell (mock-infected negative control). The events in the upper left and right quadrants are platelets that are negative (94.0%) and positive for Annexin V (0.9%), respectively. <b>C</b>: Representative image of PDMP quantification in platelets exposed to RacL11 at 1 PFU/cell. In this sample, there are 12.1% PDMP (lower right quadrant) and 22.1% of platelets are weakly positive for Annexin V (upper right quadrant).</p

Equid herpesvirus type 1 generates factor Xa (FXa) in a dose-dependent manner.

<p>Factor Xa generation (nM) was measured with purified virus at different plaque forming units/cell (PFU/cell) using a one stage amidolytic assay with exogenous human FVIIa (1 nM) and FX (75 nM) and a chromogenic FXa substrate (n = 4). The FXa concentration was derived from comparing the rate of substrate cleavage in the sample (Vmax) to a standard curve of serially diluted purified human FXa. Factor Xa generation was below the linearity of the assay (0.17 nM FXa) in negative controls (samples without added FVIIa or FX or RK lysate with all reagents).</p><p>* Below assay linearity.</p><p>Equid herpesvirus type 1 generates factor Xa (FXa) in a dose-dependent manner.</p