Characterization of Biosynthesized Silver Nanoparticles Using Lactobacillus rhamnosus GG and its In Vitro Assessment Against Colorectal Cancer Cells

Silver nanoparticles are the most desirable nanoparticles broadly used in diverse fields. This study intends to investigate the anticancer properties of synthesized silver/Lactobacillus rhamnosus GG nanoparticles (Ag-LNPs) as a reducing and stabilizing agent in the synthesis process. To prepare silver/Lactobacillus rhamnosus GG nanoparticles, 1 mg/ml cell lysate of Lactobacillus rhamnosus GG and 1 mM silver nitrate solution were mixed and incubated for 72 h. XRD, FTIR, and TEM methods were used for nanoparticle characterization. MTT assay and annexin/PI staining were employed to analyze the toxicity and apoptotic cells levels of Ag-LNPs, respectively. TEM showed that these nanoparticles are spherical shaped about 233 nm in size. FTIR spectroscopy demonstrated that Ag-LNPs were functionalized with biomolecules. XRD pattern showed high purity and face-centered crystal structure of Ag-LNPs. MTT assay revealed that the percentages of HT-29 live cells significantly reduced in the high concentration of Ag-LNPs. Annexin/PI staining showed that these nanoparticles could lead HT-29 cells to apoptosis. This study showed the new Ag-LNP-synthesizing method using Lactobacillus rhamnosus GG as a cost-effective and efficient approach. Also, it showed that these nanoparticles can be considered as a potential active agent for biomedical applications and drug delivery due to their anticancer activities.

     

Stereochemical course of the biosynthesis of 1-aminocyclopropane-1-carboxylic acid. I. Role of the asymmetric sulfonium pole and the α-amino acid center

The substrate stereospecificity of 1-aminocyclopropane-1-carboxylic acid synthase, a pyridoxal phosphate-containing enzyme, from the pericarp tissue of $\text{Lycopersicon esculentum}$ (tomatoes) was studied using the various stereoisomers of $\text{S}$-adenosylmethionine (AdoMet) at both the sulfonium pole and the amino acid center. The data indicate that only the naturally occurring isomer (?)Ado-L-Met acts as substrate (Km = 20±5 μM). Both (±)Ado-D-Met and (+)Ado-L-Met were inactive as substrates. The (+)Ado-L-Met (Ki = 15±5 μM) was found to be a potent inhibitor of ACC synthase whereas (±)Ado-D-Met (Ki = 70±20 μM) was less active as an inhibitor. This active isomer has the ($\text{S}$) configuration at both the sulfur and the α-carbon of the amino acid portion of AdoMet.     

Towards a phylogeny for Astragalus section Caprini (Fabaceae) and its allies based on nuclear and plastid DNA sequences

We conducted phylogenetic analyses of the sect. Caprini and its closely related sections within Astragalus. Analyses of a combined dataset including nrDNA ETS and three cpDNA markers using maximum parsimony and Bayesian inference from 44 species of sect. Caprini and its allied taxa yielded congruent relationships among several major lineages. These results largely disagree with previously recognized taxonomic groups, most notably in the following ways: (1) subsects. Caprini and Purpurascentes of sect. Caprini are not natural groups; (2) sects. Alopecuroidei and Laxiflori are nested within sect. Astragalus; and (3) subsect. Chronopus constitutes a separate phylogenetic lineage. Representatives of sects. Astragalus, Alopecuroidei, and Laxiflori share a common ancestor with that of sect. Caprini. Our studies indicate that Astragalus annularis is an outlier species for the genus Astragalus and sect. Caraganella is the first-diverging clade within the genus Astragalus. Results of these analyses are supported by morphology and suggest the need for new taxonomic delimitations, which are forthcoming. Key morphological characters were mapped onto the phylogenetic tree and discussed.     

The effect of resistance level and stability demands on recruitment patterns and internal loading of spine in dynamic flexion and extension using a simple trunk model

The effects of external resistance on the recruitment of trunk muscles in sagittal movements and the coactivation mechanism to maintain spinal stability were investigated using a simple computational model of iso-resistive spine sagittal movements. Neural excitation of muscles was attained based on inverse dynamics approach along with a stability-based optimisation. The trunk flexion and extension movements between 60° flexion and the upright posture against various resistance levels were simulated. Incorporation of the stability constraint in the optimisation algorithm required higher antagonistic activities for all resistance levels mostly close to the upright position. Extension movements showed higher coactivation with higher resistance, whereas flexion movements demonstrated lower coactivation indicating a greater stability demand in backward extension movements against higher resistance at the neighbourhood of the upright posture. Optimal extension profiles based on minimum jerk, work and power had distinct kinematics profiles which led to recruitment patterns with different timing and amplitude of activation.     

Mitochondrial DNA sequence diversity in three ethnic populations from the South-west Iran: a preliminary study

To investigate the genetic structure of human populations in the South-west region of Iran, mitochondrial first hypervariable DNA sequences were obtained from 50 individuals representing three different ethnic groups from Khuzestan Province. Studied groups were Shushtari Persians and Chahar Lang Bakhtiyaries from Indo-European-speaking populations and Bani Torof Arabs from Semitic-speaking linguistic families. Genetic analysis of mtDNA data showed high similarity of Chahar Lang Bakhtiyaries with other Iranian Indo-European-speaking populations while Shushtaries and Bani Torofs had a closer affinity with Semitic-speaking groups rather than to other Iranian populations. The relationship of Chahar Lang Bakhtiyaries and Bani Torof Arabs with their neighbor populations can be explained by linguistic and geographic proximity. Whereas, the greater similarity of Shushtari Persians with West Asian Arabs is probably according to high gene flow between them. This article represents a preliminary study of three major ethnic groups of South-west Iran which investigates the potential genetic substructure of the region.     

Molecular phylogeny and taxonomy of <Emphasis Type="Italic">Tanacetum</Emphasis> L. (Compositae,Anthemideae) inferred from nrDNA ITS and cpDNA <Emphasis Type="Italic">trn</Emphasis>H–<Emphasis Type="Italic">psb</Emphasis>A sequence variation

The genus Tanacetum L. consists of around 160 species of the Compositae-Anthemideae. It holds a crucial position for understanding the phylogeny of the tribe and its subtribal and generic classification. The present study focuses on the phylogenetic relationships of the species and aims at a discussion of the infrageneric classification and boundaries of the genus. Sequence information from a nuclear [nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS)] and a chloroplast marker [chloroplast DNA (cpDNA) trnH–psbA] was used to infer the phylogeny of Tanacetum and many representatives of closely related genera. Bayesian inference methods were used for the phylogenetic reconstructions based on a combined dataset including both sequence and indel information. Contrasting the high morphological diversity in the genus, sequence divergence among Tanacetum representatives included was found to be very low, leading to unresolved phylogenetic relationships within the genus. Nevertheless, the generic separation of Tanacetum from other members of subtribe Anthemidinae (i.e., Anthemis, Archanthemis, Cota, Nananthea, and Tripleurospermum) emerges, while other, presently accepted genera are found nested in Tanacetum (i.e., Gonospermum, Lugoa, and Xylanthemum). Finally, the phylogenetic independence of the SW European T. microphyllum from the rest of Tanacetum and the other genera of Anthemidinae is found to receive strong support and is also backed by its morphological uniqueness. The new genus Vogtia Oberpr. et Sonboli is described to accommodate Tanacetum microphyllum and the closely related species T. annuum. The sinking of Gonospermum, Lugoa, and Xylanthemum into a broadly circumscribed genus Tanacetum is proposed until more stable phylogenetic reconstructions based on more and more variable molecular markers are possible. Concerning the infrageneric classification of Tanacetum, the phylogeny does not support the separation of the white- and red-rayed species (the former genus Pyrethrum) from the discoid, disciform, or yellow-rayed ones (i.e., Tanacetum in the strict sense) at any infrageneric rank. The hypothesis by Tzvelev (1961) that the yellow-rayed representatives may have evolved from disciform ancestors receives little support.     

The CD20 calcium channel is localized to microvilli and constitutively associated with membrane rafts: antibody binding increases the affinity of the association through an epitope-dependent cross-linking-independent mechanism

CD20 is a B cell-specific membrane protein that functions in store-operated calcium entry and serves as a useful target for antibody-mediated therapeutic depletion of B cells. Antibody binding to CD20 induces a diversity of biological effects, some of which are dependent on lipid rafts. Rafts are isolated as low density detergent-resistant membranes, initially characterized using Triton X-100. We have previously reported that CD20 is soluble in 1% Triton but that antibodies induce the association of CD20 with Triton-resistant rafts. However, by using several other detergents to isolate rafts and by microscopic co-localization with a glycosylphosphatidylinositol-linked protein, we show in this report that CD20 is constitutively raft-associated. CD20 was distributed in a punctate pattern on the cell surface as visualized by fluorescence imaging and was also localized to microvilli by electron microscopy. The mechanism underlying antibody-induced association of CD20 with Triton-resistant rafts was investigated and found not to require cellular ATP, kinase activity, actin polymerization, or antibody cross-linking but was dependent on the epitope recognized. Thus, antibody-induced insolubility in 1% Triton most likely reflects a transition from relatively weak to strong raft association that occurs as a result of a conformational change in the CD20 protein.     

Real-time in vivo imaging of platelets,tissue factor and fibrin during arterial thrombus formation in the mouse

We have used confocal and widefield microscopy to image thrombus formation in real time in the microcirculation of a living mouse. This system provides high-speed, near-simultaneous acquisition of images of multiple fluorescent probes and of a brightfield channel. Vascular injury is induced with a laser focused through the microscope optics. We observed platelet deposition, tissue factor accumulation and fibrin generation after laser-induced endothelial injury in a single developing thrombus. The initiation of blood coagulation in vivo entailed the initial accumulation of tissue factor on the upstream and thrombus-vessel wall interface of the developing thrombus. Subsequently tissue factor was associated with the interior of the thrombus. Tissue factor was biologically active, and was associated with fibrin generation within the thrombus.     

An experimental design framework for Markovian gene regulatory networks under stationary control policy

Background

A fundamental problem for translational genomics is to find optimal therapies based on gene regulatory intervention. Dynamic intervention involves a control policy that optimally reduces a cost function based on phenotype by externally altering the state of the network over time. When a gene regulatory network (GRN) model is fully known, the problem is addressed using classical dynamic programming based on the Markov chain associated with the network. When the network is uncertain, a Bayesian framework can be applied, where policy optimality is with respect to both the dynamical objective and the uncertainty, as characterized by a prior distribution. In the presence of uncertainty, it is of great practical interest to develop an experimental design strategy and thereby select experiments that optimally reduce a measure of uncertainty.

Results

In this paper, we employ mean objective cost of uncertainty (MOCU), which quantifies uncertainty based on the degree to which uncertainty degrades the operational objective, that being the cost owing to undesirable phenotypes. We assume that a number of conditional probabilities characterizing regulatory relationships among genes are unknown in the Markovian GRN. In sum, there is a prior distribution which can be updated to a posterior distribution by observing a regulatory trajectory, and an optimal control policy, known as an “intrinsically Bayesian robust” (IBR) policy. To obtain a better IBR policy, we select an experiment that minimizes the MOCU remaining after applying its output to the network. At this point, we can either stop and find the resulting IBR policy or proceed to determine more unknown conditional probabilities via regulatory observation and find the IBR policy from the resulting posterior distribution. For sequential experimental design this entire process is iterated. Owing to the computational complexity of experimental design, which requires computation of many potential IBR policies, we implement an approximate method utilizing mean first passage times (MFPTs) – but only in experimental design, the final policy being an IBR policy.

Conclusions

Comprehensive performance analysis based on extensive simulations on synthetic and real GRNs demonstrate the efficacy of the proposed method, including the accuracy and computational advantage of the approximate MFPT-based design.