Mouse Fibroblast L929 Cell Line as a Useful Tool for Replication and Adaptation of Infectious Bursal Disease Virus

Infectious bursal disease virus (IBDV) causes a highly contagious disease associated with immunosuppression in young chickens. Production of either egg-based or primary cell-based high-quality vaccines requires time-consuming and costly procedures. To determine a suitable cell line for IBDV replication, L929 cell line was a candidate for the growth kinetics processing of the virus. The L929 cells were proliferated in monolayer, and doubling time was calculated. Replication kinetics an IBDV isolate at the multiplicity of infection 0.1 PFU/cell were determined using virus titration. To adapt IBDV on L929 cells, seven consecutive passages were performed. Virus titer and levels of apoptosis were quantitatively analyzed at each passage. The viral VP2 gene was amplified and sequenced in three passages. An average doubling time of 21 h was estimated for monolayers of L929 cells. Although during early passages, virus growth did not produce a clear cytopathic effect (CPE), an increase in IBDV titers was observed. Serial passages led to the evidence of marked CPEs and an increase in the virus titer in the third passage. During the fourth to seventh passages, consistent CPEs characterized by the formation of granulated and round cells were evident within 24 to 48 hours post-inoculation. The titer of the virus was increased in the third passage onwards to peak in the fourth and constant at 5.9 TCID50 until the end passage. The IBDV replication in connection with DNA fragmentation and FITC, revealed the characteristic picture of apoptosis in a time-dependent manner. We found that the IBDV could easily be adapted to L929 cells, increasing virus yields by about two orders of magnitude. These results indicated that the cell line may be useful in the production of efficient virus particles.

Structural and functional analyses explain Pea KAI2 receptor diversity and reveal stereoselective catalysis during signal perception

KAI2 proteins are plant α/β hydrolase receptors which perceive smoke-derived butenolide signals and endogenous, yet unidentified KAI2-ligands (KLs). The number of functional KAI2 receptors varies among species and KAI2 gene duplication and sub-functionalization likely plays an adaptative role by altering specificity towards different KLs. Legumes represent one of the largest families of flowering plants and contain many agronomic crops. Prior to their diversification, KAI2 underwent duplication resulting in KAI2A and KAI2B. Here we demonstrate that Pisum sativum KAI2A and KAI2B are active receptors and enzymes with divergent ligand stereoselectivity. KAI2B has a higher affinity for and hydrolyses a broader range of substrates including strigolactone-like stereoisomers. We determine the crystal structures of PsKAI2B in apo and butenolide-bound states. The biochemical, structural, and mass spectra analyses of KAI2s reveal a transient intermediate on the catalytic serine and a stable adduct on the catalytic histidine, confirming its role as a bona fide enzyme. Our work uncovers the stereoselectivity of ligand perception and catalysis by diverged KAI2 receptors and proposes adaptive sensitivity to KAR/KL and strigolactones by KAI2B.

MAX2-independent transcriptional responses to rac-GR24 in Lotus japonicus roots

Strigolactones (SLs) and smoke-derived Karrikins (KARs) are structurally similar butenolide compounds that control distinct aspects of plant development. They are perceived by two closely related α/β hydrolases D14 and KAI2, respectively. Responses to both molecules involve the F-box protein MAX2 that participates in the Skp1-Cullin-F-box (SCF) complex, which ubiquitylates developmental regulators of the SMXL family to mark them for degradation by the 26S proteasome, enabling SL and KAR responses. Current research on SL and KAR signaling uses the synthetic molecules rac-GR24, KAR₁ and KAR₂ for pharmacological treatments. In a previous microarray analysis, we observed transcriptional activation in response to rac-GR24 in Lotus japonicus seedling roots. We retested transcript accumulation of selected genes by quantitative PCR in the wild type and the max2-4 mutant, and found that surprisingly, a number of them respond to rac-GR24 in a MAX2-independent manner, and also respond in roots of d14 and kai2a kai2b double mutants. Thus, the synthetic compounds induce transcriptional responses independent of their perception by the canonical receptor complex.

Controlled Assays for Phenotyping the Effects of Strigolactone-Like Molecules on Arbuscular Mycorrhiza Development

Arbuscular mycorrhiza is an ancient symbiosis between most land plants and fungi of the Glomeromycotina, in which the fungi provide mineral nutrients to the plant in exchange for photosynthetically fixed organic carbon. Strigolactones are important signals promoting this symbiosis, as they are exuded by plant roots into the rhizosphere to stimulate activity of the fungi. In addition, the plant karrikin signaling pathway is required for root colonization. Understanding the molecular mechanisms underpinning root colonization by AM fungi, requires the use of plant mutants as well as treatments with different environmental conditions or signaling compounds in standardized cocultivation systems to allow for reproducible root colonization phenotypes. Here we describe how we set up and quantify arbuscular mycorrhiza in the model plants Lotus japonicus and Brachypodium distachyon under controlled conditions. We illustrate a setup for open pot culture as well as for closed plant tissue culture (PTC) containers, for plant-fungal cocultivation in sterile conditions. Furthermore, we explain how to harvest, store, stain, and image AM roots for phenotyping and quantification of different AM structures.

Lotus japonicus karrikin receptors display divergent ligand-binding specificities and organ-dependent redundancy

Karrikins (KARs), smoke-derived butenolides, are perceived by the α/β-fold hydrolase KARRIKIN INSENSITIVE2 (KAI2) and thought to mimic endogenous, yet elusive plant hormones tentatively called KAI2-ligands (KLs). The sensitivity to different karrikin types as well as the number of KAI2 paralogs varies among plant species, suggesting diversification and co-evolution of ligand-receptor relationships. We found that the genomes of legumes, comprising a number of important crops with protein-rich, nutritious seed, contain two or more KAI2 copies. We uncover sub-functionalization of the two KAI2 versions in the model legume Lotus japonicus and demonstrate differences in their ability to bind the synthetic ligand GR24ent-5DS in vitro and in genetic assays with Lotus japonicus and the heterologous Arabidopsis thaliana background. These differences can be explained by the exchange of a widely conserved phenylalanine in the binding pocket of KAI2a with a tryptophan in KAI2b, which arose independently in KAI2 proteins of several unrelated angiosperms. Furthermore, two polymorphic residues in the binding pocket are conserved across a number of legumes and may contribute to ligand binding preferences. The diversification of KAI2 binding pockets suggests the occurrence of several different KLs acting in non-fire following plants, or an escape from possible antagonistic exogenous molecules. Unexpectedly, L. japonicus responds to diverse synthetic KAI2-ligands in an organ-specific manner. Hypocotyl growth responds to KAR1, KAR2 and rac-GR24, while root system development responds only to KAR1. This differential responsiveness cannot be explained by receptor-ligand preferences alone, because LjKAI2a is sufficient for karrikin responses in the hypocotyl, while LjKAI2a and LjKAI2b operate redundantly in roots. Instead, it likely reflects differences between plant organs in their ability to transport or metabolise the synthetic KLs. Our findings provide new insights into the evolution and diversity of butenolide ligand-receptor relationships, and open novel research avenues into their ecological significance and the mechanisms controlling developmental responses to divergent KLs.

Molecular modelling of the antiviral action of Resveratrol derivatives against the activity of two novel SARS CoV-2 and 2019-nCoV receptors

The pandemic threat of COVID-19 causes serious concern for people and world organizations. The effect of Coronavirus disease on the lifestyle and economic status of humans is undeniable, and all of the researchers (biologists, pharmacists, physicians, and chemists) can help decrease its destructive effects. The molecular docking approach can provide a fast prediction of the positive influence the targets on the COVID-19 outbreak. In this work, we choose resveratrol (RV) derivatives (22 cases) and two newly released coordinate structures for COVID-19 as receptors [Papain-like Protease of SARS CoV-2 (PBD ID: 6W9C) and 2019-nCoV RNA-dependent RNA Polymerase (PBD ID: 6M71)]. The results show that conformational isomerism is significant and useful parameter for docking results. A wide spectrum of interactions such as Van der Waals, conventional hydrogen bond, Pi-donor hydrogen bond, Pi-Cation, Pi-sigma, Pi-Pi stacked, Amide-Pi stacked and Pi-Alkyl is detected via docking of RV derivatives and COVID-19 receptors. The potential inhibition effect of RV-13 (-184.99 kj/mol), and RV-12 (-173.76 kj/mol) is achieved at maximum value for 6W9C and 6M71, respectively.

A Flexible, Low-Cost Hydroponic Co-Cultivation System for Studying Arbuscular Mycorrhiza Symbiosis

Arbuscular mycorrhiza (AM) is a widespread symbiosis between plant roots and fungi of the Glomeromycotina, which improves nutrient uptake by plants. The molecular mechanisms underlying development and function of the symbiosis are subject to increasing research activity. Since AM occurs in the soil, most studies targeting a molecular understanding of AM development and function, use solid substrates for co-cultivating plants and AM fungi. However, for some experiments very clean roots, highly controlled nutrient conditions or applications of defined concentrations of signaling molecules (such as hormones) or other small chemicals (such as synthetic inhibitors or signaling agonists) are needed. To this end, hydroponics has been widely used in research on mechanisms of plant nutrition and some hydroponic systems were developed for AM fungal spore amplification. Here, we present a hydroponics set-up, which can be successfully utilized for experimental root colonization assays. We established a "tip-wick" system based on pipette tips and rock wool wicks for co-cultivation of AM fungi with small model plants such as Lotus japonicus. A larger "Falcon-wick" system using Falcon tubes and rockwool wicks was developed for larger model plants such as rice. The hydroponic system can also be employed for growing L. japonicus hairy roots after transformation by Agrobacterium rhizogenes, thus circumventing the laborious cultivation on agar medium-containing Petri dishes during hairy root development. The tip-wick and Falcon-wick systems are easy to use and can be built with low cost, conventional and reusable lab plastic ware and a simple aquarium pump.

The impact of p16 and HER2 expression on survival in patients with ovarian carcinoma

The purpose of this study was to investigate the impact of p16 and HER2 expression on survival in patients with ovarian carcinoma.This descriptive-analytic, cross-sectional study, was conducted on 47 paraffin blocks of epithelial ovarian tumors. Suitable slides were prepared to evaluate HER2 and p16 by immunohistochemistry using HercepTest kit (DAKO) and p16INK4A kit (DAKO, code 5334). Clinical information and pathology data were extracted from patients' medical and pathology records. Data entry and analysis was done by SPSS (version 16) software. Chi-square test, Mann-Whitney test, t-test, Kruskal-Wallis test, log rank test and Kaplan-Meier method were used. The mean age of the patients was 51.6 years (range 19-71 years). The most common histological type of epithelial ovarian cancer was serous adenocarcinoma (68.1%). P16 expression was detected in 34% of epithelial ovarian tumors. P16 expression was significantly associated with stage of disease (P = 0.04) and overall survival (P = 0.001), but HER2 expression was not associated with overall survival, stage of disease and tumor histological type.Expression of p16 may be used as a prognostic factor of overall survival and stage of disease, while HER2 expression may not be used as a prognostic factor of overall survival.

The Low Molecular Weight Protein PsaI Stabilizes the Light-Harvesting Complex II Docking Site of Photosystem I

PsaI represents one of three low molecular weight peptides of PSI. Targeted inactivation of the plastid PsaI gene in Nicotiana tabacum has no measurable effect on photosynthetic electron transport around PSI or on accumulation of proteins involved in photosynthesis. Instead, the lack of PsaI destabilizes the association of PsaL and PsaH to PSI, both forming the light-harvesting complex (LHC)II docking site of PSI. These alterations at the LHCII binding site surprisingly did not prevent state transition but led to an increased incidence of PSI-LHCII complexes, coinciding with an elevated phosphorylation level of the LHCII under normal growth light conditions. Remarkably, LHCII was rapidly phosphorylated in ΔpsaI in darkness even after illumination with far-red light. We found that this dark phosphorylation also occurs in previously described mutants impaired in PSI function or state transition. A prompt shift of the plastoquinone (PQ) pool into a more reduced redox state in the dark caused an enhanced LHCII phosphorylation in ΔpsaI Since the redox status of the PQ pool is functionally connected to a series of physiological, biochemical, and gene expression reactions, we propose that the shift of mutant plants into state 2 in darkness represents a compensatory and/or protective metabolic mechanism. This involves an increased reduction and/or reduced oxidation of the PQ pool, presumably to sustain a balanced excitation of both photosystems upon the onset of light.

HIGH CHLOROPHYLL FLUORESCENCE145 Binds to and Stabilizes the psaA 5' UTR via a Newly Defined Repeat Motif in Embryophyta

The seedling-lethal Arabidopsis thaliana high chlorophyll fluorescence145 (hcf145) mutation leads to reduced stability of the plastid tricistronic psaA-psaB-rps14 mRNA and photosystem I (PSI) deficiency. Here, we genetically mapped the HCF145 gene, which encodes a plant-specific, chloroplast-localized, modular protein containing two homologous domains related to the polyketide cyclase family comprising 37 annotated Arabidopsis proteins of unknown function. Two further highly conserved and previously uncharacterized tandem repeat motifs at the C terminus, herein designated the transcript binding motif repeat (TMR) domains, confer sequence-specific RNA binding capability to HCF145. Homologous TMR motifs are often found as multiple repeats in quite diverse proteins of green and red algae and in the cyanobacterium Microcoleus sp PCC 7113 with unknown function. HCF145 represents the only TMR protein found in vascular plants. Detailed analysis of hcf145 mutants in Arabidopsis and Physcomitrella patens as well as in vivo and in vitro RNA binding assays indicate that HCF145 has been recruited in embryophyta for the stabilization of the psaA-psaB-rps14 mRNA via specific binding to its 5' untranslated region. The polyketide cyclase-related motifs support association of the TMRs to the psaA RNA, presumably pointing to a regulatory role in adjusting PSI levels according to the requirements of the plant cell.

Pro-oxidative toxicity of cells in suspension does not point to a cell cultural artefact as an explanation of the increased susceptibility of alveolar epithelial-like cells after glucocorticoid pretreatment

The influence of cell numbers on peroxide-(tertiary butylhydroperoxide (tBHP) or hydrogen peroxide-(HP)) or zinc-(zinc chloride) induced oxidative stress was assessed in alveolar epithelial-like cell lines in this work. Differences in cell numbers change the cellular glutathione and glutathione reductase activity as well as the amount of exported glutathione and therefore might influence susceptibility against oxidative stress. Toxicity due to zinc decreased, toxicity due to HP increased, while tBHP-mediated toxicity was unchanged in our experiments when cells were exposed in suspension as compared to monolayers. Toxicity of HP correlated to the glutathione content in monolayers and in cell suspensions, while zinc- or tBHP-mediated toxicity did not correlate towards glutathione. Decreasing cellular glutathione and the activity of some antioxidative enzymes by glucocorticoid pretreatment had no effect on toxicity of zinc or tBHP in L2 cells in suspensions, while toxicity in monolayers was increased. Glucocorticoid pretreatment seems to increase toxicity of HP in A549 monolayers according to the lowered protein content, while toxicity might be changed by a different way when cells are incubated as cell suspensions. No explanation as a cell culture artificial effect was observed, therefore we assume the increased toxicity after glucocorticoid pretreatment occurs in vivo as well.

PsbN is required for assembly of the photosystem II reaction center in Nicotiana tabacum

The chloroplast-encoded low molecular weight protein PsbN is annotated as a photosystem II (PSII) subunit. To elucidate the localization and function of PsbN, encoded on the opposite strand to the psbB gene cluster, we raised antibodies and inserted a resistance cassette into PsbN in both directions. Both homoplastomic tobacco (Nicotiana tabacum) mutants psbN-F and psbN-R show essentially the same PSII deficiencies. The mutants are extremely light sensitive and failed to recover from photoinhibition. Although synthesis of PSII proteins was not altered significantly, both mutants accumulated only ∼25% of PSII proteins compared with the wild type. Assembly of PSII precomplexes occurred at normal rates, but heterodimeric PSII reaction centers (RCs) and higher order PSII assemblies were not formed efficiently in the mutants. The psbN-R mutant was complemented by allotopic expression of the PsbN gene fused to the sequence of a chloroplast transit peptide in the nuclear genome. PsbN represents a bitopic trans-membrane peptide localized in stroma lamellae with its highly conserved C terminus exposed to the stroma. Significant amounts of PsbN were already present in dark-grown seedling. Our data prove that PsbN is not a constituent subunit of PSII but is required for repair from photoinhibition and efficient assembly of the PSII RC.

Recruitment of a ribosomal release factor for light- and stress-dependent regulation of petB transcript stability in Arabidopsis chloroplasts

Land plant genomes encode four functional ribosomal peptide chain release factors (Prf) of eubacterial origin, two (PrfA and PrfB homologs) for each endosymbiotic organelle. Formerly, we have shown that the Arabidopsis thaliana chloroplast-localized PrfB homolog, PrfB1, is required not only for termination of translation but also for stabilization of UGA stop codon-containing chloroplast transcripts. A previously undiscovered PrfB-like protein, PrfB3, is localized to the chloroplast stroma in a petB RNA-containing complex and found only in vascular plants. Highly conserved positions of introns unequivocally indicate that PrfB3 arose from a duplication of PrfB1. Notably, PrfB3 is lacking the two most important tripeptide motifs characteristic for all eubacterial and organellar PrfB homologs described so far: the stop codon recognition motif SPF and the catalytic center GGQ for peptidyl-tRNA hydrolysis. Complementation studies, as well as functional and molecular analyses of two allelic mutations in Arabidopsis, both of which lead to a specific deficiency of the cytochrome b₆f complex, revealed that PrfB3 is essentially required for photoautotrophic growth. Plastid transcript, polysome, and translation analyses indicate that PrfB3 has been recruited in vascular plants for light- and stress-dependent regulation of stability of 3' processed petB transcripts to adjust cytochrome b₆ levels.

Effect of acupuncture as a complementary medicine in treating insomnia

Introduction

Acupuncture, as complementary medicine, has been used since many years ago in china and many researches have proved its effect separately or combined with other treatment methods.

Objectives

To compare therapeutic effects of Acupuncture plus estazolam and Cognitive - Behavioral Therapy plus estazolam on insomnia.

Aims

To determine the efficacy of acupuncture as complementary medicine in treating insomnia.

Method

64 insomnia patients were randomly divided into an acupuncture group and a behavioral group, 30 cases in acupuncture group and 18 cases in behavioral group completed research. The acupuncture group was treated by administration oral estazolam before sleeping each day and needling, three times a week, the behavioral group received Stimulus control as a Cognitive - Behavioral Therapy plus oral estazolam before sleeping each day. Treatment course was 3 weeks. The insomnia severity index (ISI) scores before and after treatment were observed in the both groups.

Results

The total effective rate was 86.7% in the acupuncture group and 50% in the behavioral group with statistically significant difference (P < 0.05). The cured rate of 30% in the acupuncture group was significantly higher than 16.7% in the behavioral group (both P < 0.05).

Conclusions

The therapeutic effect of Acupuncture as a complementary medicine on insomnia is better than stimulus therapy as a Cognitive - Behavioral Therapy.

Kala azar with disseminated dermal leishmaniasis

In this report we summarize 5 cases of kala azar with disseminated dermal leishmaniasis. All had fever, hepatosplenomegaly, and disseminated skin lesions on admission. Maculopapular, pustular, and maculonodular eruptions were present, located mainly on the face and extremities. Innumerable amastigotes were demonstrated in the bone marrow and in the skin biopsies. All patients responded to Glucantime therapy.