Osmoconditioning reduces physiological and biochemical damage induced by chilling in soybean seeds

The aim of the present work was to investigate the effects of osmoconditioning on chilling injury in soybean (Glycine max (L.) Merr.) seeds during imbibition. Soybean seeds germinated readily over a large range of temperatures (10-35 degrees C), the thermal optimum being 25-30 degrees C. Low temperatures reduced the germination rate and no seed germinated at 1 degrees C. Pre-treatment of seeds at 1 degrees C reduced further germination at the optimal temperature (25 degrees C). This deleterious effect of chilling increased with duration of the treatment, and was maximal after 4 days. Osmoconditioning of seeds at 20 degrees C with a polyethylene glycol-8000 solution at -1.5 MPa for at least 24 h followed by drying back the seeds to their initial moisture content reduced their chilling sensitivity and even allowed germination at 1 degrees C. Chilling of control seeds resulted in a sharp decline in in vivo ACC-dependent ethylene production and in an increase in electrolyte leakage in the medium, which indicated deterioration of membrane properties. Osmoconditioned seeds placed at 1 degrees C did not show any reduction in their ability to convert ACC to ethylene nor any strong increase in electrolyte leakage. Imbibition of both control and osmoconditioned seeds at 1 degrees C resulted in a marked increase in ATP level (more than 50% of the total nucleotides) and energy charge; however, the latter cannot be considered as an indicator of chilling since it remained high (0.74-0.88) throughout the cold treatment. Chilling treatment longer than 6 days induced accumulation of malondialdehyde in the embryonic axis, which was more marked in control seeds than in osmoconditioned seeds, suggesting that chilling sensitivity was associated with lipid peroxidation. Imbibition of seeds at 1 degrees C resulted in an increase in superoxide dismutase, catalase and glutathione reductase activity, which was generally higher in osmoconditioned seeds than in control ones. This stimulation of the antioxidant defence systems occurred during the 4 first days of chilling and decreased then in control seeds while it remained high in osmoconditioned ones. Re-warming seeds at 25 degrees C resulted in an increase in all enzyme activity involved in antioxidant defence. However this effect of re-warming decreased in control seeds after 4 days of chilling, whereas it was maintained in osmoconditioned seeds.     

Current medical treatment of estrogen receptor-positive breast cancer

Approximately 80% of breast cancers(BC) are estrogen receptor(ER)-positive and thus endocrine therapy(ET) should be considered complementary to surgery in the majority of patients. The advantages of oophorectomy, adrenalectomy and hypophysectomy in women with advanced BC have been demonstrated many years ago, and currently ET consist of(1) ovarian function suppression(OFS), usually obtained using gonadotropinreleasing hormone agonists(Gn RHa);(2) selective estrogen receptor modulators or down-regulators(SERMs or SERDs); and(3) aromatase inhibitors(AIs), or a combination of two or more drugs. For patients aged less than 50 years and ER+ BC, there is no conclusive evidence that the combination of OFS and SERMs(i.e., tamoxifen) or chemotherapy is superior to OFS alone. Tamoxifen users exhibit a reduced risk of BC, both invasive and in situ, especially during the first 5 years of therapy, and extending the treatment to 10 years further reduced the risk of recurrences. SERDs(i.e., fulvestrant) are especially useful in the neoadjuvant treatment of advanced BC, alone or in combination with either cytotoxic agents or AIs. There are two types of AIs: type Ⅰ are permanent steroidal inhibitors of aromatase, while type Ⅱ are reversible nonsteroidal inhibitors. Several studies demonstrated the superiority of the third-generation AIs(i.e., anastrozole and letrozole) compared with tamoxifen, and adjuvant therapy with AIs reduces the recurrence risk especially in patients with advanced BC. Unfortunately, some cancers are or became ET-resistant, and thus other drugs have been suggested in combination with SERMs or AIs, including cyclin-dependent kinase 4/6 inhibitors(palbociclib) and mammalian target of rapamycin(m TOR) inhibitors, such as everolimus. Further studies are required to confirm their real usefulness.     

Decreased CD8<Superscript>+</Superscript>T cell response to Epstein-Barr virus infected B cells in multiple sclerosis is not due to decreased HLA class I expression on B cells or monocytes

Background  

Patients with multiple sclerosis (MS) have a decreased frequency of CD8⁺ T cells reactive to their own Epstein-Barr virus (EBV) infected B cells. We have proposed that this might predispose to the development of MS by allowing EBV-infected autoreactive B cells to accumulate in the central nervous system. The decreased CD8⁺ T cell response to EBV results from a general CD8⁺ T cell deficiency and also a decreased proportion of EBV-specific T cells within the total CD8⁺ T cell population. Because decreased HLA class I expression on monocytes and B cells has been reported in MS and could influence the generation and effector function of EBV-specific CD8⁺ T cells, the present study was undertaken to measure the expression of HLA molecules on B cells and monocytes in patients with MS.     

<Emphasis Type="Italic">Escherichia coli</Emphasis> phylogenetic group determination and its application in the identification of the major animal source of fecal contamination

Background  

Escherichia coli strains are commonly found in the gut microflora of warm-blooded animals. These strains can be assigned to one of the four main phylogenetic groups, A, B1, B2 and D, which can be divided into seven subgroups (A₀, A₁, B1, B2₂, B2₃, D₁ and D₂), according to the combination of the three genetic markers chuA, yjaA and DNA fragment TspE4.C2. Distinct studies have demonstrated that these phylo-groups differ in the presence of virulence factors, ecological niches and life-history. Therefore, the aim of this work was to analyze the distribution of these E. coli phylo-groups in 94 human strains, 13 chicken strains, 50 cow strains, 16 goat strains, 39 pig strains and 29 sheep strains and to verify the potential of this analysis to investigate the source of fecal contamination.     

Activity of some Nile River aquatic macrophyte extracts against the cyanobacterium Microcystis aeruginosa

The anti-algal activity of five macrophyte extracts on the cyanobacterium Microcystis aeruginosa in Egypt was investigated in 2013. Extract activity varied according to plant type, extracting solvent and its concentration. The highest inhibitory activity was achieved with ethanol extract at a concentration of 80 mg l^?1, followed by chloroformic extracts, at 60 mg l^?1. Methanolic extracts of Eichhornia crassipes and Polygonum tomentosum inhibited growth of Microcystis aeruginosa at all concentrations. Acetonic extracts inhibited algal growth at 60 mg l^?1, except for the extract of Ceratophyllum subdemersum, which showed stimulation of M. aeruginosa growth. Eichhornia crassipes ethanolic extract exerted the most powerful inhibition by more than five-fold, 570.17%, followed by those of P. tomentosum, Saccharum spontaneum, Ceratophyllum demersum and C. subdemersum, 559.48, 553.99, 544.11 and 366.51%, respectively. Phytochemical screening for the tested plant extracts revealed the presence of biologically active substances of different concentrations, with P. tomentosum having the highest polyphenols, 1.95% of dry weight.     

Quantitation of junctional and extrajunctional acetylcholine receptors by electron microscope autoradiography after (125)I-α-bungarotoxin binding at mouse neuromuscular junctions

The distribution and quantitation of 125I-alpha-bungarotoxin (alpha-BTX) binding sites and thus acetylcholine receptor (AChR) were determined in mouse sternomastoid muscle by electron microscope autoradiography. We found that a valid criterion for receptor saturation at the neuromuscular junction was the complete elimination of neurally evoked tetanic muscle contractions, since, when such a criterion was used for the endpoint of toxin incubation, alpha-BTX was bound to approximately 90% of total available endplate sites. When, without implying localization, the presynaptic axonal membrane was used as a convenient reference structure, the concentration of alpha-BTX relative to this membrane was determined to be 46,000 +/- 27% sites/mum2.     

T-cell activation without proliferation in juvenile idiopathic arthritis

A study was done to determine if the differentiation and activation phenotype of T cells in synovial fluid (SF) from patients with juvenile idiopathic arthritis (JIA) is associated with T-cell proliferation in situ. Mononuclear cells were isolated from 44 paired samples of peripheral blood and SF. Differentiation and activation markers were determined on CD4 and CD8 T cells by flow cytometry. Cell-cycle analysis was performed by propidium iodide staining, and surface-marker expression was also assessed after culture of the T cells under conditions similar to those found in the synovial compartment. The majority of the T cells in the SF were CD45RO⁺CD45RB^dull. There was greater expression of the activation markers CD69, HLA-DR, CD25 and CD71 on T cells from SF than on those from peripheral blood. Actively dividing cells accounted for less than 1% of the total T-cell population in SF. The presence or absence of IL-16 in T-cell cultures with SF or in a hypoxic environment did not affect the expression of markers of T-cell activation. T cells from the SF of patients with JIA were highly differentiated and expressed early and late markers of activation with little evidence of in situ proliferation. This observation refines and extends previous reports of the SF T-cell phenotype in JIA and may have important implications for our understanding of chronic inflammation.     

Blood shizonticidal activities of phenazines and naphthoquinoidal compounds against Plasmodium falciparum in vitro and in mice malaria studies

Due to the recent advances of atovaquone, a naphthoquinone, through clinical trials as treatment for malarial infection, 19 quinone derivatives with previously reported structures were also evaluated for blood schizonticide activity against the malaria parasite Plasmodium falciparum. These compounds include 2-hydroxy-3-methylamino naphthoquinones (2-9), lapachol (10), nor-lapachol (11), iso-lapachol (12), phthiocol (13) and phenazines (12-20). Their cytotoxicities were also evaluated against human hepatoma and normal monkey kidney cell lines. Compounds 2 and 5 showed the highest activity against P. falciparum chloroquine-resistant blood-stage parasites (clone W2), indicated by their low inhibitory concentration for 50% (IC₅₀) of parasite growth. The therapeutic potential of the active compounds was evaluated according to the selectivity index, which is a ratio of the cytotoxicity minimum lethal dose which eliminates 50% of cells and the in vitro IC₅₀. Naphthoquinones 2 and 5, with activities similar to the reference antimalarial chloroquine, were also active against malaria in mice and suppressed parasitaemia by more than 60% in contrast to compound 11 which was inactive. Based on their in vitro and in vivo activities, compounds 2 and 5 are considered promising molecules for antimalarial treatment and warrant further study.