The production of mature germ cells capable of generating totipotent zygotes is a highly specialized and sexually dimorphic process. The transition from diploid primordial germ cell to haploid spermatozoa requires genome-wide reprogramming of DNA methylation, stage-and testis-specific gene expression, mitotic and meiotic division, and the histone-protamine transition, all requiring unique epigenetic control. Dnmt3L, a DNA methyltransferase regulator, is expressed during gametogenesis, and its deletion results in sterility. We found that during spermatogenesis, Dnmt3L contributes to the acquisition of DNA methylation at paternally imprinted regions, unique nonpericentric heterochromatic sequences, and interspersed repeats, including autonomous transposable elements. We observed retrotransposition of an LTR-ERV1 element in the DNA from Dnmt3L ؊/؊ germ cells, presumably as a result of hypomethylation. Later in development, in Dnmt3L ؊/؊ meiotic spermatocytes, we detected abnormalities in the status of biochemical markers of heterochromatin, implying aberrant chromatin packaging. Coincidentally, homologous chromosomes fail to align and form synaptonemal complexes, spermatogenesis arrests, and spermatocytes are lost by apoptosis and sloughing. Because Dnmt3L expression is restricted to gonocytes, the presence of defects in later stages reveals a mechanism whereby early genome reprogramming is linked inextricably to changes in chromatin structure required for completion of spermatogenesis.epigenetics ͉ meiosis ͉ histone modification ͉ heterochromatin ͉ DNA methylation

Bacterial LPS triggers dramatic changes in gene expression in macrophages. We show here that LPS regulated several members of the histone deacetylase (HDAC) family at the mRNA level in murine bone marrow-derived macrophages (BMM). LPS transiently repressed, then induced a number of HDACs (Hdac-4, 5, 7) in BMM, whereas Hdac-1 mRNA was induced more rapidly. Treatment of BMM with trichostatin A (TSA), an inhibitor of HDACs, enhanced LPS-induced expression of the Cox-2, Cxcl2, and Ifit2 genes. In the case of Cox-2, this effect was also apparent at the promoter level. Overexpression of Hdac-8 in RAW264 murine macrophages blocked the ability of LPS to induce Cox-2 mRNA. Another class of LPS-inducible genes, which included Ccl2, Ccl7, and Edn1, was suppressed by TSA, an effect most likely mediated by PU.1 degradation. Hence, HDACs act as potent and selective negative regulators of proinflammatory gene expression and act to prevent excessive inflammatory responses in macrophages.

Medicinal plants are a reservoir of biologically active compounds with therapeutic properties that over time have been reported and used by diverse groups of people for treatment of various diseases. This review covers 15 selected medicinal plants distributed in Myanmar, including Dalbergia cultrata, Eriosema chinense, Erythrina suberosa, Millettia pendula, Sesbania grandiflora, Tadehagi triquetrum, Andrographis echioides, Barleria cristata, Justicia gendarussa, Premna integrifolia, Vitex trifolia, Acacia pennata, Cassia auriculata, Croton oblongifolius and Glycomis pentaphylla. Investigation of the phytochemical constituents, biological and pharmacological activities of the selected medicinal plants is reported. This study aims at providing a collection of publications on the species of selected medicinal plants in Myanmar along with a critical review of the literature data. As a country, Myanmar appears to be a source of traditional drugs that have not yet been scientifically investigated. This review will be support for further investigations on the pharmacological activity of medicinal plant species in Myanmar.

The genera Dracaena and Sansevieria (Asparagaceae, Nolinoideae) are still poorly resolved phylogenetically. Plants of these genera are commonly distributed in Africa, China, Southeast Asia, and America. Most of them are cultivated for ornamental and medicinal purposes and are used in various traditional medicines due to the wide range of ethnopharmacological properties. Extensive in vivo and in vitro tests have been carried out to prove the ethnopharmacological claims and other bioactivities. These investigations have been accompanied by the isolation and identification of hundreds of phytochemical constituents. The most characteristic metabolites are steroids, flavonoids, stilbenes, and saponins; many of them exhibit potent analgesic, anti-inflammatory, antimicrobial, antioxidant, antiproliferative, and cytotoxic activities. This review highlights the structures and bioactivities of flavonoids and stilbenoids isolated from Dracaena and Sansevieria.

Mushrooms have a long history of uses for their medicinal and nutritional properties. They have been consumed by people for thousands of years. Edible mushrooms are collected in the wild or cultivated worldwide. Recently, mushroom extracts and their secondary metabolites have acquired considerable attention due to their biological effects, which include antioxidant, antimicrobial, anti-cancer, anti-inflammatory, anti-obesity, and immunomodulatory activities. Thus, in addition to phytochemists, nutritionists and consumers are now deeply interested in the phytochemical constituents of mushrooms, which provide beneficial effects to humans in terms of health promotion and reduction of disease-related risks. In recent years, scientific reports on the nutritional, phytochemical and pharmacological properties of mushroom have been overwhelming. However, the bioactive compounds and biological properties of wild edible mushrooms growing in Southeast Asian countries have been rarely described. In this review, the bioactive compounds isolated from 25 selected wild edible mushrooms growing in Southeast Asia have been reviewed, together with their biological activities. Phytoconstituents with antioxidant and antimicrobial activities have been highlighted. Several evidences indicate that mushrooms are good sources for natural antioxidants and antimicrobial agents

A methanolic extract of Argusia (or Messerschmidia or Tournefortia) argentea (Boraginaceae) significantly inhibited hemorrhage induced by crude venom of Trimeresurus flavoviridis. The extract was then separated according to antivenom activity by using silica gel column chromatography and HPLC equipped with an octadecylsilanized silica gel (ODS) column to afford rosmarinic acid (RA) (1) as an active principle. RA (1) significantly inhibited the hemorrhagic effect of crude venoms of T. flavoviridis, Crotalus atrox, Gloydius blomhoffii, Bitis arietans as well as snake venom metalloproteinases, HT-b (C. atrox), bilitoxin 2 (Agkistrodon bilineatus), HF (B. arietans), and Ac1-proteinase (Deinagkistrodon acutus). This is the first report of the antihemorrhage activity of RA (1), and RA (1) greatly contributes to the antihemorrhagic efficiency of A. argentea against crude snake venoms and hemorrhagic toxins.

The species Dracaena and Sansevieria, that are well-known for different uses in traditional medicines and as indoor ornamental plants with air purifying property, are rich sources of bioactive secondary metabolites. In fact, a wide variety of phytochemical constituents have been isolated so far from about seventeen species. This paper has reviewed the literature of about 180 steroidal saponins, isolated from Dracaena and Sansevieria species, as a basis for further studies. Saponins are among the most characteristic metabolites isolated from the two genera. They show a great variety in structural motifs and a wide range of biological activities, including anti-inflammatory, anti-microbial, anti-proliferative effects and, in most case, remarkable cytotoxic properties.

No abstract