Identification and role of carbohydrates on the surface of gametes in the zebra mussel, Dreissena polymorpha.

The objective of this study is to identify surface carbohydrates on zebra mussel, Dreissena polymorpha, eggs and sperm and to analyze their potential role in fertilization. The lectins WGA, Con A, LcH, LTA, SBA, PNA, and GSII were tested for affinity to both eggs and sperm. WGA, Con A, and LcH uniformly labeled eggs.

Flow-cytometric analyses of viability biomarkers in pesticide-exposed sperm of three aquatic invertebrates.

Toxicity studies on sperm often use fertilization success as the end point. This type of assay can be affected by sperm density, egg quality, and sperm-egg compatibility. Testing sperm viability biomarkers with flow cytometry is a fast, high-throughput technique for seminal analysis.

Inhibition of DNA methyltransferase 1 expression in bovine fibroblast cells used for nuclear transfer.

The aberrant expression of DNA methyltransferase 1 (DNMT1) in cloned embryos has been implicated as a possible factor in the improper donor genome reprogramming during nuclear transfer. DNMT1 is responsible for maintaining DNA methylation and the subsequent differentiation status of somatic cells. The presence of DNMT1 transcript in the donor cell may contribute to perpetuation of the highly methylated status of the somatic nuclei in cloned embryos.

Effect of epigenetic modifications of donor somatic cells on the subsequent chromatin remodeling of cloned bovine embryos.

Evidence indicates that failure of nuclear transfer (NT) embryos to develop normally can be attributed, at least partially, to the use of differentiated cells as the donor karyoplast. Blastocyst production and development to term of cloned embryos has been hypothesized to differ between population doublings of the same cell line as a consequence of changes in the levels of DNA methyltransferase 1 (DNMT1) and methylated DNA during in vitro culture. The objective of this study was to determine embryo production, developmental potential, and gene expression patterns of prehatched and posthatched embryos generated using donor cells with different levels of DNMT1 transcript.

DNA methylation and histone acetylation patterns in cultured bovine fibroblasts for nuclear transfer.

Evidence indicates that failure of nuclear transfer (NT) embryos to develop normally can be attributed, at least partially, to the use of a differentiated cell nucleus as the donor karyoplast. It has been hypothesized that blastocyst production and development to term of cloned embryos may differ between population doublings (PDs) of the same cell line as a consequence of changes in DNA methylation and histone acetylation patterns during in vitro culture. The objective of this study was to determine gene expression patterns of the chromatin remodeling proteins DNA methyltransferase-1 (Dnmt1), methyl CpG binding protein-2 (MeCP2), and histone deacetyltransferse-1 (HDAC1), in addition, to measuring levels of DNA methylation and histone acetylation of bovine fibroblast cells at different PDs.

Proliferative characteristics and chromosomal stability of bovine donor cells for nuclear transfer.

Few studies have characterized donor cell lines in terms of proliferative capacity and chromosomal stability. Abnormal phosphorylation patterns of the histones during metaphase could lead to abnormal chromosome segregation and extensive chromosome loss during mitosis. Suboptimal culture conditions may lead to abnormal histone H3 phosphorylation patterns, ultimately inducing missegregation and loss of chromosomes.

Sperm incorporation and pronuclear development during fertilization in the freshwater bivalve Dreissena polymorpha.

The invasive zebra mussel, Dreissena polymorpha (D. polymorpha), is proving to be a valuable model for understanding general mechanisms of fertilization, particularly regarding sperm incorporation. In the present study, we tracked the various components of the fertilizing sperm of D.

PHYSIOLOGICAL AND BIOCHEMICAL INVESTIGATIONS OF THE EGG JELLY RELEASE IN PENAEUS AZTECUS.

Following contact with seawater, Penaeus aztecus ova undergo a massive release of extracortical jelly precursor material which is transformed into a layer of jelly-like material surrounding the ova. Release and dissipation of the precursors can be irreversibly inhibited by the protease inhibitors N-a-p-tosyl-L-lysine chloromethyl ketone and soybean trypsin inhibitor, implicating trypsin-like proteases in the process. Treatment with the less-specific enzyme inhibitor phenylmethyl sulfonyl fluoride also irreversibly inhibits the release of the cortical material.