Toward invasive mussel genetic biocontrol: Approaches, challenges, and perspectives.

Invasive freshwater mussels, such as the zebra (), quagga (), and golden () mussel have spread outside their native ranges throughout many regions of the North American, South American, and European continents in recent decades, damaging infrastructure and the environment. This review describes ongoing efforts by multiple groups to develop genetic biocontrol methods for invasive mussels. First, we provide an overview of genetic biocontrol strategies that have been applied in other invasive or pest species.

A 13-plex of tetra- and penta-STRs to identify zebrafish.

The zebrafish species Danio rerio has become one of the major vertebrate model organisms used in biomedical research. However, there are aspects of the model that need to be improved. One of these is the ability to identify individual fish and fish lines by DNA profiling.

Size-Dependent Toxicity of Gold Nanoparticles on Human Embryonic Stem Cells and Their Neural Derivatives.

This study explores the use of human embryonic stem cells (hESCs) for assessing nanotoxicology, specifically, the effect of gold nanoparticles (AuNPs) of different core sizes (1.5, 4, and 14 nm) on the viability, pluripotency, neuronal differentiation, and DNA methylation of hESCs. The hESCs exposed to 1.

Multigenerational epigenetic inheritance in humans: DNA methylation changes associated with maternal exposure to lead can be transmitted to the grandchildren.

We report that the DNA methylation profile of a child's neonatal whole blood can be significantly influenced by his or her mother's neonatal blood lead levels (BLL). We recruited 35 mother-infant pairs in Detroit and measured the whole blood lead (Pb) levels and DNA methylation levels at over 450,000 loci from current blood and neonatal blood from both the mother and the child. We found that mothers with high neonatal BLL correlate with altered DNA methylation at 564 loci in their children's neonatal blood.

Early life lead exposure causes gender-specific changes in the DNA methylation profile of DNA extracted from dried blood spots.

Aims: In this paper, we tested the hypothesis that early life lead (Pb) exposure associated DNA methylation (5 mC) changes are dependent on the sex of the child and can serve as biomarkers for Pb exposure.

Methods: In this pilot study, we measured the 5mC profiles of DNA extracted from dried blood spots (DBS) in a cohort of 43 children (25 males and 18 females; ages from 3 months to 5 years) from Detroit. Result & Discussion: We found that the effect of Pb-exposure on the 5-mC profiles can be separated into three subtypes: affected methylation loci which are conserved irrespective of the sex of the child (conserved); affected methylation loci unique to males (male-specific); and affected methylation loci unique to females (female-specific).

Lead exposure induces changes in 5-hydroxymethylcytosine clusters in CpG islands in human embryonic stem cells and umbilical cord blood.

Prenatal exposure to neurotoxicants such as lead (Pb) may cause stable changes in the DNA methylation (5mC) profile of the fetal genome. However, few studies have examined its effect on the DNA de-methylation pathway, specifically the dynamic changes of the 5-hydroxymethylcytosine (5hmC) profile. Therefore, in this study, we investigate the relationship between Pb exposure and 5mC and 5hmC modifications during early development.

Epigenetics as an answer to Darwin's "special difficulty," Part 2: natural selection of metastable epialleles in honeybee castes.

In a recent perspective in this journal, Herb (2014) discussed how epigenetics is a possible mechanism to circumvent Charles Darwin's "special difficulty" in using natural selection to explain the existence of the sterile-fertile dimorphism in eusocial insects. Darwin's classic book "On the Origin of Species by Means of Natural Selection" explains how natural selection of the fittest individuals in a population can allow a species to adapt to a novel or changing environment. However, in bees and other eusocial insects, such as ants and termites, there exist two or more castes of genetically similar females, from fertile queens to multiple sub-castes of sterile workers, with vastly different phenotypes, lifespans, and behaviors.

Lead exposure disrupts global DNA methylation in human embryonic stem cells and alters their neuronal differentiation.

Exposure to lead (Pb) during childhood can result in learning disabilities and behavioral problems. Although described in animal models, whether Pb exposure also alters neuronal differentiation in the developing brains of exposed children is unknown. Here, we investigated the effects of physiologically relevant concentrations of Pb (from 0.

Epigenetics of early-life lead exposure and effects on brain development.

The epigenetic machinery plays a pivotal role in the control of many of the body's key cellular functions. It modulates an array of pliable mechanisms that are readily and durably modified by intracellular or extracellular factors. In the fast-moving field of neuroepigenetics, it is emerging that faulty epigenetic gene regulation can have dramatic consequences on the developing CNS that can last a lifetime and perhaps even affect future generations.

Hypothesis: environmental regulation of 5-hydroxymethylcytosine by oxidative stress.

Many environmental toxins, such as heavy metals, air particles, and ozone, induce oxidative stress and decrease the levels of NADH and NADPH, cofactors that drive anabolic biochemical reactions and provide reducing capacity to combat oxidative stress. Recently, it was found that the Ten-eleven translocation (TET) protein family members, which oxidize 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC) in the DNA, is activated under high oxygen conditions by alpha ketoglutarate (α-KG), a cofactor produced by aerobic metabolism in the citric acid cycle. TET, Jumonji-family histone demethylases, and prolyl hydroxylase, a repressor of HIF1α under high oxygen conditions, all require alpha ketoglutarate (α-KG) as cofactors for their activation.

Distribution of carnosine-like peptides in the nervous system of developing and adult zebrafish (Danio rerio) and embryonic effects of chronic carnosine exposure.

Carnosine-like peptides (carnosine-LP) are a family of histidine derivatives that are present in the nervous system of various species and that exhibit antioxidant, anti-matrix-metalloproteinase, anti-excitotoxic, and free-radical scavenging properties. They are also neuroprotective in animal models of cerebral ischemia. Although the function of carnosine-LP is largely unknown, the hypothesis has been advanced that they play a role in the developing nervous system.

Asiatic acid, a pentacyclic triterpene from Centella asiatica, is neuroprotective in a mouse model of focal cerebral ischemia.

Asiatic acid, a triterpenoid derivative from Centella asiatica, has shown biological effects such as antioxidant, antiinflammatory, and protection against glutamate- or beta-amyloid-induced neurotoxicity. We investigated the neuroprotective effect of asiatic acid in a mouse model of permanent cerebral ischemia. Various doses of asiatic acid (30, 75, or 165 mg/kg) were administered orally at 1 hr pre- and 3, 10, and 20 hr postischemia, and infarct volume and behavioral deficits were evaluated at day 1 or 7 postischemia.

Differential neuroprotective effects of carnosine, anserine, and N-acetyl carnosine against permanent focal ischemia.

Carnosine (beta-alanyl-L-histidine) has been shown to exhibit neuroprotection in rodent models of cerebral ischemia. In the present study, we further characterized the effects of carnosine treatment in a mouse model of permanent focal cerebral ischemia and compared them with its related peptides anserine and N-acetylated carnosine. We also evaluated the efficacy of bestatin, a carnosinase inhibitor, in ameliorating ischemic brain damage.

Carnosine is neuroprotective against permanent focal cerebral ischemia in mice.

Background And Purpose: Carnosine is a naturally occurring dipeptide with multiple neuroprotective properties. In addition, it is well tolerated in high doses with minimal side effects. The purposes of this study were to determine whether carnosine is neuroprotective in permanent focal cerebral ischemia and to determine potential mechanisms of neuroprotection.

An element in the alpha1-tubulin promoter is necessary for retinal expression during optic nerve regeneration but not after eye injury in the adult zebrafish.

We have shown previously that a 1.696 kb upstream fragment of the goldfish alpha1-tubulin promoter was capable of driving green fluorescent protein (GFP) expression in the developing and regenerating zebrafish CNS in a pattern closely mimicking the endogenous alpha1-tubulin gene. Comparison of fish and rat alpha1-tubulin promoters identified a 64 bp region with a conserved repetitive homeodomain (HD) consensus sequence core (TAAT) and a nearby basic helix-loop-helix binding E-box sequence (CANNTG), which led us to speculate that it could be of importance for regulating alpha1-tubulin gene transcription.

Identities of sequestered proteins in aggregates from cells with induced polyglutamine expression.

Proteins with expanded polyglutamine (polyQ) tracts have been linked to neurodegenerative diseases. One common characteristic of expanded-polyQ expression is the formation of intracellular aggregates (IAs). IAs purified from polyQ-expressing cells were dissociated and studied by protein blot assay and mass spectrometry to determine the identity, condition, and relative level of several proteins sequestered within aggregates.

Intraneuronal aggregate formation and cell death after viral expression of expanded polyglutamine tracts in the adult rat brain.

Expanded polyglutamine (polyQ) tracts have been linked to a new class of human disease characterized by psychiatric/motor syndromes associated with specific patterns of neurodegeneration. We have used a direct viral approach to locally express expanded polyglutamine tracts fused to the green fluorescent protein (97Q-GFP) in the adult rat brain. We show that intrastriatal expression of 97Q-GFP causes the rapid formation of fibrillar, cytoplasmic, and ubiquitinated nuclear aggregates in neurons.

Prenatal gene therapy: can the technical hurdles be overcome?

Fifty years ago, a medical breakthrough in the prenatal diagnosis of genetic disorders was made with the introduction of amniocentesis. Until recently, there was little hope that diseases diagnosed in utero could be treated before birth. Today, prenatal gene therapy is emerging as a new concept for treating pre- and postnatal manifestations of genetic diseases and developmental disorders.

High level transactivation by a modified Bombyx ecdysone receptor in mammalian cells without exogenous retinoid X receptor.

Our studies of the Bombyx mori ecdysone receptor (BE) revealed that, unlike the Drosophila melanogaster ecdysone receptor (DE), treatment of BE with the ecdysone agonist tebufenozide stimulated high level transactivation in mammalian cells without adding an exogenous heterodimer partner. Gel mobility shift and transfection assays with both the ultraspiracle gene product (Usp) and retinoid X receptor heterodimer partners indicated that this property of BE stems from significantly augmented heterodimer complex formation and concomitant DNA binding. We have mapped this "gain of function" to determinants within the D and E domains of BE and demonstrated that, although the D domain determinant is sufficient for high affinity heterodimerization with Usp, both determinants are necessary for high affinity interaction with retinoid X receptor.

Gene transfer to the rodent placenta in situ. A new strategy for delivering gene products to the fetus.

The delivery of biologically active factors to the developing mammalian embryo by in utero gene transfer has generated considerable interest but limited success. The chorioallantoic placenta is a potential alternative target for providing therapeutic transgenes to the fetus during gestation. We demonstrate that somatic gene transfer to the midgestation rat placenta may be efficiently accomplished in situ through the implantation of a variety of genetically modified cells with different antigenic and growth properties.

The use of nonneuronal cells for gene delivery.

The implantation of genetically engineered nonneuronal cells can provide an effective method for achieving localized delivery of discrete molecules to the CNS or for providing substrates for regrowth of neural structures. Most primary nonneuronal cells have the advantage of being easily obtainable from the prospective host for ex vivo retrovirus-mediated genetic manipulation (most will be mitotic in culture) and reimplantation as an autologous graft (circumventing the problem of immune rejection). As primary cells, they are unlikely to be tumorigenic.

Gene therapy in the adult primate brain: intraparenchymal grafts of cells genetically modified to produce nerve growth factor prevent cholinergic neuronal degeneration.

Gene therapy may be a useful means of delivering substances to the brain that are capable of preventing neuronal degeneration. In the present experiment, we determined whether intraparenchymal transplants of primary autologous cells genetically modified to produce nerve growth factor (NGF) would prevent injury-induced degeneration of cholinergic neurons. Cultured primary monkey fibroblasts were genetically modified to produce human NGF, and secreted 13.

Regional differences in responsiveness of adult CNS axons to grafts of cells expressing human neurotrophin 3.

Neurotrophin 3 (NT3) belongs to the neurotrophin family, which also includes nerve growth factor, brain-derived neurotrophic factor, and neurotrophin 4/5. NT3 mRNA is widely expressed in the rodent nervous system, but the physiological function of the native protein is still unclear. Genetically modified cell lines that produce physiological amounts of NT3 can provide a useful tool in the elucidation of the NT3 effects in the adult central nervous system (CNS).