Assessment of sediment porewater toxicity in Biscayne National Park with sea urchin (Lytechinus variegatus) embryos.

The sea urchin embryo development toxicity test was used to investigate toxicity of the benthic substrate in Biscayne National Park (BISC). Twenty-five sites were selected based upon a high potential for anthropogenic stressor input (e. g., hydrocarbons, personal care products, nutrients, etc.) or proximity to coral reef habitats. We found that sediment interstitial water (porewater) was toxic to urchin embryos at 22 of 25 sites. Healthy sites included two coral reefs (Anniversary Reef and Marker 14 Reef) and Turkey Point Channel. Discrete areas of BISC have highly toxic sediments and the presence of sediment contaminants could negatively impact reproduction, growth and population density of benthic invertebrates, such as corals. Results of the sea urchin embryo development toxicity test can be used as a baseline assessment for monitoring improvements or degradation in ecosystem health and could be a valuable tool to investigate the suitability of degraded habitats for future reef restoration. Since the last comprehensive environmental assessment of BISC was performed in 1999, further investigation into the sources of toxicity at BISC is needed.

Interactive Effects of HLA and GM Alleles on the Development of Alzheimer Disease.

OBJECTIVE: We investigated whether particular immunoglobulin GM (γ marker) alleles-individually or epistatically with a known human leukocyte antigen (HLA) risk allele-were associated with the development of Alzheimer disease (AD). METHODS: Using a prospective cohort study design, we genotyped DNA samples from 209 African American (AA) and 638 European American (EA) participants for IgG1 (GM 3 and GM 17), IgG2 (GM 23+ and GM 23-), and HLA-DRB1 rs9271192 (A/C) alleles by TaqMan and rhAMP genotyping assays. RESULTS: In EA subjects, none of the GM or HLA alleles-individually or epistatically-were associated with time to development of AD. In AA subjects, GM and HLA alleles individually were not associated with time to development of AD. However, there was a significant interaction: In the presence of GM 3 (i.e., GM 3/3 and GM 3/17 subjects), the presence of the HLA-C allele was associated with a 4-fold increase in the likelihood of developing AD compared with its absence (hazard ratio [HR] 4.17, 95% CI, 1.28-13.58). In the absence of GM 3 (GM 17/17 subjects), however, the presence of the HLA-C allele was not associated with time to development of AD (HR 1.10, 95% CI, 0.50-2.41). CONCLUSIONS: These results show that particular GM and HLA alleles epistatically contribute to the development of AD.

An Ig γ Marker Genotype Is a Strong Risk Factor for Alzheimer Disease, Independent of Apolipoprotein E ε4 Genotype.

Increasing evidence implicates HSV type 1 (HSV1) in the pathogenesis of late-onset Alzheimer disease (AD). HSV1 has evolved highly sophisticated strategies to evade host immunosurveillance. One strategy involves encoding a decoy Fcγ receptor (FcγR), which blocks Fc-mediated effector functions, such as Ab-dependent cellular cytotoxicity. Ig γ marker (GM) allotypes, encoded by highly polymorphic IGHG genes on chromosome 14q32, modulate this immunoevasion strategy, and thus may act as effect modifiers of the HSV1-AD association. In this nested case-control human study, 365 closely matched case-control pairs-whose blood was drawn on average 9.6 y before AD diagnosis-were typed for GM alleles by a TaqMan genotyping assay. APOE genotype and a genetic risk score based on nine additional previously known AD risk genes (ABCA7, BIN1, CD33, CLU, CR1, EPHA1, MS4A4E, NECTIN2, and PICALM) were extracted from a genome-wide association study analysis. Antiviral Abs were measured by ELISA. Conditional logistic regression models were applied. The distribution of GM 3/17 genotypes differed significantly between AD cases and controls, with higher frequency of GM 17/17 homozygotes in AD cases as compared with controls (19.8 versus 10.7%, p = 0.001). The GM 17/17 genotype was associated with a 4-fold increased risk of AD (odds ratio 4.142, p < 0.001). In conclusion, the results of this study demonstrate that Ig GM 17/17 genotype contributes to the risk of later AD development, independent of apolipoprotein ε4 genotype and other AD risk genes, and explain, at least in part, why every HSV1-infected person is not equally likely to develop HSV1-associated AD.

Immunoglobulin Genes and Immunity to HSV1 in Alzheimer's Disease.

Although genome-wide association studies (GWAS) of late-onset Alzheimer's disease (AD) have identified numerous genes that influence the risk for disease, the majority of the genetic variance of AD remains uncharacterized. Furthermore, current GWAS, despite their name, do not evaluate all genes in the human genome. One such gene complex is immunoglobulin GM (γ marker) genes on chromosome 14. GM genes are excellent candidate genes for AD because they influence immunity to herpes simplex virus type 1 (HSV1), which has been implicated in AD pathology by an increasing number of reports. The aim of this investigation was to determine if particular GM genotypes were associated with AD and mild cognitive impairment (MCI), and whether they contributed to the interindividual differences in the level of anti-HSV1 IgG antibodies. A total of 141 HSV1 seropositive individuals-56 AD patients, 48 MCI individuals, and 37 sex- and age-matched healthy controls-were characterized for GM alleles 3, 17, and 23. The homozygosity for the GM 3 allele was significantly associated with MCI (p = 0.025). GM 3/17 heterozygous AD patients had significantly higher levels of anti-HSV1 antibodies than the healthy controls expressing the same genotype (p = 0.0004). Among MCI subjects, the GM 3/17 genotype was associated with significantly higher level of anti-HSV1 antibodies as compared to the GM 17/17 homozygous genotype (pc = 0.040). Among AD patients, the GM 23+/-genotype was significantly associated with anti-HSV1 antibody responses (pc = 0.025). These results suggest that GM genes could act as potential unifiers of the genetic and viral etiology of AD.

Development of a Non-Invasive Blink Reflexometer.

Qualitative assessments of the blink reflex are used clinically to assess neurological status in critical care, operating room, and rehabilitative settings. Despite decades of literature supporting the use of quantitative measurements of the blink reflex in the evaluation of multiple neurological disorders, clinical adoption has failed. Thus, there remains an unmet clinical need for an objective, portable, non-invasive metric of neurological health that can be used in a variety of settings. We have developed a high-speed videography-based device to trigger, record, and analyze a blink reflex. A pilot study was performed to compare the device's measurements to the published literature of electromyographic measurements, currently the gold standard. The study results indicate that the device is a viable tool to obtain fast, objective, and quantitative metrics of a blink reflex, and has promise as a non-invasive diagnostic assessment of neurological health.

Control of pollen-mediated gene flow in transgenic trees.

Pollen elimination provides an effective containment method to reduce direct gene flow from transgenic trees to their wild relatives. Until now, only limited success has been achieved in controlling pollen production in trees. A pine (Pinus radiata) male cone-specific promoter, PrMC2, was used to drive modified barnase coding sequences (barnaseH102E, barnaseK27A, and barnaseE73G) in order to determine their effectiveness in pollen ablation. The expression cassette PrMC2-barnaseH102E was found to efficiently ablate pollen in tobacco (Nicotiana tabacum), pine, and Eucalyptus (spp.). Large-scale and multiple-year field tests demonstrated that complete prevention of pollen production was achieved in greater than 95% of independently transformed lines of pine and Eucalyptus (spp.) that contained the PrMC2-barnaseH102E expression cassette. A complete pollen control phenotype was achieved in transgenic lines and expressed stably over multiple years, multiple test locations, and when the PrMC2-barnaseH102E cassette was flanked by different genes. The PrMC2-barnaseH102E transgenic pine and Eucalyptus (spp.) trees grew similarly to control trees in all observed attributes except the pollenless phenotype. The ability to achieve the complete control of pollen production in field-grown trees is likely the result of a unique combination of three factors: the male cone/anther specificity of the PrMC2 promoter, the reduced RNase activity of barnaseH102E, and unique features associated with a polyploid tapetum. The field performance of the PrMC2-barnaseH102E in representative angiosperm and gymnosperm trees indicates that this gene can be used to mitigate pollen-mediated gene flow associated with large-scale deployment of transgenic trees.

AFLP analysis of a worldwide collection of Didymella bryoniae.

Didymella bryoniae (anamorph Phoma cucurbitacearum) is an ascomycete that causes gummy stem blight, a foliar disease that occurs on cucurbits in greenhouses and fields throughout the world. In a previous study using RAPD analysis, little genetic diversity was found among isolates of D. bryoniae from New York and South Carolina, USA. Here we report the use of amplified fragment length polymorphism (AFLP) analysis to assess the genetic variation within a worldwide collection of D. bryoniae, 102 field and greenhouse isolates from ten states in the USA (California, Delaware, Florida, Georgia, Indiana, Maryland, Michigan, Oklahoma, South Carolina, and Texas) and seven other countries (Australia, Canada, China, Greece, Israel, Sweden, and The Netherlands) were examined. Seven different AFLP primer-pair combinations generated 450 bands, of which 134 were polymorphic (30%). Using cluster analysis, two groups and a total of seven subgroups were delineated. Representative isolates varied in their virulence on muskmelon and watermelon seedlings, but the degree of virulence was not strongly associated with AFLP groupings. However, isolates from the northern USA grouped separately from isolates originating from the southern USA.