Transgene effects on rhizodeposition: Evidence from molecular-chemical screening by Pyrolysis-Field Ionisation Mass Spectrometry (Py-FIMS)

Rhizodeposition plays an important role in the C and N cycle of ecosystems, since it essentially reflects the interaction between plant, soil and soil microorganisms. The molecular-chemical characterisation of rhizodeposition is often limited to selected compound classes (e.g., carbohydrates and amino acids). A more comprehensive analytical approach is based on the molecular-chemical “fingerprint” revealed by Pyrolysis-Field Ionisation Mass Spectrometry (Py-FIMS).

The presented results give evidence of specific effects in conjunction with soil type, crop, variety, transgenes and mycorrhizal colonisation on the molecular-chemical composition of rhizodeposition. The experiments included various crops (maize, potato, vetch, willow and poplar), which were grown in leaching vessels under controlled environmental conditions on different soil types. The experimental design covered different varieties for maize, trangenes (vetch and potato) and inoculation with mycorrhizal fungi (poplar). All rhizodeposits were leached at defined growth stages and analysed by Py-FIMS.

The Py-FIMS data evaluation by multivariate statistics enabled a clear discrimination by all factors. Among these factors soil type and the crop had the largest effect on the molecular-chemical composition. By contrast, variety and transgene effects were subordinated.
The results of the multivariate statistics for crops, grown on the same soil (maize, potato, vetch), revealed 23 mass signals with highest discriminating power (P<0.001, multiple F-test). About 90 % of those signals can be assigned to known substances, based on our mass spectrometric in-house library and/or the literature. Further investigation will be focused on structural elucidation of the previously unassigned mass signals.
&#xa

Küstenschutzwälder im Interessenskonflikt zwischen Nutzung und ökologischer Funktion - der "Gespensterwald Nienhagen" in Mecklenburg-Vorpommern

Im Gespensterwald Nienhagen als Teil des Küstenschutzwaldes Nienhäger Holz (Ostseebad Nienhagen, Mecklenburg-Vorpommern) wurden 2012 die Böden in Abhängigkeit von der Nutzungsart (Hochwald, Verjüngung und Acker als Referenz) und dem Abstand vom Kliff untersucht. Anhand der Gehalte an organischer Substanz und der Aggregierungseigenschaften (Aggregatgrößenverteilung und Aggregatstabilität) wurden deutliche Differenzierungen nachgezeichnet, die den nachteiligen Einfluss zunehmender Trittbelastung im Kliffbereich belegen

Identifying Host Genetic Risk Factors in the Context of Public Health Surveillance for Invasive Pneumococcal Disease

Host genetic factors that modify risk of pneumococcal disease may help target future public health interventions to individuals at highest risk of disease. We linked data from population-based surveillance for invasive pneumococcal disease (IPD) with state-based newborn dried bloodspot repositories to identify biological samples from individuals who developed invasive pneumococcal disease. Genomic DNA was extracted from 366 case and 732 anonymous control samples. TagSNPs were selected in 34 candidate genes thought to be associated with host response to invasive pneumococcal disease, and a total of 326 variants were successfully genotyped. Among 543 European Americans (EA) (182 cases and 361 controls), and 166 African Americans (AA) (53 cases and 113 controls), common variants in surfactant protein D (SFTPD) are consistently underrepresented in IPD. SFTPD variants with the strongest association for IPD are intronic rs17886286 (allelic OR 0.45, 95% confidence interval (CI) [0.25, 0.82], with p = 0.007) in EA and 5′ flanking rs12219080 (allelic OR 0.32, 95%CI [0.13, 0.78], with p = 0.009) in AA. Variants in CD46 and IL1R1 are also associated with IPD in both EA and AA, but with effects in different directions; FAS, IL1B, IL4, IL10, IL12B, SFTPA1, SFTPB, and PTAFR variants are associated (p≤0.05) with IPD in EA or AA. We conclude that variants in SFTPD may protect against IPD in EA and AA and genetic variation in other host response pathways may also contribute to risk of IPD. While our associations are not corrected for multiple comparisons and therefore must be replicated in additional cohorts, this pilot study underscores the feasibility of integrating public health surveillance with existing, prospectively collected, newborn dried blood spot repositories to identify host genetic factors associated with infectious diseases

Assessing Change in Student Critical Thinking for Introduction to Sociology Classes

Although there is widespread agreement among academics that critical thinking is an important component to the college classroom, there is little empirical evidence to verify that it is being taught in courses. Using four sections of introductory sociology, we developed an experimental design using pretests and posttests to assess students’ critical thinking skills. Controlling for grade point average, cumulative credit hours completed, gender, race/ethnicity, socioeconomic status, instructor, and initial levels of critical thinking, being in the experimental group had a statistically significant impact on critical thinking at the end of the semester. Thus, inclusion of writing assignments and classroom discussion designed to enhance creative thought processes for the experimental group helped students improve from one-dimensional thinking toward more multistructural analysis

Potential Utility of Plasma P-Tau and Neurofilament Light Chain as Surrogate Biomarkers for Preventive Clinical Trials

OBJECTIVE: To test the utility of longitudinal changes in plasma phosphorylated tau 181 (p-tau181) and neurofilament light chain (NfL) as surrogate markers for clinical trials targeting cognitively unimpaired (CU) populations. METHODS: We estimated the sample size needed to test a 25% drug effect with 80% of power at a 0.05 level on reducing changes in plasma markers in CU participants from Alzheimer's Disease Neuroimaging Initiative database. RESULTS: We included 257 CU individuals (45.5% males; mean age = 73 [6] years; 32% β-amyloid [Aβ] positive). Changes in plasma NfL were associated with age, whereas changes in plasma p-tau181 with progression to amnestic mild cognitive impairment. Clinical trials using p-tau181 and NfL would require 85% and 63% smaller sample sizes, respectively, for a 24-month than a 12-month follow-up. A population enrichment strategy using intermediate levels of Aβ PET (Centiloid 20-40) further reduced the sample size of the 24-month clinical trial using p-tau181 (73%) and NfL (59%) as a surrogate. DISCUSSION: Plasma p-tau181/NfL can potentially be used to monitor large-scale population interventions in CU individuals. The enrollment of CU with intermediate Aβ levels constitutes the alternative with the largest effect size and most cost-effective for trials testing drug effect on changes in plasma p-tau181 and NfL

Astrocyte biomarker signatures of amyloid-β and tau pathologies in Alzheimer’s disease

Astrocytes can adopt multiple molecular phenotypes in the brain of Alzheimer's disease (AD) patients. Here, we studied the associations of cerebrospinal fluid (CSF) glial fibrillary acidic protein (GFAP) and chitinase-3-like protein 1 (YKL-40) levels with brain amyloid-β (Aβ) and tau pathologies. We assessed 121 individuals across the aging and AD clinical spectrum with positron emission tomography (PET) brain imaging for Aβ ([18F]AZD4694) and tau ([18F]MK-6240), as well as CSF GFAP and YKL-40 measures. We observed that higher CSF GFAP levels were associated with elevated Aβ-PET but not tau-PET load. By contrast, higher CSF YKL-40 levels were associated with elevated tau-PET but not Aβ-PET burden. Structural equation modeling revealed that CSF GFAP and YKL-40 mediate the effects of Aβ and tau, respectively, on hippocampal atrophy, which was further associated with cognitive impairment. Our results suggest the existence of distinct astrocyte biomarker signatures in response to brain Aβ and tau accumulation, which may contribute to our understanding of the complex link between reactive astrogliosis heterogeneity and AD progression

Astrocyte reactivity influences amyloid-β effects on tau pathology in preclinical Alzheimer's disease

An unresolved question for the understanding of Alzheimer's disease (AD) pathophysiology is why a significant percentage of amyloid-β (Aβ)-positive cognitively unimpaired (CU) individuals do not develop detectable downstream tau pathology and, consequently, clinical deterioration. In vitro evidence suggests that reactive astrocytes unleash Aβ effects in pathological tau phosphorylation. Here, in a biomarker study across three cohorts (n = 1,016), we tested whether astrocyte reactivity modulates the association of Aβ with tau phosphorylation in CU individuals. We found that Aβ was associated with increased plasma phosphorylated tau only in individuals positive for astrocyte reactivity (Ast+). Cross-sectional and longitudinal tau-positron emission tomography analyses revealed an AD-like pattern of tau tangle accumulation as a function of Aβ only in CU Ast+ individuals. Our findings suggest astrocyte reactivity as an important upstream event linking Aβ with initial tau pathology, which may have implications for the biological definition of preclinical AD and for selecting CU individuals for clinical trials

Evolution of Genome Size and Complexity in Pinus

BACKGROUND: Genome evolution in the gymnosperm lineage of seed plants has given rise to many of the most complex and largest plant genomes, however the elements involved are poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: Gymny is a previously undescribed retrotransposon family in Pinus that is related to Athila elements in Arabidopsis. Gymny elements are dispersed throughout the modern Pinus genome and occupy a physical space at least the size of the Arabidopsis thaliana genome. In contrast to previously described retroelements in Pinus, the Gymny family was amplified or introduced after the divergence of pine and spruce (Picea). If retrotransposon expansions are responsible for genome size differences within the Pinaceae, as they are in angiosperms, then they have yet to be identified. In contrast, molecular divergence of Gymny retrotransposons together with other families of retrotransposons can account for the large genome complexity of pines along with protein-coding genic DNA, as revealed by massively parallel DNA sequence analysis of Cot fractionated genomic DNA. CONCLUSIONS/SIGNIFICANCE: Most of the enormous genome complexity of pines can be explained by divergence of retrotransposons, however the elements responsible for genome size variation are yet to be identified. Genomic resources for Pinus including those reported here should assist in further defining whether and how the roles of retrotransposons differ in the evolution of angiosperm and gymnosperm genomes