Presidential Address: The Aquatic Plant Management Society and Our Future Sphere of Influence

Presidential address of Alison M. Fo

Influence of Water Depth on the Rate of Expansion of Giant Cutgrass Populations and Management Implications

Giant cutgrass ( Zizaniopsis miliacea (Michx.) Doell. & Asch.), a tall emergent grass native to the southeastern United States, was studied in Lake Seminole where it formed large expanding stands, and Lake Alice where it was confined to a stable narrow fringe

Termites Create Spatial Structure And Govern Ecosystem Function By Affecting N-2 Fixation In An East African Savanna

The mechanisms by which even the clearest of keystone or dominant species exert community-wide effects are only partially understood in most ecosystems. This is especially true when a species or guild influences community-wide interactions via changes in the abiotic landscape. Using stable isotope analyses, we show that subterranean termites in an East African savanna strongly influence a key ecosystem process: atmospheric nitrogen fixation by a monodominant tree species and its bacterial symbionts. Specifically, we applied the N-15 natural abundance method in combination with other biogeochemical analyses to assess levels of nitrogen fixation by Acacia drepanolobium and its effects on co-occurring grasses and forbs in areas near and far from mounds and where ungulates were or were not excluded. We find that termites exert far stronger effects than do herbivores on nitrogen fixation. The percentage of nitrogen derived from fixation in Acacia drepanolobium trees is higher (55-80%) away from mounds vs. near mounds (40-50%). Mound soils have higher levels of plant available nitrogen, and Acacia drepanolobium may preferentially utilize soil-based nitrogen sources in lieu of fixed nitrogen when these sources are readily available near termite mounds. At the scale of the landscape, our models predict that termite/soil derived nitrogen sources influence \u3e50% of the Acacia drepanolobium trees in our system. Further, the spatial extent of these effects combine with the spacing of termite mounds to create highly regular patterning in nitrogen fixation rates, resulting in marked habitat heterogeneity in an otherwise uniform landscape. In summary, we show that termite-associated effects on nitrogen processes are not only stronger than those of more apparent large herbivores in the same system, but also occur in a highly regular spatial pattern, potentially adding to their importance as drivers of community and ecosystem structure

Prevalence, Distribution, and Risk Factor Correlates of High Thoracic Periaortic Fat in the Framingham Heart Study

Background: Thoracic periaortic adipose tissue (TAT) is associated with atherosclerosis and cardiovascular disease (CVD) risk factors and may play a role in obesity‐mediated vascular disease. We sought to determine the prevalence, distribution, and risk factor correlates of high TAT. Methods and Results: Participants from the Framingham Heart Study (n=3246, 48% women, mean age 51.1 years) underwent multidetector computed tomography; high TAT and visceral adipose tissue (VAT) were defined on the basis of sex‐specific 90th percentiles in a healthy referent sample. The prevalence of high TAT was 38.1% in women and 35.7% in men. Among individuals without high VAT, 10.1% had high TAT. After adjustment for age and VAT, both women and men with high TAT in the absence of high VAT were older and had a higher prevalence of CVD (P<0.0001) compared with those without high TAT. In addition, men in this group were more likely to be smokers (P=0.02), whereas women were more likely to have low high‐density lipoprotein cholesterol (P=0.005). Conclusions: Individuals in our community‐based sample with high TAT in the absence of high VAT were characterized by an adverse cardiometabolic profile. This adipose tissue phenotype may identify a subset of individuals with distinct metabolic characteristics

A critical review of the epidemiological evidence of effects of air pollution on dementia, cognitive function and cognitive decline in adult population

Dementia is arguably the most pressing public health challenge of our age. Since dementia does not have a cure,identifying risk factors that can be controlled has become paramount to reduce the personal, societal and eco-nomic burden of dementia. The relationship between exposure to air pollution and effects on cognitive function,cognitive decline and dementia has stimulated increasing scientific interest in the past few years. This review ofthe literature critically examines the available epidemiological evidence of associations between exposure to am-bient air pollutants, cognitive performance, acceleration of cognitive decline, risk of developing dementia, neuro-imaging and neurological biomarker studies, following Bradford Hill guidelines for causality.The evidence reviewed has been consistent in reporting associations between chronic exposure to air pollutionand reduced global cognition, as well as impairment in specific cognitive domains including visuo-spatial abili-ties. Cognitive decline and dementia incidence have also been consistently associated with exposure to air pollu-tion. The neuro-imaging studies reviewed report associations between exposure to air pollution and whitematter volume reduction. Other reported effects include reduction in gray matter, larger ventricular volume,and smaller corpus callosum. Findings relating to ischemic (white matter hyperintensities/silent cerebralinfarcts) and hemorrhagic (cerebral microbleeds) markers of cerebral small vessel disease have been heteroge-neous, as have observations on hippocampal volume and air pollution. The few studies available on neuro-inflammation tend to report associations with exposure to air pollution. everal effect modifiers have been suggested in the literature, but more replication studies are required. Tradi-tional confounding factors have been controlled or adjusted for in most of the reviewed studies. Additional con-founding factors have also been considered, but the inclusion of these has varied among the different studies.Despite all the efforts to adjust for confounding factors, residual confounding cannot be completely ruled out, es-pecially since the factors affecting cognition and dementia are not yet fully understood.The available evidence meets many of the Bradford Hill guidelines for causality. The reported associations be-tween a range of air pollutants and effects oncognitive function in older people,including the acceleration of cog-nitive decline and the induction of dementia, are likely to be causal in nature.However, the diversity of study designs, air pollutants and endpoints examined precludes the attribution of theseadverse effects to a single class of pollutant and makes meta-analysis inappropriate

Methodology for reliable and reproducible cryopreservation of human cervical tissue

BACKGROUND: In order to conduct laboratory studies on donated cervical tissue at suitable times an effective and reliable cryopreservation protocol for cervical tissue is required. METHODS: An active freezing approach was devised utilising 10% dimethyl sulfoxide in foetal bovine serum as a cryoprotective agent with a cooling rate of 1 °C/min to -50 °C then 10 °C/min to -120 °C; a related thawing protocol was also optimised which would allow for the bio-banking of cervical tissue. Viability of freshly harvested cervical tissue was compared to frozen-thawed samples utilising colorimetric MTT assay. In parallel, fresh and freeze-thawed samples were cultured and tested on days 1, 7 and 14 to determine whether bio-banking had detrimental effects on tissue viability over time. RESULTS: Repeat testing revealed that tissue viability between fresh and freeze-thawed wasand freeze-thawed samples was comparable at all four time points (days 0, 1, 7 and 14) with no apparent reductions of viability, thus demonstrating this method of cryopreserving cervical tissue is reliable and reproducible, without detrimental effects on live tissue culture. We believe this methodology creates the opportunity for bio-banking donated cervical tissues, which aids improved experimental design and reduces time pressures and wastage

Targeted Nasal Vaccination Provides Antibody-Independent Protection Against Staphylococcus aureus

Despite showing promise in preclinical models, anti-Staphylococcus aureus vaccines have failed in clinical trials. To date, approaches have focused on neutralizing/opsonizing antibodies; however, vaccines exclusively inducing cellular immunity have not been studied to formally test whether a cellular-only response can protect against infection. We demonstrate that nasal vaccination with targeted nanoparticles loaded with Staphylococcus aureus antigen protects against acute systemic S. aureus infection in the absence of any antigen-specific antibodies. These findings can help inform future developments in staphylococcal vaccine development and studies into the requirements for protective immunity against S. aureu