Comparison of four modeling tools for the prediction of potential distribution for non-indigenous weeds in the United States

This study compares four models for predicting the potential distribution of non-indigenous weed species in the conterminous U.S. The comparison focused on evaluating modeling tools and protocols as currently used for weed risk assessment or for predicting the potential distribution of invasive weeds. We used six weed species (three highly invasive and three less invasive non-indigenous species) that have been established in the U.S. for more than 75 years. The experiment involved providing non-U. S. location data to users familiar with one of the four evaluated techniques, who then developed predictive models that were applied to the United States without knowing the identity of the species or its U.S. distribution. We compared a simple GIS climate matching technique known as Proto3, a simple climate matching tool CLIMEX Match Climates, the correlative model MaxEnt, and a process model known as the Thornley Transport Resistance (TTR) model. Two experienced users ran each modeling tool except TTR, which had one user. Models were trained with global species distribution data excluding any U.S. data, and then were evaluated using the current known U.S. distribution. The influence of weed species identity and modeling tool on prevalence and sensitivity effects was compared using a generalized linear mixed model. Each modeling tool itself had a low statistical significance, while weed species alone accounted for 69.1 and 48.5% of the variance for prevalence and sensitivity, respectively. These results suggest that simple modeling tools might perform as well as complex ones in the case of predicting potential distribution for a weed not yet present in the United States. Considerations of model accuracy should also be balanced with those of reproducibility and ease of use. More important than the choice of modeling tool is the construction of robust protocols and testing both new and experienced users under blind test conditions that approximate operational conditions.     

Functional analysis of recombinant human and <Emphasis Type="Italic">Yarrowia lipolytica</Emphasis> <Emphasis Type="Italic">O</Emphasis>-GlcNAc transferases expressed in <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

O-linked β-N-acetylglucosamine (O-GlcNAc) glycosylation is an important post-translational modification in many cellular processes. It is mediated by O-GlcNAc transferases (OGTs), which catalyze the addition of O-GlcNAc to serine or threonine residues of the target proteins. In this study, we expressed a putative Yarrowia lipolytica OGT (YlOGT), the only homolog identified in the subphylum Saccharomycotina through bioinformatics analysis, and the human OGT (hOGT) as recombinant proteins in Saccharomyces cerevisiae, and performed their functional characterization. Immunoblotting assays using antibody against O-GlcNAc revealed that recombinant hOGT (rhOGT), but not the recombinant YlOGT (rYlOGT), undergoes auto-O-GlcNAcylation in the heterologous host S. cerevisiae. Moreover, the rhOGT expressed in S. cerevisiae showed a catalytic activity during in vitro assays using casein kinase II substrates, whereas no such activity was obtained in rYlOGT. However, the chimeric human-Y. lipolytica OGT, carrying the human tetratricopeptide repeat (TPR) domain along with the Y. lipolytica catalytic domain (CTD), mediated the transfer of O-GlcNAc moiety during the in vitro assays. Although the overexpression of full-length OGTs inhibited the growth of S. cerevisiae, no such inhibition was obtained upon overexpression of only the CTD fragment, indicating the role of TPR domain in growth inhibition. This is the first report on the functional analysis of the fungal OGT, indicating that the Y. lipolytica OGT retains its catalytic activity, although the physiological role and substrates of YlOGT remain to be elucidated.     

Site density of the sodium-calcium exchange carrier in reconstituted vesicles from bovine cardiac sarcolemma

The site density of the Na2+-Ca2+ exchanger in bovine cardiac sarcolemma was estimated from measurements of the fraction of reconstituted proteoliposomes exhibiting exchange activity. Sarcolemmal vesicles were solubilized with 1% Triton X-100 in the presence of either 100 mM NaCl or 100 mM KCl; after a 20-40-min incubation period on ice, sufficient KCl, NaCl, CaCl2, and soybean phospholipids were added to each extract to give final concentrations of 40 mM NaCl, 120 mM KCl, 0.1 mM CaCl2, and 10 mg/ml phospholipid. These mixtures were then reconstituted into proteoliposomes, and the rate of 45Ca2+ isotopic exchange was measured under equilibrium conditions. Control studies showed that Na+-Ca2+ exchange activity was completely lost if Na+ was not present during solubilization. The difference in 45Ca2+ uptake between vesicles initially solubilized in the presence or absence of NaCl therefore reflected exchange activity and corresponded to 3.1 +/- 0.3% of the total 45Ca2+ uptake by the entire population of vesicles, as measured in the presence of the Ca2+ ionophore A23187. Assuming that each vesicle with exchange activity contained 1 molecule of the Na+-Ca2+ exchange carrier, a site density of 10-20 pmol/mg of protein for the exchanger was calculated. The Vmax for Na+-Ca2+ exchange activity in the proteoliposomes was approximately 20 nmol/mg of protein.s which indicates that the turnover number of the exchange carrier is 1000 s-1 or more. Thus, the Na+-Ca2+ exchanger is a low density, high turnover transport system.     

Identification and Characterization of a Dual-Acting Antinematodal Agent against the Pinewood Nematode,Bursaphelenchus xylophilus

The pinewood nematode (PWN), Bursaphelenchus xylophilus, is a mycophagous and phytophagous pathogen responsible for the current widespread epidemic of the pine wilt disease, which has become a major threat to pine forests throughout the world. Despite the availability of several preventive trunk-injection agents, no therapeutic trunk-injection agent for eradication of PWN currently exists. In the characterization of basic physiological properties of B. xylophilus YB-1 isolates, we established a high-throughput screening (HTS) method that identifies potential hits within approximately 7 h. Using this HTS method, we screened 206 compounds with known activities, mostly antifungal, for antinematodal activities and identified HWY-4213 (1-n-undecyl-2-[2-fluorphenyl] methyl-3,4-dihydro-6,7-dimethoxy-isoquinolinium chloride), a highly water-soluble protoberberine derivative, as a potent nematicidal and antifungal agent. When tested on 4 year-old pinewood seedlings that were infected with YB-1 isolates, HWY-4213 exhibited a potent therapeutic nematicidal activity. Further tests of screening 39 Caenorhabditis elegans mutants deficient in channel proteins and B. xylophilus sensitivity to Ca²⁺ channel blockers suggested that HWY-4213 targets the calcium channel proteins. Our study marks a technical breakthrough by developing a novel HTS method that leads to the discovery HWY-4213 as a dual-acting antinematodal and antifungal compound.     

Apamin inhibits hepatic fibrosis through suppression of transforming growth factor β1-induced hepatocyte epithelial–mesenchymal transition

Apamin is an integral part of bee venom, as a peptide component. It has long been known as a highly selective block Ca²⁺-activated K⁺ (SK) channels. However, the cellular mechanism and anti-fibrotic effect of apamin in TGF-β1-induced hepatocytes have not been explored. In the present study, we investigated the anti-fibrosis or anti-EMT mechanism by examining the effect of apamin on TGF-β1-induced hepatocytes. AML12 cells were seeded at ∼60% confluence in complete growth medium. Twenty-four hours later, the cells were changed to serum free medium containing the indicated concentrations of apamin. After 30 min, the cells were treated with 2 ng/ml of TGF-β1 and co-cultured for 48 h. Also, we investigated the effects of apamin on the CCl₄-induced liver fibrosis animal model. Treatment of AML12 cells with 2 ng/ml of TGF-β1 resulted in loss of E-cadherin protein at the cell–cell junctions and concomitant increased expression of vimentin. In addition, phosphorylation levels of ERK1/2, Akt, Smad2/3 and Smad4 were increased by TGF-β1 stimulation. However, cells treated concurrently with TGF-β1 and apamin retained high levels of localized expression of E-cadherin and showed no increase in vimentin. Specifically, treatment with 2 μg/ml of apamin almost completely blocked the phosphorylation of ERK1/2, Akt, Smad2/3 and Smad4 in AML12 cells. In addition, apamin exhibited prevention of pathological changes in the CCl₄-injected animal models. These results demonstrate the potential of apamin for the prevention of EMT progression induced by TGF-β1 in vitro and CCl₄-injected in vivo.     

Relationship of Behavioral Interactions during an Animal-assisted Intervention in Assisted Living to Health-related Outcomes

ABSTRACT

In recent research involving assisted-living residents with mild to moderate cognitive impairment, a structured 12-week Pet Assisted Living (PAL) intervention led to improved physical activity (PA) and mood. Receipt of intervention is important to the efficacy of behavioral interventions. We assessed the behavioral interactions (BIs: looking at, talking to, touching, giving treats to, brushing, and walking the dog) of residents during PAL intervention sessions and evaluated their relationships to changes in PA and mood. Residents with mild to moderate cognitive impairment in seven small assisted-living facilities were randomized by facility to the 12-week PAL or reminiscing interventions. Outcomes included PA and mood. PA was assessed monthly with 24-hour actigraph and Barthel Index, and mood was assessed with the Cornell Scale for Depression in Dementia. Residents of four facilities (n = 22) received the PAL intervention which included bi-weekly activities designed to encourage maintenance or improvement of PA and mood. During each PAL session, participants’ engagement in each BI was noted. Engagement in BIs varied between residents and over sessions. BIs were not correlated with degree of cognitive impairment. In linear mixed models, the more participants walked the dog the more their PA changed, and the more participants looked at the dog the more their moods changed (ps < 0.05). Participants varied in their engagement in BIs. Two specific BIs were related to improvements in PA and mood. Finer assessment of BIs during animal-assisted interventions may enable understanding of their relationships to specific outcomes.