Modelling inactivation by aqueous chlorine dioxide of Dothiorella gregaria Sacc. and Fusarium tricinctum (Corda) Sacc. spores inoculated on fresh chestnut kernel

Aims: To model survival curves of Dothiorella gregaria Sacc. and Fusarium tricinctum (Corda) Sacc. spores inoculated on fresh chestnut kernel exposed to aqueous chlorine dioxide (ClO₂). Methods and Results: Spores of two dominant spoilage fungi, D. gregaria and F. tricinctum, were inoculated onto chestnut kernel and treated with ClO₂. The inactivation efficacy of ClO₂ treatment increased with ClO₂ concentration and treatment time. The Weibull model was the best model to describe the ClO₂ survival curves of D. gregaria, while the modified Gompertz model was most appropriate for fitting the survival curves of F. tricinctum. Within the range of ClO₂ concentration from 3 to 7 mg l^?1, the n values in the Weibull model were similar. The b value in the Weibull model and decimal logarithms of the M, B and C values in the modified Gompertz model had linear relationships with ClO₂ concentration. After simplification, these two models still provided acceptable predictions. Conclusion: Applying models for describing survival curves of fungal spores on chestnut kernel by aqueous ClO₂ was feasible. Significance and Impact of the Study: This work would promote the application of ClO₂ sanitizing technique and mathematical models when preventing the occurrence of chestnut kernel decay.     

Cholesterol esterification and atherogenic index of plasma correlate with lipoprotein size and findings on coronary angiography

We examined the association between rate of cholesterol esterification in plasma depleted of apolipoprotein B-containing lipoproteins (FER(HDL)), atherogenic index of plasma (AIP) [(log (TG/HDL-C)], concentrations, and size of lipoproteins and changes in coronary artery stenosis in participants in the HDL-Atherosclerosis Treatment Study. A total of 160 patients was treated with simvastatin (S), niacin (N), antioxidants (A) and placebo (P) in four regimens. FER(HDL) was measured using a radioassay; the size and concentration of lipoprotein subclasses were determined by nuclear magnetic resonance spectroscopy. The S+N and S+N+A therapy decreased AIP and FER(HDL), reduced total VLDL (mostly the large and medium size particles), decreased total LDL particles (mostly the small size), and increased total HDL particles (mostly the large size). FER(HDL) and AIP correlated negatively with particle sizes of HDL and LDL, positively with VLDL particle size, and closely with each other (r = 0.729). Changes in the proportions of small and large lipoprotein particles, which were reflected by FER(HDL) and AIP, corresponded with findings on coronary angiography. Logistic regression analysis of the changes in the coronary stenosis showed that probability of progression was best explained by FER(HDL) (P = 0.005). FER(HDL) and AIP reflect the actual composition of the lipoprotein spectrum and thus predict both the cardiovascular risk and effectiveness of therapy. AIP is already available for use in clinical practice as it can be readily calculated from the routine lipid profile.     

东北主要树种倒木分解释放的CO2通量

在倒木丰富的森林生态系统中,倒木分解释放的CO2通量(RCWD)是生态系统碳收支中不容忽视的一个组分。采用红外气体分析法(Li-6400IRGA)测定东北东部山区典型温带天然次生林中11个主要树种的RCWD及其相关环境因子。主要研究目标包括:比较11个树种的RCWD、倒木温度(TCWD)和倒木含水量(WCWD);量化RCWD与TCWD和WCWD的关系;量化RCWD的季节动态。研究结果表明:白桦、山杨、紫椴、胡桃楸、蒙古栎、色木槭、春榆、红松、黄菠萝、落叶松和水曲柳在测定期间RCWD的平均值分别为:10.64、8.38、7.85、6.59、6.01、4.07、3.88、2.55、2.29、1.96μmolCO.2m-.2s-1和1.90μmolCO.2m-.2s-1。软阔叶树种的RCWD最高;针叶树种的RCWD总体上低于阔叶树种的。在整个测定期间,不同树种的TCWD虽然没有显著性差异(p>0.1),但是其WCWD差异极显著(p<0.001)。树种、倒木个体、倒木所处的立地状况及其交互作用均显著地影响RCWD,但其影响程度因树种而异。所有树种的TCWD、WCWD及其交互作用显著地(p<0.01)影响RCWD;包括了这些作用的RCWD模型解释了39.9%~72.9%的RCWD变异。不同树种RCWD的季节变化呈现基本一致的单峰曲线格局,主要受TCWD的驱动;而WCWD主要影响RCWD的季节内变化和树种间的差异。     

A multi-century eastern white pine tree-ring chronology developed from salvaged river logs and its utility for dating heritage structures in Canada's National Capital Region

The early settlement history of Canada's National Capital Region, including Ottawa (Ontario) and Gatineau (Québec), was shaped in large part by the towering eastern white pine (Pinus strobus) forests that once covered the Ottawa Valley and fuelled a lucrative lumber export industry spanning the 19th and much of the 20th century. Some of the first dwellings and farmsteads of this era are still standing and serve as reminders of this history. A crucial piece of information in the assessment of a structure's heritage value is its date of construction. Unfortunately, this information is not always known and is approximated based on construction styles and other sources of information. In this study, dendroarchaeology methods are applied to constrain the construction dates of six historic structures in the National Capital Region of 19th century vintage. A multi-century (AD 1670–2009) eastern white pine ring-width chronology was developed for dating the study structures using cross sections from sunken logs recovered from the Ottawa River and cores from live trees from the Petawawa Research Forest. The tree-ring inferred construction dates for the six structures ranged from 1830 to 1878. For most structures, historical records about the property or first inhabitants were available to corroborate the results. The ring-width chronologies of the individual structures were well correlated with the regional chronology (r_avg = 0.63, p ≤ 0.01), and this regional coherence clearly demonstrates the value of tree-rings for heritage structure assessments and reconstructing the settlement history of this region.     

Effects of clonal fragmentation on intraspecific competition of a stoloniferous floating plant

Disturbance is common and can fragment clones of plants. Clonal fragmentation may affect the density and growth of ramets so that it could alter intraspecific competition. To test this hypothesis, we grew one (low density), five (medium density) or nine (high density) parent ramets of the floating invasive plant Pistia stratiotes in buckets, and newly produced offspring ramets were either severed (with fragmentation) or remained connected to parent ramets (no fragmentation). Increasing density reduced biomass of the whole clone (i.e. parent ramet plus its offspring ramets), showing intense intraspecific competition. Fragmentation decreased biomass of offspring ramets, but increased biomass of parent ramets and the whole clone, suggesting significant resource translocation from parent to offspring ramets when clones were not fragmented. There was no interaction effect of density x fragmentation on biomass of the whole clone, and fragmentation did not affect competition intensity index. We conclude that clonal fragmentation does not alter intraspecific competition between clones of P. stratiotes, but increases biomass production of the whole clone. Thus, fragmentation may contribute to its interspecific competitive ability and invasiveness, and intentional fragmentation should not be recommended as a measure to stop the rapid growth of this invasive species.     

Removal and inactivation of human immunodeficiency virus (HIV-1) by cold ethanol fractionation and pasteurization during the manufacturing of albumin and immunoglobulins from human plasma

Viral safety is a prerequisite for manufacturing clinical albumin and immunoglobulins from human plasma pools. This study was designed to evaluate the efficacy of cold ethanol fractionation and pasteurization (60°C heat treatment for 10 h) for the removal inactivation of human immunodeficiency virus type 1 (HIV-1) during the manufacturing of albumin and immunoglobulins. Samples from the relevant stages of the production process were spiked with HIV-1, and the amount of virus in each fraction was quantified by the 50% tissue culture infectious dose (TCID₅₀). Both fraction IV fractionation and pasteurization steps during albumin processing were robust and effective in inactivating HIV-1, titers of which were reduced from an initial 8.5 log₁₀ TCID₅₀ to undetectable levels. The log reduction factors achieved were ≥4.5 and ≥6.5, respectively. In addition, fraction III fractionation and pasteurization during immunoglobulins processing were robust and effective in eliminating HIV-1. HIV-1 titers were reduced from an initial 7.3 log₁₀ TCID₅₀ to undetectable levels. The log reduction factors achieved in this case were ≥4.9 and ≥5.3, respectively. These results indicate that the process investigated for the production of albumin and immunoglobulins have sufficient HIV-1 reducing capacity to achieve a high margin of safety.     

Firewood collected after a catastrophic wind event: the bark beetle (Scolytinae) and woodborer (Buprestidae,Cerambycidae) community present over a 3‐year period

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Functional and physical competition between phospholamban and its mutants provides insight into the molecular mechanism of gene therapy for heart failure

We have used functional co-reconstitution of purified sarcoplasmic reticulum (SR) Ca²⁺-ATPase (SERCA) with phospholamban (PLB), its inhibitor in the heart, to test the hypothesis that loss-of-function (LOF) PLB mutants (PLB_M) can compete with wild-type PLB (PLB_W) to relieve SERCA inhibition. Co-reconstitution at varying PLB-to-SERCA ratios was conducted using synthetic PLB_W, gain-of-function mutant I40A, or LOF mutants S16E (phosphorylation mimic) or L31A. Inhibitory potency was defined as the fractional increase in K_Ca, measured from the Ca²⁺-dependence of ATPase activity. At saturating PLB, the inhibitory potency of I40A was about three times that of PLB_W, while the potency of each of the LOF PLB_M was about one third that of PLB_W. However, there was no significant variation in the apparent SERCA affinity for these four PLB variants. When SERCA was co-reconstituted with mixtures of PLB_W and LOF PLB_M, inhibitory potency was reduced relative to that of PLB_W alone. Furthermore, FRET between donor-labeled SERCA and acceptor-labeled PLB_W was decreased by both (unlabeled) LOF PLB_M. These results show that LOF PLB_M can compete both physically and functionally with PLB_W, provide a rational explanation for the partial success of S16E-based gene therapy in animal models of heart failure, and establish a powerful platform for designing and testing more effective PLB_M targeted for gene therapy of heart failure in humans.