NMR characterization for polysaccharide moiety of a glycopeptide

Ganoderma lucidum is a traditional medicinal herb used to treat various diseases in China and Southeast Asia for thousands of years. An aqueous glycopeptide, LZ-B-1, was prepared by successive chromatography and exhibited an immunostimulating potential. To better understand the mechanism of bioactivity for this compound, the polysaccharide moiety of glycopeptide LZ-B-1 was studied by NMR spectroscopy. The results indicated that the polysaccharide moiety had a backbone of 1,6-disubstituted-α-galactopyranosyl, 1,2,6-trisubstituted-α-galactopyranosyl, 1,3-disubstituted-β-glucopyranosyl and 1,4,6-trisubstituted-β-glucopyranosyl residues. The branches were mainly composed of 1-substituted-β-glucopyranosyl and 1-substituted-α-fucopyranosyl residues.     

Structural characterization and radioprotection of bone marrow hematopoiesis of two novel polysaccharides from the root of Angelica sinensis (Oliv.) Diels

Two novel homogeneous polysaccharides, APS-1a and APS-3a were successfully isolated from the root of Angelica sinensis. APS-1a was composed of galactose, arabinose and glucose in a relatively molar percentage of 57.34%, 27.67% and 14.98%, and had a molecular weight of 49.0 kDa, whereas APS-3a was composed of galactose, arabinose and glucose in a relatively molar percentage of 84.54%, 6.50%, and 8.96%, and had a molecular weight of 65.4 kDa. APS-1a and APS-3a mainly consisted of 1,4-linked galactose, 1,3,6-linked galactose, T-galactose and T-arabinose, and the molar ratio of each linkage was different between APS-1a and APS-3a. The bioactivity analysis showed that APS-1a and APS-3a increased the thymus and spleen index, the number of red blood cell (RBC) and white blood cell (WBC) in peripheral blood and the cellularity of bone marrow cell numbers in irradiated mice, protected mice against radiation-induced micronucleus formation in bone marrow, suggesting that polysaccharides could be used as radioprotective agents, especially for promoting bone marrow hematopoiesis.     

淡紫拟青霉T-DNA插入突变体的表型分析

研究淡紫拟青霉T-DNA插入突变体,鉴定突变体的表型特征,为淡紫拟青霉致病机制分析及致病相关的基因克隆奠定基础。PCR检测筛选的14株T-DNA插入突变体,观察和测定菌落形态,菌落生长速率,产孢量,孢子萌发率和菌丝干质量等生物学性状,并比较突变体致病力。结果表明突变体均含有beta-tubulin基因序列,T-DNA已整合进入野生型菌株20-7的基因组中。通过与野生型菌株对比,发现突变体菌落形态发生了不同程度的改变。菌落生长速率明显增大的菌株占全部菌株的85.71%,只有BN-11菌株的菌落生长速率降低。产孢量显著变大的菌株有BN-11和BN-12,为菌株总数的14.29%。孢子萌发率发生改变的菌株占78.57%。菌丝干质量发生明显增大和减少的菌株都占全部突变体的21.43%。筛选获得了1株致病力增强的突变体BN-11和11株致病力显著降低的突变体。     

Habitat assessment for forest dwelling species using LiDAR remote sensing: Capercaillie in the Alps

Large-scale information on habitat suitability is indispensable for planning management actions to further endangered species with large-spatial requirements. So far, remote sensing based habitat variables mostly included environmental and land cover data derived from passive sensors, but lacked information on vegetation structure. This is a serious constraint for the management of endangered species with specific structural requirements. Light detection and ranging (LiDAR), in contrast to passive remote sensing techniques, may bridge this gap in structural information at the landscape scale. We investigated the potential of LiDAR data to quantify habitat suitability for capercaillie (Tetrao urogallus), an endangered forest grouse in Central Europe, in a forest reserve of 17.7 km². We used continuous variables of horizontal and vertical stand structure from first and last pulse LiDAR data and presence–absence information from field work to model habitat suitability with generalized linear models (GLM). The two final habitat suitability models explained the observed presence–absence pattern moderately well (AUC of 0.71 and 0.77) with horizontal structure explaining better than vertical structure. Relative tree canopy cover was the most important variable with intermediate values indicating highest habitat suitability. As such, LiDAR allowed us to translate the results from habitat modeling at the landscape scale to effective management recommendations at the local scale at a level of detail that hitherto was unavailable for large areas. LiDAR thus enabled us to integrate individual habitat preferences at the scale of entire populations and thus offers great potential for effective habitat monitoring and management of endangered species.     

Roles of seed and pollen dispersal in natural regeneration of Castanopsis fargesii (Fagaceae): Implications for forest management

Natural regeneration is an important process to reverse the loss of forests. Understanding the process of natural regeneration is crucial for achieving sustainable forest management. In this study, we examined the effects of seed and pollen dispersal in naturally regenerated populations of Castanopsis fargesii. Genetic variation in six populations along two successional series (three successional stages in each series: early, pre-climax, and climax) was assayed using RAPD (random amplified polymorphic DNA) markers. High genetic variability was observed as measured with Shannon's information index. A majority of genetic variation was distributed within populations (Φ_st = 0.1271) and significant isolation by distance existed among populations. A contrasting pattern of genetic variation along these two series was observed, representing different scenarios of natural regeneration processes. The ratio of the number of migrants between the mature populations to the number of migrants from the mature to immature populations was estimated as 1.146 ± 0.099 to 1.981 ± 0.164, implying that comparable seed and pollen dispersal might exist at a fine spatial scale (∼2 km²). The results suggest the critical role of seed dispersal in shaping genetic composition and diversity in the second-growth forests. Barriers to seed dispersal from a variety of genetic sources could result in low genetic diversity in naturally regenerated populations. Management that facilitates the connectivity of newly regenerated stands with mature forests could be effective for natural regeneration given the predominant role of short-distance dispersal of seeds in this species.     

Management strategies for a large-scale mountain pine beetle outbreak: Modelling impacts on American martens

We assessed the effectiveness of alternative forest management strategies for maintaining American martens (Martes americana) in a sub-boreal landscape subject to an extensive mountain pine beetle (Dendroctonus ponderosae) outbreak, associated salvage logging, and climate change in north-central British Columbia, Canada. We structured the analysis in a Bayesian network (BN) meta-model that incorporated the results of spatially explicit modelling of landscape conditions (natural and logging disturbance, habitat quality, number of potential territories, and connectedness of territories) with analytical population modelling. The BN meta-model was then used to examine habitat and population size responses (adult females only are presented) to management scenarios, in the context of uncertainty of model parameters, management objectives, and climate change. Status quo management is dominantly clear-cutting with 3–20% of each harvest unit retained as mature patches, with reforestation by planting in the remainder. Management options we examined were: (1) the status quo, (2) varying the total annual timber harvest on the landscape (100%, 80% or 50% of current long-term sustained yield estimates), (3) the protection of understory trees during logging, and (4) 30–70% retention of overstory (partial cutting in distinct patches <1 ha in size) in each harvest unit, for 33% or 50% of the annual timber harvest. We found that marten habitat and population size declined substantively with the beetle outbreak and associated salvage cutting. The choice of management strategy then had a long-term effect on the potential for marten recovery after the beetle outbreak. Partial cutting scenarios had the greatest average long-term marten population levels, followed in order by reduced harvest rates, understory protection, and the status quo. Management scenarios with the best chance of meeting conservation goals without over-protecting habitat (and thus unnecessarily constraining timber management) varied with the population objective chosen. The choice of management strategy will depend on the weighting of marten outcomes against the economic desirability of timber harvest strategies, willingness to gamble on climate change, and the time-frame of interest.