Determination of the cellulose and lignin content on wood fibre surfaces of eucalypts as a function of genotype and site

We compared the chemical composition of wood fibres and fibre surfaces of several eucalypt species and hybrids originating from various growth sites in South Africa. The objective was to test for differences in chemical surface composition due to genetics or site with the ultimate aim to facilitate a tailor-made supply of wood for pulping that results in an optimal blend of fibres that can be pulped together with similar yields. This, however, requires a sound knowledge of the fibre properties. The surface functionality on the single fibre level is a key property, because it determines how good inter-fibre bonding will be when paper is formed, which depends amongst other fibre properties on the amount of free hydroxyl groups that are available and therefore on the cellulose content on the fibre surface. The cellulose and lignin content on the fibre surface were determined with chemical force microscopy, a variation of atomic force microscopy. Since the general bulk composition of the fibre and the surface composition might differ, both parameters were determined. We found significant differences in the cellulose and lignin content on fibre surfaces, with regard to genotype and site, respectively. In some, but not all, cases, the surface composition of wood fibres followed the bulk composition, and differences were generally more pronounced. Differences due to genotype were significant, especially with regard to the surface lignin content—but variation due to site was also distinctly recognisable. This variation in surface functionality could be the reason why some pulpwood blends result in a lower pulp yield and different quality.     

韩国新村运动中的文化建设经验及启示

韩国在20世纪60年代组织实施的“新村运动”中,农村文化建设取得了巨大成功。文章总结了韩国新村运动中的文化建设经验：充分发挥政府的职能;重视农民的“精神启蒙”;注重农民的教育培训;注重村容环境的改观;政府给予财政支持等。指出中国当前在新农村文化建设中应该落实政府责任,发挥政府主导作用;重视农民教育,培养新型农民;创新农村人文生态环境,打造新村镇。     

Towards an acoustic‐based coupled observation and modelling system for monitoring and predicting ecosystem dynamics of the open ocean

Assessment of open‐ocean ecosystems relies on understanding ecosystem dynamics, and development of end‐to‐end ecosystem models represents an approach that addresses these challenges. These models incorporate the population structure and dynamics of marine organisms at all trophic levels. Satellite remote sensing of ocean colour and direct at‐sea measurements provide information on the lower trophic levels of the models, and fisheries studies provide information on top predator species. However, these models suffer from a lack of observations for the so‐called mid‐trophic levels, which are poorly sampled by conventional methods. This restricts further development, and we argue that acoustic observations from a range of platforms (e.g. buoys, moorings) can be linked to the ecosystem models to provide much‐needed information on these trophic levels. To achieve this, the models need to be tailored to incorporate the available acoustic data, and the link from acoustic backscatter to biologically relevant variables (biomass, carbon, etc.) needs attention. Methods to progress this issue are proposed, including the development of observation models and focal areas for ground truthing. To ensure full use of the potential of acoustic techniques, we argue that a systematic and long‐term strategy incorporating the following elements is required: development of metadata standards and automated data analysis, inclusion of acoustic sensors in large‐scale observatory programmes, improvement of observation‐model links, and efficient sampling strategies. Finally, these elements should be tied together in an observation‐modelling framework, coordinated by international organizations, to improve our understanding and quantification of open‐ocean ecosystem dynamics.     

玉米纹枯病菌细胞核纯化与原生质体转化的探讨

 引起玉米纹枯病的立枯丝核菌(Rhizoctonia solani Kühn)多为多核杂核真菌,也难以通过有性态使其细胞核进行单一化。利用原生质体再生的方法对单核玉米纹枯病菌JN的细胞核进行同核纯化,比较从单个原生质体再生菌获得的rDNA\|ITS序列,发现序列间存在差异,说明其细胞核没有达到预期纯化的效果。继而扩增了双核和多核玉米纹枯病菌的rDNA\|ITS序列,发现它们自身的rDNA\|ITS序列也存在差异,因此认为立枯丝核菌的这种rDNA\|ITS序列的差异可能是长期未经过有性阶段的结果且与其细胞核数目无关。使用转化丝状真菌的载体转化纹枯菌未获得稳定的转化子,进而对载体进行了改造,用纹枯菌(AG\|3)actin基因的启动子和终止子控制潮霉素基因构建了载体pRsA。利用PEG介导的原生质体转化方法,实现了对单核纹枯菌的转化,PCR验证得到3个转化子。但在PDA培养基连续继代5代后,转化子的潮霉素抗性消失。结果对改进纹枯菌的转化方法有借鉴意义。     

Serial temperature monitoring and comparison of rectal and muscle temperatures in immobilized free-ranging black rhinoceros (Diceros bicornis)

Control of body temperature is critical to a successful anesthetic outcome, particularly during field immobilization of wild animals. Hyperthermia associated with exertion can lead to serious and potentially life-threatening complications such as organ damage (including myopathy) and death. Methods for monitoring core body temperature must accurately reflect the physiologic status of the animal in order for interventions to be effective. The goal of this preliminary study was to compare serial rectal and muscle temperatures in field-immobilized black rhinoceros (Diceros bicornis) and evaluate a possible association. Twenty-four free-ranging black rhinoceros were immobilized between February and March of 2010 in Ethosha National Park, Namibia. Pairwise comparisons showed a correlation of 0.73 (95% CI; 0.70-0.75) between rectal and muscle temperature measurements. Results from a multivariable model indicate that muscle temperature readings were, on average, 0.46 degrees C (95% CI; 0.36-0.57 degrees C) higher than rectal temperatures while adjusting for repeated measurements on the same rhinoceros, effect of duration of immobilization, and effect of ambient temperature on rhinoceroses' temperature readings. As immobilization time increased, muscle and rectal temperature values within an individual rhinoceros tended to equilibrate. The overall temperatures decreased by an average of 0.00059 degrees C/min (95% CI; -0.0047 to -0.0035 degrees C/min; P = 0.779). As the ambient temperature at time of immobilization increased by 1 degree C, the average rhinoceros temperature increased by 0.09 degrees C (95% CI; 0.06-0.11 degrees C, P < 0.0001). Higher body temperature creates a potential for cellular damage leading to complications that include myopathy. Methods for monitoring rectal, muscle, and ambient temperatures should be incorporated into anesthetic monitoring protocols for large ungulates, particularly under field conditions.     

Biostimulant effects of Bacillus strains on wheat from in vitro towards field conditions are modulated by nitrogen supply

Bacillus velezensis strains, belonging to plant growth‐promoting rhizobacteria (PGPR), are increasingly used as microbial biostimulant. However, their field application to winter wheat under temperate climate remains poorly documented. Therefore, three B. velezensis strains IT45, FZB24 and FZB42 were tested for their efficacy under these conditions. Two biological interaction systems were firstly developed under gnotobiotic and greenhouse conditions combined with sterile or non‐sterile soil, respectively, and finally assayed in the field during two years coupled with different N fertilization rates. Under gnotobiotic conditions, all three strains significantly increased root growth of 14 d‐old spring and winter wheat seedlings. In the greenhouse using non‐sterile soil, only FZB24 significantly increased root biomass of spring wheat (+31%). The three strains were able to improve nutrient uptake of the spring wheat grown in the greenhouse, particularly for the micronutrients Fe, Mn, Zn, and Cu, but the observed increases in nutrient uptake were dependent on the organs and the elements. The root biomass increases in inoculated plants coincided with lowered nutrient concentrations of P and K. In 2014, under field conditions and absence of any N fertilizer supply, FZB24 significantly increased grain yields by 983 kg ha^?1, or 14.9%, in relation to non‐inoculated controls. The three strains in the 2015 field trial failed to confirm the previous positive results, likely due to the low temperatures occurring during and after inoculations. The Zeleny sedimentation value, indicative of flour quality, was unaffected by the inoculants. The results are discussed in the perspective of bacterial application to wheat under temperate agricultural practices.     

Identification of the antigenic proteins of Cowdria ruminantium.

Immunoblotting of Cowdria ruminantium proteins with sheep or bovine antiserum identified 2 antigenically conserved proteins, one being an immunodominant 31 kDa and the other a minor 27 kDa protein. These proteins are present in the electrophoretic profiles of the Welgevonden, Ball 3 and Kwanyanga stocks and are recognized by sheep antiserum to the Welgevonden, Ball 3, Kwanyanga, Mali, Comoro, Breed, Germishuys, Kümm and Mara stocks and by bovine antiserum to the Welgevonden stock of C. ruminantium. The stocks did not reveal identical or unique antigenic properties which could explain differences in pathogenicity and cross-immunity observed amongst the various stocks of C. ruminantium.     

Experimental studies with Stronglyloides papillosus in goats

Unusual clinical and pathological observations in the field in goats and sheep suffering from Strongyloides papillosus infection prompted experimental work on this parasite. Goats were infected percutaneously with either single or multiple, low or high levels of S. papillosus. Young goats up to 12 months of age were found to be the most susceptible. Some animals, however, showed substantial resistance to infective doses. Clinical signs included transient diarrhoea, misshapen, elongated faecal pellets terminally, dehydration, anorexia, cachexia, gnashing of teeth, foaming at the mouth, anaemia and nervous signs such as ataxia, a wide-based stance, stupor and nystagmus. A 'pushing syndrome' was seen in 22% of the animals. The pathological changes are described and included enteritis, status spongiosus in the brain, hepatosis leading to rupture of the liver, nephrosis, pulmonary oedema, interstitial pneumonia and pneumonia. About 6% of the goats died acutely from fatal hepatic rupture. The development of an acquired immunity was determined. The immunity elicited an allergic skin reaction at the application site of larvae or injection sites of larval metabolites. This immunity, however, could be breached by large doses of larvae. The most profound clinicopathological changes induced by the parasites were an anaemia (most pronounced in the young goats) and hypophosphataemia. Trace element analyses provided evidence of Cu, Mn and possibly Se deficiencies in some goats.