The role of common starlings (Sturnus vulgaris) in the epidemiology of bacterial, potentially human pathogenic, disease agents

Since a long time a public garden in Basel is known as a site for overnight accommodation and assembly of starlings. The birds cause an immense faecal contamination of the park and the neighbouring district. A nursery and a primary school are directly affected. To evaluate the health risk coming from the starlings droppings for the population, particularly for the children and to assess the role of starlings in the transmission of diseases to humans and in the epidemiology of human diseases the presence of human bacterial pathogens in the faeces of starlings was determined. Some of the isolated strains were further typed and compared to strains of human origin. C. jejuni, L. monocytogenes and C. psittaci were most often found. The typing of some C. jejuni and L. monocytogenes isolates showed a great variety of geno-, sero- respectively phage types that did not belong to the strains most often found in isolates of human origin. Starlings can harbour human pathogens and therefore a potential risk of infection comes from their droppings. It seems however rather improbable, that these birds present a constant direct source of infection for human beings.     

Impact of sugarcane yellow leaf virus (ScYLV) on the carbohydrate status of sugarcane: Comparison of virus-free plants with symptomatic and asymptomatic virus-infected plants

The carbohydrate concentration of old and young sugarcane plants, either virus-free or infected by sugarcane yellow leaf virus, was compared. Internode lengths and fresh weights of symptomatic plants were reduced, but not the sucrose concentrations. Starch and sucrose concentration in green leaf tops of mature (18 months old) was the highest in asymptomatic plants followed by symptomatic, and then by virus-free plants. Carbohydrates increased during daytime by 5–20%. The carbohydrate concentration in leaves of young, 6 months old plants was much lower than in mature plants and it increased to 500% during daytime. Asymptomatic leaves had a higher level of carbohydrates, especially starch, from late afternoon until the end of the night, suggesting a reduction of assimilate export.     

落叶松不同类型胚性和非胚性愈伤落叶松不同类型胚性和非胚性愈伤

以华北落叶松继代、增殖培养的不同类型的胚性及非胚性愈伤组织为材料，测定其氨基酸、糖类、酚酸、激素以及离子的含量，结果表明氨基酸含量的差异十分明显，质地硬的非胚性愈伤组织中18种游离氨基酸含量为胚性愈伤组织的2倍以上，经ABA处理后，胚性愈伤组织中多糖及邻苯二酚含量急剧升高；三糖含量与不同基因型密切相关；乙烯释放量在非胚性愈伤组织中高于胚性愈伤组织；金属离子CO     

落叶松胚性愈伤组织诱导培养基中激素的311-A最优回归设计筛选

采用311-A最优回归设计，对落叶松胚性细胞诱导中激素种类与浓度优化筛选，建立胚性愈伤组织量依2，4-D、BA、KT的多基本原则 式回归方程，分析了试验因子的主效应和互作效应，借助此方程获得了3因子的最佳配比组合以及最佳胚性愈伤组织发和亘，2，4-D为1.29mg.L^-1、BA为0.39mg.L^-1和KT为0.58mg.L^-1时，落叶松胚性愈伤组织的诱导量可达到13.9317mg.个^-1(外植体）。结果表明，这是一种简便、实用、科学的优化培养基的途径。     

Materials with negative compressibilities in one or more dimensions

Rare crystal phases that expand in one or more dimensions when hydrostatically compressed are identified and shown to have negative Poisson's ratios. Some of these crystals (i) decrease volume and expand in two dimensions when stretched in a particular direction and (ii) increase surface area when hydrostatically compressed. Possible mechanisms for achieving such negative linear and area compressibilities are described for single crystals and composites, and sensor applications are proposed. Materials with these properties may be used to fabricate porous solids that either expand in all directions when hydrostatically compressed with a penetrating fluid or behave as if they are incompressible.     

Effect of crop growth on the distribution and mineralization of soil sulfur fractions in the rhizosphere

The effect of plant growth on the mineralization of organic matter and distribution of soil S fractions (plant available SO₄^2—, adsorbed SO₄^2—, carbon‐bonded S, ester‐bonded S, and residual‐S) in the rhizosphere was studied in a greenhouse experiment using a rhizobag technique. In this study wheat, oilseed rape and radish were grown on two soils, a Haplic Acrisol and a Hortic Anthrosol. Significant differences between S fractions in the rhizosphere and non‐rhizosphere were determined in dependence on soil type and crop species. In all cropped treatments lower amounts of ester‐bonded S and higher levels of residual‐S were found in the rhizosphere than in the non‐rhizosphere, while the amount of carbon‐bonded S fractions was similar. These results indicate firstly, that the arylsulfatase activity was higher in the rhizosphere than in the non‐rhizosphere and secondly, that mass flow of SO₄^2—‐S to the rhizosphere increased after mineralization of residual‐S. Compared to the non‐vegetated soil, the ester‐bonded S fraction of wheat and oilseed rape decreased in the rhizosphere revealing that the mineralization of organic S in the rhizosphere is related to the crop type.     

Untersuchungen über die Wirksamkeit des DDT-Präparates Duolit auf Landlungenschnecken

Ohne Zusammenfassung     

Quantitative Untersuchungen über den Schadfraß von Schnecken an Gartenerzeugnissen

Ohne Zusammenfassung     

The effect of some cryoprotectants on dromedary camel frozen‐thawed semen

The cryopreserved camel semen is often associated with poor quality and fertility. This study aimed to improve the dromedary frozen semen quality by comparing the efficiency of four cryoprotectant agents (CPAs) on sperm freezability. Semen samples were collected from seven male Maghrabi camels, diluted with Shotor diluent supplemented with glycerol (Sh‐G), dimethyl formamide (DMF, Sh‐DF), dimethyl sulfoxide (DMSO, Sh‐DS) or ethylene glycol (EG, Sh‐EG), all at 6% final concentration, and the samples were subjected to cryopreservation. The results revealed the superiority of Sh‐DF over Sh‐G and Sh‐DS in terms of post‐thaw motility (55.83 ± 2.20 vs. 47.50 ± 4.33 and 45.00 ± 2.89%, respectively), sperm membrane (49.00 ± 0.58, 39.33 ± 3.33 and 42.67 ± 1.45%, respectively) and acrosomal integrities (53.00 ± 0.58, 57.33 ± 0.88 and 52.33 ± 1.45%, respectively). Sh‐EG group showed the lowest post‐thaw motility, plasma membrane and acrosome integrities (12.50 ± 1.44, 22.67 ± 1.45 and 30.67 ± 1.45, respectively). In conclusion, the protocols of dromedary camel semen cryopreservation could be enhanced using 6% DMF as a cryoprotectant agent.