Chorionic villus sampling: Improved method for preparation of karyotypes after short-term incubation

A method for the isolation and trypsin-Giemsa banding of metaphases obtained after short-term incubation (48 h) of cytotrophoblast cells from chorionic villus sample is described. A new slide-making instrument, developed expressly to enhance the spreading of chromosomes from metaphases released from small tissue pieces, is responsible for the increase yield of analysable metaphases in this protocol.     

Prenatal diagnosis of pericentric inversion of chromosome no. 17 in a twin pregnancy

Although prenatal genetic diagnosis can usually provide prospective parents with information as to whether their fetus is affected with certain genetic conditions, the presence of twins and the uncertainty about the phenotype of some chromosome variations pose a major dilemma and make genetic counselling very difficult. Here, a case report of an unusual chromosome aberration (pericentric inversion of chromosome no. 17) in a twin pregnancy which was originally suspected to be monoamniotic but later proved to have two sacs was presented.     

Transformation of Organic Matter of the Larch Forest Soils in the Northern Taiga of Nizhne-Tungusskoe Plateau, Central Siberia

The evaluation of biospheric role of the boreal forests in the accumulation of carbon is connected with the evaluation of organic matter (OM) pool in soils. The research sites were larch forests, they are situated on Nizhne-Tungusskoe Plateau. Larch forests of feather-moss and lichen types (110 and 380 years old) were formed on 'ochric podbur' soils. Litter stocks are 3.5–4.5 kg m^{− 2} with thickness 10–25 cm. Cryomezomorphic northern taiga soils contains 38–73 t (carbon) ha^{− 1}. Pool of fast mineralized OM has average value 38.1 t (carbon) ha^{− 1}, including 20.5 and 6.4 t (Carbon) ha^{− 1} of labile compounds on surface and in the soil, and 11.2 t (carbon) ha^{− 1} of mobile OM. Microbial mass reaches 1.78–3.47 t (carbon) ha^{− 1}, its proportion is 3.6–4.9% of the total OM carbon. Zoomass of feather-moss larch forest is 0.20–0.61 * 10^{− 2}, in lichen larch forest −0.01–0.07 * 10^{− 2} t (carbon) ha^{− 1}. A pool of resistant to biological decomposition and bonded to mineral soil matrix OM is 17.7 t (carbon) ha^{− 1} and it varies from 18.6 to 29.0 in feather-moss larch forest, and from 6.4 to 17.0 t (carbon) ha^{− 1} in lichen larch forest. Two-years field experiment has been performed to determine transformation rates of various plant litter fractions and to clarify the role of soil biota in these processes. The results showed participation of all biota groups in the decomposition of plant residues caused weight loss of larch-needles and root mortmass. Isolation of organic matter from all-size invertebrate groups leads to some decrease of decomposition activity.     

巴西圣保罗州莫日-瓜苏河流流域中的汞:根据210Pb测年剖面估计的沿海泻湖与河流贡献之间的联系

引言 莫日-瓜苏河位于纳斯吉拉斯州,海拔高1450m.流淌470km后,该河流注入圣保罗州的帕尔杜河.其流域总面积为1400km2,其中有86%位于圣保罗州,包括一个工业化地区[1].