FGF signaling is essential for the early events in the development of the chick nervous system and mesoderm.

Fibroblast growth factor (FGF) belongs to a family of polypeptides with diverse biological functions. In the present study we have assessed the role of FGF signaling in the development of nervous system and mesodermal tissues in chick embryo. Treatment of in vitro cultured embryos with exogenous, human recombinant FGF led to abnormalities in neural induction and development, notochord formation and somitogenesis as studied by gross morphology and histology. Overall growth and development was also adversely affected as seen from the measurement of body axis length. Further, treatment of embryos with FGF resulted in differential modulation of expression of two genes important in normal development as studied by whole mount in situ hybridization using DIG-labeled riboprobes. The expression of Brachyury, which is necessary for mesoderm formation, was down-regulated in FGF-treated embryos. The expression of noggin, the product which participates in the patterning of the chick neural tube was, on the other hand, up-regulated within 2 h. We also studied development of neural and mesodermal tissues in conditions where FGF signaling was defective. This was achieved by culturing the embryos in the presence of suramin. In the presence of low doses of suramin (100-150 nmole/culture), abnormalities were detected mainly in the mesodermal structures while at higher doses (200-400 nmole/culture), the nervous system too was found to be abnormal in a large proportion of embryos. Treatment of chick embryos with suramin (200 nmole/culture) also modulated the expression of Brachyuryand noggin within a 2 h period. The results showthat FGF signaling plays an important role in the molecular events leading to the development of nervous system and mesodermal tissues in the chick embryo.     

Vegetal cover estimated by digital photographs related to biomass in a grassland site in northern Mexico

A regression model was used to determine the relationship between aerial herbaceous biomass and vegetation coverage estimated by digital images. Four samplings (n=36 each date) of vegetation cover and herbaceous biomass were performed during the growing season in 2011 in a grassland dominated by Bouteloua gracilis in La Cieneguilla, Municipality of Villa Hidalgo, Durango. Average production of dry biomass was 37.36 ± 9.66 g/m², and mean vegetation cover 30.02%. Dry biomass data were tested for normality using the test of Kolmogorov Smirnov, finding a lack of fit. The data were subjected to a logarithmic transformation and the model Ln(y) = 1.637926 + 0.08501X - 0.000586X² with an adjusted R² = 0.89 was found. In order to validate this model, another five samplings were carried out in 2013 at the same site during summer and autumn, using the same sampling size for each date as in 2011. Data collected in 2013 were analyzed with the model Ln (y) = β₀ + β₁X + β₂X². A comparison of regression coefficients was carried out between the 2011 and 2013 models with t (180+144-9-11-2=302, p<0.05) = 1.967. The results indicated that it is possible to use the 2011 regression model to estimate herbaceous aerial biomass from vegetation cover measurements with aerial photographs in La Cieneguilla site during summer and fall.     

A new species of Parapanteles Ashmead, 1900 (Hymenoptera: Braconidae: Microgastrinae) parasitic on Charaxes athamas (Drury) (Lepidoptera: Nymphalidae) in India

A new species of gregarious endoparasitoid, Parapanteles athamasae n. sp. (Hymenoptera: Braconidae), parasitising caterpillars of Charaxes athamas (Drury) (Lepidoptera: Nymphalidae) on the host plant Senegalia catechu (=Acacia catechu) (L.f.) Hurter & Mabb., is described from Maharashtra, India. Diagnostic characters of the new species include: propodeum with areola 0.93× longer than wide, legs yellow, hind tibia 4.30× as long as ovipositor, ovipositor sheaths exerted, first metasomal tergal plate 1.24× longer than wide, with coarse sculpture merging with longitudinal striations at 3/4 of the apical region. This is the first time a species of the family Nymphalidae Rafinesque is recorded in association with Parapanteles Ashmead, 1900. A key to the Indian species of Parapanteles based on females is also provided.     

小波能量评价EEG的不同成分对癫痫发作预报的价值

癫痫是一种严重危害人类健康的常见疾病,对癫痫发作进行预报具有重要的重要意义。通过对3例部分性继发全身性发作的癫痫病人在发作最长约30min的8导EEG进行小波分解,将EEG中的棘波、尖波成分与慢波成分分别突出到不同的尺度上,并计算相应尺度上这些成分的能量,考察这些不同成分在发作前的变化趋势。发现在发作前的若干分钟,8导EEG的慢波能量都有显著增大,而与棘波／尖波有关的快波能量基本上没有什么变化趋势,说明EEG慢波成分的增大对部分性继发全身性发作的预报具有重要价值,EEG的“慢波过大”可能是癫痫从发作间状态转变为发作的重要因素。     

Uniform band intensities in fluorescent dye terminator sequencing.

The use of Cyanine dye (Cy5 and Cy5.5) labeled dideoxy terminators with Thermo Sequenase DNA polymerase in DNA sequencing provides uniform band intensity, improved sequence read-length, and accuracy. It also greatly improves the ability to detect single base heterozygotes with dye-terminator sequencing method.