Imaging of Norway spruce early somatic embryos with the ESEM,Cryo-SEM and laser scanning microscope

This article describes the surface structure of Norway spruce early somatic embryos (ESEs) as a typical culture with asynchronous development. The microstructure of extracellular matrix covering ESEs were observed using the environmental scanning electron microscope as a primary tool and using the scanning electron microscope with cryo attachment and laser electron microscope as a complementary tool allowing our results to be proven independently. The fresh samples were observed in conditions of the air environment of the environmental scanning electron microscope (ESEM) with the pressure from 550 Pa to 690 Pa and the low temperature of the sample from −18 °C to −22 °C. The samples were studied using two different types of detector to allow studying either the thin surface structure or material composition. The scanning electron microscope with cryo attachment was used for imaging frozen extracellular matrix microstructure with higher resolution. The combination of both electron microscopy methods was suitable for observation of “native” plant samples, allowing correct evaluation of our results, free of error and artifacts.     

Specific Proteins in the Indirect Somatic Embryogenesis of Freesia

Using the young inflorescence segments of Freesia refracta as explants, indirect somatic embryogenesis of somatic cells was induced in a N6 medium supplemented with some exogenous hormones. SDS-polyacrylamide gel electrophoresis（SDS-PAGE） was used for the analysis of soluble proteins produced during the somatic embryogenesis of this plant. There are six polypeptides, which might play some roles in the process of somatic embryo development. Tltree polypeptides（45, 53 and 55 kD） were detected in the stages of embryogenic callus, globular embryoid, and embryoid with coleoptiles, except the embryoid with leaf. One polypeptide（ 83 kD） was specific for the stages of embryoid with eoleoptiles and embryoid with leaf. One polypeptide（37 kD） was detected in the first two stages, namely, embryogenic callus and globular embryoid. One polypeptide（35 kD） was regularly synthesized in each stage, from embryogenic callus to embryoid with leaf.     

Specific Proteins in the Indirect Somatic Embryogenesis of Freesia Refracta

IntroductionHaberlandt[1]proposed the conception of plantso-matic embryo in 1902, which states that plant cellsexhibit totipotency; each cell could divide ceaselesslyand eventually develops into a mature plantlet. Allthese provide a theoretical evidence for somatic embryo-genesis. The related researches reveal thatplantembry-ogenesis occurs as a result of the selective expression ofsets of genes that allowthe synthesis of special proteinsin a temporal and spatial sequential manner under themut…     

Calibration of somatic cell count in milk based on near-infrared spectroscopy

A PLS model for prediction of somatic cell count (SCC) based on near-infrared (NIR) spectra of unhomogenized milk is presented in the study. Samples of raw milk were collected from cows in the early lactation period (from 7th to 29th day after parturition). The NIR spectra were measured in the region 400–1100 nm. As reference method a fluoro-opto-electronic method was applied. Different preprocessing methods were investigated. The robust version of PLS regression was applied to handle outliers present in the dataset and the uninformative variable elimination–partial least squares (UVE–PLS) method was used to eliminate uninformative variables. The final model is acceptable for prediction of SCC in raw milk.     

Toward understanding of the role of reversibility of phenotypic switching in the evolution of resistance to therapy

Reversibility of state transitions is intensively studied topic in many scientific disciplines over many years. In cell biology, it plays an important role in epigenetic variation of phenotypes, known as phenotypic plasticity. More interestingly, the cell state reversibility is probably crucial in the adaptation of population phenotypic heterogeneity to environmental fluctuations by evolving bet-hedging strategy, which might confer to cancer cells resistance to therapy. In this article, we propose a formalization of the evolution of highly reversible states in the environments of periodic variability. Two interrelated models of heterogeneous cell populations are proposed and their behavior is studied. The first model captures selection dynamics of the cell clones for the respective levels of phenotypic reversibility. The second model focuses on the interplay between reversibility and drug resistance in the particular case of cancer. Overall, our results show that the threshold dependencies are emergent features of the investigated model with eventual therapeutic relevance. Presented examples demonstrate importance of taking into account cell to cell heterogeneity within a system of clones with different reversibility quantified by appropriately chosen genetic and epigenetic entropy measures.     

人体指纹谱的初步分析

大量实验测试表明:人体正常指纹谱反映人体正常状态,而人体异常指纹谱则反映人体异常状态。本文对人体指纹谱的结构及其机理做了初步分析和讨论。     

牛奶体细胞数检测的研究进展

快速准确的牛奶体细胞数检测对于保证牛奶品质和监测奶牛健康具有重要意义。从牛奶体细胞数的基本概念、牛奶体细胞对牛奶的影响、国内外研究进程、牛奶体细胞数检测方法、相关检测仪器的发展等方面对牛奶体细胞数检测的研究进展进行了综述,分析了各种检测方法和检测仪器的优缺点,指出了作为热点方法之一的基于计算机视觉的牛奶体细胞数检测关键是体细胞图像分割与识别的准确性、识别速度以及相应自动化仪器的研制。     

Genome wide characterization of the SERK/SERL gene family in Phalaenopsis equestris,Dendrobium catenatum and Apostasia shenzhenica (Orchidaceae)

Somatic embryogenesis receptor kinases (SERKs) play a significant role in morphogenesis, stress/defense and signal transduction. In the present study, we have identified two SERK and 11 SERK-like (SERL) genes in Phalaenopsis equestris, two SERK and 11 SERL genes in Dendrobium catenatum, and one SERK and eight SERL genes in Apostasia shenzhenica genome. Characterization of the SERK proteins revealed the presence of a signal peptide, a leucine zipper, five leucine-rich repeats (LRRs), a serine proline proline (SPP) motif, a transmembrane region, a kinase domain, and a C-terminus. Most of the SERK/SERL proteins were characterized with similar physicochemical properties. The presence of transmembrane region predicted their membranous localization. Tertiary structure prediction of all the five identified SERK proteins had sequence identity with BAK1 protein of Arabidopsis thaliana. Generally, all the SERK/SERL genes shared similar gene architecture and intron phasing. Gene ontology analysis indicated the role of SERKs in receptor and ATP binding, signal transduction, and protein phosphorylation. Phylogenetic analysis revealed the clustering of SERKs and SERLs in distinct clades. Expression of SERKs in reproductive tissues like floral bud, floral stalk, whole flower and pollen was reported to be higher than their expression in vegetative tissues with an exception of PeSERK1 and DcSERK1 which showed higher expression in leaves and roots, respectively. Likewise, a higher expression of AsSERK1 was observed in tubers. However, lower expression of SERLs was observed in majority of tissues studied irrespective of their vegetative or reproductive origin. This work paves way for future studies involving functional characterization of SERK/SERLs and their potential role in embryogenesis/organogenesis as an aid to regeneration and multiplication of endangered orchids.     

Electrochemical determination of Ag-ions in environment waters and their action on plant embryos

We utilized liquid chromatography coupled with electrochemical detector (HPLC-ED) for analyzing of silver ions. The optimization of basic chromatographic parameters has been done. The detection limit (3 S/N) obtained were 20 nmol/dm(3). Influence of different interferences (anions and cations) on current response of silver ions has been described. Moreover, we used HPLC-ED to analyze waters of different purity including photographic emulsion, which naturally contained silver ions. We found out that content of silver ions in the emulsion was 1.57 x 0.03 mmol/dm(3). Moreover, we investigated influence of silver ions on early somatic embryos of Blue Spruce. We were interested in the issue how much silver ions can embryos uptake during four days long treatment. For this purpose, we used optimized HPLC-ED technique. The content increased with increasing treatment time and applied concentration. We also studied how silver ions can influence thiols content in the treated embryos. For these purposes we used adsorptive transfer stripping voltammetry in connection with differential pulse voltammetry--Brdicka reaction. It clearly follows from the obtained results that content of thiols increased with increasing treatment time and applied concentration.