Changes in nucleus, nucleolus and cell size accompanying somatic embryogenesis of Theobroma cacao L. II. Relation between basic protein content and size of nucleus, nucleolus and cell

Embryo formation from callus of Theobroma cacao L. was associated with the changes in relationship between nuclear, nucleolar and cell sizes and the content of basic proteins (FG-FCF-stained). Together with the increase in nuclear size of callus and proembryo cells the increase in the amount of nuclear basic proteins was found. In the callus cells the increase in nucleolar protein content exceeded that in nucleolus size, which led to the rise in basic protein concentration in the nucleolus. However, in the early stage of embryogenesis the increase in protein content was not so marked as that in callus, which indicated that embryogenesis involved a decrease in concentration of nucleolar basic proteins. Differences between callus and proembryo cells were also observed in the concentration of cytoplasmic proteins. The increase in size of callus cells was the same as the increasing amount of cytoplasmic proteins. In proembryos a significant increase in cell size was accompanied by only slight changes in cytoplasmic proteins. The stimulation of embryogenesis by 2,4-D resulted in an increase of nuclear concentration of basic proteins in proembryos. The intensification of embryogenesis involved the decrease of the concentration of nucleolar proteins together with the increase in concentration of basic cytoplasmic proteins.     

Changes in nucleus, nucleolus and cell size accompanying somatic embryogenesis of Theobroma cacao L. I. Relationship between DNA and total protein content and size of nucleus, nucleolus and cell

There was a linear relation between an increase in DNA content and size of nuclei, nucleoli and cells in callus and proembryos (Theobroma cacao L.). In callus the increase of DNA content was accompanied by proportional increase in nuclear size whereas in proembryos the increase in nuclear size did not match the increasing amount of DNA. The stimulation of embryogenesis by 10(-2) mg/l 2,4-D was associated with increase in nuclear and nucleolar size and with decrease in cell sizes. Inhibition of embryogenesis by 1.0 mg/l 2,4-D+10% coconut water did not change nuclear size, but increased cell size in relation to the control. The process of embryo formation was accompanied by changes in relationship between nuclear, nucleolar and cell size and the total (DNFB-stained) proteins content. In callus as well as in proembryo the increase in total protein content in nucleus was not equivalent to the increasing sizes of nuclei which leads to the decrease in nuclear protein concentration. Similar situation was observed for nucleoli. Differences were found in the concentration of cytoplasmic proteins between the callus and proembryo cells. The stimulation of embryogenesis by low concentration of 2,4-D resulted in decrease in concentration of total proteins in nuclei and nucleoli and the increase in cytoplasm.     

The Properties of Water in the Pressure–Temperature Landscape

Water represents the major component of most food systems. During thermal or high-pressure processing, physical and chemical properties of water are changed. The p–T diagram represents an obvious presentation of isoproperty lines and their pressure and temperature dependencies. In this work, 15 different properties of pure water are shown as isoproperty lines in the pressure–temperature landscape. By using functional relationships from the “International Association for the Properties of Water and Steam” and databases from the “National Institute of Standards and Technology,” highest accuracy is guaranteed. Applying the generated graphs, a compact overview is given and a wide range of thermal and high-pressure processes can easily be compared. The different pressure and temperature dependencies of all properties showed the complexity of medium conditions during thermal and high-pressure processing. An extended understanding of pressure–temperature dependencies will improve process concepts as well as industrial applications at high temperature and high isostatic pressure.     

Sucrose-mediated regulation of fatty acid composition in asexual embryos of Theobroma cacao

Asexual embryos of Theobroma cacao L. cultured in vitro grew to a size and fresh weight equal to mature zygotic embryos in vivo when cultured in liquid medium on a rollodrum apparatus. Changes in the fatty acid composition in the asexual embryos, similar to those which occur in the zygotic embryo during normal maturation, were stimulated as the sucrose concentration in the medium was increased to an optimum at 27% sucrose (w/v). As the sucrose concentration increased, there was a shift in the fatty acid composition from predominantly polyunsaturated to saturated and monounsaturated fatty acids characterized by an increase in the mole percents of stearic (18:0) and oleic (18:1) acids and a decrease in the mole percents of linoleic (18:2) and linolenic acids (18:3).     

The replication of Hyposoter didymator polydnavirus: Cytopathology of the calyx cells in the parasitoid

Summary— In the ichneumonid wasp Hyposoter didymator, a polydnavirus was detected in the female reproductive tract. With the aim of studying the regulation of polydnavirus replication, the location and the structure of the virus-producing cells were determined, and the virus replication process was followed inside the ovaries of young adult females observed in light and electron microscopy. The examination of ovaries of pupa females revealed that virus replication is initiated within the calyx just prior to adult emergence. This study revealed that the calyx appears to be a specialized virogenic tissue which also has, during late pupal life, a secretory function that alters the function of virus production.