Boron deficiency alters cytosolic Ca2+ concentration and affects the cell wall components of pollen tubes in Malus domestica.

Boron (B) is essential for normal plant growth, including pollen tube growth. B deficiency influences various physiological and metabolic processes in plants. However, the underlying mechanism of B deficiency in pollen tube growth is not sufficiently understood. In the present research, the influence of B deficiency on apple (Malus domestica) pollen tube growth was studied and the possible regulatory mechanism evaluated. Apple pollen grains were cultured under different concentrations of B. Scanning ion-selective electrode technique, fluorescence labelling and Fourier-transform infrared (FTIR) analysis were used to detect calcium ion flux, cytosolic Ca2+ concentration ([Ca2+ ]cyt), actin filaments and cell wall components of pollen tubes. B deficiency inhibited apple pollen germination and induced retardation of tube growth. B deficiency increased extracellular Ca2+ influx and thus led to increased [Ca2+ ]cyt in the pollen tube tip. In addition, B deficiency modified actin filament arrangement at the pollen tube apex. B deficiency also altered the deposition of pollen tube wall components. Clear differences were not observed in the distribution patterns of cellulose and callose between control and B deficiency treated pollen tubes. However, B deficiency affected distribution patterns of pectin and arabinogalactan proteins (AGP). Clear ring-like signals of pectins and AGP on control pollen tubes varied according to B deficiency. B deficiency further decreased acid pectins, esterified pectins and AGP content at the tip of the pollen tube, which were supported by changes in chemical composition of the tube walls. B appears to have an active role in pollen tube growth by affecting [Ca2+ ]cyt, actin filament assembly and pectin and AGP deposition in the pollen tube. These findings provide valuable information that enhances our current understanding of the mechanism regulating pollen tube growth.

PKR2 and ß-catenin genes regulates pancreatic cancer chemosensitivity.

OBJECTIVE: Pancreas is a well developed glandular organ lying behind the stomach. Cancer arises in this organ are difficult to identify in the initial stages, even in advanced stages it shows non-specific symptoms, and it is difficult to prognosis. Since they are identified and treated in the last stage, they are less responsive to chemotherapy. Therefore, it is important to study the proteins that are involved in regulating chemosensitivity and chemoresistance. MATERIALS AND METHODS: Initially, using KRAS mutant mice, we developed initial and advanced stage of pancreatic cancer. And we analyzed the expression of PKR2 and ß-catenin in different pathological stages of pancreatic cancer using Immunohistology and Western blotting. RESULTS: The histology of the tissue nature confirms and helps to categorize cancer, which shows enlarged nucleus in initial stages and shows clustering of cells in advanced stages. Immunohistological and Western blotting analyzes show prominent increasing in the expression of PKR2 and ß-catenin as the tumor develops to the next stages. On the course of initial treatment with cisplatin we find out that PKR2 and ß-catenin regulate the chemosensitivity with under-expression when compared with respective controls. In the advanced stages of pancreatic cancer with cisplatin treatment, we observed chemoresistance behavior with overexpression, especially for ß-catenin. CONCLUSIONS: The results conclude that using PKR2 and ß-catenin we are able to assess the chemosensitivity and chemoresistance nature of pancreatic cancer.

Polar distribution dynamics of Con A binding sites in embryo sacs is temporally coupled by the fertilization process.

The binding site distribution of concanavalin agglutinin (Con A) and wheat germ agglutinin (WGA) on embryo sacs at various developmental stages of Torenia fournieri L was studied by using a cooled Charge Coupled Device (CCD) and fluorescent Con A and WGA probes. The distribution patterns of Con A and WGA binding sites on embryo sacs changed during the fertilization process. The fluorescent signal indicating Con A binding sites was distributed evenly on the surface of the embryo sac wall before anthesis, was much denser on the micropylar end of the embryo sac wall and looked like a corona on the day of anthesis. After pollination, stronger fluorescence was present on the micropylar end of the embryo sac wall and the filiform apparatus (FA), showing an obvious polar distribution. When the pollen tube entered the embryo sac and reached a synergid, the fluorescence was still concentrated on the micropylar end and FA, and started to appear on the synergid. After fertilization, the polar distribution of the fluorescence gradually disappeared and an even distribution pattern was observed again on the embryo sac wall. These results revealed that the dynamic distribution of Con A binding sites was temporally coupled with the process of fertilization. WGA binding site distribution on the embryo sac was also investigated and showed a simple pattern but also regularly changed during the process of fertilization. The variation of these lectin binding sites during the fertilization process suggests that lectin binding site interactions may play a role in the process.