Endosperm response to pollen irradiation in kiwifruit

 Cytological details of endosperm development after pollination with irradiated pollen were studied in Actinidia deliciosa (kiwifruit) cultivar Hayward. Pollinations were carried out involving five different sources of pollen (Matua, Tomuri, Burt, Berryman, and fruiting male) irradiated with gamma rays at doses of 700 and 900 Gy. Non-irradiated crosses were used as controls. Irradiated pollen induced development of approximately 25–30% of the ovules. Two types of ovules were observed: (1) with both embryo and endosperm and (2) with endosperm only. No mitotic abnormalities were found in control or irradiated endosperms. Mitotic divisions were regular and nuclei spherical and evenly spaced. However, the cells of irradiated endosperm usually contained low amounts of storage products. Ploidy level of the endosperms was evaluated by nuclear size (volume) with the use of image analyzis. Mean nuclear size in control and irradiated endosperms was 1598.3 and 750.9 μm³, respectively. It is concluded that endosperm produced after pollination with irradiated pollen is autonomous and represents the 2n level. Received: 14 October 1998 / Revision accepted: 10 March 1999     

Intraoperative radiation therapy as part of breast conserving therapy of early breast cancer—Results of one-year follow-up

Aim

The aim of this study was to assess the therapeutic effect of intraoperative radiotherapy, describe the method, and examine the occurrence of side effects and quality of life.

Background

Breast conserving therapy has recently become a standard treatment modality in patients with early invasive cancer. Radiotherapy, along with surgery, is an integral part of such treatment. The important thing of radiotherapy is to deliver a high dose to the tumour bed. One of the methods is the intraoperative radiotherapy.

Materials and methods

The analysis comprised sixty Tis-T2N0-1A breast cancer patients treated with breast conserving surgery. Patients’ mean age was 57 years (range: 32–73 years). Intraoperative radiation therapy was delivered in the operating theatre during surgery and involved a single dose of 10 Gy with an electron beam of 4, 6, 9 or 12 MeV. After that, all patients were treated with whole breast irradiation. During one year observation photos and side effects examination were made.

Results

Physical and imaging examinations performed during a one-year follow-up revealed no local or distant relapse and good tolerance of IORT. Acute mild responses to the radiotherapy occurred in 23.3% of patients. Based on the examination, a good and very good cosmetic effect was found in 78.3%, with 83.3% of patients evaluating their treatment effects in the same way.

Conclusions

Due to its exceptional physical and radiobiological properties, intraoperative radiation therapy can be a good alternative to other methods of boosting dose to the post-operative site in management of low stage breast cancer, enabling a precise therapy to the tumour bed.     

Structure and serological studies of the O-polysaccharide of Proteus penneri 75 Epitopes and subgroups of Proteus serogroup O73

The O-specific polysaccharide of the lipopolysaccharide of Proteus penneri strain 75 consists of tetrasaccharide-ribitol phosphate repeating units and resembles ribitol teichoic acids of Gram-positive bacteria. The following structure of the polysaccharide was elucidated by chemical methods and 1H and 13C NMR spectroscopy: [structure in text] where Rib-ol is ribitol. Serological studies with polyclonal antisera showed that the same structure of the O-polysaccharide occurred in two strains: P. penneri 75 and 128. A similar structure has been established earlier for the O-polysaccharide of P. penneri 103 [Drzewiecka, D., et al., Carbohydr. Res. 337 (2002) 1535-1540]. On the basis of complex serological investigations with use of two polyclonal P. penneri 75 and 103 O-antisera, five strains could be classified into Proteus O73 serogroup: P. penneri 48, 75, 90, 103 and 128, two of which (P. penneri 75 and 128) should be subdivided into subgroup 73a, 73b and three others (P. penneri 48, 90 and 103) into subgroup 73a, 73c. Epitopes responsible for the cross-reactivity of P. penneri O73 strains and a related strain of P. mirabilis O20 were tentatively defined.     

Clonal plant production from self- and cross-pollinated seed families of <Emphasis Type="Italic">Pinus sylvestris</Emphasis> (L.) through somatic embryogenesis

Several factors affecting somatic embryogenesis (SE) in Pinus sylvestris from self- and cross-pollinated seed families were studied with the aim of producing large quantities of clonal plants. Somatic embryogenesis initiation from zygotic embryos was improved on a medium with lower than standard concentrations of 2,4-dichlorophenoxyacetic acid (2.2 vs. 9.5 μM) and 6-benzyladenine (2.2 vs. 4.5 μM). On this medium, initiation rates of four controlled crosses, including one self-cross, varied from 3% to 25%. Among the maturation factors tested, the concentration of abscisic acid (ABA 80, 120 μM) had no significant effect on the production of mature somatic embryos when the medium contained 0.1 M sucrose. When sucrose concentration was 0.2 M, however, 1.4 times more mature somatic embryos were produced on medium with 80 μM compared with 120 μM ABA. Under our best maturation conditions, mature somatic embryos accumulated amounts of storage proteins that were similar to the amounts in mature zygotic embryos. Activated charcoal exerted a beneficial effect on mature somatic embryo production of 24-week-old cultures; there was no evidence of such an effect in 8-week-old cultures. Thirty-seven embryogenic lines from a self-cross and an out-cross were chosen for clonal plant production. Highly embryogenic lines produced mature somatic embryos that were more likely to convert to plants than those from less embryogenic lines. After 4 months of growth in a shade house, plantlet survival rates exceeded 70% for 31 lines out of 35. This report describes an improved method for accelerated production of large quantities of Scots pine for clonal tests.     

Structural and serological relatedness of the O-antigens of Proteus penneri 1 and 4 from a novel Proteus serogroup O72.

O-specific polysaccharides (O-antigens) of the lipopolysaccharides (LPS) of Proteus penneri strains 1 and 4 were studied using sugar analysis, (1)H and (13)C NMR spectroscopy, including 2D COSY, H-detected (1)H,(13)C HMQC, and rotating-frame NOE spectroscopy (ROESY). The following structures of the tetrasaccharide (strain 1) and pentasaccharide (strain 4) repeating units of the polysaccharides were established: [reaction: see text]. In the polysaccharide of P. penneri strain 4, glycosylation with the lateral Glc residue (75%) and O-acetylation of the lateral GalNAc residue (55%) are nonstoichiometric. This polysaccharide contains also other, minor O-acetyl groups, whose positions were not determined. The structural similarity of the O-specific polysaccharides was consistent with the close serological relatedness of the LPS, which was demonstrated by immunochemical studies with O-antisera against P. penneri 1 and 4. Based on these data, it was proposed to classify P. penneri strains 1 and 4 into a new Proteus serogroup, O72, as two subgroups, O72a and O72a,b, respectively. Serological cross-reactivity of P. penneri 1 O-antiserum with the LPS of P. penneri 40 and 41 was substantiated by the presence of an epitope(s) on the LPS core region shared by all P. penneri strains studied.     

Homeostasis of the protonmotive force in phosphorylating mitochondria

The relationship between the respiration rate and the magnitude of the electrochemical proton potential (Δμ_H⁺) in rat liver mitochondria was investigated. (1) Under the active-state conditions, the action of inhibitors of either phosphorylation (oligomycin) or respiration (rotenone, malonate) on the respiration and Δμ_H⁺ was measured. Both inhibitors diminished the respiration, whereas rotenone resulted in a decrease of Δμ_H⁺, and oligomycin produced an increase of this potential. The effect of the inhibitors was much more pronounced on the respiration rate than on Δμ_H⁺; for example, the excess of oligomycin produced a 90% inhibition of the respiration while Δμ_H⁺ was changed only by 9%. (2) Under the resting-state conditions, small concentrations of the uncoupler stimulated the respiration while changing Δμ_H⁺ to a relatively small extent. The uncoupler concentrations which doubled and tripled the respiration rate produced only 5 and 9% decrease of Δμ_H⁺, respectively. (3) The present results enabled us to propose a model describing the interrelationship between respiration and Δμ_H⁺.