Beta-amylase degradation by serine endoproteinases from green barley malt

Proteolytic degradation of barley proteins is examined in green (unkilned) malt and germinating seeds from Hordeum vulgare L. cv. Harrington. Zymographic analysis of the Harrington green malt extracts using commercial preparations of barley beta-amylase incorporated as a proteolytic substrate in 2-D SDS gels shows multiple proteolytic activities. A developmental study shows that the several green malt beta-amylase-degrading activities appear at around day 2 of germination. The several activities appear to increase and decrease through 7 days of germination in a coordinated fashion. Gels treated with class-specific proteinase inhibitors show that serine-class proteinase activities are responsible for barley beta-amylase degradation seen on the zymograms. Western blot analysis also shows that proteolytic enzymes recovered from 1-D electrophoretic gels degrade barley beta-amylase, and that the degradation is inhibited by PMSF. This is the first demonstration that malt proteinases are capable of degrading important metabolic enzymes in germinating barley, and the first postulated physiological role for the serine class proteinases in barley malt.     

Estimating the onset of cambial activity in Scots pine in northern Finland by means of the heat-sum approach

We estimated the date of onset (Date(est)) of cambial activity by the pinning method in Scots pine (Pinus sylvestris L.) trees at Vanttauskoski (Site 1) and Laanila (Site 2) near the latitudinal limit of Scots pine in northern Finland. In each year and at each site, observations were made on a different set of five trees. The estimated dates of onset of cambial activity were compared with the corresponding heat sums, calculated in degree-days according to two models. Within years, Date(est) varied among trees by up to 15 days at Site 1 and up to 13 days at Site 2. Among years, mean Date(est) varied by 15.3 days at Site 1 and 12.0 days at Site 2. The overall mean Date(est) differed between sites by 6 days (June 5 at Site 1 and June 11 at Site 2). Among all trees in all years, the mean number of degree days (d.d.) calculated from mean daily temperature above a threshold of 5 degrees C before Date(est) ranged from 68.7 to 135 d.d. at Site 1 and from 37.4 to 154.7 d.d. at Site 2. Among years, the mean heat sum before Date(est )ranged from 94 to 112.5 d.d. at Site 1 and from 61.4 to 136 d.d. at Site 2. Variation among years in heat sum before Date(est) at Site 2 was highly significant, indicating that one or more factors other than, or in addition to, heat sum determines the onset of cambial activity in Scots pine. Similar results were obtained when heat sum was computed from the area between the sine wave generated by daily maximum and minimum temperature and the threshold temperature.     

Control of seed-borne pathogens on legumes by microbial and other alternative seed treatments

Greenhouse trials were carried out in order to test the efficacy of different seed treatments as alternatives to chemicals against Colletotrichum lindemuthianum cause of anthracnose on bean and Ascochyta spp. cause of Ascochyta blights on pea, respectively. Resistance inducers, commercially formulated microorganisms, non-formulated selected strains of different microorganisms (fungi, bacteria and yeasts) and plant extracts were applied as dry or liquid seed treatments on naturally infested seeds. Seedling emergence and disease incidence and/or severity were recorded. Almost all seed treatments turned out to be ineffective in controlling the Ascochyta infections, which is in line with the literature stating that these pathogens are difficult to control. The only alternative treatments that gave some control of Ascochyta spp. were thyme oil and a strain of Clonostachys rosea. The resistance inducers tested successfully controlled infections of bean by C. lindemuthianum. Among the formulated microorganisms, Bacillus subtilis-based formulations provided the best protection from anthracnose. Some strains of Pseudomonas putida, a disease-suppressive, saprophytic strain of Fusarium oxysporum and the mustard powder-based product Tillecur also proved to be effective against bean anthracnose. However, among the resistance inducers as well as among the other groups, certain agents caused a significant reduction of plant emergence. Different alternative seed treatments can therefore be used for the control of C. lindemuthianum on bean, while on pea only thyme oil and a strain of Clonostachys rosea showed some effectiveness against Ascochyta spp.     

Rasterelektronenmikroskopische Untersuchungen an Stomata von Fichten- und Tannennadeln nach Begasung und saurer Beregnung1

Scanning electron microscopical investigations on stomatal wax plugs of fir and spruce needles after fumigation and acid rain treatment Alterations of stomatal wax plugs of fir and spruce needles have been investigated in order to demonstrate the effects of different air pollutants. After acid rain treatment, and in addition to SO₂ fumigation, heavily melted wax crystals were observed. It is assumed that acid rain causes mainly the changes of the stomatal wax plugs.     

Lignification in cell cultures of Pinus radiata: activities of enzymes and lignin topochemistry

Enzymatic and topochemical aspects of lignification were studied in a Pinus radiata D. Don cell culture system that was induced to differentiate tracheary elements and sclereids with lignified secondary cell walls. The activities of the lignin-related enzymes phenylalanine ammonia lyase (PAL; EC 4.3.1.5) and cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) increased concomitantly with cell differentiation, indicating that the increase in enzyme activity was related to lignification of the cell walls and was not induced by stress. This result also indicates that PAL and CAD are suitable markers for tracheary element differentiation in coniferous gymnosperms. To further characterize lignification in this cell culture system, cellular UV-microspectrophotometry and thioacidolysis were employed. Typical UV-absorption spectra of lignin were obtained from the secondary cell walls of the tracheary elements and sclereids and from the compound middle lamella connecting differentiated cells, and the presence of lignin was confirmed by thioacidolysis. Certain aspects of lignin topochemistry in the cell walls of the tracheary elements were similar to cell walls of P. radiata wood, such as the high lignin concentration in the compound middle lamella connecting adjacent cells and the lower lignin concentration in the secondary cell walls. Therefore, the P. radiata cell culture system appears to be well suited to study the formation of lignified secondary cell walls in coniferous gymnosperms.     

Biomarker evidence for a major preservation pathway of sedimentary organic carbon

Hydrogenation processes leading from biomolecules to fossil biomarkers in anoxic sediments are crucial for the preservation of organic matter. However, these processes are still poorly understood. The present identification of several reduced carotenoids in recent sediments attests that these processes operate at the earliest stages of diagenesis without structural or stereochemical specificity, implying a nonbiological reduction pathway. Sulfur species (e.g., H2S) are the hydrogen donors involved in such reduction, as demonstrated with laboratory experiments. These reactions allow the preservation of abundant organic carbon in the rock record.     

Effect of Restricted Grazing on Hindgut pH and Fluid Balance

Six mature idle geldings were used in a crossover design to determine the effects of restricted grazing on hindgut pH and fluid balance. Initially, horses were randomly assigned to a control group (CTRL: n = 3) having access to warm-season grass pasture continuously, or a restricted grazing (RG: n = 3) group having access to pasture for 12 consecutive hours (1900-700 hours) per 24-hour period for 7 days; they were then reassigned to the opposite treatment for an additional 7 days (i.e., CTRL: n = 6; RG: n = 6). Fecal samples were collected from each horse at 700 hours on day 7 of each period and analyzed for pH and dry matter (DM) as indicators of hindgut pH and fluid balance, respectively. Jugular blood samples were also collected at 700, 1300, and 1900 hours on day 7 and were analyzed for plasma protein as an indicator of systematic fluid balance. Fecal pH and DM data were analyzed using a paired t test. Plasma protein data were analyzed as a repeated-measures design. The mean (± SE) difference between CTRL and RG for fecal pH (.01 ± .16) and fecal DM (.68 ± .6%) was not significant (P = .93 and .52, respectively). Mean plasma protein concentrations were not affected by treatment or by treatment × sample time interaction, but tended to increase (P = .07) during the sampling period regardless of treatment. In conclusion, 12 hours of grazing restriction followed by 12 hours of grazing did not negatively impact hindgut pH or fluid balance.