Effect of extraction time and acid concentration on the separation of proglycogen and macroglycogen in horse muscle samples

The objective of this study was to determine whether the concentrations of proglycogen (PG) and macroglycogen (MG) in biopsy samples of horse muscle are influenced by extraction time or perchloric acid (PCA) concentration. In study 1, individual muscle-biopsy samples from 10 horses were divided into 4 parts each and then randomly subjected to 4 periods of extraction (10, 20, 60, or 120 min) with 1.5 M PCA. In study 2, individual muscle-biopsy samples from 6 horses were divided into 24 pieces each and then randomly subjected to 12 combinations of extraction time (10, 20, 30, or 40 min) and PCA concentration (0.5, 1.5, or 3.0 M). The results from study 1 indicated that PG and MG concentrations are affected only after extraction for 120 min; the PG concentration decreased significantly (P < 0.05), and the MG concentration increased (not significantly). In study 2, extraction in 3.0 M PCA yielded significantly lower PG and higher MG concentrations (P < 0.05) than extraction in 0.5 or 1.5 M PCA with each of the extraction times. The results of this study further support the existence of 2 glycogen pools and demonstrate that they are not an extraction artifact. The study also suggests that the 2 pools are stable during extraction over a range of extraction times and acid concentrations. However, if the exposure to acid is very long and, or, the acid concentration is high, some of the insoluble PG appears to be hydrolyzed and to enter the MG pool.     

Conversion of four carbamoyloximes in soil samples from above and below the soil water table

2-Methyl-2-(methylsulphinyl)propionaldehyde O-methylcarbamoyloxime (aldicarb sulphoxide), aldoxycarb, oxamyl and methomyl were incubated at 10°C in soil samples taken from layers above and below shallow ground-water tables at four locations in the Netherlands. Soil samples from above the water table were incubated under moist and aerobic conditions. The anaerobic conditions below the water table were simulated by incubating the soil samples under 0.5-1 cm of ground water, and a nitrogen atmosphere. During incubation, the pH and redox potentials were measured. Less than 5% of the oxamyl and methomyl remained after one day in four water-saturated, anaerobic subsoils. The half-lives of aldicarb sulphoxide and aldoxycarb ranged from 5.1 to 131 days in the four anaerobic subsoils. Conversion rates in the aerobic soil layers above the water table were from 8 to more than 100 times lower than in the water-saturated layers in the same soil profile. Half-lives in the aerobic soils ranged from 26 days for oxamyl in loamy fine sand (pH 8.0), to 1100 days for aldoxycarb in fine sand (pH 5.0). When soil from below the water table was incubated aerobically, the conversion rates of oxamyl and aldoxycarb were drastically reduced. The opposite was found when an originally aerobic soil was incubated anaerobically. Autoclaving the incubation systems retarded the conversions.     

Comment on "Global convergence in the temperature sensitivity of respiration at ecosystem level"

Mahecha et al. (Reports, 13 August 2010, p. 838) estimated the temperature sensitivity of ecosystem respiration (Q(10)) and showed that temperature sensitivity and its site-to-site variability are lower than previously reported. We demonstrate that their Q(10) value of 1.4 is an underestimate if interpreted as the averaged sensitivities of all ecosystem components, because fast temperature fluctuations penetrate poorly into the soil.     

Subset selection in plant breeding practive

Summary Selection decisions in variety testing should partly be based on statistical motives. Useful tools for this are subset selection procedures. These procedures can also be used when the performed experiment has an incomplete block design or when a series of regional trials is studied. Various selection rules serve different selection goals, but they all need so-called selection constants. Often, these constants have to be approximated by computer simulation. For this simulation, and also for the execution of the selection rules, software has been developed and is available. Some practical adjustments and modifications of subset selection in plant breeding practice are proposed. Finally, a case study of selection in sugar beet is presented.     

The stone and boulder content of Swedish forest soils

Stone and boulder content has a strong influence on many soil processes and is a crucial factor to take into account when estimating element pools. In this paper we present the results of a large scale inventory of the stone and boulder content of forest soils, which employed a surface penetration method (Viro's method) in 1943 plots across Sweden. The volume of stones and boulders was 43.4%, on average, although it was 47.6% for the most common soil type on glacial till parent material. The variation was spatially correlated and there were regional patterns, which were related to bedrock composition and Quaternary development. A stoniness function was developed for the upper 30 cm of the mineral soil and this was used to translate the penetration depths into stone and boulder content. The function was based on a reference data set of 200 soil pits. A relationship was found between stone and boulder content and surface boulder frequency, but the strength of the relationship varied regionally. In some regions surface boulders may provide an indicator of stone and boulder content in the soil.     

Mapping of Acid Deposition Effects and Calculation of Corrosion Costs on Zinc in China

Corrosion damage to materials including objects of cultural heritage due to acid deposition has been shown to cause large costs in several studies in Europe and in the United States. So far no similar extensive studies have been performed in developing countries. The World Bank has therefore initiated and financed a study of the corrosion costs in China based on available data in the literature and obtained through contacts and visits to several institutes and organisations in China. An initial assessment of the corrosion costs in China due to acidifying pollutants has been performed using a model originally developed and applied in Europe, which has been adapted to conditions in China. Here, the model is described using zinc as an example. In the calculation of corrosion costs it is assumed that the stock of materials at risk can be allocated to census data, which enables a separate calculation of the cost for each province in China. The significant differences in corrosion attack is illustrated for zinc with a corrosion map of China based on environmental data and a dose-response function adapted for Chinese conditions including the dry and wet acid deposition effects as separate terms.     

Journeys through aroma space: a novel approach towards the selection of aroma‐enriched strawberry cultivars in breeding programmes

Consumers often criticize the sensory quality of modern strawberry cultivars. Therefore, a new and fast workflow for cultivar selection was developed to aid in the development of cultivars with enhanced aroma. This workflow consists of Headspace (HS) solid‐phase microextraction (SPME) fast GC‐MS used for high‐throughput aroma analysis of parents and hybrids. For data analysis, a chemometrical workflow was created. With a principal component analysis (PCA), the aroma similarity between the samples and a target aroma was evaluated. In order to know how the aroma profiles of the parents and hybrids are situated towards this target aroma, the Euclidean distances were calculated. These were then further used for a partial least‐squares (PLS) regression analysis to determine which aroma compounds are responsible for the observed distance to the target. By using this new approach, hybrids showing aroma profiles similar to the target aroma can be identified as most suitable candidates for further breeding cycles. Besides being time‐saving, the suggested workflow introduces aroma analysis as an integral part of breeding programmes. It prevents losing the coherence within the aroma profile and subsequently the loss of important information.