Authors:D. Zhou, H. Gong, Z. Luan, J. Hu, and F. Wu
The study site is the Honghe National Nature Reserve, a Ramsar designated site on the Sanjiang Plain in Northeast China. We present results regarding the spatial pattern and structure of plant communities in these most important natural but continually diminishing freshwater wetlands of China to help promote both protection and restoration. By investigating three ecological levels (landscape, ecosystem and community), this paper quantifies the characteristics of spatial pattern with the aim to identify specific ecological correlations with different hydrogeomorphic features. Specifically, the research involves hierarchical mapping of vegetation types by use of remote sensed data, and the coupling of landscape indices with fluvial topographic zones that have been deduced by GIS from DEM. Statistics from historical survey data are also used to measure the degradation of marshes as well as the historical change of the hydrological regime. We found that dominant is the
Calamagrostis angustifolia — Carex
spp. community type, a wet meadow and marsh complex within the prevailing landscape mosaic of shrubland and meadow. The results suggest that the sites’ hydro-geomorphic character has decisive influence on plant community structure and composition. There is only limited direct human interference in the sites and, as a consequence, the spatial pattern of vegetation distribution is natural. However, changes to the hydrological regime as the result of extensive irrigation activity in the surrounding area has led to rapid degradation of marsh wetlands within the sites, which threatens the ecological status in this storehouse of “Natural Genes” in the reserve.
Eight malting barley cultivars were used to investigate the cultivar and environmental effects on grain protein components and the relationships between protein fractions and
-glucanase activity. The results showed there was a great variation for three protein fraction (albumin, hordein and glutelin) contents over cultivars and locations, and a distinct difference in each protein fraction content between the locations for a given cultivars. Correlation analysis indicated that
-amylase activity was significantly correlated with three protein fraction contents and there was a negative correlation between glutelin content and
-amylase activity, but
-amylase activity positively correlated with albumin or hordein content. Furthermore, there was a significant positive correlation between total protein content and
-glucanase activity, and we found the hordein and glutelin content did not show correlated with
-glucanase activity but the albumin content was a significantly negative correlation with
Authors:S.F. Wu, W. Qi, Y.F. Wang, R.X. Su, and Z.M. He
Casein peptides with calcium-chelating capacity were rapidly enriched by using a novel ceramic matrix (CM)-based Ti4+-IMAC adsorbent. The ability of calcium-chelating peptides (CCPs) to bind calcium and the physical properties of complexes formed between CCPs and calcium were investigated. Results demonstrated that the amount of calcium bound depended on the degree of hydrolysis (DH) of casein hydrolysates. The highest calcium binding capacity (683 mg g−1) occurred when bovine casein was hydrolysed by pancreatin at a DH of 0.14%, meanwhile, the calcium content of CCPs-Ca complex exhibited the maximum level (134.96 mg g−1). In addition, CCPs showed a higher radical scavenging capacity (50 µg ml−1; 99% inhibition, or an equivalent activity of 9.91×10−3 M Trolox) compared to casein digest. Moreover, Fourier-transform infrared spectroscopy and fluorescence spectroscopy were used to explore the interaction between CPPs and calcium, and the results demonstrated that phosphoserine residues as well as COO- groups of CCPs were involved in the formation of CCPs-Ca complex.
Authors:J. Wang, J. Chen, F. Dai, F. Wu, J. Yang, and G. Zhang
The effects of sowing date, nitrogen application level and timing on barley protein components and malt quality were investigated. There was a significant difference in total protein and its protein fractions among the four barley genotypes. The protein component was changeable over the different growing conditions, and the extent of change varied with protein fraction and genotype. Marked variation in malt quality over the different environments (sowing date, N fertilizer rate and applying time) was also observed. Increased N fertilizer application increased diastatic power (DP) value, but reduced malt extract. Grain protein content was significantly and positively correlated with albumin, globulin and hordein, but was not correlated with glutelin. However, glutelin was significantly related to other malt quality parameters.
Authors:X. Wu, H. Cárcamo, B. Beres, F. Clarke, R. DePauw, and B. Pang
Host plant resistance in the form of wheat with the stem lumen filled with pith has been the main strategy to manage the wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae) - a major pest of wheat in the northern Great Plains of North America. Recently a new source of resistance has been made available combining a single dominant solid pith gene from durum wheat (Triticum turgidum L. var. durum) with spring bread wheat cultivars. Our study had two objectives: (i) assess levels of C. cinctus damage and larval C. cinctus mortality in wheat with the novel solid germplasm, conventional solid-stems and susceptible cultivars; and (ii) determine plant genotype effects on populations of C. cinctus parasitoid Bracon cephi (Gahan) (Hymenoptera: Braconidae). The study was conducted in plots near Lethbridge, Alberta, Canada from 2003–2005. The novel solid-stemmed hexaploid G9608B1-L12J11BF02, solid-stemmed AC Eatonia and hollow-stemmed durum AC Navigator reduced the infestation level and girdling damage by C. cinctus. Another synthetic hexaploid B9973B03&AC4AW, hollow-stemmed AC Cadillac, McKenzie and AC Barrie were more susceptible to C. cinctus damage. Larval parasitism by B. cephi increased along with C. cinctus infestation levels. Stem solidness itself, regardless of source, had no direct negative effect on B. cephi but due to lower infestation and survival of C. cinctus in solid stem genotypes, the overall population of parasitoids was reduced. When planting monocultures of effective solid stem wheat, strategies to conserve populations of parasitoids should be considered for long term sustainable management of C. cinctus.
Authors:G.P. Li, D. Zhou, L.N. Kan, Y.W. Wu, J.F. Fan, and J. Ouyang
The inhibitory effects of phytic acid (PA) on the browning of fresh-cut chestnuts and the associated mechanisms of PA on polyphenol oxidase (PPO) and peroxidase (POD) activities were investigated. The enzymatic browning of chestnut surfaces and interiors was suppressed by soaking shelled and sliced chestnuts in a PA solution. The specific activities of PPO and POD extracted from chestnuts declined due to inhibition by PA. PA was determined to be a competitive inhibitor of both PPO and POD by Lineweaver-Burk plots. The binding modes of PA with PPO and POD were analysed by AutoDock 4.2.
Authors:Y. Li, F.Q. Lu, Y. Feng, Z.D. He, and X.L. Wu
Analysis of the binding interaction of (−)-epigallocatechin-3-gallate (EGCG) and pepsin is important for understanding the inhibition of digestive enzymes by tea polyphenols. We studied the binding of EGCG to pepsin using fluorescence spectroscopy, Fourier transform infrared spectroscopy, isothermal titration calorimetry, and protein-ligand docking. We found that EGCG could inhibit pepsin activity. According to thermodynamic parameters, a negative ΔG indicated that the interaction between EGCG and pepsin was spontaneous, and the electrostatic force accompanied by hydrophobic binding forces may play major role in the binding. Data from multi-spectroscopy and docking studies suggest that EGCG could bind pepsin with a change in the native conformation of pepsin. Our results provide further understanding of the nature of the binding interactions between catechins and digestive enzymes.
Authors:D. Huang, H. Zhang, M. Tar, Y. Zhang, F. Ni, J. Ren, D. Fu, L. Purnhauser, and J. Wu
Stripe or yellow rust (Yr), caused by Puccinia striiformis Westend. (Pst), is one of the most important wheat diseases worldwide. New aggressive Pst races can spread quickly, even between countries and continents. To identify and exploit stripe rust resistance genes, breeders must characterize first the Pst resistance and genotypes of their cultivars. To find new sources of resistances it is important to study how wheat varieties respond to Pst races that predominate in other continents. In this study we evaluated stripe rust resistance in 53 Hungarian winter wheat cultivars in China. Twenty-four cultivars (45.3%) had all stage resistance (ASR) and 1 (1.9%) had adult-plant resistance (APR), based on seedling tests in growth chambers and adult-plant tests in fields. We molecularly genotyped six Yr resistance genes: Yr5, Yr10, Yr15, Yr17, Yr18, and Yr36. Yr18, an APR gene, was present alone in five cultivars, and in ‘GK Kapos’, that also had seedling resistance. The other five Yr genes were absent in all cultivars tested.
Authors:J. Lu, G.Z. Ji, G. Li, Y.F. Wu, J. Yang, S.L. Lin, D.L. Yang, J.N. Zhao, and W.M. Xiu
Global rice supplies have been found contaminated with unapproved varieties of genetically modified (GM) rice in recent years, which has led to product recalls in several of countries. Faster and more effective detection of GM contamination can prevent adulterated food, feed and seed from being consumed and grown, minimize the potential environmental, health or economic damage. In this study, a simple, reliable and cost-effective multiplex polymerase chain reaction (PCR) assay for identifying genetic modifications of TT51-1, Kemingdao1 (KMD1) and Kefeng6 (KF6) rice was developed by using the event-specific fragment. The limit of detection (LOD) for each event in the multiplex PCR is approximately 0.1%. Developed multiplex PCR assays can provide a rapid and simultaneous detection of GM rice.