Extracellular matrix of <Emphasis Type="Italic">Magnaporthe oryzae</Emphasis> may have a role in host adhesion during fungal penetration and is digested by matrix metalloproteinases

Spores and infection structures such as germ tubes and appressoria of Magnaporthe oryzae, the fungus causing blast disease of wheat, produced an extracellular matrix (ECM) on the surfaces of host leaves during fungal differentiation. The chemical components and function of the ECM were studied to understand the pathological roles using two immunological techniques and ECM-digesting enzymes. The ECM was characterized by fibrous and amorphous materials, located in the spaces between fungal cell walls and plant cuticles. Immunohistochemical and immunoelectron microscopy suggested that ECM includes components positively reacted with antibodies of four animal cell adhesion factors (collagen VI, vitronectin, fibronectin and laminin) and an animal integrin α3. ECM, incubated on a cellulose membrane, was rapidly digested by matrix metalloproteinases (collagenase and gelatinase B), resulting in the detachment of most infection structures from membrane surfaces. Both ultrastructural observation and immunological responses showed that more ECM was located at the appressoria than at the spores and germ tubes. This result suggested that appressoria needed a powerful adhesion force for aggressive action of penetration pegs into plant cuticles. An erratum to this article can be found at     

Synthesis, structure analyses, and characterization of novel epigallocatechin gallate (EGCG) glycosides using the glucansucrase from Leuconostoc mesenteroides B-1299CB

In this study, three epigallocatechin gallate glycosides were synthesized by the acceptor reaction of a glucansucrase produced by Leuconostoc mesenteroides B-1299CB with epigallocatechin gallate (EGCG) and sucrose. Each of these glycosides was then purified, and the structures were assigned as follows: epigallocatechin gallate 7-O-alpha-D-glucopyranoside (EGCG-G1); epigallocatechin gallate 4'-O-alpha-D-glucopyranoside (EGCG-G1'); and epigallocatechin gallate 7,4'-O-alpha-D-glucopyranoside (EGCG-G2). One of these compounds (EGCG-G1) was a novel compound. The EGCG glycosides exhibited similar or slower antioxidant effects, depending on their structures (EGCG > or = EGCG-G1 > EGCG-G1' > EGCG-G2), and also manifested a higher degree of browning resistance than was previously noted in EGCG. Also, EGCG-G1, EGCG-G1', and EGCG-G2 were 49, 55, and 114 times as water soluble, respectively, as EGCG.     

Mild hepatic fibrosis in cholesterol and sodium cholate diet-fed rats

To date, the majority of research on hypercholesterolemia has focused on the effects of a high cholesterol diet on atherosclerosis and coronary heart disease. The toxic effects of cholesterol on the liver and the relationship between the intake of a high cholesterol diet and hepatic fibrosis, however, have not been investigated clearly or histopathologically. Male Wistar rats were fed a diet supplemented with 1.0% cholesterol and 0.3% sodium cholate for 12 weeks. Rats were sacrificed and analyzed via blood biochemistry, traditional microscopy and immunohistochemistry. Following the feeding of this diet, the rates of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase and total cholesterol in the rats were elevated consistently from week 3 and throughout the remainder of the experiment. From microscopic observation, hepatic necrosis, macrophage infiltration and steatosis increased markedly throughout the experiment. Hepatic fibrosis and myofibroblast proliferation were detected at weeks 9 and 12. Mast cell appearance was proportional to the degree of hepatic damage. These findings suggest that hepatic fibrosis is inducible by a high cholesterol diet and is likely the result of the interaction between several different cell types (i.e., macrophages, myofibroblasts, and mast cells) in an inflammatory milieu. Hypercholesterolemia should be considered as a risk factor for hepatic fibrosis as well as atherosclerosis and coronary artery disease.     

Ceratocystis smalleyi colonization of bitternut hickory and host responses in the xylem

Colonization of Carya cordiformis sapwood by Ceratocystis smalleyi and subsequent host defence responses following artificial inoculation were investigated using anatomical and histological techniques. Hyphae of C. smalleyi were observed in all sapwood xylem features confirming the ability of the pathogen to invade and colonize the xylem tissues of the host species. The fungus was isolated from within and at the margins of discoloured sapwood areas at 2 and 12 months after inoculation. General host defence responses that included vessel occlusion with gels or tyloses, lipid accumulation, and production of phenolic compounds were observed in xylem tissues of inoculated C. cordiformis stems. Pectic substances, lipids, and to a rare extent, phenolic compounds were detected in vascular gels. The lipid‐rich barriers observed likely prevent lateral expansion of the fungus in the sapwood. Furthermore, lack of fungus sporulation within vessels may restrict axial spread of the fungus. C. smalleyi appears to be a limited vascular wilt pathogen of bitternut hickory based on these observations and previously reported sap flow reduction correlated with multiple infections in artificially inoculated trees.     

桂西南地区擎天树人工林生长规律

采用树干解析的方法对桂西南地区擎天树人工林的生长规律进行研究,结果表明:32年生擎天树人工林的树高、胸径、单株材积分别为23.1 m、23.4 cm0、.516 53 m3。树高、胸径连年生长曲线和平均生长曲线均出现多次相交,且变动幅度剧烈,连年生长量在24年前后均出现明显的下降过程。而材积的变动幅度相对要小,在数量上还未达到成熟。胸径的高生长期、低生长期与树高的年份基本一致,反映了从西双版纳地区引种的擎天树在桂西南地区生长对当地气候变化十分敏感。所拟合的生长预测模型具有很高的精确度,其中,树高、胸径的最优生长模型是理查德模型,材积最优生长模型为考尔夫模型。     

Field-specific variable rate fertilizer application based on rice growth diagnosis and soil testing for high quality rice production

This study was carried out to verify the applicability of variable rate fertilization (VRF) based on soil testing and diagnosis of rice plant growth for high quality rice production of var. Chucheongbyeo at the farm level. The field trials were conducted at Icheon in Gyeonggi province on a 10 ha farm consisting of 45 experimental fields. For comparative study, 15 field trials were carried out adopting fertilizer management (FPM) practices currently used by farmers. FPM fields were managed by each rice grower using current cultivation methods, but in each VRF field fertilizer application was prescribed using soil test results and the amount of N fertilizer for top-dressing at panicle initiation stage was calculated using rice growth value at that stage. In VRF fields, the total amount of N fertilizer application was less (72 kg ha⁻¹) than that in FPM fields (103 kg ha⁻¹). However, the amount of K₂O fertilizer application was more in VRF fields (60 kg ha⁻¹) than that in FPM fields (52 kg ha⁻¹). The amount of P₂O₅ fertilizer application was similar between the VRF and FPM fields. Plant height was significantly shorter and the number of tillers was significantly more at VRF fields than at the FPM fields. Coefficient of variation (CV) of each growth characteristic measured in VRF was lower than that of FPM fields at panicle initiation stage. There was no difference in culm and panicle length and panicle number between them at the grain filling stage, but CV of panicle numbers per m² decreased in VRF compared with that of the FPM fields. Rice yield was not different between VRF and FPM fields despite higher brown rice recovery and 1,000-grain weight in VRF fields. Under VRF management, head rice yield increased due to an increase in head rice ratio accompanied by a reduction in brown rice protein content and variation of quality characteristics. These results suggest that VRF application based on soil tests and measurement of rice growth value at panicle initiation stage has the potential for quality control and production of high quality rice through increasing uniformity of growth and reducing the variability in quality among individual fields.     

Isolation and characterization of 28 polymorphic SSR loci from castor bean (<Emphasis Type="Italic">Ricinus communis</Emphasis> L.)

Castor bean (Ricinus communis) is cultivated for seed oil throughout tropical and subtropical regions but the understanding of its genetic variability is limited. Because applicable microsatellite markers are not sufficient, we isolated and characterized polymorphic simple sequence repeat (SSR) loci acquired from a microsatellite-enriched genomic DNA library of castor bean. Finally, 28 SSR loci revealed polymorphisms in a castor bean collection consisting of 72 accessions. A total of 73 alleles were detected, with an average of 3.18 alleles per locus, and the polymorphism information content (PIC) ranged from 0.03 to 0.47 (mean = 0.26). Values for observed (H_O) and expected (H_E) heterozygosity ranged from 0.00 to 0.19 (mean = 0.11) and from 0.04 to 0.54 (mean = 0.31), respectively. To understand genetic relationships within the castor bean collection, a dendrogram was constructed based on profiles of the 28 SSR loci. These newly developed SSRs will be useful tools for assessing genetic diversity and population structure in castor bean.     

CHD1 motor protein is required for deposition of histone variant H3.3 into chromatin in vivo

The organization of chromatin affects all aspects of nuclear DNA metabolism in eukaryotes. H3.3 is an evolutionarily conserved histone variant and a key substrate for replication-independent chromatin assembly. Elimination of chromatin remodeling factor CHD1 in Drosophila embryos abolishes incorporation of H3.3 into the male pronucleus, renders the paternal genome unable to participate in zygotic mitoses, and leads to the development of haploid embryos. Furthermore, CHD1, but not ISWI, interacts with HIRA in cytoplasmic extracts. Our findings establish CHD1 as a major factor in replacement histone metabolism in the nucleus and reveal a critical role for CHD1 in the earliest developmental instances of genome-scale, replication-independent nucleosome assembly. Furthermore, our results point to the general requirement of adenosine triphosphate (ATP)-utilizing motor proteins for histone deposition in vivo.     

Dawn at Vesta: testing the protoplanetary paradigm

The Dawn spacecraft targeted 4 Vesta, believed to be a remnant intact protoplanet from the earliest epoch of solar system formation, based on analyses of howardite-eucrite-diogenite (HED) meteorites that indicate a differentiated parent body. Dawn observations reveal a giant basin at Vesta's south pole, whose excavation was sufficient to produce Vesta-family asteroids (Vestoids) and HED meteorites. The spatially resolved mineralogy of the surface reflects the composition of the HED meteorites, confirming the formation of Vesta's crust by melting of a chondritic parent body. Vesta's mass, volume, and gravitational field are consistent with a core having an average radius of 107 to 113 kilometers, indicating sufficient internal melting to segregate iron. Dawn's results confirm predictions that Vesta differentiated and support its identification as the parent body of the HEDs.     

Experimental study on structure and mechanical properties of hemp/PBTG composites with fiber contents and thermal exposures

Most materials used in daily life are polymeric materials based on petrochemistry. The used polymeric materials can cause land pollution and air pollution after landfill or incineration. In contrast, natural fiber reinforced (NFR) composites are more suitable for the environment, however the reliability in terms of the durability and weatherability of NFR composites is still lacking. Thus, NFR composites require the reliability involved with durability and weatherability. In this work, poly(butylene terephthalate-co-glutarate) (PBTG), with a chemical structure similar to biodegradable PBAT, was used as the matrix in the composites, and hemp fibers were used as the reinforcement. Hemp/PBTG composites were fabricated by stacking hemp-fiberwebs and PBTG films with various fiber contents and thermal exposure times. Characteristics of the composites, such as the morphological structure, chemical structure, tensile properties, compressive properties, flexural properties, and impact strength, were analyzed to obtain the effects of fiber volume fraction and thermal exposure. As a result, hemp/PBTG composites were hardened in proportion to fiber volume fractions, and the hardening behavior of the composites increased tensile strength and flexural strength. However, the hardened structure of the composites decreased the impact strength and compressive strength of the composites. On the other hand, the mechanical properties of hemp/PBTG composites with thermal exposure times, were governed significantly by the brittleness behavior of the resin and the increased crystallinity of hemp fibers. Thus, the hemp fibers contributed to the improvements on structural stability, tensile strength and flexural strength of the hemp/PBTG composites, and increased the thermal durability of the composites with various thermal exposures.