Plant viruses and viroids in Japan

Journal of General Plant Pathology - An increasing number of plant viruses and viroids have been reported from all over the world due largely to metavirogenomics approaches with technological...     

An intact mitochondrial cox1 gene and a pseudogene with different genomic configurations are present in apple cultivars ‘Golden Delicious’ and ‘Delicious’: Evolutionary aspects

We have characterized the mitochondrial cox1 gene copies in two apple cultivars ‘Golden Delicious’ and ‘Delicious’. Both the cultivars contained an intact copy and a truncated copy of cox1. The intact ‘Golden Delicious’ and ‘Delicious’ cox1 genes, designated G-cox1 and D-cox1, respectively, were both found to be actually transcribed to give an RNA of approximately 1.7 kb. The two intact cox1 and two truncated copies (G-φcox1 and D-φcox1) shared a common 1115-bp segment flanked by four combinations of two different 5′- and 3′-sequences. PCR assay demonstrated that the configurations bearing G-cox1 and G-φcox1 existed in substoichiometric amounts within the mitochondrial genome of ‘Delicious’ whereas substoichiometric molecules carrying D-φcox1 were present in the ‘Golden Delicious’ mitochondrial genome. Although ancestor/descendant relationships cannot be inferred between the G-cox1 and D-cox1 arrangements, the results led us to hypothesize that (1) the 1115-bp segment containing part of the progenitor cox1 was duplicated, thereby generating a pseudo-cox1 copy, and (2) this was followed by homologous recombination across a portion of the 1115-bp repeats which gave rise to the descendant cox1 and pseudo-cox1 arrangements.     

Synergetic deodorant effect and antibacterial activity of composite paper containing waste tea leaves

Composite paper containing waste tea leaves was prepared to investigate the effective utilization of waste tea leaves as deodorant material. Paper containing waste green tea leaves did not have increased deodorizing ability compared with controls either against acidic odors such as hydrogen sulfide and acetic acid gases or against neutral odors such as formaldehyde and acetaldehyde gases. In contrast, the paper had excellent deodorizing ability against basic odors such as ammonia and trimethylamine gases. It was observed during additional tests conducted on paper samples containing 60 wt% waste leaves of oolong tea, black tea, pu-erh tea, or hojicha, that all the samples reduced the ammonia concentration to below 1 ppm, which is the threshold concentration for olfactory recognition, within 30 min. Further, paper containing waste green tea leaves was found to decrease the odor residual rate to 5.1% in 30 min even for a waste tea leaf content of 10 wt%. The excellent deodorizing ability of the paper could be attributed to the chemical reactions between odorous substances and the catechins found in tea leaves. After the deodorization of ammonia, paper containing waste green tea leaves was found to have increased antibacterial activity against Staphylococcus aureus.     

一株耐碳酸盐Bacillus属细菌的鉴定与特性分析

本研究从松嫩平原pH值在10.0以上、植物难以生存的斑块状裸地中分离到一株细菌SA-5,经鉴定该菌株为革兰氏染色阴性,杆状,接触酶阳性,氧化酶阴性,菌落呈橙黄色的好氧细菌,可水解淀粉。抗逆特性分析显示,菌株SA-5可在高达275mmol/L Na2CO3或pH 12.0以及2.0mol/L NaCl培养基中生长,中性条件下生长明显受到抑制,其中对碳酸盐的耐受性远高于普通植物。根据16SrDNA序列等分析结果显示,菌株SA-5属于Bacillus属,仅与菌株Bacillus aurantiacus K1-5T相似性最高,为99%,与其余已发表菌株均低于97%。由以上结果可见,菌株SA-5是Bacillus属中一株嗜碱耐盐菌,并且菌株SA-5对耐碳酸盐基因的开发具有潜在的价值。     

若干杂交水稻新组合在江汉平原的品质表现

2000年3－10月选择新近配组成功的、有苗头的优质杂交水稻组合，与在生产中已初步得到普及的组合共26个，以汕优63做对照，结合品种比较试验对其品质表现进行了考察。结果表明，新组合与原有组合相比，在粒型的长／宽比、整精米率和综合食味等方面有了较大改进，表明我国杂交水稻优质化育种已经取得了长足的进步，但在垩白粒率和垩白度方面基本没有多少改进，它们将直接影响杂交水稻优势化的整体水平；少数组合还存在直链淀粉含量偏低的问题。综合生育期、抗逆性、产量、品质与商品性进行考虑，初步认为新组合取代汕优63成为新一代当家组合已成为一种大趋势。     

Effect of temperature during ripening on grain quality of rice

Temperature during grain ripening has been shown to affect amylose content and gelatinization temperature of rice starch (1–6). These studies demonstrated that high ambient temperature results in lower amylose content and higher gelatinization temperature of the starch. Rice starches obtained from rice grains that matured at lower temperature had higher iodine blue values and were more susceptible to alkali digestion than those that ripened at higher temperature.     

The role of macronutrients in cabbage-head formation

Abstract

Cabbage plants were grown at graded levels of nitrogen supply and light intensity, and the combined effects on cabbage-head development were studied during the spring and autumn seasons.

The cabbage-head yield (i.e. dry weight of inner head leaves) was the highest at 50 ppm N in the nutrient solution, followed by 500 and 5 ppm N at full light intensity, and decreased with decrease in the, light intensity by shading. The decrease in cabbage-head yield caused by the shading was greater at high nitrogen levels during the autumn (low solar energy) season than during the spring (high solar energy) season. As the nitrogen supply increased or the light intensity decreased during both the spring and autumn seasons, nitrogen, especially soluble N, accumulated and the carbohydrate (sugar and starch) content decreased in the plants. Cabbage-head development occurred efficiently when the total N content in the outer leaves remained at about 2–3% and the carbohydrate production was large at full light intensity.     

The influence of astaxanthin supplemented dry pellets on spawning of striped jack

SUMMARY: This experiment was conducted to investigate the effect of astaxanthin supplemented steam-dry pellets on the spawning of striped jack Pseudocaranx dentex . Five months before spawning, 7-year-old fish were divided into three groups, each consisting of five females and five males. The control group was fed a raw fish mix (RF) and the test diets consisted of steam-dry pellets (DP) and steam-dry pellets supplemented with 10 p.p.m. astaxanthin (a-DP). Feeding was carried out once per day, three times a week in floating net cages. The RF and the a-DP groups produced more than three times the amount of eggs produced by the DP group. The buoyancy, fertilization, and hatching rates were higher and similar for the RF and the DP groups. Total lipid contents of the diets, eggs, and larvae were similar among the groups. Highly unsaturated fatty acids (n-3 HUFA) and polar and non-polar lipids in eggs and larvae were also related to their dietary availability. These results indicate that astaxanthin, due to its various physiological functions, improved the condition of the broodstock and enhanced total egg production but not egg quality as striped jack do not incorporate carotenoids into their eggs. Therefore we confirm that the nutritional quality of diets given to striped jack prior to spawning plays a fundamental role in egg production, quality and egg composition.     

Details of the digestive system in the midgut of Coptotermes formosanus Shiraki

Wood-feeding termites have evolved an efficient cellulose-decomposing system. The termite has two independent cellulose-digesting systems: one in the midgut and the other in the hindgut. Because the digestion system in the midgut should be the sole source of soluble sugars for the host termite, the details of the decomposition of wood particles in the midgut were clarified in one of the most common pest species, Coptotermes formosanus. The spatial distribution of cellulase in the midgut was found by immunohistochemistry, and the amount of endogenous cellulases and the volume of the endoperitrophic space were determined. The size of wood particles in the foregut and the midgut were compared. The results showed that one of the characteristics of wood degradation by termites is the mechanical grinding of food by the mandibles and the cuticular apparatus of the foregut. This process greatly increases the surface area of the substrates. Extremely high concentrations of cellulase attack the ground-up wood in the midgut, and the glucose produced is removed quickly through the peritrophic membrane.     

First report of Moroccan pepper virus on lisianthus (Eustoma grandiflorum) in Japan

In sap from plants of lisianthus (Eustoma grandiflorum) with necrotic stunt symptoms in Yamaguchi Prefecture in Japan, spherical particles with a diameter of about 30 nm were observed with transmission electron microscopy. We sequenced the complete genome of an isolate using the tombusvirus-specific primers and found that it shared about 96 % nucleotide identities with Moroccan pepper virus (MPV) in the genus Tombusvirus. The isolate reproduced necrotic stunt symptoms on lisianthus plants after mechanical inoculation. This is the first report of MPV on lisianthus in Japan.