A single gene transfer of gibberellin biosynthesis gene cluster increases gibberellin production in a Fusarium fujikuroi strain with gibberellin low producibility

Fusarium fujikuroi, the causative agent of bakanae disease in rice, produces many kinds of secondary metabolites. Recently, two phylogenetic subgroups (F and G groups) of Japanese F. fujikuroi have been identified and found to have differences in their gibberellin (GA) and fumonisin production. G-group F. fujikuroi produces large amounts of GA, but is a fumonisin nonproducer. F-group produces large amounts of fumonisin, but is a GA low or nonproducer. We investigated the cause of low GA production in the F-group. Genetic mapping suggests that low GA production in the F-group strain Gfc0825009 is due to a GA gene cluster for GA biosynthesis. Analysis of the nucleotide and amino acid sequences of the genes in the GA gene cluster showed >98.4% homology between the F-group strain Gfc0825009 and the G-group strain Gfc0801001. Following a 7-day culture under low nitrogen conditions, we found that expression of P450-1, P450-4, and P450-2 in the cluster increased in the G-group strain and not in the F-group strain. We hypothesized that complementation by GA genes in the G-group strain would be required to increase GA production in the F-group strain. However, we found that this occurred with a single gene complementation of DES, P450-1, P450-4, or P450-2. Simultaneous increase in the expression of P450-1, P450-4, and P450-2 were detected in the complementary transformants. Moreover, the same phenomenon was observed by reintegration of its own P450-1. Our results suggest the presence of unknown regulatory mechanisms of the GA gene cluster in F. fujikuroi.     

茶氨酸溴香酰胺对人宫颈癌细胞体内外生长的抑制作用

将茶氨酸为母体合成的茶氨酸衍生物茶氨酸溴香酰胺(TBrC)与茶氨酸作比较,评估茶氨酸溴香酰胺对人宫颈癌细胞体内外生长的抑制作用与其分子机制。应用MTT等方法检测不同浓度的TBrC对人宫颈癌细胞体外生长的影响,运用蛋白质印迹法检测解析这些人宫颈癌细胞中与凋亡和生长密切相关蛋白的表达和药物可能的作用靶点。此外,通过建立动物肿瘤模型,评价TBrC对荷瘤裸鼠人宫颈癌生长的抑制效果。实验结果显示,TBrC抑制人宫颈癌细胞体内外生长的活性超过其母体化合物茶氨酸多倍,对小鼠生长无明显毒性;TBrC作用的分子机制之一可能与抑制VEGFR1-Bcl-2/Bax信号传导通路相关。研究结果提示,TBrC具有广泛应用于临床治疗和(或)辅助治疗人宫颈癌和其他癌症的潜力。     

Correction to: Geographical variation in spawning histories of age-1 Pacific saury Cololabis saira in the North Pacific Ocean during June and July

Fisheries Science - The article "Geographical variation in spawning histories of age 1 Pacific saury Cololabis saira in the North Pacific Ocean during June and July", written by Satoshi...     

Genetic diversity within and between sulfonylurea‐resistant and susceptible populations of Schoenoplectus juncoides in Japan

To reveal the effects of herbicide selection on genetic diversity in the outcrossing weed species Schoenoplectus juncoides, six sulfonylurea‐resistant (SU‐R) and eight sulfonylurea‐susceptible (SU‐S) populations were analysed using 40 polymorphic inter‐simple sequence repeat loci. The plants were collected from three widely separated regions: the Tohoku, Kanto and Kyushu districts of Japan. Genetic diversity values (Nei's gene diversity, h) within each SU‐S population ranged from h = 0.125 to h = 0.235. The average genetic diversity within the SU‐S populations was H_S = 0.161, and the total genetic diversity was H_T = 0.271. Although the H_S of the SU‐R populations (0.051) was lower than that of the SU‐S populations, the H_T of the SU‐R populations (0.202) was comparable with that of the SU‐S populations. Most of the genetic variation was found within the region for both the SU‐S and SU‐R populations (88% of the genetic variation respectively). Two of the SU‐R populations showed relatively high genetic diversity (h = 0.117 and 0.161), which were comparable with those of the SU‐S populations. In contrast, the genetic diversity within four SU‐R populations was much lower (from h = 0 to 0.018) than in the SU‐S populations. The results suggest that selection by sulfonylurea herbicides has decreased genetic diversity within some SU‐R populations of S. juncoides. The different level of genetic diversity in the SU‐R populations is most likely due to different levels of inbreeding in the populations.     

Nitrogen fixing activity in warty lenticellate tree barks

Detached lenticellate warty bark of Inga laurina was first shown to develop acetylene reducing activity (ARA) (18 nmol C₂H₂red·g^-1 (F.W.)·hr^-1) after a few days' incubation with ambient air containing 0.10 atm C₂H₂. Similar N₂ase development was found to occur with warty barks of many other plant species including 12 leguminous and 9 non-leguminous trees growing in wet tropical and temperate forests. Among them higher activities (>7 nmol C₂H₂ red·g^-1 (F.W.)·hr^-1) were recorded in Inga laurina, Cynometra ramiflora, Cassia siamea, Robinia pseudo-acacia, Albizia julibrissin in the leguminous plants, and Ilex crenata, Ilex pedunculosa, Rhizophora mucronata, Bruguiera gymnorrhiza and Mallotus japonicus in the non-leguminous plants. The development of ARA was often accelerated under lower pO₂ (0.05 atm) and pC₂H₂ (0.05 atm). Complete replacement of O₂ with N₂ or Ar in the incubation atmosphere resulted in full suppression of the development of N₂ase activity.

When ARA measurement was made with intact barks of natural stands (Robinia pseudo-acacia, Ilex pedunculosa and Mallotus japonicus), it was found that all of these intact barks were reducing C₂H₂ linearly without any time lag. The activities recorded were 4.6–11.5 nmol C₂H₂ red·g^-1 (F.W.)·hr^-1 corresponding to 1.19–1.27 nmol C₂H₂ red·cm^-2hr^-1. These values roughly coincided with ARA of detached warty barks of the same plant species. The present results suggest that in situ N₂-fixation in tree barks of the forests would amount to several 10 kg·ha^-1·year^-1 in temperate and tropical wet forests     

CALIBRATING CHLOROPHYLL METER (SPAD-502) READING BY SPECIFIC LEAF AREA FOR ESTIMATING LEAF NITROGEN CONCENTRATION IN SWEET SORGHUM

The chlorophyll meter (SPAD-502) is used to estimate nitrogen status of various crops. However, the relationship between SPAD readings and leaf nitrogen concentration (LNC) in sweet sorghum (Sorghum bicolor) has not been fully established. We examined the relationship between SPAD readings and LNC in sweet sorghum in a two-year study; and the effects of leaf thickness on the relationship was also examined. There was a significant relationship between the SPAD reading and LNC at each of two growth stages, but the correlation was weaker when the data for the two growth stages were pooled. This correlation improved when the specific leaf area was introduced as a second independent variable in the multiple regression analysis. This regression equation was applicable to not only different growth stages but also different seasons. The results suggest that the regression equation developed in this study can help in optimizing nitrogen fertilization for sweet sorghum production.     

杉木雄性不育性遗传机理初步分析

对杉木雄性不育原株混合授粉子代的开花情况作了观测与分析，初步认为杉木雄性不育性属核质基因作用型，即雄性不育株的细胞核有５对控制育性的隐性纯合基因，细胞质有一种控制不育性的基因，构成雄性不育基因型──Ｓ（ｍｓ＿１ｍｓ＿１ｍｓ＿２ｍｓ＿２ｍｓ＿３ｍｓ＿３ｍｓ＿４ｍｓ＿４ｍｓ＿５ｍｓ＿５）。     

杉木不同优树材性的比较研究

通过对浙江省临安县和龙泉市各１５株杉木子代优树材性测试和综合评定，认为临７５，临５，龙７，龙２５和龙２６号是优良的工程用材优树，龙２３，龙２５，龙２８和临７８号是优良的制浆造纸有材优树。其中龙２５号是两者兼优的优树，临７８和龙２６号是两者较好的优树。     

厚朴扦插繁殖技术的初步研究

影响厚朴扦插成活率的主导因子是插穗本身，插床基质也有影响，本试验所使用的促进剂、覆盖物对扦插成活率无明显作用。     

储藏物螨类防护剂研究状况及进展

文章综述了储藏物螨类防护剂的研究历史,39种储藏物螨类防护剂对不同龄期螨的毒力,39种防护剂在推食储藏过程中的杀螨效果,储藏物螨类防护研究进展。