Effects of dried fairy shrimp Streptocephalus sirindhornae meal on pigmentation and carotenoid deposition in flowerhorn cichlid; Amphilophus citrinellus (Günther, 1864) × Cichlasoma trimaculatum (Günther, 1867)

We investigated the effects of dried fairy shrimp Streptocephalus sirindhornae meal (FS) on skin pigmentation and carotenoid deposition in flowerhorn cichlid. Six experimental diets including three treatments of FS at 10% (FS10), 20% (FS20) and 30% (FS30), two dried Spirulina sp. meal (SP) at 6% (SP6) and 12% (SP12), and a control diet (a basal diet without FS or SP) were offered for 90 days. The results demonstrate an increase in the flowerhorn cichlid skin pigmentation from alternative carotenoid feeding. Fish fed the FS diet displayed higher (P ≤ 0.05) chroma and redness values than those fed with a SP diet. The hue value (measure for skin pigmentation) was high when fish were fed with FS20 for 30 and 60 days (P ≤ 0.01). However, fish also showed high hue values when fed for 90 days with FS10 (P ≤ 0.01). The FS20 treatment gave better results than other treatments in terms of total carotenoid, canthaxanthin, astaxanthin and β‐carotene concentration in the skin and musculature. The optimum level of FS in flowerhorn cichlid diets for achieving the highest skin pigmentation was 20%.     

杧果乙烯受体基因MiETR1b的分离与表达分析

以‘紫花杧’杧果（Mangifera indica L.‘Zihua’）子叶切段为材料,采用RT-PCR结合RACE方法得到乙烯受体基因ETR1的cDNA及基因组DNA全长,命名为MiETR1b。该基因cDNA全长2 530 bp,开放读码框为2 220 bp,编码739个氨基酸;其基因组DNA全长4 116 bp,其中从起始密码子到终止密码子为3 305 bp,含有6个外显子和5个内含子。氨基酸序列多重比对及系统发育树结果显示MiETR1b与MiETR1亲缘关系最近,与CsERS1、DlETR1、TcERS1、PtrETR1有较高的同源性,且具有保守的GAF域和组氨酸激酶域。这些结果表明,MiETR1b为ETR1家族同源基因。荧光定量PCR结果表明,MiETR1b在杧果子叶切段不定根形成过程中在远轴端和近轴端都有表达,其中远轴端0.25 ~ 2 d的表达量显著上调;吲哚丁酸（IBA）和2,3,5–三碘苯甲酸（TIBA）预处理后分别在1 d和6 h显著下调。另一方面,在培养的初期,即0.5 ~ 1 d,乙烯释放量相对较高,4 d及其以后的乙烯释放量急剧下降,表明杧果子叶切段不定根形成过程中有较多乙烯生成,提示MiETR1b可能参与了不定根的形成。     

Frequency of brown rot fungi on blossoms and fruit in stone fruit orchards in Greece

Brown rot is a devastating disease of stone fruits caused by Monilinia spp. This study was conducted to investigate the disease aetiology on blossoms and fruit in peach, apricot, sweet cherry and plum orchards, in Greece. In total, 1433 isolates obtained from orchards located in the main stone fruit production regions of Greece were identified to species based on the presence/size of a cyt b intron. Monilinia laxa and M. fructicola were detected at frequencies of 59 and 41%, respectively, while M. fructigena was absent. Monilinia fructicola was more common on fruit whereas M. laxa occurred in similar frequency on blossoms and fruit. Monilinia laxa was replaced by M. fructicola in fruit infections of peach in both regions investigated and in fruit infections of plum in the Imathia region. Assessments of aggressiveness of 30 isolates of both species on the petals and fruits of the hosts showed that M. fructicola isolates were more aggressive. This suggests that the predominance of M. laxa on the blossoms cannot be explained by higher aggressiveness. Measurements of the effect of temperature on mycelial growth showed that M. laxa isolates had a higher growth rate than M. fructicola at the lowest temperature tested of 5°C, whereas M. fructicola isolates showed higher growth rates at higher temperatures. The observed high frequency of M. fructicola in Greece represents a major threat for stone fruit production. Furthermore, the information obtained about delineation of species and plant organ preference could be useful for the implementation of disease management strategies.     

Screening of Chinese cabbage mutants produced by 60Co γ‐ray mutagenesis of isolated microspore cultures

Since the release of the Chinese cabbage genome sequence, increasing interest has focused on the functional analysis of unidentified genes in Chinese cabbage. Mutant analysis forms the basis of functional genomics research. To produce a variety of Chinese cabbage mutants in the same genetic background, buds containing late uninucleate spores from a doubled haploid line of the Chinese cabbage variety ‘Fukuda 50’ were irradiated with ⁶⁰Co γ‐rays at doses of 20, 40 and 60 Gy. Then, the treated microspores were isolated and cultured. A total of 492 putative M₀ mutants were isolated from 1483 regenerated plants. Of these, six M₁ mutants were verified; the mutant frequency was 0.41%. These mutants comprise a mutant library that includes one plant shape mutant, two flower mutants and three male sterile mutants. Pollen viability detection and DNA flow cytometry were used to determine the ploidy of the regenerated plants. Some of the mutants isolated in this study may be useful for Chinese cabbage breeding and functional genomics research.     

The effect of poly‐β‐hydroxybutyrate on the performance of Chinese mitten crab (Eriocheir sinensis Milne‐Edwards) zoea larvae

Two experiments were conducted regarding the effect of poly‐β‐hydroxybutyrate (PHB) on the survival and development of Chinese mitten crab (Eriocheir sinensis Milne‐Edwards) larvae. Different PHB delivery approaches (particulate, enriched in filter feeding prey, or a combination of both) and feeding levels were applied to crab larvae from the zoea 2 (Z2) up to the megalopa stage. Bio‐encapsulation into rotifers and Artemia at a PHB dose of 100 mg L^?1 seemed an efficient approach to deliver PHB to the larvae and resulted in a significantly enhanced survival, development rate and osmotic tolerance. The results indicate that PHB should only be applied as a feed additive rather than as a food source, and that the availability of an adequate amount of nutrients seems to be of major importance for the PHB to induce these beneficial effects.     

Epitheliocystis in lake trout Salvelinus namaycush (Walbaum) is associated with a β‐proteobacteria

Lake trout Salvelinus namaycush (Walbaum) raised for stocking experienced yearly (2011–13) winter epizootics of epitheliocystis. Affected fish were dispersed on the bottom of the tank, had decreased feed and fright response, and mortality often reached 40%. Peak mortality occurred within 3 weeks of the appearance of clinical signs, and outbreaks typically lasted 6 weeks. Affected fish had no gross lesions but histologically had branchial epithelial necrosis and lamellar hyperplasia, with small to large numbers of scattered epithelial cells containing 10‐ to 20‐μm inclusions. A longitudinal study was undertaken of one annual outbreak, and lamellar hyperplasia was most closely associated with mortality. The number of inclusions was statistically greater (P < 0.05) before and during peak mortality, but inclusions were present in low numbers before clinical signs occurred. Results of histochemical staining, immunohistochemistry and transmission electron microscopy supported the presence of a β‐proteobacteria rather than a Chlamydiales bacterium within inclusions. PCR primers to identify Chlamydiales did not give consistent results. However, the use of universal 16S rDNA bacterial primers in conjunction with laser capture microdissection of inclusions demonstrated that a β‐proteobacteria was consistently associated with affected gills and is more likely the cause of the disease in lake trout.     

稻曲病气象风险评估及适宜度等级预测技术

为了弄清适宜稻曲病发生发展的气象条件以及对应的气象适宜度等级,提高水稻气象型病害防控能力,本文利用江苏省稻曲病大田调查资料,结合历史气象资料,通过评估发病敏感时段和致病风险,以及分析江苏省稻曲病最大成灾风险度出现日期以及空间分布情况,指出8月下旬为稻曲病高发期,对于发病风险高且程度重的沿淮、沿江以及江淮之间地区需要加强病害防御。在此基础上,综合考虑不同连续致病天数对稻曲病流行的影响,利用最优化技术,构建了综合稻曲病指数,并划分气象条件适宜度等级。通过单站和多站检验发现该指数对"中等、大流行"发病实况的判定准确率极高,但容易高估"轻度流行"的程度。     

Occurrence of soil insect pests: insight from classical identification supplemented with DNA barcoding

White grubs are key vegetables soil pests in Rwanda. However, aforementioned insect pests are unknown. We monitored adults with light traps and excavated larvae during cropping seasons of 2014 and 2015. Totally, 42 species were collected. The peak flights of key insect pests occurred from August to October and mid-March. The cytochrome C oxidase I (COI) gene was amplified with polymerase chain reaction (PCR) and used to compare larval DNA against DNA from adults by using MEGA 6, GMYC and ABGD software. The results obtained validate the use of COI gene. The identification results will help to predict critical time for management practices.     

牛支原体pdhα和pdhβ基因的克隆、原核表达及亚细胞的定位

牛支原体(Mycoplasma bovis,M.b)是牛(Bos taurus)的一种重要致病性支原体,感染后可引起牛多种疾病.丙酮酸脱氢酶复合体E1 (pyruvate dehydrogenase E1,PDHc E1)是参与生物体糖代谢过程的一个限速酶,广泛存在于微生物、哺乳动物及高等植物中,其直接影响丙酮酸向乙酰辅酶A的转化.本研究参照GenBank中M.b PG45株的PDHc E1α亚基基因pdhα和PDHc E1β亚基基因pdhβ序列设计引物,通过PCR扩增获得M.b武威株的pdhα (GenBank登录号:KU355295)及pdhβ基因(GernBank登录号:KU355296),在序列测定的基础上应用重叠延伸PCR (Overlap PCR)技术完成基因优化并构建原核表达质粒pET-pdhα和pET-pdhβ.表达质粒分别转化大肠杆菌(Escherichia coli) BL21 (DE3)后经异丙基硫代半乳糖苷(isopropy1β-D-1-thiogalactopyranoside,IPTG)诱导表达重组PDHc E 1α亚基融合蛋白PDHA及PDHcE1β亚基蛋白PDHB.纯化表达产物并分别免疫新西兰兔(Oryctolagus cuniculus)制备多克隆抗体,进而应用Western blot及酶联免疫吸附试验(enzyme linked immunosorbent assay,ELISA)对M.b PDHcE1α亚基和PDHc E1β亚基在细胞内的分布进行了初步研究.结果表明,经IPTG的诱导,pdhα与pdhβ基因在大肠杆菌BL21(DE3)中均成功表达,重组蛋白rPDHA及rPDHB的分子量分别约为40和37kD,且均有良好的免疫原性,而Western blot及ELISA结果证实E1α和E1β在牛支原体细胞膜上和胞浆中均有分布且分布量相当.本研究结果为进一步研究M.b生物学功能提供了基础资料.