Investigation on the biodegradability of mycotoxins nivalenol (NIV) and deoxynivalenol (DON) in a rusitec fermentor and their monitoring by HPLC/MS

Biodegradation of two B-trichothecenes nivalenol (NIV) and deoxynivalenol (DON) have been studied in a RUSITEC (rumen simulation technique) system. The fermentation studies were carried out in vessels containing the rumen fluid. To reach steady state an adaptation period of one week was carried out. The mycotoxin standards were then added into the fermentor in a concentration of 1ppm NIV and 2ppm DON. The kinetics of NIV and DON biodegradability during the fermentation process were monitored by using a rapid HPLC method combined with a mass spectrometer and an atmospheric pressure chemical ionisation (APCI^-) interface. Also the effect of mycotoxin addition on different parameters such as ammonia production, pH, gas production and volatile fatty acids have been studied.     

Systematics of Crumomyia Macquart and Alloborborus Duda (Diptera: Sphaeroceridae)

ABSTRACT. The phylogenetic relationships of two sphaerocerid genera, Alloborborus Duda (1923) and Crumomyia Macquart (1835), are analysed, and their taxonomic status within the tribe Copromyzini (= Copromyza Fallén s.lat.) is clarified. Accepted here are a monotypic Alloborborus , which includes A.pallifrons (FalléAn) from northern and central Europe, and twenty-six species of the Holarctic Crumomyia. Within Crumomyia , five species-groups are recognized: pedestris group: pedestris (Meigen); annulus group: immensa (Spuler), maculipennis (Spuler), annulus (Walker), nipponica (Richards), pruinosa (Richards); notabilis group: glabifrons (Meigen), glacialis (Meigen), absoloni (Bezzi), notabilis (Collin), rohaceki sp.n., zuskai (Roháček); nitida group: nitida (Meigen); setitibialis group: setitibialis (Spuler), pilosa sp.n., nigra (Meigen), parentela (Séguy), deemingi (Hackman), pollinodorsata (Papp), subaptera (Malloch), gelida (Hackman), fimetaria (Meigen), roserii (Rondani); unplaced species: hentscheli (Duda), hungarica (Duda), promethei (Nartshuk). Apterina Macquart, Fungobia Lioy and Speomyia Bezzi are synonymized with Crumomyia , and the following nominal species are synonymized: tuxeni Collin with nigra, freyi Hackman with setitibialis , and annulipes Duda with annulus. C. pruinosa is considered distinct from annulus, and Copromyza subaptera is placed in Crumomyia. The identity of C.glacialis , the type species of Crumomyia , is clarified, and lectotypes are designated for five nominal species: rufoannulata Duda, annulipes, annulus, flavipennis Haliday and pallifrons. The cladistic relationships of the species of Crumomyia and Alloborborus are established and their phylogeny and biogeography are discussed. Keys to the species of Crumomyia and to the Holarctic genera of the Copromyzinae are provided.     

Neural coding in antennal olfactory cells of tsetse flies (Glossina spp.)

Spike trains from individual antennal olfactory cells of tsetse flies (Glossina spp.) obtained during steady-state conditions (spontaneous as well as during stimulation with 1-octen-3-ol) and dynamic stimulation with repetitive pulses of 1-octen-3-ol were investigated by studying the spike frequency and the temporal structure of the trains. In general, stimulation changes the intensity of the spike activity but leaves the underlying stochastic structure unaffected. This structure turns out to be a renewal process. The only independently varying parameter in this process is the mean interspike interval length, suggesting that olfactory cells of tsetse flies may transmit information via a frequency coding. In spike records with high firing rates, however, the stationary records had significant negative first- order serial correlation coefficients and were non-renewal. Some cells in this study were capable of precisely encoding the onset of the odour pulses at frequencies up to at least 3 Hz. Cells with a rapid return to pre-stimulus activity at the end of stimulation responded more adequately to pulsed stimuli than cells with a long increased spike frequency. While short-firing cells process information via a frequency code, long-firing cells responded with two distinctive phases: a phasic, non-renewal response and a tonic, renewal response which may function as a memory of previous stimulations.      

大白菜萝卜细胞质雄性不育系RC7的选育及其特性研究

利用甘蓝型油菜萝卜细胞质雄性不育材料RC97-1为不育源,采用种间杂交,将RC97-1的不育性导入大白菜,再通过连续回交转育和严格经济性状选择育成新的大白菜胞质雄性不育系RC7.RC7表现为:蜜腺正常,雌蕊功能健全,能吸引蜜蜂等昆虫正常采蜜传粉;在不同的生态区和播期条件下不育性稳定,不育株率和不育度均达100%,且自然结实性良好,配合力高;高抗霜霉病,抗病毒病和黑斑病;生长整齐,叶色正常,生育期85 d,株高58.6 cm,株幅45.3 cm,叶球纵径和横径分别为48.5和16.3 cm,球形指数2.98,单球质量3.6 kg左右.RC7的一代杂种金秋70和金秋90抗病性强,适应性广,优质、丰产、稳产.因此,RC7是优良的大白菜萝卜细胞质雄性不育系,具有较高的利用价值.     

木槿的化学成分研究

为了解木槿(Hibiscus syriacus)茎的化学成分,采用MCI-gel中压柱层析、硅胶柱层析、Sephadex LH-20凝胶柱层析和高效液相色谱等色谱方法,从木槿茎85％乙醇提取物中分离得到13个化合物.根据理化性质和波谱数据,其结构分别鉴定为methyl 4-[2-hydroxy-2-(4-hydroxy...     

Why does the hoverfly Metasyrphus corollae migrate?

Abstract. 1. Migration pattern and mass appearance of the hoverfly Metasyrphus corollae (F.) (Diptera, Syrphidae) were investigated on the SE coast of Sweden in 1981. In total, 4433 hoverflies, belonging to fifteen species, were collected in water traps during 4–6 August. All but 2.2% were M.corollae , 3282 specimens being caught on 4 August, 1021 on 5 August and thirty-five on 6 August.
2. The sex ratios ( ♂/♀ ) on these dates were 1/1.6, 1/1.3 and 1/1.7. The average dry weights did not significantly differ between sexes (males 4.01 mg, females 4.02 mg).
3. M.corollae females were reproductively immature.
4. Females mostly had Senecio pollen in their guts while males mainly had Rubus pollen. The average number of pollen grains per specimen was 210 for females and 1100 for males.
5. In the summer 1980 aphids were numerous, forming a basis for a high abundance of adult hoverflies (with hibernating larvae) in 1981. Aphid density in 1981 was low and stimuli inducing egglaying were sparse. It is suggested that this pattern of aphid abundance triggers migration in M.corollae and in other aphidophagous species at irregular intervals.     

黄独微型块茎鲨烯合酶的基因克隆与序列分析

通过黄独微型块茎转录组数据库筛选到SQS基因的核心片段,利用RT-PCR技术获得SQS基因保守片段,采用RACE技术获得SQS基因的3′及5′末端序列,并采用生物信息学方法进行序列分析。结果表明,黄独微型块茎SQS基因编码序列长1548 bp,编码415 bp的氨基酸序列,理论分子量为46786.38 D,等电点(pI)为5.97。SQS蛋白为疏水性蛋白,无信号肽,含有SQS所必需的功能结构域,属于Isoprenoid_Biosym_C1 superfami?ly。黄独SQS蛋白与其他植物的SQS蛋白同源性较高,其中与盾叶薯蓣的SQS蛋白氨基酸相似性为96.4%。本试验结果从黄独微型块茎中首次获得SQS基因cDNA全长序列,该基因具有SQS同源基因的典型特征,为进一步研究黄独微型块茎SQS基因结构、基因表达和基因突变提供了基础,并为薯蓣属植物三萜合成通路关键酶SQS的正选择位点与功能的关联性分析提供了数据支持。     

Frequent mitochondrial gene introgression among high elevation Tibetan megophryid frogs revealed by conflicting gene genealogies

Historical mitochondrial introgression causes differences between a species' mitochondrial gene genealogy and its nuclear gene genealogy, making tree-based species delineation ambiguous. Using sequence data from one mitochondrial gene (cytochrome b ) and three nuclear genes (introns), we examined the evolutionary history of four high elevation Tibetan megophryid frog species, Scutiger boulengeri , Scutiger glandulatus , Scutiger mammatus and Scutiger tuberculatus . The three nuclear genes shared a similar history but the mitochondrial gene tree suggested a drastically different evolutionary scenario. The conflicts between them were explained by multiple episodes of mitochondrial introgression events via historical interspecific hybridization. 'Foreign' mitochondrial genomes might have been fixed in populations and extended through a large portion of the species' distribution. Some hybridization events were probably as old as 10 Myr, while others were recent. An F₁ hybrid was also identified. Historical hybridization events among the four species appeared to be persistent and were not restricted to the period of Pleistocene glaciation, as in several other well-studied cases. Furthermore, hybridization involved several species and occurred in multiple directions, and there was no indication of one mitochondrial genome being superior to others. In addition, incomplete lineage sorting resulting from budding speciation may have also explained some discrepancies between the mitochondrial DNA and nuclear gene trees. Combining all evidences, the former ' Scutiger mammatus ' appeared to be two species, including a new species. With the availability of a wide range of highly variable nuclear gene markers, we recommend using a combination of mitochondrial gene and multiple nuclear genes to reveal a complete species history.