TWO DIFFERENT SPECIES OF EUGLENA,E. GENICULATA AND E. MYXOCYLINDRACEA (EUGLENOPHYCEAE), ARE VIRTUALLY GENETICALLY AND MORPHOLOGICALLY IDENTICAL1

We investigated the similarity of a single Euglena myxocylindracea strain, isolated originally by Bold and MacEntee, to several Euglena geniculata strains on both morphological and DNA levels. We found the three DNA stretches, consisting of fragments coding for the parts of cytoplasmic and chloroplast small subunit rRNA, and the internal transcribed spacer (ITS2) of cytoplasmic rDNA, with the combined length of 4332 nucleotides, are identical in E. myxocylindracea and E. geniculata, strain SAG 1224‐4b. Morphological differences between E. myxocylindracea and any E. geniculata strain examined were well within the range of E. geniculata variability as well. The only difference behind the distinction of E. myxocylindracea from E. geniculata is the presence of the second chloroplast in the latter. However, we were able to induce the appearance of the second chloroplast in the cells of E. myxocylindracea and its disappearance in the cells of E. geniculata by changing the composition of the culture media. We therefore conclude that E. myxocylindracea Bold and MacEntee should be regarded as an environmental form of E. geniculata Dujardin. For the first time the morphology of E. geniculata chloroplasts was shown as revealed by confocal laser microscopy.     

A report on the mosquitoes of mainland Åland,southwestern Finland and revised list of Finnish mosquitoes

To successfully implement surveillance or control strategies for mosquitoes, up‐to‐date knowledge of regional species composition is vital. The last report regarding mosquitoes (Diptera: Culicidae) in the Åland archipelago, southwestern Finland listed 19 species (Utrio, 1979). To determine the current species diversity, one collection trip was made to mainland Åland in 2015 and three in 2016. Mosquitoes (n = 3286) were collected as both adult and immature life stages from 88 collections within 29 1‐km² areas. Fifteen of the 19 previously reported species were obtained, leaving the current status of four species uncertain. At least 11 species previously not reported from Åland, but confirmed on the Finnish mainland, were collected. Aedes geminus Peus was identified based on examination of the gonostylus, and represents a new species distribution for Finland. Anopheles maculipennis s.s. Meigen was confirmed from cytochrome c oxidase subunit I (COI) and internal transcribed spacer 2 (ITS2) sequence data and is reinstated on the list of Finnish species, along with Ochlerotatus sticticus (Meigen). Dahliana geniculata (Olivier) was found in two locations, in 2 months, indicating that there is an established population in Åland. The present data confirm that at least 27 species inhabit mainland Åland, rising to 31 when historical data are included. The Finnish mosquito fauna is increased from 38 to 41 species.     

拟鹅观草属3种植物的核型研究

对禾本科小麦族拟鹅观草属物种Pseudoroegneria geniculata、P.geniculata ssp.scythica和P.geniculata ssp.pruinifera的核型进行了研究.结果显示:P.geniculata和P.geniculata ssp.scythica为四倍体物种,P.geniculata ssp.pruinifera为六倍体物种;P.geniculata、P.geniculata ssp.scythica和P.geniculata ssp.pruinifera的核型公式分别为2n=4x=28=18m(2sat)+10sm(2sat)、2n=4x=28=28m(2sat)和2n=6x=42=36m(6sat)+6sm(2sat);P.geniculata和P.geniculata ssp.pruinifera为2A核型,而P.geniculata ssp.scythica为1A核型.研究表明:3种植物的核型存在差异;P.geniculata ssp.pruinifera的核型为首次报道,其核型明显不同于P.geniculata和P.geniculata ssp.scythica.     

DEGRADATIVE DISEASE IN ULVA RIGIDA (CHLOROPHYCEAE) ASSOCIATED WITH ACROCHAETE GENICULATA (CHLOROPHYCEAE)

A destructive disease affecting tank-cultivated Ulva rigida C. Agardh. was characterized by green spots, initially located at the base of the thalli, that spread through the host thallus and gradually caused perforations of the frond. The endophytic filamentous green alga Acrochaete geniculata (Gardner) O'Kelly was identified as the causative agent of the disease. The effects of this infection on the host varied from minor injuries to gross frond destruction. Advanced stages of infection resulted in frond wrinkling and severe tissue loss. These symptoms were caused by a primary compaction of the host cells due to a direct effect of the endophyte followed by secondary bacterial infections that became part of the degradative process initiated by the algal pathogen. Co-cultivation of healthy and diseased fronds resulted in transfer of the infection within 2 weeks; however, attempts to infect the host in the laboratory with actively reproducing suspensions of the endophyte were unsuccessful.     

Morphology and Germination of Yellow and Brown Caryopses of Aegilops Geniculata Roth (Gramineae) Population from Italy

Abstract

The germination percentage of Aegilops geniculata Roth caryopses was studied on four Italian populations (Pisa, Manfredonia, Catania and Simbirizzi). Observation of the germination trend was carried out at constant temperatures of 10°, 20° and 30°C, from maturation up to 60 days after harvesting. Spike, spikelet and caryopsis phenotypic characteristics were also studied. The populations of Pisa, Manfredonia and Simbirizzi presented two different types of caryopses: yellow caryopses - larger, heavier and composing roughly 60% of total—and brown caryopses—smaller and lighter in weight. The Catania population formed an exception in that brown caryopses were virtually absent (5%). This Sicilian accession also showed the largest spikelet size.

Yellow caryopses germinated more rapidly than the dark ones, which were shown to be endowed with longer relative dormancy, above all at 10° and 30° C. Such a phenomenon allows the two types of caryopses to have a different germination ecology, thus providing A. geniculata with a broader choice of germination opportunities and consequently favouring spread and survival of the species.     

质粒pNK866的拷贝数测定和限制酶图谱

假单胞菌(Pseudomonds)降解质粒的基因组织和表达调控的研究,以及以这些质粒为基础的高效降解环境污染物菌株和产生精细化工产品菌株的构建,是当前一个极为活跃的研究领域.但是,由于假单胞菌基因在大肠杆菌中的表达水平非常低,可用的假单胞菌载体又比较少,使这方面的研究遇到不少困难.目前使用较多的是来自质粒RSF1010的载体,但由于分子量较大,使用不方便,因此构建新的假单胞菌载体是该领域研究的一项重要内容.我们从弯曲假单胞菌(P.geniculata)AS 1.866中分离到质粒pNK866.本文报道了该质粒的拷贝数和限制酶图谱,为假单胞菌新载体的构建奠定了基础.