Phylogenomic analysis supports the monophyly of cryptophytes and haptophytes and the association of rhizaria with chromalveolates

Here we use phylogenomics with expressed sequence tag (EST) data from the ecologically important coccolithophore-forming alga Emiliania huxleyi and the plastid-lacking cryptophyte Goniomonas cf. pacifica to establish their phylogenetic positions in the eukaryotic tree. Haptophytes and cryptophytes are members of the putative eukaryotic supergroup Chromalveolata (chromists [cryptophytes, haptophytes, stramenopiles] and alveolates [apicomplexans, ciliates, and dinoflagellates]). The chromalveolates are postulated to be monophyletic on the basis of plastid pigmentation in photosynthetic members, plastid gene and genome relationships, nuclear "host" phylogenies of some chromalveolate lineages, unique gene duplication and replacements shared by these taxa, and the evolutionary history of components of the plastid import and translocation systems. However the phylogenetic position of cryptophytes and haptophytes and the monophyly of chromalveolates as a whole remain to be substantiated. Here we assess chromalveolate monophyly using a multigene dataset of nuclear genes that includes members of all 6 eukaryotic supergroups. An automated phylogenomics pipeline followed by targeted database searches was used to assemble a 16-protein dataset (6,735 aa) from 46 taxa for tree inference. Maximum likelihood and Bayesian analyses of these data support the monophyly of haptophytes and cryptophytes. This relationship is consistent with a gene replacement via horizontal gene transfer of plastid-encoded rpl36 that is uniquely shared by these taxa. The haptophytes + cryptophytes are sister to a clade that includes all other chromalveolates and, surprisingly, two members of the Rhizaria, Reticulomyxa filosa and Bigelowiella natans. The association of the two Rhizaria with chromalveolates is supported by the approximately unbiased (AU)-test and when the fastest evolving amino acid sites are removed from the 16-protein alignment.     

基于太平洋甲胁虱裂化线粒体基因组推测甲胁虱属祖先线粒体核型

[目的]动物典型的单一染色体线粒体基因组在甲胁虱属Hoplopleura已裂化成多个线粒体微环染色体.本研究旨在通过测定太平洋甲胁虱Hoplopleura pacifica的线粒体基因组来推测甲胁虱属祖先线粒体核型.[方法]利用Illumina HiSeq X Ten高通量测序技术对太平洋甲胁虱裂化线粒体基因组进行测定...     

Using severity factor as a parameter to optimize krill treatment under subcritical water conditions

The aim of this study was to optimize the conditions for subcritical water treatment of krill, as expressed with a single parameter: the severity factor (log R₀). Raw krill was treated under subcritical water conditions at various log R₀ values (1.54–3.75) by varying the treatment temperatures (120–180 °C) and times (0–10 min) in two different sizes of batch-type vessel (10 and 117 mL). The log R₀ value could efficiently describe changes in various properties of the obtained liquid extracts and solid residues. The most desirable shrimp-like flavor intensity and highest sensory preference were obtained for log R₀ values of 2.75–3.01. The results also proved that severity factor can be used as a single parameter to control subcritical water treatment conditions in differently sized batch-type vessels to produce shrimp-like flavor extract and residue from krill.     

太平洋甲胁虱（虱目：甲胁虱科）在其主要宿主黄胸鼠体表的空间分布格局

太平洋甲胁虱是寄生于黄胸鼠体表的一种主要吸虱昆虫 ,在云南广泛分布。应用Iwao直线回归方法及其随机偏离度检验对太平洋甲胁虱在黄胸鼠不同个体间的空间分布格局进行了研究。根据Iwao直线回归方法 ,建立了M =12 .10 +4.76M (r=0 .75 ,P <0 .0 1)的回归方程 ,所得到的α与 β值 (α =12 .10 ,β =4 .76 )均明显高于判定界线值 0和 1。对α与β值进行随机偏离度检验 ,F =6 .0 7(P <0 .0 5 ) ,由此判定太平洋甲胁虱在黄胸鼠不同个体间的空间分布格局为聚集型分布 ,这说明太平洋甲胁虱对黄胸鼠的寄生是不均匀的 ,存在聚集并有形成大小不一的吸虱个体群的趋势。     

NEW MARINE MEMBERS OF THE GENUS HEMISELMIS (CRYPTOMONADALES,CRYPTOPHYCEAE)1

Cryptomonads are a ubiquitous and diverse assemblage of aquatic flagellates. The relatively obscure genus Hemiselmis includes some of the smallest of these cells. This genus contained only two species until 1967, when Butcher described seven new marine species mainly on the basis of observations with the light microscope. However, from these seven taxa, only H. amylifera and H. oculata were validly published. Additionally, the features Butcher used to distinguish species have since been questioned, and the taxonomy within Hemiselmis has remained clouded due to the difficulty in unambiguously applying his classification and validating many of his species. As a result, marine strains are often placed into one of three species—H. rufescens Parke, H. virescens Droop, or the invalid H. brunnescens Butcher—based on cell color alone. Here we applied microscopic and molecular tools to 13 publicly available Hemiselmis strains in an effort to clarify species boundaries. SEM failed to provide sufficient morphological variation to distinguish species of Hemiselmis, and results from LM did not correlate with clades found using both molecular phylogenetic and nucleomorph genome karyotype analysis, indicating a high degree of morphological plasticity within species. On the basis of molecular characters and collection geography we recognize four new marine species of Hemiselmis—H. cryptochromatica sp. nov., H. andersenii sp. nov., H. pacifica sp. nov., and H. tepida sp. nov.—from the waters around North America.     

THE NEW GENUS AND SPECIES OSSIELLA PACIFICA (GRIFFITHSIEAE, RHODOPHYTA) FROM HAWAII AND NORFOLK ISLAND, PACIFIC OCEAN

Ossiella pacifica gen. et sp. nov. is described from sub tidal habitats (5–19 m) in the central (Hawaiian Islands) and southwestern (Norfolk Island) Pacific Ocean. Plants consist of limited prostrate axes that rapidly become erect and form ecorticate, subdichotomously branched axes bearing up to seven (mostly six) di-/to trichotomously branched, pigmented, determinate, quickly caducous whorled laterals from subapical axial cells. Two to five tetrasporangza are borne directly on the inflated basal cells of pigmented determinate laterals. One to two spermatangial fascicles are similarly placed in male plants. Subapical procarps are borne on a three-celled fertile axis, which occupies the same position as an indeterminate branch, being itself displaced laterally by the continued growth of the indeterminate axis. Procarps are bicarpogonial, the sterile cell normally associated with the supporting cell in procarps of the Griffithsieae being converted into a functional four-celled carpogonial branch . Ossiella is compared with the other membus of the tribe, and a dichotomous key to the genera is offered. On morphological grounds , Ossiella seemingly forms a perfect intermediary link along the phylogenetic lineage between the eastern Australian genus Baldockia A. Millar, the eastern American genus Calliclavula G. W. Schneid, and the widespread Anotrichium Nägeli .     

SPATIAL DISTRIBUTION PATTERN OF HOPLOPLEURA PACIFICA (ANOPLURA: HOPLOPLEURIDAE) ON ITS DOMINANT RAT HOST, RATTUS FLAVIPECTUS IN YUNNAN, CHINA

Hoplopleura pacifica is a dominant species of ectoparasitic sucking lice on the body surface of a common rat species, Rattus flavipectus in Yunan province of China. To illustrate the spatial distribution pattern of H. pacifica among the individuals of R. flavipectus, Iwao's linear regression method and a significance test of random deviation for the method were used, and a regression equation was established in the light of Iwao's method. The established equation is M*= 12.10 + 4.76M (r= 0.75, P < 0.01) where both α and β are considerably higher than 0 and 1, the border values for determining spatial pattern of populations. The calculated F value is F= 6.07 (P < 0.05) in the significance test of random deviation. The spatial distribution pattern of H. pacifica among the individuals of R. flavipectus is of aggregated distribution. The result suggests that the individuals of H. pacifica have a tendency to congregate together and form different individual groups instead of evenly distributing on the body surface of every rat host.     

Occurrence of exotic eels in natural waters of South Korea

We surveyed the proportion of anguillid eel species inhabiting South Korea natural waters. From September 2014 to August 2015, 429 eels were collected in various habitats for identification using morphological features and DNA-based molecular methods. We found 424 Japanese eels (Anguilla japonica, 98.8%), two European eels (A. anguilla, 0.5%), one American eel (A. rostrata, 0.23%), one tropical eel (A. marmorata, 0.23%), and one short-finned eel (A. bicolor pacifica, 0.23%). Three (A. anguilla, A. rostrata, and A. bicolor pacifica) are exotic species to the natural waters of South Korea; this study is the first record of their distribution in this region. Specifically, A. anguilla was found in the Lake Soyang and Cheongpyeong, while A. rostrata was found only in the Lake Cheongpyeong, and A. bicolor pacifica was found in the Geum River estuary.     

圆背角无齿蚌血细胞培养

用新设计的培养基培养了圆背角无齿蚌的血细胞,在倒置相差镜下进行了活体观察及扫描电镜摄影,发现培养的血细胞无颗粒细胞、颗粒细胞、透明细胞和类淋巴细胞,前三者均能伸出长的伪足和突起,与瓶壁紧密贴附,呈体外培养的成纤维细胞型;后者呈圆形,不与瓶壁贴附;四者的比例约为4：2：3：1。在活体内注射或在培养基上加入PHA和ConA,培养2－7d中,每天取部分供加入秋水仙素,用空气干燥法制片,作染色体观察,但未观察到转化细胞和有丝分裂相。研究结果表明,圆背角无齿蚌的颗粒细胞、无细胞和透明细胞在体外贴附玻璃表面的特征与高等动物的巨噬细胞类似,而不贴瓶的圆形细胞与高等动物的淋巴细胞类似,但在体外培养均不能繁殖,它们可能是高度分化的细胞。     

Eelgrass meadows in the California Channel Islands and adjacent coast reveal a mosaic of two species, evidence for introgression and variable clonality

BACKGROUND AND AIMS: Seagrasses are important facilitator species in shallow, soft-bottom marine environments worldwide and, in many places, are threatened by coastal development and eutrophication. One narrow-leaved species (Zostera marina) and one wide-leaved species, variously designated as Z. marina, Z. pacifica or Z. asiatica, are found off the California Channel Islands and adjacent California-Mexico coast. The aim of the present study was to confirm species identification genetically and to link patterns of genetic diversity, connectivity and hybridization among and within the populations with historical sea levels (Ice Age) or the contemporary environment. METHODS: Samples (n = 11-100) were collected from 28 sites off five California Channel Islands and six sites off the adjacent coast of southern California and Baja California, Mexico. DNA polymorphisms of the rDNA-ITS (internal transcribed spacer) cistron (nuclear), the matK intron (chloroplast) and nine microsatellite loci (nuclear) were examined in a population genetic and phylogeographic context. KEY RESULTS: All wide-leaved individuals were Z. pacifica, whereas narrow-leaved forms were Z. marina. Microsatellite genotypes were consistent with hybridization between the two species in three populations. The present distribution of Z. pacifica follows a glacial age land mass rather than present oceanographic regimes, but no link was observed between the present distribution of Z. marina and past or present environments. Island populations of Z. marina often were clonal and characterized by low genotypic diversity compared with populations along the Baja California coast. The high level of clonal connectivity around Santa Catalina Island indicated the importance of dispersal and subsequent re-establishment of vegetative fragments. CONCLUSIONS: The pristine environmental conditions of offshore islands do not guarantee maximum genetic diversity. Future restoration and transplantation efforts of seagrasses must recognize cryptic species and consider the degree of both genetic and genotypic variation in candidate donor populations.