Micromorphology of Scirpus (Cyperaceae) and related genera in south-west Europe

Glume surface, fruit surface, perianth bristles and pollen morphology in Scirpus L. and related genera from south-west Europe have been investigated by light and scanning electron microscopy. The results of this analysis confirm the heterogeneity of the group and provide further support to the current recognition of the genera Scirpus L., Bolboschoenus (Rchb.) Palla , Scirpoides Ség., Schoenoplectus (Rchb.) Palla, Isolepis R.Br., Trichophorum Pers. and Blysmus Panz. as well as to a re-appraisal of subg. Actaeogeton (Rchb.) Oteng-Yeb. of Schoenoplectus .  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 45–58.     

On the ontogeny of Leptodora kindtii (Crustacea,Branchiopoda, Cladocera), with notes on the phylogeny of the Cladocera

Leptodora kindtii, a large predaceous cladoceran, is among the most deviant species of the Cladocera. Therefore, its phylogenetic position has traditionally proven difficult to determine. Its many peculiar features include, among others, long, stenopodous, forwardly directed trunk limbs, a posteriorly placed dorsal brood pouch, a tri-lobed lower lip, and a long, segmented abdomen. This study describes the ontogeny of L. kindtii (Haplopoda), including general body proportions, appendages, the carapace, and other external structures in an attempt to facilitate the comparison of its aberrant morphology to that of other branchiopods. In general, the early embryos are similar to the early embryos of other cladoceran taxa with respect to body shape and size and position and orientation of the early limb buds. Many of the unusual features of L. kindtii appear late in ontogeny. The carapace appears at an early stage as a pair of dorsolateral swellings in a position corresponding to the gap between the mandibles and the first pair of trunk limbs; it later becomes posteriorly transposed by a gradual fusion of its more anterior parts to the dorsal side of the thorax. The tri-lobed "lower lip," under the labrum of the late embryo and the adult, develops as a fusion of the first maxillae (lateral lobes) to an elevated sternal region behind the mouth (median lobe). The stenopodous, segmented trunk limbs in the adult develop from embryonic, elongate, subdivided limb buds, similar to those seen in early stages of other branchiopods. Two conflicting possibilities for the phylogeny of the Cladocera, involving two different positions of L. kindtii (Haplopoda), are discussed. Several characters support a sister-group relationship between the Haplopoda and Onychopoda. However, some characters support the Anomopoda and Onychopoda as sister groups, leaving the Haplopoda outside this clade. In contrast to recent suggestions, we prefer to retain the term "Cladocera" in its original sense as comprising the Haplopoda, Ctenopoda, Anomopoda, and Onychopoda.     

Redefinition of the Glyptonsternine genus Pareuchiloglanis (Teleostei: Sisoridae), with descriptions of three new genera

The genus Pareuchiloglanis (Sisoridae) contains 20 valid species and 5 species with uncertain taxonomic status. Previous morphological and molecular studies indicated that Pareuchiloglanis was non-monophyletic; nonetheless, no change was made to correct the taxonomy of the genus. Therefore, the authors conducted a systematic morphological comparison and molecular phylogenetic study on Pareuchiloglanis. The results showed that Pareuchiloglanis is a polyphyletic group. Species previously identified as Pareuchiloglanis can be divided into four groups, of which Pareuchiloglanis poilanei alone has the genus name Pareuchiloglanis. The remaining three groups of species are contained within new genera named Barbeuchiloglanis, Sineuchiloglanis and Tremeuchiloglanis. Each genus has a distinct distribution that does not cross or overlap. The molecular results supported the reliability of morphological classification and indicated that the four genera were not directly related to one another. Specifically, Sineuchiloglanis and Tremeuchiloglanis shared no recent common ancestor. In contrast, Sineuchiloglanis formed a sister group with Chimarrichthys, and Tremeuchiloglanis formed a sister group with Creteuchiloglanis and Pseudexostoma.     

A revised synonymy for Syrrhopodon trachyphyllus (Calymperaceae,Musci) and some related old world taxa

Several taxa erroneously regarded as conspecific with Syrrhopodon trachyphyllus Mont. are reinstated. These include Syrrhopodon cavifolius Sande Lac., S. planifolius P. de la Varde, S. semperi Müll. Hal., S. tosaensis Cardot and Calymperopsis katemensis Zanten (=Syrrhopodon katemensis (Zanten) L.T. Ellis, comb. nov.). Syrrhopodon ludovicae Broth. & Paris is recognized as a synonym of S. mammillosus Müll. Hal., Syrrhopodon orientalis W. D. Reese & P. J. Lin as conspecific with S. cavifolius Sande Lac., Syrrhopodon cambodiensis Tixier as synonymous with S. semperi, S. calymperoides Cardot & P. de la Varde as conspecific with Syrrhopodon prolifer Schwägr., and S. prolifer var. mossmanensis W. D. Reese is placed in synonymy with S. katemensis (Zanten) L.T. Ellis. Varieties of Syrrhopodon prolifer Schwägr. occurring in the palaeotropics are discussed.     

三种花蓟马触角感器的超微结构

采用扫描电子显微镜对花蓟马Frankliniella intonsa (Trybom)、 禾花蓟马F. tenuicornis (Uzel) 和西花蓟马F. occidentalis (Pergande) 3种国内危害严重的农业害虫的两性成虫触角感器超微结构进行观察和比较, 旨在明确3种花蓟马两性成虫触角上的感器类型、 数量、 分布及超微形态特征, 明晰3种花蓟马触角感器差异, 进而补充蓟马感器详细资料、 完善蓟马形态学研究。结果表明： 3种花蓟马两性成虫触角上均有8种感器类型, 即Böhm氏鬃毛、 钟形感器、 毛形感器、 刺形感器、 锥形感器、 腔锥形感器、 腔形感器和特殊结构感器。触角各节上感器的分布和数量并不均匀。分析结果显示, 各类感器在触角上的分布相对稳定, 具有一定规律; 近缘种间和同种两性间触角感器的形态及分布无明显差异。     

Some observations on phycobilisomes of Pterocladiella capillacea (Gelidiaceae,Rhodophyta)

ABSTRACT

Phycobilisomes (PBSs) of the red alga Pterocladiella capillacea collected in the field, were characterized both in situ and in vitro by means of a transmission electron microscope (TEM) and an image analyzer. Ultrathin sections of thalli and negatively stained PBSs after isolation revealed hemi-ellipsoidal shapes. In situ PBS dimensions were 38.5 ± 0.2 nm (height) × 38.8 ± 0.2 nm (width) × 22.6 ± 0.2 nm (thickness) in good agreement with the in vitro measurements (mean diameters of 37.6 ± 0.2 nm). These dimensions, especially the width, are smaller than those so far reported for red algae. This could depend either on the ecophysiological conditions of the thalli when harvested and/or on a staggered, symmetrically rotated and compressed disposition of biliprotein rods with respect to the allophycocyanin (APC) core. Hydroxylapatite chromatography of biliproteic extracts and SDS-PAGE electrophoresis revealed that phycoerythrin type R-(λ_max 565 nm>540 nm>498 nm) is formed by α (18.6 kDa), β (19.9 kDa), γ (30.2kDa) and γ′ (33.8 kDa) sub-units. The presence of two γ sub-units suggests that this phycoerythrin is a set of (αβ)₆γ + (αβ)₆γ′ aggregates (R-PE). A spectroscopically distinct form of phycoerythrin with different peak ratios, also found in pure fractions, is thought to be a polydisperse form (the so called r-PE). Similarity of shape and size observed in PBSs both in situ and in vitro, and fluorescence spectral characteristics of PBSs in vitro would indicate a substantial integrity of isolated PBSs. These measurements, if compared with total biliprotein content, would seem to indicate a PE fraction not assembled into PBS. A possible role of phycoerythrin in relation to the ability for a rapid adaptation of this surface species to environmental changes is suggested.     

Morphology of three species of Crotonioidea Thorel, 1876 (Acari: Oribatida), and relations between some genera

The morphology of juveniles of Archegozetes longisetosus Aoki, 1965 (Trhypochthoniidae), and two members of Malaconothridae, Trimalaconothrus angulatus Willmann, 1931, and Malaconothrus monodactylus (Michael, 1888) is described and illustrated, and the tritonymph of A. longisetosus and all juvenile stages of T. angulatus are described and illustrated for the first time. The juveniles of these species differ mainly by the presence of setae f₂ and h₃ in the larva, seta exs and pattern of cuticle in the nymphs, and some setal formulae. Based on the morphology of juvenile stages and adults, the relationship between Malaconothridae and Trhypochthoniidae is discussed, and keys to the larvae and nymphs of some European species of these families are presented.     

Corrections and additions to the Dumontiidae Santos-Flores &; Dodson, 2003 (Crustacea: Branchiopoda: Anomopoda), and implications for anomopod phylogeny

The presumed sixth limb of Dumontia Santos-Flores & Dodson, 2003 is shown to correspond to the inner part of the fifth limb. Comparison of the latter structure within the order increases the similarity between the Dumontiidae and the Daphniidae (plus Moinidae), but important similarities with the Radopoda remain. The relationship between a ‘‘daphniid line’’ and radopods needs further attention. Handling editor: K. Martens     

Comparative cytological study of four species in the genera Holomastigotes and Uteronympha n. comb. (Holomastigotidae, Parabasalia), symbiotic flagellates of termites

Cytological features observed using light, immunofluorescence, and electron microscopy of the type species Holomastigotes elongatum were compared with Holomastigotes lanceolata and to Holomastigotes flexuosum n. sp. The comparison was extended to Spirotrichonymphella pudibunda and to Uteronympha africana n. gen. n. sp., in order to present the common features of the Holomastigotidae (Spirotrichonymphida). All these species have anterior basal bodies bearing microfibrillar or striated rootlets that are reduced or absent posterior to the nucleus. An axostylar trunk is present in Holomastigotes elongatum and Holomastigotes lanceolata, whereas the axostylar microtubules do not extend posterior to the nucleus in Holomastigotes flexuosum, Spirotrichonymphella, and Uteronympha. Uteronympha africana has specific features, such as a transverse plaque inside the columella from which arise microtubules capping the nucleus, and as in Spirotrichonympha the striated lamina is present all along the flagellar lines. Uteronympha africana has ability to endocytose wood particles in addition to the osmotrophic feeding that occurs in all the Holomastigotidae.     

Phylogenetic relationships among Lactuca (Asteraceae) species and related genera based on ITS-1 DNA sequences

Internal transcribed spacer (ITS-1) sequences from 97 accessions representing 23 species of Lactuca and related genera were determined and used to evaluate species relationships of Lactuca sensu lato (s.l.). The ITS-1 phylogenies, calculated using PAUP and PHYLIP, correspond better to the classification of Feráková than to other classifications evaluated, although the inclusion of sect. Lactuca subsect. Cyanicae is not supported. Therefore, exclusion of subsect. Cyanicae from Lactuca sensu Feráková is proposed. The amended genus contains the entire gene pool (sensu Harlan and De Wet) of cultivated lettuce (Lactuca sativa). The position of the species in the amended classification corresponds to their position in the lettuce gene pool. In the ITS-1 phylogenies, a clade with L. sativa, L. serriola, L. dregeana, L. altaica, and L. aculeata represents the primary gene pool. L. virosa and L. saligna, branching off closest to this clade, encompass the secondary gene pool. L. virosa is possibly of hybrid origin. The primary and secondary gene pool species are classified in sect. Lactuca subsect. Lactuca. The species L. quercina, L. viminea, L. sibirica, and L. tatarica, branching off next, represent the tertiary gene pool. They are classified in Lactuca sect. Lactucopsis, sect. Phaenixopus, and sect. Mulgedium, respectively. L. perennis and L. tenerrima, classified in sect. Lactuca subsect. Cyanicae, form clades with species from related genera and are not part of the lettuce gene pool.     

Pollen morphology of Xanthium L. (s.l.) (Asteraceae,Asteroideae, Heliantheae,Ambrosiinae) in the Iberian Peninsula - a palynotaxonomic approach to a poisonous,allergenic and invasive genus

Abstract

The pollen morphology of the Iberian taxa of the genus Xanthium s.l. and of the non-Iberian species X. ambrosioides was studied to help to identify these poisonous, allergenic and invasive taxa and clarify their taxonomic relationships. In addition, the question of the existence and structure of a mesoaperture in the apertural system of Xanthium was also considered. The pollen grains of sections Acanthoxanthium and Xanthium clearly differ by their characters, which supports the separation of both taxa and allows for their distinction based on pollen morphology. It is suggested that the morphological and palynological differences between Xanthium and Acanthoxanthium, together with the lack of hybridisation between the two sections and the monophyly of Acanthoxanthium, could lead to the elevation of the latter to the generic status. The two species of section Xanthium present in the Iberian Peninsula (X. orientale and X. strumarium) and of section Acanthoxanthium are well separated by their palynological features. Likewise, the Iberian subspecies of Xanthium, X. orientale subsp. orientale and X. orientale subsp. italicum are palynologically distinguishable. However, no significant difference could be found between the pollen of X. strumarium subsp. strumarium and of X. strumarium subsp. brasilicum. The pollen data do not support the hypotheses of a hybrid origin for X. strumarium subsp. brasilicum. A mesoaperture intersecting the foot layer and the upper part of the endexine is present in both sections, which is congruent with the results already found for other Asteroideae.     

Structural peculiarities of the tubercles in the skin of the turbot,Scophthalmus maximus (L., 1758) (Osteichthyes,Pleuronectiformes, Scophthalmidae)

The structure of the bony tubercles of the turbot, Scophthalmus maximus (L., 1758), was examined using ground sections, microradiography, SEM, and TEM. The tubercles are small, isolated, mineralized conical plates randomly distributed in the eyed side of the body. They are composed of three layers: the outer limiting layer, the external layer, and the basal plate, which make up the thin and flat elasmoid scales of Teleostei. The main difference between regular elasmoid scales and bony tubercles lies in the organization and the growth of the basal plate. Indeed, the conical shape of the tubercle is the result of a prominent thickening of the central part of the basal plate where the collagen matrix is organized in a complicated three-dimensional network. Densely packed thick collagen fibrils form superimposed plies organized in a plywood-like structure that resembles that of the elasmoid scales but it is criss-crossed by numerous vertical sheets of thin collagen fibrils. The tubercles originate from thin and flat plates located in the skin of larvae and juveniles, whose structure is that of regular-developing elasmoid scales. Thus, the tubercles of Scophthalmus maximus could be considered as modified elasmoid scales rather than bony structures. They might be the result of specific arrangements related to the general trend of reduction of the dermal skeleton in the teleostean lineage.     

The Cassandra retrotransposon landscape in sugar beet (Beta vulgaris) and related Amaranthaceae: recombination and re-shuffling lead to a high structural variability

Background and AimsPlant genomes contain many retrotransposons and their derivatives, which are subject to rapid sequence turnover. As non-autonomous retrotransposons do not encode any proteins, they experience reduced selective constraints leading to their diversification into multiple families, usually limited to a few closely related species. In contrast, the non-coding Cassandra terminal repeat retrotransposons in miniature (TRIMs) are widespread in many plants. Their hallmark is a conserved 5S rDNA-derived promoter in their long terminal repeats (LTRs). As sugar beet (Beta vulgaris) has a well-described LTR retrotransposon landscape, we aim to characterize TRIMs in beet and related genomes.MethodsWe identified Cassandra retrotransposons in the sugar beet reference genome and characterized their structural relationships. Genomic organization, chromosomal localization, and distribution of Cassandra-TRIMs across the Amaranthaceae were verified by Southern and fluorescent in situ hybridization.Key resultsAll 638 Cassandra sequences in the sugar beet genome contain conserved LTRs and thus constitute a single family. Nevertheless, variable internal regions required a subdivision into two Cassandra subfamilies within B. vulgaris. The related Chenopodium quinoa harbours a third subfamily. These subfamilies vary in their distribution within Amaranthaceae genomes, their insertion times and the degree of silencing by small RNAs. Cassandra retrotransposons gave rise to many structural variants, such as solo LTRs or tandemly arranged Cassandra retrotransposons. These Cassandra derivatives point to an interplay of template switch and recombination processes – mechanisms that likely caused Cassandra’s subfamily formation and diversification.ConclusionsWe traced the evolution of Cassandra in the Amaranthaceae and detected a considerable variability within the short internal regions, whereas the LTRs are strongly conserved in sequence and length. Presumably these hallmarks make Cassandra a prime target for unequal recombination, resulting in the observed structural diversity, an example of the impact of LTR-mediated evolutionary mechanisms on the host genome.     

苹毛丽金龟触角嗅感器超微结构

利用扫描电镜和透射电镜对苹毛丽金龟Proagopertha lucidula (Faldermann)雌雄成虫触角嗅感器超微结构特征进行研究。结果表明:嗅感器集中于触角鳃片上,分布在触角鳃片表皮内陷形成的凹腔里,有5种感器,以板状感器为主,以外还有锥状感器、腔状感器、腔锥状感器和毛状感器。板状感器根据盘体形状的不同可分为4种类型,锥状感器根据锥体形状的差异可分为2种类型,腔锥状感器根据形状分为2种类型。嗅感器表皮有微孔和孔道微管。嗅感器内神经元的数目并不一致,1～2个不等。雄虫鳃片嗅感器总数显著多于雌性,是雌虫嗅感器总数1.8倍。其中雄性锥状感器的数目是雌性2倍,雌虫腔锥状感器数量是雄虫的4倍,雄虫板状感器数量是雌虫的2倍,雌雄腔状感器的数目无显著性差异。     

A new pollen type,C-banded and fluorochrome counterstained chromosomes,and evolution inGuatteria and related genera (Annonaceae)

Guatteria, Guatteriopsis, Guatteriella andHeteropetalum share the same conspicuous pollen type which is new for theSpermatophyta. It is zonoaperturate with a folded aperture region and an extremely reduced exine. First chromosome counts and karyotype analyses forGuatteriopsis (4 species investigated) andGuatteriella (1 species) are identical with those ofGuatteria (19 species seen): 2n = 28. The genome is characterized by diploidization and partly telocentric chromosomes. Sequentially Giemsa C- and fluorochrome banded chromosomes and interphase nuclei are described. The cuticular folding pattern is distinct forHeteropetalum only. Growth forms and ecology are reported for many species. The evolutionary pattern of theGuatteria group is discussed and compared with other genera and families.     

Why one species in New Zealand,Pugetia delicatissima (Kallymeniaceae,Rhodophyta), should become two new genera,Judithia gen. nov. and Wendya gen. nov.

Blade-forming red algae occur worldwide and, prior to DNA sequencing, had been notoriously difficult to identify and classify, especially when lacking critical reproductive features. This, coupled in New Zealand with many longstanding assumptions that taxa were identical to non-New Zealand species or genera, resulted in many misapplied names. Pugetia delicatissima R.E. Norris, an endemic New Zealand blade-forming species of the family Kallymeniaceae, is actually comprised of one existing and one new species belonging to two distinct genera, as established by our phylogenetic analyses of DNA sequences from the rbcL gene. Analyses of combined rbcL and LSU genes showed that neither is closely related to the generitype of Pugetia, the northern-eastern Pacific, P. fragilissima Kylin. We propose the names Judithia and Wendya for these two newly revealed genera. In addition to diagnostic rbcL and LSU sequences, Judithia is morphologically and anatomically characterized by rounded to oblong blades that do not taper basally at the stipe, loosely aggregated surface cortical cells and cystocarps lacking both a pericarp and an ostiole, all features observed in the holotype of P. delicatissima. Wendya, in contrast, is characterized by blades that taper both apically and basally, compactly arranged surface cortical cells and cystocarps that have both a pericarp and a distinct ostiole. The two genera also are distinguished from one other, as well as from Pugetia by features of pre- and post-fertilization development, including the number of subsidiary cells produced on carpogonial and auxiliary branch systems, whether subsidiary cells in the carpogonial branch system fuse with the supporting cell or not, and the site of origin of gonimoblast cells. Although small in area, New Zealand hosts ten of the 27 currently recognized genera in the Kallymeniaceae and is the southern-hemisphere region of greatest generic diversification in this family.     

Variable nuclear markers for a Sonoran Desert bark beetle, Araptus attenuatus Wood (Curculionidae: Scolytinae), with applications to related genera

We report eight new co-dominant nuclear markers for population genetics of the bark beetle Araptus attenuatus Wood. Several loci include introns from low-copy genes, and four cross-amplify in one or more related genera. The markers show moderate levels of polymorphism (2–19 alleles per locus), and no loci showed significant deviations from Hardy–Weinberg or linkage equilibrium across both of the two populations examined, consistent with Mendelian inheritance patterns.     

An expeditious synthesis of 4-hydroxy-2E-nonenal (4-HNE), its dimethyl acetal and of related compounds

The facile one step synthesis of 4-hydroxy-2(E)-nonenal and its dimethyl acetal via a cross-metathesis reaction between commercially available octen-3-ol and acrolein or its dimethyl acetal is reported. The method was extended to the synthesis of C₆ and C₁₂ 4-hydroxy-2(E)-enals, their dimethyl acetal and of the 4-hydroxy-2(E)-nonenoic acid (4-HNA).