Mitochondrial ribosomal protein S9M is involved in male gametogenesis and seed development in Arabidopsis

• Mitochondrial function is critical for cell vitality in all eukaryotes including plants. Although plant mitochondria contain many proteins, few have been studied in the context of plant development and physiology.
• We used knock‐down mutant RPS9M to study its important role in male gametogenesis and seed development in Arabidopsis thaliana.
• Knock‐down of RPS9M in the rps9m‐3 mutant led to abnormal pollen development and impaired pollen tube growth. In addition, both embryo and endosperm development were affected. Phenotype analysis revealed that the rps9m‐3 mutant contained a lower amount of endosperm and nuclear proteins, and both embryo cell division and embryo pattern were affected, resulting in an abnormal and defective embryo. Lowering the level of RPS9M in rps9m‐3 affects mitochondrial ribosome biogenesis, energy metabolism and production of ROS.
• Our data revealed that RPS9M plays important roles in normal gametophyte development and seed formation, possibly by sustaining mitochondrial function.

     

Marine insects: genital morphology, phylogeny and evolution of sea skaters, genus Halobates (Hemiptera: Gerridae)

Five species of sea skaters, genus Halobates Eschscholtz, are the only insects to have successfully colonized the open ocean. In addition, 36 species are found in sheltered coastal waters throughout tropical Indo-Pacific. The taxonomy of the genus is relatively well known, but reliable hypotheses about phylogenetic relationships are required if the biogeography and evolution of sea skaters is to be discussed in a meaningful way. This work presents the results of a study of new characters from the genital segments, especially those of the male phallus and the female gynatrial complex, and a reinterpretation for several other characters. In total 64 characters were scored for 26 species of Halobates , two species ofAsclepios and one species of Metrocoris. With Asclepios and Metrocoris species as outgroups, the character state sets were analysed cladistically using the computer program Hennig86. After critical evaluations of both characters and clades, a phylogeny for Halobates is presented and its taxonomic implications are discussed. A number of monophyletic species groups are delimited. One genus-level synonymy and three species-level synonymies are suggested. The evolution of Halobates is discussed in the light of the reconstructed phylogeny and present knowledge of the ecology and behaviour of sea skaters. A hypothesis of ecological evolution in halobatine water striders is proposed and tested.     

Phylogeny of the superfamily Gelechioidea (Lepidoptera: Obtectomera), with an exploratory application on geometric morphometrics

The superfamily Gelechioidea (Lepidoptera: Obtectomera) has a high species diversity. It consists of more than 18,400 described species and has a global distribution. Among it, large numbers of species were reported to be economically important to people's production and life. However, relationships among families or subfamilies in Gelechioidea have been exceptionally difficult to resolve using morphology or single gene genealogies. Multiple gene genealogies had been used in the molecular phylogenetic studies on Gelechioidea during the past years, but their phylogenetic relationships remain to be controversial mainly due to their limited taxa sampling relative to such high species diversity. In this paper, 89 ingroup species representing 55 genera are sequenced and added to the data downloaded from GenBank, and six species representing four closely related superfamilies are chosen as outgroup. The molecular phylogeny of Gelechioidea is reconstructed based on the concatenated data set composed of one mitochondrial marker (COI) and seven nuclear markers (CAD, EF-1ɑ, GAPDH, IDH, MDH, RpS5, wingless). The phylogenetic results, taking into consideration of the comparative morphological study, show that the clade of Gelechioidea is strongly supported and separated from other superfamilies, which further proves its monophyly. Five families are newly defined: Autostichidae sensu nov., Depressariidae sensu nov., Peleopodidae sensu nov., Ashinagidae sensu nov. and Epimarptidae sensu nov. Meanwhile, a monophyletic “SSABM” clade considered to be closely related is proposed for the first time, consisting of Stathmopodidae, Scythrididae, Ashinagidae, Blastobasidae and Momphidae. Moreover, geometric morphometric analyses using merged landmark data set from fore and hind wings of 118 representative species are conducted. The phenetic tree shows that the monophyly and phylogenetic relationships correspond with the results of molecular phylogeny largely, which well proves its importance and potential application in both phylogenetic reconstruction and species identification.     

Heteromorphic seeds of wheat wild relatives show germination niche differentiation

• Crop wild relatives are fundamental genetic resources for crop improvement. Wheat wild relatives often produce heteromorphic seeds that differ in morphological and physiological traits. Several Aegilops and Triticum species possess, within the same spikelet, a dimorphic seed pair, with one seed being larger than the other. A comprehensive analysis is needed to understand which traits are involved in seed dimorphism and if these aspects of variation in dimorphic pairs are functionally related.
• To this end, dispersal units of Triticum urartu and five Aegilops species were X‐rayed and the different seed morphs weighed. Germination tests were carried out on seeds, both dehulled and left in their dispersal units. Controlled ageing tests were performed to detect differences in seed longevity among seed morphs, and the antioxidant profile was assessed in terms of antioxidant compounds equipment and expression of selected antioxidant genes. We used PCA to group seed morphs sharing similar patterns of germination traits, longevity estimates and antioxidant profile.
• Different seed morphs differed significantly in terms of mass, final germination, germination timing, longevity estimates and antioxidant profile in most of the tested species. Small seeds germinated slower, had lower germination when left in their dispersal units, a higher antioxidant potential and were longer‐lived than large seeds. The antioxidant gene expression varied between morphs, with different patterns across species but not clearly reflecting the phenotypic observations.
• The results highlight different trait trade‐offs in dimorphic seeds of Aegilops and T. urartu, affecting their germination phenology and longevity, thereby resulting in recruitment niche differentiation.

     

Contributions to the systematic position of Hydrolea (Hydroleaceae) based on floral development

In the flower of Hydrolea palustris, unusually orientated with one sepal abaxially, organogenesis starts in following sequence: five sepals (2/5 sequence), five simultaneously initiated alternating petals, five episepalous stamens, two (seldom three) carpels forming a coenocarpous septate gynoecium. The two carpels are orientated rather in the diagonal floral plane than in the median one. Petal primordia fuse very late by forming interprimordial bridges (late sympetaly!). Many ovules develop on considerably widened placentas. On the very basis of the superior ovary a five-humped nectary disk is formed.Within Solanales (APG II 2003) late sympetaly, an intrastaminal disk and a 2-carpellate, septate, superior ovary are found in Hydroleaceae, Convolvulaceae, and Solanaceae. Enlarged axile placentas characterize Hydrolea, Solanaceae, and Sphenocleaceae but Sphenocleaceae differ considerably by early sympetaly. Montiniaceae differ by having a choripetalous corolla. Nearly diagonal orientation of the carpels seems to relate Hydrolea close to Solanaceae, but the orientation of the calyx is different.     

Morphology of the female reproductive organs of the African lion (Panthera leo)

The topography and splanchnology of the reproductive organs of the African lioness were studied and described in situ and after removal. The kidneys were located far caudally in relation to the thirteenth ribs. The suspensory ligament was very well developed, originated in a fan‐like manner from the dorsolateral abdominal wall lateral to the kidney and extended up to a few centimetres cranial to the kidney. The proper ligament of the ovary as well as the round ligament was well developed. The round ligament inserted on the medial femoral fascia. The left ovary was bigger than the right. The ovarian bursa had a short mesosalpinx that did not cover any part of the ovary and the fimbriae extended along the entire length. The urethral tuberculum as well as the urethral crest were well developed. The left uterine horn was longer than the right. The uterine tube was found to open directly into the tip of the uterine horn and not onto a papilla. The reproductive organs of the lioness resembled those of the domestic cat and dog but with some major differences.     

SYMPATRIC CONVERGENCE AND ENVIRONMENTAL CORRELATION BETWEEN TWO LAND-SNAIL SPECIES

In the southern Appalachian region of North America, the phylogenetically convergent shells of the polygyrid snails Triodopsinae Neohelix major (Binney) and Polygyrinae Mesodon normalis (Pilsbry) are even more convergent in size and shape in sympatry (7 sites) than in allopatry (23 and 10 sites). Environmental correlations account for 34% and 30% of size and shape variations in N. major (larger, taller, and more loosely coiled at northern, high-altitude, sheltered sites), but for only 14% and 9% in M. normalis (larger, flatter, and more loosely coiled at south-facing, exposed sites). The statistical significance of the sympatric convergence dropped out when these correlations were removed. This phenomenon helps account for the many cases in eastern North America of nearly identical land-snail shells in sympatry and questions the importance of competitive character displacement in the evolution of land-snail shell morphology. This apparently nonmimetic case of sympatric convergence provides an unusually precise and well-delimited, naturally replicated experiment in evolutionary morphology, which is analyzed for controlling factors in a follow-up paper.     

Decreased rate of S-adenosyl-L-homocysteine metabolism: an early event related to transformation in cells infected with Rous sarcoma virus.

An increase of methylase activity is often related to neoplastic transformation. SAH, the natural inhibitor of transmethylases, does not inhibit cell transformation induced by RSV, in contrast to one of its synthetic analogues, SIBA. This inefficiency was thought to be due to the rapid metabolism of SAH by transformed cells. We now show, that, on the contrary, 70 % of the added amount of SAH disappears in one hour in cell-free extracts of normal cell against only 14 % in extracts of transformed cells. This decreased rate of degradation occurred one day post infection. Cells infected with the non transforming RAV₁ degrade SAH at the same rate as normal cells. A decrease of SAH-hydrolase and adenosine deaminase activity was also observed in infected cells. The decrease of the first enzyme seems to be related to the transformed state, whereas that of the second enzyme seems to depend only on infection, since it is also observed in cells infected with RAV₁.     

Modelling various sculptures in the Cretaceous bivalve Inoceramus hobetsensis

The geometry of the external shell sculpture in the Late Cretaceous inoceramid bivalve Inoceramus hobetsensis Nagao & Matsumoto, 1939 was studied both empirically and theoretically. A large sample, collected from the Upper Cretaceous of Hokkaido, Japan, shows remarkably high intraspecific variation in the shell sculptural pattern. Quasi-commarginal ribs, slightly oblique to the external growth increments, occur in some specimens. These sculptures are commonly irregular in strength and spacing, and their features are successfully modelled by computer simulations when the commarginal ribs are superposed with nearly concentric divaricate rib. Computer models indicate that the divergent sculpture element, often found in other inoceramids, was present throughout the evolution of I. hobetsensis and was developing in the evolutionary lineage from I. hobetsensis nonsulcatus to I. hobetsensis hobetsensis, although it was only weakly expressed. The results also suggest that some apparently distinct sculptural patterns of I. hobetsensis are the result of minor changes in the morphogenetic program.