Phakopsora pachyrhizi, the causal agent of Asian soybean rust

The plant pathogenic basidiomycete fungi Phakopsora pachyrhizi and Phakopsora meibomiae cause rust disease in soybean plants. Phakopsora pachyrhizi originated in Asia–Australia, whereas the less aggressive P. meibomiae originated in Latin America. In the New World, P. pachyrhizi was first reported in the 1990s to have spread to Hawaii and, since 2001, it has been found in South America. In 2004, the pathogen entered continental USA. This review provides detailed information on the taxonomy and molecular biology of the pathogen, and summarizes strategies to combat the threat of this devastating disease.
Taxonomy: Phakopsora pachyrhizi Syd. & P. Syd; uredial anamorph: Malupa sojae (syn. Uredo sojae ); Domain Eukaryota; Kingdom Fungi; Phylum Basidiomycota; Order Uredinales; Class Urediniomycetes; Family Phakopsoraceae; Genus Phakopsora ( http://www.indexfungorum.org ). The nomenclature of rust spores and spore-producing structures used within this review follows Agrios GN (2005) Plant Pathology , 5th edn. London: Elsevier/Academic Press.
Host range: In the field, P. pachyrhizi infects leaf tissue from a broad range (at least 31 species in 17 genera) of leguminous plants. Infection of an additional 60 species in other genera has been achieved under laboratory conditions.
Disease symptoms: At the beginning of the disease, small, tan-coloured lesions, restricted by leaf veins, can be observed on infected soybean leaves. Lesions enlarge and, 5–8 days after initial infection, rust pustules (uredia, syn. uredinia) become visible. Uredia develop more frequently in lesions on the lower surface of the leaf than on the upper surface. The uredia open with a round ostiole through which uredospores are released.     

Body shape differentiation at global and local geographic scales in the invasive cichlid Oreochromis mossambicus

The Mozambique tilapia Oreochromis mossambicus (Teleostei, Cichlidae) has been transplanted worldwide during the 20th century, and now belongs to the list of the most invasive species. Using a geometric morphometric approach, we describe body shape differentiation among 15 populations from native (Mozambique) and invaded (New Caledonia and Guadeloupe) ranges. A dominant phylogeographic signal is detected, despite the broad range of environmental conditions at the local scale. This result suggests that phylogeographic background rather than phenotypic plasticity responding to environmental variation constitutes the main factor correlated with shape divergence. This could result from successive founder events that occurred during the process of colonization of new geographic areas, and therefore strongly suggests heritable phenotypic differentiation. In addition, shape changes along a major axis of divergence hypothetically refer to different swimming abilities, possibly related to divergent functional requirements between the native and invaded ranges. Overall, patterns of contemporary shape diversification in O. mossambicus probably result from both phylogenetic constraints and adaptive divergence processes. We show that critically taking into account recent phylogenetic history of populations as a constraint on rapid phenotypic divergence is necessary for an improved view of contemporary evolution. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 369–381.     

On separation and identity of fern antheridiogens

Chromatographic studies show that the hormones controlling antheridiuminduction in the fern species Pteridium aquilinum (Polypodiaceae),Anemia phyllitidis and Lygodium japonicum (Schizaeaceae) aredifferent molecular entities. SCHRAUDOLF's report that gibberellic acid induces antheridiain A. phyllitidis and L. japonicum was confirmed. The activityspectrum of GAs towards species of different fern families stronglyresembles that of the native Anemia antheridiogen. However,the native antheridiogens of A. phyllitidis, and of Lygodiumjaponicum, are more species-selective in their action than isGA₃. Preliminary studies have yielded no conclusive evidenceon whether the native antheridiogens are gibberellins. (Received August 21, 1967; )     

Testosterone-“Regulon” in the Mouse Kidney

Proximal tubule cells of the mouse kidney (metanephros) are normally extremely responsive to testosterone and its intracellular metabolites. The X-linked Tfm mutation recovered by Lyon and Hawkes seems to represent an i^s (repressor noninducible) mutation of the regulatory locus.     

Reproduction and adult longevity of five species of planktonic cyclopoid copepods reared on different diets: a comparative study

1. The nutritional value of a pure algal food, the phytoflagellate Chlamydomonas reinhardtii, and a mixed diet was tested for five planktonic cyclopoid copepods (Acanthocyclops robustus, Cyclops vicinus, Cyclops abyssorum, Mesocyclops leuckarti and Thermocyclops crassus). The algae were offered at high density (4.5 × 10⁵ cells ml^–1; 22.5 mg C l^–1) in a flow-through system. The mixed diet consisted of concentrated natural plankton (rotifers, copepod nauplii, small copepodites and large phytoplankton forms) in the size range 50–150 μm and with a dry mass > 20 mg l^–1. Reproductive parameters (clutch size, interclutch periods, number of clutches produced) and adult longevity were monitored as indicators of nutritive value. 2. All species had a significantly lower reproductive output and a shorter or unchanged adult lifespan on the algal compared with the mixed diet. 3. The species differed considerably in their ability to use algae. Mesocyclops leuckarti produced no clutches with algae, and females died earlier than with the mixed food. Acanthocyclops robustus and C. vicinus produced smaller and fewer clutches, displayed a longer interclutch period and shorter (A. robustus) or similar (C. vicinus) lifespan on the algal food than on the mixed food. Thermocyclops crassus and C. abyssorum produced smaller clutches with the algal food, but interclutch period was shorter with the algal than with the mixed diet (T. crassus) or of the same length with both diets (C. abyssorum). Adult lifespan was the same under both food regimes. Unfed females produced no eggs. 4. The ability to utilize algae, the reproductive output and the reproductive allocation were not related to body size. Acanthocyclops robustus, a species of intermediate size, produced by far the largest clutches and the most eggs per lifetime under both food regimes and invested more in reproduction than the other species. 5. Reproduction was costly. Unfed and non-reproducing females of C. vicinus and C. abyssorum reached the same age or lived longer than fed and reproducing ones. 6. The adult cyclopoids tested are primarily omnivorous, but utilize algae which are frequently sufficient for egg production.     

Seed coat morphology of Aizoaceae–Sesuvioideae, Gisekiaceae and Molluginaceae and its systematic significance

Macro- and micromorphological characters of the seeds of 32 species belonging to Aizoaceae (26 species), Gisekiaceae (one species) and Molluginaceae (five species) were analysed for their taxonomic value. Seed morphology is found to be of considerable taxonomic value within the taxa investigated, although additional criteria are usually necessary for distinguishing the species. However, a subgroup of Trianthema , consisting of T. cussackiana , T. megasperma , T. pilosa , T. rhynchocalyptra and T. oxycalyptra var. oxycalyptra (Aizoaceae) shares the synapomorphy of seeds with scattered idioblast cells (papillae). There is little infrageneric variation within Sesuvium and Zaleya in contrast to Trianthema , whose seeds are considerably polymorphic. The fairly different seed structures found in Aizoaceae s.s . and Molluginaceae support their treatment as two distinct families. However, the position of Lineum (Molluginaceae) remains uncertain. Moreover, seed characters support the independence of Gisekia (Gisekiaceae) in a family of its own.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 189–206.     

Atypical Granules in the Eyes of the White Mutant of Drosophila melanogaster Are Lysosome-Related Organelles

In the pigment cells of the white mutant of Drosophila melanogaster, as described earlier, two types of abnormal granules are found by conventional electron microscopy. However, both types of abnormal granules, in addition to those in pigment cell invaginations, are also present in the cytoplasm of the photoreceptor cells. Three enzymes (acid phosphatase, peroxidase, and tyrosinase) are localized within the eyes of wild type and white mutant Drosophila melanogaster by electron microscopy. Peroxidase activity is present in lamellar bodies close to the rhabdomeral microvilli of both fly types. However the organelles containing peroxidase activity are 6-fold more frequent in the wild type than in the mutant. Acid phosphatase is present in lamellar bodies between and at the bases of the rhabdomeral microvilli of the wild type, as well as in ommochrome granules of the photoreceptor cells. In the white mutant, however, acid phosphatase was located in electron lucent vacuoles in the cytoplasm of the receptor cells. These acid phosphatase-positive vacuoles also contained both types of abnormal granules. The latter result indicates that abnormal granules in the receptor cells originate from lysosomal degradation and that targeting of lysosomal enzymes is altered in the white mutant. Due to the tyrosinase activity in the hemolymph of flies, the extracellular spaces are electron dense after DOPA incubation. Since some abnormal granules within the photoreceptor cells are not surrounded by an extracellular space, they can be assumed to originate within the photoreceptor cells.     

Climate change and the timing, magnitude, and composition of the phytoplankton spring bloom

In this article, we show by mesocosm experiments that winter and spring warming will lead to substantial changes in the spring bloom of phytoplankton. The timing of the spring bloom shows only little response to warming as such, while light appears to play a more important role in its initiation. The daily light dose needed for the start of the phytoplankton spring bloom in our experiments agrees well with a recently published critical light intensity found in a field survey of the North Atlantic (around 1.3 mol photons m^?2 day^?1). Experimental temperature elevation had a strong effect on phytoplankton peak biomass (decreasing with temperature), mean cell size (decreasing with temperature) and on the share of microplankton diatoms (decreasing with temperature). All these changes will lead to poorer feeding conditions for copepod zooplankton and, thus, to a less efficient energy transfer from primary to fish production under a warmer climate.     

Holocene environmental changes and the seal (Phocidae) fauna of the Baltic Sea: coming,going and staying

• 1 The occurrence of different species of seal (Phocidae) during the Holocene in north‐eastern Europe was influenced by a changing geological situation over the last 12 000 years, characterized by alternating freshwater, brackish and marine stages and by spatially and temporally limited opportunities for migration of marine species into the Baltic basin. The patterns of immigration by ringed seal Phoca hispida, harp seal Phoca groenlandica, grey seal Halichoerus grypus and harbour seal Phoca vitulina are reviewed here in order to understand present distributions and population sizes. Furthermore, the future of their populations is analysed.
• 2 Phoca hispida immigrated into the Baltic basin during its brackish Yoldia Stage at the Late Glacial/Early Holocene boundary and has persisted in some disjunct populations until now. A second immigration followed at the beginning of the Littorina Transgression – which resulted in the present stage of the Baltic Sea, obviously caused by the strong cooling event that occurred 6200 calibrated ¹⁴C years BC. Its present status is not threatened, but global warming will restrict suitable habitat.
• 3 Phoca groenlandica had a mid‐Holocene intermezzo in the Baltic Sea. Its later disappearance was probably caused by hunting of subadult animals by humans.
• 4 Halichoerus grypus and Phoca vitulina also immigrated at the beginning of the present stage of the Baltic Sea. Whereas H. grypus has been common from this beginning point until modern times, the population of P. vitulina persisted at a low level for millennia. Only since the 18th century has its population increased and spread over the whole Baltic Sea.