The controversial origin of the abdominal appendage‐like processes in immature insects: Are they true segmental appendages or secondary outgrowths? (Arthropoda hexapoda)

In this article, I review the major characteristics of different types of appendage‐like processes that develop at the abdominal segments of many immature insects, and I discuss their controversial morphological value. The main question is whether the abdominal processes are derived from segmental appendages serially homologous to thoracic legs, or whether they are “secondary” outgrowths not homologous with true appendages. Morphological and embryological data, in particular, a comparison with the structure and development of the abdominal appendages in primitive apterygote hexapods, and data from developmental genetics, support the hypothesis of appendicular origin of many of the abdominal processes present in the juvenile stages of various pterygote orders. For example, the lateral processes, such as the tracheal gills in aquatic nymphs of exopterygote insects, are regarded as derived from lateral portions of appendage primordia, homologous with the abdominal styli of apterygotan insects; these processes correspond either to rudimentary telopodites or to coxal exites. The ventrolateral processes, such as the prolegs of different endopterygote insect larvae, appear to be derived from medial portions of the appendicular primordia; they correspond to coxal endites. These views lead to the rejection of Hinton's hypothesis (Hinton [1955] Trans R Entomol Soc Lond 106:455–545) according to which all the abdominal processes of insect larvae are secondary outgrowths not derived from true appendage anlagen. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.     

Morphological analysis of female gametophyte development in the bel1 stk shp1 shp2 mutant

Abstract

In Arabidopsis thaliana, cell fate in developing ovules is determined by the action of the homeodomain factor BELL1 (BEL1) and of the MADS-box factors SEEDSTICK (STK), SHATTERPROOF1 (SHP1) and SHP2. The analysis of the bel1 and the stk shp1 shp2 mutants revealed that the functional megaspore is formed, however, it does not proceed into megagametogenesis. In the bel1 stk shp1 shp2, quadruple mutant megasporogenesis does not take place. In this article we describe a detailed morphological analysis of the quadruple mutant, and we discuss the possibility that BELL1, STK, SHP1 and SHP2 not only control integument identity determination and development, but that they might also play a role during megasporogenesis.     

Morphometry and composition of aragonite and vaterite otoliths of deformed laboratory reared juvenile herring from two populations

Vaterite otoliths were sampled from two reared populations (Celtic and Clyde Seas) of juvenile herring Clupea harengus. The crystallography, elemental composition and morphometry were analysed and compared with those of normal aragonite otoliths. The incidence of vaterite otoliths in the juveniles sampled (n = 601) ranged from 7·8% in the Clyde population to 13·9% in the Celtic Sea population, and was 5·5% in the small sample (n = 36) of wild adults examined. In all but one case fish had only one vaterite otolith; the corresponding otolith of the pair was completely aragonite. Although the majority of the juveniles sampled showed craniofacial deformities, there was no link between the skull or jaw malformation and the incidence of vaterite otoliths. All vaterite otoliths had an aragonite inner area, and vaterite deposition began sometime after the age of 90 days. The vaterite otoliths were larger and lighter than their corresponding aragonite partners, and were less dense as a consequence of the vaterite crystal structure. The vaterite areas of the otoliths were depleted in Sr, Na and K. Concentrations of Mn were higher in the vaterite areas. The transition between the aragonite inner areas and the vaterite areas was sharply delineated. Within a small spatial scale (20 μm³) in the vaterite areas, however, there was co‐precipitation of both vaterite and aragonite. The composition of the aragonite cores in the vaterite otoliths was the same as in the cores of the normal aragonite otoliths indicating that the composition of the aragonite cores did not seed the shift to vaterite. Vaterite is less dense than aragonite, yet the concentrations of Ca analysed with wavelength‐dispersive spectrometry (WDS) were the same between the two polymorphs, indicating that Ca concentrations measured with WDS are not a good indicator of hypermineralized zones with high mineral density. The asymmetry in density and size of the otoliths may cause disruptions of hearing and pressure sensitivity for individual fish with one vaterite otolith, however, the presence of vaterite otoliths did not seem to affect the growth of these laboratory reared juvenile herring.     

Effect of tower base painting on willow ptarmigan collision rates with wind turbines

1. Birds colliding with turbine rotor blades is a well‐known negative consequence of wind‐power plants. However, there has been far less attention to the risk of birds colliding with the turbine towers, and how to mitigate this risk.
2. Based on data from the Smøla wind‐power plant in Central Norway, it seems highly likely that willow ptarmigan (the only gallinaceous species found on the island) is prone to collide with turbine towers. By employing a BACI‐approach, we tested if painting the lower parts of turbine towers black would reduce the collision risk.
3. Overall, there was a 48% reduction in the number of recorded ptarmigan carcasses per search at painted turbines relative to neighboring control (unpainted) ones, with significant variation both within and between years.
4. Using contrast painting to the turbine towers resulted in significantly reduced number of ptarmigan carcasses found, emphasizing the effectiveness of such a relatively simple mitigation measure.

     

A DNA Damage Checkpoint Pathway Coordinates the Division of Dikaryotic Cells in the Ink Cap Mushroom Coprinopsis cinerea

The fungal fruiting body or mushroom is a multicellular structure essential for sexual reproduction. It is composed of dikaryotic cells that contain one haploid nucleus from each mating partner sharing the same cytoplasm without undergoing nuclear fusion. In the mushroom, the pileus bears the hymenium, a layer of cells that includes the specialized basidia in which nuclear fusion, meiosis, and sporulation occur. Coprinopsis cinerea is a well-known model fungus used to study developmental processes associated with the formation of the fruiting body. Here we describe that knocking down the expression of Atr1 and Chk1, two kinases shown to be involved in the response to DNA damage in a number of eukaryotic organisms, dramatically impairs the ability to develop fruiting bodies in C. cinerea, as well as other developmental decisions such as sclerotia formation. These developmental defects correlated with the impairment in silenced strains to sustain an appropriated dikaryotic cell cycle. Dikaryotic cells in which chk1 or atr1 genes were silenced displayed a higher level of asynchronous mitosis and as a consequence aberrant cells carrying an unbalanced dose of nuclei. Since fruiting body initiation is dependent on the balanced mating-type regulator doses present in the dikaryon, we believe that the observed developmental defects were a consequence of the impaired cell cycle in the dikaryon. Our results suggest a connection between the DNA damage response cascade, cell cycle regulation, and developmental processes in this fungus.     

Effects of land preparation and maize cultivar on efficiency of N-fertilizer applied at different times and by different methods in maize—mungbean association using15N

Summary A field experiment was conducted using¹⁵N-labelled urea on a Reddish Brown Lateritic (Peleustult) soil. Growing two crops on flat land and on soil ridges of 15 cm height produced similar comparative effects from fertilizer on maize. However, fertilizer applied by broadcasting on maize with a 50 cm effective band followed by incorporating was more useful to mungbean than that applied by banding below the cereal seed rows when crops were grown on flat land. The reverse was observed when crops were grown on ridges. It was deduced that the maize cultivar was not likely to affect comparative efficiencies of fertilizer. For fertilizer application at sowing, broadcasting in 50 cm maize effective band followed by incorporating was slightly superior to banding below maize seed rows. Side-dressing of fertilizer to maize at 4 weeks after sowing was superior to application at sowing. Evenly-split application, at sowing and at 4 weeks after sowing, was either only slightly superior or comparable to non-split application by banding below maize seed rows at sowing, depending on placement method of the first application. Soil moisture status as a possible factor rendering discrepancy in the comparative efficiencies obtained by different authors is discussed.     

Mass spectrometry techniques for imaging and detection of metallodrugs

Undoubtedly, metallomic approaches based on mass spectrometry have evolved into essential tools supporting the drug development of novel metal-based anticancer drugs. This article will comment on the state-of-the-art instrumentation and highlight some of the recent analytical advances beyond routine, especially focusing on the latest developments in inductively coupled plasma-mass spectrometry (ICP-MS). Mass spectrometry-based bioimaging and single-cell methods will be presented, paving the way to exciting investigations of metal-based anticancer drugs in heterogeneous and structurally, as well as functionally complex solid tumor tissues.     

Autumnal moth – why autumnal?

1. As for some other spring‐feeding moths, adult flight of Epirrita autumnata (Lepidoptera: Geometridae) occurs in late autumn. Late‐season flight is a result of a prolonged pupal period. Potential evolutionary explanations for this phenological pattern are evaluated. 2. In a laboratory rearing, there was a weak correlation between pupation date and the time of adult emergence. A substantial genetic difference in pupal period was found between two geographic populations. Adaptive evolution of eclosion time can thus be expected. 3. Metabolic costs of a prolonged pupal period were found to be moderate but still of some ecological significance. Pupal mortality is likely to form the main cost of the prolonged pupal period. 4. Mortality rates of adults, exposed in the field, showed a declining temporal trend from late summer to normal eclosion time in autumn. Lower predation pressure on adults may constitute the decisive selective advantage of late‐season flight. It is suggested that ants, not birds, were the main predators responsible for the temporal trend. 5. Egg mortality was estimated to be low; it is thus unlikely that the late adult period is selected for to reduce the time during which eggs are exposed to predators. 6. In a laboratory experiment, oviposition success was maximal at the time of actual flight peak of E. autumnata, however penalties resulting from sub‐optimal timing of oviposition remained limited.     

Les Pseudholaster (Echinoidea,Holasteroida) du Crétacé de France

In the order of Holasteroida, the fossil record highlights a contradiction between the genus Pseudholaster that appears in the Aptian, whose plastron is prostostern close to the Jurassic ancestors and the genus Holaster, which appears in the Valanginian, whose meridostern plastron appears more derived. This inconsistency can be explained by the ignorance of the plastronal architecture on the part of the early authors. A review of the species of Pseudholaster from the Cretaceous period of France was therefore carried out. The objective was to statistically determine the discriminating morphological characters, and to study the modifications of the architecture of the interambulacrum 5 of the French species belonging to this genus, as well as to the species included in the genus Holaster incorrectly by earlier authors. This review of the species of the genus Pseudholaster begins with a study of the ontogeny of the species Holaster intermedius Münster in Goldfuss, 1826–1833, first representative of the genus Pseudholaster, which appears in the Hauterivian in the Parisian and Rhodano-vocontian basins. The modifications during growth concern the overall shape, but also the plastron architecture: the number of plastron plates increases while the number of plates located between the peristome and the periproct remains fixed. The plastron of this species is protosternal and not meridosternal as Lambert pointed out. The labrum is cupuliform in contact with the second sternal 5a2 by a narrow digitation. However, this arrangement differs from that observed on a protosternal breastplate. This apomorphism of the plastron plate pattern, called “labrotaxienne”, is found in all the Pseudholaster studied, and the study of the architecture of the interambulacrum 5 also reveals a gradual decrease in the number of preanal plates between the oldest (Hauterivian) and the younger (Cenomanian-Lower Turonian) species studied. Most of the French species have been revised, with some synonyms. A new species, P. neraudeaui, is the last known Pseudholaster dated from the upper Cenomanian and lower Turonian of southwestern France. Our study illustrates the evolution of the genus Pseudholaster between the Hauterivian and the early Turonian in France. The interest of the study is to show that the appearance of the genus Pseudholaster is older than that of the genus Holaster. Pseuholaster intermedius, of Hauterivian age, possesses a derived protostern plastron called here “labrotaxien” and not meridostern as defined historically by Lambert, and to reveal that the number of preanals decreases over geological time. This data is essential for future phylogenetic studies. On a palaeobiogeographical level, the study reveals the expansion of the genus Pseudholaster during early Cretaceous in western Europe, with diversification during the Albian, its disappearance during late Cenomanian in the Paris basin while it still persists in the Aquitain basin, its predilection for circalitoral environments.