Chilled Galleria mellonella larvae: mechanism of supernumerary moulting

ABSTRACT. Supernumerary larval instars were produced when Galleria mellonella L. (Lepidoptera) larvae were chilled at 0°C. Although sensitivity to cooling stress of the last instar and younger larvae were generally the same, only penultimate and the last instar larvae showed a significant correlation between their age and the number of additional larval moults. Chilling stress induced a rapid and persistent increase in the JH titre of the last instar larvae. Severing the ventral nerve cord resulted in a predictable loss of the ability to produce supernumerary moults in chilled last instar larvae. The data suggest that sensory input stimulates allatotropic hormone secretion by the brain of chilled larvae. The possible mechanism controlling supernumerary moulting is discussed.     

Serotonin modulates a photic response in circadian locomotor rhythmicity of adults of the blow fly, Calliphora vicina

Abstract. The present experiments were undertaken to explore a role for serotonin (5-hydroxytryptamine, 5-HT) in modulating photic signal transduction in photoreceptors of the blow fly, Calliphora vicina. Injection of p-chlorophenylalanine (pCPA) into the haemolymph appeared to reduce sensitivity to the photic effects of constant ‘bright’ light (LL hyperactivity and circadian arrhythmicity). After drug injection in bright LL, flies continued with a free-running rhythm as in constant darkness (DD) or with a lengthened period τ as in ‘dim’ LL. When 5-HT was injected into flies kept in dim LL, they became hyperactive and arrhythmic as in bright LL. This finding suggests a potential role for serotonin as mediator of circadian changes in the insect visual system including extraretinal photoreceptors.     

A new genus and species of scorpionfly (Mecoptera) from Baltic amber,with an unusually developed postnotal organ

A new genus and species of fossil scorpionflies (Mecoptera) Baltipanorpa damzeni gen. et sp.n. is described from two well‐preserved male specimens in Baltic amber (middle Eocene: Lutetian). The most characteristic feature of the new taxon is an unusually developed postnotal organ on abdominal tergum IV. This is the most extremely developed example of this organ among Mecoptera and the only observation of notal and postnotal organs among fossil scorpionflies. The following combination of characters are provided to distinguish the new genus from other Panorpidae: Sc, short; R₁ and R₂ two‐branched; A₁ joins posterior margin of wing only at same level as fork of vein Rs; unusual shape of abdomen, abdominal segments I–IV strongly reduced, abdominal segment V elongate and widened, segments VII and VIII strongly elongate; notal and postnotal organs present, strongly developed process (postnotal organ) on tergum IV, unknown in all described extant and fossil scorpionflies. Different types of notal organs of Mecoptera are compared and their function and morphology are discussed. Morphological analysis of notal and postnotal organs in extant species permits us to conclude that B. damzeni sp.n. is characterized by the most developed and complex notal organs in all Mecoptera.     

PHYTOALEXIN DEFICIENT 4 affects reactive oxygen species metabolism,cell wall and wood properties in hybrid aspen (Populus tremula L. × tremuloides)

The PHYTOALEXIN DEFICIENT 4 (PAD4) gene in Arabidopsis thaliana (AtPAD4) is involved in the regulation of plant – pathogen interactions. The role of PAD4 in woody plants is not known; therefore, we characterized its function in hybrid aspen and its role in reactive oxygen species (ROS)‐dependent signalling and wood development. Three independent transgenic lines with different suppression levels of poplar PAD expression were generated. All these lines displayed deregulated ROS metabolism, which was manifested by an increased H₂O₂ level in the leaves and shoots, and higher activities of manganese superoxide dismutase (MnSOD) and catalase (CAT) in the leaves in comparison to the wild‐type plants. However, no changes in non‐photochemical quenching (NPQ) between the transgenic lines and wild type were observed in the leaves. Moreover, changes in the ROS metabolism in the pad4 transgenic lines positively correlated with wood formation. A higher rate of cell division, decreased tracheid average size and numbers, and increased cell wall thickness were observed. The results presented here suggest that the Populus tremula × tremuloides PAD gene might be involved in the regulation of cellular ROS homeostasis and in the cell division – cell death balance that is associated with wood development.     

Tuberculosis is associated with expansion of a motile,permissive and immunomodulatory CD16+ monocyte population via the IL-10/STAT3 axis

The human CD14⁺ monocyte compartment is composed by two subsets based on CD16 expression. We previously reported that this compartment is perturbed in tuberculosis (TB) patients, as reflected by the expansion of CD16⁺ monocytes along with disease severity. Whether this unbalance is beneficial or detrimental to host defense remains to be elucidated. Here in the context of active TB, we demonstrate that human monocytes are predisposed to differentiate towards an anti-inflammatory (M2-like) macrophage activation program characterized by the CD16⁺CD163⁺MerTK⁺pSTAT3⁺ phenotype and functional properties such as enhanced protease-dependent motility, pathogen permissivity and immunomodulation. This process is dependent on STAT3 activation, and loss-of-function experiments point towards a detrimental role in host defense against TB. Importantly, we provide a critical correlation between the abundance of the CD16⁺CD163⁺MerTK⁺pSTAT3⁺ cells and the progression of the disease either at the local level in a non-human primate tuberculous granuloma context, or at the systemic level through the detection of the soluble form of CD163 in human sera. Collectively, this study argues for the pathogenic role of the CD16⁺CD163⁺MerTK⁺pSTAT3⁺ monocyte-to-macrophage differentiation program and its potential as a target for TB therapy, and promotes the detection of circulating CD163 as a potential biomarker for disease progression and monitoring of treatment efficacy.     

Correlations between genetic variance and adiposity measures,and gene × gene interactions for obesity in postmenopausal Vietnamese women

Although environmental factors are important, there is considerable evidence that genes also have a significant role in the pathogenesis of obesity. We conducted a population-based study to investigate the relationship between candidate genes for obesity (UCP1, UCP2, ADRA2B, ADRB3, LEPR, VDR and ESR1) and adiposity measures (body mass index, body fat percentage, weight, waist circumference and waist–hip ratio) in terms of individual gene and gene × gene interaction in models unadjusted and adjusted for covariates (age, years since menopause, educational level and total energy intake). Postmenopausal women with TC genotype of ESR1 gene had higher body fat percentage than those with TT genotype in the models unadjusted and adjusted for the covariates (P = 0.006 in adjusted model). In multiple logistic regression analysis, BsmI and ApaI SNPs of VDR genes were significantly associated with overweight and obesity. The UCP2–VDR ApaI interaction to susceptibility of overweight and obesity was first observed from logistic regression analysis, and then confirmed in the multifactor dimensionality reduction method unadjusted and adjusted for the covariates. This interaction had 69.09% prediction accuracy for overweight and obesity (P = 0.001, sign test). In conclusion, the study suggests the significant association of ESR1 and VDR genes with adiposity measures and the UCP2–VDR ApaI interaction to susceptibility to being overweight and obesity in postmenopausal Vietnamese women.     

Bite traces on dicynodont bones and the early evolution of large terrestrial predators

Nied?wiedzki, G., Gorzelak, P. & Sulej, T. 2010: Bite traces on dicynodont bones and the early evolution of large terrestrial predators. Lethaia, Vol. 44, pp. 87–92. Dicynodont (Synapsida: Anomodontia) bones from the Late Triassic (late Norian/early Rhaetian) of Poland yield characteristic tooth marks that can be attributed to three ichnotaxa (Linichnus serratus, Knethichnus parallelum and Nihilichnus nihilicus). The general shape and dimension of these traces perfectly match the dental morphology of a co‐occurring carnivorous dinosaur. It is therefore concluded that early carnivorous dinosaurs were feeding on dicynodonts. This discovery constitutes one of the oldest evidence of dinosaur predator–prey interaction. It is suggested that an evolutionary increase in the size of dicynodonts across the Late Triassic may have been driven by selection pressure to reach a size refuge from early dinosaur predators. □Bite traces, dicynodonts, dinosaurs, predation, Triassic.     

Early Cretaceous record of microboring organisms in skeletons of growing corals

Ko?odziej, B., Golubic, S., Bucur, I.I., Radtke, G. & Tribollet, A. 2011: Early Cretaceous record of microboring organisms in skeletons of growing corals. Lethaia, Vol. 45, pp. 34–45. A spectacularly preserved assemblage of microbial euendoliths, penetrating into skeletons of growing scleractinian corals, has been recognized in Early Aptian (Early Cretaceous) reef limestone of the Rar?u Mountains (East Carpathians, NE Romania). Microboring euendolithic filaments were found in five coral colonies of the suborder Microsolenina. They remained in part well‐preserved, often impregnated with iron oxides, which made them visible even in strongly recrystallized parts of coral skeletons. Filaments of a wide range of sizes (2–40 μm in diameter) were concentrated within medium parts of coral septa, oriented along the septa in the direction of the coral growth. The larger filaments were tubular, occurring in bundles and branched into finer, often tapering branches. Their behaviour and organization were quite similar to the modern euendolithic siphonalean chlorophyte Ostreobium. Filament diameters exceeded those reported for the modern species, but covered a similarly wide size range. Narrower frequently branching filaments, 4–8 μm in diameter, resemble distal branching patterns of modern Ostreobium quekettii. Some very thin filaments (ca. 1–2 μm) observed within skeleton or inside the large tubular filaments, sometimes associated with globular swellings, may represent euendolithic fungi. The recrystallization of coral skeleton had limited effect on preservation of euendoliths due to their impregnation with iron oxides; microbial euendoliths were subjected to different taphonomic changes. □Chlorophytes, Early Cretaceous, fungi, microbial euendoliths, Romania, scleractinian corals.