Accumulation of radionuclids in amphibians (<Emphasis Type="Italic">Pelophylax ridibundus</Emphasis> Pall.) in the Middle Urals

The accumulation levels of anthropogenic ⁹⁰Sr and ¹³⁴Cs and ¹³⁷Cs radionuclides in the marsh frog have been studied in the areas of the Beloyarskii water-storage reservoir (an industrial storm-water discharge channel of the nuclear power station) and the Verkhnii Tagil water-storage reservoir (the Tagil River down-stream of the dam). No significant distinction in the radionuclide accumulation (⁹⁰Sr and ¹³⁷Cs) depending on the amphibian sex and age is detected. Comparable levels of the accumulation of radionuclides in the marsh frog, when compared to the other representatives of the water ecosystem, are estimated. An assumption of the presence of some unidentified source of radioactive contamination of marsh frogs has been made; cesium-137 may be transferred from it to the Tagil River by the frogs.     

Salivary Secretion under the Influence of Bright/Dim Light Exposure in the Morning and Evening in Humans

Recent studies show that bright and dim light intensities during the daytime have important regulatory functions. Our present study was performed to evaluate the effect of exposure to different light intensities during the morning and evening on salivary secretion and its sodium concentration. The study involved 6 healthy, female volunteers who were exposed to dim light (100 lx) from 7:00 to 17:00 and to bright light (3000 lx) from 17:00 to 23:00 one day, and to bright light (3000 lx) from 7:00 to 17:00 and dim light (100 lx) from 17:00 to 23:00 on the next day. We collected salivary samples every 10 minutes during 2 hours in the morning and in the evening by means of a Lashley cup. Saliva secretion was stimulated by sweet candy. The amount of saliva secreted was significantly greater in the morning under bright light exposure, while it was significantly greater in the evening under dim light exposure. We discuss these findings in terms of changes in activity of the parasympathetic nervous system (PNS) and sympathetic (SNS) nervous system produced by exposure to different light intensities at different times of the day.     

Tithonian-Berriasian foraminiferal faunas from the Torinosu-type calcareous blocks of the southern Kanto Mountains, Japan: their implications for post-accretionary tectonics of Jurassic to Cretaceous terranes

The Torinosu-type limestones, having many lithologic characters showing their original deposition on shallow shelves, are widely distributed in the Jurassic to Cretaceous terranes of Japan. The foraminiferal faunas from the Jurassic to the lowermost Cretaceous of Japan were first revealed in the calcareous blocks of the southern Kanto Mountains. Distinguished microfaunas consist of 39 species including many marker species of the Upper Jurassic to Lower Cretaceous in Europe, West Asia, and North Africa such as Melathrokerion spirialis, Charentia evoluta, Freixialina planispiralis, Nautiloculina oolithica, Everticyclammina cf. virguliana, Haplophragmium lutzei and Pseudocyclammina lituus. These faunas suggest a Tithonian to Berriasian age of Torinosu-type limestones. They are contained in four tectonostratigraphic units (Kamiyozawa, Hikawa and Gozenyama Formations; Ogouchi Group) continuously accreted from Middle Jurassic to Late Cretaceous. The younger deposition age of Torinosu-type limestones than the accretion age (Bajocian to Bathonian) in the Kamiyozawa Formation and their older age than the accretion age of the Ogouchi Group (late Albian to middle Maastrichtian) are important to date the post-accretionary tectonics of Jurassic to Cretaceous terranes of Japan and to explain the emplacement process of Torinosu-type limestones.     

The zebrafish heart regenerates after cryoinjury-induced myocardial infarction

Background  

In humans, myocardial infarction is characterized by irreversible loss of heart tissue, which becomes replaced with a fibrous scar. By contrast, teleost fish and urodele amphibians are capable of heart regeneration after a partial amputation. However, due to the lack of a suitable infarct model, it is not known how these animals respond to myocardial infarction.     

Male castration increases adiposity via small intestinal microbial alterations

Castration of young males is widely used in the cattle industry to improve meat quality, but the mechanism linking hypogonadism and host metabolism is not clear. Here, we use metataxonomic and metabolomic approaches to evaluate the intestinal microbiota and host metabolism in male, castrated male (CtM), and female cattle. After pubescence, the CtM cattle harbor distinct ileal microbiota dominated by the family Peptostreptococcaceae and exhibit distinct serum and muscle amino acid profiles (i.e., highly abundant branched‐chain amino acids), with increased extra‐ and intramuscular fat storage. We also evaluate the causative factor(s) that underpin the alteration of the intestinal microbiota and host metabolic phenotype in response to hypogonadism. Castration of male mice phenocopies both the intestinal microbial alterations and obese‐prone metabolism observed in cattle. Antibiotic treatment and fecal microbiota transplantation experiments in a mouse model confirm that the intestinal microbial alterations associated with hypogonadism are a key contributor to the obese phenotype in the CtM animals. Collectively, targeting the gut microbiota is a potential therapeutic strategy for the treatment of both hypogonadism and obesity.     

Large granular lymphocytes are central cells in the interleukin-2-dependent differentiation pathway of natural killer cells

Peripheral blood low-density cells were sorted, with respect to their ability to accumulate the lysosomotropic agent mepacrine (Mep), into lysosome-rich (Mep+) and lysosome-poor (Mep-) cell populations. Cells of large granular lymphocyte (LGL) morphology and phenotype were found in the Mep+ but not in the Mep- cell population. The latter cells lacked any natural killer (NK) activity. Cultures of the Mep- cells resulted in the appearance of cells showing K-562 lytic activity, LGL morphology and CD16 and/or Leu-7 positivity. This process was facilitated by the supplementation of the culture with recombinant human interleukin-2 (rIL-2). Mep+ cells retested after 7 days of culture showed a decline in the fraction of granular (LGL and Mep+) cells. This decrease was less pronounced but also seen in rIL-2-supplemented cultures. In spite of the lower number of typical LGL, Mep+ cells cultured with rIL-2 were mostly large but scarcely granular; rIL-2-activated K-562 killing (rIL-2 AK) of originally Mep+ cells was much higher than K-562 lytic activity of these cells at the beginning of the culture, and as compared to rIL-2 AK of Mep- cells. From this finding it is apparent that the most active rIL-2 AK cells originate from low-density granular (Mep+) cells (LGL) and, therefore, we propose to call them 'giant' NK cells. Furthermore, in the presence of rIL-2, LGL differentiate from agranular (Mep-) low-density cells. In view of these data, LGL appear to be resting cells on the differentiation pathway of NK cells.     

A unique case of commensalism: The beaver beetle Platypsyllus castoris (Leiodidae,Coleoptera) and its morphological adaptations

Platypsyllus castoris is closely associated with beavers and displays a unique set of structural specializations. We document the morphology of adults with modern techniques, and interpret evolutionary changes linked with the specific life style. The small subfamily Platypsyllinae has evolved an entire suite of features correlated with a more or less close association with mammals, for instance a flattened body, a dorsal cephalic shield, flightlessness, eye reduction, and depigmentation. Within this small group, Platypsyllus displays numerous autapomorphic features, correlated with a close association with the beaver. Essential is a combination of mechanical stabilization and firm anchorage on the host, and efficient forward movement in the fur. Exo- and endoskeletal structures of the head and thorax are reinforced by vertical cuticular columns and by an array of internal ridges. The antennae are shortened and strongly modified, the mandibles distinctly reduced and flattened, unsuitable for cutting, scraping or grinding. The musculature of the mouthparts is simplified, whereas an enhanced set of prepharyngeal and pharyngeal dilators forms an efficient sucking pump. The prothoracic musculature is strongly developed. In contrast, the pterothoracic muscle system is distinctly simplified, even though leg muscles are strongly developed. Using the legs, the flattened beetles move sideways through the dense fur of the beaver, using posteriorly directed groups of setae and ctenidia to prevent being pushed backwards by the densely arranged hairs. In contrast to the anterior body, the cuticle of the abdomen is thin, and the entire tagma flexible, with thin layers of segmental muscles. The hind gut is not connected with the mid gut. The beetles probably consume liquid, possibly with emulgated minute skin debris. As the morphology of the mouthparts excludes damage to the skin of the host, the association should not be addressed as ectoparasitic but as commensalism.     

Pollen grains in honeys produced by Tetragonisca angustula (Latreille, 1811) (Hymenoptera: Apidae) in tropical semi-arid areas of north-eastern Brazil

The flora of north-eastern Brazil offers a source of nectariferous–polliniferous species that support many native pollinators. However, few studies have examined the plant–Meliponini interaction, especially from the melissopalynological aspect. We assessed the flora exploited by Tetragonisca angustula in two caatinga (dry vegetation) areas in the Brazilian semi-arid region through pollen analysis of honeys with the goal of answering the following questions: (a) What are the most representative pollens found in the honeys? (b) Do certain pollen types function as regional geographic markers? (c) What are the characteristics of the trophic niche of T. angustula in these areas? The honeys (n = 27) were collected every month from October 2010 to December 2011 in Itaberaba and Ruy Barbosa, diluted in tepid water and 95 % ethanol and subsequently acetolysed. The results revealed 67 pollen types in the honeys, with 25 common to both study areas and most of them belonging to the family Fabaceae (>10 types). The most frequent pollen types were Heteropterys, Mikania, Myrcia, Prosopis juliflora and Solanum for Itaberaba and Heteropterys, Mimosa tenuiflora, P. juliflora, Schinus, Senna macranthera, Solanum and Syagrus coronata for Ruy Barbosa. Anadenanthera colubrina, Poincianella pyramidalis and Ziziphus joazeiro were considered markers for caatinga flora. The amplitude of the trophic niche varied between 0.36 and 2.55, while the evenness ranged from 0.15 to 0.77, characterising the foraging habit of T. angustula as polylectic with a more homogeneous use of the flora in Ruy Barbosa than in Itaberaba.     

Design of a microaerobically inducible replicon for high-yield plasmid DNA production

A pUC-derived replicon inducible by oxygen limitation was designed and tested in fed-batch cultures of Escherichia coli. It included the addition of a second inducible copy of rnaII, the positive replication control element. The rnaII gene was expressed from P_trc and cloned into pUC18 to test the hypothesis that the ratio of the positive control molecule RNAII to the negative control element, RNAI, was the determinant of plasmid copy number per chromosome (PCN). The construct was evaluated in several E. coli strains. Evaluations of the RNAII/RNAI ratio, PCN and plasmid yield normalized to biomass (Y_pDNA/X) were performed and the initial hypothesis was probed. Furthermore, in high cell-density cultures in shake flasks, an outstanding amount of 126 mg/L of plasmid was produced. The microaerobically inducible plasmid was obtained by cloning the rnaII gene under the control of the oxygen-responsive Vitreoscilla stercoraria hemoglobin promoter. For this plasmid, but not for pUC18, the RNAII/RNAI ratio, PCN and Y_pDNA/X efficiently increased after the shift to the microaerobic regime in fed-batch cultures in a 1 L bioreactor. The Y_pDNA/X of the inducible plasmid reached 12 mg/g at the end of the fed-batch but the original pUC18 only reached ca. 6 mg/g. The proposed plasmid is a valuable alternative for the operation and scale-up of plasmid DNA production processes in which mass transfer limitations will not represent an issue.     

Identification of insect pests as food foreign materials using DNA barcodes

Insect foreign materials in food are of great economic and hygienic significance. However, identifying these species with any certainty requires an expert taxonomist and can be a time consuming process. Furthermore, insects are found as body parts or they are immature specimens that cannot be identified by conventional means. For these reasons, a reference database and efficient means of identification by non‐specialists are necessary to control insect pests. In this study, we chose 15 important insect pest species, because they had a higher probability of being included in human foods. We tested the utility of the cytochrome c oxidase I (COI) DNA barcodes for the identification. A 658‐bp fragment of the COI gene was sequenced, aligned, and a sequence data bank was constructed. As a result, the COI barcode sequence was suitable for identifying insect pests as food foreign materials. Photographs of morphological key characters by stereoscopic microscope and a pictorial key of the species are provided.