Uncommon formation of two antiparallel sperm bundles per cyst in tenebrionid beetles (Coleoptera)

Several species of Tenebrionidae are stored-grain pests. Since they belong to a specious family, the systematics of these beetles is still in doubt. In insects, spermatogenesis and the spermatozoa exhibit great diversity, and are therefore commonly used in phylogenetic and taxonomic analyses. During the spermatogenetic process in these organisms, the cells originating from a single spermatogonium develop synchronically in groups referred to as cysts. At the end of this process, there is usually only one sperm bundle per cyst, with all the cells in the same orientation. This paper details the spermiogenesis of the tenebrionid beetles Tenebrio molitor, Zophobas confusa, Tribolium castaneum and Palembus dermestoides using whole mount and histological sections of the cysts. In these species, spermatogenesis is similar to that which occurs in most insects. However, during spermiogenesis, the nuclei of the spermatids migrate to two opposite regions at the periphery of the cyst, leading to the uncommon formation of two bundles of spermatozoa per cyst. This feature is possibly an apomorphy for Tenebrionidae.     

Spatial Variability of Nitrate Concentrations Under Diverse Conditions in Tributaries to a Lake Watershed1

Abstract: Nitrate‐nitrogen (NO₃‐N) concentrations in stream water often respond uniquely to changes in inter‐annual conditions (e.g., biological N uptake and precipitation) in individual catchments. In this paper, we assess (1) how the spatial distribution of NO₃‐N concentrations varies across a dense network of nonnested catchments and (2) how relationships between multiple landscape factors [within whole catchments and hydrologically sensitive areas (HSAs) of the catchments] and stream NO₃‐N are expressed under a variety of annual conditions. Stream NO₃‐N data were collected during two synoptic sampling events across >55 tributaries and two synoptic sampling periods with >11 tributaries during summer low flow periods. Sample tributaries drain mixed land cover watersheds ranging in size from 0.150 to 312 km² and outlet directly to Cayuga Lake, New York. Changes in NO₃‐N concentration ratios between each sampling event suggest a high degree of spatial heterogeneity in catchment response across the Cayuga Lake Watershed, ranging from 0.230 to 61.4. Variations in NO₃‐N concentrations within each of the large synoptic sampling events were also high, ranging from 0.040 to 8.7 mg NO₃‐N/l (March) and 0.090 to 15.5 mg NO₃‐N/l (October). Although Pearson correlation coefficients suggest that this variability is related to multiple landscape factors during all four sampling events, partial correlations suggest percentage of row crops in the catchments as the only similar factor in March and October and catchment area as the only factor during summer low flows. Further, the strength of the relationships is typically lower in the HSAs of catchment. Advancing current understanding of such variations and relationships to landscape factors across multiple catchments – and under a variety of biogeochemical and hydrological conditions – is important, as (1) nitrate continues to be employed as an indicator of regional aquatic ecosystem health and services and (2) a unified framework approach for understanding individual catchment processes is a rapidly evolving focus for catchment‐based science and management.     

Pathways towards large-scale implementation of CO2 capture and storage: A case study for the Netherlands

We sketch four possible pathways how carbon dioxide capture and storage (CCS) (r)evolution may occur in the Netherlands, after which the implications in terms of CO₂ stored and avoided, costs and infrastructural requirements are quantified. CCS may play a significant role in decarbonising the Dutch energy and industrial sector, which currently emits nearly 100 Mt CO₂/year. We found that 15 Mt CO₂ could be avoided annually by 2020, provided some of the larger gas fields that become available the coming decade could be used for CO₂ storage. Halfway this century, the mitigation potential of CCS in the power sector, industry and transport fuel production is estimated at maximally 80–110 Mt CO₂/year, of which 60–80 Mt CO₂/year may be avoided at costs between 15 and 40 €/t CO₂, including transport and storage. Avoiding 30–60 Mt CO₂/year by means of CCS is considered realistic given the storage potential represented by Dutch gas fields, although it requires planning to assure that domestic storage capacity could be used for CO₂ storage. In an aggressive climate policy, avoiding another 50 Mt CO₂/year may be possible provided that nearly all capture opportunities that occur are taken. Storing such large amounts of CO₂ would only be possible if the Groningen gas field or large reservoirs in the British or Norwegian part of the North Sea will become available.     

Effect of impeller type and mechanical agitation on the mass transfer and power consumption aspects of ASBR operation treating synthetic wastewater

The effect of flow type and rotor speed was investigated in a round-bottom reactor with 5 L useful volume containing 2.0 L of granular biomass. The reactor treated 2.0 L of synthetic wastewater with a concentration of 800 mgCOD/L in 8-h cycles at 30 degrees C. Five impellers, commonly used in biological processes, have been employed to this end, namely: a turbine and a paddle impeller with six-vertical-flat-blades, a turbine and a paddle impeller with six-45 degrees -inclined-flat-blades and a three-blade-helix impeller. Results showed that altering impeller type and rotor speed did not significantly affect system stability and performance. Average organic matter removal efficiency was about 84% for filtered samples, total volatile acids concentration was below 20 mgHAc/L and bicarbonate alkalinity a little less than 400 mgCaCO3/L for most of the investigated conditions. However, analysis of the first-order kinetic model constants showed that alteration in rotor speed resulted in an increase in the values of the kinetic constants (for instance, from 0.57 h(-1) at 50 rpm to 0.84 h(-1) at 75 rpm when the paddle impeller with six-45 degrees -inclined-flat-blades was used) and that axial flow in mechanically stirred reactors is preferable over radial-flow when the vertical-flat-blade impeller is compared to the inclined-flat-blade impeller (for instance at 75 rpm, from 0.52 h(-1) with the six-flat-blade-paddle impeller to 0.84 h(-1) with the six-45 degrees -inclined-flat-blade-paddle impeller), demonstrating that there is a rotor speed and an impeller type that maximize solid-liquid mass transfer in the reaction medium. Furthermore, power consumption studies in this reduced reactor volume showed that no high power transfer is required to improve mass transfer (less than 0.6 kW/10(3)m3).     

Insecticide residues in soil and water in coastal areas of vegetable production in Togo

Some common organochlorine, organophosphorus and pyrethroid insecticides were analysed in agricultural soil samples (n?=?35) and surface water and groundwater samples (n?=?25) collected from coastal areas of vegetable production in Togo. Analytical methods included solvent extraction of the insecticide residues and their subsequent quantification using GC-ECD. δ-HCH, heptachlor epoxide, 4,4-DDE, endosulphan (α, β and sulphate), lambda-cyalothrin and chlorpyrifos were found in the soil samples with concentrations that varied from non-detectable (ND) to 26.93 μg kg^?1 dry weight. For water samples, heptachlor epoxide, 2,4-DDD, 4,4-DDD, 4,4-DDE and endosulphan (α, β, and sulphate) were found at contamination levels that varied from ND to 0.116 μg L^?1. The concentration of insecticide residues detected in the water samples was below the limits set by the World Health Organization (WHO) and also by the European Union (EU), with the exception of the concentration of endosulphan sulphate at the Aného site, which was 0.116 μg L^?1.     

Assessment of trace metals and porphyrins in excreta of Humboldt penguins (Spheniscus humboldti) in different locations of the northern coast of Chile

To add data on trace metal contamination of Humboldt penguins in the South Pacific, levels of trace metals (As, Hg, Pb, Cu, Zn, and Cd) and porphyrins (copro-, uro-, and proto-) in excreta of Humboldt penguins that inhabit some important nesting sites on the northern coast of Chile were determined. Fresh excreta were collected on Pan de Azúcar Island, Chañaral Island, and Cachagua Island, from December 2011 to January 2012. Concentration of metals was determined by flame atomic absorption spectrophotometry, whereas porphyrins levels were measured by fluorimetric analysis. Concentrations (dry weight) of Cu (199.67 μg g^?1), As (7.85 μg g^?1), and Pb (12.78 μg g^?1) were higher (p?≤?0.05) in Cachagua Island. Colonies from Pan de Azúcar Island showed the highest levels of Hg (0.76 μg g^?1), Cd (47.70 μg g^?1), and Zn (487.10 μg g^?1). Samples from Cachagua Island showed the highest (p?≤?0.05) levels of copro- (2.16 nmol g^?1), uro- (2.20 nmol g^?1), and protoporphyrins (2.23 nmol g^?1). There was a positive correlation between the metals As, Pb, and Cu with uro-, copro-, and protoporphyrins. The results indicated that penguin colonies from Cachagua Island are more exposed to metal contamination than penguin colonies from Pan de Azúcar and Chañaral Islands, thus being more likely to develop certain diseases caused by contamination with metals. Considering biomagnification, the metals detected in the excreta of Humboldt penguins can be a source of contamination from marine environments to terrestrial ecosystems, which could also affect other living organisms.     

Impact of chronic exposure to low doses of chlorpyrifos on the intestinal microbiota in the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®) and in the rat

The impact of the insecticide chlorpyrifos (CPF) on the mammalian digestive system has been poorly described. The present study aimed at evaluating the effect of chronic, low-dose exposure to CPF on the composition of the gut microbiota in a Simulator of the Human Intestinal Microbial Ecosystem: the SHIME® and in rats. The SHIME® comprises six reactor vessels (stomach to colon). The colonic segments were inoculated with feces from healthy humans. Then, the simulator was exposed to a daily dose of 1 mg of CPF for 30 days. The changes over time in the populations of bacteria were examined at different time points: prior to pesticide exposure (as a control) and after exposure. In parallel, pregnant rats were gavaged daily with 1 mg/kg of CPF (or vehicle) until the pups were weaned. Next, the rats were gavaged with same dose of CPF until 60 days of age (adulthood). Then, samples of different parts of the digestive tract were collected under sterile conditions for microbiological assessment. Chronic, low-dose exposure to CPF in the SHIME® and in the rat was found to induce dysbiosis in the microbial community with, in particular, proliferation of subpopulations of some strains and a decrease in the numbers of others bacteria. In compliance with European guidelines, the use of the SHIME® in vitro tool would help to (1) elucidate the final health effect of toxic agents and (2) minimize (though not fully replace) animal testing. Indeed, certain parameters would still have to be studied further in vivo.     

Distribution coefficients of potentially toxic elements in soils from the eastern Amazon

The solid-solution distribution or partition coefficient (Kd) is a measure of affinity of potentially toxic elements (PTE) for soil colloids. Kd plays a key role in several models for defining PTE guideline values in soils and for assessing environmental risks, and its value depends on edaphic and climatic conditions of the sites where the soils occur. This study quantified Kd values for Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn from representative soil samples from Brazil’s eastern Amazon region, which measures 1.2 million km². The Kd values obtained were lower than those set by both international and Brazilian environmental agencies and were correlated with the pH, Fe and Mn oxide content, and cationic exchange capacity of the soils. The following order of decreasing affinity was observed: Pb?>?Cu?>?Hg?>?Cr?>?Cd?≈?Co?>?Ni?>?Zn.     

Protective role of a methanolic extract of spinach (Spinacia oleracea L.) against Pb toxicity in wheat (Triticum aestivum L.) seedlings: beneficial effects for a plant of a nutraceutical used with animals

Spinach extracts contain powerful natural antioxidants and have been used to improve the response of animal cells to various stress factors. The aim of the present study was to assess the effects of a methanolic extract of spinach (SE) used at two concentrations (21.7 and 217 ppm) on the growth, certain enzymes and antioxidant systems in wheat seedlings under lead stress. When wheat seedlings were grown for 7 days in a solution containing Pb(NO₃)₂ (3 mM), germination and growth were impaired, while signs of oxidative stress were observed. SE (217 ppm) pretreatment was able to protect seedlings from Pb toxicity by both reducing Pb uptake and Pb-induced oxidative stress. As a consequence, almost normal germination, elongation, biomass and α-amylase activity were restored by SE (217 ppm) pretreatment of wheat seedlings, in spite of the presence of Pb. Our results support the protective role and the antioxidant effect of SE against Pb. These results show an amazing similarity to the effects of SE in animals, which suggests that providing “nutraceuticals” to plants could improve their “health” status.     

Tobacco Plants Detect a Decrease of Environmental Genotoxicity in Toulouse (France)

Tobacco plants, heterozygous for two independent loci involved in the chlorophyll parenchyma differentiation, allow the genotoxic effects of the atmosphere of the industrial estate South of Toulouse to be estimated. Somatic spots of green cellular colonies on yellow-green background, were counted to calculate the cellular rates of reversion. Two experiments were carried out in 1981, and in 1997. A general decrease of genotoxic effects was observed. These observations were interpreted as being due to a general decrease of the air pollution evaluated by the development of the concentrations of three toxic gases before and after the implementation of cleanup devices. The results obtained demonstrate the efficiency of this bio-indicator, which is easy to use and capable of integrating, in situ, genotoxic variations throughout the duration of plants' growth.