Sarcophaga (Liosarcophaga) tibialis Macquart 1851 (Diptera: Sarcophagidae): micromorphology of preimaginal stages of a fly of medical and veterinary interest.

Sarcophagids are a large family of Diptera, with a worldwide distribution. They are related to decomposing organic matter and are very interesting for health science and in forensic cases since many species produce myiasis and occur in human corpses. This family is considered difficult to study, particularly with regard to their immature stages, to which little attention has been paid. Genus Sarcophaga Meigen, 1826 is composed of species of very similar morphology, making very difficult to distinguish. Knowledge of the immature stages of this genus is important because such stages occupy the greater part of the life cycle, so that establishing a basis for their identification will increase their usefulness in systematic and applied sciences. This contribution presents a detailed study of the morphological features, both external and internal, of the preimaginal stages of Sarcophaga (Liosarcophaga) tibialis Macquart, 1851, providing a taxonomical context for the correct identification of Liosarcophaga species of forensic interest in the Iberian Peninsula. Both light and scanning electron microscopy were applied. Complete descriptions of every stage are provided and illustrated, and their usefulness for species comparison, taking into account our uneven knowledge of morphologically immature stages of this subgenus, is indicated. Features of the cephalopharyngeal skeleton, such as the shape of the mouth hook and the intermediate and basal sclerites, and external morphology, such as the pattern of spinose band and anterior and posterior spiracles, proved useful for separating species. Finally, tentative identification keys based on light microscopy observation to distinguish S. (L.) tibialis from other species of forensic interest belonging to Liosarcophaga subgenus are proposed for every immature stage.

Occurrence and enrichment of 'bacterial sherpas': climb to sustainability in wastewater treatment.

The paper presents research on hemoglobin (Hb)-expressing bacteria in biological wastewater treatment systems. The outcome(s) will greatly reduce the aeration needs of wastewater treatment plants (WWTPs) and provide insight into emerging biological nitrogen removal processes using low dissolved oxygen (DO) conditions. In anthropogenic terms, the bacteria that express Hb could be considered as 'bacterial sherpas' that can function under low DO conditions. Hitherto, this functionality of bacteria has not been realized due to the initial response of the aerobic treatment stage: namely, morphology change by bacteria to filamentous forms to overcome oxygen mass transfer limitations causing bulking/foaming and nitrification inhibition. There is evidence, however, of the potential expression of Hb proteins by activated sludge (AS) bacteria. First, bacteria known to possess genes coding Hb proteins have been isolated from AS systems. Secondly, there is evidence that WWTPs are able to operate their biological processes at low DO without sludge bulking or incomplete nitrification. Our research has focused on nitrifying systems and has shown that this is due to prolonged operation at low DO conditions (0.1 mg O2/L), which allows sufficient time for bacterial acclimation. Additionally, it has been shown that enhanced Hb expression is linked to acclimation to low DO conditions.

Discrimination of Diptera order insects based on their saturated cuticular hydrocarbon content using a new microextraction procedure and chromatographic analysis.

The nature and proportions of hydrocarbons in the cuticle of insects are characteristic of the species and age. Chemical analysis of cuticular hydrocarbons allows species discrimination, which is of great interest in the forensic field, where insects play a crucial role in estimating the minimum post-mortem interval. The objective of this work was the differentiation of Diptera order insects through their saturated cuticular hydrocarbon compositions (SCHCs). For this, specimens fixed in 70 : 30 ethanol : water, as recommended by the European Association for Forensic Entomology, were submitted to solid-liquid extraction followed by dispersive liquid-liquid microextraction, providing preconcentration factors up to 76 for the SCHCs. The final organic extract was analysed by gas chromatography coupled with flame ionization detection (GC-FID), and GC coupled with mass spectrometry was applied to confirm the identity of the SCHCs. The analysed samples contained linear alkanes with the number of carbon atoms in the C9-C15 and C18-C36 ranges with concentrations between 0.1 and 125 ng g-1. Chrysomya albiceps (in its larval stage) showed the highest number of analytes detected, with 21 compounds, while Lucilia sericata and Calliphora vicina the lowest, with only 3 alkanes. Non-supervised principal component analysis and supervised orthogonal partial least squares discriminant analysis were performed and an optimal model to differentiate specimens according to their species was obtained. In addition, statistically significant differences were observed in the concentrations of certain SCHCs within the same species depending on the stage of development or the growth pattern of the insect.

Ultrastructure of preimaginal stages of Piophila megastigmata McAlpine, 1978 (Diptera, Piophilidae): a fly of forensic importance.

Piophila Fallén, 1810 is a genus of small flies composed of two species: Piophila casei (P. casei ) (Linnaeus, 1758), worldwide distributed, and Piophila megastigmata (P. megastigmata ) McAlpine, 1978, recently referred in the Palaearctic Region, from the Iberian Peninsula. Both species share ecological niche and are very interesting for forensic purposes, since they are present in carrion in advance stages of decay and have been found to be related to human corpses. The immature stages of P. megastigmata have ever been described, so this paper gives the ultrastructural morphologies of all preimaginal stages of P. megastigmata studied by light microscopy and scanning electron microscopy (SEM). Particular attention is given to pseudocephalon features­antenna, maxillary palps, facial mask, etc.­cephalopharyngeal skeleton, anterior and posterior spiracles, tegumentary sculpturing, and anal division among others. A comparative analysis of the main distinguishing features is made in order to understand how those features evolve along the developmental process, while larvae II and III are morphologically similar to each other, the larva I shows particular features. Larvae of all stages and pupae are easily distinguishable from other Diptera of forensic importance just based on the presence of trichoid sensilla associated to respiratory slits, instead of peristigmatig tufts, as well as on thewell-known disposition of anal papillae. The shapes of both dorsal edge at the basal part of mouthhook and dorsal bridge of cephalopharyngeal skeleton, and the tegumental ornamentationmay be considered as good features to distinguish the Piophila species, especially for P. megastigmata and P. casei . At the SEM level, shape, number, and arrangement of oral combs, oral ridges, sensilla of maxillary palpus, papillae of anterior spiracle, scales of spiracular field, and posterior spiracles represent good features to distinguish P. megastigmata from P. casei, but further studies will be necessary in West-Paleartic specimens of latter species. The key for identifying third instar larvae of forensically important Piophilidae in the Iberian Peninsula has been updated to include P. megastigmata.

Reaction strategies for the enzymatic synthesis of neopentyl glycol diheptanoate.

This work describes for the first time the green synthesis of neopentyl glycol diheptanoate in a solvent-free medium via an enzymatic pathway. The process has been carried out in an open-air reactor in order to ease water removal through evaporation and shift the chemical equilibrium towards product formation. The inhibiting effect of high concentrations of heptanoic acid has been put into evidence by a reduction of initial reaction rate when esterification was performed with stoichiometric amounts of substrates. Therefore, in this work different strategies for the stepwise addition of heptanoic acid are proposed, and best results were obtained when stoichiometric quantities of acid were divided in four equal amounts and added when previous batch was consumed. Biocatalyst Novozym® 435 concentration and temperature were optimised, giving yields of 90% in neopentyl glycol diheptanoate when 7.5% (w/w) and 70 °C were used. With a remaining 7% of heptanoic acid (probably caused by the alcohol evaporation) the addition of neopentyl glycol led to a conversion of 95%. Thus, product can be used in cosmetics without further purification and can be labelled as environmentally-friendly synthesized because of its enzymatic origin.

Techno-economic evaluation and comparison of PAC-MBR and ozonation-UV revamping for organic micro-pollutants removal from urban reclaimed wastewater.

The presence of sewage-borne Organic Micro-Pollutants (OMP) in Wastewater Treatment Plants (WWTP) effluents represents an increasing concern when water is reclaimed for irrigation or even indirect potable reuse. During eighteen months, an innovative hybrid water reclamation scheme based on a Membrane Biological Reactor (MBR) enhanced with Powder Activated Carbon (PAC) was operated at pilot-scale (70 m3/d) in order to compare it with state-of-the art Wastewater Reclamation System (WWRS) also revamped with a final step of ozonation-UV. Removal of persistent OMP, water quality and treatment costs were evaluated and compared for the different treatment schemes. OMP removal efficiency results for the different schemes concluded that established technologies, such as physico-chemical and filtration systems as well as MBR, do not remove significantly (>15%) the most recalcitrant compounds. The upgrading of these two systems through the addition of ozonation-UV step and PAC dosing allowed improving average recalcitrant OMP removal to 85 ±â€¯2 and 75 ±â€¯5%, respectively. In term of costs, PAC-MBR represents an increase of 37% of costs regarding conventional systems but presents improvements of 50% reduction in space and water quality. On the other hand, ozonation requires up to a 15% increase of foot-print; nevertheless, represents lower costs and lower carbon footprint. Ozonation-UV seems to be the best option for upgrading existing facilities, while PAC-MBR should be considered when space represents a critical limitation and produced water is reused for high water quality purposes.

State of the art of produced water treatment.

Produced water (PW) is the wastewater generated when water from underground reservoirs is brought to the surface during oil or gas extraction. PW is generated in large amounts and has a complex composition, containing various toxic organic and inorganic compounds. PW is currently treated in conventional trains that include phase separators, decanters, cyclones and coarse filters in order to comply with existing regulation for discharge. These treatment trains do not achieve more restrictive limitations related to the reuse of the effluent (reinjection into extraction wells) or other beneficial uses (e.g., irrigation). Therefore, and to prevent environmental pollution, further polishing processes need to be carried out. Characterization of the PW to determine major constituents is the first step to select the optimum treatment for PW, coupled with environmental factors, economic considerations, and local regulatory framework. This review tries to provide an overview of different treatments that are being applied to polish this type of effluents. These technologies include membranes, physical, biological, thermal or chemical treatments, where special emphasis has been made on advanced oxidation processes due to the advantages offered by these processes. Commercial treatments, based on the combination, modification and improvement of simpler treatments, were also discussed.

Estimation of postmortem interval in real cases based on experimentally obtained entomological evidence.

Using the entomological evidence obtained in several forensic cases analyzed in our laboratory for comparison, we evaluated the results of an experimental study carried out in a semiurban setting to determine the structure of the sarcosaprophagous fauna from a Mediterranean region of SE Spain. In all, 18 orders of arthropods were collected. The summarized experimental results refer to the most important taxa for estimating the postmortem interval. Thus, the seasonal character of certain Diptera species, such as Phaenicia sericata, Calliphora vicina, Chrysomya albiceps and Musca domestica, is cited. Among the Coleoptera, the role of Dermestidae as a necrophagous species, and of Staphylinidae and Histeridae as necrophilous, or Cleridae, Tenebrionidae and Nitidulidae as omnivorous, as well as their appearance on the corpse, is described. Among the Hymenoptera, Formicidae were as the most abundant group, acting as omnivores and not apparently related to any particular decomposition stage. The real cases are discussed using data from the literature and the experimentally obtained results. In every case, the most relevant factors for estimating PMI are briefly discussed, mentioning, when possible, the relation with the experimental results. We confirm the significance of the experimental results because they seem to be applicable to actual forensic cases, the details of which enlarge our very little knowledge on the subject in the Iberian Peninsula. The importance of regional faunistic studies of the sarcosaprophagous arthropod community, the results of which may be applied to forensic practice, is mentioned.

Studies on seasonal arthropod succession on carrion in the southeastern Iberian Peninsula.

A global study of the sarcosaprophagous community that occurs in the southeastern Iberian Peninsula during all four seasons is made for the first time, and its diversity is described with reference to biological indices. A total of 18,179 adults and, additionally, a number of preimaginal states were collected. The results for the main arthropod groups, and their diversity are discussed in relation to the season and decompositional stages. The results provide an extensive inventory of carrion-associated arthropods. An association between decomposition stages and more representative arthropod groups is established. With respect to the biological indices applied, Margalef's index shows that the diversity of the community increases as the state of decomposition advances, while Sorenson's quantitative index shows that the greatest similarities are between spring and summer on the one hand, and fall and winter, on the other.