Mites as biological tags of their hosts

Movements and spatial distribution of host populations are expected to shape the genetic structure of their parasite populations. Comparing the genetic patterns of both interacting species may improve our understanding of their evolutionary history. Moreover, genetic analyses of parasites with horizontal transmission may serve as indicators of historical events or current demographic processes that are not apparent in the genetic signature of their hosts. Here, we compared mitochondrial variation in populations of the ectoparasitic mite Spinturnix myoti with the genetic pattern of its host, the Maghrebian bat Myotis punicus in North Africa and in the islands of Corsica and Sardinia. Mite mitochondrial differentiation among populations was correlated with both host mitochondrial and nuclear differentiation, suggesting spatial co‐differentiation of the lineages of the two interacting species. Therefore our results suggest that parasite dispersal is exclusively mediated by host movements, with open water between landmasses as a main barrier for host and parasite dispersal. Surprisingly the unique presence of a continental European mite lineage in Corsica was inconsistent with host phylogeographical history and strongly suggests the former presence of European mouse‐eared bats on this island. Parasites may thus act as biological tags to reveal the presence of their now locally extinct host.     

Analysis of Tubespins as a suitable scale‐down model of bioreactors for high cell density CHO cell culture

High cell density (HCD) culture increases recombinant protein productivity via higher biomass. Compared to traditional fed‐batch cultures, HCD is achieved by increased nutrient availability and removal of undesired metabolic components via regular medium replenishment. HCD process development is usually performed in instrumented lab‐scale bioreactors (BR) that require time and labor for setup and operation. To potentially minimize resources and cost during HCD experiments, we evaluated a 2‐week 50‐mL Tubespin (TS) simulated HCD process where daily medium exchanges mimic the medium replacement rate in BR. To best assess performance differences, we cultured 13 different CHO cell lines in simulated HCD as satellites from simultaneous BR, and compared growth, metabolism, productivity and product quality. Overall, viability, cell‐specific productivity and metabolism in TS were comparable to BR, but TS cell growth and final titer were lower by 25 and 15% in average, respectively. Peak viable cell densities were lower in TS than BR as a potential consequence of lower pH, different medium exchange strategy and dissolved oxygen limitations. Product quality attributes highly dependent on intrinsic molecule or cell line characteristics (e.g., galactosylation, afucosylation, aggregation) were comparable in both scales. However, product quality attributes that can change extracellularly as a function of incubation time (e.g., deamidation, C‐terminal lysine, fragmentation) were in general lower in TS because of shorter residence time than HCD BR. Our characterization results and two case studies show that TS‐simulated HCD cultures can be effectively used as a simple scale‐down model for relative comparisons among cell lines for growth or productivity (e.g., clone screening), and for investigating effects on protein galactosylation. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:490–499, 2017     

The taste of polycose in hamsters

Hamsters show a preference for Polycose, a mixture of starch-derived glucose polymers, that is as strong as their preference for sucrose. However, in the hamster, taste aversions to Polycose may be less easily acquired than taste aversions to sucrose and the qualitative aspects of Polycose are unknown in this species. In order to examine the taste of Polycose in the hamster, we utilized a taste-aversion protocol with two conditioning trials. Animals were trained to avoid one of three different conditioning stimuli: 50 mM sucrose, 100 mM Polycose and a mixture of 50 mM sucrose with 100 mM Polycose. Control animals were conditioned with deionized water. After the second conditioning trial, generalization testing began for the three conditioning stimuli plus 3 mM citric acid, 300 mM KCI and 30 mM NaCl. The results showed that aversions to Polycose, sucrose or the Polycose/sucrose mixture cross- generalized, demonstrating that Polycose and sucrose share a common taste percept in the hamster. None of the aversions generalized to NaCl, citric acid or KCI. In addition, comparisons among the patterns of taste generalizations indicated that the tastes of Polycose and sucrose also had distinct qualitative components. Finally, although the taste of 100 mM Polycose was more salient than the taste of 50 mM sucrose, the taste of sucrose could still be detected in a mixture with Polycose.      

Molecular phylogeny of the genus Tibicina (Hemiptera, Cicadidae): rapid radiation and acoustic behaviour

To estimate the potential contribution of ethological and ecological parameters to the mechanisms of species formation and species isolation in the Palearctic cicada genus Tibicina , we constructed a molecular phylogenetic hypothesis of extant Tibicina species. Seven mitochondrial genes and a fragment of a nuclear gene were sequenced (3046 bp). Mitochondrial genes included 547 informative sites but the nuclear gene was too conserved to be included in the analysis. The tree was characterized by a basal polytomy indicating that Tibicina species arose rapidly. Such rapid radiation might explain the low divergence in the acoustic communication observed between species. Parameters describing habitat selection and acoustic communication were mapped onto the tree. A shift in habitat selection accompanied by acoustic changes might have contributed to one speciation event. The stochastic distribution of the same acoustic characters on the other branches of the tree implies, however, that the subtle acoustic differences between species could be the result of previous speciation events and independent evolutionary histories, rather than having contributed themselves in the speciation and isolation processes.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 611–626.     

The relationship of aerobic capacity,anaerobic peak power and experience to performance in CrossFit exercise

CrossFit is becoming increasingly popular as a method to increase fitness and as a competitive sport in both the Unites States and Europe. However, little research on this mode of exercise has been performed to date. The purpose of the present investigation involving experienced CrossFit athletes and naïve healthy young men was to investigate the relationship of aerobic capacity and anaerobic power to performance in two representative CrossFit workouts: the first workout was 12 minutes in duration, and the second was based on the total time to complete the prescribed exercise. The participants were 32 healthy adult males, who were either naïve to CrossFit exercise or had competed in CrossFit competitions. Linear regression was undertaken to predict performance on the first workout (time) with age, group (naïve or CrossFit athlete), VO₂max and anaerobic power, which were all significant predictors (p < 0.05) in the model. The second workout (repetitions), when examined similarly using regression, only resulted in CrossFit experience as a significant predictor (p < 0.05). The results of the study suggest that a history of participation in CrossFit competition is a key component of performance in CrossFit workouts which are representative of those performed in CrossFit, and that, in at least one these workouts, aerobic capacity and anaerobic power are associated with success.     

Two new species of Agatea (Violaceae) endemic to New Caledonia, with some taxonomic notes and a key to New Caledonian species

While working on a treatment of Violaceae for the Flore de Nouvelle-Caledonie et dependences , two new species were recognized, Agatea veillonii Munzinger and A. lecointei Munzinger. These species are here described and illustrated. Some taxonomic notes and a regional identification key are provided.     

Theory and practice of combining coagulant fixation and microwave histoprocessing

The German, F. Blum, introduced formalin as a fixative in 1893. Formalin rapidly became popular for hardening and preserving gross human and animal specimens. As a result, microscopy for diagnostic pathology by combining paraffin embedding and formalin fixation was developed. Alcohol-based fixatives have coagulation of proteins as their main preservative effect. Because there is no cross-linking, immunostaining is not compromised, and DNA and RNA is not damaged. Ethyl alcohol was used by Dutch scientists of the 18th century, but was replaced by the cheaper formalin. Addition of low molecular weight polyethylene glycol (PEG) optimized the coagulant fixative, Kryofix. The polyethylene glycol prevents excessive hardening and enhances the speed of coagulation of proteins. Kryofix was used on a large scale for skin biopsies in Leiden between 1987 and 2001. DNA preservation by the formulated coagulant fixative, BoonFix, is related to the concentration of ethyl alcohol, PEG and acetic acid. BoonFix has been used since 2004 in Leiden for over 40,000 diagnostic skin biopsies and more than 100,000 cervical samples. A literature review and three decades of experience with coagulant, formalin-free fixatives in pathology suggest that when health authorities realize that formalin invalidates expensive tests, it might eventually be eliminated legislatively from diagnostic pathology. Finally, coagulant fixation is optimal for microwave histoprocessing where ethyl alcohol is followed by isopropanol.     

The use of mitochondrial and nuclear sequence data in assessing the taxonomic status of the endangered Uluguru Bush Shrike Malaconotus alius

The endangered Uluguru Bush Shrike Malaconotus alius is a large, black-headed bush shrike, strictly endemic to the Uluguru Mountains in Tanzania. It has recently been suggested that this species has been misplaced within the genus Malaconotus and might instead be related to Malagasy Vangidae. To assess its systematic affinities, we analysed 1518 bp of sequence data obtained from a nuclear intron (myoglobin intron-2) and a mitochondrial protein-coding gene (ND2) using parsimony, maximum likelihood and Bayesian inference. Both genes strongly support the traditional placement within the genus Malaconotus , suggesting that similarities between the Uluguru Bush Shrike and the Vangidae are due to convergence. These results caution that taxonomic changes should not be made without a proper character analysis (i.e. assignment of character homology).