Microscale investigation of anaerobic biogas production under various hydrodynamic conditions.

This work presents an investigation at microscale of various mechanisms affecting anaerobic reactions within the microdevices. In particular, the effect of different hydrodynamic conditions associated with the granular particles' size and density on the biogas production was studied in order to intensify the performance of the anaerobic reactor. The image analysis techniques offer an opportunity to observe and quantify the nucleation and growth of biogas bubble at microscale on a single granule. In addition, the flow conditions were perfectly controlled in the microdevice, and the liquid flow fields were measured by a microparticle image velocimetry (micro-PIV) system. The effect of real hydrodynamic conditions exerted directly on granules onto the maximum biogas production rate was described for the first time. Finally, the role of hydrodynamic conditions on the biogas production at microscale is discussed through a straightforward relationship between the shear rates exerted on the granule and the optimal biogas production rate. The investigation reveals that big granules could have satisfactory biogas production ability under relatively weak hydrodynamic conditions. Thus they would be priority selection for industrial reactors.

Cross-reactive antibody to swine influenza A(H3N2) subtype virus in children and adults before and after immunisation with 2010/11 trivalent inactivated influenza vaccine in Canada, August to November 2010.

In pre- and post-immunisation sera from children (17-120 months-old) and adults (20-59 years-old) immunised with 2010/11 trivalent inactivated influenza vaccine, we assessed age-related patterns of sero-susceptibility and vaccine-induced cross-reactive antibodies to a representative swine H3N2 (swH3N2) and a related ancestral human H3N2 (A/Sydney/5/1997) influenza virus. Few children but a greater proportion of adults showed pre-immunisation haemagglutination inhibition titres ≥40 to either virus. Titres increased with age among children but decreased in adults. Fewer than 20% showed a four-fold rise in antibody titres to either virus following immunisation. Further investigation is warranted to guide ongoing risk assessment and response to emerging swine H3N2 viruses.

In situ measurements of the physical characteristics of Titan's environment.

On the basis of previous ground-based and fly-by information, we knew that Titan's atmosphere was mainly nitrogen, with some methane, but its temperature and pressure profiles were poorly constrained because of uncertainties in the detailed composition. The extent of atmospheric electricity ('lightning') was also hitherto unknown. Here we report the temperature and density profiles, as determined by the Huygens Atmospheric Structure Instrument (HASI), from an altitude of 1,400 km down to the surface. In the upper part of the atmosphere, the temperature and density were both higher than expected. There is a lower ionospheric layer between 140 km and 40 km, with electrical conductivity peaking near 60 km. We may also have seen the signature of lightning. At the surface, the temperature was 93.65 +/- 0.25 K, and the pressure was 1,467 +/- 1 hPa.

A receptor in pituitary and hypothalamus that functions in growth hormone release.

Small synthetic molecules termed growth hormone secretagogues (GHSs) act on the pituitary gland and the hypothalamus to stimulate and amplify pulsatile growth hormone (GH) release. A heterotrimeric GTP-binding protein (G protein)-coupled receptor (GPC-R) of the pituitary and arcuate ventro-medial and infundibular hypothalamus of swine and humans was cloned and was shown to be the target of the GHSs. On the basis of its pharmacological and molecular characterization, this GPC-R defines a neuroendocrine pathway for the control of pulsatile GH release and supports the notion that the GHSs mimic an undiscovered hormone.

Human metapneumovirus infection in adults with community-acquired pneumonia and exacerbation of chronic obstructive pulmonary disease.

We tested nasopharyngeal aspirate specimens by real-time polymerase chain reaction assays and paired serum samples by enzyme-linked immunosorbent assays. Acute human metapneumovirus infections were identified in 6 (4.1%) of 145 adult patients who presented to the emergency department for pneumonia or acute exacerbation of chronic obstructive pulmonary disease during 2 winter/spring seasons in Quebec, Canada.

WT1 splicing alterations in Wilms' tumors.

Hereditary and sporadic forms of tumors are generally related to germ-line and somatic mutations of the same tumor suppressor gene. Unexpectedly, in Wilms' tumor, somatic mutations of the WT1 gene were found only occasionally in sporadic cases, although constitutional mutations of this gene are clearly associated with predisposition. It has been suggested that abnormal splicing may be another mode of somatic WT1 alteration. However, this idea was based on the analysis of a small series of tumors, precluding accurate evaluation of the frequency of such changes. To investigate WT1 changes at the somatic level in more detail, we analyzed the levels of the four isoform transcripts produced by alternative splicing events in a large series of 50 tumors, normal mature kidneys, and fetal kidneys. We characterized splicing alterations in 63% of sporadic Wilms' tumors. Moreover, taking into account the decreased and increased overall levels of WT1 mRNA, the percentage of sporadic tumors with changes in WT1 expression reached 90%. Whether and how these alterations of expression play a role in the tumorigenic process remain to be evaluated.

The 28S ribosomal RNA-encoding gene of Hymenoptera: inserted sequences in the retrotransposon-rich regions.

The genomes of two parasitoid wasps, Diadromus pulchellus and Eupelmus vuilleti, and the honey bee, Apis mellifera, contain few interspersed repeated sequences corresponding to transposons (Tn). This suggests that the genomic organisation of Hymenoptera could be due to the elimination of deleterious Tn in haploid males. We have used restriction-fragment length polymorphism analysis to show that nondeleterious Tn are present in the DNA (rDNA) encoding ribosomal RNA of twelve species of Hymenoptera. Sequence analysis of the 28S rDNA type-I and type-II insertion-rich regions of 80 species showed that this region is very highly conserved (95.8%). A consensus sequence and restriction map of the rDNA region were established. These sequence data were used to develop a strategy for detecting inserted elements in the rDNA fragments containing type-I or type-II insertion sites, and this strategy was used to screen twelve hymenopteran species and four non-Hymenoptera control species. The rDNA fragments from the Hymenoptera and control species contained inserted sequences in the area where type-I and type-II elements are inserted in the 28S rDNA retrotransposon-rich region of Diptera and Lepidoptera. The hymenopteran genomes therefore appear to contain repeated elements, the mobility and nature of which remain to be determined.

Human and other mammalian genomes contain transposons of the mariner family.

Internal fragments of the putative transposase gene of mariner-like elements (MLEs) were amplified from human, mouse, rat, chinese hamster, sheep and bovine genomic DNAs by polymerase chain reaction (PCR). The sequences identified in human, ovine and bovine genomes correspond to ancient degenerate transposons. Screening mammalian sequence libraries identified a truncated element in the human ABL gene and the sequence of its 5'-ITR was determined. This ITR sequences were used in PCR experiments with DNA from six mammalian species and detected full-sized and deleted MLEs. The presence of MLE in mammalian genomes demonstrates that they are ubiquitous mobile elements found from fungi to man. This observation strongly raises the possibility that MLE could constitute tools for the modification of eucaryotic genomes.

MEP (Mars Environment Package): toward a package for studying environmental conditions at the surface of Mars from future lander/rover missions.

In view to prepare Mars human exploration, it is necessary to promote and lead, at the international level, a highly interdisciplinary program, involving specialists of geochemistry, geophysics, atmospheric science, space weather, and biology. The goal of this program will be to elaborate concepts of individual instruments, then of integrated instrumental packages, able to collect exhaustive data sets of environmental parameters from future landers and rovers of Mars, and to favour the conditions of their implementation. Such a program is one of the most urgent need for preparing human exploration, in order to develop mitigation strategies aimed at ensuring the safety of human explorers, and minimizing risk for surface operations. A few main areas of investigation may be listed: particle and radiation environment, chemical composition of atmosphere, meteorology, chemical composition of dust, surface and subsurface material, water in the subsurface, physical properties of the soil, search for an hypothesized microbial activity, characterization of radio-electric properties of the Martian ionosphere. Scientists at the origin of the present paper, already involved at a high degree of responsibility in several Mars missions, and actively preparing in situ instrumentation for future landed platforms (Netlander--now cancelled, MSL-09), express their readiness to participate in both ESA/AURORA and NASA programs of Mars human exploration. They think that the formation of a Mars Environment working group at ESA, in the course of the AURORA definition phase, could act positively in favour of the program, by increasing its scientific cross-section and making it still more focused on human exploration.

Proteomic analysis of ovine muscle hypertrophy.

Two-dimensional electrophoresis was used to investigate the effects of a QTL for muscle hypertrophy on sarcoplasmic protein expression in ovine muscles. In the Belgian Texel breed, the QTL for muscle hypertrophy is localized in the myostatin-encoding gene. Based on microsatellite markers flanking the myostatin gene, we compared the hypertrophied genotype with the normal genotype. The average age of the sheep was 3 mo. Among the 4 muscles studied, in the hypertrophied genotype only the vastus medialis was normal, whereas the semimembranosus, tensor fasciae latae, and LM were hypertrophied. In the hypertrophied genotype, these muscles showed upregulation of enzymes involved in glycolytic metabolism together with oxidative metabolism in LM. Certain chaperone proteins, including glutathione S-transferase-Pi, heat shock protein-27, and heat shock cognate-70, were also more highly expressed, probably due to increased use of energetic pathways. Expression of the iron transport protein transferrin was increased. Alpha-1-antitrypsin was the only protein showing a similar pattern of expression (i.e., less expressed) in all 4 muscles of the hypertrophied genotype. It is suggested that transferrin and alpha-1-antitrypsin may interact to reinforce myogenic proliferative signaling.

Attentional requirements of walking in spinal cord injured patients compared to normal subjects.

STUDY DESIGN: Recent developments in the field of rehabilitation and the increase in the number of incomplete spinal cord injured subjects (SCI) emphasize the importance of studying the walking behavior of that population. OBJECTIVES: Attentional requirements were measured in spinal cord injured subjects during sitting, standing and walking and compared to a healthy group for the same tasks and walking at a similar speed. METHODS: Auditory stimuli and verbal responses were used to measure the attentional demands in the three experimental tasks. RESULTS: For both static tasks, SCI subjects were faster than the normal group. During walking at preferred speed, the normal group is significantly faster than the SCI subjects are. No difference was found between the two groups when the normal group walked at a similar speed. However, SCI subjects need to allocate significantly more attentional resource to walking than the normal. SCI patients also showed slower reaction times when the stimuli were presented during the single-support phase of walking. Kinematics analysis revealed that SCI subjects produced longer cycle duration than the normal group even when they walked at a match speed. Although variability in the cycle duration and the cycle length were comparable between the two groups, when the normal group walked at a slower speed, they were significantly more variable than the SCI subjects. CONCLUSION: Walking for SCI patients is cognitively challenging. Walking speed seems to be an important factor associated with attentional demands.

Interaction of serum proteins with lung endothelial glycocalyx: its effect on endothelial permeability.

To examine directly the interaction of circulating proteins (CP) with the glycocalyx of pulmonary endothelium and its effect on endothelial permeability, two types of experiments were carried out. In the first, rats were exchange transfused with graded amounts of FC-43 fluorocarbon emulsion (FCE) resulting in CP concentrations of 25, 10, and 4 mg/ml, respectively. In the second, rats were exchange transfused with FCE to remove 99.9% of CP. The rats were then exchange transfused with 1 ml FCE containing 60 mg/ml of rat serum protein and killed 3.5, 7.5, and 15 min after the administration of protein. In all animals the distribution of albumin and immunoglobulin G (IgG) was visualized by immunocytochemistry, and endothelial permeability to native ferritin was measured by morphometry. In the depletion experiments increased endothelial permeability to ferritin coincided with loss of adsorbed albumin and IgG from the glycocalyx. Conversely, the presence of administered serum proteins in the glycocalyx and in a few luminal vesicles was associated with an endothelial permeability to ferritin indistinguishable from that of controls. These observations suggest that the adsorption of CP to the endothelial glycocalyx renders the underlying endothelium less permeable to ferritin.

Expression of the three unlinked isocoding actin genes of Physarum polycephalum.

The actin gene family in Physarum polycephalum contains four unlinked loci: ardA, ardB, ardC, and ardD. The ardA locus is complex and probably contains two genes which we designated ardA2-7 and ardA2-17. cDNA clones corresponding to the ardB and ardC loci were isolated. Nucleic acid sequencing showed that these two cDNAs coded for the only abundant form of Physarum actin, which is 96% homologous to human gamma-cytoplasmic actin. The ardA2-17 gene also codes for this same actin protein (Nader et al., Gene 48, 133-144, 1986). The coding regions of ardB and ardC differ by 15 nucleotides. A comparison of the ardB and ardC sequences with ardA2-17 showed 73 and 77 nucleotide substitutions, respectively, in the coding regions. The noncoding regions of these three sequences were not homologous to each other or to the noncoding regions of actin genes from other organisms. Southern genomic hybridizations indicated that the ardA2-7 and ardD genes have weak sequence similarities to the three isocoding actin genes and thus form a different subclass of the family. Northern hybridizations showed that the ardB and ardC transcripts varied in abundance but were present in all the developmental stages. No ardA2-17 transcripts were seen. The relative abundance of the ardB and ardC transcripts was measured in amoebae and plasmodia by S1 nuclease protection and dot hybridization assays. A ratio of approximately 3:1 for ardC versus ardB was found for both stages. P. polycephalum is the first organism shown to contain three unlinked isocoding actin genes, of which at least two are expressed.

Are Drosophila melanogaster populations under a stable geographical differentiation due to the presence of P elements?

In order to simulate the outcome of the P-M status of Eurasian populations of Drosophila melanogaster, the evolution of experimental mixed-strains was monitored for up to 50 generations. The results were compared with the evolution in natura of European populations sampled in 1981-83 and 1986-87 over a similar period of time. Different combinations of P and M' strains, Q and M' strains, M' and M' strains and M and M' strains were set up at 25 degrees C and duplicated at 13 degrees C night-21 degrees C day. The possibility of a change towards a P type only appeared with the introduction of the strong P strain Harwich into Eurasian strains. Strains with strength similar to that of Harwich are not currently found in wild populations. With the introduction of weak P and Q strains of the strength presently observed in western Europe, experimental populations evolved slowly towards a Q state or a weak M' state. M'-M' mixed populations resulted in strong M' strains, as was the case for M-M' populations. In these cases. P sequences were not eliminated. In wild populations both genetic and molecular analyses showed no significant differences, over a five year period, for GD sterility potentials, for total P copy number or for distribution of the full-sized and KP elements. Changes in Eurasian populations are probably taking place at a very low rate and may even have stopped, leading to a quasi-stable differentiation over the continent. During the different steps of progressive invasion of P transposable elements, several deleted elements developed and natural selection may have acted on them. The possibility of the selection of different types of regulatory mechanisms according to the presence of different kinds of derivative elements, leading to a world-wide differentiation between P-Q and M' strains is discussed.

Heterochromatin condensation and evolution of unique satellite-DNA families in two parasitic wasp species: Diadromus pulchellus and Eupelmus vuilleti (Hymenoptera).

Large quantities of satellite DNA families (15%-25% of the genome) were found in the DNA of two species of parasitic wasps, Diadromus pulchellus and Eupelmus vuilleti. In both species the satellite DNA was found to consist wholly or largely of a single family unique to that species. Several clones of each family were obtained and sequenced. Palindromes in each consensus sequence suggest the formation in vivo of hairpin structures that may play a role in the mode of heterochromatin condensation in these insects. The ancestral repeating motifs were determined from the consensus sequences. Plausible scenarios are presented for the evolution of the two satellite DNAs. The occurrence of only one family of satellite DNAs in both species may indicate that, in male haploids, such families have shorter persistence times than necessary for the origins of new duplicated sequences.

[Residual nitrite and nitrate content in French cooked hams and shoulders]. / Les teneurs résiduaires en nitrites et nitrates des jambons et épaules cuits Français.

The test laboratory of the "Centre technique de la salaison, de la charcuterie et des conserves de viandes" has evaluated the nitrite and nitrate salts contents of 1 468 cooked hams and shoulders. 90,5 p. 100 of sample have a sodium nitrite content of less than 150 mg/kg. 81,5 p. 100 have a potassium nitrate content of less than 500 mg/kg. The measured contents show a wide scattering. The nitrite mean content is of 61 mg/kg with a standard deviation of 95. The nitrate mean content is of 292 mg/kg with a standard deviation of 382. There were no significant variations between the various categories of cooked hams and shoulders.

Mariner-like elements in hymenopteran species: insertion site and distribution.

Copies of mariner-like element (MLE) transposons in two species, the bumble bee, Bombus terrestris, and the ant, Myrmica ruginodis, were sequenced. The full-sized elements are 1250 bp long in both species and include 28-bp inverted terminal repeats. The five copies sequenced were approximately 75% similar to a mariner element (peach) of Drosophila mauritiana. The distribution of MLE in 27 hymenopteran species was studied by PCR and Southern blot hybridization; 93% of the species contained one or more of the four major forms of the element. They are inserted in their host genomes, in the middle of a degenerated 30-bp palindrome, which is itself located in an 85-bp conserved region with a purine-rich tail at one of its ends. The hymenopteran MLEs lie in a specific insertion site, suggesting that this region is conserved. It is thus possible that this region may be a selectively neutral insertion site, which would explain why these elements are widespread in hymenopteran genomes and are not eliminated by male haploidy.

Expression of the UNC-5 guidance receptor in the touch neurons of C. elegans steers their axons dorsally.

Growth cones in developing nervous systems encounter a sequence of extracellular cues during migration. In theory, a growth cone can navigate by selectively expressing or activating surface receptor(s) that recognize extracellular cues appropriate to each migratory phase. Using the simple Caenorhabditis elegans nervous system, we attempted to demonstrate that path selection by migrating growth cones can be predictably altered by ectopic expression of a single receptor. The unc-5 gene of C. elegans encodes a unique receptor of the immunoglobulin superfamily (UNC-5), required cell-autonomously to guide growth cone and mesodermal cell migrations in a dorsal direction on the epidermis. We report here that the UNC-5 receptor induces dorsally oriented axon trajectories when ectopically expressed in the touch receptor neurons which normally extend pioneer axons longitudinally or ventrally on the epidermis. These errant trajectories depend on unc-6, which encodes a putative epidermal path cue, just as normal dorsally oriented axon trajectories do (such as those of certain motor neurons), suggesting that UNC-5 acts to reorient the touch cell growth cones by using its normal guidance mechanisms. These results support previous evidence that UNC-5 and UNC-6 play instructive rules in guiding growth cone migrations on the epidermis in C. elegans, and indicate that pioneering growth cones, which normally migrate in different directions, may use equivalent intracellular signalling mechanisms for guidance.

The occurrence of the transposable element pogo in Drosophila melanogaster.

We examined the genomic occurrence of the transposable element pogo in over 120 strains of Drosophila melanogaster, from around the world and from different eras. All had multiple copies of a 2.1 kilobase (kb) pogo element, and multiple copies of several size classes between 1.0 and 1.8 kb. There were differences between strains in intensities or presences of deletion-derivative size classes, suggesting current or recent mobility in the species. We were unable to find any pogo-hybridization in eight other species in the genus, in three subgenera, or in the related Scaptomyza pallida. The pogo element may be a 'middle-aged' element in the genome of D. melanogaster, having entered the species since its divergence from its sibling species, but long before the P and hobo elements.