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.

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.

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.

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.

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.

The wild-type conformation of the Mos-1 inverted terminal repeats is suboptimal for transposition in bacteria.

The two inverted terminal repeats (ITRs) flanking the Mos-1 mariner element differ in sequence at four positions. Gel retardation experiments indicated that each of these differences has a significant impact on the quality of the interaction between the ITR and the Mos-1 transposase. We showed that the transposase binds to the 3' ITR better than to the 5' ITR. The results of transposition assays performed in Escherichia coli indicated that these differences have an influence on the rate of transposition and the stability of the transposition products. Finally, we find that the wild-type configuration of the Mos-1 element, with one 5' ITR and one 3' ITR, is less efficient for transposition in bacteria than that of an element having two 3' ITRs.

The ITR binding domain of the Mariner Mos-1 transposase.

Mariner-like elements are widespread eukaryotic transposons, but Mos-1 is the only natural element that is known to be active. Little is known about the biochemistry of mariner transposition. The first step in the process is the binding of the transposase to the 5' and 3' inverted terminal repeats (ITRs) of the element. Using the 3' ITR of the element, we have determined the binding properties of a recombinant Mos-1 transposase produced in bacteria, and we have used deletion derivatives to localize the minimal ITR binding domain between amino acids 1 and 141. Its features and structure indicate that it differs from the ITR binding domain of the transposase encoded by Tc1-related elements.

Features of the mammal mar1 transposons in the human, sheep, cow, and mouse genomes and implications for their evolution.

Mariner-like elements (MLE) belong to the Tc1/ mariner superfamily of class II transposons. We have analyzed the mariner related to the cecropia subfamily, and called mammal mar1, in four mammalian genomes, Bos taurus (Bovidae), Homo sapiens (Primata), Mus musculus (Rodentia), and Ovis aries (Ovidae). Three kinds of MLE sequences were found in all these species: full-length 1.3-kbp elements, shorter elements 80 bp-1.2 kbp, and single inverted terminal repeats (ITRs). All the 1.3-kbp genomic copies sequenced had an open reading frame encoding a transposase interrupted by stop codons or frame shifts. Phylogenetic analysis of the full-length elements suggested at least two distinct populations of mammal mar1 elements in each species. This was confirmed by using a statistical method that allows defining populations. Finally, the evolutionary origin of the mammal mar1 elements and the paradoxes are discussed.

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.

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.

MEC-12, an alpha-tubulin required for touch sensitivity in C. elegans.

mec-12 is one of a dozen genes required for touch receptor neuron function in Caenorhabditis elegans. Some mec-12 mutants (mechanosensory-defective) lack the large-diameter microtubules that are characteristic of these neurons (15 protofilaments, as opposed to 11). Mutants of mec-7, a alpha-tubulin encoding gene, have a similar phenotype. We have identified the nature of mec-12 by germline transformation rescue and characterization of a point mutation. Sequence analysis of the mec-12 encoded product (MEC-12) indicates that it corresponds to a novel C. elegans alpha-tubulin. MEC-12 is the only identified C. elegans alpha-tubulin that contains a lysine at position 40, a known site of post-translational acetylation. Some mec-12 mutations eliminate microtubule acetylation as assayed immunocyto-chemically; phenotypic rescue using a MEC-12 variant lacking the lysine-40 showed that acetylation is not required for MEC-12 activity. Although functionally needed only in the touch neurons, mec-12 is expressed in several other neuron types. These results support the notion that tubulin isotype diversity contributes to the formation of distinct classes of microtubules; 15-protofilament microtubule assembly requires MEC-12 alpha-tubulin and MEC-7 beta-tubulin, which are both highly expressed in the touch receptor neurons. MEC-12 is the first reported alpha-tubulin isotype that appears to be required in a single class of neuronal microtubules.

Evolutionary relationship of the ligand-gated ion channels and the avermectin-sensitive, glutamate-gated chloride channels.

Two cDNAs, GluClalpha and GluClbeta, encoding glutamate-gated chloride channel subunits that represent targets of the avermectin class of antiparasitic compounds, have recently been cloned from Caenorhabditis elegans (Cully et al., Nature, 371, 707-711, 1994). Expression studies in Xenopus oocytes showed that GluClalpha and GluClbeta have pharmacological profiles distinct from the glutamate-gated cation channels as well as the gamma-aminobutyric acid (GABA)- and glycine-gated chloride channels. Establishing the evolutionary relationship of related proteins can clarify properties and lead to predictions about their structure and function. We have cloned and determined the nucleotide sequence of the GluClalpha and GluClbeta genes. In an attempt to understand the evolutionary relationship of these channels with the members of the ligand-gated ion channel superfamily, we have performed gene structure comparisons and phylogenetic analyses of their nucleotide and predicted amino acid sequences. Gene structure comparisons reveal the presence of several intron positions that are not found in the ligand-gated ion channel superfamily, outlining their distinct evolutionary position. Phylogenetic analyses indicate that GluClalpha and GluClbeta form a monophyletic subbranch in the ligand-gated ion channel superfamily and are related to vertebrate glycine channels/receptors. Glutamate-gated chloride channels, with electrophysiological properties similar to GluClalpha and GluClbeta, have been described in insects and crustaceans, suggesting that the glutamate-gated chloride channel family may be conserved in other invertebrate species. The gene structure and phylogenetic analyses in combination with the distinct pharmacological properties demonstrate that GluClalpha and GluClbeta belong to a discrete ligand-gated ion channel family that may represent genes orthologous to the vertebrate glycine channels.

Particle and genomic characteristics of a new member of the Ascoviridae: Diadromus pulchellus ascovirus.

A new member of the family Ascoviridae, Diadromus pulchellus ascovirus (DpAV), has been found in the lepidopteran nymphs of Acrolepiopsis assectella parasitized by the hymenopteran wasp Diadromus pulchellus. Virions have the standard features of the ascovirus group; each particle is about 220 nm long and 150 nm wide. They are multilayered, with two clear 7-nm-thick outer layers and one 15-nm-thick inner layer surrounding an electron-dense core (155 x 110 nm). However, the flattened rice-grain shape and fragility of the DpAV particles are unlike that of known ascoviruses infecting Noctuidae species. They form large vesicles containing virions in infected cells. The DpAV genome is about 116 kb long and has a circular and relaxed structure. It contains 6-8 repeated and interspersed sequences of 494 bp. The structural and genomic features of DpAV suggest that this virus belongs to an ascovirus sub-family different from that containing the ascoviruses previously found to infect species of Noctuidae (Federici et al., 1991).

Biological and molecular features of the relationships between Diadromus pulchellus ascovirus, a parasitoid hymenopteran wasp (Diadromus pulchellus) and its lepidopteran host, Acrolepiopsis assectella.

The Diadromus pulchellus ascovirus (DpAV) has been isolated from laboratory strains of Diadromus pulchellus and in natural wild populations collected from the Antibes locality (southern France). The DpAV genome was found in the cells of the head, thorax and abdomen of this hymenopteran wasp. DpAV virions are present in the female genitalia and are transmitted to the nymphal lepidopteran host, Acrolepiopsis assectella, at each oviposition of the female wasp. The presence of the DpAV genome in all Diadromus somatic cells suggests that it is inherited by vertical transmission. DpAV is amplified in the host tissues during the larval development of D. pulchellus in A. assectella. Cell lysis due to amplification of the virus does not prevent the development of the hymenopteran larva. Virus amplification appears to be slower in nymphs parasitized by D. pulchellus than in nymphs artificially infected with DpAV alone. Lysis of the nymphal cells due to viral replication seems to be synchronous with egg hatching and the development of the hymenopteran larva. The features of DpAV and its relationship with the parasitoid wasp D. pulchellus during its development are compared to those of the ichnoviruses.

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.

Effect of an unknown toxin isolated from Dinophysis sp.-contaminated French mussels, on the electrical and mechanical activity of frog heart.

The effects of an unknown toxin, isolated along with okadaic acid from the hepatopancreas of French mussels contaminated by Dinophysis sp., producing ataxia, neurologic symptoms, bradycardia, arrhythmias, electrocardiographic changes, and cardiac arrest, have been studied in terms of the electrical and mechanical activity of frog atrial heart muscle. The toxin, in a dose-dependent manner, decreased the amplitude of the stimulated peak tension of isolated fibers. The toxin (1-36 micrograms/ml) did not modify the membrane resting potential but decreased the amplitude of the plateau and shortened the duration of the action potential. The toxin inhibited the Cd-sensitive L-type Ca current and increased a 4-aminopyridine-sensitive outward current in voltage-clamped cardiac myocytes. The data show that the cardiac effect of the toxin is markedly different from that of okadaic acid.

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.

The genome segments of DpRV, a commensal reovirus of the wasp Diadromus pulchellus (Hymenoptera).

The complete nucleotide sequences of the five double-stranded RNA genome segments of the Diadromus pulchellus reovirus (DpRV) have been determined. They consist of 985, 1240, 1318, 1652, and 4230 bp. Each segment contains at least one putative open reading frame encoding 33-, 40-, 45-, 49-, and 148-kDa proteins, respectively. The proteins have no significant similarities with sequences in data banks. Analysis of these segments and of two other previously published segments revealed the presence of degenerate consensus inverted repeats at both ends (5'-rCAAUUUUnnACU...AGUAAAAAAAUnrG-3'). The biological, structural, and genomic features of DpRV suggest that this virus is related to members of the Orthoreovirus genus.