Influence of very low doses of ionizing radiation on Synechococcus lividus metabolism during the initial growth phase

Previous results from this laboratory have shown that very low chronic doses of gamma radiation can stimulate proliferation of the Cyanobacterium Synechococcus lividus. This modification of cell proliferation occurred during the first doubling. In this paper, we have compared the metabolism of cells cultivated in a normal environment or under chronic irradiation. Incubation of the cells in a new medium induced a high superoxide dismutase (EC 1.15.1.1, SOD) activity at the 18th hour and a degradation of phycocyanin, thus demonstrating that cells were submitted to a photooxidative stress. This increase in superoxide dismutase activity was followed by concomittant peaks of glutathione reductase (EC 1.6.4.2, GR) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49, G6P-DH) at the 24th hour. Irradiated cultures at a dose of 53.5 mGray/year show an earlier and higher peak of SOD, GR, and G6P-DH. In a second stage, cultures showed an earlier onset of photosynthesis under irradiation, as evidenced by an increase in pigment content and an enhancement of glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13, GAP-DH). These results show that the radiostimulation is related to the activation of enzymes protecting against peroxides that were induced under oxidative circumstances and to the activation of a glucose catabolism via the oxidative pentose phosphate pathway.Abbreviations mGy milli-Gray - SOD superoxide dismutase - G6P-DH glucose-6-phosphate dehydrogenase - GAP-DH glycer-aldehyde-3-phosphate dehydrogenase - GSSG oxidized glutathione     

Lack of Change in Basal Ganglia Neuropeptide Content Following Subacute 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine Treatment of the Common Marmoset

Treatment of common marmosets with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 1-4 mg/kg for up to 4 days) caused a profound parkinsonian state. Ten days from the start of MPTP treatment, all animals showed marked motor impairment, consisting of bradykinesia and akinesia, limb rigidity, postural abnormalities, loss of vocalisation and blink reflex, and, on occasions, postural tremor. Measurement of caudate-putamen monoamine content at this time showed a profound loss in 3,4-dihydroxyphenylethylamine, homovanillic acid, and 3,4-dihydroxyphenylacetic acid concentrations. Measurement of neuropeptide concentrations in the caudate-putamen, internal and external segments of the globus pallidus, nucleus accumbens, substantia nigra, frontal cortex, and hippocampus showed met-enkephalin, leu-enkephalin, and cholecystokinin (CCK-8) concentrations to be unaffected by MPTP treatment. There was a small decrease in the substance P content of frontal cortex, but otherwise the content of this neuropeptide was unaltered. Parkinsonism in the marmoset, induced by MPTP treatment 10 days earlier, does not alter neuropeptide concentrations in the manner observed in Parkinson's disease.     

Deep-sea squat lobster biogeography (Munidopsidae: Leiogalathea) unveils Tethyan vicariance and evolutionary patterns shared by shallow-water relatives

The ecology, abundance and diversity of galatheoid squat lobsters make them an ideal group to study deep-sea diversification processes. Here, we reconstructed the evolutionary and biogeographic history of Leiogalathea, a genus of circum-tropical deep-sea squat lobsters, in order to compare patterns and processes that have affected shallow-water and deep-sea squat lobster species. We first built a multilocus phylogeny and a calibrated species tree with a relaxed clock using StarBEAST2 to reconstruct evolutionary relationships and divergence times among Leiogalathea species. We used BioGeoBEARS and a DEC model, implemented in RevBayes, to reconstruct ancestral distribution ranges and the biogeographic history of the genus. Our results showed that Leiogalathea is monophyletic and comprises four main lineages; morphological homogeneity is common within and between clades, except in one; the reconstructed ancestral range of the genus is in the Atlantic and Indian oceans (Tethys). They also revealed the divergence of the Atlantic species around 25 million years ago (Ma), intense cladogenesis 15–25 Ma and low levels of speciation over the last 5 million years (Myr). The four Leiogalathea lineages showed similar patterns of speciation: allopatric speciation followed by range expansion and subsequent stasis. Leiogalathea started diversifying during the Oligocene, likely in the Tethyan. The Atlantic lineage then split from its Indo-Pacific sister group due to vicariance driven by closure of the Tethys Seaway. The Atlantic lineage is less speciose compared with the Indo-Pacific lineages, with the Tropical Southwestern Pacific being the current centre of diversity. Leiogalathea diversification coincided with cladogenetic peaks in shallow-water genera, indicating that historical biogeographic events similarly shaped the diversification and distribution of both deep-sea and shallow-water squat lobsters.     

The invasive Leptoglossus seed bug,a threat for commercial seed crops,but for conifer diversity?

Among the recent introductions of alien insects in Europe, the polyphagous western conifer seed bug, Leptoglossus occidentalis Heidemann (Heteroptera; Coreidae) can seriously be regarded as a major threat for all the European conifer forests. In the current study combining laboratory and field experimentations, we characterized first bug damage by developing specific damage categories on seeds of different conifer species by the use of X-ray. Secondly, we investigated the impact of the invasive bug on key conifer species used for afforestation in Western and Central Europe. For this purpose, we performed germination tests on predated seeds which revealed that even light damage (consumption of <1/3 of the whole seed content) strongly reduced the germination capability of the seed. We also compared the impact of feeding on the proportion of filled seeds. Second year cones of Pinus sylvestris and Pinus nigra have been enclosed and offered to different life stages (nymphs and adults) and the results showed a significant reduction of filled seeds whatever the life stage. In field, we annually surveyed the bug seed damage for six different conifer species planted in southwestern French seed orchards. Taking into account the economic value of improved seeds in seed orchards, economic impact of bug damage was important although never exceeded 25 %. Two natural or semi-natural alpine pine stands were also surveyed and appeared to be highly affected by the bug (up to 70 % of damaged seeds). Therefore, bug damage could also be considered as a serious threat for seed production in natural stands.     

Study protocol of the YOU CALL - WE CALL TRIAL: impact of a multimodal support intervention after a "mild" stroke

Background

More than 60% of new strokes each year are "mild" in severity and this proportion is expected to rise in the years to come. Within our current health care system those with "mild" stroke are typically discharged home within days, without further referral to health or rehabilitation services other than advice to see their family physician. Those with mild stroke often have limited access to support from health professionals with stroke-specific knowledge who would typically provide critical information on topics such as secondary stroke prevention, community reintegration, medication counselling and problem solving with regard to specific concerns that arise. Isolation and lack of knowledge may lead to a worsening of health problems including stroke recurrence and unnecessary and costly health care utilization. The purpose of this study is to assess the effectiveness, for individuals who experience a first "mild" stroke, of a sustainable, low cost, multimodal support intervention (comprising information, education and telephone support) - "WE CALL" compared to a passive intervention (providing the name and phone number of a resource person available if they feel the need to) - "YOU CALL", on two primary outcomes: unplanned-use of health services for negative events and quality of life.

Method/Design

We will recruit 384 adults who meet inclusion criteria for a first mild stroke across six Canadian sites. Baseline measures will be taken within the first month after stroke onset. Participants will be stratified according to comorbidity level and randomised to one of two groups: YOU CALL or WE CALL. Both interventions will be offered over a six months period. Primary outcomes include unplanned use of heath services for negative event (frequency calendar) and quality of life (EQ-5D and Quality of Life Index). Secondary outcomes include participation level (LIFE-H), depression (Beck Depression Inventory II) and use of health services for health promotion or prevention (frequency calendar). Blind assessors will gather data at mid-intervention, end of intervention and one year follow up.

Discussion

If effective, this multimodal intervention could be delivered in both urban and rural environments. For example, existing infrastructure such as regional stroke centers and existing secondary stroke prevention clinics, make this intervention, if effective, deliverable and sustainable.

Trial Registration

ISRCTN95662526     

Loss of STOP Protein Impairs Peripheral Olfactory Neurogenesis

Background

STOP (Stable Tubulin-Only Polypeptide) null mice show behavioral deficits, impaired synaptic plasticity, decrease in synaptic vesicular pools and disturbances in dopaminergic transmission, and are considered a neurodevelopmental model of schizophrenia. Olfactory neurons highly express STOP protein and are continually generated throughout life. Experimentally-induced loss of olfactory neurons leads to epithelial regeneration within two months, providing a useful model to evaluate the role played by STOP protein in adult olfactory neurogenesis.

Methodology/Principal Findings

Immunocytochemistry and electron microscopy were used to study the structure of the glomerulus in the main olfactory bulb and neurogenesis in the neurosensorial epithelia. In STOP null mice, olfactory neurons showed presynaptic swellings with tubulovesicular profiles and autophagic-like structures. In olfactory and vomeronasal epithelia, there was an increase in neurons turnover, as shown by the increase in number of proliferating, apoptotic and immature cells with no changes in the number of mature neurons. Similar alterations in peripheral olfactory neurogenesis have been previously described in schizophrenia patients. In STOP null mice, regeneration of the olfactory epithelium did not modify these anomalies; moreover, regeneration resulted in abnormal organisation of olfactory terminals within the olfactory glomeruli in STOP null mice.

Conclusions/Significance

In conclusion, STOP protein seems to be involved in the establishment of synapses in the olfactory glomerulus. Our results indicate that the olfactory system of STOP null mice is a well-suited experimental model (1) for the study of the mechanism of action of STOP protein in synaptic function/plasticity and (2) for pathophysiological studies of the mechanisms of altered neuronal connections in schizophrenia.     

Hidden diversity and cryptic speciation refute cosmopolitan distribution in Caprella penantis (Crustacea: Amphipoda: Caprellidae)

Caprella penantis is considered a cosmopolitan species and one of the most challenging caprellids in taxonomic terms because of its remarkable intraspecific morphological variation. This study examined DNA sequences from mitochondrial (COI) and nuclear (18S) markers together with morphological data from 25 localities of C. penantis, and closely related species Caprella dilatata and Caprella andreae, all traditionally considered part of the old ‘acutifrons’ complex. The large genetic divergence and reciprocally allopatric distributions point to the existence of a species complex of at least four species, of which one is reported as a cryptic species. This study provides the first evidence of cryptic speciation in the family Caprellidae, and questions the validity of some traditional morphological characters used to delimit species in the genus Caprella. Our results are consistent with the idea that main factors were probably isolation by distance and ecological traits, promoting diversification in C. penantis. The strong genetic structure reported for this species in the Iberian Peninsula and Moroccan coasts also suggests restriction to dispersal as well as the presence of refugial areas. These results highlight the utility of the COI and 18S genes in combination with morphological characters for shedding light on systematic questions in caprellids, and patterns of genetic connectivity.     

Une lame de faucille sous la stèle gravée Chalcolithique dite du « Chef de tribu », Vallée des Merveilles, région du Mont Bego, Tende, Alpes-Maritimes

The carved stele known as the “head of the tribe”, attributed to the Chalcolithic, erected at an altitude of 2290 m in the chaos of blocks in the Merveilles torrent in the Mont Bego region at Tende, was removed from its original standing place. Earth extracted from under the stele and sieved yielded a sickle blade in very fine and homogeneous Bedoulian pale biege translucid flint, pressure flaked on a heated core. The blade bears a light polish caused by cereal harvesting. This sickle blade is similar to those widely used in the southern Chassey culture (4300 to 3000 years before our era) but also sometimes in the Campaniform culture, during the ancient and middle Bronze age, like in Murée cave, in the Verdon gorges. The location of the sickle blade at the foot of the carved stele, known as the “head of the tribe”, is not just coincidental. It is highly probable that the blade was intentionally placed beside this rock. It is seemingly during a ritual ceremony that this sickle blade, probably still inserted in a wooden handle, was intentionally placed, in a propitious gesture or as an offering, beside the stele known as the “head of the tribe”.     

Respiratory muscle strength training with nonrespiratory maneuvers.

The diaphragm and abdominal muscles can be recruited during nonrespiratory maneuvers. With these maneuvers, transdiaphragmatic pressures are elevated to levels that could potentially provide a strength-training stimulus. To determine whether repeated forceful nonrespiratory maneuvers strengthen the diaphragm, four healthy subjects performed sit-ups and biceps curls 3-4 days/wk for 16 wk and four subjects served as controls. The maximal transdiaphragmatic pressure was measured at baseline and after 16 wk of training. Maximum static inspiratory and expiratory mouth pressures and diaphragm thickness derived from ultrasound were measured at baseline and 8 and 16 wk. After training, there were significant increases in diaphragm thickness [2.5 +/- 0.1 to 3.2 +/- 0.1 mm (mean +/- SD) (P < 0.001)], maximal transdiaphragmatic pressure [198 +/- 21 to 256 +/- 23 cmH2O (P < 0.02)], maximum static inspiratory pressure [134 +/- 22 to 171 +/- 16 cmH2O (P < 0.002)], maximum static expiratory pressure [195 +/- 20 to 267 +/- 40 cmH2O (P < 0.002)], and maximum gastric pressure [161 +/- 5 to 212 +/- 40 cmH2O (P < 0.03)]. These parameters were unchanged in the control group. We conclude that nonrespiratory maneuvers can strengthen the inspiratory and expiratory muscles in healthy individuals. Because diaphragm thickness increased with training, the increase in maximal pressures is unlikely due to a learning effect.     

Males of the predatory mirid bug Macrolophus caliginosus exploit plant volatiles induced by conspecifics as a sexual synomone

The olfactory responses of male and female Macrolophus caliginosus Wagner (Heteroptera: Miridae) adults towards volatiles from green bean plants previously exposed to feeding by conspecifics and to direct odours from conspecifics were tested in a Y-tube olfactometer. Female M. caliginosus did not respond to volatiles from plants exposed to mirid feeding or to odours emitted directly by adult mirids. In contrast, male mirid bugs were attracted both to volatiles from plants previously exposed to feeding by conspecific females and to odours emitted by conspecifics only with a marginally significant preference for the former. The gas chromatography-mass spectrometry analysis showed that mirid feeding induced the release of 11 additional compounds as compared to the volatiles emitted from clean plants. Three of these substances (5-ethyl-2(5H)-furanone, Z-3-hexenyl tiglate, and E,E-α-farnesene) were released only after feeding by females. Furthermore, 21 compounds were identified in volatiles emitted directly by mirids, 12 of which were unique to the mirids (i.e., not present in clean plants or plants previously exposed to mirid feeding). The results suggest that female-specific herbivore-induced plant volatiles play a role as mate-finding cues by the male mirids. The ecological implications of the findings are discussed, and the term ‘sexual synomone’ is introduced.