Estimation by PLFA of Microbial Community Structure Associated with the Rhizosphere of Lygeum spartum and Piptatherum miliaceum Growing in Semiarid Mine Tailings

The objective of this study was to compare the microbial community composition and biomass associated with the rhizosphere of a perennial gramineous species (Lygeum spartum L.) with that of an annual (Piptatherum miliaceum L.), both growing in semiarid mine tailings. We also established their relationship with the contents of potentially toxic metals as well as with indicators of soil quality. The total phospholipid fatty acid (PLFA) amount was significantly higher in the rhizosphere soil of the annual species than in the rhizosphere soil of the perennial species. The fungal/bacterial PLFA ratio was significantly greater in the perennial species compared to the annual species. The fatty acid 16:1ω5c, the fungal/bacterial PLFA ratio and monounsaturated/saturated PLFA ratio were correlated negatively with the soluble contents of toxic metals. The cyc/prec (cy17:0 + cy19:0/16:1ω7 + 18:1ω7) ratio was correlated positively with the soluble contents of Pb, Zn, Al, Ni, Cd, and Cu. The results of the PLFA analysis for profiling microbial communities and their stress status of both the plant species indicate that perennial and annual gramineous species appear equally suitable for use in programmes of revegetation of semiarid mine tailings.     

A Predominant Multidrug-Resistant Salmonella enterica Serovar Saintpaul Clonal Line in German Turkey and Related Food Products

Recently, Salmonella enterica subsp. enterica serovar Saintpaul has increasingly been observed in several countries, including Germany. However, the pathogenic potential and epidemiology of this serovar are not very well known. This study describes biological attributes of S. Saintpaul isolates obtained from turkeys in Germany based on characterization of their pheno- and genotypic properties. Fifty-five S. Saintpaul isolates from German turkeys and turkey-derived food products isolated from 2000 to 2007 were analyzed by using antimicrobial agent, organic solvent, and disinfectant susceptibility tests, isoelectric focusing, detection of resistance determinants, plasmid profiling, pulsed-field gel electrophoresis (PFGE), and hybridization experiments. These isolates were compared to an outgroup consisting of 24 S. Saintpaul isolates obtained from humans and chickens in Germany and from poultry and poultry products (including turkeys) in Netherlands. A common core resistance pattern was detected for 27 German turkey and turkey product isolates. This pattern included resistance (full or intermediate) to ampicillin, amoxicillin-clavulanic acid, gentamicin, kanamycin, nalidixic acid, streptomycin, spectinomycin, and sulfamethoxazole and intermediate resistance or decreased susceptibility to ciprofloxacin (MIC, 2 or 1 μg/ml, respectively) and several third-generation cephalosporins (including ceftiofur and cefoxitin [MIC, 4 to 2 and 16 to 2 μg/ml, respectively]). These isolates had the same core resistance genotype, with bla_TEM-1, aadB, aadA2, sul1, a Ser83→Glu83 mutation in the gyrA gene, and a chromosomal class 1 integron carrying the aadB-aadA2 gene cassette. Their XbaI, BlnI, and combined XbaI-BlnI PFGE patterns revealed levels of genetic similarity of 93, 75, and 90%, respectively. This study revealed that a multiresistant S. Saintpaul clonal line is widespread in turkeys and turkey products in Germany and was also detected among German human fecal and Dutch poultry isolates.Over the last few decades, the emergence and spread of antimicrobial agent-resistant zoonotic bacteria has become a serious public health concern (2, 23). The widespread use of antimicrobial agents for disease control, including at the farm level, has increased selection of antimicrobial agent-resistant Salmonella isolates (1, 23, 44). Food animals are considered an important reservoir for resistant bacteria. These animals and food products derived from them are traded worldwide, which contributes to the global spread of zoonotic agents and antimicrobial resistance. In the last few years, several monitoring activities were initiated in order to generate baseline data on antimicrobial resistance in bacteria isolated from livestock and food derived from animals that could be used in future assessments of the risk of antimicrobial resistance (10).According to European Union (EU) Zoonoses Regulation (EC) no. 2160/2003 on the control of Salmonella and other specified food-borne zoonotic agents, a European Community target for reducing the prevalence of Salmonella in turkey flocks had to be established. Consequently, EU Commission decision 2006/662/EC was released, and a baseline survey of the prevalence of Salmonella in turkey flocks was carried out in all European countries, including Germany, over a 1-year period starting on 1 October 2006 (http://www.efsa.europa.eu/EFSA/efsa_locale-1178620753812_1178706574172.htm). The main objective of this study was to estimate the prevalence of Salmonella in commercial flocks of turkeys. The data showed that at the EU level Salmonella enterica serovar Bredeney was the serovar reported most frequently for fattening turkey flocks and occurred in 17.2% of the samples from Salmonella-positive flocks (1,084 of 3,702 flocks were positive), followed by S. enterica serovar Hadar, S. enterica serovar Derby, and then S. enterica serovar Saintpaul (14.0%, 11.3%, and 10.4% of the samples from positive flocks, respectively). In this study, S. Saintpaul was detected in fattening turkeys in 12 countries, reflecting the wide spread of this serovar. Recently, S. Saintpaul has been increasingly observed in several countries, including Germany. According to Enter-Net reports (data on Salmonella human isolates identified by European national reference centers), for the last quarter of the year 2006 S. Saintpaul was the fourth most common serovar (1.6%) and, in contrast to the data for previous years, was one of the most frequent causes of human salmonellosis in Europe. After this, its prevalence was 1.2% and 0.6% in the first quarters of 2007 and 2008, respectively, among the Salmonella serotypes implicated in human disease (http://ecdc.europa.eu/en/publications/Pages/Surveillance_Reports.aspx). During the period from 2001 to 2009 in Germany, 463 cases of human salmonellosis related to S. Saintpaul (0.09% of all cases; the maximum prevalence was 0.15% in 2008, the prevalence was 0.1% in 2002, 2005, 2006, and 2009 and 0.06% in 2004, and the minimum prevalence was 0.05% in 2007) were reported to the Robert Koch Institute (Berlin, Germany) (www3.rki.de/SurvStat). In Germany, S. Saintpaul attracted public attention particularly in 1993, when it caused a nationwide food-borne outbreak (27). This serotype has often been related to outbreaks in other countries, and in 2008 it was implicated in a large multistate human outbreak associated with various vegetables in the United States (4).Previous studies showed that isolates of S. Saintpaul are often multidrug resistant (33, 35), but little is known about the mechanisms underlying antimicrobial resistance or about the pathogenic potential and epidemiology of isolates belonging to this serotype. The goals of this study were to obtain information about the resistance characteristics of isolates collected between 2000 and 2007 in Germany and to assess possible clonal relationships. The isolates used originated from turkey feces collected during the German Salmonella baseline study (in 2006 and 2007) or from diagnostic samples, including samples of turkey feces and turkey-related food products. These isolates were compared with German strains isolated from humans and chickens and with poultry strains isolated in Netherlands.     

Effects of NaCl on surface properties,chlorophyll fluorescence and light remission,and cellular compounds of <Emphasis Type="Italic">Grewia tenax</Emphasis> (Forssk.) Fiori and <Emphasis Type="Italic">Tamarindus indica</Emphasis> L. leaves

Seedlings of the salt-tolerant plant grewia [Grewia tenax (Forssk.) Fiori] and the moderately salt-tolerant tamarind (Tamarindus indica L.) were grown under controlled conditions and treated daily with NaCl solutions to investigate mechanisms of tolerance to salinity. Leaf micromorphology, cuticular wax load, chlorophyll fluorescence and light remission, as well as antioxidative potential were evaluated. As confirmed by energy-dispersive X-ray microanalysis in both species, absorption of sodium and chlorine increased with rising NaCl concentration in the treatment solution. In parallel, accumulation of calcium in grewia leaves was strongly reduced, leading to less crystals of calcium oxalate in leaf tissue. In grewia the cuticular wax load, chlorophyll content, and electron transport rate (ETR) were significantly reduced by comparatively low NaCl concentrations. In tamarind, in contrast, wax load and ETR were not significantly affected, while the decrease of chlorophyll content was less pronounced. Measurements of the antioxidative capacity and the imbalance between values of lipophilic and hydrophilic extracts at different NaCl concentrations confirmed that grewia is more salt tolerant than tamarind. This higher tolerance degree seemed to be associated with grewias’ more efficient scavenging of free radicals and the regulation of the antioxidative potential in lipophilic and hydrophilic extracts.     

Beneficial Effect of Verminephrobacter Nephridial Symbionts on the Fitness of the Earthworm Aporrectodea tuberculata

Almost all lumbricid earthworms (Oligochaeta: Lumbricidae) harbor species-specific Verminephrobacter (Betaproteobacteria) symbionts in their nephridia (excretory organs). The function of the symbiosis, and whether the symbionts have a beneficial effect on their earthworm host, is unknown; however, the symbionts have been hypothesized to enhance nitrogen retention in earthworms. The effect of Verminephrobacter on the life history traits of the earthworm Aporrectodea tuberculata (Eisen) was investigated by comparing the growth, development, and fecundity of worms with and without symbionts given high (cow dung)- and low (straw)-nutrient diets. There were no differences in worm growth or the number of cocoons produced by symbiotic and aposymbiotic worms. Worms with Verminephrobacter symbionts reached sexual maturity earlier and had higher cocoon hatching success than worms cured of their symbionts when grown on the low-nutrient diet. Thus, Verminephrobacter nephridial symbionts do have a beneficial effect on their earthworm host. Cocoons with and without symbionts did not significantly differ in total organic carbon, total nitrogen, or total hydrolyzable amino acid content, which strongly questions the hypothesized role of the symbionts in nitrogen recycling for the host.Symbiosis has long been recognized as a source of evolutionary innovation (24), and the acquisition of symbionts can enable animal hosts to exploit previously inaccessible niches (3). The phylum Annelida is no exception to this; chemosynthetic symbionts in marine annelids (e.g., the giant tubeworm Riftia sp. and other gutless marine oligochaetes [9]) gain energy from the oxidation of reduced sulfur compounds and fix CO₂ and supply their animal host with fixed carbon. A more obscure partnership is known from the bone-eating annelid Osedax sp., where endosymbionts help degrade the bones of whale carcasses, the only known habitat of the worms (33). The medicinal leech Hirudo sp., like other blood-feeding animals (3, 7), has symbionts that are thought to produce essential vitamins missing from a blood meal (13). In addition, leeches have a number of symbionts of unknown function in their nephridia (excretory organs) (18). Earthworms (Oligochaeta: Lumbricidae) have also long been known to harbor symbiotic bacteria in their nephridia (19, 36). The function of this symbiosis, however, is still not known, but the stability of the symbiosis over evolutionary time (23) suggests that the symbionts benefit the host.The earthworm symbionts reside in the nephridia and have therefore been proposed to be involved in internal recycling of nitrogen in the host (29). The earthworm nephridia play an important role in both nitrogenous waste excretion and osmoregulation (20). The nephridia are found in pairs in each segment of the worm and consist of a coiled tube leading from the coelom to the exterior (Fig. ​(Fig.1).1). The tube forms three loops, and the symbiotic bacteria are situated in the ampulla in the second loop, where they form a dense population lining the lumen wall (19, 36).Open in a separate windowFIG. 1.The nephridia are found as paired organs in each segment of the worm. The nephridostome (the inlet to the nephridia) protrudes into the previous segment. The nephridial tube forms three loops and finally empties out through the body wall via the nephridopore. The symbionts (black) reside in the ampulla in the second loop. (Modified from reference 23 with permission.)The symbionts form the monophyletic genus Verminephrobacter (Betaproteobacteria) (30, 36); they are species specific and present in almost all lumbricid earthworms (23). The Verminephrobacter symbionts are transmitted vertically via the cocoon, where they are deposited along with eggs and sperm (5). During embryogenesis, the symbionts migrate into the developing nephridia, and after the worm hatches, the symbionts can no longer infect (5, 6). By taking advantage of the vertical transmission mode, it has been possible to establish symbiont-free earthworm cultures in the laboratory through controlled antibiotic treatment of newly deposited cocoons (5; this study). Separation of the symbiotic partners allows studies of the effect of the symbionts on their earthworm hosts.Pandazis (29) hypothesized that the symbionts enhance earthworm nitrogen retention by excreting proteolytic enzymes that will degrade peptides and proteins lost in urine; this would allow the earthworm to reabsorb the resulting amino acids. As a consequence, earthworms cured of their symbionts should have a lower fitness level than control worms when grown under nitrogen-limiting conditions. To test this hypothesis, growth, development, fecundity, and cocoon hatching success were compared for symbiotic and aposymbiotic earthworms of the species Aporrectodea tuberculata (Eisen) under high and low nutrient availability conditions.     

Cranioectodermal Dysplasia, Sensenbrenner Syndrome, Is a Ciliopathy Caused by Mutations in the IFT122 Gene

Cranioectodermal dysplasia (CED) is a disorder characterized by craniofacial, skeletal, and ectodermal abnormalities. Most cases reported to date are sporadic, but a few familial cases support an autosomal-recessive inheritance pattern. Aiming at the elucidation of the genetic basis of CED, we collected 13 patients with CED symptoms from 12 independent families. In one family with consanguineous parents two siblings were affected, permitting linkage analysis and homozygosity mapping. This revealed a single region of homozygosity with a significant LOD score (3.57) on chromosome 3q21-3q24. By sequencing candidate genes from this interval we found a homozygous missense mutation in the IFT122 (WDR10) gene that cosegregated with the disease. Examination of IFT122 in our patient cohort revealed one additional homozygous missense change in the patient from a second consanguineous family. In addition, we found compound heterozygosity for a donor splice-site change and a missense change in one sporadic patient. All mutations were absent in 340 control chromosomes. Because IFT122 plays an important role in the assembly and maintenance of eukaryotic cilia, we investigated patient fibroblasts and found significantly reduced frequency and length of primary cilia as compared to controls. Furthermore, we transiently knocked down ift122 in zebrafish embryos and observed the typical phenotype found in other models of ciliopathies. Because not all of our patients harbored mutations in IFT122, CED seems to be genetically heterogeneous. Still, by identifying CED as a ciliary disorder, our study suggests that the causative mutations in the unresolved cases most likely affect primary cilia function too.     

Analyses archéométriques dans la grotte ornée Mayenne-Sciences (Thorigné-en-Charnie, Mayenne)

Since 1998, a multidisciplinary team works on the study of the representations in the cave Mayenne-Sciences (Thorigné-en-Charnie, Mayenne). Particularly, there are trials for U-TH (TIMH) datations of the speleothems recovering the drawings and fossils of the bats; this would help to know at what date the decorated cave was closed. The studies already allowed to know better the black drawings, executed with a wooden charcoal crayon. Thus, it was possible to make removals which gave two dates from the Gravettian phase; this feeds again the discussion about the chronocultural position of this cave, on of the most septentrional caves we know.     

Rapid sympatric ecological differentiation of crater lake cichlid fishes within historic times

Background  

After a volcano erupts, a lake may form in the cooled crater and become an isolated aquatic ecosystem. This makes fishes in crater lakes informative for understanding sympatric evolution and ecological diversification in barren environments. From a geological and limnological perspective, such research offers insight about the process of crater lake ecosystem establishment and speciation. In the present study we use genetic and coalescence approaches to infer the colonization history of Midas cichlid fishes (Amphilophus cf. citrinellus) that inhabit a very young crater lake in Nicaragua-the ca. 1800 year-old Lake Apoyeque. This lake holds two sympatric, endemic morphs of Midas cichlid: one with large, hypertrophied lips (~20% of the total population) and another with thin lips. Here we test the associated ecological, morphological and genetic diversification of these two morphs and their potential to represent incipient speciation.     

Hypofractionated radiotherapy has the potential for second cancer reduction

Background and Purpose  

A model for carcinoma and sarcoma induction was used to study the dependence of carcinogenesis after radiotherapy on fractionation.