Relationships between trophic organization of benthic communities and organic matter content in Tyrrhenian Sea sediments

The organic content of sediments, often considered as an important trophic source for the benthos, can be used as a measurement of the trophic status of marine ecosystems. Soft-bottom communities were studied between Leghorn and Elba Island, from 5 to 500 m depth. Total biomass and trophic structure (percent dominance of trophic guilds) were related to organic carbon content and C/N ratio of sediments. Sediment organic matter, depending on its quantity and quality, could act as a food source or a stress source for the community.     

The primary quinone acceptor and the membrane-bound c-type cytochromes of the halophilic purple nonsulfur bacterium Rhodospirillum salinarum: A spectroscopic and thermodynamic study

The mid-point potential (Em_7.0) of the primary quinone acceptor (Qa) and the biochemical features (Em_7.0 and apparent molecular mass, MM) of the membrane bound c-type cytochromes (cyt) involved in photosynthetic electron transfer of the halophilic phototrophic bacterium Rhodospirillum (Rs.) salinarum were determined. A tetrahemic RC bound cytochrome was found (MM of 39.8 kDa) with Em_7.0 of the hemes equal to +304, +98, +21, –134 (± 8) mV as determined by dark equilibrium redox titrations in the isolated purified form. The highest potential heme (Em_7.0 = +304 mV, band at 556 nm) was able to reduce the photo-oxidized reaction center (P⁺) in a sub-millisecond ( 20 s) time scale reaction, acting most likely as the direct electron donor to P⁺). The midpoint potential of the primary electron donor (Em_7.0 = + 455 mV) was found to be close to that reported for the primary donor of the non-halophilic Rhodospirillum species Rs. rubrum, whereas the quinone primary electron acceptor (Qa) was different showing the spectral features of a menaquinone molecule with Em_7.0 at –128 (± 5) mV. A membrane bound c-type heme with Em_7.0 of 259 (± 1) and MM of 40 kDa was also isolated and referred to an orthodox cytochrome c₁). The present data on the photosynthetic apparatus, along with the previous results on the respiratory system [Moschettini et al. (1997) Arch Microbiol 168: 302-309], suggest that Rs. salinarum is biochemically distinct from Rs. rubrum, the most representative specie of the genus.     

Asaia,a versatile acetic acid bacterial symbiont,capable of cross‐colonizing insects of phylogenetically distant genera and orders

Bacterial symbionts of insects have been proposed for blocking transmission of vector‐borne pathogens. However, in many vector models the ecology of symbionts and their capability of cross‐colonizing different hosts, an important feature in the symbiotic control approach, is poorly known. Here we show that the acetic acid bacterium Asaia, previously found in the malaria mosquito vector Anopheles stephensi, is also present in, and capable of cross‐colonizing other sugar‐feeding insects of phylogenetically distant genera and orders. PCR, real‐time PCR and in situ hybridization experiments showed Asaia in the body of the mosquito Aedes aegypti and the leafhopper Scaphoideus titanus, vectors of human viruses and a grapevine phytoplasma respectively. Cross‐colonization patterns of the body of Ae. aegypti, An. stephensi and S. titanus have been documented with Asaia strains isolated from An. stephensi or Ae. aegypti, and labelled with plasmid‐ or chromosome‐encoded fluorescent proteins (Gfp and DsRed respectively). Fluorescence and confocal microscopy showed that Asaia, administered with the sugar meal, efficiently colonized guts, male and female reproductive systems and the salivary glands. The ability in cross‐colonizing insects of phylogenetically distant orders indicated that Asaia adopts body invasion mechanisms independent from host‐specific biological characteristics. This versatility is an important property for the development of symbiont‐based control of different vector‐borne diseases.     

Synthesis,biological assays and QSAR studies of N-(9-benzyl-2-phenyl-8-azapurin-6-yl)-amides as ligands for A1 adenosine receptors

2-Phenyl-9-benzyl-8-azapurines, bearing at the 6 position an amido group interposed between the 8-azapurine moiety and an alkyl or a substituted phenyl group, have been synthesised and assayed as ligands for adenosine receptors. All the compounds show high affinity for the A₁ adenosine receptor, and many of them also show a good selectivity for A₁ with respect to A_2A and A₃ adenosine receptors. Based on the quite rich library containing such compounds and relevant biological data, QSAR models, able to rationalise the results and to give a quantitative estimate of the observed trends were also developed. The obtained models can assist in the design of new compounds selectively active on A₁ adenosine receptor.     

Infant hybrids in a newly formed mixed-species group of howler monkeys (Alouatta guariba clamitans and Alouatta caraya) in northeastern Argentina

Natural hybridisation between species has been reported in several primate taxa. In the Neotropics, there is increasing evidence of this phenomenon in howler monkeys (genus Alouatta) in contact zones between species. We describe the first known case of formation of a mixed-species group, and two cases of putative infant hybrids between the brown howler (Alouatta guariba clamitans) and the black howler (A. caraya) in Misiones, Argentina. For 2 years, we followed a group consisting of one adult male and two adult female brown howlers and one adult female black howler. The adult female black howler was observed to copulate twice with brown howler males, and never with black howler males. In December 2006, this female was carrying an infant with a hybrid morphotype. This infant died at approximately 1.5 months of age. In November 2007, the same female had another putative hybrid newborn. This infant male died together with all members of his group during a yellow fever outbreak in early 2008. The lower frequency of mixed-species groups and hybrids at our site compared with other contact zones reported in the literature, suggests that the incidence of natural hybridisation between howler species differs depending on local factors such as population demography and landscape fragmentation.     

Real-time PCR for detection and quantification of the biocontrol agent Trichoderma atroviride strain SC1 in soil

Trichoderma (Hypocreales, Ascomycota) is a widespread genus in nature and several Trichoderma species are used in industrial processes and as biocontrol agents against crop diseases. It is very important that the persistence and spread of microorganisms released on purpose into the environment are accurately monitored. Real-time PCR methods for genus/species/strain identification of microorganisms are currently being developed to overcome the difficulties of classical microbiological and enzymatic methods for monitoring these populations. The aim of the present study was to develop and validate a specific real-time PCR-based method for detecting Trichoderma atroviride SC1 in soil. We developed a primer and TaqMan probe set constructed on base mutations in an endochitinase gene. This tool is highly specific for the detection and quantification of the SC1 strain. The limits of detection and quantification calculated from the relative standard deviation were 6000 and 20,000 haploid genome copies per gram of soil. Together with the low throughput time associated with this procedure, which allows the evaluation of many soil samples within a short time period, these results suggest that this method could be successfully used to trace the fate of T. atroviride SC1 applied as an open-field biocontrol agent.     

The fragile X syndrome protein represses activity-dependent translation through CYFIP1, a new 4E-BP

Strong evidence indicates that regulated mRNA translation in neuronal dendrites underlies synaptic plasticity and brain development. The fragile X mental retardation protein (FMRP) is involved in this process; here, we show that it acts by inhibiting translation initiation. A binding partner of FMRP, CYFIP1/Sra1, directly binds the translation initiation factor eIF4E through a domain that is structurally related to those present in 4E-BP translational inhibitors. Brain cytoplasmic RNA 1 (BC1), another FMRP binding partner, increases the affinity of FMRP for the CYFIP1-eIF4E complex in the brain. Levels of proteins encoded by known FMRP target mRNAs are increased upon reduction of CYFIP1 in neurons. Translational repression is regulated in an activity-dependent manner because BDNF or DHPG stimulation of neurons causes CYFIP1 to dissociate from eIF4E at synapses, thereby resulting in protein synthesis. Thus, the translational repression activity of FMRP in the brain is mediated, at least in part, by CYFIP1.     

Distinct roles of RalA and RalB in the progression of cytokinesis are supported by distinct RalGEFs

The Ras family G-proteins RalA and RalB make critical non-overlapping contributions to the generation of a tumorigenic regulatory network, supporting bypass of the normal restraints on both cell proliferation and survival. The Sec6/8 complex, or exocyst, has emerged as a principal direct effector complex for Ral GTPases. Here, we show that RalA and RalB support mitotic progression through mobilization of the exocyst for two spatially and kinetically distinct steps of cytokinesis. RalA is required to tether the exocyst to the cytokinetic furrow in early cytokinesis. RalB is then required for recruitment of the exocyst to the midbody of this bridge to drive abscission and completion of cytokinesis. The collaborative action of RalA and RalB is specified by discrete subcellular compartmentalization and unique pairs of RalGEF proteins that provide inputs from both Ras-family protein-dependent and protein-independent regulatory cues. This suggests that Ral GTPases integrate diverse upstream signals to choreograph multiple roles for the exocyst in mitotic progression.     

High-Throughput Multiplex Single-Nucleotide Polymorphism (SNP) Analysis in Genes Involved in Methionine Metabolism

Hyperhomocysteinemia is a well-known independent marker factor for atherothrombotic diseases and may result from acquired and genetic influences. Several polymorphisms are suspected to be associated with hyperhomocysteinemia, but data are limited and inconsistent. High-throughput genotyping technologies, such as GenomeLab SNPStream, are now available. Moreover, an appropriate selection of SNPs to be analyzed could represent a strong resource to define the role of genetic risk factors. We developed a multiplex PCR-oligonucleotide extension approach by GenomeLab platform. We selected 72 SNPs based on their putative function and frequency in the candidate genes AHCY, BHMT, BHMT2, CBS, ENOSF1, FOLH1, MTHFD1, MTHFR, MTR, MTRR, NNMT, PON1, PON2, SLC19A1, SHMT1, TCN2, and TYMS. We were able to analyze 57 of the SNPs (79%). For MTHFR C677T and A1298C and MTR A2756G SNPs, we compared data obtained with an electronic microchip technology and found 99.2% concordance. We also performed a haplotype analysis. This approach could represent a useful tool to investigate the genotype-phenotype correlation and the association of these genes with hyperhomocysteinemia and correlated diseases.