Dramatic changes in a phytoplankton community in response to local and global pressures: a 24‐year survey of the river Loire (France)

The impact of climate change and of other anthropogenic pressures on the structure and composition of phytoplankton communities of large European rivers remains poorly documented. Here we report the findings of a study of the changes in the phytoplankton community of the middle segment of the river Loire over the past 24 years. An attempt is made to distinguish between the impact of changes acting at the local scale and that of those acting more globally. A dramatic reduction in phytoplankton abundance was observed, particularly in the mid ‐1990s; this was concomitant with an increase in the relative proportion of cyanobacteria. At the same time, the phytoplankton community displayed increasing richness and diversity, and little change in its size structure. All these changes seem to be related to local changes, in particular to the reduction in phosphorus concentrations, as well as to changes in climate, throughout modifications in the river discharge and water temperature. Interestingly, herbicide contamination also appeared to be of particular importance in explaining the unexpected increase in the proportion of cyanobacteria in the phytoplankton community after the 1990s. These findings suggest that combinations of numerous anthropogenic pressures acting at different spatial and temporal scales have led to a mix of predictable and unpredictable changes occurring in the phytoplankton community of the river Loire, with probable consequences for the trophic networks in this river.     

Cumulative Risk of Bovine Mastitis Treatments in Denmark,Finland, Norway and Sweden

Data from the national dairy cow recording systems during 1997 were used to calculate lactation-specific cumulative risk of mastitis treatments and cumulative risk of removal from the herds in Denmark, Finland Norway and Sweden. Sweden had the lowest risk of recorded mastitis treatments during 305 days of lactation and Norway had the highest risk. The incidence risk of recorded mastitis treatments during 305 days of lactation in Denmark, Finland, Norway and Sweden was 0.177, 0.139, 0.215 and 0.127 for first parity cows and 0.228, 0.215, 0.358 and 0.204 for parities higher than three, respectively. The risk of a first parity cow being treated for mastitis was almost 3 times higher at calving in Norway than in Sweden. The period with the highest risk for mastitis treatments was from 2 days before calving until 14 days after calving and the highest risk for removal was from calving to 10 days after calving in all countries.The study clearly demonstrated differences in bovine mastitis treatment patterns among the Nordic countries. The most important findings were the differences in treatment risks during different lactations within each country, as well as differences in strategies with respect to the time during lactation mastitis was treated.     

Structure of the Pseudorabies Virus Capsid: Comparison with Herpes Simplex Virus Type 1 and Differential Binding of Essential Minor Proteins

The structure of pseudorabies virus (PRV) capsids isolated from the nucleus of infected cells and from PRV virions was determined by cryo-electron microscopy (cryo-EM) and compared to herpes simplex virus type 1 (HSV-1) capsids. PRV capsid structures closely resemble those of HSV-1, including distribution of the capsid vertex specific component (CVSC) of HSV-1, which is a heterodimer of the pUL17 and pUL25 proteins. Occupancy of CVSC on all PRV capsids is near 100%, compared to ~ 50% reported for HSV-1 C-capsids and 25% or less that we measure for HSV-1 A- and B-capsids. A PRV mutant lacking pUL25 does not produce C-capsids and lacks visible CVSC density in the cryo-EM-based reconstruction. A reconstruction of PRV capsids in which green fluorescent protein was fused within the N-terminus of pUL25 confirmed previous studies with a similar HSV-1 capsid mutant localizing pUL25 to the CVSC density region that is distal to the penton. However, comparison of the CVSC density in a 9-Å-resolution PRV C-capsid map with the available crystal structure of HSV-1 pUL25 failed to find a satisfactory fit, suggesting either a different fold for PRV pUL25 or a capsid-bound conformation for pUL25 that does not match the X-ray model determined from protein crystallized in solution. The PRV capsid imaged within virions closely resembles C-capsids with the addition of weak but significant density shrouding the pentons that we attribute to tegument proteins. Our results demonstrate significant structure conservation between the PRV and HSV capsids.     

Disease pathways at the Rat Genome Database Pathway Portal: genes in context-a network approach to understanding the molecular mechanisms of disease

Background

Biological systems are exquisitely poised to respond and adjust to challenges, including damage. However, sustained damage can overcome the ability of the system to adjust and result in a disease phenotype, its underpinnings many times elusive. Unraveling the molecular mechanisms of systems biology, of how and why it falters, is essential for delineating the details of the path(s) leading to the diseased state and for designing strategies to revert its progression. An important aspect of this process is not only to define the function of a gene but to identify the context within which gene functions act. It is within the network, or pathway context, that the function of a gene fulfills its ultimate biological role. Resolving the extent to which defective function(s) affect the proceedings of pathway(s) and how altered pathways merge into overpowering the system's defense machinery are key to understanding the molecular aspects of disease and envisioning ways to counteract it. A network-centric approach to diseases is increasingly being considered in current research. It also underlies the deployment of disease pathways at the Rat Genome Database Pathway Portal. The portal is presented with an emphasis on disease and altered pathways, associated drug pathways, pathway suites, and suite networks.

Results

The Pathway Portal at the Rat Genome Database (RGD) provides an ever-increasing collection of interactive pathway diagrams and associated annotations for metabolic, signaling, regulatory, and drug pathways, including disease and altered pathways. A disease pathway is viewed from the perspective of networks whose alterations are manifested in the affected phenotype. The Pathway Ontology (PW), built and maintained at RGD, facilitates the annotations of genes, the deployment of pathway diagrams, and provides an overall navigational tool. Pathways that revolve around a common concept and are globally connected are presented within pathway suites; a suite network combines two or more pathway suites.

Conclusions

The Pathway Portal is a rich resource that offers a range of pathway data and visualization, including disease pathways and related pathway suites. Viewing a disease pathway from the perspective of underlying altered pathways is an aid for dissecting the molecular mechanisms of disease.

     

How useful is the assessment of lymphatic vascular density in oral carcinoma prognosis?

Background

Lymphatic vessels are major routes for metastasis in head and neck squamous cell carcinoma (HNSCC), but lymphatic endothelial cells (LECs) are difficult to recognize in tumor histological sections. D2-40 stains podoplanin, a molecule expressed in LECs, however, the potential prognostic usefulness of this molecule is not completely understood in HNSCC. We aimed to investigate the value of assessing peritumoral and intratumoral lymphatic vessel density (LVD) as prognostic marker for HNSCC.

Methods

Thirty-one cases of HNSCC were stained for D2-40 and CD31. LVD and blood vessel density (BVD) were assessed by counting positive reactions in 10 hotspot areas at ×200 magnification.

Results

D2-40 was specific for lymphatic vessels and did not stain blood vascular endothelial cells. LECs showed more tortuous and disorganized structure in intratumoral lymphatic vessels than in peritumoral ones. No statistical differences were observed between peritumoral-LVD and intratumoral-LVD or between peritumoral-BVD and intratumoral-BVD. Tumor D2-40 staining was positively associated with lymphatic vessel invasion (p = 0.011).

Conclusion

LVD is a powerful marker for HNSCC prognosis. We found significant differences in peritumoral and intratumoral D2-40 immunoreactivity, which could have important implications in future therapeutic strategies and outcome evaluation.

     

Heterologous expression of bacteriocin E-760 in Chlamydomonas reinhardtii and functional analysis

The use of antimicrobial peptides (AMPs) synthesized by bacteria (bacteriocins) is an alternative for combating multidrug resistant bacterial strains and their production by recombinant route is a viable option for their mass production. The bacteriocin E-760 isolated from the genus Enterococcus sp. has been shown to possess inhibitory activity against Gram-negative and Gram-positive bacteria. In this study, the expression of a chimeric protein coding for E-760 in the nucleus of C. reinhardtii was evaluated, as well as, its antibacterial activity. The synthetic gene E-760S was inserted into the genome of C. reinhardtii using Agrobacterium tumefaciens. A transgenic line was identified in TAP medium with hygromycin and also by PCR. The increment in the culture medium temperature of the transgenic strain at 35 °C for 10 minutes, increased the production level of the recombinant protein from 0.14 (Noninduced culture, NIC) to 0.36% (Induced culture, IC) of total soluble proteins (TSP); this was quantified by an ELISA assay. Recombinant E-760 possesses activity against Staphylococcus aureus in 0.34 U log, Streptococcus agalactiae in 0.48 U log, Enterococcus faecium in 0.36 U log, Pseudomonas aeruginosa in 2 U log and for Klebsiella pneumoniae, the activity was 0.07 U log. These results demonstrate that the nucleus transformation of C. reinhardtii can function as a stable expression platform for the production of the synthetic gene E-760 and it can potentially be used as an antibacterial agent.     

Characterization of the <Emphasis Type="Italic">Trichomonas vaginalis</Emphasis> surface-associated AP65 and binding domain interacting with trichomonads and host cells

Background  

AP65 is a prominent adhesin of Trichomonas vaginalis that mediates binding of parasites to host vaginal epithelial cells (VECs). AP65 with no secretion signal sequence, membrane targeting peptide, and anchoring motif was recently found to be secreted.     

Imagerie et bilan d'une infertilité masculine

A male cause is responsible in near 50% of infertilities. The radiologist takes place in a multidisciplinary management, after clinical and biological screening, which distinguishes:

- excretory infertilities, of which some causes are curable. Transrectal sonography (TRUS) and scrotal sonography are the first tests. In case of epididymal obstacle, scrotal abnormalities may correspond to constitutional or acquired causes; TRUS is normal. TRUS usually identifies congenital bilateral absence of vas deferens; without renal agenesia, a genital form of cystic fibrosis must be evocated. In case of distal obstacles, TRUS may be completed with MRI, especially in case of voluminous cystic tumors. Vasography, which directly shows was deferens patency, is required to accurately diagnose obstruction when ultrasound is not conclusive; vasography must be integrated in a surgical strategy.

- secretory azoospermies, from gonadic or hypothalamo-hypophyseal causes. Scrotal sonography may complete clinical examination. When hypothalamo-hypophyseal axis must be explored, MRI is the reference test.

- oligo-astheno-teratospermies, where infertilities are often mixed, with various male factors.

Three groups must be explored: hyperprolactinemies (MRI); chronic genital infection (ultrasound); varicoceles; Doppler color ultrasound may help to the detection; spermatic phlebography produce a pretherapeutic cartography, and may be the first step of a percutaneous sclerotherapy.     

SKPDB: a structural database of shikimate pathway enzymes

Background  

The functional and structural characterisation of enzymes that belong to microbial metabolic pathways is very important for structure-based drug design. The main interest in studying shikimate pathway enzymes involves the fact that they are essential for bacteria but do not occur in humans, making them selective targets for design of drugs that do not directly impact humans.     

Thrombin receptors activate G(o) proteins in endothelial cells to regulate intracellular calcium and cell shape changes

Thrombin receptors couple to G(i/o), G(q), and G(12/13) proteins to regulate a variety of signal transduction pathways that underlie the physiological role of endothelial cells in wound healing or inflammation. Whereas the involvement of G(i), G(q), G(12), or G(13) proteins in thrombin signaling has been investigated extensively, the role of G(o) proteins has largely been ignored. To determine whether G(o) proteins could contribute to thrombin-mediated signaling in endothelial cells, we have developed minigenes that encode an 11-amino acid C-terminal peptide of G(o1) proteins. Previously, we have shown that use of the C-terminal minigenes can specifically block receptor activation of G protein families (). In this study, we demonstrate that G(o) proteins are present in human microvascular endothelial cells (HMECs). Moreover, we show that thrombin receptors can stimulate [(35)S]guanosine-5'-O-(3-thio)triphosphate binding to G(o) proteins when co-expressed in Sf9 membranes. The potential coupling of thrombin receptors to G(o) proteins was substantiated by transfection of the G(o1) minigene into HMECs, which led to a blockade of thrombin-stimulated release of [Ca(2+)](i) from intracellular stores. Transfection of the beta-adrenergic kinase C terminus blocked the [Ca(2+)](i) response to the same extent as with G(o1) minigene peptide, suggesting that this G(o)-mediated [Ca(2+)](i) transient was caused by Gbetagamma stimulation of PLCbeta. Transfection of a G(i1/2) minigene had no effect on thrombin-stimulated [Ca(2+)](i) signaling in HMEC, suggesting that Gbetagamma derived from G(o) but not G(i) could activate PLCbeta. The involvement of G(o) proteins on events downstream from calcium signaling was further evidenced by investigating the effect of G(o1) minigenes on thrombin-stimulated stress fiber formation and endothelial barrier permeability. Both of these effects were sensitive to pertussis toxin treatment and could be blocked by transfection of G(o1) minigenes but not G(i1/2) minigenes. We conclude that the G(o) proteins play a role in thrombin signaling distinct from G(i1/2) proteins, which are mediated through their Gbetagamma subunits and involve coupling to calcium signaling and cytoskeletal rearrangements.