Simultaneous nitrification, denitrification, and phosphorus removal from nutrient-rich industrial wastewater using granular sludge

The biological removal of nitrogen and phosphorus from nutrient-rich abattoir wastewater using granular sludge has been investigated. A lab-scale sequencing batch reactor, seeded with granular sludge developed using synthetic wastewater, was operated for 13 months under alternating anaerobic and aerobic conditions. It is demonstrated that the granules could be sustained and indeed further developed with the use of abattoir wastewater. The organic, nitrogen, and phosphorus loading rates applied were 2.7 gCOD L(-1) day(-1), 0.43 gN L(-1) day(-1), and 0.06 gP L(-1) day(-1), respectively. The removal efficiency of soluble COD, soluble nitrogen and soluble phosphorus were 85%, 93%, and 89%, respectively. However, the high suspended solids in the effluent limited the overall removal efficiency to 68%, 86%, and 74% for total COD, TN, and TP, respectively. This good nutrient removal was achieved through the process known as simultaneous nitrification, denitrification, and phosphorus removal, likely facilitated by the presence of large anoxic zones in the center of the granules. The removal of nitrogen was likely via nitrite optimizing the use of the limited COD available in the wastewater. Accumulibacter spp. were found to be responsible for most of the denitrification, further reducing the COD requirement for nitrogen and phosphorus removal. Mineral precipitation was evaluated and was not found to significantly contribute to the overall nutrient removal. It is also shown that the minimum HRT in a granular sludge system is not governed by the sludge settleability, as is the case with floccular sludge systems, but likely by the limitations associated with the transfer of substrates in granules.     

Structural characterization of a putative endogenous metal chelator in the periplasmic nickel transporter NikA

Escherichia coli and related bacteria require nickel for the synthesis of hydrogenases, enzymes involved in hydrogen oxidation and proton reduction. Nickel transport to the cytoplasm depends on five proteins, NikA-E. We have previously reported the three-dimensional structure of the soluble periplasmic nickel transporter NikA in a complex with FeEDTA(H 2O) (-). We have now determined the structure of EDTA-free NikA and have found that it binds a small organic molecule that contributes three ligands to the coordination of a transition metal ion. Unexpectedly, His416, which was far from the metal-binding site in the FeEDTA(H 2O) (-)-NikA complex, becomes the fourth observed ligand to the metal. The best match to the omit map electron density is obtained for butane-1,2,4-tricarboxylate (BTC). Our attempts to obtain a BTC-Ni-NikA complex using apo protein and commercial reagents resulted in nickel-free BTC-NikA. Overall, our results suggest that nickel transport in vivo requires a specific metallophore that may be BTC.     

Seventeen new exon‐primed intron‐crossing polymerase chain reaction amplifiable introns in fish

We used exon‐primed, intron‐crossing polymerase chain reaction (EPIC‐PCR) amplification to assay variation in nuclear loci in some teleost fishes (Carangidae, Centropomidae, Chaetodontidae, Clupeidae, Holocentridae, Moronidae, Mullidae, Pomacentridae, Scombridae, Siganidae). We designed primers in the conserved regions flanking splice sites of consecutive exons of different genes, allowing the amplification of 17 putative introns. Among the satisfactory amplified systems, 14 showed length polymorphism with 2–14 alleles.     

Les problemes d'erection: une souffrance encore trop souvent cachee

Many epidemiological studies have demonstrated the high prevalence of erectile dysfunction, particularly among aging males and patients with chronic diseases. Many of these studies, using an objective methodology, showed that this problem induces major suffering for the patient and his partner. This suffering results less from loss of sexual pleasure than from loss of self-esteem, humiliation or guilt of being “impotent”, and from the consequences on the relationship of the patient's modified personality and attitudes (introversion, irritability, avoidance of tenderness and intimacy). These problems are also worsened by the female partner, who questions her own femininity, related, to confusion between loss of erection and lack of desire. The impact of erectile dysfunction extends well beyond sexual function, as it constitutes a real identity problem for the man, affecting his relational and work life (loss of dynamism and self-confidence). Many objective studies have demonstrated significant improvement of various quality of life parameters after effective treatment of erectile problems with intracavernosal injections or tablets They also have shown significant improvement of global quality of life (and not only sexual quality of life) and many psychological parameters (anxiety, depression, self-confidence in sexual and marital relationships and social and work life, hostility and interrelational sensitivity). Global health indices are also improved. Despite the suffering due to erectile problems, and the fact these problems can be effectively treated, few men mention these problems to their general practitioner. Many surveys, estimate between 5 and 30% the percentage of men with erectile dysfunction seeking medical attention, although they also reveal that a higher proportion would like to be helped. Because of religious and sociocultural taboos and their shame and fear of being judged or that their problem will be revealed, men are embarrassed to raise this question. Other causes are also involved in this phenomenon: fear that their request will be rejected by the doctor, or the belief that no treatments are available for this type of problem, or that they have to accept this problem as an inevitable part of physiological aging. Surveys confirm that patients would like their doctor to question them about their sexual functioning. This appears to be all the more desirable in that erectile problems are often due to endothelial dysfunction with may also affect other vessels such as coronary arteries. The diagnosis of these disorders could help to identify and correct the risks factors responsible for both types of this disease.     

Induction of anterior neural fates in the ascidian Ciona intestinalis

The sensory vesicle of ascidians is thought to be homologous to the vertebrate forebrain and midbrain (Development 125 (1998) 1113). Here we report the isolation of two sensory vesicle markers in the ascidian Ciona intestinalis, which are homologs of vertebrate otx and gsx homeobox genes. By using these markers to analyze the induction of anterior neural tissue in Ciona, we find that the restriction of anterior neural fate to the progeny of the anterior animal blastomeres is due to a combination of two factors. The vegetal blastomeres show a differential inducing activity along the anterior-posterior axis, while the competence to respond to this inducing signal is markedly higher in the anterior animal blastomeres than in the posterior animal blastomeres. This differential competence to respond is also observed in response to bFGF, a candidate neural inducer in ascidians (J. Physiol. 511.2 (1998) 347) and can be detected by the gastrula stage. Our results, however, indicate that bFGF can only induce a subset of the responses of the endogenous inducer, suggesting that additional signals in the embryo are necessary to induce a fully patterned nervous system.     

Synthesis of peptides by the solid-phase method. IV. Des-Arg(9)-bradykinin and analogs

We have synthesized a series of 19 analogs of the octapeptide fragment of bradykinin (BK), des-Arg 9-bradykinin, in order to perform a structure-activity study of this peptide on the newly discovered B1 receptor of bradykinin. The first time, each residue of the octapeptide was replaced by L-alanine to pinpoint biologically important residues. Thereafter, both phenylalanine residues in positions 5 and 8 were substituted by L-tyrosine methyl ether, L-cyclohexylalanine, D-phenylalanine, and L-leucine. This paper describes the synthesis of the analogs by the solid phase method. A Beckman peptide synthesizer was used to assemble the peptides on the resin support. Couplings were performed by the symmetrical anhydribe procedure. After cleavage with liquid HF, the peptides were purified by ion-exchange chromatography on carboxymethyl-cellulose and by gel filtration on Bio-Gel P2 resin. The purity of the octapeptides was then checked by tic, paper electrophoresis, amino acid analysis, and elemental analysis. The new peptides were tested on the rabbit aorta in order to evaluate their kinin-like activities and to see if they act as antagonist. The results of the biological assays are discussed in terms of structure-activity relationships.     

Intérêt de l’utilisation de la Prostaglandine El pour le pharmacodoppler

Doppler investigation play a more and more important role among non invasive investigations to detect penile arterial obstruction because it is simple and costless. However, continuous doppler system gives few reliable data. Pulsed doppler allows more precise investigations, reliably detecting deep vessels as cavernous arteries and, for 2nd generation system, allowing to quantify functional parameters. The association of high definition echography and colour doppler system allows to detect vessels in a more reliable and faster way, to measure arterial diameter, and reduces artefacts due to the vessel axis-probe axis angle. Nevertheless, these different investigations only give reliable and reproducible results when combined to intracavernous injection (ICI) of vasoactive drug (pharmacoldoppler). This ICI makes this procedure semi invasive and involves the risk of priapism. But it increases sensibility and specificity of the investigation by detecting arterial stenosis which are not evident in a basal state, by suggesting veno-occlusive dysfunction, and by eliminating vaso constriction due to stress. We have however to remind that, in some cases, stress can inhibit the response to ICI and so falsify pharmacodoppler results. In our center, we regularly use pulsed doppler anlysis after ICI of 10 μg of prostaglandin E1 (PGE1). The use of PGE1 increases the safety and the reliability of the investigation (less false negative results). The most reliable criteria for determination of the arterial factor seem to be the peak systolic velocity, the resistance index measured 15 minutes after ICI to appreciate the veno-occlusive factor