Isolation and characterisation of polychlorinated biphenyl (PCB) degrading fungi from a historically contaminated soil

Background  

Polychlorinated biphenyls (PCBs) are widespread toxic pollutants. Bioremediation might be an effective, cost competitive and environment-friendly solution for remediating environmental matrices contaminated by PCBs but it is still unsatisfactory, mostly for the limited biodegradation potential of bacteria involved in the processes. Very little is known about mitosporic fungi potential in PCB bioremediation and their occurrence in actual site historically contaminated soils. In the present study, we characterised the native mycoflora of an aged dump site soil contaminated by about 0.9 g kg^-1 of Aroclor 1260 PCBs and its changing after aerobic biotreatment with a commercial complex source of bacteria and fungi. Fungi isolated from the soil resulting from 120 days of treatment were screened for their ability to adsorb or metabolise 3 target PCBs.     

The MRX complex plays multiple functions in resection of Yku- and Rif2-protected DNA ends

The ends of both double-strand breaks (DSBs) and telomeres undergo tightly regulated 5' to 3' resection. Resection of DNA ends, which is specifically inhibited during the G1 cell cycle phase, requires the MRX complex, Sae2, Sgs1 and Exo1. Moreover, it is negatively regulated by the non-homologous end-joining component Yku and the telomeric protein Rif2. Here, we investigate the nuclease activities that are inhibited at DNA ends by Rif2 and Yku in G1 versus G2 by using an inducible short telomere assay. We show that, in the absence of the protective function of Rif2, resection in G1 depends primarily on MRX nuclease activity and Sae2, whereas Exo1 and Sgs1 bypass the requirement of MRX nuclease activity only if Yku is absent. In contrast, Yku-mediated inhibition is relieved in G2, where resection depends on Mre11 nuclease activity, Exo1 and, to a minor extent, Sgs1. Furthermore, Exo1 compensates for a defective MRX nuclease activity more efficiently in the absence than in the presence of Rif2, suggesting that Rif2 inhibits not only MRX but also Exo1. Notably, the presence of MRX, but not its nuclease activity, is required and sufficient to override Yku-mediated inhibition of Exo1 in G2, whereas it is required but not sufficient in G1. Finally, the integrity of MRX is also necessary to promote Exo1- and Sgs1-dependent resection, possibly by facilitating Exo1 and Sgs1 recruitment to DNA ends. Thus, resection of DNA ends that are protected by Yku and Rif2 involves multiple functions of the MRX complex that do not necessarily require its nuclease activity.     

Parasitic worms: knowledge, attitudes, and practices in Western Côte d'Ivoire with implications for integrated control

Background

In the developing world where parasitic worm infections are pervasive, preventive chemotherapy is the key strategy for morbidity control. However, local knowledge, attitudes, and practices (KAP) of parasitic worms are poorly understood, although such information is required for prevention and sustainable control.

Methods

We carried out KAP surveys in two rural communities of Côte d''Ivoire that were subjected to school-based and community-based research and control activities. We used qualitative and quantitative methods. The former included observations, in-depth interviews with key informants, and focus group discussions with school children and adults. Quantitative methods consisted of a structured questionnaire administered to household heads.

Principal Findings

Access to clean water was lacking in both communities and only a quarter of the households had functioning latrines. There was a better understanding of soil-transmitted helminthiasis than intestinal schistosomiasis, but community-based rather than school-based interventions appeared to improve knowledge of schistosomiasis. In the villages with community-based interventions, three-quarters of household interviewees knew about intestinal schistosomiasis compared to 14% in the village where school-based interventions were implemented (P<0.001). Whereas two-thirds of respondents from the community-based intervention village indicated that the research and control project was the main source of information, only a quarter of the respondents cited the project as the main source.

Conclusions/Significance

Preventive chemotherapy targeting school-aged children has limitations, as older population segments are neglected, and hence lack knowledge about how to prevent and control parasitic worm infections. Improved access to clean water and sanitation is necessary, along with health education to make a durable impact against helminth infections.     

Funerary practices of the Iberomaurusian population of Taforalt (Tafoughalt, Morocco, 11–12,000 BP): the case of Grave XII

The Iberomaurusian necropolis of Taforalt (Morocco, 11-12000 BP), excavated by Roche in the 1950s, contains 28 multiple graves. The funerary practices of the Taforalt population have been the focus of a previous work (Mariotti et al., 2009). In the absence of the excavation records of the necropolis, these funerary practices were investigated through the analysis of the contents of each grave and the distribution of intentionally modified specimens (ochre-dyeing, cut marks). Previous research has drawn particular attention to Grave XII (containing three male adults and two juveniles), where many intentionally modified specimens were identified. The present study focused specifically on the human remains recovered from Grave XII. Analysis of these remains has provided evidence of interventions, such as dismemberment and defleshing of the cadaver, and the use of ochre to colour the bones. Furthermore, the presence of lesions on two skulls suggests the possibility of intentional killing and cannibalism among the Taforalt population. This study further supports our previous impression of the complex and diversified funerary practices, characterising the social life of the Iberomaurusian population of Taforalt.     

Evaluation of Polymer Mucoadhesiveness by the Use of Acoustic Spectroscopy

An innovative and simple methodology has been developed and used for the evaluation of mucoadhesive properties of several polymers by means of sound speed measurements using high-resolution acoustic spectroscopy. In systems made of polymers in water, variations in hydration shell of polymeric chains determine changes of dispersions compressibility, and this phenomenon can be monitored by sound speed measurements. Four different polymers have been selected, namely PEG 6000, Carbopol 974, HPMC K4M, and Pectin 200/USP, all characterised by very different mucoadhesive properties. Samples made of each polymer alone (0.3–1.0% w/w) or in mixture with mucin (mucin fixed at 1.0% w/w) in water were investigated while using high-resolution ultrasonic spectrometer at two different frequencies (5.2 and 8.2 MHz). Polymer–mucin interaction was evaluated comparing experimental sound speed values of polymer–mucin samples with their theoretical values derived from the addition of sound speeds obtained while analysing each component alone. Results demonstrated the ability of the acoustic method to discriminate between mucoadhesive and no mucoadhesive polymer–mucin dispersions and allowed also the comparison between their mucoadhesive strengths. The study has therefore demonstrated the potential of using high-resolution ultrasonic spectroscopy to evaluate the polymers’ mucoadhesiveness, with the great advantage of testing small amount of samples even if opaque.     

MAL/VIP17, a New Player in the Regulation of NKCC2 in the Kidney

The renal-specific Na⁺-K⁺-2Cl⁻ cotransporter (NKCC2) is the major salt transport pathway of the apical membrane of the mammalian thick ascending limb of Henle''s loop. Here, we analyze the role of the tetraspan protein myelin and lymphocytes-associated protein (MAL)/VIP17 in the regulation of NKCC2. We demonstrated that 1) NKCC2 and MAL/VIP17 colocalize and coimmunoprecipitate in Lilly Laboratories cell porcine kidney cells (LLC-PK1) as well as in rat kidney medullae, 2) a 150-amino acid stretch of NKCC2 C-terminal tail is involved in the interaction with MAL/VIP17, 3) MAL/VIP17 increases the cell surface retention of NKCC2 by attenuating its internalization, and 4) this coincides with an increase in cotransporter phosphorylation. Interestingly, overexpression of MAL/VIP17 in the kidney of transgenic mice results in cysts formation in distal nephron structures consistent with the hypothesis that MAL/VIP17 plays an important role in apical sorting or in maintaining the stability of the apical membrane. The NKCC2 expressed in these mice was highly glycosylated and phosphorylated, suggesting that MAL/VIP17 also is involved in the stabilization of NKCC2 at the apical membrane in vivo. Thus, the involvement of MAL/VIP17 in the activation and surface expression of NKCC2 could play an important role in the regulated absorption of Na⁺ and Cl⁻ in the kidney.     

Conformation-assisted inhibition of protein-tyrosine phosphatase-1B elicits inhibitor selectivity over T-cell protein-tyrosine phosphatase

PTP-1B represents an attractive target for the treatment of type 2 diabetes and obesity. Given the role that protein phosphatases play in the regulation of many biologically relevant processes, inhibitors against PTP-1B must be not only potent, but also selective. It has been extremely difficult to synthesize inhibitors that are selective over the highly homologous TCPTP. We have successfully exploited the conservative Leu119 to Val substitution between the two enzymes to synthesize a PTP-1B inhibitor that is an order of magnitude more selective over TCPTP. Structural analyses of PTP-1B/inhibitor complexes show a conformation-assisted inhibition mechanism as the basis for selectivity. Such an inhibitory mechanism may be applicable to other homologous enzymes.     

Lymphocyte cytochrome c oxidase, cyclic GMP and cholinergic muscarinic receptors as peripheral indicators of carbon monoxide neurotoxicity after acute and repeated exposure in the rat

Changes in cerebral cytochrome oxidase (COX) activity, nitric oxide (NO)-cyclic GMP (cGMP) pathway and cholinergic muscarinic receptors (MRs) have been reported in rodents acutely exposed to carbon monoxide (CO). These endpoints measurable in lymphocytes may serve as peripheral markers of CO neurotoxicity. The early and delayed effects of repeated and acute in vivo CO inhalation were investigated on COX activity, cGMP formation and MR binding in rat brain and lymphocytes to assess whether each endpoint was similarly affected both centrally and peripherally. Male Wistar rats either inhaled 500 ppm CO, 6 h/day, 5 days/week, 4 weeks (repeated exposure) or 2,400 ppm, 1 h (single exposure). Neither treatment altered brain or lymphocyte COX activity 1 and 7 days post-treatment. Also ineffective were repeated and acute CO treatments towards (3)H-quinuclidinyl benzilate (QNB) binding to MRs in cerebral cortex, hippocampus, striatum, cerebellum (respective controls, mean+/-S.D.: 171 +/- 45, 245 +/- 53, 263 +/- 14 and 77 +/- 7 fmol/mg protein) and lymphocytes (24 +/- 10 fmol/million cells) at the same time points. In lymphocytes control cGMP levels averaged 1.98 +/- 0.99 pmol/mg protein under basal conditions, and 3.94 +/- 0.55 pmol/mg protein after NO-stimulation. One day after chronic treatment cessation, the CO-treated group displayed about a 50% decrease in both basal and NO-stimulated cGMP values, which persisted up to 7 days after, compared to air-exposed rats. Acutely, CO caused a delayed enhancement (+140%) of NO-induced activation of soluble guanylate cyclase. The finding that the NO-cGMP pathway is a target for the delayed effects of CO in peripheral blood cells is in accordance with our data in brain [Hernández-Viadel, M., Castoldi, A.F., Coccini, T., Manzo, L., Erceg, S., Felipo, V., 2004. In vivo exposure to carbon monoxide causes delayed impairment of activation of soluble guanylate cyclase by nitric oxide in rat brain cortex and cerebellum. Journal of Neurochemistry 89, 1,157-1,165], and supports the use of this peripheral endpoint as a biomarker of CO central effects.     

Long-lasting systemic bait markers for Eurasian badgers

This study was carried out to assess whether Rhodamine B, ethyl-iophenoxic acid (EtIPA), and propyl-iophenoxic acid (PrIPA) can be used as long-lasting systemic bait markers for free-living badgers (Meles meles). Between June and November 2003, these chemicals were incorporated into bait distributed around badger setts. Serum, hair, and whiskers from individually marked badgers were collected in the following 4 to 24 wk. Rhodamine B was detectable as fluorescent bands up to 24 wk after ingestion of the bait. Individual badgers were found positive for EtIPA and PrIPA up to 20 wk and 18 wk after exposure, respectively. This study indicates that Rhodamine B, PrIPA, and EtIPA could be used as long-lasting markers for badgers.