Norspermidine is not a self-produced trigger for biofilm disassembly

SummaryFormation of Bacillus subtilis biofilms, consisting of cells encapsulated within an extracellular matrix of exopolysaccharide and protein, requires the polyamine spermidine. A recent study reported that (1) related polyamine norspermidine is synthesized by B. subtilis using the equivalent of the Vibrio cholerae biosynthetic pathway, (2) exogenous norspermidine at 25 μM prevents B. subtilis biofilm formation, (3) endogenous norspermidine is present in biofilms at 50–80 μM, and (4) norspermidine prevents biofilm formation by condensing biofilm exopolysaccharide. In contrast, we find that, at concentrations up to 200 μM, exogenous norspermidine promotes biofilm formation. We find that norspermidine is absent in wild-type B. subtilis biofilms at all stages, and higher concentrations of exogenous norspermidine eventually inhibit planktonic growth and biofilm formation in an exopolysaccharide-independent manner. Moreover, orthologs of the V. cholerae norspermidine biosynthetic pathway are absent from B. subtilis, confirming that norspermidine is not physiologically relevant to biofilm function in this species

Synthetic recognition systems : self-assembly and metal chelation

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1994.Includes bibliographical references.by Neil R. Branda.Ph.D

Immunodepletion in xenotransplantation

Xenograft transplantation is perhaps the most immunologically difficult problem in transplantation today. An overwhelming hyperacute rejection reaction (HAR) occurs within minutes of organ implantation. Preformed antibodies are thought to initiate this process. We used a pig-to-dog renal xenograft transplant model and investigated methods of decreasing the severity of hyperacute rejection. Female pigs weighing 15-20 kg were used as donors. Recipients were mongrel dogs weighing 15-25 kg. Experimental dogs were all given a number of treatments of IgG depletion using an antibody removal system (Dupont-Excorim). This machine immunoadsorbs plasma against a column containing immobilized staphylococcal protein A, which is known to bind the IgG Fc receptor. An 84% reduction in the IgG levels and a 71% reduction in IgM levels was achieved. Postoperative assessment was made of urine output, time to onset of HAR, and histopathological examination of the rejected kidneys. Although cross-matches between donor lymphocytes and recipient sera remained strongly positive in the treated dogs, there was a two- to fourfold reduction in the titers. The time to onset of HAR was prolonged in the experimental group, and the urine output was increased slightly. The histopathologic changes in the experimental group generally showed signs of HAR, but of less intensity than in the nonimmunodepleted control group. © 1990 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted

Capacity building in stakeholders around Detroit River fish consumption advisory issues

Abstract The Detroit River is an international water body that has several fish consumption advisories for contaminants that affect human health and economic revenue for the USA and Canada. Despite the importance of these advisories, little progress has been made in developing effective management strategies or coordinating monitoring, research, and policy efforts between the 2 nations. We engaged 44 stakeholder organizations to increase community capacity on these issues for the Detroit River. We assessed capacity with key informant interviews and a network survey. Our analysis identified weak ties in information sharing and collaboration between countries. We used this information to improve stakeholder capacity, which included forming working groups that focused on system analysis, identification of priority issues, and definitions of organizational roles. Outcomes included outreach materials addressing environmental-justice issues and risk-analysis models of polychlorinated biphenyl (PCB) body burdens in fish. Our assessment of workshop participants with a longitudinal survey indicated that we increased network capacity and issue awareness in our stakeholders by providing new ways for them to work together. The engagement of stakeholders also improved research outcomes. By identifying stakeholder concerns related to scientific questions about consumption advisories early in the process, researchers were able to direct their efforts to generating translational research that better addressed stakeholder needs

Calidad del agua de la subcuenca baja del río David y su impacto sobre la salud pública.

Water quality in the lower river basin of David was assessed for the years 2013 and 2014. The water quality index (WQI) proposed by the National Sanitation Foundation (NSF) was used. The parameters analyzed were BOD5, fecal coliform, turbidity, dissolved oxygen, pH, nitrates, phosphates and total solids. Fecal coliforms are classified as poor quality for the four monitored sites. The sampling site less WQI was Rondon. Global WQIfor 2013 was 72.96 while 2014 was 76.73. Low quality sub-basin is classified as good due to the influence of the pH, DO parameters, nitrates and phosphates rated as excellent; however, the main factor of deterioration is fecal coliform contamination as they were detected in amounts exceeding the limits established by Executive Decree No.75 (≤ 250UFC/100 mL) therefore, these waters are not suitable for any kind recreational activity direct contact.D. Rovira et al/ Calidaddel agua...Water quality in the lower river basin of David was assessed for the years 2013 and 2014. The water quality index (WQI) proposed by the National Sanitation Foundation (NSF) was used. The parameters analyzed were BOD5, fecal coliform, turbidity, dissolved oxygen, pH, nitrates, phosphates and total solids. Fecal coliforms are classified as poor quality for the four monitored sites. The sampling site less WQI was Rondon. Global WQIfor 2013 was 72.96 while 2014 was 76.73. Low quality sub-basin is classified as good due to the influence of the pH, DO parameters, nitrates and phosphates rated as excellent; however, the main factor of deterioration is fecal coliform contamination as they were detected in amounts exceeding the limits established by Executive Decree No.75 (≤ 250UFC/100 mL) therefore, these waters are not suitable for any kind recreational activity direct contact.D. Rovira et al/ Calidaddel agua..

In vivo mutations in human blood cells: Biomarkers for molecular epidemiology

Mutations arising in vivo in recorder genes of human blood cells provide biomarkers for molecular epidemiology by serving as surrogates for cancer-causing genetic changes. Current markers include mutations of the glycophorin-A (GPA) or hemoglobin (Hb) genes, measured in red blood cells, or mutations of the hypoxanthine-guanine phosphoribosyltransferase (hprt) or HLA genes, measured in T-lymphocytes. Mean mutant frequencies (variant frequencies) for normal young adults are approximately: Hb (4 x10-8) < hprt (5 x 10-6) = GPA (10 x 10-6) <HLA (30 x 10-6). Mutagen-exposed individuals show decided elevations. Molecular mutational spectra are also being defined. For the hprt marker system, about 15% of background mutations are gross structural alterations of the hprt gene (e.g., deletions); the remainder are point mutations (e.g., base substitutions or frameshifts). Ionizing radiations result in dose-related increases in total gene deletions. Large deletions may encompass several megabases as shown by co-deletions of linked markers. Possible hprt spectra for defining radiation and chemical exposures are being sought. In addition to their responsiveness to environmental mutagens/carcinogens, three additional findings suggest that the in vivo recorder mutations are relevant in vivo surrogates for cancer mutations. First, a large fraction of GPA and HLA mutations show exchanges due to homologous recombination, an important mutational event in cancer. Second, hprt mutations arise preferentially in dividing T-cells, which can accumulate additional mutations in the same clone, reminiscent of the multiple hits required in the evolution of malignancy. Finally, fetal hprt mutations frequently have characteristic deletions of hprt exons 2 and 3, which appear to be mediated by the VDJ recombinase that rearranges the T-cell receptor genes during thymic ontogeny. Illegitimate events such as these also appear to occur in human leukemias

El agua, elemento clave para la seguridad alimentaria. Estudio de caso: calidad del agua de consumo de urbanizaciones de David y Dolega.

Plus (+) Economía:ISSN2411-0353 -ISSN-L2644-4046|Vol.6. Núm. 2, Junio –Noviembre 2018AbstractThe quality of water for human consumption was evaluated in seven house developments in the districts of David and Dolega, to contribute to food safety. The study type was descriptive and it was carried out between the years 2016-2018. Chemical, physical and microbiological parameters were evaluated, following standardized analysis techniques. The results show that in general, all the parameters studied were within the permissible values in the Technical Regulation DGNTI-COPANIT 23-395-99(as per Acronym in Spanish),except residual chlorine, this indicates that it is necessary to guarantee the application and monitoring of chlorine in the storage tank. The Panamanian standard establishes a maximum level of 1,5 mg/L and a minimum residual of 0,8 mg/L in the water. No presence of total coliforms was reported in six of the seven house developments evaluated.Plus (+) Economía:ISSN2411-0353 -ISSN-L2644-4046|Vol.6. Núm. 2, Junio –Noviembre 2018AbstractThe quality of water for human consumption was evaluated in seven house developments in the districts of David and Dolega, to contribute to food safety. The study type was descriptive and it was carried out between the years 2016-2018. Chemical, physical and microbiological parameters were evaluated, following standardized analysis techniques. The results show that in general, all the parameters studied were within the permissible values in the Technical Regulation DGNTI-COPANIT 23-395-99(as per Acronym in Spanish),except residual chlorine, this indicates that it is necessary to guarantee the application and monitoring of chlorine in the storage tank. The Panamanian standard establishes a maximum level of 1,5 mg/L and a minimum residual of 0,8 mg/L in the water. No presence of total coliforms was reported in six of the seven house developments evaluated