Impact of PM 10 and meteorological factors on the incidence of hand, foot, and mouth disease in female children in Ningbo, China: a spatiotemporal and time-series study

Abstract

Hand, foot, and mouth disease (HFMD) is a viral illness that is considered a critical public health challenge worldwide. Previous studies have demonstrated that meteorological parameters are significantly related to the incidence of HFMD in children; however, few studies have focused only on female children. This study quantified the associations of HFMD incidence with meteorological parameters and PM₁₀ (particulate matter with an aerodynamic diameter of 10 μm) among female children. Data were collected on daily HFMD cases, meteorological variables, and PM₁₀ levels in Ningbo, China, from January 2012 to December 2016. Data were assessed using a distributed lag nonlinear model (DLNM) with Poisson distribution. A total of 59,809 female children aged 0−15 years with HFMD were enrolled. The results showed that highest relative risk (RR) of HFMD for temperature was 3 °C and the lag effect was 3 days. The highest RR for PM₁₀ was 80 mg/m³ and the lag effect was 5 days. Spatial analysis showed that female HFMD incidence was mainly concentrated in the suburban of Ningbo city indicating that female children in this area should be more paid attention on avoiding this disease outbreak. Our findings suggest that HFMD prevention strategies should focus more attention on local meteorological parameters.

Modelling local uncertainty in relations between birth weight and air quality within an urban area: combining geographically weighted regression with geostatistical simulation

Abstract

In this study, we combine known methods to present a new approach to assess local distributions of estimated parameters measuring associations between air quality and birth weight in the urban area of Sines (Portugal). To model exposure and capture short-distance variations in air quality, we use a Regression Kriging estimator combining air quality point data with land use auxiliary data. To assess uncertainty of exposure, the Kriging estimator is incorporated in a sequential Gaussian simulation algorithm (sGs) providing a set of simulated exposure maps with similar spatial structural dependence and statistical properties of observed data. Following the completion of the simulation runs, we fit a geographically weighted generalized linear model (GWGLM) for each mother's place of residence, using observed health data and simulated exposure data, and repeat this procedure for each simulated map. Once the fit of GWGLM with all exposure maps is finished, we take the distribution of local estimated parameters measuring associations between exposure and birth weight, thus providing a measure of uncertainty in the local estimates. Results reveal that the distribution of local parameters did not vary substantially. Combining both methods (GWGLM and sGs), however, we are able to incorporate local uncertainty on the estimated associations providing an additional tool for analysis of the impacts of place in health.

Phytoremediation of Mn-contaminated paddy soil by two hyperaccumulators ( Phytolacca americana and Polygonum hydropiper ) aided with citric acid

Abstract

The purpose of this study was to investigate the phytoremediation potential of two hyperaccumulator plants, Phytolacca americana L. and Polygonum hydropiper L., on manganese-contaminated paddy soils. The biomass growth, Mn concentrations in plant tissues, and potential Mn removal efficiency from soils of these two plants were studied with citric acid, and the mechanisms of citric acid on these two plants were analyzed by examining the root activity, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in leaves, as well as the concentrations of O₂·⁻ and H₂O₂ in leaves. The results showed that the biomass of these two plants were both promoted under low level of citric acid (3 mmol kg⁻¹). The concentration of Mn in the plants and the amount of Mn removed from the soil by the plants through harvesting were enhanced at low and intermediate (10 mmol kg⁻¹) citric acid application levels. The results also showed that root activity was enhanced at the low citric acid level and significantly inhibited under the intermediate and high levels (15 mmol kg⁻¹), which indicates the facilitative function of the low level of citric acid and the inhibitive function of the high level of citric acid application on plant biomass growth. Under the low and intermediate levels of citric acid application, O₂·⁻ in the plant leaves increased sharply, and the SOD, POD, and CAT activities also increased sharply, which made the level of H₂O₂ very similar to that of the control, ensuring the health of the plants. At the high level of citric acid application, however, the O₂·⁻ continued to rise sharply, while the activity of the three antioxidant enzymes declined sharply, causing the concentration of hydrogen peroxide to be much higher than that in the control, thus endangering the plants. The present study shows the potential of P. hydropiper for use in the phytoremediation of soil contaminated with a relatively low level of manganese.

Placa anular pigmentada submentoniana

Publication date: Available online 30 June 2018
Source:Actas Dermo-Sifiliográficas
Author(s): F.J. Navarro-Triviño, M.J. Naranjo-Díaz, R. Ruiz-Villaverde

Síndrome de Stewart-Bluefarb: caso clínico y revisión de la literatura

Publication date: Available online 30 June 2018
Source:Actas Dermo-Sifiliográficas
Author(s): V.E. García Blanco, E. Dóiz Artázcoz, M.C. Galera Martínez, M. Rodríguez Piñero

Utilidad de la microscopía confocal de reflectancia para el diagnóstico in vivo de los sebomatricomas

Publication date: Available online 30 June 2018
Source:Actas Dermo-Sifiliográficas
Author(s): S. Burillo-Martínez, R. Gamo, F. Pinedo, J.L. López-Estebaranz

Medición del impacto psicológico en pacientes con psoriasis en tratamiento sistémico

Publication date: Available online 30 June 2018
Source:Actas Dermo-Sifiliográficas
Author(s): M.B. Madrid Álvarez, G. Carretero Hernández, A. González Quesada, J.M. González Martín
Antecedentes y objetivosEl impacto negativo que la psoriasis tiene en la calidad de vida del paciente puede ser tan importante como sus consecuencias físicas. Podríamos suponer que el blanqueamiento de la enfermedad conllevaría también una mejoría de su impacto psicosocial. El presente estudio valora el estado psicológico de los pacientes con psoriasis controlados con tratamiento sistémico en una Unidad de Psoriasis, especialmente en aquellos con una afectación leve o nula de la enfermedad.MétodosEstudio epidemiológico observacional y trasversal, sin intervención, con dos cohortes (casos y controles). Los pacientes autocompletaron datos demográficos y 4 cuestionarios (Cuestionario de autoestima de Rosenberg, Skindex-29, HADS y COPE-28) en una única visita.ResultadosSe reclutaron 111 pacientes diagnosticados de psoriasis y 109 pacientes control. En autoestima, el promedio y la desviación estándar (DE) del grupo de psoriasis fue de 33,5 (4,8) y de 33,3 (6,7) para el grupo control, sin diferencias significativas. En el Skindex-29, la puntuación media del grupo de pacientes con psoriasis fue casi 3 veces mayor que la media del grupo control (30 vs. 11). Se encontraron diferencias significativas en las puntuaciones del HADS de ambos grupos (12,7 vs. 9,0; p<0,001). Las puntuaciones promedio del HADS-A fueron de 8,0 (4,78) en el grupo de psoriasis frente a 5,7 (3,8) en el grupo control (p<0,001), mientras que las del HADS-D fueron de 4,7 (3,9) frente a 3,2 (3,1) (p<0,004), respectivamente.ConclusionesLos resultados obtenidos indican que es necesario medir el estado psicológico de nuestros pacientes con psoriasis, pues incluso con un control casi total de la enfermedad la afectación psicológica permanece.Background and objectivesThe negative impact of psoriasis on patient quality of life can be as important as the physical consequences of the disease. We could assume that clearance of the disease would also lead to an improvement in its psychosocial impact. The present study assesses the psychological state of patients with psoriasis receiving systemic treatment in a psoriasis unit, especially those with mild or no disease involvement.MethodsWe performed a cross-sectional, observational, noninterventional epidemiological study of 2 cohorts (cases and controls). The patients self-completed demographic data and 4 questionnaires (Rosenberg Self-Esteem Scale, Skindex-29, HADS, and COPE-28 questionnaire) at a single visit.ResultsWe recruited 111 patients diagnosed with psoriasis and 109 control patients. In self-esteem, the mean and standard deviation (SD) score was 33.5 (4.8) for the psoriasis group and 33.3 (6.7) for the control group, with no significant differences. In the Skindex-29, the mean score for the psoriasis group was almost 3 times higher than that of the control group (30 vs. 11). Significant differences were found in the HADS scores of both groups (12.7 vs. 9.0, P<.001). The mean HADS-A scores were 8.0 (4.78) for the psoriasis group compared with 5.7 (3.8) for the control group (P<.001). In the case of HADS-D, the scores were 4.7 (3.9) compared with 3.2 (3.1) (P<.004), respectively.ConclusionsOur findings indicate that it is necessary to assess the psychological state of patients with psoriasis, because psychological effects persist even in cases where the disease is almost totally controlled.

Graphical abstract

Tumoración frontal que aumenta de tamaño con maniobra de Valsalva

Publication date: Available online 30 June 2018
Source:Actas Dermo-Sifiliográficas
Author(s): A. Catalán Griffiths, F. Alfagueme Roldán, I. Salgüero Fernández, M.G. Ragusa

Lesiones de rascado… sin rascado

Publication date: Available online 30 June 2018
Source:Actas Dermo-Sifiliográficas
Author(s): J.L. Ramírez-Bellver, A. Alegre-Sánchez

Silicon improves salt tolerance of Glycyrrhiza uralensis Fisch. by ameliorating osmotic and oxidative stresses and improving phytohormonal balance

Abstract

Si has a beneficial effect on improving plant tolerance to salt stress. Nevertheless, the mechanisms of Si in mediating the stress responses are still poorly understood. Glycyrrhiza uralensis Fisch. (G. uralensis), a well-known medicinal plant, possesses vast therapeutic potentials. In the present study, a pot experiment was conducted to investigate the long-term effects of Si on growth and physiobiochemical characteristics in 2-year-old G. uralensis subjected to different levels of salinity. Si markedly affected G. uralensis growth in a salt concentration-dependent manner and had no effect on G. uralensis growth under 6 g/kg NaCl. However, it partly reversed the reduction effect induced by 9 g/kg NaCl. In addition, Si significantly increased the contents of soluble sugar and protein but deceased proline content and thus increased water relations; Si markedly increased the activities of SOD, peroxidase, and CAT and further resulted in decreased MDA content and membrane permeability. Moreover, Si altered the levels of phytohormones and their balances. With correlation analysis and principal component analysis (PCA), root biomass had a significant negative correlation with MDA and membrane permeability while a positive correlation with indole-3-acetic acid and GA₃. The PCA partitioned the total variance into three PCs contributing maximum (88.234%) to the total diversity among the salt stress with or without Si due to the study of various traits. In conclusion, Si exerts a beneficial property on salt-induced harmful effects in G. uralensis by relieving osmotic stress, improving water relations, and alleviating oxidative stress; thus, altering the levels and balance of phytohormones results in improved growth of salt-stressed G. uralensis.

Ecotoxicological evaluation of electrochemical oxidation for the treatment of sanitary landfill leachates

Abstract

In this study, the efficiency of electrochemical oxidation to treat a sanitary landfill leachate was evaluated by the reduction in physico-chemical parameters and in ecotoxicity. The acute toxicity of the sanitary landfill leachates, before and after treatment, was assessed with the model organism Daphnia magna. Electrochemical oxidation treatment was effective in the removal of organic load and ammonium nitrogen and in the reduction of metal ions concentrations. Furthermore, a reduction of 2.5-fold in the acute toxicity towards D. magna after 36 h of treatment was noticed. Nevertheless, the toxicity of the treated leachate is still very high, and further treatments are necessary in order to obtain a non-toxic effluent to this aquatic organism. Toxicity results were also compared with others described in the literature for different leachate treatments and test organisms.

The spatial distribution of phosphorus and their correlations in surface sediments and pore water in Lake Chaohu, China

Abstract

The study presents the spatial distribution of different forms of phosphorus in the sediments in Lake Chaohu, a large eutrophic Chinese lake, and their correlation with phosphorus content in pore water. The sediment and pore water samples were taken from 19 sampling sites. A sequential extraction was used to determine the contents of different forms of phosphorus in the sediments. The compositions and spatial distribution of different forms of phosphorus in the sediments and their correlation with orthophosphate and total phosphorus content in the pore water were studied. The following results were obtained: (1) the mean content of total phosphorus was 474.7 ± 20.5 mg/kg, with 390.8 ± 82.4 mg/kg for the eastern lake (N = 5), 469.0 ± 53.9 mg/kg for the western lake (N = 5), and 524.5 ± 185.3 mg/kg for rivers (N = 9); (2) the order of the proportions of the different forms of phosphorus was occluded phosphorus (Oc-P, 52.4%) > debris phosphorus (De-P, 14.2%) > auto-calcium-bound phosphorus (ACa-P, 13.5%) > aluminum-bound phosphorus (Al-P, 9.8%) > organic phosphorus (Or-P, 6.8%) > exchangeable phosphorus (Ex-P, 2.1%) > iron-bound phosphorus (Fe-P, 1.3%); (3) Ex-P, Al-P, and Fe-P had significantly positive correlations with orthophosphate and total phosphorus content in pore water, which showed that these forms of phosphorus were released more easily and had an indirect impact on lake eutrophication.

Association between prenatal nickel exposure and preterm low birth weight: possible effect of selenium

Abstract

There is a proposed link between prenatal nickel (Ni) exposure and preterm low birth weight (PLBW); however, this association remains unclear. Selenium (Se) may modify this relationship by protecting against Ni toxicity. Concentrations of Ni and Se were measured in urine samples collected from 408 pregnant women (102 PLBW cases and 306 matched controls) in China. Conditional logistic regression was utilized to explore the association between Ni levels and PLBW, as well as the effect modification by Se on this association. A significant association was observed between higher maternal urinary Ni levels and risk of PLBW [adjusted odds ratio (OR) = 2.80 (95% confidence interval (CI): 1.44, 5.44) for the highest tertile], and this association was more apparent among female infants than that among male infants. Further analyses showed that mothers with high urinary Ni and low urinary Se levels had a significantly increased risk for PLBW [adjusted OR = 2.87 (95% CI: 1.09, 7.56)] compared with the mothers with low urinary Ni and high urinary Se levels. Our study indicates that prenatal exposure to Ni was a risk factor for PLBW. Se might provide protection against the toxicity of Ni.

Impact of waste-derived organic and inorganic amendments on the mobility and bioavailability of arsenic and cadmium in alkaline and acid soils

Abstract

In agriculture, more and more frequently waste-derived amendments are applied to soil to improve physical and chemical properties. Nevertheless, in soils polluted by potentially toxic metal(loid)s, this agricultural practice may significantly affect the mobility and bioavailability of pollutants modifying the risks for biota and human health. This work was aimed to assess the influence of poultry manure, biochar and coal fly ash on the mobility and bioavailability of As and Cd spiked in two Australian soils with different pH and texture: Mount Gambier (MGB)-alkaline sandy clay loam and Kapuda (KPD)-acid loamy sand. After 4 weeks of incubation from spiking and another 4 weeks from amendment addition, the soils were analysed for pH and amounts of As and Cd in pore-water and following 1 M NH₄NO₃ extraction. Bioavailable amounts were assessed by plant uptake, using Zea mays L. as test crop. In the alkaline MGB soil, the availability of Cd was reduced, while that of As increased. An opposite behaviour was observed in the acid KPD soil. All amendments, when added to KPD soil, increased pH and consequently reduced the mobility of Cd and increased the mobility of As. In MGB, the amendment addition had an effect only on As mobility and bioavailability, which increased likely as a result of the increased competition for adsorption with DOC released by organic compounds. These trends were confirmed by the amounts of Cd and As uptaken by maize plants.

Varying concentrations of soil chromium (VI) for the exploration of tolerance thresholds and phytoremediation potential of the oregano ( Origanum vulgare )

Abstract

Varying concentrations of soil Cr(VI) were used in order to explore the tolerance thresholds and phytoremediation potential of Greek oregano (Origanum vulgare), in a pot experiment conducted outdoors. Oregano exhibited a rather exceptional capacity to bioaccumulate Cr in both the aerial part (up to 1200 mg of total Cr kg⁻¹ DM) and the root—reaching 4300 mg kg⁻¹ DM when grown in soil [Cr(VI)] of 150–200 mg kg⁻¹. Plant responses indicated that there was a threshold set at 100 mg Cr(VI) kg⁻¹ in the soil, above which the following results were recorded: (i) a restriction of Cr translocation from below- to above-ground plant part, (ii) a raise of the soil-to-root Cr transfer, and (iii) the Cr(III) evolution from the reduction of Cr(VI) was significantly decelerated in the root and accelerated in the aerial part. Soil [Cr] that surpassed this threshold challenged plant tolerance, resulting in a dose-dependent reduction of growth and antioxidant phenolics pool. Nonetheless, the significant Cr uptake capacity at plant level accounted for the considerably short remediation time (i.e., 29 years at soil [Cr(VI)] of 150 mg kg⁻¹) calculated according to these results. The overall performance of oregano indicated that phytoremediation would be feasible at sites with Cr contamination levels ranging within the above-defined thresholds.

The carotenoid Bixin found to exhibit the highest measured carotenoid oxidation potential to date consistent with its practical protective use in cosmetics, drugs and food

Publication date: Available online 30 June 2018
Source:Journal of Photochemistry and Photobiology B: Biology
Author(s): Sefadzi Tay-Agbozo, Shane Street, Lowell Kispert
The electrochemical oxidation potentials of cis bixin correspond to the production of the carotenoid radical cation, Car⁺ and dication Car⁺⁺. The oxidation is a two-electron process with oxidation potentials at ~0.94 and ~1.14 V vs SCE (reference to ferrocene at 0.528 V) in THF. These potentials are higher than that of symmetrical canthaxanthin at 0.775 V and 0.972 V and for β-carotene at 0.634 V and 0.605 V respectively. The second oxidation potential for canthaxanthin is higher by 0.20 V than the first. Similar difference is observed for bixin. In contrast, the second oxidation potential for β-carotene is lower by 30 mV than that of the first. Reduction potentials were found to occur at ~−0.69 and ~−1.22 V vs SCE. The lifetime of the radical cation of cis bixin, Car⁺, is short and decays rapidly at ambient temperature. The suggested scavenging ability of cis bixin towards reactive oxidative oxygen species is estimated to be 44. On the other hand, that of β-carotene, symmetrical canthaxanthin and the dicyano substituted carotenoid which exhibit oxidation potentials of 0.634 V, 0.775 V and 0.833 V vs SCE were measured to be 0.64, 1.96 and 23.60 respectively. The non-reversible electrochemical measurements suggest the tendency for bixin to react with trace amounts of reactive oxygen species (OH, O2⁻, OOH).

Graphical abstract

Photobiomodulation improved stereological parameters and sperm analysis factors in streptozotocin-induced type 1 diabetes mellitus

Publication date: Available online 30 June 2018
Source:Journal of Photochemistry and Photobiology B: Biology
Author(s): Sara Dadras, Mohammad-Amin Abdollahifar, Hamid Nazarian, Seyed Kamran Ghoreishi, Somyeh Fallahnezhad, Parvaneh Naserzadeh, Vahid Jajarmi, Sufan Chien, Mohammad Bayat
The aim of this study was to evaluate the effect of photobiomodulation (PBM) on testicular tissues and fresh sperm analysis factors in streptozotocin (STZ)-induced type one diabetes mellitus (T1DM) mice.T1DM was induced in 15 male Syrian mice by injection of 200 mg/kg STZ. After one month, mice were divided randomly into three groups, harboring 5 mice each: 1, control group; 2, first laser group (890 nm, 80 Hz, 0.03 J/cm²) and 3, second laser group (0.2 J/cm²). Then the mice were euthanized and testicles were dissected for stereological studies, and both epididymis and vas deferens were removed for fresh sperm analysis. Data were analyzed by statistical methods.A significant increase was observed in the Sertoli cell count in both PBM groups, compared to the control group. In addition, the second PBM group shows a significant increase in the Sertoli cell count, compared to the first PBM group. Both PBM groups show significant increase in the Leydig cell count, compared to the control group. There were significant increases of the length in the seminiferous tubules in both PBM groups, compared to the control group. In addition, the second PBM group showed a significant increase of the length in the seminiferous tubules, compared to the first PBM group. The second PBM group showed a significant increase in the sperm count, compared to the control, and first PBM groups. The first PBM group showed a significant increase in sperm count, compared to the control group. The sperm motility and count were significantly increased in the second PBM group, compared to the control and first PBM groups. The sperm motility was significantly increased in the first PBM group, compared to the control group.PBM with 0.2 J/cm² and 0.03 J/cm² energy densities significantly improved the stereological parameters and fresh sperm analysis factors, compared to the control group in STZ-induced T1DM in mice. Moreover, the PBM with 0.02 J/cm² energy density was statistically more effective, compared to the 0.03 J/cm².

Preliminary Analysis of Pulsed Radiofrequency Therapy Combined with Carpal Tunnel Release for Reducing the Pain in Postoperative Period: Early Outcomes

Publication date: Available online 30 June 2018
Source:Journal of Plastic, Reconstructive & Aesthetic Surgery
Author(s): Gokce Yildiran, Osman Akdag, Inci Kara, Mehtap Karamese

The unexpected diversity of microbial communities associated with black corals revealed by high-throughput Illumina sequencing

Abstract

The microbes associated with black corals remain poorly studied. The present study is the first attempt to investigate microbial community structure in the black corals Antipathes ceylonensis and A. dichotoma from the South China Sea by using high-throughput Illumina sequencing. A total of 52 bacterial and 3 archaeal phyla were recovered in this study, suggesting the black corals harboured highly diverse microbial communities. Among the 55 microbial phyla, Proteobacteria, Firmicutes, Bacteroidetes, Chloroflexi, Acidobacteria and Actinobacteria dominated in the two black corals from the South China Sea. Although most of the microbial phyla recovered from the two black corals have been reported in previous studies on coral-associated microbes, eight bacterial phyla including Synergistetes, Thermi, AncK6, GNO2, NKB19, NC10, WWE1 and GAL15, and the archaeal phylum Parvarchaeota are reported for the first time from corals in this study, which expands our knowledge about the diversity of coral-associated microbes. The comparison of microbial communities in the different black coral species indicated that A. ceylonensis harboured few abundant bacterial genera such as Citrobacter and Pseudomonas, whereas a high diversity of rare bacterial genera (<1% abundance), such as Winogradskyella and Rubricoccus, was detected only in A. dichotoma. These results suggested that the microbial community in black corals exhibited species-specific variation.

Transport and metabolic engineering of the cell factory Corynebacterium glutamicum

Abstract

Corynebacterium glutamicum has a long and successful history in the biotechnological production of the amino acids l-glutamate and l-lysine. In the recent years, C. glutamicum has been engineered for the production of a broad catalog of value-added compounds including organic acids, vitamins, terpenoids and proteins. Moreover, this bacterium has been engineered to realize a flexible carbon source concept enabling product formation from various second generation feedstocks without competing uses in human and animal nutrition. In this review, we highlight transport engineering to improve product export and substrate uptake or to avoid loss of intermediates by excretion as well as the application of new metabolic engineering concepts for C. glutamicum strain development including the use of designed synthetic E. coli-C. glutamicum consortia. As examples, pathway extension of l-lysine and l-glutamate biosynthesis to produce derived value-added chemicals is described. The described examples of C. glutamicum strain engineering reflect strategies to cope with the increasing complexity of biotechnological processes that are required for successful applications in the bioeconomy.

Educating in antimicrobial resistance awareness: adaptation of the Small World Initiative program to service-learning

Abstract

The Small World Initiative (SWI) is a consolidated and successful education program rooted in the USA that tackles the antibiotic crisis by a crowdsourcing strategy. Based on active learning, it challenges young students to discover novel bioactive-producing microorganisms form environmental soil samples. Besides its pedagogical efficiency to impart Microbiology contents in academic curricula, SWI promotes vocations on research and development in Experimental Sciences and, at the same time, disseminates the antibiotic awareness guidelines of the World Health Organization (WHO). We have adapted the SWI program to the Spanish academic environment by a pioneering hierarchic strategy based on service-learning that involves two education levels (higher education and high school) with different degrees of responsibility. Along the academic year, 23 SWI teams each consisting of 3–7 undergraduate students led by one faculty member have coordinated off-campus programs in 22 local high schools, involving 597 secondary/high school students as researchers. Post-survey-based evaluation of the program reveals a satisfactory achievement of goals: acquiring scientific abilities and general or personal competencies by university students, as well as promoting academic decisions to inspire vocations for science- and technology-oriented degrees in younger students, and successfully communicating scientific culture in antimicrobial resistance to a young stratum of society.

Insights into the phylogeny of false-branching heterocytous cyanobacteria with the description of Scytonema pachmarhiense sp. nov. isolated from Pachmarhi Biosphere Reserve, India

Abstract

A false branching cyanobacterium (strain 10A1_PS) was isolated from a freshwater body of the Pachmarhi Biosphere Reserve, India and was characterized using the polyphasic approach. The detailed morphological examination indicated that the strain belonged to the complex genus Scytonema as it exhibited typical false branching character whose frequency increased with age of the culture. As the family Scytonemataceae and the genus Scytonema has been shown to be polyphyletic in many studies, we provide deep insights into the phylogenetic complexities within the family Scytonemataceae based on 16S rRNA gene phylogeny along with complete morphological, molecular and phylogenetic characterization of the strain. The 16S rRNA gene phylogenetic tree inferred by Bayesian Inference, Neighbor-Joining and Maximum Parsimony methods showed that the strain clustered within the Scytonema sensu stricto clade. The phylogenetic distance and the positioning of the strain clearly indicated it to be different from other Scytonema species. Further analysis using rbcL phylogeny, folded secondary structures of the 16S-23S ITS, p-distance and percentage pairwise similarity matrix clearly distinguished the strain 10A1_PS from the other closely related species. In accordance with the International Code of Nomenclature of Algae, Fungi and Plants we propose the name of the new species to be Scytonema pachmarhiense.

The influence of sigma factors and ribosomal recognition elements on heterologous expression of cyanobacterial gene clusters in Escherichia coli

Abstract

Cyanobacterial natural products offer new possibilities for drugs and lead compounds but many factors can inhibit the production of sufficient yields for pharmaceutical processes. While Escherichia coli and Streptomyces sp. have been used as heterologous expression hosts to produce cyanobacterial natural products, they have not met with resounding success largely due to their inability to recognize cyanobacterial promoter regions. Recent work has shown that the filamentous freshwater cyanobacterium Anabaena sp. strain PCC 7120 recognizes various cyanobacterial promoter regions and can produce lyngbyatoxin A from the native promoter. Introduction of Anabaena sigma factors into E. coli might allow the native transcriptional machinery to recognize cyanobacterial promoters. Here, all 12 Anabaena sigma factors were expressed in E. coli and subsets were found to initiate transcription from several cyanobacterial promoters based on transcriptional fusions to the chloramphenicol acetyltransferase (CAT) reporter. Expression of individual Anabaena sigma factors in E. coli did not result in lyngbyatoxin A production from its native cyanobacterial gene cluster, possibly hindered by deficiencies in recognition of cyanobacterial ribosomal binding sites by native E. coli translational machinery. This represents an important step toward engineering E. coli into a general heterologous expression host for cyanobacterial biosynthetic gene cluster expression.