702 research outputs found
Highly efficient fullerene and non-fullerene based ternary organic solar cells incorporating a new tetrathiocin-cored semiconductor
A new dual-chain oligothiophene-based organic semiconductor, EH-5T-TTC, is presented. The molecule contains two conjugated chains linked by a fused tetrathiocin core. X-ray crystallography reveals a boat conformation within the 8-membered sulfur heterocycle core and extensive π–π and intermolecular sulfur–sulfur interactions in the bulk, leading to a 2-dimensional structure. This unusual molecule has been studied as a ternary component in organic solar cell blends containing the electron donor PTB7-Th and both fullerene (PC71BM) and non-fullerene acceptors ITIC and EH-IDTBR. By incorporating EH-5T-TTC as a ternary component, the power conversion efficiency of the binary blends containing non-fullerene acceptor increases by 17% (from 7.8% to 9.2%) and by 85% for the binary blend with fullerene acceptor (from 3.3% to 6.3%). Detailed characterisation of the ternary blend systems implies that the ternary small molecule EH-5T-TTC functions differently in polymer:fullerene and polymer:non-fullerene blends and has dual functions of morphology modification and complementary spectral absorption
Tris-ureas as transmembrane anion transporters
Nine tris-urea receptors (L1–L9) have been synthesised and shown to coordinate to a range of anionic guests both by 1H NMR titration techniques and single crystal X-ray structural analysis. The compounds have been shown to be capable of mediating the exchange of chloride and nitrate and also chloride and bicarbonate across POPC or POPC : cholesterol 7 : 3 vesicle bilayer membranes at low transporter loadings. An interesting dependency of anion transport on the nature of the cation is evidence to suggest that a M+/Cl− cotransport process may also contribute to the release of chloride from the vesicles
Proteomic comparisons of opaque and transparent variants of <i>Streptococcus pneumoniae</i> by two dimensional-differential gel electrophoresis
Streptococcus pneumoniae (the pneumococcus) is a human pathogen, accounting for massive global morbidity and mortality. Although asymptomatic colonization of the nasopharynx almost invariably precedes disease, the critical determinants enabling pneumococcal progression from this niche to cause invasive disease are poorly understood. One mechanism proposed to be central to this transition involves opacity phase variation, whereby pneumococci harvested from the nasopharynx are typically transparent, while those simultaneously harvested from the blood are opaque. Here, we used two dimensional-differential gel electrophoresis (2D-DIGE) to compare protein expression profiles of transparent and opaque variants of 3 pneumococcal strains, D39 (serotype 2), WCH43 (serotype 4) and WCH16 (serotype 6A) in vitro. One spot comprising a mixture of capsular polysaccharide biosynthesis protein and other proteins was significantly up-regulated in the opaque phenotype in all 3 strains; other proteins were differentially regulated in a strain-specific manner. We conclude that pneumococcal phase variation is a complex and multifactorial process leading to strain-specific pathogenicity.Melissa H. Chai, Florian Weiland, Richard M. Harvey, Peter Hoffmann, Abiodun D. Ogunniyi, James C. Pato
Imaging features of foreign body granuloma in the lower extremities mimicking a soft tissue neoplasm
Foreign body granuloma is a tissue reaction for retained foreign bodies after skin-penetrating trauma. Detection of retained foreign bodies can be extremely difficult when the patients present with non-specific symptoms such as pain and/or swelling without recognizing a previous trauma. We report three patients of foreign body granulomas in the lower extremities with emphasis placed on their unique clinical and radiological features. The involved sites were the foot, posterior thigh, and posterior lower leg, with wooden splinters in two patients and a fragment of tile in one. Plain radiographs could not reveal the existence of foreign bodies. Magnetic resonance imaging (MRI) showed foreign bodies as low intensities on both T1- and T2-weighted images in two patients, and the surrounding reactive lesion as low to iso intensities on T1- and high intensities on T2-weighted images in all the patients. The peripheral areas of the lesion were strongly enhanced after gadolinium injection. Ultrasound sonography could clearly visualize a foreign body as an echogenic area with posterior acoustic shadowing in one patient. The surrounding ring-like reactive lesion is easily mistaken for a soft tissue neoplasm when foreign bodies are not identified. The key to arriving at the correct diagnosis is to clarify the previous trauma and to identify foreign bodies with low signal intensities on both T1- and T2-weighted images and/or the characteristic ring-like enhancement on MRI. It is also necessary to rule out a foreign body granuloma whenever we see patients with a soft tissue tumor in the extremities, irrespective of their previous trauma history
Verified and potential pathogens of predatory mites (Acari: Phytoseiidae)
Several species of phytoseiid mites (Acari: Phytoseiidae), including species of the genera Amblyseius, Galendromus, Metaseiulus, Neoseiulus, Phytoseiulus and Typhlodromus, are currently reared for biological control of various crop pests and/or as model organisms for the study of predator¿prey interactions. Pathogen-free phytoseiid mites are important to obtain high efficacy in biological pest control and to get reliable data in mite research, as pathogens may affect the performance of their host or alter their reproduction and behaviour. Potential and verified pathogens have been reported for phytoseiid mites during the past 25 years. The present review provides an overview, including potential pathogens with unknown host effects (17 reports), endosymbiotic Wolbachia (seven reports), other bacteria (including Cardinium and Spiroplasma) (four reports), cases of unidentified diseases (three reports) and cases of verified pathogens (six reports). From the latter group four reports refer to Microsporidia, one to a fungus and one to a bacterium. Only five entities have been studied in detail, including Wolbachia infecting seven predatory mite species, other endosymbiotic bacteria infecting Metaseiulus (Galendromus, Typhlodromus) occidentalis (Nesbitt), the bacterium Acaricomes phytoseiuli infecting Phytoseiulus persimilis Athias-Henriot, the microsporidium Microsporidium phytoseiuli infecting P. persimilis and the microsporidium Oligosproridium occidentalis infecting M. occidentalis. In four cases (Wolbachia, A. phytoseiuli, M. phytoseiuli and O. occidentalis) an infection may be connected with fitness costs of the host. Moreover, infection is not always readily visible as no obvious gross symptoms are present. Monitoring of these entities on a routine and continuous basis should therefore get more attention, especially in commercial mass-production. Special attention should be paid to field-collected mites before introduction into the laboratory or mass rearing, and to mites that are exchanged among rearing facilities. However, at present general pathogen monitoring is not yet practical as effects of many entities are unknown. More research effort is needed concerning verified and potential pathogens of commercially reared arthropods and those used as model organisms in research
Molecular identification of adenoviruses associated with respiratory infection in Egypt from 2003 to 2010.
BACKGROUND: Human adenoviruses of species B, C, and E (HAdV-B, -C, -E) are frequent causative agents of acute respiratory infections worldwide. As part of a surveillance program aimed at identifying the etiology of influenza-like illness (ILI) in Egypt, we characterized 105 adenovirus isolates from clinical samples collected between 2003 and 2010. METHODS: Identification of the isolates as HAdV was accomplished by an immunofluorescence assay (IFA) and confirmed by a set of species and type specific polymerase chain reactions (PCR). RESULTS: Of the 105 isolates, 42% were identified as belonging to HAdV-B, 60% as HAdV-C, and 1% as HAdV-E. We identified a total of six co-infections by PCR, of which five were HAdV-B/HAdV-C co-infections, and one was a co-infection of two HAdV-C types: HAdV-5/HAdV-6. Molecular typing by PCR enabled the identification of eight genotypes of human adenoviruses; HAdV-3 (n = 22), HAdV-7 (n = 14), HAdV-11 (n = 8), HAdV-1 (n = 22), HAdV-2 (20), HAdV-5 (n = 15), HAdV-6 (n = 3) and HAdV-4 (n = 1). The most abundant species in the characterized collection of isolates was HAdV-C, which is concordant with existing data for worldwide epidemiology of HAdV respiratory infections. CONCLUSIONS: We identified three species, HAdV-B, -C and -E, among patients with ILI over the course of 7 years in Egypt, with at least eight diverse types circulating
A transcription factor contributes to pathogenesis and virulence in streptococcus pneumoniae
To date, the role of transcription factors (TFs) in the progression of disease for many pathogens is yet to be studied in detail. This is probably due to transient, and generally low expression levels of TFs, which are the central components controlling the expression of many genes during the course of infection. However, a small change in the expression or specificity of a TF can radically alter gene expression. In this study, we combined a number of quality-based selection strategies including structural prediction of modulated genes, gene ontology and network analysis, to predict the regulatory mechanisms underlying pathogenesis of Streptococcus pneumoniae (the pneumococcus). We have identified two TFs (SP_0676 and SP_0927 [SmrC]) that might control tissue-specific gene expression during pneumococcal translocation from the nasopharynx to lungs, to blood and then to brain of mice. Targeted mutagenesis and mouse models of infection confirmed the role of SP_0927 in pathogenesis and virulence, and suggests that SP_0676 might be essential to pneumococcal viability. These findings provide fundamental new insights into virulence gene expression and regulation during pathogenesis.Layla K. Mahdi, Esmaeil Ebrahimie, David L. Adelson, James C. Paton, Abiodun D. Ogunniy
Efficacy of Single-Dose and Triple-Dose Albendazole and Mebendazole against Soil-Transmitted Helminths and Taenia spp.: A Randomized Controlled Trial
BACKGROUND: The control of soil-transmitted helminth (STH) infections currently relies on the large-scale administration of single-dose oral albendazole or mebendazole. However, these treatment regimens have limited efficacy against hookworm and Trichuris trichiura in terms of cure rates (CR), whereas fecal egg reduction rates (ERR) are generally high for all common STH species. We compared the efficacy of single-dose versus triple-dose treatment against hookworm and other STHs in a community-based randomized controlled trial in the People's Republic of China. METHODOLOGY/PRINCIPAL FINDINGS: The hookworm CR and fecal ERR were assessed in 314 individuals aged </=5 years who submitted two stool samples before and 3-4 weeks after administration of single-dose oral albendazole (400 mg) or mebendazole (500 mg) or triple-dose albendazole (3x400 mg over 3 consecutive days) or mebendazole (3x500 mg over 3 consecutive days). Efficacy against T. trichiura, Ascaris lumbricoides, and Taenia spp. was also assessed. ALBENDAZOLE CURED SIGNIFICANTLY MORE HOOKWORM INFECTIONS THAN MEBENDAZOLE IN BOTH TREATMENT REGIMENS (SINGLE DOSE: respective CRs 69% (95% confidence interval [CI]: 55-81%) and 29% (95% CI: 20-45%); triple dose: respective CRs 92% (95% CI: 81-98%) and 54% (95% CI: 46-71%)). ERRs followed the same pattern (single dose: 97% versus 84%; triple dose: 99.7% versus 96%). Triple-dose regimens outperformed single doses against T. trichiura; three doses of mebendazole - the most efficacious treatment tested - cured 71% (95% CI: 57-82%). Both single and triple doses of either drug were highly efficacious against A. lumbricoides (CR: 93-97%; ERR: all <99.9%). Triple dose regimens cured all Taenia spp. infections, whereas single dose applications cured only half of them. CONCLUSIONS/SIGNIFICANCE: Single-dose oral albendazole is more efficacious against hookworm than mebendazole. To achieve high CRs against both hookworm and T. trichiura, triple-dose regimens are warranted. CONCLUSIONS/SIGNIFICANCE: Single-dose oral albendazole is more efficacious against hookworm than mebendazole. To achieve high CRs against both hookworm and T. trichiura, triple-dose regimens are warranted. TRIAL REGISTRATION: www.controlled-trials.comISRCTN4737502
Lymphatic Filariasis Control in Tanzania: Effect of Repeated Mass Drug Administration with Ivermectin and Albendazole on Infection and Transmission
Lymphatic filariasis (LF) is a disabling mosquito borne parasitic disease and one of the major neglected tropical diseases. In most countries of Sub-Saharan Africa the control of LF is based on yearly mass drug administration (MDA) with a combination of ivermectin and albendazole, in order to interrupt transmission. We monitored the effect of 3 repeated MDAs with this drug combination, as implemented by the Tanzanian National Lymphatic Filariasis Elimination Programme, on human infection and mosquito transmission during a five-year period (one pre-intervention and four post-intervention years) in a highly endemic community in north-eastern Tanzania. After start of intervention, human infection with the blood-stage larva of the parasite (microfilaria) initially decreased rapidly, leading to considerable reduction in transmission. The effects thereafter levelled off and transmission still occurred at low level after the third MDA. The MDAs had limited effect on molecular markers of adult worm burden (circulating filarial antigens) and transmission exposure (antibodies to Bm14 antigen) in the human population. The study highlights the importance of monitoring and regular evaluation in order to make evidence based programme adjustments, and it points to a need for further assessment of the long-term effect of repeated ivermectin/albendazole MDAs (including the importance of application intervals and treatment coverage), in order to optimize efforts to control LF in sub-Saharan Africa
Factors influencing citrus fruit scarring caused by Pezothrips kellyanus
[EN] Kelly s citrus thrips (KCT) Pezothrips kellyanus
(Bagnall) (Thysanoptera: Thripidae) is a recently recorded
cosmopolitan citrus pest, causing fruit scarring that results in
downgrading of fruit. Due to the detrimental effects caused
on fruits by KCT, we wanted to study some of the factors
influencing fruit scarring. Specifically, the objectives were:
(1) to determine the fruit development stage when citrus
fruits are damaged by KCT and the population structure of
KCT during this period, (2) to study the influence of temperature
on intensity of damage, and finally, (3) to identify
alternative host plants. KCT populations on flowers and
fruitlets and alternate plant hosts were sampled in four citrus
orchards from 2008 to 2010. The percentage of damaged
fruits was also recorded. The exotic vine Araujia sericifera
(Apocynaceae) was recorded as a new host for KCT. Thrips
scarring started to increase at 350 650 degree-days (DD)
above 10.2 C, coinciding with a peak abundance of the
second instar larval stages over all 3 years of the study. The
maximum percentage of larval stages of KCT was observed
in the 3 years at about 500 DD, a period which corresponds to
the end of May or early June. Variation in the severity of fruit
scarring appeared to be related to air temperature. Temperature
likely affects the synchronisation between the peak in
abundance of KCT larvae, and the period when fruitlets are
susceptible to thrips damage. Temperature can also influence
the survival and development of KCT populations in citrus
and other host plants in the citrus agro-ecosystem.The authors thank Alejandro Tena for his valuable suggestions and two anonymous referees for their careful review and helpful comments. We also extend our thanks to the owners of the commercial orchards for giving us permission to use their citrus orchards. The first author was awarded an FPI fellowship from the Polytechnic University of Valencia to obtain her PhD degree.Navarro Campos, C.; Pekas, A.; Aguilar Martí, MA.; Garcia Marí, F. (2013). Factors influencing citrus fruit scarring caused by Pezothrips kellyanus. Journal of Pest Science. (86):459-467. doi:10.1007/s10340-013-0489-7S45946786Baker GJ (2006) Kelly citrus thrips management. Fact sheet. Government of South Australia, primary industries and resources SA. http://www.sardi.sa.gov.au/__data/assets/pdf_file/0010/44875/kctfact_sheet.pdf . Accessed 16 July 2012Baker GJ, Jackman DJ, Keller M, MacGregor A, Purvis S (2002) Development of an integrated pest management system for thrips in Citrus. HAL Final Report CT97007. http://www.sardi.sa.gov.au/pestsdiseases/horticulture/horticultural_pests/kelly_citrus_thrips/research_report_1997-2000 . Accessed 16 July 2012Bedford ECG (1998) Thrips, wind and other blemishes. Citrus pests in the Republic of South Africa. In: Bedford ECG, van den Berg MA, de Villiers EA (eds) ARC-Institute for tropical and subtropical crops, Nelspruit, South Africa, pp 170–183Blank RH, Gill GSC (1997) Thrips (Thysanoptera: Terebrantia) on flowers and fruit of citrus in New Zealand. N Z J Crop Hortic Sci 25:319–332Chellemi D, Funderburk F, Hall D (1994) Seasonal abundance of flower-inhabiting Frankliniella species (Thysanoptera: Thripidae) on wild plant species. Environ Entomol 23:337–342Conti F, Tuminelli R, Amico C, Fisicaro R, Frittitta C, Perrotta G, Marullo R (2001) Monitoring Pezothrips kellyanus on citrus in eastern Sicily, Thrips and tospoviruses. In: Proceedings of the 7th international symposium on Thysanoptera, Reggio Calabria, 1–8 July 2001, Italy, pp 207–210Costa L, Mateus C, zurStrassen R, Franco JC (2006) Thrips (Thysanoptera) associated to lemon orchards in the Oeste region of Portugal. IOBC/WPRS Bull 29:285–291European Plant Protection Organisation Reporting Service [EPPO] (2006) Pezothrips kellyanus. http://www.eppo.org/QUARANTINE/Pest_Risk_Analysis/PRAdocs_insects/06-12760%20DS%20PEZTKE.doc. Accessed 18 June 2012European Plant ProtectionOrganisation Reporting Service [EPPO] (2005) Scirtothrips aurantii, Scirtothrips citri, Scirtothrips dorsalis. EPPO Bull 35:353–356Franco JC, Garcia-Marí F, Ramos AP, Besri M (2006) Survey on the situation of citrus pest management in Mediterranean countries. IOBC/WPRS Bull 29:335–346Froud KJ, Stevens PS, Steven D (2001) Survey of alternative host plants for Kelly’s citrus thrips (Pezothrips kellyanus) in citrus growing regions. N Z Plant Prot 54:15–20Gomez-Clemente F (1952) Un tisanóptero causante de daños en las naranjas de algunas zonas de Levante. Boletín de Patología Vegetal y Entomología Agrícola 19:135–146Grout TG, Morse JG, O’Connell NV, Flaherty DL, Goodell PB, Freeman MW, Coviello RL (1986) Citrus thrips (Thysanoptera: Thripidae) phenology and sampling in the San Joaquin Valley. J Econ Entomol 79:1516–1523Horton J (1918) The citrus thrips. US Dep Agric Bull 616:1–42Kirk WDJ (1987) A key to the larvae of some common Australian flower thrips (Insecta: Thysanoptera), with a host-plant survey. Aust J Zool 35:173–185Lacasa A, Llorens JM, Sánchez JA (1996) Un Scirtothrips (Thysanoptera: Thripidae) causa daños en los cítricos en España. Bol San Veg Plagas 22:79–95Lewis HC (1935) Factors influencing citrus thrips damage. J Econ Entomol 28:1011–1015Lewis T (1997) Distribution, abundance and population dynamics. In: Lewis T (ed) Thrips as crop pests. CAB International, Wallingford, pp 217–258Lovatt C, Streeter S, Minter T, O’connell N, Flaherty D, Freeman M, Goodell P (1984) Phenology of flowering in Citrus sinensis (L.) Osbeck, cv. Washington navel orange. Proc Int Soc Citric 1:186–190Marullo R (1998) Pezothrips kellyanus, un nuovo tripide parassita delle colture meridionali. Informatore Fitopatologico 48:72–75Milne JR, Milne M, Walter GH (1997) A key to larval thrips (Thysanoptera) from Granite Belt stonefruit trees and a first description of Pseudanaphothrips achaetus (Bagnall) larvae. Aust J Entomol 36:319–326Mound LA, Jackman DJ (1998) Thrips in the economy and ecology of Australia, In: Zalucki MP, RAI Drew RAI, White GG (eds) Pest Management: future challenges, Proceedings of the sixth Australian applied entomological research conference, University of Queensland, St. Lucia, pp 472–478Mound LA, Marullo R (1996) The thrips of Central and South America (Insecta: Thysanoptera): an introduction. Mem Entomol Int 6:1–487Mound LA, Walker AK (1982) Terebrantia (Insecta: Thysanoptera). Fauna N Z 1:1–113Navarro-Campos C, Marzal C, Aguilar A, GarciaMarí F (2010) Presencia del microlepidóptero Anatrachyntisbadia en cítricos: descripción, comportamiento y daños al fruto. Levante Agrícola 402:270–276Navarro-Campos C, Aguilar A, Garcia-Marí F (2011) Population trend and fruit damage of Pezothrips kellyanus in citrus orchards in Valencia (Spain). IOBC/WPRS Bull 62: 285–292Navarro-Campos C, Aguilar A, Garcia-Marí F (2012) Aggregation pattern, sampling plan and intervention threshold for Pezothrips kellyanus in citrus groves. Entomol Exp Appl 142:130–139Northfield TD, Paini DR, Funderburk JE, Reitz SR (2008) Annual cycles of Frankliniella spp. (Thysanoptera: Thripidae) thrips abundance on North Florida uncultivated reproductive hosts: predicting possible sources of pest outbreaks. Ann Entomol Soc Am 101:769–778Orphanides G (1997) Thrips on citrus. Annual Review for 1997. Agricultural Research Institute, Nicosia, CyprusPerrotta G, Conti F (2008) A threshold hypothesis for an integrated control of thrips infestation on citrus in South-Eastern Sicily. IOBC/WPRS Bull 38:204–209Reitz S, Yu-lin G, Zhong-ren L (2011) Thrips: pests of concern to China and the United States. Agric Sci China 10:867–892Rhodes AA, Morse JG (1989) Scirtothrips citri sampling and damage prediction on California navel oranges. Agric Ecosyst Environ 26:117–129Schellhorn NA, Glatz RV, Wood GM (2010) The risk of exotic and native plants as hosts for four pest thrips (Thysanoptera: Thripinae). Bull Entomol Res 100:501–510Schweizer H, Morse JG (1997) Estimating the level of fruit scarring by citrus thrips from temperature conditions prior to the end of bloom. Crop Prot 16:743–752Smith D, Beattie GAC, Broadley R (eds) (1997) Citrus pests and their natural enemies: integrated pest management in Australia. Information series Q197030. Queensland Department of Primary Industries, BrisbaneStatgraphics (1994) Version 5.1 Plus. Statistical Graphics System by Statistical Graphics Corporation. Manugistics, RockvilleTanigoshi LK, Nishio JY, Moreno DS, Fargerlund J (1980) Effect of temperature on development and survival of Scirtothrips citri on citrus foliage. Ann Entomol Soc Am 73: 378–338Teksam I, Tunç I (2009) An analysis of Thysanoptera associated with citrus flowers in Antalya, Turkey: composition, distribution, abundance and pest status of species. Appl Entomol Zool 44:455–464Varikou K, Tsitsipis JA, Alexandrakis V, Mound LA (2002) Pezothrips kellyanus (Bagnall) (Thysanoptera: Thripidae), a new pest of citrus trees in Crete, In: Proceedings of the VII European congress of entomology, Thessaloniki, Greece, 7–13 Oct 2002, p 33Varikou K, Tsitsipis I, Alexandrakis V, Hoddle M (2009) Effect of temperature on the development and longevity of Pezothrips kellyanus (Thysanoptera: Thripidae). Ann Entomol Soc Am 102:835–841Varikou K, Birouraki A, Tsitsipis I, Sergentani CHR (2012) Effect of temperature on the fecundity of Pezothrips kellyanus (Thysanoptera: Thripidae). Ann Entomol Soc Am 105:60–65Vassiliou VA (2007) Chemical control of Pezothrips kellyanus (Thysanoptera: Thripidae) in citrus plantations in Cyprus. Crop Prot 26:1579–1584Vassiliou VA (2010) Ecology and behavior of Pezothrips kellyanus (Thysanoptera: Thripidae) on Citrus. J Econ Entomol 103:47–53Vierbergen G, Kucharczyk H, Kirk WDJ (2010) A key to the second instar larvae of the Thripidae of the Western Palearctic region. Tijdschr Entomol 153:99–160Webster KW, Cooper P, Mound LA (2006) Studies on Kelly’s citrus thrips, Pezothrips kellyanus (Bagnall) (Thysanoptera: Thripidae): sex attractants, host associations and country of origin. Aust J Entomol 45:67–74Wiesenborn W, Morse JG (1986) Feeding rate of Scirtothripscitri (Moulton) (Thysanoptera: Thripidae) as influenced by life stage and temperature. Environ Entomol 15:763–76
- …