Colonization of dodder, Cuscuta indecora, by 'Candidatus Liberibacter asiaticus' and 'Ca. L. americanus'.

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Hartung, John S; Paul, Cristina; Achor, Diann; Brlansky, R H

2010-08-01

Huanglongbing, or citrus greening, threatens the global citrus industry. The presumptive pathogens, 'Candidatus Liberibacter asiaticus' and 'Ca. L. americanus' can be transferred from citrus to more easily studied experimental hosts by using holoparasitic dodder plants. However, the interaction between 'Candidatus Liberibacter' spp. and the dodder has not been studied. We combined quantitative polymerase chain reaction with electron microscopy to show that only 65% of tendrils of Cuscuta indecora grown on 'Ca. Liberibacter' spp.-infected host plants had detectable levels of the pathogen. Among tendrils that were colonized by Liberibacter in at least one 2 cm segment, most were not colonized in all segments. Furthermore, the estimated population levels of the pathogen present in serial 2 cm segments of dodder tendrils varied widely and without any consistent pattern. Thus, there was generally not a concentration gradient of the pathogen from the source plant towards the recipient and populations of the pathogen were sometimes found in the distal segments of the dodder plant but not in the proximal or middle segments. Populations of the pathogens ranged from 2 x 10(2) to 3.0 x 10(8) cells per 2 cm segment. On a fresh weight basis, populations as high as 1.4 x 10(10) cells per g of tissue were observed demonstrating that 'Ca. Liberibacter' spp. multiplies well in Cuscuta indecora. However, 55% of individual stem segments did not contain detectable levels of the pathogen, consistent with a pattern of nonuniform colonization similar to that observed in the much more anatomically complex citrus tree. Colonization of dodder by the pathogen is also nonuniform at the ultrastructural level, with adjacent phloem vessel elements being completely full of the pathogen or free of the pathogen. We also observed bacteria in the phloem vessels that belonged to two distinct size classes based on the diameters of cross sections of cells. In other sections from the same tendrils we

Diaphorina citri Nymphs Are Resistant to Morphological Changes Induced by "Candidatus Liberibacter asiaticus" in Midgut Epithelial Cells.

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Mann, Marina; Fattah-Hosseini, Somayeh; Ammar, El-Desouky; Stange, Richard; Warrick, EricaRose; Sturgeon, Kasie; Shatters, Robert; Heck, Michelle

2018-04-01

" Candidatus Liberibacter asiaticus" is the causative bacterium associated with citrus greening disease. " Ca Liberibacter asiaticus" is transmitted by Diaphorina citri more efficiently when it is acquired by nymphs rather than adults. Why this occurs is not known. We compared midguts of D. citri insects reared on healthy or " Ca Liberibacter asiaticus"-infected citrus trees using quantitative PCR, confocal microscopy, and mitochondrial superoxide staining for evidence of oxidative stress. Consistent with its classification as propagative, " Ca Liberibacter asiaticus" titers were higher in adults than in nymphs. Our previous work showed that adult D. citri insects have basal levels of karyorrhexis (fragmentation of the nucleus) in midgut epithelial cells, which is increased in severity and frequency in response to " Ca Liberibacter asiaticus." Here, we show that nymphs exhibit lower levels of early-stage karyorrhexis than adults and are refractory to the induction of advanced karyorrhexis by " Ca Liberibacter asiaticus" in the midgut epithelium. MitoSox Red staining showed that guts of infected adults, particularly males, experienced oxidative stress in response to " Ca Liberibacter asiaticus." A positive correlation between the titers of " Ca Liberibacter asiaticus" and the Wolbachia endosymbiont was observed in adult and nymph midguts, suggesting an interplay between these bacteria during development. We hypothesize that the resistance of the nymph midgut to late-stage karyorrhexis through as yet unknown molecular mechanisms benefits " Ca Liberibacter asiaticus" for efficient invasion of midgut epithelial cells, which may be a factor explaining the developmental dependency of " Ca Liberibacter asiaticus" acquisition by the vector.

Transcriptome analysis of citrus sinensis in response to dual infection by Citrius tristeza virus and ’Candidatus liberibacter asiaticus'

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Huanglongbing (HLB) and Tristeza are destructive and globally distributed citrus diseases, and are responsible for the tremendous economic losses to the citrus industries worldwide. HLB is caused by a gram-negative and phloem-limited member of the a-Proteobacteria, Candidatus Liberibacter asiaticus...

A single prophage carrying a CRISPR/cas system in ‘Candidatus Liberibacter asiaticus’ strain A4 from Guangdong, China

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“Candidatus Liberibacter asiaticus” (CLas) is an unculturable a-proteobacterium associated with citrus huanglongbing (HLB, yellow shoot disease), a highly destructive disease that affects citrus production worldwide. HLB was observed in Guangdong Province of China over a hundred years ago and remain...

Horizontal Transmission of "Candidatus Liberibacter solanacearum" by Bactericera cockerelli (Hemiptera: Triozidae) on Convolvulus and Ipomoea (Solanales: Convolvulaceae)

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Torres, Glenda L.; Cooper, W. Rodney; Horton, David R.; Swisher, Kylie D.; Garczynski, Stephen F.; Munyaneza, Joseph E.; Barcenas, Nina M.

2015-01-01

“Candidatus Liberibacter solanacearum” (Proteobacteria) is an important pathogen of solanaceous crops (Solanales: Solanaceae) in North America and New Zealand, and is the putative causal agent of zebra chip disease of potato. This phloem-limited pathogen is transmitted to potato and other solanaceous plants by the potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae). While some plants in the Convolvulaceae (Solanales) are also known hosts for B. cockerelli, previous efforts to detect Liberibacter in Convolvulaceae have been unsuccessful. Moreover, studies to determine whether Liberibacter can be acquired from these plants by B. cockerelli are lacking. The goal of this study was to determine whether horizontal transmission of Liberibacter occurs among potato psyllids on two species of Convolvulaceae, sweet potato (Ipomoea batatas) and field bindweed (Convolvulus arvensis), which grows abundantly in potato growing regions of the United States. Results indicated that uninfected psyllids acquired Liberibacter from both I. batatas and C. arvensis if infected psyllids were present on plants concurrently with the uninfected psyllids. Uninfected psyllids did not acquire Liberibacter from plants if the infected psyllids were removed from the plants before the uninfected psyllids were allowed access. In contrast with previous reports, PCR did detect the presence of Liberibacter DNA in some plants. However, visible amplicons were faint and did not correspond with acquisition of the pathogen by uninfected psyllids. None of the plants exhibited disease symptoms. Results indicate that horizontal transmission of Liberibacter among potato psyllids can occur on Convolvulaceae, and that the association between Liberibacter and Convolvulaceae merits additional attention. PMID:26555359

Diaphorina citri nymphs are resistant to morphological changes induced by “Candidatus Liberibacter asiaticus” in midgut epithelial cells

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“Candidatus Liberibacter asiaticus” is the causative bacterium associated with citrus greening disease. “Ca. L. asiaticus” is transmitted by Diaphorina citri more efficiently when it is acquired by nymphs rather than adults. Why this occurs is not known. We compared midguts of D. citri reared on hea...

Zebra Chip disease and potato biochemistry: Tuber physiological changes in response to ‘Candidatus Liberibacter solanacearum’ infection over time

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Zebra chip disease (ZC), putatively caused by ‘Candidatus Liberibacter solanacearum’ (Lso), is of increasing concern to potato production in Mexico, the United States, and New Zealand. However, little is known about host tuber physiological changes that result in ZC symptom formation. This study exp...

Zinc treatment increases the titre of 'Candidatus Liberibacter asiaticus' in huanglongbing-affected citrus plants while affecting the bacterial microbiomes

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The bacterial microbiomes of citrus plants in response to ‘Candidatus Liberibacter asiaticus’ (Las)-infection and zinc treatments were deciphered by Phylochip-based metagenomics. The results indicated that 5,475 of over 50,000 known Operational Taxonomic Units (OTUs) in 52 phyla were detected in cit...

Zinc treatment increases the titre of ‘Candidatus Liberibacter asiaticus’ in Huanglongbing-affected citrus plants while affecting the bacterial microbiomes

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Huanglongbing (HLB)-affected citrus often display zinc deficiency symptoms. In this study, supplemental zinc was applied to citrus to determine its effect on Candidatus Liberibacter asiaticus (Las) titer, HLB symptoms, and leaf microbiome. HLB-affected citrus were treated with various amounts of zi...

Draft Genome Sequence of a “Candidatus Liberibacter europaeus” Strain Assembled from Broom Psyllids (Arytainilla spartiophila) from New Zealand

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Thompson, Sarah M.; Kalamorz, Falk; David, Charles; Addison, Shea M.; Smith, Grant R.

2018-01-01

ABSTRACT Here, we report the draft genome sequence of “Candidatus Liberibacter europaeus” ASNZ1, assembled from broom psyllids (Arytainilla spartiophila) from New Zealand. The assembly comprises 15 contigs, with a total length of 1.33 Mb and a G+C content of 33.5%. PMID:29773636

Adoption and validation of Ribonucleotide Reductase (RNR)-based real-time assays for detection of HLB ‘Candidatus Liberibacter asiaticus’ (CLas)

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Huanglongbing (HLB), aka Citrus Greening, is a well-known destructive disease that threatens the multi-billion dollar citrus industry in the United States and citrus production in other countries around the world. The presumptive causal agent of HLB, ‘Candidatus Liberibacter asiaticus' (CLas), is of...

Transcriptome analysis of sweet orange trees infected with ‘Candidatus Liberibacter asiaticus’ and two strains of citrus tristeza virus

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Huanglongbing (HLB) and tristeza, are diseases of citrus caused by a member of the a-proteobacteria, ‘Candidatus Liberibacter asiaticus’ (CaLas), and Citrus tristeza virus (CTV) respectively. HLB is a devastating disease, but CTV strains vary from very severe to very mild. Both CaLas and CTV are p...

Solar thermotherapy reduces the titer of ‘Candidatus Liberibacter asiaticus’ while enhancing canopy growth in HLB-affected residential and commercial citrus

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Huanglongbing (HLB), a systemic and destructive disease of citrus, is associated with three species of a-proteobacteria, ‘Candidatus Liberibacter asiaticus’ (Las), ‘Ca. L. africanus’ and ‘Ca. L. americanus’. Previous studies have found distinct variations in temperature sensitivity and tolerance amo...

The transcriptional activator LdtR from 'Candidatus Liberibacter asiaticus' mediates osmotic stress tolerance.

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Fernando A Pagliai

2014-04-01

Full Text Available The causal agent of Huanglongbing disease, 'Candidatus Liberibacter asiaticus', is a non-culturable, gram negative, phloem-limited α-proteobacterium. Current methods to control the spread of this disease are still limited to the removal and destruction of infected trees. In this study, we identified and characterized a regulon from 'Ca. L. asiaticus' involved in cell wall remodeling, that contains a member of the MarR family of transcriptional regulators (ldtR, and a predicted L,D-transpeptidase (ldtP. In Sinorhizobium meliloti, mutation of ldtR resulted in morphological changes (shortened rod-type phenotype and reduced tolerance to osmotic stress. A biochemical approach was taken to identify small molecules that modulate LdtR activity. The LdtR ligands identified by thermal shift assays were validated using DNA binding methods. The biological impact of LdtR inactivation by the small molecules was then examined in Sinorhizobium meliloti and Liberibacter crescens, where a shortened-rod phenotype was induced by growth in presence of the ligands. A new method was also developed to examine the effects of small molecules on the viability of 'Ca. Liberibacter asiaticus', using shoots from HLB-infected orange trees. Decreased expression of ldtRLas and ldtPLas was observed in samples taken from HLB-infected shoots after 6 h of incubation with the LdtR ligands. These results provide strong proof of concept for the use of small molecules that target LdtR, as a potential treatment option for Huanglongbing disease.

Response of sweet orange (Citrus sinensis) to 'Candidatus Liberibacter asiaticus' infection: microscopy and microarray analyses.

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Kim, Jeong-Soon; Sagaram, Uma Shankar; Burns, Jacqueline K; Li, Jian-Liang; Wang, Nian

2009-01-01

Citrus greening or huanglongbing (HLB) is a devastating disease of citrus. HLB is associated with the phloem-limited fastidious prokaryotic alpha-proteobacterium 'Candidatus Liberibacter spp.' In this report, we used sweet orange (Citrus sinensis) leaf tissue infected with 'Ca. Liberibacter asiaticus' and compared this with healthy controls. Investigation of the host response was examined with citrus microarray hybridization based on 33,879 expressed sequence tag sequences from several citrus species and hybrids. The microarray analysis indicated that HLB infection significantly affected expression of 624 genes whose encoded proteins were categorized according to function. The categories included genes associated with sugar metabolism, plant defense, phytohormone, and cell wall metabolism, as well as 14 other gene categories. The anatomical analyses indicated that HLB bacterium infection caused phloem disruption, sucrose accumulation, and plugged sieve pores. The up-regulation of three key starch biosynthetic genes including ADP-glucose pyrophosphorylase, starch synthase, granule-bound starch synthase and starch debranching enzyme likely contributed to accumulation of starch in HLB-affected leaves. The HLB-associated phloem blockage resulted from the plugged sieve pores rather than the HLB bacterial aggregates since 'Ca. Liberibacter asiaticus' does not form aggregate in citrus. The up-regulation of pp2 gene is related to callose deposition to plug the sieve pores in HLB-affected plants.

Influence of photoperiod duration and phloem disruption through scoring on growth, disease symptoms and bacterial titer in citrus graft-inoculated with Candidatus Liberibacter asiaticus

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Plants inoculated with the huanglongbing (HLB)-associated bacterium, Candidatus Liberibacter asiaticus (CLas) are typically monitored for 8-10 months to identify differences in susceptibility between genotypes. A previous report indicated that continuous light accelerated development of HLB symptoms...

Combining 'omics and microscopy to visualize interactions between the Asian citrus psyllid vector and the Huanglongbing pathogen Candidatus Liberibacter asiaticus in the insect gut

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Huanglongbing, or citrus greening disease, is an economically devastating bacterial disease of citrus. It is associated with infection by the gram-negative bacterium Candidatus Liberibacter asiaticus (CLas). CLas is transmitted by Diaphorina citri, the Asian citrus psyllid (ACP). For insect transmis...

Temporal progression of 'Candidatus Liberibacter asiaticus' infection in citrus and acquisition efficiency by Diaphorina citri.

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Coletta-Filho, Helvecio D; Daugherty, Matthew P; Ferreira, Cléderson; Lopes, João R S

2014-04-01

Over the last decade, the plant disease huanglongbing (HLB) has emerged as a primary threat to citrus production worldwide. HLB is associated with infection by phloem-limited bacteria ('Candidatus Liberibacter' spp.) that are transmitted by the Asian citrus psyllid, Diaphorina citri. Transmission efficiency varies with vector-related aspects (e.g., developmental stage and feeding periods) but there is no information on the effects of host-pathogen interactions. Here, acquisition efficiency of 'Candidatus Liberibacter asiaticus' by D. citri was evaluated in relation to temporal progression of infection and pathogen titer in citrus. We graft inoculated sweet orange trees with 'Ca. L. asiaticus'; then, at different times after inoculation, we inspected plants for HLB symptoms, measured bacterial infection levels (i.e., titer or concentration) in plants, and measured acquisition by psyllid adults that were confined on the trees. Plant infection levels increased rapidly over time, saturating at uniformly high levels (≈10(8) copy number of 16S ribosomal DNA/g of plant tissue) near 200 days after inoculation-the same time at which all infected trees first showed disease symptoms. Pathogen acquisition by vectors was positively associated with plant infection level and time since inoculation, with acquisition occurring as early as the first measurement, at 60 days after inoculation. These results suggest that there is ample potential for psyllids to acquire the pathogen from trees during the asymptomatic phase of infection. If so, this could limit the effectiveness of tree rouging as a disease management tool and would likely explain the rapid spread observed for this disease in the field.

DETEKSI MENGGUNAKAN PCR (POLYMERASE CHAIN REACTION CANDIDATUS LIBERIBACTER ASIATICUS, PENYEBAB HUANGLONGBING PADA JERUK SIEM DENGAN BEBERAPA TIPE GEJALA PADA DAUN

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Achmad Himawan, Yohanes Berchmans umardiyono, Susamto Somowiyarjo, Yohanes Andi Trisyono & Andrew Beattie.

2011-11-01

Full Text Available Detection using PCR (Polymerase Chain Reaction Candidatus Liberibacter asiaticus, Huanglongbing causal Organism on Siem Mandarin with different types of symptoms.  Huanglongbing (HLB or Citrus Vein Phloem Degeration (CVPD is one of major diseases on Siem mandarin in Indonesia. HLB is caused by bacteria Candidatus liberibacter asiatus (LAS. The bacteria only live in the phloem cells of host tree and only recently it was reported to be successfully cultured on agar medium. Early detection method of LAS is needed to support healthy Siem mandarin cultivation program. This research was conducted to detect LAS in different types of HLB leaf symptoms based on Polymerase Chain Reaction (PCR method with specific primer forward MHO 353 and reverse MHO 354.  The results suggested that 8 types of HLB leaf symptoms were found on the samples used in this experiment. LAS was detected at 60% on the leaves without any symptom followed by the leaves with completely chlorosis symptom at 66%. The leaves with unevenly yellow showing higher percentage of LAS detection ranged from 80-86%. PCR technique successfully amplified DNA of LAS with the size target of 600 bp.

Reprogramming of a defense signaling pathway in rough lemon and sweet orange is a critical element of the early response to ‘Candidatus Liberibacter asiaticus’

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Huanglongbing (HLB) in citrus infected by Candidatus Liberibacter asiaticus (CLas) has caused tremendous losses to the citrus industry. No resistant genotypes have been identified in citrus species or close relatives. Among citrus varieties, rough lemon (Citrus jambhiri) has been considered tolerant...

A New Diagnostic system for Ultra Sensitive and Specific Detection and Quantitation of “Candidatus Liberibacter asiaticus”, the Bacterium Associated with Citrus Huanglongbing

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In this study, an ultra sensitive and quantitative diagnostic system for “Candidatus Liberibacter asiaticus” was developed. This system adapts a nested PCR and Taq-Man PCR in a single closed tube. The procedure involves two steps of PCR using the species specific outer and inner primer pairs. Differ...

Molecular mechanisms behind the accumulation of adenosine triphosphate (ATP) and H2O2 in citrus plants in response to ‘Candidatus Liberibacter asiaticus’ infection

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Candidatus Liberibacter asiaticus (Las) is a fastidious, phloem-restricted pathogen with a significantly reduced genome, and attacks all citrus species with no immune cultivars documented to date. Like other plant bacterial pathogens, Las deploys effector proteins into the organelles of plant cells,...

Multilocus microsatellite analysis of 'Candidatus Liberibacter asiaticus' associated with citrus Huanglongbing worldwide.

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Islam, Md-Sajedul; Glynn, Jonathan M; Bai, Yang; Duan, Yong-Ping; Coletta-Filho, Helvecio D; Kuruba, Gopal; Civerolo, Edwin L; Lin, Hong

2012-03-20

Huanglongbing (HLB) is one of the most destructive citrus diseases in the world. The disease is associated with the presence of a fastidious, phloem-limited α- proteobacterium, 'Candidatus Liberibacter asiaticus', 'Ca. Liberibacter africanus' or 'Ca. Liberibacter americanus'. HLB-associated Liberibacters have spread to North America and South America in recent years. While the causal agents of HLB have been putatively identified, information regarding the worldwide population structure and epidemiological relationships for 'Ca. L. asiaticus' is limited. The availability of the 'Ca. L. asiaticus' genome sequence has facilitated development of molecular markers from this bacterium. The objectives of this study were to develop microsatellite markers and conduct genetic analyses of 'Ca. L. asiaticus' from a worldwide collection. Two hundred eighty seven isolates from USA (Florida), Brazil, China, India, Cambodia, Vietnam, Taiwan, Thailand, and Japan were analyzed. A panel of seven polymorphic microsatellite markers was developed for 'Ca. L. asiaticus'. Microsatellite analyses across the samples showed that the genetic diversity of 'Ca. L. asiaticus' is higher in Asia than Americas. UPGMA and STRUCTURE analyses identified three major genetic groups worldwide. Isolates from India were genetically distinct. East-southeast Asian and Brazilian isolates were generally included in the same group; a few members of this group were found in Florida, but the majority of the isolates from Florida were clustered separately. eBURST analysis predicted three founder haplotypes, which may have given rise to three groups worldwide. Our results identified three major genetic groups of 'Ca. L. asiaticus' worldwide. Isolates from Brazil showed similar genetic makeup with east-southeast Asian dominant group, suggesting the possibility of a common origin. However, most of the isolates recovered from Florida were clustered in a separate group. While the sources of the dominant 'Ca. L

The ABC transporters in Candidatus Liberibacter asiaticus.

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Li, Wenlin; Cong, Qian; Pei, Jimin; Kinch, Lisa N; Grishin, Nick V

2012-11-01

Candidatus Liberibacter asiaticus (Ca. L. asiaticus) is a Gram-negative bacterium and the pathogen of Citrus Greening disease (Huanglongbing, HLB). As a parasitic bacterium, Ca. L. asiaticus harbors ABC transporters that play important roles in exchanging chemical compounds between Ca. L. asiaticus and its host. Here, we analyzed all the ABC transporter-related proteins in Ca. L. asiaticus. We identified 14 ABC transporter systems and predicted their structures and substrate specificities. In-depth sequence and structure analysis including multiple sequence alignment, phylogenetic tree reconstruction, and structure comparison further support their function predictions. Our study shows that this bacterium could use these ABC transporters to import metabolites (amino acids and phosphates) and enzyme cofactors (choline, thiamine, iron, manganese, and zinc), resist to organic solvent, heavy metal, and lipid-like drugs, maintain the composition of the outer membrane (OM), and secrete virulence factors. Although the features of most ABC systems could be deduced from the abundant experimental data on their orthologs, we reported several novel observations within ABC system proteins. Moreover, we identified seven nontransport ABC systems that are likely involved in virulence gene expression regulation, transposon excision regulation, and DNA repair. Our analysis reveals several candidates for further studies to understand and control the disease, including the type I virulence factor secretion system and its substrate that are likely related to Ca. L. asiaticus pathogenicity and the ABC transporter systems responsible for bacterial OM biosynthesis that are good drug targets. Copyright © 2012 Wiley Periodicals, Inc.

Heat treatment eliminates 'Candidatus Liberibacter asiaticus' from infected citrus trees under controlled conditions.

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Hoffman, Michele T; Doud, Melissa S; Williams, Lisa; Zhang, Mu-Qing; Ding, Fang; Stover, Ed; Hall, David; Zhang, Shouan; Jones, Lisa; Gooch, Mark; Fleites, Laura; Dixon, Wayne; Gabriel, Dean; Duan, Yong-Ping

2013-01-01

Huanglongbing (HLB) is one of the most destructive diseases of citrus worldwide. The three known causal agents of HLB are species of α-proteobacteria: 'Candidatus Liberibacter asiaticus', 'Ca. L. africanus', and 'Ca. L. americanus'. Previous studies have found distinct variations in temperature sensitivity and tolerance among these species. Here, we describe the use of controlled heat treatments to cure HLB caused by 'Ca. L. asiaticus', the most prevalent and heat-tolerant species. Using temperature-controlled growth chambers, we evaluated the time duration and temperature required to suppress or eliminate the 'Ca. L. asiaticus' bacterium in citrus, using various temperature treatments for time periods ranging from 2 days to 4 months. Results of quantitative polymerase chain reaction (qPCR) after treatment illustrate significant decreases in the 'Ca. L. asiaticus' bacterial titer, combined with healthy vigorous growth by all surviving trees. Repeated qPCR testing confirmed that previously infected, heat-treated plants showed no detectable levels of 'Ca. L. asiaticus', while untreated control plants remained highly infected. Continuous thermal exposure to 40 to 42°C for a minimum of 48 h was sufficient to significantly reduce titer or eliminate 'Ca. L. asiaticus' bacteria entirely in HLB-affected citrus seedlings. This method may be useful for the control of 'Ca. Liberibacter'-infected plants in nursery and greenhouse settings.

Changes in Variable Number of Tandem Repeats in 'Candidatus Liberibacter asiaticus' through Insect Transmission.

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Hiroshi Katoh

Full Text Available Citrus greening (huanglongbing is the most destructive citrus disease worldwide. The disease is associated with three species of 'Candidatus Liberibacter' among which 'Ca. Liberibacter asiaticus' has the widest distribution. 'Ca. L. asiaticus' is commonly transmitted by a phloem-feeding insect vector, the Asian citrus psyllid Diaphorina citri. A previous study showed that isolates of 'Ca. L. asiaticus' were clearly differentiated by variable number of tandem repeat (VNTR profiles at four loci in the genome. In this study, the VNTR analysis was further validated by assessing the stability of these repeats after multiplication of the pathogen upon host-to-host transmission using a 'Ca. L. asiaticus' strain from Japan. The results showed that some tandem repeats showed detectable changes after insect transmission. To our knowledge, this is the first report to demonstrate that the repeat numbers VNTR 002 and 077 of 'Ca. L. asiaticus' change through psyllid transmission. VNTRs in the recipient plant were apparently unrelated to the growing phase of the vector. In contrast, changes in the number of tandem repeats increased with longer acquisition and inoculation access periods, whereas changes were not observed through psyllid transmission after relatively short acquisition and inoculation access periods, up to 20 and 19 days, respectively.

Metabolite Profiling of Candidatus Liberibacter Infection in Hamlin Sweet Oranges.

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Hung, Wei-Lun; Wang, Yu

2018-04-18

Huanglongbing (HLB), also known as citrus greening disease, caused by Candidatus Liberibacter asiaticus (CLas), is considered the most serious citrus disease in the world. CLas infection has been shown to greatly affect metabolite profiles in citrus fruits. However, because of uneven distribution of CLas throughout the tree and a minimum bacterial titer requirement for polymerase chain reaction (PCR) detection, the infected trees may test false negative. To prevent this, metabolites of healthy Hamlin oranges (CLas-) obtained from the citrus undercover protection systems (CUPS) were investigated. Comparison of the metabolite profile of juice obtained from CLas- and CLas+ (asymptomatic and symptomatic) trees revealed significant differences in both volatile and nonvolatile metabolites. However, no consistent pattern could be observed in alcohols, esters, sesquiterpenes, sugars, flavanones, and limonoids as compared to previous studies. These results suggest that CLas may affect metabolite profiles of citrus fruits earlier than detecting infection by PCR. Citric acid, nobiletin, malic acid, and phenylalanine were identified as the metabolic biomarkers associated with the progression of HLB. Thus, the differential metabolites found in this study may serve as the biomarkers of HLB in its early stage, and the metabolite signature of CLas infection may provide useful information for developing a potential treatment strategy.

Horizontal gene acquisition of Liberibacter plant pathogens from a bacteriome-confined endosymbiont of their psyllid vector.

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Atsushi Nakabachi

Full Text Available he Asian citrus psyllid Diaphorina citri is a notorious agricultural pest that transmits the phloem-inhabiting alphaproteobacterial 'Candidatus Liberibacter asiaticus' and allied plant pathogens, which cause the devastating citrus disease called Huanglongbing or greening disease. D. citri harbors two distinct bacterial mutualists in the symbiotic organ called bacteriome: the betaproteobacterium 'Candidatus Profftella armatura' in the syncytial cytoplasm at the center of the bacteriome, and the gammaproteobacterium 'Candidatus Carsonella ruddii' in uninucleate bacteriocytes. Here we report that a putative amino acid transporter LysE of Profftella forms a highly supported clade with proteins of L. asiaticus, L. americanus, and L. solanacearum. L. crescens, the most basal Liberibacter lineage currently known, lacked the corresponding gene. The Profftella-Liberibacter subclade of LysE formed a clade with proteins from betaproteobacteria of the order Burkholderiales, to which Profftella belongs. This phylogenetic pattern favors the hypothesis that the Liberibacter lineage acquired the gene from the Profftella lineage via horizontal gene transfer (HGT after L. crescens diverged from other Liberibacter lineages. K A/K S analyses further supported the hypothesis that the genes encoded in the Liberibacter genomes are functional. These findings highlight the possible evolutionary importance of HGT between plant pathogens and their insect vector's symbionts that are confined in the symbiotic organ and seemingly sequestered from external microbial populations.

Quantitative distribution of 'Candidatus Liberibacter asiaticus' in citrus plants with citrus huanglongbing.

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Li, Wenbin; Levy, Laurene; Hartung, John S

2009-02-01

Citrus huanglongbing (HLB), or greening disease, is strongly associated with any of three nonculturable gram-negative bacteria belonging to 'Candidatus Liberibacter spp.' 'Ca. Liberibacter spp.' are transmitted by citrus psyllids to all commercial cultivars of citrus. The diseases can be lethal to citrus and have recently become widespread in both São Paulo, Brazil, and Florida, United States, the locations of the largest citrus industries in the world. Asiatic HLB, the form of the disease found in Florida, is associated with 'Ca. Liberibacter asiaticus' and is the subject of this report. The nonculturable nature of the pathogen has hampered research and little is known about the distribution of 'Ca. L. asiaticus' in infected trees. In this study, we have used a quantitative polymerase chain reaction assay to systematically quantify the distribution of 'Ca. L. asiaticus' genomes in tissues of six species of citrus either identified in the field during survey efforts in Florida or propagated in a greenhouse in Beltsville, MD. The populations of 'Ca. L. asiaticus' inferred from the distribution of 16S rDNA sequences specific for 'Ca. L. asiaticus' in leaf midribs, leaf blades, and bark samples varied by a factor of 1,000 among samples prepared from the six citrus species tested and by a factor of 100 between two sweet orange trees tested. In naturally infected trees, above-ground portions of the tree averaged 10(10) 'Ca. L. asiaticus' genomes per gram of tissue. Similar levels of 'Ca. L. asiaticus' genomes were observed in some but not all root samples from the same plants. In samples taken from greenhouse-inoculated trees, levels of 'Ca. L. asiaticus' genomes varied systematically from 10(4) genomes/g at the graft inoculation site to 10(10) genomes/g in some leaf petioles. Root samples from these trees also contained 'Ca. L. asiaticus' at 10(7) genomes/g. In symptomatic fruit tissues, 'Ca. L. asiaticus' genomes were also readily detected and quantified. The highest

Host and environmental factors influencing "Candidatus Liberibacter asiaticus" acquisition in Diaphorina citri.

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Wu, Fengnian; Huang, Jiaquan; Xu, Meirong; Fox, Eduardo G P; Beattie, G Andrew C; Holford, Paul; Cen, Yijing; Deng, Xiaoling

2018-05-03

Diaphorina citri is a vector of "Candidatus Liberibacter asiaticus" (CLas) associated with citrus Huanglongbing. In this study, the infection and titers of CLas in the psyllid, were monitored for life cycle stage, sex, host-plant CLas titer, host-plant genotype, and ambient temperature. Acquisition efficiency of CLas by D. citri was highest in nymphs reared at 25 °C on a host plant with high CLas titers but was independent of the host genotypes assessed and of vector sex. We further observed that D. citri nymphs acquired CLas more rapidly than adults based on acquisition access periods (AAPs). CLas did not multiply in the alimentary canal, hemolymph, and salivary glands of adults for 18 d after a 3-day AAP as adult. However, CLas multiplication was detected in hemolymph and salivary gland of adults after the bacterium was acquired by nymphs. Eighty percent of salivary glands of adults contained CLas 18 d after a 3-day AAP as nymph compared to 10% 18 d after a 3-day AAP as adults. Different factors tested herein influenced CLas acquisition efficiency of D. citri, CLas multiplication and spread inside the psyllid. These observations serve to better understand mechanisms of CLas infection in D. citri. This article is protected by copyright. All rights reserved.

Infection Density Dynamics of the Citrus Greening Bacterium “Candidatus Liberibacter asiaticus” in Field Populations of the Psyllid Diaphorina citri and Its Relevance to the Efficiency of Pathogen Transmission to Citrus Plants

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Ukuda-Hosokawa, Rie; Sadoyama, Yasutsune; Kishaba, Misaki; Kuriwada, Takashi; Anbutsu, Hisashi

2015-01-01

Huanglongbing, or citrus greening, is a devastating disease of citrus plants recently spreading worldwide, which is caused by an uncultivable bacterial pathogen, “Candidatus Liberibacter asiaticus,” and vectored by a phloem-sucking insect, Diaphorina citri. We investigated the infection density dynamics of “Ca. Liberibacter asiaticus” in field populations of D. citri with experiments using field-collected insects to address how “Ca. Liberibacter asiaticus” infection density in the vector insect is relevant to pathogen transmission to citrus plants. Of 500 insects continuously collected from “Ca. Liberibacter asiaticus”-infected citrus trees with pathological symptoms in the spring and autumn of 2009, 497 (99.4%) were “Ca. Liberibacter asiaticus” positive. The infections were systemic across head-thorax and abdomen, ranging from 103 to 107 bacteria per insect. In spring, the infection densities were low in March, at ∼103 bacteria per insect, increasing up to 106 to 107 bacteria per insect in April and May, and decreasing to 105 to 106 bacteria per insect in late May, whereas the infection densities were constantly ∼106 to 107 bacteria per insect in autumn. Statistical analysis suggested that several factors, such as insect sex, host trees, and collection dates, may be correlated with “Ca. Liberibacter asiaticus” infection densities in field D. citri populations. Inoculation experiments with citrus seedlings using field-collected “Ca. Liberibacter asiaticus”-infected insects suggested that (i) “Ca. Liberibacter asiaticus”-transmitting insects tend to exhibit higher infection densities than do nontransmitting insects, (ii) a threshold level (∼106 bacteria per insect) of “Ca. Liberibacter asiaticus” density in D. citri is required for successful transmission to citrus plants, and (iii) D. citri attaining the threshold infection level transmits “Ca. Liberibacter asiaticus” to citrus plants in a stochastic manner. These

Diaphorina citri (Hemiptera: Liviidae) Vector Competence for the Citrus Greening Pathogen 'Candidatus Liberibacter Asiaticus'.

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Tabachnick, Walter J

2015-06-01

Characterizing the vector competence of Diaphorina citri Kuwayama for 'Candidatus Liberibacter asiaticus,' the pathogen causing citrus greening, is essential for understanding the epidemiology of this disease that is threatening the U.S. citrus industry. Vector competence studies have been difficult because of the biology of D. citri, the inability to culture the pathogen, and the available diagnostic methods used to detect the bacteria in plant and insect tissues. The methods employed in many studies of D. citri vector competence may have overestimated amounts of live 'Ca. L. asiaticus' in both plant and insect tissues, and it is possible that the amounts of phloem ingested by psyllids may not contain sufficient detectable pathogen using current diagnostic methods. As a result of the difficulty in characterizing D. citri vector competence, the several daunting challenges for providing D. citri that are unable to inoculate 'Ca. L. asiaticus', as a novel method to control greening are discussed. Suggestions to overcome some of these challenges are provided. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Comparative proteomic analysis of hemolymph from uninfected and Candidatus Liberibacter asiaticus-infected Diaphorina citri.

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Gill, T A; Chu, C; Pelz-Stelinski, K S

2017-02-01

Hemolymph was characterized from Diaphorina citri adults infected with the phytopathogen, Candidatus Liberibacter asiaticus (CLas), and compared with that from uninfected psyllids. This study identified 5531 and 3220 peptides within infected and uninfected hemolymph using nano-LC-MS/MS. A reduced number of proteins were detected for D. citri and all known endosymbionts within infected hemolymph as compared to uninfected hemolymph. A large number of immune defense proteins were absent from D. citri hemolymph; however, a single recognition protein (PGRP), two serine protease inhibitors, three prophenoloxidase (proPO) enzymes, and a single serine protease in an uninfected D. citri were detected. The hemolymph is nearly devoid of nutrient storage proteins. This is the first proteomic analysis of D. citri hemolymph that also analyses the components contributed by all the endosymbionts. By comparing the contribution of each endosymbiont (CCR, CPA, and WB) in the presence and absence of CLas infection, this study offers initial insights regarding the hemolymph response to microbial community shifts associated with D. citri infection status. Our data also present potential protein targets for analysis and disruption of CLas transmission that may facilitate management of huanglongbing (HLB) caused by CLas in citrus.

Infection Density Dynamics of the Citrus Greening Bacterium "Candidatus Liberibacter asiaticus" in Field Populations of the Psyllid Diaphorina citri and Its Relevance to the Efficiency of Pathogen Transmission to Citrus Plants.

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Ukuda-Hosokawa, Rie; Sadoyama, Yasutsune; Kishaba, Misaki; Kuriwada, Takashi; Anbutsu, Hisashi; Fukatsu, Takema

2015-06-01

Huanglongbing, or citrus greening, is a devastating disease of citrus plants recently spreading worldwide, which is caused by an uncultivable bacterial pathogen, "Candidatus Liberibacter asiaticus," and vectored by a phloem-sucking insect, Diaphorina citri. We investigated the infection density dynamics of "Ca. Liberibacter asiaticus" in field populations of D. citri with experiments using field-collected insects to address how "Ca. Liberibacter asiaticus" infection density in the vector insect is relevant to pathogen transmission to citrus plants. Of 500 insects continuously collected from "Ca. Liberibacter asiaticus"-infected citrus trees with pathological symptoms in the spring and autumn of 2009, 497 (99.4%) were "Ca. Liberibacter asiaticus" positive. The infections were systemic across head-thorax and abdomen, ranging from 10(3) to 10(7) bacteria per insect. In spring, the infection densities were low in March, at ∼ 10(3) bacteria per insect, increasing up to 10(6) to 10(7) bacteria per insect in April and May, and decreasing to 10(5) to 10(6) bacteria per insect in late May, whereas the infection densities were constantly ∼ 10(6) to 10(7) bacteria per insect in autumn. Statistical analysis suggested that several factors, such as insect sex, host trees, and collection dates, may be correlated with "Ca. Liberibacter asiaticus" infection densities in field D. citri populations. Inoculation experiments with citrus seedlings using field-collected "Ca. Liberibacter asiaticus"-infected insects suggested that (i) "Ca. Liberibacter asiaticus"-transmitting insects tend to exhibit higher infection densities than do nontransmitting insects, (ii) a threshold level (∼ 10(6) bacteria per insect) of "Ca. Liberibacter asiaticus" density in D. citri is required for successful transmission to citrus plants, and (iii) D. citri attaining the threshold infection level transmits "Ca. Liberibacter asiaticus" to citrus plants in a stochastic manner. These findings provide

Multiplex real-time PCR for detection, identification and quantification of 'Candidatus Liberibacter solanacearum' in potato plants with zebra chip.

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Li, Wenbin; Abad, Jorge A; French-Monar, Ronald D; Rascoe, John; Wen, Aimin; Gudmestad, Neil C; Secor, Gary A; Lee, Ing-Ming; Duan, Yongping; Levy, Laurene

2009-07-01

The new Liberibacter species, 'Candidatus Liberibacter solanacearum' (Lso) recently associated with potato/tomato psyllid-transmitted diseases in tomato and capsicum in New Zealand, was found to be consistently associated with a newly emerging potato zebra chip (ZC) disease in Texas and other southwestern states in the USA. A species-specific primer LsoF was developed for both quantitative real-time PCR (qPCR) and conventional PCR (cPCR) to detect and quantify Lso in infected samples. In multiplex qPCR, a plant cytochrome oxidase (COX)-based probe-primer set was used as a positive internal control for host plants, which could be used to reliably access the DNA extraction quality and to normalize qPCR data for accurate quantification of the bacterial populations in environment samples. Neither the qPCR nor the cPCR using the primer and/or probe sets with LsoF reacted with other Liberibacter species infecting citrus or other potato pathogens. The low detection limit of the multiplex qPCR was about 20 copies of the target 16S rDNA templates per reaction for field samples. Lso was readily detected and quantified in various tissues of ZC-affected potato plants collected from fields in Texas. A thorough but uneven colonization of Lso was revealed in various tissues of potato plants. The highest Lso populations were about 3x10(8) genomes/g tissue in the root, which were 3-order higher than those in the above-ground tissues of potato plants. The Lso bacterial populations were normally distributed across the ZC-affected potato plants collected from fields in Texas, with 60% of ZC-affected potato plants harboring an average Lso population from 10(5) to 10(6) genomes/g tissue, 4% of plants hosting above 10(7) Lso genomes/g tissue, and 8% of plants holding below 10(3) Lso genomes/g tissue. The rapid, sensitive, specific and reliable multiplex qPCR showed its potential to become a powerful tool for early detection and quantification of the new Liberibacter species associated

PHLOEM PROMOTERS IN TRANSGENIC SWEET ORANGE ARE DIFFERENTIALLY TRIGGERED BY Candidatus Liberibacter asiaticus

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LUZIA YURIKO MIYATA

Full Text Available ABSTRACT The use of promoters preferentially expressed in specific plant tissues is a desirable strategy to search for resistance for pathogens that colonize these tissues. The bacterium Candidatus Liberibacter asiaticus (Las, associated with huanglongbing disease (HLB of citrus, colonizes phloem vessels. Some promoters, besides conferring tissue-specific expression, can also respond to the presence of the pathogen. The objective of the present study was to verify if the presence of Las could modulate the activation of the phloem-specific promoters AtPP2 (Arabidopsis thaliana phloem protein 2, AtSUC2 (A. thaliana sucrose transporter 2 and CsPP2 ( pCitrus phloemrotein 2, known to be expressed in Citrus sinensis phloem. ‘Hamlin’ sweet orange plants (Citrus sinensis L. Osbeck transformed with the uidA (GUS reporter gene under the control of AtPP2, AtSUC2 and CsPP2 promoters were infected to evaluate the interdependence between transgene expression and the concentration of Las. Plants were inoculated with Las by Diaphorina citri and eighteen months later, bacterial concentration and uidA expression were determined by qPCR and RT-qPCR, respectively. Reporter gene expression driven by AtSUC2 promoter was strongly and positively correlated with Las concentration. Therefore, this promoter combines desirable features of both tissue-specificity and pathogen-inducibility for the production of transgenic plants tolerant to Las.

Morphological abnormalities and cell death in the Asian citrus psyllid (Diaphorina citri) midgut associated with Candidatus Liberibacter asiaticus.

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Ghanim, Murad; Fattah-Hosseini, Somayeh; Levy, Amit; Cilia, Michelle

2016-09-15

Candidatus Liberibacter asiaticus (CLas) is a phloem-limited, gram-negative, fastidious bacterium that is associated with the development of citrus greening disease, also known as Huanglongbing (HLB). CLas is transmitted by the Asian citrus psyllid (ACP) Diaphorina citri, in a circulative manner. Two major barriers to transmission within the insect are the midgut and the salivary glands. We performed a thorough microscopic analysis within the insect midgut following exposure to CLas-infected citrus trees. We observed changes in nuclear architecture, including pyknosis and karyorrhexis as well as changes to the actin cytoskeleton in CLas-exposed midgut cells. Further analyses showed that the changes are likely due to the activation of programmed cell death as assessed by Annexin V staining and DNA fragmentation assays. These results suggest that exposure to CLas-infected trees induces apoptotic responses in the psyllid midgut that should be further investigated. Understanding the adaptive significance of the apoptotic response has the potential to create new approaches for controlling HLB.

Colonization of citrus seed coats by 'Candidatus Liberibacter asiaticus': implications for seed transmission of the bacterium.

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Hilf, Mark E

2011-10-01

Huanglongbing is an economically damaging disease of citrus associated with infection by 'Candidatus Liberibacter asiaticus'. Transmission of the organism via infection of seeds has not been demonstrated but is a concern since some citrus varieties, particularly those used as rootstocks in commercial plantings are propagated from seed. We compared the incidence of detection of 'Ca. Liberibacter asiaticus' DNA in individual fruit peduncles, seed coats, seeds, and in germinated seedlings from 'Sanguenelli' sweet orange and 'Conners' grapefruit fruits sampled from infected trees. Using real-time quantitative PCR (qPCR) we detected pathogen DNA in nucleic acid extracts of 36 and 100% of peduncles from 'Sanguenelli' and from 'Conners' fruits, respectively. We also detected pathogen DNA in extracts of 37 and 98% of seed coats and in 1.6 and 4% of extracts from the corresponding seeds of 'Sanguenelli' and 'Conners', respectively. Small amounts of pathogen DNA were detected in 10% of 'Sanguenelli' seedlings grown in the greenhouse, but in none of 204 extracts from 'Conners' seedlings. Pathogen DNA was detected in 4.9% and in 89% of seed coats peeled from seeds of 'Sanguenelli' and 'Conners' which were germinated on agar, and in 5% of 'Sanguenelli' but in none of 164 'Conners' seedlings which grew from these seeds on agar. No pathogen DNA was detected in 'Ridge Pineapple' tissue at 3 months post-grafting onto 'Sanguenelli' seedlings, even when pathogen DNA had been detected initially in the 'Sanguenelli' seedling. Though the apparent colonization of 'Conners' seeds was more extensive and nearly uniform compared with 'Sanguenelli' seeds, no pathogen DNA was detected in 'Conners' seedlings grown from these seeds. For either variety, no association was established between the presence of pathogen DNA in fruit peduncles and seed coats and in seedlings.

Incidence of 'Candidatus Liberibacter asiaticus'-Infected Plants Among Citrandarins as Rootstock and Scion Under Field Conditions.

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Boava, Leonardo Pires; Sagawa, Cíntia Helena Duarte; Cristofani-Yaly, Mariângela; Machado, Marcos Antonio

2015-04-01

Huanglongbing (HLB), caused by the bacterium 'Candidatus Liberibacter' spp., is currently one of the most serious diseases of citrus plants and has caused substantial economic losses. Thus far, there is no source of genetic resistance to HLB in the genus Citrus or its relatives. However, several studies have reported Poncirus trifoliata and some of its hybrids to be more tolerant to the disease. The main objective of this study was to report differences in the incidence of 'Ca. L. asiaticus' infection in citrandarin plants, hybrids from Sunki mandarin (Citrus sunki (Hayata) hort. ex Tanaka), and trifoliate orange Rubidoux (P. trifoliata (L.) Raf.)), after conducting an extensive survey under field conditions. These hybrid plants were established for approximately 7 years in an area with a high incidence of 'Ca. L. asiaticus'-infected plants. We selected two experimental areas (area A and area B), located approximately 10 m apart. Area A consists of Pera sweet orange (C. sinensis (L.) Osb.) grafted onto 56 different citrandarin rootstocks. Area B consists of citrandarin scions grafted onto Rangpur lime (C. limonia Osb.) rootstock. Bacteria in the leaves and roots were detected using real-time quantitative polymerase chain reaction. The incidence of 'Ca. L. asiaticus'-infected plants was 92% in area A and 14% in area B. Because infected plants occurred in both areas, we examined whether the P. trifoliata hybrid rootstock influenced HLB development and also determined the distribution of 'Ca. L. asiaticus' in Citrus tree tissues. Although this survey does not present evidence regarding the resistance of P. trifoliata and its hybrids in relation to bacteria or psyllids, future investigation, mainly using the most promising hybrids for response to 'Ca. L. asiaticus', will help us to understand the probable mechanism of defense or identifying compounds in P. trifoliata and its hybrids that are very important as strategy to combat HLB. Details of these results are

Prophage-mediated dynamics of 'Candidatus Liberibacter asiaticus' populations, the destructive bacterial pathogens of citrus huanglongbing.

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Lijuan Zhou

Full Text Available Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus' (Las Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB, a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by screening clone libraries of infected citrus, periwinkle and psyllids. Among them, Types A and B share highly conserved sequences and localize within the two prophages, FP1 and FP2, respectively. Although Types B and C were abundant in all three libraries, Type A was much more abundant in the libraries from the Las-infected psyllids than from the Las-infected plants, and Type D was only identified in libraries from the infected host plants but not from the infected psyllids. Sequence analysis of these variants revealed that the variations may result from recombination and rearrangement events. Conventional PCR results using type-specific molecular markers indicated that A, B, C and D are the four most abundant types in Las-infected citrus and periwinkle. However, only three types, A, B and C are abundant in Las-infected psyllids. Typing results for Las-infected citrus field samples indicated that mixed populations of Las bacteria present in Floridian isolates, but only the Type D population was correlated with the blotchy mottle symptom. Extended cloning and sequencing of the Type D region revealed a third prophage/phage in the Las genome, which may derive from the recombination of FP1 and FP2. Dramatic variations in these prophage regions were also found among the global Las isolates. These results are the first to demonstrate the prophage/phage-mediated dynamics of Las populations in plant and insect hosts, and their correlation with insect transmission and

Prophage-mediated dynamics of 'Candidatus Liberibacter asiaticus' populations, the destructive bacterial pathogens of citrus huanglongbing.

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Zhou, Lijuan; Powell, Charles A; Li, Wenbin; Irey, Mike; Duan, Yongping

2013-01-01

Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus' (Las) Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB), a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by screening clone libraries of infected citrus, periwinkle and psyllids. Among them, Types A and B share highly conserved sequences and localize within the two prophages, FP1 and FP2, respectively. Although Types B and C were abundant in all three libraries, Type A was much more abundant in the libraries from the Las-infected psyllids than from the Las-infected plants, and Type D was only identified in libraries from the infected host plants but not from the infected psyllids. Sequence analysis of these variants revealed that the variations may result from recombination and rearrangement events. Conventional PCR results using type-specific molecular markers indicated that A, B, C and D are the four most abundant types in Las-infected citrus and periwinkle. However, only three types, A, B and C are abundant in Las-infected psyllids. Typing results for Las-infected citrus field samples indicated that mixed populations of Las bacteria present in Floridian isolates, but only the Type D population was correlated with the blotchy mottle symptom. Extended cloning and sequencing of the Type D region revealed a third prophage/phage in the Las genome, which may derive from the recombination of FP1 and FP2. Dramatic variations in these prophage regions were also found among the global Las isolates. These results are the first to demonstrate the prophage/phage-mediated dynamics of Las populations in plant and insect hosts, and their correlation with insect transmission and disease development.

Genetic diversity of Candidatus Liberibacter asiaticus based on two hypervariable effector genes in Thailand.

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Puttamuk, Thamrongjet; Zhou, Lijuan; Thaveechai, Niphone; Zhang, Shouan; Armstrong, Cheryl M; Duan, Yongping

2014-01-01

Huanglongbing (HLB), also known as citrus greening, is one of the most destructive diseases of citrus worldwide. HLB is associated with three species of 'Candidatus Liberibacter' with 'Ca. L. asiaticus' (Las) being the most widely distributed around the world, and the only species detected in Thailand. To understand the genetic diversity of Las bacteria in Thailand, we evaluated two closely-related effector genes, lasAI and lasAII, found within the Las prophages from 239 infected citrus and 55 infected psyllid samples collected from different provinces in Thailand. The results indicated that most of the Las-infected samples collected from Thailand contained at least one prophage sequence with 48.29% containing prophage 1 (FP1), 63.26% containing prophage 2 (FP2), and 19.38% containing both prophages. Interestingly, FP2 was found to be the predominant population in Las-infected citrus samples while Las-infected psyllids contained primarily FP1. The multiple banding patterns that resulted from amplification of lasAI imply extensive variation exists within the full and partial repeat sequence while the single band from lasAII indicates a low amount of variation within the repeat sequence. Phylogenetic analysis of Las-infected samples from 22 provinces in Thailand suggested that the bacterial pathogen may have been introduced to Thailand from China and the Philippines. This is the first report evaluating the genetic variation of a large population of Ca. L. asiaticus infected samples in Thailand using the two effector genes from Las prophage regions.

Latency and Persistence of 'Candidatus Liberibacter asiaticus' in Its Psyllid Vector, Diaphorina citri (Hemiptera: Liviidae).

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Canale, Maria Cristina; Tomaseto, Arthur Fernando; Haddad, Marineia de Lara; Della Coletta-Filho, Helvécio; Lopes, João Roberto Spotti

2017-03-01

Although 'Candidatus Liberibacter asiaticus' (Las) is a major pathogen associated with citrus huanglongbing (HLB), some characteristics of transmission by the psyllid vector Diaphorina citri are not fully understood. We examined the latent period and persistence of transmission of Las by D. citri in a series of experiments at 25°C, in which third-instar psyllid nymphs and 1-week-old adults were confined on infected citrus for an acquisition access period (AAP), and submitted to sequential inoculation access periods (IAPs) on healthy citrus seedlings. The median latent period (LP 50 , i.e., acquisition time after which 50% of the individuals can inoculate) of 16.8 and 17.8 days for psyllids that acquired Las as nymphs and adults, respectively, was determined by transferring single individuals in 48-h IAPs. Inoculation events were intermittent and randomly distributed over the IAPs, but were more frequent after acquisition by nymphs. A minimum latent period of 7 to 10 days was observed by transferring groups of 10 psyllids in 48-h IAPs, after a 96-h AAP by nymphs. Psyllids transmitted for up to 5 weeks, when submitted to sequential 1-week IAPs after a 14-day AAP as nymphs. The long latent period and persistence of transmission are indirect evidences of circulative propagation of Las in D. citri.

Predominance of Single Prophage Carrying a CRISPR/cas System in "Candidatus Liberibacter asiaticus" Strains in Southern China.

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Zheng, Zheng; Bao, Minli; Wu, Fengnian; Chen, Jianchi; Deng, Xiaoling

2016-01-01

"Candidatus Liberibacter asiaticus" (CLas) is an uncultureable α-proteobacterium associated with citrus Huanglongbing (HLB, yellow shoot disease), a highly destructive disease affecting citrus production worldwide. HLB was observed in Guangdong Province of China over a hundred years ago and remains endemic there. Little is known about CLas biology due to its uncultureable nature. This study began with the genome sequence analysis of CLas Strain A4 from Guangdong in the prophage region. Within the two currently known prophage types, Type 1 (SC1-like) and Type 2 (SC2-like), A4 genome contained only a Type 2 prophage, CGdP2, namely. An analysis on CLas strains collected in Guangdong showed that Type 2 prophage dominated the bacterial population (82.6%, 71/86). An extended survey covering five provinces in southern China also revealed the predominance of single prophage (Type 1 or Type 2) in the CLas population (90.4%, 169/187). CLas strains with two and no prophage types accounted for 7.2% and 2.8%, respectively. In silico analyses on CGdP2 identified a CRISPR (clustered regularly interspaced short palindromic repeats)/cas (CRISPR-associated protein genes) system, consisting of four 22 bp repeats, three 23 bp spacers and 9 predicted cas. Similar CRISPR/cas systems were detected in all 10 published CLas prophages as well as 13 CLas field strains in southern China. Both Type 1 and Type 2 prophages shared almost identical sequences in spacer 1 and 3 but not spacer 2. Considering that the function of a CRISPR/cas system was to destroy invading DNA, it was hypothesized that a pre-established CLas prophage could use its CRISPR/cas system guided by spacer 1 and/or 3 to defeat the invasion of the other phage/prophage. This hypothesis explained the predominance of single prophage type in the CLas population in southern China. This is the first report of CRISPR/cas system in the "Ca. Liberibacter" genera.

Comparative transcriptome analysis unveils the tolerance mechanisms of Citrus hystrix in response to 'Candidatus Liberibacter asiaticus' infection.

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Yan Hu

Full Text Available Citrus Huanglongbing (HLB, a highly devastating citrus disease, is associated with 'Candidatus Liberibacter asiacitus' (CLas, a member of phloem-inhabiting α-proteobacteria. HLB can affect all cultivated citrus and no cure is currently available. Previous studies showed that Kaffir lime (Citrus hystrix, primarily grown in South Asia and Southeast Asia, was tolerant to HLB but the molecular mechanism remains unknown. In this study, gene expression profiling experiments were performed on HLB-tolerant C. hystrix and HLB-susceptible C. sinensis three months after inoculation with CLas using RNA-seq data. Differentially expressed genes (DEGs in the two citrus cultivars were mainly involved in diverse cellular functions including carbohydrate metabolism, photosynthesis, cell wall metabolism, secondary metabolism, hormone metabolism and oxidation/reduction processes. Notably, starch synthesis and photosynthesis process were not disturbed in CLas-infected C. hystrix. Most of the DEGs involved in cell wall metabolism and secondary metabolism were up-regulated in C. hystrix. In addition, the activation of peroxidases, Cu/Zn-SOD and POD4, may also enhance the tolerance of C. hystrix to CLas. This study provides an insight into the host response of HLB-tolerant citrus cultivar to CLas. C. hystrix is potentially useful for HLB-tolerant/resistant citrus breeding in the future.

Transmission of 'Candidatus Liberibacter solanacearum' by Bactericera trigonica Hodkinson to vegetable hosts

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Teresani, G.R.; Hernández, E.; Bertolini, E.; Siverio, F.; Moreno, A.; Fereres, A.; Cambra, M.

2017-07-01

The bacterium ‘Candidatus Liberibacter solanacearum’ is a recent plant pathogen of several crops in Solanaceae and Apiaceae and is associated with economically important diseases. The bacterium is a carrot seed borne pathogen that can also be transmitted from potato mother tubers and by psyllid vectors. The psyllid Bactericera trigonica Hodkinson was described carrying CaLso associated with vegetative disorders in carrot and celery crops in Spain and its competence to transmit this phloem-limited bacterium among vegetables is currently being investigated. Here electrical penetration graphs showed that B. trigonica fed in the phloem of carrot and celery and probed the phloem in potato, but not in tomato plants. The bacterium was efficiently transmitted to carrot and celery plants when either single B. trigonica or groups of ten fed on these species. An inoculation access period of 24 hours was sufficient for a single B. trigonica to transmit the bacterium to carrot (67.8%), celery (21.1%) and eventually to potato and tomato (6.0%). Higher transmission rates were obtained with 10 individuals on celery (100%), carrot (80%), potato (10%) and tomato (10%). Bactericera trigonica laid eggs, and the hatched nymphs develop into adult on carrot and celery, but not on potato and tomato. CaLso was detected in 20% of the eggs laid by females carrying the bacterium. The results confirmed that B. trigonica is a vector of the bacterium to carrot and celery, and it is discussed the potential role of this psyllid in the transmission of the pathogen to potato and tomato plants.

Search for potential vectors of ‘Candidatus Liberibacter solanacearum’: population dynamics in host crops

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Teresani, G.; Hernández, E.; Bertolini, E.; Siverio, F.; Marroquín, C.; Molina, J.; Hermoso de Mendoza, A.; Cambra, M.

2015-07-01

‘Candidatus Liberibacter solanacearum’ has recently been reported to be associated with vegetative disorders and economic losses in carrot and celery crops in Spain. The bacterium is a carrot seedborne pathogen and it is transmitted by psyllid vector species. From 2011 to 2014 seasonal and occasional surveys in carrot, celery and potato plots were performed. The sticky plant method was used to monitor the arthropods that visited the plants. The collected arthropods were classified into Aphididae and Cicadellidae, and the superfamily Psylloidea was identified to the species level. The superfamily Psylloidea represented 35.45% of the total arthropods captured on celery in Villena and 99.1% on carrot in Tenerife (Canary Islands). The maximum flight of psyllid species was in summer, both in mainland Spain and the Canary Islands, reaching a peak of 570 specimens in August in Villena and 6,063 in July in Tenerife. The main identified psyllid species were as follows: Bactericera trigonica Hodkinson, B. tremblayi Wagner and B. nigricornis Förster. B. trigonica represented more than 99% of the psyllids captured in the Canary Islands and 75% and 38% in 2011 and 2012 in Villena, respectively. In addition, Trioza urticae Linnaeus, Bactericera sp., Ctenarytaina sp., Cacopsylla sp., Trioza sp. and Psylla sp. were captured. ‘Ca. L. solanacearum’ targets were detected by squash real-time PCR in 19.5% of the psyllids belonging to the different Bactericera species. This paper reports at least three new psyllid species that carry the bacterium and can be considered as potential vectors. (Author)

Transmission of 'Candidatus Liberibacter solanacearum' by Bactericera trigonica Hodkinson to vegetable hosts

International Nuclear Information System (INIS)

Teresani, G.R.; Hernández, E.; Bertolini, E.; Siverio, F.; Moreno, A.; Fereres, A.; Cambra, M.

2017-01-01

The bacterium ‘Candidatus Liberibacter solanacearum’ is a recent plant pathogen of several crops in Solanaceae and Apiaceae and is associated with economically important diseases. The bacterium is a carrot seed borne pathogen that can also be transmitted from potato mother tubers and by psyllid vectors. The psyllid Bactericera trigonica Hodkinson was described carrying CaLso associated with vegetative disorders in carrot and celery crops in Spain and its competence to transmit this phloem-limited bacterium among vegetables is currently being investigated. Here electrical penetration graphs showed that B. trigonica fed in the phloem of carrot and celery and probed the phloem in potato, but not in tomato plants. The bacterium was efficiently transmitted to carrot and celery plants when either single B. trigonica or groups of ten fed on these species. An inoculation access period of 24 hours was sufficient for a single B. trigonica to transmit the bacterium to carrot (67.8%), celery (21.1%) and eventually to potato and tomato (6.0%). Higher transmission rates were obtained with 10 individuals on celery (100%), carrot (80%), potato (10%) and tomato (10%). Bactericera trigonica laid eggs, and the hatched nymphs develop into adult on carrot and celery, but not on potato and tomato. CaLso was detected in 20% of the eggs laid by females carrying the bacterium. The results confirmed that B. trigonica is a vector of the bacterium to carrot and celery, and it is discussed the potential role of this psyllid in the transmission of the pathogen to potato and tomato plants.

Detección de Ca Liberibacter solanacearum y fitoplasmas en cultivo de papa (Solanum tuberosum L. en el Valle de Toluca

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Ana Tarin Gutiérrez-Ibáñez

2013-01-01

Full Text Available Título en ingles: Detection of Ca Liberibacter solanacearum and phytoplasma in potato crop (Solanum tuberosum L. in Toluca Valley Título corto: Detección de Ca Liberibacter solanacearum y fitoplasmas Resumen En México y Centro América se han detectado tubérculos de papa con manchado interno. Recientemente en Texas EUA a esta enfermedad se le ha denominado “Zebra Chip” (ZC o rayado de la papa, los síntomas foliares se asemejan al síndrome denominado “Punta Morada de la Papa” (PMP o enfermedad del “amarillamiento por psilidos” la cual es asociada con la presencia de “Candidatus Liberibacter solanacearum”. El objetivo de esta investigación fue detectar la presencia de esta bacteria y de fitoplasmas en plantas de papa que presentaban la coloración purpura de los foliolos. Durante el ciclo primavera – verano 2011 y 2012 se hizo un muestreo en los municipios de Tenango del Valle, Zinacantepec, Villa de Allende y San José del Rincón, del Estado de México. La detección de ambos patógenos se realizó mediante la reacción en cadena de la polimerasa (PCR con los iniciadores específicos para fitoplasmas: P1/P7, R16mF2/R16mR1 y para Ca Liberibacter solanacearum: OA2/Oi2c, resultando el 35,8% de las plantas positivas para fitoplasmas y el 11,6% para la bacteria. Los resultados indican  que en algunas regiones productoras de papa del Estado de México,  los dos presuntos agentes causales del síndrome de  PMP, fitoplasmas y Ca. Liberibacter solanacearum, pueden estar asociados. Palabras clave: Candidatus Liberibacter solanacearum; Fitoplasma; punta morada. Abstract In Mexico and Central America have been detected stained potato tubers with internal browning; recently in Texas, USA, this disease has been called "Zebra Chip" (ZC or striped potato, foliar symptoms resemble the syndrome called "Potato Purple Top" (PPT or "psyllid yellows" disease which is associated with the presence of "Candidatus liberibacter solanacearum�

Effects of Candidatus Liberibacter asiaticus on the fitness of the vector Diaphorina citri.

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Ren, S-L; Li, Y-H; Zhou, Y-T; Xu, W-M; Cuthbertson, A G S; Guo, Y-J; Qiu, B-L

2016-12-01

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama transmits the bacterium 'Candidatus Liberibacter asiaticus' (Las), which causes citrus huanglongbing (HLB) disease. Although many studies have been conducted on the biology of ACP on different host plants, few have taken the plant, Las bacteria and the vector insect within one context to evaluate the effects of Las on the fitness of ACP under field conditions. Understanding the relationship between Las and ACP is critical for both ACP and HLB disease management. We estimated the development and survival of ACP immatures, the longevity and fecundity of ACP female adults in four treatments (Las-positive or -negative ACP on Las-infected and -free citrus plants). Las-positive ACP immatures developed significantly faster on Las-infected citrus than those on Las-free plants. The fecundity and longevity of Las-positive female adults were also greater, or longer on Las-infected citrus shoots, whereas the survival of Las-positive immatures was significantly lower on Las-infected citrus shoots, compared to those that developed on Las-free plants. Similarly, the intrinsic rate of population increase (r m ) was highest (0·1404) when Las-positive ACP fed on Las-infected citrus shoots and the lowest (0·1328) when the Las-negative ACP fed on Las-free citrus shoots. Both the Las infection in ACP and citrus plants had obvious effects on the biology of ACP. When compared to the Las infection in ACP insects, the Las infection in citrus shoots had a more significant effect on the fitness of ACP. To efficiently prevent the occurrence and spread of HLB disease, it is critical to understand the ecological basis of vector outbreaks and disease incidence, especially under field conditions. Thus, this study has increased our understanding of the epidemiology of HLB transmitted by psyllids in nature. © 2016 The Society for Applied Microbiology.

Genomic sequence of 'Candidatus Liberibacter solanacearum' haplotype C and its comparison with haplotype A and B genomes.

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Jinhui Wang

Full Text Available Haplotypes A and B of 'Candidatus Liberibacter solanacearum' (CLso are associated with diseases of solanaceous plants, especially Zebra chip disease of potato, and haplotypes C, D and E are associated with symptoms on apiaceous plants. To date, one complete genome of haplotype B and two high quality draft genomes of haplotype A have been obtained for these unculturable bacteria using metagenomics from the psyllid vector Bactericera cockerelli. Here, we present the first genomic sequences obtained for the carrot-associated CLso. These two genomic sequences of haplotype C, FIN114 (1.24 Mbp and FIN111 (1.20 Mbp, were obtained from carrot psyllids (Trioza apicalis harboring CLso. Genomic comparisons between the haplotypes A, B and C revealed that the genome organization differs between these haplotypes, due to large inversions and other recombinations. Comparison of protein-coding genes indicated that the core genome of CLso consists of 885 ortholog groups, with the pan-genome consisting of 1327 ortholog groups. Twenty-seven ortholog groups are unique to CLso haplotype C, whilst 11 ortholog groups shared by the haplotypes A and B, are not found in the haplotype C. Some of these ortholog groups that are not part of the core genome may encode functions related to interactions with the different host plant and psyllid species.

Sexual transmission of a plant pathogenic bacterium, Candidatus Liberibacter asiaticus, between conspecific insect vectors during mating.

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Rajinder S Mann

Full Text Available Candidatus Liberibacter asiaticus is a fastidious, phloem-inhabiting, gram-negative bacterium transmitted by Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae. The bacterium is the presumed causal agent of huanglongbing (HLB, one of the most destructive and economically important diseases of citrus. We investigated whether Las is transmitted between infected and uninfected D. citri adults during courtship. Our results indicate that Las was sexually transmitted from Las-infected male D. citri to uninfected females at a low rate (<4% during mating. Sexual transmission was not observed following mating of infected females and uninfected males or among adult pairs of the same sex. Las was detected in genitalia of both sexes and also in eggs of infected females. A latent period of 7 days or more was required to detect the bacterium in recipient females. Rod shaped as well as spherical structures resembling Las were observed in ovaries of Las-infected females with transmission electron microscopy, but were absent in ovaries from uninfected D. citri females. The size of the rod shaped structures varied from 0.39 to 0.67 µm in length and 0.19 to 0.39 µm in width. The spherical structures measured from 0.61 to 0.80 µm in diameter. This investigation provides convincing evidence that a plant pathogenic bacterium is sexually transmitted from male to female insects during courtship and established evidence that bacteria persist in reproductive organs. Moreover, these findings provide an alternative sexually horizontal mechanism for the spread of Las within populations of D. citri, even in the absence of infected host trees.

Distribution of 'Candidatus Liberibacter asiaticus' Above and Below Ground in Texas Citrus.

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Louzada, Eliezer S; Vazquez, Omar Ed; Braswell, W Evan; Yanev, George; Devanaboina, Madhavi; Kunta, Madhurababu

2016-07-01

Detection of 'Candidatus Liberibacter asiaticus' represents one of the most difficult, yet critical, steps of controlling Huanglongbing disease. Efficient detection relies on understanding the underlying distribution of bacteria within trees. To that end, we studied the distribution of 'Ca. L. asiaticus' in leaves of 'Rio Red' grapefruit trees and in roots of 'Valencia' sweet orange trees grafted onto sour orange rootstock. We performed two sets of leaf collection on grapefruit trees; the first a selective sampling targeting symptomatic leaves and their neighbors and the second a systematic collection disregarding symptomology. From uprooted orange trees, we exhaustively sampled fibrous roots. In this study, the presence of 'Ca. L. asiaticus' was detected in leaves using real-time polymerase chain reaction (PCR) targeting the 16S ribosomal gene and in roots using the rpIJ/rpIL ribosomal protein genes and was confirmed with conventional PCR and sequencing of the rpIJ/rpIL gene in both tissues. Among randomly collected leaves, 'Ca. L. asiaticus' was distributed in a patchy fashion. Detection of 'Ca. L. asiaticus' varied with leaf symptomology with symptomatic leaves showing the highest frequency (74%) followed by their neighboring asymptomatic leaves (30%), while randomly distributed asymptomatic leaves had the lowest frequency (20%). Among symptomatic leaves, we found statistically significant differences in mean number of bacterial cells with respect to both increasing distance of the leaf from the trunk and cardinal direction. The titer of 'Ca. L. asiaticus' cells was significantly greater on the north side of trees than on the south and west sides. Moreover, these directions showed different spatial distributions of 'Ca. L. asiaticus' with higher titers near the trunk on the south and west sides as opposed to further from the trunk on the north side. Similarly, we found spatial variation in 'Ca. L. asiaticus' distribution among root samples. 'Ca. L. asiaticus

Development of a Tandem Repeat-Based Polymerase Chain Displacement Reaction Method for Highly Sensitive Detection of 'Candidatus Liberibacter asiaticus'.

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Lou, Binghai; Song, Yaqin; RoyChowdhury, Moytri; Deng, Chongling; Niu, Ying; Fan, Qijun; Tang, Yan; Zhou, Changyong

2018-02-01

Huanglongbing (HLB) is one of the most destructive diseases in citrus production worldwide. Early detection of HLB pathogens can facilitate timely removal of infected citrus trees in the field. However, low titer and uneven distribution of HLB pathogens in host plants make reliable detection challenging. Therefore, the development of effective detection methods with high sensitivity is imperative. This study reports the development of a novel method, tandem repeat-based polymerase chain displacement reaction (TR-PCDR), for the detection of 'Candidatus Liberibacter asiaticus', a widely distributed HLB-associated bacterium. A uniquely designed primer set (TR2-PCDR-F/TR2-PCDR-1R) and a thermostable Taq DNA polymerase mutant with strand displacement activity were used for TR-PCDR amplification. Performed in a regular thermal cycler, TR-PCDR could produce more than two amplicons after each amplification cycle. Sensitivity of the developed TR-PCDR was 10 copies of target DNA fragment. The sensitive level was proven to be 100× higher than conventional PCR and similar to real-time PCR. Data from the detection of 'Ca. L. asiaticus' with filed samples using the above three methods also showed similar results. No false-positive TR-PCDR amplification was observed from healthy citrus samples and water controls. These results thereby illustrated that the developed TR-PCDR method can be applied to the reliable, highly sensitive, and cost-effective detection of 'Ca. L. asiaticus'.

One Target, Two Mechanisms: The Impact of 'Candidatus Liberibacter asiaticus' and Its Vector, Diaphorina citri, on Citrus Leaf Pigments.

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Killiny, Nabil; Nehela, Yasser

2017-07-01

Huanglongbing (HLB) is currently the largest threat to global citrus production. We examined the effect of HLB pathogen 'Candidatus Liberibacter asiaticus' infection or infestation by its vector, Diaphorina citri, on 'Valencia' sweet orange leaf pigments using high-performance liquid chromatography, followed by gene expression analysis for 46 involved genes in carotenoid and chlorophyll biosynthesis pathways. Both 'Ca. L. asiaticus' and D. citri alter the total citrus leaf pigment balance with a greater impact by 'Ca. L. asiaticus'. Although zeaxanthin was accumulated in 'Ca. L. asiaticus'-infected leaves, chlorophyllide a was increased in D. citri-infested plants. Our findings support the idea that both 'Ca. L. asiaticus' and D. citri affect the citrus pigments and promote symptom development but using two different mechanisms. 'Ca. L. asiaticus' promotes chlorophyll degradation but accelerates the biosynthesis of carotenoid pigments, resulting in accumulation of abscisic acid and its precursor, zeaxanthin. Zeaxanthin also has a photoprotective role. By contrast, D. citri induced the degradation of most carotenoids and accelerated chlorophyll biosynthesis, leading to chlorophyllide a accumulation. Chlorophyllide a might have an antiherbivory role. Accordingly, we suggest that citrus plants try to defend themselves against 'Ca. L. asiaticus' or D. citri using multifaceted defense systems, based on the stressor type. These findings will help in better understanding the tritrophic interactions among plant, pathogen, and vector.

Genomic insights into the uncultured genus 'Candidatus Magnetobacterium' in the phylum Nitrospirae.

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Lin, Wei; Deng, Aihua; Wang, Zhang; Li, Ying; Wen, Tingyi; Wu, Long-Fei; Wu, Martin; Pan, Yongxin

2014-12-01

Magnetotactic bacteria (MTB) of the genus 'Candidatus Magnetobacterium' in phylum Nitrospirae are of great interest because of the formation of hundreds of bullet-shaped magnetite magnetosomes in multiple bundles of chains per cell. These bacteria are worldwide distributed in aquatic environments and have important roles in the biogeochemical cycles of iron and sulfur. However, except for a few short genomic fragments, no genome data are available for this ecologically important genus, and little is known about their metabolic capacity owing to the lack of pure cultures. Here we report the first draft genome sequence of 3.42 Mb from an uncultivated strain tentatively named 'Ca. Magnetobacterium casensis' isolated from Lake Miyun, China. The genome sequence indicates an autotrophic lifestyle using the Wood-Ljungdahl pathway for CO2 fixation, which has not been described in any previously known MTB or Nitrospirae organisms. Pathways involved in the denitrification, sulfur oxidation and sulfate reduction have been predicted, indicating its considerable capacity for adaptation to variable geochemical conditions and roles in local biogeochemical cycles. Moreover, we have identified a complete magnetosome gene island containing mam, mad and a set of novel genes (named as man genes) putatively responsible for the formation of bullet-shaped magnetite magnetosomes and the arrangement of multiple magnetosome chains. This first comprehensive genomic analysis sheds light on the physiology, ecology and biomineralization of the poorly understood 'Ca. Magnetobacterium' genus.

Development of a duplex droplet digital PCR assay for absolute quantitative detection of "Candidatus Liberibacter asiaticus".

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Selvaraj, Vijayanandraj; Maheshwari, Yogita; Hajeri, Subhas; Chen, Jianchi; McCollum, Thomas Greg; Yokomi, Raymond

2018-01-01

Huanglongbing (HLB, citrus greening) is a devastating citrus disease affecting citrus production worldwide. It is associated with the bacterium "Candidatus Liberibacter asiaticus" (CLas) and is vectored by the Asian citrus psyllid (ACP). Currently, diagnosis of CLas in regulatory samples is based on real-time quantitative polymerase chain reaction (qPCR) using 16S rRNA gene specific primers/probe. The detection of CLas using qPCR is challenging due to low pathogen titer and uneven distribution in infected plants and exacerbated by sampling issues and presence of inhibitors. This study evaluated a duplex droplet digital polymerase chain reaction (ddPCR) using multi-copy gene targets, 16S and RNR, to simultaneously detect CLas DNA targets in the same sample for unambiguous detection of the HLB pathogen in DNA extracts from citrus leaves and ACP. Standard curve analyses on tenfold dilution series with plasmid, citrus leaf and ACP DNA showed that both ddPCR and qPCR exhibited good linearity and efficiency in the duplex assay. CLas-infected low titer samples were used to validate the duplex ddPCR and qPCR performance and demonstrated that detection rate is higher when both 16S and RNR primers were used in duplex assay. However, the receiver operating characteristic analysis indicated that area under the curve for RNR primer was significantly broader, compared to 16S primers for CLas detection at low target titer. The absolute quantification of CLas at variable titers was reproducible and repeatable for both primer sets and the ddPCR showed higher resilience to PCR inhibitors with citrus leaf and ACP extracts. Hence, the resultant duplex ddPCR assay resulted in a significantly improved detection platform for diagnosis of CLas in samples with low pathogen titer.

Metabolic alterations in the nymphal instars of Diaphorina citri induced by Candidatus Liberibacter asiaticus, the putative pathogen of huanglongbing.

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Nabil Killiny

Full Text Available Currently, huanglongbing is the most damaging disease of citrus causing huge economic losses. The disease is caused by the Gram-negative bacterium Candidatus Liberibacter asiaticus (CLas. The pathogen is transmitted in a persistent propagative circulative manner within its vector, the Asian citrus psyllid, Diaphorina citri. Exploring the metabolic alteration in the vector may lead to a better understanding of the nutritional needs of CLas and to designing an artificial medium for culturing the pathogen. It has been shown that the nymphal stages have a greater role in transmission mainly because they feed on plants more actively than adults. In this study, we carried out an untargeted comparative metabolomic analysis for healthy and CLas-infected 4th / 5th instar nymphs. The metabolic analysis was performed using trimethylsilylation and methyl chloroformate derivatization followed by Gas Chromatography-Mass Spectrometry (GC-MS. Overall, the changes in the nymph metabolism due to the infection with CLas were more pronounced than in adults, as we previously published. Nymphs reared on CLas-infected Valencia sweet orange were higher in many metabolites, mainly those of the TCA cycle, C16 and C18 fatty acids, glucose, sucrose, L-proline, L-serine, pyroglutamic acid, saccharic acid, threonic acid and myo-inositol than those reared on healthy plants. In contrast, CLas-infected nymphs were lower in putrescine, glycine, L -phenylalanine, L -tyrosine, L -valine, and chiro-inositol. The information provided from this study may contribute in acceleration of the availability of CLas in culture and consequent screening of antibacterial compounds to discover a definitive solution for huanglongbing.

Better Together: Association With 'Candidatus Liberibacter Asiaticus' Increases the Reproductive Fitness of Its Insect Vector, Diaphorina citri (Hemiptera: Liviidae).

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Pelz-Stelinski, K S; Killiny, N

2016-05-01

The duration of the evolutionary association between a pathogen and vector can be inferred based on the strength of their mutualistic interactions. A well-adapted pathogen is likely to confer some benefit or, at a minimum, exhibit low pathogenicity toward its host vector. Coevolution of the two toward a mutually beneficial association appears to have occurred between the citrus greening disease pathogen, Candidatus Liberibacter asiaticus (Las), and its insect vector, the Asian citrus psyllid, Diaphorina citri (Kuwayama). To better understand the dynamics facilitating transmission, we evaluated the effects of Las infection on the fitness of its vector. Diaphorina citri harboring Las were more fecund than their uninfected counterparts; however, their nymphal development rate and adult survival were comparatively reduced. The finite rate of population increase and net reproductive rate were both greater among Las-infected D. citri as compared with uninfected counterparts, indicating that overall population fitness of infected psyllids was improved given the greater number of offspring produced. Previous reports of transovarial transmission, in conjunction with increased fecundity and population growth rates of Las-positive D. citri found in the current investigation, suggest a long evolutionary relationship between pathogen and vector. The survival of Las-infected adult D. citri was lower compared with uninfected D. citri , which suggests that there may be a fitness trade-off in response to Las infection. A beneficial effect of a plant pathogen on vector fitness may indicate that the pathogen developed a relationship with the insect before secondarily moving to plants.

Metabolic alterations in the nymphal instars of Diaphorina citri induced by Candidatus Liberibacter asiaticus, the putative pathogen of huanglongbing.

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Killiny, Nabil; Jones, Shelley E

2018-01-01

Currently, huanglongbing is the most damaging disease of citrus causing huge economic losses. The disease is caused by the Gram-negative bacterium Candidatus Liberibacter asiaticus (CLas). The pathogen is transmitted in a persistent propagative circulative manner within its vector, the Asian citrus psyllid, Diaphorina citri. Exploring the metabolic alteration in the vector may lead to a better understanding of the nutritional needs of CLas and to designing an artificial medium for culturing the pathogen. It has been shown that the nymphal stages have a greater role in transmission mainly because they feed on plants more actively than adults. In this study, we carried out an untargeted comparative metabolomic analysis for healthy and CLas-infected 4th / 5th instar nymphs. The metabolic analysis was performed using trimethylsilylation and methyl chloroformate derivatization followed by Gas Chromatography-Mass Spectrometry (GC-MS). Overall, the changes in the nymph metabolism due to the infection with CLas were more pronounced than in adults, as we previously published. Nymphs reared on CLas-infected Valencia sweet orange were higher in many metabolites, mainly those of the TCA cycle, C16 and C18 fatty acids, glucose, sucrose, L-proline, L-serine, pyroglutamic acid, saccharic acid, threonic acid and myo-inositol than those reared on healthy plants. In contrast, CLas-infected nymphs were lower in putrescine, glycine, L -phenylalanine, L -tyrosine, L -valine, and chiro-inositol. The information provided from this study may contribute in acceleration of the availability of CLas in culture and consequent screening of antibacterial compounds to discover a definitive solution for huanglongbing.

Metabolomic Response to Huanglongbing: Role of Carboxylic Compounds in Citrus sinensis Response to 'Candidatus Liberibacter asiaticus' and Its Vector, Diaphorina citri.

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Killiny, Nabil; Nehela, Yasser

2017-08-01

Huanglongbing, a destructive disease of citrus, is caused by the fastidious bacterium 'Candidatus Liberibacter asiaticus' and transmitted by Asian citrus psyllid, Diaphorina citri. The impact of 'Ca. L. asiaticus' infection or D. citri infestation on Valencia sweet orange (Citrus sinensis) leaf metabolites was investigated using gas chromatography mass spectrometry, followed by gene expression analysis for 37 genes involved in jasmonic acid (JA), salicylic acid (SA), and proline-glutamine pathways. The total amino acid abundance increased after 'Ca. L. asiaticus' infection, while the total fatty acids increased dramatically after infestation with D. citri, compared with control plants. Seven amino acids (glycine, l-isoleucine, l-phenylalanine, l-proline, l-serine, l-threonine, and l-tryptophan) and five organic acids (benzoic acid, citric acid, fumaric acid, SA, and succinic acid) increased in 'Ca. L. asiaticus'-infected plants. On the other hand, the abundance of trans-JA and its precursor α-linolenic increased in D. citri-infested plants. Surprisingly, the double attack of both D. citri infestation and 'Ca. L. asiaticus' infection moderated the metabolic changes in all chemical classes studied. In addition, the gene expression analysis supported these results. Based on these findings, we suggest that, although amino acids such as phenylalanine are involved in citrus defense against 'Ca. L. asiaticus' infection through the activation of an SA-mediated pathway, fatty acids, especially α-linolenic acid, are involved in defense against D. citri infestation via the induction of a JA-mediated pathway.

Better Together: Association With ‘Candidatus Liberibacter Asiaticus’ Increases the Reproductive Fitness of Its Insect Vector, Diaphorina citri (Hemiptera: Liviidae)

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Pelz-Stelinski, K. S.; Killiny, N.

2016-01-01

The duration of the evolutionary association between a pathogen and vector can be inferred based on the strength of their mutualistic interactions. A well-adapted pathogen is likely to confer some benefit or, at a minimum, exhibit low pathogenicity toward its host vector. Coevolution of the two toward a mutually beneficial association appears to have occurred between the citrus greening disease pathogen, Candidatus Liberibacter asiaticus (Las), and its insect vector, the Asian citrus psyllid, Diaphorina citri (Kuwayama). To better understand the dynamics facilitating transmission, we evaluated the effects of Las infection on the fitness of its vector. Diaphorina citri harboring Las were more fecund than their uninfected counterparts; however, their nymphal development rate and adult survival were comparatively reduced. The finite rate of population increase and net reproductive rate were both greater among Las-infected D. citri as compared with uninfected counterparts, indicating that overall population fitness of infected psyllids was improved given the greater number of offspring produced. Previous reports of transovarial transmission, in conjunction with increased fecundity and population growth rates of Las-positive D. citri found in the current investigation, suggest a long evolutionary relationship between pathogen and vector. The survival of Las-infected adult D. citri was lower compared with uninfected D. citri, which suggests that there may be a fitness trade-off in response to Las infection. A beneficial effect of a plant pathogen on vector fitness may indicate that the pathogen developed a relationship with the insect before secondarily moving to plants. PMID:27418697

Phenology of the Potato Psyllid, Bactericera cockerelli (Hemiptera: Triozidae), and "Candidatus Liberibacter solanacearum" in Commercial Potato Fields in Idaho.

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Wenninger, Erik J; Carroll, Amy; Dahan, Jennifer; Karasev, Alexander V; Thornton, Michael; Miller, Jeff; Nolte, Philip; Olsen, Nora; Price, William

2017-12-08

Zebra chip disease (ZC) is an emerging disease of potato in which tubers are produced with striped necrotic patterns that make them unmarketable. ZC is associated with the bacterium "Candidatus Liberibacter solanacearum" (Lso), which is transmitted by the potato psyllid, Bactericera cockerelli (Šulc; Hemiptera: Triozidae). First found in Idaho during 2011, ZC now contributes to increased production costs each season via additional insecticide sprays. To clarify the extent and severity of the threat of ZC in Idaho, we sampled potato psyllids in commercial potato fields across the state over four growing seasons (2012-2015). All life stages of psyllids were sampled using a combination of methods (yellow sticky traps, vacuum samples, and leaf samples), and adult psyllids were tested for the presence of Lso by Polymerase Chain Reaction (PCR). Abundance of potato psyllids initially increased gradually over each growing season, then exhibited a sharp late-season rise and a sharp decline as most fields were being harvested. Abundance of psyllids was higher at warmer, lower elevation sites, but infestation onset did not differ between growing regions. Fewer psyllids were collected in vacuum samples than in sticky trap samples. Nymphs and eggs were found only late season and during years with high abundance of adults. Overall incidence of Lso was similar among all years but one. The results presented here clarify our understanding of the seasonal phenology of potato psyllids and Lso in Idaho potato fields and will aid in developing integrated management strategies against this important pest of potato. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

An HPLC-MS characterization of the changes in sweet orange leaf metabolite profile following infection by the bacterial pathogen Candidatus Liberibacter asiaticus.

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Hijaz, Faraj M; Manthey, John A; Folimonova, Svetlana Y; Davis, Craig L; Jones, Shelley E; Reyes-De-Corcuera, José I

2013-01-01

Huanglongbing (HLB) presumably caused by Candidatus Liberibacter asiaticus (CLas) threatens the commercial U.S. citrus crop of an annual value of $3 billion. The earliest shift in metabolite profiles of leaves from greenhouse-grown sweet orange trees infected with Clas, and of healthy leaves, was characterized by HPLC-MS concurrently with PCR testing for the presence of Clas bacteria and observation of disease symptoms. Twenty, 8-month-old 'Valencia' and 'Hamlin' trees were grafted with budwood from PCR-positive HLB source trees. Five graft-inoculated trees of each variety and three control trees were sampled biweekly and analyzed by HPLC-MS and PCR. Thirteen weeks after inoculation, Clas was detected in newly growing flushes in 33% and 55% of the inoculated 'Hamlin' and 'Valencia' trees, respectively. Inoculated trees remained asymptomatic in the first 20 weeks, but developed symptoms 30 weeks after grafting. No significant differences in the leaf metabolite profiles were detected in Clas-infected trees 23 weeks after inoculation. However, 27 weeks after inoculation, differences in metabolite profiles between control leaves and those of Clas-infected trees were evident. Affected compounds were identified with authentic standards or structurally classified by their UV and mass spectra. Included among these compounds are flavonoid glycosides, polymethoxylated flavones, and hydroxycinnamates. Four structurally related hydroxycinnamate compounds increased more than 10-fold in leaves from 'Hamlin' and 'Valencia' sweet orange trees in response to Clas infection. Possible roles of these hydroxycinnamates as plant defense compounds against the Clas infection are discussed.

The phloem-sap feeding mealybug (Ferrisia virgata carries 'Candidatus Liberibacter asiaticus' populations that do not cause disease in host plants.

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Marco Pitino

Full Text Available 'Candidatus Liberibacter asiaticus' (Las is the primary causal agent of huanglongbing (HLB, the most devastating disease of citrus worldwide. There are three known insect vectors of the HLB-associated bacteria, and all are members of the Hemiptera: Diaphorina citri (Psyllidae, Trioza erytreae (Triozidae, and Cacopsylla (Psylla citrisuga (Psyllidae. In this study, we found that another hemipteran, the striped mealybug Ferrisia virgata (Cockerell (Hemiptera: Pseudococcidae, was able to acquire and retain Las bacteria. The bacterial titers were positively correlated with the feeding acquisition time on Las-infected leaf discs, with a two-weeks feeding period resulting in Ct values ranging from 23.1 to 36.1 (8.24 × 10(7 to 1.07 × 10(4 Las cells per mealybug. We further discovered that the prophage/phage populations of Las in the mealybugs were different from those of Las in psyllids based on Las prophage-specific molecular markers: infected psyllids harbored the Las populations with prophage/phage FP1 and FP2, while infected mealybugs carried the Las populations with the iFP3 being the dominant prophage/phage. As in the psyllids, Las bacteria were shown to move through the insect gut wall to the salivary glands after being ingested by the mealybug based on a time-course quantitative polymerase chain reaction (qPCR assay of the dissected digestive systems. However, Las populations transmitted by the mealybugs did not cause disease in host plants. This is the first evidence of genetic difference among Las populations harbored by different insect vectors and difference among Las populations with respect to whether or not they cause disease in host plants.

Contrasting amino acid profiles among permissive and non-permissive hosts of Candidatus Liberibacter asiaticus, putative causal agent of Huanglongbing.

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Mamoudou Sétamou

Full Text Available Huanglongbing is a devastating disease of citrus. In this study, a comprehensive profile of phloem sap amino acids (AA in four permissive host plants of Candidatus Liberibacter asiaticus (CLas and three non-permissive Rutaceae plants was conducted to gain a better understanding of host factors that may promote or suppress the bacterium. The AA profiles of Diaphorina citri nymphs and adults were similarly analyzed. A total of 38 unique AAs were detected in phloem sap of the various plants and D. citri samples, with phloem sap of young shoots containing more AAs and at higher concentrations than their mature counterparts. All AAs detected in phloem sap of non-permissive plants were also present in CLas -permissive hosts plus additional AAs in the latter class of plants. However, the relative composition of 18 commonly shared AAs varied between CLas -permissive hosts and non-permissive plants. Multivariate analysis with a partial least square discriminant methodology revealed a total of 12 AAs as major factors affecting CLas host status, of which seven were positively related to CLas tolerance/resistance and five positively associated with CLas susceptibility. Most of the AAs positively associated with CLas susceptibility were predominantly of the glutamate family, notably stressed-induced AAs such as arginine, GABA and proline. In contrast, AAs positively correlated with CLas tolerance/resistance were mainly of the serine family. Further analysis revealed that whereas the relative proportions of AAs positively associated with CLas susceptibility did not vary with host developmental stages, those associated with CLas tolerance/resistance increased with flush shoot maturity. Significantly, the proline-to-glycine ratio was determined to be an important discriminating factor for CLas permissivity with higher values characteristic of CLas -permissive hosts. This ratio could be exploited as a biomarker in HLB-resistance breeding programs.

Disentangling the Taxonomy of Rickettsiales and Description of Two Novel Symbionts ("Candidatus Bealeia paramacronuclearis" and "Candidatus Fokinia cryptica") Sharing the Cytoplasm of the Ciliate Protist Paramecium biaurelia.

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Szokoli, Franziska; Castelli, Michele; Sabaneyeva, Elena; Schrallhammer, Martina; Krenek, Sascha; Doak, Thomas G; Berendonk, Thomas U; Petroni, Giulio

2016-12-15

inhabiting the same Paramecium host (Ciliophora, Alveolata). Both symbionts belong to "traditional" Rickettsiales, one representing a new species of the genus "Candidatus Fokinia" ("Candidatus Midichloriaceae"), and the other representing a new genus of a "basal" Rickettsiales According to newly characterized sequences and to a critical revision of recent literature, we propose a taxonomic reorganization of "traditional" Rickettsiales that we split into two orders: Rickettsiales sensu stricto and Holosporales ord. nov. This work represents a critical revision, including new records of a group of symbionts frequently occurring in protists and whose biodiversity is still largely underestimated. Copyright © 2016 Szokoli et al.

Susceptibilities of Candidatus Liberibacter asiaticus-infected and noninfected Diaphorina citri to entomopathogenic fungi and their detoxification enzyme activities under different temperatures.

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Hussain, Mubasher; Akutse, Komivi Senyo; Lin, Yongwen; Chen, Shiman; Huang, Wei; Zhang, Jinguan; Idrees, Atif; Qiu, Dongliang; Wang, Liande

2018-03-25

Some entomopathogenic fungi species, Isaria fumosorosea, and Hirsutella citriformis were found to be efficient against the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae). However, the susceptibility to these fungi increases when the psyllid infected with Candidatus Liberibacter asiaticus (Las), which is transmitted by D. citri and causes citrus greening disease. In this study, we examined the Las-infected and Las-uninfected D. citri susceptibility to entomopathogenic fungi at different temperature regimes (5-40°C). When D. citri adults exposed to cold temperature (5°C), they showed less susceptibility to entomopathogenic fungi as compared with control (27°C). Irrespective of infection with Las, a significantly positive correlation was observed between temperature and percentage mortality caused by different isolates of I. fumosorosea, 3A Ifr, 5F Ifr, PS Ifr, and H. citriformis isolates, HC3D and 2H. In contrast, a significantly negative correlation was found between temperature and percentage mortality for 3A Ifr for both Las-infected and Las-uninfected psyllids. Detoxification enzymes, Glutathione S-transferase levels in D. citri showed a negative correlation, whereas cytochrome P450 and general esterase levels were not correlated with changes in temperature. These findings revealed that detoxification enzymes and general esterase levels are not correlated with altered susceptibility to entomopathogenic fungi at the different temperature regimes. Conclusively, temperature fluctuations tested appear to be a significant factor impacting the management strategies of D. citri using entomopathogenic fungi. © 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Comparison of Potato and Asian Citrus Psyllid Adult and Nymph Transcriptomes Identified Vector Transcripts with Potential Involvement in Circulative, Propagative Liberibacter Transmission

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Tonja W. Fisher

2014-11-01

Full Text Available The potato psyllid (PoP Bactericera cockerelli (Sulc and Asian citrus psyllid (ACP Diaphorina citri Kuwayama are the insect vectors of the fastidious plant pathogen, Candidatus Liberibacter solanacearum (CLso and Ca. L. asiaticus (CLas, respectively. CLso causes Zebra chip disease of potato and vein-greening in solanaceous species, whereas, CLas causes citrus greening disease. The reliance on insecticides for vector management to reduce pathogen transmission has increased interest in alternative approaches, including RNA interference to abate expression of genes essential for psyllid-mediated Ca. Liberibacter transmission. To identify genes with significantly altered expression at different life stages and conditions of CLso/CLas infection, cDNA libraries were constructed for CLso-infected and -uninfected PoP adults and nymphal instars. Illumina sequencing produced 199,081,451 reads that were assembled into 82,224 unique transcripts. PoP and the analogous transcripts from ACP adult and nymphs reported elsewhere were annotated, organized into functional gene groups using the Gene Ontology classification system, and analyzed for differential in silico expression. Expression profiles revealed vector life stage differences and differential gene expression associated with Liberibacter infection of the psyllid host, including invasion, immune system modulation, nutrition, and development.

Predominance of Single Prophage Carrying a CRISPR/cas System in “Candidatus Liberibacter asiaticus” Strains in Southern China

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Zheng, Zheng; Bao, Minli; Wu, Fengnian; Chen, Jianchi; Deng, Xiaoling

2016-01-01

“Candidatus Liberibacter asiaticus” (CLas) is an uncultureable α-proteobacterium associated with citrus Huanglongbing (HLB, yellow shoot disease), a highly destructive disease affecting citrus production worldwide. HLB was observed in Guangdong Province of China over a hundred years ago and remains endemic there. Little is known about CLas biology due to its uncultureable nature. This study began with the genome sequence analysis of CLas Strain A4 from Guangdong in the prophage region. Within the two currently known prophage types, Type 1 (SC1-like) and Type 2 (SC2-like), A4 genome contained only a Type 2 prophage, CGdP2, namely. An analysis on CLas strains collected in Guangdong showed that Type 2 prophage dominated the bacterial population (82.6%, 71/86). An extended survey covering five provinces in southern China also revealed the predominance of single prophage (Type 1 or Type 2) in the CLas population (90.4%, 169/187). CLas strains with two and no prophage types accounted for 7.2% and 2.8%, respectively. In silico analyses on CGdP2 identified a CRISPR (clustered regularly interspaced short palindromic repeats)/cas (CRISPR-associated protein genes) system, consisting of four 22 bp repeats, three 23 bp spacers and 9 predicted cas. Similar CRISPR/cas systems were detected in all 10 published CLas prophages as well as 13 CLas field strains in southern China. Both Type 1 and Type 2 prophages shared almost identical sequences in spacer 1 and 3 but not spacer 2. Considering that the function of a CRISPR/cas system was to destroy invading DNA, it was hypothesized that a pre-established CLas prophage could use its CRISPR/cas system guided by spacer 1 and/or 3 to defeat the invasion of the other phage/prophage. This hypothesis explained the predominance of single prophage type in the CLas population in southern China. This is the first report of CRISPR/cas system in the “Ca. Liberibacter” genera. PMID:26741827

Molecular and physiological properties associated with zebra complex disease in potatoes and its relation with Candidatus Liberibacter contents in psyllid vectors.

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Veria Y Alvarado

Full Text Available Zebra complex (ZC disease on potatoes is associated with Candidatus Liberibacter solanacearum (CLs, an α-proteobacterium that resides in the plant phloem and is transmitted by the potato psyllid Bactericera cockerelli (Šulc. The name ZC originates from the brown striping in fried chips of infected tubers, but the whole plants also exhibit a variety of morphological features and symptoms for which the physiological or molecular basis are not understood. We determined that compared to healthy plants, stems of ZC-plants accumulate starch and more than three-fold total protein, including gene expression regulatory factors (e.g. cyclophilin and tuber storage proteins (e.g., patatins, indicating that ZC-affected stems are reprogrammed to exhibit tuber-like physiological properties. Furthermore, the total phenolic content in ZC potato stems was elevated two-fold, and amounts of polyphenol oxidase enzyme were also high, both serving to explain the ZC-hallmark rapid brown discoloration of air-exposed damaged tissue. Newly developed quantitative and/or conventional PCR demonstrated that the percentage of psyllids in laboratory colonies containing detectable levels of CLs and its titer could fluctuate over time with effects on colony prolificacy, but presumed reproduction-associated primary endosymbiont levels remained stable. Potato plants exposed in the laboratory to psyllid populations with relatively low-CLs content survived while exposure of plants to high-CLs psyllids rapidly culminated in a lethal collapse. In conclusion, we identified plant physiological biomarkers associated with the presence of ZC and/or CLs in the vegetative potato plant tissue and determined that the titer of CLs in the psyllid population directly affects the rate of disease development in plants.

Molecular and Physiological Properties Associated with Zebra Complex Disease in Potatoes and Its Relation with Candidatus Liberibacter Contents in Psyllid Vectors

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Alvarado, Veria Y.; Odokonyero, Denis; Duncan, Olivia; Mirkov, T. Erik; Scholthof, Herman B.

2012-01-01

Zebra complex (ZC) disease on potatoes is associated with Candidatus Liberibacter solanacearum (CLs), an α-proteobacterium that resides in the plant phloem and is transmitted by the potato psyllid Bactericera cockerelli (Šulc). The name ZC originates from the brown striping in fried chips of infected tubers, but the whole plants also exhibit a variety of morphological features and symptoms for which the physiological or molecular basis are not understood. We determined that compared to healthy plants, stems of ZC-plants accumulate starch and more than three-fold total protein, including gene expression regulatory factors (e.g. cyclophilin) and tuber storage proteins (e.g., patatins), indicating that ZC-affected stems are reprogrammed to exhibit tuber-like physiological properties. Furthermore, the total phenolic content in ZC potato stems was elevated two-fold, and amounts of polyphenol oxidase enzyme were also high, both serving to explain the ZC-hallmark rapid brown discoloration of air-exposed damaged tissue. Newly developed quantitative and/or conventional PCR demonstrated that the percentage of psyllids in laboratory colonies containing detectable levels of CLs and its titer could fluctuate over time with effects on colony prolificacy, but presumed reproduction-associated primary endosymbiont levels remained stable. Potato plants exposed in the laboratory to psyllid populations with relatively low-CLs content survived while exposure of plants to high-CLs psyllids rapidly culminated in a lethal collapse. In conclusion, we identified plant physiological biomarkers associated with the presence of ZC and/or CLs in the vegetative potato plant tissue and determined that the titer of CLs in the psyllid population directly affects the rate of disease development in plants. PMID:22615987

Asian Citrus Psyllid Expression Profiles Suggest Candidatus Liberibacter Asiaticus-Mediated Alteration of Adult Nutrition and Metabolism, and of Nymphal Development and Immunity.

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Meenal Vyas

Full Text Available The Asian citrus psyllid (ACP Diaphorina citri Kuwayama (Hemiptera: Psyllidae is the insect vector of the fastidious bacterium Candidatus Liberibacter asiaticus (CLas, the causal agent of citrus greening disease, or Huanglongbing (HLB. The widespread invasiveness of the psyllid vector and HLB in citrus trees worldwide has underscored the need for non-traditional approaches to manage the disease. One tenable solution is through the deployment of RNA interference technology to silence protein-protein interactions essential for ACP-mediated CLas invasion and transmission. To identify psyllid interactor-bacterial effector combinations associated with psyllid-CLas interactions, cDNA libraries were constructed from CLas-infected and CLas-free ACP adults and nymphs, and analyzed for differential expression. Library assemblies comprised 24,039,255 reads and yielded 45,976 consensus contigs. They were annotated (UniProt, classified using Gene Ontology, and subjected to in silico expression analyses using the Transcriptome Computational Workbench (TCW (http://www.sohomoptera.org/ACPPoP/. Functional-biological pathway interpretations were carried out using the Kyoto Encyclopedia of Genes and Genomes databases. Differentially expressed contigs in adults and/or nymphs represented genes and/or metabolic/pathogenesis pathways involved in adhesion, biofilm formation, development-related, immunity, nutrition, stress, and virulence. Notably, contigs involved in gene silencing and transposon-related responses were documented in a psyllid for the first time. This is the first comparative transcriptomic analysis of ACP adults and nymphs infected and uninfected with CLas. The results provide key initial insights into host-parasite interactions involving CLas effectors that contribute to invasion-virulence, and to host nutritional exploitation and immune-related responses that appear to be essential for successful ACP-mediated circulative, propagative CLas

Disentangling the Taxonomy of Rickettsiales and Description of Two Novel Symbionts (“Candidatus Bealeia paramacronuclearis” and “Candidatus Fokinia cryptica”) Sharing the Cytoplasm of the Ciliate Protist Paramecium biaurelia

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Szokoli, Franziska; Castelli, Michele; Sabaneyeva, Elena; Schrallhammer, Martina; Krenek, Sascha; Doak, Thomas G.; Berendonk, Thomas U.

2016-01-01

characterization of two novel bacterial symbionts inhabiting the same Paramecium host (Ciliophora, Alveolata). Both symbionts belong to “traditional” Rickettsiales, one representing a new species of the genus “Candidatus Fokinia” (“Candidatus Midichloriaceae”), and the other representing a new genus of a “basal” Rickettsiales. According to newly characterized sequences and to a critical revision of recent literature, we propose a taxonomic reorganization of “traditional” Rickettsiales that we split into two orders: Rickettsiales sensu stricto and Holosporales ord. nov. This work represents a critical revision, including new records of a group of symbionts frequently occurring in protists and whose biodiversity is still largely underestimated. PMID:27742680

Combining 'omics and microscopy to visualize interactions between the Asian citrus psyllid vector and the Huanglongbing pathogen Candidatus Liberibacter asiaticus in the insect gut.

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Angela Kruse

Full Text Available Huanglongbing, or citrus greening disease, is an economically devastating bacterial disease of citrus. It is associated with infection by the gram-negative bacterium Candidatus Liberibacter asiaticus (CLas. CLas is transmitted by Diaphorina citri, the Asian citrus psyllid (ACP. For insect transmission to occur, CLas must be ingested during feeding on infected phloem sap and cross the gut barrier to gain entry into the insect vector. To investigate the effects of CLas exposure at the gut-pathogen interface, we performed RNAseq and mass spectrometry-based proteomics to analyze the transcriptome and proteome, respectively, of ACP gut tissue. CLas exposure resulted in changes in pathways involving the TCA cycle, iron metabolism, insecticide resistance and the insect's immune system. We identified 83 long non-coding RNAs that are responsive to CLas, two of which appear to be specific to the ACP. Proteomics analysis also enabled us to determine that Wolbachia, a symbiont of the ACP, undergoes proteome regulation when CLas is present. Fluorescent in situ hybridization (FISH confirmed that Wolbachia and CLas inhabit the same ACP gut cells, but do not co-localize within those cells. Wolbachia cells are prevalent throughout the gut epithelial cell cytoplasm, and Wolbachia titer is more variable in the guts of CLas exposed insects. CLas is detected on the luminal membrane, in puncta within the gut epithelial cell cytoplasm, along actin filaments in the gut visceral muscles, and rarely, in association with gut cell nuclei. Our study provides a snapshot of how the psyllid gut copes with CLas exposure and provides information on pathways and proteins for targeted disruption of CLas-vector interactions at the gut interface.

The effect of 'Candidatus Liberibacter asiaticus' infection on the proteomic profiles and nutritional status of pre-symptomatic and symptomatic grapefruit (Citrus paradisi) plants.

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Nwugo, Chika C; Lin, Hong; Duan, Yongping; Civerolo, Edwin L

2013-04-11

Huanglongbing (HLB) is a highly destructive citrus disease which threatens citrus production worldwide and 'Candidatus Liberibacter asiaticus' (Las), a non-culturable phloem-limited bacterium, is an associated causal agent of the disease. To better understand the physiological and molecular processes involved in host responses to Las, 2-DE and mass spectrometry analyses, as well as ICP spectroscopy analysis were employed to elucidate the global protein expression profiles and nutrient concentrations in leaves of Las-infected grapefruit plants at pre-symptomatic or symptomatic stages for HLB. This study identified 123 protein spots out of 191 spots that showed significant changes in the leaves of grapefruit plants in response to Las infection and all identified spots matched to 69 unique proteins/peptides. A down-regulation of 56 proteins including those associated with photosynthesis, protein synthesis, and metabolism was correlated with significant reductions in the concentrations of Ca, Mg, Fe, Zn, Mn, and Cu in leaves of grapefruit plants in response to Las infection, particularly in symptomatic plants. Oxygen-evolving enhancer (OEE) proteins, a PSI 9 kDa protein, and a Btf3-like protein were among a small group of proteins that were down-regulated in both pre-symptomatic and symptomatic plants in response to Las infection. Furthermore, a Las-mediated up-regulation of 13 grapefruit proteins was detected, which included Cu/Zn superoxide dismutase, chitinases, lectin-related proteins, miraculin-like proteins, peroxiredoxins and a CAP 160 protein. Interestingly, a Las-mediated up-regulation of granule-bound starch synthase was correlated with an increase in the K concentrations of pre-symptomatic and symptomatic plants. This study constitutes the first attempt to characterize the interrelationships between protein expression and nutritional status of Las-infected pre-symptomatic or symptomatic grapefruit plants and sheds light on the physiological and molecular

Enhanced Acquisition Rates of 'Candidatus Liberibacter asiaticus' by the Asian Citrus Psyllid (Hemiptera: Liviidae) in the Presence of Vegetative Flush Growth in Citrus.

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Sétamou, Mamoudou; Alabi, Olufemi J; Kunta, Madhurababu; Jifon, John L; da Graça, John V

2016-10-01

The Asian citrus psyllid preferentially feeds and exclusively reproduces on young, newly emerged flush shoots of citrus. Asian citrus psyllid nymphs feed and complete their life stages on these flush shoots. Recent studies conducted under greenhouse conditions have shown that the transmission rates of 'Candidatus Liberibacter asiaticus' (CLas), the putative causal agent of huanglongbing disease of citrus, are enhanced when flush shoots are present. However, it is unclear if CLas acquisition by migrant adult Asian citrus psyllids is similarly enhanced. To address this knowledge gap, cohorts of Asian citrus psyllid adults were allowed 1-wk acquisition access period (AAP) on flushing and nonflushing shoots of qPCR-tested symptomatic (CLas+) and asymptomatic (CLas-) 10-yr-old sweet orange trees under field conditions. After the AAP, they were tested for CLas by qPCR. Progeny Asian citrus psyllid adults that emerged 4 wk post-AAP were similarly retrieved and tested. Eighty percent of flushing and 30% of nonflushing CLas+ trees produced infective Asian citrus psyllid adults, indicating that flush shoots have greater potential to be inoculum sources for CLas acquisition. Concomitantly, 21.1% and 6.0% infective adults were retrieved, respectively, from flushing and nonflushing CLas+ trees, indicating that Asian citrus psyllid adults acquire CLas more efficiently from flush shoots relative to mature shoots. In addition, 12.1% of infective Asian citrus psyllid adult progeny were obtained from 70% of flushing CLas+ trees. Significantly lower mean Ct values were also obtained from infective adults retrieved from flushing relative to nonflushing trees. The results underscore the role of flush shoots in CLas acquisition and the need to protect citrus trees from Asian citrus psyllid infestations during flush cycles. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email

Use of Electrical Penetration Graph Technology to Examine Transmission of 'Candidatus Liberibacter solanacearum' to Potato by Three Haplotypes of Potato Psyllid (Bactericera cockerelli; Hemiptera: Triozidae.

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Tariq Mustafa

Full Text Available The potato psyllid, Bactericera cockerelli (Šulc (Hemiptera: Triozidae, is a vector of the phloem-limited bacterium 'Candidatus Liberibacter solanacearum' (Lso, the putative causal agent of zebra chip disease of potato. Little is known about how potato psyllid transmits Lso to potato. We used electrical penetration graph (EPG technology to compare stylet probing behaviors and efficiency of Lso transmission of three haplotypes of potato psyllid (Central, Western, Northwestern. All haplotypes exhibited the full suite of stylet behaviors identified in previous studies with this psyllid, including intercellular penetration and secretion of the stylet pathway, xylem ingestion, and phloem activities, the latter comprising salivation and ingestion. The three haplotypes exhibited similar frequency and duration of probing behaviors, with the exception of salivation into phloem, which was of higher duration by psyllids of the Western haplotype. We manipulated how long psyllids were allowed access to potato ("inoculation access period", or IAP to examine the relationship between phloem activities and Lso transmission. Between 25 and 30% of psyllids reached and salivated into phloem at an IAP of 1 hr, increasing to almost 80% of psyllids as IAP was increased to 24 h. Probability of Lso-transmission was lower across all IAP levels than probability of phloem salivation, indicating that a percentage of infected psyllids which salivated into the phloem failed to transmit Lso. Logistic regression showed that probability of transmission increased as a function of time spent salivating into the phloem; transmission occurred as quickly as 5 min following onset of salivation. A small percentage of infected psyllids showed extremely long salivation events but nonetheless failed to transmit Lso, for unknown reasons. Information from these studies increases our understanding of Lso transmission by potato psyllid, and demonstrates the value of EPG technology in

Genome and metabolic network of Candidatus Phaeomarinobacter ectocarpi Ec32, a new candidate genus of Alphaproteobacteria frequently associated with brown algae

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Simon M Dittami

2014-07-01

Full Text Available Rhizobiales and related orders of Alphaproteobacteria comprise several genera of nodule-inducing symbiotic bacteria associated with plant roots. Here we describe the genome and the metabolic network of Candidatus Phaeomarinobacter ectocarpi Ec32, a member of a new candidate genus closely related to Rhizobiales and found in association with cultures of the filamentous brown algal model Ectocarpus. The Ca. P. ectocarpi genome encodes numerous metabolic pathways that may be relevant for this bacterium to interact with algae. Notably, it possesses a large set of glycoside hydrolases and transporters, which may serve to process and assimilate algal metabolites. It also harbors several proteins likely to be involved in the synthesis of algal hormones such as auxins and cytokinins, as well as the vitamins pyridoxine, biotin, and thiamine. As of today, Ca. P. ectocarpi has not been successfully cultured, and identical 16S rDNA sequences have been found exclusively associated with Ectocarpus. However, related sequences (≥ 97% identity have also been detected free-living and in a Fucus vesiculosus microbiome barcoding project, indicating that the candidate genus Phaeomarinobacter may comprise several species, which may colonize different niches.

Transcriptome analysis of sweet orange trees infected with 'Candidatus Liberibacter asiaticus' and two strains of Citrus Tristeza Virus.

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Fu, Shimin; Shao, Jonathan; Zhou, Changyong; Hartung, John S

2016-05-11

Huanglongbing (HLB) and tristeza, are diseases of citrus caused by a member of the α-proteobacteria, 'Candidatus Liberibacter asiaticus' (CaLas), and Citrus tristeza virus (CTV) respectively. HLB is a devastating disease, but CTV strains vary from very severe to very mild. Both CaLas and CTV are phloem-restricted. The CaLas-B232 strain and CTV-B6 cause a wide range of severe and similar symptoms. The mild strain CTV-B2 doesn't induce significant symptoms or damage to plants. Transcriptome profiles obtained through RNA-seq revealed 611, 404 and 285 differentially expressed transcripts (DETs) after infection with CaLas-B232, CTV-B6 and CTV-B2. These DETs were components of a wide range of pathways involved in circadian rhythm, cell wall modification and cell organization, as well as transcription factors, transport, hormone response and secondary metabolism, signaling and stress response. The number of transcripts that responded to both CTV-B6 and CaLas-B232 was much larger than the number of transcripts that responded to both strains of CTV or to both CTV-B2 and CaLas-B232. A total of 38 genes were assayed by RT-qPCR and the correlation coefficients between Gfold and RT-qPCR were 0.82, 0.69, 0.81 for sweet orange plants infected with CTV-B2, CTV-B6 and CaLas-B232, respectively. The number and composition of DETs reflected the complexity of symptoms caused by the pathogens in established infections, although the leaf tissues sampled were asymptomatic. There were greater similarities between the sweet orange in response to CTV-B6 and CaLas-B232 than between the two CTV strains, reflecting the similar physiological changes caused by both CTV-B6 and CaLas-B232. The circadian rhythm system of plants was perturbed by all three pathogens, especially by CTV-B6, and the ion balance was also disrupted by all three pathogens, especially by CaLas-B232. Defense responses related to cell wall modification, transcriptional regulation, hormones, secondary metabolites, kinases and

'Candidatus Pasteuria aldrichii', an obligate endoparasite of the bacterivorous nematode Bursilla.

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Giblin-Davis, R M; Nong, G; Preston, J F; Williams, D S; Center, B J; Brito, J A; Dickson, D W

2011-09-01

A novel bacterium of the genus Pasteuria was discovered parasitizing bacterivorous nematodes of the genus Bursilla, in selected bermudagrass (Cynodon) field plots in Davie, FL, USA. Soil containing this bacterium was sampled and supplied with bi-weekly inoculations of cultured species of the genus Bursilla in order to build and maintain a source of endospores for continuous in vivo conservation of the bacteria for further study and characterization. 16S rRNA gene sequence similarities supported its congeneric ranking with other members of the genus Pasteuria that have been identified from nematodes and cladocerans. There were, however, no clear sister candidates for this organism, which supported the evidence of endospore ultrastructure and host-range studies, suggesting it belonged to a novel taxon. Because members of the genus Pasteuria cannot yet be isolated, definitive type strains could not be maintained; therefore, the name 'Candidatus Pasteuria aldrichii' is proposed for this organism.

Use of Electrical Penetration Graph Technology to Examine Transmission of ‘Candidatus Liberibacter solanacearum’ to Potato by Three Haplotypes of Potato Psyllid (Bactericera cockerelli; Hemiptera: Triozidae)

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Mustafa, Tariq; Horton, David R.; Cooper, W. Rodney; Swisher, Kylie D.; Zack, Richard S.; Pappu, Hanu R.; Munyaneza, Joseph E.

2015-01-01

The potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae), is a vector of the phloem-limited bacterium ‘Candidatus Liberibacter solanacearum’ (Lso), the putative causal agent of zebra chip disease of potato. Little is known about how potato psyllid transmits Lso to potato. We used electrical penetration graph (EPG) technology to compare stylet probing behaviors and efficiency of Lso transmission of three haplotypes of potato psyllid (Central, Western, Northwestern). All haplotypes exhibited the full suite of stylet behaviors identified in previous studies with this psyllid, including intercellular penetration and secretion of the stylet pathway, xylem ingestion, and phloem activities, the latter comprising salivation and ingestion. The three haplotypes exhibited similar frequency and duration of probing behaviors, with the exception of salivation into phloem, which was of higher duration by psyllids of the Western haplotype. We manipulated how long psyllids were allowed access to potato (“inoculation access period”, or IAP) to examine the relationship between phloem activities and Lso transmission. Between 25 and 30% of psyllids reached and salivated into phloem at an IAP of 1 hr, increasing to almost 80% of psyllids as IAP was increased to 24 h. Probability of Lso-transmission was lower across all IAP levels than probability of phloem salivation, indicating that a percentage of infected psyllids which salivated into the phloem failed to transmit Lso. Logistic regression showed that probability of transmission increased as a function of time spent salivating into the phloem; transmission occurred as quickly as 5 min following onset of salivation. A small percentage of infected psyllids showed extremely long salivation events but nonetheless failed to transmit Lso, for unknown reasons. Information from these studies increases our understanding of Lso transmission by potato psyllid, and demonstrates the value of EPG technology in exploring

Transcriptional analysis of sweet orange trees co-infected with 'Candidatus Liberibacter asiaticus' and mild or severe strains of Citrus tristeza virus.

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Fu, Shimin; Shao, Jonathan; Paul, Cristina; Zhou, Changyong; Hartung, John S

2017-10-31

Citrus worldwide is threatened by huanglongbing (HLB) and tristeza diseases caused by 'Candidatus Liberibacter asiaticus' (CaLas) and Citrus tristeza virus (CTV). Although the pathogens are members of the α-proteobacteria and Closteroviridae, respectively, both are restricted to phloem cells in infected citrus and are transmitted by insect vectors. The response of sweet orange to single infection by either of these two pathogens has been characterized previously by global gene expression analysis. But because of the ubiquity of these pathogens where the diseases occur, co-infection by both pathogens is very common and could lead to increased disease severity based on synergism. We therefore co-inoculated sweet orange trees with CaLas and either a mild or a severe strain of CTV, and measured changes of gene expression in host plants. In plants infected with CaLas-B232, the overall alteration in gene expression was much greater in plants co-inoculated with the severe strain of CTV, B6, than when co-infected with the mild strain of CTV, B2. Plants co-infected with CaLas-B232 and either strain of CTV died but trees co-infected with CTV-B2 survived much longer than those co-infected with CTV-B6. Many important pathways were perturbed by both CTV-B2/CaLas-B232 and/or CTV-B6/CaLas-B232, but always more severely by CTV-B6/CaLas-B232. Genes related to cell wall modification and metal transport responded differently to infection by the pathogens in combination than by the same pathogens singly. The expressions of genes encoding phloem proteins and sucrose loading proteins were also differentially altered in response to CTV-B2 or CTV-B6 in combination with CaLas-B232, leading to different phloem environments in plants co-infected by CaLas and mild or severe CTV. Many host genes were expressed differently in response to dual infection as compared to single infections with the same pathogens. Interactions of the pathogens within the host may lead to a better or worse result

Metabolic interplay between the Asian citrus psyllid and its Profftella symbiont: An Achilles’ heel of the citrus greening insect vector

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‘Candidatus Liberibacter asiaticus’ (CLas), the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid. Interactions among D. citri and its microbial endosymbionts, including ‘Candidatus Profftella armatura’, are likely to impact tra...

A metabolic model for members of the genus Tetrasphaera involved in enhanced biological phosphorus removal

DEFF Research Database (Denmark)

Kristiansen, Rikke; Nguyen, Hien Thi Thu; Saunders, Aaron Marc

2013-01-01

Members of the genus Tetrasphaera are considered to be putative polyphosphate accumulating organisms (PAOs) in enhanced biological phosphorus removal (EBPR) from wastewater. Although abundant in Danish full-scale wastewater EBPR plants, how similar their ecophysiology is to ‘Candidatus Accumuliba......Members of the genus Tetrasphaera are considered to be putative polyphosphate accumulating organisms (PAOs) in enhanced biological phosphorus removal (EBPR) from wastewater. Although abundant in Danish full-scale wastewater EBPR plants, how similar their ecophysiology is to ‘Candidatus....... japonica and T. elongata. Based on the models, we propose that under anaerobic conditions the Tetrasphaerarelated PAOs take up glucose and ferment this to succinate and other components. They also synthesize glycogen as a storage polymer, using energy generated from the degradation of stored polyphosphate...... by ‘Candidatus Accumulibacter phosphatis’, and reveals Tetrasphaera populations to be unusual and physiologically versatile PAOs carrying out denitrification, fermentation and polyphosphate accumulation....

Rice paddy Nitrospirae encode and express genes related to sulfate respiration: proposal of the new genus Candidatus Sulfobium

KAUST Repository

Zecchin, Sarah

2017-10-02

Nitrospirae spp. distantly related to thermophilic, sulfate-reducing Thermodesulfovibrio species are regularly observed in environmental surveys of anoxic marine and freshwater habitats. However, little is known about their genetic make-up and physiology. Here, we present the draft genome of Nitrospirae bacterium Nbg-4 as a representative of this clade and analyzed its in situ protein expression under sulfate-enriched and sulfate-depleted conditions in rice paddy soil. The genome of Nbg-4 was assembled from replicated metagenomes of rice paddy soil that was used to grow rice plants in the presence and absence of gypsum (CaSO4x2H2O). Nbg-4 encoded the full pathway of dissimilatory sulfate reduction and showed expression thereof in gypsum-amended anoxic bulk soil as revealed by parallel metaproteomics. In addition, Nbg-4 encoded the full pathway of dissimilatory nitrate reduction to ammonia, which was expressed in bulk soil without gypsum amendment. The relative abundance of Nbg-4-related metagenome reads was similar under both treatments indicating that it maintained stable populations while shifting its energy metabolism. Further genome reconstruction revealed the potential to utilize butyrate, formate, H2, or acetate as electron donor, with the Wood-Ljungdahl pathway being expressed under both conditions. Comparison to publicly available Nitrospirae genome bins confirmed that the pathway for dissimilatory sulfate reduction is also present in related Nitrospirae recovered from groundwater. Subsequent phylogenomics showed that such microorganisms form a novel genus within the phylum Nitrospirae, with Nbg-4 as a representative species. Based on the widespread occurrence of this novel genus, we propose for Nbg 4 the name Candidatus Sulfobium mesophilum, gen. nov., spec. nov.

The quest for a non-vector psyllid: Natural variation in acquisition and transmission of the huanglongbing pathogen ‘Candidatus Liberibacter asiaticus’ by Asian citrus psyllid isofemale lines

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Ammar, El-Desouky; Hall, David G.; Hosseinzadeh, Saeed

2018-01-01

Genetic variability in insect vectors is valuable to study vector competence determinants and to select non-vector populations that may help reduce the spread of vector-borne pathogens. We collected and tested vector competency of 15 isofemale lines of Asian citrus psyllid, Diaphorina citri, vector of ‘Candidatus Liberibacter asiaticus’ (CLas). CLas is associated with huanglongbing (citrus greening), the most serious citrus disease worldwide. D. citri adults were collected from orange jasmine (Murraya paniculata) hedges in Florida, and individual pairs (females and males) were caged on healthy Murraya plants for egg laying. The progeny from each pair that tested CLas-negative by qPCR were maintained on Murraya plants and considered an isofemale line. Six acquisition tests on D. citri adults that were reared as nymphs on CLas-infected citrus, from various generations of each line, were conducted to assess their acquisition rates (percentage of qPCR-positive adults). Three lines with mean acquisition rates of 28 to 32%, were classified as ‘good’ acquirers and three other lines were classified as ‘poor’ acquirers, with only 5 to 8% acquisition rates. All lines were further tested for their ability to inoculate CLas by confining CLas-exposed psyllids for one week onto healthy citrus leaves (6–10 adults/leaf/week), and testing the leaves for CLas by qPCR. Mean inoculation rates were 19 to 28% for the three good acquirer lines and 0 to 3% for the three poor acquirer lines. Statistical analyses indicated positive correlations between CLas acquisition and inoculation rates, as well as between CLas titer in the psyllids and CLas acquisition or inoculation rates. Phenotypic and molecular characterization of one of the good and one of the poor acquirer lines revealed differences between them in color morphs and hemocyanin expression, but not the composition of bacterial endosymbionts. Understanding the genetic architecture of CLas transmission will enable the

“Candidatus Gortzia shahrazadis”, a novel endosymbiont of Paramecium multimicronucleatum and a revision of the biogeographical distribution of Holospora-like bacteria

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Valentina Serra

2016-11-01

Full Text Available Holospora spp. and Candidatus Gortzia infectiva, known as Holospora-like bacteria (HLB, are commonly found as nuclear endosymbionts of ciliates, especially the Paramecium genus. HLB are related by phylogenetic relationships, morphological features, and life cycles, which involve two alternating morphotypes: reproductive and infectious forms (RF, IF. In this paper we describe a novel species belonging to the Ca. Gortzia genus, detected in P. multimicronucleatum, a ciliate for which infection by an HLB has not been reported, discovered in India. This novel endosymbiont shows unusual and surprising features with respect to other HLB, such as large variations in IF morphology and the occasional ability to reproduce in the host cytoplasm. We propose the name of Candidatus Gortzia shahrazadis for this novel HLB . Moreover, we report two additional species of HLB from Indian Paramecium populations: Ca. Gortzia infectiva (from P. jenningsi, and H. obtusa (from P. caudatum; the latter is the first record of Holospora from a tropical country. Although tropical, we retrieved H. obtusa at an elevation of 706 m. corresponding to a moderate climate not unlike conditions where Holospora are normally found, suggesting the genus Holospora does exist in tropical countries, but restricted to higher elevations.

“Candidatus Gortzia shahrazadis”, a Novel Endosymbiont of Paramecium multimicronucleatum and a Revision of the Biogeographical Distribution of Holospora-Like Bacteria

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Serra, Valentina; Fokin, Sergei I.; Castelli, Michele; Basuri, Charan K.; Nitla, Venkatamahesh; Verni, Franco; Sandeep, Bhagavatula V.; Kalavati, Chaganti; Petroni, Giulio

2016-01-01

Holospora spp. and “Candidatus Gortzia infectiva”, known as Holospora-like bacteria (HLB), are commonly found as nuclear endosymbionts of ciliates, especially the Paramecium genus. HLB are related by phylogenetic relationships, morphological features, and life-cycles, which involve two alternating morphotypes: reproductive and infectious forms (RF, IF). In this paper we describe a novel species belonging to the “Ca. Gortzia” genus, detected in P. multimicronucleatum, a ciliate for which infection by an HLB has not been reported, discovered in India. This novel endosymbiont shows unusual and surprising features with respect to other HLB, such as large variations in IF morphology and the occasional ability to reproduce in the host cytoplasm. We propose the name of “Candidatus Gortzia shahrazadis” for this novel HLB. Moreover, we report two additional species of HLB from Indian Paramecium populations: “Ca. Gortzia infectiva” (from P. jenningsi), and H. obtusa (from P. caudatum); the latter is the first record of Holospora from a tropical country. Although tropical, we retrieved H. obtusa at an elevation of 706 m corresponding to a moderate climate not unlike conditions where Holospora are normally found, suggesting the genus Holospora does exist in tropical countries, but restricted to higher elevations. PMID:27867371

Candidatus Sodalis melophagi sp. nov.: phylogenetically independent comparative model to the tsetse fly symbiont Sodalis glossinidius.

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Tomáš Chrudimský

Full Text Available Bacteria of the genus Sodalis live in symbiosis with various groups of insects. The best known member of this group, a secondary symbiont of tsetse flies Sodalis glossinidius, has become one of the most important models in investigating establishment and evolution of insect-bacteria symbiosis. It represents a bacterium in the early/intermediate state of the transition towards symbiosis, which allows for exploring such interesting topics as: usage of secretory systems for entering the host cell, tempo of the genome modification, and metabolic interaction with a coexisting primary symbiont. In this study, we describe a new Sodalis species which could provide a useful comparative model to the tsetse symbiont. It lives in association with Melophagus ovinus, an insect related to tsetse flies, and resembles S. glossinidius in several important traits. Similar to S. glossinidius, it cohabits the host with another symbiotic bacterium, the bacteriome-harbored primary symbiont of the genus Arsenophonus. As a typical secondary symbiont, Candidatus Sodalis melophagi infects various host tissues, including bacteriome. We provide basic morphological and molecular characteristics of the symbiont and show that these traits also correspond to the early/intermediate state of the evolution towards symbiosis. Particularly, we demonstrate the ability of the bacterium to live in insect cell culture as well as in cell-free medium. We also provide basic characteristics of type three secretion system and using three reference sequences (16 S rDNA, groEL and spaPQR region we show that the bacterium branched within the genus Sodalis, but originated independently of the two previously described symbionts of hippoboscoids. We propose the name Candidatus Sodalis melophagi for this new bacterium.

Candidatus Sodalis melophagi sp. nov.: phylogenetically independent comparative model to the tsetse fly symbiont Sodalis glossinidius.

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Chrudimský, Tomáš; Husník, Filip; Nováková, Eva; Hypša, Václav

2012-01-01

Bacteria of the genus Sodalis live in symbiosis with various groups of insects. The best known member of this group, a secondary symbiont of tsetse flies Sodalis glossinidius, has become one of the most important models in investigating establishment and evolution of insect-bacteria symbiosis. It represents a bacterium in the early/intermediate state of the transition towards symbiosis, which allows for exploring such interesting topics as: usage of secretory systems for entering the host cell, tempo of the genome modification, and metabolic interaction with a coexisting primary symbiont. In this study, we describe a new Sodalis species which could provide a useful comparative model to the tsetse symbiont. It lives in association with Melophagus ovinus, an insect related to tsetse flies, and resembles S. glossinidius in several important traits. Similar to S. glossinidius, it cohabits the host with another symbiotic bacterium, the bacteriome-harbored primary symbiont of the genus Arsenophonus. As a typical secondary symbiont, Candidatus Sodalis melophagi infects various host tissues, including bacteriome. We provide basic morphological and molecular characteristics of the symbiont and show that these traits also correspond to the early/intermediate state of the evolution towards symbiosis. Particularly, we demonstrate the ability of the bacterium to live in insect cell culture as well as in cell-free medium. We also provide basic characteristics of type three secretion system and using three reference sequences (16 S rDNA, groEL and spaPQR region) we show that the bacterium branched within the genus Sodalis, but originated independently of the two previously described symbionts of hippoboscoids. We propose the name Candidatus Sodalis melophagi for this new bacterium.

Bacterial diversity analysis of Huanglongbing pathogen-infected citrus, using PhyloChip and 16S rRNA gene clone library sequencing

Energy Technology Data Exchange (ETDEWEB)

Shankar Sagaram, U.; DeAngelis, K.M.; Trivedi, P.; Andersen, G.L.; Lu, S.-E.; Wang, N.

2009-03-01

The bacterial diversity associated with citrus leaf midribs was characterized 1 from citrus groves that contained the Huanglongbing (HLB) pathogen, which has yet to be cultivated in vitro. We employed a combination of high-density phylogenetic 16S rDNA microarray and 16S rDNA clone library sequencing to determine the microbial community composition of symptomatic and asymptomatic citrus midribs. Our results revealed that citrus leaf midribs can support a diversity of microbes. PhyloChip analysis indicated that 47 orders of bacteria from 15 phyla were present in the citrus leaf midribs while 20 orders from phyla were observed with the cloning and sequencing method. PhyloChip arrays indicated that nine taxa were significantly more abundant in symptomatic midribs compared to asymptomatic midribs. Candidatus Liberibacter asiaticus (Las) was detected at a very low level in asymptomatic plants, but was over 200 times more abundant in symptomatic plants. The PhyloChip analysis was further verified by sequencing 16S rDNA clone libraries, which indicated the dominance of Las in symptomatic leaves. These data implicate Las as the pathogen responsible for HLB disease. Citrus is the most important commercial fruit crop in Florida. In recent years, citrus Huanglongbing (HLB), also called citrus greening, has severely affected Florida's citrus production and hence has drawn an enormous amount of attention. HLB is one of the most devastating diseases of citrus (6,13), characterized by blotchy mottling with green islands on leaves, as well as stunting, fruit decline, and small, lopsided fruits with poor coloration. The disease tends to be associated with a phloem-limited fastidious {alpha}-proteobacterium given a provisional Candidatus status (Candidatus Liberobacter spp. later changed to Candidatus Liberibacter spp.) in nomenclature (18,25,34). Previous studies indicate that HLB infection causes disorder in the phloem and severely impairs the translocation of assimilates in

Acquisition, Replication and Inoculation of Candidatus Liberibacter asiaticus following Various Acquisition Periods on Huanglongbing-Infected Citrus by Nymphs and Adults of the Asian Citrus Psyllid.

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El-Desouky Ammar

Full Text Available The Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae, is the primary vector of Candidatus Liberibacter asiaticus (Las implicated as causative agent of citrus huanglongbing (citrus greening, currently the most serious citrus disease worldwide. Las is transmitted by D. citri in a persistent-circulative manner, but the question of replication of this bacterium in its psyllid vector has not been resolved. Thus, we studied the effects of the acquisition access period (AAP by nymphs and adults of D. citri on Las acquisition, multiplication and inoculation/transmission. D. citri nymphs or adults (previously non-exposed to Las were caged on Las-infected citrus plants for an AAP of 1, 7 or 14 days. These 'Las-exposed' psyllids were then transferred weekly to healthy citrus or orange jasmine plants, and sampled via quantitative polymerase chain reaction (qPCR analysis 1-42 days post-first access to diseased plants (padp; all tested nymphs became adults 7-14 days padp. Our results indicate that following 1 or 7 day AAP as nymphs 49-59% of Las-exposed psyllids became Las-infected (qPCR-positive, whereas only 8-29% of the psyllids were infected following 1-14 day AAP as adults. Q-PCR analysis also indicated that Las titer in the Las-exposed psyllids (relative to that of the psyllid S20 ribosomal protein gene was: 1 significantly higher, and increasing at a faster rate, following Las acquisition as nymphs compared to that following Las acquisition as adults; 2 higher as post-acquisition time of psyllids on healthy plants increased reaching a peak at 14-28 days padp for nymphs and 21-35 days padp for adults, with Las titer decreasing or fluctuating after that; 3 higher with longer AAP on infected plants, especially with acquisition as adults. Our results strongly suggest that Las multiplies in both nymphs and adults of D. citri but attains much higher levels in a shorter period of time post-acquisition when acquired by nymphs than when acquired by

'Candidatus Phytoplasma solani', a novel taxon associated with stolbur- and bois noir-related diseases of plants.

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Quaglino, Fabio; Zhao, Yan; Casati, Paola; Bulgari, Daniela; Bianco, Piero Attilio; Wei, Wei; Davis, Robert Edward

2013-08-01

Phytoplasmas classified in group 16SrXII infect a wide range of plants and are transmitted by polyphagous planthoppers of the family Cixiidae. Based on 16S rRNA gene sequence identity and biological properties, group 16SrXII encompasses several species, including 'Candidatus Phytoplasma australiense', 'Candidatus Phytoplasma japonicum' and 'Candidatus Phytoplasma fragariae'. Other group 16SrXII phytoplasma strains are associated with stolbur disease in wild and cultivated herbaceous and woody plants and with bois noir disease in grapevines (Vitis vinifera L.). Such latter strains have been informally proposed to represent a separate species, 'Candidatus Phytoplasma solani', but a formal description of this taxon has not previously been published. In the present work, stolbur disease strain STOL11 (STOL) was distinguished from reference strains of previously described species of the 'Candidatus Phytoplasma' genus based on 16S rRNA gene sequence similarity and a unique signature sequence in the 16S rRNA gene. Other stolbur- and bois noir-associated ('Ca. Phytoplasma solani') strains shared >99 % 16S rRNA gene sequence similarity with strain STOL11 and contained the signature sequence. 'Ca. Phytoplasma solani' is the only phytoplasma known to be transmitted by Hyalesthes obsoletus. Insect vectorship and molecular characteristics are consistent with the concept that diverse 'Ca. Phytoplasma solani' strains share common properties and represent an ecologically distinct gene pool. Phylogenetic analyses of 16S rRNA, tuf, secY and rplV-rpsC gene sequences supported this view and yielded congruent trees in which 'Ca. Phytoplasma solani' strains formed, within the group 16SrXII clade, a monophyletic subclade that was most closely related to, but distinct from, that of 'Ca. Phytoplasma australiense'-related strains. Based on distinct molecular and biological properties, stolbur- and bois noir-associated strains are proposed to represent a novel species level taxon, 'Ca

Analyses of mitogenome sequences revealed that Asian citrus psyllid (Diaphorina citri) from California was related to those from Florida but different from those in Southern China

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Asian citrus psyllid (ACP, Diaphorina citri Kuwayama; Hemiptera: Liviidae) transmits “Candidatus Liberibacter asiaticus” (CLas), an unculturable alpha-proteobacterium associated with citrus Huanglongbing (HLB, yellow shoot disease, also called citrus greening disease). HLB is threatening citrus prod...

Technological Advances in Huanglongbing (HLB or Citrus Greening Disease Management

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Krishna Prasad Paudyal

2015-12-01

Full Text Available Huanglongbing (HLB, previously citrus greening disease, is the most destructive of citrus species causing major threat to the world citrus industry. The disease was reported from China in 1919 and now known to occur in more than 40 different countries of Asia, Africa, South and North America. Three species of gram negative bacterium namely Candidatus Liberibacter asiaticus, Candidatus Liberibacter africanus and Candidatus Liberibacter americanus are the casual organisms of HLB, respectively prevailing in the continent of Asia, Africa and South America. It is one of the most extensively researched subjects in citriculture world. HLB was detected in 2004 and 2005, respectively in San Paulo of Brazil and Florida of USA: the two leading citrus production hub of the world causing huge economic loss within 5 years of first detection. Since then research on HLB detection and management was further accelerated in American continents. This paper presents the scientific advancement made on detection, spread, economic losses caused by HLB in different parts of the world and controlling management strategies. Remarkable achievements have been made on HLB detection techniques including iodine test, qPCR and more recently in spectroscopy. While efforts are being made to develop resistance varieties using conventional and biotechnological tools management strategy which includes reduction of inoculums source, vector control and replant with disease-free planting materials still remains major option for HLB control. Citrus intercropping with guava have shown promising results for vector reduction.

Annotation of the Asian citrus psyllid genome reveals a reduced innate immune system

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Citrus production worldwide is currently facing significant losses due to citrus greening disease, also known as huanglongbing. The citrus greening bacteria, Candidatus Liberibacter asiaticus (CLas), is a persistent propagative pathogen transmitted by the Asian citrus psyllid, Diaphorina citri Kuway...

Deep Characterization of the Microbiomes of Calophya spp. (Hemiptera: Calophyidae) Gall-Inducing Psyllids Reveals the Absence of Plant Pathogenic Bacteria and Three Dominant Endosymbionts.

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Overholt, Will A; Diaz, Rodrigo; Rosskopf, Erin; Green, Stefan J; Overholt, William A

2015-01-01

Bacteria associated with sap-feeding insect herbivores include not only symbionts that may increase their hosts' fitness but also harmful plant pathogens. Calophya spp. gall-inducing psyllids (Hemiptera: Calophyidae) are being investigated for their potential as biological control agents of the noxious weed, Brazilian peppertree (Schinus terebinthifolia), in Florida. Although there are no examples of plant pathogen transmission by members of the family Calophyidae, several insects in the superfamily Psylloidea are known to transmit pathogenic bacteria in the genera Candidatus Liberibacter and Candidatus Phytoplasma. To determine whether Calophya spp. harbor potentially harmful plant pathogenic bacteria, we sequenced small subunit (SSU) ribosomal RNA (rRNA) gene amplicons generated from individuals from four Calophya spp. populations: All microbial SSU gene sequences fell into the bacterial domain, with 98-99% belonging to the Proteobacteria. The Calophya microbiomes contained a relatively simple community, with 49-79 operational taxonomic units (OTUs; 97%) detected, and only 5-8 OTUs with greater than 1% abundance. Candidatus Carsonella showed the highest relative abundance, with OTUs from this candidate genus representing between 51-65% of all recovered sequences. The next most abundant clade observed was an unclassified Enterobacteriacae group closely related to bacteria from the genera Buchnera and Blochmannia that ranged from 20-31% in relative abundance. Wolbachia populations were the third most abundant group and represented 7-27% of the diversity in microbial OTUs. No SSU rRNA gene sequences from putative pathogenic bacteria from the genera Ca. Liberibacter or Ca. Phytoplasma were detected in the microbiomes of the four Calophya populations. The probability that infected psyllids were present in our colonies, but were not sampled, was extremley low (1.39 x 10(-10)). As far as we are aware, our study is the first to characterize the microbiome of a candidate

Deep Characterization of the Microbiomes of Calophya spp. (Hemiptera: Calophyidae Gall-Inducing Psyllids Reveals the Absence of Plant Pathogenic Bacteria and Three Dominant Endosymbionts.

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Will A Overholt

Full Text Available Bacteria associated with sap-feeding insect herbivores include not only symbionts that may increase their hosts' fitness but also harmful plant pathogens. Calophya spp. gall-inducing psyllids (Hemiptera: Calophyidae are being investigated for their potential as biological control agents of the noxious weed, Brazilian peppertree (Schinus terebinthifolia, in Florida. Although there are no examples of plant pathogen transmission by members of the family Calophyidae, several insects in the superfamily Psylloidea are known to transmit pathogenic bacteria in the genera Candidatus Liberibacter and Candidatus Phytoplasma. To determine whether Calophya spp. harbor potentially harmful plant pathogenic bacteria, we sequenced small subunit (SSU ribosomal RNA (rRNA gene amplicons generated from individuals from four Calophya spp. populations: All microbial SSU gene sequences fell into the bacterial domain, with 98-99% belonging to the Proteobacteria. The Calophya microbiomes contained a relatively simple community, with 49-79 operational taxonomic units (OTUs; 97% detected, and only 5-8 OTUs with greater than 1% abundance. Candidatus Carsonella showed the highest relative abundance, with OTUs from this candidate genus representing between 51-65% of all recovered sequences. The next most abundant clade observed was an unclassified Enterobacteriacae group closely related to bacteria from the genera Buchnera and Blochmannia that ranged from 20-31% in relative abundance. Wolbachia populations were the third most abundant group and represented 7-27% of the diversity in microbial OTUs. No SSU rRNA gene sequences from putative pathogenic bacteria from the genera Ca. Liberibacter or Ca. Phytoplasma were detected in the microbiomes of the four Calophya populations. The probability that infected psyllids were present in our colonies, but were not sampled, was extremley low (1.39 x 10(-10. As far as we are aware, our study is the first to characterize the microbiome of

Deciphering the bacterial microbiome in huanglongbing-affected citrus treated with thermotherapy and sulfonamide antibiotics

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Huanglongbing (HLB) is a serious citrus disease that threatens the citrus industry. In previous studies, sulfonamide antibiotics and heat treatment suppressed ‘Candidatus Liberibacter asiaticus’ (Las), but did not completely eliminate the Las. Furthermore, there are few reports studying the bacteria...

Population diversity of Diaphorina citri (Hemiptera: Liviidae) in China based on whole mitochondrial genome sequences

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BACKGROUND: Diaphorina citri (Asian citrus psyllid, ACP) transmits “Candidatus Liberibacter asiaticus”, an unculturable alpha-proteobacterium associated with citrus Huanglongbing (HLB). ACP has been reported in 11 provinces/regions in China, yet its population diversity remains unclear. In this stud...

High incidence of preharvest colonization of huanglongbing-symptomatic Citrus sinensis fruit by Lasiodiplodia theobromae (Diplodia natalensis) and exacerbation of postharvest fruit decay by that fungus

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Huanglongbing (HLB), presumably caused by bacterium Candidatus Liberibacter asiaticus (CLas), is a devastating citrus disease associated with excessive pre-harvest fruit drop. Lasiodiplodia theobromae (Diplodia) is the causal organism of citrus stem end rot (SER). The pathogen infects citrus fruit ...

Cloning and expressing a highly functional and substrate specific farnesoic acid o-methyltransferase from the Asian citrus psyllid (Diaphorina citri Kuwayama)

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The Asian citrus psyllid, Diaphorina citri, transmits a phloem-limited bacterium, Candidatus Liberibacter asiaticus that causes citrus greening disease. Because juvenile hormone (JH) plays an important role in adult and nymphal development, we studied the final steps in juvenile hormone biosynthesis...

Improved annotation of the insect vector of citrus greening disease: Biocuration by a diverse genomics community

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The Asian citrus psyllid (Diaphorina citri Kuwayama) is the insect vector of the bacterium Candidatus Liberibacter asiaticus (CLas), the pathogen associated with citrus Huanglongbing (HLB, citrus greening). HLB threatens citrus production worldwide. Suppression or reduction of the insect vector usin...

Ultrastructure of the salivary glands, alimentary canal and bacteria-like organisms in the Asian citrus psyllid, vector of citrus huanglongbing-disease bacteria

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Several psyllids (Hemiptera: Psylloidea) are known as vectors of some economically important viral and bacterial plant pathogens. The Asian citrus psyllid (ACP, Diaphorina citri, Hemiptera, Liviidae) is the principal vector of ‘Candidatus Liberibacter asiaticus’ (Las), the putative bacterial causal ...

Exogenous application of the plant signalers methyl jasmonate & salicylic acid induces changes in volatile emissions from citrus foliage & influences the aggregation behavior of ACP (Diaphorina citri), vector of Huanglongbing

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Huanglongbing or citrus greening is a destructive disease that threatens citrus production worldwide; it is putatively caused by the phloem-limited bacterium Candidatus Liberibacter asiaticus (Las). Currently the disease is untreatable and control efforts focus on intensive insecticide use to contro...

Association of promising germplasm exhibiting tolerance to psyllids, aphids, and zebra chip disease with foliar host chemistry

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Long term, sustainable management of zebra chip disease of potato, caused by “Candidatus Liberibacter solanacearum” (Lso) and vectored by potato psyllids (Bactericera cockerelli Sulc), will require development of new cultivars resistant or tolerant to infection and/or capable of reducing spread. The...

Correlation of electronic monitoring and stylet pathways elucidate the role of sclerenchymatous ring as a barrier to phloem feeding on citrus leaves by Asian citrus psyllid

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Asian citrus psyllid (ACP, Diaphorina. citri) feeding behaviors play a significant role in the transmission of the phloem-limited Candidatus Liberibacter asiaticus (CLas) bacterium that causes the economically devastating citrus greening disease. Recent studies have shown a fibrous ring of thick-wal...

Overexpression of a modified plant thionin enhances disease resistance to citrus canker and huanglongbing (HLB, citrus greening)

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Huanglongbing (HLB or citrus greening disease) caused by Candidatus Liberibacter asiaticus (Las) is a great threat to the United States citrus industry. Citrus canker is also an economically important disease associated with a bacterial pathogen (Xanthomonas citri). In this study, we characterized e...

Sclerenchymatous ring as a barrier to phloem feeding by Asian citrus psyllid: Evidence from electrical penetration graph and visualization of stylet pathways

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Asian citrus psyllid (ACP) feeding behaviors play a significant role in the transmission of the phloem-limited Candidatus Liberibacter asiaticus (CLas) bacteria that cause citrus greening disease. Sustained phloem ingestion by ACP on CLas infected plants is very important in pathogen acquisition and...

Gut content analysis of a phloem-feeding insect, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae)

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Potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae) is a key pest of potato (Solanum tuberosum L., Solanales: Solanaceae) and a vector of "Candidatus Liberibacter solanacearum," the pathogen associated with zebra chip disease. In addition to its presence on cultivated crops, the p...

Within-orchard edge effects of the azimuth of the sun on Diaphorina citri adults in mature orchards

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Huanglongbing (HLB) has been considered the most devastating disease of citrus. The bacterium and vector associated with HLB in Florida are ‘Candidatus Liberibacter asiaticus’ and Diaphorina citri (Asian citrus psyllid), respectively. D. citri is positively phototropic, and higher populations have b...

Repellency of Selected Psidium guajava cultivars to the Asian citrus psyllid, Diaphorina citri

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Asiatic huanglongbing (HLB)(also known as citrus greening disease) is the most devastating disease of citrus worldwide. It is caused by a bacterium ‘Candidatus Liberibacter asiaticus’ and transmitted by the Asian citrus psyllid (ACP), Diaphorina citri. Considerable research has been conducted toward...

Characterization of a recombinant Cathepsin B-Like cysteine peptidase from Diaphorina citri Kuwayama (Hemiptera: Liviidae): A putative target control of citrus huanglongbing

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Huanglongbing (HLB) is one of the most destructive disease affecting citrus plants. The causal agent is associated with the phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas) spread by the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae). Among the control strategies for H...

Use of micro-CT to elucidate details of the anatomy and feeding of the Asian citrus psyllid Diaphorina citri Kuwayama, 1908 (Insecta: Hemiptera, Liviidae)

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Huanglongbing (HLB), also known as citrus greening disease, is caused by plant-infecting bacteria. The most prominent pathogen within the Americas: United States of America, Mexico, and Brazil, is Candidatus Liberibacter asiaticus, which affects plants of the Family: Rutaceae, in particularly citrus...

First detection of Candidatus Rickettsia barbariae in the flea Vermipsylla alakurt from north-western China.

Science.gov (United States)

Zhao, Shan-Shan; Li, Hong-Yu; Yin, Xiao-Ping; Liu, Zhi-Qiang; Chen, Chuang-Fu; Wang, Yuan-Zhi

2016-06-07

Vermipsylla is a genus of the family Vermipsyllidae within the order Siphonaptera of fleas. Vermipsylla alakurt is mainly distributed in alpine pastoral areas of Kazakhstan, Mongolia, China and Nepal, and infests sheep, yaks and horses, causing irritation, poor condition, anaemia and even death. However, to date, no rickettsial agents have been reported in V. alakurt. A total of 133 fleas were collected directly from the tails of three sheep flocks (n = 335) in Minfeng County, Xinjiang Uygur Autonomous Region, north-western China. Of these, 55 fleas were identified by morphological examination and molecular analysis of four loci (the ribosomal 18S and 28S rDNA genes and the mitochondrial genes cytochrome  c oxidase subunit II and elongation factor 1-alpha). Eight Rickettsia-specific gene fragments originated from seven genes: the 17-kilodalton antigen gene (17-kDa), citrate synthase gene (gltA), 16S rRNA gene (rrs), outer membrane protein A gene (ompA), surface cell antigen 1 gene (sca1), PS120 protein gene (gene D), and outer membrane protein B gene (ompB, two fragments), were used to identify the species of Rickettsia in 53 fleas. The amplified products were sequenced and included in a phylogenetic analysis to verify the taxonomic identification of the rickettsial agents. Based on morphological and molecular evidence, the flea was identified as Vermipsylla alakurt. Nine samples were positive (16.98 %, 9/53) for Rickettsia spp. The phylogenetic tree revealed that the rickettsial agents found in V. alakurt cluster with Candidatus Rickettsia barbariae. Our study suggests that: (i) V. alakurt may serve as a carrier for Candidatus R. barbariae; and (ii) Candidatus R. barbariae, previously reported in Israel, is the eighth newly discovered validated Rickettsia species in China. This finding extends our knowledge of the distribution of Candidatus R. barbariae and the profile of carriers, which not only comprise ticks but also fleas.

Examining the role of tuber biochemistry in the development of zebra chip in stored potato tubers

Science.gov (United States)

Zebra chip disease (ZC), associated with infection by the bacterium ‘Candidatus Liberibacter solanacearum’ (Lso), is an emerging problem for potato growers in the United States, Mexico, and New Zealand. Although potato tubers exhibiting ZC symptoms will be rejected by processors, it remains possible...

Use of the entomopathogenic fungi Metarhizium anisopliae, Cordyceps bassiana and Isaria fumosorosea to control Diaphorina citri (Hemiptera: Psylidae) in Persian lime under field conditions

Science.gov (United States)

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a destructive insect pest in the citriculture, because it is an efficient vector of the proteobacteria, ‘Candidatus Liberibacter asiaticus’ (Las), ‘Ca. L. Africanus’ (Laf), and ‘Ca. L. Americanus’ (Lam). These bacteria c...

Zebra chip development during storage: cause for concern?

Science.gov (United States)

Zebra chip disease is associated with infections by ‘Candidatus Liberibacter solanacearum’ (Lso), a bacterium spread by the potato psyllid Bactericera cockerelli. A major concern of the potato industry is the likelihood that Lso could cause asymptomatic infections prior to placement of tubers in col...

Asian citrus psyllid RNAi pathway - RNAi evidence

Science.gov (United States)

In silico analyses of the draft genome of Diaphorina citri, the Asian citrus psyllid, for genes within the Ribonucleic acid interference(RNAi), pathway was successful. The psyllid is the vector of the plant-infecting bacterium, Candidatus Liberibacter asiaticus (CLas), which is linked to citrus gree...

Biocuration and improvement of the Diaphorina citri draft genome assembly with long reads, optical maps and long-range scaffolding

Science.gov (United States)

The Asian citrus psyllid (Diaphorina citri Kuwayama) is the insect vector of the bacterium Candidatus Liberibacter asiaticus (CLas), the causal agent for the citrus greening or Huanglongbing disease which threatens citrus industry worldwide. This vector is the primary target of approaches to stop th...

H NMR analyses of Citrus macrophylla subjected to Asian citrus psyllid (Diaphorina citri Kuwayama) feeding

Science.gov (United States)

The Asian citrus psyllid (ACP) is a phloem feeding insect that can host and transmit the bacterium Candidatus Liberibacter asiaticus (CLas), which is the putative causative agent of the economically important citrus disease, Huanglongbing (HLB). ACP are widespread in Florida, and are spreading in Ca...

'Candidatus Megaira polyxenophila' gen. nov., sp. nov.: considerations on evolutionary history, host range and shift of early divergent rickettsiae.

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Martina Schrallhammer

Full Text Available "Neglected Rickettsiaceae" (i.e. those harboured by non-hematophagous eukaryotic hosts display greater phylogenetic variability and more widespread dispersal than pathogenic ones; yet, the knowledge about their actual host range and host shift mechanism is scarce. The present work reports the characterization following the full-cycle rRNA approach (SSU rRNA sequence, specific in situ hybridization, and ultrastructure of a novel rickettsial bacterium, herewith proposed as 'Candidatus Megaira polyxenophila' gen. nov., sp. nov. We found it in association with four different free-living ciliates (Diophrys oligothrix, Euplotes octocarinatus, Paramecium caudatum, and Spirostomum sp., all belonging to Alveolata, Ciliophora; furthermore it was recently observed as intracellular occurring in Carteria cerasiformis and Pleodorina japonica (Chlorophyceae, Chlorophyta. Phylogenetic analyses demonstrated the belonging of the candidate new genus to the family Rickettsiaceae (Alphaproteobacteria, Rickettsiales as a sister group of the genus Rickettsia. In situ observations revealed the ability of the candidate new species to colonize either nuclear or cytoplasmic compartments, depending on the host organism. The presence of the same bacterial species within different, evolutionary distant, hosts indicates that 'Candidatus Megaira polyxenophila' recently underwent several distinct host shifts, thus suggesting the existence of horizontal transmission pathways. We consider these findings as indicative of an unexpected spread of rickettsial infections in aquatic communities, possibly by means of trophic interactions, and hence propose a new interpretation of the origin and phylogenetic diversification of rickettsial bacteria.

'Candidatus mycoplasma haemodidelphidis' sp. nov., 'Candidatus mycoplasma haemolamae' sp. nov. and Mycoplasma haemocanis comb. nov., haemotrophic parasites from a naturally infected opossum (Didelphis virginiana), alpaca (Lama pacos) and dog (Canis familiaris): phylogenetic and secondary structural relatedness of their 16S rRNA genes to other mycoplasmas.

Science.gov (United States)

Messick, Joanne B; Walker, Pamela G; Raphael, William; Berent, Linda; Shi, Xun

2002-05-01

The 16S rRNA sequence of newly characterized haemotrophic bacteria in an opossum (Didelphis virginiana) and alpaca (Lama pacos) was determined. In addition, the 16S rRNA sequence of a haemotrophic parasite in the dog (Canis familiaris) was determined. Sequence alignment and evolutionary analysis as well as secondary structural similarity and signature nucleotide sequence motifs of their 16S rRNA genes, positioned these organisms in the genus Mycoplasma. The highest scoring sequence similarities were 16S rRNA genes from haemotrophic mycoplasma species (Haemobartonella and Eperythrozoon spp.). However, the lack of several higher-order structural idiosyncrasies used to define the pneumoniae group, suggests that these organisms and related haemotrophic mycoplasmas represent a new group of mycoplasmas. It is recommended that the organisms be named 'Candidatus Mycoplasma haemodidelphidis', 'Candidatus Mycoplasma haemolamae' and Mycoplasma haemocanis comb. nov., to provide some indication of the target cell and host species of these parasites, and to reflect their phylogenetic affiliation.

Variations in Zebra Chip disease expression and tuber biochemistry in response to vector density

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This study examined effects of the number of ‘Candidatus Liberibacter solanacearum’ (Lso)-positive psyllids feeding on potatoes to Lso titers, zebra chip disease (ZC) symptom severity, and levels of amino acids, carbohydrates, and phenolics in tubers harvested weeks later. Red La Soda and Russet Nor...

Overexpression of a modified plant thionin enhances disease resistance to citrus canker and Huanglongbing (HLB)

Science.gov (United States)

Huanglongbing (HLB or citrus greening disease) caused by Candidatus Liberibacter asiaticus (Las) is a great threat to the United States citrus industry. There are no proven strategies to eliminate HLB disease and no cultivar has been identified with strong HLB resistance. Citrus canker is also an ec...

Effects of soil-applied imidacloprid on Asian citrus psyllid (Hemiptera: Psyllidae) feeding behavior

Science.gov (United States)

The Asian citrus psyllid, Diaphorina citri Kuwayama is one of the most important pests of citrus due to its status as a vector of Candidatus Liberibacter asiaticus, the bacterium associated with huanglongbing (HLB) disease. The use of insecticides for vector control is the primary method of managing...

Effect of abscission zone formation on orange (Citrus sinensis) fruit/juice quality for trees affected by Huanglongbing (HLB)

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Orange trees affected by huanglongbing (HLB) exhibit excessive fruit drop, and fruit loosely attached to the tree may have inferior flavor. Fruit were collected from healthy and HLB-infected (Candidatus liberibacter asiaticus) ‘Hamlin’ and ‘Valencia’ trees. Prior to harvest, the trees were shaken, f...

Working towards developing potato tolerance of zebra chip disease: a food science perspective

Science.gov (United States)

Potato zebra chip is a major threat to worldwide potato production and is caused by ‘Candidatus Liberibacter solanacearum’ (Lso), which is vectored by potato psyllids. Albeit control can be achieved by use of insecticides to limit psyllid populations and therefore Lso spread, the recent development ...

Whole plant destructive screening for huanglongbing susceptibility with conetainer seedlings exposed to no-choice Asian citrus psyllid inoculation

Science.gov (United States)

Huanglongbing (HLB) is associated with Candidatus Liberibacter asiaticus (Las) and is vectored by the Asian Citrus Psyllid (ACP, Diaphorina citri). HLB is devastating the Florida citrus industry, with production reduced by 60 percent in the last 12 years, and HLB is considered the greatest threat to...

Control of Huanglongbing (HLB) disease with reference to its ...

African Journals Online (AJOL)

STORAGESEVER

2009-09-01

Sep 1, 2009 ... Most citrus fruits are produced for fresh market ... America has been named Candidatus liberibacter americanus; it was detected in Brazil ... sour oranges remained non-productive, whereas Mexican ... In the study conducted in China, 10-13 sprays per year ..... In 2005, Sarawak exported an estimated 28.35.

Huanglongbing increases Diplodia Stem End Rot in Citrus sinensis

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Huanglongbing (HLB), one of the most devastating diseases of citrus is caused by the a-Proteobacteria Candidatus Liberibacter. Diplodia natalensis Pole-Evans is a fungal pathogen which has been known to cause a postharvest stem-end rot of citrus, the pathogen infects citrus fruit under the calyx, an...

Exogenous application of methyl jasmonate and salicylic acid on citrus foliage: Effecs on foliar volatiles and aggregation behavior of Asian citrus psyllid (Diaphorina citri)

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Methyl jasmonate (MeJA) and salicylic acid (SA) are well-known activators of chemical defenses in plants. The SA pathway is involved in citrus response to infection by Candidatus Liberibacter asiaticus (CLas); less is known about the role of jasmonates in citrus defense response. We examined the eff...

'Candidatus pasteuria usgae' sp. nov., an obligate endoparasite of the phytoparasitic nematode Belonolaimus longicaudatus.

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Giblin-Davis, R M; Williams, D S; Bekal, S; Dickson, D W; Brito, J A; Becker, J O; Preston, J F

2003-01-01

Taxonomically relevant characteristics of a fastidiously Gram-positive, obligately endoparasitic prokaryote (strain S-1) that uses the phytoparasitic sting nematode Belonolaimus longicaudatus as its host are reviewed. 16S rDNA sequence similarity (> or = 93%) confirms its congeneric ranking with other Pasteuria species and strains from nematodes and cladocerans and corroborates morphological, morphometric and host range evidence suggesting a novel taxon. The 16S rDNA sequence of strain S-1 has greatest similarity (96%) to the 16S rDNA sequences of both Pasteuria penetrans from root-knot nematodes (Meloidogyne species) and the recently reported strain of Pasteuria isolated from the soybean cyst nematode Heterodera glycines. Because the obligately endoparasitic nature of prokaryotes in the genus Pasteuria prevents isolation of definitive type strains, strain S-1 is proposed as 'Candidatus Pasteuria usgae' sp. nov.

Control of Huanglongbing (HLB) disease with reference to its ...

African Journals Online (AJOL)

WBDL is a phloem limited phytoplasma disease of lime. HLB disease causing citrus greening (Candidatus liberibacter spp.) is the second most severe disease on citrus industry all over the world. HLB has destroyed an estimated 60 million trees in Africa and Asia. More than 40 countries were infected by HLB in Africa, Asia ...

Rare Freshwater Ciliate Paramecium chlorelligerum Kahl, 1935 and Its Macronuclear Symbiotic Bacterium "Candidatus Holospora parva".

Science.gov (United States)

Lanzoni, Olivia; Fokin, Sergei I; Lebedeva, Natalia; Migunova, Alexandra; Petroni, Giulio; Potekhin, Alexey

2016-01-01

Ciliated protists often form symbioses with many diverse microorganisms. In particular, symbiotic associations between ciliates and green algae, as well as between ciliates and intracellular bacteria, are rather wide-spread in nature. In this study, we describe the complex symbiotic system between a very rare ciliate, Paramecium chlorelligerum, unicellular algae inhabiting its cytoplasm, and novel bacteria colonizing the host macronucleus. Paramecium chlorelligerum, previously found only twice in Germany, was retrieved from a novel location in vicinity of St. Petersburg in Russia. Species identification was based on both classical morphological methods and analysis of the small subunit rDNA. Numerous algae occupying the cytoplasm of this ciliate were identified with ultrastructural and molecular methods as representatives of the Meyerella genus, which before was not considered among symbiotic algae. In the same locality at least fifteen other species of "green" ciliates were found, thus it is indeed a biodiversity hot-spot for such protists. A novel species of bacterial symbionts living in the macronucleus of Paramecium chlorelligerum cells was morphologically and ultrastructurally investigated in detail with the description of its life cycle and infection capabilities. The new endosymbiont was molecularly characterized following the full-cycle rRNA approach. Furthermore, phylogenetic analysis confirmed that the novel bacterium is a member of Holospora genus branching basally but sharing all characteristics of the genus except inducing connecting piece formation during the infected host nucleus division. We propose the name "Candidatus Holospora parva" for this newly described species. The described complex system raises new questions on how these microorganisms evolve and interact in symbiosis.

Rare Freshwater Ciliate Paramecium chlorelligerum Kahl, 1935 and Its Macronuclear Symbiotic Bacterium "Candidatus Holospora parva".

Directory of Open Access Journals (Sweden)

Olivia Lanzoni

Full Text Available Ciliated protists often form symbioses with many diverse microorganisms. In particular, symbiotic associations between ciliates and green algae, as well as between ciliates and intracellular bacteria, are rather wide-spread in nature. In this study, we describe the complex symbiotic system between a very rare ciliate, Paramecium chlorelligerum, unicellular algae inhabiting its cytoplasm, and novel bacteria colonizing the host macronucleus. Paramecium chlorelligerum, previously found only twice in Germany, was retrieved from a novel location in vicinity of St. Petersburg in Russia. Species identification was based on both classical morphological methods and analysis of the small subunit rDNA. Numerous algae occupying the cytoplasm of this ciliate were identified with ultrastructural and molecular methods as representatives of the Meyerella genus, which before was not considered among symbiotic algae. In the same locality at least fifteen other species of "green" ciliates were found, thus it is indeed a biodiversity hot-spot for such protists. A novel species of bacterial symbionts living in the macronucleus of Paramecium chlorelligerum cells was morphologically and ultrastructurally investigated in detail with the description of its life cycle and infection capabilities. The new endosymbiont was molecularly characterized following the full-cycle rRNA approach. Furthermore, phylogenetic analysis confirmed that the novel bacterium is a member of Holospora genus branching basally but sharing all characteristics of the genus except inducing connecting piece formation during the infected host nucleus division. We propose the name "Candidatus Holospora parva" for this newly described species. The described complex system raises new questions on how these microorganisms evolve and interact in symbiosis.

Rare Freshwater Ciliate Paramecium chlorelligerum Kahl, 1935 and Its Macronuclear Symbiotic Bacterium “Candidatus Holospora parva”

Science.gov (United States)

Lebedeva, Natalia; Migunova, Alexandra; Petroni, Giulio

2016-01-01

Ciliated protists often form symbioses with many diverse microorganisms. In particular, symbiotic associations between ciliates and green algae, as well as between ciliates and intracellular bacteria, are rather wide-spread in nature. In this study, we describe the complex symbiotic system between a very rare ciliate, Paramecium chlorelligerum, unicellular algae inhabiting its cytoplasm, and novel bacteria colonizing the host macronucleus. Paramecium chlorelligerum, previously found only twice in Germany, was retrieved from a novel location in vicinity of St. Petersburg in Russia. Species identification was based on both classical morphological methods and analysis of the small subunit rDNA. Numerous algae occupying the cytoplasm of this ciliate were identified with ultrastructural and molecular methods as representatives of the Meyerella genus, which before was not considered among symbiotic algae. In the same locality at least fifteen other species of “green” ciliates were found, thus it is indeed a biodiversity hot-spot for such protists. A novel species of bacterial symbionts living in the macronucleus of Paramecium chlorelligerum cells was morphologically and ultrastructurally investigated in detail with the description of its life cycle and infection capabilities. The new endosymbiont was molecularly characterized following the full-cycle rRNA approach. Furthermore, phylogenetic analysis confirmed that the novel bacterium is a member of Holospora genus branching basally but sharing all characteristics of the genus except inducing connecting piece formation during the infected host nucleus division. We propose the name “Candidatus Holospora parva” for this newly described species. The described complex system raises new questions on how these microorganisms evolve and interact in symbiosis. PMID:27992463

Candidate gene markers for Candidatus Liberibacter asiaticus for ...

Indian Academy of Sciences (India)

Madhugiri Nageswara-Rao1 2 Mike Irey3 Stephen M Garnsey1 Siddarame Gowda1. University of Florida, IFAS, Citrus Research and Education Center, 700 Experiment Station Road, Lake Alfred, FL 33850, USA; Department of Plant Sciences, The University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson ...

Oral delivery of double-stranded RNAs induces mortality in nymphs and adults of the Asian citrus psyllid, Diaphorina citri.

Science.gov (United States)

Galdeano, Diogo Manzano; Breton, Michèle Claire; Lopes, João Roberto Spotti; Falk, Bryce W; Machado, Marcos Antonio

2017-01-01

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is one of the most important citrus pests. ACP is the vector of the phloem-limited bacteria Candidatus Liberibacter americanus and Candidatus Liberibacter asiaticus, the causal agents of the devastating citrus disease huanglongbing (HLB). The management of HLB is based on the use of healthy young plants, eradication of infected plants and chemical control of the vector. RNA interference (RNAi) has proven to be a promising tool to control pests and explore gene functions. Recently, studies have reported that target mRNA knockdown in many insects can be induced through feeding with double-stranded RNA (dsRNA). In the current study, we targeted the cathepsin D, chitin synthase and inhibitor of apoptosis genes of adult and nymph ACP by feeding artificial diets mixed with dsRNAs and Murraya paniculata leaves placed in dsRNAs solutions, respectively. Adult ACP mortality was positively correlated with the amount of dsRNA used. Both nymphs and adult ACP fed dsRNAs exhibited significantly increased mortality over time compared with that of the controls. Moreover, qRT-PCR analysis confirmed the dsRNA-mediated RNAi effects on target mRNAs. These results showed that RNAi can be a powerful tool for gene function studies in ACP and perhaps for HLB control.

Preservation and reactivation of Candidatus Jettenia asiatica and Anammoxoglobus propionicus using different preservative agents.

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Viancelli, A; Pra, M C; Scussiato, L A; Cantão, M; Ibelli, A M G; Kunz, A

2017-11-01

Anaerobic ammonium oxidation (anammox) bacteria have peculiar characteristics that make them difficult to cultivate. The conservation of these microorganisms in culture collections or laboratories requires successful preservation and reactivation techniques. Furthermore, studies have shown that successful reactivation may be preservative dependent. Considering this, the present study aimed to evaluate the preservation and reactivation of anammox consortia enriched from swine manure treatment lagoons, by using different preservative agents at different temperatures: KNO 3 (at 4 °C), glycerol (-20 °C, -80 °C), and skimmed cow milk (-20 °C, -80 °C, -200 °C). After 4 months, the biomass was thawed (except for KNO 3 ), and the reestablishment of anammox activity was evaluated by stoichiometric coefficients. Microbial community transformation during the reactivation process was also studied by 16S rDNA sequence analysis. The results showed that the anammox biomass preserved with glycerol or skimmed cow milk at -80 °C recovered activity, while the biomass preserved with other methodologies did not reestablish activity during the studied time (90 days). The bacterial community from the biomass with anammox activity was characterized and showed the presence of Candidatus Brocadia anammoxidans, Candidatus Jettenia asiatica, and Candidatus Anammoxoglobus propionicus. Preservation with skimmed cow milk at -80 °C favored the selection of Candidatus Anammoxoglobus propionicus, while preservation with glycerol at -80 °C was successful for Candidatus Jettenia asiatica. The present study was effective on anammox sludge preservation and reactivation using low-cost processes for anammox cultures preservation, which is important for biomass transport and deammonification reactor start up. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oral delivery of double-stranded RNAs induces mortality in nymphs and adults of the Asian citrus psyllid, Diaphorina citri.

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Diogo Manzano Galdeano

Full Text Available The Asian citrus psyllid (ACP, Diaphorina citri Kuwayama, is one of the most important citrus pests. ACP is the vector of the phloem-limited bacteria Candidatus Liberibacter americanus and Candidatus Liberibacter asiaticus, the causal agents of the devastating citrus disease huanglongbing (HLB. The management of HLB is based on the use of healthy young plants, eradication of infected plants and chemical control of the vector. RNA interference (RNAi has proven to be a promising tool to control pests and explore gene functions. Recently, studies have reported that target mRNA knockdown in many insects can be induced through feeding with double-stranded RNA (dsRNA. In the current study, we targeted the cathepsin D, chitin synthase and inhibitor of apoptosis genes of adult and nymph ACP by feeding artificial diets mixed with dsRNAs and Murraya paniculata leaves placed in dsRNAs solutions, respectively. Adult ACP mortality was positively correlated with the amount of dsRNA used. Both nymphs and adult ACP fed dsRNAs exhibited significantly increased mortality over time compared with that of the controls. Moreover, qRT-PCR analysis confirmed the dsRNA-mediated RNAi effects on target mRNAs. These results showed that RNAi can be a powerful tool for gene function studies in ACP and perhaps for HLB control.

The effect of nutritional spray programs applied to mitigate symptoms of Huanglongbing on fruit drop caused by HLB and citrus canker on ‘Hamlin’ orange trees

OpenAIRE

Roberts, P. D.; Rouse, R. E.; Teems, S. S.; Sytsma, R. E.; Shobert, Z.

2014-01-01

Huanglongbing (HLB) was detected in Florida in 2005 and has reached 100% incidence in certain citrus plantings in southwest Florida. The putative causal agent of HLB in Florida is the bacterium Candidatus Liberibacter asiaticus (CLa).  Citrus canker caused by the bacterium Xanthomonas citri subsp. citri is endemic in Florida.  In 2011 and 2012, fruit drop on young ‘Hamlin’ trees with symptoms of HLB and/or citrus canker was particularly severe, with more than 90% fruit drop recorded. Nutritio...

Evidence that ‘flying dragon’ trifoliate orange delays HLB symptom expression for four sweet orange cultivars, Tahiti lime and Okitsu mandarin

OpenAIRE

Stuchi, E. S.; Reiff, E. T.; Sempionato, O. R.; Parolin, L. G.; Toledo, D. A.

2014-01-01

Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus and vectored by Diaphorina citri, was first reported in 2004 in Brazil and is currently widespread in São Paulo State. Brazil is the world’s largest sweet orange producer and has 49,000 ha cultivated with ‘Tahiti’ lime acid lime. Mandarin cultivation represents 5.5% of total citrus production in the country. In 2001, three experiments were planted in the Citrus Experimental Station (EECB), Bebedouro, Northern São Paulo State, wh...

Metabolomic comparative analysis of the phloem sap of curry leaf tree (Bergera koenegii), orange jasmine (Murraya paniculata), and Valencia sweet orange (Citrus sinensis) supports their differential responses to Huanglongbing

OpenAIRE

Killiny, Nabil

2016-01-01

Orange jasmine, Murraya paniculata and curry leaf tree, Bergera koenegii are alternative hosts for Diaphorina citri, the vector of Candidatus Liberibacter asiaticus (CLas), the pathogen of huanglongbing (HLB) in citrus. D. citri feeds on the phloem sap where CLas grows. It has been shown that orange jasmine was a better host than curry leaf tree to D. citri. In addition, CLas can infect orange jasmine but not curry leaf tree. Here, we compared the phloem sap composition of these 2 plants to t...

Neoehrlichiosis: an emerging tick-borne zoonosis caused by Candidatus Neoehrlichia mikurensis.

Science.gov (United States)

Silaghi, Cornelia; Beck, Relja; Oteo, José A; Pfeffer, Martin; Sprong, Hein

2016-03-01

Candidatus Neoehrlichia mikurensis is an emerging tick-borne pathogen causing a systemic inflammatory syndrome mostly in persons with underlying hematologic or autoimmune diseases. As it is neither well-known nor well-recognized, it might be misdiagnosed as recurrence of the underlying disease or as an unrelated arteriosclerotic vascular event. The pathogen is transmitted by hard ticks of the genus Ixodes and is closely associated with rodents in which transplacental transmission occurs. Transovarial transmission in ticks has not yet been shown. Infection rates vary greatly in ticks and rodents, but the causes for its spatiotemporal variations are largely unknown. This review summarizes the current state of knowledge on the geographical distribution and clinical importance of Ca. N. mikurensis. By elucidating the life history traits of this pathogen and determining more accurately its incidence in the human population, a better assessment of its public health relevance can be made. Most urgent research needs are the in vitro-cultivation of the pathogen, the development of specific serological tests, the determination of the full genomic sequence, the routine implementation of molecular diagnosis in diseased patients with a particular panel of underlying diseases, and promoting the knowledge about neoehrlichiosis among general practitioners, hospital physicians and the risk groups such as forest workers or immune-compromised people to raise awareness about this disease that can easily be treated when correctly diagnosed.

Enrichment of anaerobic nitrate-dependent methanotrophic ?Candidatus Methanoperedens nitroreducens? archaea from an Italian paddy field soil

OpenAIRE

Vaksmaa, Annika; Guerrero-Cruz, Simon; van Alen, Theo A.; Cremers, Geert; Ettwig, Katharina F.; L?ke, Claudia; Jetten, Mike S. M.

2017-01-01

Paddy fields are a significant source of methane and contribute up to 20% of total methane emissions from wetland ecosystems. These inundated, anoxic soils featuring abundant nitrogen compounds and methane are an ideal niche for nitrate-dependent anaerobic methanotrophs. After 2?years of enrichment with a continuous supply of methane and nitrate as the sole electron donor and acceptor, a stable enrichment dominated by ?Candidatus Methanoperedens nitroreducens? archaea and ?Candidatus Methylom...

Molecular detection of "Candidatus Mycoplasma haemominutum" in a lion (Panthera leo from a brazilian zoological garden Detecção molecular do "Candidatus Mycoplasma haemominutum" em um leão (Panthera leo de um zoológico brasileiro

Directory of Open Access Journals (Sweden)

Ana M. S. Guimaraes

2007-06-01

Full Text Available Although Mycoplasma haemofelis and "Candidatus Mycoplasma haemominutum" infections have been reported in wild cats from United States, their presence among native and captive wild cats in Brazil is still unknown. A 12 year old healthy male lion (Panthera leo from the Zoological Garden of Curitiba, Brazil was anesthetized for transportation and dental evaluation. A blood sample was obtained for a complete blood cell count (CBC and PCR analysis. DNA was extracted and fragments of Mycoplasma haemofelis and "Candidatus Mycoplasma haemominutum" 16S ribosomal RNA gene were amplified in PCR assays. CBC results were within reference intervals. A weak band of 192 pb for "Candidatus Mycoplasma haemominutum" was observed, and no band was amplified from Mycoplasma haemofelis reaction. A weak PCR band associated with normal CBC results and without visible parasitemia or clinical signs may suggest a chronic subclinical infection with "Candidatus Mycoplasma haemominutum". The lack of clinical signs may also represent the low pathogenicity of this organism; however, it is noteworthy that immune suppression caused by management and/or corticoids treatment may induce parasitemia and anemia in this animal. This detection suggests further studies in captive wild cats in Brazilian Zoological Gardens.Embora a infecção por Mycoplasma haemofelis e "Candidatus Mycoplasma haemominutum" tenha sido reportada em felinos selvagens dos Estados Unidos, sua presença entre felinos selvagens de vida livre e de cativeiro no Brasil ainda é desconhecida. Um leão macho, saudável, com 12 anos de idade, residente no Zoológico de Curitiba, Brasil, foi anestesiado para transporte e avaliação dentária. Uma amostra de sangue foi coletada para a realização do hemograma completo e análise pela Reação em Cadeia da Polimerase (PCR. O DNA foi extraído e fragmentos do gene 16SrRNA do Mycoplasma haemofelis e "Candidatus Mycoplasma haemominutum" foram submetidos à metodologia da

Compuestos volátiles de brotes de limón persa y limón mexicano asociados a síntomas del HLB (Huanglongbing).

OpenAIRE

Mendoza Peña, Estrella

2014-01-01

El Huanglongbing (HLB) es una enfermedad de los cítricos que se caracteriza por causar áreas moteadas en hojas, generar frutos deformes y decolorados, semillas abortivas, causar pérdida paulatina de la producción y provocar que la muerte de los árboles infectados sea inevitable. El agente asociado a esta enfermedad es la bacteria Candidatus Liberibacter ssp., y en México es dispersada por el vector Diaphorina citri Kuwayama (Hemiptera: Liviidae). En el presente estudio, mediante el método de ...

Pathogenic potential of a Costa Rican strain of 'Candidatus Rickettsia amblyommii' in guinea pigs (Cavia porcellus) and protective immunity against Rickettsia rickettsii.

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Rivas, Juan J; Moreira-Soto, Andrés; Alvarado, Gilberth; Taylor, Lizeth; Calderón-Arguedas, Olger; Hun, Laya; Corrales-Aguilar, Eugenia; Morales, Juan Alberto; Troyo, Adriana

2015-09-01

'Candidatus Rickettsia amblyommii' is a spotted fever group rickettsia that is not considered pathogenic, although there is serologic evidence of possible infection in animals and humans. The aim of this study was to evaluate the pathogenic potential of a Costa Rican strain of 'Candidatus R. amblyommii' in guinea pigs and determine its capacity to generate protective immunity against a subsequent infection with a local strain of Rickettsia rickettsii isolated from a human case. Six guinea pigs were inoculated with 'Candidatus R. amblyommii' strain 9-CC-3-1 and two controls with cell culture medium. Health status was evaluated, and necropsies were executed at days 2, 4, and 13. Blood and tissues were processed by PCR to detect the gltA gene, and end titers of anti-'Candidatus R. amblyommii' IgG were determined by indirect immunofluorescence. To evaluate protective immunity, another 5 guinea pigs were infected with 'Candidatus R. amblyommii' (IGPs). After 4 weeks, these 5 IGPs and 3 controls (CGPs) were inoculated with pathogenic R. rickettsii. Clinical signs and titers of anti-Rickettsia IgG were determined. IgG titers reached 1:512 at day 13 post-infection with 'Candidatus R. amblyommii'. On day 2 after inoculation, two guinea pigs had enlarged testicles and 'Candidatus R. amblyommii' DNA was detected in testicles. Histopathology confirmed piogranulomatous orchitis with perivascular inflammatory infiltrate in the epididymis. In the protective immunity assay, anti-Rickettsia IgG end titers after R. rickettsii infection were lower in IGPs than in CGPs. IGPs exhibited only transient fever, while CGP showed signs of severe disease and mortality. R. rickettsii was detected in testicles and blood of CGPs. Results show that the strain 9-CC-3-1 of 'Candidatus R. amblyommii' was able to generate pathology and an antibody response in guinea pigs. Moreover, its capacity to generate protective immunity against R. rickettsii may modulate the epidemiology and severity of Rocky

“Candidatus Phytoplasma pyri” affects behavior of Cacopsylla pyricola (Hemiptera: Psyllidae)

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Pear psylla, Cacopsylla pyricola (Hemiptera: Psyllidae), is a key pest of pear and is a vector of "Candidatus Phytoplasma pyri", the pathogen associated with pear decline disease. Although commercial pear trees are grafted to Phytoplasma-resistant rootstock, a recent report indicated that many C. p...

First detection of tick-borne "Candidatus Neoehrlichia mikurensis" in Denmark 2011

DEFF Research Database (Denmark)

Fertner, Mette Ely; Mølbak, Lars; Pihl, Thomas Peter Boye

2012-01-01

This is the first reporting of the tick-borne zoonotic bacterium "Candidatus Neoehrlichia mikurensis" in Denmark. A total of 2,625 Ixodes ricinus ticks from 58 locations in Denmark were collected and analysed for "Ca. Neoehrlichia mikurensis". A nested PCR revealed the presence of the bacterium...

A GAO hiding among the PAO

DEFF Research Database (Denmark)

McIlroy, Simon Jon; Albertsen, Mads; Stokholm-Bjerregaard, Mikkel

“Candidatus Accumulibacter phosphatis” (Accumulibacter) and the model GAO being the gammaproteobacterial “Candidatus Competibacter phosphatis” (see Oehmen et al., 2007). Here, we report the discovery of a GAO from the genus Propionivibrio, which is closely related to Accumulibacter. Propionivibrio is often...

Prevalence of ‘Candidatus Accumulibacter phosphatis’ type II under phosphate limiting conditions

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Welles, L.; Lopez Vazquez, C.M.; Hooijmans, C. M.; van Loosdrecht, Mark C.M.; Brdjanovic, D

2016-01-01

P-limitation in enhanced biological phosphorus removal (EBPR) systems fed with acetate, has generally been considered as a condition leading to enrichment of organisms of the genotype’ Candidatus Competibacter phosphatis’ expressing the glycogen-accumulating organisms (GAO) phenotype. Recent

Host and symbiont intraspecific variability: The case of Paramecium calkinsi and "Candidatus Trichorickettsia mobilis".

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Sabaneyeva, E; Castelli, M; Szokoli, F; Benken, K; Lebedeva, N; Salvetti, A; Schweikert, M; Fokin, S; Petroni, G

2018-02-01

Newly isolated strains of the ciliate Paramecium calkinsi and their cytoplasmic bacterial endosymbionts were characterized by a multidisciplinary approach, including live observation, ultrastructural investigation, and molecular analysis. Despite morphological resemblance, the characterized P. calkinsi strains showed a significant molecular divergence compared to conspecifics, possibly hinting for a cryptic speciation. The endosymbionts were clearly found to be affiliated to the species "Candidatus Trichorickettsia mobilis" (Rickettsiales, Rickettsiaceae), currently encompassing only bacteria retrieved in an obligate intracellular association with other ciliates. However, a relatively high degree of intraspecific divergence was observed as well, thus it was possible to split "Candidatus Trichorickettsia" into three subspecies, one of which represented so far only by the newly characterized endosymbionts of P. calkinsi. Other features distinguished the members of each different subspecies. In particular, the endosymbionts of P. calkinsi resided in the cytoplasm and possessed numerous peritrichous flagella, although no motility was evidenced, whereas their conspecifics in other hosts were either cytoplasmic and devoid of flagella, or macronuclear, displaying flagellar-driven motility. Moreover, contrarily to previously analyzed "Candidatus Trichorickettsia" hosts, infected P. calkinsi cells frequently became amicronucleate and demonstrated abnormal cell division, eventually leading to decline of the laboratory culture. Copyright © 2017 Elsevier GmbH. All rights reserved.

["Candidatus contubernalis alkalaceticum," an obligately syntrophic alkaliphilic bacterium capable of anaerobic acetate oxidation in a coculture with Desulfonatronum cooperativum].

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Zhilina, T N; Zavarzina, D G; Kolganova, T V; Turova, T P; Zavarzin, G A

2005-01-01

From the silty sediments of the Khadyn soda lake (Tuva), a binary sulfidogenic bacterial association capable of syntrophic acetate oxidation at pH 10.0 was isolated. An obligately syntrophic, gram-positive, spore-forming alkaliphilic rod-shaped bacterium performs acetate oxidation in a syntrophic association with a hydrogenotrophic, alkaliphilic sulfate-reducing bacterium; the latter organism was previously isolated and characterized as the new species Desulfonatronum cooperativum. Other sulfate-reducing bacteria of the genera Desulfonatronum and Desulfonatronovibrio can also act as the hydrogenotrophic partner. Apart from acetate, the syntrophic culture can oxidize ethanol, propanol, isopropanol, serine, fructose, and isobutyric acid. Selective amplification of 16S rRNA gene fragments of the acetate-utilizing syntrophic component of the binary culture was performed; it was found to cluster with clones of uncultured gram-positive bacteria within the family Syntrophomonadaceae. The acetate-oxidizing bacterium is thus the first representative of this cluster obtained in a laboratory culture. Based on its phylogenetic position, the new acetate-oxidizing syntrophic bacterium is proposed to be assigned, in a Candidate status, to a new genus and species: "Candidatus Contubernalis alkalaceticum."

First report of "Candidatus Liberibacter solanacearum" infecting eggplant in Honduras

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In May of 2012, eggplant (Solanum melongena) plants in an experimental research plot located at Zamorano in the Department of Francisco Morazán, Honduras, were observed with symptoms that included leaf chlorosis and cupping, overall stunting, and production of small and malformed fruits. The researc...

Effect of chemical compounds on the ‘Cadidatus Liberibacter asiaticus’ infected pomelo (Citrus maxima)

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Huanglongbing (HLB), also known as citrus greening, is one of the most destructive diseases affecting Rutaceae plants in many parts of the world. HLB is associated with three species of ‘Candidatus Liberibacter’ with ‘Ca. L. asiaticus’ (Las), being the most widely distributed in Thailand and Asia. T...

Effect of salt on the metabolism of 'Candidatus Accumulibacter' clade I and II

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Wang, Zhongwei; Dunne, Aislinn; van Loosdrecht, Mark C.M.; Saikaly, Pascal E.

2018-01-01

Saline wastewater is known to affect the performance of phosphate-accumulating organisms (PAOs) in enhanced biological phosphorus removal (EBPR) process. However, studies comparing the effect of salinity on different PAO clades are lacking. In this study, 'Candidatus Accumulibacter phosphatis'

An HPLC-MS Characterization of the Changes in Sweet Orange Leaf Metabolite Profile following Infection by the Bacterial Pathogen Canditatus Liberibacter asiaticus

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Huanglonbing1 (HLB) presumably caused by Canditatus Liberibacter asiaticus (Clas) threatens the commercial U.S. citrus crop of an annual value of $3 billion. The earliest significant differences between the metabolomes of leaves from greenhouse-grown sweet orange trees infected with Clas and of heal...

Shotgun metagenomic data reveals signifcant abundance but low diversity of Candidatus Scalindua marine anammox bacteria in the Arabian Sea oxygen minimum zone

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laura eVillanueva

2014-02-01

Full Text Available Anaerobic ammonium oxidizing (anammox bacteria are responsible for a significant portion of the loss of fixed nitrogen from the oceans, making them important players in the global nitrogen cycle. To date, marine anammox bacteria found in both water columns and sediments worldwide belong almost exclusively to Candidatus Scalindua species. Recently the genome assembly of a marine anammox enrichment culture dominated by Candidatus Scalindua profunda became available and can now be used as a template to study metagenome data obtained from various oxygen minimum zones. Here, we sequenced genomic DNA from suspended particulate matter recovered at the upper (170 m deep and center (600 m area of the oxygen minimum zone in the Arabian Sea by SOLiD and Ion Torrent technology. The genome of Candidatus Scalindua profunda served as a template to collect reads. Based on the mapped reads marine anammox Abundance was estimated to be at least 0.4% in the upper and 1.7% in the center area. Single nucleotide variation (SNV analysis was performed to assess diversity of the Candidatus Scalindua populations. Most highly covered were the two diagnostic anammox genes hydrazine synthase (scal_01318c, hzsA and hydrazine dehydrogenase (scal_03295, hdh, while other genes involved in anammox metabolism (narGH, nirS, amtB, focA and ACS had a lower coverage but could still be assembled and analyzed. The results show that Candidatus Scalindua is abundantly present in the Arabian Sea OMZ, but that the diversity within the ecosystem is relatively low.

Feline leprosy due to Candidatus 'Mycobacterium lepraefelis': Further clinical and molecular characterisation of eight previously reported cases and an additional 30 cases.

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O'Brien, Carolyn R; Malik, Richard; Globan, Maria; Reppas, George; McCowan, Christina; Fyfe, Janet A

2017-09-01

This paper, the last in a series of three on 'feline leprosy', provides a detailed description of disease referable to the previously unnamed species, Candidatus 'Mycobacterium lepraefelis', a close relative of the human pathogens Mycobacterium leprae and Mycobacterium lepromatosis. Cases were sourced retrospectively and prospectively for this observational study, describing clinical, geographical and molecular microbiological data for cats definitively diagnosed with Candidatus 'M lepraefelis' infection. A total of 145 cases of feline leprosy were scrutinised; 114 'new' cases were sourced from the Victorian Infectious Diseases Reference Laboratory (VIDRL) records, veterinary pathology laboratories or veterinarians, and 31 cases were derived from six published studies. Thirty-eight cats were definitively diagnosed with Candidatus 'M lepraefelis' infection. Typically, cats tended to be middle-aged or older when first infected, with a male predilection. Affected cats typically had widespread cutaneous lesions, in some cases after initially localised disease. Advanced cases were often systemically unwell. All cats had outdoor access. The histological picture was lepromatous in the majority of patients, although two cases had tuberculoid disease. In one case that underwent necropsy, lesions were evident in the liver, spleen and lungs. Treatment was varied, although most cats received a combination of oral clarithromycin and rifampicin. Prognosis for recovery was variable, but typically poor. Candidatus 'M lepraefelis' typically causes high bacterial index (lepromatous) feline leprosy that in some cases progresses to systemic mycobacteriosis. The disease has a variable clinical course and prognosis. Many cases either died or were euthanased due to the infection. Multilocus sequence analysis reveals a heterogeneous picture and further analysis of draft genome sequencing may give clues to the taxonomy and epidemiology of this organism. Prospective treatment trials and

“Candidatus Rickettsia andeanae” en Amblyomma tigrinum, San Luis, Argentina

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Gabriel CICUTTIN

2016-11-01

Full Text Available El objetivo del estudio fue detectar especies del género Rickettsia en garrapatas de la especie Amblyomma tigrinum colectadas sobre carnívoros domésticos y en sangre de caninos domésticos de la provincia de San Luis (Argentina. Entre 2013 y 2015 se colectaron 56 garrapatas adultas de la especie A. tigrinum sobre caninos y felinos domésticos, y se obtuvieron 65 muestras sanguíneas de caninos. Tres garrapatas resultaron positivas mediante la amplificación de un fragmento del espacio intergénico 23S-5S ARNr del género Rickettsia, lográndose secuenciar uno de los productos positivos. La muestra positiva secuenciada también resultó positiva por PCRs de los fragmentos de los genes gltA y ompA. Las secuencias obtenidas resultaron tener una identidad del 100 % de identidad con “Candidatus Rickettsia andeanae”. Todas las muestras sanguíneas resultaron negativas. “Ca. R. andeanae” no ha sido asociada con enfermedad en humanos o animales, sin embargo, es necesario realizar nuevas investigaciones para lograr un mayor conocimiento del riesgo potencial de transmisión de rickettsiosis en la región. SUMMARY. “Candidatus Rickettsia andeanae” in Amblyomma tigrinum ticks from San Luis (Argentina. The aim of this study was to detect species of Rickettsia in Amblyomma tigrinum ticks collected from domestic carnivores and blood of domestic dogs of San Luis (Argentina. Between 2013 and 2015, 56 adults of A. tigrinum from dogs and cats and 65 blood from dogs were collected. Three ticks were positive by amplification of a 23S-5S rRNA fragment, and the sequence of one of the positive products was obtained. The positive sample sequenced was positive by PCRs of fragments of genes gltA and ompA. The sequences obtained were 100% identical with "Candidatus Rickettsia andeanae". All blood samples were negative. “Ca. R. andeanae” has not been associated with disease in humans or animals; however, further research is necessary to achieve greater

Genomes of Candidatus Wolbachia bourtzisii wDacA and Candidatus Wolbachia pipientis wDacB from the Cochineal Insect Dactylopius coccus (Hemiptera: Dactylopiidae

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Shamayim T. Ramírez-Puebla

2016-10-01

Full Text Available Dactylopius species, known as cochineal insects, are the source of the carminic acid dye used worldwide. The presence of two Wolbachia strains in Dactylopius coccus from Mexico was revealed by PCR amplification of wsp and sequencing of 16S rRNA genes. A metagenome analysis recovered the genome sequences of Candidatus Wolbachia bourtzisii wDacA (supergroup A and Candidatus Wolbachia pipientis wDacB (supergroup B. Genome read coverage, as well as 16S rRNA clone sequencing, revealed that wDacB was more abundant than wDacA. The strains shared similar predicted metabolic capabilities that are common to Wolbachia, including riboflavin, ubiquinone, and heme biosynthesis, but lacked other vitamin and cofactor biosynthesis as well as glycolysis, the oxidative pentose phosphate pathway, and sugar uptake systems. A complete tricarboxylic acid cycle and gluconeogenesis were predicted as well as limited amino acid biosynthesis. Uptake and catabolism of proline were evidenced in Dactylopius Wolbachia strains. Both strains possessed WO-like phage regions and type I and type IV secretion systems. Several efflux systems found suggested the existence of metal toxicity within their host. Besides already described putative virulence factors like ankyrin domain proteins, VlrC homologs, and patatin-like proteins, putative novel virulence factors related to those found in intracellular pathogens like Legionella and Mycobacterium are highlighted for the first time in Wolbachia. Candidate genes identified in other Wolbachia that are likely involved in cytoplasmic incompatibility were found in wDacB but not in wDacA.

Genetic variability of Rickettsia spp. in Ixodes persulcatus/Ixodes trianguliceps sympatric areas from Western Siberia, Russia: Identification of a new Candidatus Rickettsia species.

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Igolkina, Yana P; Rar, Vera A; Yakimenko, Valeriy V; Malkova, Marina G; Tancev, Aleksey K; Tikunov, Artem Yu; Epikhina, Tamara I; Tikunova, Nina V

2015-08-01

Rickettsia spp. are the causative agents of a number of diseases in humans. These bacteria are transmitted by arthropods, including ixodid ticks. DNA of several Rickettsia spp. was identified in Ixodes persulcatus ticks, however, the association of Ixodes trianguliceps ticks with Rickettsia spp. is unknown. In our study, blood samples of small mammals (n=108), unfed adult I. persulcatus ticks (n=136), and I. persulcatus (n=12) and I. trianguliceps (n=34) ticks feeding on voles were collected in two I. persulcatus/I. trianguliceps sympatric areas in Western Siberia. Using nested PCR, ticks and blood samples were studied for the presence of Rickettsia spp. Three distinct Rickettsia species were found in ticks, but no Rickettsia species were found in the blood of examined voles. Candidatus Rickettsia tarasevichiae DNA was detected in 89.7% of unfed I. persulcatus, 91.7% of engorged I. persulcatus and 14.7% of I. trianguliceps ticks. Rickettsia helvetica DNA was detected in 5.9% of I. trianguliceps ticks. In addition, a new Rickettsia genetic variant was found in 32.4% of I. trianguliceps ticks. Sequence analysis of the 16S rRNA, gltA, ompA, оmpB and sca4 genes was performed and, in accordance with genetic criteria, a new Rickettsia genetic variant was classified as a new Candidatus Rickettsia species. We propose to name this species Candidatus Rickettsia uralica, according to the territory where this species was initially identified. Candidatus Rickettsia uralica was found to belong to the spotted fever group. The data obtained in this study leads us to propose that Candidatus Rickettsia uralica is associated with I. trianguliceps ticks. Copyright © 2015 Elsevier B.V. All rights reserved.

A phytoplasma closely related to the pigeon pea witches'-broom phytoplasma (16Sr IX) is associated with citrus huanglongbing symptoms in the state of São Paulo, Brazil.

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Teixeira, D C; Wulff, N A; Martins, E C; Kitajima, E W; Bassanezi, R; Ayres, A J; Eveillard, S; Saillard, C; Bové, J M

2008-09-01

In February 2007, sweet orange trees with characteristic symptoms of huanglongbing (HLB) were encountered in a region of São Paulo state (SPs) hitherto free of HLB. These trees tested negative for the three liberibacter species associated with HLB. A polymerase chain reaction (PCR) product from symptomatic fruit columella DNA amplifications with universal primers fD1/rP1 was cloned and sequenced. The corresponding agent was found to have highest 16S rDNA sequence identity (99%) with the pigeon pea witches'-broom phytoplasma of group 16Sr IX. Sequences of PCR products obtained with phytoplasma 16S rDNA primer pairs fU5/rU3, fU5/P7 confirm these results. With two primers D7f2/D7r2 designed based on the 16S rDNA sequence of the cloned DNA fragment, positive amplifications were obtained from more than one hundred samples including symptomatic fruits and blotchy mottle leaves. Samples positive for phytoplasmas were negative for liberibacters, except for four samples, which were positive for both the phytoplasma and 'Candidatus Liberibacter asiaticus'. The phytoplasma was detected by electron microscopy in the sieve tubes of midribs from symptomatic leaves. These results show that a phytoplasma of group IX is associated with citrus HLB symptoms in northern, central, and southern SPs. This phytoplasma has very probably been transmitted to citrus from an external source of inoculum, but the putative insect vector is not yet known.

Revised systematics of Holospora-like bacteria and characterization of "Candidatus Gortzia infectiva", a novel macronuclear symbiont of Paramecium jenningsi.

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Boscaro, Vittorio; Fokin, Sergei I; Schrallhammer, Martina; Schweikert, Michael; Petroni, Giulio

2013-01-01

The genus Holospora (Rickettsiales) includes highly infectious nuclear symbionts of the ciliate Paramecium with unique morphology and life cycle. To date, nine species have been described, but a molecular characterization is lacking for most of them. In this study, we have characterized a novel Holospora-like bacterium (HLB) living in the macronuclei of a Paramecium jenningsi population. This bacterium was morphologically and ultrastructurally investigated in detail, and its life cycle and infection capabilities were described. We also obtained its 16S rRNA gene sequence and developed a specific probe for fluorescence in situ hybridization experiments. A new taxon, "Candidatus Gortzia infectiva", was established for this HLB according to its unique characteristics and the relatively low DNA sequence similarities shared with other bacteria. The phylogeny of the order Rickettsiales based on 16S rRNA gene sequences has been inferred, adding to the available data the sequence of the novel bacterium and those of two Holospora species (Holospora obtusa and Holospora undulata) characterized for the purpose. Our phylogenetic analysis provided molecular support for the monophyly of HLBs and showed a possible pattern of evolution for some of their features. We suggested to classify inside the family Holosporaceae only HLBs, excluding other more distantly related and phenotypically different Paramecium endosymbionts.

Small RNA profiling reveals phosphorus deficiency as a contributing factor in symptom expression for citrus huanglongbing disease.

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Zhao, Hongwei; Sun, Ruobai; Albrecht, Ute; Padmanabhan, Chellappan; Wang, Airong; Coffey, Michael D; Girke, Thomas; Wang, Zonghua; Close, Timothy J; Roose, Mikeal; Yokomi, Raymond K; Folimonova, Svetlana; Vidalakis, Georgios; Rouse, Robert; Bowman, Kim D; Jin, Hailing

2013-03-01

Huanglongbing (HLB) is a devastating citrus disease that is associated with bacteria of the genus 'Candidatus Liberibacter' (Ca. L.). Powerful diagnostic tools and management strategies are desired to control HLB. Host small RNAs (sRNA) play a vital role in regulating host responses to pathogen infection and are used as early diagnostic markers for many human diseases, including cancers. To determine whether citrus sRNAs regulate host responses to HLB, sRNAs were profiled from Citrus sinensis 10 and 14 weeks post grafting with Ca. L. asiaticus (Las)-positive or healthy tissue. Ten new microRNAs (miRNAs), 76 conserved miRNAs, and many small interfering RNAs (siRNAs) were discovered. Several miRNAs and siRNAs were highly induced by Las infection, and can be potentially developed into early diagnosis markers of HLB. miR399, which is induced by phosphorus starvation in other plant species, was induced specifically by infection of Las but not Spiroplasma citri that causes citrus stubborn-a disease with symptoms similar to HLB. We found a 35% reduction of phosphorus in Las-positive citrus trees compared to healthy trees. Applying phosphorus oxyanion solutions to HLB-positive sweet orange trees reduced HLB symptom severity and significantly improved fruit production during a 3-year field trial in south-west Florida. Our molecular, physiological, and field data suggest that phosphorus deficiency is linked to HLB disease symptomology.

Genetic diversity of Diaphorina citri and its endosymbionts across east and south-east Asia.

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Wang, Yanjing; Xu, Changbao; Tian, Mingyi; Deng, Xiaoling; Cen, Yijing; He, Yurong

2017-10-01

Diaphorina citri is the vector of 'Candidatus Liberibacter asiaticus', the most widespread pathogen associated huanglongbing, the most serious disease of citrus. To enhance our understanding of the distribution and origin of the psyllid, we investigated the genetic diversity and population structures of 24 populations in Asia and one from Florida based on the mtCOI gene. Simultaneously, genetic diversity and population structures of the primary endosymbiont (P-endosymbiont) 'Candidatus Carsonella ruddii' and secondary endosymbiont (S-endosymbiont) 'Candidatus Profftella armatura' of D. citri were determined with the housekeeping genes. AMOVA analysis indicated that populations of D. citri and its endosymbionts in east and south-east Asia were genetically distinct from populations in Pakistan and Florida. Furthermore, P-endosymbiont populations displayed a strong geographical structure across east and south-east Asia, while low genetic diversity indicated the absence of genetic structure among the populations of D. citri and its S-endosymbiont across these regions. The 'Ca. C. ruddii' is more diverse and structured than the D. citri and the 'Ca. P. armatura' across east and south-east Asia. Multiple introductions of the psyllid have occurred in China. Management application for controlling the pest is proposed based on the genetic information of D. citri and its endosymbionts. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Whole-Genome Sequence of "Candidatus Profftella armatura" from Diaphorina citri in Guangdong, China.

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Wu, F; Deng, X; Liang, G; Huang, J; Cen, Y; Chen, J

2015-11-05

The genome of "Candidatus Profftella armatura" strain YCPA from Diaphorina citri in Guangdong, China, was sequenced. The strain has a chromosome of 457,565 bp, 24.3% G+C content, 364 predicted open reading frames (ORFs), and 38 RNAs, and a plasmid, pYCPA54, of 5,458 bp with 23.9% G+C content and 5 ORFs. Copyright © 2015 Wu et al.

Deciphering the Bacterial Microbiome in Huanglongbing-Affected Citrus Treated with Thermotherapy and Sulfonamide Antibiotics.

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Chuanyu Yang

Full Text Available Huanglongbing (HLB is a serious citrus disease that threatens the citrus industry. In previous studies, sulfonamide antibiotics and heat treatment suppressed 'Candidatus Liberibacter asiaticus' (Las, but did not completely eliminate the Las. Furthermore, there are few reports studying the bacterial microbiome of HLB-affected citrus treated by heat and sulfonamide antibiotics. In this study, combinations of heat (45°C or 40°C and sulfonamide treatment (sulfathiazole sodium-STZ, or sulfadimethoxine sodium-SDX were applied to HLB-affected citrus. The bacterial microbiome of HLB-affected citrus following thermotherapy and/or chemotherapy was characterized by PhyloChipTMG3-based metagenomics. Our results showed that the combination of thermotherapy at 45°C and chemotherapy with STZ and SDX was more effective against HLB than thermotherapy alone, chemotherapy alone, or a combination of thermotherapy at 40°C and chemotherapy. The PhyloChipTMG3-based results indicated that 311 empirical Operational Taxonomic Units (eOTUs were detected in 26 phyla. Cyanobacteria (18.01% were dominant after thermo-chemotherapy. Thermotherapy at 45°C decreased eOTUs (64.43% in leaf samples, compared with thermotherapy at 40°C (73.96% or without thermotherapy (90.68% and it also reduced bacterial family biodiversity. The eOTU in phylum Proteobacteria was reduced significantly and eOTU_28, representing "Candidatus Liberibacter," was not detected following thermotherapy at 45°C. Following antibiotic treatment with SDX and STZ, there was enhanced abundance of specific eOTUs belonging to the families Streptomycetaceae, Desulfobacteraceae, Chitinophagaceae, and Xanthomonadaceae, which may be implicated in increased resistance to plant pathogens. Our study further develops an integrated strategy for combating HLB, and also provides new insight into the bacterial microbiome of HLB-affected citrus treated by heat and sulfonamide antibiotics.

Reference genes for accurate transcript normalization in citrus genotypes under different experimental conditions.

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Valéria Mafra

Full Text Available Real-time reverse transcription PCR (RT-qPCR has emerged as an accurate and widely used technique for expression profiling of selected genes. However, obtaining reliable measurements depends on the selection of appropriate reference genes for gene expression normalization. The aim of this work was to assess the expression stability of 15 candidate genes to determine which set of reference genes is best suited for transcript normalization in citrus in different tissues and organs and leaves challenged with five pathogens (Alternaria alternata, Phytophthora parasitica, Xylella fastidiosa and Candidatus Liberibacter asiaticus. We tested traditional genes used for transcript normalization in citrus and orthologs of Arabidopsis thaliana genes described as superior reference genes based on transcriptome data. geNorm and NormFinder algorithms were used to find the best reference genes to normalize all samples and conditions tested. Additionally, each biotic stress was individually analyzed by geNorm. In general, FBOX (encoding a member of the F-box family and GAPC2 (GAPDH was the most stable candidate gene set assessed under the different conditions and subsets tested, while CYP (cyclophilin, TUB (tubulin and CtP (cathepsin were the least stably expressed genes found. Validation of the best suitable reference genes for normalizing the expression level of the WRKY70 transcription factor in leaves infected with Candidatus Liberibacter asiaticus showed that arbitrary use of reference genes without previous testing could lead to misinterpretation of data. Our results revealed FBOX, SAND (a SAND family protein, GAPC2 and UPL7 (ubiquitin protein ligase 7 to be superior reference genes, and we recommend their use in studies of gene expression in citrus species and relatives. This work constitutes the first systematic analysis for the selection of superior reference genes for transcript normalization in different citrus organs and under biotic stress.

Sulfur volatiles from Allium spp. affect Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), response to citrus volatiles.

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Mann, R S; Rouseff, R L; Smoot, J M; Castle, W S; Stelinski, L L

2011-02-01

The Asian citrus psyllid, Diaphorina citri Kuwayama, vectors Candidatus Liberibacter asiaticus (Las) and Candidatus Liberibacter americanus (Lam), the presumed causal agents of huanglongbing. D. citri generally rely on olfaction and vision for detection of host cues. Plant volatiles from Allium spp. (Alliaceae) are known to repel several arthropod species. We examined the effect of garlic chive (A. tuberosum Rottl.) and wild onion (A. canadense L.) volatiles on D. citri behaviour in a two-port divided T-olfactometer. Citrus leaf volatiles attracted significantly more D. citri adults than clean air. Volatiles from crushed garlic chive leaves, garlic chive essential oil, garlic chive plants, wild onion plants and crushed wild onion leaves all repelled D. citri adults when compared with clean air, with the first two being significantly more repellent than the others. However, when tested with citrus volatiles, only crushed garlic chive leaves and garlic chive essential oil were repellent, and crushed wild onions leaves were not. Analysis of the headspace components of crushed garlic chive leaves and garlic chive essential oil by gas chromatography-mass spectrometry revealed that monosulfides, disulfides and trisulfides were the primary sulfur volatiles present. In general, trisulfides (dimethyl trisulfide) inhibited the response of D. citri to citrus volatiles more than disulfides (dimethyl disulfide, allyl methyl disulfide, allyl disulfide). Monosulfides did not affect the behaviour of D. citri adults. A blend of dimethyl trisulfide and dimethyl disulfide in 1:1 ratio showed an additive effect on inhibition of D. citri response to citrus volatiles. The plant volatiles from Allium spp. did not affect the behaviour of the D. citri ecto-parasitoid Tamarixia radiata (Waterston). Thus, Allium spp. or the tri- and di-sulphides could be integrated into management programmes for D. citri without affecting natural enemies.

Behavior of bacteriome symbionts during transovarial transmission and development of the Asian citrus psyllid.

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Hiroki Dan

Full Text Available The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae is a serious pest worldwide, transmitting Candidatus Liberibacter spp. (Alphaproteobacteria, the causative agents of a devastating citrus disease known as huanglongbing or greening disease. In a symbiotic organ called the bacteriome, D. citri possesses an organelle-like defensive symbiont, Candidatus Profftella armatura (Betaproteobacteria, and a nutritional symbiont, Ca. Carsonella ruddii (Gammaproteobacteria. Drastically reduced symbiont genomes and metabolic complementarity among the symbionts and D. citri indicate their mutually indispensable association. Moreover, horizontal gene transfer between the Profftella and Liberibacter lineages suggests ecological and evolutionary interactions between the bacteriome symbiont and the HLB pathogen. Using fluorescence in situ hybridization, we examined the behavior of Profftella and Carsonella during transovarial transmission and the development of D. citri. In the bacteriomes of sexually-mature female adults, symbionts transformed from an extremely elongated tubular form into spherical or short-rod forms, which migrated toward the ovary. The symbionts then formed mosaic masses, which entered at the posterior pole of the vitellogenic oocytes. After anatrepsis, Carsonella and Profftella migrated to the central and peripheral parts of the mass, respectively. Following the appearance of host nuclei, the mass cellularized, segregating Carsonella and Profftella in the central syncytium and peripheral uninucleate bacteriocytes, respectively. Subsequently, the uninucleate bacteriocytes harboring Profftella assembled at the posterior pole, while the syncytium, containing Carsonella, sat on the anterior side facing the germ band initiating katatrepsis. During dorsal closure, the syncytium was divided into uninuclear bacteriocytes, which surrounded the mass of bacteriocytes containing Profftella. Once fully surrounded, the bacteriocyte mass

Enrichment and physiological characterization of an anaerobic ammonium-oxidizing bacterium ‘ Candidatus Brocadia sapporoensis’

KAUST Repository

Narita, Yuko; Zhang, Lei; Kimura, Zen-ichiro; Ali, Muhammad; Fujii, Takao; Okabe, Satoshi

2017-01-01

Anaerobic ammonium-oxidation (anammox) is recognized as an important microbial process in the global nitrogen cycle and wastewater treatment. In this study, we successfully enriched a novel anammox bacterium affiliated with the genus ‘Candidatus Brocadia’ with high purity (>90%) in a membrane bioreactor (MBR). The enriched bacterium was distantly related to the hitherto characterized ‘Ca. Brocadia fulgida’ and ‘Ca. Brocadia sinica’ with 96% and 93% of 16S ribosomal RNA gene sequence identity, respectively. The bacterium exhibited the common structural features of anammox bacteria and the production of hydrazine in the presence of hydroxylamine under anoxic conditions. The temperature range of anammox activity was 20 − 45°C with a maximum activity at 37°C. The maximum specific growth rate (μmax) was determined to be 0.0082h−1 at 37°C, corresponding to a doubling time of 3.5 days. The half-saturation constant (KS) for nitrite was 5±2.5μM. The anammox activity was inhibited by nitrite with 11.6mM representing the 50% inhibitory concentration (IC50) but no significant inhibition was observed in the presence of formate and acetate. The major respiratory quinone was identified to be menaquinone-7 (MK-7). Comparative genome analysis revealed that the anammox bacterium enriched in present study shared nearly half of genes with ‘Ca. Brocadia sinica’ and ‘Ca. Brocadia fulgida’. The bacterium enriched in this study showed all known physiological characteristics of anammox bacteria and can be distinguished from the close relatives by its rRNA gene sequences. Therefore, we proposed the name ‘Ca. Brocadia sapporoensis’ sp. nov.

Enrichment and physiological characterization of an anaerobic ammonium-oxidizing bacterium ‘ Candidatus Brocadia sapporoensis’

KAUST Repository

Narita, Yuko

2017-08-18

Anaerobic ammonium-oxidation (anammox) is recognized as an important microbial process in the global nitrogen cycle and wastewater treatment. In this study, we successfully enriched a novel anammox bacterium affiliated with the genus ‘Candidatus Brocadia’ with high purity (>90%) in a membrane bioreactor (MBR). The enriched bacterium was distantly related to the hitherto characterized ‘Ca. Brocadia fulgida’ and ‘Ca. Brocadia sinica’ with 96% and 93% of 16S ribosomal RNA gene sequence identity, respectively. The bacterium exhibited the common structural features of anammox bacteria and the production of hydrazine in the presence of hydroxylamine under anoxic conditions. The temperature range of anammox activity was 20 − 45°C with a maximum activity at 37°C. The maximum specific growth rate (μmax) was determined to be 0.0082h−1 at 37°C, corresponding to a doubling time of 3.5 days. The half-saturation constant (KS) for nitrite was 5±2.5μM. The anammox activity was inhibited by nitrite with 11.6mM representing the 50% inhibitory concentration (IC50) but no significant inhibition was observed in the presence of formate and acetate. The major respiratory quinone was identified to be menaquinone-7 (MK-7). Comparative genome analysis revealed that the anammox bacterium enriched in present study shared nearly half of genes with ‘Ca. Brocadia sinica’ and ‘Ca. Brocadia fulgida’. The bacterium enriched in this study showed all known physiological characteristics of anammox bacteria and can be distinguished from the close relatives by its rRNA gene sequences. Therefore, we proposed the name ‘Ca. Brocadia sapporoensis’ sp. nov.

'Candidatus Rickettsia mendelii', a novel basal group rickettsia detected in Ixodes ricinus ticks in the Czech Republic

Czech Academy of Sciences Publication Activity Database

Hajdušková, Eva; Literák, I.; Papoušek, I.; Costa, F.B.; Nováková, M.; Labruna, M. B.; Zdražilová-Dubská, L.

2016-01-01

Roč. 7, č. 3 (2016), s. 482-486 ISSN 1877-959X Institutional support: RVO:60077344 Keywords : Rickettsiae * Candidatus Rickettsia mendelii * Ixodes ricinus * basal group rickettsiae * ticks * Czech Republic Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.230, year: 2016

High-throughput screening of tick-borne pathogens in Europe

DEFF Research Database (Denmark)

Michelet, Lorraine; Delannoy, Sabine; Devillers, Elodie

2014-01-01

was conducted on 7050 Ixodes ricinus nymphs collected from France, Denmark, and the Netherlands using a powerful new high-throughput approach. This advanced methodology permitted the simultaneous detection of 25 bacterial, and 12 parasitic species (including; Borrelia, Anaplasma, Ehrlichia, Rickettsia......, Bartonella, Candidatus Neoehrlichia, Coxiella, Francisella, Babesia, and Theileria genus) across 94 samples. We successfully determined the prevalence of expected (Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Rickettsia helvetica, Candidatus Neoehrlichia mikurensis, Babesia divergens, Babesia...

Metabolic Interplay between the Asian Citrus Psyllid and Its Profftella Symbiont: An Achilles' Heel of the Citrus Greening Insect Vector.

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John S Ramsey

Full Text Available 'Candidatus Liberibacter asiaticus' (CLas, the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid. Interactions among D. citri and its microbial endosymbionts, including 'Candidatus Profftella armatura', are likely to impact transmission of CLas. We used quantitative mass spectrometry to compare the proteomes of CLas(+ and CLas(- populations of D. citri, and found that proteins involved in polyketide biosynthesis by the endosymbiont Profftella were up-regulated in CLas(+ insects. Mass spectrometry analysis of the Profftella polyketide diaphorin in D. citri metabolite extracts revealed the presence of a novel diaphorin-related polyketide and the ratio of these two polyketides was changed in CLas(+ insects. Insect proteins differentially expressed between CLas(+ and CLas(- D. citri included defense and immunity proteins, proteins involved in energy storage and utilization, and proteins involved in endocytosis, cellular adhesion, and cytoskeletal remodeling which are associated with microbial invasion of host cells. Insight into the metabolic interdependence between the insect vector, its endosymbionts, and the citrus greening pathogen reveals novel opportunities for control of this disease, which is currently having a devastating impact on citrus production worldwide.

Candidatus Nitrosocaldus cavascurensis, an Ammonia Oxidizing, Extremely Thermophilic Archaeon with a Highly Mobile Genome

OpenAIRE

Abby, Sophie S.; Melcher, Michael; Kerou, Melina; Krupovic, Mart; Stieglmeier, Michaela; Rossel, Claudia; Pfeifer, Kevin; Schleper, Christa

2018-01-01

Ammonia oxidizing archaea (AOA) of the phylum Thaumarchaeota are widespread in moderate environments but their occurrence and activity has also been demonstrated in hot springs. Here we present the first enrichment of a thermophilic representative with a sequenced genome, which facilitates the search for adaptive strategies and for traits that shape the evolution of Thaumarchaeota. Candidatus Nitrosocaldus cavascurensis has been enriched from a hot spring in Ischia, Italy. It grows optimally ...

The Stable Concordance Genus

OpenAIRE

Kearney, M. Kate

2013-01-01

The concordance genus of a knot is the least genus of any knot in its concordance class. Although difficult to compute, it is a useful invariant that highlights the distinction between the three-genus and four-genus. In this paper we define and discuss the stable concordance genus of a knot, which describes the behavior of the concordance genus under connected sum.

Feline leprosy due to Candidatus 'Mycobacterium tarwinense':Further clinical and molecular characterisation of 15 previously reported cases and an additional 27 cases

Science.gov (United States)

O'Brien, Carolyn R; Malik, Richard; Globan, Maria; Reppas, George; McCowan, Christina; Fyfe, Janet A

2017-05-01

This paper, the first in a series of three on 'feline leprosy', provides a detailed description of disease referable to Candidatus 'Mycobacterium tarwinense', the most common cause of feline leprosy in Victoria, Australia. Cases were sourced retrospectively and prospectively for this observational study, describing clinical, geographical and molecular microbiological data for cats definitively diagnosed with Candidatus 'M tarwinense' infection. A total of 145 cases of feline leprosy were scrutinised; 114 'new' cases were sourced from the Victorian Infectious Diseases Reference Laboratory records, veterinary pathology laboratories or veterinarians, and 31 cases were derived from six published studies. Forty-two cats were definitively diagnosed with Candidatus 'M tarwinense' infection. Typically, cats were between 3 and 11 years of age, with no gender predilection, and were generally systemically well. All had outdoor access. Most cats underwent surgical resection of lesions with adjunctive medical therapy, often utilising a combination of oral clarithromycin and rifampicin for at least 3 months. Prognosis for recovery was generally good. Resolution of lesions was not observed in the absence of treatment, but a number of untreated cats continued to enjoy an acceptable quality of life despite persistence of the disease, which extended locally but did not appear to disseminate to internal organs. Preliminary results of draft genome sequencing confirmed that the species is a member of the Mycobacterium simiae complex. Candidatus 'M tarwinense', a fastidious member of the M simiae complex, is capable of causing feline leprosy with a tendency to produce lesions on the head, particularly involving the eyes and periocular skin. The disease has an indolent clinical course and generally responds favourably to therapy despite lesions often containing large numbers of organisms. Detailed genomic analysis may yield clues as to the environmental niche and culture requirement of

A new case of the enigmatic Candidatus Neoehrlichia sp (FU98) in a fox from the Czech Republic

Czech Academy of Sciences Publication Activity Database

Hodžić, A.; Mitková, B.; Modrý, David; Juránková, J.; Frgelecová, L.; Forejtek, P.; Steinbauer, V.; Duscher, G. G.

2017-01-01

Roč. 31, 1 February (2017), s. 59-60 ISSN 0890-8508 Institutional support: RVO:60077344 Keywords : Candidatus Neoehrlichia sp. * 16S rRNA * groEL * blood * red fox * Czech Republic Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine OBOR OECD: Veterinary science Impact factor: 1.403, year: 2016

Candidatus Paraporphyromonas polyenzymogenes” encodes multi-modular cellulases linked to the Type IX secretion system

Energy Technology Data Exchange (ETDEWEB)

Naas, Adrian; Solden, Lindsey; Norbeck, Angela D.; Brewer, Heather M.; Hagen, Live; Heggenes, Ingrid; Mchardy, Alice C.; Mackie, Roderick I.; Pasa Tolic, Ljiljana; Arntzen, Magnus Ø.; Eijsink, Vincent G.; Koropatkin, Nicole; Hess, Matthias; Wrighton, Kelly C.; Pope, Phillip

2018-03-01

In Nature, obligate herbivorous ruminants have a close symbiotic relationship with their gastrointestinal microbiome, which proficiently deconstructs plant biomass. Despite decades of research, lignocellulose degradation in the rumen has thus far been attributed to a limited number of culturable microorganisms. Here, we combine meta-omics and enzymology to identify and describe a novel Bacteroidetes family (“Candidatus MH11”) composed entirely of uncultivated strains that are predominant in ruminants and only distantly related to previously characterized taxa.

'Candidatus Rickettsia mendelii', a novel basal group rickettsia detected in Ixodes ricinus ticks in the Czech Republic.

Science.gov (United States)

Hajduskova, Eva; Literak, Ivan; Papousek, Ivo; Costa, Francisco B; Novakova, Marketa; Labruna, Marcelo B; Zdrazilova-Dubska, Lenka

2016-04-01

A novel rickettsial sequence in the citrate synthase gltA gene indicating a novel Rickettsia species has been detected in 7 out of 4524 Ixodes ricinus ticks examined within several surveys performed in the Czech Republic from 2005 to 2009. This new Candidatus Rickettsia sp. sequence has been found in 2 nymphs feeding on wild birds (Luscinia megarhynchos and Erithacus rubecula), in a male tick from vegetation, and 4 ticks feeding on a dog (3 males, 1 female tick). Portions of the ompA, ompB, sca4, and htrA genes were not amplifiable in these samples. A maximum likelihood tree of rickettsiae based on comparisons of partial amino acid sequences of citrate synthase and nucleotide sequences of 16S rDNA genes and phylogenetic analysis revealed a basal position of the novel species in the proximity of R. bellii and R. canadensis. The novel species has been named 'Candidatus Rickettsia mendelii' after the founder of genetics, Gregor Mendel. Copyright © 2016 Elsevier GmbH. All rights reserved.

The genus Bipolaris

NARCIS (Netherlands)

Manamgoda, D.S.; Rossman, A.Y.; Castlebury, L.A.; Crous, P.W.; Madrid, H.; Chukeatirote, E.; Hyde, K.D.

2014-01-01

The genus Bipolaris includes important plant pathogens with worldwide distribution. Species recognition in the genus has been uncertain due to the lack of molecular data from ex-type cultures as well as overlapping morphological characteristics. In this study, we revise the genus Bipolaris based on

The genus Bipolaris.

Science.gov (United States)

Manamgoda, D S; Rossman, A Y; Castlebury, L A; Crous, P W; Madrid, H; Chukeatirote, E; Hyde, K D

2014-09-01

The genus Bipolaris includes important plant pathogens with worldwide distribution. Species recognition in the genus has been uncertain due to the lack of molecular data from ex-type cultures as well as overlapping morphological characteristics. In this study, we revise the genus Bipolaris based on DNA sequence data derived from living cultures of fresh isolates, available ex-type cultures from worldwide collections and observation of type and additional specimens. Combined analyses of ITS, GPDH and TEF gene sequences were used to reconstruct the molecular phylogeny of the genus Bipolaris for species with living cultures. The GPDH gene is determined to be the best single marker for species of Bipolaris. Generic boundaries between Bipolaris and Curvularia are revised and presented in an updated combined ITS and GPDH phylogenetic tree. We accept 47 species in the genus Bipolaris and clarify the taxonomy, host associations, geographic distributions and species' synonymies. Modern descriptions and illustrations are provided for 38 species in the genus with notes provided for the other taxa when recent descriptions are available. Bipolaris cynodontis, B. oryzae, B. victoriae, B. yamadae and B. zeicola are epi- or neotypified and a lectotype is designated for B. stenospila. Excluded and doubtful species are listed with notes on taxonomy and phylogeny. Seven new combinations are introduced in the genus Curvularia to accomodate the species of Bipolaris transferred based on the phylogenetic analysis. A taxonomic key is provided for the morphological identification of species within the genus.

Inter-Population Variability of Endosymbiont Densities in the Asian Citrus Psyllid (Diaphorina citri Kuwayama).

Science.gov (United States)

Chu, Chia-Ching; Gill, Torrence A; Hoffmann, Mark; Pelz-Stelinski, Kirsten S

2016-05-01

The Asian citrus psyllid (Diaphorina citri Kuwayama) is an insect pest capable of transmitting Candidatus Liberibacter asiaticus (CLas), the causal agent of citrus greening in North America. D. citri also harbors three endosymbionts, Wolbachia, Candidatus Carsonella ruddii, and Candidatus Profftella armatura, which may influence D. citri physiology and fitness. Although genomic researches on these bacteria have been conducted, much remains unclear regarding their ecology and inter-population variability in D. citri. The present work examined the densities of each endosymbiont in adult D. citri sampled from different populations using quantitative PCR. Under field conditions, the densities of all three endosymbionts positively correlated with each other, and they are associated with D. citri gender and locality. In addition, the infection density of CLas also varied across populations. Although an analysis pooling D. citri from different populations showed that CLas-infected individuals tended to have lower endosymbiont densities compared to uninfected individuals, the difference was not significant when the population was included as a factor in the analysis, suggesting that other population-specific factors may have stronger effects on endosymbiont densities. To determine whether there is a genetic basis to the density differences, endosymbiont densities between aged CLas-negative females of two D. citri populations reared under standardized laboratory conditions were compared. Results suggested that inter-population variability in Wolbachia infection density is associated with the genotypes of the endosymbiont or the host. Findings from this work could facilitate understanding of D. citri-bacterial associations that may benefit the development of approaches for managing citrus greening, such as prevention of CLas transmission.

Phylogenetic Variants of Rickettsia africae, and Incidental Identification of "Candidatus Rickettsia Moyalensis" in Kenya.

Science.gov (United States)

Kimita, Gathii; Mutai, Beth; Nyanjom, Steven Ger; Wamunyokoli, Fred; Waitumbi, John

2016-07-01

Rickettsia africae, the etiological agent of African tick bite fever, is widely distributed in sub-Saharan Africa. Contrary to reports of its homogeneity, a localized study in Asembo, Kenya recently reported high genetic diversity. The present study aims to elucidate the extent of this heterogeneity by examining archived Rickettsia africae DNA samples collected from different eco-regions of Kenya. To evaluate their phylogenetic relationships, archived genomic DNA obtained from 57 ticks a priori identified to contain R. africae by comparison to ompA, ompB and gltA genes was used to amplify five rickettsial genes i.e. gltA, ompA, ompB, 17kDa and sca4. The resulting amplicons were sequenced. Translated amino acid alignments were used to guide the nucleotide alignments. Single gene and concatenated alignments were used to infer phylogenetic relationships. Out of the 57 DNA samples, three were determined to be R. aeschlimanii and not R. africae. One sample turned out to be a novel rickettsiae and an interim name of "Candidatus Rickettsia moyalensis" is proposed. The bonafide R. africae formed two distinct clades. Clade I contained 9% of the samples and branched with the validated R. africae str ESF-5, while clade II (two samples) formed a distinct sub-lineage. This data supports the use of multiple genes for phylogenetic inferences. It is determined that, despite its recent emergence, the R. africae lineage is diverse. This data also provides evidence of a novel Rickettsia species, Candidatus Rickettsia moyalensis.

Oral delivery of double-stranded RNAs and siRNAs induces RNAi effects in the potato/tomato psyllid, Bactericerca cockerelli.

Directory of Open Access Journals (Sweden)

Hada Wuriyanghan

Full Text Available The potato/tomato psyllid, Bactericerca cockerelli (B. cockerelli, and the Asian citrus psyllid, Diaphorina citri (D. citri, are very important plant pests, but they are also vectors of phloem-limited bacteria that are associated with two devastating plant diseases. B. cockerelli is the vector of Candidatus Liberibacter psyllaurous (solanacearum, which is associated with zebra chip disease of potatoes, and D. citri is the vector of Ca. Liberibacter asiaticus, which is associated with the Huanglongbing (citrus greening disease that currently threatens the entire Florida citrus industry. Here we used EST sequence information from D. citri to identify potential targets for RNA interference in B. cockerelli. We targeted ubiquitously expressed and gut-abundant mRNAs via injection and oral acquisition of double-stranded RNAs and siRNAs and were able to induce mortality in recipient psyllids. We also showed knockdown of target mRNAs, and that oral acquisition resulted primarily in mRNA knockdown in the psyllid gut. Concurrent with gene knockdown was the accumulation of target specific ∼ 21 nucleotide siRNAs for an abundant mRNA for BC-Actin. These results showed that RNAi can be a powerful tool for gene function studies in psyllids, and give support for continued efforts for investigating RNAi approaches as possible tools for psyllid and plant disease control.

Occurrence and phylogenetic analysis of ‘Candidatus Mycoplasma haemominutum’ in wild felines from Paraná, Brazil

Directory of Open Access Journals (Sweden)

Claudia Mello Ribeiro

2017-08-01

Full Text Available Hemoplasma infections are emerging and wild fauna can represent an important reservoir of these pathogens. However, there are very few epidemiological studies about the occurrence of hemoplasmas in wild cats around the world. The purpose of this study is twofold: (1 evaluate the occurrence and phylogeny of hemoplasmas in captive wild felines at a zoo in the state of Paraná, Brazil, and (2 verify the correlation between subpopulations of these bacteria and the hematological and biochemical parameters of the animals. PCR was used to detect hemoplasmas in the blood of three cougars (Puma concolor, a jaguar (Panthera onca, a tiger (Panthera tigris and a lion (Panthera leo, followed by sequencing and phylogenetic analysis. The cougars and jaguar were found to be hemoplasma-positive by PCR. The phylogenetic analysis of the 16S rRNA gene sequences enabled the identification of genotypes of ‘Candidatus Mycoplasma haemominutum’ circulating in this zoo. The identified sequences were closely related to hemoplasma sequences originating from domestic cats and other wild cats, but the infected cougars and jaguar were healthy and showed no hematological or biochemical changes. It was concluded that P. concolor and P. onca are exposed to ‘Candidatus Mycoplasma haemominutum’ in Paraná, but further research is suggested to assess the resistance of wild cats to different hemoplasma subpopulations.

Genus Ranges of Chord Diagrams.

Science.gov (United States)

Burns, Jonathan; Jonoska, Nataša; Saito, Masahico

2015-04-01

A chord diagram consists of a circle, called the backbone, with line segments, called chords, whose endpoints are attached to distinct points on the circle. The genus of a chord diagram is the genus of the orientable surface obtained by thickening the backbone to an annulus and attaching bands to the inner boundary circle at the ends of each chord. Variations of this construction are considered here, where bands are possibly attached to the outer boundary circle of the annulus. The genus range of a chord diagram is the genus values over all such variations of surfaces thus obtained from a given chord diagram. Genus ranges of chord diagrams for a fixed number of chords are studied. Integer intervals that can be, and those that cannot be, realized as genus ranges are investigated. Computer calculations are presented, and play a key role in discovering and proving the properties of genus ranges.

Detection of Rickettsia helvetica and Candidatus R. tarasevichiae DNA in Ixodes persulcatus ticks collected in Northeastern European Russia (Komi Republic).

Science.gov (United States)

Kartashov, Mikhail Yu; Glushkova, Ludmila I; Mikryukova, Tamara P; Korabelnikov, Igor V; Egorova, Yulia I; Tupota, Natalia L; Protopopova, Elena V; Konovalova, Svetlana N; Ternovoi, Vladimir A; Loktev, Valery B

2017-06-01

The number of tick-borne infections in the northern European regions of Russia has increased considerably in the last years. In the present study, 676 unfed adult Ixodes persulcatus ticks were collected in the Komi Republic from 2011 to 2013 to study tick-borne rickettsioses. Rickettsia spp. DNA was detected by PCR in 51 (7.6%) ticks. The nucleotide sequence analysis of gltA fragments (765bp) from 51 ticks indicated that 60.8% and 39.2% of the ticks were infected with Rickettsia helvetica and Candidatus R. tarasevichiae, respectively. The gltA fragments showed 100% identity with those of Candidatus R. tarasevichiae previously discovered in Siberia and China, whereas R. helvetica showed 99.9% sequence identity with European isolates. The ompB had 8 nucleotide substitutions, 6 of which resulted in amino acid substitutions. In the sca9 gene, 3 nucleotide substitutions were detected, and only one resulted in amino acid substitution. The smpA, ompW, and β-lactamase genes of R. helvetica also showed a high level of sequence identity. Copyright © 2017 Elsevier GmbH. All rights reserved.

Single-Cell (Meta-Genomics of a Dimorphic Candidatus Thiomargarita nelsonii Reveals Genomic Plasticity

Directory of Open Access Journals (Sweden)

Beverly E. Flood

2016-05-01

Full Text Available The genus Thiomargarita includes the world’s largest bacteria. But as uncultured organisms, their physiology, metabolism, and basis for their gigantism are not well understood. Thus a genomics approach, applied to a single Candidatus Thiomargarita nelsonii cell was employed to explore the genetic potential of one of these enigmatic giant bacteria. The Thiomargarita cell was obtained from an assemblage of budding Ca. T. nelsonii attached to a provannid gastropod shell from Hydrate Ridge, a methane seep offshore of Oregon, USA. Here we present a manually curated genome of Bud S10 resulting from a hybrid assembly of long Pacific Biosciences and short Illumina sequencing reads. With respect to inorganic carbon fixation and sulfur oxidation pathways, the Ca. T. nelsonii Hydrate Ridge Bud S10 genome was similar to marine sister taxa within the family Beggiatoaceae. However, the Bud S10 genome contains genes suggestive of the genetic potential for lithotrophic growth on arsenite and perhaps hydrogen. The genome also revealed that Bud S10 likely respires nitrate via two pathways: a complete denitrification pathway and a dissimilatory nitrate reduction to ammonia pathway. Both pathways have been predicted, but not previously fully elucidated, in the genomes of other large, vacuolated, sulfur-oxidizing bacteria.Surprisingly, the genome also had a high number of unusual features for a bacterium to include the largest number of metacaspases and introns ever reported in a bacterium. Also present, are a large number of other mobile genetic elements, such as insertion sequence transposable elements and miniature inverted-repeat transposable elements (MITEs. In some cases, mobile genetic elements disrupted key genes in metabolic pathways. For example, a MITE interrupts hupL, which encodes the large subunit of the hydrogenase in hydrogen oxidation. Moreover, we detected a group I intron in one of the most critical genes in the sulfur oxidation pathway, dsr

Development of field-applicable tests for rapid and sensitive detection of Candidatus Phytoplasma oryzae.

Science.gov (United States)

Wambua, Lillian; Schneider, Bernd; Okwaro, Allan; Wanga, Joseph Odhiambo; Imali, Olive; Wambua, Peninah Nduku; Agutu, Lavender; Olds, Cassandra; Jones, Chris Stephen; Masiga, Daniel; Midega, Charles; Khan, Zeyaur; Jores, Joerg; Fischer, Anne

2017-10-01

Napier grass Stunt Disease (NSD) is a severe disease of Napier grass (Pennisetum purpureum) in Eastern Africa, caused by the leafhopper-transmitted bacterium Candidatus Phytoplasma oryzae. The pathogen severely impairs the growth of Napier grass, the major fodder for dairy cattle in Eastern Africa. NSD is associated with biomass losses of up to 70% of infected plants. Diagnosis of NSD is done by nested PCR targeting the phytoplasma DNA, which is difficult to perform in developing countries with little infrastructure. We report the development of an easy to use, rapid, sensitive and specific molecular assay for field diagnosis of NSD. The procedure is based on recombinase polymerase amplification and targets the imp gene encoding a pathogen-specific immunodominant membrane protein. Therefore we followed a two-step process. First we developed an isothermal DNA amplification method for real time fluorescence application and then transferred this assay to a lateral flow format. The limit of detection for both procedures was estimated to be 10 organisms. We simplified the template preparation procedure by using freshly squeezed phloem sap from Napier grass. Additionally, we developed a laboratory serological assay with the potential to be converted to a lateral flow assay. Two murine monoclonal antibodies with high affinity and specificity to the immunodominant membrane protein IMP of Candidatus Phytoplasma oryzae were generated. Both antibodies specifically reacted with the denatured or native 17 kDa IMP protein. In dot blot experiments of extracts from infected plant, phytoplasmas were detected in as little as 12,5 μg of fresh plant material. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Proteomic analysis of the purple sulfur bacterium Candidatus "Thiodictyon syntrophicum" strain Cad16^T isolated from Lake Cadagno

DEFF Research Database (Denmark)

Storelli, Nicola; Saad, Maged M.; Frigaard, Niels-Ulrik

2014-01-01

Lake Cadagno is characterised by a compact chemocline with high concentrations of purple sulfur bacteria (PSB). 2D-DIGE was used to monitor the global changes in the proteome of Candidatus "Thiodictyon syntrophicum" strain Cad16T both in the presence and absence of light. This study aimed to disc...

Revision of the genus Phaeanthus (Annonaceae)

NARCIS (Netherlands)

Mols, J.B.; Keßler, P.J.A.

2000-01-01

A revision of the genus Phaeanthus Hook.f. & Thomson (Annonaceae) is presented. The genus comprises 8 species. A key to the fruiting and/or flowering specimens of the genus is included. The genus consists of shrubs to small-sized trees from Malesia and Vietnam. It is characterised by sepals and

'Candidatus Rickettsia nicoyana': A novel Rickettsia species isolated from Ornithodoros knoxjonesi in Costa Rica.

Science.gov (United States)

Moreira-Soto, Rolando D; Moreira-Soto, Andrés; Corrales-Aguilar, Eugenia; Calderón-Arguedas, Ólger; Troyo, Adriana

2017-06-01

Rickettsiae are intracellular bacteria commonly associated with hematophagous arthropods. Most of them have been described in hard ticks, but some have been found in soft ticks. Here we report the detection and isolation of a new Rickettsia from Ornithodoros knoxjonesi larvae collected from Balantiopteryx plicata (Emballonuridae) in Nicoya, Costa Rica. Two ticks were processed to detect Rickettsia spp. genes gltA, ompA, ompB, and htrA by PCR. Part of the macerate was also inoculated into Vero E6 and C6/36 cell lines, and cells were evaluated by Giménez stain, indirect immunofluorescence assay (IFA), and PCR. Both ticks were positive by PCR and rickettsial growth was successful in Vero E6 cells. Amplification and sequencing of near full length rrs, gltA, sca4 genes, and fragments of ompA and ompB showed that the Rickettsia sp. was different from described species. The highest homologies were with 'Candidatus Rickettsia wissemanii' and Rickettsia peacockii: 99.70% (1321/1325) with both sequences for rrs, 99.58% (1172/1177) and 99.76% (1246/1249) for gltA, 99.26% with both sequences (2948/2970 and 2957/2979) for sca4, 98.78% (485/491) and 98.39% (2069/2115) for ompA, and 98.58 (1453/1474) and 98.92% (1459/1475) for ompB; respectively. Bat blood, spleen, liver, and lung samples analyzed for Rickettsia detection were negative. Results demonstrate that the Rickettsia isolated from O. knoxjonesi is probably an undescribed species that belongs to the spotted fever group, for which 'Candidatus Rickettsia nicoyana' is proposed. Considering that B. plicata inhabits areas where contact with humans may occur and that human parasitism by Ornithodoros has been reported in the country, it will be important to continue with the characterization of this species and its pathogenic potential. Copyright © 2017 Elsevier GmbH. All rights reserved.

On the concordance genus of topologically slice knots

OpenAIRE

Hom, Jennifer

2012-01-01

The concordance genus of a knot K is the minimum Seifert genus of all knots smoothly concordant to K. Concordance genus is bounded below by the 4-ball genus and above by the Seifert genus. We give a lower bound for the concordance genus of K coming from the knot Floer complex of K. As an application, we prove that there are topologically slice knots with 4-ball genus equal to one and arbitrarily large concordance genus.

Genome sequence of "Candidatus Mycoplasma haemolamae" strain purdue, a red blood cell pathogen of alpacas (Vicugna pacos) and llamas (Lama glama).

Science.gov (United States)

Guimaraes, Ana M S; Toth, Balazs; Santos, Andrea P; do Nascimento, Naíla C; Kritchevsky, Janice E; Messick, Joanne B

2012-11-01

We report the complete genome sequence of "Candidatus Mycoplasma haemolamae," an endemic red-cell pathogen of camelids. The single, circular chromosome has 756,845 bp, a 39.3% G+C content, and 925 coding sequences (CDSs). A great proportion (49.1%) of these CDSs are organized into paralogous gene families, which can now be further explored with regard to antigenic variation.

Potential economic pests of solanaceous crops: a new species of Solanum-feeding psyllid from Australia and first record from New Zealand of Acizzia solanicola (Hemiptera: Psyllidae).

Science.gov (United States)

Taylor, Gary S; Kent, Deborah S

2013-02-11

Acizzia credoensis sp. n. is described from a single population on the native plant, Solanum lasiophyllum, from semi-arid Western Australia. The host range of Acizzia solanicola Kent & Taylor, initially recorded as damaging eggplant, S. melongena, in commercial crops and gardens and on wild tobacco bush, S. mauritianum in eastern Australia, is expanded to include the following Solanaceae: rock nightshade, S. petrophilum, cape gooseberry, Physalis peruviana, and an undetermined species of angel's trumpet Brugmansia and Datura. New Zealand specimens of A. solanicola collected in early 2012 from S. mauritianum are the first record for this species from outside Australia, and possibly represent a very recent incursion. The potential for the solanaceous-inhabiting Psyllidae to vector Candidatus Liberibacter solanacearum, an economically important plant pathogen, on native Australian Solanaceae is discussed. The occurrence of A. credoensis and A. solanicola on native Australian Solanum supports the Australian origin for the solanaceous-inhabiting Acizzia psyllids.

Weedy hosts and prevalence of potential leafhopper vectors (Hemiptera: Cicadellidae) of a phytoplasma (16SrIX group) associated with Huanglongbing symptoms in citrus groves.

Science.gov (United States)

Marques, R N; Teixeira, D C; Yamamoto, P T; Lopes, J R S

2012-04-01

Huanglongbing (HLB) is a severe citrus (Citrus spp.) disease associated with the bacteria genus Candidatus Liberibacter, detected in Brazil in 2004. Another bacterium was found in association with HLB symptoms and characterized as a phytoplasma belonging to the 16SrIX group. The objectives of this study were to identify potential leafhopper vectors of the HLB-associated phytoplasma and their host plants. Leafhoppers were sampled every other week for 12 mo with sticky yellow cards placed at two heights (0.3 and 1.5 m) in the citrus tree canopy and by using a sweep net in the ground vegetation of two sweet orange, Citrus sinensis (L.) Osbeck, groves infected by the HLB-phytoplasma in São Paulo state. Faunistic analyses indicated one Agalliinae (Agallia albidula Uhler) and three Deltocephalinae [Balclutha hebe (Kirkaldy), Planicephalus flavicosta (Stål), and Scaphytopius (Convelinus) marginelineatus (Stål)] species, as the most abundant and frequent leafhoppers (Hemiptera: Cicadellidae). Visual observations indicated an association of leafhopper species with some weeds and the influence of weed species composition on leafhopper abundance in low-lying vegetation. S. marginelineatus and P. flavicosta were more frequent on Sida rhombifolia L. and Althernantera tenella Colla, respectively, whereas A. albidula was observed more often on Conyza bonariensis (L.) Cronq. and B. hebe only occurred on grasses. DNA samples of field-collected S. marginelineatus were positive by polymerase chain reaction and sequencing tests for the presence of the HLB-phytoplasma group, indicating it as a potential vector. The association of leafhoppers with their hosts may be used in deciding which management strategies to adopt against weeds and diseases in citrus orchards.

The genus Vitex: A review

OpenAIRE

Rani, Anita; Sharma, Anupam

2013-01-01

The review includes 161 references on the genus Vitex, and comprises ethnopharmacology, morphology and microscopy, phytoconstituents, pharmacological reports, clinical studies, and toxicology of the prominent species of Vitex. Essential oils, flavonoids, iridoid glycosides, diterpenoides and ligans constitute major classes of phytoconstituents of the genus. A few species of this genus have medicinal value, among these, leaves and fruits of V. agnus-castus Linn. (Verbenaceae) has been traditio...

NSR superstring measures in genus 5

International Nuclear Information System (INIS)

Dunin-Barkowski, Petr; Sleptsov, Alexey; Stern, Abel

2013-01-01

Currently there are two proposed ansätze for NSR superstring measures: the Grushevsky ansatz and the OPSMY ansatz, which for genera g⩽4 are known to coincide. However, neither the Grushevsky nor the OPSMY ansatz leads to a vanishing two-point function in genus four, which can be constructed from the genus five expressions for the respective ansätze. This is inconsistent with the known properties of superstring amplitudes. In the present paper we show that the Grushevsky and OPSMY ansätze do not coincide in genus five. Then, by combining these ansätze, we propose a new ansatz for genus five, which now leads to a vanishing two-point function in genus four. We also show that one cannot construct an ansatz from the currently known forms in genus 6 that satisfies all known requirements for superstring measures

Genome Sequence of “Candidatus Mycoplasma haemolamae” Strain Purdue, a Red Blood Cell Pathogen of Alpacas (Vicugna pacos) and Llamas (Lama glama)

OpenAIRE

Guimaraes, Ana M. S.; Toth, Balazs; Santos, Andrea P.; do Nascimento, Naíla C.; Kritchevsky, Janice E.; Messick, Joanne B.

2012-01-01

We report the complete genome sequence of “Candidatus Mycoplasma haemolamae,” an endemic red-cell pathogen of camelids. The single, circular chromosome has 756,845 bp, a 39.3% G+C content, and 925 coding sequences (CDSs). A great proportion (49.1%) of these CDSs are organized into paralogous gene families, which can now be further explored with regard to antigenic variation.

Monomorphic pathogens: The case of Candidatus Xenohaliotis californiensis from abalone in California, USA and Baja California, Mexico.

Science.gov (United States)

Cicala, Francesco; Moore, James D; Cáceres-Martínez, Jorge; Del Río-Portilla, Miguel A; Hernández-Rodríguez, Mónica; Vásquez-Yeomans, Rebeca; Rocha-Olivares, Axayácatl

2018-05-01

Withering syndrome (WS) is a chronic wasting disease affecting abalone species attributed to the pathogen Candidatus Xenohaliotis californiensis (CXc). Wild populations of blue (Haliotis fulgens) and yellow (H. corrugata) abalone have experienced unusual mortality rates since 2009 off the peninsula of Baja California and WS has been hypothesized as a possible cause. Currently, little information is available about the genetic diversity of CXc and particularly the possible existence of strains differing in pathogenicity. In a recent phylogenetic analysis, we characterized five coding genes from this rickettsial pathogen. Here, we analyze those genes and two additional intergenic non-coding regions following multi-locus sequence typing (MLST) and multi-spacer typing (MST) approaches to assess the genetic variability of CXc and its relationship with blue, yellow and red (H. rufescens) abalone. Moreover, we used 16S rRNA pyrosequencing reads from gut microbiomes of blue and yellow abalone to complete the genetic characterization of this prokaryote. The presence of CXc was investigated in more than 150 abalone of the three species; furthermore, a total of 385 DNA sequences and 7117 16S rRNA reads from Candidatus Xenohaliotis californiensis were used to evaluate its population genetic structure. Our findings suggest the absence of polymorphism in the DNA sequences of analyzed loci and the presence of a single lineage of CXc infecting abalone from California (USA) and Baja California (Mexico). We posit that the absence of genetic variably in this marine rickettsia may be the result of evolutionary and ecological processes. Copyright © 2018 Elsevier Inc. All rights reserved.

The elliptic genus and Hidden symmetry

International Nuclear Information System (INIS)

Jaffe, A.

2001-01-01

We study the elliptic genus (a partition function) in certain interacting, twist quantum field theories. Without twists, these theories have N=2 supersymmetry. The twists provide a regularization, and also partially break the supersymmetry. In spite of the regularization, one can establish a homotopy of the elliptic genus in a coupling parameter. Our construction relies on a priori estimates and other methods from constructive quantum field theory; this mathematical underpinning allows us to justify evaluating the elliptic genus at one endpoint of the homotopy. We obtain a version of Witten's proposed formula for the elliptic genus in terms of classical theta functions. As a consequence, the elliptic genus has a hidden SL(2,Z) symmetry characteristic of conformal theory, even though the underlying theory is not conformal. (orig.)

Genome Sequence of “Candidatus Mycoplasma haemolamae” Strain Purdue, a Red Blood Cell Pathogen of Alpacas (Vicugna pacos) and Llamas (Lama glama)

Science.gov (United States)

Toth, Balazs; Santos, Andrea P.; do Nascimento, Naíla C.; Kritchevsky, Janice E.

2012-01-01

We report the complete genome sequence of “Candidatus Mycoplasma haemolamae,” an endemic red-cell pathogen of camelids. The single, circular chromosome has 756,845 bp, a 39.3% G+C content, and 925 coding sequences (CDSs). A great proportion (49.1%) of these CDSs are organized into paralogous gene families, which can now be further explored with regard to antigenic variation. PMID:23105057

Chemodiversity in the genus Aspergillus

DEFF Research Database (Denmark)

Frisvad, Jens Christian; Larsen, Thomas Ostenfeld

2015-01-01

to be characterized. The genus Aspergillus is cladistically holophyletic but phenotypically polythetic and very diverse and is associated to quite different sexual states. Following the one fungus one name system, the genus Aspergillus is restricted to a holophyletic clade that include the morphologically different...... biosynthetic family isoextrolites. However, it appears that secondary metabolites from one Aspergillus section have analogous metabolites in other sections (here also called heteroisoextrolites). In this review, we give a genus-wide overview of secondary metabolite production in Aspergillus species. Extrolites...

Models of genus one curves

OpenAIRE

Sadek, Mohammad

2010-01-01

In this thesis we give insight into the minimisation problem of genus one curves defined by equations other than Weierstrass equations. We are interested in genus one curves given as double covers of P1, plane cubics, or complete intersections of two quadrics in P3. By minimising such a curve we mean making the invariants associated to its defining equations as small as possible using a suitable change of coordinates. We study the non-uniqueness of minimisations of the genus one curves des...

'Candidatus Mycoplasma haemobos': Transplacental transmission in dairy cows (Bos taurus).

Science.gov (United States)

Girotto-Soares, Aline; Soares, João Fabio; Bogado, Alexey Leon Gomel; de Macedo, César Augusto Barbosa; Sandeski, Lígia Mara; Garcia, João Luis; Vidotto, Odilon

2016-11-15

'Candidatus Mycoplasma haemobos' is a haemotropic mycoplasma that can produce various clinical signs in cattle, but abortive potential of the parasite is unknown, as well as the frequency of transplacental transmission in cattle. Thus, the objective of this work was to evaluate the frequency of detection of 'C. M. haemobos' in aborted fetuses and the blood of dairy cows. Blood samples of 22 dairy cows that aborted and pool tissues (brain, lung, heart and liver) of their respective aborted fetuses were tested by conventional PCR. The occurrence of 'C. M. haemobos' DNA in adult animals was 40.9% (9/22) and in the fetuses was 18.2% (4/22). Two fetuses that contained 'C. M. haemobos' DNA were derived from cows which were PCR negative. When stratifying by breed, it was observed that Jersey cows had a higher proportion of positive animals (8/11; 72.7%) as compared to Holstein (1/9; 11.1% P<0.01). The results of this study suggest that this parasite can be transferred via the placenta, but it is not certain if the abortions were due to 'C. M. haemobos'. Copyright © 2016 Elsevier B.V. All rights reserved.

An updated review on the Oenothera genus.

Science.gov (United States)

Singh, Sumitra; Kaur, Rupinder; Sharma, Surendra Kr

2012-07-01

Oenothera genus (Onagraceae) has been used as a folk remedy since ancient times for the treatment of asthma, gastrointestinal disorders, neuralgia, skin diseases, and hepatic and kidney diseases. Different chemical constituents like lipids, flavonoids, tannins, steroids and triterpenes have been isolated from this genus. The various notable pharmacological activities reported from the genus are antioxidant, cytotoxic, antibacterial, antiviral, anti-inflammatory, antihyperlipidaemic, thrombolytic and antidiarrhoeal. The present paper is to summarize the worldwide reported biological activities and phytoconstituents associated with this genus for about 50 years and highlight the medicinally important species belonging to this genus so that these species can be further explored and used as therapeutic agents for various diseases.

Effect of Abscission Zone Formation on Orange ( Citrus sinensis) Fruit/Juice Quality for Trees Affected by Huanglongbing (HLB).

Science.gov (United States)

Baldwin, Elizabeth; Plotto, Anne; Bai, Jinhe; Manthey, John; Zhao, Wei; Raithore, Smita; Irey, Mike

2018-03-21

Orange trees affected by huanglongbing (HLB) exhibit excessive fruit drop, and fruit loosely attached to the tree may have inferior flavor. Fruit were collected from healthy and HLB-infected ( Candidatus liberibacter asiaticus) 'Hamlin' and 'Valencia' trees. Prior to harvest, the trees were shaken, fruit that dropped collected, tree-retained fruit harvested, and all fruit juiced. For chemical analyses, sugars and acids were generally lowest in HLB dropped (HLB-D) fruit juice compared to nonshaken healthy (H), healthy retained (H-R), and healthy dropped fruit (H-D) in early season (December) but not for the late season (January) 'Hamlin' or 'Valencia' except for sugar/acid ratio. The bitter limonoids, many flavonoids, and terpenoid volatiles were generally higher in HLB juice, especially HLB-D juice, compared to the other samples. The lower sugars, higher bitter limonoids, flavonoids, and terpenoid volatiles in HLB-D fruit, loosely attached to the tree, contributed to off-flavor, as was confirmed by sensory analyses.

How clonal is clonal? Genome plasticity across multicellular segments of a "Candidatus Marithrix sp." filament from sulfidic, briny seafloor sediments in the Gulf of Mexico

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Verena Salman-Carvalho

2016-08-01

Full Text Available Candidatus Marithrix is a recently described lineage within the group of large sulfur bacteria (Beggiatoaceae, Gammaproteobacteria. This group of bacteria comprises vacuolated, attached-living filaments that inhabit the sediment surface around vent and seep sites in the marine environment. A single filament is ca. 100 µm in diameter, several millimeters long, and consists of hundreds of clonal cells, which are considered highly polyploid. Based on these characteristics, Candidatus Marithrix was used as a model organism for the assessment of genomic plasticity along segments of a single filament using next generation sequencing to possibly identify hotspots of microevolution. Using six consecutive segments of a single filament sampled from a mud volcano in the Gulf of Mexico, we recovered ca. 90% of the Candidatus Marithrix genome in each segment. There was a high level of genome conservation along the filament with average nucleotide identities between 99.98-100%. Different approaches to assemble all reads into a complete consensus genome could not fill the gaps. Each of the six segment datasets encoded merely a few hundred unique nucleotides and 5 or less unique genes - the residual content was redundant in all datasets. Besides the overall high genomic identity, we identified a similar number of single nucleotide polymorphisms (SNPs between the clonal segments, which are comparable to numbers reported for other clonal organisms. An increase of SNPs with greater distance of filament segments was not observed. The polyploidy of the cells was apparent when analyzing the heterogeneity of reads within a segment. Here, a strong increase in single nucleotide variants, or 'intrasegmental sequence heterogeneity' (ISH events, was observed. These sites may represent hotspots for genome plasticity, and possibly microevolution, since two thirds of these variants were not co-localized across the genome copies of the multicellular filament.

Transfer of Methanolobus siciliae to the genus Methanosarcina, naming it Methanosarcina siciliae, and emendation of the genus Methanosarcina

Science.gov (United States)

Ni, S.; Woese, C. R.; Aldrich, H. C.; Boone, D. R.

1994-01-01

A sequence analysis of the 16S rRNA of Methanolobus siciliae T4/M(T) (T = type strain) showed that this strain is closely related to members of the genus Methanosarcina, especially Methanosarcina acetivorans C2A(T). Methanolobus siciliae T4/M(T) and HI350 were morphologically more similar to members of the genus Methanosarcina than to members of the genus Methanolobus in that they both formed massive cell aggregates with pseudosarcinae. Thus, we propose that Methanolobus siciliae should be transferred to the genus Methanosarcina as Methanosarcina siciliae.

Biodiversity of the genus Cladophialophora

NARCIS (Netherlands)

Badali, H.; Gueidan, C.; Najafzadeh, M.J.; Bonifaz, A.; Gerrits van den Ende, A.H.G.; de Hoog, G.S.

2008-01-01

Cladophialophora is a genus of black yeast-like fungi comprising a number of clinically highly significant species in addition to environmental taxa. The genus has previously been characterized by branched chains of ellipsoidal to fusiform conidia. However, this character was shown to have evolved

THE GENUS CULLENIA Wight * (Bombacaceae

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A. J. G. H. KOSTERMANS

1956-12-01

Full Text Available The monotypic genus Cullenia was established by Wight (IconesPI. Ind. or. 5 (1 : pi. 1761—62 & text, 1851, who differentiated it fromDurio Adans. mainly by the lack of a corolla and the position and shapeof the anthers. The only species, originally described as Durio ceylanicusby Gardner, was cited by Wight as Cullenia excelsa Wight. K. Schumanncorrected the specific epithet rather casually and atributed it (wronglyto Wight. Bentham (in Benth. & Hook., Gen. pi. 1: 212. 1867; Baillon(Hist. pi. 4: 159. 1872, Masters (in Hook, f., Fl. Br. Ind. 1: 350. 1874and Beccari (Malesia 3: 219. 1889 accepted the genus.Bakhuizen van den Brink (in Bull. Jard. bot. Buitenzorg III, 6: 228.1924 incorporated the genus in Durio.In my opinion Cullenia represents a "good" genus by its lack ofcorolla. Alston, although accepting Bakhuizen's reduction, informed mepersonally, that he, too, is inclined to consider Cullenia different fromDurio.The pollen were described as being naked and pedicellate by Gardner;this wrong statement was corrected by Wight; the anthers are pedicellateand one-celled.In this paper a new Cullenia species is described, which strengthensthe position of the genus; both species are restricted to the rain forestregion of Ceylon and the Southern Indian Peninsula.

Genus Pouteria: chemistry and biological activity

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Cíntia A. M. Silva

Full Text Available The genus Pouteria belongs to the family Sapotaceae and can be widely found around the World. These plants have been used as building material, as food, because the eatable fruits, as well as remedies in folk medicine. Some biological activities have been reported to species of this genus such as antioxidant, anti-inflammatory, antibacterial and antifungal. However, the real potential of this genus as source of new drugs or phytomedicines remains unknown. Therefore, a review of the so far known chemical composition and biological activities of this genus is presented to stimulate new studies about the species already reported moreover that species have no reference about chemistry or biological activities could be found until now.

An abundant 'Candidatus Phytoplasma solani' tuf b strain is associated with grapevine, stinging nettle and Hyalesthes obsoletus.

Science.gov (United States)

Aryan, A; Brader, G; Mörtel, J; Pastar, M; Riedle-Bauer, M

2014-10-01

Bois noir (BN) associated with ' Candidatus Phytoplasma solani' (Stolbur) is regularly found in Austrian vine growing regions. Investigations between 2003 and 2008 indicated sporadic presence of the confirmed disease vector Hyalesthes obsoletus and frequent infections of bindweed and grapevine. Infections of nettles were rare. In contrast present investigations revealed a mass occurrence of H. obsoletus almost exclusively on stinging nettle. The high population densities of H. obsoletus on Urtica dioica were accompanied by frequent occurrence of ' Ca. P. solani' in nettles and planthoppers. Sequence analysis of the molecular markers secY, stamp, tuf and vmp1 of stolbur revealed a single genotype named CPsM4_At1 in stinging nettles and more than 64 and 90 % abundance in grapevine and H. obsoletus , respectively. Interestingly, this genotype showed tuf b type restriction pattern previously attributed to bindweed associated ' Ca. P. solani' strains, but a different sequence assigned as tuf b2 compared to reference tuf b strains. All other marker genes of CPsM4_At1 clustered with tuf a and nettle derived genotypes verifying distinct nettle phytoplasma genotypes. Transmission experiments with H. obsoletus and Anaceratagallia ribauti resulted in successful transmission of five different strains including the major genotype to Catharanthus roseus and in transmission of the major genotype to U. dioica . Altogether, five nettle and nine bindweed associated genotypes were described. Bindweed types were verified in 34 % of grapevine samples, in few positive Reptalus panzeri , rarely in bindweeds and occasionally in Catharanthus roseus infected by H. obsoletus or A. ribauti . ' Candidatus Phytoplasma convolvuli' (bindweed yellows) was ascertained in nettle and bindweed samples.

The genus Vitex: A review.

Science.gov (United States)

Rani, Anita; Sharma, Anupam

2013-07-01

The review includes 161 references on the genus Vitex, and comprises ethnopharmacology, morphology and microscopy, phytoconstituents, pharmacological reports, clinical studies, and toxicology of the prominent species of Vitex. Essential oils, flavonoids, iridoid glycosides, diterpenoides and ligans constitute major classes of phytoconstituents of the genus. A few species of this genus have medicinal value, among these, leaves and fruits of V. agnus-castus Linn. (Verbenaceae) has been traditionally used in treatment of women complaints. V. agnus-castus has also been included in herbal remedies, which are in clinical use to regulate the menstrual cycle, reduce premenstrual symptom tension and anxiety, treat some menopausal symptoms as well as to treat hormonally induced acne. Despite a long tradition of use of some species, the genus has not been explored properly. In the concluding part, the future scope of Vitex species has been emphasized with a view to establish their multifarious biological activities and mode of action.

Molecular Signatures and Phylogenomic Analysis of the Genus Burkholderia: Proposal for Division of this Genus into the Emended Genus Burkholderia Containing Pathogenic Organisms and a New Genus Paraburkholderia gen. nov. Harboring Environmental Species

Directory of Open Access Journals (Sweden)

Aman eSawana

2014-12-01

Full Text Available The genus Burkholderia contains large number of diverse species which are not reliably distinguished by the available biochemical or molecular characteristics. We report here results of detailed phylogenetic and comparative genomic analyses of 45 sequenced species of the genus Burkholderia. In phylogenetic trees based upon concatenated sequences for 21 conserved proteins as well as 16S rRNA gene sequences, Burkholderia species grouped into two major clades. Within these main clades a number of smaller clades were also clearly distinguished. Our comparative analysis of protein sequences from Burkholderia spp. has identified 42 highly specific molecular markers in the form of conserved sequence indels (CSIs that are uniquely found in different clades of Burkholderia spp. Six of these CSIs are specific for a group of Burkholderia spp. (referred to as Clade I which contains all clinically relevant members of the genus as well as the phytopathogenic Burkholderia species. The second main clade (Clade II composed of the environmental Burkholderia species, is also distinguished by 2 of the identified CSIs. Additionally, our work has also identified 3 CSIs that are specific for the Burkholderia cepacia complex, 4 CSIs that are uniquely found in the Burkholderia pseudomallei group, 5 CSIs that are specific for the phytopathogenic Burkholderia spp. and 22 other CSI that distinguish two groups within Clade II. The described molecular markers provide highly specific means for the demarcation of different groups of Burkholderia spp. and for development of novel diagnostic assays for the clinically important members of the group. Based upon the results from different lines of studies, a division of the genus Burkholderia into two genera is proposed. In this new proposal, the emended genus Burkholderia will contain only the clinically relevant and phytopathogenic Burkholderia species, whereas all other Burkholderia spp. are transferred to a new genus

Molecular diversity of bacterial endosymbionts associated with dagger nematodes of the genus Xiphinema (Nematoda: Longidoridae) reveals a high degree of phylogenetic congruence with their host.

Science.gov (United States)

Palomares-Rius, Juan E; Archidona-Yuste, Antonio; Cantalapiedra-Navarrete, Carolina; Prieto, Pilar; Castillo, Pablo

2016-12-01

Bacterial endosymbionts have been detected in some groups of plant-parasitic nematodes, but few cases have been reported compared to other groups in the phylum Nematoda, such as animal-parasitic or free-living nematodes. This study was performed on a wide variety of plant-parasitic nematode families and species from different host plants and nematode populations. A total of 124 nematode populations (previously identified morphologically and molecularly) were screened for the presence of potential bacterial endosymbionts using the partial 16S rRNA gene and fluorescence in situ hybridization (FISH) and confocal microscopy. Potential bacterial endosymbionts were only detected in nematode species belonging to the genus Xiphinema and specifically in the X. americanum group. Fifty-seven partial 16S rRNA sequences were obtained from bacterial endosymbionts in this study. One group of sequences was closely related to the genus 'Candidatus Xiphinematobacter' (19 bacterial endosymbiont sequences were associated with seven nematode host species, including two that have already been described and three unknown bacterial endosymbionts). The second bacterial endosymbiont group (38 bacterial endosymbiont sequences associated with six nematode species) was related to the family Burkholderiaceae, which includes fungal and soil-plant bacterial endosymbionts. These endosymbionts were reported for the first time in the phylum Nematoda. Our findings suggest that there is a highly specific symbiotic relationship between nematode host and bacterial endosymbionts. Overall, these results were corroborated by a phylogeny of nematode host and bacterial endosymbionts that suggested that there was a high degree of phylogenetic congruence and long-term evolutionary persistence between hosts and endosymbionts. © 2016 John Wiley & Sons Ltd.

Genus Ranges of 4-Regular Rigid Vertex Graphs.

Science.gov (United States)

Buck, Dorothy; Dolzhenko, Egor; Jonoska, Nataša; Saito, Masahico; Valencia, Karin

2015-01-01

A rigid vertex of a graph is one that has a prescribed cyclic order of its incident edges. We study orientable genus ranges of 4-regular rigid vertex graphs. The (orientable) genus range is a set of genera values over all orientable surfaces into which a graph is embedded cellularly, and the embeddings of rigid vertex graphs are required to preserve the prescribed cyclic order of incident edges at every vertex. The genus ranges of 4-regular rigid vertex graphs are sets of consecutive integers, and we address two questions: which intervals of integers appear as genus ranges of such graphs, and what types of graphs realize a given genus range. For graphs with 2 n vertices ( n > 1), we prove that all intervals [ a, b ] for all a genus ranges. For graphs with 2 n - 1 vertices ( n ≥ 1), we prove that all intervals [ a, b ] for all a genus ranges. We also provide constructions of graphs that realize these ranges.

A Novel Rickettsia Species Detected in Vole Ticks (Ixodes angustus) from Western Canada

Science.gov (United States)

Anstead, Clare A.

2013-01-01

The genomic DNA of ixodid ticks from western Canada was tested by PCR for the presence of Rickettsia. No rickettsiae were detected in Ixodes sculptus, whereas 18% of the I. angustus and 42% of the Dermacentor andersoni organisms examined were PCR positive for Rickettsia. The rickettsiae from each tick species were characterized genetically using multiple genes. Rickettsiae within the D. andersoni organisms had sequences at four genes that matched those of R. peacockii. In contrast, the Rickettsia present within the larvae, nymphs, and adults of I. angustus had novel DNA sequences at four of the genes characterized compared to the sequences available from GenBank for all recognized species of Rickettsia and all other putative species within the genus. Phylogenetic analyses of the sequence data revealed that the rickettsiae in I. angustus do not belong to the spotted fever, transitional, or typhus groups of rickettsiae but are most closely related to “Candidatus Rickettsia kingi” and belong to a clade that also includes R. canadensis, “Candidatus Rickettsia tarasevichiae,” and “Candidatus Rickettsia monteiroi.” PMID:24077705

A review of the genus Erycibe Roxb

NARCIS (Netherlands)

Hoogland, R.D.

1953-01-01

In this paper I intend to give a review of the genus Erycibe Roxb. in. which all the names published in the genus will be accounted for. The representatives from Malaysia have been dealt with more extensively in the revision of the genus in Flora Malesiana, Ser. I, Vol. 4, 4th instalment, 1953, pp.

Revised concept of the fossil genus Oviparosiphum Shaposhnikov, 1979 with the description of a new genus (Hemiptera, Sternorrhyncha, Aphidomorpha

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Dagmara Żyła

2015-02-01

Full Text Available This paper presents a revision of the aphid genus Oviparosiphum, which is known from the Cretaceous period. Redescriptions of two species: O. jakovlevi Shaposhnikov, 1979 and O. baissense Shaposhnikov & Wegierek, 1989 are made, and an updated diagnosis of this genus is provided. Oviparosiphum baissense is the type species of a newly described genus Archeoviparosiphum gen. n. Five other species of Oviparosiphum are also transferred to the new genus. The basis for their separation from Oviparosiphum is the structure of the siphunculi and ovipositor. A key is provided to the genera of Oviparosiphidae.

2+1 gravity for genus >1

International Nuclear Information System (INIS)

Nelson, J.E.; Regge, T.

1991-01-01

We analysed the algebra of observables for the simple case of a genus 1 initial data surface Σ 2 for 2+1 De Sitter gravity. Here we extend the analysis to higher genus. We construct for genus 2 the group of automorphisms H of the homotopy group π 1 induced by the mapping class group. The group H induces a group D of canonical transformations on the algebra of observables which is related to the braid group for 6 threads. (orig.)

Symbiotic diversity in the cosmopolitan genus Acacia

Science.gov (United States)

James K. Leary; Paul W. Singleton; Paul G. Scowcroft; Dulal Borthakur

2006-01-01

Acacia is the second largest genus within the Leguminosae, with 1352 species identified. This genus is now known to be polyphyletic and the international scientific community will presumably split Acacia into five new genera. This review examines the diversity of biological nitrogen fixation symbiosis within Acacia as a single genus. Due to its global importance, an...

Genus-two characters of the Ising model

International Nuclear Information System (INIS)

Choi, J.H.; Koh, I.G.

1989-01-01

As a first step in studying conformal theories on a higher-genus Riemann surface, we construct genus-two characters of the Ising model from their behavior in zero- and nonzero-homology pinching limits, the Goddard-Kent-Oliveco set-space construction, and the branching coefficients in the level-two A 1 /sup (1)/ Kac-Moody characters on the higher-genus Riemann surface

Heterogeneity in the genus Allovahlkampfia and the description of the new genus Parafumarolamoeba (Vahlkampfiidae; Heterolobosea).

Science.gov (United States)

Geisen, Stefan; Bonkowski, Michael; Zhang, Junling; De Jonckheere, Johan F

2015-08-01

Heterolobosean amoebae are common and diverse members of soil protist communities. In this study, we isolated seven strains of amoebae from soil samples taken in Tibet (at high altitude), Sardinia and the Netherlands, all resembling to belong to a similar heterolobosean morphospecies. However, sequences of the small subunit (SSU) rDNA and internal transcribed spacers, including the 5.8S rDNA, revealed a high heterogeneity in the genus Allovahlkampfia to which six of the isolates belong. Some unnamed strains, of which the sequences had been published before, are also included within the genus Allovahlkampfia. One Allovahlkampfia isolated in the Netherlands harbors a twin-ribozyme, containing a His-Cys box, similar to the one found in strain BA of Allovahlkampfia. The other SSU rDNA sequence grouped in phylogenetic analyses with sequences obtained in environmental sequencing studies as sister to the genus Fumarolamoeba. This phylogenetic placement was supported by analyses of the 5.8S rDNA leading us to describe it as a new genus Parafumarolamoeba. Copyright © 2015 Elsevier GmbH. All rights reserved.

Candidatus Rickettsia andeanae, a spotted fever group agent infecting Amblyomma parvum ticks in two Brazilian biomes

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Fernanda Aparecida Nieri-Bastos

2014-04-01

Full Text Available Adult ticks of the species Amblyomma parvum were collected from the vegetation in the Pantanal biome (state of Mato Grosso do Sul and from horses in the Cerrado biome (state of Piauí in Brazil. The ticks were individually tested for rickettsial infection via polymerase chain reaction (PCR targeting three rickettsial genes, gltA, ompA and ompB. Overall, 63.5% (40/63 and 66.7% (2/3 of A. parvum ticks from Pantanal and Cerrado, respectively, contained rickettsial DNA, which were all confirmed by DNA sequencing to be 100% identical to the corresponding fragments of the gltA, ompA and ompB genes of Candidatus Rickettsia andeanae. This report is the first to describe Ca. R. andeanae in Brazil.

Genus vesiculoviruses

Science.gov (United States)

The vesiculovirus genus of the family Rhabdoviridae contains a numbers of viruses that have been taxonomically classified using a combination of serological relatedness, host range, genome organization, pathobiology and phylogenetic analysis of sequence data. There are 11 viruses assigned to the gen...

The genus Isodon (Schrad. ex Benth. Spach in Africa and a new genus Rabdosiella Codd (Lamiaceae

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L. E. Codd

1984-12-01

Full Text Available The typification of the genus Isodon (Schrad. ex Benth. Spach and its occurrence in Africa are discussed; an allied genus Rabdosiella Codd is described and the combinations R. calycina (Benth. Codd and R. ternifolia (D.Don Codd (the latter an Indian species are effected.

Occurrence and importance of anaerobic ammonium-oxidising bacteria in vegetable soils.

Science.gov (United States)

Shen, Li-dong; Wu, Hong-sheng; Gao, Zhi-qiu; Xu, Xiang-hua; Chen, Tie-xi; Liu, Shuai; Cheng, Hai-xiang

2015-07-01

The quantitative importance of anaerobic ammonium oxidation (anammox) has been described in paddy fields, while the presence and importance of anammox in subsurface soil from vegetable fields have not been determined yet. Here, we investigated the occurrence and activity of anammox bacteria in five different types of vegetable fields located in Jiangsu Province, China. Stable isotope experiments confirmed the anammox activity in the examined soils, with the potential rates of 2.1 and 23.2 nmol N2 g(-1) dry soil day(-1), and the anammox accounted for 5.9-20.5% of total soil dinitrogen gas production. It is estimated that a total loss of 7.1-78.2 g N m(-2) year(-1) could be linked to the anammox process in the examined vegetable fields. Phylogenetic analyses showed that multiple co-occurring anammox genera were present in the examined soils, including Candidatus Brocadia, Candidatus Kuenenia, Candidatus Anammoxoglobus and Candidatus Jettenia, and Candidatus Brocadia appeared to be the most common anammox genus. Quantitative PCR further confirmed the presence of anammox bacteria in the examined soils, with the abundance varying from 2.8 × 10(5) to 3.0 × 10(6) copies g(-1) dry soil. Correlation analyses suggested that the soil ammonium concentration had significant influence on the activity and abundance of anammox bacteria in the examined soils. The results of our study showed the presence of diverse anammox bacteria and indicated that the anammox process could serve as an important nitrogen loss pathway in vegetable fields.

Phylogeny of the Genus Drosophila

Science.gov (United States)

O’Grady, Patrick M.; DeSalle, Rob

2018-01-01

Understanding phylogenetic relationships among taxa is key to designing and implementing comparative analyses. The genus Drosophila, which contains over 1600 species, is one of the most important model systems in the biological sciences. For over a century, one species in this group, Drosophila melanogaster, has been key to studies of animal development and genetics, genome organization and evolution, and human disease. As whole-genome sequencing becomes more cost-effective, there is increasing interest in other members of this morphologically, ecologically, and behaviorally diverse genus. Phylogenetic relationships within Drosophila are complicated, and the goal of this paper is to provide a review of the recent taxonomic changes and phylogenetic relationships in this genus to aid in further comparative studies. PMID:29716983

Effect of freshwater mussels on the vertical distribution of anaerobic ammonia oxidizers and other nitrogen-transforming microorganisms in upper Mississippi river sediment

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Ellen M. Black

2017-07-01

Full Text Available Targeted qPCR and non-targeted amplicon sequencing of 16S rRNA genes within sediment layers identified the anaerobic ammonium oxidation (anammox niche and characterized microbial community changes attributable to freshwater mussels. Anammox bacteria were normally distributed (Shapiro-Wilk normality test, W-statistic =0.954, p = 0.773 between 1 and 15 cm depth and were increased by a factor of 2.2 (p < 0.001 at 3 cm below the water-sediment interface when mussels were present. Amplicon sequencing of sediment at depths relevant to mussel burrowing (3 and 5 cm showed that mussel presence reduced observed species richness (p = 0.005, Chao1 diversity (p = 0.005, and Shannon diversity (p < 0.001, with more pronounced decreases at 5 cm depth. A non-metric, multidimensional scaling model showed that intersample microbial species diversity varied as a function of mussel presence, indicating that sediment below mussels harbored distinct microbial communities. Mussel presence corresponded with a 4-fold decrease in a majority of operational taxonomic units (OTUs classified in the phyla Gemmatimonadetes, Actinobacteria, Acidobacteria, Plantomycetes, Chloroflexi, Firmicutes, Crenarcheota, and Verrucomicrobia. 38 OTUs in the phylum Nitrospirae were differentially abundant (p < 0.001 with mussels, resulting in an overall increase from 25% to 35%. Nitrogen (N-cycle OTUs significantly impacted by mussels belonged to anammmox genus Candidatus Brocadia, ammonium oxidizing bacteria family Nitrosomonadaceae, ammonium oxidizing archaea genus Candidatus Nitrososphaera, nitrite oxidizing bacteria in genus Nitrospira, and nitrate- and nitrite-dependent anaerobic methane oxidizing organisms in the archaeal family “ANME-2d” and bacterial phylum “NC10”, respectively. Nitrosomonadaceae (0.9-fold (p < 0.001 increased with mussels, while NC10 (2.1-fold (p < 0.001, ANME-2d (1.8-fold (p < 0.001, and Candidatus Nitrososphaera (1.5-fold (p < 0

Etiology of three recent diseases of citrus in São Paulo State: sudden death, variegated chlorosis and huanglongbing.

Science.gov (United States)

Bové, Joseph Marie; Ayres, Antonio Juliano

2007-01-01

, citrus variegated chlorosis (CVC), was observed in 1987 in the Triangulo Mineiro of Minas Gerais State and the northern and north-eastern parts of SSP. By 2000, the disease affected already 34% of the 200 million sweet orange trees in SSP. By 2005, the percentage had increased to 43%, and CVC was present in all citrus growing regions of Brazil. Electron microscopy showed that xylem-limited bacteria were present in all symptomatic sweet orange leaves and fruit tissues tested, but not in similar materials from healthy, symptomless trees. Bacteria were consistently cultured from twigs of CVC-affected sweet orange trees but not from twigs of healthy trees. Serological analyses showed the CVC bacterium to be a strain of Xylella fastidiosa. The disease could be reproduced and Koch's postulates fulfilled, by mechanically inoculating a pure culture of X. fastidiosa isolate 8.1.b into sweet orange seedlings. The genome of a CVC strain of X. fastidiosa was sequenced in SSP in the frame of a project supported by FAPESP and Fundecitrus. X. fastidiosa is the first plant pathogenic bacterium, the genome of which has been sequenced. Until recently, America was free of huanglongbing (HLB), but in March 2004 and August 2005, symptoms of the disease were recognized, respectively in the State of São Paulo (SSP) and in Florida, USA. HLB was known in China since 1870 and in South Africa since 1928. Because of its destructiveness and its rapid spread by efficient psyllid insect-vectors, HLB is probably the most serious citrus disease. HLB is caused by a phloem sieve tube-restricted Gram negative bacterium, not yet available in culture. In the 1990s, the bacterium was characterized by molecular techniques as a member of the alpha proteobacteria designated Candidatus Liberibacter africanus for the disease in Africa, and Candidatus Liberibacter asiaticus for HLB in Asia. In SSP, Ca. L. asiaticus is also present, but most of the trees are infected with a new species, Candidatus Liberibacter

Phylogeny of the Peckia-genus group

DEFF Research Database (Denmark)

Buenaventura Ruiz, Ingrid Eliana; Pape, Thomas

2015-01-01

Peckia is the most species-rich necrophagous genus among the Neotropical sarcophagids, encompassing 67 species distributed in 5 subgenera. Recent phylogenetic studies have challenged the monophyly of this genus with regard to species of the genera Peckiamyia, Titanogrypa, and Villegasia, and the ...

The genus Lolium : taxonomy and genetic resources

OpenAIRE

Loos, B.P.

1994-01-01

Several aspects of variation within the genus Lolium, and more in detail within Lolium perenne (perennial ryegrass) have been highlighted. As the results are extensively discussed in each chapter, the general discussion is focused on two aspects of the research.

Speciation
It is clear that the genus Lolium is a very variable genus. The variation within the species reduces the clarity o...

Aspidonepsis (Asclepiadaceae, a new southern African genus

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A. Nicholas

1992-10-01

Full Text Available Aspidonepsis, an endemic southern African genus, is described and compared to the closely allied genus Aspidoglossum. This newly described genus is composed of two subgenera, Aspidonepsis and Unguilobium. consisting of three and two species respectively.  Asclepias diploglossa, A. flava, A. cognata and A. reneensis are transferred to Aspidonepsis. and A. shebae is newly described. All species are discussed, illustrated and a key is given to aid in their identification.

Genomes-based phylogeny of the genus Xanthomonas

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Rodriguez-R Luis M

2012-03-01

Full Text Available Abstract Background The genus Xanthomonas comprises several plant pathogenic bacteria affecting a wide range of hosts. Despite the economic, industrial and biological importance of Xanthomonas, the classification and phylogenetic relationships within the genus are still under active debate. Some of the relationships between pathovars and species have not been thoroughly clarified, with old pathovars becoming new species. A change in the genus name has been recently suggested for Xanthomonas albilineans, an early branching species currently located in this genus, but a thorough phylogenomic reconstruction would aid in solving these and other discrepancies in this genus. Results Here we report the results of the genome-wide analysis of DNA sequences from 989 orthologous groups from 17 Xanthomonas spp. genomes available to date, representing all major lineages within the genus. The phylogenetic and computational analyses used in this study have been automated in a Perl package designated Unus, which provides a framework for phylogenomic analyses which can be applied to other datasets at the genomic level. Unus can also be easily incorporated into other phylogenomic pipelines. Conclusions Our phylogeny agrees with previous phylogenetic topologies on the genus, but revealed that the genomes of Xanthomonas citri and Xanthomonas fuscans belong to the same species, and that of Xanthomonas albilineans is basal to the joint clade of Xanthomonas and Xylella fastidiosa. Genome reduction was identified in the species Xanthomonas vasicola in addition to the previously identified reduction in Xanthomonas albilineans. Lateral gene transfer was also observed in two gene clusters.

Molecular signatures and phylogenomic analysis of the genus Burkholderia: proposal for division of this genus into the emended genus Burkholderia containing pathogenic organisms and a new genus Paraburkholderia gen. nov. harboring environmental species.

Science.gov (United States)

Sawana, Amandeep; Adeolu, Mobolaji; Gupta, Radhey S

2014-01-01

The genus Burkholderia contains large number of diverse species which include many clinically important organisms, phytopathogens, as well as environmental species. However, currently, there is a paucity of biochemical or molecular characteristics which can reliably distinguish different groups of Burkholderia species. We report here the results of detailed phylogenetic and comparative genomic analyses of 45 sequenced species of the genus Burkholderia. In phylogenetic trees based upon concatenated sequences for 21 conserved proteins as well as 16S rRNA gene sequence based trees, members of the genus Burkholderia grouped into two major clades. Within these main clades a number of smaller clades including those corresponding to the clinically important Burkholderia cepacia complex (BCC) and the Burkholderia pseudomallei groups were also clearly distinguished. Our comparative analysis of protein sequences from Burkholderia spp. has identified 42 highly specific molecular markers in the form of conserved sequence indels (CSIs) that are uniquely found in a number of well-defined groups of Burkholderia spp. Six of these CSIs are specific for a group of Burkholderia spp. (referred to as Clade I in this work) which contains all clinically relevant members of the genus (viz. the BCC and the B. pseudomallei group) as well as the phytopathogenic Burkholderia spp. The second main clade (Clade II), which is composed of environmental Burkholderia species, is also distinguished by 2 identified CSIs that are specific for this group. Additionally, our work has also identified multiple CSIs that serve to clearly demarcate a number of smaller groups of Burkholderia spp. including 3 CSIs that are specific for the B. cepacia complex, 4 CSIs that are uniquely found in the B. pseudomallei group, 5 CSIs that are specific for the phytopathogenic Burkholderia spp. and 22 other CSI that distinguish two groups within Clade II. The described molecular markers provide highly specific means for

Molecular signatures and phylogenomic analysis of the genus Burkholderia: proposal for division of this genus into the emended genus Burkholderia containing pathogenic organisms and a new genus Paraburkholderia gen. nov. harboring environmental species

Science.gov (United States)

Sawana, Amandeep; Adeolu, Mobolaji; Gupta, Radhey S.

2014-01-01

The genus Burkholderia contains large number of diverse species which include many clinically important organisms, phytopathogens, as well as environmental species. However, currently, there is a paucity of biochemical or molecular characteristics which can reliably distinguish different groups of Burkholderia species. We report here the results of detailed phylogenetic and comparative genomic analyses of 45 sequenced species of the genus Burkholderia. In phylogenetic trees based upon concatenated sequences for 21 conserved proteins as well as 16S rRNA gene sequence based trees, members of the genus Burkholderia grouped into two major clades. Within these main clades a number of smaller clades including those corresponding to the clinically important Burkholderia cepacia complex (BCC) and the Burkholderia pseudomallei groups were also clearly distinguished. Our comparative analysis of protein sequences from Burkholderia spp. has identified 42 highly specific molecular markers in the form of conserved sequence indels (CSIs) that are uniquely found in a number of well-defined groups of Burkholderia spp. Six of these CSIs are specific for a group of Burkholderia spp. (referred to as Clade I in this work) which contains all clinically relevant members of the genus (viz. the BCC and the B. pseudomallei group) as well as the phytopathogenic Burkholderia spp. The second main clade (Clade II), which is composed of environmental Burkholderia species, is also distinguished by 2 identified CSIs that are specific for this group. Additionally, our work has also identified multiple CSIs that serve to clearly demarcate a number of smaller groups of Burkholderia spp. including 3 CSIs that are specific for the B. cepacia complex, 4 CSIs that are uniquely found in the B. pseudomallei group, 5 CSIs that are specific for the phytopathogenic Burkholderia spp. and 22 other CSI that distinguish two groups within Clade II. The described molecular markers provide highly specific means for

Phylogenomic analysis of Candidatus ‘Izimaplasma’ species: free-living representatives from a Tenericutes clade found in methane seeps

KAUST Repository

Skennerton, Connor T.

2016-04-08

Tenericutes are a unique class of bacteria that lack a cell wall and are typically parasites or commensals of eukaryotic hosts. Environmental 16S rDNA surveys have identified a number of tenericute clades in diverse environments, introducing the possibility that these Tenericutes may represent non-host-associated, free-living microorganisms. Metagenomic sequencing of deep-sea methane seep sediments resulted in the assembly of two genomes from a Tenericutes-affiliated clade currently known as \\'NB1-n\\' (SILVA taxonomy) or \\'RF3\\' (Greengenes taxonomy). Metabolic reconstruction revealed that, like cultured members of the Mollicutes, these \\'NB1-n\\' representatives lack a tricarboxylic acid cycle and instead use anaerobic fermentation of simple sugars for substrate level phosphorylation. Notably, the genomes also contained a number of unique metabolic features including hydrogenases and a simplified electron transport chain containing an RNF complex, cytochrome bd oxidase and complex I. On the basis of the metabolic potential predicted from the annotated genomes, we devised an anaerobic enrichment media that stimulated the growth of these Tenericutes at 10 °C, resulting in a mixed culture where these organisms represented ∼60% of the total cells by targeted fluorescence in situ hybridization (FISH). Visual identification by FISH confirmed these organisms were not directly associated with Eukaryotes and electron cryomicroscopy of cells in the enrichment culture confirmed an ultrastructure consistent with the defining phenotypic property of Tenericutes, with a single membrane and no cell wall. On the basis of their unique gene content, phylogenetic placement and ultrastructure, we propose these organisms represent a novel class within the Tenericutes, and suggest the names Candidatus \\'Izimaplasma sp. HR1\\' and Candidatus \\'Izimaplasma sp. HR2\\' for the two genome representatives.

A new name for the foraminiferal genus Heterospira

NARCIS (Netherlands)

Umbgrove, J.H.F.

1937-01-01

A short time ago I described a new foraminiferal genus from the Tertiary of Borneo 1). I gave this genus the name of Heterospira. Mr. P. H. Oehser of Washington drew my attention to the fact that E. Koken as early as 1896²) had used the name Heterospira for a genus of triassic gastropoda from

Molecular detection of ‘Candidatus Phytoplasma australasia’ and ‘Ca. P. cynodontis’ in Iraq

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Alkuwaiti Nawres Abdulelah Sadeq

2017-10-01

Full Text Available The association of phytoplasma was investigated in symptomatic tomato (Solanum lycopersicum L., eggplant (Solanum melongen L., mallow (Malva spp. and Bermuda grass (Cynodon dactylon L. plants exhibiting witches’ broom and white leaf diseases, respectively. Total DNA was extracted from tomato (n=3, eggplant (n=2, mallow (n=2 and Bermuda grass (n=8 samples. Direct polymerase chain reaction (PCR was performed using P1/P7 primer set, then PCR products were sequenced. Sequences obtained from tomato, eggplant and mallow shared 99% maximum nucleotide identity with phytoplasma belonging to subgroup 16SrII-D, and resulted therefore ‘Candidatus Phytoplasma australasia’-related. Sequences obtained from Bermuda grass showed 100% maximum nucleotide identity to 16SrXIV-A subgroup and were ‘Ca. P. cynodontis’-related. The study presents the first molecular confirmation and sequence data of presence of ‘Ca. P. australasia’ and ‘Ca. P. cynodontis’ in Iraq.

Candidatus Syngnamydia venezia, a novel member of the phylum Chlamydiae from the broad nosed pipefish, Syngnathus typhle.

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Alexander Fehr

Full Text Available Chlamydia are obligate intracellular bacteria and important pathogens of humans and animals. Chlamydia-related bacteria are also major fish pathogens, infecting epithelial cells of the gills and skin to cause the disease epitheliocystis. Given the wide distribution, ancient origins and spectacular diversity of bony fishes, this group offers a rich resource for the identification and isolation of novel Chlamydia. The broad-nosed pipefish (Syngnathus typhle is a widely distributed and genetically diverse temperate fish species, susceptible to epitheliocystis across much of its range. We describe here a new bacterial species, Candidatus Syngnamydia venezia; epitheliocystis agent of S. typhle and close relative to other chlamydial pathogens which are known to infect diverse hosts ranging from invertebrates to humans.

Comparative Genomics of Bacteriophage of the Genus Seuratvirus

DEFF Research Database (Denmark)

Sazinas, Pavelas; Redgwell, Tamsin; Rihtman, Branko

2017-01-01

polB and terL showed these bacteriophages to be closely related to members of the genus Seuratvirus. We performed a core-gene analysis using the 14 new and four closely related genomes. A total of 58 core genes were identified, the majority of which has no known function. These genes were used...... to construct a core-gene phylogeny, the results of which confirmed the new isolates to be part of the genus Seuratvirus and expanded the number of species within this genus to four. All bacteriophages within the genus contained the genes queCDE encoding enzymes involved in queuosine biosynthesis. We suggest...

Candidatus Renichlamydia lutjani, a Gram-negative bacterium in internal organs of blue striped snapper Lutjanus kasmira from Hawaii

Science.gov (United States)

Corsaro, Daniele; Work, Thierry M.

2012-01-01

The blue-striped snapper Lutjanus kasmira (Perciformes, Lutjanidae) are cosmopolitan in the Indo-Pacific but were introduced into Oahu, Hawaii, USA, in the 1950s and have since colonized most of the archipelago. Studies of microparasites in blue-striped snappers from Hawaii revealed chlamydia-like organisms (CLO) infecting the spleen and kidney, characterized by intracellular basophilic granular inclusions containing Gram-negative and Gimenez-positive bacteria similar in appearance to epitheliocysts when seen under light microscopy. We provide molecular evidence that CLO are a new member of Chlamydiae, i.e. Candidatus Renichlamydia lutjani, that represents the first reported case of chlamydial infection in organs other than the gill in fishes.

Symbiotic adaptation drives genome streamlining of the cyanobacterial sponge symbiont "Candidatus Synechococcus pongiarum"

KAUST Repository

Gao, Zhao-Ming

2014-04-01

"Candidatus Synechococcus spongiarum" is a cyanobacterial symbiont widely distributed in sponges, but its functions at the genome level remain unknown. Here, we obtained the draft genome (1.66 Mbp, 90% estimated genome recovery) of "Ca. Synechococcus spongiarum" strain SH4 inhabiting the Red Sea sponge Carteriospongia foliascens. Phylogenomic analysis revealed a high dissimilarity between SH4 and free-living cyanobacterial strains. Essential functions, such as photosynthesis, the citric acid cycle, and DNA replication, were detected in SH4. Eukaryoticlike domains that play important roles in sponge-symbiont interactions were identified exclusively in the symbiont. However, SH4 could not biosynthesize methionine and polyamines and had lost partial genes encoding low-molecular-weight peptides of the photosynthesis complex, antioxidant enzymes, DNA repair enzymes, and proteins involved in resistance to environmental toxins and in biosynthesis of capsular and extracellular polysaccharides. These genetic modifications imply that "Ca. Synechococcus spongiarum" SH4 represents a low-light-adapted cyanobacterial symbiont and has undergone genome streamlining to adapt to the sponge\\'s mild intercellular environment. 2014 Gao et al.

Symbiotic adaptation drives genome streamlining of the cyanobacterial sponge symbiont "Candidatus Synechococcus pongiarum"

KAUST Repository

Gao, Zhao-Ming; Wang, Yong; Tian, Ren-Mao; Wong, Yue Him; Batang, Zenon B.; Al-Suwailem, Abdulaziz M.; Bajic, Vladimir B.; Qian, Pei-Yuan

2014-01-01

"Candidatus Synechococcus spongiarum" is a cyanobacterial symbiont widely distributed in sponges, but its functions at the genome level remain unknown. Here, we obtained the draft genome (1.66 Mbp, 90% estimated genome recovery) of "Ca. Synechococcus spongiarum" strain SH4 inhabiting the Red Sea sponge Carteriospongia foliascens. Phylogenomic analysis revealed a high dissimilarity between SH4 and free-living cyanobacterial strains. Essential functions, such as photosynthesis, the citric acid cycle, and DNA replication, were detected in SH4. Eukaryoticlike domains that play important roles in sponge-symbiont interactions were identified exclusively in the symbiont. However, SH4 could not biosynthesize methionine and polyamines and had lost partial genes encoding low-molecular-weight peptides of the photosynthesis complex, antioxidant enzymes, DNA repair enzymes, and proteins involved in resistance to environmental toxins and in biosynthesis of capsular and extracellular polysaccharides. These genetic modifications imply that "Ca. Synechococcus spongiarum" SH4 represents a low-light-adapted cyanobacterial symbiont and has undergone genome streamlining to adapt to the sponge's mild intercellular environment. 2014 Gao et al.

Beta genus papillomaviruses and skin cancer.

Science.gov (United States)

Howley, Peter M; Pfister, Herbert J

2015-05-01

A role for the beta genus HPVs in keratinocyte carcinoma (KC) remains to be established. In this article we examine the potential role of the beta HPVs in cancer revealed by the epidemiology associating these viruses with KC and supported by oncogenic properties of the beta HPV proteins. Unlike the cancer associated alpha genus HPVs, in which transcriptionally active viral genomes are invariably found associated with the cancers, that is not the case for the beta genus HPVs and keratinocyte carcinomas. Thus a role for the beta HPVs in KC would necessarily be in the carcinogenesis initiation and not in the maintenance of the tumor. Copyright © 2015 Elsevier Inc. All rights reserved.

Refining the Roots of the Beewolf-Streptomyces Symbiosis: Antennal Symbionts in the Rare Genus Philanthinus (Hymenoptera, Crabronidae)

Science.gov (United States)

Yildirim, Erol; Gürbüz, M. Faruk; Herzner, Gudrun; Strohm, Erhard

2012-01-01

Insects engage in symbiotic associations with a large diversity of beneficial microorganisms. While the majority of well-studied symbioses have a nutritional basis, several cases are known in which bacteria protect their host from pathogen infestation. Solitary wasps of the genera Philanthus and Trachypus (beewolves; Hymenoptera, Crabronidae) cultivate the actinomycete “Candidatus Streptomyces philanthi” in specialized antennal gland reservoirs. The symbionts are transferred to the larval cocoon, where they provide protection against pathogenic fungi by producing at least nine different antibiotics. Here we investigated the closest relatives of Philanthus and Trachypus, the rare genus Philanthinus, for the presence of antennal gland reservoirs and symbiotic streptomycetes. Molecular analyses identified “Ca. Streptomyces philanthi” in reservoirs of Philanthinus quattuordecimpunctatus. Phylogenies based on the 16S rRNA gene suggest that P. quattuordecimpunctatus may have acquired “Ca. Streptomyces philanthi” by horizontal transfer from other beewolf species. In histological sections and three-dimensional reconstructions, the antennal gland reservoirs were found to occupy six antennal segments (as opposed to only five in Philanthus and Trachypus) and to be structurally less complex than those of the evolutionarily more derived genera of beewolves. The presence of “Ca. Streptomyces philanthi” in antennal glands of Philanthinus indicates that the symbiosis between beewolves and Streptomyces bacteria is much older than previously thought. It probably evolved along the branch leading to the monophyletic tribe Philanthini, as it seems to be confined to the genera Philanthus, Trachypus, and Philanthinus, which together comprise 172 described species of solitary wasps. PMID:22113914

The Representatives of Amelanchier Medik. Genus in Ukraine

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Opalko Anatoliy Ivanovich

2015-04-01

Full Text Available The information on fruit and decorative value, honey and medicinal properties of the genus Amelanchier Medik. is generalized. Their biological characteristics, chemical composition and palatability traits of the fruit, the ways of consumption and processing, including drying, preparing juices, syrups, jams, candied fruit jellies, confiture, and fruit wine are specified. The environmental adaptability and effectiveness of using juneberry for phytomelioration are mentioned. Several versions of the origin of the genus Amelanchier name and interpretation of its specific epithets are described. The controversial issues of the genus Amelanchier system were discussed from the classical and molecular genetic approaches. The attention is focused on two main aspects of views on the place of the genus Amelanchier representatives of the family Rosaceae Juss. within the particular subfamily, namely the subfamily Pyroideae Burnett (Maloideae S. Weber or the subfamily Amygdaloideae Arn., which indicates the necessity for further comparative morphological and molecular genetic studies of the family Rosaceae. The directions of evolution, habitat and invasive ability of some species of the genus Amelanchier are characterised. The list of the genus Amelanchier representatives cultivated in Ukraine is given.

Genomic diversity within the haloalkaliphilic genus Thioalkalivibrio.

Science.gov (United States)

Ahn, Anne-Catherine; Meier-Kolthoff, Jan P; Overmars, Lex; Richter, Michael; Woyke, Tanja; Sorokin, Dimitry Y; Muyzer, Gerard

2017-01-01

Thioalkalivibrio is a genus of obligate chemolithoautotrophic haloalkaliphilic sulfur-oxidizing bacteria. Their habitat are soda lakes which are dual extreme environments with a pH range from 9.5 to 11 and salt concentrations up to saturation. More than 100 strains of this genus have been isolated from various soda lakes all over the world, but only ten species have been effectively described yet. Therefore, the assignment of the remaining strains to either existing or novel species is important and will further elucidate their genomic diversity as well as give a better general understanding of this genus. Recently, the genomes of 76 Thioalkalivibrio strains were sequenced. On these, we applied different methods including (i) 16S rRNA gene sequence analysis, (ii) Multilocus Sequence Analysis (MLSA) based on eight housekeeping genes, (iii) Average Nucleotide Identity based on BLAST (ANIb) and MUMmer (ANIm), (iv) Tetranucleotide frequency correlation coefficients (TETRA), (v) digital DNA:DNA hybridization (dDDH) as well as (vi) nucleotide- and amino acid-based Genome BLAST Distance Phylogeny (GBDP) analyses. We detected a high genomic diversity by revealing 15 new "genomic" species and 16 new "genomic" subspecies in addition to the ten already described species. Phylogenetic and phylogenomic analyses showed that the genus is not monophyletic, because four strains were clearly separated from the other Thioalkalivibrio by type strains from other genera. Therefore, it is recommended to classify the latter group as a novel genus. The biogeographic distribution of Thioalkalivibrio suggested that the different "genomic" species can be classified as candidate disjunct or candidate endemic species. This study is a detailed genome-based classification and identification of members within the genus Thioalkalivibrio. However, future phenotypical and chemotaxonomical studies will be needed for a full species description of this genus.

Genomic Diversity in the Genus of Aspergillus

DEFF Research Database (Denmark)

Rasmussen, Jane Lind Nybo

, sections and genus of Aspergillus. The work uncovers a large genomic diversity across all studied groups of species. The genomic diversity was especially evident on the section level, where the proteins shared by all species only represents ⇠55% of the proteome. This number decreases even further, to 38......, sections Nigri, Usti and Cavericolus, clade Tubingensis, and species A. niger. It lastly uses these results to predict genetic traits that take part in fungal speciation. Within a few years the Aspergillus whole-genus sequencing project will have published all currently-accepted Aspergillus genomes......Aspergillus is a highly important genus of saprotrophic filamentous fungi. It is a very diverse genus that is inextricably intertwined with human a↵airs on a daily basis, holding species relevant to plant and human pathology, enzyme and bulk chemistry production, food and beverage biotechnology...

Rank Two Affine Manifolds in Genus 3

OpenAIRE

Aulicino, David; Nguyen, Duc-Manh

2016-01-01

We complete the classification of rank two affine manifolds in the moduli space of translation surfaces in genus three. Combined with a recent result of Mirzakhani and Wright, this completes the classification of higher rank affine manifolds in genus three.

Phylogenetic Analysis of the Synnema-Producing Genus Synnemapestaloides

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Kyoko Watanabe

2016-11-01

Full Text Available Synnemapestaloides rhododendri, the type species of the genus Synnemapestaloides, is a pathogen of Rhododendron brachycarpum. This fungus produces six-celled conidia with appendages at both end cells, and are generated by annellidic conidiogenous cells on the synnema. These conidial structures are similar to those of the genus Pestalotia. The monotypic genus Synnemapestaloides is currently classified in the family Amphisphaeriaceae solely based on conidial morphology. Here we demonstrate that Synnemapestaloides represents a distinct genus in the family Sporocadaceae (Amphisphaeriales based on differences in the nucleotide sequences of the partial large subunit rDNA gene, the rDNA internal transcribed spacer, and the partial β-tubulin. The genus most closely related to Synnemapestaloides is Seimatosporium and the species most similar to Synnemapestaloides rhododendri is Seim. foliicola which produces short synnema-like conidiomata (sporodochia. These results demonstrate that Seim. foliicola should be transferred to Synnemapestaloides, and also demonstrate that Sporocadaceae can have synnematal in addition to pycnidial and acervular conidiomata.

Topological classification and enumeration of RNA structures by genus

DEFF Research Database (Denmark)

Andersen, Joergen Ellegard; Penner, Robert C.; Reidys, Christian

2013-01-01

To an RNA pseudoknot structure is naturally associated a topological surface, which has its associated genus, and structures can thus be classified by the genus. Based on earlier work of Harer-Zagier, we compute the generating function for the number of those structures of fixed genus and minimum...

A taxonomic revision of the genus Podocarpus

NARCIS (Netherlands)

Laubenfels, de D.J.

1985-01-01

In connection with the forthcoming revision of the Coniferae for the Flora Malesiana, the author thought it necessary to revise the genus Podocarpus. Although this genus has a substantial representation in Malesia (30 species), the revision is too involved to be appropriate with the Flora Malesiana

Modular functors are determined by their genus zero data

DEFF Research Database (Denmark)

Andersen, Jørgen Ellegaard; Ueno, Kenji

2012-01-01

We prove in this paper that the genus zero data of a modular functor determines the modular functor. We do this by establishing that the S-matrix in genus one with one point labeled arbitrarily can be expressed in terms of the genus zero information and we give an explicit formula. We do not assume...

A proposed genus boundary for the prokaryotes based on genomic insights.

Science.gov (United States)

Qin, Qi-Long; Xie, Bin-Bin; Zhang, Xi-Ying; Chen, Xiu-Lan; Zhou, Bai-Cheng; Zhou, Jizhong; Oren, Aharon; Zhang, Yu-Zhong

2014-06-01

Genomic information has already been applied to prokaryotic species definition and classification. However, the contribution of the genome sequence to prokaryotic genus delimitation has been less studied. To gain insights into genus definition for the prokaryotes, we attempted to reveal the genus-level genomic differences in the current prokaryotic classification system and to delineate the boundary of a genus on the basis of genomic information. The average nucleotide sequence identity between two genomes can be used for prokaryotic species delineation, but it is not suitable for genus demarcation. We used the percentage of conserved proteins (POCP) between two strains to estimate their evolutionary and phenotypic distance. A comprehensive genomic survey indicated that the POCP can serve as a robust genomic index for establishing the genus boundary for prokaryotic groups. Basically, two species belonging to the same genus would share at least half of their proteins. In a specific lineage, the genus and family/order ranks showed slight or no overlap in terms of POCP values. A prokaryotic genus can be defined as a group of species with all pairwise POCP values higher than 50%. Integration of whole-genome data into the current taxonomy system can provide comprehensive information for prokaryotic genus definition and delimitation. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

A MONOGRAPH OF THE GENUS DIPLODISCUS* Turcz. (TILIACEAE

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A. J. G. H. KOSTERMANS

2014-01-01

Full Text Available 1. Seven species of the genus Diplodiscus are described, of which three(D. microlepis, D. parviflorus and D. decumbens are new to science, and one (D. hookerianus was formerly described as Pentace (for the description of D. decumbens cf. p. 264.2. The area of distribution of the genus covers the Malay Peninsula,Borneo and the Philippines.3. The affinities of the genus are discussed.4. A key to the species is presented.

Phylogeny and FISH probe analysis of the “Candidatus Competibacter”-lineage in wastewater treatment systems

DEFF Research Database (Denmark)

Nittami, Tadashi; McIlroy, Simon Jon; Kanai, Eri

Our understanding of the microbial ecology of enhanced biological phosphorus removal (EBPR) wastewater treatment systems has been greatly advanced through the application of molecular methods such as fluorescence in situ hybridization (FISH). Considerable attention has been directed at the identi......Our understanding of the microbial ecology of enhanced biological phosphorus removal (EBPR) wastewater treatment systems has been greatly advanced through the application of molecular methods such as fluorescence in situ hybridization (FISH). Considerable attention has been directed...... at the identification and characterization of the glycogen accumulating organisms (GAO), a phenotypic group thought to compete with the polyphosphate accumulating organisms (PAO) for resources at the theoretical expense of EBPR efficiency. Demonstrated candidates for members of the GAO phenotype include...... the gammaproteobacterial “Candidatus Competibacter”-lineage. The group is currently delineated by 8 FISH probe defined phylotypes, although further undescribed phylogenetic diversity beyond what is covered by these probes is evident. Where studied, marked differences in physiology between members are observed, including...

Review of the genus Craspedolcus Enderlein sensu lato in China, with the description of a new genus and four new species (Hymenoptera, Braconidae, Braconinae)

NARCIS (Netherlands)

Li, Y.; Achterberg, van C.; Chen, X.-x.

2017-01-01

A new genus is split off the genus Craspedolcus Enderlein, 1920 (Hymenoptera, Braconidae, Braconinae): Maculibracon gen. n. with type species Maculibracon abruptus sp. n. The genus Craspedolcus Enderlein sensu stricto is redefined, a key to both genera and to their species in China, Thailand and

Kops genus - en værkstedsrapport

DEFF Research Database (Denmark)

Gudiksen, Asgerd

2008-01-01

 Inden for Ømålsområdet optræder ordet kop både i genus femininum, masku­linum og neutrum. På Sjælland, hvor trekønssystemet er under af­vikling, kan ordet desuden være genus commune. Der kan konstateres en vis dialektgeografisk fordeling af de tre (fire) genera, men især på Sjælland er...

Current situation of "Candidatus Liberibacter asiaticus" in Guangdong, P.R. China, where citrus huanglongbing was first described

Science.gov (United States)

Citrus Huanglongbing (HLB, yellow shoot disease) was observed in Guangdong Province, Peoples’ Republic of China in the late 1800s and is endemic there, particularly in the coastal Chaoshan and Pearl River Delta plains. Since the 1990s, the center of citrus production in Guangdong has gradually shif...

Characterization of the microbial community structure in ‘Candidatus Liberibacter asiaticus’-infected citrus plants treated with antibiotics

OpenAIRE

Zhang, M.; Powell, Charles A.; Chuan, Yu; Duan, Yongping

2014-01-01

The updated PhyloChip TM G3 were used to explore the differences in the relative abundance and phylogenetic diversity of the bacterial communities associated with HLB-affected citrus plants in the field over a growing season and those treated with antibiotic combinations of AG (Ampicillin at 1000 mg/L and Gentamicin at 100 mg/L) and PS (Penicillin at 1000 mg/L and Streptomycin at 100 mg/L). Both antibiotic treatments resulted in significantly lower Las bacterial ti...

β-caryophyllene emitted from a transgenic Arabidopsis or chemical dispenser repels Diaphorina citri, vector of Candidatus Liberibacters

NARCIS (Netherlands)

Alquézar, B.; Volpe, H.X.L.; Magnani, R.F.; de Miranda, M.P.; Santos, M.A.; Wulff, N.A.; Bento, J.M.S.; Parra, J.R.P.; Bouwmeester, H.; Peña, L.

2017-01-01

Production of citrus, the main fruit tree crop worldwide, is severely threatened by Huanglongbing (HLB), for which as yet a cure is not available. Spread of this bacterial disease in America and Asia is intimately connected with dispersal and feeding of the insect vector Diaphorina citri,

β-caryophyllene emitted from a transgenic Arabidopsis or chemical dispenser repels Diaphorina citri, vector of Candidatus Liberibacters.

Science.gov (United States)

Alquézar, Berta; Volpe, Haroldo Xavier Linhares; Magnani, Rodrigo Facchini; de Miranda, Marcelo Pedreira; Santos, Mateus Almeida; Wulff, Nelson Arno; Bento, Jose Mauricio Simões; Parra, José Roberto Postali; Bouwmeester, Harro; Peña, Leandro

2017-07-17

Production of citrus, the main fruit tree crop worldwide, is severely threatened by Huanglongbing (HLB), for which as yet a cure is not available. Spread of this bacterial disease in America and Asia is intimately connected with dispersal and feeding of the insect vector Diaphorina citri, oligophagous on rutaceous host plants. Effective control of this psyllid is an important component in successful HLB management programs. Volatiles released from the non-host guava have been shown to be repellent to the psyllid and to inhibit its response to citrus odour. By analysing VOC emission from guava we identified one volatile compound, (E)-β-caryophyllene, which at certain doses exerts a repellent effect on D. citri. Non-host plant rejection mediated by (E)-β-caryophyllene is demonstrated here by using Arabidopsis over-expression and knock-out lines. For the first time, results indicate that genetically engineered Arabidopsis plants with modified emission of VOCs can alter the behaviour of D. citri. This study shows that transgenic plants with an inherent ability to release (E)-β-caryophyllene can potentially be used in new protection strategies of citrus trees against HLB.

Functional Classification of Uncultured "Candidatus Caldiarchaeum subterraneum" Using the Maple System.

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Hideto Takami

Full Text Available In this study, the metabolic and physiological potential evaluator system based on Kyoto Encyclopedia of Genes and Genomes (KEGG functional modules was employed to establish a functional classification of archaeal species and to determine the comprehensive functions (functionome of the previously uncultivated thermophile "Candidatus Caldiarchaeum subterraneum" (Ca. C. subterraneum. A phylogenetic analysis based on the concatenated sequences of proteins common among 142 archaea and 2 bacteria, and among 137 archaea and 13 unicellular eukaryotes suggested that Ca. C. subterraneum is closely related to thaumarchaeotic species. Consistent with the results of the phylogenetic analysis, clustering and principal component analyses based on the completion ratio patterns for all KEGG modules in 79 archaeal species suggested that the overall metabolic and physiological potential of Ca. C. subterraneum is similar to that of thaumarchaeotic species. However, Ca. C. subterraneum possessed almost no genes in the modules required for nitrification and the hydroxypropionate-hydroxybutyrate cycle for carbon fixation, unlike thaumarchaeotic species. However, it possessed all genes in the modules required for central carbohydrate metabolism, such as glycolysis, pyruvate oxidation, the tricarboxylic acid (TCA cycle, and the glyoxylate cycle, as well as multiple sets of sugar and branched chain amino acid ABC transporters. These metabolic and physiological features appear to support the predominantly aerobic character of Ca. C. subterraneum, which lives in a subsurface thermophilic microbial mat community with a heterotrophic lifestyle.

Germalna, a new genus for the New Caledonian cicada previously assigned to the genus Melampsalta Kolenati, plus a complement to the description of the genus Rouxalna Boulard, with the description of two new species (Insecta: Hemiptera, Cicadoidea, Cicadidae).

Science.gov (United States)

Delorme, Quentin

2018-01-31

Species previously assigned to Melampsalta Kolenati, in New Caledonia are reviewed. Morphological studies indicate that New Caledonian cicadas currently placed in this genus have been wrongly assigned and should be placed in a new genus. The genus Germalna gen. nov., is therefore erected to accommodate Germalna germaini comb. nov. The genus Germalna gen. nov. was first documented by Michel Boulard, but remained a nomen nudum until now. A redescription of the genus Rouxalna Boulard is provided and the following new species are described: Rouxalna villosa sp. nov., and Rouxalna scabens sp. nov. Male calling songs of Rouxalna rouxi Boulard and Rouxalna scabens sp. nov. are analysed and described from field recordings. A key to the species of Rouxalna is also provided.

Temperature-dependent transmission of Candidatus phytoplasma asteris by the vector leafhopper Macrosteles quadripunctulatus Kirschbaum

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F. Maggi

2014-10-01

Full Text Available A set of experiments was carried out to characterize how temperature affects the spread of chrysanthemum yellows phytoplasma (CYP, a strain of Candidatus Phytoplasma asteris, in Chrysanthemum carinatum plants transmitted by the Macrosteles quadripunctulatus leafhopper. Experiments provided data on CYP latency period in insect and plant host, M. quadripunctulatus adult mortality rate, and epidemics progression in plants under controlled conditions inside climatic chambers. Experiments were conducted at temperatures ranging between 15 and 30°C. Empirical laws for temperature-dependent epidemiological parameters were next derived and used in a dynamical model of the epidemics progression. Experiments showed that CYP epidemics was faster at higher temperatures and the model could replicate these observations with relatively high accuracy (correlation >98.03% and residuals <14.5%. The epidemics spreading rate increased linearly from 0.2 plants infected per day at 15°C to about 0.7 plants per day at 30°C, possibly due to: i faster CYP multiplication in the host plants and ii higher frequency of feeding bouts of M. quadripunctulatus at higher temperatures.

Genus I. Leptospira

Science.gov (United States)

Leptospira comprise a diverse group of bacteria. Some species cause serious infections in animals and humans. These bacteria are aerobes that consume long-chain fatty acids and alcohols as carbon and energy sources. This genus is distinguished from Leptonema or Turneriella by lack of similarity u...

Transfer of 13 species of the genus Burkholderia to the genus Caballeronia and reclassification of Burkholderia jirisanensis as Paraburkholderia jirisanensis comb. nov.

Science.gov (United States)

Dobritsa, Anatoly P; Linardopoulou, Elena V; Samadpour, Mansour

2017-10-01

A recent study of a group of Burkholderia glathei-like bacteria resulted in the description of 13 novel species of the genus Burkholderia. However, our analysis of phylogenetic positions of these species and their molecular signatures (conserved protein sequence indels) showed that they belong to the genus Caballeronia, and we propose to transfer them to this genus. The reclassified species names are proposed as Caballeroniaarationis comb. nov., Caballeroniaarvi comb. nov., Caballeroniacalidae comb. nov., Caballeroniacatudaia comb. nov., Caballeroniaconcitans comb. nov., Caballeroniafortuita comb. nov., Caballeroniaglebae comb. nov., Caballeroniahypogeia comb. nov., Caballeroniapedi comb. nov., Caballeroniaperedens comb. nov., Caballeroniaptereochthonis comb. nov., Caballeroniatemeraria comb. nov. and Caballeronia turbans comb. nov. It is also proposed to reclassify Burkholderia jirisanensis as Paraburkholderiajirisanensis comb. nov. Based on the results of the polyphasic study, B. jirisanensis had been described as a member of the A-group of the genus Burkholderiaand the most closely related to Burkholderia rhizosphaerae, Burkholderia humisilvae and Burkholderia solisilvae currently classified as belonging to the genus Paraburkholderia.

On RNA-RNA interaction structures of fixed topological genus.

Science.gov (United States)

Fu, Benjamin M M; Han, Hillary S W; Reidys, Christian M

2015-04-01

Interacting RNA complexes are studied via bicellular maps using a filtration via their topological genus. Our main result is a new bijection for RNA-RNA interaction structures and a linear time uniform sampling algorithm for RNA complexes of fixed topological genus. The bijection allows to either reduce the topological genus of a bicellular map directly, or to lose connectivity by decomposing the complex into a pair of single stranded RNA structures. Our main result is proved bijectively. It provides an explicit algorithm of how to rewire the corresponding complexes and an unambiguous decomposition grammar. Using the concept of genus induction, we construct bicellular maps of fixed topological genus g uniformly in linear time. We present various statistics on these topological RNA complexes and compare our findings with biological complexes. Furthermore we show how to construct loop-energy based complexes using our decomposition grammar. Copyright © 2015 Elsevier Inc. All rights reserved.

Higher genus correlators from the hermitian one-matrix model

International Nuclear Information System (INIS)

Ambjoern, J.; Chekhov, L.; Makeenko, Yu.

1992-01-01

We develop an iterative algorithm for the genus expansion of the hermitian NxN one-matrix model (is the Penner model in an external field). By introducing moments of the external field, we prove that the genus g contribution to the m-loop correlator depends only on 3g-2+m lower moments (3g-2 for the partition function). We present the explicit results for the partition function and the one-loop correlator in genus one. We compare the correlators for the hermitian one-matrix model with those at zero momenta for c=1 CFT and show an agreement of the one-loop correlators for genus zero. (orig.)

Phylogenomic re-assessment of the thermophilic genus Geobacillus.

Science.gov (United States)

Aliyu, Habibu; Lebre, Pedro; Blom, Jochen; Cowan, Don; De Maayer, Pieter

2016-12-01

Geobacillus is a genus of Gram-positive, aerobic, spore-forming obligate thermophiles. The descriptions and subsequent affiliations of the species in the genus have mostly been based on polyphasic taxonomy rules that include traditional sequence-based methods such as DNA-DNA hybridization and comparison of 16S rRNA gene sequences. Currently, there are fifteen validly described species within the genus. The availability of whole genome sequences has provided an opportunity to validate and/or re-assess these conventional estimates of genome relatedness. We have applied whole genome approaches to estimate the phylogenetic relatedness among the sixty-three Geobacillus strains for which genome sequences are currently publicly available, including the type strains of eleven validly described species. The phylogenomic metrics AAI (Average Amino acid Identity), ANI (Average Nucleotide Identity) and dDDH (digital DNA-DNA hybridization) indicated that the current genus Geobacillus is comprised of sixteen distinct genomospecies, including several potentially novel species. Furthermore, a phylogeny constructed on the basis of the core genes identified from the whole genome analyses indicated that the genus clusters into two monophyletic clades that clearly differ in terms of nucleotide base composition. The G+C content ranges for clade I and II were 48.8-53.1% and 42.1-44.4%, respectively. We therefore suggest that the Geobacillus species currently residing within clade II be considered as a new genus. Copyright © 2016 Elsevier GmbH. All rights reserved.

Transfer of eleven species of the genus Burkholderia to the genus Paraburkholderia and proposal of Caballeronia gen. nov. to accommodate twelve species of the genera Burkholderia and Paraburkholderia.

Science.gov (United States)

Dobritsa, Anatoly P; Samadpour, Mansour

2016-08-01

It has been proposed to split the genus Burkholderia into two genera according to phylogenetic clustering: (1) a genus retaining this name and consisting mainly of animal and plant pathogens and (2) the genus Paraburkholderia including so-called environmental bacteria. The latter genus name has been validly published recently. During the period between the effective and valid publications of the genus name Paraburkholderia, 16 novel species of the genus Burkholderiawere described, but only two of them can be classified as members of this genus based on the emended genus description. Analysis of traits and phylogenetic positions of the other 11 species shows that they belong to the genus Paraburkholderia, and we propose to transfer them to this genus. The reclassified species names are proposed as Paraburkholderia dipogonis comb. nov., Paraburkholderia ginsengiterrae comb. nov., Paraburkholderia humisilvae comb. nov., Paraburkholderia insulsa comb. nov., Paraburkholderia kirstenboschensis comb. nov., Paraburkholderia metalliresistens comb. nov., Paraburkholderia monticola comb. nov., Paraburkholderia panaciterrae comb. nov., Paraburkholderia rhizosphaerae comb. nov., Paraburkholderia solisilvae comb. nov. and Paraburkholderia susongensis comb. nov. The remaining three species are transferred to the new genus Caballeronia gen. nov. proposed to accommodate twelve species of the genera Burkholderia and Paraburkholderia forming a distinctive clade in phylogenetic trees. The new genus members are Caballeronia choica comb. nov., Caballeronia cordobensis comb. nov., Caballeronia glathei comb. nov., Caballeronia grimmiae comb. nov., Caballeronia humi comb. nov., Caballeronia megalochromosomata comb. nov., Caballeronia jiangsuensis comb. nov., Caballeronia sordidicola comb. nov., Caballeronia telluris comb. nov., Caballeronia terrestris comb. nov., Caballeronia udeis comb. nov., and Caballeronia zhejiangensis comb. nov.

The genus curve of the Abell clusters

Science.gov (United States)

Rhoads, James E.; Gott, J. Richard, III; Postman, Marc

1994-01-01

We study the topology of large-scale structure through a genus curve measurement of the recent Abell catalog redshift survey of Postman, Huchra, and Geller (1992). The structure is found to be spongelike near median density and to exhibit isolated superclusters and voids at high and low densities, respectively. The genus curve shows a slight shift toward 'meatball' topology, but remains consistent with the hypothesis of Gaussian random phase initial conditions. The amplitude of the genus curve corresponds to a power-law spectrum with index n = 0.21-0.47+0.43 on scales of 48/h Mpc or to a cold dark matter power spectrum with omega h = 0.36-0.17+0.46.

The genus curve of the Abell clusters

Science.gov (United States)

Rhoads, James E.; Gott, J. Richard, III; Postman, Marc

1994-01-01

We study the topology of large-scale structure through a genus curve measurement of the recent Abell catalog redshift survey of Postman, Huchra, and Geller (1992). The structure is found to be spongelike near median density and to exhibit isolated superclusters and voids at high and low densities, respectively. The genus curve shows a slight shift toward 'meatball' topology, but remains consistent with the hypothesis of Gaussian random phase initial conditions. The amplitude of the genus curve corresponds to a power-law spectrum with index n = 0.21(sub -0.47 sup +0.43) on scales of 48/h Mpc or to a cold dark matter power spectrum with omega h = 0.36(sub -0.17 sup +0.46).

The genus Macroditassa (Apocynaceae-Asclepiadoideae in Brazil

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Jorge Fontanella-Pereyra

2005-01-01

Full Text Available A taxonomic revision of the Brazilian species of the genus Macroditassa Malme (Apocynaceae- sclepiadoideae is presented. The genus belongs to the subfamily Asclepiadoideae R.Br. ex Burnett, tribe Asclepiadeae (R.Br. Duby, subtribe Metastelmatinae Endl. ex Meisn. and is the most closely related to the Ditassa R.Br. genus. Macroditassa has 14 taxa of which 11 are found in Brazil, where they occurr in the Atlantic forest, disturbed areas, clearings and gullies, "cerrado", "cerradão", "campo rupestre",  campos" (high-altitude savannas and sandy coast plains ("restingas". In this paper the identification key of the taxa, descriptions and illustrations, data on flowering and fruiting, as well as maps showing the geographic distribution are presented.

A Comprehensive review on the genus Plumbago with focus on ...

African Journals Online (AJOL)

Background: The genus Plumbago distributed in warm tropical regions throughout the world is the largest genus in Plumbaginaceae. Medicinal plants are characteristic to the genus Plumbago and are cultivated and utilized worldwide. Plumbago auriculata Lam. is common in South Africa and is often cultivated for its ...

A Plant Bacterial Pathogen Manipulates Its Insect Vector's Energy Metabolism

Science.gov (United States)

Hijaz, Faraj; Ebert, Timothy A.; Rogers, Michael E.

2016-01-01

ABSTRACT Insect-transmitted plant-pathogenic bacteria may alter their vectors' fitness, survival, behavior, and metabolism. Because these pathogens interact with their vectors on the cellular and organismal levels, potential changes at the biochemical level might occur. “Candidatus Liberibacter asiaticus” (CLas) is transmitted in a persistent, circulative, and propagative manner. The genome of CLas revealed the presence of an ATP translocase that mediates the uptake of ATP and other nucleotides from medium to achieve its biological processes, such as growth and multiplication. Here, we showed that the levels of ATP and many other nucleotides were significantly higher in CLas-infected than healthy psyllids. Gene expression analysis showed upregulation for ATP synthase subunits, while ATPase enzyme activity showed a decrease in ATPase activity. These results indicated that CLas stimulated Diaphorina citri to produce more ATP and many other energetic nucleotides, while it may inhibit their consumption by the insect. As a result of ATP accumulation, the adenylated energy charge (AEC) increased and the AMP/ATP and ADP/ATP ratios decreased in CLas-infected D. citri psyllids. Survival analysis confirmed a shorter life span for CLas-infected D. citri psyllids. In addition, electropenetrography showed a significant reduction in total nonprobing time, salivation time, and time from the last E2 (phloem ingestion) to the end of recording, indicating that CLas-infected psyllids were at a higher hunger level and they tended to forage more often. This increased feeding activity reflects the CLas-induced energetic stress. In conclusion, CLas alters the energy metabolism of its psyllid vector, D. citri, in order to secure its need for energetic nucleotides. IMPORTANCE Insect transmission of plant-pathogenic bacteria involves propagation and circulation of the bacteria within their vectors. The transmission process is complex and requires specific interactions at the molecular

A plastid phylogeny and character evolution of the Old World fern genus Pyrrosia (Polypodiaceae) with the description of a new genus: Hovenkampia (Polypodiaceae).

Science.gov (United States)

Zhou, Xin-Mao; Zhang, Liang; Chen, Cheng-Wei; Li, Chun-Xiang; Huang, Yao-Moan; Chen, De-Kui; Lu, Ngan Thi; Cicuzza, Daniele; Knapp, Ralf; Luong, Thien Tam; Nitta, Joel H; Gao, Xin-Fen; Zhang, Li-Bing

2017-09-01

The Old World fern genus Pyrrosia (Polypodiaceae) offers a rare system in ferns to study morphological evolution because almost all species of this genus are well studied for their morphology, anatomy, and spore features, and various hypotheses have been proposed in terms of the phylogeny and evolution in this genus. However, the molecular phylogeny of the genus lags behind. The monophyly of the genus has been uncertain and a modern phylogenetic study of the genus based on molecular data has been lacking. In the present study, DNA sequences of five plastid markers of 220 accessions of Polypodiaceae representing two species of Drymoglossum, 14 species of Platycerium, 50 species of Pyrrosia, and the only species of Saxiglossum (subfamily Platycerioideae), and 12 species of other Polypodiaceae representing the remaining four subfamilies are used to infer a phylogeny of the genus. Major results and conclusions of this study include: (1) Pyrrosia as currently circumscribed is paraphyletic in relation to Platycerium and can be divided into two genera: Pyrrosia s.s. and Hovenkampia (gen. nov.), with Hovenkampia and Platycerium forming a strongly supported clade sister to Pyrrosia s.s.; (2) Subfamily Platycerioideae should contain three genera only, Hovenkampia, Platycerium, and Pyrrosia s.s.; (3) Based on the molecular phylogeny, macromorphology, anatomical features, and spore morphology, four major clades in the genus are identified and three of the four are further resolved into four, four, and six subclades, respectively; (4) Three species, P. angustissima, P. foveolata, and P. mannii, not assigned to any groups by Hovenkamp (1986) because of their unusual morphology, each form monospecific clades; (5) Drymoglossum is not monophyletic and those species previously assigned to this genus are resolved in two different subclades; (6) Saxiglossum is resolved as the first lineage in the Niphopsis clade; and (7) The evolution of ten major morphological characters in the

Higher genus partition functions of meromorphic conformal field theories

International Nuclear Information System (INIS)

Gaberdiel, Matthias R.; Volpato, Roberto

2009-01-01

It is shown that the higher genus vacuum amplitudes of a meromorphic conformal field theory determine the affine symmetry of the theory uniquely, and we give arguments that suggest that also the representation content with respect to this affine symmetry is specified, up to automorphisms of the finite Lie algebra. We illustrate our findings with the self-dual theories at c = 16 and c = 24; in particular, we give an elementary argument that shows that the vacuum amplitudes of the E 8 x E 8 theory and the Spin(32)/Z 2 theory differ at genus g = 5. The fact that the discrepancy only arises at rather high genus is a consequence of the modular properties of higher genus amplitudes at small central charges. In fact, we show that for c ≤ 24 the genus one partition function specifies already the partition functions up to g ≤ 4 uniquely. Finally we explain how our results generalise to non-meromorphic conformal field theories.

Diterpenes from the Marine Algae of the Genus Dictyota.

Science.gov (United States)

Chen, Jiayun; Li, Hong; Zhao, Zishuo; Xia, Xue; Li, Bo; Zhang, Jinrong; Yan, Xiaojun

2018-05-11

Species of the brown algae of the genus Dictyota are rich sources of bioactive secondary metabolites with diverse structural features. Excellent progress has been made in the discovery of diterpenes possessing broad chemical defensive activities from this genus. Most of these diterpenes exhibit significant biological activities, such as antiviral, cytotoxic and chemical defensive activities. In the present review, we summarized diterpenes isolated from the brown algae of the genus.

Transfer of Pseudomonas pictorum Gray and Thornton 1928 to genus Stenotrophomonas as Stenotrophomonas pictorum comb. nov., and emended description of the genus Stenotrophomonas.

Science.gov (United States)

Ouattara, Aboubakar Sidiki; Le Mer, Jean; Joseph, Manon; Macarie, Hervé

2017-06-01

A polyphasic taxonomic approach including analysis of phenotypic, physiological and genotypic characteristics, 16S rRNA gene sequence and DNA-DNA hybridization analysis was used to determine the most consistent affiliation of Pseudomonas pictorum. Pseudomonas pictorum ATCC 23328T exhibited phenotypic traits of members of the genus Stenotrophomonas including cellular fatty acid composition, quinone and limited range of substrates that could be used. Antibiotic susceptibility and physiological characteristics were determined. The DNA G+C content was 65.7 mol%. Phylogenetic analysis revealed that the type strains of Stenotrophomonas terrae, Stenotrophomonashumi, Stenotrophomonasnitritireducens and Stenotrophomonasacidaminiphila were the nearest relatives (16S rRNA gene sequence similarity of 98.0 to 98.8 %). All the other type strains of species of the genus Stenotrophomonas showed high 16S rRNA gene sequence similarities (96.8 to 97.2 %). DNA-DNA hybridizations revealed 31.0, 32.0, 43.3 and 43.6 % reassociation between Pseudomonas pictorum ATCC 23328T and the type strains of S. terrae, S. humi, S. nitritireducens and S. acidaminiphila, respectively. Our overall results indicate that Pseudomonas pictorum should be transferred to the genus Stenotrophomonas as a novel species of this genus, Stenotrophomonas pictorum comb. nov. Since the original description of the genus Stenotrophomonaswas made with only one species (Stenotrophomonasmaltophilia), an emendation of the genus description is proposed in order to match better with the characteristics of the eleven novel species assigned to this genus since then.

What is the genus?

CERN Document Server

Popescu-Pampu, Patrick

2016-01-01

Exploring several of the evolutionary branches of the mathematical notion of genus, this book traces the idea from its prehistory in problems of integration, through algebraic curves and their associated Riemann surfaces, into algebraic surfaces, and finally into higher dimensions. Its importance in analysis, algebraic geometry, number theory and topology is emphasized through many theorems. Almost every chapter is organized around excerpts from a research paper in which a new perspective was brought on the genus or on one of the objects to which this notion applies. The author was motivated by the belief that a subject may best be understood and communicated by studying its broad lines of development, feeling the way one arrives at the definitions of its fundamental notions, and appreciating the amount of effort spent in order to explore its phenomena.

Higher-genus su(N) fusion multiplicities as polytope volumes

International Nuclear Information System (INIS)

Flynn, G; Rasmussen, J; Tahic, M; Walton, M A

2002-01-01

We show how higher-genus su(N) fusion multiplicities may be computed as the discretized volumes of certain polytopes. The method is illustrated by explicit analyses of some su(3) and su(4) fusions, but applies to all higher-point and higher-genus su(N) fusions. It is based on an extension of the realm of Berenstein-Zelevinsky triangles by including so-called gluing and loop-gluing diagrams. The identification of the loop-gluing diagrams is our main new result, since they enable us to characterize higher-genus fusions in terms of polytopes. Also, the genus-2 0-point su(3) fusion multiplicity is found to be a simple binomial coefficient in the affine level

Biodiversity of the genus Cladophialophora

Science.gov (United States)

Badali, H.; Gueidan, C.; Najafzadeh, M.J.; Bonifaz, A.; van den Ende, A.H.G. Gerrits; de Hoog, G.S.

2008-01-01

Cladophialophora is a genus of black yeast-like fungi comprising a number of clinically highly significant species in addition to environmental taxa. The genus has previously been characterized by branched chains of ellipsoidal to fusiform conidia. However, this character was shown to have evolved several times independently in the order Chaetothyriales. On the basis of a multigene phylogeny (nucLSU, nucSSU, RPB1), most of the species of Cladophialophora (including its generic type C. carrionii) belong to a monophyletic group comprising two main clades (carrionii- and bantiana-clades). The genus includes species causing chromoblastomycosis and other skin infections, as well as disseminated and cerebral infections, often in immunocompetent individuals. In the present study, multilocus phylogenetic analyses were combined to a morphological study to characterize phenetically similar Cladophialophora strains. Sequences of the ITS region, partial Translation Elongation Factor 1-α and β-Tubulin genes were analysed for a set of 48 strains. Four novel species were discovered, originating from soft drinks, alkylbenzene-polluted soil, and infected patients. Membership of the both carrionii and bantiana clades might be indicative of potential virulence to humans. PMID:19287540

The genus Baijiania (Cucurbitaceae)

NARCIS (Netherlands)

Wilde, de W.J.J.O.; Duyfjes, B.E.E.

2003-01-01

The genus Baijiania, originally thought to be indigenous in China and Borneo, appears to be restricted to Borneo. The only species is Baijiania borneensis, with two varieties, the type variety and var. paludicola Duyfjes, var. nov.

Analysis of synonymous codon usage patterns in the genus Rhizobium.

Science.gov (United States)

Wang, Xinxin; Wu, Liang; Zhou, Ping; Zhu, Shengfeng; An, Wei; Chen, Yu; Zhao, Lin

2013-11-01

The codon usage patterns of rhizobia have received increasing attention. However, little information is available regarding the conserved features of the codon usage patterns in a typical rhizobial genus. The codon usage patterns of six completely sequenced strains belonging to the genus Rhizobium were analysed as model rhizobia in the present study. The relative neutrality plot showed that selection pressure played a role in codon usage in the genus Rhizobium. Spearman's rank correlation analysis combined with correspondence analysis (COA) showed that the codon adaptation index and the effective number of codons (ENC) had strong correlation with the first axis of the COA, which indicated the important role of gene expression level and the ENC in the codon usage patterns in this genus. The relative synonymous codon usage of Cys codons had the strongest correlation with the second axis of the COA. Accordingly, the usage of Cys codons was another important factor that shaped the codon usage patterns in Rhizobium genomes and was a conserved feature of the genus. Moreover, the comparison of codon usage between highly and lowly expressed genes showed that 20 unique preferred codons were shared among Rhizobium genomes, revealing another conserved feature of the genus. This is the first report of the codon usage patterns in the genus Rhizobium.

Notes on the genus Digitaria, with descriptions of new species

NARCIS (Netherlands)

Henrard, J.Th.

1934-01-01

Some years ago I had the opportunity to study more extensively a very interesting group of grasses, belonging to what is now accepted as a distinct genus, the genus Digitaria, formerly belonging as a subgenus to the genus Panicum. As to living plants of this group I was familiar with two european

An investigation of self-incompatibility within the genus Restrepia.

Science.gov (United States)

Millner, Helen J; McCrea, Alison R; Baldwin, Timothy C

2015-03-01

• The genus Restrepia (Orchidaceae) is indigenous to montane rain forests of Central and South America. Recently, as habitat has fragmented and wild populations dwindled, the chances for successful cross-pollination within the genus have been reduced. Since cultivated species of Restrepia have been vegetatively propagated, they remain genetically close to those in the wild, making ex situ collections of the genus useful model populations for investigating breeding systems. Restrepia are found in clade B of the Pleurothallidinae, the only clade in which self-incompatibility (SI) has not yet been confirmed. In the current study, private collections of Restrepia were used to study the operation of SI within the genus to assist future ex situ conservation of this and related genera.• A variety of self-pollination, intraspecific, and interspecific crosses were performed across the genus, and pollen tube growth was studied.• Individual species exhibited varying degrees of SI. Self-pollinations performed across 26 species in the genus produced few viable seeds, with the exception of R. aberrans. Viable "filled" seeds with embryos were shown to require an intraspecific cross. Primary hybrids between species produced >90% seeds with embryos that germinated well.• The type of SI operating within the genus was considered to be best explained by gametophytic self-incompatibility (GSI) with interspecific variation in its phenotypic expression. The implications of these findings are discussed in relation to SI in the Pleurothallidinae and conservation strategies for Restrepia and related genera. © 2015 Botanical Society of America, Inc.

Quantum field theory on higher-genus Riemann surfaces

International Nuclear Information System (INIS)

Kubo, Reijiro; Yoshii, Hisahiro; Ojima, Shuichi; Paul, S.K.

1989-07-01

Quantum field theory for b-c systems is formulated on Riemann surfaces with arbitrary genus. We make use of the formalism recently developed by Krichever and Novikov. Hamiltonian is defined properly, and the Ward-Takahashi identities are derived on higher-genus Riemann surfaces. (author)

Molecular phylogeny and taxonomy of the genus Veloporphyrellus

Science.gov (United States)

Yan-Chun Li; Beatriz Ortiz-Santana; Nian-Kai Zeng; Bang Feng; Zhu L. Yang

2014-01-01

Veloporphyrellus is a genus known from North and Central America, southeastern Asia, and Africa. Because species of this genus are phenotypically similar to some taxa in several genera, such as Boletellus, Leccinum, Strobilomyces, Suillus and Tylopilus s.l. belonging to Boletales, its phylogenetic disposition has...

Diversity of secondary metabolites from Genus Artocarpus (Moraceae

Directory of Open Access Journals (Sweden)

ALIEFMAN HAKIM

2010-11-01

Full Text Available Hakim A. 2010. The diversity of secondary metabolites from Genus Artocarpus (Moraceae. Nusantara Bioscience 2:146-156. Several species of the Artocarpus genus (Moraceae have been investigated their natural product. The secondary metabolites successfully being isolatad from Artocarpus genus consist of terpenoid, flavonoids, stilbenoid, arylbenzofuran, neolignan, and adduct Diels-Alder. Flavonoid group represent the compound which is the most found from Artocarpus plant. The flavonoids compound which are successfully isolated from Artocarpus plant consist of the varied frameworks like chalcone, flavanone, flavan-3-ol, simple flavone, prenylflavone, oxepinoflavone, pyranoflavone, dihydrobenzoxanthone, furanodihydrobenzoxanthone, pyranodihydrobenzoxanthone, quinonoxanthone, cyclopentenoxanthone, xanthonolide, dihydroxanthone.

Genus delineation of Chlamydiales by analysis of the percentage of conserved proteins justifies the reunifying of the genera Chlamydia and Chlamydophila into one single genus Chlamydia

NARCIS (Netherlands)

Pannekoek, Yvonne; Qi-Long, Qin; Zhang, Yu-Zhong; van der Ende, Arie

2016-01-01

Many studies have aimed to set up boundaries for the classification and definition of prokaryotic genus and species classification; however, studies that focused on genus-level genomic differences for existing taxonomy systems are limited. Recently, a novel method was described for prokaryotic genus

Phytochemical and Ethno-Pharmacological Review of the Genus ...

African Journals Online (AJOL)

Distribution, traditional uses, isolated chemical constituents and pharmacological activities of some common species of the genus Araucaria are reviewed in this paper. Almost 19 species belong to the genus, Araucaria. It is indigenous to North. America. Biflavanoid, diterpene, phenyl propanoid and lignans are abundant in ...

Identification and nomenclature of the genus Penicillium.

Science.gov (United States)

Visagie, C M; Houbraken, J; Frisvad, J C; Hong, S-B; Klaassen, C H W; Perrone, G; Seifert, K A; Varga, J; Yaguchi, T; Samson, R A

2014-06-01

Penicillium is a diverse genus occurring worldwide and its species play important roles as decomposers of organic materials and cause destructive rots in the food industry where they produce a wide range of mycotoxins. Other species are considered enzyme factories or are common indoor air allergens. Although DNA sequences are essential for robust identification of Penicillium species, there is currently no comprehensive, verified reference database for the genus. To coincide with the move to one fungus one name in the International Code of Nomenclature for algae, fungi and plants, the generic concept of Penicillium was re-defined to accommodate species from other genera, such as Chromocleista, Eladia, Eupenicillium, Torulomyces and Thysanophora, which together comprise a large monophyletic clade. As a result of this, and the many new species described in recent years, it was necessary to update the list of accepted species in Penicillium. The genus currently contains 354 accepted species, including new combinations for Aspergillus crystallinus, A. malodoratus and A. paradoxus, which belong to Penicillium section Paradoxa. To add to the taxonomic value of the list, we also provide information on each accepted species MycoBank number, living ex-type strains and provide GenBank accession numbers to ITS, β-tubulin, calmodulin and RPB2 sequences, thereby supplying a verified set of sequences for each species of the genus. In addition to the nomenclatural list, we recommend a standard working method for species descriptions and identifications to be adopted by laboratories working on this genus.

Spiky higher genus strings

International Nuclear Information System (INIS)

Ambjoern, J.; Bellini, A.; Johnston, D.

1990-10-01

It is clear from both the non-perturbative and perturbative approaches to two-dimensional quantum gravity that a new strong coupling regime is setting in at d=1, independent of the genus of the worldsheet being considered. It has been suggested that a Kosterlitz-Thouless (KT) phase transition in the Liouville theory is the cause of this behaviour. However, it has recently been pointed out that the XY model, which displays a KT transition on the plane and the sphere, is always in the strong coupling, disordered phase on a surface of constant negative curvature. A higher genus worldsheet can be represented as a fundamental region on just such a surface, which might seem to suggest that the KT picture predicts a strong coupling region for arbitrary d, contradicting the known results. We resolve the apparent paradox. (orig.)

A taxonomic revision of the Genus Origanum (Labiatae)

NARCIS (Netherlands)

Ietswaart, J.H.

1980-01-01

The present study deals with the systematics and taxonomy of the genus Origanum (Labiatae, Saturejeae). As this difficult genus was never before monographed, a revisional study was much needed. The data presented are mainly based on the study of herbarium specimens and in some cases of living ones.

The genus Gloriosa (Colchicaceae) : ethnobotany, phylogeny and taxonomy

NARCIS (Netherlands)

Maroyi, A.

2012-01-01

This thesis focuses on the ethnobotany, phylogeny and taxonomy of the genus Gloriosa L. over its distributional range. Some Gloriosa species are known to have economic and commercial value, but the genus is also well known for its complex alpha taxonomy. An appropriate taxonomy for this group is of

Characterization of the denitrification-associated phosphorus uptake properties of "Candidatus Accumulibacter phosphatis" clades in sludge subjected to enhanced biological phosphorus removal.

Science.gov (United States)

Kim, Jeong Myeong; Lee, Hyo Jung; Lee, Dae Sung; Jeon, Che Ok

2013-03-01

To characterize the denitrifying phosphorus (P) uptake properties of "Candidatus Accumulibacter phosphatis," a sequencing batch reactor (SBR) was operated with acetate. The SBR operation was gradually acclimated from anaerobic-oxic (AO) to anaerobic-anoxic-oxic (A2O) conditions by stepwise increases of nitrate concentration and the anoxic time. The communities of "Ca. Accumulibacter" and associated bacteria at the initial (AO) and final (A2O) stages were compared using 16S rRNA and polyphosphate kinase genes and using fluorescence in situ hybridization (FISH). The acclimation process led to a clear shift in the relative abundances of recognized "Ca. Accumulibacter" subpopulations from clades IIA > IA > IIF to clades IIC > IA > IIF, as well as to increases in the abundance of other associated bacteria (Dechloromonas [from 1.2% to 19.2%] and "Candidatus Competibacter phosphatis" [from 16.4% to 20.0%]), while the overall "Ca. Accumulibacter" abundance decreased (from 55.1% to 29.2%). A series of batch experiments combined with FISH/microautoradiography (MAR) analyses was performed to characterize the denitrifying P uptake properties of the "Ca. Accumulibacter" clades. In FISH/MAR experiments using slightly diluted sludge (∼0.5 g/liter), all "Ca. Accumulibacter" clades successfully took up phosphorus in the presence of nitrate. However, the "Ca. Accumulibacter" clades showed no P uptake in the presence of nitrate when the sludge was highly diluted (∼0.005 g/liter); under these conditions, reduction of nitrate to nitrite did not occur, whereas P uptake by "Ca. Accumulibacter" clades occurred when nitrite was added. These results suggest that the "Ca. Accumulibacter" cells lack nitrate reduction capabilities and that P uptake by "Ca. Accumulibacter" is dependent upon nitrite generated by associated nitrate-reducing bacteria such as Dechloromonas and "Ca. Competibacter."

Revision of the Late Permian Non-Marine Bivalve Genus Verneuilunio Starobogatov, 1987

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M.N. Urazaeva

2015-03-01

Full Text Available The genus Verneuilunio (type species Naiadites verneuili has been singled out from the genus Palaeanodonta Amalitzky based on differences in the structure of hinge margin established using the literature data. Both genera have been included in the family Palaeanodontidae, which used to be considered by the discoverer of this genus as a subjective synonym for the family Palaeomutelidae. The revision of W. Amalitskii’s collection has demonstrated that the original diagnosis of the genus con-tains a number of inaccuracies. This creates difficulties for identification of the genus Verneuilunio and complicates its placement within higher taxa. The paper presents a revised diagnosis of the genus Verneuilunio. The detailed description of its type species is provided. The genus Verneuilunio has been assigned to the family Naiaditidae based on the duplivincular and slightly amphidetic ligament. According to this feature, the genus under study is significantly different from other unio-like Late Permian non-marine bivalve genera (Palaeomutela, Palaeanodonta, Oligodontella, and Opokiella, often occurring in the same strata. The genus Verneuilunio mostly resembles some Late Carboniferous “atypical” unio-like species of the genus Anthraconaia Trueman et Weir. Statistical processing of the biometric parameters of Verneuilunio verneuili and the species A. pruvosti, mostly resembling it, has revealed statistically significant differences in elongation of the posterior end of the shell. To date, the geographic range of the genus Verneuilunio is restricted to the central part of the East European Platform, whereas its stratigraphic range is in the lower sublayer of the Severodvinsk layer.

Khmeriosicyos, a new monotypic genus of Cucurbitaceae from Cambodia

NARCIS (Netherlands)

Wilde, de W.J.J.O.; Duyfjes, B.E.E.; Ham, van der R.W.J.M.

2004-01-01

A new monotypic genus from Cambodia is described. The genus is defined by a unique combination of characters and has distinct pollen features. The only species is Khmeriosicyos harmandii W.J. de Wilde & Duyfjes.

Anticancer Activity Of Plant Genus Clerodendrum (Lamiaceae: A Review

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Donald Emilio Kalonio

2017-12-01

Full Text Available Plants of the genus Clerodendrum (Lamiaceae is widespread in tropical and subtropical regions. Plants of this genus are used both empirically and scientifically as anti-inflammatory, antidiabetic, antimalarial, antiviral, antihypertensive, hypolipidemic, antioxidant, and antitumor. Results of the molecular docking simulation of chemical content of these plants could potentially provide an anticancer effect. This paper aims to review the anticancer activity of plant genus Clerodendrum based on scientific data. The method used in this study is the literature study. Searches were conducted online (in the database PubMed, Science Direct and Google Scholar and on various books (Farmakope Herbal Indonesia and PROSEA. A total 12 plants of the genus Clerodendrum have anticancer activity in vitro and in vivo, thus potentially to be developed as a source of new active compounds with anticancer activity.

Revision of the genus Trypeticus Marseul (Coleoptera: Histeridae)

NARCIS (Netherlands)

Kanaar, P.

2003-01-01

The genus Trypeticus Marseul, 1864 is revised and figured. A key to the species is given. Redescriptions of the hitherto described species are presented. The number of species in this genus has been brought up to 100, of which 72 species are described as new: T. adebratti (Sabah, Brunei), T.

Genus delineation of Chlamydiales by analysis of the percentage of conserved proteins justifies the reunifying of the genera Chlamydia and Chlamydophila into one single genus Chlamydia.

Science.gov (United States)

Pannekoek, Yvonne; Qi-Long, Qin; Zhang, Yu-Zhong; van der Ende, Arie

2016-08-01

Many studies have aimed to set up boundaries for the classification and definition of prokaryotic genus and species classification; however, studies that focused on genus-level genomic differences for existing taxonomy systems are limited. Recently, a novel method was described for prokaryotic genus delineation using the percentage of conserved proteins (POCP) between two strains to estimate their evolutionary and phenotypic distance (Qin et al. A proposed genus boundary for the prokaryotes based on genomic insights. J Bacteriol 2014; 196: :2210-5). Here, we extended the POCP analysis of the order Chlamydiales and pairwise compared all currently recognized species and candidate species of the family Chlamydiaceae as well as some species from other families. Using the taxonomy advised by the International Committee on Systematics of Prokaryotes, subcommittee on the taxonomy of the Chlamydiae, POCP analysis revealed that all pairwise comparisons of species from different families resulted in values lower than 50%, the proposed threshold for genus boundary. In contrast, all interspecies pairwise comparisons of species from the single genus within the family Chlamydiaceae resulted in POCP values higher than 70%. We conclude that the recommended genus classification of the family Chlamydiaceae is rational and that POCP analyses can provide a robust genomic index for the taxonomy of members of the order Chlamydiales in terms of genus demarcation. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

On genus expansion of superpolynomials

Energy Technology Data Exchange (ETDEWEB)

Mironov, Andrei, E-mail: mironov@itep.ru [Lebedev Physics Institute, Moscow 119991 (Russian Federation); ITEP, Moscow 117218 (Russian Federation); National Research Nuclear University MEPhI, Moscow 115409 (Russian Federation); Morozov, Alexei, E-mail: morozov@itep.ru [ITEP, Moscow 117218 (Russian Federation); National Research Nuclear University MEPhI, Moscow 115409 (Russian Federation); Sleptsov, Alexei, E-mail: sleptsov@itep.ru [ITEP, Moscow 117218 (Russian Federation); Laboratory of Quantum Topology, Chelyabinsk State University, Chelyabinsk 454001 (Russian Federation); KdVI, University of Amsterdam (Netherlands); Smirnov, Andrey, E-mail: asmirnov@math.columbia.edu [ITEP, Moscow 117218 (Russian Federation); Columbia University, Department of Mathematics, New York (United States)

2014-12-15

Recently it was shown that the (Ooguri–Vafa) generating function of HOMFLY polynomials is the Hurwitz partition function, i.e. that the dependence of the HOMFLY polynomials on representation R is naturally captured by symmetric group characters (cut-and-join eigenvalues). The genus expansion and expansion through Vassiliev invariants explicitly demonstrate this phenomenon. In the present paper we claim that the superpolynomials are not functions of such a type: symmetric group characters do not provide an adequate linear basis for their expansions. Deformation to superpolynomials is, however, straightforward in the multiplicative basis: the Casimir operators are β-deformed to Hamiltonians of the Calogero–Moser–Sutherland system. Applying this trick to the genus and Vassiliev expansions, we observe that the deformation is fully straightforward only for the thin knots. Beyond the family of thin knots additional algebraically independent terms appear in the Vassiliev and genus expansions. This can suggest that the superpolynomials do in fact contain more information about knots than the colored HOMFLY and Kauffman polynomials. However, even for the thin knots the beta-deformation is non-innocent: already in the simplest examples it seems inconsistent with the positivity of colored superpolynomials in non-(anti)symmetric representations, which also happens in I. Cherednik's (DAHA-based) approach to the torus knots.

BRST quantization of superconformal theories on higher genus Riemann surfaces

International Nuclear Information System (INIS)

Leman Kuang

1992-01-01

A complex contour integral method is constructed and applied to the Becchi-Rouet-Stora-Tyutin (BRST) quantization procedure of string theories on higher genus Riemann surfaces with N=0 and 1 Krichever-Novikov (KN) algebras. This method makes calculations very simple. It is shown that the critical spacetime dimension of the string theories on a genus-g Riemann surface equals that of the string theories on a genus-zero Riemann surface, and that the 'Regge intercepts' in the genus-g case are α(g)=1-3/4g-9/8g 2 and 1/2-3/4g-17/16g 2 for bosonic strings and superstrings, respectively. (orig.)

The ascomycete genus Sordaria

OpenAIRE

Guarro, J.; Arx, von, J.A.

1987-01-01

Sordaria is restricted to coprophilous, soil-, or seed-borne Pyrenomycetes with aseptate, elongate ascospores with a gelatinous, amorphous sheath. The genus is redescribed and a key to fourteen accepted species is given. A checklist of all taxa described as Sordaria is added.

A preliminary survey of the genus Buchwaldoboletus (Boletales: Boletaceae)

Science.gov (United States)

Beatriz Ortiz-Santana; Ernst E. Both

2011-01-01

Buchwaldoboletus is a small genus of about a dozen species with a world-wide distribution. The boletes of this genus are non-mycorrhizal, saprophytic and lignicolous. A preliminary survey is provided and seven new combinations are proposed.

Identification and nomenclature of the genus Penicillium

DEFF Research Database (Denmark)

Visagie, C.M.; Houbraken, J.; Frisvad, Jens Christian

2014-01-01

Penicillium is a diverse genus occurring worldwide and its species play important roles as decomposers of organic materials and cause destructive rots in the food industry where they produce a wide range of mycotoxins. Other species are considered enzyme factories or are common indoor air allergens....... Although DNA sequences are essential for robust identification of Penicillium species, there is currently no comprehensive, verified reference database for the genus. To coincide with the move to one fungus one name in the International Code of Nomenclature for algae, fungi and plants, the generic concept...... of accepted species in Penicillium. The genus currently contains 354 accepted species, including new combinations for Aspergillus crystallinus, A. malodoratus and A. paradoxus, which belong to Penicillium section Paradoxa. To add to the taxonomic value of the list, we also provide information on each accepted...

The chemistry and pharmacology of Cleome genus: A review.

Science.gov (United States)

Singh, Harpreet; Mishra, Amrita; Mishra, Arun Kumar

2018-05-01

Since ancient times, species of Cleome genus are used to cure various ailments in human beings and same is stated in traditional treatises. Each part of the plant has its own significance, therefore, in background of its significance, upto date information in systematic manner is required. The present review embarks on variety of naturally occurring compounds that have been isolated from various species of Cleome genus. The present study furnishes an overview of all naturally isolated compounds diterpenes, triterpenoids, trinorterpenoids, flavonol glycoside, coumarinolignoids, dipyridodiazepinone, essential oils, sesquiterpenes, flavonoids, carboxylic acid derivatives, lactone derivatives, sterols and pharmacological activities of various species of Cleome genus. These plants of Cleome genus are often used as conventional drugs to treat several ailments therefore information on analgesic, anti-inflammatory, antifungal, antimicrobial, anti-diarrheal, anticancer, anti-arthritic, hepatoprotective, antinociceptive, wound healing and psychopharmacological activity etc were compiled. Literature regarding the compounds isolated and pharmacological studies performed by various researchers in the last 40 years who worked on different species belonging to genus Cleome was summarized in the present review. On the basis of references, this review covers the phytochemistry and pharmacology of Cleome species, describing compounds previously reported current trends and future prospects. From a wellbeing point of view, species belonging toCleome genus presents an excellent option for curing variety of ailments in human beings due to its isolated phytocompounds that reveal significant biological activities or for developing a variety of new pharmaceutical products. The observed pharmacological activities and no toxicity profile of extracts obtained from species of Cleome genus support the statement that these extracts might be used in the formation of new formulations that can be

Revisiting the genus Photobacterium: taxonomy, ecology and pathogenesis.

Science.gov (United States)

Labella, Alejandro M; Arahal, David R; Castro, Dolores; Lemos, Manuel L; Borrego, Juan J

2017-03-01

The genus Photobacterium, one of the eight genera included in the family Vibrionaceae, contains 27 species with valid names and it has received attention because of the bioluminescence and pathogenesis mechanisms that some of its species exhibit. However, the taxonomy and phylogeny of this genus are not completely elucidated; for example, P. logei and P. fischeri are now considered members of the genus Aliivibrio, and previously were included in the genus Vibrio. In addition, P. damselae subsp. piscicida was formed as a new combination for former Vibrio damsela and Pasteurella piscicida. Moreover, P. damselae subsp. damselae is an earlier heterotypic synonym of P. histaminum. To avoid these incovenences draft and complete genomic sequences of members of Photobacterium are increasingly becoming available and their use is now routine for many research laboratories to address diverse goals: species delineation with overall genomic indexes, phylogenetic analyses, comparative genomics, and phenotypic inference. The habitats and isolation source of the Photobacterium species include seawater, sea sediments, saline lake waters, and a variety of marine organisms with which the photobacteria establish different relationships, from symbiosis to pathogenic interactions. Several species of this genus contain bioluminescent strains in symbiosis with marine fish and cephalopods; in addition, other species enhance its growth at pressures above 1 atmosphere, by means of several high-pressure adaptation mechanisms and for this, they may be considered as piezophilic (former barophilic) bacteria. Until now, only P. jeanii, P. rosenbergii, P. sanctipauli, and the two subspecies of P. damselae have been reported as responsible agents of several pathologies on animal hosts, such as corals, sponges, fish and homeothermic animals. In this review we have revised and updated the taxonomy, ecology and pathogenicity of several members of this genus. [Int Microbiol 20(1): 1-10 (2017

Non-abelian bosonization in higher genus Riemann surfaces

International Nuclear Information System (INIS)

Koh, I.G.; Yu, M.

1988-01-01

We propose a generalization of the character formulas of the SU(2) Kac-Moody algebra to higher genus Riemann surfaces. With this construction, we show that the modular invariant partition funciton of the SO(4) k = 1 Wess-Zumino model is equivalent, in arbitrary genus Riemann surfaces, to that of free fermion theory. (orig.)

Genus two finite gap solutions to the vector nonlinear Schroedinger equation

International Nuclear Information System (INIS)

Woodcock, Thomas; Warren, Oliver H; Elgin, John N

2007-01-01

A recently published article presents a technique used to derive explicit formulae for odd genus solutions to the vector nonlinear Schroedinger equation. In another article solutions of genus two are derived using a different approach which assumes a separable ansatz. In this communication, the extension of the first technique to the even genus case is discussed, and this extension is carried out explicitly for genus two. Furthermore, a birational mapping is found between the spectral curves that arise in the two approaches. (fast track communication)

Higher genus correlators for the complex matrix model

International Nuclear Information System (INIS)

Ambjorn, J.; Kristhansen, C.F.; Makeenko, Y.M.

1992-01-01

In this paper, the authors describe an iterative scheme which allows us to calculate any multi-loop correlator for the complex matrix model to any genus using only the first in the chain of loop equations. The method works for a completely general potential and the results contain no explicit reference to the couplings. The genus g contribution to the m-loop correlator depends on a finite number of parameters, namely at most 4g - 2 + m. The authors find the generating functional explicitly up to genus three. The authors show as well that the model is equivalent to an external field problem for the complex matrix model with a logarithmic potential

PHYSICS OF NON-GAUSSIAN FIELDS AND THE COSMOLOGICAL GENUS STATISTIC

International Nuclear Information System (INIS)

James, J. Berian

2012-01-01

We report a technique to calculate the impact of distinct physical processes inducing non-Gaussianity on the cosmological density field. A natural decomposition of the cosmic genus statistic into an orthogonal polynomial sequence allows complete expression of the scale-dependent evolution of the topology of large-scale structure, in which effects including galaxy bias, nonlinear gravitational evolution, and primordial non-Gaussianity may be delineated. The relationship of this decomposition to previous methods for analyzing the genus statistic is briefly considered and the following applications are made: (1) the expression of certain systematics affecting topological measurements, (2) the quantification of broad deformations from Gaussianity that appear in the genus statistic as measured in the Horizon Run simulation, and (3) the study of the evolution of the genus curve for simulations with primordial non-Gaussianity. These advances improve the treatment of flux-limited galaxy catalogs for use with this measurement and further the use of the genus statistic as a tool for exploring non-Gaussianity.

Femeniasia, novus genus Carduearum

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Susanna de la Serna, Alfonso

1988-01-01

Full Text Available The systematic position of Centaurea balearica Rodríguez Femenias (Asteraceae-Cardueae is studied. A detailed analysis or its anatomy, with special reference to the carpology, forces the author lo reject its inclusion in the genus Centaurea or in any other genus or the tribe. A new genus, Femeniasia Susanna. is hence described, and the new nomenclatural combinari en Femeniasia balearica (Rodríguez Femenías Susanna is proposed. The relationship or Femeniasia and the other genera of the tribe is discussed; the author concludes that Femeniasia is a quite isolated genus in the Cardueae-Carduinae .

[ca] Estudi de la posició sistemàtica de Centaurea balearica Rodríguez Femenías (Asteraceae-Cardueae . De l'anàlisi minuciosa de la seva anatomia, especialment de les seves cípseles, resulta que l'esmentada espècie no és cap Centaurea; tampoc pot ésser inclosa en cap del altres gèneres de la tribu. En conseqüència, hom descriu un nou gènere, Femeniasia Susanna, i proposa la combinació Femeniasia balearica (Rodríguez Femenías Susanna. Son analitzades les possibles relacions de parentiu amb d'altres gèneres del grup i l'autor arriba a la conclusió que Femeniasia és un gènere clarament isolat entre les Cardueae-Carduinae.

The genus Artemisia: a comprehensive review.

Science.gov (United States)

Bora, Kundan Singh; Sharma, Anupam

2011-01-01

Medicinal plants are nature's gift to human beings to make disease free healthy life, and play a vital role to preserve our health. They are believed to be much safer and proven elixir in the treatment of various ailments. The genus Artemisia (Astraceae) consists of about 500 species, occurring throughout the world. The present review comprises the ethnopharmacological, phytochemical and therapeutic potential of various species of Artemisia. The aim of this this review is to bring together most of the available scientific research conducted on the genus Artemisia, which is currently scattered across various publications. Through this review the authors hope to attract the attention of natural product researchers throughout the world to focus on the unexplored potential of Artemisia species. This review has been compiled using references from major databases such as Chemical Abstracts, Medicinal and Aromatic Plants Abstracts, ScienceDirect, SciFinder, PubMed, King's American Dispensatory, Henriette's Herbal Homepage, Dr. Duke's Phytochemical and Ethnobotanical Databases. An exhaustive survey of literature revealed that the different species of Artemisia have a vast range of biological activities including antimalarial, cytotoxic, antihepatotoxic, antibacterial, antifungal and antioxidant activity. Some very important drug leads have been discovered from this genus, notably artemisinin, the well known antimalarial drug isolated from the Chinese herb Artemisia annua. Terpenoids, flavonoids, coumarins, caffeoylquinic acids, sterols and acetylenes constitute major classes of phytoconstituents of the genus. Various species of Artemisia seems to hold great potential for in-depth investigation for various biological activities, especially their effects on the central nervous and cardiovascular systems.

The neotropical genus Opeatocerata Melander (Díptera, Empididae

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Kenneth G. V. Smith

1989-01-01

Full Text Available The Neotropical empidid genus Opeatocerata Melander, hitherto known from only a sigle female from Mexico, is redefined in the light of new material, including males. Three new species are described and illustrated, a key provided and the presence of the genus now additionally established in Costa Rica, Panama, Bolivia, Ecuador, Trinidad and Brazil.

Hayata glandulifera (Orchidaceae, New Genus and Species From Northern Vietnam

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Leonid V. Averyanov

2009-11-01

Full Text Available New orchid related to Cheirostylis, Goodyera, Rhomboda and Zeuxine discovered in lowland central part of northern Vietnam is described in rank of separate genus Hayata. Proposed genus differs from Goodyera in 2 separate lateral stigmas; in not hairy hypochile; in massive, knob-like mesochile and in large 2-lobed, dentate epichile. It differs from Cheirostylis in large flowers with completely free sepals (newer forming tube; in peculiar bunches of capitate glands on lateral walls of hypochile and in not swollen succulent rhizome forming normal adventitious roots, not modified into ridges or pillows covered by root hairs. From Rhomboda discovered genus differs in absence of any keels on the lip; in specific papillae bunches inside hypochile and in not winged column. New genus may be also close to Zeuxine, from which it differs in plant habit, large flowers, large dentate lobes of epichile and in specific shape of stelidia and rostellar arms. Described plant not fits well with any genera of subtribe Goodyerinae and certainly desires generic segregation. Besides Vietnamese plant, described genus includes H. tabiyahanensis from Taiwan and H. sherriffii from Bhutan. Standard taxonomical treatment of new genus and key for its species identification is presented in the paper.

Review of the genus Craspedolcus Enderlein sensu lato in China, with the description of a new genus and four new species (Hymenoptera, Braconidae, Braconinae).

Science.gov (United States)

Li, Yang; van Achterberg, Cornelis; Chen, Xue-Xin

2017-01-01

A new genus is split off the genus Craspedolcus Enderlein, 1920 (Hymenoptera, Braconidae, Braconinae): Maculibracon gen. n. with type species Maculibracon abruptus sp. n. The genus Craspedolcus Enderlein sensu stricto is redefined, a key to both genera and to their species in China, Thailand and Vietnam is included. Craspedolcus obscuriventris Enderlein, 1920, ( syn. n. ) is a new synonym of Craspedolcus vagatus (Smith, 1858), as Ipobracon maculicosta Enderlein, 1920 and Iphiaulax bhotanensis Cameron, 1907 of Maculibracon simlaensis (Cameron, 1899), comb. n . The genus Craspedolcus is recorded from China for the first time with two species: Craspedolcus fraternus Enderlein, 1920, and Craspedolcus politus sp. n. The genus Maculibracon is represented by three species in China: Maculibracon simlaensis (Cameron, 1899), comb. n. (also present in Vietnam), Maculibracon hei sp. n. and Maculibracon luteonervis sp. n. and a fourth species is described from Thailand: Maculibracon abruptus sp. n. Hybogaster zebripterae Wang & Chen, 2008, from China (Fujian) is transferred to Iphiaulax Foerster, 1863, ( comb. n. ) and the following names are new combinations in Maculibracon gen. n. : Bracon lepcha Cameron, 1899; Bracon phaedo Cameron, 1899; Bracon simlaensis Cameron, 1899; Iphiaulax bhotanensis Cameron, 1907; Iphiaulax laertius Cameron, 1903; Iphiaulax leptopterus Cameron, 1903; Iphiaulax lineaticarinatus Cameron, 1907; Ipobracon lissotomus Roman, 1914; Ipobracon maculicosta Enderlein, 1920 and Iphiaulax pallidicornis Roman, 1914. Craspedolcus montezuma (Cameron, 1887) is provisionally transferred to the genus Digonogastra Viereck, 1912.

Therapeutic value of the genus Alpinia, Zingiberaceae

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Cristiane P. Victório

2011-02-01

Full Text Available Plants containing bioactive substances have increasingly become the object of research studies, particularly those plants with therapeutic value. Many species of the genus Alpinia provide a variety of medicinal properties, such as, Alpinia zerumbet (Pers. Burtt et Smith and A. purpurata (Vieill K. Schum, which have a significant presence in Brazil. These species have been commercialized in the food and cosmetic industries. However, their greatest importance arises from the medicinal properties of their essential oils containing flavonoids, terpenoids and kavalactones which have been used in folk medicine to treat, for example, arterial hypertension and inflammatory processes. In addition, such species are also used in multidisciplinary studies, including phytochemistry, ethnobotany and biology, indicating the key pharmacological role of this genus in everyday life. Therefore, this work aims to present a bibliographic review of the genus Alpinia and its significance in therapeutic applications.

Comparative Genomics Reveals High Genomic Diversity in the Genus Photobacterium

OpenAIRE

Henrique Machado; Henrique Machado; Lone Gram

2017-01-01

Vibrionaceae is a large marine bacterial family, which can constitute up to 50% of the prokaryotic population in marine waters. Photobacterium is the second largest genus in the family and we used comparative genomics on 35 strains representing 16 of the 28 species described so far, to understand the genomic diversity present in the Photobacterium genus. Such understanding is important for ecophysiology studies of the genus. We used whole genome sequences to evaluate phylogenetic relationship...

Palynology of the Genus Stachytarpheta Vahl. (Verbenaceae

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Olubukola ADEDEJI

2010-12-01

Full Text Available The exine morphology of pollen grains of Stachytarpheta indica (Linn. Vahl, Stachytarpheta cayennensis (Rich. Vahl and Stachytarpheta angustifolia (Mill. Vahl is reported. This study was carried out with a light microscope. Pollen grains from fresh anthers were collected and aceolysed. Statistical analysis used to analyse the data collected include cluster analysis, correlation analysis, similarity and distance indices. The pollen grains are spheroidal to oblate to sub-oblate in shape. They are aperturate, both colpate and porate. Tricolpate types occur most frequently, acolpate, monocolpate, bicolpate and tetracolpate types less frequently. The multicolpate and multiporate attributes in all the species indicate that the genus is not primitive in evolutionary history and this species probably, evolved around in the same time. According to the size, the pollen grains of the genus falls into groups permagna (pollen diameter 100-200 ?m and giganta (pollen diameter greater than 200 ?m. S. cayennensis and S. anguistifolia belong to group permagna and S. indica only in the group giganta. This separates S. indica from the other two species. The large pollen grain size in the genus clearly supports the fact that the flowers in the genus are more insect-and-bird pollinated than wind pollinated. The similarity and distance indices of the species showed that S. cayennensis and S. angustifolia are the closest. S. indica is closer to S. angustifolia but farther from S. cayennensis.

Phylogeny of the plant genus Pachypodium (Apocynaceae

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Dylan O. Burge

2013-04-01

Full Text Available Background. The genus Pachypodium contains 21 species of succulent, generally spinescent shrubs and trees found in southern Africa and Madagascar. Pachypodium has diversified mostly into arid and semi-arid habitats of Madagascar, and has been cited as an example of a plant group that links the highly diverse arid-adapted floras of Africa and Madagascar. However, a lack of knowledge about phylogenetic relationships within the genus has prevented testing of this and other hypotheses about the group.Methodology/Principal Findings. We use DNA sequence data from the nuclear ribosomal ITS and chloroplast trnL-F region for all 21 Pachypodium species to reconstruct evolutionary relationships within the genus. We compare phylogenetic results to previous taxonomic classifications and geography. Results support three infrageneric taxa from the most recent classification of Pachypodium, and suggest that a group of African species (P. namaquanum, P. succulentum and P. bispinosum may deserve taxonomic recognition as an infrageneric taxon. However, our results do not resolve relationships among major African and Malagasy lineages of the genus.Conclusions/Significance. We present the first molecular phylogenetic analysis of Pachypodium. Our work has revealed five distinct lineages, most of which correspond to groups recognized in past taxonomic classifications. Our work also suggests that there is a complex biogeographic relationship between Pachypodium of Africa and Madagascar.

Elliptic genus of singular algebraic varieties and quotients

Science.gov (United States)

Libgober, Anatoly

2018-02-01

This paper discusses the basic properties of various versions of the two-variable elliptic genus with special attention to the equivariant elliptic genus. The main applications are to the elliptic genera attached to non-compact GITs, including the theories regarding the elliptic genera of phases on N  =  2 introduced in Witten (1993 Nucl. Phys. B 403 159-222).

A revision of the genus Microtypus Ratzeburg (Hymenoptera: Braconidae)

NARCIS (Netherlands)

Čapek, M.; Achterberg, van C.

1992-01-01

The genus Microtypus Ratzeburg, 1848 (Braconidae: Microtypinae) is revised, its species are keyed, and a new species, M. petiolatus van Achterberg spec. nov. is described. The type species is redescribed and fully illustrated. The genus Similearinus Glowacki & Karpinski, 1967 is a new junior synonym

KOSTERMANSIA SOEGENG A NEW GENUS IN BGMBACACEAE (Durioneae*

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W. SOEGENG REKSODIHARDJO

1959-06-01

Full Text Available In working up the genus Coelostegia, I received on loan from the ForestResearch Institute at Kepong, Malaya abundant material of a species whichWyatt-Smith was unable to place. Dr. Kostermans pointed out to me thatmost likely the specimens belonged to a new genus, related to CoelostegiaI have taken the liberty to name the genus after Dr. A. J. G. H. Kostermanswho has been devoting time and energy teaching me taxonomy, and whoJias taken up the burden of the development of taxonomic botany in In-donesia.I am indebted to Prof. Dr. C. G. G. J. van Steenis and to Dr. R. GBakhuizen van den Brink Jr., who have kindly helped me in preparing theLatin diagnoses.

Nucleotides, micro- and macro-nutrients, limonoids, flavonoids, and hydroxycinnamates composition in the phloem sap of sweet orange.

Science.gov (United States)

Hijaz, Faraj; Manthey, John A; Van der Merwe, Deon; Killiny, Nabil

2016-06-02

Currently, the global citrus production is declining due to the spread of Huanglongbing (HLB). HLB, otherwise known as citrus greening, is caused by Candidatus Liberibacter asiaticus (CLas) and is transmitted by the Asian citrus psyllids (ACP), Diaphorina citri Kuwayama. ACP transmits CLas bacterium while feeding on the citrus phloem sap. Multiplication of CLas in the phloem of citrus indicates that the sap contains all the essential nutrients needed for CLas. In this study, we investigated the micro- and macro-nutrients, nucleotides, and others secondary metabolites of phloem sap from pineapple sweet orange. The micro- and macro-nutrients were analyzed using inductively coupled plasma-mass spectroscopy (ICP-MS) and inductively coupled plasma-optical emission spectroscopy (ICP-OES). Nucleotides and other secondary metabolites analysis was accomplished by reversed phase HPLC coupled with UV, fluorescence detection, or negative mode electrospray ionization mass spectrometry (ESI-MS). Calcium (89 mM) was the highest element followed by potassium (38.8 mM) and phosphorous (24 mM). Magnesium and sulfur were also abundant and their concentrations were 15 and 9 mM, respectively. The rest of the elements were found in low amounts (sap.

Population genetic structure of Diaphorina citri Kuwayama (Hemiptera: Liviidae): host-driven genetic differentiation in China.

Science.gov (United States)

Meng, Lixue; Wang, Yongmo; Wei, Wen-Hua; Zhang, Hongyu

2018-01-24

The Asian citrus psyllid Diaphorina citri Kuwayama is a major pest in citrus production, transmitting Candidatus Liberibacter asiaticus. It has spread widely across eastern and southern China. Unfortunately, little is known about the genetic diversity and population structure of D. citri, making pest control difficult. In this study, nine specifically developed SSR markers and three known mitochondrial DNA were used for population genetics study of D. citri using 225 samples collected from all 7 distribution regions in China. Based on the SSR data, D. citri was found highly diverse with a mean observed heterozygosity of 0.50, and three subgroups were structured by host plant: (i) Shatangju, NF mandarin and Ponkan; (ii) Murraya paniculata and Lemon; (iii) Citrus unshiu, Bingtangcheng, Summer orange and Navel. No significant genetic differences were found with mtDNA data. We suggested the host-associated divergence is likely to have occurred very recently. A unimodal distribution of paired differences, the negative and significant Tajima's D and Fu's F S parameters among mtDNA suggested a recent demographic expansion. The extensive citrus cultivation and increased suitable living habitat was recommended as a key for this expansion event.

A taxonomic revision of the genus Podocarpus

OpenAIRE

Laubenfels, de, D.J.

1985-01-01

In connection with the forthcoming revision of the Coniferae for the Flora Malesiana, the author thought it necessary to revise the genus Podocarpus. Although this genus has a substantial representation in Malesia (30 species), the revision is too involved to be appropriate with the Flora Malesiana per se. One new subgenus and 17 new sections are described, and 94 species are enumerated, of which 11 species and 1 variety are described as new, and 3 varieties have been raised to specific rank....

Seiridium (Sporocadaceae): an important genus of plant pathogenic fungi

NARCIS (Netherlands)

Bonthond, G.; Sandoval-Denis, M.; Groenewald, J.Z.; Crous, P.W.

2018-01-01

The genus Seiridium includes multiple plant pathogenic fungi well-known as causal organisms of cankers on Cupressaceae. Taxonomically, the status of several species has been a topic of debate, as the phylogeny of the genus remains unresolved and authentic ex-type cultures are mostly absent. In the

A review of the genus Orionis Shaw (Hymenoptera: Braconidae: Euphorinae) and first records of the genus from South America and the Oriental Region.

Science.gov (United States)

Bortoni, Marco Aurélio; Shimbori, Eduardo Mitio; Shaw, Scott Richard; Souza-Gessner, Carolina DA Silva; Penteado-Dias, Angélica Maria

2016-12-16

Orionis is a small Neotropical euphorine genus, currently in the tribe Perilitini. Although the biology of the genus is unknown, Orionis eximius (Muesebeck) was described from a single female specimen reared from a cocoon associated with Lantana camara. Here, we present a taxonomic revision of Orionis and the first records of the genus from South America and Thailand, with descriptions of three new species: O. brasiliensis sp. nov., O. ecuadoriensis sp. nov. and O. orientalis sp. nov. We also report the first record of O. eximius from South America (Ecuador). A revised key for the described species is presented.

Nomenclatural realignment of Neotyphodium species with genus Epicholë.

Science.gov (United States)

Leuchtmann, Adrian; Bacon, Charles W; Schardl, Christopher L; White, James F; Tadych, Mariusz

2014-01-01

Nomenclatural rule changes in the International Code of Nomenclature for algae, fungi and plants, adopted at the 18th International Botanical Congress in Melbourne, Australia, in 2011, provide for a single name to be used for each fungal species. The anamorphs of Epichloë species have been classified in genus Neotyphodium, the form genus that also includes most asexual Epichloë descendants. A nomenclatural realignment of this monophyletic group into one genus would enhance a broader understanding of the relationships and common features of these grass endophytes. Based on the principle of priority of publication we propose to classify all members of this clade in the genus Epichloë. We have reexamined classification of several described Epichloë and Neotyphodium species and varieties and propose new combinations and states. In this treatment we have accepted 43 unique taxa in Epichloë, including distinct species, subspecies, and varieties. We exclude from Epichloë the two taxa Neotyphodium starrii, as nomen dubium, and Neotyphodium chilense, as an unrelated taxon.

Is it time to retire the genus Rymovirus from the family Potyviridae?

Science.gov (United States)

Ward, Colin W

2017-07-01

In the most recent Report of the International Committee on Taxonomy of Viruses (9 th Report, 2011) (King et al., Virus Taxonomy, Elsevier, New York, 2011) the family Potyviridae is described as comprising seven genera - Potyvirus, Ipomovirus, Macluravirus, Rymovirus, Tritimovirus, Brambyvirus and Bymovirus - despite previous suggestions questioning the validity of the taxonomic status of the genus Rymovirus. Since then the ICTV website records that an eighth genus Poacevirus has been approved for the Potyviridae family. The creation of the genus Rymovirus at the 1990 Potyvirus Taxonomy Workshop in Braunschweig, Germany was based on two things: (i) the incorrect assumption that the genomes of all mite-transmitted members of the Potyviridae would have strong sequence similarity to that of wheat streak mosaic virus, the only mite-transmitted member of this genus for which sequence data were available at that time, and (ii) that the genus should be named Rymovirus (based on a virus for which there was no sequence information) rather than a name based on wheat streak mosaic virus (e.g., "Whestremovirus") because ryegrass mosaic virus (RGMV) was the first mite-transmitted virus to be described and thus should take precedence. When sequence data for RGMV became available in 1995, these data showed that RGMV was very different from wheat streak mosaic virus (WSMV) and should not be assigned to the same genus. WSMV was subsequently re-assigned to a new genus, Tritimovirus, while the genus Rymovirus was retained. In this author's opinion, this retention is not justified, and the removal of Rymovirus as a distinct genus in the family Potyviridae is recommended. There may be merit when assigning it to the genus Potyvirus in sequestering these viruses in a rymovirus subgroup, as is done with other potyviruses, to reflect their different mode of transmission.

Identification of candidate structured RNAs in the marine organism 'Candidatus Pelagibacter ubique'

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Schwalbach Michael S

2009-06-01

Full Text Available Abstract Background Metagenomic sequence data are proving to be a vast resource for the discovery of biological components. Yet analysis of this data to identify functional RNAs lags behind efforts to characterize protein diversity. The genome of 'Candidatus Pelagibacter ubique' HTCC 1062 is the closest match for approximately 20% of marine metagenomic sequence reads. It is also small, contains little non-coding DNA, and has strikingly low GC content. Results To aid the discovery of RNA motifs within the marine metagenome we exploited the genomic properties of 'Cand. P. ubique' by targeting our search to long intergenic regions (IGRs with relatively high GC content. Analysis of known RNAs (rRNA, tRNA, riboswitches etc. shows that structured RNAs are significantly enriched in such IGRs. To identify additional candidate structured RNAs, we examined other IGRs with similar characteristics from 'Cand. P. ubique' using comparative genomics approaches in conjunction with marine metagenomic data. Employing this strategy, we discovered four candidate structured RNAs including a new riboswitch class as well as three additional likely cis-regulatory elements that precede genes encoding ribosomal proteins S2 and S12, and the cytoplasmic protein component of the signal recognition particle. We also describe four additional potential RNA motifs with few or no examples occurring outside the metagenomic data. Conclusion This work begins the process of identifying functional RNA motifs present in the metagenomic data and illustrates how existing completed genomes may be used to aid in this task.

Karyotype evolution and species differentiation in the genus Rattus ...

African Journals Online (AJOL)

Rattus is the most studied genus all over the world but species of the genus are not thoroughly reported from Manipur. The present paper deals with the morphometric, cytotaxonomic and phylogenetic studies of Manipur, India. The different species of Rattus namely Rattus rattus, Rattus brunneusculus, Rattus tanezumi and ...

Notes on the genus Pirdana Distant, 1886 (Lepidoptera: Hesperiidae)

NARCIS (Netherlands)

Jong, de R.; Treadaway, C.G.

1993-01-01

In the Oriental genus Pirdana Distant, 1886, the new species P. fusca is described from Samar (E Philippines). The phylogeny of the genus is discussed and as a consequence the endemic Sulawesi taxon P. hyela ismene (Felder & Felder, [1867]) is given back its species rank, bringing the total number

Taxonomic revision of the afrotropical genus Megatrigon Johnson, 1898 (Diptera: Syrphidae)

DEFF Research Database (Denmark)

Doczkal, Dieter; Radenković, Snežana; Lyneborg, Leif

2016-01-01

The genus-group taxon Megatrigon Johnson, 1898, stat. nov., is revised and treated as a valid genus within the Merodontini (= Eumerini). Extensive diagnoses are given for the genus and for its three constituent species groups: argenteus group [11 spp.], nivalis group [monotypic], sexfasciatus group...

Two new species and a new phyllobothriid cestode genus from sharks of the genus Negaprion Whitley (Carcharhiniformes).

Science.gov (United States)

Ruhnke, T R; Workman, R E

2013-05-01

Alexandercestus n. g. (Cestoda: Tetraphyllidea) is erected for two cestode species found parasitising the two known species of lemon sharks (Carcharhiniformes: Negaprion spp.). This new genus differs from all other phyllobothriid genera except for Hemipristicola Cutmore, Theiss, Bennett & Cribb, 2011, Marsupiobothrium Yamaguti, 1952, Nandocestus Reyda, 2008, Orectolobicestus Ruhnke, Caira & Carpenter 2006, Orygmatobothrium Diesing, 1863, Paraorygmatobothrium Ruhnke, 1994 and Phyllobothrium van Beneden, 1849 in possessing uniloculate bothridia with an apical sucker and neck scutes. Alexandercestus differs from Orectolobicestus and Nandocestus in lacking marginal loculi on the bothridia, from Paraorygmatobothrium in possessing uninterrupted vitelline follicles at the level of the ovary and from Phyllobothrium in being euapolytic as opposed to anapolytic and in lacking posteriorly bifid bothridia. The new genus lacks the central accessory bothridial organ seen in specimens of Orygmatobothrium, and lacks the central bothridial accessory sucker of specimens of Marsupiobothrium. Alexandercestus spp. compare most favourably with specimens of Hemipristicola, especially with respect to aspects of proglottid morphology, but differ in possessing aristate gladiate spinitriches rather than serrate gladiate spinitriches on the proximal bothridial surface. In addition, the bothridia of Alexandercestus spp. are comparatively more fleshy and foliose than those in specimens of Hemipristicola. Two new species of Alexandercestus n. g. are described, Alexandercestus gibsoni n. sp. from Negaprion acutidens, collected from off northern Australia and the Marshall Islands, and Alexandercestus manteri n. sp. from N. brevirostris, collected off the islands of Bimini and the Florida Keys. The two new species differ in total length and vitelline follicle distribution. Bayesian inference and parsimony analysis of the D1-D3 region of the large nuclear ribosomal DNA of 17 published and seven

Phylogenetic relationship among East Asian species of the Stegana genus group (Diptera, Drosophilidae).

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Li, Tong; Gao, Jian-jun; Lu, Jin-ming; Ji, Xing-lai; Chen, Hong-wei

2013-01-01

The phylogenetic relationship among 27 East Asian species of the Stegana genus group was reconstructed using DNA sequences of mitochondrial (COI and ND2) and nuclear (28S) genes. The results lent support to the current generic/subgeneric taxonomic classification in the genus group with the exceptions of the paraphyly of the genus Parastegana and the subgenus Oxyphortica in the genus Stegana. The ancestral areas and divergence times in the genus group were reconstructed/estimated, and accordingly, the biogeographical history of this important clade was discussed. It was proposed that, the evolution of the plant family Fagaceae, especially Quercus, may have played a certain role in facilitating the diversification of the Stegana genus group. Copyright © 2012 Elsevier Inc. All rights reserved.

The amphipod genus Acidostoma

NARCIS (Netherlands)

Dahl, E.

1964-01-01

The genus Acidostoma was established by Lilljeborg (1865, p. 24) to receive Anonyx obesus Sp. Bate (1862, p. 74). Afterwards two further species have been added, viz. A. laticorne G. O. Sars (1879, p. 440) and A. nodiferum Stephensen (1923, p. 40). In the present paper it will be shown that A.

Genetic diversity within the genus Cynotilapia and its phylogenetic ...

African Journals Online (AJOL)

Cynotilapia's unicuspid teeth, a unique character used to delineate it from all other mbuna genera, leaves evolutionary biologists wondering which is the closest relative to this genus among mbuna cichlids. This genus has only two described species out of the 10-13 species/taxa, whereby the undescribed taxa are either ...

Phylogeny of the genus Morus (Urticales: Moraceae) inferred from ...

African Journals Online (AJOL)

Both nuclear ribosomal ITS and chloroplast trnL-F sequences were acquired from 13 mulberry genotypes belonging to nine species and three varieties, and one paper mulberry. The later belongs to genus B. papyrifera, designed as outgroup, and were analyzed. Within the genus Morus, the sequence diversity of ITS was ...

Proposal to restrict the genus Clostridium Prazmowski to Clostridium butyricum and related species.

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Lawson, Paul A; Rainey, Fred A

2016-02-01

The genus Clostridium as presently constituted is phylogenetically and phenotypically incoherent. Data from polyphasic taxonomic studies indicate that the genus comprises a collection of very heterogeneous species. Numerous phylogenetic studies, principally based on sequencing of the 16S rRNA gene, indicate that the genus Clostridium should be restricted to Clostridium cluster I as Clostridium sensu stricto . Despite these findings, authors continue to add novel species to the genus Clostridium that do not fall within the radiation of cluster I and the type species Clostridium butyricum , thus perpetuating the confusion associated with the taxonomy of this group. Here, we formally propose that members of the genus Clostridium Prazmowski be restricted to the type species C. butyricum and cluster I species. Eubacterium moniliforme , Eubacterium tarantellae , Sarcina maxima and Sarcina ventriculi should be transferred to the genus Clostridium as Clostridium moniliforme comb. nov., Clostridium tarantellae comb. nov., Clostridium maximum comb. nov. and Clostridium ventriculi comb. nov. A novel genus, Hathewaya gen. nov., is proposed for the species Clostridium histolyticum , Clostridium limosum and Clostridium proteolyticum as Hathewaya histolytica gen. nov. comb. nov., Hathewaya limosa comb. nov. and Hathewaya proteolytica comb. nov. The type species of the genus Hathewaya is Hathewaya histolytica.

Genotyping of clinical isolates of Acanthamoeba genus in Venezuela.

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Wagner, Carolina; Reyes-Batlle, María; Ysea, María Alejandra Vethencourt; Pérez, Mónica V Galindo; de Rondón, Carmen Guzmán; Paduani, Anaibeth J Nessi; Pérez, Angelyseb Dorta; López-Arencibia, Atteneri; Sifaoui, Ines; de Galindo, María Virginia Pérez; de Suárez, Eva Pérez; Martínez-Carretero, Enrique; Valladares, Basilio; Piñero, José E; Lorenzo-Morales, Jacob

2016-12-01

Free-living amoebae of Acanthamoeba genus are opportunistic pathogens distributed worldwide. Strains included in this genus are causative agents of a fatal encephalitis and a sight-threating keratitis in humans and other animals. In this study, 550 clinical samples which were collected between 1984 and 2014 from different patients with suspected infections due to Acanthamoeba were initially screened for the presence of this amoebic genus at the Laboratorio de Amibiasis-Escuela de Bioanálisis at the Universidad Central de Venezuela. Samples were cultured in 2% Non-Nutrient agar plates seeded with a layer of heat killed Escherichia coli. From the 550 clinical samples included in this study, 18 of them were positive for Acanthamoeba genus after culture identification. Moreover, positive samples were confirmed after amplification of the Diagnostic Fragment 3 (DF3) of the Acanthamoeba18S rDNA genus and sequencing was carried out in order to genotype the isolated strains of Acanthamoeba. Furthermore, the pathogenic potential of the strains was checked by performing thermotolerance and osmotolerance assays. Sequencing of the DF3 region resulted in the identification of genotype T4 in all the isolated strains. Moreover, most isolates were thermotolerant or both thermotolerant and osmotolerant and thus were classified as potentially pathogenic strains. To the best of our knowledge, this is the first report on the molecular characterization at the genotype level of Acanthamoeba strains in Venezuela.

Candidatus Phytoplasma brasiliense associado ao superbrotamento do hibisco (Hibiscus rosa-sinensis L. no Estado de São Paulo Candidatus Phytoplasma brasiliense associated with hibiscus witches' broom in the State of São Paulo-Brazil

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Eliane Gonçalves da Silva

2009-09-01

Full Text Available Plantas de hibisco com superbrotamento e definhamento seguido de morte têm sido observadas nos municípios de São Paulo, Campinas e Piracicaba. Como os sintomas são sugestivos daqueles induzidos por fitoplasmas, o presente trabalho buscou identificar o possível fitoplasma associado com a doença. Assim, 14 plantas sintomáticas de hibisco foram coletadas em Piracicaba (SP e submetidas ao PCR duplo com os primers P1/Tint-R16F2n/R2 e ao exame em microscópio eletrônico de transmissão. A identificação foi realizada por análise de RFLP com as enzimas de restrição BfaI, DraI, HaeIII, HhaI, HpaII, MboI, MseI, RsaI e TaqI. Testes de transmissão foram conduzidos com enxertia de ramos e uso de Cuscuta subinclusa. Os resultados de nested-PCR revelaram a presença consistente de fitoplasmas em todas as plantas sintomáticas e foram confirmados pela observação de corpúsculos pleomórficos no floema, através da microscopia eletrônica. A análise de RFLP mostrou que o fitoplasma encontrado em hibisco pertence ao grupo 16SrXV, o mesmo grupo do Candidatus Phytoplasma brasiliense. O fitoplasma foi transmitido de planta doente para sadia, tanto pela enxertia como pela C. subinclusa, demonstrando ser o agente do superbrotamento do hibisco.Ornamental hibiscus have been affected by shoot proliferation and decline followed by death in several cities in São Paulo State, especially São Paulo, Campinas and Piracicaba. As the symptoms are suggestives of those induced by phytoplasmas, the present work aimed to identify the possible phytoplasma associated with the disease. Fourteen symptomatic hibiscus were sampled in Piracicaba, submitted to nested-PCR with the primers P1/Tint-R16F2n/R2 and processed by transmission electron microscopy. The identification was made by RFLP analyses with the restriction enzymes BfaI, DraI, HaeIII, HhaI, HpaII, MboI, MseI, RsaI, and TaqI. Transmission assays were performed by grafting and Cuscuta subinclusa. The presence

Rickettsia parkeri and "Candidatus Rickettsia andeanae" in Questing Amblyomma maculatum (Acari: Ixodidae) From Mississippi.

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Lee, J K; Moraru, G M; Stokes, J V; Wills, R W; Mitchell, E; Unz, E; Moore-Henderson, B; Harper, A B; Varela-Stokes, A S

2017-03-01

Amblyomma maculatum Koch (Acari: Ixodidae), the primary vector for Rickettsia parkeri, may also be infected with a rickettsia of unknown pathogenicity, "Candidatus Rickettsia andeanae." Infection rates with these rickettsiae vary geographically, and coinfected ticks have been reported. In this study, infection rates of R. parkeri and "Ca. R. andeanae" were evaluated, and rickettsial DNA levels quantified, in 335 questing adult A. maculatum collected in 2013 (n = 95), 2014 (n = 139), and 2015 (n = 101) from Oktibbeha County, MS. Overall infection rates of R. parkeri and "Ca. R. andeanae" were 28.7% and 9.3%, respectively, with three additional A. maculatum (0.9%) coinfected. While R. parkeri-infected ticks were detected all three years (34.7% in 2013; 13.7% in 2014; 43.6% in 2015), "Ca. R. andeanae" was not detected in 2013, and was detected at rates of 10.8% in 2014, and 15.8% in 2015. Interestingly, rickettsial DNA levels in singly-infected ticks were significantly lower in "Ca. R. andeanae"-infected ticks compared to R. parkeri-infected ticks (P Rickettsia species in A. maculatum at the population level. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

CYANOBACTERIA OF THE GENUS PROCHLOROTHRIX

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Alexander Vasilievich Pinevich

2012-05-01

Full Text Available Green cyanobacteria are distinguished from blue-green ones by the possession of a chlorophyll-containing light harvesting antenna. Three genera of green cyanobacteria, namely Acaryochloris, Prochlorococcus and Prochloron, are unicellular and of marine habitat; Prochlorococcus marinus attracts most attention due to its outstanding role in prime productivity. The fourth genus, Prochlorothrix, is represented by filamentous freshwater strains. Unlike the rest of green cyanobacteria, Prochlorothrix is paradoxically rare: it has been isolated from two European locations only. Taking into account fluctuating blooms, morphological resemblance with Planktothrix and Pseudanabaena, and unsuccessful enrichment of Prochlorothrix, the preferred strategy of search for this cyanobacterium is based on PCR with natural DNA and specific primers. This approach already demonstrates a broader distribution of Prochlorothrix: marker genes have been found in at least two additional locations. Despite the growing evidence for naturally occurring Prochlorothrix, there are only a few cultivated strains, and only one of them (PCC 9006 is claimed to be axenic. In multixenic cultures, Prochlorothrix is accompanied by heterotrophic bacteria, indicating a consortium-type association. The genus Prochlorothrix includes two species: P. hollandica and P. scandica based on distinctions in genomic DNA, cell size, temperature optimum, and fatty acid composition of membrane lipids. In this short review, the properties of cyanobacteria of the genus Prochlorothrix are described, and the evolutionary scenario of green cyanobacteria, especially taking into account their role in the origin of simple chloroplast is given.

Giselia arizonica, a new genus and species of mite (Acaria: Tarsonemidae) associated with bark beetles of the genus Pseudopityophthorus (Coleoptera: Scolytidae) in North America

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Wojciech L. Magowski; Evert E. Lindquist; John C. Moser

2005-01-01

A new genus and species of the mite family Tarsonemidae, subfamily Tarsoneminae, is described and illustrated. Its systematic position among genera of Tarsoneminae and its host association with bark beetles of the genus Pseudopityophthorus Swaine, 1918 in North America are briefly discussed.

On the entropy of random surfaces with arbitrary genus

International Nuclear Information System (INIS)

Kostov, I.K.; Krzywicki, A.

1987-01-01

We calculate the susceptibility critical exponent γ for Polyakov random surfaces with arbitrary genus, using the Liouville theory to one-loop order. Some rigorous results obtained for special dimensionalities in a discrete version of the model are also noted. In all cases γ grows linearly with the genus of the surface. (orig.)

PCR identification of Fusarium genus based on nuclear ribosomal ...

African Journals Online (AJOL)

We have developed two taxon-selective primers for quick identification of the Fusarium genus. These primers, ITS-Fu-f and ITS-Fu-r were designed by comparing the aligned sequences of internal transcribed spacer regions (ITS) of a range of Fusarium species. The primers showed good specificity for the genus Fusarium, ...

The genus Architeuthis was erected, without giving any diagnosis ...

African Journals Online (AJOL)

spamer

The genus Architeuthis was erected, without giving any diagnosis, by Steenstrup in 1857 for a specimen stranded on the Danish coast in 1853. In 1880, Verrill gave the first description of the genus. Pfeffer (1912) related this history and also mentioned that traditional narratives and illustrations of the 16th century had.

Notes on the genus Punctelia in Denmark

DEFF Research Database (Denmark)

Christensen, Steen; Søchting, Ulrik

2007-01-01

establishing the genus Punctelia, did not re-combine P. ulophylla, nor include it in the accompanying key. She probably considered it as a synonym of P. subrudecta. In a study on European Punctelia species with lecanoric acid, van Herk & Aptroot (2000) accepted the taxon and made the combination Punctelia...... name at species level, proposed the combination Punctelia jeckeri, and lectotypified the name. As a preparatory work to a forthcoming revision of the Danish lichen checklist (Søchting & Alstrup 2007) it was decided to examine the Danish material of the genus Punctelia....

Genus-Wide Assessment of Lignocellulose Utilization in the Extremely Thermophilic Genus Caldicellulosiruptor by Genomic, Pangenomic, and Metagenomic Analyses.

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Lee, Laura L; Blumer-Schuette, Sara E; Izquierdo, Javier A; Zurawski, Jeffrey V; Loder, Andrew J; Conway, Jonathan M; Elkins, James G; Podar, Mircea; Clum, Alicia; Jones, Piet C; Piatek, Marek J; Weighill, Deborah A; Jacobson, Daniel A; Adams, Michael W W; Kelly, Robert M

2018-05-01

Metagenomic data from Obsidian Pool (Yellowstone National Park, USA) and 13 genome sequences were used to reassess genus-wide biodiversity for the extremely thermophilic Caldicellulosiruptor The updated core genome contains 1,401 ortholog groups (average genome size for 13 species = 2,516 genes). The pangenome, which remains open with a revised total of 3,493 ortholog groups, encodes a variety of multidomain glycoside hydrolases (GHs). These include three cellulases with GH48 domains that are colocated in the glucan degradation locus (GDL) and are specific determinants for microcrystalline cellulose utilization. Three recently sequenced species, Caldicellulosiruptor sp. strain Rt8.B8 (renamed here Caldicellulosiruptor morganii ), Thermoanaerobacter cellulolyticus strain NA10 (renamed here Caldicellulosiruptor naganoensis ), and Caldicellulosiruptor sp. strain Wai35.B1 (renamed here Caldicellulosiruptor danielii ), degraded Avicel and lignocellulose (switchgrass). C. morganii was more efficient than Caldicellulosiruptor bescii in this regard and differed from the other 12 species examined, both based on genome content and organization and in the specific domain features of conserved GHs. Metagenomic analysis of lignocellulose-enriched samples from Obsidian Pool revealed limited new information on genus biodiversity. Enrichments yielded genomic signatures closely related to that of Caldicellulosiruptor obsidiansis , but there was also evidence for other thermophilic fermentative anaerobes ( Caldanaerobacter , Fervidobacterium , Caloramator , and Clostridium ). One enrichment, containing 89.8% Caldicellulosiruptor and 9.7% Caloramator , had a capacity for switchgrass solubilization comparable to that of C. bescii These results refine the known biodiversity of Caldicellulosiruptor and indicate that microcrystalline cellulose degradation at temperatures above 70°C, based on current information, is limited to certain members of this genus that produce GH48 domain

Comparative Genomics Reveals High Genomic Diversity in the Genus Photobacterium

DEFF Research Database (Denmark)

Machado, Henrique; Gram, Lone

2017-01-01

was widespread and abundant in the genus, suggesting a role in genomic evolution. The high genetic variability and indications of genetic exchange make it difficult to elucidate genome evolutionary paths and raise the awareness of the roles of foreign DNA in the genomic evolution of environmental organisms.......Vibrionaceae is a large marine bacterial family, which can constitute up to 50% of the prokaryotic population in marine waters. Photobacterium is the second largest genus in the family and we used comparative genomics on 35 strains representing 16 of the 28 species described so far, to understand...... the genomic diversity present in the Photobacterium genus. Such understanding is important for ecophysiology studies of the genus. We used whole genome sequences to evaluate phylogenetic relationships using several analyses (16S rRNA, MLSA, fur, amino-acid usage, ANI), which allowed us to identify two...

A comparative morphological revision of the aphid genus Myzaphis van der Goot, 1913 (Insecta: Hemiptera: Aphididae) revealed a new genus and three new species.

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Kanturski, Mariusz; Barjadze, Shalva; Jensen, Andrew S; Wieczorek, Karina

2018-01-01

The aphid genus Myzaphis van der Goot, 1913 from the tribe Macrosiphini is revised to include eight species. Apterous and alate viviparous females, known fundatrices and known sexual morphs (oviparous females and males) of Myzaphis bucktoni, M. juchnevitschae, M. rosarum, M. tianshanica and M. turanica are re-described and illustrated. Lectotype and paralectotypes of Myzaphis bucktoni and M. turanica are designated. The status of M. komatsubarae nomen dubium is discussed. Myzaphis avariolosa is regarded as a species belonging to the genus Ericaphis. Three new species: M. oezdemirae Kanturski & Barjadze sp. nov., M. tuatayae Kanturski & Barjadze sp. nov. from Turkey and M. rezwanii Kanturski & Barjadze sp. nov. from Iran are described and illustrated. Myzaphis bucktoni is recorded from Portugal for the first time. Diagnosis of the genus Myzaphis van der Goot, 1913 is redefined and a new genus Richardsaphis Kanturski & Barjadze gen. nov. is erected with the type species R. canadensis (Richards) comb. nov. Richardsaphis is for the first time recorded from the USA and hitherto unknown oviparous female and alate male are described and illustrated. Original keys to species of the genus Myzaphis and aphid genera of the tribe Macrosiphini with 2-2-2 first tarsal chaetotaxy are also provided.

Florae Malesianae Precursores XXX. The genus Scleria in Malaysia

NARCIS (Netherlands)

Kern, J.H.

1961-01-01

After Boeckeler's treatise on the species of Scleria known in his day (5), no comprehensive study on the genus has ever been published. The preparation of an up-to-date monograph would be an arduous task, not only owing to the large size of the genus, but also to the numerous problems encountered in

Natural genetic variation in Calligonum Tunisian genus analyzed by ...

African Journals Online (AJOL)

The Calligonum genus is one of the most economically important resources of the Tunisian desert, playing an important role in the lives of desert local population. A great range of genetic diversity could be seen in diverse populations of this genus which are spread all over Tunisian areas. DNA-based molecular markers are ...

The species of the Neotropical genus Fractipons Townes, 1970 (Hymenoptera, Ichneumonidae, Cryptinae).

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Bordera, Santiago; González-Moreno, Alejandra

2011-01-19

In this paper, two new species of the Neotropical genus Fractipons Townes, 1970 (Hymenoptera, Ichneumonidae) are described. A new diagnosis for the genus, a re-description of Fractipons cincticornis Townes, 1970 and a key to known species are provided. New distribution records for the genus now include Argentina, Costa Rica, Panama and Peru.

The phyletic status of the genus Planaria (Platyhelminthes, Turbellaria, Tricladida)

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Ball, Ian R.; Gourbault, Nicole

1978-01-01

The amphiatlantic distribution of the genus Planaria is incompatible with our current hypothesis of the historical biogeography of freshwater planarians. New anatomical studies suggest the possibility that the genus is not strictly monophyletic; new karyological data are strongly corroborative of

A New Genus of Tapeworm (Cestoda: Onchoproteocephalidea) from Sawfish (Elasmobranchii: Pristidae).

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Caira, J N; Jensen, K; Fyler, C A

2018-04-01

Collections from the dwarf sawfish, Pristis clavata, near Darwin, Australia, in 1997 led to the discovery of the new onchoproteocephalidean genus Matticestus n. gen.-a taxon that has been referred to in molecular phylogenetic analyses in which it has been included as "New genus 8." Its type species, Matticestus anneae n. gen., n. sp., and a second species, Matticestus kathleenae n. sp., are described. Placement of this taxon in the Onchoproteocephalidea is supported morphologically in that both species bear a scolex with 4 bothridia each with a pair of bi-pronged hooks and spinitriches that extend throughout the length of the body. Sequence data for the D1-D3 region of the 28S rDNA gene also place the genus solidly among the other elasmobranch-hosted members of the order. The new genus differs from the other elasmobranch-hosted genera in the order in that its members possess a combination of biloculated bothridia with lateral lappets on the posterior margin of the anterior loculus and a pair of bi-pronged hooks with a distinctive configuration of tubercles and internal channels. Its members are also extremely small. In summary, Matticestus n. gen. is an unusually tiny, "spiny," genus of cestode that seems to exclusively parasitize sawfish of the genus Pristis.

Genus of total graphs from rings: A survey

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T. Tamizh Chelvam

2018-04-01

Full Text Available Let R be a commutative ring. The total graph T Γ ( R of R is the undirected graph with vertex set R and two distinct vertices x and y are adjacent if x + y is a zero divisor in R . In this paper, we present a survey of results on the genus of T Γ ( R and three of its generalizations. Keywords: Commutative ring, Total graph, Cayley graph, Genus, Planar

The genus Boschniakia in China: An ethnopharmacological and phytochemical review.

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Zhang, Le; Zhao, Yunshan; Wang, Zhipeng A; Wei, Kunhua; Qiu, Bin; Zhang, Chunhong; Wang-Müller, QiYan; Li, Minhui

2016-12-24

As a group of important medicine plants, Boschniakia rossica (Cham. et Schltdl) Fedtsch. and B. himalaica Hook．f．et Thoms, which are the only two species in the genus Boschniakia (Orobanchaceae), have long been used in traditional Chinese medicine for their multiple therapeutic uses related to enhanced renal function, erectile dysfunction, defaecate and hepatoprotective. Additionally, the two species are also used as dietary supplements in wine, cosmetics, and other healthy food. By providing comprehensive information and data of genus Boschniakia on botany, traditional medicinal uses, phytochemistry, pharmacological research and toxicology, this review aims to summary the group of natural compounds from Boschniakia discovered so far. The other aims are to reference research findings of their biological activities and functions in medicine, physiology, and cell biology to highlight the compound candidates which can be used for further drug discovery in several pharmaceutical areas including antioxidation, anticancer, anti-inflammation, anti-senile, and immunology. All of the available information on B. rossica and B. himalaica was collected from the electronic resources (such as PubMed, SciFinder Scholar, CNKI, TPL (www.theplantlist.org), Google Scholar, Baidu Scholar, and Web of Science). After a comprehensive analysis of the literatures from available online sources, the results show that both species of genus Boschniakia are valuable and popular herbal medicines with potentials to cure various ailments. The phytochemical studies revealed that the chemical compositions of this genus were mainly iridoid glycosides and phenylpropanoid glycosides. To date, 112 compounds have been isolated from the genus, while their crude extracts and purified compounds have been found to possess a wide range of biological activities including anti-senile, antitumor and anticancer, anti-inflammatory, protecting liver, boost memory, anti-oxidation, anti-lipid peroxidative, and

Bordasia Krapov., new Malvaceae genus

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Antonio Krapovickas

2003-01-01

Full Text Available Bordasia bicornis Krapov. new genus and species is described from northwestern ParaguayanChaco. It is related to Sida from which it differs by the mericarp with two apical horns, by theleaves dimorphic and coriaceous and by the fannel-shaped calyx

A new caddisfly genus (Trichoptera, Odontoceridae) from Vietnam

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Arefina-Armitage, Tatiana I.; Armitage, Brian J.

2010-01-01

Abstract Cephalopsyche, a new genus of caddisfly (Trichoptera, Odontoceridae), is described from Vietnam. Two new species are placed in the genus: Cephalopsyche gorgona sp. n. and Cephalopsyche neboissi sp. n. The adult male and female of each species exhibit distinct sexual dimorphism, especially in head morphology. In males, there are hinged, chamber-like structures on the vertex of the head, containing filamentous, columnar tissue when exposed. Descriptions and illustrations of both species are provided. PMID:21594025

A new caddisfly genus (Trichoptera, Odontoceridae from Vietnam

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Tatiana Arefina-Armitage

2010-10-01

Full Text Available Cephalopsyche, a new genus of caddisfly (Trichoptera, Odontoceridae, is described from Vietnam. Two new species are placed in the genus: Cephalopsyche gorgona sp. n. and Cephalopsyche neboissi sp. n. The adult male and female of each species exhibit distinct sexual dimorphism, especially in head morphology. In males, there are hinged, chamber-like structures on the vertex of the head, containing filamentous, columnar tissue when exposed. Descriptions and illustrations of both species are provided.

On genus-two solutions for the ILW equation

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Tutiya, Y.

2018-02-01

The existence of theta function solutions of genus two for the intermediate long-wave equation is established. A numerical example is also presented. The method basically goes along with Krichever's construction of theta function solutions for soliton equations, such as the Kronecker product equation. This idea leads us to a question whether a Riemann surface exists which allows a peculiar abelian integral of the third kind. The answer is affirmative at least for genus-two curves.

Notes on Malesian Fabaceae (Leguminosae-Papilionoideae) 16. The genus Mucuna

NARCIS (Netherlands)

Wiriadinata, H.; Ohashi, H.; Adema, F.

2016-01-01

The genus Mucuna is revised for the Flora Malesiana region. Several characters are discussed in some detail. The subdivision of the genus is discussed. We accept two subgenera: subg. Mucuna and subg. Stizolobium. Several groups of species showing similarity in some characters are discussed. A

Review of the Genus Pimpla (Hymenoptera: Ichneumonidae: Pimplinae from Korea

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Jin-Kyung Choi

2016-07-01

Full Text Available We reviewed Korean species of the genus Pimpla and confirmed 12 species. In this genus, 36 species have been reported from the Eastern Palaearctic region, eight species were from Korea. Also, we report four species, Pimpla albociliata Kasparyan, 1974, Pimpla femorella Kasparyan, 1974, Pimpla kaszabi (Momoi, 1973 and Pimpla melanacrias Perkins, 1941, which were newly recorded for the first time from Korea. Among them, Pimpla nipponica Uchida, 1928 is recorded from United States and the Nearctic region for the first time. A key to Korean species of the genus Pimpla, diagnoses and illustrations of adult external structures are provided.

On the toroidal compactifications of bosonic strings in higher genus

International Nuclear Information System (INIS)

Semikhatov, A.M.

1989-01-01

For the bosonic string in a higher genus, compactified on the maximal torus of a simply laced Lie group, we discuss a possibility to construct an operator formalism involving only those operators that are well-defined globally over the whole Riemann surface. We find, in particular, higher genus extensions of (some combinations of) the vertex operators for the Kac-Moody algebra. This allows us to derive the relation between the Sugawara and Virasoro constructions of the energy-momentum tensor on Riemann surfaces, and to propose an operator mechanism underlying the construction of group current correlation functions in higher genus. (orig.)

Diospyros, an under-utilized, multi-purpose plant genus: A review.

Science.gov (United States)

Rauf, Abdur; Uddin, Ghias; Patel, Seema; Khan, Ajmal; Halim, Sobia Ahsan; Bawazeer, Saud; Ahmad, Khalid; Muhammad, Naveed; Mubarak, Mohammad S

2017-07-01

The genus Diospyros from family Ebenaceae has versatile uses including edible fruits, valuable timber, and ornamental uses. The plant parts of numerous species have been in use as remedies in various folk healing practices, which include therapy for hemorrhage, incontinence, insomnia, hiccough, diarrhea etc. Phytochemical constituents such as terpenoids, ursanes, lupanes, polyphenols, tannins, hydrocarbons, and lipids, benzopyrones, naphthoquinones, oleananes, and taraxeranes have been isolated from different species of this genus. The biological activities of these plants such as antioxidant, anti-inflammatory, analgesic, antipyretic, anti-diabetic, antibacterial, anthelmintic, antihypertensive, cosmeceutical, enzyme-inhibitory etc. have been validated by means of an in vitro, in vivo, and clinical tests. As a rich reserve of pharmacologically important components, this genus can accelerate the pace of drug discovery. Accordingly, the aim of the present review is to survey and summarize the recent literature pertaining to the medicinal and pharmacological uses of Diospyros, and to select experimental evidence on the pharmacological properties of this genus. In addition, the review also aims at identifying areas that need development to make use of this genus, especially its fruit and phytochemicals as means for economic development and for drug discovery. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Phylogenomics and Comparative Genomic Studies Robustly Support Division of the Genus Mycobacterium into an Emended Genus Mycobacterium and Four Novel Genera.

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Gupta, Radhey S; Lo, Brian; Son, Jeen

2018-01-01

The genus Mycobacterium contains 188 species including several major human pathogens as well as numerous other environmental species. We report here comprehensive phylogenomics and comparative genomic analyses on 150 genomes of Mycobacterium species to understand their interrelationships. Phylogenetic trees were constructed for the 150 species based on 1941 core proteins for the genus Mycobacterium , 136 core proteins for the phylum Actinobacteria and 8 other conserved proteins. Additionally, the overall genome similarity amongst the Mycobacterium species was determined based on average amino acid identity of the conserved protein families. The results from these analyses consistently support the existence of five distinct monophyletic groups within the genus Mycobacterium at the highest level, which are designated as the " Tuberculosis-Simiae ," " Terrae," " Triviale ," " Fortuitum-Vaccae ," and " Abscessus-Chelonae " clades. Some of these clades have also been observed in earlier phylogenetic studies. Of these clades, the " Abscessus-Chelonae" clade forms the deepest branching lineage and does not form a monophyletic grouping with the " Fortuitum-Vaccae " clade of fast-growing species. In parallel, our comparative analyses of proteins from mycobacterial genomes have identified 172 molecular signatures in the form of conserved signature indels and conserved signature proteins, which are uniquely shared by either all Mycobacterium species or by members of the five identified clades. The identified molecular signatures (or synapomorphies) provide strong independent evidence for the monophyly of the genus Mycobacterium and the five described clades and they provide reliable means for the demarcation of these clades and for their diagnostics. Based on the results of our comprehensive phylogenomic analyses and numerous identified molecular signatures, which consistently and strongly support the division of known mycobacterial species into the five described clades, we

Development of DNA barcodes of genus Lygus Hahn (Hemiptera: Miridae)

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The genus Lygus (Hemiptera: Miridae) is an important group of insects that contains 43 known species worldwide. Some species within this genus are important agricultural pests in North America. Annual economic impacts in cotton, Gossypium hirsutum L., from Lygus spp. due to yield losses and control ...

The genus Nonomuraea: A review of a rare actinomycete taxon for novel metabolites.

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Sungthong, Rungroch; Nakaew, Nareeluk

2015-05-01

The genus Nonomuraea is a rare actinomycete taxon with a long taxonomic history, while its generic description was recently emended. The genus is less known among the rare actinomycete genera as its taxonomic position was revised several times. It can be found in diverse ecological niches, while most of its member species were isolated from soil samples. However, new trends to discover the genus in other habitats are increasing. Generic abundance of the genus was found to be dependent on geographical changes. Novel sources together with selective and invented isolation techniques might increase a chance to explore the genus and its novel candidates. Interestingly, some of its members have been revealed as a valuable source of novel metabolites for medical and industrial purposes. Broad-range of potent bioactive compounds including antimicrobial, anticancer, and antipsychotic substances, broad-spectrum antibiotics and biocatalysts can be synthesized by the genus. In order to investigate biosynthetic pathways of the bioactive compounds and self-resistant mechanisms to these compounds, the links from genes to metabolites have yet been needed for further discovery and biotechnological development of the genus Nonomuraea. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

On the elliptic genus of three E-strings and heterotic strings

International Nuclear Information System (INIS)

Cai, Wenhe; Huang, Min-xin; Sun, Kaiwen

2015-01-01

A precise formula for the elliptic genus of three E-strings is presented. The related refined free energy coincides with the result calculated from topological string on local half K3 Calabi-Yau threefold up to genus twelve. The elliptic genus of three heterotic strings computed from M9 domain walls matches with the result from orbifold formula to high orders. This confirms the n=3 case of the recent conjecture that n pairs of E-strings can recombine into n heterotic strings.

The genus Actiniceps Berk. & Br

NARCIS (Netherlands)

Boedijn, K.B.

1959-01-01

The genus Actiniceps Berk. & Br. is shown to be a Basidiomycete. Wiesnerina Höhn. and Dimorphocystis Corner are regarded synonymous. The type species A. thwaitesii Berk. & Br. is redescribed with D. capitatus Corner as synonym. The following new combinations are proposed: A. horrida (Höhn.) Boedijn,

Notes on Malesian Fabaceae (Leguminosae-Papilionoideae) 17. The genus Dalbergia

NARCIS (Netherlands)

Adema, F.; Ohashi, H.; Sunarno, B.

2016-01-01

A systematic treatment of the genus Dalbergia for the Flora Malesiana (FM) region is presented. The treatment includes a genus description, two keys to the species, an enumeration of the species present in the FM-area with names and synonyms, details of distribution, habitat and ecology and where

On the identity of two new species of the genus coleoscirus (acari: cunaxidae) with annotations on the genus from pakistan

International Nuclear Information System (INIS)

Bashir, M.H.; Ashfaq, M.

2008-01-01

Adult females of two new Cunaxid mites, Coleoscirus raviensis n.sp. and Coleoscirus tobaensis n.sp. were collected during the taxonomic exploration of the mite fauna of the family Cunaxidae from Punjab- Pakistan. The new species were compared with 9 already describes species of the same genus from Pakistan. A Comprehensive key of all the known species of this genus from Pakistan has been prepared to incorporate the new species. A ceremonial description and illustration of main body characteristics, geographical distribution, host range and distinguishing remarks are also given. (author)

The pangenome of the genus Clostridium.

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Udaondo, Zulema; Duque, Estrella; Ramos, Juan-Luis

2017-07-01

The pangenome for the genus Clostridium sensu stricto, which was obtained using highly curated and annotated genomes from 16 species is presented; some of these cause disease, while others are used for the production of added-value chemicals. Multilocus sequencing analysis revealed that species of this genus group into at least two clades that include non-pathogenic and pathogenic strains, suggesting that pathogenicity is dispersed across the phylogenetic tree. The core genome of the genus includes 546 protein families, which mainly comprise those involved in protein translation and DNA repair. The GS-GOGAT may represent the central pathway for generating organic nitrogen from inorganic nitrogen sources. Glycerol and glucose metabolism genes are well represented in the core genome together with a set of energy conservation systems. A metabolic network comprising proteins/enzymes, RNAs and metabolites, whose topological structure is a non-random and scale-free network with hierarchically structured modules was built. These modules shed light on the interactions between RNAs, proteins and metabolites, revealing biological features of transcription and translation, cell wall biosynthesis, C1 metabolism and N metabolism. Network analysis identified four nodes that function as hubs and bottlenecks, namely, coenzyme A, HPr kinases, S-adenosylmethionine and the ribonuclease P-protein, suggesting pivotal roles for them in Clostridium. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Ethnomedicinal uses, phytochemistry and pharmacological properties of the genus Boerhavia.

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Patil, Kapil S; Bhalsing, Sanjivani R

2016-04-22

The genus Boerhavia is widely distributed in tropical, subtropical and temperate regions of the world including Mexico, America, Africa, Asia, Indian Ocean Islands, Pacific Islands and Australia. The genus Boerhavia is extensively used by local peoples and medicinal practitioners for treatments of hepatitis, urinary disorders, gastro intestinal diseases, inflammations, skin problems, infectious diseases and asthma. Present review focused on traditional uses, phytochemistry, pharmacology and toxicology of Boerhavia genus to support potential scope for advance ethnopharmacological study. Information on the Boerhavia species was collected from classical books on medicinal plants, pharmacopoeias and scientific databases like PubMed, Scopus, GoogleScholar, Web of Science and others. Also scientific literatures based on ethnomedicinal surveys, Ph.D. and M.Sc. dissertations, published papers from Elsevier, Taylor and Francis, Springer, ACS as well as Wiley publishers and reports by government bodies and documentations were assessed. A total of 180 compounds from Boerhavia genus were isolated of which B. diffusa alone shared around 131 compounds and for most of which it is currently an exclusive source. In the genus, phenolic glycosides and flavonoids contribute approximately 97 compounds. These includes eupalitin, rotenoids like boeravinones, coccineons, alkaloid i.e. betanin and punarnavine etc., showing vital pharmaceutical activities such as anticancer, anti-inflammatory, antioxidant and immunomodulatory. Boerhavia is an important genus with wide range of medicinal uses. However, most of the available scientific literatures have lacked relevant doses, duration and positive controls for examining bioefficacy of extracts and its active compounds. In some studies, taxonomic errors were encountered. Moreover, there is need for accurate methods in testing the safety and ethnomedicinal validity of Boerhavia species. Copyright © 2016. Published by Elsevier Ireland Ltd.

Comparative Genomics Reveals High Genomic Diversity in the Genus Photobacterium.

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Machado, Henrique; Gram, Lone

2017-01-01

Vibrionaceae is a large marine bacterial family, which can constitute up to 50% of the prokaryotic population in marine waters. Photobacterium is the second largest genus in the family and we used comparative genomics on 35 strains representing 16 of the 28 species described so far, to understand the genomic diversity present in the Photobacterium genus. Such understanding is important for ecophysiology studies of the genus. We used whole genome sequences to evaluate phylogenetic relationships using several analyses (16S rRNA, MLSA, fur , amino-acid usage, ANI), which allowed us to identify two misidentified strains. Genome analyses also revealed occurrence of higher and lower GC content clades, correlating with phylogenetic clusters. Pan- and core-genome analysis revealed the conservation of 25% of the genome throughout the genus, with a large and open pan-genome. The major source of genomic diversity could be traced to the smaller chromosome and plasmids. Several of the physiological traits studied in the genus did not correlate with phylogenetic data. Since horizontal gene transfer (HGT) is often suggested as a source of genetic diversity and a potential driver of genomic evolution in bacterial species, we looked into evidence of such in Photobacterium genomes. Genomic islands were the source of genomic differences between strains of the same species. Also, we found transposase genes and CRISPR arrays that suggest multiple encounters with foreign DNA. Presence of genomic exchange traits was widespread and abundant in the genus, suggesting a role in genomic evolution. The high genetic variability and indications of genetic exchange make it difficult to elucidate genome evolutionary paths and raise the awareness of the roles of foreign DNA in the genomic evolution of environmental organisms.

Computational identification of strain-, species- and genus-specific proteins

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Thiagarajan Rathi

2005-11-01

Full Text Available Abstract Background The identification of unique proteins at different taxonomic levels has both scientific and practical value. Strain-, species- and genus-specific proteins can provide insight into the criteria that define an organism and its relationship with close relatives. Such proteins can also serve as taxon-specific diagnostic targets. Description A pipeline using a combination of computational and manual analyses of BLAST results was developed to identify strain-, species-, and genus-specific proteins and to catalog the closest sequenced relative for each protein in a proteome. Proteins encoded by a given strain are preliminarily considered to be unique if BLAST, using a comprehensive protein database, fails to retrieve (with an e-value better than 0.001 any protein not encoded by the query strain, species or genus (for strain-, species- and genus-specific proteins respectively, or if BLAST, using the best hit as the query (reverse BLAST, does not retrieve the initial query protein. Results are manually inspected for homology if the initial query is retrieved in the reverse BLAST but is not the best hit. Sequences unlikely to retrieve homologs using the default BLOSUM62 matrix (usually short sequences are re-tested using the PAM30 matrix, thereby increasing the number of retrieved homologs and increasing the stringency of the search for unique proteins. The above protocol was used to examine several food- and water-borne pathogens. We find that the reverse BLAST step filters out about 22% of proteins with homologs that would otherwise be considered unique at the genus and species levels. Analysis of the annotations of unique proteins reveals that many are remnants of prophage proteins, or may be involved in virulence. The data generated from this study can be accessed and further evaluated from the CUPID (Core and Unique Protein Identification system web site (updated semi-annually at http://pir.georgetown.edu/cupid. Conclusion CUPID

Early Homo and the role of the genus in paleoanthropology.

Science.gov (United States)

Villmoare, Brian

2018-01-01

The history of the discovery of early fossils attributed to the genus Homo has been contentious, with scholars disagreeing over the generic assignment of fossils proposed as members of our genus. In this manuscript I review the history of discovery and debate over early Homo and evaluate the various taxonomic hypotheses for the genus. To get a sense of how hominin taxonomy compares to taxonomic practice outside paleoanthropology, I compare the diversity of Homo to genera in other vertebrate clades. Finally, I propose a taxonomic model that hews closely to current models for hominin phylogeny and is consistent with taxonomic practice across evolutionary biology. © 2018 American Association of Physical Anthropologists.

Abradeosporangium, a new genus of Mucorales (Fungi: Zygomycetes from India

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A. Subrahmanyam

2010-09-01

Full Text Available Abradeosporangium, a new genus of Mucorales with its type species A. variosporum, is described from India. The new genus is distinct in producing dimorphic sporangia and multispored, acolumellate and globose macrosporangia with persistent, thin peridium. Sparingly, portions of the sporangial wall at the top and bottom of the sporangia are dissolved at maturity to release the sporangiospores whilst, in its close ally Gilbertella, the sporangium breaks open via a longitudinal suture. Further, the smaller sporangia (microsporangia are without a longitudinal suture and produce variable number of spores. The sporangiospores are pale brown, longitudinally striated without any appendages. Besides, the new genus produces neither rhizoids nor zygospores.

Standardized gene nomenclature for the Brassica genus

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King Graham J

2008-05-01

Full Text Available Abstract The genus Brassica (Brassicaceae, Brassiceae is closely related to the model plant Arabidopsis, and includes several important crop plants. Against the background of ongoing genome sequencing, and in line with efforts to standardize and simplify description of genetic entities, we propose a standard systematic gene nomenclature system for the Brassica genus. This is based upon concatenating abbreviated categories, where these are listed in descending order of significance from left to right (i.e. genus – species – genome – gene name – locus – allele. Indicative examples are provided, and the considerations and recommendations for use are discussed, including outlining the relationship with functionally well-characterized Arabidopsis orthologues. A Brassica Gene Registry has been established under the auspices of the Multinational Brassica Genome Project that will enable management of gene names within the research community, and includes provisional allocation of standard names to genes previously described in the literature or in sequence repositories. The proposed standardization of Brassica gene nomenclature has been distributed to editors of plant and genetics journals and curators of sequence repositories, so that it can be adopted universally.

Biological activities of species in the genus Tulbaghia : A review ...

African Journals Online (AJOL)

Species of the genus Tulbaghia has been widely used in traditional medicine to treat various ailments such rheumatism, fits, fever, earache, tuberculosis etc. It is believed that the species possess several therapeutic properties. This paper evaluates some of the biological activities of the genus Tulbaghia. It is evident from ...

Calongea, a new genus of truffles in the Pezizaceae (Pezizales)

Science.gov (United States)

Rosanne A. Healy; Gregory Bonito; James M. Trappe

2009-01-01

Phylogenetic analysis of the ITS and LSU rDNA of Pachyphloeus species from Europe and North America revealed a new truffle genus. These molecular analyses plus sequences downloaded from a BLAST search in GenBank indicated that Pachyphloeus prieguensis is within the Pezizaceae but well outside of the genus Pachyphloeus...

[Taxonomy and evolution of the genus Pratylenchoides (Nematoda: Pratylenchidae)].

Science.gov (United States)

Ryss, A Iu

2007-01-01

The amended diagnosis of the genus Pratylenchoides and list of its valid species with synonyms are given. All the efficient diagnostic characters are listed. Modern taxonomic standard for the description of Pratylenchoides species is proposed; it may be used also in taxonomic databases. Tabular and text keys for all species of the genus are given. Five following groups are considered within the genus Pratylenchoides. The group arenicola differs from other groups in the primitive adanal bursa type; the groups magnicauda, crenicauda, ritteri, and megalobatus differ from each other in the position of cardium along the body axis in relation to the pharyngeal gland nuclei, pharynx types are named according to the stages of its evolution from the primitive tylenchoid pharynx (cardium situated posteriorly) to the advanced hoplolaimoid one (cardium situated anteriorly). Diagnoses and species compositions of the groups are given. Basing on the matrix of species characters, the dendrogram has been generated for all species of Pratylenchoides and for all characters (UPGMA, distance, mean character difference, random, characters ordered). Taking in view that the PAUP software gives equal weights to all characters, including the most important ones which define the prognostic species groups, the separate dendrograms for each prognostic species group were generated using the same above mentioned tree parameters. On the base of the records of Pratylenchoides species the matrices of plant host ranges, geographic distribution, and preferred soil-climatic conditions were developed. The dendrograms of the faunal similarities were generated using these matrices, with conclusions on a possible origin and evolution of the genus. The genus evolved from the flood lands with swampy soils and prevalence of dicotyledons (herbaceous Lamiaceae and woody Salicaceae families) to the forest mainland communities with balanced humidity and predominance of herbaceous Poaceae and Fabaceae with woody

Phenetic analysis of medicinally important species of the genus solanum from Pakistan

International Nuclear Information System (INIS)

Yousaf, Z.; Shinwari, Z.K.; Khan, M.A.

2010-01-01

Solanum is one of the largest and hyper diverse genera of the family Solanaceae. In Pakistan Solanum is represented by 15 species, of which 11 species have the medicinal properties. Taxonomically this is a complex genus because of the presence of number of hybrid and controversial taxonomic status of S. nigrum complex. In the present study numerical techniques were utilized to evaluate the taxonomic status of the genus Solanum. Cluster analysis was employed to work out the relationship among the taxa of the genus Solanum. The Euclidean distance measured similarity matrix and a dendrogram was constructed by using the complete linkage method. This analysis showed that all the species of genus Solanum can easily be divided into two groups at hundred percentage linkage distance. Co-relation of quantitative characters showed that floral characters had highly significant relationship with the stem characters, these characters plays a significant role in the identification of the species of the genus Solanum. (author)

Eonandeva gen. nov., a new distinctive genus from Eocene Baltic amber (Diptera: Chironomidae).

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Zakrzewska, Marta; Giłka, Wojciech

2015-11-20

A new fossil genus, Eonandeva gen. nov., with two new species: E. helva sp. nov. (type for the genus) and E. latistyla sp. nov., is described from Eocene Baltic amber (~45-40 Ma). Adult males of both new species show the wing venation pattern, shape and chaetotaxy typical for the tribe Tanytarsini. The characters defined as prior apomorphies for the new genus--the gonostylus with a subapical flattened lobe and the stout, strongly elongated superior volsella--separate Eonandeva from the closely related extant genus Nandeva Wiedenbrug, Reiss et Fittkau, 1998.

Differential equation for genus-two characters in arbitrary rational conformal field theories

International Nuclear Information System (INIS)

Mathur, S.D.; Sen, A.

1989-01-01

We develop a general method for deriving ordinary differential equations for the genus-two ''characters'' of an arbitrary rational conformal field theory using the hyperelliptic representation of the genus-two moduli space. We illustrate our method by explicitly deriving the character differential equations for k=1 SU(2), G 2 , and F 4 WZW models. Our method provides an intrinsic definition of conformal field theories on higher genus Riemann surfaces. (orig.)

Taxonomy of the genus Cupriavidus: a tale of lost and found.

Science.gov (United States)

Vandamme, Peter; Coenye, Tom

2004-11-01

DNA-DNA hybridization experiments and an evaluation of phenotypic characteristics, DNA base ratios and 16S rRNA gene sequences demonstrated that Wautersia eutropha (Davies 1969) Vaneechoutte et al. 2004, the type species of the genus Wautersia, is a later synonym of Cupriavidus necator Makkar and Casida 1987, the type species of the genus Cupriavidus. In conformity with Rules 15, 17, 23a and 37a(1) of the International Code of Nomenclature of Bacteria, the genus name Cupriavidus has priority over the genus name Wautersia, and all other members of the genus Wautersia are reclassified into Cupriavidus as Cupriavidus basilensis comb. nov. (type strain LMG 18990(T)=DSM 11853(T)), Cupriavidus campinensis comb. nov. (type strain LMG 19282(T)=CCUG 44526(T)), Cupriavidus gilardii comb. nov. (type strain LMG 5886(T)=CCUG 38401(T)), Cupriavidus metallidurans comb. nov. (type strain LMG 1195(T)=DSM 2839(T)), Cupriavidus oxalaticus comb. nov. (type strain LMG 2235(T)=CCUG 2086(T)=DSM 1105(T)), Cupriavidus pauculus comb. nov. (type strain LMG 3244(T)=CCUG 12507(T)), Cupriavidus respiraculi comb. nov. (type strain LMG 21510(T)=CCUG 46809(T)) and Cupriavidus taiwanensis comb. nov. (type strain LMG 19424(T)=CCUG 44338(T)).

Taxonomic status and redescription of the genus Brasicystis Thatcher, 1979 (Digenea: Didymozoidae).

Science.gov (United States)

Melo, Francisco Tiago de Vasconcelos; Silva, Jefferson Pereira E; Gonçalves, Evonnildo Costa; Furtado, Adriano Penha; Giese, Elane Guerreiro; Santos, Cláudia Portes; Santos, Jeannie Nascimento

2013-04-01

Brasicystis bennetti Thatcher, 1979 was first described from specimens obtained from the subcutaneous tissues of the mouth and operculum of Plagioscyion squamosissimus from the Amazon River in Brazil, however since 2008, Brasicystis has been considered a genus inquirendum. This study reviews some of the diagnostic characters from the original description of B. bennetti from the Amazon Delta, and redescribes the genus and species with a discussion of their taxonomic status. Ultrastructural and molecular approaches complement the data presented on this monotypic genus. The diagnosis of the tribe Didymozoini Monticelli, 1888 is amended to incorporate the genus Brasicystis, which is redescribed and revalidated here, with the proposal of an amended key. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Higher Genus Abelian Functions Associated with Cyclic Trigonal Curves

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Matthew England

2010-03-01

Full Text Available We develop the theory of Abelian functions associated with cyclic trigonal curves by considering two new cases. We investigate curves of genus six and seven and consider whether it is the trigonal nature or the genus which dictates certain areas of the theory. We present solutions to the Jacobi inversion problem, sets of relations between the Abelian function, links to the Boussinesq equation and a new addition formula.

Chromosomes of parasitic wasps of the genus Metaphycus (Hymenoptera: Chalcidoidea: Encyrtidae

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Vladimir Gokhman

2010-07-01

Full Text Available Karyotypes of four species of the genus Metaphycus Mercet, 1917, namely, M. flavus (Howard, 1881 and M. luteolus (Timberlake, 1916 (both have n = 10 and 2n = 20, M. angustifrons Compere, 1957 (n = 9 and 2n = 18 and M. stanleyi Compere, 1940 (n = 5 and 2n = 10 were studied. The latter chromosome number, n = 5, is the lowest known one for the family Encyrtidae. A karyotype with n = 10 is considered ancestral for the genus Metaphycus. Karyotype evolution in this genus is likely to have occurred through chromosomal fusions.

The phenolic acids of some species of the Oenothera L. genus

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Tadeusz Krzaczek

2014-01-01

Full Text Available The occurence and approximative quantitative proportions of the phenolic acids in four species of the Oenothera L. genus was determined by the method of TLC and HPLC. In all species of Oenothera L. genus the permanent occurrence of acids: 2-hydroxy-4-metoxybenzoic, salicylic, ferulic, syringic, vanillic, p-coumaric, p-hydroxybenzoic, p-hydroxyphenylacetic, γ-rezorcil, gentysic, protocatechuic, caffeic and gallic has been confirmed. Whereas the other phenolic acids: o-coumaric, o-hydroxyphenylacetic and pirocatechuic were found in some species of the Oenothera L. genus only.

Swedish Plectida (Nematoda). Part 10. The genus Deontolaimus de Man, 1880.

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Holovachov, Oleksandr; Boström, Sven

2015-10-28

The genus Deontolaimus de Man, 1880 is revised and the genus Camacolaimus de Man, 1889 is considered a junior synonym of Deontolaimus based on re-examination of type material of Camacolaimus tardus de Man, 1889 and C. barbatus Warwick, 1970. Two known and three new species of Deontolaimus are described from bottom sediments collected in marine habitats of Sweden: Deontolaimus uniformis (Cobb, 1920) comb. n., D. longicauda (de Man, 1922) comb. n., Deontolaimus catalinae sp. n., D. paraguillei sp. n. and Deontolaimus timmi sp. n. Deontolaimus catalinae sp. n. is characterized by body length of 1.3-1.7 mm; anterior-most somatic sensilla located short distance posterior to amphid; cephalic sensilla equal to 0.2 labial region diameter in length; amphidial fovea ventrally-unispiral with one turn, located in front of cephalic sensilla bases; excretory pore located short distance posterior to onchiostyle base; onchiostyle with bluntly rounded tip and subcylindrical body; male with alveolar supplements extending from anterior end to middle of body, tubular supplements absent; spicules 36-40 µm long; and didelphic female reproductive system. Deontolaimus paraguillei sp. n. is characterized by body length of 1.4-1.8 mm; anterior-most somatic sensilla located at level with onchiostyle; cephalic sensilla equal to 0.2-0.3 labial region diameter in length; amphidial fovea ventrally-unispiral with one turn, located at level with cephalic sensilla bases; excretory pore located just posterior to nerve ring level; onchiostyle with bluntly rounded tip and subcylindrical body; male with alveolar supplements extending from anterior end to about three body diameters in front of cloaca, tubular supplements absent; spicules 42-46 µm long; and didelphic female reproductive system. Deontolaimus timmi sp. n. is characterized by body length of 0.7-0.9 mm; anterior-most somatic sensilla located at level with onchiostyle; cephalic sensilla equal to 0.2-0.3 labial region diameter in length

A review on ethnobotany, phytochemistry and pharmacology of plant genus Caralluma R. Br.

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Adnan, Muhammad; Jan, Saleem; Mussarat, Sakina; Tariq, Akash; Begum, Shaheen; Afroz, Anila; Shinwari, Zabta Khan

2014-10-01

Caralluma is a xerophytic genus used as traditional medicine for the treatment of diabetes, inflammation, leprosy, obesity and rheumatism. Objectives of this review are to establish a relationship between traditional uses and scientific studies by critically evaluating the available fragmented literature on ethnobotany, pharmacology, phytochemistry and toxicology of genus Caralluma. Ethnomedical uses of Caralluma have been recorded from various countries such as China, India, Iran and Pakistan for six major classes of diseases including diabetes and gastrointestinal disorders. This review indicated the efficacy of genus Caralluma in several in vitro and in vivo pharmacological properties such as antimicrobial, antioxidant and anticancer activity. These bioactivity might be due to the presence of certain classes of compounds in genus Caralluma including pregnane glycosides, flavonoid glycosides and flavones. Traditional uses and scientific evaluation of Caralluma indicates that it is one of the most widely used genus in some parts of the world. Further studies on the structural activity relationship of some of the isolated compound may improve their biological potency as well as scientific exploitation of traditional uses of the genus. © 2014 Royal Pharmaceutical Society.

Pollen Ultrastructure of Genus Dendrobium Orchids as a Learning Resource

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Lika Dwi Apriani

2016-11-01

Full Text Available Anggrek genus Dendrobium merupakan salah satu genus dari divisi spermatophyta yang merupakan kelompok tumbuhan yang berkembang dengan menggunakan biji. Tumbuhan berbiji tentu memiliki bunga sebagai alat perkembangan generatifnya. Perkembangan generatif pada bunga artinya pertemuan antara sel gamet jantan dan sel gamet betina. Sel gamet betina pada tumbuhan dihasilkan oleh putik, sedangkan sel gamet jantan disebut serbuk sari atau pollen. Genus Dendrobium merupakan salah satu kekayaan alam Indonesia, jumlahnya diperkirakan mencapai 275 spesies. Penelitian ini bertujuan untuk mengetahui bagaimana ultrastruktur pollen anggrek genus Dendrobium dari sepuluh spesies yang diamati menggunakan SEM. Jenis penelitian ini adalah deskriptif kualitatif. Hasil penelitian menunjukkan unit pollen untuk semua spesies yaitu kategori pollinia, sedangkan untuk polaritas pollen adalah apolar. Jenis aperture kesepuluh spesies yang diamati mempunyai aperture dengan pola yang tidak beraturan dan lebih dari enam yang disebut colpate. Bentuk pollen dari semua spesies yang diteliti bentuknya adalah subprolate hingga prolate dan ukuran pollen termasuk dalam kategori minuta hingga media. Ornamentasi pollen atau skluptur pollen tidak teridentifikasi dikarenakan ukuran pollen yang terlalu kecil, permukaan pollen terlihat kurang jelas. Sumber belajar yang digunakan adalah atlas.

Ethnobotany, chemistry, and biological activities of the genus Tithonia (Asteraceae).

Science.gov (United States)

Chagas-Paula, Daniela A; Oliveira, Rejane B; Rocha, Bruno A; Da Costa, Fernando B

2012-02-01

The genus Tithonia is an important source of diverse natural products, particularly sesquiterpene lactones, diterpenes, and flavonoids. The collected information in this review attempts to summarize the recent developments in the ethnobotany, biological activities, and secondary metabolite chemistry of this genus. More than 100 structures of natural products from Tithonia are reported in this review. The species that has been most investigated in this genus is T. diversifolia, from which ca. 150 compounds were isolated. Biological studies are described to evaluate the anti-inflammatory, analgesic, antimalarial, antiviral, antidiabetic, antidiarrhoeal, antimicrobial, antispasmodic, vasorelaxant, cancer-chemopreventive, cytotoxic, toxicological, bioinsecticide, and repellent activities. A few of these studies have been carried out with isolated compounds from Tithonia species, but the majority has been conducted with different extracts. The relationship between the biological activity and the toxicity of compounds isolated from the plants of this genus as well as T. diversifolia extracts still remains unclear, and mechanisms of action remain to be determined. Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich.

Formulae for Arithmetic on Genus 2 Hyperelliptic Curves

DEFF Research Database (Denmark)

Lange, Tanja

2005-01-01

The ideal class group of hyperelliptic curves can be used in cryptosystems based on the discrete logarithm problem. In this article we present explicit formulae to perform the group operations for genus 2 curves. The formulae are completely general but to achieve the lowest number of operations we...... treat odd and even characteristic separately. We present 3 different coordinate systems which are suitable for different environments, e.g. on a smart card we should avoid inversions while in software a limited number is acceptable. The presented formulae render genus two hyperelliptic curves very...

Genus Phyllanthus for chronic hepatitis B virus infection

DEFF Research Database (Denmark)

Liu, J; Lin, Haili; McIntosh, H

2001-01-01

To evaluate the efficacy and safety of genus Phyllanthus for chronic hepatitis B virus (HBV) infection we performed a systematic review of randomized clinical trials. Randomized trials comparing genus Phyllanthus vs. placebo, no intervention, general nonspecific treatment, other herbal medicine.......85-17.21) compared with placebo or no intervention. There was no significant difference on clearance of serum HBsAg, HBeAg and HBV DNA between Phyllanthus and IFN. Phyllanthus species were better than nonspecific treatment or other herbal medicines for the clearance of serum HBsAg, HBeAg, HBV DNA, and liver enzyme...

Bacteria of the genera Ehrlichia and Rickettsia in ticks of the family Ixodidae with medical importance in Argentina.

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Sebastian, Patrick S; Tarragona, Evelina L; Bottero, María N Saracho; Mangold, Atilio J; Mackenstedt, Ute; Nava, Santiago

2017-01-01

The aim of this study was to get an overview about the occurrence of bacteria from the genus Ehrlichia and Rickettsia in ixodid ticks with medical importance in Argentina. Therefore, in 2013 and 2014, free-living ticks were collected in different provinces of northern Argentina. These ticks were determined as Amblyomma sculptum, Amblyomma neumanni, Amblyomma parvum, Amblyomma triste, Amblyomma ovale, Amblyomma tonelliae and Haemaphysalis juxtakochi. All samples were tested to determine the infection with Ehrlichia spp. and Rickettsia spp. by PCR assays. Rickettsial DNA was detected in all tested tick species, with the exception of A. tonelliae. 'Candidatus Rickettsia amblyommii', 'Candidatus Rickettsia andeanae', and Rickettsia parkeri were found in A. neumanni, A. parvum, and A. triste, respectively. Another rickettsial species, Rickettsia bellii, was found in A. sculptum, A. ovale and H. juxtakochi. None of the tested ticks showed infection with Ehrlichia. The results of the study demonstrate that Rickettsia species belonging to the spotted fever group are associated with various species of Amblyomma throughout a wide area of northern Argentina, where cases of Amblyomma ticks biting humans are common.

Phylogenomics and Comparative Genomic Studies Robustly Support Division of the Genus Mycobacterium into an Emended Genus Mycobacterium and Four Novel Genera

Science.gov (United States)

Gupta, Radhey S.; Lo, Brian; Son, Jeen

2018-01-01

The genus Mycobacterium contains 188 species including several major human pathogens as well as numerous other environmental species. We report here comprehensive phylogenomics and comparative genomic analyses on 150 genomes of Mycobacterium species to understand their interrelationships. Phylogenetic trees were constructed for the 150 species based on 1941 core proteins for the genus Mycobacterium, 136 core proteins for the phylum Actinobacteria and 8 other conserved proteins. Additionally, the overall genome similarity amongst the Mycobacterium species was determined based on average amino acid identity of the conserved protein families. The results from these analyses consistently support the existence of five distinct monophyletic groups within the genus Mycobacterium at the highest level, which are designated as the “Tuberculosis-Simiae,” “Terrae,” “Triviale,” “Fortuitum-Vaccae,” and “Abscessus-Chelonae” clades. Some of these clades have also been observed in earlier phylogenetic studies. Of these clades, the “Abscessus-Chelonae” clade forms the deepest branching lineage and does not form a monophyletic grouping with the “Fortuitum-Vaccae” clade of fast-growing species. In parallel, our comparative analyses of proteins from mycobacterial genomes have identified 172 molecular signatures in the form of conserved signature indels and conserved signature proteins, which are uniquely shared by either all Mycobacterium species or by members of the five identified clades. The identified molecular signatures (or synapomorphies) provide strong independent evidence for the monophyly of the genus Mycobacterium and the five described clades and they provide reliable means for the demarcation of these clades and for their diagnostics. Based on the results of our comprehensive phylogenomic analyses and numerous identified molecular signatures, which consistently and strongly support the division of known mycobacterial species into the five

Phylogenomics and Comparative Genomic Studies Robustly Support Division of the Genus Mycobacterium into an Emended Genus Mycobacterium and Four Novel Genera

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Radhey S. Gupta

2018-02-01

Full Text Available The genus Mycobacterium contains 188 species including several major human pathogens as well as numerous other environmental species. We report here comprehensive phylogenomics and comparative genomic analyses on 150 genomes of Mycobacterium species to understand their interrelationships. Phylogenetic trees were constructed for the 150 species based on 1941 core proteins for the genus Mycobacterium, 136 core proteins for the phylum Actinobacteria and 8 other conserved proteins. Additionally, the overall genome similarity amongst the Mycobacterium species was determined based on average amino acid identity of the conserved protein families. The results from these analyses consistently support the existence of five distinct monophyletic groups within the genus Mycobacterium at the highest level, which are designated as the “Tuberculosis-Simiae,” “Terrae,” “Triviale,” “Fortuitum-Vaccae,” and “Abscessus-Chelonae” clades. Some of these clades have also been observed in earlier phylogenetic studies. Of these clades, the “Abscessus-Chelonae” clade forms the deepest branching lineage and does not form a monophyletic grouping with the “Fortuitum-Vaccae” clade of fast-growing species. In parallel, our comparative analyses of proteins from mycobacterial genomes have identified 172 molecular signatures in the form of conserved signature indels and conserved signature proteins, which are uniquely shared by either all Mycobacterium species or by members of the five identified clades. The identified molecular signatures (or synapomorphies provide strong independent evidence for the monophyly of the genus Mycobacterium and the five described clades and they provide reliable means for the demarcation of these clades and for their diagnostics. Based on the results of our comprehensive phylogenomic analyses and numerous identified molecular signatures, which consistently and strongly support the division of known mycobacterial species

[Immunochemical Detection of Azospirilla in Soil with Genus-Specific Antibodies].

Science.gov (United States)

Shirokov, A A; Krasov, A I; Selivanov, N Yu; Burygin, G L; Shchegolev, S Yu; Matora, L Yu

2015-01-01

Immunoelectrophoresis and immunodiffusion analysis with antibodies to whole intact cells of the type strain of nitrogen-fixing soil bacteria Azospirillum brasilense Sp7 revealed at least three conservative surface immunogenic proteins of azospirilla. Cross-reactions with these proteins made it possible to use the above antibodies for detection of azospirilla as a genus-specific probe conjugated with horseradish peroxidase as an enzymatic label. Direct immune-enzyme analysis of soil suspensions (typical chernozem, Saratov oblast) confirmed applicability of the conjugates based on genus-specific antibodies to the surface proteins of azospirilla for direct detection of this bacterial genus in environmental samples. These results provide a basis for broad application of this method for analysis of Azospirillum occurrence in soil.

Notes on the genus Paramignya: Phytochemistry and biological activity

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Ninh The Son

2018-06-01

Full Text Available Genus Paramignya belongs to Rutaceae family, with interesting secondary metabolites, comprising main classes of compounds coumarin and coumarin glycosides, acridone alkaloids, tirucallane and tirucallane glycosides, phenols, and flavonoids, as well as several compounds limonoid, lignin glycoside and sterol. Paramignya species has been employing as folk medicines against hepatitis, diabetes, cancer, nose infections. Many bioactive reported such as cytotoxic assay, antioxidant, antiinflammatory, antiumor cancer, α-glucosidase inhibitory activities indicated either Paramignya extracts, fractions, or isolated compounds to become valuable resources for natural new drug developments. However, no evidences are reported for general view about this genus. In current paper, we exhibit overview almost of isolated components and biological evaluations from this genus. These findings are important to improve the values of these medicinal plants for the health benefit, drug discovery and guideline for future researches.

Torsionfree Sheaves over a Nodal Curve of Arithmetic Genus One

Indian Academy of Sciences (India)

We classify all isomorphism classes of stable torsionfree sheaves on an irreducible nodal curve of arithmetic genus one defined over C C . Let be a nodal curve of arithmetic genus one defined over R R , with exactly one node, such that does not have any real points apart from the node. We classify all isomorphism ...

Evidence for Ecological Flexibility in the Cosmopolitan Genus Curtobacterium

OpenAIRE

Chase, Alexander B.; Arevalo, Philip; Polz, Martin F.; Berlemont, Renaud; Martiny, Jennifer B. H.

2016-01-01

Assigning ecological roles to bacterial taxa remains imperative to understanding how microbial communities will respond to changing environmental conditions. Here we analyze the genus Curtobacterium as it was found to be the most abundant taxon in a leaf litter community in southern California. Traditional characterization of this taxon predominantly associates it as the causal pathogen in the agricultural crops of dry beans. Therefore, we seek to conduct a broad investigation into this genus...

A taxonomic monograph of the leaf-litter inhabiting weevil genus Plumolepilius new genus (Coleoptera: Curculionidae: Molytinae: Conotrachelini) from Mexico, Guatemala, and El Salvador.

Science.gov (United States)

Barrios-Izás, Manuel A; Anderson, Robert S; Morrone, Juan J

2016-09-14

We describe the Mesoamerican leaf litter weevil genus Plumolepilius Barrios-Izás & Anderson, new genus (Coleoptera: Curculionidae: Molytinae: Conotrachelini) (type species P. trifiniensis Barrios-Izás & Anderson, new species), species of which inhabit mountain ecosystems from the state of Chiapas in southeastern Mexico to northern Panama. In this paper we describe nine new species from Mexico, Guatemala, and El Salvador: P. trifiniensis Barrios-Izás & Anderson, new species (El Salvador and Guatemala); P. branstetteri Barrios-Izás & Anderson, new species (Guatemala and Mexico); P. longinoi Barrios-Izás & Anderson, new species (Guatemala and Mexico); P. cortezi Barrios-Izás & Anderson, new species (Guatemala and Mexico); P. canoi Barrios-Izás & Anderson, new species (Guatemala); P. schusteri Barrios-Izás & Anderson, new species (Guatemala and Mexico); P. daryi Barrios-Izás & Anderson, new species (Guatemala); P. yolnabajensis Barrios-Izás & Anderson, new species (Guatemala); and P. macalajauensis Barrios-Izás & Anderson, new species (Guatemala).        The genus and the species are named and described, information on their geographical distributions is given and images of the habitus of both sexes and the aedeagus are presented. A key to the species of Plumolepilius based on males is included.        The monophyly of Plumolepilius was confirmed by a parsimony analysis of external and male aedeagus morphology and the genus is best characterized by the presence of plumose scales lining the prosternal channel. Phylogenetic analysis supports that Lepilius Champion 1905 is the sister genus of Plumolepilius.

Bildskapande i relation till genus i förskolans verksamhet : Att skapa sig själv och genus

OpenAIRE

Brännlund, Angelika

2018-01-01

Studiens syfte är att bidra till ökad medvetenhet för verksamma inom förskolans område kring frågor som rör pedagogers förhållningssätt kring relationen mellan bildskapande och genus, men även hur dessa förhållningssätt kan påverka barnens möjligheter i deras bildskapande. En viktig fråga som burits med från starten av arbetet och som lyser igenom i resultatdelen har varit: Vilka möjligheter att förhålla sig till bildskapande och genus kan uppstå om ett kritiskt sätt att tänka kring könsstere...

Proteomic Analysis of Stationary Phase in the Marine Bacterium "Candidatus Pelagibacter ubique"

Energy Technology Data Exchange (ETDEWEB)

Sowell, S. M.; Norbeck, A. D.; Lipton, M. S.; Nicora, C. D.; Callister, S. J.; Smith, R. D.; Barofsky, D. F.; Giovannoni, S. J.

2008-05-09

The α-proteobacterium ‘Candidatus Pelagibacter ubique’ str. HTCC1062, and most other members of the SAR11 clade, lack genes for assimilatory sulfate reduction, making them dependent on organosulfur compounds that occur naturally in seawater. To investigate how these cells adapt to sulfur limitation, batch cultures were grown in defined media containing either limiting or non-limiting amounts of dimethylsulfoniopropionate (DMSP) as the sole sulfur source. Protein and mRNA expression were measured during exponential growth, immediately prior to stationary phase, and in late stationary phase. Two distinct responses were observed: one as DMSP became exhausted, and another as cells acclimated to a sulfur-limited environment. The first response was characterized by increased transcription and translation of all Ca. P. ubique genes downstream of previously confirmed S-adenosyl methionine (SAM) riboswitches: bhmT, mmuM, and metY. Proteins encoded by these genes were up to 33 times more abundant as DMSP became limiting. Their predicted function is to shunt all available sulfur to methionine. The secondary response, observed during sulfur-depleted stationary phase, was a 6-10 fold increase in transcription of the heme c shuttle ccmC and two small genes of unknown function (SAR11_1163 and SAR11_1164). This bacterium's strategy for coping with sulfur stress appears to be intracellular redistribution to support methionine biosynthesis, rather than increasing organosulfur import. Many of the genes and SAM riboswitches involved in this response are located in a hypervariable genome region (HVR). One of these HVR genes, ordL, is located downstream of a conserved motif that evidence suggests is a novel riboswitch.

Ecological Distribution Of The Genus Crotalaria In Nigeria

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Odewo

2015-08-01

Full Text Available Abstract Geographical distribution and morphological features of the genus Crotalaria were studied. Methods follow conventional practice as reported by previous studies. Thirty six species of the genus Crotalaria were shown to be distributed in Nigeria. The genera were allopathic in nature. The species such as C. bongensis C. atrorubens C. cleomifolia C. anthyllopsis C. cuspidata C. bamendul C. calycina C. hyssopifolia C. incana C. graminicola and C. macrocalyx were prominent in savannah zones while C. acervata C. cylindrical C. cephalotes C. comosa C. retusa C.doniana C. glauca C. falcata C. goreensis among others were common in cultivated areas in forest zone of Nigeria. Qualitative leaf morphological features of selected crotalaria species in Nigeria were also revealed. It shows that the leaf margin leaf surface and leaf base are similar in features except in leaf shape that vary from lanceolate C. comosa and C. bongensis oblanceolate C. retusa C. goreensis C. ononoidea and C. lachnosema to obovate C. mucronata and C. naragutensis. This implies that most of the genus Crotalaria displays similar characteristic and the features among them shows overlap.

Review of the Genus Apechthis (Hymenoptera: Ichneumonidae: Pimplinae from South Korea

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Choi, Jin-Kyung

2015-04-01

Full Text Available We reviewed South Korean species of the genus Apechthis and confirmed four species and two subspecies. In this genus, four species and one subspecies have been reported from the Eastern Palaearctic region, two species and one subspecies were from South Korea. Additionally, we report two species and one subspecies, Apechthis compunctor orientalis Kaspryan, 1973, Apechthis quadridentata (Thomson, 1877 and Apechthis rapae (Uchida, 1925, which were newly recorded for the first time from South Korea. A key to South Korean species of the genus Apechthis, redescriptions of newly recorded species and subspecies and digital images of South Korean Apechthis are provided.

Biodegradation of chlorpyrifos by bacterial genus Pseudomonas.

Science.gov (United States)

Gilani, Razia Alam; Rafique, Mazhar; Rehman, Abdul; Munis, Muhammad Farooq Hussain; Rehman, Shafiq Ur; Chaudhary, Hassan Javed

2016-02-01

Chlorpyrifos is an organophosphorus pesticide commonly used in agriculture. It is noxious to a variety of organisms that include living soil biota along with beneficial arthropods, fish, birds, humans, animals, and plants. Exposure to chlorpyrifos may cause detrimental effects as delayed seedling emergence, fruit deformities, and abnormal cell division. Contamination of chlorpyrifos has been found about 24 km from the site of its application. There are many physico-chemical and biological approaches to remove organophosphorus pesticides from the ecosystem, among them most promising is biodegradation. The 3,5,6-trichloro-2-pyridinol (TCP) and diethylthiophosphate (DETP) as primary products are made when chlorpyrifos is degraded by soil microorganisms which further break into nontoxic metabolites as CO(2), H(2)O, and NH(3). Pseudomonas is a diversified genus possessing a series of catabolic pathways and enzymes involved in pesticide degradation. Pseudomonas putida MAS-1 is reported to be more efficient in chlorpyrifos degradation by a rate of 90% in 24 h among Pseudomonas genus. The current review analyzed the comparative potential of bacterial species in Pseudomonas genus for degradation of chlorpyrifos thus, expressing an ecofriendly approach for the treatment of environmental contaminants like pesticides. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Medicinal uses, phytochemistry and pharmacology of the genus Uncaria.

Science.gov (United States)

Zhang, Qian; Zhao, Jiao Jiao; Xu, Jian; Feng, Feng; Qu, Wei

2015-09-15

The genus Uncaria belongs to the family Rubiaceae, which mainly distributed in tropical regions, such as Southeast Asia, Africa and Southeast America. Their leaves and hooks have long been thought to have healing powers and are already being tested as a treatment for asthma, cancer, cirrhosis, diabetes, hypertension, stroke and rheumatism. The present review aims to provide systematically reorganized information on the ethnopharmacology, phytochemistry and pharmacology of the genus Uncaria to support for further therapeutic potential of this genus. To better understanding this genus, information on the stereo-chemistry and structure-activity relationships in indole alkaloids is also represented. The literature study of this review is based on various databases search (SCIFinder, Science Direct, CNKI, Wiley online library, Spring Link, Web of Science, PubMed, Wanfang Data, Medalink, Google scholar, ACS, Tropicos, Council of Heads of Australasian Herbaria, The New York Botanical Garden, African Plants Database at Genera Botanical Garden, The Plant List and SEINet) and library search for Biological Abstract and some local books on ethnopharmacology. 19 species of the genus Uncaria are found to be important folk medicines in China, Malaysia, Phillippines, Africa and Southeast America, etc, and have been served for the treatment of asthma, rheumatism, hyperpyrexia, hypertension and headaches, etc. More than 200 compounds have been isolated from Uncaria, including indole alkaloids, triterpenes, flavonoids, phenols, phenylpropanoids, etc. As characteristic constituents, indole alkaloids have been considered as main efficacy component for hypertension, epilepsy, depressant, Parkinson's disease and Alzheimer's disease. In addition, pharmacokinetic and metabolism investigation reveal that the indole alkaloids are likely to be absorbed, metabolized and excreted at early time points. Moreover, the specific inhibition of CYP isozymes can regulate their hydroxylation metabolites

Polyphasic taxonomy of the genus Talaromyces

DEFF Research Database (Denmark)

Yilmaz, N.; Visagie, C.M.; Houbraken, J.

2014-01-01

The genus Talaromyces was described by Benjamin in 1955 as a sexual state of Penicillium that produces soft walled ascomata covered with interwoven hyphae. Phylogenetic information revealed that Penicillium subgenus Biverticillium and Talaromyces form a monophyletic clade distinct from the other...

A new genus of Rhytirrhinini from Colombia (Coleoptera: Curculionidae)

OpenAIRE

Morrone Juan J.

1995-01-01

Rupanius, new genus, comprises the single species R. carinatus, new species, endemic to the Paramo biogeographic province of Colombia. It is diagnosed based on the elytra subquadrate and with a conspicuous declivital carina, and is considered similar to Puranlus Germain and Acrorius Kirsch. The genus and species are described, illustrated, and compared with the other Colombian Rhytirrhinini.Rupanius, gen. n., comprende la única especie R. carinatus, sp. n., endémica de la provincia biogeográf...

The Polyakov relation for the sphere and higher genus surfaces

International Nuclear Information System (INIS)

Menotti, Pietro

2016-01-01

The Polyakov relation, which in the sphere topology gives the changes of the Liouville action under the variation of the position of the sources, is also related in the case of higher genus to the dependence of the action on the moduli of the surface. We write and prove such a relation for genus 1 and for all hyperelliptic surfaces. (paper)

Molecular phylogeny and systematic revision of the pleurocarpous moss genus Plagiothecium

DEFF Research Database (Denmark)

Wynns, Justin Thomas

A systematic investigation of the pleurocarpous moss genus Plagiothecium Bruch & Schimp. was performed as a part of the author’s PhD study at the University of Copenhagen. Plagiothecium is mostly a well-defined genus, but the species limits and the interspecific relationships are poorly understood...

The genus Cordia: botanists, ethno, chemical and pharmacological aspects

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Edinardo Fagner Ferreira Matias

Full Text Available ABSTRACTSpecies of the genus Cordia, Boraginaceae, are widely studied with regard to the various ethnobotanical and ethnopharmacological aspects. They are found principally in tropical and subtropical regions of the American, Asian and African continents, where they occur in various countries. In the genus Cordia, there are many species cultivated for ornamental plants, wood and medicinal applications, where they are extensively utilized by traditional communities. In the last decades, scientific studies of Cordia species have intensified, demonstrating the great interest in phytochemical, biological and pharmacological studies. In this review, we describe the principal botanical aspects, ethnopharmacological information and evaluation of the bioactive and pharmacological properties of Cordia, its phytochemical constituents and the most common classes of secondary metabolites identified. The information reported in this work contributes scientifically to recognizing the importance of the genus Cordia as a target in the search for new biotechnological investments.

Genetic variability assessment in the genus Passiflora by SSR markers

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Claudia Lougon Paiva

2014-09-01

Full Text Available The genus Passiflora encompasses many species that are endemic to the Brazilian territory, including some with economic value. Studies on genetic diversity in this genus are fundamental because they allow understanding genetic variability and distance. The present study aimed to determine the genetic variability and distances among 10 species of the genus Passiflora by using microsatellite markers (Simple Sequence Repeat, SSR. Twenty-eight heterologous microsatellite markers were tested, but only 12 were used in the diversity analysis because they amplified in at least 80% of the species. A clear separation was observed among the subgenuses studied, as well as wide variation among the accessions of Passiflora. This knowledge enables breeders to explore diversity and transfer favorable alleles found in wild species.

Protomedetera, a new genus from the Oriental and Australasian realms (Diptera, Dolichopodidae, Medeterinae).

Science.gov (United States)

Tang, Chufei; Grootaert, Patrick; Yang, Ding

2018-01-01

Protomedetera gen. n. (Diptera: Dolichopodidae), a new genus of the subfamily Medeterinae, is described from the Oriental and Australasian realms based on four new species. Protomedetera singaporensis Grootaert & Tang, sp. n. is designated as type of the new genus. The genus is peculiar because of the small body size, the small globular first flagellomere (postpedicel), the simple male genitalia with indistinct or small epandrial lobe and half-hidden cercus. The following four new species are described and illustrated: P. biconvexa sp. n. , P. biseta sp. n. , P. glabra sp. n. , and P. singaporensis sp. n. A key to the species of the new genus is provided.

An updated review on pharmacological activities and phytochemical constituents of evening primrose (genus Oenothera

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Rebecca Munir

2017-11-01

Full Text Available Genus Oenothera includes medicinal plants that are distributed throughout the world and are known since ancient times. Popular indications of different species of this genus include treatment of inflammations, diabetes, microbial infections, ulcers, tumors, kidney and liver problems. The plants of this genus are a botanical source for various pharmaceutically active components like sterols, alkaloids, phenolic acids, flavonoids, triterpenoids, saponins, biflavonols and tocopherols. This review article is a compilation of chemical composition and biological activities of the various species of the genus Oenothera.

Degenerate conformal theories on higher-genus surfaces

International Nuclear Information System (INIS)

Gerasimov, A.A.

1989-01-01

Two-dimensional degenerate field theories on higher-genus surfaces are investigated. Objects are built on the space of moduli, whose linear combinations are hypothetically conformal blocks in degenerate theories

The genus Alterosa Blahnik, 2005 (Trichoptera, Philopotamidae, Philopotaminae) in northeastern Brazil, including the description of three new species and an identification key for the genus

Science.gov (United States)

Dumas, Leandro Lourenço; Calor, Adolfo Ricardo; Nessimian, Jorge Luiz

2013-01-01

Abstract Alterosa Blahnik, 2005 contains 35 described species distributed in southern and southeastern Brazil. Three new species of Alterosa from northeastern Brazil are described and illustrated, Alterosa amadoi sp. n., Alterosa castroalvesi sp. n. and Alterosa caymmii sp. n., the first records of the genus from northeastern Brazil. An identification key for all known species of the genus is also presented. PMID:23950667

In-Depth Transcriptome Sequencing of Mexican Lime Trees Infected with Candidatus Phytoplasma aurantifolia.

Science.gov (United States)

Mardi, Mohsen; Karimi Farsad, Laleh; Gharechahi, Javad; Salekdeh, Ghasem Hosseini

2015-01-01

Witches' broom disease of acid lime greatly affects the production of Mexican lime in Iran. It is caused by a phytoplasma (Candidatus Phytoplasma aurantifolia). However, the molecular mechanisms that underlie phytoplasma pathogenicity and the mode of interactions with host plants are largely unknown. Here, high-throughput transcriptome sequencing was conducted to explore gene expression signatures associated with phytoplasma infection in Mexican lime trees. We assembled 78,185 unique transcript sequences (unigenes) with an average length of 530 nt. Of these, 41,805 (53.4%) were annotated against the NCBI non-redundant (nr) protein database using a BLASTx search (e-value ≤ 1e-5). When the abundances of unigenes in healthy and infected plants were compared, 2,805 transcripts showed significant differences (false discovery rate ≤ 0.001 and log2 ratio ≥ 1.5). These differentially expressed genes (DEGs) were significantly enriched in 43 KEGG metabolic and regulatory pathways. The up-regulated DEGs were mainly categorized into pathways with possible implication in plant-pathogen interaction, including cell wall biogenesis and degradation, sucrose metabolism, secondary metabolism, hormone biosynthesis and signalling, amino acid and lipid metabolism, while down-regulated DEGs were predominantly enriched in ubiquitin proteolysis and oxidative phosphorylation pathways. Our analysis provides novel insight into the molecular pathways that are deregulated during the host-pathogen interaction in Mexican lime trees infected by phytoplasma. The findings can be valuable for unravelling the molecular mechanisms of plant-phytoplasma interactions and can pave the way for engineering lime trees with resistance to witches' broom disease.

The gastropod-symbiotic sea anemone genus Isosicyonis Carlgren, 1927 (Actiniaria: Actiniidae: a new species from the Weddell Sea (Antarctica that clarifies the taxonomic position of the genus

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Estefanía Rodríguez

2008-03-01

Full Text Available A second species of the sea anemone genus Isosicyonis is described and illustrated from 16 specimens collected in the Weddell Sea (Antarctica on the Polarstern cruises ANT XVII/3, ANT XXI/2 and ANT XXIII/8. Isosicyonis striata n. sp. is easily distinguishable externally from the other species of the genus Isosicyonis alba by its pattern: white longitudinal stripes on the column, oral disc, and tentacles. It is also distinguished by internal features including the retractor muscles, parietobasilar muscles, marginal sphincter muscles, number of mesenteries, and cnidae. The genus Isosycionis is currently only known from the Southern Ocean. Both species of Isosicyonis live in association with a gastropod, with a single sea anemone occupying almost the whole shell of its gastropod host. The description of this new species, and our re-examination of Isosicyonis alba, resolves the controversial higher taxonomic position of the genus, confirming its placement within the Endomyaria.

Notes on the taxonomic position of several species of the genus Diphascon (Tardigrada, Hypsibiidae).

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Tumanov, Denis V

2018-03-20

For this paper I analysed the descriptions of all species, attributed to the genus Diphascon Plate, 1889, to ascertain if they fit the diagnosis of this genus, provided by Bertolani et al. 2014. Thirty four species (the majority of the species diversity classified within the genus) fully match its emended diagnosis, while three: Diphascon opisthoglyptum Maucci, 1987, Diphascon procerum Pilato, Sabella Lisi, 2014 and Diphascon ziliense Lisi, Sabella Pilato, 2014, demonstrate a combination of characters, typical to the genus Pilatobius Bertolani et al., 2014. I propose the transfer these three species to the genus Pilatobius, thus their new taxonomic positions are as follows: Pilatobius opisthoglyptus (Maucci, 1987) comb. nov., Pilatobius procerus (Pilato, Sabella Lisi, 2014) comb. nov. and Pilatobius ziliense (Lisi, Sabella Pilato, 2014) comb. nov. Descriptions of three other Diphascon species (Diphascon mariae (Mihelčič, 1951), Diphascon rivulare (Mihelčič, 1967) and Diphascon punctatum (Iharos, 1962)) contain too little detail to conclude on their taxonomic position. The species Pilatobius halapiense (Iharos, 1964) was erroneously transferred from the genus Diphascon, and here I suggest it is transferred back to Diphascon. The new taxonomic position of this species is: Diphascon halapiense (Iharos, 1964) comb. nov. Emended list of species, attributed to the genus Diphascon is given.

The genus Scrophularia: a source of iridoids and terpenoids with a diverse biological activity.

Science.gov (United States)

Pasdaran, Ardalan; Hamedi, Azadeh

2017-12-01

Scrophularia genus (Scrophulariaceae) includes about 350 species commonly known as figwort. Many species of this genus grow wild in nature and have not been cultivated yet. However, some species are in danger of extinction. This paper reviews the chemical compounds, biological activities and the ethnopharmacology of some Scrophularia species. All information was obtained through reported data on bibliographic database such as Scopus, United States National Agricultural Library, Biological Abstracts, EMBASE, PubMed, MedlinePlus, PubChem and Springer Link (1934-2017). The information in different Pharmacopoeias on this genus was also gathered from 1957 to 2007. The structures of 204 compounds and their biological activity were presented in the manuscript: glycoside esters, iridoid glycosides and triterpenoids are the most common compounds in this genus. Among them, scropolioside like iridoids have shown potential for anti-inflammatory, hepatoprotective and wound healing activity. Among the less frequently isolated compounds, resin glycosides such as crypthophilic acids have shown potent antiprotozoal and antimicrobial activities. The Scrophularia genus seems to be a rich source of iridoids and terpenoids, but isolation and identification of its alkaloids have been a neglected area of scientific study. The diverse chemical compounds and biological activities of this genus will motivate further investigation on Scrophularia genus as a source of new therapeutic medications.

Localization and dynamics of Wolbachia infection in Asian citrus psyllid Diaphorina citri, the insect vector of the causal pathogens of Huanglongbing.

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Ren, Su-Li; Li, Yi-Han; Ou, Da; Guo, Yan-Jun; Qureshi, Jawwad A; Stansly, Philip A; Qiu, Bao-Li

2018-03-23

Wolbachia is a group of intracellular bacteria that infect a wide range of arthropods including the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama. This insect is the vector of Candidatus Liberibacter asiaticus (CLas), the causal pathogen of Huanglongbing or citrus greening disease. Here, we investigated the localization pattern and infection dynamics of Wolbachia in different developmental stages of ACP. Results revealed that all developmental stages of ACP including egg, 1st-5th instar nymphs, and adults of both gender were infected with Wolbachia. FISH visualization of an ACP egg showed that Wolbachia moved from the egg stalk of newly laid eggs to a randomly distributed pattern throughout the egg prior to hatching. The infection rate varied between nymphal instars. The titers of Wolbachia in fourth and fifth instar nymphs were significantly higher than those in the first and second instar nymphs. Wolbachia were scattered in all nymphal stages, but with highest intensity in the U-shaped bacteriome located in the abdomen of the nymph. Wolbachia was confined to two symmetrical organizations in the abdomen of newly emerged female and male adults. The potential mechanisms of Wolbachia infection dynamics are discussed. © 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

The genetic structure of an invasive pest, the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae).

Science.gov (United States)

Guidolin, Aline S; Fresia, Pablo; Cônsoli, Fernando L

2014-01-01

The Asian citrus psyllid Diaphorina citri is currently the major threat to the citrus industry as it is the vector of Candidatus Liberibacter, the causal agent of huanglongbing disease (HLB). D. citri is native to Asia and now colonizes the Americas. Although it has been known in some countries for a long time, invasion routes remain undetermined. There are no efficient control methods for the HLB despite the intensive management tools currently in use. We investigated the genetic variability and structure of populations of D. citri to aid in the decision making processes toward sustainable management of this species/disease. We employed different methods to quantify and compare the genetic diversity and structure of D. citri populations among 36 localities in Brazil, using an almost complete sequence of the cytochrome oxidase I (COI) gene. Our analyses led to the identification of two geographically and genetically structured groups. The indices of molecular diversity pointed to a recent population expansion, and we discuss the role of multiple invasion events in this scenario. We also argue that such genetic diversity and population structure may have implications for the best management strategies to be adopted for controlling this psyllid and/or the disease it vectors in Brazil.

GENETIC Diaphorina citri DIVERSITY ON CITRUS CROPS OF THE VALLE DEL CAUCA AND QUINDÍO (COLOMBIA

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MIGUEL ANGEL MONCAYO-DONOSO

2014-07-01

Full Text Available The Asiatic psyllid Diaphorina citri (Hemiptera: Psyllidae is the main vector of Candidatus liberibacter, which causes the Huanglongbing HLB disease, known for devastating citrus in the world but not yet reported in Colombia. The genetic variability of the D. citri population was studied through sequencing the COI mitochondrial gene as molecular marker. Adults were collected in citrus producing zones of the Colombian Valle del Cauca and Quindío. Amplification was performed with two pairs of specific primers for Hemiptera. The PCR products were sequenced at Macrogen-Korea, obtaining a total of 124 sequences. For the bioinformatic analysis, the Vector NTI 11.5, Harlequin V 3.5, MEGA 5 and MAFFT 6 programs were used. The molecular diversity indices between populations were similar, revealing a common origin and a recent split of the populations excluding a significant genetic differentiation associated to variations of the bacterium, however the haplotype diversity index was higher than the nucleotide diversity index. The latter one showed a low number of polymorphic sites, indicating that the D. citri populations are expanding. The study of the vector’s genetic variability is a tool for the prediction of likely scenarios for the spread of diseases.

The genetic structure of an invasive pest, the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae.

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Aline S Guidolin

Full Text Available The Asian citrus psyllid Diaphorina citri is currently the major threat to the citrus industry as it is the vector of Candidatus Liberibacter, the causal agent of huanglongbing disease (HLB. D. citri is native to Asia and now colonizes the Americas. Although it has been known in some countries for a long time, invasion routes remain undetermined. There are no efficient control methods for the HLB despite the intensive management tools currently in use. We investigated the genetic variability and structure of populations of D. citri to aid in the decision making processes toward sustainable management of this species/disease. We employed different methods to quantify and compare the genetic diversity and structure of D. citri populations among 36 localities in Brazil, using an almost complete sequence of the cytochrome oxidase I (COI gene. Our analyses led to the identification of two geographically and genetically structured groups. The indices of molecular diversity pointed to a recent population expansion, and we discuss the role of multiple invasion events in this scenario. We also argue that such genetic diversity and population structure may have implications for the best management strategies to be adopted for controlling this psyllid and/or the disease it vectors in Brazil.

Analyses of Mitogenome Sequences Revealed that Asian Citrus Psyllids (Diaphorina citri) from California Were Related to Those from Florida.

Science.gov (United States)

Wu, Fengnian; Kumagai, Luci; Cen, Yijing; Chen, Jianchi; Wallis, Christopher M; Polek, MaryLou; Jiang, Hongyan; Zheng, Zheng; Liang, Guangwen; Deng, Xiaoling

2017-08-31

Asian citrus psyllid (ACP, Diaphorina citri Kuwayama) transmits "Candidatus Liberibacter asiaticus" (CLas), an unculturable alpha-proteobacterium associated with citrus Huanglongbing (HLB). CLas has recently been found in California. Understanding ACP population diversity is necessary for HLB regulatory practices aimed at reducing CLas spread. In this study, two circular ACP mitogenome sequences from California (mt-CApsy, ~15,027 bp) and Florida (mt-FLpsy, ~15,012 bp), USA, were acquired. Each mitogenome contained 13 protein coding genes, 2 ribosomal RNA and 22 transfer RNA genes, and a control region varying in sizes. The Californian mt-CApsy was identical to the Floridian mt-FLpsy, but different from the mitogenome (mt-GDpsy) of Guangdong, China, in 50 single nucleotide polymorphisms (SNPs). Further analyses were performed on sequences in cox1 and trnAsn regions with 100 ACPs, SNPs in nad1-nad4-nad5 locus through PCR with 252 ACP samples. All results showed the presence of a Chinese ACP cluster (CAC) and an American ACP cluster (AAC). We proposed that ACP in California was likely not introduced from China based on our current ACP collection but somewhere in America. However, more studies with ACP samples from around the world are needed. ACP mitogenome sequence analyses will facilitate ACP population research.

Odorants for surveillance and control of the Asian Citrus Psyllid (Diaphorina citri.

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Iliano V Coutinho-Abreu

Full Text Available The Asian Citrus Psyllid (ACP, Diaphorina citri, can transmit the bacterium Candidatus Liberibacter while feeding on citrus flush shoots. This bacterium causes Huanglongbing (HLB, a major disease of citrus cultivation worldwide necessitating the development of new tools for ACP surveillance and control. The olfactory system of ACP is sensitive to variety of odorants released by citrus plants and offers an opportunity to develop new attractants and repellents.In this study, we performed single-unit electrophysiology to identify odorants that are strong activators, inhibitors, and prolonged activators of ACP odorant receptor neurons (ORNs. We identified a suite of odorants that activated the ORNs with high specificity and sensitivity, which may be useful in eliciting behavior such as attraction. In separate experiments, we also identified odorants that evoked prolonged ORN responses and antagonistic odorants able to suppress neuronal responses to activators, both of which can be useful in lowering attraction to hosts. In field trials, we tested the electrophysiologically identified activating odorants and identified a 3-odor blend that enhances trap catches by ∼230%.These findings provide a set of odorants that can be used to develop affordable and safe odor-based surveillance and masking strategies for this dangerous pest insect.

Plant pathogen-induced volatiles attract parasitoids to increase parasitism of an insect vector

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Xavier eMartini

2014-05-01

Full Text Available Interactions between plant pathogens and arthropods have been predominantly studied through the prism of herbivorous arthropods. Currently, little is known about the effect of plant pathogens on the third trophic level. This question is particularly interesting in cases where pathogens manipulate host phenotype to increase vector attraction and presumably increase their own proliferation. Indeed, a predator or a parasitoid of a vector may take advantage of this manipulated phenotype to increase its foraging performance. We explored the case of a bacterial pathogen, Candidatus Liberibacter asiaticus (Las, which modifies the odors released by its host plant (citrus trees to attract its vector, the psyllid Diaphorina citri. We found that the specialist parasitoid of D. citri, Tamarixia radiata, was attracted more toward Las-infected than uninfected plants. We demonstrated that this attractiveness was due to the release of methyl salicylate. Parasitization of D. citri nymphs on Las-infected plants was higher than on uninfected controls. Also, parasitization was higher on uninfected plants baited with methyl salicylate than on non-baited controls. This is the first report of a parasitoid ‘eavesdropping’ on a plant volatile induced by bacterial pathogen infection, which also increases effectiveness of host seeking behavior of its herbivorous vector.

Costs and benefits of insecticide and foliar nutrient applications to huanglongbing-infected citrus trees.

Science.gov (United States)

Tansey, James A; Vanaclocha, Pilar; Monzo, Cesar; Jones, Moneen; Stansly, Philip A

2017-05-01

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), vectors Candidatus Liberibacter asiaticus, which causes huanglongbing (HLB). In Florida, HLB incidence is approaching 100% statewide. Yields have decreased and production costs have increased since 2005. Despite this, some growers are maintaining a level of production and attribute this in part to aggressive psyllid control and foliar nutrition sprays. However, the value of these practices is debated. A replicated field study was initiated in 2008 in a commercial block of 'Valencia' sweet orange trees to evaluate individual and combined effects of foliar nutrition and ACP control. Results from 2012-2016 are presented. Insecticides consistently reduced ACP populations. However, neither insecticide nor nutrition applications significantly influenced HLB incidence or PCR copy number in mature trees. In reset trees, infection continued to build and reached 100% in all treatments. Greatest yields (kg fruit ha -1 ) and production (kg solids ha -1 ) were obtained from trees receiving both insecticides and foliar nutrition. All treatments resulted in production and financial gains relative to controls. However, material and application costs associated with the nutrition component offset these gains, resulting in lesser benefits than insecticides applied alone. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

SO(N) WZNW models on higher-genus Riemann surfaces

International Nuclear Information System (INIS)

Alimohammadi, M.; Arfaei, H.; Bonn Univ.

1993-08-01

With the help of the string functions and fusion rules of SO(2N) 1 , we show that the results on SU(N) 1 correlators on higher-genus Riemann surfaces (HGRS) can be extended to the SO(2N) 1 and other level-one simply-laced WZNW models. Using modular invariance and factorization properties of Green functions we find multipoint correlators of primary and descendant fields of SO(2N+1) 1 WZNW models on higher genus Riemann surfaces. (orig.)

Dimers and the Critical Ising Model on lattices of genus >1

International Nuclear Information System (INIS)

Costa-Santos, Ruben; McCoy, B.M.

2002-01-01

We study the partition function of both Close-Packed Dimers and the Critical Ising Model on a square lattice embedded on a genus two surface. Using numerical and analytical methods we show that the determinants of the Kasteleyn adjacency matrices have a dependence on the boundary conditions that, for large lattice size, can be expressed in terms of genus two theta functions. The period matrix characterizing the continuum limit of the lattice is computed using a discrete holomorphic structure. These results relate in a direct way the lattice combinatorics with conformal field theory, providing new insight to the lattice regularization of conformal field theories on higher genus Riemann surfaces

Genomic characterization of the Taylorella genus.

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Laurent Hébert

Full Text Available The Taylorella genus comprises two species: Taylorella equigenitalis, which causes contagious equine metritis, and Taylorella asinigenitalis, a closely-related species mainly found in donkeys. We herein report on the first genome sequence of T. asinigenitalis, analyzing and comparing it with the recently-sequenced T. equigenitalis genome. The T. asinigenitalis genome contains a single circular chromosome of 1,638,559 bp with a 38.3% GC content and 1,534 coding sequences (CDS. While 212 CDSs were T. asinigenitalis-specific, 1,322 had orthologs in T. equigenitalis. Two hundred and thirty-four T. equigenitalis CDSs had no orthologs in T. asinigenitalis. Analysis of the basic nutrition metabolism of both Taylorella species showed that malate, glutamate and alpha-ketoglutarate may be their main carbon and energy sources. For both species, we identified four different secretion systems and several proteins potentially involved in binding and colonization of host cells, suggesting a strong potential for interaction with their host. T. equigenitalis seems better-equipped than T. asinigenitalis in terms of virulence since we identified numerous proteins potentially involved in pathogenicity, including hemagluttinin-related proteins, a type IV secretion system, TonB-dependent lactoferrin and transferrin receptors, and YadA and Hep_Hag domains containing proteins. This is the first molecular characterization of Taylorella genus members, and the first molecular identification of factors potentially involved in T. asinigenitalis and T. equigenitalis pathogenicity and host colonization. This study facilitates a genetic understanding of growth phenotypes, animal host preference and pathogenic capacity, paving the way for future functional investigations into this largely unknown genus.

Arrasia rostrata (Basidiomycota), a new corticioid genus and species from Italy

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Annarosa Bernicchia; Sergio P. Gorj& #243; n; Karen K. Nakasone

2011-01-01

An unusual corticioid species with distinctive large basidiospores that develop a distal refractive rostrum when fully mature is described as new. It grows on living bark of Juniperus phoenicea on the Italian island of Sardinia. Because it is morphologically distinct from any known genus of corticioid fungi, the new genus Arrasia...

Candidatus Nitrosocaldus cavascurensis, an Ammonia Oxidizing, Extremely Thermophilic Archaeon with a Highly Mobile Genome.

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Abby, Sophie S; Melcher, Michael; Kerou, Melina; Krupovic, Mart; Stieglmeier, Michaela; Rossel, Claudia; Pfeifer, Kevin; Schleper, Christa

2018-01-01

Ammonia oxidizing archaea (AOA) of the phylum Thaumarchaeota are widespread in moderate environments but their occurrence and activity has also been demonstrated in hot springs. Here we present the first enrichment of a thermophilic representative with a sequenced genome, which facilitates the search for adaptive strategies and for traits that shape the evolution of Thaumarchaeota. Candidatus Nitrosocaldus cavascurensis has been enriched from a hot spring in Ischia, Italy. It grows optimally at 68°C under chemolithoautotrophic conditions on ammonia or urea converting ammonia stoichiometrically into nitrite with a generation time of approximately 23 h. Phylogenetic analyses based on ribosomal proteins place the organism as a sister group to all known mesophilic AOA. The 1.58 Mb genome of Ca. N. cavascurensis harbors an amo AXCB gene cluster encoding ammonia monooxygenase and genes for a 3-hydroxypropionate/4-hydroxybutyrate pathway for autotrophic carbon fixation, but also genes that indicate potential alternative energy metabolisms. Although a bona fide gene for nitrite reductase is missing, the organism is sensitive to NO-scavenging, underlining the potential importance of this compound for AOA metabolism. Ca. N. cavascurensis is distinct from all other AOA in its gene repertoire for replication, cell division and repair. Its genome has an impressive array of mobile genetic elements and other recently acquired gene sets, including conjugative systems, a provirus, transposons and cell appendages. Some of these elements indicate recent exchange with the environment, whereas others seem to have been domesticated and might convey crucial metabolic traits.

The Kitaev honeycomb model on surfaces of genus g ≥ 2

Science.gov (United States)

Brennan, John; Vala, Jiří

2018-05-01

We present a construction of the Kitaev honeycomb lattice model on an arbitrary higher genus surface. We first generalize the exact solution of the model based on the Jordan–Wigner fermionization to a surface with genus g = 2, and then use this as a basic module to extend the solution to lattices of arbitrary genus. We demonstrate our method by calculating the ground states of the model in both the Abelian doubled {Z}}}2 phase and the non-Abelian Ising topological phase on lattices with the genus up to g = 6. We verify the expected ground state degeneracy of the system in both topological phases and further illuminate the role of fermionic parity in the Abelian phase.

Phylogenetic placement and taxonomy of the genus Hederorkis (Orchidaceae.

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Joanna Mytnik-Ejsmont

Full Text Available Three plastid regions, matK, rpl32-trnL and rpl16 intron and the ITS1-5.8S-ITS2 nuclear ribosomal DNA were used to demonstrate a phylogenetic placement of the genus Hederorkis (Orchidaceae for the first time. The taxonomic position of this genus has been unclear thus far. The phylogenetic and morphological relations of Hederorkis to the most closely related genera Sirhookera, Adrorhizon, Bromheadia and Polystachya are also discussed. A hypothesis concerning an origin and evolution of Hederorkis is proposed. Hederorkis is an epiphytic two-leaved orchid genus with lateral inflorescence, non-resupinate flowers, elongate gynostemium and rudimentary column foot. It is native to the Indian Ocean Islands. Two species of Hederorkis are recognized worldwide, H. scandens endemic to Mauritius and Réunion and H. seychellensis endemic to Seychelles. For each of the species treated a full synonymy, detailed description and illustration are included. The distribution map and dichotomous keys to the species have also been provided.

Evidence for Ecological Flexibility in the Cosmopolitan Genus Curtobacterium.

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Chase, Alexander B; Arevalo, Philip; Polz, Martin F; Berlemont, Renaud; Martiny, Jennifer B H

2016-01-01

Assigning ecological roles to bacterial taxa remains imperative to understanding how microbial communities will respond to changing environmental conditions. Here we analyze the genus Curtobacterium , as it was found to be the most abundant taxon in a leaf litter community in southern California. Traditional characterization of this taxon predominantly associates it as the causal pathogen in the agricultural crops of dry beans. Therefore, we sought to investigate whether the abundance of this genus was because of its role as a plant pathogen or another ecological role. By collating >24,000 16S rRNA sequences with 120 genomes across the Microbacteriaceae family, we show that Curtobacterium has a global distribution with a predominant presence in soil ecosystems. Moreover, this genus harbors a high diversity of genomic potential for the degradation of carbohydrates, specifically with regards to structural polysaccharides. We conclude that Curtobacterium may be responsible for the degradation of organic matter within litter communities.

Chemotaxonomy of the genus Nuxia (Buddlejaceae)

DEFF Research Database (Denmark)

Jensen, Søren Rosendal

1999-01-01

An investigation of two species of Nuxia (Buddlejaceae) showed that this genus is characterised by the presence of the eight-carbon iridoid glucoside unedoside and/or its derivatives. From N. floribunda was isolated unedoside, nuxioside (6-O-a-L-rhamnopyranosyl-unedoside) and 2''-acetyl-3...

Studies on the Genus Orbitolina (Foraminiferida)

NARCIS (Netherlands)

Hofker, J.

1963-01-01

The genus Orbitolina is described in detail and is shown to be represented by one species only: Orbitolina lenticularis (Blumenbach). This species can be subdivided into form-groups, based on the characteristics of the megalospheric embryonic apparatus. The evolution of the species is orthogenetic.

Stieltjes-Bethe equations in higher genus and branched coverings with even ramifications

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Korotkin, Dmitry

2018-02-01

We describe projective structures on a Riemann surface corresponding to monodromy groups which have trivial SL (2) monodromies around singularities and trivial PSL (2) monodromies along homologically non-trivial loops on a Riemann surface. We propose a natural higher genus analog of Stieltjes-Bethe equations. Links with branched projective structures and with Hurwitz spaces with ramifications of even order are established. We find a higher genus analog of the genus zero Yang-Yang function (the function generating accessory parameters) and describe its similarity and difference with Bergman tau-function on the Hurwitz spaces.

Neocampanella, a new corticioid fungal genus, and a note on Dendrothele bispora

Science.gov (United States)

Karen K. Nakasone; David S. Hibbett; Greta Goranova

2009-01-01

The new genus Neocampanella (Agaricales, Agaricomycetes, Basidiomycota) is established for Dentocorticium btastanos Boidin & Gilles, a crustose species, and the new combination, Neocampanella blastanos, is proposed. Morphological and molecular studies support the recognition of the new genus and its close...

A taxonomic review of the species of the genus Amara Bonelli ...

African Journals Online (AJOL)

The twelve species and subspecies of the pterostichine genus Amara Bonelli living in the study area represent about 22% of the Turkish species of this genus. This study is based on material collected primarily in the province of Kahramanmara, but also in the surrounding provinces of Adana, Adýyaman, Gaziantep, Kayseri ...

AMINOACID COMPOSITION OF SOME SPECIES FROM INULA GENUS

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A. A. Kruglaya

2016-01-01

Full Text Available The majority of medicinal plants and medicinal plant raw materials are understudied pharmacgostically. These plants include species from Inula genus, which range in Russia amounts to up to 40 species. Rhizomes and roots of the Inula helenium L. are broadly applied in scientific and traditional medicine. They have expectorate, styptic, and anti-inflammatory properties.The purpose of the study was to determine the amino-acid composition of some species from Inula genus (Inula germanica, Inula ensifolia, Inula aspera, Inula orientalis, which grow in different regions if the North Caucasus.Methods. The studies were carried out using AAA 400 amino acid analyzer, highly specialized automatized liquid chromatographer with computer management. Aboveground parts of the plants, gathered in mass blossom phase from wild-growing plants and then dried out were the objects of the study.Results. For the first time the amino acid composition and raw protein of some species from Inula genus was determined (Inula germanica, Inula ensifolia, Inula aspera, Inula orientalis, 16 amino acids were discovered, 7 of which were essential, and raw proteins which substantival composition amounted to 16.19% in Inula germanica, 10.78% in Inula ensifolia, Inula aspera (11.15%, Inula orientalis (13.94%.Conclusion. The results of the studies conducted broaden the data about amino acids and protein composition and quantitative content in the species from Inula genus and can be used to develop methods of analysis of the drugs, obtained from these plants.

Landau-Ginzburg Orbifolds, Mirror Symmetry and the Elliptic Genus

OpenAIRE

Berglund, P.; Henningson, M.

1994-01-01

We compute the elliptic genus for arbitrary two dimensional $N=2$ Landau-Ginzburg orbifolds. This is used to search for possible mirror pairs of such models. We show that if two Landau-Ginzburg models are conjugate to each other in a certain sense, then to every orbifold of the first theory corresponds an orbifold of the second theory with the same elliptic genus (up to a sign) and with the roles of the chiral and anti-chiral rings interchanged. These orbifolds thus constitute a possible mirr...

Revision of the genus Endochilus Weise (Coleoptera: Coccinellidae: Chilocorini)

Science.gov (United States)

Łączyński, Piotr; Tomaszewska, Wioletta

2014-01-01

Abstract The members of the endemic African genus EndochilusWeise, 1898 (Coleoptera: Coccinellidae: Chilocorini) are redescribed, diagnosed, and illustrated. Lectotypes are designated for Endochilus compater Weise, Endochilus minor Weise, Endochilus plagiatus Sicard, Endochilus rubicundus Weise, and Endochilus styx Sicard. One new species is described: Endochilus abdominalissp. nov. Notes on the genus and nomenclatural history for each species are provided. A key for iden- tification of all species is presented. Adult characters concerning similarities of Endochilus to other genera of African Chilocorini are discussed. PMID:25373218

SCARDINIUS GENUS IN MOLECULAR STUDIES – A REVIEW

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Ovidiu Popescul

2015-12-01

Full Text Available Scardinius is a genus of ray-finned fish in the Cyprinidae family commonly called rudds. The common rudd(Scardinius erithrophthalmus is a bentho-pelagic freshwater fish that occurs mainly in nutrient-rich, well vegetatedlowland rivers, backwaters, oxbows, ponds and lakes and it is widespread in Europe and middle Asia. It has a mediumlength of 20-30 cm, but it can reach 50 cm. The classification of cyprinids has always been controversial the morphologicaltraits have an unclear homology this led to the idea that the recognized monophyletic groups are surely misinterpreted. Thispaper aims to assess the current level of molecular data regarding Scardinius genera. Some of the molecular data obtainedfor Scardinius genus is from DNA barcoding studies on fresh water fishes, but studies regarding this genus and Cyprinidaefamily used mitochondrial genes like cytochrome b (cyt b and cytochrome oxidase (CO, but nuclear genes or nuclearmicrosatellites were also used. We found that molecular data exists for both nuclear and mitochondrial genes, but this genuswasn’t studied separately and as many of the researchers suggest more taxonomic studies are required in order to solve theuncertainties within it.

Moringa Genus: A Review of Phytochemistry and Pharmacology

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Abd Rani, Nur Zahirah; Husain, Khairana; Kumolosasi, Endang

2018-01-01

Moringa is a genus of medicinal plants that has been used traditionally to cure wounds and various diseases such as colds and diabetes. In addition, the genus is also consumed as a source of nutrients and widely used for purifying water. The genus consists of 13 species that have been widely cultivated throughout Asia and Africa for their multiple uses. The purpose of this review is to provide updated and categorized information on the traditional uses, phytochemistry, biological activities, and toxicological research of Moringa species in order to explore their therapeutic potential and evaluate future research opportunities. The literature reviewed for this paper was obtained from PubMed, ScienceDirect, and Google Scholar journal papers published from 1983 to March 2017. Moringa species are well-known for their antioxidant, anti-inflammatory, anticancer, and antihyperglycemic activities. Most of their biological activity is caused by their high content of flavonoids, glucosides, and glucosinolates. By documenting the traditional uses and biological activities of Moringa species, we hope to support new research on these plants, especially on those species whose biological properties have not been studied to date. PMID:29503616

Phase space and black-hole entropy of higher genus horizons in loop quantum gravity

International Nuclear Information System (INIS)

Kloster, S; Brannlund, J; DeBenedictis, A

2008-01-01

In the context of loop quantum gravity, we construct the phase space of isolated horizons with genus greater than 0. Within the loop quantum gravity framework, these horizons are described by genus g surfaces with N punctures and the dimension of the corresponding phase space is calculated including the genus cycles as degrees of freedom. From this, the black-hole entropy can be calculated by counting the microstates which correspond to a black hole of fixed area. We find that the leading term agrees with the A/4 law and that the sub-leading contribution is modified by the genus cycles

Integrability of Liouville system on high genus Riemann surface: Pt. 1

International Nuclear Information System (INIS)

Chen Yixin; Gao Hongbo

1992-01-01

By using the theory of uniformization of Riemann-surfaces, we study properties of the Liouville equation and its general solution on a Riemann surface of genus g>1. After obtaining Hamiltonian formalism in terms of free fields and calculating classical exchange matrices, we prove the classical integrability of Liouville system on high genus Riemann surface

"Candidatus Fokinia solitaria", a Novel "Stand-Alone" Symbiotic Lineage of Midichloriaceae (Rickettsiales.

Directory of Open Access Journals (Sweden)

Franziska Szokoli

Full Text Available Recently, the family Midichloriaceae has been described within the bacterial order Rickettsiales. It includes a variety of bacterial endosymbionts detected in different metazoan host species belonging to Placozoa, Cnidaria, Arthropoda and Vertebrata. Representatives of Midichloriaceae are also considered possible etiological agents of certain animal diseases. Midichloriaceae have been found also in protists like ciliates and amoebae. The present work describes a new bacterial endosymbiont, "Candidatus Fokinia solitaria", retrieved from three different strains of a novel Paramecium species isolated from a wastewater treatment plant in Rio de Janeiro (Brazil. Symbionts were characterized through the full-cycle rRNA approach: SSU rRNA gene sequencing and fluorescence in situ hybridization (FISH with three species-specific oligonucleotide probes. In electron micrographs, the tiny rod-shaped endosymbionts (1.2 x 0.25-0.35 μm in size were not surrounded by a symbiontophorous vacuole and were located in the peripheral host cytoplasm, stratified in the host cortex in between the trichocysts or just below them. Frequently, they occurred inside autolysosomes. Phylogenetic analyses of Midichloriaceae apparently show different evolutionary pathways within the family. Some genera, such as "Ca. Midichloria" and "Ca. Lariskella", have been retrieved frequently and independently in different hosts and environmental surveys. On the contrary, others, such as Lyticum, "Ca. Anadelfobacter", "Ca. Defluviella" and the presently described "Ca. Fokinia solitaria", have been found only occasionally and associated to specific host species. These last are the only representatives in their own branches thus far. Present data do not allow to infer whether these genera, which we named "stand-alone lineages", are an indication of poorly sampled organisms, thus underrepresented in GenBank, or represent fast evolving, highly adapted evolutionary lineages.

A Rapid Protocol of Crude RNA/DNA Extraction for RT-qPCR Detection and Quantification of 'Candidatus Phytoplasma prunorum'.

Science.gov (United States)

Minguzzi, Stefano; Terlizzi, Federica; Lanzoni, Chiara; Poggi Pollini, Carlo; Ratti, Claudio

2016-01-01

Many efforts have been made to develop a rapid and sensitive method for phytoplasma and virus detection. Taking our cue from previous works, different rapid sample preparation methods have been tested and applied to Candidatus Phytoplasma prunorum ('Ca. P. prunorum') detection by RT-qPCR. A duplex RT-qPCR has been optimized using the crude sap as a template to simultaneously amplify a fragment of 16S rRNA of the pathogen and 18S rRNA of the host plant. The specific plant 18S rRNA internal control allows comparison and relative quantification of samples. A comparison between DNA and RNA contribution to qPCR detection is provided, showing higher contribution of the latter. The method presented here has been validated on more than a hundred samples of apricot, plum and peach trees. Since 2013, this method has been successfully applied to monitor 'Ca. P. prunorum' infections in field and nursery. A triplex RT-qPCR assay has also been optimized to simultaneously detect 'Ca. P. prunorum' and Plum pox virus (PPV) in Prunus.

Baltileuctra gen. nov., a new genus of Leuctridae (Insecta: Plecoptera) in Baltic amber.

Science.gov (United States)

Chen, Zhi-Teng

2018-04-10

A new genus and species of the stonefly family Leuctridae, Baltileuctra foraminis gen. et sp. nov., is described and illustrated based on a well-preserved male specimen from the Eocene Baltic amber. The new genus possesses typical characters of Leuctridae but has diagnostic characters of the thoracic sclerites and terminalia. The relationship between the new genus and other leuctrids is briefly discussed.

The genus Retiboletus in China.

Science.gov (United States)

Zeng, Nian-Kai; Liang, Zhi-Qun; Wu, Gang; Li, Yan-Chun; Yang, Zhu L; Liang, Zhi-Qun

2016-01-01

Species of the genus Retiboletus (Boletaceae, Boletales) in China are investigated based on morphology and phylogenetic analyses of DNA sequences from nuc rDNA internal transcribed spacer (ITS) and partial 28S regions and sequences from the translation elongation factor 1-a gene (tef1a). Six lineages are recovered among the collections studied. Five of these are documented and presented in the present paper, including three new species and two new combinations. The remaining species is not described due to the paucity of material. The specimens from China identified as "R. ornatipes" or "R. retipes" are in fact R. sinensis or R. kauffmanii, those labeled "R. griseus" are either R. fuscus or R. pseudogriseus A key to all known taxa of the genus is provided. Phylogenetic relationships of taxa within Retiboletus are partially resolved. A preliminary biogeographical analysis shows that allied species of Retiboletus between eastern Asia and North/Central America are common but there are no Retiboletus species common to both continents. Species of Retiboletus in Japan and southern China are conspecific or closely related. © 2016 by The Mycological Society of America.

Aerobic Anoxygenic Photosynthesis Is Commonly Present within the Genus Limnohabitans.

Science.gov (United States)

Kasalický, Vojtěch; Zeng, Yonghui; Piwosz, Kasia; Šimek, Karel; Kratochvilová, Hana; Koblížek, Michal

2018-01-01

The genus Limnohabitans ( Comamonadaceae , Betaproteobacteria ) is a common and a highly active component of freshwater bacterioplanktonic communities. To date, the genus has been considered to contain only heterotrophic species. In this study, we detected the photosynthesis genes pufLM and bchY in 28 of 46 strains from three Limnohabitans lineages. The pufM sequences obtained are very closely related to environmental pufM sequences detected in various freshwater habitats, indicating the ubiquity and potential importance of photoheterotrophic Limnohabitans in nature. Additionally, we sequenced and analyzed the genomes of 5 potentially photoheterotrophic Limnohabitans strains, to gain further insights into their phototrophic capacity. The structure of the photosynthesis gene cluster turned out to be highly conserved within the genus Limnohabitans and also among all potentially photosynthetic Betaproteobacteria strains. The expression of photosynthetic complexes was detected in a culture of Limnohabitans planktonicus II-D5 T using spectroscopic and pigment analyses. This was further verified by a novel combination of infrared microscopy and fluorescent in situ hybridization. IMPORTANCE The data presented document that the capacity to perform anoxygenic photosynthesis is common among the members of the genus Limnohabitans , indicating that they may have a novel role in freshwater habitats. Copyright © 2017 American Society for Microbiology.

Generalized regular genus for manifolds with boundary

Directory of Open Access Journals (Sweden)

Paola Cristofori

2003-05-01

Full Text Available We introduce a generalization of the regular genus, a combinatorial invariant of PL manifolds ([10], which is proved to be strictly related, in dimension three, to generalized Heegaard splittings defined in [12].

Large N elliptic genus and AdS/CFT Correspondence

International Nuclear Information System (INIS)

Boer, Jan de

1998-01-01

According to one of Maldacena's dualities, type IIB string theory on AdS 3 x S 3 x K3 is equivalent to a certain N = (4, 4) superconformal field theory. In this note we compute the elliptic genus of the boundary theory in the supergravity approximation. A finite quantity is obtained once we introduce a particular exclusion principle. In the regime where the supergravity approximation is reliable, we find exact agreement with the elliptic genus of a sigma model with target space K3 N /S N

Note on twisted elliptic genus of K3 surface

International Nuclear Information System (INIS)

Eguchi, Tohru; Hikami, Kazuhiro

2011-01-01

We discuss the possibility of Mathieu group M 24 acting as symmetry group on the K3 elliptic genus as proposed recently by Ooguri, Tachikawa and one of the present authors. One way of testing this proposal is to derive the twisted elliptic genera for all conjugacy classes of M 24 so that we can determine the unique decomposition of expansion coefficients of K3 elliptic genus into irreducible representations of M 24 . In this Letter we obtain all the hitherto unknown twisted elliptic genera and find a strong evidence of Mathieu moonshine.

THE GENUS TRIGONOSPORA (THELYPTERIDACEAE IN MALESIA

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RE Holttum

2014-01-01

Full Text Available The distribution of the genus is discussed, and the Malesian species distinguished and described. Two new combinations are effected, Trigono-spora calcarata (Bl. Holtt. and T. koorderSiiH (Chr. Holtt.; the latter is here recognized for the first time as closely related to T. calcarata,.

A study in the genus Vulpia

NARCIS (Netherlands)

Henrard, J.Th.

1937-01-01

In conclusion, we propose the following nomenclatural alterations. For a good classification, the genus Vulpia is to be accepted as a member of the Festuceae. Various names of Vulpia are fixed according to our present rules of nomenclature, viz. V. bromoides (L.) GRAY, V. membranacea (L.) LINK, V.

Biological advances in Bergenia genus plant

African Journals Online (AJOL)

Jane

2011-08-08

Aug 8, 2011 ... Bergenia, a genus belonging to Saxifragaceae family, is one of the most important medicinal plants, has high application values for human. Currently, wild Bergenia is becoming lacking, due to destruction of ecological environment and excessive excavation; furthermore, the study on it is not deep enough,.

Sarawakodendron, a new genus of Celastraceae

NARCIS (Netherlands)

Hou, Ding

1967-01-01

During my trip to Malaysia in 1966, sponsored by the Netherlands Foundation for the Advancement of Tropical Research (WOTRO), for doing field work on Anacardiaceae, a new tree genus was found in Sarawak belonging to the family Celastraceae which I have revised for the Flora Malesiana series I,

The genus Lophopyxis Hook. f. (Lophopyxidaceae)

NARCIS (Netherlands)

Sleumer, H.

1968-01-01

When revising the Icacinaceae from SE. Asia and Malesia recently, my interest was drawn again to the genus Lophopyxis Hook. f. Designated by its author (1887) tentatively as a member of the Euphorbiaceae, it was rejected from this family by Pax as early as 1890. Engler (1893) transferred Lophopyxis

A new genus of Tetratermini (Hymenoptera: Braconidae: Lysiterminae) parasitic on grasshoppers (Gryllacrididae)

NARCIS (Netherlands)

Achterberg, van C.; Steiner, H.

1996-01-01

The new genus Katytermus from Malaysia (type species: Katytermus palmicola spec. nov.) is described and illustrated. The new genus belongs to a new tribe, Tetratermini, of the subfamily Lysiterminae. The type species has been reared as a gregarious endoparasite of a "katydid" longhorn grasshopper

A taxonomic revision of the genus Rafnia Thunb. (Fabaceae, Crotalarieae)

OpenAIRE

2012-01-01

M.Sc. A taxonomic revision of the genus Rafnia Thunb. (= Oedmannia Thunb., Vascoa DC., Pelecynthis E. Mey), a relatively poorly known papilionoid legume genus, is presented. Rafnia (family Fabaceae, tribe Crotalarieae) is subendemic to the fynbos region of the Western and Eastern Cape Provinces of South Africa, with one species having a distribution area reaching into KwaZulu-Natal. The species delimitation has been unsatisfactory, and the relationships among the taxa uncertain. Rafnia is ...

Scavenging in the genus Natrix

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Cesar Ayres

2012-07-01

Full Text Available Scavenging is reported as an unusual behaviour of snakes. However, it is likely more common than is supposed. Here I report the use of dead newts as prey source by water snakes of the genus Natrix at a dam in north-western Spain. Juveniles and adults viperine snakes (Natrix maura, and also an adult grass snake (Natrix natrix were found feeding on newt carcasses.