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Sample records for acp diaphorina citri

  1. Movement of Diaphorina citri Kuwayama (Hemiptera: Liviidae) adults between huanglongbing-affected and healthy citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a vector transmitting the pathogen of citrus huanglongbing (HLB, also called yellow shoot disease or citrus greening disease). A typical symptom of citrus HLB is leaf yellowing. ACP adults behaved differently on HLB-affe...

  2. Disrupting mating behavior of Diaphorina citri (Liviidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Severe economic damage from citrus greening disease, caused by ‘Candidatus Liberibacter asiaticus’ bacteria, has stimulated development of methods to reduce mating and reproduction in populations of its insect vector, Diaphorina citri (Hemiptera: Liviidae). Male D. citri find mating partners by walk...

  3. Novel reovirus in Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We discovered a psyllid-infecting Reovirus that we are now examining as a potential biological control agent of the Asian citrus psyllid (Diaphorina citri) to reduce huanglongbing disease (HLB) of citrus, a devastating bacterial disease of citrus transmitted by the psyllid. Previously, a psyllid-inf...

  4. Asian citrus psyllid genome (Diaphorina citri, Hemiptera)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Psyllid genome is a scientific breakthrough in that it opens the psyllid genetic blueprint to investigations of all questions ranging from taxonomic origins to the understanding of developmental biology, to the acquisition and transmission of pathogens. The Asian citrus psyllid, Diaphorina citri...

  5. Host-choice behavior of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) under laboratory conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is the vector of huanglongbing (HLB), considered to be the most devastating disease of citrus worldwide. Knowledge of the ACP’s host-plant finding behavior aids in our understanding of the epidemiology of HLB and in designing experiments to ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  7. Correlation of an electrical penetration graph waveform with walking by Asian citrus psyllid, Diaphorina citri Kuwayama

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electrical penetration graph (EPG) monitoring is being used to study how feeding behavior of the Asian citrus psyllid (ACP) (Diaphorina citri Kuwayama) changes in response to insecticides, in an effort to improve the efficacy of widespread insecticide treatments against the insect in Florida citrus....

  8. Incidence of invasive Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae) and its introduced parasitoid Tamarixia radiata (Hymenoptera: Eulophidae) in Florida citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae) vectors the bacterium Candidatus Liberibacter asiaticus, one of the causal organisms of Huanglongbing or citrus greening, a devastating disease of citrus. A eulophid parasitoid, Tamarixia radiata Waterson, was imported ...

  9. Ultrastructure of the salivary glands and bacteria-like structures in the gut and other organs of the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae), vector of huanglongbing disease bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP, Diaphorina citri, Hemiptera, Liviidae) is the principal vector of Candidatus Liberibacter asiaticus (Las), the bacterium associated with huanglongbing (HLB) or citrus greening, currently the most serious citrus disease worldwide. Liberibacter asiaticus is transmitted i...

  10. Effects of freezes on survival of Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus in Florida is occasionally subjected to freezing temperatures. No information was available on the effect of freezing temperatures on mortality of Asian citrus psyllid (Diaphorina citri) in Florida. Studies were therefore initiated to assess mortality rates of D. citri eggs, nymphs and adults...

  11. Postharvest quarantine treatments for Diaphorina citri on infested curry leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies were conducted to evaluate treatments that reduce survival and attachment of Diaphorina citri nymphs on infested curry leaves (Bergera koenigii). Decontamination of curry leaves infested with D. citri in relation to disinfectant (none or Pro-San), temperature (0, 40, and 50°C), and treatment...

  12. Temporal response and attraction of Diaphorina citri to visual stimuli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As the vector of the global disease of citrus greening or huanglongbing, Asian citrus pysllids, Diaphorina citri Kuwayama (Hemiptera; Liviidae) are the greatest threat to the worldwide citrus industry. Critical to management of D. citri and huanglongbing, is optimization of surveillance methodologie...

  13. Insecticide sprays, natural enemy assemblages and predation on Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae).

    PubMed

    Monzo, C; Qureshi, J A; Stansly, P A

    2014-10-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is considered a key citrus pest due to its role as vector of 'huanglongbing' (HLB) or citrus greening, probably the most economically damaging disease of citrus. Insecticidal control of the vector is still considered a cornerstone of HLB management to prevent infection and to reduce reinoculation of infected trees. The severity of HLB has driven implementation of intensive insecticide programs against ACP with unknown side effects on beneficial arthropod fauna in citrus agroecosystems. We evaluated effects of calendar sprays directed against this pest on natural enemy assemblages and used exclusion to estimate mortality they imposed on ACP populations in citrus groves. Predator exclusion techniques were used on nascent colonies of D. citri in replicated large untreated and sprayed plots of citrus during the four major flushing periods over 2 years. Population of spiders, arboreal ants and ladybeetles were independently assessed. Monthly sprays of recommended insecticides for control of ACP, adversely affected natural enemy populations resulting in reduced predation on ACP immature stages, especially during the critical late winter/early spring flush. Consequently, projected growth rates of the ACP population were greatest where natural enemies had been adversely affected by insecticides. Whereas, this result does not obviate the need for insecticidal control of ACP, it does indicate that even a selective regimen of sprays can impose as yet undetermined costs in terms of reduced biological control of this and probably other citrus pests. PMID:24830653

  14. Morphometric comparisons of Diaphorina citri (Hemiptera: Liviidae) populations from Iran, USA and Pakistan

    PubMed Central

    Lashkari, Mohammadreza; Hentz, Matthew G.

    2015-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), vector of citrus greening disease pathogen, Huanglongbing (HLB), is considered the most serious pest of citrus in the world. Prior molecular based studies have hypothesized a link between the D. citri in Iran and the USA (Florida). The purpose of this study was to collect morphometric data from D. citri populations from Iran (mtCOI haplotype-1), Florida (mtCOI haplotype-1), and Pakistan (mtCOI haplotype-6), to determine whether different mtCOI haplotypes have a relationship to a specific morphometric variation. 240 samples from 6 ACP populations (Iran—Jiroft, Chabahar; Florida—Ft. Pierce, Palm Beach Gardens, Port St. Lucie; and Pakistan—Punjab) were collected for comparison. Measurements of 20 morphological characters were selected, measured and analysed using ANOVA and MANOVA. The results indicate differences among the 6 ACP populations (Wilks’ lambda = 0.0376, F = 7.29, P < 0.0001). The body length (BL), circumanal ring length (CL), antenna length (AL), forewing length (WL) and Rs vein length of forewing (RL) were the most important characters separating the populations. The cluster analysis showed that the Iran and Florida populations are distinct from each other but separate from the Pakistan population. Thus, three subgroups can be morphologically discriminated within D. citri species in this study, (1) Iran, (2) USA (Florida) and (3) Pakistan population. Morphometric comparisons provided further resolution to the mtCOI haplotypes and distinguished the Florida and Iranian populations. PMID:26038715

  15. Morphometric comparisons of Diaphorina citri (Hemiptera: Liviidae) populations from Iran, USA and Pakistan.

    PubMed

    Lashkari, Mohammadreza; Hentz, Matthew G; Boykin, Laura M

    2015-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), vector of citrus greening disease pathogen, Huanglongbing (HLB), is considered the most serious pest of citrus in the world. Prior molecular based studies have hypothesized a link between the D. citri in Iran and the USA (Florida). The purpose of this study was to collect morphometric data from D. citri populations from Iran (mtCOI haplotype-1), Florida (mtCOI haplotype-1), and Pakistan (mtCOI haplotype-6), to determine whether different mtCOI haplotypes have a relationship to a specific morphometric variation. 240 samples from 6 ACP populations (Iran-Jiroft, Chabahar; Florida-Ft. Pierce, Palm Beach Gardens, Port St. Lucie; and Pakistan-Punjab) were collected for comparison. Measurements of 20 morphological characters were selected, measured and analysed using ANOVA and MANOVA. The results indicate differences among the 6 ACP populations (Wilks' lambda = 0.0376, F = 7.29, P < 0.0001). The body length (BL), circumanal ring length (CL), antenna length (AL), forewing length (WL) and Rs vein length of forewing (RL) were the most important characters separating the populations. The cluster analysis showed that the Iran and Florida populations are distinct from each other but separate from the Pakistan population. Thus, three subgroups can be morphologically discriminated within D. citri species in this study, (1) Iran, (2) USA (Florida) and (3) Pakistan population. Morphometric comparisons provided further resolution to the mtCOI haplotypes and distinguished the Florida and Iranian populations. PMID:26038715

  16. Endosymbiotic microbiota of Asian Citrus Psyllid (Diaphorina citri)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The causes of huanglongbing may be induced by more than one microbial agent. Thus, we examined the microbial community in the Asian citrus psyllid (AsCP) (Diaphorina citri, Hemiptera: Psyllidae). Citrus greening is one of the most severe diseases of citrus in Asia and Africa and is caused by an uncu...

  17. The complete mitochondrial genome sequence of Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The first complete mitochondrial genome (mitogenome) sequence of Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), from Guangzhou, China is presented. The circular mitogenome is 14,996 bp in length with an A+T content of 74.5%, and contains 13 protein-coding genes (PCGs), 22 tRNA genes ...

  18. Behavioral plasticity in Diaphorina citri feeding on different citrus tissues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian Citrus Psyllid (Diaphorina citri) is a vector of Candidatus Liberibacter asiaticus (CLas), a phloem-limited bacterial pathogen of citrus. While psyllid nymphs are obligate feeders on young flush leaves, adults can be found on leaves of any age. To understand risk of transmission of CLas, i...

  19. Asian citrus psyllid genome (Diaphorina citri, Hemiptera)-Update 2013

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The psyllid genome is a scientific breakthrough that opens the psyllid genetic blueprint to investigations of all questions ranging from taxonomic origins to the understanding of developmental biology, to the acquisition and transmission of pathogens. The Asian citrus psyllid, Diaphorina citri (Hemi...

  20. Vibrational communication between the sexes in Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined the substrate-borne vibrational signals used in communication between the sexes in Diaphorina citri Kuwayama (Hemiptera: Psyllidae), a vector of huanglongbing (an economically devastating disease of citrus), in an anechoic chamber and an olfactometer. Males and females both primarily pro...

  1. Biology, history and world status of Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama, is an important pest of citrus because it transmits phloem-limited bacteria (Candidatus Liberibacter spp.) responsible for citrus greening disease (huanglongbing), considered the world’s most serious disease of citrus. The psyllid has slowly spre...

  2. Establishment of Asian citrus psllid (Diaphorina citri) primary cultures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new cell line was developed from the Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae), as a novel approach to culture the bacteria associated with huanglongbing disease (HLB), also known as citrus greening disease. Methods to culture the phloem-inhabiting bacterium Candidatus L...

  3. Biology, history and world status of Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama, is an important pest of citrus because it transmits phloem-limited bacteria (Candidatus Liberibacter spp.) responsible for citrus greening disease (huanglongbing), considered by some to be the world’s most serious disease of citrus. The psyllid ha...

  4. Complete Genome Sequence of the Largest Known Flavi-Like Virus, Diaphorina citri flavi-like virus, a Novel Virus of the Asian Citrus Psyllid, Diaphorina citri.

    PubMed

    Matsumura, Emilyn E; Nerva, Luca; Nigg, Jared C; Falk, Bryce W; Nouri, Shahideh

    2016-01-01

    A novel flavi-like virus tentatively named Diaphorina citri flavi-like virus (DcFLV) was identified in field populations of Diaphorina citri through small RNA and transcriptome sequencing followed by reverse transcription (RT)-PCR. We report here the complete nucleotide sequence and genome organization of DcFLV, the largest flavi-like virus identified to date. PMID:27609921

  5. Targeting juvenile hormone metabolic genes in the Asian citrus psyllid (Diaphorina citri Kuwayama) as a strategy to reduce the spread of citrus greening disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaphorina citri Kuwayama, the Asian citrus psyllid (ACP), is a devastating citrus pest due to its transmission of a phloem-limited bacterial pathogen, Candidatus Liberibacter asiaticus, that causes citrus greening. Psyllid control is a major part of effective greening disease management, and our r...

  6. Diaphorina citri (Hemiptera:Liviidae) abundance in Puerto Rico declines with elevation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaphorina citri is the primary vector of Hunglongbing disease, the most devastating disease of citrus. Diaphorina citri populations in Puerto Rico were monitored with yellow sticky traps on citrus trees at different elevations, ranging from 10 to 880 m above sea level. Trapping was conducted in Mar...

  7. Complete Genome Sequence of a Putative Densovirus of the Asian Citrus Psyllid, Diaphorina citri

    PubMed Central

    Nigg, Jared C.; Nouri, Shahideh

    2016-01-01

    Here, we report the complete genome sequence of a putative densovirus of the Asian citrus psyllid, Diaphorina citri. Diaphorina citri densovirus (DcDNV) was originally identified through metagenomics, and here, we obtained the complete nucleotide sequence using PCR-based approaches. Phylogenetic analysis places DcDNV between viruses of the Ambidensovirus and Iteradensovirus genera. PMID:27469948

  8. Complete Genome Sequence of a Putative Densovirus of the Asian Citrus Psyllid, Diaphorina citri.

    PubMed

    Nigg, Jared C; Nouri, Shahideh; Falk, Bryce W

    2016-01-01

    Here, we report the complete genome sequence of a putative densovirus of the Asian citrus psyllid, Diaphorina citri Diaphorina citri densovirus (DcDNV) was originally identified through metagenomics, and here, we obtained the complete nucleotide sequence using PCR-based approaches. Phylogenetic analysis places DcDNV between viruses of the Ambidensovirus and Iteradensovirus genera. PMID:27469948

  9. Complete Genome Sequence of Diaphorina citri-associated C virus, a Novel Putative RNA Virus of the Asian Citrus Psyllid, Diaphorina citri.

    PubMed

    Nouri, Shahideh; Salem, Nidà; Falk, Bryce W

    2016-01-01

    We present here the complete nucleotide sequence and genome organization of a novel putative RNA virus identified in field populations of the Asian citrus psyllid, Diaphorina citri, through sequencing of the transcriptome followed by reverse transcription-PCR (RT-PCR). We tentatively named this virus Diaphorina citri-associated C virus (DcACV). DcACV is an unclassified positive-sense RNA virus. PMID:27445370

  10. Complete Genome Sequence of Diaphorina citri-associated C virus, a Novel Putative RNA Virus of the Asian Citrus Psyllid, Diaphorina citri

    PubMed Central

    Nouri, Shahideh; Salem, Nidà

    2016-01-01

    We present here the complete nucleotide sequence and genome organization of a novel putative RNA virus identified in field populations of the Asian citrus psyllid, Diaphorina citri, through sequencing of the transcriptome followed by reverse transcription-PCR (RT-PCR). We tentatively named this virus Diaphorina citri-associated C virus (DcACV). DcACV is an unclassified positive-sense RNA virus. PMID:27445370

  11. Odorants for Surveillance and Control of the Asian Citrus Psyllid (Diaphorina citri)

    PubMed Central

    Coutinho-Abreu, Iliano V.; Forster, Lisa; Guda, Tom; Ray, Anandasankar

    2014-01-01

    Background 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. Results 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%. Conclusion 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. PMID:25347318

  12. Botanicals, selective insecticides, and predators to control Diaphorina citri (Hemiptera: Liviidae) in citrus orchards.

    PubMed

    Khan, Azhar A; Afzal, Muhammad; Qureshi, Jawwad A; Khan, Arif M; Raza, Abubakar M

    2014-12-01

    The Asian citrus psyllid (ACP) Diaphorina citri Kuwayama vectors pathogens that cause huanglongbing (HLB) or citrus greening devastating and economically important disease present in most citrus growing regions. Young citrus shoots are required for psyllid reproduction and development. During winter citrus trees produce little or no new growth. Overwintering adults reproduce in spring on newly emerging shoots also attractive to other pests and beneficial insects. Botanicals and relatively selective insecticides could help to conserve beneficial insects and reduce pest resistance to insecticides. Sprays of Azadirachtin (Neem), Tropane (Datura), Spirotetramat, Spinetoram, and broad-spectrum Imidacloprid were evaluated to control ACP in spring and summer on 10-year-old "Kinow" Citrus reticulata Blanco trees producing new growth. Psyllid populations were high averaging 5-9 nymphs or adults per sample before treatment application. Nymphs or adults were significantly reduced to 0.5-1.5 per sample in all treatments for 3 weeks, average 61%-83% reduction. No significant reduction in ladybeetles Adalia bipunctata, Aneglei scardoni, Cheilomenes sexmaculata, and Coccinella septempunctata was observed. Syrphids, spiders and green lacewings were reduced in treated trees except with Tropane. Studies are warranted to assess impact of these predators on ACP and interaction with insecticides. Observed reduction in ACP populations may not be enough considering its reproductive potential and role in the spread of HLB. Follow-up sprays may be required to achieve additional suppression using rotations of different insecticides. PMID:25205398

  13. Young citrus leaves decrease dispersal distance of Diaphorina citri Kuwayama (Hemiptera: Liviidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To manage citrus Huanglongbing, understanding factors that affect dispersal behavior of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is required to answer questions related to disease epidemiology and to improve management tactics. Currently, little is known about cues medi...

  14. Daily timing of and age at mating in Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The psyllid Diaphorina citri Kuwayama vectors a bacterium, Candidatus Liberibacter asiaticus, in Florida which is responsible for citrus greening disease (huanglongbing), one of the most serious diseases of citrus. Despite the great economic importance of D. citri to citrus production, little is kno...

  15. Multimodal cues drive host-plant assessment in Asian citrus psyllid (Diaphorina citri)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asian citrus psyllid (Diaphorina citri) transmits the causal agent of Huanglongbing, a devastating disease of citrus trees. In this study, we measured behavioral responses of D. citri to combinations of visual, olfactory, and gustatory stimuli in test arenas. Stimuli were presented to the psyllids ...

  16. Coccinellid predators do not track populations of the Asian citrus phyllid (Diaphorina citri) in citrus in Puerto Rico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yellow sticky cards were used to survey populations of Diaphorina citri, the vector of Huanglongbing, the most devastating bacterial disease of citrus worldwide. The numbers of coccinellids, potential predators of Diaphorina citri, were also surveyed. Citrus surveyed included a variety of species (V...

  17. Survey of endosymbionts in the Diaphorina citri metegenome and assembly of a Wolbachia wDi draft genome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaphorina citri, the Asian citrus psyllid,(Hemiptera) is the insect vector of Candidatus Liberibacter asiaticus, the presumed cause of citrus greening disease, known as huanglongbing. Sequencing of the Diaphorina citri metagenome has been initiated to gain better understanding of the biology of D. ...

  18. Detection and characterization of a novel reovirus in the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We successfully used a genomics approach to discover viral pathogens in the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae). These psyllids are vectors of the devastating disease, Huanglongbing, now affecting citrus in the USA, and world wide. Discovery of viral pathogens of psyllids m...

  19. Effect of plant barriers and citrus leaf age on dispersal of Diaphorina citri Kuwayama (Hemiptera: Liviidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    BACKGROUND: Studies designed to measure dispersal capacity of Diaphorina citri Kuwayama (Hemiptera: Liviidae) are needed to provide epidemiological knowledge necessary to improve management of citrus Huanglongbing. In the present study, a mark-release-recapture technique was used to investigate whet...

  20. Chemical and behavioral analysis of the cuticular hydrocarbons from Asian citrus psyllid, Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is the most destructive disease of citrus worldwide. Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the vector of the phloem-inhabiting bacterium, Candidatus Liberibacter asiaticus, which is presumed to cause HLB. Laboratory and field studies were cond...

  1. FK506-binding protein from adult Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We successfully identified a new member of the FK-binding proteins from the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae). FK-binding proteins (FKBP) function in many critical pathways needed for psyllid survival. The full length mRNA transcript provides us a new genetic target for ...

  2. Behavioral evidence for a female-produced sex attractant in Diaphorina citri Kuwayama (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is an important world-wide pest of citrus. It vectors three phloem-restricted bacteria in the genus Candidatus Liberibacter that cause huanglongbing (citrus greening disease). Studies were conducted to examine the behavioral responses of male and fema...

  3. Midgut gene expression in Asian citrus psyllid (Hemiptera: Psyllidae) Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We produced a gene expression dataset from the midgut tissues of the Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae). The AsCP is the primary vector of the bacterium associated with a devastating citrus disease known as huanglongbing (HLB). The occurrence and spread of the AsCP ...

  4. Draft Genome Sequence of "Candidatus Liberibacter asiaticus" from Diaphorina citri in Guangdong, China.

    PubMed

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

    2015-01-01

    The draft genome sequence of "Candidatus Liberibacter asiaticus" strain YCPsy from an Asian citrus psyllid (Diaphorina citri) in Guangdong, China, is reported here. The YCPsy strain has a genome size of 1,233,647 bp, 36.5% G+C content, 1,171 open reading frames (ORFs), and 53 RNAs. PMID:26543132

  5. Internal extracellular bacteria of Diaphorina citri Kuwayama (Hemiptera: Psyllidae), the Asian citus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Internal bacteria were isolated and cultured from the Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), the insect which transmits the plant-infecting bacteria, Candidatus Liberibacter, known to infect and kill citrus trees, known as citrus greening disease. The bacteria from Di...

  6. Draft genome sequence of “Candidatus Liberibacter asiaticus” from Diaphorina citri in Guangdong, China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The draft genome sequence of “Candidatus Liberibacter asiaticus” strain YCPsy from an Asian citrus psyllid (Diaphorina citri) in Guangdong of China is reported. The YCPsy strain has a genome size of 1,233,647 bp, 36.5% G+C content, 1,171 open reading frames (ORFs), and 53 RNAs....

  7. Draft Genome Sequence of “Candidatus Liberibacter asiaticus” from Diaphorina citri in Guangdong, China

    PubMed Central

    Wu, F.; Zheng, Z.; Cen, Y.; Liang, G.

    2015-01-01

    The draft genome sequence of “Candidatus Liberibacter asiaticus” strain YCPsy from an Asian citrus psyllid (Diaphorina citri) in Guangdong, China, is reported here. The YCPsy strain has a genome size of 1,233,647 bp, 36.5% G+C content, 1,171 open reading frames (ORFs), and 53 RNAs. PMID:26543132

  8. Gender differences and effect of photophase on Asian citrus psyllid (Diaphorina citri Kuwayama) feeding behavior

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), thought to be primarily a phloem-feeding insect, transmits the presumptive pathogen for Huanglongbing, ‘Candidatus Liberibacter asiaticus’. Because this bacterium is restricted to the phloem and bacterial transmission is the res...

  9. Gene expression in midgut tissues of Diaphorina citri: Application to biology and vector control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We produced a gene expression dataset from the midgut tissues of the Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae). The AsCP is the primary vector associated with the spread of a devastating citrus trees disease, huanglongbing (HLB). The occurrence and spread of the AsCP and H...

  10. Responses of Diaphorina citri (Hemiptera: Psyllidae) to conspecific vibrational signals and synthetic mimics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mate-seeking in Diaphorina citri Kuwayama, a vector of the economically damaging huanglongbing citrus disease, typically includes male-female duetting behaviors. First, the male calls by beating its wings at ca. 170-250 Hz, producing vibrations that are transmitted along the host tree branches to th...

  11. Dispersion patterns and sampling plans for Diaphorina citri (Hemiptera: Psyllidae) in citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The abundance and spatial dispersion of the Asian citrus psyllid, Diaphorina citri Kuwayama, were studied in thirty-four grapefruit (Citrus × paradisi) and six sweet orange (Citrus sinensis) orchards from March to August 2006 when the pest is more abundant in southern Texas. Although flush shoot inf...

  12. An improved method of DNA extraction from Diaphorina citri for HLB detection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a devastating disease of citrus that is transmitted by two citrus psyllids. Diaphorina citri transmits Candidatus Liberibacter asiaticus (Las) and Ca. L. americanus (Lam), and Trioza erytreae transmits Ca. L. africanus (Laf). Ca. Liberibacter species can be detected in DNA ex...

  13. The influence of learning on host plant preference in a significant phytopathogen vector, Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri, vector ...

  14. Relationships between adult abdominal color and reproductive potential in Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaphorina citri Kuwayama (Hemiptera: Psyllidae), a vector of huanglongbing (citrus greening disease), exhibits three more or less distinct abdominal colors in the adult stage: gray/brown, blue/green, and orange/yellow. A previous report showed that—relative to blue/green individuals—gray/brown indi...

  15. Importance of multiple mating to female reproductive output in Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluate the importance of multiple mating to female reproductive output in Diaphorina citri Kuwayama (Hemiptera: Psyllidae) by grouping individual females with one or three males for 24 h (short duration) or two weeks (long duration) and examining oviposition over 18-19 days. For the short durat...

  16. Flight activity of Diaphorina citri in and around a citrus grove

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to assess flight activity by Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) in and around a Florida citrus grove. Yellow sticky card traps were deployed within citrus trees and on 3 meter poles scattered within the grove near trees and at various distanc...

  17. Recapture rate of diaphorina citri kuwayama (hemiptera: psyllidae) marked with fluorescent dust in dispersal studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Knowledge on the dispersal capacity of the insect vector Diaphorina citri Kuwayama is necessary to answer questions related to Huanglongbing epidemiology and improve current management strategies for the disease. The objectives of this field study were to determine the recapture rate and distance o...

  18. Antifeedant and lethal effects of the fungi Isaria fumosorosea on the Asian citrus psyllid Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An insect-infecting fungal pathogen increases mortality of Asian citrus psyllids (Diaphorina citri,Hemiptera:Psyllidae). The entomopathogenic fungi(Isaria fumosorosea [Ifr])sold as the product PFR 97™ was shown to be effective at killing and reducing feeding of the Asian citrus psyllid. The psyllid ...

  19. Population ecology and phenology of Diaphorina citri (Hemiptera: Psyllidae) in two Florida citrus groves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies were conducted during 2005 and 2006 to assess population densities and phenology of the psyllid Diaphorina citri Kuwayama in citrus within east central Florida. Young, irrigated grapefruit and mature, non-irrigated orange trees were sampled weekly for eggs, nymphs and adults on flush shoots;...

  20. Impact of different temperatures on survival and energy metabolism in the Asian citrus psyllid, Diaphorina citri Kuwayama.

    PubMed

    El-Shesheny, Ibrahim; Hijaz, Faraj; El-Hawary, Ibrahim; Mesbah, Ibrahim; Killiny, Nabil

    2016-02-01

    Temperature influences the life history and metabolic parameters of insects. Asian citrus psyllid (ACP), Diaphorina citri is a tropical and subtropical pest. ACP invaded new regions around the world and threatened the citrus industry as a vector for Huanglongbing (HLB) disease. ACP is widely distributed and can survive high (up to 45 °C) and low temperatures (as low as -6 °C). The precise mechanism of temperature tolerance in ACP is poorly understood. We investigated adult survival, cellular energy balance, gene expression, and nucleotide and sugar-nucleotide changes under the effect of different temperature regimes (0 °C to 45 °C with 5 °C intervals). The optimum temperatures for survival were 20 and 25 °C. Low temperatures of 0 °C and 5 °C caused 50% mortality after 2 and 4 days respectively, while one day at high temperature (40 °C and 45 °C) caused more than 95% mortality. The lowest quantity of ATP (3.69 ± 1.6 ng/insect) and the maximum ATPase enzyme activities (57.43 ± 7.6 μU/insect) were observed at 25 °C. Correlation between ATP quantities and ATPase activity was negative. Gene expression of hsp 70, V-type proton ATPase catalytic subunit A and ATP synthase α subunit matched these results. Twenty-four nucleotides and sugar-nucleotides were quantified using HPLC in ACP adults maintained at low, high, and optimum temperatures. The nucleotide profiles were different among treatments. The ratios between AMP:ATP and ADP:ATP were significantly decreased and positively correlated to adults survival, whereas the adenylate energy charge was increased in response to low and high temperatures. Exploring energy metabolic regulation in relation with adult survival might help in understanding the physiological basis of how ACP tolerates newly invaded regions. PMID:26603556

  1. Endosymbiont hunting in the metagenome of Asian citrus psyllid (Diaphorina citri) (7th Annual SFAF Meeting, 2012)

    ScienceCinema

    Saha, Surya [Cornell University

    2013-02-12

    Surya Saha on "Endosymbiont hunting in the metagenome of Asian citrus psyllid (Diaphorina citri)" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  2. Endosymbiont hunting in the metagenome of Asian citrus psyllid (Diaphorina citri) (7th Annual SFAF Meeting, 2012)

    SciTech Connect

    Saha, Surya

    2012-06-01

    Surya Saha on "Endosymbiont hunting in the metagenome of Asian citrus psyllid (Diaphorina citri)" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  3. Diaphorina citri (Hemiptera: Psyllidae) infection and dissemination of the entomopathogenic fungus Isaria fumosorosea (Hypocreales: Cordycipitaceae)under laboratory conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method was developed to increase efficacy and reduce grower costs when using the biological control fungal agent Paecilomyces fumosoroseus blastospores (Deuteromycotina: Hyphomycetes) to infect adult Asian citrus psyllids, Diaphorina citri (Psyllidae: Hemiptera). We analyzed the efficacy of this ‘...

  4. Repellent Activity of Botanical Oils against Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae).

    PubMed

    Kuhns, Emily H; Martini, Xavier; Hoyte, Angel; Stelinski, Lukasz L

    2016-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama, is the insect vector of the pathogen causing huanglongbing. We selected three botanical oils to evaluate behavioral activity against D. citri. In laboratory olfactometer assays, fir oil was repellent to D. citri females, while litsea and citronella oils elicited no response from D. citri females. In choice settling experiments, D. citri settled almost completely on control plants rather than on plants treated with fir oil at a 9.5 mg/day release rate. Therefore, we conducted field trials to determine if fir oil reduced D. citri densities in citrus groves. We found no repellency of D. citri from sweet orange resets that were treated with fir oil dispensers releasing 10.4 g/day/tree as compared with control plots. However, we found a two-week decrease in populations of D. citri as compared with controls when the deployment rate of these dispensers was doubled. Our results suggest that treatment of citrus with fir oil may have limited activity as a stand-alone management tool for D. citri and would require integration with other management practices. PMID:27429006

  5. Incidence of the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae) and its parasitoid Tamarixia radiata (Hymenoptera: Eulophidae) in Florida citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaphorina citri Kuwayama, vectors the bacterium Candidatus Liberibacter asiaticus, one of the causal organisms of the devastating citrus disease “huanglongbing” or citrus greening. In the United States, D. citri was first discovered in Florida, in 1998. Tamarixia radiata Waterston, was imported fro...

  6. Effects of a particle film on biology and behavior of Diaphorina citri (Hemiptera: Psyllidae) and its infestations in citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies were conducted to investigate the effects of a kaolin-based hydrophilic particle film, Surround WP, on the biology and behavior of the psyllid Diaphorina citri Kuwayama, and to assess population densities of D. citri in citrus subjected to monthly applications of Surround WP. Laboratory inve...

  7. Diaphorina citri (Hemiptera: Liviidae) responses to microcontroller-buzzer communication signals of potential use in vibration traps

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Monitoring of Diaphorina citri Kuwayama populations is an important component of efforts to reduce damage caused by huanglongbing, a devastating disease it vectors in citrus groves. Currently, D. citri is monitored primarily by unbaited sticky traps or visual inspection of trees. A potentially more ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  9. A COMPARISON OF TRAPS AND TAP SAMPLING FOR MONITORING ADULT ASIAN CITRUS PSYLLID, DIAPHORINA CITRI KUWAYMA (HOMOPTERA: PSYLLIDAE), IN CITRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama, was first found in Florida during June 1998 and subsequently spread throughout the state's citrus-growing regions. D. citri vectors the bacterium, Candidatus Liberibacter asiaticus, responsible for citrus greening disease (huanglongbing). Citrus g...

  10. First record of Diaphorina citri (Hemiptera: Psyllidae) in Ecuador infesting urban citrus and orange jasmine trees.

    PubMed

    Cornejo, J F; Chica, E J

    2014-01-01

    Adults and nymphs of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), were collected in the Guayaquil, Samborondón, and Durán cantons in coastal Ecuador. Psyllids were found in high numbers in citrus (Citrus spp., Sapindales: Rutaceae) and orange jasmine (Murraya exotica [L.] Jack, Sapindales: Rutaceae) trees within the Guayaquil-Samborondon-Duran conurbation; however, none was found during scoutings in the main citrus producing areas in coastal Ecuador. To the best of our knowledge, this is the first report of D. citri in Ecuador and the Pacific coastal plain of South America. PMID:25527601

  11. Attraction of Diaphorina citri (Hemiptera: Liviidae) to colored light

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The most devasting disease of citrus, huanglongbing (HLB), is spread by the insect vector the Asian Citrus Psyllid (ACP). Although ACP are known to respond to visual cues, previous studies have not documented the specific wavelengths of light attractive to ACP. The objectives of this study were to...

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

    PubMed Central

    Wu, F.; Deng, X.; Huang, J.; Cen, Y.

    2015-01-01

    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. PMID:26543117

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

    PubMed

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

    2015-01-01

    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. PMID:26543117

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

    PubMed

    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. PMID:26846216

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

    PubMed

    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. PMID:26470202

  16. Chemical and behavioral analysis of the cuticular hydrocarbons from Asian citrus psyllid, Diaphorina citri.

    PubMed

    Mann, Rajinder S; Rouseff, Russell L; Smoot, Jack; Rao, Nandikeswara; Meyer, Wendy L; Lapointe, Stephen L; Robbins, Paul S; Cha, Dong; Linn, Charles E; Webster, Francis X; Tiwari, Siddharth; Stelinski, Lukasz L

    2013-06-01

    Huanglongbing (HLB) is the most destructive disease of citrus worldwide. The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the vector of the phloem-inhabiting bacterium, Candidatus Liberibacter asiaticus, which is presumed to cause HLB in Florida citrus. Laboratory and field studies were conducted to examine the behavioral responses of male and female D. citri to their cuticular extracts. In olfactometer assays, more male D. citri were attracted to one, five, or 10 female cuticular extract equivalent units than blank controls. The results were confirmed in field studies in which clear or yellow traps baited with 10 female cuticular extract equivalent units attracted proportionately more males than clear traps baited with male cuticular extract or unbaited traps. Analyses of cuticular constituents of male and female D. citri revealed differences between the sexes in chemical composition of their cuticular extracts. Laboratory bioassays with synthetic chemicals identified from cuticular extracts indicated that dodecanoic acid attracted more males than clean air. Traps baited with dodecanoic acid did not increase total catch of D. citri as compared with blank traps at the dosages tested; however, the sex ratio of psyllid catch was male biased on traps baited with the highest lure loading dosage tested (10.0 mg). PMID:23955888

  17. The Genetic Structure of an Invasive Pest, the Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae)

    PubMed Central

    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. PMID:25545788

  18. The genetic structure of an invasive pest, the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae).

    PubMed

    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. PMID:25545788

  19. Diaphorina citri (Hemiptera: Liviidae) Abundance in Puerto Rico Declines with Elevation.

    PubMed

    Jenkins, David A; Hall, David G; Goenaga, Ricardo

    2015-02-01

    Diaphorina citri Kuwayama is the primary vector of Huanglongbing, the most devastating disease of citrus. D. citri populations in Puerto Rico were monitored with yellow sticky traps on citrus trees or other psyllid host plants at different elevations, ranging from 10 to 880 m above sea level. Trapping was conducted in March through May of 2013 and 2014 when psyllid populations usually are highest. Population levels of D. citri, based on the trapping data, varied among the sites, and there was a strong trend in both years for decreasing psyllid abundance with increased elevation based on the number of psyllids captured on traps and the proportion of trees shown to be infested. No psyllids were collected at an elevation of >600 m. Reduced populations at higher elevations could be a consequence of differences in temperature, air pressure, oxygen levels, ultraviolet light, or other factors alone or in combination. We discuss our results as they pertain to management of D. citri and Huanglongbing. PMID:26470127

  20. Effects on Asian Citrus Psyllid (Diaphorina citri Kuwayama) feeding behavior of fenpropathrin and chlorpyrifos within 24 hours of application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), also known as citrus greening disease, is one of the most destructive diseases affecting citrus production. The phloem-limited bacterium associated with HLB is transmitted by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). One component of HLB managem...

  1. Twelve polymorphic microsatellite loci from the Asian Citrus Psyllid, Diaphorina citri Kuwayama, the vector for citrus greening disease Huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Twelve polymorphic microsatellite markers were developed from microsatellite-enriched DNA libraries and mined from an EST library of Diaphorina citri, the vector of the devastating citrus greening disease (Huanglongbing). Analysis of 288 individuals from Florida, Texas, and Brazil showed allelic di...

  2. Temperature studies with the Asian citrus psyllid, Diaphorina citri Kuwayama: cold hardiness and temperature thresholds for oviposition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to obtain information on the cold hardiness of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), and to assess upper and lower temperature thresholds for oviposition. The psyllid is an important pest in citrus because it transmits the bacterial pathoge...

  3. An assessment of yellow sticky card traps as indicators of the relative abundance of adult Diaphorina citri in citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yellow sticky card traps were assessed as a tool for estimating infestation levels of adult Diaphorina citri, an important pest of citrus. Weekly trapping was conducted in young and mature trees with traps deployed directly in trees, one trap per tree. In addition, a comparison was made between one ...

  4. Effects of atmospheric pressure trends on calling, mate-seeking, and phototaxis of Diaphorina citri (Hemiptera: Liviidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insects and other animals sometimes modify behavior in response to changes in atmospheric pressure, an environmental cue that can provide warning of potentially injurious windy and rainy weather. To determine if Diaphorina citri (Hemiptera: Liviidae) calling, mate-seeking, and phototaxis behaviors w...

  5. Toxicity of insecticidal soaps to the Asian citrus psyllid (Diaphorina citri) and two of its natural enemies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insecticidal soaps (hereafter “soaps”) are labeled for use by homeowners and also can be used in citrus grown for the organic market. Soaps control some insect pests and therefore might be an alternative to conventional pesticides for control of the Asian citrus psyllid, Diaphorina citri Kuwayama (...

  6. Detection of Candidatus Liberibacter asiaticus in Diaphorina citri and its importance in the management of Citrus Huanglongbing in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB or citrus greening) is a highly destructive disease that has been spreading in both Florida and Brazil. Its psyllid vector, Diaphorina citri, has spread to Texas and Mexico thus threatening the future of citrus production elsewhere in North America. Even though, sensitive d...

  7. Effects of the residual activity of foliar-applied insecticides on Asian citrus psyllid (Diaphorina citri) feeding behavior.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus greening disease, also known as Huanglongbing (HLB), is associated with a phloem-limited bacterium that is transmitted by Asian citrus psyllid, Diaphorina citri Kuwayama. Application of insecticides to reduce psyllid populations is one of the primary methods used for HLB management. However,...

  8. Observations on the entomopathogenic fungus Hirsutella citriformis attacking adult Diaphorina citri (Hemiptera: Psyllid) in a managed citrus grove

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A two-year field study was conducted in an orange grove (0.7 ha) in Florida to characterize the phenology of the entomopathogen Hirsutella citriformis Speare infecting adults of the Asian citrus psyllid, Diaphorina citri Kuwayama. On the average over the two-year study, 23 percent of adults observed...

  9. Antennal and behavioral response of the Asian citrus psyllid (Diaphorina citri Kuwayama) to degradation products of citrus volatiles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae) vectors the bacterial causal pathogen of the deadly citrus disease, Huanglongbing (citrus greening) which is a major threat to citrus industry worldwide. We studied antennal and behavioral responses to principal components of head...

  10. Stylet morphometrics and citrus leaf vein structure in relation to feeding behavior of the Asian citrus psyllid Diaphorina citri, vector of citrus huanglongbing bacterium.

    PubMed

    Ammar, El-Desouky; Hall, David G; Shatters, Robert G

    2013-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae), is the primary vector of the phloem-limited bacterium Candidatus Liberibacter asiaticus (LAS) associated with huanglongbing (HLB, citrus greening), considered the world's most serious disease of citrus. Stylet morphometrics of ACP nymphs and adults were studied in relation to citrus vein structure and to their putative (histologically verified) feeding sites on Valencia orange leaves. ACP nymphs preferred to settle and feed on the lower (abaxial) side of young leaves either on secondary veins or on the sides of the midrib, whereas adults preferred to settle and feed on the upper (adaxial) or lower secondary veins of young or old leaves. Early instar nymphs can reach and probe the phloem probably because the distance to the phloem is considerably shorter in younger than in mature leaves, and is shorter from the sides of the midrib compared to that from the center. Additionally, the thick-walled 'fibrous ring' (sclerenchyma) around the phloem, which may act as a barrier to ACP stylet penetration into the phloem, is more prominent in older than in younger leaves and in the center than on the sides of the midrib. The majority (80-90%) of the salivary sheath termini produced by ACP nymphs and adults that reached a vascular bundle were associated with the phloem, whereas only 10-20% were associated with xylem vessels. Ultrastructural studies on ACP stylets and LAS-infected leaves suggested that the width of the maxillary food canal in first instar nymphs is wide enough for LAS bacteria to traverse during food ingestion (and LAS acquisition). However, the width of the maxillary salivary canal in these nymphs may not be wide enough to accommodate LAS bacteria during salivation (and LAS inoculation) into host plants. This may explain the inability of early instar nymphs to transmit LAS/HLB in earlier reports. PMID:23555830

  11. Behavioral, Ultrastructural and Chemical Studies on the Honeydew and Waxy Secretions by Nymphs and Adults of the Asian Citrus Psyllid Diaphorina citri (Hemiptera: Psyllidae)

    PubMed Central

    Ammar, El-Desouky; Alessandro, Rocco; Shatters Jr, Robert G.; Hall, David G.

    2013-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae) is the primary vector of the bacterium causing citrus huanglongbing (citrus greening), the most serious disease of citrus worldwide. Psyllids and other hemipterans produce large amounts of honeydew, which has been used previously as an indicator of phloem sap composition and insect feeding or metabolism. Behavioral, ultrastructural and chemical studies on ACP, its honeydew and waxy secretions showed important differences between nymphs, males and females, and suggested some mechanisms by which the psyllids, especially nymphs and adult females, can minimize their contamination with honeydew excretions. The anal opening in ACP, near the posterior end of the abdomen, is on the ventral side in nymphs and on the dorsal side in adult males and females. Video recordings showed that adult males produce clear sticky droplets of honeydew gently deposited behind their body on the leaf surface, whereas adult females produce whitish honeydew pellets powerfully propelled away from the female body, probably to get their excretions away from eggs and newly hatched nymphs. ACP nymphs produce long ribbons or tubes of honeydew that frequently stay attached to the exuviae after molting, or drop when feeding on the lower side of citrus leaves. Furthermore, honeydew excretions of both nymphs and adult females are covered with a thin layer of whitish waxy material ultrastructurally composed of a convoluted network of long fine filaments or ribbons. This material is extruded from intricate arrays of wax pores in the circumanal ring (around the anus) that is found in nymphs and females but not in males of ACP or other psyllid species. Infrared microscopy and mass spectroscopy revealed that, in addition to various sugars, honeydew excretions of ACP nymphs and females are covered with a thin layer of wax similar in profile to ester waxes. PMID:23762268

  12. Insecticidal suppression of Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae) vector of huanglongbing pathogens.

    PubMed

    Qureshi, Jawwad A; Kostyk, Barry C; Stansly, Philip A

    2014-01-01

    Diaphorina citri vectors pathogens that cause 'huanglongbing' or citrus greening disease which poses a serious threat to citrus production worldwide. Vector suppression is critical to reduce disease spread. Efficacy is a main concern when choosing an insecticide. Insecticidal treatments of 49 products or 44 active ingredients (a.i) labeled or experimental were field tested between 2005-2013 as foliar sprays (250 treatments, 39 a.i) or soil applications (47 treatments, 9 a.i) to control D. citri in citrus. A combined effect of nymphal and adult suppression in response to sprays of 23 insecticides representing 9 modes of action (MoA) groups and 3 unknown MoA provided more than 90% reduction of adult D. citri over 24-68 days. Observable effects on nymphs were generally of shorter duration due to rapid maturation of flush. However, reduction of 76-100% nymphs or adults over 99-296 days was seen on young trees receiving drenches of the neonicotinoids imidacloprid, thiamethoxam or clothianidin (MoA 4A) and a novel anthranilic diamide, cyantraniliprole (MoA 28). Effective products identified for foliar sprays to control D. citri provide sufficient MoA groups for rotation to delay evolution of insecticide resistance by D. citri and other pests. However, cyantraniliprole is now the only available alternative for rotation with neonicotinoids in soil application to young trees. Sprays of up to eight of the most effective insecticides could be rotated over a year without repetition of any MoA and little or no recourse to neonicotinoids or cyantraniliprole, so important for protection of young trees. Other considerations effecting decisions of what and when to spray include prevalence of huanglongbing, pest pressure, pre-harvest intervals, overall budget, equipment availability, and conservation of beneficial arthropods. Examples of spray programs utilizing broad-spectrum and relatively selective insecticides are provided to improve vector management and may vary depending on

  13. The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri

    PubMed Central

    Stockton, Dara G.; Martini, Xavier; Patt, Joseph M.; Stelinski, Lukasz L.

    2016-01-01

    Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri; vector of the causal agent of citrus greening disease or huanglongbing. We investigated: a) whether development on specific host plant species influenced host plant preference in mature D. citri; and b) the extent of associative learning in D. citri in the form of simple and compound conditioning. Learning was measured by cue selection in a 2-choice behavioral assay and compared to naïve controls. Our results showed that learned responses in D. citri are complex and diverse. The developmental host plant species influenced adult host plant preference, with female psyllids preferring the species on which they were reared. However, such preferences were subject to change with the introduction of an alternative host plant within 24–48 hrs, indicating a large degree of experience-dependent response plasticity. Additionally, learning occurred for multiple sensory modalities where novel olfactory and visual environmental cues were associated with the host plant. However, males and females displayed differing discriminatory abilities. In compound conditioning tasks, males exhibited recognition of a compound stimulus alone while females were capable of learning the individual components. These findings suggest D. citri are dynamic animals that demonstrate host plant preference based on developmental and adult experience and can learn to recognize olfactory and visual host plant stimuli in ways that may be sex specific. These experience-based associations are likely used by adults to locate and select suitable host plants for feeding and reproduction and may suggest the need for more tailored lures and traps, which reflect region-specific cultivars or predominate Rutaceae in the area

  14. The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri.

    PubMed

    Stockton, Dara G; Martini, Xavier; Patt, Joseph M; Stelinski, Lukasz L

    2016-01-01

    Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri; vector of the causal agent of citrus greening disease or huanglongbing. We investigated: a) whether development on specific host plant species influenced host plant preference in mature D. citri; and b) the extent of associative learning in D. citri in the form of simple and compound conditioning. Learning was measured by cue selection in a 2-choice behavioral assay and compared to naïve controls. Our results showed that learned responses in D. citri are complex and diverse. The developmental host plant species influenced adult host plant preference, with female psyllids preferring the species on which they were reared. However, such preferences were subject to change with the introduction of an alternative host plant within 24-48 hrs, indicating a large degree of experience-dependent response plasticity. Additionally, learning occurred for multiple sensory modalities where novel olfactory and visual environmental cues were associated with the host plant. However, males and females displayed differing discriminatory abilities. In compound conditioning tasks, males exhibited recognition of a compound stimulus alone while females were capable of learning the individual components. These findings suggest D. citri are dynamic animals that demonstrate host plant preference based on developmental and adult experience and can learn to recognize olfactory and visual host plant stimuli in ways that may be sex specific. These experience-based associations are likely used by adults to locate and select suitable host plants for feeding and reproduction and may suggest the need for more tailored lures and traps, which reflect region-specific cultivars or predominate Rutaceae in the area

  15. Living on the Edges: Spatial Niche Occupation of Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), in Citrus Groves.

    PubMed

    Sétamou, Mamoudou; Bartels, David W

    2015-01-01

    The spatial niche occupation of the Asian citrus psyllid, Diaphorina citri Kuwayama, 1908, was evaluated to determine its field colonization and food resource exploitation strategies in citrus groves. Mature grapefruit and sweet orange groves were surveyed as part of an area-wide program in 2009-2010 to determine D. citri population densities and between-tree distribution. In both cultivars, significantly more psyllids were found on perimeter trees throughout the study period suggesting a strong edge effect in D. citri distribution in the groves. D. citri densities and infestation levels gradually declined from the edge to the center of grove. Higher numbers of D. citri were recorded on trees located on the east and south sides of the groves than those on the west and north sides. Citrus groves located at the outer edge of the study with at least one side non-surrounded to other citrus groves harbored significantly more D. citri than groves located within the block cluster and entirely surrounded by other groves. In detailed field studies during 2012, infestation of D. citri started from border trees in the grove where possibly one generation is completed before inner trees become infested. In addition, psyllid densities decreased significantly with increasing distance from the grove edge. Using the selection index, D citri exhibited a strong niche occupation preference for border trees. PMID:26193111

  16. Living on the Edges: Spatial Niche Occupation of Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), in Citrus Groves

    PubMed Central

    2015-01-01

    The spatial niche occupation of the Asian citrus psyllid, Diaphorina citri Kuwayama, 1908, was evaluated to determine its field colonization and food resource exploitation strategies in citrus groves. Mature grapefruit and sweet orange groves were surveyed as part of an area-wide program in 2009–2010 to determine D. citri population densities and between-tree distribution. In both cultivars, significantly more psyllids were found on perimeter trees throughout the study period suggesting a strong edge effect in D. citri distribution in the groves. D. citri densities and infestation levels gradually declined from the edge to the center of grove. Higher numbers of D. citri were recorded on trees located on the east and south sides of the groves than those on the west and north sides. Citrus groves located at the outer edge of the study with at least one side non-surrounded to other citrus groves harbored significantly more D. citri than groves located within the block cluster and entirely surrounded by other groves. In detailed field studies during 2012, infestation of D. citri started from border trees in the grove where possibly one generation is completed before inner trees become infested. In addition, psyllid densities decreased significantly with increasing distance from the grove edge. Using the selection index, D citri exhibited a strong niche occupation preference for border trees. PMID:26193111

  17. Biology of the Huanglongbing vector Diaphorina citri (Hemiptera: Liviidae) on different host plants.

    PubMed

    Alves, G R; Diniz, A J F; Parra, J R P

    2014-04-01

    Although many studies have been conducted on the development and reproductive potential of Diaphorina citri Kuwayama, 1908 (Hemiptera: Liviidae) in different host species, few have evaluated these parameters on different varieties of the same host species. This study evaluated the influence of five commercial varieties of citrus (Citrus spp. L.)--Hamlin, Natal, Pêra, Ponkan, and Valencia-and orange jasmine [Murraya exotica (L.) Jack] on the development of D. citri. Survival rates for the egg stage were highest on orange jasmine (85.7%) and on Valencia (83.3%). The lowest viability of the nymphal stage was also observed on Hamlin, averaging 57.4%. Values for total viability ranged from 65.9 to 32.6%, and were highest on Valencia. The longest egg-adult development time was on Natal, with a mean of 18.4 d; the shortest total development time was on orange jasmine, with a mean of 17.3 d. Based on the fertility life table, the net reproductive rate (Ro) of D. citri was 2.5 times higher when reared on Valencia than on Hamlin. The other parameters (duration of each generation [T], finite rate of increase [lambda], and innate capacity to increase in number [r(m)]) also demonstrated that Valencia is best suited to this insect. The results obtained for the biological parameters and the fertility life table indicate that Valencia and orange jasmine were the most suitable hosts, whereas Hamlin was least suitable for the development of D. citri. These results provide information for the installation of new citrus groves, especially in the choice of varieties to be planted and the location of different varieties within the groves, with a view toward the management of Huanglongbing or HLB. PMID:24772551

  18. Overview of worldwide diversity of Diaphorina citri Kuwayama mitochondrial cytochrome oxidase 1 haplotypes: two Old World lineages and a New World invasion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We utilized a Bayesian phylogenetic technique to resolve global relationships of Diaphorina citri populations. This is the first global phylogenetic study of D. citri. New mitochondrial primers were designed from an EST library and an 821 base pair region of the COI was amplified and sequenced. The ...

  19. Incidence of huanglongbing-associated ‘Candidatus Liberibacter Asiaticus’ in Diaphorina citri (Hemiptera: Psyllidae) collected from plants for sale in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama, was reported for the first time in Florida in June 1998, and huanglongbing (HLB, citrus greening), vectored by D. citri, was detected in Florida for the first time in Aug 2005. In Florida, the only known HLB pathogen is ‘Candidatus Liberibacter as...

  20. Internal extracellular bacteria of Diaphorina citri Kuwayama (Hemiptera: Psyllidae), the Asian citrus psyllid.

    PubMed

    Kolora, Lakshmi D; Powell, Christopher M; Hunter, W; Bextine, B; Lauzon, C R

    2015-05-01

    The Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an invasive insect pest that transmits Candidatus Liberibacter spp. This insect/pathogen system was first identified in North America in the early 2000's and has become the top threat to the citrus industry. Limited options for management of this problem exist; therefore, innovative pest management strategies are being developed. In this study, we describe the first step toward a paratransgenic approach (also referred to symbiotic control) for control of the insect vector or the pathogen. Culturable bacteria from the gut of Asian Citrus Psyllids were identified using standard culture techniques followed by sequencing of the cultured microorganisms. Further, 454 pyrosequencing of the gut was performed to audit bacterial presence in order to begin to identify any relationship between psyllid symbionts and C. Liberibacter spp. PMID:25645736

  1. Diverse Array of New Viral Sequences Identified in Worldwide Populations of the Asian Citrus Psyllid (Diaphorina citri) Using Viral Metagenomics

    PubMed Central

    Nouri, Shahideh; Salem, Nidá; Nigg, Jared C.

    2015-01-01

    ABSTRACT The Asian citrus psyllid, Diaphorina citri, is the natural vector of the causal agent of Huanglongbing (HLB), or citrus greening disease. Together; HLB and D. citri represent a major threat to world citrus production. As there is no cure for HLB, insect vector management is considered one strategy to help control the disease, and D. citri viruses might be useful. In this study, we used a metagenomic approach to analyze viral sequences associated with the global population of D. citri. By sequencing small RNAs and the transcriptome coupled with bioinformatics analysis, we showed that the virus-like sequences of D. citri are diverse. We identified novel viral sequences belonging to the picornavirus superfamily, the Reoviridae, Parvoviridae, and Bunyaviridae families, and an unclassified positive-sense single-stranded RNA virus. Moreover, a Wolbachia prophage-related sequence was identified. This is the first comprehensive survey to assess the viral community from worldwide populations of an agricultural insect pest. Our results provide valuable information on new putative viruses, some of which may have the potential to be used as biocontrol agents. IMPORTANCE Insects have the most species of all animals, and are hosts to, and vectors of, a great variety of known and unknown viruses. Some of these most likely have the potential to be important fundamental and/or practical resources. In this study, we used high-throughput next-generation sequencing (NGS) technology and bioinformatics analysis to identify putative viruses associated with Diaphorina citri, the Asian citrus psyllid. D. citri is the vector of the bacterium causing Huanglongbing (HLB), currently the most serious threat to citrus worldwide. Here, we report several novel viral sequences associated with D. citri. PMID:26676774

  2. Insecticidal Suppression of Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae) Vector of Huanglongbing Pathogens

    PubMed Central

    Qureshi, Jawwad A.; Kostyk, Barry C.; Stansly, Philip A.

    2014-01-01

    Diaphorina citri vectors pathogens that cause ‘huanglongbing’ or citrus greening disease which poses a serious threat to citrus production worldwide. Vector suppression is critical to reduce disease spread. Efficacy is a main concern when choosing an insecticide. Insecticidal treatments of 49 products or 44 active ingredients (a.i) labeled or experimental were field tested between 2005–2013 as foliar sprays (250 treatments, 39 a.i) or soil applications (47 treatments, 9 a.i) to control D. citri in citrus. A combined effect of nymphal and adult suppression in response to sprays of 23 insecticides representing 9 modes of action (MoA) groups and 3 unknown MoA provided more than 90% reduction of adult D. citri over 24–68 days. Observable effects on nymphs were generally of shorter duration due to rapid maturation of flush. However, reduction of 76–100% nymphs or adults over 99–296 days was seen on young trees receiving drenches of the neonicotinoids imidacloprid, thiamethoxam or clothianidin (MoA 4A) and a novel anthranilic diamide, cyantraniliprole (MoA 28). Effective products identified for foliar sprays to control D. citri provide sufficient MoA groups for rotation to delay evolution of insecticide resistance by D. citri and other pests. However, cyantraniliprole is now the only available alternative for rotation with neonicotinoids in soil application to young trees. Sprays of up to eight of the most effective insecticides could be rotated over a year without repetition of any MoA and little or no recourse to neonicotinoids or cyantraniliprole, so important for protection of young trees. Other considerations effecting decisions of what and when to spray include prevalence of huanglongbing, pest pressure, pre-harvest intervals, overall budget, equipment availability, and conservation of beneficial arthropods. Examples of spray programs utilizing broad-spectrum and relatively selective insecticides are provided to improve vector management and may vary

  3. Differences in Stylet Sheath Occurrence and the Fibrous Ring (Sclerenchyma) between xCitroncirus Plants Relatively Resistant or Susceptible to Adults of the Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae)

    PubMed Central

    Ammar, El-Desouky; Richardson, Matthew L.; Abdo, Zaid; Hall, David G.; Shatters, Robert G.

    2014-01-01

    The Asian citrus psyllid (ACP, Diaphorina citri, Hemiptera: Liviidae), is the principal vector of the phloem-limited bacteria strongly associated with huanglongbing (HLB), the world’s most serious disease of citrus. Host plant resistance may provide an environmentally safe and sustainable method of controlling ACP and/or HLB. Two xCitroncirus accessions (hybrids of Poncirus trifoliata and Citrus spp.), that are relatively resistant (UN-3881) or relatively susceptible (Troyer-1459) to ACP adults with regard to adult longevity, were compared in relation to ACP feeding behavior and some structural features of the leaf midrib. The settling (putative feeding/probing) sites of ACP adults on various parts of the leaf were not influenced primarily by plant accession. However, fewer ACP stylet sheaths were found in the midrib and fewer stylet sheath termini reached the vascular bundle (phloem and/or xylem) in UN-3881 compared to Troyer-1459 plants. Furthermore, in midribs of UN-3881 leaves the fibrous ring (sclerenchyma) around the phloem was significantly wider (thicker) compared to that in midribs of Troyer-1459 leaves. Our data indicate that feeding and/or probing by ACP adults into the vascular bundle is less frequent in the more resistant (UN-3881) than in the more susceptible (Troyer-1459) accessions. Our results also suggest that the thickness of the fibrous ring may be a barrier to stylet penetration into the vascular bundle, which is important for successful ACP feeding on the phloem and for transmitting HLB-associated bacteria. These results may help in the development of citrus plants resistant to ACP, which in turn could halt or slow the spread of the HLB-associated bacteria by this vector. PMID:25343712

  4. Differences in stylet sheath occurrence and the fibrous ring (sclerenchyma) between xCitroncirus plants relatively resistant or susceptible to adults of the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae).

    PubMed

    Ammar, El-Desouky; Richardson, Matthew L; Abdo, Zaid; Hall, David G; Shatters, Robert G

    2014-01-01

    The Asian citrus psyllid (ACP, Diaphorina citri, Hemiptera: Liviidae), is the principal vector of the phloem-limited bacteria strongly associated with huanglongbing (HLB), the world's most serious disease of citrus. Host plant resistance may provide an environmentally safe and sustainable method of controlling ACP and/or HLB. Two xCitroncirus accessions (hybrids of Poncirus trifoliata and Citrus spp.), that are relatively resistant (UN-3881) or relatively susceptible (Troyer-1459) to ACP adults with regard to adult longevity, were compared in relation to ACP feeding behavior and some structural features of the leaf midrib. The settling (putative feeding/probing) sites of ACP adults on various parts of the leaf were not influenced primarily by plant accession. However, fewer ACP stylet sheaths were found in the midrib and fewer stylet sheath termini reached the vascular bundle (phloem and/or xylem) in UN-3881 compared to Troyer-1459 plants. Furthermore, in midribs of UN-3881 leaves the fibrous ring (sclerenchyma) around the phloem was significantly wider (thicker) compared to that in midribs of Troyer-1459 leaves. Our data indicate that feeding and/or probing by ACP adults into the vascular bundle is less frequent in the more resistant (UN-3881) than in the more susceptible (Troyer-1459) accessions. Our results also suggest that the thickness of the fibrous ring may be a barrier to stylet penetration into the vascular bundle, which is important for successful ACP feeding on the phloem and for transmitting HLB-associated bacteria. These results may help in the development of citrus plants resistant to ACP, which in turn could halt or slow the spread of the HLB-associated bacteria by this vector. PMID:25343712

  5. Survey of Endosymbionts in the Diaphorina citri Metagenome and Assembly of a Wolbachia wDi Draft Genome

    PubMed Central

    Saha, Surya; Hunter, Wayne B.; Reese, Justin; Morgan, J. Kent; Marutani-Hert, Mizuri; Huang, Hong; Lindeberg, Magdalen

    2012-01-01

    Diaphorina citri (Hemiptera: Psyllidae), the Asian citrus psyllid, is the insect vector of Ca. Liberibacter asiaticus, the causal agent of citrus greening disease. Sequencing of the D. citri metagenome has been initiated to gain better understanding of the biology of this organism and the potential roles of its bacterial endosymbionts. To corroborate candidate endosymbionts previously identified by rDNA amplification, raw reads from the D. citri metagenome sequence were mapped to reference genome sequences. Results of the read mapping provided the most support for Wolbachia and an enteric bacterium most similar to Salmonella. Wolbachia-derived reads were extracted using the complete genome sequences for four Wolbachia strains. Reads were assembled into a draft genome sequence, and the annotation assessed for the presence of features potentially involved in host interaction. Genome alignment with the complete sequences reveals membership of Wolbachia wDi in supergroup B, further supported by phylogenetic analysis of FtsZ. FtsZ and Wsp phylogenies additionally indicate that the Wolbachia strain in the Florida D. citri isolate falls into a sub-clade of supergroup B, distinct from Wolbachia present in Chinese D. citri isolates, supporting the hypothesis that the D. citri introduced into Florida did not originate from China. PMID:23166822

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

    PubMed

    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. PMID:24620723

  7. Geographic Distribution of Habitat, Development, and Population Growth Rates of the Asian Citrus Psyllid, Diaphorina citri, in Mexico

    PubMed Central

    López-Collado, José; Isabel López-Arroyo, J.; Robles-García, Pedro L.; Márquez-Santos, Magdalena

    2013-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an introduced pest in Mexico and a vector of huanglongbing, a lethal citrus disease. Estimations of the habitat distribution and population growth rates of D. citri are required to establish regional and areawide management strategies and can be used as a pest risk analysis tools. In this study, the habitat distribution of D. citri in Mexico was computed with MaxEnt, an inductive, machine-learning program that uses bioclimatic layers and point location data. Geographic distributions of development and population growth rates were determined by fitting a temperature-dependent, nonlinear model and projecting the rates over the target area, using the annual mean temperature as the predictor variable. The results showed that the most suitable regions for habitat of D. citri comprise the Gulf of Mexico states, Yucatán Peninsula, and areas scattered throughout the Pacific coastal states. Less suitable areas occurred in northern and central states. The most important predictor variables were related to temperature. Development and growth rates had a distribution wider than habitat, reaching some of the northern states of México. Habitat, development, and population growth rates were correlated to each other and with the citrus producing area. These relationships indicated that citrus producing states are within the most suitable regions for the occurrence, development, and population growth of D. citri, therefore increasing the risk of huanglongbing dispersion. PMID:24735280

  8. Exposure to Guava Affects Citrus Olfactory Cues and Attractiveness to Diaphorina citri (Hemiptera: Psyllidae).

    PubMed

    Barman, Jagadish Chandra; Campbell, Stuart A; Zeng, Xinnian

    2016-06-01

    Intercropping can reduce agricultural pest incidence, and represents an important sustainable alternative to conventional pest control methods. Understanding the ecological mechanisms for intercropping could help optimize its use, particularly in tropical systems which present a large number of intercropping possibilities. Citrus is threatened worldwide by greening disease (huanglongbing, HLB) vectored by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). Control of HLB and citrus psyllid can be partially achieved through intercropping with guava, Psidium guajava L., but the mechanisms remain unclear. We tested the hypothesis that guava olfactory cues affect psyllid behavior by altering the attractiveness of citrus through plant-plant interactions. In choice and no-choice cage experiments, psyllid settlement was reduced on citrus shoots that had been exposed to guava shoot odors for at least 2 h. In Y-tube olfactometer experiments, psyllids oriented to odors of unexposed, compared with guava-exposed, citrus shoots. These behavioral results indicate that a mechanism for the success of guava intercropping for sustainable, ecological disease management may be the indirect effect of guava on citrus attractiveness. PMID:27247354

  9. Resistance of Citrus and Related Genera to Diaphorina citri Kuwayama (Hemiptera: Liviidae).

    PubMed

    Borgoni, P C; Vendramim, J D; Lourencão, A L; Machado, M A

    2014-10-01

    The present study was developed to evaluate the resistance of the following genotypes of Citrus and related genera to this pest: 'Pera,' 'Natal', and 'Washington Navel' oranges (Citrus sinensis), 'Marsh Seedless' grapefruit (Citrus paradisi), hardy orange 'Rubidoux' (Poncirus trifoliata), kumquat (Fortunella margarita Swingle), citrumelo 'Swingle' (C. paradisi x P. trifoliata), and citrange 'Troyer' (P. trifoliata x C. sinensis). The experiments were performed in greenhouses with plants grafted onto 'Rangpur' lime (Citrus limonia) and placed individually in voile cages. The preference for oviposition in a no-choice test, and the effect of genotype were evaluated. The egg-adult cycle was monitored to determine the effect of genotype on the biology of the insect. Poncirus 'Rubidoux' was the least preferred genotype for oviposition; reduced number of eggs was also found to occur on citrange 'Troyer', and 'Marsh Seedless' was the genotype with the most eggs. No significant variation in the duration of the embryonic period was observed; however, a difference in the viability of eggs was found, with the lowest egg viabilities on 'Swingle.' Kumquat and 'Marsh Seedless' genotypes were correlated with increased durations of the nymphal phase, however, there was no difference in the survival of this phase. Fecundity of females on 'Troyer', 'Swingle', and kumquat was reduced. Considering all of the evaluated parameters, it was concluded that cultivars of sweet orange are the most susceptible genotypes to Diaphorina citri. Regarding oviposition, P. trifoliata 'Rubidoux' showed resistance of the antixenosis type. PMID:27193957

  10. Species clarification of Isaria isolates used as biocontrol agents against Diaphorina citri (Hemiptera: Liviidae) in Mexico.

    PubMed

    Gallou, Adrien; Serna-Domínguez, María G; Berlanga-Padilla, Angélica M; Ayala-Zermeño, Miguel A; Mellín-Rosas, Marco A; Montesinos-Matías, Roberto; Arredondo-Bernal, Hugo C

    2016-03-01

    Entomopathogenic fungi belonging to the genus Isaria (Hypocreales: Cordycipitaceae) are promising candidates for microbial control of insect pests. Currently, the Mexican government is developing a biological control program based on extensive application of Isaria isolates against Diaphorina citri (Hemiptera: Liviidae), a vector of citrus huanglongbing disease. Previous research identified three promising Isaria isolates (CHE-CNRCB 303, 305, and 307; tentatively identified as Isaria fumosorosea) from Mexico. The goal of this work was to obtain a complete morphological and molecular characterization of these isolates. Comparative analysis of morphology established that the isolates showed similar characteristics to Isaria javanica. Multi-gene analysis confirmed the morphological identification by including the three isolates within the I. javanica clade. Additionally, this work demonstrated the misidentifications of three other Isaria isolates (CHE-CNRCB 310 and 324: I. javanica, formerly I. fumosorosea; CHE-CNRCB 393: I. fumosorosea, formerly Isaria farinosa), underlying the need for a full and correct characterization of an isolate before developing a biological control program. Finally, the inter-simple sequence repeat (ISSR) genotyping method revealed that the CHE-CNRCB 303, 305, and 307 isolates belong to three different genotypes. This result indicates that ISSR markers could be used as a tool to monitor their presence in field conditions. PMID:26895870

  11. Detection of citrus huanglongbing-associated ‘Candidatus Liberibacter asiaticus’ in citrus and Diaphorina citri in Pakistan, season variability, and implications for disease management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report the detection of the huanglongbing (HLB)-associated bacterium ‘Candidatus Liberibacter asiaticus’ from both plants and insects in Pakistan and the seasonal variability in the numbers of ‘Ca. L. asiaticus’-positive psyllid vector, Diaphorina citri. Our studies showed that ‘Ca. L. asiaticus’...

  12. RNAi-based strategy for Asian citrus psyllid (Diaphorina citri) Control: A method to reduce the spread of citrus greening disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus greening disease is a serious bacterial disease of citrus worldwide and is vectored by the Asian citrus pysllid (Diaphorina Citri). The only effective control strategy includes vigorous control of the psyllid, primarily through heavy reliance on pesticides. As a more sustainable and environm...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  14. The roles of olfactory cues, visual cues, and mating status in orientation of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) to four different host plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is an important worldwide pest of citrus that vectors three phloem-restricted bacteria in the genus Candidatus Liberibacter, the causative agents of huanglongbing (citrus greening disease). We examined the behavioral responses of mated and unmated D. ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  16. A rapid field detection system for citrus huanglongbing associated ‘Candidatus Liberibacter asiaticus’ from the psyllid vector, diaphorina citri kuwayama and its implications in disease management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report the development of an affordable detection kit for the detection of ‘Candidatus Liberibacter asiaticus’ (Las) from the psyllid vector, Diaphorina citri, which can provide real time test results in the field or field laboratory within 30-40 minutes without the need for expensive laboratory ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  18. Nested PCR is essential for the detection of extremely low titer of Candidatus Liberibacter asiaticus from citrus and its vector psyllid Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB), transmitted by the psyllids Diaphorina citri and Trioza erytreae, is one of the most devastating diseases of citrus worldwide. The disease is associated with three different species of Candidatus Liberibacter: Ca. L. asiaticus (Las), Ca. L. americanus and Ca. L. africanu...

  19. Ultrastructure and development of the new stylets inside pre-molting first instar nymphs of the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ultrastructure and development of new stylets was studied in pre-molting first instar nymph of Diaphorina citri. Two oval-shaped masses of cuboidal hypodermal cells, located in the cephalic region, had long extensions that ended with developing pairs of mandibular and maxillary stylets, apparent...

  20. Detection and relative titer of Candidatus Liberibacter asiaticus in the salivary glands and alimentary canal of Diaphorina citri (Hemiptera: Psyllidae) vector of citrus Huanglongbing disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Candidatus Liberibacter asiaticus has been strongly implicated as the causative agent of huanglongbing (HLB), or citrus greening, which is currently the most devastating citrus disease worldwide. In the Americas and Asia, HLB is transmitted by the Asian citrus psyllid Diaphorina citri in a persisten...

  1. Localization of Candidatus liberibacter asiaticus associated with huanglongbing disease in various organs of its insect vector Diaphorina citri using FISH and Q-PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Candidatus Liberibacter asiaticus (Las) has been associated with huanglongbing (HLB), or citrus greening, which is currently the most devastating citrus disease in many areas of the world. HLB is transmitted in Florida by the Asian citrus psyllid Diaphorina citri (Hemiptera, Psyllidae) in a persiste...

  2. Antennal and Abdominal Transcriptomes Reveal Chemosensory Genes in the Asian Citrus Psyllid, Diaphorina citri

    PubMed Central

    Wu, Zhongzhen; Zhang, He; Bin, Shuying; Chen, Lei; Han, Qunxin; Lin, Jintian

    2016-01-01

    The Asian citrus psyllid, Diaphorina citri is the principal vector of the highly destructive citrus disease called Huanglongbing (HLB) or citrus greening, which is a major threat to citrus cultivation worldwide. More effective pest control strategies against this pest entail the identification of potential chemosensory proteins that could be used in the development of attractants or repellents. However, the molecular basis of olfaction in the Asian citrus psyllid is not completely understood. Therefore, we performed this study to analyze the antennal and abdominal transcriptome of the Asian citrus psyllid. We identified a large number of transcripts belonging to nine chemoreception-related gene families and compared their expression in male and female adult antennae and terminal abdomen. In total, 9 odorant binding proteins (OBPs), 12 chemosensory proteins (CSPs), 46 odorant receptors (ORs), 20 gustatory receptors (GRs), 35 ionotropic receptors (IRs), 4 sensory neuron membrane proteins (SNMPs) and 4 different gene families encoding odorant-degrading enzymes (ODEs): 80 cytochrome P450s (CYPs), 12 esterase (ESTs), and 5 aldehyde dehydrogenases (ADE) were annotated in the D. citri antennal and abdominal transcriptomes. Our results revealed that a large proportion of chemosensory genes exhibited no distinct differences in their expression patterns in the antennae and terminal abdominal tissues. Notably, RNA sequencing (RNA-seq) data and quantitative real time-PCR (qPCR) analyses showed that 4 DictOBPs, 4 DictCSPs, 4 DictIRs, 1 DictSNMP, and 2 DictCYPs were upregulated in the antennae relative to that in terminal abdominal tissues. Furthermore, 2 DictOBPs (DictOBP8 and DictOBP9), 2 DictCSPs (DictOBP8 and DictOBP12), 4 DictIRs (DictIR3, DictIR6, DictIR10, and DictIR35), and 1 DictCYP (DictCYP57) were expressed at higher levels in the male antennae than in the female antennae. Our study provides the first insights into the molecular basis of chemoreception in this insect

  3. Antennal and Abdominal Transcriptomes Reveal Chemosensory Genes in the Asian Citrus Psyllid, Diaphorina citri.

    PubMed

    Wu, Zhongzhen; Zhang, He; Bin, Shuying; Chen, Lei; Han, Qunxin; Lin, Jintian

    2016-01-01

    The Asian citrus psyllid, Diaphorina citri is the principal vector of the highly destructive citrus disease called Huanglongbing (HLB) or citrus greening, which is a major threat to citrus cultivation worldwide. More effective pest control strategies against this pest entail the identification of potential chemosensory proteins that could be used in the development of attractants or repellents. However, the molecular basis of olfaction in the Asian citrus psyllid is not completely understood. Therefore, we performed this study to analyze the antennal and abdominal transcriptome of the Asian citrus psyllid. We identified a large number of transcripts belonging to nine chemoreception-related gene families and compared their expression in male and female adult antennae and terminal abdomen. In total, 9 odorant binding proteins (OBPs), 12 chemosensory proteins (CSPs), 46 odorant receptors (ORs), 20 gustatory receptors (GRs), 35 ionotropic receptors (IRs), 4 sensory neuron membrane proteins (SNMPs) and 4 different gene families encoding odorant-degrading enzymes (ODEs): 80 cytochrome P450s (CYPs), 12 esterase (ESTs), and 5 aldehyde dehydrogenases (ADE) were annotated in the D. citri antennal and abdominal transcriptomes. Our results revealed that a large proportion of chemosensory genes exhibited no distinct differences in their expression patterns in the antennae and terminal abdominal tissues. Notably, RNA sequencing (RNA-seq) data and quantitative real time-PCR (qPCR) analyses showed that 4 DictOBPs, 4 DictCSPs, 4 DictIRs, 1 DictSNMP, and 2 DictCYPs were upregulated in the antennae relative to that in terminal abdominal tissues. Furthermore, 2 DictOBPs (DictOBP8 and DictOBP9), 2 DictCSPs (DictOBP8 and DictOBP12), 4 DictIRs (DictIR3, DictIR6, DictIR10, and DictIR35), and 1 DictCYP (DictCYP57) were expressed at higher levels in the male antennae than in the female antennae. Our study provides the first insights into the molecular basis of chemoreception in this insect

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

    PubMed Central

    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

  5. Characterization of the Relative Abundance of the Citrus Pathogen Ca. Liberibacter Asiaticus in the Microbiome of Its Insect Vector, Diaphorina citri, using High Throughput 16S rRNA Sequencing

    PubMed Central

    Fagen, Jennie R; Giongo, Adriana; Brown, Christopher T; Davis-Richardson, Austin G; Gano, Kelsey A; Triplett, Eric W

    2012-01-01

    The relationship between the causal agent of Huanglongbing (HLB), Ca. Liberibacter asiaticus(Las), and the naturally occurring endosymbiotic community of its insect vector, the Asian citrus psyllid (ACP), Diaphorina citri, was studied. Variation was observed in the titer of Las within an ACP population feeding on the same material. The cause of this disparity is unknown, and has implications for Las transmission and the spread of HLB. This study utilizes culture independent methods to establish the relationship between the ACP’s microbial community and Las acquisition. DNA from 21 psyllids was amplified using universal 16S rRNA primers with Illumina adaptor regions and a sample-specific 7- base identifier. These amplicons were then batch-sequenced on the Illumina platform. The resulting sequences were separated by the identifier, and compared to known sequences in a 16S rRNA database. The microbial communities of each psyllid were compared to determine whether a correlation exists between the ACP’s endosymbionts and level of Las acquisition. ACPs were dominated by the same four bacterialgenera regardless of the abundance of Ca.Liberibacter. A combination of qPCR and Illumina sequencing was used to establish an infection gradient among the sampled ACPs. The Ca. Liberibacter titer within the insect was found to have a strong negative relationship with an endosymbiont residing in the syncytium of the mycetocyte and a positive relationship with Wolbachia. These correlations have implications in the acquisition of Las by the ACP as well as the activities of Las within this vector. PMID:22529882

  6. An evaluation of different plant genotypes for rearing Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psylloidea)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP) is the vector of bacteria responsible for a serious citrus disease known as huanglongbing (also known as citrus greening disease). Many research endeavors on ACP are dependent on a steady supply of ACP, which can be facilitated using a laboratory or greenhouse colony m...

  7. Lethal and Sublethal Impacts of Acaricides on Tamarixia radiata (Hemiptera: Eulophidae), an Important Ectoparasitoid of Diaphorina citri (Hemiptera: Liviidae).

    PubMed

    Lira, A C S; Zanardi, O Z; Beloti, V H; Bordini, G P; Yamamoto, P T; Parra, J R P; Carvalho, G A

    2015-10-01

    The use of synthetic acaricides for management of pest mites may alter the efficacy of the ectoparasitoid Tamarixia radiata (Waterston) in biological control of Diaphorina citri Kuwayama, the vector of the bacteria associated with huanglongbing (HLB) in citrus orchards. We evaluated the toxicity of 16 acaricides that are recommended for the control of citrus-pest mites to T. radiata. Acrinathrin, bifenthrin, carbosulfan, and fenpropathrin caused high acute toxicity and were considered harmful (mortality >77%) to T. radiata. Abamectin, diflubenzuron, etoxazole, fenbutatin oxide, fenpyroximate, flufenoxuron, hexythiazox, propargite, spirodiclofen, and sulfur caused low acute toxicity and affected the parasitism rate and emergence rate of adults (F1 generation), and were considered slightly harmful to T. radiata. Dicofol and pyridaben did not affect the survival and action of the ectoparasitoid, and were considered harmless. In addition to its acute toxicity, carbosulfan caused mortality higher than 25% for >30 d after application, and was considered persistent. Acrinathrin, bifenthrin, fenpropathrin, fenpyroximate, propargite, and sulfur caused mortalities over 25% until 24 d after application and were considered moderately persistent; abamectin was slightly persistent, and fenbutatin oxide was short lived. Our results suggest that most acaricides used to control pest mites in citrus affect the density and efficacy of T. radiata in the biological control of D. citri. However, further evaluations are needed in order to determine the effect of these products on this ectoparasitoid under field conditions. PMID:26453716

  8. Characterization of a Recombinant Cathepsin B-Like Cysteine Peptidase from Diaphorina citri Kuwayama (Hemiptera: Liviidae): A Putative Target for Control of Citrus Huanglongbing.

    PubMed

    Ferrara, Taíse Fernanda da Silva; Schneider, Vanessa Karine; Kishi, Luciano Takeshi; Carmona, Adriana Karaoglanovic; Alves, Marcio Fernando Madureira; Belasque-Júnior, Jose; Rosa, José César; Hunter, Wayne Brian; Henrique-Silva, Flávio; Soares-Costa, Andrea

    2015-01-01

    Huanglonbing (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) and the psyllid Diaphorina citri, vector of disease, that transmits the bacterium associated with HLB. The control of disease can be achieved by suppressing either the bacterium or the vector. Among the control strategies for HLB disease, one of the widely used consists in controlling the enzymes of the disease vector, Diaphorina citri. The insect Diaphorina citri belongs to the order Hemiptera, which frequently have cysteine peptidases in the gut. The importance of this class of enzymes led us to search for enzymes in the D. citri transcriptome for the establishment of alternatives strategies for HLB control. In this study, we reported the identification and characterization of a cathepsin B-like cysteine peptidase from D. citri (DCcathB). DCcathB was recombinantly expressed in Pichia pastoris, presenting a molecular mass of approximately 50 kDa. The enzyme hydrolyzed the fluorogenic substrate Z-F-R-AMC (Km = 23.5 μM) and the selective substrate for cathepsin B, Z-R-R-AMC (Km = 6.13 μM). The recombinant enzyme was inhibited by the cysteine protease inhibitors E64 (IC50 = 0.014 μM) and CaneCPI-4 (Ki = 0.05 nM) and by the selective cathepsin B inhibitor CA-074 (IC50 = 0.095 nM). RT-qPCR analysis revealed that the expression of the DCcathB in nymph and adult was approximately 9-fold greater than in egg. Moreover, the expression of this enzyme in the gut was 175-fold and 3333-fold higher than in the remaining tissues and in the head, respectively, suggesting that DCcathB can be a target for HLB control. PMID:26717484

  9. Characterization of a Recombinant Cathepsin B-Like Cysteine Peptidase from Diaphorina citri Kuwayama (Hemiptera: Liviidae): A Putative Target for Control of Citrus Huanglongbing

    PubMed Central

    Kishi, Luciano Takeshi; Carmona, Adriana Karaoglanovic; Alves, Marcio Fernando Madureira; Belasque-Júnior, Jose; Rosa, José César; Hunter, Wayne Brian; Henrique-Silva, Flávio; Soares-Costa, Andrea

    2015-01-01

    Huanglonbing (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) and the psyllid Diaphorina citri, vector of disease, that transmits the bacterium associated with HLB. The control of disease can be achieved by suppressing either the bacterium or the vector. Among the control strategies for HLB disease, one of the widely used consists in controlling the enzymes of the disease vector, Diaphorina citri. The insect Diaphorina citri belongs to the order Hemiptera, which frequently have cysteine peptidases in the gut. The importance of this class of enzymes led us to search for enzymes in the D. citri transcriptome for the establishment of alternatives strategies for HLB control. In this study, we reported the identification and characterization of a cathepsin B-like cysteine peptidase from D. citri (DCcathB). DCcathB was recombinantly expressed in Pichia pastoris, presenting a molecular mass of approximately 50 kDa. The enzyme hydrolyzed the fluorogenic substrate Z-F-R-AMC (Km = 23.5 μM) and the selective substrate for cathepsin B, Z-R-R-AMC (Km = 6.13 μM). The recombinant enzyme was inhibited by the cysteine protease inhibitors E64 (IC50 = 0.014 μM) and CaneCPI-4 (Ki = 0.05 nM) and by the selective cathepsin B inhibitor CA-074 (IC50 = 0.095 nM). RT-qPCR analysis revealed that the expression of the DCcathB in nymph and adult was approximately 9-fold greater than in egg. Moreover, the expression of this enzyme in the gut was 175-fold and 3333-fold higher than in the remaining tissues and in the head, respectively, suggesting that DCcathB can be a target for HLB control. PMID:26717484

  10. Citrus tristeza virus-based RNAi in citrus plants induces gene silencing in Diaphorina citri, a phloem-sap sucking insect vector of citrus greening disease (Huanglongbing).

    PubMed

    Hajeri, Subhas; Killiny, Nabil; El-Mohtar, Choaa; Dawson, William O; Gowda, Siddarame

    2014-04-20

    A transient expression vector based on Citrus tristeza virus (CTV) is unusually stable. Because of its stability it is being considered for use in the field to control Huanglongbing (HLB), which is caused by Candidatus Liberibacter asiaticus (CLas) and vectored by Asian citrus psyllid, Diaphorina citri. In the absence of effective control strategies for CLas, emphasis has been on control of D. citri. Coincident cohabitation in phloem tissue by CLas, D. citri and CTV was exploited to develop a novel method to mitigate HLB through RNA interference (RNAi). Since CTV has three RNA silencing suppressors, it was not known if CTV-based vector could induce RNAi in citrus. Yet, expression of sequences targeting citrus phytoene desaturase gene by CTV-RNAi resulted in photo-bleaching phenotype. CTV-RNAi vector, engineered with truncated abnormal wing disc (Awd) gene of D. citri, induced altered Awd expression when silencing triggers ingested by feeding D. citri nymphs. Decreased Awd in nymphs resulted in malformed-wing phenotype in adults and increased adult mortality. This impaired ability of D. citri to fly would potentially limit the successful vectoring of CLas bacteria between citrus trees in the grove. CTV-RNAi vector would be relevant for fast-track screening of candidate sequences for RNAi-mediated pest control. PMID:24572372

  11. Double-Stranded RNA Uptake through Topical Application, Mediates Silencing of Five CYP4 Genes and Suppresses Insecticide Resistance in Diaphorina citri

    PubMed Central

    Killiny, Nabil; Hajeri, Subhas; Tiwari, Siddharth; Gowda, Siddarame; Stelinski, Lukasz L.

    2014-01-01

    Silencing of genes through RNA interference (RNAi) in insects has gained momentum during the past few years. RNAi has been used to cause insect mortality, inhibit insect growth, increase insecticide susceptibility, and prevent the development of insecticide resistance. We investigated the efficacy of topically applied dsRNA to induce RNAi for five Cytochrome P450 genes family 4 (CYP4) in Diaphorina citri. We previously reported that these CYP4 genes are associated with the development of insecticide resistance in D. citri. We targeted five CYP4 genes that share a consensus sequence with one dsRNA construct. Quantitative PCR confirmed suppressed expression of the five CYP4 genes as a result of dsRNA topically applied to the thoracic region of D. citri when compared to the expression levels in a control group. Western blot analysis indicated a reduced signal of cytochrome P450 proteins (45 kDa) in adult D. citri treated with the dsRNA. In addition, oxidase activity and insecticide resistance were reduced for D. citri treated with dsRNA that targeted specific CYP4 genes. Mortality was significantly higher in adults treated with dsRNA than in adults treated with water. Our results indicate that topically applied dsRNA can penetrate the cuticle of D. citri and induce RNAi. These results broaden the scope of RNAi as a mechanism to manage pests by targeting a broad range of genes. The results also support the application of RNAi as a viable tool to overcome insecticide resistance development in D. citri populations. However, further research is needed to develop grower-friendly delivery systems for the application of dsRNA under field conditions. Considering the high specificity of dsRNA, this tool can also be used for management of D. citri by targeting physiologically critical genes involved in growth and development. PMID:25330026

  12. Double-stranded RNA uptake through topical application, mediates silencing of five CYP4 genes and suppresses insecticide resistance in Diaphorina citri.

    PubMed

    Killiny, Nabil; Hajeri, Subhas; Tiwari, Siddharth; Gowda, Siddarame; Stelinski, Lukasz L

    2014-01-01

    Silencing of genes through RNA interference (RNAi) in insects has gained momentum during the past few years. RNAi has been used to cause insect mortality, inhibit insect growth, increase insecticide susceptibility, and prevent the development of insecticide resistance. We investigated the efficacy of topically applied dsRNA to induce RNAi for five Cytochrome P450 genes family 4 (CYP4) in Diaphorina citri. We previously reported that these CYP4 genes are associated with the development of insecticide resistance in D. citri. We targeted five CYP4 genes that share a consensus sequence with one dsRNA construct. Quantitative PCR confirmed suppressed expression of the five CYP4 genes as a result of dsRNA topically applied to the thoracic region of D. citri when compared to the expression levels in a control group. Western blot analysis indicated a reduced signal of cytochrome P450 proteins (45 kDa) in adult D. citri treated with the dsRNA. In addition, oxidase activity and insecticide resistance were reduced for D. citri treated with dsRNA that targeted specific CYP4 genes. Mortality was significantly higher in adults treated with dsRNA than in adults treated with water. Our results indicate that topically applied dsRNA can penetrate the cuticle of D. citri and induce RNAi. These results broaden the scope of RNAi as a mechanism to manage pests by targeting a broad range of genes. The results also support the application of RNAi as a viable tool to overcome insecticide resistance development in D. citri populations. However, further research is needed to develop grower-friendly delivery systems for the application of dsRNA under field conditions. Considering the high specificity of dsRNA, this tool can also be used for management of D. citri by targeting physiologically critical genes involved in growth and development. PMID:25330026

  13. Unreliable pesticide control of the vector psyllid Diaphorina citri (Hemiptera: Psyllidae) for the reduction of microorganism disease transmission.

    PubMed

    Ichinose, Katsuya; Miyazi, Kastuhiko; Matsuhira, Kunihiko; Yasuda, Keiji; Sadoyama, Yasutsune; Do, Hong Tuan; Doan, Van Bang

    2010-07-01

    Systemic insecticides and application methods were examined for the control of the vector psyllid of citrus greening disease, Diaphorina citri, on grown king mandarin trees in an orchard in southern Vietnam from May 2007 to September 2008. Leaf spraying of imidacloprid, thiamethoxam, and clothianidin attained about 50 % to 70 % mortality of the psyllid for one month after the application and showed decreased efficacy thereafter. Imidacloprid was more effective than the other two insecticides, but the efficacy on grown trees was still much lower than that following application to young seedlings. Trunk injection of these insecticides accomplished similar mortality, about 50 %, and the efficacy of the insecticides continued for one month. An adjuvant was used with the goal of protecting the insecticide applied on leaves from precipitation, and mineral oil was used for the same reason, as well as its potential to control the psyllid. Neither the adjuvant nor the mineral oil played an evident role in the increase of insecticide efficacy or longevity. Application of systemic insecticides at even 50 times the dose described above did not show an apparent increase in psyllid mortality. The insecticides commonly used for the control of the psyllid were not as effective on this insect on grown trees as we had expected they would be. PMID:20512737

  14. Host Range Testing of Diaphorencyrtus aligarhensis (Hymenoptera: Encyrtidae) for Use in Classical Biological Control of Diaphorina citri (Hemiptera: Liviidae) in California.

    PubMed

    Bistline-East, Allison; Pandey, Raju; Kececi, Mehmet; Hoddle, Mark S

    2015-06-01

    Host range tests for Diaphorencyrtus aligarhensis (Shafee, Alam, & Agarwal) (Hymenoptera: Encyrtidae), an endoparasitoid of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), sourced from Punjab Pakistan, were conducted in quarantine at the University of California, Riverside, CA. Seven nontarget psyllid species representing four psyllid families were exposed to mated D. aligarhensis females in four different treatment types: 1) short sequential no-choice treatments, 2) prolonged sequential no-choice treatments, 3) prolonged no-choice static treatments, and 4) choice treatments. Selection of nontarget psyllid species was based on phylogenetic proximity to D. citri, likelihood of being encountered by D. aligarhensis in the prospective release areas in California, and psyllid species in biological control of invasive weeds. D. aligarhensis exhibited high host affinity to D. citri, and only parasitized one nontarget species, the pestiferous potato psyllid, Bactericera cockerelli (Sulc), at low levels (<14%). Based on the results of this study, we conclude that D. aligarhensis has a narrow host range and exhibits a high level of host specificity, as it shows a significant attack preference for the target pest, D. citri. Results presented here suggest D. aligarhensis poses minimal risk to nontarget psyllid species in California. PMID:26470214

  15. Effect of UV-Blocking Plastic Films on Take-Off and Host Plant Finding Ability of Diaphorina citri (Hemiptera: Liviidae).

    PubMed

    Miranda, M P; Dos Santos, F L; Felippe, M R; Moreno, A; Fereres, A

    2015-02-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a major pest of citrus worldwide due to its ability to transmit the bacteria associated with huanglongbing. Vision, behavior, and performance of insect pests can be manipulated by using ultraviolet (UV)-blocking materials. Thus, the aim of our study was to evaluate how UV-blocking plastic films may affect the take-off and host plant finding ability of D. citri. To assess the effect of a UV-deficient environment on take-off, adult psyllids were released from a vial inside a screenhouse covered by a UV-blocking or standard (control) film and the number of insects remaining on each vial under each treatment was counted at different time intervals. Moreover, to assess the ability of D. citri to find citrus plants under a UV-deficient environment, two independent no-choice host plant finding assays with different plant arrangements were conducted. In each treatment, the number of psyllids per plant at different time intervals was counted. Both D. citri take-off and host plant finding ability was clearly disrupted under a UV-deficient environment. The number of psyllids remaining in the vials was significantly higher under UV-blocking than standard film in all periods recorded. Furthermore, psyllids were present in significantly higher number on citrus plants under standard film than under UV-blocking film in all of the periods assessed and experiments conducted. Our results showed that UV-blocking materials could become a valuable strategy for integrated management of D. citri and huanglongbing in citrus grown in enclosed environments. PMID:26470126

  16. Impacts of Horticultural Mineral Oils and Two Insecticide Practices on Population Fluctuation of Diaphorina citri and Spread of Huanglongbing in a Citrus Orchard in Sarawak

    PubMed Central

    Leong, Stephen Chan Teck; Abang, Fatimah; Beattie, Andrew; Kueh, Roland Jui Heng; Wong, Sing King

    2012-01-01

    Aspects of the incidence and spread of the citrus disease huanglongbing (HLB) in relation to the vector Diaphorina citri population fluctuation were studied from January 1999 to December 2001 seasons in a 0.8 ha citrus orchard at Jemukan (1° 33′N, 110° 41′E), Southwest Sarawak in Malaysia. In relation to insecticide and horticultural mineral oils (HMOs) use, levels of HLB infection rose quite rapidly over the next 3 years in the unsprayed control and less rapidly in the other treatments such as imidacloprid, nC24HMO, and triazophos/cypermethrin/chlorpyrifos. Levels of HLB as determined by Polymerase Chain Reaction (PCR) were 42.2%, 9.4%, 11.4%, and 22.7%, respectively. The effects of nC24HMO and conventional pesticides on the citrus psyllid population and parasitoids in citrus orchard were also determined. PMID:22629178

  17. Impacts of horticultural mineral oils and two insecticide practices on population fluctuation of Diaphorina citri and spread of Huanglongbing in a citrus orchard in Sarawak.

    PubMed

    Leong, Stephen Chan Teck; Abang, Fatimah; Beattie, Andrew; Kueh, Roland Jui Heng; Wong, Sing King

    2012-01-01

    Aspects of the incidence and spread of the citrus disease huanglongbing (HLB) in relation to the vector Diaphorina citri population fluctuation were studied from January 1999 to December 2001 seasons in a 0.8 ha citrus orchard at Jemukan (1° 33'N, 110° 41'E), Southwest Sarawak in Malaysia. In relation to insecticide and horticultural mineral oils (HMOs) use, levels of HLB infection rose quite rapidly over the next 3 years in the unsprayed control and less rapidly in the other treatments such as imidacloprid, nC24HMO, and triazophos/cypermethrin/chlorpyrifos. Levels of HLB as determined by Polymerase Chain Reaction (PCR) were 42.2%, 9.4%, 11.4%, and 22.7%, respectively. The effects of nC(24)HMO and conventional pesticides on the citrus psyllid population and parasitoids in citrus orchard were also determined. PMID:22629178

  18. Innate and Conditioned Responses to Chemosensory and Visual Cues in Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae), Vector of Huanglongbing Pathogens.

    PubMed

    Patt, Joseph M; Stockton, Dara; Meikle, William G; Sétamou, Mamoudou; Mafra-Neto, Agenor; Adamczyk, John J

    2014-01-01

    Asian citrus psyllid (Diaphorina citri) transmits Huanglongbing, a devastating disease that threatens citrus trees worldwide. A better understanding of the psyllid's host-plant selection process may lead to the development of more efficient means of monitoring it and predicting its movements. Since behavioral adaptations, such as associative learning, may facilitate recognition of suitable host-plants, we examined whether adult D. citri could be conditioned to visual and chemosensory stimuli from host and non-host-plant sources. Response was measured as the frequency of salivary sheaths, the residue of psyllid probing activity, in a line of emulsified wax on the surface of a test arena. The psyllids displayed both appetitive and aversive conditioning to two different chemosensory stimuli. They could also be conditioned to recognize a blue-colored probing substrate and their response to neutral visual cues was enhanced by chemosensory stimuli. Conditioned psyllids were sensitive to the proportion of chemosensory components present in binary mixtures. Naïve psyllids displayed strong to moderate innate biases to several of the test compounds. While innate responses are probably the psyllid's primary behavioral mechanism for selecting host-plants, conditioning may enhance its ability to select host-plants during seasonal transitions and dispersal. PMID:26462949

  19. Innate and Conditioned Responses to Chemosensory and Visual Cues in Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae), Vector of Huanglongbing Pathogens

    PubMed Central

    Patt, Joseph M.; Stockton, Dara; Meikle, William G.; Sétamou, Mamoudou; Mafra-Neto, Agenor; Adamczyk, John J.

    2014-01-01

    Asian citrus psyllid (Diaphorina citri) transmits Huanglongbing, a devastating disease that threatens citrus trees worldwide. A better understanding of the psyllid’s host-plant selection process may lead to the development of more efficient means of monitoring it and predicting its movements. Since behavioral adaptations, such as associative learning, may facilitate recognition of suitable host-plants, we examined whether adult D. citri could be conditioned to visual and chemosensory stimuli from host and non-host-plant sources. Response was measured as the frequency of salivary sheaths, the residue of psyllid probing activity, in a line of emulsified wax on the surface of a test arena. The psyllids displayed both appetitive and aversive conditioning to two different chemosensory stimuli. They could also be conditioned to recognize a blue-colored probing substrate and their response to neutral visual cues was enhanced by chemosensory stimuli. Conditioned psyllids were sensitive to the proportion of chemosensory components present in binary mixtures. Naïve psyllids displayed strong to moderate innate biases to several of the test compounds. While innate responses are probably the psyllid’s primary behavioral mechanism for selecting host-plants, conditioning may enhance its ability to select host-plants during seasonal transitions and dispersal. PMID:26462949

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

    PubMed

    Van Ekert, Evelien; Shatters, Robert G; Rougé, Pierre; Powell, Charles A; Smagghe, Guy; Borovsky, Dov

    2015-01-01

    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 JH biosynthesis in D. citri. A putative JH acid methyltransferase ortholog gene (jmtD) and its cognate cDNA were identified by searching D. citri genome database. Expression analysis shows expression in all life stages. In adults, it is expressed in the head-thorax, (containing the corpora allata), and the abdomen (containing ovaries and male accessory glands). A 3D protein model identified the catalytic groove with catalytically active amino acids and the S-adenosyl methionine (SAM)-binding loop. The cDNA was expressed in Escherichia coli cells and the purified enzyme showed high preference for farnesoic acid (FA) and homoFA (kcat of 0.752 × 10(-3) and 0.217 × 10(-3) s(-1), respectively) as compared to JH acid I (JHA I) (cis/trans/cis; 2Z, 6E, 10cis), JHA III (2E, 6E, 10cis), and JHA I (trans/cis/cis; 2E, 2Z, 10cis) (kcat of 0.081 × 10(-3), 0.013 × 10(-3), and 0.003 × 10(-3) s(-1), respectively). This suggests that this ortholog is a DcFA-o-methyl transferase gene (fmtD), not a jmtD, and that JH biosynthesis in D. citri proceeds from FA to JH III through methyl farnesoate (MF). DcFA-o-MT does not require Ca(2+), Mg(2+) or Zn(2+), however, Zn(2+) (1 mM) completely inhibits the enzyme probably by binding H115 at the active groove. This represents the first purified FA-o-MT from Hemiptera with preferred biological activity for FA and not JHA. PMID:25893162

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

    PubMed Central

    Van Ekert, Evelien; Shatters, Robert G.; Rougé, Pierre; Powell, Charles A.; Smagghe, Guy; Borovsky, Dov

    2015-01-01

    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 JH biosynthesis in D. citri. A putative JH acid methyltransferase ortholog gene (jmtD) and its cognate cDNA were identified by searching D. citri genome database. Expression analysis shows expression in all life stages. In adults, it is expressed in the head-thorax, (containing the corpora allata), and the abdomen (containing ovaries and male accessory glands). A 3D protein model identified the catalytic groove with catalytically active amino acids and the S-adenosyl methionine (SAM)-binding loop. The cDNA was expressed in Escherichia coli cells and the purified enzyme showed high preference for farnesoic acid (FA) and homoFA (kcat of 0.752 × 10−3 and 0.217 × 10−3 s−1, respectively) as compared to JH acid I (JHA I) (cis/trans/cis; 2Z, 6E, 10cis), JHA III (2E, 6E, 10cis), and JHA I (trans/cis/cis; 2E, 2Z, 10cis) (kcat of 0.081 × 10−3, 0.013 × 10−3, and 0.003 × 10−3 s−1, respectively). This suggests that this ortholog is a DcFA-o-methyl transferase gene (fmtD), not a jmtD, and that JH biosynthesis in D. citri proceeds from FA to JH III through methyl farnesoate (MF). DcFA-o-MT does not require Ca2+, Mg2+ or Zn2+, however, Zn2+ (1 mM) completely inhibits the enzyme probably by binding H115 at the active groove. This represents the first purified FA-o-MT from Hemiptera with preferred biological activity for FA and not JHA. PMID:25893162

  2. Essential Oil Variation from Twenty Two Genotypes of Citrus in Brazil-Chemometric Approach and Repellency Against Diaphorina citri Kuwayama.

    PubMed

    Andrade, Moacir Dos Santos; Ribeiro, Leandro do Prado; Borgoni, Paulo Cesar; Silva, Maria Fátima das Graças Fernandes da; Forim, Moacir Rossi; Fernandes, João Batista; Vieira, Paulo Cezar; Vendramin, José Djair; Machado, Marcos Antônio

    2016-01-01

    The chemical composition of volatile oils from 22 genotypes of Citrus and related genera was poorly differentiated, but chemometric techniques have clarified the relationships between the 22 genotypes, and allowed us to understand their resistance to D. citri. The most convincing similarities include the synthesis of (Z)-β-ocimene and (E)-caryophyllene for all 11 genotypes of group A. Genotypes of group B are not uniformly characterized by essential oil compounds. When stimulated with odor sources of 22 genotypes in a Y-tube olfactometer D. citri preferentially entered the arm containing the volatile oils of Murraya paniculata, confirming orange jasmine as its best host. C. reticulata × C. sinensis was the least preferred genotype, and is characterized by the presence of phytol, (Z)-β-ocimene, and β-elemene, which were not found in the most preferred genotype. We speculate that these three compounds may act as a repellent, making these oils less attractive to D. citri. PMID:27338332

  3. Nested-quantitative PCR approach with improved sensitivity for the detection of low titer levels of Candidatus Liberibacter asiaticus in the Asian citrus psyllid, Diaphorina citri Kuwayama.

    PubMed

    Coy, M R; Hoffmann, M; Kingdom Gibbard, H N; Kuhns, E H; Pelz-Stelinski, K S; Stelinski, L L

    2014-07-01

    Candidatus Liberibacter asiaticus (CLas) is a phloem-limited bacterium transmitted by the Asian citrus psyllid, Diaphorina citri, and the presumptive causal agent of citrus greening disease. The current method of detection for CLas within plant and insect samples is by a presence/absence qPCR assay using the CLas 16S rDNA gene target. Although qPCR is highly sensitive, low bacterial titers or suboptimal qPCR conditions can result in false-negatives. Using a nested qPCR assay, we determined the false-negative rate of the 16S presence/absence qPCR assay was greater than 50%. Studies to determine the performance parameters of the qPCR assays for CLas 16S and Wingless (Wg), the D. citri endogenous gene, using plasmid and psyllid DNA, revealed suboptimal and variable performance of the 16S assay in psyllid samples. Average efficiencies and sensitivity limits of the plasmid assays were 99.0% and 2.7 copies of template for Wg, respectively, and 98.5% and 2.2-22.1 copies for 16S, respectively. Variability in efficiency was significantly greater in psyllid samples for both gene targets compared to the corresponding plasmid assays, and efficiencies as low as 76% were obtained for 16S. A secondary structure analysis revealed the formation of two stem-loop structures that block the forward and probe binding sites in the 16S template, which could hinder amplification. In summary, our results suggest that suboptimal qPCR efficiency is not uncommon for the 16S presence/absence qPCR assay, which combined with lowCLas titers in some samples, could contribute significantly to the under-reporting of CLas infection in psyllid and plant samples. PMID:24769405

  4. Detection of citrus huanglongbing-associated 'Candidatus Liberibacter asiaticus' in citrus and Diaphorina citri in Pakistan, seasonal variability, and implications for disease management.

    PubMed

    Razi, Muhammad F; Keremane, Manjunath L; Ramadugu, Chandrika; Roose, Mikeal; Khan, Iqrar A; Lee, Richard F

    2014-03-01

    We report the detection of the huanglongbing (HLB)-associated bacterium 'Candidatus Liberibacter asiaticus' from both plants and insects in Pakistan and the seasonal variability in the numbers of 'Ca. L. asiaticus'-positive psyllid vector, Diaphorina citri. Our studies showed that 'Ca. L. asiaticus' was detectable from trees in areas with maximum temperatures reaching nearly 50°C (average maximum of 42°C). However, the bacterium was present at very low levels in psyllids both in summer (June to August) and autumn (September to November) in contrast to reports from Florida, where the bacterium was detectable at very high levels during October to November. We hypothesize that hot summer temperatures in Pakistan may interfere with acquisition and replication of 'Ca. L. asiaticus' in psyllids and may lead to dead or non transmissible 'Ca. L. asiaticus' in plants. Psyllid counts were very low in both summer and winter, showed a population peak ('Ca. L. asiaticus'-positive vectors) in spring, and showed a larger peak ('Ca. L. asiaticus'-free psyllids) in autumn. Natural thermotherapy during hot summers and a low vector population during environmental extremes may have played a major role in long-term survival of the citrus industry in Pakistan. These results may be useful in developing management strategies for U.S. citrus industries in Texas and California. PMID:24134720

  5. 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.

    PubMed

    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

  6. 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

    PubMed Central

    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

  7. Herbivory by the insect diaphorina citri induces greater change in citrus plant volatile profile than does infection by the bacterium, Candidatus Liberibacter asiaticus

    PubMed Central

    Hijaz, Faraj; El-Shesheny, Ibrahim; Killiny, Nabil

    2013-01-01

    The volatile organic compound (VOC) profile in plant leaves often changes after biotic and abiotic stresses. Monitoring changes in VOCs in plant leaves could provide valuable information about multitrophic interactions. In the current study, we investigated the effect of Asian citrus psyllid (ACP) infestation, citrus greening pathogen (Candidatus Liberibacter asiaticus [CLas]) infection, and simultaneous attack by ACP and CLas on the VOC content of citrus leaves. Leaf volatiles were extracted using hexane and analyzed with gas chromatography-mass spectrometry (GC-MS). Although ACP is a phloem-sucking insect that causes minimal damage to plant tissues, the relative amount of 21 out of the 27 VOCs increased 2- to 10-fold in ACP-infested plants. The relative amount of d-limonene, β-phelandrene, citronellal, and undecanal were increased 4- to 20- fold in CLas-infected plants. A principle component analysis (PCA) and cluster analysis (CA) showed that VOC patterns of ACP-infested and CLas-infected plants were different from each other and were also different from the controls, while the VOC pattern of double-attacked plants was more like that of the controls than that of ACP-infested or CLas-infected plants. VOC amounts from leaves were compromised when plants were attacked by ACP and CLas. The results of this study showed that a simple direct extraction of citrus leaf volatiles could be successfully used to discriminate between healthy and CLas-infected plants. Information about the effects of insect and pathogen attack on the VOC content profile of plants might contribute to a better understanding of biotic stress. PMID:23857364

  8. Identification of Cytochrome P450 monooxygenases in Diaphornia citri, an economically important psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Twenty P450’s in the CYP monooxygenases were identified in the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). The psyllid is responsible for the transmission of Candidatus Liberibacter asiaticus, the causative agent of huanglongbing ( HLB), also known as citrus greening dise...

  9. Daily and seasonal patterns in abdomen color in Diaphoria citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaphorina citri Kuwayama, a psyllid vector of huanglongbing (citrus greening disease), exhibits three more or less distinct abdomen colors in the adult psyllid: gray/brown, blue/green, and orange/yellow. We explored the daily (in individuals in the laboratory) and seasonal (in a field population) p...

  10. Antibacterial Activity of Alkyl Gallates against Xanthomonas citri subsp. citri

    PubMed Central

    Silva, I. C.; Regasini, L. O.; Petrônio, M. S.; Silva, D. H. S.; Bolzani, V. S.; Belasque, J.; Sacramento, L. V. S.

    2013-01-01

    The plant-pathogenic bacterium Xanthomonas citri subsp. citri is the causal agent of Asiatic citrus canker, a serious disease that affects all the cultivars of citrus in subtropical citrus-producing areas worldwide. There is no curative treatment for citrus canker; thus, the eradication of infected plants constitutes the only effective control of the spread of X. citri subsp. citri. Since the eradication program in the state of São Paulo, Brazil, is under threat, there is a clear risk of X. citri subsp. citri becoming endemic in the main orange-producing area in the world. Here we evaluated the potential use of alkyl gallates to prevent X. citri subsp. citri growth. These esters displayed a potent anti-X. citri subsp. citri activity similar to that of kanamycin (positive control), as evaluated by the resazurin microtiter assay (REMA). The treatment of X. citri subsp. citri cells with these compounds induced altered cell morphology, and investigations of the possible intracellular targets using X. citri subsp. citri strains labeled for the septum and centromere pointed to a common target involved in chromosome segregation and cell division. Finally, the artificial inoculation of citrus with X. citri subsp. citri cells pretreated with alkyl gallates showed that the bacterium loses the ability to colonize its host, which indicates the potential of these esters to protect citrus plants against X. citri subsp. citri infection. PMID:23104804

  11. Development of an ACP facility

    SciTech Connect

    Gil-Sung You; Won-Myung Choung; Jeong-Hoe Ku; il-Je Cho; Dong-Hak Kook; Kie-Chan Kwon; Eun-Pyo Lee; Ji-Sup Yoon; Seong-Won Park; Won-Kyung Lee

    2007-07-01

    KAERI has been developing an advanced spent fuel conditioning process (ACP). The ACP facility for a process demonstration consists of two air-sealed type hot cells. The safety analysis results showed that the facility was designed safely. The relevant integrated performance tests were also carried out successfully. (authors)

  12. Modified acyl-ACP desaturase

    DOEpatents

    Cahoon, Edgar B.; Shanklin, John; Lindgvist, Ylva; Schneider, Gunter

    1998-01-06

    Disclosed is a methods for modifying the chain length and double bond positional specificities of a soluble plant fatty acid desaturase. More specifically, the method involves modifying amino acid contact residues in the substrate binding channel of the soluble fatty acid desaturase which contact the fatty acid. Specifically disclosed is the modification of an acyl-ACP desaturase. Amino acid contact residues which lie within the substrate binding channel are identified, and subsequently replaced with different residues to effect the modification of activity.

  13. Modified Acyl-ACP desaturase

    DOEpatents

    Cahoon, Edgar B.; Shanklin, John; Lindqvist, Ylva; Schneider, Gunter

    1999-03-30

    Disclosed is a method for modifying the chain length and double bond positional specificities of a soluble plant fatty acid desaturase. More specifically, the method involves modifying amino acid contact residues in the substrate binding channel of the soluble fatty acid desaturase which contact the fatty acid. Specifically disclosed is the modification of an acyl-ACP desaturase. Amino acid contact residues which lie within the substrate binding channel are identified, and subsequently replaced with different residues to effect the modification of activity.

  14. Mannose 6 Dephosphorylation of Lysosomal Proteins Mediated by Acid Phosphatases Acp2 and Acp5

    PubMed Central

    Makrypidi, Georgia; Damme, Markus; Müller-Loennies, Sven; Trusch, Maria; Schmidt, Bernhard; Schlüter, Hartmut; Heeren, Joerg; Lübke, Torben; Saftig, Paul

    2012-01-01

    Mannose 6-phosphate (Man6P) residues represent a recognition signal required for efficient receptor-dependent transport of soluble lysosomal proteins to lysosomes. Upon arrival, the proteins are rapidly dephosphorylated. We used mice deficient for the lysosomal acid phosphatase Acp2 or Acp5 or lacking both phosphatases (Acp2/Acp5−/−) to examine their role in dephosphorylation of Man6P-containing proteins. Two-dimensional (2D) Man6P immunoblot analyses of tyloxapol-purified lysosomal fractions revealed an important role of Acp5 acting in concert with Acp2 for complete dephosphorylation of lysosomal proteins. The most abundant lysosomal substrates of Acp2 and Acp5 were identified by Man6P affinity chromatography and mass spectrometry. Depending on the presence of Acp2 or Acp5, the isoelectric point of the lysosomal cholesterol-binding protein Npc2 ranged between 7.0 and 5.4 and may thus regulate its interaction with negatively charged lysosomal membranes at acidic pH. Correspondingly, unesterified cholesterol was found to accumulate in lysosomes of cultured hepatocytes of Acp2/Acp5−/− mice. The data demonstrate that dephosphorylation of Man6P-containing lysosomal proteins requires the concerted action of Acp2 and Acp5 and is needed for hydrolysis and removal of degradation products. PMID:22158965

  15. Modified Acyl-ACP desaturase

    DOEpatents

    Cahoon, E.B.; Shanklin, J.; Lindqvist, Y.; Schneider, G.

    1999-03-30

    Disclosed is a method for modifying the chain length and double bond positional specificities of a soluble plant fatty acid desaturase. More specifically, the method involves modifying amino acid contact residues in the substrate binding channel of the soluble fatty acid desaturase which contact the fatty acid. Specifically disclosed is the modification of an acyl-ACP desaturase. Amino acid contact residues which lie within the substrate binding channel are identified, and subsequently replaced with different residues to effect the modification of activity. 2 figs.

  16. Modified acyl-ACP desaturase

    DOEpatents

    Cahoon, E.B.; Shanklin, J.; Lindgvist, Y.; Schneider, G.

    1998-01-06

    Disclosed is a method for modifying the chain length and double bond positional specificities of a soluble plant fatty acid desaturase. More specifically, the method involves modifying amino acid contact residues in the substrate binding channel of the soluble fatty acid desaturase which contact the fatty acid. Specifically disclosed is the modification of an acyl-ACP desaturase. Amino acid contact residues which lie within the substrate binding channel are identified, and subsequently replaced with different residues to effect the modification of activity. 1 fig.

  17. Synthetic substrate-borne vibrational signals that elicit Asian citrus psyllid communicatory and search responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian Citrus Psyllid (ACP), Diaphorina citri Kuwayama, vectors a harmful bacterium, Candidatus Liberibacter asiaticus, that causes huanglongbing, an economically devastating disease of citrus. Adult male and female ACP transmit vibratory communication signals over 10-50-cm distances within their...

  18. Evaluation of management programs for protecting young citrus plantings from huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asiatic huanglongbing (HLB) is a devastating disease of citrus associated in North America with the bacterium ‘Candidatus Liberibacter asiaticus’ (LAS) vectored by the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama. ACP management is considered a vital component of a program aimed at reducing...

  19. Psyllid biology: expressed genes in adult Asian citrus psyllids, Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    These results advance the field of psyllid research by identifying genes and their proteins which function in: physiology, feeding, disease transmission, and the development of insecticide resistance. This was accomplished by using the molecular approach of a large-scale 5' end sequencing project of...

  20. A comparison of sticky traps for monitoring Asian citrus psyllid (Diaphorina citri Kuwayama)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Six types of sticky card traps differing in color and trapping adhesive were evaluated for monitoring Asian citrus psyllid in citrus in the United States (Florida and Texas). Spectral reflectance measurements were taken to categorize the color (wavelength) spectrum of each trap. Three of the traps (...

  1. Whole genome sequence of “Candidatus Profftella armatura” from Diaphorina citri in Guangdong, China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genome of “Candidatus Profftella armatura” strain YCPA, a symbiont of Asian citrus psyllid, from Guangdong, China, was sequenced. The strain chromosome was 457,565 bp with 24.3% G+C content, 364 predicted open reading frames (ORFs), and 38 RNA genes. The strain also contains a 5,458 bp plasmid, ...

  2. Screening Citrus germplasm for tolerance to HLB and Diaphorina citri--progress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article summarizes a project that is being funded in part by the California Citrus Research Board. In a previous field trial, 87 genotypes of citrus were planted in the field in Florida and the different genotypes were evaluated for tolerance to Asian citrus psyllid, citrus leaf miner, and hua...

  3. Reovirus-like sequences isolated from adult Asian citrus psyllid, (Hemiptera: Psyllidae: Diaphorina citri)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Though wide spread in nature, this is the first report of a Fijivirus from North America and which was detected in a new virus host species, the Asian citrus psyllid. Few viruses have ever been reported from psyllids. We discovered an insect infecting virus in field collected Asian citrus psyllids i...

  4. Reovirus-like sequences isolated from adult Asian citrus psyllid, (Hemiptera: Psyllidae: Diaphorina citri)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Though wide spread in nature, this is the first report of a fijiviruses from North America detected in a new virus host species, the Asian citrus psyllid. Few viruses have ever been reported from psyllids. We discovered an insect infecting virus in field collected Asian citrus psyllids in Florida. T...

  5. Antibiosis and antixenosis resistance of Poncirus and Citrus x Poncirus germplasm to Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, which is a worldwide pest that spreads citrus greening disease, may best be controlled by finding varieties of citrus that are resistant to the psyllid. We tested trifoliate citrus and trifoliate hybrids for resistance to the psyllid. Trifoliates were nearly all resistant,...

  6. Metagenomic analysis of Candidatus Liberibacter asiaticus in naturally populated psyllids (Diaphorina citri) using BAC libraries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Candidatus Liberibacter asiaticus (Las) is the most prevalent species of three species of Ca. Liberibacter causing citrus huanglongbing (HLB) in the world. The Las genome sequence published in 2009 was obtained from a single Las-infected psyllid using metagenomic approach. Studies of genetic divers...

  7. Xanthomonas citri subsp. citri type IV Pilus is required for twitching motility, biofilm development, and adherence.

    PubMed

    Dunger, German; Guzzo, Cristiane R; Andrade, Maxuel O; Jones, Jeffrey B; Farah, Chuck S

    2014-10-01

    Bacterial type IV pili (T4P) are long, flexible surface filaments that consist of helical polymers of mostly pilin subunits. Cycles of polymerization, attachment, and depolymerization mediate several pilus-dependent bacterial behaviors, including twitching motility, surface adhesion, pathogenicity, natural transformation, escape from immune system defense mechanisms, and biofilm formation. The Xanthomonas citri subsp. citri strain 306 genome codes for a large set of genes involved in T4P biogenesis and regulation and includes several pilin homologs. We show that X. citri subsp. citri can exhibit twitching motility in a manner similar to that observed in other bacteria such as Pseudomonas aeruginosa and Xylella fastidiosa and that this motility is abolished in Xanthomonas citri subsp. citri knockout strains in the genes coding for the major pilin subunit PilAXAC3241, the ATPases PilBXAC3239 and PilTXAC2924, and the T4P biogenesis regulators PilZXAC1133 and FimXXAC2398. Microscopy analyses were performed to compare patterns of bacterial migration in the wild-type and knockout strains and we observed that the formation of mushroom-like structures in X. citri subsp. citri biofilm requires a functional T4P. Finally, infection of X. citri subsp. citri cells by the bacteriophage (ΦXacm4-11 is T4P dependent. The results of this study improve our understanding of how T4P influence Xanthomonas motility, biofilm formation, and susceptibility to phage infection. PMID:25180689

  8. 7 CFR 701.44 - Agricultural Conservation Program (ACP) contracts.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... be subject to, the regulations for ACP contracts and the ACP program that were contained in the 7 CFR... 7 Agriculture 7 2012-01-01 2012-01-01 false Agricultural Conservation Program (ACP) contracts. 701... AGENCY, DEPARTMENT OF AGRICULTURE AGRICULTURAL CONSERVATION PROGRAM EMERGENCY CONSERVATION...

  9. 7 CFR 701.44 - Agricultural Conservation Program (ACP) contracts.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... be subject to, the regulations for ACP contracts and the ACP program that were contained in the 7 CFR... 7 Agriculture 7 2014-01-01 2014-01-01 false Agricultural Conservation Program (ACP) contracts. 701... AGENCY, DEPARTMENT OF AGRICULTURE AGRICULTURAL CONSERVATION PROGRAM EMERGENCY CONSERVATION...

  10. 7 CFR 701.44 - Agricultural Conservation Program (ACP) contracts.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... be subject to, the regulations for ACP contracts and the ACP program that were contained in the 7 CFR... 7 Agriculture 7 2011-01-01 2011-01-01 false Agricultural Conservation Program (ACP) contracts. 701... AGENCY, DEPARTMENT OF AGRICULTURE AGRICULTURAL CONSERVATION PROGRAM EMERGENCY CONSERVATION...

  11. 7 CFR 701.44 - Agricultural Conservation Program (ACP) contracts.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... be subject to, the regulations for ACP contracts and the ACP program that were contained in the 7 CFR... 7 Agriculture 7 2013-01-01 2013-01-01 false Agricultural Conservation Program (ACP) contracts. 701... AGENCY, DEPARTMENT OF AGRICULTURE AGRICULTURAL CONSERVATION PROGRAM EMERGENCY CONSERVATION...

  12. 7 CFR 701.44 - Agricultural Conservation Program (ACP) contracts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... regulations for ACP contracts and the ACP program that were contained in the 7 CFR, parts 700 to 899, edition... 7 Agriculture 7 2010-01-01 2010-01-01 false Agricultural Conservation Program (ACP) contracts. 701... AGENCY, DEPARTMENT OF AGRICULTURE AGRICULTURAL CONSERVATION PROGRAM EMERGENCY CONSERVATION PROGRAM...

  13. Foliar application of biofilm formation-inhibiting compounds enhances control of citrus canker caused by Xanthomonas citri subsp. citri.

    PubMed

    Li, Jinyun; Wang, Nian

    2014-02-01

    Citrus canker caused by the bacterium Xanthomonas citri subsp. citri is an economically important disease of citrus worldwide. Biofilm formation plays an important role in early infection of X. citri subsp. citri on host leaves. In this study, we assessed the hypothesis that small molecules inhibiting biofilm formation reduce X. citri subsp. citri infection and enhance the control of citrus canker disease. D-leucine and 3-indolylacetonitrile (IAN) were found to prevent biofilm formation by X. citri subsp. citri on different abiotic surfaces and host leaves at a concentration lower than the minimum inhibitory concentration (MIC). Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis indicated that IAN repressed expression of chemotaxis/motility-related genes in X. citri subsp. citri. In laboratory experiments, planktonic and biofilm cells of X. citri subsp. citri treated with D-leucine and IAN, either alone or in combination, were more susceptible to copper (CuSO4) than those untreated. In greenhouse assays, D-leucine and IAN applied alone or combined with copper reduced both the number of canker lesions and bacterial populations of X. citri subsp. citri on citrus host leaves. This study provides the basis for the use of foliar-applied biofilm inhibitors for the control of citrus canker alone or combined with copper-based bactericides. PMID:23901828

  14. A comparison of the bioassay test and culture to detect Xanthomonas citri subsp. citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (caused by Xanthomonas citri subsp. citri [Xcc]) can cause yield loss of susceptible citrus and result in trade restrictions of fresh fruit. For both regulatory purposes and epidemiological studies, accurate detection and quantification of viable inoculum is critical. Two accepted meth...

  15. Predisposition of citrus foliage to infection with Xanthomonas citri subsp. citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (caused by Xanthomonas citri subsp. citri, Xcc) is a serious disease of susceptible citrus in Florida and other citrus-growing areas of the world. The effect of leaf preconditioning as a route for entry of the bacteria is poorly characterized. A series of experiments were designed to i...

  16. Predisposition of citrus foliage to infection with Xanthomonas citri subsp. citri.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (caused by Xanthomonas citri subsp. citri, Xcc) is a serious disease of susceptible citrus in Florida and other citrus-growing areas of the world. The specific effects of predisposing factors for bacterial penetration of leaves are poorly characterized. Experiments were designed to inv...

  17. Resistance of sweet orange Pera (Citrus sinensis) genotypes to Xanthomonas citri subsp. citri under field conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker control is based on protection measures and eradication of plants infected with Xanthomonas citri subsp. citri. Although these measures show satisfactory results, the use of resistant genotypes is an important alternative for citrus canker control. The aim of this study was to evaluate...

  18. Orchard and nursery dynamics of the effect of interplanting citrus with guava for Huanglongbing, vector, and disease management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), is an important pest of citrus in the United States of America primarily because it vectors ‘Candidatus Liberibacter asiaticus’, the bacterium putatively responsible for Asiatic huanglongbing (HLB). Asiatic HLB is con...

  19. Transmission and Propagation of ‘Candidatus Liberibacter asiaticus’ by Grafting with Individual Citrus Leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a chronic, progressive decline disease in citrus associated with systemic infection by the bacterium Candidatus Liberibacter asiaticus (CLas). Transmission in the field is by the Asian citrus psyllid (ACP), Diaphorina citri, Kuwayama. Experimental propagation of CLas is done c...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  1. Factors affecting transmission rates of 'Candidatus Liberibacter asiaticus' by Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri, is an important pest because it transmits a bacterium ‘Candidatus Liberibacter asiaticus’ (CLas) responsible for a serious disease of citrus known as Asiatic huanglongbing (citrus greening disease). USDA-ARS researchers recently established a program...

  2. Evaluating citrus germplasm for huanglongbing (HLB) resistance: USDA-ARS Inoculation Program

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri, is an important pest because it vectors bacteria responsible for a serious disease of citrus known as huanglongbing (citrus greening disease). USDA-ARS researchers recently established a program for screening citrus germplasm for resistance to the di...

  3. Resistance of poncirus and citrus x poncirus germplasm to the Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, has spread to citrus growing regions nearly worldwide and transmits phloem-limited bacteria (Candidatus Liberibacter spp.) that are putatively responsible for citrus greening disease. Host plant resistance may provide the most effective cont...

  4. Increased infestation of Asian citrus psyllids on cold treated sour orange seedlings: Its possible relation to biochemical changes in leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cold-stressed sour orange seedling (Citrus aurantium L.) attracted significantly more Asian citrus psyllid (ACP) (Diaphorina citri Kuwayama) during 5h and 24h recovery periods compared to control plants in choice test experiment. Cold stressed plants were held/ placed at 6 ± 1°C for 6 days and then ...

  5. Interference by western flower thrips in rearing Asian citrus psyllid: damage to host plants and facultative predation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is an important pest of citrus primarily because it vectors a bacterium responsible for a serious citrus disease known as huanglongbing (HLB) (also known as citrus greening disease). Researchers seeking solutions to HLB often depend on labor...

  6. Efficacy of area-wide inoculum reduction and vector control on temporal progress of huanglongbing in Young Sweet orange plantings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), caused by Candidatus Liberibacter spp. and transmitted by the Asian citrus psyllid Diaphorina citri (ACP), is an important threat to citrus industries worldwide, causing significant yield loss. The current recommended strategies to manage HLB are to: (i) eliminate HLB symptomat...

  7. Changes in free amino acids and polyamine levels in Satsuma leaves in response to Asian citrus psyllid infestation and water stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of biotic and abiotic stresses on changes in amino acids and polyamine levels in Satsuma orange (Citrus unshiu; cultivar Owari) leaves were investigated. Asian citrus psyllids (Diaphorina citri (Kuwayama) (ACP) infestation was used to induce biotic stress while a water deficit was impos...

  8. Diurnal patterns in flight activity and effects of light on host finding behavior of the Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae), is an invasive pest of citrus in the United States. The psyllid feeds and reproduces primarily on new flush growth of citrus and other rutaceous plants. Because it vectors the bacterial causal agents of the deadly citrus green...

  9. Sensitive detection of Spiroplasma citri by targeting prophage sequences

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spiroplasma citri is a phloem limited and nutritionally fastidious wall-less bacterium causing citrus stubborn disease (CSD) in California. An important step in CSD management is early detection of S. citri. Because isolation of S. citri is technically demanding and time consuming, current detection...

  10. Fortunella margarita Transcriptional Reprogramming Triggered by Xanthomonas citri subsp. citri

    PubMed Central

    2011-01-01

    Background Citrus canker disease caused by the bacterial pathogen Xanthomonas citri subsp. citri (Xcc) has become endemic in areas where high temperature, rain, humidity, and windy conditions provide a favourable environment for the dissemination of the bacterium. Xcc is pathogenic on many commercial citrus varieties but appears to elicit an incompatible reaction on the citrus relative Fortunella margarita Swing (kumquat), in the form of a very distinct delayed necrotic response. We have developed subtractive libraries enriched in sequences expressed in kumquat leaves during both early and late stages of the disease. The isolated differentially expressed transcripts were subsequently sequenced. Our results demonstrate how the use of microarray expression profiling can help assign roles to previously uncharacterized genes and elucidate plant pathogenesis-response related mechanisms. This can be considered to be a case study in a citrus relative where high throughput technologies were utilized to understand defence mechanisms in Fortunella and citrus at the molecular level. Results cDNAs from sequenced kumquat libraries (ESTs) made from subtracted RNA populations, healthy vs. infected, were used to make this microarray. Of 2054 selected genes on a customized array, 317 were differentially expressed (P < 0.05) in Xcc challenged kumquat plants compared to mock-inoculated ones. This study identified components of the incompatible interaction such as reactive oxygen species (ROS) and programmed cell death (PCD). Common defence mechanisms and a number of resistance genes were also identified. In addition, there were a considerable number of differentially regulated genes that had no homologues in the databases. This could be an indication of either a specialized set of genes employed by kumquat in response to canker disease or new defence mechanisms in citrus. Conclusion Functional categorization of kumquat Xcc-responsive genes revealed an enhanced defence

  11. Identification of an Extracellular Endoglucanase That Is Required for Full Virulence in Xanthomonas citri subsp. citri

    PubMed Central

    Sun, Dongling; Zhuo, Tao; Fan, Xiaojing; Zou, Huasong

    2016-01-01

    Xanthomonas citri subsp. citri causes citrus canker disease, which is characterized by the formation of water-soaked lesions, white or yellow spongy pustules and brown corky canker. In this work, we report the contribution of extracellular endoglucanase to canker development during infection. The ectopic expression of nine putative cellulases in Escherichia coli indicated that two endoglucanases, BglC3 and EngXCA, show carboxymethyl cellulase activity. Both bglC3 and engXCA genes were transcribed in X. citri subsp. citri, however, only BglC3 protein was detected outside the cell in western blot analysis. The deletion of bglC3 gene resulted in complete loss of extracellular carboxymethyl cellulase activity and delayed the onset of canker symptoms in both infiltration- and wound-inoculation assays. When growing in plant tissue, the cell density of bglC3 mutant was lower than that of the wild type. Our data demonstrated that BglC3 is an extracellular endoglucanase required for the full virulence of X. citri subsp. citri. PMID:26950296

  12. Use of carnauba based carrier for copper sprays reduces infection by Xanthomonas citri subsp. citri and Diaporthe citri in Florida commercial grapefruit groves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asiatic citrus canker caused by Xanthomonas citri subsp. citri (Xcc), a bacterial disease of citrus, was first documented on Florida citrus in the early 1900’s. At that time the disease was managed, only to return in the 1980’s and 90’s and to finally remain uncontrolled in 2004. Xcc is most active ...

  13. Shewanella oneidensis FabB: A β-ketoacyl-ACP Synthase That Works with C16:1-ACP

    PubMed Central

    Luo, Qixia; Li, Meng; Fu, Huihui; Meng, Qiu; Gao, Haichun

    2016-01-01

    It is established that Escherichia coli β-ketoacyl-ACP synthase (KAS) I (encoded by EcfabB) is the primary, if not exclusive, factor for elongation of the cis-3-decenoyl-ACP (C10:1-ACP) but not effective with C16:1- or longer-chain-ACPs. To test the extent to which these features apply to KAS I proteins in other species, in this study, we examined the physiological role of FabB in Shewanella oneidensis, an excellent model for researching type II fatty acid synthetic (FAS) system and its regulation. We showed that the loss of either FabA (the enzyme that introduces double bond) or FabB, in the absence of DesA which desaturizes C16 and C18 to generate respective C16:1 and C18:1, leads to a UFA auxotroph. However, fatty acid profiles of membrane phospholipid of the fabA and fabB mutants are significantly different, suggesting that FabB participates in steps beyond elongation of C10:1-ACP. Further analyses demonstrated that S. oneidensis FabB differs from EcFabB in that (i) it is not the only enzyme capable of catalyzing elongation of the cis-3-decenoyl-ACP produced by FabA, (ii) it plays a critical role in elongation of C16:1- and longer-chain-ACPs, and (iii) its overproduction is detrimental. PMID:27014246

  14. The ACP (Advanced Computer Program) Branch bus and real-time applications of the ACP multiprocessor system

    SciTech Connect

    Hance, R.; Areti, H.; Atac, R.; Biel, J.; Cook, A.; Fischler, M.; Gaines, I.; Husby, D.; Nash, T.; Zmuda, T.

    1987-05-08

    The ACP Branchbus, a high speed differential bus for data movement in multiprocessing and data acquisition environments, is described. This bus was designed as the central bus in the ACP multiprocessing system. In its full implementation with 16 branches and a bus switch, it will handle data rates of 160 MByte/sec and allow reliable data transmission over inter rack distances. We also summarize applications of the ACP system in experimental data acquisition, triggering and monitoring, with special attention paid to FASTBUS environments.

  15. Studies of in aere formed stylet sheath from the Asian citrus psyllid (Diaphorina citri, Hemiptera: Psyllidae) and other phytophagous Hemiptera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stylet sheath formation is a common feature among phytophagous hemipterans. These sheaths are considered essential to promote a successful feeding event of these piercing-sucking insects. The stylet sheath composition is unknown and it is suggested that it forms through interactions with external (h...

  16. Asian citrus psyllids and shade: Survival of Diaphorina citri on Murraya exotica foliage exposed to different levels of light

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using shade cloths of different densities, potted individuals of Murraya exotica (Rutaceae) were exposed to levels of photosynthetic radiation (PAR) varying from 48 µmol photons per meter2 per second to 1562 µmol photons per meter2 per second (average of three readings taken at noon during condition...

  17. Detection of Candidatus Liberibacter asiaticus associated with huanglongbing disease in the salivary glands and alimentary canal of Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Candidatus Liberibacter asiaticus (Las) has been strongly implicated as the causative agent of huanglongbing (HLB), or citrus greening, which is the most devastating citrus disease in Florida and other parts of the world. HLB is transmitted in a persistent manner by psyllid vectors and in the US and...

  18. The Interactions of CPP–ACP with Saliva

    PubMed Central

    Huq, Noorjahan Laila; Myroforidis, Helen; Cross, Keith J.; Stanton, David P.; Veith, Paul D.; Ward, Brent R.; Reynolds, Eric C.

    2016-01-01

    The repair of early dental caries lesions has been demonstrated by the application of the remineralisation technology based on casein phosphopeptide-stabilised amorphous calcium phosphate complexes (CPP–ACP). These complexes consist of an amorphous calcium phosphate mineral phase stabilised and encapsulated by the self-assembly of milk-derived phosphopeptides. During topical application of CPP–ACP complexes in the oral cavity, the CPP encounters the enamel pellicle consisting of salivary proteins and peptides. However the interactions of the CPP with the enamel salivary pellicle are not known. The studies presented here reveal that the predominant peptides of CPP–ACP complexes do interact with specific salivary proteins and peptides of the enamel pellicle, and provide a mechanism by which the CPP–ACP complexes are localised at the tooth surface to promote remineralisation. PMID:27294918

  19. The Interactions of CPP-ACP with Saliva.

    PubMed

    Huq, Noorjahan Laila; Myroforidis, Helen; Cross, Keith J; Stanton, David P; Veith, Paul D; Ward, Brent R; Reynolds, Eric C

    2016-01-01

    The repair of early dental caries lesions has been demonstrated by the application of the remineralisation technology based on casein phosphopeptide-stabilised amorphous calcium phosphate complexes (CPP-ACP). These complexes consist of an amorphous calcium phosphate mineral phase stabilised and encapsulated by the self-assembly of milk-derived phosphopeptides. During topical application of CPP-ACP complexes in the oral cavity, the CPP encounters the enamel pellicle consisting of salivary proteins and peptides. However the interactions of the CPP with the enamel salivary pellicle are not known. The studies presented here reveal that the predominant peptides of CPP-ACP complexes do interact with specific salivary proteins and peptides of the enamel pellicle, and provide a mechanism by which the CPP-ACP complexes are localised at the tooth surface to promote remineralisation. PMID:27294918

  20. Selection on the Drosophila seminal fluid protein Acp62F

    PubMed Central

    Wong, Alex; Rundle, Howard

    2013-01-01

    Sperm competition and sexual conflict are thought to underlie the rapid evolution of reproductive proteins in many taxa. While comparative data are generally consistent with these hypotheses, few manipulative tests have been conducted and those that have provided contradictory results in some cases. Here, we use both comparative and experimental techniques to investigate the evolution of the Drosophila melanogaster seminal fluid protein Acp62F, a protease inhibitor for which extensive functional tests have yielded ambiguous results. Using between-species sequence comparisons, we show that Acp62F has been subject to recurrent positive selection. In addition, we experimentally evolved populations polymorphic for an Acp62F null allele over eight generations, manipulating the opportunities for natural and sexual selection. We found that the Acp62F null allele increased in frequency in the presence of natural selection, with no effect of sexual selection. PMID:23919141

  1. 26 CFR 1.401(m)-2 - ACP test.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... satisfy the ACP test, but not in excess of 100%. In this case, an increase in the match rate from 50% to... under the ACP test only to the extent they do not exceed 25.00% of compensation. In this case, all of... determined under § 1.401(m)-2(b)(2)(iv) (as it appeared in the April 1, 2007, edition of 26 CFR part 1)....

  2. Quantitative Detection of Spiroplasma Citri by Real Time PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is a need to develop an accurate and rapid method to detect Spiroplasma citri, the causal agent of citrus stubborn disease for use in epidemiology studies. Quantitative real-time PCR was developed for detection of S. citri. Two sets of primers based on sequences from the P58 putative adhesin ...

  3. Transmission of Spiroplasma citri to Carrots by Circulifer tenellus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spiroplasma citri is a wall-less bacterium that causes citrus stubborn disease (CSD) and brittle root in horseradish. Recently, carrot purple disease was reported in Washington State, and attributed to S. citri, but the mechanisms of transmission and fulfillment of Koch’s postulates were not complet...

  4. Substrate Recognition by β-Ketoacyl-ACP Synthases†

    PubMed Central

    Borgaro, Janine G.; Chang, Andrew; Machutta, Carl A.; Zhang, Xujie; Tonge, Peter J.

    2011-01-01

    β-Ketoacyl-ACP synthase (KAS) enzymes catalyze Claisen condensation reactions in the fatty acid biosynthesis pathway. These reactions follow a ping-pong mechanism in which a donor substrate acylates the active site cysteine residue after which the acyl group is condensed with the malonyl-ACP acceptor substrate to form a β-ketoacyl-ACP. In the priming KASIII enzymes the donor substrate is an acyl-CoA while in the elongating KASI and KASII enzymes the donor is an acyl-ACP. Although the KASIII enzyme in Escherichia coli (ecFabH) is essential, the corresponding enzyme in Mycobacterium tuberculosis (mtFabH) is not, suggesting that the KASI or II enzyme in M. tuberculosis (KasA or KasB, respectively) must be able to accept a CoA donor substrate. Since KasA is essential, the substrate specificity of this KASI enzyme has been explored using substrates based on phosphopantetheine, CoA, ACP and AcpM peptide mimics. This analysis has been extended to the KASI and KASII enzymes from E. coli (ecFabB and ecFabF) where we show that a 14 residue malonyl-phosphopantetheine peptide can efficiently replace malonyl-ecACP as the acceptor substrate in the ecFabF reaction. While ecFabF is able to catalyze the condensation reaction when CoA is the carrier for both substrates, the KASI enzymes ecFabB and KasA have an absolute requirement for an ACP substrate as the acyl donor. Provided that this requirement is met, variation in the acceptor carrier substrate has little impact on the kcat/Km for the KASI reaction. For the KASI enzymes we propose that the binding of ecACP (AcpM) results in a conformational change that leads to an open form of the enzyme to which the malonyl acceptor substrate binds. Finally, the substrate inhibition observed when palmitoyl-CoA is the donor substrate for the KasA reaction has implications for the importance of mtFabH in the mycobacterial FASII pathway. PMID:22017312

  5. Substrate recognition by β-ketoacyl-ACP synthases.

    PubMed

    Borgaro, Janine G; Chang, Andrew; Machutta, Carl A; Zhang, Xujie; Tonge, Peter J

    2011-12-13

    β-Ketoacyl-ACP synthase (KAS) enzymes catalyze Claisen condensation reactions in the fatty acid biosynthesis pathway. These reactions follow a ping-pong mechanism in which a donor substrate acylates the active site cysteine residue after which the acyl group is condensed with the malonyl-ACP acceptor substrate to form a β-ketoacyl-ACP. In the priming KASIII enzymes the donor substrate is an acyl-CoA while in the elongating KASI and KASII enzymes the donor is an acyl-ACP. Although the KASIII enzyme in Escherichia coli (ecFabH) is essential, the corresponding enzyme in Mycobacterium tuberculosis (mtFabH) is not, suggesting that the KASI or II enzyme in M. tuberculosis (KasA or KasB, respectively) must be able to accept a CoA donor substrate. Since KasA is essential, the substrate specificity of this KASI enzyme has been explored using substrates based on phosphopantetheine, CoA, ACP, and AcpM peptide mimics. This analysis has been extended to the KASI and KASII enzymes from E. coli (ecFabB and ecFabF) where we show that a 14-residue malonyl-phosphopantetheine peptide can efficiently replace malonyl-ecACP as the acceptor substrate in the ecFabF reaction. While ecFabF is able to catalyze the condensation reaction when CoA is the carrier for both substrates, the KASI enzymes ecFabB and KasA have an absolute requirement for an ACP substrate as the acyl donor. Provided that this requirement is met, variation in the acceptor carrier substrate has little impact on the k(cat)/K(m) for the KASI reaction. For the KASI enzymes we propose that the binding of ecACP (AcpM) results in a conformational change that leads to an open form of the enzyme to which the malonyl acceptor substrate binds. Finally, the substrate inhibition observed when palmitoyl-CoA is the donor substrate for the KasA reaction has implications for the importance of mtFabH in the mycobacterial FASII pathway. PMID:22017312

  6. Expression of Xylella fastidiosa RpfF in citrus disrupts signaling in Xanthomonas citri subsp. citri and thereby its virulence.

    PubMed

    Caserta, R; Picchi, S C; Takita, M A; Tomaz, J P; Pereira, W E L; Machado, M A; Ionescu, M; Lindow, S; De Souza, A A

    2014-11-01

    Xylella fastidiosa and Xanthomonas citri subsp. citri, that cause citrus variegated chlorosis (CVC) and citrus canker diseases, respectively, utilize diffusible signal factor (DSF) for quorum sensing. DSF, produced by RpfF, are similar fatty acids in both organisms, although a different set of genes is regulated by DSF in each species. Because of this similarity, Xylella fastidiosa DSF might be recognized and affect the biology of Xanthomonas citri. Therefore, transgenic Citrus sinensis and Carrizo citrange plants overexpressing the Xylella fastidiosa rpfF were inoculated with Xanthomonas citri and changes in symptoms of citrus canker were observed. X. citri biofilms formed only at wound sites on transgenic leaves and were thicker; however, bacteria were unable to break through the tissue and form pustules elsewhere. Although abundant growth of X. citri occurred at wound sites on inoculated transgenic leaves, little growth was observed on unwounded tissue. Genes in the DFS-responsive core in X. citri were downregulated in bacteria isolated from transgenic leaves. DSF-dependent expression of engA was suppressed in cells exposed to xylem sap from transgenic plants. Thus, altered symptom development appears to be due to reduced expression of virulence genes because of the presence of antagonists of DSF signaling in X. citri in rpfF-expressing plants. PMID:25099341

  7. Bismerthiazol inhibits Xanthomonas citri subsp. citri growth and induces differential expression of citrus defense-related genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker, caused by Xanthomonas citri ssp. citri (Xcc), is a serious disease and causes substantial economic losses to the citrus industry worldwide. The bactericide, bismerthiazol, has been widely used to control rice bacterial blight (Xanthomonas oryzae pv. oryzae). In this paper, we demonstr...

  8. Dispersal of Xanthomonas citri subsp. citri bacteria downwind from harvested, infected fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas axonopodis pv. citri , Xac) is a bacterial disease that severely damages citrus crops. Its recent introduction to Florida has created difficulties with international and domestic trade and movement of citrus material. This study examined the potential dispersal of bacteri...

  9. Mode of action of anticancer peptides (ACPs) from amphibian origin.

    PubMed

    Oelkrug, Christopher; Hartke, Martin; Schubert, Andreas

    2015-02-01

    Although cancer belongs to one of the leading causes of death around the world, fortunately studies have shown that tumor cells have various targets that are susceptible to attack. Interestingly, tumor cells are comprised of cellular membranes, which are altered in chemical composition relative to non-neoplastic cells, giving them an increased net negative charge. These altered membranes are ideal targets for antimicrobial peptides (AMPs) shown to have additional tumoricidal properties and, hence, named anticancer peptides (ACPs). Several hundred ACPs have been explored in vitro and in vivo on various types of cancer. Novel anticancer agents are supposed not to cause serious side effects and the formation of multidrug-resistant tumor cells. During the quest for potent ACPs, promising candidates were isolated from skin secretions of amphibians, such as the granular glands of the Chinese brown frog, Rana chensinensis. ACPs have to be selective to cancer cells and should not induce strong immune responses or be cleared from the body rapidly. Several modifications can improve ACPs either by optimizing the primary structure rationally or randomly or even by introducing other chemical modifications. PMID:25667440

  10. New replacement name for Chrysotus infirmus Wei, Zhang & Zhou, 2014 (Diptera, Dolichopodidae, Diaphorinae)

    PubMed Central

    Zhou, Zheng-Xiang

    2016-01-01

    Abstract Chrysotus weii Zhou, nom. n., the new replacement name is proposed for the species Chrysotus infirmus Wei, Zhang & Zhou, 2014 (Diptera: Brachycera: Dolichopodidae: Diaphorinae), which was preoccupied by Chrysotus infirmus Parent, 1933. PMID:27551236

  11. ACP research and scientific coordination: Annual performance report

    SciTech Connect

    Hales, J.M.

    1992-09-17

    This research grant addresses two primary objectives: 1. Conduct of specific research tasks under the DOE Atmospheric Chemistry Program (ACP), and 2. Provision of scientific coordination for the Atmospheric Chemistry Program. In summary, the project is progressing essentially as expected, with some minor exceptions. Higher than anticipated demands within Objective 2, associated primarily with the ACP Ozone Project and the recompetition of the National Laboratories protion of ACP, have resulted in a somewhat higher proportionate emphasis on the coordination activities associated with this objective. Also, the immediate need for pre-campaign modeling of the North Pacific has resulted in an acceleration of the Pacific modeling task relative to other tasks, particularly the Atlantic modeling task. Modeling activities in general have been delayed somewhat because of the noted Objective 2 demands and because of the extended time that was necessary to complete financial agreements for this grant.

  12. Palmitoyl-acyl carrier protein (ACP) thioesterase and the evolutionary origin of plant acyl-ACP thioesterases.

    PubMed Central

    Jones, A; Davies, H M; Voelker, T A

    1995-01-01

    Acyl-acyl carrier protein (ACP) thioesterases play an essential role in chain termination during de novo fatty acid synthesis and in the channeling of carbon flux between the two lipid biosynthesis pathways in plants. We have discovered that there are two distinct but related thioesterase gene classes in higher plants, termed FatA and FatB, whose evolutionary divergence appears to be ancient. FatA encodes the already described 18:1-ACP thioesterase. In contrast, FatB representatives encode thioesterases preferring acyl-ACPs having saturated acyl groups. We unexpectedly obtained a 16:0-ACP thioesterase cDNA from Cuphea hookeriana seed, which accumulate predominantly 8:0 and 10:0. The 16:0 thioesterase transcripts were found in non-seed tissues, and expression in transgenic Brassica napus led to the production of a 16:0-rich oil. We present evidence that this type of FatB gene is ancient and ubiquitous in plants and that specialized plant medium-chain thioesterases have evolved independently from such enzymes several times during angiosperm evolution. Also, the ubiquitous 18:1-ACP thioesterase appears to be a derivative of a 16:0 thioesterase. PMID:7734968

  13. Evolution of acyl-ACP-thioesterases and β-ketoacyl-ACP-synthases revealed by protein-protein interactions

    PubMed Central

    Beld, Joris; Blatti, Jillian L.; Behnke, Craig; Mendez, Michael; Burkart, Michael D.

    2014-01-01

    The fatty acid synthase (FAS) is a conserved primary metabolic enzyme complex capable of tolerating cross-species engineering of domains for the development of modified and overproduced fatty acids. In eukaryotes, acyl-acyl carrier protein thioesterases (TEs) off-load mature cargo from the acyl carrier protein (ACP), and plants have developed TEs for short/medium-chain fatty acids. We showed that engineering plant TEs into the green microalga Chlamydomonas reinhardtii does not result in the predicted shift in fatty acid profile. Since fatty acid biosynthesis relies on substrate recognition and protein-protein interactions between the ACP and its partner enzymes, we hypothesized that plant TEs and algal ACP do not functionally interact. Phylogenetic analysis revealed major evolutionary differences between FAS enzymes, including TEs and ketoacyl synthases (KSs), in which the former is present only in some species, whereas the latter is present in all, and has a common ancestor. In line with these results, TEs appeared to be selective towards their ACP partners whereas KSs showed promiscuous behavior across bacterial, plant and algal species. Based on phylogenetic analyses, in silico docking, in vitro mechanistic crosslinking and in vivo algal engineering, we propose that phylogeny can predict effective interactions between ACPs and partner enzymes. PMID:25110394

  14. Acalabrutinib (ACP-196): a selective second-generation BTK inhibitor.

    PubMed

    Wu, Jingjing; Zhang, Mingzhi; Liu, Delong

    2016-01-01

    More and more targeted agents become available for B cell malignancies with increasing precision and potency. The first-in-class Bruton's tyrosine kinase (BTK) inhibitor, ibrutinib, has been in clinical use for the treatment of chronic lymphocytic leukemia, mantle cell lymphoma, and Waldenstrom's macroglobulinemia. More selective BTK inhibitors (ACP-196, ONO/GS-4059, BGB-3111, CC-292) are being explored. Acalabrutinib (ACP-196) is a novel irreversible second-generation BTK inhibitor that was shown to be more potent and selective than ibrutinib. This review summarized the preclinical research and clinical data of acalabrutinib. PMID:26957112

  15. Identification and characterization of biofilm formation-defective mutants of Xanthomonas citri subsp. citri.

    PubMed

    Malamud, Florencia; Homem, Rafael Augusto; Conforte, Valeria Paola; Yaryura, Pablo Marcelo; Castagnaro, Atilio Pedro; Marano, María Rosa; do Amaral, Alexandre Morais; Vojnov, Adrián Alberto

    2013-09-01

    Xanthomonas citri subsp. citri (Xcc) develops a biofilm structure both in vitro and in vivo. Despite all the progress achieved by studies regarding biofilm formation, many of its mechanisms remain poorly understood. This work focuses on the identification of new genes involved in biofilm formation and how they are related to motility, virulence and chemotaxis in Xcc. A Tn5 library of approximately 6000 Xcc (strain 306) mutants was generated and screened to search for biofilm formation defective strains. We identified 23 genes not previously associated with biofilm formation. The analysis of the 23 mutants not only revealed the involvement of new genes in biofilm formation, but also reinforced the importance of exopolysaccharide production, motility and cell surface structures in this process. This collection of biofilm-defective mutants underscores the multifactorial genetic programme underlying the establishment of biofilm in Xcc. PMID:23813675

  16. A Community-oriented CEOS Atmospheric Composition Portal (ACP)

    NASA Astrophysics Data System (ADS)

    Bernonville, S.; Goussev, O.; Falke, S.; Lindsay, F.; Lynnes, C. S.; Yang, W.; Zhao, P.; Johnson, J.

    2012-04-01

    The Atmospheric Composition Constellation (ACC) and the Workgroup for Information Systems and Services (WGISS) within the Committee on Earth Observation Satellites (CEOS) is developing a portal to support interoperability among the atmospheric composition research and applications communities. The CEOS Atmospheric Composition Portal (ACP) is defining approaches for providing data access, tools and contextual guidance for an international suite of remote sensing datasets. An initial prototype provides access to data services and analysis tools hosted by the World Data Center for Remote Sensing of the Atmosphere (WDC-RSAT), NASA's Goddard Earth Sciences Data and Information Services Center (GES DISC) and DataFed. Distributed access to data is implemented via interoperability standards, including the Open Geospatial Consortium's (OGC) Web Map Service (WMS) and Web Coverage Service (WCS). A fundamental aspect to the design, implementation and evolution of the ACP is community collaboration. The portal is intended as a community resource that is created through collaboration across remotely sensed atmospheric composition data organizations and used by a variety of groups across the climate, air quality, and stratospheric ozone domains. The implementation of interoperability standards in the ACP has involved coordination on identifying the most applicable standards and the definition of community-specific conventions to ensure consistent adoption of standards. This presentation includes an overview of the ACP, its community oriented approach, and use of community-conventions in achieving standards-based interoperability.

  17. Specificities of the Acyl-Acyl Carrier Protein (ACP) Thioesterase and Glycerol-3-Phosphate Acyltransferase for Octadecenoyl-ACP Isomers (Identification of a Petroselinoyl-ACP Thioesterase in Umbelliferae).

    PubMed Central

    Dormann, P.; Frentzen, M.; Ohlrogge, J. B.

    1994-01-01

    This study was designed to address the question: How specific for double bond position and conformation are plant enzymes that act on oleoyl-acyl carrier protein (ACP)? Octadecenoyl-ACPs with cis double bonds at positions [delta]6, [delta]7, [delta]8, [delta]9, [delta]10, [delta]11, or [delta]12 and elaidyl (18:1[delta]9trans)-ACP were synthesized and used to characterize the substrate specificity of the acyl-ACP thioesterase and acyl-ACP:sn-glycerol-3-phosphate acyltransferase. The two enzymes were found to be specific for the [delta]9 position of the double bond. The thioesterase was highly specific for the [delta]9 cis conformation, but the transferase was almost equally active with the cis and the trans isomer of 18:1[delta]9-ACP. In plants such as the Umbelliferae species coriander (Coriandrum sativum L.) that accumulate petroselinic acid (18:1[delta]6cis) in their seed triacylglycerols, a high petroselinoyl-ACP thioesterase activity was found in addition to the oleoyl-ACP thioesterase. The two activities could be separated by anion-exchange chromatography, indicating that the petroselinoyl-ACP thioesterase is represented by a distinct polypeptide. PMID:12232130

  18. Identification of seven novel virulence genes from Xanthomonas citri subsp. citri by Tn5-based random mutagenesis.

    PubMed

    Song, Xue; Guo, Jing; Ma, Wen-xiu; Ji, Zhi-yuan; Zou, Li-fang; Chen, Gong-you; Zou, Hua-song

    2015-05-01

    To identify novel virulence genes, a mutant library of Xanthomonas citri subsp. citri 29-1 was produced using EZ-Tn5 transposon and the mutants were inoculated into susceptible grapefruit. Forty mutants with altered virulence phenotypes were identified. Nine of the mutants showed a complete loss of citrus canker induction, and the other 31 mutants resulted in attenuated canker symptoms. Southern blot analysis revealed that each of the mutants carried a single copy of Tn5. The flanking sequence was identified by plasmid rescue and 18 different ORFs were identified in the genome sequence. Of these 18 ORFs, seven had not been previously associated with the virulence of X. citri subsp. citri and were therefore confirmed by complementation analysis. Real-time PCR analysis showed that the seven genes were upregulated when the bacteria were grown in citrus plants, suggesting that the expression of these genes was essential for canker development. PMID:25935304

  19. Development of markers for Delta9-Stearoyl-ACP-Desaturase (SAD) to screen for cold acclimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Delta 9-Stearoyl-acyl carrier protein (ACP) desaturase (SAD) is an important enzyme of fatty acid biosynthesis in higher plants. Located in the plastid stroma, SAD catalyzes the desaturation of stearoyl-ACP to oleyl-ACP. SAD plays a key role in determining the ratio of saturated fatty acids to unsat...

  20. Modeling holo-ACP:DH and holo-ACP:KR complexes of modular polyketide synthases: a docking and molecular dynamics study

    PubMed Central

    2012-01-01

    Background Modular polyketide synthases are multifunctional megasynthases which biosynthesize a variety of secondary metabolites using various combinations of dehydratase (DH), ketoreductase (KR) and enoyl-reductase (ER) domains. During the catalysis of various reductive steps these domains act on a substrate moiety which is covalently attached to the phosphopantetheine (P-pant) group of the holo-Acyl Carrier Protein (holo-ACP) domain, thus necessitating the formation of holo-ACP:DH and holo-ACP:KR complexes. Even though three dimensional structures are available for DH, KR and ACP domains, no structures are available for DH or KR domains in complex with ACP or substrate moieties. Since Ser of holo-ACP is covalently attached to a large phosphopantetheine group, obtaining complexes involving holo-ACP by standard protein-protein docking has been a difficult task. Results We have modeled the holo-ACP:DH and holo-ACP:KR complexes for identifying specific residues on DH and KR domains which are involved in interaction with ACP, phosphopantetheine and substrate moiety. A novel combination of protein-protein and protein-ligand docking has been used to first model complexes involving apo-ACP and then dock the phosphopantetheine and substrate moieties using covalent connectivity between ACP, phosphopantetheine and substrate moiety as constraints. The holo-ACP:DH and holo-ACP:KR complexes obtained from docking have been further refined by restraint free explicit solvent MD simulations to incorporate effects of ligand and receptor flexibilities. The results from 50 ns MD simulations reveal that substrate enters into a deep tunnel in DH domain while in case of KR domain the substrate binds a shallow surface exposed cavity. Interestingly, in case of DH domain the predicted binding site overlapped with the binding site in the inhibitor bound crystal structure of FabZ, the DH domain from E.Coli FAS. In case of KR domain, the substrate binding site identified by our simulations

  1. PCR-based Detection of Spiroplasma Citri Associated with Citrus Stubborn Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improvements in polymerase chain reaction (PCR) detection of Spiroplasma citri, the causal agent of citrus stubborn disease, made PCR more reliable than culturing for S. citri detection. Primer sequences from the P89 putative adhesin gene, which is present on a plasmid as well as in the S. citri gen...

  2. Genetic variation of Spiroplasma citri populations in California revealed by two genomic loci

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus stubborn disease (CSD), known to be present in California since 1915, was confirmed to be caused by Spiroplasma citri in 1972. Hosts of S. citri include citrus and a wide range of annual weeds, ornamentals and crops such as carrots and sesame. Genetic variation of S. citri in California was e...

  3. PCR-based Detection of Spiroplasma citri Associated with Citrus Stubborn Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    PCR detection of Spiroplasma citri, the causal agent of citrus stubborn disease, was improved using primers based on sequences of the P89 adhesin gene and the P58 putative adhesin multigene of S. citri. PCR was compared with isolation by culturing for detection of S. citri in two 20 A citrus orchar...

  4. A MLVA genotyping scheme for global surveillance of the citrus pathogen Xanthomonas citri pv. citri suggests a worldwide geographical expansion of a single genetic lineage.

    PubMed

    Pruvost, Olivier; Magne, Maxime; Boyer, Karine; Leduc, Alice; Tourterel, Christophe; Drevet, Christine; Ravigné, Virginie; Gagnevin, Lionel; Guérin, Fabien; Chiroleu, Frédéric; Koebnik, Ralf; Verdier, Valérie; Vernière, Christian

    2014-01-01

    MultiLocus Variable number of tandem repeat Analysis (MLVA) has been extensively used to examine epidemiological and evolutionary issues on monomorphic human pathogenic bacteria, but not on bacterial plant pathogens of agricultural importance albeit such tools would improve our understanding of their epidemiology, as well as of the history of epidemics on a global scale. Xanthomonas citri pv. citri is a quarantine organism in several countries and a major threat for the citrus industry worldwide. We screened the genomes of Xanthomonas citri pv. citri strain IAPAR 306 and of phylogenetically related xanthomonads for tandem repeats. From these in silico data, an optimized MLVA scheme was developed to assess the global diversity of this monomorphic bacterium. Thirty-one minisatellite loci (MLVA-31) were selected to assess the genetic structure of 129 strains representative of the worldwide pathological and genetic diversity of X. citri pv. citri. Based on Discriminant Analysis of Principal Components (DAPC), four pathotype-specific clusters were defined. DAPC cluster 1 comprised strains that were implicated in the major geographical expansion of X. citri pv. citri during the 20th century. A subset of 12 loci (MLVA-12) resolved 89% of the total diversity and matched the genetic structure revealed by MLVA-31. MLVA-12 is proposed for routine epidemiological identification of X. citri pv. citri, whereas MLVA-31 is proposed for phylogenetic and population genetics studies. MLVA-31 represents an opportunity for international X. citri pv. citri genotyping and data sharing. The MLVA-31 data generated in this study was deposited in the Xanthomonas citri genotyping database (http://www.biopred.net/MLVA/). PMID:24897119

  5. A MLVA Genotyping Scheme for Global Surveillance of the Citrus Pathogen Xanthomonas citri pv. citri Suggests a Worldwide Geographical Expansion of a Single Genetic Lineage

    PubMed Central

    Boyer, Karine; Leduc, Alice; Tourterel, Christophe; Drevet, Christine; Ravigné, Virginie; Gagnevin, Lionel; Guérin, Fabien; Chiroleu, Frédéric; Koebnik, Ralf; Verdier, Valérie; Vernière, Christian

    2014-01-01

    MultiLocus Variable number of tandem repeat Analysis (MLVA) has been extensively used to examine epidemiological and evolutionary issues on monomorphic human pathogenic bacteria, but not on bacterial plant pathogens of agricultural importance albeit such tools would improve our understanding of their epidemiology, as well as of the history of epidemics on a global scale. Xanthomonas citri pv. citri is a quarantine organism in several countries and a major threat for the citrus industry worldwide. We screened the genomes of Xanthomonas citri pv. citri strain IAPAR 306 and of phylogenetically related xanthomonads for tandem repeats. From these in silico data, an optimized MLVA scheme was developed to assess the global diversity of this monomorphic bacterium. Thirty-one minisatellite loci (MLVA-31) were selected to assess the genetic structure of 129 strains representative of the worldwide pathological and genetic diversity of X. citri pv. citri. Based on Discriminant Analysis of Principal Components (DAPC), four pathotype-specific clusters were defined. DAPC cluster 1 comprised strains that were implicated in the major geographical expansion of X. citri pv. citri during the 20th century. A subset of 12 loci (MLVA-12) resolved 89% of the total diversity and matched the genetic structure revealed by MLVA-31. MLVA-12 is proposed for routine epidemiological identification of X. citri pv. citri, whereas MLVA-31 is proposed for phylogenetic and population genetics studies. MLVA-31 represents an opportunity for international X. citri pv. citri genotyping and data sharing. The MLVA-31 data generated in this study was deposited in the Xanthomonas citri genotyping database (http://www.biopred.net/MLVA/). PMID:24897119

  6. 26 CFR 1.401(m)-2 - ACP test.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... determined under § 1.401(m)-2(b)(2)(iv) (as it appeared in the April 1, 2007, edition of 26 CFR part 1). (E... determined under § 1.401(m)-2(b)(2)(vi) (as it appeared in the April 1, 2007, edition of 26 CFR Part 1). If... 26 Internal Revenue 5 2010-04-01 2010-04-01 false ACP test. 1.401(m)-2 Section 1.401(m)-2...

  7. Temperature stress promotes cell division arrest in Xanthomonas citri subsp. citri.

    PubMed

    Sumares, Júlia A P; Morão, Luana Galvão; Martins, Paula M M; Martins, Daniela A B; Gomes, Eleni; Belasque, José; Ferreira, Henrique

    2016-04-01

    Citrus canker is an economically important disease that affects orange production in some of the most important producing areas around the world. It represents a great threat to the Brazilian and North American citriculture, particularly to the states of São Paulo and Florida, which together correspond to the biggest orange juice producers in the world. The etiological agent of this disease is the Gram-negative bacterium Xanthomonas citri subsp. citri (Xcc), which grows optimally in laboratory cultures at ~30°C. To investigate how temperatures differing from 30°C influence the development of Xcc, we subjected the bacterium to thermal stresses, and afterward scored its recovery capability. In addition, we analyzed cell morphology and some markers of essential cellular processes that could indicate the extent of the heat-induced damage. We found that the exposure of Xcc to 37°C for a period of 6 h led to a cell cycle arrest at the division stage. Thermal stress might have also interfered with the DNA replication and/or the chromosome segregation apparatuses, since cells displayed an increased number of sister origins side-by-side within rods. Additionally, Xcc treated at 37°C was still able to induce citrus canker symptoms, showing that thermal stress did not affect the ability of Xcc to colonize the host citrus. At 40-42°C, Xcc lost viability and became unable to induce disease symptoms in citrus. Our results provide evidence about essential cellular mechanisms perturbed by temperature, and can be potentially explored as a new method for Xanthomonas citri synchronization in cell cycle studies, as well as for the sanitation of plant material. PMID:26663580

  8. A protein expression system for tandem affinity purification in Xanthomonas citri subsp. citri.

    PubMed

    Dantas, Giordanni C; Martins, Paula M M; Martins, Daniela A B; Gomes, Eleni; Ferreira, Henrique

    2016-01-01

    Citrus canker, caused by the Gram-negative bacterium Xanthomonas citri subsp. citri (Xac), is one of the most devastating diseases to affect citrus crops. There is no treatment for citrus canker; effective control against the spread of Xac is usually achieved by the elimination of affected plants along with that of asymptomatic neighbors. An in depth understanding of the pathogen is the keystone for understanding of the disease; to this effect we are committed to the development of strategies to ease the study of Xac. Genome sequencing and annotation of Xac revealed that ∼37% of the genome is composed of hypothetical ORFs. To start a systematic characterization of novel factors encoded by Xac, we constructed integrative-vectors for protein expression specific to this bacterium. The vectors allow for the production of TAP-tagged proteins in Xac under the regulation of the xylose promoter. In this study, we show that a TAP-expression vector, integrated into the amy locus of Xac, does not compromise its virulence. Furthermore, our results also demonstrate that the polypeptide TAP can be overproduced in Xac and purified from the soluble phase of cell extracts. Our results substantiate the use of our vectors for protein expression in Xac thus contributing a novel tool for the characterization of proteins and protein complexes generated by this bacterium in vivo. PMID:26991273

  9. treA Codifies for a Trehalase with Involvement in Xanthomonas citri subsp. citri Pathogenicity.

    PubMed

    Alexandrino, André Vessoni; Goto, Leandro Seiji; Novo-Mansur, Maria Teresa Marques

    2016-01-01

    Citrus canker, caused by the bacterium Xanthomonas citri subsp. citri (Xcc), is a severe disease of citrus. Xcc presents broad spectrum of citrus hosts including economically important species whereas X. fuscans subsp. aurantifolii-type C (XauC) causes a milder disease and only infects Citrus aurantifolia. Trehalase catalyzes hydrolysis of the disaccharide trehalose, a sugar that has been reported to be related to Xcc pathogenicity. We expressed the recombinant gene product and assessed Xcc trehalase structural and kinetics data. The recombinant protein presented 42.7% of secondary structures in α-helix and 13% in β-sheets, no quaternary structure in solution, and Michaelis-Menten constant (KM) of 0.077 mM and Vmax 55.308 μMol glucose.min-1.mg protein-1 for trehalose. A Xcc mutant strain (XccΔtreA) was produced by gene deletion from Xcc genome. Enzymatic activity of trehalase was determined in Xcc, XauC and XccΔtreA cellular lysates, showing the highest values for XauC in in vitro infective condition and no activity for XccΔtreA. Finally, leaves of Citrus aurantifolia infected with XccΔtreA showed much more drenching and necrosis than those infected by wild type Xcc. We concluded that trehalase contributes to alleviate bacterial virulence and that inability for trehalose hydrolysis may promote higher Xcc infectivity. PMID:27611974

  10. Bioactive Organocopper Compound from Pseudomonas aeruginosa Inhibits the Growth of Xanthomonas citri subsp. citri

    PubMed Central

    de Oliveira, Admilton G.; Spago, Flavia R.; Simionato, Ane S.; Navarro, Miguel O. P.; da Silva, Caroline S.; Barazetti, André R.; Cely, Martha V. T.; Tischer, Cesar A.; San Martin, Juca A. B.; de Jesus Andrade, Célia G. T.; Novello, Cláudio R.; Mello, João C. P.; Andrade, Galdino

    2016-01-01

    Citrus canker is a very destructive disease of citrus species. The challenge is to find new compounds that show strong antibiotic activity and low toxicity to plants and the environment. The objectives of the present study were (1) to extract, purify and evaluate the secondary metabolites with antibiotic activity produced by Pseudomonas aeruginosa LV strain in vitro against Xanthomonas citri subsp. citri (strain 306), (2) to determine the potential of semi-purified secondary metabolites in foliar application to control citrus canker under greenhouse conditions, and (3) to identify antibiotic activity in orange leaf mesophyll infected with strain 306, by electron microscopy. Two pure bioactive compounds were isolated, an organocopper antibiotic compound (OAC) and phenazine-1-carboxamide. Phenazine-1-carboxamide did not show any antibiotic activity under the experimental conditions used in this study. The OAC showed a high level of antibiotic activity with a minimum inhibitory concentration of 0.12 μg mL-1. In greenhouse tests for control of citrus canker in orange trees, the semi-purified fraction F3d reduced lesion formation by about 97%. The concentration used was 500 times lower than that for the recommended commercial copper-based product. Electron microscopy showed that F3d altered the exopolysaccharide matrix and caused cell lysis of the pathogen inside the citrus canker lesions. These results suggest that secondary metabolites produced by inducing P. aeruginosa LV strain have a high potential to be used as a bioproduct to control citrus canker. PMID:26903992

  11. Epidemiology of Spiroplasma citri in the Old World.

    PubMed

    Bove, J M; Fos, A; Lallemand, J

    1987-06-01

    Epidemics of citrus stubborn disease (CSD) have been known in the Mediterranean citrus-growing areas as early as 1928. One such outbreak of stubborn disease occurred around 1980 in newly established citrus nurseries on the Syrian coast. Natural transmission of Spiroplasma citri could be shown to be involved. Enzyme-linked immunosorbent assay (ELISA) and culture of S. citri were used to detect the presence of S. citri in leafhoppers. Over 50 leafhopper species were submitted to these analyses, not only in Syria but also in Morocco and France (Corsica) from 1978 to 1985. Neoaliturus (Circulifer) haematoceps was the only species found to harbor the spiroplasma in Morocco, Syria and France (Corsica). Leafhoppers of this species were collected in Corsica, raised in Bordeaux and shown to be vectors of S. citri. The search for N. haematoceps in nature has revealed that Salsola kali (Chenopodiacae) is a favored host plant of this leafhopper. This plant has a wide geographical distribution. In Iran, for instance, it is well known, and grows close to sugar beet and citrus-growing areas. In such areas, sugar beet is known to be infected by curly top virus, and citrus by CSD. N. haematoceps is a vector of both of these diseases. N. tenellus, the vector of S. citri in the USA, is present in the Mediterranean area, but in view of its paucity it does not seem to be a major vector there. In Iran, even though less abundant than N. haematoceps, it could play a role in S. citri transmission. PMID:3312105

  12. Temporal Transcription Profiling of Sweet Orange in Response to PthA4-Mediated Xanthomonas citri subsp. citri Infection.

    PubMed

    Hu, Yang; Duan, Shuo; Zhang, Yunzeng; Shantharaj, Deepak; Jones, Jeffrey B; Wang, Nian

    2016-05-01

    Citrus canker, caused by Xanthomonas citri subsp. citri, is a devastating disease of most commercial citrus varieties. In our previous study, we analyzed the transcriptional response of 'Valencia' sweet orange to X. citri subsp. citri wild-type and pthA4 mutant infection at 48 h postinoculation (hpi). Using microarray analysis, two PthA4 targets, CsLOB1 and CsSWEET1, were identified. We have shown that PthA4 binds to the effector binding element (EBE) of CsLOB1 and activates gene expression of this susceptibility gene. However, how PthA4 modulates host genes at different stages of infection remains to be determined. In this study, we compared the transcriptional profiles between citrus leaf tissue inoculated with Xcc306 and those inoculated with a pthA4-deletion mutant strain (Xcc306∆pthA4) at 6, 48, and 120 hpi. At both 48 and 120 hpi, the PthA4-mediated infection significantly upregulated expression of a variety of genes involved in cell-wall degradation and modification, DNA packaging, G-protein, protein synthesis, sucrose metabolism, and cell division functions, while the downregulated genes were mainly enriched in photosynthesis, transport, secondary metabolism, cytochrome P450, and various plant defense-associated mechanisms. To validate microarray results, gene expression of 26 genes representing genes associated with cell-wall-associated, immunity system, and carbohydrate metabolism was confirmed using quantitative reverse-transcription polymerase chain reaction. Expression patterns of these genes at 48 and 120 hpi were consistent with the microarray results. We also identified putative EBE for PthA4 (EBEPthA4) in the promoter regions of multiple genes upregulated by PthA4, to which PthA4 might bind directly to control their gene expression. Our study provided a dynamic picture of citrus genes regulated by PthA4 during the X. citri subsp. citri infection of citrus leaves at different stages. This study will be useful in further understanding the virulence

  13. SCREENING CITRUS GERMPLASM FOR RESISTANCE TO XANTHOMONAS ANONOPODIS PV. CITRI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus bacterial canker (causal agent Xanthomonas axonopodis pv. citri (Xac)) is a serious threat to the citrus industry. Currently there are no effective means to control citrus canker. Our objective was to determine the resistance of selected Citrus species, citrus hybrids, and citrus relatives to...

  14. Genome Sequence of Xanthomonas citri pv. mangiferaeindicae Strain LMG 941

    PubMed Central

    Midha, Samriti; Ranjan, Manish; Sharma, Vikas; Pinnaka, Anil Kumar

    2012-01-01

    We report the 5.1-Mb genome sequence of Xanthomonas citri pv. mangiferaeindicae strain LMG 941, the causal agent of bacterial black spot in mango. Apart from evolutionary studies, the draft genome will be a valuable resource for the epidemiological studies and quarantine of this phytopathogen. PMID:22582385

  15. Functional Characterization of a LOV-Histidine Kinase Photoreceptor from Xanthomonas citri subsp. citri.

    PubMed

    Kraiselburd, Ivana; Gutt, Alexander; Losi, Aba; Gärtner, Wolfgang; Orellano, Elena G

    2015-01-01

    The blue-light (BL) absorbing protein Xcc-LOV from Xanthomonas citri subsp. citri is composed of a LOV-domain, a histidine kinase (HK) and a response regulator. Spectroscopic characterization of Xcc-LOV identified intermediates and kinetics of the protein's photocycle. Measurements of steady state and time-resolved fluorescence allowed determination of quantum yields for triplet (ΦT  = 0.68 ± 0.03) and photoproduct formation (Φ390  = 0.46 ± 0.05). The lifetime for triplet decay was determined as τT  = 2.4-2.8 μs. Fluorescence of tryptophan and tyrosine residues was unchanged upon light-to-dark conversion, emphasizing the absence of significant conformational changes. Photochemistry was blocked upon cysteine C76 (C76S) mutation, causing a seven-fold longer lifetime of the triplet state (τT  = 16-18.5 μs). Optoacoustic spectroscopy yielded the energy content of the triplet state. Interestingly, Xcc-LOV did not undergo the volume contraction reported for other LOV domains within the observation time window, although the back-conversion into the dark state was accompanied by a volume expansion. A radioactivity-based enzyme function assay revealed a larger HK activity in the lit than in the dark state. The C76S mutant showed a still lower enzyme function, indicating the dark state activity being corrupted by a remaining portion of the long-lived lit state. PMID:26172037

  16. Non-Host Defense Response in a Novel Arabidopsis-Xanthomonas citri subsp. citri Pathosystem

    PubMed Central

    An, Chuanfu; Mou, Zhonglin

    2012-01-01

    Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is one of the most destructive diseases of citrus. Progress of breeding citrus canker-resistant varieties is modest due to limited resistant germplasm resources and lack of candidate genes for genetic manipulation. The objective of this study is to establish a novel heterologous pathosystem between Xcc and the well-established model plant Arabidopsis thaliana for defense mechanism dissection and resistance gene identification. Our results indicate that Xcc bacteria neither grow nor decline in Arabidopsis, but induce multiple defense responses including callose deposition, reactive oxygen species and salicylic aicd (SA) production, and defense gene expression, indicating that Xcc activates non-host resistance in Arabidopsis. Moreover, Xcc-induced defense gene expression is suppressed or attenuated in several well-characterized SA signaling mutants including eds1, pad4, eds5, sid2, and npr1. Interestingly, resistance to Xcc is compromised only in eds1, pad4, and eds5, but not in sid2 and npr1. However, combining sid2 and npr1 in the sid2npr1 double mutant compromises resistance to Xcc, suggesting genetic interactions likely exist between SID2 and NPR1 in the non-host resistance against Xcc in Arabidopsis. These results demonstrate that the SA signaling pathway plays a critical role in regulating non-host defense against Xcc in Arabidopsis and suggest that the SA signaling pathway genes may hold great potential for breeding citrus canker-resistant varieties through modern gene transfer technology. PMID:22299054

  17. Short distance dispersal of splashed bacteria of Xanthomonas citri subsp. citri from canker-infected grapefruit tree canopies in turbulent wind

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp citri [Xcc]) can result in yield loss and market restrictions. The pathogen is dispersed in rain splash and spread is promoted by wind. The goal of this study was to gain some insight into the behavior of the downwind plume of Xcc from ~1.5 m-tall canker-affect...

  18. The epidemiological significance of post-packinghouse survival of Xanthomonas citri ssp. citri for dissemination of Asiatic citrus canker via infected fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The risk of introduction of Xanthomonas citri spp. citri (Xcc) to new, unaffected citrus producing areas is a major concern for those citrus industries attempting to remain free of citrus canker. Citrus fruit, as a potential pathway for Xcc to enter and become established in these areas, is assumed...

  19. The effect of wind on dispersal of splash-borne Xanthomonas citri subsp citri at different heights and distances downwind of canker-infected grapefruit trees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas citri subsp citri (Xcc), which causes citrus canker, is a major pathogen of grapefruit and other canker-susceptible citrus species and cultivars grown in Florida and elsewhere. It is dispersed by rain splash, and wind promotes the dispersal of the pathogen. The aim of this study was to e...

  20. Processes involved in the dispersal of Xanthomonas citri pv. citri from canker-infectd citrus canopies, and in the infection of citrus foliage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) is now considered endemic in Florida, and epidemics result in yield loss and market penalties both in Florida, and elsewhere where the pathogen occurs, and susceptible citrus is cultivated. The bacterium is dispersed in rain splash, and storms wit...

  1. Processess involved in the dispersal of Xanthomonas citri pv. citri from canker-infected citrus canopies, and in the infection of citrus foliage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) is now considered endemic in Florida, and epidemics result in yield loss and market penalties both in Florida and elsewhere, where the pathogen occurs and susceptible citrus is cultivated. The bacterium is dispersed in rain splash, and storms with...

  2. Wind speed effects on the quantity of Xanthomonas citri subsp. citri dispersed downwind from canopies of grapefruit trees infected with citrus canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The epidemic of citrus canker (Xanthomonas citri subsp. citri, Xcc) in Florida continues to expand since termination of the eradication program in 2006. Storms are known to be associated with disease spread, but little information exists on the interaction of fundamental physical and biological proc...

  3. Bismerthiazol Inhibits Xanthomonas citri subsp. citri Growth and Induces Differential Expression of Citrus Defense-Related Genes.

    PubMed

    Yu, Xiaoyue; Armstrong, Cheryl M; Zhou, Mingguo; Duan, Yongping

    2016-07-01

    Citrus canker, caused by Xanthomonas citri ssp. citri, is a serious disease that causes substantial economic losses to the citrus industry worldwide. The bactericide bismerthiazol has been used to control rice bacterial blight (X. oryzae pv. oryzae). In this paper, we demonstrate that bismerthiazol can effectively control citrus canker by both inhibiting the growth of X. citri ssp. citri and triggering the plant's host defense response through the expression of several pathogenesis-related genes (PR1, PR2, CHI, and RpRd1) and the nonexpresser of PR genes (NPR1, NPR2, and NPR3) in 'Duncan' grapefruit, especially at early treatment times. In addition, we found that bismerthiazol induced the expression of the marker genes CitCHS and CitCHI in the flavonoid pathway and the PAL1 (phenylalanine ammonia lyase 1) gene in the salicylic acid (SA) biosynthesis pathway at different time points. Moreover, bismerthiazol also induced the expression of the priming defense-associated gene AZI1. Taken together, these results indicate that the induction of the defense response in 'Duncan' grapefruit by bismerthiazol may involve the SA signaling pathway and the priming defense and that bismerthiazol may serve as an alternative to copper bactericides for the control of citrus canker. PMID:26882850

  4. Phylogenetic and experimental characterization of an acyl-ACP thioesterase family reveals significant diversity in enzymatic specificity and activity

    PubMed Central

    2011-01-01

    Background Acyl-acyl carrier protein thioesterases (acyl-ACP TEs) catalyze the hydrolysis of the thioester bond that links the acyl chain to the sulfhydryl group of the phosphopantetheine prosthetic group of ACP. This reaction terminates acyl chain elongation of fatty acid biosynthesis, and in plant seeds it is the biochemical determinant of the fatty acid compositions of storage lipids. Results To explore acyl-ACP TE diversity and to identify novel acyl ACP-TEs, 31 acyl-ACP TEs from wide-ranging phylogenetic sources were characterized to ascertain their in vivo activities and substrate specificities. These acyl-ACP TEs were chosen by two different approaches: 1) 24 TEs were selected from public databases on the basis of phylogenetic analysis and fatty acid profile knowledge of their source organisms; and 2) seven TEs were molecularly cloned from oil palm (Elaeis guineensis), coconut (Cocos nucifera) and Cuphea viscosissima, organisms that produce medium-chain and short-chain fatty acids in their seeds. The in vivo substrate specificities of the acyl-ACP TEs were determined in E. coli. Based on their specificities, these enzymes were clustered into three classes: 1) Class I acyl-ACP TEs act primarily on 14- and 16-carbon acyl-ACP substrates; 2) Class II acyl-ACP TEs have broad substrate specificities, with major activities toward 8- and 14-carbon acyl-ACP substrates; and 3) Class III acyl-ACP TEs act predominantly on 8-carbon acyl-ACPs. Several novel acyl-ACP TEs act on short-chain and unsaturated acyl-ACP or 3-ketoacyl-ACP substrates, indicating the diversity of enzymatic specificity in this enzyme family. Conclusion These acyl-ACP TEs can potentially be used to diversify the fatty acid biosynthesis pathway to produce novel fatty acids. PMID:21831316

  5. Walking Together: A Narrative/Pastoral Approach to the ACPE Accreditation Site Visit

    ERIC Educational Resources Information Center

    Oertli, Karrie

    2010-01-01

    Walking together is a strong theme in religious literature: God companions persons, and persons companion one another. All share and hear stories in that action. The Association for Clinical Pastoral Education, Inc. (ACPE) began to walk together in 1967, as it gathered four organizations into one. ACPE has grown and changed, becoming world's…

  6. The mitochondrial acyl carrier protein (ACP) coordinates mitochondrial fatty acid synthesis with iron sulfur cluster biogenesis

    PubMed Central

    Van Vranken, Jonathan G; Jeong, Mi-Young; Wei, Peng; Chen, Yu-Chan; Gygi, Steven P; Winge, Dennis R; Rutter, Jared

    2016-01-01

    Mitochondrial fatty acid synthesis (FASII) and iron sulfur cluster (FeS) biogenesis are both vital biosynthetic processes within mitochondria. In this study, we demonstrate that the mitochondrial acyl carrier protein (ACP), which has a well-known role in FASII, plays an unexpected and evolutionarily conserved role in FeS biogenesis. ACP is a stable and essential subunit of the eukaryotic FeS biogenesis complex. In the absence of ACP, the complex is destabilized resulting in a profound depletion of FeS throughout the cell. This role of ACP depends upon its covalently bound 4’-phosphopantetheine (4-PP)-conjugated acyl chain to support maximal cysteine desulfurase activity. Thus, it is likely that ACP is not simply an obligate subunit but also exploits the 4-PP-conjugated acyl chain to coordinate mitochondrial fatty acid and FeS biogenesis. DOI: http://dx.doi.org/10.7554/eLife.17828.001 PMID:27540631

  7. The mitochondrial acyl carrier protein (ACP) coordinates mitochondrial fatty acid synthesis with iron sulfur cluster biogenesis.

    PubMed

    Van Vranken, Jonathan G; Jeong, Mi-Young; Wei, Peng; Chen, Yu-Chan; Gygi, Steven P; Winge, Dennis R; Rutter, Jared

    2016-01-01

    Mitochondrial fatty acid synthesis (FASII) and iron sulfur cluster (FeS) biogenesis are both vital biosynthetic processes within mitochondria. In this study, we demonstrate that the mitochondrial acyl carrier protein (ACP), which has a well-known role in FASII, plays an unexpected and evolutionarily conserved role in FeS biogenesis. ACP is a stable and essential subunit of the eukaryotic FeS biogenesis complex. In the absence of ACP, the complex is destabilized resulting in a profound depletion of FeS throughout the cell. This role of ACP depends upon its covalently bound 4'-phosphopantetheine (4-PP)-conjugated acyl chain to support maximal cysteine desulfurase activity. Thus, it is likely that ACP is not simply an obligate subunit but also exploits the 4-PP-conjugated acyl chain to coordinate mitochondrial fatty acid and FeS biogenesis. PMID:27540631

  8. Xylan utilization regulon in Xanthomonas citri pv. citri Strain 306: gene expression and utilization of oligoxylosides.

    PubMed

    Chow, V; Shantharaj, D; Guo, Y; Nong, G; Minsavage, G V; Jones, J B; Preston, J F

    2015-03-01

    Xanthomonas citri pv. citri strain 306 (Xcc306), a causative agent of citrus canker, produces endoxylanases that catalyze the depolymerization of cell wall-associated xylans. In the sequenced genomes of all plant-pathogenic xanthomonads, genes encoding xylanolytic enzymes are clustered in three adjacent operons. In Xcc306, these consecutive operons contain genes encoding the glycoside hydrolase family 10 (GH10) endoxylanases Xyn10A and Xyn10C, the agu67 gene, encoding a GH67 α-glucuronidase (Agu67), the xyn43E gene, encoding a putative GH43 α-l-arabinofuranosidase, and the xyn43F gene, encoding a putative β-xylosidase. Recombinant Xyn10A and Xyn10C convert polymeric 4-O-methylglucuronoxylan (MeGXn) to oligoxylosides methylglucuronoxylotriose (MeGX3), xylotriose (X3), and xylobiose (X2). Xcc306 completely utilizes MeGXn predigested with Xyn10A or Xyn10C but shows little utilization of MeGXn. Xcc306 with a deletion in the gene encoding α-glucuronidase (Xcc306 Δagu67) will not utilize MeGX3 for growth, demonstrating the role of Agu67 in the complete utilization of GH10-digested MeGXn. Preferential growth on oligoxylosides compared to growth on polymeric MeGXn indicates that GH10 xylanases, either secreted by Xcc306 in planta or produced by the plant host, generate oligoxylosides that are processed by Xyn10 xylanases and Agu67 residing in the periplasm. Coordinate induction by oligoxylosides of xyn10, agu67, cirA, the tonB receptor, and other genes within these three operons indicates that they constitute a regulon that is responsive to the oligoxylosides generated by the action of Xcc306 GH10 xylanases on MeGXn. The combined expression of genes in this regulon may allow scavenging of oligoxylosides derived from cell wall deconstruction, thereby contributing to the tissue colonization and/or survival of Xcc306 and, ultimately, to plant disease. PMID:25595763

  9. Unravelling potential virulence factor candidates in Xanthomonas citri. subsp. citri by secretome analysis

    PubMed Central

    Ferro, Jesus A.; Soares, Marcia R.R.; Laia, Marcelo L.; de Oliveira, Julio C.F.; Ferro, Maria Ines T.

    2016-01-01

    Citrus canker is a major disease affecting citrus production in Brazil. It’s mainly caused by Xanthomonas citri subsp. citri strain 306 pathotype A (Xac). We analysed the differential expression of proteins secreted by wild type Xac and an asymptomatic mutant for hrpB4 (ΔhrpB4) grown in Nutrient Broth (NB) and a medium mimicking growth conditions in the plant (XAM1). This allowed the identification of 55 secreted proteins, of which 37 were secreted by both strains when cultured in XAM1. In this secreted protein repertoire, the following stand out: Virk, Polyphosphate-selective porin, Cellulase, Endoglucanase, Histone-like protein, Ribosomal proteins, five hypothetical proteins expressed only in the wild type strain, Lytic murein transglycosylase, Lipoprotein, Leucyl-tRNA synthetase, Co-chaperonin, Toluene tolerance, C-type cytochrome biogenesis membrane protein, Aminopeptidase and two hypothetical proteins expressed only in the ΔhrpB4 mutant. Furthermore, Peptidoglycan-associated outer membrane protein, Regulator of pathogenicity factor, Outer membrane proteins, Endopolygalacturonase, Chorismate mutase, Peptidyl-prolyl cis-trans isomerase and seven hypothetical proteins were detected in both strains, suggesting that there was no relationship with the secretion mediated by the type III secretory system, which is not functional in the mutant strain. Also worth mentioning is the Elongation factor Tu (EF-Tu), expressed only the wild type strain, and Type IV pilus assembly protein, Flagellin (FliC) and Flagellar hook-associated protein, identified in the wild-type strain secretome when grown only in NB. Noteworthy, that FliC, EF-Tu are classically characterized as PAMPs (Pathogen-associated molecular patterns), responsible for a PAMP-triggered immunity response. Therefore, our results highlight proteins potentially involved with the virulence. Overall, we conclude that the use of secretome data is a valuable approach that may bring more knowledge of the biology of

  10. Improved real-time PCR diagnosis of citrus stubborn disease by targeting prophage genes of Spiroplasma citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spiroplasma citri is a phloem-limited bacterium causing citrus stubborn disease (CSD). Isolation and culturing of S. citri is difficult and time consuming. Current detection methods use polymerase chain reaction (PCR) assays with primers developed from sequences of S. citri house-keeping genes. In c...

  11. Citrus Stubborn Severity is Associated with Spiroplasma Citri Titer but Not with Bacterial Genotype.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of citrus stubborn disease (CSD), caused by Spiroplasma citri, on citrus production is associated with symptom severity of infected citrus trees. To assess whether symptom severity was associated with spiroplasma titer in the plant, 58 S. citri strains were cultivated from severely and mi...

  12. Effects of postharvest treatments on recovery of Xanthomonas citrisubsp. citri from infected grapefruit leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies were conducted to evaluate treatments to reduce recovery of Xanthomonas citri subsp. citri (Xcc) in infected grapefruit leaves. To investigate effects of temperature (0, 10, 40, and 50°C), disinfectant (none or Pro-San), and treatment duration (0, 2, 10, and 20 min) on recovery of Xcc in vit...

  13. First report of citrus canker caused by Xanthomonas citri in Somalia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas citri, causal agent of citrus canker, has been reported in several countries in Africa, but not Somalia. During 2006 and 2007, hyperplasia-type lesions, often surrounded by a water-soaked margin and yellow halo, typical of citrus canker caused by X. citri, were found on 8-10 year-old gr...

  14. Comparison of Droplet Digital PCR and Quantitative PCR Assays for Quantitative Detection of Xanthomonas citri Subsp. citri.

    PubMed

    Zhao, Yun; Xia, Qingyan; Yin, Youping; Wang, Zhongkang

    2016-01-01

    Droplet digital polymerase chain reaction (ddPCR) is a novel molecular biology technique providing absolute quantification of target nucleic acids without the need for an external calibrator. Despite its emerging applications in medical diagnosis, there are few reports of its use for the detection of plant pathogens. This work was designed to assess the diagnosis potential of the ddPCR for absolute quantitative detection of Xanthomonas citri subsp. citri, a quarantine plant pathogenic bacterium that causes citrus bacterial canker in susceptible Citrus species. We transferred an established quantitative PCR (qPCR) assay for citrus bacterial canker diagnosis directly to the ddPCR format and compared the performance of the two methods. The qPCR assay has a broader dynamic range compared to the ddPCR assay and the ddPCR assay has a significantly higher degree of sensitivity compared to the qPCR assay. The influence of PCR inhibitors can be reduced considerably in the ddPCR assay because the collection of end-point fluorescent signals and the counting of binomial events (positive or negative droplets) are associated with a Poisson algorithm. The ddPCR assay also shows lower coefficient of variation compared to the qPCR assay especially in low target concentration. The linear association of the measurements by ddPCR and qPCR assays is strong (Pearson correlation = 0.8633; P<0.001). Receiver operating characteristic analysis indicates the ddPCR methodology is a more robust approach for diagnosis of citrus bacterial canker. In summary, the results demonstrated that the ddPCR assay has the potential for the quantitative detection of X. citri subsp. citri with high precision and accuracy as compared with the results from qPCR assay. Further studies are required to evaluate and validate the value of ddPCR technology in the diagnosis of plant disease and quarantine applications. PMID:27427975

  15. Comparison of Droplet Digital PCR and Quantitative PCR Assays for Quantitative Detection of Xanthomonas citri Subsp. citri

    PubMed Central

    Yin, Youping; Wang, Zhongkang

    2016-01-01

    Droplet digital polymerase chain reaction (ddPCR) is a novel molecular biology technique providing absolute quantification of target nucleic acids without the need for an external calibrator. Despite its emerging applications in medical diagnosis, there are few reports of its use for the detection of plant pathogens. This work was designed to assess the diagnosis potential of the ddPCR for absolute quantitative detection of Xanthomonas citri subsp. citri, a quarantine plant pathogenic bacterium that causes citrus bacterial canker in susceptible Citrus species. We transferred an established quantitative PCR (qPCR) assay for citrus bacterial canker diagnosis directly to the ddPCR format and compared the performance of the two methods. The qPCR assay has a broader dynamic range compared to the ddPCR assay and the ddPCR assay has a significantly higher degree of sensitivity compared to the qPCR assay. The influence of PCR inhibitors can be reduced considerably in the ddPCR assay because the collection of end-point fluorescent signals and the counting of binomial events (positive or negative droplets) are associated with a Poisson algorithm. The ddPCR assay also shows lower coefficient of variation compared to the qPCR assay especially in low target concentration. The linear association of the measurements by ddPCR and qPCR assays is strong (Pearson correlation = 0.8633; P<0.001). Receiver operating characteristic analysis indicates the ddPCR methodology is a more robust approach for diagnosis of citrus bacterial canker. In summary, the results demonstrated that the ddPCR assay has the potential for the quantitative detection of X. citri subsp. citri with high precision and accuracy as compared with the results from qPCR assay. Further studies are required to evaluate and validate the value of ddPCR technology in the diagnosis of plant disease and quarantine applications. PMID:27427975

  16. Compatibility of Isaria fumosorosea (Hypocreales: Cordycipitaceae) Blastospores with Agricultural Chemicals Used for Management of the Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae).

    PubMed

    Avery, Pasco B; Pick, David A; Aristizábal, Luis F; Kerrigan, James; Powell, Charles A; Rogers, Michael E; Arthurs, Steven P

    2013-01-01

    Biorational insecticides are being increasingly emphasized for inclusion in integrated pest management programs for invasive insects. The entomopathogenic fungus, Isaria fumosorosea, can be used to help manage the Asian citrus psyllid with minimal impact on beneficial arthropods, but its effectiveness may be compromised by agrochemicals used to control concurrent arthropod pests and diseases. We evaluated the compatibility of I. fumosorosea blastospores with a range of spray oils and copper-based fungicides registered for use in citrus groves. Results of laboratory and greenhouse tests showed a range of responses of the fungus to the different materials, including compatibility and incompatibility. Overall, I. fumosorosea growth in vitro was reduced least by petroleum-based materials and most by botanical oils and borax, and some of the copper-based fungicides, suggesting that tank mixing of I. fumosorosea with these latter products should be avoided. However, equivalent negative effects of test materials on fungal pathogenicity were not always observed in tests with adult psyllids. We hypothesize that some oils enhanced adherence of blastospores to the insect cuticle, overcoming negative impacts on germination. Our data show that care should be taken in selecting appropriate agrochemicals for tank-mixing with commercial formulations of entomopathogenic fungi for management of citrus pests. The prospects of using I. fumosorosea for managing the invasive Asian citrus psyllid and other citrus pests are discussed. PMID:26462531

  17. Compatibility of Isaria fumosorosea (Hypocreales: Cordycipitaceae) Blastospores with Agricultural Chemicals Used for Management of the Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae)

    PubMed Central

    Avery, Pasco B.; Pick, David A.; Aristizábal, Luis F.; Kerrigan, James; Powell, Charles A.; Rogers, Michael E.; Arthurs, Steven P.

    2013-01-01

    Biorational insecticides are being increasingly emphasized for inclusion in integrated pest management programs for invasive insects. The entomopathogenic fungus, Isaria fumosorosea, can be used to help manage the Asian citrus psyllid with minimal impact on beneficial arthropods, but its effectiveness may be compromised by agrochemicals used to control concurrent arthropod pests and diseases. We evaluated the compatibility of I. fumosorosea blastospores with a range of spray oils and copper-based fungicides registered for use in citrus groves. Results of laboratory and greenhouse tests showed a range of responses of the fungus to the different materials, including compatibility and incompatibility. Overall, I. fumosorosea growth in vitro was reduced least by petroleum-based materials and most by botanical oils and borax, and some of the copper-based fungicides, suggesting that tank mixing of I. fumosorosea with these latter products should be avoided. However, equivalent negative effects of test materials on fungal pathogenicity were not always observed in tests with adult psyllids. We hypothesize that some oils enhanced adherence of blastospores to the insect cuticle, overcoming negative impacts on germination. Our data show that care should be taken in selecting appropriate agrochemicals for tank-mixing with commercial formulations of entomopathogenic fungi for management of citrus pests. The prospects of using I. fumosorosea for managing the invasive Asian citrus psyllid and other citrus pests are discussed. PMID:26462531

  18. Biological control of Asian citrus psyllid (Diaphorina citri) in Florida by the parasitoid Tamarixia radiata in urban plantings of orange jasmine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid is an important invasive citrus pest in the United States because it vectors a bacterium responsible for a devastating disease of citrus known as huanglongbing. A parasitoid of the psyllid, Tamarixia radiata (Hymenoptera: Eulophidae), was imported from Southeast Asia and re...

  19. Association of ‘Candidatus Liberibacter asiaticus’, the causal agent of citrus huanglongbing in Murraya paniculata and Diaphorina citri in Thailand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Orange jasmine, Murraya paniculata, is a preferred alternative host for the Asian citrus psyllid, the primary vector of citrus Huanglongbing (HLB) disease caused by ‘Candidatus Liberibacter asiaticus’ (Las). M. paniculata plant samples and psyllids on the Murraya plants from ten diverse geographical...

  20. Diversity of the citrus HLB bacterium, ‘Candidatus Liberibacter asiaticus’, in psyllids (Diaphorina citri) collected from Murraya paniculata and citrus spp. in Thailand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Candidatus Liberibacter asiaticus’ (Las) is a phloem inhabiting bacterium that causes huanglongbing disease (HLB), also known as citrus greening associated with three species of a-Proteobacteria in the genus ‘Candidatus Liberibacter sp’. Prophage is an important genetic element of bacterial genomes...

  1. The push-pull strategy for citrus psyllid control.

    PubMed

    Yan, Huaxue; Zeng, Jiwu; Zhong, Guangyan

    2015-07-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the only natural vector of Candidatus Liberibacter asiaticus that causes citrus huanglongbing (HLB), a most destructive disease of citrus. Currently, no remedial therapy exists for the disease, and so effective control of ACP is very important in curbing the transmission of the disease. The push-pull strategy should be thoroughly explored as an approach to ACP management. This mini-review summarises the current progress towards more effective repellent and attractant chemicals through investigating known repellent and attractive plants. Interactions between ACP and its host plants are also addressed, with emphasis on the possible involvement of the host biochemicals in attracting the insect. Potential ways to increase the effectiveness of the pull-push strategy are briefly discussed. It is expected that the pull-push strategy will be gradually developed following more extensive research. PMID:25256398

  2. Identification of Xanthomonas citri ssp. citri host specificity genes in a heterologous expression host.

    PubMed

    Rybak, Myrian; Minsavage, Gerald V; Stall, Robert E; Jones, Jeffrey B

    2009-03-01

    We provide the first conclusive evidence that Xanthomonas axonopodis pv. citri Asiatic strain (Xac-A) and, in particular, Xac-A(w), a unique citrus canker A strain isolated from Key lime in Wellington, Florida, induces a hypersensitive reaction (HR) in grapefruit leaves. Using the heterologous tomato pathogen X. perforans, as a recipient of the Xac-A(w) genomic library, we identified a 1599-bp open reading frame responsible for HR in grapefruit, but not Key lime, and designated it avrGf1. Xac-A(w)DeltaavrGf1 produced typical, although visibly reduced, citrus canker symptoms (i.e. raised pustules) in grapefruit and typical canker symptoms in Key lime. We also determined that the X. perforans transconjugant carrying an Xac-A(w) hrpG elicited HR in grapefruit and Key lime leaves, and that xopA in X. perforans was partly responsible for HR. Xac-A transconjugants carrying the X. perforans xopA were reduced in ability to grow in grapefruit leaves relative to wild-type Xac-A. The X. perforans xopA appears to be a host-limiting factor. An avrBs3 homologue, which contained 18.5 repeats and induced HR in tomato, was designated avrTaw. This gene, when expressed in a pustule-minus Xac-A(w), did not complement pustule formation; however, pthA(w), a functional pthA homologue, complemented the mutant strain to produce typical pustules in Key lime, but markedly reduced pustules in grapefruit. Both avrBs3 homologues, when expressed in a typical Xac-A strain, resulted in typical citrus canker pustules in grapefruit, indicating that neither homologue suppressed pustule size in grapefruit. Xac-A(w) contains other unidentified factors that suppress development in grapefruit. PMID:19236573

  3. Expression and specificity profile of the major acetate transporter AcpA in Aspergillus nidulans.

    PubMed

    Sá-Pessoa, Joana; Amillis, Sotiris; Casal, Margarida; Diallinas, George

    2015-03-01

    AcpA has been previously characterized as a high-affinity transporter essential for the uptake and use of acetate as sole carbon source in Aspergillus nidulans. Here, we follow the expression profile of AcpA and define its substrate specificity. AcpA-mediated acetate transport is detected from the onset of conidiospore germination, peaks at the time of germ tube emergence, and drops to low basal levels in germlings and young mycelia, where a second acetate transporter is also becoming apparent. AcpA activity also responds to acetate presence in the growth medium, but is not subject to either carbon or nitrogen catabolite repression. Short-chain monocarboxylates (benzoate, formate, butyrate and propionate) inhibit AcpA-mediated acetate transport with apparent inhibition constants (Ki) of 16.89±2.12, 9.25±1.01, 12.06±3.29 and 1.44±0.13mM, respectively. AcpA is also shown not to be directly involved in ammonia export, as proposed for its Saccharomyces cerevisiae homologue Ady2p. In the second part of this work, we search for the unknown acetate transporter expressed in mycelia, and for other transporters that might contribute to acetate uptake. In silico analysis, genetic construction of relevant null mutants, and uptake assays, reveal that the closest AcpA homologue (AN1839), named AcpB, is the 'missing' secondary acetate transporter in mycelia. We also identify two major short-chain carboxylate (lactate, succinate, pyruvate and malate) transporters, named JenA (AN6095) and JenB (AN6703), which however are not involved in acetate uptake. This work establishes a framework for further exploiting acetate and carboxylate transport in filamentous ascomycetes. PMID:25708319

  4. Efficient free fatty acid production in Escherichia coli using plant acyl-ACP thioesterases.

    PubMed

    Zhang, Xiujun; Li, Mai; Agrawal, Arpita; San, Ka-Yiu

    2011-11-01

    Microbial biosynthesis of fatty acid-like chemicals from renewable carbon sources has attracted significant attention in recent years. Free fatty acids can be used as precursors for the production of fuels or chemicals. Free fatty acids can be produced by introducing an acyl-acyl carrier protein thioesterase gene into Escherichia coli. The presence of the acyl-ACP thioesterase will break the fatty acid elongation cycle and release free fatty acid. Depending on their sequence similarity and substrate specificity, class FatA thioesterase is active on unsaturated acyl-ACPs and class FatB prefers saturated acyl group. Different acyl-ACP thioesterases have different degrees of chain length specificity. Although some of these enzymes have been characterized from a number of sources, information on their ability to produce free fatty acid in microbial cells has not been extensively examined until recently. In this study, we examined the effect of the overexpression of acyl-ACP thioesterase genes from Diploknema butyracea, Gossypium hirsutum, Ricinus communis and Jatropha curcas on free fatty acid production. In particular, we are interested in studying the effect of different acyl-ACP thioesterase on the quantities and compositions of free fatty acid produced by an E. coli strain ML103 carrying these constructs. It is shown that the accumulation of free fatty acid depends on the acyl-ACP thioesterase used. The strain carrying the acyl-ACP thioesterase gene from D. butyracea produced approximately 0.2g/L of free fatty acid while the strains carrying the acyl-ACP thioesterase genes from R. communis and J. curcas produced the most free fatty acid at a high level of more than 2.0 g/L at 48 h. These two strains accumulated three major straight chain free fatty acids, C14, C16:1 and C16 at levels about 40%, 35% and 20%, respectively. PMID:22001432

  5. The chain-flipping mechanism of ACP (acyl carrier protein)-dependent enzymes appears universal.

    PubMed

    Cronan, John E

    2014-06-01

    ACPs (acyl carrier proteins) play essential roles in the synthesis of fatty acids, polyketides and non-ribosomal polypeptides. ACP function requires the modification of the protein by attachment of 4'-phosphopantetheine to a conserved serine residue. The phosphopantetheine thiol acts to tether the starting materials and intermediates as their thioesters. ACPs are small highly soluble proteins composed of four α-helices. The helices form a bundle that acts as a hydrophobic sleeve that sequesters the acyl chains and activated thioesters from solvent. However, in the synthesis of fatty acids and complex lipids the enzymes of the pathway must access the thioester and the proximal carbon atoms in order to perform the needed chemistry. How such access is provided without exposure of the acyl chains to solvent has been a longstanding question due to the lack of acyl-ACP-enzyme complexes, a situation generally attributed to the brevity of the interactions of acyl-ACPs with their cognate enzymes. As discussed in the present review the access question has now been answered by four recent crystal structures, each of which shows that the entire acyl chain plus the 4'-phosphopantetheine prosthetic group partitions from the ACP hydrophobic sleeve into a hydrophobic pocket or groove of the enzyme protein, a process termed chain flipping. PMID:24825445

  6. Characterization of soluble acyl-ACP desaturases from Camelina sativa, Macadamia tetraphylla and Dolichandra unguis-cati.

    PubMed

    Rodríguez, Manuel Fernando Rodríguez; Sánchez-García, Alicia; Salas, Joaquín J; Garcés, Rafael; Martínez-Force, Enrique

    2015-04-15

    Acyl-acyl carrier protein (ACP) desaturases (EC 1.14.19.2) are soluble enzymes that catalyse the insertion of a double bond into saturated fatty acid bound in saturated acyl chains bound to ACP in higher plants, producing cis-monounsaturated fatty acids. Three types of soluble acyl-ACP desaturases have been described: Δ(9)-acyl-ACP, Δ(6)-acyl-ACP and Δ(4)-acyl-ACP desaturases, which differ in the substrate specificity and the position in which the double bond is introduced. In the present work, Camelina sativa (CsSAD), Macadamia tetraphylla (MtSAD) and Dolichandra unguis-cati (DuSAD) desaturases were cloned, sequenced and characterized. Single copies of CsSAD, MtSAD and DuSAD with three, one and two different alleles, respectively, were found. The corresponding mature proteins were heterologously expressed in Escherichia coli for biochemical characterization in protein extracts. The recombinant CsSAD enzyme showed 300-fold higher specificity towards 18:0-ACP than 16:0-ACP. Similar profile exhibited MtSAD although the differences in the specificity were lower, around 170-fold higher for 18:0-ACP than 16:0-ACP. Furthermore, DuSAD presented a profile showing preference towards 16:0-ACP against 18:0-ACP, around twice more, being so a Δ(9) palmitoyl-ACP desaturase. Also, we reported the expression profile of CsSAD, which showed the highest levels of expression in expanding tissues that typically are very active in lipid biosynthesis such as developing seed endosperm. Moreover, the possibility to express a new desaturase in C. sativa (oilseed crop that store high levels of oil and is easy to transform) to create a new line rich in short monounsaturated fatty acid is discussed. PMID:25765361

  7. Interaction between infectious diseases and personality traits: ACP1*C as a potential mediator.

    PubMed

    Napolioni, Valerio; Murray, Damian R; Comings, David E; Peters, Warren R; Gade-Andavolu, Radhika; MacMurray, James

    2014-08-01

    In geographical regions characterized by high pathogen prevalence, it has been shown that human populations tend to be characterized by lower levels of extraversion (E) and openness to experience (OtE). According to the "behavioral immune system" hypothesis, the reduction of extraversion and openness levels represents a behavioral defense against infections. Like the 'classical' immune system, the "behavioral immune system" could also be shaped by its underlying genetic background. Previous studies have shown that the *C allele of the ACP1 gene confers increased susceptibility to infectious/parasitic diseases. We hypothesized that carriers of the ACP1*C allele should likewise be associated with reduced E and OtE. We tested this hypothesis using two samples comprised of 153 students from Southern California (Group 1), and 162 female subjects recruited from an executive health program (Group 2), genotyped for ACP1 polymorphism and evaluated by the NEO Five-Factor Inventory (NEO-FFI). ACP1 was significantly associated with E: we found that carriers of ACP1*C showed reduced scores for E (Group 1: β=-4.263, P=0.027; Group 2: β=-8.315, P=0.003; Group 1+Group 2: β=-5.366, P=0.001). Across groups, ACP1 was only marginally associated with OtE. In conclusion, the present study found that the ACP1*C allele, previously associated with an increased vulnerability to infectious/parasitic diseases may also be able to shape behavioral immune defenses by interaction with the level of E. PMID:24933463

  8. Effect of CPP/ACP on initial bioadhesion to enamel and dentin in situ.

    PubMed

    Grychtol, Susann; Basche, Sabine; Hannig, Matthias; Hannig, Christian

    2014-01-01

    The present in situ study investigated the influence of a preparation containing CPP/ACP (caseinphosphopeptide-amorphous calcium phosphate) (GC Tooth mousse) on initial bacterial colonization of enamel and dentin. Therefore, pellicle formation was performed in situ on bovine enamel and dentin specimens fixed to individual upper jaw splints worn by 8 subjects. After 1 min of pellicle formation GC Tooth mousse was used according to manufacturer's recommendations. Rinses with chlorhexidine served as positive controls. Specimens carried without any rinse served as negative controls. After 8 h overnight exposure of the splints, bacterial colonization was quantified by fluorescence microscopy (DAPI and BacLight live/dead staining). Additionally, the colony forming units (CFU) were determined after desorption. Furthermore, the effects on Streptococcus mutans bacteria were tested in vitro (BacLight). There was no significant impact of CPP/ACP on initial bacterial colonization proved with DAPI and BacLight. Determination of CFU showed statistical significance for CPP/ACP to reduce bacterial adherence on enamel. The in vitro investigation indicated no antimicrobial effects for CPP/ACP on Streptococcus mutans suspension. Under the chosen conditions, CPP/ACP (GC Tooth mousse) had no significant impact on initial biofilm formation on dental hard tissues. The tested preparation cannot be recommended for biofilm management. PMID:25386603

  9. Effect of CPP/ACP on Initial Bioadhesion to Enamel and Dentin In Situ

    PubMed Central

    2014-01-01

    The present in situ study investigated the influence of a preparation containing CPP/ACP (caseinphosphopeptide-amorphous calcium phosphate) (GC Tooth mousse) on initial bacterial colonization of enamel and dentin. Therefore, pellicle formation was performed in situ on bovine enamel and dentin specimens fixed to individual upper jaw splints worn by 8 subjects. After 1 min of pellicle formation GC Tooth mousse was used according to manufacturer's recommendations. Rinses with chlorhexidine served as positive controls. Specimens carried without any rinse served as negative controls. After 8 h overnight exposure of the splints, bacterial colonization was quantified by fluorescence microscopy (DAPI and BacLight live/dead staining). Additionally, the colony forming units (CFU) were determined after desorption. Furthermore, the effects on Streptococcus mutans bacteria were tested in vitro (BacLight). There was no significant impact of CPP/ACP on initial bacterial colonization proved with DAPI and BacLight. Determination of CFU showed statistical significance for CPP/ACP to reduce bacterial adherence on enamel. The in vitro investigation indicated no antimicrobial effects for CPP/ACP on Streptococcus mutans suspension. Under the chosen conditions, CPP/ACP (GC Tooth mousse) had no significant impact on initial biofilm formation on dental hard tissues. The tested preparation cannot be recommended for biofilm management. PMID:25386603

  10. Efficacious long-term cooling and freezing of Sapajus apella semen in ACP-118(®).

    PubMed

    Leão, D L; Miranda, S A; Brito, A B; Lima, J S; Santos, R R; Domingues, S F S

    2015-08-01

    The objectives of the present study were to test the effect of coconut water solution (CWS), TES-TRIS and ACP-118(®) on the seminal cooling and cryopreservation of semen from capuchin monkeys (Sapajus apella). Semen was collected from six males by electro-ejaculation, diluted in TES-TRIS, CWS or ACP-118(®), and maintained at 4°C for 28h. Semen was subsequently evaluated (Experiment I) or cryopreserved in the presence of different glycerol concentrations (3%, 5% or 7%) (Experiment II). ACP-118(®) was the preferred extender to preserve sperm motility and viability after 28h incubation at 4°C. Cooled sperm were successfully frozen-thawed in a medium containing 3% glycerol. After thawing, sperm retained the capacity to fertilize oocytes and zygotes were obtained. In conclusion, ACP-118(®) can be effectively and efficiently used as extender for the cooling of S. apella semen. Furthermore, cryopreservation using ACP-118(®) by adding 3% glycerol is suitable to maintain sperm morphology and the capacity of these cells to fertilize in vitro. PMID:26071650

  11. iACP: a sequence-based tool for identifying anticancer peptides

    PubMed Central

    Chen, Wei; Ding, Hui; Feng, Pengmian; Lin, Hao; Chou, Kuo-Chen

    2016-01-01

    Cancer remains a major killer worldwide. Traditional methods of cancer treatment are expensive and have some deleterious side effects on normal cells. Fortunately, the discovery of anticancer peptides (ACPs) has paved a new way for cancer treatment. With the explosive growth of peptide sequences generated in the post genomic age, it is highly desired to develop computational methods for rapidly and effectively identifying ACPs, so as to speed up their application in treating cancer. Here we report a sequence-based predictor called iACP developed by the approach of optimizing the g-gap dipeptide components. It was demonstrated by rigorous cross-validations that the new predictor remarkably outperformed the existing predictors for the same purpose in both overall accuracy and stability. For the convenience of most experimental scientists, a publicly accessible web-server for iACP has been established at http://lin.uestc.edu.cn/server/iACP, by which users can easily obtain their desired results. PMID:26942877

  12. [Constructing an ACP Simulation-Situation Communication Training Program for Patients With Chronic Kidney Disease].

    PubMed

    Chen, Jui-O; Lin, Chiu-Chu

    2016-06-01

    The aging population and changing lifestyles have lead to the increased general risk of chronic kidney disease. Taiwan currently has the highest incidence and prevalence of end-stage renal disease (ESRD) of any country or region in the world. Hemodialysis patients must endure comorbidities and face the uncertainties of death. The best way to achieve a good death is for patients to sign advance care planning (ACP). However, the key factors contributing to low ACP signature rates have been the lack of communication skills and related training among medical staffs. This article explores the dilemma of ACP using an example of chronic kidney disease (CKD) and proposes a theory-based approach to develop a theoretical framework for an ACP simulation-situation communication training program that integrates the simulation situation model, PREPARED model, and scaffolding theory. Readers may use this framework to design ACP simulation-situation communication training programs that conform to their own conditions and then test the effectiveness and feasibility of these programs in clinical settings. PMID:27250964

  13. Presence of Extracellular DNA during Biofilm Formation by Xanthomonas citri subsp. citri Strains with Different Host Range.

    PubMed

    Sena-Vélez, Marta; Redondo, Cristina; Graham, James H; Cubero, Jaime

    2016-01-01

    Xanthomonas citri subsp. citri (Xcc) A strain causes citrus bacterial canker, a serious leaf, fruit and stem spotting disease of several Citrus species. X. alfalfae subsp. citrumelonis (Xac) is the cause of citrus bacterial spot, a minor disease of citrus nursery plants and X. campestris pv. campestris (Xc) is a systemic pathogen that causes black rot of cabbage. Xanthomonas spp. form biofilms in planta that facilitate the host infection process. Herein, the role of extracellular DNA (eDNA) was evaluated in the formation and stabilization of the biofilm matrix at different stages of biofilm development. Fluorescence and light microscopy, as well as DNAse treatments, were used to determine the presence of eDNA in biofilms and bacterial cultures. DNAse treatments of Xcc strains and Xac reduced biofilm formation at the initial stage of development, as well as disrupted preformed biofilm. By comparison, no significant effect of the DNAse was detected for biofilm formation by Xc. DNAse effects on biofilm formation or disruption varied among Xcc strains and Xanthomonas species which suggest different roles for eDNA. Variation in the structure of fibers containing eDNA in biofilms, bacterial cultures, and in twitching motility was also visualized by microscopy. The proposed roles for eDNA are as an adhesin in the early stages of biofilm formation, as an structural component of mature bacterial aggregates, and twitching motility structures. PMID:27248687

  14. HrpM is involved in glucan biosynthesis, biofilm formation and pathogenicity in Xanthomonas citri ssp. citri.

    PubMed

    Malamud, Florencia; Conforte, Valeria P; Rigano, Luciano A; Castagnaro, Atilio P; Marano, María Rosa; Morais do Amaral, Alexandre; Vojnov, Adrian A

    2012-12-01

    Xanthomonas citri ssp. citri (Xcc) is the causal agent of citrus canker. This bacterium develops a characteristic biofilm on both biotic and abiotic surfaces. A biofilm-deficient mutant was identified in a screening of a transposon mutagenesis library of the Xcc 306 strain constructed using the commercial Tn5 transposon EZ-Tn5 Tnp Transposome (Epicentre). Sequence analysis of a mutant obtained in the screening revealed that a single copy of the EZ-Tn5 was inserted at position 446 of hrpM, a gene encoding a putative enzyme involved in glucan synthesis. We demonstrate for the first time that the product encoded by the hrpM gene is involved in β-1,2-glucan synthesis in Xcc. A mutation in hrpM resulted in no disease symptoms after 4 weeks of inoculation in lemon and grapefruit plants. The mutant also showed reduced ability to swim in soft agar and decreased resistance to H(2)O(2) in comparison with the wild-type strain. All defective phenotypes were restored to wild-type levels by complementation with the plasmid pBBR1-MCS containing an intact copy of the hrpM gene and its promoter. These results indicate that the hrpM gene contributes to Xcc growth and adaptation in its host plant. PMID:22738424

  15. Different Transcriptional Response to Xanthomonas citri subsp. citri between Kumquat and Sweet Orange with Contrasting Canker Tolerance

    PubMed Central

    Fu, Xing-Zheng; Gong, Xiao-Qing; Zhang, Yue-Xin; Wang, Yin; Liu, Ji-Hong

    2012-01-01

    Citrus canker disease caused by Xanthomonas citri subsp. citri (Xcc) is one of the most devastating biotic stresses affecting the citrus industry. Meiwa kumquat (Fortunella crassifolia) is canker-resistant, while Newhall navel orange (Citrus sinensis Osbeck) is canker-sensitive. To understand the molecular mechanisms underlying the differences in responses to Xcc, transcriptomic profiles of these two genotypes following Xcc attack were compared by using the Affymetrix citrus genome GeneChip. A total of 794 and 1324 differentially expressed genes (DEGs) were identified as canker-responsive genes in Meiwa and Newhall, respectively. Of these, 230 genes were expressed in common between both genotypes, while 564 and 1094 genes were only significantly expressed in either Meiwa or Newhall. Gene ontology (GO) annotation and Singular Enrichment Analysis (SEA) of the DEGs showed that genes related to the cell wall and polysaccharide metabolism were induced for basic defense in both Meiwa and Newhall, such as chitinase, glucanase and thaumatin-like protein. Moreover, apart from inducing basic defense, Meiwa showed specially upregulated expression of several genes involved in the response to biotic stimulus, defense response, and cation binding as comparing with Newhall. And in Newhall, abundant photosynthesis-related genes were significantly down-regulated, which may be in order to ensure the basic defense. This study revealed different molecular responses to canker disease in Meiwa and Newhall, affording insight into the response to canker and providing valuable information for the identification of potential genes for engineering canker tolerance in the future. PMID:22848606

  16. Mapping and validation of Xanthomonas citri subsp citri genes regulated by putative plant-inducible promoter box (PIP-box).

    PubMed

    Carvalho, F M S; Oliveira, J C F; Laia, M L; Jacob, T R; Ferreira, R M; Ferro, M I T; Tezza, R I D; Zingaretti, S M; Silva, C F; Ferro, J A

    2016-01-01

    Citrus canker, caused by the Gram-negative bacterium Xanthomonas citri subsp citri (Xac), is a major disease affecting citriculture worldwide, because of the susceptibility of the host and the lack of efficient control methods. Previous studies have reported that some genes of phytopathogenic bacteria possess a consensus nucleotide sequence (TTCGC...N15...TTCGC) designated the "plant-inducible-promoter box" (PIP box) located in the promoter region, which is responsible for activating the expression of pathogenicity and virulence factors when the pathogen is in contact with the host plant. In this study, we mapped and investigated the expression of 104 Xac genes associated with the PIP box sequences using a macroarray analysis. Xac gene expression was observed during in vitro (Xac grown for 12 or 20 h in XAM1 induction medium) or in vivo (bacteria grown in orange leaves for 3 to 5 days) infection conditions. Xac grown in non-induction NB liquid medium was used as the control. cDNA was isolated from bacteria grown under the different conditions and hybridized to the macroarray, and 32 genes differentially expressed during the infection period (in vitro or in vivo induction) were identified. The macroarray results were validated for some of the genes through semi-quantitative RT-PCR, and the functionality of the PIP box-containing promoter was demonstrated by activating b-glucuronidase reporter gene activity by the PIP box-containing promoter region during Xac-citrus host interaction. PMID:27173329

  17. Chemical features of Pericarpium Citri Reticulatae and Pericarpium Citri Reticulatae Viride revealed by GC-MS metabolomics analysis.

    PubMed

    Yi, Lunzhao; Dong, Naiping; Liu, Shao; Yi, Zhibiao; Zhang, Yi

    2015-11-01

    This paper introduces a detailed method to apply metabolic profiles conducting on tangerine peels (Citrus reticulata 'Dahongpao') at three maturity stages from July to December. Principal component analysis not only demonstrated the metabolic footprints of tangerine peels during ripening but also revealed the compounds (D-limonene and linalool) that mostly contributed to it. Furthermore, some other characteristic compounds were screened to further reveal the chemical features of Pericarpium Citri Reticulatae (PCR) and Pericarpium Citri Reticulatae Viride (PCRV). In particular, compounds such as 4-carene (r = -0.94), 3-carene (r = -0.91), β-pinene (r = -0.85) and γ-terpinene (r = -0.87) were screened as major components for the pungent smell of PCRV. Geranyl acetate (r = 0.81), farnesyl acetate (r = 0.87) and three alcohols (6-hepten-1-ol, 3-methyl-1-hexanol, 1-octanol) may lead to the pleasant odour of PCR. We therefore propose that the metabolomics analysis focusing on ripening process will be an effective strategy for quality control of closely related herbal medicines. PMID:25976810

  18. Effect of X-irradiation on Citrus Canker Pathogen Xanthomonas citri subsp. citri of Satsuma Mandarin Fruits

    PubMed Central

    Song, Min-A; Park, Jae Sin; Kim, Ki Deok; Jeun, Yong Chull

    2015-01-01

    Citrus canker caused by Xanthomonas citri subsp. citri (Xcc) is one of the most important bacterial diseases of citrus. Because citrus canker is not found in many countries including European Union and Australia, Xcc is strictly regulated in order to prevent its spread. In this study, the effects of X-irradiation on Xcc growth either in the suspension or on the surface of citrus fruits were investigated. The suspension containing 1×107 cfu/ml of Xcc was irradiated with different absorbed doses of X-irradiation ranging from 50 to 400 Gy. The results showed that Xcc was fully dead at 400 Gy of X-irradiation. To determine the effect of X-irradiation on quarantine, the Xcc-inoculated citrus fruits were irradiated with different X-ray doses at which Xcc was completely inhibited by an irradiation dose of 250 Gy. The D10 value for Xcc on citrus fruits was found to be 97 Gy, indicating the possibility of direct application on citrus quarantine without any side sterilizer. Beside, presence of Xcc on the surface of asymptomatic citrus fruits obtained from citrus canker-infected orchards was noted. It indicated that the exporting citrus fruits need any treatment so that Xcc on the citrus fruits should be completely eliminated. Based on these results, ionizing radiation can be considered as an alternative method of eradicating Xcc for export of citrus fruits. PMID:26672670

  19. Presence of Extracellular DNA during Biofilm Formation by Xanthomonas citri subsp. citri Strains with Different Host Range

    PubMed Central

    Sena-Vélez, Marta; Redondo, Cristina; Graham, James H.; Cubero, Jaime

    2016-01-01

    Xanthomonas citri subsp. citri (Xcc) A strain causes citrus bacterial canker, a serious leaf, fruit and stem spotting disease of several Citrus species. X. alfalfae subsp. citrumelonis (Xac) is the cause of citrus bacterial spot, a minor disease of citrus nursery plants and X. campestris pv. campestris (Xc) is a systemic pathogen that causes black rot of cabbage. Xanthomonas spp. form biofilms in planta that facilitate the host infection process. Herein, the role of extracellular DNA (eDNA) was evaluated in the formation and stabilization of the biofilm matrix at different stages of biofilm development. Fluorescence and light microscopy, as well as DNAse treatments, were used to determine the presence of eDNA in biofilms and bacterial cultures. DNAse treatments of Xcc strains and Xac reduced biofilm formation at the initial stage of development, as well as disrupted preformed biofilm. By comparison, no significant effect of the DNAse was detected for biofilm formation by Xc. DNAse effects on biofilm formation or disruption varied among Xcc strains and Xanthomonas species which suggest different roles for eDNA. Variation in the structure of fibers containing eDNA in biofilms, bacterial cultures, and in twitching motility was also visualized by microscopy. The proposed roles for eDNA are as an adhesin in the early stages of biofilm formation, as an structural component of mature bacterial aggregates, and twitching motility structures. PMID:27248687

  20. Advanced spent fuel conditioning process (ACP) progress with respect to remote operation and maintenance

    SciTech Connect

    Lee, Hyo Jik; Lee, Jong Kwang; Park, Byung Suk; Yoon, Ji Sup

    2007-07-01

    Korea Atomic Energy Research Institute (KAERI) has been developing an Advanced Spent Fuel Conditioning Process (ACP) to reduce the volume of spent fuel, and the construction of the ACP facility (ACPF) for a demonstration of its technical feasibility has been completed. In 2006 two inactive demonstrations were performed with simulated fuels in the ACPF. Accompanied by process equipment performance tests, its remote operability and maintainability were also tested during that time. Procedures for remote operation tasks are well addressed in this study and evaluated thoroughly. Also, remote maintenance and repair tasks are addressed regarding some important modules with a high priority order. The above remote handling test's results provided a lot of information such as items to be revised to improve the efficiency of the remote handling tasks. This paper deals with the current status of ACP and the progress of remote handling of ACPF. (authors)

  1. Biofilm formation, epiphytic fitness, and canker development in Xanthomonas axonopodis pv. citri.

    PubMed

    Rigano, Luciano A; Siciliano, Florencia; Enrique, Ramón; Sendín, Lorena; Filippone, Paula; Torres, Pablo S; Qüesta, Julia; Dow, J Maxwell; Castagnaro, Atilio P; Vojnov, Adrián A; Marano, María Rosa

    2007-10-01

    The phytopathogenic bacterium Xanthomonas axonopodis pv. citri is responsible for the canker disease affecting citrus plants throughout the world. Here, we have evaluated the role of bacterial attachment and biofilm formation in leaf colonization during canker development on lemon leaves. Crystal violet staining and confocal laser scanning microscopy analysis of X. axonopodis pv. citri strains expressing the green fluorescent protein were used to evaluate attachment and biofilm formation on abiotic and biotic (leaf) surfaces. Wild-type X. axonopodis pv. citri attached to and formed a complex, structured biofilm on glass in minimal medium containing glucose. Similar attachment and structured biofilm formation also were seen on lemon leaves. An X. axonopodis pv. citri gumB mutant strain, defective in production of the extracellular polysaccharide xanthan, did not form a structured biofilm on either abiotic or biotic surfaces. In addition, the X. axonopodis pv. citri gumB showed reduced growth and survival on leaf surfaces and reduced disease symptoms. These findings suggest an important role for formation of biofilms in the epiphytic survival of X. axonopodis pv. citri prior to development of canker disease. PMID:17918624

  2. Acyl-ACP Substrate Recognition in Burkholderia mallei BmaI1 Acyl-Homoserine Lactone Synthase

    PubMed Central

    2015-01-01

    The acyl-homoserine lactone (AHL) autoinducer mediated quorum sensing regulates virulence in several pathogenic bacteria. The hallmark of an efficient quorum sensing system relies on the tight specificity in the signal generated by each bacterium. Since AHL signal specificity is derived from the acyl-chain of the acyl-ACP (ACP = acyl carrier protein) substrate, AHL synthase enzymes must recognize and react with the native acyl-ACP with high catalytic efficiency while keeping reaction rates with non-native acyl-ACPs low. The mechanism of acyl-ACP substrate recognition in these enzymes, however, remains elusive. In this study, we investigated differences in catalytic efficiencies for shorter and longer chain acyl-ACP substrates reacting with an octanoyl-homoserine lactone synthase Burkholderia mallei BmaI1. With the exception of two-carbon shorter hexanoyl-ACP, the catalytic efficiencies of butyryl-ACP, decanoyl-ACP, and octanoyl-CoA reacting with BmaI1 decreased by greater than 20-fold compared to the native octanoyl-ACP substrate. Furthermore, we also noticed kinetic cooperativity when BmaI1 reacted with non-native acyl-donor substrates. Our kinetic data suggest that non-native acyl-ACP substrates are unable to form a stable and productive BmaI1·acyl-ACP·SAM ternary complex and are thus effectively discriminated by the enzyme. These results offer insights into the molecular basis of substrate recognition for the BmaI1 enzyme. PMID:25215658

  3. Stacking of a stearoyl-ACP thioesterase with a dual-silenced palmitoyl-ACP thioesterase and ∆12 fatty acid desaturase in transgenic soybean.

    PubMed

    Park, Hyunwoo; Graef, George; Xu, Yixiang; Tenopir, Patrick; Clemente, Tom E

    2014-10-01

    Soybean (Glycine max (L.) Merr) is valued for both its protein and oil, whose seed is composed of 40% and 20% of each component, respectively. Given its high percentage of polyunsaturated fatty acids, linoleic acid and linolenic acid, soybean oil oxidative stability is relatively poor. Historically food processors have employed a partial hydrogenation process to soybean oil as a means to improve both the oxidative stability and functionality in end-use applications. However, the hydrogenation process leads to the formation of trans-fats, which are associated with negative cardiovascular health. As a means to circumvent the need for the hydrogenation process, genetic approaches are being pursued to improve oil quality in oilseeds. In this regard, we report here on the introduction of the mangosteen (Garcinia mangostana) stearoyl-ACP thioesterase into soybean and the subsequent stacking with an event that is dual-silenced in palmitoyl-ACP thioesterase and ∆12 fatty acid desaturase expression in a seed-specific fashion. Phenotypic analyses on transgenic soybean expressing the mangosteen stearoyl-ACP thioesterase revealed increases in seed stearic acid levels up to 17%. The subsequent stacked with a soybean event silenced in both palmitoyl-ACP thioesterase and ∆12 fatty acid desaturase activity, resulted in a seed lipid phenotype of approximately 11%-19% stearate and approximately 70% oleate. The oil profile created by the stack was maintained for four generations under greenhouse conditions and a fifth generation under a field environment. However, in generation six and seven under field conditions, the oleate levels decreased to 30%-40%, while the stearic level remained elevated. PMID:24909647

  4. USGS tethered ACP platforms: New design means more safety and accuracy

    USGS Publications Warehouse

    Morlock, S.E.; Stewart, J.A.; Rehmel, M.S.

    2004-01-01

    The US Geological Survey has developed an innovative tethered platform that supports an Acoustic Current Profiler (ACP) in making stream-flow measurements (use of the term ACP in this article refers to a class of instruments and not a specific brand name or model). The tethered platform reduces the hazards involved in conventional methods of stream-flow measurement. The use of the platform reduces or eliminates time spent by personnel in streams and boats or on bridges and cableway and stream-flow measurement accuracy is increased.

  5. The LOV Protein of Xanthomonas citri subsp. citri Plays a Significant Role in the Counteraction of Plant Immune Responses during Citrus Canker

    PubMed Central

    Kraiselburd, Ivana; Daurelio, Lucas D.; Tondo, María Laura; Merelo, Paz; Cortadi, Adriana A.; Talón, Manuel; Tadeo, Francisco R.; Orellano, Elena G.

    2013-01-01

    Pathogens interaction with a host plant starts a set of immune responses that result in complex changes in gene expression and plant physiology. Light is an important modulator of plant defense response and recent studies have evidenced the novel influence of this environmental stimulus in the virulence of several bacterial pathogens. Xanthomonas citri subsp. citri is the bacterium responsible for citrus canker disease, which affects most citrus cultivars. The ability of this bacterium to colonize host plants is influenced by bacterial blue-light sensing through a LOV-domain protein and disease symptoms are considerably altered upon deletion of this protein. In this work we aimed to unravel the role of this photoreceptor during the bacterial counteraction of plant immune responses leading to citrus canker development. We performed a transcriptomic analysis in Citrus sinensis leaves inoculated with the wild type X. citri subsp. citri and with a mutant strain lacking the LOV protein by a cDNA microarray and evaluated the differentially regulated genes corresponding to specific biological processes. A down-regulation of photosynthesis-related genes (together with a corresponding decrease in photosynthesis rates) was observed upon bacterial infection, this effect being more pronounced in plants infected with the lov-mutant bacterial strain. Infection with this strain was also accompanied with the up-regulation of several secondary metabolism- and defense response-related genes. Moreover, we found that relevant plant physiological alterations triggered by pathogen attack such as cell wall fortification and tissue disruption were amplified during the lov-mutant strain infection. These results suggest the participation of the LOV-domain protein from X. citri subsp. citri in the bacterial counteraction of host plant defense response, contributing in this way to disease development. PMID:24260514

  6. Comparative genomic and transcriptome analyses of pathotypes of Xanthomonas citri subsp. citri provide insights into mechanisms of bacterial virulence and host range

    PubMed Central

    2013-01-01

    Background Citrus bacterial canker is a disease that has severe economic impact on citrus industries worldwide and is caused by a few species and pathotypes of Xanthomonas. X. citri subsp. citri strain 306 (XccA306) is a type A (Asiatic) strain with a wide host range, whereas its variant X. citri subsp. citri strain Aw12879 (Xcaw12879, Wellington strain) is restricted to Mexican lime. Results To characterize the mechanism for the differences in host range of XccA and Xcaw, the genome of Xcaw12879 that was completed recently was compared with XccA306 genome. Effectors xopAF and avrGf1 are present in Xcaw12879, but were absent in XccA306. AvrGf1 was shown previously for Xcaw to cause hypersensitive response in Duncan grapefruit. Mutation analysis of xopAF indicates that the gene contributes to Xcaw growth in Mexican lime but does not contribute to the limited host range of Xcaw. RNA-Seq analysis was conducted to compare the expression profiles of Xcaw12879 and XccA306 in Nutrient Broth (NB) medium and XVM2 medium, which induces hrp gene expression. Two hundred ninety two and 281 genes showed differential expression in XVM2 compared to in NB for XccA306 and Xcaw12879, respectively. Twenty-five type 3 secretion system genes were up-regulated in XVM2 for both XccA and Xcaw. Among the 4,370 common genes of Xcaw12879 compared to XccA306, 603 genes in NB and 450 genes in XVM2 conditions were differentially regulated. Xcaw12879 showed higher protease activity than XccA306 whereas Xcaw12879 showed lower pectate lyase activity in comparison to XccA306. Conclusions Comparative genomic analysis of XccA306 and Xcaw12879 identified strain specific genes. Our study indicated that AvrGf1 contributes to the host range limitation of Xcaw12879 whereas XopAF contributes to virulence. Transcriptome analyses of XccA306 and Xcaw12879 presented insights into the expression of the two closely related strains of X. citri subsp. citri. Virulence genes including genes encoding T3SS components

  7. Preparation of fatty-acylated derivatives of acyl carrier protein using Vibrio harveyi acyl-ACP synthetase.

    PubMed

    Shen, Z; Fice, D; Byers, D M

    1992-07-01

    A simple two-step purification of Vibrio harveyi fatty acyl-acyl carrier protein (acyl-ACP) synthetase, which is useful for the quantitative preparation and analysis of fatty-acylated derivatives of ACP, is described. Acyl-ACP synthetase can be partially purified from extracts of this bioluminescent bacterium by Cibacron blue chromatography and Sephacryl S-300 gel filtration and is stable for months at -20 degrees C in the presence of glycerol. Incubation of ACP from Escherichia coli with ATP and radiolabeled fatty acids (6 to 16 carbons in length) in the presence of the enzyme resulted in quantitative conversion to biologically active acylated derivatives. The enzyme reaction can be monitored by a filter disk assay to quantitate levels of ACP or by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography to detect ACP in cell extracts. With its broad fatty acid chain length specificity and optimal activity in mild nondenaturing buffers, the soluble V. harveyi acyl-ACP synthetase provides an attractive alternative to current chemical and enzymatic methods of acyl-ACP preparation and analysis. PMID:1514693

  8. Odor coding in a disease-transmitting herbivorous insect, the Asian citrus psyllid.

    PubMed

    Coutinho-Abreu, Iliano V; McInally, Shane; Forster, Lisa; Luck, Robert; Ray, Anandasankar

    2014-07-01

    Olfactory systems discriminate odorants very efficiently and herbivorous insects use them to find hosts in confounding and complex odor landscapes. The Asian citrus psyllid (ACP), Diaphorina citri, feeds on citrus flush and transmits Candidatus Liberibacter that causes citrus greening disease globally. Here, we perform a systematic analysis of odor detection in the ACP antenna using single-unit electrophysiology of rhinarial plate sensilla to a large panel of odorants from plants. We identify neurons that respond strongly to odorants found in the host citrus plants. Comparisons with the generalist yeast-feeding Drosophila melanogaster and specialist anthropophilic Anopheles gambiae reveal differences in odor-coding strategies for the citrus-seeking ACP. These findings provide a foundation for understanding host-odor coding in herbivorous insects. PMID:24904081

  9. What's in a Number? Estimating numbers of viable Candidatus Liberibacter asiaticus cells in citrus and ACP

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Knowledge of CLas viability is critical for answering questions about how the organism is proliferating within citrus and ACP, what is the response to therapeutic treatments, and for understanding disease development. Because CLas cannot be grown in culture, estimating cell viability has not been po...

  10. Introducing an Absolute Cavity Pyrgeometer (ACP) for Improving the Atmospheric Longwave Irradiance Measurement (Poster)

    SciTech Connect

    Reda, I.; Stoffel, T.

    2012-03-01

    Advancing climate change research requires accurate and traceable measurement of the atmospheric longwave irradiance. Current measurement capabilities are limited to an estimated uncertainty of larger than +/- 4 W/m2 using the interim World Infrared Standard Group (WISG). WISG is traceable to the Systeme international d'unites (SI) through blackbody calibrations. An Absolute Cavity Pyrgeometer (ACP) is being developed to measure absolute outdoor longwave irradiance with traceability to SI using the temperature scale (ITS-90) and the sky as the reference source, instead of a blackbody. The ACP was designed by NREL and optically characterized by the National Institute of Standards and Technology (NIST). Under clear-sky and stable conditions, the responsivity of the ACP is determined by lowering the temperature of the cavity and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The absolute atmospheric longwave irradiance is then calculated with an uncertainty of +/- 3.96 W/m2 with traceability to SI. The measured irradiance by the ACP was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the WISG.

  11. Interaction network and mass spectrometry data of Xanthomonas citri subsp. citri surface proteins from differential proteomic analysis of infectious and non-infectious cells.

    PubMed

    Carnielli, Carolina Moretto; Artier, Juliana; Franco de Oliveira, Julio Cezar; Novo-Mansur, Maria Teresa Marques

    2016-09-01

    Here we provide the mass-spectrometry and in silico interaction network dataset of proteins identified on our research article on surface proteomic analysis from Xanthomonas citri subsp. citri (XAC) cells grown in vivo (infectious) and in vitro (non-infectious, control) by 2D-DIGE approach. Fluorescence labeling of proteins were performed on intact cells followed by cellular lysis and labeled spots from 2D gel differing in abundance between the two conditions (ANOVA, p-value<0.05) were analyzed by a nano-electrospray tandem mass spectrometry Q-Tof Ultima API mass spectrometer (MicroMass/Waters) (LC-ESI-MS/MS). This article contains raw data of proteins detected in the 79 spots analyzed by LC-ESI-MS/MS approach and also an enrichment analysis on the resulting protein-protein interaction network performed with the Integrated Interactome System (IIS) platform and Cytoscape software. The data are supplementary to our original research article, "Xanthomonas citri subsp. citri surface proteome by 2D-DIGE: ferric enterobactin receptor and other outer membrane proteins potentially involved in citric host interaction" (Carnielli et al., 2016) [1], and raw data are available via Peptide Atlas (ftp://PASS00850:ZJ7425v@ftp.peptideatlas.org/). PMID:27595129

  12. Transmission of different strains of Spiroplasma citri to carrot and citrus by Circulifer tenellus Baker (Hemiptera:Cicadellidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Carrot purple leaf disease (CPLD) was associated with the presence of Spiroplasma citri in 2006 in the state of Washington, USA (Lee et al. 2006). The objectives of this work were to (1) confirm S. citri as the causal agent of CPLD by fulfilling Koch’s postulates, (2) to determine whether carrot str...

  13. Characterization of the recA gene regions of Spiroplasma citri and Spiroplasma melliferum.

    PubMed Central

    Marais, A; Bove, J M; Renaudin, J

    1996-01-01

    In previous studies (A. Marais, J. M. Bove, and J. Renaudin, J. Bacteriol. 178:862-870, 1996), we have shown that the recA gene of Spiroplasma citri R8A2 was restricted to the first 390 nucleotides of the N-terminal part. PCR amplification and sequencing studies of five additional strains of S. citri have revealed that these strains had the same organization at the recA region as the R8A2 strain. In contrast to S. citri, Spiroplasma melliferum was found to contain a full-length recA gene. However, in all five S. melliferum strains tested, a TAA stop codon was found within the N-terminal region of the recA reading frame. Our results suggest that S. melliferum, as well as S. citri, is RecA deficient. In agreement with the recA mutant genotype of S. citri and S. melliferum, we have shown that these organisms are highly sensitive to UV irradiation. PMID:8955327

  14. Mycolic acid biosynthesis and enzymic characterization of the beta-ketoacyl-ACP synthase A-condensing enzyme from Mycobacterium tuberculosis.

    PubMed

    Kremer, Laurent; Dover, Lynn G; Carrère, Séverine; Nampoothiri, K Madhavan; Lesjean, Sarah; Brown, Alistair K; Brennan, Patrick J; Minnikin, David E; Locht, Camille; Besra, Gurdyal S

    2002-06-01

    Mycolic acids consist of long-chain alpha-alkyl-beta-hydroxy fatty acids that are produced by successive rounds of elongation catalysed by a type II fatty acid synthase (FAS-II). A key feature in the elongation process is the condensation of a two-carbon unit from malonyl-acyl-carrier protein (ACP) to a growing acyl-ACP chain catalysed by a beta-ketoacyl-ACP synthase (Kas). In the present study, we provide evidence that kasA from Mycobacterium tuberculosis encodes an enzyme that elongates in vivo the meromycolate chain, in both Mycobacterium smegmatis and Mycobacterium chelonae. We demonstrate that KasA belongs to the FAS-II system, which utilizes primarily palmitoyl-ACP rather than short-chain acyl-ACP primers. Furthermore, in an in vitro condensing assay using purified recombinant KasA, palmitoyl-AcpM and malonyl-AcpM, KasA was found to express Kas activity. Also, mutated KasA proteins, with mutation of Cys(171), His(311), Lys(340) and His(345) to Ala abrogated the condensation activity of KasA in vitro completely. Finally, purified KasA was highly sensitive to cerulenin, a well-known inhibitor of Kas, which may lead to the development of novel anti-mycobacterial drugs targeting KasA. PMID:12023885

  15. Solution Structure of 4'-Phosphopantetheine - GmACP3 from Geobacter Metallireducens: A Specialized Acyl Carrier Protein with Atypical Structural Features and a Putative Role in Lipopolysaccharide Biosyntheses

    SciTech Connect

    Ramelot, Theresa A.; Smola, Matthew J.; Lee, Hsiau-Wei; Ciccosanti, Colleen; Hamilton, Keith; Acton, Thomas; Xiao, Rong; Everett, John K.; Prestegard, James H.; Montelione, Gaetano; Kennedy, Michael A.

    2011-03-08

    GmACP3 from Geobacter metallireducens is a specialized acyl carrier protein (ACP) whose gene, gmet_2339, is located near genes encoding many proteins involved in lipopolysaccharide (LPS) biosynthesis, indicating a likely function for GmACP3 in LPS production. By overexpression in Escherichia coli, about 50% holo-GmACP3 and 50% apo-GmACP3 were obtained. Apo-GmACP3 exhibited slow precipitation and non-monomeric behavior by 15NNMRrelaxation measurements. Addition of 4'-phosphopantetheine (4'-PP) via enzymatic conversion by E. coli holo-ACP synthase resulted in stable >95% holo-GmACP3 that was characterized as monomeric by 15N relaxation measurements and had no indication of conformational exchange. We have determined a high-resolution solution structure of holo-GmACP3 by standard NMR methods, including refinement with two sets of NH residual dipolar couplings, allowing for a detailed structural analysis of the interactions between 4'-PP and GmACP3. Whereas the overall four helix bundle topology is similar to previously solved ACP structures, this structure has unique characteristics, including an ordered 4'-PP conformation that places the thiol at the entrance to a central hydrophobic cavity near a conserved hydrogen-bonded Trp-His pair. These residues are part of a conservedWDSLxH/N motif found in GmACP3 and its orthologs. The helix locations and the large hydrophobic cavity are more similar tomediumand long-chain acyl-ACPs than to other apo- and holo-ACP structures. Taken together, structural characterization along with bioinformatic analysis of nearby genes suggests that GmACP3 is involved in lipid A acylation, possibly by atypical long-chain hydroxy fatty acids, and potentially is involved in synthesis of secondary metabolites.

  16. Results of First Outdoor Comparison Between Absolute Cavity Pyrgeometer (ACP) and Infrared Integrating Sphere (IRIS) Radiometer at PMOD (Presentation)

    SciTech Connect

    Reda, I.; Grobner, J.; Wacker, S.; Stoffel, T.

    2013-03-01

    The ACP and IRIS are developed to establish a world reference for calibrating pyrgeometers with traceability to SI units. The two radiometers are unwindowed with negligible spectral dependence, and traceable to SI units through the temperature scale (ITS-90). The first outdoor comparison between the two designs was held from January 28 to February 8, 2013 at the Physikalisch-Metorologisches Observatorium Davos (PMOD). The difference between the irradiance measured by ACP and that of IRIS was within 1 W/m2. A difference of 5 W/m2 was observed between the irradiance measured by ACP&IRIS and that of the interim World Infrared Standard Group (WISG).

  17. Effects of the addition of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on mechanical properties of luting and lining glass ionomer cement

    NASA Astrophysics Data System (ADS)

    Heravi, Farzin; Bagheri, Hossein; Rangrazi, Abdolrasoul; Mojtaba Zebarjad, Seyed

    2016-07-01

    Recently, the addition of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) into glass ionomer cements (GICs) has attracted interest due to its remineralization of teeth and its antibacterial effects. However, it should be investigated to ensure that the incorporation of CPP-ACP does not have significant adverse effects on its mechanical properties. The purpose of this study was to evaluate the effects of the addition of CPP-ACP on the mechanical properties of luting and lining GIC. The first step was to synthesize the CPP-ACP. Then the CPP-ACP at concentrations of 1%, 1.56% and 2% of CPP-ACP was added into a luting and lining GIC. GIC without CPP-ACP was used as a control group. The results revealed that the incorporation of CPP-ACP up to 1.56%(w/w) increased the flexural strength (29%), diametral tensile strength (36%) and microhardness (18%), followed by a reduction in these mechanical properties at 2%(w/w) CPP-ACP. The wear rate was significantly decreased (23%) in 1.56%(w/w) concentration of CPP-ACP and it was increased in 2%(w/w). Accordingly, the addition of 1.56%(w/w) CPP-ACP into luting and lining GIC had no adverse effect on the mechanical properties of luting and lining GIC and could be used in clinical practice.

  18. Inhibition of a Mycobacterium tuberculosis beta-ketoacyl ACP synthase by isoniazid.

    PubMed

    Mdluli, K; Slayden, R A; Zhu, Y; Ramaswamy, S; Pan, X; Mead, D; Crane, D D; Musser, J M; Barry, C E

    1998-06-01

    Although isoniazid (isonicotinic acid hydrazide, INH) is widely used for the treatment of tuberculosis, its molecular target has remained elusive. In response to INH treatment, saturated hexacosanoic acid (C26:0) accumulated on a 12-kilodalton acyl carrier protein (AcpM) that normally carried mycolic acid precursors as long as C50. A protein species purified from INH-treated Mycobacterium tuberculosis was shown to consist of a covalent complex of INH, AcpM, and a beta-ketoacyl acyl carrier protein synthase, KasA. Amino acid-altering mutations in the KasA protein were identified in INH-resistant patient isolates that lacked other mutations associated with resistance to this drug. PMID:9616124

  19. Transition metal HE`s - VII ACP. Progress report, August 1971--October 1971

    SciTech Connect

    Clink, G.L.

    1998-12-31

    Physical and physicochemical properties of hexaamminechromium III perchlorate (ACP) were investigated to determine its potentiality for HE and/or HE component application. Physicochemical properties obtained through investigation of isothermally aged ACP under conditions of various system and boundary restrictions (open and closed; 50 and 80 C; 0.65 and 0.85 g/cc) show the material to be substantially stable under these simulated isothermal storage conditions from a standpoint of infrared and DTA thermal pattern behavior and chemical analysis of aged residues. Spark sensitivity was 0.25 joules at 5 kv (by LASL type test) and impact sensitivity was about 23 and 14 cm on sandpaper (12A) and steel (12B), respectively.

  20. Effect of CPP-ACP Paste on Dental Caries in Primary Teeth

    PubMed Central

    Sitthisettapong, T.; Phantumvanit, P.; Huebner, C.; DeRouen, T.

    2012-01-01

    This clinical trial tested the effect of daily application of 10% w/v calcium phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste for 1 yr when added to regular toothbrushing with fluoridated toothpaste to prevent dental caries in pre-school children. High-caries-risk children aged 2½ to 3½ yrs in a suburban area of central Thailand were assigned to receive either CPP-ACP (n = 150) or a placebo control (n = 146) in addition to fluoridated toothpaste. The International Caries Detection and Assessment System (ICDAS) was recorded at baseline, 6 mos, and 1 yr. At 1 yr, a significant increase in mean numbers of enamel and dentin caries lesions, as well as dmfs, was found in both groups (p < 0.001). No significant difference was observed between groups on these 3 outcome measures (p = 0.23, 0.84, and 0.91, respectively). The odds of enamel caries lesion transitions to a state of regression or stability, compared with progression from baseline, was also not different between groups [OR = 1.00, 95% CI (0.86, 1.17)]. This trial found that daily application of 10% w/v CPP-ACP paste on school days for 1 yr, when added to regular toothbrushing with a fluoride toothpaste, had no significant added effect in preventing caries in the primary dentition of these pre-school children (ClinicalTrials.gov number CT01 604109). PMID:22805294

  1. Effect of CPP-ACP paste on dental caries in primary teeth: a randomized trial.

    PubMed

    Sitthisettapong, T; Phantumvanit, P; Huebner, C; Derouen, T

    2012-09-01

    This clinical trial tested the effect of daily application of 10% w/v calcium phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste for 1 yr when added to regular toothbrushing with fluoridated toothpaste to prevent dental caries in pre-school children. High-caries-risk children aged 2½ to 3½ yrs in a suburban area of central Thailand were assigned to receive either CPP-ACP (n = 150) or a placebo control (n = 146) in addition to fluoridated toothpaste. The International Caries Detection and Assessment System (ICDAS) was recorded at baseline, 6 mos, and 1 yr. At 1 yr, a significant increase in mean numbers of enamel and dentin caries lesions, as well as dmfs, was found in both groups (p < 0.001). No significant difference was observed between groups on these 3 outcome measures (p = 0.23, 0.84, and 0.91, respectively). The odds of enamel caries lesion transitions to a state of regression or stability, compared with progression from baseline, was also not different between groups [OR = 1.00, 95% CI (0.86, 1.17)]. This trial found that daily application of 10% w/v CPP-ACP paste on school days for 1 yr, when added to regular toothbrushing with a fluoride toothpaste, had no significant added effect in preventing caries in the primary dentition of these pre-school children (ClinicalTrials.gov number CT01 604109). PMID:22805294

  2. Histochemical localization and characterization of AKP, ACP, NSE, and POD from cultured Apostichopus japonicus

    NASA Astrophysics Data System (ADS)

    Li, Jiye; Sun, Xiuqin; Zheng, Fengrong; Sun, Hushan

    2009-09-01

    We investigated the distribution of four enzymes involved in the immune response of Apostichopus japonicus. We collected samples of the tentacles, papillate podium, integument, respiratory tree, and digestive tract and stained them for acid phosphatase (ACP), alkaline phosphatase (AKP), non-specific esterase (NSE) and peroxidase (POD) activity. The distribution and content of ACP, AKP, NSE, and POD differed among the tissues. The coelomic epithelium of the tentacle, papillate podium, and integument and the mucous layer of respiratory tree were positive for ACP activity. The coelomic epithelium and cuticular layer of the tentacle, papillate podium, and integument and the mucous layer and tunica externa of the respiratory tree and digestive tract stained positive or weakly positive for AKP activity. Almost all the epithelial tissues stained positive, strongly positive, or very strongly positive for NSE activity. The cuticular layer of the tentacle and integument and the mucous layer, tunica submucosa, and tunica externa of the respiratory tree and digestive tract stained positive for POD activity. We hypothesize that these enzymes play a role in the immune response in A. japonicus.

  3. Acyl-ACP thioesterases from macadamia (Macadamia tetraphylla) nuts: cloning, characterization and their impact on oil composition.

    PubMed

    Moreno-Pérez, Antonio J; Sánchez-García, Alicia; Salas, Joaquín J; Garcés, Rafael; Martínez-Force, Enrique

    2011-01-01

    The mechanisms by which macadamia nuts accumulate the unusual palmitoleic and asclepic acyl moieties, which constitute up to 20% of the fatty acids in some varieties, are still unknown. Acyl-acyl carrier protein (ACP) thioesterases (EC 3.1.2.14) are intraplastidial enzymes that terminate the synthesis of fatty acids in plants and that facilitate the export of the acyl moieties to the endoplasmic reticulum where they can be used in the production of glycerolipids. Here, we have investigated the possible role of acyl-ACP thioesterase activity in the composition of macadamia kernel oil. Accordingly, two acyl-ACP thioesterases were cloned from developing macadamia kernels, one of the FatA type and the other of the FatB type. These enzymes were heterologously expressed in Escherichia coli, and the recombinant thioesterases were purified, characterized kinetically and assayed with a variety of substrates, demonstrating the high specificity of macadamia FatA towards 16:1-ACP. Acyl-ACP thioesterase activity was also characterized in crude extracts from two different varieties of macadamia, Cate and Beaumont, which accumulate different amounts of n-7 fatty acids. The impact of acyl-ACP thioesterase activities on the oil composition of these kernels is discussed in the light of these results. PMID:21071236

  4. Mode of action of metabolites from Bacillus sp. strain IBA 33 on Geotrichum citri-aurantii arthroconidia.

    PubMed

    Gordillo, María Antonieta; Navarro, Antonio R; Maldonado, María Cristina

    2015-11-01

    Geotrichum citri-aurantii is a postharvest phytopathogenic fungus of lemons. We studied the mode of action of antifungal metabolites from Bacillus sp. strain IBA 33 on arthroconidia of G. citri-aurantii. These metabolites are lipopeptides belonging to the iturin family. Membrane permeabilization of G. citri-aurantii was analyzed and mitochondrial respiratory rate was evaluated. Disturbance of the plasma membrane promotes the leakage of many cellular components into the surrounding media, and mitochondrial membrane disorganization promotes the inhibition of the respiratory rate. Our findings provide insights into the ability of lipopeptides to suppress plant fungal pathogens and their possible agronomical applications. PMID:26394707

  5. The Amino Acid Arginine 210 of the Response Regulator HrpG of Xanthomonas citri subsp. citri Is Required for HrpG Function in Virulence.

    PubMed

    Ficarra, Florencia A; Garofalo, Cecilia G; Gottig, Natalia; Ottado, Jorgelina

    2015-01-01

    Xanthomonas citri subsp. citri colonizes its hosts through the trafficking of effector proteins to the plant cell by the type III protein secretion system. In X. citri subsp. citri, as in other plant pathogens, the hrp cluster encodes the type III protein secretion system and is regulated by the transcription factors HrpG and HrpX. HrpG belongs to the OmpR family's response regulator of EnvZ/OmpR two-component signal transduction system. Here, we show that the arginine 210 residue is crucial for the transcriptional activity of HrpG revealed by the absence of disease in host plants and hypersensitive response in non-host plants when a strain carrying this point mutation is used in plant infiltration assays. Also, this strain showed decreased expression levels of hrp genes in bacteria grown in culture or when they were recovered from citrus leaves. Moreover, we show for the first time that HrpG binds to both hrpX and its own promoter, and the change of the arginine 210 by a cysteine does not prevent the binding to both promoters. Nevertheless, in vitro hrpX transcription was observed only with HrpG whereas no transcription was detected with the R210C mutant. HrpG was able to interact with itself as well as with the mutant R210C suggesting that it functions as a dimer. The mutant protein R210C showed altered protease sensitivity, suggesting that Arg210 is essential for protein active conformation and thus for transcriptional activity. Our results indicate that arginine 210 in HrpG, as it may occur with this conserved residue in other members of this family of response regulators, is not required for DNA binding whereas is essential for hrp genes transcription and therefore for pathogenicity and HR induction. PMID:25961560

  6. The Amino Acid Arginine 210 of the Response Regulator HrpG of Xanthomonas citri subsp. citri Is Required for HrpG Function in Virulence

    PubMed Central

    Gottig, Natalia; Ottado, Jorgelina

    2015-01-01

    Xanthomonas citri subsp. citri colonizes its hosts through the trafficking of effector proteins to the plant cell by the type III protein secretion system. In X. citri subsp. citri, as in other plant pathogens, the hrp cluster encodes the type III protein secretion system and is regulated by the transcription factors HrpG and HrpX. HrpG belongs to the OmpR family’s response regulator of EnvZ/OmpR two-component signal transduction system. Here, we show that the arginine 210 residue is crucial for the transcriptional activity of HrpG revealed by the absence of disease in host plants and hypersensitive response in non-host plants when a strain carrying this point mutation is used in plant infiltration assays. Also, this strain showed decreased expression levels of hrp genes in bacteria grown in culture or when they were recovered from citrus leaves. Moreover, we show for the first time that HrpG binds to both hrpX and its own promoter, and the change of the arginine 210 by a cysteine does not prevent the binding to both promoters. Nevertheless, in vitro hrpX transcription was observed only with HrpG whereas no transcription was detected with the R210C mutant. HrpG was able to interact with itself as well as with the mutant R210C suggesting that it functions as a dimer. The mutant protein R210C showed altered protease sensitivity, suggesting that Arg210 is essential for protein active conformation and thus for transcriptional activity. Our results indicate that arginine 210 in HrpG, as it may occur with this conserved residue in other members of this family of response regulators, is not required for DNA binding whereas is essential for hrp genes transcription and therefore for pathogenicity and HR induction. PMID:25961560

  7. Reduced susceptibility to Xanthomonas citri in transgenic citrus expressing the FLS2 receptor from Nicotiana benthamiana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Overexpression of plant pattern-recognition receptors (PRRs) by genetic engineering provides a novel approach to enhance plant immunity and broad-spectrum disease resistance. The citrus canker disease associated with Xanthomonas citri is one of the important diseases damaging citrus production world...

  8. Genetic Diversity of Spiroplasma citri strains from Different Regions, Hosts, and Isolation Dates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spiroplasma citri, a phloem-limited, leafhopper-transmitted pathogen, causes citrus stubborn disease (CSD). Losses due to CSD in California orchards has grown over the past decade. To investigate the possibility of introduction or emergence of a new spiroplasma strain, a study of genetic diversity ...

  9. Isolation and characterization of Aschersonia placenta from citrus orchards and its pathogenicity towards Dialeurodes citri (Ashmead).

    PubMed

    Wang, Pingping; Song, Xuhong; Zhang, Hongyu

    2013-02-01

    For selecting potential biological agents to control Dialeurodes citri, a major insect pest in China's citrus orchards, 75 native Aschersonia isolates were selected from infected whiteflies in citrus orchards and were evaluated for virulence to third instar nymphs of D. citri at a concentration of 1 × 10(6)conidia/ml. The mortality rates of D. citri varied from 0% to 72.70%. Among the 75 Aschersonia isolates, three (HB10, HB12 and ZJ9) were the most virulent and pathogenic to D. citri and caused more than 69% mortality. The 50% lethal concentration (LC(50)) values of them were 1.86 × 10(6), 3.40 × 10(6) and 6.81 × 10(6)conidia/ml, respectively. The three isolates also produced conidia abundantly on potato dextrose agar medium (3.95 × 10(6), 6.19 × 10(6) and 7.34 × 10(6)conidia/cm(2), respectively). They were identified to be Aschersonia placenta based on their morphological analysis. Phylogenetic analysis showed that these three highly virulent Aschersonia isolates belong to a strongly supported clade that includes two other A. placenta isolates obtained from Vietnam and Thailand. In summary, these results indicate the possibility of developing the three most virulent A. placenta isolates as microbiological control agents against citrus whitefly. PMID:23160084

  10. Molecular Detection of Spiroplasma Citri Associated with Stubborn Disease in Citrus Orchards in Syria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spiroplasma citri, a phloem-limited pathogen, causes citrus stubborn disease (CSD) and can be transmitted from plant to plant by several species of phloem-feeding leafhoppers. CSD is an important disorder in certain warm and arid citrus-growing areas, and its agent has been recorded from several Med...

  11. Influence of temperature and humidity on survival of Penicillium digitatum and Geotrichum citri-aurantii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Longevity of conidia of Penicillium digitatum and arthrospores of Geotrichum citri-aurantii, cause of green mold and sour rot of citrus, respectively, was determined. Conidia of P. digitatum were exposed to ambient summer conditions in central California or to conditions of controlled temperature an...

  12. Reduced Susceptibility to Xanthomonas citri in Transgenic Citrus Expressing the FLS2 Receptor From Nicotiana benthamiana.

    PubMed

    Hao, Guixia; Pitino, Marco; Duan, Yongping; Stover, Ed

    2016-02-01

    Overexpression of plant pattern-recognition receptors by genetic engineering provides a novel approach to enhance plant immunity and broad-spectrum disease resistance. Citrus canker disease associated with Xanthomonas citri is one of the most important diseases damaging citrus production worldwide. In this study, we cloned the FLS2 gene from Nicotiana benthamiana cDNA and inserted it into the binary vector pBinPlus/ARS to transform Hamlin sweet orange and Carrizo citrange. Transgene presence was confirmed by polymerase chain reaction (PCR) and gene expression of NbFLS2 was compared by reverse transcription quantitative PCR. Reactive oxygen species (ROS) production in response to flg22Xcc was detected in transgenic Hamlin but not in nontransformed controls. Low or no ROS production was detected from nontransformed Hamlin seedlings challenged with flg22Xcc. Transgenic plants highly expressing NbFLS2 were selected and were evaluated for resistance to canker incited by X. citri 3213. Our results showed that the integration and expression of the NbFLS2 gene in citrus can increase canker resistance and defense-associated gene expression when challenged with X. citri. These results suggest that canker-susceptible Citrus genotypes lack strong basal defense induced by X. citri flagellin and the resistance of these genotypes can be enhanced by transgenic expression of the flagellin receptor from a resistant species. PMID:26554734

  13. DISEASE DEVELOPMENT AND SYMPTOM EXPRESSION OF XANTHOMONAS AXONOPODIS PV. CITRI IN VARIOUS CITRUS PLANT TISSUES.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experimental inoculations of Xanthomonas axonopodis pv. citri (Xac) in different tissues of Tahiti lime and Pineapple sweet orange were conducted monthly under natural conditions in Réunion Island. The interactions between a set of environmental and epidemic variables associated with disease express...

  14. Citrus stubborn symptom severity and Spiroplasma citri location within the tress canopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The severity of symptoms of citrus stubborn disease (CSD) within an orchard can range from mild to severe, but whether factors other than pathogen titer or duration of infection impact severity is not known. We tested the hypothesis that the canopy distribution of the pathogen, Spiroplasma citri, i...

  15. Identification of Genes Required for Secretion of the Francisella Oxidative Burst-Inhibiting Acid Phosphatase AcpA.

    PubMed

    Hoang, Ky Van; Chen, Carolyn G; Koopman, Jacob; Moshiri, Jasmine; Adcox, Haley E; Gunn, John S

    2016-01-01

    Francisella tularensis is a Tier 1 bioterror threat and the intracellular pathogen responsible for tularemia in humans and animals. Upon entry into the host, Francisella uses multiple mechanisms to evade killing. Our previous studies have shown that after entering its primary cellular host, the macrophage, Francisella immediately suppresses the oxidative burst by secreting a series of acid phosphatases including AcpA-B-C and HapA, thereby evading the innate immune response of the macrophage and enhancing survival and further infection. However, the mechanism of acid phosphatase secretion by Francisella is still unknown. In this study, we screened for genes required for AcpA secretion in Francisella. We initially demonstrated that the known secretion systems, the putative Francisella-pathogenicity island (FPI)-encoded Type VI secretion system and the Type IV pili, do not secrete AcpA. Using random transposon mutagenesis in conjunction with ELISA, Western blotting and acid phosphatase enzymatic assays, a transposon library of 5450 mutants was screened for strains with a minimum 1.5-fold decrease in secreted (culture supernatant) AcpA, but no defect in cytosolic AcpA. Three mutants with decreased supernatant AcpA were identified. The transposon insertion sites of these mutants were revealed by direct genomic sequencing or inverse-PCR and sequencing. One of these mutants has a severe defect in AcpA secretion (at least 85% decrease) and is a predicted hypothetical inner membrane protein. Interestingly, this mutant also affected the secretion of the FPI-encoded protein, VgrG. Thus, this screen identified novel protein secretion factors involved in the subversion of host defenses. PMID:27199935

  16. Identification of Genes Required for Secretion of the Francisella Oxidative Burst-Inhibiting Acid Phosphatase AcpA

    PubMed Central

    Hoang, Ky Van; Chen, Carolyn G.; Koopman, Jacob; Moshiri, Jasmine; Adcox, Haley E.; Gunn, John S.

    2016-01-01

    Francisella tularensis is a Tier 1 bioterror threat and the intracellular pathogen responsible for tularemia in humans and animals. Upon entry into the host, Francisella uses multiple mechanisms to evade killing. Our previous studies have shown that after entering its primary cellular host, the macrophage, Francisella immediately suppresses the oxidative burst by secreting a series of acid phosphatases including AcpA-B-C and HapA, thereby evading the innate immune response of the macrophage and enhancing survival and further infection. However, the mechanism of acid phosphatase secretion by Francisella is still unknown. In this study, we screened for genes required for AcpA secretion in Francisella. We initially demonstrated that the known secretion systems, the putative Francisella-pathogenicity island (FPI)-encoded Type VI secretion system and the Type IV pili, do not secrete AcpA. Using random transposon mutagenesis in conjunction with ELISA, Western blotting and acid phosphatase enzymatic assays, a transposon library of 5450 mutants was screened for strains with a minimum 1.5-fold decrease in secreted (culture supernatant) AcpA, but no defect in cytosolic AcpA. Three mutants with decreased supernatant AcpA were identified. The transposon insertion sites of these mutants were revealed by direct genomic sequencing or inverse-PCR and sequencing. One of these mutants has a severe defect in AcpA secretion (at least 85% decrease) and is a predicted hypothetical inner membrane protein. Interestingly, this mutant also affected the secretion of the FPI-encoded protein, VgrG. Thus, this screen identified novel protein secretion factors involved in the subversion of host defenses. PMID:27199935

  17. Isolation of Vibrio harveyi acyl carrier protein and the fabG, acpP, and fabF genes involved in fatty acid biosynthesis.

    PubMed Central

    Shen, Z; Byers, D M

    1996-01-01

    We report the isolation of Vibrio harveyi acyl carrier protein (ACP) and cloning of a 3,973-bp region containing the fabG (encoding 3-ketoacyl-ACP reductase, 25.5 kDa), acpP (encoding ACP, 8.7 kDa), fabF (encoding 3-ketoacyl-ACP synthase II, 43.1 kDa), and pabC (encoding aminodeoxychorismate lyase, 29.9 kDa) genes. Predicted amino acid sequences were, respectively, 78, 86, 76, and 35% identical to those of the corresponding Escherichia coli proteins. Five of the 11 sequence differences between V. harveyi and E. coli ACP were nonconservative amino acid differences concentrated in a loop region between helices I and II. PMID:8550484

  18. Development of the ACP safeguards neutron counter for PWR spent fuel rods

    NASA Astrophysics Data System (ADS)

    Lee, Tae-Hoon; Menlove, Howard O.; Lee, Sang-Yoon; Kim, Ho-Dong

    2008-04-01

    An advanced neutron multiplicity counter has been developed for measuring spent fuel in the Advanced spent fuel Conditioning Process (ACP) at the Korea Atomic Energy Research Institute (KAERI). The counter uses passive neutron multiplicity counting to measure the 244Cm content in spent fuel. The input to the ACP process is spent fuel from pressurized water reactors (PWRs), and the high intensity of the gamma-ray exposure from spent fuel requires a careful design of the counter to measure the neutrons without gamma-ray interference. The nuclear safeguards for the ACP facility requires the measurement of the spent fuel input to the process and the Cm/Pu ratio for the plutonium mass accounting. This paper describes the first neutron counter that has been used to measure the neutron multiplicity distribution from spent fuel rods. Using multiple samples of PWR spent fuel rod-cuts, the singles (S), doubles (D), and triples (T) rates of the neutron distribution for the 244Cm nuclide were measured and calibration curves were produced. MCNPX code simulations were also performed to obtain the three counting rates and to compare them with the measurement results. The neutron source term was evaluated by using the ORIGEN-ARP code. The results showed systematic difference of 21-24% in the calibration graphs between the measured and simulation results. A possible source of the difference is that the burnup codes have a 244Cm uncertainty greater than ±15% and it would be systematic for all of the calibration samples. The S/D and D/T ratios are almost constant with an increment of the 244Cm mass, and this indicates that the bias is in the 244Cm neutron source calculation using the ORIGEN-ARP source code. The graphs of S/D and D/T ratios show excellent agreement between measurement and MCNPX simulation results.

  19. Combining CPP-ACP with fluoride: a synergistic remineralization potential of artificially demineralized enamel or not?

    NASA Astrophysics Data System (ADS)

    El-Sayad, I. I.; Sakr, A. K.; Badr, Y. A.

    2008-08-01

    Background and objective: Minimal intervention dentistry (MID) calls for early detection and remineralization of initial demineralization. Laser fluorescence is efficient in detecting changes in mineral tooth content. Recaldent is a product of casein phosphopeptide-amorphous calcium phosphate (CPP- ACP) which delivers calcium and phosphate ions to enamel. A new product which also contains fluoride is launched in United States. The remineralizing potential of CPP- ACP per se, or when combined with 0.22% Fl supplied in an oral care gel on artificially demineralised enamel using laser fluorescence was investigated. Methods: Fifteen sound human molars were selected. Mesial surfaces were tested using He-Cd laser beam at 441.5nm with 18mW power as excitation source on a suitable set-up based on Spex 750 M monochromator provided with PMT for detection of collected auto-fluorescence from sound enamel. Mesial surfaces were subjected to demineralization for ten days. The spectra from demineralized enamel were measured. Teeth were then divided according to the remineralizing regimen into three groups: group I recaldent per se, group II recaldent combined with fluoride gel and group III artificial saliva as a positive control. After following these protocols for three weeks, the spectra from remineralized enamel from the three groups were measured. The spectra of enamel auto-fluorescence were recorded and normalized to peak intensity at about 540 nm to compare between spectra from sound, demineralized and remineralized enamel surfaces. Results: A slight red shift was noticed in spectra from demineralized enamel, while a blue shift may occur in remineralized enamel. Group II showed the highest remineralizing potential. Conclusions: Combining fluoride with CPP-ACP had a synergistic effect on enamel remineralization. In addition, laser auto-fluorescence is an accurate technique for assessment of changes in tooth enamel minerals.

  20. Thiolactomycin-Based Inhibitors of Bacterial β-Ketoacyl-ACP Synthases with in Vivo Activity.

    PubMed

    Bommineni, Gopal R; Kapilashrami, Kanishk; Cummings, Jason E; Lu, Yang; Knudson, Susan E; Gu, Chendi; Walker, Stephen G; Slayden, Richard A; Tonge, Peter J

    2016-06-01

    β-Ketoacyl-ACP synthases (KAS) are key enzymes involved in the type II bacterial fatty acid biosynthesis (FASII) pathway and are putative targets for antibacterial discovery. Several natural product KAS inhibitors have previously been reported, including thiolactomycin (TLM), which is produced by Nocardia spp. Here we describe the synthesis and characterization of optically pure 5R-thiolactomycin (TLM) analogues that show improved whole cell activity against bacterial strains including methicillin-resistant Staphylococcus aureus (MRSA) and priority pathogens such as Francisella tularensis and Burkholderia pseudomallei. In addition, we identify TLM analogues with in vivo efficacy against MRSA and Klebsiella pneumoniae in animal models of infection. PMID:27187871

  1. Short-term storage of canine preantral ovarian follicles using a powdered coconut water (ACP)-based medium.

    PubMed

    Lima, G L; Costa, L L M; Cavalcanti, D M L P; Rodrigues, C M F; Freire, F A M; Fontenele-Neto, J D; Silva, A R

    2010-07-01

    The objective was to investigate the use of powdered coconut water (ACP)-based medium for short-term preservation of canine preantral follicles. Pairs of ovaries from mongrel bitches (n=9) were divided into fragments. One ovarian fragment, treated as a fresh control, was immediately fixed for histological analysis, whereas the other six ovarian fragments were stored either in phosphate-buffered saline (PBS; control group) or ACP medium in isothermal Styrofoam boxes containing biological ice packs. The boxes were sealed and opened only after 12, 24, or 36h. After opening each box, the ovarian fragments were submitted to histological analysis. In total, 12,302 preantral follicles were evaluated, with 64.5% primordial, 33.3% primary, and 2.3% secondary follicles. There were multiple oocytes in 1.3% of the follicles analyzed. At 24h, ACP was more efficient in preserving follicular morphology than PBS (P<0.05). Compared with the fresh control group, a significant reduction in the percentage of morphologically normal ovarian follicles was observed for PBS, starting at 24h; however, the decline started only at 36h for the ACP medium. During the experiment, the temperature inside the isothermal boxes increased from 3 to 9 degrees C (P<0.05), despite a constant room temperature. In conclusion, powdered coconut water (ACP) was an appropriate medium for short-term storage of canine preantral ovarian follicles. PMID:20207405

  2. Acyl-ACP thioesterases from Camelina sativa: cloning, enzymatic characterization and implication in seed oil fatty acid composition.

    PubMed

    Rodríguez-Rodríguez, Manuel Fernando; Salas, Joaquín J; Garcés, Rafael; Martínez-Force, Enrique

    2014-11-01

    Acyl-acyl carrier protein (ACP) thioesterases are intraplastidial enzymes that terminate de novo fatty acid biosynthesis in the plastids of higher plants by hydrolyzing the thioester bond between ACP and the fatty acid synthesized. Free fatty acids are then esterified with coenzyme A prior to being incorporated into the glycerolipids synthesized through the eukaryotic pathway. Acyl-ACP thioesterases belong to the TE14 family of thioester-active enzymes and can be classified as FatAs and FatBs, which differ in their amino acid sequence and substrate specificity. Here, the FatA and FatB thioesterases from Camelina sativa seeds, a crop of interest in plant biotechnology, were cloned, sequenced and characterized. The mature proteins encoded by these genes were characterized biochemically after they were heterologously expressed in Escherichia coli and purified. C. sativa contained three different alleles of both the FatA and FatB genes. These genes were expressed most strongly in expanding tissues in which lipids are very actively synthesized, such as developing seed endosperm. The CsFatA enzyme displayed high catalytic efficiency on oleoyl-ACP and CsFatB acted efficiently on palmitoyl-ACP. The contribution of these two enzymes to the synthesis of C. sativa oil was discussed in the light of these results. PMID:25212866

  3. Imidacloprid sorption kinetics, equilibria, and degradation in sandy soils of Florida.

    PubMed

    Leiva, Jorge A; Nkedi-Kizza, Peter; Morgan, Kelly T; Qureshi, Jawwad A

    2015-05-27

    Imidacloprid (IMD) is a neonicotinoid insecticide soil-drenched on sandy soils of southwest Florida for the control of Diaphorina citri Kuwayama or Asian citrus psyllid (ACP). The ACP vectors causal pathogens of a devastating citrus disease called citrus greening. Understanding the behavior of IMD in these soils and plants is critical to its performance against target pests. Samples from Immokalee fine sand (IFS) were used for sorption kinetics and equilibria experiments. IMD kinetics data were described by the one-site mass transfer (OSMT) model and reached equilibrium between 6 and 12 h. Batch equilibrium and degradation studies revealed that IMD was weakly sorbed (K(OC) = 163-230) and persistent, with a half-life of 1.0-2.6 years. Consequently, IMD has the potential to leach below the citrus root zone after the soil-drench applications. PMID:25938475

  4. The β-ketoacyl-ACP synthase from Mycobacterium tuberculosis as potential drug targets.

    PubMed

    Singh, V; Mani, I; Chaudhary, D K; Somvanshi, P

    2011-01-01

    The continuous preventive measures and control of tuberculosis are often hampered by re-emergence of multi-drug-resistant (MDR) strains of Mycobacterium tuberculosis. A novel drug approach is desperately needed to combat the global threat posed by MDR strains. In spite of current advancement in biological techniques viz. microarray and proteomics data for tuberculosis, no such potent drug has been developed in the past decades yet. Therefore, mycolic acid is an essential constituent which is involved in the formation of cell wall of Mycobacterium species. The biosynthesis of mycolic acid is involved in two fatty acid synthase systems, the multifunctional polypeptide fatty acid synthase I (FASI) which performs de novo fatty acid synthesis and dissociate FASII system. FASII system consists of monofunctional enzymes and acyl carrier protein (ACP), elongating FASI products to long chain mycolic acid precursor. In this review, the β-ketoacyl-ACP synthases (fadH, kasA and kasB) are distinct and play a vital role in mycolic acid synthesis, cell wall synthesis, biofilm formation and also pathogenesis. On the basis of substantial observation we suggest that these enzymes may be used as promising and attractive targets for novel anti-TB drugs designing and discovery. PMID:21370994

  5. Plant lectin-like antibacterial proteins from phytopathogens Pseudomonas syringae and Xanthomonas citri.

    PubMed

    Ghequire, Maarten G K; Li, Wen; Proost, Paul; Loris, Remy; De Mot, René

    2012-08-01

    The genomes of Pseudomonas syringae pv. syringae 642 and Xanthomonas citri pv. malvacearum LMG 761 each carry a putative homologue of the plant lectin-like bacteriocin (llpA) genes previously identified in the rhizosphere isolate Pseudomonas putida BW11M1 and the biocontrol strain Pseudomonas fluorescens Pf-5. The respective purified recombinant proteins, LlpAPss642 and LlpAXcm761 , display genus-specific antibacterial activity across species boundaries. The inhibitory spectrum of the P. syringae bacteriocin overlaps partially with those of the P. putida and P. fluorescens LlpAs. Notably, Xanthomonas axonopodis pv. citri str. 306 secretes a protein identical to LlpAXcm761 . The functional characterization of LlpA proteins from two different phytopathogenic γ-proteobacterial species expands the lectin-like bacteriocin family beyond the Pseudomonas genus and suggests its involvement in competition among closely related plant-associated bacteria with different lifestyles. PMID:23760822

  6. The jumping plant-louse Diaphorina teucrii sp. nov. (Hemiptera, Liviidae) associated with Teucrium (Lamiaceae) and its parasitoid Tamarixia dorchinae sp. nov. (Hymenoptera, Eulophidae) from the Negev desert, Israel.

    PubMed

    Burckhardt, Daniel; Yefremova, Zoya; Yegorenkova, Ekaterina

    2015-01-01

    Adults and immatures of Diaphorina teucrii sp. nov. (Hemiptera, Liviidae, Euphyllurinae) and adults of Tamarixia dorchinae sp. nov. (Hymenoptera, Eulophidae, Tetrastichinae) from Israel are described, diagnosed and illustrated. D. teucrii sp. nov. develops on Teucrium capitatum (Lamiaceae), representing a family which was previously not recorded as a psyllid host from Israel, and is parasitised by Tamarixia dorchinae sp. nov. Identification keys are provided for the Diaphorina and Tamarixia species occurring in Israel. PMID:25781261

  7. Adjuvants to improve aerial control of the citrus mealybug Planococcus citri (Hemiptera: Pseudococcidae) using entomopathogenic nematodes.

    PubMed

    van Niekerk, S; Malan, A P

    2015-03-01

    The citrus mealybug, Planococcus citri, is a highly destructive pest of citrus, occurring only in the aerial parts of plants. Humidity will be one of the key factors to consider when using entomopathogenic nematodes (EPN) as biological control agents. Different adjuvants can be added to suspensions of EPNs, to improve control as a foliar application. An aqueous suspension containing Heterorhabditis zealandica and 0.3% Zeba® significantly increased P. citri mortality by 22% at 80% relative humidity (RH) with a temperature cycle starting at 22°C for 14 h and 11°C for 11 h. The same polymer formulation was tested for Steinernema yirgalemense and mortality of P. citri increased by 21% at 60% RH and by 27% at 80% RH. The addition of Nu-Film-P® and Zeba® to H. zealandica suspensions did not significantly retard application run-off on citrus leaves. The combination of Nu-Film-P® and Zeba®, however, was able to significantly retard sedimentation, increasing the average number of nematodes deposited on 2-cm2 leaf discs by 10 nematodes. In an aqueous suspension, nematodes settle rapidly to the bottom, resulting in an uneven distribution of nematodes. Xanthan gum, at a concentration of 0.2%, was highly effective at retarding sedimentation, with 72% of the initial nematode number still in suspension after 1 h. Zeba®, at a concentration of 0.3%, despite not being as effective as Xanthan gum, nevertheless still retarded sedimentation significantly. This is the first report of the potential of Nu-Film-P® and Zeba® to improve EPN performance against P. citri when used above ground in citrus orchards. PMID:25652668

  8. Invasion of insect cells by Spiroplasma citri involves spiralin relocalization and lectin/glycoconjugate-type interactions.

    PubMed

    Duret, Sybille; Batailler, Brigitte; Dubrana, Marie-Pierre; Saillard, Colette; Renaudin, Joël; Béven, Laure; Arricau-Bouvery, Nathalie

    2014-07-01

    Spiroplamas are helical, cell wall-less bacteria belonging to the Class Mollicutes, a group of microorganisms phylogenetically related to low G+C, Gram-positive bacteria. Spiroplasma species are all found associated with arthropods and a few, including Spiroplasma citri are pathogenic to plant. Thus S. citri has the ability to colonize cells of two very distinct hosts, the plant and the insect vector. While spiroplasmal factors involved in transmission by the leafhopper Circulifer haematoceps have been identified, their specific contribution to invasion of insect cells is poorly understood. In this study we provide evidence that the lipoprotein spiralin plays a major role in the very early step of cell invasion. Confocal laser scanning immunomicroscopy revealed a relocalization of spiralin at the contact zone of adhering spiroplasmas. The implication of a role for spiralin in adhesion to insect cells was further supported by adhesion assays showing that a spiralin-less mutant was impaired in adhesion and that recombinant spiralin triggered adhesion of latex beads. We also showed that cytochalasin D induced changes in the surface-exposed glycoconjugates, as inferred from the lectin binding patterns, and specifically improved adhesion of S. citri wild-type but not of the spiralin-less mutant. These results indicate that cytochalasin D exposes insect cell receptors of spiralin that are masked in untreated cells. In addition, competitive adhesion assays with lectins strongly suggest spiralin to exhibit glycoconjugate binding properties similar to that of the Vicia villosa agglutinin (VVA) lectin. PMID:24438161

  9. Molecular Effects of Irradiation (Cobalt-60) on the Control of Panonychus citri (Acari: Tetranychidae)

    PubMed Central

    Zhang, Ke; Luo, Lingyan; Chen, Xieting; Hu, Meiying; Hu, Qiongbo; Gong, Liang; Weng, Qunfang

    2015-01-01

    The effective dose of irradiation to control pest mites in quarantine has been studied extensively, but the molecular mechanisms underlying the effects of the irradiation on mites are largely unknown. In this study, exposure to 400 Gy of γ rays had significant (p < 0.05) effects on the adult survival, fecundity and egg viability of Panonychus citri. The irradiation caused the degradation of the DNA of P. citri adults and damaged the plasma membrane system of the egg, which led to condensed nucleoli and gathered yolk. Additionally, the transcriptomes and gene expression profiles between irradiated and non-irradiated mites were compared, and three digital gene expression libraries were assembled and analyzed. The differentially expressed genes were putatively involved in apoptosis, cell death and the cell cycle. Finally, the expression profiles of some related genes were studied using quantitative real-time PCR. Our study provides valuable information on the changes in the transcriptome of irradiated P. citri, which will facilitate a better understanding of the molecular mechanisms that cause the sterility induced by irradiation. PMID:26569230

  10. Molecular Effects of Irradiation (Cobalt-60) on the Control of Panonychus citri (Acari: Tetranychidae).

    PubMed

    Zhang, Ke; Luo, Lingyan; Chen, Xieting; Hu, Meiying; Hu, Qiongbo; Gong, Liang; Weng, Qunfang

    2015-01-01

    The effective dose of irradiation to control pest mites in quarantine has been studied extensively, but the molecular mechanisms underlying the effects of the irradiation on mites are largely unknown. In this study, exposure to 400 Gy of γ rays had significant (p < 0.05) effects on the adult survival, fecundity and egg viability of Panonychus citri. The irradiation caused the degradation of the DNA of P. citri adults and damaged the plasma membrane system of the egg, which led to condensed nucleoli and gathered yolk. Additionally, the transcriptomes and gene expression profiles between irradiated and non-irradiated mites were compared, and three digital gene expression libraries were assembled and analyzed. The differentially expressed genes were putatively involved in apoptosis, cell death and the cell cycle. Finally, the expression profiles of some related genes were studied using quantitative real-time PCR. Our study provides valuable information on the changes in the transcriptome of irradiated P. citri, which will facilitate a better understanding of the molecular mechanisms that cause the sterility induced by irradiation. PMID:26569230

  11. Formic and acetic acids in degradation products of plant volatiles elicit olfactory and behavorial responses from an insect vector

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae) vectors the bacterial pathogen presumed to be the etiological agent of citrus greening disease, Huanglongbing (HLB), a major threat to citrus industry worldwide. We studied antennal and behavioral responses of Diaphorina citri...

  12. The relevance of Murraya paniculata and related species as potential hosts and inoculum reservoirs of Candidatus Liberibacter asiaticus, causal agent of Huanglongbing (HLB)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), considered the most serious insect-vectored bacterial disease of citrus, is transmitted in nature by the Asian citrus psyllid Diaphorina citri and the African citrus psyllid Trioza erytreae. Diaphorina citri was discovered in southern Florida in 1998 and the HLB disease in 2005...

  13. Gene response to stress in the Asian citrus psyllid (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transcriptional responses of the Asian citrus psyllid, Diaphorina citri, under three stress factors were investigated: physical wounding, heat stress, and exposure to low doses of the insecticide imidacloprid. The Asian citrus psyllid, Diaphorina citri, is a vector of the phloem-inhabiting bacterium...

  14. Ontogenic variation in citrus flush shoots and its relation with host plant finding and acceptance by Asian citrus psyllid (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae) is a destructive insect mainly because it vectors the bacterial pathogens that cause the deadly and incurable citrus greening disease. Diaphorina citri adult females lay eggs and immature development occurs exclusively on new flush sh...

  15. XbmR, a new transcription factor involved in the regulation of chemotaxis, biofilm formation and virulence in Xanthomonas citri subsp. citri.

    PubMed

    Yaryura, Pablo M; Conforte, Valeria P; Malamud, Florencia; Roeschlin, Roxana; de Pino, Verónica; Castagnaro, Atilio P; McCarthy, Yvonne; Dow, J Maxwell; Marano, María R; Vojnov, Adrián A

    2015-11-01

    Xanthomonas citri subsp. citri (Xcc) is the causal agent of citrus canker. Biofilm formation on citrus leaves plays an important role in epiphytic survival of Xcc. Biofilm formation is affected by transposon insertion in XAC3733, which encodes a transcriptional activator of the NtrC family, not linked to a gene encoding a sensor protein, thus could be considered as an 'orphan' regulator whose function is poorly understood in Xanthomonas spp. Here we show that mutation of XAC3733 (named xbmR) resulted in impaired structural development of the Xcc biofilm, loss of chemotaxis and reduced virulence in grapefruit plants. All defective phenotypes were restored to wild-type levels by the introduction of PA2567 from Pseudomonas aeruginosa, which encodes a phosphodiesterase active in the degradation of cyclic diguanosine monophosphate (c-di-GMP). A knockout of xbmR led to a substantial downregulation of fliA that encodes a σ(28) transcription factor, as well as fliC and XAC0350 which are potential member of the σ(28) regulon. XAC0350 encodes an HD-GYP domain c-di-GMP phosphodiesterase. These findings suggest that XbmR is a key regulator of flagellar-dependent motility and chemotaxis exerting its action through a regulatory pathway that involves FliA and c-di-GMP. PMID:25346091

  16. Bridgehead invasion of a monomorphic plant pathogenic bacterium: Xanthomonas citri pv. citri, an emerging citrus pathogen in Mali and Burkina Faso.

    PubMed

    Leduc, A; Traoré, Y N; Boyer, K; Magne, M; Grygiel, P; Juhasz, C C; Boyer, C; Guerin, F; Wonni, I; Ouedraogo, L; Vernière, C; Ravigné, V; Pruvost, O

    2015-11-01

    Molecular epidemiology studies further our understanding of migrations of phytopathogenic bacteria, the major determining factor in their emergence. Asiatic citrus canker, caused by Xanthomonas citri pv. citri, was recently reported in Mali and Burkina Faso, a region remote from other contaminated areas. To identify the origin and pathways of these emergences, we used two sets of markers, minisatellites and microsatellites, for investigating different evolutionary scales. Minisatellite typing suggested the introduction of two groups of strains in Mali (DAPC 1 and DAPC 2), consistent with microsatellite typing. DAPC 2 was restricted to Bamako district, whereas DAPC 1 strains were found much more invasive. The latter strains formed a major clonal complex based on microsatellite data with the primary and secondary founders detected in commercial citrus nurseries and orchards. This suggests that human activities played a major role in the spread of DAPC 1 strains via the movement of contaminated propagative material, further supported by the frequent lack of differentiation between populations from geographically distant nurseries and orchards. Approximate Bayesian Computation analyses supported the hypothesis that strains from Burkina Faso resulted from a bridgehead invasion from Mali. Multi-locus variable number of tandem repeat analysis and Approximate Bayesian Computation are useful for understanding invasion routes and pathways of monomorphic bacterial pathogens. PMID:25866121

  17. Chaplain Documentation and the Electronic Medical Record: A Survey of ACPE Residency Programs.

    PubMed

    Tartaglia, Alexander; Dodd-McCue, Diane; Ford, Timothy; Demm, Charles; Hassell, Alma

    2016-01-01

    This study explores the extent to which chaplaincy departments at ACPE-accredited residency programs make use of the electronic medical record (EMR) for documentation and training. Survey data solicited from 219 programs with a 45% response rate and interview findings from 11 centers demonstrate a high level of usage of the EMR as well as an expectation that CPE residents document each patient/family encounter. Centers provided considerable initial training, but less ongoing monitoring of chaplain documentation. Centers used multiple sources to develop documentation tools for the EMR. One center was verified as having created the spiritual assessment component of the documentation tool from a peer reviewed published model. Interviews found intermittent use of the student chart notes for educational purposes. One center verified a structured manner of monitoring chart notes as a performance improvement activity. Findings suggested potential for the development of a standard documentation tool for chaplain charting and training. PMID:26168408

  18. A Project Management Approach to an ACPE Accreditation Self-study

    PubMed Central

    Iwanowicz, Susan L.; Bailie, George R.; Clarke, David W.; McGraw, Patrick S.

    2007-01-01

    In preparation for an on-site evaluation and accreditation by the American Council on Pharmaceutical Education (ACPE), the Albany College of Pharmacy employed project management techniques to complete a comprehensive self-study. A project lifecycle approach, including planning, production, and turnover phases, was used by the project's Self-Study Steering Committee. This approach, with minimal disruption to college operations, resulted in the completion of the self-study process on schedule. Throughout the project, the Steering Committee maintained a log of functions that either were executed successfully or in hindsight, could have been improved. To assess the effectiveness of the project management approach to the the self-study process, feedback was obtained from the College community through a poststudy survey. This feedback, coupled with the Steering Committee's data on possible improvements, form the basis for the lessons learned during this self-study process. PMID:17533432

  19. Potential of South African entomopathogenic nematodes (Heterorhabditidae and Steinernematidae) for control of the citrus mealybug, Planococcus citri (Pseudococcidae).

    PubMed

    van Niekerk, Sonnica; Malan, Antoinette P

    2012-10-01

    Planococcus citri, the citrus mealybug, is the most important species of mealybug known to infest citrus in South Africa. Various laboratory bioassays were conducted to determine the potential of entomopathogenic nematodes to control P. citri. Adult female P. citri were screened for susceptibility to six indigenous nematode species. P. citri was found to be most susceptible to Steinernema yirgalemense and Heterorhabditis zealandica, causing 97% and 91% mortality, respectively. The development of nematodes after infecting adult female P. citri showed both H. zealandica and S. yirgalemense were able to complete their life cycles inside the host. Further bioassays illustrated a linear relationship between mealybug mortality and the concentration of nematodes applied, with the highest level of control using a concentration of 80 infective juveniles (IJs)/insect. As nematodes would be used as an above-ground application to control P. citri in citrus orchards, available water is a major limiting factor. Insecticidal activity proved to be dependent on the available surface moisture after nematode application. The water activity (a(w)) bioassay indicated that S. yirgalemense to be two times more tolerant to lower levels of free water, with a(w50)=0.96 and a(w90)=0.99, compared to H. zealandica with a(w50)=0.98 and a(w)90=1.0. After application, nematodes have a limited time frame in which to locate and infect hosts, as the level of available free water gradually decreases, as trees dry out. S. yirgalemense proved able to locate and infect P. citri quicker than H. zealandica. Nematode activity was not significantly affected when exposed to 15°C, 20°C and 25°C. IJs were able to infect P. citri at an exposure time as short as half an hour. Results also showed that the first 2-4h post application is the most decisive time for establishing successful infection of mealybugs. This is the first report on the potential use of nematodes for the control of P. citri. PMID:22884676

  20. Evaluation of the remineralization capacity of CPP-ACP containing fluoride varnish by different quantitative methods

    PubMed Central

    SAVAS, Selcuk; KAVRÌK, Fevzi; KUCUKYÌLMAZ, Ebru

    2016-01-01

    ABSTRACT Objective The aim of this study was to evaluate the efficacy of CPP-ACP containing fluoride varnish for remineralizing white spot lesions (WSLs) with four different quantitative methods. Material and Methods Four windows (3x3 mm) were created on the enamel surfaces of bovine incisor teeth. A control window was covered with nail varnish, and WSLs were created on the other windows (after demineralization, first week and fourth week) in acidified gel system. The test material (MI Varnish) was applied on the demineralized areas, and the treated enamel samples were stored in artificial saliva. At the fourth week, the enamel surfaces were tested by surface microhardness (SMH), quantitative light-induced fluorescence-digital (QLF-D), energy-dispersive spectroscopy (EDS) and laser fluorescence (LF pen). The data were statistically analyzed (α=0.05). Results While the LF pen measurements showed significant differences at baseline, after demineralization, and after the one-week remineralization period (p<0.05), the difference between the 1- and 4-week was not significant (p>0.05). With regards to the SMH and QLF-D analyses, statistically significant differences were found among all the phases (p<0.05). After the 1- and 4-week treatment periods, the calcium (Ca) and phosphate (P) concentrations and Ca/P ratio were higher compared to those of the demineralization surfaces (p<0.05). Conclusion CPP-ACP containing fluoride varnish provides remineralization of WSLs after a single application and seems suitable for clinical use. PMID:27383699

  1. Rhamnolipid and poly (hydrozyalkanoate) biosynthesis in 3-hydrozyacyl-ACP:COA transacylase (phaG) - knockouts of pseudomonas chloroaphis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 3-hydroxyacyl-ACP:CoA transacylase gene (phaG(Pc30761)) of P. chlororaphis NRRL B-30761 was cloned and analyzed. The nucleotide and translated amino-acid sequences of phaG(Pc30761) had 99% identities (at 100% query coverage) with the phaG gene of P. fluorescens O6. Two phaG-knockout strains of...

  2. Design and Synthesis of 2-Pyridones as Novel Inhibitors of the Bacillus Anthracis Enoyl–ACP Reductase

    PubMed Central

    Tipparaju, Suresh K.; Joyasawal, Sipak; Forrester, Sara; Mulhearn, Debbie C.; Pegan, Scott; Johnson, Michael E.; Mesecar, Andrew D.; Kozikowski, Alan P.

    2008-01-01

    Enoyl-ACP reductase (ENR), the product of the FabI gene, from Bacillus anthracis (BaENR) is responsible for catalyzing the final step of bacterial fatty acid biosynthesis. A number of novel 2-pyridone derivatives were synthesized and shown to be potent inhibitors of BaENR. PMID:18499454

  3. Expression Patterns of Genes Involved in the Defense and Stress Response of Spiroplasma citri Infected Madagascar Periwinkle Catharanthus roseus

    PubMed Central

    Nejat, Naghmeh; Vadamalai, Ganesan; Dickinson, Matthew

    2012-01-01

    Madagascar periwinkle is an ornamental and a medicinal plant, and is also an indicator plant that is highly susceptible to phytoplasma and spiroplasma infections from different crops. Periwinkle lethal yellows, caused by Spiroplasma citri, is one of the most devastating diseases of periwinkle. The response of plants to S. citri infection is very little known at the transcriptome level. In this study, quantitative real-time PCR (RT-qPCR) was used to investigate the expression levels of four selected genes involved in defense and stress responses in naturally and experimentally Spiroplasma citri infected periwinkles. Strictosidine β-glucosidase involved in terpenoid indole alkaloids (TIAs) biosynthesis pathway showed significant upregulation in experimentally and naturally infected periwinkles. The transcript level of extensin increased in leaves of periwinkles experimentally infected by S. citri in comparison to healthy ones. A similar level of heat shock protein 90 and metallothionein expression was observed in healthy, naturally and experimentally spiroplasma-diseased periwinkles. Overexpression of Strictosidine β-glucosidase demonstrates the potential utility of this gene as a host biomarker to increase the fidelity of S. citri detection and can also be used in breeding programs to develop stable disease-resistance varieties. PMID:22408455

  4. Microleakage of Three Types of Glass Ionomer Cement Restorations: Effect of CPP-ACP Paste Tooth Pretreatment

    PubMed Central

    Doozandeh, Maryam; Shafiei, Fereshteh; Alavi, Mostafa

    2015-01-01

    Statement of the Problem Casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) increases the mineral content of tooth structure. This may enhance the chemical bonding of glass ionomer cements (GIC) and marginal sealing of their restorations. Purpose The aim of this study was to evaluate the effect of CPP-ACP paste pretreatment on the microleakage of three types of GIC. Materials and Method In this study, 72 Class V cavities were prepared on the buccal and lingual surfaces of molars with occlusal margins in enamel and gingival margins in root. The cavities were divided into 6 groups. Cavities in group 1 and 2 were restored with Fuji II, group 3 and 4 with Fuji II LC, and group 5 and 6 with Ketac N100 with respect to the manufacturers’ instructions. In groups 2, 4 and 6, CPP-ACP containing paste (MI paste) was placed into the cavities for 3 minutes before being filled with GIC. The teeth were thermocycled, stained with dye, sectioned, and scored for microleakage under stereomicroscope. Kruskall-Wallis and Chi-Square tests were used to analyze the data. Result There were no statistically significant differences between the control and the CPP-ACP pretreatment groups in enamel and dentin margins. In pairwise comparisons, there were no significant differences between the control and the experimental groups in enamel margin, and in dentin margins of G1 and 2, G5 and 6; however, a significant differences was detected in dentin margins between G3 and 4 (p= 0.041). Conclusion CPP-ACP paste pretreatment did not affect the microleakage of Fuji II and Ketac N100 in enamel or dentin, but decreased the microleakage in dentine margins of Fuji II LC when cavity conditioner was applied before surface treatment. PMID:26331147

  5. The Acid Phosphatase-Encoding Gene GmACP1 Contributes to Soybean Tolerance to Low-Phosphorus Stress

    PubMed Central

    Hao, Derong; Wang, Hui; Kan, Guizhen; Jin, Hangxia; Yu, Deyue

    2014-01-01

    Phosphorus (P) is essential for all living cells and organisms, and low-P stress is a major factor constraining plant growth and yield worldwide. In plants, P efficiency is a complex quantitative trait involving multiple genes, and the mechanisms underlying P efficiency are largely unknown. Combining linkage analysis, genome-wide and candidate-gene association analyses, and plant transformation, we identified a soybean gene related to P efficiency, determined its favorable haplotypes and developed valuable functional markers. First, six major genomic regions associated with P efficiency were detected by performing genome-wide associations (GWAs) in various environments. A highly significant region located on chromosome 8, qPE8, was identified by both GWAs and linkage mapping and explained 41% of the phenotypic variation. Then, a regional mapping study was performed with 40 surrounding markers in 192 diverse soybean accessions. A strongly associated haplotype (P = 10−7) consisting of the markers Sat_233 and BARC-039899-07603 was identified, and qPE8 was located in a region of approximately 250 kb, which contained a candidate gene GmACP1 that encoded an acid phosphatase. GmACP1 overexpression in soybean hairy roots increased P efficiency by 11–20% relative to the control. A candidate-gene association analysis indicated that six natural GmACP1 polymorphisms explained 33% of the phenotypic variation. The favorable alleles and haplotypes of GmACP1 associated with increased transcript expression correlated with higher enzyme activity. The discovery of the optimal haplotype of GmACP1 will now enable the accurate selection of soybeans with higher P efficiencies and improve our understanding of the molecular mechanisms underlying P efficiency in plants. PMID:24391523

  6. Structural and Physiological Analyses of the Alkanesulphonate-Binding Protein (SsuA) of the Citrus Pathogen Xanthomonas citri

    PubMed Central

    Tófoli de Araújo, Fabiano; Bolanos-Garcia, Victor M.; Pereira, Cristiane T.; Sanches, Mario; Oshiro, Elisa E.; Ferreira, Rita C. C.; Chigardze, Dimitri Y.; Barbosa, João Alexandre Gonçalves; de Souza Ferreira, Luís Carlos; Benedetti, Celso E.; Blundell, Tom L.; Balan, Andrea

    2013-01-01

    Background The uptake of sulphur-containing compounds plays a pivotal role in the physiology of bacteria that live in aerobic soils where organosulfur compounds such as sulphonates and sulphate esters represent more than 95% of the available sulphur. Until now, no information has been available on the uptake of sulphonates by bacterial plant pathogens, particularly those of the Xanthomonas genus, which encompasses several pathogenic species. In the present study, we characterised the alkanesulphonate uptake system (Ssu) of Xanthomonas axonopodis pv. citri 306 strain (X. citri), the etiological agent of citrus canker. Methodology/Principal Findings A single operon-like gene cluster (ssuEDACB) that encodes both the sulphur uptake system and enzymes involved in desulphurisation was detected in the genomes of X. citri and of the closely related species. We characterised X. citri SsuA protein, a periplasmic alkanesulphonate-binding protein that, together with SsuC and SsuB, defines the alkanesulphonate uptake system. The crystal structure of SsuA bound to MOPS, MES and HEPES, which is herein described for the first time, provides evidence for the importance of a conserved dipole in sulphate group coordination, identifies specific amino acids interacting with the sulphate group and shows the presence of a rather large binding pocket that explains the rather wide range of molecules recognised by the protein. Isolation of an isogenic ssuA-knockout derivative of the X. citri 306 strain showed that disruption of alkanesulphonate uptake affects both xanthan gum production and generation of canker lesions in sweet orange leaves. Conclusions/Significance The present study unravels unique structural and functional features of the X. citri SsuA protein and provides the first experimental evidence that an ABC uptake system affects the virulence of this phytopathogen. PMID:24282519

  7. Biomimetic remineralization of demineralized dentine using scaffold of CMC/ACP nanocomplexes in an in vitro tooth model of deep caries.

    PubMed

    Chen, Zhen; Cao, Shansong; Wang, Haorong; Li, Yanqiu; Kishen, Anil; Deng, Xuliang; Yang, Xiaoping; Wang, Yinghui; Cong, Changhong; Wang, Huajun; Zhang, Xu

    2015-01-01

    Currently, it is still a tough task for dentists to remineralize dentine in deep caries. The aim of this study was to remineralize demineralized dentine in a tooth model of deep caries using nanocomplexes of carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP) based on mimicking the stabilizing effect of dentine matrix protein 1 (DMP1) on ACP in the biomineralization of dentine. The experimental results indicate that CMC can stabilize ACP to form nanocomplexes of CMC/ACP, which is able to be processed into scaffolds by lyophilization. In the single-layer collagen model, ACP nanoparticles are released from scaffolds of CMC/ACP nanocomplexes dissolved and then infiltrate into collagen fibrils via the gap zones (40 nm) to accomplish intrafibrillar mineralization of collagen. With this method, the completely demineralized dentine was partially remineralized in the tooth mode. This is a bottom-up remineralizing strategy based on non-classical crystallization theory. Since nanocomplexes of CMC/ACP show a promising effect of remineralization on demineralized dentine via biomimetic strategy, thereby preserving dentinal tissue to the maximum extent possible, it would be a potential indirect pulp capping (IPC) material for the management of deep caries during vital pulp therapy based on the concept of minimally invasive dentistry (MID). PMID:25587986

  8. Biomimetic Remineralization of Demineralized Dentine Using Scaffold of CMC/ACP Nanocomplexes in an In Vitro Tooth Model of Deep Caries

    PubMed Central

    Chen, Zhen; Cao, Shansong; Wang, Haorong; Li, Yanqiu; Kishen, Anil; Deng, Xuliang; Yang, Xiaoping; Wang, Yinghui; Cong, Changhong; Wang, Huajun; Zhang, Xu

    2015-01-01

    Currently, it is still a tough task for dentists to remineralize dentine in deep caries. The aim of this study was to remineralize demineralized dentine in a tooth model of deep caries using nanocomplexes of carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP) based on mimicking the stabilizing effect of dentine matrix protein 1 (DMP1) on ACP in the biomineralization of dentine. The experimental results indicate that CMC can stabilize ACP to form nanocomplexes of CMC/ACP, which is able to be processed into scaffolds by lyophilization. In the single-layer collagen model, ACP nanoparticles are released from scaffolds of CMC/ACP nanocomplexes dissolved and then infiltrate into collagen fibrils via the gap zones (40 nm) to accomplish intrafibrillar mineralization of collagen. With this method, the completely demineralized dentine was partially remineralized in the tooth mode. This is a bottom-up remineralizing strategy based on non-classical crystallization theory. Since nanocomplexes of CMC/ACP show a promising effect of remineralization on demineralized dentine via biomimetic strategy, thereby preserving dentinal tissue to the maximum extent possible, it would be a potential indirect pulp capping (IPC) material for the management of deep caries during vital pulp therapy based on the concept of minimally invasive dentistry (MID). PMID:25587986

  9. Overexpression of the olive acyl carrier protein gene (OeACP1) produces alterations in fatty acid composition of tobacco leaves.

    PubMed

    De Marchis, Francesca; Valeri, Maria Cristina; Pompa, Andrea; Bouveret, Emmanuelle; Alagna, Fiammetta; Grisan, Simone; Stanzione, Vitale; Mariotti, Roberto; Cultrera, Nicolò; Baldoni, Luciana; Bellucci, Michele

    2016-02-01

    Taking into account that fatty acid (FA) biosynthesis plays a crucial role in lipid accumulation in olive (Olea europaea L.) mesocarp, we investigated the effect of olive acyl carrier protein (ACP) on FA composition by overexpressing an olive ACP cDNA in tobacco plants. The OeACP1.1A cDNA was inserted in the nucleus or in the chloroplast DNA of different tobacco plants, resulting in extensive transcription of the transgenes. The transplastomic plants accumulated lower olive ACP levels in comparison to nuclear-transformed plants. Moreover, the phenotype of the former plants was characterized by pale green/white cotyledons with abnormal chloroplasts, delayed germination and reduced growth. We suggest that the transplastomic phenotype was likely caused by inefficient olive ACP mRNA translation in chloroplast stroma. Conversely, total lipids from leaves of nuclear transformants expressing high olive ACP levels showed a significant increase in oleic acid (18:1) and linolenic acid (18:3), and a concomitant significant reduction of hexadecadienoic acid (16:2) and hexadecatrienoic acid (16:3). This implies that in leaves of tobacco transformants, as likely in the mesocarp of olive fruit, olive ACP not only plays a general role in FA synthesis, but seems to be specifically involved in chain length regulation forwarding the elongation to C18 FAs and the subsequent desaturation to 18:1 and 18:3. PMID:26560313

  10. Solution Structure of 4′-Phosphopantetheine - GmACP3 from Geobacter metallireducens: A Specialized Acyl Carrier Protein with Atypical Structural Features and a Putative Role in Lipopolysaccharide Biosynthesis†

    PubMed Central

    Ramelot, Theresa A.; Smola, Matthew J.; Lee, Hsiau-Wei; Ciccosanti, Colleen; Hamilton, Keith; Acton, Thomas B.; Xiao, Rong; Everett, John K.; Prestegard, James H.; Montelione, Gaetano T.; Kennedy, Michael A.

    2011-01-01

    GmACP3 from Geobacter metallireducens is a specialized acyl carrier protein (ACP) whose gene, gmet_2339, is located near genes encoding many proteins involved in lipopolysaccharide (LPS) biosynthesis, indicating a likely function for GmACP3 in LPS production. By overexpression in Escherichia coli, about 50% holo-GmACP3 and 50% apo-GmACP3 were obtained. Apo-GmACP3 exhibited slow precipitation and non-monomeric behavior by 15N NMR relaxation measurements. Addition of 4′-phosphopantetheine (4′-PP) via enzymatic conversion by E. coli holo-ACP synthase, resulted in stable >95% holo-GmACP3 that was characterized as monomeric by 15N relaxation measurements and had no indication of conformational exchange. We have determined a high-resolution solution structure of holo-GmACP3 by standard NMR methods, including refinement with two sets of NH residual dipolar couplings, allowing for a detailed structural analysis of the interactions between 4′-PP and GmACP3. Whereas the overall four helix bundle topology is similar to previously solved ACP structures, this structure has unique characteristics, including an ordered 4′-PP conformation that places the thiol at the entrance to a central hydrophobic cavity near a conserved hydrogen-bonded Trp-His pair. These residues are part of a conserved WDSLxH/N motif found in GmACP3 and it’s orthologs. The helix locations and the large hydrophobic cavity are more similar to medium- and long-chain acyl-ACPs than to other apo- and holo-ACP structures. Taken together, structural characterization along with bioinformatic analysis of nearby genes suggest that GmACP3 is involved in lipid A acylation, possibly by atypical long-chain hydroxy fatty acids, and potentially involved in synthesis of secondary metabolites. PMID:21235239

  11. Involvement of Three Esterase Genes from Panonychus citri (McGregor) in Fenpropathrin Resistance.

    PubMed

    Shen, Xiao-Min; Liao, Chong-Yu; Lu, Xue-Ping; Wang, Zhe; Wang, Jin-Jun; Dou, Wei

    2016-01-01

    The citrus red mite, Panonychus citri (McGregor), is a major citrus pest with a worldwide distribution and an extensive record of pesticide resistance. However, the underlying molecular mechanism associated with fenpropathrin resistance in this species have not yet been reported. In this study, synergist triphenyl phosphate (TPP) dramatically increased the toxicity of fenpropathrin, suggesting involvement of carboxylesterases (CarEs) in the metabolic detoxification of this insecticide. The subsequent spatiotemporal expression pattern analysis of PcE1, PcE7 and PcE9 showed that three CarEs genes were all over-expressed after insecticide exposure and higher transcripts levels were observed in different field resistant strains of P. citri. Heterologous expression combined with 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetra-zolium bromide (MTT) cytotoxicity assay in Spodoptera frugiperda (Sf9) cells revealed that PcE1-, PcE7- or PcE9-expressing cells showed significantly higher cytoprotective capability than parental Sf9 cells against fenpropathrin, demonstrating that PcEs probably detoxify fenpropathrin. Moreover, gene silencing through the method of leaf-mediated dsRNA feeding followed by insecticide bioassay increased the mortalities of fenpropathrin-treated mites by 31% (PcE1), 27% (PcE7) and 22% (PcE9), respectively, after individual PcE gene dsRNA treatment. In conclusion, this study provides evidence that PcE1, PcE7 and PcE9 are functional genes mediated in fenpropathrin resistance in P. citri and enrich molecular understanding of CarEs during the resistance development of the mite. PMID:27548163

  12. Involvement of Three Esterase Genes from Panonychus citri (McGregor) in Fenpropathrin Resistance

    PubMed Central

    Shen, Xiao-Min; Liao, Chong-Yu; Lu, Xue-Ping; Wang, Zhe; Wang, Jin-Jun; Dou, Wei

    2016-01-01

    The citrus red mite, Panonychus citri (McGregor), is a major citrus pest with a worldwide distribution and an extensive record of pesticide resistance. However, the underlying molecular mechanism associated with fenpropathrin resistance in this species have not yet been reported. In this study, synergist triphenyl phosphate (TPP) dramatically increased the toxicity of fenpropathrin, suggesting involvement of carboxylesterases (CarEs) in the metabolic detoxification of this insecticide. The subsequent spatiotemporal expression pattern analysis of PcE1, PcE7 and PcE9 showed that three CarEs genes were all over-expressed after insecticide exposure and higher transcripts levels were observed in different field resistant strains of P. citri. Heterologous expression combined with 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetra-zolium bromide (MTT) cytotoxicity assay in Spodoptera frugiperda (Sf9) cells revealed that PcE1-, PcE7- or PcE9-expressing cells showed significantly higher cytoprotective capability than parental Sf9 cells against fenpropathrin, demonstrating that PcEs probably detoxify fenpropathrin. Moreover, gene silencing through the method of leaf-mediated dsRNA feeding followed by insecticide bioassay increased the mortalities of fenpropathrin-treated mites by 31% (PcE1), 27% (PcE7) and 22% (PcE9), respectively, after individual PcE gene dsRNA treatment. In conclusion, this study provides evidence that PcE1, PcE7 and PcE9 are functional genes mediated in fenpropathrin resistance in P. citri and enrich molecular understanding of CarEs during the resistance development of the mite. PMID:27548163

  13. A survey of FLS2 genes from multiple citrus species identifies candidates for enhancing disease resistance to Xanthomonas citri ssp. citri.

    PubMed

    Shi, Qingchun; Febres, Vicente J; Jones, Jeffrey B; Moore, Gloria A

    2016-01-01

    Pathogen-associated molecular patterns (PAMPs)-triggered immunity (PTI) is an important component of plant innate immunity. In a previous study, we showed that the PAMP flg22 from Xanthomonas citri ssp. citri (Xflg22), the causal agent of citrus canker, induced PTI in citrus, which correlated with the observed levels of canker resistance. Here, we identified and sequenced two bacterial flagellin/flg22 receptors (FLS2-1 and FLS2-2) from 'Duncan' grapefruit (Citrus paradisi, CpFLS2-1 and CpFLS2-2) and 'Sun Chu Sha' mandarin (C. reticulata, CrFLS2-1 and CrFLS2-2). We were able to isolate only one FLS2 from 'Nagami' kumquat (Fortunella margarita, FmFLS2-1) and gene flanking sequences suggest a rearrangement event that resulted in the deletion of FLS2-2 from the genome. Phylogenetic analysis, gene structure and presence of critical amino acid domains all indicate we identified the true FLS2 genes in citrus. FLS2-2 was more transcriptionally responsive to Xflg22 than FLS2-1, with induced expression levels higher in canker-resistant citrus than in susceptible ones. Interestingly, 'Nagami' kumquat showed the highest FLS2-1 steady-state expression levels, although it was not induced by Xflg22. We selected FmFLS2-1, CrFLS2-2 and CpFLS2-2 to further evaluate their capacity to enhance bacterial resistance using Agrobacterium-mediated transient expression assays. Both FmFLS2-1 and CrFLS2-2, the two proteins from canker-resistant species, conferred stronger Xflg22 responses and reduced canker symptoms in leaves of the susceptible grapefruit genotype. These two citrus genes will be useful resources to enhance PTI and achieve resistance against canker and possibly other bacterial pathogens in susceptible citrus types. PMID:27222722

  14. Comparative proteomic analysis reveals that T3SS, Tfp, and xanthan gum are key factors in initial stages of Citrus sinensis infection by Xanthomonas citri subsp. citri.

    PubMed

    Facincani, Agda P; Moreira, Leandro M; Soares, Márcia R; Ferreira, Cristiano B; Ferreira, Rafael M; Ferro, Maria I T; Ferro, Jesus A; Gozzo, Fabio C; de Oliveira, Julio C F

    2014-03-01

    The bacteria Xanthomonas citri subsp. citri (Xac) is the causal agent of citrus canker. The disease symptoms are characterized by localized host cell hyperplasia followed by tissue necrosis at the infected area. An arsenal of bacterial pathogenicity- and virulence-related proteins is expressed to ensure a successful infection process. At the post-genomic stage of Xac, we used a proteomic approach to analyze the proteins that are displayed differentially over time when the pathogen attacks the host plant. Protein extracts were prepared from infectious Xac grown in inducing medium (XAM1) for 24 h or from host citrus plants for 3 or 5 days after infection, detached times to evaluate the adaptation and virulence of the pathogen. The protein extracts were proteolyzed, and the peptides derived from tryptic digestion were investigated using liquid chromatography and tandem mass spectrometry. Changes in the protein expression profile were compared with the Xac genome and the proteome recently described under non-infectious conditions. An analysis of the proteome of Xac under infectious conditions revealed proteins directly involved in virulence such as the type III secretion system (T3SS) and effector proteins (T3SS-e), the type IV pilus (Tfp), and xanthan gum biosynthesis. Moreover, four new mutants related to proteins detected in the proteome and with different functions exhibited reduced virulence relative to the wild-type proteins. The results of the proteome analysis of infectious Xac define the processes of adaptation to the host and demonstrate the induction of the virulence factors of Xac involved in plant-pathogen interactions. PMID:24676796

  15. The dual nature of trehalose in citrus canker disease: a virulence factor for Xanthomonas citri subsp. citri and a trigger for plant defence responses.

    PubMed

    Piazza, Ainelén; Zimaro, Tamara; Garavaglia, Betiana S; Ficarra, Florencia A; Thomas, Ludivine; Marondedze, Claudius; Feil, Regina; Lunn, John E; Gehring, Chris; Ottado, Jorgelina; Gottig, Natalia

    2015-05-01

    Xanthomonas citri subsp. citri (Xcc) is a bacterial pathogen that causes citrus canker in susceptible Citrus spp. The Xcc genome contains genes encoding enzymes from three separate pathways of trehalose biosynthesis. Expression of genes encoding trehalose-6-phosphate synthase (otsA) and trehalose phosphatase (otsB) was highly induced during canker development, suggesting that the two-step pathway of trehalose biosynthesis via trehalose-6-phosphate has a function in pathogenesis. This pathway was eliminated from the bacterium by deletion of the otsA gene. The resulting XccΔotsA mutant produced less trehalose than the wild-type strain, was less resistant to salt and oxidative stresses, and was less able to colonize plant tissues. Gene expression and proteomic analyses of infected leaves showed that infection with XccΔotsA triggered only weak defence responses in the plant compared with infection with Xcc, and had less impact on the host plant's metabolism than the wild-type strain. These results suggested that trehalose of bacterial origin, synthesized via the otsA-otsB pathway, in Xcc, plays a role in modifying the host plant's metabolism to its own advantage but is also perceived by the plant as a sign of pathogen attack. Thus, trehalose biosynthesis has both positive and negative consequences for Xcc. On the one hand, it enables this bacterial pathogen to survive in the inhospitable environment of the leaf surface before infection and exploit the host plant's resources after infection, but on the other hand, it is a tell-tale sign of the pathogen's presence that triggers the plant to defend itself against infection. PMID:25770587

  16. Responsiveness of different citrus genotypes to the Xanthomonas citri ssp. citri-derived pathogen-associated molecular pattern (PAMP) flg22 correlates with resistance to citrus canker.

    PubMed

    Shi, Qingchun; Febres, Vicente J; Jones, Jeffrey B; Moore, Gloria A

    2015-06-01

    The bacterial agent of citrus canker disease (Xanthomonas citri ssp. citri, Xcc) has caused tremendous economic losses to the citrus industry around the world. Pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) is important to plant immunity. In this study, we compared the defence responses of citrus canker-resistant and citrus canker-susceptible genotypes to the Xcc-derived PAMP flg22 (Xflg22) by analysing the expression of 20 citrus defence-associated genes. We showed that, in the most resistant genotype, 'Nagami' kumquat, there was significant induction of several defence genes (EDS1, NDR1, PBS1, RAR1, SGT1, PAL1, NPR2 and NPR3) as early as 6 h and up to 72 h after Xflg22 treatment. At the other end of the spectrum, highly susceptible 'Duncan' grapefruit showed no induction of the same defence genes, even 120 h after treatment. Citrus genotypes with partial levels of resistance showed intermediate levels of transcriptional reprogramming that correlated with their resistance level. Xflg22 also triggered a rapid oxidative burst in all genotypes which was higher and accompanied by the induction of PTI marker genes (WRKY22 and GST1) only in the more resistant genotypes. Pretreatment with Xflg22 prior to Xcc inoculation inhibited bacterial growth in kumquat, but not in grapefruit. A flagellin-deficient Xcc strain (XccΔfliC) showed greater growth increase relative to wild-type Xcc in kumquat than in grapefruit. Taken together, our results indicate that Xflg22 initiates strong PTI in canker-resistant genotypes, but not in susceptible ones, and that a robust induction of PTI is an important component of citrus resistance to canker. PMID:25231217

  17. Radiosynthesis and biological evaluation of a novel enoyl-ACP reductase inhibitor for Staphylococcus aureus

    DOE PAGESBeta

    Wang, Hui; Lu, Yang; Liu, Li; Kim, Sung Won; Hooker, Jacob M.; Fowler, Joanna S.; Tonge, Peter J.

    2014-09-06

    Here we evaluated the pharmacokinetics (PK) and pharmacodynamics (PD) of PT119, a potent Staphylococcus aureus enoyl-ACP reductase (saFabI) inhibitor with a Ki value of 0.01 nM and a residence time of 750 min on the enzyme target in mice. PT119 was found to have promising antibacterial activity in two different S. aureus infection models: it caused a 3 log reduction in the CFU’s in a mouse thigh muscle infection model and increased the survival rate from 0% to 50% in a mouse systemic infection model. PT119 was then radiolabeled with carbon-11 to evaluate its biodistribution and PK in both healthymore » and S. aureus infected mice using positron emission tomography (PET). The biodistribution of [11C]PT119 and/or its labeled metabolites did not differ significantly between the healthy group and the infected group, and PT119 was found to distribute equally between serum and tissue during the ~1 h of analysis permitted by the carbon-11 half life. This approach provides important data for PK/PD modeling and is the first step in identifying radiotracers that can non-invasively image bacterial infection in vivo.« less

  18. Radiosynthesis and biological evaluation of a novel enoyl-ACP reductase inhibitor for Staphylococcus aureus

    SciTech Connect

    Wang, Hui; Lu, Yang; Liu, Li; Kim, Sung Won; Hooker, Jacob M.; Fowler, Joanna S.; Tonge, Peter J.

    2014-09-06

    Here we evaluated the pharmacokinetics (PK) and pharmacodynamics (PD) of PT119, a potent Staphylococcus aureus enoyl-ACP reductase (saFabI) inhibitor with a Ki value of 0.01 nM and a residence time of 750 min on the enzyme target in mice. PT119 was found to have promising antibacterial activity in two different S. aureus infection models: it caused a 3 log reduction in the CFU’s in a mouse thigh muscle infection model and increased the survival rate from 0% to 50% in a mouse systemic infection model. PT119 was then radiolabeled with carbon-11 to evaluate its biodistribution and PK in both healthy and S. aureus infected mice using positron emission tomography (PET). The biodistribution of [11C]PT119 and/or its labeled metabolites did not differ significantly between the healthy group and the infected group, and PT119 was found to distribute equally between serum and tissue during the ~1 h of analysis permitted by the carbon-11 half life. This approach provides important data for PK/PD modeling and is the first step in identifying radiotracers that can non-invasively image bacterial infection in vivo.

  19. Results of Second Outdoor Comparison Between Absolute Cavity Pyrgeometer (ACP) and Infrared Integrating Sphere (IRIS) Radiometer at PMOD (Presentation)

    SciTech Connect

    Reda, I.; Grobner, J.; Wacker, S.

    2014-01-01

    The Absolute Cavity Pyrgeometer (ACP) and InfraRed Integrating Sphere radiometer (IRIS) are developed to establish a world reference for calibrating pyrgeometers with traceability to SI units. The two radiometers are un-windowed with negligible spectral dependence, and traceable to SI units through the temperature scale (ITS-90). The second outdoor comparison between the two designs was held from September 30 to October 11, 2013 at the Physikalisch-Metorologisches Observatorium Davos (PMOD). The difference between the irradiance measured by ACP and that of the IRIS was within 1 W/m2 (3 IRISs: PMOD + Australia + Germany). From the first and second comparisons, a difference of 4-6 W/m2 was observed between the irradiance measured by ACP&IRIS and that of the interim World Infrared Standard Group (WISG). This presentation includes results from the first and second comparison in an effort to establish the world reference for pyrgeometer calibrations, a key deliverable for the World Meteorological Organization (WMO), and the DOE-ASR.

  20. Levels of Candidatus Liberibacter asiaticus and Xanthomonas citri in diverse citrus genotypes and relevance to potential transmission from pollinations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diseases huanglongbing (HLB, associated with Candidatus Liberibacter asiaticus, CLas) and Asian citrus canker (ACC, caused by Xanthomonas citri, Xcc) are widespread in Florida and many other citrus-growing areas, presenting unprecedented challenges for citrus breeding. Since HLB and ACC weaken ...

  1. Development and reproduction of Panonychus citri (Prostigmata: Tetranychidae) on different species and varieties of citrus plants.

    PubMed

    Zanardi, Odimar Zanuzo; Bordini, Gabriela Pavan; Franco, Aline Aparecida; de Morais, Matheus Rovere; Yamamoto, Pedro Takao

    2015-12-01

    The species and varieties of citrus plants that are currently grown can favor the population growth of the citrus red mite Panonychus citri (McGregor) (Prostigmata: Tetranychidae) and alter the pest management programs in citrus groves. In this study we evaluated, in the laboratory, the development and reproduction of P. citri and estimated its life table parameters when reared on four varieties of Citrus sinensis (L.) Osbeck (Valencia, Pera, Natal, and Hamlin), one variety of Citrus reticulata Blanco (Ponkan) and one variety of Citrus limon (L.) Burm. (Sicilian). The incubation period and egg viability were not affected by the host plant. However, the development and survival of the immature stage were significantly lower on Hamlin orange than on Valencia, Pera and Natal oranges, Ponkan mandarin and Sicilian lemon. The fecundity and oviposition period of females were lower on Hamlin orange than on the other hosts. Mites reared on Valencia orange and Sicilian lemon had a higher net reproductive rate (R 0 ), intrinsic growth rate (r) and finite rate of increase (λ), and a shorter interval between generations (T) than on Pera, Natal and Hamlin oranges and Ponkan mandarin. On the other hand, mites reared on Hamlin orange had the lowest R 0 , r and λ and the highest T among the hosts. Based on the results obtained we recommend that for Valencia orange and Sicilian lemon, the mite monitoring programs should be more intense to detect the initial infestation of pest, avoiding the damage in plants and the increase in production costs. PMID:26459376

  2. The relationship between PthA expression and the pathogenicity of Xanthomonas axonopodis pv. citri.

    PubMed

    Li, Na; Huang, Long; Liu, Liping; Li, Dazhi; Dai, Suming; Deng, Ziniu

    2014-02-01

    Citrus canker disease, caused by Xanthomonas axonopodis pv. citri, affects almost all citrus species and cultivars and hascaused severe damage to the citrus industry worldwide. PthA is considered the main pathogenesis effector of the pathogen. This research aimed to temporally and spatially analyze the expression of the PthA protein of the bactrium during its culture, and then try to understand the relationship between the PthA expression levels and the pathogenicity. The relationship between the expression of PthA and the pathogenicity of X. axonopodis pv. citri was fully investigated by using SDS-PAGE, Western blot, ELISA and field inoculation, It was found that bacteria cultured for 36 h had the highest expression of PthA and showed the most virulent pathogenicity. The conservation duration of the pathogen isolates influenced their PthA expression and the pathogenicity, and negative relationship between the duration and the expression of PthA and pathogenicity. When the stored pathogen bacteria were cultured in liquid LB medium, they were able to regain activated, showing higher PthA expression level and enhanced pathogenicity, even though the activity was inferior, in terms of both PthA expression and pathogenicity, than the freshly isolated ones. Seven isolates from different citrus orchards displayed almost identical protein expression profiles. It could conclude that the expressions of PthA was positively related to pathogenicity. PMID:24385299

  3. Acyl-ACP thioesterases from castor (Ricinus communis L.): an enzymatic system appropriate for high rates of oil synthesis and accumulation.

    PubMed

    Sánchez-García, Alicia; Moreno-Pérez, Antonio J; Muro-Pastor, Alicia M; Salas, Joaquín J; Garcés, Rafael; Martínez-Force, Enrique

    2010-06-01

    Acyl-acyl carrier protein (ACP) thioesterases are enzymes that terminate the intraplastidial fatty acid synthesis in plants by hydrolyzing the acyl-ACP intermediates and releasing free fatty acids to be incorporated into glycerolipids. These enzymes are classified in two families, FatA and FatB, which differ in amino acid sequence and substrate specificity. In the present work, both FatA and FatB thioesterases were cloned, sequenced and characterized from castor (Ricinus communis) seeds, a crop of high interest in oleochemistry. Single copies of FatA and FatB were found in castor resulting to be closely related with those of Jatropha curcas. The corresponding mature proteins were heterologously expressed in Escherichia coli for biochemical characterization after purification, resulting in high catalytic efficiency of RcFatA on oleoyl-ACP and palmitoleoyl-ACP and high efficiencies of RcFatB for oleoyl-ACP and palmitoyl-ACP. The expression profile of these genes displayed the highest levels in expanding tissues that typically are very active in lipid biosynthesis such as developing seed endosperm and young expanding leaves. The contribution of these two enzymes to the synthesis of castor oil is discussed. PMID:20382402

  4. A LOV protein modulates the physiological attributes of Xanthomonas axonopodis pv. citri relevant for host plant colonization.

    PubMed

    Kraiselburd, Ivana; Alet, Analía I; Tondo, María Laura; Petrocelli, Silvana; Daurelio, Lucas D; Monzón, Jesica; Ruiz, Oscar A; Losi, Aba; Orellano, Elena G

    2012-01-01

    Recent studies have demonstrated that an appropriate light environment is required for the establishment of efficient vegetal resistance responses in several plant-pathogen interactions. The photoreceptors implicated in such responses are mainly those belonging to the phytochrome family. Data obtained from bacterial genome sequences revealed the presence of photosensory proteins of the BLUF (Blue Light sensing Using FAD), LOV (Light, Oxygen, Voltage) and phytochrome families with no known functions. Xanthomonas axonopodis pv. citri is a Gram-negative bacterium responsible for citrus canker. The in silico analysis of the X. axonopodis pv. citri genome sequence revealed the presence of a gene encoding a putative LOV photoreceptor, in addition to two genes encoding BLUF proteins. This suggests that blue light sensing could play a role in X. axonopodis pv. citri physiology. We obtained the recombinant Xac-LOV protein by expression in Escherichia coli and performed a spectroscopic analysis of the purified protein, which demonstrated that it has a canonical LOV photochemistry. We also constructed a mutant strain of X. axonopodis pv. citri lacking the LOV protein and found that the loss of this protein altered bacterial motility, exopolysaccharide production and biofilm formation. Moreover, we observed that the adhesion of the mutant strain to abiotic and biotic surfaces was significantly diminished compared to the wild-type. Finally, inoculation of orange (Citrus sinensis) leaves with the mutant strain of X. axonopodis pv. citri resulted in marked differences in the development of symptoms in plant tissues relative to the wild-type, suggesting a role for the Xac-LOV protein in the pathogenic process. Altogether, these results suggest the novel involvement of a photosensory system in the regulation of physiological attributes of a phytopathogenic bacterium. A functional blue light receptor in Xanthomonas spp. has been described for the first time, showing an important

  5. A novel two-component response regulator links rpf with biofilm formation and virulence of Xanthomonas axonopodis pv. citri.

    PubMed

    Huang, Tzu-Pi; Lu, Kuan-Min; Chen, Yu-Hsuan

    2013-01-01

    Citrus bacterial canker caused by Xanthomonas axonopodis pv. citri is a serious disease that impacts citrus production worldwide, and X. axonopodis pv. citri is listed as a quarantine pest in certain countries. Biofilm formation is important for the successful development of a pathogenic relationship between various bacteria and their host(s). To understand the mechanisms of biofilm formation by X. axonopodis pv. citri strain XW19, the strain was subjected to transposon mutagenesis. One mutant with a mutation in a two-component response regulator gene that was deficient in biofilm formation on a polystyrene microplate was selected for further study. The protein was designated as BfdR for biofilm formation defective regulator. BfdR from strain XW19 shares 100% amino acid sequence identity with XAC1284 of X. axonopodis pv. citri strain 306 and 30-100% identity with two-component response regulators in various pathogens and environmental microorganisms. The bfdR mutant strain exhibited significantly decreased biofilm formation on the leaf surfaces of Mexican lime compared with the wild type strain. The bfdR mutant was also compromised in its ability to cause canker lesions. The wild-type phenotype was restored by providing pbfdR in trans in the bfdR mutant. Our data indicated that BfdR did not regulate the production of virulence-related extracellular enzymes including amylase, lipase, protease, and lecithinase or the expression of hrpG, rfbC, and katE; however, BfdR controlled the expression of rpfF in XVM2 medium, which mimics cytoplasmic fluids in planta. In conclusion, biofilm formation on leaf surfaces of citrus is important for canker development in X. axonopodis pv. citri XW19. The process is controlled by the two-component response regulator BfdR via regulation of rpfF, which is required for the biosynthesis of a diffusible signal factor. PMID:23626857

  6. A LOV Protein Modulates the Physiological Attributes of Xanthomonas axonopodis pv. citri Relevant for Host Plant Colonization

    PubMed Central

    Kraiselburd, Ivana; Alet, Analía I.; Tondo, María Laura; Petrocelli, Silvana; Daurelio, Lucas D.; Monzón, Jesica; Ruiz, Oscar A.; Losi, Aba; Orellano, Elena G.

    2012-01-01

    Recent studies have demonstrated that an appropriate light environment is required for the establishment of efficient vegetal resistance responses in several plant-pathogen interactions. The photoreceptors implicated in such responses are mainly those belonging to the phytochrome family. Data obtained from bacterial genome sequences revealed the presence of photosensory proteins of the BLUF (Blue Light sensing Using FAD), LOV (Light, Oxygen, Voltage) and phytochrome families with no known functions. Xanthomonas axonopodis pv. citri is a Gram-negative bacterium responsible for citrus canker. The in silico analysis of the X. axonopodis pv. citri genome sequence revealed the presence of a gene encoding a putative LOV photoreceptor, in addition to two genes encoding BLUF proteins. This suggests that blue light sensing could play a role in X. axonopodis pv. citri physiology. We obtained the recombinant Xac-LOV protein by expression in Escherichia coli and performed a spectroscopic analysis of the purified protein, which demonstrated that it has a canonical LOV photochemistry. We also constructed a mutant strain of X. axonopodis pv. citri lacking the LOV protein and found that the loss of this protein altered bacterial motility, exopolysaccharide production and biofilm formation. Moreover, we observed that the adhesion of the mutant strain to abiotic and biotic surfaces was significantly diminished compared to the wild-type. Finally, inoculation of orange (Citrus sinensis) leaves with the mutant strain of X. axonopodis pv. citri resulted in marked differences in the development of symptoms in plant tissues relative to the wild-type, suggesting a role for the Xac-LOV protein in the pathogenic process. Altogether, these results suggest the novel involvement of a photosensory system in the regulation of physiological attributes of a phytopathogenic bacterium. A functional blue light receptor in Xanthomonas spp. has been described for the first time, showing an important

  7. Responses of the Asian citrus psyllid to volatiles emitted by the flushing shoots of its rutaceous host plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaphorina citri Kuwayama (Hemiptera: Psyllidae) vectors Candidatus Liberibacter spp., the putative causal agents of Huanglongbing. D. citri reproduces and develops only on the flushing shoots of its rutaceous host plants. Here we examined whether D. citri is attracted to volatiles emitted by the ...

  8. Molecular genetic studies confirm that populations of Tamarixia radiata (Hymenoptera: Eulophidae) from Texas and Florida area a single species: natural enemies of the Asian citrus psylild

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tamarixia radiata (Waterston) (Hymenoptera: Eulophidae) is a natural enemy of the Asian citrus pysllid [Diaphorina citri Kuwayama (Hemiptera: Psyllidae]). D. citri is an important economic world-wide pest of citrus that recently invaded Texas, among several other states in the U. S. D. citri vecto...

  9. KatG, the Bifunctional Catalase of Xanthomonas citri subsp. citri, Responds to Hydrogen Peroxide and Contributes to Epiphytic Survival on Citrus Leaves.

    PubMed

    Tondo, María Laura; Delprato, María Laura; Kraiselburd, Ivana; Fernández Zenoff, María Verónica; Farías, María Eugenia; Orellano, Elena G

    2016-01-01

    Xanthomonas citri subsp. citri (Xcc) is the bacterium responsible for citrus canker. This bacterium is exposed to reactive oxygen species (ROS) at different points during its life cycle, including those normally produced by aerobic respiration or upon exposition to ultraviolet (UV) radiation. Moreover, ROS are key components of the host immune response. Among enzymatic ROS-detoxifying mechanisms, catalases eliminate H2O2, avoiding the potential damage caused by this specie. Xcc genome includes four catalase genes. In this work, we studied the physiological role of KatG, the only bifunctional catalase of Xcc, through the construction and characterization of a modified strain (XcckatG), carrying an insertional mutation in the katG gene. First, we evaluated the involvement of KatG in the bacterial adaptive response to H2O2. XcckatG cultures exhibited lower catalase activity than those of the wild-type strain, and this activity was not induced upon treatment with sub-lethal doses of H2O2. Moreover, the KatG-deficient mutant exhibited decreased tolerance to H2O2 toxicity compared to wild-type cells and accumulated high intracellular levels of peroxides upon exposure to sub-lethal concentrations of H2O2. To further study the role of KatG in Xcc physiology, we evaluated bacterial survival upon exposure to UV-A or UV-B radiation. In both conditions, XcckatG showed a high mortality in comparison to Xcc wild-type. Finally, we studied the development of bacterial biofilms. While structured biofilms were observed for the Xcc wild-type, the development of these structures was impaired for XcckatG. Based on these results, we demonstrated that KatG is responsible for Xcc adaptive response to H2O2 and a key component of the bacterial response to oxidative stress. Moreover, this enzyme plays an important role during Xcc epiphytic survival, being essential for biofilm formation and UV resistance. PMID:26990197

  10. The gpsX gene encoding a glycosyltransferase is important for polysaccharide production and required for full virulence in Xanthomonas citri subsp. citri

    PubMed Central

    2012-01-01

    Background The Gram-negative bacterium Xanthomonas citri subsp. citri (Xac) causes citrus canker, one of the most destructive diseases of citrus worldwide. In our previous work, a transposon mutant of Xac strain 306 with an insertion in the XAC3110 locus was isolated in a screening that aimed at identifying genes related to biofilm formation. The XAC3110 locus was named as bdp24 for biofilm-defective phenotype and the mutant was observed to be affected in extracellular polysaccharide (EPS) and lipopolysaccharide (LPS) biosynthesis and cell motility. In this study, we further characterized the bdp24 (XAC3110) gene (designated as gpsX) using genetic complementation assays and expanded the knowledge about the function of the gpsX gene in Xac pathogenesis by investigating the roles of gpsX in EPS and LPS production, cell motility, biofilm formation on host leaves, stress tolerance, growth in planta, and host virulence of the citrus canker bacterium. Results The gpsX gene encodes a putative glycosyltransferase, which is highly conserved in the sequenced strains of Xanthomonas. Mutation of gpsX resulted in a significant reduction of the amount of EPS and loss of two LPS bands visualized on sodium dodecylsulphate- polyacrylamide gels. Biofilm assays revealed that the gpsX mutation affected biofilm formation by Xac on abiotic and biotic surfaces. The gpsX mutant showed delayed bacterial growth and caused reduced development of disease symptoms in susceptible citrus leaves. The gpsX mutant was more sensitive than the wild-type strain to various stresses, including the H2O2 oxidative stress. The mutant also showed attenuated ability in cell motility but not in flagellar formation. Quantitative reverse transcription-PCR assays indicated that mutation of gpsX did not affect the expression of virulence genes such as pthA in Xac strain 306. The affected phenotypes of the gpsX mutant could be complemented to wild-type levels by the intact gpsX gene. Conclusions Taken together

  11. A survey of FLS2 genes from multiple citrus species identifies candidates for enhancing disease resistance to Xanthomonas citri ssp. citri.

    PubMed Central

    Shi, Qingchun; Febres, Vicente J; Jones, Jeffrey B; Moore, Gloria A

    2016-01-01

    Pathogen-associated molecular patterns (PAMPs)-triggered immunity (PTI) is an important component of plant innate immunity. In a previous study, we showed that the PAMP flg22 from Xanthomonas citri ssp. citri (Xflg22), the causal agent of citrus canker, induced PTI in citrus, which correlated with the observed levels of canker resistance. Here, we identified and sequenced two bacterial flagellin/flg22 receptors (FLS2-1 and FLS2-2) from ‘Duncan’ grapefruit (Citrus paradisi, CpFLS2-1 and CpFLS2-2) and ‘Sun Chu Sha’ mandarin (C. reticulata, CrFLS2-1 and CrFLS2-2). We were able to isolate only one FLS2 from ‘Nagami’ kumquat (Fortunella margarita, FmFLS2-1) and gene flanking sequences suggest a rearrangement event that resulted in the deletion of FLS2-2 from the genome. Phylogenetic analysis, gene structure and presence of critical amino acid domains all indicate we identified the true FLS2 genes in citrus. FLS2-2 was more transcriptionally responsive to Xflg22 than FLS2-1, with induced expression levels higher in canker-resistant citrus than in susceptible ones. Interestingly, ‘Nagami’ kumquat showed the highest FLS2-1 steady-state expression levels, although it was not induced by Xflg22. We selected FmFLS2-1, CrFLS2-2 and CpFLS2-2 to further evaluate their capacity to enhance bacterial resistance using Agrobacterium-mediated transient expression assays. Both FmFLS2-1 and CrFLS2-2, the two proteins from canker-resistant species, conferred stronger Xflg22 responses and reduced canker symptoms in leaves of the susceptible grapefruit genotype. These two citrus genes will be useful resources to enhance PTI and achieve resistance against canker and possibly other bacterial pathogens in susceptible citrus types. PMID:27222722

  12. KatG, the Bifunctional Catalase of Xanthomonas citri subsp. citri, Responds to Hydrogen Peroxide and Contributes to Epiphytic Survival on Citrus Leaves

    PubMed Central

    Tondo, María Laura; Delprato, María Laura; Kraiselburd, Ivana; Fernández Zenoff, María Verónica; Farías, María Eugenia; Orellano, Elena G.

    2016-01-01

    Xanthomonas citri subsp. citri (Xcc) is the bacterium responsible for citrus canker. This bacterium is exposed to reactive oxygen species (ROS) at different points during its life cycle, including those normally produced by aerobic respiration or upon exposition to ultraviolet (UV) radiation. Moreover, ROS are key components of the host immune response. Among enzymatic ROS-detoxifying mechanisms, catalases eliminate H2O2, avoiding the potential damage caused by this specie. Xcc genome includes four catalase genes. In this work, we studied the physiological role of KatG, the only bifunctional catalase of Xcc, through the construction and characterization of a modified strain (XcckatG), carrying an insertional mutation in the katG gene. First, we evaluated the involvement of KatG in the bacterial adaptive response to H2O2. XcckatG cultures exhibited lower catalase activity than those of the wild-type strain, and this activity was not induced upon treatment with sub-lethal doses of H2O2. Moreover, the KatG-deficient mutant exhibited decreased tolerance to H2O2 toxicity compared to wild-type cells and accumulated high intracellular levels of peroxides upon exposure to sub-lethal concentrations of H2O2. To further study the role of KatG in Xcc physiology, we evaluated bacterial survival upon exposure to UV-A or UV-B radiation. In both conditions, XcckatG showed a high mortality in comparison to Xcc wild-type. Finally, we studied the development of bacterial biofilms. While structured biofilms were observed for the Xcc wild-type, the development of these structures was impaired for XcckatG. Based on these results, we demonstrated that KatG is responsible for Xcc adaptive response to H2O2 and a key component of the bacterial response to oxidative stress. Moreover, this enzyme plays an important role during Xcc epiphytic survival, being essential for biofilm formation and UV resistance. PMID:26990197

  13. Can laboratory tholins mimic the chemistry producing Titan's aerosols? A review in light of ACP experimental results

    NASA Astrophysics Data System (ADS)

    Coll, P.; Navarro-González, R.; Szopa, C.; Poch, O.; Ramírez, S. I.; Coscia, D.; Raulin, F.; Cabane, M.; Buch, A.; Israël, G.

    2013-03-01

    The first results obtained by the ACP experiment onboard Huygens probe revealed that the main products obtained after thermolysis of Titan's collected aerosols, were ammonia (NH3) and hydrogen cyanide (HCN). Titan's aerosols, and their laboratory analogues named tholins, have been the subject of experimental or theoretical studies during the last four decades. These studies have been mainly devoted to understanding their origin and formation mechanisms, their physical, chemical and optical properties, and their role in the radiative equilibrium of the satellite. Before the arrival of the Cassini-Huygens mission, the dense layer of aerosols hid many aspects of the satellite's surface and precious information about its composition. If Titan's aerosols have been in the eye and mind of planetary scientists during such a long time, it is not surprising that a literature survey displays a good quantity of papers on aerosol analogues. With aerosol analogues we mean any material produced in a terrestrial laboratory under conditions that try to represent those of Titan's atmosphere. We present here a study aimed to understand the particularities of aerosol analogues synthesized in different laboratories around the world in order to determine some of their most representative chemical fingerprints and in some cases, to perform a direct comparison of the volatiles produced after a thermal treatment done in conditions similar to the ones used by the ACP experiment. From the information collected, we propose a broad classification of aerosol analogues highlighting the materials that can be more representative of Titan's aerosols in terms of their content of organic volatiles. We identify the laboratory analogs that best suit the ACP results; such identification is of prime importance to correctly predict the optical properties of Titan's aerosol and to accurately estimate their contribution in radiative equilibrium models and/or to assess their role in chemical reactions of

  14. Structural insights on two hypothetical secretion chaperones from Xanthomonas axonopodis pv. citri.

    PubMed

    Fattori, Juliana; Prando, Alessandra; Assis, Leandro H P; Aparicio, Ricardo; Tasic, Ljubica

    2011-06-01

    Several Gram-negative bacterial pathogens have developed type III secretion systems (T3SSs) to deliver virulence proteins directly into eukaryotic cells in a process essential for many diseases. The type III secretion processes require customized chaperones with high specificity for binding partners, thus providing the secretion to occur. Due to the very low sequence similarities among secretion chaperones, annotation and discrimination of a great majority of them is extremely difficult and a task with low scores even if genes are encountered that codify for small (<20 kDa) proteins with low pI and a tendency to dimerise. Concerning about this, herein, we present structural features on two hypothetical T3SSs chaperones belonging to plant pathogen Xanthomonas axonopodis pv. citri and suggest how low resolution models based on Small Angle X-ray Scattering patterns can provide new structural insights that could be very helpful in their analysis and posterior classification. PMID:21626158

  15. Glutamate transport and xanthan gum production in the plant pathogen Xanthomonas axonopodis pv. citri.

    PubMed

    Rojas, Robert; Nishidomi, Sabrina; Nepomuceno, Roberto; Oshiro, Elisa; de Cassia Café Ferreira, Rita

    2013-11-01

    L-glutamate plays a central role in nitrogen metabolism in all living organisms. In the genus Xanthomonas, the nitrogen nutrition is an important factor involved in the xanthan gum production, an important exopolysaccharide with various industrial and biotechnological applications. In this report, we demonstrate that the use of L-glutamate by the phytopathogen Xanthomonas axonopodis pv. citri as a nitrogen source in defined medium significantly increases the production of xanthan gum. This increase is dependent on the L-glutamate concentration. In addition, we have also characterized a glutamate transport system that is dependent on a proton gradient and on ATP and is modulated by amino acids that are structurally related to glutamate. This is the first biochemical characterization of an energy substrate transport system observed in a bacterial phytopathogen with a broad economic and industrial impact due to xanthan gum production. PMID:23719672

  16. Structural Analysis and Involvement in Plant Innate Immunity of Xanthomonas axonopodis pv. citri Lipopolysaccharide*

    PubMed Central

    Casabuono, Adriana; Petrocelli, Silvana; Ottado, Jorgelina; Orellano, Elena G.; Couto, Alicia S.

    2011-01-01

    Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, provoking defoliation and premature fruit drop with concomitant economical damage. In plant pathogenic bacteria, lipopolysaccharides are important virulence factors, and they are being increasingly recognized as major pathogen-associated molecular patterns for plants. In general, three domains are recognized in a lipopolysaccharide: the hydrophobic lipid A, the hydrophilic O-antigen polysaccharide, and the core oligosaccharide, connecting lipid A and O-antigen. In this work, we have determined the structure of purified lipopolysaccharides obtained from Xanthomonas axonopodis pv. citri wild type and a mutant of the O-antigen ABC transporter encoded by the wzt gene. High pH anion exchange chromatography and matrix-assisted laser desorption/ionization mass spectrum analysis were performed, enabling determination of the structure not only of the released oligosaccharides and lipid A moieties but also the intact lipopolysaccharides. The results demonstrate that Xac wild type and Xacwzt LPSs are composed mainly of a penta- or tetra-acylated diglucosamine backbone attached to either two pyrophosphorylethanolamine groups or to one pyrophosphorylethanolamine group and one phosphorylethanolamine group. The core region consists of a branched oligosaccharide formed by Kdo2Hex6GalA3Fuc3NAcRha4 and two phosphate groups. As expected, the presence of a rhamnose homo-oligosaccharide as O-antigen was determined only in the Xac wild type lipopolysaccharide. In addition, we have examined how lipopolysaccharides from Xac function in the pathogenesis process. We analyzed the response of the different lipopolysaccharides during the stomata aperture closure cycle, the callose deposition, the expression of defense-related genes, and reactive oxygen species production in citrus leaves, suggesting a functional role of the O-antigen from Xac lipopolysaccharides in the basal response. PMID:21596742

  17. Structural analysis and involvement in plant innate immunity of Xanthomonas axonopodis pv. citri lipopolysaccharide.

    PubMed

    Casabuono, Adriana; Petrocelli, Silvana; Ottado, Jorgelina; Orellano, Elena G; Couto, Alicia S

    2011-07-22

    Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, provoking defoliation and premature fruit drop with concomitant economical damage. In plant pathogenic bacteria, lipopolysaccharides are important virulence factors, and they are being increasingly recognized as major pathogen-associated molecular patterns for plants. In general, three domains are recognized in a lipopolysaccharide: the hydrophobic lipid A, the hydrophilic O-antigen polysaccharide, and the core oligosaccharide, connecting lipid A and O-antigen. In this work, we have determined the structure of purified lipopolysaccharides obtained from Xanthomonas axonopodis pv. citri wild type and a mutant of the O-antigen ABC transporter encoded by the wzt gene. High pH anion exchange chromatography and matrix-assisted laser desorption/ionization mass spectrum analysis were performed, enabling determination of the structure not only of the released oligosaccharides and lipid A moieties but also the intact lipopolysaccharides. The results demonstrate that Xac wild type and Xacwzt LPSs are composed mainly of a penta- or tetra-acylated diglucosamine backbone attached to either two pyrophosphorylethanolamine groups or to one pyrophosphorylethanolamine group and one phosphorylethanolamine group. The core region consists of a branched oligosaccharide formed by Kdo₂Hex₆GalA₃Fuc3NAcRha₄ and two phosphate groups. As expected, the presence of a rhamnose homo-oligosaccharide as O-antigen was determined only in the Xac wild type lipopolysaccharide. In addition, we have examined how lipopolysaccharides from Xac function in the pathogenesis process. We analyzed the response of the different lipopolysaccharides during the stomata aperture closure cycle, the callose deposition, the expression of defense-related genes, and reactive oxygen species production in citrus leaves, suggesting a functional role of the O-antigen from Xac lipopolysaccharides in the basal response. PMID:21596742

  18. Chemotactic signal transduction and phosphate metabolism as adaptive strategies during citrus canker induction by Xanthomonas citri.

    PubMed

    Moreira, Leandro Marcio; Facincani, Agda Paula; Ferreira, Cristiano Barbalho; Ferreira, Rafael Marine; Ferro, Maria Inês Tiraboshi; Gozzo, Fabio Cesar; de Oliveira, Julio Cezar Franco; Ferro, Jesus Aparecido; Soares, Márcia Regina

    2015-03-01

    The genome of Xanthomonas citri subsp. Citri strain 306 pathotype A (Xac) was completely sequenced more than 10 years; to date, few studies involving functional genomics Xac and its host compatible have been developed, specially related to adaptive events that allow the survival of Xac within the plant. Proteomic analysis of Xac showed that the processes of chemotactic signal transduction and phosphate metabolism are key adaptive strategies during the interaction of a pathogenic bacterium with its plant host. The results also indicate the importance of a group of proteins that may not be directly related to the classical virulence factors, but that are likely fundamental to the success of the initial stages of the infection, such as methyl-accepting chemotaxis protein (Mcp) and phosphate specific transport (Pst). Furthermore, the analysis of the mutant of the gene pstB which codifies to an ABC phosphate transporter subunit revealed a complete absence of citrus canker symptoms when inoculated in compatible hosts. We also conducted an in silico analysis which established the possible network of genes regulated by two-component systems PhoPQ and PhoBR (related to phosphate metabolism), and possible transcriptional factor binding site (TFBS) motifs of regulatory proteins PhoB and PhoP, detaching high degree of conservation of PhoB TFBS in 84 genes of Xac genome. This is the first time that chemotaxis signal transduction and phosphate metabolism were therefore indicated to be fundamental to the process of colonization of plant tissue during the induction of disease associated with Xanthomonas genus bacteria. PMID:25403594

  19. Biochemical and Structural Characterization of Germicidin Synthase: Analysis of a Type III Polyketide Synthase That Employs Acyl-ACP as a Starter Unit Donor

    SciTech Connect

    Chemler, Joseph A.; Buchholz, Tonia J.; Geders, Todd W.; Akey, David L.; Rath, Christopher M.; Chlipala, George E.; Smith, Janet L.; Sherman, David H.

    2012-08-10

    Germicidin synthase (Gcs) from Streptomyces coelicolor is a type III polyketide synthase (PKS) with broad substrate flexibility for acyl groups linked through a thioester bond to either coenzyme A (CoA) or acyl carrier protein (ACP). Germicidin synthesis was reconstituted in vitro by coupling Gcs with fatty acid biosynthesis. Since Gcs has broad substrate flexibility, we directly compared the kinetic properties of Gcs with both acyl-ACP and acyl-CoA. The catalytic efficiency of Gcs for acyl-ACP was 10-fold higher than for acyl-CoA, suggesting a strong preference toward carrier protein starter unit transfer. The 2.9 {angstrom} germicidin synthase crystal structure revealed canonical type III PKS architecture along with an unusual helical bundle of unknown function that appears to extend the dimerization interface. A pair of arginine residues adjacent to the active site affect catalytic activity but not ACP binding. This investigation provides new and surprising information about the interactions between type III PKSs and ACPs that will facilitate the construction of engineered systems for production of novel polyketides.

  20. Expression of Vibrio harveyi Acyl-ACP Synthetase Allows Efficient Entry of Exogenous Fatty Acids into the Escherichia coli Fatty Acid and Lipid A Synthetic Pathways

    PubMed Central

    Jiang, Yanfang; Morgan-Kiss, Rachael M.; Campbell, John W.; Chan, Chi Ho; Cronan, John E.

    2010-01-01

    Although the Escherichia coli fatty acid synthesis (FAS) pathway is the best studied type II fatty acid synthesis system, a major experimental limitation has been the inability to feed intermediates into the pathway in vivo because exogenously-supplied free fatty acids are not efficiently converted to the acyl-acyl carrier protein (ACP) thioesters required by the pathway. We report that expression of Vibrio harveyi acyl-ACP synthetase (AasS), a soluble cytosolic enzyme that ligates free fatty acids to ACP to form acyl-ACPs, allows exogenous fatty acids to enter the E. coli fatty acid synthesis pathway. The free fatty acids are incorporated intact and can be elongated or directly incorporated into complex lipids by acyltransferases specific for acyl-ACPs. Moreover, expression of AasS strains and supplementation with the appropriate fatty acid restored growth to E. coli mutant strains that lack essential fatty acid synthesis enzymes. Thus, this strategy provides a new tool for circumventing the loss of enzymes essential for FAS function. PMID:20028080

  1. Crystal structure of the FAD-containing ferredoxin-NADP+ reductase from the plant pathogen Xanthomonas axonopodis pv. citri.

    PubMed

    Tondo, María Laura; Hurtado-Guerrero, Ramon; Ceccarelli, Eduardo A; Medina, Milagros; Orellano, Elena G; Martínez-Júlvez, Marta

    2013-01-01

    We have solved the structure of ferredoxin-NADP(H) reductase, FPR, from the plant pathogen Xanthomonas axonopodis pv. citri, responsible for citrus canker, at a resolution of 1.5 Å. This structure reveals differences in the mobility of specific loops when compared to other FPRs, probably unrelated to the hydride transfer process, which contributes to explaining the structural and functional divergence between the subclass I FPRs. Interactions of the C-terminus of the enzyme with the phosphoadenosine of the cofactor FAD limit its mobility, thus affecting the entrance of nicotinamide into the active site. This structure opens the possibility of rationally designing drugs against the X. axonopodis pv. citri phytopathogen. PMID:23984418

  2. Discovery of an Allosteric Inhibitor Binding Site in 3-Oxo-acyl-ACP Reductase from Pseudomonas aeruginosa

    PubMed Central

    2013-01-01

    3-Oxo-acyl-acyl carrier protein (ACP) reductase (FabG) plays a key role in the bacterial fatty acid synthesis II system in pathogenic microorganisms, which has been recognized as a potential drug target. FabG catalyzes reduction of a 3-oxo-acyl-ACP intermediate during the elongation cycle of fatty acid biosynthesis. Here, we report gene deletion experiments that support the essentiality of this gene in P. aeruginosa and the identification of a number of small molecule FabG inhibitors with IC50 values in the nanomolar to low micromolar range and good physicochemical properties. Structural characterization of 16 FabG-inhibitor complexes by X-ray crystallography revealed that the compounds bind at a novel allosteric site located at the FabG subunit–subunit interface. Inhibitor binding relies primarily on hydrophobic interactions, but specific hydrogen bonds are also observed. Importantly, the binding cavity is formed upon complex formation and therefore would not be recognized by virtual screening approaches. The structure analysis further reveals that the inhibitors act by inducing conformational changes that propagate to the active site, resulting in a displacement of the catalytic triad and the inability to bind NADPH. PMID:24015914

  3. In silico analysis and modeling of ACP-MIP–PilQ chimeric antigen from Neisseria meningitidis serogroup B

    PubMed Central

    Gholami, Mehrdad; Salimi Chirani, Alireza; Moshiri, Mona; Sedighi, Mansour; Pournajaf, Abazar; Tohidfar, Masoud; Irajian, Gholamreza

    2015-01-01

    Background: Neisseria meningitidis, a life-threatening human pathogen with the potential to cause large epidemics, can be isolated from the nasopharynx of 5–15% of adults. The aim of the current study was to evaluate biophysical and biochemical properties and immunological aspects of chimeric acyl-carrier protein-macrophage infectivity potentiator protein-type IV pilus biogenesis protein antigen (ACP-MIP-PilQ) from N. meningitidis serogroup B strain. Methods: Biochemical properties and multiple alignments were predicted by appropriate web servers. Secondary molecular structures were predicted based on Chou and Fasman, Garnier-Osguthorpe-Robson, and Neural Network methods. Tertiary modeling elucidated conformational properties of the chimeric protein. Proteasome cleavage and transporter associated with antigen processing (TAP) binding sites, and T- and B-cell antigenic epitopes, were predicted using bioinformatic web servers. Results: Based on our in silico and immunoinformatics analyses, the ACP-MIP-PilQ protein (AMP) can induce high-level cross-strain bactericidal activity. In addition, several immune proteasomal cleavage sites were detected. The 22 epitopes associated with MHC class I and class II (DR) alleles were confirmed in the AMP. Thirty linear B-cell epitopes as antigenic regions were predicted from the full-length protein. Conclusion: All predicted properties of the AMP indicate it could be a good candidate for further immunological in vitro and in vivo studies. PMID:26989750

  4. Mutation in the xpsD gene of Xanthomonas axonopodis pv. citri affects cellulose degradation and virulence

    PubMed Central

    2010-01-01

    The Gram-negative bacterium Xanthomonas axonopodis pv. citri, the causal agent of citrus canker, is a major threat to the citrus industry worldwide. Although this is a leaf spot pathogen, it bears genes highly related to degradation of plant cell walls, which are typically found in plant pathogens that cause symptoms of tissue maceration. Little is known on Xac capacity to cause disease and hydrolyze cellulose. We investigated the contribution of various open reading frames on degradation of a cellulose compound by means of a global mutational assay to selectively screen for a defect in carboxymethyl cellulase (CMCase) secretion in X. axonopodis pv. citri. Screening on CMC agar revealed one mutant clone defective in extracellular glycanase activity, out of nearly 3,000 clones. The insertion was located in the xpsD gene, a component of the type II secretion system (T2SS) showing an influence in the ability of Xac to colonize tissues and hydrolyze cellulose. In summary, these data show for the first time, that X. axonopodis pv. citri is capable of hydrolyzing cellulose in a T2SS-dependent process. Furthermore, it was demonstrated that the ability to degrade cellulose contributes to the infection process as a whole. PMID:21637619

  5. Crystallization and preliminary X-ray diffraction analysis of the phosphate-binding protein PhoX from Xanthomonas citri.

    PubMed

    Pegos, Vanessa R; Medrano, Francisco Javier; Balan, Andrea

    2014-12-01

    Xanthomonas axonopodis pv. citri (X. citri) is an important bacterium that causes citrus canker disease in plants in Brazil and around the world, leading to significant economic losses. Determination of the physiology and mechanisms of pathogenesis of this bacterium is an important step in the development of strategies for its containment. Phosphate is an essential ion in all microrganisms owing its importance during the synthesis of macromolecules and in gene and protein regulation. Interestingly, X. citri has been identified to present two periplasmic binding proteins that have not been further characterized: PstS, from an ATP-binding cassette for high-affinity uptake and transport of phosphate, and PhoX, which is encoded by an operon that also contains a putative porin for the transport of phosphate. Here, the expression, purification and crystallization of the phosphate-binding protein PhoX and X-ray data collection at 3.0 Å resolution are described. Biochemical, biophysical and structural data for this protein will be helpful in the elucidation of its function in phosphate uptake and the physiology of the bacterium. PMID:25484207

  6. All Five Host-Range Variants of Xanthomonas citri Carry One pthA Homolog With 17.5 Repeats That Determines Pathogenicity on Citrus, but None Determine Host-Range Variation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker disease is caused by five groups of Xanthomonas citri strains that are distinguished primarily by host range: three from Asia (A, A*, and Aw) and two that form a phylogenetically distinct clade and originated in South America (B and C). Every X. citri strain carries multiple DNA fragme...

  7. Chemical control of the Asian citrus psyllid and of huanglongbing disease in citrus.

    PubMed

    Boina, Dhana Raj; Bloomquist, Jeffrey R

    2015-06-01

    By 2014, huanglongbing (HLB), the most destructive disease of citrus, and its insect vector, the Asian citrus psyllid (ACP), Diaphorina citri (Kuwayama), became established in all major citrus-growing regions of the world, including the United States, with the exception of California. At present, application of insecticides is the most widely followed option for reducing ACP populations, while application of antibiotics for suppressing HLB disease/symptoms is being practiced in some citrus-growing regions. Application of insecticides during the dormant winter season, along with cultivation of HLB-free seedlings and early detection and removal of symptomatic and asymptomatic trees, has been very effective in managing ACP. Area-wide management of ACP by application of insecticides at low volume in large areas of citrus cultivation has been shown to be effective in managing HLB and reducing management costs. As insecticide resistance is a major problem in sustainable management of ACP, rotation/alternation of insecticides with different chemistries and modes of action needs to be followed. Besides control of the insect vector, use of antibiotics has temporarily suppressed the symptoms of HLB in diseased trees. Recent efforts to discover and screen existing as well as new compounds for their antibiotic and antimicrobial activities have identified some promising molecules for HLB control. There is an urgent need to find a sustainable solution to the HLB menace through chemical control of ACP populations and within HLB-infected trees through the judicious use of labeled insecticides (existing and novel chemistries) and antibiotics in area-wide management programs with due consideration to the insecticide resistance problem. PMID:25491482

  8. Sampling Methods for Detection and Monitoring of the Asian Citrus Psyllid (Hemiptera: Psyllidae).

    PubMed

    Monzo, C; Arevalo, H A; Jones, M M; Vanaclocha, P; Croxton, S D; Qureshi, J A; Stansly, P A

    2015-06-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is a key pest of citrus due to its role as vector of citrus greening disease or "huanglongbing." ACP monitoring is considered an indispensable tool for management of vector and disease. In the present study, datasets collected between 2009 and 2013 from 245 citrus blocks were used to evaluate precision, sensitivity for detection, and efficiency of five sampling methods. The number of samples needed to reach a 0.25 standard error-mean ratio was estimated using Taylor's power law and used to compare precision among sampling methods. Comparison of detection sensitivity and time expenditure (cost) between stem-tap and other sampling methodologies conducted consecutively at the same location were also assessed. Stem-tap sampling was the most efficient sampling method when ACP densities were moderate to high and served as the basis for comparison with all other methods. Protocols that grouped trees near randomly selected locations across the block were more efficient than sampling trees at random across the block. Sweep net sampling was similar to stem-taps in number of captures per sampled unit, but less precise at any ACP density. Yellow sticky traps were 14 times more sensitive than stem-taps but much more time consuming and thus less efficient except at very low population densities. Visual sampling was efficient for detecting and monitoring ACP at low densities. Suction sampling was time consuming and taxing but the most sensitive of all methods for detection of sparse populations. This information can be used to optimize ACP monitoring efforts. PMID:26313984

  9. Campylobacter jejuni fatty acid synthase II: Structural and functional analysis of [beta]-hydroxyacyl-ACP dehydratase (FabZ)

    SciTech Connect

    Kirkpatrick, Andrew S.; Yokoyama, Takeshi; Choi, Kyoung-Jae; Yeo, Hye-Jeong

    2009-08-14

    Fatty acid biosynthesis is crucial for all living cells. In contrast to higher organisms, bacteria use a type II fatty acid synthase (FAS II) composed of a series of individual proteins, making FAS II enzymes excellent targets for antibiotics discovery. The {beta}-hydroxyacyl-ACP dehydratase (FabZ) catalyzes an essential step in the FAS II pathway. Here, we report the structure of Campylobacter jejuni FabZ (CjFabZ), showing a hexamer both in crystals and solution, with each protomer adopting the characteristic hot dog fold. Together with biochemical analysis of CjFabZ, we define the first functional FAS II enzyme from this pathogen, and provide a framework for investigation on roles of FAS II in C. jejuni virulence

  10. Cloning of Acyl-ACP Thioesterase FatA from Arachis hypogaea L. and Its Expression in Escherichia coli

    PubMed Central

    Chen, Gao; Peng, Zhen-ying; Shan, Lei; Xuan, Ning; Tang, Gui-ying; Zhang, Yan; Li, Lan; He, Qing-fang; Bi, Yu-ping

    2012-01-01

    In this study, a full-length cDNA of the acyl-ACP thioesterase, AhFatA, was cloned from developing seeds of Arachis hypogaea L. by 3′-RACE. Sequence analysis showed that the open reading frame encodes a peptide of 372 amino acids and has 50–70% identity with FatA from other plants. Real-time quantitative PCR analysis revealed that AhFatA was expressed in all tissues of A. hypogaea L., but most strongly in the immature seeds harvested at 60 days after pegging. Heterologous expression of AhFatA in Escherichia coli affected bacterial growth and changed the fatty acid profiles of the membrane lipid, resulting in directed accumulation towards palmitoleic acid and oleic acid. These results indicate that AhFatA is at least partially responsible for determining the high palmitoleic acid and oleic acid composition of E. coli. PMID:23093853

  11. X-ray structure of putative acyl-ACP desaturase DesA2 from Mycobacterium tuberculosis H37Rv

    SciTech Connect

    Dyer, David H.; Lyle, Karen S.; Rayment, Ivan; Fox, Brian G.

    2010-07-13

    Genome sequencing showed that two proteins in Mycobacterium tuberculosis H37Rv contain the metal binding motif (D/E)X{sub 2}HX{sub {approx}100}(D/E)X{sub 2}H characteristic of the soluble diiron enzyme superfamily. These putative acyl-ACP desaturase genes desA1 and desA2 were cloned from genomic DNA and expressed in Escherichia coli BL21(DE3). DesA1 was found to be insoluble, but in contrast, DesA2 was a soluble protein amenable to biophysical characterization. Here, we report the 2.0 {angstrom} resolution X-ray structure of DesA2 determined by multiple anomalous dispersion (MAD) phasing from a Se-met derivative and refinement against diffraction data obtained on the native protein. The X-ray structure shows that DesA2 is a homodimeric protein with a four-helix bundle core flanked by five additional helices that overlay with 192 structurally equivalent amino acids in the structure of stearoyl-ACP {Delta}9 desaturase from castor plant with an rms difference 1.42 {angstrom}. In the DesA2 crystals, one metal (likely Mn from the crystallization buffer) was bound in high occupancy at the B-site of the conserved metal binding motif, while the A-site was not occupied by a metal ion. Instead, the amino group of Lys-76 occupied this position. The relationships between DesA2 and known diiron enzymes are discussed.

  12. Crystallization and preliminary X-ray crystallographic analysis of enoyl-ACP reductase III (FabL) from Bacillus subtilis

    SciTech Connect

    Kim, Kook-Han; Park, Joon Kyu; Ha, Byung Hak; Moon, Jin Ho; Kim, Eunice EunKyeong

    2007-03-01

    Enoyl-ACP reductase III (FabL) from B. subtilis has been overexpressed, purified and crystallized. The crystal belongs to space group P622, with unit-cell parameters a = b = 139.56, c = 62.75 Å, α = β = 90, γ = 120°, and data were collected to 2.5 Å resolution using synchrotron radiation. Enoyl-[acyl-carrier protein] reductase (enoyl-ACP reductase; ENR) is a key enzyme in type II fatty-acid synthase that catalyzes the last step in each elongation cycle. It has been considered as an antibiotic target since it is an essential enzyme in bacteria. However, recent studies indicate that some pathogens have more than one ENR. Bacillus subtilis is reported to have two ENRs, namely BsFabI and BsFabL. While BsFabI is similar to other FabIs, BsFabL shows very little sequence similarity and is NADPH-dependent instead of NADH-dependent as in the case of FabI. In order to understand these differences on a structural basis, BsFabL has been cloned, expressed and and crystallized. The crystal belongs to space group P622, with unit-cell parameters a = b = 139.56, c = 62.75 Å, α = β = 90, γ = 120° and one molecule of FabL in the asymmetric unit. Data were collected using synchrotron radiation (beamline 4A at the Pohang Light Source, Korea). The crystal diffracted to 2.5 Å resolution.

  13. Effect of a mutagenized acyl-ACP thioesterase FATA allele from sunflower with improved activity in tobacco leaves and Arabidopsis seeds.

    PubMed

    Moreno-Pérez, Antonio Javier; Venegas-Calerón, Mónica; Vaistij, Fabián E; Salas, Joaquin J; Larson, Tony R; Garcés, Rafael; Graham, Ian A; Martínez-Force, Enrique

    2014-03-01

    The substrate specificity of the acyl-acyl carrier protein (ACP) thioesterases significantly determines the type of fatty acids that are exported from plastids. Thus, designing acyl-ACP thioesterases with different substrate specificities or kinetic properties would be of interest for plant lipid biotechnology to produce oils enriched in specialty fatty acids. In the present work, the FatA thioesterase from Helianthus annuus was used to test the impact of changes in the amino acids present in the binding pocket on substrate specificity and catalytic efficiency. Amongst all the mutated enzymes studied, Q215W was especially interesting as it had higher specificity towards saturated acyl-ACP substrates and higher catalytic efficiency compared to wild-type H. annuus FatA. Null, wild type and high-efficiency alleles were transiently expressed in tobacco leaves to check their effect on lipid biosynthesis. Expression of active FatA thioesterases altered the composition of leaf triacylglycerols but did not alter total lipid content. However, the expression of the wild type and the high-efficiency alleles in Arabidopsis thaliana transgenic seeds resulted in a strong reduction in oil content and an increase in total saturated fatty acid content. The role and influence of acyl-ACP thioesterases in plant metabolism and their possible applications in lipid biotechnology are discussed. PMID:24327259

  14. Expanding Access and Increasing Success in Postsecondary Education for Arizonans. The Arizona Commission for Postsecondary Education (ACPE) 2007-2008 Annual Report

    ERIC Educational Resources Information Center

    Arizona Commission for Postsecondary Education, 2008

    2008-01-01

    The work of the Arizona Commission for Postsecondary Education (ACPE) is guided by a 5-year strategic plan. The purpose of the plan is to provide focus for the activity of this small agency and its nine staff members in order to increase productivity and impact in the areas of its statutory authority. The mission and goals were accepted by …

  15. A comparison of surface roughness after micro abrasion of enamel with and without using CPP-ACP: An in vitro study

    PubMed Central

    Mathias, Jones; Kavitha, S; Mahalaxmi, S

    2009-01-01

    Aim: The aim of this study was to evaluate the surface roughness of enamel after micro abrasion with and without using remineralization agent, CPP-ACP (Casein Phosphopeptide-Amorphous Calcium Phosphate). Materials and Methods: Thirty freshly extracted anterior teeth were collected. The samples were randomly assigned to two study and one control group. Group A (n = 10) containing teeth in which only micro abrasion was done, Group B (n = 10) containing teeth in which CPP-ACP (G C Tooth Mousse) was applied after micro abrasion for a period of 30 days, once daily for three minutes and Group C (n = 10) in which no preparation was done and which acted as the control group. The samples were stored in artificial saliva and evaluated after 30 days, using surface profilometer. The results were tabulated and statistically analyzed. Results: According to the results of this study, a combination of the micro abrasion procedure and CPP-ACP application reduced the enamel surface roughness significantly, when compared to micro abrasion done alone. Conclusion: Application of CPP-ACP after micro abrasion procedure significantly reduces the enamel surface roughness thereby decreasing the risk of caries. PMID:20379436

  16. Expanding Access and Increasing Success in Postsecondary Education for Arizonans. The Arizona Commission for Postsecondary Education (ACPE) 2008-2009 Annual Report

    ERIC Educational Resources Information Center

    Arizona Commission for Postsecondary Education, 2009

    2009-01-01

    The work of the Arizona Commission for Postsecondary Education (ACPE) is guided by a 5-year strategic plan. The purpose of the plan is to provide focus for the activity of this small agency and its eight staff members in order to increase productivity and impact in the areas of its statutory authority. The mission and goals were accepted by…

  17. Expanding Access and Increasing Success in Postsecondary Education for Arizonans. The Arizona Commission for Postsecondary Education (ACPE) 2009-2010 Annual Report

    ERIC Educational Resources Information Center

    Arizona Commission for Postsecondary Education, 2010

    2010-01-01

    The work of the Arizona Commission for Postsecondary Education (ACPE) is guided by a strategic plan. The purpose of the plan is to provide focus for the activity of this small agency and its five staff members in order to increase productivity and impact in the areas of its statutory authority. The mission and goals were accepted by Commissioners…

  18. Expanding Access and Increasing Success in Postsecondary Education for Arizonans. Arizona Commission for Postsecondary Education (ACPE) Fiscal Year 2005-2006 Annual Report

    ERIC Educational Resources Information Center

    Arizona Commission for Postsecondary Education, 2006

    2006-01-01

    The work of the Arizona Commission for Postsecondary Education (ACPE) is guided by a 5-year strategic plan. The purpose of the plan is to provide focus for the activity of this small agency and its seven staff members in order to increase productivity and impact in the areas of its statutory authority. The mission and goals were accepted by…

  19. Enhanced free fatty acid production by codon-optimized Lactococcus lactis acyl-ACP thioesterase gene expression in Escherichia coli using crude glycerol.

    PubMed

    Lee, Sunhee; Park, Soohyun; Park, Chulhwan; Pack, Seung Pil; Lee, Jinwon

    2014-12-01

    Fatty acid production and composition are determined by the type of acyl-acyl carrier protein thioesterases (acyl-ACP TEs) expressed in Escherichia coli. Bacterial acyl-ACP TEs from Lactococcus lactis (SGJS47), Enterococcus faecalis (SGJS49), and Burkholderia cepacia (SGJS50) were codon-optimized and expressed in E. coli for enhanced fatty acid production. Samples were extracted at the lag, log, and stationary phases of cell growth, and gene expression levels of the codon optimized acy-ACP TEs as well as fatty acid production were monitored. At 24h after initiation of gene expression, the OPLlTE expression level and fatty acid production in SGJS47 increased up to 15.8-fold and 3.2-fold compared to the control and other recombinant strains, respectively. Additionally, in SGJS47, improvement in free fatty acid (FFA) composition, high-specificity production of short-chain fatty acids (C8, C10) and unsaturated fatty acids (C16:1) was achieved in crude glycerol medium condition. Compared with control strain, the percentage of FFAs (C8 and C10) was enhanced by approximately 16- to 21-fold, C16:1 FFA ratio increased approximately 18-fold. Observation of codon-optimized acyl-ACP TE genes expression level in E. coli may be useful for understanding mechanisms towards improving fatty acid production. Engineered strains have the potential to overproduce specific FFAs and thereby reduce the cost of fatty acid production by using industrially inexpensive carbon sources. PMID:25442943

  20. Morphological and metabolic changes in transgenic wheat with altered glycerol-3-phosphate acyltransferase or acyl-acyl carrier protein (ACP) thioesterase activities.

    PubMed

    Edlin, D A; Kille, P; Wilkinson, M D; Jones, H D; Harwood, J L

    2000-12-01

    We have transformed varieties of wheat with a Pisum sativum glycerol-3-phosphate acyltransferase gene, and also with an Arabidopsis thaliana acyl-ACP thioesterase gene. Morphological (growth, organelle development) and metabolic changes (fatty acid labelling of chloroplast and non-chloroplast lipids) have been observed in transgenics with altered gene expression for either enzyme. PMID:11171169

  1. Expanding Access and Increasing Success in Postsecondary Education for Arizonans. The Arizona Commission for Postsecondary Education (ACPE) 2006-2007 Annual Report

    ERIC Educational Resources Information Center

    Arizona Commission for Postsecondary Education, 2007

    2007-01-01

    The work of the Arizona Commission for Postsecondary Education (ACPE) is guided by a 5 year strategic plan. The purpose of the plan is to provide focus for the activity of this small agency and its eight staff members in order to increase productivity and impact in the areas of its statutory authority. The mission and goals were accepted by…

  2. The Xanthomonas axonopodis pv. citri flagellum is required for mature biofilm and canker development.

    PubMed

    Malamud, Florencia; Torres, Pablo S; Roeschlin, Roxana; Rigano, Luciano A; Enrique, Ramón; Bonomi, Hernán R; Castagnaro, Atilio P; Marano, María Rosa; Vojnov, Adrián A

    2011-03-01

    Xanthomonas axonopodis pv. citri (Xac) is the causative agent of citrus canker. This bacterium develops a characteristic biofilm on both biotic and abiotic surfaces. To evaluate the participation of the single flagellum of Xac in biofilm formation, mutants in the fliC (flagellin) and the flgE (hook) genes were generated. Swimming motility, assessed on 0.25 % agar plates, was markedly reduced in fliC and flgE mutants. However, the fliC and flgE mutants exhibited a flagellar-independent surface translocation on 0.5 % agar plates. Mutation of either the rpfF or the rpfC gene, which both encode proteins involved in cell-cell signalling mediated by diffusible signal factor (DSF), led to a reduction in both flagellar-dependent and flagellar-independent surface translocation, indicating a regulatory role for DSF in both types of motility. Confocal laser scanning microscopy of biofilms produced in static culture demonstrated that the flagellum is also involved in the formation of mushroom-shaped structures and water channels, and in the dispersion of biofilms. The presence of the flagellum was required for mature biofilm development on lemon leaf surfaces. The absence of flagellin produced a slight reduction in Xac pathogenicity and this reduction was more severe when the complete flagellum structure was absent. PMID:21109564

  3. Genomic insights into the evolutionary origin of Xanthomonas axonopodis pv. citri and its ecological relatives.

    PubMed

    Midha, Samriti; Patil, Prabhu B

    2014-10-01

    Xanthomonas axonopodis pv. citri (Xac) is the causal agent of citrus bacterial canker (CBC) and is a serious problem worldwide. Like CBC, several important diseases in other fruits, such as mango, pomegranate, and grape, are also caused by Xanthomonas pathovars that display remarkable specificity toward their hosts. While citrus and mango diseases were documented more than 100 years ago, the pomegranate and grape diseases have been known only since the 1950s and 1970s, respectively. Interestingly, diseases caused by all these pathovars were noted first in India. Our genome-based phylogenetic studies suggest that these diverse pathogens belong to a single species and these pathovars may be just a group of rapidly evolving strains. Furthermore, the recently reported pathovars, such as those infecting grape and pomegranate, form independent clonal lineages, while the citrus and mango pathovars that have been known for a long time form one clonal lineage. Such an understanding of their phylogenomic relationship has further allowed us to understand major and unique variations in the lineages that give rise to these pathovars. Whole-genome sequencing studies including ecological relatives from their putative country of origin has allowed us to understand the evolutionary history of Xac and other pathovars that infect fruits. PMID:25085494

  4. The GC/MS Analysis of Volatile Components Extracted by Different Methods from Exocarpium Citri Grandis.

    PubMed

    Xie, Zhisheng; Liu, Qundi; Liang, Zhikun; Zhao, Mingqian; Yu, Xiaoxue; Yang, Depo; Xu, Xinjun

    2013-01-01

    Volatile components from Exocarpium Citri Grandis (ECG) were, respectively, extracted by three methods, that is, steam distillation (SD), headspace solid-phase microextraction (HS-SPME), and solvent extraction (SE). A total of 81 compounds were identified by gas chromatography-mass spectrometry including 77 (SD), 56 (HS-SPME), and 48 (SE) compounds, respectively. Despite of the extraction method, terpenes (39.98~57.81%) were the main volatile components of ECG, mainly germacrene-D, limonene, 2,6,8,10,14-hexadecapentaene, 2,6,11,15-tetramethyl-, (E,E,E)-, and trans-caryophyllene. Comparison was made among the three methods in terms of extraction profile and property. SD relatively gave an entire profile of volatile in ECG by long-time extraction; SE enabled the analysis of low volatility and high molecular weight compounds but lost some volatiles components; HS-SPME generated satisfactory extraction efficiency and gave similar results to those of SD at analytical level when consuming less sample amount, shorter extraction time, and simpler procedure. Although SD and SE were treated as traditionally preparative extractive techniques for volatiles in both small batches and large scale, HS-SPME coupled with GC/MS could be useful and appropriative for the rapid extraction and qualitative analysis of volatile components from medicinal plants at analytical level. PMID:24349825

  5. Genomic Insights into the Evolutionary Origin of Xanthomonas axonopodis pv. citri and Its Ecological Relatives

    PubMed Central

    Midha, Samriti

    2014-01-01

    Xanthomonas axonopodis pv. citri (Xac) is the causal agent of citrus bacterial canker (CBC) and is a serious problem worldwide. Like CBC, several important diseases in other fruits, such as mango, pomegranate, and grape, are also caused by Xanthomonas pathovars that display remarkable specificity toward their hosts. While citrus and mango diseases were documented more than 100 years ago, the pomegranate and grape diseases have been known only since the 1950s and 1970s, respectively. Interestingly, diseases caused by all these pathovars were noted first in India. Our genome-based phylogenetic studies suggest that these diverse pathogens belong to a single species and these pathovars may be just a group of rapidly evolving strains. Furthermore, the recently reported pathovars, such as those infecting grape and pomegranate, form independent clonal lineages, while the citrus and mango pathovars that have been known for a long time form one clonal lineage. Such an understanding of their phylogenomic relationship has further allowed us to understand major and unique variations in the lineages that give rise to these pathovars. Whole-genome sequencing studies including ecological relatives from their putative country of origin has allowed us to understand the evolutionary history of Xac and other pathovars that infect fruits. PMID:25085494

  6. Comparative anaylsis of Asian citrus psyllid and potato psyllid antennae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The comparative investigation of the morphological basis for olfactory reception in the Asian citrus psyllid (Diaphorina citri) and the potato/tomato psyllid (Bactericera cockerelli (Hemiptera: Psyllidae) was performed using scanning electron microscopy to elucidate the antennal sensory arrays being...

  7. Novel delivery of the fungi Paecilomyces formosoroseus (Deuteromycotina: Hyphomycetes) for managing the Asian citrus psyllid (Psyllidae: Hemiptera)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method was developed to increase efficacy and reduce grower costs when using the biological control fungal agent Paecilomyces fumosoroseus blastospores (Deuteromycotina: Hyphomycetes) to infect adult Asian citrus psyllids, Diaphorina citri (Psyllidae: Hemiptera). We analyzed the efficacy of this A...

  8. Toxicity of pesticides to Tamarixia radiata, a parasitoid of the Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sixteen pesticides including two fungicides were evaluated for toxicity to adult Tamarixia radiata (Waterston) (Hymenoptera: Eulophidae), a parasitoid of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). Percentage mortality data were evaluated to generally assess IPM-com...

  9. Novel delivery of the fungi Paecilomyces formosoroseus (Deuteromycotina: Hyphomycetes) for managing the Asian citrus psyllid (Psyllidae: Hemiptera)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method was developed to increase efficacy and reduce grower costs when using the biological control fungal agent Paecilomyces fumosoroseus blastospores (Deuteromycotina: Hyphomycetes) to infect adult Asian citrus psyllids, Diaphorina citri (Psyllidae: Hemiptera). We analyzed the efficacy of this ‘...

  10. The PIP training programme: building of ACP experts capacities in crop protection and food safety to support local companies to comply with EU regulations on pesticides residues.

    PubMed

    Schiffers, B C; Schubert, A; Schiffers, C; Fontaine, S; Gumusboga, N; Werner, B; Webb, M; Lugros, H; Stinglhamber, G

    2006-01-01

    Regulatory requirements, and in particular phytosanitary quality standards change rapidly. As ACP producers/exporters race to become more competitive, to keep their market share and to satisfay their customers' commercial demands (e.g. EUREP-GAP certification), the need for competent staff who are aware of the company's quality objectives and trained to follow instructions is crucial. Mastering sanitary quality is only possible if matched with a programme to build the skills of companies' human resources. The Pesticide Initiative Programme (PIP), mindful of the importance of making operators autonomous and of training them to monitor EU food safety regulations and technology on their own, has successfully developed a training programme while building a quality network of local/ACP service providers. By building the capacities of ACP experts and then securing their services as trainers, PIP also guarantees companies' access to expertise and the sustainability of their efforts to comply with new EU regulations. The training strategy developed by PIP rests on two pilars: instructor training and collective training. Instructor training consists in reinforcing the technical knowledge of local experts (agronomists, hygienists, etc.) by providing them with active teaching methods. Once the ACP experts have gained enough technical knowledge of the key areas of crop protection--mainly pesticides management--and food safety, and have demonstrated their capacity to train the technical staff of local companies, the PIP has carried out a collective training programme in 2004, 2005 and 2006. To date, more than 130 consultants covering about 15 ACP countries have received instructor training, and more than 700 people have participated in collective and in-company training sessions. PMID:17390771

  11. Changes in free amino acids and polyamine levels in Satsuma leaves in response to Asian citrus psyllid infestation and water stress.

    PubMed

    Malik, Nasir S A; Perez, Jose L; Kunta, Madhurababu; Patt, Joseph M; Mangan, Robert L

    2014-12-01

    The effects of biotic and abiotic stresses on changes in amino acids and polyamine levels in Satsuma orange (Citrus unshiu; cultivar Owari) leaves were investigated. Asian citrus psyllids Diaphorina citri (Kuwayama) (ACP) infestation was used to induce biotic stress while a water deficit was imposed to induce abiotic stress. Potted trees were infested by placing 50 psyllids on 3 citrus leaves enclosed in nylon mesh bags for 5 d. A parallel set of plants were kept water stressed by maintaining the soil at 20% water holding capacity for 5 d. Levels of total free amino acids were higher in water stressed and ACP infested leaves. Polyamine putrescine increased in infested leaves but not in water stressed leaves. Proline was the most abundant amino acid and its levels significantly increased by both biotic and abiotic stresses. Proline levels in infested leaves were significantly higher than the water stressed leaves. Histidine, methionine, asparagine, arginine, serine, and leucine levels also increased significantly in infested leaves, but in water stressed leaves only leucine, methionine, and threonine increased. Levels of amino acids, such as tyrosine, isoleucine, phenylalanine, glutamic acid, and alanine, declined in infested leaves. Under water stress asparagine, phenylalanine, serine, and histidine also declined compared to controls. This indicates that while proteolysis occurred under both stresses, metabolic conversion of amino acids was different under the two stresses. In ACP infested leaves some amino acids may be used as feeding material and/or converted into secondary metabolites for defense. PMID:24178691

  12. Characterization of Bacteriophages Cp1 and Cp2, the Strain-Typing Agents for Xanthomonas axonopodis pv. citri

    PubMed Central

    Ahmad, Abdelmonim Ali; Ogawa, Megumi; Kawasaki, Takeru; Fujie, Makoto

    2014-01-01

    The strains of Xanthomonas axonopodis pv. citri, the causative agent of citrus canker, are historically classified based on bacteriophage (phage) sensitivity. Nearly all X. axonopodis pv. citri strains isolated from different regions in Japan are lysed by either phage Cp1 or Cp2; Cp1-sensitive (Cp1s) strains have been observed to be resistant to Cp2 (Cp2r) and vice versa. In this study, genomic and molecular characterization was performed for the typing agents Cp1 and Cp2. Morphologically, Cp1 belongs to the Siphoviridae. Genomic analysis revealed that its genome comprises 43,870-bp double-stranded DNA (dsDNA), with 10-bp 3′-extruding cohesive ends, and contains 48 open reading frames. The genomic organization was similar to that of Xanthomonas phage phiL7, but it lacked a group I intron in the DNA polymerase gene. Cp2 resembles morphologically Escherichia coli T7-like phages of Podoviridae. The 42,963-bp linear dsDNA genome of Cp2 contained terminal repeats. The Cp2 genomic sequence has 40 open reading frames, many of which did not show detectable homologs in the current databases. By proteomic analysis, a gene cluster encoding structural proteins corresponding to the class III module of T7-like phages was identified on the Cp2 genome. Therefore, Cp1 and Cp2 were found to belong to completely different virus groups. In addition, we found that Cp1 and Cp2 use different molecules on the host cell surface as phage receptors and that host selection of X. axonopodis pv. citri strains by Cp1 and Cp2 is not determined at the initial stage by binding to receptors. PMID:24123743

  13. Characterization of bacteriophages Cp1 and Cp2, the strain-typing agents for Xanthomonas axonopodis pv. citri.

    PubMed

    Ahmad, Abdelmonim Ali; Ogawa, Megumi; Kawasaki, Takeru; Fujie, Makoto; Yamada, Takashi

    2014-01-01

    The strains of Xanthomonas axonopodis pv. citri, the causative agent of citrus canker, are historically classified based on bacteriophage (phage) sensitivity. Nearly all X. axonopodis pv. citri strains isolated from different regions in Japan are lysed by either phage Cp1 or Cp2; Cp1-sensitive (Cp1(s)) strains have been observed to be resistant to Cp2 (Cp2(r)) and vice versa. In this study, genomic and molecular characterization was performed for the typing agents Cp1 and Cp2. Morphologically, Cp1 belongs to the Siphoviridae. Genomic analysis revealed that its genome comprises 43,870-bp double-stranded DNA (dsDNA), with 10-bp 3'-extruding cohesive ends, and contains 48 open reading frames. The genomic organization was similar to that of Xanthomonas phage phiL7, but it lacked a group I intron in the DNA polymerase gene. Cp2 resembles morphologically Escherichia coli T7-like phages of Podoviridae. The 42,963-bp linear dsDNA genome of Cp2 contained terminal repeats. The Cp2 genomic sequence has 40 open reading frames, many of which did not show detectable homologs in the current databases. By proteomic analysis, a gene cluster encoding structural proteins corresponding to the class III module of T7-like phages was identified on the Cp2 genome. Therefore, Cp1 and Cp2 were found to belong to completely different virus groups. In addition, we found that Cp1 and Cp2 use different molecules on the host cell surface as phage receptors and that host selection of X. axonopodis pv. citri strains by Cp1 and Cp2 is not determined at the initial stage by binding to receptors. PMID:24123743

  14. A pthA Homolog from Xanthomonas axonopodis pv. citri Responsible for Host-Specific Suppression of Virulence▿

    PubMed Central

    Shiotani, Hiroshi; Fujikawa, Takashi; Ishihara, Hiromichi; Tsuyumu, Sinji; Ozaki, Katsumi

    2007-01-01

    Strains of the plant-pathogenic bacterium Xanthomonas axonopodis pv. citri are differentiated into two groups with respect to aggressiveness (normal and weak) on Citrus grandis cultivars but not on other Citrus species such as Citrus sinensis. Random mutagenesis using the transposon Tn5 in X. axonopodis pv. citri strain KC21, which showed weak aggressiveness on a C. grandis cultivar, was used to isolate mutant KC21T46, which regained a normal level of aggressiveness on the cultivar. The gene inactivated by the transposon, hssB3.0, was shown to be responsible for the suppression of virulence on C. grandis. Sequence analysis revealed it to be a new member of the pthA homologs, which was almost identical in sequence to the other homologs except for the number of tandem repeats in the central region of the gene. hssB3.0 appears to be a chimera of other pthA homologs, pB3.1 and pB3.7, and could have been generated by recombination between these two genes. Importantly, in X. axonopodis pv. citri, hssB3.0 was found in all of the tested isolates belonging to the weakly aggressive group but not in the isolates of the normally aggressive group. Isolation of the virulence-deficient mutant KC21T14 from KC21, in which the pathogenicity gene pthA-KC21 was disrupted, showed that hssB3.0 induces a defense response on the host but partially interrupts canker development elicited by the pathogenicity gene in this bacterium. PMID:17293422

  15. Multiplexed lateral flow microarray assay for detection of citrus pathogens Xylella fastidiosa and Xanthomonas axonopodis pv citri

    DOEpatents

    Cary; R. Bruce; Stubben, Christopher J.

    2011-03-22

    The invention provides highly sensitive and specific assays for the major citrus pathogens Xylella fastidiosa and Xanthomonas axonopodis, including a field deployable multiplexed assay capable of rapidly assaying for both pathogens simultaneously. The assays are directed at particular gene targets derived from pathogenic strains that specifically cause the major citrus diseases of citrus variegated chlorosis (Xylella fastidiosa 9a5c) and citrus canker (Xanthomonas axonopodis pv citri). The citrus pathogen assays of the invention offer femtomole sensitivity, excellent linear dynamic range, and rapid and specific detection.

  16. Structural-functional characterization and physiological significance of ferredoxin-NADP reductase from Xanthomonas axonopodis pv. citri.

    PubMed

    Tondo, María Laura; Musumeci, Matías A; Delprato, María Laura; Ceccarelli, Eduardo A; Orellano, Elena G

    2011-01-01

    Xanthomonas axonopodis pv. citri is a phytopathogen bacterium that causes severe citrus canker disease. Similar to other phytopathogens, after infection by this bacterium, plants trigger a defense mechanism that produces reactive oxygen species. Ferredoxin-NADP(+) reductases (FNRs) are redox flavoenzymes that participate in several metabolic functions, including the response to reactive oxygen species. Xanthomonas axonopodis pv. citri has a gene (fpr) that encodes for a FNR (Xac-FNR) that belongs to the subclass I bacterial FNRs. The aim of this work was to search for the physiological role of this enzyme and to characterize its structural and functional properties. The functionality of Xac-FNR was tested by cross-complementation of a FNR knockout Escherichia coli strain, which exhibit high susceptibility to agents that produce an abnormal accumulation of (•)O(2)(-). Xac-FNR was able to substitute for the FNR in E. coli in its antioxidant role. The expression of fpr in X. axonopodis pv. citri was assessed using semiquantitative RT-PCR and Western blot analysis. A 2.2-fold induction was observed in the presence of the superoxide-generating agents methyl viologen and 2,3-dimethoxy-1,4-naphthoquinone. Structural and functional studies showed that Xac-FNR displayed different functional features from other subclass I bacterial FNRs. Our analyses suggest that these differences may be due to the unusual carboxy-terminal region. We propose a further classification of subclass I bacterial FNRs, which is useful to determine the nature of their ferredoxin redox partners. Using sequence analysis, we identified a ferredoxin (XAC1762) as a potential substrate of Xac-FNR. The purified ferredoxin protein displayed the typical broad UV-visible spectrum of [4Fe-4S] clusters and was able to function as substrate of Xac-FNR in the cytochrome c reductase activity. Our results suggest that Xac-FNR is involved in the oxidative stress response of Xanthomonas axonopodis pv. citri and

  17. Characterization of three linalool synthase genes from Citrus unshiu Marc. and analysis of linalool-mediated resistance against Xanthomonas citri subsp. citri and Penicilium italicum in citrus leaves and fruits.

    PubMed

    Shimada, Takehiko; Endo, Tomoko; Fujii, Hiroshi; Rodríguez, Ana; Peña, Leandro; Omura, Mitsuo

    2014-12-01

    Three cDNA clones from Satsuma mandarin (Citrus unshiu Marc.) were isolated and expressed in Escherichia coli. CuSTS3-1 and CuSTS3-2 encode linalool synthases and CuSTS4 encodes a nerolidol/linalool synthase. Transcripts of CuSTS3-1, CuSTS3-2 and CuSTS4 were abundant in young fruit at 60 days after flowering (DAF), flowers and leaves, respectively. Treatments with Xanthomonas citri subsp. citri (XCC), the causal agent of citrus canker and Penicillium italicum (PI), the cause of post-harvest fruit decay, and wounding up-regulated CuSTS3-1 in fruit and mainly CuSTS4 in leaves. Linalool, citral, geraniol and citronellol showed strong antibacterial and antifungal activities against XCC and PI in vitro, while most other mono-and sesquiterpenes, including limonene and gamma-terpinene, did not. Linalool, used at levels similar to those present in resistant Ponkan mandarin (Citrus reticulata Blanco) leaves, was able to inhibit growth of XCC in vitro. Compared to other five citrus types, linalool accumulated at extraordinarily high levels in Ponkan mandarin leaves and was released at high amounts from their leaves, while it was hardly detectable in the most susceptible species, indicating that linalool biosynthesis and accumulation might be involved in plant defense against bacterial and fungal pathogens and be associated with field resistance to citrus canker. PMID:25443842

  18. Amplification of DNA of Xanthomonas axonopodis pv. citri from historic citrus canker herbarium specimens.

    PubMed

    Li, Wenbin; Brlansky, Ronald H; Hartung, John S

    2006-05-01

    Herbaria are important resources for the study of the origins and dispersal of plant pathogens, particularly bacterial plant pathogens that incite local lesions in which large numbers of pathogen genomes are concentrated. Xanthomonas axonopodis pv. citri (Xac), the causal agent of citrus bacterial canker disease, is a notable example of such a pathogen. The appearance of novel strains of the pathogen in Florida and elsewhere make it increasingly important to understand the relationships among strains of this pathogen. USDA-ARS at Beltsville, Maryland maintains approximately 700 herbarium specimens with citrus canker disease lesions up to 90 years old, originally collected from all over the world, and so is an important resource for phytogeographic studies of this bacterium. Unfortunately, DNA in herbarium specimens is degraded and may contain high levels of inhibitors of PCR. In this study, we compared a total of 23 DNA isolation techniques in combination with 31 novel primer pairs in order to develop an efficient protocol for the analysis of Xac DNA in herbarium specimens. We identified the most reliable extraction method, identified in terms of successful amplification by our panel of 31 primer pairs. We also identified the most robust primer pairs, identified as successful in the largest number of extracts prepared by different methods. We amplified Xac genomic sequences up to 542 bp long from herbarium samples up to 89 years old. Primers varied in effectiveness, with some primer pairs amplifying Xac DNA from a 1/10,000 dilution of extract from a single lesion from a citrus canker herbarium specimen. Our methodology will be useful to identify pathogens and perform molecular analyses of bacterial and possibly fungal genomes from herbarium specimens. PMID:16099061

  19. Contribution of a harpin protein from Xanthomonas axonopodis pv. citri to pathogen virulence.

    PubMed

    Sgro, Germán G; Ficarra, Florencia A; Dunger, Germán; Scarpeci, Telma E; Valle, Estela M; Cortadi, Adriana; Orellano, Elena G; Gottig, Natalia; Ottado, Jorgelina

    2012-12-01

    Xanthomonas axonopodis pv. citri (Xac), the bacterium that causes citrus canker, contains a gene in the hrp [for hypersensitive response (HR) and pathogenicity] cluster that encodes a harpin protein called Hpa1. Hpa1 produced HR in the nonhost plants tobacco, pepper and Arabidopsis, whereas, in the host plant citrus, it elicited a weak defence response with no visible phenotype. Co-infiltrations of Xac with or without the recombinant Hpa1 protein in citrus leaves produced a larger number of cankers in the presence of the protein. To characterize the effect of Hpa1 during the disease, an XacΔhpa1 mutant was constructed, and infiltration of this mutant caused a smaller number of cankers. In addition, the lack of Hpa1 hindered bacterial aggregation both in solution and in planta. Analysis of citrus leaves infiltrated with Hpa1 revealed alterations in mesophyll morphology caused by the presence of cavitations and crystal idioblasts, suggesting the binding of the harpin to plant membranes and the elicitation of signalling cascades. Overall, these results suggest that, even though Hpa1 elicits the defence response in nonhost plants and, to a lesser extent, in host plants, its main roles in citrus canker are to alter leaf mesophyll structure and to aggregate bacterial cells, and thus increase virulence and pathogen fitness. We expressed the N-terminal and C-terminal regions and found that, although both regions elicited HR in nonhost plants, only the N-terminal region showed increased virulence and bacterial aggregation, supporting the role of this region of the protein as the main active domain. PMID:22788999

  20. Foraging on and consumption of two species of papaya pest mites, Tetranychus kanzawai and Panonychus citri (Acari: tetranychidae) by Mallada basalis (Neuroptera: Chrysopidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tetranychus kanzawai Kishida and Panonychus citri (McGregor) are two major acarine pests of the principal papaya variety in Taiwan, and they often co-occur in the same papaya screenhouses. This study measured prey acceptability, foraging schedule, short-term consumption rate, and handling time of la...

  1. The solution structure of the outer membrane lipoprotein OmlA from Xanthomonas axonopodis pv. citri reveals a protein fold implicated in protein-protein interaction.

    PubMed

    Vanini, Marina Marques Teixeira; Spisni, Alberto; Sforça, Maurício Luis; Pertinhez, Thelma Aguiar; Benedetti, Celso Eduardo

    2008-06-01

    The outer membrane lipoprotein A (OmlA) belongs to a family of bacterial small lipoproteins widely distributed across the beta and gamma proteobacteria. Although the role of numerous bacterial lipoproteins is known, the biological function of OmlA remains elusive. We found that in the citrus canker pathogen, Xanthomonas axonopodis pv. citri (X. citri), OmlA is coregulated with the ferric uptake regulator (Fur) and their expression is enhanced when X. citri is grown on citrus leaves, suggesting that these proteins are involved in plant-pathogen interaction. To gain insights into the function of OmlA, its conformational and dynamic features were determined by nuclear magnetic resonance. The protein has highly flexible N- and C- termini and a structurally well defined core composed of three beta-strands and two small alpha-helices, which pack against each other forming a two-layer alpha/beta scaffold. This protein fold resembles the domains of the beta-lactamase inhibitory protein BLIP, involved in protein-protein binding. In conclusion, the structure of OmlA does suggest that this protein may be implicated in protein-protein interactions required during X. citri infection. PMID:18186471

  2. Functional analysis of a chitinase gene during the larval-nymph transition in Panonychus citri by RNA interference.

    PubMed

    Xia, Wen-Kai; Shen, Xiao-Min; Ding, Tian-Bo; Niu, Jin-Zhi; Zhong, Rui; Liao, Chong-Yu; Feng, Ying-Cai; Dou, Wei; Wang, Jin-Jun

    2016-09-01

    Chitinases are hydrolytic enzymes that are required for chitin degradation and reconstruction in arthropods. In this study, we report a cDNA sequence encoding a putative chitinase (PcCht1) from the citrus red mite, Panonychus citri. The PcCht1 (564 aa) possessed a signal peptide, a conserver domain, and a chitin-binding domain. Structural and phylogenetic analyses found that PcCht1 had high sequence similarity to chitinases in Tetranychus urticae. Real-time quantitative PCR analyses showed that the transcript levels of PcCht1 peaked periodically in larval and nymph stages. Moreover, significant increase of PcCht1 transcript level in the larvae was observed upon the exposure of diflubenzuron. In contrast, exposures of the larvae to diflubenzuron resulted in the decreased chitin content. Furthermore, through a feeding-based RNA interference approach, we were able to reduce the PcCht1 transcript level by 59.7 % in the larvae, and consequently the treated larvae showed a very low molting rate compared with the control. Our results expanded the understanding of the important role of PcCht1 in the growth and development of P. citri. PMID:27388447

  3. Crystallization, data collection and phasing of the molybdate-binding protein of the phytopathogen Xanthomonas axonopodis pv. citri

    SciTech Connect

    Santacruz, C. P.; Balan, A.; Ferreira, L. C. S.; Barbosa, J. A. R. G.

    2006-03-01

    The molybdate-binding protein (ModA) from X. axonopodis pv. citri was crystallized with sodium molybdate in the presence of PEG or sulfate. The crystal diffracted to a maximum resolution of 1.7 Å and belongs to the orthorhombic space group C222{sub 1,} with unit-cell parameters a = 68.15, b = 172.14, c = 112.04 Å. Xanthomonas axonopodis pv. citri ModA protein is the ABC periplasmic binding component responsible for the capture of molybdate. The protein was crystallized with sodium molybdate using the hanging-drop vapour-diffusion method in the presence of PEG or sulfate. X-ray diffraction data were collected to a maximum resolution of 1.7 Å using synchrotron radiation. The crystal belongs to the orthorhombic space group C222{sub 1}, with unit-cell parameters a = 68.15, b = 172.14, c = 112.04 Å. The crystal structure was solved by molecular-replacement methods and structure refinement is in progress.

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

    PubMed

    Vyas, Meenal; Fisher, Tonja W; He, Ruifeng; Nelson, William; Yin, Guohua; Cicero, Joseph M; Willer, Mark; Kim, Ryan; Kramer, Robin; May, Greg A; Crow, John A; Soderlund, Carol A; Gang, David R; Brown, Judith K

    2015-01-01

    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 transmission. PMID

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

    PubMed Central

    He, Ruifeng; Nelson, William; Yin, Guohua; Cicero, Joseph M.; Willer, Mark; Kim, Ryan; Kramer, Robin; May, Greg A.; Crow, John A.; Soderlund, Carol A.; Gang, David R.; Brown, Judith K.

    2015-01-01

    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 transmission. PMID

  6. Transcriptional activation of Brassica napus β-ketoacyl-ACP synthase II with an engineered zinc finger protein transcription factor.

    PubMed

    Gupta, Manju; DeKelver, Russell C; Palta, Asha; Clifford, Carla; Gopalan, Sunita; Miller, Jeffrey C; Novak, Stephen; Desloover, Daniel; Gachotte, Daniel; Connell, James; Flook, Josh; Patterson, Thomas; Robbins, Kelly; Rebar, Edward J; Gregory, Philip D; Urnov, Fyodor D; Petolino, Joseph F

    2012-09-01

    Targeted gene regulation via designed transcription factors has great potential for precise phenotypic modification and acceleration of novel crop trait development. Canola seed oil composition is dictated largely by the expression of genes encoding enzymes in the fatty acid biosynthetic pathway. In the present study, zinc finger proteins (ZFPs) were designed to bind DNA sequences common to two canola β-ketoacyl-ACP Synthase II (KASII) genes downstream of their transcription start site. Transcriptional activators (ZFP-TFs) were constructed by fusing these ZFP DNA-binding domains to the VP16 transcriptional activation domain. Following transformation using Agrobacterium, transgenic events expressing ZFP-TFs were generated and shown to have elevated KASII transcript levels in the leaves of transgenic T(0) plants when compared to 'selectable marker only' controls as well as of T(1) progeny plants when compared to null segregants. In addition, leaves of ZFP-TF-expressing T(1) plants contained statistically significant decreases in palmitic acid (consistent with increased KASII activity) and increased total C18. Similarly, T(2) seed displayed statistically significant decreases in palmitic acid, increased total C18 and reduced total saturated fatty acid contents. These results demonstrate that designed ZFP-TFs can be used to regulate the expression of endogenous genes to elicit specific phenotypic modifications of agronomically relevant traits in a crop species. PMID:22520333

  7. Modification of Triclosan Scaffold in Search of Improved Inhibitors for Enoyl-Acyl Carrier Protein (ACP) Reductase in Toxoplasma gondii

    PubMed Central

    Stec, Jozef; Fomovska, Alina; Afanador, Gustavo A.; Muench, Stephen P.; Zhou, Ying; Lai, Bo-Shiun; Bissati, Kamal El; Hickman, Mark R.; Lee, Patty J.; Leed, Susan E.; Auschwitz, Jennifer M.; Sommervile, Caroline; Woods, Stuart; Roberts, Craig W.; Rice, David; Prigge, Sean T.; McLeod, Rima; Kozikowski, Alan P.

    2013-01-01

    Through our focused effort to discover new and effective agents against toxoplasmosis, a structure-based drug design approach was utilized to develop a series of potent inhibitors of the enoyl-acyl carrier protein (ACP) reductase (ENR) enzyme in Toxoplasma gondii (TgENR). Modifications to positions 5 and 4′ of the well-known ENR inhibitor triclosan afforded a series of 29 new analogs. Among the resulting compounds, many showed high potency and improved physicochemical properties in comparison with the lead. The most potent compounds 16a and 16c have IC50 values of 250 nM against Toxoplasma gondii tachyzoites without apparent toxicity to the host cells. Their IC50 values against the recombinant TgENR were 43 and 26 nM, respectively. Additionally, 11 other analogs in this series had IC50 values ranging from 17 to 130 nM in the enzyme-based assay. With respect to their excellent in vitro activity as well as improved drug-like properties, the lead compounds 16a and 16c are deemed to be an excellent starting point for the development of new medicines to effectively treat Toxoplasma gondii infections. PMID:23776166

  8. 3-Oxoacyl-ACP Reductase from Schistosoma japonicum: Integrated In Silico-In Vitro Strategy for Discovering Antischistosomal Lead Compounds

    PubMed Central

    Liu, Jian; Dyer, Dave; Wang, Jipeng; Wang, Shuqi; Du, Xiaofeng; Xu, Bin; Zhang, Haobing; Wang, Xiaoning; Hu, Wei

    2013-01-01

    Background Schistosomiasis is a disease caused by parasitic worms and more than 200 million people are infected worldwide. The emergence of resistance to the most commonly used drug, praziquantel (PZQ), makes the development of novel drugs an urgent task. 3-oxoacyl-ACP reductase (OAR), a key enzyme involved in the fatty acid synthesis pathway, has been identified as a potential drug target against many pathogenic organisms. However, no research on Schistosoma japonicum OAR (SjOAR) has been reported. The characterization of the SjOAR protein will provide new strategies for screening antischistosomal drugs that target SjOAR. Methodology/Principal Findings After cloning the SjOAR gene, recombinant SjOAR protein was purified and assayed for enzymatic activity. The tertiary structure of SjOAR was obtained by homology modeling and 27 inhibitor candidates were identified from 14,400 compounds through molecular docking based on the structure. All of these compounds were confirmed to be able to bind to the SjOAR protein by BIAcore analysis. Two compounds exhibited strong antischistosomal activity and inhibitory effects on the enzymatic activity of SjOAR. In contrast, these two compounds showed relatively low toxicity towards host cells. Conclusions/Significance The work presented here shows the feasibility of isolation of new antischistosomal compounds using a combination of virtual screening and experimental validation. Based on this strategy, we successfully identified 2 compounds that target SjOAR with strong antischistosomal activity but relatively low cytotoxicity to host cells. PMID:23762275

  9. A [32P]-NAD+-based method to identify and quantitate long residence time enoyl-ACP reductase inhibitors

    PubMed Central

    Yu, Weixuan; Neckles, Carla; Chang, Andrew; Bommineni, Gopal Reddy; Spagnuolo, Lauren; Zhang, Zhuo; Liu, Nina; Lai, Christina; Truglio, James; Tonge, Peter J.

    2015-01-01

    The classical methods for quantifying drug-target residence time (tR) use loss or regain of enzyme activity in progress curve kinetic assays. However, such methods become imprecise at very long residence times, mitigating the use of alternative strategies. Using the NAD(P)H-dependent FabI enoyl-ACP reductase as a model system, we developed a Penefsky column-based method for direct measurement of tR, where the off-rate of the drug was determined with radiolabeled [adenylate-32P] NAD(P+) cofactor. Twenty-three FabI inhibitors were analyzed and a mathematical model was used to estimate limits to the tR values of each inhibitor based on percent drug-target complex recovery following gel filtration. In general, this method showed good agreement with the classical steady state kinetic methods for compounds with tR values of 10-100 min. In addition, we were able to identify seven long tR inhibitors (100-1500 min) and to accurately determine their tR values. The method was then used to measure tR as a function of temperature, an analysis not previously possible using the standard kinetic approach due to decreased NAD(P)H stability at elevated temperatures. In general, a 4-fold difference in tR was observed when the temperature was increased from 25 °C to 37 °C . PMID:25684450

  10. A preliminary study of enamel remineralization by dentifrices based on Recalden (CPP-ACP) and Novamin (calcium-sodium-phosphosilicate).

    PubMed

    Gjorgievska, Elizabeta S; Nicholson, John W

    2010-01-01

    The purpose of this study was to investigate the enamel remineralization potential of two toothpastes, one of which was based on Recaldent (CPP- ACP) and the other on NovaMin (Calcium-sodium-phosphosilicate). Human permanent molar teeth were subjected to three consecutive demineralization cycles. These cycles were followed by remineralization of the experimental groups by toothpastes containing Recalden and NovaMin respectively. The samples were analyzed by Scanning Electron Microscope, (SEM) and energy-dispersive X-ray spectroscopy analysis (EDX). Extensive demineralization was noted in the control group (without remineralization) while the groups treated with the dentifices demonstrated various degrees of remineralization, as shown by formation of different types of deposits on the enamel surface. The EDX analysis showed increased amounts of Ca, P Si and Zn in the enamel of the experimental groups, compared to the control one. Toothpastes containing Recalden and especially NovaMin have the potential to remineralize enamel, a property which might be important in finding a substitute to pit and fissure sealing. PMID:21638965

  11. Foraging on and consumption of two species of papaya pest mites, Tetranychus kanzawai and Panonychus citri (Acari: Tetranychidae), by Mallada basalis (Neuroptera: Chrysopidae).

    PubMed

    Cheng, Ling Lan; Nechols, James R; Margolies, David C; Campbell, James F; Yang, Ping Shih; Chen, Chien Chung; Lu, Chiu Tung

    2009-06-01

    Tetranychus kanzawai Kishida and Panonychus citri (McGregor) are two major acarine pests of the principal papaya variety in Taiwan, and they often co-occur in the same papaya screenhouses. This study measured prey acceptability, foraging schedule, short-term consumption rate, and handling time of larvae of a domesticated line of the green lacewing, Mallada basalis (Walker), in no-choice tests with different life stages of these two mite pests. After a period of prey deprivation, all three larval instars of M. basalis exhibited a high rate of acceptance of all life stages of both T. kanzawai and P. citri. In 2-h trials, second- and third-instar predators foraged actively most of the time, whereas first instars spent approximately 40% of the time at rest. Consumption increased and prey handling time decreased as predator life stage advanced and prey stage decreased. Third-instar lacewings consumed an average of 311.4 T. kanzawai eggs (handling time: 6.7 s/egg) and 68.2 adults (handling time: 58.8 s/adult), whereas first instars consumed 19.6 eggs (handling time: 23.6 s/egg) and 4.0 adults (handling time: 633.4 s/adult). M. basalis generally consumed more P. citri than T. kanzawai. Except for prey eggs, handling times of T. kanzawai were generally longer than those of P. citri by all M. basalis instars. Handling times were shorter, and consumption were greater, at the higher P. citri density than at the lower one, whereas there were generally no significant differences in prey acceptability and foraging time between those two densities. This study suggests that M. basalis larvae may have high potential for augmentative biological control of mites on papayas. PMID:19508780

  12. Cloning and characterization of cDNAs encoding for long-chain saturated acyl-ACP thioesterases from the developing seeds of Brassica juncea.

    PubMed

    Jha, Saheli Sinha; Jha, Jyoti K; Chattopadhyaya, Banani; Basu, Asitava; Sen, Soumitra K; Maiti, Mrinal K

    2010-06-01

    Four types of cDNAs corresponding to the fatty acyl-acyl carrier protein (ACP) thioesterase (Fat) enzyme were isolated from the developing seeds of Brassica juncea, a widely cultivated species amongst the oil-seed crops. The mature polypeptides deduced from the cDNAs showed sequence identity with the FatB class of plant thioesterases. Southern hybridization revealed the presence of at least four copies of BjFatB gene in the genome of this amphidiploid species. Western blot and RT-PCR analyses showed that the BjFatB class thioesterase is expressed poorly in flowers and leaves, but significantly in seeds at the mid-maturation stage. The enzymatic activities of different BjFatB isoforms were established upon heterologous expression of the four BjFatB CDSs in Escherichia coli K27fadD88, a mutant strain of fatty acid beta-oxidation pathway. The substrate specificity of each BjFatB isoform was determined in vivo by fatty acid profile analyses of the culture supernatant and membrane lipid of the recombinant K27fadD88 and E. coli DH10B (fadD(+)) clones, respectively. The BjFatB1 and BjFatB3 were predominantly active on C18:0-ACP substrate, whereas BjFatB2 and BjFatB4 were specific towards C18:0-ACP as well as C16:0-ACP. These novel FatB genes may find potential application in metabolic engineering of crop plants through their over-expression in seed tissues to generate stearate-rich vegetable fats/oils of commercial importance. PMID:20356753

  13. Cryopreservation of collared peccaries (Tayassu tajacu) semen using a powdered coconut water (ACP-116c) based extender plus various concentrations of egg yolk and glycerol.

    PubMed

    Silva, M A; Peixoto, G C X; Lima, G L; Bezerra, J A B; Campos, L B; Paiva, A L C; Paula, V V; Silva, A R

    2012-08-01

    The objective was to determine the effectiveness of a powdered coconut water-based extender (ACP-116c), plus various concentrations of egg-yolk and glycerol, as an alternative for cryopreservation of collared peccary semen. Twelve ejaculates were obtained from captive adult males by electroejaculation, and evaluated for sperm motility, kinetic rating, viability, morphology, and functional membrane integrity. The ejaculates were apportioned into aliquots that were diluted in Tris plus 10% egg yolk and 3% glycerol, or in ACP-116c plus 10 or 20% egg yolk and 1.5 or 3% glycerol. Samples were frozen in liquid nitrogen and, after 1 mo, thawed at 37 °C for 1 min. After thawing, samples were evaluated as reported for fresh semen, and also for sperm membrane integrity (fluorescent probes) and kinematic parameters (computerized analysis). Results were presented as means ± SEM. Freezing and thawing decreased sperm characteristics relative to fresh semen. Overall, ACP-116c plus 20% egg yolk and 3% glycerol provided better (P < 0.05) sperm motility and kinetic rating (48 ± 6.1% and 2.8 ± 0.2, respectively) after thawing than Tris extender (30.4 ± 5.7% and 2.4 ± 0.2). However, there were no differences (P > 0.05) among treatments with regard to the other sperm characteristics. Based on computerized motion analysis, total (26.5 ± 5.9%) and progressive (8.1 ± 2.2%) motility were best preserved (P < 0.05) with the above-mentioned treatment. In conclusion, a coconut water-based extender, ACP-116c, plus 20% egg yolk and 3% glycerol, was effective for cryopreservation of semen from collared peccaries. PMID:22538005

  14. Radiolabelling and positron emission tomography of PT70, a time-dependent inhibitor of InhA, the Mycobacterium tuberculosis enoyl-ACP reductase

    DOE PAGESBeta

    Wang, Hui; Liu, Li; Lu, Yang; Pan, Pan; Hooker, Jacob M.; Fowler, Joanna S.; Tonge, Peter J.

    2015-07-14

    PT70 is a diaryl ether inhibitor of InhA, the enoyl-ACP reductase in the Mycobacterium tuberculosis fatty acid biosynthesis pathway. It has a residence time of 24 min on the target, and also shows antibacterial activity in a mouse model of tuberculosis infection. Due to the interest in studying target tissue pharmacokinetics of PT70, we developed a method to radiolabel PT70 with carbon-11 and have studied its pharmacokinetics in mice and baboons using positron emission tomography.

  15. Mutations in a delta9-Stearoyl-ACP-Desaturase Gene Are Associated with Enhanced Stearic Acid Levels in Soybean Seeds

    SciTech Connect

    Zhang, P.; Shanklin, J.; Burton, J. W.; Upchurch, R. G.; Whittle, E.; Dewey, R. E.

    2008-11-01

    Stearic acid (18:0) is typically a minor component of soybean [Glycine max (L.) Merr.] oil, accounting for only 2 to 4% of the total fatty acid content. Increasing stearic acid levels of soybean oil would lead to enhanced oxidative stability, potentially reducing the need for hydrogenation, a process leading to the formation of undesirable trans fatty acids. Although mutagenesis strategies have been successful in developing soybean germplasm with elevated 18:0 levels in the seed oil, the specific gene mutations responsible for this phenotype were not known. We report a newly identified soybean gene, designated SACPD-C, that encodes a unique isoform of {Delta}{sup 9}-stearoyl-ACP-desaturase, the enzyme responsible for converting stearic acid to oleic acid (18:1). High levels of SACPD-C transcript were only detected in developing seed tissue, suggesting that the encoded desaturase functions to enhance oleic acid biosynthetic capacity as the immature seed is actively engaged in triacylglycerol production and storage. The participation of SACPD-C in storage triacylglycerol synthesis is further supported by the observation of mutations in this gene in two independent sources of elevated 18:0 soybean germplasm, A6 (30% 18:0) and FAM94-41 (9% 18:0). A molecular marker diagnostic for the FAM94-41 SACPD-C gene mutation strictly associates with the elevated 18:0 phenotype in a segregating population, and could thus serve as a useful tool in the development of cultivars with oils possessing enhanced oxidative stability.

  16. Effect of ACP-CPP Chewing Gum and Natural Chewable Products on Plaque pH, Calcium and Phosphate Concentration

    PubMed Central

    Sultan, Saima; Chaudhary, Seema; Manuja, Naveen; Kaur, Harsimran; Amit, Sinha Ashish; Lingesha, Ravishankar Telgi

    2016-01-01

    Introduction Numerous epidemiological studies have documented dental caries as the major public health problems throughout the world. It is gradually increasing in the underdeveloped and developing countries especially in children due to increasing popularity of refined sugars. Aim The aim of the study was to evaluate the effect of natural chewable products (Tulsi, sesame seeds, fennel seeds, coconut) and ACP-CPP chewing gum on plaque pH, calcium and phosphate concentration. Materials and Methods A randomized controlled trial, with a cross-over study design, was conducted. Ten subjects aged 15-17 years who agreed to refrain from oral hygiene practice for 48 hours prior to the sample collection were selected for the study. The baseline plaque pH, calcium and phosphate was measured and repeated after 5 and 30 minutes. It was ensured that each study participant was subjected to all the products making an effective sample of ten subjects per product. The data was statistically analysed. Results The mean pH in all the study groups increased after 5 minutes and 30 minutes compared to baseline, except for coconut group at 30 minutes and fennel group at 5 minutes. Highest increase in plaque calcium concentration was found in fennel group followed by recaldent and sesame, respectively. Whereas, the highest increase in plaque phosphate was found in recaldent group followed by sesame group and fennel group respectively. Conclusion Plant products can be effective, inexpensive, easily accessible methods of maintaining oral health. Further studies are recommended to confirm long term effects. PMID:27190943

  17. Selectivity of Pyridone- and Diphenyl Ether-Based Inhibitors for the Yersinia pestis FabV Enoyl-ACP Reductase.

    PubMed

    Neckles, Carla; Pschibul, Annica; Lai, Cheng-Tsung; Hirschbeck, Maria; Kuper, Jochen; Davoodi, Shabnam; Zou, Junjie; Liu, Nina; Pan, Pan; Shah, Sonam; Daryaee, Fereidoon; Bommineni, Gopal R; Lai, Cristina; Simmerling, Carlos; Kisker, Caroline; Tonge, Peter J

    2016-05-31

    The enoyl-ACP reductase (ENR) catalyzes the last reaction in the elongation cycle of the bacterial type II fatty acid biosynthesis (FAS-II) pathway. While the FabI ENR is a well-validated drug target in organisms such as Mycobacterium tuberculosis and Staphylococcus aureus, alternate ENR isoforms have been discovered in other pathogens, including the FabV enzyme that is the sole ENR in Yersinia pestis (ypFabV). Previously, we showed that the prototypical ENR inhibitor triclosan was a poor inhibitor of ypFabV and that inhibitors based on the 2-pyridone scaffold were more potent [Hirschbeck, M. (2012) Structure 20 (1), 89-100]. These studies were performed with the T276S FabV variant. In the work presented here, we describe a detailed examination of the mechanism and inhibition of wild-type ypFabV and the T276S variant. The T276S mutation significantly reduces the affinity of diphenyl ether inhibitors for ypFabV (20-fold → 100-fold). In addition, while T276S ypFabV generally displays an affinity for 2-pyridone inhibitors higher than that of the wild-type enzyme, the 4-pyridone scaffold yields compounds with similar affinity for both wild-type and T276S ypFabV. T276 is located at the N-terminus of the helical substrate-binding loop, and structural studies coupled with site-directed mutagenesis reveal that alterations in this residue modulate the size of the active site portal. Subsequently, we were able to probe the mechanism of time-dependent inhibition in this enzyme family by extending the inhibition studies to include P142W ypFabV, a mutation that results in a gain of slow-onset inhibition for the 4-pyridone PT156. PMID:27136302

  18. GENE EXPRESSION IN THE ASIAN CITRUS PSYLLID: VECTOR OF CITRUS GREENING (HEMIPTERA: PSYLLIDAE)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Production of a unigene set identified the putative functions of over 500 transcripts from the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). D. citri is the primary vector of Huanglongbing, HLB, which is a severe plant pathogenic bacterium that causes severe economic losses...

  19. Asian Citrus Psyllid, Genetic Basis of Immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We used a genomics approach to identify some of the genetic bases of D. citri immunity, identifying in particular genes associated with environmental and biological stresses. Only a few insecticides are being used to manage the Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae), to...

  20. Murraya paniculata (orange jasmine), a host and possible inoculum reservoir for Candidatus Liberibacter asiaticus, causal agent of Huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), considered the most serious vectored-pathogen of citrus, is transmitted in nature by the Asian citrus psyllid Diaphorina citri and the African citrus psyllid Trioza erytreae. In 1999, D. citri was discovered in southern Florida and has become established in FL and TX. Huanglon...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘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...

  2. Gene expression in Asian citrus psyllid adults feeding from Florida citrus: Application to biology and vector control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We used a genomics approach to identify some of the genetic basis of D. citri biology, identifying in particular genes associated with feeding, reproduction, pathology, and insecticide resistance. The Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae), is a highly competent vector ...

  3. Localized autoinoculation and dissemination of Isaria fumosorosea for control of the Asian citrus psyllid in South Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama, vectors the causal organism of citrus greening disease. Integrated strategies are needed to control D. citri in south Texas. Control approaches involving entomopathogenic fungi may be useful on ornamental and abandoned citrus and other rutaceous...

  4. The complete mitochondrial genome of the citrus red mite Panonychus citri (Acari: Tetranychidae): high genome rearrangement and extremely truncated tRNAs

    PubMed Central

    2010-01-01

    Background The family Tetranychidae (Chelicerata: Acari) includes ~1200 species, many of which are of agronomic importance. To date, mitochondrial genomes of only two Tetranychidae species have been sequenced, and it has been found that these two mitochondrial genomes are characterized by many unusual features in genome organization and structure such as gene order and nucleotide frequency. The scarcity of available sequence data has greatly impeded evolutionary studies in Acari (mites and ticks). Information on Tetranychidae mitochondrial genomes is quite important for phylogenetic evaluation and population genetics, as well as the molecular evolution of functional genes such as acaricide-resistance genes. In this study, we sequenced the complete mitochondrial genome of Panonychus citri (Family Tetranychidae), a worldwide citrus pest, and provide a comparison to other Acari. Results The mitochondrial genome of P. citri is a typical circular molecule of 13,077 bp, and contains the complete set of 37 genes that are usually found in metazoans. This is the smallest mitochondrial genome within all sequenced Acari and other Chelicerata, primarily due to the significant size reduction of protein coding genes (PCGs), a large rRNA gene, and the A + T-rich region. The mitochondrial gene order for P. citri is the same as those for P. ulmi and Tetranychus urticae, but distinctly different from other Acari by a series of gene translocations and/or inversions. The majority of the P. citri mitochondrial genome has a high A + T content (85.28%), which is also reflected by AT-rich codons being used more frequently, but exhibits a positive GC-skew (0.03). The Acari mitochondrial nad1 exhibits a faster amino acid substitution rate than other genes, and the variation of nucleotide substitution patterns of PCGs is significantly correlated with the G + C content. Most tRNA genes of P. citri are extremely truncated and atypical (44-65, 54.1 ± 4.1 bp), lacking either the T- or D-arm, as

  5. Biocontrol ability and putative mode of action of yeasts against Geotrichum citri-aurantii in citrus fruit.

    PubMed

    Ferraz, Luriany Pompeo; Cunha, Tatiane da; da Silva, Aline Caroline; Kupper, Katia Cristina

    2016-01-01

    Sour rot is a major postharvest disease of citrus fruit and is caused by the fungal pathogen Geotrichum citri-aurantii. A lack of chemicals certified for the control of this disease has led to the consideration of alternative methods and strategies, such as the use of yeasts as biocontrol agents. The purpose of the present study was to test the ability of yeasts isolated from leaves, flowers, fruit, and soil, and six Saccharomyces cerevisiae isolates to control citrus sour rot, to assess the mechanisms of action of the yeast isolates that were demonstrated to be effective for biocontrol, and to identify the most effective yeast isolates for the biocontrol of G. citri-aurantii. In in vivo assays, three yeast isolates (ACBL-23, ACBL-44, and ACBL-77) showed a potential for controlling sour rot in citrus fruits, both preventatively and curatively. Most of the eight yeast isolates that were assessed for a mechanism of action did not produce antifungal compounds in an amount sufficient to inhibit the growth of the pathogen. Additionally, nutrient competition among the yeast strains was not found to be a biocontrol strategy. Instead, killer activity and hydrolytic enzyme production were identified as the major mechanisms involved in the biocontrol activity of the yeasts. Isolates ACBL-23, ACBL-44, and ACBL-77, which controlled sour rot most effectively, were identified as Rhodotorula minuta, Candida azyma, and Aureobasidium pullulans, respectively. To our knowledge, this is the first report of the potential of C. azyma as a biological control agent against a postharvest pathogen and its ability to produce a killer toxin. PMID:27296964

  6. Identification and expression of a stearoyl-ACP desaturase gene responsible for oleic acid accumulation in Xanthoceras sorbifolia seeds.

    PubMed

    Zhao, Na; Zhang, Yuan; Li, Qiuqi; Li, Rufang; Xia, Xinli; Qin, Xiaowei; Guo, Huihong

    2015-02-01

    Xanthoceras sorbifolia Bunge is an oilseed tree that grows well on barren lands in dry climate. Its seeds contain a large amount of oil rich in oleic acid (18:1(Δ9)) and linoleic acid (18:2(Δ9, 12)). However, the molecular regulation of oil biosynthesis in X. sorbifolia seeds is poorly understood. Stearoyl-ACP desaturase (SAD, EC 1.14.99.6) is a plastid-localized soluble desaturase that catalyzes the conversion of stearic acid (18:0) to oleic acid, which plays a key role in determining the ratio of saturated to unsaturated fatty acids. In this study, a full-length cDNA of XsSAD was isolated from developing X. sorbifolia embryos. The XsSAD open reading frame had 1194-bp, encoding a polypeptide of 397 amino acids. XsSAD expression in Escherichia coli cells resulted in increased 18:1(Δ9) level, confirming the biological activity of the enzyme encoded by XsSAD. XsSAD expression in Arabidopsis ssi2 mutants partially restored the morphological phenotype and effectively increased the 18:1(Δ9) level. The levels of other unsaturated fatty acids synthesized with 18:1(Δ9) as the substrate also increased to some degree. XsSAD in X. sorbifolia had a much higher expression in embryos than in leaves and petals. XsSAD expression also correlated well with the oleic acid, unsaturated fatty acid, and total fatty acid levels in developing embryos. These data suggested that XsSAD determined the synthesis of oleic acid and contributed to the accumulation of unsaturated fatty acid and total oil in X. sorbifolia seeds. A preliminary tobacco rattle virus-based virus-induced gene silencing system established in X. sorbifolia can also be helpful for further analyzing the functions of XsSAD and other oil synthesis-related genes in woody plants. PMID:25528221

  7. Effect of CPP-ACP Paste on Enamel Carious Lesion of Primary Upper Anterior Teeth Assessed by Quantitative Light-Induced Fluorescence: A One-Year Clinical Trial.

    PubMed

    Sitthisettapong, Thanya; Doi, Takashi; Nishida, Yuhei; Kambara, Masaki; Phantumvanit, Prathip

    2015-01-01

    The purpose of this clinical trial was to evaluate the effect of 1 year of daily application of 10% w/v CPP-ACP (casein phosphopeptide-amorphous calcium phosphate) paste in addition to regular toothbrushing with fluoridated toothpaste on the remineralization of enamel carious lesions in preschool children using quantitative light-induced fluorescence (QLF). A total of 103 Thai children (aged 2(1)/2-3(1)/2 years) with high caries risk who had at least 1 enamel carious lesion (ICDAS 1-3) on the labial surface of the upper anterior teeth were assigned to receive either CPP-ACP paste (n = 53) or placebo control (n = 50) following toothbrushing with fluoridated toothpaste after lunch at school. QLF measurement was performed at baseline, 6 months and 1 year. At 1 year, a significant reduction in fluorescence loss (ΔF), lesion area and lesion volume (ΔQ; p ≤ 0.001) of the lesions were found over time in both groups. However, no significant difference was observed between the groups (p = 0.79, 0.98 and 0.88, respectively). There was no statistically significant difference between the odds of ΔQ transition to a stage of regression or arrest compared with progression from baseline to 1 year between the two groups (OR = 1.03, 95% CI 0.31-3.39). The daily application of 10% w/v CPP-ACP paste on a school day for 1 year resulted in no improvement of enamel carious lesion remineralization in the primary upper anterior teeth as assessed by QLF. The lesion improvement was not superior to remineralization from regular toothbrushing with fluoridated toothpaste alone in these children. PMID:26228178

  8. Enzymatic assembly of epothilones: the EpoC subunit and reconstitution of the EpoA-ACP/B/C polyketide and nonribosomal peptide interfaces.

    PubMed

    O'Connor, Sarah E; Chen, Huawei; Walsh, Christopher T

    2002-04-30

    The biosynthesis of epothilones, a family of hybrid polyketide (PK)/nonribosomal peptide (NRP) antitumor agents, provides an ideal system to study a hybrid PK/NRP natural product with significant biomedical value. Here the third enzyme involved in epothilone production, the five domain 195 kDa polyketide synthase (PKS) EpoC protein, has been expressed and purified from Escherichia coli. EpoC was combined with the first two enzymes of the epothilone biosynthesis pathway, the acyl carrier protein (ACP) domain of EpoA and EpoB, to reconstitute the early steps in epothilone biosynthesis. The acyltransferase (AT) domain of EpoC transfers the methylmalonyl moiety from methylmalonyl-CoA to the holo HS-acyl carrier protein (ACP) in an autoacylation reaction. The ketosynthase (KS) domain of EpoC decarboxylates the methylmalonyl-S-EpoC acyl enzyme to generate the carbon nucleophile that reacts with methylthiazolylcarboxyl-S-EpoB. The resulting condensation product can be reduced in the presence of NADPH by the ketoreductase (KR) domain of EpoC and then dehydrated by the dehydratase (DH) domain to produce the methylthiazolylmethylacrylyl-S-EpoC acyl enzyme intermediate that serves as the acyl donor for subsequent elongation of the epothilone chain. The acetyl-CoA donor can be replaced with propionyl-CoA, isobutyryl-CoA, and benzoyl-CoA and the acyl chains accepted by both EpoB and EpoC subunits to produce ethyl-, isopropyl-, and phenylthiazolylmethylacrylyl-S-EpoC acyl enzyme intermediates, suggesting that future combinatorial biosynthetic variations in epothilone assembly may be feasible. These results demonstrate in vitro reconstitution of both the PKS/NRPS interface (EpoA-ACP/B) and the NRPS/PKS interface (EpoB/C) in the assembly line for this antitumor natural product. PMID:11969430

  9. Cloning, characterization, and expression analysis of acyl-acyl carrier protein (ACP)-thioesterase B from seeds of Chinese Spicehush (Lindera communis).

    PubMed

    Dong, Shubin; Huang, Jiacong; Li, Yannan; Zhang, Jing; Lin, Shanzhi; Zhang, Zhixiang

    2014-05-25

    Acyl-acyl carrier protein (ACP) thioesterases (TE EC 3.1.2.14) are fatty acid biosynthesis key enzymes that determine fatty acid carbon chain length in most plant tissues. A full-length cDNA corresponding to one of the fatty acyl-ACP thioesterase (Fat) genes, designated LcFatB, was isolated from developing Lindera communis seeds using PCR and RACE with degenerate primers based on conserved sequences of multiple TE gene sequences obtained from GenBank. The 1788 bp cDNA had an open reading frame (ORF) of 1260 bp encoding a protein of 419 amino acids. The deduced amino acid sequence showed 61-73% identity to proteins in the FatB class of plant thioesterases. Real-time quantitative PCR analysis revealed that LcFatB was expressed in all tissues of L. communis, with the highest expression in the developing seeds 75days after flowering. Recombinant pET-MLcFatB was constructed using the pET-30 a vector and transformed into Escherichia coli BL21(DE3)△FadE, a strain that deleted the acyl-CoA dehydrogenase (FadE). SDS-PAGE analysis of proteins isolated from pET-MLcFatB E. coli cells after induction with IPTG revealed a protein band at ~40.5kDa, corresponding to the predicted size of LcFatB mature protein. The decanoic acid and lauric acid contents of the pET-MLcFatB transformant were increased significantly. These findings suggest that an LcFatB gene from a non-traditional oil-seed tree could be used to function as a saturated acyl-ACP thioesterase and could potentially be used to modify the fatty acid composition of seed oil from L. communis or other species through transgenic approaches. PMID:24631366

  10. The Crystal Structure of the Ivy delta4-16:0-ACP Desaturase Reveals Structural Details of the Oxidized Active Site and Potential Determinants of Regioselectivity

    SciTech Connect

    Guy,J.; Whittle, E.; Kumaran, D.; Lindqvist, Y.; Shanklin, J.

    2007-01-01

    The multifunctional acyl-acyl carrier protein (ACP) desaturase from Hedera helix (English ivy) catalyzes the {Delta}{sup 4} desaturation of 16:0-ACP and the{Delta}{sup 9} desaturation of 18:0-ACP and further desaturates{Delta}{sup 9}-16:1 or {Delta}{sup 9}-18:1 to the corresponding {Delta}{sup 4,9} dienes. The crystal structure of the enzyme has been solved to 1.95{angstrom} resolution, and both the iron-iron distance of 3.2{angstrom} and the presence of a {mu}-oxo bridge reveal this to be the only reported structure of a desaturase in the oxidized FeIII-FeIII form. Significant differences are seen between the oxidized active site and the reduced active site of the Ricinus communis (castor) desaturase; His{sup 227} coordination to Fe2 is lost, and the side chain of Glu{sup 224}, which bridges the two iron ions in the reduced structure, does not interact with either iron. Although carboxylate shifts have been observed on oxidation of other diiron proteins, this is the first example of the residue moving beyond the coordination range of both iron ions. Comparison of the ivy and castor structures reveal surface amino acids close to the annulus of the substrate-binding cavity and others lining the lower portion of the cavity that are potential determinants of their distinct substrate specificities. We propose a hypothesis that differences in side chain packing explains the apparent paradox that several residues lining the lower portion of the cavity in the ivy desaturase are bulkier than their equivalents in the castor enzyme despite the necessity for the ivy enzyme to accommodate three more carbons beyond the diiron site.

  11. Assessment of White Spot Lesions and In-Vivo Evaluation of the Effect of CPP-ACP on White Spot Lesions in Permanent Molars of Children

    PubMed Central

    Munjal, Deepti; Garg, Shalini; Dhindsa, Abhishek; Sidhu, Gagandeep Kaur

    2016-01-01

    Introduction As hindrance of remineralisation process occurs during orthodontic therapy resulting in decalcification of enamel because number of plaque retention sites increases due to banding and bonding of appliances to teeth. Aim The present analytic study was undertaken to assess the occurrence of white spot lesions in permanent molars of children with and without orthodontic therapy and to evaluate the effect of Casein PhosphoPeptide-Amorphous Calcium Phosphate (CPP-ACP) on white spot lesions in post-orthodontic patients in a given period of time. Materials and Methods The study comprised of examination of 679 first permanent molars which were examined to assess the occurrence of smooth surface white spot lesions in children of 8 to 16 years age group. Group I comprised subjects without any orthodontic treatment and Group II comprised of subjects who had undergone orthodontic therapy. The sample size was calculated using the epi-info6 computer package. Treatment group included 20 post-orthodontic patients examined with at least one white spot lesion within the enamel who received remineralizing cream (GC Tooth Mousse, Recaldent, GC Corporation.) i.e., CPP–ACP cream two times a day for 12 consecutive weeks. Computerized image analysis method was taken to evaluate white spot lesions. These frequency and percentages were compared with chi-square test. For comparison of numeric data, paired t-test was used. Results Of the total 278 (49.6%) first permanent molars showed occurrence of smooth surface white spot lesions out of 560 in Group I and 107 (89.9%) first permanent molars showed presence of white spot lesions out of 119 debanded first permanent molars of children examined in Group II. CPP-ACP therapy group showed reduction in severity of codes which was found to be highly significant after 12 weeks and eight weeks on gingival-third, p-value (<0.001) and significant after eight weeks and four weeks on middle-third according to ICDAS II criteria and

  12. Radiolabelling and positron emission tomography of PT70, a time-dependent inhibitor of InhA, the Mycobacterium tuberculosis enoyl-ACP reductase.

    PubMed

    Wang, Hui; Liu, Li; Lu, Yang; Pan, Pan; Hooker, Jacob M; Fowler, Joanna S; Tonge, Peter J

    2015-11-01

    PT70 is a diaryl ether inhibitor of InhA, the enoyl-ACP reductase in the Mycobacterium tuberculosis fatty acid biosynthesis pathway. It has a residence time of 24 min on the target, and also shows antibacterial activity in a mouse model of tuberculosis infection. Due to the interest in studying target tissue pharmacokinetics of PT70, we developed a method to radiolabel PT70 with carbon-11 and have studied its pharmacokinetics in mice and baboons using positron emission tomography. PMID:26227776

  13. Diel periodicity of pheromone release by females of Planococcus citri and Planococcus ficus and the temporal flight activity of their conspecific males

    NASA Astrophysics Data System (ADS)

    Levi-Zada, Anat; Fefer, Daniela; David, Maayan; Eliyahu, Miriam; Franco, José Carlos; Protasov, Alex; Dunkelblum, Ezra; Mendel, Zvi

    2014-08-01

    The diel periodicity of sex pheromone release was monitored in two mealybug species, Planococcus citri and Planococcus ficus (Hemiptera; Pseudococcidae), using sequential SPME/GCMS analysis. A maximal release of 2 ng/h pheromone by 9-12-day-old P. citri females occurred 1-2 h before the beginning of photophase. The highest release of pheromone by P. ficus females was 1-2 ng/2 h of 10-20-day-old females, approximately 2 h after the beginning of photophase. Mating resulted in termination of the pheromone release in both mealybug species. The temporal flight activity of the males was monitored in rearing chambers using pheromone baited delta traps. Males of both P. citri and P. ficus displayed the same flight pattern and began flying at 06:00 hours when the light was turned on, reaching a peak during the first and second hour of the photophase. Our results suggest that other biparental mealybug species display also diel periodicities of maximal pheromone release and response. Direct evaluation of the diel periodicity of the pheromone release by the automatic sequential analysis is convenient and will be very helpful in optimizing the airborne collection and identification of other unknown mealybug pheromones and to study the calling behavior of females. Considering this behavior pattern may help to develop more effective pheromone-based management strategies against mealybugs.

  14. Exposure to Diflubenzuron Results in an Up-Regulation of a Chitin Synthase 1 Gene in Citrus Red Mite, Panonychus citri (Acari: Tetranychidae)

    PubMed Central

    Xia, Wen-Kai; Ding, Tian-Bo; Niu, Jin-Zhi; Liao, Chong-Yu; Zhong, Rui; Yang, Wen-Jia; Liu, Bin; Dou, Wei; Wang, Jin-Jun

    2014-01-01

    Chitin synthase synthesizes chitin, which is critical for the arthropod exoskeleton. In this study, we cloned the cDNA sequences of a chitin synthase 1 gene, PcCHS1, in the citrus red mite, Panonychus citri (McGregor), which is one of the most economically important pests of citrus worldwide. The full-length cDNA of PcCHS1 contains an open reading frame of 4605 bp of nucleotides, which encodes a protein of 1535 amino acid residues with a predicted molecular mass of 175.0 kDa. A phylogenetic analysis showed that PcCHS1 was most closely related to CHS1 from Tetranychus urticae. During P. citri development, PcCHS1 was constantly expressed in all stages but highly expressed in the egg stage (114.8-fold higher than in the adult). When larvae were exposed to diflubenzuron (DFB) for 6 h, the mite had a significantly high mortality rate, and the mRNA expression levels of PcCHS1 were significantly enhanced. These results indicate a promising use of DFB to control P. citri, by possibly acting as an inhibitor in chitin synthesis as indicated by the up-regulation of PcCHS1 after exposure to DFB. PMID:24590130

  15. Exposure to diflubenzuron results in an up-regulation of a chitin synthase 1 gene in citrus red mite, Panonychus citri (Acari: Tetranychidae).

    PubMed

    Xia, Wen-Kai; Ding, Tian-Bo; Niu, Jin-Zhi; Liao, Chong-Yu; Zhong, Rui; Yang, Wen-Jia; Liu, Bin; Dou, Wei; Wang, Jin-Jun

    2014-01-01

    Chitin synthase synthesizes chitin, which is critical for the arthropod exoskeleton. In this study, we cloned the cDNA sequences of a chitin synthase 1 gene, PcCHS1, in the citrus red mite, Panonychus citri (McGregor), which is one of the most economically important pests of citrus worldwide. The full-length cDNA of PcCHS1 contains an open reading frame of 4605 bp of nucleotides, which encodes a protein of 1535 amino acid residues with a predicted molecular mass of 175.0 kDa. A phylogenetic analysis showed that PcCHS1 was most closely related to CHS1 from Tetranychus urticae. During P. citri development, PcCHS1 was constantly expressed in all stages but highly expressed in the egg stage (114.8-fold higher than in the adult). When larvae were exposed to diflubenzuron (DFB) for 6 h, the mite had a significantly high mortality rate, and the mRNA expression levels of PcCHS1 were significantly enhanced. These results indicate a promising use of DFB to control P. citri, by possibly acting as an inhibitor in chitin synthesis as indicated by the up-regulation of PcCHS1 after exposure to DFB. PMID:24590130

  16. Comparison of potato and asian citrus psyllid adult and nymph transcriptomes identified vector transcripts with potential involvement in circulative, propagative liberibacter transmission.

    PubMed

    Fisher, Tonja W; Vyas, Meenal; He, Ruifeng; Nelson, William; Cicero, Joseph M; Willer, Mark; Kim, Ryan; Kramer, Robin; May, Greg A; Crow, John A; Soderlund, Carol A; Gang, David R; Brown, Judith K

    2014-01-01

    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. PMID:25436509

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

    PubMed Central

    Fisher, Tonja W.; Vyas, Meenal; He, Ruifeng; Nelson, William; Cicero, Joseph M.; Willer, Mark; Kim, Ryan; Kramer, Robin; May, Greg A.; Crow, John A.; Soderlund, Carol A.; Gang, David R.; Brown, Judith K.

    2014-01-01

    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. PMID:25436509

  18. Type III polyketide synthase beta-ketoacyl-ACP starter unit and ethylmalonyl-CoA extender unit selectivity discovered by Streptomyces coelicolor genome mining.

    PubMed

    Song, Lijiang; Barona-Gomez, Francisco; Corre, Christophe; Xiang, Longkuan; Udwary, Daniel W; Austin, Michael B; Noel, Joseph P; Moore, Bradley S; Challis, Gregory L

    2006-11-22

    Polyketide synthases (PKSs) are involved in the biosynthesis of many important natural products. In bacteria, type III PKSs typically catalyze iterative decarboxylation and condensation reactions of malonyl-CoA building blocks in the biosynthesis of polyhydroxyaromatic products. Here it is shown that Gcs, a type III PKS encoded by the sco7221 ORF of the bacterium Streptomyces coelicolor, is required for biosynthesis of the germicidin family of 3,6-dialkyl-4-hydroxypyran-2-one natural products. Evidence consistent with Gcs-catalyzed elongation of specific beta-ketoacyl-ACP products of the fatty acid synthase FabH with ethyl- or methylmalonyl-CoA in the biosynthesis of germicidins is presented. Selectivity for beta-ketoacyl-ACP starter units and ethylmalonyl-CoA as an extender unit is unprecedented for type III PKSs, suggesting these enzymes may be capable of utilizing a far wider range of starter and extender units for natural product assembly than believed until now. PMID:17105255

  19. Antioxidant responses of citrus red mite, Panonychus citri (McGregor) (Acari: Tetranychidae), exposed to thermal stress.

    PubMed

    Yang, Li-Hong; Huang, Hai; Wang, Jin-Jun

    2010-12-01

    Relatively low or high temperatures are responsible for a variety of physiological stress responses in insects and mites. Induced thermal stress was recently associated with increased reactive oxygen species (ROS) generation, which caused oxidative damage. In this study, we examined the time-related effect of the relatively low (0, 5, 10, and 15 °C) or high (32, 35, 38, and 41 °C) temperatures on the activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), peroxidases (POX), and glutathione-S-transferase (GST), and the total antioxidant capacity (TEAC) of the citrus red mite, Panonychus citri (McGregor). The malondialdehyde (MDA) concentration, as a marker of lipid peroxidation in organisms, was also measured in the citrus red mite under thermal stress conditions. Results showed that SOD and GST activities were significantly increased and play an important role in the process of antioxidant response to thermal stress. Lipid peroxidation levels increased significantly (P<0.001) and changed in a time-dependent manner. CAT and POX activity, as well as TEAC, did not vary significantly and play a minor role to remove the ROS generation. These results suggest that thermal stress leads to oxidative stress and antioxidant enzymes play an important role in reducing oxidative damage in the citrus red mite. PMID:20709071

  20. Analysis of three Xanthomonas axonopodis pv. citri effector proteins in pathogenicity and their interactions with host plant proteins.

    PubMed

    Dunger, Germán; Garofalo, Cecilia G; Gottig, Natalia; Garavaglia, Betiana S; Rosa, María C Pereda; Farah, Chuck S; Orellano, Elena G; Ottado, Jorgelina

    2012-10-01

    Xanthomonas axonopodis pv. citri, the bacterium responsible for citrus canker, uses effector proteins secreted by a type III protein secretion system to colonize its hosts. Among the putative effector proteins identified for this bacterium, we focused on the analysis of the roles of AvrXacE1, AvrXacE2 and Xac3090 in pathogenicity and their interactions with host plant proteins. Bacterial deletion mutants in avrXacE1, avrXacE2 and xac3090 were constructed and evaluated in pathogenicity assays. The avrXacE1 and avrXacE2 mutants presented lesions with larger necrotic areas relative to the wild-type strain when infiltrated in citrus leaves. Yeast two-hybrid studies were used to identify several plant proteins likely to interact with AvrXacE1, AvrXacE2 and Xac3090. We also assessed the localization of these effector proteins fused to green fluorescent protein in the plant cell, and observed that they co-localized to the subcellular spaces in which the plant proteins with which they interacted were predicted to be confined. Our results suggest that, although AvrXacE1 localizes to the plant cell nucleus, where it interacts with transcription factors and DNA-binding proteins, AvrXacE2 appears to be involved in lesion-stimulating disease 1-mediated cell death, and Xac3090 is directed to the chloroplast where its function remains to be clarified. PMID:22435635

  1. Construction of EGFP-labeling system for visualizing the infection process of Xanthomonas axonopodis pv. citri in planta.

    PubMed

    Liu, Li-Ping; Deng, Zi-Niu; Qu, Jin-Wang; Yan, Jia-Wen; Catara, Vittoria; Li, Da-Zhi; Long, Gui-You; Li, Na

    2012-09-01

    Xanthomonas axonopodis pv. citri (Xac) is the causal agent of citrus bacterial canker, an economically important disease to world citrus industry. To monitor the infection process of Xac in different citrus plants, the enhanced green florescent protein (EGFP) visualizing system was constructed to visualize the propagation and localization in planta. First, the wild-type Xac was isolated from the diseased leaves of susceptible 'Bingtang' sweet orange, and then the isolated Xac was labeled with EGFP by triparental mating. After PCR identification, the growth kinetics and pathogenicity of the transformants were analyzed in comparison with the wild-type Xac. The EGFP-labeled bacteria were inoculated by spraying on the surface and infiltration in the mesophyll of 'Bingtang' sweet orange leaves. The bacterial cell multiplication and diffusion processes were observed directly under confocal laser scanning microscope at different intervals after inoculation. The results indicated that the EGFP-labeled Xac releasing clear green fluorescence light under fluorescent microscope showed the infection process and had the same pathogenicity as the wild type to citrus. Consequently, the labeled Xac demonstrated the ability as an efficient tool to monitor the pathogen infection. PMID:22674174

  2. Expression, purification, crystallization and preliminary X-ray analysis of YaeQ (XAC2396) from Xanthomonas axonopodis pv. citri

    SciTech Connect

    Guzzo, Cristiane R.; Nagem, Ronaldo A. P.; Galvão-Botton, Leonor M. P.; Guimarães, Beatriz G.; Medrano, Francisco J.; Barbosa, João A. R. G.; Farah, Chuck S.

    2005-05-01

    The first crystallographic study of a member of the YaeQ family of proteins, which are conserved in a small group of Gram-negative bacteria, most of which are animal or plant pathogens, is reported. Diffraction data were collected to 1.9 Å resolution and an interpretable electron-density map was obtained. Xanthomonas axonopodis pv. citri YaeQ (XAC2396) is a member of a family of bacterial proteins conserved in several Gram-negative pathogens. Here, the cloning, expression, purification and crystallization of the 182-residue (20.6 kDa) YaeQ protein are described. Recombinant YaeQ containing selenomethionine was crystallized in space group P2{sub 1} and crystals diffracted to 1.9 Å resolution at a synchrotron source. The unit-cell parameters are a = 39.75, b = 91.88, c = 48.03 Å, β = 108.37°. The calculated Matthews coefficient suggests the presence of two YaeQ molecules in the asymmetric unit. Initial experimental phases were calculated by the multiple-wavelength anomalous dispersion technique and an interpretable electron-density map was obtained.

  3. AFN-1252 is a potent inhibitor of enoyl-ACP reductase from Burkholderia pseudomallei—Crystal structure, mode of action, and biological activity

    PubMed Central

    Narasimha Rao, Krishnamurthy; Lakshminarasimhan, Anirudha; Joseph, Sarah; Lekshmi, Swathi U; Lau, Ming-Seong; Takhi, Mohammed; Sreenivas, Kandepu; Nathan, Sheila; Yusof, Rohana; Abd Rahman, Noorsaadah; Ramachandra, Murali; Antony, Thomas; Subramanya, Hosahalli

    2015-01-01

    Melioidosis is a tropical bacterial infection caused by Burkholderia pseudomallei (B. pseudomallei; Bpm), a Gram-negative bacterium. Current therapeutic options are largely limited to trimethoprim-sulfamethoxazole and β-lactam drugs, and the treatment duration is about 4 months. Moreover, resistance has been reported to these drugs. Hence, there is a pressing need to develop new antibiotics for Melioidosis. Inhibition of enoyl-ACP reducatase (FabI), a key enzyme in the fatty acid biosynthesis pathway has shown significant promise for antibacterial drug development. FabI has been identified as the major enoyl-ACP reductase present in B. pseudomallei. In this study, we evaluated AFN-1252, a Staphylococcus aureus FabI inhibitor currently in clinical development, for its potential to bind to BpmFabI enzyme and inhibit B. pseudomallei bacterial growth. AFN-1252 stabilized BpmFabI and inhibited the enzyme activity with an IC50 of 9.6 nM. It showed good antibacterial activity against B. pseudomallei R15 strain, isolated from a melioidosis patient (MIC of 2.35 mg/L). X-ray structure of BpmFabI with AFN-1252 was determined at a resolution of 2.3 Å. Complex of BpmFabI with AFN-1252 formed a symmetrical tetrameric structure with one molecule of AFN-1252 bound to each monomeric subunit. The kinetic and thermal melting studies supported the finding that AFN-1252 can bind to BpmFabI independent of cofactor. The structural and mechanistic insights from these studies might help the rational design and development of new FabI inhibitors. PMID:25644789

  4. Cloning and functional expression of an acyl-ACP thioesterase FatB type from Diploknema (Madhuca) butyracea seeds in Escherichia coli.

    PubMed

    Jha, J K; Maiti, M K; Bhattacharjee, A; Basu, A; Sen, P C; Sen, S K

    2006-01-01

    A cDNA of fatty acyl-acyl carrier protein (ACP) thioesterase (Fat) from developing seed of Madhuca butyracea has been cloned. The deduced amino acid sequence of the cDNA corresponding to the mature polypeptide showed 30-40% and 60-75% identity to the reported FatA and FatB class of plant thioesterases, respectively. This gene, MbFatB, is present as a single copy in M. butyracea genome and the MbFatB protein was detected clearly in seed tissues of this plant but not in that of Indian mustard (Brassica juncea). Heterologous expression of the MbFatB gene driven by different promoters in E. coli wild type and fatty acid beta-oxidation mutant (fadD88) strains resulted production of the recombinant protein with various fusion tags either as biologically inactive (insoluble) or functionally active forms. Expression of functionally active recombinant MbFatB in E. coli affected bacterial growth and cell morphology as well as changed the fatty acid profiles of the membrane lipid and the culture supernatant. Alteration of the fatty acid composition was directed predominantly towards palmitate and to a lesser extent myristate and oleate due to acyl chain termination activity of plant thioesterase in bacteria. Thus, this new MbFatB gene isolated from a non-traditional oil-seed tree can be used in future for transgenic development of oil-seed Brassica, a widely cultivated crop that expresses predominantly oleoyl-ACP thioesterase (FatA) in its seed tissue and has high amount of unwanted erucic acid in edible oil in order to alter the fatty acid profile in a desirable way. PMID:17092734

  5. AFN-1252 is a potent inhibitor of enoyl-ACP reductase from Burkholderia pseudomallei--Crystal structure, mode of action, and biological activity.

    PubMed

    Rao, Krishnamurthy Narasimha; Lakshminarasimhan, Anirudha; Joseph, Sarah; Lekshmi, Swathi U; Lau, Ming-Seong; Takhi, Mohammed; Sreenivas, Kandepu; Nathan, Sheila; Yusof, Rohana; Abd Rahman, Noorsaadah; Ramachandra, Murali; Antony, Thomas; Subramanya, Hosahalli

    2015-05-01

    Melioidosis is a tropical bacterial infection caused by Burkholderia pseudomallei (B. pseudomallei; Bpm), a Gram-negative bacterium. Current therapeutic options are largely limited to trimethoprim-sulfamethoxazole and β-lactam drugs, and the treatment duration is about 4 months. Moreover, resistance has been reported to these drugs. Hence, there is a pressing need to develop new antibiotics for Melioidosis. Inhibition of enoyl-ACP reducatase (FabI), a key enzyme in the fatty acid biosynthesis pathway has shown significant promise for antibacterial drug development. FabI has been identified as the major enoyl-ACP reductase present in B. pseudomallei. In this study, we evaluated AFN-1252, a Staphylococcus aureus FabI inhibitor currently in clinical development, for its potential to bind to BpmFabI enzyme and inhibit B. pseudomallei bacterial growth. AFN-1252 stabilized BpmFabI and inhibited the enzyme activity with an IC50 of 9.6 nM. It showed good antibacterial activity against B. pseudomallei R15 strain, isolated from a melioidosis patient (MIC of 2.35 mg/L). X-ray structure of BpmFabI with AFN-1252 was determined at a resolution of 2.3 Å. Complex of BpmFabI with AFN-1252 formed a symmetrical tetrameric structure with one molecule of AFN-1252 bound to each monomeric subunit. The kinetic and thermal melting studies supported the finding that AFN-1252 can bind to BpmFabI independent of cofactor. The structural and mechanistic insights from these studies might help the rational design and development of new FabI inhibitors. PMID:25644789

  6. Insights from computational analysis of full-length β-ketoacyl-[ACP] synthase-II cDNA isolated from American and African oil palms

    PubMed Central

    Bhore, Subhash J.; Cha, Thye S.; Amelia, Kassim; Shah, Farida H.

    2014-01-01

    Background: Palm oil derived from fruits (mesocarp) of African oil palm (Elaeis guineensis Jacq. Tenera) and American oil palm (E. oleifera) is important for food industry. Due to high yield, Elaeis guineensis (Tenera) is cultivated on commercial scale, though its oil contains high (~54%) level of saturated fatty acids. The rate-limiting activity of beta-ketoacyl-[ACP] synthase-II (KAS-II) is considered mainly responsible for the high (44%) level of palmitic acid (C16:0) in the oil obtained from E. guineensis. Objective: The objective of this study was to annotate KAS-II cDNA isolated from American and African oil palms. Materials and Methods: The full-length E. oleifera KAS-II (EoKAS-II) cDNA clone was isolated using random method of gene isolation. Whereas, the E. guineensis KAS-II (EgTKAS-II) cDNA was isolated using reverse transcriptase polymerase chain reaction (RT-PCR) technique; and missing ends were obtained by employing 5’and 3’ RACE technique. Results: The results show that EoKAS-II and EgTKAS-II open reading frames (ORFs) are of 1689 and 1721 bp in length, respectively. Further analysis of the both EoKAS-II and EgTKAS-II predicted protein illustrates that they contains conserved domains for ‘KAS-I and II’, ‘elongating’ condensing enzymes, ‘condensing enzymes super-family’, and ‘3-oxoacyl-[ACP] synthase II’. The predicted protein sequences shows 95% similarity with each other. Consecutively, the three active sites (Cys, His, and His) were identified in both proteins. However, difference in positions of two active Histidine (His) residues was noticed. Conclusion: These insights may serve as the foundation in understanding the variable activity of KAS-II in American and African oil palms; and cDNA clones could be useful in the genetic engineering of oil palms. PMID:24678202

  7. The CERTO and CITRIS Instruments for Radio Scintillation and Electron Density Tomography from the C/NOFS, COSMIC, NPSAT1 and STPSAT1 Satellites

    NASA Astrophysics Data System (ADS)

    Bernhardt, P. A.; Siefring, C. L.

    2004-05-01

    A new constellation of radio beacon and radio beacon receivers will be providing global measurements of radio scintillations and total electron content (TEC) for near real time measurements of the ionosphere. This constellation is comprised of the NRL Coherent Electromagnetic Radio Tomography (CERTO) beacons on the Communications/Navigation Forecast Outage System (C/NOFS) satellite, the six Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) satellites, and the Naval Postgraduate (NPSAT1) Satellite. These satellites will be launched in the time period of 2004 through 2006. The CERTO beacons operating at 150.012, 400.032, and 1066.752 MHz will be transmitting to ground receivers located in chains to acquire TEC data for computerized ionospheric tomography (CIT). In addition, in early 2006 a five frequency receiver will be placed in low earth orbit with the United States Air Force Space Test Program (STPSAT1) satellite. This CITRIS receiver will use radio beacon transmissions from the French DORIS network of ground beacons at 401.25 and 2036.25 MHz and space-based beacons at 150, 400 and 1067 MHz to measure the earth's ionosphere. On board tracking software will lock onto Doppler shifted frequencies to determine total electron content (TEC) and scintillation parameters. The STPSAT1 will be launched along with a companion satellite (NPSAT1) which carries the CERTO radio beacon and a Langmuir probe. All of the CERTO beacons as well as the ionospheric sensors on STPSAT1 and NPSAT1 are being constructed at the Naval Research Laboratory. The data obtained using the CITRIS instrument will provide a global description of the ionosphere from orbits with inclinations ranging from 15 degrees to 70 degrees and altitudes from 375 to 800 km. The tandem operations of the CITRIS and CERTO instruments will provide the fully low-earth-orbit based occultation measurements of the ionosphere. All of the data will be available for rapid assimilation

  8. Deuterium-Labeled Precursor Feeding Reveals a New pABA-Containing Meroterpenoid from the Mango Pathogen Xanthomonas citri pv. mangiferaeindicae.

    PubMed

    Saleh, Hesham; Petras, Daniel; Mainz, Andi; Kerwat, Dennis; Nalbantsoy, Ayse; Erzurumlu, Yalcin; Süssmuth, Roderich D

    2016-06-24

    A new para-aminobenzoic-acid-containing natural product from the mango pathogenic organism Xanthomonas citri pv. mangiferaeindicae is described. By means of stable isotope precursor feeding combined with nontargeted LC-MS/MS, the generated spectra were clustered and visualized in a molecular network. This led to the identification of a new member of the meroterpenoids, termed xanthomonic acid, which is composed of an isoprenylated para-aminobenzoic acid. In vitro cytotoxicity assays demonstrated activity of xanthomonic acid against several human cancer cell lines by induction of autophagy. PMID:27232656

  9. Analysis of Transcriptome Differences between Resistant and Susceptible Strains of the Citrus Red Mite Panonychus citri (Acari: Tetranychidae)

    PubMed Central

    Liu, Bin; Jiang, Gaofei; Zhang, Yunfei; Li, Junli; Li, Xiaojiao; Yue, Jiansu; Chen, Fei; Liu, Haoqiang; Li, Hongjun; Zhu, Shiping; Wang, Jinjun; Ran, Chun

    2011-01-01

    Background The citrus red mite is a worldwide citrus pest and a common sensitizing allergen of asthma and rhinitis. It has developed strong resistance to many registered acaricides, However, the molecular mechanisms of resistance remain unknown. we therefore used next generation sequencing technology to investigate the global transcriptomes between resistant strains and susceptible strains. Results We obtained 34,159, 30,466 and 32,217 unigenes by assembling the SS reads, RS reads and SS&RS reads respectively. There are total 17,581 annotated unigenes from SS&RS reads by BLAST searching databases of nr, the Clusters of Orthologous Groups (COGs) and Kyoto Encyclopedia of Genes and Genomes (KEGG) with an E-value ≤ 1e-5, in which 7,075 unigenes were annotated in the COG database, 12, 712 unigenes were found in the KEGG database and 3,812 unigenes were assigned to Gene ontology (GO). Moreover, 2,701 unigenes were judged to be the differentially expressed genes (DEGs) based on the uniquely mapped reads. There are 219 pathways in all annotated unigenes and 198 pathways in DEGs that mapped to the KEGG database. We identified 211 metabolism genes and target genes related to general insecticide resistance such as P450 and Cytochrome b, and further compared their differences between RS and SS. Meanwhile, we identified 105 and 194 genes related to growth and reproduction, respectively, based on the mode of action of Hexythiazox. After further analyses, we found variation in sequences but not in gene expression related to mite growth and reproduction between different strains. Conclusion To our knowledge, this is the first comparative transcriptome study to discover candidate genes involved in phytophagous mite resistance. This study identified differential unigenes related to general pesticide resistance and organism growth and reproduction in P. citri. The assembled, annotated transcriptomes provide a valuable genomic resource for further understanding the molecular basis

  10. Genome-wide mutagenesis of Xanthomonas axonopodis pv. citri reveals novel genetic determinants and regulation mechanisms of biofilm formation.

    PubMed

    Li, Jinyun; Wang, Nian

    2011-01-01

    Xanthomonas axonopodis pv. citri (Xac) causes citrus canker disease, a major threat to citrus production worldwide. Accumulating evidence suggests that the formation of biofilms on citrus leaves plays an important role in the epiphytic survival of this pathogen prior to the development of canker disease. However, the process of Xac biofilm formation is poorly understood. Here, we report a genome-scale study of Xac biofilm formation in which we identified 92 genes, including 33 novel genes involved in biofilm formation and 7 previously characterized genes, colR, fhaB, fliC, galU, gumD, wxacO, and rbfC, known to be important for Xac biofilm formation. In addition, 52 other genes with defined or putative functions in biofilm formation were identified, even though they had not previously reported been to be associated with biofilm formation. The 92 genes were isolated from 292 biofilm-defective mutants following a screen of a transposon insertion library containing 22,000 Xac strain 306 mutants. Further analyses indicated that 16 of the novel genes are involved in the production of extracellular polysaccharide (EPS) and/or lipopolysaccharide (LPS), 7 genes are involved in signaling and regulatory pathways, and 5 genes have unknown roles in biofilm formation. Furthermore, two novel genes, XAC0482, encoding a haloacid dehalogenase-like phosphatase, and XAC0494 (designated as rbfS), encoding a two-component sensor protein, were confirmed to be biofilm-related genes through complementation assays. Our data demonstrate that the formation of mature biofilm requires EPS, LPS, both flagellum-dependent and flagellum-independent cell motility, secreted proteins and extracellular DNA. Additionally, multiple signaling pathways are involved in Xac biofilm formation. This work is the first report on a genome-wide scale of the genetic processes of biofilm formation in plant pathogenic bacteria. The report provides significant new information about the genetic determinants and

  11. Modifications of Xanthomonas axonopodis pv. citri lipopolysaccharide affect the basal response and the virulence process during citrus canker.

    PubMed

    Petrocelli, Silvana; Tondo, María Laura; Daurelio, Lucas D; Orellano, Elena G

    2012-01-01

    Xanthomonas axonopodis pv. citri (Xac) is the phytopathogen responsible for citrus canker, one of the most devastating citrus diseases in the world. A broad range of pathogens is recognized by plants through so-called pathogen-associated molecular patterns (PAMPs), which are highly conserved fragments of pathogenic molecules. In plant pathogenic bacteria, lipopolisaccharyde (LPS) is considered a virulence factor and it is being recognized as a PAMP. The study of the participation of Xac LPS in citrus canker establishment could help to understand the molecular bases of this disease. In the present work we investigated the role of Xac LPS in bacterial virulence and in basal defense during the interaction with host and non host plants. We analyzed physiological features of Xac mutants in LPS biosynthesis genes (wzt and rfb303) and the effect of these mutations on the interaction with orange and tobacco plants. Xac mutants showed an increased sensitivity to external stresses and differences in bacterial motilities, in vivo and in vitro adhesion and biofilm formation. Changes in the expression levels of the LPS biosynthesis genes were observed in a medium that mimics the plant environment. Xacwzt exhibited reduced virulence in host plants compared to Xac wild-type and Xacrfb303. However, both mutant strains produced a lower increase in the expression levels of host plant defense-related genes respect to the parental strain. In addition, Xac LPS mutants were not able to generate HR during the incompatible interaction with tobacco plants. Our findings indicate that the structural modifications of Xac LPS impinge on other physiological attributes and lead to a reduction in bacterial virulence. On the other hand, Xac LPS has a role in the activation of basal defense in host and non host plants. PMID:22792211

  12. Expression, crystallization and preliminary crystallographic analysis of SufE (XAC2355) from Xanthomonas axonopodis pv. citri

    SciTech Connect

    Guzzo, Cristiane R.; Silva, Lucicleide R.; Galvão-Botton, Leonor M. P.; Barbosa, João A. R. G.; Farah, Chuck S.

    2006-03-01

    Cloning, expression, purification, crystallization and data collection are reported for a member of the SufE family of proteins involved in the biosynthesis of Fe–S clusters in prokaryotes. Diffraction data were collected to 1.9 Å resolution and an interpretable electron-density map has been obtained by molecular replacement. Xanthomonas axonopodis pv. citri (Xac) SufE (XAC2355) is a member of a family of bacterial proteins that are conserved in several pathogens and phytopathogens. The Escherichia coli suf operon is involved in iron–sulfur cluster biosynthesis under iron-limitation and stress conditions. It has recently been demonstrated that SufE and SufS form a novel two-component cysteine desulfarase in which SufS catalyses the conversion of l-cysteine to l-alanine, forming a protein-bound persulfide intermediate. The S atom is then transferred to SufE, from which it is subsequently transferred to target molecules or reduced to sulfide in solution. Here, the cloning, expression, crystallization and phase determination of Xac SufE crystals are described. Recombinant SufE was crystallized in space group P2{sub 1}2{sub 1}2{sub 1} and diffracted to 1.9 Å resolution at a synchrotron source. The unit-cell parameters are a = 45.837, b = 58.507, c = 98.951 Å, α = β = γ = 90°. The calculated Matthews coefficient indicated the presence of two molecules in the asymmetric unit. Phasing was performed by molecular-replacement using E. coli SufE as a model (PDB code 1mzg) and an interpretable map was obtained.

  13. [Rapid Identification of Epicarpium Citri Grandis via Infrared Spectroscopy and Fluorescence Spectrum Imaging Technology Combined with Neural Network].

    PubMed

    Pan, Sha-sha; Huang, Fu-rong; Xiao, Chi; Xian, Rui-yi; Ma, Zhi-guo

    2015-10-01

    To explore rapid reliable methods for detection of Epicarpium citri grandis (ECG), the experiment using Fourier Transform Attenuated Total Reflection Infrared Spectroscopy (FTIR/ATR) and Fluorescence Spectrum Imaging Technology combined with Multilayer Perceptron (MLP) Neural Network pattern recognition, for the identification of ECG, and the two methods are compared. Infrared spectra and fluorescence spectral images of 118 samples, 81 ECG and 37 other kinds of ECG, are collected. According to the differences in tspectrum, the spectra data in the 550-1 800 cm(-1) wavenumber range and 400-720 nm wavelength are regarded as the study objects of discriminant analysis. Then principal component analysis (PCA) is applied to reduce the dimension of spectroscopic data of ECG and MLP Neural Network is used in combination to classify them. During the experiment were compared the effects of different methods of data preprocessing on the model: multiplicative scatter correction (MSC), standard normal variable correction (SNV), first-order derivative(FD), second-order derivative(SD) and Savitzky-Golay (SG). The results showed that: after the infrared spectra data via the Savitzky-Golay (SG) pretreatment through the MLP Neural Network with the hidden layer function as sigmoid, we can get the best discrimination of ECG, the correct percent of training set and testing set are both 100%. Using fluorescence spectral imaging technology, corrected by the multiple scattering (MSC) results in the pretreatment is the most ideal. After data preprocessing, the three layers of the MLP Neural Network of the hidden layer function as sigmoid function can get 100% correct percent of training set and 96.7% correct percent of testing set. It was shown that the FTIR/ATR and fluorescent spectral imaging technology combined with MLP Neural Network can be used for the identification study of ECG and has the advantages of rapid, reliable effect. PMID:26904814

  14. Modifications of Xanthomonas axonopodis pv. citri Lipopolysaccharide Affect the Basal Response and the Virulence Process during Citrus Canker

    PubMed Central

    Petrocelli, Silvana; Tondo, María Laura; Daurelio, Lucas D.; Orellano, Elena G.

    2012-01-01

    Xanthomonas axonopodis pv. citri (Xac) is the phytopathogen responsible for citrus canker, one of the most devastating citrus diseases in the world. A broad range of pathogens is recognized by plants through so-called pathogen-associated molecular patterns (PAMPs), which are highly conserved fragments of pathogenic molecules. In plant pathogenic bacteria, lipopolisaccharyde (LPS) is considered a virulence factor and it is being recognized as a PAMP. The study of the participation of Xac LPS in citrus canker establishment could help to understand the molecular bases of this disease. In the present work we investigated the role of Xac LPS in bacterial virulence and in basal defense during the interaction with host and non host plants. We analyzed physiological features of Xac mutants in LPS biosynthesis genes (wzt and rfb303) and the effect of these mutations on the interaction with orange and tobacco plants. Xac mutants showed an increased sensitivity to external stresses and differences in bacterial motilities, in vivo and in vitro adhesion and biofilm formation. Changes in the expression levels of the LPS biosynthesis genes were observed in a medium that mimics the plant environment. Xacwzt exhibited reduced virulence in host plants compared to Xac wild-type and Xacrfb303. However, both mutant strains produced a lower increase in the expression levels of host plant defense-related genes respect to the parental strain. In addition, Xac LPS mutants were not able to generate HR during the incompatible interaction with tobacco plants. Our findings indicate that the structural modifications of Xac LPS impinge on other physiological attributes and lead to a reduction in bacterial virulence. On the other hand, Xac LPS has a role in the activation of basal defense in host and non host plants. PMID:22792211

  15. Assessment of Prey Preference by the Generalist Predator, Mallada basalis (Walker), When Offered Two Species of Spider Mites, Tetranychus kanzawai Kishida and Panonychus citri (McGregor) on Papaya

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated potential prey preference of the generalist predator Mallada basalis (Walker) when offered two mites, Tetranychus kanzawai Kishida and Panonychus citri (McGregor), both important pests on papaya. Laboratory choice tests revealed that none of the three larval instars of M. basalis sho...

  16. Characterization of the Asian Citrus Psyllid Transcriptome

    PubMed Central

    Reese, Justin; Christenson, Matthew K.; Leng, Nan; Saha, Surya; Cantarel, Brandi; Lindeberg, Magdalen; Tamborindeguy, Cecilia; MacCarthy, Justin; Weaver, Daniel; Trease, Andrew J.; Ready, Steven V.; Davis, Vincent M.; McCormick, Courtney; Haudenschild, Christian; Han, Shunsheng; Johnson, Shannon L.; Shelby, Kent S.; Huang, Hong; Bextine, Blake R.; Shatters, Robert G.; Hall, David G.; Davis, Paul H.; Hunter, Wayne B.

    2014-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a vector for the causative agents of Huanglongbing, which threatens citrus production worldwide. This study reports and discusses the first D. citri transcriptomes, encompassing the three main life stages of D. citri, egg, nymph and adult. The transcriptomes were annotated using Gene Ontology (GO) and insecticide-related genes within each life stage were identified to aid the development of future D. citri insecticides. Transcriptome assemblies and other sequence data are available for download at the International Asian Citrus Psyllid Genome Consortium website [http://psyllid.org/download] and at NCBI [http://www.ncbi.nlm.nih.gov/bioproject/29447]. PMID:24511328

  17. Characterization and functional analysis of a novel glutathione S-transferase gene potentially associated with the abamectin resistance in Panonychus citri (McGregor).

    PubMed

    Liao, Chong-Yu; Xia, Wen-Kai; Feng, Ying-Cai; Li, Gang; Liu, Hai; Dou, Wei; Wang, Jin-Jun

    2016-09-01

    The citrus red mite, Panonychus citri (McGregor), a major citrus pest distributed worldwide, has been found to be resistant to various insecticides and acaricides used in China. However, the molecular mechanisms associated with the abamectin resistance in this species have not yet been reported. In this study, results showed over-expression of a novel glutathione S-transferases (GSTs) gene (PcGSTm5) in abamectin-resistant P. citri. Quantitative real-time PCR analysis showed that the transcripts of PcGSTm5 were also significantly up-regulated after exposure to abamectin and the maximum mRNA expression level at nymphal stage. The recombinant protein of PcGSTm5-pET-28a produced by Escherichia coli showed a pronounced activity toward the conjugates of 1-chloro-2,4 dinitrobenzene (CDNB) and glutathione (GSH). The kinetics of CDNB and GSH and its optimal pH and thermal stability were also determined. Reverse genetic study through a new method of leaf-mediated dsRNA feeding further support a link between the expression of PcGSTm5 and abamectin resistance. However, no direct evidence was found in metabolism or inhibition assays to confirm the hypothesis that PcGSTm5 can metabolize abamectin. Finally, it is here speculated that PcGSTm5 may play a role in abamectin detoxification through other pathway such as the antioxidant protection. PMID:27521916

  18. Physiological function of mycobacterial mtFabD, an essential malonyl-CoA:AcpM transacylase of type 2 fatty acid synthase FASII, in yeast mct1Delta cells.

    PubMed

    Gurvitz, Aner

    2009-01-01

    Mycobacterium tuberculosis mtFabD is an essential malonyl-CoA:AcpM transacylase and is important for vital protein-protein interactions within type 2 fatty acid synthase FASII. mtFabD contacts KasA, KasB, FabH, InhA, and possibly also HadAB, HadBC, and FabG1/MabA. Disruption of mtFabD's interactions during FASII has been proposed for drug development. Here, the gene for a mitochondrially targeted mtFabD was ectopically expressed in Saccharomyces cerevisiae mct1Delta mutant cells lacking the corresponding mitochondrial malonyl-CoA transferase Mct1p, allowing the mutants to recover their abilities to respire on glycerol and synthesize lipoic acid. Hence, mtFabD could physiologically function in an environment lacking holo-AcpM or other native interaction partners. PMID:19859569

  19. Modulation of medium-chain fatty acid synthesis in Synechococcus sp. PCC 7002 by replacing FabH with a Chaetoceros Ketoacyl-ACP synthase

    DOE PAGESBeta

    Gu, Huiya; Jinkerson, Robert E.; Davies, Fiona K.; Sisson, Lyle A.; Schneider, Philip E.; Posewitz, Matthew C.

    2016-05-26

    The isolation or engineering of algal cells synthesizing high levels of medium-chain fatty acids (MCFAs) is attractive to mitigate the high clouding point of longer chain fatty acids in algal based biodiesel. To develop a more informed understanding of MCFA synthesis in photosynthetic microorganisms, we isolated several algae from Great Salt Lake and screened this collection for MCFA accumulation to identify strains naturally accumulating high levels of MCFA. A diatom, Chaetoceros sp. GSL56, accumulated particularly high levels of C14 (up to 40%), with the majority of C14 fatty acids allocated in triacylglycerols. Using whole cell transcriptome sequencing and de novomore » assembly, putative genes encoding fatty acid synthesis enzymes were identified. Enzymes from this Chaetoceros sp. were expressed in the cyanobacterium Synechococcus sp. PCC 7002 to validate gene function and to determine whether eukaryotic enzymes putatively lacking bacterial evolutionary control mechanisms could be used to improve MCFA production in this promising production strain. Replacement of the Synechococcus 7002 native FabH with a Chaetoceros ketoacyl-ACP synthase Ill increased MCFA synthesis up to fivefold. In conclusion, the level of increase is dependent on promoter strength and culturing conditions.« less

  20. Modulation of Medium-Chain Fatty Acid Synthesis in Synechococcus sp. PCC 7002 by Replacing FabH with a Chaetoceros Ketoacyl-ACP Synthase

    PubMed Central

    Gu, Huiya; Jinkerson, Robert E.; Davies, Fiona K.; Sisson, Lyle A.; Schneider, Philip E.; Posewitz, Matthew C.

    2016-01-01

    The isolation or engineering of algal cells synthesizing high levels of medium-chain fatty acids (MCFAs) is attractive to mitigate the high clouding point of longer chain fatty acids in algal based biodiesel. To develop a more informed understanding of MCFA synthesis in photosynthetic microorganisms, we isolated several algae from Great Salt Lake and screened this collection for MCFA accumulation to identify strains naturally accumulating high levels of MCFA. A diatom, Chaetoceros sp. GSL56, accumulated particularly high levels of C14 (up to 40%), with the majority of C14 fatty acids allocated in triacylglycerols. Using whole cell transcriptome sequencing and de novo assembly, putative genes encoding fatty acid synthesis enzymes were identified. Enzymes from this Chaetoceros sp. were expressed in the cyanobacterium Synechococcus sp. PCC 7002 to validate gene function and to determine whether eukaryotic enzymes putatively lacking bacterial evolutionary control mechanisms could be used to improve MCFA production in this promising production strain. Replacement of the Synechococcus 7002 native FabH with a Chaetoceros ketoacyl-ACP synthase III increased MCFA synthesis up to fivefold. The level of increase is dependent on promoter strength and culturing conditions. PMID:27303412

  1. Measurement of the Branching Fraction and Photon Energy Moments of B→Xsγ and ACP(B→Xs+dγ)

    NASA Astrophysics Data System (ADS)

    Aubert, B.; Barate, R.; Bona, M.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Tisserand, V.; Zghiche, A.; Grauges, E.; Palano, A.; Chen, J. C.; Qi, N. D.; Rong, G.; Wang, P.; Zhu, Y. S.; Eigen, G.; Ofte, I.; Stugu, B.; Abrams, G. S.; Battaglia, M.; Brown, D. N.; Button-Shafer, J.; Cahn, R. N.; Charles, E.; Gill, M. S.; Groysman, Y.; Jacobsen, R. G.; Kadyk, J. A.; Kerth, L. T.; Kolomensky, Yu. G.; Kukartsev, G.; Lynch, G.; Mir, L. M.; Oddone, P. J.; Orimoto, T. J.; Pripstein, M.; Roe, N. A.; Ronan, M. T.; Wenzel, W. A.; Del Amo Sanchez, P.; Barrett, M.; Ford, K. E.; Harrison, T. J.; Hart, A. J.; Hawkes, C. M.; Morgan, S. E.; Watson, A. T.; Goetzen, K.; Held, T.; Koch, H.; Lewandowski, B.; Pelizaeus, M.; Peters, K.; Schroeder, T.; Steinke, M.; Boyd, J. T.; Burke, J. P.; Cottingham, W. N.; Walker, D.; Cuhadar-Donszelmann, T.; Fulsom, B. G.; Hearty, C.; Knecht, N. S.; Mattison, T. S.; McKenna, J. A.; Khan, A.; Kyberd, P.; Saleem, M.; Sherwood, D. J.; Teodorescu, L.; Blinov, V. E.; Bukin, A. D.; Druzhinin, V. P.; Golubev, V. B.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu; Best, D. S.; Bondioli, M.; Bruinsma, M.; Chao, M.; Curry, S.; Eschrich, I.; Kirkby, D.; Lankford, A. J.; Lund, P.; Mandelkern, M.; Mommsen, R. K.; Roethel, W.; Stoker, D. P.; Abachi, S.; Buchanan, C.; Foulkes, S. D.; Gary, J. W.; Long, O.; Shen, B. C.; Wang, K.; Zhang, L.; Hadavand, H. K.; Hill, E. J.; Paar, H. P.; Rahatlou, S.; Sharma, V.; Berryhill, J. W.; Campagnari, C.; Cunha, A.; Dahmes, B.; Hong, T. M.; Kovalskyi, D.; Richman, J. D.; Beck, T. W.; Eisner, A. M.; Flacco, C. J.; Heusch, C. A.; Kroseberg, J.; Lockman, W. S.; Nesom, G.; Schalk, T.; Schmitz, R. E.; Schumm, B. A.; Seiden, A.; Spradlin, P.; Williams, D. C.; Wilson, M. G.; Albert, J.; Chen, E.; Dvoretskii, A.; Fang, F.; Hitlin, D. G.; Narsky, I.; Piatenko, T.; Porter, F. C.; Ryd, A.; Samuel, A.; Mancinelli, G.; Meadows, B. T.; Sokoloff, M. D.; Blanc, F.; Bloom, P. C.; Chen, S.; Ford, W. T.; Hirschauer, J. F.; Kreisel, A.; Nauenberg, U.; Olivas, A.; Ruddick, W. O.; Smith, J. G.; Ulmer, K. A.; Wagner, S. R.; Zhang, J.; Chen, A.; Eckhart, E. A.; Soffer, A.; Toki, W. H.; Wilson, R. J.; Winklmeier, F.; Zeng, Q.; Altenburg, D. D.; Feltresi, E.; Hauke, A.; Jasper, H.; Petzold, A.; Spaan, B.; Brandt, T.; Klose, V.; Lacker, H. M.; Mader, W. F.; Nogowski, R.; Schubert, J.; Schubert, K. R.; Schwierz, R.; Sundermann, J. E.; Volk, A.; Bernard, D.; Bonneaud, G. R.; Grenier, P.; Latour, E.; Thiebaux, Ch.; Verderi, M.; Bard, D. J.; Clark, P. J.; Gradl, W.; Muheim, F.; Playfer, S.; Robertson, A. I.; Xie, Y.; Andreotti, M.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cibinetto, G.; Luppi, E.; Negrini, M.; Petrella, A.; Piemontese, L.; Prencipe, E.; Anulli, F.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Pacetti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Buzzo, A.; Capra, R.; Contri, R.; Lo Vetere, M.; Macri, M. M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Santroni, A.; Tosi, S.; Brandenburg, G.; Chaisanguanthum, K. S.; Morii, M.; Wu, J.; Dubitzky, R. S.; Marks, J.; Schenk, S.; Uwer, U.; Bhimji, W.; Bowerman, D. A.; Dauncey, P. D.; Egede, U.; Flack, R. L.; Nash, J. A.; Nikolich, M. B.; Panduro Vazquez, W.; Chai, X.; Charles, M. J.; Mallik, U.; Meyer, N. T.; Ziegler, V.; Cochran, J.; Crawley, H. B.; Dong, L.; Eyges, V.; Meyer, W. T.; Prell, S.; Rosenberg, E. I.; Rubin, A. E.; Gritsan, A. V.; Fritsch, M.; Schott, G.; Arnaud, N.; Davier, M.; Grosdidier, G.; Höcker, A.; Le Diberder, F.; Lepeltier, V.; Lutz, A. M.; Oyanguren, A.; Pruvot, S.; Rodier, S.; Roudeau, P.; Schune, M. H.; Stocchi, A.; Wang, W. F.; Wormser, G.; Cheng, C. H.; Lange, D. J.; Wright, D. M.; Chavez, C. A.; Forster, I. J.; Fry, J. R.; Gabathuler, E.; Gamet, R.; George, K. A.; Hutchcroft, D. E.; Payne, D. J.; Schofield, K. C.; Touramanis, C.; Bevan, A. J.; di Lodovico, F.; Menges, W.; Sacco, R.; Cowan, G.; Flaecher, H. U.; Hopkins, D. A.; Jackson, P. S.; McMahon, T. R.; Ricciardi, S.; Salvatore, F.; Wren, A. C.; Brown, D. N.; Davis, C. L.; Allison, J.; Barlow, N. R.; Barlow, R. J.; Chia, Y. M.; Edgar, C. L.; Lafferty, G. D.; Naisbit, M. T.; Williams, J. C.; Yi, J. I.; Chen, C.; Hulsbergen, W. D.; Jawahery, A.; Lae, C. K.; Roberts, D. A.; Simi, G.; Blaylock, G.; Dallapiccola, C.; Hertzbach, S. S.; Li, X.; Moore, T. B.; Saremi, S.; Staengle, H.; Cowan, R.; Sciolla, G.; Sekula, S. J.; Spitznagel, M.; Taylor, F.; Yamamoto, R. K.; Kim, H.; Patel, P. M.; Robertson, S. H.; Lazzaro, A.; Lombardo, V.; Palombo, F.; Bauer, J. M.; Cremaldi, L.; Eschenburg, V.; Godang, R.; Kroeger, R.; Sanders, D. A.; Summers, D. J.; Zhao, H. W.; Brunet, S.; Côté, D.; Taras, P.; Viaud, F. B.; Nicholson, H.; Cavallo, N.; de Nardo, G.; Fabozzi, F.; Gatto, C.; Lista, L.; Monorchio, D.; Paolucci, P.; Piccolo, D.; Sciacca, C.; Baak, M.; Raven, G.; Snoek, H. L.; Jessop, C. P.; Losecco, J. M.; Allmendinger, T.; Benelli, G.; Gan, K. K.; Honscheid, K.; Hufnagel, D.; Jackson, P. D.; Kagan, H.; Kass, R.; Rahimi, A. M.; Ter-Antonyan, R.; Wong, Q. K.; Blount, N. L.; Brau, J.; Frey, R.; Igonkina, O.; Lu, M.; Potter, C. T.; Rahmat, R.; Sinev, N. B.; Strom, D.; Strube, J.; Torrence, E.; Galeazzi, F.; Gaz, A.; Margoni, M.; Morandin, M.; Pompili, A.; Posocco, M.; Rotondo, M.; Simonetto, F.; Stroili, R.; Voci, C.; Benayoun, M.; Chauveau, J.; David, P.; Del Buono, L.; de La Vaissière, Ch.; Hamon, O.; Hartfiel, B. L.; John, M. J. J.; Malclès, J.; Ocariz, J.; Roos, L.; Therin, G.; Behera, P. K.; Gladney, L.; Panetta, J.; Biasini, M.; Covarelli, R.; Angelini, C.; Batignani, G.; Bettarini, S.; Bucci, F.; Calderini, G.; Carpinelli, M.; Cenci, R.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Marchiori, G.; Mazur, M. A.; Morganti, M.; Neri, N.; Paoloni, E.; Rizzo, G.; Walsh, J. J.; Haire, M.; Judd, D.; Wagoner, D. E.; Biesiada, J.; Danielson, N.; Elmer, P.; Lau, Y. P.; Lu, C.; Olsen, J.; Smith, A. J. S.; Telnov, A. V.; Bellini, F.; Cavoto, G.; D'Orazio, A.; Del Re, D.; di Marco, E.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Li Gioi, L.; Mazzoni, M. A.; Morganti, S.; Piredda, G.; Polci, F.; Safai Tehrani, F.; Voena, C.; Ebert, M.; Schröder, H.; Waldi, R.; Adye, T.; de Groot, N.; Franek, B.; Olaiya, E. O.; Wilson, F. F.; Aleksan, R.; Emery, S.; Gaidot, A.; Ganzhur, S. F.; Hamel de Monchenault, G.; Kozanecki, W.; Legendre, M.; Vasseur, G.; Yèche, Ch.; Zito, M.; Chen, X. R.; Liu, H.; Park, W.; Purohit, M. V.; Wilson, J. R.; Allen, M. T.; Aston, D.; Bartoldus, R.; Bechtle, P.; Berger, N.; Claus, R.; Coleman, J. P.; Convery, M. R.; Cristinziani, M.; Dingfelder, J. C.; Dorfan, J.; Dubois-Felsmann, G. P.; Dujmic, D.; Dunwoodie, W.; Field, R. C.; Glanzman, T.; Gowdy, S. J.; Graham, M. T.; Halyo, V.; Hast, C.; Hryn'Ova, T.; Innes, W. R.; Kelsey, M. H.; Kim, P.; Leith, D. W. G. S.; Li, S.; Libby, J.; Luitz, S.; Luth, V.; Lynch, H. L.; Macfarlane, D. B.; Marsiske, H.; Messner, R.; Muller, D. R.; O'Grady, C. P.; Ozcan, V. E.; Perazzo, A.; Perl, M.; Pulliam, T.; Ratcliff, B. N.; Roodman, A.; Salnikov, A. A.; Schindler, R. H.; Schwiening, J.; Snyder, A.; Stelzer, J.; Su, D.; Sullivan, M. K.; Suzuki, K.; Swain, S. K.; Thompson, J. M.; Tinslay, J. S.; Va'Vra, J.; van Bakel, N.; Weaver, M.; Weinstein, A. J. R.; Wisniewski, W. J.; Wittgen, M.; Wright, D. H.; Yarritu, A. K.; Yi, K.; Young, C. C.; Burchat, P. R.; Edwards, A. J.; Majewski, S. A.; Petersen, B. A.; Roat, C.; Wilden, L.; Ahmed, S.; Alam, M. S.; Bula, R.; Ernst, J. A.; Jain, V.; Pan, B.; Saeed, M. A.; Wappler, F. R.; Zain, S. B.; Bugg, W.; Krishnamurthy, M.; Spanier, S. M.; Eckmann, R.; Ritchie, J. L.; Satpathy, A.; Schilling, C. J.; Schwitters, R. F.; Izen, J. M.; Lou, X. C.; Ye, S.; Bianchi, F.; Gallo, F.; Gamba, D.; Bomben, M.; Bosisio, L.; Cartaro, C.; Cossutti, F.; Della Ricca, G.; Dittongo, S.; Lanceri, L.; Vitale, L.; Azzolini, V.; Martinez-Vidal, F.; Banerjee, Sw.; Bhuyan, B.; Brown, C. M.; Fortin, D.; Hamano, K.; Kowalewski, R.; Nugent, I. M.; Roney, J. M.; Sobie, R. J.; Back, J. J.; Harrison, P. F.; Latham, T. E.; Mohanty, G. B.; Pappagallo, M.; Band, H. R.; Chen, X.; Cheng, B.; Dasu, S.; Datta, M.; Flood, K. T.; Hollar, J. J.; Kutter, P. E.; Mellado, B.; Mihalyi, A.; Pan, Y.; Pierini, M.; Prepost, R.; Wu, S. L.; Yu, Z.; Neal, H.

    2006-10-01

    The photon spectrum in B→Xsγ decay, where Xs is any strange hadronic state, is studied using a data sample of 88.5×106 e+e-→Υ(4S)→BB¯ decays collected by the BABAR experiment at the Stanford Linear Accelerator Center. The partial branching fraction, ΔB(B→Xsγ)=(3.67±0.29(stat)±0.34(syst)±0.29(model))×10-4, the first moment ⟨Eγ⟩=2.288±0.025±0.017±0.015GeV, and the second moment ⟨Eγ2⟩=0.0328±0.0040±0.0023±0.0036GeV2 are measured for the photon energy range 1.9GeV1.6GeV. In addition, the direct CP asymmetry ACP(B→Xs+dγ) is measured to be -0.110±0.115(stat)±0.017(syst).

  2. Aqueous Molecular Dynamics Simulations of the M. tuberculosis Enoyl-ACP Reductase-NADH System and Its Complex with a Substrate Mimic or Diphenyl Ethers Inhibitors

    PubMed Central

    da Silva Lima, Camilo Henrique; de Alencastro, Ricardo Bicca; Kaiser, Carlos Roland; de Souza, Marcus Vinícius Nora; Rodrigues, Carlos Rangel; Albuquerque, Magaly Girão

    2015-01-01

    Molecular dynamics (MD) simulations of 12 aqueous systems of the NADH-dependent enoyl-ACP reductase from Mycobacterium tuberculosis (InhA) were carried out for up to 20–40 ns using the GROMACS 4.5 package. Simulations of the holoenzyme, holoenzyme-substrate, and 10 holoenzyme-inhibitor complexes were conducted in order to gain more insight about the secondary structure motifs of the InhA substrate-binding pocket. We monitored the lifetime of the main intermolecular interactions: hydrogen bonds and hydrophobic contacts. Our MD simulations demonstrate the importance of evaluating the conformational changes that occur close to the active site of the enzyme-cofactor complex before and after binding of the ligand and the influence of the water molecules. Moreover, the protein-inhibitor total steric (ELJ) and electrostatic (EC) interaction energies, related to Gly96 and Tyr158, are able to explain 80% of the biological response variance according to the best linear equation, pKi = 7.772 − 0.1885 × Gly96 + 0.0517 × Tyr158 (R2 = 0.80; n = 10), where interactions with Gly96, mainly electrostatic, increase the biological response, while those with Tyr158 decrease. These results will help to understand the structure-activity relationships and to design new and more potent anti-TB drugs. PMID:26457706

  3. Modulation of Medium-Chain Fatty Acid Synthesis in Synechococcus sp. PCC 7002 by Replacing FabH with a Chaetoceros Ketoacyl-ACP Synthase.

    PubMed

    Gu, Huiya; Jinkerson, Robert E; Davies, Fiona K; Sisson, Lyle A; Schneider, Philip E; Posewitz, Matthew C

    2016-01-01

    The isolation or engineering of algal cells synthesizing high levels of medium-chain fatty acids (MCFAs) is attractive to mitigate the high clouding point of longer chain fatty acids in algal based biodiesel. To develop a more informed understanding of MCFA synthesis in photosynthetic microorganisms, we isolated several algae from Great Salt Lake and screened this collection for MCFA accumulation to identify strains naturally accumulating high levels of MCFA. A diatom, Chaetoceros sp. GSL56, accumulated particularly high levels of C14 (up to 40%), with the majority of C14 fatty acids allocated in triacylglycerols. Using whole cell transcriptome sequencing and de novo assembly, putative genes encoding fatty acid synthesis enzymes were identified. Enzymes from this Chaetoceros sp. were expressed in the cyanobacterium Synechococcus sp. PCC 7002 to validate gene function and to determine whether eukaryotic enzymes putatively lacking bacterial evolutionary control mechanisms could be used to improve MCFA production in this promising production strain. Replacement of the Synechococcus 7002 native FabH with a Chaetoceros ketoacyl-ACP synthase III increased MCFA synthesis up to fivefold. The level of increase is dependent on promoter strength and culturing conditions. PMID:27303412

  4. Elucidating the structural basis of diphenyl ether derivatives as highly potent enoyl-ACP reductase inhibitors through molecular dynamics simulations and 3D-QSAR study.

    PubMed

    Kamsri, Pharit; Punkvang, Auradee; Saparpakorn, Patchareenart; Hannongbua, Supa; Irle, Stephan; Pungpo, Pornpan

    2014-07-01

    Diphenyl ether derivatives are good candidates for anti-tuberculosis agents that display a promising potency for inhibition of InhA, an essential enoyl-acyl carrier protein (ACP) reductase involved in fatty acid biosynthesis pathways in Mycobacterium tuberculosis. In this work, key structural features for the inhibition were identified by 3D-QSAR CoMSIA models, constructed based on available experimental binding properties of diphenyl ether inhibitors, and a set of four representative compounds was subjected to MD simulations of inhibitor-InhA complexes for the calculation of binding free energies. The results show that bulky groups are required for the R1 substituent on the phenyl A ring of the inhibitors to favor a hydrophobic pocket formed by residues Phe149, Met155, Pro156, Ala157, Tyr158, Pro193, Met199, Val203, Leu207, Ile215, and Leu218. Small substituents with a hydrophilic property are required at the R3 and R4 positions of the inhibitor phenyl B rings to form hydrogen bonds with the backbones of Gly96 and Met98, respectively. For the R2 substituent, small substituents with simultaneous hydrophilic or hydrophobic properties are required to favor the interaction with the pyrophosphate moiety of NAD(+) and the methyl side chain of Ala198, respectively. The reported data provide structural guidance for the design of new and potent diphenyl ether-based inhibitors with high inhibitory activities against M. tuberculosis InhA. PMID:24935113

  5. Resistance of Spiroplasma citri Lines to the Virus SVTS2 Is Associated with Integration of Viral DNA Sequences into Host Chromosomal and Extrachromosomal DNA

    PubMed Central

    Sha, Y.; Melcher, U.; Davis, R. E.; Fletcher, J.

    1995-01-01

    Spiroplasmavirus SVTS2, isolated from Spiroplasma melliferum TS2, produces plaques when inoculated onto lawns of Spiroplasma citri M200H, a derivative of the type strain Maroc R8A2. S. citri strains MR2 and MR3, originally selected as colonies growing within plaques on a lawn of M200H inoculated with SVTS2, were resistant to SVTS2. Genomic DNA fingerprints and electrophoretic protein profiles of M200H, MR2, and MR3 were similar, but three proteins present in M200H were missing or significantly reduced in both resistant lines. None of these three polypeptides reacted with antiserum against S. citri membrane proteins, indicating that they probably are not surface-located virus receptors. Electroporation with SVTS2 DNA produced 1.5 x 10(sup5) transfectants per (mu)g of DNA in M200H but none in MR2 or MR3, suggesting that resistance may result from inhibition of viral replication. The digestion patterns of the extrachromosomal double-stranded (ds) DNA of these lines were similar. Three TaqI fragments of MR2 extrachromosomal DNA that were not present in M200H extrachromosomal DNA hybridized strongly to an SVTS2 probe, and two of these fragments plus an additional one hybridized with the MR3 extrachromosomal DNA, indicating that a fragment of SVTS2 DNA was present in the extrachromosomal ds DNA of MR2 and MR3 but not of M200H. When the restricted genomes of all three lines were probed with SVTS2 DNA, strong hybridization to two EcoRI fragments of chromosomal MR2 and MR3 DNA but not M200H DNA indicated that SVTS2 DNA had integrated into the genomes of MR2 and MR3 but not of M200H. When MR3 extrachromosomal ds DNA containing a 2.1-kb SVTS2 DNA fragment was transfected into M200H, the transformed spiroplasmas were resistant to SVTS2. These results suggest that SVTS2 DNA fragments, possibly integrated into the chromosomal or extrachromosomal DNA of a previously susceptible spiroplasma, may function as viral incompatibility elements, providing resistance to superinfection by

  6. Xanthan Gum Removal for 1H-NMR Analysis of the Intracellular Metabolome of the Bacteria Xanthomonas axonopodis pv. citri 306.

    PubMed

    Pegos, Vanessa R; Canevarolo, Rafael R; Sampaio, Aline P; Balan, Andrea; Zeri, Ana C M

    2014-01-01

    Xanthomonas is a genus of phytopathogenic bacteria, which produces a slimy, polysaccharide matrix known as xanthan gum, which involves, protects and helps the bacteria during host colonization. Although broadly used as a stabilizer and thickener in the cosmetic and food industries, xanthan gum can be a troubling artifact in molecular investigations due to its rheological properties. In particular, a cross-reaction between reference compounds and the xanthan gum could compromise metabolic quantification by NMR spectroscopy. Aiming at an efficient gum extraction protocol, for a 1H-NMR-based metabolic profiling study of Xanthomonas, we tested four different interventions on the broadly used methanol-chloroform extraction protocol for the intracellular metabolic contents observation. Lower limits for bacterial pellet volumes for extraction were also probed, and a strategy is illustrated with an initial analysis of X. citri's metabolism by 1H-NMR spectroscopy. PMID:24957023

  7. Biological and life table parameters of Typhlodromus laurentii and Iphiseius degenerans (Acari, Phytoseiidae) fed on Panonychus citri and pollen of Oxalis pes-caprae under laboratory conditions.

    PubMed

    Tsolakis, Haralabos; Principato, Dennj; Jordà Palomero, Raoul; Lombardo, Alberto

    2016-10-01

    Typhlodromus laurentii and Iphiseius degenerans are two generalist phytoseiid mites, broadly spread in the Mediterranean area, especially in citrus orchards. In the present work we report results on various biological and life table parameters of the two phytoseiids, fed on pollen of Oxalis pes-caprae and various stages of the tetranychid Panonychus citri. Iphiseius degenerans had the shortest post embryonic development (6.53 days), the highest oviposition rate (1.83 eggs/female/day) and the shortest mean time between eggs laid (0.55 day) on Oxalis pollen, whereas the two food types did not influence these parameters in T. laurentii. However, Oxalis pollen showed a positive effect on the survivorship of the latter phytoseiid, with a median life time (LT50) of 44.51 days, which was two times longer than that registered on prey with the same phytoseiid, and on both food types with I. degenerans. This latter species had a better performance on the pollen (rm = 0.243, λ = 1.275, Ro = 22.88, DT = 2.85) than on prey (rm = 0.182, λ = 1.199, Ro = 17.43, DT = 3.81). On the other hand, the pollen influenced the net reproductive rate (25.43 females/female) of T. laurentii positively but showed the same effect as the prey on the other demographic parameters. Our results improve knowledge on the feeding behaviour of the above mentioned phytoseiids on two food sources that could represent the main possibility to maintain a consistent population of these predators during winter. Moreover, both phytoseiids were shown to be good biocontrol candidates of P. citri populations. PMID:27497592

  8. Cloning and functional expression of a cDNA encoding stearoyl-ACP Δ9-desaturase from the endosperm of coconut (Cocos nucifera L.).

    PubMed

    Gao, Lingchao; Sun, Ruhao; Liang, Yuanxue; Zhang, Mengdan; Zheng, Yusheng; Li, Dongdong

    2014-10-01

    Coconut (Cocos nucifera L.) is an economically tropical fruit tree with special fatty acid compositions. The stearoyl-acyl carrier protein (ACP) desaturase (SAD) plays a key role in the properties of the majority of cellular glycerolipids. In this paper, a full-length cDNA of a stearoyl-acyl carrier protein desaturase, designated CocoFAD, was isolated from cDNA library prepared from the endosperm of coconut (C. nucifera L.). An 1176 bp cDNA from overlapped PCR products containing ORF encoding a 391-amino acid (aa) protein was obtained. The coded protein was virtually identical and shared the homology to other Δ9-desaturase plant sequences (greater than 80% as similarity to that of Elaeis guineensis Jacq). The real-time fluorescent quantitative PCR result indicated that the yield of CocoFAD was the highest in the endosperm of 8-month-old coconut and leaf, and the yield was reduced to 50% of the highest level in the endosperm of 15-month-old coconut. The coding region showed heterologous expression in strain INVSc1 of yeast (Saccharomyces cerevisiae). GC-MS analysis showed that the levels of palmitoleic acid (16:1) and oleic acid (18:1) were improved significantly; meanwhile stearic acid (18:0) was reduced. These results indicated that the plastidial Δ9 desaturase from the endosperm of coconut was involved in the biosynthesis of hexadecenoic acid and octadecenoic acid, which was similar with other plants. These results may be valuable for understanding the mechanism of fatty acid metabolism and the genetic improvement of CocoFAD gene in palm plants in the future. PMID:25038276

  9. Molecular basis for the inhibition of β-hydroxyacyl-ACP dehydratase HadAB complex from Mycobacterium tuberculosis by flavonoid inhibitors.

    PubMed

    Dong, Yu; Qiu, Xiaodi; Shaw, Neil; Xu, Yueyang; Sun, Yuna; Li, Xuemei; Li, Jun; Rao, Zihe

    2015-07-01

    Dehydration is one of the key steps in the biosynthesis of mycolic acids and is vital to the growth of Mycobacterium tuberculosis (Mtb). Consequently, stalling dehydration cures tuberculosis (TB). Clinically used anti-TB drugs like thiacetazone (TAC) and isoxyl (ISO) as well as flavonoids inhibit the enzyme activity of the β-hydroxyacyl-ACP dehydratase HadAB complex. How this inhibition is exerted, has remained an enigma for years. Here, we describe the first crystal structures of the MtbHadAB complex bound with flavonoid inhibitor butein, 2',4,4'-trihydroxychalcone or fisetin. Despite sharing no sequence identity from Blast, HadA and HadB adopt a very similar hotdog fold. HadA forms a tight dimer with HadB in which the proteins are sitting side-by-side, but are oriented anti-parallel. While HadB contributes the catalytically critical His-Asp dyad, HadA binds the fatty acid substrate in a long channel. The atypical double hotdog fold with a single active site formed by MtbHadAB gives rise to a long, narrow cavity that vertically traverses the fatty acid binding channel. At the base of this cavity lies Cys61, which upon mutation to Ser confers drug-resistance in TB patients. We show that inhibitors bind in this cavity and protrude into the substrate binding channel. Thus, inhibitors of MtbHadAB exert their effect by occluding substrate from the active site. The unveiling of this mechanism of inhibition paves the way for accelerating development of next generation of anti-TB drugs. PMID:26081470

  10. All five host-range variants of Xanthomonas citri carry one pthA homolog with 17.5 repeats that determines pathogenicity on citrus, but none determine host-range variation.

    PubMed

    Al-Saadi, Abdulwahid; Reddy, Joseph D; Duan, Yong P; Brunings, Asha M; Yuan, Qiaoping; Gabriel, Dean W

    2007-08-01

    Citrus canker disease is caused by five groups of Xanthomonas citri strains that are distinguished primarily by host range: three from Asia (A, A*, and A(w)) and two that form a phylogenetically distinct clade and originated in South America (B and C). Every X. citri strain carries multiple DNA fragments that hybridize with pthA, which is essential for the pathogenicity of wide-host-range X. citri group A strain 3213. DNA fragments that hybridized with pthA were cloned from a representative strain from all five groups. Each strain carried one and only one pthA homolog that functionally complemented a knockout mutation of pthA in 3213. Every complementing homolog was of identical size to pthA and carried 17.5 nearly identical, direct tandem repeats, including three new genes from narrow-host-range groups C (pthC), A(w) (pthAW), and A* (pthA*). Every noncomplementing paralog was of a different size; one of these was sequenced from group A* (pthA*-2) and was found to have an intact promoter and full-length reading frame but with 15.5 repeats. None of the complementing homologs nor any of the noncomplementing paralogs conferred avirulence to 3213 on grapefruit or suppressed avirulence of a group A* strain on grapefruit. A knockout mutation of pthC in a group C strain resulted in loss of pathogenicity on lime, but the strain was unaffected in ability to elicit an HR on grapefruit. This pthC- mutant was fully complemented by pthA, pthB, or pthC. Analysis of the predicted amino-acid sequences of all functional pthA homologs and nonfunctional paralogs indicated that the specific sequence of the 17th repeat may be essential for pathogenicity of X. citri on citrus. PMID:17722697

  11. ACP Best Practice No 164

    PubMed Central

    Parsons, M; Start, R

    2001-01-01

    Much important information can be obtained at necropsy by the pathological examination of the eye and its adnexal structures in adults and children. This information may be related to the cause of death (for example, violent shaking trauma in physical child abuse), or may pertain to disease processes affecting the eye, the orbit, and surrounding structures outside the orbit. This article reviews the technical methods used to remove the following: the vitreous (for example, for biochemistry); the eye itself (anterior approach); the eye and orbital contents (posterior approach); the eye, orbit and orbital walls; and the eye, orbital walls, and surrounding structures. The removal of the eye and adnexal ocular structures must be recognised as a "culturally sensitive" issue, which must be approached cautiously. It should only be undertaken for sound scientific reasons, with the fully informed consent of the relatives and/or the coroner (or equivalent authority), and with properly agreed procedures for the eventual retention or disposal of the ocular tissues. For this reason, this article reviews not only the scientific indications and methods for the removal of such tissues, but also the legal and ethical issues that must underpin this pathology "best practice". Key Words: necropsy • ophthalamic pathology • enucleation PMID:11376013

  12. ACP Best Practice No 167

    PubMed Central

    Graham, J; Galloway, A

    2001-01-01

    Urinary tract infection is common, and it is not surprising that urine specimens make up a large proportion of those samples submitted to the routine diagnostic laboratory. Many of these specimens will show no evidence of infection and several methods can be used to screen out negative samples. Those that grow bacteria need to be carefully assessed to quantify the degree of bacteriuria and hence clinical relevance. To influence treatment, a final report should be produced within 24 hours of specimen receipt, with turnaround times continuously monitored. Much work needs to be done to determine the cost effectiveness involved in processing urine specimens and the evidence base for the final report provided. Key Words: laboratory diagnosis • urinary tract infection PMID:11729209

  13. Three-dimensional (3D) structure prediction of the American and African oil-palms β-ketoacyl-[ACP] synthase-II protein by comparative modelling

    PubMed Central

    Wang, Edina; Chinni, Suresh; Bhore, Subhash Janardhan

    2014-01-01

    Background: The fatty-acid profile of the vegetable oils determines its properties and nutritional value. Palm-oil obtained from the African oil-palm [Elaeis guineensis Jacq. (Tenera)] contains 44% palmitic acid (C16:0), but, palm-oil obtained from the American oilpalm [Elaeis oleifera] contains only 25% C16:0. In part, the b-ketoacyl-[ACP] synthase II (KASII) [EC: 2.3.1.179] protein is responsible for the high level of C16:0 in palm-oil derived from the African oil-palm. To understand more about E. guineensis KASII (EgKASII) and E. oleifera KASII (EoKASII) proteins, it is essential to know its structures. Hence, this study was undertaken. Objective: The objective of this study was to predict three-dimensional (3D) structure of EgKASII and EoKASII proteins using molecular modelling tools. Materials and Methods: The amino-acid sequences for KASII proteins were retrieved from the protein database of National Center for Biotechnology Information (NCBI), USA. The 3D structures were predicted for both proteins using homology modelling and ab-initio technique approach of protein structure prediction. The molecular dynamics (MD) simulation was performed to refine the predicted structures. The predicted structure models were evaluated and root mean square deviation (RMSD) and root mean square fluctuation (RMSF) values were calculated. Results: The homology modelling showed that EgKASII and EoKASII proteins are 78% and 74% similar with Streptococcus pneumonia KASII and Brucella melitensis KASII, respectively. The EgKASII and EoKASII structures predicted by using ab-initio technique approach shows 6% and 9% deviation to its structures predicted by homology modelling, respectively. The structure refinement and validation confirmed that the predicted structures are accurate. Conclusion: The 3D structures for EgKASII and EoKASII proteins were predicted. However, further research is essential to understand the interaction of EgKASII and EoKASII proteins with its substrates. PMID

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

    PubMed

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

    2016-06-01

    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 (< 2mM). The concentrations of ATP, ADP, and AMP were 16, 31, and 3 µ mole/Kg fwt, respectively. GTP, GMP. NAD, FMN, FAD, and riboflavin were found at concentrations below (3 µ mole/Kg fwt). The phloem was rich in nomilin 124 mM and limonin 176 µ mole/Kg fwt. Hesperidin, vicenin-2, sinensetin, and nobiletin were the most predominant flavonoids. In addition, several hydroxycinnamates were detected. The results of this study will increase our knowledge about the nature and the chemical composition of citrus phloem sap. PMID:27171979

  15. Effect of yeast cell product (CitriStim) supplementation on turkey performance and intestinal immune cell parameters during an experimental lipopolysaccharide injection.

    PubMed

    Shanmugasundaram, Revathi; Sifri, Mamduh; Jeyabalan, Ramesh; Selvaraj, Ramesh K

    2014-11-01

    An experiment was conducted to identify the effect of whole yeast cell product supplementation in turkeys following an experimental inflammatory challenge. A total of 105 one-day-old turkey tom poults were fed basal diets supplemented with 0, 0.1, and 0.2% whole yeast cell product (CitriStim, ADM, Quincy, IL). At 6 wk of age and 16 wk of age, turkeys were injected with lipopolysaccharide (LPS) at 0 or 0.25 mg/kg of BW in a 3 × 2 factorial arrangement. BW gain (P = 0.31) and feed conversion ratio (P = 0.53; 3.13, 2.94, and 2.98 for the 0, 0.10, and 0.20% CitriStim treatments, respectively) at 15 wk of age were not significantly affected by the treatment diets. Yeast cell wall product supplementation had no effect on growth in control-injected turkeys but decreased growth in LPS-injected turkeys (yeast × LPS, P < 0.05). Splenic macrophages from birds fed whole yeast cell product and injected with LPS produced higher (P < 0.01) nitric oxide than the control group injected with LPS at both 6 and 16 wk of age. At 6 and 16 wk of age, birds injected with LPS (P < 0.01; P < 0.01) and supplemented with whole yeast cell product (P = 0.05; P = 0.10) showed increased IL-1 mRNA amounts in cecal tonsils. In birds not injected with LPS, whole yeast cell supplementation increased regulatory T cell percentage and IL-10 mRNA amounts, whereas in birds injected with LPS, whole yeast cell supplementation decreased IL-10 mRNA amounts at both 6 (P < 0.01) and 16 wk (P = 0.01) of age in cecal tonsils. Whole yeast cell product supplementation increased Lactobacillus (P < 0.01 and P = 0.01) and Bifidobacteria (P < 0.01 and P = 0.01) population at 6 and 16 wk of age. In conclusion, the effect of feeding whole yeast cell product on turkeys was dependent on the inflammatory status of the bird. PMID:25239535

  16. P450's identification in two economically important psyllids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama and the potato psyllid Bactericera cockerelli (Sulc) are important vectors which spread bacterial agents causing Huanglongbing of citrus and Zebra Chip of Potato, respectively. These two diseases and vectors are recent invasive pests which continue...

  17. Transmission efficiency of Candidatus Liberibacter asiaticus and progression of Huanglongbing disease in graft- and psyllid-inoculated citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Candidatus Liberibacter asiaticus (Las) is a phloem-limited bacterium associated with Huanglongbing (HLB), one of the most destructive diseases of citrus in Florida and other citrus-producing countries. Natural transmission of Las occurs by the psyllid vector Diaphorina citri, but transmission can a...

  18. Trailers transporting oranges to processing plants move Asian citrus psyllids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (citrus greening) is one of the most serious of citrus diseases. Movement of the disease occurs as a result of natural vector-borne infection and by movement of plant material. We demonstrate here that Diaphorina citri Kuwayama (vector of citrus greening pathogens) can be transported i...

  19. Emerging psyllid genomics: Applications to reduce plant disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri, and the potato psyllid, Bactericera cockerelli, both transmit bacterial pathogens that destroy important food crops, potato, tomato, citrus, and others. The International psyllid genome consortium (being led by the authors) has developed a research team to...

  20. Broad sprectrum potential of Isaria fumosorosea on insect pests of citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Use of entomopathogenic fungi, Isaria fumosorosea, Ifr, =Paecilomyces fumosoroseus, successfully increased insect pest mortality. Spraying the Ifr containing product, PFR97 TM, on citrus seedlings was used to screen efficacy for the management of Asian citrus psyllid, Diaphorina citri; glassy-winge...