scholarly journals First Evidence of Feeding-Induced RNAi in Banana Weevil via Exogenous Application of dsRNA

Insects ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 40
Author(s):  
Henry Shaykins Mwaka ◽  
Olivier Christiaens ◽  
Priver Namanya Bwesigye ◽  
Jerome Kubiriba ◽  
Wilberforce Kateera Tushemereirwe ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Artificial Diet ◽  
Target Genes ◽  
Pupal Stage ◽  
Current Control ◽  
Control Measures ◽  
Banana Weevil ◽  
Water Control ◽  
Environmentally Sound ◽  
Species Specific

Banana weevil (Cosmopolites sordidus) is the most devastating pest of banana and plantain worldwide, yet current control measures are neither effective, sustainable, nor environmentally sound, and no resistant farmer-preferred cultivars are known to date. In this paper, we examined the ability to induce RNA interference (RNAi) in the banana weevil via feeding. We first developed an agar- and banana corm (rhizome) flour-based artificial diet in a multi-well plate setup that allowed the banana weevils to complete their life cycle from egg through the larval instars to the pupal stage in an average period of 53 days. Adults emerged about 20 days later. The artificial diet allowed the tunneling and burrowing habits of the larvae and successful metamorphosis up to adult eclosion. Adding dsRNA for laccase2 to the artificial diet resulted in albino phenotypes, confirming gene-silencing. Finally, C. sordidus was fed with dsRNA against a selection of essential target genes: snf7, rps13, mad1, vha-a, vha-d, and lgl for a period of 45 days. 100% mortality within 9–16 days was realized with dssnf7, dsrps13, and dsmad1 at 200 ng/mL artificial diet, and this corresponded to a strong reduction in gene expression. Feeding the dsRNA targeting the two vha genes resulted in 100% mortality after about 3–4 weeks, while treatment with dslgl resulted in no mortality above the dsgfp-control and the water-control. Our results have implications for the development of RNAi approaches for managing important crop pests, in that banana weevils can be controlled based on the silencing of essential target genes as snf7, rps13, and mad1. They also highlight the need for research into the development of RNAi for banana protection, eventually the engineering of host-induced gene-silencing (HIGS) cultivars, given the high RNAi efficacy and its species-specific mode of action, adding the RNAi approach to the armory of integrated pest management (IPM).

scholarly journals Crowdsourced Identification of Potential Target Genes for CTV Induced Gene Silencing for Controlling the Citrus Greening Vector Diaphorina citri

2021 ◽  
Vol 12 ◽  
Author(s):  
John E. Ramos ◽  
Ritesh G. Jain ◽  
Charles A. Powell ◽  
William O. Dawson ◽  
Siddarame Gowda ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Artificial Diet ◽  
Target Genes ◽  
Chain Complex ◽  
Heme Iron ◽  
Citrus Greening ◽  
Diaphorina Citri ◽  
Virus Induced Gene Silencing ◽  
Iron Sulfur Cluster ◽  
Citrus Production

Citrus Greening or Huanglongbing (HLB) is a disease of citrus, causing high reduction in citrus production and is transmitted by the Asian citrus psyllid Diaphorina citri Kuwayama vectoring a phloem-limited bacterium Candidatus Liberibacter sp. We report research results using crowdsourcing challenge strategy identifying potential gene targets in D. citri to control the insect using RNA interference (RNAi). From 63 submitted sequences, 43 were selected and tested by feeding them to D. citri using artificial diet assays. After feeding on artificial diet, the three most effective dsRNAs causing 30% mortality above control silenced genes expressing iron-sulfur cluster subunit of the mitochondrial electron transport chain complex (Rieske), heme iron-binding terminal oxidase enzyme (Cytochrome P450) and tetrahydrobiopterin (BH4) pathway enzyme (Pterin 4α-Carbinolamine Dehydratase). These sequences were cloned into a citrus phloem-limited virus (Citrus tristeza virus, CTV T36) expressing dsRNA against these target genes in citrus. The use of a viral mediated “para-transgenic” citrus plant system caused higher mortality to adult D. citri than what was observed using artificial diet, reaching 100% when detached citrus leaves with the engineered CTV expressing dsRNA were fed to adult D. citri. Using this approach, a virus-induced gene silencing (VIGS) can be used to test future transgenic cultivars before genetically engineering citrus. RNA Seq analysis after feeding D. citri CTV-RIE on infected leaves identified transcriptionally modified genes located upstream and downstream of the targeted RIE gene. These genes were annotated showing that many are associated with the primary function of the Rieske gene that was targeted by VIGS.

Water Quality in the Priority Watercourses of Hong Kong in Respect of Various Environmental Control Measures

1991 ◽  
Vol 23 (1-3) ◽  
pp. 85-91 ◽  
Author(s):  
Ho Kin-chung
Keyword(s):  
Water Quality ◽  
Hong Kong ◽  
Environmental Control ◽  
Control Measures ◽  
Livestock Waste ◽  
Water Control ◽  
Control Zone ◽  
Town Development ◽  
Control Scheme ◽  
Term Monitoring

The water quality in the 12 priority watercourses of Hong Kong was appraised in respect of the various environmental control measures being undertaken. It was noted that water quality in Lam Tsuen River had been significantly improved since 1983. This is attributed to recent resumption of unsewered lands for town development, training of river basin to increase flow, and declaration of the catchment as a “Water Control Zone” under the Water Pollution Control Ordinance. In contrast with the other heavily polluted watercourses to which little abatement measures were implemented, the water qualities of Shing Mun River and Tuen Mun River were slightly upgraded because of the efforts to rectify unauthorized industrial discharges back to foul sewer and provision of interceptors and sewers to villages. The 10 year Livestock Waste Control Scheme enforced on 24 June 1989 was found in parallel with BOD and suspended solids decrease in watercourses. To assess its effectiveness, however, a longer term monitoring is required to get a conclusive result.

Artificial microRNA (amiRNA) induced gene silencing in alfalfa (Medicago sativa)

Botany ◽  
2013 ◽  
Vol 91 (2) ◽  
pp. 117-122 ◽  
Author(s):  
Julian C. Verdonk ◽  
Michael L. Sullivan
Keyword(s):  
Gene Silencing ◽  
Medicago Sativa ◽  
Target Gene ◽  
Target Genes ◽  
Mirna Precursor ◽  
Crop Species ◽  
Forage Crop ◽  
Ribonucleic Acids ◽  
Endogenous Gene ◽  
Medicago Sativa L

Gene silencing is a powerful technique that allows the study of the function of specific genes by selectively reducing their transcription. Several different approaches can be used, however they all have in common the artificial generation of single stranded small ribonucleic acids (RNAs) that are utilized by the endogenous gene silencing machinery of the organism. Artificial microRNAs (amiRNA) can be used to very specifically target genes for silencing because only a short sequence of 21 nucleotides of the gene of interest is used. Gene silencing via amiRNA has been developed for Arabidopsis thaliana (L.) Heynh. and rice using endogenous microRNA (miRNA) precursors and has been shown to also work effectively in other dicot species using the arabidopsis miRNA precursor. Here, we demonstrate that the arabidopsis miR319 precursor can be used to silence genes in the important forage crop species alfalfa (Medicago sativa L.) by silencing the expression of a transgenic beta-glucuronidase (GUSPlus) target gene.

scholarly journals Phylogenetic Complexity of Morphologically Identified Anopheles squamosus in Southern Zambia

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 146
Author(s):  
Jordan Hoffman ◽  
Ilinca Ciubotariu ◽  
Limonty Simubali ◽  
Twig Mudenda ◽  
William Moss ◽  
...  
Keyword(s):  
Phylogenetic Relationships ◽  
Catchment Area ◽  
Control Strategies ◽  
Light Trap ◽  
Current Control ◽  
Control Measures ◽  
Morphological Identification ◽  
The Past ◽  
Blood Meal Source ◽  
Residual Malaria Transmission

Despite dramatic reductions in malaria cases in the catchment area of Macha Hospital, Choma District, Southern Province in Zambia, prevalence has remained near 1–2% by RDT for the past several years. To investigate residual malaria transmission in the area, this study focuses on the relative abundance, foraging behavior, and phylogenetic relationships of Anopheles squamosus specimens. In 2011, higher than expected rates of anthropophily were observed among “zoophilic” An. squamosus, a species that had sporadically been found to contain Plasmodium falciparum sporozoites. The importance of An. squamosus in the region was reaffirmed in 2016 when P. falciparum sporozoites were detected in numerous An. squamosus specimens. This study analyzed Centers for Disease Control (CDC) light trap collections of adult mosquitoes from two collection schemes: one performed as part of a reactive-test-and-treat program and the second performed along a geographical transect. Morphological identification, molecular verification of anopheline species, and blood meal source were determined on individual samples. Data from these collections supported earlier studies demonstrating An. squamosus to be primarily exophagic and zoophilic, allowing them to evade current control measures. The phylogenetic relationships generated from the specimens in this study illustrate the existence of well supported clade structure among An. squamosus specimens, which further emphasizes the importance of molecular identification of vectors. The primarily exophagic behavior of An. squamosus in these collections also highlights that indoor vector control strategies will not be sufficient for elimination of malaria in southern Zambia.

scholarly journals Timing and Route of Contamination of Patient Rooms With Healthcare-Associated Pathogens

2020 ◽  
Vol 41 (S1) ◽  
pp. s412-s412
Author(s):  
Sarah Redmond ◽  
Jennifer Cadnum ◽  
Basya Pearlmutter ◽  
Natalia Pinto Herrera ◽  
Curtis Donskey
Keyword(s):  
Acute Care Hospital ◽  
Current Control ◽  
Pathogen Transmission ◽  
Control Measures ◽  
Effective Control ◽  
Portable Devices ◽  
Care Hospital ◽  
Spa Typing ◽  
Persistent Problem ◽  
Healthcare Associated

Background: Transmission of healthcare-associated pathogens such as Clostridioides difficile and methicillin-resistant Staphylococcus aureus (MRSA) is a persistent problem in healthcare facilities despite current control measures. A better understanding of the routes of pathogen transmission is needed to develop effective control measures. Methods: We conducted an observational cohort study in an acute-care hospital to identify the timing and route of transfer of pathogens to rooms of newly admitted patients with negative MRSA nares results and no known carriage of other healthcare-associated pathogens. Rooms were thoroughly cleaned and disinfected prior to patient admission. Interactions of patients with personnel and portable equipment were observed, and serial cultures for pathogens were collected from the skin of patients and from surfaces, including those observed to come in contact with personnel and equipment. For MRSA, spa typing was used to determine relatedness of patient and environmental isolates. Results: For the 17 patients enrolled, 1 or more environmental cultures became positive for MRSA in rooms of 10 patients (59%), for C. difficile in rooms of 2 patients (12%) and for vancomycin-resistant enterococci (VRE) in rooms of 2 patients (12%). The patients interacted with an average of 2.4 personnel and 0.6 portable devices per hour of observation. As shown in Figure 1, MRSA contamination of the floor occurred rapidly as personnel entered the room. In a subset of patients, MRSA was subsequently recovered from patients’ socks and bedding and ultimately from the high-touch surfaces in the room (tray table, call button, bedrail). For several patients, MRSA isolates recovered from the floor had the same spa type as isolates subsequently recovered from other sites (eg, socks, bedding, and/or high touch surfaces). The direct transfer of healthcare-associated pathogens from personnel or equipment to high-touch surfaces was not detected. Conclusions: Healthcare-associated pathogens rapidly accumulate on the floor of patient rooms and can be transferred to the socks and bedding of patients and to high-touch surfaces. Healthcare facility floors may be an underappreciated source of pathogen dissemination not addressed by current infection control measures.Funding: NoneDisclosures: None

scholarly journals Simultaneous silencing of two different Arabidopsis genes with a novel virus-induced gene silencing vector

Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Kunxin Wu ◽  
Yadan Wu ◽  
Chunwei Zhang ◽  
Yan Fu ◽  
Zhixin Liu ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Double Mutant ◽  
Target Genes ◽  
Rna Binding ◽  
Protein Product ◽  
Antiviral Defense ◽  
Virus Induced Gene Silencing ◽  
Argonaute 2 ◽  
Plant Genes ◽  
Silencing Pathways

Abstract Background Virus-induced gene silencing (VIGS) is a useful tool for functional characterizations of plant genes. However, the penetrance of VIGS varies depending on the genes to be silenced, and has to be evaluated by examining the transcript levels of target genes. Results In this report, we report the development of a novel VIGS vector that permits a preliminary assessment of the silencing penetrance. This new vector is based on an attenuated variant of Turnip crinkle virus (TCV) known as CPB that can be readily used in Arabidopsis thaliana to interrogate genes of this model plant. A CPB derivative, designated CPB1B, was produced by inserting a 46 nucleotide section of the Arabidopsis PHYTOENE DESATURASE (PDS) gene into CPB, in antisense orientation. CPB1B induced robust PDS silencing, causing easily visible photobleaching in systemically infected Arabidopsis leaves. More importantly, CPB1B can accommodate additional inserts, derived from other Arabidopsis genes, causing the silencing of two or more genes simultaneously. With photobleaching as a visual marker, we adopted the CPB1B vector to validate the involvement of DICER-LIKE 4 (DCL4) in antiviral defense against TCV. We further revealed the involvement of ARGONAUTE 2 (AGO2) in PDS silencing and antiviral defense against TCV in dcl2drb4 double mutant plants. These results demonstrated that DOUBLE-STRANDED RNA-BINDING PROTEIN 4 (DRB4), whose protein product (DRB4) commonly partners with DCL4 in the antiviral silencing pathway, was dispensable for PDS silencing induced by CPB1B derivative in dcl2drb4 double mutant plants. Conclusions The CPB1B-based vector developed in this work is a valuable tool with visualizable indicator of the silencing penetrance for interrogating Arabidopsis genes, especially those involved in the RNA silencing pathways.

Hydrologic Performance of Bioretention Storm-Water Control Measures

2012 ◽  
Vol 17 (5) ◽  
pp. 604-614 ◽  
Author(s):  
Allen P. Davis ◽  
Robert G. Traver ◽  
William F. Hunt ◽  
Ryan Lee ◽  
Robert A. Brown ◽  
...  
Keyword(s):  
Control Measures ◽  
Storm Water ◽  
Water Control ◽  
Hydrologic Performance

scholarly journals Hydrologic Modelling of Construction Site Sediment Control Pond Using SWMM

2021 ◽  
Author(s):  
Renata Krasnova
Keyword(s):  
Stormwater Management ◽  
Current Control ◽  
Control Measures ◽  
Background Information ◽  
Construction Site ◽  
Stormwater Treatment ◽  
Hydrologic Modelling ◽  
Sediment Control ◽  
Sources Of Pollution ◽  
Receiving Waters

Construction activities have been identified as one of the major sources of pollution to receiving waters. Although Erosion and Sediment Control (ESC) measures reduce the amount of sediment exported from construction sites, there are still significant concerns regarding the sufficiency of current control measures to protect receiving waters. This study documents the work completed to monitor and model the performance of a typical stormwater management facility used for erosion and sediment control in suburban construction site. The main objective of this study is to provide background information regarding the performance of stormwater management facilities for treating urban construction runoff prior to discharging to receiving water bodies. The RUNOFF and STORAGE TREATMENT blocks of EPA's stormwater management model (PCSWMM4.4) were used to simulate the quantity and quality of stormwater run-off from the area under construction and assess the performance of stormwater treatment facility (Ballymore Pond) located in Richmond Hill, Ontario. The performance of the construction site sediment control pond was found to be unsatisfactory due to the high outflow concentration of suspended solids. Some specific recommendations to improve its effectiveness have been made.

scholarly journals Hydrologic Modelling of Construction Site Sediment Control Pond Using SWMM

2021 ◽  
Author(s):  
Renata Krasnova
Keyword(s):  
Stormwater Management ◽  
Current Control ◽  
Control Measures ◽  
Background Information ◽  
Construction Site ◽  
Stormwater Treatment ◽  
Hydrologic Modelling ◽  
Sediment Control ◽  
Sources Of Pollution ◽  
Receiving Waters

Construction activities have been identified as one of the major sources of pollution to receiving waters. Although Erosion and Sediment Control (ESC) measures reduce the amount of sediment exported from construction sites, there are still significant concerns regarding the sufficiency of current control measures to protect receiving waters. This study documents the work completed to monitor and model the performance of a typical stormwater management facility used for erosion and sediment control in suburban construction site. The main objective of this study is to provide background information regarding the performance of stormwater management facilities for treating urban construction runoff prior to discharging to receiving water bodies. The RUNOFF and STORAGE TREATMENT blocks of EPA's stormwater management model (PCSWMM4.4) were used to simulate the quantity and quality of stormwater run-off from the area under construction and assess the performance of stormwater treatment facility (Ballymore Pond) located in Richmond Hill, Ontario. The performance of the construction site sediment control pond was found to be unsatisfactory due to the high outflow concentration of suspended solids. Some specific recommendations to improve its effectiveness have been made.

scholarly journals Biodiversity of Amoebae and Amoeba-Resisting Bacteria in a Hospital Water Network

2006 ◽  
Vol 72 (4) ◽  
pp. 2428-2438 ◽  
Author(s):  
Vincent Thomas ◽  
Katia Herrera-Rimann ◽  
Dominique S. Blanc ◽  
Gilbert Greub
Keyword(s):  
Legionella Pneumophila ◽  
Strong Association ◽  
Acanthamoeba Castellanii ◽  
Control Measures ◽  
Water Network ◽  
Water Control ◽  
Domestic Water ◽  
Mycobacterium Xenopi ◽  
Hartmannella Vermiformis ◽  
Human Infections

ABSTRACT Free-living amoebae (FLA) are ubiquitous organisms that have been isolated from various domestic water systems, such as cooling towers and hospital water networks. In addition to their own pathogenicity, FLA can also act as Trojan horses and be naturally infected with amoeba-resisting bacteria (ARB) that may be involved in human infections, such as pneumonia. We investigated the biodiversity of bacteria and their amoebal hosts in a hospital water network. Using amoebal enrichment on nonnutrient agar, we isolated 15 protist strains from 200 (7.5%) samples. One thermotolerant Hartmannella vermiformis isolate harbored both Legionella pneumophila and Bradyrhizobium japonicum. By using amoebal coculture with axenic Acanthamoeba castellanii as the cellular background, we recovered at least one ARB from 45.5% of the samples. Four new ARB isolates were recovered by culture, and one of these isolates was widely present in the water network. Alphaproteobacteria (such as Rhodoplanes, Methylobacterium, Bradyrhizobium, Afipia, and Bosea) were recovered from 30.5% of the samples, mycobacteria (Mycobacterium gordonae, Mycobacterium kansasii, and Mycobacterium xenopi) were recovered from 20.5% of the samples, and Gammaproteobacteria (Legionella) were recovered from 5.5% of the samples. No Chlamydia or Chlamydia-like organisms were recovered by amoebal coculture or detected by PCR. The observed strong association between the presence of amoebae and the presence of Legionella (P < 0.001) and mycobacteria (P = 0.009) further suggests that FLA are a reservoir for these ARB and underlines the importance of considering amoebae when water control measures are designed.

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