To see the other types of publications on this topic, follow the link: Molecular virology; Biological control agents.
Journal articles on the topic 'Molecular virology; Biological control agents'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Molecular virology; Biological control agents.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Abdoulaye, Assane Hamidou, Mohamed Frahat Foda, and Ioly Kotta-Loizou. "Viruses Infecting the Plant Pathogenic Fungus Rhizoctonia solani." Viruses 11, no. 12 (November 30, 2019): 1113. http://dx.doi.org/10.3390/v11121113.
Full textAbstract:
The cosmopolitan fungus Rhizoctonia solani has a wide host range and is the causal agent of numerous crop diseases, leading to significant economic losses. To date, no cultivars showing complete resistance to R. solani have been identified and it is imperative to develop a strategy to control the spread of the disease. Fungal viruses, or mycoviruses, are widespread in all major groups of fungi and next-generation sequencing (NGS) is currently the most efficient approach for their identification. An increasing number of novel mycoviruses are being reported, including double-stranded (ds) RNA, circular single-stranded (ss) DNA, negative sense (−)ssRNA, and positive sense (+)ssRNA viruses. The majority of mycovirus infections are cryptic with no obvious symptoms on the hosts; however, some mycoviruses may alter fungal host pathogenicity resulting in hypervirulence or hypovirulence and are therefore potential biological control agents that could be used to combat fungal diseases. R. solani harbors a range of dsRNA and ssRNA viruses, either belonging to established families, such as Endornaviridae, Tymoviridae, Partitiviridae, and Narnaviridae, or unclassified, and some of them have been associated with hypervirulence or hypovirulence. Here we discuss in depth the molecular features of known viruses infecting R. solani and their potential as biological control agents.
2
Jahnke, Marlene, Edward C. Holmes, Peter J. Kerr, John D. Wright, and Tanja Strive. "Evolution and Phylogeography of the Nonpathogenic Calicivirus RCV-A1 in Wild Rabbits in Australia." Journal of Virology 84, no. 23 (September 22, 2010): 12397–404. http://dx.doi.org/10.1128/jvi.00777-10.
Full textAbstract:
ABSTRACT Despite its potential importance for the biological control of European rabbits, relatively little is known about the evolution and molecular epidemiology of rabbit calicivirus Australia 1 (RCV-A1). To address this issue we undertook an extensive evolutionary analysis of 36 RCV-A1 samples collected from wild rabbit populations in southeast Australia between 2007 and 2009. Based on phylogenetic analysis of the entire capsid sequence, six clades of RCV-A1 were defined, each exhibiting strong population subdivision. Strikingly, our estimates of the time to the most recent common ancestor of RCV-A1 coincide with the introduction of rabbits to Australia in the mid-19th century. Subsequent divergence events visible in the RCV-A1 phylogenies likely reflect key moments in the history of the European rabbit in Australia, most notably the bottlenecks in rabbit populations induced by the two viral biocontrol agents used on the Australian continent, myxoma virus and rabbit hemorrhagic disease virus (RHDV). RCV-A1 strains therefore exhibit strong phylogeographic separation and may constitute a useful tool to study recent host population dynamics and migration patterns, which in turn could be used to monitor rabbit control in Australia.
3
Dumais, Nancy, Marie-Ève Paré, Simon Mercier, Salim Bounou, Susan J. Marriot, Benoit Barbeau, and Michel J. Tremblay. "T-Cell Receptor/CD28 Engagement When Combined with Prostaglandin E2 Treatment Leads to Potent Activation of Human T-Cell Leukemia Virus Type 1." Journal of Virology 77, no. 20 (October 15, 2003): 11170–79. http://dx.doi.org/10.1128/jvi.77.20.11170-11179.2003.
Full textAbstract:
ABSTRACT Infection with human T-cell leukemia virus type 1 (HTLV-1) is characterized by long latency periods, indicating that viral gene expression is under tight control. There is presently little information available regarding the nature of extracellular stimuli that can transactivate the regulatory elements of HTLV-1 (i.e., long terminal repeat [LTR]). To gain insight into the biological importance of externally induced activation pathways in virus gene expression, primary and established T cells were transfected with HTLV-1-based reporter gene vectors and then were treated with agents that cross-linked the T-cell receptor (TCR) or the costimulatory CD28 molecule with prostaglandin E2 (PGE2). We demonstrated that a potent induction of HTLV-1 LTR-driven reporter gene activity was seen only when the three agents were used in combination. Interestingly, similar observations were made when using C91/PL, a cell line that carries integrated HTLV-1 proviral DNA. This TCR-CD28-PGE2-mediated increase in virus transcription was dependent on protein kinase A activation and induction of the cAMP response element binding protein. Experiments with a mutated reporter construct further revealed the importance of the Tax-responsive elements in the HTLV-1 LTR in the observed up regulation of virus gene expression when TCR/CD28 engagement was combined with PGE2 treatment. The protein tyrosine kinases p56 lck and the transmembrane tyrosine phosphatase CD45 were all found to be involved in TCR-CD28-PGE2-directed increase in HTLV-1 LTR activity. This study presents new information on the possible mechanisms underlying reactivation of this retrovirus.
4
Song, Nan, Lihong Chen, Zhemin Zhou, Xingmei Ren, Bo Liu, Siyu Zhou, Caihong Wang, et al. "Genome-wide dissection reveals diverse pathogenic roles of bacterial Tc toxins." PLOS Pathogens 17, no. 2 (February 4, 2021): e1009102. http://dx.doi.org/10.1371/journal.ppat.1009102.
Full textAbstract:
Tc toxins were originally identified in entomopathogenic bacteria, which are important as biological pest control agents. Tc toxins are heteromeric exotoxins composed of three subunit types, TcA, TcB, and TcC. The C-terminal portion of the TcC protein encodes the actual toxic domain, which is translocated into host cells by an injectosome nanomachine comprising the other subunits. Currently the pathogenic roles and distribution of Tc toxins among different bacterial genera remain unclear. Here we have performed a comprehensive genome-wide analysis, and established a database that includes 1,608 identified Tc loci containing 2,528 TcC proteins in 1,421 Gram-negative and positive bacterial genomes. Our findings indicate that TcCs conform to the architecture of typical polymorphic toxins, with C-terminal hypervariable regions (HVR) encoding more than 100 different classes of putative toxic domains, most of which have not been previously recognized. Based on further analysis of Tc loci in the genomes of all Salmonella and Yersinia strains in EnteroBase, a “two-level” evolutionary dynamics scenario is proposed for TcC homologues. This scenario implies that the conserved TcC RHS core domain plays a critical role in the taxonomical specific distribution of TcC HVRs. This study provides an extensive resource for the future development of Tc toxins as valuable agrochemical tools. It furthermore implies that Tc proteins, which are encoded by a wide range of pathogens, represent an important versatile toxin superfamily with diverse pathogenic mechanisms.
5
Verschuere, Laurent, Geert Rombaut, Patrick Sorgeloos, and Willy Verstraete. "Probiotic Bacteria as Biological Control Agents in Aquaculture." Microbiology and Molecular Biology Reviews 64, no. 4 (December 1, 2000): 655–71. http://dx.doi.org/10.1128/mmbr.64.4.655-671.2000.
Full textAbstract:
SUMMARY There is an urgent need in aquaculture to develop microbial control strategies, since disease outbreaks are recognized as important constraints to aquaculture production and trade and since the development of antibiotic resistance has become a matter of growing concern. One of the alternatives to antimicrobials in disease control could be the use of probiotic bacteria as microbial control agents. This review describes the state of the art of probiotic research in the culture of fish, crustaceans, mollusks, and live food, with an evaluation of the results obtained so far. A new definition of probiotics, also applicable to aquatic environments, is proposed, and a detailed description is given of their possible modes of action, i.e., production of compounds that are inhibitory toward pathogens, competition with harmful microorganisms for nutrients and energy, competition with deleterious species for adhesion sites, enhancement of the immune response of the animal, improvement of water quality, and interaction with phytoplankton. A rationale is proposed for the multistep and multidisciplinary process required for the development of effective and safe probiotics for commercial application in aquaculture. Finally, directions for further research are discussed.
6
Hokkanen, Heikki M. T., and David Pimentel. "NEW ASSOCIATIONS IN BIOLOGICAL CONTROL: THEORY AND PRACTICE." Canadian Entomologist 121, no. 10 (October 1989): 829–40. http://dx.doi.org/10.4039/ent121829-10.
Full textAbstract:
AbstractThe new association approach for selecting biological control agents has been reanalyzed in the light of recent data. The results support the conclusion that the new association approach is ecologically and statistically sound. One of the major advantages of this approach is its capacity to control native pests, which make up 60–80% of all pests. The specificity of biocontrol agents newly associated with the target hosts is similar to other biocontrol agents. In addition, the new association approach is as safe as the old association approach in terms of environmental risks. Recent trials in the use of new associations have been most encouraging, and suggest that this approach should contribute to the future success of biological pest control worldwide.
7
HINOMOTO, Norihide, Shigeyuki NAGAMORI, Kazuki KAKIMOTO, Toru SHIMIZU, Tomomi HIGAKI, Masahiko MURAJI, Takashi NODA, and Kenjiro KAWASAKI. "Molecular Identification and Evaluation of Orius species (Heteroptera: Anthocoridae) as Biological Control Agents." Japan Agricultural Research Quarterly: JARQ 43, no. 4 (2009): 281–88. http://dx.doi.org/10.6090/jarq.43.281.
Full text
8
Ghisalberti, E., and K. Sivasithamparam. "The Nature of Secondary Metabolites Produced by Biological Control Agents." Planta Medica 56, no. 06 (December 1990): 641. http://dx.doi.org/10.1055/s-2006-961287.
Full text
9
Bale, J. S., J. C. van Lenteren, and F. Bigler. "Biological control and sustainable food production." Philosophical Transactions of the Royal Society B: Biological Sciences 363, no. 1492 (September 6, 2007): 761–76. http://dx.doi.org/10.1098/rstb.2007.2182.
Full textAbstract:
The use of biological control for the management of pest insects pre-dates the modern pesticide era. The first major successes in biological control occurred with exotic pests controlled by natural enemy species collected from the country or area of origin of the pest (classical control). Augmentative control has been successfully applied against a range of open-field and greenhouse pests, and conservation biological control schemes have been developed with indigenous predators and parasitoids. The cost–benefit ratio for classical biological control is highly favourable (1 : 250) and for augmentative control is similar to that of insecticides (1 : 2–1 : 5), with much lower development costs. Over the past 120 years, more than 5000 introductions of approximately 2000 non-native control agents have been made against arthropod pests in 196 countries or islands with remarkably few environmental problems. Biological control is a key component of a ‘systems approach’ to integrated pest management, to counteract insecticide-resistant pests, withdrawal of chemicals and minimize the usage of pesticides. Current studies indicate that genetically modified insect-resistant Bt crops may have no adverse effects on the activity or function of predators or parasitoids used in biological control. The introduction of rational approaches for the environmental risk assessment of non-native control agents is an essential step in the wider application of biological control, but future success is strongly dependent on a greater level of investment in research and development by governments and related organizations that are committed to a reduced reliance on chemical control.
10
Knudsen, Guy R., and Louise-Marie C. Dandurand. "Ecological Complexity and the Success of Fungal Biological Control Agents." Advances in Agriculture 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/542703.
Full textAbstract:
Fungal biological control agents against plant pathogens, especially those in soil, operate within physically, biologically, and spatially complex systems by means of a variety of trophic and nontrophic interspecific interactions. However, the biocontrol agents themselves are also subject to the same types of interactions, which may reduce or in some cases enhance their efficacy against target plant pathogens. Characterization of these ecologically complex systems is challenging, but a number of tools are available to help unravel this complexity. Several of these tools are described here, including the use of molecular biology to generate biocontrol agents with useful marker genes and then to quantify these agents in natural systems, epifluorescence and confocal laser scanning microscopy to observe their presence and activity in situ, and spatial statistics and computer simulation modeling to evaluate and predict these activities in heterogeneous soil habitats.
11
Harms, Nathan E., Ian A. Knight, Paul D. Pratt, Angelica M. Reddy, Abhishek Mukherjee, Ping Gong, Julie Coetzee, S. Raghu, and Rodrigo Diaz. "Climate Mismatch Between Introduced Biological Control Agents and Their Invasive Host Plants: Improving Biological Control of Tropical Weeds in Temperate Regions." Insects 12, no. 6 (June 12, 2021): 549. http://dx.doi.org/10.3390/insects12060549.
Full textAbstract:
Many weed biological control programs suffer from large-scale spatial variation in success due to restricted distributions or abundances of agents in temperate climates. For some of the world’s worst aquatic weeds, agents are established but overwintering conditions limit their survival in higher latitudes or elevations. The resulting need is for new or improved site- or region-specific biological control tools. Here, we review this challenge with a focus on low-temperature limitations of agents and propose a roadmap for improving success. Investigations across spatial scales, from global (e.g., foreign exploration), to local (selective breeding), to individual organisms (molecular modification), are discussed. A combination of traditional (foreign) and non-traditional (introduced range) exploration may lead to the discovery and development of better-adapted agent genotypes. A multivariate approach using ecologically relevant metrics to quantify and compare cold tolerance among agent populations is likely required. These data can be used to inform environmental niche modeling combined with mechanistic modeling of species’ fundamental climate niches and life histories to predict where, when, and at what abundance agents will occur. Finally, synthetic and systems biology approaches in conjunction with advanced modern genomics, gene silencing and gene editing technologies may be used to identify and alter the expression of genes enhancing cold tolerance, but this technology in the context of weed biological control has not been fully explored.
12
Di Francesco, Alessandra, Matteo Calassanzio, Claudio Ratti, Marta Mari, Annibale Folchi, and Elena Baraldi. "Molecular characterization of the two postharvest biological control agents Aureobasidium pullulans L1 and L8." Biological Control 123 (August 2018): 53–59. http://dx.doi.org/10.1016/j.biocontrol.2018.05.005.
Full text
13
Muller, Franck J., Peter G. Mason, Lloyd M. Dosdall, and Ulrich Kuhlmann. "European ectoparasitoids of two classical weed biological control agents released in North America." Canadian Entomologist 143, no. 2 (April 2011): 197–210. http://dx.doi.org/10.4039/n10-057.
Full textAbstract:
AbstractThe ceutorhynchine weevils Hadroplontus litura (F.) and Microplontus edentulus (Schultze) (Coleoptera: Curculionidae), are established in North America as biological control agents for Canada thistle, Cirsium arvense (L.) Scop., and scentless chamomile, Tripleurospermum perforatum (Mérat) M. Lainz (Asteraceae), respectively. In North America, both weeds occur sympatrically and in similar habitats as another ceutorhynchine, Ceutorhynchus obstrictus (Marsham) (cabbage seedpod weevil), an important pest of canola, Brassica napus L., and Brassica rapa L. (Brassicaceae). Ceutorhynchinae weevils released to control weeds in cultivated crops may serve as alternate hosts if agents released for biological control of C. obstrictus are not specific to that species. Parasitoids associated with M. edentulus and H. litura inflict similar levels of mortality on their hosts, yet a single species was associated with the latter host, whereas 13 species attacked the former. The stem-mining M. edentulus appears to be at some risk but not the root-crown feeding H. litura, should the parasitoids Trichomalus perfectus (Walker) and Mesopolobus morys (Walker) (Hymenoptera: Pteromalidae) be introduced as biological control agents of the silique-feeding C. obstrictus. These findings suggest that feeding niche may be an important criterion for developing a nontarget species test list for host-range testing of potential biological control agents.
14
Pandey, Ajita, and Mohit Sharma. "Reappraisal of trifluperidol against Nsp3 as a potential therapeutic for novel COVID-19: a molecular docking and dynamics study." Future Virology 16, no. 7 (July 2021): 491–506. http://dx.doi.org/10.2217/fvl-2020-0361.
Full textAbstract:
Novel COVID-19 is a highly infectious disease that is caused by the recently discovered SARS-CoV-2. It is a fast-spreading disease that urgently requires therapeutics. The current study employed computational regression methods to target the ADP-ribose phosphatase (ADRP) domain of Nsp3 using FDA-approved drugs. Identified leads were further investigated using molecular dynamics simulation (MDS). The screening and MDS results suggest that trifluperidol could be a novel inhibitor of the ADRP domain of Nsp3. Trifluperidol could, therefore, be used to help control the spread of COVID-19, either alone or in combination with antiviral agents.
15
Morton, Oliver, Penny Hirsch, and Brian Kerry. "Infection of plant-parasitic nematodes by nematophagous fungi – a review of the application of molecular biology to understand infection processes and to improve biological control." Nematology 6, no. 2 (2004): 161–70. http://dx.doi.org/10.1163/1568541041218004.
Full textAbstract:
AbstractEnvironmental concerns over conventional nematicides have led to increasing interest in the use of biological control agents to control plant-parasitic nematodes. The development of nematophagous fungi as biological control agents has revealed a need for further understanding of their infection processes. The egg-parasitic fungi, Pochonia chlamydosporia and Paecilomyces lilacinus, and the nematode trapping fungus, Arthrobotrys oligospora, have received the most attention. Through the application of biochemistry and molecular biology, aspects of their infection processes have been elucidated. This has involved the characterisation of enzymes that aid penetration of the eggshell or the nematode body wall and the identification of nematicidal toxins. This growing understanding of the biology of infection is opening new avenues in the improvement of fungi as biological control agents.
16
Donald, Claire, Margus Varjak, Eric Aguiar, João Marques, Vattipally Sreenu, Esther Schnettler, and Alain Kohl. "Antiviral RNA Interference Activity in Cells of the Predatory Mosquito, Toxorhynchites amboinensis." Viruses 10, no. 12 (December 6, 2018): 694. http://dx.doi.org/10.3390/v10120694.
Full textAbstract:
Arthropod vectors control the replication of arboviruses through their innate antiviral immune responses. In particular, the RNA interference (RNAi) pathways are of notable significance for the control of viral infections. Although much has been done to understand the role of RNAi in vector populations, little is known about its importance in non-vector mosquito species. In this study, we investigated the presence of an RNAi response in Toxorhynchites amboinensis, which is a non-blood feeding species proposed as a biological control agent against pest mosquitoes. Using a derived cell line (TRA-171), we demonstrate that these mosquitoes possess a functional RNAi response that is active against a mosquito-borne alphavirus, Semliki Forest virus. As observed in vector mosquito species, small RNAs are produced that target viral sequences. The size and characteristics of these small RNAs indicate that both the siRNA and piRNA pathways are induced in response to infection. Taken together, this data suggests that Tx. amboinensis are able to control viral infections in a similar way to natural arbovirus vector mosquito species. Understanding their ability to manage arboviral infections will be advantageous when assessing these and similar species as biological control agents.
17
Harris, P., and J. D. Shorthouse. "EFFECTIVENESS OF GALL INDUCERS IN WEED BIOLOGICAL CONTROL." Canadian Entomologist 128, no. 6 (December 1996): 1021–55. http://dx.doi.org/10.4039/ent1281021-6.
Full textAbstract:
AbstractGall inducers are favoured as biocontrol agents of weeds because they tend to have a narrow host range. Six insect and one nematode gall inducer used in Canada are described in terms of their biology, gall morphology, gall physiology, and effectiveness in weed control. The species differ in plant organ attacked, requirement for moisture, whether the galls are induced by secretions or by severing xylem, and effectiveness, which in part relates to the ability of the gall to import nutrients. The most powerful galls divert assimilates from other sinks via a gall’s vascular system joined to that of their host. One of our examples also has mechanisms to compensate for reduction of turgor during drought. Two of the gall inducers enhance their nutrient supply by severing xylem in a plant nutrient sink. One, in the short-term sink of a thistle capitulum, obtains about a quarter of its assimilates at the expense of other capitula. The other, in the long-term sink of a rosette root, approximately halves seed production. Hypotheses are presented to explain various aspects of gall development and function.
18
Marsico, Antonio Domenico, Matteo Velenosi, Rocco Perniola, Carlo Bergamini, Scott Sinonin, Vanessa David-Vaizant, Flavia Angela Maria Maggiolini, Alexandre Hervè, Maria Francesca Cardone, and Mario Ventura. "Native Vineyard Non-Saccharomyces Yeasts Used for Biological Control of Botrytis cinerea in Stored Table Grape." Microorganisms 9, no. 2 (February 22, 2021): 457. http://dx.doi.org/10.3390/microorganisms9020457.
Full textAbstract:
Postharvest spoilage fungi, such as Botrytis cinerea, are considered the main cause of losses of fresh fruit quality and vegetables during storage, distribution, and consumption. The current control strategy is the use of SO2 generator pads whose application is now largely under observation. A high quantity of SO2 can be deleterious for fresh fruits and vegetables and it is not allowed in organic agriculture. For this reason, great attention has been recently focused on identifying Biological Control Agents (BCA) to implement biological approaches devoid of chemicals. In this direction, we carried out our study in isolating five different non-Saccharomyces yeast strains from local vineyards in the South of Italy as possible BCA. We performed both in vitro and in vivo assays in semi-commercial conditions on detached grape berries stored at 0 °C, simulating the temperature normally used during cold storage, and obtained relevant results. We isolated three M. pulcherrima strains and one L. thermotolerans strain able to largely antagonize the development of the B. cinerea, at both in vitro and in vivo conditions. In particular, we detected the ability of the three isolates of M. pulcherrima strains Ale4, N20/006, and Pr7 and the L. thermotolerans strain N10 to completely inhibit (100% in reduction) the mycelial growth of B. cinerea by producing fungistatic compounds. We found, using an extracellular lytic enzymes activity assay, that such activity could be related to lipid hydrolyzation, β-1,3-glucanase and pectinase activity, and pectinase and protease activity, depending on the yeasts used. Results from our in vitro assays allowed us to hypothesize for M. pulcherrima strains Ale4 and N20/006 a possible combination of both the production of soluble metabolites and volatile organic compounds to antagonize against B. cinerea growth. Moreover, in semi-commercial conditions, the M. pulcherrima strain N20/006 and L. thermotolerans strain N10 showed relevant antagonistic effect also at low concentrations (with a significantly reduction of ‘slip skin’ incidence of 86.4% and 72.7%, respectively), thus highlighting a peculiar property to use in commercial development for organic agriculture and the handling process.
19
Fontana, Daniele Cristina, Samuel de Paula, Abel Galon Torres, Victor Hugo Moura de Souza, Sérgio Florentino Pascholati, Denise Schmidt, and Durval Dourado Neto. "Endophytic Fungi: Biological Control and Induced Resistance to Phytopathogens and Abiotic Stresses." Pathogens 10, no. 5 (May 8, 2021): 570. http://dx.doi.org/10.3390/pathogens10050570.
Full textAbstract:
Plant diseases cause losses of approximately 16% globally. Thus, management measures must be implemented to mitigate losses and guarantee food production. In addition to traditional management measures, induced resistance and biological control have gained ground in agriculture due to their enormous potential. Endophytic fungi internally colonize plant tissues and have the potential to act as control agents, such as biological agents or elicitors in the process of induced resistance and in attenuating abiotic stresses. In this review, we list the mode of action of this group of microorganisms which can act in controlling plant diseases and describe several examples in which endophytes were able to reduce the damage caused by pathogens and adverse conditions. This is due to their arsenal of molecules generated during the interaction by which they form a kind of biological shield in the plant. Furthermore, considering that endophytic fungi can be an important tool in managing for biotic and abiotic stresses due to the large amount of biologically active substances produced, bioprospecting this class of microorganisms is tending to increase and generate valuable products for agriculture.
20
Brescia, Francesca, Anthi Vlassi, Ana Bejarano, Bernard Seidl, Martina Marchetti-Deschmann, Rainer Schuhmacher, and Gerardo Puopolo. "Characterisation of the Antibiotic Profile of Lysobacter capsici AZ78, an Effective Biological Control Agent of Plant Pathogenic Microorganisms." Microorganisms 9, no. 6 (June 17, 2021): 1320. http://dx.doi.org/10.3390/microorganisms9061320.
Full textAbstract:
Determining the mode of action of microbial biocontrol agents plays a key role in their development and registration as commercial biopesticides. The biocontrol rhizobacterium Lysobacter capsici AZ78 (AZ78) is able to inhibit a vast array of plant pathogenic oomycetes and Gram-positive bacteria due to the release of antimicrobial secondary metabolites. A combination of MALDI-qTOF-MSI and UHPLC-HRMS/M was applied to finely dissect the AZ78 metabolome and identify the main secondary metabolites involved in the inhibition of plant pathogenic microorganisms. Under nutritionally limited conditions, MALDI-qTOF-MSI revealed that AZ78 is able to release a relevant number of antimicrobial secondary metabolites belonging to the families of 2,5-diketopiperazines, cyclic lipodepsipeptides, macrolactones and macrolides. In vitro tests confirmed the presence of secondary metabolites toxic against Pythium ultimum and Rhodococcus fascians in AZ78 cell-free extracts. Subsequently, UHPLC-HRMS/MS was used to confirm the results achieved with MALDI-qTOF-MSI and investigate for further putative antimicrobial secondary metabolites known to be produced by Lysobacter spp. This technique confirmed the presence of several 2,5-diketopiperazines in AZ78 cell-free extracts and provided the first evidence of the production of the cyclic depsipeptide WAP-8294A2 in a member of L. capsici species. Moreover, UHPLC-HRMS/MS confirmed the presence of dihydromaltophilin/Heat Stable Antifungal Factor (HSAF) in AZ78 cell-free extracts. Due to the production of HSAF by AZ78, cell-free supernatants were effective in controlling Plasmopara viticola on grapevine leaf disks after exposure to high temperatures. Overall, our work determined the main secondary metabolites involved in the biocontrol activity of AZ78 against plant pathogenic oomycetes and Gram-positive bacteria. These results might be useful for the future development of this bacterial strain as the active ingredient of a microbial biopesticide that might contribute to a reduction in the chemical input in agriculture.
21
Goeden, R. D., and L. T. Kok. "COMMENTS ON A PROPOSED “NEW” APPROACH FOR SELECTING AGENTS FOR THE BIOLOGICAL CONTROL OF WEEDS." Canadian Entomologist 118, no. 1 (January 1986): 51–58. http://dx.doi.org/10.4039/ent11851-1.
Full textAbstract:
AbstractThe “new approach” to selecting biological control agents, as proposed by Hokkanen and Pimentel in 1984, through the use of new exploiter–victim associations is inappropriate for the biological control of weeds because of certain misconceptions in their method. Examples of biological control of weeds cited in their analysis were biased towards cactaceous insects, and cacti are not representative of target weeds. Several of their “new” associations were inaccurate. These inaccuracies are discussed and additional examples are provided to refute the proposed method. Contrary to the recommendation of Hokkanen and Pimentel, new exploiter-victim associations offer limited opportunities for biological control of non-cactaceous weeds with insects, and should not be used as the preferred method in selecting biotic agents for the biological control of weeds.
22
Lemire, Sebastien, Kevin M. Yehl, and Timothy K. Lu. "Phage-Based Applications in Synthetic Biology." Annual Review of Virology 5, no. 1 (September 29, 2018): 453–76. http://dx.doi.org/10.1146/annurev-virology-092917-043544.
Full textAbstract:
Bacteriophage research has been instrumental to advancing many fields of biology, such as genetics, molecular biology, and synthetic biology. Many phage-derived technologies have been adapted for building gene circuits to program biological systems. Phages also exhibit significant medical potential as antibacterial agents and bacterial diagnostics due to their extreme specificity for their host, and our growing ability to engineer them further enhances this potential. Phages have also been used as scaffolds for genetically programmable biomaterials that have highly tunable properties. Furthermore, phages are central to powerful directed evolution platforms, which are being leveraged to enhance existing biological functions and even produce new ones. In this review, we discuss recent examples of how phage research is influencing these next-generation biotechnologies.
23
D. Migunova, Varvara, Natalia S. Tomashevich, Alena N. Konrat, Svetlana V. Lychagina, Valentina M. Dubyaga, Trifone D’Addabbo, Nicola Sasanelli, and Anzhela M. Asaturova. "Selection of Bacterial Strains for Control of Root-Knot Disease Caused by Meloidogyne incognita." Microorganisms 9, no. 8 (August 10, 2021): 1698. http://dx.doi.org/10.3390/microorganisms9081698.
Full textAbstract:
Root-knot disease caused by Meloidogyne incognita leads to significant crop yield losses that may be aggravated by the association with pathogenic fungi and bacteria. Biological agents can be effectively used against the complex disease of root-knot nematode and pathogenic fungi. In this study, 35 bacterial strains were analyzed for their in vitro nematicidal, antagonistic and growth stimulation activities. Based on results from the in vitro assays, grow-box experiments on tomato and cucumber were carried out with the strain BZR 86 of Bacillus velezensis applied at different concentrations. Effects of B. velezensis BZR 86 on the development of root-knot disease were evaluated by recording root gall index, number of galls and number of eggs in egg masses. Application of B. velezensis BZR 86 noticeably decreased the development of root-knot disease on tomato and cucumber plants, as well as significantly increased growth and biomass of cucumber plants in accordance with bacterial concentration. This study seems to demonstrate that strain B. velezensis BZR 86 could be an additional tool for an environmentally safe control of root-knot disease on horticultural crops.
24
Faltin, Franziska, Jana Lottmann, Rita Grosch, and Gabriele Berg. "Strategy to select and assess antagonistic bacteria for biological control ofRhizoctonia solaniKühn." Canadian Journal of Microbiology 50, no. 10 (October 1, 2004): 811–20. http://dx.doi.org/10.1139/w04-063.
Full textAbstract:
A screening strategy was developed to assess the potential of plant-associated bacteria to control diseases caused by Rhizoctonia solani Kühn. About 434 already characterized antagonistic bacterial strains isolated from diverse plant species and microenvironments were evaluated for biocontrol and plant growth promotion by a hierarchical combination of assays. Analyzing in vitro antagonism towards different Rhizoctonia isolates resulted in a selection of 20 potential biocontrol agents. The strains were characterized by their antagonistic mechanisms in vitro as well as their production of the plant growth hormone indole-3-acetic acid. The plant growth promoting effect by antagonistic bacteria was determined using a microtiter plate assay on the basis of lettuce seedlings. Lettuce and sugar beet as host plant were included in the biocontrol experiments in which the antagonistic effect of 17 bacterial isolates could be confirmed in vivo. Sequencing of the 16S rDNA gene and (or) fatty acid methyl ester gas chromatography was used to identify the antagonistic isolates. Molecular fingerprints of isolates obtained by BOX – polymerase chain reaction were compared to avoid further investigation with genetically very similar strains and to obtain unique molecular fingerprints for quality control and patent licensing. According to our strategy, an assessment scheme was developed and four interesting biological control agents, Pseudomonas reactans B3, Pseudomonas fluorescens B1, Serratia plymuthica B4, and Serratia odorifera B6, were found. While S. plymuthica B4 was the best candidate to biologically control Rhizoctonia in lettuce, P. reactans B3 was the best candidate to suppress the pathogen in sugar beet.Key words: biocontrol, Rhizoctonia solani, lettuce, sugar beet, antagonistic bacteria.
25
Moore, Patrick S., and Yuan Chang. "Molecular virology of Kaposi's sarcoma–associated herpesvirus." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 356, no. 1408 (April 29, 2001): 499–516. http://dx.doi.org/10.1098/rstb.2000.0777.
Full textAbstract:
Kaposi's sarcoma–associated herpesvirus (KSHV), the most recently discovered human tumour virus, is the causative agent of Kaposi's sarcoma, primary effusion lymphoma and some forms of Castleman's disease. KSHV is a rhadinovirus, and like other rhadinoviruses, it has an extensive array of regulatory genes obtained from the host cell genome. These pirated KSHV proteins include homologues to cellular CD21, three different β–chemokines, IL–6, BCL–2, several different interferon regulatory factor homologues, Fas–ligand ICE inhibitory protein (FLIP), cyclin D and a G–protein–coupled receptor, as well as DNA synthetic enzymes including thymidylate synthase, dihydrofolate reductase, DNA polymerase, thymidine kinase and ribonucleotide reductases. Despite marked differences between KSHV and Epstein–Barr virus, both viruses target many of the same cellular pathways, but use different strategies to achieve the same effects. KSHV proteins have been identified which inhibit cell–cycle regulation checkpoints, apoptosis control mechanisms and the immune response regulatory machinery. Inhibition of these cellular regulatory networks appears to be a defensive means of allowing the virus to escape from innate antiviral immune responses. However, due to the overlapping nature of innate immune and tumour–suppressor pathways, inhibition of these regulatory networks can lead to unregulated cell proliferation and may contribute to virus–induced tumorigenesis.
26
Shahid, Ali, Qayyum Rao, Allah Bakhsh, and Tayyab Husnain. "Entomopathogenic fungi as biological controllers: New insights into their virulence and pathogenicity." Archives of Biological Sciences 64, no. 1 (2012): 21–42. http://dx.doi.org/10.2298/abs1201021s.
Full textAbstract:
Entomopathogenic fungi vary considerably in their mode of action and virulence. Successful infection depends primarily on the adherence and penetration ability of a fungus to the host integuments. A variety of extracellular enzymes is produced during the degradation of insect integument. The attempts to control insects have changed over time from chemicals to natural control methods. This is why the development of natural methods of insect control or biopesticides, is preferred. By the use of fungal entomopathogens, insect pests can be controlled. There is no doubt that insects have been used for many years, but their effective use in the field remains elusive. However, their additional role in nature has also been discovered. Comparison of entomopathogens with conventional chemical pesticides depends on their efficiency and cost. In addition to efficiency, there are advantages in using microbial control agents, such as human safety and other non-target organisms; pesticide residues are minimized in food and biodiversity increased in managed ecosystems. In the present review the pathogenicity and virulence of entomopathogenic fungi and their role as biological control agents using biotechnology will be discussed.
27
Malausa, Thibaut, Mathilde Delaunay, Alexandre Fleisch, Géraldine Groussier-Bout, Sylvie Warot, Didier Crochard, Emilio Guerrieri, et al. "Investigating Biological Control Agents for Controlling Invasive Populations of the Mealybug Pseudococcus comstocki in France." PLOS ONE 11, no. 6 (June 30, 2016): e0157965. http://dx.doi.org/10.1371/journal.pone.0157965.
Full text
28
Hélène, Claude, and Nguyen T. Thuong. "Control of gene expression by oligonucleotides covalently linked to intercalating agents." Genome 31, no. 1 (January 1, 1989): 413–21. http://dx.doi.org/10.1139/g89-062.
Full textAbstract:
Oligodeoxynucleotides covalently linked to intercalating agents selectively recognize the complementary sequence of the oligonucleotide. The intercalating agent provides an additional binding energy which stabilizes the complex. These substances can be used in vitro to block mRNA translation. In cell cultures they are able to inhibit the cytopathic effect of viruses, such as influenza virus and the oncogenic virus SV40. They kill trypanosomes in culture as a result of protein synthesis inhibition. A reactive group can be attached to an oligodeoxynucleotide in order to achieve site-directed modifications of the target sequence. Metal complexes of EDTA, phenanthroline or porphyrins induce cleavage reactions of the phosphodiester backbone in both DNA and RNA. Photoactive groups can be used to modify bases in the complementary sequence. The double helix can be recognized and modified by oligonucleotides that bind to the major groove, forming a local triple helix. These site-directed modifications may inhibit biological processes. The oligonucleotide can be made resistant to nuclease digestion by substituting the synthetic α-anomers of nucleosides to the natural β-nucleosides. These results provide the basis for the design of gene-specific inhibitors that can be used as tools in molecular and cellular biology. They also suggest new approaches for the rational development of selective anti-viral, anti-parasitic, and anti-tumoral agents.Key words: oligonucleotides, intercalating agents, α-nucleosides, DNA cleavage, triple helix, photo cross-linking.
29
Etebarian, Hassan-Reza, Peter L. Sholberg, Kenneth C. Eastwell, and Ronald J. Sayler. "Biological control of apple blue mold withPseudomonas fluorescens." Canadian Journal of Microbiology 51, no. 7 (July 1, 2005): 591–98. http://dx.doi.org/10.1139/w05-039.
Full textAbstract:
Pseudomonas fluorescens isolate 1100-6 was evaluated as a potential biological control agent for apple blue mold caused by Penicillium expansum or Penicillium solitum. Both the wild-type isolate 1100-6 and a genetically modified derivative labeled with the gene encoding the green fluorescent protein (GFP) were compared. The P. fluorescens isolates with or without GFP equally reduced the growth of Penicillium spp. and produced large zones of inhibition in dual culture plate assays. Cell-free metabolites produced by the bacterial antagonists reduced the colony area of Penicillium isolates by 17.3% to 78.5%. The effect of iron chelate on the antagonistic potential of P. fluorescens was also studied. The use of iron chelate did not have a major effect on the antagonistic activity of P. fluorescens. With or without GFP, P. fluorescens significantly reduced the severity and incidence of apple decay by 2 P. expansum isolates after 11 d at 20 °C and by P. expansum and P. solitum after 25 d at 5 °C when the biocontrol agents were applied in wounds 24 or 48 h before challenging with Penicillium spp. Populations of P. fluorescens labeled with the GFP were determined 1, 9, 14, and 20 d after inoculation at 5 °C. The log CFU/mL per wound increased from 6.95 at the time of inoculation to 9.12 CFU/mL (P < 0.05) 25 d after inoculation at 5 °C. The GFP strain did not appear to penetrate deeply into wounds based on digital photographs taken with an inverted fluorescence microscope. These results indicate that P. fluorescens isolate 1100-6 could be an important new biological control for apple blue mold.Key words: Penicillium expansum, P. solitum, postharvest disease, Malus, GFP.
30
Verschure, Paul F. M. J. "Synthetic consciousness: the distributed adaptive control perspective." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1701 (August 19, 2016): 20150448. http://dx.doi.org/10.1098/rstb.2015.0448.
Full textAbstract:
Understanding the nature of consciousness is one of the grand outstanding scientific challenges. The fundamental methodological problem is how phenomenal first person experience can be accounted for in a third person verifiable form, while the conceptual challenge is to both define its function and physical realization. The distributed adaptive control theory of consciousness (DACtoc) proposes answers to these three challenges. The methodological challenge is answered relative to the hard problem and DACtoc proposes that it can be addressed using a convergent synthetic methodology using the analysis of synthetic biologically grounded agents, or quale parsing. DACtoc hypothesizes that consciousness in both its primary and secondary forms serves the ability to deal with the hidden states of the world and emerged during the Cambrian period, affording stable multi-agent environments to emerge. The process of consciousness is an autonomous virtualization memory, which serializes and unifies the parallel and subconscious simulations of the hidden states of the world that are largely due to other agents and the self with the objective to extract norms. These norms are in turn projected as value onto the parallel simulation and control systems that are driving action. This functional hypothesis is mapped onto the brainstem, midbrain and the thalamo-cortical and cortico-cortical systems and analysed with respect to our understanding of deficits of consciousness. Subsequently, some of the implications and predictions of DACtoc are outlined, in particular, the prediction that normative bootstrapping of conscious agents is predicated on an intentionality prior. In the view advanced here, human consciousness constitutes the ultimate evolutionary transition by allowing agents to become autonomous with respect to their evolutionary priors leading to a post-biological Anthropocene. This article is part of the themed issue ‘The major synthetic evolutionary transitions’.
31
Read, Andrew F., Andrea L. Graham, and Lars Råberg. "Animal Defenses against Infectious Agents: Is Damage Control More Important Than Pathogen Control." PLoS Biology 6, no. 12 (December 23, 2008): e1000004. http://dx.doi.org/10.1371/journal.pbio.1000004.
Full text
32
Wilson, Rona, Patricia Hart, Pedro Piccardo, Nora Hunter, Cristina Casalone, Thierry Baron, and Rona M. Barron. "Bovine PrP expression levels in transgenic mice influence transmission characteristics of atypical bovine spongiform encephalopathy." Journal of General Virology 93, no. 5 (May 1, 2012): 1132–40. http://dx.doi.org/10.1099/vir.0.040030-0.
Full textAbstract:
Until recently, transmissible spongiform encephalopathy (TSE) disease in cattle was thought to be caused by a single agent strain, bovine spongiform encephalopathy (BSE) (classical BSE or BSE-C). However, due to the initiation of a large-scale surveillance programme throughout Europe, two atypical BSE strains, bovine amyloidotic spongiform encephalopathy (BASE, also named BSE-L) and BSE-H have since been discovered. These atypical BSE isolates have been previously transmitted to a range of transgenic mouse models overexpressing PrP from different species at different levels, on a variety of genetic backgrounds. To control for genetic background and expression level in the analysis of these isolates, we performed here a comprehensive comparison of the neuropathological and molecular properties of all three BSE agents (BASE, BSE-C and BSE-H) upon transmission into the same gene-targeted transgenic mouse line expressing the bovine prion protein (Bov6) and a wild-type control of the same genetic background. Significantly, upon challenge with these BSE agents, we found that BASE did not produce shorter survival times in these mice compared with BSE-C, contrary to previous studies using overexpressing bovine transgenic mice. Amyloid plaques were only present in mice challenged with atypical BSE and neuropathological features, including intensity of PrP deposition in the brain and severity of vacuolar degeneration were less pronounced in BASE compared with BSE-C-challenged mice.
33
Inoue, Jun, Kosuke Sato, Masashi Ninomiya, and Atsushi Masamune. "Envelope Proteins of Hepatitis B Virus: Molecular Biology and Involvement in Carcinogenesis." Viruses 13, no. 6 (June 11, 2021): 1124. http://dx.doi.org/10.3390/v13061124.
Full textAbstract:
The envelope of hepatitis B virus (HBV), which is required for the entry to hepatocytes, consists of a lipid bilayer derived from hepatocyte and HBV envelope proteins, large/middle/small hepatitis B surface antigen (L/M/SHBs). The mechanisms and host factors for the envelope formation in the hepatocytes are being revealed. HBV-infected hepatocytes release a large amount of subviral particles (SVPs) containing L/M/SHBs that facilitate escape from the immune system. Recently, novel drugs inhibiting the functions of the viral envelope and those inhibiting the release of SVPs have been reported. LHBs that accumulate in ER is considered to promote carcinogenesis and, especially, deletion mutants in the preS1/S2 domain have been reported to be associated with the development of hepatocellular carcinoma (HCC). In this review, we summarize recent reports on the findings regarding the biological characteristics of HBV envelope proteins, their involvement in HCC development and new agents targeting the envelope.
34
Farooq, Saleem, Aashiq Hussain, Mushtaq A. Qurishi, Abid Hamid, and S. Koul. "Synthesis and Biological Evaluation of Novel Triazoles Linked 7-hydroxycoumarin as Potent Cytotoxic Agents." Anti-Cancer Agents in Medicinal Chemistry 18, no. 11 (January 28, 2019): 1531–39. http://dx.doi.org/10.2174/1871520618666171229222956.
Full textAbstract:
Background: BacCancer is regarded as second leading cause of death worldwide. Therefore, there is a high demand for the discovery, development and improvement of novel anti-cancer agents which could efficiently prevent proliferative pathways and clonal expansion of cells. Objective: In view of this, a new series of bioactive scaffolds viz triazoles linked 7-hydroxycoumarin (1) were synthesized using click chemistry approach. Method: All the synthesized compounds were screened for cytotoxicity against a panel of seven different human cancer cell lines viz. Colon (Colo-205 and HCT-116), breast (MCF-7), lung (NCI-H322 and A549), prostate (PC-3) and skin (A-431) using 3-(4,5-Dimethylthiazol-yl)-diphenyl tetrazoliumbromide (MTT) assay. Results: Among all tested analogs, compound 5, displayed better cytotoxic activity as compared to the parent 7- hydroxycoumarin (1) with IC50 of 5.1, 22.7, 14.3 and 10.2 µM against breast (MCF-7), lung (NCI- H322), prostate (PC-3) and skin (A-431) cancer cell lines, respectively; the compound 5 was 8-fold more sensitive against MCF-7 than the parent 7-hydroxycoumarin. Moreover, Compound 5 induced both cytotoxic as well as cytostatic effects via induction of apoptosis and G1 phase arrest, respectively in breast cancer cells (MCF-7). The apoptotic cell population enhanced to 18.8% at 8 µM of 5 from 9.8% in case of negative control, while G1 phase arrest increased to 54.4% at 8 µM compared to negative control of 48.1%. Moreover, Compound 5 also exhibited a remarkable decrease in mitochondrial membrane potential (ΛΨm) leading to apoptosis of cancer cells used. Conclusion: The structure-activity relationship study revealed that the derivatives bearing electron-withdrawing substituents were more effective. The present study resulted in identification of the compounds demonstrating broad spectrum cytotoxic activity.
35
Aiello, Dalia, Alessandro Vitale, Giancarlo Perrone, Matilde Tessitori, and Giancarlo Polizzi. "Can Biological Control Agents Reduce Multiple Fungal Infections Causing Decline of Milkwort in Ornamental Nursery?" Plants 9, no. 12 (December 1, 2020): 1682. http://dx.doi.org/10.3390/plants9121682.
Full textAbstract:
This research evaluates biological control agents (BCAs) and fungicide alone and in combination for the management of decline caused by multiple fungi on milkwort (Polygala myrtifolia). Four experiments were performed in a greenhouse within a nursery located in Catania province (southern Italy). The activity of fungicides and biological control agents was evaluated by calculating the plant mortality (%) and recovery frequency (%) of different fungi associated with symptomatic tissue. Comprehensively, boscalid + pyraclostrobin and fosetyl-Al showed the best results in managing disease complex on milkwort. Biological control agents provided, on average, the lowest performances; nevertheless, in most cases, they were able to significantly reduce multiple infections and sometimes when combined with fungicide enhanced the effectiveness. The molecular analysis of 86 isolates obtained from symptomatic tissue allowed to identify the fungi involved in the disease as Calonectriapauciramosa, C. pseudomexicana, Fusariumoxysporum, Neocosmospora solani (syn. F. solani) and binucleate Rhizoctonia AG-R. Calonectriapseudomexicana never reported on milkwort and in Europe was inoculated on P. myrtifolia potted healthy cuttings and produced crown and root rot after 40 days. Our findings represent the first worldwide report about disease complex of milkwort caused by several fungi (Calonectria spp., Fusarium spp. and binucleate Rhizoctonia) and on the effects of integrated control strategies to manage this disease in the nursery.
36
Asaturova, Anzhela, Margarita Shternshis, Vera Tsvetkova, Tatyana Shpatova, Vladislava Maslennikova, Natalya Zhevnova, and Anna Homyak. "Biological control of important fungal diseases of potato and raspberry by two Bacillus velezensis strains." PeerJ 9 (June 14, 2021): e11578. http://dx.doi.org/10.7717/peerj.11578.
Full textAbstract:
Stem canker and black scurf caused by Rhizoctonia solani are the important diseases in potato, while spur blight caused by Didymella applanata is a major disease in red raspberry. In Western Siberia, both crops are grown predominantly in small-scale farming that requires maximal usage of biological products for plant protection instead of chemicals. We evaluated two promising Bacillus velezensis strains BZR 336 g and BZR 517 isolated in the south of Russia (45°1′N, 38°59′E) for their biological control potentials against the potato and red raspberry diseases under the more severe weather conditions of Western Siberia (55°1′N, 82°55′ E). We tested two techniques to apply biocontrol agents: (1) coating the seeds (potato tubers) and (2) spraying over the plants (raspberry canes). In each case, we estimated B. velezensis strains on two plant cultivars differed by the disease resistance. The degree of B. velezensis influence on disease incidence and severity depended on the bacterial strain, the protected plant, and its cultivar. We also demonstrated that two B. velezensis strains significantly stimulated plant growth of potato, which contributed to the plant productivity on both cultivars. The BZR 336 g strain affected the potato productivity more than the BZR 517 strain. Under the influence of both bacterial strains, raspberry yield was significantly higher compared to the control on the susceptible cultivar. These findings indicated that two southern B. velezensis strains had proved their efficacy as biological control agents in the control of the serious fungal infection of potato and raspberry plants under the more severe ecological conditions of Western Siberia. For the first time, we demonstrated B. velezensis strains potential for use as biological control agents against R. solani on potato, and against D. applanata on red raspberry.
37
Zhou, Duanyong, Jianping Xu, Jianyong Dong, Haixia Li, Da Wang, Juan Gu, Ke-Qin Zhang, and Ying Zhang. "Historical Differentiation and Recent Hybridization in Natural Populations of the Nematode-Trapping Fungus Arthrobotrys oligospora in China." Microorganisms 9, no. 9 (September 9, 2021): 1919. http://dx.doi.org/10.3390/microorganisms9091919.
Full textAbstract:
Maintaining the effects of nematode-trapping fungi (NTF) agents in order to control plant-parasitic nematodes (PPNs) in different ecological environments has been a major challenge in biological control applications. To achieve such an objective, it is important to understand how populations of the biocontrol agent NTF are geographically and ecologically structured. A previous study reported evidence for ecological adaptation in the model NTF species Arthrobotrys oligospora. However, their large-scale geographic structure, patterns of gene flow, their potential phenotypic diversification, and host specialization remain largely unknown. In this study, we developed a new panel of 20 polymorphic short tandem repeat (STR) markers and analyzed 239 isolates of A. oligospora from 19 geographic populations in China. In addition, DNA sequences at six nuclear gene loci and strain mating types (MAT) were obtained for these strains. Our analyses suggest historical divergence within the A. oligospora population in China. The genetically differentiated populations also showed phenotypic differences that may be related to their ecological adaptations. Interestingly, our analyses identified evidence for recent dispersion and hybridization among the historically subdivided geographic populations in nature. Together, our results indicate a changing population structure of A. oligospora in China and that care must be taken in selecting the appropriate strains as biocontrol agents that can effectively reproduce in agriculture soil while maintaining their nematode-trapping ability.
38
MacQuarrie, Chris J. K., D. B. Lyons, M. Lukas Seehausen, and Sandy M. Smith. "A history of biological control in Canadian forests, 1882–2014." Canadian Entomologist 148, S1 (January 14, 2016): S239—S269. http://dx.doi.org/10.4039/tce.2015.66.
Full textAbstract:
AbstractBiological control has been an important tactic in the management of Canadian forests for over a century, but one that has had varied success. Here, we review the history of biological control programmes using vertebrate and invertebrate parasitoids and predators against insects in Canadian forests. Since roughly 1882, 41 insect species have been the target of biological control, with approximately equal numbers of both native and non-native species targeted. A total of 161 species of biological control agents have been released in Canadian forests, spanning most major orders of insects, as well as mites and mammals. Biological control has resulted in the successful suppression of nine pest species, and aided in the control of an additional six species. In this review, we outline the chronological history of major projects across Canadian forests, focussing on those that have had significant influence for the development of biological control. The historical data clearly illustrate a rise and fall in the use of biological control as a tactic for managing forest pests, from its dominance in the 1940s and 1950s to its current low level. The strategic implementation of these biological control programmes, their degree of success, and the challenges faced are discussed, along with the discipline’s shifting relationship to basic science and the environmental viewpoints surrounding its use.
39
Duran-Vila, Núria. "Viroids as Companions of a Professional Career." Viruses 11, no. 3 (March 12, 2019): 245. http://dx.doi.org/10.3390/v11030245.
Full textAbstract:
Since the early 1970s when “virus-like” agents were considered as the cause of two diseases (potato spindle tuber and citrus exocortis), their study and further characterization have been linked to the development and use of molecular biology tools. Sucrose density gradient centrifugation and polyacrylamide gel electrophoresis (PAGE) played a critical role in the pioneering studies of PSTVd and citrus exocortis viroid (CEVd). This was later modified by using other PAGEs (sequential PAGE, return PAGE, two-dimensional PAGE), and/or different staining methods (ethidium bromide, silver nitrate, etc.). Since then, disease-causing agents suspected to be viroids were usually subjected to a number of tests to define their: (i) Molecular nature (RNA or DNA; single stranded or double stranded; circular or linear RNA); (ii) molecular weight; (iii) secondary and tertiary structure. Further biological assays are also essential to establish the relationship of a viroid with plant disease and to fulfill Koch’s postulates.
40
Chen, Minjie, Shuiyun Lan, Rong Ou, Graeme E. Price, Hong Jiang, Juan Carlos de la Torre, and Demetrius Moskophidis. "Genomic and biological characterization of aggressive and docile strains of lymphocytic choriomeningitis virus rescued from a plasmid-based reverse-genetics system." Journal of General Virology 89, no. 6 (June 1, 2008): 1421–33. http://dx.doi.org/10.1099/vir.0.83464-0.
Full textAbstract:
Arenaviruses include several causative agents of haemorrhagic fever disease in humans. In addition, the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) is a superb model for the study of virus–host interactions, including the basis of viral persistence and associated diseases. There is little understanding about the molecular mechanisms concerning the regulation and specific role of viral proteins in modulating arenavirus–host cell interactions either associated with an acute or persistent infection, and associated disease. Here, we report the genomic and biological characterization of LCMV strains ‘Docile’ (persistent) and ‘Aggressive’ (not persistent) recovered from cloned cDNA via reverse genetics. Our results confirmed that the cloned viruses accurately recreated the in vivo phenotypes associated with the corresponding natural Docile and Aggressive viral isolates. In addition, we provide evidence that the ability of the Docile strain to persist is determined by the nature of both S and L RNA segments. Thus, our findings provide the foundation for studies aimed at gaining a detailed understanding of viral determinants of LCMV persistence in its natural host, which may aid in the development of vaccines to prevent or treat the diseases caused by arenaviruses in humans.
41
Amer, G. A., and R. S. Utkhede. "Development of formulations of biological agents for management of root rot of lettuce and cucumber." Canadian Journal of Microbiology 46, no. 9 (September 1, 2000): 809–16. http://dx.doi.org/10.1139/w00-063.
Full textAbstract:
The effect of various carrier formulations of Bacillus subtilis and Pseudomonas putida were tested on germination, growth, and yield of lettuce and cucumber crops in the presence of Pythium aphanidermatum and Fusarium oxysporum f.sp. cucurbitacearum, respectively. Survival of B. subtilis and P. putida in various carriers under refrigeration (about 0°C) and at room temperature (about 22°C) was also studied. In all carrier formulations, B. subtilis strain BACT-0 survived up to 45 days. After 45 days of storage at room temperature (about 22°C), populations B. subtilis strain BACT-0 were significantly higher in vermiculite, kaolin, and bacterial broth carriers compared with other carriers. Populations of P. putida were significantly higher in vermiculite, peat moss, wheat bran, and bacterial broth than in other carriers when stored either under refrigeration (about 0°C) or at room temperature (about 22°C) for 15 or 45 days. Germination of lettuce seed was not affected in vermiculite, talc, kaolin, and peat moss carriers, but germination was significantly reduced in alginate and bacterial broth carriers of B. subtilis compared to the non-treated control. Germination of cucumber seed was not affected by any of the carriers. Significantly higher fresh lettuce and root weights were observed in vermiculite and kaolin carriers of B. subtilis compared with P. aphanidermatum-inoculated control plants. Lettuce treated with vermiculite, and kaolin carriers of B. subtilis, or non-inoculated control lettuce plants had significantly lower root rot ratings than talc, peat moss, bacterial broth, and P. aphanidermatum-inoculated control plants. Growth and yield of cucumber plants were significantly higher in vermiculite-based carrier of P. putida than the other carriers and Fusarium oxysporum f.sp. cucurbitacearum-inoculated plants.Key words: Bacillus subtilis, Pseudomonas putida, Fusarium oxysporum f.sp. cucurbitacearum, Pythium aphanidermatum, talc, vermiculite, alginate, kaolin, peat moss, wheat bran, oat bran.
42
Utkhede, R. S., and S. Mathur. "Biological control of stem canker of greenhouse tomatoes caused by Botrytis cinerea." Canadian Journal of Microbiology 48, no. 6 (June 1, 2002): 550–54. http://dx.doi.org/10.1139/w02-043.
Full textAbstract:
Experiments were conducted to study the effect of various chemical and biological agents on stem canker caused by Botrytis cinerea Pers.: Fr. on tomato plants grown in sawdust under near-commercial greenhouse conditions. Lesion lengths following treatment with RootShield® and strain S33 of Rhodosporidium diobovatum Newell & Hunter, applied as post-inoculation sprays, were significantly smaller than those in inoculated controls. These treatments also increased fruit yield and decreased the number of dead plants compared with inoculated controls. Decree®, Prestop®, and R. diobovatum S33, applied as sprays, prevented the occurrence of stem canker and increased fruit yield in tomato. The number of dead plants was also smaller with these treatments than with the other treatments and in inoculated controls. These results suggest that, in tomato, post-inoculation sprays of RootShield® and R. diobovatum S33 can reduce lesion lengths, and that a preventive spray of Decree®, Prestop®, and R. diobovatum S33 might prevent stem canker, under near-commercial greenhouse conditions.Key words: biological control, Botrytis cinerea, Bacillus subtilis, Rhodosporidium diobovatum, grey mold.
43
Fernández-Bravo, María, Florian Gschwend, Johanna Mayerhofer, Anna Hug, Franco Widmer, and Jürg Enkerli. "Land-Use Type Drives Soil Population Structures of the Entomopathogenic Fungal Genus Metarhizium." Microorganisms 9, no. 7 (June 25, 2021): 1380. http://dx.doi.org/10.3390/microorganisms9071380.
Full textAbstract:
Species of the fungal genus Metarhizium are globally distributed pathogens of arthropods, and a number of biological control products based on these fungi have been commercialized to control a variety of pest arthropods. In this study, we investigate the abundance and population structure of Metarhizium spp. in three land-use types—arable land, grassland, and forest—to provide detailed information on habitat selection and the factors that drive the occurrence and abundance of Metarhizium spp. in soil. At 10 sites of each land-use type, which are all part of the Swiss national soil-monitoring network (NABO), Metarhizium spp. were present at 8, 10, and 4 sites, respectively. On average, Metarhizium spp. were most abundant in grassland, followed by forest and then arable land; 349 Metarhizium isolates were collected from the 30 sites, and sequence analyses of the nuclear translation elongation factor 1α gene, as well as microsatellite-based genotyping, revealed the presence of 13 Metarhizium brunneum, 6 Metarhizium robertsii, and 3 Metarhizium guizhouense multilocus genotypes (MLGs). With 259 isolates, M. brunneum was the most abundant species, and significant differences were detected in population structures between forested and unforested sites. Among 15 environmental factors assessed, C:N ratio, basal respiration, total carbon, organic carbon, and bulk density significantly explained the variation among the M. brunneum populations. The information gained in this study will support the selection of best-adapted isolates as biological control agents and will provide additional criteria for the adaptation or development of new pest control strategies.
44
Chiba, Sotaro, Lakha Salaipeth, Yu-Hsin Lin, Atsuko Sasaki, Satoko Kanematsu, and Nobuhiro Suzuki. "A Novel Bipartite Double-Stranded RNA Mycovirus from the White Root Rot Fungus Rosellinia necatrix: Molecular and Biological Characterization, Taxonomic Considerations, and Potential for Biological Control." Journal of Virology 83, no. 24 (October 14, 2009): 12801–12. http://dx.doi.org/10.1128/jvi.01830-09.
Full textAbstract:
ABSTRACT White root rot, caused by the ascomycete Rosellinia necatrix, is a devastating disease worldwide, particularly in fruit trees in Japan. Here we report on the biological and molecular properties of a novel bipartite double-stranded RNA (dsRNA) virus encompassing dsRNA-1 (8,931 bp) and dsRNA-2 (7,180 bp), which was isolated from a field strain of R. necatrix, W779. Besides the strictly conserved 5′ (24 nt) and 3′ (8 nt) terminal sequences, both segments show high levels of sequence similarity in the long 5′ untranslated region of approximately 1.6 kbp. dsRNA-1 and -2 each possess two open reading frames (ORFs) named ORF1 to -4. Although the protein encoded by 3′-proximal ORF2 on dsRNA-1 shows sequence identities of 22 to 32% with RNA-dependent RNA polymerases from members of the families Totiviridae and Chrysoviridae, the remaining three virus-encoded proteins lack sequence similarities with any reported mycovirus proteins. Phylogenetic analysis showed that the W779 virus belongs to a separate clade distinct from those of other known mycoviruses. Purified virions ∼50 nm in diameter consisted of dsRNA-1 and -2 and a single major capsid protein of 135 kDa, which was shown by peptide mass fingerprinting to be encoded by dsRNA-1 ORF1. We developed a transfection protocol using purified virions to show that the virus was responsible for reduction of virulence and mycelial growth in several host strains. These combined results indicate that the W779 virus is a novel bipartite dsRNA virus with potential for biological control (virocontrol), named Rosellinia necatrix megabirnavirus 1 (RnMBV1), that possibly belongs to a new virus family.
45
Mason, Peter G., and Martin A. Erlandson. "INVITATION PAPER (C.P. ALEXANDER FUND): THE POTENTIAL OF BIOLOGICAL CONTROL FOR MANAGEMENT OF GRASSHOPPERS (ORTHOPTERA: ACRIDIDAE) IN CANADA." Canadian Entomologist 126, no. 6 (December 1994): 1459–91. http://dx.doi.org/10.4039/ent1261459-6.
Full textAbstract:
AbstractIn Canada biological control of grasshoppers has been studied since the 1930s. Previous attempts at "classical" introductions have not been successful. Native parasitoids, especially sarcophagid flies, have a significant impact on grasshopper populations during certain times but the required conditions and regulatory potential are not understood. Sarcophagids, especially Kellymyia kellyi (Aldrich), and the mermithid nematodes Agamermis decaudate Cobb, Steiner, and Christie and Mermis subnigricans Cobb have some potential as inundative agents. Invertebrate predators appear to impact on egg and early-instar nymphal grasshoppers, and vertebrates, especially birds, help to regulate later instars and adults. The role of microbial pathogens in the population dynamics of grasshoppers in western Canada has long been recognized, particularly with regard to entomophthoran fungi. The possibility of utilizing the microsporidan Nosema locustae Canning for suppression of grasshopper populations has been postulated since the 1970s and field evaluations of its potential have been conducted in Saskatchewan and Alberta. More recently, considerable work, both basic and applied, has demonstrated the potential of various fungus isolates pathogenic to grasshoppers as both "classical" and inundative control agents. Entomopoxvirus isolates from grasshoppers also show potential as biological control agents of grasshoppers but this potential has yet to be investigated in field situations. It is clear, however, that no single microbial pathogen will be the panacea of grasshopper control. It is suggested that future biological control research focus on acquiring a better understanding of the requirements and quantitative effects of parasitoids and predators on grasshopper populations. Emphasis should also be placed on developing integrated pest management programs that utilize local natural enemies (nematodes and microorganisms) for inundative control during outbreaks.
46
Sobhy, Islam S., Matthias Erb, Yonggen Lou, and Ted C. J. Turlings. "The prospect of applying chemical elicitors and plant strengtheners to enhance the biological control of crop pests." Philosophical Transactions of the Royal Society B: Biological Sciences 369, no. 1639 (April 5, 2014): 20120283. http://dx.doi.org/10.1098/rstb.2012.0283.
Full textAbstract:
An imminent food crisis reinforces the need for novel strategies to increase crop yields worldwide. Effective control of pest insects should be part of such strategies, preferentially with reduced negative impact on the environment and optimal protection and utilization of existing biodiversity. Enhancing the presence and efficacy of native biological control agents could be one such strategy. Plant strengthener is a generic term for several commercially available compounds or mixtures of compounds that can be applied to cultivated plants in order to ‘boost their vigour, resilience and performance’. Studies into the consequences of boosting plant resistance against pests and diseases on plant volatiles have found a surprising and dramatic increase in the plants' attractiveness to parasitic wasps. Here, we summarize the results from these studies and present new results from assays that illustrate the great potential of two commercially available resistance elicitors. We argue that plant strengtheners may currently be the best option to enhance the attractiveness of cultivated plants to biological control agents. Other options, such as the genetic manipulation of the release of specific volatiles may offer future solutions, but in most systems, we still miss fundamental knowledge on which key attractants should be targeted for this approach.
47
Abou-Haidar, André, Patil Tawidian, Hana Sobh, Margaret Skinner, Bruce Parker, and Yusuf Abou-Jawdah. "Efficacy of Phytoseiulus persimilis and Amblyseius swirskii for integrated pest management for greenhouse cucumbers under Mediterranean environmental conditions." Canadian Entomologist 153, no. 5 (May 26, 2021): 598–615. http://dx.doi.org/10.4039/tce.2021.15.
Full textAbstract:
AbstractThe greenhouse cucumber pests, Bemisia tabaci (Hemiptera: Aleyrodidae), Frankliniella occidentalis (Thysanoptera: Thripidae), and Tetranychus urticae (Acari: Tetranychidae), are major threats to the production of greenhouse cucumbers (Cucurbitaceae) in Lebanon. The development of insecticide resistance by these pests has prompted the use of alternative and sustainable pest management strategies. In this study, we used integrated pest management strategies, including the release of the biological control agents, Amblyseius swirskii Athias-Henriot (Mesostigmata: Phytoseiidae) and Phytoseiulus persimilis Athias-Henriot (Mesostigmata: Phytoseiidae), to control whitefly, thrips, and two-spotted spider mite populations on greenhouse cucumber plants in two commercial production sites (sites A and B). We also compared the efficacy of pest population suppression using the integrated pest management strategy with that of chemical pest control. Our results show that biological control effectively maintains the cucumber pest populations below the economic threshold when coupled with additional integrated pest management measures. In addition, we show that biological control agents were equally or more effective in pest population suppression compared to eight and 12 insecticidal and acaricidal sprays performed in the control greenhouses at sites A and B, respectively. Altogether, our results show the efficacy of adopting integrated pest management and biological control for pest population suppression in greenhouse cucumber production under Mediterranean environmental conditions.
48
Eid, Ahmad M., Mohammed Hawash, Johnny Amer, Abdullah Jarrar, Samira Qadri, Iman Alnimer, Aya Sharaf, et al. "Synthesis and Biological Evaluation of Novel Isoxazole-Amide Analogues as Anticancer and Antioxidant Agents." BioMed Research International 2021 (March 9, 2021): 1–9. http://dx.doi.org/10.1155/2021/6633297.
Full textAbstract:
Cancer now is one of the leading causes of mortality in the world. There has been a lot of effort to discover new anticarcinogenic agents that allow treatment with fewer side effects. A series of isoxazole-carboxamide derivatives (2a–2g) were synthesised and evaluated for their cytotoxic activity against breast (MCF-7), cervical (HeLa), and liver (Hep3B) cancer cell lines and their antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The results showed that 2d and 2e were the most active compounds against Hep3B cells, with a half-maximal inhibitory concentration (IC50) of around 23 μg/ml; 2d showed the highest activity against HeLa cells, with an IC50 15.48 μg/ml. However, 2a had the lowest IC50 (39.80 μg/ml) against MCF-7 cells. By contrast, compound 2g was inactive against all cancer cell lines, with IC50 values >400 μg/ml. Both 2d and 2e reduced Hep3B secretion of alpha-fetoprotein (to 1829.33 ± 65.91 ng / ml and 1758.66 ± 54.04 ng / ml , respectively). Furthermore, in cell cycle analysis, 2d and 2e induced a delay in the G2/M phase of 18.07%, which is similar to the doxorubicin positive control. Moreover, 2d and 2e reduced the necrosis rate of Hep3B threefold and instead shifted the cells to apoptosis. Our results indicate that 2d and 2e have potent and promising anticancer activity. However, compound 2a was the most active as antioxidant agent ( I C 50 = 7.8 ± 1.21 μ g / ml ) compared with Trolox as a positive control (IC50 2.75 μg/ml).
49
Zwart, Ali, Strien, Schijlen, Wang, Werf, and Vlak. "Identification of Loci Associated with Enhanced Virulence in Spodoptera litura Nucleopolyhedrovirus Isolates Using Deep Sequencing." Viruses 11, no. 9 (September 17, 2019): 872. http://dx.doi.org/10.3390/v11090872.
Full textAbstract:
Spodoptera litura is an emerging pest insect in cotton and arable crops in Central Asia. To explore the possibility of using baculoviruses as biological control agents instead of chemical pesticides, in a previous study we characterized a number of S. litura nucleopolyhedrovirus (SpltNPV) isolates from Pakistan. We found significant differences in speed of kill, an important property of a biological control agent. Here we set out to understand the genetic basis of these differences in speed of kill, by comparing the genome of the fast-killing SpltNPV-Pak-TAX1 isolate with that of the slow-killing SpltNPV-Pak-BNG isolate. These two isolates and the SpltNPV-G2 reference strain from China were deep sequenced with Illumina. As expected, the two Pakistani isolates were closely related with >99% sequence identity, whereas the Chinese isolate was more distantly related. We identified two loci that may be associated with the fast action of the SpltNPV-Pak-TAX1 isolate. First, an analysis of rates of synonymous and non-synonymous mutations identified neutral to positive selection on open reading frame (ORF) 122, encoding a viral fibroblast growth factor (vFGF) that is known to affect virulence in other baculoviruses. Second, the homologous repeat region hr17, a putative enhancer of transcription and origin of replication, is absent in SpltNPV-Pak-TAX1 suggesting it may also affect virulence. Additionally, we found there is little genetic variation within both Pakistani isolates, and we identified four genes under positive selection in both isolates that may have played a role in adaptation of SpltNPV to conditions in Central Asia. Our results contribute to the understanding of the enhanced activity of SpltNPV-Pak-TAX1, and may help to select better SpltNPV isolates for the control of S. litura in Pakistan and elsewhere.
50
Zhu, Yu Cheng, and Quentin Q. Fang. "The phylogenetic relationships of introducedAphelinus(Hymenoptera: Aphelinidae), biological control agents of the Russian wheat aphid (Homoptera: Aphididae)." Insect Science 16, no. 3 (June 2009): 277–85. http://dx.doi.org/10.1111/j.1744-7917.2009.01249.x.
Full text