Aydin Yesilyurt

Bio: Aydin Yesilyurt is an academic researcher from Karadeniz Technical University. The author has contributed to research in topics: Open reading frame & Medicine. The author has an hindex of 2, co-authored 6 publications receiving 14 citations.

Chilo iridescent virus encodes two functional metalloproteases

Abstract: The genome of Chilo iridescent virus (CIV) has two open reading frames (ORFs) with matrix metalloprotease (MMP) domains. The protein encoded by ORF 136R contains 178 amino acids with over 40% amino acid sequence identity to hypothetical metalloproteases of other viruses, and the protein 165R contains 264 amino acids with over 40% amino acid sequence identity to metalloproteases of a large group of organisms, primarily including a variety of Drosophila species. These proteins possess conserved zinc-binding motifs in their catalytic domains. In this study, we focused on the functional analysis of these ORFs. They were cloned into the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) Bac-to-Bac baculovirus expression-vector system, expressed in insect Sf9 cells with an N-terminal His tag, and purified to homogeneity at 72 hours postinfection using Ni-NTA affinity chromatography. Western blot analyses of purified 136R and 165R proteins with histidine tags resulted in 24- and 34-kDa protein bands, respectively. Biochemical assays with the purified proteins, performed using azocoll and azocasein as substrates, showed that both proteins have protease activity. The enzymatic activities were inhibited by the metalloprotease inhibitor EDTA. Effects of these proteins were also investigated on Galleria mellonella larvae. Insecticidal activity was tested by injecting the larvae with the virus derived from the AcMNPV bacmid carrying 136R or 165R ORFs. The results showed that the baculoviruses harbouring the iridoviral metalloproteases caused early death of the larvae compared to control group. These data suggest that the CIV 136R and 165R ORFs encode functional metalloproteases. This study expands our knowledge about iridoviruses, describes the characterization of CIV matrix metalloproteinases, and might ultimately contribute to the use of this virus as a research tool.

Comparison of the potential activities of viral and bacterial chitinases

Abstract: Chitin, a long-chain polymer of N-acetylglucosamine, is a major structural component of the insect exoskeleton and the peritrophic membrane (PM). Chitinases are able to effectively break down glycosidic bonds of chitin polymer thus can be used in agriculture to control plant pathogen insects. These enzymes can be synthesized by higher plants, animals, protista, bacteria, and viruses. In this study, viral and bacterial chitinases were compared for their potential activity on a laboratory test insect. The genes encoding chitinases of Autographa californica nucleopolyhedrovirus (AcNPV) and Cydia pomonella granulovirus (CpGV) were amplified from genomic DNAs by PCR and cloned into the pET-28a (+) expression vector. The chitinase proteins of these 2 viruses (AcNPV-Chi, CpGV-Chi) and Serratia marcescens chitinase C (ChiC) protein which was previously cloned were overexpressed in Escherichia coli. Expressed proteins were purified and confirmed by western blot analysis as 50, 63, and 68 kDa for AcNPV, CpGV, and S. marcescens chitinases, respectively. Enzyme activities of the chitinases were confirmed. Chitinases were also compared to each other in silico. The insecticidal effects of these proteins were evaluated on Galleria mellonella L. larvae. Bioassays were performed on the 3rd instar larvae for each chitinase protein in triplicate. The results showed that although there were differences in enzymatic activities and domain organizations, all 3 microbial chitinases produced almost the same level of insecticidal activity on the test insect. LC50 and LT50 values were compatible with the mortality results. These results were a preanalysis for comparing the effects of microbial chitinases. Potential activity experiments should be carried out on more insects to provide detailed information on the insecticidal effects of bacterial and viral chitinases.

Insecticidal activities of wild type and recombinant invertebrate iridescent viruses on five common pests

Abstract: Omurgasiz iridesan virus 6 (IIV6), cesitli zararli bocek turlerini dusuk oranda enfekte edebilir. Rekombinant DNA teknolojisi ile olusturulan yeni ozelliklere sahip virusler biyolojik kontrol ajanlari olarak etkin bir sekilde kullanilabilir. Daha once IIV6 157L ORF’si yerine birisi yesil floresan protein geni (rCIV-Δ157L-gfp) ve digeri de gfp ile birlestirilmis bir akrep Androctonus australis (Linnaeus, 1758) bocek toksin geni (rCIV-Δ157L/gfp-AaIT) ihtiva eden iki rekombinant IIV6 insa edilmisti. Bu calismada, yaban tip IIV6 ve iki rekombinant virus, Helicoverpa armigera (Hubner, 1805) (Lepidoptera: Noctuidae), Spodoptera littoralis (Boisduval, 1883) (Lepidoptera: Noctuidae), Lymantria dispar (Linnaeus, 1758) (Lepidoptera: Erebidae), Euproctis chrysorrhoea (Linnaeus, 1758) (Lepidoptera: Erebidae) ve Tenebrio molitor (Linnaeus, 1758) (Coleoptera: ‎Tenebrionidae) larvalarinda enfeksiyon olusturma yetenegi acisindan degerlendirildi. Calisma 2018 ve 2019 yillari arasinda Karadeniz Teknik Universitesi Biyoloji Bolumu'nde gerceklestirildi. Her bir bocek larvasini enjekte etmek icin viruslerin bes farkli konsantrasyonu (103, 104, 105, 106 ve107 TCID50/ml) kullanildi. rCIV-Δ157L/gfp-AaIT ile enfekte olmus S. littoralis disinda tum larvalar felc oldu. rCIV-Δ157L/gfp-AaIT ile enfekte olmus bocek larvalarinin LC50'si sirasiyla, S. littoralis , T. molitor , L. dispar , H. armigera ve E. chrysorrhoea uzerinde 0.3 x 107, 0.7 x 105, 0.2 x 105, 0.15 x 105, 0.7 x 104 TCID50/ml olarak belirlenmistir. En yuksek virus konsantrasyonlarina gore hesaplanan LT50 degerleri, rCIV-Δ157L/gfp-AaIT icin S. littoralis , T. molitor , L. dispar , H. armigera ve E. chrysorrhoea 'da sirasiyla 10.5, 6.2, 4.7, 7.5 ve 5 gun olarak bulundu. Bu calisma, rekombinant IIV6'nin Lepidoptera ve Coleoptera takimlarina ait bazi boceklerde patojeniteyi artirdigini gostermistir.

Characterization of a novel baculovirus isolate from Malacosoma neustria (Linnaeus, 1758) (Lepidoptera: Lasiocampidae) in Samsun and its pathogenicity in different hosts

Abstract: Malacosoma neustria (Linnaeus, 1758) (Lepidoptera: Lasiocampidae) causes economic losses in apple, pear, plum, willow, oak and other economically important trees. In this study, an alphabaculovirus was isolated from the larval population of M. neustria from Samsun in the central Black Sea Region of Turkey between 2015 and 2016. Electron microscope analysis of occlusion bodies (OBs) obtained from dead larvae showed that the nucleocapsids of a new isolate (ManeNPV-T4) are multiply enveloped. The Kimura two-parameter analysis and the phylogenetic tree were performed based on concatenated nucleotide and amino acid sequences of the partial lef-8, lef-9 and polh genes from ManeNPV-T4 isolate compared to those of other 51 baculoviruses. Insecticidal activity tests against third instar M. neustria larvae produced 48 to 100% mortalities. The LC 50 of ManeNPV-T4 was 0.78 x 10 3 OBs/ml in M. neustria . Additionally, the isolate caused mortalities lower than 50% in Spodoptera exigua (Hubner, 1808) (Lepidoptera: Noctuidae) , Lymantria dispar (Linnaeus, 1758) (Lepidoptera: Erebidae) , Hyphantria cunea (Drury, 1773) (Lepidoptera: Arctiidae) and Helicoverpa armigera (Hubner, 1805) (Lepidoptera: Noctuidae) larvae. Consequently, the new nucleopolyhedrovirus is infectious on M. neustria larvae and other lepidopterans.

Invertebrate Iridoviruses: A Glance over the Last Decade.

Abstract: Members of the family Iridoviridae (iridovirids) are large dsDNA viruses that infect both invertebrate and vertebrate ectotherms and whose symptoms range in severity from minor reductions in host fitness to systemic disease and large-scale mortality. Several characteristics have been useful for classifying iridoviruses; however, novel strains are continuously being discovered and, in many cases, reliable classification has been challenging. Further impeding classification, invertebrate iridoviruses (IIVs) can occasionally infect vertebrates; thus, host range is often not a useful criterion for classification. In this review, we discuss the current classification of iridovirids, focusing on genomic and structural features that distinguish vertebrate and invertebrate iridovirids and viral factors linked to host interactions in IIV6 (Invertebrate iridescent virus 6). In addition, we show for the first time how complete genome sequences of viral isolates can be leveraged to improve classification of new iridovirid isolates and resolve ambiguous relations. Improved classification of the iridoviruses may facilitate the identification of genus-specific virulence factors linked with diverse host phenotypes and host interactions.

Detection and Characterization of Invertebrate Iridoviruses Found in Reptiles and Prey Insects in Europe over the Past Two Decades.

Abstract: Invertebrate iridoviruses (IIVs), while mostly described in a wide range of invertebrate hosts, have also been repeatedly detected in diagnostic samples from poikilothermic vertebrates including reptiles and amphibians. Since iridoviruses from invertebrate and vertebrate hosts differ strongly from one another based not only on host range but also on molecular characteristics, a series of molecular studies and bioassays were performed to characterize and compare IIVs from various hosts and evaluate their ability to infect a vertebrate host. Eight IIV isolates from reptilian and orthopteran hosts collected over a period of six years were partially sequenced. Comparison of eight genome portions (total over 14 kbp) showed that these were all very similar to one another and to an earlier described cricket IIV isolate, thus they were given the collective name lizard–cricket IV (Liz–CrIV). One isolate from a chameleon was also subjected to Illumina sequencing and almost the entire genomic sequence was obtained. Comparison of this longer genome sequence showed several differences to the most closely related IIV, Invertebrate iridovirus 6 (IIV6), the type species of the genus Iridovirus, including several deletions and possible recombination sites, as well as insertions of genes of non-iridoviral origin. Three isolates from vertebrate and invertebrate hosts were also used for comparative studies on pathogenicity in crickets (Gryllus bimaculatus) at 20 and 30 °C. Finally, the chameleon isolate used for the genome sequencing studies was also used in a transmission study with bearded dragons. The transmission studies showed large variability in virus replication and pathogenicity of the three tested viruses in crickets at the two temperatures. In the infection study with bearded dragons, lizards inoculated with a Liz–CrIV did not become ill, but the virus was detected in numerous tissues by qPCR and was also isolated in cell culture from several tissues. Highest viral loads were measured in the gastro-intestinal organs and in the skin. These studies demonstrate that Liz–CrIV circulates in the pet trade in Europe. This virus is capable of infecting both invertebrates and poikilothermic vertebrates, although its involvement in disease in the latter has not been proven.

Baculovirus enhancins and their role in viral pathogenicity. Chapter 9

Abstract: Baculoviruses are a large group of viruses pathogenic to arthropods, primarily insects from the order Lepidoptera and also insects in the orders Hymenoptera and Diptera. Baculoviruses have been used to control insect pests on agricultural crops and forests around the world. Efforts have been ongoing for the last two decades to develop strains of baculoviruses with greater potency or other attributes to decrease the cost of their use through a lower cost of production or application. Early efforts focused on the insertion of foreign genes into the genomes of baculoviruses that would increase viral killing speed for use to control agricultural insect pests. More recently, research efforts have focused on viral genes that are involved in the initial and early processes of infection and host factors that impede successful infection. The enhancins are proteins produced by some baculoviruses that are involved in one of the earliest events of host infection. This article provides a review of baculovirus enhancins and their role in the earliest phases of viral infection.

Application of the Scorpion Neurotoxin AaIT against Insect Pests.

Abstract: Androctonus australis Hector insect toxin (AaIT), an insect-selective toxin, was identified in the venom of the scorpion Androctonus australis. The exclusive and specific target of the toxin is the voltage-gated sodium channels of the insect, resulting in fast excitatory paralysis and even death. Because of its strict toxic selectivity and high bioactivity, AaIT has been widely used in experiments exploring pest bio-control. Recombinant expression of AaIT in a baculovirus or a fungus can increase their virulence to insect pests and diseases vectors. Likewise, transgenic plants expressing AaIT have notable anti-insect activity. AaIT is an efficient toxin and has great potential to be used in the development of commercial insecticides.

A Systematic Review on Viruses in Mass-Reared Edible Insect Species.

Abstract: Edible insects are expected to become an important nutrient source for animals and humans in the Western world in the near future. Only a few studies on viruses in edible insects with potential for industrial rearing have been published and concern only some edible insect species. Viral pathogens that can infect insects could be non-pathogenic, or pathogenic to the insects themselves, or to humans and animals. The objective of this systematic review is to provide an overview of the viruses detected in edible insects currently considered for use in food and/or feed in the European Union or appropriate for mass rearing, and to collect information on clinical symptoms in insects and on the vector role of insects themselves. Many different virus species have been detected in edible insect species showing promise for mass production systems. These viruses could be a risk for mass insect rearing systems causing acute high mortality, a drastic decline in growth in juvenile stages and in the reproductive performance of adults. Furthermore, some viruses could pose a risk to human and animal health where insects are used for food and feed.