Papers by ikbal Agah iNCE
BMC Microbiology, 2018
With the absence of effective prophylactic vaccines and drugs against African trypanosomosis, con... more With the absence of effective prophylactic vaccines and drugs against African trypanosomosis, control of this group of zoonotic neglected tropical diseases depends the control of the tsetse fly vector. When applied in an area-wide insect pest management approach, the sterile insect technique (SIT) is effective in eliminating single tsetse species from isolated populations. The need to enhance the effectiveness of SIT led to the concept of investigating tsetse-trypanosome interactions by a consortium of researchers in a five-year (2013–2018) Coordinated Research Project (CRP) organized by the Joint Division of FAO/IAEA. The goal of this CRP was to elucidate tsetse-symbiome-pathogen molecular interactions to improve SIT and SIT-compatible interventions for trypanosomoses control by enhancing vector refractoriness. This would allow extension of SIT into areas with potential disease transmission. This paper highlights the CRP's major achievements and discusses the science-based perspectives for successful mitigation or eradication of African trypanosomosis.
Frontiers in Microbiology, 2018
The Glossina pallidipes salivary gland hypertrophy virus (GpSGHV) infects tsetse flies predominan... more The Glossina pallidipes salivary gland hypertrophy virus (GpSGHV) infects tsetse flies predominantly asymptomatically and occasionally symptomatically. Symptomatic infections are characterized by overt salivary gland hypertrophy (SGH) in mass reared tsetse flies, which causes reproductive dysfunctions and colony collapse, thus hindering tsetse control via sterile insect technique (SIT). Asymptomatic infections have no apparent cost to the fly's fitness. Here, small RNAs were sequenced and profiles in asymptomatically and symptomatically infected G. pallidipes flies determined. Thirty-eight host-encoded microRNAs (miRNAs) were present in both the asymptomatic and symptomatic fly profiles, while nine host miRNAs were expressed specifically in asymptomatic flies versus 10 in symptomatic flies. Of the shared 38 miRNAs, 15 were differentially expressed when comparing asymptomatic with symptomatic flies. The most up-regulated host miRNAs in symptomatic flies was predicted to target immune-related mRNAs of the host. Six GpSGHV-encoded miRNAs were identified, of which five of them were only in symptomatic flies. These virus-encoded miRNAs may not only target host immune genes but may also participate in viral immune evasion. This evidence of differential host miRNA profile in Glossina in symptomatic flies advances our understanding of the GpSGHV-Glossina interactions and provides potential new avenues, for instance by utilization of particular miRNA inhibitors or mimics to better manage GpSGHV infections in tsetse mass-rearing facilities, a prerequisite for successful SIT implementation.
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY (IJSEM)
A Gram positive, rod shaped, facultatively oligotrophic bacterial strain, designated MB18T, was i... more A Gram positive, rod shaped, facultatively oligotrophic bacterial strain, designated MB18T, was isolated from a water sample collected from River Mahananda at Siliguri (26°44'23.20"N, 88°25'22.89"E), West Bengal, India. On the basis of 16S rRNA gene sequence similarity, the closest relative of this strain was Brevibacterium epidermidis NCDO 2286T (96% similarity). The DNA G+C content of strain MB18T was 64.6 mol%. Chemotaxonomic data [Mk-8(H2) as major major menaquinone, galac-tose as sole cell wall sugar, meso-diaminopimelic acid as diagnostic cell wall diamino acid, phosphatidylglycerol (PG) and diphosphatidylglycerol (DPG) as constituents of polar lipids, anteiso-C15: 0 , anteiso-C17: 0 and iso-C15:0 as the major fatty acids] supported the affiliation of strain MB18T to the genus Brevibacterium. The results of DNA G + C content, 16S rRNA gene sequence analysis, biochemical and physiological analyses allowed genotypic and phenotypic differentiation of strain MB18T from its nearest neighbour B. epidermidis. The isolate, therefore represents a new species, for which the name Brevibacterium siliguriense sp. nov. is proposed, with the type strain is MB18T (=DSM 23676T = LMG 25772T).
Glossina pallidipes salivary gland hypertrophy virus (GpSGHV; family Hytrosaviridae) is a dsDNA v... more Glossina pallidipes salivary gland hypertrophy virus (GpSGHV; family Hytrosaviridae) is a dsDNA virus exclusively pathogenic to tsetse flies (Diptera; Glossinidae). The 190 kb GpSGHV genome contains 160 open reading frames and encodes more than 60 confirmed proteins. The asymptomatic GpSGHV infection in flies can convert to symptomatic infection that is characterized by overt salivary gland hypertrophy (SGH). Flies with SGH show reduced general fitness and reproductive dysfunction. Although the occurrence of SGH is an exception rather than the rule, G. pallidipes is thought to be the most susceptible to expression of overt SGH symptoms compared to other Glossina species that are largely asymptomatic. Although Glossina salivary glands (SGs) play an essential role in GpSGHV transmission, the functions of the salivary components during the virus infection are poorly understood. In this study, we used mass spectrometry to study SG proteomes of G. pallidipes and G. m. morsitans, two Glossina model species that exhibit differential GpSGHV pathologies (high and low incidence of SGH, respectively). A total of 540 host proteins were identified, of which 23 and 9 proteins were significantly up- and down-regulated, respectively, in G. pallidipes compared to G. m. morsitans. Whereas 58 GpSGHV proteins were detected in G. pallidipes F1 progenies, only 5 viral proteins were detected in G. m. morsitans. Unlike in G. pallidipes, qPCR assay did not show any significant increase in virus titers in G. m. morsitans F1 progenies, confirming that G. m. morsitans is less susceptible to GpSGHV infection and replication compared to G. pallidipes. Based on our results, we speculate that in the case of G. pallidipes, GpSGHV employs a repertoire of host intracellular signaling pathways for successful infection. In the case of G. m. morsitans, antiviral responses appeared to be dominant. These results are useful for designing additional tools to investigate the Glossina-GpSGHV interactions.
Journal of General Virology, 2014
Invertebrate iridescent virus 6 (IIV-6) is a nucleocytoplasmic virus with a ~212 kb linear dsDNA ... more Invertebrate iridescent virus 6 (IIV-6) is a nucleocytoplasmic virus with a ~212 kb linear dsDNA genome that encodes 215 putative ORFs. The IIV-6 virion-associated proteins consist of at least 54 virally encoded proteins. One of our previous findings showed that most of these proteins are encoded by genes from the early transcriptional class. This indicated that these structural proteins may not only function in the formation of the virion, but also in the initial stage of viral infection. In the current study, we followed the protein expression profile of IIV-6 over time in Drosophila S2 cells by label-free quantification using a proteomic approach. A total of 95 virally encoded proteins were detected in infected cells, of which 37 were virion proteins. The expressed IIV-6 virion proteins could be categorized into three main clusters based on their expression profiles: proteins with stably low expression levels during infection, proteins with exponentially increasing expression levels during infection and proteins that were initially highly abundant, but showed slightly reduced levels after 48 h post-infection. We thus provided novel information on the kinetics of virion and infected cell-specific protein levels that assists in our understanding of gene regulation in this lesser-known DNA virus model.
The Glossina pallidipes salivary gland hypertrophy virus (GpSGHV) is a dsDNA virus with rodshaped... more The Glossina pallidipes salivary gland hypertrophy virus (GpSGHV) is a dsDNA virus with rodshaped, enveloped virions. Its 190 kb genome contains 160 putative protein-coding ORFs. Here, the structural components, protein composition and associated aspects of GpSGHV morphogenesis and cytopathology were investigated. Four morphologically distinct structures: the nucleocapsid, tegument, envelope and helical surface projections, were observed in purified GpSGHV virions by electron microscopy. Nucleocapsids were present in virogenic stroma within the nuclei of infected salivary gland cells, whereas enveloped virions were located in the cytoplasm. The cytoplasm of infected cells appeared disordered and the plasma membranes disintegrated. Treatment of virions with 1 % NP-40 efficiently partitioned the virions into envelope and nucleocapsid fractions. The fractions were separated by SDS-PAGE followed by in-gel trypsin digestion and analysis of the tryptic peptides by liquid chromatography coupled to electrospray and tandem mass spectrometry. Using the MaxQuant program with Andromeda as a database search engine, a total of 45 viral proteins were identified. Of these, ten and 15 were associated with the envelope and the nucleocapsid fractions, respectively, whilst 20 were detected in both fractions, most likely representing tegument proteins. In addition, 51 host-derived proteins were identified in the proteome of the virus particle, 13 of which were verified to be incorporated into the mature virion using a proteinase K protection assay. This study provides important information about GpSGHV biology and suggests options for the development of future anti-GpSGHV strategies by interfering with virus-host interactions.
Many species of tsetse flies (Diptera: Glossinidae) can be infected by a virus that causes saliva... more Many species of tsetse flies (Diptera: Glossinidae) can be infected by a virus that causes salivary gland hypertrophy (SGH). The genomes of viruses isolated from Glossina pallidipes (GpSGHV) and Musca domestica (MdSGHV) have recently been sequenced. Tsetse flies with SGH have reduced fecundity and fertility which cause a serious problem for mass rearing in the frame of sterile insect technique (SIT) programmes to control and eradicate tsetse populations in the wild. A potential intervention strategy to mitigate viral infections in fly colonies is neutralizing of the GpSGHV infection with specific antibodies against virion proteins. Two major GpSGHV virion proteins of about 130 and 50 kDa, respectively, were identified by Western analysis using a polyclonal rabbit antibody raised against whole GpSHGV virions. The proteome of GpSGHV, containing the antigens responsible for the immune-response, was investigated by liquid chromatography tandem mass spectrometry and 61 virion proteins were identified by comparison with the genome sequence. Specific antibodies were produced in rabbits against seven candidate proteins, including the ORF10/C-terminal fragment, ORF47 and ORF96 as well as proteins involved in peroral infectivity PIF-1 (ORF102), PIF-2 (ORF53), PIF-3 (ORF76) and P74 (ORF1). Antiserum against ORF10 specifically reacted to the 130 kDa protein in a Western blot analysis and to the envelope protein of GpSGHV, detected by using immunogold-electron microscopy. This result suggests that immune intervention of viral infections in colonies of G. pallidipes is a realistic option.
Journal of General Virology, 2010
Many species of tsetse flies (Diptera: Glossinidae) can be infected by a virus that causes saliva... more Many species of tsetse flies (Diptera: Glossinidae) can be infected by a virus that causes salivary gland hypertrophy (SGH). The genomes of viruses isolated from Glossina pallidipes (GpSGHV) and Musca domestica (MdSGHV) have recently been sequenced. Tsetse flies with SGH have reduced fecundity and fertility which cause a serious problem for mass rearing in the frame of sterile insect technique (SIT) programmes to control and eradicate tsetse populations in the wild. A potential intervention strategy to mitigate viral infections in fly colonies is neutralizing of the GpSGHV infection with specific antibodies against virion proteins. Two major GpSGHV virion proteins of about 130 and 50 kDa, respectively, were identified by Western analysis using a polyclonal rabbit antibody raised against whole GpSHGV virions. The proteome of GpSGHV, containing the antigens responsible for the immune-response, was investigated by liquid chromatography tandem mass spectrometry and 61 virion proteins were identified by comparison with the genome sequence. Specific antibodies were produced in rabbits against seven candidate proteins, including the ORF10/C-terminal fragment, ORF47 and ORF96 as well as proteins involved in peroral infectivity PIF-1 (ORF102), PIF-2 (ORF53), PIF-3 (ORF76) and P74 (ORF1). Antiserum against ORF10 specifically reacted to the 130 kDa protein in a Western blot analysis and to the envelope protein of GpSGHV, detected by using immunogold-electron microscopy. This result suggests that immune intervention of viral infections in colonies of G. pallidipes is a realistic option.
Abstract RNA viruses in insects are targets of an RNA interference (RNAi)-based antiviral immune ... more Abstract RNA viruses in insects are targets of an RNA interference (RNAi)-based antiviral immune response, in which viral replication intermediates or viral dsRNA genomes are processed by Dicer-2 (Dcr-2) into viral small interfering RNAs (vsiRNAs). Whether dsDNA virus infections are controlled by the RNAi pathway remains to be determined. Here, we analyzed the role of RNAi in DNA virus infection using Drosophila melanogaster infected with Invertebrate iridescent virus 6 (IIV-6) as a model.
Background The competence of the tsetse fly Glossina pallidipes (Diptera; Glossinidae) to acquire... more Background The competence of the tsetse fly Glossina pallidipes (Diptera; Glossinidae) to acquire salivary gland hypertrophy virus (SGHV), to support virus replication and successfully transmit the virus depends on complex interactions between Glossina and SGHV macromolecules. Critical requisites to SGHV transmission are its replication and secretion of mature virions into the fly's salivary gland (SG) lumen.
Journal of microbiology …, Jan 1, 2007
A cytoplasmic polyhedrosis virus (CPV) was isolated from the larvae of Thaumetopoea pityocampa an... more A cytoplasmic polyhedrosis virus (CPV) was isolated from the larvae of Thaumetopoea pityocampa and shown to cause an infection of midgut cells. This viral infection revealed several important diagnostic symptoms, including discoloration of the posterior midgut, reduced feeding, and extended development time of the larvae. The virus infection is lethal to Thaumetopoea pityocampa, and with the increasing doses kills the larvae within 4-5 days post infection. Electron microscopy studies showed typical cytoplasmic polyhedral ...
Glacial ice traps and preserves soluble chemical species, gases and particulates including pollen... more Glacial ice traps and preserves soluble chemical species, gases and particulates including pollen grains, fungal spores and bacteria in chronologically-deposited archives. We have constructed an ice-core sampling system that melts ice only from the interior of cores, thereby avoiding surface contamination, and using this system we have isolated, cultured and characterized bacteria from ice cores that range from 5 to 20,000 years in age and that originating from both polar and non-polar regions. Low-latitude, high-altitude non-polar ice cores generally contain more culturable bacteria than polar ices, consistent with closer proximities to major biological ecosystems. Direct plating of melt-water from a 200-year old sample of ice from the Guliya ice cap on the Tibetan Plateau (China) generated ~180 bacterial colonies per ml [colony forming units/ml; (cfu/ml)], whereas melt water from late Holocene ice from Taylor Dome in Antarctica contained only 10 cfu/ml, and <10 cfu/ml were present ice of the same age from the Antarctic Peninsula and from Greenland. Based on their small-subunit ribosomal RNA-encoding DNA (rDNA) sequences many, but not all of the bacteria isolated are spore-forming species belong to Bacillus and Actinomycete genera. Non-chronological fluctuations are observed in the numbers of bacteria present, consistent with episodic deposition resulting from attachment to larger particulates.
CITATIONS 25 READS 22 5 authors, including: Some of the authors of this publication are also work... more CITATIONS 25 READS 22 5 authors, including: Some of the authors of this publication are also working on these related projects: -Detection of pathogen signals in complex biological samples using well established model organisms (in Human, Drosophila, Tsetse). View project Ikbal Agah Ince Acibadem Üniversitesi
Many species of tsetse flies (Diptera: Glossinidae) can be infected by a virus that causes saliva... more Many species of tsetse flies (Diptera: Glossinidae) can be infected by a virus that causes salivary gland hypertrophy (SGH). The genomes of viruses isolated from Glossina pallidipes (GpSGHV) and Musca domestica (MdSGHV) have recently been sequenced. Tsetse flies with SGH have reduced fecundity and fertility which cause a serious problem for mass rearing in the frame of sterile insect technique (SIT) programmes to control and eradicate tsetse populations in the wild. A potential intervention strategy to mitigate viral infections in fly colonies is neutralizing of the GpSGHV infection with specific antibodies against virion proteins. Two major GpSGHV virion proteins of about 130 and 50 kDa, respectively, were identified by Western analysis using a polyclonal rabbit antibody raised against whole GpSHGV virions. The proteome of GpSGHV, containing the antigens responsible for the immune-response, was investigated by liquid chromatography tandem mass spectrometry and 61 virion proteins were identified by comparison with the genome sequence. Specific antibodies were produced in rabbits against seven candidate proteins, including the ORF10/C-terminal fragment, ORF47 and ORF96 as well as proteins involved in peroral infectivity PIF-1 (ORF102), PIF-2 (ORF53), PIF-3 (ORF76) and P74 (ORF1). Antiserum against ORF10 specifically reacted to the 130 kDa protein in a Western blot analysis and to the envelope protein of GpSGHV, detected by using immunogold-electron microscopy. This result suggests that immune intervention of viral infections in colonies of G. pallidipes is a realistic option.
Biocontrol Science and …, Jan 1, 2009
The entomopathogenic bacterium Bacillus thuringiensis (Bt) is the most widely used biopesticide. ... more The entomopathogenic bacterium Bacillus thuringiensis (Bt) is the most widely used biopesticide. The specific toxic activity to insects and other organisms is related to the presence of crystals that have different morphologies, sizes, numbers and compositions according to the Bt strain. The crystals contain different proteins, which are encoded by distinct cry (crystal) genes. In this work, we have characterized two novel Bt strains isolated from the soils of south Brazil (named UNI498 and UNI872) and determined the lethal concentrations (LC 50 ) of their crystal proteins to Anticarsia gemmatalis larvae. Serotyping of the new isolates was performed and the results indicated that UNI872 is a Bt serovar kurstaki and UNI498 is a Bt serovar aizawai. By transmission electron microscopy, we observed that UNI498 has crystals with cubic morphology whereas UNI872 has crystals with a bipyramidal shape. Polymerase chain reactions (PCRs) revealed the presence of cry1-like sequences in both isolates and a cry2-like gene in UNI 872. The cry1 fragments were sequenced and showed identities of 96 and 97% to known cry1A genes (UNI872 and UNI498, respectively). The presence of Cry1 proteins in both isolates was confirmed by SDS-PAGE. Bioassays to determine the LC 50 were performed with A. gemmatalis third instar larvae using purified proteins. Results showed LC 50 s of 1:69 ng=cm 2 for UNI498 and 0:49 ng=cm 2 for UNI872. Ó
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Papers by ikbal Agah iNCE