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Fulltext Living with marginal coral communities: Diversity and host-specificity in coral-associated barnacles in the northern coral distribution limit of the East China Sea

Chan BKK, Xu G, Kim HK, Park JH, Kim W

PLoS One, 2018;13(5):e0196309.
PMID: 29715264 DOI: 10.1371/journal.pone.0196309

Corals and their associated fauna are extremely diverse in tropical waters and form major reefs. In the high-latitude temperate zone, corals living near their distribution limit are considered marginal communities because they are particularly extremely sensitive to environmental and climatic changes. In this study, we examined the diversity and host usage of coral-associated barnacles on Jeju Island, Korea, the northern coral distribution limit in the East China Sea. In this study, only three coral-associated barnacles-from two genera in two subfamilies-were collected. The Pyrgomatinid barnacles Cantellius arcuatus and Cantellius cf. euspinulosum were found only on the corals Montipora millepora and Alveopora japonica, respectively. The Megatrematinid barnacle Pyrgomina oulastreae, relatively a generalist, was found on Psammocora spp. (both profundacella and albopicta) and Oulastrea crispata corals. The host usage of these three barnacles does not overlap. DNA barcode sequences of the C. arcuatus specimens collected in the present study matched those collected in Kochi in Japan, Taiwan, Malaysia and Papua New Guinea, suggesting that this species has a wide geographical distribution. C. arcuatus covers a wider host range in Taiwan waters, inhabiting Montipora spp. and Porites spp., which suggests that the host specificity of coral-associated barnacles varies with host availability. C. cf. euspinulosum probably has a very narrow distribution and host usage. The sequences of C. cf. euspinulosum on Jeju Island do not match those of any known sequences of Cantellius barnacles in the Indo-Pacific region. P. oulastreae probably prefers cold water because it has been reported in temperate regions. Coral-associated barnacles in marginal communities have considerably lower diversity than their subtropical and tropical counterparts. When host availability is limited, marginal coral-associated barnacles exhibit higher host specificity than those in subtropical and tropical reef systems.

Matched MeSH terms: Host Specificity*
Fulltext Predicting the potential for zoonotic transmission and host associations for novel viruses

Pandit PS, Anthony SJ, Goldstein T, Olival KJ, Doyle MM, Gardner NR, et al.

Commun Biol, 2022 Aug 19;5(1):844.
PMID: 35986178 DOI: 10.1038/s42003-022-03797-9

Host-virus associations have co-evolved under ecological and evolutionary selection pressures that shape cross-species transmission and spillover to humans. Observed virus-host associations provide relevant context for newly discovered wildlife viruses to assess knowledge gaps in host-range and estimate pathways for potential human infection. Using models to predict virus-host networks, we predicted the likelihood of humans as hosts for 513 newly discovered viruses detected by large-scale wildlife surveillance at high-risk animal-human interfaces in Africa, Asia, and Latin America. Predictions indicated that novel coronaviruses are likely to infect a greater number of host species than viruses from other families. Our models further characterize novel viruses through prioritization scores and directly inform surveillance targets to identify host ranges for newly discovered viruses.

Matched MeSH terms: Host Specificity
Fulltext Host specificity and adaptive evolution in settlement behaviour of coral-associated barnacle larvae (Cirripedia: Pyrgomatidae)

Yap FC, Chen HN, Chan BKK

Sci Rep, 2023 Jun 14;13(1):9668.
PMID: 37316644 DOI: 10.1038/s41598-023-33738-3

Coral-associated organisms often exhibit a continuum of host specificities. We do not know whether the variation in host specificity is related to the settlement organs or preferential settlement behaviours of the larvae. We examined the morphology of attachment discs, the settlement and metamorphosis of coral barnacles-Pyrgoma cancellatum (lives in a single coral species), Nobia grandis (two families of corals), and Armatobalanus allium (six families of corals). Our results revealed that the attachment organ of all three species are spear-shaped with sparse villi, indicating that the morphology of the attachment organs does not vary among species with different host specificities. Larvae of P. cancellatum and N. grandis only settle on their specific hosts, suggesting that chemical cues are involved in the settlement. Cyprids of N. grandis display close searching behaviour before settlement. Cyprids of P. cancellatum settle immediately on their specific host corals, without any exploratory behaviour. The host specificity and exploratory behaviours of coral barnacle cyprids are results of adaptive evolution. We argue that there is a trade-off between exploration and energy conservation for metamorphosis processes. Coral barnacle metamorphosis is longer when compared to free-living species, likely because it involves the development of a tube-shaped base on the coral surface.

Matched MeSH terms: Host Specificity
Fulltext Molecular phylogeny and genetic diversity of Fusarium oxysporum from various hosts in Malaysia

Mohd-Hafifi AB, Mohamed Nor NMI, Zakaria L, Mohd MH

Sci Rep, 2024 Nov 29;14(1):29708.
PMID: 39613784 DOI: 10.1038/s41598-024-78195-8

Fusarium oxysporum is a cosmopolitan fungus, consisting of both pathogenic and non-pathogenic members and known to be the causative agent of several diseases on various host plants. In Malaysia, most studies have focused on pathogenic F. oxysporum isolates because of their implications for agricultural production, but less attention has been given to non-pathogenic isolates. The aim of this study was to determine the phylogenetic relationship, genetic diversity, pathogenicity and host range of F. oxysporum in Malaysia. A total of 133 isolates of F. oxysporum were isolated from symptomatic plants of Abelmoschus esculentus, Solanum melongena, Solanum tuberosum, Cucumis sativus, Solanum lycopersicum, Cucumis melo, Musa paradisiaca var. awak, Hymenocallis littoralis, Asparagus officinalis, and Sansevieria trifasciata and non-agricultural soils in Malaysia. Comparison of nucleotide sequences of translation elongation factor 1-alpha (tef1-α) and mitochondrial small subunit (mtSSU) showed that the isolates were 98-100% similar to F. oxysporum from GenBank, thus, confirming the fungal identity. Besides, Malaysian isolates of F. oxysporum exhibited polyphyletic evolutionary origin, wide host range, and genetically diverse by grouping into 20 VCGs and 17 IGS haplotypes. This finding is beneficial for the purpose of quarantine, monitoring and disease management in the agricultural settings in Malaysia.

Matched MeSH terms: Host Specificity
Fulltext Isolation and characterization of bacteriophage against clinical isolates of AmpC beta lactamase-Producing Klebsiella pneumoniae from hospital wastewater

Abusalah MAHA, Abusalah MAHA, Yean Yean C, Aziah I, Zaidah AR

PLoS One, 2025;20(2):e0315079.
PMID: 39982880 DOI: 10.1371/journal.pone.0315079

BACKGROUND: The increasing incidence of AmpC β-lactamase producing by K. pneumoniae has raised global alarm. Consequently, there is a crucial need for effective methods to inactivate pathogenic bacteria and mitigate the associated risks. Bacteriophage therapy has been demonstrated to be an effective and alternative approach for targeting and inactivating K. pneumoniae that produces AmpC. This study aimed to isolate and characterize the Klebsiella pneumoniae AmpC-specific phages from hospital wastewater.
METHODS: The hospital wastewater samples were collected from the sewage water effluent of a tertiary hospital at Universiti Sains Malaysia, located on the east coast of Malaysia. These samples underwent serial filtration and centrifugation processes for phage recovery. The phage solutions were undergoing a screening test by spot assay using clinical isolates of Klebsiella pneumoniae AmpC strain as amplification hosts. The isolated AmpC-phages were further studied and characterised to determine the phage's host range, temperature, pH, and chloroform stabilities. High-Resolution Transmission Electron Microscopy (HRTEM) was performed to determine the phage type.
RESULTS: Thirty HWW samples were analyzed using four K. pneumoniae AmpC strains resulting in a total of 120 screening plates. The AmpC-Klebsiella pneumoniae (AmpC-KP) phages were detected in 31.70% (38/120) of the plates. The AmpC-KP phages had lytic diameters ranging from 1-3 mm, and a phage titer ranged from4×103-3.2×107 PFU/ml. The phages had a narrow-host range stable at a temperature range from -20-50˚C. The phages were also stable at pH ranging from 4 to 9 and at different concentrations of chloroform (5%,10%). Based on HRTEM, Siphoviridea was identified.
CONCLUSIONS: The AmpC-phages were abundant in hospital wastewater, and HWW was a good source for AmpC-KP phages. The isolated AmpC phages had a high effectivity and specificity for AmpC-KP with a narrow host range and could survive under harsh conditions such as (temperature, pH, and chloroform).

Matched MeSH terms: Host Specificity
Fulltext Introducing a global database of entomopathogenic fungi and their host associations

De Wint FC, Nicholson S, Koid QQ, Zahra S, Chestney-Claassen G, Seelan JSS, et al.

Sci Data, 2024 Dec 21;11(1):1418.
PMID: 39709508 DOI: 10.1038/s41597-024-04103-4

Pathogens significantly influence natural and agricultural ecosystems, playing a crucial role in the regulation of species populations and maintaining biodiversity. Entomopathogenic fungi (EF), particularly within the Hypocreales order, exemplify understudied pathogens that infect insects and other arthropods globally. Despite their ecological importance, comprehensive data on EF host specificity and geographical distribution are lacking. To address this, we present EntomoFun 1.0, an open-access database centralizing global records of EF-insect associations in Hypocreales. This database includes 1,791 records detailing EF species, insect host taxa, countries of occurrence, life stages of hosts, and information sources. EntomoFun 1.0 is constructed based on 600 literature sources, as well as herbarium specimens of the Royal Botanical Gardens, Kew. This database is intended to test hypotheses, identify knowledge gaps, and stimulate future research. Contents of the EntomoFun 1.0 database are visualized with a global map, taxonomic chart, bipartite community network, and graphs.

Matched MeSH terms: Host Specificity
Fulltext The distribution and host range of the banana Fusarium wilt fungus, Fusarium oxysporum f. sp. cubense, in Asia

Mostert D, Molina AB, Daniells J, Fourie G, Hermanto C, Chao CP, et al.

PLoS One, 2017;12(7):e0181630.
PMID: 28719631 DOI: 10.1371/journal.pone.0181630

Fusarium oxysporum formae specialis cubense (Foc) is a soil-borne fungus that causes Fusarium wilt, which is considered to be the most destructive disease of bananas. The fungus is believed to have evolved with its host in the Indo-Malayan region, and from there it was spread to other banana-growing areas with infected planting material. The diversity and distribution of Foc in Asia was investigated. A total of 594 F. oxysporum isolates collected in ten Asian countries were identified by vegetative compatibility groups (VCGs) analysis. To simplify the identification process, the isolates were first divided into DNA lineages using PCR-RFLP analysis. Six lineages and 14 VCGs, representing three Foc races, were identified in this study. The VCG complex 0124/5 was most common in the Indian subcontinent, Vietnam and Cambodia; whereas the VCG complex 01213/16 dominated in the rest of Asia. Sixty-nine F. oxysporum isolates in this study did not match any of the known VCG tester strains. In this study, Foc VCG diversity in Bangladesh, Cambodia and Sri Lanka was determined for the first time and VCGs 01221 and 01222 were first reported from Cambodia and Vietnam. New associations of Foc VCGs and banana cultivars were recorded in all the countries where the fungus was collected. Information obtained in this study could help Asian countries to develop and implement regulatory measures to prevent the incursion of Foc into areas where it does not yet occur. It could also facilitate the deployment of disease resistant banana varieties in infested areas.

Matched MeSH terms: Host Specificity*
Fulltext Multiclonal human origin and global expansion of an endemic bacterial pathogen of livestock

Yebra G, Harling-Lee JD, Lycett S, Aarestrup FM, Larsen G, Cavaco LM, et al.

Proc Natl Acad Sci U S A, 2022 Dec 13;119(50):e2211217119.
PMID: 36469788 DOI: 10.1073/pnas.2211217119

Most new pathogens of humans and animals arise via switching events from distinct host species. However, our understanding of the evolutionary and ecological drivers of successful host adaptation, expansion, and dissemination are limited. Staphylococcus aureus is a major bacterial pathogen of humans and a leading cause of mastitis in dairy cows worldwide. Here we trace the evolutionary history of bovine S. aureus using a global dataset of 10,254 S. aureus genomes including 1,896 bovine isolates from 32 countries in 6 continents. We identified 7 major contemporary endemic clones of S. aureus causing bovine mastitis around the world and traced them back to 4 independent host-jump events from humans that occurred up to 2,500 y ago. Individual clones emerged and underwent clonal expansion from the mid-19th to late 20th century coinciding with the commercialization and industrialization of dairy farming, and older lineages have become globally distributed via established cattle trade links. Importantly, we identified lineage-dependent differences in the frequency of host transmission events between humans and cows in both directions revealing high risk clones threatening veterinary and human health. Finally, pangenome network analysis revealed that some bovine S. aureus lineages contained distinct sets of bovine-associated genes, consistent with multiple trajectories to host adaptation via gene acquisition. Taken together, we have dissected the evolutionary history of a major endemic pathogen of livestock providing a comprehensive temporal, geographic, and gene-level perspective of its remarkable success.

Matched MeSH terms: Host Specificity
An annotated checklist of sucking lice (Phthiraptera: Anoplura) from domestic and wild mammals in Malaysia, with lists of hosts and pathogens

Kazim AR, Houssaini J, Tappe D, Heo CC

Zootaxa, 2022 Dec 02;5214(3):301-336.
PMID: 37044900 DOI: 10.11646/zootaxa.5214.3.1

Literature records of sucking lice (Phthiraptera: Anoplura) from Malaysia were checked and reviewed, resulting in a list of 34 established species belonging to 11 genera (Ancistroplax, Atopophthirus, Enderleinellus, Haematopinus, Hamophthirius, Hoplopleura, Linognathus, Neohaematopinus, Pedicinus, Polyplax and Sathrax). Furthermore, three local and six cosmopolitan louse species are regarded as dubious in Malaysia, due to misidentifications or lack of locality records. Also, pathogens known to be associated with the sucking lice are listed. The alarming conservation status of some Malaysian mammalian host species and their sucking lice warrant more research and imminent action to preserve the biodiversity of the country. This paper presents the first complete checklist of anopluran lice from both Peninsular Malaysia and Malaysian Borneo, including localities, literature references and a host-louse list.

Matched MeSH terms: Host Specificity
Fulltext Chemotaxis movement and attachment of Agrobacterium tumefaciens to Phalaenopsis violacea orchid tissues: an assessment of early factors influencing the efficiency of gene transfer

Subramaniam, Sreeramanan, Balasubramaniam, Vinod, Poobathy, Ranjetta, Sreenivasan, Sasidharan, Rathinam, Xavier

Trop Life Sci Res, 2009;20(1):-.
MyJurnal

An early step in the Agrobacterium-mediated transformation of Phalaenopsis violacea orchid was investigated to elucidate the plant-bacterium interaction. Directed movement in response to chemical attractants is of crucial importance to Agrobacterium tumefaciens strains. Chemotaxis of A. tumefaciens strains (EHA 101 and 105) towards wounded orchid tissues has been studied by using swarm agar plates. The results obtained indicate a minor role for chemotaxis in determining host specificity and suggest that it could not be responsible for the absence of tumourigenesis in P. violacea orchid under natural conditions. The spectrometric GUS and green fluorescent protein (GFP) assays provided information on the amount of inoculated A. tumefaciens that effectively bound to various orchid tissues. It can be concluded that, at least during the two early steps of interaction, A. tumefaciens appears to be compatible with P. violacea, indicating a potential basis for genetic transformation.

Matched MeSH terms: Host Specificity
Whipworms of south-east Asian rodents are distinct from Trichuris muris

Ribas A, Wells K, Morand S, Chaisiri K, Agatsuma T, Lakim MB, et al.

Parasitol Int, 2020 Aug;77:102128.
PMID: 32330535 DOI: 10.1016/j.parint.2020.102128

The whipworm Trichuris muris is known to be associated with various rodent species in the northern hemisphere, but the species identity of whipworm infecting rodents in the Oriental region remains largely unknown. We collected Trichuris of Muridae rodents in mainland and insular Southeast Asia between 2008 and 2015 and used molecular and morphological approaches to identify the systematic position of new specimens. We discovered two new species that were clearly distinct from T. muris, both in terms of molecular phylogenetic clustering and morphological features, with one species found in Thailand and another one in Borneo. We named the new species from Thailand as Trichuris cossoni and the species from Borneo as Trichuris arrizabalagai. Molecular phylogeny using internal transcribed spacer region (ITS1-5.8S-ITS2) showed a divergence between T. arrizabalagai n. sp., T. cossoni n. sp. and T. muris. Our findings of phylogeographically distinct Trichuris species despite some globally distributed host species requires further research into the distribution of different species, previously assumed to belong to T. muris, which has particular relevance for using these species as laboratory model organisms.

Matched MeSH terms: Host Specificity
Characterization of the host specificity of the SH3 cell wall binding domain of the staphylococcal phage 88 endolysin

Tham HY, Chong LC, Krishnan M, Khan AM, Choi SB, Tamura T, et al.

Arch Microbiol, 2025 Jan 29;207(2):47.
PMID: 39878790 DOI: 10.1007/s00203-025-04242-1

Bacteriophages produce endolysins at the end of the lytic cycle, which are crucial for lysing the host cells and releasing virion progeny. This lytic feature allows endolysins to act as effective antimicrobial alternatives when applied exogenously. Staphylococcal endolysins typically possess a modular structure with one or two enzymatically active N-terminal domains (EADs) and a C-terminal cell wall binding domain (CBD). The EADs degrade the peptidoglycan layer, leading to bacterial lysis, while the CBD binds to the specific host cell wall, and therefore, influences specificity of the endolysin. This study aimed to alter and characterize the host specificity of the CBD by exploring the impact of amino acid modifications within the CBD of a staphylococcal endolysin, Endo88. Endo88 was able to lyse Staphylococcus spp. and Enterococcus faecalis. However, despite attempts to mutate amino acids hypothesized for binding with cell wall components, the host-range was not affected but the lytic activity was severely reduced instead, although no alterations were performed on the EADs (Cysteine, histidine-dependent aminohydrolases/peptidases domain and Amidase domain). Further investigations of the CBD alone (Src homology3 domain, SH3) without the EADs suggested that binding and lytic activity may not be correlated in some cases since Endo88 and its mutants could lyse Staphylococcus epidermidis well but no binding activity was observed in the flow cytometry analysis. Molecular docking was used to gain insights on the observations for the binding and lytic activity which may help future strategies in designing enhanced engineered endolysins.

Matched MeSH terms: Host Specificity*
Fulltext Genetic Diversity and Differentiation of Colletotrichum spp. Isolates Associated with Leguminosae Using Multigene Loci, RAPD and ISSR

Mahmodi F, Kadir JB, Puteh A, Pourdad SS, Nasehi A, Soleimani N

Plant Pathol J, 2014 Mar;30(1):10-24.
PMID: 25288981 DOI: 10.5423/PPJ.OA.05.2013.0054

Genetic diversity and differentiation of 50 Colletotrichum spp. isolates from legume crops studied through multigene loci, RAPD and ISSR analysis. DNA sequence comparisons by six genes (ITS, ACT, Tub2, CHS-1, GAPDH, and HIS3) verified species identity of C. truncatum, C. dematium and C. gloeosporiodes and identity C. capsici as a synonym of C. truncatum. Based on the matrix distance analysis of multigene sequences, the Colletotrichum species showed diverse degrees of intera and interspecific divergence (0.0 to 1.4%) and (15.5-19.9), respectively. A multilocus molecular phylogenetic analysis clustered Colletotrichum spp. isolates into 3 well-defined clades, representing three distinct species; C. truncatum, C. dematium and C. gloeosporioides. The ISSR and RAPD and cluster analysis exhibited a high degree of variability among different isolates and permitted the grouping of isolates of Colletotrichum spp. into three distinct clusters. Distinct populations of Colletotrichum spp. isolates were genetically in accordance with host specificity and inconsistent with geographical origins. The large population of C. truncatum showed greater amounts of genetic diversity than smaller populations of C. dematium and C. gloeosporioides species. Results of ISSR and RAPD markers were congruent, but the effective maker ratio and the number of private alleles were greater in ISSR markers.

Matched MeSH terms: Host Specificity
Fulltext Are bovine and porcine adenoviruses distinctive from other adenovirus strains?

Florence C. H. Lee, Lu Ping Tan

Malaysian Journal of Medicine and Health Sciences, 2019;15(106):86-86.
MyJurnal

Introduction: Adenoviruses are important in public health. They are used as indicators for microbial pollution source tracking (MST), and as vaccine vectors. Knowledge of host specificity and pre-existing immunity are critical for the two applications. Bovine and porcine adenoviruses are expected to be widespread in the environment through agriculture. Here we examined if bovine and porcine adenovirus strains are truly distinctive from other adenovirus strains. Methods: 46 adenovirus strains with complete genome were downloaded from the RefSeq database of Gen-Bank. 450 bp of nucleotides each at positions 1- 450, 18001-18450, and 27001 – 27450 of the respective strains were subjected to the Disparity Index Test using Mega 7 software. Analysis focused on four adenovirus strains: Bo-vine B, Bovine D, Porcine C and Porcine 3. The total number of strains that were significantly different (P

Matched MeSH terms: Host Specificity
Fulltext First molecular investigation of haemosporidian parasites in Thai bat species

Arnuphapprasert A, Riana E, Ngamprasertwong T, Wangthongchaicharoen M, Soisook P, Thanee S, et al.

Int J Parasitol Parasites Wildl, 2020 Dec;13:51-61.
PMID: 32904325 DOI: 10.1016/j.ijppaw.2020.07.010

Malaria parasites in the phylum Apicomplexa (Order: Haemosporida) infect diverse vertebrates and invertebrate hosts. At least seven genera of haemosporidian parasites have been described to exclusively infect bats. Most of these parasites remain enigmatic with a poorly known host range. Here, we investigated 271 bats belonging to 21 species and seven families from six provinces of Thailand. Overall, 124 out of 271 bats (45.8%) were positive for haemosporidian parasites, while none had Plasmodium, based on microscopic examination of blood smears and PCR amplification. We obtained 19 distinct cytochrome b (cytb) nucleotide haplotypes of Hepatocystis from seven bat species (families: Craseonycteridae, Hipposideridae, Pteropodidae, and Rhinolophidae). Nycteria was found in four bat species (Craseonycteridae, Emballonuridae, Megadermatidae, and Pteropodidae) and Polychromophilus in two species (Emballonuridae, Vespertilionidae). Phylogenetic analysis inferred from cytb sequences placed Hepatocystis into 2 different clades. Most Hepatocystis infections were found in insectivorous bats and clustered together with a sequence from Hipposideros larvatus in Cambodia (in subclade 1a). A single sequence of Hepatocystis obtained from a frugivorous bat, Cynopterus brachyotis, was placed in the same clade with Hepatocystis from the same bat species previously reported in Malaysia (clade 2). Nycteria in these Thai bats were clearly separated from the African isolates previously reported in bats in the family Rhinolophidae. Polychromophilus murinus from Myotis siligorensis was placed in a distinct clade (clade 2) from Polychromophilus melanipherus isolated from Taphozous melanopogon (clade 1). These results confirmed that at least two distinct species of Polychromophilus are found in Thailand. Collectively, Hepatocystis presented no host specificity. Although Megaderma spasma seemed to be infected by only Nycteria, its respective parasite does not show specificity to only a single bat host. Polychromophilus murinus and P. melanipherus seem to infect a narrower host range or are somehow restricted to bats in the families Vespertilionidae and Emballonuridae, respectively.

Matched MeSH terms: Host Specificity
Fulltext Isolation and Characterization of Six Vibrio parahaemolyticus Lytic Bacteriophages From Seafood Samples

Tan CW, Rukayadi Y, Hasan H, Abdul-Mutalib NA, Jambari NN, Hara H, et al.

Front Microbiol, 2021;12:616548.
PMID: 33776954 DOI: 10.3389/fmicb.2021.616548

Vibrio parahaemolyticus is a foodborne pathogen that is frequently isolated from a variety of seafood. To control this pathogenic Vibrio spp., the implementation of bacteriophages in aquaculture and food industries have shown a promising alternative to antibiotics. In this study, six bacteriophages isolated from the seafood samples demonstrated a narrow host range specificity that infecting only the V. parahaemolyticus strains. Morphological analysis revealed that bacteriophages Vp33, Vp22, Vp21, and Vp02 belong to the Podoviridae family, while bacteriophages Vp08 and Vp11 were categorized into the Siphoviridae family. All bacteriophages were composed of DNA genome and showed distinctive restriction fragment length polymorphism. The optimal MOI for bacteriophage propagation was determined to be 0.001 to 1. One-step growth curve revealed that the latent period ranged from 10 to 20 min, and the burst size of bacteriophage was approximately 17 to 51 PFU/cell. The influence of temperature and pH levels on the stability of bacteriophages showed that all bacteriophages were optimally stable over a wide range of temperatures and pH levels. In vitro lytic activity of all bacteriophages demonstrated to have a significant effect against V. parahaemolyticus. Besides, the application of a bacteriophage cocktail instead of a single bacteriophage suspension was observed to have a better efficiency to control the growth of V. parahaemolyticus. Results from this study provided a basic understanding of the physiological and biological properties of the isolated bacteriophages before it can be readily used as a biocontrol agent against the growth of V. parahaemolyticus.

Matched MeSH terms: Host Specificity
Fulltext Diversity and host associations of Myrsidea chewing lice (Phthiraptera: Menoponidae) in the tropical rainforest of Malaysian Borneo

Madrid RS, Sychra O, Benedick S, Edwards DP, Efeykin BD, Fandrem M, et al.

Int J Parasitol Parasites Wildl, 2020 Dec;13:231-247.
PMID: 33294362 DOI: 10.1016/j.ijppaw.2020.10.011

The tropical rainforests of Sundaland are a global biodiversity hotspot increasingly threatened by human activities. While parasitic insects are an important component of the ecosystem, their diversity and parasite-host relations are poorly understood in the tropics. We investigated parasites of passerine birds, the chewing lice of the speciose genus MyrsideaWaterston, 1915 (Phthiraptera: Menoponidae) in a natural rainforest community of Malaysian Borneo. Based on morphology, we registered 10 species of lice from 14 bird species of six different host families. This indicated a high degree of host specificity and that the complexity of the system could be underestimated with the potential for cryptic lineages/species to be present. We tested the species boundaries by combining morphological, genetic and host speciation diversity. The phylogenetic relationships of lice were investigated by analyzing the partial mitochondrial cytochrome oxidase I (COI) and the nuclear elongation factor alpha (EF-1α) genes sequences of the species. This revealed a monophyletic group of Myrsidea lineages from seven hosts of the avian family Pycnonotidae, one host of Timaliidae and one host of Pellorneidae. However, species delimitation methods supported the species boundaries hypothesized by morphological studies and confirmed that four species of Myrsidea are not single host specific. Cophylogenetic analysis by both distance-based test ParaFit and event-based method Jane confirmed overall congruence between the phylogenies of Myrsidea and their hosts. In total we recorded three cospeciation events for 14 host-parasite associations. However only one host-parasite link (M. carmenae and their hosts Terpsiphone affinis and Hypothymis azurea) was significant after the multiple testing correction in ParaFit. Four new species are described: Myrsidea carmenaesp.n. ex Hypothymis azurea and Terpsiphone affinis, Myrsidea franciscaesp.n. ex Rhipidura javanica, Myrsidea ramonisp.n. ex Copsychus malabaricus stricklandii, and Myrsidea victoriaesp.n. ex. Turdinus sepiarius.

Matched MeSH terms: Host Specificity
Leaf Spot on Lettuce (Lactuca sativa) Caused by Stemphylium solani, a New Disease in Malaysia

Nasehi A, Kadir JB, Esfahani MN, Mahmodi F, Ghadirian H, Ashtiani FA, et al.

Plant Dis, 2013 May;97(5):689.
PMID: 30722190 DOI: 10.1094/PDIS-10-12-0902-PDN

In June 2011, lettuce (Lactuca sativa) plants cultivated in major lettuce growing areas in Malaysia, including the Pahang and Johor states, had extensive leaf spots. In severe cases, disease incidence was recorded more than 80%. Symptoms on 50 observed plants initially were as water soaked spots (1 to 2 mm in diameter) on leaves, and then became circular spots spreading over much of the leaves. In this research, main lettuce growing areas infected by the pathogen in the mentioned states were investigated and the pathogen was isolated onto potato dextrose agar (PDA). Colonies observed were greyish green to light brown. Single conidia were formed at the terminal end of conidiophores that were 28.8 to 40.8 μm long and 11.0 to 19.2 μm wide, and 2 to 7 transverse and 1 to 4 longitudinal septa. To produce conidia, the fungus was grown on potato carrot agar (PCA) and V8 juice agar media under 8-h/16-h light/dark photoperiod. Fourteen isolates were identified Stemphylium solani based on morphological criteria described by Kim et al. (1). To confirm morphological characterization, DNA of the fungus was extracted from mycelium and PCR was done using universal primers ITS5 (5'-GGAAGTAAAAGTCGTAACAAGG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3'), which amplified the internal transcribed spacer (ITS) region of rDNA (2). The sequencing result was subjected to BLAST analysis which was 99% identical to the other published sequences in the GenBank database (GenBank Accession Nos. AF203451 and HQ840713). The nucleotide sequence was deposited in GenBank under Accession No. JQ736022. Pathogenicity testing of representative isolate was done using 20 μl of conidial suspension with a concentration of 1 × 105/ml in droplets (three drops on each leaf) on four detached 45-day-old lettuce leaves cv. BBS012 (3). Fully expended leaves were placed on moist filter paper in petri dishes and were incubated in humid chambers at 25°C. The leaves inoculated with sterile water served as control. After 7 days, disease symptoms were observed, which were similar to those symptoms collected in infected fields and the fungus was reisolated and confirmed as S. solani based on morphological criteria (1) and molecular characterization (2). Control leaves remained healthy. Pathogenicity testing was completed twice. To our knowledge, this is the first report of S. solani on lettuce in Malaysia and it may become a serious problem because of its broad host range, variability in pathogenic isolates, and prolonged active phase of the disease cycle. Previous research has shown that S. solani is a causal agent of gray leaf spot on lettuce in China (4). References: (1) B. S. Kim et al. Plant Pathol. J. 20:85, 2004. (2) Y. R. Mehta et al. Current Microbiol. 44:323, 2002. (3) B. M. Pryor and T. J. Michailides. Phytopathology 92:406, 2002. (4) F. L. Tai. Sylloge Fungorum Sinicorum, Sci. Press, Acad. Sin., Peking, 1979.

Matched MeSH terms: Host Specificity
Isolation and characterization of lytic vibriophage against Vibrio cholerae O1 from environmental water samples in Kelantan, Malaysia

Al-Fendi A, Shueb RH, Ravichandran M, Yean CY

J Basic Microbiol, 2014 Oct;54(10):1036-43.
PMID: 24532381 DOI: 10.1002/jobm.201300458

Water samples from a variety of sources in Kelantan, Malaysia (lakes, ponds, rivers, ditches, fish farms, and sewage) were screened for the presence of bacteriophages infecting Vibrio cholerae. Ten strains of V. cholerae that appeared to be free of inducible prophages were used as the host strains. Eleven bacteriophage isolates were obtained by plaque assay, three of which were lytic and further characterized. The morphologies of the three lytic phages were similar with each having an icosahedral head (ca. 50-60 nm in diameter), a neck, and a sheathed tail (ca. 90-100 nm in length) characteristic of the family Myoviridae. The genomes of the lytic phages were indistinguishable in length (ca. 33.5 kb), nuclease sensitivity (digestible with DNase I, but not RNase A or S1 nuclease), and restriction enzyme sensitivity (identical banding patterns with HindIII, no digestion with seven other enzymes). Testing for infection against 46 strains of V. cholerae and 16 other species of enteric bacteria revealed that all three isolates had a narrow host range and were only capable of infecting V. cholerae O1 El Tor Inaba. The similar morphologies, indistinguishable genome characteristics, and identical host ranges of these lytic isolates suggests that they represent one phage, or several very closely related phages, present in different water sources. These isolates are good candidates for further bio-phage-control studies.

Matched MeSH terms: Host Specificity
Fulltext Avian polyomavirus: a recent update

Padzil, F., Mariatulqabtiah, A. R., Abu, J.

Jurnal Veterinar Malaysia, 2017;29(2):9-13.
MyJurnal

Avian polyomavirus disease is among the most common viral diseases of domesticated exotic birds as such in psittacine families. Caused by avian polyomavirus (APV) which possess a circular, double-stranded DNA which encodes for major structural virus protein 1 (VP1) and minor structural proteins VP2, VP3 and VP4, the disease is also known as Budgerigar fledgling disease polyomavirus (BFPyV), Papovavirus, and Psittacine polyomavirus. Infections from APV may lead to cutaneous haemorrhage, abdominal distension, feather abnormalities and even death. The APV virus has a broad avian host range and is known to cause acute chronic disease in several psittacine birds such as parrot, cockatoo, macaw, and budgerigar. The current status of APV epidemiology globally has not been fully recorded. Only the studies of the virus and disease caused within several countries are used as references, and few were done together with detection of beak and feather disease virus. Despite the common occurrence of APV among bird breeders in Malaysia, a very limited study has been done to evaluate the prevalence status of APV in Malaysia. In this review, we wish to disseminate knowledge, particularly to pet owners and bird breeders, on APV characterisations, its updated occurrence worldwide and prevention strategies. This information may be useful to trigger in depth study on the epidemiology of disease and better management practises among breeders.

Matched MeSH terms: Host Specificity

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