Browsing by Author "Sajnaga, Ewa"

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    Bacteria from the midgut of common cockchafer (Melolontha melolontha L.) larvae exhibiting antagonistic activity against bacterial symbionts of entomopathogenic nematodes: isolation and molecular identification
    (MDPI, 2020-01-16) Skowronek, Marcin; Sajnaga, Ewa; Pleszczyńska, Małgorzata; Kazimierczak, Waldemar; Lis, Magdalena; Wiater, Adrian
    The mechanisms of action of the complex including entomopathogenic nematodes of the genera Steinernema and Heterorhabditis and their mutualistic partners, i.e., bacteria Xenorhabdus and Photorhabdus, have been well explained, and the nematodes have been commercialized as biological control agents against many soil insect pests. However, little is known regarding the nature of the relationships between these bacteria and the gut microbiota of infected insects. In the present study, 900 bacterial isolates that were obtained from the midgut samples of Melolontha melolontha larvae were screened for their antagonistic activity against the selected species of the genera Xenorhabdus and Photorhabdus. Twelve strains exhibited significant antibacterial activity in the applied tests. They were identified based on 16S rRNA and rpoB, rpoD, or recA gene sequences as Pseudomonas chlororaphis, Citrobacter murliniae, Acinetobacter calcoaceticus, Chryseobacterium lathyri, Chryseobacterium sp., Serratia liquefaciens, and Serratia sp. The culture filtrate of the isolate P. chlororaphis MMC3 L3 04 exerted the strongest inhibitory effect on the tested bacteria. The results of the preliminary study that are presented here, which focused on interactions between the insect gut microbiota and mutualistic bacteria of entomopathogenic nematodes, show that bacteria inhabiting the gut of insects might play a key role in insect resistance to entomopathogenic nematode pressure.
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    Bradyrhizobia associated with Laburnum anagyroides, an exotic legume grown in Poland
    (Springer, 2020) Sajnaga, Ewa; Jach, Monika Elżbieta
    We isolated 18 rhizobial strains from root nodules of a leguminous shrub Laburnum anagyroides (common laburnum) grown in Southeast Poland as an exotic plant. With the use of BOX-PCR fingerprinting, the isolates were clustered into 2 main groups and one separate lineage, which was congruent with the ITS-RFLP results. The phylogenetic trees constructed based on 16S rRNA and combined atpD, dnaK, glnA, and recA gene sequence data separated the representative strains into three evolutionary lineages within the Bradyrhizobium jicamae supergroup, with Bradyrhizobium algeriense and Bradyrhizobium valentinum as the closest relatives. The nodA and nifH gene phylogenies proved that the L. anagyroides symbionts carry a symbiotic gene variant known as Clade IV, representing the symbiovar retamae. Phenotypic characteristics of the isolates and reference strains are also reported. Our study of the rhizobia nodulating L. anagyroides growing in Poland complements earlier few findings on the symbiotic associations of this Genisteae species.
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    Comparative nanopore sequencing-based evaluation of the midgut microbiota of the summer chafer (Amphimallon solstitiale L.) associated with possible resistance to entomopathogenic nematodes
    (MDPI, 2022-03-15) Sajnaga, Ewa; Skowronek, Marcin; Kalwasińska, Agnieszka; Kazimierczak, Waldemar; Lis, Magdalena; Jach, Monika Elżbieta; Wiater, Adrian
    Root-feeding Amphimallon solstitiale larvae and certain other scarab beetles are the main soil-dwelling pests found in Europe, while entomopathogenic nematodes (EPN) have been used as a biocontrol agent against these species. Our study provides the first detailed characterization of the bacterial community of the midgut in wild A. solstitiale larvae, based on the nanopore sequencing of the 16S rRNA gene. In the whole dataset, we detected 2586 different genera and 11,641 species, with only 83 diverse bacterial genera shared by all studied individuals, which may represent members of the core midgut microbiota of A. solstitiale larvae. Subsequently, we compared the midgut microbiota of EPN-resistant and T0 (prior to EPN exposure) individuals, hypothesizing that resistance to this parasitic infection may be linked to the altered gut community. Compared to the control, the resistant insect microbiota demonstrated lower Shannon and Evenness indices and significant differences in the community structure. Our studies confirmed that the gut microbiota alternation is associated with resistant insects; however, there are many processes involved that can affect the bacterial community. Further research on the role of gut microbiota in insect-parasitic nematode interaction may ultimately lead to the improvement of biological control strategies in insect pest management.
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    Evolution and taxonomy of nematode-associated entomopathogenic bacteria of the genera Xenorhabdus and Photorhabdus: an overview
    (Springer Nature, 2020-01-10) Sajnaga, Ewa; Kazimierczak, Waldemar
    Entomopathogenic bacteria from the genera Photorhabdus and Xenorhabdus are closely related Gram-negative bacilli from the family Enterobacteriaceae (γ-Proteobacteria). They establish obligate mutualistic associations with soil nematodes from the genera Steinernema and Heterorhabditis to facilitate insect pathogenesis. The research of these two bacterial genera is focused mainly on their unique interactions with two different animal hosts, i.e. nematodes and insects. So far, studies of the mutualistic bacteria of nematodes collected from around the world have contributed to an increase in the number of the described Xenorhabdus and Photorhabdus species. Recently, the classification system of entomopatogenic nematode microsymbionts has undergone profound revision and now 26 species of the genus Xenorhabdus and 19 species of the genus Photorhabdus have been identified. Despite their similar life style and close phylogenetic origin, Photorhabdus and Xenorhabdus bacterial species differ significantly in e.g. the nematode host range, symbiotic strategies for parasite success, and arrays of released antibiotics and insecticidal toxins. As the knowledge of the diversity of entomopathogenic nematode microsymbionts helps to enable the use thereof, assessment of the phylogenetic relationships of these astounding bacterial genera is now a major challenge for researchers. The present article summarizes the main information on the taxonomy and evolutionary history of Xenorhabdus and Photorhabdus, entomopathogenic nematode symbionts.
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    Nanopore-sequencing characterization of the gut microbiota of Melolontha melolontha larvae: contribution to protection against entomopathogenic nematodes?
    (MDPI, 2021-03-25) Sajnaga, Ewa; Skowronek, Marcin; Kazimierczak, Waldemar; Ferenc, Karolina; Lis, Magdalena; Wiater, Adrian
    This study focused on the potential relationships between midgut microbiota of the common cockchafer Melolontha melolontha larvae and their resistance to entomopathogenic nematodes (EPN) infection. We investigated the bacterial community associated with control and unsusceptible EPN-exposed insects through nanopore sequencing of the 16S rRNA gene. Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes were the most abundant bacterial phyla within the complex and variable midgut microbiota of the wild M. melolontha larvae. The core microbiota was found to include 82 genera, which accounted for 3.4% of the total number of identified genera. The EPN-resistant larvae differed significantly from the control ones in the abundance of many genera belonging to the Actinomycetales, Rhizobiales, and Clostridiales orders. Additionally, the analysis of the microbiome networks revealed different sets of keystone midgut bacterial genera between these two groups of insects, indicating differences in the mutual interactions between bacteria. Finally, we detected Xenorhabdus and Photorhabdus as gut residents and various bacterial species exhibiting antagonistic activity against these entomopathogens. This study paves the way to further research aimed at unravelling the role of the host gut microbiota on the output of EPN infection, which may contribute to enhancement of the efficiency of nematodes used in eco-friendly pest management.
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    Production of enriched in B vitamins biomass of Yarrowia lipolytica grown in biofuel waste
    (Elsevier, King Saud University, 2021) Jach, Monika Elżbieta; Sajnaga, Ewa; Janeczko, Monika; Juda, Marek; Kochanowicz, Elżbieta; Baj, Tomasz; Malm, Anna
    Yarrowia lipolytica as an oleaginous yeast is capable of growing in various non-conventional hydrophobic substrate types, especially industrial wastes. In this study, the content of thiamine (vitamin B1), riboflavin (vitamin B2), pyridoxine (vitamin B6), biotin (vitamin B7) and folic acid (vitamin B9) in the wet biomass of Y. lipolytica strains cultivated in biofuel waste (SK medium), compared to the standard laboratory YPD medium, was assessed. Additionally, the biomass of Y. lipolytica A-101 grown in biofuel waste (SK medium) was dried and examined for B vitamins concentration according to the recommended microbial methods by AOAC Official Methods. The mean values of these vitamins per 100 g of dry weight of Y. lipolytica grown in biofuel waste (SK medium) were as follows: thiamine 1.3 mg/100 g, riboflavin 5.3 mg/100 g, pyridoxine 4.9 mg/100 g, biotin 20.0 µg/100 g, and folic acid 249 µg/100 g. We have demonstrated that the dried biomass is a good source of B vitamins which can be used as nutraceuticals to supplement human diet, especially for people at risk of B vitamin deficiencies in developed countries. Moreover, the biodegradation of biofuel waste by Y. lipolytica is desired for environmental protection.
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    Screening and molecular identification of bacteria from the midgut of Amphimallon solstitiale larvae exhibiting antagonistic activity against bacterial symbionts of entomopathogenic nematodes
    (MDPI, 2021-11-05) Skowronek, Marcin; Sajnaga, Ewa; Kazimierczak, Waldemar; Lis, Magdalena; Wiater, Adrian
    Entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) are a group of organisms capable of infecting larvae of insects living in soil, including representatives of the family Scarabaeidae. Their insecticidal activity is related to the presence of symbiotic bacteria Xenorhabdus spp. or Photorhabdus spp. in the alimentary tract, which are released into the insect body, leading to its death caused by bacterial toxins and septicemia. Although the antibacterial activities of symbionts of entomopathogenic nematodes have been well described, there is insufficient knowledge of the interactions between these bacteria and microorganisms that naturally inhabit the alimentary tract of insects infested by nematodes. In this study, 900 bacterial strains isolated from midgut samples of Amphimallon solstitiale larvae were tested for their antagonistic activity against the selected five Xenorhabdus and Photorhabdus species. Cross-streak tests showed significant antibacterial activity of 20 isolates. These bacteria were identified as Bacillus [Brevibacterium] frigoritolerans, Bacillus toyonensis, Bacillus wiedmannii, Chryseobacterium lathyri, Chryseobacterium sp., Citrobacter murliniae, Enterococcus malodoratus, Paenibacillus sp., Serratia marcescens and Serratia sp. Since some representatives of the intestinal microbiota of A. solstitiale are able to inhibit the growth of Xenorhabdus and Photorhrhabdus bacteria in vitro, it can be assumed that this type of bacterial interaction may occur at certain stages of insect infection by Steinernema or Heterorhabditis nematodes.
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    Steinernema poinari (Nematoda: Steinernematidae): a new symbiotic host of entomopathogenic bacteria Xenorhabdus bovienii
    (Springer, 2018-06-19) Sajnaga, Ewa; Kazimierczak, Waldemar; Skowronek, Marcin; Lis, Magdalena; Skrzypek, Tomasz; Waśko, Adam
    Three strains of symbiotic bacteria were isolated from an entomopathogenic nematode Steinernema poinari retrieved from soil in eastern Poland. Using 16S rDNA, recA, gltX, gyrB, and dnaN gene sequences for phylogenetic analysis, these strains were shown to belong to the species Xenorhabdus bovienii. The nucleotide identity between the studied S. poinari microsymbionts and other X. bovienii strains calculated for 16S rDNA and concatenated sequences of four protein-coding genes was 98.7–100% and 97.9–99.5%, respectively. The phenotypic properties of the isolates also supported their close phylogenetic relationship with X. bovienii. All three tested X. bovienii strains of diffrent Steinernema clade origin supported the recovery of infective juveniles and subsequent development of the nematode population. However, the colonization degree of new infective juvenile generations was signifiantly affcted by the bacterial host donor/recipient. The colonization degree of infective juveniles reared on bacterial symbionts deriving from a non-cognate clade of nematodes was extremely low, but proved the possible host-switching between non-related Steinernema species.
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    Steinernema sandneri n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from Poland
    (Exeley, 2021-05-21) Lis, Magdalena; Sajnaga, Ewa; Skowronek, Marcin; Wiater, Adrian; Rachwał, Kamila; Kazimierczak, Waldemar
    A new species of entomopathogenic nematodes, Steinernema sandneri n. sp., was recovered by baiting from Poland. Its morphological traits indicate that the new species is a member of the feltiae-kraussei group. A body length of 843 (708-965) μm., a more anterior position of excretory pore (56 μm), and the lower D% value (40 vs. >46) discriminate this species from most of the other group members. The first-generation males of S. sandneri n. sp. can be distinguished from the other clade members by a 60 μm long spicule, a relatively long gubernaculum (GS%=79), and the position of the excretory pore (80 μm). Phylogenetic analysis of the ITS rDNA, D2D3 of 28S rDNA, and cox1 sequences confirmed that S. sandneri n. sp. is a new species of the feltiae-kraussei group, closely related to S. kraussei and S. silvaticum.
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    Utilization of Legume-Nodule Bacterial Symbiosis in Phytoremediation of Heavy Metal-Contaminated Soils
    (MDPI, 2022) Jach, Monika Elżbieta; Sajnaga, Ewa; Ziaja, Maria
    With the increasing industrial activity of the growing human population, the accumulation of various contaminants in soil, including heavy metals, has increased rapidly. Heavy metals as non-biodegradable elements persist in the soil environment and may pollute crop plants, further accumulating in the human body causing serious conditions. Hence, phytoremediation of land contamination as an environmental restoration technology is desirable for both human health and broad-sense ecology. Legumes (Fabaceae), which play a special role in nitrogen cycling, are dominant plants in contaminated areas. Therefore, the use of legumes and associated nitrogen-fixing rhizobia to reduce the concentrations or toxic effects of contaminants in the soil is environmentally friendly and becomes a promising strategy for phytoremediation and phytostabilization. Rhizobia, which have such plant growth-promoting (PGP) features as phosphorus solubilization, phytohormone synthesis, siderophore release, production of beneficial compounds for plants, and most of all nitrogen fixation, may promote legume growth while diminishing metal toxicity. The aim of the present review is to provide a comprehensive description of the main effects of metal contaminants in nitrogen-fixing leguminous plants and the benefits of using the legume–rhizobium symbiosis with both wild-type and genetically modified plants and bacteria to enhance an efficient recovery of contaminated lands.
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    Vitamin B12-Enriched Yarrowia lipolytica Biomass Obtained from Biofuel Waste
    (Springer, 2020) Jach, Monika Elżbieta; Masłyk, Maciej; Juda, Marek; Sajnaga, Ewa; Malm, Anna
    The aim of the study was to obtain vitamin B12-enriched biomass of non-conventional yeast Yarrowia lipolytica A-101. The cultivations were performed on waste from biofuel production in aerobic conditions at different temperatures (20–30 °C) and pH values (4.0–7.0) of the medium, with and without the addition of cobalt, L-methionine, molybdenum, δ-aminolevulinic acid, and niacin. A temperature of 30 °C and pH between 5 and 6 were the optimal conditions for obtaining B12-enriched yeast biomass on biofuel waste. In such conditions, Y. lipolytica A-101 contained 9 µg of vitamin B12 per 100 g of dried biomass. The addition of the ingredients mentioned above to the medium did not exert a significant effect on the B12 concentration. Y. lipolytica are able to accumulate this vitamin from the medium in a similar manner to animal cells. Additionally, it should be noted that the dried biomass of Y. lipolytica appeared to be safe for consumption. Taken together, these data showed that Y. lipolytica can be used as a nutritional supplement to increase the intake of vitamin B12, especially at risk of vitamin B12 deficiency.