Pathogenic Species Research Articles

A comprehensive in silico analysis of putative outer membrane and secretory hydrolases from the pathogenic Leptospira: Possible implications in pathogenesis.

Outer surface/membrane and virulent secretory proteins are primarily crucial for pathogenesis. Secreted and outer membrane hydrolases of many pathogens play an important role in attenuating the host immune system. Leptospira expresses many such proteins, and few have been characterized to display various roles, including host immune evasion. However, identification, classification, characterization, and elucidation of the possible role of Leptospira's outer membrane and secretory hydrolases have yet to be explored. In the present study, we used bioinformatics tools to predict exported proteins from the pathogenic Leptospira proteome. Moreover, we focused on secretory and outer membrane putative hydrolases from the exported proteins to generate a deeper understanding. Our analysis yielded four putative outer/secretory hydrolases, LIC_10995, LIC_11183, LIC_11463, and LIC_12988, containing α/β hydrolase fold and displayed similarity with lipase motif. Moreover, their conservation analysis of the predicted hydrolases across the spectrum of different Leptospira species showed high clustering with the pathogenic species. Outer membrane and secretory proteins with lipolytic activity may have a role in pathogenesis. This is the first bioinformatics analysis of secretory and outer membrane α/β hydrolases from leptospiral species. However, experimental studies are indeed required to unravel this possibility.

Genotyping of Borrelia, Rickettsia and Anaplasma in Ixodes ricinus and Dermacentor reticulatus ticks in the Kaliningrad region

Background. Tick-borne bacterial and protozoal pathogens pose a significant public health problem. The aim of this study was to detect and genotype Borrelia, Rickettsia and Anaplasma in Ixodes ricinus and Dermacentor reticulatus ticks collected in the Kaliningrad region in 2021–2022. Materials and methods. The study included 862 I. ricinus and 803 D. reticulatus ticks (1665 in total) collected in 33 biotopes of the Kaliningrad region. Detection of the DNA of tick-borne pathogens was carried out in individual ticks by PCR using a set of specific primers, followed by sequencing and phylogenetic analysis. Results. The level of infection of I. ricinus ticks with Borrelia was 15.5%, and genotyping by the p66 gene sequence showed the presence of genetic material from four species: B. afzelii, B. garinii, B. valaisiana, and B. lusitaniae. In D. reticulatus ticks, no Borrelia genetic material was detected. The Rickettsia DNA has been found in both tick species. Moreover, the infection rate of I. ricinus ticks was 2.6%, and D. reticulatus — 21.2%. R. helvetica were found in I. ricinus ticks, and R. raoultii in meadow ticks when genotyping by gltA gene. Genetic markers of Anaplasma phagocytophilum have been found in I. ricinus and D. reticulatus ticks. Cases of co-infection of an individual tick have also been identified. Conclusion. Six different species of tick-borne pathogens were found in the I. ricinus and D. reticulatus ticks collected in the Kaliningrad region and R. helvetica, R. raoultii and A. phagocytophilum were identified for the first time.

Identification of equine mares as reservoir hosts for pathogenic species of Leptospira

Equine leptospirosis can result in abortion, stillbirth, neonatal death, placentitis, and uveitis. Horses can also act as subclinical reservoir hosts of infection, which are characterized as asymptomatic carriers that persistently excrete leptospires and transmit disease. In this study, PCR and culture were used to assess urinary shedding of pathogenic Leptospira from 37 asymptomatic mares. Three asymptomatic mares, designated as H2, H8, and H9, were PCR-positive for lipL32, a gene specific for pathogenic species of Leptospira. One asymptomatic mare, H9, was culture-positive, and the recovered isolate was classified as L. kirschneri serogroup Australis serovar Rushan. DNA capture and enrichment of Leptospira genomic DNA from PCR-positive, culture-negative samples determined that asymptomatic mare H8 was also shedding L. kirschneri serogroup Australis, whereas asymptomatic mare H2 was shedding L. interrogans serogroup Icterohaemorrhagiae. Sera from all asymptomatic mares were tested by the microscopic agglutination test (MAT) and 35 of 37 (94.6%) were seropositive with titers ranging from 1:100 to 1:3200. In contrast to asymptomatic mares, mare H44 presented with acute spontaneous abortion and a serum MAT titer of 1:102,400 to L. interrogans serogroup Pomona serovar Pomona. Comparison of L. kirschneri serogroup Australis strain H9 with that of L. interrogans serogroup Pomona strain H44 in the hamster model of leptospirosis corroborated differences in virulence of strains. Since lipopolysaccharide (LPS) is a protective antigen in bacterin vaccines, the LPS of strain H9 (associated with subclinical carriage) was compared with strain H44 (associated with spontaneous abortion). This revealed different LPS profiles and immunoreactivity with reference antisera. It is essential to know what species and serovars of Leptospira are circulating in equine populations to design efficacious vaccines and diagnostic tests. Our results demonstrate that horses in the US can act as reservoir hosts of leptospirosis and shed diverse pathogenic Leptospira species via urine. This report also details the detection of L. kirschneri serogroup Australis serovar Rushan, a species and serotype of Leptospira, not previously reported in the US.

In Saccharomyces cerevisiae ρ0 Cells, UME6 Contributes to the Activation of ABC Transporter Genes and Pleiotropic Drug Resistance via RPD3 and PDR3

In Saccharomyces cerevisiae, the Rpd3L complex includes the histone deacetylase Rpd3 and the DNA binding proteins Ume6 and Ash1 and serves as a transcriptional silencer or enhancer. In S. cerevisiae, the transcription of PDR5, which encodes a major drug efflux pump, and pleiotropic drug resistance (PDR) are hyperactivated by the transcription factor Pdr3 in ρ0/− cells, which lack mitochondrial DNA. We previously showed that RPD3 and UME6 are required for the activation of PDR5 transcription and PDR in S. cerevisiae ρ0 cells. Here, using real-time PCR analysis, we revealed that RPD3 and UME6 are responsible for the activated basal expression of the ABC transporter-encoding genes SNQ2, PDR15, and PDR5 in S. cerevisiae ρ0 cells. Furthermore, using real-time PCR analysis and a spot dilution assay, we found that Ume6 increases the basal expression of PDR5 and PDR15 and induces PDR in a manner dependent on RPD3 and PDR3 in ρ0 cells. This finding may contribute to the elucidation of the relationships between the molecules required for the activation of ABC transporter genes in S. cerevisiae ρ0/− cells and in pathogenic Candida species.

Ultrasonic Pretreatment Combined with Microwave-Assisted Hydrodistillation for Extraction of Essential Oil from Melaleuca bracteata ‘Revolution Gold’ Leaves Scales Induced by Cellulase-Inorganic Salt and Its Anti-Fungal Activity

In order to further develop the commercial use of Melaleuca bracteata (F. Muell), this report studied the extraction of essential oil from Melaleuca bracteata (F. Muell) leaves using ultrasonic pretreatment, cellulase-inorganic salt soaked and combined with microwave-assisted hydrodistillation. To optimize the primary contributing parameters, the Box–Behnken design (BBD) was applied. The optimum yield of essential oil was 9.61 mL/kg DW at a microwave power of 510.77 W, lithium chloride dose of 63.56 μmol, and microwave irradiation period of 46.97 min. The essential oil included a total of 41 compounds, and methyl eugenol (76.53%) and methyl cinnamate (12.62%) were the main compounds. The inhibitory impact was notable when the essential oil concentration was 1.6 mg/mL. Therefore, it has the potential to replace chemical pesticides. When the concentration of the essential oil solution was 1.6 mg/mL, the three pathogenic species of fungus (Pseudocercospora psidii, Colletotrichum eriobotryae, and Colletotrichum siamense) were greatly affected; at this dose, the fungus was unable to develop and its growth diameter was 0 mm. Additionally, the fungus’s inhibition rate reached 100%.

Description of a pathogenic strain of Aeromonas dhakensis isolated from Ancherythroculter nigrocauda in an inland region of China.

Aeromonas dhakensis is reported as an emerging pathogenic species within the genus Aeromonas and is widely distributed in tropical coastal areas. This study provided a detailed description and characterization of a strain of A. dhakensis (202108B1) isolated from diseased Ancherythroculter nigrocauda in an inland region of China. Biochemical tests identified the isolate at the genus level, and the further molecular analysis of concatenated housekeeping gene sequences revealed that the strain belonged to the species A. dhakensis. The isolated A. dhakensis strain was resistant to five antibiotics, namely, penicillin, ampicillin, clindamycin, cephalexin and imipenem, while it was susceptible or showed intermediate resistance to most of the other fifteen tested antibiotics. The isolated strain of A. dhakensis caused acute haemorrhagic septicaemia and tissue damage in artificially infected A. nigrocauda, with a median lethal dose of 7.76×104 CFU/fish. The genome size of strain 202108B1 was 5043286 bp, including one chromosome and four plasmids. This is the first detailed report of the occurrence of infection caused by an A. dhakensis strain causing infection in an aquaculture system in inland China, providing important epidemiological data on this potential pathogenic species.

Impact of leptospirosis on animal reproduction and its legal and forensic aspects in “One Health”

Requirements covering animal, public and environmental health challenge veterinary medicine and the law. In this context, legal and forensic veterinary medicine in Brazil has grown in recent years with significant scientific knowledge. Several animals are reservoirs and carriers of zoonoses which transmit pathogens to humans. Leptospirosis is an infectious disease that impacts animal reproduction and production with negative consequences on animal, public and environmental health (One Health). It is an important zoonosis caused by pathogenic species of the genus Leptospira spp. It is distributed worldwide and transmission to susceptible species occurs through direct or indirect contact with infected individuals. Poor sanitation and garbage collection favor the presence of substrates that attract rodents to properties, increasing the risk of the disease occurring. The World Health Organization (WHO) founded Veterinary Public Health, an area that includes the Veterinary Doctor with responsibilities in public health actions, with an important role in One Health. This literature review was designed based on current knowledge on the platforms Pubmed and Google Scholar, articles and textbooks. We aim to identify, understand and discuss the impacts of leptospirosis on reproduction, animal health, public health, and its legal and forensic aspects in One Health. The disease is an animal, public, and environmental health problem that has seasonal characteristics and occurs in urban and rural areas. It is a neglected disease and is directly related to precarious urban and health infrastructure. The veterinarian plays a fundamental role in assisting legal and forensic legal actions in the field of One Health.

Phytophthora and Phytopythium species associated with walnut dieback in plantations of northern Patagonia, Argentina

AbstractThe walnut industry in Argentina has grown in recent years, especially in northern Patagonia. However, this expansion has also brought new challenges, including the emergence of diseases threatening the health and productivity of walnut plantations. One of the most important diseases affecting walnut crops worldwide is ‘ink disease’ or ‘walnut dieback'. The aim of this study was to characterize ink disease, identify the aetiological agents, and estimate its incidence in walnut orchards of northern Patagonia, Argentina. Symptomatic trees were observed in the seven surveyed walnut orchards, showing a range of symptoms, including chlorosis and wilting, stem cankers and desiccation. In vivo assay and molecular analyses revealed that not only Phytophthora (P.) but also Phytopythium (Ph.) species are the causal agents of the disease, with P. drechsleri, Ph. mercuriale and Ph. vexans  being the most virulent over the commonly used rootstock Juglans hindsii. Notably, Ph. vexans was the most frequently isolated pathogen, suggesting its prevalence and potential impact on the regional walnut industry. Overall, this study provides critical insights into the prevalence and impact of Phytophthora and Phytopythium species on walnut health in northern Patagonia. The presence of multiple pathogenic oomycete species raises concerns about the health of walnut orchards, as well as the potential risk of pathogen transmission to other fruit crops in the region. The findings will help growers to develop better cultural practices and implement measures to guarantee the sustainability of the walnut industry in Patagonia.

Multi-omics reveal the gut microbiota-mediated severe foraging environment adaption of small wild ruminants in the Three-River-Source National Park, China.

The Tibetan antelope (Pantholops hodgsonii), blue sheep (Pseudois nayaur), and Tibetan sheep (Ovis aries) are the dominant small ruminants in the Three-River-Source National Park (TRSNP). However, knowledge about the association between gut microbiota and host adaptability remains poorly understood. Herein, multi-omics sequencing approaches were employed to investigate the gut microbiota-mediated forage adaption in these ruminants. The results revealed that although wild ruminants (WR) of P. hodgsoni and P. nayaur were faced with severe foraging environments with significantly low vegetation coverage and nutrition, the apparent forage digestibility of dry matter, crude protein, and acid detergent fiber was significantly higher than that of O. aries. The 16s rRNA sequencing showed that the gut microbiota in WR underwent convergent evolution, and alpha diversity in these two groups was significantly higher than that in O. aries. Moreover, indicator species, including Bacteroidetes and Firmicutes, exhibited positive relationships with apparent forage digestibility, and their relative abundances were enriched in the gut of WR. Enterotype analysis further revealed that enterotype 1 belonged to WR, and the abundance of fatty acid synthesis metabolic pathway-related enzyme genes was significantly higher than enterotype 2, represented by O. aries. Besides, the metagenomic analysis identified 14 pathogenic bacterial species, among which 10 potentially pathogenic bacteria were significantly enriched in the gut microbiota of O. aries. Furthermore, the cellulolytic strains and genes encoding cellulase and hemicellulase were significantly enriched in WR. In conclusion, our results provide new evidence of gut microbiota to facilitate wildlife adaption in severe foraging environments of the TRSNP, China.

Development of a prototypic, field-usable diagnostic tool for the detection of gram-positive cocci-induced mastitis in cattle

BackgroundBovine mastitis is one of the most widespread diseases affecting cattle, leading to significant losses for the dairy industry. Currently, the so-called gold standard in mastitis diagnosis involves determining the somatic cell count (SCC). Apart from a number of advantages, this method has one serious flaw: It does not identify the etiological factor causing a particular infection, making it impossible to introduce targeted antimicrobial therapy. This can contribute to multidrug-resistance in bacterial species. The diagnostic market lacks a test that has the advantages of SCC and also recognizes the species of pathogen causing the inflammation. Therefore, the aim of our study was to develop a lateral flow immunoassay (LFIA) based on elongation factor Tu for identifying most prevalent Gram-positive cocci responsible for causing mastitis including Streptococcus uberis, Streptococcus agalactiae and Staphylococcus aureus.ResultsAs a result, we showed that the assay for S. uberis detection demonstrated a specificity of 89.02%, a sensitivity of 43.59%, and an accuracy of 80.3%. In turn, the second variant - assay for Gram-positive cocci reached a specificity of 95.59%, a sensitivity of 43.28%, and an accuracy of 78.33%.ConclusionsOur study shows that EF-Tu is a promising target for LFIA and we have delivered evidence that further evaluation could improve test parameters and fill the gap in the mastitis diagnostics market.

Modelling the Dynamics of Microbial Population and Salmonella spp. in Milk Kefir

Kefir is a fermented dairy product based on the fermentation of milk by bacteria and yeasts. It is produced by adding kefir grains, consisting of a consortium of microorganisms, to milk in order to start a natural fermentation (Garofalo et al., 2020). Kefir is well recognized for its potential health value as a source of probiotics, however, there have been concerns about the potential growth of pathogenic microorganisms in kefir and the potential health hazards associated (Leite et al., 2013)A mathematical model was developed to describe the evolution of microbes present during kefir fermentation and the potential growth of Salmonella spp. as one example of a potential food safety hazard. For this, equations previously described in the scientific literature were combined and adapted to the milk kefir matrix. To assess the safety of the product, the growth of Salmonella was predicted considering its interaction with the medium and the other species. The drop in pH; generation of yeasts metabolites such as ethanol; and buffer capacity was described and considered when modelling Salmonellas’ kinetics. Interaction between the pathogenic species and the background microflora was included in the model.Parameters of some well-described systems were taken from literature. Alongside, some other parameters describing specific assets from the system were estimated using experimental data of microbial population kinetics during kefir fermentation. The growth of yeasts, lactic acid bacteria, Salmonella together with the pH were experimentally collected at critical processing times and fitted to the mathematical model by minimizing the residual sum of squares (RSS). Confidence intervals of 95% were calculated. For further validation, the output of the model was contrasted with an independent data set.It was concluded that Salmonella is able to increase its population during the first hours of the kefir fermentation process. Inactivation can be apportioned to the drop of pH as a consequence of the LAB metabolism, once the pH reaches values below 4. After this no growth of Salmonella seems to be found in milk kefir as confirmed by the model. No residual population of the pathogen is observed. This suggests that by controlling the growth and metabolism of the background microflora, safety can be assured in milk kefir. This process was successfully described by a novel mathematical model and the estimation of its´parameters.

Antibiofilm effect of rubrolide analogues and derived lactams on single-species biofilms

In this study, a series of 26 lactones and lactams have been investigated for their effect against 14 single-species biofilm of oral commensal and pathogenic species (Streptococcus oralis, S. mitis, S. sanguinis, S. gordonii, Actinomyces naeslundii, A. viscosus, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Streptococcus mutans, S. sobrinus, S. salivarius, Veillonella parvula). At the dose of 128 mg/mL, all substances inhibited biofilm formation of S. oralis by more than 60%, and 19 caused >60% reduction in the biofilm production by S. sanguinis and A. naeslundi. In addition, 16 compounds showed better results against P. intermedia and F. nucleatum, inhibiting biofilm formation by > 50%, while 8 compounds caused >40% reduction in the biofilm formation of A. actinomycetemcomitans. Compounds 5b, 5c, 5d, 5f, and 7g were the only ones active against S. mutans, and 6d was the only one active against S. sobrinus biofilm formation. Amongst all compounds tested, 24 maintained cell viability above 50% after 24 h of exposure. In summary, a set of lactones and lactams capable of inhibiting single-species biofilms of oral commensal and pathogenic bacteria without showing significant cytotoxicity against oral epithelial cells were identified. These results highlight the potential of using such antibiofilm compounds as an alternative approach to control oral biofilms.

Pathogens of the oak processionary moth Thaumetopoea processionea: Developing a user-friendly bioassay system and metagenome analyses for microorganisms.

The oak processionary moth (OPM) Thaumetopoea processionea is a pest of oak trees and poses health risks to humans due to the urticating setae of later instar larvae. For this reason, it is difficult to rear OPM under laboratory conditions, carry out bioassays or examine larvae for pathogens. Biological control targets the early larval instars and is based primarily on commercial preparations of Bacillus thuringiensis ssp. kurstaki (Btk). To test the entomopathogenic potential of other spore-forming bacteria, a user-friendly bioassay system was developed that (i) applies bacterial spore suspensions by oak bud dipping, (ii) targets first larval instar larvae through feeding exposure and (iii) takes into account their group-feeding behavior. A negligible mortality in the untreated control proved the functionality of the newly established bioassay system. Whereas the commercial Btk HD-1 strain was used as a bioassay standard and confirmed as being highly efficient, a B. wiedmannii strain was ineffective in killing OPM larvae. Larvae, which died during the infection experiment, were further subjected to Nanopore sequencing for a metagenomic approach for entomopathogen detection. It further corroborated that B.wiedmannii was not able to infect and establish in OPM, but identified potential insect pathogenic species from the genera Serratia and Pseudomonas.

Bacterial community of ticks (Acari: Ixodidae) and mammals from Arauca, Colombian Orinoquia

Ticks are obligate hematophagous ectoparasites of vertebrates and are relevant worldwide due to the number of bacterial and other pathogens they can transmit. To date, the knowledge about the microorganisms that ticks harbor and transmit to their hosts is incipient. In this study, 24 samples of mammals belonging to four taxonomic orders and ticks of the genera Amblyomma and Rhipicephalus from the Orinoco region of Colombia were analyzed to described and compare the bacterial microbiome. Genetic extraction was performed, and the V3-V4 region of the 16S rRNA gene was amplified by PCR. Libraries were created, and those samples with adequate quality indices were sequenced using Illumina MiSeq technology. Bacterial taxonomic assignment analyses were conducted through Amplicon Sequence Variants (ASVs) and Operational Taxonomic Units (OTUs). The results correspond to 16 samples that passed the quality filters, with 3,218 OTUs (415 families). Although a considerable number of unknown bacteria was found, Enterobacteriaceae, Beijerinckiaceae, Moraxellaceae, and Burkholderiaceae are the most prevalent families, and the presence of the genera Coxiella, Escherichia-Shigella, Enterobacter, which can harbor pathogenic species was confirmed. In individuals of Amblyomma mixtum found actively feeding on Hydrochoerus hydrochaeris, and bacteria of the genera Escherichia-Shigella and Enterobacter were documented. Similarly, Rhipicephalus microplus found actively feeding on Odocoileus virginianus cariacou shared Escherichia-Shigella. Ralstonia was shared among the blood samples of H. hydrochaeris, while Anaplasma and Eubacterium were shared in blood and liver samples of O. v. cariacou. Shared bacteria between A. mixtum and R. microplus included Bacillus, Coxiella, and Escherichia-Shigella. The results highlight the need of additional studies in other natural regions of Colombia and other American countries where tick-borne diseases have been detected. Likewise, the recorded data are the first at the level of bacterial communities in ticks of the family Ixodidae and provide valuable knowledge for the understanding host-tick and pathogen interactions.

Effects of molasses-based microbial dust suppressant on soil dust and microbial community

This study aims at the practical needs of soil dust control and molasses resource utilization. By adding molasses to the soil and combining it with the components of microbial dust suppressants, it explores its impact on the surface soil dust suppression performance and microbial communities. The results show that after spraying treatment, the soil surface hardness is positively correlated with the molasses concentration, the surface hardness is the highest (41.14 HA) when the molasses concentration is 10%; the anti-wind erosion effect shows a trend of first increasing and then decreasing with the molasses concentration, the anti-rain erosion effect needs to be improved; microbial community analysis show that molasses significantly affected the relative abundance of soil microbial community, and appropriate addition (1%) could optimize the microbial community structure and enhance the functions of carbohydrate and energy metabolism pathways, and the abundance of pathogenic species increased when the molasses concentration was higher (above 5%). Therefore, considering the dust suppression effect and environmental safety, a dust suppressant with a molasses concentration of 1% is more suitable for dust suppression. However, the synergistic pathway and mechanism of dust suppression through the interaction between molasses and MICP technology need to be further explored.

First Report of Fusarium pernambucanum Causing Fruit Rot of Melon in China.

In May of 2020, November of 2021 and May of 2022, a preharvest fruit rot with white mycelia was observed inside and outside of the fruits of thick skin muskmelon (Cucumis melo L.) growing in about ten greenhouses (each greenhouse had about 320 muskmelons) with disease incidence of 70% in Ningbo, Zhejiang Province of China. In order to identify the causal agent, plant tissues from the margin of the symptomatic tissue were sterilized for 1 min with 1% sodium hypochlorite (NaClO), 2 min with 75% ethyl alcohol, rinsed in sterile distilled water three times (Zhou et al 2019), and then placed on potato dextrose agar (PDA) plates containing streptomycin sulfate (100 μg/mL) at 25℃ for 4 days. Only Fusarium colonies were isolated from all the plant tissues. The growing hyphae were transferred to new PDA plates using the hyphal tip method, putative Fusarium colonies were purified by single-sporing. Six fungal isolates (Fi-1~6) were obtained. The average radial mycelial growth rate of Fusarium isolate Fi-3 was 4.6 mm/day at 25℃ in the dark on PDA, and like other five isolates. The colonies are abnormal, producing lots of aerial hyphae, each isolate was white to light orange. Isolate Fi-3 produced macroconidia with 4 to 6 septa, tapered with pronounced dorsiventral curvature and measured 21 to 30 μm long 4 to 5 μm wide on Spezieller Nährstoffarmer Agar (SNA) medium at 25℃ for 10 days (Leslie and Summerell 2006), but polyphialides and chlamydospores were still not available for 30 days. The pathogen species was further identified by translation elongation factor-1 alpha (EF-1α) sequencing. The EF-1α of six isolates were sequenced, and their EF-1α sequences were 100% identical to each other, and the sequence of strain Fi-3 was deposited in GenBank with accession no. OL782040 and was also compared with sequences in the FUSARIUM-ID database (Geiser et al. 2004), which indicated that it was 100% identical to those of F. pernambucanum strain NRRL 32864 (GenBank accession GQ505613), F. pernambucanum strain LC7040 (GenBank accession MK289626), and F. pernambucanum strain LC12149 (GenBank accession MK289588) within the Fusarium incarnatum - F. equiseti species complex 17 (FIESC17). Two phylogenetic trees were established based on the TEF1-α sequences of Fi-1~6 and other Fusarium spp., Fi-1~6 was clustered with the sequences of F. pernambucanum within the FIESC17. Thus, both morphological and molecular criteria supported identification of the strain as F. pernambucanum. A pathogenicity test was conducted to verify Koch's postulates, mycelium agar plugs (6 mm in diameter) were removed from the colony margin of a 3-day-old culture of strain Fi-3, healthy melon fruits were surface-sterilized with 70% ethanol and rinsed twice with sterile-distilled water. Then, the melons were wounded using a sterile inoculating needle to stab and inoculated by a mycelium agar plug of strain Fi-3 on the wound sites. 5 fruits were inoculated in each treatment, and a mycelium-free PDA plug was used as a negative control, repeated 3 times, at 25℃ with high relative humidity for 10 days. The results show disease symptoms similar to those naturally infected fruits on all inoculated melon fruits. The fungus re-isolated from the diseased fruits, showed the same colony morphology as the original isolate. Koch's postulates were repeated three times with the same results. Strain Fi-3 inoculated fruits without wounding remained healthy. To our knowledge, this is the first report of fruit rot of melon caused by F. pernambucanum in China.

Exploring airborne fungal contaminations and air quality pollution in nine ancient stone temples, Surin, Thailand.

This study provided crucial insights into the concentrations of airborne fungi, environmental parameters, and atmospheric pollution in Thailand's ancient stone temples. Airborne fungi were identified based on morphological characteristics. Airborne fungi, meteorological parameters, and atmospheric pollutants concurrently assessed during each sampling event, evaluating indoor/outdoor ratio. Prevalent genera included Penicillium (14.36%), Aspergillus (10.94%), Cladosporium (10.74%), Rhizopus (6.31%), and Fusarium (5.90%), with an average fungi concentration of 4884.46 ± 724.79CFU/m3. Eighteen fungal species out of the 64 airborne fungi identified were well-known serious pathogenic agents, contributing not only to structural deterioration but also to human health. Significant variations were observed between indoor and outdoor environments and across diverse landscapes, particularly for PM10 (ranging from 43.47 to 121.31µg/m3) and PM2.5 (ranging from 29.59 to 89.60µg/m3), with intensive incense burning identified as a prominent source of indoor atmospheric pollution. Historical temples, particularly situated in urban areas, were identified as significant reservoirs of airborne fungi. Correlations between meteorological parameters and pollutants revealed strong associations. Furthermore, principal component analysis (PCA) and cluster analysis elucidated distinct patterns in airborne fungal concentrations and contaminations. This study analyzed environmental factors, pollutants, airborne fungi, and geographical variations from July 2020 to March 2021. Understanding prevalent genera, airborne fungi concentrations, pathogenic species, biodeterioration, and environmental dynamics provided strategies for improving indoor air quality and mitigating airborne fungal contamination in archaeological buildings worldwide.

UV-mediated photochemical synthesis and investigation of the antiviral properties of Silver nanoparticle-polyvinyl butyral nanocomposite coatings as a novel antiviral material with high stability and activity

Effectively developing new antimicrobial surfaces for viral diseases requires considerable research, money, and time. Moreover, new species of microorganisms and pathogens are constantly appearing or entering from other regions, which can cause epidemics or pandemics. The ongoing presence of SARS-CoV-2 underscores the need to develop new antimicrobial materials. In this context, a novel UV-irradiated photochemical in-situ synthesis method is introduced for producing durable, long-lasting antiviral silver-polymer (AgNP-PVB) nanocomposite coatings. These coatings are intended to mitigate infectious disease transmission across various frequently touched surfaces, such as door handles, keypads, bank encoders, telephone locks, lift buttons, etc. Additionally, the significance of the size and concentration of AgNP in influencing the physical and antiviral properties of these nanocomposite coatings is illustrated. Detailed studies of AgNP-PVB coatings were conducted using X-ray diffraction, Raman spectroscopy, atomic force microscopy (AFM), and ultraviolet-visible-near-infrared spectroscopy, and contact angle measurements. The antiviral properties of the coatings were evaluated by a one-step reverse transcription real-time polymerase chain reaction (one-step qRT‒PCR) using synthetic SARS-CoV-2 RNA. Raman spectra signatures confirm AgNPs in the PVB matrix by matching identified peaks in X-ray diffractograms. AFM analysis revealed a reduction in AgNP size in the nanocomposite with an increase in the irradiation duration from 5 to 30 min. Spectroscopic results corresponding to AFM measurements highlighted specific wavelengths related to different AgNP size ranges. Contact angle measurements suggest that antiviral activity can be predicted by calculating the surface free energy (SFE) of the sample. As the SFE value increases, antiviral activity decreases. Nanocomposite coatings (with concentrations of 150, 200, 500, and 1000 ppm AgNP) are effective in reducing the activity of SARS-CoV-2, indicating their potential as long-acting preventive agents against viral infections. A methodology incorporating a specialized algorithm was devised for the application of the investigated coatings, which also integrates 3D scanning and printing techniques for fabricating complex geometry flexible protective cover. Subsequently, this coating was applied to produce a protective cover for the widely utilized public object, the door handle, employing 3D printing technology. As a result of the work, a long-term, durable antiviral AgNP-PVB nanocomposite coating with varying AgNP sizes (ranging from 15 to 118 nm) and concentrations (150, 200, 500, and 1000 ppm) was successfully developed.

Host–pathogen interaction between the African fig fly, Zaprionus indianus, and its external mycobiome under laboratory conditions

AbstractThe African fig fly, Zaprionus indianus Gupta (Diptera: Drosophilidae), is an ecologically diverse pest species that interacts with and feeds on various microbial pathogens including bacteria and yeast found in decomposing fruits. However, the interaction of Z. indianus with its microbial community and microbial pathogens is obscure. To determine the presence of fungal pathogens, we collected wild Z. indianus from the northwestern part of the Indian subcontinent. Based on molecular identification and phylogenetic analysis, Debaryomyces hansenii (Zopf) Lodder & Kreger‐van Rij (isolate ziha1) was the most commonly observed fungus associated with Z. indianus. Furthermore, we identified two more opportunistic fungal pathogens: Aspergillus flavus Link (isolate zias2), and Pichia kudriavzevii Boidin, Pignal & Besson (isolate zibd3). The interaction of isolated fungi with Z. indianus was evaluated in terms of larval mortality, adult emergence, and fecundity. Debaryomyces hansenii ziha1 resulted in 90% emergence rate for adults, and did not cause significant mortality in the larval stage. In contrast, A. flavus zias2 and P. kudriavzevii zibd3 showed a significant reduction in fecundity and caused 99% and 74% larval mortality of Z. indianus, respectively. In the laboratory oviposition preference assay, mated females of Z. indianus preferred D. hansenii ziha1 supplemented food with a positive oviposition index compared to the uninfected control and compared to food infected with P. kudriavzevii zibd3 or A. flavus zias2. These findings underscore Z. indianus' potential to act as a reservoir for both symbiotic and pathogenic fungal species, some of which may be further harnessed for effective fruit fly pest control strategies.

Magnetic Nanoagent Coated with an Activated Macrophage Membrane for Colorimetric Detection of Bacteria.

The construction of cell mimics replicating the surface landscape and biological functions of the cell membrane offers promising prospects for biomedical research and applications. Inspired by the inherent recognition capability of immune cells toward pathogens, we have fabricated activated macrophage membrane-coated magnetic silicon nanoparticles (aM-MSNPs) in this work as an isolation and recognition tool for enhanced bacterial analysis. Specifically, the natural protein receptors on the activated macrophage membrane endow the MSNPs with a broad-spectrum binding capacity to different pathogen species. By further incorporation of a tyramide amplification strategy, direct naked-eye analysis of specific bacteria with a detection limit of 10 CFU/mL can be achieved. Moreover, application to the diagnosis of urinary tract infections has also been validated, and positive samples spiked with bacteria can be clearly distinguished with an accuracy of 100%. This work may enrich cell membrane-based architectures and provide an experimental paradigm for point-of-care testing (POCT) detection of bacteria.