Bacterial Culture Research Articles

Upscaling Osteoclast Generation by Enhancing Macrophage Aggregation Using Hollow Microgels.

Osteoclasts, the bone resorbing cells of hematopoietic origin formed by macrophage fusion, are essential in bone health and disease. However, in vitro research on osteoclasts remains challenging due to heterogeneous cultures that only contain a few multinucleated osteoclasts. Indeed, a strategy to generate homogeneous populations of multinucleated osteoclasts in a scalable manner has remained elusive. Here, the investigation focuses on whether microencapsulation of human macrophages in microfluidically generated hollow, sacrificial tyramine-conjugated dextran (Dex-TA) microgels could facilitate macrophage precursor aggregation and formation of multinucleated osteoclasts. Therefore, human mononuclear cells are isolated from buffy coats and differentiated toward macrophages. Macrophages are encapsulated in microgels using flow focus microfluidics and outside-in enzymatic oxidative phenolic crosslinking, and differentiated toward osteoclasts. Morphology, viability, and osteoclast fusion of microencapsulated cells are assessed. Furthermore, microgels are degraded to allow cell sorting of released cells based on osteoclastic marker expression. The successful encapsulation and osteoclast formation of human macrophages in Dex-TA microgels are reported for the first time using high-throughput droplet microfluidics. Intriguingly, osteoclast formation within these 3D microenvironments occurs at a significantly higher level compared to the conventional 2D culture system. Furthermore, the feasibility of establishing a pure osteoclast culture from cell transfer and release from degradable microgels is demonstrated.

Metagenomic Analyses of Aerobic Bacterial Enrichment Cultures that Degraded Tris(2-chloroethyl) Phosphate (TCEP) and Its Transformation Products

Tris(2-chloroethyl) phosphate (TCEP) is of growing public concern worldwide because of its ubiquitous contamination, toxicity, and persistence. In this study, we investigated bacterial communities in aerobic enrichment cultures with TCEP and its two major transformation products bis(2-chloroethyl) phosphate (BCEP) and 2-chloroethanol (2-CE) as the sole carbon source. Burkholderiales and Rhizobiales were likely two main bacterial guilds involved in the hydrolysis of TCEP, while Rhizobiales and Sphingomonadales may play an important role in the hydrolysis of BCEP, given the increase of Rhizobiales and Sphingomonadales-related phosphoesterase genes when the carbon source was switched from TCEP to BCEP. All Burkholderiales, Rhizobiales, Sphingomonadales were probably efficient in 2-CE metabolism, because their dehydrogenase genes and dehalogenase genes increased after 2-CE enrichment. The different substrate preference of different bacterial guilds highlighted the importance to understand the diversity and collaboration among functional bacteria. Meanwhile, two TCEP-degrading strains affiliated with Xanthobacter and Ancylobacter were isolated. Xanthobacter sp. strain T2-1 was able to degrade both TCEP and BCEP following the pseudo-first-order kinetics with reaction rates of 1.66 h-1 for TCEP and 1.02 h-1 for BCEP, respectively. Ancylobacter sp. strain T3-4 could degrade TCEP following the pseudo-first-order kinetics with a reaction rate of 2.54 h-1, but is unable to degrade BCEP. Additionally, strains that were phylogenetically closely related were found to have different degradation capabilities toward TCEP and/or BCEP, indicating the importance to investigate functional genes such as phosphoesterase genes.

IL-6 and TIMP-1 Correlated to Airway Pathogen Colonization and Predict Disease Severity in Patients with Non-Cystic Fibrosis Bronchiectasis.

Non-cystic fibrosis bronchiectasis is associated with airway pathogen colonization. We planned to investigate the inflammatory markers in patients with different airway pathogens and their correlation with disease severity. We enrolled patients aged between 20 and 75 from October 2021 to August 2022. All patients had sputum evaluation for bacterial and fungal cultures before enrollment, and were classified into four groups according to the culture results. Forty-four patients with non-CF bronchiectasis and six controls were enrolled and categorized as follows: Group 1, no pathogens identified in sputum cultures (n = 14); Group 2, positive fungal culture results (n = 18); Group 3, positive P. aeruginosa culture results (n = 7); and Group 4, positive culture results for both fungi and P. aeruginosa (n = 5). Group 4 had significantly higher serum defensin α1, IL-6 and tissue inhibitors of MMP (TIMP)-1 levels than group 1 patients. The serum levels of IL-6 and TIMP-1 were positively correlated with the FACED score and negatively correlated with distance-saturation product. Significantly higher levels of serum IL-6 and TIMP-1 were found in the patients who had concomitant fungal and P. aeruginosa colonization, and were closely related to clinical severity and may have important roles in disease monitoring.

Resistance of Ascochyta rabiei isolates from chickpeas (Cicer arietinum L.) to fungicides

Ascochyta blight is a disease that causes significant yield losses in chickpea crops in Turkey under favorable environmental conditions. The fungal pathogen Ascochyta rabiei is the causative agent of this disease. The antifungal activity of previous fungicides against A. rabiei was not effective due to the heterothallic nature of the fungus. The aim of this study was to determine the sensitivity of A. rabiei to fungicides (25.2 g kgˉ1 boscalid + 12.8 g kgˉ1 pyraclostrobin; 50% tebuconazole + 25% trifloxystrobin; 62.5 g Lˉ1 propiconazole + 37.5 g Lˉ1 azoxystrobin; 80% thiram; 80% kükürt (sulphur); 80% mancozeb; 80% maneb) under in vitro and field conditions. Pure cultures of A. rabiei were isolated from infected chickpea plants collected in Boğazlayan, Sarıkaya, Sorgun, Merkez and Yerköy. A total of 14 A. rabiei isolates and 4 references were evaluated. The field test was conducted at Yozgat Bozok University, Yerköy Agricultural Application and Research Center Station. The trials began on March 14, 2021. The experimental area was divided into plots and the susceptible chickpea variety Sarı98 was used for the study. Two artificial inoculations were carried out approximately on the 40th and 80th days after sowing. Twenty-four hours after inoculation, the chickpea plants were sprayed with the fungicides Nativo® WG 75, Bellis®, Dikotan® M45 and Thiovit Jet® using a handheld sprayer. In vitro testing revealed that A. rabiei was resistant to kükürt (sulphur), thiram, maneb, and mancozeb. A field study showed that the percentage of A. rabiei isolates treated with the mancozeb fungicide was between 14 and 21% of the control. Therefore, effective disease management strategies should include not only the use of fungicides, but also alternative approaches such as the use of resistant varieties. Moreover, the study focused on phenotypic resistance and suggests that future research should investigate the genetic and molecular mechanisms underlying A. rabiei resistance to enable better resistance management.

Regeneration of tunic cuticle is suppressed in edible ascidian Halocynthia roretzi contracting soft tunic syndrome.

Soft tunic syndrome is an infectious disease caused by the flagellate Azumiobodo hoyamushi, which severely damages the aquaculture of the edible ascidian Halocynthia roretzi. Tunic is a cellulosic extracellular matrix entirely covering the body in ascidians and other tunicates, and its dense cuticle layer covers the tunic surface as a physical barrier against microorganisms. When the tunic of intact H. roretzi individuals was cut into strips, electron-dense fibers (DFs) appeared on the cut surface of the tunic matrix and aggregated to regenerate a new cuticular layer in seawater within a few days. DF formation was partially or completely inhibited in individuals with soft tunic syndrome, and DF formation was also inhibited by the presence of some proteases, indicating the involvement of proteolysis in the process of tunic softening as well as cuticle regeneration. Using pure cultures of the causative flagellate A. hoyamushi, the expression of protease genes and secretion of some proteases were confirmed by RNA-seq analysis and a 4-methylcoumaryl-7-amide substrate assay. Some of these proteases may degrade proteins in the tunic matrix. These findings suggest that the proteases of A. hoyamushi is the key to understanding the mechanisms of cuticular regeneration inhibition and tunic softening.

Mass production of Isaria fumosorosea pfu5 for community approach management of rugose spiraling whitefly in oil palm

The management of an alien Rugose spiraling whitefly (RSW) on oil palm using a native entomopathogenic fungus, Isaria fumosorosea pfu5 necessitated community approach for pest management. Moreover, coverage of huge leaf biomass warrants massive multiplication of biocontrol agent. In this communication, a two-step strategy, first including pure culture production and the second including ready-to-use culture production of the biocontrol agent is disclosed. The production costs and success of this technology in RSW management of oil palm are also discussed.

Application of the second-generation sequencing technology of metagenomics in the detection of pathogens in respiratory patients

ObjectiveTo explore the application value of the second-generation metagenomic next-generation sequencing (mNGS) in the detection of pathogens in patients with pulmonary infection. MethodsWe conducted a retrospective analysis of 65 pulmonary infection cases treated at our institution and the Fifth People's Hospital of Shanghai between January 2021 and May 2023. All subjects were subjected to mNGS, targeted next-generation sequencing (tNGS), and conventional microbiological culture. A comparative analysis was performed to evaluate the diversity and quantity of pathogens identified by these methodologies and to appraise their respective diagnostic capabilities in pulmonary infection diagnostics. ResultsThe mNGS successfully identified etiological agents in 60 of the 65 cases, compared to tNGS, which yielded positive results in 42 cases, and conventional laboratory cultures, which detected pathogens in 24 cases. At the bacterial genus level, mNGS discerned 9 genera, 11 species, and 92 isolates of pathogenic bacteria, whereas tNGS identified 8 genera, 8 species, and 71 isolates. Conventional methods were less sensitive, detecting only 6 genera, 7 species, and 33 isolates. In terms of fungal detection, mNGS identified 4 fungal species, tNGS detected 4 isolates of the Candida genus, and conventional methods identified 2 isolates of the same genus. Viral detection at the species level revealed 10 species and 46 isolates by mNGS, whereas tNGS detected only 3 species and 7 isolates. The area under the receiver operating characteristic curve (AUC) with 95% confidence intervals for diagnosing pulmonary infections was 0.818 (0.671 to 0.966) for mNGS, 0.668 (0.475 to 0.860) for tNGS, and 0.721 (0.545 to 0.897) for conventional culture.The mNGS demonstrates superior diagnostic efficacy and pathogen detection breadth in critically ill patients with respiratory infections, offering a significant advantage by reducing the time to diagnosis. The enhanced sensitivity and comprehensive pathogen profiling of mNGS underscore its potential as a leading diagnostic tool in clinical microbiology.

Antimicrobial prescribing in referral hospitals in Timor-Leste: results of the first two national point prevalence surveys, 2020-21.

To describe antimicrobial use (AMU) in patients admitted to hospitals in Timor-Leste. In 2020 and 2021, we undertook antimicrobial prescribing point prevalence surveys across all six hospitals in Timor-Leste (one national and five municipal) to describe AMU and appropriateness in admitted patients. In 2020, 291/394 (73.9%) surveyed patients had been prescribed antimicrobials, compared with 260/403 (64.5%) in 2021 (P = 0.004). Most (309/551; 56.1%) were prescribed one antimicrobial, and 179/551 (32.5%) were prescribed two. The most commonly prescribed antibiotics were ceftriaxone (38.5% in 2020, 41.5% in 2021) and ampicillin (35.7% in 2020, 32.3% in 2021), followed by gentamicin, metronidazole and cloxacillin. Reserve antibiotics like meropenem and vancomycin were minimally used. Of all antimicrobial prescriptions, 70.8% were deemed appropriate in 2020 and 69.1% in 2021. Antimicrobial prescriptions for surgical and post-partum prophylaxis were frequently deemed inappropriate [37/50 (74.0%) and 39/44 (88.6%) prescriptions, respectively]. Most patients admitted to hospital in Timor-Leste are prescribed antimicrobials, and approximately one-third of these prescriptions are inappropriate. However, this was in the context of limited local guideline availability at the time of surveys and limited microbiological culture capacity outside of the capital, Dili. Improved microbiological guidance, iterative guideline revisions based on local antimicrobial resistance (AMR) surveillance data, and enhanced stewardship activities including further point prevalence studies, could improve antimicrobial use, optimize patient outcomes and reduce AMR in Timor-Leste.

Clinical Study on the treatment of chronic infectious ulcers using Platelet-Rich technology combined with moist dressings.

To explore the clinical efficacy of platelet-rich technology combined with moist dressings in the treatment of chronic infectious ulcers. This was a retrospective study. The subjects of the study were 48 patients with chronic infectious ulcers in Sichuan Provincial Orthopedics Hospital from January 2019 to June 2022. Enrolled patients were randomly divided into four groups(n=12), and received different treatment methods respectively. Further analysis and comparison were performed on the changes in wound volume, wound healing status, wound bacterial culture results, and the incidence of adverse reactions among the four groups. Three months after debridement, the wound volume of all four groups of patients was significantly reduced compared with that before debridement, with a statistically significant difference in intra-Group-Comparison(P<0.05). The inter-Group-Comparison revealed a statistically significant difference in wound volume in Group-A, Group-B, and Group-C than that in Group-D(P<0.05). After treatment, the wound healing status of patients in groups A, B, and C was significantly better than that of patients in Group-D, with a statistically significant difference(P<0.05). During treatment, patients in all four groups had decreased count of would bacteria, and showed negative results of wound bacterial culture by the three-month follow-up. No serious adverse reactions were observed in the four groups during treatment, and all improved after management, with no statistically significant difference in the incidence of adverse reactions(P>0.05). Platelet-rich technology combined with moist dressings may effectively promote the repair of chronic infectious ulcer wounds, with good clinical safety.

Respiratory viral infections in children with cancer and febrile neutropenia and children undergoing hematopoietic stem cell transplantation.

The scope of this review is to understand the epidemiology and potential role of respiratory viral infections in children with cancer and febrile neutropenia, as well as in children, undergoing hematopoietic stem cell transplantation. Early detection of respiratory viral infections through molecular diagnostic techniques has allowed recent randomized clinical studies to advance the possibility of more rational use of antimicrobials in this susceptible population. Progress has been made in the early detection of respiratory viruses in episodes of fever and neutropenia in children with cancer. In selected patients who meet specific clinical safety criteria and have negative bacterial cultures, it has been possible to safely and effectively discontinue antimicrobials. This has been validated in recent randomized clinical studies. However, more evidence is still needed for a similar indication in children, undergoing hematopoietic stem cell transplantation with viral respiratory infection episodes. Understanding the role of respiratory viral infections in populations of immunocompromised children may contribute to a more rational use of antimicrobials and, in the near future, may help to decrease antimicrobial resistance in this susceptible population.

Effective biocontrol efficacy of Bacillus subtilis CV21 against cherry leaf spot disease caused by Alternaria phytopathogens and growth promotion of flowering cherry (Prunus sargentii Rehder) seedlings

Cherry leaf spot (CLS) disease is one of the most common and deleterious disease of flowering cherry seedlings which lowers frost tolerance, growth, and biomass production during the season, and reduces flower production in following season. This study isolated two phytopathogens, Alternaria alternata CH3 and Alternaria alternata CH10, and confirmed their pathogenicity of CLS disease in flowering cherry seedlings, causing brownish spots and necrotic lesions on the leaves. We also isolated a plant growth-promoting bacteria (PGPB), Bacillus subtilis strain CV21, and investigated its antifungal and plant growth-promoting properties. The bacterium produced cell wall-degrading enzymes such as chitinase, β-1,3-glucanase, and protease and effectively antagonized both A. alternata CH3 and A. alternata CH10 and the crude enzyme fraction (100 µl/mL) of B. subtilis CV21 inhibited spore germination by 40.1 % and 25.1 % and reduced mycelial growth by 29.1 % and 42.5 % against A. alternata CH3 and A. alternata CH10. The crude enzyme fraction degraded the cell walls of both phytopathogens in a concentration-dependent manner, causing swelling with bulbous structures in the hyphal cell, and cell wall lysis with severe perforations, loss of shape and aggregation of spores compared to control. Treatment with the bacterial culture broth on flowering cherry seedlings reduced CLS disease by 1.3-fold and 3.4-fold compared to the chemical treatment and the control group, respectively. In addition, B. subtilis CV21 also demonstrated plant growth-promoting properties such as indole-3-acetic acid (IAA) production up to a maximum concentration of 3.5 µg/mL during the experimental period and exhibited potential for phosphate solubilization and nitrogen fixation. The inoculation of nursery seedlings with B. subtilis CV21 culture broth improved the chlorophyll content, and increased seedling growth and biomass production compared to chemical treatment and the control group. The results demonstrate that the B. subtilis CV21 could be effectively applied as a bio-fungicide to control CLS and as bio-stimulant/bio-fertilizer to enhance the growth of flowering cherry seedlings.

Divergent dual C-H isotopic fractionation pattern during anaerobic biodegradation of toluene within Aromatoleum species under nitrate-reducing conditions

Toluene is a pollutant frequently detected in contaminated groundwater, mostly due to leakage from underground gasoline storage tanks and pipeline ruptures. Multi-element compound-specific isotope analysis provides a framework to understand transformation processes and design efficient remediation strategies. In this study, we enriched an anaerobic bacterial culture derived from a BTEX-contaminated aquifer that couples toluene and phenol oxidation with nitrate reduction and the concomitant production of carbon dioxide and biomass. The 16S rRNA gene amplicon data indicated that the toluene-degrading consortium was dominated by an Aromatoleum population (87 ± 2 % relative abundance), and metagenome sequencing confirmed that the genome of this Aromatoleum sp. encoded glycyl-radical enzyme benzylsuccinate synthase (BssABC) and phenylphospate synthase (PpsA1BC) homologous genes involved in the first step of toluene and phenol transformation, respectively. Carbon and hydrogen isotopic fractionation were εbulk, C = - 3.5 ± 0.6 ‰ and εrp, H = - 85 ± 11 ‰, respectively, leading to a dual C-H isotope slope of ΛH/C = 26 ± 2. This value fits with a previously reported value for a consortium dominated by an Azoarcus species (ΛH/C = 19 ± 5) but differs from that reported for Aromatoleum aromaticum (ΛH/C = 14 ± 1), both of which grow with toluene under nitrate-reducing conditions. Overall, this suggests the existence of different BssABC enzymes with different mechanistic motifs even within the same Aromatoleum genus.

Verapamil Enhances the Activity of Caspofungin against Cryptococcus neoformans Coincides with Inhibited Ca2+ /CN Pathway and Damage with Cell Wall Integrity

Currently, the therapeutic effect on cryptococcal infection patients is hindered by toxicity and drug resistance, making it urgent to discover alternative antifungals. Calcium channel blockers, verapamil (VER), have shown effective antifungal effects in several fungi. Here, we found that VER has a significant antifungal effect on Cryptococcus neoformans (C. neoformans). Furthermore, VER has significant synergistic effects with multiple antifungals, even caspofungin (CAS). We confirmed that VER and CAS had a synergistic antifungal effect in the Galleria mellonella.We conducted in-depth research on the possible mechanism of the synergistic impact of VER and CAS. After treatment with VER, the chitosan content of C. neoformans ' cell wall decreased and in dopamine liquid culture medium, we observed the leakage of melanin. Through cell wall fluorescence staining and stress sensitivity analysis, we further demonstrated that VER impaired the integrity of the C. neoformans' cell wall. Another side, VER+CAS modification of C. neoformans membrane permeability, leading to intracellular ROS accumulation and mitochondrial membrane potential changes. VER eliminated the cytoplasmic calcium fluctuations caused by CAS stimulation and down-regulated the genes expression associated with the calcineurin pathway. In addition, we found that the enzyme activity of chitin deacetylase of C. neoformans is significantly influenced by the presence of Ca2+, suggesting that the use of VER may affect the activity. In summary, the synergistic antifungal effect of VER and CAS makes them effective and promising candidates for fungal treatment.

First report of Alternaria crassa causing yellow spots on Daturastramonium in China.

DaturastramoniumL.(jimson weed)is an invasiveweedin agricultural fieldsand a medicinalplant. In April 2022, a leaf disease on D. stramonium was observed in Zhanjiang (21.17 N, 110.18 E), Guangdong province, China. Early symptoms were small yellow spots on leaves. Later, the spots gradually expanded and turned becoming necrotic with a clear yellow halo and a white center. The disease incidence in the field was 85% (n= 50, about 1 ha). Twenty diseased leaves were collected from the field. The margin of the diseased tissues was cut into 2 mm × 2 mm pieces, surface disinfected with 75% ethanol and 2% sodium hypochlorite for 30 and 60 s, respectively, and rinsed twice with sterile water before isolation. The tissues were plated onto potato dextrose agar (PDA) medium and incubated at 28 ℃. After 2-day incubation, grayish fungal colonies appeared on the PDA, then pure cultures were produced by transferring hyphal tips to new PDA plates. Single-spore isolation method was used to recover pure cultures for three isolates (DSAC-1, DSAC-2, and DSAC-3). The isolates were morphologically identical.They colonies were gray to brownish black. Conidiophores were branched, brown. Conidia were brown, long ellipsoid, had 4-12 transverse and 0-3 longitudinal septa; measured within 67.5-127.8 (average =105.6) × 12.5-27.8 (average=20.4) µm (n=30). Apical beak was longer than conidia body. measured within 40.5-423.5 (average =365.2) × 2.5-5.8 (average=3.2) µm (n=30). Based on morphological characteristics, the three isolates were identified asAlternariacrassa(Sacc.) Rands (Simmons 2007). Molecular identification was performed using the colony polymerase chain reaction method with MightyAmp DNA Polymerase (Takara-Bio, Dalian, China) (Lu et al. 2012) to amplify internal transcribed spacer (ITS) region, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), RNA polymerase second largest subunit (RPB2) and translation elongation factor (TEF1) with primers of ITS1/ITS4, GDF1/GDR1, RPB2-5F2/fRPB2-7cR, and EF-1α-F/EF-1α-R, respectively (Walther et al. 2013; Woudenberg et al. 2015; Nishikawa and Nakashima. 2020). Amplicons of the isolates were sequenced and submitted to GenBank (ITS, ON430524-ON430526; GAPDH, ON500656-ON500658; RPB2, ON500659-ON500661; TEF1, ON500662-ON500664). The sequences were 100% identical with those of Alternaria crassa strain CBS 116647 upon BLAST analysis. The sequences were also concatenated for phylogenetic analysis by maximum likelihood. The isolates clustered withA. crassa (CBS 116647, CBS 116648, CBS CBS-110.38, and CBS_103.18 ).Thus, the fungus associated with leafyellow spoton D. stramonium was identified asA. crassa.Pathogenicity tests were conducted in a greenhouse at 24℃-30℃ with 80% relative humidityusing 3 isolates. Individual plants were grown in pots (n = 5, 1 month old). The unwounded leaflets were inoculated using three isolates (DSAC-1, DSAC-2, and DSAC-3). The fungal mycelium on 5 mm-diameter PDA plugs were placed faced down to the leaves. Sterile PDA was used for mock inoculated comtrols.. The test was performed three times. Disease symptoms were observed on the leaves after 7 days, whereas the controls remained healthy. The pathogen was re-isolated from infected leaves and was morphologically identical to the original isolates, fulfilling Koch's postulates.A. crassa was reported causing leaf spot on D. stramonium in Algeria (Nabahat et al. 2020). To our knowledge, this report is the first report of A. crassa causing leaf yellow spot on D. stramonium in China. This pathogen possessespotential biocontrol properties on the invasiveweed, while this study also provides an important reference for the control of the diseaseof the medicinalplant.

First Report of Colletotrichum gloeosporioides Causing Leaf Blight on Cercis chinensis Bunge in China.

Cercis chinensis Bunge, commonly used as an ornamental plant, is native to southeastern China and extensively cultivated in gardens across major cities in the country. In August 2023, a new high-incidence disease was discovered at Huangshan University in Huangshan, Anhui Province, China. The symptoms initially began as small brown spots, which gradually expanded into large irregular brown spots with black-brown edges. The disease was investigated at both Jilingshan Park and Huangshan University, where C. chinensis Bunge was planted, revealing an average incidence rate of was 85 % at these sites. Seventy two leaf tissue samples (3 to 4 mm²) were collected from the margins of the lesion and subjected to surface sterilization with 75% ethanol for 30 seconds followed by 1% sodium hypochlorite for 90 seconds. Subsequently, the tissues were rinsed with sterile H2O, placed on potato dextrose agar (PDA) medium, and incubated at 25℃ for 5 days. The same fungus was isolated from 90% of the tissues, and pure cultures were obtained by monosporic isolation. Representative isolates ZJ 2-1, ZJ 2-2 and ZJ 2-3 were selected for morphological and molecular characterization. The colonies displayed a color range from white to gray, with white margins and aerial hyphae, while the reverse side of the colonies appeared gray to brown. Conidia were cylindrical, aseptate, with obtuse to slightly rounded ends, measuring 15.8±1.8×4.7±0.56 μm (n = 50). The morphological characteristics were generally consistent with those of Colletotrichum gloeosporioides species complex (Weir et al. 2012). Five conserved regions of isolates (ZJ 2-1, ZJ 2-2 and ZJ 2-3), including the internal transcribed spacer (ITS), glutamine synthase (GS), calmodulin (CAL), actin (ACT), and chitin synthase 1(CHS1) gene regions, were amplified using specific primers ITS1/ITS4 (Gardes et al. 1993), GSR1/GSF1 (Guerber et al. 2003), CL1C/CL2C (Li et al. 2018), ACT-512F/ACT-783R, and CHS-79F/CHS-345R (Zhu et al. 2019), respectively. Using the BLAST, ITS, GS, CAL, ACT and CHS1 gene sequences (GenBank accession nos. PP514751, PP448025, PP448026, PP448027 and PP448028, respectively) were 100% (594 out of 594 bp), 100% (864 out of 864 bp), 100% (299 out of 299 bp), 100% (732 out of 732 bp) and 100% (282 out of 282 bp) identical to C. gloeosporioides (GenBank accession nos. JX010152, JX010085, JX009818, JX009731 and JX009531, respectively). A Maximum Likelihood phylogenetic tree, constructed by combining all sequenced loci in MEGA7, showed that the isolates ZJ 2-1, ZJ 2-2 and ZJ 2-3 clustered within the C. gloeosporioides clade with 99% bootstrap support (Fig. S1). To fulfill Koch's postulates, five C. chinensis Bunge plants were tested for pathogenicity in the field with isolates ZJ 2-1, ZJ 2-2 and ZJ 2-3 at Huangshan University. Twelve leaves from each tree were wounded and inoculated with mycelial plugs (approximately 4 mm in diameter) and 10 μl of a spore suspension (1.0 × 106 conidia/ml) of C. gloeosporioides. Inoculation with sterile PDA plugs and pure water on leaves of each tree served as negative controls. Plastic bags were used to wrap the leaves, and sterile H2O was sprayed into the bags to maintain moisture conditions (Zhang et al.2020). The experiment was repeated two times, and within 5 days, all inoculated points displayed lesions similar to those observed in the field, whereas controls remained asymptomatic (Fig. S2). The same fungus was reisolated from these lesions with a frequency of 100%. Consequently, the pathogen responsible the disease in C. chinensis Bunge was identified as C. gloeosporioides. To the best of our knowledge, this is the first report of C. gloeosporioides causing leaf blight on C. chinensis Bunge in China. This study provides valuable insights for implementing targeted measures to control leaf blight on C. chinensis Bunge and lays a foundation for the prevention and treatment of the disease.

Aspergillus Cell Surface Structural Analysis and Its Applications to Industrial and Medical Use

The hyphal surface of cells of filamentous fungi is covered with cell wall, which is mainly composed of polysaccharides. Since the cell wall is the first structure to come in contact with the infection host, the environment, and the fungus itself, the elucidation of the cell wall structure and biogenesis is essential for understanding fungal ecology. Among filamentous fungi, the genus Aspergillus is an important group in the industrial, food, and medical fields. It is known that Aspergillus species form hyphal pellets in shake liquid culture. The authors previously found the role of α-1,3-glucan in hyphal aggregation in Aspergillus species. In addition, extracellular polysaccharide galactosaminogalactan contributed to hyphal aggregation as well, and dual disruption of biosynthesis genes of α-1,3-glucan and galactosaminogalactan resulted in complete hyphal dispersion in shake liquid culture. The characteristic of mycelia to form pellets under liquid culture conditions was the main reason why the growth measurement methods used for unicellular organisms could not be applied. We reported that hyphal growth of the dual disruption mutant could be measured by optical density. A real-time plate reader could be used to determine the growth curve of the mycelial growth of the dual disruption mutant. This measurement approach not only provides basic microbiological insights in filamentous fungi, but also has the potential to be applied to high-throughput screening of anti-Aspergillus drugs.

Clinical significance of lower respiratory tract culture within 48 h of admission in patients with viral pneumonia: an observational study

BackgroundThe aim of this retrospective study was to examine the risk factors of positive lower respiratory tract cultures and to investigate whether nosocomial infections are common in patients with positive lower respiratory tract cultures.MethodsWe enrolled 86 patients diagnosed with influenza A-related critical illness who were treated at Fuzhou Pulmonary Hospital of Fujian in China between 1st October 2013 and 31st March 2019. The of admission were used to divide the enrolled patients into two groups. Sputum and bronchoalveolar lavage fluid specimens were collected within 48 h after admission for culture. All samples were cultured immediately after sampling. Nosocomial infections are defined as any symptom or sign of pulmonary infiltration, confirmed by X-ray, after 5 days of admission and positive results from one or more cultures.ResultsThe average age of this cohort was (54.13 ± 16.52) years. Based on the culture results, Staphylococcus aureus and Candida albicans had the highest positive rates (3.40% (3/86) and 20.90% (18/86), respectively). In patients with positive lower respiratory tract cultures, the incidence of nosocomial infection was 73.30% (22/30) five days after admission. However, the incidence of nosocomial infection was lower (42.80%, 24/56) in patients with negative lower respiratory tract cultures. Hemoptysis, systolic pressure at admission, and blood urea nitrogen level at admission were all independent risk factors for positive lower respiratory tract cultures within 48 h of admission.ConclusionOur data showed that a significant proportion of patients with pneumonia exhibited co-infections with bacteria or fungi within five days of hospital admission. Hemoptysis, systolic pressure, and blood urea nitrogen levels at admission emerged as the key risk factors. These findings underscore the necessity of closely monitoring patients with influenza infection, particularly for positive bacterial or fungal cultures within the initial 48 h of admission.

Gut microbiota carcinogen metabolism causes distal tissue tumours.

Exposure to environmental pollutants and human microbiome composition are important predisposition factors for tumour development1,2. Similar to drug molecules, pollutants are typically metabolized in the body, which can change their carcinogenic potential and affect tissue distribution through altered toxicokinetics3. Although recent studies demonstrated that human-associated microorganisms can chemically convert a wide range of xenobiotics and influence the profile and tissue exposure of resulting metabolites4,5, the effect of microbial biotransformation on chemical-induced tumour development remains unclear. Here we show that the depletion of the gut microbiota affects the toxicokinetics of nitrosamines, which markedly reduces the development and severity of nitrosamine-induced urinary bladder cancer in mice6,7. We causally linked this carcinogen biotransformation to specific gut bacterial isolates in vitro and in vivo using individualized bacterial culture collections and gnotobiotic mouse models, respectively. We tested gut communities from different human donors to demonstrate that microbial carcinogen metabolism varies between individuals and we showed that this metabolic activity applies to structurally related nitrosamine carcinogens. Altogether, these results indicate that gut microbiota carcinogen metabolism may be a contributing factor for chemical-induced carcinogenesis, which could open avenues to target the microbiome for improved predisposition risk assessment and prevention of cancer.

Anti-inflammatory potential of low-molecular-weight and high-sulfation-degree sulfated polysaccharides extracted from Antrodia cinnamomea

Two novel sulfated polysaccharides (SPs), N10 and K5 were isolated from ammonium sulfate or potassium sulfate at concentrations of 10 mM and 5 mM in liquid cultures of Antrodia cinnamomea, respectively. N10 and K5 were galactoglucans with a galactose:glucose molar ratio of approximately 1:3. In lipopolysaccharide (LPS)-stimulated RAW264.7 cells, N10 and K5 exhibited strong anti-inflammatory potential, of 56 % and 23 % maximal inhibition of IL-6 and TNF-α production, respectively. Mechanical analysis revealed differences between N10 and K5, with N10 inhibiting the LPS-stimulated phosphorylation of ERK and p38 in RAW264.7 cells. K5 inhibited the LPS-stimulated phosphorylation of AKT and TGFβR-II. N10 and K5 were fragmented into F1, F2, and F3, the molecular weights of which were 455, 24, 0.9, and 327, 36, 1.9 kDa, respectively. K5 F2 and K5 F3 exhibited high degrees of sulfation of 1:3 and 1:8, resulting in strong anti-inflammation, of 83 % and 37 % highest inhibition of IL-6 and TNF-α production, respectively. Therefore, low-molecular-weight and high-sulfation-degree SPs exhibited strong anti-inflammatory activity. Specifically, K5 F2 inhibited the phosphorylation of p38, and K5 F3 suppressed the signaling pathway of p38/JNK. Overall, the sulfation degree of SPs is concluded to affect the anti-inflammatory responses.

Prosthetic joint infection caused by Mediterraneibacter gnavus following total knee arthroplasty, challenges in anaerobic bacteria identification

BackgroundMediterraneibacter gnavus is a Gram positive, non-sporulated, obligate anaerobe diplococci. It was first described in 1974 by Moore et al. (under the name Ruminococcus gnavus) from faeces and contents of the gastrointestinal tract of humans. It is a relatively common member of the human gut microbiota, nevertheless its role as a pathogenic bacterium has not been completely elucidated yet and it seems to depend on numerous factors, including those of the host. Here we present a case of prosthetic joint infection following total knee arthroplasty by M. gnavus.Case presentationA 74 years old patient was admitted to the emergency department presenting with acute onset of left knee pain and swelling 20 days after total left knee arthroplasty. Follow-up revealed erythema and oedema without signs of fluctuation or purulent discharge from the surgical wound and elevated inflammatory reactants. Synovial fluid was taken for bacterial culture and antibiotic treatment with ceftazidime and daptomycin was established. Examination of the synovial fluid revealed abundant polymorphonuclear leucocytes, without visualizing bacteria. After four days of incubation, anaerobic culture exhibit growth of small, grey, umbilicated colonies in pure culture on Schaedler agar. The microorganism was identified as R. gnavus by MALDI-TOF (Bruker Daltonics) and M. gnavus by 16S ribosomal bacterial sequencing. The isolated showed susceptibility to the most commonly used anaerobicidal antibiotics except for clindamycin. Surgical treatment and infection source control included DAIR (debridement, antibiotics, and implant retention) and vacuum assisted therapy. The patient was discharged after six weeks with a 3-month course of oral amoxicillin as consolidation therapy. Subsequent follow-up revealed adequate wound healing with no signs of infection.ConclusionsMediterraneibacter gnavus have been reported as the causal microorganism in a range of human infections, nevertheless its identification remains challenging. Infection of prosthetic joints by anaerobic microorganisms is uncommon and is not considered in its empirical antibiotic treatment, thus, correct and swift identification of anaerobic bacteria in these cases is paramount.