Search Results (156)

This study analyzed the heavy metal tolerance and chromium reduction and the potential of plant growth to promote Rhizobium sp. OS-1. By genetic makeup, the Rhizobium strain is nitrogen-fixing and phosphate-solubilizing in metal-contaminated agricultural soil. Among the Rhizobium group, bacterial strain OS-1 showed a significant tolerance to heavy metals, particularly chromium (900 µg/mL), zinc (700 µg/mL), and copper. In the initial investigation, the bacteria strains were morphologically short-rod, Gram-negative, appeared as light pink colonies on media plates, and were biochemically positive for catalase reaction and the ability to ferment glucose, sucrose, and mannitol. Further, bacterial genomic DNA was isolated and amplified with the 16SrRNA gene and sequencing; the obtained 16S rRNA sequence achieved accession no. HE663761.1 from the NCBI GenBank, and it was confirmed that the strain belongs to the Rhizobium genus by phylogenetic analysis. The strain’s performance was best for high hexavalent chromium [Cr(VI)] reduction at 7–8 pH and a temperature of 30 °C, resulting in a total decrease in 96 h. Additionally, the adsorption isotherm Freundlich and Langmuir models fit best for this study, revealing a large biosorption capacity, with Cr(VI) having the highest affinity. Further bacterial chromium reduction was confirmed by an enzymatic test of nitro reductase and chromate reductase activity in bacterial extract. Further, from the metal biosorption study, an Artificial Neural Network (ANN) model was built to assess the metal reduction capability, considering the variables of pH, temperature, incubation duration, and initial metal concentration. The model attained an excellent expected accuracy (R² > 0.90). With these features, this bacterial strain is excellent for bioremediation and use for industrial purposes and agricultural sustainability in metal-contaminated agricultural fields. Full article

A novel cellulose-degrading bacterial strain, D3-1, capable of degrading cellulose under medium- to high-temperature conditions, was isolated from soil samples and identified as Staphylococcus caprae through 16SrRNA gene sequencing. The strain’s cellulase production was optimized by controlling different factors, such as pH, temperature, incubation period, substrate concentration, nitrogen and carbon sources, and response surface methods. The results indicated that the optimal conditions for maximum cellulase activity were an incubation time of 91.7 h, a temperature of 41.8 °C, and a pH of 4.9, which resulted in a maximum cellulase activity of 16.67 U/mL, representing a 165% increase compared to pre-optimization levels. The above experiment showed that, when maize straw flour was utilized as a natural carbon source, strain D3-1 exhibited relatively high cellulase production. Furthermore, gas chromatography–mass spectrometry (GC-MS) analysis of products in the degradation liquid revealed the presence of primary sugars. The results indicated that, in the denitrification of simulated sewage, supplying maize straw flour degradation liquid (MSFDL) as the carbon source resulted in a carbon/nitrogen (C/N) ratio of 6:1 after a 24 h reaction with the denitrifying strain WH-01. The total nitrogen (TN) reduction was approximately 70 mg/L, which is equivalent to the removal efficiency observed in the glucose-fed denitrification process. Meanwhile, during a 4 h denitrification reaction in urban sewage without any denitrifying bacteria, but with MSFDL supplied as the carbon source, the TN removal efficiency reached 11 mg/L, which is approximately 70% of the efficiency of the glucose-fed denitrification process. Furthermore, experimental results revealed that strain D3-1 exhibits some capacity for nitrogen removal; when the cellulose-degrading strain D3-1 is combined with the denitrifying strain WH-01, the resulting TN removal rate surpasses that of a single denitrifying bacterium. In conclusion, as a carbon source in municipal sewage treatment, the degraded maize straw flour produced by strain D3-1 holds potential as a substitute for the glucose carbon source, and strain D3-1 has a synergistic effect with the denitrifying strain WH-01 on TN elimination. Thus, this research offers new insights and directions for advancement in environmental sewage treatment. Full article

During field surveys carried out in 2021 at two farms in Lombardy (North Italy), leaf samples were collected from 113 plants (both symptomatic and asymptomatic) belonging to 18 medicinal and aromatic species. Amplification and nucleotide sequence analyses of the 16S rRNA gene revealed the presence of ‘Candidatus Phytoplasma solani’ (subgroup 16SrXII-A) in 69 plants (61% infection rate) belonging to 14 of the 18 examined species. Among the 14 infected species, only Nepeta cataria L. exhibited symptoms including leaf and stem reddening. Molecular typing analyses showed that ‘Ca. P. solani’ strains identified in this study constitute a genetically homogeneous population, carrying the stamp gene sequence variant St5 and the new vmp1 gene sequence variant Vm93. Phylogenetic analyses showed that ‘Ca. P. solani’ strain St5/Vm93 belongs to the cluster b-II, associated with the bindweed-related pathosystem. In silico-translated Vmp1 protein sequence alignment suggested that ‘Ca. P. solani’ strain St5/Vm93 could be generated by recombination events between ‘Ca. P. solani’ strains co-infecting the same host. The results suggested future research investigating the diffusion and the ecology of ‘Ca. P. solani’ strain St5/Vm93 in agroecosystems (including other crops), and its effect on the composition of biologically active compounds in aromatic and medicinal plants. Full article

Phytoplasma (“Candidatus Phytoplasma” species) diseases have been reported globally to severely limit the productivity of a wide range of economically important crops and wild plants causing different yellows-type diseases. With new molecular detection techniques, several unknown and known diseases with uncertain etiologies or attributed to other pathogens have been identified as being caused by Phytoplasmas. In Africa, Phytoplasmas have been reported in association with diseases in a broad range of host plant species. However, the few reports of Phytoplasma occurrence in Africa have not been collated together to determine the status in different countries of the continent. Thus, this paper discusses the geographical distribution, detection techniques, insect vectors, alternative hosts and socio-economic impacts of Phytoplasma diseases in Africa. This is to create research perspectives on the disease’s etiology in Africa for further studies towards identifying and limiting their negative effects on the continent’s agricultural economy. In Africa, Phytoplasmas recorded in different countries affecting different crops belong to eight groups (16SrI, 16SrII, 16SrIII, 16SrIV, 16SrVI, 16SrXI, 16SrXIV and 16SrXXII) out of the 37 groups and over 150 subgroups reported worldwide on the basis of their 16S rRNA RFLP profile. Lethal yellow disease was the most destructive Phytoplasma reported in Africa and has a high socio-economic impact. Full article

Phytoplasmas of the X-disease group (16SrIII) are economically significant pathogens in South America, causing severe crop losses. Traditional classification based on the 16S rRNA gene has limitations in resolving closely related strains, prompting the exploration of alternative markers. This study focuses on the immunodominant membrane proteins imp and idpA, which exhibit high variability and play crucial roles in host–pathogen interactions. Through molecular characterization of imp and idpA genes in 16SrIII subgroups, we identified significant genetic diversity and distinct evolutionary pressures. The imp gene, under positive selection, showed high variability in its hydrophilic extracellular domain, suggesting adaptation to host immune responses. In contrast, idpA exhibited strong negative selection, indicating functional conservation. Phylogenetic analyses revealed that imp and idpA provide higher resolution than the 16S rRNA gene, enabling finer differentiation within subgroups. These findings highlight the potential of imp and idpA as complementary markers for phytoplasma classification and diagnostics. Full article

ACLF is a severe stage of liver cirrhosis, characterized by multiple organ failure, systemic inflammation, and high short-term mortality. The intestinal microbiota (IM) influences its pathophysiology; however, there are currently no studies in Latin American populations. Therefore, we analyzed IM and its relationships with sepsis, organ failure, and mortality. In parallel, we quantified serum lipopolysaccharides as a marker of bacterial translocation. Fecal samples from 33 patients and 20 healthy controls (HCs) were obtained. The IMs were characterized by 16S-rRNA amplicon sequencing, the metagenomic functional predictive profiles were analyzed by PICRUSt2, and LPS quantification was performed by ELISA. Patients with ACLF showed significant alterations in alpha and beta diversity compared to the HCs. A strong dominance index accurately predicted 28-day and 90-day mortalities. The IMs showed a polarization toward Proteobacteria associated with increased LPS. The LPS correlated with clinical severity, organ dysfunction, and higher pathogenic taxa. The Klebsiella/Faecalibacterium ratio showed good performance in identifying sepsis (AUROC = 0.83). Furthermore, Morganella, Proteus, and Klebsiella were enriched in patients with multiorgan failure. Lactobacillus, Escherichia/Shigella, Veillonella, and Ruminococcus gnavus exhibited potential in predicting 28- and 90-day mortalities. The IM alterations in ACLF may be useful as clinical biomarkers of poor prognosis, primarily for mortality and sepsis. These findings are representative of western Mexico. Full article

The psychrophilic aerobic heterotrophic bacterium, strain 1639^T, was isolated from the low-temperature Lake Untersee in Antarctica. The bacterium was Gram-positive, non-motile, yellow–green-pigmented, non-spore-forming, and a pleomorphic rod. Growth was observed at temperatures of 0–25 °C with an optimum at 10 °C. The strain used urea as a nitrogen source. The major fatty acids were i-C_16:0 (49.69%), ai-C_15:0 (17.59%), and C_16:1 branched (12.03%). Identified polar lipids were phosphatidylglycerols and a glycolipid. The respiratory quinone was determined to be MK-10. The genomic DNA G+C content was 68.03 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 1639^T was a member of the genus Cryobacterium, with the highest sequence similarity to C. arcticum SK1^T (98.4%), C. soli GCJ02^T (98.4%), C. lactosi Sr59^T (98.3%), C. zongtaii TMN-42^T (98.2%), and C. adonitolivorans RHLS22-1^T (98.1%). The ANI and the DNA–DNA hybridization estimate values between strain 1639^T and all type strains of species of the genus Cryobacterium were in the range of 84.3–87.8% and 20.5–40.3%, respectively. The combined genotypic and phenotypic data indicate that strain 1639^T represents a novel species within the genus Cryobacterium, for which the name Cryobacterium inferilacus sp. nov. is proposed with the type strain 1639^T (=KCTC 59142^T, =VKM Ac-2907^T, UQM 41460^T). Full article

In Graneros, O’Higgins Region, Chile, the mallow psyllid (Russelliana solanicola Tuthill, 1959) from Malva nicaeensis L. was identified as a potential vector of ‘Candidatus Phytoplasma pruni’. Over an 8-month period, 2089 specimens of a species of Psylloidea, including immatures and adults, were captured. We only selected the adults used for transmission trials in Catharanthus roseus (L.) G. Don (periwinkle) plants. By nested PCR, using primer pairs for phytoplasma detection in 16S rRNA and IdpA genes, 7 out of 113 (6.2%) periwinkle plants used in transmission trials were found to be infected by phytoplasmas. Insects that fed on these plants also tested positive for the same phytoplasmas. Periwinkle plants never showed virescence and phyllody, as commonly occurs with phytoplasma 16SrIII-J infection due to the effector SAP54. In this case, using primer pairs for the SAP54 gene, an amplification product was never obtained. Virtual restriction fragment length polymorphism (RFLP) analysis of F2nR2 fragments indicated that the phytoplasma, found in both periwinkle plants and insects used in transmission trials, belongs to the 16SrIII-J ribosomal subgroup. The COI gene of the psyllids samples was amplified and sequenced, showing a similarity ranging from 84.84% to 85.02% with R. solanicola from Solanum tuberosum L. The mitochondrial genome of the psyllid was also sequenced, revealing a 14,835 bp circular DNA molecule with 37 genes. The mallow psyllid transmitted the phytoplasma 16SrIII-J to periwinkle plants. The molecular identification of the insect does not match the morphological one, indicating that the mallow psyllid may constitute a cryptic species within the polyphagous R. solanicola species. This is the first report of a psyllid as a vector of the phytoplasma 16SrIII-J. Full article

Background/Objectives: Ischemic stroke remains a leading cause of death and disability worldwide. Despite significant progress in reperfusion therapy, the optimal ischemic stroke management strategy has not been developed. Recent studies demonstrate that microRNA may play an essential role in the pathophysiology of ischemic stroke and its possible potential to be a treatment target point. The proposed systematic review aimed to report the relationship between IS’s clinical severity and miRNA expression. Secondary outcomes included infarct volume, systemic inflammatory markers, and prognosis, as well as additional features such as stroke subtype, comorbidity, and risk of subsequent stroke in correlation to miRNA expression. Methods: We have performed a systematic search of database resources according to PRISMA statement guidelines. Twenty-seven studies on a total number of 3906 patients were assessed as suitable for the present SR. Included studies analyzed the expression of 30 different miRNA fragments. Results: After investigating available data, we have identified a set of possible miRNA fragment candidates that may be used in stroke diagnostics and have the potential to be a base for the development of future treatment protocols. Conclusions: Studies included in the presented SR indicate that miRNA expression may be significantly associated with clinical severity, infarct volume, and inflammation in ischemic stroke. More prospective, properly designed protocols with consistent methods of miRNA testing and optimized clinical assessment are needed to confirm the role of miRNA expression in the course of a stroke. Full article

Antibiotic resistance in Helicobacter pylori is increasing rapidly and emerging as a major factor in treatment failure. We aimed to identify genetic mutations associated with resistance to clarithromycin (23S rRNA peptidyl transferase), fluoroquinolones (gyrA), and metronidazole (rdxA), and to explore their mechanisms of action through molecular modeling. H. pylori detection and the molecular characterization of genes were conducted directly on gastric biopsies by real-time PCR followed by nucleotide sequencing. A 3D model was used to evaluate molecular interactions between the antibiotics and respective target proteins. H. pylori was identified in 66.7% of 33 patients. An analysis of 23SrRNA revealed novel mutations that, by in silico analysis, do not appear to contribute to clarithromycin resistance. In gyrA, mutations in amino acid residues 87 and 91 had an incidence of 27%, and the in silico analysis revealed that these positions are relevant in the binding and resistance to fluoroquinolones. It is also reported for other mutations, some of which are never described. All rdxA mutations were missense, with R16H, M56V, H97T, G98S, A118T, V123T, and R131K predicted by in silico analysis to impact metronidazole resistance. Monitoring H. pylori gene mutations is crucial for tailoring effective antibiotic therapies. Our study advances personalized medicine by introducing novel methods to detect resistance-related mutations and uncovering the molecular mechanisms driving this resistance. Full article

Persimmon (Diospyros kaki) plants showing yellowing, reddening, die-back, and decline symptoms were observed in Mehriz (Yazd province), Iran. Total DNAs, extracted from samples collected from symptomatic and symptomless plants, were subjected to direct and nested PCR, amplifying the 16S rRNA gene of phytoplasmas using specific primer pairs. PCR amplicons of expected lengths were obtained, mainly from nested PCR, and only from samples collected from symptomatic plants. Real and virtual RFLP, phylogenetic, and DNA identity analyses of the partial 16S rRNA gene sequences suggested the presence of diverse phytoplasmas in the analyzed samples. The identified phytoplasmas were referable to ‘Candidatus Phytoplasma omanense’ (16SrXXIX group) and ‘Ca. P. australasiae = australasiaticum’ (16SrII-D subgroup). The results of the sampling and testing highlight the urgent need for an accurate survey to verify the presence and identity of phytoplasmas in symptomatic fruit trees in Iran, in order to be able to plan appropriate management strategies. Further investigations of the possible role of ‘Ca. P. omanense’ strains as an emerging threat to fruit orchards in Iran should also be performed. Full article

Traffic-related air pollution (TRAP) remains a concern for public health. However, the exact mechanisms through which TRAP affects the respiratory system are still not fully understood. This study aimed to investigate the nasal microbiome change in healthy adults after short-term exposure to TRAP, contributing to the understanding of the adverse health effects associated with TRAP. A randomized crossover controlled trial was conducted from 9 March to 30 March 2024 among college students aged 19–24 years. Twenty healthy students were recruited through a baseline questionnaire survey and randomly assigned into two groups. One group followed a crowed-testing procedure: the park portion, a three-week washout period, and then the road portion, while the other group experienced the opposite procedure. Both groups were fully exposed to either a park environment or a road environment with high traffic volume. Nasal mucus samples were collected from the participants at the end of the trial, and then 16SrRNA sequencing was performed to analyze the differences in compositional structure and diversity of the nasal microbiome when volunteers were exposed to different levels of TRAP. The α-diversity indices, including the Chao1 index (p = 0.0097), observed species index (p = 0.0089), and Faith’s PD index (p = 0.0255), demonstrated a significant increase in the nasal microbiome of healthy adults following short-term exposure to TRAP. Visualization through a two-dimensional NMDS plot (stress value < 0.2) indicated that nasal bacterial species distribution became richer after TRAP exposure. Furthermore, the relative abundance of nasal Firmicutes (Bacillota), Bacteroidota, and Actinobacteriota phyla, especially Firmicutes phylum, exhibited a richer distribution after conducting the trial in the road environment with high levels of TRAP, which was shown in the significance test of signature species. Collectively, our study indicates that short-term exposure to TRAP can affect the composition of the nasal microbiota in healthy adults. These findings offer a scientific basis for understanding how TRAP causes respiratory diseases. Full article

Chinese herbal medicines have become a new green feed additive in the aquaculture industry. The aim of this study is to investigate the effects of traditional Chinese herbal medicines (Isatidis radix, Forsythia suspensa, and Schisandra chinensis) on the growth performance, antioxidant capacity, and intestinal microbiota of hybrid snakehead (Channa maculata ♀ × Channa argus ♂). A total of 600 fish (mean weight: 15.85 ± 0.15 g) were randomly assigned to five groups, including the control group (CG), I. radix extract group (IRE), F. suspensa extract group (FSE), S. chinensis extract group (SCE), and the Chinese herbal medicine mixture group (CHMM; a mixture of extracts of I. radix, F. suspensa, and S. chinensis at the ratio of 1:1:1) for 6 weeks. The results show that the IRE-supplemented diet improved the survival rate (SR), feed efficiency ratio (FE), and condition factor (CF) compared to others. Compared to the control group, the activity of superoxide dismutase (SOD) in plasma and intestine was significantly increased in the FSE and CHMM groups, whereas the content of malondialdehyde (MDA) in plasma and liver was significantly reduced in the SCE group. A 16s rRNA analysis indicates that dietary supplementation with FSE significantly promoted the proliferation of Fusobacteriota, while IRE supplementation increased the alpha diversity of intestinal bacteria. In conclusion, the addition of I. radix to the diet of hybrid snakehead improves growth, antioxidant capacity, and liver and intestine health, and modulates the intestinal microbiota of snakehead positively. Full article

Background: Inorganic nitrate is abundant in leafy green vegetables and has been shown to exert positive cardiovascular effects through nitric oxide-related pathways. The enteral microbiome is an emerging key player in cardiovascular diseases and depends on dietary habits. Whether dietary inorganic nitrate impacts on the microbiome and atherosclerosis-associated microbiome-dependent metabolites like short chain fatty acids (SCFA) and trimethylamine N-oxide (TMAO) is unknown. Methods: In a double-blind randomized controlled trial, 30 healthy volunteers were included who either received dietary nitrate (0.12 mmol/kg bodyweight) or placebo (equimolar amounts of sodium chloride) for 30 days. The microbiome metabolites TMAO and SCFA were analyzed. The enteral microbiome was analyzed by 16S-rRNA sequencing at baseline and follow-up. Results: Systolic blood pressure decreased after nitrate supplementation (baseline 124.73 mmHg vs. follow up 120 mmHg, p < 0.05) with no change in controls. Dietary nitrate supplementation increased TMAO levels (nitrate baseline 349.28 μ/L vs. nitrate follow-up 481.15 μ/L, p < 0.05), while SCFA levels remained unchanged. The relative abundance of Akkermansia and taxa of Clostridiales were higher in individuals with high compared to normal TMAO levels after nitrate supplementation, while Shannon diversity, richness and evenness did not differ between both groups. Conclusions: Our results indicate that dietary nitrate supplementation is associated with alterations to the enteral microbiome with an impact on proatherogenic metabolites. Further work is warranted to investigate the causal relationship between dietary nutrients, the microbiome and downstream metabolites. Full article

Background/Objectives: Metabolic diseases in humans, such as obesity or type 2 diabetes, arise from defects in the body’s ability to take in and store nutrients such as carbohydrates and triglycerides. Previous studies in the fruit fly, Drosophila melanogaster, have identified SR proteins, mRNA splicing factors that regulate splice-site selection, as regulating lipid storage in the fly fat body. However, whether SR proteins function in other tissues to regulate nutrient metabolism is not known. Methods: We focused on studying the role of SR proteins in intestines by decreasing their levels in the fly gut and measuring the concentrations of lipids and glycogen. Results: We further characterized the intestinal functions of 9G8, an SR protein, which displayed an increase in organismal lipid levels when knocked down in the intestine but had less triglyceride storage in isolated intestines. Interestingly, decreasing 9G8 in the intestine resulted in increased intestinal expression of five fatty acid synthesis/elongation enzyme genes, as well as four triglyceride lipase genes, which may contribute to the triglyceride phenotypes we observed in 9G8-RNAi flies. Conclusions: These data suggest that 9G8 regulates whole body and intestinal lipid homeostasis by altering the expression of lipid metabolic enzyme genes in the fly intestine. Full article