Iranian Journal of Microbiology

Lacticaseibacillus casei and Lacticaseibacillus rhamnosus cell-free supernatants induce apoptosis-related responses in PANC-1 human pancreatic cancer cells

Sun, 07 Jun 2026 00:20:53 +0430

Background and Objectives: This study aimed to evaluate the anticancer potential of Lacticaseibacillus casei and Lacticaseibacillus rhamnosus cell-free supernatants (CFSs) against the PANC-1 human pancreatic cancer cell line, focusing on apoptosis, cell cycle modulation, and the expression of BAX and BCL-XL genes.
Materials and Methods: PANC-1 cancer cells and adult human dermal fibroblast (HDFa) cells were treated with various concentrations of individual or combined CFSs. Cell viability was assessed using the MTT assay. Apoptosis was evaluated through Hoechst/PI staining and flow cytometry, while cell cycle distribution was analyzed via flow cytometry. Gene expression of BAX and BCL-XL was measured by quantitative real-time PCR.
Results: At 20% (v/v), all CFS treatments significantly reduced PANC-1 cell viability while showing minimal effects on HDFa cells. Flow cytometry confirmed apoptotic rates of 39.33%, 42%, and 40.33% for L. casei, L. rhamnosus, and their combination, respectively, alongside a notable increase in S-phase cell population. Gene expression analysis showed a pro-apoptotic shift, characterized by BAX upregulation and BCL-XL downregulation.
Conclusion: CFSs from L. casei and L. rhamnosus showed anticancer effects on PANC-1 cells, inducing apoptosis, S-phase arrest, and a favorable shift in apoptosis-related gene expression. These findings highlight their potential as promising adjuvant candidates for pancreatic cancer therapy.

Helicobacter pylori infection and the hypothalamic–pituitary axis: association with cortisol and thyroid-stimulating hormone levels in adults

Sun, 07 Jun 2026 00:25:07 +0430

Background and Objectives: Helicobacter pylori is a common chronic bacterial infection primarily associated with gastrointestinal disease. Increasing evidence suggests that H. pylori may also exert systemic effects beyond the stomach, including possible modulation of neuroendocrine pathways. This study aimed to investigate the association between H. pylori infection and alterations in serum cortisol and thyroid-stimulating hormone (TSH) levels as indicators of hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-thyroid (HPT) axis activity.
Materials and Methods: In this case-control study, 850 adults were enrolled, including 425 H. pylori-positive cases and 425 H. pylori-negative controls. Active H. pylori infection was determined using a monoclonal stool antigen test (HpSA). Fasting venous blood samples were collected between 08:00 and 10:00 AM under standardized conditions. Serum cortisol and TSH levels were measured using validated immunoassays. Group comparisons, correlation analysis, sex-stratified subgroup analysis, and receiver operating characteristic (ROC) curve analysis were performed.
Results: H. pylori-positive participants had significantly higher serum cortisol levels and lower TSH levels compared with controls (both p < 0.001). A significant inverse correlation between cortisol and TSH was observed only in infected participants (r = -0.41, p < 0.001). These hormonal alterations were evident in both sexes. ROC analysis showed moderate discriminatory performance for cortisol (AUC = 0.71) and fair-to-moderate performance for TSH (AUC = 0.67).
Conclusion: H. pylori infection was significantly associated with elevated cortisol levels, reduced TSH levels, and an inverse relationship between both hormones in adults. These findings suggest that chronic H. pylori infection may influence both HPA and HPT axis regulation and support further investigation into its systemic neuroendocrine effects.

Multiplex qPCR for the early detection of sepsis pathogens and its impact on antimicrobial therapy in critically ill patients

Sun, 07 Jun 2026 00:27:53 +0430

Background and Objectives: Sepsis is a life threatening condition caused by a dysregulated host response to infection and is associated with high morbidity and mortality worldwide. Early bacterial detection and therapy with antibiotics improve outcomes. We compared multiplex quantitative PCR (qPCR) to traditional blood culture for early pathogen detection in critically ill patients with suspected sepsis.
Materials and Methods: This prospective observational study included 200 critically ill ICU patients with suspected sepsis. Multiplex qPCR using the TRUPCR® Sepsis Panel was compared with conventional blood culture for pathogen detection. To assess sensitivity, specificity, PPV, and NPV, blood culture was used as the reference standard. Mortality, ICU stay, and antibiotic therapy time were studied. Multivariable logistic regression was adjusted for baseline severity (SOFA, APACHE II), septic shock, and antibiotic exposure.
Results: Multiplex qPCR significantly reduced the time to initiation of appropriate antibiotic therapy (5.2 vs 8.3 hours, p<0.001). The assay demonstrated higher sensitivity compared with blood culture for pathogen detection. qPCR positivity was associated with shorter ICU stay and lower mortality; however, these associations were interpreted after adjustment for baseline illness severity. Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus were the most frequently detected pathogens, and several antimicrobial resistance genes including bla_CTX-M, bla_NDM, and mecA were identified.
Conclusion: Multiplex qPCR can detect infections early and optimize antimicrobials for sepsis. These findings should be cautiously evaluated and corroborated in larger multicentre trials due to reduced specificity and observational nature.

Moleculartyping and antibiotic resistance pattern of Aeromonas hydrophila isolated from children with diarrhea in Qom, Iran

Sun, 07 Jun 2026 00:30:27 +0430

Background and Objectives: Today there are reports of the spread of multiple antibiotic resistance in Aeromonas spp., which can be opportunistic pathogens and can cause infection in the host. This study aimed to investigate ERIC-PCR and BOX-PCR typing, drug resistance pattern, and tetracycline, sulfonamide, and fluoroquinolone resistance genes in Aeromonas hydrophila collected from diarrhea samples of children in Qom City, Iran.
Materials and Methods: In our cross-sectional descriptive study, isolates of A. hydrophila isolated from children's diarrhea samples at Hazrat Masoumeh Hospital in Qom were evaluated between 2018 and 2020. Once isolates confirmed, the level of antimicrobial resistance of the strains was determined by the disk diffusion assay following the recommendations of Clinical and Laboratory Standards Institute (CLSI). The genes of tetA, tetB, tetC, tetD, tetE, sul1, sul2, Edq1qc, qnrA, qnrB, qnrS were studied using the PCR method. Then the genetic diversity of the isolates was investigated by ERIC-PCR and box-PCR. Finally, data analysis was done with SPSS version 16.
Results: From 100 A. hydrophila strains, the highest resistance, and sensitivity were related to ampicillin (92%) and azithromycin (96%), respectively. The frequency of tetA, tetB, tetC, tetD, tetE, sul1, sul2, Edq1qc, qnrA, qnrB, qnrS genes was 23, 24, 27, 23, 21, 26, 10, 22, 8, 11, 15%, respectively. With ERIC-PCR and BOX-PCR techniques, all isolates could be typed, so that 8 genetic patterns were determined in ERIC-PCR and 10 genetic patterns were determined in BOX-PCR. A significant relationship was found between cefotaxime and tetA (p = 0.012), ciprofloxacin and tetC (p = 0.018), cefotaxime and qnrA (p = 0.04), and also between tetracycline resistance genes and both sulfonamide genes (p > 0.05).
Conclusion: For the first time this study revealed resistance genes for tetracycline, sulfonamide, and fluoroquinolones in A. hydrophila isolated from childeren’s diarrhea samples in Qom. Even though these antimicrobial resistance genes are present in our study and bacteria are resistant to different types of antimicrobials, it can be predicted that the abundance of these genes will increase in the future. We also observed that A. hydrophila isolates had high genetic diversity.

Evaluation of susceptibility to colistin, fosfomycin and mecillinam in carbapenemase-producing Enterobacterales isolated in Marrakech in 2023

Sun, 07 Jun 2026 00:33:37 +0430

Background and Objectives: Carbapenemase-producing Enterobacterales (CPE) constitute a critical public health concern due to multidrug resistance and limited available treatment options. This study aimed to assess the in vitro susceptibility of CPE isolates to colistin, fosfomycin, and mecillinam.
Materials and Methods: Prospective study was conducted in 2023 at Mohammed VI University Hospital, Marrakech. A total sample of 180 non-duplicate CPE isolates were collected and identified by standard microbiological methods. Antimicrobial susceptibility testing was performed following recommended guidelines.
Results: Among the isolates, Klebsiella pneumoniae (60%) and Escherichia coli (14%) predominated. The most common carbapenemase was NDM (62%), followed by OXA-48 (26%) and co-producers (11%). Most isolates were obtained from intensive care (32%), plastic surgery (13%), and neonatology (12%) units. Skin and soft tissue (43%) and bloodstream (21%) were the predominant infected sites. Resistance rates were 25% for colistin, 48% for fosfomycin, and 64% for mecillinam, with frequent co-resistance to fluoroquinolones, aminoglycosides, and cotrimoxazole.
Conclusion: The high prevalence of NDM-producing Klebsiella pneumoniae and significant resistance to last-line agents suggest the urgent need for antimicrobial stewardship, optimized therapeutic strategies, and strengthened regional surveillance.

Efficacy of a bacteriophage cocktail in controlling Salmonella Enteritidis infection in broiler chickens

Sun, 07 Jun 2026 00:37:50 +0430

Background and Objectives: Salmonella Enteritidis is widespread in the world and is known to be among the most common agents of zoonotic food-borne illnesses. This study evaluates the efficacy of a bacteriophage cocktail — comprising SEPL01 (Siphovirus) and SEPL13 and SEPL20 (Myoviruses) — in controlling Salmonella Enteritidis infection in poultry.
Materials and Methods: A total of 168 one-day-old desi chicks were procured and randomly divided into five different groups: negative control, positive control, prophylactic, 6 h and delayed post-challenge treatment group. Birds in the positive control and trial groups were orally infected with 10⁵ CFU/ml S. Enteritidis on the fourth day. The bacteriophage was given in 10⁷ PFU/ml through oral gavage, drinkers and aerosol spray. Bacterial enumeration was done using dilution plate counting on XLD agar and bacterial reduction was determined using log10 reduction.
Results: Among the groups, the prophylactic group showed the highest log₁₀ bacterial reduction: 1.92 (Day 3), 1.79 (Day 7), and 1.23 (Day 14). Drinking water administration resulted in a log₁₀ reduction of 1.62, 1.44, and 0.91, respectively, while aerosol spray was the least effective with a log₁₀ reduction of 1.12, 0.85, and 0.52 across the same days. The treatment group receiving therapy 6 hours post-challenge exhibited a moderate level of reduction: 1.63, 1.37, and 1.22 via oral gavage; 1.43, 1.15, and 0.94 via drinkers; and 0.46, 0.15, and 0.12 via aerosol spray. The delayed post-challenge group showed smaller reductions: 1.56, 1.24, and 0.92 by oral gavage; 1.25, 0.99, and 0.79 by water; and 0.42, 0.13, and 0.10 by aerosol spray.
Conclusion: The bacteriophage therapy is highly effective in reducing Salmonella Enteritidis, demonstrating potential as an antibiotic alternative.

Antimicrobial and antioxidant properties of green synthesis CuO nanoparticles using Salvia officinalis hydroalcoholic extract

Sun, 07 Jun 2026 00:44:15 +0430

Background and Objectives: Following the emergence of microbial resistance to chemical antimicrobial agents, researchers have recently focused on the effects of nanoparticles and their antimicrobial activity. This research aimed to investigate the antimicrobial and antioxidant activity of copper oxide nanoparticles (CuO-NPs) produced using the hydroalcoholic extract of Salvia officinalis (S. officinalis).
Materials and Methods: In this study, after preparing the hydroalcoholic extract of S. officinalis and synthesizing CuO-NPs using this extract, the synthesized nanoparticles were evaluated. The antimicrobial properties of synthesized CuO-NPs were investigated by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the microbroth dilution method. The minimum biofilm inhibitory concentration (MBIC) and antioxidant activity of CuO-NPs and the hydroalcoholic extract of S. officinalis against Pseudomonas aeruginosa (P. aeruginosa) were investigated.
Results: CuO-NPs have a size in the range of 40 nm and a monoclinic crystal structure. Antimicrobial activity assessment by well diffusion showed that the synthesized CuO-NP nanoparticles at concentrations below 5 mg/mL had no antimicrobial effect on any of the bacteria studied. The lowest MIC of the synthesized CuO-NPs was observed against Staphylococcus saprophyticus (S. saprophyticus), and the highest against P. aeruginosa and Bacillus cereus (B. cereus). On the other hand, the highest MBC was related to B. cereus. The plant extract exhibited much weaker antimicrobial activity than CuO-NPs. The results obtained showed that the MBIC for CuO-NPs was 312 μg/mL. The half-maximal inhibitory concentration (IC₅₀) obtained from CuO-NPs and the hydroalcoholic extract of S. officinalis was 2.79 and 1.97mg/ml, respectively.
Conclusion: Based on the results of this study, the green synthesis of CuO-NPs using hydroalcoholic extract of S. officinalis is a suitable candidate for the preparation of antimicrobial and antibiofilm compounds that also have antioxidant properties.

Genetic variations on influenza virus infection outcomes in Moroccan patients

Sun, 07 Jun 2026 00:46:25 +0430

Background and Objectives: The influenza infection remains a significant global health challenge, it leads to illnesses that vary from mild to severe, and in certain cases, death. The innate immune response is the first line of defense against pathogen invaders; identification of variants associated with susceptibility or protection could further elucidate immune mechanisms and provide the basis for new therapeutic targets.
Materials and Methods: We investigated four widely studied SNPs on the immune response to RNA infection in samples collected as part of sentinel influenza surveillance system. Of 1925 nasopharyngeal swabs collected from patients with Severe Acute Respiratory Infection (SARI) and Influenza-Like Illness (ILI), 115 samples were positive for ILI and 83 were positive for SARI. A third group of healthy individuals was also enrolled as a control. Genetic polymorphisms of the OAS3 (rs10735079), TYK2 (rs74956615) and APOBEC3G (rs8177832 and rs2294367) genes were genotyped using Human TaqMan SNP Genotyping Assays (ThermoFisher Scientific©). The association of Single Nucleotide Polymorphisms (SNPs) with ILI and SARI was investigated using SNPStats software.
Results: The rs2294367 in APOBECG3 show a strong and significant association with ILI and SARI across all genetic models, with a p-value<0.001 and OR between 2 and 6, while no association was found with rs8177832. The results for TYK2 suggest a potential protective effect, while the OAS3 SNP shows a strong and significant association with a decreased risk of Influenza infection specially with ILI group (OR<1 and p < 0.0001).
Conclusion: Our results open up a new perspective for new methods and strategies of therapy aimed to enhance the body's natural defenses against influenza virus infection.

Epidemiology and subtype analysis of respiratory syncytial virus among hospitalized children under five in Isfahan during early 2024

Forough Tavakoli, Sharareh Moghim, Vahid Salimi, Mohammad Ali Pourmirzaiee — Sun, 07 Jun 2026 00:49:44 +0430

Background and Objectives: Respiratory syncytial virus is the most common virus causing acute respiratory infections in children under 5 years old. We aimed to investigate the prevalence and circulating strains of RSV in hospitalized children in Isfahan.
Materials and Methods: Between January and May 2024, children under 5 years of age were enrolled in this study. Nasal swabs were collected from 100 children with acute respiratory infections admitted to the referral pediatric ward at Imam Hossein Children’s Hospital in Isfahan, Iran. The prevalence of circulating RSV was investigated using the RSV qPCR detection kit. The virus type was identified by RT-PCR using type A- and B-specific primers.
Results: A total of 51 (51%) samples tested positive for RSV. Among them, typing was done in 33 specimens, of which 66.6% (22/33 cases) were assigned as subtype B and 33.3% (11/33 cases) as subtype A. Infants under 6 months were most severely affected by RSV (47.1%, 24/51). RSV-positive samples peaked in February (43.1%), followed by January (29.4%).
Conclusion: The results of the current study revealed a high prevalence of RSV and co-circulation of subtypes A and B, with subtype B more prevalent among children. This highlights the importance of ongoing surveillance of RSV.

Rotavirus-associated acute gastroenteritis in children under five years: a cross-sectional study from southern Iran

Sun, 07 Jun 2026 00:51:47 +0430

Background and Objectives: Rotavirus is a major cause of acute gastroenteritis in children. This study assessed the frequency and clinical characteristics of rotavirus infection in children under five years old.
Materials and Methods: This cross-sectional study was conducted in 2020 on children with acute gastroenteritis. Clinical and demographic data were collected, dehydration severity was assessed by a pediatrician, and stool samples obtained within 48 hours of admission were tested for rotavirus antigen using ELISA.
Results: A total of 301 children with acute gastroenteritis were included. Rotavirus antigen was detected in 34.6% of cases. Vomiting (81.2%) and diarrhea (96.1%) were significantly common among rotavirus-positive children (p = 0.01). Severe dehydration (>10%) and the need for parenteral rehydration were observed more frequently among rotavirus-positive children compared with rotavirus-negative cases (20.9% vs. 9.2%, p = 0.02 and 91.1% vs. 78.1%, p = 0.01, respectively). However, these findings should be interpreted cautiously, as clinical severity may also have been influenced by other demographic and clinical factors.
Conclusion: Rotavirus was detected in a considerable proportion of children with acute gastroenteritis in southern Iran. Rotavirus-positive cases showed more frequent severe dehydration, although this finding should be interpreted cautiously. Early assessment and supportive care remain important.

High prevalence of seronegative occult hepatitis C in high-risk individuals

Sun, 07 Jun 2026 00:54:28 +0430

Background and Objectives: Routine screening for occult hepatitis C virus (OHCV) is not a standard procedure in medical laboratories, which has resulted in an increased incidence of OHCV among high-risk groups and the general population. The objective of this study was to investigate the molecular epidemiology of (OHCV) in Iranian injecting drug users (IDUs).
Materials and Methods: To determine chronic hepatitis C virus(HCV) and OHCV, plasma and peripheral blood mononuclear cell (PBMC) were collected from 103 (96 (93.2%) males, 7 (6.79%) females) IDUs. Their plasma was tested for Anti-HCV (ELISA). Following RNA extraction from plasma and PBMCs, RT-nested PCR was employed to amplify the 5′ untranslated region (5′UTR) and core regions of the HCV genome in plasma and PBMCs from IDUs. Sequencing of the 5′UTR and core regions, along with phylogenetic tree construction, was used to determine HCV genotypes.
Results: Among the 103 individuals, 12/96 males (12.5%) were positive for both anti-HCV and HCV RNA in plasma, indicating chronic HCV infection. In addition, 18/96 males (18.75%) and 1/7 females (14.28%) were positive for anti-HCV but negative for HCV RNA, indicating evidence of past HCV infection (p = 0.1). Furthermore, 5 individuals, including 4/94 males (4.1%) and 1/7 females (14.28%), were found to be seropositive for HCV (p = 0.77). Meanwhile, 23/103 individuals (22.33%), including 20/96 males (20.8%) and 3/7 females (42.85%), were seronegative for HCV (p = 0.37). HCV genotype 1a was the dominant genotype among IDUs.
Conclusion: In conclusion, a high prevalence of HCV infection was observed among IDUs, underscoring the pressing necessity for the implementation of an efficacious strategy to eradicate HCV transmission in this high-risk population.

Molecular detection of Anaplasma spp. in blood and ticks collected from sheep and goat in West Azerbaijan province, Iran

Ahmad Enferadi, Amir Tukmechi, Katayoon Nofouzi, Zahraalsadat Tavakolian — Sun, 07 Jun 2026 00:56:18 +0430

Background and Objectives: Anaplasmosis, an ailment affecting both captive and free-ranging small ruminants, is instigated by Anaplasma spp., a tick-vectored, obligate intracellular rickettsial bacterium. Iran's ovine and caprine populations, numbering roughly 71 million, are vital to its financial structure.
Materials and Methods: This study investigated the prevalence of Anaplasma species in sheep and goats within West Azerbaijan province. Additionally, nucleic acid specimens were isolated from gathered ticks and examined for Anaplasma spp. Through polymerase chain reaction (PCR) utilizing the major surface protein gene (groEL).
Results: Anaplasma was detected in 161 (69.0%) of 919 ovine and 82 (71.3%) of 243 caprine blood DNA extracts. Subsequently, genetic material from 426 ticks comprised of Rhipicephalus sanguineus (n=146), Rhipicephalus turanicus (n=63), Hyalomma asiaticum (n=56), Hyalomma anatolicum (n=74), and Hyalomma egebtiom (n=87) was screened for A. ovis utilizing the same methodology.
Conclusion: This research not only confirmed the presence of A. ovis within Iranian sheep and goats but also implicated ticks as a possible vector for its transmission. The findings emphasize the importance of monitoring the health status of Iran's small ruminants to detect clinical manifestations of anaplasmosis and of implementing effective tick control strategies worldwide.

In vitro antifungal resistance and molecular analysis of the SQLE gene in dermatophytosis: a laboratory-based study

Jegan Charlies, Latha Ragunathan, Kavitha Kanniyan, Jeyakumari Duraipandian — Sun, 07 Jun 2026 00:58:14 +0430

Background and Objectives: Dermatophytosis is a common superficial fungal infection that affects the keratinised tissues. This study examines the antifungal resistance mechanisms and molecular detection of squalene epoxidase gene alterations in clinical isolates from patients.
Materials and Methods: A cross-sectional study conducted from January 2019 to December 2020 included 110 clinically suspected dermatophytosis specimens. Microscopy, culture, CLSI M38-A2 broth microdilution testing, and PCR-based ITS and SQLE (520 bp) amplification were performed. MIC50, MIC90, geometric mean, and ranges were analysed using SPSS version 19 with P < 0.05.
Results: A total of 110 suspected cases were evaluated, with 78 (70.9%) males. KOH positivity reached 100%, while culture positivity was 47.3% (52/110). Trichophyton rubrum accounted for 38.5% isolates. Fluconazole MICs were ≥64 µg/mL. 39/52 isolates showed terbinafine resistance, with 23 expressing the 520 bp SQLE gene.
Conclusion: Terbinafine and caspofungin showed consistent in vitro activity, while fluconazole showed limited activity. Routine susceptibility testing guides drug selection, improves treatment outcomes, and supports rational management of resistant dermatophytosis cases.

Spectrum of central nervous system mycoses and antifungal susceptibility: a two-year retrospective analysis from a tertiary care hospital in India

Sun, 07 Jun 2026 01:00:26 +0430

Background and Objectives: The frequency of central nervous system (CNS) fungal infections is rising, leading to increased mortality. These infections pose diagnostic challenges, and therapy depends on the specific fungal pathogen identified. Only a few studies from India have examined the spectrum of fungal pathogens causing CNS infections. The objective of this study was to analyze the clinical and microbiological diversity of fungal pathogens responsible for CNS infections.
Materials and Methods: This was a retrospective study conducted at a tertiary care center in India from January 2023 to December 2024. The study included patients in whom fungi were isolated from cerebrospinal fluid, brain abscess pus, and paraspinal abscesses.
Results: Nine fungal pathogens were identified during the study period. Three isolates were yeasts and six were molds. Brain abscess was the predominant clinical presentation. The yeast isolates included Cryptococcus neoformans (n = 1) in meningitis and Candida tropicalis (n = 1) and Candida parapsilosis (n = 1) in VP shunt infections. The molds isolated from brain abscesses included Cladophialophora bantiana (n = 1), Rhizopus arrhizus (n = 1), Aspergillus flavus (n = 2), Scedosporium apiospermum (n = 1), and Chaetomium lucknowensis (n = 1). Mortality was observed in 4 of 9 cases (44.4%).
Conclusion: In the present study, nine fungal pathogens were isolated over a two‑year period from varied clinical presentations. This highlights the rarity of the condition, which should not be overlooked.

Mating type and genotyping of Candida albicans isolated from different samples

Sun, 07 Jun 2026 01:02:37 +0430

Background and Objectives: Candida albicans is a common opportunistic pathogen. Genotyping based on the 25S rDNA and mating type locus (MTL) allows for epidemiological and genetic profiling. This study aimed to characterize the genotypes and mating types of C. albicans isolates from various clinical sources in Iran.
Materials and Methods: Ninety-four isolates from clinical samples (saliva, urine, vaginal swabs, and skin scrapings) were cultured on CHROMagar Candida and identified by standard phenotypic methods. Genotyping was performed using CA-INT primers, and mating type analysis was conducted using MTLa1 and MTLα1 primers.
Results: In this study, 94 isolates of C. albicans from various sources were analyzed. Genotype A was the most frequent (65%), followed by genotypes C (24.5%), B (9.6%), and D (1.1%). Most isolates (97.9%) were heterozygous at the MTL locus, only two isolates homozygous (α/α).
Conclusion: Genotype A and MTL-heterozygous strains were predominant among C. albicans isolates, suggesting a consistent molecular pattern across different clinical sources and regions.

Simultaneous GCN4 co-expression and promoter optimization enhance glucose oxidase production in Pichia pastoris

Sun, 07 Jun 2026 01:04:53 +0430

Background and Objectives: This study aimed to enhance glucose oxidase (GOX) production in Pichia pastoris GS115 using a novel dual-promoter system, combining the constitutive glyceraldehyde-3-phosphate dehydrogenase promoter (pGAP) in pGAPZαA with the methanol-inducible Alcohol oxidase 1 promoter (pAOX1) in PIC9.
Materials and Methods: The GOX gene from Aspergillus niger (ATCC 9029) and a transcription factor, general control nonderepressible 4 (GCN4) gene from P. pastoris were co-expressed to mitigate oxidative stress, thereby improving cell viability and enzyme yield. The recombinant construct pGAPZαA-GOX-GCN4 was transformed into P. pastoris GS115 and P. pastoris GS115-PIC9 via electroporation. Expression conditions under various temperatures and pH treatments were optimized. We examined glucose oxidase expression by inducing methanol at concentrations of 100% and 5% in BMMY (Buffered Methanol-complex-medium). The highest enzyme levels were observed at pH 6.0, 34°C, and 5% methanol induction. Enzyme validation was performed using SDS and Western blotting.
Results: Co-expression of GCN4 significantly enhanced GOX production, achieving 16.65 µg/mL (333 U/mL) in P. pastoris GS115-PIC9-pGAPZαA-GOX-GCN4(2), a 377.4-fold increase over the control, and 11.03 µg/mL (220.6 U/mL) in P. pastoris GS115-PIC9-pGAPZαA-GOX-GCN4(3), a 249.65-fold increase.
Conclusion: The results demonstrate that GCN4's stress mitigation amplifies the synergy between constitutive and inducible promoters. The dual-promoter strategy offers a robust platform for recombinant protein production.

Cellulase and β-glucosidase activity of crude enzyme extracted from fresh and expired soybean tempeh

Yenni Karlina, Defri Rizaldy, Catur Riani, Fahrauk Faramayuda, Sukrasno Sukrasno — Sun, 07 Jun 2026 01:06:44 +0430

Background and Objectives: Enzymes are protein biomolecules that act as catalysts, including cellulase and β-glucosidase with extensive applications. Thus, this work aimed to contrast the activity of both enzymes from tempeh fermented by Rhizopus microsporus at 2 and 7 days of incubation.
Materials and Methods: Incubated tempeh was tested for quality evaluation. The crude extracts of cellulase and β-glucosidase were obtained by extracting tempeh with a cold phosphate buffer solution. The presence of the R. microsporus was examined through microscopic identification, and molecular identification using PCR amplification. Cellulase activity was determined using 3.5-dinitrosalicylic acid (DNS) reagent, whereas β-glucosidase activity was evaluated by measuring the release of p-nitrophenol from p-nitrophenyl-β-D-glucopyranoside (p-NPG).
Results: The protein content and water content increase with the length of fermentation time. Microscopic identification and molecular identification confirmed the presence of R. microsporus. The highest cellulase activity was found in fresh tempeh (2-day incubation) at 0.0911 U/mL at pH 7, while the highest β-glucosidase activity was found in expired tempeh (7-day incubation) at 0.0042 U/mL at pH 5.
Conclusion: These findings indicate that the standard quality contributed to the differences in the enzymatic profile of tempeh incubated for 2 and 7 days.