Microbiology Research Journal International

Effects of Atrazine and Dichlorvos on Soil Microbial Biomass and Snail Toxicity: A Microcosm Study

Tega Lee-Ann ATAIKIRU, Albert Chukwuemeka IBEZUTE — Fri, 29 May 2026 00:00:00 +0000

Agricultural pesticides like Atrazine and Dichlorvos persist in soil; disrupt microbial communities and soil-dwelling organisms such as snails, affecting key ecosystem processes. These chemicals reduce microbial biomass indicators (MB-C, MB-N, MB-P) and biodiversity, highlighting the need for integrated studies on their combined ecological impacts in soil systems. This study investigated the effects of Atrazine and Dichlorvos on microbial biomass carbon (MB-C), nitrogen (MB-N), phosphorus (MB-P), soil microbial populations, and snail toxicity in a controlled microcosm. Surface soils (0–15 cm) from pesticide-free plots at the Federal University of Petroleum Resources, Effurun, Nigeria, were characterized and treated with manufacturer-recommended doses of both pesticides for 8 weeks. Contaminated and uncontaminated soils were assessed weekly for MB-C, MB-N, MB-P, and microbial population changes using aerobic plate counts. Also, the acute effect of both pesticides on snails was assessed using a 14 day soil bioassay following standard protocol. The pristine soil was moderately acidic (pH 6.70), with a total organic carbon, total nitrogen, phosphate and nitrate contents of 3.316%, 0.3029%, 26.32 mg/kg and 36.28 mg/kg, respectively. Baseline microbial counts were 6.30 × 10⁷ CFU/g for bacteria and 1.41 × 10⁵ CFU/g for fungi. Both pesticides caused initial reductions in MB-C, MB-N, and MB-P, followed by recovery by day 28, when MB-C (293 µg/g), MB-N (18.5 µg/g), and MB-P (11.4 µg/g) exceeded control values. Phosphate-solubilizing bacteria and actinomycetes declined notably. Acute toxicity tests using Helix aspersa showed Dichlorvos to be far more toxic (LC₅₀: 1.13 mg/kg) than Atrazine (LC₅₀: 10.04 mg/kg). This study demonstrated distinct pesticide impacts on soil microbial functioning and non-target invertebrates.

Assessing the Differential Effects of Bovine Lactoferrin on the Growth of Various Bacterial Species

Jacinth C. Tran, Brian Alfaro — Fri, 29 May 2026 00:00:00 +0000

Background: Lactoferrin is an iron-binding glycoprotein found in secretions like milk, saliva, and tears that plays a key role in innate immunity. It inhibits bacterial growth by sequestering iron and also helps modulate immune responses, making the environment less favorable for microbes.

Aims: This study aimed to evaluate the effects of bovine lactoferrin on bacterial growth and determine whether the effect varies among species.

Study Design: A factorial experimental laboratory study was conducted using a comparative growth assay, employing agar media plates treated with three varying concentrations of lactoferrin alongside a control group

Place and Duration of Study: The study was performed at the Department of Biology at Eastern University over a single academic semester.

Methodology: Four bacterial species (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and S. epidermidis) were cultured on nutrient agar media. Plates were supplemented with increasing concentrations of bovine lactoferrin, and colony diameter was used as a proxy for bacterial growth. Measurements were compared across treatments and control to evaluate differential responses.

Results: Bovine lactoferrin significantly affected bacterial colony diameter (P < .001), with colony growth generally reduced in lactoferrin-treated media compared to controls. Colony size also differed significantly among bacterial species, with the largest colonies observed in P. aeruginosa and E. coli, followed by S. aureus and S. epidermidis, and a significant treatment × species interaction (P < .001) indicated species-specific responses to lactoferrin exposure.

Conclusion: It is concluded that bovine lactoferrin treatment inhibited bacterial growth in a concentration-dependent manner, though effectiveness is species-specific. These findings suggest that antimicrobial properties of lactoferrin may be context-dependent, with variation in susceptibility likely influenced by intrinsic bacterial characteristics, necessitating further research into the underlying mechanisms.

Sentinel surveillance of the WHO-Validated Pfkelch13 C580Y Artemisinin Resistance Marker in Plasmodium falciparum Isolates from Bangui, Central African Republic

Fri, 29 May 2026 00:00:00 +0000

Background: Artemisinin-based combination therapies (ACTs) are the cornerstone of malaria treatment. However, partial artemisinin resistance associated with mutations in the Plasmodium falciparum Pfkelch13 propeller domain threatens malaria control efforts. The C580Y substitution is the principal World Health Organization (WHO) validated molecular marker for resistance surveillance. While validated Pfkelch13 mutations have recently emerged in East Africa, data from Central Africa remain scarce. This study assessed the prevalence of the C580Y mutation in P. falciparum isolates collected in Bangui, Central African Republic (CAR), in 2025.

Methods: A cross-sectional molecular surveillance study was conducted in November 2025 in Bangui. Blood samples from 399 microscopy-confirmed malaria patients were collected as dried blood spots. Parasite DNA was extracted using the Chelex-100 method. Species identification was performed by nested PCR targeting the 18S rRNA gene. P. falciparum-positive samples underwent nested PCR amplification of the pfk13 propeller domain, followed by PCR–restriction fragment length polymorphism (PCR-RFLP) to detect the C580Y mutation. Exact 95% binomial confidence intervals were calculated.

Results: Among 399 patients (mean age 27.8 ± 11.9 years; 52.6% male), 99.75% harbored P. falciparum. Successful Pfkelch13 amplification was achieved in 368 of 398 isolates (92.5%). No C580Y mutation was detected (0/368; 0%; 95% CI: 0.00–0.81%), indicating that its prevalence in Bangui is likely below 1%.

Conclusion: The absence of the WHO-validated C580Y marker in 2025 suggests preserved molecular susceptibility of Plasmodium falciparum to artemisinin in CAR. Continued genomic surveillance remains essential to detect potential emergence or importation of resistant lineages.

Current Status and Case Studies on the Role of Endophytes in Insect Pest Management: A Review

Mon, 01 Jun 2026 00:00:00 +0000

Endophytes, comprising diverse groups of bacteria and fungi that reside asymptomatically within plant tissues, have emerged as promising biological agents in sustainable insect pest management. These microorganisms establish mutualistic associations with host plants and confer protection against insect pests through multiple direct and indirect mechanisms. Recent advances in microbial ecology, molecular biology and biotechnology have significantly improved our understanding of endophyte-mediated resistance. Endophytic fungi, particularly entomopathogenic species, play a dual role by colonizing plant tissues and simultaneously acting against herbivorous insects. Their ability to produce bioactive secondary metabolites, induce systemic resistance and enhance plant fitness makes them a viable alternative to synthetic pesticides. Numerous laboratory and field-based case studies have demonstrated their efficacy against a wide range of insect pests including aphids, borers, caterpillars and beetles. However, challenges such as inconsistent colonization, environmental variability, and limited commercialization still hinder their large-scale application. This review highlights the current status, mechanisms, and case studies of endophytes in insect pest management, emphasizing their potential integration into modern Integrated Pest Management (IPM) strategies.