Journal of Advances in Microbiology

Comparative Analysis of Diversity, Infectivity and Biting Rates of Anopheline Vectors and Their Role in Local Malaria Transmission in Afikpo-North LGA, Ebonyi State, Nigeria

V. O. Ekuma — 2026-03-06

Falciparum malaria remains a major public health burden in the rainforest region of Nigeria, where Anopheles mosquitoes serve as primary vectors. Effective malaria control requires high-quality case management, vector control, and robust surveillance. However, the emergence of drug-resistant Plasmodium falciparum strains and widespread insecticide resistance in mosquito populations threaten progress in malaria elimination. Recent advances in parasite genetics and genomics now offer new opportunities for improved surveillance. This study aimed to identify endophilic malaria vectors and assess their vectorial status and importance in two villages, Oziza–Ameta and Amachara–Elu, Afikpo-North LGA, Ebonyi State, Nigeria. Adult female mosquitoes were sampled indoors from twenty households using the pyrethrum spray catch (PSC) method. Molecular identification of Anopheles gambiae was performed using polymerase chain reaction (PCR). Natural Plasmodium infection and parasite genotypes were detected through PCR and whole-genome sequencing. Human biting rate (HBR) was estimated indirectly as the proportion of freshly fed mosquitoes relative to the number of occupants who slept in the room the night before collection. A total of 331 female mosquitoes belonging to seven species Culex quinquefasciatus, Anopheles gambiae sensu lato (s.l.), Anopheles funestus group, Mansonia uniformis, Mansonia africana, Anopheles coustani complex, and Culex poicilipes were collected. Culex quinquefasciatus was the most abundant species (61.63%), followed by An. gambiae s.l. (28.10%). Culex poicilipes and An. coustani had the lowest abundance (0.30%). Species abundance differed significantly between the two villages (p = 0.005). Malaria vector abundance was higher in Oziza–Ameta than in Amachara–Elu, with An. gambiae s.l. predominating in both locations. PCR characterization revealed An. gambiae sensu stricto (s.s.) as the dominant sibling species, with an infectivity rate of 0.035 (95% CI: 0.0059–0.1058) for Plasmodium falciparum. Genetic diversity (M-form and S-form) was detected within An. gambiae s.s., showing identity matches of 97.43% and 98.00% to AF470112.1 and AF470113.1, respectively, while the detected P. falciparum genotype matched LR131493.1 with 100% similarity. The highest human biting rates were recorded in October (40% and 50%). Endophilic female mosquitoes in Afikpo-North serve as important vectors of malaria and other diseases of public health and economic relevance, placing residents at high risk of infection. This study provides baseline information on indoor-resting malaria vectors and parasite genotypes necessary for site-specific vector control planning under Integrated Vector Management (IVM). Strengthening environmental sanitation and improving drainage systems are recommended as part of comprehensive vector control strategies.

Substituent and Scaffold Effects on the Antibacterial Activity of Ru(II) Pyridine-Imine Schiff Base Complexes

Shem Ongechi Nyang’ate — 2026-03-12

The escalating threat of antimicrobial resistance (AMR) necessitates the development of novel antibacterial agents with alternative mechanisms of action. This study reports the design, synthesis, and biological evaluation of ruthenium(II) complexes derived from pyridine-imine Schiff base ligands featuring systematic aromatic substitutions (–H, –Br, –OH) and two distinct coordination architectures: simple Ru(II) and half-sandwich Ru(II)-p-cymene. The ligands and their corresponding Ru(II) complexes were synthesized in high yields (85–92%) and characterized by melting point, FT-IR, UV-Vis, and ¹H NMR spectroscopy. Spectroscopic data confirmed bidentate N, N′-coordination through the imine and pyridyl nitrogen atoms, evidenced by shifts in C=N stretches (1625–1632 → 1600–1620 cm⁻¹), downfield movement of the imine proton (δ 7.63–7.66 → 7.43–7.55 ppm), and new metal-to-ligand charge transfer (MLCT) bands (363–575 nm). All complexes exhibited enhanced thermal stability (m.p. 175–235 °C) relative to free ligands (70–180 °C). In vitro antibacterial screening against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) via disc diffusion revealed that Ru(II) complexes consistently outperformed their parent ligands, with bromo- and hydroxy-substituted p-cymene derivatives (L-C2 and L₁-C2) showing the highest activity, zones of inhibition up to 14–15 mm at 1000 µg/mL. Statistical analysis (two-way ANOVA, p ≤ 0.05), following verification of normality (Shapiro-Wilk) and homogeneity of variance (Levene's test), confirmed significant effects of both substituent type and scaffold architecture on bioactivity. Although none surpassed gentamycin (17–21 mm), the results validate Tweedy's chelation theory and highlight Ru(II) Schiff base complexes as promising scaffolds for antimicrobial development targeting multidrug-resistant pathogens.

Influence of Trichoderma Inoculants and Organic Manure on Growth, Nodulation and Nitrogen Fixation by Soybean (Glycine max, L. Merrill) in Zinc Contaminated Soil

A. A. Soretire — 2026-03-12

Soil heavy metal contamination is a serious environmental problem that needed to be addressed due to the toxicities of metals to both humans and living organisms. soil degradation is linked to off-site issues including sedimentation, climate change, the operation of watersheds, and changes in natural ecosystems that result in a loss of genetic diversity and biodiversity. A pot experiment was conducted at the College of Plant Science- Screenhouse, Federal University of Agriculture, Abeokuta (FUNAAB), Ogun state, Nigeria, to evaluate influence of Trichoderma inoculants and organic manure on growth, nodulation and nitrogen fixation by soybean (Glycine max, L. Merrill) in zinc contaminated soil. The experiment was a 2 x 3 x 3 factorial combination arranged in completely randomized design (CRD) with three (3) replicates. Treatments were two levels of cattle dung (0 and 4.46 g kg^-1), three levels of Trichoderma at NI (No inoculation), Trichoderma asperellum, and Trichoderma harzianum (5 ml per pot) and three levels of heavy metal (zinc) at 0, 300 and 600 mg kg-¹. Five (5) kilograms of the 2 mm sieved soil was weighed into each plastic buckets and amendments was applied thereafter Trichoderma was applied at 5 ml per pot while cattle dung was applied at 4.46 gkg^-1. It was moistened to 100% field capacity and left for one week after contamination. Two seeds of soybean were planted per hole and wetting was done at 75 % field capacity when due. Number of leaves, leaf area, plant height, shoot dry weight and number of nodules were determined fortnightly. Inoculation with Trichoderma recorded higher number of nodules and percentage of N₂ fixed while zinc contamination did not significantly affect the percentage of N₂fixed. It is concluded that Trichoderma asperellum in combination with cattle dung had great potential in enhancing nodulation and nitrogen fixation by soybean in zinc contaminated soil.

Phytochemical Profiling and Acute Oral Toxicity Study of Hydro-ethanolic Extract of Whole Plant of Artemisia annua in Wistar Albino Rat

S. R. Shaikh — 2026-03-14

Aims: To evaluate the phytochemical constituents, and acute oral toxicity assessment of the hydro-ethanolic extract of the whole plant of Artemisia annua (family Asteraceae), a plant contains several pharmacologically active compounds, the most prominent being artemisinin, a hydrophobic sesquiterpene lactone responsible for its potent antiparasitic effects.

Methodology: In the present study, whole-plant material of A. annua was procured, authenticated, and processed into fine powder using a pulverizer. The powder was subjected to cold hydro-ethanolic maceration technique, and the resulting extract was evaporated and stored in airtight vials for subsequent phytochemical analyses and acute oral toxicity assessment.

Results: Hydro-ethanolic extraction yielded 6.45% crude extractability, indicating efficient recovery of phytochemicals under the extraction conditions. The extract was greenish-brown, solid and sticky, bitter in taste, and pleasant in odour, consistent with known organoleptic characteristics of A. annua extracts. Qualitative phytochemical screening of extracts prepared in twelve different solvents revealed the presence of alkaloids, flavonoids, saponins, tannins, sterols, sesquiterpene lactones, reducing sugars, glycosides, and phenolics, reflecting a broad spectrum of bioactive constituents. These compounds, particularly sesquiterpene lactones, contribute to the plant’s documented antiparasitic activity against Theileria, Babesia, Trypanosoma, Eimeria, and gastrointestinal nematodes, highlighting its importance in veterinary parasitology. Acute oral toxicity study of the hydro-ethanolic extract was assessed in Wistar albino rats following OECD guideline 420. Rats received 300, 2000, and 5000 mg/kg body weight of hydro-ethanolic extract of A. annua and were observed for 14 days. No mortality, behavioural abnormalities, or clinical signs of toxicity were observed at any dose.

Conclusion: These findings demonstrated that the hydro-ethanolic extract of A. annua is non-toxic and well-tolerated, supporting its safe use and potential as a natural antiparasitic agent in veterinary medicine.

Bacteriological Analysis of Water Stored in Tanks in and around Selected Hostels of the C. K. Tedam University of Technology and Applied Sciences (C. K. T. UTAS) in Navrongo, Ghana

Faiza Kyantima Issifu — 2026-03-19

The use of unsafe water supplies and microbial contaminated water for various domestic purposes may pose serious health challenge to users. Bacteriological analysis of water is critical for public health, as it identifies disease -causing pathogens to prevent water-borne diseases such as cholera, typhoid and dysentery. The aim of the research was to determine the bacteriological quality of water stored in tanks in and around hostels of the C. K. Tedam University of Technology and Applied Sciences (C. K. T. UTAS) in Navrongo, Ghana. Questionnaires were used to obtained information about the poly tanks and the usage of water from the tanks by students of the selected hostels. Samples of water were collected from hostels of interest and analyzed for total viable bacteria count, total coliforms and faecal coliforms using standard microbiological techniques. Samples were plated on MacConkey, Chromocult Coliform and Nutrient Agar, and isolates were subjected to Gram staining and other series of biochemical tests for identification and characterization. The outcome of the study showed the presence of Bacillus spp., Klebsiella spp., Staphylococcus spp. and Micrococcus spp., while Escherichia coli was absent in all the water samples. Total viable counts obtained were from 14cfu/mL to 147cfu/mL and total coliform counts ranges from 1cfu/mL to 3cfu/mL. These outcomes showed that water stored in hostel’s poly-tanks especially ones that have not been washed over long period of time contains bacteria species that make it unsafe for direct consumption without further treatment. The bacteriological assessment of water stored in hostel tanks within and around C. K. T. UTAS revealed that, although faecal coliforms and E. coli were absent, the presence of total coliforms and other bacteria such as Bacillus spp., Klebsiella spp., Staphylococcus spp. and Micrococcus spp. are evidence of secondary contamination that occurs due to poor storage and handling. The findings showed the need for regular cleaning and monitoring of water storage tanks to prevent waterborne diseases.

Biological Management of Cotton Target Leaf Spot (Corynespora cassiicola) Using Bacterial Endophytes

E. Rajeswari — 2026-03-23

Background: Cotton, a major global fibre and oilseed crop, is significantly affected by foliar diseases like target leaf spot, causing substantial yield losses. Due to concerns over chemical control, endophytic bacteria offer a sustainable alternative by suppressing pathogens through multiple biocontrol mechanisms.

Aims: To evaluate the efficacy of bacterial endophytes against target leaf spot of cotton under in vitro and field conditions and to identify the most effective endophyte for the eco-friendly management of the disease.

Study Design: All the laboratory experiments were conducted using a Completely Randomized Design(CRD) and field experiment was laid out using a Randomized Block Design (RBD).

Place and Duration of Study: Department of Plant Pathology and Department of Cotton, Tamil Nadu Agricultural University, Coimbatore. August 2023- December 2025.

Methodology: The target leaf spot pathogen was isolated by tissue isolation method and confirmed as Corynespora cassiicola through morphological and molecular characterization. The efficacy of bacterial endophytes against C. cassiicola was evaluated by dual culture technique. The effect of the most effective endophyte namely B. amyloliquefaciens on mycelial growth of observed through Scanning Electron Microscopic (SEM) analysis. The lipopeptide antibiotic genes present in the effective entophytes was identified by PCR amplification using gene specific primers. Furthermore, glass house and field experiments were conducted to evaluate the efficacy of effective endophytes against target leaf spot of cotton.

Results: A total of 10 bacterial endophytes were screened for their antifungal potential against C. cassiicola by dual culture technique under in vitro conditions. Among these, Bacillus amylolquefaciens stand out as a superior endophyte in inhibiting growth of the C. cassiicola by 72.0 per cent. This was followed by B. safensis, B. megaterium and B. subtilis which repressed the growth by 69.1, 68.8 and 64.1 per cent respectively. Scanning Electron Microscopic observation revealed the hyphae of C. cassiicola exhibited morphological abnormalities such as shrinkage, disintegration and lysis when co cultured along with B. amylolquefaciens. The lipopeptide antibiotics genes such as surfactin, iturin and fengycin were detected in B. amylolquefaciens through PCR amplication using gene specific primers. Foliar application of liquid formulation of B. amylolquefaciens @0.5 % twice first at 45 DAS and second at 60 DAS was found to be promising in suppressing the target leaf spot incidence and increasing the yield under both glass house and field conditions. This treatment also promoted the growth by enhancing the root and shoot length of cotton under glass house conditions. Our results demonstrated that, B. amylolquefaciens could be used as an eco-friendly alternative to chemicals for the sustainable management of target leaf spot in cotton.

Lignocellulose Degradation of Cotton Stalks through Solid State Fermentation Using Fungal Isolates

Diksha Ramteke — 2026-03-25

Background and Aim: Lignocellulosic biomass such as cotton stalks represents an abundant agricultural residue with significant potential for conversion into value-added products; however, its utilization is limited due to high lignin content. This study aimed to isolate and identify efficient lignocellulolytic fungi capable of enhancing cotton stalk degradation through solid-state fermentation (SSF).

Methodology: A total of 26 fungal isolates were obtained from soil samples collected in Nagpur District, Maharashtra, India, and screened for cellulolytic and ligninolytic activities. Promising isolates were identified through ITS gene sequencing, and their enzymatic activities including carboxymethyl cellulase (CMCase), β-glucosidase, and filter paperase (FPase) were evaluated under SSF conditions.

Results: Four efficient fungal isolates were identified as Trichoderma asperellum, Trichoderma sp., Penicillium chrysogenum, and Alternaria sp. Among them, Alternaria sp. CICR4 exhibited the highest CMCase activity (30.46 IU mL⁻¹), while T. asperellum CICR1 showed the maximum β-glucosidase activity (40.8 IU mL⁻¹). Alternaria sp. CICR4 demonstrated the highest FPase activity (25.6 IU mL⁻¹). Temperature optimization indicated that 30 °C was the most favorable condition for maximum enzyme production. Under solid-state fermentation of cotton stalks, co-culturing P. chrysogenum CICR3 with T. asperellum CICR1 significantly enhanced enzymatic activities, resulting in CMCase activity of 28.4 IU mL⁻¹, β-glucosidase activity of 21.7 IU mL⁻¹, and FPase activity of 24.4 IU mL⁻¹.

Conclusion: The study demonstrates that selected lignocellulolytic fungi, particularly T. asperellum CICR1 and P. chrysogenum CICR3, possess strong enzymatic potential for efficient degradation of cotton stalks under solid-state fermentation. The synergistic interaction observed in co-culture significantly enhances cellulolytic enzyme production, indicating a promising strategy for sustainable lignocellulosic biomass valorization and agricultural waste management.

Molecular Characterization and Genetic Diversity of Rice Stripe Necrosis Virus (RSNV) in Burkina Faso

Emmanuel Kabore — 2026-03-25

Rice stripe necrosis virus (RSNV) is a threat to rice cultivation in Burkina Faso causing huge crop losses. The objective of this study was to perform a molecular characterization of the diversity of RSNV viral isolates from Burkina Faso, in order to develop effective control strategies for the virus to producers. Samples of symptomatic rice leaves, characterized by stunted growth and the presence of chlorotic spots, were collected from rice fields in four locations of Sudanian zone and subjected to total RNA extraction using Trizol. Amplifications for virus characterization were performed using the capsid protein (CP). They have been retranscribed into cDNA before being amplified by Polymerase chain reaction (PCR). Thus, the RSNV diversity has been analyzed through the sequencing of the capsid protein. The results indicated a grouping of the isolates into three (03) distinct groups, regardless of their geographical origin. Inter-isolate nucleotide diversity ranged from 0.2% to 5.5%. The highest nucleotide divergence (5.1%) was observed between sequence from Banfora and Karfiguela. In contrast, lower divergent rates (0.2%) were recorded between the sequences from Bama and Banfora, as well as between those from Bagre and Bama. This represents the first study of RSNV diversity based on capsid protein sequences in Burkina Faso. This study provides essential information for the development of effective and sustainable control strategies against RSNV, particularly through the development and deployment of resistant/tolerant rice varieties.

Characterization of Plant Growth Promoting Rhizobacteria of Bacillus and Pseudomonas Species from Soil Isolates through DNA Sequencing

Usha Verma — 2026-03-30

Plant growth-promoting rhizobacteria (PGPR) play a crucial role in sustainable agriculture by enhancing plant growth, nutrient availability, and resistance to environmental stresses. The present study aimed to isolate, characterize, and molecularly identify Bacillus and Pseudomonas species from soil samples collected from the campus site of Doon (PG) Paramedical College, Dehradun, Uttarakhand. Isolation was performed using serial dilution and selective media techniques, followed by morphological and biochemical characterization. Three bacterial isolates (S1, S2, and S3) were obtained and screened for plant growth-promoting traits including phosphate solubilization, indole-3-acetic acid (IAA) production, and siderophore synthesis. Among the isolates, S2 (Pseudomonas sp.) exhibited the highest phosphate solubilization zone (16 mm), maximum IAA production (0.8387 OD at 72 h), and significant siderophore activity (1.5733 OD at 450 nm). Thin layer chromatography confirmed IAA production with Rf values ranging from 0.46 to 0.66. Plant inoculation studies using Hordeum vulgare (barley) and Solanum lycopersicum (tomato) demonstrated enhanced shoot growth in treated plants compared to controls, with Pseudomonas isolate showing superior performance. Molecular identification through 16S rRNA gene sequencing confirmed isolate S1 as Priestia aryabhattai (formerly Bacillus coagulans), belonging to the family Bacillaceae. The findings highlight the multifunctional plant growth-promoting potential of native Bacillus and Pseudomonas strains and support their application as eco-friendly biofertilizers and biocontrol agents for sustainable agricultural practices.

Production of Asparaginase Enzyme by Aspergillus niger Isolated from Soil

R. C. Ndife — 2026-03-30

Asparaginase is an enzyme which converts L-asparagine to L-aspartic acid produce asparaginase. Eukaryotic microorganisms like yeast and filamentous fungi such as Aspergillus, Penicillium and Fusarium species, have a potential for L-asparaginase production without side effects. The study was designed to produce Asparaginase by fungi isolated from the soil. Different soil samples were collected from various locations around Uli in the Ihiala Local Government area and used for the isolation of fungi. The fungal isolates were screened for asparaginase production. Thereafter, the best fungal isolates were selected and used for optimisation studies. Pure cultures of the fungi isolates were obtained after repeated subculture on SDA plates. The multivariate regression tests were used as a tool, using SPSS version 25. Among the 43 fungi isolated, 15 were positive for L-apsaraginase production. It was found that fungal isolate wds-8 (from waste dump site soil) produced the highest L-asparaginase yield of 380 U/mL, followed by isolate gds-7 (from garden soil) with 280 U/mL and isolate ccf-3 (from cassava cultivated field soil) with 250 U/mL. The isolate wds-8 was selected as the best producer and was used for further study. It was identified as Aspergillus niger and designated as Aspergillus niger wds-8. Maximum L-asparaginase yield (572 U/mL) by Aspergillus niger wds-8 was observed at an incubation period of 96 h; thereafter, the yield gradually decreased till 168 h. The highest L-asparaginase production corresponded with the dry mass yield of 1.7 g/100 mL. Sucrose stimulated the highest L-asparaginase yield of 655 U/mL, followed by galactose with 503 U/mL. Ammonium sulphate stimulated the highest L-asparaginase yield of 776 U/mL, followed by ammonium chloride with 657 U/Ml. The results of the study show that some asparaginase-producing fungi are present in the soil.

Role of Microorganisms in Oil Reservoir Souring and Its Mitigation Strategies

Rawia Mansour — 2026-03-24

Petroleum microbiology offers substantial environmental and industrial benefits by harnessing the natural capabilities of microbes to interact with crude oil and refined petroleum products. Microorganisms are found worldwide in oil reservoirs, where they degrade the oil and alter its quality. Oil reservoirs are challenging environments for microorganisms due to their high toxicity, hydrophobicity, low water activity, and extreme conditions, including high temperature, salinity, and pressure. Despite these harsh factors, oil reservoirs host a diverse range of bacteria and archaea, including fermenters, acetogens, methanogens, and organisms that reduce sulfate, nitrate, and iron. It is crucial to understand the microbiology of oil reservoirs, as oil remains one of the most vital resources for industry and energy. Sulfate-reducing bacteria (SRB) convert sulfate to sulfide, a hazardous and corrosive compound that impacts metallurgy, capital and operating costs, and operational safety. Reservoir souring is the process where a reservoir that previously did not contain any hydrogen sulfide (H₂S) begins to produce sour fluids containing H2S due to microorganisms. The genetic, enzymatic, and physiological aspects of the sulfate-reduction process have been extensively studied in pure cultures in laboratory settings. Furthermore, advancements in DNA sequencing have identified new groups of microorganisms, including archaea, that can contribute to reservoir souring. Reservoir souring is primarily caused by sulfate reducing microorganisms, which leads to the formation of H₂S in oil reservoirs during water flooding, although both biotic and abiotic processes are involved. This review discusses the occurrence of reservoir souring due to specific types of sulfate-reducing microorganisms and outlines strategies for managing this issue through the injection of various chemicals. In addition, the manuscript provides useful insights that can guide future research and improve reservoir management practices in the oil and gas industry.

Integrated Disease Management in Silkworm (Bombyx mori L.): A Comprehensive Review for Sustainable Sericulture

K. Ranganatha — 2026-03-30

Aims: This review critically synthesizes current knowledge on the major diseases affecting the mulberry silkworm (Bombyx mori L.) and evaluates the paradigm shift towards Integrated Disease Management (IDM). It aims to provide a comprehensive framework for enhancing silkworm health and ensuring sustainable cocoon production by integrating disease control with broader agronomic practices.

Study Design: A comprehensive and critical literature review.

Methodology: This study synthesizes peer-reviewed literature on silkworm pathology, transmission dynamics, economic impacts and management strategies. The literature search was conducted across major scientific databases, focusing on recent advancements. It evaluates traditional preventive, chemical and microbial methods alongside emerging innovations such as probiotics, host-plant resistance, RNA interference (RNAi) and artificial intelligence (AI). The review also integrates findings related to mulberry nutrition and weed management to contextualize disease susceptibility within the broader agroecosystem.

Results: The review confirms that infectious diseases cause substantial crop losses, ranging from 15% to over 50%, severely impacting cocoon yield and quality. It provides a detailed classification and symptomatology of viral, bacterial, fungal and protozoan diseases. The analysis identifies IDM-which combines stringent hygiene, environmental regulation, the use of probiotics and the development of disease-resistant silkworm strains-as the most effective and sustainable strategy. Furthermore, agronomic stressors, such as poor mulberry leaf nutrition and intense weed competition, exacerbate silkworm susceptibility to pathogens. Emerging technologies like molecular diagnostics and AI-driven monitoring show significant potential for early detection and proactive management.

Conclusion: Adopting a holistic IDM framework is imperative for the long-term viability of the sericulture industry. This approach must extend beyond direct pathogen control to include optimized mulberry nutrition and integrated weed management, thereby reducing host stress and enhancing innate immunity. The integration of advanced biotechnologies and climate-resilient practices will be crucial for safeguarding silkworm health, ensuring sustainable cocoon production and mitigating the adverse effects of pathogen evolution and climate change.