Indigenous Isolates Research Articles

Isolation, Identification and Molecular Characterization of Indigenous Bacterial Isolates from Textile Effluent and Contaminated Soil using 16s rRNA Sequencing

Textile industry effluent poses a serious environmental threat. Many physical and chemical methods for treating wastewater have been used, but due to high operating costs, a suitable alternative is required. As a result, the study focuses on the use of biological organisms with bioremediation potential which leads to the development of cost-effective and nontoxic methods. The present study focuses on the isolation of possible bacterial isolates from textile effluent contaminated soil and effluent. A total of four bacterial isolates were successfully isolated, three from textile industry effluent contaminated soil and one from textile industry effluent. Based on the results of morphological, biochemical and molecular datasets, the current study identified bacterial isolates belonging to three genera: Brevibacillus, Achromobacter and Pseudomonas. The 16S rRNA sequence technique was used to characterize and identify the bacterial isolates. The isolates were submitted to GenBank like Achromobacter xylosoxidans KUESCCHK-6, Pseudomonas aeruginosa KUESCCHK-5, Achromobacter insuavis KUESCCHK-7 and Brevibacillus panacihumi KUESCCHK-8 with accession numbers OM475749, OM475764, OL797980 and OM475766 respectively. Bacteria can survive in contaminated environments because of their metabolic ability to use available resources and ability to find a suitable niche.

Occurrence of entomopathogenic nematodes, Oscheius myriophilus Poinar in Thailand: Preliminary characterization of novel isolates and biological control potential against insect pests

AbstractNumerous nematodes in the genus Oscheius possess entomopathogenic abilities. These nematodes also kill their insect hosts by releasing their symbiotic bacteria within 48–72 h. In this study, 12 indigenous isolates of Oscheius myriophilus based on molecular, morphological, and morphometric studies were recovered from different undisturbed soils in Thailand. Moreover, the virulence of 12 O. myriophilus at a rate of 25 IJs/cm2 against fifth‐instar larvae of Galleria mellonella ranged from 56%–86% after 72 h of exposure. Oscheius myriophilus EPNKU40 exhibited the highest efficacy in causing mortality in the insect larvae. It also killed third‐instar larvae of Spodoptera litura and Spodoptera exigua up to 60% after 72 h of exposure. The median lethal concentration (LC50) values of O. myriophilus EPNKU40 against G. mellonella larvae after 48 and 72 h of exposure were 11 and 4 IJs/cm2, respectively. The discovery of O. myriophulus is the first record in Thailand characterized using morphological, morphometric, and molecular diagnostic tools, which have shown lethal effects against insect pests and can later be utilized as biocontrol agents after several comprehensive assessments.

Isolation of two indigenous Bacillus thuringiensis isolates from Natore District in Bangladesh

Isolation of two indigenous Bacillus thuringiensis isolates from Natore District in Bangladesh

Green Production and Characterization of Silver Selenide Nanoparticles Using the Cladosporium sp. ssf15 Cell-free Extract

Background: Chalcogenide nanoparticles (NPs), such as silver selenide NPs (Ag2Se NPs), are used as quantum dots in pharmaceutical formulations for the detection of cancer cells, as well as in solar cells, sensors, and electrical, optical, and magnetic instruments. Objectives: The physical-chemical production of metal NPs is expensive and difficult and pollutes the environment due to the use of dangerous chemicals and by-products. Hence, green chemistry-based processes must be developed as a reliable alternative. This study investigated indigenous aquatic fungal isolates for Ag2Se NP synthesis. Methods: Visual examination, UV-Vis spectroscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS) analysis, and energy-dispersive X-ray spectroscopy (EDX) tests confirmed the synthesis of Ag2Se NPs. Based on the characteristics of the colony, the microscopic features, and the polymerase chain reaction (PCR) amplification of the ITS1-5.8S-ITS2-ITS4 areas, the selected fungal isolate’s identity was established. Results: The SEM analysis revealed that Cladosporium sp. ssf15 produced spherical Ag2Se NPs with an average diameter of 37.84 nm. The average size of NPs synthesized by the fungal isolate was determined to be 40.92 nm using the DLS analysis, and the polydispersity index (PDI) was determined to be 0.26. Based on the results, regular spherical Ag2Se NPs with correct dispersion distribution were produced using 2 mM AgNO3 and 1mM selenious acid (H2SeO3). Conclusions: The results of this research have the potential to contribute to the development of a biocompatible approach and innovative research methods for investigating the green synthesis of Ag2Se NPs using fungal isolates.

Characterization of insecticidal metabolite oosporein in Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno, a geographically distinct isolate from Kerala, India

Lecanicillium saksenae, an indigenous isolate from Kerala, India is a potent entomopathogen against hemipteran pests. The wine-red pigmentation produced by this isolate distinguishes it from many other isolates of L. saksenae reported across the globe. This study, therefore, sought to isolate and characterize the pigment molecule. The wine-red pigment extracted through liquid - liquid partition of the fungal culture was subjected to structural characterization and identification through UV spectrometry, Fourier Transform Infrared Spectrometry (FTIR), High Resolution Liquid Chromatography, Mass Spectrometry (HR-LCMS) and Nuclear Magnetic Resonance Spectrometry (NMR). It was unambiguously identified as a dibenzoquinone compound, oosporein, a known bioactive insecticidal metabolite. The empirical formula of which was confirmed as C14H10O8 and molecular weight, m/z 306.22. The dose dependent bioefficacy of oosporein with 1000 ppm at 96 h recorded a mortality of 60.25 per cent in nymphs of brinjal mealybug, Coccidohystrix insolita, while it was still lower (51.00%) in adults. In this study, we could identify that L. saksenae reported from Kerala, India was geographically distinct. Sequence analysis based on 18srDNA and phylogenetic analysis confirmed the species identity of this indigenous isolate with that of L. saksenae documented in NCBI. This finding paves the way for the possibilities of tapping the potential of bioactive metabolites for pest management and uplifting the species as a potent bioagent in insect pest management programmes.

Colonization and endophytic effect of Beauveria bassiana (Bals.-Criv.) Vuill. UHSB-END1 against Myzus persicae (Sulzer) and Plutella xylostella (L.) in cabbage

BackgroundFungal microbial biocontrol agent playing an important role in sustainable pest management with low cost. Conidial contact with cuticle is sufficient to cause disease in insects by entomopathogenic fungi (EPF) compared to bacteria and viruses which required ingestion of contaminated food. The field level application of fungi resulted inconsistent in their efficacy against insects as they withstand in the agroecosystem with adverse environmental conditions. To overcome this bottleneck, endophytic EPF, Beauveria bassiana (Bals.-Criv.) Vuill. (Cordycipitaceae: Hypocreales), is well-studied for the management of insects of cultivated crops and got promising results. The colonization of endophytic isolates varied from one host plant to another and virulence against insects too. Hence, the study was undertaken to know the colonization of indigenous B. bassiana UHSB-END1 isolate in cabbage plant and its efficacy against major insects of cabbage.ResultsThe indigenous isolate of B. bassiana UHSB-END1 was able to colonize cabbage in all the methods of inoculations (seed treatment, seedling root dip, soil drenching, foliar spray and combination treatment) at 30, 45 and 60 days of post-inoculation (dpi). However, the colonization of the fungus inside the cabbage was restricted to tissues of inoculation, and movement from the site of inoculation to other parts of the plant was poor. In the present study, colonization was the highest at 30 dpi in all methods of colonization with restricted colonization to the site of exposure of fungus. Further, in vivo and in planta assay confirmed the effectiveness of B. bassiana UHSB-END1 colonized cabbage against Myzus persicae (Sulzer) and Plutella xylostella (Linnaeus). Under in vivo conditions the maximum mortality of M. persicae and P. xylostella was recorded at 30 dpi. It was decreased slightly at 45 dpi, and the lowest morality was recorded at 60 dpi. In planta experiment also proved better efficacy against both the test insects. Wherein mortality of M. persicae ranged from 22 to 36% five days after release (DAR), it was increased to 48–68% at 10 DAR and reached highest mortality rate at 15DAR (72–96%). Similarly, mortality of P. xylostella ranged from 14 to 24% after five DAR, and it was 27–44% at 10 DAR, and maximum mortality rate of larvae were recorded at 15 DAR (64–96%).ConclusionThe present study reported 100% colonization of cabbage plant by indigenous B. bassiana UHSB-END1 at 30 dpi in combination of treatment and showed a maximum efficacy in managing the population of major insects of cabbage. Introducing this indigenous isolate will pave a ray of hope in managing the both key insects (P. xylostella and M. persicae) in cabbage agroecosystem without disturbing the environment and further helps in production of cabbage with minimum pesticide residue for consumers.

Screening of indigenous Rhizobacteria isolates from Patchouli Rhizosphere producing HCN, Siderophores and Chitinolytic Enzymes

The consortium of bacteria that inhabit the rhizosphere, acting as plant growth promoting rhizobacteria is known as indigenous rhizobacteria. Rhizobacteria can produce chemical compounds that can protect plants from pathogens and various plant-disturbing organisms. Optimization of the growth and yield of patchouli can be done by utilizing the potential of rhizobacteria derived from patchouli rhizosphere. This study aims to obtain rhizobacteria capable of producing secondary metabolites of HCN compounds, siderophores and chitinolytic enzymes which are thought of as biocontrol agents in plant protection. The soil samples used were taken from patchouli rhizosphere areas in three locations, namely Alue Abed, Aceh Jaya and Krueng Itam and Purwosari, Nagan Raya. The exploration results obtained 4 isolates of rhizobacteria from Alue Abed, Calang, 8 isolates from Krueng Itam, Nagan Raya and 37 isolates from Purwosari, Nagan Raya. Based on the test results of qualitative and quantitative physiological properties, 34 isolates were able to produce HCN, 49 isolates produced siderophores and 42 isolates were able to carry out chitinolytic enzyme activity. Rhizobacteria isolate producing HCN, siderophores and chitinolytic enzymes are potential indigenous rhizobacteria candidates and potential for future testing as bio-protections of plants from pathogen attack.

Biodegradation Test of Polluted River Caused by Domestic Wastewater Using Indigenous Bacteria in the Way Tomu Watershed, Ambon City

Nowadays, the rivers are often used by residents around the river as the final disposal of domestic wastewater that causes the rivers to become polluted. Biodegradation is an alternative to wastewater treatment as an effort to solve water pollution which is often carried out using bacteria that have the potential to decomposers in the biodegradation process, especially indigenous bacteria. This study aims to identify and obtain isolates, combinations, and characteristics of the indigenous bacteria isolate that have the potential as a biodegradation agent for polluted river caused by domestic wastewater in the Way Tomu watershed, Ambon City. In this study, isolates of indigenous bacteria that were isolated and purified were tested for protease and amylase enzyme activity to select isolates to be used in the biodegradation process testing consisting of parameters pH, COD, and TSS as indicators of the biodegradation. Afterward, the isolates that have the best potential as biodegradation agents will be characterized and biochemical tests will be carried out to identify the general characteristics of these isolates. The results showed that the combination of Genus Aeromonas, Bacillus, and Pseudomonas as isolates of indigenous bacteria that has the best potential as an agent for the biodegradation of polluted river caused by domestic wastewater. The benefit of this research is as initial information and consideration for alternative treatment of polluted rivers caused by domestic wastewater using indigenous bacteria isolates as an effort to resolve river pollution, especially the rivers in Ambon City.

Surveillance of Bacterial Canker of Peach in Azad Jammu and Kashmir, and its Bio-Management

Bacterial canker of peach caused by Pseudomonas syringae is an increasing problem in Azad Jammu Kashmir with more than 50 pathovars on the basis of host. A detailed survey was conducted in peach growing areas of Azad Jammu and Kashmir for the determination of disease prevalence and incidence. Pathogen was isolated and characterized from the collected samples using LOPAT and GaTTA scheme. Furthermore the results of biochemical identification was confirmed using PCR followed by sequencing of obtained expected bands. For the bio-management of virulent pathogenic strains indigenous rhizobacterial isolates were obtained, characterized and evaluated using dual culture as well as in a greenhouse pot experiment against P. syringae pathovars. During a positive sampling method used for the surveillance it was found that maximum disease prevalence was 75% in district Bagh while there was 25% disease prevalence found in Haveli and Sudhanoti. Similarly maximum disease incidence was found in district Bagh that was 16%. A total of 32 isolates were recovered from the collected samples that were further screened on the basis of their virulence. It was found that the total of 18 isolates screened were similar to the already reported strains of P. syringae pv. syringae (Pss) on the basis of biochemical and molecular tools. From total 17 rhizobacterial isolates recovered were subjected to dual culture technique and was found that 06 isolates showed promising zone of inhibition upto 11.5 mm. The results of greenhouse evaluation revealed that the minimum disease incidence was recorded 3% using R-9 and R-17 in consortium against Pss as compared to the control treatment (39%). It was concluded that the ecofriendly management practices against this destructive disease must be adopted and appreciated

Whole-Genome Sequence of Lactococcus lactis Subsp. lactis LL16 Confirms Safety, Probiotic Potential, and Reveals Functional Traits.

Safety is the most important criteria of any substance or microorganism applied in the food industry. The whole-genome sequencing (WGS) of an indigenous dairy isolate LL16 confirmed it to be Lactococcus lactis subsp. lactis with genome size 2,589,406 bp, 35.4% GC content, 246 subsystems, and 1 plasmid (repUS4). The Nextera XT library preparation kit was used to generate the DNA libraries, and the sequencing was carried out on an Illumina MiSeq platform. In silico analysis of L. lactis LL16 strain revealed non-pathogenicity and the absence of genes involved in transferable antimicrobial resistances, virulence, and formation of biogenic amines. One region in the L. lactis LL16 genome was identified as type III polyketide synthases (T3PKS) to produce putative bacteriocins lactococcin B, and enterolysin A. The probiotic and functional potential of L. lactis LL16 was investigated by the presence of genes involved in adhesion and colonization of the host's intestines and tolerance to acid and bile, production of enzymes, amino acids, and B-group vitamins. Genes encoding the production of neurotransmitters serotonin and gamma-aminobutyric acid (GABA) were detected; however, L. lactis LL16 was able to produce only GABA during milk fermentation. These findings demonstrate a variety of positive features that support the use of L. lactis LL16 in the dairy sector as a functional strain with probiotic and GABA-producing properties.

DIVERISTY and enzymatic potential of indigenous bacteria from unexplored contaminted soils in Faisalabad

Bacteria residing in contaminated waste soil degrade and utilize organic and inorganic material as a source of nutrients as well as reduce environmental contamination through their enzymatic machinery. This enzymatic potential of indigenous bacteria can be exploited at industrial level through detailed screening, characterization, optimization and purification. In present study, diversity and enzymatic potential of indigenous bacteria was investigated through qualitative and quantitative screening methods from unexplored contaminated soil waste sites in Faisalabad. Shannon diversity (H’) index revealed that twenty-eight soil samples from four contaminated sites were highly diverse of amylase, protease and lipase producing bacteria. Maximum protease producing bacteria were detected in fruit waste (1.929 × 107), whereas amylase and lipase producing bacteria were found in industrial (1.475 × 107) and (5.38 × 106), in household waste soil samples. Most of the indigenous bacterial isolates showed potential for multiple enzymes. An isolate OC5 exhibited capability for amylase production and optimization at a wider range of cultural conditions; pH (6–8), temperature (25 °C, 37 °C, 45 °C), incubation time (24–72 h), and NaCl concentrations 0.5–13%, using (1%) starch and lactose as substrates. An isolate OC5 was identified by molecular identification and phylogenetic analysis showed 99% sequence similarity with Bacillus spp. ANOVA was used to analyzed all data statistically. This study enhances the importance of initial screening and reporting of industrially potent indigenous bacteria from unexplored contaminated waste soils. In future, indigenous bacteria in contaminated wastes may be good candidates to solve various environmental pollution problems.

Degradation of dibutyl phthalate and diethyl phthalate by indigenous isolate Bacillus sp. MY156

Dibutyl phthalate (DBP) and diethyl phthalate (DEP) are among the most extensively utilized plasticizers and widely exist in the environment causing adverse effect on human health. Previous studies on these phthalic acid esters (PAEs) biodegradation mainly involved individual substrates. However, these contaminants are more possible existed in mixtures. This work explored the biodegradation of DBP and DEP and their interactions using the indigenous isolate Bacillus sp. MY156. The results demonstrate DBP could be completely degraded by strain MY156 with high efficiency, while DEP showed relatively lower removal efficiency (72%) in 120 h. The binary substrate removal results revealed the coexistence of DBP and DEP had no significant influence on the degradation of each under the optimal pH and temperature. Nevertheless, slight retardation of the removal efficiency for DEP noticed as co-existed with DBP demonstrated their removal was possibly affected through the substrate competition. The dehydrogenase activity assay illustrated the behaviors of dehydrogenases caused by long-side chains PAEs were higher than PAEs with shorter alkyl chains. The isolate Bacillus sp. MY156 showed a positive utilization potentiality for bioremediation of PAEs-polluted environment.

Enhanced removal of triclosan from contaminated water by indigenous isolate Burkholderia sp. L303

Triclosan (TCS), one of the most widely used antimicrobial agents, is frequently detected at wastewater treatment plants and environmental matrices including soil, water, sediment, and biota samples. In this study, a TCS-degrading bacterium was isolated from local activated sludge and identified as Burkholderia sp. L303. Strain L303 could degrade TCS (0.5-8 mg/L) as sole carbon source. The optimal condition was 35°C and pH 7. The in-vitro assay with the glucose-enriched cells showed the ability of TCS degradation in real water samples, indicating the functional enzyme expressed in the absence of TCS. The bioaugmentation of strain L303 in non-sterile wastewater showed better degradation rate than that in the control groups. The community profiles showed the potential cooperative interactions between strain L303 and indigenous bacteria, thereby enhancing the TCS degradation in the real polluted water. The finding of this study could facilitate in developing appropriate bioaugmentation strategy by using live bacteria or active enzyme and in designing beneficial community interactions within native and external species for treating TCS-laden waters.

Mycoremediation of Heavy Metals from Electronic Waste Polluted Water Using Indigenous Fungi and Its Implications

Background: Heavy metals (HM) pollutants are crucial environmental and public health problems due to their toxicity, which has implications on public health. The site of study has been reported to be densely polluted with heavy metals as a result of dumping used electronic wastes into the water body.
 Aim: This study was carried out to determine the biosorption potentials of indigenous fungi isolates in reducing heavy metal present in electronic wastes polluted water body.
 Study Design: This was a laboratory based study.
 Place and Duration of Study: The study was conducted at the Microbial Resources Research Laboratory, Department of Pure and Applied Biology, Ladoke Akintola University of Technology Ogbomoso, Nigeria from July 2021 to June 2022.
 Methodology: Heavy metal polluted water sample was collected near the dumpsite of e-waste in Alaba International market, Lagos Nigeria. Fungi were isolated from the polluted water sample by carrying out serial dilution. Pure colonies were obtained and stored at 4°C. Media formulations (MF) trials for the biosorption process was achieved using brewery waste and honeycomb extracts. Exactly 200 ml of MF were dispensed into a 500 ml Elmeryer flask containing 100 ml of the e-waste polluted water and fugal discs. Atomic absorption spectrophotometer was used to determine the heavy metal concentration in the water samples. The biological interactions of the fungi with the polluted water sample was monitored using Fourier transform infrared (FTIR) spectroscopy. The pH, electrical conductivity and other physicochemical parameters were also determined.
 Results: Trichoderma harzianum, T. viride, Fusarium oxysporum, Aspergillus flavus and A. niger were isolated from the heavy metal polluted water samples. Heavy metal such as Pb (13.30 mg/L), Cd (16.50 mg/L), Cr (6.41 mg/L), Ni (3.81 mg/L), Zn (8.85 mg/L), Cu (8.33 mg/L), Fe (5.60 mg/L) had values which were higher than the acceptable limits. Biosorption efficiency of each of the fungus in reducing the metals present in the sample was in the increasing order of A. niger<A. flavus<F. oxysporum<T. viride<T. harzianum. FTIR showed that some peaks were shifted to lower wavenumber as a result of the interactions of the fungus with the heavy metal in the water sample. This study revealed that T. harzianum had the highest biosorption efficiency for the removal of heavy metal in the polluted water sample.
 Conclusion: It is essential that heavy metals be removed from polluted water body to avoid its deleterious effects on public health. This can be achieved biologically using any of the fungi isolated in this work.

Role of Carrier Media and Types of Indigenous MVA Isolates on Soil Quality in Corn Plants in the Dry Land of West Nusa Tenggara

Corn plants have many benefits and are needed by the government as a national food reserve. West Nusa Tenggara (NTB) maize production fluctuated. If managed optimally, dry land agriculture in NTB can provide benefits for increasing agricultural production, especially corn production. The sustainability of dry land farming systems must be continuously improved even with various farming strategies with the main objective of improving soil fertility and overcoming drought stress constraints. One of the efforts to increase the productivity of NTB's dry land is the use of arbuscular vesicular mycorrhizal biofertilizers which are an alternative to improve the quality of soil and plants. Arbuscular vesicular mycorrhiza will colonize and infect roots maximally if using a carrier media that is compatible with MVA inoculant. Appropriate MVA carrier media will provide optimal environmental conditions for host plant growth. The aim of the research was to determine the role of Indigenous MVA and carrier media on soil quality in dryland maize. The research was carried out on corn plants using different carrier media and native MVA types. The study was designed as a factorial study using a completely randomized design (CRD) with 2 factors, namely the type of indigenous MVA isolates with 3 treatment levels and the Carrier Media Type factor with 4 treatment levels. There were 12 treatment combinations that were repeated 3 times so that 36 treatment combinations were obtained which were carried out at the Green House of the Faculty of Agriculture, Nahdhatul Wathan University, Mataram from December 2020 to February 2021. The results showed that the MVA type factor, the MVA isolate had a significantly different effect for all observation parameters, namely soil water content, soil pH, soil total N content and soil available P content, the best isolate was Glomus sp. The carrier media factor gives the result that the type of carrier media has a significant effect on the parameters of observing soil water content, soil total N content and soil pH with the best carrier media being rice husk charcoal biochart

Isolation, Identification, and Antibacterial Assay of Indigenous Bacterial Isolates from Apis cerana Honeycomb

Apis cerana is a honey bee species with a cavity hive known as the eastern honey bee. Honey bee hives have Indigenous bacteria that have antimicrobial potential. Indigenous bacteria are free bacteria that can synthesize nitrogen compounds, sugars, and other bioactive substances. This study aims to isolate, identify and test the antibacterial of Indigenous bacteria isolate Apis cerana against gram-positive Staphylococus aureus and gram-negative bacteria Escherichia coli. This study used a descriptive research method to obtain the data from laboratory experiments. The study consisted of isolating Indigenous bacteria, identifying and testing the antibacterial agar diffusion method. The study results obtained seven isolates of AC 1, AC 2, AC 3, AC 4, AC 5, AC 6, AC 7 Indigenous bacteria from Apis cerana nests. AC 1 isolate has similarities with the genus Streptococcus, AC 2 isolates have similarities with the Klebsiella genus, while AC 3 isolates have similarities with the Bacillus genus, and AC 4, AC 5, AC 6 and AC 7 isolates have similarities with the Citrobacter genus. Indigenous bacterial isolates with potential antibacterial potential where the most significant inhibition against Staphylococus aureus bacteria was shown by isolate AC 1 (10.79 mm). At the same time, the smallest was found in isolate AC 7 (8.52 mm). The most significant inhibition against Escherichia coli bacteria was shown by isolate AC 1 (9.0 mm) while the smallest was found in isolate AC 3 (7.4 mm). Apis cerana nests have indigenous bacteria that have the potential to produce antibacterial substances

Native Trichoderma Isolates from Soil and Rootstock to Fusarium spp. Control and Growth Promotion of Humulus lupulus L. Plantlets

Fusarium genus is a wide host phytopathogen causing significant losses in multiple crops, including hops. There is limited information on the sustainable management of Fusarium spp. in hop fields. Trichoderma is an endophytic fungus used in agriculture as a biological control agent (BCA) and as a plant growth promoter. It has been used to antagonize Fusarium spp. in other crops. The objective of the current study was to identify indigenous hop field Trichoderma isolates with biocontrol and hop growth promotion capabilities. Three isolates of Fusarium and eleven autochthonous Trichoderma isolates collected from sustainable hop fields were evaluated in this work. Direct confrontation tests (the physical interaction between the pathogen and BCA and their competition for space and nutrient resources) and membrane tests (the capacity of the BCA to produce metabolites or enzymes through a cellophane film and inhibit the development of the pathogen) assessed the antagonism of these Trichoderma isolates against Fusarium culmorum, F. sambucinum, and F. oxysporum. A bioassay with hop plantlets inoculated with a spore suspension of Trichoderma was performed to assess its hop growth enhancement. T. hamatum (T311 and T324), T. virens T312, and T. gamsii T327 showed high growth inhibition of Fusarium spp. phytopathogens and high plant growth promotion. Native Trichoderma isolates from sustainable hop-producing soils have great potential as BCAs and hop growth promoters.

Biocontrol Potential of Entomopathogenic Nematodes against Odontotermes obesus (Blattodea: Termitidae) under Laboratory and Field Conditions

Odontotermes obesus (Blattodea: Termitidae) is a prevalent subterranean wood-eating termite species that causes damage to mature trees, saplings and seedlings. The efficacy of most synthetic insecticides against this notorious pest has been compromised primarily because of its enigmatic feeding behavior and development of resistance to a number of insecticides. It has therefore become necessary to explore other alternative biologically sound and low-impact termite control methods, particularly for use in forests. Hence, this study was designed to verify the efficacy of different indigenous EPN isolates (Steinernema carpocapsae, Heterorhabditis bacteriophora and Heterorhabditis indica) against workers of Odontotermes obesus. The pathogenicity of each nematode isolate was assessed in laboratory conditions using filter paper and sawdust bioassay at two different temperatures (16 ± 1 and 26 ± 1 °C). Additionally, the efficacy of the nematode species was also assessed in field conditions. The results of the experiments revealed that the mortality of termite workers was more pronounced in sawdust bioassay in comparison with filter paper bioassay at both the tested temperatures. The mortality response in both bioassays was more pronounced at the higher temperature. A significantly higher mortality was recorded at both tested temperatures for S. carpocapsae followed by H. bacteriophora and H. indica. A dose-dependent positive mortality response was also recorded at both tested temperatures. Similar to the laboratory trials, the field applications of the three tested nematode species showed that maximum mortality was recorded for S. carpocapsae followed by H. bacteriophora and H. indica. It was therefore concluded that indigenous EPNs can provide more effective control of termites, possibly because of their direct interaction with pest species in the soil and the possibility of causing secondary infection through infected cadavers.

Effect of high-copper diet on transference of bla CTX-M genes among Escherichia coli strains in rats' intestine.

Both ceftiofur (CTO) and high copper are widely utilized in animal production in China, and the occurrence of CTX-M-carrying Escherichia coli in food-producing animals is increasing. There are some specific associations between in-feed high-level copper and antibiotic resistance, but research in Gram-negative bacteria such as E. coli remains scarce. This study aimed to evaluate the effect of high-copper diet on the horizontal transfer of bla CTX-M-1 among E. coli. A total of 32 male SPF rats aged 21 days were randomly assigned to the following four groups: control (6 mg/kg in-feed copper, C-), high copper (240 mg/kg in-feed copper, H-), CTO (6 mg/kg in-feed copper with oral CTO administration, C+), and high copper plus CTO (240 mg/kg in-feed copper with oral CTO administration, H+). All rats were orally inoculated with an E. coli strain harboring a conjugative plasmid carrying bla CTX-M-1, and the C+ and H+ groups were given 10 mg/kg of body weight (BW) CTO hydrochloride at 26, 27, and 28 days, while the C- and H- groups were given salad oil at the same dose. Fecal samples collected at different time points were used for the enumeration of E. coli on Mac plates or for molecular analysis using PCR, pulsed-field gel electrophoresis (PFGE), S1-PFGE, and Southern-blot hybridization. The results showed that the number of the bla CTX-M-1 gene in the H- group was higher and that the loss speed of this gene was slower compared with the C- group. After administration of CTO, the counts of cefotaxime-resistant E. coli were significantly higher in the C+ group than that in the corresponding control group (C+ vs. C-; H+ vs. H-). In the in vitro test, the results showed that the transfer rates of the conjugation induced by the H- (12 mmol/L) group were significantly higher than that of low copper (2 mmol/L) group. The indigenous sensitive isolates, which were homologous to the bla CTX-M-positive isolates of rat feces, were found by PFGE. The further analysis of S1-PFGE and Southern-blot hybridization confirmed that the bla CTX-M-1 gene in new transconjugants was derived from the inoculated strain. Taken together, high-copper diet facilitates the horizontal transfer and maintenance of the resistant genes in the intestine of rats, although the effects of antibiotics on bacterial resistance appearance and maintenance are more obvious.

Effects of Indigenous and Commercial Rhizobia on Growth and Nodulation of Soybean (Glycine max L) under Greenhouse Condition

Background: Soybean (Glycine max L.) is the most vital grain legume crop rich in protein and oil. The inoculation of rhizobia with soybean plays a very important role in increasing soil fertility via its contribution to biological nitrogen fixation. Objective: This study focuses on the evaluation of indigenous and commercial rhizobia on soybean nodulation and growth parameters. Methodology: Soil samples were collected from five districts for nodule trapping. The rhizobia were isolated using ‘plant induction following the standard procedures. The greenhouse experiments were arranged in a completed randomized design with three replications and two control units. The data were collected for plant height, nodule number, nodule dry weight, shoot dry weight, root length; root dry weight, total nitrogen and nitrogen-content. Results: The entire isolates were found gram-negative, without absorbing congo-red and did not grow on peptone glucose agar media. Slow grower isolates turned bromothymol blue with yeast extract mannitol agar medium into a moderately deep blue color but fast grower changed to yellow color. All isolates were tested on the sand induced nodule and were significantly superior to the negative control in terms of plant height, shoot dry weight, and nodule dry weight. The shoot dry weight of soybean rhizobial isolates on the sterilized sand experiment was ranging from 1.6 to 2.2g per plant and it was a highly significant correlation to the nodule number, nodule dry weight and root dry weight. Conclusion: The indigenous isolates were highly competent to all commercial rhizobia. This study encourages further evaluation of the field and molecular characteristics.