Growth Of Pathogens Research Articles

Three new discovery effector proteins from Candidatus Liberibacter asiaticus psy62 inhibit plant defense through interaction with AtCAT3 and AtGAPA.

We identify three SDEs that inhibiting host defence from Candidatus Liberibacter asiaticus psy62, which is an important supplement to the pathogenesis of HLB. Candidatus Liberibacter asiaticus (CLas) is the main pathogen of citrus Huanglongbing (HLB). 38 new possible sec-dependent effectors (SDEs) of CLas psy62 were predicted by updated predictor SignalP 5.0, which 12 new SDEs were found using alkaline phosphate assay. Among them, SDE4310, SDE4435 and SDE4955 inhibited hypersensitivity reactions (HR) in Arabidopsis thaliana (Arabidopsis, At) and Nicotiana benthamiana leaves induced by pathogens, which lead to a decrease in cell death and reactive oxygen species (ROS) accumulation. And the expression levels of SDE4310, SDE4435, and SDE4955 genes elevated significantly in mild symptom citrus leaves. When SDE4310, SDE4435 and SDE4955 were overexpressed in Arabidopsis, HR pathway key genes pathogenesis-related 2 (PR2), PR5, nonexpressor of pathogenesis-related 1 (NPR1) and isochorismate synthase 1 (ICS1) expression significantly decreased and the growth of pathogen was greatly increased relative to control with Pst DC3000/AvrRps4 treatment. Our findings also indicated that SDE4310, SDE4435 and SDE4955 interacted with AtCAT3 (catalase 3) and AtGAPA (glyceraldehyde-3-phosphate dehydrogenase A). In conclusion, our results suggest that SDE4310, SDE4435 and SDE4955 are CLas psy62 effector proteins that may have redundant functions. They inhibit ROS burst and cell death by interacting with AtCAT3 and AtGAPA to negatively regulate host defense.

Winter Rye Cover Crops Shelter Competent Squash Phyllosphere Bacteria to Reduce Pseudomonas syringae pv. lachrymans Growth and Angular Leaf Spot Symptoms.

Cover crops, a soil conservation practice, can contribute to reducing disease pressure caused by Pseudomonas syringae, considered one of the most important bacterial plant pathogens. We recently demonstrated that the phyllosphere (leaf surface) bacterial community structure changed when squash (Cucurbita pepo) was grown with a rye (Secale cereale) cover crop treatment, followed by a decrease of angular leaf spot disease symptoms on squash caused by P. syringae pv.lachrymans. Application of biocontrol agents is a known agricultural practice to mitigate crop losses due to microbial disease. In this study, we tested the hypothesis that some phyllosphere bacteria promoted when squash is grown on cover crops could be isolated and used as a biocontrol agent to decrease angular leaf spot symptoms. We grew squash during a 2-year field experiment using four agricultural practices: bare soil, cover crops, chemically terminated cover crops, and plastic cover. We sampled squash leaves at three different dates each year and constructed a collection of cultivable bacterial strains isolated from squash leaves and rye cover crop material. Each isolated strain was identified by 16S rRNA gene sequencing and used in in vitro (Petri dish) pathogen growth and in vivo (greenhouse) symptom control assays. Four bacterial isolates belonging to the genera Pseudarthrobacter, Pseudomonas, Delftia, and Rhizobium were shown to inhibit P. syringae pv. lachrymans growth and angular leaf spot symptom development. Strikingly, the symptom control efficacy of all strains was stronger on older leaves. This study sheds light on the importance of bacterial isolation from cover crop sources to promote disease control. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Study on the use of Imazalil to continuous cropping obstacle of Ganoderma lucidum caused by Xylogone ganodermophthora

BackgroundThe Xylogone ganodermophthora is a pathogenic bacterium that poses a significant challenge to the continuous cultivation of the Ganoderma lucidum fungus. This study aims to identify and investigate specific agents for the effective prevention and control of X. ganodermophthora, establishing a theoretical foundation for overcoming this persistent challenge in G. lucidum cultivation.ResultsUsing different G. lucidum soil as materials to study the presence of X. ganodermophthora in the soil. Additionally, the plate confrontation test was employed to investigate the impact of X. ganodermophthora on G. lucidum growth. The impact of physical factors and antibacterial agents on pathogenic bacteria was successfully carried out, with a further exploration of the effectiveness of field control. PCR amplification experiment and sequencing analysis verified that X. ganodermophthora existed in G. lucidum continuous cropping obstacle soil. This pathogenic bacteria has a significant inhibitory effect on the growth of G. lucidum, with an inhibition rate of up to 52.23%. High temperature, low temperature, light and other physical factors have no obvious inhibitory effect on this pathogen. Further investigation revealed that specific drugs, such as low concentrations (10 μL/mL) of Acticide DB20 and Imazalil, could effectively inhibit X. ganodermophthora growth in G. lucidum. Among them, Imazalil has a notable inhibitory effect on the growth of X. ganodermophthora.ConclusionsIndoor toxicity test and field control results showed that Imazalil could effectively control the growth of pathogen X. ganodermophthora in G. lucidum continuous cropping obstacle, and promote the growth of G. lucidum.Graphical

Neem (Azadirachta indica) seed extract formulation for managing anthracnose and gray mold diseases in strawberry

Anthracnose caused by Colletotrichum nymphaeae and gray mold caused by Botrytis cinerea are the most epidemic fungal diseases causing significantly losses in strawberry plantings. The objective of the study is to determine the antifungal activity of neem (Azadirachta indica A. Juss.) seed extracts and preparing new formulated antifungal agent. Plant extracts including alcoholic, aqueous and oil were extracted from neem seeds and used in concentrations of 1000, 2000, 4000, 8000 and 10,000 µl/l to control the vegetative mycelial growth of pathogens. The results showed that alcoholic extract had highest antifungal effect and used for the formulation. The concentration of 10,000 microliters of alcoholic extract showed 91.6 % inhibition of gray mold disease, while it inhibited 80.66 % in anthracnose disease and a significant difference was observed between them. For encapsulation of alcoholic neem extract with plant biopolymers with new changes, the separation method of water-miscible solvent through precipitation with salt was used. The results showed that the best effect of the formulation was observed at a dose of four per thousand. Inhibition at this concentration as the best option in terms of controlling gray mold and anthracnose disease was 86.3 % and 79.38 %, respectively, and they were placed in the same statistical group (d). This formulation is designed to determine the minimum concentration threshold and reduce the consumption of alcoholic extract. Based on the results, the use of formulated alcoholic extract of neem seed as an alternative to chemical fungicides can help control anthracnose and gray mold in strawberries.

Diallyl Trisulfide Acts as a Soil Disinfestation Against the Ilyonectria destructans through Inducing the Burst of Reactive Oxygen Species.

Soil-borne diseases represent an impediment to the sustainable development of agriculture. A soil-borne disease caused by Ilyonectria destructans severely impacts Panax species, and soil disinfestation has proven to be an effective management approach. Here, diallyl trisulfide (DATS), derived from garlic, exhibited pronounced inhibitory effects on the growth of I. destructans in vitro tests and contributed to the alleviation of soil-borne diseases in the field. A comprehensive analysis demonstrated that DATS inhibits the growth of I. destructans by activating detoxifying enzymes, such as GSTs, disrupting the equilibrium of redox reactions. A series of antioxidant amino acids were suppressed by DATS. Particularly noteworthy is the substantial depletion of glutathione by DATS, resulting in the accumulation of ROS, ultimately culminating in the inhibition of I. destructans growth. Briefly, DATS could effectively suppress soil-borne diseases by inhibiting pathogen growth through the activation of ROS, and it holds promise as a potential environmentally friendly soil disinfestation.

Research on the prevention and control of plant diseases by antagonistic microorganisms

Plant diseases, often caused by bacterial infections, pose significant challenges to human society due to their widespread and harmful consequences, resulting in substantial losses. Although traditional chemical prevention and control methods have shown effectiveness, they still pose serious environmental and other risks. Therefore, developing biological control is crucial for future plant disease prevention and management. In this study, we investigated the efficacy of antagonistic microorganisms. We conducted four related experiments and eventually reaffirmed the substantial inhibitory effect of antagonistic microorganisms on the growth of plant pathogens. Our findings are of great significance for further expanding the application scope and popularization of antagonistic bacteria and also enriching the specific application of antagonistic microorganisms for specific plant control.

Effect of Bio-Priming with Isolates of Fungal Bio Agents on Morphological Attributes and Growth Parameters of Chickpea

Chickpea (Cicer arietinum L.) is one of the most important pulse crops of India. Chickpea is one of the major and abundant sources of protein among pulses; production of chickpea is very low all over the worldwide due to several biotic and abiotic stresses. Biotic stress diseases are the major problems. Chickpea wilt caused by Fusarium oxysporum f. sp. ciceri has been considered as devastating one to cause up to 10 per cent loss in yield every year. For eco-friendly and sustainable management of the disease, six isolates of two fungal bioagents Trichoderma harzianum and Trichoderma viride were evaluated for their antagonistic efficacy on colony growth by dual culture plate method. The results showed that the bio-agents suppressed the colony growth ofpathogen which ranged between 70.80-59.29%. Isolates of T1 [Trichoderma harzianum (KN)] 70.80% was found very effective antagonistic effect compare to all treatments and control followed by T2 [Trichoderma harzianum (VN) which inhibited 68.80%, T3 [Trichoderma harzianum (UNN) 66.45% and T4 [T. viride (FBD)] 63.58% mycelia growth of pathogen and so on. The result of seed treatment in vivo condition showed that T1 found highest germination percent among all the treatments with a value of 85.71%. In all the treatment, substantially boosting the morphology of chickpea against control, the maximum number of branches was recorded in T1, with value of 12 and maximum root length was 13.33 cm with increase 81.85% over the control. In the yield parameter, the highest number of pods was found in T1 with 41 pods, followed by T2 and T3 with 37 and 36 pods, respectively. Result of the study show that bio-agents significantly reduced the wilt incidence, treated plants subsequently significantly increased germination percentage, morphological parameters and yield parameters over the non-treated plants. .

The Verticillium dahliae effector VdPHB1 promotes pathogenicity in cotton and interacts with the immune protein GhMC4.

Verticillium dahliae is a kind of pathogenic fungus that brings about wilt disease and great losses in cotton. The molecular mechanism of the effectors in V. dahliae regulating cotton immunity remains largely unknown. Here we identified an effector of V. dahliae, VdPHB1, whose gene expression is highly induced by infection. VdPHB1 protein is localized in the intercellular space of cotton plants. Knockout VdPHB1 gene in V. dahliae had no effect on pathogen growth, but decreased the virulence in cotton. VdPHB1 ectopically expressed Arabidopsis plants were growth-inhibited and significantly susceptible to V. dahliae. Further, VdPHB1 interacted with the type II metacaspase GhMC4. GhMC4 gene silenced cotton plants were more sensitive to V. dahliae with reduced expressions of pathogen defense-related and programmed cell death genes. The accumulation of GhMC4 protein were concurrently repressed when VdPHB1 protein expressed during infection. In summary, these results revealed a novel molecular mechanism of virulence regulation that the secreted effector VdPHB1 represses the activity of cysteine protease for helping V. dahliae infection in cotton.

Sustainable production of extracellular polymeric substances and iron or copper complex from glutinous rice processing wastewater

Essential trace minerals play vital roles in maintaining human and animal health. However, an overdose of the existing inorganic trace minerals is prone to induce detrimental effects that outweigh positive benefits. In this study, an extracellular polymeric substances (EPS)-producing bacterium, identified as Bacillus licheniformis CCTCC M2020298, was isolated from marine using glutinous rice processing wastewater as enrichment medium. The EPS yield of Bacillus licheniformis CCTCC M2020298 could reach 8.62 g/L by using glutinous rice-processing wastewater containing medium. Furthermore, the potential of the EPS as a carrier for synthesizing EPS-iron (Fe) and EPS-copper (Cu) complex was explored. The results showed that the optimum condition for the synthesis EPS-Fe were the reaction temperature 70°C, pH 8.5–9.0 and mass ratio of EPS to trisodium citrate 2:1. The iron content of EPS-Fe reached 77.4 mg/g. Under the same condition, the copper content of EPS-Cu reached 90.7 mg/g. The elemental composition, functional groups and valence state of the mineral elements of EPS-Fe and EPS-Cu were well characterized. The EPS-Fe and EPS-Cu exhibited antioxidant activity in scavenging ·OH, DPPH and ·O2− free radicals, thereby leading to reduced oxidative stress and apoptosis levels in human colonic epithelial cells in vitro. They also inhibited the proliferation of mouse hepatocellular carcinoma H22 and the growth of intestinal pathogens in vitro. This study provided an effective avenue for EPS production from glutinous rice processing wastewater and proved the potential of EPS-Fe and EPS-Cu complexes as a new-type comprehensive essential trace mineral supplement.

Evaluation for powdery mildew resistance in grapevine (Vitis venifere L.) parental germplasm under in-vitro and natural field conditions

Powdery mildew (PM) caused by Erysiphe necator Schwein [(syn. Uncinula necator (Schweinf.) Burrill.] is an ascomycete biotrophic fungus of grapevine, leading to substantial yield and economic losses in infected crop. Thirty-four genotypes of Vitis vinifera L., including commercial varieties and hybrids, two genotypes of V. champini, three interspecific hybrids of Vitis species and two wild indigenous Himalayan species, namely V. parviflora and V. jacquemontii were assessed for resistance to powdery mildew using the leaf disc method in-vitro with E. necator isolate and in the field under natural condition during 2022 and 2023. Significant differences in the scores among the grape genotypes were observed in both in-vitro and field conditions. Resistance evaluation under both conditions classified V. parviflora, 110R, Coudere 1613, Dogridge, St. George and V. vinifera cultivars like Male Hybrid, Pusa Navrang, Blank Prince and Merlot as resistant sources, which can serve as valuable donor parents for breeding programs. Correlation analysis illustrated the negative correlation between disease severity index (DSI) and temperature (r = -0.50 (max), r = -0.48 (min)), rainfall (r = -0.07) and a positive correlation with relative humidity (r = 0.42). In-vitro inoculation, Organisation Internationale de la Vigne et du Vin Descriptors (OIV) scores (7 days post inoculation (dpi)) showed a negative correlation with hyphal area percentage (r = -0.90) and a positive correlation with necrosis (r = 0.86) indicating the resistant genotypes showing necrosis at the infection site and thus restricted the pathogen growth

Frequency and antimicrobial susceptibility profile of Methicillin-resistant Staphylococcus aureus isolated from Pus and Swab samples in a Teaching Hospital of Lahore

Background: Staphylococcus is a ubiquitous bacterium and well-known pathogen causing a variety of infections. The global spread of MRSA constitutes one of the most prevailing challenges to the management of infections caused by this bug.
 Aim: To determine the frequency of MRSA and antibiogram profile of S. aureus recovered from various clinical samples.
 Setting: Microbiology Laboratory of Shalamar Hospital Lahore.
 Methods: The data of the Staphylococcus isolates including MRSA from various pus and swab samples was collected through Electronic Medical Record of the Shalamar Hospital from 1st Jan to 31st Dec 2021. S. aureus was identified by standard protocol including Gram stain, catalase, coagulase, and DNase tests. Antimicrobial susceptibility was carried out by modified Kirby Bauer method. MRSA frequency was determined by the result of sensitivity to cefoxitin.
 Results: Out of 885 samples submitted for culture, 517 (58.4%) were reported for microbial growth of a known pathogen. The most frequently isolated pathogen was S. aureus (37.9%), followed by E. coli (22.4%), other members of Enterobacteriaceae family (17.8%), Pseudomonas (15.5%), Enterococcus (3.5%), Candida (2.1%), and Streptococcus (0.8%). Amongst S. aureus, MRSA was documented in 46.9% cases. Substantial difference was detected in the susceptibility pattern of methicillin-sensitive and resistant staphylococci. All staphylococci were resistant to ampicillin while no vancomycin resistance was encountered.
 Conclusion: MRSA was seen in the local population with a high frequency of 46.9% and such MRSA also showed marked resistance against other commonly used antibiotics. Fortunately no vancomycin-resistant S. aureus was reported.

Assessment of different control means to protect grape berries from biotic injuries in postharvest

To find alternatives similar in effectiveness to conventional fungicides, two commercial disease resistance inducers, EP5-Protect (Phenom Biotech, Milan Italy; EP) and BioDea Flavor (BioDea, Arezzo, Italy; WD), and bioactive extracts (BCEs) from a strain of Streptomyces albidoflavus (CARA17), were compared to the fungicide fludioxonil in in vitro and in vivo trials to control postharvest decay on table grapes by Botrytis cinerea and Monilinia laxa. Disease severity and incidence were recorded by Mckinney index values of 0.0–5.0. On culture media, EP, BCEs, and fludioxonil significantly inhibited the growth of both pathogens by 100% for B. cinerea, and 79–100% for M. laxa, while WD inhibited both pathogens by 15–25%. Similar results were obtained from experimental trials with inoculated grape berries treated with these compounds after harvest. Fludioxonil was the most effective treatment to control both pathogens applied to uninoculated or inoculated grapes. EP was significantly but moderately effective to control both pathogens and the other saprophytic microorganisms, whereas the effectiveness of BCEs from S. albidoflavus was significantly less, and WD was the least effective treatment. Our results indicate EP and BCEs may be promising to control postharvest decay on grapes and other fresh products. They could conceivably be used to replace sulfur dioxide fumigation currently used to protect grapes after harvest, in particular when storage is not prolonged.

Rhizospheric microbiota of suppressive soil protect plants against Fusarium solani infection.

Fusarium infection has caused huge economic losses in many crops. The study aimed to compare the microbial community of suppressive and conducive soils and relate to the reduction of Fusarium wilt. High-throughput sequencing and microbial network analysis were used to investigate the differences in the rhizosphere microbiota of the suppressive and conducive soils and to identify the beneficial keystone taxa. Plant pathogens were enriched in the conducive soil. Potential plant-beneficial microorganisms and antagonistic microorganisms were enriched in the suppressive soil. More positive interactions and keystone taxa existed in the suppressive soil network. Thirty-nine and 16 keystone taxa were identified in the suppressive and conducive soil networks, respectively. Sixteen fungal strains and 168 bacterial strains were isolated from suppressive soil, some of which exhibited plant growth-promotion traits. Thirty-nine bacterial strains and 10 fungal strains showed antagonistic activity against F. solani. Keystone taxa Bacillus and Trichoderma exhibited high antifungal activity. Lipopeptides produced by Bacillus sp. RB150 and chitinase from Trichoderma spp. inhibited the growth of F. solani. Microbial consortium I (Bacillus sp. RB150, Pseudomonas sp. RB70 and Trichoderma asperellum RF10) and II (Bacillus sp. RB196, Bacillus sp. RB150 and T. asperellum RF10) effectively controlled root rot disease, the spore number of F. solani was reduced by 94.2% and 83.3%. Rhizospheric microbiota of suppressive soil protects plants against F. solani infection. Antagonistic microorganisms in suppressive soil inhibit pathogen growth and infection. Microbial consortia consisted of keystone taxa well control root rot disease. These findings help control Fusarium wilt. © 2024 Society of Chemical Industry.

Evaluation of phytoconstituents in marigold effluent for their antifungal activity against plant pathogens.

The current study placed an intense emphasis on the excess discharge of agro-based industrial effluent and the use of plant extract antimicrobials to inhibit the growth of pathogens in crop plants. An effluent (treated and untreated) from the marigold flower processing industry has been identified for the presence of volatile and semi-volatile organic compounds, and a total of 18 in treated effluent and 23 in untreated effluent were found using gas chromatography-mass spectrometry. A total of 13 classes were identified, which include carboxylic acid, phenols, esters, alkanes, alkenes, alcohols, cyanide, heterocyclic, flavonoids, aldehydes, polycyclic aromatic, cycloalkanes, and cycloalkenes. A principal component analysis with varimax rotation was applied to discern the abundance of identified compounds under each class. An in vitro antifungal bioassay was conducted using effluents at three different concentrations against plant pathogens (Alternaria alter nata, Sclerotium rolfsii, Rhizoctonia solani, Pythium aphanidermata, Fusarium oxysporum, and Colletotrichum gloeosporioides). The study proved that treated and untreated effluents clearly inhibited the growth of fungal pathogens by 10 to 32% and 37 to 92%, respectively. The findings suggest that marigold flower effluent can be a promising resource for developing new plant protection methods that are effective against pathogenic fungi.

Biological control effect of Trichoderma harzianum (Hypocreales: Hypocreaceae) against phytopathogens

AbstractChemical pesticides are synthetic substances created to manage plant pests. Frequent chemical usage causes extensive damage to crops and contributes to pest resistance, leading to environmental contamination, harm to non‐target organisms, the emergence of pesticide‐resistant species, and potential health hazards for humans. The aim of this study is to isolate, identify, and characterize biocontrol agents Trichoderma harzianum and evaluate their effects on various plant phytopathogens. T. harzianum biocontrol effects were tested against various fungal phytopathogens, including Sclerotium rolfsii, Alternaria sp., Pythium aphanidermatum, Macrophomina phaseolina, Fusarium oxysporum, Helminthosporium sativum, and Aspergillus niger. The results clearly showed that, compared to the other Trichoderma species, TVK1 demonstrated the highest ability to suppress phytopathogens, with a growth inhibition rate of 2.48 cm per day. TVK2 grows at a rate of 1.96 cm per day, whereas TVK5 grows at a rate of 1.98 cm per day. The level of antifungal volatile organic compounds produced by TVK1 spores was higher against plant pathogens compared to the other species examined. This compound inhibits the growth of plant pathogens. T. harzianum can eliminate 100% of S. rolfsii pathogens and 100% of Alternaria sp. Pathogens were reduced by 92.02% for A. niger, 94% for F. oxysporum, 100% for P. aphanidermatum, 94.07% for H. sativum, and 100% for M. phaseolina. In a detached leaf assay, TVK1 inhibited the growth of pathogens in various plant leaves, including tomato, mustard, and eggplant, when compared to both the commercially available fungicide and the control. The study confirms that the isolate TVK1 can combat various phytopathogens. Early application of T. harzianum can reduce the risk of phytopathogenic attacks on leaves and promote plant growth.

Unlocking the genetic potential of Lacticaseibacillus rhamnosus strains: Medical applications of a promising probiotic for human and animal health

Lacticaseibacillus rhamnosus is a group of probiotic strains that have gained popularity for their potential health benefits such as promoting digestive health, boosting the immune system, improving lactose digestion, preventing and treating antibiotic-associated diarrhea, reducing the severity and duration of certain infections, and preventing the formation of dental plaque. In particular, L. rhamnosus strains SD4 and SD11 have promising human and animal health applications due to their ability to inhibit the growth of harmful pathogens. This study presents an in silico genomic analysis of L. rhamnosus strains SD4 and SD11. We analyzed draft genomes and conducted comparative genome analyses against several other probiotic strains, aiming to gain insights into the genomes of the two strains and to compare them to related strains isolated from other sources. We also aimed to clarify the functional mechanisms and adaptation of these strains to specific environments. Comprehensive insights into the genomes of L. rhamnosus SD4 and SD11 could enhance our understanding of their capacity to colonize, adapt, and exhibit probiotic properties after administration. This study holds significance in advancing our understanding of the potential health benefits associated with these strains and in elucidating the underlying mechanisms responsible for their effectiveness in humans and animals.

Antibacterial effects of chitosan-based hydrogels containing Trachyspermum ammi essential oil on pathogens isolated from dogs with otitis externa

BackgroundGrowing antibiotic resistance has made treating otitis externa (OE) increasingly challenging. On the other hand, local antimicrobial treatments, especially those that combine essential oils (EOs) with nanoparticles, tend to be preferred over systemic ones. It was investigated whether Ajwain (Trachyspermum ammi) EO, combined with chitosan nanoparticles modified by cholesterol, could inhibit the growth of bacterial pathogens isolated from OE cases in dogs. In total, 57 dogs with clinical signs of OE were examined and bacteriologically tested. Hydrogels of Chitosan were synthesized by self-assembly and investigated. EO was extracted (Clevenger machine), and its ingredients were checked (GC-MS analysis) and encapsulated in chitosan-cholesterol nanoparticles. Disc-diffusion and broth Micro-dilution (MIC and MBC) examined its antimicrobial and therapeutic properties.ResultsStaphylococcus pseudintermedius (49.3%) was the most common bacteria isolated from OE cases, followed by Pseudomonas aeruginosa (14.7%), Escherichia coli (13.3%), Streptococcus canis (9.3%), Corynebacterium auriscanis (6.7%), Klebsiella pneumoniae (2.7%), Proteus mirabilis (2.7%), and Bacillus cereus (1.3%). The investigation into the antimicrobial properties of Ajwain EO encapsulated in chitosan nanoparticles revealed that it exhibited a more pronounced antimicrobial effect against the pathogens responsible for OE.ConclusionsUsing chitosan nanoparticles encapsulated with EO presents an effective treatment approach for dogs with OE that conventional antimicrobial treatments have not cured. This approach not only enhances antibacterial effects but also reduces the required dosage of antimicrobials, potentially preventing the emergence of antimicrobial resistance.

Biochemically Characterization of Clinically Impactful Bacteria in Baby Food Items Along with their Drug Susceptibility Pattern

Abstract BACKGROUND: Millions of babies worldwide are fed powdered formula and ready-to-eat baby food from birth during the first 2 years of life. The high nutritional content of such food items makes them an excellent growth medium for the growth of potential foodborne pathogens. METHODS: Considering the child health/public health matter, the present study attempted to evaluate the microbiological quality of commonly consumed baby food items along with their drug susceptibility pattern of the isolated bacteria through conventional and cultural methods as well as Kirby–Bauer methods, respectively. RESULTS: The investigation revealed that all samples were found to be contaminated with heterotrophic bacteria within the range of 103–105 CFU/g, particularly formula milk and optimal milk showed maximum contamination up to 106 CFU/g. Pseudomonas spp. displayed significantly high growth in all samples, whereas Staphylococcus spp. was identified in oats, formula milk, and optimal milk. Bacillus spp. was found in cerelac, apple Puree, formula milk, and optimal milk. Notably, Salmonella spp. was absent in all samples. In addition, Vibrio spp. was estimated in formula milk up to 102 CFU/g. Meanwhile, Shigella spp. was detected in formula milk and optimal milk. Most of the isolates exhibited resistance against a wide range of antibiotics. Only STR (10 μg), GEN (10 μg), AZM (15 μg), and NA (5 μg) exhibited the efficacy against the bacterial growth. CONCLUSION: These findings underscore the importance of strict hygiene and safety practices in the food industry to mitigate the health risks associated with microbial contamination in baby foods. Furthermore, prudent antibiotic use is crucial to combat emerging resistance and ensure the safety of these products for consumers.

Antifungal Activity-Guided Analysis of Actinostemma lobatum Extracts through Serial Sub-fractions.

Plants are treasure trove of novel compounds that have potential for antifungal chemicals and drugs. In our previous study, we had screened plant extracts obtained from more than eight hundred plant materials collected in Korea, and found that butanol fraction of the Actinostemma lobatum were most potent in suppressing growth of diverse fungal pathogens of plants. Here in this study, we describe further analysis of the butanol fraction, and summarize the results of subsequent antifungal activity test for the sub-fractions against a selected set of plant pathogenic fungi. This line of analyses allowed us to identify the sub-fractions that could account for a significant proportion of observed antifungal activity of initial butanol fraction from A. lobatum. Further analysis of these sub-fractions and determination of structure would provide the shortlist for novel compounds that can be a lead to new agrochemicals.

Antagonistic potential of soil fungi as biocontrol agent against rice pathogens

Antagonistic potential of six soil fungi viz., Aspergillus flavus Link., A. fumigatus Fresen., A. niger Tiegh., Penicillium sp., Trichoderma harzianum Refat. and T. viride Pers. against eight pathogenic fungi viz., Alternaria alternata (Fr.) Keissler, Curvularia lunata (Wakker) Boedijn, Drechslera oryzae Breda de Haan (Subramanian and Jain), Fusarium moniliforme Sheldon, F. solani (Mart.) Sacc. Microdochium oryzae (Hashloka and Yokogi) Sam. and Hal., Pestalotiopsis guepinii (Desm.) Stay. and Sarocladium oryzae (Sawada) W. Gams and D. Hawks of rice were evaluated. In colony interaction, the highest growth inhibition (88%) was observed owing to T. harzianum against Alternaria alternata.Volatile substances from soil fungi inhibited the radial growth of the test pathogens which varied from 8.33 to 57.36%.The highest inhibition (57.36%) was found owing to T. harzianum against P. guepinii. The inhibition of mycelial growth of the test pathogens ranged from 29.05 to 64.5% owing to non volatile substances of the soil fungi. The highest mycelial growth inhibition was observed owing to T. harzianum against C. lunata. Trichoderma harzianum may be exploited commercially to control rice pathogens. Bangladesh J. Bot. 53(1): 101-108, 2024 (March)