Pantoea Agglomerans Research Articles

Stigmas of holoparasitic Phelipanche arenaria (Orobanchaceae) – a suitable ephemeric flower habitat for development unique microbiome

BackgroundMicrobial communities have occasionally been observed in part of the ephemeric reproductive structure of floral stigmas, but their prevalence, phylogenetic diversity and ecological roles are understudied. This report describes the first study of bacterial and fungal communities in immature and mature stigma tissue of the endangered holoparasitic plant Phelipanche arenaria. Culture-dependent methods coupled with next-generation sequencing indicated that a small surface of the flower stigma was an unexpectedly rich and diverse microhabitat for colonization of microbial. We also compared the enzymatic activity of the bacterial communities between immature and mature stigmas samples.ResultsUsing high-throughput sequencing methods, we identified and classified 39 to over 51 OTUs per sample for bacterial OTUs represented by Pantoea agglomerans and P. ananatis, comprising 50.6%, followed by Pseudomonas, Luteibacter spp., Sphingomonas spp. with 17% of total frequency. The bacterial profile of immature stigmas of P. arenaria contained unique microorganisms (21 of the most numerous OTUs) that were not confirmed in mature stigmas. However, the enzymatic activity of bacteria in mature stigmas of P. arenaria showed more activity than observed in immature stigmas. In the fungal profile, we recorded even 80 OTUs in mature stigmas, consisting of Capnodiales 45.03% of the total abundance with 28.27% of frequency was created by Alternaria eichhorniae (10.55%), Mycosphaerella tassiana (9.69%), and Aureobasidium pullulans (8.03%). Additionally, numerous putative plant growth-promoting bacteria, fungal pathogens and pathogen-antagonistic yeasts were also detected.ConclusionsOur study uncovered that P. arenaria stigmas host diverse bacterial and fungal communities. These microorganisms are well known and have been described as beneficial for biotechnological and environmental applications (e.g., production of different enzymes and antimicrobial compounds). This research provided valuable insight into the parasitic plant–microbe interactions.

Prevalence of Pathogenic Enterobacteria in Market Garden Produce Grown in the Peri-Urban Area of Abidjan, Ivory Coast

This study, which is a contribution to national health surveillance of pathogens, was conducted to determine the prevalence of pathogenic Enterobacteriaceae in the market garden environment of Abidjan. To this end, samples of lettuce, irrigation water, manure and soil were taken from three (03) major market gardening sites in Abidjan. Microbiological analyses of these samples were carried out. The enterobacteria obtained after isolation were identified. The results revealed ten (10) bacterial genera belonging to the Enterobacteriaceae family, including 15 bacterial species in the samples of lettuce, irrigation water, manure and soil analysed. These included Salmonella enterica with serotypes (Salmonella Gallinarum, Salmonella Arizonae, Salmonella Choleraesus), Salmonella spp, Escherichia coli, Shigella boydii, Shigella sonnei, Enterobacter cloacae, Enterobacter aerogenes, Enterobacter gergoviae, Enterobacter agglomerans, Serratia marcesens, Serratia phymutica, Afnia alvei, Citrobacter freuidii Citrobacter diversus, Providencia alcalifasciens, Proteus vulgaris and Yersinia spp. The presence of these pathogenic Enterobacteriaceae indicates a potential risk associated with the consumption of lettuce produced in Abidjan. The Ivorian authorities should take preventive measures, such as educating market gardeners about the harmful effects of contaminated water used to irrigate vegetables, and the use of animal droppings as fertiliser to fertilise the soil, to avoid the future proliferation of infectious diseases such as typhoid fever and bacillary dysentery among the population of Abidjan.

Bacterial contamination of multi-use tear drops, gels, and ointments

PurposeThis study aimed to investigate the bacterial contamination of multi-use tear drops, gels, and ointments that patients use at home. MethodA total of 271 multi-use containers used by 168 patients were examined. Conjunctival culture samples were obtained from patients who used tear drops, gels, and ointments that were found to be contaminated. ResultsBacterial contamination was detected in 33 (12.2 %) out of the 271 containers. The contamination rate was 7.9 % in tear drops, 11.7 % in gels, and 32 % in ointments. A statistically significant difference was found between the drops, gels, and ointment groups (P = 0.04). Bacterial contamination was detected in 25 (18.9 %) out of 132 collapsible tubes and 8 (5.8 %) out of 139 plastic bottles (P = 0.01). Important bacteria, including Pseudomonas stutzeri, Pseudomonas aeruginosa, Bacillus licheniformis, Paenibacillus pabuli, Proteus mirabilis, Pantoea agglomerans, Morganella morganii, Serratia marcescens, and Serratia liquefaciens, were detected. Mucorales spp. fungus was seen in a gel. Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus, and M. morganii were found in the conjunctival microbiota of three patients. ConclusionThe overall contamination rate of ocular lubricants was low (12.2%); however, a significant difference was found between the drops, gels, and ointments. The contamination rate was higher in gels and ointments than that in drops. The contamination rate was found to be increased in the collapsible tube. The use of ocular lubricants is safe; however, patients must be cautious when using multi-use tear drops, gels, and ointments to avoid contamination. Whenever possible, bottles should be preferred instead of collapsible tubes.

Use of Pantoea agglomerans ASB05 as a biocontrol agent to inhibit the growth of Salmonella enterica on intact cantaloupe melons.

To identify biocontrol agents to prevent the growth of Salmonella serotype Enterica on cantaloupe melons during the pre- and postharvest periods. We created a produce-associated bacterial library containing 8736 isolates and screened it using an in-vitro fluorescence inhibition assay to identify bacteria that inhibit the growth of S. Enterica. One isolate, Pantoea agglomerans ASB05, was able to grow, persist, and inhibit the growth of S. Enterica on intact cantaloupe melons under simulated pre- and postharvest conditions. We also demonstrated that the growth inhibition of S. Enterica by P. agglomerans ASB05 was due to the production of a phenazine type antibiotic. Pantoea agglomerans ASB05 is an effective biocontrol agent for the prevention of S. Enterica growth on intact cantaloupe melons in both the pre- and postharvest environments.

Biodegradation of Choline NTF2 by Pantoea agglomerans in Different Osmolarity. Characterization and Environmental Implications of the Produced Exopolysaccharide.

A specific microorganism, Pantoea agglomerans uam8, was isolated from the ionic liquid (IL) Choline NTF2 and identified by molecular biology. A biodegradation study was performed at osmolarity conditions (0.2, 0.6, 1.0 M). These had an important influence on the growth of the strain, exopolysaccharide (EPS) production, and biodegradation (1303 mg/L max production and 80% biodegradation at 0.6 M). These conditions also had an important influence on the morphology of the strain and its EPSs, but not in the chemical composition. The EPS (glucose, mannose and galactose (6:0.5:2)) produced at 0.6 M was further characterized using different techniques. The obtained EPSs presented important differences in the behavior of the emulsifying activity for vegetable oils (olive (86%), sunflower (56%) and coconut (90%)) and hydrocarbons (diesel (62%), hexane (60%)), and were compared with commercial emulsifiers. The EPS produced at 0.6 M had the highest emulsifying activity overall. This EPS did not show cytotoxicity against the tested cell line (<20%) and presented great advantages as an antioxidant (1,1-diphenyl-2-picryl-hydrazyl radical (DPPH) (85%), hydroxyl radical (OH) (99%), superoxide anion (O2-) (94%), chelator (54%), and antimicrobial product (15 mm). The osmolarity conditions directly affected the capacity of the strain to biodegrade IL and the subsequently produced EPS. Furthermore, the EPS produced at 0.6 M has potential for environmental applications, such as the removal of hazardous materials by emulsification, whilst resulting in positive health effects such as antioxidant activity and non-toxicity.

Heterologous Production in the Synechocystis Chassis Suggests the Biosynthetic Pathway of Astaxanthin in Cyanobacteria.

Astaxanthin is a carotenoid species with the highest antioxidant capability. Its natural resource is very rare. The biosynthesis of astaxanthin from β-carotene includes a hydroxylation step and a ketolation step, for which the corresponding enzymes have been characterized in a few species. However, the sequence of these two reactions is unclear, and may vary with different organisms. In this study, we aimed to elucidate this sequence in Synechocystis, which is an ideal cyanobacterial synthetic biology chassis. We first silenced the endogenous carotene oxygenase gene SyneCrtO to avoid its possible interference in the carotenoid metabolic network. We then introduced the β-carotene ketolase gene from Haematococcus pluvialis (HpBKT) and the CrtZ-type carotene β-hydroxylase gene from Pantoea agglomerans (PaCrtZ) to this δCrtO strain. Our pigment analysis demonstrated that both the endogenous CrtR-type carotene hydroxylase SyneCrtR and HpBKT have the preference to use β-carotene as their substrate for hydroxylation and ketolation reactions to produce zeaxanthin and canthaxanthin, respectively. However, the endogenous SyneCrtR is not able to further catalyze the 3,3'-hydroxylation of canthaxanthin to generate astaxanthin. From our results, a higher accumulation of canthaxanthin and a much lower level of astaxanthin, as confirmed using liquid chromatography-tandem mass spectrometry analysis, were detected in our transgenic BKT+/CrtZ+/δCrtO cells. Therefore, we proposed that the bottleneck for the heterologous production of astaxanthin in Synechocystis might exist at the hydroxylation step, which requires a comprehensive screening or genetic engineering for the corresponding carotene hydroxylase to enable the industrial production of astaxanthin.

Pantoea agglomerans: A rare infectious outbreak affecting maintenance hemodialysis patients in a tertiary care hospital.

Pantoea agglomerans is an environmental pathogen known to cause infection in immunocompromised individuals, particularly after thorn injuries. However, previous data showed few cases of human disease caused by contaminated medical products such as parenteral nutrition, anesthetic agents, blood, and peritoneal dialysis solutions. Infection in hemodialysis patients is rare. In this study, we presented a detailed account of several hemodialysis patients infected with this contagious pathogen and compared them with noninfected dialysis patients. We retrospectively reviewed the hospital records of 105 hemodialysis patients. Seventeen of 105 patients were diagnosed with P. agglomerans infection. We carefully analyzed their entire in-hospital course. Among infected patients, 52.9% were male with a median age of 49 (IQR: 32-66) years. Compared to the noninfected patients, age below 50 years, prior kidney transplantation, prior immunosuppression and antibiotics use, and dialysis via a tunneled vascular catheter were the significant epidemiological features. Despite negative microbiological investigations, we suspect the possible infectious spread via infected central venous catheter was the likely infectious source. Most importantly, all patients responded well to intravenous antibiotics. Only two patients required the removal of the tunneled catheter. Their mortality rate was 0%. P. agglomerans infection, although considered rare, is becoming increasingly prevalent among dialysis patients. Its occurrence must be appraised as an infectious outbreak rather than mere contamination. Prompt treatment, source identification, and early implementation of preventive strategies should always be the goal to curtail this infection at an early stage.

The ability of two indigenous bacteria isolated from Moroccan olive tree to promote the growth of olive seedlings in the presence of the pathogen Verticillium dahliae

ABSTRACT The rhizosphere of olive trees (Olea europaea L.) is a source of bacteria with a high potential for biocontrol and plant growth promotion. In the present study, two native olive tree gram-negative bacteria were isolated from the rhizosphere of century-old trees in the region of Zouala (south-eastern Morocco), known for its arid climate and saline soils. The strains Pantoea agglomerans and Enterobacter ludwigii exhibited high tolerance to high PEG and NaCl concentrations, and significant plant growth-promoting (PGP) potential in vitro. The two strains efficiently solubilised phosphate in its two forms (TCP and RP), and Mica as a source of potassium and produced IAA. The two strains exhibited in vitro inhibition ability against Verticillium dahliae with partial inhibition of the growth of the mycelium by the strain P. agglomerans MRC_ZO_17. Greenhouse experiments showed that olive tree seedlings treated with the E. ludwigii MRC_ZO_97 strain significantly improved growth (dry weight) in the presence and absence of the pathogen compared to untreated plants, while the P. agglomerans MRC_ZO_17 strain showed significant effects on seedling growth only in the presence of the pathogen V. dahliae OV1 defoliating pathotype. Both strains showed high exopolysaccharides (EPS) production and good biofilm formation, making them excellent plant growth-promoting rhizobacteria (PGPRs) and Biological Control Agents (BCAs) with great potential to survive in soil under stress conditions.

Evaluation of the fermentation performance and functional properties of bacterial communities of amaranth silage supplemented with Limosilactobacillus fermentum and Latilactobacillus graminis

BackgroundThe objective was to determine the effects of different lactic acid bacteria (LAB) on amaranth (Amaranthus hypochondriaus) silage fermentation characteristics, changes in bacterial communities and their functional properties, and to investigate the preferential effects and mechanisms of action of Limosilactobacillus fermentum (L. fermentum) and Latilactobacillus graminis (L. graminis) on the bacterial communities of silage. LAB were screened and identified from native grasses and its naturally fermented silage, and their effects on fermentation performance and bacterial community of amaranth after 60 days of fermentation were investigated. BL1 and BL5 strains were identified as L. fermentum and L. graminis, respectively. They could grow normally at concentrations of 3.0% and 6.5% NaCl, tolerating pH and temperature ranges of 3.5 –9.0 and 4.0 – 9.0, 30 – 45 ℃ and 10 – 45 ℃, respectively. The distilled water, Lactiplantibacillus plantarum (commercial inoculant), L. fermentum, and L. graminis were inoculated into amaranth at a total of 1 × 105 cfu/g fresh material and labeled AhSCK, AhSLP, AhSLF, and AhSLG, respectively, while the fresh amaranth was labeled YLS.ResultsAs expected, the water soluble carbohydrates of AhSCK was lower than AhSLG (p < 0.05). The highest number of LAB was found in AhSLF (p < 0.05). The lactic acid (LA) content of AhSLP was significantly higher (p < 0.05) than other silage. Nevertheless, acetic acid (AA) content of AhSLF was significantly different from other silage (p < 0.05). All the amaranth silage was well preserved with low pH (4.16 – 4.51) and acceptable levels of butyric acid (0.00 – 0.86%FM). At the species level, Pantoea agglomerans, Pseudomonas oryzihabitans, and Cenchrus americanus served as the dominant strains in fresh amaranth, with relative abundances lower than 1% after ensiling.. Lentilactobacillus buchneri, Levilactobacillus brevis, and L. fermentum were the dominant strains of AhSCK, AhSLP and AhSLF. Nevertheless, the predominant strains of AhSLG was Xanthomonas oryzae. Both fresh material and silage, L. fermentum, L. plantarum, Levilactobacillus brevis, Pantoea agglomerans, Pseudomonas oryzihabitans, Cenchrus americanus, Pseudomonas coleopterorum, Priestia aryabhattai, and Exiguobacterium sibiricum were significantly different in relative abundance (p < 0.01).Functional prediction analysis showed that in pyruvate metabolism, glycolysis/gluconeogenesis and amino sugar and nucleotide sugar metabolism were enriched after ensiling. AhSLF showed the most obvious trend of increasing abundance of pentose phosphate pathway, biosynthesis of secondary metabolites and biosynthesis of antibiotics, while the abundance of metabolic pathways decreased significantly (p < 0.05).ConclusionsL. fermentum can be recommended as an additive to improve the quality of amaranth silage, as it regulates the epiphytic microbiota in silage, improving the fermentation quality and metabolic capacity of the bacterial community.Graphical

Analysis of key genes for the survival of Pantoea agglomerans under nutritional stress

The absolute amount of nutrients on plant leaves is usually low, and the growth of epiphytic bacteria is typically limited by nutrient content. Thus, is of great significance to study the survival mechanism of epiphytes under nutritional stress for plant disease control. In this paper, Pantoea agglomerans CHTF15 isolated from walnut leaves was used to detect the key genes for the survival of the bacterium under simulated nutrient stress in artificial medium. Genome sequencing was combined with transposon insertion sequencing (Tn-seq) for the detection technique. A total of 105 essential genes were screened from the whole genome. The genes were mainly related to the nucleotide metabolism, protein metabolism, biological oxidation and the gene repair of bacteria analyzed by gene ontology (GO) enrichment analysis. Volcano map analysis demonstrated that the functions of the 15 genes with the most significant differences were generally related to the synthesis of amino acids or proteins, the nucleotide metabolism and homologous recombination and repair. Competitive index analysis revealed that the deletion of the genes dksA and epmA regulating protein synthesis, the gene ribB involved in the nucleotide metabolism and the gene xerD involved in recombination repair induced a significant reduction in the survival ability of the corresponding mutants in the 0.10 % YEP medium and the walnut leaf surface. The results act as a foundation for further in-depth research on the infection process and the mechanisms of pathogenic bacteria.

A Review Articles: Pantoea agglomerans in UTI- It is Bacteria Caused Urinary Tract Infection and Genomic Analysis related with Bacterial Resistance

Pantoea Spp. is a plant bacteria that has been identified as an emerging pathogen in humans related with outbreaks and many clinical infections. It is referred to as a "mystery bacterium of evil and good" since it may cause both bad and good. With the proposed investigation, the researchers hope to uncover a significant risk component that is connected with reoccurring urinary tract infections (UTI). They also hope to identify bacterial reasons and antibiotic susceptibility profiles that can be used to lower the threat of reinfection and prevent complications associated with recurrent UTI. In the existence of risk variables, the likelihood of developing a UTI increases; also, a correct susceptibility pattern increases the likelihood of achieving therapeutic effectiveness and preventing illness complications. Because of its capacity to infect immunocompromised persons and produce severe illness as a consequence of its multi - drug resistance, Pantoeasppregard is considered to be a dangerous opportunistic pathogen. In this paper we are going to focus on related bacteria, pathogenicity, resistance genes, classification.

Heavy-metal tolerant bacterial strains isolated from industrial sites and scrap yards in Kashmir, India.

Heavy metal pollution has posed a severe danger to environmental stability due to its high toxicity and lack of biodegradability. The present study deals with the appraisement of tolerance shown by various bacteria in varied copper and iron concentrations. Among the 20 isolates, four isolates, GN2, SC5, SC8, and SC10, exhibiting more significant iron and copper tolerance, were selected and identified by 16 S ribosomal ribonucleic acid (rRNA) gene sequence analysis as Pantoea agglomerans strain GN2, Pantoea sp. strain SC5, Bacillus sp. strain SC8 and Priestia aryabhattaistrain SC10. The minimum inhibitory concentration of molecularly identified strains revealed that P. agglomerans strain GN2 showed tolerance to iron sulfate and copper sulfate upto 600 and 400 µg/mL, whereas Bacillus sp. SC8 (OQ202165) showed tolerance of 700 and 250 µg/mL were tolerant to iron sulfate and copper sulfate up to 700 and 150 µg/mL, respectively. Pantoea sp. strain SC5 showed significant tolerance to both heavy metals. The isolates were further studied for their ability to grow at varying temperatures and pH ranges. Most of the isolates showed optimal growth at 37°C and pH 7. However, Pantoea sp. SC5 was competent to have prominent growth at 45°C and pH 8.0. Microbial remediation, which is eco-friendly, has proven the most effective method for bioremediation of heavy metal-contaminated environments. Using heavy metal-resistant bacteria for microbial remediation of iron and copper-contaminated environments could be a viable and valuable strategy. These isolates could also be used to decontaminate heavy metal-polluted agricultural soils.

A replica plating method for efficient, high-throughput screening of antibiotic gene clusters in bacteria uncovers a holomycin-like cluster in the clinical isolate, Pantoea agglomerans 20KB447973

Bacterial natural products remain a major untapped source for novel antimicrobial scaffolds. Many of these products are encoded by biosynthetic gene clusters (BGCs), which can be identified using functional genomics. We developed a replica-plating approach to quickly screen for antibiotic production mutants from transposon mutant libraries and identify candidate antibiotic BGCs. In this technique, filter paper is used to transfer up to 200 mutants simultaneously onto a soft agar overlay or spread plate containing a target microbe to identify antibiotic-production mutants. These mutants can then be analyzed to identify disrupted genes and antibiotic BGCs. We first tested and optimized this technique by screening for previously characterized BGCs in Pantoea. We then applied the technique to uncover the gene cluster responsible for the production of an unknown broad-spectrum antibiotic from P. agglomerans 20KB447973, which we call Pantoea Natural Product 5 (PNP-5). Analysis of the predicted gene cluster for PNP-5 showed similarity to previously identified gene clusters for the broad-spectrum dithiolopyrrolone antibiotic, holomycin. Analysis of the spectrum of activity of PNP-5 showed activity against members of the Enterobacteriaceae, Erwiniaceae, and Streptococcaceae, including clinically relevant pathogens such as Klebsiella sp. and Escherichia coli. We also identified the production of a second antibiotic, pantocin A. Our findings demonstrate the utility of our replica-plating mutant transfer method in exploring unknown antibiotic BGCs. Adoption of this technique may accelerate the identification of potentially novel antimicrobial BGCs within strain collections, advancing the search for novel antimicrobials that can be used to treat multi-drug resistant infections.

First Report of Pantoea agglomerans Causing a Leaf Blight and Bulb Rot of Onion in Chile.

Onion (Allium cepa L) is an important vegetable crop in Chile with 3.675 ha (ODEPA, www.odepa.gob.cl). Since 2017, a series of symptoms has been increasingly observed, mainly in mature bulbs which include water-soaked lesions on mature leaves and external and central cataphylls, which evolve to necrotic lesions and rot, reducing yields and affecting the postharvest life. As the season progresses over 90% incidence has been estimated in severely affected fields. Symptomatic plants were collected for disease identification in summer (February 2022) in Santa Cruz, O´Higgins, Chile, (34º41'32"S and 71º27'17"W). Isolations were done on semi-selective OEM medium (Zaid et al. 2012) and isolated colonies were transferred and maintained on King's B (KB) medium. Colonies on OEM medium were yellow slightly green in the center, circular to irregular shape, elevated, smooth margin, and mucoid texture (Tho et al. 2015). On KB medium colonies were yellow cream, slightly darker in the center, with smooth margins and circular or slightly irregular. Two isolates (CHS B3, CHS B1), obtaining in three different onion fields, were further identified by PCR amplification of partial 16S rRNA using primers 27F/1492R (Frank et al., 2008). The resulting sequencing were deposited in GenBank under accession numbers OP934962.1 and OP934961.1. A BLAST search of GenBank showed that these sequences exhibited 99,89 to 100 % nucleotides similarities with multiple Pantoea agglomerans sequences. Three isolates were used to test pathogenicity on detached cataphylls and onion plants tests in the laboratory and greenhouse, respectively. Cataphylls (n=10) were surface disinfected with 2% NaOCl for 2 min, placed in sterile Petri dishes, and injected with 50 µL (106 UFC/mL) inoculum suspension with the aid of a hypodermic syringe. Cataphylls were incubated in humid chamber at 22 + 2ºC for 14 days. Additionally, three-month-old onion plants (n=10), growing in pod, were inoculated by injecting leaves with 1 mL inoculum suspension (106 UFC/mL). Plant were incubated under greenhouse for 30 days to 28ºC. An equal number of cataphylls and onion plants, injected with sterile water, were left as controls. Water soaked lesions on inoculated cataphylls appeared five days after inoculation. While onions plants develop water soaked lesion 1- 4 days after inoculation. Blight and bulb rot were observed only on inoculated plants. Symptoms were identical to those previously observed in the field. Reisolations were accomplished for 100% of the inoculated cataphylls and leaves fulfilling Koch's postulates (Biochemical characterization and PCR amplification of partial 16S rRNA). Previously, Pectobacterium carotovorum was reported causing a similar disease in Chile (Acuña 2008). However, to our knowledge this is the first report of P. agglomerans causing onion leaf blight and bulb rot in O'Higgins Region, Chile. In agreement with other reports (De Armas et al. 2015, Tho et al. 2015), leaf blight and bulb has been a very aggressive disease in Chile. These results do not exclude the possibility that other Pantoea species (Armas et al. 2015) may be involved in the leaf blight and bulb rot of onions.

Culturable Diversity and Biological Properties of Bacterial Endophytes Associated with the Medicinal Plants of Vernonia anthelmintica (L.) Willd

As one of the important traditional medicinal plants listed in the Chinese pharmacopoeia, Vernonia anthelmintica (L.) Willd has been shown to possess various biological activities. In this study, we characterized culturable endophytic bacteria associated with the medicinal plant V. anthelmintica collected from Hotan within the Xinjiang autonomous region of China. Bacterial endophytes were identified via 16S rRNA gene sequence analysis and compared to similar sequences from the GenBank. Isolated strains exhibited 99.08–100% similarity to Bacillus haynesii XJB-5, Bacillus proteolyticus XJB-16, Bacillus halotolerans XJB-35, Bacillus safensis XJB-71, Pseudomonas punonensis XJB-7, Lysinibacillus fusiformis XJB-17, Streptococcus lutetiensis XJB-66, Leclercia adecarboxylata XJB-12, Paenibacillus alvei XJB-14, and Pantoea agglomerans XJB-62. The ethyl acetate extracts of the bacterial endophytes demonstrated various pharmacological properties, such as antimicrobial, cytotoxic, antidiabetic, and antioxidant activity, according to a melanin content assay and have shown tyrosinase activity in murine B16 cells. A crude extract of B. halotolerans XJB-35 displayed more powerful biological activities than other bacterial endophytes; therefore, this strain was studied further in order to select the optimized parameters for enhancing the synthesis of bioactive compounds. The optimal culture medium was found to be nutrient broth (NB) medium, using peptone as its carbon source and yeast extract as its nitrogen source. A 24 h incubation time produced the optimal conditions for the maximum growth of B. halotolerans XJB-35 and the production of bioactive compounds. Moreover, we investigated the volatile chemical component of the dichloromethane fraction using GC-MS analysis. Our findings provide valuable information regarding the synthesize of bioactive natural products by B. halotolerans XJB-35 for use by the medicinal and pharmaceutical industries.

Rhizobacteria Increases Growth and Development of Blackberry Saplings

In this study, the effects of rhizobacteria on vegetative growth of Chester Thornless blackberry cultivars saplings were investigated. In this context, plant height, shoot number, stem diameter, average shoot length, root length, plant fresh and dry weight, root fresh and dry weight, IAA, ABA, GA, cytokinin, zeatin hormones and N, P, K, Ca, Mg, S, Mn, Fe, Zn, Cu, Na nutrients were investigated. According to the evaluations, the highest plant fresh and dry weights and root fresh and dry weights were obtained from the SK50 bacteria strain. It was determined that plant height, stem diameter, average shoot length and root length maximum increased with SK-39 strain. Bacteria applications increased the IAA, GA, cytokinin and zeatin contents and decreased the ABA content in the leaves. With bacteria applications, leaf N, P, K, Ca, S, Zn, Cu and Na contents increased compared to control. According to the results of the research, it can be recommended to use Herbaspirillum huttiense SK-39, Achromobacter xylosoxidans denitrificans SK-50, Pantoea agglomerans GC subgroup SY-43 and Microbacterium ester aromaticum SY-48 bacteria strains in order to promote growth and development in the cultivation of blackberry cultivars.

Large effect of phosphate-solubilizing bacteria on the growth and gene expression of Salix spp. at low phosphorus levels.

Phosphorus is one of the most important nutrients required for plant growth and development. However, owing to its low availability in the soil, phosphorus is also one of the most difficult elements for plants to acquire. Phosphorus released into the soil from bedrock quickly becomes unavailable to plants, forming poorly soluble complexes. Phosphate-solubilizing bacteria (PSB) can solubilize unavailable phosphorus-containing compounds into forms in which phosphorus is readily available, thus promoting plant growth. In this study, two willow species, Salix dasyclados cv. Loden and Salix schwerinii × Salix viminalis cv. Tora, were inoculated with two selected bacterial strains, Pantoea agglomerans and Paenibacillus spp., to evaluate the plant growth parameters and changes in gene expression in the presence of different concentrations of tricalcium phosphate: 0 mM (NP), 1 mM (LP), and 2 mM (HP). Inoculation with PSB increased root, shoot and leaf biomass, and for the HP treatment, significant changes in growth patterns were observed. However, the growth responses to plant treatments tested depended on the willow species. Analysis of the leaf transcriptomes of the phosphate-solubilizing bacterium-inoculated plants showed a large variation in gene expression between the two willow species. For the Tora willow species, upregulation of genes was observed, particularly for those involved in pathways related to photosynthesis, and this effect was strongly influenced by bacterial phosphate solubilization. The Loden willow species was characterized by a general downregulation of genes involved in pathway activity that included ion transport, transcription regulation and chromosomes. The results obtained in this study provide an improved understanding of the dynamics of Salix growth and gene expression under the influence of PSB, contributing to an increase in yield and phosphorus-use efficiency.

Contribution of potassium solubilizing bacteria in improved potassium assimilation and cytosolic K+/Na+ ratio in rice (Oryza sativa L.) under saline-sodic conditions.

Sodium-induced potassium (K+) deficiency is more prevalent in salt-affected soils. Plants experience K+ starvation thus cytosolic K+/Na+ ratio is lowered, which is a prerequisite for their survival. K+ enrichment in crops can be acquired via K-solubilizing bacteria as a sustainable green agriculture approach. This study was conducted to explore potent K-solubilizing bacteria from the rhizosphere of wheat, rice, and native flora grown in salt-affected soils in two distinct regions of Pakistan. The aim of this work was to evaluate the contribution of microbial consortiums to the improvement of K+ assimilation and cytosolic K+/Na+ ratios in rice crops under saline-sodic conditions. Among 250 bacterial isolates, 9 were selected based on their salt (11% NaCl) and alkali (9) tolerance and K-solubilization indices (1.57-5.67). These bacterial strains were characterized for their plant growth-promoting traits and identified based on 16S rRNA gene sequencing. A consortium of five strains, namely, Enterobacter hormaechei, Citrobacter braakii, Pseudomonas putida, Erwinia iniecta, and Pantoea agglomerans, was used as a bio-inoculant to evaluate its role in K+ assimilation, cytosolic K+/Na+ ratio, and subsequent yield enhancement in rice grown under saline-sodic conditions. The impact of applied consortium on rice was assessed under variable salt levels (Control, 40, 80, and 120 mM) in a pot experiment and under natural saline-sodic conditions in the field. Plant agronomical parameters were significantly higher in the bacterial consortium-treated plants, with a concomitant increase in K+-uptake in root and shoot (0.56 and 0.35 mg g-1 dry wt.) of the salt-tolerant rice variety Shaheen. The root K+/Na+ ratio was significantly improved (200% in 40 mM and 126% in 80 mM NaCl) and in the shoot (99% in 40 mM and 131% in 80 mM) too. A similar significant increase was also observed in the salt-susceptible variety Kainat. Moreover, grain yield (30.39 g/1,000 grains wt.) and biomass (8.75 g) of the rice variety Shaheen, grown in field conditions, were also improved. It can be concluded that K-solubilizing bacteria can be used as bio-inoculants, contributing to growth and yield increment via enhanced K-assimilation and cytosolic K+/Na+ ratio in rice crops under salt stress.

Assessment of Antibiotic Resistance Patterns of Bacterial Pathogens Isolated from Blood Culture Specimens at Livingstone University Teaching Hospital in Zambia

Background. Bloodstream infections (BSI) are of public health concern because they are usually associated with high fatality rate if therapy is delayed. A combination of these infections with antibiotic resistance increases healthcare costs. In this study, microorganisms identified from blood cultures at Livingstone University Teaching Hospital (LUTH) between 2019 and 2021 were evaluated for their antibiotic resistance patterns. Methods: This was a single-centre laboratory based retrospective study. Data on isolated organisms from electronic laboratory system generated reports at LUTH microbiology laboratory for a period of 3 years, was analysed with SPSS version 20. Results: A total of 765 specimens were processed and only 331 (43.3%) met the inclusion criteria. Of the 331 specimens, 61.3% and 38.7% were collected from female and male patients, respectively whereas 65.9% came from out-patient departments and 34.1% from in-patient departments. The commonest bacteria isolate was Escherichia coli (27.2%) followed by Enterobacter agglomerans (22.7%), Klebsiella pneumoniae (13%), Klebsiella oxytoca (6.3%), Enterobacter aerogenes (5.4%), Enterobacter cloacae (5.4%), Citrobacter freundii (4.8%), Serratia marcescens (3.6%), Proteus mirabilis (3.3%), and Staphylococcus aureus (2.7%). Of the common utilized antibiotics, ampicillin (92.9%) was the least effective drug followed by co-trimoxazole (82.7%), nalidixic acid (68.3%), penicillin (66.7%), tetracycline (63.5%), and chloramphenicol (50.3%), while imipenem (15.4%), norfloxacin (35.3%), and nitrofurantoin (38.8%) were the most effective. The patient's gender and hospital location may have an impact on antibiotic resistance. Conclusion: The most common bacterial pathogens were Gram-negative Enterobacteriaceae that showed increased resistance to various classes of commonly used antibiotics at LUTH but with low resistance to imipenem. Due to the observed multidrug resistant pathogens for BSI, it is cardinal for healthcare facilities to monitor bacteria resistance patterns regularly and encourage the prudent use of antibiotics. However, antibiotic selection for susceptibility testing should be based on the Clinical and Laboratory Standards Institute (CLSI) and Zambia National Formulary (ZNF) recommendations to only test antibiotics1r for BSI instead of those recommended for other infections like urinary tract infections (e.g., tetracyclines).

Enhancement of β-carotene content in Chlamydomonas reinhardtii by expressing bacterium-driven lycopene β-cyclase

β-Carotene is one of the economically important carotenoids, having functions as the antioxidant to remove harmful free radicals and as the precursor for vitamin A and other high-valued xanthophyll such as zeaxanthin and astaxanthin. Lycopene cyclase plays an important role in the branching of β-carotene and α-carotene. Aiming to develop the microalgae with enhanced β-carotene productivity, the CrtY gene from bacterium Pantoea agglomerans was integrated into Chlamydomonas reinhardtii. The lycopene-producing E. coli harboring CrtY gene produced 1.59 times of β-carotene than that harboring DsLcyb1 from Dunaliella salina (a microalga with abundant β-carotene), confirming the superior activity of CrtY on β-carotene biosynthesis. According to the pigment analysis by HPLC, in microalgal transformants that were confirmed by molecular analysis, the expression of CrtY significantly increased β-carotene content from 12.48 mg/g to 30.65 mg/g (dry weight), which is about 2.45-fold changes. It is noted that three out of five transformants have statistically significant higher amount of lutein, even though the increment was 20% in maximum. Besides, no growth defect was observed in the transformants. This is the first report of functional expression of prokaryotic gene in eukaryotic microalgae, which will widen the gene pool targeting carotenoids biosynthesis using microalgae as the factory and thereby provide more opportunity for high-valued products engineering in microalgae.