The marine actinomycete genus Salinispora: a model organism for secondary metabolite discovery

This review covers the initial discovery of the marine actinomycete genus Salinispora through its development as a model for natural product research. A focus is placed on the novel chemical structures reported with reference to their biological activities and the synthetic and biosynthetic studies they have inspired. The time line of discoveries progresses from more traditional bioassay-guided approaches through the application of genome mining and genetic engineering techniques that target the products of specific biosynthetic gene clusters. This overview exemplifies the extraordinary biosynthetic diversity that can emanate from a narrowly defined genus and supports future efforts to explore marine taxa in the search for novel natural products

Purification and biochemical characterization of taxadiene synthase from bacillus koreensis and stenotrophomonas maltophilia

Taxadiene synthase (TDS) is the rate-limiting enzyme of Taxol biosynthesis that cyclizes the geranylgeranyl pyrophosphate into taxadiene. Attenuating Taxol productivity by fungi is the main challenge impeding its industrial application; it is possible that silencing the expression of TDS is the most noticeable genomic feature associated with Taxol-biosynthetic abolishing in fungi. As such, the characterization of TDS with unique biochemical properties and autonomous expression that is independent of transcriptional factors from the host is the main challenge. Thus, the objective of this study was to kinetically characterize TDS from endophytic bacteria isolated from different plants harboring Taxol-producing endophytic fungi. Among the recovered 23 isolates, Bacillus koreensis and Stenotrophomonas maltophilia achieved the highest TDS activity. Upon using the Plackett–Burman design, the TDS productivity achieved by B. koreensis (18.1 µmol/mg/min) and S. maltophilia (14.6 µmol/mg/min) increased by ~2.2-fold over the control. The enzyme was purified by gel-filtration and ion-exchange chromatography with ~15 overall folds and with molecular subunit structure 65 and 80 kDa from B. koreensis and S. maltophilia, respectively. The chemical identity of taxadiene was authenticated from the GC-MS analyses, which provided the same mass fragmentation pattern of authentic taxadiene. The tds gene was screened by PCR with nested primers of the conservative active site domains, and the amplicons were sequenced, displaying a higher similarity with tds from T. baccata and T. brevifolia. The highest TDS activity by both bacterial isolates was recorded at 37–40 °C. The Apo-TDSs retained ~50% of its initial holoenzyme activities, ensuring their metalloproteinic identity. The activity of purified TDS was completely restored upon the addition of Mg2+, confirming the identity of Mg2+ as a cofactor. The TDS activity was dramatically reduced upon the addition of DTNB and MBTH, ensuring the implementation of cysteine-reactive thiols and ammonia groups on their active site domains. This is the first report exploring the autonomous robust expression TDS from B. koreensis and S. maltophilia with a higher affinity to cyclize GGPP into taxadiene, which could be a novel platform for taxadiene production as intermediary metabolites of Taxol biosynthesis

Exploiting the Biosynthetic Potency of Taxol from Fungal Endophytes of Conifers Plants : Genome Mining and Metabolic Manipulation

Endophytic fungi have been considered as a repertoire for bioactive secondary metabolites with potential application in medicine, agriculture and food industry. The biosynthetic pathways by fungal endophytes raise the argument of acquisition of these machineries of such complex metabolites from the plant host. Diterpenoids "Taxol" is the most effective anticancer drug with highest annual sale, since its discovery in 1970 from the Pacific yew tree,Taxus brevifolia. However, the lower yield of Taxol from this natural source (bark ofT. brevifolia), availability and vulnerability of this plant to unpredicted fluctuation with the ecological and environmental conditions are the challenges. Endophytic fungi fromTaxusspp. opened a new avenue for industrial Taxol production due to their fast growth, cost effectiveness, independence on climatic changes, feasibility of genetic manipulation. However, the anticipation of endophytic fungi for industrial Taxol production has been challenged by the loss of its productivity, due to the metabolic reprograming of cells, downregulating the expression of its encoding genes with subculturing and storage. Thus, the objectives of this review were to (1) Nominate the endophytic fungal isolates with the Taxol producing potency from Taxaceaeand Podocarpaceae; (2) Emphasize the different approaches such as molecular manipulation, cultural optimization, co-cultivation for enhancing the Taxol productivities; (3) Accentuate the genome mining of the rate-limiting enzymes for rapid screening the Taxol biosynthetic machinery; (4) Triggering the silenced rate-limiting genes and transcriptional factors to activates the biosynthetic gene cluster of Taxol

Image_6_Antibacterial activity of bioactive compounds extracted from red kidney bean (Phaseolus vulgaris L.) seeds against multidrug-resistant Enterobacterales.JPEG

In the present study, biologically active compounds such as phenolic-rich extract (PRE), 7S globulin (vicilin), and 11S globulin (legumin) from red kidney bean (Phaseolus vulgaris L.) seeds were extracted and evaluated as antibacterial agents against multidrug-resistant (MDR) Enterobacterales isolated from both animal and human sources. The overall occurrence rate of Enterobacterales was 43.6%, which significantly differed between animal (38.75%) and human (56.67%) sources. Antimicrobial susceptibility testing revealed that Enterobacterales isolates exhibited full resistance (100%) to amoxicillin-clavulanic acid, followed by ampicillin (75.44%), erythromycin (71.93%), cefoxitin (70.18%), amoxicillin (66.66%), ceftriaxone (64.91%), and trimethoprim/sulfamethoxazole (56.14%). Worthy of note, 97.92% of Enterobacterales isolates were MDR. The total phenolic contents (TPC; 53 ± 2 mg GAE g-1) and total flavonoid contents (TFC; 26 ± 1 mg QE g-1) were recorded. The major phenolic and flavonoid components were catechol (17.63 μg/mL) and hesperidin (11.37 μg/mL), respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to detect the 7S and 11S globulin‘s molecular mass. The data revealed that red kidney bean protein isolate (KPI) includes two major portions: 7S and 11S globulins. The bioactive compounds of Phaseolus vulgaris were investigated for their antibacterial activities against Enterobacterales for the first time. The protein component (MIC = 0.125 – 2 μg/mL; 53.85%) and its 7S and 11S globulin subunits (MIC = 0.5 – 2 μg/mL; 30.77% each) were the most potent extracts, whereas the methanolic extract was the least effective one (MIC = 2 μg/mL; 15.38%). The results displayed the potential of protein bioactive compounds as a hopeful candidate for enhancing future medication plans for the treatment of Enterobacterales originating from animal and human sources.</p

Image_1_Antibacterial activity of bioactive compounds extracted from red kidney bean (Phaseolus vulgaris L.) seeds against multidrug-resistant Enterobacterales.JPEG

In the present study, biologically active compounds such as phenolic-rich extract (PRE), 7S globulin (vicilin), and 11S globulin (legumin) from red kidney bean (Phaseolus vulgaris L.) seeds were extracted and evaluated as antibacterial agents against multidrug-resistant (MDR) Enterobacterales isolated from both animal and human sources. The overall occurrence rate of Enterobacterales was 43.6%, which significantly differed between animal (38.75%) and human (56.67%) sources. Antimicrobial susceptibility testing revealed that Enterobacterales isolates exhibited full resistance (100%) to amoxicillin-clavulanic acid, followed by ampicillin (75.44%), erythromycin (71.93%), cefoxitin (70.18%), amoxicillin (66.66%), ceftriaxone (64.91%), and trimethoprim/sulfamethoxazole (56.14%). Worthy of note, 97.92% of Enterobacterales isolates were MDR. The total phenolic contents (TPC; 53 ± 2 mg GAE g-1) and total flavonoid contents (TFC; 26 ± 1 mg QE g-1) were recorded. The major phenolic and flavonoid components were catechol (17.63 μg/mL) and hesperidin (11.37 μg/mL), respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to detect the 7S and 11S globulin‘s molecular mass. The data revealed that red kidney bean protein isolate (KPI) includes two major portions: 7S and 11S globulins. The bioactive compounds of Phaseolus vulgaris were investigated for their antibacterial activities against Enterobacterales for the first time. The protein component (MIC = 0.125 – 2 μg/mL; 53.85%) and its 7S and 11S globulin subunits (MIC = 0.5 – 2 μg/mL; 30.77% each) were the most potent extracts, whereas the methanolic extract was the least effective one (MIC = 2 μg/mL; 15.38%). The results displayed the potential of protein bioactive compounds as a hopeful candidate for enhancing future medication plans for the treatment of Enterobacterales originating from animal and human sources.</p

Image_5_Antibacterial activity of bioactive compounds extracted from red kidney bean (Phaseolus vulgaris L.) seeds against multidrug-resistant Enterobacterales.JPEG

In the present study, biologically active compounds such as phenolic-rich extract (PRE), 7S globulin (vicilin), and 11S globulin (legumin) from red kidney bean (Phaseolus vulgaris L.) seeds were extracted and evaluated as antibacterial agents against multidrug-resistant (MDR) Enterobacterales isolated from both animal and human sources. The overall occurrence rate of Enterobacterales was 43.6%, which significantly differed between animal (38.75%) and human (56.67%) sources. Antimicrobial susceptibility testing revealed that Enterobacterales isolates exhibited full resistance (100%) to amoxicillin-clavulanic acid, followed by ampicillin (75.44%), erythromycin (71.93%), cefoxitin (70.18%), amoxicillin (66.66%), ceftriaxone (64.91%), and trimethoprim/sulfamethoxazole (56.14%). Worthy of note, 97.92% of Enterobacterales isolates were MDR. The total phenolic contents (TPC; 53 ± 2 mg GAE g-1) and total flavonoid contents (TFC; 26 ± 1 mg QE g-1) were recorded. The major phenolic and flavonoid components were catechol (17.63 μg/mL) and hesperidin (11.37 μg/mL), respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to detect the 7S and 11S globulin‘s molecular mass. The data revealed that red kidney bean protein isolate (KPI) includes two major portions: 7S and 11S globulins. The bioactive compounds of Phaseolus vulgaris were investigated for their antibacterial activities against Enterobacterales for the first time. The protein component (MIC = 0.125 – 2 μg/mL; 53.85%) and its 7S and 11S globulin subunits (MIC = 0.5 – 2 μg/mL; 30.77% each) were the most potent extracts, whereas the methanolic extract was the least effective one (MIC = 2 μg/mL; 15.38%). The results displayed the potential of protein bioactive compounds as a hopeful candidate for enhancing future medication plans for the treatment of Enterobacterales originating from animal and human sources.</p

Image_7_Antibacterial activity of bioactive compounds extracted from red kidney bean (Phaseolus vulgaris L.) seeds against multidrug-resistant Enterobacterales.JPEG

In the present study, biologically active compounds such as phenolic-rich extract (PRE), 7S globulin (vicilin), and 11S globulin (legumin) from red kidney bean (Phaseolus vulgaris L.) seeds were extracted and evaluated as antibacterial agents against multidrug-resistant (MDR) Enterobacterales isolated from both animal and human sources. The overall occurrence rate of Enterobacterales was 43.6%, which significantly differed between animal (38.75%) and human (56.67%) sources. Antimicrobial susceptibility testing revealed that Enterobacterales isolates exhibited full resistance (100%) to amoxicillin-clavulanic acid, followed by ampicillin (75.44%), erythromycin (71.93%), cefoxitin (70.18%), amoxicillin (66.66%), ceftriaxone (64.91%), and trimethoprim/sulfamethoxazole (56.14%). Worthy of note, 97.92% of Enterobacterales isolates were MDR. The total phenolic contents (TPC; 53 ± 2 mg GAE g-1) and total flavonoid contents (TFC; 26 ± 1 mg QE g-1) were recorded. The major phenolic and flavonoid components were catechol (17.63 μg/mL) and hesperidin (11.37 μg/mL), respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to detect the 7S and 11S globulin‘s molecular mass. The data revealed that red kidney bean protein isolate (KPI) includes two major portions: 7S and 11S globulins. The bioactive compounds of Phaseolus vulgaris were investigated for their antibacterial activities against Enterobacterales for the first time. The protein component (MIC = 0.125 – 2 μg/mL; 53.85%) and its 7S and 11S globulin subunits (MIC = 0.5 – 2 μg/mL; 30.77% each) were the most potent extracts, whereas the methanolic extract was the least effective one (MIC = 2 μg/mL; 15.38%). The results displayed the potential of protein bioactive compounds as a hopeful candidate for enhancing future medication plans for the treatment of Enterobacterales originating from animal and human sources.</p

Image_4_Antibacterial activity of bioactive compounds extracted from red kidney bean (Phaseolus vulgaris L.) seeds against multidrug-resistant Enterobacterales.JPEG

In the present study, biologically active compounds such as phenolic-rich extract (PRE), 7S globulin (vicilin), and 11S globulin (legumin) from red kidney bean (Phaseolus vulgaris L.) seeds were extracted and evaluated as antibacterial agents against multidrug-resistant (MDR) Enterobacterales isolated from both animal and human sources. The overall occurrence rate of Enterobacterales was 43.6%, which significantly differed between animal (38.75%) and human (56.67%) sources. Antimicrobial susceptibility testing revealed that Enterobacterales isolates exhibited full resistance (100%) to amoxicillin-clavulanic acid, followed by ampicillin (75.44%), erythromycin (71.93%), cefoxitin (70.18%), amoxicillin (66.66%), ceftriaxone (64.91%), and trimethoprim/sulfamethoxazole (56.14%). Worthy of note, 97.92% of Enterobacterales isolates were MDR. The total phenolic contents (TPC; 53 ± 2 mg GAE g-1) and total flavonoid contents (TFC; 26 ± 1 mg QE g-1) were recorded. The major phenolic and flavonoid components were catechol (17.63 μg/mL) and hesperidin (11.37 μg/mL), respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to detect the 7S and 11S globulin‘s molecular mass. The data revealed that red kidney bean protein isolate (KPI) includes two major portions: 7S and 11S globulins. The bioactive compounds of Phaseolus vulgaris were investigated for their antibacterial activities against Enterobacterales for the first time. The protein component (MIC = 0.125 – 2 μg/mL; 53.85%) and its 7S and 11S globulin subunits (MIC = 0.5 – 2 μg/mL; 30.77% each) were the most potent extracts, whereas the methanolic extract was the least effective one (MIC = 2 μg/mL; 15.38%). The results displayed the potential of protein bioactive compounds as a hopeful candidate for enhancing future medication plans for the treatment of Enterobacterales originating from animal and human sources.</p

Image_8_Antibacterial activity of bioactive compounds extracted from red kidney bean (Phaseolus vulgaris L.) seeds against multidrug-resistant Enterobacterales.JPEG

In the present study, biologically active compounds such as phenolic-rich extract (PRE), 7S globulin (vicilin), and 11S globulin (legumin) from red kidney bean (Phaseolus vulgaris L.) seeds were extracted and evaluated as antibacterial agents against multidrug-resistant (MDR) Enterobacterales isolated from both animal and human sources. The overall occurrence rate of Enterobacterales was 43.6%, which significantly differed between animal (38.75%) and human (56.67%) sources. Antimicrobial susceptibility testing revealed that Enterobacterales isolates exhibited full resistance (100%) to amoxicillin-clavulanic acid, followed by ampicillin (75.44%), erythromycin (71.93%), cefoxitin (70.18%), amoxicillin (66.66%), ceftriaxone (64.91%), and trimethoprim/sulfamethoxazole (56.14%). Worthy of note, 97.92% of Enterobacterales isolates were MDR. The total phenolic contents (TPC; 53 ± 2 mg GAE g-1) and total flavonoid contents (TFC; 26 ± 1 mg QE g-1) were recorded. The major phenolic and flavonoid components were catechol (17.63 μg/mL) and hesperidin (11.37 μg/mL), respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to detect the 7S and 11S globulin‘s molecular mass. The data revealed that red kidney bean protein isolate (KPI) includes two major portions: 7S and 11S globulins. The bioactive compounds of Phaseolus vulgaris were investigated for their antibacterial activities against Enterobacterales for the first time. The protein component (MIC = 0.125 – 2 μg/mL; 53.85%) and its 7S and 11S globulin subunits (MIC = 0.5 – 2 μg/mL; 30.77% each) were the most potent extracts, whereas the methanolic extract was the least effective one (MIC = 2 μg/mL; 15.38%). The results displayed the potential of protein bioactive compounds as a hopeful candidate for enhancing future medication plans for the treatment of Enterobacterales originating from animal and human sources.</p