Isolation of actinomycetes from Sabah and the screening for inhibitor against Eukaryotic signal transdustion

Actinomycetes strains isolated from 504 soil samples collected from Sabah terrestrial ecosystem were studied and screened for novel bioactive compounds inhibitory against eukaryotic signal transduction. All the soil samples were collected under trees identified to species or genus level. Isolation of Streptomyces and non-Streptomyces actinomycetes on HV (humic acid + B-vitamins) medium yielded 569 strains. Morphology characterisation of the isolated actinomycetes was carried out including aerial mycelium, substrate colour, diffusible pigment and spore morphology- on oatmeal medium while chemotaxonomic identification based on Diaminopimelic Acid. All actinomycetes strains were grown under aerobic condition in liquid culture and extracted with acetone. In this research, yeast MAPK kinase and MAP kinase phosphatase are the molecular level targeted proteins. The screening system was developed for searching MAPK kinase and MAP kinase phosphatase inhibitors. MKKIP386 and MKKI P386-MSG5 mutant yeast were used to screen for inhibitors, as these yeast kinase and phosphatase have homologous proteins in the MAP kinase signal transduction pathway in human. Strain H7553 and H7597 showed potential MAPK kinase inhibitors. The in vivo RaslRaf interaction with the yeast two hybrid screening system was used to screen against RaslRaf protein interaction inhibitor. Strain H7520 showed potential inhibitor for yeast Type 1 protein serine/threonine phosphatase (GLC7) screening system. Extract H7944 showed inhibition effect in the ERK signal transduction (the chain-reaction of phosphorylation from MEK 112 to ERK 112) when inhibited phosphorylation of MEK to ERK. Thus, strain H7944 (MBA94-2) was able to prevent activation of MEK. Strain H7944 was a potential MEK 112 inhibitor since p-galactosidase assay confirmed that H7944 do not inhibited the Ras/Raf pathway. Aktinomiset dipencilkan daripada 504 sampel tanah dikutip dari ekosistem Sabah dikaji dan penyaringan compaun bioaktif terhadap perencatan transduksi isyarat eukariot. Semua sampel tanah dikutip di bawah pokok yang dikenalpasti sehingga peringkat spesies atau genus. Pemencilan aktimomiset Streptomyces dan bukan Streptomyces menggunakan media asid humik-vitamin (HV) agar be~aya memencilkan sebanyak 569 strain aknomiset. Pencirian morfologi strain aktinomiset yang dipencilkan dilakukan melalui pencirian warna aerial miselium, warna substrak dan penyebaran warna pigment ke atas media agar oatmeal manakala pencirian kimiataksonomi dilakukan melalui teknik isomer asid diaminopimelik. Semua strain aktinomiset dikulturkan secara aerobik dalam media cecair dan diekstrak dengan menggunakan aseton. Dalam kajian ini, MAPK kinase dan MAP kinase fosfotase adalah sasaran protein molekular dalam yis. Sistem penyaringan dibangunkan untuk mencari perencat untuk MAPK kinase dan MAP kinase fosfotase. Vis mutant, MKK 1 P386 dan MKK 1 P386 -MSG5 digunakan untuk tujuan penyaringan disebabkan kinase dan fosfotase yis mempunyai persamaan dengan protein dalam transduksi isyarat MAP kinase dalam manusia. Strain H7553 dan H7597 menunjukkan potensi perencat untuk MAPK kinase. Sistem penyaringan in vivo interakasi RasIRaf dalam yis dual-hybrid digunakan untuk menyaring perencat protein interakasi RaslRaf. Ekstrak daripada aktinomiset H7520 menunjukkan potensi perencat untuk protein serine/threonine fosfotase (GLC7) dalam yis dalam penyaringan yang dijalankan. Ekstrak H7944 menunjukkan kesan perencatan dalam isyarat transduksi apabila ia merencat fosforilasi terhadap MEK daripada ERK. Ini bermakna H7944 berupaya mencegah pengaktifan MEK. Strain H7944 mempunyai potensi menjadi perencat MEK 1/2 kerana kajian p-galaktosidase yang dijalankan menunjukkan ia tidak merencat kitaran Ras/Ra

Bioactivities and mode of actions of dibutyl phthalates and nocardamine from Streptomyces sp. H11809

Dibutyl phthalate (DBP) produced by Streptomyces sp. H11809 exerted inhibitory activity against human GSK-3β (Hs GSK-3β) and Plasmodium falciparum 3D7 (Pf 3D7) malaria parasites. The current study aimed to determine DBP’s plausible mode of action against Hs GSK-3β and Pf 3D7. Molecular docking analysis indicated that DBP has a higher binding affinity to the substrate-binding site (pocket 2; −6.9 kcal/mol) than the ATP-binding site (pocket 1; −6.1 kcal/mol) of Hs GSK-3β. It was suggested that the esters of DBP play a pivotal role in the inhibition of Hs GSK-3β through the formation of hydrogen bonds with Arg96/Glu97 amino acid residues in pocket 2. Subsequently, an in vitro Hs GSK-3β enzymatic assay revealed that DBP inhibits the activity of Hs GSK-3β via mixed inhibition inhibitory mechanisms, with a moderate IC50 of 2.0 µM. Furthermore, the decrease in Km value with an increasing DBP concentration suggested that DBP favors binding on free Hs GSK-3β over its substrate-bound state. However, the antimalarial mode of action of DBP remains unknown since the generation of a Pf 3D7 DBP-resistant clone was not successful. Thus, the molecular target of DBP might be indispensable for Pf survival. We also identified nocardamine as another active compound from Streptomyces sp. H11809 chloroform extract. It showed potent antimalarial activity with an IC50 of 1.5 µM, which is ~10-fold more potent than DBP, but with no effect on Hs GSK-3β. The addition of ≥12.5 µM ferric ions into the Pf culture reduced nocardamine antimalarial activity by 90% under in vitro settings. Hence, the iron-chelating ability of nocardamine was shown to starve the parasites from their iron source, eventually inhibiting their growth

Screening for eukaryotic signal transduction and Mycobacterium isocitrate lyase inhibitor from actinomycetes and fungi of dipterocarp rain forests at Imabak Valey, Sabah, Malaysia

A diversity of actinomycetes and fungi was isolated from various sites during the Imbak Valley Scientific Expedition 2000. A total of 144 soil samples were collected under trees that have been identified to species or genus level. Imbak Valley is a lowland dipterocarp forest, which is interestingly dominated by Dryobalanops beccarii. Isolation of Streptomyces and non-Streptomyces actinomycetes on HV medium and other specific isolation media for non-Streptomyces yielded 203 isolates from 89 soil samples. Morphological characterisation of the isolated actinomycetes was carried out based on aerial mycelium colour, substrate mycelium colour and diffusible pigment production on oatmeal medium. Nine strains of fungi were isolated from the six soil samples plated on PDA medium. All actinomycetes isolates were grown under aerobic condition in liquid culture and extracted with acetone, and used for screening against proteins involved eukaryotic signal transduction. Yeast MAPK kinase and MAP kinase phosphatase were some of the targeted proteins used in this research. MKK1P386 and MKK1P386-MSG5 mutant yeasts were used to screen for these inhibitors, as these yeast kinase and phosphatase have homologous proteins in the MAP kinase signal transduction pathway in human. No inhibitors in the extracts were found in these screenings. Type 1 protein serine/ threonine phosphatase (GLC7) in yeast was used to screen inhibitors against PP1 inhibitors and no inhibitor was found. None of the fungal extracts showed any inhibitory activities in all the screening systems. No Ras/Raf inhibitor was found in the in vivo Ras/Raf interaction with the yeast two-hybrid screening system, which used to screen for inhibitor against Ras/ Raf protein interaction inhibitor. There were 11 actinomycetes extracts that showed toxicity against yeast strain LZ (transformant of Ras/ Raf). H7667, a Streptomycete toxic to yeast is further screened for inhibitors of the GSK3-beta pathway. H7763, a Streptomyces species that showed positive in the primary screen for inhibitor of isocitrate lyase (ICL) which is not itaconic acid (known ICL inhibitor). H7240 showed the strongest susceptibility towards the resin in which the concentration of 5g/l of resin is sufficient to produce growth inhibition of the bacteria

Updates on Dengue Vaccine and Antiviral: Where Are We Heading?

Approximately 100–400 million people from more than 100 countries in the tropical and subtropical world are affected by dengue infections. Recent scientific breakthroughs have brought new insights into novel strategies for the production of dengue antivirals and vaccines. The search for specific dengue inhibitors is expanding, and the mechanisms for evaluating the efficacy of novel drugs are currently established, allowing for expedited translation into human trials. Furthermore, in the aftermath of the only FDA-approved vaccine, Dengvaxia, a safer and more effective dengue vaccine candidate is making its way through the clinical trials. Until an effective antiviral therapy and licensed vaccine are available, disease monitoring and vector population control will be the mainstays of dengue prevention. In this article, we highlighted recent advances made in the perspectives of efforts made recently, in dengue vaccine development and dengue antiviral drug

Updates on Dengue Vaccine and Antiviral: Where Are We Heading?

Approximately 100–400 million people from more than 100 countries in the tropical and subtropical world are affected by dengue infections. Recent scientific breakthroughs have brought new insights into novel strategies for the production of dengue antivirals and vaccines. The search for specific dengue inhibitors is expanding, and the mechanisms for evaluating the efficacy of novel drugs are currently established, allowing for expedited translation into human trials. Furthermore, in the aftermath of the only FDA-approved vaccine, Dengvaxia, a safer and more effective dengue vaccine candidate is making its way through the clinical trials. Until an effective antiviral therapy and licensed vaccine are available, disease monitoring and vector population control will be the mainstays of dengue prevention. In this article, we highlighted recent advances made in the perspectives of efforts made recently, in dengue vaccine development and dengue antiviral drug

A Review: Natural and Synthetic Compounds Targeting Entamoeba histolytica and Its Biological Membrane

Amoebiasis is the third most common parasitic cause of morbidity and mortality, particularly in countries with poor hygienic settings in central and south America, Africa, and India. This disease is caused by a protozoan parasite, namely Entamoeba histolytica, which infects approximately 50 million people worldwide, resulting in 70,000 deaths every year. Since the 1960s, E. histolytica infection has been successfully treated with metronidazole. However, there are drawbacks to metronidazole therapy: the side effects, duration of treatment, and need for additional drugs to prevent transmission. Previous interdisciplinary studies, including biophysics, bioinformatics, chemistry, and, more recently, lipidomics studies, have increased biomembranes’ publicity. The biological membranes are comprised of a mixture of membrane and cytosolic proteins. They work hand in hand mainly at the membrane part. They act as dedicated platforms for a whole range of cellular processes, such as cell proliferation, adhesion, migration, and intracellular trafficking, thus are appealing targets for drug treatment. Therefore, this review aims to observe the updated trend of the research regarding the biological membranes of E. histolytica from 2015 to 2021, which may help further research regarding the drug targeting the biological membrane

Yeast Glycogen Synthase Kinase-3β Pathway Inhibitors from an Organic Extract of Streptomyces sp.

Investigation of a microbial fermentation organic extract of Streptomyces sp. H7667 led to the isolation of three new imides, 3-[(5E)-5-methyl-4-oxo-2-hydroxy-5-octenyl]glutarimide (1), 2-amino-N-2′-(phenylacetyl)propanimide (5), and 2-amino-N-(2′-(cyclohex-2′′-enyl)acetyl)acetimide (6), and one new isoflavonoid glycoside, 6-O-methyl-7-O-Rrhamnopyranosyldaidzein (7), along with four known compounds. Their structures were elucidated by HRESIMS, 1H and 13C NMR, COSY, HMQC, HMBC, and NOESY spectra. Compounds 1-8 were evaluated for their inhibitory activities in the yeast glycogen synthase kinase-3� assay

Acute Oral Toxicity and Brine Shrimp Lethality of Elaeis guineensis Jacq., (Oil Palm Leaf) Methanol Extract

Elaeis guineensis (Arecaceae) is widely used in West African traditional medicine for treating various ailments. An evaluation on the toxicity of extracts of this plant is crucial to support the therapeutic claims. The acute oral toxicity and brine shrimp lethality of a methanolic extract of this plant was tested. Oral administration of crude extract at the highest dose of 5,000 mg/kg resulted in no mortalities or evidence of adverse effects, implying that E. guineensis is nontoxic. Normal behavioral pattern, clinical signs and histology of vital organs confirm this evidence. The E. guineensis extracts screened for toxicity against brine shrimp had 50% lethal concentration (LC50) values of more than 1.0 mg/mL (9.00 and 3.87 mg/mL, at 6 and 24 h, respectively), confirming that the extract was not toxic. Maximum mortalities occurred at 100 mg/mL concentration while the least mortalities happened to be at 0.195 mg/mL concentration. The results of both tests confirm that E. guineensis is nontoxic and hence safe for commercial utilization