Screening of Locally Isolated Actinomycetes and Endophytic Fungi for Production of Bioactive Compounds

Isolation of actinomycetes were done using Humic acid B-vitamins Agar (HVA) while endophytic fungi were from Potato Dextrose Agar (PDA). Isolated strains were then subjected to enzymatic and also antimicrobial testing. Positive strains for antimicrobial testing were then subjected to carbon source utilization testing and viewed under microscope to determine their spores morphology. From the enzymatic test conducted for actinomycetes, 110 isolates showed positive result for cellulase activity, 107 for xylanase activity and 22 for mannanase activity. Fifteen isolates of endophytic fungi have the ability to degrade cellulose, 28 of the isolates were able to degrade xylan and 12 isolates have the potential to degrade mannan. Thirteen isolates of actinomycetes showed positive result towards the 5 strains of pathogenic microorganisms with the highest on Yersinia enterocolitica. While test done using endophytic fungi showed only 1 isolate with antimicrobial property toward Xanthomonas campestris. Biolog test was done to determine the metabolite diversity of each actinomycetes. Twelve of the 13 isolates of actinomycetes were identified to be from the genus of Streptomyces by observing their spore arrangement and 1 of the isolate could not be identified. Biolog test could not be done on the endophytes fungi strain 13 because this strain does not produce spores.Through microscopic imaging the identity of the endophytes fungi isolate also could not be determined. Actinomycetes isolate number 200 was further identified by targeting its 16S rRNA gene. By using this technique Actinomycetes isolate number 200 was confirmed to be from the genus Streptomyces

Effects of different parameters on cellulase production by Trichoderma harzianum TF2 using solid‐state fermentation (SSF)

Solid‐state fermentation is one of the easiest and cheapest methods for producing microbial bioactive com‐ pounds. Trichoderma harzianum has long been recognised as one of the potential fungi for this purpose. Trichoderma sp. were isolated from banana rhizosphere using the soil dilution method and later screened for their ability to produce cellulases using filter paper activity (FPase) and the carboxylmethyl cellulase (CMCase) test. Trichoderma sp. were also subjected to one factor change at a time to determine the effects of different parameters on cellulase production. It was observed that T. harzianum TF2 showed the ability to produce higher cellulase activity when wheat bran was used as the substrate. The results showed that 38.5 U/g of cellulase was produced with the use of wheat bran coupled with an incubation temperature of 28 °C and moisture content of 60%. T. harzianum TF2 showed good potential for use as a culture for cellulase production in this study due to its higher cellulase production under solid‐state fermentation, with the possibility of its application to industry

Preliminary screening of endophytic fungi isolated from medicinal plants in MARDI Sessang, Sarawak for their bioactivity

A total of 100 isolates of endophytic fungi were isolated from 19 species of medicinal plants collected at MARDI Station Sessang, Sarawak. A total of 55% of the endophytic fungi were isolated from the leaves while 45% from the branches. Screening of isolates for enzymatic secretion found that 15, 28 and 12 isolates were able to hydrolyze cellulose, xylan and mannan respectively. All 100 isolates were also tested for their antimicrobial activity towards selected phytopathogenic and human pathogenic microbes. The test indicated that only one isolate showed positive result when tested against Xanthomonas campestris. The results indicate that the endophytic fungi isolated from medicinal plant at MARDI Research Station Sessang, Sarawak may have the potential to be further exploited for its bioactivity

Diversity of Actinomycetes Isolated from Peat Soil of Undistrubed Forest and Pineapple Plantation in Sessang, Sarawak

Peatland plays an important role not just as a carbon store but also in facilitating the flux of greenhouse gasses into the atmosphere. Apart from that, peatland is also home to a diverse population of microorganisms such as bacteria, fungi, and actinomycetes. Actinomycetes were known to be one of the most ubiquitous microbes that can be found in most of the soil types including peat soil. In this study, seventy isolates of actinomycetes were isolated from the peat soil using the soil dilution method. The 70 isolates of actinomycetes were later screened for their ability to produce secondary metabolites and antimicrobial activities using the agar diffusion method before the selected potential isolates were identified by targeting their 16S rRNA region. The results obtained showed 34.3% produce cellulase followed by, 12.8, 31.7, 80.0, and 51.4% for mannanase, xylanase, lipase, and protease respectively. The percentage of actinomycetes producing antimicrobial activity was 27.1 and 21.4% for Ralstonia solanacearum and Colletotrichum gleosporioides respectively. All the selected isolates of actinomycetes were identified as belonging to the genus of Streptomycetes spp. The potential actinomycetes were stored in freeze-dried form for future usage. This study showed that  more diverse population of actinomycetes was obtained from the undisturbed forested peat soil area ecosystem compared to the agricultural peat soil area.

Isolation and screening of actinomycetes from Malaysian soil for their enzymatic and antimicrobial activities

Actinomycetes, a slow growing gram positive bacteria, are known as an organism that is useful in the search for bioactive compounds. In this study, 212 isolates of actinomycetes were isolated from soil samples collected in the area of Serdang, Bangi, Petaling Jaya and Putrajaya. From the total of 212 isolates, 91 showed the ability to degrade cellulose; 16 for mannan and 90 for xylan. The 212 isolates were then subjected to anti-microbial testing, where they were tested for their ability to produce anti-microbial activity against selected phytopathogens. From the test, only two strains of isolates (strain 161 and 176) showed positive result towards Xanthomonas campestris. These two isolates were then identified using research microscope

Purification and properties of polygalacturonase associated with the infection process of Colletotrichum truncatum CP2 in chilli

In this study, polygalacturonase enzyme produced by Colletotrichum truncatum CP2 was partially purified by aqueous two-phase system and the properties of this enzyme was characterized. The highest yield (57.4%) and purification fold (5.1) was obtained using 22% PEG 6,000/15% sodium citrate comprising crude load of 16% (w/w) at pH 7.0 with addition of 1.0% (w/w) sodium chloride. The partially purified PG remained active over a wide range of pH (2.5-6.0) and the optimum activity was obtained at pH 5.0. Incubation of the partially purified PG at 40 and 50 °C for 30 min caused the activity of PG to decrease up to 20% and 40%, respectively. However, no significant changes in the activity when the enzymes were incubated up to 4 h at 40 and 50 °C. The results from this study suggested that ATPS comprising of PEG and sodium citrate could be potentially used as an alternative method for purification of PG

Typing of Ralstonia solanacearum isolated from tomato by antibiotic susceptibility, plasmid profiling and PCR-based techniques of RAPD and ERIC

The epidemiological characteristics of Ralstonia solanacearum isolated from tomato plants in Sarawak and Selangor were studied. The epidemiological analysis of the strains was carried out through antibiotic resistant pattern, plasmid profiles, randomly amplified polymorphic DNA (RAPD) and enterobacterial repetitive intergenic consensus (ERIC) methods. Six strains were susceptible to all antibiotics tested, whereas the 10 strains that were resistant to one or more antibiotics were grouped into six antibiotic resistance patterns. Small single plasmid of 7.2 Mda and 9.2 Mda were detected among the nine plasmid containing strains, enabling them to be grouped into only two plasmid patterns. In the polymerase chain reaction, based methods using RAPD and ERIC, two strains were untypable by RAPD, whereas all were typable by ERIC. In this study, a wide diversity of R. solanacearum strains was examined. ERIC analysis demonstrated the clonal relationship between isolates from tomato plants in Sarawak and Selangor. The existence of similar R. solanacearum strains in tomato plants from two very distant locations should be considered if tomato strain fingerprint results were to be used to help trace the vehicles for transmission

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Isolation of Potential Fluorescent Pseudomonads from Kuini (Mangifera odorata) Planted Soil and Their Potential as Biofertilizer

Pseudomonas sp. are known to be good Plant Growth Promoting Rhizobacteria (PGPR). In this study, Pseudomonas sp. were isolated from soil planted with kuini (Mangifera odorata) using soil dilution method and spread onto King’s B media. Five isolates of Pseudomonas sp. were observed to give promising results in the phytohormone and antimicrobial test conducted. These isolates are Pseudomonas sp. isolate K24pf, K29pf, K32pf, K33pf and K37pf. From the 5 potential isolates, Pseudomonas sp. isolate K29pf was chosen because it showed potential activity in producing marked amounts of Indole-3-Acetic Acid and gibberellic acid. Pseudomonas sp. isolate K29pf also produced antimicrobial activities towards Ralstonia solanacearum, Erwinia caratovora, Erwinia mallotivora and Colletotrichum gloeosporioides. Seed germination test showed that Pseudomonas sp. isolate K29pf was able to promote approximately 90% growth of Brassica chinensis seeds. Pot trial conducted showed that Treatment 3 (+OF+PGPR) was able to increase Brassica chinensis root by 36.5% and 28.4% of its biomass compared to treatment using Treatment 1 (+OF)

Isolation, characterization and identification of potential actinobacteria with antifungal activities towards chilli anthracnose

Actinobacteria from the genus of Streptomycetes have been regarded as the most potent producers of bioactive compounds in the world. In this study, a total of 132 isolates of actinobacteria were isolated from rhizospheres of various plant species planted at MARDI Langkawi Agro Technology Park, Malaysia. These isolates were screened for the ability to inhibit the growth of pathogenic fungi, Colletotrichum capsisi and Colletotrichum gloeosporioides isolated from chilli fruit. From these screening it revealed that 45 isolates of actinobacteria were able to produce antifungal activity towards C. capsici, while 67 isolates produced antifungal activity towards C. gloeosporioides. Out of these 132 isolates, 2 of the best antifungal-producer were selected and identified as Streptomyces spp. strain PM2 and PM4. Observation using scanning electron microscope (SEM) showed that the spore surface for both Streptomyces spp. strain PM2 and PM4 were rough and spiky. Physiological characterization of both strains showed their ability to grow in 1 to 4% of NaCl, growth temperature of 17 to 35°C and pH of 5 to 11. The ability of these Streptomyces spp. to secrete antifungal compounds may have been related to the availibility of the carbon sources. These findings suggest that Streptomyces spp. strain PM2 and PM4 are potential candidate for biocontrol against anthracnose disease