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Fulltext Comparative Efficacy of Selected Phytobiotics with Halquinol and Tetracycline on Gut Morphology, Ileal Digestibility, Cecal Microbiota Composition and Growth Performance in Broiler Chickens

Basit MA, Kadir AA, Loh TC, Abdul Aziz S, Salleh A, Zakaria ZA, et al.

Animals (Basel), 2020 Nov 19;10(11).
PMID: 33227911 DOI: 10.3390/ani10112150

The current experiment was designed to estimate the comparative efficacy of selected phytobiotics Persicaria odorata leaf meal (POLM) and Piper betle leaf meal (PBLM) with halquinol, and tetracycline in broiler chickens. The 150-day-old broiler chickens were randomly assigned to five dietary groups. The dietary supplementation groups were the basal diet (BD), which served as the negative control (NC), and BD + 0.2 g/kg tetracycline, which served as the positive control (PC); BD + 0.03 g/kg halquinol (HAL), BD + 8 g/kg POLM (Po8), and BD + 4 g/kg PBLM (Pb4) were the treatment groups. Growth performance, gut morphology, ileal digestibility, and cecal microbiota composition were measured. On day 21, the body weight gain (BWG) was enhanced (p < 0.05) in the broiler chickens fed on phytobiotics (Po8 and Pb4) relative to the NC group, however, on day 42 and in terms of overall growth performance, BWG was enhanced (p < 0.05 in diets (Po8, Pb4, HAL and PC) in comparison with the NC group. Conversely, feed conversion ratio (FCR) was recorded reduced (p < 0.05) in Pb4, Po8, HAL, and PC group in comparison with the NC group. Supplementation of phytobiotics (Po8 and Pb4), HAL and PC, positively improved the gut morphology compared to the NC group. Furthermore, the maximum (p < 0.05) villus height (VH) in duodenum and jejunum was observed in broilers fed on diet Pb4. Supplementation of phytobiotics, HAL and PC, improved (p < 0.05) the digestibility of dry matter (DM) (except for HAL), organic matter (OM), crude protein (CP), ether extract (EE), and ash compared to the NC group. Dietary supplementation of phytobiotics (Po8 and Pb4), HAL and PC, significantly reduced the E. coli, Salmonella, and Staphylococcus aureus (except for HAL) counts compared to the NC group. However, supplementation of Pb4 resulted in significantly decreased total anaerobic bacteria and Clostridium spp. counts compared to the NC group. In addition, supplementation of phytobiotics significantly increased the Lactobacillus count compared to HAL, PC, and NC groups. In conclusion, dietary supplementation of phytobiotics improved the gut morphology, positively modulated and maintained the dynamics of cecal microbiota with enhanced nutrient digestibility, thus, increased the growth performance. Based on current results, phytobiotics could be used as an alternative to AGPs for sustainable broiler chicken production.

Matched MeSH terms: Bacteria, Anaerobic
Heavy metals and adsorbents effects on activated sludge microorganisms

Ong SA, Lim PE, Seng CE

Ann Chim, 2004 Jan-Feb;94(1-2):85-92.
PMID: 15141467

The sorption of Cu(II) and Cd(II) from synthetic solution by powdered activated carbon (PAC), biomass, rice husk (RH) and activated rice husk (ARH) were investigate under batch conditions. After activated by concentrated nitric acid for 15 hours at 60-65 degrees C, the adsorption capacity for RH was increased. The adsorbents arranged in the increasing order of adsorption capacities to the Langmuir Q degree parameter were biomass > PAC > ARH > RH. The addition of adsorbents in base mix solution had increased the specific oxygen uptake rate (SOUR) activated sludge microorganisms with and without the presence of metals. The increased of SOUR were due to the ability of PAC and RH in reducing the inhibitory effect of metals on microorganisms and provide a reaction site between activated sludge microorganisms and substrates.

Matched MeSH terms: Bacteria
Fulltext The Safety Of Capsules Containing Lactic Acid Bacilli

Paraidathathu, Thomas, Lee, S.H.

Ann Dent, 1999;6(1):-.
MyJurnal

The population in Malaysia use various types of health and food supplements. These products are considered safe and are used without any concern for their toxicity. Among the products used as health supplements are products that contain lactic acid bacteria. This project studied the acute and subacute toxicity of a product containing minerals, herbs, vitamins and live lactic acid bacteria, on Sprague- Dawley rats. Acute toxicity was tested 24 hours after a single dose and subacute toxicity was studied 24 hours after 7 days of daily dosing. The parameters that were studied were alanine aminotransferase (AL T,SGPT), aspartate aminotransferase (AST, SGOT), serum urea, ratios of weight of kidney and liver weight to body weight and percentage changes in body weights. The contents of capsules of the product (6, 8 or lO capsules for acute studies and 6, 10 and 12 for subacute studies) were mixed with corn oil and fed orally to rats. Control rats were fed with corn oil alone. In the acute studies, the level of ALT in the rats treated with the contents of the capsule was lower than controls. There were no significant changes in the other parameters of the rats in the treatment groups as compared to controls. There were no significant differences in all the parameters between rats in the treatment groups as compared to controls in the subacute studies. Sprague-Dawley rats fed with high doses of the product did not show signs of toxicity in the parameters that were studied.

Matched MeSH terms: Bacteria
Fulltext An In Vitro Study On The Anti-Adherence Properties Of Mouthrinses Containing Chlorhexidene Gluconate And Hexitidine

Fathilah, A.R., Othman, Y., Rahim, Z.H.A.

Ann Dent, 1999;6(1):-.
MyJurnal

Chlorhexidine gluconate and hexitidine have been used in many oral health care products as antiplaque and antigingivitis agents. Based on the clinical observations and the plaque and gingivitis scores, chlorhexidine gluconate has been reported to be a better agent. In this study, the anti-adherence properties of chlorhexidine gluconate and hexitidine on individual bacteria strains isolated from a 3-hour plaque (Streptococcus sanguis, Streptococcus mitis 1 and Actinomyces sp.) and on a whole 6-hour plaque culture were determined and compared. The study showed that chlorhexidine gluconate inhibited almost 100 % the adherence of the individual bacteria strains and 87.7 % the adherence of a whole 6-hour plaque culture to the saliva-coated glass surface. Hexitidine appeared to be more selective in its effect. It was shown to inhibit the adherence of S. sanguis and Actinomyces sp. to saliva-coated glass surface by 86.5 % and 51.4 % respectively. Its effect on the S. mitis 1 strains is comparable to that of a whole 6-hour plaque culture where inhibition to adherence were less than 4 % for both.

Matched MeSH terms: Bacteria
Fulltext Lactic Acid Bacteria Is Beneficial For Oral Aphtous Ulcerations - A Preliminary Report

Hashim, B.Y., Rahman, R.A., Philip, K.

Ann Dent, 1999;6(1):-.
MyJurnal

Recurrent aphthous ulcers of the mouth are difficult to treat because of no known definite aetiology. This paper presents the use of lactic acid bacteria thought to modulate the host immune response to affect improvements in the disease. Twenty-five patients with the disease were treated with 6 lactic bacteria capsules (in the form of OMX capsules) daily for a period of six months, and their responses were evaluated. Seventeen patients (73.9%) became free of the disease six months later, while 6 (26.1 %) experienced very dramatic improvements. Two patients were lost to follow-up. It is concluded that lactic acid bacteria is beneficial in the treatment of recurrent aphthous ulcers of the mouth.

Matched MeSH terms: Bacteria; Bacterial Capsules
Fulltext Polymerase Chain Reaction (PCR) Techniques For The Identification Of Uncultivable Oral Microorganisms

Himratul-Aznita, W.H.

Ann Dent, 2001;8(1):-.
MyJurnal

Until today there are still a high percentage of oral microorganisms have not been identified due to inability to isolate using the cultural method. However, identification of uncultivable microorganisms associated with disease will permits clinicians for a more accurate diagnosis, treatment and preventive measures. Unculturable microorganisms are also involved in disease and may account for treatment failure since their susceptibility to antimicrobial agents would be unknown. Thus, the opportunity for a rational approach to the treatment of disease relies on the state of knowledge concerning its aetiology and pathogenesis. Recently developed molecular methods have made it possible to characterise mixed microflora in their entirety, including the substantial numbers of unculturable bacteria. The development of rapid molecular methods like PCR provides a reliable identification of unculturable microorganisms. This paper will review the current literature regarding the PCR techniques used to identify uncultivable oral microflora.

Matched MeSH terms: Bacteria
Fulltext In vitro activity of ceftazidime-avibactam and comparators against Gram-negative bacterial isolates collected in the Asia-Pacific region as part of the INFORM program (2015-2017)

Ko WC, Stone GG

Ann Clin Microbiol Antimicrob, 2020 Apr 01;19(1):14.
PMID: 32238155 DOI: 10.1186/s12941-020-00355-1

BACKGROUND: Antimicrobial resistance among nosocomial Gram-negative pathogens is a cause for concern in the Asia-Pacific region. The aims of this study were to measure the rates of resistance among clinical isolates collected in Asia-Pacific countries, and to determine the in vitro antimicrobial activities of ceftazidime-avibactam and comparators against these isolates.
METHODS: CLSI broth microdilution methodology was used to determine antimicrobial activity and EUCAST breakpoints version 9.0 were used to determine rates of susceptibility and resistance. Isolates were also screened for the genes encoding extended-spectrum β-lactamases (ESBLs) or carbapenemases (including metallo-β-lactamases [MBLs]).
RESULTS: Between 2015 and 2017, this study collected a total of 7051 Enterobacterales isolates and 2032 Pseudomonas aeruginosa isolates from hospitalized patients in Australia, Japan, South Korea, Malaysia, the Philippines, Taiwan, and Thailand. In the Asia-Pacific region, Enterobacterales isolates that were ESBL-positive, carbapenemase-negative (17.9%) were more frequently identified than isolates that were carbapenemase-positive, MBL-negative (0.7%) or carbapenemase-positive, MBL-positive (1.7%). Multidrug-resistant (MDR) isolates of P. aeruginosa were more commonly identified (23.4%) than isolates that were ESBL-positive, carbapenemase-negative (0.4%), or carbapenemase-positive, MBL-negative (0.3%), or carbapenemase-positive, MBL-positive (3.7%). More than 90% of all Enterobacterales isolates, including the ESBL-positive, carbapenemase-negative subset and the carbapenemase-positive, MBL-negative subset, were susceptible to amikacin and ceftazidime-avibactam. Among the carbapenemase-positive, MBL-positive subset of Enterobacterales, susceptibility to the majority of agents was reduced, with the exception of colistin (93.4%). Tigecycline was active against all resistant subsets of the Enterobacterales (MIC90, 1-4 mg/L) and among Escherichia coli isolates, > 90% from each resistant subset were susceptible to tigecycline. More than 99% of all P. aeruginosa isolates, including MDR isolates and the carbapenemase-positive, MBL-positive subset, were susceptible to colistin.
CONCLUSIONS: In this study, amikacin, ceftazidime-avibactam, colistin and tigecycline appear to be potential treatment options for infections caused by Gram-negative pathogens in the Asia-Pacific region.

Matched MeSH terms: Gram-Negative Bacteria
Contact lens-related infectious keratitis in Malaysia

Reddy SC, Tajunisah I

Ann Ophthalmol (Skokie), 2008;40(1):39-44.
PMID: 18556981

Fifty-six contact lens-related corneal ulcers (central in 32; hypopyon in 24 and stromal abscess in 6) were studied. Culture was positive in 78.9%. Corneal ulcers healed with intense antibiotic therapy in nearly all patients. Increased awareness of lens care/disinfection and frequent replacement of storage cases and solution, and early detection of pathogens and intensive appropriate antibiotic therapy are key points in management.

Matched MeSH terms: Anti-Bacterial Agents/therapeutic use; Bacteria/isolation & purification; Eye Infections, Bacterial/drug therapy; Eye Infections, Bacterial/microbiology*
Neonatal septicaemia in Kelantan, Malaysia

Choo KE, Wan Ariffin WA, Chua SP

Ann Acad Med Singap, 1988 Jul;17(3):438-42.
PMID: 3218934

A retrospective study of 84 cases of neonatal septicaemia admitted into a neonatal unit in a rural area of Malaysia for 1 year between 1st September 1985 to 31st August 1986 was carried out to determine the spectrum of micro-organisms and predisposing factors in relation to early and late onset septicaemia. The incidence of neonatal septicaemia was 2.13 per 1,000 live-births per year and the case fatality was 41.7% with higher case fatality in those who were premature, those who presented as early onset and those who had gram negative septicaemia. The mean age of onset of septicaemia was 7.8 days (range from 2 hours to 27 days). Forty four (52%) neonates had early onset septicaemia with mean age of onset at 2.7 days; forty (48%) neonates had late onset septicaemia presenting at 13.6 days of life. Gram negative organisms such as Klebsiella, Pseudomonas, sp., E. coli and Streptococcus, especially group B Streptococcus were the major organisms in the early onset septicaemia. Staphylococcus aureus and Staphylococcus epidermidis were the major organisms responsible for the late onset septicaemia. Obstetrical factors played an important role in early onset septicaemia. Prematurity was the most common predisposing factor. Invasive diagnostic and therapeutic procedures including surgery highlighted once again the importance of these procedures in predisposing the newborn to infection.

Matched MeSH terms: Bacteria/isolation & purification
Fulltext Bioactive Compounds from the Bornean Endemic Plant Goniothalamus longistipetes

Teo SP, Bhakta S, Stapleton P, Gibbons S

Antibiotics (Basel), 2020 Dec 16;9(12).
PMID: 33339285 DOI: 10.3390/antibiotics9120913

The present study aimed to screen plants for bioactive compounds with potential antibacterial activities. In our efforts to evaluate plants from Borneo, we isolated and elucidated the structures of four natural products from the bioactive fraction of a chloroform extract of Goniothalamus longistipetes using various chromatographic and spectroscopic techniques. The bioactive compounds were identified as a known styryllactone, (+)-altholactone ((2S,3R,3aS,7aS)-3-hydroxy-2-phenyl-2,3,3a,7a-tetrahydrobenzo-5(4H)-5-one) (1), a new styryllactone, (2S,3R,3aS,7aS)-3-hydroxy-2-phenyl-2,3,3a,7a-tetrahydrobenzo-5(4H)-5-one) (2) as well as a new alkaloid, 2,6-dimethoxyisonicotinaldehyde (3) and a new alkenyl-5-hydroxyl-phenyl benzoic acid (4). 1 and 4 showed broad-spectrum anti-bacterial activities against Gram-positive and Gram-negative bacteria as well as acid-fast model selected for this study. Compound 2 only demonstrated activities against Gram-positive bacteria whilst 3 displayed selective inhibitory activities against Gram-positive bacterial strains. Additionally, their mechanisms of anti-bacterial action were also investigated. Using Mycobacterium smegmatis as a fast-growing model of tubercle bacilli, compounds 1, 2 and 4 demonstrated inhibitory activities against whole-cell drug efflux and biofilm formation; two key intrinsic mechanisms of antibiotic resistance. Interestingly, the amphiphilic compound 4 exhibited inhibitory activity against the conjugation of plasmid pKM101 in Escherichia coli using a plate conjugation assay. Plasmid conjugation is a mechanism by which Gram-positive and Gram-negative-bacteria acquire drug resistance and virulence. These results indicated that bioactive compounds isolated from Goniothalamus longistipetes can be potential candidates as 'hits' for further optimisation.

Matched MeSH terms: Anti-Bacterial Agents; Bacteria; Gram-Negative Bacteria; Gram-Positive Bacteria
Fulltext Exploring Cefiderocol Resistance Mechanisms in Burkholderia pseudomallei

Hall CM, Somprasong N, Hagen JP, Nottingham R, Sahl JW, Webb JR, et al.

Antimicrob Agents Chemother, 2023 Jun 15;67(6):e0017123.
PMID: 37133377 DOI: 10.1128/aac.00171-23

Cefiderocol is a siderophore cephalosporin designed mainly for treatment of infections caused by β-lactam and multidrug-resistant Gram-negative bacteria. Burkholderia pseudomallei clinical isolates are usually highly cefiderocol susceptible, with in vitro resistance found in a few isolates. Resistance in clinical B. pseudomallei isolates from Australia is caused by a hitherto uncharacterized mechanism. We show that, like in other Gram-negatives, the PiuA outer membrane receptor plays a major role in cefiderocol nonsusceptibility in isolates from Malaysia.

Matched MeSH terms: Gram-Negative Bacteria
Fulltext Epidemiology and molecular characterization of multidrug-resistant Gram-negative bacteria in Southeast Asia

Suwantarat N, Carroll KC

Antimicrob Resist Infect Control, 2016;5:15.
PMID: 27148448 DOI: 10.1186/s13756-016-0115-6

Multidrug-resistant Gram-negative bacteria (MDRGN), including extended-spectrum β-lactamases (ESBLs) and multidrug-resistant glucose-nonfermenting Gram-negative bacilli (nonfermenters), have emerged and spread throughout Southeast Asia.

Matched MeSH terms: Gram-Negative Bacteria; Gram-Negative Bacterial Infections
Rapid degradation of N-3-oxo-acylhomoserine lactones by a Bacillus cereus isolate from Malaysian rainforest soil

Chan KG, Wong CS, Yin WF, Sam CK, Koh CL

Antonie Van Leeuwenhoek, 2010 Oct;98(3):299-305.
PMID: 20376561 DOI: 10.1007/s10482-010-9438-0

A bacterial strain, KM1S, was isolated from a Malaysian rainforest soil sample by using a defined enrichment medium that specifically facilitates selection of quorum quenching bacteria. KM1S was clustered closely to Bacillus cereus by 16S ribosomal DNA sequence analysis. It degraded N-3-oxo-hexanoyl homoserine lactone and N-3-oxo-octanoyl homoserine lactone in vitro rapidly at 4.98 and 6.56 microg AHL h(-1) per 10(9) CFU/ml, respectively, as determined by the Rapid Resolution Liquid Chromatography. The aiiA homologue, encoding an autoinducer inactivation enzyme catalyzing the degradation of N-acylhomoserine lactones, of KM1S was amplified and cloned. Sequence analysis indicated the presence of the motif (106)HXDH-59 amino acids-H(169)-21 amino acids-D(191) for N-acylhomoserine lactone lactonases.

Matched MeSH terms: Gram-Negative Bacteria
Light-activated cytotoxic compounds from Malaysian microorganisms for photodynamic therapy of cancer

Kamal N, Sabaratnam V, Abdullah N, Ho AS, Teo SH, Lee HB

Antonie Van Leeuwenhoek, 2009 Feb;95(2):179-88.
PMID: 19125347 DOI: 10.1007/s10482-008-9301-8

Photodynamic therapy (PDT) is a promising cancer treatment which involves activation of a photosensitizing drug with light to produce reactive oxygen species that kill tumors without causing damage to unirradiated normal tissues. To date, only Photofrin, Foscan and Levulan have been approved for clinical treatment of cancer. Tropical habitats such as those found in Malaysia are attractive sources of new therapeutic compounds as tremendous chemical diversity is found in a large number of plants, animals, marine- and micro-organisms. In our screening program for novel photosensitizers from nature, colorful strains of fungi (from Aspergillus and Penicillium genus) and bacteria (including actinomycetes and photosynthetic bacteria) were collected from various habitats in Peninsular Malaysia, such as coastal soil, peat soil, marine sponges and wastewater ponds. Methanolic extracts from a total of 85 different species were evaluated with a short-term cell viability assay for photo-cytotoxicity, where a promyelocytic leukemia cell-line, HL60 incubated with 20 microg/ml of extracts was irradiated with 9.6 J/cm(2) of a broad spectrum light. Two of these extracts, one from Rhodobacter sphaeroides (PBUM003) and one from Rhodopseudomonas palustris (PBUM001) showed moderate to strong photo-cytotoxicity. Subsequent bioassay guided isolation of the PBUM001 extract yielded known photosensitisers that are based on bacteriochlorophyll-a by comparing their molecular weight data, HPLC profiles and UV-vis absorption spectra with literature values, thereby demonstrating the validity of our screening approach.

Matched MeSH terms: Bacteria/isolation & purification; Bacteria/chemistry*
Fulltext Genome-Centric Metagenomic Insights into the Impact of Alkaline/Acid and Thermal Sludge Pretreatment on the Microbiome in Digestion Sludge

Liang Z, Shi J, Wang C, Li J, Liang D, Yong EL, et al.

Appl Environ Microbiol, 2020 11 10;86(23).
PMID: 32948522 DOI: 10.1128/AEM.01920-20

Pretreatment of waste-activated sludge (WAS) is an effective way to destabilize sludge floc structure and release organic matter for improving sludge digestion efficiency. Nonetheless, information on the impact of WAS pretreatment on digestion sludge microbiomes, as well as mechanistic insights into how sludge pretreatment improves digestion performance, remains elusive. In this study, a genome-centric metagenomic approach was employed to investigate the digestion sludge microbiome in four sludge digesters with different types of feeding sludge: WAS pretreated with 0.25 mol/liter alkaline/acid (APAD), WAS pretreated with 0.8 mol/liter alkaline/acid (HS-APAD), thermally pretreated WAS (thermal-AD), and fresh WAS (control-AD). We retrieved 254 metagenome-assembled genomes (MAGs) to identify the key functional populations involved in the methanogenic digestion process. These MAGs span 28 phyla, including 69 yet-to-be-cultivated lineages, and 30 novel lineages were characterized with metabolic potential associated with hydrolysis and fermentation. Interestingly, functional populations involving carbohydrate digestion were enriched in APAD and HS-APAD, while lineages related to protein and lipid fermentation were enriched in thermal-AD, corroborating the idea that different substrates are released from alkaline/acid and thermal pretreatments. Among the major functional populations (i.e., fermenters, syntrophic acetogens, and methanogens), significant correlations between genome sizes and abundance of the fermenters were observed, particularly in APAD and HS-APAD, which had improved digestion performance.IMPORTANCE Wastewater treatment generates large amounts of waste-activated sludge (WAS), which consists mainly of recalcitrant microbial cells and particulate organic matter. Though WAS pretreatment is an effective way to release sludge organic matter for subsequent digestion, detailed information on the impact of the sludge pretreatment on the digestion sludge microbiome remains scarce. Our study provides unprecedented genome-centric metagenomic insights into how WAS pretreatments change the digestion sludge microbiomes, as well as their metabolic networks. Moreover, digestion sludge microbiomes could be a unique source for exploring microbial dark matter. These results may inform future optimization of methanogenic sludge digestion and resource recovery.

Matched MeSH terms: Bacteria/genetics*; Bacteria/isolation & purification
Fulltext Temporal variation of bacterial respiration and growth efficiency in tropical coastal waters

Lee CW, Bong CW, Hii YS

Appl Environ Microbiol, 2009 Dec;75(24):7594-601.
PMID: 19820145 DOI: 10.1128/AEM.01227-09

We investigated the temporal variation of bacterial production, respiration, and growth efficiency in the tropical coastal waters of Peninsular Malaysia. We selected five stations including two estuaries and three coastal water stations. The temperature was relatively stable (averaging around 29.5 degrees C), whereas salinity was more variable in the estuaries. We also measured dissolved organic carbon and nitrogen (DOC and DON, respectively) concentrations. DOC generally ranged from 100 to 900 microM, whereas DON ranged from 0 to 32 microM. Bacterial respiration ranged from 0.5 to 3.2 microM O2 h(-1), whereas bacterial production ranged from 0.05 to 0.51 microM C h(-1). Bacterial growth efficiency was calculated as bacterial production/(bacterial production + respiration), and ranged from 0.02 to 0.40. Multiple correlation analyses revealed that bacterial production was dependent upon primary production (r2 = 0.169, df = 31, and P < 0.02) whereas bacterial respiration was dependent upon both substrate quality (i.e., DOC/DON ratio) (r2 = 0.137, df = 32, and P = 0.03) and temperature (r2 = 0.113, df = 36, and P = 0.04). Substrate quality was the most important factor (r2 = 0.119, df = 33, and P = 0.04) for the regulation of bacterial growth efficiency. Using bacterial growth efficiency values, the average bacterial carbon demand calculated was from 5.30 to 11.28 microM C h(-1). When the bacterial carbon demand was compared with primary productivity, we found that net heterotrophy was established at only two stations. The ratio of bacterial carbon demand to net primary production correlated significantly with bacterial growth efficiency (r2 = 0.341, df = 35, and P < 0.001). From nonlinear regression analysis, we found that net heterotrophy was established when bacterial growth efficiency was <0.08. Our study showed the extent of net heterotrophy in these waters and illustrated the importance of heterotrophic microbial processes in coastal aquatic food webs.

Matched MeSH terms: Bacteria/growth & development*; Bacterial Physiological Phenomena*
Fulltext Impact of logging and forest conversion to oil palm plantations on soil bacterial communities in Borneo

Lee-Cruz L, Edwards DP, Tripathi BM, Adams JM

Appl Environ Microbiol, 2013 Dec;79(23):7290-7.
PMID: 24056463 DOI: 10.1128/AEM.02541-13

Tropical forests are being rapidly altered by logging and cleared for agriculture. Understanding the effects of these land use changes on soil bacteria, which constitute a large proportion of total biodiversity and perform important ecosystem functions, is a major conservation frontier. Here we studied the effects of logging history and forest conversion to oil palm plantations in Sabah, Borneo, on the soil bacterial community. We used paired-end Illumina sequencing of the 16S rRNA gene, V3 region, to compare the bacterial communities in primary, once-logged, and twice-logged forest and land converted to oil palm plantations. Bacteria were grouped into operational taxonomic units (OTUs) at the 97% similarity level, and OTU richness and local-scale α-diversity showed no difference between the various forest types and oil palm plantations. Focusing on the turnover of bacteria across space, true β-diversity was higher in oil palm plantation soil than in forest soil, whereas community dissimilarity-based metrics of β-diversity were only marginally different between habitats, suggesting that at large scales, oil palm plantation soil could have higher overall γ-diversity than forest soil, driven by a slightly more heterogeneous community across space. Clearance of primary and logged forest for oil palm plantations did, however, significantly impact the composition of soil bacterial communities, reflecting in part the loss of some forest bacteria, whereas primary and logged forests did not differ in composition. Overall, our results suggest that the soil bacteria of tropical forest are to some extent resilient or resistant to logging but that the impacts of forest conversion to oil palm plantations are more severe.

Matched MeSH terms: Bacteria/classification*; Bacteria/isolation & purification*; DNA, Bacterial/genetics; DNA, Bacterial/chemistry
Identification and characterization of the yellow pigment synthesized by Cupriavidus sp. USMAHM13

Ramachandran H, Iqbal MA, Amirul AA

Appl Biochem Biotechnol, 2014 Sep;174(2):461-70.
PMID: 25099372 DOI: 10.1007/s12010-014-1080-2

Microbial pigments are gaining intensive attention due to increasing awareness of the toxicity of synthetic colours. In this study, a novel polymer-producing bacterium designated as Cupriavidus sp. USMAHM13 was also found to produce yellow pigment when cultivated in nutrient broth. Various parameters such as temperature, pH and ratio of culture volume to flask volume were found to influence the yellow pigment production. UV-Visible, Fourier transform infrared and (13)C-nuclear magnetic resonance analyses revealed that the crude yellow pigment might probably represent new bioactive compound in the carotenoid family. The crude yellow pigment also exhibited a wide spectrum of antimicrobial activity against Gram-negative and Gram-positive bacteria with their inhibition zones and minimal inhibitory concentrations ranged from 25 to 38 mm and from 0.63 to 2.5 mg/ml, respectively. To the best of our knowledge, this is the first report on the identification and characterization of yellow pigment produced by bacterium belonging to the genus Cupriavidus.

Matched MeSH terms: Gram-Negative Bacteria/drug effects; Gram-Positive Bacteria/drug effects
Environmental degradation of microbial polyhydroxyalkanoates and oil palm-based composites

Salim YS, Sharon A, Vigneswari S, Mohamad Ibrahim MN, Amirul AA

Appl Biochem Biotechnol, 2012 May;167(2):314-26.
PMID: 22544728 DOI: 10.1007/s12010-012-9688-6

This paper investigates the degradation of polyhydroxyalkanoates and its biofiber composites in both soil and lake environment. Time-dependent changes in the weight loss of films were monitored. The rate of degradation of poly(3-hydroxybutyrate) [P(3HB)], poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-23 mol% 4HB)] and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate) [P(3HB-co-9 mol% 3HV-co-19 mol% 4HB)] were investigated. The rate of degradation in the lake is higher compared to that in the soil. The highest rate of degradation in lake environment (15.6% w/w week(-1)) was observed with P(3HB-co-3HV-co-4HB) terpolymer. Additionally, the rate of degradation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-38 mol% 3HV)] was compared to PHBV biofiber composites containing compatibilizers and empty fruit bunch (EFB). Here, composites with 30% EFB displayed the highest rate of degradation both in the lake (25.6% w/w week(-1)) and soil (15.6% w/w week(-1)) environment.

Matched MeSH terms: Bacteria/metabolism*; Bacteria/chemistry
A Review on Psychrophilic β-D-Galactosidases and Their Potential Applications

Reddy LJ, Kumar PS, Pandrangi SL, Chikati R, Srinivasulu C, John A, et al.

Appl Biochem Biotechnol, 2023 Apr;195(4):2743-2766.
PMID: 36422804 DOI: 10.1007/s12010-022-04215-w

The majority of the Earth's ecosystem is frigid and frozen, which permits a vast range of microbial life forms to thrive by triggering physiological responses that allow them to survive in cold and frozen settings. The apparent biotechnology value of these cold-adapted enzymes has been targeted. Enzymes' market size was around USD 6.3 billion in 2017 and will witness growth at around 6.8% CAGR up to 2024 owing to shifting consumer preferences towards packaged and processed foods due to the rising awareness pertaining to food safety and security reported by Global Market Insights (Report ID-GMI 743). Various firms are looking for innovative psychrophilic enzymes in order to construct more effective biochemical pathways with shorter reaction times, use less energy, and are ecologically acceptable. D-Galactosidase catalyzes the hydrolysis of the glycosidic oxygen link between the terminal non-reducing D-galactoside unit and the glycoside molecule. At refrigerated temperature, the stable structure of psychrophile enzymes adjusts for the reduced kinetic energy. It may be beneficial in a wide variety of activities such as pasteurization of food, conversion of biomass, biological role of biomolecules, ambient biosensors, and phytoremediation. Recently, psychrophile enzymes are also used in claning the contact lens. β-D-Galactosidases have been identified and extracted from yeasts, fungi, bacteria, and plants. Conventional (hydrolyzing activity) and nonconventional (non-hydrolytic activity) applications are available for these enzymes due to its transgalactosylation activity which produce high value-added oligosaccharides. This review content will offer new perspectives on cold-active β-galactosidases, their source, structure, stability, and application.

Matched MeSH terms: Bacteria/metabolism

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