A Case-Control Study of Risk Factors for Bovine Brucellosis Seropositivity in Peninsular Malaysia

Bovine brucellosis was first reported in Peninsular Malaysia in 1950. A subsequent survey conducted in the country revealed that the disease was widespread. Current knowledge on the potential risk factors for brucellosis occurrence on cattle farms in Malaysia is lacking. Therefore, we conducted a case-control study to identify the potential herd-level risk factors for bovine brucellosis occurrence in four states in the country, namely Kelantan, Pahang, Selangor and Negeri Sembilan. Thirty-five cases and 36 controls of herds were selected where data on farm management, biosecurity, medical history and public health were collected. Multivariable logistic regression identified that Brucella seropositive herds were more likely to; have some interaction with wildlife (OR 8.9, 95% CI = 1.59–50.05); originated from farms where multiple species such as buffalo/others (OR 41.8, 95% CI = 3.94–443.19) and goat/sheep (OR 8.9, 95%Cl = 1.10–71.83) were reared, practice extensive production system (OR 13.6, 95% CI 1.31–140.24) and have had episodes of abortion in the past (OR 51.8, 95% CI = 4.54–590.90) when compared to seronegative herds. Considering the lack of information on the epidemiology of bovine brucellosis in peninsular Malaysia and absence of information on preventing the inception or spread of the disease, this report could contribute to the on-going area-wise national brucellosis eradication program.     

The Staphylococcus aureus surface protein IsdA mediates resistance to innate defenses of human skin

Resistance to human skin innate defenses is crucial for survival and carriage of Staphylococcus aureus, a common cutaneous pathogen and nasal colonizer. Free fatty acids extracted from human skin sebum possess potent antimicrobial activity against S. aureus. The mechanisms by which S. aureus overcomes this host defense during colonization remain unknown. Here, we show that S. aureus IsdA, a surface protein produced in response to the host, decreases bacterial cellular hydrophobicity rendering them resistant to bactericidal human skin fatty acids and peptides. IsdA is required for survival of S. aureus on live human skin. Reciprocally, skin fatty acids prevent the production of virulence determinants and the induction of antibiotic resistance in S. aureus and other Gram-positive pathogens. A purified human skin fatty acid was effective in treating systemic and topical infections of S. aureus suggesting that our natural defense mechanisms can be exploited to combat drug-resistant pathogens.     

Recent advances in production of succinic acid from lignocellulosic biomass

Production of succinic acid via separate enzymatic hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) are alternatives and are environmentally friendly processes. These processes have attained considerable positions in the industry with their own share of challenges and problems. The high-value succinic acid is extensively used in chemical, food, pharmaceutical, leather and textile industries and can be efficiently produced via several methods. Previously, succinic acid production via chemical synthesis from petrochemical or refined sugar has been the focus of interest of most reviewers. However, these expensive substrates have been recently replaced by alternative sustainable raw materials such as lignocellulosic biomass, which is cheap and abundantly available. Thus, this review focuses on succinic acid production utilizing lignocellulosic material as a potential substrate for SSF and SHF. SSF is an economical single-step process which can be a substitute for SHF — a two-step process where biomass is hydrolyzed in the first step and fermented in the second step. SSF of lignocellulosic biomass under optimum temperature and pH conditions results in the controlled release of sugar and simultaneous conversion into succinic acid by specific microorganisms, reducing reaction time and costs and increasing productivity. In addition, main process parameters which influence SHF and SSF processes such as batch and fed-batch fermentation conditions using different microbial strains are discussed in detail.     

LC-MS/MS-based metabolites of Eurycoma longifolia (Tongkat Ali) in Malaysia (Perak and Pahang)

A number of three LC-MS/MS hybrid systems (QTof, TripleTof and QTrap) has been used to profile small metabolites (m/z 100-1000) and to detect the targeted metabolites such as quassinoids, alkaloids, triterpene and biphenylneolignans from the aqueous extracts of Eurycoma longifolia. The metabolite profiles of small molecules showed four significant clusters in the principle component analysis for the aqueous extracts of E. longifolia, which had been collected from different geographical terrains (Perak and Pahang) and processed at different extraction temperatures (35°C and 100°C). A small peptide of leucine (m/z 679) and a new hydroxyl methyl β-carboline propionic acid have been identified to differentiate E. longifolia extracts that prepared at 35°C and 100°C, respectively. From the targeted metabolites identification, it was found that 3,4?-dihydroeurycomanone (quassinoids) and eurylene (squalene-type triterpene) could only be detected in the Pahang extract, whereas canthin-6-one-3N-oxide could only be detected in the Perak extract. Overall, quassinoids were present in the highest concentration, particularly eurycomanone and its derivatives compared to the other groups of metabolites. However, the concentration of canthin-6-one and β-carboline alkaloids was significantly increased when the roots of the plant samples were extracted at 100°C.     

Gelling properties of soybean beta-conglycinin having different subunit compositions

The effects of protein concentration, and heating temperature and time on the gelling properties of soybean beta-conglycinin (7S globulins) lacking the alpha or alpha' subunit were compared with those of 7S containing all three subunits (alpha, alpha', and beta) to determine whether each subunit contributes equally. In most of the conditions, the relative order of gel hardness was alpha'-lacking > 7S > alpha-lacking. From Fourier transform infrared studies, the secondary structure change after heating was very similar among the three samples; thus, the secondary structural change is not the reason for the differences in gel hardness. By using scanning electron microscopy, we observed differences in strand thickness and the density of the gel network among the three samples. These differences correlated well with the differences in gel hardness.     

DNA Tetrominoes: The Construction of DNA Nanostructures Using Self-Organised Heterogeneous Deoxyribonucleic Acids Shapes

The unique programmability of nucleic acids offers alternative in constructing excitable and functional nanostructures. This work introduces an autonomous protocol to construct DNA Tetris shapes (L-Shape, B-Shape, T-Shape and I-Shape) using modular DNA blocks. The protocol exploits the rich number of sequence combinations available from the nucleic acid alphabets, thus allowing for diversity to be applied in designing various DNA nanostructures. Instead of a deterministic set of sequences corresponding to a particular design, the protocol promotes a large pool of DNA shapes that can assemble to conform to any desired structures. By utilising evolutionary programming in the design stage, DNA blocks are subjected to processes such as sequence insertion, deletion and base shifting in order to enrich the diversity of the resulting shapes based on a set of cascading filters. The optimisation algorithm allows mutation to be exerted indefinitely on the candidate sequences until these sequences complied with all the four fitness criteria. Generated candidates from the protocol are in agreement with the filter cascades and thermodynamic simulation. Further validation using gel electrophoresis indicated the formation of the designed shapes. Thus, supporting the plausibility of constructing DNA nanostructures in a more hierarchical, modular, and interchangeable manner.     

Estimation of the sensitivity to photoinhibition in Striga hermonthica-infected sorghum

Sensitivity to photoinhibition was assessed in sorghum infectedwith the angiosperm root parasite Striga her-monthica and inuninfected sorghum plants, at four times during the developmentof the host-parasite association. Photoinhibition was inducedby exposing either leaf discs or intact leaves to a photosyntheticphoton flux density of 2000 µmol m^–2 s^–1 for4 h. The inhibition of apparent quantum yield (_a) and photosynthesisin high light (A₁₅₀₀) were assessed in leaf discs using an oxygenelectrode and the recovery of these from photoinhibition wasfollowed in intact leaves using an infra-red gas analyser. Fromsoon after attachment of the parasite, infected sorghum plantshad a lower A₁₅₀₀. During the period when Striga induced a loweringof A₁₅₀₀, _a was more sensitive to photoinhibition in Striga-infectedplants. However, at the same time, the high-light-induced inhibitionof A₁₅₀₀ was similar in Striga-infected and uninfected plants.Recovery of both _a and A₁₅₀₀ was incomplete after 6 h and thetime-course of recovery was similar in Striga-infected and uninfectedplants. The results indicate that Striga-infected plants weremore sensitive to photoinhibition and that photoinhibition wasprimarily due to damage to electron transport/photo-phosphorylationand not disablement of the recovery processes. Key words: Photoinhibition, quantum yield, recovery from photoinhibition, parasitic plants     

Monoclonal antibody production: viability improvement of RC1 hybridoma cell in different types of bioreactor

The study was done to improve the viability of the RC1 hybridoma cell in order to produce more amount of monoclonal antibody (mAb). By using the optimized media, the cell had been cultured in two bioreactor systems which were the MiniPerm and Stirred Tank bioreactor (ST bioreactor), and the results were compared to the one obtained by using the T-Flask bioreactor which was used as a standard. The results showed that the ST bioreactor was able to improve the viability of the cell to the value of 91.8% which was a little bit better than the one obtained by the MiniPerm bioreactor (88.6%) and far better than that of achieved by the T-Flask bioreactor (76.4%). This was well correlated with the good growth performance of the cell in the ST bioreactor with the specific growth rate (μ) value of 0.0289 h⁻¹ followed by MiniPerm bioreactor with the value of 0.0243 h⁻¹ and then the T-Flask with the value of 0.0151 h⁻¹. The low value of doubling time (t _d ) obtained in the ST bioreactor (24 h) compared to the one obtained in the MiniPerm (29 h) and T-Flask bioreactor (46 h) had also contributed to the higher value of cell viability. As a result a higher concentration of mAb was able to be produced by the ST bioreactor (0.42 g l⁻¹) compared to that of the MiniPerm (0.37 g l⁻¹) and T-Flask bioreactor (0.23 g l⁻¹).     

Recent progress on the development of antibiotics from the genus <Emphasis Type="Italic">Micromonospora</Emphasis>

The emergence of a large number of antimicrobialresistant organisms is a cause for concern. Nature is historically the source of drugs; indeed a considerable number of drugs have been developed from microorganisms, and are now used daily in the treatment of infectious diseases. However, the introduction to the pharmaceutical market of new therapeutic molecules has decreased during the last two decades. In this review, the genus Micromonospora is proposed as a biofactory for production of new antibiotics. The genus Micromonospora has been investigated extensively and more than 100 antibiotics have been isolated from diverse Micromonospora strains. In addition, recent developments in analytical, biological and bioinformatics screening tools used in the discovery of new therapeutic compounds are described. It may be possible to revive formerly used antibiotics produced by Micromonospora and study of this genus may facilitate discovery of novel bioactive molecules.     

Design of interacting multi-stable nucleic acids for molecular information processing

Despite an exponential increase in computing power over the past decades, present information technology falls far short of expectations in areas such as cognitive systems and micro robotics. Organisms demonstrate that it is possible to implement information processing in a radically different way from what we have available in present technology, and that there are clear advantages from the perspective of power consumption, integration density, and real-time processing of ambiguous data. Accordingly, the question whether the current silicon substrate and associated computing paradigm is the most suitable approach to all types of computation has come to the fore. Macromolecular materials, so successfully employed by nature, possess uniquely promising properties as an alternate substrate for information processing. The two key features of macromolecules are their conformational dynamics and their self-assembly capabilities. The purposeful design of macromolecules capable of exploiting these features has proven to be a challenge, however, for some groups of molecules it is increasingly practicable. We here introduce an algorithm capable of designing groups self-assembling of nucleic acid molecules with multiple conformational states. Evaluation using natural and artificially designed nucleic acid molecules favours this algorithm significantly, as compared to the probabilistic approach. Furthermore, the thermodynamic properties of the generated candidates are within the same approximation as the customised trans-acting switching molecules reported in the laboratory.