Identifying climate refugia for 30 Australian rainforest plant species,from the last glacial maximum to 2070

Landscape Ecology - Climate refugia—areas that remain suitable for species during periods of climate disruption—have played an important role in species persistence over time....     

Cohort analysis on a freshwater fish Osteochilus hasselti C. & V. (Cyprinidae) at Bukit Merah Reservoir,Malaysia

An earlier cohort analysis using catch-at-length data (for the period May 1979–April 1980) on the stock of Osteochilus hasselti C. & V. computes statistics on: (1) the total stock at the start of the cohort (N = 22.7 × 10⁵) (these stock numbers decrease progressively at successive lengths, in a steady state and assuming constant natural mortality rate, M = 2.1); (2) catch numbers in a cohort totalling 780 940 individuals; (3) the exploitation rate of the cohort of E = 0.34, suggesting moderate exploitation of the species at Bukit Merah Reservoir, Malaysia.However, the validity of cohort analysis on a species exploited at a very early age depends on the input value of the variables natural mortality rate (M), fishing mortality rate of terminal largest fish (F_ter), and growth parameters (L_∞, K). Because of the methodological difficulties in estimation and verification of M, F_ter and K values of O. hasselti, a range of values of input variables is adopted for comparison. The effect of the variability of M values (0.5, 1.0, 1.5 and 2.5) on the computation results of smaller size-class fishes N_L is significantly different from that based on M = 2.1, showing a much lower population size.The variability of input values of F_ter (range 0.5–2.5) and K (0.28–2.62) is tested on their effects on the population size of recruits. The combined effect of M and K in the relationship of $\text{M}\text{K}$ ranging from 0.8 to 2.5 is varied to decide the possible values of K. In general, the different input values of M, F_ter and K result in lower estimates of the population size of recruits, N_r This is about 28% lower than N_r = 22.7 × 10⁵ when M = F_ter = 2.1 and K = 1.15. With an inherent computational bias, the population size of N_r = 22.7 × 10⁵ is probably an under-estimate, but it is both reasonable and biologically possible for O. hasselti at Bukit Merah Reservoir, Malaysia, since the input variables are generated from representative length composition data of commercial catches and tagging data.     

Multiplex PCR genotyping for five bacterial blight resistance genes applied to marker‐assisted selection in rice (Oryza sativa)

Bacterial blight (BB) is the most economically damaging disease of rice in Asia and other parts of the world. In this study, a multiplex PCR genotyping method was developed to simultaneously identify genotypes of five BB resistance genes, Xa4, xa5, Xa7, xa13 and Xa21. The resistance R alleles were amplified using five functional markers (FMs) to generate amplicons of 217, 103, 179, 381 and 595 bp in IRBB66. Amplicons of 198, 107, 87, 391 and 467 bp corresponded to susceptible alleles in Taiwanese japonica rice cultivars. In backcross breeding programmes, the multiplex PCR assay was integrated into selection from a population using BB resistance donor IRBB66 crossed to rice cultivar ‘Tainung82’. Two plants with homozygosity for Xa4, xa5, Xa7, xa13 and Xa21 were selected from 1100 BC₂F₂ plants. In addition, the five BB resistance genes were also accurately identified in F₂ populations. This multiplex PCR method provides a rapid and efficient method for detecting various BB resistance genes, which will assist in pyramiding genes to improve durability of BB resistance in Taiwanese elite rice cultivars.     

Development of new assessment methods for Acropora coral recruitment using coral settlement devices and holes of marine block

We developed new assessment methods for Acropora coral recruitment using coral settlement devices (CSDs) and holes of a marine block. Both devices were deployed in situ before mass spawning of Acropora corals. The CSDs were sampled after 3–4 months of spawning to measure early recruitment, whereas holes of the marine block were observed underwater or MB was sampled to observe holes after 1 year of spawning to measure the recruitment. By combining the results, we would know the recruitment (visually identified underwater) in reefs, including the amount of early recruitment (identified by stereomicroscopic methods), and the environmental condition of the coral reef. These results would help to predict the future of a reef. Nagura Bay had a high early Acropora recruitment; however, due to competition with algae and sedimentation, the recruitment of juvenile corals was extremely low. The reef would possibly be healthy and sustainable at sites where both the early recruitment and recruitment are high. However, if both are low, the reef will be in a critical condition where urgent restoration will be required.     

Impact of vitronectin concentration and surface properties on the stable propagation of human embryonic stem cells

The standard method for culturing human embryonic stem cells (hESC) uses supporting feeder layers of cells or an undefined substrate, Matrigel(?), which is a basement membrane extracted from murine sarcoma. For stem cell therapeutic applications, a superior alternative would be a defined, artificial surface that is based on immobilized human plasma vitronectin (VN), which is an adhesion-mediating protein. Therefore, VN adsorbed to diverse polymer surfaces was explored for the continuous propagation of hESC. Cells propagated on VN-coated tissue culture polystyrene (TCPS) are karyotypically normal after >10 passages of continuous culture, and are able to differentiate into embryoid bodies containing all three germ layers. Expansion rates and pluripotent marker expression verified that a minimal VN surface density threshold is required on TCPS. Further exploration of adsorbed VN was conducted on polymer substrates with different properties, ranging from hydrophilic to hydrophobic and including cationic and anionic polyelectrolyte coatings. Despite differing surface properties, these substrates adsorbed VN above the required surface density threshold and were capable of supporting hESC expansion for >10 passages. Correlating wettability of the VN-coated surfaces with the response of cultured hESC, higher cell expansion rates and OCT-4 expression levels were found for VN-coated TCPS, which exhibits a water contact angle close to 65°. Importantly, this simple, defined surface matches the performance of the benchmark Matrigel, which is a hydrogel with highly complex composition.     

Bioactive Compounds from Marine Sponges: Fundamentals and Applications

Marine sponges are sessile invertebrates that can be found in temperate, polar and tropical regions. They are known to be major contributors of bioactive compounds, which are discovered in and extracted from the marine environment. The compounds extracted from these sponges are known to exhibit various bioactivities, such as antimicrobial, antitumor and general cytotoxicity. For example, various compounds isolated from Theonella swinhoei have showcased various bioactivities, such as those that are antibacterial, antiviral and antifungal. In this review, we discuss bioactive compounds that have been identified from marine sponges that showcase the ability to act as antibacterial, antiviral, anti-malarial and antifungal agents against human pathogens and fish pathogens in the aquaculture industry. Moreover, the application of such compounds as antimicrobial agents in other veterinary commodities, such as poultry, cattle farming and domesticated cats, is discussed, along with a brief discussion regarding the mode of action of these compounds on the targeted sites in various pathogens. The bioactivity of the compounds discussed in this review is focused mainly on compounds that have been identified between 2000 and 2020 and includes the novel compounds discovered from 2018 to 2021.     

Antimicrobial labelling in Australia: a threat to antimicrobial stewardship?

Antimicrobial resistance is a public health emergency, placing veterinary antimicrobial use under growing scrutiny. Antimicrobial stewardship, through appropriate use of antimicrobials, is a response to this threat. The need for antimicrobial stewardship in Australian veterinary practices has had limited investigation. A 2016 survey undertaken to investigate antimicrobial usage patterns by Australian veterinarians found that antimicrobial dose rates were varied and often inappropriate. Doses of procaine penicillin in horses and cattle were often low, with 68% and 90% of respondents, respectively, reporting doses that were unlikely to result in plasma concentrations above minimum inhibitory concentrations for common equine and bovine pathogens. Frequency of penicillin administration was also often inappropriate. Gentamicin doses in horses were largely appropriate (89% of dose rates appropriate), but 9% of respondents reported twice daily dosing. Amoxycillin and amoxycillin‐clavulanate were administered at the appropriate doses, or above, to dogs and cats by 54% and 70% of respondents, respectively. Here, we explore the potential reasons for inappropriate antimicrobial dose regimens and report that antimicrobial labels often recommend incorrect dose rates and thus may be contributing to poor prescribing practices. Changes to legislation are needed to ensure that antimicrobial drug labels are regularly updated to reflect the dose needed to effectively and safely treat common veterinary pathogens. This will be especially true if changes in legislation restrict antimicrobial use by veterinarians to the uses and doses specified on the label, thus hampering the current momentum towards improved antimicrobial stewardship.