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Understanding the impact of recreational disturbance caused by motor vehicles on waterbirds: a case study from the Bundala Wetland, Sri Lanka
No full textPromotion of recreational access is an important strategy that helps to impart conservation values to wetlands and aids in fostering sustainable employment for local communities who live in close proximity to wildlife habitats. Unregulated recreational vehicles in coastal wetlands can cause detrimental impacts on coastal avifauna. There is a dearth of information especially in the South Asian context on the impact of recreational disturbance to waterbirds that can inform the management of wetland destinations. This study examined the response of selected water birds to motor vehicles using multispecies experimental disturbance trials conducted at Bundala National Park, Sri Lanka; a Ramsar-listed wetland of global importance. The selected species had significantly different sensitivities to disturbance caused by motor vehicles (log-rank test, χ2 = 51.7, P < 0.05). The probability of a bird responding to a moving vehicle parallel to the bird at a distance of 75 m was greater than 0.6 for all selected species (Calidris minuta, Charadrius alexandrinus, Himantopus himantopus, Limosa limosa, Platalea leucorodia and Mycteria leucocephala) except Hydroprogne caspia. Resting birds appeared to be more affected by recreational disturbance when compared to foraging birds. Larger birds (height of adult bird: 80-105 cm) were more sensitive to recreational stimuli, compared to smaller birds (10-20 cm). In general, responses of birds for recreational stimuli, were prominent up to 100 m from the source. Selected waterbirds showed longer response distances in habitats exposed to high vehicle traffic activity suggesting possible habituation of birds to recurring disturbance. Our findings suggest a minimal setback buffer of 100 m needs to be employed to manage recreational disturbance from motor vehicles at Bundala National Park
Ozone efficiency on two Coleopteran insect pests and its effect on quality and germination of barley
Get PDFOzone (O3) is a potential fumigant to control pests in stored grain since it can safely and rapidly auto-decompose without leaving residues. In this study, the efficacy of O3 on all life stages of Rhyzopertha dominica (Fabricius) and Tribolium castaneum (Herbst) in barley and the physiological effects on barley and its quality were investigated. Complete control of all life stages of pests was obtained at 700 ppm for 1440 min of ozone exposure without negatively impacting the contents of soluble protein, moisture content, seed colour, hardness, and the weight of thousand barley seeds. The eggs and pupae of these two insects were the more tolerant stages than their larvae and adults. Prolonged exposure times (40 to 1440 min) and mortality assessment intervals (1, 2, and 7 days) increased O3 efficacy due to the reaction characteristics and delayed toxicity. Aging barley seeds appeared to be more sensitive to prolonged ozone duration than new seeds. A total of 20 and 40 min could promote germination rate, and longer O3 exposure (1440 min) was unfavourable for germination and seedling growth. Thus, it is imperative to select an optimal O3 exposure time to transfer ozone into quality contributors of final products and achieve the desired functional outcomes
Novel microsatellites and investigation of faecal DNA as a non-invasive population monitoring tool for the banded hare-wallaby (Lagostrophus fasciatus)
Get PDFMonitoring programs for populations of small or medium-sized animals often use live-capture or photo-monitoring trapping methods to estimate population size. The banded hare-wallaby (Lagostrophus fasciatus), a small macropodiform marsupial, does not readily enter traps or have individually unique distinguishing physical features and is consequently difficult to monitor using these methods. Isolating DNA from faecal material to obtain individual genotypes is a promising monitoring technique and may present an alternative approach for this species. We developed novel species-specific microsatellite markers and undertook trials to assess faecal DNA degradation in ambient environmental conditions at two locations where this species has been translocated. The quality of DNA yielded from faecal pellets was evaluated through amplification failure and genotyping error rates of microsatellite markers. Error rates were compared for different treatments and exposure duration across multiple individuals. DNA was successfully obtained from all samples and error rates increased with exposure duration, peaking after 14–30 days depending on the site and treatment. The level of solar exposure was the most significant factor affecting degradation rate but both this and exposure duration had significant effects on amplification failure. Analysing DNA obtained from faecal pellets may represent a practical non-invasive method of deriving population estimates for this species and warrants further development
The impact of boron seed priming on seedling establishment, growth, and grain biofortification of mungbean (Vigna radiata L.) in yermosols
Get PDFBoron-deficiency in Yermosols is among the major constraints to mungbean productivity and grain biofortification in Pakistan. However, agronomic strategies such as boron (B) seed priming have potential to improve mungbean yield and grain biofortification. Moreover, deficiency to toxicity range for B is very narrow; therefore, it is pre-requisite to optimize its dose before field evaluation. A wire house experiment was planned out to reconnoiter the impact of seed priming with B on growth and quality of two cultivars of mungbean, i.e., ‘NM-2011’ and ‘NM-2016’. Four different B levels were used as seed priming, i.e., 0.01%, 0.05%, 0.1% and 1.0% B, (borax Na2B4O7.10H2O, 11.5% B) were tested, whereas hydropriming was regarded as control. Seed priming with 0.01% B significantly (p≤0.05) lowered time taken to start germination and time to reach 50% emergence, whereas improved mean emergence time, emergence index, final emergence percentage, number of leaves, dry and fresh weight of root, shoot, and total weight, root length, plant height, chlorophyll contents, number of pods and 100-grain weight, seeds per plant, grain yield per plant, B concentrations in stem and grain, grain protein, carbohydrate and fiber in both cultivars. Boron seed priming proved beneficial under a specific range; however, deficiency (hydropriming) and excess (above 0.01% B) of B were detrimental for mungbean growth and productivity. The cultivar ‘NM-2016’ had significantly (p≤0.05) higher yield due to prominent increase in yield related traits with 0.01% B priming as compared to ‘NM-2011’. In conclusion, B seed priming (0.01% B) seemed a feasible choice for improving mungbean growth, yield related traits and grain-B concentration of mungbean on Yermosols
Clostridioides (Clostridium) difficile in children with diarrhoea in Vietnam
No full textBackground
Clostridioides (Clostridium) difficile commonly causes hospital-acquired infection which can range from mild diarrhoea to life-threatening toxic megacolon and even death. Reports on C. difficile infection (CDI) in Vietnam are limited, so this study was designed to evaluate the prevalence, molecular epidemiology and antimicrobial susceptibility of C. difficile isolated from children with diarrhoea in Vietnam. Infants are often colonised with C. difficile and it was hypothesised that those colonising strains would represent strains of C. difficile circulating in the hospital/region at the time, however, this was not an attempt to determine if C. difficile was the cause of the diarrhoea.
Methods
Diarrhoeal stool samples collected at two children's hospitals in northern Vietnam from October 1, 2020 to February 28, 2021 were transported to Perth, Western Australia, for culture of C. difficile and further investigations on isolates; PCR ribotyping, toxin gene profiling and antimicrobial susceptibility testing.
Results
From these hospitals, 370 diarrhoeal stool samples were collected, most from children aged 1–15 months (71.9%; 266/370). The overall prevalence of C. difficile in stool samples from children aged ≤16 years was 37.8% (140/370) and the highest prevalence was in the 2–12 months age group (52.9%; 74/140). In total, 151 isolates of C. difficile were recovered; the proportion of toxigenic isolates was 16.6% (25/151). Of the 25 toxigenic C. difficile isolates, the toxin gene profiles A+B+CDT− and A−B+CDT− comprised 72% and 28%, respectively. The four most prevalent C. difficile ribotypes (RTs) were QX 011 (25/151), RT 010 (25/151), QX 107 (12/151) and RT 012 (11/151). All isolates were susceptible to vancomycin, metronidazole and fidaxomicin, while there was significant resistance to clindamycin (90.1%), and some to moxifloxacin (6.6%) and rifaximin (3.3%).
Conclusion
The prevalence of C. difficile in children with diarrhoea was high (37.8%) although the proportion of toxigenic strains was comparatively low. The clinical significance of any isolate needs to be determined
A Loop-Mediated Isothermal Amplification (LAMP) Assay Specific to Trichomonas tenax Is Suitable for Use at Point-of-Care
Get PDFTrichomonas tenax is a flagellated protozoan that inhabits the human and canine oral cavity in patients with poor oral hygiene and periodontal disease. The loop-mediated isothermal amplification (LAMP) assay could provide clinicians with a quick, cheap and reliable diagnostic test used for the detection of T. tenax in various settings. In this study, we aimed to develop a LAMP assay that can detect T. tenax with high sensitivity and specificity. A set of LAMP primers were specifically designed to detect the ITS and 5.8S rRNA gene of T. tenax. The newly developed LAMP assay was 1000 times more sensitive than conventional PCR. The limit of detection of the LAMP assay was 10 fg of genomic DNA, or 0.2–1 cell. Moreover, the LAMP assay was specific, resulting in no cross-reaction even with a closely related protozoan T. vaginalis or other microorganisms (Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, and Candida albicans) used. The present LAMP assay can be performed directly without prior DNA extraction, making the assay an easy, fast, cheap, specific and sensitive diagnostic tool for the detection of T. tenax at the point-of-care of both medical and veterinary clinics in developed and developing countries
Efficacy and suitability of liquid ethyl formate for insect pest management
Get PDFThe Australian agricultural industry is critical to the nation’s economy. However, it is under significant threat from insect pests that damage crops both pre- and post-harvest. As a result, quarantine/biosecurity treatments in the form of fumigations form the vanguard of Australia’s defence against insect pests, both established and threatening to establish. The brown marmorated stink bug, an invasive pest yet to establish in Australia stands to cause enormous financial damage to multiple crops, an example being this thesis’ estimated cost over $300 million worth of damage to Australian wine grape production alone should poor biosecurity allow its establishment. Currently employed biosecurity treatments such as heat treatment, methyl bromide and sulfuryl fluoride are flawed when it comes to this pest. This has prompted evaluation of the organic and food-grade compound ethyl formate. Ethyl formate trials found that Probit 9 could be achieved in low temperatures against tolerant diapausing brown marmorated stink bug at 23.51 mg/L. It was then important to evaluate the potential of ethyl formate to protect one of Australia’s most valuable agricultural exports, grain. Currently the export grains value chain relies on phosphine to meet federally mandate nil-tolerance for live insects, but this future of this fumigant is threatened by resistance development. The simulated grain silo bioassay found that grain sorption of the fumigant did not prevent ethyl formate from effectively controlling adult stored grain insect pests. Finally, it was important to evaluate the potential inter-reaction between ethyl formate and representative materials / products encountered in biosecurity treatments. Results from this evaluation found no deleterious effects on the integrity and function of various plastics and metals. In conclusion, ethyl formate was shown to be a safe, reliable and effective fumigant with a range of applications, and needs to be considered as potential mainstay biosecurity treatment for both import and exports
Identification of key gene networks and deciphering transcriptional regulators associated with peanut embryo abortion mediated by calcium deficiency
Get PDFPeanut embryo development is easily affected by a variety of nutrient elements in the soil, especially the calcium level. Peanut produces abortive embryos in calcium-deficient soil, but underlying mechanism remains unclear. Thus, identifying key transcriptional regulators and their associated regulatory networks promises to contribute to a better understanding of this process. In this study, cellular biology and gene expression analyses were performed to investigate peanut embryo development with the aim to discern the global architecture of gene regulatory networks underlying peanut embryo abortion under calcium deficiency conditions. The endomembrane systems tended to disintegrate, impairing cell growth and starch, protein and lipid body accumulation, resulting in aborted seeds. RNA-seq analysis showed that the gene expression profile in peanut embryos was significantly changed under calcium deficiency. Further analysis indicated that multiple signal pathways were involved in the peanut embryo abortion. Differential expressed genes (DEGs) related to cytoplasmic free Ca2+ were significantly altered. DEGs in plant hormone signaling pathways tended to be associated with increased IAA and ethylene but with decreased ABA, gibberellin, cytokinin, and brassinosteroid levels. Certain vital genes, including apoptosis-inducing factor, WRKYs and ethylene-responsive transcription factors, were up-regulated, while key regulators of embryo development, such as TCP4, WRI1, FUS3, ABI3, and GLK1 were down-regulated. Weighted gene co-expression network analysis (WGCNA) identified 16 significant modules associated with the plant hormone signaling, MAPK signaling, ubiquitin mediated proteolysis, reserve substance biosynthesis and metabolism pathways to decipher regulatory network. The most significant module was darkolivegreen2 and FUS3 (AH06G23930) had the highest connectivity among this module. Importantly, key transcription factors involved in embryogenesis or ovule development including TCP4, GLK1, ABI3, bHLH115, MYC2, etc., were also present in this module and down regulated under calcium deficiency. This study presents the first global view of the gene regulatory network involved in peanut embryo abortion under calcium deficiency conditions and lays foundation for improving peanut tolerances to calcium deficiency by a targeted manipulation of molecular breeding
Historical and scientific evidence for the origin and cultural importance to Australia’s first-nations peoples of the laboratory accession of Nicotiana benthamiana, a model for plant virology
Get PDFNicotiana benthamiana is an indigenous plant species distributed across northern Australia. The laboratory accession (LAB) of N. benthamiana has become widely adopted as a model host for plant viruses, and it is distinct from other accessions morphologically, physiologically, and by having an attenuation-of-function mutation in the RNA-dependent RNA polymerase 1 (NbRdr1) gene, referred to as NbRdr1m. Recent historical evidence suggested LAB was derived from a 1936 collection by John Cleland at The Granites of the Northern Territory, although no scientific evidence was provided. We provide scientific evidence and further historical evidence supporting the origin of LAB as The Granites. Analysis of a herbarium specimen of N. benthamiana collected by Cleland in 1936 revealed that The Granites population contains plants heterozygous for the NbRdr1 locus, having both the functional NbRdr1 and the mutant NbRdr1m alleles. N. benthamiana was an important cultural asset actively utilised as the narcotic Pituri (chewing tobacco) by the Warlpiri Aboriginal people at the site, who prevented women of child-bearing age from consuming it. We propose that Aboriginal people selected some of the unique traits of LAB that have subsequently facilitated its adoption as a model plant, such as lack of seed dormancy, fast maturity, low nornicotine content, and gracility
Phenotypic and genotypic assessment of antimicrobial resistance in Escherichia coli from Australian cattle populations at Slaughter
No full textAustralia relies on periodic antimicrobial resistance (AMR) surveys to determine trends and changes in AMR in animal production systems. This study is a follow-up to a survey of Escherichia coli from healthy cattle at slaughter conducted in 2013, which provided baseline data on AMR prevalence across cattle groups and production practices. In this study, 591 beef cattle, 194 dairy cattle, and 216 veal calf fecal samples were collected from 25 beef and veal processing establishments in Australia, representing approximately 77% of total export volume. A total of 969 matrix-assisted laser desorption–ionization results confirmed commensal E. coli isolates from 574 beef cattle, 186 dairy cattle, and 209 veal calves were recovered, and antimicrobial susceptibility testing was carried out by microbroth dilution to 16 drugs from 10 classes interpreted against epidemiological cutoff breakpoints. Overall, a high proportion of E. coli isolates (83.8%) were wild type for all antimicrobials assessed. In addition, isolates that were non–wild type (NWT) for three or more classes of antimicrobial did not exceed 4% for any of the cattle groups. The prevalence of E. coli that were NWT for antimicrobials that are critical or of high importance to human health was very low, with 1.4% of all isolates tested determined to be NWT for fluoroquinolones, third-generation cephalosporins, or polymyxins. Genomic analysis of NWT isolates identified one beef cattle isolate (ST-10) harboring blaCMY-2 and a dairy isolate (ST-58) and two veal calf isolates (ST-58 and ST-394) that had qnrS1, which confer resistance to extended-spectrum cephalosporins and fluoroquinolones, respectively. The low levels of AMR reported in this study confirm previous Australian studies, which indicated that there is minimal evidence that specific production practices lead to widespread disproportionate development of NWT isolates