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Inside the belly of the beast : exploring the gut bacterial diversity of Gonipterus sp. n. 2
Knoppersen, Rosa Sophie; Bose, Tanay; Coutinho, Teresa A.; Hammerbacher, Almuth (Springer, 2025-04-12)
The Eucalyptus snout beetle (Gonipterus sp. n. 2) is a destructive invasive pest of Eucalyptus plantations, responsible for significant defoliation and wood yield losses globally. Native to Australia, this beetle has adapted to thrive on diverse Eucalyptus hosts, overcoming their chemical defences. However, the mechanisms by which Gonipterus tolerates or utilises these plant defence metabolites remain poorly understood. In South Africa, Gonipterus sp. n. 2 poses a significant threat to Eucalyptus plantations by causing extensive defoliation and leading to substantial reductions in growth and wood production. This study investigates the relationship between diet, host Eucalyptus species, and the gut microbiome of Gonipterus sp. n. 2. Using controlled feeding experiments, beetles were reared on artificial, semi-artificial, and natural diets, as well as two Eucalyptus genotypes with distinct secondary metabolite profiles. High-throughput 16S rDNA sequencing and gas chromatography-mass spectrometry (GC–MS) revealed significant shifts in gut bacterial diversity and composition across diets. Natural diets supported the most diverse microbial communities, while artificial diets fostered a homogenised microbiome dominated by opportunistic taxa like Serratia. Host-specific effects were observed in frass microbiota, with substantial biotransformation of monoterpenes into less toxic derivatives. The results highlight the plasticity of Gonipterus gut microbiota, which enables metabolic adaptability and resilience in diverse environments. This microbial flexibility underpins the invasiveness of Gonipterus, emphasising the role of gut symbionts in overcoming host chemical defences. Understanding these interactions offers novel insights for microbiome-targeted pest management strategies, providing a sustainable approach to mitigate the impact of Gonipterus on global Eucalyptus forestry.
Production of in situ mixed gas phase volatile organic compound standards for sorbent tube applications
Leakwe, Ntoko Moses; Welthagen, Werner; Forbes, Patricia B.C. (Elsevier, 2025-12)
Volatile organic compounds (VOCs) are a significant class of air pollutants, as they pose a risk to human health and the environment. Precise quantification of VOCs sampled onto sorbent tubes requires gas phase standards at suitable concentrations. Herein, we present a: - gas standard preparation method for benzene, toluene, ethylbenzene and xylene (BTEX) prepared from liquid standards by means of evaporation and dynamic dilution with nitrogen- demonstration of the applicability of the LiqMix Cascade gas mix system. Repeatability and reproducibility were first successfully demonstrated via direct GC–MS analysis of generated gas mixtures. Then µg levels of generated gas standards were adsorbed onto sorbent tubes employed in active sampling and ng levels were collected onto Radiello cartridges used in passive sampling, followed by liquid extraction or thermal desorption and GC–MS analysis. Accuracy was verified by a BTEX certified reference material (99 % recovery). The LiqMix Cascade gas mix system was shown to produce precise and repeatable concentrations of BTEX gas phase standards for sorbent tube sampling applications for the first time.
Effect of malting on endosperm texture of Type 1 non-tannin sorghum grains and functional properties of the malted flour
Mbock, Emilie Danielle; Duodu, Kwaku Gyebi; Emmambux, Mohammad Naushad (Elsevier, 2025-11)
The effect of malting on endosperm texture and functional properties of the malted flour of two Type I sorghums (red and white phenotypes) was studied. Malting modified the endosperm of the two sorghums with a partial change from corneous to floury type, possibly due to the increased activity of α-amylase. The sprouted red sorghum grains appeared to have a higher proportion of floury endosperm than white sorghum grains. This could be attributed to the increased synthesis and activity of hydrolytic enzymes, such as α-amylase, which break down starch to provide energy for the germinating embryo, ultimately boosting the germinative energy of red sorghum. The α-amylase activity triggered during malting increased the sugar content and decreased the viscosity of starch during the pasting of the malted flour, suggesting starch depolymerisation. The degradation of starch decreased their ability to absorb water (water absorption index) and increased water-soluble compounds (water solubility index) in the medium. The action of protease enzymes in digesting some of the protein bodies and matrix surrounding the starch could also increase the accessibility of the starch to amylase enzymes. Malting is a promising green, traditional food processing technique to enhance the end-use quality of sorghum during processing.
Capture-recapture estimates of Antarctic blue whale abundance and population growth rate
Olson, Paula A.; Kinzey, Douglas; Double, Michael C.; Matsuoka, Koji; Findlay, Kenneth Pierce (Wiley, 2025-07)
Photo-identifications of Antarctic blue whales (Balaenoptera musculus intermedia) collected from 2003/2004 to 2018/2019 were used in a capture–recapture analysis to estimate abundance and population growth rate for the circumpolar Antarctic. Two capture–recapture models, POPAN and Pradel, were applied to these data. Estimates of annual abundance and their variances from the left and right side photo data were inferred using multimodel averaging, weighted by corrected Akaike information criterion (AICc), of 26 model configurations with prespecified survival rates from .75 to 1.0. These estimates based on the left and right side databases were then combined using inverse-variance averaging into single estimates for each year. The POPAN superpopulation estimate (total number of individuals present during the sampling period) was 3,506 whales, 95% confidence interval (CI) [2,107, 5,832]. The estimated abundance from the final year of the study in 2018/2019 was 1,817 whales, 95% CI [714, 4,624]. The abundance estimates in this study may be biased downwards due to capture heterogeneity as a result of unequal spatial sampling. Population growth rate estimates were 11% from Pradel and 10% from POPAN. These rates were within the confidence interval estimated by a previous study for Antarctic blue whale population growth rate.
Potential vocalizations of Bryde's whales in False Bay, South Africa
Faustmann, Alexander; Shabangu, Fannie Welcome; Versfeld, Jaco D. J. J. (Wiley, 2025-07)
Bryde's whales are one of the lesser-known species of baleen whales that inhabit tropical and subtropical waters across the globe (Kato & Perrin, 2018). Individuals from both subspecies, Balaenoptera edeni edeni (Anderson, 1878) and B. e. brydei (Olsen, 1913), also referred to as the offshore and inshore forms (Best, 1977; Best, 2001), respectively, can be found inhabiting the waters off the South African coast (Constantine et al., 2018; Penry et al., 2016). The two subspecies designations had originally been synonymized (Junge, 1950) but were later recognized as distinct, as suggested by Rice (1998), and recently confirmed genetically (Penry et al., 2018). Bryde's whales are often misidentified as other species, and their taxonomy has yet to be well resolved (Smultea et al., 2010). Further studies of the phylogenetic relationships between geographically isolated populations of Bryde's whales, by means of differences in behavior, vocalization, and mitochondrial DNA, are required to avoid conservation risks to genetically distinct populations, such as those now faced by Rice's whale (Constantine et al., 2018; Penry et al., 2018). Aside from the issues regarding taxonomy and population abundance of isolated stocks, relatively little is known regarding the swimming behavior, migratory habits, vocalizations, and the current population trend of Bryde's whales (Constantine et al., 2018; Helble et al., 2024; Penry et al., 2016).