Entomopathogenic fungi and invasional meltdown

Invasive non-native (alien) species are considered to be one of the greatest threats to biodiversity (Millenium Ecosystem Assessment 2005) through predation, competition, hybridisation or as vectors of disease (Hulme et al., 2009). The movement of peole and goods is increasing the rate of invasive alien species arriving in countries around the globe. A recent inventory of alien species in Europe revealed a figure of 11000 species (Hulme et al., 2009) but it is recognised that this is a first approximation and likely to be an underestimate (Olenin & Didžiulis, 2009). The distinction between native species and alien species is problematic; species have been moving around the world over millennia and the origin of many species is uncertain. It is also evident that many archaeophytes and archaeozoans establish within native communities without detrimental effects on species and ecosystem processes (Pyšek et al., 2005). However, the small proportion of alien species that are problematic (invasive) are both ecologically and economically costly (Hulme et al., 2009). Furthermore, historically species movements have occurred within continents but in recent decades an increasing proportion of alien species are from other continents (Hulme et al., 2009). Alien species originating from within a continent are predicted to be less invasive than those from other continents (Hulme et al., 2009)

Digital Stylometry: Linking Profiles Across Social Networks

There is an ever growing number of users with accounts on multiple social media and networking sites. Consequently, there is increasing interest in matching user accounts and profiles across different social networks in order to create aggregate profiles of users. In this paper, we present models for Digital Stylometry, which is a method for matching users through stylometry inspired techniques. We experimented with linguistic, temporal, and combined temporal-linguistic models for matching user accounts, using standard and novel techniques. Using publicly available data, our best model, a combined temporal-linguistic one, was able to correctly match the accounts of 31% of 5,612 distinct users across Twitter and Facebook.Comment: SocInfo'15, Beijing, China. In proceedings of the 7th International Conference on Social Informatics (SocInfo 2015). Beijing, Chin

Evaluasi Learning Management System pada Binus Online Learning menggunakan Metode USE

Pembelajaran online semakin populer di Indonesia di tengah  pandemi Covid-19 yang mengharuskan masyarakat untuk melakukan  social distancing. Salah satu sumber belajar yang banyak dimanfaatkan pada masa ini adalah learning management system berbasis web. Tingkat pemanfaatan learning management system berbasis web dipengaruhi oleh antarmuka pengguna. Penelitian ini bertujuan untuk mengevaluasi usabiltity antarmuka Learning Management System Binus Online Learning. 87 peserta direkrut dalam percobaan usability testing. Peserta diminta untuk mengisi kuisioner USE yang berkaitan dengan penggunaan fitur learning management system. Kuesioner USE diproses menggunakan metode deskriptif statistik. Aspek Usefulness, Ease of Use, Ease of Learn, and Satisfaction. Tingkat usability Learning Management System Binus Online Learning memperoleh persentase lebih dari 81,8% sehingga bisa dianggap sangat layak. Hasil keseluruhan kelayakan mengkategorikan Learning Management System Binus Online Learning sebagai Sangat Layak

Properties and stabilization of an extracellular α-glucosidase from the extremely thermophilic archaebacteria Thermococcus strain AN 1: enzyme activity at 130°C

An extracellular α-glucosidase from the thermophilic archaebacterium Thermococcus strain AN1 was purified 875-fold in five steps (Hiload Q-Sepharose, phenyl Sepharose, HPHT-hydroxyapatite, gel filtration and Mono Q chromatography) with a yield of 4%. It is a monomer with a molecular mass of about 60 kDa and a pI around 5. At 98°C, the purified enzyme in buffer has a half-life around 35 min, which is increased to around 215 min in presence of l% (w/v) dithiothreitol and 1% (w/v) BSA. Dithiothreitol (1%, w/v) and BSA (0.4%, w/v) also substantially increase the enzyme activity. The Km at 75°C is 0.41 mM with pNP-α- -glucopyranoside as substrate. The substrate preference of the enzyme is: pNP-α-D-glucoside > nigerose > panose > palatinose > isomaltose > maltose and turanose. No activity was found against starch, pullulan, amylose, maltotriose, maltotetraose, isomaltotriose, cellobiose and β-gentiobiose. A variety of techniques including immobilization (e.g., on epoxy and glass beads), chemical modification (cross- and cocross-linking) and the use of additives (including polyhydroxylic molecules, BSA, salts, etc.) were applied to enhance stability at temperatures above 100°C. The half-life could be increased from about 4 min at 110°C to 30–60 min at 130°C in presence of 90% (w/v) sorbitol, 1% (w/v) dithiothreitol and l% (w/v) BSA, and by cocross-linking with BSA in the presence of 90% (w/v) sorbitol. The stabilized enzyme showed good activity at 130°C

Symbiotic outcome modified by the diversification from 7 to over 700 nodule specific cysteine rich peptides

Legume-rhizobium symbiosis represents one of the most successfully co-evolved mutualisms. Within nodules, the bacterial cells undergo distinct metabolic and morphological changes and differentiate into nitrogen-fixing bacteroids. Legumes in the inverted repeat lacking clade (IRLC) employ an array of defensin-like small secreted peptides (SSPs), known as nodule-specific cysteine-rich (NCR) peptides, to regulate bacteroid differentiation and activity. While most NCRs exhibit bactericidal effects in vitro, studies confirm that inside nodules they target the bacterial cell cycle and other cellular pathways to control and extend rhizobial differentiation into an irreversible (or terminal) state where the host gains control over bacteroids. While NCRs are well established as positive regulators of effective symbiosis, more recent findings also suggest that NCRs affect partner compatibility. The extent of bacterial differentiation has been linked to species-specific size and complexity of the NCR gene family that varies even among closely related species, suggesting a more recent origin of NCRs followed by rapid expansion in certain species. NCRs have diversified functionally, as well as in their expression patterns and responsiveness, likely driving further functional specialisation. In this review, we evaluate the functions of NCR peptides and their role as a driving force underlying the outcome of rhizobial symbiosis, where the plant is able to determine the outcome of rhizobial interaction in a temporal and spatial manner

Pathogen avoidance by insect predators

Insects can detect cues related to the risk of attack by their natural enemies. Pathogens are among the natural enemies of insects and entomopathogenic fungi attack a wide array of host species. Evidence documents that social insects in particular have adapted behavioural mechanisms to avoid infection by fungal pathogens. These mechanisms are referred to as 'behavioural resistance'. However, there is little evidence for similar adaptations in non-social insects. We have conducted experiments to assess the potential of common insect predators to detect and avoid their entomopathogenic fungal natural enemy Beauveria bassiana. The predatory bug Anthocoris nemorum was able to detect and avoid nettle leaves that were treated with B. bassiana. Females laid fewer eggs on leaf halves contaminated with the pathogen. Similarly, females were very reluctant to contact nettle leaves contaminated with the fungus compared to uncontaminated control leaves in ‘no-choice’ experiments. Adult seven spot ladybirds, Coccinella septempunctata, overwinter in the litter layer often in groups. Adult C. septempunctata modified their overwintering behaviour in relation to the presence of B. bassiana conidia in soil and sporulating conspecifics by moving away from sources of infection. Furthermore active (non-overwintering) adult C. septempunctata were also able to detect and avoid B. bassiana conidia on different substrates; bean leaves, soil and sporulating on dead conspecifics. Our studies show that insect predators have evolved mechanisms to detect and avoid pathogens that they are susceptible to. Fungal pathogens may be significant mortality factors among populations of insect predators, especially long-lived species that must diapause before reproduction. Likewise, actively foraging species are more likely to come in contact with pathogens than predators that sit and wait for prey. These particular groups of insects will benefit from adaptations to avoid pathogens

Arginase from kiwifruit: properties and seasonal variation

The in vitro activity of arginase (EC 3.5.3.1) was investigated in youngest-mature leaves and roots (1-3 mm diameter) of kiwifruit vines (Actinidia deliciosa var. deliciosa) during an annual growth cycle, and enzyme from root material partially purified. No seasonal trend in the specific activity of arginase was observed in roots. Measurements in leaves, however, rose gradually during early growth and plateaued c. 17 weeks after budbreak. Changes in arginase activity were not correlated with changes in the concentration of arginine (substrate) or glutamine (likely end-product of arginine catabolism) in either tissue during the growth cycle. Purification was by (NH4)2SO4 precipitation and DEAE-cellulose chromatography. The kinetic properties of the enzyme, purified 60-fold over that in crude extracts, indicated a pH optimum of 8.8, and a Km (L-arginine) of 7.85 mM. Partially-purified enzyme was deactivated by dialysis against EDTA, and reactivated in the presence of Mn²⁺, Co²⁺, and Ni²⁺

Heavy social drinkers score higher on implicit wanting and liking for alcohol than alcohol-dependent patients and light social drinkers

Abstract Background and objectives Automatic hedonic ("liking") and incentive ("wanting") processes are assumed to play an important role in addiction. Whereas some neurobiological theories suggest that these processes become dissociated when drug use develops into an addiction (i.e. "liking" becomes weaker, whereas "wanting" becomes exaggerated; e.g. Robinson & Berridge, 1993), other theories suggest that there is a linear relationship between these two processes (i.e. both "liking" and "wanting" increase equally; e.g. Koob & Le Moal, 1997). Our aim was to examine "wanting" and "liking" in three groups of participants: alcohol-dependent patients, heavy social drinkers, and light social drinkers. Methods Participants performed two different single target implicit association tests (ST-IATs; e.g. Bluemke & Friese, 2007) and explicit ratings that were designed to measure "liking" and "wanting" for alcohol. Results Our results are in sharp contrast with the theories of both Robinson and Berridge and Koob and Le Moal: heavy drinkers had higher scores than light drinkers and alcohol-dependent patients on both the wanting ST-IAT and the liking ST-IAT. There were no differences between alcohol-dependent patients and light drinkers. Explicit ratings mirrored these results. Limitations These findings suggest that our ST-IATs are not valid measures of "wanting" and "liking". Instead, they might assess more complex knowledge regarding participants' experiences and goals. Conclusions These findings suggest that the relationship between drug consumption and appetitive drug associations is not linear, highlighting the importance of testing both sub-clinical and clinical samples in future research.SCOPUS: ar.jinfo:eu-repo/semantics/publishe