Low genetic variation of invasive Fallopia spp. in their northernmost European distribution range

Knowledge about the reproduction strategies of invasive species is fundamental for effective control. The invasive Fallopia taxa (Japanese knotweed s.l.) reproduce mainly clonally in Europe, and preventing spread of vegetative fragments is the most important control measure. However, high levels of genetic variation within the hybrid F. × bohemica indicate that hybridization and seed dispersal could be important. In Norway in northern Europe, it is assumed that these taxa do not reproduce sexually due to low temperatures in the autumn when the plants are flowering. The main objective of this study was to examine the genetic variation of invasive Fallopia taxa in selected areas in Norway in order to evaluate whether the taxa may reproduce by seeds in their most northerly distribution range in Europe. Fallopia stands from different localities in Norway were analyzed with respect to prevalence of taxa, and genetic variation within and between taxa was studied using amplified fragment length polymorphism (AFLP). Taxonomic identification based on morphology corresponded with identification based on simple sequence repeats (SSR) and DNA ploidy levels (8× F. japonica, 6× F. × bohemica and 4× F. sachalinensis). No genetic variation within F. japonica was detected. All F. × bohemica samples belonged to a single AFLP genotype, but one sample had a different SSR genotype. Two SSR genotypes of F. sachalinensis were also detected. Extremely low genetic variation within the invasive Fallopia taxa indicates that these taxa do not reproduce sexually in the region, suggesting that control efforts can be focused on preventing clonal spread. Climate warming may increase sexual reproduction of invasive Fallopia taxa in northern regions. The hermaphrodite F. × bohemica is a potential pollen source for the male‐sterile parental species. Targeted eradication of the hybrid can therefore reduce the risk of increased sexual reproduction under future warmer climate.     

Cationic surfactant mediated fibrillogenesis in bovine liver catalase: a biophysical approach

Protein aggregation into oligomers and mature fibrils are associated with more than 20 diseases in humans. The interactions between cationic surfactants dodecyltrimethylammonium bromide (DTAB) and tetradecyltrimethylammonium bromide (TTAB) with varying alkyl chain lengths and bovine liver catalase (BLC) were examined by various biophysical approaches. The delicate coordination of electrostatic and hydrophobic interactions with protein, play imperative role in aggregation. In this article, we have reconnoitered the relation between charge, hydrophobicity and cationic surfactants DTAB and TTAB on BLC at pH 7.4 and 9.4 which are two and four units above pI, respectively. We have used techniques like turbidity, Rayleigh light scattering, far-UV CD, ThT, ANS, Congo red binding assay, DLS, and transmission electron microscopy. The low concentration ranges of DTAB (0–600 μM) and TTAB (0–250 μM) were observed to increase aggregation at pH 9.4. Nevertheless, at pH 7.4 only TTAB was capable of inducing aggregate. DTAB did not produce any significant change in secondary structure at pH 7.4 suggestive of the role of respective charges on surfactants and protein according to the pI and alkyl chain length. The morphology of aggregates was further determined by TEM, which proved the existence of a fibrillar structure. The surfactants interaction with BLC was primarily electrostatic as examined by ITC. Our work demystifies the critical role of charge as well as hydrophobicity in amyloid formation.     

Severe hepatic fibrosis in Schistosoma mansoni infection is controlled by a major locus that is closely linked to the interferon-gamma receptor gene.

Lethal disease due to hepatic periportal fibrosis occurs in 2%-10% of subjects infected by Schistosoma mansoni in endemic regions such as Sudan. It is unknown why few infected individuals present with severe disease, and inherited factors may play a role in fibrosis development. Schistosoma mansoni infection levels have been shown to be controlled by a locus that maps to chromosome 5q31-q33. To investigate the genetic control of severe hepatic fibrosis (assessed by ultrasound examination) causing portal hypertension, a segregation analysis was performed in 65 Sudanese pedigrees from the same village. Results provide evidence for a codominant major gene, with.16 as the estimated allele A frequency predisposing to advanced periportal fibrosis. For AA males, AA females, and Aa males a 50% penetrance is reached after, respectively, 9, 14, and 19 years of residency in the area, whereas for other subjects the penetrance remains <.02 after 20 years of exposure. Linkage analysis performed in four candidate regions shows that this major locus maps to chromosome 6q22-q23 and that it is closely linked (multipoint LOD score 3.12) to the IFN-gammaR1 gene encoding the receptor of the strongly antifibrogenic cytokine interferon-gamma. These results show that infection levels and advanced hepatic fibrosis in human schistosomiasis are controlled by distinct loci; they suggest that polymorphisms within the IFN-gammaR1 gene could determine severe hepatic disease due to S. mansoni infection and that the IFN-gammaR1 gene is a strong candidate for the control of abnormal fibrosis observed in other diseases.     

Extended Fujita approach to the molecular weight distribution of polysaccharides and other polymeric systems

In 1962 H. Fujita (H. Fujita, Mathematical Theory of Sedimentation Analysis, Academic Press, New York, 1962) examined the possibility of transforming a quasi-continuous distribution g(s) of sedimentation coefficient s into a distribution f(M) of molecular weight M for linear polymers using the relation f(M)=g(s)·(ds/dM) and showed that this could be done if information about the relation between s and M is available from other sources. Fujita provided the transformation based on the scaling relation s=κ(s)M(0.5), where κ(s) is taken as a constant for that particular polymer and the exponent 0.5 essentially corresponds to a randomly coiled polymer under ideal conditions. This method has been successfully applied to mucus glycoproteins (S.E. Harding, Adv. Carbohyd. Chem. Biochem. 47 (1989) 345-381). We now describe an extension of the method to general conformation types via the scaling relation s=κM(b), where b=0.4-0.5 for a coil, ～0.15-0.2 for a rod and ～0.67 for a sphere. We give examples of distributions f(M) versus M obtained for polysaccharides from SEDFIT derived least squares g(s) versus s profiles (P. Schuck, Biophys. J. 78 (2000) 1606-1619) and the analytical derivative for ds/dM performed with Microcal ORIGIN. We also describe a more direct route from a direct numerical solution of the integral equation describing the molecular weight distribution problem. Both routes give identical distributions although the latter offers the advantage of being incorporated completely within SEDFIT. The method currently assumes that solutions behave ideally: sedimentation velocity has the major advantage over sedimentation equilibrium in that concentrations less than 0.2mg/ml can be employed, and for many systems non-ideality effects can be reasonably ignored. For large, non-globular polymer systems, diffusive contributions are also likely to be small.     

The Helsinki Rat Microsurgical Sidewall Aneurysm Model

Experimental saccular aneurysm models are necessary for testing novel surgical and endovascular treatment options and devices before they are introduced into clinical practice. Furthermore, experimental models are needed to elucidate the complex aneurysm biology leading to rupture of saccular aneurysms.Several different kinds of experimental models for saccular aneurysms have been established in different species. Many of them, however, require special skills, expensive equipment, or special environments, which limits their widespread use. A simple, robust, and inexpensive experimental model is needed as a standardized tool that can be used in a standardized manner in various institutions.The microsurgical rat abdominal aortic sidewall aneurysm model combines the possibility to study both novel endovascular treatment strategies and the molecular basis of aneurysm biology in a standardized and inexpensive manner. Standardized grafts by means of shape, size, and geometry are harvested from a donor rat''s descending thoracic aorta and then transplanted to a syngenic recipient rat. The aneurysms are sutured end-to-side with continuous or interrupted 9-0 nylon sutures to the infrarenal abdominal aorta.We present step-by-step procedural instructions, information on necessary equipment, and discuss important anatomical and surgical details for successful microsurgical creation of an abdominal aortic sidewall aneurysm in the rat.     

Vitex agnus‐castus cannot be used as trap plant for the vector Hyalesthes obsoletus to prevent infections by ‘Candidatus Phytoplasma solani’ in northern Italian vineyards: Experimental evidence

Bois noir (BN), the most prevalent disease of the grapevine yellows complex, causes considerable yield loss in vineyards. BN is associated with phytoplasma strains of the species ‘Candidatus Phytoplasma solani’ (taxonomic subgroup 16SrXII‐A). In Europe, the BN phytoplasma is transmitted to grapevine mainly by Hyalesthes obsoletus, a polyphagous cixiid completing its life cycle on stinging nettle and field bindweed. As a result of the complexity of BN epidemiology, no effective control strategies have been developed. In previous studies conducted in the eastern Mediterranean coast of Israel, chaste tree (Vitex agnus‐castus) was found to be the preferred host plant of H. obsoletus but did not harbour BN phytoplasma. Thus, a ‘push and pull’ strategy was suggested based on the fact that chaste tree plants located at vineyard borders was an effective trap plant for H. obsoletus adults. However, in other studies carried out in the eastern Adriatic coast of Montenegro, chaste tree was found to be a key source plant for BN phytoplasma transmission to grapevine. This study aimed to investigate (i) the interaction between chaste tree and H. obsoletus through survival, attractiveness and oviposition experiments conducted comparing the behaviour of H. obsoletus in chaste tree versus stinging nettle and grapevine and (ii) the capability of chaste tree to harbor ‘Ca. P. solani’ in northern Italy through transmission trials. H. obsoletus adults were found to survive on chaste tree and grapevine over a 1 week period and prefer chaste tree to grapevine. Moreover, H. obsoletus produced eggs and overwintered as nymphs on chaste tree, even if at a lesser extent than on stinging nettle. H. obsoletus originating from nettle was found able to transmit ‘Ca. P. solani’ to chaste tree (2 plants of 16 were found infected by the BN phytoplasma strain St5 identified in H. obsoletus specimens). These results increased our knowledge about the role of Vitex agnus‐castus as host plant of H. obsoletus and BN phytoplasma in northern Italy and do not recommend considering chaste tree as trap plant at vineyard borders.     

Alleviation of cadmium stress by arbuscular mycorrhizal symbiosis

Abstract

Owing to the realization of the harmful effect of cadmium on the environment and plants and as the plants are sessile organisms, they need to increase the protective mechanisms to cope with Cd stress. Inoculation the plant with soil microbes at the place of their growing is an important strategy to support the plants against stresses. In this study, trigonella plants were inoculated with arbuscular mycorrhizal (AM) fungi under different CdCl₂ concentrations (0, 2.25, and 6.25?mM). AM inoculation increased growth parameters, chlorophyll, and protein contents. Root colonization was significantly increased at low Cd concentration (2.25?mM) and decreased at high one (6.25?mM). Also, with AM fungal inoculation, the translocation factor of trigonella plants significantly decreased as compared to non-AM ones at both low and high Cd concentrations. In addition, it was clearly that malondialdehyde content of trigonella plants increased significantly at both Cd concentrations and with AM fungal inoculation its content decreased compared to those of non-AM ones. AM inoculation significantly increased antioxidant enzymes activities compared to non-AM ones. Consequently, this study showed a tolerance strategy of AM trigonella plants against Cd stress, thus mycorrhizal symbiosis becomes a promising and suitable as phytostabilizers of Cd stressed soil.     

Of mitochondrion and COVID-19

COVID-19, a pandemic disease caused by a viral infection, is associated with a high mortality rate. Most of the signs and symptoms, e.g. cytokine storm, electrolytes imbalances, thromboembolism, etc., are related to mitochondrial dysfunction. Therefore, targeting mitochondrion will represent a more rational treatment of COVID-19. The current work outlines how COVID-19’s signs and symptoms are related to the mitochondrion. Proper understanding of the underlying causes might enhance the opportunity to treat COVID-19.     

An asymmetric and slightly dimerized structure for the tetanus toxoid protein used in glycoconjugate vaccines

Tetanus toxoid protein has been characterized with regard oligomeric state and hydrodynamic (low-resolution) shape, important parameters with regard its use in glycoconjugate vaccines. From sedimentation velocity and sedimentation equilibrium analysis in the analytical ultracentrifuge tetanus toxoid protein is shown to be mostly monomeric in solution (～86%) with approximately 14% dimer. The relative proportions do not appear to change significantly with concentration, suggesting the two components are not in reversible equilibrium. Hydrodynamic solution conformation studies based on high precision viscometry, combined with sedimentation data show the protein to be slightly extended conformation in solution with an aspect ratio ～3. The asymmetric structure presents a greater surface area for conjugation with polysaccharide than a more globular structure, underpinning its popular choice as a conjugation protein for glycoconjugate vaccines.