Bemisia tabaci has long been considered a complex species. It rose to global prominence in the 1980s owing to the global invasion by the commonly named B biotype. Since then, the concomitant eruption ...of a group of plant viruses known as begomoviruses has created considerable management problems in many countries. However, an enduring set of questions remains: Is B. tabaci a complex species or a species complex, what are Bemisia biotypes, and how did all the genetic variability arise? This review considers these issues and concludes that there is now sufficient evidence to state that B. tabaci is not made up of biotypes and that the use of biotype in this context is erroneous and misleading. Instead, B. tabaci is a complex of 11 well-defined high-level groups containing at least 24 morphologically indistinguishable species.
Magnesium (Mg) alloys, as the lightest metal engineering materials, have broad application prospects. However, the strength and ductility of traditional Mg alloys are still relativity low and ...difficult to improve simultaneously. Refining grain size via the deformation process based on the grain boundary strengthening and the transition of deformation mechanisms is one of the feasible strategies to prepare Mg alloys with high strength and high ductility. In this review, the effects of grain size on the strength and ductility of Mg alloys are summarized, and fine-grained Mg alloys with high strength and high ductility developed by various severe plastic deformation technologies and improved traditional deformation technologies are introduced. Although some achievements have been made, the effects of grain size on various Mg alloys are rarely discussed systematically and some key mechanisms are unclear or lack direct microscopic evidence. This review can be used as a reference for further development of high-performance fine-grained Mg alloys.
Research on students' understanding of the greenhouse effect and global warming has been focused on identifying and overcoming misconceptions. However, to date, very few studies have looked into the ...ways in which student conceptions are organised and interrelated from a model-based perspective. In this study, we investigated student-generated drawings (N = 130) of the greenhouse effect from two universities in Taiwan. The goals were to explore student mental models, which underlie and organise their visual representations, and further examine whether and how these mental models are associated with other important climate-related knowledge. For our purposes, computer-based grouping was used instead of the common practice of human expert-based inspection. Four mental models emerged in the process of factor analysing salient characteristics of student drawings, and showed some commonalities and differences compared with previous findings. Further correlation analysis revealed significant, positive relationships between the Textbook-like model and climate system knowledge, and between the Sources (of greenhouse gases) model and climate action knowledge. These results provided some fresh insight into existing knowledge about student mental models of the greenhouse effect. The relationships of students' conceptualisation of the greenhouse effect and global warming can serve as a basis for instructional considerations in climate change education.
The interactions of vector–virus–plant have important ecological and evolutionary implications. While the tripartite interactions have received some attention, little is known about whether vector ...infestation affects subsequent viral transmission and infection.
Working with the whitefly Bemisia tabaci, begomovirus and tobacco/tomato, we demonstrate that pre-infestation of plants by the whitefly vector reduced subsequent plant susceptibility to viral transmission. Pre-infestation by the cotton bollworm, a nonvector of the virus, likewise repressed subsequent viral transmission.
The two types of insects, with piercing and chewing mouthparts, respectively, activated different plant signaling pathways in the interactions. Whitefly pre-infestation activated the salicylic acid (SA) signaling pathway, leading to deposition of callose that inhibited begomovirus replication/movement. Although cotton bollworm infestation elicited the jasmonic acid (JA) defense pathway and was beneficial to virus replication, the pre-infested plants repelled whiteflies from feeding and so decreased virus transmission. Experiments using a pharmaceutical approach with plant hormones or a genetic approach using hormone transgenic or mutant plants further showed that SA played a negative but JA played a positive role in begomovirus infection.
These novel findings indicate that both vector and nonvector insect feeding of a plant may have substantial negative consequences for ensuing viral transmission and infection.
The Fokas–Lenells equations: Bilinear approach Liu, Shu‐zhi; Wang, Jing; Zhang, Da‐jun
Studies in applied mathematics (Cambridge),
February 2022, 2022-02-00, 20220201, Letnik:
148, Številka:
2
Journal Article
Recenzirano
Odprti dostop
In this paper, the Fokas–Lenells (FL) equations are investigated via bilinear approach. We bilinearize the unreduced FL system, derive double Wronskian solutions, and then, by means of a reduction ...technique we obtain variety of solutions of the reduced equations. This enables us to have a full profile of solutions of the classical and nonlocal FL equations. Some obtained solutions are illustrated based on asymptotic analysis. As a notable new result, we obtain solutions to the FL equation, which are related to real discrete eigenvalues and not reported before in the analytic approaches. These solutions behave like (multi)periodic waves or solitary waves with algebraic decay. In addition, we also obtain solutions to the two‐dimensional massive Thirring model from those of the FL equation.
Huangqi Chifeng Tang (HQCFT), a traditional Chinese formula of three herbs, has been used to treat cerebral infarction (CI). Saposhnikoviae Radix (SR) was designed as a guiding drug for HQCFT to ...improve its angiogenic and anti-inflammatory effects. In this study, TTC staining was used to detect the area of CI. H&E staining was used to detect the histopathologic changes in the cerebral tissue. Western blotting was performed to detect the protein expression of NLRP3, caspase 1, IL-1β, IL-6, TNF-α, MMP-9, VEGF, and VEGFR2 in cerebral tissue. Immunohistochemistry was used to detect the protein expression of MMP-9, VEGF, and VEGFR2. The contents of HIF-1α, NLRP3, caspase 1, IL-1β, IL-6, and TNF-α in the serum were determined by ELISA. Our study showed that HQCFT and HQCFT-SR could improve the pathological condition and reduce the infarcted area of the brain tissue in a rat model. In addition, HQCFT and HQCFT-SR significantly decreased the expression levels and serum contents of NLRP3, caspase 1, IL-1β, IL-6, and TNF-α; increased the expression levels of the VEGF and VEGFR2 proteins; and obviously reduced the serum content of HIF-1α. Importantly, the cytokines in brain tissue and serum from the HQCFT group exhibited better efficacy than those from the HQCFT-SR group. HQCFT exerted significant angiogenic and anti-inflammatory effects in rats subjected to middle cerebral artery occlusion (MCAO); these effects can be attributed to the guiding and enhancing effect of SR.
Previous phylogenetic analyses of species within the genus Golovinomyces (Ascomycota, Erysiphales), based on ITS and 28S rDNA sequence data, revealed a co-evolutionary relationship between powdery ...mildew species and hosts of certain tribes of the plant family Asteraceae. Golovinomyces growing on host plants belonging to the Heliantheae formed a single lineage, comprised of a morphologically differentiated complex of species, which included G. ambrosiae, G. circumfusus, and G. spadiceus. However, the lineage also encompassed sequences retrieved from Golovinomyces specimens on other Asteraceae tribes as well as other plant families, suggesting the involvement of a plurivorous species. A multilocus phylogenetic examination of this complex, using ITS, 28S, IGS (intergenic spacer), TUB2 (beta-tubulin), and CHS1 (chitin synthase I) sequence data was carried out to clarify the discrepancies between ITS and 28S rDNA sequence data and morphological differences. Furthermore, the circumscription of species and their host ranges were emended.
The phylogenetic and morphological analyses conducted in this study revealed three distinct species named, viz., (1) G. ambrosiae emend. (including G. spadiceus), a plurivorous species that occurs on a multitude of hosts including, Ambrosia spp., multiple species of the Heliantheae and plant species of other tribes of Asteraceae including the Asian species of Eupatorium; (2) G. latisporus comb. nov. (≡ Oidium latisporum), the closely related, but morphologically distinct species confined to hosts of the Heliantheae genera Helianthus, Zinnia, and most likely Rudbeckia; and (3) G. circumfusus confined to Eupatorium cannabinum in Europe.
The present results provide strong evidence that the combination of multi-locus phylogeny and morphological analysis is an effective way to identify species in the genus Golovinomyces.
Viral encephalitis is an inflammatory disease of the brain parenchyma and caused by various viral infections. In vivo monitoring of the progression of viral infections can aid accurate diagnosis of ...viral encephalitis and effective intervention. We developed an activatable and reversible virus‐mimicking near‐infrared II nanoprobe consisting of an Fe2+‐coordinated, viral protein‐decorated vesicle encapsulating PbS quantum dots with a 1300 nm fluorescence emission. The probe can cross the blood–brain barrier and monitor real‐time changes in reactive oxygen and nitrogen species concentrations during viral infection by tuning the quenching level of quantum dots and regulating the fusion–fission behavior of vesicles via changes in Fe oxidation state. This switching strategy reduces background noise and improves detection sensitivity, making this nanoprobe a promising imaging agent for dynamic visualization of viral encephalitis and future clinical applications.
We present an activatable virus‐mimicking NIR‐II nanoprobe based on PbS quantum dots (QDs) encapsulated in a Fe2+‐coordinating viral protein‐decorated vesicle. The probe can cross the blood–brain barrier and monitor real‐time changes in reactive oxygen and nitrogen species concentrations during viral infection, providing a favorable approach for dynamic visualization of viral encephalitis.
There have been a large number of reports about glial cell dysfunction being related to major psychiatric diseases such as schizophrenia (SCZ), bipolar disorder (BD), and major depressive disorder ...(MDD). In this review, we provide an overview of postmortem studies analyzing the structural changes of glial cells in these three major psychiatric diseases, including the density, number and size of glial cells, and the expression of related markers. Up to May 1, 2021, 108 articles that met the inclusion criteria were identified by searching PubMed and Web of Science. Although most studies evaluating total glial cells did not show abnormalities in the brains of postmortem patients, astrocytes, microglial cells, and oligodendrocytes seem to have specific patterns of changes in each disease. For example, out of 20 studies that evaluated astrocyte markers in MDD, 11 studies found decreased astrocyte marker expression in MDD patients. Similarly, out of 25 studies evaluating oligodendrocyte markers in SCZ, 15 studies showed decreased expression of oligodendrocyte markers in different brain regions of SCZ patients. In addition, activated microglial cells were observed in patients with SCZ, BD, and MDD, but suicide may be a confounding factor for the observed effects. Although the data from the included studies were heterogeneous and this cannot be fully explained at present, it is likely that there are a variety of contributing factors, including the measured brain regions, methods of measurement, gender, age at time of death, and medications.
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