Теоретические основы интенсификации работы грануляционных устройств с усовершенствованной гидродинамикой

Одним із способів зменшення габаритів грануляційного обладнання є вдосконалення гідродинамічних умов перебування в ньому дисперсної фази. Цього можна досягти, зокрема, за рахунок застосування вихрових і високотурбулізованних потоків. Представлена робота присвячена обґрунтуванню можливості створення алгоритму управління рухом дисперсної фази в робочому просторі грануляційного пристрою, на підставі якого буде визначена його оптимальна конструкція з мінімальними габаритами.Одним из способов уменьшения габаритов грануляционного оборудования является усовершенствование гидродинамических условий пребывания в нём дисперсной фазы. Этого можно достичь, в частности, за счет применения вихревых и высокотурбулизованных потоков. Представленная работа посвящена обоснованию возможности создания алгоритма управления движением дисперсной фазы в рабочем пространстве грануляционного устройства, на основании которого будет определена его оптимальная конструкция с минимальными габаритами

Distribution of Bemisia tabaci in different agro-ecological regions in Uganda and the threat of vector-borne pandemics into new cassava growing areas

Previous studies in sub-Saharan Africa have showed the spread of cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) pandemics into different cassava growing regions by high Bemisia tabaci populations. Studies did indicate that there were stark differences in some whitefly species, yet they have not looked extensively across agroecologies. Members of B. tabaci species complex termed sub-Saharan Africa 1 (SSA1) and SSA2 have been linked to the spread of CMD and CBSD viruses. During the period of a severe CMD pandemic in the 1990s, SSA2 was the most predominant until the resurgence of SSA1, particularly SSA1-subgroup1 (SSA1-SG1) from the early 2000s to date. Cassava being a drought resilient crop has become an important food security crop and has been introduced into new areas and regions. Considering the role B. tabaci in the spread of cassava virus pandemics into neighboring regions, we investigated the genetic diversity and distribution of B. tabaci in nine different agro-ecological regions of Uganda in 2017. Adult whiteflies were collected from cassava and 33 other host plants from cassava-growing areas, those with limited cassava and areas with no cassava, where it is being introduced as a food security crop. The partial sequences of the mitochondrial cytochrome oxidase 1 (mtCO1) gene (657 bp) were used to determine the phylogenetic relationships between the sampled B. tabaci. Cassava B. tabaci SSA1 (-SG1, -SG2, -Hoslundia (previously called SSA1-SG1/2), -SG3), SSA2 and SSA3; non-cassava B. tabaci SSA6, SSA10, SSA11, SSA12, SSA13, MED-ASL, MED-Q1, MEAM1, Indian Ocean; and other Bemisia species, Bemisia afer and Bemisia Uganda1 were identified in the study. SSA3, one of the key B. tabaci species that occurs on cassava in West Africa, was identified for the first time in Uganda. The SSA1-SG1 was widely distributed, predominated on cassava and was found on 17 other host-plants. The ability of SSA1-SG1 to exist in environments with limited or no cassava growing poses the risk of continued spread of virus pandemics. Therefore, measures must be put in place to prevent the introduction of diseased materials into new areas, since the vectors exist

The molecular mechanisms that determine different degrees of polyphagy in the Bemisia tabaci species complex

The whitefly Bemisia tabaci is a closely related group of >35 cryptic species that feed on the phloem sap of a broad range of host plants. Species in the complex differ in their host‐range breadth, but the mechanisms involved remain poorly understood. We investigated, therefore, how six different B. tabaci species cope with the environmental unpredictability presented by a set of four common and novel host plants. Behavioral studies indicated large differences in performances on the four hosts and putative specialization of one of the species to cassava plants. Transcriptomic analyses revealed two main insights. First, a large set of genes involved in metabolism (>85%) showed differences in expression between the six species, and each species could be characterized by its own unique expression pattern of metabolic genes. However, within species, these genes were constitutively expressed, with a low level of environmental responsiveness (i.e., to host change). Second, within each species, sets of genes mainly associated with the super‐pathways “environmental information processing” and “organismal systems” responded to the host switching events. These included genes encoding for proteins involved in sugar homeostasis, signal transduction, membrane transport, and immune, endocrine, sensory and digestive responses. Our findings suggested that the six B. tabaci species can be divided into four performance/transcriptomic “Types” and that polyphagy can be achieved in multiple ways. However, polyphagy level is determined by the specific identity of the metabolic genes/pathways that are enriched and overexpressed in each species (the species' individual metabolic “tool kit”)

To B or Not to B: Comparative Genomics Suggests Arsenophonus as a Source of B Vitamins in Whiteflies

Insect lineages feeding on nutritionally restricted diets such as phloem sap, xylem sap, or blood, were able to diversify by acquiring bacterial species that complement lacking nutrients. These bacteria, considered obligate/primary endosymbionts, share a long evolutionary history with their hosts. In some cases, however, these endosymbionts are not able to fulfill all of their host's nutritional requirements, driving the acquisition of additional symbiotic species. Phloem-feeding members of the insect family Aleyrodidae (whiteflies) established an obligate relationship with Candidatus Portiera aleyrodidarum, which provides its hots with essential amino acids and carotenoids. In addition, many whitefly species harbor additional endosymbionts which may potentially further supplement their host's diet. To test this hypothesis, genomes of several endosymbionts of the whiteflies Aleurodicus dispersus, Aleurodicus floccissimus and Trialeurodes vaporariorum were analyzed. In addition to Portiera, all three species were found to harbor one Arsenophonus and one Wolbachia endosymbiont. A comparative analysis of Arsenophonus genomes revealed that although all three are capable of synthesizing B vitamins and cofactors, such as pyridoxal, riboflavin, or folate, their genomes and phylogenetic relationship vary greatly. Arsenophonus of A. floccissimus and T. vaporariorum belong to the same clade, and display characteristics of facultative endosymbionts, such as large genomes (3 Mb) with thousands of genes and pseudogenes, intermediate GC content, and mobile genetic elements. In contrast, Arsenophonus of A. dispersus belongs to a different lineage and displays the characteristics of a primary endosymbiont—a reduced genome (670 kb) with ~400 genes, 32% GC content, and no mobile genetic elements. However, the presence of 274 pseudogenes suggests that this symbiotic association is more recent than other reported primary endosymbionts of hemipterans. The gene repertoire of Arsenophonus of A. dispersus is completely integrated in the symbiotic consortia, and the biosynthesis of most vitamins occurs in shared pathways with its host. In addition, Wolbachia endosymbionts have also retained the ability to produce riboflavin, flavin adenine dinucleotide, and folate, and may make a nutritional contribution. Taken together, our results show that Arsenophonus hold a pivotal place in whitefly nutrition by their ability to produce B vitamins

Data from: Projecting pest population dynamics under global warming: the combined effect of inter- and intra-annual variations

The typical short generation length of insects makes their population dynamics highly sensitive not only to mean annual temperatures but also to their intra-annual variations. To consider the combined effect of both thermal factors under global warming, we propose a modeling framework that links general circulation models (GCMs) with a stochastic weather generator and population dynamics models to predict species population responses to inter- and intra-annual temperature changes. This framework was utilized to explore future changes in populations of Bemisia tabaci, an invasive insect pest-species that affects multiple agricultural systems in the Mediterranean region. We considered three locations representing different pest status and climatic conditions: Montpellier (France), Seville (Spain), and Beit-Jamal (Israel). We produced ensembles of local daily temperature realizations representing current and future (mid-21st century) climatic conditions under two emission scenarios for the three locations. Our simulations predicted a significant increase in the average number of annual generations and in population size, and a significant lengthening of the growing season in all three locations. A negative effect was found only in Seville for the summer season, where future temperatures lead to a reduction in population size. High variability in population size was observed between years with similar annual mean temperatures, suggesting a strong effect of intra-annual temperature variation. Critical periods were from late spring to late summer in Montpellier and from late winter to early summer in Seville and Beit-Jamal. Although our analysis suggested that earlier seasonal activity does not necessarily lead to increased populations load unless an additional generation is produced, it is highly likely that the insect will become a significant pest of open-fields at Mediterranean latitudes above 40° during the next 50 years. Our simulations also implied that current predictions based on mean temperature anomalies are relatively conservative and it is better to apply stochastic tools to resolve complex responses to climate change while taking natural variability into account. In summary, we propose a modeling framework capable of determining distinct intra-annual temperature patterns leading to large or small population sizes, for pest risk assessment and management planning of both natural and agricultural ecosystems

Seville-BCC-CSM1.1-RCP4.5

Downscaled (bias-corrected) daily temperature data (150 simulations for 10 years) based on the BCC-CSM1.1 CMIP5 model. Seville station Spain. RCP4.5 climate scenario

Resistance to insecticides in the TYLCV vector, Bemisia tabaci

R Horowitz, Shai Morin, and Arthur Denholm, 'Resistance to insecticides in the TYLCV vector, Bemisia tabaci' in, Henryk Czosnek Ed., Tomato Yellow Leaf Curl Virus Disease, (Netherlands: Springer, 2007), ISBN: 978-1-4020-4768-

Montpellier-BCC-CSM1.1-Current

Downscaled (bias-corrected) daily temperature data (150 simulations for 10 years) based on the BCC-CSM1.1 CMIP5 model. Montpellier station France. Current climate scenario

ModelOutput

Mean temperature and population dynamic model output (generation number, log population size and growth season length) for each climate model, scenario, station and simulated year