To date, thousands of microRNAs (miRNAs) and their precursors (pre-miRNAs) have been identified in insects and their nucleotide sequences deposited in the miRBase database. In the present work, we have systematically analyzed, utilizing bioinformatics tools, the featural differences between human and insect pre-miRNAs, as well as differences across 24 insect species. Results showed that the nucleotide composition, sequence length, nucleotides preference and secondary structure features between human and insects were different. Subsequently, with the aid of three available SVM-based prediction programs, pre-miRNA sequences were evaluated and given corresponding scores. Thus it was found that of 2633 sequences from the 24 chosen insect species, 2229 (84.7%) were successfully recognized by the Mirident classifier, higher than Triplet-SVM (72.5%) and PMirP (72.6%). In contrast, four species, including the domesticated silkworm, Bombyx mori L., the fruit fly, Drosophila melanogaster Meigen, the honeybee, Apis mellifera L. and the red flour beetle, Tribolium castaneum (Herbst), were found to be largely responsible for the poor performance of some sequence matching. Compared with other species, B. mori especially showed the worst performance with the lowest average MFE index (0.73). Collectively these results pave the way for understanding specificity and diversity of miRNA precursors in insects, and lay the foundation for the further development of more suitable algorisms for insects., Li, Jisheng ... [et al.]., and Obsahuje seznam literatury
Tato studie pojednává o rané fázi mikroskopického zkoumání přírody, které ve svém díle Micrographia (1665) představil Robert Hooke (1635–1703). Vzhledem k obsáhlosti díla se zaměřuje na pasáže, které Hooke věnoval výzkumu hmyzu. Předmětem analýzy je především metodologie Hookova výzkumu: způsob, jakým tento experimentátor využíval mikroskop ke zkoumání mravenců, much, komárů a jiného hmyzu. Dále je pozornost věnována způsobu, jakým Hooke představoval výsledky svého pozorování, tedy popisům a ilustracím hmyzu. A konečně, příspěvek se také pokouší vyložit vybrané záznamy mikroskopických pozorování v Micrographii a objasnit jejich vazbu na filosofickou a náboženskou interpretaci přírody sedmnáctého století., The aim of the study is to discuss the early microscopic examination of nature, introduced by Robert Hooke (1635–1703) in his work Micrographia (1665). Considering the complexity of his work, the paper focuses on passages concerning Hooke’s research of insects. The object of analysis is above all Hooke’s methodology of research: the way in which the experimenter used the microscope to study ants, flies, mosquitoes and other insects. Attention is also paid to the way in which Hooke presented the results of his observation, i.e. to his descriptions and illustrations of insects. Finally, the study also tries to interpret selected records of microscopic observations in Micrographia and clarify their relation to philosophical and religious interpretations of nature in seventeenth century., and Monika Bečvářová.
The mouthparts of the spoon-winged lacewing Nemoptera sinuata are adapted for the uptake of pollen and nectar. Form and function of the mouthparts are described, and the technique of food uptake is discussed in context with flower-visiting behaviour and floral architecture of the preferred flowers. The maxillae are the main organs for food uptake. The brush-shaped laciniae, galeae and maxillary palpi form a functional unit which can be extended by the action of the cardo-stipes joint. Video analyses of the mouthpart movements distinguished different patterns of maxillary motions which occur in nectar feeding or pollen collecting. The flower-visiting behaviour and the specialised mouthparts of the Nemopteridae are derived traits which probably evolved from predatory and biting/chewing mouthparts within the Neuroptera.
As urbanisation is set to continue, understanding the impact on wildlife becomes increasingly important if we are to be able to conserve biodiversity. As an excellent group of bioindicators, invertebrates can allow us to understand some of the forces in urban areas which impact upon biodiversity and wildlife populations. This paper discusses some of the trends in the abundance, diversity and richness of invertebrates related to urbanisation and the specific urban environmental and traffic factors which may be at play., Elizabeth L. Jones, Simon R. Leather., and Obsahuje seznam literatury
By means of a tracer assay using a labeled synthetic angiotensin converting enzyme (ACE) substrate hippurylglycylglycine, we have detected high ACE activity in the testes of the African migratory locust, Locusta migratoria. Lower, but significant, ACE activity was observed in midgut and hemolymph. In a two-step purification procedure involving anion exchange and gel permeation chromatography, we have purified LomACE from the locust testes. The enzyme of approximately 80 kDa shows substantial amino-acid sequence homology with ACE from both vertebrate and invertebrate origin. The ACE identity of the purified enzyme was further confirmed by cDNA cloning of the Locusta ACE fragment, which, after in silico translation, revealed a mature protein of 623 amino acids with a large structural similarity to other known ACE proteins.
Climate features that influence life cycles, notably severity, seasonality, unpredictability and variability, are summarized for different polar zones. The zones differ widely in these factors and how they are combined. For example, seasonality is markedly reduced by oceanic influences in the Subantarctic. Information about the life cycles of Arctic and Antarctic arthropods is reviewed to assess the relative contributions of flexibility and programming to life cycles in polar regions. A wide range of life cycles occurs in polar arthropods and, when whole life cycles are considered, fixed or programmed elements are well represented, in contrast to some recent opinions that emphasize the prevalence of flexible or opportunistic responses. Programmed responses ale especially common for controlling the appearance of stages that are sensitive to adverse conditions, such as the reproductive adult. The relative contribution of flexibility and programming to different life cycles is correlated with taxonomic affinity (which establishes the general lifecycle framework for a species), and with climatic zone, the habitats of immature and adult stages, and food., Hugh V. Danks, and Lit
Some previous work on arthropod development is insufficiently detailed or incompletely reported. Much of the published information in this area is of limited use for the general analysis of life cycles. These difficulties arise primarily because many experiments do not control fully for the strain of the material (and even its specific identity) nor for rearing conditions, do not adequately take account of the complexity of life cycles and their stages, or are restricted to only part of the life cycle. For example, 285such factors as variable numbers of instars, sexual differences, abbreviated or hidden stages and dormancies may mean that the "average durations" reported apply to an unknown mixture of developmental types. Nor are experiments always designed or results reported and analysed in a logical and transparent manner. Undefined terms may obscure what actual developmental intervals were measured. Highly derived developmental or demographic measures may obscure core data. Statistical information may be inadequate. Such pitfalls are reviewed here, suggesting ways to ensure that results on the duration of development are both valid for specific studies and more widely useful. General experimental difficulties, recommended background information that should be provided, recommended life-cycle intervals and their terminology, and recommended ways to report numerical and statistical information are briefly summarized in tabular form.
Many factors contribute to the 'invasive potential' of species or populations. It has been suggested that the rate of genetic evolution of a species and the amount of genetic diversity upon which selection can act may play a role in invasiveness. In this study, we examine whether invasive species have a higher relative pace of molecular evolution as compared with closely related non-invasive species, as well as examine the genetic diversity between invasive and closely related species. To do this, we used mitochondrial cytochrome c oxidase subunit I sequences of 35 species with a European native range that are invasive in North America. Unique to molecular rate studies, we permuted across sequences when comparing each invasive species with its sister clade species, incorporating a range of recorded genetic variation within species using 405,765 total combinations of invasive, sister, and outgroup sequences. We observed no significant trend in relative molecular rates between invasive and non-invasive sister clade species, nor in intraspecific genetic diversity, suggesting that differences in invasive status between closely related lineages are not strongly determined by the relative overall pace of genetic evolution or molecular genetic diversity. We support previous observations of more often higher genetic diversity in native than invaded ranges using available data for this genetic region.
Polyhydroxylated derivatives of 6-keto,7-dehydrocholesterol (ecdysteroids) are common constituents of various plants.
In 1965, they were accidentally discovered in the search for the insect moulting hormone. These biologically important natural
compounds are neither insect hormones nor inducers of insect ecdysis. Due to their strong anabolic, vitamin D-like effects in insects, domestic animals and humans, I propose the use of the arbitrary term vitamin D1
. The present paper describes the effects
of vitamin D1
on the growth and regeneration of excised epidermal cells of the tobacco hornworm, Manduca sexta (Sphingidae).
The periods of programmed cell death and cell proliferation (histolysis and histogenesis, respectively) exactly coincide in insects
with endogenous peaks of increased concentration of vitamin D1
. Epidermal cells communicate with each other, creating a mutually integrated tissue, connected by mechanical, chemical, electrical, ionic or other so far incompletely known factors. After natural
cell death, or after the artifi cial removal of some epidermal cells, the neighbouring cells that lose communication integrity, begin
to divide mitotically to replace the disconnected part. Cell divisions are arrested as soon as the integrity of the living tissue is
established. During insect ontogeny, the application of juvenile hormone causes regenerating epidermal cells to repeat the previous morphogenetic programme (i.e., development of patches of larval tissue on the body of a pupa, or metathetely). Conversely,
the application of vitamin D1
(20-hydroxyecdysone) caused the regenerating cells to prematurely execute a future morphogenetic
programme (i.e., development of patches of pupal tissue on the body of a larva, or prothetely). Among the key features of insect
regeneration, is the arrest of cell divisions when tissues resume living cell-to-cell integrity. This prevents the formation of aberrant groups of cells, or tumours. It is well established that the main physiological systems of insects (e.g., circulatory, respiratory,
neuro-endocrine) are structurally and functionally similar to corresponding systems in humans. Thus the basic principles of cell
regeneration and the role of vitamin D1
in insects may also be valid for humans. The common vitamins D2
(ergocalciferol) or D3
(cholecalciferol), are exclusively lipid soluble secosterols, which require activation by UV irradiation and hydroxylation in the liver.
By contrast, the neglected vitamin D1
is a natural derivative of polyhydroxylated 7-dehydrocholesterol of predominantly plant origin, which is both partly a water and partly a lipid soluble vitamin. It neither requires UV irradiation, nor hydroxylation due to 6 or
7 already built-in hydroxylic groups. Like other vitamins, it enters insect or human bodies in plant food or is produced by intestinal
symbionts. Vitamin D1
causes strong anabolic, vitamin D-like effects in domestic animals and in humans. I am convinced that
avitaminosis associated with a defi ciency of vitamin D1 in human blood may be responsible for certain hitherto incurable human
diseases, especially those related to impaired nerve functions and somatic growth, aberrant cell regeneration or formation of
malignant tumours.