93 research outputs found
New country and state records, and other notes for Mexican Buprestidae (Coleoptera)
Treatment is provided for 224 species and subspecies in the genera Acherusia, Acmaeodera, Actenodes, Agaeocera, Agrilus, Anthaxia, Brachys, Buprestis, Chalcangium, Chrysobothris, Colobogaster, Cyphothorax, Dicerca, Dismorpha, Euchroma, Hiperantha, Hylaeogena, Leiopleura, Lius, Mixochlorus, Omochyseus, Pachyschelus, Polycesta, Psiloptera, Spectralia, Taphrocerus, Tetragonoschema, Thrincopyge, Trypantius and Tyndaris. Of these, 44 are recorded for the first time from Mexico and 175 represent new state records. Adult host and/or habitat information is provided, usually from the label data, for 93 of the taxa. Larval host records are indicated for Chrysobothris analis LeConte, C. capitata Gory and Laporte, C. multistigmosa (Mannerheim) and C. sallei Waterhouse. Acmaeodera sinaloensis Duges has been discovered to breed in bamboo. A major taxonomic character of C. multistigmosa is discussed
Distribuição espacial de imaturos de Phyllocnistis citrella (Lepidoptera, Gracillariidae) nos brotos e nas folhas de laranjeiras, Citrus sinensis var. Valência, mantidas sob dois sistemas de cultivo
Mechanical and Assembly Units of Viral Capsids Identified via Quasi-Rigid Domain Decomposition
Key steps in a viral life-cycle, such as self-assembly of a protective protein container or in some cases also subsequent maturation events, are governed by the interplay of physico-chemical mechanisms involving various spatial and temporal scales. These salient aspects of a viral life cycle are hence well described and rationalised from a mesoscopic perspective. Accordingly, various experimental and computational efforts have been directed towards identifying the fundamental building blocks that are instrumental for the mechanical response, or constitute the assembly units, of a few specific viral shells. Motivated by these earlier studies we introduce and apply a general and efficient computational scheme for identifying the stable domains of a given viral capsid. The method is based on elastic network models and quasi-rigid domain decomposition. It is first applied to a heterogeneous set of well-characterized viruses (CCMV, MS2, STNV, STMV) for which the known mechanical or assembly domains are correctly identified. The validated method is next applied to other viral particles such as L-A, Pariacoto and polyoma viruses, whose fundamental functional domains are still unknown or debated and for which we formulate verifiable predictions. The numerical code implementing the domain decomposition strategy is made freely available
Changes in Lysozyme Flexibility upon Mutation Are Frequent, Large and Long-Ranged
We investigate changes in human c-type lysozyme flexibility upon mutation via a Distance Constraint Model, which gives a statistical mechanical treatment of network rigidity. Specifically, two dynamical metrics are tracked. Changes in flexibility index quantify differences within backbone flexibility, whereas changes in the cooperativity correlation quantify differences within pairwise mechanical couplings. Regardless of metric, the same general conclusions are drawn. That is, small structural perturbations introduced by single point mutations have a frequent and pronounced affect on lysozyme flexibility that can extend over long distances. Specifically, an appreciable change occurs in backbone flexibility for 48% of the residues, and a change in cooperativity occurs in 42% of residue pairs. The average distance from mutation to a site with a change in flexibility is 17–20 Å. Interestingly, the frequency and scale of the changes within single point mutant structures are generally larger than those observed in the hen egg white lysozyme (HEWL) ortholog, which shares 61% sequence identity with human lysozyme. For example, point mutations often lead to substantial flexibility increases within the β-subdomain, which is consistent with experimental results indicating that it is the nucleation site for amyloid formation. However, β-subdomain flexibility within the human and HEWL orthologs is more similar despite the lowered sequence identity. These results suggest compensating mutations in HEWL reestablish desired properties
Ants visit nectaries of Epidendrum denticulatum (Orchidaceae) in a Brazilian rainforest: effects on herbivory and pollination
Viral capsids: Mechanical characteristics, genome packaging and delivery mechanisms
The main functions of viral capsids are to protect, transport and deliver their genome. The mechanical properties of capsids are supposed to be adapted to these tasks. Bacteriophage capsids also need to withstand the high pressures the DNA is exerting onto it as a result of the DNA packaging and its consequent confinement within the capsid. It is proposed that this pressure helps driving the genome into the host, but other mechanisms also seem to play an important role in ejection. DNA packaging and ejection strategies are obviously dependent on the mechanical properties of the capsid. This review focuses on the mechanical properties of viral capsids in general and the elucidation of the biophysical aspects of genome packaging mechanisms and genome delivery processes of double-stranded DNA bacteriophages in particular
Characterization of the larval stages of Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) using head capsule width
Coexistência entre Turdus leucomelas Vieillot, 1818 e Turdus rufiventris Vieillot, 1818 (Aves: Passeriformes) em um fragmento urbano de floresta com araucárias, Sul do Brasil
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