121 research outputs found
The genome of a tortoise herpesvirus (testudinid herpesvirus 3) has a novel structure and contains a large region that is not required for replication in vitro or virulence in vivo
Testudinid herpesvirus 3 (TeHV-3) is the causative agent of a lethal disease affecting several tortoise species. The threat that this virus poses to endangered animals is focusing efforts on characterizing its properties, in order to enable the development of prophylactic methods. We have sequenced the genomes of the two most studied TeHV-3 strains (1976 and 4295). TeHV-3 strain 1976 has a novel genome structure and is most closely related to a turtle herpesvirus, thus supporting its classification into genus Scutavirus, subfamily Alphaherpesvirinae, family Herpesviridae. The sequence of strain 1976 also revealed viral counterparts of cellular interleukin-10 and semaphorin, which have not been described previously in members of subfamily Alphaherpesvirinae. TeHV-3 strain 4295 is a mixture of three forms (m1, m2, and M), in which, in comparison to strain 1976, the genomes exhibit large, partially overlapping deletions of 12.5 to 22.4 kb. Viral subclones representing these forms were isolated by limiting dilution, and each replicated in cell culture comparably to strain 1976. With the goal of testing the potential of the three forms as attenuated vaccine candidates, strain 4295 was inoculated intranasally into Hermann's tortoises (Testudo hermanni). All inoculated subjects died, and PCR analyses demonstrated the ability of the m2 and M forms to spread and invade the brain. In contrast, the m1 form was detected in none of the organs tested, suggesting its potential as the basis of an attenuated vaccine candidate. Our findings represent a major step towards characterizing TeHV-3 and developing prophylactic methods against it. IMPORTANCE: Testudinid herpesvirus 3 (TeHV-3) causes a lethal disease in tortoises, several species of which are endangered. We have characterized the viral genome, and used this information to take steps towards developing an attenuated vaccine. We have sequenced the genomes of two strains (1976 and 4295), compared their growth in vitro, and investigated the pathogenesis of strain 4295, which consists of three deletion mutants. The major findings are: (i) TeHV-3 has a novel genome structure; (ii) its closest relative is a turtle herpesvirus; (iii) it contains interleukin-10 and semaphorin genes, the first time these have been reported in an alphaherpesvirus; (iv) a sizeable region of the genome is not required for viral replication in vitro or virulence in vivo; and (v) one of the components of strain 4295, which has a deletion of 22.4 kb, exhibits properties indicating that it may serve as the starting point for an attenuated vaccine
Seasonal variation in the relative dominance of herbivore guilds in an African savanna
African savannas are highly seasonal with a diverse array of both mammalian and invertebrate herbivores, yet herbivory studies have focused almost exclusively on mammals. We conducted a 2-yr exclosure experiment in South Africa's Kruger National Park to measure the relative impact of these two groups of herbivores on grass removal at both highly productive patches (termite mounds) and in the less productive savanna matrix. Invertebrate and mammalian herbivory was greater on termite mounds, but the relative importance of each group changed over time. Mammalian offtake was higher than invertebrates in the dry season, but can be eclipsed by invertebrates during the wet season when this group is more active. Our results demonstrate that invertebrates play a substantial role in savanna herbivory and should not be disregarded in attempts to understand the impacts of herbivory on ecosystems
Leaf response to water deficits in soybeans
Soybeans [Glycine max (L.) Merrill cv. Wayne] plants were subjected to an extended drying cycle in the field to investigate the leaf sensitivity to water deficits. Soybeans in irrigated plots were superior to those in non-irrigated plots in the average size and number of leaflets per plant. Apparent differences in the leaf area distributions in the canopy seemed to be mediated by moisture stress effects associated with leaf senescence and light penetration in the lower depths of the canopy. A major decrease in leaf enlargement occurred near a leaf-water potential of -8 bars, and at - 12 bars, the growth was completely halted. Similar decreases were observed at a stomatal conductance of 0.4 cm/s and at 0.2 cm/s no enlargement was observe
A method to determine the displacement velocity field in the apical region of the Arabidopsis root
In angiosperms, growth of the root apex is determined by the quiescent centre. All tissues of the root proper and the root cap are derived from initial cells that surround this zone. The diversity of cell lineages originated from these initials suggests an interesting variation of the displacement velocity within the root apex. However, little is known about this variation, especially in the most apical region including the root cap. This paper shows a method of determination of velocity field for this region taking the Arabidopsis root apex as example. Assuming the symplastic growth without a rotation around the root axis, the method combines mathematical modelling and two types of empirical data: the published velocity profile along the root axis above the quiescent centre, and dimensions of cell packet originated from the initials of epidermis and lateral root cap. The velocities, calculated for points of the axial section, vary in length and direction. Their length increases with distance from the quiescent centre, in the root cap at least twice slower than in the root proper, if points at similar distance from the quiescent centre are compared. The vector orientation depends on the position of a calculation point, the widest range of angular changes, reaching almost 90°, in the lateral root cap. It is demonstrated how the velocity field is related to both distribution of growth rates and growth-resulted deformation of the cell wall system. Also changes in the field due to cell pattern asymmetry and differences in slope of the velocity profile are modelled. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00425-012-1707-x) contains supplementary material, which is available to authorized users
Determination of 4-Chloroindole-3-Acetic Acid Methyl Ester in Lathyrus Vicia and Pisum by Gas Chromatography - Mass Spectrometry
Simple Identification of the Neutral Chlorinated Auxin in Pea by Thin Layer Chromatography
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