Features related to anther opening in Solanum species (Solanaceae)

The mode of anther opening and the morphological and histological variability of the stomium are described in 30 Solanum species. Poricidal, poricidal‐longitudinally dehiscing and longitudinally dehiscing anthers are observed. In the three types, the stomium may be diverse with regard to shape and histological characteristics before opening, but is always composed of small epidermal cells as the sole anther wall layer; the stomial cells may be differentiated only in part of the anther length. Particular crescent‐shaped structures in the epidermis, called ‘ridges’, are observed to line the stomium in most species. These ridges may be related to the stomium opening, working together with the cells with thickened walls of the anther. Cells with thickened walls are developed in the endothecium, middle layers and/or connective tissue at the apical end of the anther, surrounding the pore; only in the longitudinally dehiscing anthers of S. nitidum does an endothecium with thickened cell walls develop along its entire length. At least two histological features (the differentiation of small stomial epidermal cells as a unique layer, and the distribution of cells with thickened walls) seem to constrain the form of the open stomium. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 344–354.     

Efficacy of entomopathogenic nematodes against neonate larvae of <Emphasis Type="Italic">Capnodis tenebrionis</Emphasis> (L.) (Coleoptera: Buprestidae) in laboratory trials

The efficacy of five entomopathogenic nematode strains of the families Steinernematidae and Heterorhabditidae was tested against the neonate larvae of Capnodis tenebrionis. The nematode strains screened included two of Steinernema carpocapsae (Exhibit and M137), and one each of S. feltiae (S6), S. arenarium (S2), and Heterorhanditis bacteriophora (P4). Exposure of neonate larvae of Capnodis to 10 and 150 infective juveniles (IJs) per larva (equivalent to 3 and 48 IJs/cm² respectively) in test tubes with sterile sand, resulted in mortality between 60–91% and 96–100%, respectively. At a concentration of 150 IJs/larva, all of the nematode strains were highly virulent. Both S. carpocapsae strains (Exhibit and M137) caused infection and mortality to larvae more quickly than the other strains. However, at a lower concentration assay (10 IJs/larva), S. arenarium was the most virulent strain. The penetration rate as an indicator of entomopathogenic nematode infection was also evaluated. The highest value was recorded for S. arenarium (36%), followed by H. bacteriophora (30.6%), S. feltiae (23.1%), and S. carpocapsae (20.7%).     

Andean bear Tremarctos ornatus natural history and conservation

• 1 A wealth of information has been generated for the Andean bear Tremarctos ornatus during the past four decades, and a thorough review of the species' natural history, ecology and conservation is provided here.
• 2 The Andean bear is the only remaining bear species in South America. Evolutionarily, it is the youngest of all ursids and the only remnant taxon within the subfamily Tremarctinae. The species is distributed throughout the Andes mountain range from Venezuela to Bolivia, but the limits of its current and past range are uncertain.
• 3 The species is polyestrous, capable of delayed implantation and a facultative seasonal breeder. Genetic information is scarce, and species‐specific markers need to be developed for a more appropriate assessment of the genetic structure of wild populations.
• 4 Andean bears inhabit a wide variety of habitats across the Andes including different forest types and high‐elevation grasslands. They are omnivorous with a frugivorous/folivorous emphasis that is reflected by adaptations of the typical tremarctine mandible.
• 5 Andean bears are vulnerable to extinction due to land conversion and poaching. Efforts have been made to protect them, but threats have not been reduced significantly. Therefore, the species is expected to move faster towards extinction than any other carnivore in the region.

     

Comparative wood anatomy in Abietoideae (Pinaceae)

This study, which includes 51 species and six genera of subfamily Abietoideae (Pinaceae), assesses the systematic significance of the wood structure in this group. In particular, the presence of normal and traumatic resin canals, the ray structure and the axial parenchyma constitute phylogenetically informative features. Comparative wood anatomy of Abietoideae clearly supports the monophyly of the genera Abies–Cedrus–Keteleeria–Nothotsuga–Pseudolarix–Tsuga, all of which have axial parenchyma with nodular transverse end walls in the regions of growth ring boundaries, crystals in the ray parenchyma and pitted horizontal and nodular end walls of ray parenchyma cells. Axial resin canals support a subdivision of the subfamily into two groups: Abies, Cedrus, Pseudolarix and Tsuga, without axial resin canals, and Keteleeria and Nothotsuga, with axial resin canals and a specific arrangement of traumatic axial resin canals. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 184–196.     

Activation of geminivirus V‐sense promoters in roots is restricted to nematode feeding sites

Obligate sedentary endoparasitic nematodes, such as the root‐knot and cyst nematodes, elicit the differentiation of specialized nematode nurse or feeding cells [nematode feeding sites (NFS), giant cells and syncytia, respectively]. During NFS differentiation, marked changes in cell cycle progression occur, partly similar to those induced by some geminiviruses. In this work, we describe the activation of V‐sense promoters from the Maize streak virus (MSV) and Wheat dwarf virus (WDV) in NFS formed by root‐knot and cyst nematodes. Both promoters were transiently active in microinjection experiments. In tobacco and Arabidopsis transgenic lines carrying promoter–β‐glucuronidase fusions, the MSV V‐sense promoter was activated in the vascular tissues of aerial plant parts, primarily leaf and cotyledon phloem tissue and some floral structures. Interestingly, in roots, promoter activation was restricted to syncytia and giant cells tested with four different nematode populations, but undetectable in the rest of the root system. As the activity of the promoter in transgenic rootstocks should be restricted to NFS only, the MSV promoter may have utility in engineering grafted crops for nematode control. Therefore, this study represents a step in the provision of some of the much needed additional data on promoters with restricted activation in NFS useful in biotechnological nematode control strategies.     

Assessing effects of water abstraction on fish assemblages in Mediterranean streams

1. Water abstraction strongly affects streams in arid and semiarid ecosystems, particularly where there is a Mediterranean climate. Excessive abstraction reduces the availability of water for human uses downstream and impairs the capacity of streams to support native biota. 2. We investigated the flow regime and related variables in six river basins of the Iberian Peninsula and show that they have been strongly altered, with declining flows (autoregressive models) and groundwater levels during the 20th century. These streams had lower flows and more frequent droughts than predicted by the official hydrological model used in this region. Three of these rivers were sometimes dry, whereas there were predicted by the model to be permanently flowing. Meanwhile, there has been no decrease in annual precipitation. 3. We also investigated the fish assemblage of a stream in one of these river basins (Tordera) for 6 years and show that sites more affected by water abstraction display significant differences in four fish metrics (catch per unit effort, number of benthic species, number of intolerant species and proportional abundance of intolerant individuals) commonly used to assess the biotic condition of streams. 4. We discuss the utility of these metrics in assessing impacts of water abstraction and point out the need for detailed characterisation of the natural flow regime (and hence drought events) prior to the application of biotic indices in streams severely affected by water abstraction. In particular, in cases of artificially dry streams, it is more appropriate for regulatory agencies to assign index scores that reflect biotic degradation than to assign ‘missing’ scores, as is presently customary in assessments of Iberian streams.     

Effects of Glyphosate on Isolated Maize Mitochondria

The effects of the herbicide glyphosate (K⁺ salt) on isolatedmaize mitochondria have been investigated. Protein synthesis,oxygen uptake (state 3 and state 4 respiration) and passiveswelling were inhibited at concentrations in the 10^–6–10^–2M range. No decrease of the respiratory control ratio (RCR)or stimulation of ATPase activity by glyphosate (K+ salt) wereobserved. It is concluded that the previously reported decreaseof the RCR and ATPase stimulation by glyphosate (isopropylaminesalt) were probably due to the isopropylamine moiety or to impuritiesof the technical product. Key words: Glyphosate, Herbicide action, Maize, Mitochondria     

Seroprevalence of Trypanosoma cruzi and Leishmania mexicana in Free‐Ranging Howler Monkeys in Southeastern Mexico

Natural infection of wild mammals by protozoa parasites is quite common in nature. For Neotropical Primates different infections of parasites that are etiological agent of disease in human have been identified. In particular, infections by Trypanosoma cruzi and Leishmania sp., have been reported for some New World primate species, but there are no reports of infection with these parasites in any primate species in Mexico. A serological study was conducted on two howler monkey species (Alouatta pigra and A. palliata) from the Mexican states of Campeche and Tabasco. A total of 55 serum samples (20 samples from A. pigra, 20 samples from A. palliata, and 15 samples from semifree ranging A. palliata of Los Tuxtlas, Veracruz as negative controls) were analyzed for the detection of immunoglobulin G antibodies against T. cruzi and Leishmania mexicana through enzyme linked immunosorbent assay test, indirect immunofluorescence assay and Western blot. The overall prevalence of antibodies in howler monkeys was 17.5% for T. cruzi and 30% for L. mexicana. Our results also indicate that A. pigra is more susceptible to develop leishmaniasis than A. palliata. Finally, the finding of positive serology in these primates should be given serious consideration for public health, given the potential role of these primate species as wild reservoirs for these diseases and the increasing contact of monkeys with human populations due to habitat loss and fragmentation. Am. J. Primatol. 75:161‐169, 2013. © 2012 Wiley Periodicals, Inc.     

Chloroplast protection in plum pox virus‐infected peach plants by L‐2‐oxo‐4‐thiazolidine‐carboxylic acid treatments: effect in the proteome

Sharka, a disease caused by plum pox virus (PPV), has a significant economic impact on fruit tree production. In this work, we analysed the effect of (2,1,3)‐benzothiadiazole (BTH) and L‐2‐oxo‐4‐thiazolidine‐carboxylic acid (OTC) on plant growth and virus content. OTC reduced sharka symptom, stimulated plant growth and alleviated PPV‐induced oxidative stress, indicated by a lack of changes in some oxidative stress parameters. PPV infection reduced chloroplast electron transport efficiency. However, in the presence of BTH or OTC, no changes in the chlorophyll fluorescence parameters were observed. PPV produced an alteration in chloroplast ultrastructure, giving rise to a decrease in starch contents that was less dramatic in OTC‐treated plants. Furthermore, PPV reduced the abundance of proteins associated with photosynthesis, carbohydrate and amino acid metabolism and photorespiration. These changes did not take place in OTC‐treated plants, and increases in the expression of proteins related with the aforementioned processes, including ADP‐glucose pyrophosphorylase, were produced, which correlated with the lower decrease in starch contents observed in PPV‐infected plants treated with OTC. The results suggested that OTC treatment provides protection to the photosynthetic machinery and/or the chloroplast metabolism in PPV‐infected peaches. Thus, OTC could have practical implications in agriculture in improving the vigour of different plant species as well as in immunizing plants against pathogens.