Molecular detection of nematicidal crystalliferous Bacillus thuringiensis strains of Iran and evaluation of their toxicity on free-living and plant-parasitic nematodes

The characterization of nematode-effective strains and cry genes in the Iranian Bacillus thuringiensis (Bt) collection (70 isolates) is presented. Characterization was based on PCR analysis using 12 specific primers for cry5, cry6, cry12, cry13, cry14, and cry21 genes encoding proteins active against nematodes, crystal morphology, and protein band patterns as well as their nematicidal activity on root-knot nematode (Meloidogyne incognita) and two free-living nematodes (Chiloplacus tenuis and Acrobeloides enoplus). PCR results with primers for these genes showed that 22 isolates (31.5%) contain a minimum of one nematode-active cry gene. Strains containing the cry6 gene were the most abundant and represent 22.8% of the isolates. Bt strains harboring cry14 genes were also abundant (14.2%). cry21 and cry5 genes were less abundant, found in 4.2% and 2.8% of the strains, respectively. In total, six different nematode-active cry gene profiles were detected in this collection. Four isolates did not show the expected PCR product size for cry5, cry6, and cry21 genes; they might contain potentially novel insecticidal crystal protein genes. Twenty-two Bt isolates containing nematode-active cry genes were selected for preliminary bioassays on M. incognita. Based on these bioassays, four isolates were selected for detailed bioassays. Isolates YD5 and KON4 at 2 x 10(8) CFU/mL concentrations showed 77% and 81% toxicity on M. incognita, respectively. The free-living nematodes C. tenuis and A. enoplus were more susceptible and the highest mortality was observed within 48 h of incubation at all of the concentrations tested. Maximum mortality was recorded for isolates SN1 and KON4 at 2 x 10(8) CFU/mL concentrations and resulted in 68% and 77% adults deaths of C. tenuis and 68% and 72% for A. enoplus, respectively. Our results showed that PCR is a useful technique for toxicity prediction of nematicidal Bt isolates.     

Body mass and behavior in Swiss mice subjected to continuous or discontinuous food restriction and refeeding

Food restriction (FR) is hypothesized to decrease body fat content of an animal and thus prevent obesity. However, the response of energy budget to a continuous (CFR) or discontinuous FR (DFR) remains inconsistent. In the present study, effects of CFR or DFR and refeeding on energy budget and behavior were examined in male Swiss mice. CFR significantly decreased the energy expenditure associated with basal metabolic rate (BMR) and activity behavior, but not sufficiently to compensate for energy deficit and thus resulted in lower body mass and fat content. DFR mice had a significantly higher food intake on ad libitum days and showed increases in BMR and activity after 4 weeks’ DFR, which might resulted in lower body mass and less body fat than controls. After being refed ad libitum, both CFR and DFR mice had similar body mass, BMR, and behavioral patterns to controls but had 95% and 75% higher fat content. This suggested that not only CFR but also DFR would be a significant factor in the process of obesity for animals that were refed ad libitum. It also indicated that food restriction interrupted many times by periods of ad libitum feeding had the same long-term effects like continuous underfeeding.     

Callus,shoot and hairy root formation in vitro as affected by the sensitivity to auxin and ethylene in tomato mutants

We analyzed the impact of ethylene and auxin disturbances on callus, shoots and Agrobacterium rhizogenes-induced hairy root formation in tomato (Solanum lycopersicum L.). The auxin low-sensitivity dgt mutation showed little hairy root initiation, whereas the ethylene low-sensitivity Nr mutation did not differ from the control Micro-Tom cultivar. Micro-Tom and dgt hairy roots containing auxin sensitivity/biosynthesis rol and aux genes formed prominent callus onto media supplemented with cytokinin. Under the same conditions, Nr hairy roots did not form callus. Double mutants combining Rg1, a mutation conferring elevated shoot formation capacity, with either dgt or Nr produced explants that formed shoots with little callus proliferation. The presence of rol + aux genes in Rg1 hairy roots prevented shoot formation. Taken together, the results suggest that although ethylene does not affect hairy root induction, as auxin does, it may be necessary for auxin-induced callus formation in tomato. Moreover, excess auxin prevents shoot formation in Rg1.     

Eel community structure,fluvial recruitment of <Emphasis Type="Italic">Anguilla marmorata</Emphasis> and indication for a weak local production of spawners from rivers of Réunion and Mauritius islands

Anguillid eels were sampled from permanent rivers in the Réunion and Mauritius islands, western Indian Ocean, with a standardized electrofishing method. A. marmorata was very dominant, corresponding to 91.7 and 90.7% of all the eels collected in Réunion and Mauritius, respectively. Three other species (A. mossambica, A. bicolor bicolor and A. nebulosa labiata) were also present in both islands. A. marmorata showed a strong altitudinal gradient of densities from the lower to upper zones, especially in the younger stages (TL <250 mm), while A. mossambica was only found in the upper zones and A. bicolor bicolor occurred only in the lower zones (A. nebulosa labiata was rare). The eel species composition in freshwaters of both islands is very similar because these two adjoining islands are located in the same trail of drifting marine larvae. Mean estimated eel biomasses were noticeably low (11.1 and 22.2 kg ha⁻¹ in Réunion and Mauritius islands, respectively), especially when compared to those of other tropical insular systems without any eel fishery (Comoros or Polynesia, more than 100 kg ha⁻¹). Nevertheless, the fluvial recruitment of A. marmorata seemed to be regular during the surveyed period, staggering from October to April. The obvious lack of large eels in Mauritius but more significantly in Réunion suggests a high pressure from traditional fishery, and the local reproductive turnover is uncertain. Because sexual maturation seems to occur at a large body size for A. marmorata, as for temperate species, the Réunion and Mauritius rivers may only have a weak contribution to the regional production of spawners. However, the giant mottled eel population in the western Indian Ocean is believed to be panmictic at the regional scale, and may not rely exclusively on these islands’ contribution. A comparison is made with those of freshwater systems in other tropical islands.     

A Global History of Australian Trees

Scholars studying the globalization of Australian trees have previously emphasized the rapid natural propagation of Australian trees outside of their native habitats, believing their success to be a reversal of “ecological imperialism” from the “new world” to the “old world.” This article argues that the expansion of Australian trees should not be viewed as a biological phenomenon, but as the result of a long-term attempt by powerful states and state-sponsored scientists to select and breed Australian species that could grow in a variety of climates and ecological conditions. Five non-biological factors largely determined the success of these attempts to grow Australian trees: the abundance or paucity of natural forests, state power, the amount of scientific research directed to planting Australian trees, the cost of labor, and the ability to utilize hardwood timbers and bark. This paper compares the use of Australian trees in Australia, India, and South Africa to demonstrate that biology was not the determining factor in the long-term success of many Australian genera and species.     

Do snakes represent the principal predatory threat to callitrichids? Fatal attack of a viper (<Emphasis Type=Italic>Bothrops leucurus</Emphasis>) on a common marmoset (<Emphasis Type=Italic>Callithrix jacchus</Emphasis>) in the Atlantic Forest of the Brazilian Northeast

A juvenile common marmoset (Callithrix jacchus) was attacked by a whitetail lancehead viper (Bothrops leucurus) while playing with other group members close to the ground at a site in northeastern Brazil. The attack was almost immediately fatal, but the viper was unable to ingest the body of the marmoset. After approximately 10 min, during which it attempted to swallow the marmoset a number of times, the viper moved away, abandoning the body. While raptors are the principal predators of callitrichids, this record reinforces the relative vulnerability of these primates to snakes in comparison with other platyrrhines, although the small number of recorded events precludes a more definitive analysis of the phenomenon.     

Chlorophyll fluorescence images demonstrate variable pathways in the effects of plasma membrane excitation on electron flow in chloroplasts of <Emphasis Type=Italic>Chara</Emphasis> cells

Chlorophyll fluorescence Imaging and Microscopy PAM fluorometry were applied to study spatial dynamics of photosystem II quantum yield ( DF/F_m￠ ) left( {Delta F/F_m^prime } right) and non-photochemical quenching (NPQ) in resting and electrically stimulated Chara corallina cells in the absence and presence of the hydrophilic electron acceptor methyl viologen (MV) in the external medium. Electrical excitation of the plasma membrane temporarily enhanced the heterogeneity of photosynthetic patterns under physiological conditions (in the absence of MV), but irreversibly eliminated these patterns in the presence of MV. These findings suggest that the action potential (AP) of the excitable plant cell affects the spatial patterns of photosynthesis and chlorophyll fluorescence through different pathways operated in the absence and presence of MV. Based on the extent of NPQ as an indicator of MV-dependent electron flow, it is supposed that MV cannot permeate into the chloroplasts of photosynthetically active “acid cell regions” but gains an immediate access to the stroma of these chloroplasts after triggering of an AP. The AP-triggered MV-dependent non-photochemical quenching in the chloroplasts of acidic cell regions was routinely observed at 0.1 mM Ca²⁺ in the medium but not at elevated (2 mM) external Ca²⁺ concentration. The results are interpreted in terms of competition between two permeant divalent ion species, Ca²⁺ and MV²⁺, for their passage through the voltage-gated calcium channels of the plasma membrane. It is proposed that the herbicidal activity of MV in characean cells, here serving as model object, can be manipulated by triggering AP and varying Ca²⁺ concentration in the environmental medium.     

Development of infant common marmosets’ (<Emphasis Type=Italic>Callithrix jacchus</Emphasis>) preference for their parents over adults from another group

Parent–offspring attachment is important for animals which have offspring that require parental care for their development. Infant attachment to the mother has been examined in macaques, but it remains poorly understood in common marmosets. Here, we examined the abilities of 14 common marmoset infants to show preference for their parents over adults from another group at the ages of 4, 10, and 15 weeks. Each infant was exposed to its parent and an adult from another group in an I-shaped maze. Although 4-week-old infants did not show a significant difference between approach behaviors toward their parents and other adults, 10- and 15-week-old infants approached and stayed longer near their parents than adults from another group. These results suggest selective approach behavior develops in marmosets by the age of 10 weeks.     

Convergent Patterns of Body Shape Differentiation in Four Different Clades of Poeciliid Fishes Inhabiting Sulfide Springs

We investigated replicated differentiation in four lineages of livebearing fishes (two with the genus Poecilia and two within Gambusia), which inhabit freshwater habitats and have also colonized sulfide springs in Oklahoma, Mexico, and Venezuela. Sulfide springs are characterized by extreme hypoxia and high concentrations of toxic hydrogen sulfide, which provide a strong source of divergent selection compared to adjacent non-sulfidic habitats. Using geometric morphometric analysis of body shape, we found that sulfide spring populations significantly differ from relatives from regular freshwater habitats in all four lineages investigated. Differentiation is characterized by strong patterns of convergent evolution, with sulfide spring populations consistently exhibiting an increase in head size, even though the magnitude and nature differences varied across lineages. Head size is strongly correlated with an increase in gill size in sulfide spring populations of the genus Poecilia, which facilitates efficient oxygen acquisition in the hypoxic H₂S-environment and directly affects survival. The convergent patterns of differentiation support previous findings about the effects of sulfide on trait evolution.     

<Emphasis Type=Italic>Treichelia dodii</Emphasis> (Campanulaceae s.s.), a new name in an endemic genus from Western Cape,South Africa

Examination of herbarium specimens and field studies showed that an unnamed taxon collected from Malmesbury, Western Cape for phylogenetic studies in the Campanulaceae, is a distinct species within the monotypic genus Treichelia. This species previously described as Wahlenbergia depressa Wolley-Dod is resurrected as Treichelia dodii to replace a later homonym. The differences between Treichelia longibracteata (H. Buek) Vatke and W. depressa are explained. A key to the species and a distribution map are provided.