Affinity purification and characterization of a seed lectin from Crotalaria medicaginea

Purification of lectin from the seeds of Crotalaria medicaginea Lamk by affinity chromatography on asialofetuin-linked amino activated silica, yielded a single band on non-denatured PAGE at pH 4.5 and 8.3 and, a single peak on HPLC size exclusion and cation exchange columns. The molecular mass of the native C. medicaginea lectin was determined to be 125 kDa by gel filtration. In SDS-PAGE, the lectin migrated as a single band of M(r) 31.6 kDa under reducing and nonreducing conditions, indicating that it is a tetramer of apparently identical subunits. It agglutinated red blood cells (RBCs) from rabbit and human ABO blood groups. It also reacted with RBCs from rat, sheep, goat and guinea pig but after desialylation with neuraminidase. The hemagglutination activity of the lectin was inhibited by D-galactose and its derivatives. Amino acid analysis showed that lectin was rich in aspartic and glutamic acid and, did not contain sulphur containing amino acids. The lectin is a glycoprotein having 1.41% of neutral sugars. It is labile at temperature above 60 degrees C. It needs divalent cations for its activity, as a loss of activity was observed on removal of Ca2+ and Mn2+. Denaturing agents like urea, thiourea and guanidine-HCl have no effect on its activity.     

Early steps in cold sensing by plant cells: the role of actin cytoskeleton and membrane fluidity

Many plants acquire freezing tolerance through cold acclimatization (CA), a prolonged exposure to low but non-freezing temperatures at the onset of winter. CA is associated with gene expression that requires transient calcium influx into the cytosol. Alfalfa (Medicago sativa) cells treated with agents blocking this influx are unable to cold-acclimatize. Conversely, chemical agents causing increased calcium influx induce cold acclimatization-specific (cas) gene expression in alfalfa at 25 degrees C. How low temperature triggers calcium influx is, however, unknown. We report here that induction of a CA-specific gene (cas30), calcium influx and freezing tolerance at 4 degrees C are all prevented by cell membrane fluidization, but, conversely, are induced at 25 degrees C by membrane rigidification. cas30 expression and calcium influx at 4 degrees C are also prevented by jasplakinolide (JK), an actin microfilament stabilizer, but induced at 25 degrees C by the actin microfilament destabilizer cytochalasin D (CD). JK blocked the membrane rigidifier-induced, but not the calcium channel agonist-induced cas30 expression at 25 degrees C. These findings indicate that cytoskeleton re-organization is an integral component in low-temperature signal transduction in alfalfa cell suspension cultures, serving as a link between membrane rigidification and calcium influx in CA.     

Local people value environmental services provided by forested parks

Garnering support from local people is critical for maintaining ecologically viable and functional protected areas. However, empirical data illustrating local people’s awareness of the importance of nature’s services is limited; hence possibly impeding effective ecosystem (environmental)-services based conservation efforts. Using data from five protected forests in four developing Southeast Asian countries, we provide evidence that local people living near parks value a wide range of environmental services, including cultural, provisioning, and regulating services, provided by the forests. Local people with longer residency valued environmental services more. Educated as well as poor people valued forest ecosystem services more. Conservation education has some influence on people’s environmental awareness. For conservation endeavors to be successful, large-scale transmigration programs should be avoided and local people must be provided with alternative sustenance opportunities and basic education in addition to environmental outreach to reduce their reliance on protected forests and to enhance conservation support.     

The state and conservation of Southeast Asian biodiversity

Southeast Asia is a region of conservation concern due to heavy losses of its native habitats. In this overview, we highlight the conservation importance of Southeast Asia by comparing its degree of species endemism and endangerment, and its rate of deforestation with other tropical regions (i.e., Meso-America, South America, and Sub-Saharan Africa). Southeast Asia contains the highest mean proportion of country-endemic bird (9%) and mammal species (11%). This region also has the highest proportion of threatened vascular plant, reptile, bird, and mammal species. Furthermore, not only is Southeast Asia’s annual deforestation rate the highest in the tropics, but it has also increased between the periods 1990–2000 and 2000–2005. This could result in projected losses of 13–85% of biodiversity in the region by 2100. Secondary habitat restoration, at least in certain countries, would allow for some amelioration of biodiversity loss and thus potentially lower the currently predicted extinction rates. Nonetheless, urgent conservation actions are needed. Conservation initiatives should include public education, sustaining livelihoods, and ways to enhance the sustainability of agriculture and increase the capacity of conservation institutions. Furthermore, these actions should be country-specific and not ignore areas heavily populated by humans, as they can also harbour high numbers of threatened species. We urge that cooperative conservation initiatives be undertaken and support (e.g., capacity-building) be given by more developed countries in the region and beyond.     

The metalloreductase Fre6p in Fe-efflux from the yeast vacuole

The yeast vacuole is the storage depot for cellular iron. In this report we quantify the import-export balance in the vacuole because of the import of iron by Ccc1p and to export by the combined activity of Smf3p and the ferroxidase, permease pair of proteins, Fet5p and Fth1p. Our data indicate that the two efflux pathways are equally efficient in trafficking iron out of the vacuole. A major focus of this work was to identify the ferrireductase(s) that supplies the Fe(II) for efflux whether by Smf3p or the Fet5p-Fth1p complex. Using a combination of flameless atomic absorption spectrophotometry to quantify vacuolar and whole cell iron content and a reporter assay for cytoplasmic iron we demonstrate that Fre6p supplies Fe(II) to both efflux systems, while Fre7p plays no role in Fe-efflux from the vacuole. Enzymatic assay shows the two fusions to have similar reductase activity, however. Confocal fluorescence microscopy demonstrates that Fre6:GFP localizes to the vacuolar membrane; in contrast, Fre7:GFP fusions exhibit a variable and diffuse cellular distribution. Demonstrating a role for a vacuolar metalloreductase in Fe-efflux supports the model that iron is stored in the vacuole in the ferric state.     

Unreported yet massive deforestation driving loss of endemic biodiversity in Indian Himalaya

Deforestation is a primary driver of biotic extinctions in the tropics. The impacts of deforestation in tropical biodiversity hotspots are of particular concern because these regions contain high concentrations of globally endemic species. However, the effects of large-scale deforestation on native biotas within the biodiversity hotspot of Himalaya remain poorly documented. Here we report on an alarming trend of deforestation in the Indian Himalaya and project the likely consequential extinctions of endemic taxa (species and subspecies) by 2100 across a broad range of taxonomic groups, including gymnosperms, angiosperms, fishes, amphibians, reptiles, birds, and mammals. With the current level of deforestation, by 2100 only about 10% of the land area of the Indian Himalaya will be covered by dense forest (>40% canopy cover)—a scenario in which almost a quarter of the endemic species could be wiped out, including 366 endemic vascular plant taxa and 35 endemic vertebrate taxa. We also show that inaccurate reporting of forest cover data by governmental institutions can result in underestimations of the biological impacts of deforestation, as well as potential miscalculations in land-use decisions (e.g., the construction of hydroelectric dams). Large-scale conservation efforts, including forest protection and reforestation, are urgently needed to avoid the impending deforestation-driven biodiversity losses in the Himalaya.     

Endemic predators, invasive prey and native diversity

Interactions between native diversity and invasive species can be more complex than is currently understood. Invasive ant species often substantially reduce diversity in the native ants diversity that act as natural control agents for pest insects. In Indonesia (on the island of Sulawesi), the third largest cacao producer worldwide, we show that a predatory endemic toad (Ingerophrynus celebensis) controls invasive ant (Anoplolepis gracilipes) abundance, and positively affects native ant diversity. We call this the invasive-naivety effect (an opposite of enemy release), whereby alien species may not harbour anti-predatory defences against a novel native predator. A positive effect of the toads on native ants may facilitate their predation on insect vectors of cacao diseases. Hence, toads may increase crop yield, but further research is needed on this aspect. Ironically, amphibians are globally the most threatened vertebrate class and are strongly impacted by the conversion of rainforest to cacao plantations in Sulawesi. It is, therefore, crucial to manage cacao plantations to maintain these endemic toads, as they may provide critical ecosystem services, such as invasion resistance and preservation of native insect diversity.     

Global macroecology of bird assemblages in urbanized and semi‐natural ecosystems

Aim Despite the increasing pace of urbanization, little is known about how this process affects biodiversity globally. We investigate macroecological patterns of bird assemblages in urbanized areas relative to semi‐natural ecosystems. Location World‐wide. Methods We use a database of quantitative bird surveys to compare key assemblage structure parameters for plots in urbanized and semi‐natural ecosystems controlling for spatial autocorrelation and survey methodology. We use the term ‘urbanized’ instead of ‘urban’ ecosystems as many of the plots were not located in the centre of towns but in remnant habitat patches within conurbations. Results Some macroecological relationships were conserved in urbanized landscapes. Species–area, species–abundance and species–biomass relationships did not differ significantly between urbanized and non‐urbanized environments. However, there were differences in the relationships between productivity and assemblage structure. In forests, species richness increased with productivity; in both forests and open habitats, the evenness of species abundances declined as productivity increased. Among urbanized plots, instead, both species richness and the evenness of species abundances were independent of variation in productivity. Main conclusions Remnant habitats within urbanized areas are subject to many ecological alterations, yet key macroecological patterns differ remarkably little in urbanized versus non‐urbanized plots. Our results support the need for increased conservation activities in urbanized landscapes, particularly given the additional benefits of local experiences of biodiversity for the human population. With increasing urbanization world‐wide, broad‐scale efforts are needed to understand and manage the effects of this driver of change on biodiversity.     

Area 5 influences excitability within the primary motor cortex in humans

In non-human primates, Brodmann's area 5 (BA 5) has direct connectivity with primary motor cortex (M1), is largely dedicated to the representation of the hand and may have evolved with the ability to perform skilled hand movement. Less is known about human BA 5 and its interaction with M1 neural circuits related to hand control. The present study examines the influence of BA 5 on excitatory and inhibitory neural circuitry within M1 bilaterally before and after continuous (cTBS), intermittent (iTBS), and sham theta-burst stimulation (sham TBS) over left hemisphere BA 5. Using single and paired-pulse TMS, measurements of motor evoked potentials (MEPs), short interval intracortical inhibition (SICI), and intracortical facilitation (ICF) were quantified for the representation of the first dorsal interosseous muscle. Results indicate that cTBS over BA 5 influences M1 excitability such that MEP amplitudes are increased bilaterally for up to one hour. ITBS over BA 5 results in an increase in MEP amplitude contralateral to stimulation with a delayed onset that persists up to one hour. SICI and ICF were unaltered following TBS over BA 5. Similarly, F-wave amplitude and latency were unaltered following cTBS over BA 5. The data suggest that BA 5 alters M1 output directed to the hand by influencing corticospinal neurons and not interneurons that mediate SICI or ICF circuitry. Targeting BA 5 via cTBS and iTBS is a novel mechanism to powerfully modulate activity within M1 and may provide an avenue for investigating hand control in healthy populations and modifying impaired hand function in clinical populations.