Effect of climate change on mast-seeding species: frequency of mass flowering and escape from specialist insect seed predators

Global surface temperatures are expected to increase by several degrees in the next century, with potentially large but poorly understood impacts on ecological interactions. Here we propose potential effects of increased temperatures on ecologically dominant New Zealand grasses (Chionochloa spp.) that mass flower and mast seed. Twenty-two years’ data from five masting Chionochloa species in New Zealand showed that the cue for heavy flowering was unusually high temperature in the summer of the year before flowering. Attack by predispersal insect seed predators was much reduced in mast years, apparently because predator populations were satiated. Increased temperatures would greatly decrease interannual variation in Chionochloa flowering, allowing seed predator populations to increase and potentially to devastate the seed crop annually. Similar responses are likely in masting species worldwide. This previously unrecognized effect of global warming could have widespread impacts on temperate ecosystems.     

A clinally varying promoter polymorphism associated with adaptive variation in wing size in Drosophila

Body size often shows adaptive clines in many ectotherms across altitude and latitude, but little is known about the genetic basis of these adaptive clines. Here we identify a polymorphism in the Dca (Drosophila cold acclimation) gene in Drosophila melanogaster that influences wing size, affects wing:thorax allometry and also controls a substantial proportion of the clinal wing‐size variation. A polymorphism in the promoter region of Dca had two common alleles showing strong reciprocal clinal variation in frequency with latitude along the east coast of Australia. The Dca‐237 allele increased towards the tropics where wing size is smaller. A within‐population association study highlighted that an increase in the frequency of this allele decreased wing size but did not influence thorax size. A manipulated increase in the level of expression of Dca achieved through UAS‐GAL4 was associated with a decrease in wing size but had no effect on thorax size. This was consistent with higher Dca expression levels in family lines with higher frequency of the Dca‐237 allele. Genetic variation in the promoter region of the Dca gene appears to influence adaptive size variation in the eastern Australian cline of Drosophila melanogaster and accounts for more than 10% of the genetic variation in size within and between populations.     

The Correlation of Digestive Vacuole pH and Size with the Digestive Cycle in Paramecium caudatum1

ABSTRACT. The temporal changes in the size and pH of digestive vacuoles (DV) in Paramecium caudatum were reevaluated. Cells were pulsed briefly with polystyrene latex spheres or heat-killed yeast stained with three sulfonphthalein indicator dyes. Within 5 min of formation the intravacuolar pH declined from ～7 to 3. With the exception of a transient and early increase in vacuolar size, vacuole condensation occurred rapidly and paralleled the acidification so that vacuoles reached their lowest pH and minimal size simultaneously. Neutralization and expansion of vacuole size began when vacuoles were GT8 min old. No labeled vacuoles were defecated prior to 21 min after formation but almost all DV were defecated within 1 h so that the digestive cycle of individual vacuoles ranged from 21 to 60 min. Based on these size and pH changes, the presence of acid phosphatase activity, and membrane morphology, digestive vacuoles can be grouped into four stages of digestion. The DV-I are GT6 min old and undergo rapid condensation and acidification. The DV-II are between 4 to 10 min old and are the most condensed and acidic vacuoles. The DV-III range in age from 8 to ～20 min and include the expanding or expanded vacuoles that result from lysosomes fusing with DV-II. The DV-IV are GD21 min old, and since digestion is presumably completed, they can be defecated. The rise in intravacuolar pH that accompanies vacuole expansion suggests that lysosomes play a role in vacuole neutralization in addition to their degradative functions. The acidification and condensation processes in DV-I appear to be unrelated to lysosomal function, as no acid phosphaiase activity has been detected at this stage, but may be related to phagosomal functions important in killing food organisms, denaturing proteins prior to digestion, and preparing vacuole membrane for fusion with lysosomes.     

Response of instream animal communities to a short-term extreme event and to longer-term cumulative impacts in a strategic water resource area,South Africa

Disturbance plays an integral part in generating heterogeneity required for ecosystem persistence, but the increased amplitude and duration of disturbances linked to drivers of global change could result in ecosystem shifts or collapse. Biomonitoring over time provides insights into trajectories of ecosystem change. The responses of two instream animal taxa to two contrasting disturbance events, a major flood event and the long-term cumulative effects of land-use changes, were assessed in 1999–2012 by quantifying variation and change in abundance of functional groups based on flow rate sensitivity, water quality and metrics of ecological condition. All metrics recovered to pre-flood conditions within seven months after the flood event. Similarly, cumulative impacts of land use effected significant decreases in some but not all metrics. Indices that did not change, including SASS total score and ASPT, were the result of insufficient consideration of the decrease in the abundance of sensitive taxa specifically, and the abundance of all taxa in general. The decrease in abundance of sensitive taxa could signal imminent collapse in certain metrics. Evidence is also provided for a shift in the structure of fish assemblages linked to the decrease and loss of taxa sensitive to ecosystem degradation caused by the longer-term impacts of land-use change.     

Effects of optimum doses of nitrogen,phosphorus, potassium and calcium on silkworm,Bombyx mori L., growth and yield

Silkworm rearing has been an income source for small-holding farmers in Pakistan. Over the years efforts have been made to improve silkworm quality and quantity and thus develop better prospects for increasing yield and income. Mulberry leaves Morus alba L. in a series of experiments have been supplemented with various nutrients in different doses and combinations. Relative success has been achieved in this context. In our present experiments on silkworm Bombyx mori L., we fed the larvae on mulberry leaves supplemented with different doses of N (0.2%), P (0.1%), K (0.3%) and Ca (0.1%) at 26 ± 3°C with 65 ± 5% relative humidity. The results showed better outputs in terms of food consumption (72.55 g/10 larvae), coefficient of utilization (76.45%), body weight (70.07 g/10 larvae) and body length (8.56 cm/larvae) than where simple mulberry leaves were offered. Our net gains with these production parameters have been in terms of heavier cocoons with and without pupa (2.25 and 0.69 g/cocoon), respectively.     

Black light trap collections in Wangging county and Yanji city,Jilin Province,China, August 2006–2007

Adult mosquito surveillance was conducted using black light traps in August of 2006 and 2007 at Wangging county and Yanji city, Jilin Province, China to identify the distribution of anopheline mosquitoes in northern China. A total of 2459 female mosquitoes comprising three genera and eight species including Anopheles (Anopheles) lesteri, An. (Ano.) kleini, An. (Ano.) pullus, Culex inatomii, Cx. orientalis, Cx. pipiens, Cx. bitaeniorhynchus and Aedes vexans nipponii were collected. The most commonly collected species was An. kleini which had not been previously reported from China. Anopheles sinensis sensu stricto is commonly collected throughout China, but was not collected from these areas.     

Characterization of polymorphic tetranucleotide microsatellite loci from the Siberian weasel (Mustela sibirica)

Nine tetrarepeat microsatellite loci for Siberian weasel (Mustela sibirica) were characterized. By using 35 individuals of unknown relationship collected from Taiwan, we evaluated the polymorphism of these loci. The number of alleles for each locus ranged from five to 12 (mean = 8.78 alleles) and the observed heterozygosity from 0.429 to 0.962 (mean = 0.688) and all loci conformed to Hardy–Weinberg expectation.     

Development of compound microsatellite markers in the harmful dinoflagellate Cochlodinium polykrikoides (Dinophyceae)

We isolated 15 polymorphic microsatellites from Cochlodinium polykrikoides. These loci provide a class of highly variable genetic markers, as the number of alleles ranged from two to 15, and the estimate of gene diversity was from 0.083 to 0.880 across the 15 microsatellites. We consider that these loci have a potential to reveal the genetic structure and gene flow among C. polykrikoides populations.     

Production, recovery and immunogenicity of the protective antigen from a recombinant strain of Bacillus anthracis

The protective antigen (PA) is one of the three components of the anthrax toxin. It is a secreted nontoxic protein with a molecular weight of 83 kDa and is the major component of the currently licensed human vaccine for anthrax. Due to limitations found in the existing vaccine formulation, it has been proposed that genetically modified PA may be more effective as a vaccine. The expression and the stability of two recombinant PA (rPA) variants, PA-SNKE-ΔFF-E308D and PA-N657A, were studied. These proteins were expressed in the nonsporogenic avirulent strain BH445. Initial results indicated that PA-SNKE-ΔFF-E308D, which lacks two proteolysis-sensitive sites, is more stable than PA-N657A. Process development was conducted to establish an efficient production and purification process for PA-SNKE-ΔFF-E308D. pH, media composition, growth strategy and protease inhibitors composition were analyzed. The production process chosen was based on batch growth of B. anthracis using tryptone and yeast extract as the only source of carbon, pH control at 7.5, and antifoam 289. Optimal harvest time was 14–18 h after inoculation, and EDTA (5 mM) was added upon harvest for proteolysis control. Recovery of the rPA was performed by expanded-bed adsorption (EBA) on a hydrophobic interaction chromatography (HIC) resin, eliminating the need for centrifugation, microfiltration and diafiltration. The EBA step was followed by ion exchange and gel filtration. rPA yields before and after purification were 130 and 90 mg/l, respectively. The purified rPA, without further treatment, treated with small amounts of formalin or adsorbed on alum, induced, high levels of IgG anti-PA with neutralization activities. Journal of Industrial Microbiology & Biotechnology (2002) 28, 232–238 DOI: 10.1038/sj/jim/7000239 Received 28 August 2001/ Accepted in revised form 20 December 2001     

Patterns of protein synthesis and accumulation during oogenesis in the polychaete,Pseudopotamilla occelata Moore

Summary

Proteins synthesized and accumulated during oogenesis or Pseudopotamilla occelata were analyzed by two-dimensional Polyacrylamide gel electrophoresis and fluorography. Significant changes in the patterns of synthesis and accumulation occur during oogenesis, paticularly between previtellogenic and vitellogenic stages, although many of the proteins are represented throughout the process. The changes may be generally dependent upon the variation in the gene expression affecting autosynthesis of proteins. However, appearance of proteins, which occur only at the vitellogenic stages but apparently not synthesized within the oocytes, indicates that heterosynthetic proteins are stage-specifically transported into oocytes.