Modelling the interplay between pest movement and the physical design of trap crop systems

Abstract 1 The interplay between pest movement and trap crop physical design is modelled in a situation where the pest moves by a random walk with spatially variable mobility. Questions addressed are: (i) how does the proportion of trap crop area of the total field area influence the equilibrium distribution of pests among the crop and the trap crop and (ii) how do crop patch size and shape influence the speed of pest redistribution from the crop to the trap crop. 2 When pest mobility in the trap crop is clearly lower than that in the crop, the pest population in the crop decreases very sharply for small trap crop proportions. When mobility in the trap crop is slightly closer to that in the crop, the pest population in the crop decreases much more gradually with increasing trap crop proportion. Thus finding a trap crop that the pest distinctly prefers over the crop appears to be crucial for developing efficient trap crop systems. 3 The rate of decay in the pest population in the crop increases with increasing perimeter to area ratio of the crop patch. Hence, designing field layouts to increase the perimeter to area ratio of crop patches may be beneficial.     

Piracetam Prevents Scopolamine-Induced Memory Impairment and Decrease of NTPDase, 5′-Nucleotidase and Adenosine Deaminase Activities

Piracetam improves cognitive function in animals and in human beings, but its mechanism of action is still not completely known. In the present study, we investigated whether enzymes involved in extracellular adenine nucleotide metabolism, adenosine triphosphate diphosphohydrolase (NTPDase), 5′-nucleotidase and adenosine deaminase (ADA) are affected by piracetam in the hippocampus and cerebral cortex of animals subjected to scopolamine-induced memory impairment. Piracetam (0.02 μmol/5 μL, intracerebroventricular, 60 min pre-training) prevented memory impairment induced by scopolamine (1 mg/kg, intraperitoneal, immediately post-training) in the inhibitory avoidance learning and in the object recognition task. Scopolamine reduced the activity of NTPDase in hippocampus (53 % for ATP and 53 % for ADP hydrolysis) and cerebral cortex (28 % for ATP hydrolysis). Scopolamine also decreased the activity of 5′-nucleotidase (43 %) and ADA (91 %) in hippocampus. The same effect was observed in the cerebral cortex for 5′-nucleotidase (38 %) and ADA (68 %) activities. Piracetam fully prevented scopolamine-induced memory impairment and decrease of NTPDase, 5′-nucleotidase and adenosine deaminase activities in synaptosomes from cerebral cortex and hippocampus. In vitro experiments show that piracetam and scopolamine did not alter enzymatic activity in cerebral cortex synaptosomes. Moreover, piracetam prevented scopolamine-induced increase of TBARS levels in hippocampus and cerebral cortex. These results suggest that piracetam-induced improvement of memory is associated with protection against oxidative stress and maintenance of NTPDase, 5′-nucleotidase and ADA activities, and suggest the purinergic system as a putative target of piracetam.     

The impact of simulated moose densities on conifer aphids along a productivity gradient

Large herbivores have a significant impact on boreal forest ecosystems. The modification of resources through their feeding induces changes in trophic dynamics and affects the direction of interactions in a community. Moose Alces alces may decrease the available plant biomass for herbivorous insects on one of their main winter forage species in Fennoscandia, Scots pine Pinus sylvestris, and indirectly alter the abundance of invertebrates through exploitative competition. Moose browsing can also induce chemical, morphological, and phenological changes in plants, changing their nutritive value to insect herbivores such as aphids. Habitat productivity may further modify the responses of aphids to moose browsing. We studied the responses of the gray pine aphid Schizolachnus pineti to different moose densities, and their relations to habitat productivity by sampling pine branches and measuring the number of aphids on pine needles. The experimental setup consisted of 8 exclosures along a productivity gradient, where the feeding, defecation, and urination of 4 densities of moose had been simulated for 7 yr. We here show that high levels of simulated browsing decrease the amount of gray pine aphids in areas with high productivity. In areas with low productivity, however, simulated browsing had no such effect. Habitat productivity should therefore be considered as an important factor that may determine the strength of an areas buffering capacity to high moose densities. Low resource environments appear to be favourable to specialist conifer aphids on pines under high browsing pressure, but the performance of generalist insect herbivores might be lowered.     

A barley (Hordeum vulgare L.) LEA3 protein, HVA1, is abundant in protein storage vacuoles

The HVA1 protein belongs to the LEA3 group, which is expressed during the late stage of seed maturation. It is also induced by exogenous abscisic acid (ABA) and a variety of environmental stresses in germinating barley (Hordeum vulgare L.). In the present work, the potential role of HVA1 was investigated by studying its tissue distribution and subcellular localization in mature and stressed seeds by immuno-microscopic methods. In the mature seed, HVA1 protein was detected in all tissues except the non-living starchy endosperm. During germination the amount of HVA1 protein decreased but did not totally disappear. Incubation with 100 μM ABA, cold treatment or drought stress dramatically increased HVA1 expression in the germinated seed. In this work, the distribution of a LEA3 group protein was studied in a cereal seed for the first time by immuno-electron microscopy. In the scutellum and aleurone layer, HVA1 was localized both in the cytoplasm and protein storage vacuoles (PSVs). HVA1 protein was found to be threefold more abundant in PSVs than in the cytoplasm of an unstressed seed tissue. The ratio increased with ABA or stress treatments to at least ninefold. The role of HVA1 in PSVs remains unclear: a previously suggested possibility is ion sequestration to prevent precipitation during stress. On the other hand, HVA1 protein could also be degraded in PSVs. HVA1 protein does not have the signal peptide typical of proteins which are glycosylated and targeted into the vacuole via the Golgi complex. Because HVA1 is not glycosylated, it may use an alternative, ER-independent vacuolar pathway, also found in yeast cells.     

Impact of stromal cell composition on BMP-induced chondrogenic differentiation of mouse bone marrow derived mesenchymal cells

Chondrogenic differentiation in mesenchymal stromal cells (MSCs) has been actively studied due to their potential use in mesenchymal tissue repair. Our goal was to develop a simple isolation protocol for adherent mouse MSCs to simultaneously clear off hematopoietic cells and expand to obtain enough starting material for differentiation studies. CD34 and CD45 expressing cells were rapidly removed by inhibiting growth of hematopoietic cells to yield short-term selected (STS) cells. Further passaging enriched more primitive, uniformly Sca-1 expressing, long-term selected (LTS) cells. The efficacy of several BMPs to induce chondrogenesis in pellet culture was compared in STS and LTS cells. In STS cells, chondrogenesis progressed rapidly to terminal differentiation while LTS cells differentiated at a slower rate with no hypertrophy. In LTS cells, rhBMP homodimers -2, -4, -6 and rhBMP2/7 heterodimer were effective enhancers of chondrogenesis over that of rhBMP-5 and -7. In STS cells, rhBMP-2 and rhBMP-7 supported rapid chondrogenesis and terminal differentiation over that of rhBMP-6. These data indicate the impact of stromal cell composition on the chondrogenic differentiation profile, which is an important aspect to be considered when standardizing differentiation assay conditions as well as developing MSC based cartilage repair technologies.     

Carnivore-livestock conflicts: determinants of wolf (Canis lupus) depredation on sheep farms in Finland

Wolves (Canis lupus) have recently expanded their distribution range into western and southern Finland, which has not hosted breeding wolves for over 100 years. This has raised concerns and public debate over wolf-livestock conflicts. Between 1998 and 2004 there were 45 wolf attacks on sheep on 34 farms. To assess the risk wolves may pose to sheep husbandry, we used data on depredation, sheep management, landscape structure and moose and wolf populations from continental Finland outside the area of reindeer husbandry to build models of the factors that may predispose sheep farms to wolf depredation. Our results provided evidence that sheep farms with the highest risk of wolf depredation were those located in regions where wolves were abundant. These farms were usually located close to the Russian border where the landscape is a mosaic of forest, wetlands and clear cut areas. These regions are sparsely populated by humans and farms are located far from each other. Finally, we generated probability maps based on generalised additive modelling to predict the risk of wolf predation on livestock in farms of southern Finland.     

Pathways affected by asbestos exposure in normal and tumour tissue of lung cancer patients

Background:

The early detection of prostate cancer has resulted in an increase in the number of patients with localized prostate cancer and has paralleled the reported reduction in prostate cancer mortality. The increased rate of detection of patients with localized prostate cancer may also increase the risk of potentially morbid therapy in a patient with indolent cancer. Defining the biomarker correlates of prostate cancer virulence will facilitate the appropriate application and development of therapy for patients with early disease.

Methods:

A 255 core prostate cancer tissue microarray (TMA) from 47 prostatectomy specimens with organ confined tumor was constructed. Prostate cancer foci of transition and peripheral zone origin were represented on the TMA. Further, replicate cores of the two Gleason grades comprising the Gleason score, representative of Gleason scores 5-9, were arrayed from each prostatectomy specimen. Standard immunohistochemical techniques were used to assess expression of nine, cell death and cell cycle regulatory proteins implicated in the pathogenesis of prostate cancer (bax, bcl-2, bcl-x_L, bin1, CD95, mdm2, p21, p53, and NFkB).

Results:

The Spearman correlation coefficient revealed a strong correlation of bax, bin1, FAS, p65 and p21 expression with Gleason grade. Spearman correlation coefficients showed that expression of, bax and bin1, bax and MDM2, Bax and p21, and bax and p65 NFkB was highly associated. Other significant associations were identified between bin1 and p21, bin1 and MDM2, bin1 and p65 NFkB and between p21 and p65 NFκB. A model for predicting the biological potential of Gleason score 7 prostate cancer using multivariable logistic regression methods was developed. The findings also indicate that the profile of specific markers for Gleason grade 3 prostate cancer correlates with the overall context of the Gleason score.

Conclusion:

These data support the view that important molecular differences exist among and between the Gleason scores. Furthermore, there is significant molecular heterogeneity among prostatectomy specimens containing Gleason grade 3 cancer. This observation may have broader implications regarding the determination of risk among patients with prostate cancer that is currently considered to be of either good prognosis or unclear prognosis, i.e. Gleason score 7 tumors.     

The driving force behind genomic diversity

Eukaryote genomes contain excessively introns, intergenic and other non-genic sequences that appear to have no vital functional role or phenotype manifestation. Their existence, a long-standing puzzle, is viewed from the principle of increasing entropy. According to thermodynamics of open systems, genomes evolve toward diversity by various mechanisms that increase, decrease and distribute genomic material in response to thermodynamic driving forces. Evolution results in an excessive genome, a high-entropy ecosystem of its own, where copious non-coding segments associate with low-level functions and conserved sequences code coordinated activities. The rate of entropy increase, equivalent to the rate of free energy decrease, is identified with the universal fitness criterion of natural selection that governs populations of genomic entities as well as other species.