The Drosophila VEGF receptor homolog is expressed in hemocytes.

Several signalling pathways have been defined by studies of genes originally characterised in Drosophila. However, some mammalian signalling systems have so far escaped discovery in the fly. Here, we describe the identification and characterisation of fly homologs for the mammalian vascular endothelial growth factor/platelet derived growth factor (VEGF/PDGF) and the VEGF receptor. The Drosophila factor (DmVEGF-1) gene has two splice variants and is expressed during all stages, the signal distribution during embryogenesis being ubiquitous. The receptor (DmVEGFR) gene has several splice variants; the variations affecting only the extracellular domain. The most prominent form is expressed in cells of the embryonic haematopoietic cell lineage, starting in the mesodermal area of the head around stage 10 of embryogenesis. Expression persists in hemocytes as embryonic development proceeds and the cells migrate posteriorly. In a fly strain carrying a deletion uncovering the DmVEGFR gene, hemocytes are still present, but their migration is hampered and the hemocytes remain mainly in the anterior end close to their origin. These data suggest that the VEGF/PDGF signalling system may regulate the migration of the Drosophila embryonic haemocyte precursor cells.     

Protein metabolism and strength performance after bovine colostrum supplementation

Summary. This study was designed to determine the responses of muscle protein, serum amino acids, and strength performance to bovine colostrum supplementation in physically active men. The rest (R) group (n=6) and the exercise (E) group (n=6) carried out twice a 2-week experiment randomly assigned in a double-blind fashion with either placebo (PLA; consuming daily 20g maltodextrin) or bovine colostrum (COL; consuming daily 20g colostrum supplement) treatment with one month between. On the test day after the treatment period the measurements were carried out in fasting conditions and E carried out a strength training session (STS). The methods involved the infusion of ring-²H₅-phenylalanine, femoral arterial and venous blood sampling, and biopsies from the vastus lateralis muscle. Serum concentration of essential amino acids during recovery was greater (p<0.05) in the COL groups compared with the PLA groups. Both muscle protein synthesis and breakdown increased (p<0.05) with COL. There were no differences in phenylalanine net balance or strength performance between the PLA and COL groups. It was concluded that a 2-week supplementation with bovine colostrum in physically active men increases serum concentration of essential amino acids but has no effect either on strength performance or protein net balance in fasting conditions during recovery after STS.     

Afforestation does not necessarily reduce nitrous oxide emissions from managed boreal peat soils

Pristine peatlands have generally low nitrous oxide (N₂O) emissions but drainage and management practices enhance the microbial processes and associated N₂O emissions. It is assumed that leaving peat soils from intensive management, such as agriculture, will decrease their N₂O emissions. In this paper we report how the annual N₂O emission rates will change when agricultural peat soil is either left abandoned or afforested and also N₂O emissions from afforested peat extraction sites. In addition, we evaluated a biogeochemical model (DNDC) with a view to explaining GHG emissions from peat soils under different land uses. The abandoned agricultural peat soils had lower mean annual N₂O emissions (5.5?±?5.4?kg?N?ha^?1) than the peat soils in active agricultural use in Finland. Surprisingly, N₂O emissions from afforested organic agricultural soils (12.8?±?9.4?kg?N?ha^?1) were similar to those from organic agricultural soils in active use. These emissions were much higher than those from the forests on nutrient rich peat soils. Abandoned and afforested peat extraction sites emitted more N₂O, (2.4?±?2.1?kg?N?ha^?1), than the areas under active peat extraction (0.7?±?0.5?kg?N?ha^?1). Emissions outside the growing season contributed significantly, 40% on an average, to the annual emissions. The DNDC model overestimated N₂O emission rates during the growing season and indicated no emissions during winter. The differences in the N₂O emission rates were not associated with the age of the land use change, vegetation characteristics, peat depth or peat bulk density. The highest N₂O emissions occurred when the soil C:N ratio was below 20 with a significant variability within the measured C:N range (13–27). Low soil pH, high nitrate availability and water table depth (50–70?cm) were also associated with high N₂O emissions. Mineral soil has been added to most of the soils studied here to improve the fertility and this may have an impact on the N₂O emissions. We infer from the multi-site dataset presented in this paper that afforestation is not necessarily an efficient way to reduce N₂O emissions from drained boreal organic fields.     

Carbon fluxes from a tropical peat swamp forest floor

A tropical ombrotrophic peatland ecosystem is one of the largest terrestrial carbon stores. Flux rates of carbon dioxide (CO₂) and methane (CH₄) were studied at various peat water table depths in a mixed‐type peat swamp forest floor in Central Kalimantan, Indonesia. Temporary gas fluxes on microtopographically differing hummock and hollow peat surfaces were combined with peat water table data to produce annual cumulative flux estimates. Hummocks formed mainly from living and dead tree roots and decaying debris maintained a relatively steady CO₂ emission rate regardless of the water table position in peat. In nearly vegetation‐free hollows, CO₂ emission rates were progressively smaller as the water table rose towards the peat surface. Methane emissions from the peat surface remained small and were detected only in water‐saturated peat. By applying long‐term peat water table data, annual gas emissions from the peat swamp forest floor were estimated to be 3493±316 g CO₂ m^?2 and less than 1.36±0.57 g CH₄ m^?2. On the basis of the carbon emitted, CO₂ is clearly a more important greenhouse gas than CH₄. CO₂ emissions from peat are the highest during the dry season, when the oxic peat layer is at its thickest because of water table lowering.     

Expression of Rhizobium galegae common nod clones in various backgrounds.

The cosmid clone pRg30, carrying common nodulation genes of Rhizobium galegae HAMBI 1174, and pRg33, a subclone of pRg30 that contains a 5.7-kb ClaI insert carrying nodDABC were conjugated into various Rhizobium nod- mutant strains and into a Ti plasmid-cured Agrobacterium tumefaciens. Complementation and expression of the nodABC genes of R. galegae were studied by following microscopically the infection process and the nodulation on different test plants. The nodABC genes of R. galegae complemented the nod- strains of other Rhizobium species. The presence of extra copies of common nod genes in the homologous R. galegae nodABC- strain induced an increased nodulation on Galega orientalis. However, the inserts of R. galegae in pRg30 and pRg33 do not carry sufficient genetic information for normal nodulation of test plants in an Agrobacterium background, because the Agrobacterium transconjugants induced root hair deformation on Galega plants, but no infection threads were detected and nodulelike structures developed only at low frequency. The Agrobacterium carrying the nodDABC of R. galegae did not cause the root hairs of Medigo sativa to deform.     

Melanoma cell-derived factors stimulate hyaluronan synthesis in dermal fibroblasts by upregulating HAS2 through PDGFR-PI3K-AKT and p38 signaling

In many cancers hyaluronan content is increased, either by tumor cells or the surrounding stromal cells and this increased hyaluronan content correlates with unfavorable clinical prognosis. In the present work, we studied the effects of melanoma cell (aggressive melanoma cell line C8161)-derived factors on fibroblast hyaluronan synthesis, intracellular signaling, MMP expression and invasion. Treatment of the fibroblast cultures with melanoma cell conditioned medium (CM) caused accumulation of hyaluronan in the culture medium and formation of thick pericellular hyaluronan coat and hyaluronan cables. The expression of Has2 was increased approximately 20-fold by the C8161 melanoma cell CM, while Has1 and Has3 were increased twofold. Knock-down of Has2 expression with siRNA showed that Has2 was responsible for the increased hyaluronan synthesis induced by the melanoma cell CM. To find out the signaling routes, which led to Has2 upregulation, the phosphorylation profiles of 46 kinases were screened with phosphokinase array kit. Melanoma cell CM treatment strongly induced a rapid phosphorylation of p38, JNK, AKT, CREB, HSP27, STAT3 and cJUN. Treatment of the fibroblasts with specific inhibitors of PI3K, AKT and p38 reduced the melanoma cell CM-induced hyaluronan secretion, while the inhibitor of PDGFR totally blocked it. In addition, siRNA for PDGFRα/β inhibited Has2 upregulation in melanoma cell CM-treated fibroblasts. In parallel with the increased hyaluronan synthesis the melanoma cell CM-treated fibroblasts showed spindle shape, numerous long cell protrusions, enhanced MMP expression and increased invasion into collagen-Cultrex matrix. siRNA blocking of Has2 or PDGFRα/β expression reversed the stimulatory effect of melanoma cell CM on fibroblast invasion. PDGF secreted by melanoma cells thus mediated fibroblasts activation, with HAS2 upregulation as a major factor in the fibroblast response. This effect on stromal matrix is suggested to favor tumor growth.     

Fish–duck interactions in boreal lakes in Finland as reflected by abundance correlations

We studied the hypothesis that fish play an important role in lake use by ducks (pairs and broods) in boreal lakes. The study was based on densities of different duck and fish species in 28 boreal lakes in southern Finland. We focused on the three most common duck species (mallard Anas platyrhynchos, green-winged teal A. crecca and common goldeneye Bucephala clangula) and on the three most common fish species (perch Perca fluviatilis, roach Rutilus rutilus and pike Esox lucius) in the region. We considered both competitive and predatory interactions between ducks and fish, the perch and roach being potential competitors with ducks and the pike a potential predator of ducks. We found a negative association between green-winged teal brood density and total fish density, the other duck species having only a weak association with total fish density. When the three fish species were considered separately, a negative association, suggesting food competition, was found between perch, green-winged teal and goldeneye, whereas the role of roach as a food competitor seemed to be of minor importance. We did not find any clear signs of predatory effects of pike on ducks. Our results suggest that food competition is a more important factor than pike predation in affecting lake use by ducks in oligotrophic boreal environments in southern Finland.     

Dual signalling by different octopamine receptors converges on adenylate cyclase in Sf9 cells.

The Sf9 insect cell line, derived from Spodoptera frugiperda, was used to study the regulation of adenylate cyclase (AC) activity by octopamine receptors. The cyclic AMP (cAMP) production was stimulated in a concentration-dependent manner by octopamine. Octopamine also elicited a rise in cytosolic Ca(2+). The Ca(2+) elevation was independent of the cAMP elevation whereas the cAMP elevation was partially inhibited by removal of Ca(2+). The antagonistic effects of a series of compounds were tested on both responses. Phentolamine inhibited both responses with similar potency. Two of the tested compounds, MK-912 and RS 79948, were over 1000-fold more potent in blocking the Ca(2+) response. Ionomycin, a Ca(2+) ionophore, or activation of the heterologously expressed muscarinic M(3) receptors in the cells did not alone stimulate cAMP production. However, a Ca(2+) elevation potentiated cAMP production in the presence of a primary stimulant such as forskolin or activated G(s) proteins. This type of regulation of AC is different from previously identified Ca(2+)-sensitive AC isoforms. For comparison the Ca(2+)/calmodulin-activated type I AC was expressed and demonstrated to be stimulated directly by an increase in Ca(2+). Together the results demonstrate that octopamine can synergistically regulate the AC activity via two different receptors in Sf9 cells.     

Infant Growth after Preterm Birth and Mental Health in Young Adulthood

Objectives

Faster growth after preterm birth benefits long-term cognitive functioning. Whether these benefits extend to mental health remains largely unknown. We examined if faster growth in infancy is associated with better self-reported mental health in young adults born preterm at very low birth weight (VLBW) (<1500g).

Study Design

As young adults, participants of the Helsinki Study of Very Low Birth Weight Adults self-reported symptoms of depression and attention deficit/hyperactivity disorder (ADHD) (n = 157) and other psychiatric problems (n = 104). As main predictors of mental health outcomes in linear regression models, we used infant weight, length, and head circumference at birth, term, and 12 months of corrected age, and growth between these time points. Growth data were collected from records and measures at term and at 12 months of corrected age were interpolated. Additionally, we examined the moderating effects of intrauterine growth restriction.

Results

Size at birth, term, or 12 months of corrected age, or growth between these time points were not associated with mental health outcomes (p-values >0.05). Intrauterine growth restriction did not systematically moderate any associations.

Conclusions

Despite the high variability in early growth of VLBW infants, the previously described association between slow growth in infancy and poorer cognitive functioning in later life is not reflected in symptoms of depression, ADHD, and other psychiatric problems. This suggests that the development of cognitive and psychiatric problems may have dissimilar critical periods in VLBW infants.