The Effect of Wind and a Reduced Supply of Water on the Growth and Water Relations of Festuca arundinacea Schreb

Festuca arundinacea was grown at high and low wind-speeds attwo levels of soil water. Transpiration was increased at highwind-speed and accompanied by leaf water stress. Growth of leafarea was progressively reduced according to the severity ofthe experimental treatments in the sequence: wet soil and lowwind; dry soil and low wind; wet soil and high wind; dry soiland high wind. The leaf water potential was also reduced inthis sequence. Festuca arundinacea Schreb., transpiration, water stress, wind, water potential     

Leptin activation of mTOR pathway in intestinal epithelial cell triggers lipid droplet formation,cytokine production and increased cell proliferation

Accumulating evidence suggests that obesity and enhanced inflammatory reactions are predisposing conditions for developing colon cancer. Obesity is associated with high levels of circulating leptin. Leptin is an adipocytokine that is secreted by adipose tissue and modulates immune response and inflammation. Lipid droplets (LD) are organelles involved in lipid metabolism and production of inflammatory mediators, and increased numbers of LD were observed in human colon cancer. Leptin induces the formation of LD in macrophages in a PI3K/mTOR pathway-dependent manner. Moreover, the mTOR is a serine/threonine kinase that plays a key role in cellular growth and is frequently altered in tumors. We therefore investigated the role of leptin in the modulation of mTOR pathway and regulation of lipid metabolism and inflammatory phenotype in intestinal epithelial cells (IEC-6 cells). We show that leptin promotes a dose- and time-dependent enhancement of LD formation. The biogenesis of LD was accompanied by enhanced CXCL1/CINC-1, CCL2/MCP-1 and TGF-β production and increased COX-2 expression in these cells. We demonstrated that leptin-induced increased phosphorylation of STAT3 and AKT and a dose and time-dependent mTORC activation with enhanced phosphorilation of the downstream protein P70S6K protein. Pre-treatment with rapamycin significantly inhibited leptin effects in LD formation, COX-2 and TGF-β production in IEC-6 cells. Moreover, leptin was able to stimulate the proliferation of epithelial cells on a mTOR-dependent manner. We conclude that leptin regulates lipid metabolism, cytokine production and proliferation of intestinal cells through a mechanism largely dependent on activation of the mTOR pathway, thus suggesting that leptin-induced mTOR activation may contribute to the obesity-related enhanced susceptibility to colon carcinoma.     

Some effects of darkness and partial defoliation on the resistance of sugar beet to downy mildew

Seedlings of two susceptible sugar-beet stocks were grown either in daylight or in darkness for 24 h before or after inoculation with Peronospora farinosa f.sp. betae. Post-inoculation darkness did not significantly affect the percentage of inoculated plants that became infected but increased the percentage of plants on which the fungus sporulated in both stocks. The effects on sporulation of darkness before inoculation were more variable than those of post-inoculation darkness. In the same stocks removal of all leaves, except those in the bud, before inoculation increased the percentage both of plants which became infected and of those on which P. farinosa sporulated. Infection and sporulation were not significantly affected by defoliation in a more resistant stock. Defoliation or darkness may have affected the concentration of certain sugars or amino acids in the bud leaves thereby changing the expression of polygenically-controlled resistance to downy mildew.     

Host control over infection and proliferation of a cheater symbiont

Host control mechanisms are thought to be critical for selecting against cheater mutants in symbiont populations. Here, we provide the first experimental test of a legume host’s ability to constrain the infection and proliferation of a native‐occurring rhizobial cheater. Lotus strigosus hosts were experimentally inoculated with pairs of Bradyrhizobium strains that naturally vary in symbiotic benefit, including a cheater strain that proliferates in the roots of singly infected hosts, yet provides zero growth benefits. Within co‐infected hosts, the cheater exhibited lower infection rates than competing beneficial strains and grew to smaller population sizes within those nodules. In vitro assays revealed that infection‐rate differences among competing strains were not caused by variation in rhizobial growth rate or interstrain toxicity. These results can explain how a rapidly growing cheater symbiont – that exhibits a massive fitness advantage in single infections – can be prevented from sweeping through a beneficial population of symbionts.     

Changing Patterns of Infant Mortality and Maternal Fertility among Pumé Foragers and Horticulturalists

National census data show that the modern demographic transition—the recent trend toward declining mortality and fertility—is well underway in most countries. A different picture emerges when data from small-scale societies in unindustrialized parts of the world are considered. Many of these small-scale societies are also adapting to rapid changes in their subsistence economies. In this article, we examine the relationship between the pace of acculturation, infant mortality, and fertility levels among Pumé foragers and horticulturalists, two related groups of native South Americans. During the earliest stages of acculturation, Pumé horticulturalists experience not only a rapid drop in infant mortality but also a rise in birth rates. An anthropological view of demographic transitions provides important insight into how small-scale societies are affected by exposure to the labor market economy and has practical applications to effective development initiatives and public health policies.     

Use of resistant and susceptible potato cultivars in the trap cropping of potato cyst nematodes, Globodera pallida and G. rostochiensis

The effects of planting date and growing period of potato cultivars on their efficiency as trap crops for potato cyst nematodes (PCN) were studied. Plots were planted with susceptible or resistant cultivars in April, June and August and these were grown for 5, 6 or 7 wk before removal of the plants by hand lifting. Crops planted in June provided the best overall reductions in PCN population density of up to 95%, with cv. Santé significantly more effective than the other cultivars. Population reductions from the August planting were only slightly less than from planting in June but the tuber yields obtained were much greater: Maris Piper and Maris Bard produced 16.4 and 21.4 t ha^-1 respectively, with 37% and 43% respectively, of a size useful for canning (i.e. between 20 and 40 mm diameter).     

The effect of suspended sediments on Lake Texoma Daphnia: field distributions and in situ incubations

1. We measured the abundance and eggs per female of four Daphnia species in turbid and relatively clear regions of Lake Texoma (Oklahoma‐Texas, U.S.A.) on 12 dates over the course of 5 years. 2. Two species, Daphnia lumholtzi and Daphnia parvula, occurred and reproduced in turbid locations, but two other species, Daphnia mendotae and Daphnia pulicaria, occurred almost exclusively in relatively clear conditions. 3. To test the hypothesis that interference with foraging excludes clear‐water Daphnia species from turbid locations, we incubated adult D. mendotae at both a clear and a turbid site. In three successive experiments D. mendotae individuals incubated at the turbid site carried as many or more eggs than individuals incubated at the clear site.     

immunocytochemical localization of urokinase-type plasminogen activator in lewis lung carcinoma

The invasively growing and metasizing Lewis lung carcinoma consistently contained urokinase-type plasminogen activator (u-PA) enzyme activity. When investigated immunocytochemically with antibodies against u-PA, different parts of individual tumors showed a pronounced heterogeneity in staining intensity. Strong staining was found in areas with invasive growth and degradation of surrounding normal tissue, while other areas were completely devoid of staining. Immunoreactivity occurred both with a perinuclear cytoplasmic localization in tumor cells and associated with apparently extracellular material. SDS PAGE of tumor extracts, under both reducing and nonreducing conditions, followed by immunoblotting, showed only one immunocytochemically stainable band with an electrophoretic mobility corresponding to that of purified proenzyme to u-PA, while no two-chain u-PA was detected. This indicates that the major part of the activator in Lewis lung carcinoma is present as one-chain pro-u-PA.     

Scaling relationships within the maxillary tooth row of the Felidae, and the absence of the second upper premolar in Lynx

Suggestions that short-faced members of the Felidae tend to lack the second upper premolar (P2) imply a possible shift in scaling associated with the palate and maxillary tooth row in Lynx , which lacks P2, as compared to felids that retain it. This hypothesis is tested using a scaling model that relates the lengths of the palate, and the upper tooth row and its components, to post-palatal skull length in the small to moderately large felids Felis catus (domestic cat), L. canadensis (Canada lynx), F. pardalis (ocelot), and F. concolor (cougar). Scaling relationships of both palate and tooth row length to post-palatal skull length do not differ significantly from isometry in all four species. However, ocelots have a significantly shorter palate and tooth row than lynxes over their overlapping ranges of post-palatal skull length, suggesting that the absence of P2 is not correlated with the length of the face in these species. CI, P3 and P4 tend to be relatively longer in larger felids; none the less, ocelots have a relatively small P3 and lynxes have a proportionately large P4. Because both lynxes and ocelots have a relatively small gap between CI and P3, the absence of P2 is not correlated with available space within the tooth row in adults. However, lynxes also appear to have a relatively long dP3 that almost obliterates the diastema within the deciduous tooth row. The absence of P2 in Lynx may be an engineering artefact that is associated with a shift in proportions within the deciduous toothrow, resulting in inhibition of the development of P2 and dP2 early in ontogeny. Despite the variable occurrence and polymorphism associated with P2 in the Felidae, this character has systematic value within this clade and is a synapomorphy for Lynx.