Selective growth of malignant cells by in vitro incubation on Teflon

The selective growth of malignant cells on non-adhesive Teflon substrates is reported. Neoplastically transformed cell lines of human and murine origin proliferated on Teflon whereas similarly seeded normal non-tumorigenic cells were unable to undergo cell division and subsequent growth. This substrate should be especially useful in establishing primary cultures from human tumor material.     

Effect of p-chlorophenylalanine on the reproduction of the rat (author's transl)]

The effect of p-chlorophenylalanie (p-CPA) --300 mg/kg-- on reproduction has been studied in the female rat. Groups of animals were injected with a dose of 300 mg/kg of p-CPA 48 hours before proper copulation conditions at different moments along the ovarian cycle. Presence of spermatozoa in the vaginal frotis was negative in treated rats; in the control groups however, positivity was found in variable proportions according to the phase of the ovarian cycle: 30 ad 90% in diestrus and proestrus respectively. Treated animals showed continuous diestrus phases and diffuse luteinitation of the ovary. The results may indicate that a decrease of cerebral 5-HT, caused by p-CPA, lessens the reproductive behaviour of the female rat through mechanisms depending probably on the liberation of gonadrotrophins.     

Influence of nutrition on reproduction in the ewe with special emphasis on progesterone concentration.

Influence of nutrition on lambing rate and progesterone levels was studied in Rambouillet ewes. In the first experiment, two groups of 10 ewes each were individually fed on a diet containing either high (3.04 kg/day) or low (1.89 kg/day) levels of total digestible nutrients. Ewes on the High Plane of nutrition had lower pregnancy rates and fewer lambs than the ewes on the Low Plane. Plasma progesterone concentration was not significantly different between treatment groups when compared before and after mating.In the second experiment two groups of 25 ewes each were grazed on pasture and supplemented with a pelleted concentrate. One group was fed to gain weight, while the other group was fed to maintain their body weight. There was no significant difference in lambing rate between these two groups.     

Excess Maternal Salt Intake Produces Sex-Specific Hypertension in Offspring: Putative Roles for Kidney and Gastrointestinal Sodium Handling

Hypertension is common and contributes, via cardiovascular disease, towards a large proportion of adult deaths in the Western World. High salt intake leads to high blood pressure, even when occurring prior to birth – a mechanism purported to reside in altered kidney development and later function. Using a combination of in vitro and in vivo approaches we tested whether increased maternal salt intake influences fetal kidney development to render the adult individual more susceptible to salt retention and hypertension. We found that salt-loaded pregnant rat dams were hypernatraemic at day 20 gestation (147±5 vs. 128±5 mmoles/L). Increased extracellular salt impeded murine kidney development in vitro, but had little effect in vivo. Kidneys of the adult offspring had few structural or functional abnormalities, but male and female offspring were hypernatraemic (166±4 vs. 149±2 mmoles/L), with a marked increase in plasma corticosterone (e.g. male offspring; 11.9 [9.3–14.8] vs. 2.8 [2.0–8.3] nmol/L median [IQR]). Furthermore, adult male, but not female, offspring had higher mean arterial blood pressure (effect size, +16 [9–21] mm Hg; mean [95% C.I.]. With no clear indication that the kidneys of salt-exposed offspring retained more sodium per se, we conducted a preliminary investigation of their gastrointestinal electrolyte handling and found increased expression of proximal colon solute carrier family 9 (sodium/hydrogen exchanger), member 3 (SLC9A3) together with altered faecal characteristics and electrolyte handling, relative to control offspring. On the basis of these data we suggest that excess salt exposure, via maternal diet, at a vulnerable period of brain and gut development in the rat neonate lays the foundation for sustained increases in blood pressure later in life. Hence, our evidence further supports the argument that excess dietary salt should be avoided per se, particularly in the range of foods consumed by physiologically immature young.     

Linking behavioral states to landscape features for improved conservation management

1. A central theme for conservation is understanding how animals differentially use, and are affected by change in, the landscapes they inhabit. However, it has been challenging to develop conservation schemes for habitat‐specific behaviors.
2. Here we use behavioral change point analysis to identify behavioral states of golden eagles (Aquila chrysaetos) in the Sonoran and Mojave Deserts of the southwestern United States, and we identify, for each behavioral state, conservation‐relevant habitat associations.
3. We modeled behavior using 186,859 GPS points from 48 eagles and identified 2,851 distinct segments comprising four behavioral states. Altitude above ground level (AGL) best differentiated behavioral states, with two clusters of short‐distance movement behaviors characterized by low AGL (state 1 AGL = 14 m (median); state 2 AGL = 11 m) and two associated with longer‐distance movement behaviors and characterized by higher AGL (state 3 AGL = 108 m; state 4 AGL = 450 m).
4. Behaviors such as perching and low‐altitude hunting were associated with short‐distance movements in updraft‐poor environments, at higher elevations, and over steeper and more north‐facing terrain. In contrast, medium‐distance movements such as hunting and transiting were over gentle and south‐facing slopes. Long‐distance transiting occurred over the desert habitats that generate the best updraft.
5. This information can guide management of this species, and our approach provides a template for behavior‐specific habitat associations for other species of management concern.

     

Turnover and trends in butterfly communities on two British tidal islands: stochastic influences and deterministic factors

Aim Community trends were investigated for two small islands and two local mainland butterfly communities within the UK over a period of 20–30 years. Location Hilbre Island off the Wirral Peninsula at 53.33° N, 3.10° W; Lindisfarne, an island off the Northumberland coast at 56.41° N, 1.48° W; Leighton Moss at 54.08° N, 2.26° W; Wyre Forest at 52.23° N, 2.14° W, UK. Methods Butterfly species data were collected on Hilbre and two mainland sites (Leighton Moss and Wyre Forest) from 1983 to 2006, and on Lindisfarne from 1977 to 2006, as part of the National Habitat Survey, the UK Butterfly Monitoring Scheme and ‘Butterflies for the New Millennium Atlas’ recording. Matrices of associations (Sokal and Michener’s matching coefficient S_SM; resemblance coefficient) were computed between years and subject to non‐metric multidimensional scaling (NMDS) and Mantel tests. The pattern of extinctions and colonizations at sites were examined, their heterogeneity tested by applying a Friedman test to fractional incidences for the same years. Regression analysis (multiple regression and logit regression) was used to relate butterfly numbers and incidences to climate variables, time and previous records. Results Significant community trends based on population counts and species’ incidences were found for all four sites. There was a significant climatic signal for Hilbre; although this was not apparent for the remaining sites, significant associations occurred between records for a number of species and climatic variables at all sites. Substantial turnover of species on the islands was inversely related to numbers of records for species but not to their conspicuousness to recorders. Main conclusions We argue that time trends are widespread in butterfly communities, even for relatively short periods; they are largely generated by stochastic influences rather than by more substantive factors such as climate change. Potential biases in surveying and recording history are shown to be unlikely. A clear climate signal was found only for the small Hilbre Island, for which there was also evidence for the significant influence of colonization capability of individual source species. We conclude that for many species, small islands will be sinks or pseudosinks and their ‘populations’ vulnerable to small changes in source–sink dynamics.     

Total ecosystem carbon stocks at the marine‐terrestrial interface: Blue carbon of the Pacific Northwest Coast,United States

The coastal ecosystems of temperate North America provide a variety of ecosystem services including high rates of carbon sequestration. Yet, little data exist for the carbon stocks of major tidal wetland types in the Pacific Northwest, United States. We quantified the total ecosystem carbon stocks (TECS) in seagrass, emergent marshes, and forested tidal wetlands, occurring along increasing elevation and decreasing salinity gradients. The TECS included the total aboveground carbon stocks and the entire soil profile (to as deep as 3 m). TECS significantly increased along the elevation and salinity gradients: 217 ± 60 Mg C/ha for seagrass (low elevation/high salinity), 417 ± 70 Mg C/ha for low marsh, 551 ± 47 Mg C/ha for high marsh, and 1,064 ± 38 Mg C/ha for tidal forest (high elevation/low salinity). Soil carbon stocks accounted for >98% of TECS in the seagrass and marsh communities and 78% in the tidal forest. Soils in the 0–100 cm portion of the profile accounted for only 48%–53% of the TECS in seagrasses and marshes and 34% of the TECS in tidal forests. Thus, the commonly applied limit defining TECS to a 100 cm depth would greatly underestimate both carbon stocks and potential greenhouse gas emissions from land‐use conversion. The large carbon stocks coupled with other ecosystem services suggest value in the conservation and restoration of temperate zone tidal wetlands through climate change mitigation strategies. However, the findings suggest that long‐term sea‐level rise effects such as tidal inundation and increased porewater salinity will likely decrease ecosystem carbon stocks in the absence of upslope wetland migration buffer zones.