Riochemical and physiological effects in farmed Baltic salmon fed lipids containing xenobiotics extracted from Baltic herring

During a 2-year experimental period female baltic salmon (Salmo salar) were fed pellets impregnated with oil extracted from Baltic herring (Clupea harengus). This extract contained lipid-soluble xenobiotics present in Baltic herring, which constitute a major part of the natural diet of Baltic salmon. The fish were examined at the time of ovulation in November each year. After 2 years of feeding, the load of polychlorinated dibenzo-paradioxins and furans in the exposed group was about twice that in the control group, but still low compared with concentrations in feral Baltic salmon. In spite of the relatively low exposure level, several vital biochemical functions were disturbed in the treated fish. Organic skeletal variables were affected indicating that the bone metabolism had been altered. Furthermore, the activities of enzymes involved in steroid biosynthesis were affected, which could lead to disturbances in reproductive functions. Splenocytes from exposed fish sampled in November 1990 showed a reduced mitogenic response, indicating that their immune system was suppressed. Feeding the salmon with pollutant-impregnated pellets also resulted in an induction of the hepatic ethoxyresorufin-O-deethylase (EROD) activity after only 6 weeks of exposure. Likewise, morphological abnormalities, i.e. hypertrophic hepatocytes and various stages of hepatic degeneration, were already apparent after 6 weeks of exposure. However, no EROD induction or morphological responses were recorded at the second and third sampling event, i.e. after one and 2 years of exposure, respectively. this could indicate that some physiological functions may adapt to a restricted xenobiotic load.     

Intra-host competition between co-infecting digeneans within a bivalve second intermediate host: Dominance by priority-effect or taking advantage of others?

We experimentally investigated the interactions between two parasites known to manipulate their host's phenotype, the trematodes Acanthoparyphium sp. and Curtuteria australis, which infect the cockle Austrovenus stutchburyi. The larval stages of both species encyst within the tissue of the bivalve's muscular foot, with a preference for the tip of the foot. As more individuals accumulate at that site, they impair the burrowing behaviour of cockles and increase the probability of the parasites' transmission to a bird definitive host. However, individuals at the foot tip are also vulnerable to non-host predators in the form of foot-cropping fish which selectively bite off the foot tip of exposed cockles. Parasites encysted at the foot base are safe from such predators although they do not contribute to altering host behaviour, but nevertheless benefit from host manipulation as all parasites within the cockle are transmitted if it is ingested by a bird. Experimental infection revealed that Acanthoparyphium sp. and C. australis have different encystment patterns within the host, with proportionally fewer Acanthoparyphium metacercariae encysting at the foot tip than C. australis. This indicates that Acanthoparyphium may benefit indirectly from C. australis and incur a lower risk of non-host predation. However, in co-infections, not only did C. australis have higher infectivity than Acanthoparyphium, it also severely affected the latter's infection success. The asymmetrical strategies and interactions between the two species suggest that the advantages obtained from exploiting the host manipulation efforts of another parasite might be offset by traits such as reduced competitiveness in co-infections.     

Macaques preferentially attend to intermediately surprising information

Normative learning theories dictate that we should preferentially attend to informative sources, but only up to the point that our limited learning systems can process their content. Humans, including infants, show this predicted strategic deployment of attention. Here, we demonstrate that rhesus monkeys, much like humans, attend to events of moderate surprisingness over both more and less surprising events. They do this in the absence of any specific goal or contingent reward, indicating that the behavioural pattern is spontaneous. We suggest this U-shaped attentional preference represents an evolutionarily preserved strategy for guiding intelligent organisms toward material that is maximally useful for learning.     

Quantitative proteomics reveals differentially expressed proteins in murine preneoplastic intestine in a model of intestinal tumorigenesis induced by low dietary folate and MTHFR deficiency

Colorectal cancer risk is increased when dietary folate intake is low, with or without a deficiency in methylenetetrahydrofolate reductase (MTHFR). We have observed that intestinal tumors are induced in mice fed low‐folate diets, and that tumor incidence is increased when these mice also have MTHFR deficiency. This study was undertaken to identify differentially expressed proteins in conditions favoring initial steps of murine carcinogenesis in normal preneoplastic intestine. We compared the proteome of BALB/c normal intestine in Mthfr^+/+ mice fed control diets for 1 year (low susceptibility to tumorigenesis) with the proteome of Mthfr^+/? animals fed low folate diets (higher tumor susceptibility). Our data suggest that the NuRD complex, KRAS‐related proteins, the protein synthetic machinery, and fatty acid‐related metabolic proteins are upregulated in the early stages of tumorigenesis. These proteins may serve as biomarkers or targets for colorectal cancer diagnosis or therapy.     

Participant Profiling and Pattern of Crop-Foraging in Chacma Baboons (<Emphasis Type="Italic">Papio hamadryas ursinus</Emphasis>) in Zimbabwe: Why Does Investigating Age–Sex Classes Matter?

Transformation and loss of natural habitat to urbanization and agriculture provide new opportunities for primates to feed on anthropogenic food sources. Currently, mitigation strategies fail to target the individuals responsible for initiating and maintaining this behavior. As primates mainly forage on crops in groups, we investigate the crop-foraging behavior of a group of 40 chacma baboons in Zimbabwe from the perspective of collective movements, i.e., when a group of animals move together in the same direction, thus resulting in a change of location. We collected data on 110 crop-foraging events during 35 days in March–April 2014. We recorded baboon movement and behavior with a camcorder and obtained further information through video analysis. Most crop-foraging events involved less than 20% of the troop and lasted less than 3 min. Although crop-foraging parties were composed of all age–sex classes, adult females and particularly adult males initiated most crop-foraging events and made direct movements (without stopping on the road) more often than nonadult participants. Baboons made up to five successive attempts to crop forage in a single crop-foraging event. Neither the number of participants nor the success of the crop-foraging events increased over the successive attempts. Finally, crop-foraging events were more successful and more frequent in unguarded areas than in guarded areas. These results suggest that group members are highly synchronized and that crop-foraging is based on a collective decision such as classical foraging movements. In addition, the short duration of the crop-foraging events might prevent detection of baboons by farmers. The more frequent initiation of crop-foraging by adults compared to nonadults might be explained by greater energetic needs or a greater tendency of adults to take risks. These preliminary data can help inform long-term strategies for farmers to reduce crop losses to baboons, as guarding helps reduce damage but does not prevent it.     

Toward preclinical predictive drug testing for metabolism and hepatotoxicity by using in vitro models derived from human embryonic stem cells and human cell lines - a report on the Vitrocellomics EU-project

Drug-induced liver injury is a common reason for drug attrition in late clinical phases, and even for post-launch withdrawals. As a consequence, there is a broad consensus in the pharmaceutical industry, and within regulatory authorities, that a significant improvement of the current in vitro test methodologies for accurate assessment and prediction of such adverse effects is needed. For this purpose, appropriate in vivo-like hepatic in vitro models are necessary, in addition to novel sources of human hepatocytes. In this report, we describe recent and ongoing research toward the use of human embryonic stem cell (hESC)-derived hepatic cells, in conjunction with new and improved test methods, for evaluating drug metabolism and hepatotoxicity. Recent progress on the directed differentiation of human embryonic stem cells to the functional hepatic phenotype is reported, as well as the development and adaptation of bioreactors and toxicity assay technologies for the testing of hepatic cells. The aim of achieving a testing platform for metabolism and hepatotoxicity assessment, based on hESC-derived hepatic cells, has advanced markedly in the last 2-3 years. However, great challenges still remain, before such new test systems could be routinely used by the industry. In particular, we give an overview of results from the Vitrocellomics project (EU Framework 6) and discuss these in relation to the current state-of-the-art and the remaining difficulties, with suggestions on how to proceed before such in vitro systems can be implemented in industrial discovery and development settings and in regulatory acceptance.