The use of predator tags to explain reversal movement patterns in Atlantic salmon smolts (Salmo salar L.).

Acoustic telemetry has seen a rapid increase in utility and sophistication in recent years and is now used extensively to assess the behavior and survival rates of many aquatic animals, including the Atlantic salmon. As part of the salmon's complex life cycle, salmon smolts are thought to make a unidirectional migration from fresh water to the sea, which is initiated by changes in their physiology. However, some tag movement patterns do not conform with this and can be difficult to explain, particularly if the tagged fish has been eaten by a predator. This study combines the use of predator tags with machine learning techniques to understand the fate of migrating salmon smolts and thereby improve estimates for migration success. Over 3 years between 2020 and 2022, 217 salmon smolts (including wild and hatchery-reared ranched fish) were acoustically tagged and released into an embayment on the west coast of Ireland. Some tagged smolts were observed to return from the estuary back into a saline lagoon through which they had already migrated. To distinguish between the movement of a salmon smolt and that of a predator, predator tags were deployed in migrating smolts in 2021 and 2022. The addition of a temperature sensor in 2022 enabled the determination of predator type causing the returning movement. A significant number of predator tags were triggered, and the patterns of movement associated with these triggered tags were then used with two types of machine learning algorithms (hierarchical cluster analysis and random forest) to identify and validate the behavior of smolts tagged without extra sensors. Both models produced the same outputs, grouping smolts tagged with predator tags with smolts tagged without the additional sensors but showing similar movements. A mammalian predator was identified as the cause of most reversal movement, and hatchery-reared ranched smolts were found to be more likely predated upon by this predator than wild smolts within the lake and the estuary. However, overall migration success estimates were similar for both wild and hatchery-reared ranched fish. This study highlights the value of predator tags as an essential tool in the overall validation of detection data.

The novel use of pop-off satellite tags (PSATs) to investigate the migratory behaviour of European sea bass Dicentrarchus labrax.

A total of 12 adult European sea bass Dicentrarchus labrax were tagged with pop-off satellite archival tags (PSAT) in Irish coastal waters and in offshore waters in the north-east Celtic Sea between 2015 and 2016. Archived data were successfully recovered from five of the 12 tags deployed, three from fish released in inshore Irish waters and two from fish released offshore in the eastern Celtic Sea. All three fish tagged in inshore waters were found to undertake migrations into the open ocean coinciding with the spawning period. These fish also exhibited fidelity to inshore sites post-migration, returning to the same general location (within c. 73 km, which is roughly the predicted mean accuracy of the method) of their original release site. Although the number of tracks obtained here was limited, some degree of aggregation between inshore and offshore tagged fish in the eastern Celtic Sea was noted during the expected spawning period suggesting PSATs can provide new information on specific spawning locations of European sea bass.

N-terminal or signal peptide sequence engineering prevents truncation of human monoclonal antibody light chains.

Monoclonal antibodies (mAbs) contain short N-terminal signal peptides on each individual polypeptide that comprises the mature antibody, targeting them for export from the cell in which they are produced. The signal peptide is cleaved from each heavy chain (Hc) and light chain (Lc) polypeptide after translocation to the ER and prior to secretion. This process is generally highly efficient, producing a high proportion of correctly cleaved Hc and Lc polypeptides. However, mis-cleavage of the signal peptide can occur, resulting in truncation or elongation at the N-terminus of the Hc or Lc. This is undesirable for antibody manufacturing as it can impact efficacy and can result in product heterogeneity. Here, we describe a truncated variant of the Lc that was detected during a routine developability assessment of the recombinant human IgG1 MEDI8490 in Chinese hamster ovary cells. We found that the truncation of the Lc was caused due to the use of the murine Hc signal peptide together with a lambda Lc containing an SYE amino acid motif at the N-terminus. This truncation was not caused by mis-processing of the mRNA encoding the Lc and was not dependent on expression platform (transient or stable), the scale of the fed-batch culture or clonal lineage. We further show that using alternative signal peptides or engineering the Lc SYE N-terminal motif prevented the truncation and that this strategy will improve Lc homogeneity of other SYE lambda Lc-containing mAbs. Biotechnol. Bioeng. 2017;114: 1970-1977. © 2017 Wiley Periodicals, Inc.

Presence of pesticide residues on produce cultivated in Suriname.

Agricultural pesticides are widely used in Suriname, an upper middle-income Caribbean country located in South America. Suriname imported 1.8 million kg of agricultural pesticides in 2015. So far, however, national monitoring of pesticides in crops is absent. Reports from the Netherlands on imported Surinamese produce from 2010 to 2015 consistently showed that samples exceeded plant-specific pesticide maximum residue limits (MRLs) of the European Union (EU). Consumption of produce containing unsafe levels of pesticide residues can cause neurological disorders, and particularly, pregnant women and children may be vulnerable. This pilot study assessed the presence of pesticide residues in commonly consumed produce items cultivated in Suriname. Thirty-two insecticides (organophosphates, organochlorines, carbamates, and pyrethroids) and 12 fungicides were evaluated for their levels in nine types of produce. Pesticide residue levels exceeding MRLs in this study regarded cypermethrin (0.32 µg/g) in tomatoes (USA MRL 0.20 µg/g), lambda-cyhalothrin (1.08 µg/g) in Chinese cabbage (USA MRL 0.40 µg/g), endosulfan (0.07 µg/g) in tannia (EU MRL 0.05 µg/g), and lindane (0.02 and 0.03 µg/g, respectively) in tannia (EU MRL 0.01 µg/g). While only a few pesticide residues were detected in this small pilot study, these residues included two widely banned pesticides (endosulfan and lindane). There is a need to address environmental policy gaps. A more comprehensive sampling and analysis of produce from Suriname is warranted to better understand the scope of the problem. Preliminary assessments, using intake rate, hazard quotient, and level of concern showed that it is unlikely that daily consumption of tannia leads to adverse health effects.

Familial and Bullying Victimisation: The Impact of Early Adversity Within the Home and Peer Settings on Late Adolescence and Adult Psychopathology.

Background: Awareness of adverse childhood experiences and their impact on adult psychopathology primarily focuses on adversities within the home. There is limited insight into the impact of adversities across peer environments. Objective: This study investigates 19 items related to adverse experiences across the home, school and peer environments and their relationship to 12-month and lifetime psychopathology. Data: Secondary analysis of the Ulster University Student Well-being Study. The dataset included completed responses across all selected variables for 729 participants. Method and Results: Latent profile analysis identified a low adversity profile, bullying adversity profile and higher prevalence adversity profile. Regression analysis of the three profiles and demographics variables indicated their impact on adult psychopathology lifetime and 12-month prevalence rates. Conclusion: Schools and HE institutions should acknowledge the impact of childhood adversities. In doing so, it is important to consider the deeper impact of bullying due to its links with psychopathology across the lifespan. Educational institutions should take appropriate steps to mitigate continued exposure as students' progress through the education system.

Nuptial coloration varies with ambient light environment in a freshwater fish.

Visual signals play a vital role in many animal communication systems. Signal design, however, often varies within species, raising evolutionarily important questions concerning the maintenance of phenotypic diversity. We analysed nuptial colour variation within and among nine populations of southern pygmy perch (Nannoperca australis Günther) along an environmental light gradient. Within populations, larger males were redder and blacker, and better-condition males were blacker. Among populations, red colour was positively correlated with the amount of orange-red light present, suggesting that males are likely optimizing signal conspicuousness by producing proportionally larger and redder patches in broad spectrum environments with more orange-red light. Signal contrast, in this regard, is maximized when red colour, appearing bright because of the prevalence of red wavelengths, is viewed against the water-column background. Together, our results are concordant with the sensory drive hypothesis; selection favours signal adaptations or signal plasticity to ensure communication efficacy is maximized in different light environments.

Effects of dietary restriction on radial-arm maze performance and flavor memory in aged rats.

Two groups of aged rats, a dietary restricted group fed approximately 10 g per day from 6 weeks of age and a group fed ad lib throughout their life span, were compared with a young adult group on an 8-arm radial maze and a flavor memory task. The young adult displayed efficient performance on the radial-arm maze within the 15 day test period. In contrast, both aged groups exhibited significantly poorer performance in the maze in comparison with the young adult group neither aged group differed from chance at the end of the 15 days. The flavor memory task required the animals to consume a novel flavor. Their loss of neophobia, as indexed by their subsequent consumption, was then taken as an indication of the extent to which they remembered the novel flavor and its effects. The young adult group lost their neophobia more rapidly than either of the aged groups, which did not appear to differ from each other. Taken together, this pattern of results indicates that dietary restriction does not protect animals from the memory loss observed in aged animals.

Resistance to extinction of fear-relevant stimuli: preparedness or selective sensitization?

Human conditioning research has revealed an apparent resistance to extinction of aversive conditioning to pictures of fear-relevant stimuli such as snakes and spiders, supporting M. E. P. Seligman's (1971) preparedness theory of fears and phobias. This article examines an alternative account based on activation of preexisting response tendencies under threat (selective sensitization). Two experiments demonstrate that selective sensitization of electrodermal responses is attenuated when a fear-relevant stimulus serves as a negative conditioned stimulus (CS-), but is maintained when it serves as a positive conditioned stimulus (CS+). Previous extinction results may therefore be due to preservation of initial responding to CS+ but not CS-. Selective sensitization offers a model for the nonassociative activation of fears and phobias to prepotent stimuli under conditions of stress or threat. Possible genetic and cognitive mechanisms are discussed.

Ontogeny of activity in inbred and random-bred strains of mice: effects of scopolamine.

In Experiment 1, the activity of five inbred strains, A/J, BALB/c, C3H/HeJ, C57BL/6J, and DBA/2J, and two random-bred strains, Fullensdorf and Quackenbush, was observed at ages from 13 to 28 days. The C3H/HeJ, Fullensdorf, and Quackenbush strains exhibited a sharp increase in activity, to a peak at 17 days of age, followed by a decline at later ages. In contrast, the activity of the A/J, BALB/c, C57BL/6J, and DBA/2J mouse strains increased gradually, reaching a peak at 19 days of age. These mice displayed no decline in activity at later ages. In Experiment 2, mice from the five inbred strains and the Quackenbush strain were injected with either 0, 1.0, or 4.0 mg/kg of scopolamine before activity testing at 17, 21, or 28 days of age. Scopolamine had no effect on the activity of the various strains of mice at 17 or 21 days of age. At 28 days of age, the 4.0 mg/kg dose of scopolamine was associated with increased activity in all of the mouse strains.

Effects of prenatal ethanol exposure on avoidance conditioning in high- and low-avoidance rat strains.

Two lines of rats selected for high- and low-avoidance performance consumed a nutritious liquid diet containing 35% ethanol-derived calories through days 5--18 of gestation. Control dams were pair-fed an identical liquid diet except for isocaloric substitution of sucrose for ethanol or ad libitum laboratory chow and water. Subsequently, the offspring of the low-avoider dams fed ethanol were found to be impaired ona two-way shock-avoidance conditioning when compared to the pair-fed and ad libitum controls from the same line. In contrast, the offspring of the high-avoider dams fed ethanol displayed similar levels of avoidance, responding to their controls. These results demonstrate that the effects on avoidance conditioning of in utero ethanol exposure are dependent upon the line of rat studied.

Avoidance conditioning and Hebb-Williams maze performance in rats treated prenatally with alcohol.

Throughout gestation pregnant Wistar rats consumed a nutritious liquid diet containing 35% ethanol-derived calories. Control mothers were fed lab chow. Subsequently, the offspring of the ethanol-fed mothers were found to be impaired on two-way avoidance conditioning when compared to control offspring, but did not differ from controls in their performance on the Hebb-Williams maze. Fostering and cross-fostering procedures indicated that the effect was due to prenatal influences arising from the drug treatment.

Prenatal alcohol consumption and open-field behaviour in rats: effects of age at time of testing.

Throughout gestation pregnant Wistar rats consumed a nutritious liquid diet containing 35% ethanol-derived calories. Control mothers were fed lab-chow. Subsequently, the offspring of the ethanol-fed mothers displayed significantly greater activity (ambulation) in an open-field test at 28 and at 56 days of age, but not at 112 days of age. No differences in defecation were observed at any age.

The impact of inter-pellet interval and polydipsia on hypoalgesia elicited by non-contingent food delivery.

Exposure to non-contingent food delivery has been shown to elicit an increase in nociceptive thresholds in rats. The conditions which elicit analgesia are similar to those that elicit schedule-induced polydipsia. In both instances animals are food-deprived and receive food on an intermittent schedule. Interpellet interval has been found to be an important predictor of schedule-induced polydipsia. Experiment 1 therefore investigated the effect of varying the interval between pellet deliveries on tail flick latencies in rats. The relationship between nociceptive threshold and inter-pellet interval was found to be bitonic in nature given that animals submitted to fixed time schedules of 30 or 60 s, but not 15 or 120 s, exhibited significant increases in tail flick latencies. Experiment 2 examined the effect of providing animals with water during exposure to non-contingent food delivery. Under these conditions animals exhibited polydipsic behaviour, the development of which attenuated the hypoalgesic response to non-contingent food delivery.

The role of hypophyseal and adrenal mechanisms in the hypoalgesic response to non-contingent food delivery in the rat.

Exposure to non-contingent food delivery has been shown to elicit an increase in nociceptive thresholds in rats. This hypoalgesia has previously been shown to be reversible by the opiate antagonist naloxone. Given that most opioid forms of SIA are found to rely on an intact pituitary-adrenal axis, this research examined the possibility that the hypoalgesic response to non-contingent food delivery is also hormonally mediated. Hypophysectomy (Expt. 1) but not bilateral adrenalectomy (Expt. 2) was found to completely attenuate the hypoalgesic response to non-contingent food delivery. Preliminary data from ongoing research is presented that points to the possible involvement of the hypophyseal peptides beta-endorphin and adrenocorticotropin hormone (ACTH).

Control of food delivery in food-deprived rats mediates analgesia.

An experiment was carried out to investigate the effects of control of food delivery, in food-deprived rats, on analgesia. Tail flick latency was used as an index of pain sensitivity and naloxone reversibility of analgesia was used as the criterion for opioid involvement. Food-deprived rats were submitted to one of two schedules of food delivery. The 'contingent' group could control the delivery of food by lever-pressing. The 'non-contingent' group received the same number of food pellets but delivery of food was independent of lever-pressing behaviour. Animals in the 'control' group were placed in the test chamber but did not receive any pellets. Subjects were tested on 6 consecutive days, each test session being of 10 min duration. Half of the animals in each group received an intraperitoneal injection of saline (0.5 ml) prior to each test session, the other half received an intraperitoneal injection of naloxone (5 mg/kg in 0.5 ml saline) prior to each session. Both contingent and non-contingent food delivery resulted in a significant post-test analgesia. The analgesia was noticeably greater when food delivery was non-contingent and this analgesia was reversible by naloxone. The findings suggest that non-contingent food delivery, in food-deprived rats, elicits an opioid analgesia, whilst contingent food delivery elicits a non-opioid analgesia.

Short- and long-term decrements in toxicosis-induced odor-aversion learning: the role of duration of exposure to an odor.

Six experiments employed an odor-aversion paradigm to investigate the role of the duration of exposure to an odor in determining that odor's subsequent associability with illness. Rats were exposed to an odor at times T1 and T2, and the second of these exposures was followed by toxicosis. When the initial odor exposure was brief, the odor aversion was attenuated with a moderate T1-T2 interval of 3 hr (Experiment 1) but not with long intervals of 28 hr and 76 hr (Experiment 2). In contrast, when the initial odor exposure was long, the odor aversion was attenuated at a long T1-T2 interval (Experiment 3). With a T1-T2 interval of 24 hr, a brief initial exposure did not attenuate odor aversions when the context either remained the same or was changed from T1 to T2, whereas a long initial exposure attenuated such aversions when the context remained the same but not when the context was changed (Experiment 4). With a T1-T2 interval of 3 hr, a brief initial exposure attenuated odor aversions when the context remained the same or was changed from T1 to T2, whereas a long initial exposure attenuated such aversions when the context remained the same but not when the context was changed (Experiment 5). A brief exposure at T1, either with or without a subsequent context "extinction," attenuated odor aversions when the T1-T2 interval was 3 hr but not when this interval was 24 hr; a long initial exposure at T1, without a subsequent context "extinction," attenuated odor aversions when the T1-T2 interval was 4 hr and 24 hr but with a subsequent context "extinction" did not attenuate such aversions at either 4-hr or 24-hr T1-T2 intervals (Experiment 6). The results demonstrate that the duration of exposure to an odor determined whether that odor presentation caused short- or long-term decrements in odor conditionability and are discussed in terms of the relation between self- and retrieval-generated processes.

Conditioned suppression, heart rate and pulse volume: effects of instructions on extinction.

Two experimental groups of undergraduate volunteers received five classical aversive conditioning trials with a tone conditioned stimulus (CS) and shock unconditioned stimulus (UCS). Control groups received either the CS alone or UCS alone. Subjects from one experimental group were subsequently instructed that they would not receive further shocks, while the other experimental group received no such instructions. The CS alone was then presented once to all four groups while subjects were engaged in a button-pressing task maintained by slide reinforcement. During this latter phase rate of button pressing was measured as well as heart rate and pulse volume. The last two measures being employed as indices of autonomic arousal. The results indicated that while instructions as to the absence of the UCS completely abolished the conditioned suppression of button-pressing, they had no effect upon the pulse volume CR. A heart rate CR was not obtained. These results reflect unfavourably upon theoretical formulations of conditioned suppression that emphasize the causal interdependence of motor and autonomic events or the primacy of either one.

Avoidance learning, Pavlovian conditioning, and the development of phobias.

This paper examines the role of Pavlovian conditioning in the acquisition, maintenance and elimination of human phobias. Because many conceptualizations of human fears and phobias are based on data from studies of avoidance learning in animals, we first review theories of avoidance. Our conclusion is that none of the extant theories provides an adequate account of avoidance learning, and we propose a model of avoidance that involves Pavlovian, but not instrumental learning. We then analyse critically arguments that Pavlovian conditioning plays only a small role in the aetiology of fears. Finally, the paper examines the implications of a conditioning model of avoidance for the study of human fears and phobias.

Restoration of memory following septo-hippocampal grafts: a possible treatment for Alzheimer's disease.

The present paper outlines the reasons for the current interest in work on septo-hippocampal grafts. It examines the role of cholinergic dysfunction in the memory deficits associated with Alzheimer's disease, the effects of hippocampal lesions on memory in infra-human animals, and the anatomy of the hippocampus. Methodological aspects of neural grafting are then examined, including the source, nature and site of the graft. A review of the tasks employed to determine functional recovery following septo-hippocampal grafts suggests that although recovery is evident its nature is unclear. An experiment is described which suggests that grafts from embryonic septum bring about recovery of working memory in rats. Different bases of the recovery of function are discussed, including the role of the graft in eliciting release of trophic factors from the host brain; the possibility that the graft acts by providing a pool of neurotransmitter; and finally that the graft may replace the damaged circuitry of the host. Some problems of the grafting procedure are outlined. It is concluded that grafting may provide a viable treatment technique in the absence of other forms of treatment for Alzheimer's disease.

Effects of social anxiety and facial expression on habituation of the electrodermal orienting response.

The present research examined electrodermal orienting to happy and angry faces as a function of social anxiety and threat of shock. A preliminary study using 569 undergraduate participants developed an adequate set of normative data of social anxiety for the Willoughby questionnaire (WQ) for use in subject selection. Electrodermal activity was measured in both high and low socially anxious subjects (N = 85) during exposure to 10 presentations of an angry face intermixed with 10 presentations of a happy face. Threat of shock (no-shock, shock work-up only, and shock work-up plus threat) was also manipulated. Skin conductance responses (SCRs) which occurred within 1-4 s of stimulus onset and trials-to-habituation constituted the data of primary interest. Although trials-to-habituation did not differ between angry and happy facial expressions, SCRs were larger to the angry face than to the happy face in both high and low socially anxious subjects. No differences in SCR magnitude were found as a function of threat of shock. The implications of these results for Ohman's functional-evolutionary model of social phobia are discussed, and alternative explanations in terms of prepotency and prior learning are examined.