bluuebunny/crossref_metadata_2025 huggingface dataset:
Double checking medicines: defence against error or contributory factor?
Authors: Armitage Gerry
Published: September 2007

Rationale and aim  The double checking of medicines in health care is a contestable procedure. It occupies an obvious position in health care practice and is understood to be an effective defence against medication error but the process is variable and the outcomes have not been exposed to testing. This paper presents an appraisal of the process using data from part of a larger study on the contributory factors in medication errors and their reporting.

Methods  Previous research studies are reviewed; data are analysed from a review of 991 drug error reports and a subsequent series of 40 in‐depth interviews with health professionals in an acute hospital in northern England.

Results  The incident reports showed that errors occurred despite double checking but that action taken did not appear to investigate the checking process. Most interview participants (34) talked extensively about double checking but believed the process to be inconsistent. Four key categories were apparent: deference to authority, reduction of responsibility, automatic processing and lack of time. Solutions to the problems were also offered, which are discussed with several recommendations.

Conclusions  Double checking medicines should be a selective and systematic procedure informed by key principles and encompassing certain behaviours. Psychological research may be instructive in reducing checking errors but the aviation industry may also have a part to play in increasing error wisdom and reducing risk.
The development of probiotics for the control of multiple bacterial diseases of rainbow trout, Oncorhynchus mykiss (Walbaum)
Authors: Brunt J , Newaj‐Fyzul A , Austin B
Published: September 2007

JB‐1 and GC2, which were equated with Bacillus sp. and Aeromonas sobria respectively, were recovered from the digestive tract of rainbow trout, Oncorhynchus mykiss and ghost carp, Cyprinus sp. respectively, and demonstrated effectiveness as probiotics for the control of infections caused by Aeromonas salmonicida, Lactococcus garvieae, Streptococcus iniae, Vibrio anguillarum, Vibrio ordalii and Yersinia ruckeri. When administered to rainbow trout (average weight = 12 g) for 14 days in feed dosed at 2 × 108 cells g−1 of feed, JB‐1 led to a reduction in mortalities to 0–13% after challenge with a range of bacterial pathogens compared to 80–100% mortalities of the controls. Similarly, use of GC2 reduced mortalities to 0–16% following the challenge compared to 80–100% mortalities of the controls. The mode of action reflected nutrition, production of inhibitory substances and stimulation of the innate immune responses. Specifically, JB‐1 and especially GC2 were positive for siderophore and chitinase production, and increased lysozyme, phagocytic and respiratory burst activity.
Susceptibility of channel catfish, Ictalurus punctatus (Rafinesque), to Edwardsiella ictaluri challenge following copper sulphate exposure
Authors: Griffin B R , Mitchell A J
Published: September 2007

Channel catfish, Ictalurus punctatus (Rafinesque), with or without a preliminary 24 h exposure to 2 mg copper sulphate L−1, were challenged with 7.5 × 106 colony forming units L−1 of Edwardsiella ictaluri to determine the effect of copper sulphate on disease resistance. Catfish previously exposed to copper sulphate were significantly more resistant to the bacterial challenge than those not exposed. Catfish not exposed to copper sulphate suffered 35.5% mortality while catfish exposed to copper sulphate experienced 14.1% mortality. Copper concentrations were the same in tank waters of both exposed and control fish at the time of challenge, eliminating the possibility that copper in the water may have been toxic to bacteria. Copper concentrations in freeze dried and ground tissues of unexposed, exposed, and purged channel catfish were highest in fish before copper sulphate exposures suggesting that elevated tissue levels of copper were not responsible for the increased resistance to bacterial challenge. Competition for sites of bacterial attachment to gill or epithelial cells may account for the reduction in mortality; although this is not supported by the low copper content of fish tissue after copper exposure.
Experimental exposure of zebrafish, Danio rerio (Hamilton), to Mycobacterium marinum and Mycobacterium peregrinum reveals the gastrointestinal tract as the primary route of infection: a potential model for environmental mycobacterial infection
Authors: Harriff M J , Bermudez L E , Kent M L
Published: September 2007

The natural route by which fish become infected with mycobacteria is unknown. Danio rerio (Hamilton) were exposed by bath immersion and intubation to Mycobacterium marinum and Mycobacterium peregrinum isolates obtained from diseased zebrafish. Exposed fish were collected over the course of 8 weeks and examined for the presence of mycobacteriosis. Mycobacteria were consistently cultured from the intestines, and often from the livers and spleens of fish exposed by both methods. Mycobacteria were not observed in the gills. Histological analysis revealed that fish infected with M. marinum often developed granulomas accompanied by clinical signs of mycobacteriosis, while infection with M. peregrinum infrequently led to clinical signs of disease. Passage of the bacteria through environmental amoebae (Acanthamoeba castellani) was associated with increased growth of M. peregrinum over the course of 8 weeks, when compared to infection with the bacteria not passed through amoebae. The results provide evidence that zebrafish acquire mycobacteria primarily through the intestinal tract, resulting in mycobacterial dissemination.
Increased systemic vascular resistance in Atlantic salmon, Salmo salar L., affected with amoebic gill disease
Authors: Leef M J , Hill J V , Harris J O , Powell M D
Published: September 2007

Previous investigations into the pathophysiology of amoebic gill disease (AGD) have suggested that there are probable cardiovascular effects associated with this disease. In the present study Atlantic salmon, Salmo salar L., were experimentally infected by cohabitation with diseased individuals. Two commonly used vasodilators, sodium nitroprusside (SNP) and captopril, the angiotensin‐converting enzyme (ACE) inhibitor, were used as tools to investigate possible vasoconstriction and/or renin–angiotensin system (RAS) dysfunction in AGD‐affected animals. Within the SNP trial, results showed that AGD‐affected fish exhibited lowered cardiac output (Q), lowered cardiac stroke volume (VS) and a significantly elevated systemic vascular resistance (RS) compared with non‐affected naïve counterparts. These effects were totally abolished following SNP administration (40 μg kg−1), however significant cardiovascular effects associated with SNP were not observed. Within the captopril trial, where AGD‐affected fish were more diseased compared with the SNP trial, a significant hypertension was observed in AGD‐affected fish. Captopril administration (10−4 mol L−1 at 1 mL kg−1) resulted in a significant drop in dorsal aortic pressure (PDA) for both AGD‐affected and naïve control fish. In terms of peak individual responses, captopril administration effectively lowered PDA in both AGD‐affected and naïve control groups equally. The drop in PDA following SNP administration however was significantly greater in AGD‐affected fish potentially suggesting disease‐related vasoconstriction. The lack of significant cardiovascular effects directly associated with both SNP and captopril administrations possibly relate to the 6 h recovery period following surgical procedures. However, while variable, these results do suggest that there are significant cardiovascular effects including vasoconstriction and hypertension associated with AGD.
Suspected myocardial necrosis in farmed Atlantic salmon, Salmo salar L.: a field case
Authors: Poppe T T , Taksdal T , Bergtun P H
Published: September 2007

Arteriosclerosis of the coronary artery has been described as a ‘fact of life’ for Pacific and Atlantic salmonids due to the high prevalence in spawning fish. The lesions are believed to be the result of overstretching of the highly distensible bulbus arteriosus whereby the endothelium of the main coronary vessel becomes mechanically damaged and a smooth muscle proliferation ensues with resultant partial occlusion of the vessel. The physiological significance for the function of the heart has yet to be demonstrated, but experimental studies show that, for example, swimming performance is compromised in fish in which the coronary artery has been ligated. This paper describes a case of myocardial necrosis in harvest‐size Atlantic salmon during and after transportation to the slaughterhouse. Mortality during this process reached 10% in some of the transports and affected fish showed characteristic signs of congestive cardiac failure. Histology revealed extensive myointimal proliferation in the coronary artery and patchy necrosis of the compact ventricular myocardium. Several unfavourable factors such as high water temperature, skeletal malformations and crowding all probably contributed to extra cardiac workload. To the best of our knowledge, this is the first reported field case showing a link between coronary lesions and severe cardiac pathology.
Detection of infectious pancreatic necrosis virus (IPNV) from the environment in the vicinity of IPNV‐infected Atlantic salmon farms in Scotland
Authors: Gregory A , Munro L A , Wallace I S , Bain N , Raynard R S
Published: September 2007

Infectious pancreatic necrosis virus (IPNV) has been isolated from mussels, sediment and surface water in the vicinity of clinically infected salmon farms, at shore bases supplying the farms and for several hundred metres distance from farms in the direction of current flow. There was evidence of decreasing prevalence of IPNV in mussels from Shetland once IPN outbreaks subsided, indicating they are an unlikely source of re‐infection on farms. There was little evidence of persistence in the environment, although conclusions were complicated by the presence of IPNV on neighbouring farms 1 year after the outbreak.
Obesity‐induced inflammation: a metabolic dialogue in the language of inflammation
Authors: Ferrante A. W.
Published: September 2007

Obesity induces an inflammation state that is implicated in many clinically important complications, including insulin resistance, diabetes, atherosclerosis and non‐alcoholic fatty liver disease. Although the cause and the molecular participants in this process remain incompletely defined, adipose tissue has a central role. Obesity‐induced production of pro‐inflammatory molecules, typified by TNF‐α was recognized more than a dozen years ago, and since then more than two dozen other pro‐inflammatory molecules induced by obesity have been identified. More recently a critical role for immune cells, specifically mononuclear phagocytes, in generating the obesity‐induced inflammation has been identified. Defining the molecular and cellular components of obesity‐induced inflammation offers the potential of identifying therapeutic targets that can ameliorate the complications associated with obesity.
Increased Caloric Intake on a Fat‐Rich Diet: Role of Ovarian Steroids and Galanin in the Medial Preoptic and Paraventricular Nuclei and Anterior Pituitary of Female Rats
Authors: Leibowitz S. F. , Akabayashi A. , Wang J. , Alexander J. T. , Dourmashkin J. T. , Chang G‐Q.
Published: September 2007

Previous studies in male rats have demonstrated that the orexigenic peptide galanin (GAL), in neurones of the anterior parvocellular region of the paraventricular nucleus (aPVN) projecting to the median eminence (ME), is stimulated by consumption of a high‐fat diet and may have a role in the hyperphagia induced by fat. In addition to confirming this relationship in female rats and distinguishing the aPVN‐ME from other hypothalamic areas, the present study identified two additional extra‐hypothalamic sites where GAL is stimulated by dietary fat in females but not males. These sites were the medial preoptic nucleus (MPN), located immediately rostral to the aPVN, and the anterior pituitary (AP). The involvement of ovarian steroids, oestradiol (E2) and progesterone (PROG), in this phenomenon was suggested by an observed increase in circulating levels of these hormones and GAL in MPN and AP with fat consumption and an attenuation of this effect on GAL in ovariectomised (OVX) rats. Furthermore, in the same four areas affected by dietary fat, levels of GAL mRNA and peptide immunoreactivity were stimulated by E2 and further by PROG replacement in E2‐primed OVX rats and were higher in females compared to males. Because both GAL and PROG stimulate feeding, their increase on a fat‐rich diet may have functional consequences in females, possibly contributing to the increased caloric intake induced by dietary fat. This is supported by the findings that PROG administration in E2‐primed OVX rats reverses the inhibitory effect of E2 on total caloric intake while increasing voluntary fat ingestion, and that female rats with higher GAL exhibit increased preference for fat compared to males. Thus, ovarian steroids may function together with GAL in a neurocircuit, involving the MPN, aPVN, ME and AP, which coordinate feeding behaviour with reproductive function to promote consumption of a fat‐rich diet at times of increased energy demand.
Effects of Organisational Oestradiol on Adult Immunoreactive Oestrogen Receptors (α and β) in the Male Mouse Brain
Authors: Kudwa A. E. , Harada N. , Honda S.‐I. , Rissman E. F.
Published: September 2007

Steroid hormones act on developing neural circuits that regulate the hypothalamic‐pituitary‐gonadal axis and are involved in hormone‐sensitive behaviours. To test the hypothesis that developmental exposure to oestradiol (E2) organises the quantity of adult oestrogen receptors (ERα and ERβ), we used male mice with a targeted mutation of the aromatase enzyme gene (ArKO) and their wild‐type (WT) littermates. These mice are unable to aromatise testosterone to E2, but still express both ERα and β. To evaluate adult responsiveness to E2, gonadectomised males were implanted with Silastic capsules containing E2, or an empty implant, 5 days prior to sacrifice. Immunoreactivity for ERα and ERβ was quantified in the caudal ventromedial nucleus (VMN) and the medial preoptic area (POA). Regardless of genotype, adult treatment with E2 reduced ERα‐immunoreactive (ir) and ERβ‐ir cell numbers in the POA, as well as ERβ‐ir, but not ERα‐ir, cell numbers in the VMN. Genotype, and thus endogenous exposure to E2, produced opposite effects on ER expression in the two brain areas. In the VMN, ArKO males had more ERα‐ir and ERβ‐ir cells than did WT males. In the POA, ArKO males had fewer ERα‐ir and ERβ‐ir cells than did WT males. Thus, numbers of immunoreactive neurones containing both ERs in the adult ArKO male were enhanced in the POA, but decreased in the VMN, and most likely these patterns were established during the developmental critical period. Furthermore, although both ERα and β‐ir cell numbers are altered by the disruption of the aromatase gene, ERβ is altered in a more robust and region‐specific manner.
Reproductive Experience and Expression of Dopamine D2 Receptor mRNA: A Possible Mechanism for Reduced Prolactin Secretion in Primiparous Rats
Authors: Byrnes E. M. , Bridges R. S.
Published: September 2007

Reproductive experience (i.e. pregnancy and lactation) leads to reduced levels of circulating prolactin in both women and rats. Stimulation of prolactin secretion by dopamine antagonists is also blunted following reproductive experience in both species. Whereas a parity‐induced reduction in haloperidol‐stimulated prolactin secretion is evident in ovariectomised rats, it is unknown whether a similar attenuation of prolactin secretion is present in reproductively experienced, cycling pro‐oestrous rats. The present study examined this possibility. Moreover, to determine possible mechanisms involved in parity‐mediated changes in prolactin secretion, both dopamine utilisation within the arcuate nucleus/median eminence and expression of dopamine D2 receptor mRNA (short and long forms) in the anterior pituitary were measured across the afternoon of pro‐oestrous in reproductively experience and inexperienced females. Prolactin secretion was lower on the afternoon of pro‐oestrous in primiparous females compared to age‐matched, nulliparous controls. In addition, haloperidol‐stimulated prolactin secretion was reduced in ovariectomised, reproductively experienced females. Although no differences in dopamine utilisation were observed as a function of reproductive experience, parity did affect the expression of both forms of D2 receptor mRNA in the anterior pituitary. Compared with nulliparous controls, primiparous females had increased D2 long mRNA expression at 12.00 h on pro‐oestrous as well as increased D2 short mRNA expression at 14.00 h. Because the ratio of D2 long/D2 short can significantly effect lactotroph proliferation and prolactin secretion, a shift in relative expression of the two D2 receptor isoforms within the anterior pituitary of parous females may help account for the reduction in prolactin secretion that occurs following reproductive experience.
Neuroendocrine Regulation of Fluid and Electrolyte Balance By Ovarian Steroids: Contributions From Central Oestrogen Receptors
Authors: Somponpun S. J.
Published: September 2007

Like other hormonally mediated mechanisms, maintenance of body fluid osmolality requires integrated responses from multiple signals at various tissue locales, a large number of which are open to modulation by circulating endocrine factors including the ovarian steroid, oestrogens (E2). However, the precise mechanism and the site of action of E2 in regulating fluid osmolality are not properly understood. More importantly, the biological significance of this action is not clear and the physiological circumstances in which this modulation is engaged remain incomplete. The demonstration of oestrogen receptors (ER) in neural tissues that bear no direct relation to reproduction led us to examine and characterise the expression of ER in brain nuclei that are critical for the maintenance of fluid osmolality. In the rat, ERβ is prominently expressed in the vasopressin magnocellular neuroendocrine cells of the hypothalamus, whereas ERα is localised extensively in the sensory circumventricular organ neurones in the basal forebrain. These nuclei are the primary brain sites that are engaged in defense of fluid perturbation, thus providing a neuroendocrine basis for oestrogenic influence on body fluid regulation. Plasticity in receptor expression that accompanies fluid disturbances at these central loci suggests the functional importance of the receptors and implicates E2 as one of the fluid regulating hormones in water homeostasis.
Oestrogen and Progesterone Reduce Lipopolysaccharide‐Induced Expression of Tumour Necrosis Factor‐α and Interleukin‐18 in Midbrain Astrocytes
Authors: Kipp M. , Karakaya S. , Johann S. , Kampmann E. , Mey J. , Beyer C.
Published: September 2007

Besides microglia, astrocytes exert an important regulatory function in the initiation and control of neuro‐inflammatory processes in the central nervous system. Clinical and experimental data suggest that sex steroids are neuroprotective and that neurological/neurodegenerative disorders display sex‐specific characteristics. Astroglia is known to respond to toxic stimuli by secretion of distinct pro‐inflammatory/apoptotic cytokines. In the present study, we investigated the influence of oestrogen and progesterone on the expression of the cytokines tumour necrosis factor (TNF)‐α and interleukin (IL)‐18 in primary astrocytes obtained from neonatal mouse midbrain and cerebral cortex after the stimulation with lipopolysaccharides (LPS). LPS strongly induced the expression of TNF‐α in astrocytes from both brain regions and IL‐18 in those from midbrain. Oestrogen significantly attenuated LPS‐induced TNF‐α expression in the midbrain glia but not in the cortex glia. Combined treatment with oestrogen and progesterone together diminished LPS‐induced IL‐18 expression in the midbrain completely. Both steroid effects could be specifically antagonised by the steroid hormone receptor antagonists ICI 182 780 and mifepristone. We conclude that neuroprotective oestrogen and progesterone effects in the midbrain might be in part the consequence of a reduced pro‐inflammatory response of astroglia.
Changes of Expression of Genes Related to the Activity of the Gonadotrophin‐Releasing Hormone Pulse Generator in Young Versus Middle‐Aged Male Rats
Authors: Böttner M. , Leonhardt S. , Wuttke W. , Jarry H.
Published: September 2007

In females, it is well established that changes in the expression of neurotransmitters and peptides regulating the activity of the gonadotrophin‐releasing hormone (GnRH) pulse generator are altered during ageing. By contrast, little is known about whether those age‐related changes also occur in males. Therefore, we designed an animal study with orchidectomised young and middle‐aged male rats to investigate changes in luteinising hormone (LH) secretion profiles and changes in the mRNA expression of genes regulating the activity of the GnRH pulse generator. Our results demonstrate that middle‐aged rats exhibit lower serum LH levels and relatively fewer LH pulses with attenuated amplitude compared to young animals. Furthermore, upon ageing, GnRH mRNA expression is up‐regulated in the preoptic area and the septum where GnRH neurones reside. Analysis of mRNA levels of glutamate decarboxylase (GAD) enzymes revealed that GAD65 and GAD67 mRNA expression increased in the mediobasal hypothalamus (MBH) and that GAD67 mRNA levels decreased in the suprachiasmatic nucleus. In addition, we observed an age‐related increase of oestrogen receptor (ER)α mRNA in the MBH, and both ERα and ERβ mRNA expression was up‐regulated in the pituitary of middle‐aged rats compared to young animals. Taken together, our data support the existence of a male ‘andropause’ that is, like the menopause in females, accompanied by changes in neurotransmitter and hormone receptor expression that are involved in regulating the function of the GnRH pulse generator.
Expression of Ovarian Steroid Hormone Receptors in Tuberoinfundibular Dopaminergic Neurones During Pregnancy and Lactation
Authors: Steyn F. J. , Anderson G. M. , Grattan D. R.
Published: September 2007

During late‐pregnancy, tuberoinfundibular dopaminergic (TIDA) neurones, a critical component of the negative‐feedback loop regulating prolactin secretion, become unresponsive to the stimulatory effects of prolactin. The change in TIDA responsiveness to prolactin at this time results in a decrease in dopamine secretion and a prolactin surge. As the onset of parturition and the antepartum prolactin surge depend on the withdrawal of progesterone in the presence of oestrogen, it is likely that ovarian steroid hormones mediate this change in TIDA responsiveness. To determine whether ovarian steroids can directly modulate TIDA activity, and whether changes of receptor numbers might contribute to overall steroid‐regulation of these neurones, we investigated the level of oestrogen receptor alpha (ERα) and progesterone receptor (PR) expression within TIDA neurones during pregnancy and lactation. Animals were sacrificed on dioestrous, days 12, 19 and 21 of pregnancy and day 5 of lactation, and the proportion of TIDA neurones expressing ERα or PR, as well as the total number of PR expressing cells within the arcuate nucleus, was determined. Approximately 75% and 55% of tyrosine hydroxylase neurones expressed ERα and PR, respectively. Levels of steroid receptor expression within TIDA neurones remained fairly constant, except for an increase in ERα on days 12 and 19 of pregnancy compared to dioestrous and lactation day 5. The presence of steroid receptors on TIDA neurones during pregnancy and lactation supports the concept of a direct effect of steroid hormones on these neurones at this time. Thus, steroid hormones may directly act on TIDA neurones to regulate maternal prolactin secretion. The relatively stable level of expression during late pregnancy suggests that a shift in steroid receptor expression during late pregnancy does not contribute to the change in TIDA responsiveness to prolactin at this time.
Androgen Receptor Expression in the Levator Ani Muscle of Male Mice
Authors: Johansen J. A. , Breedlove S. M. , Jordan C. L.
Published: September 2007

The spinal nucleus of the bulbocavernosus (SNB) is a sexually dimorphic group of motoneurones that innervates the bulbocavernosus (BC) and levator ani (LA), skeletal muscles that attach to the base of the penis. In many species, including mice, rats and hamsters, the LA and BC have been found to be highly responsive to androgen and, in rats, these muscles mediate several effects of androgen on the SNB system. However, characterising the SNB system in mice is important because of the availability of genetic models in this species. In the present study, we examined AR expression in skeletal muscles of C57/BlJ6 adult male mice using immunoblotting and immunocytochemistry, comparing the BC/LA to the androgen‐unresponsive extensor digitorum longus (EDL). We found similar differences in AR expression for these muscles in the mouse as previously reported for rats. In mice, the BC/LA contains more AR protein than does the EDL. At the cellular level, the LA contains a higher percentage of AR positive myonuclei and fibroblasts than does the EDL. Finally, AR expression is enriched at the neuromuscular junction of mouse LA fibres. The increased expression of AR in the LA compared to the EDL in both muscle fibres and fibroblasts indicates that each cell type may critically mediate androgen action on the SNB system in mice.
Mapping Brain c‐Fos Immunoreactivity after Insulin‐Induced Voluntary Lard Intake: Insulin‐ and Lard‐Associated Patterns
Authors: Warne J. P. , Horneman H. F. , Ginsberg A. B. , Pecoraro N. C. , Foster M. T. , Akana S. F. , Dallman M. F.
Published: September 2007

In addition to the inhibitory role of central insulin on food intake, insulin also acts to promote lard intake. We investigated the neural pathways involved in this facet of insulin action. Insulin or saline was infused into either the superior mesenteric or right external jugular veins of streptozotocin‐diabetic rodents with elevated steady‐state circulating corticosterone concentrations. After postsurgical recovery, rats were offered the choice of chow or lard to eat. Irrespective of the site of venous infusion, insulin increased lard and decreased chow intake. After 4 days, lard was removed for 8 h. On return for 1 h, only insulin infused into the superior mesenteric vein resulted in lard intake. This facilitated distinction between the effects of circulating insulin concentrations (similar in the two insulin‐infused groups) and lard ingestion on the patterns of c‐Fos+ cells in the brain, termed insulin‐ and lard‐associated patterns, respectively. Insulin‐associated changes in c‐Fos+ cell numbers were evident in the arcuate nucleus, bed nucleus of the stria terminalis and substantia nigra pars compacta, concomitant with elevated leptin levels and reduced chow intake. Lard‐associated changes in c‐Fos+ cell numbers were observed in the nucleus of the tractus solitarius, lateral parabrachial nucleus, central nucleus of the amygdala, ventral tegmental area, nucleus accumbens shell and the prefrontal cortex, and were associated with lower levels of triglycerides and free fatty acids. The anterior paraventricular thalamic nucleus exhibited both patterns. These data collectively fit into a framework for food intake and reward and provide targets for pharmacological manipulation to influence the choice of food intake.
Chronic Stress and Neural Function: Accounting for Sex and Age
Authors: Luine V. N. , Beck K. D. , Bowman R. E. , Frankfurt M. , MacLusky N. J.
Published: September 2007

Cognitive responses to stress follow the temporally dependent pattern originally established by Selye (1) wherein short‐term stressors elicit adaptive responses whereas continued stress (chronic) results in maladaptive changes – deleterious effects on physiological systems and impaired cognition. However, this pattern for cognitive effects appears to apply to only half the population (males) and, more specifically, to young, adult males. Females show different cognitive responses to stress. In contrast to impaired cognition in males after chronic stress, female rodents show enhanced performance on the same memory tasks after the same stress. Not only cognition, but anxiety, shows sex‐dependent changes following chronic stress – stress is anxiolytic in males and anxiogenic in females. Moreover, behavioral responses to chronic stress are different in developing as well as aging subjects (both sexes) as compared to adults. In aged rats, chronic stress enhances recognition memory in both sexes, does not alter spatial memory, and anxiety effects are opposite to young adults. When pregnant dams are exposed to chronic stress, at adulthood the offspring display yet different consequences of stress on anxiety and cognition, and, in contrast to adulthood when the behavioral effects of stress are reversible, prenatal stress effects appear enduring. Changing levels of estradiol in the sexes over the lifespan appear to contribute to the differences in response to stress. Thus, theories of stress dependent moduations in CNS function – developed solely in male models, focused on peripheral physiological processes and tested in adults – may require revision when applied to a more diverse population (age‐ and sex‐wise) at least in relation to the neural functions of codnition and anxiety. Moreover, these results suggest that other stressors and neural functions should be investigated to determine whether age, sex and gonadal hormones also have an impact.
The value of infrared thermography for research on mammals: previous applications and future directions
Authors: MCCAFFERTY DOMINIC J.
Published: September 2007

Infrared thermography (IRT) involves the precise measurement of infrared radiation which allows surface temperature to be determined according to simple physical laws. This review describes previous applications of IRT in studies of thermal physiology, veterinary diagnosis of disease or injury and population surveys on domestic and wild mammals.

IRT is a useful technique because it is non‐invasive and measurements can be made at distances of <1 m to examine specific sites of heat loss to >1000 m to count large mammals. Detailed measurements of surface temperature variation can be made where large numbers of temperature sensors would otherwise be required and where conventional solid sensors can give false readings on mammal coats. Studies need to take into account sources of error due to variation in emissivity, evaporative cooling and radiative heating of the coat.

Recent advances in thermal imaging technology have produced lightweight, portable systems that store digital images with high temperature and spatial resolution. For these reasons, there are many further opportunities for IRT in studies of captive and wild mammals.
Genetic isolation and cryptic variation within the Lycaena xanthoides species group (Lepidoptera: Lycaenidae)
Authors: OLIVER JEFFREY C. , SHAPIRO ARTHUR M.
Published: September 2007

Species exist as biological entities with patterns of discontinuous phenotypic variation. However, the distinctness of taxa is called into question when morphological intermediates exist in areas of sympatry, reflecting either gene flow among variants of a species or hybridization between different species. Studying the partitioning of genetic variation provides a means to discern between the two possibilities. We used genetic and morphometric approaches to investigate the degree of isolation among the three members of the Lycaena xanthoides species group. Lycaena xanthoides, L. editha, and L. dione are predominantly allopatric and have been treated both as three separate species and as a single polytypic species. Using 618 bp of the mitochondrial gene COII, we found little phylogenetic resolution, but significant among‐taxa genetic variance partitioning. Divergence among these taxa has been relatively recent, as evidenced by relatively low pairwise sequence divergence. Also, the existence of two well‐supported clades within L. xanthoides sensu stricto, concordant with the Transverse Ranges of southern California, indicates divergence within this taxon, and a possible cryptic species. Significant morphological differentiation between L. editha and L. xanthoides supports the hypothesis that these taxa represent separate gene pools. Populations occurring in a narrow zone where the two species’ ranges approach are characterized by intermediate morphology, suggesting incomplete morphological divergence or recent hybridization. These findings highlight the utility of genetic data in inferring species boundaries and the identification of cryptic lineages.
Shared quantitative trait loci underlying the genetic correlation between continuous traits
Authors: GARDNER KYLE M. , LATTA ROBERT G.
Published: September 2007

We review genetic correlations among quantitative traits in light of their underlying quantitative trait loci (QTL). We derive an expectation of genetic correlation from the effects of underlying loci and test whether published genetic correlations can be explained by the QTL underlying the traits. While genetically correlated traits shared more QTL (33%) on average than uncorrelated traits (11%), the actual number of shared QTL shared was small. QTL usually predicted the sign of the correlation with good accuracy, but the quantitative prediction was poor. Approximately 25% of trait pairs in the data set had at least one QTL with antagonistic effects. Yet a significant minority (20%) of such trait pairs have net positive genetic correlations due to such antagonistic QTL ‘hidden’ within positive genetic correlations. We review the evidence on whether shared QTL represent single pleiotropic loci or closely linked monotropic genes, and argue that strict pleiotropy can be viewed as one end of a continuum of recombination rates where r = 0. QTL studies of genetic correlation will likely be insufficient to predict evolutionary trajectories over long time spans in large panmictic populations, but will provide important insights into the trade‐offs involved in population and species divergence.
Restrictive mating by females on black grouse leks
Authors: LEBIGRE C. , ALATALO R. V. , SIITARI H. , PARRI S.
Published: September 2007

In bird species with pair bonds, extra‐pair matings could allow females to choose genetically superior males. This is not needed in lekking species because female choice is not constrained by pairing opportunities. However, polyandry has been reported in most lekking species studied so far. Using 12 microsatellite loci, we determined the paternity of 135 broods of black grouse sampled between 2001 and 2005 (970 hatchlings and 811 adult birds genotyped). The paternity assignments were combined to lek observations to investigate the mating behaviour of black grouse females. About 10% of the matings seemed to take place with males displaying solitarily. Forty per cent of the copulations between males displaying on the studied leks and radio‐tagged females were not recorded. This was due to difficulties in identifying the females and because our observations did not cover all the possible time for matings. However, females of the undetected copulations had chosen males that were already known to be successful on the leks. There was a strong consistency between the observations and true paternity, even when the copulation was disturbed by a neighbouring male. Multiple mating and multiple paternities were rare. We can now confidently ascertain that most females mate only once with one male for the whole clutch. This mating behaviour requires that a single insemination is sufficient to fertilize a clutch and that females can determine whether the sperm has been successfully transferred. Grouse Tetraoninae with many lekking species may be the only bird taxon that has evolved these traits.
Hybridization in postglacial marine habitats
Authors: RIGINOS CYNTHIA , CUNNINGHAM CLIFFORD W.
Published: September 2007

Within the last few million years, repeated invasions from the North Pacific have brought evolutionarily divergent lineages ofMacoma balthicaclams into contact in the marginal and inland seas of northern Europe (Strelkovet al. 2007). These divergentM. balthicalineages now co‐occur and hybridize extensively, blurring the distinction between the lineages and with some populations best described as ‘hybrid swarms’. This scenario matches the prediction that hybridization between distinct genetic entities can generate evolutionary novelty, particularly in new environments where hybrid fitness is equal to or exceeds parental types (Arnold 1997; Seehausen 2004).
Molecular and quantitative trait variation across the native range of the invasive species Hypericum canariense: evidence for ancient patterns of colonization via pre‐adaptation?
Authors: DLUGOSCH K. M. , PARKER I. M.
Published: September 2007

To understand the success of invasive species, it is important to know whether colonization events are facilitated by adaptive evolution or are limited to sites where a species is pre‐adapted to thrive. Studies of the ancient colonization patterns of an invader in its native range provide an opportunity to examine its natural history of adaptation and colonization. This study uses molecular (internal transcribed spacer sequence and amplified fragment length polymorphism) and common garden approaches to assess the ancient patterns of establishment and quantitative trait evolution in the invasive shrub Hypericum canariense. This species has an unusually small and discrete native range in the Canary Islands. Our data reveal two genetic varieties with divergent life histories and different colonization patterns across the islands. Although molecular divergence within each variety is large (pairwise FST from 0.18 to 0.32 between islands) and nearly as great as divergence between them, life‐history traits show striking uniformity within varieties. The discrepancy between molecular and life‐history trait divergence points to the action of stabilizing selection within varieties and the influence of pre‐adaptation on patterns of colonization. The colonization history of H. canariense reflects how the relationship between selective environments in founding and source populations can dictate establishment by particular lineages and their subsequent evolutionary stasis or change.
Genetic response to rapid climate change: it's seasonal timing that matters
Authors: BRADSHAW W. E. , HOLZAPFEL C. M.
Published: September 2007

The primary nonbiological result of recent rapid climate change is warming winter temperatures, particularly at northern latitudes, leading to longer growing seasons and new seasonal exigencies and opportunities. Biological responses reflect selection due to the earlier arrival of spring, the later arrival of fall, or the increasing length of the growing season. Animals from rotifers to rodents use the high reliability of day length to time the seasonal transitions in their life histories that are crucial to fitness in temperate and polar environments: when to begin developing in the spring, when to reproduce, when to enter dormancy or when to migrate, thereby exploiting favourable temperatures and avoiding unfavourable temperatures. In documented cases of evolutionary (genetic) response to recent, rapid climate change, the role of day length (photoperiodism) ranges from causal to inhibitory; in no case has there been demonstrated a genetic shift in thermal optima or thermal tolerance. More effort should be made to explore the role of photoperiodism in genetic responses to climate change and to rule out the role of photoperiod in the timing of seasonal life histories before thermal adaptation is assumed to be the major evolutionary response to climate change.
The origins of weedy rice
Authors: KANE NOLAN C. , BAACK ERIC J.
Published: September 2007

Where do weeds come from? How do they evolve from nonweedy ancestors? In this issue of Molecular Ecology, Londo and Schaal examine the origin of weedy rice (Oryza sativa) populations in the USA. Analysing nuclear DNA sequence and microsatellite data, they show the importance of parallel evolution, hybridization, gene flow, and migration in the evolution of these weeds.
RrgA is a pilus‐associated adhesin in Streptococcus pneumoniae
Authors: Nelson A. L. , Ries J. , Bagnoli F. , Dahlberg S. , Fälker S. , Rounioja S. , Tschöp J. , Morfeldt E. , Ferlenghi I. , Hilleringmann M. , Holden D. W. , Rappuoli R. , Normark S. , Barocchi M. A. , Henriques‐Normark B.
Published: September 2007

Adherence to host cells is important in microbial colonization of a mucosal surface, and Streptococcus pneumoniae adherence was significantly enhanced by expression of an extracellular pilus composed of three subunits, RrgA, RrgB and RrgC. We sought to determine which subunit(s) confers adherence. Bacteria deficient in RrgA are significantly less adherent than wild‐type organisms, while overexpression of RrgA enhances adherence. Recombinant monomeric RrgA binds to respiratory cells, as does RrgC with less affinity, and pre‐incubation of epithelial cells with RrgA reduces adherence of wild‐type piliated pneumococci. Non‐adherent RrgA‐negative, RrgB‐ and RrgC‐positive organisms produce pili, suggesting that pilus‐mediated adherence is due to expression of RrgA, rather than the pilus backbone itself. In contrast, RrgA‐positive strains with disrupted rrgB and rrgC genes exhibit wild‐type adherence despite failure to produce pili by Western blot or immunoelectron microscopy. The density of bacteria colonizing the upper respiratory tract of mice inoculated with piliated RrgA‐negative pneumococci was significantly less compared with wild‐type; in contrast, non‐piliated pneumococci expressing non‐polymeric RrgA had similar numbers of bacteria in the nasopharynx as piliated wild‐type bacteria. These data suggest that RrgA is central in pilus‐mediated adherence and disease, even in the absence of polymeric pilus production.
Mechanism of hcnA mRNA recognition in the Gac/Rsm signal transduction pathway of Pseudomonas fluorescens
Authors: Lapouge Karine , Sineva Elena , Lindell Magnus , Starke Katja , Baker Carol S. , Babitzke Paul , Haas Dieter
Published: September 2007

In the plant‐beneficial bacterium Pseudomonas fluorescens CHA0, the expression of antifungal exoproducts is controlled by the GacS/GacA two‐component system. Two RNA binding proteins (RsmA, RsmE) ensure effective translational repression of exoproduct mRNAs. At high cell population densities, GacA induces three small RNAs (RsmX, RsmY, RsmZ) which sequester both RsmA and RsmE, thereby relieving translational repression. Here we systematically analyse the features that allow the RNA binding proteins to interact strongly with the 5′ untranslated leader mRNA of the P. fluorescens hcnA gene (encoding hydrogen cyanide synthase subunit A). We obtained evidence for three major RsmA/RsmE recognition elements in the hcnA leader, based on directed mutagenesis, RsmE footprints and toeprints, and in vivo expression data. Two recognition elements were found in two stem‐loop structures whose existence in the 5′ leader region was confirmed by lead(II) cleavage analysis. The third recognition element, which overlapped the hcnA Shine–Dalgarno sequence, was postulated to adopt either an open conformation, which would favour ribosome binding, or a stem‐loop structure, which may form upon interaction with RsmA/RsmE and would inhibit access of ribosomes. Effective control of hcnA expression by the Gac/Rsm system appears to result from the combination of the three appropriately spaced recognition elements.
Pho85, a multifunctional cyclin‐dependent protein kinase in budding yeast
Authors: Huang Dongqing , Friesen Helena , Andrews Brenda
Published: September 2007

Pho85 is a multifunctional cyclin‐dependent kinase (Cdk) inSaccharomyces cerevisiaethat has emerged as an important model for the role of Cdks in both cell cycle control and other processes. Pho85 is targeted to its substrates by 10 different cyclins or Pcls. Three of these Pcls have specific roles in G1 phase of the cell cycle, both in regulating G1‐specific gene expression and in controlling polarized growth. Many known substrates of the G1 forms of Pho85 are also phosphorylated by the homologous Cdk Cln–Cdc28, suggesting parallel or overlapping roles. Most of the remaining Pcls function in signalling: Pho85 is generally active when environmental conditions are satisfactory, phosphorylating proteins involved in transcription and other regulatory events to keep the stress response and inappropriate activities turned off. Recently, genetic screens for synthetic lethality and synthetic dosage lethality, and proteomic screens forin vitroPho85 substrates, have revealed more details about how Pho85 functions to regulate a variety of cellular processes.
Microarray analysis of Mu transposition in Salmonella enterica, serovar Typhimurium: transposon exclusion by high‐density DNA binding proteins
Authors: Manna Dipankar , Porwollik Steffen , McClelland Michael , Tan Ruimin , Higgins N. Patrick
Published: September 2007

All organisms contain transposons with the potential to disrupt and rearrange genes. Despite the presence of these destabilizing sequences, some genomes show remarkable stability over evolutionary time. Do bacteria defend the genome against disruption by transposons? Phage Mu replicates by transposition and virtually all genes are potential insertion targets. To test whether bacteria limit Mu transposition to specific parts of the chromosome, DNA arrays of Salmonella enterica were used to quantitatively measure target site preference and compare the data with Escherichia coli. Essential genes were as susceptible to transposon disruption as non‐essential ones in both organisms, but the correlation of transposition hot spots among homologous genes was poor. Genes in highly transcribed operons were insulated from transposon mutagenesis in both organisms. A 10 kb cold spot on the pSLT plasmid was near parS, a site to which the ParB protein binds and spreads along DNA. Deleting ParB erased the plasmid cold spot, and an ectopic parS site placed in the Salmonella chromosome created a new cold spot in the presence of ParB. Our data show that competition between cellular proteins and transposition proteins on plasmids and the chromosome is a dominant factor controlling the genetic footprint of transposons in living cells.
Gradual activation of the response regulator DegU controls serial expression of genes for flagellum formation and biofilm formation in Bacillus subtilis
Authors: Kobayashi Kazuo
Published: September 2007

In natural environments, bacteria fluctuate between growth as motile cells and growth as sessile, biofilm‐forming cells. However, what controls the transition between these two‐growth modes in Bacillus subtilis is not well understood yet. The degU mutation prevents both flagellum formation and biofilm formation, suggesting that one of the transition mechanisms may underlie regulation of the DegU activity. The expression profiles of DegU‐regulated genes differed; flagellar genes and several unknown genes were expressed during the exponential phase, whereas other genes were induced in the stationary phase. The degS mutation did not affect transcription of the flgB‐sigD operon, but reduced transcription of σD‐dependent flagellar genes, degU and other DegU‐regulated genes. In addition, the degQ mutation did not affect transcription of flagellar genes but reduce transcription of other DegU‐regulated genes. Purified DegQ protein stimulated phosphotransfer from phospho‐DegS to DegU in vitro. Moreover, DegU binds the promoter region of flgB with a high affinity, whereas DegU binds to the promoter regions of other DegU‐regulated genes with a low affinity and in a DegS‐dependent manner. Taken together, we propose that a gradual increase in DegU and phospho‐DegU levels induces a transition from growth as motile cells to growth as sessile, biofilm‐forming cells.