bluuebunny/crossref_metadata_2025 huggingface dataset:
Basal and apical synapses of CA1 pyramidal cells employ different LTP induction mechanisms.
Authors: Haley J E , Schaible E , Pavlidis P , Murdock A , Madison D V
Published: June 2007

Nitric oxide (NO) production has been widely reported to be required for the induction of long-term potentiation (LTP) in hippocampal CA1 cells. Of the two constitutive isoforms of NO synthase, the endothelial form (eNOS) has been implicated in the induction of LTP in these cells. The distribution of eNOS within CA1 cells is not uniform, however, being present in the cell bodies and apical dendrites but absent from the basal dendrites. Using extracellular and intracellular recording techniques, we demonstrate that LTP induction in stratum radiatum synapses (onto apical dendrites) is dependent on NO production, being attenuated by pretreatment with a NOS inhibitor. LTP induced in stratum oriens synapses (onto basal dendrites) is, however, resistant to NOS inhibitors. Both forms of LTP require the activation of N-methyl-D-aspartate (NMDA) receptors because induction of LTP in both stratum radiatum and stratum oriens is blocked by AP5. Thus, it appears that synapses onto apical and basal dendrites of CA1 cells use different cellular mechanisms of LTP induction.
Temporally graded retrograde amnesia following separate and combined lesions of the perirhinal cortex and fornix in the rat.
Authors: Wiig K A , Cooper L N , Bear M F
Published: June 2007

The involvement of the perirhinal cortex and the fornix in retrograde and anterograde amnesia in the rat was investigated in this experiment. Male Sprague-Dawley rats were trained on a series of five visual discrimination problems at distinct time intervals prior to receiving bilateral, electrolytic lesions of the perirhinal cortex or the fornix, combined lesions of both these structures, or sham operations. Following recovery from surgery, rats were retested on the preoperatively learned discrimination problems, as well as learning a new discrimination and discrimination reversal. Results indicated that all animals with lesions exhibited temporally graded retrograde amnesia, whereby memories acquired in the recent past (1-3 weeks) were impaired, and memories acquired in the remote past (6-8 weeks) were spared. There was no difference in the magnitude of retrograde amnesia between the three lesion groups. Animals in the perirhinal, fornix, and combined lesion groups were able to learn a new discrimination problem at a rate comparable to control rats; however, the animals with lesions were impaired at learning the discrimination reversal. The perirhinal, fornix, and combined lesion animals also exhibited a significantly faster forgetting rate over a 2-week retention interval than control rats. These results suggest that medial temporal structures including the perirhinal cortex and the fornix are involved in the consolidation of mnemonic information and that their involvement in this process occurs over a discrete period of time.
Suppression of c-fos induction in rat brain impairs retention of a brightness discrimination reaction.
Authors: Grimm R , Schicknick H , Riede I , Gundelfinger E D , Herdegen T , Zuschratter W , Tischmeyer W
Published: June 2007

Recently, the induction of transcription factor-encoding immediate-early genes such as c-fos was observed in distinct brain regions of rats trained to acquire a footshock-motivated brightness discrimination in a Y-maze. The functional relevance of inducible transcription factors for learning and memory formation is, however, not clear. To address this question in the present study, we have used a synthetic antisense phosphorothioate oligodeoxynucleotide to suppress in vivo the expression of c-fos in rat brain. Intrahippocampal application of the oligodeoxynucleotide 10 hr and 2 hr before starting a brightness discrimination training drastically reduced the induction of c-Fos immunoreactivity normally observed in limbic and cortical areas after the training session. Acquisition of the discrimination reaction was not affected by this treatment. In a relearning test 24 hr after the first training, retention of the discrimination reaction was specifically impaired compared with rats pretreated with control oligodeoxynucleotide or saline. Our findings are consistent with the hypothesis that the inducible transcription factor c-Fos is involved in processes underlying the formation of long-term memory.
The effects of reversible inactivation of the red nucleus on learning-related and auditory-evoked unit activity in the pontine nuclei of classically conditioned rabbits.
Authors: Cartford M C , Gohl E B , Singson M , Lavond D G
Published: June 2007

The pontine nuclei carry auditory conditioned stimulus information to the cerebellum during classical conditioning of the nictitating membrane response in rabbits. In well-trained animals learning-related as well as stimulus-evoked unit activity can be recorded throughout the pontine nuclei but particularly in the lateral and dorsolateral pons. Recent work in our laboratory has provided evidence that the learning-related unit activity in the pons is dependent on the interpositus nucleus and that the pons is not a site of essential plasticity for the learned response. In the present study we considered the question of whether learning-related unit activity might be projected from the interpositus nucleus to the pons through the red nucleus, a primary output target of the interpositus and a structure known to be essential for expression of the learned response. Multiple unit recordings were taken from lateral and dorsolateral pontine locations in well-trained rabbits before and during cooling of the red nucleus. Analysis of pooled data for all recording locations within the lateral and dorsolateral pons indicated that reversible inactivation of red nucleus abolished both stimulus-evoked and learning-related unit activity. However, we also found discrete recording locations where stimulus-evoked and learning-related unit activity were attenuated but not abolished by red nucleus cooling.
Reversible inactivation of the cerebellar interpositus nucleus completely prevents acquisition of the classically conditioned eye-blink response.
Authors: Krupa D J , Thompson R F
Published: June 2007

Numerous studies from several laboratories report that temporary inactivation of the cerebellar interpositus nucleus and regions of overlying cortex during eye-blink conditioning completely prevents acquisition of the conditioned eye-blink response (CR) without affecting the ability to learn the CR in subsequent training without inactivation. Recently, these results have been challenged by the suggestion that learning was not completely blocked in these studies. Instead, it has been suggested that low levels of responses on test sessions might represent a retarded form of learning caused by drug effects on cerebellar cortex. The present study was designed to address this issue directly. Very low doses of muscimol were used to selectively inactivate the interpositus nucleus of rabbits during five conditioning sessions. Animals performed no significant levels of CRs during those sessions. Training was continued four more sessions without any inactivations to test whether any learning had occurred during the previous five sessions. Detailed analysis of responses during session six revealed that learning was completely blocked by the low doses of muscimol infused into the interpositus during the first five sessions. Animals subsequently acquired the CR normally. These results confirm and extend the original findings that appropriate lesions (either temporary or permanent) of the interpositus nucleus completely prevent acquisition of the conditioned eye-blink response. Other issues regarding reversible inactivation studies are also discussed.
Effect of varying the intensity and train frequency of forelimb and cerebellar mossy fiber conditioned stimuli on the latency of conditioned eye-blink responses in decerebrate ferrets.
Authors: Svensson P , Ivarsson M , Hesslow G
Published: June 2007

To study the role of the mossy fiber afferents to the cerebellum in classical eye-blink conditioning, in particular the timing of the conditioned responses, we compared the effects of varying a peripheral conditioned stimulus with the effects of corresponding variations of direct stimulation of the mossy fibers. In one set of experiments, decerebrate ferrets were trained in a Pavlovian eye-blink conditioning paradigm with electrical forelimb train stimulation as conditioned stimulus and electrical periorbital stimulation as the unconditioned stimulus. When stable conditioning had been achieved, the effect of increasing the intensity or frequency of the forelimb stimulation was tested. By increasing the intensity from 1 to 2 mA, or the train frequency from 50 to 100 Hz, an immediate decrease was induced in both the onset latency and the latency to peak of the conditioned response. If the conditioned stimulus intensity/frequency was maintained at the higher level, the response latencies gradually returned to preshift values. In a second set of experiments, the forelimb stimulation was replaced by direct train stimulation of the middle cerebellar peduncle as conditioned stimulus. Varying the frequency of the stimulus train between 50 and 100 Hz had effects that were almost identical to those obtained when using a forelimb conditioned stimulus. The functional meaning of the latency effect is discussed. It is also suggested that the results support the view that the conditioned stimulus is transmitted through the mossy fibers and that the mechanism for timing the conditioned response is situated in the cerebellum.
Lateral cerebellar hemispheres actively support sensory acquisition and discrimination rather than motor control.
Authors: Parsons L M , Bower J M , Gao J H , Xiong J , Li J , Fox P T
Published: June 2007

This study examined a new hypothesis proposing that the lateral cerebellum is not activated by motor control per se, as widely assumed, but is engaged during the acquisition and discrimination of tactile sensory information. This proposal derives from neurobiological studies of these regions of the rat cerebellum. Magnetic resonance imaging of the lateral cerebellar output nucleus (dentate) of humans during passive and active sensory tasks confirmed four a priori implications of this hypothesis. Dentate nuclei responded to cutaneous stimuli, even when there were no accompanying overt finger movements. Finger movements not associated with tactile sensory discrimination produced no dentate activation. Sensory discrimination with the fingers induced an increase in dentate activation, with or without finger movements. Finally, dentate activity was greatest when there was the most opportunity to modulate the acquisition of the sensory tactile data: when the discrimination involved the active repositioning of tactile sensory surface of the fingers. Furthermore, activity in cerebellar cortex was strongly correlated with observed dentate activity. This distinct four-way pattern of effects strongly challenges other cerebellar theories. However, contrary to appearances, neither our hypothesis nor findings conflict with behavioral effects of cerebellar damage, neurophysiological data on animals performing motor tasks, or cerebellar contribution to nonmotor, perceptual, and cognitive tasks.
Association of visual objects and olfactory cues in Drosophila.
Authors: Guo A , Götz K G
Published: June 2007

Context-dependent preferences in a choice between an upper and a lower visual object of otherwise identical appearance were recorded during stationary flight of the fruitfly, Drosophila melanogaster, in a flight simulator. The test animal was held in a fixed orientation at the center of a wing-beat processor that converts attempted turns into counter-rotations of a surrounding cylindrical panorama. This allowed the fly to maneuver the preferred object into the actual direction of flight. Single flies were trained to avoid a course toward the visual object that had been associated with the aversive odor benzaldehyde (BAL). Conditioned object avoidance was investigated in different treatment groups by collective evaluation of the scores from 80 long-lasting flights (> 1 hr). In addition to a significant cross-modal association, we found a striking long-term effect of transient exposure to BAL both in the embryonic and larval states. The preimaginal experience significantly increased the indifference to BAL in the adult flies. Disturbed vision does not account for this effect: Neither the perception nor the discrimination of the visual objects was significantly impaired in the investigated flies. Disturbed olfaction could explain the present results. Recently, however, preimaginal BAL uptake has been found to interfere directly with the retention of heat-shock-conditioned object avoidance.
Memory consolidation in Drosophila operant visual learning.
Authors: Xia S , Liu L , Feng C , Guo A
Published: June 2007

A new conditioning procedure, developed for the operant learning paradigm at the flight simulator, leads to stronger learning scores in wild-type flies. This procedure produces mean learning indices up to LI = 0.52. The heat-avoidance behavior acquired during training is very difficult to extinguish during extinction. Memory decays quickly during the first 3 hr after training and still is measurable 48 hr later. Disruption experiments demonstrate that memory can be disrupted by cold anesthesia within the first approximately 20 min after training, whereas KCl- and CXM-feeding regimens abolish memory soon after training and 3 hr later, respectively. These results initially suggest at least three distinct memory phases involved in memory consolidation in Drosophila after operant conditioning.
Brief theta-burst stimulation induces a transcription-dependent late phase of LTP requiring cAMP in area CA1 of the mouse hippocampus.
Authors: Nguyen P V , Kandel E R
Published: June 2007

Memory storage in the mammalian brain can be divided into a short-term phase that is independent of new protein synthesis and a long-term phase that requires synthesis of new RNA and proteins. A cellular model for these two phases has emerged from studies of long-term potentiation (LTP) in the three major excitatory synaptic pathways in the hippocampus. One especially effective protocol for inducing robust and persistent LTP is "theta-burst" stimulation, which is designed to mimic the firing patterns of hippocampal neurons recorded during exploratory behavior in intact awake animals. Unlike LTP induced by non-theta tetanization regimens, little is known about the biochemical mechanisms underlying theta-burst LTP in the hippocampus. In the present study, we examined theta-burst LTP in the Schaffer collateral pathway. We found that 3 sec of theta-burst stimulation induced a robust and persistent potentiation (theta L-LTP) in mouse hippocampal slices. This theta L-LTP was dependent on NMDA receptor activation. The initial or early phase of theta-LTP did not require either protein or RNA synthesis and was independent of cAMP-dependent protein kinase (PKA) activation. In contrast, the late phase of theta-LTP required synthesis of proteins and RNA and was blocked by inhibitors of PKA. Prior induction of theta-LTP also occluded the potentiation elicited by chemical activation of PKA. Our results show that, like non-theta LTP, theta-induced LTP in area CA1 of the mouse hippocampus also involves transcription, translation, and PKA and suggest that cAMP-mediated gene transcription may be a common mechanism responsible for the late phases of LTP induced by both theta and non-theta patterns of stimulation.
Mapping of interneurons that contribute to food aversive conditioning in the slug brain.
Authors: Kimura T , Suzuki H , Kono E , Sekiguchi T
Published: June 2007

To determine the distribution of neurons that contribute to memory formation induced by odor-taste associative conditioning in the slug's brain, we examined neuronal activity of the central nervous system of the slug Limax marginatus using a fluorescent activity marker [Lucifer yellow (LY)]. When LY was injected into the body cavity just after the conditioning, many of the procerebral (PC) interneurons were labeled. The PC lobe was considered to play important roles in the olfaction of the slug, because the olfactory afferent fibers from both the inferior and the superior tentacular noses innervate it. Such strong dye-uptake activity of PC interneurons was not observed when LY was injected just after unpaired control treatment. Thus, it was suggested that enhancement of dye-uptake activity upon conditioning was caused by the association of a conditioning stimulus (CS) with an unconditioned stimulus (UCS). The distribution patterns of PC interneurons that were labeled by LY after conditioning showed a characteristic feature: They usually formed a belt-shaped cluster parallel to the dorsoventral axis. This feature of the distribution was maintained when different odors were used as a CS. Furthermore, the number of the clusters reflected the number of CS odors but not the number of conditioning sessions. From these observations, we considered that enhancement of the neural activity involving dye uptake in each belt-shaped cluster contributed to formation of each odor memory.
Two critical periods of protein and glycoprotein synthesis in memory consolidation for visual categorization learning in chicks.
Authors: Tiunova A A , Anokhin K V , Rose S P
Published: June 2007

A protein synthesis inhibitor, anisomycin (ANI), and an inhibitor of glycoprotein synthesis, 2-deoxygalactose (2-D-gal), were used to investigate memory consolidation following visual categorization training in 2-day-old chicks. ANI (0.6 micromole/chick) and 2-D-gal (40 micromoles/chick) were injected intracerebrally at different time intervals from 1 hr before to 23 hr after the training. Retention was tested 24 hr post-training. Both ANI and 2-D-gal injections revealed two periods of memory sensitivity to pharmacological intervention. ANI impaired retention when injected from 5 min before to 30 min after the training or from 4 hr to 5 hr post-training, thus demonstrating that consolidation of long-term memory in this task requires two periods of protein synthesis. 2-D-Gal first produced an amnesia when it was injected in the interval from 5 min before to 5 min after the training. Injections made between 5 min and 5 hr post-training were without effect on the retention. The second period of memory impairment by 2-D-gal started at 5 hr post-training and lasted until 21 hr after the training. Administration of 2-D-gal made 23 hr after the training did not influence retention in the test at either 24 hr or 26 hr. These results are consistent with the hypothesis that two waves of protein and glycoprotein synthesis are necessary for the formation of long-term memory. The prolonged duration of performance impairment by 2-D-gal in the present task might reflect an extended memory consolidation period for a categorization form of learning.
Backward inhibitory learning in honeybees: a behavioral analysis of reinforcement processing.
Authors: Hellstern F , Malaka R , Hammer M
Published: June 2007

One class of theoretical accounts of associative learning suggests that reinforcers are processed according to learning rules that minimize the predictive error between the expected strength of future reinforcement and its actual strength. The omission of reinforcement in a situation where it is expected leads to inhibitory learning of stimuli indicative for such a violation of the prediction. There are, however, results indicating that inhibitory learning can also be induced by other mechanisms. Here, we present data from olfactory reward conditioning in honeybees that show that (1) one- and multiple-trial backward conditioning results in conditioned inhibition (CI); (2) the inhibition is maximal for a 15-sec interval between US and CS; (3) there is a nonmonotonic dependency on the degree of CI from the US-CS interval during backward pairing; and (4) the prior association of context stimuli with reinforcement is not necessary for the development of CI. These results cannot be explained by models that only minimize a prediction error. Rather, they are consistent with models of associative learning that, in addition, assume that learning depends on the temporal overlap of a CS with two processes, a fast excitatory and a slow inhibitory one, both evoked by a reinforcer. The fmdings from this behavioral analysis of reinforcement processing are compared with the known properties of an individual, identified neuron involved in reinforcement processing in the bee brain, to further understand the mechanisms underlying predictive reward learning.
Spatial training and high-frequency stimulation engage a common pathway to enhance glutamate release in the hippocampus.
Authors: Richter-Levin G , Canevari L , Bliss T V
Published: June 2007

We have measured depolarization-induced release of endogenous glutamate in synaptosomes prepared from the dentate gyrus after the induction of LTP by high-frequency stimulation in anesthetized rats, and after training in the water maze. Both spatial training and LTP in untrained rats were accompanied by an increase in glutamate release from dentate synaptosomes. The enhancement of synaptosomal glutamate release induced by high-frequency stimulation was abolished in well-trained rats, and was reduced in partially trained rats and in rats trained in a nonspatial task. However, the magnitude of LTP was similar in well-trained and untrained groups. These results indicate that spatial training activates a glutamate release pathway that converges with that activated in LTP, and demonstrate an unexpected dissociation between increased glutamate release and LTP.
Long-term habituation to spatial novelty in blind cave fish (Astyanax hubbsi): role of the telencephalon and its subregions.
Authors: Riedel G
Published: June 2007

Blind cave fish, when released into a novel environment, show a typical exploratory behavior characterized by high swim speed along walls shortly after release. This behavior wanes during prolonged exposure and thus may reflect habituation to novelty. As the hippocampus of mammals, which plays a crucial role in spatial learning, is part of the telencephalon, the possible involvement of this brain structure of fish was investigated in exploratory behavior. Ablation of the whole telencephalon or bilateral removal of dorsal parts of the hemispheres reduced activity; in contrast, unilateral lesions of one hemisphere, bilateral lesions of dorsal and dorsoventral parts, and removal of olfactory bulbs increased activity. However, the time course of habituation in a novel environment remained unchanged, except for ablated animals in which there was virtually no habituation in swim speed. These data suggest that the telencephalon of fish may not participate in long-term habituation to spatial novelty but, rather, support the notion of the telencephalon being involved in generation of arousal.
Efficacy of the Incredible Years Basic parent training programme as an early intervention for children with conduct problems and ADHD
Authors: Jones K. , Daley D. , Hutchings J. , Bywater T. , Eames C.
Published: June 2007

Background  The efficacy of the Incredible Years (IY) Basic parent training (PT) programme for a community‐based sample of families with pre‐school children at risk of developing both conduct problems and attention deficit hyperactivity disorder (ADHD) was examined.

Methods  Pre‐school children displaying signs of both early‐onset conduct problems and ADHD were randomly allocated to either IY PT intervention, or to a waiting list (WL) control group. Child symptoms were assessed before and after the intervention.

Results  Post intervention, the intervention group was associated with significantly lower levels of parent‐reported inattention and hyperactive/impulsive difficulties, even after controlling for post‐intervention changes in child deviance. In addition, 52% of those in the intervention condition, compared with 21% in the control condition, displayed clinically reliable improvements post intervention, giving an absolute risk reduction of 31% and a number needed to treat of 3.23.

Conclusions  Findings from this study indicate that the IY PT programme is a valuable intervention for many pre‐school children displaying early signs of ADHD.
Concurrent predictors of dysfunctional parenting and maternal confidence: implications for parenting interventions
Authors: Morawska A. , Sanders M. R.
Published: June 2007

Background  The often intense nature of the conflict between parents and their toddlers requires better understanding of what happens during this stage of development and how difficulties can be prevented from escalating in the future. Clarification of the nature of family and parenting factors related to toddler behaviour allows better capacity for intervention development and tailoring to individual families.

Methods  A total of 126 mothers of toddlers completed a self‐report assessment battery, examining child behaviour, parenting style and confidence, as well as broader family adjustment measures.

Results  The study found that maternal confidence and dysfunctional parenting were interrelated and were also predicted best by parenting variables, in contrast to socio‐demographic and child variables. Maternal confidence also mediated the relationships between family income and toddler behaviour.

Conclusions  Parenting style and confidence are important modifiable factors to target in parenting interventions. The implications for the development, implementation and delivery of parenting interventions are discussed.
Providing a children's palliative care service in the community through fixed‐term grants: the staff perspective
Authors: Beringer A. J. , Eaton N. M. , Jones G. L.
Published: June 2007

Background  Children's palliative care services have recently been awarded fixed‐term grants, aimed at improving the provision of care for children with life‐limiting conditions in the community. We report findings of a qualitative study to investigate the experience of a cohort of community children's nurses from teams involved in setting up or extending community‐based children's palliative care services. The purpose of the study was to identify factors that affect service delivery, from the staff perspective, and to suggest ways of promoting their sustainable development.

Methods  Semi‐structured telephone interviews were conducted with 21 nurses from 12 different teams providing palliative care for children at home and in hospices. Participants were questioned about the services they provided and their own roles in that provision. nvivo qualitative data analysis software was used to explore themes arising from the transcribed recorded interviews.

Findings  Key findings were the importance of physical location in facilitating multidisciplinary communication, the importance of defining role boundaries between existing and new providers of children's palliative care, and the potentially detrimental impact of insecure funding on referral patterns and recruitment to posts. Staff named the opportunity to offer direct ‘hands‐on’ care to families, access to work‐based support and networking opportunities as important factors in helping them cope with the stresses involved in managing finite resources and the emotional challenges of their work.

Conclusions  The maintenance of a mixed caseload with a significant proportion of direct care, provision of ongoing support and clearly defined roles are recommended as means of bolstering the ability of staff to develop their services. The deliberate locating of services to enhance communication between staff and guidance on the preparation of funding applications may further contribute to the sustainability of these services.
Characterization of the porcine insulin‐like growth factor‐binding protein, acid‐labile subunit gene: full‐length cDNA and DNA sequence, polymorphisms and expression profile
Authors: Li S. , Ren J. , Huang L.
Published: June 2007

Insulin‐like growth factor‐binding protein acid‐labile subunit (IGFALS) is an important glycoprotein in the circulation complex for insulin‐like growth factors‐I and ‐II (IGFs). So far only a partial porcine IGFALS sequence is available. We herein report the isolation, characterization, polymorphism identification and expression analysis of the porcine IGFALS gene. A 2000‐bp full‐length cDNA sequence was determined with 5′‐ and 3′‐Rapid Amplification of cDNA End (RACE) assay. It contains a 1821‐bp open reading frame encoding a protein of 606 amino acids with a calculated molecular mass of 66 kDa and a theoretical isoelectric point of 6.89. The deduced IGFALS protein shares high identity (70–80%) with other mammalian IGFALS. We also obtained a full‐length genomic DNA sequence of the gene. Similar to the other mammalian orthologues, particularly in terms of exon size and exon/intron boundaries, the porcine IGFALS gene spans a transcription unit of 2990 bp, consisting of two exons and one intron. Three single nucleotide polymorphisms (synonymous mutations) were identified in the DNA sequence. RT‐PCR assays indicate that IGFALS is expressed ubiquitously in pigs and transcripts are particularly abundant in the liver, lung, white adipose tissue, prostate, epididymis, thyroid and bladder.
Identification of mutations of zona pellucida glycoprotein (ZP3) and its association with pig reproductive traits
Authors: Yuan J.F. , Moaeen‐ud‐Din M. , Gong Y.Z. , Peng X.L. , Yang L.G. , Feng Y.P. , Liu J. , Hu B. , Affara N.A. , Jafer O. , Zhang S.J.
Published: June 2007

Reproduction is a complex trait, controlled by genetic and environmental factors. Genetic improvement of this trait is important for animal breeders to improve the animal's production efficiency. Apart from genetic factors, animal production can be affected by environmental factors, i.e. the nursing ability of the sow, which is in turn affected directly by effective teat number (teats producing milk normally, TN) and number of piglets born alive (NBA). The objective of this study was to find new mutations, such as single nucleotide polymorphisms (SNPs) from the Zona Pellucida glycoprotein gene (ZP3) using Single Strand Chain Polymorphism (SSCP) and nucleotide sequencing and to investigate association between genetic variations and sow reproductive traits. We identified 13 new SNPs from exon 1, two new SNPs from intron 2, one SNP from intron 6 and a 18 bp (GCACGTGGTCCTCCTGG)‐deletion/insertion from intron 2 of the ZP3 gene. Five out of these mutations were selected to genotype in five different breeds (Small Meishan, Qingping, Duroc, Landrace and Large White) and association with reproductive traits in European breeds (Duroc, Landrace and Large White). The sows with genotype AA had more 1.11 piglets NBA than of the sows with genotype AB (p < 0.05) in the 18 bp deletion/insertion of intron 2, while non‐significant associations between the other mutations and reproductive traits (NBA and TN) were found.
Relationship between phenotypic and genetic diversity of parental genotypes and the frequency of transgression effects in barley (Hordeum vulgare L.)
Authors: Kuczyńska A. , Surma M. , Kaczmarek Z. , Adamski T.
Published: June 2007

The aim of the study was to evaluate the relationship between genetic and phenotypic distances of parents and the genetic potential of crosses as measured by the frequency of transgressive segregants in homozygous populations. Material for the study involved 17 barley cross‐combinations. In each cross, the parental genotypes, F2 hybrids and doubled haploid (DH) lines were analysed. Yield and yield‐related traits were observed in the experiments. Phenotypic (univariate and multivariate) and genetic distances (GD) were investigated between pairs of parental genotypes. Genetic distance was evaluated by using random amplified polymorphic DNA markers. In F2 generations, the genetic coefficient of variability (GCV) was evaluated. Within all the cross‐combinations studied, each DH line was compared with both parents to distinguish the positive and negative transgressive lines. In addition, the coefficient of gene distribution (r) along parental genomes was evaluated. Relationships between frequency of transgression and both phenotypic and GDs, GCV and r, were assessed by regression analysis. It was found that for all the traits studied the frequency of transgressive lines depended mainly on gene distribution (r). Genetic distance between parents appeared to be significant for the occurrence of transgression effects in plant height, ear length, grain weight per ear and grain yield per plot. Regression analysis has shown that phenotypic differences between parental genotypes were also important for the frequency of transgressive lines. A weak relationship was found between the variation of F2 hybrids and the occurrence of transgressive lines. The results indicate that occurrence of transgressive segregants in a homozygous population should be considered as a phenomenon dependent simultaneously on several factors characterizing parental genotypes. Among them, the most important are: gene distribution, phenotypic diversity and GD.
QTL analysis of crown rust resistance in perennial ryegrass under conditions of natural and artificial infection
Authors: Schejbel B. , Jensen L. B. , Xing Y. , Lübberstedt T.
Published: June 2007

Crown rust is an economically devastating disease of perennial ryegrass. Both artificial crown rust inoculations, with the possibility of several selection cycles in one year, as well as marker‐assisted selection can be used for more efficient breeding of new resistant cultivars. The objective of this study was to map quantitative trait loci (QTL) for response to crown rust infection in perennial ryegrass. In order to identify relevant markers for response to crown rust infection, QTL mapping was performed on a ryegrass mapping population which was evaluated for resistance in the field for two years as well as by artificial pathogen inoculations using a detached leaf assessment. The broad sense heritability values for the field, detached leaf and combined assays were 0.42, 0.56, and 0.64, respectively, indicating a good potential for selection for crown rust resistance. A total of six QTLs were identified and mapped to linkage groups (LG) LG1, LG4 and LG5, explaining between 6.8% and 16.4% of the total phenotypic variation.
Determination of chemical composition and nutritional attributes of silage corn hybrids by near‐infrared spectroscopy on chopper: evaluation of traits, sample presentation systems and calibration transferability
Authors: Montes J. M. , Paul C. , Melchinger A. E.
Published: June 2007

Determination of dry matter and feeding value of silage corn (Zea mays L.) limits the number of genotypes that can be evaluated in breeding programmes. Measuring plot material by near‐infrared spectroscopy on chopper (NOC) allows to increase the number of genotypes to evaluate, and improves dramatically the efficiency of the data collection processes. The objectives of our study were to (i) compare the performance of two NOC sample presentation systems (conveyor belt vs. spout) for determination of dry matter and feeding value of silage corn hybrids (ii) identify limiting parameters in the performance of alternative NOC sample presentation designs and (iii) evaluate the calibration transferability between NOC systems equipped with different sample presentation designs. Two chopper machines were equipped with near‐infrared diode array spectrometers. Sample presentation designs comprised the conveyor belt and spout systems. Drying‐oven and laboratory near‐infrared spectroscopy were used as reference methods to develop NOC calibrations. In association with its higher dynamic signal range the conveyor belt system yielded lower standard errors of prediction than the spout system for most traits. Calibration transferability between NOC systems with different sample presentation designs was feasible.
Variation of freezing tolerance, Cor/Lea gene expression and vernalization requirement in Japanese common wheat
Authors: Ishibashi M. , Kobayashi F. , Nakamura J. , Murai K. , Takumi S.
Published: June 2007

Freezing tolerance and vernalization requirement are important traits for adaptation of wheat to growing in a high‐latitude area. Fr‐1 and Vrn‐1, tightly linked on homoeologous group 5 chromosomes, are major loci for controlling the freezing tolerance and vernalization requirement, respectively. It was previously supposed that winter‐habit wheat should possess a winter‐type Fr‐1 allele guaranteeing winter survival, but that such allele is unnecessary for spring‐habit cultivars. To clarify such allelic linkage between the Vrn‐1 and Fr‐1 loci in the D genome, we studied freezing tolerance and vernalization requirement, and compared cold‐responsive expression patterns of Cor (cold responsive)/Lea (late‐embryogenesis‐abundant), their putative transcription factor genes and three Vrn‐1 homoeologs in Japanese common wheat cultivars. Wide variation of freezing tolerance and two alleles of Vrn‐D1 were observed in the Japanese cultivars, whereas the accumulation levels of the Cor/Lea transcripts were not be correlated with the levels of freezing tolerance. The allelic linkage between Vrn‐1 and Fr‐1 loci well known in the A genome was not observed in the D genome of Japanese cultivars possessing Vrn‐D1 or vrn‐D1 allele.
The unstable tubular ray flower allele of sunflower: inheritance of the reversion to wild‐type
Authors: Fambrini M. , Michelotti V. , Pugliesi C.
Published: June 2007

The tubular ray flower (turf) mutant of sunflower (Helianthus annuus L.) is characterized by a change from a zygomorphic corolla to a nearly actinomorphic tubular‐like corolla of ray flowers that also achieves the ability to differentiate fertile stamens and ovules. The recessive turf mutation is found to be unstable, spontaneously reverting to a wild‐type or nearly wild‐type phenotype. Reversion frequencies were 1.70% in the original inbred line R1634 (where turf was first identified), 0.17% and 3.20% in two turf/turf homozygous F3 progenies, derived from crossing a turf mutant with two different inbred lines. As no chimeric plant was found it is likely that the reversion had occurred either in the germ line or within the zygote. Self‐pollinated wild‐type reverted plants segregated into normal and mutant phenotypes fitting a monogenic 3 : 1 ratio, thus indicating that the reversion affected a single allele. The hypothesis of an epigenetic mechanism is discussed.
Effects of Grade of Oocyte–Cumulus Complex and the Interactions Between Grades on the Production of Blastocysts in the Cow, Ewe and Lamb
Authors: Kelly JM , Kleemann DO , Rudiger SR , Walker SK
Published: June 2007

Contents

There is an association between the size of the cumulus investment and the in vitro developmental ability of the oocyte–cumulus complex (OCC) that provides a basis for the selection of OCCs. However, the value of selection is confounded by humoral interactions between OCCs that influence the development of OCCs of other grade(s). This study examined the effect of size of the cumulus investment (OCC grade) and the interactions between grades on the developmental ability of oocytes collected from the cow, ewe and lamb. OCCs were classified into A, B and C grades on visual assessment of the number of cumulus cell layers or left unselected (Unselected). In the cow, there were 669 ± 228 to 4763 ± 228 cells per OCC whereas comparable figures in the ewe and lamb were 593 ± 252 to 3716 ± 252 and 366 ± 228 to 3263 ± 228 respectively (A > Unselected > B > C; Experiment 1). In Experiment 2, OCCs were made to mature within grade and the efficiency of blastocyst production and blastocyst quality was compared with that obtained in the Unselected group. Grade was associated with significant (p < 0.05) differences in cleavage rate, blastocyst production rate and the mean number of nuclei per embryo (generally A > B > C across animal types). However, the performance of A grade OCCs in the cow and lamb did not differ significantly from that obtained in the Unselected group whereas in the ewe, A grade OCCs were significantly (p < 0.05) better. Furthermore, the performance of the Unselected group was significantly (p < 0.05) better than that of the combined grades (A + B + C) in the cow but there were no differences in either the ewe or lamb. It is concluded that (i) interactions between OCCs of different grade influence the developmental ability of OCCs in the cow and, to a lesser extent, the lamb, (ii) selection of OCCs in the cow and lamb would lead to the exclusion of many OCCs that have the ability to develop into blastocysts and (iii) selection in the ewe would improve the efficiency of blastocyst production although its value is limited by the low percentage of A grade OCCs.
Prevalence of thyroid disease in an older Australian population
Authors: Empson M. , Flood V. , Ma G. , Eastman C. J. , Mitchell P.
Published: June 2007

Aim: To determine the prevalence of thyroid disease in an older Australian population in a population‐based cross‐sectional study.

Background: Community‐living subjects, aged 49 years or older, in two Blue Mountains postcodes were invited to participate in an eye, nutrition and health study between 1997 and 2000.

Methods: Three thousand five hundred and nine of the 4489 identified persons participated. Fifty‐seven per cent of 3504 who completed questionnaires were women; their mean age was 66.8 years. Thyroid‐stimulating hormone (TSH) was measured in 2665 subjects (76% of those completing the questionnaire). The main outcome measures were serum TSH and free thyroxine levels, serum lipids, urate and sugar levels and questionnaire responses.

Results: The prevalence of recognized thyroid disease (either self‐reported history of thyroid disease or current thyroxine treatment) was 10% (95% confidence interval (CI) 8.9–11.1%). An additional 3.6% (95%CI 2.9–4.3%) of participants had unrecognized thyroid disease (abnormal TSH). The TSH was abnormal in 7.1% (95%CI 5.8–8.4%) of women and 3.7% (95%CI 2.6–4.8%) of men. Sixty‐five per cent of those with an abnormal TSH did not report a history of thyroid disease, whereas 25% of those taking thyroxine replacement therapy had an abnormal TSH level. The prevalence of hypothyroidism increased with increasing age in women. The mean fasting cholesterol was 0.36 mmol/L (95%CI 0.15–0.57) higher in hypothyroid subjects than in euthyroid subjects.

Conclusion: Thyroid disease in older Australian women is relatively common and may be undiagnosed. Ongoing monitoring of patients on thyroxine replacement therapy is important, given that 25% of treated patients had an abnormal TSH.
Diagnostic and prognostic utility of the serum free light chain assay in patients with AL amyloidosis
Authors: Morris K. L. , Tate J. R. , Gill D. , Kennedy G. , Wellwood J. , Marlton P. , Bird R. , Mills A. K. , Mollee P.
Published: June 2007

Background: Organ dysfunction in AL amyloidosis is related to the production and deposition of amyloidogenic monoclonal light chains. These pathological light chains can now be quantified using the recently developed serum free light chain assay.

Methods: We retrospectively reviewed 31 patients with AL amyloidosis to determine the frequency of abnormal free light chain assay results at diagnosis and whether changes in the serum free light chain assay predict outcome after therapy.

Results: An abnormal free light chain assay was found in 30 of 31 patients (97%) at the time of diagnosis. In the subset of our patients who received treatment for AL amyloidosis, a >50% reduction of the pathological free light chain following treatment was shown to predict improved overall survival. In our series of analyses, achievement of greater magnitudes of reduction of the free light chain result did not appear to provide additional prognostic information, nor did the baseline free light chain result predict outcome.

Conclusion: Our findings support the use of the free light chain assay in the diagnostic work‐up of patients with suspected AL amyloidosis, and also as a sensitive biomarker of response to therapy.
Clinical perspectives in lymphoma
Authors: Young G. A. R. , Iland H. J.
Published: June 2007

The classification of both Hodgkin’s and non‐Hodgkin’s lymphomas continues to evolve. The current World Health Organization classification incorporates data derived from advances in our understanding of the pathogenesis of these disorders together with their distinguishing immunophenotypic, genotypic, clinical and histopathological characteristics. As outcomes have improved, the main emphasis of treatment has been to incorporate a risk‐adapted approach to reduce long‐term toxicity without sacrificing efficacy through the use of varying combinations of chemotherapy, radiotherapy and immunotherapy.
Novel and diverse integron integrase genes and integron‐like gene cassettes are prevalent in deep‐sea hydrothermal vents
Authors: Elsaied Hosam , Stokes H. W. , Nakamura Takamichi , Kitamura Keiko , Fuse Hiroyuki , Maruyama Akihiko
Published: June 2007

The lack of information about mobile DNA in deep‐sea hydrothermal vents limits our understanding of the phylogenetic diversity of the mobile genome of bacteria in these environments. We used culture‐independent techniques to explore the diversity of the integron/mobile gene cassette system in a variety of hydrothermal vent communities. Three samples, which included two different hydrothermal vent fluids and a mussel species that contained essentially monophyletic sulfur‐oxidizing bacterial endosymbionts, were collected from Suiyo Seamount, Izu‐Bonin, Japan, and Pika site, Mariana arc. First, using degenerate polymerase chain reaction (PCR) primers, we amplified integron integrase genes from metagenomic DNA from each sample. From vent fluids, we discovered 74 new integrase genes that were classified into 11 previously undescribed integron classes. One integrase gene was recorded in the mussel symbiont and was phylogenetically distant from those recovered from vent fluids. Second, using PCR primers targeting the gene cassette recombination site (59‐be), we amplified and subsequently identified 60 diverse gene cassettes. In multicassette amplicons, a total of 13 59‐be sites were identified. Most of these sites displayed features that were atypical of the features previously well conserved in this family. The Suiyo vent fluid was characterized by gene cassette open reading frames (ORFs) that had significant homologies with transferases, DNA‐binding proteins and metal transporter proteins, while the majority of Pika vent fluid gene cassettes contained novel ORFs with no identifiable homologues in databases. The symbiont gene cassette ORFs were found to be matched with DNA repair proteins, methionine aminopeptidase, aminopeptidase N, O‐sialoglycoprotein endopeptidase and glutamate synthase, which are proteins expected to play a role in animal/symbiont metabolism. The success of this study indicates that the integron/gene cassette system is common in deep‐sea hydrothermal vents, an environment type well removed from anthropogenic disturbance.
Inhibition of the resuscitation from the viable but non‐culturable state in Enterococcus faecalis
Authors: Del Mar Lleò Maria , Benedetti Dennis , Tafi Maria Carla , Signoretto Caterina , Canepari Pietro
Published: June 2007

The viable but non‐culturable (VBNC) state is a survival strategy adopted by bacteria when exposed to environmental stresses capable of inducing cell growth inhibition and cell death. This state can be summarized as a quiescent form of life waiting for suitable conditions. This strategy has been shown to be activated by medically important bacteria either when present in natural environments or in the human body during the infection process. In this study we have evaluated the effects of antibiotics acting on peptidoglycan or protein synthesis of Enterococcus faecalis in the VBNC state. The activity of the antibiotics was determined by their ability both to inhibit resuscitation (i.e. recovery of cell division) and to bind the molecular target of action. Benzylpenicillin, piperacillin and gentamicin block cell resuscitation at the minimal inhibitory concentrations (MICs) of growing cells, while vancomycin acts only at doses 500 times higher than the MIC. This different behaviour is discussed taking into consideration the mode of action of the antibiotics.