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In order to clarify the optimal planting density of soybean variety Liaodou No.21 in Luoping County, Liaodou No.21 was taken as the experimental material, and five density treatments were set up by using the randomized block design, including Treatment A (20 plants·m-2), Treatment B (25 plants·m-2), Treatment C (30 plants·m-2), Treatment D (35 plants·m-2), and Treatment E (40 plants·m-2). Then, the effects of different planting densities on the growth dynamics, agronomic traits and yield of Liaodou No.21 were studied. The results showed that the planting density had a great influence on the yield of Liaodou No.21. When the planting density was 30 plants·m-2, the total yield reached its maximum value of 2933.6 kg·hm-2. The lower planting density resulted in the insufficient number of soybean populations, while the planting density was too high, it was difficult for the individual plants to obtain sufficient nutrients, energy, and water for their growth. Therefore, an appropriate planting density was crucial for improving the yield of Liaodou No.21. [ABSTRACT FROM AUTHOR]

A comprehensive understanding of phylogeography requires the integration of knowledge across different organisms, ecosystems, and geographic regions. However, a critical knowledge gap exists in the arid biota of the vast Asian drylands. To narrow this gap, here we test an "out-of-Central Asia" hypothesis for the desert scorpion Mesobuthus mongolicus by combining Bayesian phylogeographic reconstruction and ecological niche modeling. Phylogenetic analyses of one mitochondrial and three nuclear loci and molecular dating revealed that M. mongolicus represents a coherent lineage that diverged from its most closely related lineage in Central Asia about 1.36 Ma and underwent radiation ever since. Bayesian phylogeographic reconstruction indicated that the ancestral population dispersed from Central Asia gradually eastward to the Gobi region via the Junggar Basin, suggesting that the Junggar Basin has severed as a corridor for Quaternary faunal exchange between Central Asia and East Asia. Two major dispersal events occurred probably during interglacial periods (around 0.8 and 0.4 Ma, respectively) when climatic conditions were analogous to present-day status, under which the scorpion achieved its maximum distributional range. M. mongolicus underwent demographic expansion during the Last Glacial Maximum, although the predicted distributional areas were smaller than those at present and during the Last Interglacial. Development of desert ecosystems in northwest China incurred by intensified aridification might have opened up empty habitats that sustained population expansion. Our results extend the spatiotemporal dimensions of trans-Eurasia faunal exchange and suggest that species' adaptation is an important determinant of their phylogeographic and demographic responses to climate changes. [ABSTRACT FROM AUTHOR]

Background: Symptoms of depression and pain often overlap, and they negatively influence the prognosis and treatment outcome of both conditions. However, the comorbidity of depression and pain has not been examined using network analysis, especially in the context of a pandemic. Thus, we mapped out the network connectivity among the symptoms of depression and pain in Wuhan residents in China during the late stage of the COVID-19 pandemic. Methods: This cross-sectional study was conducted from May 25, 2020 to June 18, 2020 in Wuhan, China. Participants' depressive and pain symptoms were assessed using the 9-item Patient Health Questionnaire (PHQ9) and a pain numeric rating scale (NRS), respectively. Network analyses were performed. Results: In total, 2,598 participants completed all assessments. PHQ4 (fatigue) in the depression community showed the highest strength value, followed by PHQ6 (worthlessness) and PHQ2 (depressed or sad mood). PHQ4 (fatigue) was also the most key bridge symptom liking depression and pain, followed by PHQ3 (sleep difficulties). There were no significant differences in network global strength (females: 4.36 vs. males: 4.29; S = 0.075, P = 0.427), network structure-distribution of edge weights (M = 0.12, P = 0.541), and individual edge weights between male and female participants. Conclusion: Depressive and pain symptoms showed strong cross-association with each other. "Fatigue" was the strongest central and bridge symptom in the network model, while "sleep difficulties" was the second strongest bridge symptom. Targeting treatment of both fatigue and sleep problems may help improve depressive and pain symptoms in those affected. [ABSTRACT FROM AUTHOR]

We aimed to assess the relationship of urine phthalate metabolite concentrations with anthropometric indices, and blood pressure in first-grade children. We detected 11 phthalate metabolites in urine and estimated anthropometric indices, including skinfold measurements, waist circumference (WC), and body mass index (BMI) in 276 children aged 6-8 years. Multivariate linear regression models were used to assess the associations between urinary phthalate metabolite levels, and anthropometric and blood pressure indices in a gender-specific manner. In boys, a 1-ng/mL increase in monobenzyl phthalate (MBzP) concentration was associated with a 0.027-cm decrease in the skinfold measurement (95% confidence interval [CI], − 0.053 to 0.001), whereas a 1-ng/mL increase in mono-ethyl-phthalate (MEP) concentration was associated with a 0.016-mm Hg decrease in systolic blood pressure (95% CI, − 0.031 to 0.001). MBzP, mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), and MEOHP concentrations were also inversely associated with WC. However, in girls, MEP concentrations were positively associated with chest measurements, but were inversely associated with WC. A 1-ng/mL increase in monomethyl phthalate concentrations was associated with a 0.039-cm increase in skinfold measurements (95% CI, 0.002 to 0.076), whereas a 1-ng/mL increase in MECPP concentrations was associated with a 0.050 cm decrease in skinfold measurements (95% CI, − 0.095 to − 0.005). In this exploratory, cross-sectional analysis, we identified various interesting associations between different phthalate metabolite levels and anthropometric indices, which suggest that some of phthalate metabolite should be considered in addition to the prevalence rates of overweight and obesity. [ABSTRACT FROM AUTHOR]

Aim To appraise existing alcohol guidelines for identifying and managing harmful alcohol use in primary healthcare settings. Methods Seven databases and 18 health organization or medical society websites were systematically searched from inception to 31 October 2016. Guidelines in English language, developed by a national or international medical specialty society, government or health organization, and containing recommendations for identifying and managing harmful use of alcohol in primary healthcare settings, were included. The Appraisal of Guidelines Research and Evaluation II (AGREE II) instrument was used to appraise the guidelines. Results Of the 970 literature identified, 17 were included for review, with 13 guidelines developed for use in Western countries and 4 for international use. The AGREE II scores ranged from 2.0 to 5.3, out of 7. Variations in terminology of harmful alcohol use were seen, with 'harmful drinking' and 'problem drinking' being mostly used. All guidelines were in favor of screening and brief interventions due to their effectiveness and cost-effectiveness. Potential benefits and costs of applying screening and brief interventions were found, but there was a lack of evidence for long-term effects or specific populations. Conclusions All 17 guidelines recommended screening and brief interventions due to its associated health and financial benefits. Policy makers are highly encouraged to integrate these practices into primary healthcare settings taking the drinking status, culture and resources into account. Short summary Screening and brief interventions were recommended by all 17 guidelines on managing patients with harmful use of alcohol in primary healthcare settings. Policy makers and healthcare practitioners are highly encouraged to implement these recommendations. [ABSTRACT FROM AUTHOR]

Background: Mindfulness-based cognitive therapy (MBCT) is a potential treatment for chronic insomnia. We evaluated the efficacy of MBCT for insomnia (MBCT-I) by comparing it with a sleep psycho-education with exercise control (PEEC) group.Methods: Adults with chronic primary insomnia (n = 216) were randomly allocated to the MBCT-I or PEEC group. The MBCT-I included mindfulness and psycho-education with cognitive and behavioural components under cognitive behavioural therapy for insomnia. PEEC included psycho-education of sleep hygiene and stimulus control, and exercises. Any change in insomnia severity was measured by the Insomnia Severity Index (ISI). Secondary outcomes included sleep parameters measured by a sleep diary, health service utilisation, absence from work and mindfulness measured by the Five Facet Mindfulness Questionnaire.Results: The ISI score significantly decreased in the MBCT-I group compared with the PEEC group at 2 months (i.e., post-intervention) (p = 0.023, effect size [95% CI] -0.360 [-0.675, -0.046]) but not at 5 or 8 months. Treatment response rates and remission rates based on the ISI cut-off scores were not significantly different between groups. Wake time after sleep onset (WASO) was less in the MBCT-I group at 2 and 5 months. At 8 months, both groups showed a reduced ISI score, sleep onset latency and WASO, and increased sleep efficiency and total sleep time; however, no group differences were seen. Other outcome measures did not significantly improve in either group.Conclusions: Long-term benefits were not seen in MBCT-I when compared with PEEC, although short-term benefits were seen. [ABSTRACT FROM AUTHOR]

Clear knowledge about trophic interactions among species contributes to understanding biodiversity structuring and ecosystem functioning. However, identification of host-parasitoid interactions is often impeded by the hyper-diversity of parasitoid community and their immature stages under study. As a consequence, our knowledge on host-parasitoid interactions is rather incomplete and many trophic links are still missing. In this study, we discovered that the scuttle flyMegaselia scalaris(Loew 1866) facultatively infested the scorpions ofMesobuthus eupeus mongolicus(Birula, 1911). We monitored the parasitoidism process in laboratory and obtained the parasitoid adults. The parasitoids were identified by examination of morphological characteristics and genetic analyses of mitochondrial DNA sequences from both larvae and adults. Ecological niche modelling revealed that climatically suitable areas for both parasitoids and scorpions stretch in northwest China. Our results unveiled the missing trophic links between Phoridae and Buthidae, and our morphological description and genetic inventory will provide the basic data for future studies on the exceptionally polyphagous and cosmopolitan insect species,M. scalaris. [ABSTRACT FROM AUTHOR]

The black-spotted pond frog Pelophylax nigromaculatus is a typical temperate-adapted amphibian species, largely endemic to East Asia. It occurs from central, east, and northeast China, to the Russian Far East, the Korean Peninsula, and part of Japan. So far, little is known about this frog from the Loess Plateau, a region that has experienced profound changes in climate and environment since the late Miocene. Particularly, between the Loess Plateau and the North China Plain, stand the Lüliang and Taihang mountain ranges, which form an important geographical divide in East China. Therefore, frogs from the Loess Plateau are indispensable for understanding the biogeography and evolution of this species. In this study, a total of 933 specimens of P. nigromaculatus collected range-wide were sequenced for the mitochondrial Cyt b gene, with 345 of them being genotyped at 10 nuclear microsatellite loci. Both mitochondrial and microsatellite data resolved four major frog clades: (i) Loess Plateau clade, containing only frogs from the Loess Plateau; (ii) East China clade, containing frogs from the rest of China except those from the Liaodong Peninsula; (iii) Peninsulas clade, comprising frogs from the Korean Peninsula and Liaodong Peninsula; and (iv) Japan clade. Frogs from the Loess Plateau have deeply diverged from frogs in the remaining regions, with 11.5%-13.1% sequence divergence, which is comparable to distances between congeneric ranid species. Ecological niche modeling analysis showed that the potential distribution ranges of the Loess Plateau frogs and the non-Loess Plateau frogs are rather different; niche identity testing indicated that the environmental niches of frogs from the Loess Plateau and other regions are not equivalent. Our data thus suggest that the Loess Plateau frogs represent a cryptic species. The uplift of the Lüliang Mountains was the most plausible trigger of this cryptic diversification. [ABSTRACT FROM AUTHOR]

Due to the polymorphism in the ancestral species and the stochastic fluctuation of the coalescent process, the divergence time between sequences from two closely related species varies throughout the genome. This variation is described by an exponential distribution. Gene flow between the species causes additional variation in the sequence divergence time, beyond the expected variation from the ancestral coalescent process. This prediction can be used to test for gene flow between species using genomic sequence data., A previous implementation of the model used an empirical beta distribution to describe the variation in species divergence time across the genome, with numerical integration used to calculate the 3D integrals involved in the likelihood function. However, with a huge number of loci, the numerical integration is not accurate enough, so the false-positive rate of the likelihood ratio test may exceed the significance level., In this study, we replace the beta model with a discretized version, so that the likelihood calculation involves 2D integrals. We implement the new discrete-beta model in the program 3 s and also extend our previous implementation to accommodate loci with different data configurations. We use computer simulation to examine the false-positive rate, the power and the robustness of the likelihood ratio test., The results show that the test had low false-positive rates and had even higher power in detecting gene flow than a likelihood ratio test based on a proper implementation of the isolation-with-migration model. It is, however, not robust to high levels of recombination within locus. Application of the test to two empirical data sets (from the hominoid genomes and from the Drosophila fruit flies) suggests the presence of gene flow for both data sets. [ABSTRACT FROM AUTHOR]

Objective The optimal sites and stimulation protocols for brain stimulation in epilepsy have not been found. Clinical trials, which have shown modest benefit in seizure reduction, have involved patients with poorly localized intractable focal epilepsy and stimulation sites without clear relations to specific underlying seizure circuits. The medial dorsal thalamic nucleus is a key node in limbic seizure circuits, and we wished to know what stimulation parameters might control seizures in a kindling model of limbic epilepsy. Methods In urethane-anesthetized rats, we induced limbic seizures by stimulation of the piriform cortex or CA3 of the hippocampus while recording in the entorhinal cortex or CA1 of the contralateral hippocampus to determine the effect of specific stimulation parameters on seizure duration. Results Stimulation consistently suppressed seizure duration from baseline by over 80% (p < 0.001), frequently completely preventing the seizures. Position of the thalamic electrode, stimulus intensity and frequency had a significant influence, with higher stimulus intensities (40 V vs. 20 V) and frequencies (20 Hz vs. 7 Hz) significantly suppressing seizures. The most effective position was the lateral dorsal area of the medial dorsal nucleus (MD), which corresponded to the region of axon entry. Stimulation in the MD center was not effective. An anterior-posterior relationship of the stimulating electrode pair was effective, whereas a medial lateral orientation was not. Successful stimulation suppressed the evoked responses in the entorhinal cortex or CA1. Significance Position and orientation of the stimulating electrode has to be precise, which suggests that the placement of the electrodes must be tailored to the individual's own seizure circuit. The data also indicate that successful deep brain stimulation induces a fundamental change in system physiology, which could be a marker to guide the development of stimulation parameters for each patient. [ABSTRACT FROM AUTHOR]

The aridification from Middle Miocene onwards has transformed the Asian interior into an arid environment, and the Pleistocene glacial-interglacial oscillations exerted further ecological impact. Therefore, both aridification and glaciation would have considerably influenced the evolution of many mid-latitude species in temperate Asia. Here, we tested this perspective by a phylogeographic study of the mesobuthid scorpions across temperate Asia using one mitochondrial and three nuclear genes. Concordant mitochondrial and nuclear gene trees were obtained, which are consistent with species tree inferred using a Bayesian approach. The age of the most recent common ancestor ( MRCA) of all the studied scorpions was estimated to be 12.49 Ma (late Middle Miocene); Mesobuthus eupeus diverged from the clade composing Mesobuthus caucasicus and Mesobuthus martensii in early Late Miocene (10.21 Ma); M. martensii diverged from M. caucasicus at 5.53 Ma in Late Miocene. The estimated MRCA ages of M. martensii and the Chinese lineage of M. eupeus were 2.37 and 0.68 Ma, respectively. Central Asia was identified as the ancestral area for the lineage leading to M. martensii and M. caucasicus and the Chinese lineage of M. eupeus. The ancestral habitat of the genus Mesobuthus is likely to have been characterized by an arid environment; a shift towards more humid habitat occurred in the MRCA of M. martensii and a lineage of M. caucasicus, finally leading to the adaptation of M. martensii to humid environment. Our data strongly support the idea that the stepwise intensified aridifications from Mid- Miocene onwards drove the diversification of mesobuthid scorpions, and suggest that M. martensii and M. eupeus observed today in China originated from an ancestral lineage distributed in Central Asia. Both the colonization and the ensuing evolution of these species in East Asia appear to have been further moulded by Quaternary glaciations. [ABSTRACT FROM AUTHOR]

Genetic differentiation of populations has been traditionally quantified by Wright's F-statistics, typically assuming mutation-migration-drift equilibrium. However, the equilibrium perspective can be unrealistic as many natural populations are likely not yet in equilibrium. Therefore, understanding the behaviors, robustness, and power of the differentiation indexes under non-equilibrium conditions has important implications. Here, we report an extensive examination of the properties of two major indexes GST and D under non-equilibrium conditions by theoretical deduction under the infinite allele model (IAM) and simulation under the stepwise mutation model (SMM). Several properties of GST and D valid under both SMM and IAM, which have not been recognized under the equilibrium perspective, were unveiled. First, if gene flow is very weak (e.g., m < 10−4), GST, like D, also takes a fairly long time to reach equilibrium if mutation rate is not very large. When GST ( D) is in equilibrium depends on when HS and HT are both in equilibrium. Under IAM and complete isolation, this is determined by the product of µ and t: GST will not approach equilibrium as long as µt ≪ 1. Under SMM, 10−4 appears to be the rough threshold migration rate; when m < 10−4, GST approaches equilibrium much slower and later than HS, whereas the opposite is true when m > 10−4. Second, contrary to the popular belief, µ ≪ m is neither an obligatory request for GST to be an effective differentiation measure nor a sufficient condition for using GST to estimate gene flow level ( Nm), if GST is not yet approaching equilibrium. Third, under SMM (but not IAM) and complete isolation, when population size is large (e.g., ≥1000), mutation rate shows a great impact on GST but only a mild influence on D; hence D can be much less sensitive to mutation rate heterogeneity than GST in certain situations. Fourth, whatever the level of gene flow, drift plays a dominant role on GST, whereas gene flow appears to have a stronger influence on D when subpopulations exchange individuals (even only infrequently). Moreover, GST appears to have a larger power to detect recent population genetic events than D. Finally, it is the migration rate ( m), not the absolute number of migrants ( Nm), that determines the speed at which GST or D approaches equilibrium. These results suggest that GST and D bear unique revealing powers under non-equilibrium conditions. [ABSTRACT FROM AUTHOR]

A Bayesian coalescent-based method has recently been proposed to delimit species using multilocus genetic sequence data. Posterior probabilities of different species delimitation models are calculated using reversible-jump Markov chain Monte Carlo algorithms. The method accounts for species phylogenies and coalescent events in both extant and extinct species and accommodates lineage sorting and uncertainties in the gene trees. Although the method is theoretically appealing, its utility in practical data analysis is yet to be rigorously examined. In particular, the analysis may be sensitive to priors on ancestral population sizes and on species divergence times and to gene flow between species. Here we conduct a computer simulation to evaluate the statistical performance of the method, such as the false negatives (the error of lumping multiple species into one) and false positives (the error of splitting one species into several). We found that the correct species model was inferred with high posterior probability with only one or two loci when 5 or 10 sequences were sampled from each population, or with 50 loci when only one sequence was sampled. We also simulated data allowing migration under a two-species model, a mainland-island model and a stepping-stone model to assess the impact of gene flow (hybridization or introgression). The behavior of the method was diametrically different depending on the migration rate. Low rates at < 0.1 migrants per generation had virtually no effect, so that the method, while assuming no hybridization between species, identified distinct species despite small amounts of gene flow. This behavior appears to be consistent with biologists' practice. In contrast, higher migration rates at ≥ 10 migrants per generation caused the method to infer one species. At intermediate levels of migration, the method is indecisive. Our results suggest that Bayesian analysis under the multispecies coalescent model may provide important insights into population divergences, and may be useful for generating hypotheses of species delimitation, to be assessed with independent information from anatomical, behavioral, and ecological data. [ABSTRACT FROM PUBLISHER]

The cotton bollworm Helicoverpa armigera and the oriental tobacco budworm H. assulta are sibling species, both being important agricultural pests. Morphologically, the two insects are almost indistinguishable at the egg, larval and pupal stages. One of the big challenges in the study of these insects, in particular in integrated pest management, is a timely and dependable identification of these insects at their early stages of development. Here, we report a H. armigera-specific nuclear DNA marker, and demonstrate that it can be employed to reliably discriminate between H. armigera and H. assulta by simple polymerase chain reaction amplification experiment. [ABSTRACT FROM AUTHOR]

The genetic differentiation of populations is a key parameter in population genetic investigations. Wright's F (and its relatives such as G) has been a standard measure of differentiation. However, the deficiencies of these indexes have been increasingly realized in recent years, leading to some new measures being proposed, such as Jost's D ( Molecular Ecology, 2008; , 4015). The existence of these new metrics has stimulated considerable debate and induced some confusion on which statistics should be used for estimating population differentiation. Here, we report a simulation study with neutral microsatellite DNA loci under a finite island model to compare the performance of G and D, particularly under nonequilibrium conditions. Our results suggest that there exist fundamental differences between the two statistics, and neither G nor D operates satisfactorily in all situations for quantifying differentiation. D is very sensitive to mutation models but G noticeably less so, which limits D's utility in population parameter estimation and comparisons across genetic markers. Also, the initial heterozygosity of the starting populations has some important effects on both the individual behaviours of G and D and their relative behaviours in early differentiation, and this effect is much greater for D than G. In the early stages of differentiation, when initial heterozygosity is relatively low (<0.5, if the number of subpopulations is large), G increases faster than D; the opposite is true when initial heterozygosity is high. Therefore, the state of the ancestral population appears to have some lasting impacts on population differentiation. In general, G can measure differentiation fairly well when heterozygosity is low whatever the causes; however, when heterozygosity is high (e.g. as a result of either high mutation rate or high initial heterozygosity) and gene flow is moderate to strong, G fails to measure differentiation. Interestingly, when population size is not very small (e.g. N ≥ 1000), G measures differentiation quite linearly with time over a long duration when gene flow is absent or very weak even if mutation rate is not low (e.g. μ = 0.001). In contrast, D, as a differentiation measure, performs rather robustly in all these situations. In practice, both indexes should be calculated and the relative levels of heterozygosities (especially H) and gene flow taken into account. We suggest that a comparison of the two indexes can generate useful insights into the evolutionary processes that influence population differentiation. [ABSTRACT FROM AUTHOR]

Motivation: Cancer is well known to be the end result of somatic mutations that disrupt normal cell division. The number of such mutations that have to be accumulated in a cell before cancer develops depends on the type of cancer. The waiting time Tm until the appearance of m mutations in a cell is thus an important quantity in population genetics models of carcinogenesis. Such models are often difficult to analyze theoretically because of the complex interactions of mutation, drift and selection. They are also computationally expensive to simulate because of the large number of cells and the low mutation rate.Results: We develop an efficient algorithm for simulating the waiting time Tm until m mutations under a population genetics model of cancer development. We use an exact algorithm to simulate evolution of small cell populations and coarse-grained τ-leaping approximation to handle large populations. We compared our hybrid simulation algorithm with the exact algorithm in small populations and with available asymptotic results for large populations. The comparison suggested that our algorithm is accurate and computationally efficient. We used the algorithm to study the waiting time for up to 20 mutations under a Moran model with variable population sizes. Our new algorithm may be useful for studying realistic models of carcinogenesis, which incorporates variable mutation rates and fitness effects.Contact: z.yang@ucl.ac.uk [ABSTRACT FROM AUTHOR]

The potential effectiveness of statistical haplotype inference makes it an area of active exploration over the last decade. There are several complications of statistical inference, including: the same algorithm can produce different solutions for the same data set, which reflects the internal algorithm variability; different algorithms can give different solutions for the same data set, reflecting the discordance among algorithms; and the algorithms per se are unable to evaluate the reliability of the solutions even if they are unique, this being a general limitation of all inference methods. With the aim of increasing the confidence of statistical inference results, consensus strategy appears to be an effective means to deal with these problems. Several authors have explored this with different emphases. Here we discuss two recent studies examining the internal algorithm variability and among-algorithm discordance, respectively, and evaluate the different outcomes of these analyses, in light of Orzack (2009) comment. Until other, better methods are developed, a combination of these two approaches should provide a practical way to increase the confidence of statistical haplotyping results. [ABSTRACT FROM AUTHOR]

The evolutionary conservation and versatility of a new set of nuclear primers for the amplification of the ribosomal internal transcribed spacer regions in insects and other invertebrates have been studied. These primers, conserved across Insecta and other invertebrates, are based on a comprehensive taxonomic survey of the current DNA sequence databases. Their versatility was demonstrated by extensive polymerase chain reaction assays in 16 species from two arachnid orders, eight insect orders, three invertebrate and vertebrate chordate orders and by direct sequencing of the amplified products. The availability of these primers to the insect research community should facilitate the use of internal transcribed spacer regions in intraspecific studies as well as phylogenetic analysis of closely related taxa. [ABSTRACT FROM AUTHOR]

Eight polymorphic di- and trinucleotide microsatellite loci suitable for population genetic analysis were developed in Locusta migratoria from a partial phagemid genomic library enriched for microsatellite inserts. The expected heterozygosity at these loci ranges from 0.45 to 0.97, with the observed allele numbers varying between nine and 45. The overall microsatellite cloning efficiency in L. migratoria is 14%, suggesting that in migratory locusts, microsatellite sequences are abundant and should provide a valuable and easily accessible source of nuclear markers for genetic studies. These microsatellite loci were highly Locusta-specific, with only very limited cross-species applicability. [ABSTRACT FROM AUTHOR]

The physiology and pharmacology of CA1 is changed in epilepsy. There is evidence that the thalamic input to CA1 has a somewhat different physiological effect compared with the CA3 input. In this study we sought to determine whether this difference in physiology persists in epilepsy, and whether there are changes in the pharmacologic profile of these responses. Under urethane two stimulating electrodes were placed in mid to ventral CA3 and in the midline thalamus of control or epileptic rats. One glass micropipette electrode was placed into CA1 for recording. After the baseline acquisition of CA1-evoked responses to single- or paired-pulse stimulation, the stimuli were repeated with local application of either the GABAA agonist muscimol or the NMDA antagonist dl-2-amino-5-phosphonovalerate (APV). The CA1 response of epileptic rats had a smaller population postsynaptic potential (PSP) and spike amplitudes, longer PSP duration, multiple spikes, and the paired-pulse (at 20-ms intervals) facilitation in contrast to the paired-pulse depression seen in control and kindled rats. The duration of the PSP as well as the amplitude and number of spikes were reduced by administration of APV or muscimol into CA1 in both control and epileptic rats. In control rats, APV enhanced the depression induced by maximal paired thalamic or CA3 stimulation at 20-ms intervals and reduced the facilitation of threshold stimulation into no change. In contrast, muscimol in control rats reversed the depression induced by paired maximal stimulation into a mild facilitation and reduced the facilitation of threshold stimulation. In epileptic rats neither APV nor muscimol had a significant effect on the changes of the CA1 responses induced by maximal or threshold paired stimulation. This initial in vivo study demonstrated that the physiology and pharmacology of CA1 in epileptic rats are different from control rats. Although there are physiological differences in the evoked responses that are linked to the site of stimulation in the control and epileptic group, the pharmacology in each condition is independent of the site of stimulation. [ABSTRACT FROM AUTHOR]

Abstract Population-genetic studies have been remarkably productive and successful in the last decade following the invention of PCR technology and the introduction of mitochondrial and microsatellite DNA markers. While mitochondrial DNA has proven powerful for genealogical and evolutionary studies of animal populations, and microsatellite sequences are the most revealing DNA markers available so far for inferring population structure and dynamics, they both have important and unavoidable limitations. To obtain a fuller picture of the history and evolutionary potential of populations, genealogical data from nuclear loci are essential, and the inclusion of other nuclear markers, i.e. single copy nuclear polymorphic (scnp) sequences, is clearly needed. Four major uncertainties for nuclear DNA analyses of populations have been facing us, i.e. the availability of scnp markers for carrying out such analysis, technical laboratory hurdles for resolving haplotypes, difficulty in data analysis because of recombination, low divergence levels and intraspecific multifurcation evolution, and the utility of scnp markers for addressing population-genetic questions. In this review, we discuss the availability of highly polymorphic single copy DNA in the nuclear genome, describe patterns and rate of evolution of nuclear sequences, summarize past empirical and theoretical efforts to recover and analyse data from scnp markers, and examine the difficulties, challenges and opportunities faced in such studies. We show that although challenges still exist, the above-mentioned obstacles are now being removed. Recent advances in technology and increases in statistical power provide the prospect of nuclear DNA analyses becoming routine practice, allowing allele-discriminating characterization of scnp loci and microsatellite loci. This certainly will increase our ability to address more complex questions, and thereby the sophistication of genetic analyses of populations. [ABSTRACT FROM AUTHOR]

Several studies have shown DNA loss to be inversely correlated with genome size in animals. These studies include a comparison between Drosophila and the cricket, Laupala, but there has been no assessment of DNA loss in insects with very large genomes. Podisma pedestris, the brown mountain grasshopper, has a genome over 100 times as large as that of Drosophila and 10 times as large as that of Laupala. We used 58 paralogous nuclear pseudogenes of mitochondrial origin to study the characteristics of insertion, deletion, and point substitution in P. pedestris and Italopodisma. In animals, these pseudogenes are “dead on arrival”; they are abundant in many different eukaryotes, and their mitochondrial origin simplifies the identification of point substitutions accumulated in nuclear pseudogene lineages. There appears to be a mononucleotide repeat within the 643-bp pseudogene sequence studied that acts as a strong hot spot for insertions or deletions (indels). Because the data for other insect species did not contain such an unusual region, hot spots were excluded from species comparisons. The rate of DNA loss relative to point substitution appears to be considerably and significantly lower in the grasshoppers studied than in Drosophila or Laupala. This suggests that the inverse correlation between genome size and the rate of DNA loss can be extended to comparisons between insects with large or gigantic genomes (i.e., Laupala and Podisma). The low rate of DNA loss implies that in grasshoppers, the accumulation of point mutations is a more potent force for obscuring ancient pseudogenes than their loss through indel accumulation, whereas the reverse is true for Drosophila. The main factor contributing to the difference in the rates of DNA loss estimated for grasshoppers, crickets, and Drosophila appears to be deletion size. Large deletions are relatively rare in Podisma and Italopodisma. [ABSTRACT FROM PUBLISHER]

Multiple copies of mitochondrial-like DNA were found in the brown mountain grasshopper, Podisma pedestris (Orthoptera: Acrididae), paralogous to COI and ND5 regions. The same was discovered using the ND5 regions of nine other grasshopper species from four separate subfamilies (Podisminae, Calliptaminae, Cyrtacanthacridinae, and Gomphocerinae). The extra ND5-like sequences were shown to be nuclear in the desert locust, Schistocerca gregaria (Cyrtacanthacridinae), and probably so in P. pedestris and an Italopodisma sp. (Podisminae). Eighty-seven different ND5-like nuclear mitochondrial pseudogenes (Numts) were sequenced from 12 grasshopper individuals. Different nuclear mitochondrial pseudogenes, if descended from the same mitochondrial immigrant, will have diverged from each other under no selective constraints because of their loss of functionality. Evidence of selective constraints in the differences between any two Numt sequences (e.g., if most differences are at third positions of codons) implies that they have separate mitochondrial origins. Through pairwise comparisons of pseudogene sequences, it was established that there have been at least 12 separate mtDNA integrations into P. pedestris nuclear genomes. This is the highest reported rate of horizontal transfer between organellar and nuclear genomes within a single animal species. The occurrence of numerous mitochondrial pseudogenes in nuclear genomes derived from separate integration events appears to be a common phenomenon among grasshoppers. More than one type of mechanism appears to have been involved in generating the observed grasshopper Numts. [ABSTRACT FROM PUBLISHER]

We characterized a novel giant Gypsy-like retrotransposon, Cyclops, present in about 5000 copies in the genome of Pisum sativum. The individual element Cyclops-2 measures 12 314 bp including long terminal repeats (LTRs) of 1504 bp and 1594 bp, respectively, showing 4.1% sequence divergence between one another. Cyclops-2 carries a polypurine tract (PPT) and an unusual primer binding site (PBS) complementary to tRNA-Glu. The element is bounded by 5 bp target site duplications and harbors three successive internal regions with homology to retroviral genes gag (424 codons) and pol (1382 codons) and an additional open reading frame (423 codons) of unknown function indicating the element's potential capacity for gene transduction. The pol region contains sequence motifs related to the enzymes protease, reverse transcriptase, RNAse H and integrase in the same typical order (5′-PR-RT-RH-IN-3′) known for retroviruses and Gypsy-like retrotransposons. The reading frame of the pol region is disrupted by several mutations suggesting that Cyclops-2 does not encode functional enzymes. A phylogenetic analysis of the reverse transcriptase domain confirms our differential genetic assessment that Cyclops from pea is a novel element with no specific relationship to the previously described Gypsy-like elements from plants. Genomic Southern hybridizations show that Cyclops is abundant not only in pea but also in common bean, mung bean, broad bean, soybean and the pea nut suggesting that Cyclops may be an useful genetic tool for analyzing the genomes of agronomically important legumes. [ABSTRACT FROM AUTHOR]

The charge and current quantum zero-point fluctuations in a squeezed vacuum state of a nondissipative mesoscopic capacitance coupling circuit with source are given. The quantum noise of this circuit at absolute zero temperature is derived. It is found that there is a squeezing effect in this coupling circuit. [ABSTRACT FROM AUTHOR]

The control regions of mitochondrial DNA of two insects, Schistocerca gregaria and Chorthippus parallelus, have been isolated and sequenced. Their sizes are 752 by and 1,512 bp, respectively, with the presence of a tandem repeat in C. parallelus. (The sequences of the two repeats are highly conserved, having a homology of 97.5%.) Comparison of their nucleotide sequences revealed the presence of several conserved sequence blocks dispersed through the whole control region, showing a different evolutionary pattern of this region in these insects as compared to that in Drosophila. A highly conserved secondary structure, located in the 3′ region near the small rRNA gene, has been identified. Sequences immediately flanking this hairpin structure rather than the sequences of this structure themselves are conserved between S. gregaria/C. parallelus and Drosophila, having a sequence consensus of 'TATA' at 5′ and 'GAA(A)T' at 3′. The motif 'G(A)nT' is also present in the 3′ flanking sequences of mammalian, amphibian, and fish mitochondrial L-strand replication origins and a potential plant mitochondrial second-strand-replication origin, indicating its universal conservation and functional importance related to replication origins. The stem-and-loop structure in S. gregaria/C. parallelus appears to be closely related to that found in Drosophila despite occupying a different position, and may be potentially associated with a second-strand-replication origin. This in turn suggests that such a secondary structure might be widely conserved across invertebrates while their location in the control region may be variable. We have looked for such a conserved structure in the control regions of two other insects, G. firmus and A. mellifera, whose DNA sequences have been published, and their possible presence is discussed. Mitochondrial control regions characterized to date in five different insect taxa ( Drosophila, G. firmus, A. mellifera, S. gregaria, and C. parallelus) may be classed into two distinct groups having different evolutionary patterns. It is observed that tandem repetition of regions containing a probable replication origin occurred in some species from disjunct lineages in both groups, which would be the result of convergent evolution. We also discuss the possibility of a mechanism of 'parahomologous recombination by unequal crossing-over' in mitochondria, which can explain the generation of such tandemly repeated sequences (especially the first critical repetition) in the control region of mtDNA, and also their convergent evolution in disjunct biological lineages during evolution. [ABSTRACT FROM AUTHOR]

The taxonomic status of the Atlantic and Mediterranean poor cod is a controversial issue. Here we present 10 microsatellite loci from poor cod Trisopterus minutus (L), which have been tested across 10 populations of poor cod. Most loci are highly polymorphic with 7-65 alleles, with one exception, the Tmssr two loci. In poor cod it is a compound microsatellite exhibiting extensive allelic variation. These markers have utility for the two subspecies of poor cod and possible utility for the Trisopterus genus. They may also provide a strong tool for detailed population studies in all gadoids. [ABSTRACT FROM AUTHOR]