bluuebunny/crossref_metadata_2025 huggingface dataset:
Convergent exaptation and adaptation in solitary island lizards
Authors: Poe Steven , Goheen Jacob R , Hulebak Erik P
Published: July 2007

Independent evolutionary lineages often display similar characteristics in comparable environments. Three kinds of historical hypotheses could explain this convergence. The first is adaptive and evolutionary: nonrandom patterns may result from analogous evolutionary responses to shared conditions. The second explanation is exaptive and ecological: species may be filtered by their suitability for a particular type of environment. The third potential explanation is a null hypothesis of random colonization from a historically nonrandom source pool. Here we demonstrate that both exaptation and adaptation have produced convergent similarity in different size-related characters of solitary island lizards. Large sexual size dimorphism results from adaptive response to solitary existence; uniform, intermediate size results from ecological filtering of potential colonizers. These results demonstrate the existence of deterministic exaptive convergence and suggest that convergent phenomena may require historical explanations that are ecological as well as evolutionary.
Travelling on a budget: predictions and ecological evidence for bottlenecks in the annual cycle of long-distance migrants
Authors: Buehler Deborah M , Piersma Theunis
Published: July 2007

Long-distance migration, and the study of the migrants who undertake these journeys, has fascinated generations of biologists. However, many aspects of the annual cycles of these migrants remain a mystery as do many of the driving forces behind the evolution and maintenance of the migrations themselves. In this article we discuss nutritional, energetic, temporal and disease-risk bottlenecks in the annual cycle of long-distance migrants, taking a sandpiper, the red knotCalidris canutus, as a focal species. Red knots have six recognized subspecies each with different migratory routes, well-known patterns of connectivity and contrasting annual cycles. The diversity of red knot annual cycles allows us to discuss the existence and the effects of bottlenecks in a comparative framework. We examine the evidence for bottlenecks focusing on the quality of breeding plumage and the timing of moult as indicators in the six subspecies. In terms of breeding plumage coloration, quality and timing of prealternate body moult (from non-breeding into breeding plumage), the longest migrating knot subspecies,Calidris canutus rogersiandCalidris canutus rufa, show the greatest impact of bottlenecking. The same is true in terms of prebasic body moult (from breeding into non-breeding plumage) which in case of bothC. c. rogersiandC. c. rufaoverlaps with southward migration and may even commence in the breeding grounds. To close our discussion of bottlenecks in long-distance migrants, we make predictions about how migrants might be impacted via physiological ‘trade-offs’ throughout the annual cycle, using investment in immune function as an example. We also predict how bottlenecks may affect the distribution of mortality throughout the annual cycle. We hope that this framework will be applicable to other species and types of migrants, thus expanding the comparative database for the future evaluation of seasonal selection pressures and the evolution of annual cycles in long-distance migrants. Furthermore, we hope that this synthesis of recent advancements in the knowledge of red knot annual cycles will prove useful in the ongoing attempts to model annual cycles in migratory birds.
Adapting to the unpredictable: reproductive biology of vertebrates in the Australian wet–dry tropics
Authors: Shine Richard , Brown Gregory P
Published: July 2007

In the wet–dry tropics of northern Australia, temperatures are high and stable year-round but monsoonal rainfall is highly seasonal and variable both annually and spatially. Many features of reproduction in vertebrates of this region may be adaptations to dealing with this unpredictable variation in precipitation, notably by (i) using direct proximate (rainfall-affected) cues to synchronize the timing and extent of breeding with rainfall events, (ii) placing the eggs or offspring in conditions where they will be buffered from rainfall extremes, and (iii) evolving developmental plasticity, such that the timing and trajectory of embryonic differentiation flexibly respond to local conditions. For example, organisms as diverse as snakes (Liasis fuscus,Acrochordus arafurae), crocodiles (Crocodylus porosus), birds (Anseranas semipalmata) and wallabies (Macropus agilis) show extreme annual variation in reproductive rates, linked to stochastic variation in wet season rainfall. The seasonal timing of initiation and cessation of breeding in snakes (Tropidonophis mairii) and rats (Rattus colletti) also varies among years, depending upon precipitation. An alternative adaptive route is to buffer the effects of rainfall variability on offspring by parental care (including viviparity) or by judicious selection of nest sites in oviparous taxa without parental care. A third type of adaptive response involves flexible embryonic responses (including embryonic diapause, facultative hatching and temperature-dependent sex determination) to incubation conditions, as seen in squamates, crocodilians and turtles. Such flexibility fine-tunes developmental rates and trajectories to conditions–-especially, rainfall patterns–-that are not predictable at the time of oviposition.
Maternal PPARγ protects nursing neonates by suppressing the production of inflammatory milk
Authors: Wan Yihong , Saghatelian Alan , Chong Ling-Wa , Zhang Chun-Li , Cravatt Benjamin F. , Evans Ronald M.
Published: July 2007

Lactation is a highly demanding lipid synthesis and transport process that is crucial for the development of newborn mammals. While PPARγ is known to promote adipogenesis and lipogenesis in adipose tissue, its role in the lactating mammary gland is unexplored. Here, we report that a targeted deletion of PPARγ in mice results in the production of “toxic milk” containing elevated levels of inflammatory lipids. Surprisingly, ingestion of this “toxic milk” causes inflammation, alopecia, and growth retardation in the nursing neonates. Genomic profiling reveals that PPARγ deficiency leads to increased expression of lipid oxidation enzymes in the lactating mammary gland. Consistently, metabolomic profiling detects increased levels of oxidized free fatty acids in the pups nursed by PPARγ-deficient mothers. Therefore, maternal PPARγ is pivotal for maintaining the quality of milk and protecting the nursing newborns by suppressing the production of inflammatory lipids in the lactating mammary gland.
Phenotypic consequences of variation across the aldosterone synthase and 11‐beta hydroxylase locus in a hypertensive cohort: data from the MRC BRIGHT Study
Authors: Freel E. M. , Ingram M. , Friel E. C. , Fraser R. , Brown M. , Samani N. J. , Caulfield M. , Munroe P. , Farrall M. , Webster J. , Clayton D. , Dominiczak A. F. , Davies E. , Connell J. M. C.
Published: July 2007

Background  Aldosterone is an important cardiovascular hormone; 15% of hypertensive subjects have alteration in aldosterone regulation, defined by a raised ratio of aldosterone to renin (ARR). Studies of the aldosterone synthase gene (CYP11B2) have focused on a single nucleotide polymorphism in the 5′promoter region (–344 C/T). In normotensive subjects, the T allele associates with raised levels of the 11‐deoxysteroids, deoxycorticosterone and 11‐deoxycortisol which are substrates for 11β‐hydroxylase, encoded by the adjacent and homologous gene, CYP11B1. We have speculated that this altered 11β‐hydroxylase efficiency leads to increased ACTH drive to the adrenal gland to maintain cortisol production and reported herein the association between the –344 C/T single nucleotide polymorphism (SNP) and adrenal steroid production in subjects with essential hypertension.

Methods  The CYP11B2–344 C/T polymorphism was genotyped and urinary excretion of adrenal steroid metabolites was measured (by GCMS) in 511 unrelated hypertensives from the Medical Research Council (MRC) British Genetics of Hypertension (BRIGHT) study.

Results  Thirty‐five per cent of subjects were homozygous for the –344T allele whilst 16% were CC homozygotes. There was no difference in cortisol excretion rate between the two genotype groups but the index of adrenal 11β‐hydroxylation (ratio of tetrahydrodeoxycortisol/total cortisol) was significantly higher in the TT group (P < 0·005) than in the CC group. Excretion rates of the major urinary metabolite of aldosterone (tetrahydroaldosterone) correlated strongly with the ACTH‐regulated steroids, cortisol (r = 0·437, P < 0·0001) and total androgen metabolites (r = 0·4, P < 0·0001) in TT but not CC subjects.

Conclusions  Hypertensives homozygous for the –344 T allele of CYP11B2 demonstrate altered 11β‐hydroxylase efficiency (CYP11B1); this is consistent with the hypothesis of a genetically determined increase in adrenal ACTH drive in these subjects. The correlation between excretion of aldosterone and cortisol metabolites and suggests that, in TT subjects, ACTH exerts an important common regulatory influence on adrenal corticosteroid production in subjects with hypertension.
Polycystic ovaries and the polycystic ovary syndrome phenotype in women with active acromegaly
Authors: Kaltsas Gregory A. , Androulakis Ioannis I. , Tziveriotis Kostas , Papadogias Dimitrios , Tsikini Aggeliki , Makras Polysois , Dimitriou Konstantina , Stathopoulou Alexandra , Piaditis George
Published: July 2007

Background  Previous retrospective studies have suggested that women with acromegaly may present with menstrual irregularity and symptoms/signs of hyperandogenism, a phenotype similar to that of the polycystic ovary syndrome (PCOS).

Objective  The aim of this study was to investigate prospectively the presence of the PCOS phenotype (PCOSP) and polycystic ovaries (PCO) on ultrasonography in women with active acromegaly.

Design  Women within the reproductive age range (21–43 years) with active acromegaly of recent onset and/or previous surgical and/or medical therapy were studied.

Main outcome measures  Subjects underwent a physical examination; fasting bloods for androgens, pituitary hormones and metabolic parameters; an oral glucose tolerance test (OGTT) to estimate disease activity and insulin resistance; and a transvaginal ultrasound.

Results  Six women had newly diagnosed acromegaly, and eight still had active disease following previous surgical and/or medical treatment. Seven women were found to have PCO and six fulfilled the criteria for PCOSP; six of these women, five with PCOSP, had a pituitary macroadenoma. Women with PCOSP had significantly increased mean ovarian volumes and characteristic ovarian morphology compared to women without PCOSP (P < 0·05), higher levels of IGF‐1 and testosterone and lower SHBG levels that did not reach statistical significance. A positive correlation between IGF‐1 and mean ovarian volume was identified only in women with PCOSP (r = 0·851, P < 0·05).

Conclusions  PCO and PCOSP are relatively common in women with acromegaly and may account for some of the symptoms related to gonadal dysfunction irrespective of the size of the pituitary tumour. It is likely that IGF‐1 alone or in combination with GH and/or insulin resistance may be involved.
Repeated intratunical injection of adenovirus expressing transforming growth factor‐β1 in a rat induces penile curvature with tunical fibrotic plaque: a useful model for the study of Peyronie’s disease
Authors: Piao Shuguang , Ryu Ji‐Kan , Shin Hwa‐Yean , Zhang Luwei , Song Sun U. , Han Jee‐Young , Park Seok Hee , Kim Joon Mee , Kim In‐Hoo , Kim Seong‐Jin , Suh Jun‐Kyu
Published: July 2007

This study was undertaken to establish a Peyronie’s disease model with penile curvature by using recombinant transforming growth factor‐β1 (TGF‐β1) protein or adenovirus (ad‐TGF‐β1). Four‐month‐old male Sprague–Dawley rats were divided into seven groups (n = 18 per group): G1 received a single injection of saline into the tunica albuginea (0.1 mL); G2, repeated injections of ad‐LacZ (days 0, 3, and 6; 1 × 1010 particles/0.1 mL respectively); G3, a single injection of recombinant TGF‐β1 protein (700 ng/0.1 mL); G4, repeated injections of recombinant TGF‐β1 protein (days 0, 3 and 6; 700 ng/0.1 mL respectively); G5, a single injection of low‐dose ad‐TGF‐β1 (1 × 1010 particles/0.1 mL); G6, a single injection of high‐dose ad‐TGF‐β1 (3 × 1010 particles/0.1 mL); and G7, repeated injections of low‐dose ad‐TGF‐β1 (days 0, 3, and 6; 1 × 1010 particles/0.1 mL respectively). Penile curvature was evaluated 30, 45 and 60 days after treatment, and the penis was then harvested for histological examination. Repeated injection of low‐dose ad‐TGF‐β1 not only induced fibrous scar in the tunica, which lasted up to 60 days after injection, but also resulted in significant penile curvature by artificial erection test 45 days after treatment. A peculiar histological finding in this group was trapping of inflammatory cells in the tunica, subsequent fibrosis, and formation of cartilage and calcification as well as loss of elastin fibres. This model involving repeated injection of ad‐TGF‐β1 may contribute to further investigation of the pathogenesis of Peyronie’s disease and the development of new therapeutics targeting this pathway.
Alkali‐labile sites in sperm cells from Sus and Ovis species
Authors: Cortés‐Gutiérrez Elva I. , Dávila‐Rodríguez Martha I. , López‐Fernández Carmen , Fernández José Luis , Gosálvez Jaime
Published: July 2007

Constitutive alkali‐labile sites (ALSs) have been investigated using a protocol of DNA breakage detection–fluorescence in situ hybridization (DBD–FISH) in sperm cells from Sus domesticus (pig), Ovis gmelini musimon (mouflon) and Ovis aries (sheep). The results were compared with those obtained using leucocytes from the same species. Whole comparative genomic hybridization (W‐CGH) showed that most of the constitutive ALSs in somatic and germ line cells in all species examined were constrained to particular repetitive satellite DNA sequences located in the pericentromeric constitutive heterochromatin of each chromosome. However, their relative abundance was different among cells of the same organism (leucocytes/sperm cells), and this trend was not maintained when the different species were compared. Thus, in mouflon, the density of ALSs in leucocytes when compared with that observed in sperm cells indicated abundance of the order of eight times less. In sheep, both leucocytes and sperm cells exhibited a large quantity of ALSs, being of the order of four times more abundant in sperm cells. In the pig genome, leucocytes showed a high abundance of ALSs (of the order of 12 times more that in sperm cells) but only involved the metacentric chromosomes of the karyotype. ALSs were not present in the acrocentric chromosomes. Contrary to mouflon and sheep, ALSs were relatively scarce in sperm cells from pig. These results suggest that ALSs are a transient structural feature in the cells of any organisms and point to a non‐universal model of chromatin organization in sperm cells among mammals.
Localization and expression of spermadhesin PSP‐I/PSP‐II subunits in the reproductive organs of the boar
Authors: García E. M. , Vázquez J. M. , Parrilla I. , Ortega M. D. , Calvete J. J. , Sanz L. , Martínez E. A. , Roca J. , Rodríguez‐Martínez H.
Published: July 2007

The epithelial localization and expression of the spermadhesin PSP‐I and PSP‐II subunits were determined in the testis, ductus epididymes (caput, corpus and cauda), seminal vesicles and bulbourethral glands of mature boars, using immunohistochemical, western blotting and RT‐PCR methods. Immunohistochemistry showed positive labelling for PSP‐I and PSP‐II antibodies in the epithelium of seminal vesicles in all males tested. Positive immunolabelling, but with variable intensity, was also present in the epididymal epithelium (caput, corpus and cauda), although varying largely among segments and boars. Immunoreactivity was nearly or completely absent in the seminiferous epithelium and the bulbourethral gland, although SDS‐PAGE and western blotting revealed the presence of PSP‐I and PSP‐II immunoreactive bands in all the tissue extracts, including the testis and the bulbourethral gland. mRNA amplification by RT‐PCR using primers specific for PSP‐I and PSP‐II showed a trend similar to that observed for western blotting, i.e. intensity variation between tissues (even between segments of the same epididymis) and among boars. Our results indicate that the seminal vesicles are the main source of PSP‐I and PSP‐II spermadhesins, although epididymal segments, testis and the bulbourethral gland also participate in the expression of both proteins.
Dietary selenium deficiency as well as excess supplementation induces multiple defects in mouse epididymal spermatozoa: understanding the role of selenium in male fertility
Authors: Shalini Sonia , Bansal M. P.
Published: July 2007

Selenium (Se) is essential for male fertility. The present study was carried out to observe the defects associated with Se deficiency as well as excess Se supplementation by analyzing the sperm ultrastructure and chromatin organization. Different Se status mice were generated viz. Se deficient (group I), Se adequate (group II) and Se excess (group III) by feeding the respective diets for a period of 4 (group Ia, IIa and IIIa) and 8 weeks (group Ib, IIb and IIIb). Reduction in sperm concentration, motility and percentage fertility was observed in Se deficient and Se excess groups. Electron microscopy revealed mitochondrial swelling and gaps between adjacent mitochondria in mice fed Se‐deficient diet for 4 weeks. At 8 weeks, several abnormalities such as loose contact of the mitochondrial helix with the plasma membrane, loss of mitochondria, retention of cytoplasmic droplet, fracturing of outer dense fibres and presence of both the midpiece and the principal piece cross‐sections in a common plasma membrane were observed. In Se excess group, the predominant defect was the frequent presence of equidistant, cross‐sectioned midpieces of the tail embedded in a common cytoplasm. These defects are indicative of loss of sperm motility. Spermatozoa from Se‐deficient mice had incompletely condensed chromatin and indicated an increase in occurrence of DNA strand breaks. The animals fed Se excess diet also indicated increase in DNA breaks but this was significantly less than the deficient diet fed groups. Our study reveals the defects associated with Se deficiency that result in loss of reproductive ability and also reflects its possible harmful effects on spermatozoa after prolonged consumption at supranutritional level.
Splenic cytokines in mice immunized with testicular germ cells
Authors: Tokunaga Yo , Terayama Hayato , Naito Munekazu , Qu Ning , Hirai Shuichi , Ogawa Yuki , Yi Shuang‐Qin , Itoh Masahiro
Published: July 2007

We previously established that two subcutaneous injections of viable syngeneic testicular germ cells (TGC) alone can induce CD4+ T cell‐dependent experimental autoimmune orchitis (EAO) in mice. This model is histologically characterized by lymphocytic infiltration into the testes and the following aspermatogenesis. In the present study, we investigated the dynamics of splenic cytokines in EAO, using specific enzyme‐linked immunosorbent assay. We found that splenic production of both type 1 helper T cell (Th1) and type 2 helper T cell (Th2)‐related cytokines increased after the second but not the first immunization with TGC, indicating that secondary immune responses are critical to the EAO induction. However, the production of Th1‐related cytokines became predominant at the clinical stage of EAO. Additionally, serum FSH and inhibin‐B increased and decreased, respectively, during EAO. On the other hand, LH did not significantly change and testosterone temporally increased during the same period. These results indicate that both Th1‐ and Th2‐related cytokines are involved at the pre‐clinical phase of EAO, but that Th1‐ rather than Th2‐related cytokines are responsible for the clinical phase when spermatogenesis is disrupted but the Leydig cell function is well preserved.
Morphometric changes in boar spermatozoa induced by cryopreservation
Authors: García‐Herreros M. , Barón F. J. , Aparicio I. M. , Santos A. J. , García‐Marín L. J. , Gil M. C.
Published: July 2007

Computer‐assisted sperm morphometry analysis was used to determine the effects of cryopreservation on boar sperm head and midpiece morphometry. Sperm‐rich fractions were collected from five mature boars. Three microscope slides were prepared from single extended sperm samples prior freezing and post‐thawing. All slides were stained with Hemacolor, and 250 sperm images were obtained from each slide. The sperm head dimensions for length, width, area, perimeter and four shape factors and sperm‐midpiece dimensions for area, width, angle and distance were determined in each spermatozoa. The effects of sperm freezing on sperm dimensions within and among boars were determined. A previous discriminant analysis of the results was able to correctly classify a 78.3 and 82% of fresh and frozen‐thawed spermatozoa respectively. Sperm heads were significantly smaller in cryopreserved spermatozoa than in the companion extended samples for length, width, area and perimeter. Sperm midpieces were also significantly smaller in cryopreserved spermatozoa for width and area. The highest changes in morphometric dimensions after the freeze‐thawing process were found in the midpiece of spermatozoa. The variability of morphometric measurements only was significantly different between fresh and thawed samples for head rugosity and midpiece area. The effects of cryopreservation on morphometric parameters were similar in the boars, which allow us to conclude that cryopreservation process does not have a different effect in each individual boar. In summary, morphometric changes associated with the cryopreservation process on boar spermatozoa do not apparently depends on an effect at individual level.
Prediction of spontaneous conception based on semen parameters
Authors: Jedrzejczak Piotr , Taszarek‐Hauke Grazyna , Hauke Jan , Pawelczyk Leszek , Duleba Antoni J.
Published: July 2007

Accurate prognosis of male fertility based on semen measurements is still not straightforward. This study was designed to identify the best predictors of fertility and to develop a multiple regression model predicting fertility using selected parameters of semen analysis. The predictive value of standard semen parameters and selected functional tests were studied in 113 fertile men and in 109 subfertile men whose spouses had a normal infertility workup. Individual semen parameters were evaluated using the receiver operating characteristic curve. Logistic regression based on linear functions of analysed sperm parameters was used to predict the chance of spontaneous conception. Logistic regression modelling revealed that the best prediction of spontaneous conception was obtained using 12 semen parameters: sperm concentration, total progressive motility (A + B), motility grade C or D, normal sperm morphology, defects of: head, acrosome, midpiece and tail, spontaneous acrosome reaction, hypo‐osmotic swelling (HOS) test and acid aniline blue test. This mathematical model reached 90.3% accuracy in predicting in vivo conception and 90.8% for its lack. A satisfactory prediction of male fertility was also obtained using only four semen measurements: sperm concentration, total progressive motility (grade A + B), normal morphology, and HOS test; this model correctly identified as fertile 84.1% of those who conceived and identified as subfertile 88.1% of those who did not achieve pregnancy. In conclusion, basic semen analysis and selected functional tests of sperm provide important information regarding male fertility status.
Polymorphisms in CYP1A1 gene are associated with male infertility in a Chinese population
Authors: Lu Ningxia , Wu Bin , Xia Yankai , Wang Wei , Gu Aihua , Liang Jie , Lu Chuncheng , Song Lin , Wang Shoulin , Peng Yuzhu , Zhang Zhengdong , Wang Xinru
Published: July 2007

Cytochrome P4501A1 (CYP1A1) is a key enzyme in phase I bioactivation of polycyclic aromatic hydrocarbons (PAHs), which have potential reproductive toxicity. The aim of this study was to investigate the association of the CYP1A1 polymorphisms with male infertility in a Han‐Chinese population. We genotyped two polymorphisms, CYP1A1*2A and CYP1A1*2C, using polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) assay in a hospital‐based case–control study including 192 infertile patients with non‐obstructive azoospermia or severe oligozoospermia and 226 fertile controls. We found that the genotype distribution of CYP1A1*2C was significantly different between the patients and the controls (p = 0.019). Analysis showed that CYP1A1*2C AG genotype was associated with a significantly decreased risk of male infertility [odds ratio (OR) = 0.56, 95% confidence interval (95% CI) = 0.36–0.86, p = 0.005] compared with the AA genotype. A statistically significantly decreased risk of male infertility was found to be associated with the CYP1A1*2C AG genotype plus GG genotype compared with CYP1A1*2C AA genotype (OR = 0.60, 95% CI = 0.40–0.91, p = 0.011). No significant association was detected between CYP1A1*2A polymorphism and male infertility. Haplotypic analysis showed a significantly increased risk of male infertility associated with the C‐A haplotype compared with the T‐A haplotype (OR = 1.98, 95% CI = 1.27–3.09), indicating a synergic effect of the two polymorphisms. Our results suggest that the CYP1A1 polymorphisms may contribute to the pathogenesis of male infertility in the Han‐Chinese population.
Linking agricultural policies to population trends of Swedish farmland birds in different agricultural regions
Authors: WRETENBERG JOHAN , LINDSTRÖM ÅKE , SVENSSON SÖREN , PÄRT TOMAS
Published: July 2007

The widespread declines of farmland birds have generally been linked to agricultural intensification. We tested the hypotheses that (i) changes in agricultural policy, through its effects on agricultural intensification and (ii) regional differences in agricultural intensification affect temporal and spatial population trends of farmland birds in Sweden.

We analysed regional bird population trends (1976–2003) for seven common farmland bird species: the migratory lapwing Vanellus vanellus, skylark Alauda arvensis, starling Sturnus vulgaris and linnet Carduelis cannabina and the resident tree sparrow Passer montanus, house sparrow P. domesticus and yellowhammer Emberiza citrinella. We identified three periods of agricultural policy in Sweden between 1976 and 2003: the intensification period (i.e. 1976–87; promoting increased production), the set‐aside period (1987–95; promoting extensification of farming) and the Common Agricultural Policy (CAP) period (1995–2003; promoting increased production). Population trends were compared between three types of Swedish farmlands: open plains (intensive farming with a marked intensification), mosaic farmlands (i.e. farmland‐dominated forest mosaics, less intensive farming, but show moderate intensification) and forest regions (i.e. forest‐dominated farmlands with low intensity farming and extensification/abandonment).

The four migrants displayed clear significant trend switches between the policy periods, with declines in the ‘intensification period’ and the ‘CAP period’ and less negative or even positive population trends in the ‘set‐aside period’. The population trends of the three resident species showed no clear pattern in relation to agricultural policy periods.

All species except tree sparrow displayed significantly different population trends between farmland regions. Four species (lapwing, skylark, linnet and house sparrow) declined most in the open plains and the forest regions, whereas two species (starling and yellowhammer) declined most in the mosaic farmlands.

Synthesis and applications. Large‐scale changes in agriculture policy have a strong potential to change the present poor state of farmland biodiversity as shown by the generally positive population trends in the ‘set‐aside period’. It also suggests extensification to be beneficial to farmland birds. However, in regions of low profitability and an already ongoing extensification, a further extensification will lead to loss of both farmland habitat and bird diversity. In such regions mixed farming needs to be retained and hence should be supported.
Long‐term effects of human impact on mountainous ecosystems, western Taurus Mountains, Turkey
Authors: Kaniewski D. , De Laet V. , Paulissen E. , Waelkens M.
Published: July 2007

Aim  To investigate the human impact on eastern Mediterranean ecosystems in a subhumid to semi‐arid region of the Near East.

Location  This paper considers data from Bereket (1410–1440 m a.s.l.), an intramontane basin surrounded by the Kokayanık Tepe (1830 m a.s.l.) and the Beşparmak Dağları (2280 m a.s.l.), in the western Taurus Mountains of south‐west Turkey.

Methods  Late Holocene samples were collected along an 800‐cm‐deep sediment profile cored in the secondary valley of the Bereket basin. Descriptive vegetation data and modern pollen samples (moss polsters) were collected at elevational intervals of c. 15 m along an altitudinal transect from the Bereket basin (over Tepe Düzen, 1600 m a.s.l.) to Ağlasun Dağı (1700 m a.s.l.). Information about the spatial distribution of the present land cover was obtained from ASTER satellite imagery. Digital elevation‐derived data and geological information were used to examine the relationship between actual land cover and other environmental variables.

Results  The well dated Bereket sequence provides a unique record of biennial‐to‐decadal landscape changes driven primarily by intensive human impact from 360 cal. yr bc to 650 cal. yr ad. Since 360 cal. yr bc, over‐exploitation of the land has led to altitudinal variation of tree lines, a destruction of the natural forest ecosystems (Pinus–Quercus cerris mixed forest), and an extensive spread of forest‐steppe in the highlands. The present‐day distribution of vegetation in the basin area shows that human activities remain the major factor influencing the character of modern ecosystems.

Main conclusions  This research demonstrates the long‐term local destructive effects of human impacts on the mountainous ecosystems in a small Anatolian intramontane basin since 360 cal. yr bc, and the capacity of these ecosystems to recover during periods of reduced human impact. The late Holocene history and modern vegetation characteristics show that the past and present‐day distribution and composition of vegetation are influenced primarily by human activity, and that substrate, elevation, slope and orientation are of secondary significance.
Glacial refugia for summer‐green trees in Europe and south‐west Asia as proposed by ECHAM3 time‐slice atmospheric model simulations
Authors: Leroy Suzanne A. G. , Arpe Klaus
Published: July 2007

Aim To generate maps of potential refugia for summer‐green trees during the Last Glacial Maximum (LGM).

Locations Southern Europe and south‐western Asia.

Methods Time‐slice simulations of the atmospheric climate with the ECHAM3 model are used for the LGM. Limiting factors beyond which cool and warm groups of deciduous trees cannot grow (such as temperature in growing degree days, minimum monthly temperature and precipitation in summer) are chosen. A limited validation by fossil pollen and charcoal records from LGM sites was done.

Results Two sets of maps extending from Europe to the Caspian region for cool and warm summer‐green trees are presented. Three criteria are combined using contour lines to indicate confidence levels. Small areas within the three southern peninsulas of Europe (Spain, Italy and Greece) are highlighted as possible refugia for summer‐green trees. Further, areas that have remained poorly known are now proposed as refugia, including the Sakarya–Kerempe region in northern Turkey, the east coast of the Black Sea and the area south of the Caspian Sea.

Main conclusions The maps produced in this study could be used to facilitate better long‐term management for the protection of European and south‐western Asian biodiversity.
Systemic oxytocin and vasopressin excite gastrointestinal motility through oxytocin receptor in rabbits
Authors: Li L. , Kong X. , Liu H. , Liu C.
Published: July 2007

Abstract  The aim of the present study was to investigate the effect of systemic oxytocin (OT) and vasopressin (VP) on the motility of stomach and duodenum. Two plastic balloons made of condom were inserted into stomach and duodenum to monitor the change of mean pressure. Intravenous injection of OT (0.1–0.8 μg kg−1) or VP (0.02–0.08 IU kg−1) dose‐dependently increased the stomach and duodenum pressure. Pretreatment of atosiban (1 μg kg−1), the specific OT receptor (OTR) antagonist, attenuated the excitatory effect of OT or VP on the pressure of stomach and duodenum. Pretreatment of V1880 (1 μg kg−1), the specific V1 receptor blocker, did not influence this effect. So we conclude that both of OT and VP injected systemically increased the gastric and duodenum motility via OTR.
Plasticity of synaptic endings in the cochlear nucleus following noise‐induced hearing loss is facilitated in the adult FGF2 overexpressor mouse
Authors: D'Sa Chrystal , Gross Julia , Francone Victor P. , Morest D. Kent
Published: July 2007

In adult mammals a single exposure to loud noise can damage cochlear hair cells and initiate subsequent episodes of degeneration of axonal endings in the cochlear nucleus (CN). Possible mechanisms are loss of trophic support and/or excitotoxicity. Fibroblast growth factor 2 (FGF2), important for development, might be involved in either mechanism. To test this hypothesis, we noise‐exposed FGF2 overexpressor mice and observed the effects on synaptic endings by immunolabelling for SV2, a synaptic vesicle protein, at 1, 2, 4, and 8 weeks after noise exposure. SV2 staining was observed in two major locations; perisomatic, representing axo‐somatic terminals, and neuropil, representing axo‐dendritic terminals. The wildtype (WT) lost both perisomatic and neuropil clusters with an intervening period of modest recovery for the perisomatic. In contrast, in the overexpressor, the perisomatic clusters remained unchanged after intervening periods of increase. The neuropil clusters underwent a period of initial decline, followed by a transient recovery and ultimate decline. Changes in SV2 immunostaining correlated with changes in vesicular glutamate and GABA transporters at synapses and, in the overexpressor, with staining changes for FGF2 and FGF receptor 1. These molecules may contribute to the synaptic reorganization after noise damage; they may protect and/or aid recovery of synapses after overstimulation.
Subventricular zone neuronal progenitors undergo multiple divisions and retract their processes prior to each cytokinesis
Authors: Coskun Volkan , Falls Douglas L. , Lane Richard , Czirok Andras , Luskin Marla B.
Published: July 2007

Mitotically active progenitor cells from the anterior portion of the forebrain subventricular zone (SVZa), which give rise throughout life to olfactory bulb interneurons, bear processes and express neuronal markers. To understand how rodent SVZa neuronal progenitors coordinate division and process formation, we used time‐lapse videomicroscopy to analyse the proliferative behavior of SVZa progenitors in dissociated cell culture continuously for up to five generations. The cell cycle time of these cultured SVZa cells assessed videomicroscopically (cytokinesis to cytokinesis) was similar to the cell cycle time along the rostral migratory stream in vivo (14–17 h). The relationship between process extension, process retraction and cytokinesis was assessed quantitatively for 120 cells undergoing cytokinesis. Although all of these cells had elaborated processes, virtually all of them completely withdrew their processes prior to cytokinesis. Process withdrawal was rapid and tightly coupled to cytokinesis; 50% of the cells studied initiated process retraction within 30 min of cytokinesis and 96% had begun to withdraw their processes within 60 min of cytokinesis. In SVZa progenitor cell lineages, the sequence of process extension, process retraction and division is repeated over multiple generations. This complete withdrawal of processes prior to division differentiates SVZa progenitor cells from the characteristics reported for several other process‐bearing types of neural progenitor cells, including sympathetic neuroblasts, cerebral cortical radial glia, and cerebellar and retinal progenitors. Collectively, our findings indicate that SVZa progenitors employ different cellular mechanisms than other neural progenitors to regulate proliferation and differentiation.
Literacy: a cultural influence on functional left–right differences in the inferior parietal cortex
Authors: Petersson Karl Magnus , Silva Carla , Castro‐Caldas Alexandre , Ingvar Martin , Reis Alexandra
Published: July 2007

The current understanding of hemispheric interaction is limited. Functional hemispheric specialization is likely to depend on both genetic and environmental factors. In the present study we investigated the importance of one factor, literacy, for the functional lateralization in the inferior parietal cortex in two independent samples of literate and illiterate subjects. The results show that the illiterate group are consistently more right‐lateralized than their literate controls. In contrast, the two groups showed a similar degree of left–right differences in early speech‐related regions of the superior temporal cortex. These results provide evidence suggesting that a cultural factor, literacy, influences the functional hemispheric balance in reading and verbal working memory‐related regions. In a third sample, we investigated grey and white matter with voxel‐based morphometry. The results showed differences between literacy groups in white matter intensities related to the mid‐body region of the corpus callosum and the inferior parietal and parietotemporal regions (literate > illiterate). There were no corresponding differences in the grey matter. This suggests that the influence of literacy on brain structure related to reading and verbal working memory is affecting large‐scale brain connectivity more than grey matter per se.
Cajal–Retzius cells and subplate neurons differentially express vesicular glutamate transporters 1 and 2 during development of mouse cortex
Authors: Ina Ayuka , Sugiyama Miki , Konno Jinko , Yoshida Sachine , Ohmomo Hideki , Nogami Haruo , Shutoh Fumihiro , Hisano Setsuji
Published: July 2007

In the light of the various neurobiological effects of glutamate in brain development, although some embryonic cells are a probable source of glutamate involved in the development of precursor cells and/or immature neurons, little is known about when and where glutamate plays its crucial roles during corticogenesis. To investigate these roles, we focused on the developmental expression of vesicular glutamate transporter (VGLUT)1 and VGLUT2, which are regarded as the best markers for verifying glutamatergic neuron identity, especially the spatiotemporal distributions of their transcripts and proteins in the developing mouse cortex and hippocampus. In situ hybridization studies revealed that VGLUT1 mRNA is expressed in preplate and marginal zone cells at embryonic day (E)10 and in subplate cells by E13, whereas VGLUT2 mRNA is expressed in preplate and marginal zone cells at E10 and in cells of the subventricular zone by E13. Reverse transcriptase–polymerase chain reaction analysis detected full‐length VGLUT1 and VGLUT2 gene transcripts in the embryonic brain. By dual labeling combined with immunostaining for microtubule‐associated protein 2 (MAP2) or reelin, we showed that MAP2‐positive preplate and marginal zone neurons and subplate neurons express VGLUT1, while reelin‐positive preplate and marginal zone cells and MAP2‐negative subventricular zone cells express VGLUT2. The present study is the first to provide morphologically reliable evidence showing that Cajal–Retzius cells and subplate neurons are glutamatergic, and that the two cells differentially express VGLUT1 and VGLUT2, respectively, as the specific transport system of glutamate in some events orchestrated by these cells during the cortical development of mice.
Flood Disasters and Agricultural Wages in Bangladesh
Authors: Banerjee Lopamudra
Published: July 2007

This article examines the effects of abnormal floods on agricultural wages in Bangladesh. Drawing upon the district‐wise monthly real wage data for the period 1979–2000, it shows that wages decline sharply in the regions that are severely inundated for a long period of time. Wages may remain depressed in these regions even in the post‐flood months. However, wages increase in the flood months in the regions that remain submerged for short durations. The article examines the district‐wise crop yield data to explain these results in terms of the impact of flood on agricultural productivity, and therefore the demand for labour.
The Political Ecology of Violence in Eastern Sri Lanka
Authors: Bohle Hans‐Georg , Fünfgeld Hartmut
Published: July 2007

In political ecology, violence is usually associated with conflicts over the control of natural resources. Up to now, political ecology has lacked a sound conceptual approach for analysing how violence that has its origin in political conflict induces environmental and social change. This article examines how the environment serves as an arena for exerting power, by using different forms of violence, affecting both ecosystems and the entitlements of the people who are dependent on natural resources. After a brief description of the role of violence in political ecology research, a conceptual framework for a political ecology of violence is laid out. In this framework, the notion of ‘violent environments’ introduced by Nancy Peluso and Michael Watts is blended with new approaches in livelihood research in which the political dimension of livelihood processes is emphasized. Case study material from eastern Sri Lanka, an area affected by prolonged violence and protracted conflict, is presented. This illustrates how violent struggles over environmental entitlements and the politicization of resource‐based livelihoods created alternative systems of power and control over natural resources and triggered new processes of disentitlement and social vulnerability.
Pareto‐optimal Delegation in Customs Unions*
Authors: Melatos Mark , Woodland Alan D.
Published: July 2007

Customs unions constitute agreements to engage in free intra‐union trade and to levy common external tariffs on trade with nonmembers. Existing theoretical models do not agree on how the common external tariffs are chosen. In this paper, a model of customs union formation is developed in which the Pareto principle and the assumption of unanimity are used to construct a mechanism for the choice of common external tariffs. The model is structured as a three‐stage game in which union members select common external tariffs yielding utility outcomes that are Pareto optimal and dominate the standalone alternative. Numerical examples demonstrate the wide range in the nature of these outcomes. Our results are discussed in relation to the delegation principle developed by Gatsios and Karp and to modeling approaches reported in the customs union literature. The paper emphasizes the importance of modeling the formation of the customs union agreement.
Dynamic Games of Environmental Policy in a Global Economy: Taxes versus Quotas
Authors: Yanase Akihiko
Published: July 2007

The effects of environmental policy on the global environment as an international public good with a stock externality and national welfare are examined in a model with trade in a polluting commodity. The welfare effects of environmental policy, decomposed into terms of trade, abatement cost, and environmental damage effects, induce governments to adopt a strategic use of their policy measures. In the absence of international cooperation on environmental policy, it is demonstrated that the emission tax game brings about larger strategic distortions than the emission quota game.
Testing for Error Correction in Panel Data*
Authors: Westerlund Joakim
Published: July 2007

This paper proposes new error correction‐based cointegration tests for panel data. The limiting distributions of the tests are derived and critical values provided. Our simulation results suggest that the tests have good small‐sample properties with small size distortions and high power relative to other popular residual‐based panel cointegration tests. In our empirical application, we present evidence suggesting that international healthcare expenditures and GDP are cointegrated once the possibility of an invalid common factor restriction has been accounted for.
Alteration in brain presenilin‐1 mRNA expression in sporadic Alzheimer's disease
Authors: Isoe‐Wada Kenji , Urakami Katsuya , Wakutani Yosuke , Adachi Yoshidi , Arai Hiroyuki , Sasaki Hidetada , Nakashima Kenji
Published: July 2007

Expression of presenilin‐1 (PS‐1) mRNA in an alternative splicing at the 3' end of exon 3 was examined in brain tissue, lymphocytes and cultured skin fibroblasts using the RT‐polymerase chain reaction (RT‐PCR) method. We quantified the relative ratios of the densities of the long form of PS‐1 mRNA, which contains a sequence encoding four amino acids (VRSQ, denoted as VRSQ+) to the short form, which lacks the VRSQ sequence (VRSQ‐). The brain tissue of subjects with sporadic Alzheimer's disease (AD) had reduced levels of the VRSQS form of the PS‐1 mRNA compared to a control group. No significant differences appeared in peripheral tissues, such as lymphocytes or cultured skin fibroblasts in AD with control subjects. Changes in the alternative splicing of exon 3 may be specific to the brain and may play an important role in the pathogenesis of sporadic AD.
Prophylactic treatment of chronic tension‐type headache using botulinum toxin type A
Authors: Smuts Johan A. , Baker Malcolm K. , Smuts H. Magdalena , Stassen J. M. Rheta , Rossouw Elsabe , Barnard Petronella W. A.
Published: July 2007

Chronic tension‐type headache is a common condition, the pathophysiology of which is not well understood. Over‐activity of the pericranial muscles is thought to play a role, although sustained muscle contraction is probably a consequence, rather than a cause, of headache. Botulinum toxin type A (BTX‐A) is useful in many conditions involving excessive muscle contraction and may therefore be effective in relieving the pain associated with this type of headache. To investigate the efficacy of BTX‐A in relieving pain associated with chronic tension‐type headache, a double‐btind, randomised, placebo‐controlled study was carried out, in which 37 patients received BTX‐A, injected into the temporalis or cervical muscles of the neck. Clinical outcome was measured over a 4‐month study period using headache diaries and chronic pain index scores. Patients treated with BTX‐A showed an improvement in headache severity over the 4‐month study period, with 13 out of 22 patients showing a 25, 50 or >50% improvement in headache score at Month 3 compared with two out of 15 patients in the placebo group. The number of headache‐free days increased significantly in the BTX‐A‐treated patient group, and patients recorded an improvement in quality of life following BTX‐A injection. It can be concluded that intramuscular injection of BTX‐A is an effective treatment for chronic tension‐type headache.