bluuebunny/crossref_metadata_2025_split huggingface dataset:
The historical ecology of the large mammal populations of Ngorongoro Crater, Tanzania, east Africa
Authors: Oates Louise , Rees Paul A. 
Published: April 2012

Abstract
Ngorongoro Crater is an ecologically important protected area in Tanzania, east Africa. We review published and unpublished data on the crater's large mammal community from the first recorded visit by a European in 1892 to 2010.
Early estimates often exaggerated large herbivore numbers and regular scientific censuses have only been made since the 1960s. Since then, most large herbivore populations have declined, particularly wildebeest Connochaetes taurinus, which have been replaced by buffalo Syncerus caffer as the dominant herbivore in terms of biomass. The internationally important population of black rhinoceros Diceros bicornis has reduced from over 100 in the 1960s to around 30 in 2011. The lion Panthera leo population is genetically isolated, has declined since the 1960s and has consistently been held below carrying capacity.
Buffalo and warthogs Phacochoerus aethiopicus are relatively recent colonizers. Wild dogs Lycaon pictus were present in the 1960s but are probably now absent. Small numbers of elephants Loxodonta africana use the crater floor and cheetahs Acinonyx jubatus appear to be intermittent visitors.
Primary drivers of changes in herbivore populations are disease and vegetation change. Poaching has been implicated as the cause of decline in rhinoceros. Disease associated with anomalous weather conditions appears to be the main driver for population change in lions.
Recent scientific research on the large mammal community has largely been focused on lions and rhinoceros. The output of research on other species has not increased since the 1960s.
A wider dissemination of research on the crater's mammal populations would help to secure its status as an important site for conservation in the eyes of the wider scientific and conservation community.
Disruption of gene expression in hybrids of the fire ants Solenopsis invicta and Solenopsis richteri
Authors: OMETTO LINO , ROSS KENNETH G. , SHOEMAKER DeWAYNE , KELLER LAURENT 
Published: April 2012

AbstractTranscriptome analysis is a powerful tool for unveiling the distribution and magnitude of genetic incompatibilities between hybridizing taxa. The nature of such incompatibilities is closely associated with the evolutionary histories of the parental species and may differ across tissues and between the sexes. In eusocial insects, the presence of castes that experience divergent selection regimes may result in additional distinct patterns of caste‐specific hybrid incompatibilities. We analysed levels of expression of >14 000 genes in two life stages of each caste in the fire ants Solenopsis invicta and Solenopsis richteri and in their hybrids. We found strong contributions of both developmental stage and caste to gene expression patterns. In contrast, variability in expression was only weakly associated with taxonomic identity, with hybrid scores falling between those of the two parental species. Hybrid incompatibilities were surprisingly modest, with only 32 genes being mis‐expressed, indicating low levels of disruption in gene regulation in hybrids; males and workers each mis‐expressed at least seven times as many genes as queens. Interestingly, homologues of many of the mis‐expressed genes have been implicated in behavioural variation in Drosophila melanogaster. General expression profiles of hybrids consistently were more similar to those of S. richteri than S. invicta, presumably because S. richteri trans‐regulatory elements tend to be dominant and/or because there is an overall bias in the genetic composition of the hybrids towards S. richteri. Altogether, our results suggest that selection acting on each caste may contribute differently to interspecific divergence and speciation in this group of ants.
Structural assessment of the impact of environmental constraints on Arabidopsis thaliana leaf growth: a 3D approach
Authors: WUYTS NATHALIE , MASSONNET CATHERINE , DAUZAT MYRIAM , GRANIER CHRISTINE 
Published: April 2012

ABSTRACTLight and soil water content affect leaf surface area expansion through modifications in epidermal cell numbers and area, while effects on leaf thickness and mesophyll cell volumes are far less documented. Here, three‐dimensional imaging was applied in a study of Arabidopsis thaliana leaf growth to determine leaf thickness and the cellular organization of mesophyll tissues under moderate soil water deficit and two cumulative light conditions. In contrast to surface area, thickness was highly conserved in response to water deficit under both low and high cumulative light regimes. Unlike epidermal and palisade mesophyll tissues, no reductions in cell number were observed in the spongy mesophyll; cells had rather changed in volume and shape. Furthermore, leaf features of a selection of genotypes affected in leaf functioning were analysed. The low‐starch mutant pgm had very thick leaves because of unusually large palisade mesophyll cells, together with high levels of photosynthesis and stomatal conductance. By means of an open stomata mutant and a 9‐cis‐epoxycarotenoid dioxygenase overexpressor, it was shown that stomatal conductance does not necessarily have a major impact on leaf dimensions and cellular organization, pointing to additional mechanisms for the control of CO2 diffusion under high and low stomatal conductance, respectively.
Effects of flooding on germination and establishment of the invasive cordgrass Spartina densiflora
Authors: ABBAS A M , RUBIO‐CASAL A E , DE CIRES A , FIGUEROA M E , LAMBERT A M , CASTILLO J M 
Published: April 2012

Abbas AM, Rubio‐Casal AE, De Cires A, Figueroa ME, Lambert AM & Castillo JM (2012). Effects of flooding on germination and establishment of the invasive cordgrass Spartina densiflora. Weed Research52, 269–276.SummaryFlooding has been described as one of the most important environmental factors determining the distribution of salt marsh plants. We studied the impact of five water levels (from well‐drained to 8 cm deep) on the germination and establishment of the invasive cordgrass Spartina densiflora under controlled glasshouse conditions. The germination rate was ca. 60%, tending to decrease gradually with depth. There was no seedling emergence from deeper than 4 cm, because every seedling at 8 cm died. Spartina densiflora showed a high physiological plasticity. Seven months after germination, relative water content varied between 69 ± 13% at well‐drained conditions and 87 ± 7% at 4 cm, without significant differences between treatments. Plants rooted at 4 cm presented the highest quantum efficiency of photosystem II (PSII) with slightly lower maximum net photosynthesis rate than other treatments, reflecting high photoprotection levels, together with low nitrogen and pigments contents. Water level depth reduced shoot relative growth rate (RGR). Our results could be useful to fight S. densiflora invasion, because artificial inundation of invaded marshes to a water depth of 8 cm would prevent its establishment from the seed bank.
Basophil response and the induction of a tolerance in venom immunotherapy: a long‐term sting challenge study
Authors: Eržen R. , Košnik M. , Šilar M. , Korošec P. 
Published: April 2012

AbstractBackgroundThere is no in vitro test to predict the induction of long‐term tolerance in patients treated with venom immunotherapy (VIT). The aim of this study was to investigate whether immunotherapy‐induced changes in basophil responsiveness reflect a state of protection and the induction of a tolerance.MethodsTwenty‐three patients with allergic reaction after Hymenoptera sting (11 wasp and 12 honeybee) were treated with VIT. In all patients, a CD63 basophil activation test was performed before the beginning of immunotherapy, after 1 year and after completing 4–6.5 years of immunotherapy (approximately 1 year after stopping). The tolerance was then evaluated by a sting challenge test. The basophil activation test was repeated 3–6 months after the challenge.ResultsTwenty‐two subjects showed a negative sting challenge, and one subject, a positive sting challenge. Allergen‐specific basophil response remained unchanged after 1 year of immunotherapy. However, after immunotherapy, a significant and approximately fourfold decrease was demonstrated in all tolerant subjects mainly in response to submaximal 0.1 μg/ml allergen concentration. This depression was sustained and did not change with the sting challenge test. In a nontolerant patient with a positive sting challenge, basophil response did not change.ConclusionsOur results suggest that the depression of allergen‐specific basophil response seems to be associated with the induction of a tolerance after completing a course of VIT.
Liver transplantation in a child with liver failure due to chronic graft‐versus‐host disease after allogeneic hematopoietic stem cell transplantation from the same unrelated living donor
Authors: Englert C. , Ganschow R. 
Published: April 2012

Englert C, Ganschow R. Liver transplantation in a child with liver failure due to chronic graft‐versus‐host disease after allogeneic hematopoietic stem cell transplantation from the same unrelated living donor.Abstract:  We report a case of a six‐yr‐old boy who developed chronic GVHD of the liver, intestines, and skin following allogeneic hematopoietic SCT. The boy received an allogeneic hematopoietic stem cell transplant at the age of two yr because of early recurrence of ALL. Chimerism analysis showed complete chimerism. In the following year, he developed GVHD despite adequate immunosuppressive therapy. Liver biopsy showed liver GVHD resulting in liver cirrhosis by the age of five yr. LTx was performed with a left liver lobe from the unrelated donor from whom the stem cells had been taken. Immunosuppressive therapy consisted of low‐dose steroids and low‐dose cyclosporine. The postoperative course was uneventful. Graft function was excellent, and we performed protocol biopsies at seven days and three wk as well as three, six, and nine months after transplantation; none of these showed any signs of rejection or GVHD. Immunosuppressive therapy was discontinued nine months after LTx. Three yr after transplantation, the boy is in good condition with normal graft function. To our knowledge, this is the first report on LTx following allogeneic hematopoietic SCT from the same unrelated living donor.
Use it or lose it: reproductive implications of ecological specialization in a haematophagous ectoparasite
Authors: ARBIV A. , KHOKHLOVA I. S. , OVADIA O. , NOVOPLANSKY A. , KRASNOV B. R. 
Published: April 2012

AbstractUsing experimentally induced disruptive selection, we tested two hypotheses regarding the evolution of specialization in parasites. The ‘trade‐off’ hypothesis suggests that adaptation to a specific host may come at the expense of a reduced performance when exploiting another host. The alternative ‘relaxed selection’ hypothesis suggests that the ability to exploit a given host would deteriorate when becoming obsolete. Three replicate populations of a flea Xenopsylla ramesis were maintained on each of two rodent hosts, Meriones crassus and Dipodillus dasyurus, for nine generations. Fleas maintained on a specific host species for a few generations substantially decreased their reproductive performance when transferred to an alternative host species, whereas they generally did not increase their performance on their maintenance host. The results support the ‘relaxed selection’ hypothesis of the evolution of ecological specialization in haematophagous ectoparasites, while suggesting that trade‐offs are unlikely drivers of specialization. Further work is needed to study the extent by which the observed specializations are based on epigenetic or genetic modifications.
The Canalicular System and the Osteoblast Domain in Human Secondary Osteons
Authors: Pazzaglia U. E. , Congiu T. , Marchese M. , Zarattini G. , Dell'Orbo C. 
Published: April 2012

SummaryThe lacunar–canalicular system in human secondary osteons was examined by two complementary techniques: light microscopy analysis of undecalcified thick sections and the SEM cortex‐fractured surface technique. Unlike the earlier definitions of ‘osteoblastic domain’ presented as the matrix volume produced by osteoblasts in the process of osteon infilling, this study measured the domain by the length of osteoblast dendritic processes. The domain extension was defined along radial vectors advancing from the reversal line towards the central canal. According to their lengths, domains were divided into three classes: peripheral, intermediate and internal. The mean length of peripheral domains was significantly shorter than those of the intermediate and internal domains. This suggests that the infilling process is modulated by an initial preparatory phase characterised by osteoblast adhesion to the wall of the cutting cone, and a limited matrix synthesis, followed by a regular matrix volume apposition organised in concentric layers. In addition to the radial canaliculae arranged along converging vectors in planes perpendicular to the central canal, we distinguished a further class of canaliculae, the equatorial canaliculae originating from the major perimeter of the lacuna and spreading out radially in the plane of the same lacuna (therefore, perpendicularly to the radial canaliculae). The whole lacunar–canalicular network was structured as a closed system around the vascular axis of the central canal with very few canaliculae crossing the reversal line and connecting the neighbouring osteons. These anatomical observations contribute to our knowledge of lacunar–canalicular system development.
Female gametogenesis and female gamete germination in the anisogamous green algaCodium fragilesubsp.novae‐zelandiae(Bryopsidophyceae, Chlorophyta)
Authors: Miravalles Alicia B. , Leonardi Patricia I. , Cáceres Eduardo J. 
Published: April 2012

SUMMARYFemale gametogenesis was studied in the dioecious siphonous green algaCodium fragilesubsp.novae‐zelandiae(J. Agardh) P. C. Silva using light and electron microscopy. Early during gametogenesis the protoplasm was uniform; then it separated in portions, while fusiform chloroplasts and nuclei increased in numbers. Some features of the nuclear divisions were similar to those of other Bryopsidophyceae. They were acentric and semi‐open. Pairs of parallel electron‐dense lines resembling synaptonemic complexes were observed in several prophase nuclei indicating meioses. In metaphase the nuclear envelope showed polar fenestrae from which the spindle emerged. No spindle microtubule nucleating material was visible and chromosome kinetochores were evident. Mature female gametes were pyriform with a hyaline anterior end from which the two flagella emerged. Mature gametes had a spherical nucleus surrounded by a mitochondrion and numerous discoid chloroplasts. Female gametes germinated parthenogenetically in culture and also inside gametangia, involving loss of flagella, rounding and lengthening of cells, multiplication of chloroplasts with well developed thylakoid systems, vacuolization and synthesis of a fibrillar cell wall.
Genetic structure of introduced swamp buffalo subpopulations in tropical Australia
Authors: MCMAHON CLIVE R. , ISAGI YUJI , KANEKO SHINGO , BOWMAN DAVID M. J. S. , BROOK BARRY W. , BRADSHAW COREY J. A. 
Published: April 2012

AbstractHigh densities of introduced herbivores can damage sensitive ecosystems, increase the risk of extinction of native biota, and host and spread disease. An essential step in managing large ‘feral’ animal populations is to quantify how they use habitats so that management interventions, such as culling, can be targeted to reduce densities and to minimize migration into areas from which animals have been removed. An effective method to quantify animal movements is by measuring landscape‐scale genetic population structure. We describe the genetic population structure of one of Australia's more destructive introduced mammals – the Asian swamp buffalo (Bubalus bubalis). We collected 524 skin samples from buffalo across their range in the Northern Territory of Australia. Allelic diversity in the Northern Territory population was low compared to those reported from populations in their native Asian habitats. The Australian population is tentatively made of three subpopulations; Melville Island, Eastern Arnhem and Central‐Western Arnhem populations. The Melville Island population is represented by a single cluster, while the Eastern Arnhem population has three clusters and the Central‐Western Arnhem population seven clusters. We found some support for isolation by distance across all the sampled populations, but little evidence for this relationship when comparing the two well‐mixed mainland meta‐populations. Despite their small founder populations and limited genetic variation, the persistence of buffalo in Australia has likely been aided by release from high predation, parasitism and disease typical of their native habitats.
Usefulness of sodium hyaluronate solution in colorectal endoscopic mucosal resection
Authors: Kishihara Teruhito , Chino Akiko , Uragami Naoyuki , Yoshizawa Natsuko , Imai Mizuka , Ogawa Taishi , Igarashi Masahiro 
Published: April 2012

Background:  In endoscopic mucosal resection (EMR), it is essential to inject submucosal fluid to prevent complications and ensure safe and complete en bloc resection of tumors. Sodium hyaluronate (SH) solution, which is effective in forming and maintaining a mucosal lift and is innocuous to mucosal tissue, is considered a useful injection solution for endoscopic submucosal dissection, a procedure associated with a high risk of perforation. This study was undertaken to assess the usefulness of this solution in EMR.Methods:  Ninety‐four patients with colorectal tumors of ≤20 mm in diameter were enrolled for this study and randomized to a SH solution group (0.2% two‐fold diluted MucoUp) or to a normal saline group (control). Ease of EMR was primarily assessed based on ease of submucosal injection, ease of snaring and injection time.Results:  SH solution was superior to normal saline for ease of submucosal injection (57 ± 0.7 vs 50 ± 0.7; P < 0.05), and it showed better results for ease of snaring with less variability (63 ± 0.8 vs 51 ± 1.0; P < 0.05). The mean injection time was similar between the two groups (3.0 ± 9.0 s and 3.0 ± 2.7 s, respectively). Post‐procedural hemorrhage occurred in 7% patients (3/46) injected with SH solution and in 6% of patients (3/48) in the control group; there was no significant difference between the groups.Conclusions:  Use of two‐fold diluted MucoUp facilitated colorectal EMR.
Number of aberrant crypt foci in the rectum is a useful surrogate marker of colorectal adenoma recurrence
Authors: Uchiyama Takashi , Takahashi Hirokazu , Endo Hiroki , Kato Shingo , Sakai Eiji , Hosono Kunihiro , Yoneda Masato , Inamori Masahiko , Hippo Yoshitaka , Nakagama Hitoshi , Nakajima Atsushi 
Published: April 2012

Aim:  Endoscopic screening and removal of colorectal adenomas can reduce the incidence of colorectal cancer. However, given the possibility of adenoma recurrence, surveillance colonoscopy is currently recommended after the initial screening and removal of colorectal adenomas. Aberrant crypt foci (ACF) have been shown to serve as a reliable surrogate marker of colorectal carcinogenesis. In this study, the relationship between the number of ACF at the initial endoscopic polypectomy and the likelihood of colorectal adenoma recurrence after polypectomy were investigated.Methods:  High‐magnification chromoscopic colonoscopy was performed in 82 subjects who underwent endoscopic polypectomy to identify ACF in the lower rectum. Surveillance colonoscopy was then performed 3 years after the baseline polypectomy at Yokohama City University Hospital.Results:  The number of ACF was greater in patients who showed adenoma recurrence (7.88 ± 6.35) than in those who did not (2.19 ± 2.95) (P < 0.001). Receiver–operating curve analysis showed that the number of ACF was a highly specific predictor of the risk of adenoma recurrence.Conclusions:  This is the first study conducted to investigate the relationship between the number of ACF after endoscopic polypectomy and the likelihood of recurrence of colorectal adenomas. These results suggest that the number of ACF is a useful predictor of the likelihood of colorectal adenoma recurrence.
Influence of endoscopic submucosal dissection on serum levels of pepsinogens in patients with early gastric cancer
Authors: Iino Chikara , Shimoyama Tadashi , Sasaki Yoshihiro , Sawaya Manabu , Hanabata Norihiro , Fukuda Shinsaku 
Published: April 2012

Background:  The serum levels of pepsinogens (PG) have been considered to be a useful marker for assessing the risk of metachronous gastric cancer in patients who undergo endoscopic submucosal dissection. However, the influence of endoscopic submucosal dissection (ESD) on serum levels of PG has not yet been examined. The aim of this study was to examine whether the level of PG after ESD can be used to predict the risk of metachronous cancer.Patients and Methods:  The study included of 100 consecutive patients who underwent ESD for gastric cancer at Hirosaki University Hospital from September 2009 to February 2011. Serum levels of PG I and II on the day before and after ESD were compared. Stool antigen test was also performed to examine the presence of Helicobacter pylori infection.Results:  The mean serum level of PG I before and after ESD was 34.3 ± 31.6 ng/mL and 70.5 ± 100.0 ng/mL (P < 0.001), respectively. PG I/II ratio before and after ESD was 2.40 ± 1.51 and 2.79 ± 1.70 (P < 0.001). The serum level of PG I and the PG I/II ratio were significantly changed after ESD, regardless of the use of proton pump inhibitor, Helicobacter pylori infection or the location of the tumor.Conclusions:  ESD treatment modulates the serum level of PG I and significantly increases the PG I/II ratio. Serum levels of PG should be measured before the ESD procedure is performed to predict the risk of developing metachronous gastric cancer after ESD.