bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coevolutionary interactions between host life histories and parasite life cycles
Authors: Koella J. C. , Agnew P. , Michalakis Y. 
Published: March 2011

SummarySeveral recent studies have discussed the interaction of host life-history traits and parasite life cycles. It has been observed that the life-history of a host often changes after infection by a parasite. In some cases, changes of host life-history traits reduce the costs of parasitism and can be interpreted as a form of resistance against the parasite. In other cases, changes of host life-history traits increase the parasite's transmission and can be interpreted as manipulation by the parasite. Alternatively, changes of host's life-history traits can also induce responses in the parasite's life cycle traits. After a brief review of recent studies, we treat in more detail the interaction between the microsporidian parasite Edhazardia aedis and its host, the mosquito Aedes aegypti. We consider the interactions between the host's life-history and parasite's life cycle that help shape the evolutionary ecology of their relationship. In particular, these interactions determine whether the parasite is benign and transmits vertically or is virulent and transmits horizontally.Key words: host-parasite interaction, life-history, life cycle, coevolution.
The biology ofPlasmodium falciparumtransmission stages
Authors: Day K. P. , Hayward R. E. , Dyer M. 
Published: March 2011

SummaryThe most important function of any parasite is to secure transmission to new hosts. The gametocyte, the stage which has become developmentally committed to the sexual cycle, provides a critical link in the transmission ofPlasmodium falciparumfrom the human host to the anopheline mosquito vector. It is therefore imperative that our determination to understand the biology of the gametocyte is greater than the technical obstacles which have resulted in the gametocyte being left very much out of the limelight by the intensive investigation of the asexual bloodstream parasite. Here we explore the areas of gametocyte biology which by nature of their relevance to control and pathology as well as basic biology, are the subjects of investigation in our laboratory. We also point out areas in need of particular attention.
Wolbachiaas a possible means of driving genes into populations
Authors: Curtis C. F. , Sinkins S. P. 
Published: March 2011

SummaryCytoplasmic incompatibility consists of sterility in cross matings, the crossing type being maternally inherited. It can be explained by the action ofWolbachiasymbionts which are transmitted through the egg cytoplasm and leave an imprint on the sperm which prevents it fertilizing unless it is ‘rescued’ by the action of the same type ofWolbachiain the egg. Thus matings between infected males and uninfected females are sterile, but the reciprocal matings are fertile. Hence uninfected females are at risk of failing to transmit their uninfected cytoplasm if they cross mate, but infected females are at no such risk. Therefore natural selection favours the infected state and in two wild insect populations the infection has been observed spreading. If a gene for inability to transmit malaria could be introduced intoWolbachiaand if this could be introduced intoAnopheles(where these symbionts appear not to occur naturally), release of a limited number of such insects should trigger a process of displacement of malaria vectors, by the non-vector type. A simple model is used to demonstrate the limitations to this process which would be introduced by immigration.
Optimal habitat selection by helminths within the host environment
Authors: Sukhdeo M. V. K. , Sukhdeo S. C. 
Published: March 2011

SUMMARYHelminth parasites of vertebrates usually select very specific regions or habitats in their hosts, and this is often preceded by a tortuous migration through various host organs. However, the proximate mechanisms of migration and habitat selection have remained enigmatic despite considerable effort by parasitologists. In this paper, a new approach to studying helminth behaviour in the host is proposed. The core idea is that behaviour strategies must be considered from the perspective of the parasites and their perceptions of their environment. A guiding principle is that the environmental features to which an animal responds, and the actions which are required for responding to the environment, form a fundamental unit of behaviour. Thus, we can deduce an animal's behavioural strategy from the details of its response to environmental signals and from its sensory capabilities. The evidence presented suggests that helminth behaviours in the host often occur as fixed (or modal) action patterns which are usually seen in response to constant, or predictable environmental features. Thus, a working hypothesis is that the mechanisms of physiological and biochemical homeostasis within the host provide an extremely predictable environment for the parasite. Under these conditions, a parasite needs to perceive only small subsets of the total information available from the environment to respond appropriately. Studies on sensory and nervous systems of these organisms are critical to understanding parasite perception, but there are formidable technical obstacles that prevent easy access to parasite nervous systems. Therefore, a multidisciplinary approach, using ideas from parasitology, ecology, evolutionary biology and neuroethology, is considered requisite for reconstructing the parasites' behaviour strategies. It is suggested that future directions should pursue integration of studies on sensory physiology with the behavioural ecology of these organisms.
Evolutionary factors influencing the nature of parasite specificity
Authors: Adamson M. L. , Caira J. N. 
Published: March 2011

SUMMARYThis article considers how specificity patterns are shaped during the course of parasite evolution. Parasites are first and foremost specific to site, or microhabitat; host ranges are far more subject to change than is microhabitat. Specificity results from a number of convergent phenomena starting with habits (microhabitat and feeding styles) of free-living progenitors and the way in which the parasitic association arises (e.g., passive oral contamination as opposed to intrusive entry). These bias the types of interaction parasites have with the host, and, through this, the way specificity develops. Host ecology acts as an external factor affecting specificity and predominates in parasites that interact minimally with the hosts physiological and immune systems. Coevolutionary factors are more important in parasites that feed on host tissues or occur in extraintestinal sites. Here, parasites must present the right cues, and respond appropriately to the host defense system. The ability to generalize these cues and responses across host boundaries may act as a constraint on host range. The functional role of the host in the parasite life history also affects the degree of specificity; thus, parasites may act as host generalists in hosts that act as trophic channels to the final host. The role of competition in determining specificity is difficult to assess. However, competition has been reported to influence microhabitat and host distribution through interactive site selection and/or competitive seclusion.
Physiological bases for parasite-induced alterations of host behaviour
Authors: Thompson S. N. , Kavaliers M. 
Published: March 2011

SUMMARYParasitism is defined in various ways as an intimate relationship in which one partner, the parasite, lives on or in another, the host, generally at the expense of the latter. Parasitism commonly results in a unique array of host physiological responses and adaptations. Most studies of the physiological effects of parasitism have focused on the pathological consequence of infection and disease. While many physiological changes contribute to pathogenesis, it is now recognized that parasitic infections at sub-clinical levels also produce physiological effects that either ameliorate or may not contribute to the disease process. Moreover, these physiological changes are often manifested by altered host behaviour. Behavioural studies have enabled an ecological- and evolutionary-oriented evaluation of host responses. In this fashion, physiological effects may be assessed as to whether they affect fitness and confer benefit or harm to one or both of the symbionts involved. We briefly examine how these physiological responses, specifically neural, endocrine, neuromodulatory, and immunomodulatory components, may interact to modify host behaviours. We consider the adaptiveness of these responses and how the behavioural patterns elicited may simultaneously appear adaptive for the parasite as well as the host. In addition, we address how parasite-host physiological and behavioural interactions may be altered during the course of parasitism.
Effects of different cryopreservation methods on post-thaw culture conditions of in vitro produced bovine embryos
Authors: Nicacio Alessandra Corallo , Simões Renata , de Paula-Lopes Fabiola Freitas , de Barros Flavia Regina Oliveira , Peres Maria Angelica , Assumpção Mayra Elena Ortiz D'Avila , Visintin Jose Antonio 
Published: March 2011

SummaryThe aim of this work was to evaluate the effect of cryopreservation protocols on subsequent development of in vitro produced bovine embryos under different culture conditions. Expanded in vitro produced blastocysts (n = 600) harvested on days 7–9 were submitted to controlled freezing [slow freezing group: 10% ethylene glycol (EG) for 10 min and 1.2°C/min cryopreservation]; quick-freezing [rapid freezing group: 10% EG for 10 min, 20% EG + 20% glycerol (Gly) for 30 s]; or vitrification [vitrification group: 10% EG for 10 min, 25% EG + 25% Gly for 30 s] protocols. Control group embryos were not exposed to cryoprotectant or cryopreservation protocols and the hatching rate was evaluated on day 12 post-insemination. In order to evaluate development, frozen–thawed embryos were subjected to granulosa cell co-culture in TCM199 or SOFaa for 4 days. Data were analyzed by PROC MIXED model using SAS Systems for Windows®. Values were significant at p < 0.05. The hatching rate of the control group was 46.09%. In embryos cultured in TCM199, slow freezing and vitrification group hatching rates were 44.65 ± 5.94% and 9.43 ± 6.77%, respectively. In embryos cultured in SOFaa, slow freezing and vitrification groups showed hatching rates of 11.65 ± 3.37 and 8.67 ± 4.47%, respectively. In contrast, the rapid freezing group embryos did not hatch, regardless of culture medium. The slow freezing group showed higher hatching rates than other cryopreservation groups. Under such conditions, controlled freezing (1.2°C/min) can be an alternative to cryopreservation of in vitro produced bovine embryos.
Participation in communication and decision‐making: children and young people’s experiences in a hospital setting
Authors: Coyne Imelda , Gallagher Pamela 
Published: March 2011

Aim.  To explore hospitalised children and young people’s experiences of participation in communication and decision‐making.Background.  There is a growing recognition internationally that children and young people have a right to participate in matters that affect their lives. Although this has led to more support for children’s participation in communication exchanges and decision‐making in health care, there remains a lack of studies in this area.Design.  Qualitative.Method.  Data were obtained through a combination of focus groups and single interviews with participants aged 7–18 (n = 55), from three hospitals in Ireland.Results.  Children wanted to be included in communication exchanges but appeared to occupy a marginal role with discussions largely carried out between parents and health professionals. They wanted to participate in ‘small’ everyday decisions about their care and treatment but were constrained mainly by adults’ actions.Conclusion.  Although children want to be included in the decision‐making process, some prefer to leave the more ‘serious’ decisions to parents and health professionals, whilst others prefer to share the decision. Children’s preferences can vary; therefore, decision‐making should be seen as being on a continuum rather than an ‘all or nothing’ basis.Relevance to clinical practice.  Health care professionals and parents appear to play a significant role on whether children’s efforts to participate are facilitated and supported in the hospital setting. Clearly, some may have reservations/concerns about children’s participation, which suggests the need for clear guidelines/policies that reflect all stakeholder views. Children should be supported in having their voices heard in matters that directly affect their lives.
Induction of ferredoxin‐NADP+ oxidoreductase and ferredoxin synthesis in pea root plastids during nitrate assimilation
Authors: Bowsher C.G. , Hucklesby D.P. , Emes M.J. 
Published: March 2011

SummaryA 14.5 kDa protein with antigenic components in common with pea leaf ferredoxin was detected on transblots of the soluble proteins of pea root plastids. The amount of this protein was found to increase during the induction of nitrate assimilation in pea roots, reaching a maximal level at 8–12 h. Concurrent with this, a fourfold increase in NADPH‐dependent ferredoxin‐NADP+ oxidoreductase (FNR) activity was observed corresponding to an increase in the amount of this protein detected immunologically on transblots using a leaf FNR antibody. These changes were not observed in plastids from roots of plants grown on ammonia or depleted of nitrogen. It is suggested that in addition to the already well reported induction by nitrate of nitrate reductase and nitrite reductase, there is a co‐induction of a plastid located ferredoxin and FNR. Both these proteins are necessary for the transfer of reductant generated by the oxidative pentose phosphate pathway to nitrite reductase.
Conserved regulation of the soybean early nodulin ENOD2 gene promoter in determinate and indeterminate transgenic root nodules
Authors: Lauridsen Peter , Franssen Henk , Stougaard Jens , Bisseling Ton , Marcker Kjeld A. 
Published: March 2011

SummaryThe β‐glucuronidase (GUS) activity expressed from the soybean early nodulin ENOD2(B) gene promoter was localized histochemically in nodules of Lotus corniculatus and Trifolium repens. In both the determinate Lotus nodules and the indeterminate Trifolium nodules, activity was found in the parenchyma cells and especially in cells close to the vascular tissue of nodules. The characteristic cell‐specific expression of the soybean ENOD2 gene was therefore maintained by the ENOD2(B) promoter in the two developmentally different nodule types. Important DNA elements recognized in transgenic nodules were identified by deletion and hybrid promoter analysis in Lotus ***corniculatus. An indispensable positive element (PE) and a possible tissue specific element was defined between positions −1792 and −1582 from the transcription start site. Another qualitative control element located between −380 and −53 conferred the ENOD2 characteristic cell type expression on hybrid promoters. This element contains the conserved nodulin gene sequences CTCTT and AAAGAT.In contrast to the ENOD2(B) promoter a chimeric leghemoglobin lbc3‐GUS gene was expressed in the infected cells of both types of nodules. In the indeterminate nodules expression was restricted to the interzone II‐III and the active nitrogen‐fixing zone III. Interchange of the distal strong positive element (SPE) of lbc3 and the ENOD2 positive element resulted in an expression pattern different from that observed for the lbc3 and ENOD2 genes, indicating that different interactions of trans‐acting factors are required for regulation of early as well as late nodulin genes.
Consequences of floral visits by ants and invasive honeybees to the hummingbird‐pollinated, Caribbean cactus Melocactus intortus
Authors: FAGUA J. CAMILO , ACKERMAN JAMES D. 
Published: March 2011

AbstractThe pink, tubular, nectariferous flowers of Melocactus intortus (Cactaceae) in Puerto Rico are visited by native hummingbirds (Anthracothorax dominicus), but also by invasive honeybees (Apis mellifera) and ants (Solenopsis sp.). We sought to determine if the bees and ants significantly alter the pollination of M. intortus by measuring pollinator effectiveness. Using traditional estimates of effectiveness (visitation rate and seed set), our results show that hummingbirds were the most effective pollinators as expected. Bees and ants were less effective, and their contributions were one‐fourth to one‐tenth of that observed for hummingbirds. We then modified this measure of effectiveness by adding two components, fitness of progeny and temporal availability of visitors, both of which refine estimates of flower visitor effectiveness. With these new estimations, we found that the effectiveness values of all three animal visitors decreased; however, the role of hummingbirds as the principal pollinator was maintained, whereas the effectiveness values of bees and ants approached zero. By these new measures of overall pollinator effectiveness, the invasive honeybees and ants have little effect on the reproductive success of M. intortus.
Vitamin B12 biosynthesis gene diversity in the Ross Sea: the identification of a new group of putative polar B12 biosynthesizers
Authors: Bertrand Erin M. , Saito Mak A. , Jeon Young Jae , Neilan Brett A. 
Published: March 2011

SummaryVitamin B12, a cobalt‐containing micronutrient, has been shown to limit phytoplankton growth in the Ross Sea of the Southern Ocean. However, B12 biosynthesis potential in this environment remains uncharacterized. Select bacteria and archaea synthesize B12 while many phytoplankton require it for growth. Low ratios of bacterial biomass production to primary productivity and high concentrations of labile cobalt in Antarctic surface water suggest that factors controlling bacterial growth rather than cobalt availability may determine vitamin production rates here. In order to assess B12 biosynthesis potential, degenerate polymerase chain reaction primers were designed to target the genetic locus cbiA/cobB, encoding cobyrinic acid a,c‐diamide synthase, a B12 biosynthesis protein. Sequencing the DNA compliment of Ross Sea 16S rRNA (see Supporting information) allowed targeting of cbiA/cobB probes to dominant bacterial groups. CbiA/cobB DNA sequences were successfully identified in clone libraries from the Ross Sea. To our knowledge, this study represents the first targeted molecular characterization of environmental B12 biosynthesis potential. A newly identified group of cbiA/cobB sequences dominated the diversity of the sequences retrieved; their expression was confirmed via mass spectrometry‐based peptide detection. These sequences seem to have originated from a previously undescribed group of bacteria that could dominate the B12 biosynthesizing community in polar systems.
Complications during the initial experience with laparoendoscopic single‐site pyeloplasty
Authors: Best Sara L. , Donnally Chester , Mir Saad A. , Tracy Chad R. , Raman Jay D. , Cadeddu Jeffrey A. 
Published: March 2011

Study Type – Therapy (case series)Level of Evidence 4What’s known on the subject? and What does the study add?Laparoendoscopic single‐site surgery (LESS) can provide cosmetic advantages to patients. However, LESS pyeloplasty and other reconstructive procedures pose substantial technical challenges compared to traditional laparoscopy. The impact these challenges have on the learning curves of these operations is incompletely understood.This investigation reviews the initial experience of an experienced laparoscopist over the first 28 cases of LESS pyeloplasty he performed, providing insight into the learning curve as reflected by changes in operative time and post‐operative complications over time.OBJECTIVE• To review our initial series of laparoendoscopic single‐site (LESS) pyeloplasties, focusing on 30‐day complication rates as an indicator of learning curve, and to define the expected morbidity.PATIENTS AND METHODS• The study comprised 28 patients who underwent LESS pyeloplasty by a single surgeon from October 2007.• A chart review was undertaken to identify the complications that occurred within the first 30 days after surgery.RESULTS• The mean operating time was 197 min.• Seven patients (25%) experienced a total of eight complications. Four patients required nephrostomy tube placement (14%) during the early postoperative period, two for symptomatic obstruction despite the ureteral stent and two for a urine leak. Another had urine leakage that resolved spontaneously after she went home with the surgical drain for 1 week. One patient (4%) developed a retroperitoneal haematoma and required blood transfusion and one had haematuria that prolonged hospital stay by 2 days.• Of the patients experiencing complications, 71% were in the first ten cases. Only two complications occurred in the subsequent 18 patients.CONCLUSIONS• The LESS pyeloplasty procedure is a technically difficult, even for an experienced laparoscopic surgeon and the surgical challenges of this technique may translate to a higher complication rate for LESS than for conventional laparoscopic pyeloplasty early in the learning curve. However, within a relatively few cases, the complication rate is similar to that of standard laparoscopic pyeloplasty.• Additional follow‐up is required to determine the long‐term success rate.
Treatment decision‐making in localized prostate cancer: why patients chose either radical prostatectomy or external beam radiation therapy
Authors: Ihrig Andreas , Keller Monika , Hartmann Mechthild , Debus Jürgen , Pfitzenmaier Jesco , Hadaschik Boris , Hohenfellner Markus , Herzog Wolfgang , Huber Johannes 
Published: March 2011

Study Type – Therapy (case series)Level of Evidence 4What’s known on the subject? and What does the study add?Our patients’ personal preferences are of major importance for decision‐making in localized prostate cancer. The study evaluates strategies in choosing either RP or EBRT. Typical modes of reasoning consist of personal beliefs in patients choosing RP and fear of treatment related side‐effects in the EBRT group.OBJECTIVES• To evaluate patients’ treatment decision‐making for localized prostate cancer.• To determine their willingness to participate in a randomized controlled trial (RCT) comparing radical prostatectomy (RP) with external beam radiation therapy (EBRT).PATIENTS AND METHODS• We investigated 31 patients with localized prostate cancer who had opted for either RP (n= 18) or EBRT (n= 13) as primary therapy.• A semi‐structured interview and a short questionnaire were completed a few days after the start of treatment, covering all aspects of treatment decision.RESULTS• Most patients wanted to decide on their treatment together with their physician and were generally satisfied with the information provided. Internet resources were used more frequently by the RP group (14/18 patients) than by the EBRT group (three of 13 patients, P < 0.01).• Physicians’ advice and other patients’ experiences were highly influential in the final treatment decisions.• Patients deciding on RP were younger and their personal beliefs were their typical decision criteria (RP, six of 18 patients vs EBRT, none; P= 0.03). By contrast, possible treatment‐related side‐effects were a major concern for patients choosing EBRT (RP, two of 18, vs EBRT, seven of 14; P= 0.02).• Only two patients (of 31, 6%) would have consented to random assignment to either RP or EBRT, while six (19%) patients were not averse.CONCLUSIONS• Patients are satisfied with the information provided and with their decision‐making process.• Typical modes of reasoning can be found and mainly consist of personal beliefs in patients choosing RP and fear of treatment related side‐effects in those choosing EBRT.• According to the sample, the participation rate for a RCT comparing RP to EBRT would not exceed 25% without further efforts.