bluuebunny/crossref_metadata_2025_split huggingface dataset:
Agglomerating seeds to enhance native seedling emergence and growth
Authors: Madsen Matthew D. , Davies Kirk W. , Williams C. Jason , Svejcar Tony J. 
Published: March 2012

Summary1. Restoration in rangelands is constrained by low establishment of species sown from seed. Non‐biotic soil‐surface crust is one of the major factors limiting reseeding success by acting as a barrier to seedling emergence.2. The objective of this study was to determine whether seedling emergence could be improved by agglomerating multiple seeds into a single pellet, so that the seedlings growing from the pellet will collectively generate sufficient force to penetrate the soil crust. To evaluate this technology, we compared seedling emergence and biomass production from agglomerated, single and non‐coated seed (control) of Pseudoroegneria spicata. In the greenhouse, seeds were sown in either crust‐forming clay or non‐crusting sandy soil and studied for a 25‐day period. Starting seed density was constant across treatments.3. In the clay soil, seedling emergence from the agglomeration treatment was 1·3 and 1·9 times higher than the single seed coating and control, respectively. In the sandy soil, the agglomeration and single seed coating responded similarly, producing 1·4 times more seedlings than the control.4. Biomass production followed a similar trend as plant density. In the clay soil, increased biomass of the agglomeration treatment was not only because of higher plant densities but was also a product of having greater biomass per plant.5. Synthesis and applications. This short‐duration ‘proof‐of‐concept’ study indicates that both the seed coating materials used to form the agglomerates and the act of agglomerating the seeds together improve P. spicata emergence and plant growth. These results also demonstrate that in the early seedling stage, facilitation outweighs competition in agglomeration plantings. Additional research is needed to verify these results in the field.
Managing fire mosaics for small mammal conservation: a landscape perspective
Authors: Kelly Luke T. , Nimmo Dale G. , Spence‐Bailey Lisa M. , Taylor Rick S. , Watson Simon J. , Clarke Michael F. , Bennett Andrew F. 
Published: March 2012

Summary1. Fire is a major driver of ecosystem structure and function worldwide. It is also widely used as a management tool to achieve conservation goals. A common objective is the maintenance of ‘fire mosaics’ comprising spatially heterogeneous patches of differing fire history. However, it is unclear what properties of fire mosaics most enhance conservation efforts. Here we focus on the spatial and temporal properties of fire‐prone landscapes that influence the distribution of small mammals.2. We surveyed small mammals in 28 landscapes (each 12·6 km²) representing a range of fire histories in the Murray Mallee region (104 000 km²) of semi‐arid Australia. Generalised linear mixed models were used to examine the influence of five landscape properties on the capture rate of individual species and the species richness of native small mammals. We investigated the influence of the proportional extent of fire age‐classes, the diversity of fire age‐classes, the extent of the dominant vegetation type, rainfall history and biogeographic context.3. Three of four study species were associated with the spatial extent of fire age‐classes. Older vegetation was found to provide important habitat for native small mammals. Overall, however, rainfall history and biogeographic context were dominant influences: for example, the species richness of native mammals was positively associated with above‐average rainfall. There was little evidence that the diversity of fire age‐classes influenced either the capture rate of individual species or species richness.4. Synthesis and applications. In fire‐prone environments, habitat availability can change markedly over short time‐scales. Sufficient habitat at a suitable seral stage within the landscape is a key requirement for species conservation. In mallee ecosystems, the retention of older vegetation is recommended to create more desirable fire mosaics for native small mammals. In addition to such spatial properties of mosaics that are amenable to manipulation, an understanding of how ecological processes affect the biota (such as variation in rainfall‐driven productivity) is also essential for informed conservation management.
Using functional traits and phylogenetic trees to examine the assembly of tropical tree communities
Authors: Baraloto Christopher , Hardy Olivier J. , Paine C. E. Timothy , Dexter Kyle G. , Cruaud Corinne , Dunning Luke T. , Gonzalez Mailyn‐Adriana , Molino Jean‐François , Sabatier Daniel , Savolainen Vincent , Chave Jerome 
Published: March 2012

Summary1. Niche theory proposes that species differences underlie both coexistence within communities and the differentiation in species composition among communities via limiting similarity and environmental filtering. However, it has been difficult to extend niche theory to species‐rich communities because of the empirical challenge of quantifying niches for many species. This has motivated the development of functional and phylogeny‐based approaches in community ecology, which represent two different means of approximating niche attributes.2. Here, we assess the utility of plant functional traits and phylogenetic relationships in predicting community assembly processes using the largest trait and phylogenetic data base to date for any set of species‐rich communities.3. We measured 17 functional traits for all 4672 individuals of 668 tree species co‐occurring in nine tropical rain forest plots in French Guiana. Trait variation was summarized into two ordination axes that reflect species niche overlap.4. We also generated a dated molecular phylogenetic tree based on DNA sequencing of two plastid loci (rbcLandmatK) comprising 97% of the individuals and 91% of the species in the plots.5. We found that, on average, co‐occurring species had greater functional and, to a lesser extent, phylogenetic similarity than expected by chance.6. We also found that functional traits and their ordination loadings showed significant, albeit weak, phylogenetic signal, suggesting that phylogenetic distance provides pertinent information on niche overlap in tropical tree communities.7. Synthesis. We provide the most comprehensive examination to date of the relative importance of environmental filtering and limiting similarity in structuring tropical tree communities. Our results confirm that environmental filtering is the overriding influence on community assembly in these species‐rich systems.
Helium ion microscopy for high‐resolution visualization of the articular cartilage collagen network
Authors: VANDEN BERG‐FOELS W.S. , SCIPIONI L. , HUYNH C. , WEN X. 
Published: March 2012

SummaryThe articular cartilage collagen network is an important research focus because network disruption results in cartilage degeneration and patient disability. The recently introduced helium ion microscope (HIM), with its smaller probe size, longer depth of field and charge neutralization, has the potential to overcome the inherent limitations of electron microscopy for visualization of collagen network features, particularly at the nanoscale. In this study, we evaluated the capabilities of the helium ion microscope for high‐resolution visualization of the articular cartilage collagen network. Images of rabbit knee cartilage were acquired with a helium ion microscope; comparison images were acquired with a field emission scanning electron microscope (FE‐SEM) and a transmission electron microscope (TEM). Sharpness of example high‐resolution helium ion microscope and field emission scanning electron microscope images was quantified using the 25–75% rise distance metric. The helium ion microscope was able to acquire high‐resolution images with unprecedented clarity, with greater sharpness and three‐dimensional‐like detail of nanoscale fibril morphologies and fibril connections, in samples without conductive coatings. These nanoscale features could not be resolved by field emission scanning electron microscopy, and three‐dimensional network structure could not be visualized with transmission electron microscopy. The nanoscale three‐dimensional‐like visualization capabilities of the helium ion microscope will enable new avenues of investigation in cartilage collagen network research.
Perceived poor sleep quality in the absence of polysomnographic sleep disturbance in women with severe premenstrual syndrome
Authors: BAKER FIONA C. , SASSOON STEPHANIE A. , KAHAN TRACEY , PALANIAPPAN LATHA , NICHOLAS CHRISTIAN L. , TRINDER JOHN , COLRAIN IAN M. 
Published: March 2012

SummaryWomen with severe premenstrual syndrome report sleep‐related complaints in the late‐luteal phase, but few studies have characterized sleep disturbances prospectively. This study evaluated sleep quality subjectively and objectively using polysomnographic and quantitative electroencephalographic measures in women with severe premenstrual syndrome. Eighteen women with severe premenstrual syndrome (30.5 ± 7.6 years) and 18 women with minimal symptoms (controls, 29.2 ± 7.3 years) had polysomnographic recordings on one night in each of the follicular and late‐luteal phases of the menstrual cycle. Women with premenstrual syndrome reported poorer subjective sleep quality when symptomatic in the late‐luteal phase compared with the follicular phase (P < 0.05). However, there were no corresponding changes in objective sleep quality. Women with premenstrual syndrome had more slow‐wave sleep and slow‐wave activity than controls at both menstrual phases (P < 0.05). They also had higher trait‐anxiety, depression, fatigue and perceived stress levels than controls at both phases (P < 0.05) and mood worsened in the late‐luteal phase. Both groups showed similar menstrual‐phase effects on sleep, with increased spindle frequency activity and shorter rapid eye movement sleep episodes in the late‐luteal phase. In women with premenstrual syndrome, a poorer subjective sleep quality correlated with higher anxiety (r = −0.64, P = 0.005) and more perceived nighttime awakenings (r = −0.50, P = 0.03). Our findings show that women with premenstrual syndrome perceive their sleep quality to be poorer in the absence of polysomnographically defined poor sleep. Anxiety has a strong impact on sleep quality ratings, suggesting that better control of mood symptoms in women with severe premenstrual syndrome may lead to better subjective sleep quality.
The csgD mRNA as a hub for signal integration via multiple small RNAs
Authors: Boehm Alex , Vogel Jörg 
Published: March 2012

SummaryThe transcription factor CsgD governing the production of curli fimbriae and cellulose is a key player in the complex regulatory circuit that decides whether Escherichia coli form biofilms. The csgD gene itself is tightly controlled at the level of transcription by a large array of DNA‐binding proteins, but what happens after transcription is less understood. In this issue of Molecular Microbiology, Jørgensen et al. (2012), Mika et al. (2012) and Thomason et al. (2012) report on small RNAs (McaS, RprA and GcvB) that together with the RNA‐chaperone Hfq regulate the mRNAs of csgD and other biofilm genes, and illustrate the burgeoning concept that the 5′ region of bacterial mRNA serves as a hub for sRNA‐mediated signal integration at the post‐transcriptional level.
The ethylene response factor AtERF98 enhances tolerance to salt through the transcriptional activation of ascorbic acid synthesis in Arabidopsis
Authors: Zhang Zhijin , Wang Juan , Zhang Rongxue , Huang Rongfeng 
Published: March 2012

SummaryAscorbic acid (AsA) is an important antioxidant in plants, and its biosynthesis is finely regulated through developmental and environmental cues; however, the regulatory mechanism remains unclear. In this report, the knockout and knockdown mutants of Arabidopsis AtERF98 decreased the AsA level, whereas the overexpression of AtERF98 increased it, which suggests that AtERF98 plays an important role in regulating AsA biosynthesis. AtERF98‐overexpressing plants showed enhanced expression of AsA synthesis genes in the d‐mannose/l‐galactose (d‐Man/l‐Gal) pathway and the myo‐inositol pathway gene MIOX4, as well as of AsA turnover genes. In contrast, AtERF98 mutants showed decreased expression of AsA synthesis genes in the d‐Man/l‐Gal pathway but not of the myo‐inositol pathway gene or AsA turnover genes. In addition, the role of AtERF98 in regulating AsA production was significantly impaired in the d‐Man/l‐Gal pathway mutant vtc1‐1, but the expression of the myo‐inositol pathway gene or AsA turnover genes was not affected, which indicates that the regulation of AtERF98 in AsA synthesis is primarily mediated by the d‐Man/l‐Gal pathway. Transient expression and chromatin immunoprecipitation assays further showed that AtERF98 binds to the promoter of VTC1, which indicates that AtERF98 modulates AsA biosynthesis by directly regulating the expression of the AsA synthesis genes. Moreover, the knockout mutant aterf98‐1 displayed decreased salt‐induced AsA synthesis and reduced tolerance to salt. The supplementation of exogenous AsA increased the salt tolerance of aterf98‐1; coincidently, the enhanced salt tolerance of AtERF98‐overexpressing plants was impaired in vtc1‐1. Thus, our data provide evidence that the regulation of AtERF98 in AsA biosynthesis contributes to enhanced salt tolerance in Arabidopsis.
Brain Base Arteries: Pattern and Variation in the European Otter (Lutra Lutra)
Authors: Brudnicki W. 
Published: March 2012

SummaryThe pattern and variation of the brain base arteries were investigated in 30 specimens of European otter. It was found that the vascular pattern in this species is similar to the vascular pattern found in other Carnivora. A very well‐developed basilar artery, which was formed as a result of the anastomosis of equally well‐developed vertebral arteries and the ventral spinal artery, was demonstrated to be characteristic of the species. Most of the variation in the pattern of origin concerned the origin of the middle cerebral arteries and labyrinthine arteries. In a single individual, a double middle cerebral artery was observed. Overall, the specimens demonstrated a clear regularity in the pattern of vessels in the base of the brain and a small range of variation.
Misinterpreting the potential benefits of aggregation for reducing desiccation in the intertidal: a simple analogy
Authors: Stafford Richard , Davies Mark S. , Williams Gray A. 
Published: March 2012

AbstractThe potential adaptive benefits of aggregation in intertidal invertebrates, in terms of preventing desiccation stress, are logical, but have proved difficult to confirm from field measurements. Through a simple analogy we explain why this may be so, especially for those species that do not solely forage when fully immersed. Measuring water content (or osmotic potentials of body fluids) of individuals that become inactive in aggregations and comparing this with non‐aggregated individuals, which is the most common method of determining adaptive benefits of aggregation to desiccation, (i) causes any relationships between desiccation and aggregation to be, at best, weakly related due to variability in the different times that individuals enter aggregations, and (ii) is not measuring the true benefit of aggregation, which in this case should be measured as a reduction in the rate of water loss. Further, the design of field studies or experiments to determine the benefits of aggregation in terms of desiccation reduction is extremely challenging, due to the unavoidable repeated disturbances to individuals that are necessary to measure water levels at multiple occasions, in order to measure the rate of water loss. We suggest that development of biomimetic sensors, such as modification of the robolimpet sensor, are required to measure in situ rates of water loss with a high temporal resolution. Although such sensors may not be truly physiologically realistic, they are likely to provide the least confounded approach to understanding benefits of aggregation in terms of physical stress reduction.
Antioxidant Mechanisms and their Benefit on Post‐thaw Boar Sperm Quality
Authors: Bathgate R 
Published: March 2012

ContentsWhile being an important component of normal cellular function, excess levels of reactive oxygen species (ROS) cause cell damage and death. The ability to protect sperm against oxidative damage is of particular importance in the artificial reproduction industry because of the increased production of ROS by the sperm cell during processing. This review discusses the formation of ROS and the use of antioxidants in protecting boar sperm against oxidative damage.
Biological Markers of Boar Fertility
Authors: Dyck MK , Foxcroft GR , Novak S , Ruiz‐Sanchez A , Patterson J , Dixon WT 
Published: March 2012

ContentsThe semen evaluation techniques used in most commercial artificial insemination centers, which includes sperm motility and morphology measurements, provides a very conservative estimate of the relative fertility of individual boars. As well, differences in relative boar fertility are masked by the widespread use of pooled semen for commercial artificial insemination (AI) in many countries. Furthermore, the relatively high sperm numbers used in commercial AI practice usually compensate for reduced fertility, as can be seen in some boars when lower numbers of sperm are used for AI. The increased efficiency of pork production should involve enhanced use of boars with strong reproductive efficiency and the highest genetic merit for important production traits. Given that the current measures of semen quality are not always indicative of fertility and reproductive performance in boars, accurate and predictive genetic and protein markers are still needed. Recently, significant efforts have been made to identify reliable markers that allow for the identification and exclusion of sires with reduced reproductive efficiency. This paper reviews the current status of proteomic and genomic markers of fertility in boars in relation to other livestock species.
International Conference on Boar Semen Preservation (ICBSP): The First 25 Years
Authors: Johnson LA 
Published: March 2012

ContentsThe International Conference on Boar Semen Preservation (ICBSP) has been in existence for 25 years. During that time, six conferences have been held in Europe and North America. Each conference has sought to communicate research advances in pig semen technology and artificial insemination (AI). Clearly, the conference has been a catalyst for the advancement of various improvements in semen preservation and AI. In addition, the conference has served to initiate collaboration among scientists worldwide. A summary of problems that remain to be investigated and solved in swine semen technology is provided.
Mechanisms of Sperm Storage in the Female Reproductive Tract: an Interspecies Comparison
Authors: Holt William V. 
Published: March 2012

ContentsOnce semen has been collected for artificial insemination, it is diluted into extenders designed to prevent its deterioration over the period prior to insemination. If the semen is not frozen, the extenders provide protection for a period of a few hours to a few days, depending on species. Despite the efforts of biotechnologists to increase the duration of storage without compromising fertility, there has been relatively little progress for many years. However, comparative studies in diverse species have revealed that long‐term sperm storage (up to months and years) within the female reproductive tract is relatively commonplace in reptiles, fishes, birds and amphibians. Even among mammals, some species of bat have evolved mechanisms for storing spermatozoa for several months in the uterus or oviduct so that they can mate in the autumn but postpone fertilization until the spring. We currently know little about the mechanisms that support such long‐term sperm storage, mainly because evidence from such species is either absent or fragmentary. Nevertheless, parallels between mammalian and other systems, where spermatozoa are sequestered in sperm storage tubules, suggest that the enclosure of spermatozoa within pockets of epithelial cells may be sufficient to achieve long‐term sperm storage. In addition, recent evidence from sperm‐storing bats has suggested an alternative, or additional, hypothesis that the modulation of apoptosis within epithelial cells is important in controlling sperm survival. Despite a lack of direct experimental evidence from a wide variety of species, I propose that there is now enough evidence to warrant investigation of these hypotheses.
Stress and Dietary Factors Modify Boar Sperm for Processing
Authors: Radomil L , Pettitt MJ , Merkies KM , Hickey KD , Buhr MM 
Published: March 2012

ContentsThis paper reviews stresses boar sperm undergo during processing and presents preliminary results of dietary modification that minimize this damage. Processing for artificial insemination (AI) stresses boar sperm by osmotic effects; altering cell size, shape and membranes; intracellular ice formation; and production of reactive oxygen species (ROS). Sperm response to ROS is concentration‐dependent, with low levels activating the ERK pathway to stimulate tyrosine phosphorylation (Tyr‐P) and capacitation, but high concentrations or inappropriately timed onset of ROS pathways can harm sperm. Fresh boar sperm exposed to ROS increased intracellular hydrogen peroxide (H2O2) phospholipase and lipid peroxidation, maintained viability but lost motility and underwent acrosome reactions (AR). Direct incorporation of lipids ± the antioxidant Vitamin E improves the survival of liquid‐ and frozen‐stored semen. Boars fed dietary flaxseed for 8 weeks to increase n‐3 fatty acids displayed improved sperm morphology (p < 0.05), increased membrane fluidity (p < 0.05) and better retention of motility and viability during 5–7 day storage (p < 0.05). Processes reducing oxidative damage to stored sperm should be evaluated.
Do CASA Systems Satisfy Consumers Demands? A Critical Analysis
Authors: Feitsma H , Broekhuijse MLWJ , Gadella BM 
Published: March 2012

ContentsBoar studs are often offered new technologies including several CASA (computer‐assisted semen analysis) systems. However, independent information to assist their purchase decisions is not available. The systems accuracy and repeatability variation because of different factors can be evaluated through duplicate testing of semen samples and comparison of the results according to WHO standards for humans. This primary analysis and a thorough economic cost benefit evaluation will help to decide whether the purchase of a CASA system will be profitable for a boar stud. Our experience of implementing several CASA systems in the cooperative Dutch Artificial Insemination (AI) centres is used as a base for this discussion.