Nitrogen fertilizer replacement indexes of legume cover crops in the derived savanna of West Africa

Legume cover crops are a potential means for overcoming N depletion in the derived savanna of West Africa. A 3-year trial was, therefore, conducted near Ibadan, southwestern Nigeria to measure the N contribution of 13 legume cover crops as compared to urea –N, using a N fertilizer replacement index for a maize test crop. Two series of trials involved the following legume cover crop species: Aeschynomene histrix, Centrosema brasilianum, Centrosema pascuorum, Chamaecrista rotundifolia, Cajanus cajan, Crotalaria verrucosa, Crotalaria ochroleuca, Lablab purpureus, Mucuna pruriens, Psophocarpus palustris, Pseudovigna argentea, Pueraria phaseoloides and Stylosanthes hamata. Trials were undertaken using a complete block design. Cover crops were planted in 1994 (Series 1) and 1995 (Series 2) in separate sites and each series was subsequently slashed and planted for one season with maize (Zea mays) in 1995 and 1996. At the 50% flowering stage, N concentration of above-ground vegetation of cover crops ranged from 21 to 38 g N kg^–1. Nitrogen accumulated by 4.5-month old cover crops ranged from 14 to 240 kg N ha^–1, depending on species and year. Cover crops increased grain yield of the subsequent maize crop by 25–136% over the control without N application. Nitrogen uptake by the maize crop was higher following cover crops than after maize or natural grass. The N fertilizer replacement index of cover crops for maize ranged from 11 (A. histrix) to 96 kg N ha^–1 (C. cajan) in Series 2. Perennial (C. brasilianum, S. hamata, C. cajan, P. phaseoloides and C. verrucosa) and annual (C. rotundifolia, M. pruriens, C. ochroleuca and L. purpureus) species could potentially save 50 to 100 kg N ha^–1 for maize crops. The cover crops accumulated more N in the wetter than in the drier year. However, the N fertilizer replacement index was higher for subsequent maize grown in the drier year. The cover crop-N recovery in maize was also higher than the urea-N uptake in the drier year. The N fertilizer replacement indexes can be predicted using the above-ground biomass amount of cover crops at 20 weeks after planting (drier year) or the N concentration at that stage (wetter year).     

Diversity and distribution of saprobic microfungi in leaf litter of an Australian tropical rainforest

The diversity and distribution of microfungal assemblages in leaf litter of a tropical Australian forest was assessed using two methods: (1) cultures were isolated using a particle filtration protocol (wet season 2001), and (2) fruit bodies were observed directly on leaf surfaces following incubation in humid chambers (wet and dry season of 2002). Four tree species were studied using both methods, namely Cryptocarya mackinnoniana (Lauraceae), Elaeocarpus angustifolius (Elaeocarpaceae), Ficus pleurocarpa (Moraceae), and Opisthiolepis heterophylla (Proteaceae). An additional two species, Darlingia ferruginea (Proteaceae) and Ficus destruens (Moraceae), were studied using direct observations. In total, fruiting bodies of 185 microfungal species were recorded on leaf surfaces (31–81 species per tree species), and 419 morphotypes were detected among isolates obtained by particle filtration (111–203 morphotypes per tree species). Although the observed microfungal diversity was higher with the particle filtration protocol, both methods concurred with respect to microfungal distributions. The overlap of microfungal species in pair wise comparisons of tree species was low (14–30 %), and only 2 and 3 % of microfungal species were observed in leaves of all tree species by particle filtration and by direct observations respectively. Multivariate analysis of data from direct observations confirmed the hypothesis that microfungal assemblages are strongly influenced by host phylogeny and are also affected by seasonal and site factors. The importance of host species in shaping microfungal distributions was also supported by the particle filtration data. Several taxa new to science, as well as some widespread saprotrophs, were detected on only one host. The underlying reasons for this affinity remain unclear, but we hypothesise that a number of factors may be involved such as fungal adaptation to plant secondary metabolites or the presence of a biotrophic phase in the fungus' life cycle.     

Young Children’s Sensitivity to Their Own Ignorance in Informing Others

Prior research suggests that young children selectively inform others depending on others’ knowledge states. Yet, little is known whether children selectively inform others depending on their own knowledge states. To explore this issue, we manipulated 3- to 4-year-old children’s knowledge about the content of a box and assessed the impact on their decisions to inform another person. Moreover, we assessed the presence of uncertainty gestures while they inform another person in light of the suggestions that children''s gestures reflect early developing, perhaps transient, epistemic sensitivity. Finally, we compared children’s performance in the informing context to their explicit verbal judgment of their knowledge states to further confirm the existence of a performance gap between the two tasks. In their decisions to inform, children tend to accurately assess their ignorance, whereas they tend to overestimate their own knowledge states when asked to explicitly report them. Moreover, children display different levels of uncertainty gestures depending on the varying degrees of their informational access. These findings suggest that children’s implicit awareness of their own ignorance may be facilitated in a social, communicative context.     

Methods for mycelial breakage and isolation of mitochondria and vacuoles of Neurospora

A new and inexpensive glass-bead blender allows rapid, easy, and controlled cell breakage of Neurospora, with good organellar survival. The yield of mitochondria and vacuoles is comparable to or better than methods involving sand grinding or snail-gut digestion of cell walls. A method for removing cell wall fragments from a crude homogenate is described. Isolation of mitochondria and vacuoles from the crude homogenate with little cross-contamination is accomplished by density-gradient centrifugation in a fixed-angle rotor (Sorvall).     

A model of the control of cellular regeneration in the intestinal crypt after perturbation based solely on local stem cell regulation

Abstract. The control mechanisms involved in regeneration of murine intestinal crypts after perturbations are presently not well understood. The existence of some feedback signals from the cells on the villus to the cells in the crypt has been suggested. However, some recent experimental data point to the fact that regeneration in the crypt starts very early after perturbation, at a time when the villus cell population has hardly changed. In particular, this early cell proliferative activity is seen specifically at the bottom of the crypt, i.e. in the presumed stem cell zone and furthest from the villus.
The objective of this study was to investigate whether a new concept of regulation operating solely at the stem cell level could explain the present mass of accumulated data on the post-irradiation recovery, which is an extensively studied perturbation from the experimental point of view. In order to check its validity, the new concept was formalized as a mathematical simulation model thus enabling comparison with experimental data. The model describes the cellular development from stem cells to the mature villus cells. As a basic feature it is assumed that the self-maintenance and the cell cycle activity of the stem cells are controlled by the number of these cells in an autoregulatory fashion. The essential features of the experimental data (i.e. the recovery with time and the consistency between different types of measurements) can be very well reproduced by simulations using a range of model parameters. Thus, we conclude that stem cell autoregulation is a valid concept which could replace the villus crypt feedback concept in explaining the early changes after irradiation when the damage primarily affects the crypt. The question of the detailed nature of the control process requires further investigation.     

Phylogenetic evidence for the transfer of Eubacterium suis to the genus Actinomyces as Actinomyces suis comb. nov.

The 16S rRNA primary structures of Eubacterium suis DSM 20639T (T = type strain) and Bifidobacterium bifidum DSM 20456T were determined by sequencing in vitro amplified rDNA. Sequence comparisons indicated that B. bifidum is moderately related to representatives of the genera Actinomyces and Mobiluncus. The closest relative of E. suis is Actinomyces pyogenes. E. suis and A. pyogenes are more closely related phylogenetically to one another than to the other Actinomyces species that have been investigated by using comparative 16S rRNA analysis. Therefore, we propose that E. suis should be transferred to the genus Actinomyces as Actinomyces suis comb. nov.     

N-aryl-piperidine-4-carboxamides as a novel class of potent inhibitors of MALT1 proteolytic activity

Starting from a weak screening hit, potent and selective inhibitors of the MALT1 protease function were elaborated. Advanced compounds displayed high potency in biochemical and cellular assays. Compounds showed activity in a mechanistic Jurkat T cell activation assay as well as in the B-cell lymphoma line OCI-Ly3, which suggests potential use of MALT1 inhibitors in the treatment of autoimmune diseases as well as B-cell lymphomas with a dysregulated NF-κB pathway. Initially, rat pharmacokinetic properties of this compound series were dominated by very high clearance which could be linked to amide cleavage. Using a rat hepatocyte assay a good in vitro-in vivo correlation could be established which led to the identification of compounds with improved PK properties.     

Environmental determinants of genetic diversity in Caragana microphylla (Fabaceae) in northern China

Non‐rewarding orchids rely on various ruses to attract their pollinators. One of the most common is for them to resemble flowers sought by insects as food sources. This can range from generalized food deception to the mimicry of specific sympatric food plants. We investigated the basis of pollinator deception in the European food‐deceptive orchid Traunsteinera globosa, which has unusually compact flowerheads resembling those of sympatric rewarding species of Knautia and Scabiosa (Dipsacaceae), and Valeriana (Caprifoliaceae). Visual signals of T. globosa are similar in both fly and bee vision models to those of the sympatric food plants used in the choice experiments, but scent signals are divergent. Field experiments conducted in Austria and the Czech Republic showed that both naive and experienced (with respect to visitation of T. globosa) insect species approached the orchids at the same rate as food plants, but direct contact with orchid flowers was taxon specific. Flies were most easily duped into probing the orchid, and, in doing so, frequently received and deposited pollinaria, whereas most bees and butterflies avoided landing on orchid flowers. We conclude that T. globosa is a mimic of a guild of fly‐pollinated plants, but the ecological dependence of the orchid on its models remains to be fully tested. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2016, 180 , 269–294.     

Genome-Wide Identification of Epigenetic Hotspots Potentially Related to Cardiovascular Risk in Adult Women after a Complicated Pregnancy

Background

The physiological demands of pregnancy on the maternal cardiovascular system can catapult women into a metabolic syndrome that predisposes to atherosclerosis in later life. We sought to identify the nature of the epigenomic changes associated with the increased cardiovascular disease (CVD) risk in adult women following pre-eclampsia.

Findings

We assessed the genome wide epigenetic profile by methyl-C sequencing of monozygotic parous twin sister pairs discordant for a severe variant of pre-eclampsia. In the adult twin sisters at risk for CVD as a consequence of a complicated pregnancy, a set of 12 differentially methylated regions with at least 50% difference in methylation percentage and the same directional change was found to be shared between the affected twin sisters and significantly different compared to their unaffected monozygous sisters.

Conclusion

The current epigenetic marker set will permit targeted analysis of differentially methylated regions potentially related to CVD risk in large cohorts of adult women following complicated pregnancies.