The golf ball method for rapid assessment of grassland structure

A key task for native grassland managers is to assess when biomass reduction is necessary to maintain plant and animal diversity. This requires managers to monitor grassland structure. Parks Victoria and La Trobe University developed a method for rapid assessment of grassland structure using golf balls. Baker‐Gabb et al. (Ecological Management & Restoration, 17, 2016, p235) provide an example of where the method has been used to manage grassland structure to favour an endangered bird, the Plains‐wanderer (Pedionomus torquatus). In this study, we provide further critical analysis of the method using three data sets collected across different parts of Victoria that relate golf ball scores to various habitat attributes. We demonstrate how the golf ball score provides a good surrogate for key aspects of grassland structure. We show that the method does not provide a reliable surrogate for above‐ground biomass or vegetation cover, although we discuss how biomass and cover are not particularly good indicators of grassland structure. We argue that elements of grassland structure may be better correlated with desired conservation outcomes (e.g. plant species diversity or the presence of a particular species) than biomass or cover alone. We discuss examples of how the golf ball method has been used, and how it can be improved. The method will be particularly useful where a link can be demonstrated between golf ball scores and desired conservation outcomes, such as in the case of the Plains‐wanderer.     

A new method for surface staining large slices of fixed brain using a copper phthalocyanine dye

Here we describe a method for gross staining of gray matter in slices of formaldehyde-fixed human brain. After protection of white matter with 4% phenol at 60°C for 5 min followed by a cold water wash, the gray matter was stained for 10-15 min at 20-25°C with 1% aqueous copper(II) phthalocyanine tetrasulfonic acid tetrasodium salt (CPTS). The staining resisted all attempts to be washed from the gray matter. Stained slices can be stored indefinitely in slightly acidified water, or plastinated as permanent dry specimens.     

Inducible nitric oxide synthase and Salmonella infection

Salmonella infection is associated with the increased expression of inducible nitric oxide synthase in macrophages and other cells. This review summarizes current knowledge of the molecular mechanisms involved in the induction process, and discusses the functional significance of nitric oxide production in the context of host defense against Salmonella.     

Spontaneous coronary artery dissection: long stenting in a patient with polycythemia vera

Spontaneous coronary artery dissection is a rare cause of myocardial ischemia or sudden cardiac death. We describe a patient with polycythemia vera and a chronic spontaneous coronary artery dissection who was treated with successful angioplasty and long stenting.     

Thwarting of behaviour in different contexts and the gakel-call in the laying hen

Earlier studies have shown that thwarting of feeding behaviour in the laying hen is expressed through a specific vocalisation, the gakel-call. The first aim of this study was to investigate whether the effect of deprivation per se on the occurrence of gakel-calls can be distinguished from the effect of the additional frustration. Frustration is defined as the state of an animal that results from nonreward in the expectancy of reward. The second aim was to investigate whether the occurrence of gakel-calls is restricted to a food context or whether it can be regarded as an expression of frustration in general. For this purpose, 20 hens were deprived of food, water and dustbath. After deprivation at a fixed time, a cue was given and the hens were rewarded with access to food, water or dust during a 15-min session on 4 consecutive days. On the fifth day, they were thwarted in the associated behaviours by blocking the access to these commodities, after the hens had been presented the signal that previously preceded the reward. We then recorded behaviours that might reflect the state of frustration in three 15-min periods. The period "Pre-Frustration" started 15 min before "Frustration". This, in turn, was followed by the period "Post-frustration" in which the hens were rewarded again. Nesting behaviour was thwarted by blocking the access to the nest (Frustration) after a hen had reached the last stage of its prelaying behaviour.In the food, water and dustbath context, deprivation elicited gakel-calls. The additional frustration resulted in a higher number of gakel-calls in all contexts except the food context. However, together with the findings of previous experiments, the results of this study suggest that frustration, in general, is expressed through the gakel-call. Frustration in the nest context elicited more gakel-calls than the other contexts. This latter finding is discussed in the light of the occurrence of the gakel-call under natural circumstances.     

A mRNA landscape of bovine embryos after standard and MAPK-inhibited culture conditions: a comparative analysis

Background

Genes and signalling pathways involved in pluripotency have been studied extensively in mouse and human pre-implantation embryos and embryonic stem (ES) cells. The unsuccessful attempts to generate ES cell lines from other species including cattle suggests that other genes and pathways are involved in maintaining pluripotency in these species. To investigate which genes are involved in bovine pluripotency, expression profiles were generated from morula, blastocyst, trophectoderm and inner cell mass (ICM) samples using microarray analysis. As MAPK inhibition can increase the NANOG/GATA6 ratio in the inner cell mass, additionally blastocysts were cultured in the presence of a MAPK inhibitor and changes in gene expression in the inner cell mass were analysed.

Results

Between morula and blastocyst 3,774 genes were differentially expressed and the largest differences were found in blastocyst up-regulated genes. Gene ontology (GO) analysis shows lipid metabolic process as the term most enriched with genes expressed at higher levels in blastocysts. Genes with higher expression levels in morulae were enriched in the RNA processing GO term. Of the 497 differentially expressed genes comparing ICM and TE, the expression of NANOG, SOX2 and POU5F1 was increased in the ICM confirming their evolutionary preserved role in pluripotency. Several genes implicated to be involved in differentiation or fate determination were also expressed at higher levels in the ICM. Genes expressed at higher levels in the ICM were enriched in the RNA splicing and regulation of gene expression GO term. Although NANOG expression was elevated upon MAPK inhibition, SOX2 and POU5F1 expression showed little increase. Expression of other genes in the MAPK pathway including DUSP4 and SPRY4, or influenced by MAPK inhibition such as IFNT, was down-regulated.

Conclusion

The data obtained from the microarray studies provide further insight in gene expression during bovine embryonic development. They show an expression profile in pluripotent cells that indicates a pluripotent, epiblast-like state. The inability to culture ICM cells as stem cells in the presence of an inhibitor of MAPK activity together with the reported data indicates that MAPK inhibition alone is not sufficient to maintain a pluripotent character in bovine cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1448-x) contains supplementary material, which is available to authorized users.     

Adenine nucleotides decrease the apparent Km of endogenous natriuretic peptide receptors for GTP

Natriuretic peptide receptors A (NPR-A) and B (NPR-B) mediate most effects of natriuretic peptides by synthesizing cGMP. ATP increases the activity of these receptors by an unknown mechanism. We recently reported that a nonhydrolyzable form of ATP, adenylyl imidodiphosphate (AMPPNP), stabilizes but is not required for the activation of NPR-A and NPR-B in membranes from highly overexpressing cells. Here, we repeated these studies on receptors expressed in endogenous settings. Kinetic analysis indicated that both AMPPNP and ATP dramatically decrease the apparent K(m) of both receptors for GTP but had little effect on the V(max). The EC(50) for AMPPNP decreased as substrate concentration increased whereas the magnitude of the effect was greater at lower GTP concentrations. ATP increased the activity of a mutant receptor containing glutamates substituted for all known phosphorylation sites similarly to the wild-type receptor, consistent with a phosphorylation independent mechanism. Finally, the putative ATP binding sites were investigated. Mutation of the ATP modulatory domain region had no effect, but mutation of K535A dramatically diminished ANP-dependent cyclase activity in a manner that was unresponsive to ATP. Mutation of the highly conserved 630-KSS to AAA (all alanines) resulted in an expressed receptor that had no detectable guanylyl cyclase activity. We conclude that ATP is not required for the initial activation of NPRs but does increase activity over time by reducing the apparent K(m) for GTP.     

Tree rings provide no evidence of a CO2 fertilization effect in old‐growth subalpine forests of western Canada

Atmospheric CO₂ concentrations are now 1.7 times higher than the preindustrial values. Although photosynthetic rates are hypothesized to increase in response to rising atmospheric CO₂ concentrations, results from in situ experiments are inconsistent in supporting a CO₂ fertilization effect of tree growth. Tree‐ring data provide a historical record of tree‐level productivity that can be used to evaluate long‐term responses of tree growth. We use tree‐ring data from old‐growth, subalpine forests of western Canada that have not had a stand‐replacing disturbance for hundreds of years to determine if growth has increased over 19th and 20th centuries. Our sample consisted of 5,858 trees belonging to five species distributed over two sites in the coastal zone and two in the continental climate of the interior. We calculated annual increments in tree basal area, adjusted these increments for tree size and age, and tested whether there was a detectable temporal trend in tree growth over the 19th and 20th centuries. We found a similar pattern in 20th century growth trends among all species at all sites. Growth during the 19th century was mostly stable or increasing, with the exception of one of the coastal sites, where tree growth was slightly decreasing; whereas growth during the 20th century consistently decreased. The unexpected decrease in growth during the 20th century indicates that there was no CO₂ fertilization effect on photosynthesis. We compared the growth trends from our four sites to the trends simulated by seven Earth System Models, and saw that most of the models did not predict these growth declines. Overall, our results indicate that these old‐growth forests are unlikely to increase their carbon storage capacity in response to rising atmospheric CO₂, and thus are unlikely to contribute substantially to offsetting future carbon emissions.