Deep supercooling enabled by surface impregnation with lipophilic substances explains the survival of overwintering buds at extreme freezing

The frost survival mechanism of vegetative buds of angiosperms was suggested to be extracellular freezing causing dehydration, elevated osmotic potential to prevent freezing. However, extreme dehydration would be needed to avoid freezing at the temperatures down to ?45°C encountered by many trees. Buds of Alnus alnobetula, in common with other frost hardy angiosperms, excrete a lipophilic substance, whose functional role remains unclear. Freezing of buds was studied by infrared thermography, psychrometry, and cryomicroscopy. Buds of A. alnobetula did not survive by extracellular ice tolerance but by deep supercooling, down to ?45°C. An internal ice barrier prevented ice penetration from the frozen stem into the bud. Cryomicroscopy revealed a new freezing mechanism. Until now, supercooled buds lost water towards ice masses that form in the subtending stem and/or bud scales. In A. alnobetula, ice forms harmlessly inside the bud between the supercooled leaves. This would immediately trigger intracellular freezing and kill the supercooled bud in other species. In A. alnobetula, lipophilic substances (triterpenoids and flavonoid aglycones) impregnate the surface of bud leaves. These prevent extrinsic ice nucleation so allowing supercooling. This suggests a means to protect forestry and agricultural crops from extrinsic ice nucleation allowing transient supercooling during night frosts.     

Negative autoregulation by FAS mediates robust fetal erythropoiesis

Tissue development is regulated by signaling networks that control developmental rate and determine ultimate tissue mass. Here we present a novel computational algorithm used to identify regulatory feedback and feedforward interactions between progenitors in developing erythroid tissue. The algorithm makes use of dynamic measurements of red cell progenitors between embryonic days 12 and 15 in the mouse. It selects for intercellular interactions that reproduce the erythroid developmental process and endow it with robustness to external perturbations. This analysis predicts that negative autoregulatory interactions arise between early erythroblasts of similar maturation stage. By studying embryos mutant for the death receptor FAS, or for its ligand, FASL, and by measuring the rate of FAS-mediated apoptosis in vivo, we show that FAS and FASL are pivotal negative regulators of fetal erythropoiesis, in the manner predicted by the computational model. We suggest that apoptosis in erythroid development mediates robust homeostasis regulating the number of red blood cells reaching maturity.     

Community Next Steps for Making Globally Unique Identifiers Work for Biocollections Data

Biodiversity data is being digitized and made available online at a rapidly increasing rate but current practices typically do not preserve linkages between these data, which impedes interoperation, provenance tracking, and assembly of larger datasets. For data associated with biocollections, the biodiversity community has long recognized that an essential part of establishing and preserving linkages is to apply globally unique identifiers at the point when data are generated in the field and to persist these identifiers downstream, but this is seldom implemented in practice. There has neither been coalescence towards one single identifier solution (as in some other domains), nor even a set of recommended best practices and standards to support multiple identifier schemes sharing consistent responses. In order to further progress towards a broader community consensus, a group of biocollections and informatics experts assembled in Stockholm in October 2014 to discuss community next steps to overcome current roadblocks. The workshop participants divided into four groups focusing on: identifier practice in current field biocollections; identifier application for legacy biocollections; identifiers as applied to biodiversity data records as they are published and made available in semantically marked-up publications; and cross-cutting identifier solutions that bridge across these domains. The main outcome was consensus on key issues, including recognition of differences between legacy and new biocollections processes, the need for identifier metadata profiles that can report information on identifier persistence missions, and the unambiguous indication of the type of object associated with the identifier. Current identifier characteristics are also summarized, and an overview of available schemes and practices is provided.     

Association between oral health, cognitive impairment and oral health-related quality of life

doi: 10.1111/j.1741‐2358.2011.00542.x
Association between oral health, cognitive impairment and oral health–related quality of life Objective: Investigating oral health–related quality of life’s (OH‐QoL) relationship with cognitive state. Background: Oral health affects OH‐QoL and is poor in institutionalised and cognitively impaired people. Material and Methods: This was a cross‐sectional study involving 215 institutionalised elderly (82.9 mean age), who were interviewed, examined and cognitively screened using the Pfeiffer test. Results: Mean GOHAI score was 53.1; only 43.7% of the participants reported having a good OH‐QoL. Needing help with dressing or washing (OR 2.14; p = 0.004), having one to nine teeth (OR 4.65; p ≥ 0.001), eight or less occluding pairs (OR 2.74; p = 0.002), one to three caries (OR 1.85; p = 0.005) and being cognitive impaired (OR 0.54; p = 0.034) were significantly associated with altered OH‐QoL in bi‐variate analysis. Being edentulous (OR 3.18; p = 0.0046), having 1–9 teeth (OR 2.62; p = 0.056) and presenting mild cognitive impairment (MCI) (OR 0.32; p = 0.016) appeared as predictive variables in logistic regression for having an altered OH‐QoL. Conclusions: Participants having MCI had significantly better GOHAI score than cognitively normal residents. Performing cognitive screening parallel to applying any OH‐QoL instrument would make the results more reliable and would benefit cognitively impaired people.     

Meiosis in autologous ectopic transplants of immature testicular tissue grafted to Callithrix jacchus

Grafting of immature testicular tissue provides a tool to examine testicular development and may offer a perspective for preservation of fertility in prepubertal patients. Successful xenografting in mice, resulting in mature spermatids, has been performed in several species but has failed with testicular tissues from the common marmoset, Callithrix jacchus. Previous data indicate that the hormonal milieu provided by the mouse host might cause this failure. We conducted autologous ectopic transplantation of testicular fragments under the back skin in newborn marmoset monkeys. Seventeen months after transplantation, we found viable transplants in 2 out of the 4 grafted animals. In the transplants, tubules developed up to a state intermediate between the pregraft situation and adult controls. Dividing spermatogonia and primary spermatocytes were present. Boule-like positivity and CDC25A negativity indicated that spermatogenesis was arrested at early meiosis. Immunohistochemistry revealed normal maturation of Sertoli cells, Leydig cells, and peritubular cells. Serum testosterone values were not restored to the normal range and bioactive chorionic gonadotropin levels increased to castrate levels. Meiotic arrest could have occurred in the grafts because of lack of sufficient testosterone or because of hyperthermia caused by the ectopic position of the grafts. We conclude that autologous transplants of immature testicular tissues in the marmoset can mature up to meiosis but that normal serum testosterone levels are not restored. Further studies have to be performed to overcome the meiotic arrest to explore the model further and to develop therapeutic options.     

Native and invasive vegetation of karst springs in Wisconsin’s Driftless area

Little is known about the vegetation found in the karst springs of Wisconsin’s unglaciated region, the Driftless Area. We sampled 26 of these springs, documenting all associated plant species and their status (native, non-native, invasive) and analyzed whether vegetation patterns are related to spring orientation or to spring area. Two-way ANOVA results show that non-native and invasive species, namely Nasturtium officinale (watercress, Brassicaceae), are significantly more abundant than natives in north-facing springs (p < 0.01), but not in south-facing springs. Generally, native species are restricted to, or more abundant in, south-facing springs, and may have a microtopographical preference for these sites, which may receive more direct solar radiation. Nasturtium officinale, the most abundant invasive species, has high cover values in both north and south orientations and is less restricted in its distribution. Correlation analysis shows that the larger the spring, the higher the percent of Nasturtium (p < 0.01) and invasive species cover (as a percent of spring area) (p < 0.005). Larger springs often had slower moving water and this may have contributed to the success of Nasturtium, which may outcompete shade-intolerant natives in the larger springs. Native species cover was negatively related to spring area, though this result was marginally insignificant (p = 0.08).     

Habitats, abundance patterns and isotopic signals of morphotypes of the planktonic foraminifer Globigerinoides ruber (d'Orbigny) in the eastern Mediterranean Sea since the Marine Isotopic Stage 12

The chemical composition of shells of the planktonic foraminifer Globigerinoides ruber (white) is frequently used to determine past sea surface conditions. Recently, it has been shown that arbitrarily defined morphotypes within this species exhibit different chemical and isotopic signatures. Here, we investigate the occurrence through time and in space of morphological types of G. ruber (white) in late Quaternary and Holocene sediments of the central and the eastern Mediterranean Sea. In 115 samples representing two distinct time intervals (MIS 1–2 and MIS 9–12) at ODP Site 964 and the piston core GeoTü-SL96, we have defined three morphological types within this species and determined their relative abundances and stable isotopic composition. A quantitative analysis of morphological variation within G. ruber (white) in four samples revealed that the subjectively defined morphotypes occupy separate segments of a continuous and homogenous morphospace. We further show that the abundance of the morphotypes changes significantly between glacials and interglacials and that the three morphotypes of G. ruber show significant offsets in their stable isotopic composition. These offsets are consistent within glacial and interglacial stages but their sign is systematically reversed between the two Sites. Since the isotopic shifts among the three G. ruber morphotypes are systematic and often exceed 1‰, their understanding is essential for the interpretation of all G. ruber-based proxy records for the paleoceanographic development of the Mediterranean during the late Quaternary.     

Discovery of a novel class of 2-mercaptohexanoic acid derivatives as highly active PPARα agonists

A novel and robust scaffold for highly active PPARα agonists based on the 2-mercaptohexanoic acid substructure is presented. Systematic structural variation of the substitution pattern of the phenolic backbone yielded detailed SAR especially of ortho and meta substituents. We corroborated the importance of the sulfur atom as well as of the n-butyl chain for PPARα activity in the 2-mercaptohexanoic acid head group by preparation of carbon analogs and α-unsubstituted derivatives. Compound 10 represents a low nano molar active PPARα activator with excellent selectivity towards PPARγ.     

First evidence for adoption in California sea lions

Demographic parameters such as birth and death rates determine the persistence of populations. Understanding the mechanisms that influence these rates is essential to developing effective management strategies. Alloparental behavior, or the care of non-filial young, has been documented in many species and has been shown to influence offspring survival. However, the role of alloparental behavior in maintaining population viability has not been previously studied. Here, we provide the first evidence for adoption in California sea lions and show that adoption potentially works to maintain a high survival rate of young and may ultimately contribute to population persistence. Alloparental behavior should have a positive effect on the population growth rate when the sum of the effects on fitness for the alloparent and beneficiary is positive.