Lesser double‐collared sunbirds Nectarinia chalybea do not compensate for hatching asynchrony by adjusting egg mass or yolk androgens

Substantial amounts of maternal androgens are found in birds’ eggs and have been shown to benefit offspring development. Within‐clutch patterns of increasing androgen concentrations over the laying sequence are often hypothesized to compensate for the negative effects of hatching asynchrony. However, detrimental effects to offspring fitness of exposure to high yolk androgen levels have also been demonstrated. This suggests that mothers should forego these costs to their offspring when the need for compensation for hatching asynchrony is low or when alternative compensatory strategies, e.g. in terms of increasing egg mass, are available. Here we show that in the south‐temperate lesser double‐collared sunbird Nectarinia chalybea, a species with hatching asynchrony but also with high survival of last‐hatched chicks, mothers do not deposit resources differentially in terms of either yolk androgen concentration or egg mass across the laying sequence. We discuss to what extend this challenges the original explanation of within‐clutch variation in these egg parameters and offer some explanation for their between‐clutch variation which was related to female body mass.     

Variations in the vulvar temperature of sows during proestrus and estrus as determined by infrared thermography and its relation to ovulation

The prediction of ovulation time is one of the most important and yet difficult processes in pig production, and it has a considerable impact on the fertility of the herd and litter size. The objective of this study was to assess the vulvar skin temperature of sows during proestrus and estrus using infrared thermography and to establish a possible relationship between the variations in vulvar temperature and ovulation. The experimental group comprised 36 crossbred Large White × Landrace females, of which 6 were gilts and 30 were multiparous sows. Estrus was detected twice daily and the temperature was obtained every 6 hours from the vulvar area and from two control points in the gluteal area (Gluteal skin temperature [GST]). A third variable, vulvar–gluteal temperature (VGT) was obtained from the difference between the vulvar skin temperature and the GST values. The animals were divided into two subgroups: group A consisting of 11 animals with estrus detected at 6:00 AM, Day 4 postweaning, and group B comprising seven animals with estrus detected at 6:00 AM, Day 5 post-weaning. Both groups showed a similar trend in the VGT. The VGT increased during the proestrus, reaching a peak 24 hours before estrus in group A and 48 hours before estrus in group B. The VGT then decreased markedly reaching the lowest value in groups A and B, respectively, 12 and 6 hours after estrus. Although the time of ovulation was only estimated on the basis of a literature review, the matching between the temporal variations of the VGT values and the predicted time of the peak of estradiol secretion that ultimately leads to the ovulation processes suggests that the VGT values represent a potential predictive marker of the ovulatory events.     

Aqua bridge cleavage and metal ion extrusion by thiocyanate anions in a dicopper complex

Reaction of the imidazolidinyl phenolate-based ligand, H₃L [(2-(2′-hydroxyphenyl)-1,3-bis[4-(2-hydroxyphenyl)-3-azabut-3-enyl]-1,3-imidazolidine)] with Cu(ClO₄)₂·6H₂O produces an aqua-bridged cationic reactant complex [Cu₂(μ-H₂O)(μ-L)][ClO₄]·1.5H₂O (1·1.5H₂O). Solution phase interaction of 1·1.5H₂O with SCN⁻ anions in 1:1 molar ratio leads to [Cu₂(μ-L)(NCS)]·2H₂O (2·2H₂O) that does not possess anymore the reactive aqua bridge but instead a terminal SCN⁻ anion coordinated only to one Cu^II ion. Whereas in 1:2 molar ratio, partial extrusion of the Cu^II ions takes place to generate in situ [Cu(NCS)₃(OH₂)]⁻ anions. These complex anions then quantitatively replace anions in 1·1.5H₂O via ‘anion metathesis’ and concurrently remove the aqua bridge by coordination of linear MeCN to one of the Cu^II ions to give [Cu₂(μ-L)(CH₃CN)][Cu(NCS)₃(OH₂)] (3). The literature unknown [Cu(NCS)₃(OH₂)]⁻ anion forms an intimate H-bonded assembly with the cationic part of 3 to yield a novel [Cu₃] isosceles triangle. The precursor complex is known as antiferromagnetic whereas in 2·2H₂O, the Cu^II (S = 1/2) ions in a dinuclear entity exhibit ferromagnetic interactions (J/k_B = +15.0 K and g = 2.22) to yield an S_T = 1 spin ground state in good agreement with the M versus H data below 8 K.     

Structural studies of the exopolysaccharide consisting of a nonasaccharide repeating unit isolated from Lactobacillus rhamnosus KL37B

A novel structure of exopolysaccharide from the lactic acid bacteria (LAB) Lactobacillus rhamnosus KL37B, from the human intestinal flora, is described. During the structural investigation of the exopolysaccharide it was found that the repeating unit is a nonasaccharide, which is the largest repeating unit found in LAB exopolysaccharides to date. The polysaccharide material was prepared by TCA extraction of a bacterial cell mass, purified by anion-exchange and gel permeation chromatography and characterized using chemical and enzymatic methods. On the basis of monosaccharide and methylation analysis and also 1D and 2D ¹H and ¹³C NMR spectroscopy the exopolysaccharide was shown to be composed of the following nonasaccharide repeating unit:The physicochemical cell surface study and adhesive properties indicated distinct surface properties of Lactobacillus rhamnosus strain KL37B with high adhesive abilities to Caco-2 cells, hydrophobicity and slime production, in comparison to other Lactobacillus strains used as controls.     

Ovarian Cancer Cell Line Panel (OCCP): Clinical Importance of In Vitro Morphological Subtypes

Epithelial ovarian cancer is a highly heterogeneous disease and remains the most lethal gynaecological malignancy in the Western world. Therapeutic approaches need to account for inter-patient and intra-tumoural heterogeneity and detailed characterization of in vitro models representing the different histological and molecular ovarian cancer subtypes is critical to enable reliable preclinical testing. There are approximately 100 publicly available ovarian cancer cell lines but their cellular and molecular characteristics are largely undescribed. We have characterized 39 ovarian cancer cell lines under uniform conditions for growth characteristics, mRNA/microRNA expression, exon sequencing, drug response for clinically-relevant therapeutics and collated all available information on the original clinical features and site of origin. We tested for statistical associations between the cellular and molecular features of the lines and clinical features. Of the 39 ovarian cancer cell lines, 14 were assigned as high-grade serous, four serous-type, one low-grade serous and 20 non-serous type. Three morphological subtypes: Epithelial (n = 21), Round (n = 7) and Spindle (n = 12) were identified that showed distinct biological and molecular characteristics, including overexpression of cell movement and migration-associated genes in the Spindle subtype. Comparison with the original clinical data showed association of the spindle-like tumours with metastasis, advanced stage, suboptimal debulking and poor prognosis. In addition, the expression profiles of Spindle, Round and Epithelial morphologies clustered with the previously described C1-stromal, C5-mesenchymal and C4 ovarian subtype expression profiles respectively. Comprehensive profiling of 39 ovarian cancer cell lines under controlled, uniform conditions demonstrates clinically relevant cellular and genomic characteristics. This data provides a rational basis for selecting models to develop specific treatment approaches for histological and molecular subtypes of ovarian cancer.     

Characterization of Glycosaminoglycan (GAG) Sulfatases from the Human Gut Symbiont Bacteroides thetaiotaomicron Reveals the First GAG-specific Bacterial Endosulfatase

Despite the importance of the microbiota in human physiology, the molecular bases that govern the interactions between these commensal bacteria and their host remain poorly understood. We recently reported that sulfatases play a key role in the adaptation of a major human commensal bacterium, Bacteroides thetaiotaomicron, to its host (Benjdia, A., Martens, E. C., Gordon, J. I., and Berteau, O. (2011) J. Biol. Chem. 286, 25973–25982). We hypothesized that sulfatases are instrumental for this bacterium, and related Bacteroides species, to metabolize highly sulfated glycans (i.e. mucins and glycosaminoglycans (GAGs)) and to colonize the intestinal mucosal layer. Based on our previous study, we investigated 10 sulfatase genes induced in the presence of host glycans. Biochemical characterization of these potential sulfatases allowed the identification of GAG-specific sulfatases selective for the type of saccharide residue and the attachment position of the sulfate group. Although some GAG-specific bacterial sulfatase activities have been described in the literature, we report here for the first time the identity and the biochemical characterization of four GAG-specific sulfatases. Furthermore, contrary to the current paradigm, we discovered that B. thetaiotaomicron possesses an authentic GAG endosulfatase that is active at the polymer level. This type of sulfatase is the first one to be identified in a bacterium. Our study thus demonstrates that bacteria have evolved more sophisticated and diverse GAG sulfatases than anticipated and establishes how B. thetaiotaomicron, and other major human commensal bacteria, can metabolize and potentially tailor complex host glycans.     

Characterisation of Antarctic cyanobacteria and comparison with New Zealand strains

Cyanobacterial mats are common in Antarctic lakes, ponds and on moist soils. The species comprising these mats have adapted to tolerate extreme conditions (e.g. high salinities and UV radiation, freezing and extended periods of darkness). In this study, cyanobacterial mats were collected from shallow melt-water ponds in Pyramid Trough in Southern Victoria Land, Antarctica. Eight strains were isolated and characterised by morphological and molecular (16S rRNA gene sequences) techniques and their fatty acid methyl ester (FAME) and lipid class profiles determined. These data were compared to parallel information obtained from cyanobacterial cultures isolated from New Zealand. In general, the morphological and molecular characterisation complemented each other, and the Antarctic strains identified belonged to the orders: Oscillatoriales (six), Nostocales (one) and Chroococcales (one). Two of the Antarctic strains (CYN67 and CYN68) showed low similarity (<96% 16S rRNA gene sequence) when compared to other cultured cyanobacteria. The fatty acid (FA) profiles from the Antarctic and New Zealand strains shared many similarities with palmitic (C16:0), stearic (C18:0) and oleic acid (C18:1n-9) most abundant. In contrast, the lipid class analysis differed among geographic locations with Antarctic strains containing higher amounts of hydrocarbons and eicosapentaenoic and hexadecatrienoic acids.