Developmental defects of female-sterile mutants of Drosophila melanogaster

Gans et al. (1975) isolated female-sterile mutants, viable and normal in the homozygous state, producing apparently normal eggs which were unable to develop or developed into defective embryos or adults, even when fertilized with wild-type sperm. Developmental abnormalities of these mutants were surveyed by observing living and fixed material. The following types of mutants were distinguished according to the predominant developmental defect: (i) Eggs not developing at all, mostly remaining unfertilized. (ii) Eggs stopping development after a few cleavages, some with polyploid nuclei. (iii) Eggs stopping development at various embryonic stages, with haploid nuclei. (iv) Eggs with abnormal blastoderm, not developing further or giving abnormal embryos. (v) Eggs with abnormal gastrula, in one case with excessive invaginations, in another case with germ band failing to elongate. (vi) Eggs with embryos dying at different stages, without easily visible effects. Several of the mutants were temperature sensitive. In all the mutants there were eggs that died without developing. Most of the developmental defects appear to be due to general metabolic disturbances of the egg, not directly related to morphogenesis. There were no mutants affecting determination of a particular adult organ. The closest to a morphological type of mutation were those with abnormal blastoderm having successive bands of nuclei of different sizes. Those mutants were thermosensitive; at permissive termperatures they developed into agametic adults or adults with various defects of abdomens, wings or eyes. The nature of maternal genetic control of early morphogensis was discussed.     

Chondrocalcin is internalized by chondrocytes and triggers cartilage destruction via an interleukin-1β-dependent pathway

Chondrocalcin is among the most highly synthesized polypeptides in cartilage. This protein is released from its parent molecule, type II pro-collagen, after secretion by chondrocytes. A participation of extracellular, isolated chondrocalcin in mineralization was proposed more than 25 years ago, but never demonstrated. Here, exogenous chondrocalcin was found to trigger MMP13 secretion and cartilage destruction ex vivo in human cartilage explants and did so by modulating the expression of interleukin-1β in primary chondrocyte cultures in vitro. Chondrocalcin was found internalized by chondrocytes. Uptake was found mediated by a single 18-mer peptide of chondrocalcin, which does not exhibit homology to any known cell-penetrating peptide. The isolated peptide, when artificially linked as a tetramer, inhibited gene expression regulation by chondrocalcin, suggesting a functional link between uptake and gene expression regulation. At the same time, the tetrameric peptide potentiated chondrocalcin uptake by chondrocytes, suggesting a cooperative mechanism of entry. The corresponding peptide from type I pro-collagen supported identical cell-penetration, suggesting that this property may be conserved among C-propeptides of fibrillar pro-collagens. Structural modeling localized this peptide to the tips of procollagen C-propeptide trimers. Our findings shed light on unexpected function and mechanism of action of these highly expressed proteins from vertebrates.     

Flavonoids from the leaves and stems of Dodonaea polyandra: a Northern Kaanju medicinal plant

Three prenylated flavonoids 5,7,4'-trihydroxy-3'(3-methylbut-2-enyl)-3-methoxy flavone, 5,7-dihydroxy-3'(3-methylbut-2-enyl)-3,4'-dimethoxy flavone and 5,7,4'-trihydroxy-3',5'(3-methylbuyt-2-enyl)-3-methoxy flavone together with three other known flavonoids were isolated from the medicinal plant Dodonaea polyandra. The plant is used in the traditional medicine system of Northern Kaanju people of Cape York Peninsula, Queensland, Australia. The extracts studied have previously been found to possess anti-inflammatory activity. Successive fractionation of leaf and stem extracts by column and high performance liquid chromatography led to the isolation of these compounds. Their structures were determined using a number of spectroscopic techniques including 1D and 2D NMR and high resolution mass spectroscopy. The structural elucidation is reported herein accompanied by full 1H and 13C NMR spectroscopic data. Spectroscopic data of known compounds was in agreement with that previously reported in literature.     

Extensive settlement of the invasive MEAM1 population of Bemisia tabaci (Hemiptera: Aleyrodidae) in the Caribbean and rare detection of indigenous populations

Bemisia tabaci populations belonging to Middle East-Asia Minor one (MEAM1) and Mediterranean (MED) groups (formerly biotype B and Q, respectively) have spread throughout the world. Although the introduction of MEAM1 is documented from several Caribbean islands, it is generally not known whether MED has also been introduced; whether indigenous populations have survived; and if in the affirmative, to which group(s) they belonged. Whiteflies were collected from seven islands on various plant species. The prevalence of MEAM1 and non-MEAM1 individuals was assessed using a microsatellite approach validated with sequences of the mitochondrial cytochrome oxidase I (mtCOI) gene. Of the 262 samples tested, 247 exhibited the MEAM1 pattern, whereas none showed the MED pattern. The mtCOI gene was partially sequenced from a sample of individuals exhibiting MEAM1 (n = 15) and non-MEAM1 patterns (n = 8) and compared with type sequences. The 15 individuals exhibiting the MEAM1 pattern were confirmed to belong to MEAM1. Of the eight individuals representative of the six non-MEAM1 patterns, two belonged to the indigenous New World (NW) group of B. tabaci (NW), one belonged to a distinct species of Bemisia, and five belonged to MEAM1. One individual belonging to NW exhibited 99.9% nucleotide identity with a NW individual from Puerto Rico. The other was identified as the most divergent individual of the North and Central American genetic cluster. We conclude that a highly homogenous MEAM1 population has extensively settled in the Caribbean and that heterogeneous NW populations were still detectable although severely displaced.     

Variation in patriline reproductive success during queen production in orphaned colonies of the thelytokous ant Cataglyphis cursor

In genetically diverse insect societies (polygynous or polyandrous queens), the production of new queens can set the ground for competition among lineages. This competition can be very intense when workers can reproduce using thelytoky as worker lineages that manage to produce new queens gain a huge benefit. Selection at the individual level might then lead to the evolution of cheating genotypes, i.e. genotypes that reproduce more than their fair share. We studied the variation in reproductive success among worker patrilines in the thelytokous and highly polyandrous ant Cataglyphis cursor. Workers produce new queens by thelytoky in orphaned colonies. The reproductive success of each patriline was assessed in 13 orphaned colonies using genetic analysis of 433 workers and 326 worker-produced queens. Our results show that patrilines contributed unequally to queen production in half of the colonies, and the success of patrilines was function of their frequencies in workers. However, over all colonies, we observed a significant difference in the distribution of patrilines between workers and worker-produced queens, and this difference was significant in three of 13 colonies. In addition, six colonies contained a low percentage of foreign workers (drifters), and in one colony, they produced a disproportionably high number of queens. Hence, we found some evidence for the occurrence of rare cheating genotypes. Nevertheless, cheating appears to be less pronounced than in the Cape Honey bee, a species with a similar reproductive system. We argue that worker reproduction by parthenogenesis might not be common in natural populations of C. cursor.     

The Causal Effect of Vitamin D Binding Protein (DBP) Levels on Calcemic and Cardiometabolic Diseases: A Mendelian Randomization Study

Background

Observational studies have shown that vitamin D binding protein (DBP) levels, a key determinant of 25-hydroxy-vitamin D (25OHD) levels, and 25OHD levels themselves both associate with risk of disease. If 25OHD levels have a causal influence on disease, and DBP lies in this causal pathway, then DBP levels should likewise be causally associated with disease. We undertook a Mendelian randomization study to determine whether DBP levels have causal effects on common calcemic and cardiometabolic disease.

Methods and Findings

We measured DBP and 25OHD levels in 2,254 individuals, followed for up to 10 y, in the Canadian Multicentre Osteoporosis Study (CaMos). Using the single nucleotide polymorphism rs2282679 as an instrumental variable, we applied Mendelian randomization methods to determine the causal effect of DBP on calcemic (osteoporosis and hyperparathyroidism) and cardiometabolic diseases (hypertension, type 2 diabetes, coronary artery disease, and stroke) and related traits, first in CaMos and then in large-scale genome-wide association study consortia. The effect allele was associated with an age- and sex-adjusted decrease in DBP level of 27.4 mg/l (95% CI 24.7, 30.0; n = 2,254). DBP had a strong observational and causal association with 25OHD levels (p = 3.2×10⁻¹⁹). While DBP levels were observationally associated with calcium and body mass index (BMI), these associations were not supported by causal analyses. Despite well-powered sample sizes from consortia, there were no associations of rs2282679 with any other traits and diseases: fasting glucose (0.00 mmol/l [95% CI −0.01, 0.01]; p = 1.00; n = 46,186); fasting insulin (0.01 pmol/l [95% CI −0.00, 0.01,]; p = 0.22; n = 46,186); BMI (0.00 kg/m² [95% CI −0.01, 0.01]; p = 0.80; n = 127,587); bone mineral density (0.01 g/cm² [95% CI −0.01, 0.03]; p = 0.36; n = 32,961); mean arterial pressure (−0.06 mm Hg [95% CI −0.19, 0.07]); p = 0.36; n = 28,775); ischemic stroke (odds ratio [OR] = 1.00 [95% CI 0.97, 1.04]; p = 0.92; n = 12,389/62,004 cases/controls); coronary artery disease (OR = 1.02 [95% CI 0.99, 1.05]; p = 0.31; n = 22,233/64,762); or type 2 diabetes (OR = 1.01 [95% CI 0.97, 1.05]; p = 0.76; n = 9,580/53,810).

Conclusions

DBP has no demonstrable causal effect on any of the diseases or traits investigated here, except 25OHD levels. It remains to be determined whether 25OHD has a causal effect on these outcomes independent of DBP. Please see later in the article for the Editors'' Summary     

Facile and Scalable Preparation of Ruthenium Oxide‐Based Flexible Micro‐Supercapacitors

Tremendous efforts have been invested in the development of the internet of things during the past 10 years. Implantable sensors still need embedded miniaturized energy harvesting devices, since commercialized thin films and microbatteries do not provide sufficient power densities and suffer from limited lifetime. Therefore, micro‐supercapacitors are good candidates to store energy and deliver power pulses while providing non‐constant voltage output with time. However, multistep expensive protocols involving mask aligners and sophisticated cleanrooms are used to prepare these devices. Here, a simple and versatile laser‐writing procedure to integrate flexible micro‐supercapacitors and microbatteries on current‐collector‐free polyimide foils is reported, starting from commercial powders. Ruthenium oxide (RuO₂)‐based micro‐supercapacitors are prepared by laser irradiation of a bilayered tetrachloroauric acid (HAuCl₄ · 3H₂O)–cellulose acetate/RuO₂ film deposited by spin‐coating, which leads to adherent Au/RuO₂ electrodes with a unique pillar morphology. The as‐prepared microdevices deliver 27 mF cm^?2/540 F cm^?3 in 1 m H₂SO₄ and retain 80% of the initial capacitance after 10 000 cycles. This simple process is applied to make carbon‐based micro‐supercapacitors, as well as metal oxide based pseudocapacitors and battery electrodes, thus offering a straightforward solution to prepare low‐cost flexible microdevices at a large scale.     

Population size and habitat associations of the endemic Guadeloupe Woodpecker

ABSTRACT Guadeloupe Woodpeckers (Melanerpes herminieri) are the only endemic bird species on the Caribbean island of Guadeloupe. These woodpeckers were classified as Near Threatened on the IUCN Red List following a population survey in 1994. To reassess the Guadeloupe Woodpecker population, we conducted a new survey in 2007, with 21 transects distributed across eight habitats known to be used by the woodpeckers. Habitats with the highest estimated population densities were seasonal evergreen secondary growth forest, followed by swamp forest and rainforest. Surveys revealed an estimated population of 8469 pairs in 2007 compared to 7368 pairs in 1994, a difference that was not significant. However, our 2007 survey revealed that Guadeloupe Woodpeckers had recolonized the last large patch of available forest on Basse‐Terre, one of the two main islands in the Guadeloupe archipelago. Although our results suggest that the Guadeloupe Woodpecker population has remained relatively stable since 1994, deforestation remains a serious threat and we recommend that the IUCN Red List status of Near Threatened be retained. Management measures that would benefit Guadeloupe Woodpeckers include halting deforestation and providing financial support to people on private land to plant trees and leave dead trees standing. Regular monitoring will be important for determining the possible effects of such measures on the Guadeloupe Woodpecker population.