Mind the wind: microclimate effects on incubation effort of an arctic seabird

The energetic costs of reproduction in birds strongly depend on the climate experienced during incubation. Climate change and increasing frequency of extreme weather events may severely affect these costs, especially for species incubating in extreme environments. In this 3‐year study, we used an experimental approach to investigate the effects of microclimate and nest shelter on the incubation effort of female common eiders (Somateria mollissima) in a wild Arctic population. We added artificial shelters to a random selection of nesting females, and compared incubation effort, measured as body mass loss during incubation, between females with and without shelter. Nonsheltered females had a higher incubation effort than females with artificial shelters. In nonsheltered females, higher wind speeds increased the incubation effort, while artificially sheltered females experienced no effect of wind. Although increasing ambient temperatures tended to decrease incubation effort, this effect was negligible in the absence of wind. Humidity had no marked effect on incubation effort. This study clearly displays the direct effect of a climatic variable on an important aspect of avian life‐history. By showing that increasing wind speed counteracts the energetic benefits of a rising ambient temperature, we were able to demonstrate that a climatic variable other than temperature may also affect wild populations and need to be taken into account when predicting the effects of climate change.     

First report of L1014F kdr mutation in Culex quinquefasciatus in Mexico

The L1014F mutation in the voltage‐sodium channel gene has been associated with resistance to DDT and pyrethroids in various arthropod species including mosquitoes. We determined the frequency of the L1014F kdr mutation in 16 field populations of Culex quinquefasciatus from Northeastern Mexico collected between 2008 and 2013. The L1014F was present in all populations analyzed with the lowest frequency (3.33%) corresponding to the population from Monclova collected in 2012, and the highest frequency (63.63%) from the Monterrey population collected in 2012. The presence of a kdr mutation in populations of Cx. quinquefasciatus from northeastern Mexico provides evidence of pyrethroid resistance. This requires a special attention, considering that pyrethroid‐based insecticides are commonly used in vector‐control campaigns, especially against Aedes aegypti (L.).     

Comparative macroscopic and microscopic anatomical observations on pyloric ceca in some bony fish

The authors report the variable number of pyloric caeca of some species of fish and describe their macroanatomy. They also describe and compare the microanatomy of pyloric caeca in three species; in particular they point out the thickness of tunica muscularis, the shape and length of villi which protrude into the lumen and the variable number of goblet cells. The tunica muscularis is very strong in Uranoscopus and consists of three strata: external and inner longitudinal strata, middle circular stratum. The tunica muscularis is less thick in Diplodus and in Scorpaena. The lamina propria and epithelium form villi which protrude into the lumen. They are covered with columnar epithelium and goblet cells which are more numerous in Uranoscopus and Scorpaena and less numerous in Diplodus. At last the authors describe in pyloric caeca of Scorpaena the presence of a network which engages all the lumen; it consists of connective tissue septa which directly derive from the lamina propria and is covered with the same columnar epithelium and goblet cells.     

Calcium phosphate deposits in domes of human pancreatic adenocarcinoma (Capan-1) cell cultures

Human pancreatic cells of the Capan-1 line form domes in culture during the stationary growth stage. The domes are thought to be a result of the transport of water and electrolytes by the Capan-1 cells. In older Capan-1 cultures, the epithelial sheets formed thickenings from several layers of cells of which the outermost ones were joined by tight type junctions. In the intracellular space, deposits of insoluble calcium salts were observed. Culture of Capan-1 cells in the presence of fibroblasts prolonged survival of the cultures with intact domes for more than 80 days. The Capan-1 cells proliferated forming multilayers and closed cavities which we called super-domes. X-ray spectrometry and electron diffraction analysis showed that the abundant deposits inside these cavities consisted of calcium phosphate in an apatite structure. The number of these deposits increased with time in culture, and they appeared to be formed at the sites of contact with an extracellular matrix consisting of cell debris. Deposits were not observed within the culture medium. Cells from domes were stained cytochemically for ATPases and alkaline phosphatases and examined by light and electron microscopy. The Capan-1 cells surrounding the domes were differentiated, polarized cells containing placental type alkaline phosphatases on their apical membranes and Ca2(+)-ATPases on their basolateral membranes. These enzymes were thought to play a role in the accumulation of phosphate and Ca2+ ions in the dome cavities, which then formed crystals in the presence of organic compounds produced by lysis of cells of the deepest layers of the super-domes. The crystals of hydroxyapatite observed in standard Capan-1 cell cultures and those cocultured with fibroblasts were assumed to be a result of transepithelial transport of Ca2+ and phosphate ions by these cells.     

Comparative study on glucocerebrosidase in spleens from patients with Gaucher disease.

In Gaucher disease (glucosylceramide lipidosis), deficiency of glucocerebrosidase causes pathological storage of glucosylceramide, particularly in the spleen. A comparative biochemical and immunological analysis has therefore been made of glucocerebrosidase in spleens from normal subjects (n = 4) and from Gaucher disease patients with non-neuronopathic (n = 5) and neuronopathic (n = 5) phenotypes. The spleens from all Gaucher disease patients showed markedly decreased glucocerebrosidase activity. Discrimination of different phenotypes of Gaucher disease was not possible on the basis of the level of residual enzyme activity, or by measurements, using the immunopurified enzyme, of kinetic constants, pI or molecular mass forms. A severe decrease was found in the specific activity of glucocerebrosidase purified to homogeneity from the spleen of a patient with the non-neuronopathic phenotype of Gaucher disease, as compared with that of the enzyme purified from the spleen of a normal subject. This finding was confirmed by an immunological method developed for accurate assessment of the relative enzyme activity per molecule of glucocerebrosidase protein. The method revealed that the residual enzyme in the spleens of all investigated patients with a non-neuronopathic course of Gaucher disease had a more than 7-fold decreased activity of glucocerebrosidase (measured in the presence of taurocholate) per molecule of enzyme, and that the concentration of glucocerebrosidase molecules in the spleens of these patients was near normal. Observations made with immunoblotting experiments were consistent with these findings. In contrast, in the spleens of patients with neuronopathic phenotypes of Gaucher disease, the concentration of glucocerebrosidase molecules was severely decreased.     

Carrier detection in a partially dominant X-linked disease: ornithine transcarbamylase deficiency

Summary Ornithine transcarbamylase (OTC) deficiency is an X-linked disease responsible for lethal neonatal hyperammonemia in males. Partial OTC deficiency also occurs in females and can be responsible for life-threatening hyperammonemic comas in heterozygotes (15%). Increased orotic acid excretion occurs in both symptomatic and asymptomatic carriers, especially under protein loading tests. The disease is therefore partially dominant with neonatal lethality in the hemizygous male; the fraction of new mutations has previously been estimated to be low in males (point estimation = 0, upper bound of the confidence interval = 0.16) and 57% in females. Genetic counseling in this disease is difficult because it is not clear whether a negative protein loading test rules out carrier status. In an attempt to determine how reliable the test is for carrier detection, we investigated ten obligate carriers for orotic acid excretion; considering all data available, we concluded that the test is rarely negative in obligate carriers (8%). Consequently, a negative test in a mother decreases the minimum risk of being a carrier from 84% a priori to 30% if she had an affected son and from 43% a priori to 5% if she had a heterozygous daughter. Finally, the diagnosis of a new mutation in the germ cells of the maternal grandfather in one particular family could be ascertained by extensive DNA analysis.     

Observations on enzymes of ammonia assimilation in two different strains of Cyanidium caldarium

Two strains of Cyanidium caldarium, one able to utilize nitrate as a substrate, and the other not, were tested for the presence of enzymes of ammonia assimilation. The nitrate-assimilating strain exhibits glutamate dehydrogenase activity. By contrast, the other strain lacks glutamate dehydrogenase; it possesses high alanine dehydrogenase and l-alanine aminotransferase activities which suggest that this strain may incorporate ammonia through reductive amination of pyruvate and may form glutamate from 2-ketoglutarate by a transamination reaction with alanine. Neither strain reveals glutamate synthase activity. Both strains contain similar levels of glutamine synthetase.     

Substances of plant flowering

The investigation of the hormonal nature of plant flowering in connection with their photoperiodic reaction has shown that flowering depends on a bicomponental system of hormones, gibberellins regulating stem formation and growth and substances of the anthesin type regulating flower formation. In agreement with the division of the photoperiodic reaction into a leaf and a stem phase the study of the internal factors acting on plant flowering was carried out by means of leaf and stem (apex, bud and callus) models. The results obtained from work with leaf models proved the presence of two groups of hormones of flowering in plants. The data obtained from the application of stem models pointed to the localization of the action of gibberellin and anthesin in different zones of the shoot apices and characterized the potential capacity for flower formation of isolated callus tissue of neutral and photoperiodically sensitive species.