Diverging phenological responses of Arctic seabirds to an earlier spring

The timing of annual events such as reproduction is a critical component of how free‐living organisms respond to ongoing climate change. This may be especially true in the Arctic, which is disproportionally impacted by climate warming. Here, we show that Arctic seabirds responded to climate change by moving the start of their reproduction earlier, coincident with an advancing onset of spring and that their response is phylogenetically and spatially structured. The phylogenetic signal is likely driven by seabird foraging behavior. Surface‐feeding species advanced their reproduction in the last 35 years while diving species showed remarkably stable breeding timing. The earlier reproduction for Arctic surface‐feeding birds was significant in the Pacific only, where spring advancement was most pronounced. In both the Atlantic and Pacific, seabirds with a long breeding season showed a greater response to the advancement of spring than seabirds with a short breeding season. Our results emphasize that spatial variation, phylogeny, and life history are important considerations in seabird phenological response to climate change and highlight the key role played by the species’ foraging behavior.     

Behavioural response of a whale shark during the passage of a typhoon

During a behavioural survey of a tagged whale shark (Rhincodon typus) conducted in 2019 in the waters off Kagoshima, Japan, a typhoon passed close to the area under surveillance. As the typhoon approached, monitoring of the shark's movements indicated that it dived to depths of up to 90 m, and during this period, the authors recorded the effects of the typhoon-induced waves. They also detected changes in the vertical thermal structure of the waters, possibly due to the disturbance caused by the typhoon.     

Reproductive success is strongly related to local and regional climate in the Arctic snow bunting (Plectrophenax nivalis)

Polar Biology - Global climate change is regarded as one of the major threats to biodiversity. Both local and regional climate parameters can have strong effects on ecological processes affecting...     

Oscillations in Yeast Observed Electrically

It has previously been demonstrated that oscillations occur in actively growing yeast cultures. These oscillations occur because yeast cells synchronize their glycolytic pathway following a saturation period. Periodic changes in the levels of intermediate metabolites in glycolysis as well as changes in pH ofthe media have been measured, that demonstrate this phenomenon. Here we observe that the conductivity of the media also changes periodically when yeast cells are cultured under similar conditions. As conductivity is easily measured, this provides a simple, more quantitative method to study these changes than those currently used. An electrical biosensor referred to as ECIS (electrical cell surface impedance sensing) was used to study the small conductivity changes (in the order of 0.1%). No significant differences in the observed periods were found in the two yeast strains or the commercially purchased yeast extract studied.     

Direct reduction of NAD+ by electrochemical procedure and application of the regenerated NADH to enzyme reaction

Summary Enzymatically active NADH was formed from NAD⁺ directly in the electrochemical system by adopting an anion-charged membrane as a diaphragm and applying the less cathodic potential of –0.7V vs. Ag/AgCl electrode. The direct electrochemical procedure worked favorably as an NADH regenerator in the biochemical reaction system using D-lactate dehydrogenase which transforms pyruvate to D-lactate.     

Expression of inhibin α-subunit gene during mouse gametogenesis

Mammalian gametogenesis is regulated through complex interactions between germ and somatic cells. To investigate the mechanism underlying the differentiation of functional gametes, some genes specifically expressed during gametogenesis have been isolated and characterized. In a search for further examples of such genes, we have isolated from a newborn mouse testis cDNA library, a clone corresponding to mouse inhibin alpha-subunit. Although it is known that the inhibin alpha-subunit molecule is abundantly produced in ovarian follicle and in testicular Sertoli cells, the spatial and temporal patterns of expression of this gene remain to be elucidated. In this study, the patterns of expression of inhibin alpha-subunit mRNA during mouse gametogenesis were examined by RNA blot, cytoplasmic dot and in situ hybridization techniques. In the testis, the concentration of inhibin alpha-subunit mRNA increased from about 16 dpc (days post coitum), peaked at birth and then gradually decreased, paralleling testicular development. Inhibin alpha-subunit mRNA was localized in Sertoli cells of wild type as well as W/Wv testes. In adult testis, mRNA was restricted to the perinuclear cytoplasm of Sertoli cells. Inhibin alpha-subunit mRNA was expressed in follicle cells of adult ovary more abundantly than in adult testis. Analysis of expression during folliculogenesis showed that the accumulation of this mRNA began in preantrum follicles and the level of expression reached a maximum in Graafian follicles.     

Effect of gossypol on the ultrastructure of rat spermatozoa

Summary Gossypol was found to induce sterility in male rats when administered orally. A reduction in the number of spermatozoa in the epididymis from the gossypol-treated rats was observed when compared to the control animals. An examination of the spermatozoa from the treated rats showed the following ultrastructural modifications: disorganization of the mitochondrial sheath and missing cell membrane from the middle piece, broken cell membrane and missing members of both outer fibers and inner microtubules of the principal piece, and broken cell membrane of the sperm head. Serial mating experiments proved that gossypol-treated males were indeed sterile. The results suggest that gossypol at low concentrations is able to affect the motility of spermatozoa, thus contributing to its contraceptive action.