Orientation of asymmetric stem cell division by the APC tumor suppressor and centrosome

Stem cell self-renewal can be specified by local signals from the surrounding microenvironment, or niche. However, the relation between the niche and the mechanisms that ensure the correct balance between stem cell self-renewal and differentiation is poorly understood. Here, we show that dividing Drosophila male germline stem cells use intracellular mechanisms involving centrosome function and cortically localized Adenomatous Polyposis Coli tumor suppressor protein to orient mitotic spindles perpendicular to the niche, ensuring a reliably asymmetric outcome in which one daughter cell remains in the niche and self-renews stem cell identity, whereas the other, displaced away, initiates differentiation.     

Vesicle endocytosis requires dynamin-dependent GTP hydrolysis at a fast CNS synapse

Molecular dependence of vesicular endocytosis was investigated with capacitance measurements at the calyx of Held terminal in brainstem slices. Intraterminal loading of botulinum toxin E revealed that the rapid capacitance transient implicated as "kiss-and-run" was unrelated to transmitter release. The release-related capacitance change decayed with an endocytotic time constant of 10 to 25 seconds, depending on the magnitude of exocytosis. Presynaptic loading of the nonhydrolyzable guanosine 5'-triphosphate (GTP) analog GTPgS or dynamin-1 proline-rich domain peptide abolished endocytosis. These compounds had no immediate effect on exocytosis, but caused a use-dependent rundown of exocytosis. Thus, the guanosine triphosphatase dynamin-1 is indispensable for vesicle endocytosis at this fast central nervous system (CNS) synapse.     

Interplay of rotational, relaxational, and shear dynamics in solid ⁴He

Using a high-sensitivity torsional oscillator (TO) technique, we mapped the rotational and relaxational dynamics of solid helium-4 ((4)He) throughout the parameter range of the proposed supersolidity. We found evidence that the same microscopic excitations controlling the torsional oscillator motions are generated independently by thermal and mechanical stimulation. Moreover, a measure for the relaxation times of these excitations diverges smoothly without any indication for a critical temperature or critical velocity of a supersolid transition. Finally, we demonstrated that the combined temperature-velocity dependence of the TO response is indistinguishable from the combined temperature-strain dependence of the solid's shear modulus. This implies that the rotational responses of solid (4)He attributed to supersolidity are associated with generation of the same microscopic excitations as those produced by direct shear strain.     

Histologic and immunocytochemical study of endocrine cells in the gastrointestinal tract of the cow and calf

The regional distribution and relative frequency of argyrophil cells, and of cells immunoreactive for 5-hydroxytryptamine (5-HT), substance P (SP), somatostatin, glicentin, glucagon, bovine pancreatic polypeptide (BPP), gastrin, leucine-enkephalin, gastric inhibitory polypeptide (GIP), cholecystokinin, secretin, motilin, and neurotensin were studied in 9 segments from the gastrointestinal tract of cows (greater than 1 year old) and calves (less than 3 months old). Argyrophil cells, 5-HT-immunoreactive cells, and somatostatin-immunoreactive cells were distributed throughout the gastrointestinal tract, whereas the other immunoreactive cells were more restricted in distribution. Most endocrine cells were more numerous in the calf than in the cow. This feature was most conspicuous in the abomasum. In the abomasum, argyrophil cells in the cow and calf and 5-HT-immunoreactive cells in the calf were found predominantly in the fundic region, whereas somatostatin-immunoreactive cells and gastrin-immunoreactive cells in the cow and calf and 5-HT-immunoreactive cells in the cow were most numerous in the pyloric region. Substance P-, glucagon-, BPP-, and leucine-enkephalin-immunoreactive cells were rarely detected. In the small intestine, argyrophil cells, 5-HT-, SP-, somatostatin-, gastrin-, GIP-, cholecystokinin-, secretin-, and motilin-immunoreactive cells were most numerous in the duodenum. Neurotensin-, glicentin-, glucagon-, and BPP-immunoreactive cells were detected with the highest frequency in the ileum. In the large intestine, argyrophil cells and 5-HT-, glicentin-, BPP-, somatostatin-, glucagon-, and SP-immunoreactive cells occurred with the highest frequency in the rectum.     

Winter monsoon promotes the transport of Japanese temperate bass Lateolabrax japonicus eggs and larvae toward the innermost part of Tango Bay,the Sea of Japan

Northwesterly cold winds characteristic of the East Asian Winter Monsoon (EAWM) dictate winter climatic conditions over the Japanese Archipelago. Japanese temperate bass Lateolabrax japonicus is a commercially important coastal fish that spawns offshore in winter and uses shallow waters as nursery habitats. To investigate the effects of EAWM on the planktonic period of L. japonicus, eggs, larvae, and juveniles were quantitatively collected in Tango Bay on the Sea of Japan side in winter and spring from 2007 to 2017. Although eggs occurred close to the mouth of the bay, planktonic larvae occurred further inside as they developed. The horizontal distribution of planktonic larvae, combined with water velocity data obtained from mooring observations, indicated that planktonic larvae are transported south‐ to westward through Ekman current and an anticyclonic circulation, which are driven by northwesterly winds. To evaluate survival during the planktonic period in each year class, the abundance of benthic larvae/juveniles was divided by winter total landings of Lateolabrax spp. (proxy of the spawning stock size). This survival index exhibited a positive correlation with the northwesterly component of winter winds, and a negative correlation with winter air temperature (average from December to February, Spearman's correlation, p < .05). There was, however, no significant correlation with winter water temperature or winter freshwater discharge in the bay. We conclude that northwesterly cold winds of EAWM play a critical role in transporting L. japonicus eggs and larvae toward nursery habitats, specifically beaches and estuaries fringing the innermost part of Tango Bay.     

Studies on availability and fixation of phosphorus in soil (part 4)

It Is known that inorganic phosphorus is contained in soil mainly in the form of calcium phosphates, aluminium phosphates and iron phosphates.     

Identification of the medicinal off-flavor compound formed from ascorbic acid and (E)-hex-2-enal

A test apple beverage made up of apple juice (20%), high-fructose corn syrup (11.5%), citric acid (0.43%), trisodium citrate (0.02%), apple-odor flavor (0.1%), and ascorbic acid (0.02%) was stored at 40 °C and then analyzed for the change of odor in the beverage. Although no thermoacidophilic bacteria (TAB) were detected, a medicinal off-flavor was perceived after the 8 weeks of storage. Model experiments on the ingredients of the test apple beverage revealed that the off-flavor compound had been formed by ascorbic acid and (E)-hex-2-enal. Synthesis and NMR (1H, 13C, HMQC, and HMBC) analyses identified the compound as 6-propylbenzofuran-7-ol. The odor quality, retention index (RI), and mass spectrum of synthetic 6-propylbenzofuran-7-ol were identical with those of the medicinal odor compound from the test apple beverage. Sensory evaluation revealed the recognition thresholds for medicinal odor were 31.4 ppb in water and 24.0 ppb in apple beverage, and the detection thresholds were 19.6 ppb in water and 8.6 ppb in apple beverage, respectively. The quantified concentration of 6-propylbenzofuran-7-ol formed in test apple beverage was 90 ppb, approximately. This concentration was well above the odor threshold, so it was concluded that the compound was the source of the medicinal off-flavor.     

Iron content of rat serum ferritin.

The serum ferritin concentration was significantly higher in female than in male rats, reflecting higher iron stores in females than in males. The mean iron/protein ratio of serum ferritin was 0.018+/-0.008 (SD) (microg of Fe/microg of protein) in female rats and 0.011+/-0.011 in male rats, being much lower than that of liver ferritin (0.233+/-0.014 in females and 0.227+/-0.020 in males). Iron loading of rats significantly increased serum ferritin concentration, but did not influence the iron content of serum ferritin. These results indicate that rat serum ferritin contains only a small amount of iron independent of body iron stores.