The critical period for thyroid hormone responsiveness through thyroid hormone receptor isoform α in the postnatal small intestine

During second and third weeks after birth in rats, serum thyroid hormone level is elevated. In this study, we investigated the jejunal expression of thyroid hormone receptor (TR) α in developing rats. The TRα-1 mRNA level and TRα-1/TRα-2 mRNA ratio increased two-fold from 5 to 13 days after birth. This high level of TRα-1 mRNA was maintained until 20 days and then decreased to the basal level by the end of weaning period at 27 days; however, the level of TRα-2 mRNA remained unchanged throughout the developmental period. The increase in the TRα-1/TRα-2 mRNA ratio from 5 to 13 days was accompanied by an initial rise in the levels of mRNA for hexose transporters in the jejunum. Administration of T₃ during the suckling period (8–13 days) caused a 50% increase in the TRα-1/TRα-2 mRNA ratio, while administration of T₃ on days 12–17 and days 16–21, but not on days 22–27, caused a two to four-fold increase in the levels of mRNA for hexose transporters. These results suggest that a transient variation in the TRα-1/TRα-2 expression ratio is closely related to the critical period of thyroid hormone responsiveness for hexose transporters expression in the developing rat jejunum.     

Dietary supplementation with epigallocatechin gallate elevates levels of circulating adiponectin in non-obese type-2 diabetic Goto-Kakizaki rats

Epigallocatechin gallate (EGCG) reportedly enhances plasma adiponectin levels in models of insulin resistance and obesity. In this study, we found that EGCG increases plasma adiponectin levels and decreases plasma triacylglycerol levels in non-obese diabetic Goto-Kakizaki rats with insulin secretory dysfunction. These results suggest that EGCG ameliorates lipid metabolic abnormality even in non-obese rats, probably by increasing adiponectin production.     

Stable kinetochore–microtubule attachments restrict MTOC position and spindle elongation in oocytes

In mouse oocytes, acentriolar MTOCs functionally replace centrosomes and act as microtubule nucleation sites. Microtubules nucleated from MTOCs initially assemble into an unorganized ball‐like structure, which then transforms into a bipolar spindle carrying MTOCs at its poles, a process called spindle bipolarization. In mouse oocytes, spindle bipolarization is promoted by kinetochores but the mechanism by which kinetochore–microtubule attachments contribute to spindle bipolarity remains unclear. This study demonstrates that the stability of kinetochore–microtubule attachment is essential for confining MTOC positions at the spindle poles and for limiting spindle elongation. MTOC sorting is gradual and continues even in the metaphase spindle. When stable kinetochore–microtubule attachments are disrupted, the spindle is unable to restrict MTOCs at its poles and fails to terminate its elongation. Stable kinetochore fibers are directly connected to MTOCs and to the spindle poles. These findings suggest a role for stable kinetochore–microtubule attachments in fine‐tuning acentrosomal spindle bipolarity.     

Analysis of the formation mechanism for thermoresponsive-type coacervate with functional copolymers consisting of N-isopropylacrylamide and 2-hydroxyisopropylacrylamide

We now report the formation mechanism of the thermoresponsive-type coacervate with the novel functional temperature-sensitive polymer, poly(N-isopropylacrylamide-co-2-hydroxyisopropylacrylamide) (poly(NIPAAm-co-HIPAAm)), synthesized in our laboratory. The effects of introducing the hydrophilic comonomer (HIPAAm) into the copolymer chains and adding salts on the behaviors of the coacervate droplets induced in the poly(NIPAAm-co-HIPAAm) aqueous solutions were investigated. Not only the particle sizes of the coacervate droplets but also the cloud points of the copolymer solutions could be modulated by the HIPAAm content incorporated in the copolymers. Moreover, the particle sizes of the coacervate droplets were also changed by adding salts. Namely, the particle sizes increased with the decreasing HIPAAm composition and increasing NaCl concentration. In addition, the 1H NMR and differential scanning calorimetric measurements suggested that as the HIPAAm content decreased or NaCl concentration increased, dehydration of the copolymers induced in the phase transition and/or separation became much easier. Therefore, on the basis of the findings obtained from these measurements, we determined that the particle sizes of the coacervate droplets induced in the temperature-sensitive polymers increased as the number of the water molecules, which are dissociated from the polymeric chains during the phase transition and/or separation, increased. Besides, to examine the separation of the model solutes, the aqueous two-phase separation with the coacervate droplets of poly(NIPAAm-co-HIPAAm) was carried out. The partitions of Methyl Orange as a model solute under both acidic (pH 2) and basic (pH 12) conditions were performed. The amount of Methyl Orange partitioned into the coacervate droplets at pH 12 is much greater than that at pH 2, which indicated that the coacervate droplets could recognize a slight difference in the polarity or structure between the model solutes.     

Development and Transduction of Rsistance to Novobiocin and Nikkol-SNP 7.5 A (an Anionic Surfactant) in Staphylococcus aureus

The susceptibility to Novobiocin (NB) and Nikkol-SNP 7.5 A (NS), an anionic surfactant, was studied in 458 strains of coagulase-positive Staphylococcus aureus isolated from clinical sources. Twenty three (4.9%) of these strains were resistant to NB with minimum inhibition concentration (MIC) of 1.6 μg per ml or more, 97 (21.2%) resistant to NS with MIC of 6.25 mg per ml or more, and 17 (3.7%) resistant to both drugs. Cross-resistance to NB and NS was found in 74 per cent of 23 NB-resistant strains and 17.5 per cent of 97 NS-resistant strains. Nearly one half of NS-resistant strains belonged to phase group I, while the remainder were non-typable. The majority of the NB-resistant strains were not phage typable. In S. aureus strain PS 53 used for propagating phage 53, resistance to 25 mg per ml of NS was attained rapidly by single step without accompanying that to NB, whereas resistance to 25 μg per ml of NB developed gradually by three successive steps and was accompanied by a rapid development of resistance to NS first by two steps. The transduction experiments in strain PS 53 showed that resistance to NB and NS was jointly transduced and the genetic loci responsible for resistance to both drugs are closely linked.     

A study of the chromosomes of thirty-four species of Japanese weevils (Coleoptera:Curculionidae)

The chromosomes of 34 Japanese weevils belonging to 13 subfamilies were investigated in male and/or female germ line cells using squash preparations with the exception of one species studied by sectioning. The results are summarised in Table 1. Excluding two species with Neo-XY, the other 32 species have an Xy_p sex-determining mechanism.

     

Antibacterial activity of cefpodoxime against Branhamella catarrhalis.

The antibacterial activity of cefpodoxime against Branhamella catarrhalis was studied. All of the 65 clinical isolates tested were inhibited at and below 1.56 micrograms/ml, both at 10(7) and at 10(5) CFUs. The following was further studied on B. catarrhalis N-5 which showed average susceptibility to each drug examined. Bactericidal activity was observed at and above the MIC. Scanning and transmission electron microscopy revealed morphological changes, such as cellular swelling, bleb formation, inhibition of septum formation, and lysis, of the cells exposed to cefpodoxime at concentrations around the MIC. Cefpodoxime was poorly hydrolyzed by the beta-lactamase and it showed affinity for two penicillin-binding proteins that had approximate molecular weights of 83 and 74 kilodaltons, with I50 values of 3.7 and 2.1 micrograms/ml, respectively.     

On the chromosomes of the bisexual weevils of the genus Catapionus (Curcilionidae: Coleoptera)

The chromosomes of three Japanese weevil species of the genus Catapionus were studied in male and female germ line cells.