How does the curvature of the upper beak bone reflect the overlying rhinotheca morphology?

The beak has independently been evolved accompanied by the edentulism in many tetrapod linages, including extant Testudinata and Aves, and its form and function have been greatly diversified. The beak is formed by beak bones and the overlying keratinous cover, although their profiles are different from each other. Therefore, it is difficult to reliably reconstruct the entire profile of the beak in extinct taxa, whose keratinous tissues are rarely preserved. For elucidation of the morphological relationship between beak bone and overlying keratinous cover, we compared the curvature distribution of the culminal profiles of the upper beak bone and the overlying keratinous cover (rhinotheca) with each other using CT‐scan, in 66 extant testudinatan and avian specimens (Aves: 33 genera, 24 families; Testudinata: 12 genera seven families). In both, rhinotheca and beak bone, the curvature of the profile was nearly constant rostral to a certain point, which was defined as the transition point, and the transition points of the rhinotheca and beak bone were close to each other. The profiles of the rhinotheca and beak bone rostral to their transition point were different in curvature and length. However, the ratio between the curvatures of rhinotheca and the beak bone strongly correlated with the arc angle of the rostral culminal profiles of the beak bone. The upper beak profile in extinct taxa is expected to be reconstructed more reliably using the abovementioned relationship between the beak bone and the rhinotheca.     

Expression and Agonist-Induced Down-Regulation of mRNAs of m2- and m3-Muscarinic Acetylcholine Receptors in Cultured Cerebellar Granule Cells

The regulation and expression of muscarinic acetylcholine receptor (mAChR) mRNA was studied in cultured cerebellar granule cells using Northern blot hybridization, mRNA species for m2- and m3-mAChRs but not m1- and m4-mAChRs were detected in these cells. The expression of mRNAs of both m2- and m3-mAChRs reached a maximum on the tenth day in culture but their expression patterns differed. Treatment of cerebellar granule cells after 8 days in culture with 100 microM carbachol led to differential down-regulation of the mRNA species of both mAChR subtypes present. Muscarinic receptor antagonists, atropine (1 microM) and pirenzepine (10 microM), prevented carbachol-induced m3-mAChR mRNA down-regulation observed at 8 h. However, exposure to either atropine or pirenzepine alone for 8 h led to a significant up-regulation of m3-mAChR mRNA. Thus, the mRNA species for both m2- and m3-mAChR subtypes are differentially expressed in culture and down-regulated by agonist stimulation. The loss of these mRNA species may play a role in the down-regulation of mAChR binding sites that occurs after desensitization.     

Cloning and sequence analyses of vasotocin and isotocin precursor cDNAs in the masu salmon, Oncorhynchus masou: evolution of neurohypophysial hormone precursors.

We have cloned and determined the nucleotide sequences of cDNAs encoding precursors of neurohypophysial hormones, vasotocin (VT) and isotocin (IT), from the hypothalamus of masu salmon, Oncorhynchus masou. The deduced amino acid sequences of masu salmon VT and IT precursors (proVT-I and proIT-I) are highly homologous to those of chum salmon proVT-I and proIT-I, respectively. The VT and IT precursors are composed of a signal peptide, hormone and neurophysin (NP), the middle portion of which is highly conserved among vertebrates. Both the NPs extend about 30 amino acids at the C-terminal. The extended C-terminals have a leucin-rich segment in the carboxyl-terminal, as copeptin of vasopressin precursor. Southern bot analysis showed the presence of two types of proVT genes (proVT-I and proVT-II) and proIT genes (proIT-I and proIT-II) in an individual masu salmon, as in a chum salmon. Southern blot analysis with proVT probes further suggested that at least two different types of proVT-I genes exist in a single masu salmon. Northern blot analysis indicated that proVT-I and proIT-I genes are expressed in the hypothalamus, whereas proVT-II and proIT-II genes are not expressed. Evolutionary distance between proVT-I and proIT-I genes was statistically estimated based on synonymous nucleotide substitution in the coding region of the cDNAs. The magnitude of distance between masu salmon proVT-I and proIT-I genes suggested that the highly conserved central portion of NPs resulted from a gene conversion event. Between masu salmon and chum salmon, evolutionary distance for proVT-I genes is about 6-fold larger than that for proIT-I genes.     

Production of berberine in cultured cells of Coptis japonica

A culture of small fragments of tissues (rootlets) of Coptis japonica on a solid medium followed by successive liquid culture produced friable cell lines with high growth rates and a high berberine content. Light inhibited growth and berberine production in these cell lines whereas high aeration stimulated both.