Response of a neotenic goby,ice goby (Leucopsarion petersii), to thyroid hormone and thiourea treatments

In order to clarify the mechanisms of neoteny in the ice goby (Leucopsarion petersii), we examined effects of thyroid hormone and thiourea (TU) treatments on their neotenic characteristics and the pituitary-thyroid axis. Adult ice goby were exposed to 3, 5, 3'-triiodothyronine (T3, 0.1 ppm), TU (inhibitor of thyroid hormone synthesis, 30 ppm), or the combination of the two for 2 weeks. Observations of whole body T3 levels, thyroid follicles and TSH immunoreactive cells in the pituitary suggests the presence of a functioning thyroidal system. However, all of the neotenic features did not disappear in T3-treated fish, suggesting the absence of T3 responsiveness in peripheral tissues. These results indicate the similarity between neoteny of the ice goby and obligatory-type neoteny of urodeles.     

TAK-599, a novel N-phosphono type prodrug of anti-MRSA cephalosporin T-91825: synthesis,physicochemical and pharmacological properties

Crystalline 1 (TAK-599) is a novel N-phosphono prodrug of anti-methicillin-resistant Staphylococcus aureus (MRSA) cephalosporin 2a (T-91825) that has high affinity for penicillin-binding protein (PBP) 2' (IC(50); 0.90 microg/mL) and shows potent in vitro anti-MRSA activity (MIC against MRSA N133; 1.56 microg/mL), comparable to that of vancomycin (1.56 microg/mL). Although 2a had insufficient water solubility (2.3 mg/mL) for parenteral administration, 1 showed excellent water solubility (>100 mg/mL, pH 7) as well as good chemical stability in the solid state and solution. In pharmacokinetic studies, when 1 was administered intravenously to rats and monkeys, it was rapidly converted into 2a in the blood. These results show that 1 (TAK-599) is a highly promising parenteral cephalosporin targeted for MRSA infection.     

The Spawning and Early Development of the Hawaiian Acorn Worm (Hemichordate), Ptychodera flava

The spawning and early embryogenesis of the hemichordate, Ptychodera flava, in Hawaii are described in detail and illustrated with photographs of living material. Natural spawning in the evenings of early December was induced by a shift of seawater temperature from about 22 degrees C to about 26 degrees C. The fertilized egg divides equally and slowly at first, reaching 8 cells at about 5 hr after insemination at room temperature (20-24 degrees C). Divisions then appear to become slightly unequal and by 9 hr the embryo has divided into about 100 cells. The blastocoel forms during cleavage as an irregular space that, when viewed from the side, tends to appear oblate and ultimately appear crescent-shaped as the vegetal plate thickens into the blastocoel. The archenteron forms at about 18 hr as a cleft beginning at the vegetal pole and extending into the vegetal plate. As development proceeds, the embryo expands and by 24 hr forms a typical deuterostome gastrula with an outer sphere of ectoderm and a inner tube of endoderm connected at the blastopore. An out-pocketing of the gut appears at the tip of the archenteron over the next 4 hr to form the protocoel which will become the proboscis coelom. Approaching 40 hr the gut becomes asymmetric and over the next few hr contacts the ectoderm to form a mouth. Hatching occurs during this time at about 45 hr of development. Morphogenesis continues to produce an early tornaria larva by about 60 hr.     

Temporal changes in liver carbohydrate metabolism associated with seawater transfer in Oreochromis mossambicus

The metabolic aspects of ionic and osmotic regulation in fish are not well understood. The objective of this study was to examine changes in carbohydrate metabolism during seawater (SW) acclimation in the euryhaline tilapia (Oreochromis mossambicus). Hepatic activities of three key enzymes of the intermediary metabolism, phosphofructokinase, glycogen phosphorylase and glucose 6-phosphate dehydrogenase, together with glycogen content and plasma glucose concentration were measured at 0, 0.5, 1, 2, 3, 6, 12, 24, 48 and 96 h after the direct transfer of tilapia from fresh water (FW) to 70% SW. Plasma growth hormone, prolactin₁₇₇ and prolactin₁₈₈, Na⁺ and Cl⁻ concentrations were also measured. Plasma Na⁺ and Cl⁻ levels were highest at 12 h, but returned to FW levels at 24 h after transfer, suggesting the tilapia were able to osmoregulate within 24 h after transfer. Plasma glucose levels were significantly higher in 70% SW than in FW during the course of acclimation, especially in the early stages. Hepatic enzyme activities and glycogen content did not change significantly during the acclimation period. Our results suggest the possibility that glucose is an important energy source for osmoregulation during the acclimation to hyperosmotic environments in O. mossambicus.     

A histochemical study of the innervation of cerebral blood vessels in the snake

Summary Dual innervation of snake cerebral blood vessels by adrenergic and cholinergic fibres was demonstrated with the use of histochemical methods. Although the nerve plexuses are somewhat less dense, the essential features of innervation of the blood vessels are similar to those of mammals with the exception that the adrenergic plexuses are more prominent than the cholinergic plexuses. The major arteries of the cerebral carotid system have a rich nerve supply. However, the innervation is less rich in the basilar and poor in the spinal (vertebral) arteries. Although the arteries supplying the right side of head are poorly developed, three pairs of arteries, cerebral carotids, ophthalmics and spinals, supply the snake brain. The carotids and ophthalmics are densely innervated and are accompanied by thick nerve bundles, suggesting that the nerves preferentially enter the skull along those arteries. Some parenchymal arterioles are also dually innervated. Connection between the brain parenchyma and intracerebral capillaries via both cholinergic and adrenergic fibres was observed. In addition cholinergic nerve fibres, connecting capillaries and the intramedullary nerve fibre bundles, were noticed. Capillary blood flow may be influenced by both adrenergic and cholinergic central neurons. The walls of capillaries also exhibit heavy acetylcholinesterase activity. This may indicate an important role for the capillary in the regulation of intracerebral blood flow.     

Extraordinarily stable mini-hairpins: electrophoretical and thermal properties of the various sequence variants of d(GCGAAAGC) and their effect on DNA sequencing.

A small DNA fragment having a characteristic sequence d(GCGAAAGC) has been shown to form an extraordinarily stable mini-hairpin structure and to have an unusually rapid mobility in polyacrylamide gel electrophoresis, even when containing 7M urea. Here, we have studied the stability of the various sequence variants of d(GCGAAAGC) and the corresponding RNA fragments. Many such sequence variants form stable mini-hairpins in a similar manner to the d(GCGAAAGC) sequence. The RNA fragment, r(GCGAAAGC) also forms a mini-hairpin structure with less stability. The DNA mini-hairpins with GAAA or GAA loop are much more stable than DNA and RNA mini-hairpins with other loop sequence so far as has been examined. The stability difference between DNA and RNA mini-hairpins may be deduced to the stem structures formed by DNA (B form) and RNA (A form). The stable hairpins consisting of the GCGAAAGC sequence cause strong band compression on the sequencing gel. This phenomenon should be carefully considered in DNA sequencing.     

Development and neural organization of the tornaria larva of the Hawaiian hemichordate, Ptychodera flava

We report scanning and transmission electron microscopic studies of the early development of the Hawaiian acorn worm, Ptychodera flava. In addition, we provide an immunohistochemical identification of the larval nervous system. Development occurs and is constrained within the stout chorion and fertilization envelope that forms upon the release of the cortical granules in the cytoplasm of the egg. The blastula consists of tall columnar blastomeres encircling a small blastocoel. Typical gastrulation occurs and a definitive tornaria is formed compressed within the fertilization envelope. The young tornaria hatches at 44 hr and begins to expand. The major circumoral ciliary band that crosses the dorsal surface and passes preorally and postorally is well developed. In addition, we find a nascent telotroch, as well as a midventral ciliary band that is already clearly developed. The epithelium of tornaria is a mosaic of monociliated and multiciliated cells. Immunohistochemistry with a novel neural marker, monoclonal antibody 1E11, first detects nerve cells at the gastrula stage. In tornaria, 1E11 staining nerve cells occur throughout the length of the ciliary bands, in the apical organ, in a circle around the mouth, in the esophageal epithelium and in circumpylorus regions. Axon(s) and apical processes extend from the nerve cell bodies and run in tracks along the ciliary bands. Axons extending from the preoral and postoral bands extend into the oral field and form a network. The tornaria nervous system with ciliary bands and an apical organ is rather similar to the echinoderm bipinnaria larvae.     

Expression of the fetal-oncogenic fibroblast growth factor-8/17/18 subfamily in human hematopoietic tumors

The fibroblast growth factors (FGFs) are involved in hematopoiesis and tumorigenesis. However, little is known about the contribution of the FGFs identified within the past 10 years to leukemogenesis. To elucidate whether these FGFs (FGF-8, -9, -10, -11, -12, -13, -14, -16, -17, -18, -19, -20, and -21) are expressed in leukemic cells, we performed RT-PCR analyses using 28 cell lines. The members of a fetal-oncogenic subfamily, FGF-8/-17/-18, were often expressed (53.5%, 25.0%, and 32.1%) with the co-expression of their receptors. Realtime quantitative-PCR analysis showed that FGF-8/-17 were aberrantly expressed in patients with acute leukemia. Moreover, cell proliferation assays revealed the proliferation activity of FGF-17 on leukemic cells expressing its receptors. These results demonstrated that certain recently identified FGFs play an important role in the growth of leukemic cells, possibly with an autocrine mode of action, and that these FGFs will become novel biomarkers for hematopoietic tumors.     

Roles of endogenous cytokines in liver apoptosis of mice in lethal Listeria monocytogenes infection

Various bacterial pathogens have been identified as mediators of apoptosis. Apoptosis reportedly shows both detrimental and beneficial effects on biological functions. We studied the role of liver apoptosis in lethal Listeria monocytogenes infection and the regulation of apoptosis by endogenous cytokines during infection. Apoptosis was observed in the spleen but not in the liver of infected mice, whereas the induction of liver necrosis was evident by rising levels of serum aminotransferases in these animals. Apoptosis was detected in the liver of L. monocytogenes-infected mice which had been treated with monoclonal antibody (mAb) against tumor necrosis factor-alpha (TNF-alpha) or interleukin-6 (IL-6), or in TNF-alpha(-/-) mice, but not in gamma- interferon (IFN-gamma)(-/-) mice or mice which had been treated with mAb against IL-4 or IL-10. Augmentation of liver apoptosis in mice treated with mAb against TNF-alpha or IL-6 or in TNF-alpha(-/-) mice correlated with the increase in bacterial numbers in the organ, while no augmentation of apoptosis was observed in the liver of IFN-gamma(-/-) mice irrespective of the marked increase in bacterial numbers in the organs, indicating that augmentation of liver apoptosis may not be merely due to the increase in bacterial growth in the organs. These results suggest that TNF-alpha and IL-6 may play an important role in protecting the liver from apoptosis in lethal L. monocytogenes infection.