Biliverdin IX delta and neobiliverdin IX delta, isolated from the ovaries of the marine snail, Turbo cornutus

The ovaries of the marine snail Turbo cornutus contain a number of pigments. So far, the presence of carotenoids and a chromoprotein with a bile pigment, called turboverdin (= 3(2)-hydroxy-mesobiliverdin IX alpha), as its prosthetic group are known. The present work describes the isolation and structure elucidation of two further bile pigments, biliverdin IX delta and neobiliverdin IX delta. This is the first report of naturally occurring bile pigments with IX delta structure.     

Immunogenic protein MPB57 from Mycobacterium bovis BCG: molecular cloning, nucleotide sequence and expression

Using a single-probe method, we have cloned the gene for an immunogenic MPB57 protein of Mycobacterium bovis BCG. The nucleotide sequence includes an ORF of 300 base pairs encoding a protein of 99 amino acids with an Mr of 10,818. This cloned gene was expressed in an Escherichia coli expression vector to give a mature protein which reacted with a polyclonal antibody raised against MPB57.     

Biochemical evidence for the local synthesis and retention of fibronectin in the tissue of human placenta

1. Human chorionic tissues were incubated with [14C]leucine and/or [3H]glucosamine, and fibronectin synthesis was examined. 2. Radio-labeled fibronectin was detected in the tissue fraction of the incubation mixture, but not in the medium fraction, indicating that fibronectin is synthesized and retained in the tissue. 3. The glycopeptides derived from 3H-labeled fibronectin showed the lectin-binding characteristics similar to those from unlabeled placenta fibronectin, but different from those of plasma fibronectin.     

To what extent does a minimal atherosclerotic plaque alter the arterial wall shear stress distribution? A model study by an electrochemical method

An electrochemical surface shear stress measurement was applied to a model of very thin unilateral arterial stenosis (height of 1/8 of the model pipe diameter with very smooth surface). Three dimensional wall shear stress distribution was measured under steady flow field from a relatively low Reynolds number, Re = 270, to a high Reynolds number, Re = 1200. There was a characteristic high and low wall shear distribution pattern around the stenosis. There were also remarkable high shear stress areas on the opposite wall and both side walls of the stenosis. It was clearly shown that three dimensional structure of the flow field, hence, the wall shear stress distribution, is affected by a minimal change on the arterial wall.     

Alpha-interferon treatment for adult T cell leukemia: low levels of circulating alpha-interferon and it's clinical effectiveness

We describe a patient with adult T cell Leukemia to whom alpha-interferon therapy was highly effective. Although a combination chemotherapy (ACVP) first introduced was effective in reducing total leukocyte counts, the percentage of leukemic cells relative to total leukocyte counts was decreased first after the institution of alpha-interferon therapy. The patient is now under complete remission for four years. It was noted in this patient that circulating alpha-interferon, measured by a sensitive radioimmunoassay, was consistently low as compared with the value found in the age-, sex-matched healthy control (p less than 0.001). Since adult T cell leukemia is pathogenetically related to the retrovirus infection, low levels of circulating alpha-interferon of the patient may be important from both pathogenetic and therapeutic standpoints. Alpha-interferon therapy may be an useful additive for the chemotherapy of adult T cell leukemia.     

Analysis of the replication mode of double minutes using the PCC technique combined with BrdUrd labeling

A cultured line of neuroblastoma cells (NB) was found to contain double minute chromosomes (DMs). DMs have been reported to be acentric and, therefore, to be segregated randomly into daughter cells without separating their sister elements. When NB cells were fused with Chinese hamster metaphase cells, prematurely condensed chromosomes (PCCs) were induced. DMs seen together with G₂ PCCs appeared to be closely paired, dot-like structures resembling DMs observable in metaphase cells. In contrast, DMs in G₁ cells showed a tendency to become single as the stage progressed so that the majority of DMs in late G₁ cells were actually no longer double. DMs in S-phase cells, however, again appeared double. These results clearly indicate why DMs are invariably double and never assume a quadruple configuration in metaphase cells in spite of their non-disjunctional segregation at anaphase. Such a characteristic mode of DM replication was further confirmed by a 5-bromo-2-deoxyuridine (BrdUrd) labeling experiment: when NB cells were exposed to BrdUrd for two successive rounds of DNA replication prior to PCC induction, half of the resulting single G₁ minutes as well as G₁ PCCs stained dark and the other half stained light after staining for sister chromatid differentiation.     

Role of high-density lipoprotein in transport of circulating bilirubin in rats

The analbuminemic rat strain established by Nagase et al. (Nagase, S., Shimamune, K., and Shumiya, S. (1979) Science 205, 590-591) exhibits hereditary deficiency in albumin biosynthesis. Serum bilirubin concentration is rather lower in homozygous (aa) rats (0.009 +/- 0.002 mg/dl) as compared with heterozygous (Aa) rats (0.047 +/- 0.009 mg/dl) or wild-type Sprague-Dawley (AA) rats (0.034 +/- 0.006 mg/dl) as evidenced by high pressure liquid chromatography analysis of bilirubin. After intravenous administration of various amounts of [heme-3H]hemoglobin in rats, [3H]bilirubin derived from [3H]heme of hemoglobin in vivo is more efficiently excreted into bile in aa rats than in Aa or AA rats. [3H]Bilirubin is exclusively bound with high-density lipoprotein (HDL) in aa rats, and a significant amount of [3H]bilirubin is shown to bind with HDL in Aa or AA rats in vivo. Scatchard plots revealed that [3H]bilirubin is bound with HDL in three binding modes depending on the molar ratio of [3H]bilirubin to HDL: Kd = 0.8 X 10(-7) M (molar ratio, 0.02-0.06), Kd = 1.6 X 10(-6) M (molar ratio, 0.06-0.41), and Kd = 1.2 X 10(-4) M (molar ratio, 0.79-9.02). Even under extreme conditions of excess hemoglobin administration, the molar ratio remains under 0.041; and thus, expected the Kd value would remain around 0.8 X 10(-7) M. Binding of [3H]bilirubin to rat serum albumin revealed two distinct binding modes depending on the molar ratio of [3H]bilirubin to rat serum albumin: Kd = 3.6 X 10(-7) M (molar ratio, 0.03-0.21), and Kd = 5.0 X 10(-6) M (molar ratio, 0.21-2.46). Under physiological conditions in Aa or AA rats, the former mode would be more reliable than the latter. Thus, HDL could bind with approximately 4.5 times higher affinity than rat serum albumin in Aa or AA rats under physiological conditions in vivo.     

Single transient K channels in mammalian sensory neurons.

A single-channel recording of the transient outward current (A-current) was obtained from dorsal root ganglion cells in culture using patch-clamp techniques. Depolarization of the membrane patch elicited pulse like current of a uniform amplitude in an outward direction, of which the unitary conductance was 20 pS. Alteration of extracellular ionic compositions indicated that the charge carriers were K ions. A systematic study was made on the voltage-dependence of the ensemble average current; (a) the activation started at a potential around -60 mV; (b) the time course of the activation was relatively rapid; (c) the channel was completely inactivated at a potential positive to -40 mV. Two time constants (tau f = 100 ms and tau s = 4,000 ms) were detected in the decay of the current indicating that the channels had two different states of inactivation. A convulsant, 4-aminopyridine (4-AP), acted on the channel only from the intracellular side of the membrane. 4-AP (5 mM) reduced not only mean open time (by 50%) but also the single-channel conductance (by 20%). The properties of the channel were independent of Ca ions in the intracellular space.     

High-order structure of metaphase chromosomes: evidence for a multiple coiling model

When chromosome preparations made by the conventional air-drying method were processed with the OsO₄/TCH technique and examined by scanning electron microscopy (SEM), spiral structures in chromatids, which have been frequently observed to be present by light microscopy, were found to be composed of 30 nm fibres. In some portions these fibres appeared to be arranged in coils to form thicker fibres. When chromosome preparations were processed for SEM without air drying, chromosomes appeared to consist of fairly homogeneous thick fibrous structures measuring about 200 nm in diameter. In relatively condensed chromosomes, these 200 nm fibres appeared to be arranged perpendicular to the long axis of the chromatid. These findings suggest that chromatid spiral structures represent a regularly loosened state of the compactly spiralized 200 nm fibres which in turn consist of spiralized 30 nm fibres.     

Fractionation and Estimation of Particle-Attached and Unattached Bradyrhizobium japonicum Strains in Soils

Rhizobial cells attached or unattached to soil particles were estimated. Nonsterile soils into which antibiotic-resistant mutants of Bradyrhizobium japonicum had been introduced were fractionated by a centrifugation technique into two fractions: A, which contained mainly rhizobial cells attached to soil particles, and F, which contained mainly rhizobial cells unattached to them. Rhizobial counts decreased in both fractions during incubation of the soil at 30°C, with a concomitant decrease in the proportion of the count of fraction F to that of fraction A. Sonication of fraction A of the soil incubated for more than 3 weeks caused an increase in the rhizobial count. The ratio of the count of fraction A estimated by the plant infection method to that estimated by the dilution plate method increased after 5 days of soil incubation. More than 90% of the indigenous rhizobia in an agricultural field existed in fraction A. These results suggest that the majority of rhizobial cells are attached to soil particles.