[Identification of streptavidin]

In this report, streptavidin (SA) was further identified on the basis of our previous researches in SA isolation and purification. 23.2 mg of SA productivity could be obtained after purification by DEAE-52 column from 1 L of culture supernatant. The spectrum scanning of ultraviolet absorption was congruent with that of the Sigma product. 2 bands appeared on the SDS-PAGE electrophoresis of SA. The molecular weight of SA was 72 881 Dalton with PI 6.0; the averaged biotin-binding activity was 18 micrograms/mg. The results confirmed that the methods of isolation and purification of SA developed by authors were reliable for immunological application.

Color changes in dry-pigmented maxillofacial elastomer resulting from ultraviolet light exposure

Five dry pigments and one maxillofacial elastomer were evaluated for color changes (delta E) resulting from prolonged exposure to two types of ultraviolet light. The elastomer, pigments, and pigmented elastomers were subjected to each ultraviolet light source for 400, 600, and 1800 hours, and delta E color shifts were determined. The unpigmented elastomer underwent minimally perceptible color change after 600 hours of exposure to both types of ultraviolet light. Two pigments underwent substantial color change after 400 hours, whereas the remaining three pigments remained color stable after 1800 hours. It was concluded that for the materials tested, early color changes in a prosthesis may be the result of degradation of certain ultraviolet light-susceptible pigments, whereas longer term color shifts may be caused by color changes within the elastomer.

[Isolation and identification of extrem thermophilic bacteria from hot springs of Sichuan and Tibet]

Eleven strains of extrem thermophilic bacteria belonging to the Bacillus Stearothermophiles were isolated from the hot springs of Sichuan and Tibet. The cells were gram-positive, sporulating and motile. The optimum temperature for growth was between 65 degrees C to 70 degrees C; the maximum 94 degrees C, and minimum 40 degrees C. The colour of colony was yellow to bright orange. The G+C content of the DNA in strains has been found to be in the range 48.4-53.15 mol%.

[Culture of Streptomyces and purification of streptavidin]

For preparation and purification of Streptavidin, two synthetic mediums and a procedure for purifying Streptavidin were studied. We found that Streptomyces avidinii grew vigorously and showed typical colony characterization. At the sametime, these synthetic mediums were in favour of producing Streptavidin with a maximal production of 15.2 micrograms/ml by using DEAE 52 column for purification of Streptavidin. This purification procedure is very simple and easy, and could be widely used.

A novel variant of avian infectious bronchitis virus resulting from recombination among three different strains

An antigenic variant of avian infectious bronchitis virus (IBV), a coronavirus, was isolated and characterized. This strain, CU-T2, possesses a number of unusual features, which have not been previously observed in IBV. The S1 glycoprotein of CU-T2 carries virus-neutralizing and serotype-specific epitopes of two IBV serotypes, Arkansas (Ark) and Massachusetts (Mass). Sequence analysis revealed that the virus, originally an Ark serotype, has acquired the Mass-specific epitope by mutation(s). This provides evidence that point mutations may lead to generation of IBV antigenic variants in the field. It was further observed that two independent recombination events involving three different IBV strains had occurred in the S2 glycoprotein gene and N protein gene of CU-T2, indicating that genomic RNA recombination in IBV may occur in multiple genes in nature. It was especially significant that a sequence of Holland 52 (a vaccine strain) had replaced half of the N gene of CU-T2. This proves that recombination among vaccine strains is contributing to the generation of IBV variants in the field. Based on these observations it is predicted that every IBV field isolate could have unique genetic nature. Therefore, several recently reported diagnostic and serotyping methods of IBV which are based on dot-blot hybridization, restriction fragment length polymorphism (RFLP), and polymerase chain reaction (PCR), may not reveal the true antigenic and/or genetic nature of IBV isolates, and may in fact yield misleading information.

Involvement of muscarinic acetylcholine receptors in regulation of kitten visual cortex plasticity

Receptor autoradiographic methods specific for M3 and M1 muscarinic acetylcholine receptors were used to investigate the development and input-dependent laminar redistribution of these receptor populations during the critical period for kitten visual cortex plasticity. Analysis of the binding curves of [3H]4-diphenylacetyl-N-methyl-piperidine (4-DAMP) and [3H]pirenzepine (PZ) indicated that these two ligands bound heterogeneously to muscarinic acetylcholine receptors with different affinities. While [3H]4-DAMP showed a high affinity for M3 receptors and much lower affinities for M1 and M2 receptors, [3H]PZ displayed higher affinity for M1 receptors. By carefully choosing concentrations of labelled and unlabeled ligands, the patterns of laminar distribution for both receptor subtypes within visual cortex were obtained. Both receptors were most concentrated in cortical layer IV immediately after birth and during the most sensitive period of visual cortex plasticity. The binding density for both receptor subtypes thinned out progressively in this layer to concentrate in more superficial layers as plasticity waned with age. Moreover, interruption of visual or spontaneous input to visual cortex induced either by lesion or by tetrodotoxin infusion into lateral geniculate nucleus prevented the developmental redistribution of these receptors from layer IV to superficial layers, that is, the pattern of laminar distribution remained that of the age at which the lesion or tetrodotoxin infusion into the lateral geniculate nucleus was performed. The results indicate that the developmental expression of M3 and M1 muscarinic acetylcholine receptors in kitten visual cortex depends on cortical inputs.(ABSTRACT TRUNCATED AT 250 WORDS)

Development and regulation of beta adrenergic receptors in kitten visual cortex: an immunocytochemical and autoradiographic study

The developmental pattern and laminar distribution of beta 1 and beta 2 adrenergic receptor subtypes were studied in cat visual cortex with autoradiography using [125I]iodocyanopindolol as a ligand and also with immunocytochemistry using a monoclonal antibody directed against beta adrenergic receptors. In the primary visual cortex of adult cats, the laminar distributions of both beta 1 and beta 2 adrenergic receptors revealed by autoradiography were very similar, with concentrations in layers I, II, III and VI. In young kittens (postnatal days 1 and 10), fewer beta adrenergic receptors were present, and they were concentrated in the deep cortical layers (V-VI) and subcortical white matter. Between postnatal days 15 and 40, beta adrenergic receptors increased in density more quickly in the superficial layers than they did in the deep and middle cortical layers. By postnatal day 40, the adult pattern was achieved, with two bands of intense binding in the superficial and deep cortical layers and a lower density in layer IV. Immunocytochemical techniques applied to adult cat cortex showed that beta adrenergic receptor-like immunoreactivity was found in different populations of neurons and glial cells. The immunoreactive neural cells were most dense in layers II, III and VI. About 50% of these immunoreactive neural cells were glial cells, primarily astrocytes. Immunoreactive pyramidal cells were mostly located in layers III and V. In layer IV, many stellate cells were stained. Immunoreactive astrocytes in the subplate and white matter progressively increased in number during development until adulthood. The pattern of laminar distribution and the developmental process was not affected by interrupting noradrenergic innervation from locus coeruleus either before or after the critical period. However, when visual input was interrupted by lesions of the lateral geniculate nucleus in young kittens (postnatal day 10), the density of both beta adrenergic receptor subtypes decreased significantly in the deep cortical layers. Lateral geniculate nucleus lesions in adult cats resulted in a pronounced decrease in beta adrenergic receptor density in layer IV.

[Study on the induction of active immunity in human by injecting human anti-HBs antibodies]

One hundred and three health volunteers were injected with various doses of human anti-HBs (Ab1). The anti-idotypic antibodies (Ab2) and anti-antiidiotypic antibodies (Ab)3 in sera were tested at intervals of 30 days with ELISA. We found that the dynamic changes between Ab2 and Ab3 of immune sera were cyclical by way of their interaction and the Ag-specific Ab3 were the same as Ab1 in specificity. The results reconfirmed that exogenous human anti-HBs could induce active immunity by activation of idiotypic network and regulation in human body suggesting that injection of Ig into body could bring about not only passive immunity but also active immunity.

Comparison of the dynamics of an engineered insulin monomer and dimer by acid-quenched amide proton exchange. Non-local stabilization of interchain hydrogen bonds by dimerization

Dynamic differences between an engineered insulin monomer and dimer are investigated under physiological conditions by an adaptation of the method of acid-quenched amide proton exchange. Although exchange lifetimes of amide protons involved in intrachain hydrogen bonds are similar in the two analogs, dimerization specifically stabilizes two interchain hydrogen bonds (LeuB6-NH...O = C-CysA6 and CysA11-NH...O = C-GluB4) that are distant from the dimer interface. Such non-local stabilization demonstrates that fluctuations in the tertiary structure of the monomer are damped by dimerization. As the B6-A6 and A11-B4 hydrogen bonds are specific to the crystallographic T-state, their stabilization also indicates that the R-state (an allosteric feature of hexamer assembly) is not significantly populated in an isolated dimer. Our results are discussed in reference to recent hypotheses that crystal structures of insulin depict inactive conformers and that detachment of interchain contacts accompany receptor binding.

[Analysis of chemical constituent of essential oil in Lonicera japonnica Thunb. cultivated on the northern plain of Henan Province]

The chemical constituents of the essential oil in the dry flower and fresh flower of Lonicera japonica were analyzed by the GC-MS-DS technique and the superimposition of authentic samples. 27 and 30 monoterpenoids and sesquiterpenoids were identified from the essential oil of the dry flower and fresh flower respectively. The major constituents have been found to be linalool, geraniol, aromadendrene and eugenol etc.

[Expression of Pre-S1 and Pre-S2 in serum of patients with chronic type B hepatitis]

To study the expression of Pre-S1 and Pre-S2 and gene-encoded proteins of the hepatitic B virus, we investigated serum from 11 patients with chronic type B hepatitis in various phases, Pre-S1 and Pre-S2 proteins were detected by the monoclonal antibody-based enzyme method, the markers of active viral replication were determined with the presence of HBV-DNA and HBeAg. It was found that Pre-S1 was present in the serum of 3 patients with viral replication as well as of 6 out of 8 cases with no evidence of viral replication, Pre-S2 in the serum of 2 out of 3 patients with active viral replication as well as 4 out of 8 cases with no evidence of viral replication. The similar results also appeared in patient's serum in various phases. The data suggest that there is no correlation between the presence of the Pre-S1 or Pre-S2 proteins and active viral replication during the course of chronic type B hepatitis.

Effects of tensile stress on the R lines of Cr(3+) in a sapphire fiber

We have investigated the spectroscopic properties of a crystalline sapphire fiber unintentionally doped with Cr(3+). We find that tensile stress produces blue shifts of the R lines and changes in their radiative lifetimes and integrated intensities that can be correlated to stress-induced changes of the crystal-field parameters.

[Establishment and characteristics of a human synovial sarcoma cell line]

A human synovial sarcoma cell line (HSS-84), from a painful mass excised locally near the left sternoclavicular joint, was established and has been continuously propagated in vitro for more than one year through 54 passages till the end of 1985. Doubling time was 65 hr. The index of mitosis was 28.8%. The chromosome number for most of the cells was hypertriploid. The cells, stored in liquid nitrogen, had a good revival. Cytologically, some cells, showing elongated, spindle, stellate or spidery shape with prominent processes, were arranged in loose or bundled pattern, similar to sarcoma cells; some cells showed ovoid and polygonal in mosaic arrangement, similar to epithelioid cells. Both features indicated biphasic differentiation of the cells. By electron microscopy, the cells consisted of light and dark cells with microvilli and obvious abnormality. Histopathologically, the tumor, from which HSS-84 originated, was a biphasic differentiation synovial sarcoma. It was composed of malignant spindle interstitial cells and malignant epithelioid cells lining the clefts or spaces. The latter was similar to cultured cells by electron microscopy. HSS-84 was identical with the donor. HSS-84 establishment will be useful for research on diagnosis, therapy, origin and biphasic differentiation of the synovial sarcoma.

[Establishment of a human lung alveolar cancer cell strain and its characteristics]

A human lung alveolar cancer cell strain (HAC-84), isolated from lung adenocarcinoma cell line in Gejiu (GLC-82) by colony selecting method, has been continuously propagated in vitro for more than 2 years through 164 passages till May 1 st 1986. HAC has the typical malignant characteristics as GLC. There are plenty of phospholipid and osmiophilic multilamellar bodies in the cytoplasm of all cells and the membrane-like material in most of the nuclei, which differentiate HAC from GLC and the other types of lung cancers. The cytoplasmic inclusions are the same as those found in type II alveolar epithelial cells of the lung. So, HAC, originated from the type II alveolar cells, is identified as human lung alveolar cancer cell strain. It is significant in the research of the properties and origin of the alveolar cancer, the action and formation of the alveolar surfactants.