Isolation and characterization of a rice gene encoding a basic chitinase

Chitinase, which catalyzes the hydrolysis of the beta-1,4-N-acetyl-D-glucosamine linkages of the fungal cell wall polymer chitin, is involved in inducible defenses of plants. A basic chitinase genomic sequence was isolated from a rice (Oryza sativa L.) genomic library using a bean chitinase gene fragment as a probe. The complete nucleotide sequence of the rice chitinase RCH10 gene was determined, and shown to contain an open reading frame with no introns, encoding a polypeptide of 336 amino acids. This polypeptide consists of a 21 amino acid signal peptide, a hevein domain, and a chitinase catalytic domain. The RCH10 gene has 63% identity at the nucleotide level and 75% identity at the amino acid level with chitinase genes from dicotyledonous plants such as bean, potato, and tobacco. A gene fusion of trpE and the coding region of RCH10 expressed in Escherichia coli gave a product that reacted with antiserum to bean chitinase, confirming the identity of RCH10 as a rice chitinase gene. Primer extension analysis identified two transcription start sites 53 bp and 55 bp upstream from the translation initiation codon. The 5' flanking region contains TATA and CAAT boxes, and the 3' region contains an AATAA polyadenylation signal. Southern blot hybridization indicated that there is a family of chitinase genes in the rice genome. Northern blot analysis showed that the RCH10 chitinase gene is induced in suspension cultured cells by a fungal cell wall elicitor. Rice chitinase transcripts accumulate to a high level in roots, but only low levels are found in stem and leaf tissue.

Corticostatic peptides

In the last four years corticostatic (anti-ACTH) peptides have been isolated from human, rabbit, guinea pig and rat tissues. These peptides do not act via the cAMP cell signalling system but rather via the inhibition of the binding of ACTH to its receptor most probably through direct competition with the 14-18 sequence of ACTH for receptor binding. ACTH has specific high affinity receptors on adrenal cells but rabbit corticostatin I (CSI) has high capacity, low affinity receptors which are competed for by unlabelled excess CSI but not by excess ACTH. This indicates the presence of specific CSI adrenal cell receptors. The rabbit pituitary, hypothalamus, thalamus, adrenals, lungs and placenta contain sizeable amounts of immunoassayable CSI. Immunochemical localization of CSI indicates that it is present in the large macrophages and in neutrophils in rabbit lung, in macrophages and "supporting" endothelial cells in the spleen and in the adrenals in the cells of the zona reticularis. We have also isolated and identified new peptides which contain 12 cysteines from immune cells of humans, rats and a teleost, the carp. The functions of these peptides are now being determined. This large family of peptides may have many other, yet unidentified functions but at present we can only describe a small number of these.

Diagnostic contrast echocardiography in children with congenital heart disease

905 diagnostic contrast echocardiographic studies (DCE) were performed on 223 children. Carbon dioxide microbubble was used as contrast agent in various age groups, especially in newborns and infants because of its safety in application, stable contrast effect, and peripheral vein injection. Two-dimensional echocardiography (2-DCE), a useful tool in diagnosis of left to right shunt lesions reduced false negative diagnoses for ventricular septal defects and eliminated false positive diagnosis for atrial septal defects and patent ductus arteriosus. The accuracy of diagnosis in this series was 97%. The results of this series showed that 2-DCE is also valuable in the diagnosis of congenital heart disease with right to left shunts, and can be used to evaluate shunt levels and determine the obstructive sites on the right side of the heart.

[Adenosine deaminase inhibitor (EHNA) on ischemia-reperfusion injury in isolated perfused rat hearts]

The effects of Erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) on Langendorff perfused rat hearts subjected to ischemia-reperfusion injury were studied. Results showed that EHNA can inhibit the increase of cardiac resting tension during ischemia period and decreasing the incidence of ventricular fibrillation and its duration. The contraction amplitude, resting tension and heart rate could be recovered to preischemic level, and the coronary flow even greater than before. The authors thought that EHNA can block the breakdown of adenosine to inosine and hypothanxine, and, therefore, cut off the pathway and production of oxygen free radicals during ischemia-reperfusion injury.

[Short-term curative effect of cultured Cordyceps sinensis (Berk.) Sacc. Mycelia in chronic hepatitis B]

33 cases of chronic hepatitis B. patients treated with cultured Cordyceps sinensis mycelia have shown that the drug improves the liver function, promotes negative transfer HBsAg, and markedly helps to raise plasma albumin, resist high gamma globulin and to adjust body immunocompetence. It is therefore suggested that cultured Cordyceps sinensis mycelia may be used as a medicine for chronic hepatitis B. patients in adjusting protein metabolism and correcting inversion of albumin and globulin.

[Quantification of pulmonary to systemic flow ratio (Qp/Qs) in children with patent ductus arteriosus by echocardiography]

The assessment of left-right ductal shunting flow in 35 children with PDA by 2-DCE with 35 normal children as a control was shown in the study. A close relationship was demonstrated between the grade of the diastolic negative contrast at the distal ends of the pulmonary artery and Q p/Qs. The diastolic negative contrast effect of 2-DCE could be used as a new important index in the assessment of left-to-right ductal shunting flow. Four parameters which were closely correlated with Qp/Qs were selected from 8 parameters by the stepwise multilinear regression procedure. The 4 parameters were grade II DNCE, LVPWER, grade I DNCE, LADR. A regression equation which was capable of assessing Q p/Qs noninvasively in children with PDA was derived from the 4 parameters. The accuracy of calculation of Qp/Qs by the regression equation was 80%.

[Component analysis of the extracellular polysaccharide from Mortierella hepiali Chen et Lu sp. nov]

The extracellular polysaccharide from the filtrate of fungal fermentation of Mortierella hepiali, a fungus isolated from traditional Chinese crude drug Cordyceps sinesis, is made up of three sugar components, glucose, mannose and galactose, which are detected by paper and gas chromatography. Both molar ratio and contents of the polysaccharide are determined by the internal standard method.

Isolation and biological activity of corticostatic peptides (anti-ACTH)

Corticostatins (CS's) are a family of low molecular weight peptides, rich in arginine and cysteine with the ability to inhibit ACTH stimulated adrenocortical steroidogenesis. They show a high degree of specificity in that they do not inhibit the action of angiotensin II in the adrenal cortex. Four corticostatins have been isolated from rabbit lung extracts and peritoneal neutrophil extracts and one from human neutrophils. Among them corticostatin I, CSI, is the most potent with an I.D.50 of 25 nM. Corticostatin activity is different from other published inhibitory factors such as TGF-B and ANF, which inhibit basal and angiotensin II stimulated steroidogenesis. Other factors such as macrophage secreted products, and septic shock plasma factors which have not been fully characterized also have suppressive activity on ACTH induced adrenocortical steroidogenesis in vitro. It is not yet clear whether there is any relationship between corticostatins and these macrophage products and shock plasma factor. Corticostatins do not inhibit dbcAMP induced steroidogenesis, however they do inhibit the accumulation of cAMP in response to ACTH in rat adrenal cell suspensions. Binding studies show that CSI is a competitive inhibitor of ACTH, probably acting by blocking, the address recognition site of the receptor. There is wide variation in the potency of the corticostatins ranging from an ID50 of 100 ng/ml for CSI to a completely inactive analog, HP1. In this paper we will describe the purification of the corticostatins and some recent results obtained on their mechanism of action.

[Luteinized unruptured follicle syndrome]

In a group of 109 infertile women, 180 cycles were monitored with B type ultrasound, BBT and cervical scoring. The incidence of LUF in stimulated cycles was 31.8%, significantly higher than that in spontaneous cycles (10.1%). During the follicular phase, no difference was found between the LUFS and normal ovulatory cycles as to follicular growth curve, maximal diameter of dominant follicle and the cervical scores. Therefore prediction of the LUFS is difficult. 63.6% of the LUF patients had recurrences, and high incidence of abnormality (70.6%) in their non-LUF cycles. 7 of the 14 patients with LUFS were originally diagnosed as unexplained infertility. It suggests that LUFS is of particular importance in the group of women with unexplained infertility.

Chemical crosslinking of glycoproteins on the envelope of herpes simplex virus

A base-reversible, 13-A homo-bifunctional chemical crosslinking reagent, bis[2-(succinimidooxycarbonyloxy)ethyl]sulfone (BSOCOES), was tested for its ability to crosslink the herpes simplex virus type 1 glycoproteins associated with the envelope of purified virions. The crosslinked proteins were fractionated and analyzed by immunoblotting, immunoprecipitation, and two-dimensional polyacrylamide gel electrophoresis using monospecific antisera to detect the glycoproteins, gB and gC. Each of the glycoproteins exhibited distinct patterns of crosslinking. Monomers of gB were crosslinked and appeared as a high-molecular-weight complex. No apparent intermediates were observed between the gB monomer and the high-molecular-weight complex. Analysis of the components in the gB high-molecular-weight complex suggests that gB represents the major component and exists as a high-molecular-weight oligomer on viral envelopes under native conditions. In contrast, gC was cross-linked at a much lower efficiency and a number of components at intermediate molecular weights were detected. Initial studies on crosslinked products that were detectable with anti-gC antibody suggest that one of these products represents a gC dimer.