The longevity of actinosporean spores from oligochaetes of Lake Sasajewun, Algonquin Park, Ontario, and their reaction to fish mucus

The longevity of 7 forms of actinosporean spores and the reaction of 6 forms of actinosporeans to fish mucus were investigated. The maximum longevity of actinosporean spores kept at ambient laboratory temperatures was 14 days. Spore longevity ranged from 11 to 14 days among actinosporeans. The reaction of spores to fish mucus varied among the actinosporeans. Triactinomyxon F of Xiao and Desser, 1998 reacted only to the mucus of the common shiner Luxilus cornutus, and golden shiner Notemigonus crysoleucas, whereas the aurantiactinomyxon form of Xiao and Desser, 1998, and raabeia B of Xiao and Desser, 1998 reacted readily to mucus of all fish species tested. The differences in reaction to fish mucus among actinosporeans may indicate their different host range. These results indicate that actinosporean spores are short-lived and that actinosporeans respond to their hosts by chemodetection.

The protein information resource (PIR)

The Protein Information Resource (PIR) produces the largest, most comprehensive, annotated protein sequence database in the public domain, the PIR-International Protein Sequence Database, in collaboration with the Munich Information Center for Protein Sequences (MIPS) and the Japan International Protein Sequence Database (JIPID). The expanded PIR WWW site allows sequence similarity and text searching of the Protein Sequence Database and auxiliary databases. Several new web-based search engines combine searches of sequence similarity and database annotation to facilitate the analysis and functional identification of proteins. New capabilities for searching the PIR sequence databases include annotation-sorted search, domain search, combined global and domain search, and interactive text searches. The PIR-International databases and search tools are accessible on the PIR WWW site at http://pir.georgetown.edu and at the MIPS WWW site at http://www. mips.biochem.mpg.de. The PIR-International Protein Sequence Database and other files are also available by FTP.

[Preliminary study on relationship between antibody against heat stress protein 70 and hypertension]

OBJECTIVE

To preliminarily explore the relationship between main antibody against heat stress protein 70 (anti-HSP70) and hypertension.

METHODS

Serum anti-HSP70 was determined with Western blotting technique in hypertensive and normotensive groups. Logistic regression model was used to analyze the relationship between anti-HSP70 and hypertension.

RESULTS

It was found that level of antibody against the main heat shock protein 70 was significantly higher in patients with hypertension (based on criteria of 160/95 mm Hg, 1 mm Hg = 0.133 kPa) than in controls, after adjustment for the generally recognized risk factors for hypertension (such as age, sex, length of employment, body mass index, job, et al.). There still was stronger association between anti-HSP70 and hypertension (based on criteria of 140/90 mm Hg), but its strength of association was weaker than the former.

CONCLUSIONS

Anti-HSP70 may potentially serve as a serum biomarker to assess hypertension, or anti-HSP70 itself may be involved in the development of hypertension.

Detection and its implication of heat stress protein 27 and P21 in nasopharyngeal carcinoma

To study the expression of heat stress protein 27 (HSP27) and P21 in nasopharyngeal carcinoma (NPC) tissue, and to evaluate the significance of both HSP27 and P21 in the pathogenesis, development and prognosis of NPC. Indirect immunofluorescence method combined with SABC was applied. Our results showed that (1) the positive rates of HSP27 and P21 expressed in NPC tissue in 36 cases were 88.9% and 94.4%; (2) while in 10 hyperplastic nasopharyngitis tissues, the positive rate of HSP27 and P21 were both 5; (3) all the 5 normal tissues were negatively stained. It is obvious that a co-expressing tendency of HSP27 and P21 could be identified, and it was associated with the degree of malignancy and the clinical stage of NPC. It is concluded that the positive expression of HSP27 and P21 may have clinical significance in the evaluation of the occurring, development and prognosis of NPC, and in NPC treatment.

[Analysis for the titer of plasma antibody to heat stress protein 70 in workers exposed to benzene]

OBJECTIVE

To explore the titer of plasma antibody against heat stress protein 70 (HSP70) in workers exposed to benzene and its possible relationship to their health.

METHODS

Forty-two workers exposed to more than 40 mg/m(3) of benzene were selected as a high exposure group, 50 of workers exposed to less than 40 mg/m(3) as a low exposure group, and 42 unexposed as a control group. Their plasma antibody against HSP70 was determined with enzyme-linked immunosorbent assay (ELISA). Analysis was conducted to study the relationship between it and other factors.

RESULTS

Proportion of plasma positive antibody to HSP70 with a titer of 1:20 was significantly higher in high exposure group (26.2%) than that in controls (9.5%). Moreover, prevalence of adverse symptoms and positive signs, and level of lipid peroxide were all significantly higher in high exposure group with positive antibody to HSP70 than those with negative antibody.

CONCLUSION

It was concluded that the titer of plasma antibody to HSP70 had close relation with the health of workers exposed to benzene.

ProClass protein family database

ProClass is a protein family database that organizes non-redundant sequence entries into families defined collectively by PIR superfamilies and PROSITE patterns. By combining global similarities and functional motifs into a single classification scheme, ProClass helps to reveal domain and family relationships and classify multi-domain proteins. The database currently consists of >155 000 sequence entries retrieved from both PIR-International and SWISS-PROT databases. Approximately 92 000 or 60% of the ProClass entries are classified into approximately 6000 families, including a large number of new members detected by our GeneFIND family identification system. The ProClass motif collection contains approximately 72 000 motif sequences and >1300 multiple alignments for all PROSITE patterns, including >21 000 matches not listed in PROSITE and mostly detected from unique PIR sequences. To maximize family information retrieval, the database provides links to various protein family, domain, alignment and structural class databases. With its high classification rate and comprehensive family relationships, ProClass can be used to support full-scale genomic annotation. The database, now being implemented in an object-relational database management system, is available for online sequence search and record retrieval from our WWW server at http://pir.georgetown.edu/gfserver/proclass.html

Molecular characterization of myxozoan parasites from Lake Sasajewun, Algonquin Park, Ontario, by riboprinting

The small subunit-rRNA genes of 18 myxozoans from Lake Sasajewun, Algonquin Park were amplified and digested with restriction endonucleases for riboprinting analysis. Identical riboprints were not found between the myxosporeans and the actinosporeans. The distinct riboprinting patterns observed among these myxozoans indicate considerable genetic diversity within this group. Identical riboprints were found between Myxobolus pendula and Myxobolus pellicides, and between triactinomyxon 'C' and Triactinomyxon ignotum. Parsimony analysis of the riboprints demonstrated that neither the myxosporeans nor the actinosporeans formed a monophyletic group. Some species of Myxobolus are more closely related to forms of triactinomyxon, echinactinomyxon or raabeia than to other Myxobolus species. These results are consistent with the two-host life cycle hypothesis of myxozoans that myxosporeans and actinosporeans are alternating stages of the same organisms.

[A study on the roles of CD86 in antigen-induced eosinophil infiltration into airways and airway hyperresponsiveness]

OBJECTIVE

To explore the effect of CD86 on antigen-induced eosinophil infiltration into the airways and airway hyperresponsiveness in sensitized mice, and further elucidate the role of CD86 in the pathogenesis of bronchial asthma.

METHODS

Female BALB/c mice (n = 8 for each group) were sensitized and challenged with ovalbumin to induce airway eosinophilia and airway hyperresponsiveness. Airway responsiveness was espressed by the provocative concentration of acetylcholine causing 50% increase in respiratory resistance (PC50). Effect of anti-CD86 monoclonal antibody (mAb) on antigen-induced changes of eosinophil numbers in brochoalveolar lavage fluid (BALF) and airway reactivity was observed. CD86 expression on BALF cells was detected by flow cytometry and concentrations of interleukin-4 and interleukin-5 in homogenized supernatant of lung tissue were determined by ELISA.

RESULTS

In sensitized mice challenged with ovalbumin 20 minutes once a day for 6 days, the number of BALF eosinophils was (9.2 +/- 1.5) x 10(8)/L. However, no eosinophil could be found in the BALF from mice without ovalbumin sensitization and challenge. Also, ovalbumin treatment led to PC50 value decrease from (0.66 +/- 0.13) g/L to (0.17 +/- 0.07) g/L (P < 0.01). CD86 expression on BALF cells from ovalbumin sensitized- and challenged-mice (36.4 +/- 6.2) was much higher than that from control mice (12.3 +/- 3.6, P < 0.01). In mice treated with intravenous injection of anti-CD86 mAb before each challenge, BALF eosinophils decreased by 67% (P < 0.01), and PC50 value increased by 69% (P < 0.01). Our results showed that anti-CD86 mAb prevented antigen-induced airway eosinophilia and airway hyperresponsiveness accompanied by a decrement of levels of both interleukin-4 and interleukin-5 in lung tissue.

CONCLUSIONS

Anti-CD86 mAb is able to inhibit antigen-induced airway eosinophilia and to ameliorate airway hyperresponsiveness, possibly by inhibiting production of interleukin-4 and interleukin-5. These data suggested that the blockade of airway antigen-presenting cells' functions couid be of value in treatment of human asthma.

Effects of bead-bead interactions on the static and dynamical properties of model polymer solutions

The effects of segment-segment interactions on the static and dynamical properties of model polymer solutions are examined by Brownian dynamics simulations in the free-draining limit over a wide concentration range. A bead-and-spring model is used to describe the polymer chains at a coarse-grained level, in which segment-segment interactions are represented by a bead-bead pair potential with a Gaussian analytic form, beta u(ev)(r)=A exp(-r(2)/2 sigma(2)), where beta=1/k(B)T and A and sigma are characteristic energy and distance scales, respectively. The chain dimensions, self-diffusion coefficient, and viscosity of the systems are studied as functions of number density of beads of the system, rho, at given excluded-volume potential parameters, A and sigma. Our results show that in the limit of infinite dilution even for short chains (N approximately 10) there is statistically significant scaling behavior in the static and dynamical properties. For a system with given values of A and sigma the change in polymer coil size shows a realistic trend as the concentration of the system increases. In the dilute and concentrated regions the coil size decreases as a result of increasing interchain repulsions, while in the highly concentrated region the coil size increases again, showing a return to Rouse-like behavior because the intrapolymer and interpolymer segment-segment interactions become effectively indistinguishable for an arbitrary bead and to a large extent are "balanced out." In the limit of infinite dilution, the self-diffusion coefficient of the center of mass, D(cm), depends on N only and not on the potential parameter A, while in contrast the specific viscosity eta(sp) depends on both N and A. As the concentration increases D(cm) decreases and eta(sp) increases consistent with the behavior of real polymers. When the system becomes highly concentrated, however, both D(cm) and eta(sp) unrealistically return to the Rouse limit. This suggests that from the concentrated region upward in concentration, the entanglement or the topological constraints caused by the physical connectivity of the chains significantly influence their dynamical behavior. The mean-field segment-segment interactions or excluded-volume effects incorporated in the current coarse-grained bead-spring approach cannot capture this entanglement effect, and therefore give rise to unrealistic dynamical behavior in the concentrated regime.

ECSIT is an evolutionarily conserved intermediate in the Toll/IL-1 signal transduction pathway

Activation of NF-kappaB as a consequence of signaling through the Toll and IL-1 receptors is a major element of innate immune responses. We report the identification and characterization of a novel intermediate in these signaling pathways that bridges TRAF6 to MEKK-1. This adapter protein, which we have named ECSIT (evolutionarily conserved signaling intermediate in Toll pathways), is specific for the Toll/IL-1 pathways and is a regulator of MEKK-1 processing. Expression of wild-type ECSIT accelerates processing of MEKK-1, whereas a dominant-negative fragment of ECSIT blocks MEKK-1 processing and activation of NF-kappaB. These results indicate an important role for ECSIT in signaling to NF-kappaB and suggest that processing of MEKK-1 is required for its function in the Toll/IL-1 pathway.

[Cloning of the idiopathic azoospermia related genes with mRNA differential display method]

OBJECTIVE

Defect of some genes related to spermatogenesis may result in male infertility with azoospermia. This study aimed to clone some of the genes.

METHODS

Testis tissues from a patient with idiopathic azoospermia and from a normal fathered man were investigated with an improved mRNA differential display approach.

RESULTS

Significant difference was observed between the two tissues in gene expression. Five differential expressed sequence-tags (ESTs) were cloned and sequenced. Homology analysis with software advanced BLAST 2.0 showed that one EST shared 100% homology with cosmid L27h9, which located in Huntington's disease region on 4p16.3; the other 4 showed very low homology with sequences in GenBank.

CONCLUSION

Azoospermia has complex genetic heterogeneity. A gene located in Huntington's disease region on 4p16.3 is expressed in human testis during the spermatogenesis, and a loss of its function may associate with azoospermia.

Abnormalities of tumor suppressor genes P16 and P15 in primary maxillofacial squamous cell carcinomas

As members of the same gene family, tumor suppressor genes P16/CDKN2/INK4A and P15/INK4B have a high degree of structural and functional homology with both P16 and P15 proteins involved directly in the regulation of cell cycles. However, the status of P16 and P15 genes in primary maxillofacial squamous cell carcinomas (MSCC) has not been reported. Studies on abnormalities of these genes including homozygous deletion, methylation of the 5'CpG islands, and mutations were carried out in 65 primary MSCC with polymerase chain reaction (PCR), methylation-specific PCR (MSP), PCR-SSCP (single-strand conformation polymorphism), and DNA sequencing techniques. Of the 65 tumors, 22 (34%) were methylated; 7 (11%) displayed point mutations. The total frequency of alteration of the P16 gene was 43% (28/65). The methylation rate of P15 was 12% (8/65). No homozygous deletion was found in either the P16 gene or P15 gene. In all MSCC samples, almost half (49%) harbored an alteration of the P16 or P15 gene. The P16 gene was altered more frequently than P15, and therefore is inactivated by methylation or mutation in a significant proportion of MSCC. The P15 gene appeared to play a lesser role in tumorigenesis of these tumors.

A novel calmodulin-like protein gene in rice which has an unusual prolonged C-terminal sequence carrying a putative prenylation site

A rice cDNA encoding a novel calmodulin-like protein was identified. It has 38 additional amino acids at the C-terminus of a complete, typical calmodulin (CaM) sequence of 149 amino acids. The four C-terminal amino acid residues form a CAAL motif which could be a site for protein prenylation and may subsequently cause the protein to become membrane associated. RT-PCR analysis confirmed that such a combined protein gene truly exists in rice. Sequence analysis of its genomic counterpart showed that there is an intron located at junction of the normal CaM sequence and the 38 C-terminal amino acids. This introduces a potential stop codon for normal CaM if an alternative splicing mechanism is involved. Southern blot analysis of rice genomic DNA revealed that there is only one locus for this gene. The northern blot analysis showed that this gene is highly expressed in rice roots, shoots and flowers. The distribution of this protein demonstrates the functional importance of this novel CaM-like protein in rice.

Stimulation of osteoblast proliferation by C-terminal fragments of parathyroid hormone-related protein

Parathyroid hormone (PTH)-related protein (107-139) (PTHrP(107-139)) and PTHrP(107-111) have been reported to be potent inhibitors of isolated osteoclast activity, and inhibition of bone resorption by PTHrP(107-139) occurs in vivo. However, the actions of C-terminal PTHrP on osteoblast activity has not been studied much. The present study addresses this issue by examining the effect of PTHrP(107-139), PTHrP(107-119), PTHrP(120-139), and PTHrP(107-111) on the proliferation of fetal rat osteoblasts. Treatment with PTHrP(107-139) for 24 h caused a dose-dependent increase in cell number, [3H]thymidine and [3H]phenylalanine incorporation in cultured osteoblasts. The effect was apparent at concentrations of 10-10 M and greater and was sustained over time. PTHrP(107-119) and PTHrP(107-111) had effects on cell number, DNA, and protein synthesis which were comparable to those of PTHrP(107-139), whereas PTHrP(120-139) was without effect. Retroverted PTHrP(107-111) also stimulated all three activities but was only one tenth as potent as PTHrP(107-139). PTHrP(107-139) had no effect on osteoblast apoptosis. It is concluded that PTHrP(107-139) is not only an inhibitor of osteoclastic bone resorption but that it also stimulates osteoblast growth. This activity resides within the pentapeptide fragment PTHrP(107-111). These findings support a possible role for C-terminal fragments of PTHrP in the normal regulation of bone cell function and, possibly, bone mass.

Apoptotic cascade of neurons in the subcortical sensory relay nuclei following the neonatal infraorbital nerve transection

A terminal transferase-mediated dUTP nick end labeling (TUNEL) method was utilized for detection of neuronal death in the subcortical relay nuclei of the trigeminosensory system following the infraorbital nerve transection in newborn rats. At 18-24 h after injury, numerous TUNEL-positive profiles were found within the ventroposteromedial thalamic nucleus (VPM) contralateral to the injury, whereas the VPM on the ipsilateral side and of the age-matched normal control contained only a few profiles per section. Electron microscopy revealed that the TUNEL-positive profiles were apoptotic neurons. The ventral part of the ipsilateral brainstem sensory trigeminal nuclear complex (the nucleus principalis, and the subnuclei oralis and interpolaris) exhibited statistically significant 65-70% increase in number of apoptotic neurons compared to the contralateral side. Taken together with our previous study [T. Sugimoto, C. Xiao, H. Ichikawa, Neonatal primary neuronal death induced by capsaicin and axotomy involves an apoptotic mechanism, Brain Res. 807 (1998) 147-154], the present results demonstrated a cascade of apoptosis in the primary, secondary and tertiary order sensory neurons along the neuroaxis.

Electron microscopic demonstration of nick end-labeled DNA fragments during capsaicin-induced apoptosis of trigeminal primary neurons in neonatal rats

DNA fragmentation was induced in the trigeminal ganglion of newborn rats by subcutaneous capsaicin injection (50 mg/kg). Twenty-four hours later, numerous roundish profiles were intensely labeled by both a DNA polymerase I-mediated nick translation method and a terminal transferase-mediated tailing method. Direct electron microscopic examination of labeled profiles indicated that the labeled profiles were neurons at earlier stages of apoptosis. DNA fragmentation signal was first detected in the nucleoplasm and later spread to the cytoplasm. The cell finally disintegrated forming many small apoptotic bodies. DNA fragmentation signal in the apoptotic bodies was readily labeled by the tailing but not the translation method.

Postnatal changes in Bax-immunoreactivity and apoptosis of the rat trigeminal primary neurons

The developmental changes of Bax protein-like immunoreactivity (Bax-ir) and naturally occurring cell death were investigated in the trigeminal primary neurons of rats, in the first 2 postnatal weeks. At 1 day postpartum, the trigeminal primary neurons exhibited intense cytoplasmic Bax-ir. A densitometric analysis indicated >95% of cells exhibited an ir-density (the staining intensity as compared to the background level) higher than 1.5. By 2 weeks the ir-density significantly decreased with >95% lower than 1.5, that was similar to the adult level. A nick-end labeling method revealed DNA fragmentation in apoptotic trigeminal primary neurons in newborn rats. During the first 11 days the percentage of apoptotic cells was highly correlated to the postnatal days with a regression line y = -0.083x + 0.877 (r = 0.976). A possible role of Bax in neonatal rat primary neurons is discussed.

Neonatal primary neuronal death induced by capsaicin and axotomy involves an apoptotic mechanism

To clarify the mechanism of capsaicin-induced primary neuronal cell death, newborn and adult rats were given a subcutaneous injection of capsaicin (50 mg/kg). Neonatal capsaicin injection induced neuronal apoptosis in the trigeminal ganglion. Apoptotic neurons had peripheral stacks of long parallel endoplasmic reticulum that are characteristic to primary neurons of the B-type, and exhibited nucleoplasmic condensation, nuclear shrinkage and cytoplasmic fragmentation. Light microscopically, apoptotic neurons exhibited a sign of DNA fragmentation as revealed by a nick end labelling method. The proportion of apoptotic cells was quite low during the first 12 h after capsaicin injection (<1%), rapidly increase to 10.44% by 24 h, and decreased to 0.29% by 48 h. Normal and vehicle control levels of apoptosis were <1%. Nerve growth factor (NGF, 0.5 mg/kg) simultaneously administered with capsaicin reduced the incidence of apoptosis by about 35% at 24 h post-injection. Neonatal transection of the infraorbital nerve induced neuronal apoptosis similar to that produced by the neonatal capsaicin in the maxillary division of the trigeminal ganglion. Unlike capsaicin, however, the neurotomy-induced apoptosis was seen in neurons of both the A- and B-types. Neither the capsaicin injection nor the neurotomy induced apoptosis in adult rats, though mitochondrial swelling similar to that seen at 0.5 h after neonatal capsaicin was observed after capsaicin injection in adults. The results indicate that the capsaicin-induced and nerve injury-induced primary neuronal damages in newborn rats share a common final pathway, apoptosis.

Actinosporean stages of myxozoan parasites of oligochaetes from Lake Sasajewun, Algonquin Park, Ontario: new forms of triactinomyxon and raabeia

Eight forms of triactinomyxon and 6 forms of raabeia of oligochaetes from Lake Sasajewun, Algonquin Park are described. Of the 8 forms of triactinomyxon, 2 designated as triactinomyxon 'B' and 'E' were found in both Limnodrilus hoffmeisteri and Tubifex tubifex. Three additional forms, designated as triactinomyxon 'A,' 'C,' and 'D,' occurred in L. hoffmeisteri. One form infecting L. hoffmeisteri was identified as Triactinomyxon ignotum Stolc, 1899, and another infecting T. tubifex was tentatively identified as Triactinomyxon dubium Granata, 1924. One form infecting L. hoffmeisteri and Rhyacodrilus coccineus was designated as triactinomyxon 'F.' Of the 6 forms of raabeia, 4 designated as raabeia 'A,' 'B,' 'C,' and 'F' were found in L. hoffmeisteri, and 2 designated as raabeia 'D' and 'E' were recorded in T. tubifex. The sporoplasmic mass of each form of triactinomyxon usually moved posteriorly within the cavity of the spore axis and was released through its posterior end, whereas the sporoplasmic mass of each form of raabeia was released through the anterior end of the epispore. An increase in the number of germ cells was observed in the floating spore stage of triactinomyxon 'B,' 'D,' 'E,' and raabeia 'B.'

Actinosporean stages of myxozoan parasites of oligochaetes from Lake Sasajewun, Algonquin Park, Ontario: new forms of echinactinomyxon, neoactinomyxum, aurantiactinomyxon, guyenotia, synactinomyxon and antonactinomyxon

Six forms (5 of which are new) of echinactinomyxon and 5 new forms of the collective groups neoactinomyxum, aurantiactinomyxon, guyenotia, synactinomyxon, and antonactinomyxon of oligochaetes in Lake Sasajewun, Algonquin Park are described. Five forms of echinactinomyxon designated as echinactinomyxon 'A,' 'B,' 'C,' 'D,' and 'E,' a form of neoactinomyxum, and a form of aurantiactinomyxon were found in Limnodrilus hoffmeisteri. Echinactinomyxon radiatum, a form of synactinomyxon, and a form of antonactinomyxon were recorded from Tubifex tubifex. A form of guyenotia was found in Lumbriculus variegatus. The sporoplasmic mass of these actinosporeans was released through the anterior end of the epispore. An increase in the number of germ cells was observed in the floating spore stage of all forms except echinactinomyxon 'C' and the form of antonactinomyxon.

The oligochaetes and their actinosporean parasites in Lake Sasajewun, Algonquin Park, Ontario

There is little ecological information on actinosporean parasites and their oligochaete hosts. Between 1995 and 1997, about 14,100 oligochaetes belonging to 19 species were collected from Lake Sasajewun. The oligochaete fauna consisted of 5 tubificid, 10 naidid, 3 enchytraeid, and 1 lumbriculid species. The most widely distributed species in the lake were Limnodrilus hoffmeisteri, Dero nivea, and Stylaria lacustris, with L. hoffmeisteri being the most prevalent. The diversity and abundance of worms decreased with increased water depth. Four species, L. hoffmeisteri, Tubifex tubifex, Rhyacodrilus coccineus, and Lumbriculus variegatus, harbored actinosporean parasites and were distributed along shallow areas of the lake shore where the sediment was comprised mainly of clay-mud, with the shoregrass, Littorella americana. The actinosporean parasites of the oligochaetes belong to 25 forms of 8 collective groups. Triactinomyxon 'F' was the most prevalent form, whereas triactinomyxon, raabeia, and echinactinomyxon were the most speciose groups. The overall prevalence of actinosporeans was about 1%. Waterborne spores of different actinosporean forms showed distinct temporal patterns. Spores of triactinomyxon 'F' occurred throughout the sampling season, whereas spores of other forms occurred only at certain times. The presence of waterborne spores peaked from late June to August when water temperatures ranged from 18 to 24 C and coincided with the feeding and growing season of larval fish.

[The influence of several factors on automated DNA sequencing]

OBJECTIVE

To investigate the influence of several factors on isothermal automated DNA sequencing.

METHODS

The effects of DNA purity and DNA concentration, as well as the quality of water used during sequencing on automated DNA sequencing results were retrospectively analyzed.

RESULTS

When the DNA was not pure enough, the nucleotide curve showed lower ratio of signal to noise, or compression would occur, leading to difficulty in correctly judging the nucleotides; the readable length of nucleotides was shorter when low concentration of DNA was used; when the quality of water used in sequencing reaction and polyacrylamide gel solution was not high enough, the peaks of nucleotides became wider and flatter, or double peaks would occur, resulting in unreadable sequences.

CONCLUSION

DNA purity and concentration as well as quality of water used in sequencing reaction and polyacrylamide gel solution had apparent influence on isothermal automated DNA sequencing. This suggests that high purity of DNA and high quality of water should be used in isothermal automated DNA sequencing; if longer DNA sequence needs to be obtained, DNA concentration should not be too low.

[Shadow bands in PCR amplification of trinucleotide repeats and their elimination]

OBJECTIVE

To explore a method for eliminating the shadow bands in PCR amplification of trinucleotide repeats.

METHODS

CTG trinucleotide repeat sequence in the 3'-untranslated region of the human myotonin protein kinase gene was used as templates DNA in PCR amplification, and the effects of Taq DNA polymerase alone and its mixture with Pwo DNA polymerase on occurrence of the shadow bands' were compared. The PCR products containing(CTG)5, both from Taq DNA polymerase and from Taq+Pwo polymerase amplification, were cloned into pBluecript KS and sequenced on ALF express TM DNA sequencer respectively.

RESULTS

The PCR of DNA sequence containing CTG repeats frequently produced a main band (usually darker) and a shadow band (lighter) that differed from the main band by 3 base pairs when Taq DNA polymerase was used alone. However, when the mixture of Taq DNA polymerase and Pwo DNA polymerase was used, the shadow bands usually disappeared. In the 4 clones containing PCR products amplificated by Taq DNA polymerase, one clone contained only 4 CTG repeats. However, this kind of decrease of repeat copy was not observed in the 5 clones containing PCR products amplified by using mixture of Taq+Pwo DNA polymerase.

CONCLUSION

The results of this experiment demonstrate that shadow bands occur during the PCR. Pwo DNA polymerase in known to possess not only DNA polymerase activity, but also 3'-5' exonuclease activity, or proofreading ability. The mixture of Taq DNA polymerase and Pwo DNA polymerase has higher processivity than Taq DNA polymerase itself. This explain the effect on eliminating or reducing the occurrence of shadow bands in polymerase chain reaction.

c-fos induction in the subnucleus oralis following trigeminal nerve stimulation

Neurons with c-Fos protein-like immunoreactivity (fos-neurons) were examined in the rostral parts of the brainstem sensory trigeminal nuclear complex following intense electrical stimulation of the trigeminal nerves and noxious mechanical stimulation of the trigeminal receptive fields. Stimulation of all the examined nerves and receptive fields induced some fos-neurons at the medial edge of the subnucleus interpolaris but not in the principal sensory trigeminal nucleus. Stimulation of the primary neurons innervating the intraoral structures but not facial skin induced fos-neurons in the ipsilateral subnucleus oralis. These oralis fos-neurons were located in the dorsomedial nucleus that contained calcitonin gene-related peptide-like immunoreactivity. The oralis fos-neurons are considered to be involved in the processing of intraoral nociceptive signals.

[Comparative study on efficacy of regimens including streptomycin or ethambutol]

OBJECTIVE

To evaluate the advantages and disadvantages of regimens of 2E3H3R3Z3/4H3R3(EMB regimen) and 2S3H3R3Z3/4H3R3(SM regimen) in tuberculosis control program.

METHOD

Retrospective, cross-sectional and prospective studies were carried out in Shijiazhuang city, Hebei province from January 1994 to June 1996.

RESULT

There was no significant difference between the two regimens in efficacy, relapse rate and full course supervision. The EMB regimen was found more applicable than the SM regimen, and the SM regimen caused more side effects than the EMB regimen. Streptomycin skin test had a 4.5% positive rate, and using SM costs 84% more than using EMB. One of the drawbacks found in the SM regimen was that only in 42.9% of the rural sanitation units the disinfection standard could be fulfilled, and the patients preferred the EMB regimen to the SM regimen.

CONCLUSION

The EMB regimen is more applicable than the SM regimen in the tuberculosis control program.

Cloning and mapping of bovine ZFX gene to the long arm of the X-chromosome (Xq34) and homologous mapping of ZFY gene to the distal region of the short arm of the bovine (Yp13), ovine (Yp12-p13), and caprine (Yp12-p13) Y chromosome

A part of mouse Zfy-2 sequence was synthesized and used to screen a genomic library of the spinous country-rat (Tokudaia osimensis spp., 2n = 45). An isolated clone had the C-terminal region of Zfy, which consisted of 1190 bp, encoded 336 amino acid residues, and harbored 11 out of 13 zinc finger motifs. With this as a probe, a bovine testis cDNA library was screened. Two ZFX clones were isolated and their sequences combined. The short sequence, lacking part of the 5' upstream region, was amplified by PCR or RT-PCR, cloned, and sequenced. A full-length ZFX was constructed by combining these three sequences. The bovine ZFX consisted of 5328 bp and encoded 800 amino acid residues, which contained 13 zinc finger motifs. ZFX was used as a probe for fluorescence in situ hybridization and was mapped to Xq34, different from its previously reported site at Xq21-q231. A SINE (short interspersed nuclear element) sequence consisting of 188 bp was found close to the end of the 3'-untranslated region of ZFX. The SINE sequence hybridized to all bovine chromosomes. ZFY is highly homologous with ZFX and, as a result, ZFY could be mapped simultaneously. ZFY was mapped to the distal region of the short arm of the Y Chromosome (Chr) (Yp13), contradicting the previously reported position Yq1. Ovine and caprine ZFY were also mapped with bovine ZFX. Both were mapped to the distal region of the short arm of the Y Chr (Yp12-p13). Ovine ZFX was mapped to a region close to the centromere of the X Chr (Xq13).

[Efficacy of unfixed continuation phase short-course chemotherapy]

OBJECTIVE

To evaluate the efficacy of the short-course chemotherapy shorter than six months.

METHOD

The 2SHRZ/xHR regimen was used in 290 smear positive new untreated tuberculosis patients. The duration of continuation phase was not fixed, just in accordance with the speed of sputum negative conversion. The treatment was continued until sputum negative conversion mantained for three consecutive months.

RESULT

Two hundred eighty-three out of 290 patients were cured. The sputum negative conversion rate at the end of the sixth month was 98.3%. The duration of treatment was 4.7 months on the average. The rate of two-year follow-up was 94.3%, and the rate of bacteriological relapse during two-year follow-up was 1.9%.

CONCLUSION

The results showed that the length of the six-month short-course chemotherapy could be shortened, and its recent and long-term efficacy was found satisfactory.

Trigeminal primary projection to the rat brain stem sensory trigeminal nuclear complex and surrounding structures revealed by anterograde transport of cholera toxin B subunit-conjugated and Bandeiraea simplicifolia isolectin B4-conjugated horseradish peroxidase

Trigeminal primary afferent neurons were labeled by injecting the rat trigeminal ganglion with either wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP), cholera toxin B subunit (B)-HRP or Bandeiraea simplicifolia isolectin B4 (IB4)-HRP. B-HRP stained medium to large cells (> 600 microm2), while IB4-HRP mostly small cells (< 400 microm2). WGA-HRP labeled trigeminal ganglion neurons of all sizes. Cell bodies in the mesencephalic trigeminal tract nucleus were labeled with WGA-HRP and B-HRP but not IB4-HRP. B-HRP revealed dense projection to the entire brain stem sensory trigeminal nuclear complex (BSTC) except for lamina II of the medullary dorsal horn (MDH). Some contralateral projection was also seen in the caudal part of MDH. Non-trigeminal nuclei receiving B-HRP-labeled terminals included the paratrigeminal nucleus (paraV), solitary tract nucleus, supratrigeminal nucleus, Probst's nucleus and median accessory nucleus. Following IB4-HRP application, terminal label was found in more restricted regions within the BSTC. Modest terminal label was seen in the dorsal part of principal sensory nucleus and at the medial edge of subnucleus interpolaris, while relatively dense terminal fields were seen in the dorsal half of subnucleus oralis. The MDH laminae I and II contained dense terminal label. Non-trigeminal nuclei were almost devoid of the IB4-HRP-labeled terminals excepting the paraV that contained dense terminal label. The terminal areas revealed with WGA-HRP coincided with B-HRP-labeled and IB4-HRP-labeled areas combined.

Tight links between adenine and guanine nucleotide pools in mouse pancreatic islets: a study with mycophenolic acid

Glucose metabolism in pancreatic B-cells leads to an increase in the ATP/ADP ratio that might participate in the regulation of insulin secretion. Good correlations have also been observed between guanine nucleotide levels in isolated pancreatic islets and insulin secretion. To assess whether guanine nucleotides have a specific role in stimulus-secretion coupling, their concentration should be modified selectively. This was attempted by culturing mouse islets overnight in the presence of mycophenolic acid (MPA), an inhibitor of GMP synthesis at the level of IMP dehydrogenase. The drug (25-50 microg/ml) did not affect the insulin content but decreased the GTP content of the islets and inhibited insulin secretion during subsequent incubation in the presence of 15 mM glucose. However, MPA also decreased the ATP/ADP ratio in the islets. The addition of guanine to the culture medium (to stimulate the salvage pathway of GTP synthesis) restored normal GTP levels, corrected the ATP/ADP ratio and partly prevented the inhibition of insulin release. In contrast, attempts to stimulate ATP synthesis specifically (by provision of adenine or adenosine) failed to reverse any of the effects of MPA. It is concluded that guanine and adenine nucleotide pools are tightly linked and cannot be specifically affected by MPA in pancreatic islet cells, probably because of the activity of nucleoside diphosphate kinase and because of the role of GTP in several reactions leading to adenine nucleotide generation. Contrary to previous claims, MPA is not an adequate tool for evaluating a specific role of guanine nucleotides in the control of insulin secretion.

[A study on the possible mechanism for the second control site of insulin secretion in islets]

Glucose stimulation of insulin release involves closure of ATP-sensitive K+ channels (K(+)-ATP channels) in beta cells. However, by using diazoxide to open K(+)-ATP channels, it has been reported that another mechanism exists, by which glucose can control insulin release independently from changes in K(+)-ATP channel activity. These data suggested that there is a second control site in islets when insulin is secreted. To probe the possible existence of this site, mouse islets were used to investigate the energy state of islets in insulin secretion when the activity of K(+)-ATP channels was eliminated by diazoxide. In the present study, isolated islets were cultured in PRMI 1640 medium for 18 hours. The islets were then divided into 6 groups randomly, with 10 islets per group, placed in 1 ml KREBS medium containing 30 mmol/L K(+) and 250 mmol/L diazoxide with 0, 3, 6, 10, 15, 20 mmol/L glucose respectively and incubated in 37 degrees C water for 60 minutes. A portion of the supernatant was withdrawn at the end of the incubation for insulin assay, the islets were treated with trichloracetic acid and diethyl ether for the measurements of ATP, ADP, GTP and UTP. The above findings demonstrated that insulin secretion increases with the rise of glucose concentration. In the same time, the level of ATP increaseded and the level of ADP decreased gradully. The ratio of ATP/ADP in islets correlated with the insulin secretion very well. The level of GTP and UTP also increased with the rise of glucose concentration. It is suggested that glucose can control insulin secretion independently from its action of K(+)-ATP channels and the existence of a second control site as an another mechanism for insulin release. The ratio of ATP/ADP is an important factor in this mechanism; GTP and UTP also participated in the control of insulin secretion.

Infiltration of eosinophils into the asthmatic airways caused by interleukin 5

Interleukin (IL)-5 is thought to play an important role in asthmatic bronchial mucosal inflammation and is a potential therapeutic target. To investigate the effect of IL-5 on the infiltration of eosinophils in airway in vivo, we compared eosinophil counts and their activation status in airways without and after the topical instillation of recombinant human IL-5. Eight subjects with mild atopic asthma underwent initial bronchoscopy during which control bronchoalveolar lavage (BAL) fluid as well as bronchial mucosa were obtained, and at the same time, normal saline and IL-5 were administered to two sublobar segments separately. The second bronchoscopy were carried out and samples from challenged sites were taken 24 h later. It was found that the total eosinophils (BMK-13+ cells) and the activated eosinophils (EG2+ cells) in bronchial mucosa, the eosinophil numbers in BAL fluid, as well as eosinophil cationic protein (ECP) in BAL fluid from saline-challenged segments were not different from those in unchallenged segments. However, a significant eosinophilia was observed in bronchial mucosa and BAL fluid from IL-5-challenged sites. Eosinophil activation, as assessed by secretion of ECP, was also increased significantly in bronchial mucosa and BAL fluid. The results strongly suggested that IL-5 is capable of inducing eosinophil infiltration into the asthmatic airways, as well as the activation of infiltrating eosinophils.

Central projection of calcitonin gene-related peptide (CGRP)- and substance P (SP)-immunoreactive trigeminal primary neurons in the rat

Substance P (SP) is implicated in transmission of primary afferent nociceptive signals. In primary neurons, SP is colocalized with calcitonin gene-related peptide (CGRP), which is another neuropeptide marker for small to medium primary neurons. CGRP coreleased with SP augments the postsynaptic effect of SP and thereby modulates the nociceptive transmission. This study demonstrates the distribution of CGRP-like immunoreactivity (-ir) and SP-ir in the lower brainstem of normal rats and after trigeminal rhizotomy or tractotomy at the level of subnucleus interpolaris (Vi). By comparing the results obtained from normal and deafferented rats, we analyzed the central projection of trigeminal primary nociceptors. The CGRP-immunoreactive (-ir) trigeminal primaries projected to the entire rostrocaudal extent of the spinal trigeminal nucleus, the principal nucleus (PrV), the paratrigeminal nucleus (paraV), and the lateral subnucleus of solitary tract nucleus (STN) on the ipsilateral side. The trigeminal primaries projecting to the spinal trigeminal nucleus, paraV and STN also contained SP-ir. The ipsilateral trigeminal primaries were the exclusive source of CGRP-ir terminals in the PrV, the Vi and the dorsomedial nucleus within the subnucleus oralis (Vo). The medullary dorsal horn (MDH) and the lateral edge of Vo received convergent CGRP-ir projection from the ipsilateral trigeminal primaries and other neurons. The glossopharyngeal and vagal primaries are candidates for the source of CGRP-ir projection to the Vo and the MDH, while the dorsal root axons supply the MDH with CGRP-ir terminals. In addition, contralateral primary neurons crossing the midline appear to contain CGRP and to terminate in the MDH.

Exaggerated C-fiber activation prevents peripheral nerve injury-induced hyperinducibility of c-Fos in partially deafferented spinal dorsal horn

Dorsal horn neurons chronically deafferented by peripheral nerve injuries acquire hypersensitivity to noxious input from outside the original receptive field. This study examines the effect of electrical nerve stimulation at the time of injury on such injury-induced hypersensitivity. The medial 3/8 of the dorsal horn laminae I/II around the junction of 4th and 5th lumbar segments (the tibial territory) was deafferented by transection of the ipsilateral tibial nerve in rats. At 2 days or 3 weeks postinjury, the hindpaw was injected with formalin to induce c-fos. At 2 days, neurons with induced c-Fos protein-like immunoreactivity (fos-neurons) were largely confined in the lateral 5/8 of laminae I/II (the peroneal and hip, thus P and H territory). At 3 weeks, fos-neurons significantly increased in the deafferented tibial territory. A similar increase was also noted in the P and H territory. Thus the dorsal horn neurons exhibited c-fos hyperinducibility, an indication of hypersensitivity. Electrical stimulation with a train of 150 shocks (10 V, 2 ms) of the proximal nerve stump immediately after transection prevented the c-fos hyperinducibility. The effect was greater with the stimulation frequency of 0.5 Hz than 0.1 Hz or 10 Hz. The stimulation had no effect on the c-fos inducibility at 2 days postinjury.

Parvalbumin-immunoreactive nerve endings in the periodontal ligaments of rat teeth

Parvalbumin-immunoreactive nerve fibres were most abundant in the lingual periodontal ligaments of incisor teeth. In the part of the ligament adjacent to the alveolar bone, thick and smooth parvalbumin-immunoreactive nerve fibres left main nerve bundles and passed towards the part of the ligament adjacent to the tooth. In the ligament, halfway between the bone and tooth surfaces, these nerve fibres repeatedly branched and extended one to four twigs to produce bush-like endings. Parvalbumin-immunoreactive fibres and terminals were infrequent in the periodontal ligaments of the molar teeth. It is possible that parvalbumin-immunoreactive endings are periodontal mechanoreceptors, but at present it is difficult to account for the different representations around rat molar and incisor teeth.

Bax protein-like immunoreactivity in primary sensory and hypothalamic neurons of adult rats

Bax protein-like immunoreactivity (Bax-ir) was examined in the perfusion-fixed, cryosectioned rat nervous system. In the central nervous system, hypothalamic neurons were the only neurons that exhibited Bax-ir in the cell body. Their axons traveled toward the median eminence, suggesting that the Bax-like immunoreactive (Bax-ir) hypothalamic neurons included neurosecretory ones. Bax-ir axons were observed in the solitary tract nucleus, and spinal and medullary dorsal horns. They appear to have been derived from Bax-ir primary sensory neurons in the viscerosensory nodose ganglion and somatosensory dorsal root and trigeminal ganglia. In the somatosensory ganglia, smaller cells exhibited stronger Bax-ir. Accordingly, the ir axons in the dorsal horn were most concentrated in lamina II.

Two-dimensional crystallization of rabbit C-reactive protein on lipid monolayers

Two-dimensional (2D) crystals of rabbit C-reactive protein (CRP) have been obtained by protein binding on lipid monolayers at the air/water interface. Two different types of crystalline arrays of CRP were obtained, by specific binding and non-specific adsorption to the lipids. Electron crystallographic analysis of the negatively stained specimens showed that the unit cell parameters of the CRP 2D crystals formed by specific binding were a=81 angstroms, b=78 angstroms, gamma=118.35 degrees, and those formed by nonspecific adsorption were a=74 angstroms, b=67 angstroms, gamma=95.5 degrees, both with the layer group p1. Projection maps were obtained at a resolution of 26 angstroms and 22 angstroms respectively. They showed that only the monomers of the CRP were packed in the 2D arrays and the orientations of the monomers on the lipid monolayers were different in the two types of crystals. By comparing the two projection maps, a preliminary shape of the CRP monomer has been derived. A model of the pentameric structure of the oligomeric CRP has been proposed.

Study on serum-free media for genetically engineered CHO cells producing prourokinase

Based on the initial optimization of DMEM:F12(1:1), two kinds of serum-free media, 11G-SG-SFM and 11G-SE-SFM, were formulated by using orthogonal experiments for the growth of genetically engineered CHO cell line 11G and the production of recombinant prourokinase (pro-UK) in a suspension culture, respectively. Growth of 11G cells in 11G-SG-SFM was comparable with that observed in DMEM:F12 + 5% NBS and CHO-S-SFM. 11G cells grew slowly in 11G-SE-SFM, but secreted a relatively high level of pro-UK. The pro-UK productivity of 11G cells in 11G cells in 11G-SE-SFM reached 800 to 1,000 IU/10(6). d-1 and was about 80% and 20% higher than in DMEM:F12 + 5% NBS and CHO-S-SFM, respectively.

Specific binding of avidin to biotin containing lipid lamella surfaces studied with monolayers and liposomes

The interaction of avidin (from egg white) with phospholipid (monolayer and bilayer) model membranes containing biotin-conjugated phospholipids has been studied. In the first part, using surface sensitive techniques (ellipsometry and surface plasmon resonance) we demonstrated that the nonspecific adsorption of avidin to phospholipid lamella could be abolished by adding an amount of Ca2+, Mg2+ or Ba2+ that led to an electrostatic interaction. The specific binding of avidin to lipid mixtures containing biotin-conjugated phospholipids was obviously composition dependent. The ratio 1:12 of a B-DPPE/DPPE mixture was found to be the optimum molar ratio. When we compared the results from the surface sensitive techniques with those from the electron micrographs of a two dimensional crystal of avidin (obtained in our laboratory), the optimum ratio was found to be determined by the effect of lateral steric hindrance. In the second part, we observed the pattern of the layers of fluorescently labeled phospholipid and adsorbed proteins with a home-made micro fluorescence film balance. The fluorescence images showed that avidin was preferentially bound to the receptors that were in the fluid domains. Further, with a sensitive fluorescence assay method, the effect of the phase behavior of liposomes on the specific binding of avidin was measured. This showed that avidin interacted with biotinlipid more weakly in the gel state liposome than in the liquid state liposome. The major conclusion was that the binding of avidin to a membrane bound model receptor was significantly restricted by two factors: one was the lateral steric hindrance and the other was the fluidity of the model membrane.

Distribution of red cell blood group systems in Achang and De'ang ethnic groups in China

A survey on the distribution of red cell group systems, including ABO, MNSs, Rhesus and P, was carried out in the Achang and De'ang ethnic groups in Yunnan Province, South-West China. The Achangs are characterized by the highest frequency of IA in China, while the De'angs show a high frequency of IO and CDe. The distribution of these blood group systems in Achang and De'ang exhibits the same characteristics observed in other ethnic groups of South China.

High density cultivation of a recombinant CD-1 cell line producing prourokinase using a Biosilon microcarrier culture system

CD-1, a genetically-engineered CHO cell line, was cultivated with a Biosilon microcarrier culture system. We successfully cultivated CD-1 cells to a very high density (over 1 x 10(7) cells/ml). Prourokinase was stably secreted at about 180 IU/10(6) cells/24 h. Experiments showed that CD-1 cells growing on Biosilon microcarriers were able to spontaneously release from the microcarriers, then reattach and proliferate on fresh microcarriers. This makes it very easy to scale up production. The microcarriers could be reused several times without affecting adhesion, proliferation and prourokinase secretion. With CM-PECC membrane radial flow chromatography and MPG chromatography, the prourokinase in conditioned medium could be purified to a specific activity of 1 x 10(5) IU/mg of protein. The purification factor was about 600 fold, and approximately 90% of the biological activity was recovered.

High density cultivation of genetically-engineered CHO cell lines with microcarrier culture systems

Genetically-engineered CHO cell lines, r beta-13 and CLF-8B2, were cultivated with the MC-1 microcarrier culture system. The cell density could be enhanced by increasing the concentration of microcarrier. At a microcarrier concentration of 10 mg/ml, the cell density could reach 4 to 5 x 10(6) cells/ml. It was shown that these cell lines would spontaneously release from the microcarrier to attach to and proliferate on fresh microcarriers. We were thus able to scale up cultivation using a simple method, i.e. by adding fresh microcarriers and medium directly into the culture system to about 2, 4 or 8 times the original volume. Using a perfusion culture system, we have successfully cultivated CLF-8B2 cells in a 2 L bioreactor for several weeks at medium perfusion rates of 0.5 to 3 working volumes. Prourokinase was stably secreted.

[New species of Haloarcula]

Three strains of pleomorphic halobacteria (A5, B2 and B-B2) were isolated from salt lakes of Xinjiang, China. Based on the Bergey's Manual of Systematic Bacteriology, Volume 3 (1989) and the analytical results of polar lipids, the three strains could be included in the genus Haloarcula. But since they differ from normally accepted two species of this genus in cell shape and physiological and biochemical features, it is suggested that the three strains belong to a new species, called Haloarcu la aidinensis sp. nov.

Pilot production of high-titer interferon and virus with a microcarrier suspension culture system

We have successfully cultured four cell lines--L929, BHK-13, BHK-21 and CHO-K1 using an MC-1 type microcarrier made in our academy. With the microcarrier in a concentration of 5 mg/ml, the cell density was about 30 x 10(4) cells/ml; after 3 days in suspension culture, the cells could proliferate to 1 x 10(6) cells/ml. At this time, when L929 cells were primed with 25 IU/ml MuIFN for 14-24 h and then superinduced with NDV, cycloheximide (20 micrograms/ml) and actinomycin D (2 micrograms/ml), the titer of IFN reached approximately 10(5) IU/ml (10(5) IU/mg of protein, expressed in specific activity). When VSV was inoculated into the other three cell line cultures, the viral titer reached 6 Log TCID50/ml or much higher. The yield with the CHO-K1 cell line was the highest, reaching titers of 7-8 Log TCID50/ml. These titers were similar to those seen in stationary culture. With trypsin-citrate solution and a more rapid stirring speed, the cells could be satisfactorily released from the microcarriers and reattached on fresh ones. These experiments show that the microcarrier suspension culture system is suitable for producing large scale, high-titer, low-cost vaccines and IFNs, both natural and recombinant, using genetically-engineered CHO cell lines.

[The characterization of mutant No. 68 from midecamycin producing strain S. mycarofaciens 1748]

A stable mutant No. 68 was obtained by treatment of S. mycarofaciens 1748 spores at high temperature. The electromicroscopic examination has shown that the mutant No. 68 and parent strain 1748 both have the spore chains of the spiratype. The spores of both strain are cylindrical in shape. The only difference is that the spores of the mutant No. 68 are of smooth surface, but the 1748 are of thorny. The physiological characteristics of both strains are also very similar with slight differences in utilization of few carbon sources and in cultural characters in few medium. Feeding experiment has shown that the mutant No. 68 was blocked in the formation of the macrolide lactone in the midecamycin biosynthetic pathway. This suggested that the mutant No. 68 might be a polyketide synthase genes deficient mutant. The ability of the mutant No. 68 to convert spiramycin into 4"-propionylspiramycin indicated that the mutant No. 68 contained the midecamycin 4"-propionyltransferase and could be used for microbial bioconversion of spiramycin into 4"-propionylspiramycin.