Isozyme Profiles Research Articles

Extracellular Mannose-6-phosphatase of Phanerochaete chrysosporium: A Lignin Peroxidase-Modifying Enzyme

The lignin peroxidase (LIP) isozyme profile of the white-rot fungus Phanerochaete chrysosporium changes markedly with culture age. This change occurs extracellularly and results from enzymatic dephosphorylation of LIP isozymes. In this study, a novel mannose 6-phosphatase (M6Pase) from extracellular culture fluid filtrate of P. chrysosporium, shown to be responsible for the extracellular postranslational modification of LIP, was purified and characterized. In vitro incubation of the purified M6Pase with purified LIP isozyme H2 resulted in its conversion to isozyme H1, with an equimolar release of orthophosphate. Using different sugar phosphates as substrate, the enzyme exhibited narrow specificity, showing activity mostly for mannose 6-phosphate (Km = 0.483 mM). The enzyme displayed a molecular mass of 82 kDa, as determined by gel filtration, and 40.4 and 39.1 kDa, on SDS–PAGE, suggesting that the native form is a dimer. The N-terminal sequence of the enzyme has no homology with that of other reported phosphatases. M6Pase is a metaloprotein with manganese and cobalt as the preferred metal ions. It is N-glycosylated proteins with an isoelectric point of 4.7-4.8 and a pH optimum of 5. Based on its characteristics, M6Pase from P. chrysosporium seems to be a unique phosphatase responsible for posttranslation modification of LIP isozymes.

Effect of anaerobiosis on alcohol dehydrogenase in oat seedlings

In order to clarify the induction of alcohol dehydrogenase (ADH) by anaerobiosis in oat (Avena sativa L.), the seedlings were exposed to anaerobiosis and activity of ADH and ADH isozyme profiles were determined. The anaerobiosis increased ADH activities in shoots and roots of the seedlings. By day 2, the activity increased 5 and 4 times in the roots and the shoots, respectively, compared with those under aerobic condition. Based on nondenaturing electrophoresis, ADH isozyme composition analysis revealed six bands consisting of a dimmer enzyme with submits encoded by three different Adh genes. Changes in staining intensity of the isozymes indicated that the increase in ADH activity in oat under anaerobiosis resulted from increased enzyme synthesis.

Flooding Induced Increase in Alcohol Dehydrogenase Activity in Timothy and Ryegrass Seedlings

Two forage grasses, timothy (Phleum pratense L.) and ryegrass (Lolium multiflorum Lam.) were exposed to flooding, and activities of alcohol dehydrogenase (ADH) and their isozyme profiles were determined. The flooding stress increased ADH activities in both species. This increase was 2-times greater in timothy than in ryegrass. Only one ADH isozyme was found in non-flooded seedlings of both species, whereas two and four bands were identified in ryegrass and timothy seedlings, respectively, under flooding stress.

CYP1A1 and CYP1B1, two hydrocarbon-inducible cytochromes P450, are constitutively expressed in neonate and adult goat liver, lung and kidney.

The ontogeny of cytochrome P-450 isozymes (P450) in goat liver, lung and kidney was studied using anion exchange HPLC separation of solublized microsomal proteins and Western immunoblotting. Comparison of the overall HPLC profile of goat P450 isozymes between liver, lung and kidney showed that while the P450's of goat liver were equally separated into five peaks of isozyme(s), only two peaks constitute the majority of P450 isozyme(s) in lung and kidney, thus demonstrating the tissue specific differences in P450 isozyme distribution in goats. Immunoblotting analysis using polyclonal antibodies against rat CYP1B1, and mouse CYP1B1, polyaromatic hydrocarbon-regulated P450's, revealed that goat orthologs of CYP1A1 and CYP1B1 are expressed constitutively in goats. The CYP1A1 was expressed in goat liver and lung as early as 1st day of age, and the levels of its expression in adult lung and liver were, respectively, 1.3 and 5.5 pmol per mg microsomal proteins. CYP1B1 was expressed in goat livers in substantial levels as of 1 week of age and increased thereafter to reach approximately 4.5 pmol per mg microsomal proteins in adult livers, while low level was detectable only in adult but not neonate lung tissues. Furthermore, polyclonal antibodies against rat CYP1A2 detected very high levels of CYP1A2 in livers of adult and 6 week old goats. The Ah receptor which controls the expression of CYP1A1/1A2 and CYP1B1, was detected in cytosolic fractions from these tissues as a 104 kDa and a minor level of the 106 kDa form. These are potentially very important findings in light of the role of CYP1A1/1A2 and CYP1B1 in activation of polyaromatic hydrocarbons, heterocyclic amines and nitroaromatic hydrocarbons to genotoxic metabolites, and the health consequences of these metabolites on humans, as consumers of goat milk and meat. Using polyclonal antibodies against rat hepatic CYP2B1 and CYP3A1, the goat CYP2B and CYP3A forms were not detectable in livers of goats at any age, but lungs of adult and 6 week old goats expressed these two CYPs in levels equivalent to the livers of phenobarbital-induced rats. On the other hand, anti-rat CYP2C6 antibodies specifically detected two goat ortholog forms which were expressed in all three tissues and exhibited age-dependent changes. In conclusion, results from both immunoblot and HPLC analyses confirmed that, as in other species, the expression of P450 isozymes in goat is under both developmental- and tissue-specific regulatory factors.

Changes in the isozyme composition of antioxidant enzymes in response to aminotriazole in leaves ofArabidopsis thaliana

The changes in isozyme profiles of catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR) during severe deactivation of total CAT activity by aminotriazole (AT) treatment were investigated in the leaves ofArabidopsis thaliana (Columbia ecotype) in relation to H2O2-mediated oxidative stress. In spite of striking deactivation of total CAT activity by 0.1 mM AT, there were no significant differences in H2O2 levels or total leaf soluble protein contents including a Rubisco in both the control and AT-treated leaves. On the other hand, one specific protein band (molecular mass, 66 kD) was observed on the SDS-gel from leaf soluble proteins whose staining intensity was strikingly enhanced by AT treatment for 6 h. However, this band disappeared at 12 h. In the native-gel assays of CAT, POD, APX and GR isozymes, AT remarkably inhibited the expression of the CAT1 isozyme with no effects on CAT2 and CAT3, and generally had no effect on POD isozyme profiles. However, AT stimulated the intensity of activities of pre-existing APX1 and GR1 isozymes. In particular, it induced a new synthesis of one GR isozyme. Therefore, these results collectively suggest that a striking deactivation of total CAT activity by AT inA. thaliana leaves largely results from the suppression of CAT1 isozyme, and that APX1, GR1, and a newly synthesized GR isozyme could complement the role of CAT1 to metabolize H2O2 into non-toxic water.

Minimal growth conservation of potato microplants: silver thiosulfate reduces ethylene-induced growth abnormalities during prolonged storage in vitro

Efficacy of silver thiosulfate (STS) in reducing ethylene-induced culture abnormalities during minimal growth conservation of microplants was studied in seven potato (Solanum tuberosum L.) genotypes. Different concentrations of STS (0, 1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 μg ml–1) were tested in minimal growth medium based on MS medium supplemented with 20 g l–1 mannitol and 40 g l–1 sucrose. STS improved the microplant growth and reduced the culture abnormalities during prolonged maintenance of potato shoot cultures in vitro. The beneficial effect of STS was most prominent for number of green leaves per microplant and leaf senescence. After 16 months of storage, desirable microplant growth was observed in cultures conserved in medium containing 6.0–9.0 μg ml–1 STS. The profile of the peroxidase isozymes of conserved cultures did not show any apparent genetic variation due to the presence of STS in the conservation medium.

Antioxidative responses to different altitudes in Plantago major

The contents of antioxidants were investigated in leaves and in roots of Plantago major, which were collected from different altitudes of Mahan Mountain. A strong correlation between antioxidant content and elevation was observed. As altitude increased, the content of glutathione (GSH) increased both in leaves and in roots, while the activities of guaiacol peroxidase (POX) and superoxide dismutase (SOD) increased only in roots, and declined in leaves. Analyses of isozyme of POX and SOD showed that at high altitude (3300 m) the POX isozyme 5 and the SOD isozyme 8 were induced in roots, but not in leaves. It seemed that the POX isozyme 5 and the SOD isozyme 8 were required for adaptation as the oxidant level increased with lower temperature and higher light intensity as altitude increased. There were no significantly meaningful differences in SOD isozyme profiles and POX isozyme profiles in leaves among three altitudes. These results indicated that Plantago major could not grow at much higher altitude than 3300 m. The present study also suggested that high altitude had different effects on antioxidant system in leaves and in roots.

Comparison of Stenocarpella maydis Isolates for Isozyme and Cultural Characteristics.

Isolates of Stenocarpella maydis from seed companies and plant disease clinics in the United States and the Republic of South Africa were assayed for isozyme polymorphisms and cultural variability. A low level of isozyme polymorphisms was detected in this collection of isolates. Isozyme polymorphisms were detected for α-esterase, hexose kinase, and malate dehydroge-nase of the enzymes assayed. Fungi often have limited variability among isozyme profiles, and this is especially true for fungi that have host specialization such as biotrophs or fungi with formae speciales designations. Optimum growth temperature, colony color, and pycnidiospore production were also measured. All isolates had an optimum temperature of 28 to 31°C for colony growth on acidified potato dextrose agar. Colony color and pycnidiospore production were variable over the course of several experiments, indicating that these phenotypes are poor genetic markers.

Cultivar Identification and Genetic Diversity within a Hatiora (Cactaceae) Clonal Germplasm Collection Using Isozymes

Isozyme markers were used to identify cultivars and assess the genetic diversity within a germplasm collection of 49 Hatiora Britt. & Rose clones. The collection included accessions of Easter cactus [H. gaertneri (Regel) Barthlott, H. graeseri Barthlott ex D. Hunt, and H. rosea (Lagerheim) Barthlott] plus H. herminiae (Campos-Porto & Castellanos) Backeberg ex Barthlott and H. salcornioides (Haworth) Britton & Rose. Seven enzyme systems were analyzed: aspartate aminotransferase, glucose-6-phosphate isomerase, leucine aminopeptidase, malate dehydrogenase, phosphoglucomutase, shikimate dehydrogenase, and triosephosphate isomerase. Thirteen loci and 42 alleles were identified. Twenty-one clones (43%) displayed unique isozyme profiles, but the remaining 28 clones shared isozyme profiles with one to three other clones. Percent polymorphic loci, mean number of alleles per locus, and mean heterozygosity were 69, 3.23, and 0.30, respectively, for the entire collection. Isozymes also proved useful for verifying that some progeny were genuine F1 hybrids.

Fine structure of the flagellar apparatus and morphological details of Gymnodinium nolleri sp. nov. (Dinophyceae), an unarmored dinoflagellate producing a microreticulate cyst

A naked dinoflagellate producing microreticulate cysts is described as Gymnodinium nolleri sp. nov. It was previously misidentified as Gymnodinium catenatum based on strong morphological similarity with this species in both the cyst and motile stages. Gymnodinium nolleri differs from G. catenatum primarily in the size of the cyst and the vegetative stage, G. nolleri being smaller, although there is overlap, particularly in the size of the vegetative cell. The cyst of G. nolleri is 28–38 μm in diameter, whereas G. catenatum measures 38–59 μm. The vegetative cell of G. nolleri on average is 26 × 33 μm and G. catenatum is 36 × 45 μm. The motile stage of G. nolleri never forms long chains, whereas such chains are common in G. catenatum. The cyst of G. nolleri has fewer rows of polygons in the paracingulum than G. catenatum, and the polygons on the cyst are generally slightly smaller, although they appear larger due to the smaller size of the cyst. These differences and earlier described differences at the molecular level (large subunit ribosomal RNA sequence, isozyme profile, lack of paralytic shellfish poisoning (PSP) toxins in G. nolleri) justify describing G. nolleri as a new species. The fine structure of the flagellar apparatus of G. nolleri is included in the description. It shows features common to most dinoflagellates studied so far and has many similarities with the flagellar apparatus of ‘Gymnodinium sp.' of Roberts (1986) and G. catenatum, e.g. a nuclear fibrous connective, longitudinal microtubular root–longitudinal basal body connectives, and a longitudinal microtubular root–ventral ridge connective.

Differential expression of DAHP synthase and chorismate mutase in various organs of Brassica juncea and the effect of external factors on enzyme activity

The multibranched shikimic acid pathway was discovered as the biosynthetic route to the aromatic amino acids phenylalanine, tyrosine and tryptophan and a host of other secondary metabolites. An extensive body of work is available on the characterization of various enzymes of this pathway in order to understand the underlying mechanisms of aromatic amino acid biosynthesis and secondary metabolism in higher plants. In the present investigation, selective assays, based on feedback regulation patterns and divalent cation requirements, were used to monitor the isozyme profiles of two of the key regulatory enzymes of this pathway. 3‐Deoxy‐ d‐arabino heptulosonate‐7‐phosphate synthase (DAHP synthase/DS) (EC 4.1.2.15) and chorismate mutase (CM) (EC 5.4.99.4) have been characterized from different vegetative and reproductive organs of Brassica juncea cv. Pusa Bold. An attempt has also been made to investigate the effect of external factors, such as light and wounding on the regulation of these enzymes. The results reveal differential expression of DAHP synthase and CM in various organs of Brassica and an adaptability of plants to various stresses by up or down regulation of these enzymes.

Meiotic Chromosome Pairing, Isozyme Analyses and Ferritin Expression in a Red Clover Mutant Capable of Somatic Embryogenesis

Red clover genotypes capable of regenerating plantletsin vitrofrom non-meristem-derived callus are rare. A previous study identified a pair of near isogenic lines which were derived from a single seed but differed in regenerative ability. The callus-derived plants of this clone were highly regenerative when reintroduced to culture whereas the epicotyl-derived plants produced non-regenerative callus cultures. The objective of the present study was to observe meiotic chromosome pairing and to compare isozyme profiles and ferritin gene expression in regenerative and non-regenerative plants and cultures from the clone. Meiotic cells exhibited normal homologous chromosome pairing. Starch gel zymograms from glasshouse-grown regenerative (F49R) and non-regenerative (F49M) plants failed to show somaclonal variation for alcohol dehydrogenase, glutamate dehydrogenase, esterase or peroxidase. Isoelectric focusing of callus cultures from regenerative and non-regenerative plants revealed that regeneration was accompanied by a reduction in staining intensity and numbers of peroxidase bands compared to non-regenerative cultures. A unique cathodic peroxidase band (pI 7.6) was associated with non-regenerative cultures. Ferritin expression was greater in callus than in fresh petiole tissue. Ferritin expression remained high in non-regenerative callus cultures but declined in regenerative cultures as regeneration progressed.

The Myocardial Profile of the Cytosolic Isozymes of Creatine Kinase Is Apparently Not Related to Cyanosis in Congenital Heart Disease

CKMB, the cardiac-specific heterodimer of cytosolic creatine-kinase (CK), is developmentally and physiologically regulated, tissue hypoxia being a proposed regulator. In patients with cyanotic heart disease the myocardium is perfused with partially saturated blood. We questioned whether the myocardium of cyanotic subjects contains higher proportions of CKMB. CK activity, the distribution of cytosolic CK isozymes, activity of lactic dehydrogenase (LDH), and tissue protein content were determined in obstructive tissues removed at corrective surgery of patients with congenital heart defects. Cyanotic (n = 13) and acyanotic (n = 12) subjects were compared. In cyanotic and acyanotic patients, CK activity was 8.4 +/- 0.6 and 7.6 +/- 0.6 IU/mg protein and the proportion of CKMB was 21 +/- 1.4 and 22 +/- 2. 0% (mean +/- S.E.M), respectively. In the two groups of patients, the activity related to the B subunit corresponded to the steady-state level of the CKBmRNA. The tissue content of protein and the activities of CK and LDH were similar in cyanotic and acyanotic subjects and increased with the age. The lack of difference in CKMB distribution between the cyanotic and acyanotic patients may either indicate that hypooxygenation is not a regulator of CK isozyme expression, or may be attributed to the already high proportion of this isozyme in hypertrophied, obstructive tissues. Recruitment of additional CKMB, in the cyanotic hearts, may thus not be required.

Changes in lactate dehydrogenase and 3-hydroxyacetyl-CoA dehydrogenase activities in rat skeletal muscle by the administration of Eucommia ulmoides OLIVER leaf with spontaneous running-training.

We examined the effect of Eucommia ulmoides OLIVER leaf on rat skeletal muscles together with spontaneous running-training in terms of the isozyme profile and specific activity of lactate dehydrogenase (LDH; EC 1.1.1.27) and 3-hydroxyacetyl-CoA dehydrogenase (HAD; EC 1.1.1.35). On the twenty-ninth day of the experimental period, a mandatory endurance running exercise (treadmill, 7 degrees grade) was conducted. Twenty-four hours later, the rats were sacrificed and the skeletal muscles and other organs were dissected. Due to the training, the HAD specific activity in the skeletal muscles had increased and a more oxidative metabolism had developed, which was further enhanced by the administration of the leaf. In soleus (SOL) muscle in the Eucommia leaf treated running-training group (ET), the LDH specific activity in the skeletal muscle was significantly higher than in the sedentary control group (SC). The isozyme profile of the group ET was significantly different when compared with the group SC. The changes in the LDH isozyme profile were larger in the SOL than that in extensor digitorum longus (EDL) muscle. The results show that mechanical training and the use of the leaf cooperatively increase the ability to avoid lactate accumulation in skeletal muscle. This effect is supported by the group where 67% of rats accomplished the endurance running exercise. Theses results suggest that the administration of Eucommia ulmoides OLIVER leaf along with light intensity training enhances the ability of a muscle to resist fatigue.

Xylanase production by Thermomyces lanuginosus wild and mutant strains

Thermomyces lanuginosus strains from different culture collections, namely ATCC 26909, ATCC 22083, DEN 1457, IMI 84400 and BS1 were compared for xylanase production, and isozyme profile. Of all the strains of T. lanuginosus, BS1 a soil isolate produced the largest amount of xylanase. All strains were found to produce two forms of xylanase (I & II) with molecular mass corresponding to 25.0 and 54.0 KDa. The u.v/NTG mutagenesis of T. lanuginosus BS1 aleurospores/protoplasts resulted in xylanase-hyperproducing mutants. A morphological colour mutant RB 524 produced approximately 2.5-fold higher xylanase (2506.0 units/ml) as compared to the parent strain (1018.1 units/ml).

Juncus anthelatus (Juncaceae, Juncus subg. Poiophylli), a New Status for a North American Taxon

The taxon long known as Juncus tenuis Willdenow var. anthelatus Wiegand differs from J. tenuis in morphology (it is more robust than J. tenuis, with a more diffuse inflorescence and slightly smaller capsules), habitat, flowering time, and isozyme profile, and should be treated as a distinct species, Juncus anthelatus (Wiegand) R. E. Brooks,

Using microsatellites, isozymes and AFLPs to evaluate genetic diversity and redundancy in the cassava core collection and to assess the usefulness of DNA-based markers to maintain germplasm collections

The cassava core collection was selected to represent, with minimum repetitiveness, the potential genetic diversity of the crop. The core (630 accessions) was chosen from the base collection (over 5500 accessions) on the basis of diversity of origin (country and geographic), morphology, isozyme patterns and specific agronomic criteria. To asses the genetic diversity of the core, 521 accessions were typed with four microsatellite loci. Allele diversity and frequency, and size variance of dinucleotide repeats (Rst statistic) were estimated. Microsatellite allele numbers and frequencies varied among countries: Colombia and Brazil had the largest number of different alleles across all loci. Mexico also had a high number, ranking fifth after Peru, Costa Rica and Venezuela (which tied). Unique alleles were present in accessions from Brazil, Colombia, Guatemala, Venezuela and Paraguay. A small number (1.34%) of potential duplicates were identified through isozyme and AFLP profiles. Thus, the present results indicated that traditional markers have been highly effective at selecting unique genotypes for the core. Future selections of cassava germplasm sets can be aided by DNA-based markers to ensure genetically representative, non-redundant samples.

A major gene controlling pathogenicity inBotryotinia fuckeliana(Botrytis cinerea)

Non-aggressive mutants were isolated from a single-ascospore strain ofBotryotinia fuckelianafollowing ultraviolet and chemical mutagenesis of conidia and screening on French bean leaves (Phaseolus vulgaris). Crosses with reference strain SAS56 revealed one ultraviolet induced mutant (Mp97) in which the non-aggressive phenotype segregated 1:1 indicating control by a single gene with a major effect on pathogenicity. Further crosses showed that this gene, designatedPat1, is not linked toMbc1(benzimidazole resistance),Daf1(dicarboximide resistance),nit1(nitrate non-utilising), orSel1(sodium selenate resistance). The pathogenicity ofPat1strains was compared with various wild-type strains. Mutant strains produced small, restricted lesions on leaves of French bean and soybean (Glycine max) and slowly spreading lesions on rose (Rosaspp.) flowers. The mutant was essentially non-pathogenic on tomato stems at 20 and 25 °C but produced a few invasive infections at 10 and 15 °C. Tests of radial growth rate, sporulation and sclerotial production showed thatPat1strains exhibit no gross unfitness or unusual nutrient requirement. Althoughin vivostudies showed substantially less total polygalacturonase activity inPat1lesions compared to those produced by wild-type strains, differences in polygalacturonase isozyme profiles were not correlated with the presence ofPat1.Pat1strains showed relatively low acid production in pH indicator medium. Microscopic examination showed that lesions induced by the Mp97 mutant on French and soybean leaves (4 days old), but not by its parent, were surrounded by a distinct staining zone of mesophyll cells suggesting a difference in host response. However, no differences in phytoalexin induction were found in a soybean assay.

Genetic diversity in cucumber (Cucumis sativus L.): IV. An evaluation of Chinese germplasm1

Genetic variation in cucumber (Cucumis sativus L. var. sativus) accessions from China was assessed by examining variation at 21 polymorphic isozyme loci. One hundred and forty-six Chinese accessions acquired by the U.S. National Plant Germplasm System (NPGS) before 1994 were compared to 67 recently collected Chinese accessions. Of the 67, 39 were collected during a 1994 U.S.–China expedition and 28 were donated in 1996. Isozymic profiles of all of these Chinese accessions were also compared with 853 previously examined NPGS cucumber accessions. Principal component analysis of allele frequencies identified two distinct groups of Chinese accessions: one containing accessions collected in 1994 (Group 1) and the other containing accessions received by NPGS in 1996 (Group 2) (P<0.01). Variation at Gpi, Gr, Mdh-2, Mpi-2, Pep-gl and Pep-la was important in the detection of this difference. Isozymic variation in U.S. NPGS accessions of Chinese origin acquired before 1994 differed significantly (P<0.01) from those collected during 1994 and those received in 1996. Eleven loci (Fdp-1, Gpi, Gr, Idh, Mpi-2, Pep-gl, Pep-la, Pep-pap, Per, Pgm and Pgd-1), were important in the detection of this difference. When Chinese accessions taken collectively (i.e., those acquired before 1994, and those during 1994 and 1996) were compared with an array of 853 C. s. var. sativus accessions examined previously, relationships between accessions grouped by country or subcontinent differed from those found in the previous work. Accessions from China and India were distinct from each other and from all other groupings and the C. s. var. hardwickii (feral form of C. s. var. sativus) accessions examined. Thus, Chinese and Indian accessions represent the most diverse genetic variation present in the NPGS cucumber collection. Further collection in India and China would be strategically important for increasing genetic diversity of the U.S. NPGS cucumber collection.

LCC15-MB: a vimentin-positive human breast cancer cell line from a femoral bone metastasis.

The LCC15-MB cell line was established from a femoral bone metastasis that arose in a 29-year-old woman initially diagnosed with an infiltrating ductal mammary adenocarcinoma. The tumor had a relatively high (8%) S-phase fraction and 1/23 positive lymph nodes (LN). Both the primary tumor and LN metastasis were positive for estrogen receptor (ER) and progesterone receptor (PgR), but lacked erbB2 expression. Approximately one year later, the patient presented with a 0.8 cm comedo-type intraductal mammary adenocarcinoma in the left breast that was negative for ER and PgR, but positive for erbB2. Thirty-five months after the initial diagnosis she was treated for acute skeletal metastasis, and stabilized with a hip replacement. At this time, tumor cells were removed from surplus involved bone, inoculated into cell culture, and developed into the LCC 15-MB cell line. The bone metastasis was a poorly differentiated adenocarcinoma lacking ER, PgR, and erbB2, characteristics shared by the LCC15-MB cells, although ER can be re-expressed by treatment of the LCC15-MB cells for 5 days with 75 microM 5-aza-2'-deoxycytidine. The LCC15-MB cell line is tumorigenic when implanted subcutaneously in NCr nu/nu mice and produces long-bone metastases after intracardiac injection. Although the bone metastasis from which the LCC15-MB cell line was derived lacked vimentin (VIM) expression, the original primary tumor and lymph node metastasis were strongly VIM positive, as are LCC15-MB cells in vitro and in nude mice. The karyotype and isozyme profiles of LCC15-MB cells are consistent with its origin from a human female, with most chromosome counts in the hypertriploid range. Thirty-two marker chromosomes are present. These cells provide an in vitro/in vivo model in which to study the inter-relationships between ER, VIM, and bone metastasis in human breast cancer.