Variation in N-linked carbohydrate chains in different batches of two chimeric monoclonal IgG1 antibodies produced by different murine SP2/0 transfectoma cell subclones

Two chimeric human/murine monoclonal antibodies were constructed by substitution of the murine constant regions with human 1 and constant regions for heavy and light chains, respectively. The chimeric human/murine molecules are anti-idiotypic antibodies, meaning that they were directed against the antigen binding site in the variable region of another antibody. Antibody batches were produced under identical production conditions, using two selected SP2/0 myeloma cell subclones, which produce chimeric antibodies with different variable regions, but identical constant regions. Several samples were collected during the production of the antibodies in hollow-fibre reactors. The heavy chain, but not the light chain, of the two different chimeric IgG1 antibodies is glycosylated. Structural analysis of the enzymically released N-linked carbohydrate chains by¹H-NMR spectroscopy, as well as by chromatographic profiling, demonstrated that the collection of N-glycans comprises a small amount of monoantennary, and for the greater part diantennary structures. The N-glycans are completely (1 6)-flucosylated at the innermost GlcNAc residue. The antennae of the neutral diantennary N-glycans are built up from GlcNAc12, Gal1 4GlcNAc1 2 or Gal1 3G11 4GlcNAc1 2 elements, whereas the antennae of the neutral monoantennary carbohydrate chains have only (1 2)-linked GlcNAc residues. Galactosylation of the GlcNAc1 2Man1 6 branch occurs four times more frequently than that of the GlcNAc1 2Man1 3 branch, independently of the production batch. A small amount of the diantennary N-glycans are mono- or disialylated, carryingN-acetylneuraminic acid (Neu5Ac) orN-glycolylneuraminic acid (Neu5Gc), exclusively (2 6)-linked to Gal. Analysis of the different production batches demonstrates that the structures of the N-linked carbohydrate chains are identical in the two chimeric antibodies, but that the relative amounts of the major oligosaccharide components, the degree of sialylation and the molar ratio of Neu5Ac to Neu5Gc varies with the SP2/0 cell subclone, and only slightly with cell age.     

Das organische Gerüstwerk der Kalkschale des Schwanen-Eies

Zusammenfassung Kegel und Säulen der Schwanen-Eischale hinterlassen am Querschliff nach Entkalkung mit EDTA organisches (mucoproteides) Material als ein zusammenhängendes Gerüst, das sich mit Thionin metachromatisch färbt; ohne Demineralisierung oder wenigstens Anätzung bleibt Thionin an Schliffen und Bruchkanten der Schale wirkungslos. Das Lichtmikroskop zeigt an Schliffen nichts von dem organischen Material, es wurde während des Kristallwachstums fein zerteilt in Gitterlücken des Schalencalcits eingeschlossen. Es findet sich am stärksten angehäuft an den äueren und inneren Oberflächen der Kristall-individuen. In den Kegeln ist das Gerüst radial ausgebildet als die Loculi der Keile, und konzentrisch geschichtet, entsprechend den Lagen der Globularinklusionen, um deren jede herum Verdichtung der organischen Substanz statthat. In den inneren Säulen folgt das organische Gerüst dem Rhombenmuster; die äueren Säulen sind arm an organischer Substanz, hier verbleibt nach der Entkalkung eine dünne laterale Oberflächenschicht.

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Summary The cones and columns of the swans egg shell leave behind after decalcification with EDTA an organic (mucoproteid) material in form of a continuous frame work stainable metachromatically with thionine. Without demineralisation or at least etching, thionine proves ineffectual in ground sections or breaking edges of the shell. In ground sections the light microscope demonstrates nothing of the organic material: it was inclosed during the crystal growth in submicroscopical lattice gaps of the calcite individuals. The organic material is chiefly accumulated in the outer and inner surfaces of the crystals. In the cones the organic frame work is developed radially as the loculi of the wedges and concentrically layered corresponding with the globular inclusions, concentrated in the circumference of each. In the inner columns the organic material follows to the rhomb pattern. The outer columns after decalcification only leave behind a thin lateral organic sheath.

     

Holling's “hungry mantid” model for the invertebrate functional response considered as a Markov process. Part II: Negligible handling time

In this paper we analyse a stochastic model for invertebrate predation taking account of the predator's satiation. This model approximates Holling's hungry mantid model when handling time is negligible (see Part I). For this model we derive equations from which we can calculate the functional response and the variance of the total catch. Moreover we study a number of approximations which can be used to calculate these quantities in practical cases in a relatively simple manner.List of Notation a rate constant of digestion - b maximum of rate constant of prey encounter in the mantid - c satiation threshold for search - c satiation threshold for pursuit in the mantid - c _i (w^1/2(N- N)ⁱ) - expectation operator - f rate of change of satiation during search - F functional response: mean number of prey eaten per unit of time - g rate constant of prey capture - h probability generating function of N conditional on S = s times p - H probability generating function of N - m_i ¹ - n, N number of prey caught - p probability density of S - p_n simultaneous probability (density) of N and S - q probability of strike success - r dummy variable in generating function - s, S satiation - T _s search time - T _d digestion time - v asymptotic rate of increase of var v - V asymptotic rate of increase of var N - w weight of edible part of prey - W standard Wiener process - x prey density - z (N{S = s}-N)p - rate constant of prey escape time maximum pursuit time - (v{S = + w ^1/2}-v) - present time as a fraction of the time from the start to the end of the experiment - hazard rate of T _s - mean time between (downward) passages of S through c - v w_–1/2(N-) - edible prey biomass density - probability density of , number pi - parameter of Weibull distribution of T _s = (1/2acx(-g(c)))_1/2 - w_–1/2(S -) - satiation in the guzzler approximation: solution to d/dt = f() + g(), (0)=S(0). - biomass functional response: wF - total biomass catch in the guzzler approximation: solution to d/dt = g(), (0) = 0     

Cajaflavanone and cajanone released from Cajanus cajan (L. Millsp.) roots induce nod genes of Bradyrhizobium sp.

A broad-host-range plasmid (pEA2-21) containing a Bradyrhizobium sp (F-4) nod DABC-lacZ translation fusion was constructed and used to monitor nod gene expression in response to pigeonpea root exudate. Two nod-inducing compounds were isolated and identified. Spectral analysis using ultraviolet absorption, infrared spectra, proton nuclear magnetic resonance, and mass spectrometry showed that the two inducers were 5,4-dihydroxy-6-(3-methyl-2-butenyl)-2, 2-dimethyl pyrano-[5, 6:7, 8]-flavanone (cajaflavanone) and 2,4,5-trihydroxy-5-isopentenyl-6, 7-dimethylchromene iso-flavanone (cajanone). When pEA2-21 was introduced into Rhizobium trifolii and R. meliloti cajanone and cajaflavanone did not induce nod gene indicating that specificity of induction appears to be influenced by the host-strain genome.     

Comparative study on the chloroplast,mitochondrial and nuclear genome differentiation in two cultivated rice species,Oryza sativa and O. glaberrima,by RFLP analyses

Summary Restriction fragment length polymorphisms of chloroplast (ct), mitochondrial (mt) and nuclear DNA were investigated using eight cultivars of Oryza sativa and two cultivars of O. glaberrima. Relative variability in the nuclear and cytoplasmic genomes was estimated by a common measure, genetic distance. Based on the average genetic distances among ten cultivars for each genome, the evolutionary variabilities of the mitochondrial and nuclear genomes were found to be almost the same, whereas the variability of the chloroplast genome was less than half that of the other two genomes. Cluster analyses on ct and mt DNA variations revealed that chloroplast and mitochondrial genomes were conservative within a taxon and that their differentiations were well-paralleled with respect to each other. For nuclear DNA variation, an array of different degrees of differentiation was observed in O. sativa, in contrast with little variation in O. glaberrima. As a whole, differentiation between O. sativa and O. glaberrima was clearly observed in all three genomes. In O. sativa, no notable difference was found between the cultivars Japonica and Javanica, whereas a large differentiation was noticed between Japonica (including Javanica) and Indica. In all three genomes, the average genetic distances within Indica were much larger than those within Japonica (including Javanica), and almost similar between Japonica (including Javanica) and Indica. These facts indicate that differentiation in O. sativa was due mainly to Indica.     

The structure of the incompatibility factors of Schizophyllum commune: Constitution of the three classes of B factors

Summary The B factors of Schizophyllum commune are of 3 classes: The high recombining class I has 7 alleles and 7 alleles; the low recombining classes are class II with 7 allels and probably 2 alleles and class III with probably 2 (or also 2) alleles and 7 allels. A fourth hypothetical class (-) was not found and either does not exist or is indistinguishable from class III by the tests employed. The and alleles differ from and by either (a) mutations affecting both mating specificity and recombination frequency, or (b) deletions involving most of the B region.The research was supported by a grant from the Atomic Energy Commission of the U.S. No. (30-1)-3875 and was performed at the Biological Laboratories, Harvard University, Cambridge, Mass., U.S.A.     

Variability in the 11S globulin fraction of seed storage proteins ofHelianthus (Asteraceae)

The seed storage globulins from sixHelianthus and four hybrids were studied using mono and bidimensional gel SDS electrophoresis (+ 2 mercaptoethanol). The polypeptide composition of each subunit was determined. Different pairs are specifically expressed according to the species studied. Three typical patterns were discriminated. All the studied species exhibit five subunits: two of them are expressed in all the species (₁₁ and ₂₂). The subunit corresponding to the ₁₁ pair is present inH. petiolaris and in the three populations ofH. annuus studied. The _2b2 pair is common toH. annuus andH. argophyllus. H. petiolaris presents two specific _2a2 and ₄₄ pairs andH. annuus a specific ₃₃ pair. InH. argophyllus _{11 33} or ₄₄ are never observed but are replaced by ₁₃ and ₃₁ pairs. Some globulins, poorly represented, are of forms but present chains of higher molecular weights (in the range 54–56 kDa). Expressing variations in the banding patterns between these species by the use of a similarity index reveals complete identity between the three populations ofH. annuus. Identity between the twoH. petiolaris studied is also observed.H. annuus andH. argophyllus appear to be closer to each other thanH. petiolaris concerning the seed storage globulins.     

Unique sequences for two HLA-DRB1 genes expressed on distinct DRw6 haplotypes

We have used restriction fragment length polymorphism (RFLP) analysis and DNA sequencing to characterize two distinct DRB1 alleles expressed on DRw52 and DQw7-associated haplotypes but not readily defined by conventional DR serology. These two haplotypes, designated HLA-D HAG and PEV, react variably with DRw13(w6), DRw14(w6), and the more broad DR 3+6 antisera. Analysis of RFLP revealed that HLA-D HAG and PEV are associated with different DRw52 variants, and that HAG is indistinguishable from DRw18(3) haplotypes. Sequencing of the HAG and PEV DRB1 genes showed each to represent novel alleles. Nevertheless, these sequences show similarities with the other alleles of the DR5, w6, and w8 family. HAG (DRB1*1303) appears to have arisen either from two recombinational events involving at least three DRB1 sequences (DRB1*1101, DRB1*0803, DRB1*0401) or from a single recombinational event together with multiple point mutational events. PEV appears to represent a DRB1*1301-1302/DRB1*1101 recombinant allele, with recombination having occured in the region of bases 175 – 198. The results of this study suggest that the DRw52 family haplotypes is derived from a relatively restricted number of ancestral sequences, with diversity among DRB1 alleles within this family arising through gene conversion or recombination events.     

Microsatellite markers in the hexaploid Prunus domestica species and parentage lineage of three European plum cultivars using nuclear and chloroplast simple-sequence repeats

In a previous study, cDNA microsatellite markers were described in apricot (Prunus armeniaca L.). Specific PCR primers were designed to amplify the microsatellite-containing regions from genomic DNA in different Prunus species. In the present work, cDNA microsatellite markers were developed in the hexaploid Prunus domestica L. species and polymorphism was ascertained in a segregating plum population. Co-dominant mendelian segregation of alleles was demonstrated and microsatellite polymorphism displayed up to 6 alleles per SSR locus per individual. Parentage lineage of three full-sib European plum cultivars (cv. Cacanska najbolja, Cacanska rana and Cacanska lepotica) was reconstructed by the analysis of the above nuclear SSR markers, completed by four chloroplastic microsatellite loci. The six most informative nuclear loci enabled discrimination between the three Cacak cultivars and unrelated individuals as well as the previously proposed parents, Wangenheim and Pozegaca. Data obtained support previous evidence that these cultivars originated from the Stanley cultivar. However, SSR analysis finally excluded Wangenheim as the other possible parent. Based on the results obtained with nuclear and chloroplast SSR loci, we propose the origin of those three Cacak cultivars in a cross between Stanley as the mother plant and Ruth gerstetter as the pollinator. Furthermore, we demonstrate the utility of these apricot SSR markers for genotype fingerprinting of the hexaploid plum cultivars.     

Production of a novel syrup containing neofructo-oligosaccharides by the cells of Penicillium citrinum

A novel syrup containing neofructo-oligosaccharides was produced from sucrose (Brix 70) by whole cells of Penicillium citrinum. The efficiency of fructo-oligosaccharides production was more than 55% and those of the main carbohydrate components, 1-kestose (Fruf 21Fruf 21 Glc), nystose (Fruf 21Fruf 21 Fruf 21 Glc) and neokestose (Fruf 26 Glc12 Fruf), were 22, 14 and 11%, respectively.     

Diversity of the mouse T cell receptor Cγ1 gene: structural analysis in C57BL/Ka

We have isolated an unusual T cell receptor chain cDNA clone (7.1) from a library made from RNA derived from adult thymus of C57BL/Ka mice. This cDNA clone corresponds to the appropriately processed C1 constant region exons preceded by 1.5 kb of J-C1 intron. The 7.1 coding region is extremely homologous to the C1 gene of BALB/c mice, differing at the protein level by a single deletion (alanine 139) and a single substitution. This latter change eliminates the sole N-linked sugar attachment site, providing a basis for strain-specific glycosylation patterns. The J-C1 intronic region contains two DNA segments (termed J1 and J2) that are highly reminiscent of joining (J) segments; both have potentially functional recombination and donor splice sequences flanking an open reading frame. Northern analysis suggests that 7.1 may be derived from a large, variable region-containing precursor.     

Development of high frequency multiple shoot formation in Persian clover (<Emphasis Type="Italic">Trifolium resupinatum</Emphasis> L.)

An efficient and reliable micropropagation system for Persian clover (Trifolium resupinatum L.) was developed using different explants and media. Node, hypocotyl and cotyledonary node explants were cultured on Murashige and Skoog (MS) medium supplemented with combinations of either 6-benzyladenine (BA) and indole-3-butyric acid (IBA) or BA, Kinetin (KIN) and IBA. Direct multiple shoots developed within 6weeks in all explants in most media tested. The best shoot multiplication capacity was obtained from cotyledonary node explants on MS medium containing 7.1M BA and 1M IBA or 14.1M BA and 1M IBA. Elongated shoots were rooted on either MS medium alone or combination with different concentrations of indole-3-butyric acid (IBA), indole-3-acetic acid (IAA) and -naphthaleneacetic acid (NAA). High rooting was achieved in half strength MS medium containing 8M IBA.     

The carotenoids of Flavobacterium strain R1560

The main carotenoid of Flavobacterium strain R1560 has been identified as (3R,3R)-zeaxanthin. Also present were small amounts of 15-cis-phytoene, phytofluene, -carotene (7,8,7,8-tetrahydro-, -carotene plus 7,8,11,12-tetrahydro-, -carotene), neurosporene, lycopene, -zeacarotene, -carotene, -carotene, -cryptoxanthin, rubixanthin, 3-hydroxy--zeacarotene and several apo-carotenals. Zeaxanthin production was inhibited by nicotine (10 mM), and lycopene and rubixanthin accumulated. The biosynthesis of zeaxanthin is discussed in terms of pathways and also of half-molecule reaction sequences. The presence of zeaxanthin may be a characteristic of a group of Flavobacterium species, and may thus be useful in the taxonomic classification of these organisms.     

A highly-sensitive rice seedling bioassay for the detection of femtomole quantities of 3β-hydroxylated gibberellins

A very sensitive and specific bioassay using prohexadione calcium [BX-112, which blocks 2- and 3-hydroxylation of gibberellins (GAs)] with uniconazole (which blocks oxidation of ent-kaurene, ent-kaurenol and ent-kaurenal) in a microdrop assay was developed for several rice (Oryza sativa L.) varieties, including cv. Waito-C, which is already specific to 3-hydroxylated GAs. The sensitivity and specificity of cvs. Waito-C, Tan-ginbozu and Koshihikari to 3-hydroxylated GAs was greatly enhanced by treatment of the seeds with a combination of 40 mM prohexadione calcium and 80 M uniconazole. The minimum detectable doses of 3-hydroxylated GAs (GA₁, GA₃, GA₄ and GA₇) in the three cultivars treated with both chemicals were 1 to 10 fmol (i.e. ca. 350 fg to 3.5 pg) per plant. This is equal to 30-fold more sensitive than Waito-C treated with uniconazole alone, and 30 to 1000-fold more sensitive than Waito-C with no growth retardant soak. Minimum detectable doses of 3-nonhydroxylated GAs (GA₉, GA₁₉ GA₂₀) and GAs with very low biological activity (GA₈ and GA₁₇) were equal to or more than 1000 fmol per plant. This is about equal to the activity in Waito-C treated with uniconazole alone. Application of this assay to an extract from Raphanus sativus was compared with the data by gas chromatography/mass spectrometry (GC/MS), confirming the conclusions reached using authentic test GAs, namely that use of uniconazole plus BX-112 appreciably enhanced the detection sensitivity to fractions shown by GC/MS to contain GA₁ and GA₄, both 3-hydroxylated GAs.Abbreviations GA gibberellin - BX-112 prohexadione calcium     

<Emphasis Type="Italic">In vitro</Emphasis> screening of sugarcane to evaluate smut susceptibility

Tissue-cultured plantlets of three sugarcane (Saccharum spp.) cultivars having a known field smut reaction were screened for susceptibility to Ustilago scitaminea H&P Sydow. Plantlets were inoculated with 0.5 l of a suspension of equally mixed quantities of plus and minus mating type sporidia of U. scitaminea at concentrations ranging from 1×10¹ to 1×10⁶ cells. Fungal sori (whips) were produced in cultivar N12 (intermediate) 6weeks following inoculation with 1×10⁵ mixed sporidia and thereafter in cultivar NCo310 (susceptible) but not in cultivar N19 (resistant). Sori bearing teliospores were produced up to 3months following inoculation and incubation at 26°C. No sori were produced at mixed sporidial concentrations lower than 1×10⁵cells. The in vitro soral production in cultivars N19, N12 and NCo310 was 0, 27.5 and 47.5% respectively. Plantlets inoculated with 1×105sporidia of only one mating-type did not produce sori in any of the three cultivars tested. Blind scoring of an unknown sugarcane cultivar by this method corresponded exactly with its field smut rating.     

The glycolipid specificity ofErythrina cristagalli agglutinin

The interaction of¹²⁵I-labeledErythrina cristagalli agglutinin (ECA) with neutral glycosphingolipids on thin layer chromatograms was examined by the overlay technique followed by radioautography. The lectin bound topara-globoside with a sensitivity about 10 times higher than to lactosylceramide or globoside, in agreement with the specificity of the lectin forN-acetyllactosamine. The lower limit of detection ofpara-globoside was about 0.66 nmol. The specific binding of ECA to this glycolipid was confirmed by a highly sensitive enzyme-linked lectin assay (ELLA), utilizing the horseradish peroxidase-avidin-biotin system for detection of bound lectin. Overlays of neutral glycosphingolipid extracts from human erythrocyte membranes and from human granulocytes with ECA demonstrated that the lectin can be employed for the detection of small amounts ofpara-globoside in biological materials also in the presence of excess globoside. No staining was obtained when thin layer chromatograms of neutral glycosphingolipid extracts from rabbit erythrocyte membranes were overlayed with¹²⁵I-ECA. Afterin situ treatment of the chromatograms with -galactosidase, the lectin bound to several components, one of which had a mobility corresponding to that of the pentahexosylceramide Gal3Gal4GlcNAc3Gal4Glc1Cer, the major neutral glycosphingolipid of rabbit erythrocytes, thus providing further evidence for the specificity of ECA forpara-globoside.Abbreviations GSL glycosphingolipid(s) - CDH lactosylceramide, Gal4Glc1Cer - CTH trihexosylceramide, Gal4Gal4Glc1Cer - GLOB globoside, GalNac3Gal4Gal4Glc1Cer - PG para-globoside, Gal4GlcNAc3Gal4Glc1Cer - AsG_M1 asialo-G_M1, Gal3GalNAc4Gal4Glc1Cer - FORS Forsmann antigen, GalNAc3GalNAc3Gal4Gal4Glc1Cer - CPH pentahexosylceramide, Gal3Gal4GlcNAc3Gal4Glc1Cer - ECA Erythrina cristagalli agglutinin - SBA soybean agglutinin - PBS phosphate-buffered saline - PVP-40 polyvinylpyrrolidone M.W. 40000 - BSA bovine serum albumin - HRP-avidin horseradish peroxidase conjugated to avidin - ELLA enzyme-linked lectin assay - ELISA enzyme-linked immunosorbent assay - PMNL polymorphonuclear leukocytes - HPTLC high performance thin layer chromatography     

Andaman Islanders,Pygmies, and an extension of Horn's model

Horn's model is generalized to state that the optimal pattern of distribution for foragers will correlate with the degree of resource patchiness; in particular (1) where resource attributes are less patchy, the optimal distribution for foragers is to be dispersed, and (2) where resource attributes are more patchy, the optimal distribution for foragers is to be aggregated. Optimality is assessed as the minimum round-trip distance from the forager's home base to a resource item. Patchiness is assessed according to the state taken by any of four resource attributes: dispersion (in space), supply (in time), particle size, and lasting properties. Horn's original contrast between (1) stable and evenly dispersed resources, and (2) mobile and clumped resources is shown to have been internally contradictory; that is, the optimal distribution for foragers would have been the same in both cases.     

Retinoic acid receptor isoform RARγ 1: an antagonist of the transactivation of the RARβ RARE in epithelial cell lines and normal human keratinocytes

The diversity of isoforms of retinoic acid (RA) receptors (RARs) and of DNA sequences of retinoic acid-responsive elements (RAREs) suggests the existence of selectivities in the RAR/RARE recognition or in the subsequent gene modulation. Such selectivities might be particularly important for RAREs involved in positive feedback, eg. the RAR RARE. In the present work we found that in several epithelial cell lines, reporter constructs containing the RAR RARE linked to the HSV-tk promoter were transactivated in the presence of RA by endogenous RARs and co-transfected RAR₁ and RAR₂ isoforms, but not by RAR₁. On the contrary, this latter isoform behaved towards the RAR RARE as an inhibitor of the transactivation produced by endogenous RARs and by cotransfected RAR₁ and RAR₂. RAR₁ also behaved as an antagonist of the transactivation produced by cotransfected RXR. The natural RAR gene promoter or RAR RARE tk constructs were not activated by the endogenous receptors of normal human keratinocytes (NHK), which are known to contain predominantly RAR₁. It was, however, possible to activate to a certain extent RAR RARE-reporter constructs in NHK by co-transfecting RAR₁, RAR₂ or RXR. The antagonist behavior of RAR₁ towards the RAR RARE may explain why in certain cell types such as keratinocytes, RAR is neither expressed nor induced by RA.Abbreviations DMEM Dulbecco's modified Eagle medium - DMSO dimethyl sulfoxide - FCS fetal calf serum - MEM minimal Eagle medium - NHK normal human keratinocyte - RA retinoic acid - RAR retinoic acid receptor - RARE retinoic acid responsive element - TRE thyroid responsive element - VDRE vitamin D response element - RXR retinoid X receptor     

MHC class II sequences of an HLA-DR2 narcoleptic

Narcolepsy has a 98% association with the DR2-Dw2/DQw1 haplotype. To establish if a disease-specific allele is present in narcolepsy, a cDNA library was made from a B-cell line from a DR2,4/DQw1,3 narcoleptic. Clones encoding the two expressed DR2 chains, along with DQw1 and chains, were isolated and completely sequenced. The coding regions of these four genes were similar to published nucleotide and protein sequences from corresponding healthy controls, with some minor exceptions. The 3 untranslated region of one of the DR2 genes in the narcoleptic was extended by 42 bp. Complete sequences were not available for DQw1.2 or from healthy individuals, but first domain nucleotide sequences showed only a single nonproductive difference in DQ. Partial protein sequences of both DQ and from published data were identical. Although the effects of minor differences cannot be ruled out completely, it is concluded that there are probably no narcolepsy-specific DR or DQ / sequences, and that the alleles found in narcolepsy are representative of those found in the healthy population.     

Degradation of 5-pregnene-3β, 20β-diol by a Nocardia sp.

Summary With growing cells of a Nocardia sp., isolated from soil, the degradation of 5-pregnene-3, 20-diol into 3-[5-oxo-7a-methyl-1 (1-hydroxo)-ethyl-3a-perhydroindane-4]-propionic acid was investigated. The results show that iron is essential for production of the perhydroindanpropionic acid, that this production is greatly enhanced by the presence of calcium and that it is maximal in the pH range 7.0–7.5.Abbreviations used in the text PD 5-pregnene-3, 20-diol (pregnendiol) - PDSA 3-[5-oxo-7a-methyl-1(1-hydroxo)-ethyl-3a-perhydroindane-4]-propionic acid (pregnendiol-secoacid) - PSA 3-[5-oxo-7a-methyl-1-acetyl-3a-perhydroindane-4]-propionic acid (progesterone-secoacid) - EDTA Ethylendiamintetracetic acid - DMSO Dimethylsulfoxide