Polymorphism of the HLA DR1 haplotype in the Israeli population investigated at the serological,cellular, and genomic levels

In the present report, we used serological, cellular, and restriction fragment length polymorphism (RFLP) to investigate the DR1 haplotype in the Israeli population. We describe an Israeli homozygous typing cell (HTC), HLA-DwLVA, which defines a new lymphocyte-activating determinant associated with Bw65, DR1 and distinct from Dwl. The parents of this donor, non-Ashkenazi Algerian Jews, are first cousins and share HLA-Cw8, Bw65, BfS, DR1, DQw1, DPw4. No specificity could be assigned to HLA-DwLVA using the 91 Ninth Workshop HTCs. Two families and forty unrelated DR1 individuals were studied with DwLVA and a panel of DR1/Dw1 HTCs. HLA-DwLVA showed segregation as a single determinant within families. This new specificity was present in 24 out of 40 (60%) unrelated DR1 individuals, indicating that in the Israeli population DwLVA is the main lymphocyte-defined determinant associated with the serologically defined DRI specificity, in contrast to non-Jewish Caucasoids where DR1 is significantly associated with Dw1. The vast majority of DwLVA-positive carriers were also Bw65 carriers, indicating that Bw65, DR1, DwLVA may represent a typical allele combination in the Israeli population. The RFLP analysis established the correlation of certain RFLPs with Dw1 and DwLVA. In addition, we describe a cluster of RFLPs that may correspond to a new Dw subtype associated with DR1, for which no serological and cellular reagents have been described so far.     

Aflatoxin influences on seed germination and root elongation by two cultivars of Glycine max and uptake of 65 Zn-ZnCl2 by the cultivars

Maximum inhibition of Glycine max, cv. Essex seed germination occurred at 10 g/ml following 72 hr imbibition in constant light. Seeds imbided 108 hr in constant darkness at this concentration showed a 20% rise in germination over that of the control. Imbibition of G. max, cv. Williams seeds in either light or dark for 96 hr did not suppress germination. Imbibition of Essex seeds in either light or dark at 2.5 through 10 g/ml stimulated root elongation except for 10 g/ml at 96 hr (light). Maximum inhibition of Williams root elongation under constant light was at 48 and 72 hr with 10 g/ml. Statistically significant differences in cotyledon, leaf and stem lengths between non-treated (NT) and treated (T) seedlings were not found except for Williams stem length at 2.5 / ml. Root elongation was stimulated 1.2- and 1.1-folds, respectively, at 5.0 (Essex) and 2.5 (Williams) g/ml. Toxin at 2.5 through 10.0 g/ml did not markedly alter either cotyledon or leaf widths with the exception of Williams leaf width at 2.5 g/ml. Medium supplementation with 2.5 through 10.0 g/ml resulted in cotyledon, leaf and root weight enhancements for Essex seedlings. Stem weight was not markedly affected. An 18% rise in Williams cotyledon weight above that of the control was seen at 2.5 g/ml. Williams leaf weights were increased 1.75- and 1.25-folds, respectively, at 2.5 and 10.0 g/ml. Aflatoxin B₁, at 2.5 g/ml promoted Williams stem and root elongation 1.20- and 1.09-folds, respectively. Most of the radioactivity from ⁶⁵Zn-ZnCl₂ recovered within organs was found within Essex roots for both T and NT seedlings. A higher amount of radioactivity was recovered within roots at each toxin concentration than was without toxin. However, this was not statistically significant. Significant differences in the distribution of radioactivity within roots between NT and T Williams seedlings were not observed. Generally, AFB₁ failed to affect significantly these two varieties of soybeans based on the tests relating to germination, growth and radiolabel uptake.     

Unusual antiproliferative effects of transforming growth factors-β 1 andβ 2 against primary cells from human tumors

Transforming growth factors 1 and2 (TGF-1 and2), tested in a clonogenic assay against primary cells from human tumors, suppress proliferation to different extents. In nineteen of twenty-six cell cultures, proliferation was < 50% of control with factor at 0.04 or 0.4 nM. Of these, TGF- 2 was more active than TGF-1 in fourteen; and TGF-1 was more active than TGF-2 in five. In seven of the nineteen, proliferation was 0% with one or the other factor. In contrast, cisplatin was much less effective in inhibiting proliferation of some of the same cells even at 1,000 or more times the molar concentration of the factors. Surprisingly, when TGF- 1 and TGF-2 were combined at equal concentrations, the antiproliferative effect of one was cancelled or markedly inhibited by the other.     

Short- and long-term effects of ACTH on the adrenal zona glomerulosa of the rat

Summary Short-term ACTH treatment provoked a decrease in volume of the lipid-droplet compartment in rat zona glomerulosa cells, and a rise in plasma and intracellular concentrations of corticosterone and aldosterone. It enhanced activities of 3-hydroxysteroid dehydrogenase (3HSD), 11-hydroxylase (11OH) and 18-hydroxylase (18OH). Long-term ACTH administration produced a hypertrophy of the zona glomerulosa and its parenchymal cells, a result of the increase in volume of the smooth endoplasmic reticulum and the mitochondrial compartment. The surface area per cell of mitochondrial inner membranes increased; the tubular cristae were transformed into a homogeneous population of vesicles. The plasma and intracellular concentrations of corticosterone further increased, whereas those of aldosterone fell below basal levels (the aldosterone-escape phenomenon). The activities of 3HSD and 11OH were enhanced, that of 180H decreased. Therefore, ACTH stimulates zona glomerulosa growth and transforms parenchymal elements into zona fasciculata celltypes. Cyanoketone nullified acute ACTH effects on plasma and intracellular concentrations of corticosterone and aldosterone, but did not affect the activities of 11OH and 18OH. Chronic ACTH treatment produced similar results, although 18OH activity was not suppressed. The mechanism underlying the aldosterone-escape phenomenon may thus involve a rise in the intracellular concentration of corticosterone, caused by the enhanced synthesis and activation of 3HSD and 11OH.     

Long Range Force between Pre-Replication Complexes (Pre-RC) in DNA Controls Replication and Cell Cycle Progression

A nonstationary interaction, that controls DNA replication and the cell cycle, is derived from a manybody physics model in a chemically open T cell. The model predicts a long range force F()=-(/2) (1-)(2-) between the pre-replication complexes (pre-RCs) bound by DNA, =/N being the relative displacement of preRCs, the number of pre-RCs, N the threshold for initiation, and the compressibility modulus in thelattice of pre-RCs which behaves like an elastically braced string. Initiation of DNA replication is induced by a switch of sign of F(), from attraction (-)and assembly in the G ₁ phase (0 < < N), to repulsion (+) and partialdisassembly in the S phase (N < < 2N), with release of licensing factors from the pre-RCs, thus explaining prevention of re-replication. Replication is terminated by a switch of sign of F at = 2N, when all primed replicons are duplicated once, and F(0)=0 corresponds to a resting cell in absence of driving force at = 0. The switch of sign of force at = N also explains the dynamic instability in growing microtubules (MTs), as well as switch in the interleukin-2 (IL2) interaction with its receptor in late G ₁, at the restriction point. Shape, slope and scale of the response curves derived agree well with experimental data from dividing T cells and polymerizing MTs, the variable length of which is due to anonlinear dependence of the growth amplitude on the initial concentrations of tubulin dimers and guanosine-tri-phosphate (GTP).     

Interaction of cytochrome c L with methanol dehydrogenase from Methylophaga marina 42:

The reaction of methanol dehydrogenase with cytochrome c _L from Methylophaga marina and the reactions of the non-physiological substrates, Wurster's blue and ascorbic acid, with both proteins were studied as a function of temperature (4–32 °C), pressure (1–2000 bar) and ionic strength using the optical high pressure stopped-flow method. The thermodynamic parameters H, S and V were determined for all reactions where electron transfers are involved. These data allowed the determination of the Maxwell relationships which proved the internal thermodynamic consistency of the system under study. A conformational change on the cytochrome c _L level was deduced from both breaks in the Arrhenius plots and the variation of the V with temperature.Abbreviations MOPS 4-morpholinepropanesulfonic acid - CHES 2-(cyclohexylamino)ethanesulfonic acid - MDH methanol dehydrogenase - EDTA ethylenedinitrilotetraacetic acid disodium salt - BTB bromothymol blue (3,3-dibromothymolsulfoneph-thalein) - PQQ 2,7,9-tricarboxy-lH-pyrrolo-[2,3f]quinoline-4,5-dione - cytochrome c _HH mammalian horse heart cytochrome c     

Charles Darwin's theory of evolution: A review of our present understanding

The paper characterizes Darwin's theory, providing a synthesis of recent historical investigations in this area. Darwin's reading of Malthus led him to appreciate the importance of population pressures, and subsequently of natural selection, with the help of the wedge metaphor. But, in itself, natural selection did not furnish an adequate account of the origin of species, for which a principle of divergence was needed. Initially, Darwin attributed this to geographical isolation, but later, following his work on barnacles which underscored the significance of variation, and arising from his work on botanical arithmetic, he supposed that diversity allowed more places to be occupied in a given region. So isolation was not regarded as essential. Large regions with intense competition, and with ample variation spread by blending, would facilitate speciation. The notion of place was different from niche, and it is questioned whether Darwin's views on ecology were as modern as is commonly supposed. Two notions of struggle are found in Darwin's theory; and three notions of variation. Criticisms of his theory led him to emphasize the importance of variation over a range of forms. Hence the theory was populational rather than typological. The theory required a Lamarckian notion of inheritable changes initiated by the environment as a source of variation. Also, Darwin deployed a use/habit theory; and the notion of sexual selection. Selection normally acted at the level of the individual, though kin selection was possible. Group selection was hinted at for man. Darwin's thinking (and also the exposition of his theory) was generally guided by the domestic-organism analogy, which satisfied his methodological requirement of a vera causa principle.     

Kinetics of growth and lactic acid production in continuous and batch culture

Summary In a lactic acid fermentation by Streptococcus faecalis, the specific consumption rate of glucose (v) and the specific production rate of lactic acid () were represented by the following simple equations as functions of the specific growth rate (): 1/=(1/) + 1/ = (1/) + By use of data from a batch culture, these two equations were derived from enzyme kinetics of the product inhibition. These equations were successfully applied to the results of batch culture and chemostat culture. In addition, calculation of ATP yield by these equations agreed with the experimental results better than the conventional Leudeking-Piret type equation, which includes two terms associated with growth and not with growth. Correspondence to: H. Ohara     

Alterations of β-adrenoceptor-G-protein-regulated adenylyl cyclase in heart failure

Alterations of receptor-G-protein-regulated adenylyl cyclase activity have been suggested to represent an important alteration leading to contractile dysfunction in the failing human heart. Recent experiments suggest that the ₁-adrenoceptor(₁AR) density and mRNA levels are reduced, while ₂-adrenoceptors and stimulatory G-proteins are unchanged (mRNA and protein level). Functional assays demonstrated that the catalyst of the adenylyl cyclase is not different between failing and nonfailing myocardium. Inhibitory G-proteins are increased (pertussis toxin substrates, protein and mRNA) and correlate to the reduced inotropic effects of -adrenoceptor agonists and of CAMP-PDE inhibitors. Gi-coupled m-cholinoceptors and A₁-adrenergic receptors are unchanged in density and affinity. Stimulation of these receptors resulted in an unchanged antiadrenergic effect on force of contraction. In conclusion, a downregulation of ₁-AR and an increase of Gi have been observed as signal transduction alteration in failing human myocardium. These alterations are due to alterations of gene expression in the failing heart and are related to a defective regulation of force of contraction in heart failure.     

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.     

Contextualizing Images in Dreams and Daydreams

A contextualizing image (CI) is a powerful central image of a dream which appears to contextualize (provide a picture-context for) the dreamer's emotion. For instance, dreamers who have experienced any serious traumatic event sometimes dream, I was overwhelmed by a tidal wave. This appears to picture their feeling of terror and/or vulnerability.A scoring system for CIs is examined here and is applied to dreams and daydreams supplied by 40 students. Two raters scoring dreams on a blind basis showed good inter-rater reliability. Recent dreams were shown to have more as well as more intense CIs than recent daydreams; likewise, dreams that stand out had more intense CIs than daydreams that stand out. Students with thin boundaries had more and more intense CIs than students with thick boundaries in their recent dreams and nightmare, but not so clearly in dreams and nightmares that stand out. The emotions judged as contextualized by the powerful images tended towards fear/terror and helplessness/vulnerability in dreams (especially in dreams that stand out) whereas emotions contextualized by images in daydreams showed a wide range with no clusters.     

Reactivity pattern of 15 HLA-Dw1 homozygous typing cells in primary mixed lymphocyte culture

Summary The Dwl specificity was highly correlated with the serologically determined HLA-DR1 antigen in the Eighth International Histocompatibility Workshop 1980. By testing a large number of HLA-Dwl, DR1 defined homozygous typing cells (HTC) in a checkerboard primary mixed lymphocyte reaction, on a panel of about 30 HLA-DR1 heterozygous individuals, and in family segregation, three Dwl subtypes could be defined in association with certain HLA-A, -B, and -C-antigens. HTC TA, FRI, and FRA carrying the HLA haplotypes A11, B35, Cw4 or A3, B35, Cw4 in the homozygous state gave positive typing results with most HLA-DR1 positive panel members and stimulated only four other Dw1 HTCs (SRR35%). In contrast to this operationally broad specificity, Dw1-HTC-HEN (HLA-A2, B44, C-, homozygous) was non-stimulatory to all HTCs except one, but gave high responses against these, leading to the definition of a narrow specificity included in the broad one. Another such narrow specificity was represented by HTC FEE (HLA-A2, B27, Cw2 homozygous). Typing patterns with FEE were mostly different from those defined with other HTC. In family studies a specific typing pattern for this HTC could be shown to segregate with HLA. However, within some of these responses a contribution of the HLA haplotype in the trans position must be assumed.Supported in part by DFG grant Ri 164/14     

Pesticides and heavy metals in Danish streambed sediment

The role of streambed sediment as a sink for pesticides and heavy metals was investigated in 30 Danish lowland streams. The investigated streams drain catchments varying in hydrology, topography, soil type and land use. The <250 m newly accumulated fraction of the uppermost 1–2 cm layer of streambed sediment was analysed for 19 old and modern pesticides and 9 heavy metals. DDE was present in the sediment of all the streams. Of the herbicides, fungicides and insecticides currently in use, the most frequently detected was diuron (50.0%), fenpropimorph (66.7%) and lambda-cyhalothrin (6.7%), respectively. The pesticides detected in the highest concentration were fenpropimorph (1700 ng g^–1), propiconazole (130 ng g^–1) and isoproturon (110 ng g^–1). The heavy metals are listed in order of increasing median concentration: Cd (0.80 g g^–1), Co (9.1 g g^–1), As (12.0 g g^–1), Ni (19.0 g g^–1), Cr (19.2 g g^–1), Pb (19.7 g g^–1), Cu (20.1 g g^–1), V (28.5 g g^–1), Zn (103 g g^–1). The average number of pesticides detected in the 27 streams draining predominantly agricultural catchments was (3.7±2.0) being higher (p=0.077) than in the three streams draining non-agricultural catchments (1.7±0.6). Pesticides were significantly related to catchment size, soil type and hydrological regime. Several heavy metals (Cr, Cu, Pb, V and Zn) were related to urban activity and soil type.     

Evidence for the direct involvement ofβ-hemolysin inAeromonas hydrophila enteropathogenicity

Culture filtrates of 19 of 21 (90%) -hemolytic isolates ofAeromonas hydrophila caused fluid accumulation in permanently ligated rabbit ileal loops, whereas no fluid was accumulated with filtrates of eight non--hemolytic isolates. Antiserum to purified -hemolysin neutralized the ileal loop activity of culture filtrates from four of four -hemolytic isolates, and treatment at 56°C for 10 min eliminated the loop activity of six additional isolates. These results support the conclusion that -hemolysin alone causes significant changes in intestinal permeability and that it is a more common pathogenic mechanism than the heat-stable cytotonic enterotoxin. Electrophoretic and serological assays showed evidence for production of only one species of -hemolysin byA. hydrophila.     

Age-related accumulation of lysosomes and other cytological features in active thyroid follicles of the CBA mouse

Summary This study attempts to elucidate the mechanism through which lysosomal accumulation occurs with age in the epithelial cells of the thyroid gland and especially in the active follicles of the aging mouse thyroid. Thyroid morphology and function in old CBA (at least 24 months of age) male mice were compared with those in young (2 months of age) animals. The effects of different intake of iodine were tested and compared in both cohorts, each of which was divided into three groups: (i) low iodine group, (ii) moderate iodine group, and (iii) high iodine group. As expected, the present work confirmed the well-known accumulation with age of cold follicles coexisting with active follicles in the old mouse thyroid. Attention has been focused on the active follicles whose follicular cells contained in their cytoplasm a large number of pleomorphic dense bodies. The lysosomal nature of these bodies, referred to as secondary lysosomes, was confirmed by histochemistry; however, they displayed variability in acid phosphatase staining. In old animals, regardless of the type of iodine regimen, the ratio between relative follicular volume and relative colloid volume as determined by morphometry remained unchanged. Ultrastructurally, the relative volume occupied by secondary lysosomes in active follicles was always higher than in the young groups. Autoradiographic studies with ¹²⁵I revealed that a large part of the radioactivity was located in secondary lysosomes of thyroid cells in active follicels of old mice when radioiodine was injected 3 weeks before death. Two different types of vacuoles were present in a non-negligible number of thyrocytes of the active follicles in aged cohorts. The first type was made up of grossly dilated rough endoplasmic cisternae, the second corresponded to intracytoplasmic microfollicular vacuoles. Both aspects have been described in conditions of chronic stimulation. It is concluded (1) that different intake of iodine for 6 weeks does not modulate the thyroid morphology in old mice; (2) that in the thyrocytes of the active follicles in old mice accumulation of secondary lysosomes occurs due to a slowdown of turnover; and (3) that the follicular cells of active follicles feature morphological aspects suggesting a hyperactive state compensating the lack of hormone production in the cold follicles.     

Zur Feinstruktur von Cuticula und Epidermis beim Flußkrebs Orconectes limosus während eines Häutungszyklus

Zusammenfassung Die Cuticula an der Innen- und Außenseite der Branchiostegite des Flußkrebses besteht wie für Arthropoden üblich aus Epi- und Procuticula. Sowohl die Epicuticula als auch die Procuticula von Innen- und Außenseite unterscheiden sich im Feinbau wesentlich voneinander. An der Innenseite ist die Epicuticula einfach gebaut; Die Procuticula ist lamelliert und zeigt meist die bogenförmigen Muster von Mikrofibrillen. Die Epicuticula an der Außenseite weist in den in dieser Arbeit untersuchten Entwicklungsstadien einen sehr viel komplizierteren Feinbau auf, der in der Entwicklung gewissen Änderungen unterliegt. In der wiederum lamellierten Procuticula an der Außenseite sind die Mikrofibrillen zu Balken gebündelt. Die Ausrichtung der Mikrofibrillen dreht sich innerhalb einer Lamelle um 180°. Durch die Procuticula ziehen Fortsätze der Epidermiszellen, außerdem Stäbe der sog. Verbindungsstrukturen.Die Bildung der Cuticula an der Innenseite konnte weitgehend vollständig verfolgt werden; sie ist gut mit der Bildung der Cuticula bei verschiedenen Insekten vergleichbar.Die Bildung der Cuticula an der Außenseite konnte dagegen nur von Beginn der Abscheidung der Proouticula bis zur Häutung verfolgt werden. Kurz vor Beginn der Cuticulaabscheidung kommt es in den Epidermiszellen zu einer stärkeren Entwicklung des rauhen ER. Während der gesamten von uns verfolgten Bildungsstadien sieht man Vesikel mit dichtem Inhalt besonders in der Nähe des Zellapex. Sie geben anscheinend hier ihren Inhalt, Cuticulamaterial, nach außen ab. Sie stammen wohl aus Golgibereichen. Auch Stachelsaumbläschen (coated vesicles) kommen regelmäßig vor, deren genetischer Zusammenhang mit multivesikulären Körpern diskutiert wird. Bei der Abscheidung der fibrillären Cuticulasubstanzen spielen besondere Differenzierungen der Zell oberfläche, — kappenartige Verdichtungen der Zelloberfläche, meist an der Spitze kleiner Mikrovilli — eine wesentliche Rolle.

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The ultrastructure of cuticle and epidermis in the crayfish Crconectes limosus during a moulting cycle

Summary The cuticle of the inside and outside of the branchiostegites of the crayfish consists of an epicuticle and a procuticle — as common in arthropods. Concerning their ultrastructure epicuticle and procuticle differ essentially from each other on both the inside as well as the outside. On the inside the epicuticle is built plainly; the procuticle is laminated, and, mostly it shows the arched patterns of microfibrils. In those developmental stages investigated in this project the epicuticle of the outside shows a much more intricated ultrastructure, since during formation it is subject to certain changes. On the outside the procuticle is also laminated; the microfibrils are bundled up to bars. The alignment of those microfibrils within one lamella is twisted for 180°. The procuticle is penetrated by processes of epidermal cells and by rods of the so-called connecting structures.The formation of the cuticle on the inside was observed completely; it is comparable to the forming of the cuticle in several insects. However, the formation of the cuticle on the outside was only observed from the beginning of the procuticular development up to the moulting.Shortly before formation of the cuticle the development of rough ER in the epidermal cells seems to be intensified. In all of developmental stages observed there appear vesicles with dense contents mainly situated nearby the cell apex. At this site they evidently deliver their contents — cuticular materials — to the outside of the cell; they probably originate in the Golgi areas. There occur coated vesicles regularity, too; their genetic relation to multivesicular bodies is discussed. Special differentiation on the cell surface i.e. dome-like consolidations of the cell surface mainly placed at the tip of small microvilli are of great importance for the secretion of the cuticle substances.

     

Lipochemistry of the progamic stage of a self-incompatible species: Neutral lipids and fatty acids of the secretory stigma during its glandular activity,and of the solid style,the ovary and the anther in Forsythia intermedia Zab. (Heterostylic species)

Chromatographic (thin-layer, gas column, column chromatography) analyses of neutral lipids and fatty acids of reproductive tissues of Forsythia intermedia Zab., a self-incompatible species, were performed with two objectives in mind: 1. To determine whether there is a qualitative evolution of the different classes of lipids and fatty acids that could be correlated with the three functional stages observed during previous histochemical and ultrastructural studies. The stigmatic exudate and intracellular accumulations consist mainly of neutral lipids. 2. To compare the lipid composition of the stigma (both thrum and pin forms) with that of the style, the ovary, and the anther, and to investigate the possible existence of a stigma-specific lipid compound. Stigmatic neutral lipids are found mostly in a glyceridic mixture probably containing hydrocarbons and terpenes. The fatty acids identified are between C:7 and C: 12, with the maximum unsaturated form being a C: 18. During the secretory process there is no great qualitative diference between the neutral lipids and fatty acids found in the stigmas of thrum and pin forms. Sterols are present in styles, ovaries, and anthers, but not in stigmas. They represent the only difference in the lipid composition of these various floral structures.     

Zum Nachweis tritiierter Assimilate in den Siebröhren von Cucurbita

Summary After application of D-glucose-6-T to small areas of leaf surfaces of Cucurbita, radioactivity — mainly sucrose-T — could exclusively be localized by histoautoradiography (dry-technique) within single sieve tubes of exporting bundles. The centre of activity corresponded to the slime-plugs (in crosssection-autoradiograms) of the sieve tubes and to the sieve plates (in longitudinal sections). It is concluded that only the sieve tubes are the conducting channels for the long-distance transport of those substances which are labeled with tritium in these experiments.     

Nuclear behavior in multinucleate Schizophyllum commune germlings

Summary The ultrastructure of a fir morphological mutant containing multinucleate cells is described in Schizophyllum commune. The germlings of basidiospores which arose from mating fir with wild-type mycelium were studied in culture by phase contrast microscopy to elucidate behavior of multinucleate cells. Nuclear division appeared synchronous from two nuclei yielding four progeny through six nuclei producing twelve products, beyond which loss of synchrony was indicated. Compensatory nuclear migration into an anucleate cell was presumed during synchronous division of nuclear aggregates in the adjacent cell of an individual germling. The migrant nucleus eventually returned to the cell of origin. However, the return route was not via the central pore of the septum but rather occurred at the juncture of the cross-wall with the germling-periphery. Ultrastructure of a partial septum in fir which could accommodate nuclear passage of this sort is described.