Adoptions expérimentales de larves entre des fourmis de genres différents (II):Myrmica laevinodis Nylander etAnergates atratulus Schenck

Résumé Nous avons fait élever des larves d'Anergates atratulus par des ouvrières deMyrmica laevinodis à 22°C. Pour y parvenir, il n'est pas utile de faire hivernerensemble les larves d'Anergates et les ouvrières deMyrmica. La présence de larves autochtones n'empêche pas lesMyrmica d'élever des larves d'Anergates. Dans toutes les expériences lesMyrmica ont été soumises au fridavant de recevoir des larves d'Anergates. Aucune reine deMyrmica n'a été utilisée dans ces expériences.Sur les 64 larves d'Anergates que nous avons utilisées, 38 se sont transformées en imagos. C'est au début de l'adoption et au moment des métamorphoses que périrent la plupart des 26Anergates perdus. Les femelles vécurent en général 2 ou 3 jours et cherchèrent très tôt à quitter le nid natal. Les mâles vécurent 2 à 3 semaines.

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Summary Larvae ofAnergates atratulus were experimentally reared by workers ofMyrmica laevinodis, at 22°C. An overwintering of both larvae ofAnergates and workers ofMyrmica is not necessary for the success of that experiment. The presence of larvae ofMyrmica does not keep theMyrmica from rearing larvae ofAnergates. The workers ofMyrmica have been cooled, in all the experiments, before receiving larvae ofAnergates. No queen ofMyrmica have been used in that experiments.38 of the 64 larvae ofAnergates used became imagos. Most of the 26 lostAnergates died at the beginning of the adoption and during the metamorphosis. The females lived generally 2 or 3 days and tried, very early, to leave their native nest. The males lived 2 or 3 weeks.

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Anergates atratulus Myrmica laevinodis, 22 . bmecme Anergates Myrmica. Myrmica Anergates. Myrmica Anergates. Myrmica . 64 Anergates , 38 . 26 Anergates 2 3 . 2 3 .

     

UDP-GlcNAc: Galβ3GalNAc-Mucin: (GlcNAc → GalNAc) β6-N-Acetylglucosaminyltransferase and UDP-GlcNAc: Galβ3(GlcNAcβ6) GalNAc-Mucin (GlcNAc → Gal)β3-N-Acetylglucosaminyltransferase from Swine Trachea Epithelium

Summary Two specific -N-acetylglucosaminyltransferases involved in the branching and elongation of mucin oligosaccharide chains, namely, a 1,6 N-acetylglucosaminylsaminyltransferase that transfers N-acetylglucosamine from UDP-N-acetylglucosamine to Gal3GalNAc-Mucin to yield Gal3(GlcNAc6)GalNAc-Mucin and a 3-N-acetylglucosaminyl transferase that transfers N-acetylglucosamine from UDP-N-acetylglucosamine to Gal3(GlcNAC6)GalNAc-mucin to yield GlcNAc3Gal3 (GlcNAc6)GalNAc-Mucin were purified from the microsomal fraction of swine trachea epithelium. The 1,6-N-acetylglucosaminyltransferase was purified about 21,800-fold by procedures which included affinity chromatography on DEAE columns containing bound asialo Cowper's gland mucin glycoprotein with Gal1,3GalNAc side chains. The apparent molecular weight estimated by gel filtration was found to be about 60 Kd. The purified enzyme showed a high specificity for Gal1,3GalNAc chains and the most active substrates were mucin glycoproteins containing these chains. The apparent Km of the 6-glucosaminyltrans-ferase for Cowper's gland mucin glycoprotein containing Gal1,3GalNAc chains was 0.53 µM; for UDP-N-acetylglucosamine, 12 µM; and for Gal 1,3GalNAc NO₂ø, 4 mM. The activity of the 6-glucosaminyltransferase was dependent on the extent of glycosylation of the Gal3GalNAc chains in Cowper's gland mucin glycoprotein.The best substrate for the partially purified 3-Glucosaminyltransferase was Cowper's gland mucin glycoprotein containing Gal1,3(GlcNAc6)GalNAc side chains. This enzyme showed little or no activity with intact sialylated Cowper's gland mucin glycoprotein or derivatives of this glycoprotein containing GalNAc or Gal1,3GalNAc side chains.The radioactive oligosaccharides formed by these enzymes in large scale reaction mixtures were released from the mucin glycoproteins by treatment with alkaline borohydride, isolated by gel filtration on Bio-Gel P-6 and characterized by methylation analysis and sequential digestion with exoglycosidases. The oligosaccharide products formed by the 6- and 3-glucosaminyltransferases were shown to be Gal3(GlcNAC6) GalNAc and GlcNAc3 Gal3(GlcNAC6)GalNAc respectively.Taken collectively, these results demonstrate that swine trachea epithelium contains two specific N-acetylglucosaminyltransferases which catalyze the initial branching and elongation reactions involved in the synthesis of O-linked oligosaccharide chains in respiratory mucin glycoproteins. The first enzyme a 6-glucosaminyltransferase converts Gal3GalNAc chains in mucin glycoproteins to Gal3(GlcNAc6)GalNAc chains. This product is the substrate for a second 3-glucosaminyltransferase which converts the Gal3(GlcNAc6)GalNAc chains to GlcNAc3Gal(GlcNAc6)GalNAc chains in the glycoprotein. The 3-glucosaminyltransferase did not utilize Gal3GalNAc chains as a substrate and this results in an ordered sequence of addition of N-acetylglucosamine residues to growing oligosaccharide chains in tracheal mucin glycoproteins.Abbreviations NeuNAc N-acetylneuraminic acid - GalNAcol N-acetylgalactosaminitol - CGMG Cowper's gland mucin glycoprotein - GalNAc-CGMG Cowper's gland mucin glycoprotein containing GalNAc side chains O-glycosidically linked to serine or threonine - Gal3GalNAc-CGMC Cowper's gland mucin glycoprotein containing Gal3GalNAc side chains - MES 2-(N-morpholino) Ethane Sulfonic acid - PBS Phosphate Buffered Saline     

The sialyl-α2,6-lactosaminyl-structure: Biosynthesis and functional role

Sialylation represents one of the most frequently occurring terminations of the oligosaccharide chains of glycoproteins and glycolipids. Sialic acid is commonly found ,3- or ,6-linked to galactose (Gal), ,6-linked to N-acetylgalactosamine (GalNAc) or ,8-linked to another sialic acid. The biosynthesis of the various linkages is mediated by the different members of the sialyltransferase family. The addition of sialic acid in ,6-linkage to the galactose residue of lactosamine (type 2 chains) is catalyzed by -galactoside ,6-sialyltransferase (ST6Gal.I). Although expressed by a single gene, this enzyme shows a complex pattern of regulation which allows its tissue- and stage-specific modulation. The cognate oligosaccharide structure, NeuAc,6Gal1,4GIcNAc, is widely distributed among tissues and is involved in biological processes such as the regulation of the immune response and the progression of colon cancer. This review summarizes the current knowledge on the biochemistry of ST6Gal.I and on the functional role of the sialyl-,6-lactosaminyl structure.     

An explication of ‘wind illness’ in Northern Thailand

Wind illness is a very common complaint among the Northern Thai, yet is rarely recognized by Thai physicians trained in biomedicine. Persons most susceptible to wind illness are adult women who have ever borne a child. Consequently, data were obtained from 415 everparous women, 43% of whom reported ever having had wind illness and 57%, never having had it. In addition, 20 individuals who had ever had the syndrome were followed for case study, and 13 indigenous healers who traditionally treat clients suffering wind illness were interviewed. Their perceptions of the etiology, symptomatology and treatment of wind illness are reported in Part I. Part II is an attempt to define wind illness in terms of biomedicine and as a consequence of fertility. Part III synthesizes the emic and etic accounts with explanations for the perdurance of wind illness despite the advances of biomedicine and the recent fertility decline in Northern Thailand.     

Contrasting effects of ACTH and cyanoketone on Δ5-3β-hydroxysteroid dehydrogenase activity in interrenal glands of tadpoles of Rana catesbeiana in vitro

Summary The present communication describes an investigation of stimulation and inhibition of ⁵-3-hydroxysteroid dehydrogenase in interrenal glands of tadpoles of Rana catesbeiana. Frozen sections of interrenal glands, together with kidneys, were prepared histochemically for assay of ⁵-3-HSD activity. Concentrations of 0.01, 0.1, 1, and 10 IU/ml of ACTH or of 0.01, 0.1, 1, and 10 g/ml of cyanoketone were added to the incubation media. The reaction products of the histochemically prepared slides, in terms of absorbance, were scanned at a defined area with a computerized microscope spectrophotometer. The results indicate that ACTH causes a significant dose-response stimulation of ⁵-3-HSD activity in tadpole interrenals; cyanoketone, on the other hand, causes significant dose-dependent inhibition.     

Dynamics of the cytoskeleton of epidermal cells in situ and in culture

Summary The cytoskeleton of primary tissue-culture cells from the epidermis of Xenopus laevis tadpoles was investigated by phase-contrast, immunofluorescence, and electron microscopy. The connection between the arrangement of different types of filaments and the mechanical properties of the epidermis is discussed. The bilayered epidermis attains stability from thick bundles of tonofilaments interconnecting the basal desmosomes. Twisting of tonofilaments around each other can explain the occurrence of elastic filamentous curls forming a meshwork braced between rows of small desmosomes in the apical region of the epidermis. Actin is arranged as a diffuse meshwork and sometimes forms bundles intermingling with tonofilament bundles. Surface membranes and rows of small desmosomes are delineated by actin and contain -actinin. Actin raises the tension for rounding and spreading of cells. Microtubules stabilize already well-developed lamellae.     

Modeling the acquisition of counting with an associative network

In the acquision of counting by children, there are three interesting phenomena (Fuson et al. 1982): (1) the number word sequence produced by children can be divided into three distinct portions, called the conventional, stable nonconventional, and unstable portions; (2) irregular number words such as fifteen are omitted more often than regular ones such as fourteen, sixteen, and seventeen; and (3) initially the number word sequence is in a recitation form, rather than in the form of an associative chain of separable serial elements. Our paper at first analyzes these phenomena from the viewpoint of associative memory by assuming the number word sequences are made up of many associative relationships between the number words. This assumption is not contradictory to the third phenomenon described above, because the associative relationships are not confined only to those between the serial number words. On the basis of these anaylses, an associative network model, HAPS proposed by one of the authors (Hirai 1983), is extended so that it can mimic some aspects of the learning of sequence which involves the above three phenomena. The learning and production of sequence by the network are simulated on a digital computer, and the results show that the three phenomena can be observed in the performance of the network.     

Erratum: Cloning and sequencing of the phycocyanin gene from Spirulina maxima and its evolutionary analysis

The genes were cloned for the two apoprotein subunits, and ,of phycocyanin from the cyanobacterium Spirulina maxima = Arthrospiramaxima) strain F3. The - and -subunit gene-coding regionscontain 489 bp and 519 bp, respectively. The -subunit gene is upstreamfrom the -subunit gene, with a 111-bp segment separating them.Similarities between the -subunits of S. maxima and nine othercyanobacteria were between 58% and 99%, as were those between the -subunits. The maximum similarity between the - and -subunits from S. maxima was 27%.     

Gross nitrogen transformations in soils from uncut and cut boreal upland and peatland coniferous forest stands

Gross and net nitrogen (N) ammonification and nitrification were measured in soils from an uncut and recently cut upland and peatland conifer stand in northwestern Ontario, Canada. Rates of gross total inorganic N immobilization were similar to gross mineralization, resulting in low net mineralization rates in soils from all four upland and peatland conifer stands. Gross ammonification rates were variable but similar in soils from uncut and cut peatland hollows (18–19mgNkg^–1day^–1) and upland forest floor soils (14–19mgNkg^–1day^–1). Gross ammonium ( ) immobilization rates were also variable but similar to ammonification rates. Median gross nitrification rates were within 0–2mgNkg^–1day^–1 in soils from all four upland and peatland cut and uncut stands, although rates were consistently higher for the soils from the cut stands. Large variability in gross nitrification rates were observed in peatland soils, however the highest gross nitrification rates were measured in saturated peatland soils. Net rates remained low in the soils from all four stands due to high nitrate ( ) immobilization and very fast turnover (<0.2 day). Our results suggest that potential losses may be negated by high immobilization in uncut and cut boreal forest stands. This study reveals the potential for the interaction of N production and consumption processes in regulating N retention in upland and peatland conifer forests, and the resilience of the boreal forest to disturbance.     

A structural model for elongation factor 1 (EF-1) and phosphorylation by protein kinase CKII

EF-1a binds aminoacyl-tRNA to the ribosome with the hydrolysis of GTP; the complex facilitates the exchange of GDP for GTP to initiate another round of elongation. To examine the subunit structure of EF-1 and phosphorylation by protein kinase CKII, recombinant , , and subunits from rabbit were expressed in E. coli and the subunits were reconstituted into partial and complete complexes and analyzed by gel filtration. To determine the availability of the and subunits for phosphorylation by CKII, the subunits and the reconstituted complexes were examined as substrates for CKII. Formation of the nucleotide exchange complex increased the rate of phosphorylation of the subunit and reduced the Km, while addition of to or the complex inhibited phosphorylation by CKII. However, a had little effect on phosphorylation of . Thus, the and subunits in EF-1 were differentially phosphorylated by CKII, in that phosphorylation of was altered by association with other subunits, while the site on was always available for phosphorylation by CKII. From the availability of the subunits for phosphorylation by CKII and the composition of the reconstituted partial and complete complexes, a model for the subunit structure of EF-1 consisting of (22)2 is proposed and discussed.     

Physiological relationship between the temperate phages lambda and phi80

Summary This work deals with the ability of phage 80 to provide defective mutants of with their missing functions. Functions Involved in Recombination. As shown by others, the Int mechanism of 80 cannot excise prophage . However, 80 efficiently excises recombinants from tandem dilysogens, using its Ter mechanism. Likewise, the nonspecific mechanism Red is interchangeable between 80 and . Maturation of DNA by 80. The Ter recombinants excised by 80 from tandem dilysogens are packaged into a 80 protein coat. This contrasts with the fact, already mentionned by Dove, that 80 is extremely inefficient for packaging phage superinfecting a -lysogen. The latter result is also found when the helper phage is a hybrid with the left arm of (80hy4 or 80hy41 — see Fig. 1). However, the maturation of the superinfecting is much more efficient if the 80hy used as a helper has the att-N region of (like 80hy1). Conversely a with the att-N region of 80 (hy6 — see Fig. 1) is packaged more efficiently by 80 or 80hy4 than by 80hy1. It is suggested that the maturation of chromosome superinfecting an immune cell requires a recombination with the helper phage. Vegetative Functions. Among the replicative functoons O and P, the latter only can be supplied by 80. That N mutants are efficiently helped by 80 does not tell that 80 provides the defective with an active N product; the chromosomes are simply packaged into a 80 coat. This shows that 80 is unable to switch on the late genes of . That neither 80 nor any of the 80hy tested can provide an active N product is shown in a more direct way by their complete failure to help N ^-r₁₄; this phage carries a polar mutation which makes the expression of genes O and P entirely N-dependant. The maturation of a N ^- by 80 contrasts with the fact that mutants affected in late genes (A, F or H) are not efficiently helped by 80. This suggests that the products coded by these genes are not interchangeable between 80 and , and that packaging of DNA into 80 coats is possible but inhibited when late proteins are present in the cell. Activation of the Late Genes. Among the im ₈₀ h ⁺ hybrids tested, only 80hy41 is able to switch on the late genes of a N defective mutant. This hybrid differs from the other hybrids studied here, by the fact that it has the Q-S-R region of (see Fig. 1). The results are consistant with the view that the product of Q gene is sufficient for activating the late genes of a DNA. N would thus control the expression of late genes only indirectly by controlling the expression of gene Q (Couturier & Dambly have independantly reached the same conclusion, 1970). Furthermore the failure of 80 and of the 80hy1 and 80hy4 to activate the late genes of would imply that these phages are unable to provide an Q product active on the chromosome Reciprocally, switches on the late genes of prophage 80hy41, but not of prophages 80hy1 and 80hy4. This suggests that the initiation of late genes expression takes place at a main specific site located in the Q-S-R region of the chromosome. The expression of the late genes would thus be sequential, and proceed through the left arm only when steaky ends cohere. Similar conclusions were reached independantly by Toussaint (1969) and by Herskowitz and Signer (1970).

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Ce travail a été réalisé dans le cadre du contrat d'association Euratom-U. L. B. 007-61-10 ABIB et avec l'aide du Fonds de la Recherche Fondamentale Collective.     

Inhibition of protein synthesis enhances the lytic effects of tumor necrosis factor α and interferon γ in cell lines derived from gynecological malignancies

Summary Few clinical responses have occurred in preliminary studies using the cytokines tumor necrosis factor (TNF) or interferon (IFN) in cancer patients. This may be related to the observation that many malignant cell lines are resistant to lysis by these cytokinesin vitro. Resistance to lysis by TNF or IFN in many cells is controlled by a protein-synthesis-dependent mechanism, such that when protein synthesis is inhibited cells become sensitive to lysis by these cytokines. Because there is some evidence that TNF and IFN act through different lytic mechanisms and are opposed by different resistance mechanisms, we treated a panel of eight cell lines, five derived from human cervical carcinomas (ME-180, MS751, SiHa, HT-3, and C-33A) and three derived from ovarian carcinomas (Caov-3, SK-OV-3, and NIH: OVCAR-3) with both TNF and IFN to determine whether such combination treatment might maximizein vitro cell lysis. Our results showed that pretreatment with IFN followed by exposure to TNF in the presence of protein synthesis inhibitors increased lysis of seven of the eight cell lines above that seen with either TNF or IFN and inhibitors of protein synthesis. Only the cell line C-33A was resistant to lysis by TNF and IFN, when exposed to these agents both alone and in combination with protein synthesis inhibitors. Clinically, combining the cytokines TNF and IFN with protein synthesis inhibitors may maximize thein vivo lytic effects of these cytokines.Supported by American Cancer Society Career Development Award 90-221     

The composition of Erythrosins, Fluorescein, Phloxine and Rose Bengal: a study using thin-layer chromatography and solvent extraction

Synopsis Commercial samples of Erythrosin B (CI 45430), Erythrosin Y (CI 45425), Fluorescein (CI 45350), Phloxine (CI 45410) and Rose Bengal (CI 45440) have been analysed by thin-layer chromatography. The Erythrosins were found to be mixtures consisting in the main of 4-iodofluorescein, 4,5-di-iodofluorescein, 2,4,5-triiodofluorescein and 2,4,5,7-tetraiodofluorescein, in some instances together with 2,4,5-tri-iodo-4,5,6,7-tetrachlorofluorescein and 2,4,5,7-tetraiodo-4,5,6,7-tetrachlorofluorescein. Samples of Fluorescein were mixtures of the nominal dye usually with traces of several unidentified, fluorescent components. Those of Phloxine consisted mainly of mixtures of 4-bromo-4,5,6,7-tetrachlorofluorescein, 4,5-dibromo-4,5,6,7-tetrachlorofluorescein, 2,4,5-tribromo-4,5,6,7-tetrachlorofluorescein and 2,4,5,7-tetrabromo-4,5,6,7-tetrachlorofluorescein, often with 4,5,6,7-tetrachlorofluorescein Samples of Rose Bengal were mixtures of 4-iodo-4,5,6,7-tetrachlorofluorescein, 4,5-di-iodo-4,5,6,7-tetrachlorofluorescein, 2,4,5-tri-iodo-4,5,6,7-tetrachlorofluorescein and 2,4,5,7-tetraiodo-4,5,6,7-tetrachlorofluorescein together with some unidentified components.Most of the commercial dye samples gave an insoluble residue when extracted with methanol. This residue was usually inorganic carbonate or halide. Some possible practical consequences of the various impurities are discussed.     

Conservation status of parrot populations in an Atlantic rainforest area of southeastern Brazil

A census of four species of syntopic parrots was carried out using distance sampling methods on São Sebastião island, SE Brazil. Most of the 33593 ha island is covered by mature and secondary Atlantic rainforest. Almost 80% of these forests are within the Ilhabela Park. Although the species counted have marked differences in size and weight, density (individuals/km²) and estimated population size in 23500 ha of well-preserved forests were similar: Amazona farinosa (13.82±5.94; 3247±1395), Pionus maximiliani (15.79±7.04; 3712±1654), Brotogeris tirica (15.05±4.87; 3537±1143) and Pyrrhura frontalis (13.06±5.53; 3068±1298). Encounter rates of Forpus crassirostris and Pionopsitta pileata were very low, which suggests that there is only a small population of these species on the island. The São Sebastião forests still support healthy populations of parrots. Although woodpecker population estimates on the island are large enough to provide nesting sites for parrots, competition for holes with other secondary cavity nesters such as toucans, flycatchers and tytiras, and the selective cutting of dead trees for canoe construction, which is a common practice on the island, may limit hole availability for parrots.     

In vitro analysis of ion channels in periaxolemmal-myelin and white matter clathrin coated vesicles: Modulation by calcium and GTPγS

This study reports the analysis of K⁺ channel activity in bovine periaxolemmal-myelin and white matter-derived clathrin-coated vesicles. Channel activity was evaluated by the fusion of membrane vesicles with phospholipid bilayers formed across a patch-clamp pipette. In periaxolemmal myelin spontaneous K⁺ channels were observed with amplitudes of 25–30, 45–55, and 80–100 pS, all of which exhibited mean open-times of 1–2 msec. The open state probability of the 50 pS channel in periaxolemmal-myelin was increased by 6-methyldihydro-pyran-2-one. Periaxolemmal-myelin K⁺ channel activity was regulated by Ca²⁺. Little or no change in activity was observed when Ca²⁺ was added to thecis side of the bilayer. Addition of 10 M total Ca²⁺ also resulted in little change in K⁺ channel activity. However, at 80 M total Ca²⁺ all K⁺ channel activity was suppressed along with the activation of a 100 pS Cl^– channel. The K⁺ channel activity in periaxolemmal myelin was also regulated through a G-protein. Addition of GTPS to thetrans side of the bilayer resulted in a restriction of activity to the 45–50 pS channel which was present at all holding potentials. Endocytic coated vesicles, form in part through G-protein mediated events; white matter coated vesicles were analyzed for G proteins and for K⁺ channel activity. These vesicles, which previous studies had shown are derived from periaxolemmal domains, were found to be enriched in the subunits of G₀, G_s, and G_i and the low molecular weight G protein,ras. As with periaxolemmal-myelin treated with GTPS, the vesicle membrane exhibited only the 50 pS channel. The channel was active at all holding potentials and had open times of 1–6 msec. Addition of GTPS to the bilayer fused with vesicle membrane appeared to suppress this channel activity at low voltages yet induced a hyperactive state at holding potentials of 45 mV or greater. The vesicle 50 pS K⁺ channel was also activated by the 6-methyl-dihydropyron-2-one (20 M).Abbreviations CNPase 2–3 cyclic nucleotide phosphohydrolase - EDTA ethylenediamine N,N,N,N-tetraacetic acid - G-protein GTP(guanosine triphosphate) binding protein - GTPS guanosine 5-O-(3-thiotriphosphate) - MAG myelin associated glycoprotein - Na⁺ K⁺ ATPase, Na⁺ and K⁺ stimulated adenosine triphosphatase - PLP myelin proteolipid protein Special issue dedicated to Dr. Majorie B. Lees.     

Comparison of the carbohydrate moieties of recombinant soluble Fcε receptor (sFcε RII/sCD23) expressed inSaccharomyces cerevisiae and Chinese hamster ovary cells. Different O-glycosylation sites are used by yeast and mammalian cells

Recombinant human soluble low affinity receptor for the Fc portion of IgE (sFcRII/sCD23) was produced inSaccharomyces cerevisiae or Chinese hamster ovary cells and subjected to carbohydrate analysis. Applied methods included analytical SDS-PAGE, reversed phase HPLC, methylation analysis and sequential degradation with exoglycosidases. The results revealed that sFcRII derived from Chinese hamster ovary cells is glycosylated exclusively at Ser-147, containing mainly the trisaccharide Sia(2–3)Gal(1–3)GalNAc, whereas the yeast derived glycoprotein was glycosylated at Ser-167 and contained only -mannosyl residues. It is shown here for the first time that different amino acids of a given protein can be O-glycosylated when expressed in yeast or Chinese hamster ovary cells.     

Zur Dynamik feiner Pseudopodien von Hochmoor-Amöben

Zusammenfassung Es werden verschiedene Vorgänge an sehr zarten Pseudopodien beschrieben und mit Hilfe der an submikroskopischen Fibrillen (schraubig gebauten Mikrofibrillen und Mikroröhrchen der Elektronenmikroskopie) auftretenden Torsionsspannungen und Rotationen gedeutet.

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On the dynamics of slender pseudopodia of bog amebae

Summary Different processes which occur on very slender pseudopods are described. They are interpreted with the help of torsional forces and revolutions of the submicroscopic fibrils (helical microfibrils and microtubules in electron microscopy).

     

Structure of tanacetan,a pectic polysaccharide from tansy Tanacetum vulgare L

Tanacetan TVF was found to have a branched structure with a backbone of linear -1,4-D-galacturonan. The ramified regions consist of linear -1,2-L-rhamno--1,4-D-galacturonan as the core. The side chains appear to attach to the 4-position of the L-rhamnopyranose residues. They are present as single -galactopyranose residues or a branching -1,4-galactopyranan bearing 4,6-substituted -D-galactopyranose residues as branched points. In addition, the ramified regions contain side chains of a branched -1,5-arabinofuranan possessing 2,5- and 3,5-substituted -L-arabinofuranose residues as branching points. Some side chains of rhamnogalacturonan appear to be arabinogalactan which contains branched sugar chains of -1,5-arabinofuranan attached to the linear chains of -1,4-galactopyranan by 1,3- and 1,6-linkages. The residues of -L-arabinofuranose seem to occupy the terminal positions of the arabinogalactan side chains.     

Heterogeneity of the hemoglobin of the Ohrid trout (Salmo L. typicus)

We have analyzed the hemoglobins of five individual trout from the Ohrid Lake (Salmo L. typicus) by electrophoretic methods, by reversed-phase high-performance liquid chromatography, and by limited structural analyses. The two major classes of hemoglobin are type I (35% of total) and type IV (65%). Type IV is the major oxygen-transporting hemoglobin; it consists of three types of chain (in about equal quantities) and three types of chain (one major and two minor types). Several structural differences have been observed between these three (IV) chains and between the three (IV) chains, suggesting a complex genetic system governing the synthesis of these proteins. Moreover, a few amino acid substitutions occur at positions involved in contacts between chains, which suggests that differences in oxygen affinity may exist between these various type IV hemoglobins. Type I hemoglobin is less complex because it contains one type of chain and two chains; the latter two differ in numerous positions, suggesting duplications of the (I)-globin gene. The and chains of type I hemoglobin differ considerably from the and chains of type IV hemoglobin, indicating the existence of (I)- and (I)-globin genes separate from the (IV)- and (IV)- globin genes.This study was supported in part by the Yugoslav-American Joint Funds, pp 812 (to G.D.E.), and by United States Public Health Service Research Grant HLB-05168 (to T.H.J.H.).     

Clonal propagation of Callistemon by tissue culture techniques

Callus development in Callistemon viminalis was readily achieved when axillary buds derived from nodal tissue were placed in a medium containing macro- and micro-nutrients, sucrose (0.06 M), inositol (300 M), nicotinic acid (20 M), pyridoxine hydrochloride (3 M), thiamine hydrochloride (2 M), riboflavin (10 M), cytokinins (5 M) and auxins (0.1 M). The presence of benzylaminopurine (5 M) and p-chlorophenoxyacetic acid (0.1 M) promoted the most vigorous callus development and sprout formation. Rooting of nodal material was rare but occurred readily following the transference of sprouts developed on callus to a basal medium containing sucrose and salts. Root initiation was stimulated, however, by the presence of auxins. Chlorophenoxyacetic acid while stimulating root initiation repressed root growth. Indole butyric acid stimulated both root initiation and shoot growth at concentrations of 0.005 to 0.1 M. The treatment of choice for rooting and shoot growth was the addition of indole butyric acid at a concentration of 0.01 M.