An α-spectrin mutation responsible for hereditary elliptocytosis associated in cis with the αV/41 polymorphism

The 207 LeuPro mutation in spectrin has recently been identified as a cause of ^I/50-46a hereditary elliptocytosis (HE) or pyropoikilocytosis among Black people. We have found this mutation in a Moroccan family in both the heterozygous and homozygous states. The mutated -spectrin allele carried, in cis, the ^V/41 polymorphism, a common polymorphism altering the peptide maps and associated with a low-expression level. This is the first report of the cis combination of an HE mutation and the ^V/41 polymorphism. Presumably, such a combination accounts for the very low expression of the abnormal allele in the heterozygous state.     

Regional Differentiation in the Dynamics of the Pollen Seasons of Alnus, Corylus and Fraxinus in Poland (Preliminary Results)

In 1995–1996 a study of pollen concentrations of Corylus, Alnus and Fraxinus was performed at seven sites in regions of different climatic and natural conditions. The aim of the study was to determine whether regional differences in the course and duration of pollen seasons occur in Poland. The study was performed using a volumetric method. Several phases during the pollen season were defined for each taxon (1, 2.5, 5, 25, 50, 75, 95, 97.5, 99% of annual total) and duration of the pollen seasons was calculated using 98 and 90% methods. Dynamics and duration of the pollen seasons and a start of particular phases of the season were compared among sites. On the basis of the preliminary analysis it could be supposed that regional differences were most evident in the case of Corylus. The pollen season of this taxon started the earliest in Pozna where thermal conditions were most favourable and the latest in Gdask, a place at the furthest to the north ( ², 0.05). In montane regions (Zakopane, Rabka) last phases of the season were significant extended ( ², 0.05). Probably it results from secondary pollen deposition and a long-distance transport by montane wind. In case of Fraxinus the significant regional differences in the start of the pollen season were not found. The study supported that weather conditions have the substantial influence on the start of consecutive phases of the pollen season.     

Mutants with decreased differentiation to plasmodia in Physarum polycephalum

Summary Mutant (APT) amoebae that display reduced ability to form plasmodia asexually were isolated by the use of an enrichment procedure. The results of reconstruction experiments show that the procedure enriches only for mutants blocked early in the pathway from amoeba to plasmodium. Mutants were isolated from four parents, two of which produce plasmodia asexually because they carry the allele mth of the mating type locus, and two because they carry gad (greater asexual differentiation) mutations. The APT mutants varied widely in the frequency of residual plasmodium formation, which occurred, in some cases, by reversion. The mutants, called apt (amoeba to plasmodium transition), were recessive in diploids and linked to the mating type (mt) locus. Mutants derived from the gad parents, unlike the parents themselves, crossed readily with heterothallic amoebae. Progeny analysis from such crosses indicates that both gad mutations are linked to mt. The mutants derived from one of the mth parents fell into two groups on the basis of their ability to cross with the mutants derived from the mt2 gad-8 parent. The result suggests that the mth-derived mutants represent two or more complementation groups. Mutants derived from the mt2 gad-8 parent cross with mt2 amoebae and hence display an altered mating specificity.     

Ernst Mayr as community architect: Launching the society for the study of evolution and the journalEvolution

Ernst Mayr's contributions to 20th century biology extend far beyond his defense of certain elements in evolutionary theory. At the center of mid-century efforts in American evolutionary studies to build large research communities, Mayr spearheaded campaigns to create a Society for the Study of Evolution and a dedicated journal,Evolution, in 1946. Begun to offset the prominence ofDrosophila biology and evolutionary genetics, these campaigns changed course repeatedly, as impediments appeared, tactics shifted, and compromises built a growing coalition of support. Preserved, however, were designs to balance the community and journal with careful equation of status and explicit partitioning of responsibilities within the working coalition. Choice terms such as cooperation and unity carried a strong political message. Mayr's editorship ofEvolution provides a superb example of these balancing efforts. The mid-century infrastructural activities described herein also represented aggressive attempts to leverage control across several layers of community. Leaders of these campaigns sought: (1) to promote evolutionary studies as a modernized research discipline and place it at the center of American biology, (2) to promote evolutionary studies within existing disciplines — e.g. systematics, genetics, and paleontology, (3) to foster certain research styles within evolutionary studies, and (4) to emphasize certain solutions to prominent research questions. Throughout, Mayr interjected his priorities, tactics and energy.     

Thiol-induced oligomerization of α-lactalbumin at high pressure

Denaturation and aggregation of-lactalbumin at high pressure (up to 10 kbar, 1000 MPa) were studied by means of circular dichroism, gel-permeation chromatography, sodium dodecyl sulfate and gel electrophoresis. It was found that the unfolding of-lactalbumin at high pressure is reversible even in basic pH and at a protein concentration as large as 10%. In these conditions only a negligible fraction of the protein is denatured irreversibly and aggregates. The rate of aggregation of-lactalbumin at high pressure increases significantly in the presence of low-molecular reducing agents such as cysteine, 2-mercaptoethanol, and dithiothreitol. Maximal yield of-lactalbumin oligomerization (over 90%) was achieved in the presence of cysteine at the molar cysteine/protein ratioq=2 and atpH 8.5. Apparent molecular weight of the obtained oligomers was over 500 kDa. It was shown that the size distribution of oligomers can be modulated by varyingpH and reducing agent. The size distribution shifts in the direction of very large, poorly soluble particles whenpH decreases. Maximal content of the insoluble fraction (about 30%) can be reached at pH 5.5 when cysteine (q=2) is used as reducing agent. The oligomers of-lactalbumin are stabilized mainly by nonnative interchain disulfide bridges. Circular dichroism measurements point to an additional mechanism of cohesion of polypeptide chains in the oligomers, which is formation of intermolecular-sheets.     

Studies on the sites expressing evolutionary changes in the structure of eukaryotic 5S ribosomal RNA

Summary We have determined the complete sequences of 5S rRNAs from a lamprey (Lampetra reissneri), a lancelet (Branchiostoma belcheri), silkworms (Philosamia cynthia ricini, Bombyx mori, Antheraea pernyi), and a silkworm hybrid (artificially fertilized hybrid species ofPhilosamia cynthia ricini x Bombyx mori ), as well as those of cotton seeds (Gossypium hirsutum L.). Having compared more than 170 eukaryotic 5S rRNAs of which seven sequences have been determined by our group as mentioned above, we have found that the evolutionary sites that exist at special locations in these structures are closely related to the evolution of eukaryotes. The changes proceed step by step in an orderly way, i.e., the change in nucleotide residues of the evolutionary sites depends on the order of the evolution of the species and shows group-specific patterns.     

Fruiting studies in species ofCapronia (Herpotrichiellaceae)

A recently described protocol for thein vitro production of ascomata was employed to determine the sexual incompatibility systems of five species ofCapronia. The formation of mature ascomata in isolates derived from single ascospores demonstrated thatC. epimyces, C. mansonii, andC. munkii n. sp. are homothallic. In contrast, fertile ascomata were observed only in mass-ascospore isolates and pairwise crosses between specific single-ascospore isolates inC. dactylotricha n. sp. andC. moravica. TheExophiala anamorphs ofC. dactylotricha andC. munkii are described and aPhialophora-like synanamorph is reported for the former species. Germinating ascospores ofC. munkii formed conidiogenous cells directly, while the ascospores of the remaining species germinated to produce germ tubes and hyphae. The application of the terms microcyclic conidiation to secondary conidium production and sclerotial body and stroma to the multicellular structures produced by species ofCapronia andExophiala are discussed.     

Effect of cotton dust and 2,4-D on Host-parasite relationship. (I) cotton and Fusarium-wilt

Summary The pathogenFusarium solani sensuSnyder &Hansen, as identified byW. L. Gordon was recorded in the present work as a new species causing cotton wilt in Egypt. Cotton dust in varying concentrations does not significally alter the normal infection of both Menoufi and Giza 26 cotton varieties towardsFusarium. Similarly the potency ofFusarium filtrate to induce wilting did not appreciably change with previous treatment of cotton plants with cotton dust. On the other hand leaves treated with 2,4-D showed the maximal water loss. Percentage infected Giza 26 cotton seedlings were found to be comparatively less in soil infected with 2,4-D treatedFusarium mycelium than in that infected with untreated mycelium.     

Transposon Tn1 intra-molecular transposition

Summary A system for the direct selection of intra- and inter-molecular transposition events has been used to show that intra-molecular transposition of Tn1 generates deletions and inversions and requires the tnpA but not the tnpR gene product, as predicted by current models of transposition. Intra-molecular Tn1 transposition is much less limited by transposition immunity than inter-molecular transposition, and occurs at frequencies comparable to those for inter-molecular transposition. The selection system, which uses the bacteriophage cI-P_R region as a target can be used to select, quantify, and characterize any spontaneous or induced mutations.     

Ion content and aperture in “isolated” guard cells ofCommelina communis L.

Summary Isolated guard cells ofCommelina communis L., in epidermal strips in which all cells other than guard cells have been killed by treatment at low pH, will open to a degree dependent on the K (Rb)/Cl(Br) concentration in the bathing medium. Estimates of the changes with aperture of the ion concentrations in the guard cells were made by measurement of⁸⁶Rb uptake from RbCl, of⁸²Br uptake from K⁸²Br, and of potassium activity with a potassium-sensitive microelectrode. The osmotic effects of such changes were compared with the previous estimates of the osmotic changes required to change the aperture. The results suggest that a substantial fraction of the osmotic pressure of isolated guard cells is contributed by solutes other than KCl (or other potassium salts), and that, even in stomata opened by incubation on KCl solutions, a substantial fraction of the increase in osmotic pressure associated with opening is contributed by solutes other than KCl.     

Immunochemistry of membrane F1-Adenosine triphosphatase fromMicrococcus lysodeikticus. Role of the alpha subunit

The membrane-bound ATPase activity from two substrains ofMicrococcus lysodeikticus, designated as A and B, was inhibited by antibodies raised against the two forms of purified F₁-ATPase. Form B of the enzyme, which behaved as a poorer immunogen than form A, also showed less reactivity as an antigen, independent of the physical state of the F₁-ATPase form. Antibodies were raised against the two major subunits ( and ) isolated fromM. lysodeikticus F₁-ATPase form A, which was the most stable form of the enzyme. Anti-(-subunit) serum strongly inhibited the ATPase activity of membrane-bound ATPase but showed little inhibition of the purified, soluble F₁-ATPase. The anti-(-subunit) serum inhibited the soluble F₁-ATPase, but to a lesser extent than the membrane-bound enzyme. In any event, the effect of anti- antibodies on the membrane-bound ATPase was smaller than that of anti- antibodies. It was postulated that the subunit ofM. lysodeikticus F₁-ATPase plays an essential and regulatory role in the expression of the immunochemical properties of the protein.     

Fromβ-lactams toα- andβ-amino acid derived peptides

Summary The potential of-lactams as intermediates for the access to- and-amino acid-derived peptides is shortly reviewed, with major focus on the technologies developed in our group. The two general strategies lie, on one side, in the oxidative ring expansion of 3-hydroxy-lactams toN-carboxy-amino acid anhydrides or Leuch's anhydrides and subsequent coupling with-amino acid esters and, on the other side, in the nucleophilic ring opening ofN-Boc--lactams. Both approaches have been successfully applied to the synthesis of,-diamino acid,-amino--hydroxy acid, polyhydroxylated-amino acid,,-disubstituted-amino acid,-amino acid,-amino--hydroxy acid and,-disubstituted-amino acid derived peptides. Because of the mild reaction conditions needed for the above transformations and the highly stereoselective procedures employed for the construction of the starting-lactam ring, the whole process allows the production of optically pure final products.     

Extended serotyping scheme forVibrio cholerae

Fifty-seven new O serogroups have been added to the existing serotyping scheme ofVibrio cholerae to extend the scheme from O84 to O140. Prominent new additions were serogroups O139 and O140. The reference strain of O139 was isolated from a patient from an epidemic of cholera-like diarrhea in Madras, Southern India. Serogroup O140 was assigned to a group ofV. cholerae strains which were tentatively named as the Hakata serogroup and which possessed the C (Inaba) factor but not the B (Ogawa) nor the A (major specific antigen of O1 serogroup ofV. cholerae). As all antisera against reference strains ofV. cholerae contained some amount of antibody to the rough (R) antigen, all diagnostic O antisera must be absorbed with the reference rough strain, CA385.     

An investigation into the mechanism for reduced seed yield inLotus corniculatus

Summary A study of seed position in the pod ofLotus corniculatus L. cv. Mirabel (Fabaceae) suggested that reduced seed set after self-pollination is not due to an inability of the self-pollen tube to reach the end of the ovary. As in other cultivars, it has been demonstrated that cultivar Mirabel produced less seed per pod and shorter pods after self- than after cross-pollination. No differences were noted for percent germination of seeds produced by both types of pollination indicating that the number of seeds per pod is a reliable index of the ultimate productive potential of the pollination.     

Incompatibility in someSolanum crosses

Conclusions and Summary There are four conclusions: (1)Solanum kurtzianum, S. simplicifolium andS. michoacanum possess an ordinary one locus system; (2) the three species ofMegistacroloba investigated are sufficiently closely allied to express, with little irregularity, a common incompatibility system; (3) several crosses involvingS. infundibuliforme, four wild species of the seriesTuberosa and certain cultivated diploids show a highly irregular expression of the incompatibility system which is much influenced by erratic female sterilities; and (4) the combinationS. simplificifolium x Phureja cultivar group shows an entirely anomalous behaviour (which is consistent in reciprocal) in which only three compatibility groups can be recognized in the approximate numerical ratio 121; for this there is yet no explanation.     

A preliminary phylogeny for the NeotropicalRubiaceae

The sequence of subfamilies,Cinchonoideae, Antirheoideae andRubioideae, attemps to show their natural affinities and phylogeny. The subfamilies are those ofVerdcourt, and the order in which they are presented is that ofBremekamp. A list is presented of the subfamilies, tribes and genera of theRubiaceae to be utilized in the Catálogo Ilustrado de las plantas de Cundinamarca, Colombia.     

Ultrastructure of the stem of the aquatic plantCallitriche stagnalis L.

Summary The submerged stem ofCallitriche stagnalis L. has been studied by light and electron microscopy. The presence of plastids with an opaque body are noted in the parenchymatic cells near the conducting elements as well as many microtubules associated with polyribosomes and vesicles near the cell wall.It is of particular interest to note that the tracheids are connected to the pith lacuna and each other to form only one conducting cylinder, so that functionally theCallitriche stele seems to be a protostele. This reduction of the stele is probably due to the environment conditions, since by floral morphology this aquatic plant is considered an evolved species.     

Life cycle ofPseudodiamesa branickii (Chironomidae) in a small upland stream

The generation time ofP. branickii was studied using larval samples in conjunction with rearing experiments and continuous collection of egg masses across one year. This species produced three generations per year in a central German stream (280 m a.s.l., 50° 40 N). Its generation time was variable and obviously influenced by the photoperiod to which eggs and larvulae were subjected. It is thus concluded that two strains ofP. branickii were present in a single population, one bivoltine and the other trivoltine.     

Characterization of carotene accumulation inUstilago violacea using high-performance liquid chromatography

Quantitative analysis of carotene accumulation in white, pink, pumpkin, orange, and yellow haploid strains ofUstilago violacea by high-performance liquid chromatography indicated that specific patterns of carotene accumulation are primarily responsible for the white, pumpkin, orange, and yellow phenotypes. The yellow strains accumulated primarily -zeacarotene and -carotene. The white strains accumulated primarily the colorless carotene, phytoene, or did not accumulate any carotene at all. Carotene accumulation in pink haploid strains followed the same patterns as for the white, pumpkin, orange, or yellow strains. Pink diploid and disomic strains ofU. violacea with various parental combinations of the color mutations accumulated either cis--zeacarotene and -carotene or only -carotene. The pattern of carotene accumulation in conjunction with the available genetic information for the carotene loci inU. violacea was used as a basis for the construction of a new genetic model for carotene biosynthesis inU. violacea. The model employs three dehydrogenases and one cyclase for the synthesis of -carotene from phytoene, and accounts for the carotene accumulation patterns of either cis--zeacarotene and -carotene or lycopene, -carotene, and -carotene.     

Influence of photoperiod,temperature and host plant on the production of diapause eggs inPetrobia (Tetranychina) harti (Acari: Tetranychidae)

Petrobia harti (Ewing) diapauses in the egg stage. Adult females lay either diapause or nondiapause eggs. On the University of Thessaloniki campus (41°N), the mite was found to develop on leaves ofOxalis corniculata L. throughout the year, while no mites were found on leaves ofOxalis articulata Savigny growing in the same area. In the laboratory the mite could be maintained equally well on detached leaves of both plant species, kept on wet cotton-wool.Forty to 90% females laying diapause eggs (dlf) were produced when the mites developed under LD 1212 and 19±1 °C, or LD 168 and 19±1 °C or 25±1 °C on leaves ofO. articulata detached from plants grown in the open in various seasons. Under the same conditions, a very low to zero percentage ofdlf was produced onO. corniculata. By rearing certain feeding stages on one of these twoOxalis hosts, and the other feeding stages on the other host, various percentages ofdlf were obtained. These percentages were the net effect of the antagonistic action of the twoOxalis species.By rearing the mites at LD 8.515.5, LD 1212 or LD 168 and a temperature of 19±1 °C onO. articulata leaves renewed every 3 days, or every 16–18 days, or not at all, it could be shown that diapause induction or aversion is caused by the direct effect of photoperiod on the mites, and not by an effect through the host leaves.When wholeO. articulata plants were grown under LD 168 and 19±1 °C in the laboratory, or developed in the open during April and May, flowers were produced, while under LD 1212 no flowering occurred. In the laboratory under diapause-inducing conditions, higher percentages ofdlf were produced on leaves detached from flowering plants than on leaves detached from plants not flowering.OnO. articulata leaves at 20 °C, photoperiods with photophases equal to or longer than 12 h induced from 70 to 80%dlf, while photoperiods with photophases equal to or shorter than 10.9 h induced very low to zero percentages. By transferring different chrysalis stages from a diapause-inducing (LD 1212) to a diapause-averting (LD 8.515.5) photoperiod, and vice versa, it was found that the nymphochrysalis through deutonymph stages were sensitive to photoperiod, the deutochrysalis and deutonymph being the most sensitive.Under an LD 1212 photoperiod, a temperature of 20 °C induced diapause, whereas 25 °C, 30 °C, or a daynight thermoperiod of 25 °C18 °C suppressed it.