Control of basidiospore production by a nuclear gene in the fungus Coprinus congregatus

Summary The genetical control of basidiospore production by sporophores of the fungus Coprinus congregatus was studied. This species is characterized by a bipolar compatibility control, and homokaryons with complementary alleles A1 and A2 can be distinguished apart. We confirmed that the pale mushroom phenotype of the fungus is determined by a nuclear gene symbolized pal. This gene also controls a sporeless character and segregates independently of the mating-type locus. Dikaryons homoallelic for the pal ^– allele produce typical pale and sporeless sporophores, while heteroallelic (pal ⁺, pal ^–) and homoallelic (pal ⁺, pal ⁺) dikaryons produce normal or almost normal sporulating sporophores. In order to segregate homokaryons homoallelic for the pal gene (A1, pal ^–; A1, pal ⁺, A2, pal ^–; A2, pal ⁺), the following protocols were used: (a) the dikaryotization of stock homokaryons containing the pal ⁺ allele and of each mating type, A1 or A2, by dikaryotic mycelia homoallelic for the pal ^– allele; (b) the culturing of homokaryotic mycelia issuing from the germination of basidiospores from sporophores produced by dikaryotic mycelia heterokaryotic for the pal gene; (c) the culturing of mycelia grown from protoplasts obtained from dikaryons homoallelic for the pal ^– allele (D6 strain), and from homokaryons heteroallelic for the pal gene (H8), or homoallelic for pal ^#x002B;+ allele (H7). These techniques enabled us to segregate homokaryons of the four types defined above and were indispensable in the segregation of the pal ^– homoallelic homokaryons as no basidiospores were produced by typical pale mushrooms.     

Mode of uptake of sterol by Arthrobacter simplex

The mechanism of uptake of water-insoluble -sitosterol by a newly isolated strain of Arthrobacter simplex SS-7 was studied. The production of an extracellular sterol-pseudosolubilizing protein during growth of A. simplex on -sitosterol was demonstrated by isolating the factor from the cell-free supernatant and its subsequent purification by Sephadex G-150 column chromatography. The M _r of the purified sterol-pseudosolubilizing protein determined by SDS–PAGE was 19kDa. The rate of sterol pseudosolubilization (5.2×10^–3g l^–1h^–1) could not adequately account for the rate of sterol uptake (72×10^–3g l^–1h^–1) and the specific growth rate (56×10^–3 h^–1). However in the unfavourable growth condition, when the cells were treated with sodium azide at the level of 30–60% of MIC, the sterol pseudosolubilization accounted for nearly 74% of the total growth containing 96% free cells. Cellular adherence to substrate particles was found to play an active role in the normal growth of the strain on -sitosterol. Unlike sodium acetate-grown cells, whose surface activity was negligible (60mNm^–1), the sterol-grown cells had strong surface activity (40mNm^–1). The high lipid content and long chain fatty acids in the cell-wall of -sitosterol-grown cells probably contribute to the high sterol adherence activity of the cells.     

The linear tetrasaccharide,Galβ1-4GlcNAcβ1-6Galβ1-4GlcNAc,isolated from radiolabeled teratocarcinoma poly-N-acetyllactosaminoglycan resists the action ofE. freundii endo-β-galactosidase

A novel linear tetrasaccharide, Gal1-4GlcNAc1-6Gal1-4GlcNAc, was isolated from partial acid hydrolysates of metabolically labeled poly-N-acetyllactosaminoglycans of murine teratocarcinoma cells. It was characterized by exo-glycosidase sequencing and by mild acid hydrolysis followed by identification of all partial cleavage products. The tetrasaccharide, and likewise labelled GlcNAc1-6Gal1-4GlcNAc, resisted the action of endo--galactosidase (EC 3.2.1.103) fromE. freundii at a concentration of 125 mU/ml, while the isomeric, radioactive teratocarcinoma saccharides Gal1-4GlcNAc1-3Gal1-4GlcNAc and GlcNAc1-3Gal1-4GlcNAc were cleaved in the expected manner.Abbreviations WGA wheat germ agglutinin - BSA bovine serum albumin - [³H]GlcNAc1-4-GlcNAc1-4GlcNAcOL N,N,NN'-triacetylchitotriose reduced with NaB³H₄     

Partial mispairing and crossing-over between β0 and δ genes as the origin of the δ β0 thalassemia gene

Summary Two double heterozygous ⁰/⁰ thalassemic sibs of Mexican descent were studied. The father had a ⁰/⁰ genotype, while the mother, one sib and several maternal relatives were ⁰/⁰ heterozygotes. Parental consanguinity and an apparently low frequency of thalassemia among Mexicans suggested a possible common origin of both ⁰ and ⁰ genes. A hypothesis to explain such a possibility is proposed on the basis of a partial mispairing between ⁰ and genes followed by a crossing-over which would results in a ⁰ recombinant gene. This hypothesis could also be extended to explain the 22 gluala, 22 alaglu and 116 arghis Hb variants as recombinants from double crossing-over between and mispaired genes for which the name interstitial-Lepore is proposed.     

Protocol-dependence of equivalent circuit parameters of toad urinary bladder

Summary Determinations of current-voltage relationships are widely employed in the characterization of epithelial sodium transport. In order to determine the protocol dependence of transport parameters in the toad urinary bladder, studies were carried out in the presence and absence of amiloride, an inhibitor of active sodium transport. With symmetric positive and negative perturbations of the transepithelial electrical potential difference (0±100 mV) for 30 sec, the amiloride-sensitive current-voltage (i ^a -) relationship was near linear over the range –75+100 mV, indicating constancy of the conductance ^a and the apparent electromotive force E _Na, lumped parameters of the standard electrical equivalent circuit model of the active transport system. With a reverse protocol (±1000 mV) or 15 min perturbations thei ^a - relationships were highly nonlinear. Nonlinearity reflected voltage dependence of parameters: perturbations that increased active transport decreased E _Na and increased ^a, as evaluated from 10 sec perturbations of ; slowing of active transport produced the converse changes. These effects are usefully analyzed in both quasi-steady states and true steady states by means of a detailed equivalent circuit incorporating the significant ionic currents across each plasma membrane. Precise understanding of the significance of ^a and E _Na will require characterization of the partial ionic conductances on perturbation of .     

Effects of light on nitrate-limited Oscillatoria agardhii in chemostat cultures

The effects of the average light irradiance (I) on growth and nitrate uptake kinetics of the cyanobacterium Oscillatoria agardhii, in nitrate-limited chemostat cultures, were studied. Light was nonsaturating for I <9.4 Wm^–2, for all growth rates () studied. However, was throughout limited by the availability of nitrate. Under light-saturating conditions the kinetics of nitrate-limited growth could be adequately described by both the Monod and Droop equations. Under light-non-saturating conditions the internal nitrogen content (Q) was a function of both and I, for which new formulas were derived. The high uptake capacity (V _max) of nitrate-limited cells was independent of , but was significantly increased for cells growing at I <9.4 Wm^–2. The half-saturation constant for nitrate uptake (K _s ^u ) increased with increasing , but was independent of the prevailing light conditions. The effects of light during nitrate-limited growth were associated with the regulation in the nitrogen-containing pigments.The results reported herein have important consequences for the use of Q, K _s ^u and V _max values as indicators of nutrient-deficiency of natural populations.     

Variations in the rate of synthesis of beta and beta'' RNA polymerase polypeptides under the influence of certain factors.

Summary In merodiploid cells containing a double dose of structural genes of RNA polymerase subunits-rpoBand rpoC-the rate of and subunits synthesis is 2 times higher than in haploidcells. Missence mutation rpoC1 (tsX) alters polypeptide and inducesthe and subunits synthesis at increased rate, particularly at a nonpermissive temperature. When rpoBCoperon carrying mutation rpoC1 is duplicated no dosage effect is observed. In the rpoC ⁺/rpoC1 heterodiploid the rpoC1 mutation does not significantly accelerate RNA polymerase subunits synthesis i.e. is recessive with respect to rpoC ⁺ Rifampicin causes 6-fold stimulation of RNA polymerase subunits synthesis in a sensitive wild-type strain. The rpoC1 mutation itself accelerates the synthesis of these subunits 3-fold. In the presence of rifampicin the mutant strain produces 13–22-fold faster as compared to wild-type strain without the drug. Thus, the effects of rifampicin and the mutation are multiplied suggesting that these factors act independently. Similar data have also been obtained with rifampicin-treated cells of rpoB22 (ts22) amber-mutant.After UV-irradiation of cells and synthesis is depressed much stronger than the total protein synthesis. Infection with a transducing phage rif ^d-47 which carries rpoB gene provokes a higher rate of synthesis. When pre-irradiated cells (500 erg/mm²) are infected with this phage, the rate of synthesis grows 20-fold compared to irradiated, non-infected cells and 6.5-fold compared to intact cells.The data are discussed in terms of the possible regulatory mechanisms of RNA polymerase subunit synthesis.     

Proliferation and germination of somatic embryos from embryogenic suspension cultures in <Emphasis Type="Italic">Phœnix dactylifera</Emphasis>

The present study demonstrates a procedure for the rapid development of a high number of somatic embryos from embryogenic suspension culture. This method might be efficient for mass propagation of Phnix dactylifera L. Embryogenic callus placed in liquid medium with 10^–5M ABA yielded an average 72 embryos per 100ml of culture medium within 2months, while those placed on solid medium yielded an average of 33, 20 and 16 embryos per 100ml of culture medium respectively for 10^–7, 10^–6 and 10^–5 M ABA after 4months. The combination of 2,4-DIchlorophenoxyacetic acid (2,4-D) (4.5×10^–7M), glutamine (6.7×10^–4M), and ABA (10^–5M) (L8 liquid medium) showed a beneficial effect on somatic embryos production compared to 2,4-D and glutamine alone, while this combination significantly (p<0.05) increased the accumulation of storage proteins (144 and 138mgg^–1 DW respectively for Jihel and Bousthami noir cultivars) in somatic embryos. The somatic embryos which underwent maturation on medium containing only 4.5×10^–7M 2,4-D and 10^–5M ABA (L6 liquid medium) accumulated more sugars (292 and 265mgg^–1 DW respectively for Jihel and Bousthami noir) than those matured on any other liquid medium. Histological studies revealed that somatic embryos (developed in L6 and L8 liquid media) accumulated less reserve compounds (proteins and sugars) than zygotic embryos. The addition of activated charcoal (0.25 and 0.5gl^–1) and phytagel^® (2.5gl^–1) to the germination medium may be useful for enhancing the germination of Phnix dactyliferasomatic embryos.     

Solution conformations of proline rings in proteins studied by NMR spectroscopy

Summary Three different conformations of proline rings in a protein in solution, Up, Down and Twist, have been distinguished, and stereospecific assignments of the pyrrolidine -, - and -hydrogens have been made on the basis of ¹H-¹H vicinal coupling constant patterns and intraresidue NOEs. For all three conformations, interhydrogen distances in the pairs -³, ³-³, ²-², ²-², and ³-³ (2.3 Å) are shorter than those in the pairs -², ²-³, ³-², ²-³, and ³-² (2.7–3.0 Å), resulting in stronger NOESY cross peaks. For the Up conformation, the ³-² and ²-³ spin-spin coupling constants are small (<3 Hz), and weak cross peaks are obtained in a short-mixing-time (10 ms) TOCSY spectrum; all other vicinal coupling constants are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. For the Down form, the -², ²-³, and ³-² vicinal coupling constants are small, leading to weak TOCSY cross peaks; all other couplings again are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. In the case of a Twist conformation, dynamically averaged coupling constants are anticipated. The procedure has been applied to bovine pancreatic trypsin inhibitor and Cucurbita maxima trypsin inhibitor-V, and ring conformations of all prolines in the two proteins have been determined.     

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     

Biosynthesis of RNA polymerase in Escherichia coli

Summary Effect of temperature-sensitive, assembly-defective mutations in Escherichia coli RNA polymerase (rpoB) or subunit gene (rpoC) was investigated on the expression of wild-type rpoB ⁺C⁺operon, which was introduced by infection of a lambda transducing phage drif ⁺ (rpoB ⁺)-6 after UV-irradiation of the mutant cells. In rpoB2·rpoB7 strain which accumulates assembly-intermediates, free , ₂ complex and premature core, the expression of rpoB ⁺C⁺operon measured by the rate of subunit synthesis was considerably inhibited whereas that of EF(translation elongation factor)-Tu, ribosomal proteins L1 and L7/L12, and some -coded proteins remained unaffected. On the other hand, the expression was enhanced specifically for only rpoB ⁺C⁺operon in either rpoC4 or rpoC1 mutants, which are defective in the association of ₂ complex and subunit or the activation of premature core enzyme, respectively. Upon preincubation of the mutant cells at 42° C prior to phage infection, during which assembly intermediates degraded rapidly, the rate of subunit synthesis relative to other phage-corded proteins increased remarkably in rpoB2·rpoB7 mutant as well as in rpoC4 and rpoC1 mutants. These observations strongly suggested the autogenous regulation for at least (rpoB ⁺C⁺) operon by some trans-active diffusible protein complexes built of RNA polymerase subunits. Nature of the regulatory molecules is discussed.Paper VI in this series is Saitoh and Ishihama (1977)     

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.     

<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.     

Cytophotometric evidence for the transformation of oocytes into nurse cells inDrosophila melanogaster

Summary A small proportion of ovarian chambers from females homozygous for theotu ⁷ (forovariantumor) mutation contain an oocyte that in its nuclear morphology resembles a nurse cell. Such transformed oocytes also appear in colchicine-poisoned wild type ovaries. Cytophotometric estimates demonstrate that these oocytes have undergone 3–4 additional DNA replications, but that they lag behind the adjacent nurse cells by an average of 1.3 replication cycles. It follows that, under certain circumstances, the definitive oocyte can switch to the nurse cell developmental pathway and therefore that a mechanism normally exists for preventing the further replication of its DNA. In the case ofotu ⁷, oocytes sometimes restart their endocyclic DNA replications and produce paired, polytene, homologous chromosomes.     

Double staining of intracellular cytokine proteins and T-lymphocyte subsets. Evaluation of the method in blood and bronchoalveolar lavage fluid

An immunocytochemical staining method has been developed for simultaneous staining of both cell surface markers (CD4 and CD8) and intracellular cytokine proteins IFN-, IL-4 and IL-5. Cell surface molecules were visualized with alkaline phosphatase, which was developed by Fast Blue BB. Intracellular cytokine proteins were detected by amino-ethyl carbazole. We applied this technique to T cells from T-cell lines and T-cell clones, peripheral blood mononuclear cells and broncho-alveolar lavage fluid cells. Cells were used either unstimulated or stimulated for 4h with 1ng/ml PMA and 1g/ml ionomycin, which proved to be an optimal stimulus taking cytokine staining, cell recovery and cell viability into account. We studied peripheral blood mononuclear cells from healthy subjects and found that without in vitro stimulation on average 0.4% of the cells were IFN- positive cells. In unstimulated broncho-alveolar lavage fluid cells of the 2 allergic asthmatic subjects studied so far we found higher numbers of cytokine-positive cells (up to 22% of the lymphocytes being IL-4⁺ cells). By in vitro stimulation, the numbers of cytokine-positive peripheral blood mononuclear cells from the healthy subjects were increased to maximally 5% IFN-⁺ cells. In stimulated lavage fluid cells from allergic asthmatic subjects maximally 34% of the lymphocytes became IFN-⁺. We conclude that this method allows detection of intracellular cytokine proteins in both CD4⁺ and CD8⁺ T cells without the need for stimulating the cells in vitro. In vitro stimulation may change the cytokine profile detected.     

Style morph frequencies in Minnesota populations of Lythrum (Lythraceae)

Style morph frequencies (shortmidlong) were determined for a total of n = 11 918 plants in 16 Minnesota populations of Lythrum salicaria L. Nine populations were in the establishment phase, with population sizes ranging from n = 56 to n = 2 192. Most of these populations exceeded previously reported population sizes in the native European habitat. A nonparametric statistical test, the chi-square (²), can be used to determine if populations are at isoplethic equilibrium (111, shortmidlong); a ² value >5.99 is significant at the 5% level. Only one established population (White Bear Lake, n = 1991, ² = 3.0) fitted the null hypothesis for isoplethy, although all established populations contained all three style morphs. Pooled values for these populations indicated an excess of mids and longs, with shorts being deficient. Colonizing populations had a higher percentage of mids (54%) when compared to established populations (33.7%). Short styles were almost nonexistent (8%) in colonizing populations. Five out of the seven populations lacked at least one style morph. A review of the literature reporting style morph frequencies in tristylous L. salicaria revealed that no statistical analysis for isoplethy has been performed. Darwin originally assumed that all populations would be isoplethic, possessing equal numbers of all three style morphs, but concluded, without statistical analysis, that, instead, populations were anisoplethic. Since tests for statistical deviations from the expected frequencies (111) have not been used, ² analysis was performed. Several of these populations were at isoplethic equilibrium (Nadder su2 = 1.7, Blelham ² = 1.69, Potsdam ² = 1.5, Vestfold ² = 0.4, Buskerud ² = 5.62, Kilchberg ² = 0.35, Lausanne ² = 3.32, Canberra ² = 5.29, Massachusetts ² = 3.13), suggesting that the general conclusion of anisoplethy in tristylous L. salicaria is inappropriate.This is Scientific Journal Series Paper Number 19 128 of the Minnesota Agricultural Experiment Station     

Electrogenic properties of the sodium-alanine cotransporter in pancreatic acinar cells: II. Comparison with transport models

Summary In this paper, the results of the preceding electrophysiological study of sodium-alanine cotransport in pancreatic acinar cells are compared with kinetic models. Two different types of transport mechanisms are considered. In the simultaneous mechanism the cotransporterC forms a ternary complexNCS with Na⁺ and the substrateS; coupled transport of Na⁺ andS involves a conformational transition between statesNCS andNCS with inward- and outward-facing binding sites. In the consecutive (or ping-pong) mechanism, formation of a ternary complex is not required; coupled transport occurs by an alternating sequence of association-dissociation steps and conformational transitions. It is shown that the experimentally observed alanine- and sodium-concentration dependence of transport rates is consistent with the predictions of the simultaneous model, but incompatible with the consecutive mechanism. Assuming that the association-dissociation reactions are not rate-limiting, a number of kinetic parameters of the simultaneous model can be estimated from the experimental results. The equilibrium dissociation constants of Na⁺ and alanine at the extracellular side are determined to beK _N <-64mm andK _S <-18mm. Furthermore, the ratioK _N /K _N ^S of the dissociation constants of Na⁺ from the binary (NC) and the ternary complex (NCS) at the extracellular side is estimated to be <-6. This indicates that the binding sequence of Na⁺ andS to the transporter is not ordered. The current-voltage behavior of the transporter is analyzed in terms of charge translocations associated with the single-reaction steps. The observed voltage-dependence of the half-saturation concentration of sodium is consistent with the assumption that a Na⁺ ion that migrates from the extracellular medium to the binding site has to traverse part of the transmembrane voltage.     

Specific Cd2+ uptake of encapsulated Aureobasidium pullulans biosorbents

Calcium alginate capsules containing Aureobasidium pullulans cells were prepared by an in-situ one-step method. The Cd²⁺uptakes of free biosorbent and capsule biosorbent were described well by the Freundlich isotherms. The Cd²⁺ uptake of capsule biosorbent was lower than that of free biosorbent with Cd^{2 +}at 100 mg l^–1. The total cadmium uptake of capsule biosorbent increased with the increase in encapsulated cell density and plateaued at a value of 23 g Cd²⁺/capsule with 150 g dry biosorbent l^–1 core volume of a capsule. The specific cadmium uptake of encapsulated biosorbent was 85% to that of free biosorbent at 35 g biosorbent dry weight l^–1 core volume of a capsule, decreased to 35% at 176 g biosorbent dry weight l^–1.