Inhibition of L-type Ca<Superscript>2+</Superscript> current in guinea pig ventricular myocytes by cisapride

The effect of cisapride on L-type Ca²⁺ current (I _Ca,L) was studied in guinea pig ventricular myocytes using a whole-cell voltage-clamp technique and a conventional action potential recording method. Myocytes were held at –40 mV, and internally dialyzed and externally perfused with Na⁺- and K⁺-free solutions; cisapride elicited a concentration-dependent block of peakI _Ca,L, with a half-maximum inhibition concentration (IC₅₀) of 46.9 µM. There was no shift in the reversal potential, nor any change in the shape of the current-voltage relationship ofI _Ca,L in the presence of cisapride. Inhibition of cisapride was not associated with its binding to serotonin or to -adrenergic receptors because ketanserin, SB203186, and prazosin had no effect on the inhibitory action of cisapride onI _Ca,L. Cisapride elicited a tonic block and a use-dependent block ofI _Ca,L. These blocking effects were voltage dependent as the degree of inhibition at –40 mV was greater than that at –70 mV. Cisapride shifted the steady-state inactivation curve ofI _Ca,L in the negative direction, but had no effect on the steady-state activation curve. Cisapride also delayed the kinetics of recovery ofI _Ca,L from inactivation. At a slow stimulation frequency (0.1 Hz), the action potential duration in guinea pig papillary muscles showed biphasic effects; it was prolonged by lower concentrations of cisapride, but shortened by higher concentrations. These findings suggest that cisapride preferentially binds to the inactivated state of L-type Ca²⁺ channels. The inhibitory effect of cisapride onI _Ca,L might play an important role in its cardiotoxicity under pathophysiological conditions, such as myocardial ischemia.     

Denitrification of nitrate to nitrogen gas by washed cells ofRhizobium japonicum and by bacteroids fromGlycine max

Nitrate, nitrite and nitrous oxide were denitrified to N₂ gas by washed cells ofRhizobium japonicum CC706 as well as by bacteroids prepared from root nodules ofGlycine max (L.) Merr. (CV. Clark 63). Radiolabelled N₂ was produced from either K¹⁵NO₃ or Na¹⁵NO₂ by washed cells ofRh. japonicum CC705 grown with either nitrate only (5 mM) or nitrate (5 mM) plus glutamate (10 mM). Nitrogen gas was also produced from N₂O. Similar results were obtained with bacteroids ofG. max. The stoichiometry for the utilization of¹⁵NO ₃ ^- or¹⁵NO ₂ ^- and the produciton of¹⁵N₂ was 2:1 and for N₂O utilization and N₂ production it was 1:1. Some of the¹⁵N₂ gas produced by denitrification of¹⁵NO ₃ ^- in bacteroids was recycled via nitrogenase into cell nitrogen.     

A new type of cuvette for the measurement of daily variation of CO<Subscript>2</Subscript> efflux from stems and branches in controlled temperature conditions

A miniaturized, porometer-compatible cuvette for measurements of CO₂ efflux from woody plant parts at controlled temperature conditions is described. A copper cuvette equipped with a PID-controlled Peltier element regulates cortex temperature in three modes: (1) synchronized with ambient air temperature; (2) at a constant difference in the range of ±10°C from air temperature; and (3) constant at a temperature in a range of ±25°C difference from ambient air. This method allows investigation of (a) respiratory capacity of woody plant parts dependent on short-term temperature variations, (b) CO₂ release from woody plant parts following exposure to the sun, and (c) acclimation of woody plant parts to long-term changes of temperature. By use of the copper cuvette, temperature gradients in the cortex are drastically reduced. Therefore, studies on the effect of metabolically and physico-chemically based processes on diurnal variations of CO₂ efflux from woody plant parts can be carried out. Field experiments were carried out on trees of Betula pendula, B. ermanii, and B. litwinowii. At synchronized temperatures of ambient air and woody plant tissue, daytime reductions of CO₂ efflux relative to night-time rates at a given temperature from branches of B. pendula and B. ermanii were observed. In July, CO₂ efflux from branches of B. litwinowii under controlled temperature conditions from 3 to 27°C showed a characteristic exponential increase from 0.6 to 7.2 µmol CO₂ m^–2 s^–1. During dormancy, long-term warming of branches of B. ermanii failed to increase metabolic activity.     

Adaptation of stomatal response ofCamellia rusticana to a heavy snowfall environment: Winter drought and net photosynthesis

The adaptation ofCamellia rusticana, an evergreen broad-leaved shrub found in areas of heavy snowfall in Japan, to heavy snowfall environments, and the mechanisms by which it is damaged in winter above the snow, were investigated. The stomatal response and photosynthetic characteristics ofC. rusticana were compared to those ofCamellia japonica found in areas of light snowfall. In field conditions, the mean net photosynthesis ofC. rusticana at photon flux density (PFD) over 200 μmol m⁻²s⁻¹ (Pn(_>200). was 50% larger than that ofC. japonica, but in both light saturated and CO₂ saturated conditions, the O₂ evolution rate (Pc) ofC. rusticana was not different from that ofC. japonica. Mean leaf conductance at PFD over 200 μmol m⁻²s⁻¹ (gl(_>200)) was about 100% larger than that ofC. japonica in the field. The Pn(_>200)) was 50% ratio ofC. rusticana was 37% higher than that ofC. japonica which suggests thatC. rusticana's larger Pn(_>200) can be explained by its larger gl(_>200). WhenC. rusticana trees wintering underneath the snow were projected above it, the leaves of these plants showed serious drought within five days in non-freezing conditions. Their Pc and the maximum stomatal conductance decreased by half and did not recover. The leaves ofC. rusticana showed larger gl(_>200) and a less sensitive stomatal response to the decrease of leaf water potential than that ofC. japonica. The stomata characteristics ofC. rusticana caused larger net photosynthesis than that ofC. japonica during the no snow period, and caused the need for snow cover in winter as protector from winter drought.     

Intergeneric conjugal transfer of plasmid DNA from<Emphasis Type="Italic"> Escherichia coli</Emphasis> to<Emphasis Type="Italic"> Kitasatospora setae</Emphasis>, a bafilomycin B<Subscript>1</Subscript> producer

An effective transformation procedure for Kitasatospora setae was established based on transconjugation from Escherichia coli ET12567 (pUZ8002) using a C31-derived integration vector, pSET152, containing oriT and attP fragments. While no transconjugation was observed under the standard transconjugation conditions for Streptomyces species, sufficient transconjugation (>1×10^-6) was achieved on ISP4 medium containing 30 mM MgCl₂ using a 25- to 125-fold excess of E. coli donor cells. In addition, the sequence and location of the chromosomal integration site attB of K. setae was identified for the first time in genera of non-Streptomyces actinomycetes. K. setae contains a single C31 attB site. Similar to the case of Streptomyces species, the attB site of K. setae is present within an ORF encoding a pirin-homolog, but the K. setae-attB sequence deviates slightly from the consensus sequence of Streptomyces attB sequences.     

Genetic analysis of phosphomannomutase/phosphoglucomutase from<Emphasis Type="Italic"> Vibrio furnissii</Emphasis> and characterization of its role in virulence

The pmm gene from Vibrio furnissii, which encodes phosphomannomutase (PMM), was cloned and sequenced. The open reading frame consisted of 1,434 bp, encoding a polypeptide of 477 amino acids with a molecular mass of 53,325 Da. The predicted amino acid sequence of V. furnissii PMM showed high similarity with PMMs from other enteric bacteria, such as V. cholerae, Salmonella sp. and Escherichia coli. The PMM protein was overexpressed in E. coli as a His₆-tagged recombinant protein. The estimated apparent K_m and k_cat values of the purified recombinant protein for mannose 1-phosphate were about 60 M and 800 min^–1, respectively. To investigate the biochemical functions and the role of pmm in the virulence of V. furnissii, a pmm knock-out mutant was constructed by homologous recombination mutation. Under the various physical conditions, cell numbers of the wild-type and the mutant did not differ. Oral introduction of bacterial suspensions to a mouse model showed that the pmm-deficient mutant decreased in viability at the intestine. Microscopy of the isolated intestines from mice revealed significant damage after 3 days in intestinal mucosa infected with the wild-type as compared with the mutant. The pmm-deficient mutant caused a reduction of virulence in mice and the loss of O-antigen polysaccharide, and showed low resistance relative to the wild-type when incubated with normal human serum.     

Somatic embryogenesis and plant regeneration from immature zygotic embryos of<Emphasis Type="Italic"> Cryptomeria japonica</Emphasis> D. Don

This report describes the successful plant regeneration via somatic embryogenesis from immature zygotic embryos of Cryptomeria japonica D. Don. For the induction of embryogenic tissue, we determined that the optimal medium contained N⁶-benzyladenine and 2,4-dichlorophenoxyacetic acid. Immature zygotic embryos that were collected at the end of June yielded embryogenic tissue at the highest frequency. Embryogenic tissues that had proliferated in liquid medium included small and loosely packed cells and elongating or elongated cells. We used ten cell lines to determine the optimal medium for the development of somatic embryos. Induced somatic embryos germinated with synchronous sprouting of cotyledons, hypocotyls and roots. Gibberellin A₃ in the germination medium had a positive effect on both the elongation of hypocotyls and the survival of seedlings. The frequencies of induction and germination of somatic embryos differed among the cell lines examined. Most of the seedlings grew normally. This system of somatic embryogenesis required 4–5 months for the regeneration of C. japonica plantlets from immature zygotic embryos.Abbreviations ABA Abscisic acid - BA N⁶-Benzyladenine - 2,4-D 2,4-Dichlorophenoxyacetic acid - GA₃ Gibberellin A₃Communicated by F. Sato     

Dominance Relationship between Two Self-Incompatible<Emphasis Type="Italic">Brassica campestris</Emphasis> Haplotypes in Response to CO<Subscript>2</Subscript> Gas

InBrassica, self-incompatibility (SI) can be overcome by CO₂ application, an effective method for obtaining numerous inbred lines for F, commercial seed. We previously reported two different S-alleles ofBrassica campestris, S⁷³³ and S⁷³⁴, with extremely different degrees of susceptibility to this gas. In the current study, we raised a cross-population between those two genetic lines, and analyzed their reaction level of self-incompatibility to CO₂ (RLSICO₂). Here, all 40 of our progeny from the F₁ cross-population were susceptible, maintaining high values of RLSICO₂. This suggests that the susceptible line, S⁷³⁴, is dominant to the insusceptible line, S⁷³³. We also generated an F₂ selfing-population of each crossed progeny, S⁷³³♀ S⁷³⁴♂ and S⁷³³♂ S⁷³⁴♀, to assess the RLSICO₂ of each individual. PCR-RFLP analysis was performed to determine the S-genotype of the F₂ population. The S⁷³⁴ allele segregated in a theoretical ratio of the dominant trait, and the RLSICO₂ was consistent with the dominance relationship. Therefore, we have now demonstrated that high RLSICO₂ in β.campestris is controlled by a dominant gene. Both authors contributed equally to this work     

The effect of the supernatants obtained fromSporothrix schenkii andCandida albicans culture on the generation of reactive oxygen species by polymorphonuclear leukocytes

The effect of the supernatants obtained from the liquid culture medium ofSporothrix schenkii andCandida albicans on the generation of superoxide anion (O ₂ ^– and hydroxyl radicals OH_., the elements of reactive oxygen species (ROS), and chemilimunescence (CL), a measure of several ROS, by polymorphonuclear leukocytes (PMNs) was examined. In our study, it was shown that the supernatant ofS. schenkii increased all types of ROS generation examined and CL, while that ofC. albicans increased OH_. generation and CL. The effect of the supernatants ofS. schenkii on OH_. generation and CL and that ofC. albicans on CL were most remarkable when the supernatant obtained 8 weeks after the inoculation was used. The supernatant ofS. schenkii was shown to be a much more potent stimulant than the supernatant ofC. albicans. This ROS-stimulating effect of the supernatant ofS. schenkii was heat stable but not dialyzable. These findings suggest the possible role of ROS produced by infiltrated PMNs in the inflammatory skin lesions induced byS. schenkii.     

Purification and characterization ofFus sI3596, a 65 kd allergen ofFusarium solani

A component ofFusarium solani (F. solani), identified as the major allergen,Fus sI₃₅₉₆ ^* was purified to homogeneity from culture filtrate (CF) by means of anion-exchange column chromatography, gel filtration and FPLC. The homogeneity ofFus sI₃₅₉₆ ^* was assessed by IEF, PAGE, SDS-PAGE (non-reducing), immunoblot and HPLC.Fus sI₃₅₉₆ ^* was isolated as a glycoprotein of MW 65 kd and pI 3.6. The IgE ELISA-inhibition assay after periodate treatment of the fraction showed a lower IgE binding capacity suggesting involvement of carbohydrate moiety in IgE binding reactions of the allergen. Peptide fragments ofFus sI₃₅₉₆ ^* obtained after CNBr and trypsin treatment were analysed by immunoblotting for their allergenicity. This study indicated that there could be at least 3 allergenic determinants in the major allergen,Fus sI₃₅₉₆ ^* ofF. solani CF.Abbreviations DEAE diethyl aminoethyl - HPLC high performance liquid chromatography - SDS sodium dodecyl sulphate - PBS-Tween phosphate buffer saline containing 0.1% tween - DTT dithiothreitol - TFA triflouroacetate - FPLC fast protein liquid chromatography     

Evidence that high-dose<Emphasis Type="Italic">L</Emphasis>-arginine may be inappropriate for use by diabetic patients as a prophylactic blocker of methylglyoxal glycation

Previous reports have suggested that high-doseL-arginine could be used in diabetic patients as a prophylactic blocker for the initial glycation reaction of proteins by methylglyoxal (MG), a reactive dicarbonyl compound of glucose metabolism. Here, we present several lines of evidence to substantiate that this prophylactic intervention may be inappropriate and should be used with care. First, we demonstrated that when various concentrations ofL-arginine (2.0–8.0 mM) were added to a fixed concentration of MG (1.56 µM) in a buffered lucigenin solution, dose-dependent generation of superoxide anion (O ₂ ^– )-mediated ultraweak chemiluminescence (uwCL) occurs. The suppression of uwCL generation by exogenously added superoxide dismutase further substantiated that the interaction between MG andL-arginine generated O ₂ ^– . This phenomenon can also be demonstrated in a serum-based system. Furthermore, when a fixed concentration ofL-arginine (8.0 mM) was added exogenously to a group of sera obtained from either diabetic patients (n=10) or their matched nondiabetic controls (n=10), a marked discrepancy in the generation of O ₂ ^– -mediated uwCL could be demonstrated (12,534 ± 3,147 vs. 950 ± 350 counts; p<0.001). Taken together, this evidence demonstrates that the appropriateness of using high-doseL-arginine for prophylactic measures in diabetic patients may be questioned, because the inhibition of the glycation reaction between MG and proteins by high-doseL-arginine unexpectedly produces plethoric O ₂ ^– as a by-product, which may subsequently aggravate the preexisting oxidative stress status of diabetic patients.     

Fructose-1,6-bisphosphatase from<Emphasis Type="Italic"> Corynebacterium glutamicum</Emphasis>: expression and deletion of the<Emphasis Type="Italic"> fbp</Emphasis> gene and biochemical characterization of the enzyme

The class II fructose-1,6-bisphosphatase gene of Corynebacterium glutamicum, fbp, was cloned and expressed with a N-terminal His-tag in Escherichia coli. Purified, His-tagged fructose-1,6-bisphosphatase from C. glutamicum was shown to be tetrameric, with a molecular mass of about 140 kDa for the homotetramer. The enzyme displayed Michaelis-Menten kinetics for the substrate fructose 1,6-bisphosphate with a K_m value of about 14 µM and a V_max of about 5.4 µmol min^–1 mg^–1 and k_cat of about 3.2 s^–1. Fructose-1,6-bisphosphatase activity was dependent on the divalent cations Mg²⁺ or Mn²⁺ and was inhibited by the monovalent cation Li⁺ with an inhibition constant of 140 µM. Fructose 6-phosphate, glycerol 3-phosphate, ribulose 1,5-bisphosphate and myo-inositol-monophosphate were not significant substrates of fructose-1,6-bisphosphatase from C. glutamicum. The enzymatic activity was inhibited by AMP and phosphoenolpyruvate and to a lesser extent by phosphate, fructose 6-phosphate, fructose 2,6-bisphosphate, and UDP. Fructose-1,6-bisphosphatase activities and protein levels varied little with respect to the carbon source. Deletion of the chromosomal fbp gene led to the absence of any detectable fructose-1,6-bisphosphatase activity in crude extracts of C. glutamicum WTfbp and to an inability of this strain to grow on the carbon sources acetate, citrate, glutamate, and lactate. Thus, fbp is essential for growth on gluconeogenic carbon sources and likely codes for the only fructose-1,6-bisphosphatase in C. glutamicum.     

Effects of anisotonicity on pentose-phosphate pathway,oxidized glutathione release and t-butylhydroperoxide-induced oxidative stress in the perfused liver of air-breathing catfish,<Emphasis Type="Italic">Clarias batrachus</Emphasis>

Both hypotonic exposure (185 mOsmol/l) and infusion of glutamine plus glycine (2 mmol/l each) along with the isotonic medium caused a significant increase of¹⁴CO₂ production from [1-¹⁴C]glucose by 110 and 70%, respectively, from the basal level of 18.4 ± 1.2 nmol/g liver/min from the perfused liver ofClarias batrachus. Conversely, hypertonic exposure (345 mOsmol/l) caused significant decrease of¹⁴CO₂ production from [1-¹⁴C]glucose by 34%.¹⁴CO₂ production from [6-¹⁴C]glucose was largely unaffected by anisotonicity. The steady-state release of oxidized glutathione (GSSG) into bile was 1.18 ±0.09 nmol/g liver/min, which was reduced significantly by 36% and 34%, respectively, during hypotonic exposure and amino acid-induced cell swelling, and increased by 34% during hypertonic exposure. The effects of anisotonicity on¹⁴CO₂ production from [1-¹⁴C]glucose and biliary GSSG release were also observed in the presence of t-butylhydroperoxide (50 (Amol/1). The oxidative stress-induced cell injury, caused due to infusion of t-butylhydroperoxide, was measured as the amount of lactate dehydrogenase (LDH) leakage into the effluent from the perfused liver; this was found to be affected by anisotonicity. Hypotonic exposure caused significant decrease of LDH release and hypertonic exposure caused significant increase of LDH release from the perfused liver. The data suggest that hypotonically-induced as well as amino acid-induced cell swelling stimulates flux through the pentose-phosphate pathway and decreases loss of GSSG under condition of mild oxidative stress; hypotonically swollen cells are less prone to hydroperoxide-induced LDH release than hypertonically shrunken cells, thus suggesting that cell swelling may exert beneficial effects during early stages of oxidative cell injury probably due to swelling-induced alterations in hepatic metabolism.     

Evidence of an association between poly(3-hydroxybutyrate) accumulation and phosphotransbutyrylase expression in<Emphasis Type="Italic"> Bacillus megaterium</Emphasis>

Molecular analysis of a genomic region of Bacillus megaterium, a polyhydroxybutyrate (PHB)-producing microorganism, revealed the presence of a gene coding for the enzyme phosphotransbutyrylase (Ptb). Enzyme activity was measured throughout the different growth phases of B. megaterium and was found to correlate with PHB accumulation during the late-exponential growth phase. Ptb expression was repressed by glucose and activated by the branched amino acids isoleucine and valine. Overexpression of Act_Bm, a ⁵⁴ regulator from B. megaterium whose gene is located upstream from ptb, caused an increase in Ptb activity and PHB accumulation in B. megaterium.     

Detection of<Emphasis Type="Italic">pap</Emphasis>-,<Emphasis Type="Italic">sfa</Emphasis>- and<Emphasis Type="Italic">afa</Emphasis>-specific DNA sequences in<Emphasis Type="Italic">Escherichia coli</Emphasis> strains isolated from extraintestinal material

P-fimbriae, S-fimbriae and AFA-adhesins are virulence factors responsible for adherence ofEscherichia coli strains to extraintestinal host-cell surface. Detection ofpap-,sfa- andafa-specific sequences performed by PCR revealed 74%pap ⁺, 65%sfa ⁺, and 8.3%afa ⁺ strains in a group of 84 extraintestialE. coli isolates. Detection in a group of fecal strains showed 29%pap ⁺, 21%sfa ⁺ and 4%afa ⁺ strains.pap together withsfa were found as the most frequent combination (56%) among extraintestinal isolates probably due to localization ofpap-andsfa-operons on a common pathogenicity island. The occurrence ofafa-specific sequence among 56 urine strains was 11%, although noafa ⁺ strain was detected among 28 gynecological isolates. No strains with detected adhesin operons were found among twenty (24%) extraintestinalE. coli strains.     

Formation of bound gibberellins inPharbitis nil

Summary Developing seeds ofPharbitis nil accumulate free as well as bound gibberellins until a maximum level is reached at approximately 25 days after anthesis. Seeds from CCC-treated parent plants have a strongly reduced level of free as well as bound gibberellins. When different spray reagents were used it was found that trichloroacetic acid in particular was suitable to locate non-hydrolysed bound GA fractions on thin-layer plates. Chromatography showed two major bound GA fractions, determined with spray reagents as well as by means of hydrolysis.³H-GA₁ applied to youngPharbitis plants was converted to two water-soluble compounds present in the aqueous phase. The rate of conversion was significantly enhanced when³H-GA₁ and¹⁴C-glucose were applied to the same plants. Chromatography indicated that one of the conversion products of³H-GA₁ became at least partly associated with the applied¹⁴C-glucose (or its products). This suggestion was also supported by the fact that mild acid hydrolysis of the aqueous fraction resulted in the reappearance of³H-GA₁ and a conversion product of³H-GA₁, including a¹⁴C-radioactivity peak cochromatographing with¹⁴C-glucose. However, the conversion products obtained with³H-GA₁ applied to plants appeared to be chromatographycally different from any of the bound-GA fraction established by means of hydrolysis or spray reagents in developing seeds.Abbreviation GA(s) gibberellin(s).     

Slow low-threshold potassium current inHelix pomatia neurons

A low-threshold outward current was studied in the neurons ofHelix pomatia at –70 to –30 mV using a two-electrode voltage clamp technique. In addition to the well-known A current (I _A), a slower outward current calledI _As (slow) was revealed. Activation and inactivation times ofI _As at –40 mV ranged from 90 to 120 msec and from 3 to 5 sec, respectively. The current recovered within 2 to 5 sec after inactivation at –120 mV. Analysis of changes in the reversal potential ofI _As caused by an increase in external potassium concentration suggests a potassium origin forI _As. The curves ofI _As stationary activation and inactivation fit the Boltzmann equation. Deriving from an activation curve, the activation potential for a half-maximum current,, is –40 mV, and the slope factor,k, is –9.8 mV, while those values for the inactivation curve are –84 mV (a half-maximum inactivation) and 7.5 mV.I _As is blocked by 4-aminopyridine (1–30 µM), tetraethylammonium (1 mM), and Ba²⁺ (1 mM), but is resistant to Cs⁺ (1 mM). PeakI _As is not affected either by substitution of external Ca²⁺ for Mg²⁺ or by application of Cd²⁺ (0.5–1.0 mM). The results suggest that activation ofI _As does not require Ca²⁺ entry into the cell.Neirofiziologiya/Neurophysiology, Vol. 25, No. 6, pp. 427–432, November–December, 1993.     

A chitinase with high activity toward partially<Emphasis Type="Italic"> N</Emphasis>-acetylated chitosan from a new,moderately thermophilic,chitin-degrading bacterium,<Emphasis Type="Italic"> Ralstonia</Emphasis> sp. A-471

A moderately thermophilic bacterium, strain A-471, capable of degrading chitin was isolated from a composting system of chitin-containing waste. Analysis of the 16S rDNA sequence revealed that the bacterium belongs to the genus Ralstonia. A thermostable chitinase A (Ra-ChiA) was purified from culture fluid of the bacterium grown in colloidal chitin medium. Purification of the enzyme was achieved mainly by exploiting its binding to the colloidal chitin. The molecular mass of the enzyme was estimated to be 70 kDa and the isoelectric point approximately 4.7. N-terminal amino acid sequencing revealed a sequence of ADPYLKVAYYP, which had high homology (66% identity) with that of chitinase A1 from Bacillus circulans WL-12. The pH and temperature optima were determined to be 5.0 and 70°C, respectively. The enzyme was classified as a retaining glycosyl hydrolase and was most active against partially N-acetylated chitosans. Its activities towards the partially N-acetylated chitosans, i.e. chitosan 7B, chitosan 8B, and chitosan 9B, were about 11-fold, 9-fold, and 5-fold higher than towards colloidal chitin, respectively. Ra-ChiA cleaved (GlcNAc)₆ almost exclusively into (GlcNAc)_2. Activation of Ra-ChiA was observed by the addition of 1 mM Cu²⁺, Mn²⁺, Ca²⁺_, or Mg²⁺. Degradation of the partially N-acetylated chitosan produced oligosaccharides with a degree of polymerization ranging from 1–8; these are products that offer potential application for functional oligosaccharide production.     

Effect of growth rate on the production of<Emphasis Type="SmallCaps">l</Emphasis>-proline in the fed-batch culture of<Emphasis Type="Italic">Corynebacterium acetoacidophilum</Emphasis>

Corynebacterium acetoacidophilum RYU3161 was cultivated in al-histidine-limited fed-batch culture. To investigate the effect of cell growth on thel-proline production, 5l fed-batch culture was performed using an exponential feeding rate to obtain the specific growth rates (μ) of 0.04, 0.06, 0.08, and 0.1 h⁻¹. The results show that the highest production ofl-proline was obtained at μ=0.04 h⁻¹. The specificl-proline production rate (Q_p) increased proportionally as a function of the specific growth rate, but decreased after it revealed the maximum value at μ=0.08 h⁻¹. Thus, the highest productivity ofl-proline was 1.66 g L⁻¹ h⁻¹ at μ=0.08 h⁻¹. The results show that the production of L-proline inC. acetoacidophilum RYU3161 has mixed growth-associated characteristics.     

Cytological and genetical studies of the hybrid ofGossypium herbaceum L. andG. triphyllum Hoch

Cytological and genetical studies are reported on the hybrid and later generations ofGossypium herbaceum (A₁ genome) xG. triphyllum (Hg genome). Chromosome pairing between the two genomes was high, and their chromosomes are considered, with minor exceptions, to be strueturally similar. Studies of the F₁ and segregating families showed thatG. triphyllum carries the complementary factorsR _inf2 ^supΘS R _infa ^supGO for petal spot,Y _a(Y_b) Y _infc ^supP for cream petal,pa for cream pollen, andY _ap for depression of yellow petal pigment. Leaf ahape ofG. triphyllum was dominant to the leaf shape ofG. herbaceum. The blue petal color ofG. triphyllum was recovered only in the backeross of the F₁ to this species. Contribution from the Agricultural Experiment Stations of Arizona and Texas. Part of this work was done under Regional Research Project S-1 of the Hatch Act (Amended). 1. Address of first author; 2. Address of second author.