Growth-saturation in vitro of Salmonella flagella

At physiological ionic strength and pH, short fragments of Salmonella flagella (seeds) grow longer in the presence of monomeric flagellin and there exists a one-to-one correspondence between the seeds and fully grown filaments (Asakura et al., 1964). In this study it was shown that when monomer and seed derived from a preparation of flagella (strain SJ25) were mixed in a protein ratio r larger than 20, the filaments stopped growing or became inactive for a long period of time, and the average length of inactive filaments was independent of the value of r. The phenomenon was called growth-saturation. The antibody-labelling technique (Asakura et al., 1968) made it possible to show that, though active filaments having equal lengths grew at various rates ranging between 0 and 0.16 μm/min, the average value of growth rate depended little on length. On the other hand, it was found that the proportion of inactive filament in the total filament increased rapidly as the value of r was increased continuously from 0 to 10. The dependence of the proportion of inactive filament on r suggested that filaments became inactive with a probability independent of their length. The rate of inactivation (or the probability with which a filament becomes inactive during growth by a unit length) had various values when different preparations of flagella were used as starting materials. The distribution of length for an assembly of inactive filaments was determined by low-magnification electron microscopy. The result could be approximated by an exponential distribution: the number-average length was 4.54 μm and the rate of inactivation was 0.224 μm^?1.     

Microoxic-Anoxic Niche of Beggiatoa spp.: Microelectrode Survey of Marine and Freshwater Strains

Beggiatoa spp. grow optimally in media containing opposed gradients of oxygen and soluble sulfide, although some strains also require an organic substrate. By using microelectrodes, we characterized oxygen and sulfide gradients during their initial development in uninoculated media and in cultures of marine and freshwater strains. In gradient media, Beggiatoa strains always grew some distance below the air/agar interface as a dense “plate” of constantly gliding filaments with sharply demarcated upper and lower boundaries. Within established plates, the maximum oxygen partial pressure was 0.6 to 6.0% of air saturation and not significantly lower if filaments were fixing nitrogen. Oxygen penetrated only 100 to 300 μm into the plate, and the anoxic fraction increased from less than 10% to approximately 90% during later stages of growth. For lithoautotrophically grown marine strains, the linearity of the oxygen profile above the plate plus its drop to zero therein indicated that oxygen uptake for the entire tube occurred only within the Beggiatoa plate. Consequently, oxygen consumption could be predicted solely from the distance between the air/agar interface and the top of a plate, given the diffusion coefficient for oxygen. By contrast, for freshwater strains grown heterotrophically (with sulfide also in the medium), oxygen profiles were frequently nonlinear because of nonbiological reaction with sulfide which had diffused past the aggregated filaments. For all strains tested, microoxic aggregation also occurred in the absence of sulfide, apparently reflecting a step-up phobic response to oxygen.     

吉林省蓝藻门真枝藻属三新种

报道了采自吉林省的蓝藻门真枝藻属三新种：波纹真枝藻,拟小真枝藻,悦目真枝藻。波纹真枝藻丝体边缘常呈波纹状,主丝体宽 80～100 μm;拟小真枝藻主丝体宽 60～80 μm,分枝宽 30～45 μm,其胶被幼时黄褐色,成熟后无色;悦目真枝藻的匍匐丝体由数条丝体通过侧面粘合在一起,每条丝体宽 15～26 μm。     

Formation of Filaments by Pseudomonas putida

When Pseudomonas putida 40 was grown on a variety of liquid media in which oxygen became a limiting factor during growth, the latter stages of growth involved the elongation of cells without septation, which can result in the complete filamentation of the culture (up to several hundred micrometers long). The filaments appeared to consist of a chain of protoplasts within a common sacculus. Later these filaments were capable of a rapid fragmentation by septation to give a population of ordinary rods with a corresponding increase in the number of viable particles but no appreciable change in total bacterial mass. Filamentation did not occur if slow growth rates were maintained by restriction of oxygen availability from the beginning of growth. In complex media filaments were not formed during growth on 1% peptone alone, but the addition of 0.1 M phosphate or 6.6 × 10⁻⁴ M EDTA induced extensive filamentation that was reversed by the addition of 6.6 × 10⁻⁴ M Mg²⁺. In minimal media a much higher Mg²⁺ concentration than that required for active growth or present in the complex media was usually required for filamentation. A very narrow range of Mg²⁺ concentration promoted filamentation, and this optimum differed markedly depending on the carbon source used. Other medium variations which influenced the level of filamentation are reported. We found that most strains of P. putida (including the neotype strain) and P. fluorescens gave filaments under the conditions developed with strain 40, whereas several strains of P. aeruginosa failed to give filaments on the same media.     

An evaluation of respiration chain-associated functions during initiation of germination of Bacillus megaterium spores

In Bacillus megaterium QM B1551, spore germination could be initiated by glucose in the absence of detectable oxygen consumption, ATP synthesis or a pH decrease in the external media, suggesting that none of those reactions were mandatory. In addition, initiation of germination was insensitive to a variety of inhibitors of energy production or protonmotive force uncouplers. Therefore the respiratory chain-associated functions are not prerequisites for initiation of germination but these functions may be necessary to drive energy-dependent transport systems and other biosynthetic reactions during outgrowth.     

Treadmilling of actin at physiological salt concentrations: An analysis of the critical concentrations of actin filaments

Treadmilling of actin was investigated at physiological salt concentrations (100 mm-KCl, 0.5 to 2.0 mm-MgCl₂, 200 μm-ethyleneglycol-bis(β-aminoethyl ether)N,N′-tetraacetic acid or 50 μm-CaCl₂ at 37 °C. The concentration at which monomers bind to the lengthening end of filaments with the same rate as subunits are released (low critical concentration c₁ was determined by mixing unmodified actin filaments with various concentrations of monomeric actin labeled with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole. Above a monomeric actin concentration of about 0.12 μm, incorporation of actin molecules into filaments was detected, whereas below this concentration no incorporation was found (c₁ = 0.12 μm). Combination of various concentrations of labeled monomers with labeled filaments permitted determination of the net critical concentration ($\text{c}{}_1$) at which filaments lengthen at one end with the same rate as they shorten at the other end ($\text{c}{}_1\text{= 0.16}\text{μm}$). A lower limit of the high critical concentration at the shortening end (c_h) was estimated by measuring the release of subunits from labeled filaments in the presence of various concentrations of unlabeled monomers (c_h >0.5 μm). The differences in the three critical concentrations demonstrate that under physiological conditions actin filaments lengthen at one end by, on the average, one subunit during the time that four association reactions take place at the two ends (efficiency parameters $\text{s =}\text{1}\text{4}$). The small difference between the low and the net critical concentration suggests that the rates of both association and dissociation are considerably greater at the lengthening end than at the shortening end of actin filaments.     

Turnover of murein in cellular and filamentous populations ofBacillus megaterium

Bacillus megaterium grows in the form of filaments at temperatures above 45°C. The rate of turnover of the cell wall begins to decrease gradually under these conditions. At the same time sensitivity of the filamentous forms to lysozyme decreases. Filaments outgrown at 48°C retain the decreased rate of turnover of the cell wall for a certain time after transfer to 30°C, in spite of the fact that septa are formed and filaments are converted to cells. However, a population incubated longer than 2 h at 48°C often ceases to grow and the growth is not restored even after transfer to 30°C. Three clones of the asporogenic strainBacillus megaterium KM differing somewhat in their ability to form filaments at 35°C differ mutually also in the rate of turnover of the cell wall. However, the decreased rate of the turnover cannot be unambiguously correlated with the increased tendency to form filaments.     

Taxonomic study of the genus Spongomorpha (Acrosiphoniales,Chlorophyta) in Japan. I. Spongomorpha spiralis*

The morphology, life history, and the geographical distribution of Spongomorpha spiralis Sakai in Hokkaido, Japan, was studied. The thallus is characterized by its digitate tufts (bundles) of slender filaments with hooked branchlets. The diameter of the filaments is usually 20-50 μm in the basal portion, 50-130 (70-110) μm in the middle portion of main axes, and 30-150 μm in the upper portion. The diameter of the middle portion of the main axes varies from locality to locality. At Muroran, for example, the range is 70-130 μm (average approximately 100 μm), while at other localities it is 50–100 μm (average approximately 70 μm). The diameter of filaments in the upper portion decreases toward the end of the growing season. The cells are multinucleate with four chromosomes in each nucleus of the haploid plant. The manner of cell division is identical to the process reported previously for the Spongomorpha-Acrosiphonia complex. Sexual reproduction is isogamous with anteriorly biflagellate gametes. Plants are unisexual. The life history involves an alternation of heteromorphic generations: the gametophytic phase is a macroscopic, filamentous thallus and the sporophytic phase is a microscopic, ellipsoidal or club-shaped cell. Optimal culture condition for growth and reproduction of both stages was 5°C and long daylength. The gametophyte developed abnormally at 15°C. The sporophyte developed normally at 15°C, but did not produce zoospores.     

Early Cretaceous record of microboring organisms in skeletons of growing corals

Ko?odziej, B., Golubic, S., Bucur, I.I., Radtke, G. & Tribollet, A. 2011: Early Cretaceous record of microboring organisms in skeletons of growing corals. Lethaia, Vol. 45, pp. 34–45. A spectacularly preserved assemblage of microbial euendoliths, penetrating into skeletons of growing scleractinian corals, has been recognized in Early Aptian (Early Cretaceous) reef limestone of the Rar?u Mountains (East Carpathians, NE Romania). Microboring euendolithic filaments were found in five coral colonies of the suborder Microsolenina. They remained in part well‐preserved, often impregnated with iron oxides, which made them visible even in strongly recrystallized parts of coral skeletons. Filaments of a wide range of sizes (2–40 μm in diameter) were concentrated within medium parts of coral septa, oriented along the septa in the direction of the coral growth. The larger filaments were tubular, occurring in bundles and branched into finer, often tapering branches. Their behaviour and organization were quite similar to the modern euendolithic siphonalean chlorophyte Ostreobium. Filament diameters exceeded those reported for the modern species, but covered a similarly wide size range. Narrower frequently branching filaments, 4–8 μm in diameter, resemble distal branching patterns of modern Ostreobium quekettii. Some very thin filaments (ca. 1–2 μm) observed within skeleton or inside the large tubular filaments, sometimes associated with globular swellings, may represent euendolithic fungi. The recrystallization of coral skeleton had limited effect on preservation of euendoliths due to their impregnation with iron oxides; microbial euendoliths were subjected to different taphonomic changes. □Chlorophytes, Early Cretaceous, fungi, microbial euendoliths, Romania, scleractinian corals.     

Influence of oxygen transfer rate on the accumulation of poly(3-hydroxybutyrate) by Bacillus megaterium

Poly(3-hydroxybutyrate)—P(3HB)—is a natural biodegradable polyester synthesized by several bacteria, produced from renewable resources. The effects of oxygen transfer rate on the intracellular accumulation of P(3HB) was evaluated, aiming at increasing P(3HB) synthesized by Bacillus megaterium DSM 32^T in bioreactor batch cultures. Bench-scale bioreactor cultivations were performed under different volumetric oxygen mass transfer coefficients, k_La, setting stirrer speed on specified values. The results of this work show that oxygen transfer is a key factor on P(3HB) accumulation by B. megaterium, increasing the P(3HB) intracellular mass fraction from 39% to 62% of CDW at k_La condition of 0.006 s^?1.     

Cometoides pechumani sp. n. (Protozoa: Eugregarinida), a gregarine parasite of salt marsh deerflies (Diptera: Tabanidae)

Cometoides pechumani sp. n. is described from larvae and adults of Chrysops fuliginosus and from a pupa of C. atlanticus. Stages of the gregarine were found in the fore-, mid-, and hindguts. The globular to spherical epimerite possessed at least 14 long filaments. The cephalic sporadins were elongate, cylindrical, and tapered. Mean length was 998 μm. Mean diameters of the gametocysts were 519.8 × 558 μm. Oocysts (spores) are hexagonal in outline with polar spines and two bands of equatorial spines. Their mean length and width were 7.35 × 4.32 μm. Incidence of infection of field-collected C. fuliginosus larvae was greatest in summer when rates were as high as 89%. Infection during winter ranged from 30 to 58%. Incidence of infection of adult C. fuliginosus never exceeded 7%.     

Studies on bacterial cell wall inhibitors: II. Inhibition of peptidoglycan synthesis in vivo and in vitro by amphomycin

Amphomycin has been reported by the present authors to be a selective inhibitor of cell wall peptidoglycan synthesis in Bacillus cereus T (ōmura, S., Tanaka, H., Shinohara, M., ōiwa, R. and Hata, T. (1975) Chemotherapy 5, 365–369). Investigations were carried out to clarify the target of amphomycin.Amphomycin (10 μg/ml) lysed growing cells of B. cereus T, and inhibited peptidoglycan synthesis, accompanied by accumulation of uridine diphosphate-N-acetylmuramyl (UDP-MurNAc) peptides. The nucleotide precursors that accumulated in cells of Staphylococcus aureus FDA 209P in the presence of amphomycin were identified as UDP-MurNAc-L-Ala-D-Glu-L-Lys-D-Ala-D-Ala, UDP-MurNAc-L-Ala and UDP-MurNAc. In the experiments using a particulate enzyme system of Bacillus megaterium KM, amphomycin inhibited the polymerization of UDP-MurNAc-L-Ala-D-Glu-meso-diaminopimelic acid-D-Ala-D-Ala (UDP-MurNAc-pentapeptide) and UDP-N-acetylglucosamine, and also inhibited the formation of lipid intermediates, but did not inhibit the cross-linking, the last step of peptidoglycan synthesis. Unlike bacitracin, amphomycin did not lyse protoplasts of B. megaterium KM.We conclude that the site of action of amphomycin is the formation of MurNAc-(pentapeptide)-P-P-lipid from MurNAc-pentapeptide and undecaprenol (lipid) phosphate.     

Actin filaments responsible for the location of the nucleus in the lentil statocyte are sensitive to gravity

The location of the nucleus in statocytes of lentil roots grown: I), at 1 g on the ground, 2), on a 1 g centrifuge in space, 3), in simulated microgravity on a slowly rotating clinostat (0.9 rmp) 4), in microgravity in space was investigated and statistically evaluated. In cells differentiated at 1 g on the ground, the nuclear membrane was almost in contact with the plasmalemma lining the proximal cell wall, whereas in statocytes of roots grown on the clinostat there was a distance of 0.47 μm horizontal clinorotation) and of 0.76 μm vertical clinorotation) between these membranes. However, in microgravity the nucleus was the most displaced, 0.87 μm from the proximal cell wall. Centrifugation of vertically grown roots in the root-tip direction showed that the threshold of centrifugal force to detach all nuclei from the proximal cell wall was about 40 g. In statocytes developed in the presence of cytochalasin B at 1 g the nuclei were sedimented on the amyloplasts at the distal cell pole, demonstrating that the location of the nucleus depends on actin filaments. The results obtained are in agreement with the hypothesis that gravity causes a tension of actin filaments and that this part of the cytoskeleton undergoes a relaxation in microgravity.     

Improved procedure for X-ray photoelectron spectroscopy of selenium-glutathione peroxidase and application to the rat liver enzyme.

Purified rat liver soluble glutathione peroxidase, with a specific activity of 280 μmol of NADPH oxidized/min/mg of protein, was studied by X-ray photoelectron spectroscopy. The sampling technique developed required only 20–25 μg of protein for each sample. Selenium 3d electron signals were found in the 55.0 ± 0.3 eV region. The spectrum at the 55 eV region was free from interfering magnesium and iron. The selenium 3d electron signals observed gave evidence that selenium in glutathione peroxidase is not bound to oxygen.     

Experimentally induced in vivo increase in size of calcium citrate crystals in praying mantids

Regular, membrane-bound crystals of calcium citrate are secreted by a special gland in adult female Sphodromantis lineola, and reach a size of ca. 10 μm long by ca. 5 μm wide and ca. 4 μm high before they are extruded into the oötheca at each oviposition. Substantially larger, but still regular, crystals were obtained from the glands of insects which had been injected with laboratory prepared calcium or magnesium citrate, and from glands which had been artificially prevented from extruding their contents for extended periods (e.g. up to 70 days). Enlarged crystals retain the membranes which are probably responsible for maintaining the characteristic trapeziform shape.     

The role of bacteria in the metal tolerance of the fouling diatom Amphora coffeaeformis Ag.

Components of “spent” axenic and non-axenic Amphora coffeaeformis Ag. culture media were tested for their effect on copper and tributyltin tolerance in axenic A. coffeaeformis. Growth of such algal cultures in the presence of either toxin was enhanced by the addition of enriched “spent” medium from exponentially growing non-axenic cultures. This response was seen whether or not the bacteria had been removed. It appears that bacteria or bacteria-algal interactions produce some soluble (<0.2 μm) factor which either decreases the toxicity of copper and tributyltinfluoride (TBTF) or increases the tolerance of A. coffeaeformis to these toxins.     

Ortholinea scatophagi (Myxosporea: Ortholineidae), a novel myxosporean infecting the spotted scat,Scatophagus argus (Linnaeus 1766) from southwest coast of India

A new species of myxosporean, Ortholinea scatophagi n. sp. infecting the urinary bladder of the spotted scat, Scatophagus argus (Linnaeus 1766) is described. O. scatophagi n. sp. is characterized by spherical myxospores with a slightly flattened anterior end and equal spore valves with extra sutural ridges on its surface; measured 7.34 ± 0.67 μm in length, 6.90 ± 0.71 μm in width and 6.48 ± 0.37 μm in thickness. Two polar capsules, equal, spherical to oval in shape, arranged diametrically opposite and measured 2.59 ± 0.42 μm in length and 2.24 ± 0.35 μm in width. Polar filaments, 21.84 ± 2.86 μm long, with four to five coils. Scanning electron microscopy revealed the presence of extra sutural ridges on spore surface. Pansporoblasts spherical to irregular in shape, measured 31.08 ± 2.67 μm in length and 13.88 ± 5.40 μm in width; Monosporic, disporic and polysporic plasmodial stages were observed; plasmodia spherical or irregular in shape with granular cytoplasm containing refractile granules. The species was compared with 23 existing nominal species of Ortholinea, based on morphology and morphometry. Molecular analysis resulted in a 1773 bp long SSU rDNA sequence (GenBank accession number MN 310514). In phylogenetic analyses the present parasite clustered with other members of Ortholinea, under the freshwater urinary clade. Considering the morphologic, morphometric and molecular differences with previously described species of Ortholinea, and differences in host and geographic locations, the present species is treated as new and the name Ortholinea scatophagi n. sp.is proposed.     

Characterization of a non-indexible equatorial x-ray reflection from frog sartorius muscle.

X-ray equatorial reflections from frog sartorius muscle were studied using a position sensitive detector. A weak reflection appeared between the 10 and 11 peaks which did not index on the hexagonal filament lattice. This reflection, first reported by Elliott et al. (1967), was further characterized. The spacing of the reflection varied in direct proportion to that of the 10 peaks for sarcomere lengths between 2·0 μm and 3·0 μm. Its intensity appeared relatively insensitive to length changes. Optical diffraction patterns from electron micrographs of oblique sections through muscle gave ratios for the spacings of the myosin filaments and the Z-disc lattice that correlated very closely with the X-ray results. It is suggested that the Z-disc structure is the major source of this nonindexible reflection.     

Studies on N-limited growth of diatoms in dialysis culture

N-limited growth of Skeletonema costatum (Grev.) Cleve in dialysis culture has been studied. The division rate of exponentially growing cells was independent of the nitrate concentration in the growth medium in the range from 886 down to 0.25 μM N-salt, while no growth beyond one division took place in cultures to which no nitrogen salt was added. The half saturation constant, K₃, for growth must, therefore, be in the range 0–0.13 μM, provided the growth-nutrient relationship is hyperbolic for S. costatum.Contrary to growth rate, cellular chlorophyll and protein were markedly reduced in media poor in nitrogen salts. A dialysis culture chamber was used to demonstrate that the measurement of half saturation constants for S. costatum was influenced by stirring, the stirred culture growing almost twice as fast as the unstirred control under identical conditions. The ability of diatoms to grow rapidly at low nitrogen levels was used to remove nutrients from sewage enriched media. Removal efficiencies corresponding to 80 and 90 % were obtained for nitrate and ammonia, respectively, using the diatom Phaeodactylum tricornutum Bohlin. It was found that both this diatom and S. costatum as well as Thalassiosira pseudonana Hust (Hasle) tolerated ammonia up to at least 450 μM with no deleterious effects on growth rate.     

Pulse radiolysis studies of antitumor quinones: Radical lifetimes,reactivity with oxygen,and one-electron reduction potentials

The formation of semiquinone free radicals from antitumor drugs has been studied by pulse radiolysis. The semiquinone free radicals are reactive and have short half-lives in aqueous media under anaerobic conditions. The half-lives of the radicals formed from adriamycin, mitomycin C, and 2,5-diaziridinyl-3,6-bis(carboethoxy)amine-1,4-benzoquinone (AZQ) are 50,100, and 200 μs, respectively. The mean diffusion distance of the semiquinone free radical is less than 0.6 μm. In the presence of molecular oxygen the half-life of the semiquinone free radical is shortened. Adriamycin semiquinone reacts rapidly with oxygen, k = 4.4 × 10⁷m^?1s^?1. In air-saturated buffer the half-life of adriamycin semiquinone radical can be calculated to be 8 μs with a mean diffusion distance of less than 0.1 μm. If the half-lives in buffer are comparable to those within a cell, semiquinone free radicals must be generated close to the site at which they produce a biological effect. One-electron reduction potentials (E₇¹) were determined and were AZQ, ?168 mV, adrenochrome, ?253 mV, mitomycin C, ?271 mV, adriamycin, ?292 mV, daunomycin, ?305 mV, and anthracenedione, ?348 mV. Enzymatic one-electron reduction of these antitumor quinones by NADPH-cytochrome P-450 reductase increased at more positive values of quinone E₇¹.