Semper's (zoanthid) larvae: pelagic life,parentage and other problems

Semper's larvae were obtained from <300 out of 1800 plankton tows taken in the world's oceans (1964–1993). Zoanthellae (larvae of Sphenopidae) occurred at 217 stations and zoanthinae (larvae of Zoanthidae) at 86, the two larval types showing distributions clearly delimited by a minimum sea temperature (22 °C for zoanthellae, 18 °C for zoanthinae; a statistically significant difference, P<0.001). Length of formalin-fixed zoanthellae was 2–8.6 mm and of zoanthinae 1.5–5.9 mm. Endodermal zooxanthellae were present in 9/24 zoanthinae but in no zoanthellae (of 19). Three larvae contained an endo-commensal/parasitic amphipod. Septa were externally visible in larger zoanthinae and were counted in transverse sections of other larvae, a majority of which (both kinds) had 12 septa, the normal maximum. The pattern was brachycnemic in 40/43 larvae and anomalous (but non-macrocnemic) in three. If macrocnemic genera reproduce by Semper's larvae, they should have been represented in such a large sample. The distribution of adult Epizoanthus was examined: many species are deep sea (recorded down to 5000 m) but shallow-water species are relatively plentiful in, for example, the Adriatic and North Seas. No Semper's larva has ever been recorded from either. Some Parazoanthus species also occur in shallow water, especially associated with western Atlantic reef sponges. If they produce Semper's larvae, these have never been found. It is probable that macrocnemic zoanthids settle from planulae that do not develop into recognizable zoanthellae or zoanthinae.     

Effect of temperature on infection, development and reproduction of the parasitic nematode Thripinema nicklewoodi in Frankliniella occidentalis

The parasitic nematodeThripinema nicklewoodi Siddiqi (Tylenchida:Allantonematidae) is currently underinvestigation for use in inoculative releasestrategies against western flower thrips (WFT),Frankliniella occidentalis Pergande(Thysanoptera: Thripidae) infesting greenhousefloricultural crops. The aim was to determinewhether temperatures within greenhouses wouldpermit the establishment of T.nicklewoodi. The abilities of T.nicklewoodi to infect, develop and reproducein WFT were assessed under a range of constantand fluctuating temperatures in the laboratory.At constant temperatures, T. nicklewoodiinfected WFT over the range of 1–30 °C,although the temperature-related infectionprofile followed an asymmetric distributionaround an optimum 20 °C (80%infection). The lower and upper thresholds forT. nicklewoodi in vivo development andreproduction were higher than for infection, at10 °C and 35 °C, respectively.Climate data recorded over 1999–2000 in acommercial greenhouse (Texas) revealed atemperature range of 15 °C to31 °C from early March through mid June,when WFT were most abundant. While low(nighttime) greenhouse temperatures areconducive for T. nicklewoodi, upperdaytime temperatures are close to the upperthreshold for infection and may reducereproductive output. However, fluctuatingtemperature bioassays in the laboratorydemonstrated that T. nicklewoodimaintained separately at the upper thresholdtemperatures for infection (30 °C) anddevelopment (35 °C) readily infected anddeveloped in WFT when they were allowedintermittent (10 h daily) exposure to apermissive temperature in the range10–20 °C. Drawing on the results, thediurnal temperature-fluctuations of variousgreenhouses growing ornamentals would permitthe establishment of T. nicklewoodi.     

The Effect of Salicylic Acid on Peroxidase Activity in Wheat Calli Cocultured with the Bunt Pathogen Tilletia caries

The effect of salicylic acid (SA) on peroxidase activity in wheat (Triticum aestivum L.) calli cocultured with the bunt pathogen Tilletia caries was studied. Fungal infection was shown to activate cytoplasmic peroxidase. SA suppressed total peroxidase activity but did not inhibit the peroxidase with pI 9.8. A novel chitin-specific peroxidase with pI 3.5 appeared after the SA treatment. The infection of SA-treated cells with Tilletia caries activated the isoenzymes with pI 3.5, 4.8, and 7.5 and stimulated their secretion into the culture medium. The ability of SA to control wheat peroxidase activity during pathogenesis is discussed. The important role of this control in plant defense responses to the bunt pathogen is emphasized.     

Indole-3-acetic acid content and glutamine synthetase activity in the pericarp, and peroxidase activity and isoenzymes in the meso- and exocarp of growing peach fruits

The indole-3-acetic acid (IAA) content in peach pericarp (Prunus persica L. Batsch cv. Merry) was highest at early stage I of development (200 ng/g fresh wt), decreased to the lowest level during stage II, and rose again at stage III to 60–70 ng/g fresh wt. High activity of glutamine synthetase was found in the pericarp during stage I. The soluble peroxidase activity was highest in the meso- and exocarp at stage II, and isoenzymatic changes in this fraction corresponded to the transition from cationic isoenzymes, predominant at stage I, to anionic isoenzymes at stage III. The ionically bound peroxidase activity in these tissues was highest at stage I. The three developmental stages showed marked differences in auxin content and enzyme activities; for peroxidases these changes reflect a developmental expression pattern for the isoenzymes.     

Flash Heating on the Early Earth

It has been suggested that very large impact events ( 500 km diameter impactors) sterilized the surface of the young Earth by producing enough rock vapor to boil the oceans. Here, we consider surface heating due to smaller impactors, and demonstrate that surface temperatures conducive to organic synthesis resulted. In particular, we focus on the synthesis of thermal peptides. Previously, laboratory experiments have demonstrated that dry heating a mixture of amino acids containing excess Asp, Glu, or Lys to temperatures 170 °C for 2 hours yields polypeptides. It has been argued that such temperature conditions would not have been available on the early Earth. Here we demonstrate, by analogy with the K/T impact, that the requisite temperatures are achieved on sand surfaces during the atmospheric reentry of fine ejecta particles produced by impacts of bolides 10–20 km in diameter, assuming 1 – 100 PAL CO2. Impactors of this size struck the Earth with a frequency of 1 per 104 – 105 y at 4.2 Ga. Smaller bolides produced negligible global surface heating, whereas bolides > 30 km in diameter yielded solid surface temperatures > 1000 K , high enough to pyrolyze amino acids and other organic compounds. Thus, peptide formation would have occurred globally for a relatively narrow range of bolide sizes.     

Summer egg production rates of paracalanid copepods in subtropical waters adjacent to Australia's North West Cape

The biological oceanography of waters adjacent to Australia's North West Cape (21° 49 S, 114° 14 E) was studied during the austral summers of 1997/98 and 1998/99. We measured egg production rate (EPR) by the small paracalanid copepods that dominated the calanoid community. Bottle incubation experiments were conducted at a shallow (20 m) station in the mouth of Exmouth Gulf, and at a shelf-break station (80 m). In 1997/98, we measured EPR by Paracalanus aculeatus, P. indicus, Acrocalanus gracilis and Bestiolina similis, but in 1998/99, we concentrated on P. indicus. Maximal observed EPRs by Paracalanus and Acrocalanus species were 30 eggs female^–1 d^–1, but B. similis attained only 17 eggs female^–1 d^–1. Sporadic measurements of EPR by P. aculeatus minor (maximum 4 eggs female^–1 d^–1) and Parvocalanus crassirostris ( 9 eggs female^–1 d^–1) were also made. However, maximal EPRs were seldom achieved and were often less than 10 eggs female^–1 d^–1. There was no difference between EPR of either P. indicus or B. similis in 1997/98 and 1998/99, despite differences in temperature. Trophic resources severely limit copepod egg production in this area. We suggest that variability and skewness of egg production data derived from individual incubations may be used to judge the degree of food limitation of the population and the variability in feeding success between individuals. The dominance of small copepods and the invariance in their EPR suggest that pulses in physical forcing and subsequent primary production will be severely damped by trophodynamic processes before reaching larval fish.     

High-performance liquid chromatography and micellar electrokinetic chromatography of taxol and related taxanes from bark and needle extracts of Taxus species

High-performance liquid chromatography (HPLC) and micellar electrokinetic chromatography (MEKC) were applied for the separation of taxol, cephalomannine, and baccatin III in crude extracts from the needle and bark of Taxus species. The chromatogram of the bark extract was cleaner than that of the needle allowing a more reliable detection of taxol and cephalomannine in the bark extract. However, HPLC quantitation of taxol in the needle extract would be difficult due to coeluting taxinines. Nevertheless, this was not a problem in the MEKC experiment. In comparison to HPLC, MEKC offered baseline resolution of taxol from taxinines in the needle extract, less solvent waste, a smaller sample requirement, and the simultaneous detection of taxol, cephalomannine and baccatin III in a relatively simpler electrophoretic run.     

Gene-sized DNA molecules of the macronuclei in three species of hypotrichs: Size distributions and absence of nicks

Macronuclear DNAs from three related hypotrichous ciliated protozoans were compared by agarose gel electrophoresis. Each was shown to be composed of DNA duplexes that yielded a unique pattern of bands overlying a continuous distribution of DNA sizes ranging from 400 bp to 20,000 bp. By EM, the number average molecular sizes for doublestranded DNA were 2,200 bp for Oxytricha sp., 2,514 bp for Stylonychia pustulata and 1,836 bp for Euplotes aediculatus. Contrary to previous reports we present evidence that the macronuclear DNAs in each of these three organisms lack single-stranded interruptions.     

Identification of a ∼30S size non-ribosomal Saccharomyces cerevisiae RNA that is rapidly labeled on its 3′ end by ATP or UTP

Cell-free extracts prepared from S. cerevisiae cells were incubated in the presence of [-³²P]-labeled ATP, CTP, GTP or UTP. An RNA larger than ribosomal 25S RNA with an apparent size of approximately 30S was prominently labeled on its 3 end in the presence of ATP or UTP but not with CTP or GTP. This labeled RNA was not hybrid-selected by cloned yeast ribosomal DNA; in addition, this 30S RNA was not cleaved by RNase H in the presence of complementary deoxyribooligonucleotides to rRNA. These two lines of evidence show that this 30S RNA is not structurally related to ribosomal RNA gene repeat. The cell-free extracts prepared from yeast cells containing temperature-sensitive poly(A) polymerase adenylated this novel yeast RNA at restrictive temperature with efficiency similar to extracts prepared from wild-type yeast cells. These data show that the enzyme responsible for adenylation of this 30S RNA is distinct from mRNA poly(A) polymerase. While the human SRP RNA 3 adenylating enzyme in the HeLa cell extract adenylated human SRP or Alu RNAs, the yeast adenylating enzyme did not adenylate the human SRP or Alu RNAs in vitro; these data indicate species specificity for this adenylating enzyme.     

Genomic diversity within Taxus cuspidata var. nana revealed by random amplified polymorphic DNA markers

Taxus cuspidata var. nana is a cultivated variety of Taxus cuspidata and contains taxol, a valuable secondary metabolite of medical importance, both in their stems and leaves. In this paper, random amplified polymorphic DNA (RAPD) markers were used to assess the genomic diversity of individual plants within T. cuspidata population. Seventy-four randomly selected plants were analyzed by 29 selected primers among which 25 primers produced polymorphic banding patterns. The coefficient of similarity among the plants ranged from 0.30 to 1.00 with a mean of 0.605. Our results showed that a surprisingly high level of genomic diversity existed within T. cuspidata, and RAPD markers were effective in revealing the diversity. Cluster analysis divided the plants into two groups. This data, when taken together with earlier findings showing variation in taxol content within a natural population of T. cuspidata, suggests a tantalizing possibility for selecting genomically homogeneous T. cuspidata plant lines with elevated and stable taxol content. Published in Russian in Fiziologiya Rastenii, 2006, Vol. 53, No. 5, pp. 771–776. The text was submitted by the authors in English.     

Increased taxane accumulation in callus cultures of Taxus cuspidata and Taxus × media by some elicitors and precursors

In Taxus cuspidata callus, vanadyl sulfate (10 mg l^–1) induced a high (146 g g^–1 dry wt) production of 10-deacetylbaccatin III in comparison to 7 g g^–1 dry wt of the control. The content of paclitaxel in this species increased from 16 g g^–1 to 74 g g^–1 dry wt when 20 mg phenylalanine l^–1 was used. In T. media, p-aminobenzoic acid induced the highest content of 10-deacetylbaccatin III (481 g g^–1 dry wt) versus 181 g g^–1 in the control. Paclitaxel increased from 89 to 139 g g^–1 dry wt after adding chitosan (20 mg l^–1) to the cultures.     

Physiological ecology of Juniperus virginiana in oldfields

Juniperus virginiana plants grow faster than other associated tree species in abandoned fields. During the summer the needles of the species do not light saturate even at 1,750 E m^-2 s^-1, reach optimum photosynthesis at 20°C, and maintain maximum photosynthesis at-8 to-12 bar twig water potential. In the field, the plants experience pronounced daily changes in water potential. The magnitude of the changes becomes more pronounced later in the summer. Leaves of the mature plants have highest rate of photosynthesis, young trees intermediate, and seedlings lowest. In winter there is a slight shift in optimum temperature for photosynthesis and the plants photosynthesize at 0°C. The rates of photosynthesis are lower in winter than in summer. On sunny days with calm winds, mature individuals and seedlings maintain significantly higher temperatures than air temperature while intermediate plants do not. The latter exhibit a lower photosynthetic rate than both mature plants and seedlings. The trends of photosynthesis, in the 3 size classes, both in winter and summer, correspond to the chlorophyll content of their leaves. It is concluded that J. virginiana grows well in open field habitats because it is a sun-adapted, drought resistant species with a long growing season which includes winter. The species is excluded from mature forests because it is shade-intolerant.     

Expression of recombinant alpha and beta tubulins from the yew Taxus cuspidata and analysis of the microtubule assembly in the presence of taxol

Taxol was originally isolated from the yew Taxus brevifolia. Because taxol inhibits the depolymerization of microtubules, the presence of a self-resistance mechanism in Taxus spp. was hypothesized. The cloning of the cDNA for alpha and beta tubulins from Taxus cuspidata and those from the human embryonic kidney cell line HEK293T revealed that the ²⁶Asp, ³⁵⁹Arg, and ³⁶¹Leu residues in the human beta tubulin, which are important for taxol binding, were replaced with Glu, Trp, and Met in the beta tubulin of T. cuspidata, respectively. The microtubule assembly of the recombinant alpha and beta tubulins was monitored turbidimetrically, and the results clearly demonstrated that the microtubule from T. cuspidata is less sensitive to taxol than that from HEK293T cells. The Taxus microtubule composed of the wild-type alpha tubulin and the beta tubulin with the E26D mutation restored the sensitivity to taxol. We thus postulated that the mutation identified in the beta tubulin of T. cuspidata plays a role in the self-resistance of this species against taxol.     

rDNA targeted oligonucleotide primers for the identification of pathogenic yeasts in a polymerase chain reaction

Summary Species-specific oligonucleotide primers were designed for PCR identification of the basidiomycetous yeastsCryptococcus neoformans, Trichosporon cutaneum andRhodotorula mucilaginosa. The procedure uses standard PCR components including DNA from the test species and three primers: two universal external (upstream and downstream) limiting primers and a species-specific internal primer. Species identification requires the formation of a species-specific rDNA nucleotide segment that is significantly smaller (200 bp) than a non-target segment (600 bp). The procedure can be used to identify yeasts from single and mixed populations.This paper is dedicated to Professor Herman Jan Phaff in honor of his 50 years of active research which still continues.     

Response of egg temperature,heart rate and blood pressure in the chick embryo to hypothermal stress

Summary Chicken eggs incubated for 12–18 days were catheterized via the allantoic artery and temperature was monitored simultaneously using a probe positioned in the allantoic fluid adjacent to the embryo. Fluid temperature (referred to as egg temperature), arterial pressure and heart rate were measured following abrupt exposure to a lower environmental temperature (ca., 2628°C). Egg temperature and heart rate diminished exponentially: The rate of decline of egg temperature approximated Newton's law of cooling, the rate coefficient being 0.0220.025°C/min·°C throughout the incubation period from 12 to 18 days. The half time of temperature response of the egg was 2728 min. The response was much slower than that of fertile unincubated eggs (Kaplan et al. 1978), suggesting that the extraembryonic fluids act as a thermal buffer in embryonated eggs. The heart rate response in older embryos (1718 days) changed in the same manner as egg temperature, while in younger embryos (1216 days) the heart rate diminished more quickly than the change in egg temperature. During development the cardiac pacing of the embryo suggests that it becomes resistive to mild cold stress. The systolic pressure remained almost unchanged or even increased during one hour of exposure as the embryo developed, while the diastolic pressure decreased steadily after exposure irrespective of development. The 18-day-old embryos retained the systolic pressure unaltered during 3-hour exposure. In embryos 34 days prior to hatching the functional capacity of the heart apparently allows continued pumping even after prolonged exposure to low environmental temperature. Symbols and Abbreviations: See definitions at the end of the Materials and methods section     

Effects of taurine on the phosphorylation of specific proteins in subcellular fractions of the rat retina

The effects of 20 mM taurine on the phosphorylation of specific proteins in mitochondrial and rod outer segment subcellular fractions of the rat retina were measured. A band of protein with an apparent molecular wieght of 20K was consistently inhibited by taurine. Densitometry measurements performed on gel electrophoresis autoradiograms from the mitochondrial fraction demonstrated a 42.7±8.3% decrease due to taurine (20 mM) in the area corresponding to radioactivity from the 20K phosphoprotein. However, only a 21.2±9.0% decrease was observed due to taurine in the rod outer segment preparation. These data suggest that taurine is exerting its primary effect on the phosphorylation of the 20K molecular weight protein in the mitochondria of the retina. In addition, calmodulin and phorbol ester had no effect on the phosphorylation of the 20K molecular weight protein.     

New taxol assay method using tubulin-assembly stimulation

Summary A novel taxol determination method which involves the tubulin-assembly stimulation is described. The tubulin-assembly was monitored by turbidity change at 350nm. In a limited range of taxol concentration (0 to 24 M), taxol stimulated tubulin-assembly linearly. And this linear relation was observed from 20min to 30min after the reaction started. Bioactive derivatives of taxol, such as cephalomanin and 7-epi-10-deacetyltaxol also stimulated the tubulin-assembly. However, baccatin III, which was known as less active taxol derivative did not stimulate tubulin assembly. This result showed that the stimulation of tubulin assembly has a relationship with the antimiotic activity. This assay method have several advantages. 1) Time required for the measurement is relatively short. 2) Multiple samples can be measured simultaneously. 3) It can remove interference of less active taxane compounds more selectively than immuno-assay. Consequently, this method can be used to determine taxol concentration in biological samples. Especially, this method can be used for large scale selection of cell line and primary screening of new antimiotic compounds.     

15-Cis-carotenoids found in the reaction center of a green sulfur bacterium Chlorobium tepidum and in the Photosystem I reaction center of a cyanobacterium Synechococcus vulcanus

Carotenoids were extracted, at 4 °C in complete darkness and under nitrogen atmosphere, from the reaction center (RC) of a green-sulfur bacterium and the Photosystem (PS) I RC of a cyanobacterium; each extract was subjected to high-performance liquid chromatography (HPLC) using an apparatus equipped with a two-dimensional diode-array detector in order to spectroscopically identify cis–trans carotenoids while performing HPLC analysis. In the extract from the RC of Chlorobium tepidum, 15-cis and all-trans--carotenes as well as 13-cis-, 15-cis- and all- trans-chlorobactenes (in the order of elution) were identified, whereas in the extract from the PS I RC of Synechococcus vulcanus, 15-cis-, all-trans- and 9-cis--carotenes were found. Thus, the universal presence of 15- cis carotenoids in the 'iron sulfur-type' RCs has been shown in addition to the previous cases of the 'quinone-type' RCs.     

Immunoreactivity of the corpuscles of Stannius of the garpike,Lepisosteus osseus,to antisera against salmon and trout stanniocalcins

Stanniocalcin-immunoreactive cells were localized in the corpuscles of Stannius of a holostean fish, the garpike (Lepisosteus osseus), using antisera against salmon and trout stanniocalcins and the peroxidase-antiperoxidase and protein A-gold immunohistochemical methods. The stanniocalcin-immunoreactive cells were periodic acid-Schiff-positive, and antibody staining was abolished if the antiserum was preabsorbed with corpuscle homogenate. Immunocytochemistry revealed two reactive cell types in the glandular parenchyma, and immunoreactivity was confined to the secretory granules. Staining of the granules was also abolished when the antisera were blocked with crude corpuscle homogenate. When corpuscle extracts from garpike were subjected to sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blot analysis, a single dense band was evident with a molecular weight of 68 kDa under non-reducing conditions, whereas three bands were observed (29, 31, and 34 kDa) under reducing conditions. Staining of all bands disappeared following preabsorption of the antiserum with salmon stanniocalcin, trout stanniocalcin, or garpike corpuscle extract. The results are compared with stanniocalcins from another extant holostean, the bowfin (Amia calva), and from more modern bony fishes, the teleosts.