Scanning Electron Microscopy of Xiphinema,Longidorus, and Californidorus Stylet Morphology

Stylet ultrastructure of five Xiphinema, four Longidorus, and three Californidorus species was compared by scanning electron microscopy. Morphological differences were seen in the odontophores and odontostyle bases between the genera and some of the species. All Xiphinema studied had well-developed odontophore flanges; the Longidorus species lacked flanges, except for weakly developed ones in L. diadecturus; and none of the Californidorus had flanges. Three sinuses were present in the odontophores of all species. The sinuses varied in length depending upon species. In Xiphinema and Californidorus the odontostyle bases had distinct overlapping collars, but in Longidorus the collars were absent except for L. diadecturus. The odontostyle-odontophore junction from a lateral view appeared as a slanted transverse line in all the species, but in a dorsal view of Xiphinema and Californidorus it was V-shaped. Dorsal longitudinal seams of the odontostyle and odontophore were observed in all the species. The dorsally located odontostyle aperture was ca. 1 μm from the anterior end in all species, except in one Longidorus sp. it was ca. 4 μm from the end.     

Host Status of Crotalaria juncea,Sesamum indicum,Dolichos lablab,and Elymus glaucus to Meloidogyne javanica

Reproduction of Meloidogyne javanica on Crotalaria juncea PI 207657 and cv. Tropic Sun, Sesamum indicum, Dolichos lablab, and Elymus glaucus was assessed using a root-gall index, a reproductive index obtained by dividing the final population of juveniles (J2) in soil by the initial J2 population (Pf/Pi), and the number of J2 per gram of root recovered from roots by mist chamber extraction. Lycopersicon esculentum (cv. UC 204 C) was included as a susceptible host. The root-gall index and soil reproductive index were poor indicators of the host status of our test plants as compared with mist chamber extraction of J2 from roots. Lycopersicon esculentum had a mean root-gall index of 7.8. Some plants of S. indicum and E. glaucus had a few galls and other plants had none, with mean root-gall indices of 1.6 and 0.8, respectively. No galls were observed in C. juncea and D. lablab. Lycopersicon esculentum had the highest mean soil Pf/Pi value (mean = 1.93), while in C. juncea and some replicates of S. indicum no soil J2 were found. Even though some replicates had no galls, all replicates supported nematode reproduction. The mean numbers of J2 per gram root after 5 days of mist extraction were 447.7, 223.3, 165.5, 96.9, 42.3, and 41.9 for D. lablab, L. esculentum, E. glaucus, S. indicum, and C. juncea PI 207657 and cv. Tropic Sun, respectively. Accurate assessment of nematode resistance was influenced by sampling time and the nematode extraction technique used. Individual plants of both C. juncea and S. indicum supported nematode reproduction to some extent; however, both C. juncea and S. indicum have potential as cover crops to reduce M. javanica numbers.     

Pleistocene molluscan paleoecology and community structure of the Puerto Libertad region,Sonora, Mexico

An intertidal Pleistocene sandflat community is analyzed in terms of community structure, survivorship, inferred biomass distributions, predation patterns, and trophic structure. The distributions of the first-level consumers was controlled by substrate grain size. The distributions of the predators mirrored the concentrations of their prey. Because of differing burrowing abilities, the Libertad infauna produced a community stratification. This property concentrated large segments of biomass at different levels within the substrate. This mechanism buffered biospace-related competition. When similar interspecific depth habitation zones overlapped, one or the other taxon was density limited. Survivorship curves constructed from size-frequency data and the function D = S 1n (T+1) demonstrated that Lucina approximata experienced constant mortality; Chione califonniensis had a well-developed bimodality of age distributions and Tagelus californianus had increasing population mortality. These contrasting mortality patterns were related to depth of habitation and substrate stability. The internal volumes displaced by a growth series of selected taxa were used to estimate biomass distributions. In terms of biomass, the dominant community members had largest volumes in juveniles — a characteristic of a stable population. Other accessory taxa had large volumes in adults — a property of stationary populations. Theodoxus lutteofasciatus had constant mortality, Cerithium stercusmuscarum, Nassarius tiarula and Natica chemnitzii had curves similar to Chione. Predation patterns demonstrated that two trophic subwebs existed among the predators. Muricanthus nigritus, Hexaplex erythrostomus and Melongea patula preyed on Ostrea palmula, Megapitaria squalida and Cerithium. Natica consumed the juveniles of Chione, Lucina, Nassarius and Theodoxus. The annelid predators Conus regularis, Acteocina inculta and Bulla gouldiana composed a third subweb, not attacked by any molluscan carnivore. The highest predation rate occurred in Nassarius, the lowest among the deep infauna.Differing food preferences by predators served as a stabilizing mechanism maintaining community homeostasis by providing alternative food reserves. It was shown that bore-hole loci changed through ontogeny in selected taxa. Likewise, borehole patterns differed slightly on right and left valves of the same prey species. In general predation rates declined rapidly with advancing age. Highly localized borehole sites were found in Theodoxus, Natica and Nassarius — the prey of Natica. Cerithum, the prey of Muricanthus, had less localized borehole loci. This suggests the latter's predator was less “sensitive” to prey- “induced” responses for selective manipulation. The Libertad community declined when the substrate closed to recruitment by the accumulation of the shells from previous generations.     

海南霸王岭山地原始林与伐后林中木质藤本对支持木的选择

通过对海南霸王岭热带山地原始林与伐后林中树木及其攀附木质藤本的调查,研究原始林与伐后林中木质藤本对支持木的选择性。结果表明:1)6科优势树木中附藤率最高的是野牡丹科(Melastomataceae),附藤率最低的科,原始林中是山矾科(Symplocaceae),伐后林中是茜草科(Rubiaceae)。2)原始林中,谷木(Memecylon ligustrifolium)与线枝蒲桃(Syzygiumaraiocladum)的附藤比率和每木藤本数均高于样地平均水平;三角瓣花(Prismatomeris tetrandra)和龟背灰木(Symplocosandenophylla)的附藤比率均低于样地平均水平,而每木藤本数与样地平均水平之间没有显著差异。伐后林中,谷木的附藤比率和每木藤本数高于样地平均水平;九节(Psychotria rubra)的附藤比率和每木藤本数低于样地平均水平。3)杜仲藤(Parabariummicranthum)的主要支持木是谷木,夜花藤(Hypserpa nitida)的主要支持木是线枝蒲桃。研究表明,木质藤本对支持木在科和种水平上都具有选择性,因此木质藤本会对树木造成不对称影响,进而影响森林的结构和动态。     

Microbial Ecology of Activated Sludge: II. Bacteriophages, Bdellovibrio, Coliforms, and Other Organisms

A comparative estimation of the coliform population of raw sewage, activated sludge, and the effluent derived therefrom revealed that raw sewage had a preponderance of Escherichia coli (75%), as compared with 25 and 30%, respectively, in sludge and effluent. Nitrogen-free mannitol-sucrose enrichments of activated sludge resulted in the isolation of Azotobacter agilis, Aerobacter aerogenes, Corynebacterium laevaniformans, and an Achromabacter species. Sludge had a large population of C. laevaniformans and A. aerogenes but not of Azotobacter. The bacterial parasites, Bdellovibrio and bacteriophages, were not active during activated-sludge treatment. A 10-fold reduction in phage content occurred after 2 hr of aeration, but the Bdellovibrio population was unaffected.     

Isolation, structure, and characterization of the putative soluble amyloses from potato, wheat, and rice starches

Amylose, a putative linear α-(1→4)-glucan and a component of most starches, was isolated from potato, rice, and wheat starches by forming the 1-butanol complex in a solution of the starches. It previously had been found that these amyloses were incompletely hydrolyzed by β-amylase, indicating that it was partially branched. Solubilization of the butanol complex in water and steam distillation of the 1-butanol, followed by cooling to 4 °C gave precipitation of the double helical, linear, retrograded amylose over a 15 h period, leaving the soluble amylose in solution. The soluble amyloses were precipitated with two volumes of ethanol, and the precipitate was solubilized and reprecipitated to remove traces of linear amylose. The precipitated, soluble amyloses, were partially branched and had properties intermediate between linear amylose and amylopectin. The water solubility of the potato amylose was 10.52 mg/mL, with a number-average degree of polymerization (DP_n) of 8440 and 2.1% branch linkages that had a DP_n of 48; the water solubility of the rice amylose was 8.83 mg/mL, with a DP_n of 2911 and 1.4% branch linkages that had a DP_n of 72; and the water solubility of wheat amylose was 6.33 mg/mL, with a DP_n of 1160 and 1.6% branch linkages that had a DP_n of 64. The three soluble amyloses have structures and properties intermediate between the nearly water insoluble (?1 mg/mL), linear amylose, and the highly water-soluble, 4-5% branched, amylopectin.     

A Collagenolytic Fungus,Cunninghamella elegans,for Biological Control of Plant-parasitic Nematodes

The root-galling index of tomatoes inoculated with Meloidogyne javanica was decreased 70% when collagen was used as a soil amendment (0.1% w/w) and 90% when the amendment was supplemented with the collagenolytic fungus Cunninghamella elegans. The root-galling index was reduced 80% when the fungus was homogenized in collagen culture medium and added to soil without collagen supplement. Culture filtrates of the fungus C. elegans, grown on collagen as a single source of carbon and nitrogen, immobilized M. javanica second-stage juveniles and inhibited egg hatch. Root galling was reduced when tomato plants were inoculated with filtrate-treated juveniles. Culture filtrates reduced the motility of Rotylenchulus reniformis and Xiphinema index, but they had less effect on Anguina tritici and almost no effect on Ditylenchus dipsaci. Cunninghamella elegans had collagenolytic, elastolytic, keratinolytic, and nonspecific proteolytic activities when grown on collagen media, but only chitinolytic activity when grown on chitin media.     

Ingestion,Retention, and Transmission of two Strains of Raspberry Ring-spot Virus by Longidorus macrosoma

The transmission of two strains of raspberry ringspot virus (RRV) by small numbers of nematodes was compared. A strain of RRV from Scotland (RRV-S), originally found in the field associated with Longidorus elongatus, was transmitted frequently by L. elongatus but only once by L. macrosoma. A strain from England (RRV-E) associated with L. macrosoma in the field was transmitted infrequently by each species of nematode. The reasons why L. macrosoma infected only a small proportion of bait plants with virus were investigated, and it was found that most of the nematodes tested had fed on the source plants and many had ingested virus. Most nematodes exposed to RRV-E or RRV-S had fed on the roots of the bait plants and, when thin sections were examined by electron microscope, had retained particles (thought to be those of the virus) in the region of the anterior odontostyle, Thus, most nematodes seem to have had ample opportunity to transmit virus, and the low frequency of transmission may have been due to a failure of the virus particles to be released from the site of retention or to a lack of infectivity of the virus when L. macrosoma was the vector and Petunia hybrida was the host.     

The Aspergillus fumigatus sitA Phosphatase Homologue Is Important for Adhesion,Cell Wall Integrity,Biofilm Formation,and Virulence

Aspergillus fumigatus is an opportunistic pathogenic fungus able to infect immunocompromised patients, eventually causing disseminated infections that are difficult to control and lead to high mortality rates. It is important to understand how the signaling pathways that regulate these factors involved in virulence are orchestrated. Protein phosphatases are central to numerous signal transduction pathways. Here, we characterize the A. fumigatus protein phosphatase 2A SitA, the Saccharomyces cerevisiae Sit4p homologue. The sitA gene is not an essential gene, and we were able to construct an A. fumigatus null mutant. The ΔsitA strain had decreased MpkA phosphorylation levels, was more sensitive to cell wall-damaging agents, had increased β-(1,3)-glucan and chitin, was impaired in biofilm formation, and had decreased protein kinase C activity. The ΔsitA strain is more sensitive to several metals and ions, such as MnCl₂, CaCl₂, and LiCl, but it is more resistant to ZnSO₄. The ΔsitA strain was avirulent in a murine model of invasive pulmonary aspergillosis and induces an augmented tumor necrosis factor alpha (TNF-α) response in mouse macrophages. These results stress the importance of A. fumigatus SitA as a possible modulator of PkcA/MpkA activity and its involvement in the cell wall integrity pathway.     

Kinetics and efficiency of excitation energy transfer from chlorophylls,their heavy metal-substituted derivatives,and pheophytins to singlet oxygen

Time-resolved measurements of the singlet oxygen infrared (1269 nm) luminescence were used to follow the kinetics and efficiency of excitation energy transfer (EET) between chlorophyll (Chl) derivatives and oxygen in acetone. The studied pigments were Mg-Chl a and b and their heavy metal (Cu²⁺ and Zn²⁺)-substituted analogues, as well as pheophytin (Pheo) a and b. The efficiency of EET from chlorophyll to oxygen was highly dependent on the central ion in the pigment. Cu-Chl a and Cu-Chl b had the lowest efficiencies of singlet oxygen production, while Pheo a had a higher one, and Zn-Chl a had a similar one compared to Mg-Chl a. Also the side chain (position C-7, i.e. Chl a vs. Chl b) influenced the efficiency of singlet oxygen formation. In the case of square-planar complexes like Cu-Chl and Pheo, EET was more efficient in the Chl a derivatives than in those of Chl b; the opposite effect was observed in the case of the five- or six-coordinated Mg-Chl and Zn-Chl. As for the lifetime of the Chl triplet state, the most striking difference to Mg-Chl again was found in the case of Cu-Chls, which had much shorter lifetimes. Furthermore, the central ion in Chl affected the physical quenching of singlet oxygen: its efficiency was decreasing from Mg-Chl through Zn-Chl over Cu-Chl to Pheo. The results are discussed in the context of the oxidative stress accompanying heavy metal-induced stress in plants.     

Species delimitation in the Ponto-Caucasian Viola sieheana complex, based on evidence from allozymes, morphology, ploidy levels, and crossing experiments

Information from allozymes, ploidy levels, morphology, cross-compatibility and biogeography suggests that the easternmost occurrences of the Ponto-Caucasian Viola sieheana should be considered to belong to a separate species, V. caspia. Morphological characters delimitating V. sieheana and V. caspia are presented and discussed. The main distribution of V. sieheana s. str. is in the eastern Balkans, Turkey, Cyprus, and The Lebanon, and of V. caspia in the Caspio-Caucasian region westwards to Crimea and north-eastern Turkey. Their distributions in the intermediate areas remain unknown. Plants of V. sieheana s. str. from Cyprus, Greece, and Turkey were all blue-flowered and had the chromosome number 2n?=?12x?=?60. Its presence in the Peloponnese (Parnon, Ta?getos, Menalon) and in the Pindhos mountains, Greece, was confirmed. Reports of plants with 2n?=?8x?=?40 from these stations seem to refer to the sterile hybrid V. reichenbachiana?×?sieheana which is locally abundant. V. caspia from Azerbaijan had 2n?=?8x?=?40 and had either whitish or blue flowers. In spite of sympatry and almost complete cross-compatibility, the two corolla colour morphs showed strong allozymic differentiation in four out of seven isozyme systems, suggesting reproductive isolation and incipient speciation. Within section Viola, V. caspia and V. sieheana seem no more closely related to each other than to either of the other investigated European species. The possibility that V. sieheana is an ancient allopolyploid involving the Greek narrow endemic V. dirphya (2n?=?40) is discussed.     

Functional analyses of two syntaxin-like SNARE genes,GzSYN1 and GzSYN2, in the ascomycete Gibberella zeae

We identified two syntaxin-like SNARE genes, named GzSYN1 and GzSYN2, from the plant pathogenic ascomycete Gibberella zeae, and characterized the functions and cellular localization of these genes. The GzSYN1 deletion mutant (Δgzsyn1) had 71% reduced hyphal growth compared to the wild-type strain, but produced perithecia with normal ascospores. Δgzsyn2 had the same hyphal growth rate as the wild-type, but completely lost both self and female fertility. When Δgzsyn2 was spermatized for Δmat1-1 or Δmat1-2 strains, it retained its male fertility, but the ascus shape was abnormal and ascospore delimitation was delayed. The Δgzsyn1 and Δgzsyn2 virulence on barley was reduced by 67% and 75%, respectively, compared to the wild-type. The GFP::GzSYN1 fusion protein was localized in vesicles, vacuoles, plasma membranes, and septa, whereas GFP::GzSYN2 was found only in plasma membranes and septa. These results suggest that syntaxins have key roles in fungal development and virulence in G. zeae.     

Characterization of a New Burrowing Nematode Population,Radopholus citrophilus,from Hawaii

Karyotype, host preference, isozyzme patterns, morphometrics, and mating behavior of two burrowing nematode populations from Hawaii, one infecting Anthurium sp. and the second infecting Musa sp., were compared with Radopholus similis and R. citrophilus populations from Florida. The population from Anthurium sp. had five chromosomes (n = 5), and that from Musa sp. had four (n = 4). Neither of the Hawaiian nematode populations persisted in roots of Citrus limon or C. aurantium. Anthurium clarinerivum and A. hookeri were hosts of the burrowing nematode population from anthurium in Hawaii and of R. citrophilus from Florida, whereas the two anthurium species were poor hosts of the population from Musa sp. in Hawaii and R. similis from Florida. The isozyme pattern of the population isolated from anthurium was identical to that of R. citrophigus, whereas the pattern of the population from banana in Hawaii was identical to that of R. similis. Mating behavior between the burrowing nematode population isolated from Anthurium sp. and a Florida population of R. citrophilus supports their close taxonomic relationship. Mating was observed between the population from Anthurium sp. and the Florida population of R. citrophilus but not between the Hawaiian burrowing nematode population isolated from Musa sp. and a Florida population of R. citrophilus. These findings indicate that a previously unidentified population of R. citrophilus which does not parasitize citrus occurs in Hawaii.     

Isolation and properties of cytochrome c-553, cytochrome c-550, and cytochrome c-549, 554 from Nitrobacter agilis

Three c-type cytochromes isolated from Nitrobacter agilis were purified to apparent homogeneity: cytochrome c-553, cytochrome c-550 and cytochrome c-549, 554. Their amino acid composition and other properties were studied. Cytochrome c-553 was isolated as a partially reduced form and could not be oxidized by ferricyanide. The completely reduced form of the cytochrome had absorption maxima at 419, 524 and 553 nm. It had a molecular weight of 25 000 and dissociated into two polypeptides of equal size of 11 500 during SDS gel electrophoresis. The isoelectric point of cytochrome c-553 was pH 6.8. The ferricytochrome c-550 exhibited an absorption peak at 410 nm and the ferrocytochrome c showed peaks at 416, 521 and 550 nm. The molecular weight of the cytochrome estimated by gel filtration and by SDS gel electrophoresis was 12 500. It had an E_m(7) value of 0.27 V and isoelectric point pH 8.51. The N-terminal sequence of cytochrome c-550 showed a clear homology with the corresponding portions of the sequences of other c-type cytochromes. Cytochrome c-549, 554 possessed atypical absorption spectra with absorption peaks at 402 nm as oxidized form and at 419, 523, 549 and 554 nm when reduced with Na₂S₂O₄. Its molecular weight estimated by gel filtration and SDS polyacrylamide gel electrophoresis was 90 000 and 46 000, respectively. The cytochrome had an isoelectric point of pH 5.6. Cytochrome c-549, 554 was highly autoxidizable.     

Etiology-, Sex-, and Tumor Size-Based Differences in Adrenocorticotropin-Dependent Cushing Syndrome

ObjectiveTo examine demographic, clinical, and biochemical differences in patients with adrenocorticotropin (ACTH)-dependent Cushing syndrome (CS) based on etiology, sex, and tumor size.MethodsThis was a single-center study of 211 patients with ACTH-dependent CS followed for 35 years. Patients were stratified into 3 groups based on etiology: Cushing disease (CD)/transsphenoidal surgery, Cushing disease/total bilateral adrenalectomy (CD/TBA), and ectopic ACTH secretion (EAS). Patients were also stratified based on sex and tumor size (nonvisualized, microadenoma, and macroadenoma).ResultsCD was the commonest cause of ACTH-dependent CS (190; 90%). Most patients presented in the third decade (median age, 29 years). Clinical features, cortisol, and ACTH were significantly greater in the EAS group. The CD/TBA group had more nonvisualized tumors (22% vs 8%; P = .000) and smaller tumor size (4 vs 6 mm; P = .001) compared with the CD/transsphenoidal surgery group. There was female predominance in CD (2.06:1) and male predominance in EAS (2:1). Men had shorter duration of symptoms (2 years; P = .014), were younger (23 years; P = .001), had lower body mass index (25.1 kg/m²; P = .000), and had more severe disease (low bone mineral density, hypokalemia). Macroadenomas were frequent (46; 24.2%), and ACTH correlated with tumor size in CD (r = 0.226; P = .005).ConclusionOur cohort presented at an earlier age than the Western population with a distinct, but slightly lower, female predilection. Patients with CD undergoing TBA had frequent negative imaging. Men had a clinical profile suggesting aggressive disease. Microadenoma and macroadenoma were difficult to distinguish on a clinicobiochemical basis.     

Aspergillus nidulans UDP-glucose-4-epimerase UgeA has multiple roles in wall architecture,hyphal morphogenesis,and asexual development

Aspergillus nidulans UDP-glucose-4-epimerase UgeA interconverts UDP-glucose and UDP-galactose and participates in galactose metabolism. The sugar moiety of UDP-galactose is predominantly found as galactopyranose (Galp, the six-membered ring form), which is the substrate for UDP-galactopyranose mutase (encoded by ugmA) to generate UDP-galactofuranose (Galf, the five-membered ring form) that is found in fungal walls. In A. fumigatus, Galf residues appear to be important for virulence. The A. nidulans ugeAΔ strain is viable, and has defects including wide, slow growing, highly branched hyphae and reduced conidiation that resemble the ugmAΔ strain. As for the ugmAΔ strain, ugeAΔ colonies had substantially reduced sporulation but normal spore viability. Conidia of the ugeAΔ strain could not form colonies on galactose as a sole carbon source, however they produced short, multinucleate germlings suggesting they ceased to grow from starvation. UgeA purified from an expression plasmid had a relative molecular weight of 40.6 kDa, and showed in vitro UDP-glucose-4-epimerase activity. Transmission electron microscope cross-sections of wildtype, ugeAΔ, and ugmAΔ hyphae showed they had similar cytoplasmic contents but the walls of each strain were different in appearance and thickness. Both deletion strains showed increased substrate adhesion. Localization of UgeA-GFP and UgmA-GFP was cytoplasmic, and was similar on glucose and galactose. Neither gene product had a longitudinal polarized distribution. Localization of a UgmA-mRFP in a strain that resembled the ugmAΔ strain was cytoplasmic and lacked a longitudinal polarized distribution. The roles of UgeA in A. nidulans growth and morphogenesis are consistent with the importance of Galf, and are related but not identical to the roles of UgmA.     

Stomatal Behavior and Water Status of Maize, Sorghum, and Tobacco under Field Conditions: I. At High Soil Water Potential

Diurnal changes in the vertical profiles of irradiance incident upon the adaxial leaf surface (I), stomatal resistance (r_s), leaf water potential (ψ), osmotic potential (π), and turgor potential (P) were followed concurrently in crops of maize (Zea mays L. var. Pa 602A), sorghum (Sorghum bicolor [L.] Moench var. RS610), and tobacco (Nicotiana tabacum L. var. Havanna Seed 211) on several days in 1968 to 1970 when soil water potentials were high. In all three crops the r_s, measured with a ventilated diffusion porometer, the ψ, measured with the pressure chamber, the π, measured with a vapor pressure osmometer, and the calculated P, decreased from sunrise to reach minimum values near midday and then increased again in the afternoon. The diurnal range of all the variables was greater for leaves in the upper canopy than for those in the lower canopy. P was observed to decrease with decreasing ψ, but never became zero. Sorghum had a higher P at a ψ of, say −10 bars, than did maize, and maize had a higher P than tobacco at the same ψ. Moreover, at the same ψ the upper leaves in all canopies had a higher P than the lower leaves. When compared at high irradiances, r_s did not increase as ψ declined to −13, −15, and −10 bars or as P declined to 0.3, 3.5, and 1.2 bars in maize, sorghum, and tobacco, respectively. The relation between r_s and I in the upper, nonsenescent leaves of all three crops fits a hyperbolic curve, but the response varied with species and leaf senescence. The adaxial and abaxial epidermises had the same response of r_s to I in maize and sorghum, whereas in tobacco the adaxial epidermis had a higher r_s than the abaxial epidermis at all values of I. At equal values of I, tobacco had the lowest leaf resistance (r_l) and maize had the highest r_l. Senescent maize leaves had nonfunctional stomata, whereas the lowermost sorghum leaves had higher stomatal resistances on average than the other leaves.     

Variation of photosynthetic performance, nutrient uptake, and elemental composition of different generations and different thallus parts of Saccharina japonica

In order to illustrate the physiological variation of different generations and different thallus parts of Saccharina japonica, physiological parameters such as maximum and effective PSII photochemical efficiency, nutrient uptake, and elemental composition were determined in the laboratory. Photosynthetic analysis in different generations indicated that, although gametophytes had higher pigment contents than the sporophyte, they had lower values of F _v/F _m and ΔF/F′_m. The highest Chl a/Chl c ratio was found in sporophyte generation (3.98?±?0.01) and in the basal part of fresh thallus (2.66?±?0.02). The sporophyte had significantly higher values of nitrate uptake but lower values of phosphorus uptake than the gametophytes. The contents of nitrogen and carbon as well as C/N in gametophytes were significantly higher than those in sporophytes. In addition, the basal part of the S. japonica thallus had the highest C content (22.31?±?1.50 %) but the lowest N content (2.02?±?0.16 %), as well as the highest value of C/N (11.02?±?0.34).     

The Glc7p-interacting protein Bud14p attenuates polarized growth,pheromone response,and filamentous growth in Saccharomyces cerevisiae

A genetic selection in Saccharomyces cerevisiae for mutants that stimulate the mating pathway uncovered a mutant that had a hyperactive pheromone response pathway and also had hyperpolarized growth. Cloning and segregation analysis demonstrated that BUD14 was the affected gene. Disruption of BUD14 in wild-type cells caused mild stimulation of pheromone response pathway reporters, an increase in sensitivity to mating factor, and a hyperelongated shmoo morphology. The bud14 mutant also had hyperfilamentous growth. Consistent with a role in the control of cell polarity, a Bud14p-green fluorescent protein fusion was localized to sites of polarized growth in the cell. Bud14p shared morphogenetic functions with the Ste20p and Bni1p proteins as well as with the type 1 phosphatase Glc7p. The genetic interactions between BUD14 and GLC7 suggested a role for Glc7p in filamentous growth, and Glc7p was found to have a positive function in filamentous growth in yeast.