scholarly journals Pythium kandovanense sp. nov., a fungus-like eukaryotic micro-organism (Stramenopila, Pythiales) isolated from snow-covered ryegrass leaves

2015 ◽  
Vol 65 (Pt_8) ◽  
pp. 2500-2506 ◽  
Author(s):  
Ali Chenari Bouket ◽  
Mahdi Arzanlou ◽  
Motoaki Tojo ◽  
Asadollah Babai-Ahari

Pythium kandovanense sp. nov. (ex-type culture CCTU 1813T = OPU 1626T = CBS 139567T) is a novel oomycete species isolated from Lolium perenne with snow rot symptoms in a natural grassland in East-Azarbaijan province, Iran. Phylogenetic analyses based on sequence data from internal transcribed spacer (ITS)-rDNA, coxI and coxII mitochondrial genes clustered our isolates in Pythium group E as a unique, well supported clade. Pythium kandovanense sp. nov. is phylogenetically and morphologically distinct from the other closely related species in this clade, namely Pythium rostratifingens and Pythium rostratum. Pythium kandovanense sp. nov. can be distinguished from these two species by its cylindrical sporangia and lower temperatures for optimum and maximum growth rate. The development of zoospores released through a shorter discharge tube is an additional morphological feature which can be used to differentiate Pythium kandovanense sp. nov. from Pythium rostratifingens. Laboratory inoculation tests demonstrated the pathogenicity of Pythium kandovanense sp. nov. to L. perenne under wet cold (0–3 °C) conditions.

2011 ◽  
Vol 86 (2) ◽  
pp. 245-251 ◽  
Author(s):  
R.S. Dai ◽  
G.H. Liu ◽  
H.Q. Song ◽  
R.Q. Lin ◽  
Z.G. Yuan ◽  
...  

AbstractSequence variability in two mitochondrial DNA (mtDNA) regions, namely cytochromecoxidase subunit 1 (cox1) and NADH dehydrogenase subunit 4 (nad4), and internal transcribed spacer (ITS) of rDNA among and within three cestodes,Spirometra erinaceieuropaei,Taenia multicepsandTaenia hydatigena, from different geographical origins in China was examined. A portion of thecox1 (pcox1),nad4 genes (pnad4) and the ITS (ITS1+5.8S rDNA+ITS2) were amplified separately from individual cestodes by polymerase chain reaction (PCR). Representative amplicons were subjected to sequencing in order to estimate sequence variability. While the intra-specific sequence variations within each of the tapeworm species were 0–0.7% for pcox1, 0–1.7% for pnad4 and 0.1–3.6% for ITS, the inter-specific sequence differences were significantly higher, being 12.1–17.6%, 18.7–26.2% and 31–75.5% for pcox1, pnad4 and ITS, respectively. Phylogenetic analyses based on the pcox1 sequence data revealed thatT. multicepsandT. hydatigenawere more closely related to the other members of theTaeniagenus, andS. erinaceieuropaeiwas more closely related to the other members of theSpirometragenus. These findings demonstrated clearly the usefulness of mtDNA and rDNA sequences for population genetic studies of these cestodes of socio-economic importance.


Phytotaxa ◽  
2016 ◽  
Vol 280 (2) ◽  
pp. 116 ◽  
Author(s):  
HUILI LI ◽  
XUELAN MA ◽  
PETER E. MORTIMER ◽  
SAMANTHA C. KARUNARATHNA ◽  
JIANCHU XU ◽  
...  

Four specimens of Phallus were collected during surveys in a Pinus armandii forest in Baoshan, Yunnan Province, China. Macro- and micro-characteristics, together with Internal Transcribed Spacer (ITS) sequence data, showed that the four specimens belong to a new species, here named Phallus haitangensis. The ITS phylogenetic analyses, morphological descriptions, color photographs, and line drawings are provided, and compared with closely related species in the genus.


2019 ◽  
Vol 11 (10) ◽  
pp. 2824-2849 ◽  
Author(s):  
Paweł Mackiewicz ◽  
Adam Dawid Urantówka ◽  
Aleksandra Kroczak ◽  
Dorota Mackiewicz

Abstract Mitochondrial genes are placed on one molecule, which implies that they should carry consistent phylogenetic information. Following this advantage, we present a well-supported phylogeny based on mitochondrial genomes from almost 300 representatives of Passeriformes, the most numerous and differentiated Aves order. The analyses resolved the phylogenetic position of paraphyletic Basal and Transitional Oscines. Passerida occurred divided into two groups, one containing Paroidea and Sylvioidea, whereas the other, Passeroidea and Muscicapoidea. Analyses of mitogenomes showed four types of rearrangements including a duplicated control region (CR) with adjacent genes. Mapping the presence and absence of duplications onto the phylogenetic tree revealed that the duplication was the ancestral state for passerines and was maintained in early diverged lineages. Next, the duplication could be lost and occurred independently at least four times according to the most parsimonious scenario. In some lineages, two CR copies have been inherited from an ancient duplication and highly diverged, whereas in others, the second copy became similar to the first one due to concerted evolution. The second CR copies accumulated over twice as many substitutions as the first ones. However, the second CRs were not completely eliminated and were retained for a long time, which suggests that both regions can fulfill an important role in mitogenomes. Phylogenetic analyses based on CR sequences subjected to the complex evolution can produce tree topologies inconsistent with real evolutionary relationships between species. Passerines with two CRs showed a higher metabolic rate in relation to their body mass.


1993 ◽  
Vol 57 (2) ◽  
pp. 332-334 ◽  
Author(s):  
A. Blasco ◽  
E. Gómez

Two synthetic lines of rabbits were used in the experiment. Line V, selected on litter size, and line R, selected on growth rate. Ninety-six animals were randomly collected from 48 litters, taking a male and a female each time. Richards and Gompertz growth curves were fitted. Sexual dimorphism appeared in the line V but not in the R. Values for b and k were similar in all curves. Maximum growth rate took place in weeks 7 to 8. A break due to weaning could be observed in weeks 4 to 5. Although there is a remarkable similarity of the values of all the parameters using data from the first 20 weeks only, the higher standard errors on adult weight would make 30 weeks the preferable time to take data for live-weight growth curves.


1978 ◽  
Vol 14 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. L. Monteith

SUMMARYFigures for maximum crop growth rates, reviewed by Gifford (1974), suggest that the productivity of C3 and C4 species is almost indistinguishable. However, close inspection of these figures at source and correspondence with several authors revealed a number of errors. When all unreliable figures were discarded, the maximum growth rate for C3 stands fell in the range 34–39 g m−2 d−1 compared with 50–54 g m−2 d−1 for C4 stands. Maximum growth rates averaged over the whole growing season showed a similar difference: 13 g m−2 d−1 for C3 and 22 g m−2 d−1 for C4. These figures correspond to photosynthetic efficiencies of approximately 1·4 and 2·0%.


1992 ◽  
Vol 25 (6) ◽  
pp. 167-183 ◽  
Author(s):  
H. Siegrist ◽  
M. Tschui

The wastewater of the municipal treatment plants Zürich-Werdhölzli (350000 population equivalents), Zürich-Glatt (110000), and Wattwil (20000) have been characterized with regard to the activated sludge model Nr.1 of the IAWPRC task group. Zürich-Glatt and Wattwil are partly nitrifying treatment plants and Zürich-Werdhölzli is fully nitrifying. The mixing characteristics of the aeration tanks at Werdhölzli and Glatt were determined with sodium bromide as a tracer. The experimental data were used to calibrate hydrolysis, heterotrophic growth and nitrification. Problems arising by calibrating hydrolysis of the paniculate material and by measuring oxygen consumption of heterotrophic and nitrifying microorganisms are discussed. For hydrolysis the experimental data indicate first-order kinetics. For nitrification a maximum growth rate of 0.40±0.07 d−1, corresponding to an observed growth rate of 0.26±0.04 d−1 was calculated at 10°C. The half velocity constant found for 12 and 20°C was 2 mg NH4-N/l. The calibrated model was verified with experimental dam of me Zürich-Werdhölzli treatment plant during ammonia shock load.


1987 ◽  
Vol 44 (11) ◽  
pp. 1995-2001 ◽  
Author(s):  
Stephen H. Bowen

It is widely believed that fishes require more dietary protein than other vertebrates. Many aspects of fish physiology, nutrition, and trophic ecology have been interpreted within the context of this high protein requirement. Here, fishes are compared with terrestrial homeotherms in terms of (1) protein requirement for maintenance, (2) relative protein concentration in the diet required for maximum growth rate, (3) protein intake rate required for maximum growth rate, (4) efficiency of protein retention in growth, and (5) weight of growth achieved per weight of protein ingested. The two animal groups compared differ only in relative protein concentration in the diet required for maximum growth rate. This difference is explained in terms of homeotherms' greater requirement for energy and does not reflect absolute differences in protein requirement. The remaining measures of protein requirement suggest that fishes and terrestrial homeotherms are remarkably similar in their use of protein as a nutritional resource. Reinterpretation of the role of protein in fish physiology, nutrition, and trophic ecology is perhaps in order.


2012 ◽  
Vol 57 (2) ◽  
pp. 554-566 ◽  
Author(s):  
Kyle F. Edwards ◽  
Mridul K. Thomas ◽  
Christopher A. Klausmeier ◽  
Elena Litchman

1993 ◽  
Vol 248 ◽  
pp. 363-381 ◽  
Author(s):  
G. H. Wheless ◽  
G. T. Csanady

We used a compound matrix method to integrate the Orr–Sommerfeld equation in an investigation of short instability waves (λ < 6 cm) on the coupled shear flow at the air–sea interface under suddenly imposed wind (a gust model). The method is robust and fast, so that the effects of external variables on growth rate could easily be explored. As expected from past theoretical studies, the growth rate proved sensitive to air and water viscosity, and to the curvature of the air velocity profile very close to the interface. Surface tension had less influence, growth rate increasing somewhat with decreasing surface tension. Maximum growth rate and minimum wave speed nearly coincided for some combinations of fluid properties, but not for others.The most important new finding is that, contrary to some past order of magnitude estimates made on theoretical grounds, the eigenfunctions at these short wavelengths are confined to a distance of the order of the viscous wave boundary-layer thickness from the interface. Correspondingly, the perturbation vorticity is high, the streamwise surface velocity perturbation in typical cases being five times the orbital velocity of free waves on an undisturbed water surface. The instability waves should therefore be thought of as fundamentally different flow structures from free waves: given their high vorticity, they are akin to incipient turbulent eddies. They may also be expected to break at a much lower steepness than free waves.


Sign in / Sign up

Export Citation Format

Share Document