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761.
《Fungal Ecology》2015
Fungal endophytes are species rich and ubiquitous, yet, apart from the genus Epichloë, their ecology is largely unknown. Here we explore how herbivores affect the diversity of fungal endophytes in tundra grasslands. We assess both hyphal morphological and taxonomic diversity in grass individuals.By microscopic examination we identified endophytes to be present in all sampled grass individuals whereas identification to taxonomic units were only achieved in a subset of the individuals using laser micro dissection pressure catapulting and culturing for endophyte isolation. Hyphal morphological diversity was significantly higher in grasses exposed to grazing, along with 45 % more taxonomic units achieved.Our results suggest that grazing is an important mediator of fungal endophyte diversity in tundra grasslands. Furthermore, we suggest laser dissection of stained endophytes as a method for further exploring the ecological role of fungal endophytes. 相似文献
762.
K. Wolff 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,81(1):119-126
Summary The level of electrophoretic variability in three Plantago species, P. major, P. coronopus, and P. lanceolata, was analyzed in relation to their breeding systems and compared with their morphological variability. From each species several populations were analyzed. The outcrossing P. lanceolata had the highest level of electrophoretic variability and the lowest population differentiation. The inbreeding P. major showed the opposite: a low level of electrophoretic variability and a high population differentiation. P. coronopus, with an intermediate breeding system, had an intermediate level of variability and differentiation. In comparing the species, it appeared that P. coronopus and P. major showed good concordance in the distribution of both kinds of variability, each having only a slightly higher morphological than electrophoretic differentiation between populations. P. lanceolata showed a higher morphological than electrophoretic differentiation between populations. A comparison of populations, within species, revealed good concordance of electrophoretic and morphological variability only within P. coronopus, while some populations of the other two species had relatively lower morphological variability compared with electrophoretic variability.Grassland Species Research Group Publication No. 182 相似文献
763.
《Harmful algae》2019
Marine dinoflagellates of the genus Dinophysis are well known for producing diarrhetic shellfish poisoning (DSP) toxins and/or pectenotoxins which have a significant impact on public health as well as on marine aquaculture. Out of more than 80 Dinophysis species recorded so far, D. cf. acuminata is the most commonly observed in coastal areas worldwide. Due to their highly similar morphological features, however, an accurate discrimination of the various D. cf. acuminata species such as D. acuminata, D. ovum, and D. sacculus under light microscopy has proven to be a difficult task to accomplish. Hence, these species have thus far been referred to as the “Dinophysis acuminata complex”. Recent studies showed a discrimination between local strains of D. acuminata and D. ovum from Galician, northwestern Spain, using the mitochondrial cox1 gene as a genetic marker in addition to commonly used morphological features such as size and contour of the large hypothecal plates, shape of the small cells formed as part of their polymorphic life-cycle, development of the left sulcal list and ribs, and length of the right sulcal list. In the present study, attempts were made to discriminate between D. acuminata and D. ovum following single-cell isolation of 54 “D. acuminata complex” collected from Korean coastal waters, based on the abovementioned traits. Morphological data showed that all the traits analyzed overlapped between the two species. The mitochondrial cox1 (cytochrome c oxidase subunit I) gene sequences of every isolate were also determined, but a genetic distinction between D. acuminata and D. ovum could not be confirmed, suggesting that the cox1 gene is not a suitable genetic marker for discrimination between the two species. The results of this study suggest that the morphological variations observed within the “D. acuminata complex” may have been caused by several factors (e.g. different geographical locations, seasonal changes, and different environmental conditions), and that D. acuminata and D. ovum may be the same species. 相似文献
764.
《Saudi Journal of Biological Sciences》2020,27(2):643-652
This study utilized genetic and morphometric approaches to assess the molecular and morphometric differentiation among commercially important species of mud crab. Molecular investigations were derived from 542 bp mitochondrial DNA COI on 249 individuals within genus Scylla from nine states in Malaysia represents four marine regions; South China Sea, Sulu Sea, Straits of Singapore and Straits of Malacca. Four specimens were obtained from Indonesia to give a robust analysis in this study. For species delimitation, Automatic Barcode Gap Discovery (ABGD) method on a web interface was employed. Analysis on phylogenetics was implemented utilizing Neighbour joining (NJ) and Maximum Parsimony (MP) methods. The inter- and intraspecies genetic distances (Ds) was computed using Kimura 2-parameter distance and executed in MEGA version 5.05. All samples were genetically and morphologically identified and clustered into four distinct species. Among the species, S. olivacea was the most abundant (n = 111), on the other hand the occurrence of S. paramamosain in Malaysia was very low (n = 29). No single individual of S. serrata from Malaysia was recorded in this study. Both genetic distance and phylogenetic approaches exhibited a correlative monophyletic association among all specimens analysed. This present study is crucial as it reports the reassessment of all species within genus Scylla in Malaysia, eventually could be employed as a reference source for subsequent research mainly on mariculture and other conservation efforts for the species. 相似文献
765.
Maria V. Triantaphyllou Theodora Tsourou Olga Koukousioura Michael D. Dermitzakis 《Revue de Micropaléontologie》2005,48(4):279-302
A comparative study of recent epiphytal ostracod and benthic foraminiferal populations was conducted in August 2001, at two gulfs (Korthi and Kastro) located at the southeastern part of Andros Island (middle Aegean Sea, Greece). Thirty samples (representing living macro-benthic algae and seagrasses) from both gulfs were studied and a total of 34 ostracod species and 60 benthic foraminiferal species were identified. In the gulf of Korthi both benthic foraminiferal and epiphytal ostracod assemblages were characterized by high abundances of Amphistegina lessonii and Xestoleberis spp., respectively, therefore the performed Q-mode cluster analysis verified the presence of a Normal Environment Biofacies (NE). Declined Environment (DE) and Stressed (SE) Environment Biofacies were recognized in the gulf of Kastro, an area more affected by anthropogenic activities. Several deformed foraminiferal specimens have been documented in the assemblages from both gulfs, but malformed tests are significantly increased in SE Biofacies of Kastro gulf. This study suggests that great accumulations of A. lessonii (35-60%) associated with high frequencies of Xestoleberis communis and/or Xestoleberis decipiens and high species diversities can be used as bioindicators of coastal health. 相似文献
766.
A quantitative genetic model for growth,shape, reaction norms,and other infinite-dimensional characters 总被引:22,自引:0,他引:22
Infinite-dimensional characters are those in which the phenotype of an individual is described by a function, rather than by a finite set of measurements. Examples include growth trajectories, morphological shapes, and norms of reaction. Methods are presented here that allow individual phenotypes, population means, and patterns of variance and covariance to be quantified for infinite-dimensional characters. A quantitative-genetic model is developed, and the recursion equation for the evolution of the population mean phenotype of an infinite-dimensional character is derived. The infinite-dimensional method offers three advantages over conventional finite-dimensional methods when applied to this kind of trait: (1) it describes the trait at all points rather than at a finite number of landmarks, (2) it eliminates errors in predicting the evolutionary response to selection made by conventional methods because they neglect the effects of selection on some parts of the trait, and (3) it estimates parameters of interest more efficiently. 相似文献
767.
Fethi Ben Abdallah Rihab Lagha Amina Bakhrouf 《World journal of microbiology & biotechnology》2008,24(8):1507-1512
Salmonella bovismorbificans, rare serovar, isolated from patient in Tunisia were incubated during 13 years in soil. After its resuscitation, the cells
showed a biochemical profile completely inactive on Api 20E system. These cells recuperated their initial characters after
6 months of incubation in Tryptic Soy broth. The atomic force micrographs showed a reduction of the cells size and an evolution
to coccoid-shapes. After resuscitation S. bovismorbificans cells recuperated their original rod shape. These cells showed an altered envelope. The resuscitate cells were identified
by PCR following the amplification of the internal transcribed spacer (ITS) region of 16S–23S rRNA gene. 相似文献
768.
《Saudi Journal of Biological Sciences》2023,30(5):103633
The present investigation explores the variability of Bunium persicum populations belonging to different regions. Variability among 74 genotypes for thirty-seven traits (29 quantitative and 8 qualitative) were studied to ascertain the population structure of the Bunium persicum. Among the agro-morphological traits, wide range of variability was recorded in tuber shape, tuber colour, seed shape, seed colour, growth habit, leaf shape, leaf colour, umbel shape, umbel colour, plant height (22.90–96.52 cm), primary branches plant−1 (1–6), umbel diameter of primary umbel (6.17 – 13.67 cm), number of primary umbels plant−1 (1–12), umbels plant−1 (8–40), seed yield per plant (0.55–13.10 g), essential oil content (3.2–9.3 %) etc. Significant and positive association was observed between number of seeds primary-1 umbel (r = 0.91), plant height (r = 0.65), number of seeds primary-1 umbel (0.52), number of seeds primary-1 umbel (0.43), number of seeds secondary-1 umbel (0.38) with number of umblets secondary-1 umbel. Cluster analysis classified the genotypes with different geographical origin into two major clusters and sub-clusters. Cluster-I comprises of 50 genotypes and cluster - II of 24 genotypes while the genotype SRS-KZ-189 from Kargil population was separated as an individual sub-group. Principal component (PC1) and (PC2) harbors accounted 20.2% and 14% of total variation. Variability of Kalazeera genotypes would facilitate the plant breeders to implement and design various crop improvement programme in future. 相似文献
769.
The phylogenetic relationships of aquatic plant families Alismataceae and Limnocharitaceae were investigated by cladistic analysis of morphological and cytological characters. The use of morphological data allowed much wider taxon sampling than in recent molecular studies, and resulted in several new hypotheses. Limnocharitaceae was resolved as a paraphyletic group giving rise to the monophyletic Alismataceae, contradicting with the results from molecular studies. Most of the currently accepted genera were relatively well supported as monophyletic groups, with polyphyletic Caldesia and paraphyletic Limnophyton as notable exceptions. Phylogenetic relationships between different genera remained poorly supported, but it is suggested that the base chromosome number n = 11 is derived from the plesiomorphic n = 7. 相似文献
770.
Valery V. Ziuganov Galina Ju Golovatjuk Ksenia A. Savvaitova Victor F. Bugaev 《Environmental Biology of Fishes》1987,18(4):241-247
Synopsis Two sympatric morphs of threespine stickleback Gasterosteus aculeatus are found in Lake Azabachije (Kamchatka, USSR); resident low-plated leiurus and completely plated trachurus, migrating from the Bering sea into the Lake to spawn. The absence of the intermediate morph semiarmatus and significant differences in a number of characters are indicative of reproductive isolation. The results show that the
leiurus morph is common in the regions other than those with mild climate and small seasonal fluctuations of temperature. 相似文献