Topic
Linckia
About: Linckia is a research topic. Over the lifetime, 21 publications have been published within this topic receiving 408 citations.
Papers
TL;DR: Comparisons of phylogeographical patterns from mitochondrial COI sequences among two co‐distributed seastars that differ in their adult habitat and dispersal ability suggest that habitat differences may affect the manner in which species responded to Pleistocene sea‐level fluctuations, shaping contemporary patterns of genetic structure and diversity.
Abstract: Repeated exposure and flooding of the Sunda and Sahul shelves during Pleistocene sea-level fluctuations is thought to have contributed to the isolation and diversification of sea-basin populations within the Coral Triangle. This hypothesis has been tested in numerous phylogeographical studies, recovering an assortment of genetic patterns that the authors have generally attributed to differences in larval dispersal capability or adult habitat specificity. This study compares phylogeographical patterns from mitochondrial COI sequences among two co-distributed seastars that differ in their adult habitat and dispersal ability, and two seastar ectosymbionts that differ in their degree of host specificity. Of these, only the seastar Linckia laevigata displayed a classical pattern of Indian-Pacific divergence, but with only moderate genetic structure (ΦCT = 0.067). In contrast, the seastar Protoreaster nodosus exhibited strong structure (ΦCT = 0.23) between Teluk Cenderawasih and the remainder of Indonesia, a pattern of regional structure that was echoed in L. laevigata (ΦCT = 0.03) as well as its obligate gastropod parasite Thyca crystallina (ΦCT =0 .04). The generalist commensal shrimp, Periclimenes soror showed little genetic structuring across the Coral Triangle. Despite species-specific phylogeographical patterns, all four species showed departures from neutrality that are consistent with massive range expansions onto the continental shelves as the sea levels rose, and that date within the Pleistocene epoch. Our results suggest that habitat differences may affect the manner in which species responded to Pleistocene sea-level fluctuations, shaping contemporary patterns of genetic structure and diversity.
124 citations
TL;DR: Comparisons of data for both Alpheus and Linckia with data from other population genetic studies in the IWP suggest that nuclear markers may in some instances reveal historical patterns of genetic population structure whereas mtDNA variation better reflects present day patterns of gene flow.
Abstract: Simultaneous studies of both nuclear and mitochondrial markers were undertaken in two widespread Indo-West Pacific (IWP) marine invertebrates to compare and contrast the ability of these markers to resolve genetic structure. In particular, we were interested in the resolution of a genetic break between the Indian and Pacific Oceans due to historical isolation. Sequence variation from the nuclear gene encoding myosin heavy chain (MyHC) and the mitochondrial gene cytochrome oxidase I (COI) were examined for the snapping shrimp Alpheus lottini from wide-ranging populations throughout the Indian and Pacific Oceans. A previously identified genetic break between oceans based on COI sequences appears to have been an artifact caused by the inadvertent inclusion of pseudogene sequences; our new COI data provide evidence only of a break between IWP and East Pacific populations. Distribution of a single nucleotide polymorphism in MyHC, on the other hand, shows evidence of a cline between Indian and Pacific Oceans. New allozyme and mtDNA sequence data were also obtained for the starfish Linckia laevigata. Allozyme data show a clear genetic break between Indian Ocean populations and Pacific (including western Australian) populations, whereas the distribution of mtDNA haplotypes shows a region of overlap in the central IWP. Comparisons of our data for both Alpheus and Linckia with data from other population genetic studies in the IWP suggest that nuclear markers (allozymes, sequence data and morphological characters) may in some instances reveal historical patterns of genetic population structure whereas mtDNA variation better reflects present day patterns of gene flow.
89 citations
TL;DR: The observed patterns of within- and between-subfamily polymorphisms indicate that positive diversifying, balancing, and purifying selections are the principal driving forces of the kai gene family's evolution.
Abstract: Cyanobacteria are the only prokaryotes known thus far possessing regulation of physiological functions with approximate daily periodicity, or circadian rhythms, that are controlled by a cluster of three genes, kaiA, kaiB, and kaiC. Here we demonstrate considerably higher genetic polymorphism and extremely rapid evolution of the kaiABC gene family in a filamentous cyanobacterium, Nostoc linckia, permanently exposed to the acute natural environmental stress in the two microsite evolutionary models known as “Evolution Canyons,” I (Mount Carmel) and II (Upper Galilee) in Israel. The family consists of five distinct subfamilies (kaiI–kaiV) comprising at least 20 functional genes and pseudogenes. The obtained data suggest that the duplications of kai genes have adaptive significance, and some of them are evolutionarily quite recent (≈80,000 years ago). The observed patterns of within- and between-subfamily polymorphisms indicate that positive diversifying, balancing, and purifying selections are the principal driving forces of the kai gene family's evolution.
48 citations
TL;DR: A microalga, Chlorella vulgaris, and two diazotrophic cyanobacteria, Nostoc linckia and N. muscorum, all isolated from a rice soil, were compared for their response in terms of growth and metabolic activities to the application of carbofuran, indicating interference of the insecticide with membrane properties.
Abstract: A microalga, Chlorella vulgaris, and two diazotrophic cyanobacteria, Nostoc linckia and N. muscorum, all isolated from a rice soil, were compared for their response in terms of growth and metabolic activities to the application of carbofuran. The toxicity criteria included cell constituents (chlorophyll a, total protein, carbohydrate), 14CO2 uptake and nitrate reductase, besides nitrogenase activity (acetylene reduction) in the cyanobacteria. C. vulgaris and N. muscorum were more sensitive to carbofuran than was N. linckia. The significant toxicity of the insecticide, observed with higher concentrations of 20 and 50 μg ml−1, to nitrogenase activity in N. linckia was reversed by the addition of ATP at 10 μM. Transmission electron microscopy of the cultures, exposed to 50 μg carbofuran ml−1 showed certain cellular abnormalities, indicating interference of the insecticide with membrane properties.
16 citations
TL;DR: The data show that GA3 application can be a suitable and inexpensive way to increase N. linckia biomass and phycobiliprotein production.
Abstract: We investigated the influence of gibberellic acid (GA3; 0, 1, 10, and 100 μM) on Nostoc linckia culture at 7, 14, and 21 days. The fresh and dry weight of N. linckia was increased considerably by the 10 and 100 μM GA3 treatments. A reduction in heterocyst frequency was observed in cultures treated with 1 and 10 μM GA3. Adding GA3 to N. linckia culture had a little effect on cell size. The amount of chlorophyll a and carotenoids decreased at all concentrations of GA3. The amount of phycocyanin increased up to twofold in 7-day-old culture treated with 1 μM GA3, and similar changes were observed for allophycocyanin and phycoerythrin content after 7 days. The effect of GA3 on reducing sugar content was different and was dependent on the growth period. A reduction in soluble sugar content was detected after GA3 application in 7- and 14-day-old cyanobacteria. Cultures treated with GA3 had a higher protein content after 14 days and a lower protein content after 7 and 21 days, and reduced nitrogenase activity after 7, 14, and 21 days. Our data show that GA3 application can be a suitable and inexpensive way to increase N. linckia biomass and phycobiliprotein production.
14 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 1 |
| 2018 | 2 |
| 2016 | 2 |
| 2012 | 1 |
| 2008 | 1 |
| 2005 | 1 |