scholarly journals DNA content, karyotypes, and chromosomal location of 18S-5.8S-28S ribosomal loci in some species of bivalve molluscs from the Pacific Canadian coast

Genome ◽  
2000 ◽  
Vol 43 (6) ◽  
pp. 1065-1072 ◽  
Author(s):  
A M González-Tizón ◽  
A Martínez-Lage ◽  
I Rego ◽  
J Ausió ◽  
J Méndez

The DNA content of 10 species of bivalve molluscs from British Columbia coast was determined by image analysis, and the karyotypes of the horse clam Tressus capax, the bent-nose macoma Macoma nasuta, and the nuttall's mahogany clam Nuttallia nuttallii are described here for the first time. We also have analyzed the location of rDNA loci using a 28S-5.8S-18S probe in four of these species: Mytilus californianus, M. trossulus, Macoma nasuta and N. nuttallii. Results obtained report new data about cytogenetic characteristics of bivalve molluscs.Key words: Mollusca, bivalves, C-value, karyotype, ribosomal loci.

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 147
Author(s):  
Benjamin R. Jordan

Kukuiho’olua Island is an islet that lies 164 m due north of Laie Point, a peninsula of cemented, coastal, Pleistocene and Holocene sand dunes. Kukuiho’olua Island consists of the same dune deposits as Laie Point and is cut by a sea arch, which, documented here for first time, may have formed during the 1 April 1946 “April Fools’s Day Tsunami.” The tsunami-source of formation is supported by previous modeling by other authors, which indicated that the geometry of overhanging sea cliffs can greatly strengthen and focus the force of tsunami waves. Additional changes occurred to the island and arch during the 2015–2016 El Niño event, which was one of the strongest on record. During the event, anomalous wave heights and reversed wind directions occurred across the Pacific. On the night of 24–25 February 2016, large storm waves, resulting from the unique El Niño conditions washed out a large boulder that had lain within the arch since its initial formation, significantly increasing the open area beneath the arch. Large waves also rose high enough for seawater to flow over the peninsula at Laie Point, causing significant erosion of its upper surface. These changes at Laie Point and Kukuio’olua Island serve as examples of long-term, intermittent change to a coastline—changes that, although infrequent, can occur quickly and dramatically, potentially making them geologic hazards.


1998 ◽  
Vol 7 (5) ◽  
pp. 469-478 ◽  
Author(s):  
Jan P. Stegemann ◽  
John J. O'Neil ◽  
Don T. Nicholson ◽  
Claudy J.-P. Mullon

Accurate and consistent measurement of tissue volume is critical to performing many types of islet research; however, conventional visual determination of isolated islet yields through a microscope is heavily operator dependent. An improved method of islet volume determination using digital image analysis (DIA) was developed to remove operator bias and automate the islet counting process. A series of 140 porcine islet isolations were used to evaluate the DIA method in three separate stages. In Stage 1 ( n = 29 isolations), the conventional and DIA methods were correlated with two other independent islet quantitation methods: insulin extraction, and DNA extraction. It was found that volumes determined by DIA correlated more closely with insulin content and DNA content than did conventionally determined volumes. In Stages 2 and 3 ( n = 54 and 57 isolations, respectively), it was shown that an increase in the number of fields analyzed by DIA did not significantly improve the quality of the correlations. Inclusion of very small tissue (<50 fun in diameter), which is ignored in the conventional protocol affected yields by less than 10% and did not significantly improve the correlation with insulin or DNA content. Quantitation of isolated islet tissue volume using DIA has been shown to be rapid, consistent, and objective. In the laboratory, use of this method as the standard for islet volume measurement will allow more meaningful comparison of experimental results between centers. In the clinic, its use will allow more accurate dosing of transplanted tissue. © 1998 Elsevier Science Inc.


1994 ◽  
Vol 42 (11) ◽  
pp. 1413-1416 ◽  
Author(s):  
S L Erlandsen ◽  
E M Rasch

We investigated direct measurement of the DNA content of the parasitic intestinal flagellate Giardia lamblia through quantitation by Feulgen microspectrophotometry and also by visualization of Feulgen-stained DNA chromosomes within dividing cells by laser scanning confocal microscopy. Individual trophozoites of Giardia (binucleate) contained 0.144 +/- 0.018 pg of DNA/cell or 0.072 pg DNA/nucleus. Giardia lamblia cysts (quadranucleate) contained 0.313 +/- 0.003 pg DNA or 0.078 pg DNA/nucleus. The genome size (C) value per nucleus ranged between 6.5-7.1 x 10(7) BP for trophozoites and cysts, respectively. Confocal microscopic examination of Giardia trophozoites undergoing binary fission revealed five chromosome-like bodies within each nucleus. Further information about genome size and DNA content within different Giardia species may help to clarify the pivotal role of these primitive eukaryotic cells in evolutionary development.


2021 ◽  
Vol 36 (5) ◽  
pp. 596-607
Author(s):  
O. Ekşi

Abstract The aim of this study is to determine the thickness distribution of a food package using a non-destructive method. Initially, thickness measurements were carried out using an experimental procedure for thermoformed samples that were used for food packaging. Additionally, in this study, image analysis was used for the first time to determine the thickness distribution of the thermoformed products non-destructively. Image analysis software was employed for the estimation of thickness distribution. Measured thickness results were compared to those estimated using image analysis. Based on the results of the current study, image analysis may be an alternative method for non-destructive testing of thermoformed food packages even in a mass production line. Image analysis can be used to determine not only thickness distribution but also the weakest regions in a food package.


1987 ◽  
Vol 7 (1) ◽  
pp. 450-457 ◽  
Author(s):  
E H Brown ◽  
M A Iqbal ◽  
S Stuart ◽  
K S Hatton ◽  
J Valinsky ◽  
...  

We measured the temporal order of replication of EcoRI segments from the murine immunoglobulin heavy-chain constant region (IgCH) gene cluster, including the joining (J) and diversity (D) loci and encompassing approximately 300 kilobases. The relative concentrations of EcoRI segments in bromouracil-labeled DNA that replicated during selected intervals of the S phase in Friend virus-transformed murine erythroleukemia (MEL) cells were measured. From these results, we calculated the nuclear DNA content (C value; the haploid DNA content of a cell in the G1 phase of the cell cycle) at the time each segment replicated during the S phase. We observed that IgCH genes replicate in the following order: alpha, epsilon, gamma 2a, gamma 2b, gamma 1, gamma 3, delta, and mu, followed by the J and D segments. The C value at which each segment replicates increased as a linear function of its distance from C alpha. The average rate of DNA replication in the IgCH gene cluster was determined from these data to be 1.7 to 1.9 kilobases/min, similar to the rate measured for mammalian replicons by autoradiography and electron microscopy (for a review, see H. J. Edenberg and J. A. Huberman, Annu. Rev. Genet. 9:245-284, 1975, and R. G. Martin, Adv. Cancer Res. 34:1-55, 1981). Similar results were obtained with other murine non-B cell lines, including a fibroblast cell line (L60T) and a hepatoma cell line (Hepa 1.6). In contrast, we observed that IgCh segments in a B-cell plasmacytoma (MPC11) and two Abelson murine leukemia virus-transformed pre-B cell lines (22D6 and 300-19O) replicated as early as (300-19P) or earlier than (MPC11 and 22D6) C alpha in MEL cells. Unlike MEL cells, however, all of the IgCH segments in a given B cell line replicated at very similar times during the S phase, so that a temporal directionality in the replication of the IgCH gene cluster was not apparent from these data. These results provide evidence that in murine non-B cells the IgCH, J, and D loci are part of a single replicon.


Check List ◽  
2015 ◽  
Vol 11 (1) ◽  
pp. 1544 ◽  
Author(s):  
Amruta Prasade ◽  
Deepak Apte ◽  
Purushottam Kale ◽  
Otto M.P. Oliveira

The benthic ctenophore Vallicula multiformis Rankin, 1956 is recorded for the first time in the Arabian Sea, from the Gulf of Kutch, west coast of India in March 2013. This occurrence represents a remarkable extension of its geographic distribution that until now included only known the Pacific and Atlantic oceans.


1985 ◽  
Vol 38 (6) ◽  
pp. 775
Author(s):  
W Livingston

R. G. Giovanelli was appointed as a Visiting Scientist at Kitt Peak National Observatory for six months in both 1975 and 1979, and then for an entire year in 1981. These times proved fruitful to him as well as to the Observatory. The Vacuum Telescope and its 512-channel magnetograph had been completed and were operational. Complementing this was a new powerful 2D image analysis machine called the Interactive Picture Processing System (IPPS). For the first time, solar surface features could be quantitatively observed, usually to a seeing limited resolution composed of arcsec pixels, and then readily analysed as pictures. As is often the case, those who built the instruments remained preoccupied with their perfection, and it fell to Giovanelli to put these new tools to effective use. He did this in a series of research efforts reviewed in the present paper. Happily, he drew many of us in Tucson into his projects, injecting us with enthusiasm and enlarging our knowledge of solar physics in the process.


Author(s):  
O.L. Smirnova ◽  
◽  
E.A. Bessonova ◽  
T.A. Emelyanova ◽  
◽  
...  

The results of the biostratigraphic study based on the radiolarian analysis of the rhythmically layered terrigenous deposits from the Islands of the Rimsky-Korsakov Archipelago (Peter the Great Bay, Japan Sea) have been presented. These deposits are most similar to the medium-grained turbidites. For the first time the distribution and stratigraphic division of the boundary sediments of the upper Triassic and lower Jurassic separated by a marking layer were substantiated in the research area. On the basis of comparisons with isochronous zonal units of the Pacific and Tethyan areas in the upper Triassic sediments of the studied sections, layers with Globolaxtorum tozeri (upper Rhaetian) were established, and in the lower Jurassic zone Pantanellium tanuense Zone (Hettangian) was traced and layers with Parahsuum simplum (Sinemurian – Pliensbachian) were established.


Gene ◽  
1996 ◽  
Vol 168 (2) ◽  
pp. 205-209 ◽  
Author(s):  
Catherine Clabby ◽  
Usha Goswami ◽  
Fiona Flavin ◽  
Noel P. Wilkins ◽  
James A. Houghton ◽  
...  

Zootaxa ◽  
2012 ◽  
Vol 3368 (1) ◽  
pp. 91 ◽  
Author(s):  
TOMISLAV KARANOVIC ◽  
JOO-LAE CHO

Ameiridae Monard, 1927 was previously known from Korea only after one endemic and four cosmopolitan species of the genus Nitokra Boeck, 1865, and a single widely distributed species of the genus Ameira Boeck, 1865, all from brackish enviroments. After a survey of 22 sampling sites and close to 3,500 harpacticoid specimens from various marine enviroments, we report on two new endemic species of Ameira, A. zahaae sp. nov. and A. kimchi sp. nov., from the West Sea and the South Sea respectively. They are both relatively closely related to the previously recorded cosmopolitan A. parvula (Claus, 1866), but show many novel morphological structures in the caudal rami shape and ornamentation. The identity of the cosmopolitan A. parvula in Korea is questioned, and an alternative hypothesis of a species-complex proposed. The fine ornamentation of body somites (especially the pores/sensilla pattern) is studied in detail, and proves to be a very useful new morphological tool in distinguishing closely related spacies in this genus. The genus Pseudameira Sars, 1911 is reported for the first time in Korea, after four females of P. mago sp. nov. from the South Sea. A single damaged female of Proameira cf. simplex (Norman & Scott, 1905) represents the first record of the genus Proameira Lang, 1944 in Korea, Asia, and anywhere in the Pacific. A key to Korean ameirids is also provided, and their apparent rarity in this part of the world noticed.


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