Ultrastructure of spermatophoral sperm in the freshwater gastropod Thiara amarula (Linnaeus, 1758) (Cerithioidea: Thiaridae): potential taxonomic features including eusperm nuclear content differentiation

AbstractMicroRNAs (miRNAs) are a deeply conserved class of small, single stranded RNA molecules that post-transcriptionally regulate mRNA levels via several targeted degradation pathways. They are involved in a wide variety of biological processes and have been used to infer the deep evolutionary relationships of major groups such as the Metazoa. Here we have surveyed several adult tissues of the freshwater pulmonate Lymnaea stagnalis (the Great Pond Snail) for miRNAs. In addition we perform a shell regeneration assay to identify miRNAs that may be involved in regulating mRNAs directly involved in the shell-forming process. From seven mature tissues we identify a total of 370 unique precursor miRNAs that give rise to 336 unique mature miRNAs. While the majority of these appear to be evolutionarily novel, most of the 70 most highly expressed (which account for 99.8% of all reads) share sequence similarity with a miRBase or mirGeneDB2.0 entry. We also identify 10 miRNAs that are differentially regulated in mantle tissue that is actively regenerating shell material, 5 of which appear to be evolutionarily novel and none of which share similarity with any miRNA previously reported to regulate biomineralization in molluscs. One significantly down-regulated miRNA is predicted to target Lst-Dermatopontin, a previously characterized shell matrix protein from another freshwater gastropod. This survey provides a foundation for future studies that would seek to characterize the functional role of these molecules in biomineralization or other processes of interest.

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Changes in nuclear content of protein conjugate histone H2A-ubiquitin during rooster spermatogenesis

FEBS Letters ◽

10.1016/0014-5793(82)80604-2 ◽

1983 ◽

Vol 155 (2) ◽

pp. 209-212 ◽

Cited By ~ 35

Author(s):

Neus Agell ◽

Manel Chiva ◽

Cristóbal Mezquita

Keyword(s):

Histone H2a ◽

Protein Conjugate ◽

Nuclear Content

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Histochemical studies of dopa oxidase and peroxidase in the mantle-edge of the freshwater gastropod, Helisoma duryi eudiscus (Pilsbry)

Canadian Journal of Zoology ◽

10.1139/z68-026 ◽

1968 ◽

Vol 46 (2) ◽

pp. 165-167 ◽

Cited By ~ 5

Author(s):

S. P. Kapur ◽

M. A. Gibson

Keyword(s):

Positive Reaction ◽

Protein Component ◽

Negative Reaction ◽

Structural Proteins ◽

Freshwater Gastropod ◽

Helisoma Duryi ◽

Mantle Edge ◽

Dopa Oxidase ◽

Oxidase Reaction

The mantle-edge gland produces the highly tanned, densely fibrous periostracum, and the cubocolumnar cells contribute to the deposition of the less highly tanned matrix of the inner shell layers. The mantle-edge gland gives positive reactions for dopa oxidase and peroxidase, but does not contain melanin. The cubocolumnar cells reveal a positive reaction for dopa oxidase, possess numerous melanin granules, and exhibit a negative reaction for peroxidase. It is suggested that quinones may contribute to the process of tanning and hardening of the structural proteins of the shell. The dopa oxidase reaction within the cubocolumnar cells indicates the presence of tyrosine and suggests that these cells are capable of producing quinones to color and harden the protein component of the inner shell layers. It also explains the abundance of melanin granules within these cells. Within the mantle-edge gland, it is suggested that the peroxidase inhibits the formation of melanin from dopa quinone, and peroxidase, by accentuating quinone production, may cause further hardening of the periostracum.

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Inorganic nuclear content as an index of tumour radiosensitivity

The Journal of Pathology and Bacteriology ◽

10.1002/path.1700480102 ◽

1939 ◽

Vol 48 (1) ◽

pp. 1-10 ◽

Cited By ~ 4

Author(s):

I. A. B. Cathie

Keyword(s):

Nuclear Content

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First freshwater gastropod preserved in amber suggests long-distance dispersal during the Cretaceous Period

Geological Magazine ◽

10.1017/s0016756821000285 ◽

2021 ◽

pp. 1-8

Author(s):

Tingting Yu ◽

Thomas A. Neubauer ◽

Adrienne Jochum

Keyword(s):

New Species ◽

Freshwater Snail ◽

Aquatic Biota ◽

Long Distance Dispersal ◽

Long Distance ◽

Burmese Amber ◽

Freshwater Gastropod ◽

The Family ◽

Cretaceous Period ◽

Globally Distributed

Abstract Burmese amber continues to provide unique insights into the terrestrial biota inhabiting tropical equatorial forests during mid-Cretaceous time. In contrast to the large amount and great diversity of terrestrial species retrieved so far, aquatic biota constitute rare inclusions. Here we describe the first freshwater snail ever preserved in amber. The new species Galba prima sp. nov. belongs in the family Lymnaeidae, today a diverse and near globally distributed family. Its inclusion in terrestrial amber is probably a result of the amphibious lifestyle typical of modern representatives of the genus. The finding of a freshwater snail on the Burma Terrane, back then an island situated at some 1500 km from mainland Asia, has implications for the dispersal mechanisms of Mesozoic lymnaeids. The Cenomanian species precedes the evolution of waterfowl, which are today considered a main vector for long-distance dispersal. In their absence, we discuss several hypotheses to explain the disjunct occurrence of the new species.

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Freshwater gastropod communities in eastrn Brittany (France)

Journal of Molluscan Studies ◽

10.1093/mollus/60.4.467 ◽

1994 ◽

Vol 60 (4) ◽

pp. 467-471 ◽

Cited By ~ 4

Author(s):

Katherine Costil

Keyword(s):

Freshwater Gastropod

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First record of subterranean rissoidean gastropod assemblages in Southeast Asia (Mollusca, Gastropoda, Pomatiopsidae)

Subterranean Biology ◽

10.3897/subtbiol.25.23463 ◽

2018 ◽

Vol 25 ◽

pp. 9-34

Author(s):

Jozef Grego

Keyword(s):

Southeast Asia ◽

New Genus ◽

First Record ◽

Karst Spring ◽

Gastropod Species ◽

The Third ◽

Freshwater Gastropod

In February 2017 we investigated several caves and karstic springs in Laos for the presence of underground freshwater gastropod species. We report previously unrecorded freshwater gastropod assemblages in the largest cave in Laos, Tham Khon Dôn, and in the third largest cave, Pha Soung, in Khammouane Province, with single finds in Na Li Cave (Khammouane Province), an unnamed cave near Vieng Thong (Bolikhamsay Province) and a small karst spring near Phonsavan (Xianghouan Province). All 15 species recorded and described herein are new to science. Four species are assigned to the new genus Pseudoiglica: P. pseudoiglica sp. n., P. olsavskyi sp. n., P. kameniari sp. n., and P. phonsavanica sp. n. Three species are assigned to the new genus Thamkhondonia: T. moureti sp. n., T. vacquiei sp. n., and T. smidai sp. n. Eight species are assigned to the genus Tricula Benson, 1843: T. valenasi sp. n., T. davisi sp. n., T. spelaea sp. n., T. lenahani sp. n., T. reischuetzorum sp. n., T. phasoungensis sp. n., T. bannaensis sp. n., and T. viengthongensis sp. n.

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