Seasonal reproductive anatomy and sperm storage in pleurocerid gastropods (Cerithioidea: Pleuroceridae)

Life histories, including anatomy and behavior, are a critically understudied component of gastropod biology, especially for imperiled freshwater species of Pleuroceridae. This aspect of their biology provides important insights into understanding how evolution has shaped optimal reproductive success and is critical for informing management and conservation strategies. One particularly understudied facet is seasonal variation in reproductive form and function. For example, some have hypothesized that females store sperm over winter or longer, but no study has explored seasonal variation in accessory reproductive anatomy. We examined the gross anatomy and fine structure of female accessory reproductive structures (pallial oviduct, ovipositor) of four species in two genera (round rocksnail, Leptoxis ampla (Anthony, 1855); smooth hornsnail, Pleurocera prasinata (Conrad, 1834); skirted hornsnail, Pleurocera pyrenella (Conrad, 1834); silty hornsnail, Pleurocera canaliculata (Say, 1821)). Histological analyses show that despite lacking a seminal receptacle, females of these species are capable of storing orientated sperm in their spermatophore bursa. Additionally, we found that they undergo conspicuous seasonal atrophy of the pallial oviduct outside the reproductive season, and there is no evidence that they overwinter sperm. The reallocation of resources primarily to somatic functions outside of the egg-laying season is likely an adaptation that increases survival chances during winter months.

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The Relationship of Form and Function of Minute Characters of Lepidopterous Larvae, and its Importance in Life-History Studies

The Canadian Entomologist ◽

10.4039/ent96991-7 ◽

1964 ◽

Vol 96 (7) ◽

pp. 991-1004 ◽

Cited By ~ 6

Author(s):

Margaret Rae MacKay

Keyword(s):

Life History ◽

Chemical Control ◽

Life Histories ◽

The Other ◽

Taxonomic Study ◽

Form And Function ◽

Morphological Studies ◽

And Function ◽

Relationship Of ◽

The Relationship

AbstractThe information to be obtained from thorough life-history studies is an extremely useful tool, perhaps especially so when ecology is being emphasized, as it is to-day, by the life-table and other mathematical approaches to the study of population processes. This information is desired by workers in many fields of entomology – by the biological and chemical control experts, the biomathematicians, the theorists and even the taxonomists. However, much of the knowledge that these workers require, for instance the fine distinctions of behaviour and environment, has been overlooked in most life-history studies, and I strongly suspect that one of the weaknesses of studies of this nature has been the failure to analyse the mode of living of an insect (or, in the case of Lepidoptera, of the immature forms) in relation to the anatomy on one hand and environmental circumstances on the other. To look for these relationships, I believe that one requires (a) the ability and perseverance to perceive detail as minute as that required for a taxonomic study, and (b) a considerable knowledge of the taxonomic detail that is to be obtained from basic morphological studies. Therefore, in this paper, attention is drawn to pertinent structural characters of lepidopterous larvae and their probable connection with the behaviour and microhabitats of the larvae, in the hope that some guidance may be offered to future students of life-histories, at least in Lepidoptera.

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Genome-enabled discovery of evolutionary divergence in brains and behavior

Scientific Reports ◽

10.1038/s41598-021-92385-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Chinar Patil ◽

Jonathan B. Sylvester ◽

Kawther Abdilleh ◽

Michael W. Norsworthy ◽

Karen Pottin ◽

...

Keyword(s):

Reverse Genetics ◽

Natural Populations ◽

Bmp Signaling ◽

Evolutionary Divergence ◽

Genetic Changes ◽

Form And Function ◽

Brain Gene Expression ◽

Evolutionarily Conserved ◽

And Function ◽

And Behavior

AbstractLake Malawi cichlid fishes exhibit extensive divergence in form and function built from a relatively small number of genetic changes. We compared the genomes of rock- and sand-dwelling species and asked which genetic variants differed among the groups. We found that 96% of differentiated variants reside in non-coding sequence but these non-coding diverged variants are evolutionarily conserved. Genome regions near differentiated variants are enriched for craniofacial, neural and behavioral categories. Following leads from genome sequence, we used rock- vs. sand-species and their hybrids to (i) delineate the push–pull roles of BMP signaling and irx1b in the specification of forebrain territories during gastrulation and (ii) reveal striking context-dependent brain gene expression during adult social behavior. Our results demonstrate how divergent genome sequences can predict differences in key evolutionary traits. We highlight the promise of evolutionary reverse genetics—the inference of phenotypic divergence from unbiased genome sequencing and then empirical validation in natural populations.

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Ontogenetic and Phylogenetic Variation of Form and Function of the Ocular Lens

MRS Proceedings ◽

10.1557/proc-174-133 ◽

1989 ◽

Vol 174 ◽

Cited By ~ 2

Author(s):

J. G. Sivak

Keyword(s):

Refractive Index ◽

Life Histories ◽

Spherical Aberration ◽

Focal Length ◽

Relative Size ◽

Crystalline Lens ◽

Optical Quality ◽

Form And Function ◽

And Function ◽

Optical Structure

AbstractThe crystalline lens of the eye is a unique optical structure that continues to develop within the eye throughout life. This process of development results in the formation of a lens with a gradient refractive index that has important optical consequences, particularly in the control of spherical aberration. The optical characteristics of the vertebrate crystalline lens are reviewed in terms of environmental concerns and spherical aberration. Lens shape and relative size are determined by such factors as whether the eye is to be used in air or water and whether it is to be used under scotopic or photopic conditions. The continued growth of the lens through life can be related to whether the lens exhibits positive or negative spherical aberration. In general, spherical aberration, as measured using a split laser beam method with excised lenses, is minimized in species with life histories indicating superior resolution ability. In addition, lens optical quality, as indicated by zonular differences in focal length, deteriorates with lens age. While the embryonic and post-embryonic lens undergoes significant change in size, shape and refractive index distribution, it appears that focal constancy is maintained, at least in certain species. This finding may indicate a means of simplifying the process of emmetropization.

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Transcriptome programs involved in the development and structure of the cerebellum

Cellular and Molecular Life Sciences ◽

10.1007/s00018-021-03911-w ◽

2021 ◽

Author(s):

Donatella Farini ◽

Daniela Marazziti ◽

Maria Concetta Geloso ◽

Claudio Sette

Keyword(s):

Time Windows ◽

Neuronal Population ◽

Autism Spectrum ◽

Cerebellar Development ◽

Cerebellar Neurons ◽

Form And Function ◽

The Past ◽

Cerebellar Neuron ◽

And Function ◽

And Behavior

AbstractIn the past two decades, mounting evidence has modified the classical view of the cerebellum as a brain region specifically involved in the modulation of motor functions. Indeed, clinical studies and engineered mouse models have highlighted cerebellar circuits implicated in cognitive functions and behavior. Furthermore, it is now clear that insults occurring in specific time windows of cerebellar development can affect cognitive performance later in life and are associated with neurological syndromes, such as Autism Spectrum Disorder. Despite its almost homogenous cytoarchitecture, how cerebellar circuits form and function is not completely elucidated yet. Notably, the apparently simple neuronal organization of the cerebellum, in which Purkinje cells represent the only output, hides an elevated functional diversity even within the same neuronal population. Such complexity is the result of the integration of intrinsic morphogenetic programs and extracellular cues from the surrounding environment, which impact on the regulation of the transcriptome of cerebellar neurons. In this review, we briefly summarize key features of the development and structure of the cerebellum before focusing on the pathways involved in the acquisition of the cerebellar neuron identity. We focus on gene expression and mRNA processing programs, including mRNA methylation, trafficking and splicing, that are set in motion during cerebellar development and participate to its physiology. These programs are likely to add new layers of complexity and versatility that are fundamental for the adaptability of cerebellar neurons.

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Genome-enabled discovery of evolutionary divergence in brains and behavior

10.21203/rs.3.rs-275291/v1 ◽

2021 ◽

Author(s):

Chinar Patil ◽

Jonathan Sylvester ◽

Kawther Abdilleh ◽

Michael W. Norsworthy ◽

Karen Pottin ◽

...

Keyword(s):

Reverse Genetics ◽

Natural Populations ◽

Bmp Signaling ◽

Evolutionary Divergence ◽

Genetic Changes ◽

Form And Function ◽

Brain Gene Expression ◽

Evolutionarily Conserved ◽

And Function ◽

And Behavior

Abstract Lake Malawi cichlid fishes exhibit extensive divergence in form and function built from a relatively small number of genetic changes. We compared the genomes of rock- and sand-dwelling species and asked which genetic variants differed among the groups. We found that 96% of differentiated variants reside in non-coding sequence but these non-coding diverged variants are evolutionarily conserved. Genome regions near differentiated variants are enriched for craniofacial, neural and behavioral categories. Following leads from genome sequence, we used rock- vs. sand- species and their hybrids to (i) delineate the push-pull roles of BMP signaling and irx1b in the specification of forebrain territories during gastrulation and (ii) reveal striking context-dependent brain gene expression during adult social behavior. Our results demonstrate how divergent genome sequences can predict differences in key evolutionary traits. We highlight the promise of evolutionary reverse genetics – the inference of divergence in phenotype from genome sequencing in natural populations.

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Scanning tunneling microscopy (STM) of DNA and RNA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152148 ◽

1989 ◽

Vol 47 ◽

pp. 34-35

Author(s):

Patricia G. Arscott ◽

Gil Lee ◽

Victor A. Bloomfield ◽

D. Fennell Evans

Keyword(s):

Molecular Structures ◽

Inorganic Materials ◽

Resolving Power ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Form And Function ◽

Dna And Rna ◽

Calf Thymus ◽

And Function ◽

The Relationship

STM is one of the most promising techniques available for visualizing the fine details of biomolecular structure. It has been used to map the surface topography of inorganic materials in atomic dimensions, and thus has the resolving power not only to determine the conformation of small molecules but to distinguish site-specific features within a molecule. That level of detail is of critical importance in understanding the relationship between form and function in biological systems. The size, shape, and accessibility of molecular structures can be determined much more accurately by STM than by electron microscopy since no staining, shadowing or labeling with heavy metals is required, and there is no exposure to damaging radiation by electrons. Crystallography and most other physical techniques do not give information about individual molecules.We have obtained striking images of DNA and RNA, using calf thymus DNA and two synthetic polynucleotides, poly(dG-me5dC)·poly(dG-me5dC) and poly(rA)·poly(rU).

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