Differences in Ecological and Genetic Adaptations between Salamandra infraimmaculata and Ommatotriton vittatus

Israel is home to two species of amphibians belonging to distinct genera: Salamandra and Ommatotriton. They inhabit various regions, sometimes coexisting and in other instances dwelling separately across different areas, making their segregation challenging. This study compares the biological, ecological, and genetic traits of two species, the Near Eastern fire salamander Salamandra infraimmaculata and the southern banded newt Ommatotriton vittatus, to determine why O. vittatus thrives in a wider range of semi-arid habitats in central and southern Israel, whereas S. infraimmaculata predominantly occupies the coastal Mediterranean region in the north. Salamander larvae are typically found in streams, freshwater springs, and cave pools, whereas newt larvae inhabit winter pools and ponds exclusively. The developmental phase of salamander tadpoles extends over several months, whereas newt tadpoles spend a comparatively brief period in the water, from 1 to a few months. Notably, genetic disparities in the cytochrome b sequence in Israeli populations are more pronounced among newts than salamanders.

The Yellow Spot Pattern of Salamander (Salamandra infraimmaculata) in Various Habitats at the Southern Border of Its Distribution in Israel

The present study describes the different color-pattern phenotypes of yellow spots on the black back of Salamandra infraimmaculata in various habitats at the southern border of its distribution in Israel. At Tel Dan, we photographed 454 salamanders in moist habitats where water flows year round;100 of these were sampled to measure the percentage of yellow and black color on the back, and the number of spots on the head. At Kibbutz Sasa, 201 salamanders were photographed, of which 62 were sampled for the measurements. In Kibbutz Yehiam, 200 salamanders were photographed, and 60 were sampled for the measurements. At all sites, about a third of the salamanders were photographed more than once. For all three populations, yellow spots on the salamander back were found in one row, two rows or scattered. For two indices (proportion of yellow/black and number of spots on the head), the Dan population (under wet, running water all year round conditions) differed from the two other populations of salamanders (under semi-arid mountain conditions). The number of yellow spots on the head of the salamanders in the three populations varied from 1 to 7. In all populations, 4 spots pattern was the most common. In the Dan population, there were significantly more salamanders with 1 to 3 spots on their head than in the Sasa or Yehiam populations. No difference was found in the number of head spots for Sasa vs. Yehiam salamanders. The percentage of yellow on the black back was significantly larger for the Dan salamanders vs. the two other populations. The main question examined was whether there is an effect of the habitat conditions in isolated populations on the spot pattern on the salamander back. The answer is positive and is supported by previous studies.

Sex-Based Variation of Gene Expression in the Gonads and Fins of Russian Sturgeon (<i>Acipenser gueldenstaedtii</i>)

Russian sturgeon (Acipenser gueldenstaedtii) is a primitive freshwater fish and a source of black caviar. The genes involved in sexual determination and differentiation are still unknown and there are no molecular markers for sex identification in this species. Studying the variation of the sex-based differences in genomic sequences and in gene expression in the sturgeon may lead to markers of sex in early stages of development and advances in aquaculture, as well as provide novel insights about the evolution of reproduction, sex determination, and sexual differentiation mechanisms in vertebrates. Previous studies by our and other groups have identified differentially expressed genes in the gonads of adult female and male sturgeon. The current study aimed to test whether these genes were also differentially expressed in non-gonadal tissue, namely fins. We measured by qRT-PCR the mRNA levels of 29 known and novel sex-related genes in the gonads and fins of males (4 years old) and females (7 years old;sexual maturation is earlier in males than in females). Six genes (ATP6, IGFRM, LIA1A, S1A, NPL1A, GAPDH and SOX9) showed higher expression in female fins. However, only ATP6 mRNA levels differed in fins of males and females of the same age (4 years old). These findings underscore the impracticality of sex identification based on gene expression in non-gonadal tissue and the need for genetic sex markers in the Russian sturgeon.

Male Blue Gourami (Trichogaster trichopterus) Nest-Building Behavior Is Affected by Other Males and Females

In this study, we examine male blue gourami (Trichogaster trichopterus) nest-building behavior that is affected by other males and interactions under experimental conditions. Males found in the area control the territory and sexual behavior, and are influenced by the behavior of other males. The results of this study show that the sexual behavior (nest-building) of male blue gourami is affected both by the behavior and pheromones of other males. We suggest that males must defend their territories in order to prevent these two factors from interfering in nest-building.

Involvement of GnRH and Gonadotropin Genes in Oocyte Development of Blue Gourami Females (<i>Trichogaster trichopterus</i>)

The goal of this study was to gain a fundamental understanding of RnRH 1 and 3, as well as FSH and LH action, in ovarian follicles during oocyte growth by examining changes in ovarian gene transcription in blue gourami females (Trichogaster trichopterus). The levels of target ovarian mRNAs were determined by quantitative real-time PCR. GnRH1 mRNA levels were higher in oocytes at the previtellogenic stage compared to the vitellogenic and follicular oocytes maturation (FOM) stages. No significant differences in GnRH3 mRNA levels were detected among oocytes during the different stages of development. βLH and βFSH mRNA levels were lower in oocytes at the vitellogenic stage compared to the previtellogenic stage. The high transcription of GnRH 1 and 3 in the brain and of FSH and LH in the pituitary of blue gourami as was found in previous studies in our laboratory, compared to mRNA levels changed in ovary during oogenesis, supporting the hypothesis that differences exist between the function of endocrine and autocrine/paracrine of these hormones.

Ecological, Biological and Genetic Adaptation to Xeric Habitats of <i>Salamandra infraimmaculata</i>on the Southern Border of Its Distribution

In the present mini-review, published and unpublished data that have been collected for more than 40 years on the adaption of Salamandra infraimmaculata to semi-arid environments on the southern border of its distribution are presented. The contribution of the present paper is in building a model based on comparing moist habitats with predictable and relatively constant conditions to semi-arid habitats with relatively dry conditions. Based on these parameters, the model suggests adaptation to semi-arid habitats. More specifically, this model is based on the morphology, biology, behavior, life cycle and physiology of S. infraimmaculata adaptation. By considering these many parameters, one hypothesis was raised and was supported. The adaptation to and selection of semi-arid habitats depend mainly on the terrestrial phase and very little on the aquatic phases. In all of the semi-arid habitats, there are various breeding places where the larvae can grow and complete metamorphosis. The molecular genetic variation among the various areas supports our hypothesis, and the difference in the moist habitats is greater than in the semi-arid environments.

Expression of SOX3 and SOX9 Genes in Gonads of Blue Gourami

In vertebrates, SOX (SRY-related HMG box) genes are thought to be due to major gene duplication events, initially occurring during early stages of metazoan evolution and later during the transition between non-vertebrate chordates and vertebrates. The aim of this study is to examine SOX3 and SOX9 transcription in oogensis and spermatogenesis in a fish model, the blue gourami (Trichogaster trichopterus). In females during oogenesis, SOX9 mRNA levels were lower compared to SOX3 mRNA levels. In males, SOX9 mRNA levels were higher in testes compared to SOX3 mRNA levels, however no significant differences between SOX3 and SOX9 mRNA levels were observed in the gonads of males that were kept under non-reproductive conditions compared to males kept with females under reproductive conditions and that were nest-builders.

Genetic Variation among various populations of spadefoot toads (<i>Pelobates syriacus</i>, Boettger, 1869) at breeding sites in northern Israel

A genetic study was carried out on spadefoot toads (Pelobates syriacus) from habitats of various locations and altitudes in northern Israel. Cytochrome b and 12S were amplified by PCR for the analysis of genetic variation based on five DNA polymorphisms and for RAPD PCR. The nucleotide sequences of the mitochondrial DNA fragments were determined from a 460 bp clone of cytochrome b and a 380 bp clone of 12S (GenBank accession numbers, FJ595199-FJ59-5203). No genetic variation was found among the populations with regard to 12S. According to the analysis of five sequences using Arlequin software, there was a high gene identity among the populations (98.7%-99.6%). Both populations, Elrom Pond breeding site, at the highest altitude and Fara Pond, at the lowest, had the lowest identities as compared to other populations. The DNA variation among P. syri-acus populations from various breeding sites, according to band sharing (BS), when using the OP-4 primer, was 0.92-1.00. Similarity was low between the population of Elrom Pond and the populations of Kash Pond, Raihania Pond and Sasa Pond (0.92 BS), as well as between the population of Fara Pond at the lowest altitude, and the populations of Kash Pond, Raihania Pond and Sasa Pond (0.92 BS). Similar results were obtained when comparing the results obtained using primer OPA-3. The lowest similarity was found between populations of the highest altitude (Elrom Pond) and lowest altitude (Fara Pond), relative to the other ponds (Kash Pond, Raihania Pond and Sasa Pond) with a BS of 0.93.

Genetic diversity of color phenotypes in the koi (<i>Cyprinus carpio</i>L.) as identified by molecular markers

The common carp (Cyprinus carpio) has a large variety of strains. The more popular are the koi (Japanese ornamental carp), which are still bred today to generate creative colors and patterns, giving rise to multiple phenotypes. Since koi are in great demand, there is a challenge to determine the genetics defining their quality. Two methods: 1) direct sequencing of five candidate gene regions, i.e., mitochondrial (cytochrome b, 12S gene and the D-loop) and nuclear (red sensitive opsin and Rag-1) loci, to detect single nucleotide polymorphisms (SNP)s and 2) random amplification of polymorphic DNA (RAPD), were used to differentiate among four koi strains (Kohaku, Sanke, Ghost and Ohgon) and the common carp. Novel SNPs, distinguishing between koi and the common carp, were revealed in cytochrome b, the D-loop and in the red sensitive opsin;one was a missense mutation in cytochrome b at position 15860, in which threonine in the common carp became alanine in all koi strains examined. The Kohaku strain was found to have two alleles in the mitochondrial fragments, forming two different haplotypes (subpo-pulations). These novel SNPs distinguished between koi strains and the common carp, and the RAPD method enabled further differentiation among the four koi strains.

Somatolactin Transcription during Oogenesis in Female Blue Gourami (<i>Trichogaster trichopterus</i>)

Somatolactin (SL), a specific pituitary hormone belonging to the prolactin (PRL) super family, is involved in background adaptation, osmoregulation, reproduction and fatty acid metabolism. The goal of this study was to examine the gene transcription of SL changes in the ovary of blue gourami females (Trichogaster trichopterus) during oogenesis by quantitative real-time polymerase chain reaction (Real-Time PCR). Somatolactin in the pituitary was higher in females at low vitellogenesis compared to females with oocytes in maturation, and the difference was significant (p < 0.05). No significant differences were found in mRNA levels between low and high vitellogenesis, and high vitellogenesis and maturation. The findings of this and previous studies demonstrate that SL, growth hormone (GH) and PRL are involved in oogenesis in blue gourami;however, considerably more studies are required in order to separate the functions of these hormones.

Underground water affects sexual behavior and gene expression of hormones related to reproduction in blue gourami males

This study examined the effect of underground water on reproduction- and growth-related hormones in blue gourami males under non-reproductive and reproductive conditions. An increase in the percentage of males building nests under the highest percentage of underground water were compared to fish that maintained a lower percentage of underground water in the first two days. The % Gonado-somatic index (GSI) of males building nests was higher than non- reproductively active males in water containing the lowest concentration of underground water. In non- reproductively active males, brain gonadotropin releasing hormone 1 (GnRH1) and pituitary β subunit of gonadotropins (GtHs) and prolactin (PRL) mRNA levels were significantly higher in males maintained in underground water. In reproductively active males, mRNA levels of brain GnRH1, gonadotropin releasing hormone 3 (GnRH3) and pituitary PRL mRNA levels were significantly higher than males maintained in underground water. Thus, it is suggested that underground water with high salinity and conductivity levels affects the gene expression of repro- duction-related hormones;in reproductively active males, it shortened the duration of nest-building by blue gourami males.

DNA Variation of <i>Capoeta</i><i>damascina</i>(Valenciennes, 1842) in Three Rivers in Northern Israel

The present study is in agreement with the hypothesis that the variation of ecological conditions in three rivers in northern Israel—the Dan, Hasbani and Hermon Rivers—affects the genetic variations of the species Capoeta damascina. Using mitochondrial DNA (mtDNA), cytochrome b gene (Cytb), 16S and nuclear DNA (nDNA), and Random Amplified Polymorphic DNA (RAPD), four different clusters were found in the Cytb of the Hasbani and Hermon Rivers and only two in the Dan River. Moreover, the clusters in the Hasbani River differed from those found in the Hermon River. A similar result was found when an analysis was made of a different sequence from five different haplotype frequencies using the MegAlign program, the lowest being in the Dan River (only two haplotypes) and the highest in the Hasbani River (four haplotypes). The analysis of molecular variance of Cytb and 16S (AMOVA) for individuals of C. damascina from eight populations in northern Israel showed significant differences between the rivers and the populations. The analysis by mitochondrial 16S of haplotype frequencies of C. damascina populations in the rivers in northern Israel was very low compared to Ctb. Sixteen different haplotypes were found in the different rivers: eight in the Hasbani River, seven in the Dan River and only five in the Hermon River.

Genetic Variation in <i>Salamandra</i><i>infraimmaculata</i>from Different Habitats Using Amplified Fragment Length Polymorphism

The purpose of the present study was to examine the genetic variation in Salamandra infraimmaculata from different breeding site habitats using the Amplified Fragment Length Polymorphism (AFLP) method. The results of the dendogram from a hierarchical cluster analysis show that the grouping of S. infraimmaculata as cluster 5 differs from all the other clusters, including the St1 (Tel-Dan stream) population, which was the most predictable. Five Haplogroups (Hg) were characterized. The mean number of alleles per locus in each population (Ne) ranged from 10.566 (Sp1) to 2.720 (Po6). An average estimated heterozygosity (He) by population ranged from 0.100 (Po6) to 0.186 (St1). Population St1, a permanent breeding site where water was available all year round, exhibited the highest level of polymorphism, while population Po6, from the ephemeral breeding site, exhibited the lowest level of polymorphism. Gene flow between clusters showed that clusters 3 and 4 are sources of migrants and also receive gene flow, while clusters 1 and 2 may be a source of migrants but may not receive much gene flow. A phylogenetic analysis, based on clustering using Nei’s genetic distance, demonstrated that the Tel-Dan population is located on a separate branch within its sub-population. The conclusion of the present study shows that the genetic divergence among isolated populations is not correlated to distance but is affected by the variation of habitats.

Cannibalism, among Other Solutions of Adaption, in Habitats Where Food Is Not Available for Salamandra infraimmaculata Larvae Diet in Breeding Places in Xeric Habitats

The present study examines the inherent flexibility in the feeding responses of S. infraimmaculata larvae to various breeding places. In addition, the study examines the hypothesis that in dry conditions, the water breeding places are the limiting factor for the survival and completion of the life cycle of populations of S. infraimmaculata. In the breeding sites, the food for larvae is not available, and cannibalism is the specific adaptation for larvae to grow and complete metamorphosis. S. infraimmaculata larvae feed on various invertebrates in different habitats, and cannibalism involves the adaptation to breeding places where food is not available. The growth only by cannibalism as the only way to adapt to these habitats because no food is found in breeding places at the southern border of its distribution is described here for the first time, not only in salamanders but in other animals as well.

The Habitats, Burrowing Behavior, Physiology Adaptation and Life Cycle of Spadefoot Toads (<i>Pelobates syriacus, Boettge</i>r, 1869) at the Southern Limit of Its Distribution in Israel

The present study describes the habitats, life cycle, larvae growth, burrowing behavior and terrestrial adaptation of Spadefoot toads in Israel based on observations and data collected during more than 30 years in northern Israel. The distribution area in Israel is from the north in the Upper Galilee and Golan Heights (annual rainfall range of 500 - 1000 mm) to the southern coastal plain (annual rainfall of about 250 mm). Among the 51 different breeding places of amphibians, only ponds where water was available for a few months were used by Spadefoot toads and metamorphosed populations were found around these ponds. The larvae underwent metamorphosis during the summer and autumn in northern Israel, and during the spring in central and southern Israel. A negative correlation exists between the percentage of toads burrowing and soil moisture levels, with greater burrowing behavior occurring under dry conditions. The plasma concentration increased during burrowing by electrolytes and urea accumulations. The burrowing behavior helped Spadefoot toads survive in this area at the southern border of its distribution.

Damage to <i>Salamandra infraimmaculata</i>Populations by Human Activity in Creating Water Pits Is a Death Trap in Semi-Arid Habitats

The different breeding sites of Salamandra infraimmaculata on the southern border of its distribution were examined and mapped in order to estimate the damage caused by water holes that could represent death traps for salamanders in xeric habitats. Among the various types of breeding sites (springs, streams, water holes, winter pools and reservoirs), the larvae of salamanders were detected in high numbers in springs and streams (503) and water holes (48), and in relatively low numbers in winter pools. Two water holes were examined in detail to estimate the damage caused to S. infraimmaculata where breeding places are limited. During the winter, both males and females enter a water hole for breeding. The percentage of males in and around the water hole was 42% and that of females 29%. After the salamanders’ oviposition in the water, they try to return to terrestrial habitats, but are unable to do so and lose weight and die. The body mass index (BMI) of salamanders decreases from winter (December) after they move to the water hole to spring (April), when they are found in the water hole. The estimation of potential damage is about 300 mature salamanders annually.

The Effect of Light and Soil Moisture on the Environmental Behavior of Newts (<i>Triturus vittatus vittatus</i>, Urodela)

The response to hiding places of metamorphosed newts (Triturus vittatus vittatus) affected by light and moisture was studied under experimental conditions. No significant differences (X2-test;P > 0.05) were found in the choice of hiding places covered with black or transparent paper as the control of the experimental methods. The selection of hiding places by the newts is significant regarding soil moisture and negative phototoxicity. Significant differences (X2-test;P T. v. vittatus chose moist soil in hiding places covered by black or transparent paper in all the various combinations, and the difference was significant (X2-test;P < 0.001).

Sturgeon (Acipenser gueldenstaedtii) Acclimatization to Optimal Growth Conditions—A Case Study of Adaptation, Nutrition, Reproduction, and Sex Determination

The development of new agricultural industries is an important challenge for a region’s economic establishment. The connection between a research department at MIGAL Institute and biotechnology in aquaculture is an example (case study) of the interrelationships that also exist in other departments. This article describes the research conducted by the institute supporting the development of the aquaculture industry in Israel through the introduction of a relatively new fish species—the Russian sturgeon (Acipenser gueldenstaedtii), with the relevant information to be used for acclimatization to aquaculture conditions in northern Israel. Many aspects related to bringing a new species to Israel and working with this new industry to study its adaptation to existing conditions in the north of the country influenced the economic success of this new type of precision agriculture. This article describes the research on various aspects affecting the successful acclimatization of Russian sturgeon in northern Israel: introduction, food development, reproduction, hormone systems that control reproduction and growth, gonadal development, and molecular markers for sex determination, differentiation, and economic assessment of caviar production.

Changes in Tree Frog (<i>Hyla savignyi</i>) Coloration in Unstable Habitats at the Southern Border of Its Distribution

This study examined the relationship between tree frog (Hyla savignyi) coloring and its different seasonal habitats at the southern border of its distribution. The results show that tree frog color is affected by the dominant colors in its habitat, which vary seasonally, especially between winter and summer. Tree frog colors were various shades of green, white, brown, and black. No genetic marker was found to characterize the color. The ability of a small frog to infer its own time with the help of color changes occurring in the habitat on the southern border of its distribution, which are relatively broad, gives this species an advantage.

A Qualitative Model of the Interaction of Sexual Behavior and Hormone Gene Transcription in Male Blue Gourami during Reproduction

In the present study, a model is suggested to describe hormone control in male blue gourami (Trichogaster trichopterus) along the gonadotropic brain-pituitary- gonad axis (BPG axis) and the hypothalamic-pituitary-somatotropic axis (HPS axis). This model is based on the cloning and transcription of genes encoding hormones of the two axes involved in spermatogenesis during blue gourami reproduction. Gene transcription is affected by environmental, biological, and behavioral factors. Mature males were examined in two different stages—nonreproductive in high-density habitats and reproductive in low-density habitats. Based on gene transcription, gonadotropin-releasing hormone 1 (GnRH1) was involved in controlling spermatogenesis (spermatogonia to spermatids) via the BPG axis in nonreproductive and reproductive stages by controlling follicle-stimulating hormone (FSH), 11-ketotestosterone (11KT) and 17β-estradiol (E2). However, GnRH3 had a larger effect during the reproductive stage via the BPG axis (spermatids to sperm) on luteinizing hormone (LH), 11KT, and 17α-hydroxyprogesterone (17P). At the same time, the HPS axis was involved in spermatogenesis via pituitary adenylate cyclase-activating polypeptide (PACAP) and its related peptide PRP (formerly known as GHRH-like peptide) in the brain, and growth hormone (GH) in the pituitary affected synthesis of insulin-like growth factor 1 (IGF1) in the liver.