Journal of experimental zoology. Part A, Ecological and integrative physiology最新文献

One neglected zoonotic illness is toxocariasis. There are not enough anthelmintic drugs in the market to treat low-effectiveness toxocariasis against migrating larvae. Therefore, it is critical to find new, safe alternatives to toxocariasis treatment today. The venom of the Leiurus quinquestratus scorpion (LQV) has numerous medicinal uses. The purpose of this study was to conduct that LQV had an effect on T. canis larvae in the model of mice. Fifty male mice were divided into five groups (n = 10). Group 1 (Gp1) was the negative group, and from Gp2-Gp5 had been infected with 800–1000 T. canis embryonated eggs. Gp2 was left as positive control, Gp3 was orally administrated with albendazole (Alb) (100 mg/kg/b.wt) for 7 consecutive days at first day post infection (pi), Gp4 was injected intra-peritoneal (i.p) with LQV (0.03 mg/kg/b.wt) for 15 consecutive days at the first day pi, and Gp5 was given Alb/LQV in the same way and doses as Gp3 and Gp4. At the end of the experiment, at 30th pi, the blood samples were collected for evaluating the biochemical and hematological parameters. The larval count reduction in brain were evaluated, and the histopathological changes in brain and liver were detected. The results showed that, treatment with LQV or Alb/LQV combinations significantly reduced the larval burden in the brain of the infected mice with reduction percentage reached to 70, and 72%, respectively. Interestingly, LQV and Alb/LQV significantly reduced IL-4, IL-10, and TNF –α levels and increased IFN-γ levels. Also, improved the liver transaminases activity, and ameliorated liver and brain architecture. Collectively, LQV may be a promising treatment for T. canis infection and albendazole alternative.

Food availability shapes morphology, physiology, growth, reproduction, and overall fitness of insects. Countless research in coccinellids reported the effect of diet in terms of quality and quantity on reproductive output. But fewer studies have reported the direct effects of food on the gonadal development in both sexes. In nature, ladybird beetle Cheilomenes sexmaculata exhibit food preference, favouring Aphis craccivora (nutritious prey) over Aphis nerii (poor prey). We hypothesized that beetles consuming nutritious prey in abundant quantity will have larger and heavier gonads. The current study assessed the effect of food preferred and its fluctuations on the gonadal development of C. sexmaculata. First instars were collected randomly from experimental stock and reared on two different diet regimes for a lifetime. After eclosion, beetles from each dietary regime were dissected daily to assess gonadal development until maturity. Here, we documented total developmental duration, body weight, weight of gonads, GSI, total area of gonads, length, and number of testicular lobules/ovarioles across different treatments. Both quality and quantity of diet significantly affected development period, body weight, and gonadal parameters in both sexes except for GSI in males and number of ovarioles in females that reared on varied diet quality, which were found to be similar. Aphis craccivora in abundant supply positively affected the growth and development of the gonads in C. sexmaculata. Beetles reared on the abundant supply of nutritious prey with larger and heavier gonads than those reared on limited supply or poor prey. This study improves our understanding of the development of gonads in ladybird beetles, which may be helpful in improving the mass rearing of ladybird beetles.

Many songbirds begin active incubation after laying their penultimate egg, resulting in synchronous hatching of the clutch except for a last-hatched individual (“runt”) that hatches with a size deficit and competitive disadvantage to siblings when begging for food. However, climate change may elevate temperatures and cause environmental incubation as eggs are laid, resulting in asynchronous hatching and larger size hierarchies among siblings. Although previous work demonstrated that asynchronous hatching reduces nestling growth and survival relative to synchrony, the physiological mechanisms underlying these effects are unclear. To test the effects of asynchronous hatching on runt growth, survival, physiology, and compensatory growth-related tradeoffs, we manipulated incubation temperature in nest boxes of European starlings (Sturnus vulgaris) to increase asynchronous hatching and collected nestling morphological measurements and blood samples to assess physiology and development. Independent of heating treatment, runts from asynchronously hatched nests had lower survival than runts from more synchronous nests. Surviving runts from asynchronous nests were smaller and had reduced stress-induced corticosterone concentrations and reduced circulating glucose compared with runts from synchronous nests. Despite persistent size and energy deficits, runts from asynchronous nests did not have significant deficits in immunity or telomere length when compared with runts from synchronous nests, suggesting no trade-off between investment in immune development or telomere maintenance with growth. Overall, these results suggest that increased asynchrony due to climate change could reduce clutch survival for altricial songbirds, especially for the smallest chicks in a clutch, and that the negative effects of asynchrony may be driven by persistent energetic deficits.

Estuaries are diverse coastal ecosystems that act as transitional zones between freshwater and seawater. The Don Hoi Lot tidal flat, located in the upper Gulf of Thailand, is one of Thailand's most important estuarine ecosystems. Nonetheless, the Don Hoi Lot area faces increasing environmental pressures due to human activities and natural changes. One of the most prominent species well-known in this area is the razor clam Solen regularis. This study investigated the effects of salinity fluctuations on the osmotic properties and antioxidant enzyme activities of the five tissues: foot, mantle, adductor muscle, gill, and digestive gland from the razor clam S. regularis collected from the Don Hoi Lot tidal flat. Razor clams were exposed to a range of salinity levels (0–35 PSU) for 7 days. The results indicated that the hemolymph osmolality of S. regularis increased with increasing salinity, demonstrating an osmoconforming pattern. Salinity changes significantly affected the activities of antioxidant enzymes (SOD, CAT, and GPX) in various tissues. In most tissues, SOD and CAT activities increased at higher salinities (30–35 PSU), while GPX activity generally increased across all tissues with increasing salinity. GST activity was not significantly affected by salinity changes. These findings suggest that S. regularis can activate antioxidant defense systems to reduce oxidative stress caused by salinity fluctuations. This study provides valuable insights into the physiological responses of S. regularis to environmental salinity changes, which can inform conservation efforts for this ecologically important species in estuarine ecosystems.

Comparative studies of reproductive biology and formation of reproductive isolation need appropriate model systems, such as groups of related species. The amphipods (Crustacea: Amphipoda) of ancient Lake Baikal are an attractive group for such works, as they consist of several hundred species that radiated within the lake and have very different levels of intraspecific genetic diversity and reproduction timing. We have previously shown that one of the most widely distributed and best studied littoral species, Eulimnogammarus verrucosus (Gersfeldt, 1858), comprises cryptic species exhibiting a post-zygotic reproductive barrier. The object of this study was Eulimnogammarus cyaneus (Dybowsky, 1874), another widespread endemic littoral Baikal species, which has a surprisingly low genetic diversity within its large geographic range. The aim of this study was to check if the populations isolated by the Angara River source, which is approximately 120-thousand years old, are reproductively compatible. As neither prezygotic nor postzygotic barriers were found, at the moment these populations should be treated as belonging to a single species. At the same time, we found some noteworthy features of reproduction of E. cyaneus. They include successive reproductive cycles with amplexuses formed by females with juveniles in the brood pouch and deposition of unfertilized eggs by females. The former might mean that this species is a relatively promising object for a laboratory culture of Baikal amphipods. Taken together, these results contribute to the establishment of a research framework to look for the correlation between genetic divergence and biological species delimitation.

Seasonally breeding animals undergo physiological and behavioral changes to time reproduction to occur during specific seasons. These changes are regulated by changing environmental conditions, which may be communicated to the brain using the central circadian clock. This clock consists of a daily oscillation in the expression of several core genes, including period (per), cryptochrome (cry), circadian locomotor output cycles kaput (clock), and basic helix-loop-helix ARNT-like protein 1 (bmal1). We began to examine seasonal regulation of four core circadian clock genes in a dissection of the reptile brain containing the hypothalamus—per1, cry1, bmal1 and clock. Our study focused on examining mRNA expression in the morning and compared levels between breeding and nonbreeding animals. We found that per1 and bmal1 mRNA expression was highest in the nonbreeding compared to breeding season in the anole hypothalamus. We also found that cry1 mRNA expression was higher in the female compared to the male anole hypothalamus. We found support for the idea that core circadian genes play a role in regulating changes between the seasons and/or sexes, although more work is needed to elucidate what processes might be differentially regulated. To our knowledge, this is the first examination of the expression of these four genes in the reptilian brain.

Maize stem borer, Chilo partellus (Swinhoe) is a key pest of maize and sorghum. It undergoes both in estivation and hibernation depending on prevailing environmental conditions. Present investigations were aimed to decipher the regulation of ecdysone, 20-hydroxyecdysone (20E) and juvenile hormone III (JH III) during different stages (prediapause, diapause and post-diapause/pupae) of hibernation and estivation as compared to counterpart nondiapause C. partellus. Significant variations were found in the ecdysone, 20E and JH III titers in the hemolymph of different stages of hibernation and estivation over the nondiapause C. partellus. At the prediapause stages of hibernation and estivation, the 20E was greater than the ecdysone. However, the ecdysone and 20E downregulated, while JH III upregulated during prediapause stages of hibernation and estivation as compared to nondiapause larvae. During diapause, 20E decreased in hibernation, and increased in estivation as compared to their respective prediapause stages. The JH III significantly upregulated in diapause stages of hibernation and estivation over the nondiapause larvae. However, it was significantly greater in prediapause and diapause stages of estivation as compared to hibernation strain. During post-diapause stage, the ecdysone and 20E titers were greater in estivation than in the hibernation and nondiapause strains, while JH III was greater in nondiapause than in the hibernation and estivation strains. These findings suggest the crucial role of these hormones in establishing switch between different stages of diapause and metamorphosis in C. partellus, which could further be useful to strategize sustainable management of C. partellus.

The present study aimed to provide comprehensive morphological features of the bronchial and parabronchial systems using cast, histological, histochemical, and scanning electron microscopy techniques, with new insights into the parabronchial topographic distribution system on 22 white Pekin ducks. Casting illustrated that the medioventral secondary bronchi (MVSB) were the largest, but the posterior (POSB) ones were the smallest. The primary (PB) and secondary bronchi (SB) were lined with thin pseudostratified, ciliated columnar epithelium. PB contained discontinuous hyaline cartilage plates interconnected by a membrane of fibrous CT with chondrocytes, while SB had mucous glands. There were two types of hexagonal parabronchi with different lumen shapes: circular in neopulmonic and longitudinal in paleopulmonic. The parabronchi had numerous atria opened into the lumen and guarded by different directed muscles: horizontal in the neopulmonic and vertical or horizontal in the paleopulmonic. The atria were lined with squamous to cuboidal cells, forming the interatrial septum (IAS). A funnel atrial duct connecting the atrium to the infundibulum can be branched. The air capillaries were nearby, at a very short distance from the blood capillaries. Despite their small number, air capillaries, which were found in parabronchi, significantly increased in size and diameter. SEM at the 4th torus level showed a parabronchi distribution with elongated paleopulmonic on the dorsomedial part, hexagonal neopulmonic on the ventrolateral part, and some neopulmonic on the medial part. The parabronchial topography distribution exhibited their unique distribution from the 1st to the 6th torus level.