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An experimental model of hypothyroidism was obtained by thyroidectomy. The operation was carried out on 57 sexually mature male rats weighing 250–300 g. The experiment lasted 45 days. Laboratory animals were removed from the experiment on days 7th, 14th, 21st, 28th, 35th and 45th. As a control, 15 rats were used that were not operated on. For histological examination, pieces of rat myocardium were taken from the left and right ventricles. The pieces were fixed in 10% buffered formalin for 10 days. Histological sections were prepared in a standard manner. Sections were stained with hematoxylin and eosin, picrofuchsin according to van Gieson, toluidine blue, according to Mallory. Results of the study: In the myocardium of rats, hemodynamic disorders, edema, hydropic degeneration of cardiomyocytes, myocytolysis, fragmentation of muscle fibers, colliquation necrosis, compression and atrophy of muscle fibers were found. An immunohistochemical study revealed a decrease in the expression of desmin and sarcomeric actin.

Medullary bone is a calcium-rich, labile bone normally occurring in female birds with each egg-laying cycle. The stimulus for formation of medullary bone is, in part, the cyclic increase in serum estrogens produced by preovulatory ovarian follicles. Increased bone density due to formation of medullary bone, particularly in pneumatic bones, has been termed polyostotic hyperostosis, even if physiologic. This study investigated the formation of medullary bone in nonpneumatic (femur) and pneumatic (humerus) bones in sexually mature male budgerigars submitted for autopsy. Of the 21 sexually mature male budgerigars submitted for autopsy, 7 (33%) had medullary bone in 1 or more bones examined. All 7 male budgerigars with medullary bone had a testicular neoplasm, which was morphologically consistent with a testicular sustentacular cell tumor, seminoma, or interstitial cell tumor. Medullary bone was not present in the 14 cases with other diseases. Medullary bone formation in pneumatic and nonpneumatic bones can occur in male budgerigars with testicular neoplasms. Radiographic increases in medullary bone density, particularly in the humerus, could provide antemortem indication of testicular neoplasia in male budgerigars.

The purpose of the study was to study the morphofunctional rearrangements of the structural components of the adenohypophysis of sexually mature male rats under the condition of a 30-day period of readaptation to the long-term influence of salts of heavy metals (zinc, copper, iron, manganese, lead and chromium) and taking a corrector drug. Materials and methods. The experiment was carried out on 24 white sexually mature male rats, which were divided into 1 control and 1 experimental group. The experimental group consisted of rats that consumed ordinary drinking water for 30 days after 90 days of receiving water saturated with a combination of heavy metal salts: zinc (ZnSO4 7H2O) – 5 mg / l, copper (CuSO4 5H2O) mg / l, iron (FeSO4) – 10 mg / l, manganese (MnSO4 5H2O) – 0.1 mg / l, lead (Pb (NO3) 2) – 0.1 mg / l and chromium (K2Cr2O7) – 0.1 mg / l and L-tocopherol corrector. Results and discussion. With a 30-day period of readaptation to the action of a complex of salts of heavy metals, combined with the intake of a corrector drug L-tocopherol, morphological rearrangements of a nonspecific polymorphic nature developed in the structural components of the pituitary gland: compensatory hypertrophy and increased vascularization of the pituitary gland were observed, the state of rheological properties of the blood improved, the number of chromophiles increased and the number of chromophobes decreased, the processes of cyst formation disappeared, the stress from the adaptive processes in the glandulocytes of the adenohypophysis decreased, namely their secretory activity, the expression of Hsp90α receptors in the cytoplasm of adenocytes significantly increased. Negative rearrangements include an increased value of the fibrous component of the connective tissue of the intertrabecular spaces, increased collagenization of the wall of veins and capillaries, preservation of stromal edema, plethora of hemocapillaries, the presence of a small number of adenocytes with signs of vacuolization of the cytoplasm, balloon dystrophy. Conclusion. A comprehensive study of the structural components of the adenohypophysis of the test animals under the condition of a 30-day period of readaptation to long periods of consumption of heavy metal salts and correction with L-tocopherol certainly indicate a number of adaptive and regenerative morphofunctional changes aimed at reducing the stress of adaptive processes on the part of the adenohypophysis in response to cancel the action of the stress factor

Abstract Background The salmon shark (Lamna ditropis) is a widely distributed apex predator in the North Pacific Ocean. Many salmon sharks from the eastern North Pacific, specifically Prince William Sound, Alaska, have been satellite tagged and tracked, but due to the sexual segregation present in salmon sharks, most of these tagged sharks were female. Consequently, little information exists regarding the migration patterns of male salmon sharks. To better understand the migration and distribution of this species, information on the male component of the population as well as from sharks outside of Prince William Sound, Alaska, is needed. In this study, we deployed satellite transmitters on two mature male salmon sharks caught in the Bering Sea. Results The two mature male salmon sharks tagged in the Bering Sea exhibited distinct migration patterns. The first male, tagged in August 2017, traveled to southern California where it remained from January to April after which it traveled north along the United States’ coast and returned to the Bering Sea in August 2018. The second male, tagged in September 2019, remained in the North Pacific between 38° N and 50° N before returning to the Bering Sea in July of year one and as of its last known location in year two. The straight-line distance traveled by the 2017 and 2019 sharks during their 12 and 22 months at liberty was 18,775 km and 27,100 km, respectively. Conclusions Before this study, our understanding of salmon shark migration was limited to female salmon sharks satellite tagged in the eastern North Pacific. The 2017 male salmon shark undertook a similar, but longer, north–south migration as tagged female sharks whereas the 2019 shark showed little overlap with previously tagged females. The different migration patterns between the two male sharks suggest distinct areas exist for foraging across the North Pacific. The return of both sharks to the Bering Sea suggests some fidelity to the region. Continued tagging efforts are necessary to understand the population structure of salmon sharks in the North Pacific. This tagging study highlights the importance of opportunistic efforts for obtaining information on species and sex with limited distribution data.

Mature male mice produce a particularly high concentration of major urinary proteins (MUPs) in their scent marks that provide identity and status information to conspecifics. Darcin (MUP20) is inherently attractive to females and, by inducing rapid associative learning, leads to specific attraction to the individual male’s odour and location. Other polymorphic central MUPs, produced at much higher abundance, bind volatile ligands that are slowly released from a male’s scent marks, forming the male’s individual odour that females learn. Here, we show that infection of C57BL/6 males with LCMV WE variants (v2.2 or v54) alters MUP expression according to a male’s infection status and ability to clear the virus. MUP output is substantially reduced during acute adult infection with LCMV WE v2.2 and when males are persistently infected with LCMV WE v2.2 or v54. Infection differentially alters expression of darcin and, particularly, suppresses expression of a male’s central MUP signature. However, following clearance of acute v2.2 infection through a robust virus-specific CD8 cytotoxic T cell response that leads to immunity to the virus, males regain their normal mature male MUP pattern and exhibit enhanced MUP output by 30 days post-infection relative to uninfected controls. We discuss the likely impact of these changes in male MUP signals on female attraction and mate selection. As LCMV infection during pregnancy can substantially reduce embryo survival and lead to lifelong infection in surviving offspring, we speculate that females use LCMV-induced changes in MUP expression both to avoid direct infection from a male and to select mates able to develop immunity to local variants that will be inherited by their offspring.

The collection of adults, mature male pupae, and the absence of confusing species at the sampling sites located in the Cevennes and French Alps enabled descriptions of the hitherto unknown larvae of Plectrocnemia cevennensis Coppa 2011 and P. praestans McLachlan 1884 (Trichoptera, Polycentropodidae). We present information on the morphology of the larvae and illustrate the most important diagnostic features. In the context of the larval key to European Plectrocnemia species by Waringer & Graf (2020), P. cevennensis keys together with P. scruposa McLachlan 1880, whereas P. praestans keys with P. conspersa (Curtis 1834). These two species pairs are morphologically very close; P. cevennensis and P. scruposa can be separated by the numbers of secondary setae on the last abdominal sternum, but the separation of P. praestans and P. conspersa is not always possible.

Male walruses produce some of the longest continuous reproductive displays known among mammals to convey their physical fitness to potential rivals and possibly to potential mates. Here, we document the ability of a captive walrus to produce intense, rhythmic sounds through a non-vocal pathway involving deliberate, regular collision of the fore flippers. High-speed videography linked to an acoustic onset marker revealed sound production through cavitation, with the acoustic impulse generated by each forceful clap exceeding a peak-to-peak sound level of 200 dB re. 1 µPa. This clapping display is in some ways quite similar to the knocking display more commonly associated with walruses in rut but is produced through a very different mechanism and with much higher amplitudes. While this clapping behaviour has not yet been documented in wild individuals, it has been observed among other mature male walruses living in human care. Production of intense sounds through cavitation has previously been documented only in crustaceans but may also be an effective means of sound production for some aquatic mammals.