Reproductive morphology of the male Tuatara,Sphenodon punctatus

Over the past decade, studies on reproductive morphology in the Squamata (snakes and lizards) have expanded tremendously. With the accumulation of these studies and revisions of the terminology based on structural similarities and differences, it is imperative to review the work on tuataras to determine whether the structural organization fits the revised terminology of vertebrates. We investigated the morphology of the male reproductive system in the Tuatara, Sphenodon punctatus (Rhynchocephalia), the sister taxon to the Squamata. Previous studies on the Tuatara used a nomenclature for the testicular ducts different from the current terminology for amniotes. The reproductive system in the Tuatara is consistent with reports in the Squamata. Two rete testis tubules exit the testis within a connective tissue sheath similar to that shown in other squamate species and the protherian Echidna. Each rete testis divides into multiple ductuli efferentes that fuse with the epididymis. The epididymis transitions into the ductus deferens where the sperm become more concentrated into spherical bundles. The ductus deferens enters the cloacal urodeum separately from the ureter. An ampulla ureter or ampulla urogenital papilla was not observed, which differs from previous studies of lepidosaurians. Furthermore, a sexual segment of the kidney (SSK) was not observed, consistent with previous studies on the Tuatara.     

Morphological changes of an inflammatory myopathy in rhesus monkeys with simian acquired immunodeficiency syndrome

Eleven of 25 rhesus monkeys which died of simian acquired immunodeficiency syndrome (SAIDS) caused by infection with a type D retrovirus related to Mason-Pfizer monkey virus showed evidence of muscle weakness and atrophy and had elevated levels of muscle enzymes. Biopsies of affected muscle studied with enzyme histochemistry showed the characteristic features of polymyositis. Inflammatory cells consisting of lymphocytes, macrophages, and large vacuolated bizarre-shaped cells of undetermined type were surrounding or invading muscle fibers and were present in the perivascular spaces and endomysia septa. Within the perivascular infiltrates, lymphocytes were abundant but very few macrophages were present. Other myopathic features including profound proliferation of fibrous tissue, necrosis, and phagocytosis of muscle fibers were noted to a variable degree. The retrovirus was isolated from affected muscles. The clinical and historical features of polymyositis in rhesus monkeys with SAIDS are very similar to those of human polymyositis. The polymyositis in SAIDS induced by a type D retrovirus related to Mason-Pfizer monkey virus is an excellent primate model to study the mechanism and morphological changes of viral-induced muscle damage.     

Phenotypic features of a strain of Yersinia pseudotuberculosis with the pVM82 plasmid, detected at pseudotuberculosis outbreak foci]

The phenotypic properties conferred to Yersinia pseudotuberculosis cells by the genetical determinants of a 25Md fragment of the plasmid pVM82 coding for the modified cellular immune response in the infected organism. The fragment was shown to determine the conjugative properties of the plasmid, the resistance of bacterial cells to a number of hydrophobic agents and cellular ability to absorb the Congo red dye. The latter confirms the presence of additional structural components in the cell wall of the strain harbouring the plasmid pVM82. The increased resistance of the plasmid-containing strain to bactericidal effect of the blood plasma was demonstrated as compared with the resistance of the strains harbouring the p57 plasmid lacking the 25Md fragment or no plasmid at all.     

Immunologic alterations in monkeys with simian acquired immunodeficiency syndrome (SAIDS)

Levels of lymphocyte responsiveness to T- and B-cell-specific mitogens and expressions of Ia, T4, T8, and T11 surface markers were monitored during the course of Simian acquired immunodeficiency syndrome (SAIDS) in four Rhesus macaques that either died or became ill and survived. The monkey that died showed progressively suppressed responses to concanavalin A (Con A), phytohemagglutinin (PHA), pokeweed mitogen (PWM), and Staphylococcus aureus Cowan I strain (SAC) through the time of death (5 1/2 weeks). For the three animals that survived, the responses of peripheral blood mononuclear cell (PBMC) to the same mitogens were decreased significantly during the period 4-6 weeks after inoculation. Levels of Ia-bearing cells in the PBMC population were markedly reduced in the moribund monkey but were not significantly decreased in the three survivors. There was no significant change in the percentage of T11-bearing cells in any of the study animals. The ratio of T4- and T8-positive cells did not vary significantly during the 18 weeks of observation in any of the animals. The infected animals showed other evidence of immunosuppression including neutropenia, lymphopenia, and depletion of lymphocytes in lymph nodes. The animal that had progressive disease and death also had Kaposi-like lesions and staphylococcal septicemia. These results indicated that in vitro evidence of immunosuppression due to SAIDS appears within a few weeks after infection and this may progress in animals that die.     

Minicultures of Mammalian Cells in a New Plastic Plate

A new disposable micro tissue culture plate was developed and tested for use in virological procedures. Miniature mammalian cell cultures (minicultures) were grown in these plates. Each plate contained 96 circular cultures in flat wells (7 mm in diameter). Replicate titrations of a number of viruses were performed in various tissues. Excellent reproducibility was demonstrated. Mean infectivity titers determined by miniculture methods were generally within 0.6 log₁₀/ml of macro tube titrations. Standard tissue culture assay techniques such as hemadsorption, interference titration, and microneutralization were easily carried out with this method and were very reproducible. Development of this noncytotoxic disposable micro tissue culture plate now permits the routine performance of rapid, reliable, and reproducible tissue culture tests at a very significant reduction in cost and labor.     

An Improved Diluent for Rubella Hemagglutination and Hemagglutination-Inhibition Tests

Rubella hemagglutinating (HA) antigen was prepared in BHK-21 tissue as 5% cell suspensions and from unconcentrated and 20× concentrated infected supernatant fluids. In some instances, unconcentrated fluids were treated with Tween 80 and ether; cell suspensions were treated with ether alone. Preparations were tested for HA activity in dextrose-gelatin-Veronal (DGV) buffer solutions; 0.85% NaCl; Sorenson's phosphate-buffered saline, pH 7.2; and a diluent of 0.9% NaCl, 0.1% CaCl₂ (anhydrous), and 0.1% MgSO₄·7H₂O. HA titers were consistently two- to fourfold higher in the saline with added Ca⁺⁺ and Mg⁺⁺ than in DGV. Hemagglutination-inhibition titers of paired human sera were the same in either diluent. It is suggested that the interaction between rubella HA antigen and the red cells of young (less than 1-day-old) chicks may be at least partially ion dependent and that titers are enhanced by increased quantities of divalent cations.     

Significant increase in natural disturbance impacts on European forests since 1950

Over the last decades, the natural disturbance is increasingly putting pressure on European forests. Shifts in disturbance regimes may compromise forest functioning and the continuous provisioning of ecosystem services to society, including their climate change mitigation potential. Although forests are central to many European policies, we lack the long-term empirical data needed for thoroughly understanding disturbance dynamics, modeling them, and developing adaptive management strategies. Here, we present a unique database of >170,000 records of ground-based natural disturbance observations in European forests from 1950 to 2019. Reported data confirm a significant increase in forest disturbance in 34 European countries, causing on an average of 43.8 million m³ of disturbed timber volume per year over the 70-year study period. This value is likely a conservative estimate due to under-reporting, especially of small-scale disturbances. We used machine learning techniques for assessing the magnitude of unreported disturbances, which are estimated to be between 8.6 and 18.3 million m³/year. In the last 20 years, disturbances on average accounted for 16% of the mean annual harvest in Europe. Wind was the most important disturbance agent over the study period (46% of total damage), followed by fire (24%) and bark beetles (17%). Bark beetle disturbance doubled its share of the total damage in the last 20 years. Forest disturbances can profoundly impact ecosystem services (e.g., climate change mitigation), affect regional forest resource provisioning and consequently disrupt long-term management planning objectives and timber markets. We conclude that adaptation to changing disturbance regimes must be placed at the core of the European forest management and policy debate. Furthermore, a coherent and homogeneous monitoring system of natural disturbances is urgently needed in Europe, to better observe and respond to the ongoing changes in forest disturbance regimes.