Morphogenesis of the laminated, tripartite cytoarchitectural design of the blood-gas barrier of the avian lung: a systematic electron microscopic study on the domestic fowl, Gallus gallus variant domesticus

Formation of a thin blood-gas barrier in the respiratory (gas exchange) tissue of the lung of the domestic fowl, Gallus gallus variant domesticus commences on day 18 of embryogenesis. Developing from infundibulae, air capillaries radiate outwards into the surrounding mesenchymal (periparabronchial) tissue, progressively separating and interdigitating with the blood capillaries. Thinning of the blood-gas barrier occurs by growth and extension of the air capillaries and by extensive disintegration of mesenchymal cells that constitute transient septa that divide the lengthening and anastomosing air capillaries. After they contact, the epithelial and endothelial cells deposit intercellular matrix that cements them back-to-back. At hatching (day 21), with a thin blood-gas barrier and a large respiratory surface area, the lung is well prepared for gas exchange. In sites where air capillaries lie adjacent to each other, epithelial cells contact directly: intercellular matrix is lacking.     

The voltage-dependent anion channel is a receptor for plasminogen kringle 5 on human endothelial cells

Human plasminogen contains structural domains that are termed kringles. Proteolytic cleavage of plasminogen yields kringles 1-3 or 4 and kringle 5 (K5), which regulate endothelial cell proliferation. The receptor for kringles 1-3 or 4 has been identified as cell surface-associated ATP synthase; however, the receptor for K5 is not known. Sequence homology exists between the plasminogen activator streptokinase and the human voltage-dependent anion channel (VDAC); however, a functional relationship between these proteins has not been reported. A streptokinase binding site for K5 is located between residues Tyr252-Lys283, which is homologous to the primary sequence of VDAC residues Tyr224-Lys255. Antibodies against these sequences react with VDAC and detect this protein on the plasma membrane of human endothelial cells. K5 binds with high affinity (Kd of 28 nm) to endothelial cells, and binding is inhibited by these antibodies. Purified VDAC binds to K5 but only when reconstituted into liposomes. K5 also interferes with mechanisms controlling the regulation of intracellular Ca2+ via its interaction with VDAC. K5 binding to endothelial cells also induces a decrease in intracellular pH and hyperpolarization of the mitochondrial membrane. These studies suggest that VDAC is a receptor for K5.     

Morphology and morphometry of the normal lung of the adult vervet monkey (Cercopithecus aethiops)

The lungs of four adult specimens of the vervet monkey (Cercopithecus aethiops) have been examined by transmission and scanning electron microscopy. A morphometric evaluation of the structural components directly involved in gas exchange has been carried out and the data have been modelled to estimate the anatomical diffusing capacity of the lung. The upper air-conducting airways of the lung were lined by an epithelium characterized by ciliated cells among which were dispersed goblet cells. The alveolar surface was lined by squamous type I pneumocytes and cuboidal type II granular pneumocytes. The blood-gas (tissue) barrier consisted of an epithelial cell, a common basal lamina, and an endothelial cell in the thin parts of the interalveolar septum. In the thicker parts of the septum, an interstitial space interposed between the basal laminae of the epithelial and endothelial cells contained supportive elements such as collagen, elastic tissue, and fibrocytes. The alveoli, the blood capillaries, and septal tissue composed 73%, 16%, and 11%, respectively, of the parenchyma. The harmonic and arithmetic mean thicknesses of the blood-gas (tissue) barrier were 0.311 micron and 1.048 microns; the surface area of the blood-gas (tissue) barrier per unit body weight was 50 cm2g-1, and the surface density was 117 mm2.mm3-1. The weight-specific total morphometric diffusing capacity was 0.11 mlO2 (sec.mbar.kg)-1. In comparison, the pulmonary morphometric characteristics of vervet monkey lung were superior to those of the other primates (Macaca irus, M. mulatta, and Homo sapiens) for which equivalent data are available. The gas-exchange potential of the lungs of the nonhuman primates as revealed by morphometric studies surpasses that of man, a feature that can be attributed to the relatively less energetic human lifestyle.     

Growth of Cryptococcus neoformans in a thiamine-free medium

The growth of Cryptococcus neoformans in a minimal liquid synthetic medium with or without thiamine (10 g/ml) was investigated. In these media the presence or absence of thiamine had no effect on the development of C. neoformans. To check these results, we performed a series of experiments on a solid form of the minimal synthetic medium. In this study a series of six serial transfers were carried out to starve the cells of nutrients that may have been carried over from their growth on rich media. In each of the transfers on the solid synthetic medium, C. neoformans showed a similar and scarce growth. This finding indicates that C. neoformans could be autotrophic in respect to thiamine.     

Hydrocortisone increases the number of receptors for thyrotropin-releasing hormone on pituitary cells in culture.

Hydrocortisone (cortisol) increased the binding of thyrotropin-releasing hormone (TRH) to specific membrane receptors in 4 clonal strains of rat pituitary cells. At the highest effective cortisol concentration (3–5 × 10^?6 M), the increase was observed within 6–8 hr and became maximal (140 to 160% of control binding) by 18–24 hr. Half-maximum stimulation occurred in serum-containing medium at 9 × 10^?8 M cortisol, and a significant increase in TRH binding was seen at 3 × 10^?8 M. Equilibrium binding studies showed that enhanced TRH binding was explained by an increase in receptor number with no change in affinity. Similar effects were seen with Dexamethasone, but no increase in TRH binding was noted when testosterone, methyltestosterone, progesterone, estradiol or the antiestrogen Lilly 88571 were added to the culture medium. Cortisol treatment did not cause the appearance of specific TRH binding sites in cell strains previously shown to lack receptors for the tripeptide (F₄C₁, GH₁2C₁ and R₅ cells). When added cortisol was removed from medium, receptor number decayed to control values with a $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ of about 30 hr. Previous studies have shown that TRH receptors in GH-cells can be down-modulated by TRH and thyroid hormones; the present findings demonstrate that glucocorticoid hormones can increase the number of TRH receptors in GH-cells.     

Modeling Reef Fish Biomass,Recovery Potential,and Management Priorities in the Western Indian Ocean

Fish biomass is a primary driver of coral reef ecosystem services and has high sensitivity to human disturbances, particularly fishing. Estimates of fish biomass, their spatial distribution, and recovery potential are important for evaluating reef status and crucial for setting management targets. Here we modeled fish biomass estimates across all reefs of the western Indian Ocean using key variables that predicted the empirical data collected from 337 sites. These variables were used to create biomass and recovery time maps to prioritize spatially explicit conservation actions. The resultant fish biomass map showed high variability ranging from ~15 to 2900 kg/ha, primarily driven by human populations, distance to markets, and fisheries management restrictions. Lastly, we assembled data based on the age of fisheries closures and showed that biomass takes ~ 25 years to recover to typical equilibrium values of ~1200 kg/ha. The recovery times to biomass levels for sustainable fishing yields, maximum diversity, and ecosystem stability or conservation targets once fishing is suspended was modeled to estimate temporal costs of restrictions. The mean time to recovery for the whole region to the conservation target was 8.1(± 3SD) years, while recovery to sustainable fishing thresholds was between 0.5 and 4 years, but with high spatial variation. Recovery prioritization scenario models included one where local governance prioritized recovery of degraded reefs and two that prioritized minimizing recovery time, where countries either operated independently or collaborated. The regional collaboration scenario selected remote areas for conservation with uneven national responsibilities and spatial coverage, which could undermine collaboration. There is the potential to achieve sustainable fisheries within a decade by promoting these pathways according to their social-ecological suitability.     

Mitochondrial‐targeted catalase is good for the old mouse proteome,but not for the young: ‘reverse’ antagonistic pleiotropy?

Reactive oxygen species (ROS) are highly reactive oxygen‐containing molecules associated with aging and a broad spectrum of pathologies. We have previously shown that transgenic expression of the antioxidant enzyme catalase targeted to the mitochondria (mCAT) in mice reduces ROS, attenuates age‐related disease, and increases lifespan. However, it has been increasingly recognized that ROS also has beneficial roles in signaling, hormesis, stress response, and immunity. We therefore hypothesized that mCAT might be beneficial only when ROS approaches pathological levels in older age and might not be advantageous at a younger age when basal ROS is low. We analyzed abundance and turnover of the global proteome in hearts and livers of young (4 month) and old (20 month) mCAT and wild‐type (WT) mice. In old hearts and livers of WT mice, protein half‐lives were reduced compared to young, while in mCAT mice the reverse was observed; the longest half‐lives were seen in old mCAT mice and the shortest in young mCAT. Protein abundance of old mCAT hearts recapitulated a more youthful proteomic expression profile (P‐value < 0.01). However, young mCAT mice partially phenocopied the older wild‐type proteome (P‐value < 0.01). Age strongly interacts with mCAT, consistent with antagonistic pleiotropy in the reverse of the typical direction. These findings underscore the contrasting roles of ROS in young vs. old mice and indicate the need for better understanding of the interaction between dose and age in assessing the efficacy of therapeutic interventions in aging, including mitochondrial antioxidants.     

Hematological changes in vervet monkeys (Chlorocebus aethiops) during eight months' adaptation to captivity

This study investigated fluctuations in hematological values of 50 wild-caught vervet monkeys (African green monkeys, grivets, Chlorocebus aethiops) during habituation to captivity. The monkeys were categorized into four groups according to age and sex viz adult males, adult females, juvenile males, and juvenile females. The erythrocyte values were significantly higher (P<0.05) in the adult males than in the other animals. There was an increase in most of the erythrocyte parameters studied during the monitoring period with the most significant being hemoglobin, hematocrit, and mean corpuscular volume. However, the red cell distribution widths, which were higher in adult females, declined. The total white blood cell (WBC) counts, which were higher in adult females than in the other animals, were closely correlated with granulocytes counts. The WBC levels decreased in all the animals throughout the 8 months study, indicating gradually decreasing stress, but they were relatively stable in males. The platelet counts declined significantly (P<0.05) and at 8 months post capture the counts were higher in females than in males. The juvenile female platelet counts were relatively stable during the monitoring period. The maintenance of the monkeys on an improved stable diet and in environment-controlled housing combined with progressing psycho-physiological adaptation may be important factors for the gradual improvements of the hematological values recorded. There were wide variations in these between individual animals emphasizing the need for long adaptation combined with establishment of individual baseline values before experimental studies.