High-Density Geometric Morphometric Analysis of Intraspecific Cranial Integration in the Barred Grass Snake (Natrix helvetica) and Green Anole (Anolis carolinensis).

How do phenotypic associations intrinsic to an organism, such as developmental and mechanical processes, direct morphological evolution? Comparisons of intraspecific and clade-wide patterns of phenotypic covariation could inform how population-level trends ultimately dictate macroevolutionary changes. However, most studies have focused on analyzing integration and modularity either at macroevolutionary or intraspecific levels, without a shared analytical framework unifying these temporal scales. In this study, we investigate the intraspecific patterns of cranial integration in two squamate species: Natrix helvetica and Anolis carolinensis. We analyze their cranial integration patterns using the same high-density three-dimensional geometric morphometric approach used in a prior squamate-wide evolutionary study. Our results indicate that Natrix and Anolis exhibit shared intraspecific cranial integration patterns, with some differences, including a more integrated rostrum in the latter. Notably, these differences in intraspecific patterns correspond to their respective interspecific patterns in snakes and lizards, with few exceptions. These results suggest that interspecific patterns of cranial integration reflect intraspecific patterns. Hence, our study suggests that the phenotypic associations that direct morphological variation within species extend across micro- and macroevolutionary levels, bridging these two scales.

Predicting the Impact of Describing New Species on Phylogenetic Patterns.

Although our inventory of Earth's biodiversity remains incomplete, we still require analyses using the Tree of Life to understand evolutionary and ecological patterns. Because incomplete sampling may bias our inferences, we must evaluate how future additions of newly discovered species might impact analyses performed today. We describe an approach that uses taxonomic history and phylogenetic trees to characterize the impact of past species discoveries on phylogenetic knowledge using patterns of branch-length variation, tree shape, and phylogenetic diversity. This provides a framework for assessing the relative completeness of taxonomic knowledge of lineages within a phylogeny. To demonstrate this approach, we use recent large phylogenies for amphibians, reptiles, flowering plants, and invertebrates. Well-known clades exhibit a decline in the mean and range of branch lengths that are added each year as new species are described. With increased taxonomic knowledge over time, deep lineages of well-known clades become known such that most recently described new species are added close to the tips of the tree, reflecting changing tree shape over the course of taxonomic history. The same analyses reveal other clades to be candidates for future discoveries that could dramatically impact our phylogenetic knowledge. Our work reveals that species are often added non-randomly to the phylogeny over multiyear time-scales in a predictable pattern of taxonomic maturation. Our results suggest that we can make informed predictions about how new species will be added across the phylogeny of a given clade, thus providing a framework for accommodating unsampled undescribed species in evolutionary analyses.

Hypocobalaminaemia as a cause of bone marrow failure and pancytopenia in a cat.

CASE REPORT: A male Domestic Short-hair cat was presented for chronic weight loss, lethargy and hyporexia. Complete haematological examination revealed non-regenerative anaemia, neutropenia and thrombocytopenia, as well as Howell-Jolly bodies, anisocytosis, polychromasia and macrocytosis on blood smear evaluation. Histopathological evaluation of bone marrow biopsy disclosed hypocellularity consistent with bone marrow failure. Concurrent hypocobalaminaemia was identified and treated with parenteral cyanocobalamin supplementation. Other differential diagnoses for pancytopenia, including infectious, toxic, immune-mediated and neoplastic causes, were ruled out. CONCLUSION: The cat's erythrocyte, leucocyte and platelet counts normalised after 2 months of cyanocobalamin supplementation, suggesting that pancytopenia may be a rare manifestation of feline cobalamin deficiency.

Differential expression of sulfotransferase enzymes involved in thyroid hormone metabolism during human placental development.

Thyroid hormone is essential for normal human development, and disruption of thyroid hormone homeostasis at critical developmental stages can result in severe and often long-term effects on crucial organs such as the brain and lungs. Numerous factors control the bioavailability of receptor active thyroid hormone T(3). Sulfation, catalyzed by sulfotransferase enzymes (SULTs), is an important pathway of thyroid hormone metabolism by which T(4) is irreversibly converted to inactive reverse T(3) rather than active T(3). The human fetus and neonate have high levels of circulating sulfated iodothyronines, although the source of these is not clear. The placenta forms the link between the fetus and its mother and is involved in transfer of thyroid hormone early in pregnancy, although its capacity for sulfation is unknown. We therefore examined expression of the SULTs involved in iodothyronine metabolism during human placental development. SULT activity was measured in human placental cotyledon and membranes (amnion, chorion, and decidua basalis) from 13-42 wk of gestation, and Western blot analysis was employed to verify enzyme activity data. Phenol and catecholamine sulfotransferases were expressed at the highest levels and were generally higher in the villous than membranous tissues. SULT1A1 activity showed significant correlation with sulfation of 3,3'-T(2), suggesting that this enzyme is primarily responsible for placental T(2) sulfation. Estrogen sulfotransferase was present at extremely low levels during early pregnancy, although in mid- and late gestation increased expression in the (predominantly maternal-derived) decidual component of the placenta was observed. Hydroxysteroid sulfotransferase, T(3), reverse T(3), and T(4) SULT activities were also low in all tissues examined, and expression of SULTs 1B1 and 1C2 were essentially undetectable by Western blot analysis. The results highlight a tissue-specific regulation of SULT expression during placental development, demonstrate very low sulfation of iodothyronines suggesting that the placenta is not a major source of circulating sulfated iodothyronines in the fetus.

Sulfation of thyroid hormone and dopamine during human development: ontogeny of phenol sulfotransferases and arylsulfatase in liver, lung, and brain.

Sulfation is an important mechanism for regulating the biological activity of numerous hormones and neurotransmitters in man. Here we have investigated the ontogeny of sulfotransferases (SULT) and sulfatase (ARS) involved in the metabolism of thyroid hormone and dopamine. SULT1A1 enzyme activity was lower in postnatal liver and lung than in fetal tissues. Hepatic SULT1A3 (dopamine) was expressed at high levels early in development, but decreased substantially in late fetal/early neonatal liver and was essentially absent from the adult liver. In lung, significant SULT1A3 activity was observed in the fetus, but neonatal levels were considerably lower. In brain, the highest activity was observed in the choroid plexus for SULT1A1, with low and widespread activity for both SULT1A1 and SULT1A3 in other brain regions. SULT activity with 3,3'-diiodothyronine (3,3'-T(2)) as substrate was measured in all tissues and correlated significantly with SULT1A1 activity (4-nitrophenol), suggesting that SULT1A1 is primarily responsible for the sulfation of this iodothyronine. The developmental expression of SULT1A3 and SULT1A1 in liver and brain was confirmed by immunoblot, and immunohistochemistry of developing liver showed substantial expression of these proteins in hemopoietic cells in fetal liver. We also detected low activity for the hydrolysis of 3,3'-T(2) sulfate by ARS, although there was less distinction between fetal and neonatal samples than with SULT activities. We have therefore shown that the developing fetus has substantial sulfation capacity. Sulfation may therefore play a major role in the homeostasis of hormones and other endogenous compounds as well as in detoxification in the fetus, particularly as other conjugating enzyme systems, such as the UDP-glucuronosyltransferases, are not expressed at significant levels until the neonatal period.

Thyroid hormone metabolism and the developing human lung.

Thyroid hormones are involved in the regulation of fetal lung development, and maturation is accelerated in animal models by antepartum exposure to raised concentrations of the receptor-active thyroid hormone triiodothyronine and glucocorticoids. It is essential that the nature of the regulation of the spatial and temporal metabolism of iodothyronines in the human fetus and infant is known before effective therapies can be developed to modify human lung maturation. Thyroid hormone bioavailability to the human fetus is regulated in part by enzymatic deiodination and reversible sulfation of iodothyronines, with contributions from other factors such as fetomaternal and fetoamniotic hormone transfers, fetal thyroid gland production, and the activities of plasma membrane transporters mediating uptake of iodothyronines from plasma into tissues.

Mechanism of diuretic-induced hypopotassemia in human hypertension.

Diuretic treatment (hydrochlorothiazide) induced a marked decrease of red cell membrane Na+K+ ATPase activity in excessive potassium loser hypertensive patients. The decreased activity occurred within 2-4 weeks of treatment and returned to baseline in 4-6 weeks after cessation of treatment. Simultaneously, red cell sodium increased, potassium decreased together with increased 24-h urinary excretion. The persistent low serum potassium may be due to impaired absorption of potassium from the gut as a result of suppressed enzyme activity since total body potassium appears also to decrease. The decreased Na+K+ ATPase activity may be due to a direct effect of the diuretic on cell membrane.

Blood pressure, electrolytes, and body size: their relationships in young relatives of men with essential hypertension.

In 154 white chldren aged 8 to 18 years from four large kindreds, relationships among blood pressure (BP), age, sex, body size, and electrolyte excretion were studied. Each kindred was ascertained through one male aged 35-58 years with essential hypertension, namely, a diastolic blood pressure (DBP) over 95 mm Hg. Weight, relative weight (relative to NCHS median for age, sex, and stature), subcutaneous fatfolds, various indices of obesity, and other measures of body size were significantly correlated with systolic blood pressure (SBP) and DBP in each sex (r = 0.3 to 0.7). Sodium and potassium excretion in 24-hour urine was also positively correlated with some measures of body size, and tended to increase with body size at a slightly more rapid rate in boys than in girls. In addition, there was a strong correlation between electrolyte excretion and BP in boys (r = 0.2 to 0.6); however, when the effects of age, body size and fatness were statistically removed, the correlations between BP and electrolyte excretion were not significant, except for 4th phase diastolic pressure (DBP4). These data, therefore, while not strongly supporting a relationship between sodium excretion and BP in children, do not rule out such a relationship, especially in families with a history of hypertension. In addition, these data provide further evidence of a very strong association between BP and body size and fatness in boys and girls.