Cranial morphology and adaptations in Eocene Adapidae. II. The Cambridge skull of Adapis parisiensis

One of the most complete skulls of the early primate Adapis parisiensis is in the collection of the Department of Zoology, Cambridge University. This exceptionally well-preserved male skull, from Quercy in southern France, is important in showing relatively small orbits that are highly convergent, a distinct ethmoid component in the medial orbital wall, very small infraorbital foramina, a well-preserved auditory region with the stapedial canal about twice the diameter of the canal for the promontory artery, and a well-preserved braincase 8.8 cm³ in endocranial volume. The frontal lobe of the brain in the Cambridge skull described here is less expanded than that reported previously in a British Museum skull. The average body weight of Adapis parisiensis is estimated to have been about 2.0 kg, and that of Adapis magnus is estimated to have been about 8.4 to 9.0 kg. The encephalization quotient (EQ) of Adapis parisiensis is estimated to have been 0.45, which is well below the range found in modern prosimians. There is some indication that the size of the foramen magnum has increased with increasing brain size during primate evolution. Adapis parisiensis appears to have been a medium-sized, visually oriented, diurnal, sexually dimorphic arboreal folivore.     

Conversion of Cellulose to Methane and Carbon Dioxide by Triculture of Acetivibrio cellulolyticus, Desulfovibrio sp., and Methanosarcina barkeri

The fermentation of cellulose by monocultures of Acetivibrio cellulolyticus and cocultures of A. cellulolyticus-Methanosarcina barkeri, A. cellulolyticus-Desulfovibrio sp., and A. cellulolyticus-M. barkeri-Desulfovibrio sp. was studied. The monoculture produced ethanol, acetate, H₂, and CO₂. More acetate and less ethanol was formed by the cocultures than by the monoculture. Acetate was utilized by M. barkeri in coculture with A. cellulolyticus after a lag period, whereas ethanol was metabolized by the sulfate reducer only under conditions of low H₂ partial pressure, i.e., when cocultured with A. celluloyticus-M. barkeri or when grown together with the methanogen. Only the three-component culture carried out the rapid conversion of cellulose to CO₂ and methane. Furthermore, this culture hydrolyzed the most cellulose—85% of that initially present. This amount was increased to 90% by increasing the population of M. barkeri in the triculture. Methane production was also increased, and a quicker fermentation rate was achieved.     

Phenylalanine ammonia-lyase: Purification and characterization from soybean cell suspension cultures

Soybean cell suspension cultures (Glycine max L. cv. Kanrich) grown on high-nitrogen medium produce 50 mU/g fresh wt of phenylalanine ammonia-lyase [EC 4.1.3.5] 7–9 days after inoculation. Nitrate was not limiting when the peak of enzyme activity was reached. Phenylalanine ammonia-lyase was purified 53-fold to essentially electrophoretic homogeneity from cell extracts with 10% recovery. The enzyme was stable in crude extracts and through most stages of purification. No activity could be detected with tyrosine as substrate in either crude extracts or purified enzyme. The electrophoretic mobility was somewhat less than that of the enzyme from maize but both eluted from an agarose column at the same position and the molecular weight of the subunit was similar for both enzymes. Thus the soybean enzyme is composed of four subunits and the native enzyme is ~330,000 M_r. The variation in structure and/or size and availability of hydrophobic regions among phenylalanine ammonia-lyases from four sources (potato, maize, Rhodotorula glutinis, and soybean) was shown by the different elution patterns they exhibited on columns of ω-aminoalkyl agarose (agarose-C_n-NH₂, n = 0 to 8). The order of increasing hydrophobicity is soybean, potato, maize, R. glutinis. The soybean enzyme exhibited negative cooperativity before hydroxylapatite chromatography and positive cooperativity afterward. This is the first example of positive cooperativity observed for phenylalanine ammonia-lyase.     

Enzymatic cleavage prior to antibody incubation as a method for neuropeptide immunocytochemistry

Summary Five anti-gastrin releasing peptide (GRP) sera have been characterized against GRP, bombesin and related polypeptides spotted on cellulose acetate discs. Antibodies reacting with the C-terminal G-14 sequence of bombesin and the 19–27 sequence of GRP, were detected in all sera. Antibodies directed exclsively against the bombesin unrelated 1–17 sequence of GRP were found only in one serum (R-6902). With parallel immunohistochemical tests only the C-terminal immunoreactivity was detected in endocrine-paracrine cells of the chicken proventriculus, while both immunoreactivities were present in nerve fibres and a few nerve cell bodies of the mammalian gut. The distribution of GRP- and bombesin-like immunoreactive nerves in the gastric mucosa of both pyloric and oxyntic type the submucosal and myenteric plexus along the whole gastrointestinal wall and at sphincter regions is detailed.     

The pericardium as a source of prostacyclin in the dog, ox and rat

Cyclo-oxygenase products of arachidonic acid metabolism formed by the pericardium and epicardial surface of dog heart were identified and quantitated by radioimmunoassay after separation by high-pressure liquid chromatography. Pieces of pariental pericardium, of dog, ox and rat, when incubated produced mainly 6-keto-PGF_1α, with lesser amounts of PGE₂, PGF_2α and thromboxane B₂. Biosynthesis of all prostanoids increased during incubation of the pariental pericardium of each species with arachidonic acid, but 6-keto-PGF_1α was still the major metabolite. When slices of dog heart were incubated with arachidonic acid (1 μg/ml) the rates of 6-keto-PGF_1α formation by the pariental pericardium was much greater than that of the myocardium and endocardium. Epicardial slices appeared to be intermediate in 6-keto-PGF_1α formation. The hearts of anesthetized dogs were also irrigated with Krebs' solution, and during the first 5 min of epicardial irrigation the pericardial fluid leaving the heart again contained high levels of 6-keto-PGF_1α, with lesser amounts of the other prostanoids. Addition of arachidonic acid (3 μg/ml) to the irrigating fluid caused an increase in all measured prostanoid levels, although 6-keto-PGF_1α remained the predominant metabolite. In contrast, intravenous infusion of isoproterenol selectively increased the release of 6-keto-PGF_1α from the irrigated heart. It is concluded that the pericardium and epicardium continuously release prostacyclin into the pericardial fluid, and that the increased release of this substance observed when cardiac workload increases derives mainly from these membranous sources. This raises the interesting possibility that pericardial prostacyclin might influence coronary vascular tone and chemoreflexes which arise from the epicardium during myocardial ischemia.     

Evidence for pulmonary release of 5-hydroxyeicosatetraenoic acid (5-HETE) during endotoxemia in unanesthetized sheep

Leukocyte trapping in the pulmonary circulation may be an important component of the lung vascular injury response to endotoxin, but mediators of the pulmonary leukostasis and increased lung vascular permeability are unknown. The leukocyte 5-lipoxygenation pathway of arachidonic acid metabolism yields highly biologically active products including leukotrienes C₄ and D₄ (formerly slow reacting substance of anaphylaxis) and the potent chemotaxin, leukotriene B₄. A major product of 5-lipoxygenation is 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), for which a sensitive, stable isotope dilution assay employing combined gas chromatography-mass spectrometry is available. This assay was used to test the hypothesis that 5-lipoxygenation products might participate in pulmonary vascular responses to endotoxin. We measured 5-HETE concentrations in lung lymph at three intervals during endotoxemia in unanesthetized sheep. Concentrations of 5-HETE in lung lymph exceeded those in aortic blood plasma. Lymph 5-HETE concentrations increased from 1.7±0.3 (mean ± SEM, N = 7) ng/ml during baseline to peak values of 6.1±1.8 ng/ml (p < 0.05) during the hours after endotoxemia and preceeding the steady state increased lung vascular permeability response. During the increased permeability steady state from 240 to 270 minutes after endotoxin, lymph 5-HETE concentrations (1.4±0.3 ng/ml) and lymph 5-HETE flow (i.e., 5-HETE concentration x lung lynph flow rate) returned to baseline values. Although these observations are consistent with the hypothesis that 5-lipoxygenation products participate in the pulmonary vascular injury response to endotoxin, lymph 5-HETE concentrations did not correlate with any of the other experimental measurements. It may be only coincidence that the increase in lymph 5-HETE concentrations appeared contemporaneous with the onset of lung vascular injury.     

XY female mice express H-Y antigen

Karyotypically XY individuals of the C57BL/6J-Y^POS mouse stock develop as females or hermaphrodites, but never as normal males. The aberrant sexual development results from the interaction of the C57BL/6J genetic background with the M. poschiavinus-derived Y chromosome. XY females from this stock were assayed for H-Y antigen. By the criteria of skin-grafting, the cell-mediated lympholysis test, and the popliteal lymph node assay, these XY females are antigenically indistinguishable from normal C57BL/6 males. Implications for the hypothesis that H-Y antigen induces formation of the mammalian testis are discussed.