Biosynthesis of the Fungal Estrogen F-2 and a Naturally Occuring Derivative (F-3) by Fusarium moniliforme

The fungal metabolites, F-2 and F-3, associated with estrogenism in swine, are produced by some races of Fusarium moniliforme isolated from toxic feeds.     

The complete heart-lead relationship in the einthoven triangle

The relationship between the source strength and the “manifest vector” in the Einthoven Triangle is derived for a line and a point dipole source and confirmed experimentally. The result permits the interpretation of the standard ECG leads in absolute terms and corrected for body size. The manifest vector is shown to be approximately times what it would be in an otherwise similar circular slab which circumscribes the triangle.     

Effects of angiotensin blockade on the splanchnic circulation in normotensive humans

The effects of angiotensin-converting enzyme inhibition (ACE-I) by enalapril on splanchnic (n = 10) and central hemodynamics (n = 9) were examined in moderately salt-depleted healthy volunteers, at rest and during 15-20 min of lower body negative pressure (LBNP), reducing mean arterial pressure by 10 mmHg. During LBNP before ACE-I, both splanchnic and total peripheral vascular resistances increased. During ACE-I, splanchnic and total peripheral vascular resistances decreased. After enalapril administration, splanchnic vascular resistance did not increase during LBNP. Total peripheral vascular resistance still increased but not to the same extent as during LBNP before ACE-I. The increases in heart rate and plasma norepinephrine during LBNP were attenuated after ACE-I compared with LBNP before ACE-I. The effectiveness of the ACE-I was clearly demonstrated by unchanged and low plasma angiotensin II levels during ACE-I. We conclude that, in normal sodium-depleted humans, acute ACE-I decreases splanchnic vascular resistance at rest and abolishes splanchnic vasoconstriction during LBNP. Furthermore, it may interfere with autonomic nervous system control of the circulation.     

Actinocamax primus arkhangelsky (belemnitellidae; upper cretaceous) biometry,comparison and biostratigraphy

A sample ofActinocamax primus Arkhangelsky, 1912 from the Lower Middle Cenomanian limestones of the Wunstorf quarry west of Hannover (NW Germany) is studied by univariate and bivariate biometric methods in order to analyse the variation of critical characters.A. primus is closely related toA. plenus (Blainville, 1825) but differs from that species by being smaller and more slender.A. primus appears in the Lower Cenomanian and continues into the Lower Middle Cenomanian. It is mainly distributed in the northern part of the North European Palaeobiogeographic Province.A. plenus is recorded from the Middle Cenomanian-lower Lower Turonian of the Russian Platform, but only from the Middle Upper Cenomanian in NW Europe. It is widespread in the North European Province.The primus event in the Lower Middle Cenomanian and theplenus event in the Middle Upper Cenomanian are briefly discussed.     

Experimental avian PMV-2 infection in a domesticated wild host: daily behavior and effect on activity levels

Paramyxovirus type 2 (PMV-2) isolated from wild birds is often considered non-pathogenic, but nothing is known about its effects on overall behavior and fitness of free-flying birds. Domestically bred, African cut-throat finches (Amadina fasciata), a species from which PMV-2 has been isolated in the wild, were inoculated with a Central American field strain of PMV-2. Patterns of behavior were examined before and after viral challenge to quantify inapparent, sublethal effects of the disease. Infected birds demonstrated a significant decrease in activity (P = 0.01) followed by an apparent recovery period. Antibody titers confirmed infection in inoculated birds and indicated that sentinel birds did not become infected.     

Denitrification and oxygen respiration in biofilms studied with a microsensor for nitrous oxide and oxygen

Depth distributions of O₂ respiration and denitrification activity were studied in 1- to 2-mm thick biofilms from nutrient-rich Danish streams. Acetylene was added to block the reduction of N₂O, and micro-profiles of O₂ and N₂O in the biofilm were measured simultaneously with a polarographic microsensor. The specific activities of the two respiratory processes were calculated from the microprofiles using a one-dimensional diffusion-reaction model. Denitrification only occurred in layers where O₂ was absent or present at low concentrations (of a fewM). Introduction of O₂ into deeper layers inhibited denitrification, but the process started immediately after anoxic conditions were reestablished. Denitrification activity was present at greater depth in the biofilm when the NO₃ ^– concentration in the overlying water was elevated, and the deepest occurrence of denitrification was apparently determined by the depth penetration of NO₃ ^–. The denitrification rate within each specific layer was not affected by an increase in NO₃ ^– concentration, and the half-saturation concentration (K_m) for NO₃ ^– therefore considered to be low (<25M). Addition of 0.2% yeast extract stimulated denitrification only in the uppermost 0.2 mm of the denitrification zone indicating a very efficient utilization of the dissolved organic matter within the upper layers of the biofilm.     

Hemocyte monophenol oxidase activity in mosquitoes exposed to microfilariae of Dirofilaria immitis

Monophenol oxidase (MPO) activity in hemocytes collected from Aedes aegypti Liverpool strain and Aedes trivittatus intrathoracically inoculated with saline alone, inoculated with Dirofilaria immitis microfilariae (mff), or from uninoculated mosquitoes was compared using a radiometric tyrosine hydroxylation assay. Hemocyte MPO activity in mff-inoculated (= immune-activated) mosquitoes was significantly increased at 24 hr postinoculation (PI) in A. aegypti and at 6, 12, and 24 hr PI in A. trivittatus as compared with saline-inoculated controls. Baseline and immune-activated levels of hemocyte MPO activity in A. trivittatus were significantly higher compared with those seen in A. aegypti. Baseline hemocyte population levels were similar in both species, but immune activation did not elicit increases in total hemocyte populations in A. trivittatus as has been demonstrated for A. aegypti. Likewise, immune activation by the inoculation of mff did not significantly alter plasma MPO activity in A. trivittatus as compared with uninoculated or saline-inoculated mosquitoes. Plasma MPO activity in A. aegypti, however, appears to constitute a major component of the immune response. The importance of phenol oxidase(s) in the immune response of mosquitoes against mff and the relationship of observed differences in MPO activity to differences in immunological capability between A. aegypti and A. trivittatus are assessed.