The effect of development of Taenia hydatigena larvae in the peritoneal cavity of dogs on resistance to a challenge infection with Echinococcus granulosus

Activated oncospheres of T. hydatigena within filtration membrane diffusion chambers implanted intraperitoneally into dogs developed into larvae 3 mm in dia possessing a scolex anlage without hooks. Exogenous antigens released by developing T. hydatigena larvae failed to stimulate any measurable resistance in the dogs to challenge infection with E. granulosus protoscolices.     

Isolation, Characterization, and Synthesis of AlphaFetoprotein from Neonatal Rat Brain

Monospecific anti-rat serum alpha-fetoprotein (AFP) IgG was coupled to cyanogen bromide-activated Sepharose-4B (4.5 mg/ml packed volume of gel) to yield an immunoaffinity matrix. The immunoaffinity column was used to isolate AFP from feto-neonatal rat brain. The purified AFP was immunologically and electrophoretically similar to serum AFP. It yielded a single band with a molecular weight of 70,000 on sodium dodecyl sulphate polyacrylamide gel electrophoresis. Polyacrylamide gel electrophoresis of the protein under nondenaturing conditions yielded two charge variants of AFP, reminiscent of AFP from feto-neonatal rat serum. The AFP was observed to bind estradiol with Ka = 5.8 X 10(8) M -1 and 1.3 X 10(8) M -1 by dextran-coated charcoal adsorption and Sephadex gel filtration techniques, respectively. Newborn rat brain cells linearly incorporated [14C]leucine into immunoprecipitable AFP during 6 h in culture. It is, therefore, concluded that feto-neonatal rat brain contains AFP similar to that present in fetal serum and that it may arise in brain as a result of its in situ synthesis.     

Incubation Temperature and Time Effects on Life Stages of Bursaphelenchus xylophilus in Wood Chips

Wood chips of Pinus strobus inoculated with Bursaphelenchus xylophilus were incubated at 3, 12, 30, or 40 C during intervals of 47, 82, and 130 days to determine the effects of incubation temperature and time on total number of nematodes and occurrence of each life stage. Nematodes did not survive at 40 C; the greatest number of nematodes was maintained at 3 C. The number and percentage of juveniles in the propagative cycle were greatest at 3 C after 47 days, but the percentage was greatest at 30 C after 130 days. More third-stage dispersal larvae, with percentages as high as 85%, were extracted at 3 and 12 C than at 30 C by the end of the study. Dauer larvae were extracted from the chips, but percentages never exceeded 5%. The percentage of adults was greater at 30 C than at 3 and 12 C after 82 and 130 days. When a 1-week heat treatment at 30 C was applied to samples at 3 and 12 C,. numbers and percentages of adults increased. Percentages of dauer larvae increased very slightly when the heat treatment was applied after 47 days, but numbers and percentages of juveniles and dispersals were affected erratically.     

Milk transfer of inorganic mercury to suckling rats

The transport of mercury into rat milk, and uptake in the suckling offspring was studied after peroral administration of inorganic mercury to lactating control rats, and to rats fed selenite in the diet. On day 8, 9, 10, or 11 of lactation, dams were administered a single oral dose of 0.1, 0.4, 0.7, 1.3, or 5.8 mg Hg/kg bw labeled with 203mercuric acetate. There was a linear relationship between mercury concentrations in dam's plasma and milk. The level of mercury in milk was approximately 25% of the level in plasma. After 3 d, milk levels were reduced to half the levels at 24 h. In the suckling offspring, exposed to mercury via milk during 3 d, the mercury level in blood was approximately 1% of the level in maternal blood. Mercury concentration in milk was linearly correlated to the levels in kidney, liver, and brain in the suckling offspring after 3 d exposure to mercury via milk. Selenite treatment of rats, 1.3 micrograms Se/g diet for 5 mo, resulted in increased transport of mercury to milk, probably because of increased plasma levels of mercury. However, selenite treatment of the dams did not cause any increased tissue levels of mercury in the suckling offspring.     

Localization of GABA high-affinity binding sites in the pancreas of neonatal rat

Summary The localization of gamma-aminobutyric acid (GABA) high-affinity binding sites was investigated in the exocrine and endocrine pancreas of neonatal rats by means of ³H-GABA autoradiography. GABA-binding was identified on Schwann cells and on the cells of the intralobular excretory ducts. In the endocrine part of the pancreas, no labelling was observed except in peripheral islet cells which, on the basis of their scarcity and distribution, could be somatostatin cells. Furthermore, peri-insular innervation showed considerable labelling.     

Rugiloricus bacatus sp. nov. (Loricifera ‐Pliciloricidae) and a ghost‐larva with paedogenetic reproduction

Abstract

A new species of Loricifera, Rugiloricus bacatus sp. nov. is described together with the diagnoses of two other Rugiloricus species, Rugiloricus sp. nov. A and B, from the Faroe Bank (North Atlantic). Characteristic for all three species is the presence of a new type of reduced larva, a ghost‐larva. This type of reduced larva was discovered in 1986 by Jeanne Renaud‐Mornant, but it was with the Faroe Bank material that it was first discovered that the ghost‐larvae belonged to the phylum Loricifera. The ghost‐larvae are eitherfound inside late instar Higgins‐larvae, called penultimate Higgins‐larvae, or in the sediment. The three types of Higgins‐larvae from the Faroe Bank can be distinguished by characters such as anterior setae, posterior setae and toes. The adults of Rugiloricus bacatus sp. nov. are characterised by a prominent ruff resembling a pearl necklace; two of the eight clavoscalids are modified in the 1st row; the 2nd row of leg‐shaped scalids are very large and robust, and the 9th row with 30 beak‐like scalids alternating with 30 alternating plates. The postlarvae are free‐living and their scalids on the introvert are reduced to protoscalids. Postlarvae and adult stages have not been found for Rugiloricus sp. nov. A and B and therefore only diagnoses of these two species are presented here.     

Polyplax serrata: Effects of limb disability on lousiness in mice: VI. Lack of tolerance after neonatal exposure

Mice restrained from grooming become heavily infested with lice. Ordinarily the hosts develop resistance to the infestation which results in limitation or extinction of louse populations. However, individual mice, the number depending on breed, die of anemia or, in some cases, become debilitated but survive with continuous heavy louse burdens. A similar condition of tolerance is occasionally seen in domestic animals. Experiments were conducted to determine whether heavy exposure to lice in the neonatal period could induce tolerance to the parasite. When adequate provision was made to prevent mortality from louse infestation, survival and acquisition of resistance developed at the same rate and to the same degree in neonatally exposed and in naïve mice.     

Pheromones and Nutritional Signals Regulate the Developmental Reliance on let-7 Family MicroRNAs in C. elegans

1. Download : Download high-res image (208KB)
2. Download : Download full-size image