Impaired postnatal development in C/EBPbeta-deficient mice

Tail DNA genotyping of fetal and neonatal mice from C/EBPbeta heterozygous parents was performed to determine whether the decreased number of surviving C/EBPbeta mutants was caused by prenatal or postnatal death. Eighty-four 3-week-old mice born of heterozygous parents had significantly lower numbers of C/EBPbeta-deficient offspring than the expected Mendelian ratio (29.8%+/+, 65.5%+/-, 4.76%-/-, P<0.05). The genotypes of 72 fetal mice from intercrossed heterozygotes showed approximately the expected 1:2:1 Mendelian ratio (18.1% +/+, 52.8% +/-, 29.2% -/-, P>0.05). No difference in the proportions by sex could be detected in these perinates. This data indicates that C/EBPbeta-deficient mice have unknown lethal problems between the embryonic stage and weaning.     

Immunochemical relationship of three antigens purified from Pasteurella multocida strain P-1059

Three antigens were prepared from a type-3 avian strain of Pasteurella multocida, and their chemical and immunologic characteristics were studied. An antigen, designated 2.5S, was extracted with 2.5% NaCl solution and purified by chromatography. Lipopolysaccharide (LPS) was extracted with phenol-water, and a third antigen, designated FS, was extracted in 0.3% formalin solution containing 0.85% NaCl and purified by differential centrifugation. The 2.5S and the FS antigens consisted of 40% protein and 15% carbohydrate, whereas LPS did not contain a substantial amount of protein. A major protein component with a molecular weight of 44,000 was detected in the 2.5S antigen, as well as in the FS antigen. Of the 3 antigens, LPS had the highest activity in mouse lethality and Limulus lysate tests. Antigenic cross-reactions among the 3 antigens were demonstrated by immunodiffusion tests. The 2.5S antigen was indistinguishable from the FS antigen, as both antigens contained the LPS component of approximately 45%. Treatments with various reagents indicated that the 2.5S and FS antigens contained at least 2 antigenic determinants. The first was a heat-stable protein sensitive to protease or phenol-water, and the second was a periodate-sensitive carbohydrate, which was a major antigenic determinant on the LPS antigen.     

Soluble fractions of Pasteurella multocida: their protective qualities against fowl cholera in turkeys

Soluble fractions of Pasteurella multocida strain P1059 were extracted from a single source by four methods, and their immunogenicity was evaluated by challenge exposure in turkeys. The fractions were extracted by 1) heating in 2.5% NaCl, 2) 0.5M potassium thiocyanate, 3) 1.0M sodium salicylate, and 4) prolonged stirring in formalin solution followed by pelleting (LPS-protein antigen). Eighty percent to 90% of infected turkeys were protected in two trials by vaccination with the saline extract or LPS-protein antigen, whereas less consistent protection was associated with the other two preparations. Endotoxin content was the highest in LPS-protein antigen, followed by KSCN, Na salicylate, and saline extract in that order. The four fractions contained at least one common antigen, which had previously been shown to be a surface-protective antigen.     

Genetic and biological characteristics ofTyphula ishikariensis isolates from Norway

Isolates ofTyphula ishikariensis, a snow mold fungus, were collected from five localities in Norway. They were divided into three groups according to genetics, cultural morphology, etc. Group I grew normally at 10 °C. Its mating patterns with Japanese taxa were variable: compatible with both biotypes A and B; compatible with biotype A but incompatible with biotype B; and incompatible with both biotypes. Group I was prevalent in southern inland districts such as Buskerud, Oppland, and Hedmark. Group II had smaller sclerotia as compared to other groups, and its sclerotia were often covered with white mycelium in nature and in culture. Group II was compatible with biotype B only. Group III was characterized by irregular growth at 10 ° C and genetic incompatibility with biotypes A and B. Cultural morphology of group III resembled that of group I at 0 °C. Rind cell patterns of sclerotia did not separate these two groups or biotypes. Isolates of groups II and III were often obtained from coastal regions in Finmark. Mating reactions were variable: monokaryons were compatible with their respective dikaryons, and monokaryons of groups II and III occasionally mated with group I dikaryons. Dikaryons of groups II and III, however did dikaryotize monokaryons of other groups. Norwegian isolates ofT. ishikariensis were highly variable, and the orthodox nomenclature system seemed inapplicalbe at the infraspecific level.     

The influence of environmental temperature,thyroid status and a synthetic oestrogen on the induction of fatty livers in chicks

1. Hepatic lipid content, lipogenic enzyme activity and plasma lipid concentration were measured in chicks reared at 21° or 34 °C and after thyroxine (T4), thiouracil (TU), propylthiouracil (PTU), dienoestrol diace‐tate (DD) or PTU with DD had been given for 14 d.

2. At 34 °C there was a significant increase in the total liver lipid and triglyceride content.

3. Injections of T4 decreased liver lipid content whereas it was increased by feeding PTU or DD. The effects of PTU were more pronounced at 21 °C while those of DD were more pronounced at 34 °C.

4. There were significant interactions between temperature, thyroid status and synthetic oestrogen treatments on total lipid and triglyceride content of the liver. Fatty liver with marked steatosis could be produced through synergic actions of PTU and DD in chicks maintained at 21 °C.     

Coleoptile cuticle of barley is necessary for the increase in appressorial turgor pressure of <Emphasis Type="Italic">Blumeria graminis</Emphasis> for penetration

To determine whether the cuticle of the barley coleoptile is responsible for a rise in appressorial turgor pressure in Blumeria graminis, we determined the appressorial turgor pressure by measuring cytorrhysis and plasmolysis in the presence of PEG6000. Appressorial turgor pressure significantly increased 13–14 h after inoculation. On the other hand, when the cuticle was completely removed from the barley coleoptile surface with diethyl ether, turgor pressure did not increase. Moreover, when we then recoated the surface with the exogenous barley cuticle fraction, appressorial turgor pressure significantly increased 12–13 h after inoculation. These results suggest that the cuticle on the surface of the barley coleoptile is necessary for the increase in the appressorial turgor pressure.     

Characterization of isolates of binucleate Rhizoctonia spp. associated with strawberry black root rot complex using fatty acid methyl ester (FAME) profiles

Black root rot is an important disease of strawberry caused by a complex of fungi that includes species of Rhizoctonia. In this study, a modified MIDI method (Microbial Identification System) was investigated for its utility to differentiate isolates of the three different anastomosis groups (AGs) of binucleate Rhizoctonia spp., associated with strawberry black root rot complex representing AG-A, AG-G, and AG-I. A total of 11 fatty acids were detected, and the FAME profiles for isolates of the three different AGs of Rhizoctonia spp. varied quantitatively and qualitatively. Moreover, the modified MIDI method will be a useful discriminatory tool for fungal identification and classification of the AGs of binucleate Rhizoctonia spp. associated with strawberry black root rot complex.     

The role of primary germ tubes (PGT) in the life cycle of Blumeria graminis: The stopping of PGT elongation is necessary for the triggering of appressorial germ tube (AGT) emergence

The conidia of Blumeria graminis f. sp. hordei (Bgh), following contact with a host surface, first form a short germ tube, called the primary germ tube (PGT), and then an elongating germ tube emerges. It differentiates into an appressorial germ tube (AGT), and then the AGT elongates and swells. It forms a hooked, appressorial lobe that penetrates the epidermal cell wall of the host. In a series of infections, the positive role of PGT in the morphogenesis of the fungus is unclear except for the possibility reported by Carver and Ingerson that the growth of a long germ tube, with the potential to differentiate into an appressorium, seems to be dependent on the perception of a suitable host surface through contact with the PGT. Therefore, the aim of the present study is to further clarify the role of PGT in the morphogenesis of the fungus. When the conidia of Bgh were inoculated onto the coleoptile surface whose cuticle was removed with cellulose acetate, the emergence of the AGT was delayed. This delay was related to the length of the PGT. That is, on the cuticleless coleoptile surface the PGT tended to continue elongating without stopping. If there were gaps on the coleoptile surface such as a cell border on the more hydrophilic substratum like cuticleless coleoptile surface, the PGT stopped elongating there and after that the AGT emerged. Moreover, the length of PGT in the beginning of AGT emergence was same as that of the PGT after appressorium formation. This means that PGT elongation had stopped when AGT began to emerge. Therefore, it is necessary to stop the PGT elongation for the triggering of AGT emergence.