The antagonism of bombesin in the CNS by substance P analogues

The ability of substance P analogues to inhibit the action of bombesin in the CNS was investigated using receptor binding and biological assays. The putative substance P antagonists inhibited binding to central receptors for both substance P and bombesin-like peptides. Spantide, which was the most potent analogue tested, reversed the bombesin induced hypothermia and grooming. Therefore the putative substance P antagonists may also antagonize the actions of bombesin in the CNS     

The spinning apparatus of Polenecia producta (Araneae,Uloboridae): Structure and histochemistry

Summary The spinning apparatus of the uloborid spider Polenecia producta was studied to complete previous studies on the same family of spiders. The structure of spinnerets and spigots, under scanning electron microscopy, and the main anatomical and histochemical characteristics of the spinning glands of adult females and males are described. In addition some observations on the spinning apparatus at three successive stages of development are made. There are nine kinds of silk glands in Polenecia, i.e. one more (aciniform — B glands) than found in other uloborids. The spinning apparatus of Polenecia is, therefore, the most complex so far known. It is also more complex than that presently known of Araneoidea. The characteristics of the spinning glands of Polenecia are compared with those of other uloborids. Present knowledge of the spinning apparatus of uloborids leads to a renewed discussion of the origin of the orb web in this family and in araneids. It is concluded that these two types of orb webs emerged from independent evolutionary processes.     

A cell culture model of chemically and spontaneously derived mouse lung alveologenic carcinoma

Malignant cell lines related to mouse lung alveologenic carcinoma have been established from urethane-induced tumors and after in vitro spontaneous transformation of preneoplastic cell lines. Both the chemically and spontaneously transformed cell lines formed invasive, poorly differentiated carcinomas with secondary lung deposits when implanted subcutaneously in immune-suppressed mice. They differed from the related preneoplastic cell line in coordinately exhibiting anchorage-independent growth, reduced epidermal growth factor receptor activity and absence of pericellular fibronectin. These data suggest that similar molecular events may occur in type 2 pneumocyte-related cells in order to generate mouse lung alveologenic adenomas and carcinomas by both spontaneous and chemical carcinogen induction mechanisms. A reduced level of pericellular fibronectin was also demonstrated in an in situ compressive urethane-induced mouse lung adenoma. Loss of pericellular fibronectin may therefore be an early and persistent phenotypic alteration during transformation to the alveologenic adenoma and carcinoma.Abbreviations EGF epidermal growth factor - TGF transforming growth factor     

Comparison of the structure of HLA-Bw47 to HLA-B13 and its relationship to 21-hydroxylase deficiency

Adrenal 21-hydroxylase deficiency is strongly associated with HLA-Bw47. This rare HLA allele and the HLA-B13 allele are both found in positive genetic linkage disequilibrium with HLA-A3, -Cw6, -DR7 and also display serological cross-reactivity. To investigate the relationship between these two alleles at the structural level, the nucleotide sequences of the HLA-B13 and HLA-Bw47 genes have been determined. They differ by 28 nucleotides, resulting in 14 amino acid substitutions: 5 in the 1 domain, 8 in the 2 domain, and 1 in the transmembrane region. Comparison of HLA-Bw47 nucleotide sequence with other HLA-B sequences shows a segment of 228 by identical with B44 in the a 1 domain and a segment of 218 by identical with B27 in the a2 domain, but only a 91 by segment of identity with B13 in the al domain. The complex pattern of substitutions and their degree of divergence indicate that HLA-B13 and HLA-Bw47 alleles are not related by a simple mutational event.     

Filter Paper Dot-Immunobinding Assay for Detection of Spiroplasma citri

A rapid filter paper dot-immunobinding assay was adapted to detect the wall-less mollicute Spiroplasma citri in medium, plants, or insects. Filter paper spotted with sample was incubated first in dilute antiserum, then in protein A-peroxidase, and finally in a substrate of 4-chloro-1-naphthol plus hydrogen peroxide. The detection limit averaged 2.3 × 10¹⁰ CFU/ml in cultures, and S. citri was detected in single infected leafhoppers. This assay was less sensitive but more rapid and economical than an enzyme-linked immunosorbent assay.     

Behavior of fish predators and their prey: habitat choice between open water and dense vegetation

Synopsis Behavior of largemouth bass, Micropterus salmoides, and northern pike, Esox lucius, foraging on fathead minnows, Pimephales promelas, or bluegills, Lepomis macrochirus, was quantified in pools with 50% cover (half the pool had artificial stems at a density of 1000 stems m⁻²). Both predators spent most of their time in the vegetation. Largemouth bass searched for bluegills and ambushed minnows, whereas the relatively immobile northern pike ambushed all prey. Minnows were closer to predators and were captured more frequently than bluegills. Even when minnows dispersed, they moved continually and eventually wandered within striking distance of a predator. Bluegills dispersed in the cover with predators. Bass captured the few bluegills that strayed into the open and pike captured those that approached too closely in the cover. The ability of predators to capture prey while residing in habitats containing patches of dense cover may explain their residence in areas often considered to be poor ones for foraging. The unit is sponsored jointly by the United States Fish and Wildlife Service, Ohio Department of NaturalResources, The Ohio State University, and the Wildlife Management Institute     

Ontogeny and phylogeny of the trunk lateral line system in cichlid fishes

An examination of the ontogeny of the lateral line trunk canal and the diversity of adult trunk canal patterns among cichlids indicates that bidirectional canal formation is a general ontogenetic pattern in the Cichlidae with the exception of Cichla and those few species with a complete trunk canal pattern. In addition to the tubed scales which make up the trunk canal, some lateral line scales have pits containing superficial neuromasts. These are recognized as components of the lateral line system of the trunk in adult cichlids for the first time. Eight trunk canal patterns that are variations on a simple disjunct pattern are defined among the 17 cichlid genera examined. Using bidirectional canal formation as a developmental model, these patterns can be placed along an ontogenetic spectrum. This suggests that heterochrony (alterations in the timing of development) is an important mechanism of evolutionary change in the lateral line system of the trunk in cichlid fishes.     

Changes in germination and respiratory potential of embryos of dormant Grand Rapids lettuce seeds during long-term imbibed storage,and related changes in the endosperm

Grand Rapids lettuce (Lactuca sativa L.) seeds were stored in an imbibed state for up to two years. Embryos dissected from stored seeds showed a progressive loss with time in their ability to germinate on polyethylene glycol (PEG) solutions. Little germination of dissected embryos from one-month imbibed seeds occurred on-6 bar PEG but only after four months of storage did the dissected embryos fail to germinate on-4 bar PEG. After two years storage 30% of dissected embryos still were able to germinate on-2 bar PEG. This loss of germination potential, which may be a symptom of the development of an embryo dormancy, could be reversed by N⁶-benzyladenine (BA) and red light (R) applied together or separately to dissected embryos. Two weeks of chilling of 12-month imbibed seeds restored sensitivity to R and a 48-h BA pretreatment prior to R resulted in germination rates similar to those of seeds emerging from primary dormancy. There was loss of embryo control of endo--mannanase activity after two weeks of storage even though the endosperms themselves retained their capacity for enzyme synthesis for six more weeks. Eventually, then, endo--mannanase synthesis is not possible because of inherent changes in both the embryo and endosperm, although each tissue undergoes changes at its own rate. Oxygen uptake by embryos dissected from two-month imbibed seeds did not increase to the same extent as embryos dissected from freshly imbibed seeds. In intact seeds germinating from a skotodormant state, oxygen uptake increased at a time coincident with radicle protrusion, but did not achieve the levels of uptake of those seeds germinating from a primary dormant state. The decline in uptake of oxygen by secondary dormant seeds is the result of a lowered respiratory capability of the embryo itself, rather than of changes in permeability of the surrounding structures.Abbreviations BA N⁶-benzyladenine - Pfr active (far-redabsorbing) form of phytochrome - R red light - PEG polyethylene glycol     

Comparaison des teneurs en saccharose et en nucléotides riches en énergie des graines en germination d'une betterave sucrière et d'une betterave fourragère

Comparison of a sugar beet with a forage beet variety shows that, during germination, the seedlings have the same nucleoside triphosphate content, but those of sugar beet contain more sucrose and less UDPG than those of forage beet.