Quantitative fluorescence microscopy on dynamic changes of plastid nucleoids during wheat development

Summary Dynamic change of plastid nucleoids (pt nucleoids) was followed by fluorescence microscopy after staining with 46-diamidino-2-phenyl indole (DAPI). The fluorescence image was quantified with a supersensitive photonic microscope system based on photon counting and image analysis. The results showed that small pt nucleoids located in the center of proplastids in the dry seed increased in size after imbibition and formed highly organized ring structures in the dark, which divided into ca. 10 pieces within 3 days. Corresponding to this morphological change, DNA content of a plastid multiplied 7.5 fold. Total increase in DNA content of pt nucleoids per cell was 34 times as that of dry seed, as plastid multiplied 4.6 times in the average during this period. Upon light illumination small pt nucleoids having basic genome size were separated from divided pt nucleoids, suggesting a relationship with the formation of thylakoid system. The significance of the procedure established in this study is discussed in analysing the dynamic changes of intracellular small genomes.On leave from Department of Biology, Faculty of Science, Nagoya University, Furocho, Chikusaku, Nagoya 464, Japan.     

Genetics of yellow berry in wheat (Triticum aestivum)

Summary The inheritance of yellow berry, a grain disorder in durum and bread wheats, was studied in six intervarietal crosses in bread wheat. The trait was found to be controlled by either two or three dominant genes. Monosomic analysis using Chinese Spring monosomic series showed the presence of two major dominant genes on chromosomes 1A and 7A, and four modifiers on 4A, 4B, 6A and 6D, which influence the expression of yellow berry in bread wheat.     

Effects of in vivo ultrasound hyperthermia on natural killer cell cytotoxicity in the hamster

The effects of in vivo ultrasound irradiation of the spleen on immunological functions were assessed with an in vitro natural killer (NK) cell cytotoxic assay. Anesthetized hamsters were exposed to 1 MHz ultrasound at intensity levels currently being used clinically for therapeutic diathermy and hyperthermia (1-5 W/cm2, for 500 sec with constant beam scanning). Hyperthermic levels in the spleen ranged from 38-43 degrees C. Significant depression of natural killer (NK) cell activity was seen 4 h after spleen irradiation as compared to sham irradiated and normal animals. A return towards normal levels was observed in experimental groups at 24 h after exposure. Sham and normal animals were not significantly different in NK activity, indicating no significant stress-related immunosuppressive effects due to handling. Differential leukocyte counts taken for each exposure condition showed significant lymphopenia at 4, 8, and 16 h after exposure, near normal levels at 24 h, and complete recovery by 48 h. The number of circulating mononuclear cells at 4 h showed a dose-related suppression as the exposure intensities were increased.     

Ontogeny of human fetal catalase superoxide dismutase and lipid peroxidation: A comparative study

A comparative study on the activity profile of catalase and superoxide dismutase, the two scavenging enzymes, as well as the developmental profile of lipid peroxidation in the human fetal brain, liver and kidney have been done for gestation periods ranging from 12 weeks to 28 weeks and beyond. The activity of the scavenging enzymes increase gradually in_all the tissues with the advancement of pregnancy. Brain is an exception in case of catalase where the activity remains more or less same throughout the developmental period except in the case of fetuses, 28 weeks and above where significant decrease in the catalase activity is observed. A high level of lipid peroxidation is observed during early stages of development which declines thereafter.     

Organization of the nervous system of physonectid siphonophores

Summary An antiserum to the sequence Arg-Phe-amide (RFamide) was used to stain the nervous systems of various physonectid siphonophores. In the stem of Nanomia bijuga, this antiserum stained an ectodermal nerve net, which was interrupted, at regular intervals, by transverse collars of neurons. Injection of Lucifer yellow into the giant axon of the stem showed that this axon was dye-coupled to an ectodermal nerve net that resembled the RFamide-positive network. Ectodermal nets of neurons were also found in the pneumatophore, gastrozooids, tentacles and tentilla. At the junctions of the pneumatophore, the gastrozooids, the dactylozooids and the gonozooids with the stem, and at the junctions of tentacles and tentilla, collars or rings of neurons occurred. The stem was connected to the phyllozooids and nectophores by muscular lamellae, which were bordered by chains of neurons. At the margin of the nectophores, an immunoreactive nerve ring was found. Connected to this ring and located in theseitliche Zapfen (sidely-located patche), were two agglomerations of nerve cells. On the upper side of the bell margin, positioned at 90° relative to the seitliche Zapfen, a delta-shaped neuronal structure was found. This structure was connected to the nerve ring and was associated with a muscle, which ran a short distance along the exumbrellar surface.The nervous systems of Agalma elegans, Forskalia edwardsi, Forskalia leuckarti and Halistemma rubrum resembled that of Nanomia bijuga in all major respects.     

Localization of substance P-like immunoreactive fibers in the thoracic spinal cord of guinea pig

Summary A dorsal-horn fiber system is revealed in the thoracic spinal cord of guinea pig by means of substance P immunocytochemistry. This system has repeated craniocaudal and/or caudo-cranial extensions and possesses five main components: (1) a superficial network, situated beneath the dorsolateral surface of the spinal cord. This network is connected with the dorsal root fibers and the accumulations of substance P-like immunoreactive (SP-LI) fibers in the Lissauer's tract; (2) an accumulation of SP-LI fibers in the Lissauer's tract at the border of the dorsal horn; (3) two collateral SP-LI fascicles (one lateral and one medial) emerging from the SP-LI fiber accumulation in the Lissauer's tract; (4) a transversal fascicle running through laminae III–V, and (5) an SP-LI network in the region of the lateral spinal cord nucleus. These components of the dorsal-horn fiber system show widespread connections with ipsi-and contralateral spinal cord areas, connecting them in cranio-caudal and/or caudo-cranial directions. The SP-LI dorsal-horn system has close relationship with groups of preganglionic sympathetic cells in the intermediate zone of the spinal cord, respective with the vegetative network of this zone. It is suggested that some fibers of the dorsal-horn system that originate from dorsal-root ganglia may represent primary sensory or visceral afferents. It is likely that the dorsal-horn fiber system and the vegetative network of the thoracic spinal cord may represent the morphological basis for the integration of (1) the central and peripheral vegetative nervous systems, and (2) the somatic and vegetative nervous system.     

Localisation of substance P-, somatostatin-, vasoactive intestinal polypeptide and met-enkephalin-immunoreactive nerves in the peripheral and central nervous systems of the leech (Hirudo medicinalis)

Summary The distribution of substance P (SP)-, somatostatin (SOM)-, vasoactive intestinal polypeptide (VIP)- and met-enkephalin (mENK)-immunoreactive nerve fibres and cell bodies has been studied in the gastrointestinal tract, lateral blood vessel (heart) and segmental ganglia of the leech (Hirudo medicinalis). In the crop and intestine, there was a sparse distribution of VIP-, SP-, SOM- and mENK-immunoreactive nerves, while in the intestine, a dense network of SP-, a moderate network of SOM-, and a sparse distribution of mENK- and VIP-immunoreactive nerve fibres was seen. SP-, SOM- and VIP-immunoreactive nerve cell bodies were found in all the gut regions studied, the greatest number being in the intestine. No mENK-containing cell bodies were seen in any region of the gastrointestinal tract. The heart contained a few SP-, SOM-, and VIP-immunoreactive nerve fibres, but no nerve cell bodies were found. Immunoreactive nerve cell bodies were also present in the segmentai ganglia. A typical midbody ganglion contained up to seven pairs of SP-containing neurones, four pairs of SOM-containing neurones, two pairs of VIP-containing neurones and one to three pairs of mENK-immunoreactive nerve cell bodies. The lateral pair of large SOM-immunoreactive nerve cell bodies is of similar size and correct position to the lateral N cells. One of the pairs of large SP-immunoreactive nerve cell bodies is probably identical to the Leydig cells. A tentative identification of other immunofluorescent nerve cells is attempted. Immunoreactive nerve fibres to all four peptides were distributed throughout the neuropil, those to SP being the most numerous.     

Sensory projections to the nucleus basalis prosencephali of the pigeon

Summary The afferent pathways to the nucleus basalis prosencephali of the pigeon were studied by use of the horseradish peroxidase (HRP) technique. It was confirmed that this nucleus receives a direct pathway from the nucleus sensorius principalis nervi trigemini and that, as in the starling, it receives a direct input from the nucleus lemnisci lateralis, pars ventralis, an auditory relay. Totally novel is the finding that the nucleus basalis prosencephali is the target of a direct pathway originating in the medullary nucleus vestibularis superior. All three pathways bypass the thalamus. From within the telencephalon the nucleus basalis prosencephali also receives fibres from the tuberculum olfactorium and the peri-ectostriatal belt, suggestive of olfactory and visual input. Marked cell bodies were also found in the neostriatum frontolaterale. It is assumed that these arose from HRP uptake by axons of the tractus fronto-archistriatalis that course through the nucleus basalis prosencephali to the anterodorsal archistriatum. Marked fibres and bouton-like formations were observed in the latter structure. The afferents to the nucleus basalis prosencephali are discussed in conjunction with the probable role of the nucleus as a sensorimotor coordinator of the pecking/feeding behaviour of the pigeon.     

Tracing of single fibers of the nervus terminalis in the goldfish brain

Summary Central projections of the nervus terminalis (n.t.) in the goldfish were investigated using cobalt- and horseradish peroxidase-tracing techniques. Single n.t. fibers were identified after unilateral application of cobalt chloride-lysine to the rostral olfactory bulb. The central course and branching patterns of individual n.t. fibers were studied in serial sections. Eight types of n.t. fibers are differentiated according to pathways and projection patterns. Projection areas of the n.t. include the contralateral olfactory bulb, the ipsilateral periventricular preoptic nucleus, both retinae, the caudal zone of the periventricular hypothalamus bilaterally, and the rostral optic tectum bilaterally. N.t. fibers cross to contralateral targets in the anterior commissure, the optic chiasma, the horizontal commissure, the posterior commissure, and possibly the habenular commissure. We propose criteria that differentiate central n.t. fibers from those of the classical secondary olfactory projections. Branching patterns of eight n.t. fiber types are described. Mesencephalic projections of the n.t. and of secondary olfactory fibers are compared and discussed with regard to prior reports on the olfactory system of teleosts. Further fiber types for which the association with the n.t. could not be established with certainty were traced to the torus longitudinalis, the torus semicircularis, and to the superior reticular nucleus on the ipsilateral side.     

Enterotoxin A production in Staphylococcus aureus: inhibition by glucose

In this study, we investigated the relationship between carbohydrate metabolism and repression of staphylococcus enterotoxin A (SEA) in Staphylococcus aureus 196E and a pleiotrophic mutant derived from strain 196E. The mutant, designated at strain 196E-MA, lacked a functional phosphoenolpyruvate phosphotransferase system (PTS). The mutant produced acid, under aerobic conditions, from only glucose and glycerol. The parent strain contained an active PTS, and aerobically produced acid from a large number of carbohydrates. Prior growth in glucose led to repression of SEA synthesis in the parent strain; addition to the casamino acids enterotoxin production medium (CAS) led to more severe repression of toxin synthesis. The repression was not related to pH decreases produced by glucose metabolism. When S. aureus 196E was grown in the absence of glucose, there was inhibition of toxin production as glucose level was increased in CAS. The inhibition was related to pH decrease and was unlike the repression observed with glucose-grown strain 196E. The inhibition of SEA synthesis in mutant strain 196E-MA was approximately the same in cells grown with or without glucose and was pH related. Repression of SEA synthesis similar to that seen with glucose-grown S. aureus 196E could not be demonstrated in the mutant. In addition, glucose-grown S. aureus 196E neither synthesized -galactosidase nor showed respiratory activity with certain tricarboxylic acid (TCA) cycle compounds. Glucose-grown strain 196E-MA, however, did not show supressed respiration of TCA cycle compounds; -galactosidase was not synthesized because the mutant lacked a functional PTS. Cyclic adenosine-3, 5-monophosphate did not reverse the repression by glucose of SEA or -galactosidase synthesis in glucose-grown S. aureus 196E. An active PTS appears to be necessary to demonstrate glucose (catabolite) repression in S. aureus.Abbreviations SEA staphylococcal enterotoxin A - SEB staphylococcal enterotoxin B - SEC staphylococcal enterotoxin C - PTS phosphoenolpyruvate phosphotransferase system - CAS casamino acids salts medium - TCA tricarboxylic acid cycle