Histamine-like immunoreactivity in photoreceptors of the compound eyes and ocelli of the flies Calliphora erythrocephala and Musca domestica

Summary Antibodies to histamine were used for immunocytochemical studies of the visual system in the flies Calliphora erythrocephala and Musca domestica. Specific immunolabeling of photoreceptors was found both in the compound eyes and ocelli of both species. In the compound eyes histamine-like immunoreactivity (HA-IR) was found in all the short visual fibers (photoreceptors R1–6) and one type of long visual fiber (photoreceptor R8). In addition, the ocellar photoreceptors also show HA-IR. In view of earlier biochemical and pharmacological/physiological findings by Elias and Evans (1983) and Hardie (1987) it thus seems likely that histamine is a neurotransmitter in insect photoreceptors. Interestingly, the second type of long visual fiber (photoreceptor R7) has recently been found to be GABA-immunoreactive (Datum et al. 1986). The two types of long visual fibers may hence use different transmitters which act on different receptors of the postsynaptic neurons in the second visual neuropil, the medulla. In addition to the photoreceptors in the retina and ocelli, we found processes of HA-IR neurons in one of the optic lobe neuropils, the lobula. This finding indicates that histamine may also be a transmitter in certain interneurons in the visual system.Abbreviations HA histamine - GABA -amino butyric acid - GAD glutamic acid decarboxylase - 5-HT 5-hydroxytryptamine (serotonin) - HA-IR histamine-like immunoreactivity - R1-R6 class of short-axoned photoreceptors - R7 and R8 long-axoned photoreceptors - LMC large monopolar neuron of lamina - HSA human serum albumin - PBS phosphate-buffered saline - DEPC diethylpyrocarbonate     

Light- and electron-microscopic immunocytochemistry of peptidergic neurons innervating thoracico-abdominal neurohaemal areas in the blowfly

Summary Ventral thoracic neurosecretory cells (VTNCs) of the blowflies, Calliphora erythrocephala and C. vomitoria, innervating thoracic neuropil and the dorsal neural sheath of the thoracico-abdominal ganglion have been shown to be immunoreactive to a variety of mammalian peptide antisera. In the neural sheath the VTNC terminals form an extensive neurohaemal network that is especially dense over the abdominal ganglia. The same areas are invaded by separate, ut overlapping serotonin-immunoreactive (5-HT-IR) projections derived from neuronal cell bodies in the suboesophageal ganglion. Immunocytochemical studies with different antisera, applied to adjacent sections at the lightmicroscopic level, combined with extensive cross-absorption tests, suggest that the perikarya of the VTNCs contain co-localized peptides related to gastrin/cholecystokinin (CCK), bovine pancreatic polypeptide (PP), Met- and Leuenkephalin and Met-enk-Arg⁶-Phe⁷ (Met-enk-RF). Electron-microscopic immunogold-labeling shows that some of the terminals in the dorsal sheath react with several of the individual peptide antisera, whilst others with similar cytology are non-immunoreactive. In the same region, separate terminals with different cytological characteristics contain 5-HT-IR. Both 5-HT-IR and peptidergic terminals are localized outside the cellular perineurium beneath the acellular permeable sheath adjacent to the haemocoel. Hence, we propose that various bioactive substances may be released from thoracic neurosecretory neurons into the circulating haemolymph to act on peripheral targets. The same neurons may also interact by synaptic or modulatory action in the CNS in different neuropil regions of the thoracic ganglion.     

Host genetics: a key factor in regulating the distribution of parasites in natural host populations

The immune response that expels the tapeworm Hymenolepis citelli from the small intestine of its host the white-footed deer mouse is genetically controlled. Patent infections with this tapeworm occur only in individuals that are homozygous for a recessive allele expressed at a single gene locus. By studying this natural host-parasite system in the laboratory it was shown that host genetics contributes to parasite overdispersion in a host population in the absence of all other ecological variables. Thus, the substantive influence of the proportions of resistant and susceptible genotypes in the host population must be considered when developing parasite population models of transmission or control measures.     

Chemical composition of whole plant and grain and yield of nutrients in grain of five barley cultivars

Summary twenty seven field experiments were conducted to determine if there were differences between five barley cultivars in their ability to utilize soil nutrients. There were significant differences among cultivars in yield of grain and in concentration of all macro and micro nutrients examined in both the whole plant and grain.Gateway ranked the highest for the concentration of Na, Mn, and Cu in the whole plant and was among the cultivars with highest concentration of Ca, Fe, and Zn. Centennial had generally the lowest concentration of all the nutrients determined in the whole plant. For the concentrations of Na, Mg, and Cu in grain Gateway ranked highest, but ranked third for the concentrations of K, Ca, Fe, Mn, and Zn in grain. Galt had the highest K and Mg concentration and lowest Mn, Cu and Zn concentration in grain. Except for K concentration in grain, Centennial had the lowest concentrations of all other cationic nutrients in grain.Yield of grain rather than nutrient concentration was the most important criteria in determining the ranking of nutrient yields per hectare. Because of its high grain yield, Bonanza produced the largest yield of micronutrient cations and was second to Galt in production of macronutrient cations, although it was lowest in macronutrient cation concentration. Similarly, Bonanza and Galt had the lowest protein concentration, but produced the highest yield of protein per hectare.The implications for animal nutrition of different levels of nutrients between cultivars are discussed.     

Vegetation succession on the dunes near Oostvoorne,The Netherlands,since 1934, interpreted from air photographs and vegetation maps

The vegetation succession on the dunes near Oostvoorne, The Netherlands has been followed by means of a novel combination of repeated large-scale vegetation mapping and air photograph interpretation. Vegetation units have been discerned on the formation level because these could be distinguished fairly easily on the photographs and because the rates of change are appropriate to the time interval chosen. Nineteen formations were distinguished. Five 1:6250 maps were constructed, reflecting the formation pattern in 1934, 1943, 1959, 1972 and 1980. An overlay with 2736 grid points at 25 m field distance was used to quantify changes in the formation pattern.The results suggest a pronounced multiple pathway succession with nevertheless three principal trajectories of succession from pioneer to woodland vegetation. The outer dunes, which have originated since 1910, are distinct in successional characteristics from the inner dunes, which already existed but were released from heavy grazing pressure in 1910. The rate of change in the outer dunes was high in the beginning and is slowly decreasing eversince. In the inner dunes it went the other way around. Through visual extrapolation the likely formation patterns in 1910 and in 2000 were estimated.Transition frequencies proved highly variable for most formations. Moreover, strong spatial dependence was found. Limitations in the use of Markov models in cases of long-term succession in heterogeneous environments are discussed.Nomenclature follows the same sources as in van der Maarel et al. (1984).Field work carried out 1980–1981 when the authors were at the Division of Geobotany, University of Nijmegen. We thank Jos Rijntjes, Nijmegen, for his cooperation in the field. Vegetation maps were prepared and calculations performed at Uppsala. We thank the Foundation Het Zuid-Hollands Landschap, Rotterdam, for providing facilities and a grant for fieldwork as well as additional means to reproduce the vegetation maps. Two reviewers gave useful comments.     

Differential effects of positive and negative proliferative stimuli on murine cytolytic and helper T-cell clones

Studies were performed to determine whether substances could be identified which exhibited differential regulatory effects--either positive or negative--on the growth of murine alloreactive cytolytic (Tc) and helper (Th) cloned T-cell lines. The following lines of evidence suggested that Tc and Th proliferate in response to the same growth factor (GF). (1) When GF-containing fluids from cultures of phorbol myristic acetate (PMA)-activated EL4 thymoma were fractionated by a variety of biochemical techniques. Tc and Th eluted together. (2) Absorption of GF-containing supernatants with either cloned Tc or cloned Th depleted GF activity for each to a similar extent, and GF eluted from either Tc or Th to which it had adsorbed supported the proliferation of Tc and Th equally well. (3) Lectin-depleted supernatants from cultures of concanavalin A (Con A)-activated Th stimulated the proliferation of Th as well as Tc. (4) Recombinant human interleukin (IL-2) supported the growth of Tc and Th with equal efficiency. On the other hand, the following observations indicated that Tc and Th differed in their responses to inhibitors of GF-driven proliferation. (1) Con A at greater than or equal to 0.3 micrograms/ml inhibited the GF-driven proliferation of each of three Th lines but not either of two Tc lines. To the contrary, Con A enhanced GF-dependent proliferation of Tc. (2) Like Con A, allogeneic splenocytes selectively depressed GF-driven proliferation of Th but not Tc. (3) A substance generated during the acid elution of GF from cells, possibly a modified fetal calf serum component, greatly reduced the GF-driven proliferation of Tc but not Th. These results suggest that differential control of the proliferation of Tc and Th in cellular immune responses may be achieved via negative regulatory signals and raise the possibility that substances which can selectively depress the proliferation of specific T-cell subsets might be found which would be of therapeutic value.     

Clinical and immunological evaluation of 20 patients with advanced colorectal cancer treated with high dose recombinant leukocyte interferon-αA (rIFNαA)

Summary A total of 20 patients with advanced colorectal cancer received recombinant leukocyte interferon-A (rIFNA) either chronically (group I: twice a week up to 20×10⁶ IU/m² i.m.) or cyclically (group II: 1–4 periods of 8 consecutive days up to 20×10⁶ IU/m² i.m. daily at 20-days intervals) over a period of 12 weeks. There was 1 partial response, 1 mixed response and 1 patient with stable disease, whilst 17 patients had progressive disease. Median survival was 15.5 months. Survival was significantly shorter when the extent of hepatic disease was >25% (P=0.05), extrahepatic disease was extensive (P<0.005), alkaline phosphatase level was >2× normal (P<0.02), or performance status was <100% (P<0.001). Toxicity consisting mainly of fever, fatigue, anorexia and weight loss was serious in group I and minimal in group II. Administration of rIFNA led to a short lived augmentation of natural killer (NK) cell activity. In the cyclically treated group this was a recurrent phenomenon whereas a marked lasting depression of NK cell activity was seen in chronically treated patients. Interferon- production capacity was significantly stimulated during rIFNA therapy. The differences in toxicity and immunostimulatory effects between the two schedules may be of importance in the design of further studies.This trial was supported in part by Hoffmann-La Roche, Basle     

Serotonin-like immunoreactivity in the optic lobes of three insect species

The cellular localization of 5-HT in the optic lobes of three insect species was assayed with the use of antibodies raised against 5-HT. In Schistocerca, Periplaneta, and Calliphora all neuropil regions of the optic lobe, the lamina, medulla and lobula, contain 5-HT-immunoreactive varicose fibres in different patterns, like columns and layers. Such fibres also connect the lobula to neuropil in the lateral protocerebrum. In Calliphora also 5-HT-positive fibres of the medulla and lobula plate have projections to the lateral protocerebrum, whereas the origin of the lamina fibres is not certain. In all species the processes displaying 5-HT-like immunoreactivity appear to be derived from a relatively small number of cell bodies, each neuron thus having processes over a large volume of the neuropil of the optic lobe in different layers.     

Clinical Trial of Lincomycin Hydrochloride in Reiter's Disease

A double-blind trial comparing lincomycin hydrochloride (Mycivin) and placebo in 22 patients with Reiter''s disease showed no significant difference in clinical or laboratory findings between the two groups. It is concluded that lincomycin hydrochloride is no more effective than placebo in the treatment of Reiter''s disease.