Myosmine in different organs of tobacco plant

Myosmine was found to be present in different organs of tobacco plant by TLC. Myosmine is a natural minor alkaloid of tobacco plant; it is not a decomposition product nor a 'smoke' alkaloid.     

Natural cyclic degeneration by a sequence of programmed cell death modes in <Emphasis Type="Italic">Semibalanus balanoides</Emphasis> (Linnaeus, 1767) (Crustacea,Cirripedia Thoracica)

The male reproductive system of the barnacle Semibalanus balanoides (Linnaeus, 1767) is a perfect model system for investigating naturally occurring cyclic nonpathological degeneration and programmed cell death (PCD). Every year after copulation, the barnacle degenerates its gonads, eggs, spermatids and penis initiated by severe environmental constraints. This is apparently a useful strategy for saving energy. By careful ultrastructural and immunohistochemical analysis of the male reproductive organs, we identified autophagic cell death in the penis and spermatids, both morphologically on ultrathin sections as well as histochemically for the first time on semithin tissue sections with the new antibody against microtubule-associated protein 1 light chain 3 (LC3). Apoptosis in the testis and vesicula seminalis was determined based on the morphological characters on the apoptosis-specific antibody against the apoptosis inducing factor (AIF), and on positive TUNEL (terminal in situ nick end labeling) nuclei. Secondary necrosis in late degrading stages occurred in all tissues investigated, based on morphological characters and weak TUNEL staining. Moreover, the ultrastructural screening showed transient forms of cell death in the ductus ejaculatorius epithelium, the epidermis, and the longitudinal muscles of the penis. According to the immunohistochemical tests, the cyclic degeneration of the male reproductive system follows a sequence of programmed cell death modes from autophagic cell death via apoptosis to secondary necrosis.     

Differences in the isodesmin pattern between the electric organs of Electrophorus electricus L.

Desmin, the intermediate filament protein of muscle, is present in the electric organs of Electrophorus electricus L. as five isovariants, instead of the one to two isovariants found in muscle. We analyzed the isodesmin pattern in the three different electric organs using densitometry of Coomassie blue-stained bands in electrofocusing polyacrylamide gel electrophoresis. We were able to compare the relative amount of each of the five desmin isovariants in an isodesmin pattern characteristic of each electric organ. These patterns proved to be, in some cases, statistically different. Desmin in each electric organ could have slightly different functions in order to correlate with the organ-specific isovariant patterns.     

Morphological and physiological differences of the auditory system in three related bushcrickets (Orthoptera: Phaneropteridae, Poecilimon)

Abstract. The auditory system of three closely related bushcrickets was investigated with respect to morphological and physiological differences. The size of the acoustic vesicle in the prothorax cavity and the size of the acoustic spiracle were compared to differences in auditory tuning of the tympanic nerve and differences in the directionality. The results indicate that a small auditory vesicle and auditory spiracle provide reduced sensitivity in the high frequency range (above 10—15 kHz), but increase sensitivity at low frequencies (below 10 kHz). The directionality of the hearing system deteriorates at frequencies between 10 and 25 kHz in species with a small spiracle and trachea. The evolutionary implications of these differences of the auditory systems are discussed. They are considered to be influenced more by ecological factors than bioacoustical ones.     

Nitrogen redistribution during grain growth in wheat (Triticum aestivum L.)

The activity of a range of endo- and exopeptidase enzymes have been measured in the glumes, flag leaf and stem during the period of grain development in wheat. The enzymes show a sequential pattern of appearance with activity peaks occurring at a number of intervals from anthesis until just prior to the cessation of grain growth. Of the enzymes studied only the haemoglobin- and casein-degrading activity and alanylglycine-dipeptidase activity increased during the period of rapid protein loss, while aminopeptidase, carboxypeptidase and leucyltyrosine dipeptidase reached maximum activity prior to this period.     

Immunological importance of the second gut segment of carp. I. Uptake and processing of antigens by epithelial cells and macrophages

Uptake and transport of soluble (ferritin) and particulate ( Vibrio anguillarum ) antigen from intestinal lumen to mucosal macrophages was studied using immunocytochemical and electron-microscopical techniques. Both antigens were taken up by epithelial cells of the second gut segment, reached the supranuclear vacuoles and were finally transported to large intraepithelial macrophages. In contrast with particulate antigen, antigenic determinants of ferritin were demonstrated in the basal part of the epithelium and appeared to be released at the mucosal site.
After anal intubation many small macrophages penetrated the intestinal epithelium, took up antigen and after 24 h disappeared again from the intestinal mucosa. This feature was antigen independent and also occurred after anal PBS-intubation. The larger, less mobile macrophages stayed in the intestinal epithelium and finally exposed antigenic determinants (of both antigens) at their outer surface, suggesting an antigen-presenting function. Whether these large macrophages can induce a local or mucosal immune response and whether the smaller mobile macrophages are involved in a systemic response is discussed.     

Theophrastus on geophytes

NEGBI, M., 1989. Theophrastus on geophytes . The nature of the geophilous organs of the geophytes described by Theophrastus (371-287 B.C.) in Historia Planiarum and De Causis Planlarum is presented and discussed. Most of the geophytes and the hydrogeophytes mentioned in these books (excluding species of Allium , biennial vegetables, and a few others) are critically reviewed. Certain lost agricultural practices mentioned by Theophrastus are strengthened and made explicable by comparisons from Pliny's Natural History , and Hebrew literature of the first centuries A.D.: Mishnah and Talmud. Theophrastus's interest in plants is shown to be of a pure nature although most of his examples are cultivated or otherwise useful plants. The possible sources of his knowledge of Egyptian plants are discussed.     

From humoral fever to neuroimmunological control of fever

Fever is a part of the acute phase response to infection or systemic inflammation. It is thus a part of a complex physiological defence strategy against micro-organisms invading the body of the host, or against non-microbial agents recognized as foreign by mobile immune cells of the body. The fever is induced by inflammatory mediators (prostaglandins, cytokines) released by immune cells activated by contacts with foreign molecules (exogenous pyrogens). These fever-inducing mediators, produced by the host cells (endogenous pyrogens), were originally thought to be distributed by means of the bloodstream (similarly to hormones) to different tissues of the body. Although the details of their transport across the blood–brain-barrier have not been clarified, it has been assumed that they activate the local production of inflammatory mediators within the brain, inducing a change in the thermoregulatory set-range and resulting in fever (humoral theory of fever). This concept has apparently changed in the past few years. Evidence has recently been presented supporting the possibility of the transport of immune signals to the brain via vegetative and peripheral nerves. In this review an attempt is made to describe the events leading to a fever response accompanying the systemic inflammation against a background of microbiological, immunological and physiological data. The experimental evidence published during the last five years has been reviewed, and a new concept of neuroimmunological control of fever is presented. This concept suggests that the host immune defence is coordinated through an integration of the neural, immune, hemopoietic and endocrine systems. The brain seems to be informed of any damage or antigenic challenge in the periphery of the body by a sensory host-monitoring system, and this information is confirmed by immune signals delivered by the humoral transport. The combination of these signals would allow the brain to recognize the nature of the challenge, and to activate an appropriate defence strategy. Fever as a part of many successful defence strategies against infections may thus be beneficial.