Neuroendocrine organs of the lemon-butterfly, Papilio demoleus L. II. The corpora cardiaca-allata complex of the adult.

The retrocerebral endocrine organs of the adult lemon-butterfly; Papilio demoleus have been described. The organs are subaortic lying closely behind the brain. While the nervi corporis cardiaci I (NCCI) originate from the protocerebrum of the brain, the NCCII seem to take their origin in the tritocerebrum in common with another nerve named earlier as the tegumentary nerve. The corpora cardiaca (CC) and corpora allata (CA) are closely approximated to each other obliterating the nervi corporis allati (NCA) which are conspicuous in the larva of the same species. An intercardiacal bridge (ICB) connects the CC of the two sides and acts as a possible centre of distribution for the neurosecretory material (NSM) to the gut. Histological evidence suggests that the NSM inside the CC remains intraaxonal without being primarily unloaded in the organs for storage. The intrinsic secretory cell of the CC are intimately associated with the neurosecretory fibres from the brain and bear fairly thick axons. No NSM could be detected in the CA of this insect.     

Studies on the neuroendocrine system of the mangohopper, Idiocerus atkinsoni Leth. (Homoptera : Jassidae)

The neuroendocrine system of the homopteran, Idiocerus atkinsoni has been described, employing a neurosecretory stain. Two groups of medial neurosecretory cells (NSC) of one tinctorial type are present in the pars intercerebralis of the brain. Processes believed to be dendrites of the neurosecretory neurons lie superficially underneath the neurilemma and enclose neurosecretory material (NSM). Both the nervi corporis cardiaci, NCCI and NCCII, are branched. The branches of the former join to form an oesophageal nerve that runs on the oesophageal surface and terminates on the midgut, and those of the latter, innervate the oesophageal dilator muscles. Besides being present in the dendrite-like processes and NSC, the NSM is also seen in the NCCI, anterior part of the aorta and oesophageal nerve but not in the NCCII, corpora cardiaca (CC) and the corpus allatum (CA). It is suggested that the release of NSM into the circulation in this insect occurs through two main routes: the dendrites and the aorta. The evolution of the aorta as an exclusive neurohaemal organ in Hemiptera is discussed.     

Changes induced by formalin in the hypothalamic neurosecretory system of the spotted owlet, Athene brama temminck.

Histological changes induced in the HNS of the spotted owlet, Athene brama Temminck, by injection of 1 ml 5 or 10% formalin are described. No difference could be detected in the response of the HNS to 5 or 10% formalin administration. In the HNS of birds killed within 5 min of formalin administration, there was only partial depletion of NSM from the neurons, the tract and the NL; the quantity of NSM in the AME remained more or less unchanged. In animals killed 10-90 min after formalin injection, the depletion of NSM from the neurons, the tract and the NL was more complete. The neurons of the preoptic division of the SON exhibited the maximum response; these neurons were also moderately hypertrophied. The NL also was hypertrophied in some animals; the NSM in the AME registered only a partial loss. The interval between formalin administration and killing did not influence the degree of changes in the HNS. The depletion of NSM was no greater at 90 min following formalin injection than at 10 min. Since it is well established that formalin stress causes augmented secretion of ADH and that there is a close functional relationship existing between ADH and NSM, the depletion of NSM noticed in the HNS of the spotted owlet following formalin administration is interpreted as indicating augmented secretion of ADH. Hence it seems that the response of the HNS of birds to formalin stress are comparable to those of the HNS of mammals. The results thus provide histological evidence in favour of the concept that stressful stimuli cause increased secretion of ADH.     

Effect of azadirachtin A on neuroendocrine activity in Locusta migratoria

Summary The neurosecretory activity of azadirachtin A-treated Locusta migratoria that failed to mature was compared with that of rapidly maturing control females by means of histological techniques. High resolution drymount autoradiography was used to localize [22,23-³H₂]dihydroazadirachtin A in the brain and corpus cardiacum (CC). The neurosecretory system of the locusts treated with this insecticide was accompanied by an unusually high accumulation of paraldehyde fuchsin (PAF)-stainable neurosecretory material (NSM) in the brain fibers and in the storage lobes of the CC. The control females never had such an intense accumulation of NSM. The accumulation of NSM, resulting from its poor release, may influence its synthesis which is controlled by feed-back regulation. [22,23-³H₂]Dihydroazadirachtin A is localized mainly at the peripheral blood-brain barrier and does not penetrate into the brain effectively, whereas it completely covers the CC. It is concluded that azadirachtin A affects the endocrine activity of the brain in an indirect way.     

Morphological and histological studies on the neuroendocrine system of the sugarcane leaf hopper, Pyrilla perpusilla Wlk. (Fulgoridae: Hemoptera)

Neuroendocrine system of the sugarcane leaf hopper, Pyrilla perpusilla, has been studied by employing PAVB and AF techniques in situ and on sections. There are four groups of NS cells in the brain, a medial of 14--17 cells, lateral and an antero-ventral of 2 cells each and a latero-ventral of a single cell. The cells are of A and B types: tinctorially the A-cells are further subdivided into A1, A2 and A3 subtypes. Suboesophageal and thoracic ganglions have 2 groups of 2 and 3 cells, each of A and B types. Axons of the cells of cerebral groups converge to form a common pathway which emerge from the protocerebrum as NCC. NSM transports both inter and intracellularly. In CC stained colloids accumulate at the commissuris, the gland has two--A and B--types of intrinsic cells. CA is devoid of NSM. Though considerably small in size and have new NS cells, its NS pathways are easily demonstrated in situ. It is emphasized that size and number of neurosecretory axons is not a limitation of the in situ technique but the demonstration of the tract depends upon the physiological state of the animal at the time of fixation.     

Studies on the neurosecretory system and retrocerebral endocrine glands of Nezara viridula Linn. (Heteroptera: Pentatomidae)

The neurosecretory system and retrocerebral endocrine glands of Nezara viridula Linn. have been described on the basis of in situ preparations and histological sections employing the paraldehyde fuchsin (PF) and performic acid-victoria blue (PAVB) techniques. In the brain of N. viridula, there are two medial groups–each consisting of five neurosecretory cells which belong to A-type. The lateral neurosecretory cells are absent. The axons of the two groups of medial neurosecretory cells (MNC) compose the two bundles of neurosecretory pathways (NSP) that decussate in the anterodorsal part of the protocerebrum. The two pathways, after the cross-over, run deep into the protocerebrum and deutocerebrum and emerge as NCC-I from the tritocerebrum. The nervi corporis cardiaci-I (NCC-I) of each side which are heavily loaded with NSM terminate in the aorta wall. Thus, the neurosecretory material (NSM), elaborated in the medial neurosecretory cells of the brain, is stored in the aortic wall and nervi corporis cardiaci-I (NCC-I). The NCC-II are very short nerves that originate from the tritocerebrum and terminate in the corpora cardiaca (CC) of their side. Below the aorta, but dorsal to the oesophagus, lie two oval or spherical corpora cardiaca. A corpus allatum (CA) lies posterior to the corpora cardiaca (CC). The corpora cardiaca do not contain NSM; only the intrinsic secretion of their cells has been occasionally observed which stains orange or green with PF staining method. The corpus allatum sometimes exhibits PF positive granules of cerebral origin. A new connection between the corpus allatum and aorta has been recorded. The suboesophageal ganglion contains two neurosecretory cells of A-type which, in structure and staining behaviour, are similar to the medial neurosecretory cells of the brain. The course and termination of axons of suboesophageal ganglion neurosecretory cells, and the storage organ for the secretion of these cells have been reported. It is suggested that the aortic wall and NCC-I axons function as neurohaemal organ for cerebral and suboesophageal secretions.     

Antigen-specific and nonspecific mediators of T cell/B cell cooperation. III. Characterization of the nonspecific mediator(s) from different sources.

T cell-containing lymphoid populations produce a nonantigen-specific mediator(s) (NSM) which can replace T cell helper function in vitro in the response of B cells to sheep red blood cells (SRBC), but not to the hapten-protein conjugate, trinitrophenyl-keyhole limpet hemocyanin, (TNP-KLH). NSM produced under three conditions: 1) stimulation of KLH-primed cells with KLH; 2) allogeneic stimulation of normal spleen cells; and 3) stimulation of normal spleen cells with Con A (but not PHA) are indistinguishable on the basis of their biologic activity and m.w., estimated as 30 to 40,000 daltons by G-200 chromatography. Production of NSM is dependent on the presence of T cells. The action of NSM on B cells responding to SRBC in the presence of 2-mercaptoethanol is unaffected by severe macrophage depletion. Extensive absorption of NSM with SRBC failed to remove its activity, confirming its nonantigen-specific nature.     

Two C. elegans genes control the programmed deaths of specific cells in the pharynx.

The genes ces-1 and ces-2 control the decisions of two cells in the nematode Caenorhabditis elegans to undergo programmed cell death. Mutations that cause a gain of ces-1 function or a reduction of ces-2 function prevent these cells, the sisters of the two pharyngeal NSM neurons, from dying. These mutations do not affect most other cell deaths. Genetic studies indicate that ces-1 and ces-2 affect the fates of the NSM sisters by regulating the genes required for all programmed cell deaths to occur.     

Transgenic tobacco plants expressing the putative movement protein of tomato spotted wilt tospovirus exhibit aberrations in growth and appearance

Within the Bunyaviridae virus family, members of the genus Tospovirus are unique in their ability to infect plants. A characteristic genetic difference between tospoviruses and the animal-infecting members of this virus family is the occurrence of an additional gene, denoted NSM, located on the genomic M RNA segment. This gene has previously been implicated in the cell-to-cell movement of this virus during systemic infection. Transgenic tobacco plants have been obtained expressing the NSM protein of tomato spotted wilt virus (TSWV), the type member of the tospoviruses, from a constitutive promoter. Detectable amounts of the NSM protein could be observed in plants from nine different lines. The protein was only detectable in fractions enriched for cell wall material. More detailed immunogold labelling studies revealed specific association of NSM protein with plasmodesmata. Plants accumulating the NSM protein to detectable levels developed aberrations in growth, resulting in a significant reduction of size and accelerated senescence. In addition, these plants are restricted in their capacity to produce flowers. The results presented provide additional evidence that the NSM protein, by modifying plasmodesmata, represents the cell-to-cell movement function of tospoviruses. Furthermore, the phenotype of the NSM transgenic plants suggests involvement of the NSM gene product in TSWV symptom expression     

Construction costs and physico-chemical properties of the assimilatory organs of Nepenthes species in Northern Borneo

BACKGROUND AND AIMS: Species of the Nepenthaceae family are under-represented in studies of leaf traits and the consequent view of mineral nutrition and limitation in carnivorous plants. This study is aimed to complement existing data on leaf traits of carnivorous plants. METHODS: Physico-chemical properties, including construction costs (CC), of the assimilatory organs (leaf and pitcher) of a guild of lowland Nepenthes species inhabiting heath and/or peat swamp forests of Brunei, Northern Borneo were determined. KEY RESULTS: Stoichiometry analyses indicate that Nepenthes species are nitrogen limited. Most traits vary appreciably across species, but greater variations exist between the assimilatory organs. Organ mass per unit area, dry matter tissue concentration (density), nitrogen (N), phosphorus (P), carbon, heat of combustion (H(c)) and CC values were higher in the leaf relative to the pitcher, while organ thickness, potassium (K) and ash showed the opposite trend. Cross-species correlations indicate that joint rather than individual consideration of the leaf and the pitcher give better predictive relationships between variables, signalling tight coupling and functional interdependence of the two assimilatory organs. Across species, mass-based CC did not vary with N or P, but increases significantly with tissue density, carbon and H(c), and decreases with K and ash contents. Area-based CC gave the same trends (though weaker in strength) in addition to a significant positive correlation with tissue mass per unit area. CONCLUSIONS: The lower CC value for the pitcher is in agreement with the concept of low marginal cost for carnivory relative to conventional autotrophy. The poor explanatory power of N, P or N : P ratio with CC suggests that factors other than production of expensive photosynthetic machinery (which calls for a high N input), including concentrations of lignin, wax/lipids or osmoregulatory ions like K(+), may give a better explanation of the CC variation across Nepenthes species.     

Identification of virus-coded nonstructural polypeptides in bunyavirus-infected cells.

Analyses of bunyavirus-infected cell extracts identified at least two virus-induced nonstructural polypeptides. With snowshoe hare (SSH), La Crosse (LAC), and six SSH-LAC reassortant viruses, it was shown that one of these nonstructural polypeptides (NSs, approximate molecular weight, 7.4 X 10(3)) is coded by the SSH small (S)-size viral RNA species. This nonstructural polypeptide was not detected (at least in the same relative abundancies) in LAC virus-infected cells or in cells infected with reassortants having LAC S RNA. For SSH virus, tryptic peptide analyses of either [3H]leucine- or [3H]arginine-labeled NSs indicated that it contains unique sequences not present in the SSH nucleocapsid (N) polypeptide (also coded by the S RNA; J. R. Gentsch and D. H. L. Bishop, J. Virol. 28:417-419, 1978). Analyses of SSH virus-infected cell extracts and extracts of cells infected with SSH-LAC reassortants having SSH medium (M)-size RNA species indicated that a nonstructural polypeptide (NSM; approximate molecular weight, 12 X 10(3)) is coded by the SSH M RNA species. In extracts of LAC virus-infected cells (or cells infected with SSH-LAC reassortants having LAC M RNA), a polypeptide with an electrophoretic mobility slightly faster than that of the SSH NSM polypeptide was observed (approximate molecular weight, 11 X 10(3)); it has been designated LAC NSM. The relationships of the NSM polypeptides to the other M RNA-coded polypeptides (G1 and G2; J. R. Gentsch and D. H. L. Bishop, J. Virol. 30;767-770, 1979) have not been determined. Two additional polypeptides present in both LAC- and SSH-infected cell extracts also appear to be virus induced (one with an approximate molecular weight of 10 X 10(3), p10; the other with an approximate molecular weight of 18 X 10(3), p18). Whether these polypeptides are virus coded has not been determined.     

LvNumb works synergistically with Notch signaling to specify non-skeletal mesoderm cells in the sea urchin embryo

Activation of the Notch signaling pathway segregates the non-skeletogenic mesoderm (NSM) from the endomesoderm during sea urchin embryo development. Subsequently, Notch signaling helps specify the four subpopulations of NSM, and influences endoderm specification. To gain further insight into how the Notch signaling pathway is regulated during these cell specification events, we identified a sea urchin homologue of Numb (LvNumb). Previous work in other model systems showed that Numb functions as a Notch signaling pathway antagonist, possibly by mediating the endocytosis of other key Notch interacting proteins. In this study, we show that the vegetal endomesoderm expresses lvnumb during the blastula and gastrula stages, and that the protein is localized to the presumptive NSM. Injections of lvnumb mRNA and antisense morpholinos demonstrate that LvNumb is necessary for the specification of mesodermal cell types, including pigment cells, blastocoelar cells and muscle cells. Functional analysis of the N-terminal PTB domain and the C-terminal PRR domain of LvNumb shows that the PTB domain, but not the PRR domain, is sufficient to recapitulate the demonstrable function of full-length LvNumb. Experiments show that LvNumb requires an active Notch signal to function during NSM specification and that LvNumb functions in the cells responding to Delta and not in the cells presenting the Delta ligand. Furthermore, injection of mRNA encoding the intracellular domain of Notch rescues the LvNumb morpholino phenotype, suggesting that the constitutive intracellular Notch signal overcomes, or bypasses, the absence of Numb during NSM specification.     

Cellular immunologic reactions in mice tolerant to the transplantation antigens after immunization with the cross-reacting microbial antigens]

In combined administration of cyclophosphamide and lymphocytes of mice (CC57BR XX C3H) F1 to mice CC57BR there was observed a tolerance to alloantigens of mice C3H. Immunization of the tolerant mice with the vaccines of streptococcus, group A, and Candida albicans, containing antigens similar to the transplantation ones, led, to the partial destruction of the tolerance. This was expressed in the reduction in the CC57BR mice of the survival of skin allotransplants of mice C3H and the appearance in the lymphoid organs of lymphocytes with the cytotoxic activity against the allogenic target cells. In case of the tolerance destruction the amount of the recipient's lymphocytes forming rosettes with the erythrocytes of mice C3H remained unchanged, but the stem cell count fell in the spleen and the lymph nodes. The total amount of the T- and B-lymphocytes in the lymphoid organs was unchanged in destruction of the tolerance.     

Impact of target site distribution for Type I restriction enzymes on the evolution of methicillin-resistant Staphylococcus aureus (MRSA) populations

A limited number of Methicillin-resistant Staphylococcus aureus (MRSA) clones are responsible for MRSA infections worldwide, and those of different lineages carry unique Type I restriction-modification (RM) variants. We have identified the specific DNA sequence targets for the dominant MRSA lineages CC1, CC5, CC8 and ST239. We experimentally demonstrate that this RM system is sufficient to block horizontal gene transfer between clinically important MRSA, confirming the bioinformatic evidence that each lineage is evolving independently. Target sites are distributed randomly in S. aureus genomes, except in a set of large conjugative plasmids encoding resistance genes that show evidence of spreading between two successful MRSA lineages. This analysis of the identification and distribution of target sites explains evolutionary patterns in a pathogenic bacterium. We show that a lack of specific target sites enables plasmids to evade the Type I RM system thereby contributing to the evolution of increasingly resistant community and hospital MRSA.     

A critical review of the use of Clara cell secretory protein (CC16) as a biomarker of acute or chronic pulmonary effects

Biomarkers associated with asthma aetiology and exacerbation have been sought to shed light on this multifactorial disease. One candidate is the serum concentration of the Clara cell secretory protein (CC16, sometimes referred to as CC10 or uteroglobin). In this review, we examine serum CC16's relation to asthma aetiology and exacerbation. There is evidence that acute exposures to certain pulmonary irritants can cause a transient increase in serum CC16 levels, and limited evidence also suggests that a transient increase in serum CC16 levels can be caused by a localized pulmonary inflammation. Research also indicates that a transient increase in serum CC16 is not associated with measurable pulmonary damage or impairment of pulmonary function. The biological interpretation of chronic changes in serum CC16 is less clear. Changes in serum CC16 concentrations (either transient or chronic) are not specific to any one agent, disease state, or aetiology. This lack of specificity limits the use of serum CC16 as a biomarker of specific exposures. To date, many of the critical issues that must be understood before serum CC16 levels can have an application as a biomarker of effect or exposure have not been adequately addressed.     

Neurosecretory system of the earwig Labedura riparia, and the rôle of the aorta as a neurohaemal organ

The neurosecretory system of Labedura riparia has been described from sections and whole mounts using a variety of techniques. The pars intercerebralis contains two clusters of medial neurosecretory cells (MNC), each cluster consisting of 8 to 10 A-cells and occasional B-cells. The lateral sides of the brain have a few B-cells. The axons of the median neurosecretory cells terminate in the cephalic aorta (AO), whereas the axons of the lateral neurosecretory cells (LNC) terminate in the corpora cardiaca (CC). It appears that the neurosecretory material (NSM) elaborated in the MNC is stored in the cephalic aorta and that elaborated in the LNC is stored in the corpora cardiaca, which are two oval or elongate bodies composed of large chromophobe and small chromophil cells. Posteriorly there is the oval or elongate corpus allatum (CA) attached to the CC by thick nerves. The CA consists of one cell type only. Both CC and CA contain no A-cell neurosecretory material. It has been suggested that the neurosecretory system of L. riparia is composed of two complexes. One is formed by the medial neurosecretory cells for which the aorta functions as a neurohaemal organ, and the other is formed by lateral neurosecretory cells-lateral neurosecretory pathways-nervi corporis cardiaci-II in which the corpora cardiaca function as a neurohaemal organ.     

A critical review of the use of Clara cell secretory protein (CC16) as a biomarker of acute or chronic pulmonary effects

Biomarkers associated with asthma aetiology and exacerbation have been sought to shed light on this multifactorial disease. One candidate is the serum concentration of the Clara cell secretory protein (CC16, sometimes referred to as CC10 or uteroglobin). In this review, we examine serum CC16's relation to asthma aetiology and exacerbation. There is evidence that acute exposures to certain pulmonary irritants can cause a transient increase in serum CC16 levels, and limited evidence also suggests that a transient increase in serum CC16 levels can be caused by a localized pulmonary inflammation. Research also indicates that a transient increase in serum CC16 is not associated with measurable pulmonary damage or impairment of pulmonary function. The biological interpretation of chronic changes in serum CC16 is less clear. Changes in serum CC16 concentrations (either transient or chronic) are not specific to any one agent, disease state, or aetiology. This lack of specificity limits the use of serum CC16 as a biomarker of specific exposures. To date, many of the critical issues that must be understood before serum CC16 levels can have an application as a biomarker of effect or exposure have not been adequately addressed.