Visualization of Fruit Odor by Photoluminescence

Photoluminescence with visible emission spectrum was observed and visualized at the surface of certain fruits. This photoluminescence is associated with vapors of natural organic volatiles (odorants) emitted from the fruit surface. The photoluminescence spectra of various fruits (apple, pear, kiwi, and strawberry) were measured in vivo using a number of fluorometric methods. Fruit aging was found to be accompanied by modification of the photoluminescence spectrum shape and a noticeable increase in the photoluminescence intensity. Laser photoluminescence microscopy in vapors of fruit extracts and artificial compounds was used to assess the contribution of various substances to natural odor emission of fruits. The results of this study show that fluorometry of odors is a promising method for studying fruits and other objects.     

Characterization of B lymphocyte lineage progenitor cells from mice with severe combined immune deficiency disease (SCID) made possible by long term culture

A single gene mutation results in near absence of B and T lymphocytes and their immediate progenitors in mice with severe combined immunodeficiency disease (SCID). However, long term culture conditions allowed rapid outgrowth of lymphocytes from SCID bone marrow suspensions, and this permitted their detailed analysis. The cells were judged to be committed to the B lymphocyte lineage on the basis of expression of the BP-1 antigen, as well as by the density and pattern of expression of other markers. Cultured SCID lymphocytes were indistinguishable from control BALB/c cells in terms of morphology, typing for 13 cell surface markers, and changes in cell surface antigen expression with time in culture. In contrast to cultures of normal cells, which always included IgM synthesizing cells, SCID lymphocytes rarely expressed mu heavy chains. Southern blot analysis demonstrated that at least the first Ig gene rearrangement step had occurred in most of the cultured cells. The patterns of JH gene rearrangements suggested that relatively limited population diversity existed in individual cultures of SCID and normal BALB/c marrow. In addition, there was evidence that abnormal Ig heavy chain gene rearrangements had taken place in lymphocytes from approximately 25% of the SCID cultures. These cells were distinguished by the absence of detectable JH gene segments. kappa light chain genes appeared to be unrearranged in SCID cultured lymphocytes. We conclude that the lymphopoietic microenvironments of SCID mice are probably normal, and the animals have infrequent progenitors of B cells. Aberrant or nonproductive IgH gene rearrangements may account for the absence of pre-B and B cells in SCID mice. This study demonstrates the usefulness of long term culture methodology for isolating rare subsets of non-transformed lymphoid cells from normal and genetically defective hemopoietic tissues.     

Changes in leaf,stem, and root anatomy of Chrysanthemum cv. Lillian Hoek following paclobutrazol application

Plants ofChrysanthemum cv. Lillian Hoek were treated with a paclobutrazol (PBZ) soil drench and histologically examined after 3 months. PBZ application resulted in thicker leaves, reduced stem diameter, and roots with an increased diameter and an unusual segmented appearance. Increased leaf thickness was partly due to an additional layer of palisade mesophyll, although individual palisade cells were shorter, of smaller diameter, and more tightly packed. Spongy mesophyll depth was also greater and the individual cells were more rounded and the volume of intercellular space was reduced. The narrower stems had an increased development of secondary xylem, but had a marked reduction in the number of sclerenchyma bundle caps. Increased root diameter was due to an increase in the number of rows and diameter of cortical cells. In PBZ-treated plants, root cortical cell length was 50–70% less than in untreated plants, and this reduction appeared to be associated with the segmentation of the roots. PBZ inhibited secondary vascular development in the roots. This study is similar to other relevant studies in recording thicker leaves and roots with PBZ application; however, many of the underlying anatomical changes described above have not been previously reported.     

Induction of periodic breathing during sleep causes upper airway obstruction in humans

To test the hypothesis that occlusive apneas result from sleep-induced periodic breathing in association with some degree of upper airway compromise, periodic breathing was induced during non-rapid-eye-movement (NREM) sleep by administering hypoxic gas mixtures with and without applied external inspiratory resistance (9 cmH2O X l-1 X s) in five normal male volunteers. In addition to standard polysomnography for sleep staging and respiratory pattern monitoring, esophageal pressure, tidal volume (VT), and airflow were measured via an esophageal catheter and pneumotachograph, respectively, with the latter attached to a tight-fitting face mask, allowing calculation of total pulmonary system resistance (Rp). During stage I/II NREM sleep minimal period breathing was evident in two of the subjects; however, in four subjects during hypoxia and/or relief from hypoxia, with and without added resistance, pronounced periodic breathing developed with waxing and waning of VT, sometimes with apneic phases. Resistive loading without hypoxia did not cause periodicity. At the nadir of periodic changes in VT, Rp was usually at its highest and there was a significant linear relationship between Rp and 1/VT, indicating the development of obstructive hypopneas. In one subject without added resistance and in the same subject and in another during resistive loading, upper airway obstruction at the nadir of the periodic fluctuations in VT was observed. We conclude that periodic breathing resulting in periodic diminution of upper airway muscle activity is associated with increased upper airway resistance that predisposes upper airways to collapse.     

Monoclonal antibody against a melanosomal protein in melanotic and amelanotic human melanoma cells

BALB/c mice were immunized with tyrosinase, partially purified in two stages from a human melanoma cell line. A hybridoma was obtained which produced monoclonal antibody (MoAb 1C11) reactive with 8/10 melanoma cell lines and 10/10 primary cultures of human melanocytes, neval cells, and melanomas. Immunoreactivity correlated to a certain extent with tyrosinase activity but not with melanin content. No crossreactivity was obtained with neuroblastoma, medulloblastoma, fibroblasts, keratinocytes, lymphoid cells, or murine melanomas. Purification of the antigen directly from cell lysates with a MoAb 1C11 CNBr-Sepharose affinity column gave a green-brown protein of 56 kDa with no detectable tyrosinase activity. This protein was therefore different from 60 kDa active tyrosinase, identified by enzyme activity and Western blotting with a MoAb derived previously (MoAb 5C12). Unlike 5C12, 1C11 reactivity was not destroyed by pretreatment of the antigen with periodate. Immunogold labelling showed that the 1C11-reactive antigen was associated with melanosomes, and there was close correlation between 5C12 and 1C11 reactivity in resistance to trypsin and in staining various melanocytic cell populations. MoAb 1C11 may therefore recognise a polypeptide epitope in a molecule closely linked to melanin biosynthesis.     

Quantal melatonin suppression by exposure to low intensity light in man

Plasma melatonin concentrations were examined following three relatively low intensities of artificial light. Six normal, healthy control subjects were all exposed to (a) 200 lux, (b) 400 lux and (c) 600 lux for a three hour duration from midnight to 0300 h. Blood was also collected on a control night where light intensity was less than 10 lux throughout. Significant suppression of melatonin was observed following light of 400 lux and 600 lux intensity when compared to the control night (p less than 0.05; Mann-Whitney U-test). 200 lux light did not produce a statistically significant melatonin suppression when compared with control samples. Each light intensity produced its own individual maximal melatonin suppression by one hour of exposure. Increased duration of exposure to the light had no further influence on melatonin plasma concentrations. These data confirm a dose response relationship between light and melatonin suppression, and indicate that there is no reciprocal relationship between the effects of light intensity and the duration of exposure on maximal melatonin suppression in man.     

Parallel processing of mechanosensory inputs from the locust ovipositor by intersegmental and local interneurones

The neural pathways underlying the processing of signals from locust (Schistocerca gregaria) ovipositor hairs by different classes of interneurones are investigated.Spikes in the sensory neurones from these hairs evoke chemically-mediated, unitary EPSPs with a short and constant latency in six identified non-giant projection interneurones with cell bodies in the terminal abdominal ganglion. Five of these interneurones receive direct inputs from the valves ipsilateral to their neuropilar branches, whereas the other receives direct inputs from valves on both sides. The sensory neurone from a single hair makes divergent connections with several interneurones and those from different hairs make convergent connections with a given interneurone. The amplitude of the EPSPs evoked depends on the position of a hair along the proximal-distal axis of the valve, with sensory neurones from more distal hairs generating larger amplitude EPSPs.Deflection of hairs also excites three of the four giant projection interneurones through polysynaptic pathways and some local interneurones in the terminal abdominal ganglion through monosynaptic connections. Branches of non-giant projection interneurones, local interneurones, but not those of the giant interneurones, overlap the axon terminals of the ovipositor hair afferents in the terminal abdominal ganglion.