Nitric oxide synthase mediates regulation of cell polarity and movement during <Emphasis Type="Italic">Drosophila melanogaster</Emphasis> morphogenesis

The effect of expression of the enzyme producing nitric oxide on Drosophila melanogaster morphogenesis was studied using ectopic expression of a truncated splice form of the enzyme that has a dominant negative effect on the full-length enzyme form. The suppressed enzyme expression was shown to affect the cell polarity and movement as well as the structural pattern of organs during Drosophila development. The effect of nitric oxide production on the intercellular distribution of significant factors of cell polarity, protein products of the Strabismus and Prospero genes, has been revealed.     

Consistent effects of a major QTL for thermal resistance in field-released Drosophila melanogaster

Molecular genetic markers can be used to identify quantitative trait loci (QTL) for thermal resistance and this has allowed characterization of a major QTL for knockdown resistance to high temperature in Drosophila melanogaster. The QTL showed trade-off associations with cold resistance under laboratory conditions. However, assays of thermal tolerance conducted in the laboratory may not necessarily reflect performance at varying temperatures in the field. Here we tested if lines with different genotypes in this QTL show different thermal performance under high and low temperatures in the field using a release recapture assay. We found that lines carrying the QTL genotype for high thermal tolerance were significantly better at locating resources in the field releases under hot temperatures while the QTL line carrying the contrasting genotype were superior at cold temperatures. Further, we studied copulatory success between the different QTL genotypes at different temperatures. We found higher copulatory success in males of the high tolerance QTL genotype under hot temperature conditions, while there was no difference in females at cold temperatures. The results allow relating components of field fitness at different environmental temperatures with genotypic variation in a QTL for thermal tolerance.     

Stink bug interaction with host plants during communication

In solitary plant-dwelling stink bug species, success depends crucially on efficient mate location and recognition, mediated by signals transmitted through the plant. All stink bugs investigated so far communicate with species and sex-specific narrow-band calling and courtship song signals produced by abdomen vibration. Calling songs of lower specificity are characterized by readily repeated units emitted with regular repetition rate from the same place on a plant, while courtship songs take place at shorter distances in the process of species and sex recognition, together with signals of other modalities. Signal spectra with about 100Hz fundamental frequency and harmonics below 1000Hz are tuned to the resonant properties of their green host plants. The majority of the identified leg vibratory receptor cells and the underlying ventral cord interneurons respond best in the frequency range below 500Hz. Green plants with low pass filtering properties transmit optimally signals with a dominant frequency around 100Hz and strongly attenuate vibrations above 600Hz. Accurate tuning of signal spectral properties with the plant's mechanical characteristics enables communication over several meter distances, with dispersive bending waves running through the plant's rod-like structures under standing wave conditions.     

The influence of storage temperature during machine perfusion on preservation quality of marginal donor livers

Background

Although non-heart-beating donors have the potential to increase the number of available organs, the livers are used very seldom because of the risk of primary non-function. There is evidence that machine perfusion is able to improve the preservation of marginal organs, and therefore we evaluated in our study the influence of the perfusate temperature during oxygenated machine perfusion on the graft quality.

Methods

Livers from male Wistar rats were harvested after 60-min warm ischemia induced by cardiac arrest. The portal vein was cannulated and the liver flushed with Lifor® (Lifeblood Medical, Inc.) organ preservation solution for oxygenated machine perfusion (MP) at 4, 12 or 21 °C. Other livers were flushed with HTK and stored at 4 °C by conventional cold storage (4 °C-CS). Furthermore two groups with either warm ischemic damage only or without any ischemic damage serve as control groups. After 6 h of either machine perfusion or cold storage all livers were normothermic reperfused with Krebs–Henseleit buffer, and functional as well as structural data were analyzed.

Results

Contrary to livers stored by static cold storage, machine perfused livers showed independently of the perfusate temperature a significantly decreased enzyme release of hepatic transaminases (ALT) during isolated reperfusion. Increasing the machine perfusion temperature to 21 °C resulted in a marked reduction of portal venous resistance and an increased bile production.

Conclusions

Oxygenated machine perfusion improves viability of livers after prolonged warm ischemic damage. Elevated perfusion temperature of 21 °C reconstitutes the hepatic functional capacity better than perfusion at 4 or 12 °C.     

Revision of the pseudo-orbweavers of the genus Fecenia Simon, 1887 (Araneae, Psechridae), with emphasis on their pre-epigyne

The present paper provides a taxonomic revision of the genus Fecenia with emphasis on the characteristics of the pre-epigynes which are integrated for the first time into an identification key. As a result, one species is revalidated, Fecenia protensa Thorell, 1891, stat. n., and two new junior synonyms for Fecenia protensa are recognised: Fecenia sumatrana Kulczyński, 1908, syn. n. and Fecenia nicobarensis (Tikader, 1977), syn. n. New records are reported: Fecenia ochracea (Doleschall, 1859)from Malaysian Borneo, Fecenia macilenta (Simon, 1885) from Sumatra, Indonesia, Fecenia protensa from Thailand and Malaysia, Fecenia travancoria Pocock, 1899 from Sri Lanka and Thailand, and Fecenia cylindrata Thorell, 1895 from Thailand and Laos. Additional information on the biology of Fecenia is provided and the validity of characters for identifying Fecenia species is discussed.     

Mass spectrometric investigation of the neuropeptide complement and release in the pericardial organs of the crab, Cancer borealis

The crustacean stomatogastric ganglion (STG) is modulated by both locally released neuroactive compounds and circulating hormones. This study presents mass spectrometric characterization of the complement of peptide hormones present in one of the major neurosecretory structures, the pericardial organs (POs), and the detection of neurohormones released from the POs. Direct peptide profiling of Cancer borealis PO tissues using matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) revealed many previously identified peptides, including proctolin, red pigment concentrating hormone (RPCH), crustacean cardioactive peptide (CCAP), several orcokinins, and SDRNFLRFamide. This technique also detected corazonin, a well-known insect hormone, in the POs for the first time. However, most mass spectral peaks did not correspond to previously known peptides. To characterize and identify these novel peptides, we performed MALDI postsource decay (PSD) and electrospray ionization (ESI) MS/MS de novo sequencing of peptides fractionated from PO extracts. We characterized a truncated form of previously identified TNRNFLRFamide, NRNFLRFamide. In addition, we sequenced five other novel peptides sharing a common C-terminus of RYamide from the PO tissue extracts. High K+ depolarization of isolated POs released many peptides present in this tissue, including several of the novel peptides sequenced in the current study.     

Microampullary organs of a freshwater eel-tailed catfish,Plotosus (tandanus) tandanus

Whole body studies of Plotosus tandanus revealed that ampullary pores occur over the entire body of the fish, but are in higher concentrations in the head region. These pores give rise to a short canal (50-60 microm) produced by columnar epithelial cells bound together by tight junctions and desmosomes. At the junction of the canal and the ampulla, cuboidal epithelial cells make up the wall. The ampulla consists of layers of collagen fibers that surround flattened epithelial cells in the lateral regions and give rise to supportive cells that encase a small number of receptor cells (10-15). The ampullary wall comprises several types of cells that are adjoined via tight junctions and desmosomes between cell types. The ovoid receptor cells possess microvilli along the luminar apical area. Beneath this area, the cells are rich in mitochondria and rough endoplasmic reticulum. An unmyelinated neuron adjoins with each receptor cell opposite multiple presynaptic bodies. This form of microampulla has not been previously described within the Family Plotosidae.     

Adrenal cortex and stomach lesions associated with stress in wild male African green monkeys (Cercopithecus aethiops) in the post-capture period

The objective of this study was to look for early pathological changes in stress target organs, adrenal glands, and stomachs in captured wild African green monkeys (AGMs). Three wild-caught male AGMs and seven singly housed wild AGMs were euthanized on day 1 and day 45 post-capture, respectively, and compared with four wild males euthanized with a rifle as controls. Morphometric analyses of the adrenal cortices and the cortical zones were done using an image analyzer. By day 45, the confined animals were clinically healthy, but had lost 47% mean body weight despite ad libitum feeding. The width of zona fasciculata in the controls was significantly smaller compared with that of 45-day monkeys (P < 0.05). Numerous acidophilic, hyperplastic and hypertrophic cells were present in the zona fasciculata of the 1-day confined AGMs. In the 45-day monkeys, there was glandular hyperplasia in the zona glomerulosa and the acini were distended and vacuous; yellow, granular pigmentation was distributed in the zona fasciculata. Acute stomach lesions represented by petechiation were seen in one monkey on day 1. Deep, circular, mucosal erosions, one to five in number and measuring from 0.5 to 1 mm in diameter, were present in three monkeys on day 45 post-capture. There were no adrenal cortex or stomach lesions in the rifle-shot monkeys. In conclusion, pathological lesions in the adrenal glands, and stomachs of the wild AGMs and weight loss occurred within the initial 45-day period following capture and confinement.     

Comparative cytomorphology of skin, lymph node, liver and bone marrow in patients with lepromatous leprosy1

OBJECTIVE: The aim of this study was to compare the cytological changes in skin, lymph nodes, liver and bone marrow in patients with lepromatous leprosy. METHODS: Skin lesion, lymph node, liver and bone marrow aspirates were analysed. May-Grunwald-Giemsa (MGG) and Ziehl-Neelsen (Z-N) stains were employed. Comparative cytomorphology was studied. RESULTS: Twenty patients with lepromatous leprosy were studied. Lepra cells (LC) predominated in the skin aspirates of 12 patients with lepromatous leprosy (LL), lymphocytes accompanied LC in eight patients with borderline-lepromatous (BL) leprosy. Three patients of LL leprosy and two of BL leprosy in type 2 reaction additionally had numerous neutrophils. Two patterns of lymph node aspirates were seen: partial replacement with few LC in a reactive lymphoid background (10), complete replacement with either only LC or LC in a background of degenerating neutrophils (10), the latter a feature of type 2 reaction. Liver aspiration was performed in seven patients and of bone marrow in eight patients. Occasional LC were present in five liver-aspirated patients, steatosis and Kupffer cell hyperplasia in four patients, and myelopoiesis in two patients. Bone marrow smears invariably had occasional LC and a relative increase in mature plasma cells; sea-blue histiocytes were seen in six patients. CONCLUSION: Lepra cells predominated in skin and lymph node aspirates with complete replacement. In comparison, liver, bone marrow and lymph node aspirates with partial replacement were dominated by a preponderance of cells native to these organs with only few or occasional LC.