The sensitive period for light and temperature regulation of sporangiophore development inPhycomyces

Light and temperature markedly influence sporangiophore development inPhycomyces blakesleeanus. Under normal conditions in the dark, low temperature drastically stimulates the production of dwarf sporangiophores (microphorogenesis) and inhibits that of giant sporangiophores (macrophorogenesis). These effects of low temperature could still be observed if applied only for a short period before sporangiophore initiation. Continuous white illumination strongly inhibits microphorogenesis and slightly stimulates macrophorogenesis. Short exposures to white light noticeably inhibit microphorogenesis and stimulate macrophorogenesis when given to mycelia grown for between 90 and 160 h at 14° C or 150 h or more at 10° C. These results indicate the existence in the mycelium of developmental stages for the regulation of sporangiophorogenesis by environmental signals.     

Intermediate Filaments of Schwann Cells

Abstract: Intermediate filaments were prepared from distal stumps of rabbit sciatic nerve 5 weeks after nerve section, at which time Schwann cells account for 85–90% of the cell area. A polypeptide of molecular weight 58,000 was the main component of this fraction. An antiserum raised in guinea pig against this polypeptide stained all cells present in the distal stump, as well as Schwann cells and 3T3 cells in culture. The identity of the molecular weight 58,000 polypeptide obtained from distal stumps with vimentin was proved with one and two-dimensional sodium dodecyl sulfate pol yacrylamide gel electrophoresis and with immunoautoradiography. It is concluded that the intermediate filament subunit of undifferentiated Schwann cells is vimentin. The possibility that Schwann cells in normal nerve may have another type of intermediate filament besides vimentin cannot be ruled out.     

DNA-COMPACT: DNA COMpression Based on a Pattern-Aware Contextual Modeling Technique

Genome data are becoming increasingly important for modern medicine. As the rate of increase in DNA sequencing outstrips the rate of increase in disk storage capacity, the storage and data transferring of large genome data are becoming important concerns for biomedical researchers. We propose a two-pass lossless genome compression algorithm, which highlights the synthesis of complementary contextual models, to improve the compression performance. The proposed framework could handle genome compression with and without reference sequences, and demonstrated performance advantages over best existing algorithms. The method for reference-free compression led to bit rates of 1.720 and 1.838 bits per base for bacteria and yeast, which were approximately 3.7% and 2.6% better than the state-of-the-art algorithms. Regarding performance with reference, we tested on the first Korean personal genome sequence data set, and our proposed method demonstrated a 189-fold compression rate, reducing the raw file size from 2986.8 MB to 15.8 MB at a comparable decompression cost with existing algorithms. DNAcompact is freely available at https://sourceforge.net/projects/dnacompact/for research purpose.     

Use of sodC versus ctrA for real-time polymerase chain reaction-based detection of Neisseria meningitidis in sterile body fluids

We evaluated the use of a newly described sodC-based real-time-polymerase chain reaction (RT-PCR) assay for detecting Neisseria meningitidis in normally sterile sites, such as cerebrospinal fluid and serum. The sodC-based RT-PCR assay has an advantage over ctrA for detecting nongroupable N. meningitidis isolates, which are commonly present in asymptomatic pharyngeal carriage. However, in our study, sodC-based RT-PCR was 7.5% less sensitive than ctrA. Given the public health impact of possible false-negative results due to the use of the sodC target gene alone, sodC-based RT-PCR for the diagnosis of meningococcal meningitis should be used with caution.     

First report of Lymnaea columella Say, 1817 (Pulmonata: Lymnaeidae) naturally infected with Fasciola hepatica (Linnaeus,1758) (Trematoda: Digenea) in Argentina

We report the first evidence of natural infection of Lymnaea columella with Fasciola hepatica in Argentina. A sample of 601 snails was collected in May 2003 in northeastern Corrientes, a province bounded on the north by Paraguay, on the east by Brazil and on the southeast by Uruguay. Among 500 examined snails, 44 (8.8%) were exclusively infected with F. hepatica. Parasite identification was based on morphological features of cercariae from snails, and of eggs and adult flukes from Wistar rats. We discuss the events suggesting that an enzootic transmission cycle of F. hepatica has been recently established in northeastern Corrientes.     

Efficient Bayesian Sample Size Calculation for Designing a Clinical Trial with Multi‐Cluster Outcome Data

Health care utilization and outcome studies call for hierarchical approaches. The objectives were to predict major complications following percutaneous coronary interventions by health providers, and to compare Bayesian and non‐Bayesian sample size calculation methods. The hierarchical data structure consisted of: (1) Strata: PGY4, PGY7, and physician assistant as providers with varied experiences; (2) Clusters: k_s providers per stratum; (3) Individuals: n_s patients reviewed by each provider. The main outcome event illustrated was mortality modeled by a Bayesian beta‐binomial model. Pilot information and assumptions were utilized to elicit beta prior distributions. Sample size calculations were based on the approximated average length, fixed at 1%, of 95% posterior intervals of the mean event rate parameter. Necessary sample sizes by both non‐Bayesian and Bayesian methods were compared. We demonstrated that the developed Bayesian methods can be efficient and may require fewer subjects to satisfy the same length criterion.     

Signaling pathways involved in pilocarpine-induced mucin secretion in rat submandibular glands

We have studied the signaling pathways involved in pilocarpine-induced mucin release in rat submandibular slices. Pilocarpine produced a significant increment of PGE2 levels and a positive (r=0.8870) and significant (p=0.0077) correlation between PGE2 production and mucin released was determined. The participation of PGE2 was confirmed by the use of indomethacin (indo) and of acetyl salicylic acid (ASA), cyclooxygenase inhibitors, which inhibited pilocarpine-induced mucin release. The muscarinic receptors involved in the regulation of mucin release were identified as M1 and M4 by the use of the selective acetylcholine receptors (mAChR) antagonists, pirenzepine, AF-DX 116, 4-DAMP and tropicamide. The secretory process was dependent on both, intracellular and extracellular calcium pools since it was inhibited by thapsigargin and verapamil. Cyclic AMP, nitric oxide synthase and PKC also participated in pilocarpine-induced mucin release. It is concluded that pilocarpine, by activation the M1 and M4 mAChR subtypes induces an increase of intracellular Ca2+ concentration ([Ca2+]I) and elevates cAMP levels, which in turn stimulates COX, PKC and NOS and promotes mucin exocytosis. PGE2 released induces cAMP accumulation which, together with PKC are involved in the PGE2 increased Ca2+/cAMP-regulated exocytosis. Thus, cAMP accumulation induced by cholinergic stimulation is, in part, the result of PGE2 production.     

Modeling cancer: integration of "omics" information in dynamic systems

The last 10 years have seen the rise of many technologies that produce an unprecedented amount of genome-scale data from many organisms. Although the research community has been successful in exploring these data, many challenges still persist. One of them is the effective integration of such data sets directly into approaches based on mathematical modeling of biological systems. Applications in cancer are a good example. The bridge between information and modeling in cancer can be achieved by two major types of complementary strategies. First, there is a bottom-up approach, in which data generates information about structure and relationship between components of a given system. In addition, there is a top-down approach, where cybernetic and systems-theoretical knowledge are used to create models that describe mechanisms and dynamics of the system. These approaches can also be linked to yield multi-scale models combining detailed mechanism and wide biological scope. Here we give an overall picture of this field and discuss possible strategies to approach the major challenges ahead.     

Serotonergic mechanisms of the lateral parabrachial nucleus in renal and hormonal responses to isotonic blood volume expansion

This study investigated the involvement of serotonergic mechanisms of the lateral parabrachial nucleus (LPBN) in the control of sodium (Na+) excretion, potassium (K+) excretion, and urinary volume in unanesthetized rats subjected to acute isotonic blood volume expansion (0.15 M NaCl, 2 ml/100 g of body wt over 1 min) or control rats. Plasma oxytocin (OT), vasopressin (VP), and atrial natriuretic peptide (ANP) levels were also determined in the same protocol. Male Wistar rats with stainless steel cannulas implanted bilaterally into the LPBN were used. In rats treated with vehicle in the LPBN, blood volume expansion increased urinary volume, Na+ and K+ excretion, and also plasma ANP and OT. Bilateral injections of serotonergic receptor antagonist methysergide (1 or 4 microg/200 etal) into the LPBN reduced the effects of blood volume expansion on increased Na+ and K+ excretion and urinary volume, while LPBN injections of serotonergic 5-HT(2a)/HT(2c) receptor agonist, 2.5-dimetoxi-4-iodoamphetamine hydrobromide (DOI; 1 or 5 microg/200 etal) enhanced the effects of blood volume expansion on Na+ and K+ excretion and urinary volume. Methysergide (4 microg) into the LPBN decreased the effects of blood volume expansion on plasma ANP and OT, while DOI (5 microg) increased them. The present results suggest the involvement of LPBN serotonergic mechanisms in the regulation of urinary sodium, potassium and water excretion, and hormonal responses to acute isotonic blood volume expansion.