Novel inhibition of proteoglycan synthesis and exocytosis by diethylcarbamazine in the Swarm rat chondrocyte

Pretreatment of cultured chondrosarcoma chondrocytes at 37 degrees C for 15 min with 15 mM diethylcarbamazine (DEC) followed by a 60-min pulse with [35S] sulfate in the presence of DEC resulted in an approximate 40% inhibition of synthesis and a 75% inhibition of secretion of 35S-proteoglycan. The inhibition was dose-related and was not due to a decrease in protein synthesis. Chondrocytes exposed for 75 min to 15 mM DEC, washed, incubated for 17 h in DEC-free medium, and then pulsed with [35S]sulfate showed no inhibition in the rate of synthesis of proteoglycan or in the per cent of radiolabeled proteoglycans exocytosed into the culture medium, indicating full reversibility of the inhibitory effect. When chondrocytes were incubated for 75 min with both 1 mM beta-D-xyloside and 15 mM DEC, secretion of beta-D-xyloside-bound 35S-glycosaminoglycan was inhibited by more than 70% despite an approximate 3-fold increase in intracellular 35S-macromolecules, as compared to cells exposed to beta-D-xyloside alone. Upon removal of DEC, the block in the secretion of beta-D-xyloside-bound 35S-glycosaminoglycans was reversed, although there was a 15-30-min lag in the initiation of exocytosis. Light and electron microscopic examination of chondrocytes after 75 min of incubation with 15 mM DEC revealed large vacuoles, a distended Golgi apparatus, and a distended endoplasmic reticulum which contained electron dense material. Upon removal of DEC, the vacuoles disappeared and distended organelles returned to their normal appearance between 15 and 30 min, coincident with the start of exocytosis of 35S-proteoglycan and beta-D-xyloside-bound 35S-glycosaminoglycan. These biochemical and morphological studies indicate that DEC treatment of chondrosarcoma chondrocytes alters the transport of molecules from the endoplasmic reticulum to the Golgi and the transport of molecules from the Golgi to the cell surface.     

Reconstructing evolution of sequences subject to recombination using parsimony

The parsimony principle states that a history of a set of sequences that minimizes the amount of evolution is a good approximation to the real evolutionary history of the sequences. This principle is applied to the reconstruction of the evolution of homologous sequences where recombinations or horizontal transfer can occur. First it is demonstrated that the appropriate structure to represent the evolution of sequences with recombinations is a family of trees each describing the evolution of a segment of the sequence. Two trees for neighboring segments will differ by exactly the transfer of a subtree within the whole tree. This leads to a metric between trees based on the smallest number of such operations needed to convert one tree into the other. An algorithm is presented that calculates this metric. This metric is used to formulate a dynamic programming algorithm that finds the most parsimonious history that fits a given set of sequences. The algorithm is potentially very practical, since many groups of sequences defy analysis by methods that ignore recombinations. These methods give ambiguous or contradictory results because the sequence history cannot be described by one phylogeny, but only a family of phylogenies that each describe the history of a segment of the sequences. The generalization of the algorithm to reconstruct gene conversions and the possibility for heuristic versions of the algorithm for larger data sets are discussed.     

Mechanische Verletzung des Plasmalemmas als mögliche Voraussetzunlg Für die Virsinfektion von Pflanzen

Mechanical injury of the plasmalemma As a possible pre requisite for virus infection of plants
A basic requirement of the infection in case of mechanical inoculation f viruses could be that the plasmalemma of cells is to be injured, for a clearance between cell wall and plasmalemma at the time of inoculation in cells, which are suitable for primary infection prevented the infection.
By means of the hypertonic concentration of 0.7 mol/l of the plasmolytica ethylenglycol, sucrose, glucose, sorbitol and mannitol, which permeate with different speeds, and by modifications of the mannitol treatment, a withdrawal of the plasmalemma to varied distances from the cell wall was induced in cell of the upper side of leaf disk from Nicotiana glutinosa and N tabacum "samsun" This could be observed microscopically in the leaf disks after embedding in liquid paraffin
Treated leaf disk were inoculated with tobacco mosaic virus and incubated floating on tap water
The infection rate, determined by the number of local lesions in case of leaf disks from Nicotiana glutinosa and by the extractable infectivity in case of "Samsun"proved to be dependent on the degree of withdrawal of the plasmalemma from the wall of cell of the upper disk side A strong withdrawal by rounding of the protoplasts in all or almost all cells, caused by the non permeating mannitol or sorbitol, did hardly permit infection     

Natural occurrence of sterigmatocystin in in-shell pecans.

The natural occurrence of sterigmatocystin (S) in in-shell pecans is reported. Aspergillus versicolor was not isolated from contaminated samples. Incidence of A. flavus and A. glaucus, species known to produce sterigmatocystin under laboratory conditions, was high (43 and 35%, respectively). Isolation data suggest sterigmatocystin may have been produced by one or both of these species.     

"Staying power"--absorbable vs. nonabsorbable

An experiment was designed to compare the "holding power" or "staying power" of absorbable (polyglycolic acid and polyglactin 910) and nonabsorbable (nylon) suture. The aim of this experiment was to determine what provides the lasting strength of the bond between soft tissues that are approximated or plicated. When correcting the rectus diastasis during abdominoplasty, we used nylon sutures in 15 patients and absorbable synthetic sutures in 15 other patients. We then marked the closed folds of the rectus sheath with small metal vascular clips. Two days later and approximately 6 months after operation an upright anteroposterior abdominal x-ray was taken and the position of the metal clips was compared in the test groups. Although there was usually slight separation of the clips after 6 months, no significant difference between the two groups was noted, thereby indicating that holding power is not related to type of suture material but more likely to fibroplasia.     

Estrogen dependent ciliogenesis in the chick oviduct

Both the hormone dependency and the morphological details of estrogen-dependent ciliogenesis in the shell gland of the chick oviduct were investigated. Ciliogenesis was initiated on day 3 of estrogen treatment, and progressively more cells became differentiated until, on day 10, 55% ciliation occurred with 17-estradiol (1 mg/day) and 75% ciliation occurred with diethylstilbestrol (1 mg/day). Simultaneous administration of progesterone with diethylstilbestrol (1 mg each/day for 10 days) caused a 50% depression in the number of ciliated cells on day 10. The rate of ciliogenesis was found to be affected by progesterone and the type of estrogen administered. The minimum stimulatory dose of estradiol was found to be between 0.01 mg/day and 0.05 mg/day. Ciliogenic cells were first recognized by the appearance of pro-basal bodies in the apical portion of the cell. Pro-basal body maturation and cilium formation were the same as those described for the chick trachea. Ciliogenesis in the chick was found to be homologous to estrogen-dependent ciliogenesis in various mammalian oviducts.     

Gap junction remodeling and altered connexin43 expression in the failing human heart

Gap junctions (GJ) are important determinants of cardiac conduction and the evidence has recently emerged that altered distribution of these junctions and changes in the expression of their constituent connexins (Cx) may lead to abnormal coupling between cardiomyocytes and likely contribute to arrhythmogenesis. However, it is largely unknown whether changes in the expression and distribution of the major cardiac GJ protein, Cx43, is a general feature of diverse chronic myocardial diseases or is confined to some particular pathophysiological settings. In the present study, we therefore set out to investigate qualitatively and quantitatively the distribution and expression of Cx43 in normal human myocardium and in patients with dilated (DCM), ischemic (ICM), and inflammatory cardiomyopathies (MYO). Left ventricular tissue samples were obtained at the time of cardiac transplantation and investigated with immunoconfocal and electron microscopy. As compared with the control group, Cx43 labeling in myocytes bordering regions of healed myocardial infarction (ICM), small areas of replacement fibrosis (DCM) and myocardial inflammation (MYO) was found to be highly disrupted instead of being confined to the intercalated discs. In all groups, myocardium distant from these regions showed an apparently normal Cx43 distribution at the intercalated discs. Quantitative immunoconfocal analyis of Cx43 in the latter myocytes revealed that the Cx43 area per myocyte area or per myocyte volume is significantly decreased by respectively 30 and 55% in DCM, 23 and 48% in ICM, and by 21 and 40% in MYO as compared with normal human myocardium. In conclusion, focal disorganization of GJ distribution and down-regulation of Cx43 are typical features of myocardial remodeling that may play an important role in the development of an arrhythmogenic substrate in human cardiomyopathies.     

A promising biotechnical approach to pest management of Diabrotica virgifera virgifera in Illinois maize fields under kairomonal shielding with the new MSD technique

Environmentally compatible and sustainable plant protection requires novel approaches to pest management characterized by minimal emphasis on toxicants. Classical toxicants traditionally dominated economic entomology for half a century. But worldwide problems with environmental pollution and with increasing resistance levels in all major pesticide classes and in many key insect species including Diabrotica virgifera virgifera (D.v.v.) strongly advocate a rethinking and a change in management paradigms used. Soft, minimally invasive, biological, biotechnical and cultural approaches should replace hard pesticides which are in favor up to now. Fortunately, pheromones, kairomones, plant attractants, better traps, new plant varieties and cultural methods like crop rotation, in short more sophisticated methods are now available as pressure for finding and exploring novel strategies increases. Facing this situation, a new biotechnical approach of population reduction of D.v.v., called "MSD" technique, is introduced. MSD is characterized as an approach combining mass trapping, shielding and deflecting of adult insects along an invisible odor barrier of synthetic kairomone which diminishes the flux of insects across a high capacity trap line baited with kairomone, thus reducing both the population fluctuation and number and its reproductive success within the shielded area. In the case of D.v.v. in Zea mays fields, effects realized by the MSD technique have been measured simultaneously by a number of independent criteria during the summers of 2003 and 2004 at 2 different locations in Illinois maize fields of up to one half hectare size. Results observed are statistically significant and cannot be explained by mass trapping alone. There is also an additional shielding and deflection, in short "diversion" effect whose basic sensory and behavioral mechanisms call for future exploration.