Fibrillin-2 is dispensable for peripheral nerve development,myelination and regeneration

The extracellular matrix of peripheral nerve is formed from a diverse set of macromolecules, including glycoproteins, collagens and proteoglycans. Recent studies using knockout animal models have demonstrated that individual components of the extracellular matrix play a vital role in peripheral nerve development and regeneration. In this study we identified fibrillin-1 and fibrillin-2, large modular structural glycoproteins, as components of the extracellular matrix of peripheral nerve. Previously it was found that fibrillin-2 null mice display joint contractures, suggesting a possible defect of the peripheral nervous system in these animals. Close examination of the peripheral nerves of fibrillin-2 deficient animals described here revealed some structural abnormalities in the perineurium, while general structure of the nerve and molecular composition of nerve extracellular matrix remained unchanged. We also found that in spite of the obvious motor function impairment, fibrillin-2 null mice failed to display changes of nerve conduction properties or nerve regeneration capacity. Based on the data obtained we can conclude that peripheral neuropathy should be excluded as the cause of the impairment of locomotory function and joint contractures observed in fibrillin-2 deficient animals.     

1,7-Disubstituted oxyindoles are potent and selective EP3 receptor antagonists

A series of novel 1,7-disubstituted oxyindoles were shown to be potent and selective EP₃ receptor antagonists. Variation of substitution pattern at the C-3 position of indole enhanced in vitro metabolic stability of the resulting derivatives. Series 27a–c showed >1000-fold selectivity over a panel of prostanoid receptors including IP, FP, EP₁, EP₂ and EP₄. These agents also featured low CYP inhibition and good activity in the functional rat platelet aggregation assay.     

Involvement of lectin pathway activation in the complement killing of Giardia intestinalis

Giardia intestinalis (syn. G. lamblia, G. duodenalis) is a flagellated unicellular eukaryotic microorganism that commonly causes diarrheal disease throughout the world. In humans, the clinical effects of Giardia infection range from the asymptomatic carrier state to a severe malabsorption syndrome possibly due to different virulence of the Giardia strain, the number of cysts ingested, the age of the host, and the state of the host immune system at the time of infection.The question about how G. intestinalis is controlled by the organism remains unanswered. Here, we investigated the role of the complement system and in particular, the lectin pathway during Giardia infections. We present the first evidence that G. intestinalis activate the complement lectin pathway and in doing so participate in eradication of the parasite. We detected rapid binding of mannan-binding lectin, H-ficolin and L-ficolin to the surface of G. intestinalis trophozoites and normal human serum depleted of these molecules failed to kill the parasites. Our finding provides insight into the role of lectin pathway in the control of G. intestinalis and about the nature of surface components of parasite.     

Phase 2 study of canfosfamide in combination with pegylated liposomal doxorubicin in platinum and paclitaxel refractory or resistant epithelial ovarian cancer

We have reviewed the pivotal presentations related to gastrointestinal malignancies from 2009 annual meeting of the American Society of Clinical Oncology with the theme of "personalizing cancer care". We have discussed the scientific findings and the impact on practice guidelines and ongoing clinical trials. Adding trastuzumab to chemotherapy improved the survival of patients with advanced gastric cancer overexpressing human epidermal growth factor receptor 2. Gemcitabine plus cisplatin has become a new standard for first-line treatment of advanced biliary cancer. Octreotide LAR significantly lengthened median time to tumor progression compared with placebo in patients with metastatic neuroendocrine tumors of the midgut. Addition of oxaliplatin to fluoropyrimidines for preoperative chemoradiotherapy in patients with stage II or III rectal cancer did not improve local tumor response but increased toxicities. Bevacizumab did not provide additional benefit to chemotherapy in adjuvant chemotherapy for stage II or III colon cancer. In patients with resected stage II colon cancer, recurrence score estimated by multigene RT-PCR assay has been shown to provide additional risk stratification. In stage IV colorectal cancer, data have supported the routine use of prophylactic skin treatment in patients receiving antibody against epidermal growth factor receptor, and the use of upfront chemotherapy as initial management in patients with synchronous metastasis without obstruction or bleeding from the primary site.     

Candida albicans PEP12 Is Required for Biofilm Integrity and In Vivo Virulence

To investigate the role of the prevacuolar secretion pathway in biofilm formation and virulence in Candida albicans, we cloned and analyzed the C. albicans homolog of the Saccharomyces cerevisiae prevacuolar trafficking gene PEP12. C. albicans PEP12 encodes a deduced t-SNARE that is 28% identical to S. cerevisiae Pep12p, and plasmids bearing C. albicans PEP12 complemented the abnormal vacuolar morphology and temperature-sensitive growth of an S. cerevisiae pep12 null mutant. The C. albicans pep12 Δ null mutant was defective in endocytosis and vacuolar acidification and accumulated 40- to 60-nm cytoplasmic vesicles near the plasma membrane. Secretory defects included increased extracellular proteolytic activity and absent lipolytic activity. The pep12Δ null mutant was more sensitive to cell wall stresses and antifungal agents than the isogenic complemented strain or the control strain DAY185. Notably, the biofilm formed by the pep12Δ mutant was reduced in overall mass and fragmented completely upon the slightest disturbance. The pep12Δ mutant was markedly reduced in virulence in an in vitro macrophage infection model and an in vivo mouse model of disseminated candidiasis. These results suggest that C. albicans PEP12 plays a key role in biofilm integrity and in vivo virulence.In Saccharomyces cerevisiae, distinct secreted marker proteins are trafficked differentially through a prevacuolar compartment (PVC) prior to exocytosis (14). Furthermore, prevacuolar protein sorting genes play an important role in cargo transport in the prevacuolar branch of the exocytic pathway in S. cerevisiae (13, 15). By isolating dense- and light-vesicle populations in S. cerevisiae vps1 sec6-4, vps4 sec6-4, and pep12 sec6-4 mutants, it was observed that mutants blocked in this prevacuolar pathway missort marker proteins that are normally found in high-density post-Golgi compartment vesicles into low-density vesicles (15). Gurunathan et al. (13) also demonstrated these findings for vps1 and pep12 mutants with a late secretory mutant (snc1) background similar to that of the sec6-4 strains. These results indicate that some exocytic cargo, including the conditionally regulated soluble secretory proteins invertase and acid phosphatase, are differentially sorted through a PVC prior to exocytosis in the model yeast S. cerevisiae.To study the prevacuolar branch of exocytosis in Candida albicans and its role in virulence, we have previously cloned and analyzed the C. albicans prevacuolar trafficking genes VPS1 and VPS4. We demonstrated that C. albicans VPS4 is required for extracellular secretion of Sap2p and Sap4-6p and for virulence in an in vivo model of disseminated candidiasis (19, 20). C. albicans VPS1 is required for Sap2p secretion and biofilm formation (4). Interestingly, although the C. albicans null mutant lacking VPS4 forms a biofilm that is denser than that formed by the isogenic reintegrant strain, the conditional mutant lacking VPS1 expression forms a patchy biofilm of reduced density (4, 34). Thus, it appears that interference with normal prevacuolar trafficking affects both the secretion of virulence-associated proteins and biofilm formation.S. cerevisiae PEP12 encodes a 288-amino-acid syntaxin which regulates docking of Golgi compartment-derived transport vesicles at the PVC (3). Pep12p interacts with the v-SNARE Vti1p, and overexpression of Pep12p suppresses extracellular missorting of carboxypeptidase in the vti1 mutant (37). The S. cerevisiae pep12 null mutant displays a temperature-sensitive growth defect and is characterized by an enlarged vacuole with morphology defined as class D (3). A search of the C. albicans genome database identified a structural homolog of S. cerevisiae PEP12. Thus, the experiments described below were designed to determine whether the C. albicans PEP12 homolog is functionally homologous to S. cerevisiae PEP12 and to investigate its role in secretion, biofilm formation, and virulence.     

Characterization and experimental infection of Flexibacter maritimus (Wakabayashi et al. 1986) in hatcheries of post-larvae of Litopenaeus vannamei Boone, 1931.

A preliminary study to characterize filamentous bacteria, whose presence is related to high mortality of Litopenaeus vannamei larvae cultured in Santa Catarina State, Brazil, is reported. The extract of infected larvae was diluted in different concentrations, cultured in marine agar (Difco, Marine Agar 2216) and incubated at 30 degrees C for 48 hours. The biochemical characterization included hydrolytic reactions of starch, gelatin and tyrosine, growth in TCBS agar, growth in 0 and 37 per thousand salinity, pigment production in tyrosine agar, production of H2S, nitrate reduction, congo red reaction, oxidase and catalase. The isolated bacteria belong to the species Flexibacter maritimus, Gram-negative bacilli of 0.4-0.5 microm width and 15 microm length. Experiments were carried out on pathogenicity of F. maritimus in post-larvae of L. vannamei. Survival and symptoms in L. vannamei post-larvae 24 hours after inoculation with F. maritimus and its growth in marine agar were evaluated. Mortality was detected around 92,5% as well as symptoms like melanized lesions in several parts of body, discolouration of gills, bad formation of appendages and of the last abdominal segment, low motility and feeding reduction. The experimental infection results suggested that isolated bacteria of the genus Flexibacter are pathogenic to the shrimp Litopenaeus vannamei post-larvae.     

Effect of <Emphasis Type="Italic">Agave tequilana</Emphasis> juice on cell wall polysaccharides of three <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> strains from different origins

In this study, a characterization of cell wall polysaccharide composition of three yeasts involved in the production of agave distilled beverages was performed. The three yeast strains were isolated from different media (tequila, mezcal and bakery) and were evaluated for the β(1,3)-glucanase lytic activity and the β-glucan/mannan ratio during the fermentation of Agave tequilana juice and in YPD media (control). Fermentations were performed in shake flasks with 30 g l⁻¹ sugar concentration of A. tequilana juice and with the control YPD using 30 g l⁻¹ of glucose. The three yeasts strains showed different levels of β-glucan and mannan when they were grown in A. tequilana juice in comparison to the YPD media. The maximum rate of cell wall lyses was 50% lower in fermentations with A. tequilana juice for yeasts isolated from tequila and mezcal than compared to the bakery yeast.     

Angiotensin II type 1 receptor blockade attenuates TGF-beta-induced failure of muscle regeneration in multiple myopathic states

Skeletal muscle has the ability to achieve rapid repair in response to injury or disease. Many individuals with Marfan syndrome (MFS), caused by a deficiency of extracellular fibrillin-1, exhibit myopathy and often are unable to increase muscle mass despite physical exercise. Evidence suggests that selected manifestations of MFS reflect excessive signaling by transforming growth factor (TGF)-beta (refs. 2,3). TGF-beta is a known inhibitor of terminal differentiation of cultured myoblasts; however, the functional contribution of TGF-beta signaling to disease pathogenesis in various inherited myopathic states in vivo remains unknown. Here we show that increased TGF-beta activity leads to failed muscle regeneration in fibrillin-1-deficient mice. Systemic antagonism of TGF-beta through administration of TGF-beta-neutralizing antibody or the angiotensin II type 1 receptor blocker losartan normalizes muscle architecture, repair and function in vivo. Moreover, we show TGF-beta-induced failure of muscle regeneration and a similar therapeutic response in a dystrophin-deficient mouse model of Duchenne muscular dystrophy.