The use of invertebrate functional groups to characterize ecosystem attributes in selected streams and rivers in south Brazil

An analysis conducted at nine stream/river sites in the Atlantic Forest region in the State of Paraná, Brazil used macroinvertebrate functional feeding group (FFG) assessments to evaluate ecological condition of the sites. The FFG approach categorizes qualitative macroinvertebrate collections according to their morphological-behavioral adaptations for food acquisition (e.g. scrapers that harvest non-filamentous, attached algae from stable surfaces in flowing water). FFG ratios were employed as surrogates for stream/river ecosystem attributes: balance between autotrophy and heterotrophy; linkage between riparian inputs of coarse particulate organic matter and in-stream food webs; relative dominance of fine particulate organic matter in transport (suspended load) compared to that deposited in the sediments; and geomorphic stability of the channel. The analyses indicated that all nine sites were heterotrophic, six of the nine carried expected levels of suspended organic load and showed below expected linkage with riparian inputs, and in only two were stable substrates limiting. The implications of the findings and recommendations for further analysis and modifications of the protocol are discussed.     

Docking studies on novel analogues of 8 methoxy fluoroquinolones against GyrA mutants of Mycobacterium tuberculosis

Background

Modeling of transmembrane domains (TMDs) requires correct prediction of interfacial residues for in-silico modeling and membrane insertion studies. This implies the defining of a target sequence long enough to contain interfacial residues. However, too long sequences induce artifactual polymorphism: within tested modeling methods, the longer the target sequence, the more variable the secondary structure, as though the procedure were stopped before the end of the calculation (which may in fact be unreachable). Moreover, delimitation of these TMDs can produce variable results with sequence based two-dimensional prediction methods, especially for sequences showing polymorphism. To solve this problem, we developed a new modeling procedure using the PepLook method. We scanned the sequences by modeling peptides from the target sequence with a window of 19 residues.

Results

Using sequences whose NMR-structures are already known (GpA, EphA1 and Erb2-HER2), we first determined that the hydrophobic to hydrophilic accessible surface area ratio (ASAr) was the best criterion for delimiting the TMD sequence. The length of the helical structure and the Impala method further supported the determination of the TMD limits. This method was applied to the IL-2Rβ and IL-2Rγ TMD sequences of Homo sapiens, Rattus norvegicus, Mus musculus and Bos taurus.

Conclusions

We succeeded in reducing the variation in the TMD limits to only 2 residues and in gaining structural information.     

Glucose lowering effect of transgenic human insulin-like growth factor-I from rice: <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis>studies

Background  

Human insulin-like growth factor-I (hIGF-I) is a growth factor which is highly resemble to insulin. It is essential for cell proliferation and has been proposed for treatment of various endocrine-associated diseases including growth hormone insensitivity syndrome and diabetes mellitus. In the present study, an efficient plant expression system was developed to produce biologically active recombinant hIGF-I (rhIGF-I) in transgenic rice grains.     

Disease-associated glycosylated molecular variants of human C-reactive protein activate complement-mediated hemolysis of erythrocytes in tuberculosis and Indian visceral leishmaniasis

Human C-reactive protein (CRP), as a mediator of innate immunity, removed damaged cells by activating the classical complement pathway. Previous studies have successfully demonstrated that CRPs are differentially induced as glycosylated molecular variants in certain pathological conditions. Affinity-purified CRPs from two most prevalent diseases in India viz. tuberculosis (TB) and visceral leishmaniasis (VL) have differential glycosylation in their sugar composition and linkages. As anemia is a common manifestation in TB and VL, we assessed the contributory role of glycosylated CRPs to influence hemolysis via CRP-complement-pathway as compared to healthy control subjects. Accordingly, the specific binding of glycosylated CRPs with erythrocytes was established by flow-cytometry and ELISA. Significantly, deglycosylated CRPs showed a 7–8-fold reduced binding with erythrocytes confirming the role of glycosylated moieties. Scatchard analysis revealed striking differences in the apparent binding constants (10⁴–10⁵ M⁻¹) and number of binding sites (10⁶–10⁷sites/erythrocyte) for CRP on patients’ erythrocytes as compared to normal. Western blotting along with immunoprecipitation analysis revealed the presence of distinct molecular determinants on TB and VL erythrocytes specific to disease-associated CRP. Increased fragility, hydrophobicity and decreased rigidity of diseased-erythrocytes upon binding with glycosylated CRP suggested membrane damage. Finally, the erythrocyte-CRP binding was shown to activate the CRP-complement-cascade causing hemolysis, even at physiological concentration of CRP (10 μg/ml). Thus, it may be postulated that CRP have a protective role towards the clearance of damaged-erythrocytes in these two diseases.     

Brugada-type Electrocardiographic Pattern Induced by Electrocution

Heart is one of the most frequently affected organs in electrocution. Electrical injury can cause life-threatening cardiac complications such as asystole, ventricular fibrillation, and myocardial rupture. In this case report, we describe a 22-yr-old male patient who sustained electric burn injury and presented with electrocardiogram showing transient Brugada type pattern.     

<Emphasis Type="Italic">In vitro</Emphasis> propagation of North American ginseng (<Emphasis Type="Italic">Panax quinquefolius</Emphasis> L.)

North American ginseng (NAG) (Panax quinquefolius L.) is a medicinally important plant with multiple uses in the natural health product industry. As seed propagation is time-consuming because of the slow growth cycle of the plant, in vitro propagation using a bioreactor system was evaluated as an effective approach to accelerate plant production. An efficient method was developed to multiply nodal explants of NAG using liquid-culture medium and a simple temporary immersion culture vessel. The effects of plant growth regulators, phenolics, and chemical additives (activated charcoal, melatonin, polyvinylpolypyrrolidone, and ascorbic acid) were evaluated on in vitro-grown NAG plants. The highest number (12) of shoots per single node was induced in half-strength Schenk and Hildebrandt basal medium containing 2.5 mg/l kinetin, in which 81% of the cultured nodes responded. In a culture medium with 0.5 mg/l α-naphthalene acetic acid (NAA), roots were induced in 78% of the explants compared to 50% with a medium containing indole-3-acetic acid. All of the resulting plants appeared phenotypically normal, and 93% of the rooted plants were established in the greenhouse. Phenolic production increased significantly (P < 0.05) over a 4-wk culture period with a negative impact on growth and proliferation. Activated charcoal (AC; 50 mg/l) significantly reduced total phenolic content and was the most effective treatment for increasing shoot proliferation. Shoot production increased as the phenolic content of the cultures decreased. The most effective treatment for NAG development from cultured nodal explants in the bioreactor was 2.5 mg/l kinetin, 0.5 mg/l NAA, and 50 mg/l AC in liquid culture medium. This protocol may be useful in providing NAG tissues or plants for a range of ginseng-based natural health products.     

Adrenergic influence of uterine muscle contractions stimulated by a glycoside from the root of Dalbergia saxatilis

The mechanism of uterine muscle contraction stimulated by a triterpenoid glycoside (dalsaxin) isolated from the root of D. saxatilis was investigated by in vitro methods in the rat. Dalsaxin caused a dose-related increase in uterine muscle contraction. The contraction was single and transient and was abolished by moderate doses of isoprenaline (1.80 nmol-0.40 mumol) and salbutamol (0.13-25 mumol). Adrenaline (9.10 nmol) also caused a reversible decrease (92.6%; P < 0.01) in myometrial contraction stimulated by this glycoside (0.24 mg/ml). Uterine muscle responses to dalsaxin (0.24 mg/ml) were enhanced by the beta-adrenergic receptor antagonist, propranolol, in a dose related manner. Atipamezole (1.50 ng/ml) but not prazosin (7.72 nmol-15.60 nmol) substantially reduced (80%; P < 0.01) myometrial contractions induced by this uterine spasmogen. The results suggest that dalsaxin enhances uterine muscle contraction by stimulating post junctional alpha 2-adrenergic receptors, presumably by inhibiting plasma membrane adenylate cyclase system and its associated increase in intracellular cAMP content.     

Lectin histochemistry for detecting cadmium-induced changes in the glycosylation pattern of rat placenta

Cadmium (Cd) is an industrial and environmental pollutant that produces toxic effects on gametogenesis, pre- and post-implantation embryos, and the placenta. Because the effects of acute Cd intoxication on the placenta are not well understood, we investigated changes in its glycosylated components in Cd treated dams at days 4, 7, 10 and 15 of gestation using lectin histochemistry. CdCl₂ was administered to pregnant rats; control animals received sterile normal saline. Placentas were processed for DBA, Con A, SBA, PNA, UEA-I, RCA-I and WGA lectin histochemistry to evaluate changes in the carbohydrate pattern of the placenta that might modify cell interactions and contribute to embryonic alterations. Lectin binding was analyzed in the yolk sac; trophoblast giant cells; trophoblast I, II and III; spongiotrophoblast cells and endovascular trophoblast cells in the chorioallantoic placenta. Our lectin binding patterns showed that Cd caused alteration of SBA and DBA labeling of trophoblast-derived cells, which suggested increased expressions of α and β GalNAc. Cd also caused decreased UEA-1 binding affinity, which indicated fewer α-L-Fuc residues in placentas of Cd treated dams. The nonreactivity in trophoblast I of the control placentas incubated with Con-A contrasted with the labeling in placentas of experimental dams, which indicated increased expression of terminal α-D-Man, and α-D-Glc residues. We found that Cd altered the reactivity of placenta to several lectins, which indicated modification of the glycotype presented by the fetal component of the placenta. We report that Cd exerts a deleterious effect on the glycosylation pattern of the placenta.