Two different molecular defects in the Tva receptor gene explain the resistance of two tvar lines of chickens to infection by subgroup A avian sarcoma and leukosis viruses

The subgroup A to E avian sarcoma and leukosis viruses (ASLVs) are highly related and are thought to have evolved from a common ancestor. These viruses use distinct cell surface proteins as receptors to gain entry into avian cells. Chickens have evolved resistance to infection by the ASLVs. We have identified the mutations responsible for the block to virus entry in chicken lines resistant to infection by subgroup A ASLVs [ASLV(A)]. The tva genetic locus determines the susceptibility of chicken cells to ASLV(A) viruses. In quail, the ASLV(A) susceptibility allele tva(s) encodes two forms of the Tva receptor; these proteins are translated from alternatively spliced mRNAs. The normal cellular function of the Tva receptor is unknown; however, the extracellular domain contains a 40-amino-acid, cysteine-rich region that is homologous to the ligand binding region of the low-density lipoprotein receptor (LDLR) proteins. The chicken tva(s) cDNAs had not yet been fully characterized; we cloned the chicken tva cDNAs from two lines of subgroup A-susceptible chickens, line H6 and line 0. Two types of chicken tva(s) cDNAs were obtained. These cDNAs encode a longer and shorter form of the Tva receptor homologous to the Tva forms in quail. Two different defects were identified in cDNAs cloned from two different ASLV(A)-resistant inbred chickens, line C and line 7(2). Line C tva(r) contains a single base pair substitution, resulting in a cysteine-to-tryptophan change in the LDLR-like region of Tva. This mutation drastically reduces the binding affinity of Tva(R) for the ASLV(A) envelope glycoproteins. Line 7(2) tva(r2) contains a 4-bp insertion in exon 1 that causes a change in the reading frame, which blocks expression of the Tva receptor.     

Antinociceptive potency of a fluorinated cyclopeptide Dmt-c[D-Lys-Phe-p-CF3-Phe-Asp]NH2

Opioid peptides and opiate drugs such as morphine, mediate their analgesic effects, but also undesired side effects, mostly through activation of the mu opioid receptor. However, delta- and kappa-opioid receptors can also contribute to the analgesic effects of opioids. Recent findings showed that simultaneous activation of multiple opioid receptors may result in additional analgesia with fewer side effects. Here, we evaluated the pharmacological profile of our formerly developed mixed mu/kappa-opioid receptor ligands, Dmt-c[D-Lys-Phe-Phe-Asp]NH₂ (C-36) and Dmt-c[D-Lys-Phe-p-CF₃-Phe-Asp]NH₂ (F-81). The ability of these peptides to cross the blood–brain barrier was tested in the parallel artificial membrane permeability (PAMPA) assay. On the basis of the hot-plate test in mice after central and peripheral administration, analog F-81 was selected for the anti-nociceptive and anti-inflammatory activity assessment after peripheral administration.     

Kanamycin induces free radicals formation in melanocytes: An important factor for aminoglycosides ototoxicity

Ototoxicity is well-documented but not fully understood undesirable side effect of aminoglycoside antibiotic, kanamycin. Kanamycin is capable of binding to melanin biopolymers—natural pigments of the skin, hair, and eyes. Melanin-producing cells, melanocytes, are also present in the inner ear and are known to be necessary for normal hearing. It was considered that melanin content in the inner ear may influence aminoglycoside-induced ototoxic effect. The impact of kanamycin on melanocytes homeostasis may thus play role in the antibiotic-induced ototoxic effect. Previously, we demonstrated that kanamycin disturbs homeostasis in light-pigmented melanocytes. To investigate if/how melanization contributes to this phenomenon, the study using in vitro model of dark-pigmented melanocytes is required. Spectrophotometric measurements and electron paramagnetic resonance (EPR) spectroscopy analysis were performed. Kanamycin induced a concentration-dependent loss in HEMn-DP melanocytes viability. The value of IC ₅₀ was estimated to be 5.0 mM. Modulation of the activity of analyzed antioxidant enzymes and increased production of free radicals as well as the decrease of the melanin content were observed. Our results confirmed that kanamycin generates oxidative stress in melanocytes. The increased level of free radicals caused by kanamycin may be responsible for the imbalance of antioxidant defense and the reduction of melanin content in melanocytes. The role of melanin in the mechanism of kanamycin-induced hearing impairment was discussed and the obtained results were compared with the previously demonstrated data concerning light-pigmented melanocytes.     

Twenty-four hour changes in lysozyme levels, total plasma protein concentration, gamma-globulin concentration, white blood cell count and numbers of lymphocytes and granulocytes in the peripheral blood of chinchillas Chinchilla laniger M. and rabbits Oryctolagus cuniculus L

Twenty-four hour changes in lysozyme level, total plasma protein concentration, gamma-globulin concentration, leucocyte number and different forms of leucocyte in the peripheral blood of male chinchillas and rabbits were investigated. All investigated parameters in both species showed statistically significant 24-hr changes, but only total plasma protein concentration in rabbits and gamma-globulin concentration and leucocyte number in chinchillas have a circadian rhythm character. The cosine curve characteristics for these rhythms are as follows; acrophases 0.45 + 2.18 hr, 10.02 + 4.29 hr, 2.14 + 3.20 hr; amplitudes 0.48 + 0.32 g%, 0.34 + 0.41 g%, 1.12 + 0.88 X 10(3)/min3; mesors 6.10 + 0.22 g%, 2.23 + 0.21 g%, 8.78 + 0.65 X 10(3)/mm3, respectively.     

Maternal investment in a bee species with facultative nest guarding and males heavier than females

1. Maternal investment can be influenced by several factors, especially maternal quality and possibilities for future reproduction. Mass provisioning Hymenoptera are an excellent group for measuring maternal investment because mothers distribute food sources to each brood cell for each offspring separately. Generally in aculeate Hymenoptera, larger females produce larger offspring and invest more in female offspring than in male offspring. 2. This study investigated patterns of maternal investment in Ceratina chalcites, which has an uncommon type of sexual size dimorphism in Hymenoptera: on average, males are heavier than females. It was found that larger females produce a significantly higher proportion of male offspring, as males are the costlier sex in this species. 3. Facultative nest guarding by females was observed. Females can guard offspring until adulthood, as is typical for bees of genus Ceratina (34.43% of nests); however, in the majority of cases (65.56% of nests), females plug and abandon the nest. Significant differences were found in the amount of investment between guarded and unguarded nests. Guarded nests had a greater number of provisioned brood cells and a higher proportion of male offspring. It is suggested that mothers have two facultative strategies – either she makes a large investment in the offspring of one nest or she abandons the first nest and carries out a second nesting elsewhere.     

Haematological and blood biochemical studies in female domesticated Indian elephants (Elaphas maximus L.)

1. Some haematological and biochemical blood parameters in female Indian elephants were investigated. 2. Haematological data were as follows: Ht = 39.2 +/- 2.36%, Hb = 10.1 +/- 0.54 g%, RBC = 2.66 +/- 0.32 x 10(6)/mm3, WBC = 5.43 +/- 0.48 x 10(3)/mm3. Lymphocytes, determined on blood smears were mainly leucocytes from (67.0 +/- 1.59%). Data for MCV, MCH and MCHC are also given. 3. Blood plasma was separated into 5 main fractions, total plasma protein concentration was 6.98 +/- 0.53 g%, A/G ratio was 0.69 +/- 0.1. 4. Plasma minerals concentration was as follows: Na, 3044 +/- 194 micrograms/ml; K, 529 +/- 38.5 micrograms/ml; Mg, 33.0 +/- 3.43 micrograms/ml; Ca, 181.0 +/- 17.8 micrograms/ml; InP, 44.6 +/- 6.1 micrograms/ml. Ca: P ratio was 3.25 +/- 0.34. 5. Some seasonal differences in investigated parameters were observed. Ht values, WBC and neutrophils number as well as Ca, and Mg concentrations were higher during winter, whereas RBC and Na and InP concentrations were lower in winter.     

Alarming declines in bird abundance in an Afromontane global biodiversity hotspot

Biodiversity and Conservation - Many natural ecosystems in tropical regions are under immense anthropogenic pressure, mostly connected with forest logging. However, several other factors may play...     

Molecular data do not support the current division of Orthotrichum (Bryophyta) species with immersed stomata

Genetic relationships between 27 Orthotrichum species of the subgenera Orthotrichum and Pulchella were reconstructed using the internal transcribed spacer regions 1 and 2,the chloroplast trnH-psbA regi...