Facultative response to a kleptoparasite by the cooperatively breeding pied babbler

In many cases of interspecific kleptoparasitism, hosts developdefensive behaviors to minimize the impact of kleptoparasites.Because vigilance and defensive behaviors are often costly,selection should favor hosts that adjust the amount of investmentneeded to minimize losses to kleptoparasitism. However, examplesof such facultative responses are rare. Here, we investigatethe response of cooperatively breeding pied babblers (Turdoidesbicolor) to the drongo (Dicrurus adsimilis), an avian kleptoparasitethat regularly follows pied babbler groups, often giving alarmcalls to alert the group to predators but also occasionallygiving false alarm calls in order to steal food items. We showthat pied babbler response to drongos varies markedly accordingto babbler group size. In small groups, where there are fewindividuals available to act as sentinels, babblers sentinelless when a drongo is present and respond strongly to drongoalarm calls. However, in large groups, where there are manyindividuals available to participate in predator vigilance,babblers sentinel more often when a drongo is present, rarelyrespond to drongo alarm calls, and aggressively displace drongos,with a consequent decline in the number of successful kleptoparasitismevents. This behavior represent a facultative response to akleptoparasite according to the costs versus benefits of toleratingtheir presence.     

Structured growth and genetic drift raise relatedness in the social amoeba Dictyostelium discoideum

One condition for the evolution of altruism is genetic relatedness between altruist and beneficiary, often achieved through active kin recognition. Here, we investigate the power of a passive process resulting from genetic drift during population growth in the social amoeba Dictyostelium discoideum. We put labelled and unlabelled cells of the same clone in the centre of a plate, and allowed them to proliferate outward. Zones formed by genetic drift owing to the small population of actively growing cells at the colony edge. We also found that single cells could form zones of high relatedness. Relatedness increased at a significantly higher rate when food was in short supply. This study shows that relatedness can be significantly elevated before the social stage without a small founding population size or recognition mechanism.     

Mannose-binding lectin deficiency is associated with early onset of polyarticular juvenile rheumatoid arthritis: a cohort study

Background  

Mannose-binding lectin (MBL) is an innate immune protein. The aim of our study was to determine whether genetically determined MBL deficiency is associated with susceptibility to juvenile rheumatoid arthritis (JRA) and whether MBL2 genotypes are associated with JRA severity.     

The effects of added purines on urate and purine synthesis de novo by isolated chick liver, kidney and lymphoid cells.

1. Isolated chick lymphoid cells, together with isolated chick liver and kidney cells, incorporate [1-14C]glycine or [14C]formate into urate. 2. Of the cell types used, bursal cells incorporate 14C into urate at the fastest rate, although the output of total urate by bursal cells is only 10% that of liver cells. 3. When suspended in Eagle's medium the incorporation of 14C into urate is inhibited by adenine and guanine up to 1 mM. In contrast, the addition of 1 mM-AMP or -GMP results in a relatively large stimulation of this incorporation. 4. Added adenine is rapidly taken up by liver cells and then released in an unmetabolized form; AMP is taken up more slowly and is rapidly metabolized. The metabolites (possibly including adenine) are then released. 5. Intracellular liver 5-phosphoribosyl 1-pyrophosphate is approx. 0.7mM and remains constant or falls slightly during a 3 h incubation of the cells. 6. The addition of adenine or guanine, AMP or GMP, does not alter liver intracellular 5-phosphoribosyl 1-pyrophosphate concentrations. Added 5-phosphoribosyl 1-pyrophosphate is not taken up by liver cells. 7. The results are discussed in the context of the control of urate and purine synthesis de novo in the chick.     

Androgen receptors in skeletal muscle cytosol from sheep treated with trenbolone acetate

Female sheep were implanted with the anabolic agent trenbolone acetate and the effects of the treatment on the skeletal muscle androgen receptor studied. In two separate trials the binding capacity/mg skeletal muscle protein was reduced. In trial 1 the animals were implanted (80 mg trenbolone acetate) at the start and after 5 weeks of the trial and samples taken one week later while in the second trial samples were taken 15 days after a single implant (80 mg trenbolone acetate). The ability of a variety of steroids and steroid-like compounds to displace [3H] testosterone and [3H] methyltrienolone was also studied. The androgen receptor was also partially purified using heparin-sepharose chromatography The involvement of the anddrogen receptor in the mode of action of trenbolone is discussed.     

Human immunoglobulin subclasses. Partial amino acid sequence of the constant region of a γ4 chain

The heavy chain of a human myeloma protein (Vin) belonging to the gamma4 subclass was subjected to tryptic digestion after reduction and carboxymethylation. Cyanogen bromide fragments were also prepared and all 19 tryptic peptides that account for one of them (the Fc-like fragment) were studied. Selected peptic peptides were isolated and provided evidence for the order of 15 of the tryptic peptides. In addition the sequence of two large peptic peptides derived from two sections of the molecule including all the interchain bridges is presented. Comparison with published data on other chains allows us to propose a sequence of gamma4 chains that extends from just before the presumed starting point of the invariable region (at about residue 113) to the C-terminal end of the chain (approx. residue 446), except for a section of about 50 residues. The results of the comparison suggest that the immunoglobulin subclasses have a recent independent evolutionary origin in different species. Implications for complement fixation and for the evolutionary origin of antibody diversity are also discussed.     

Immunological detection of nitric oxide synthase(s) in human tissues using heterologous antibodies suggesting different isoforms

Summary Nitric oxide (NO) is generated from l-arginine by NO synthases. Localization of the brain enzyme has been carried out in the rat; however, despite data suggesting that NO is a major regulator of vascular and neural functions in man, there is no information about the localization of NO synthase in human tissues. Rabbit antisera to NO synthase purified from rat brain (antisera A and B) were raised, tested by Western blotting, affinity purification and enzyme immunoprecipitation assay, and used to investigate the distribution of the enzyme in a variety of human tissues by immunohistochemistry. Antisera to two synthetic peptides from cloned neural NO synthase were used to aid specificity testing. Antisera A and B reacted with a 160-kDa protein in Western blots of human brain extracts, gave immunostaining of nerves, and precipitated enzyme activity from rat brain homogenates. Antiserum B to NO synthase also reacted with proteins of M_r between 125 and 140 kDa in extracts of well-vascularised tissues, and immunostained vascular endothelium; the neural and vascular immunoreactivity persisted after affinity purification of antiserum B with the 160 kDa protein. Endothelial staining with antiserum B was seen in respiratory tract, liver, skin and umbilicus; syncytial trophoblasts stained in the placenta. Neural staining with antiserum A and B was seen in the myenteric and submucous plexus, and in nerve fibres in smooth muscle of the gut and in many areas of the central nervous system, particularly cortex, hippocampus, hypothalamus, cerebellum, brain stem and spinal cord. Therefore, antibodies to rat brain enzyme react with the human equivalent and also with other NO synthase isoforms in human endothelium. These findings support the contention that the endothelial enzyme is a different form with partial homology to that in nerves and also provide an anatomical distribution of NO synthase isoforms.Abbreviations NADPH -Nicotinamide adenine dinucleotide phosphate, reduced - FAD flavin adenine dinucleotide - FMN flavin mononucleotide - KLH keyhole limpet haemocyanin - G-MDP N-acetylmuramyl-l-ananyl-d-isoglutamine - TLCK N-p-tosyl-l-lysine chloro-methylketone - DRG dorsal root ganglia     

Purine metabolism and urate biosynthesis in isolated chicken hepatocytes

The metabolism of some purine compounds to urate and their effects on de novo urate synthesis in chicken hepatocytes were investigated. The purines, listed in descending order of rates of catabolism to urate, were hypoxanthine, xanthine, inosine, guanosine, guanine, IMP, GMP, adenosine, AMP, and adenine. During a 1-h incubation period, conversion to urate accounted for more than 80% of the total quantities of guanine, guanosine, and inosine metabolized, but only 42% of the adenosine and 23% of the adenine metabolism. Adenine, adenosine, and AMP inhibited de novo urate synthesis [( 14C]formate incorporation into urate), whereas the other purines, especially guanine, guanosine, and GMP, stimulated de novo urate synthesis. When hepatocytes were incubated with glutamine and adenosine, AMP, guanine, guanosine, or GMP, the rates of de novo urate synthesis were lower than the additive effects of glutamine and the purine in separate incubations. Increasing phosphate concentrations had no effect on urate synthesis in the absence of added purines but, in combination with adenosine, AMP, guanosine, or GMP, increased urate synthesis. These results indicate that the ratio of adenine to guanine nucleotides and the interaction between substrates and purine nucleotides are involved in the regulation of urate biosynthesis in chicken liver.     

First report of metazoan parasites from the cichlid Pseudocrenilabrus philander and the cyprinid Enteromius paludinosus in a South African Ramsar wetland

Parasites of two small fish species from a Ramsar wetland in South Africa were studied in 2014–2015. The cichlid Pseudocrenilabrus philander (Weber, 1897) was parasitised by the copepod Lernaea cyprinacea Linnaeus, 1758, the monogenean Gyrodactylus thlapi Christison, Shinn & van As, 2005 and four gryporhynchid metacestode (Cyclophyllidea) species: Paradilepis scolecina (Rudolph, 1819), Paradilepis maleki Khalil, 1961, Neogryporhynchus lasiopeius Baer & Bona, 1960 and Valipora campylancristrota (Wedl, 1855). The cyprinid Enteromius paludinosus (syn. Barbus paludinosus) (Peters, 1852) was infected with the monogenean parasites Dogielius intorquens Crafford, Luus-Powell & Avenant-Oldewage, 2012, Dactylogyrus teresae Mashego, 1983, and three Dactylogyrus spp. These results represent several new locality as well as host records and further contribute information on the parasitic diversity in the Barberspan Ramsar wetland.