Using the double-observer method to estimate detection probability of two cavity-nesting seabirds in Antarctica: the snow petrel (Pagodroma nivea) and the Wilson��s storm petrel (Oceanites oceanicus)

When estimating the size of seabird populations, count data may be biased due to various factors such as detection probability. Failing to account for detection probability in surveys may lead to an underestimate of population size and may compromise the ability to monitor trends if detection probability varies among surveys. Here, we use the double-observer method to estimate detection probability of cavity-nesting snow petrels (Pagodroma nivea) and Wilson’s storm petrels (Oceanites oceanicus) in East Antarctica. Estimates of single-visit detection probability of nesting/roosting adult snow petrels during the incubation stage of the breeding cycle ranged from 0.86 (SE = 0.04) to 0.87 (SE = 0.04) depending upon observers. Both observers found snow petrel chicks were easier to detect than adults, with estimated detection probability for chicks ranging from 0.92 (SE = 0.03) to 1.00 (SE = 0.34 × 10⁻⁵). Detection probability of adult and chick snow petrels increased as cavity volume increased. Compared to snow petrels, estimated detection probability was considerably lower for nesting/roosting Wilson’s storm petrels, ranging from 0.27 (SE = 0.09) to 0.50 (SE = 0.13) for each observer. These estimates of detection probability apply only to those individuals in the population that were potentially viewable or audible. Nevertheless, our results indicate that double-observer counts for ground surveys of cavity-nesting seabirds should improve estimates of population abundance in comparison with single-visit counts. Accounting for observer effects, habitat characteristics and stage of the breeding season on detection probability should also improve estimation of population trends.     

Whole plant response of Pongamia pinnata to drought stress tolerance revealed by morpho-physiological,biochemical and transcriptome analysis

Molecular Biology Reports - Pongamia is considered an important biofuel species worldwide. Drought stress in the early growth stages of Pongamia influences negatively on the germination and...     

Nucleotide sequence of the gene encoding the matrix protein of Newcastle disease virus.

The nucleotide sequence of the gene encoding the matrix (M) protein of the Beaudette C strain of Newcastle disease virus (NDV) has been determined from overlapping cDNA clones. Control sequences typical of paramyxovirus mRNA start and polyadenylation signals have been identified. Assuming that the M gene starts and finishes at these sequences, the M gene is 1241 nucleotides long and encodes one long open reading frame of 364 amino acids, corresponding to a polypeptide of molecular weight 39605, in good agreement with estimates from SDS gels. The M protein has an amino acid sequence that is both hydrophobic and highly basic. The NDV M protein has sequence homologies to the M proteins of Sendai, measles, canine distemper and respiratory syncytial viruses.     

Positions of multiple insertions in SSU rDNA of lichen-forming fungi

Lichen-forming fungi, in symbiotic associations with algae, frequently have nuclear small subunit ribosomal DNA (SSU rDNA) longer than the 1,800 nucleotides typical for eukaryotes. The lichen-forming ascomycetous fungus Lecanora dispersa contains insertions at eight distinct positions of its SSU rDNA; the lichen-forming fungi Calicium tricolor and Porpidia crustulata each contain one insertion. Insertions are not limited to fungi that form lichens; the lichen ally Mycocalicium albonigrum also contains two insertions. Of the 11 insertion positions now reported for lichen-forming fungi and this ally, 6 positions are known only from lichen-forming fungi. Including the 4 newly reported in this study, insertions are now known from at least 17 positions among all reported SSU rDNA sequences. Insertions, most of which are Group I introns, are reported in fungal and protistan lineages and occur at corresponding positions in genomes as phylogenetically distant as the nuclei of fungi, green algae, and red algae. Many of these positions are exposed in the mature rRNA tertiary structure and may be subject to independent insertion of introns. Insertion of introns, accompanied by their sporadic loss, accounts for the scattered distribution of insertions observed within the SSU rDNA of these diverse organisms.      

Localization of the 5-phospho-alpha-D-ribosyl-1-pyrophosphate binding site of human hypoxanthine-guanine phosphoribosyltransferase.

Human erythrocyte hypoxanthine-guanine phosphoribosyltransferase (HPRT) is inactivated by iodoacetate in the absence, but not in the presence, of the substrate, 5-phospho-alpha-D-ribosyl-1-pyrophosphate (PRib-PP). Treatment of HPRT with [14C]iodoacetate followed by tryptic digestion, peptide separation and sequencing has shown that Cys-22 reacts with iodoacetate only in the absence of PRib-PP; this strongly suggests that Cys-22 is in or near the PRib-PP binding site. In contrast, Cys-105 reacts with [14C]iodoacetate both in the presence and absence of PRib-PP. Carboxymethylation of Cys-22 resulted in an increase in the Km for PRib-PP, but no change in Vmax. Storage of HPRT also resulted in an increase in the Km for PRib-PP and a decrease in its susceptibility to inactivation by iodoacetate. Dialysis of stored enzyme against 1 mM dithiothreitol resulted in a marked decrease in Km for PRib-PP. The stoichiometry of the reaction of [14C]iodoacetate with Cys-22 in HPRT leading to inactivation (approx. 1 residue modified per tetramer) showed that, in this preparation of HPRT purified from erythrocytes, only about 25% of the Cys-22 side chains were present as free and accessible thiols. Titration of thiol groups [with 5,5'-dithiobis(2-nitrobenzoic acid)] and the effect of dithiothreitol on Km for PRib-PP indicate that oxidation of thiol groups occurs on storage of HPRT, even in the presence of 1 mM beta-mercaptoethanol.