Factors influencing Willow Tit Poecile montanus site occupancy: a comparison of abandoned and occupied woods

The British Willow Tit Poecile montanus kleinschmidti underwent a decline of 85% between 1970 and 2003. The cause of this decline is unknown. However, several hypotheses have been put forward to account for it: competition from other tit species, predation by Great Spotted Woodpeckers Dendrocopos major and habitat change. In order to test these, woods that are currently occupied by Willow Tits were paired with woods (within 50 km) that had been abandoned by Willow Tits five or more years previously. Point counts for other tit species (potential competitors) and woodpecker species (potential predators) were carried out at ten evenly spaced points throughout each wood. Habitat variables were collected within a 50-m radius of where a Willow Tit was located (in the occupied woods) or where maps showed a Willow Tit had been located (for abandoned woods). No evidence was found for differences in numbers of potential competitor or potential predator species in abandoned and occupied woods. Soil water content was found to be higher at occupied sites. No other habitat features differed between the two categories of site. The drying up of British woods could therefore be implicated in the Willow Tit decline and this warrants further investigation.     

The Effect of Boron and Gibberellic Acid on the Senescence of Leaf Discs from Lycopersicon esculentum cv. Rutgers

When leaf discs of Lycopersicon esculentum Mill. cv. Rutgers were floated on solutions containing 4.33 × 10^–6 M gibberellic acid (GA₃), 1.0 ×x 10^–6M boron (B), separately and together, senescence was retarded with respect to controls. Degradation of chlorophyll, total protein, RNA, and DNA was delayed, and decreases in fresh weight and leaf disc diameter checked. The loss of chlorophyll, protein, RNA, DNA, fresh weight, and diameter were 10, 20, 30, 8, 28, and 0 per cent with GA₃ alone; 15, 25, 35, 8, 31, and 0 per cent with B alone; 8, 14, 25, 7, 25, and 0 per cent with GA₃ plus B; contrasted with 50, 40, 50, 9, 42, and 3 per cent for the controls. An analysis of variance was performed on all data except for disc diameter. All sources of variance were significantly or highly significant at the 1 per cent level except for the effect of boron on DNA level, which was significant only at the 2.5 per cent level. Retardation of senescence by GA₃ may be associated with the known ability of GA₃ to stimulate m-RNA and protein synthesis. The effect of boron may be due to an effect on sugar and starch balance, translocation of sugar, or on water balance, but more likely boron plays a role in nucleotide and protein metabolism in plants. Boron may be involved in the synthesis of DNA, a role perhaps mediated by GA₃.     

Identification and functional characterization of effectors in expressed sequence tags from various life cycle stages of the potato cyst nematode Globodera pallida

In this article, we describe the analysis of over 9000 expressed sequence tags (ESTs) from cDNA libraries obtained from various life cycle stages of Globodera pallida . We have identified over 50 G. pallida effectors from this dataset using bioinformatics analysis, by screening clones in order to identify secreted proteins up-regulated after the onset of parasitism and using in situ hybridization to confirm the expression in pharyngeal gland cells. A substantial gene family encoding G. pallida SPRYSEC proteins has been identified. The expression of these genes is restricted to the dorsal pharyngeal gland cell. Different members of the SPRYSEC family of proteins from G. pallida show different subcellular localization patterns in plants, with some localized to the cytoplasm and others to the nucleus and nucleolus. Differences in subcellular localization may reflect diverse functional roles for each individual protein or, more likely, variety in the compartmentalization of plant proteins targeted by the nematode. Our data are therefore consistent with the suggestion that the SPRYSEC proteins suppress host defences, as suggested previously, and that they achieve this through interaction with a range of host targets.     

Characterization of MTNR1A gene in terms of genetic variability in a panel of subtemperate and subtropical Indian sheep breeds

Seasonality of animals is an important adaptive trait for successful survival and production during limited food availability and extreme environmental conditions. Photoperiodic changes in day length are utilized by these seasonal animals as an important environmental cue for regulating their annual rhythms of reproduction cycles. Melatonin is an important hormone which is secreted by the pineal gland in proportion to darkness and its effect is mediated by melatonin receptor subtypes, principally MTNR1A. In the present study, polymorphism in the coding sequence at two important SNPs (C606T and G612A), known to be markers for out of season breeding in sheep were studied by PCR-RFLP in a panel of four breeds of sheep from subtemperate and subtropical arid conditions, respectively. The frequencies of ‘G’ and ‘A’ alleles with reference to G612A SNP did not differ considerably among all the breeds of sheep. Frequency of ‘T’ allele of the C606T SNP was found to be dominantly higher in subtemperate sheep breeds in comparison to subtropical sheep breeds. Identified SNPs in the coding region were mostly synonymous and did not lead to any change in conformation of the MTNR1A receptor protein.