Understanding clonal diversity patterns through allozyme polymorphism in an endangered and geographically restricted Australian shrub, Zieria baeuerlenii and its implications for conservation.

An electrophoretic genetic analysis utilising starch gel electrophoresis was employed to assess clonality in endangered Zieria baeuerlenii populations distributed over an area of less than a kilometre square in Nowra (NSW). Eleven enzymes systems encoded by 19 loci (41 alleles) when assayed to estimate levels of genetic diversity within and among populations, revealed moderate levels of genetic diversity. Despite finding seven loci being fixed at a particular locus, 20 unique multilocus genotypes/clones restricted to a particular population were detected within a sample of 179 ramets collected from throughout the range of the species. The probability of finding any clone produced by sexual reproduction is <0.0025 and is further supported by the fact that reproduction appears to be exclusively by vegetative spread and there is virtually no pollen viability and seed production. The lack of seed set in this area may be due to additional factors inhibiting sexual reproduction. Overall, such genetic studies play a crucial role in devising conservation and management strategies for rare and endangered taxa.

Genetic diversity and phylogenetic relatedness among six endemic Pterostylis species (Orchidaceae; series Grandiflorae) of Western Australia, as revealed by allozyme polymorphisms.

Starch gel electrophoresis was employed to survey the allozyme polymorphism and phylogenetic relationships among 35 populations covering six closely related Western Australian endemic Pterostylis species (series Grandiflorae); viz P. rogersii, P. aspera, P. angusta, P. hamiltonii, P. scabra and P. aff. alata. The aim of this study was to determine intraspecific and interspecific genetic diversity and species relationships based on allozyme analysis. The frequencies of 56 alleles at 12 enzyme systems coded by 15 loci were determined along with a mean intraspecific genetic identity value. Allozyme markers clearly discriminated populations belonging to different species. Nei's genetic distance/identity co-efficient was used to measure the level of genetic differentiation among populations and species. Based on these values, a dendrogram was constructed which revealed that all the populations clustered into groups corresponding to the respective species. Gene diversity analysis among all the species revealed total genetic diversity H(t) of 0.23 with co-efficient of gene differentiation 10% (G(st)=0.10). Mean genetic variability (H(e)=0.136, P=40%) was also higher than for other outbreeding plant species. Mean genetic identity coefficient of populations of all species was 0.859 which increased to 0.877 upon exclusion of P. aff. alata, indicating a high degree of similarity among all species except P. aff. alata which segregated distinctively from the rest. Overall, the investigation provided independent support for the morphological segregation of these taxa.

T and B cell status in bronchiolitis and bronchial asthma.

Immunologic status of 43 children, 13 with bronchiolitis and 30 with bronchial asthma was studied, and compared with 10 infants and 16 healthy children of respective control groups. Humoral immunity was assessed by absolute eosinophil count and B cell count (EAC rosette method) and cellular immunity by T cell count (E rosette method) and DNCB skin test. B cell subset of lymphocytes were raised in both the study groups but associated significant eosinophilia was seen only in bronchial asthma. The study demonstrated significantly lower mean T cell count and depressed DNCB reactivity in children of bronchial asthma. Children with bronchiolitis too had significantly lower mean T cell count. Thus both humoral and cellular immunity were altered in children with bronchial asthma and bronchiolitis.