Phylogeography of the world's tallest angiosperm, Eucalyptus regnans: evidence for multiple isolated Quaternary refugia

Aim There is a need for more Southern Hemisphere phylogeography studies, particularly in Australia, where, unlike much of Europe and North America, ice sheet cover was not extensive during the Last Glacial Maximum (LGM). This study examines the phylogeography of the south‐east Australian montane tree species Eucalyptus regnans. The work aimed to identify any major evolutionary divergences or disjunctions across the species’ range and to examine genetic signatures of past range contraction and expansion events. Location South‐eastern mainland Australia and the large island of Tasmania. Methods We determined the chloroplast DNA haplotypes of 410 E. regnans individuals (41 locations) based on five chloroplast microsatellites. Genetic structure was examined using analysis of molecular variance (AMOVA), and a statistical parsimony tree was constructed showing the number of nucleotide differences between haplotypes. Geographic structure in population genetic diversity was examined with the calculation of diversity parameters for the mainland and Tasmania, and for 10 regions. Regional analysis was conducted to test hypotheses that some areas within the species’ current distribution were refugia during the LGM and that other areas have been recolonized by E. regnans since the LGM. Results Among the 410 E. regnans individuals analysed, 31 haplotypes were identified. The statistical parsimony tree shows that haplotypes divided into two distinct groups corresponding to mainland Australia and Tasmania. The distribution of haplotypes across the range of E. regnans shows strong geographic patterns, with many populations and even certain regions in which a particular haplotype is fixed. Many locations had unique haplotypes, particularly those in East Gippsland in south‐eastern mainland Australia, north‐eastern Tasmania and south‐eastern Tasmania. Higher haplotype diversity was found in putative refugia, and lower haplotype diversity in areas likely to have been recolonized since the LGM. Main conclusions The data are consistent with the long‐term persistence of E. regnans in many regions and the recent recolonization of other regions, such as the Central Highlands of south‐eastern mainland Australia. This suggests that, in spite of the narrow ecological tolerances of the species and the harsh environmental conditions during the LGM, E. regnans was able to persist locally or contracted to many near‐coastal refugia, maintaining a diverse genetic structure.     

An analysis of travel costs on transport of load and nest building in golden hamster

We investigated the effects of travel costs on transporting nest material and nest-building activity in golden hamsters. Nest-deprived animals were submitted to run alleys 30, 90 and 180 cm long to access a source containing paper strips as nest material (Experiment 1) or were submitted to the same travel costs in 24-h experimental sessions (Experiment 2). We noted that increased travel costs were related to a decreased number of trips to the source, larger amounts (cm(2)) of nest material transported per trip (although total loads also decreased in longer alleys), longer intervals between trips, and increased time spent at the source and in nest building activity. Foraging efficiency (i.e. size of load divided by the time spent at the source) decreased as a function of travel costs, and animals transported their loads in two fundamental ways: in 30-cm alleys, they simply used their mouth to pull the paper strips, but in 90- or 180-cm alleys they transported the loads in their cheek pouches. The animals were faster when returning to the home-cage and their running speed (cm/s) increased as a function of the length of the alley, showing that animals are under different environmental pressures when searching for resources and subsequently running back with the load to the nest. Both male and female subjects were sensitive to travel costs, but males engaged in nest building activity more promptly and exhibited higher mean performances in most measures. We conclude that nest material is a good reinforcer, and our major results are in accordance with the predictions of microeconomic and optimal foraging theories.     

Vertical transmission rates for HIV in the British Isles: estimates based on surveillance data

ObjectiveTo estimate and interpret time trends in vertical transmission rates for HIV using data from national obstetric and paediatric surveillance registers.DesignProspective study of HIV infected women reported through obstetric surveillance. HIV infection status of the child and onset of AIDS were reported through paediatric surveillance. Rates of vertical transmission and progression to AIDS rate were estimated by methods that take account of incomplete follow up of children with indeterminate infection status and delay in AIDS reporting.SettingBritish Isles.SubjectsPregnant women infected with HIV whose infection was diagnosed before delivery, and their babies.ResultsBy January 1999, 800 children born to diagnosed HIV infected women who had not breast fed had been reported. Vertical transmission rates rose to 19.6% (95% confidence interval 8.0% to 32.5%) in 1993 before falling to 2.2% (0% to 7.8%) in 1998. Between 1995 and 1998 use of antiretroviral treatment increased significantly each year, reaching 97% of live births in 1998. The rate of elective caesarean section remained constant, at around 40%, up to 1997 but increased to 62% in 1998. Caesarean section and antiretroviral treatment together were estimated to reduce risk of transmission from 31.6% (13.6% to 52.2%) to 4.2% (0.8% to 8.5%). The proportion of infected children developing AIDS in the first 6 months fell from 17.7% (6.8% to 30.8%) before 1994 to 7.2% (0% to 15.7%) after, coinciding with increased use of prophylaxis against Pneumocystis carinii pneumonia.ConclusionsIn the British Isles both HIV related morbidity and vertical transmission are being reduced through increased use of interventions.

Key messages

• Reliable estimates of HIV vertical transmission rates can be derived from surveillance data
• Infected pregnant women are increasingly taking up elective caesarean section and antiretroviral treatment to reduce the risk of transmitting HIV to their babies
• Vertical transmission rates have fallen greatly over the past four years and progression to AIDS among infected children may also have slowed
• These benefits can occur only if infected women are diagnosed before or during pregnancy

     

Sexual differences in caudal morphology and its relation to tail autotomy in lacertid lizards

We hypothesized that the presence of the forked hemipenes, and associated musculature, at the base of the tail in male lizards should constrain the capacity to autotomize the tail. Thus, this hypothesis predicts that the non-autotomous base of the tail should be longer in male than in female lizards. We tested this hypothesis in four species oflacertid lizards. Males have on average one to two non-autotomous vertebrae more than females, and the sexual difference in length of the non-autotomous tail base remains constant over the entire body size range. In addition, the first functional autotomy plane in males is usually located on, or is distal to, the vertebrae from which two hemipenial muscles take origin. These observations support the view that functional demands of the male intromittent organs impose constraints on the abilities of tail autotomy. In a natural population of Lacerta vivipara , the proportion of tail breaks that occurred at very short distances from the base was highest in females, indicating that the small sexual difference in length of the non-autotomous tail part is of functional significance. Total length of the tail was largest in males. This can be interpreted as a compensation for the decline in autotomy capacities at the tail base, such that the length of the autotomous part remains similar in both sexes.     

Smoking status and anti-inflammatory macrophages in bronchoalveolar lavage and induced sputum in COPD

Background

Macrophages have been implicated in the pathogenesis of COPD. M1 and M2 macrophages constitute subpopulations displaying pro- and anti-inflammatory properties. We hypothesized that smoking cessation affects macrophage heterogeneity in the lung of patients with COPD. Our aim was to study macrophage heterogeneity using the M2-marker CD163 and selected pro- and anti-inflammatory mediators in bronchoalveolar lavage (BAL) fluid and induced sputum from current smokers and ex-smokers with COPD.

Methods

114 COPD patients (72 current smokers; 42 ex-smokers, median smoking cessation 3.5 years) were studied cross-sectionally and underwent sputum induction (M/F 99/15, age 62 ± 8 [mean ± SD] years, 42 (31-55) [median (range)] packyears, post-bronchodilator FEV₁ 63 ± 9% predicted, no steroids past 6 months). BAL was collected from 71 patients. CD163⁺ macrophages were quantified in BAL and sputum cytospins. Pro- and anti-inflammatory mediators were measured in BAL and sputum supernatants.

Results

Ex-smokers with COPD had a higher percentage, but lower number of CD163⁺ macrophages in BAL than current smokers (83.5% and 68.0%, p = 0.04; 5.6 and 20.1 ×10⁴/ml, p = 0.001 respectively). The percentage CD163⁺ M2 macrophages was higher in BAL compared to sputum (74.0% and 30.3%, p < 0.001). BAL M-CSF levels were higher in smokers than ex-smokers (571 pg/ml and 150 pg/ml, p = 0.001) and correlated with the number of CD163⁺ BAL macrophages (Rs = 0.38, p = 0.003). No significant differences were found between smokers and ex-smokers in the levels of pro-inflammatory (IL-6 and IL-8), and anti-inflammatory (elafin, and Secretory Leukocyte Protease Inhibitor [SLPI]) mediators in BAL and sputum.

Conclusions

Our data suggest that smoking cessation partially changes the macrophage polarization in vivo in the periphery of the lung towards an anti-inflammatory phenotype, which is not accompanied by a decrease in inflammatory parameters.     

QTL analysis for ascochyta blight resistance in an intraspecific population of chickpea (<Emphasis Type="Italic">Cicer arietinum</Emphasis> L.)

In both controlled environment and the field, six QTLs for ascochyta blight resistance were identified in three regions of the genome of an intraspecific population of chickpea using the IDS and AUDPC disease scoring systems. One QTL-region was detected from both environments, whereas the other two regions were detected from each environment. All the QTL-regions were significantly associated with ascochyta blight resistance using either of the disease scoring systems. The QTLs were verified by multiple interval mapping, and a two-QTL genetic model with considerable epistasis was established for both environments. The major QTLs generally showed additive gene action, as well as dominance inter-locus interaction in the multiple genetic model. All the QTLs were mapped near a RGA marker. The major QTLs were located on LG III, which was mapped with five different types of RGA markers. A CLRR-RGA marker and a STMS marker flanked QTL 6 for controlled environment resistance at 0.06 and 0.04 cM, respectively. Other STMS markers flanked QTL 1 for field resistance at a 5.6 cM interval. After validation, these flanking markers may be used in marker-assisted selection to breed for elite chickpea cultivars with durable resistance to ascochyta blight. The tight linkage of RGA markers to the major QTL on LG III will allow map-based cloning of the underlying resistance genes.Communicated by P. Langridge     

Maturation of embryonic chick liver delta-aminolevulinate synthase: precursor pools and regulation by intra-cellularly produced heme

1. Immunoblot analyses were carried out to determine the relative distributions of delta-aminolevulinate synthase (ALA synthase) in mitochondrial and cytosol fractions prepared from embryos at different times after injections with allylisopropylacetamide (AIA). 2. The results indicated that the molecular mass of mature ALA synthase (Mr 65,000) increased with time in mitochondria. 3. At no time was the precursor form (Mr 75,000) of the enzyme detected either in mitochondria or in the cytosol. 4. In primary cultures of hepatocytes, where the increased production of ALA synthase had been induced with AIA, addition of delta-aminolevulinic acid (ALA) and Fe2(SO4)3 into the culture medium completely blocked the processing of the precursor form of the enzyme. 5. On the other hand, the addition of ALA together with deferoxamine mesylate into the medium had no detectable effect on the maturation of ALA synthase in the hepatocytes. 6. The results indicated: first, that upon induction of porphyria the pools of pre-ALA synthase in liver are relatively low in chick embryos when compared with those in other organisms; and second, that increased heme production by the hepatocytes caused the inhibition of processing of the precursor form of ALA synthase.