Biological responses to extreme weather events are detectable but difficult to formally attribute to anthropogenic climate change.

As the frequency and intensity of extreme events such as droughts, heatwaves and floods have increased over recent decades, more extreme biological responses are being reported, and there is widespread interest in attributing such responses to anthropogenic climate change. However, the formal detection and attribution of biological responses to climate change is associated with many challenges. We illustrate these challenges with data from the Elbe River floodplain, Germany. Using community turnover and stability indices, we show that responses in plant, carabid and mollusc communities are detectable following extreme events. Community composition and species dominance changed following the extreme flood and summer heatwave of 2002/2003 (all taxa); the 2006 flood and heatwave (molluscs); and after the recurring floods and heatwave of 2010 and the 2013 flood (plants). Nevertheless, our ability to attribute these responses to anthropogenic climate change is limited by high natural variability in climate and biological data; lack of long-term data and replication, and the effects of multiple events. Without better understanding of the mechanisms behind change and the interactions, feedbacks and potentially lagged responses, multiple-driver attribution is unlikely. We discuss whether formal detection and/or attribution is necessary and suggest ways in which understanding of biological responses to extreme events could progress.

Complete Genome Sequence of Anaeromyxobacter sp. Fw109-5, an Anaerobic, Metal-Reducing Bacterium Isolated from a Contaminated Subsurface Environment.

We report the genome sequence of Anaeromyxobacter sp. Fw109-5, isolated from nitrate- and uranium-contaminated subsurface sediment of the Oak Ridge Integrated Field-Scale Subsurface Research Challenge (IFC) site, Oak Ridge Reservation, TN. The bacterium's genome sequence will elucidate its physiological potential in subsurface sediments undergoing in situ uranium bioremediation and natural attenuation.

Prenatal diagnosis. Chorionic villus biopsy.

Of all the methods of prenatal diagnosis the implications of chorionic villus biopsy are the most far-reaching and potentially controversial. DNA analysis of the fetus is now possible at the end of the first trimester and it can only be a matter of time before our knowledge of genetic disease markers makes the perfect race a feasibility.

Assessment of a transcervical aspiration technique for chorionic villus biopsy in the first trimester of pregnancy.

A cannula attached to a syringe was passed through the cervical canal into the uterine cavity in an attempt to aspirate chorionic villi just before termination of a first trimester pregnancy in 82 patients. Chorionic villi were obtained from 40% of these patients. In view of the value of this technique for the first trimester diagnosis of genetic disorder, development of the technique and further trials of transcervical aspiration of chorionic villi would seem warranted.

Trophoblast sampling in early pregnancy. Culture of rapidly dividing cells from immature placental villi.

Trophoblast was obtained by ordinary suction curettage and by transcervical aspiration with a medicut cannula from women having a therapeutic abortion in the first trimester of pregnancy. The decidual tissue which is invariably attached to early placental villi was separated and pure cultures obtained from the trophoblast layers and from the mesenchymal core of placental villi. Cytotrophoblast had a very limited life span in tissue culture, whereas mesenchymal cells grew rapidly and could be used for antenatal diagnosis.

Extraction of DNA from amniotic fluid cells for the early prenatal diagnosis of genetic disease.

Ten-ml samples of amniotic fluid were taken from pregnancies being terminated at 8-14 weeks' gestation. DNA was extracted from the amniotic cells by sequential centrifugation and analysed using the polymerase chain reaction (PCR). Fifteen samples were analysed for evidence of maternal contamination using Mfd5 oligonucleotide primers for repeat polymorphisms. Ten amniotic fluid samples were tested for the Delta-F508 deletion characteristic of cystic fibrosis to demonstrate a diagnostic application for the technique. In each case, DNA extracted from fetal tissue from the same pregnancy was included in the controls. In 14 of the 15 cases tested with the Mfd5 primers, both the amniotic fluid DNA and the fetal DNA showed no evidence of contaminating DNA. In one case, neither the amniotic fluid cells nor the fetal cells yielded results. In nine of the ten cases tested with the Delta-F508 primers, the amniotic fluid cell DNA provided accurate information about the genetic status of the fetus; in the tenth, the fetal DNA failed to amplify. The results indicate that adequate DNA can be extracted from amniotic fluid from 8 weeks' gestation onward and these samples are suitable for prenatal diagnosis using PCR.

Early amniocentesis at 11-14 weeks' gestation for the diagnosis of fetal chromosomal abnormality--a clinical evaluation.

Early amniocentesis between 11 and 14 weeks' gestation was offered to 110 women at risk of a chromosomally abnormal fetus due to maternal age. Four were found to be unsuitable for the procedure, and 106 early amniocenteses were performed. In 102 cases, clear amniotic fluid was obtained with a single tap. There were two dry taps and two bloodstained taps; sampling was repeated in three of these cases before 15 weeks. In the fourth case, placental biopsy was performed at 16 weeks. Thus, we were able to obtain a satisfactory sample in all but three cases (2.8 per cent). Karyotyping of cells harvested from the early amniotic fluid samples was successful in all the 105 cases. Cell culture from the initial samples revealed a normal karyotype in 99 cases, two balanced translocations, two tetraploid karyotypes, and two cases of pseudomosaicism. Of the 105 pregnancies successfully sampled, there have been two losses to date (1.8 per cent). Two further patients presented with premature rupture of membranes, both pregnancies having successful outcomes. Sixty-two babies have delivered to date, with four congenital anomalies. There were no respiratory problems. Twenty-nine pregnancies are continuing without known complications, and details are not yet available on the remaining 12. The results indicate that early amniocentesis may replace the traditional test at 15-17 weeks.

Cytogenetic studies of amniotic fluid taken before the 15th week of pregnancy for earlier prenatal diagnosis: a report of 114 consecutive cases.

One hundred and fourteen samples of amniotic fluid taken before 15 weeks of gestation were cultured for cytogenetic studies. The results of culturing these early amniotic fluid (EAF) samples were compared with the results of culturing 114 standard amniotic fluid (SAF) samples taken after 15 weeks of gestation matched for maternal age and received in the laboratory within the same week. Cell culture was successful in all 114 of the EAF samples and in 111 SAF samples. There was no significant difference in the days to harvesting and days to reporting in the two groups. Three samples of SAF failed to grow and two EAF samples produced tetraploid karyotypes, so that in these five cases amniocentesis had to be repeated. These problems were attributed to toxicity of a fungicide used in the culture medium. Pseudo-mosaicism was noted in two EAF samples and one SAF sample; and maternal cell contamination was noted in one EAF and one SAF sample. Thus, culturing and karyotyping cells harvested from EAF and SAF are similar, indicating that EAF samples from 12-14-week pregnancies could be used for prenatal diagnosis.