Effects of a transient oxic period on mineralization of organic matter to CH4 and CO2 in anoxic peat incubations

Rates of organic matter mineralization in peatlands, and hence production of the greenhouse gases CH₄ and CO₂, are highly dependent on the distribution of oxygen in the peat. Using laboratory incubations of peat, we investigated the sensitivity of the anoxic production of CH₄ and CO₂ to a transient oxic period of a few weeks’ duration. Production rates during 3 successive anoxic periods were compared with rates in samples incubated in the presence of oxygen during the second period. In surface peat (5–10‐cm depth), with an initially high level of CH₄ production, oxic conditions during period 2 did not result in a lower potential CH₄ production rate during period 3, although production was delayed ～1 week. In permanently anoxic, deep peat (50–55‐cm depth) with a comparatively low initial production of CH₄, oxic conditions during period 2 resulted in zero production of CH₄ during period 3. Thus, the methanogens in surface peal—but not in deep peat—remained viable after several weeks of oxic conditions. In contrast to CH₄ production, the oxic period had a negligible effect on anoxic CO₂ production during period 3, in surface as well as deep peat. In both surface and deep peat, CO₂ production was several times higher under oxic than under anoxic conditions. However, for the first 2 weeks of oxic conditions, CO₂ production in the deep peat was very low. Still, deep peat obviously contained facultative microorganisms that, after a relatively short period, were able to maintain a considerably higher rate of organic matter mineralization under oxic than under anoxic conditions.     

First record of the Atlantic bumper Chloroscombrus chrysurus (Teleostei: Carangidae) in the Mediterranean Sea

In December 1997, one specimen of the Atlantic bumper, Chloroscombrus chrysurus was recorded for the first time in the Mediterranean Sea, off Almuñécar (Granada, Spain: 36° 43′ 26″ N; 3° 41′ 39″ W). This species probably entered the Mediterranean Sea via the Strait of Gibraltar.     

Dispersal,fragmentation, and isolation shape the phylogeography of the European lineages of Polyommatus (Agrodiaetus) ripartii (Lepidoptera: Lycaenidae)

Polyommatus ripartii is a biogeographically and taxonomically poorly understood species of butterfly with a scattered distribution in Europe. Recently, it has been shown that this species includes several European endemic and localized taxa (galloi, exuberans, agenjoi) that were previously considered species and even protected, a result that poses further questions about the processes that led to its current distribution. We analysed mitochondrial DNA and the morphology of P. ripartii specimens to study the phylogeography of European populations. Three genetically differentiated but apparently synmorphic lineages occur in Europe that could be considered evolutionarily significant units for conservation. Their strongly fragmented and counterintuitive distribution seems to be the result of multiple range expansions and contractions along Pleistocene climatic oscillations. Remarkably, based on the 79 specimens studied, these genetic lineages do not seem to extensively coexist in the distributional mosaic, a phenomenon most evident in the Iberian Peninsula. One of the important gaps in the European distribution of P. ripartii is reduced by the discovery of new Croatian populations, which also facilitate a better understanding of the biogeography of the species. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 817‐829.     

Development of a new bioprocess scheme using frozen seed train intermediates to initiate CHO cell culture manufacturing campaigns

Agility to schedule and execute cell culture manufacturing campaigns quickly in a multi‐product facility will play a key role in meeting the growing demand for therapeutic proteins. In an effort to shorten campaign timelines, maximize plant flexibility and resource utilization, we investigated the initiation of cell culture manufacturing campaigns using CHO cells cryopreserved in large volume bags in place of the seed train process flows that are conventionally used in cell culture manufacturing. This approach, termed FASTEC (Frozen Accelerated Seed Train for Execution of a Campaign), involves cultivating cells to high density in a perfusion bioreactor, and cryopreserving cells in multiple disposable bags. Each run for a manufacturing campaign would then come from a thaw of one or more of these cryopreserved bags. This article reviews the development and optimization of individual steps of the FASTEC bioprocess scheme: scaling up cells to greater than 70 × 10⁶ cells/mL and freezing in bags with an optimized controlled rate freezing protocol and using a customized rack configuration. Flow cytometry analysis was also employed to understand the recovery of CHO cells following cryopreservation. Extensive development data were gathered to ensure that the quantity and quality of the drug manufactured using the FASTEC bioprocess scheme was acceptable compared to the conventional seed train process flow. The result of offering comparable manufacturing options offers flexibility to the cell culture manufacturing network. Biotechnol. Bioeng. 2013; 110: 1376–1385. © 2012 Wiley Periodicals, Inc.     

Exploring prehistory in the North American southwest with mitochondrial DNA diversity exhibited by Yumans and Athapaskans

A recent study of mitochondrial DNA variation in Native American populations from the American Southwest detected signatures of a population expansion of subhaplogroup B2a, dated to 2,105 years before present (99.5% confidence interval, 1,273–3,773 YBP), following the introduction and intensification of maize agriculture in the region. Only one Yuman group and no Athapaskan speakers were analyzed in previous studies. Here we report mtDNA haplogroup and hypervariable region (HVR I, and II) sequence data from 263 extant Yuman speakers, representing the major branches of the Yuman language family, in addition to the Western Apache (Athapaskan) to further investigate the demographic context and geographic extent of this expansion. Data presented indicate that the expansion of B2a is only slightly older [2,410 YBP (99.5% CI: 1,458–4,320 YBP)] than previously estimated and not significantly. Despite large confidence intervals there are implications for the origin and expansion of the Yuman language family. Cultural transformations due to the inundation and draining of Lake Cahuilla may explain in part the frequencies of this lineage among the Kumeyaay and other Yuman and Takic groups in Southern California. This may have been the result of group fissions and fusions followed by migration and interaction that included expanded trade networks and intermarriage among Yuman speakers. In addition, a series of in‐situ genetic bottlenecks is proposed to have occurred among the Western Apache leading to increasing homogeneity within haplogroup A, culminating in an admixture event with the Yavapai. Am J Phys Anthropol 150:618–631, 2013. © 2013 Wiley Periodicals, Inc.     

Late‐glacial recolonization and phylogeography of European red deer (Cervus elaphus L.)

The Pleistocene was an epoch of extreme climatic and environmental changes. How individual species responded to the repeated cycles of warm and cold stages is a major topic of debate. For the European fauna and flora, an expansion–contraction model has been suggested, whereby temperate species were restricted to southern refugia during glacial times and expanded northwards during interglacials, including the present interglacial (Holocene). Here, we test this model on the red deer (Cervus elaphus) a large and highly mobile herbivore, using both modern and ancient mitochondrial DNA from the entire European range of the species over the last c. 40 000 years. Our results indicate that this species was sensitive to the effects of climate change. Prior to the Last Glacial Maximum (LGM) haplogroups restricted today to South‐East Europe and Western Asia reached as far west as the UK. During the LGM, red deer was mainly restricted to southern refugia, in Iberia, the Balkans and possibly in Italy and South‐Western Asia. At the end of the LGM, red deer expanded from the Iberian refugium, to Central and Northern Europe, including the UK, Belgium, Scandinavia, Germany, Poland and Belarus. Ancient DNA data cannot rule out refugial survival of red deer in North‐West Europe through the LGM. Had such deer survived, though, they were replaced by deer migrating from Iberia at the end of the glacial. The Balkans served as a separate LGM refugium and were probably connected to Western Asia with genetic exchange between the two areas.     

基于林业清查资料的桂西北植被碳空间分布及其变化特征

基于2005-2010年林业资源清查数据,采用材积源生物量法,运用地理信息系统技术,估算和分析了桂西北植被碳密度及其储量的空间分布及其变化。结果显示:(1) 研究区域从2005年到2010年呈现碳汇变化趋势,植被碳储量由4.19×10⁴t增加到4.27×10⁴t(增幅为1.84%),植被碳密度从29.04t/hm²增加到29.57 t/hm²。(2) 从治理措施、林种起源方式及林种类型来看,自然保护区的植被碳密度最大,超过40 t/hm²。2005-2010年,人工植苗、直播、飞播和萌生方式植被碳密度增加,退耕还林工程的植被碳密度均呈明显增长(增加3.00 t/hm²),所有林种碳密度都呈不同程度的增长。 (3)植被碳密度空间分布上,大致表现为西部高、中东部低,北部高、南部低。西部区植被碳密度均值超过40 t/hm²,中东部区植被碳密度均值低于25 t/hm²。植被碳密度变化在空间分布上表现为无论是非喀斯特区还是喀斯特区的植被碳密度都有增长趋势,其中有7个县市植被碳密度升级为更高等级。研究表明,随着退耕还林、生态移民等治理措施的实施,区域植被碳密度显著增加,生态环境好转。     

植物器官大小相关基因研究进展

器官大小是植物形态的一个重要特征,而且具有严格的种属特异性。植物器官大小虽然受到外在的环境因素（如光照、营养等）的影响,但它由内在特有的细胞数目和细胞大小决定。许多通过转录调节、蛋白合成、激素调节或松弛细胞壁等途径作用于植物细胞繁殖和/或细胞扩张的基因已经被鉴定,它们的过表达或缺失表达能促进植物器官大小和加快植物生长。尽管如此,这些基因通过相对独立的途径起作用,在植物中难以阐明一个相对整合的器官大小基因调控网络,这也是该研究领域的亟待需要解决的问题。目前,一些器官大小相关基因已经应用农作物育种,并培育出显著增大的农作物品种,这也证实了利用器官大小基因进行植物品种选育的可行性。因此,通过研究药用植物器官大小的基因,人为地在分子水平上有目的的调控器官的大小和形态,是缓解当前许多药用植物面临的资源紧缺、枯竭濒危困境的可考虑途径之一。     

Contributions to the Flora of Spitsbergen,especially of Red bay,from the Collections of W. S. Bruce,F.R.S.G.S., Naturalist to the Prince of Monaco's Expeditions of 1898 and 1899

Background: Prescribed burning in peatlands is controversial due to concerns over damage to their ecological functioning, particularly regarding their key genus Sphagnum. However, empirical evidence is scarce.

Aims: The aim of the article is to quantify Sphagnum recovery following prescribed burns.

Methods: We completed nine fires at a raised bog in Scotland, achieving a range of fire severities by simulating drought in some plots. We measured Sphagnum cover and chlorophyll fluorescence F_v/F_m ratio (an estimate of photosynthetic capacity) up to 36 months post-fire.

Results: Cover of dominant Sphagnum capillifolium was similar in unburnt and burnt plots, likely due to its high moisture content which prevented combustion. Burning decreased S. capillifolium F_v/F_m 5 months after fire from 0.67 in unburnt plots to 0.44 in low fire severity plots and 0.24 in higher fire severity (drought) plots. After 22 months, F_v/F_m in burnt plots showed a healthy photosynthetic capacity of 0.76 and no differences between severity treatments. Other Sphagnum species showed similar post-fire recovery though their low overall abundance precluded formal statistical analysis.

Conclusions: S. capillifolium is resilient to low–moderate fire severities and the same may be true for a number of other species. This suggests that carefully applied managed burning can be compatible with the conservation of peatland ecosystem function.