Tertiary Origin and Pleistocene Diversification of Dragon Blood Tree (Dracaena cambodiana-Asparagaceae) Populations in the Asian Tropical Forests

Background

The origin of extraordinarily rich biodiversity in tropical forests is often attributed to evolution under stable climatic conditions over a long period or to climatic fluctuations during the recent Quaternary period. Here, we test these two hypotheses using Dracaena cambodiana, a plant species distributed in paleotropical forests.

Methods

We analyzed nucleotide sequence data of two chloroplast DNA (cpDNA: atpB-rbcL and trnD-trnT) regions and genotype data of six nuclear microsatellites from 15 populations (140 and 363 individuals, respectively) distributed in Indochina Peninsular and Hainan Island to infer the patterns of genetic diversity and phylogeographic structure. The population bottleneck and genetic drift were estimated based upon nuclear microsatellites data using the software programs BOTTLENECK and 2MOD. The lineage divergence times and past population dynamics based on cpDNA data were estimated using coalescent-based isolation-with-migration (IMa) and BEAST software programs.

Results

A significant phylogeographic structure (N _ST = 0.876, G _ST = 0.796, F _ST-SSR =0.329, R _ST =0.449; N _ST>G _ST, R _ST>F _ST-SSR, P<0.05) and genetic differentiation among populations were detected. Bottleneck analyses and Bayesian skyline plot suggested recent population reduction. The cpDNA haplotype network revealed the ancestral populations from the southern Indochina region expanded to northward. The most recent ancestor divergence time of D. cambodiana dated back to the Tertiary era and rapid diversification of terminal lineages corresponded to the Quaternary period.

Conclusions

The results indicated that the present distribution of genetic diversity in D. cambodiana was an outcome of Tertiary dispersal and rapid divergence during the Quaternary period under limited gene flow influenced by the uplift of Himalayan-Tibetan Plateau and Quaternary climatic fluctuations respectively. Evolutionary processes, such as extinction-recolonization during the Pleistocene may have contributed to the fast diversification in D. cambodiana.     

Decreased Extracellular Adenosine Levels Lead to Loss of Hypoxia-Induced Neuroprotection after Repeated Episodes of Exposure to Hypoxia

Achieving a prolonged neuroprotective state following transient ischemic attacks (TIAs) is likely to effectively reduce the brain damage and neurological dysfunction associated with recurrent stroke. HPC is a phenomenon in which advanced exposure to mild hypoxia reduces the stroke volume produced by a subsequent TIA. However, this neuroprotection is not long-lasting, with the effects reaching a peak after 3 days. Therefore, in this study, we investigated the use of multiple episodes of hypoxic exposure at different time intervals to induce longer-term protection in a mouse stroke model. C57BL/6 mice were subjected to different hypoxic preconditioning protocols: a single episode of HPC or five identical episodes at intervals of 3 days (E3d HPC) or 6 days (E6d HPC). Three days after the last hypoxic exposure, temporary middle cerebral artery occlusion (MCAO) was induced. The effects of these HPC protocols on hypoxia-inducible factor (HIF) regulated gene mRNA expression were measured by quantitative PCR. Changes in extracellular adenosine concentrations, known to exert neuroprotective effects, were also measured using in vivo microdialysis and high pressure liquid chromatography (HPLC). Neuroprotection was provided by E6d HPC but not E3d HPC. HIF-regulated target gene expression increased significantly following all HPC protocols. However, E3d HPC significantly decreased extracellular adenosine and reduced cerebral blood flow in the ischemic region with upregulated expression of the adenosine transporter, equilibrative nucleoside transporter 1 (ENT1). An ENT1 inhibitor, propentofylline increased the cerebral blood flow and re-established neuroprotection in E3d HPC. Adenosine receptor specific antagonists showed that adenosine mainly through A1 receptor mediates HPC induced neuroprotection. Our data indicate that cooperation of HIF-regulated genes and extracellular adenosine is necessary for HPC-induced neuroprotection.     

Comparison of HER2 and Phospho-HER2 Expression between Biopsy and Resected Breast Cancer Specimens Using a Quantitative Assessment Method

Background

HER2/Neu (ErbB-2) overexpression, which occurs in 15–20% of breast cancer cases, is associated with better response to treatment with the drug trastuzumab. PhosphoHER2 (pHER2) has been evaluated for prediction of response to trastuzumab. Both markers are heterogeneously detected and are potentially subject to loss as a consequence of delayed time to fixation. Here, we quantitatively assess both markers in core needle biopsies (CNBs) and matched tumor resections to assess concordance between the core and the resection and between HER2 and pHER2.

Methods

A selected retrospective collection of archival breast cancer cases yielded 67 cases with both core and resection specimens. Both HER2 and pTyr¹²⁴⁸HER2 were analyzed by the AQUA® method of quantitative immunofluorescence on each specimen pair.

Results

Both HER2 immunoreactivity (P<0.0001) and pTyr¹²⁴⁸HER2 immunoreactivity (P<0.0001) were lower in resections relative to CNB specimens. However, clinical implications of this change may not be evident since no case changed from 3+ (CNB) to negative (resection). Assessment of pTyr¹²⁴⁸HER2 showed no direct correlation with HER2 in either CNB or resection specimens.

Conclusions

The data suggest that measurement of both HER2 and phospho- Tyr¹²⁴⁸HER2, in formalin-fixed tissue by immunological methods is significantly affected by pre-analytic variables. The current study warrants the adequate handling of resected specimens for the reproducible evaluation of HER2 and pHER2. The level of pTyr¹²⁴⁸HER2, was not correlated to total HER2 protein. Further studies are required to determine the significance of these observations with respect to response to HER2 directed therapies.     

Oral and Craniofacial Manifestations and Two Novel Missense Mutations of the NTRK1 Gene Identified in the Patient with Congenital Insensitivity to Pain with Anhidrosis

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare inherited disorder of the peripheral nervous system resulting from mutations in neurotrophic tyrosine kinase receptor 1 gene (NTRK1), which encodes the high-affinity nerve growth factor receptor TRKA. Here, we investigated the oral and craniofacial manifestations of a Chinese patient affected by autosomal-recessive CIPA and identified compound heterozygosity in the NTRK1 gene. The affected boy has multisystemic disorder with lack of reaction to pain stimuli accompanied by self-mutilation behavior, the inability to sweat leading to defective thermoregulation, and mental retardation. Oral and craniofacial manifestations included a large number of missing teeth, nasal malformation, submucous cleft palate, severe soft tissue injuries, dental caries and malocclusion. Histopathological evaluation of the skin sample revealed severe peripheral nerve fiber loss as well as mild loss and absent innervation of sweat glands. Ultrastructural and morphometric studies of a shed tooth revealed dental abnormalities, including hypomineralization, dentin hypoplasia, cementogenesis defects and a dysplastic periodontal ligament. Genetic analysis revealed a compound heterozygosity- c.1561T>C and c.2057G>A in the NTRK1 gene. This report extends the spectrum of NTRK1 mutations observed in patients diagnosed with CIPA and provides additional insight for clinical and molecular diagnosis.     

乏情和发情初产母猪下丘脑–垂体–卵巢轴中lincRNAs表达谱比较分析

初产母猪断奶后能否正常发情对养猪生产影响重大,也是初产母猪被淘汰的主要原因。本研究以乏情和发情初产母猪为研究对象,首次利用RNA-seq技术对其下丘脑-垂体-卵巢轴中的基因间长链非编码RNAs(long intergenic noncoding RNAs,lincRNAs)进行筛选比较,得到lincRNAs的表达图谱,并对其特征和功能进行了初步分析。结果显示,在乏情和发情初产母猪下丘脑–垂体–卵巢轴中鉴定得到3519个lincRNAs,以发情组为对照共有17个lincRNAs存在差异表达,其中12个表达上调,5个表达下调(FC≥2,P<0.05)。选择4个差异表达的lincRNAs经qRT-PCR验证,其表达水平与测序结果基本一致。对这17个差异表达的lincRNAs进行GO分析、KEGG通路分析及lincRNA-mRNA共表达网络分析,发现这些lincRNAs主要与猪卵母细胞减数分裂成熟、卵巢细胞分化及颗粒细胞凋亡等生殖活动相关。本研究结果丰富了猪lincRNAs数据资源,为进一步深入研究初产母猪的生殖机能提供了理论依据。     

Dietary adaptations and palaeoecology of Lophialetidae (Mammalia,Tapiroidea) from the Eocene of the Erlian Basin,China: combined evidence from mesowear and stable isotope analyses

Lophialetidae is an extinct group of endemic Asiatic tapiroids that are widely distributed in the Eocene sediments of Asia. Schlosseria magister and Lophialetes expeditus are the most abundant species in this family. However, their dietary and ecological characteristics are largely unknown. For the first time, we reconstruct the palaeodiet and habitat of these two lophialetids using a combination of mesowear and stable carbon isotope analysis of fossil teeth excavated from the Erlian Basin, China. Mesowear analysis (n = 141) suggests that the dietary structure of S. magister and L. expeditus shifted from less to more abrasive diets from ~52 to ~42 Ma. Stable carbon isotope analysis (n = 137) suggests that the habitats of S. magister and L. expeditus became drier and/or more open through time. The dietary shifts of the two lophialetids are consistent with evident changes in habitat. The changes in the diet and habitat were probably related to global climate change during that time period. The gradual drop in global temperatures during the early–middle Eocene led to a drier and more open terrestrial ecosystem in the Erlian Basin, probably resulting in changes in floral composition of the environment inhabited by S. magister and L. expeditus. Hence, herbivores highly susceptible to vegetation modification had to develop new resource exploitation strategies to adapt to these changes. Schlosseria magister, considered to be the sister-group of L. expeditus and with a low level of ecological flexibility, was unable to adapt to the habitat changes finally becoming extinct at ~45 Ma.