Commentary

Recently rediscovered type material referred to Muensteria Stern‐berg confirms that in its original (paleobotanical) definition this genus is too heterogenous to be useful in ichnotaxonomy. It contains plant remains, a coprolite string, and trace fossils. Some corrections concerning appearance of the analyzed specimens are introduced.     

Lipid and DNA Evidence of Dominance of Planktonic Archaea Preserved in Sediments of the South China Sea: Insight for Application of the TEX86 Proxy in an Unstable Marine Sediment Environment

The marine planktonic archaea are dominated by Thaumarchaeotal Marine Group I, which is characterized by the lipid biomarker thaumarchaeol. The marine benthic archaea are characterized by greater diversity of currently unknown species whose lipid biomarker signatures are uncertain. In this study, a sediment core from the northwestern part of the South China Sea (SCS) (water depth 1474 m) was analyzed using molecular DNA and lipid biomarker approaches. While 16S rRNA gene analysis showed changing archaeal community structures with sediment depth, this change had little impact on the fossil record of archaeal lipids that are characteristic of the planktonic community. As a result, the fossil archaeal lipids recorded paleo sea surface temperature of the SCS since the last glacial maxima by the TEX₈₆ proxy, which agreed generally with the winter temperature recorded by planktonic foraminiferas collected from the same area of the SCS that hosted mass-transported deposits. This suggests that this deep water deposit may have partially preserved paleoclimate record reflecting seasonal temperature variation in a near shore setting, which is in contrast to annual sea surface temperature or sub sea surface temperature variation recorded by TEX₈₆ in the open ocean.     

The cationic composition and pH in the moulting fluid of Porcellio scaber (Crustacea, Isopoda) during calcium carbonate deposit formation and resorption

Before moulting, terrestrial isopods resorb calcium carbonate (CaCO₃) from the posterior cuticle and store it in sternal deposits. These consist mainly of amorphous calcium carbonate (ACC) spherules that develop within the ecdysial space between the anterior sternal epithelium and the old cuticle. Ions that occur in the moulting fluid, including those required for mineral deposition, are transported from the hemolymph into the ecdysial space by the anterior sternal epithelial cells. The cationic composition of the moulting fluid probably affects mineral deposition and may provide information on the ion-transport activity of the sternal epithelial cells. This study presents the concentrations of inorganic cations within the moulting fluid of the anterior sternites during the late premoult and intramoult stages. The most abundant cation is Na⁺ followed by Mg²⁺, Ca²⁺ and K⁺. The concentrations of these ions do not change significantly between the stages whereas the mean pH changed from 8.2 to 6.9 units between mineral deposition in late premoult, and resorption in intramoult, respectively. Measurements of the transepithelial potential show that there is little driving force for passive movements of calcium across the anterior sternal epithelium. The results suggest a possible role of magnesium ions in ACC formation, and a contribution of pH changes to CaCO₃ precipitation and dissolution.     

Paleoceanographic shifts and global events recorded in late Pliocene shallow marine deposits (2.80–2.55 Ma) of the Sea of Japan

Fossil ostracod assemblages from the upper Pliocene Kuwae Formation of the Kurokawa area, Niigata Prefecture, central Japan were investigated to discern the high resolution paleoceanographic changes in the Sea of Japan during the transitional interval from a warm to a cold climate in the period from 2.80 to 2.55 Ma, dated previously from diatom and nannofossil datum horizons and magnetostratigraphy. The studied ostracod assemblages did not contain Tsushima Warm Core Current taxa known in the modern Sea of Japan, and most of them are cryophilic and circumpolar. The combinations of recognized fossil ostracod assemblages differ from the modern ones of the region, suggesting that the shallow water area was probably colder than that of today. The Kuwae Formation was deposited during several bathymetric fluctuations between upper bathyal and lower sublittoral zone. A large-scale shift from upper bathyal to lower sublittoral condition, which dominated the depositional setting, occurred at 2.70 Ma in the Tainai area, and occurred rapidly during 40,000 years (2.70–2.66 Ma). This shallowing mirrored the shifts induced by global cooling recorded in various evidence such as oxygen isotope data from deep-sea core. Detailed paleodepth fluctuations show four shallowing events that occurred in this area between 2.80 and 2.55 Ma. The third and fourth shallowings at 2.70 and 2.60 Ma were both responses to global climatic cooling corresponding to the oxygen isotope stages G6 and/or G4, and to stage 104, respectively; deduced from the contemporary abundance of cold water species in the study section, observations of shallowing events in the northwestern Pacific Ocean, and the IRD event recorded in high latitude seas.     

Incorporating Restoration in Sustainable Forestry Management: Using Pine-Bark Mulch to Improve Native Species Establishment on Tephra Deposits

Native plant establishment is limited by harsh environmental conditions in areas affected by tephra deposition following volcanic eruptions. Late‐successional species might be lacking even decades after the disturbance. We assessed the effectiveness of pine‐bark mulch, a by‐product of sustainable timber production in the study area, in promoting the establishment and survival of a late‐successional species (Pinus pseudostrobus) and a nitrogen‐fixing legume (Lupinus elegans). We established a factorial experiment in areas covered with tephra during the eruption of the Paricutín volcano in the state of Michoacán, Mexico. After 1 year, P. pseudostrobus survival was significantly higher (p < 0.001) in plots with pine‐bark mulching (46.5%) than in plots without mulching (21.8%). After 2 years, surviving pines with mulching were significantly taller (p= 0.03) than pines without mulching (45.3 ± 3.8 cm and 31.2 ± 3.7 cm, respectively). Lupinus elegans plants survived longer when grown in plots with pine‐bark mulching than without mulching. Mulching reduced tephra temperatures during the dry season (when temperatures can reach up to 58°C 4 cm below the surface of bare tephra). Lupinus elegans plants were affected by herbivory by small rodents, run‐off, and frost at the end of the growing season. Our results suggest that mulching can ameliorate harsh environmental conditions on sites covered with tephra while incorporating a by‐product of sustainable forestry into restoration practice.     

Unique occurrence of pectin-like fibrillar cell wall deposits in xylem fibres of poplar

Using light and electron microscopic techniques, we studied the unique occurrence of fibrillar cell wall deposits in mature xylem fibres from poplar. These cell wall deposits lined the lumen-facing side of the wall, mainly in fibres next to vessel elements. Different lines of evidence point to the pectin-like nature of these fibrillar cell wall deposits. First, specific staining by Alcian Blue 8GX, a dye with high affinity for pectic substances. Second, the strongly reduced staining of the cell wall deposits in microscopic sections treated with pectolytic enzyme. Third, concomitant staining of pits, which are known to consist mainly of pectic substances. Given the pectin-like nature of the fibrillar cell wall deposits as well as their preferred occurrence in fibres neighbouring water-conducting vessel elements, a function for the fibrillar cell wall deposits in lateral water diffusion and stem water storage is hypothesised. The hypothesis is supported by the increased abundance of these cell wall deposits in wood tissue of a drought-sensitive poplar species.     

动脉粥样硬化斑块中脂肪沉积的扫频光热波成像

动脉粥样硬化和易损斑块破裂在全球范围内具有最高的死亡率,超过传染病和癌症导致的死亡率的总和。动脉粥样硬化斑块是由一层很薄的”纤维帽”和导致血栓形成的脂质核心构成。光热波成像是基于对被目标发色团（本文中指脂肪沉积）吸收的光信号强度进行周期调制,从而实现对目标发色团释放的热（红外）信号的调制。这里,我们利用光热波成像来检测来自兔子动脉硬化模型的粥样硬化斑块中脂肪沉积的三维分布。波长为1210纳米的激光被用来靶向检测脂肪。动脉粥样硬化斑块组织在0．1到5赫兹连续扫频的激光的激发下发出光热波,光热波传播到样品表面形成红外辐射温度并被红外相机以25．6帧／秒的速度接收并录制20秒。红外相机上的每一个像素（总共256~256像素）在进行时域傅里叶变换以后得到强度和相位的频域光热波图像。某一特定频率的强度和相位光热波图像对应着脂肪沉积在动脉粥样硬化斑块样品中的横向和纵向分布。对强度和相位光热波图像的分析指出：光热波成像能够用来检测脂肪在动脉粥样硬化斑块中的三维分布,并且脂肪的分布和动脉粥样硬化斑块的形状特征有着紧密联系。     

Effects of Acute Sepsis on Cellular Dynamics and Amyloid Formation in a Mouse Model of Alzheimer’s Disease

Our objective was to investigate how sepsis influences cellular dynamics and amyloid formation before and after plaque formation. As such, APP-mice were subjected to a polymicrobial abdominal infection resulting in sepsis at 2 (EarlySepsis) and 4 (LateSepsis) months of age. Behavior was tested before sepsis and at 5 months of age. We could not detect any short-term memory or exploration behavior alterations in APP-mice that were subjected to Early or LateSepsis. Immunohistochemical analysis revealed a lower area of NeuN⁺ and Iba1⁺ signal in the cortex of Late compared with EarlySepsis animals (p = 0.016 and p = 0.01), with an increased astrogliosis in LateSepsis animals compared with WT-Sepsis (p = 0.0028), EarlySepsis (p = 0.0032) and the APP-Sham animals (p = 0.048). LateSepsis animals had larger areas of amyloid compared with both EarlySepsis (p = 0.0018) and APP-Sham animals (p = 0.0024). Regardless of the analyzed markers, we were not able to detect any cellular difference at the hippocampal level between groups. We were able to detect an increased inflammatory response around hippocampal plaques in LateSepsis compared with APP-Sham animals (p = 0.0003) and a decrease of AQP4 signal far from Sma⁺ vessels. We were able to show experimentally that an acute sepsis event before the onset of plaque formation has a minimal effect; however, it could have a major impact after its onset.     

一平浪盐矿古老岩盐沉积中可培养细菌的系统发育多样性研究

运用纯培养法和基于16S rRNA基因序列的系统发育分析对云南省一平浪盐矿古老岩盐沉积中可培养细菌的多样性进行了研究。用补充0.5~3.5mol/L NaCl的MBA和ISP2琼脂培养基从卤水、岩盐和盐土样品中分离到38株细菌,用细菌通用引物进行16S rRNA基因扩增和序列测定,用相关软件进行序列相似性搜索、比对和系统发育分析。结果表明,38个分离菌株可分为31个物种,属于4个大的系统发育类群(Proteobacteria,Bacteroidetes,Firmicutes,Actinobacteria)、17个科、24个属。多数菌株属于Proteobacteria门(18株,47.3%;Gamma-Proteobacteria,31.5%;Alpha-Proteobacteria,15.8%)和Firmicutes门(13株,34.2%)。这些分离菌株中,至少有3个菌株可能代表3个不同属的3个新物种:Y3、Y15和Y25分别代表Idiomarina属、Salinicoccus属和Saccharospirillum属的新物种;而菌株Y21有可能代表Staphylococcaceae科的一个新属。从以上结果可以看出,一平浪盐矿古老岩盐沉积中存在较为丰富的微生物物种多样性和系统发育多样性,并且潜藏着新的微生物资源。