Differences in relative growth rate in 11 grasses correlate with differences in chemical composition as determined by pyrolysis mass spectrometry

Summary Eleven grass species varying in potential relative growth rate (RGR) were investigated for differences in chemical composition by pyrolysis mass spectrometry. The spectral data revealed correlations between RGR and the relative composition of several biopolymers. Species with a low potential RGR contained relatively more cell wall material such as lignin, hemicellulose, cellulose, polysaccharide-bound ferulic acid and hydroxyproline-rich protein, whereas species with a high potential RGR showed relatively more cytoplasmic elements such as protein (other than those incorporated in cell walls) and sterols.     

Growth yields and the efficiency of oxidative phosphorylation of Paracoccus denitrificans during two- (carbon) substrate-limited growth

Paracoccus denitrificans was grown aerobically during two-(carbon)substrate-limitation on mannitol and methanol in chemostat cultures. Theoretical growth parameters were calculated based on the presence of 2 or 3 sites in the electron-transport chain of Paracoccus denitrificans. Experimental growth parameters determined during two-(carbon)substrate growth were conform to the presence of 3 sites of oxidative phosphorylation, while cells grown only on mannitol possessed 2 sites. The maximum growth yield on adenosine triphosphate (ATP), corrected for maintenance requirements, determined in chemostat experiments in which the methanol concentration is less than 2.11 times the mannitol concentration was 8.6 g of biomass. When the methanol concentration was more than 2.11 times the mannitol concentration the maximum growth yield on adenosine triphosphate decreased due to the more energy consuming process of CO₂-assimilation. Cells use methanol only as energy source to increase the amount of mannitol used for assimilation purposes. When the methanol concentration in chemostat experiments was more than 2.11 times the mannitol concentration, all mannitol was used for assimilation and excess energy derived from methanol was used for CO₂-assimilation via the ribulose-bisphosphate cycle. The synthesis of ribulosebisphosphate carboxylase was repressed when the methanol concentration in chemostat experiments was less than 2.11 times the mannitol concentration or when Paracoccus denitrificans was grown in batch culture on both methanol and mannitol. When in chemostat experiments the methanol concentration was more than 2.11 times the mannitol concentration ribulose-bisphosphate carboxylase activity could be demonstrated and CO₂-assimilation will occur. It is proposed that energy produced in excess activates or derepresses the synthesis of the necessary enzymes of the ribulose-bisphosphate cycle in Paracoccus denitrificans. Consequently growth on any substrate will be carbonas well as energy-limited. When methanol is present in the nutrient cells of Paracoccus denitrificans synthesize a CO-binding type of cytochrome c, which is essential for methanol oxidase activity.The reason for the increase in efficiency of oxidative phosphorylation from 2 to 3 sites is most probably the occurrence of this CO-binding type of cytochrome c in which presence electrons preferentially pass through the a-type cytochrome region of the electron-transport chain.Non Standard Abbreviations X prosthetic group of methanol dehydrogenase - q _substrate specific rate of consumption of substrate (mol/g biomass. h.) - Y _substrate, Y _substrate ^MAX are respectively the growth yield and the maximum growth yield corrected for maintenance requirements (g biomass/mol) - m _substrate maintenance requirement (mol substrate/g biomass) - specific growth rate (h^-1) - M [methanol]/[mannitol] ratio in the nutrient - N part of mannitol that is assimilated when M=o - R _m amount of methanol-equivalents that has the same energy content as 1 mannitol-equivalent - P/O _N , P/O _F , P/O _X is the amount of ATP produced during electron-transport of two electrons from respectively NADH+H⁺, FADH₂ and XH₂ to oxygen     

Translocation C:D involving chromosomes 11 and 14

Summary A translocation of material from chromosome 11 to chromosome 14 was identified in a 7-month-old male with microcephaly and developmental delay. The break-points appear to be on the long arm of chromosome 11, close to the centromere, and on the short arm of the 14.     

湖南沅江鼎城段河蚬的性别组成与精子形态特征

本研究以湖南沅江鼎城段河蚬(Corbicula fluminea)为研究对象,在进一步验证该群体性别组成的基础上,分析壳长组成与性别比例之间关系,探讨该群体雄性、雌性和雌雄同体之间关系;同时以单鞭毛精子为参照,分析比较双鞭毛精子的形态特征,以期为我国河蚬的性别发生及生殖适应策略研究提供基础资料。结果显示：沅江鼎城段河蚬(n = 770)雄性、雌性和雌雄同体最小性成熟壳长分别为2.92 mm、5.66 mm和5.30 mm。697只性成熟河蚬中雄性、雌性和雌雄同体的比例近似1︰1︰6。雌雄同体的平均壳长[(22.55 ± 0.33)mm,n = 517]显著大于雄性[(20.44 ± 1.03)mm,n = 95]和雌性[(19.79 ± 0.99)mm,n = 85](P < 0.05),但雄性与雌性的平均壳长之间差异不显著(P > 0.05)。河蚬可以产生单鞭毛和双鞭毛两种类型的精子,单鞭毛精子头长范围4.93 ~ 21.79 μm,平均值(14.27 ± 0.82)μm(n = 30),双鞭毛精子头长范围10.29 ~ 22.04 μm,平均值(15.62 ± 0.62)μm(n = 26)。单、双鞭毛精子头长差异不显著(P > 0.05)。双鞭毛精子(n = 26)长尾的平均长度[(38.07 ± 1.44)μm]显著大于其短尾[(31.08 ± 1.60)μm]和单鞭毛精子(n = 30)尾部长度[(30.15 ± 1.75)μm](P < 0.01),但其短尾与单鞭毛精子的尾部平均长度之间无显著性差异(P > 0.05)。结果表明：湖南沅江鼎城段河蚬为雄性先熟,且可能存在雄性和(或)雌性向雌雄同体转换现象。河蚬具有单鞭毛型和双鞭毛型2种类型的精子,且双鞭毛精子的2个尾部不等长。同域共存河蚬的单鞭毛与双鞭毛精子在运动及受精能力方面的差异值得深入研究。     

Influence of chronic and acute spinal cord injury on skeletal muscle Na+-K+-ATPase and phospholemman expression in humans

Na(+)-K(+)-ATPase is an integral membrane protein crucial for the maintenance of ion homeostasis and skeletal muscle contractibility. Skeletal muscle Na(+)-K(+)-ATPase content displays remarkable plasticity in response to long-term increase in physiological demand, such as exercise training. However, the adaptations in Na(+)-K(+)-ATPase function in response to a suddenly decreased and/or habitually low level of physical activity, especially after a spinal cord injury (SCI), are incompletely known. We tested the hypothesis that skeletal muscle content of Na(+)-K(+)-ATPase and the associated regulatory proteins from the FXYD family is altered in SCI patients in a manner dependent on the severity of the spinal cord lesion and postinjury level of physical activity. Three different groups were studied: 1) six subjects with chronic complete cervical SCI, 2) seven subjects with acute, complete cervical SCI, and 3) six subjects with acute, incomplete cervical SCI. The individuals in groups 2 and 3 were studied at months 1, 3, and 12 postinjury, whereas individuals with chronic SCI were compared with an able-bodied control group. Chronic complete SCI was associated with a marked decrease in [(3)H]ouabain binding site concentration in skeletal muscle as well as reduced protein content of the α(1)-, α(2)-, and β(1)-subunit of the Na(+)-K(+)-ATPase. In line with this finding, expression of the Na(+)-K(+)-ATPase α(1)- and α(2)-subunits progressively decreased during the first year after complete but not after incomplete SCI. The expression of the regulatory protein phospholemman (PLM or FXYD1) was attenuated after complete, but not incomplete, cervical SCI. In contrast, FXYD5 was substantially upregulated in patients with complete SCI. In conclusion, the severity of the spinal cord lesion and the level of postinjury physical activity in patients with SCI are important factors controlling the expression of Na(+)-K(+)-ATPase and its regulatory proteins PLM and FXYD5.     

High Performance Flexible Supercapacitor Electrodes Composed of Ultralarge Graphene Sheets and Vanadium Dioxide

Little is known regarding the effect of the graphene lateral size on the electrochemical performance of hybrid graphene electrode. This work examines the electrochemical performance of a flexible hybrid supercapacitor electrode composed of ultralarge graphene oxide (UGO; mean lateral size of 47 ± 22 μm) and vanadium dioxide (VO₂) nanobelts, referring to a reference electrode composed of small scale graphene oxide (SGO; mean lateral size of 0.8 ± 0.5 μm) and VO₂.Thermal treatment converts UGO/VO₂ and SGO/VO₂ to URGO/VO₂ (denoted VURGO) and SRGO/VO₂ (denoted VSRGO) electrodes, respectively. The sheet resistance of the VURGO film (0.57 ± 0.03 kΩ sq.^–1) was two orders of magnitude lower than that of the VSRGO (55.74 ± 9.35 kΩ sq.^–1). The VURGO hybrid electrode showed a specific capacitance of 769 F g^?1, which was significantly better than the corresponding values for the VSRGO electrode (385 F/g). These results support the notion that the use of ultralarge graphene sheets (≈22 500 μm²) lowers the intersheet resistance due to the presence of fewer intersheet tunneling barriers. This article highlights the potential utility of URGO (as a conductive support) in hybrid electrode containing VO₂ nanobelts for high performance flexible hybrid supercapacitor.     

Lactobacillus plantarum USM8613 Aids in Wound Healing and Suppresses Staphylococcus aureus Infection at Wound Sites

Probiotics and Antimicrobial Proteins - This study aimed to elucidate the targets and mechanisms of anti-staphylococcal effects from bioactive metabolites produced by lactic acid bacteria. We aimed...