生态系统性状对宏生态研究的启示与挑战

功能性状在器官-物种-种群-群落-生态系统水平都具有其特定的适应或功能优化的意义,但目前对功能性状的测定和研究大都局限于器官或物种水平。然而,当前高速发展的宏生态新研究技术和方法(如遥感观测、通量观测、模型模拟)的研究对象都是在生态系统或区域尺度上,如何将传统功能性状与其相连结并服务于生态环境问题和全球变化问题是科学界的一大难题。为了解决传统性状与宏生态研究"尺度不统一"和"量纲不统一"的难题,研究人员最新发展了"生态系统性状(Ecosystem traits, ESTs)"概念体系,并从"理念-数据源-推导方法-应用"等多角度为后续研究提供了可借鉴案例。生态系统性状将传统性状研究从器官水平拓展到了群落和生态系统水平,以单位土地面积为基础构建了传统性状与宏生态研究(或地学研究)的桥梁,开启了性状研究从"器官到群落"、从"经典理论验证到宏观应用"的美好愿景,为多学科交叉提供了新思路。然而,它在方法学和数据源等方面还存在诸多问题与挑战;在此,我们呼吁相关专家从研究方法、概念体系和应用实践上赋予"生态系统性状"更强大的生命力,尤其从动物群落性状和微生物群落性状等角度。本文在深入解读先前生态性状概念体系、理论意义和潜在挑战的基础上,结合最新进展进行了补充,希望通过广泛讨论,完善生态系统性状概念体系,逐步形成"以性状为基础的生态系统生态学"新研究框架,切实推动宏生态研究和区域生态环境问题的解决。     

Properties of gallic acid-induced extracellular laccase of Botrytis cinerea

The properties of the extracellular laccase produced by Botrytis cinerea induced by garlic acid are compared with the laccase produced by Botrytis in the presence of grape juice. The extra- and intracellular laccases are compared and found to be very similar.     

Ultrastructural and carbohydrate histochemical study of the Vater-Pacini corpuscles in the digital pads of the North American raccoon (<Emphasis Type="Italic">Procyon lotor</Emphasis>), with special regard to basic function

Numerous and very large Vater-Pacini corpuscles were observed in the forefoot digital pads of the North American raccoon (Procyon lotor). In addition to ultrastructure, the distribution and selectivity of complex glycoconjugates in this sensory corpuscle type were examined by carbohydrate histochemical techniques, in particular lectin histochemistry. The Vater-Pacini corpuscles present showed the typical lamellar structure known for mammals and contained high amounts of neutral and acidic glycoconjugates with various saccharide residues (α-l-fucose, β-d-galactose, sialic acid) in a specific intracorpuscular distribution pattern, including variations between the outer lamellae and the inner core. The results obtained are discussed with regard to possible functions of the Vater-Pacini corpuscles found in the raccoon forefoot pads. The corpuscular glycoconjugate components may furnish a high and differentiated viscoelasticity for rapid pressure transmission within the large Vater-Pacini corpuscles. Thus, the digital pads of the forepaws can be considered as part of a specific mechanoreceptor system related to excellent object manipulation properties in this mammalian species.     

Macroscopic anisotropic bone material properties in children with severe osteogenesis imperfecta

Children with severe osteogenesis imperfecta (OI) typically experience numerous fractures and progressive skeletal deformities over their lifetime. Recent studies proposed finite element models to assess fracture risk and guide clinicians in determining appropriate intervention in children with OI, but lack of appropriate material property inputs remains a challenge. This study aimed to characterize macroscopic anisotropic cortical bone material properties and investigate relationships with bone density measures in children with severe OI. Specimens were obtained from tibial or femoral shafts of nine children with severe OI and five controls. The specimens were cut into beams, characterized in bending, and imaged by synchrotron radiation X-ray micro-computed tomography. Longitudinal modulus of elasticity, yield strength, and bending strength were 32–65% lower in the OI group (p < 0.001). Yield strain did not differ between groups (p ≥ 0.197). In both groups, modulus and strength were lower in the transverse direction (p ≤ 0.009), but anisotropy was less pronounced in the OI group. Intracortical vascular porosity was almost six times higher in the OI group (p < 0.001), but no differences were observed in osteocyte lacunar porosity between the groups (p = 0.086). Volumetric bone mineral density was lower in the OI group (p < 0.001), but volumetric tissue mineral density was not (p = 0.770). Longitudinal OI bone modulus and strength were correlated with volumetric bone mineral density (p ≤ 0.024) but not volumetric tissue mineral density (p ≥ 0.099). Results indicate that cortical bone in children with severe OI yields at the same strain as normal bone, and that their decreased bone material strength is associated with reduced volumetric bone mineral density. These results will enable the advancement of fracture risk assessment capability in children with severe OI.     

Biomechanical and morphological properties of the multiparous ovine vagina and effect of subsequent pregnancy

Pelvic floor soft tissues undergo changes during the pregnancy. However, the degree and nature of this process is not completely characterized. This study investigates the effect of subsequent pregnancy on biomechanical and structural properties of ovine vagina. Vaginal wall from virgin, pregnant (in their third pregnancy) and parous (one year after third vaginal delivery) Swifter sheep (n = 5 each) was harvested. Samples for biomechanics and histology, were cut in longitudinal axis (proximal and distal regions). Outcome measurements describing Young’s modulus, ultimate stress and elongation were obtained from stress-strain curves. For histology samples were stained with Miller's Elastica staining. Collagen, elastin and muscle cells and myofibroblasts contents were estimated, using image processing techniques. Statistical analyses were performed in order to determine significant differences among experimental groups. Significant regional differences were identified. The proximal vagina was stiffer than distal, irrespective the reproductive status. During the pregnancy proximal vagina become more compliant than in parous (+47.45%) or virgin sheep (+64.35%). This coincided with lower collagen (−15 to −21%), higher elastin (+30 to +60%), and more smooth muscle cells (+17 to +37%). Vaginal tissue from parous ewes was weaker than of virgins, coinciding with lower collagen (−10%), higher elastin (+50%), more smooth muscle cells (+20%). It could be proposed that after pregnancy biomechanical properties of vagina do not recover to those of virgins. Since elastin has a significant influence on the compliance of soft tissues and collagen is the main “actor” regarding strength, histological analysis performed in this study justifies the mechanical behavior observed.     

Structural comparison and enhanced enzymatic hydrolysis of eucalyptus cellulose via pretreatment with different ionic liquids and catalysts

Eucalyptus was fractionated with mild alkaline process, and the obtained cellulose fraction was pretreated with various ionic liquids (ILs) to enhance the enzymatic saccharification. The results showed that the ILs used was efficient for the hydrolysis of cellulose, with the maximum total reducing sugars (TRS) yield over 80% at 50 °C. The regenerated cellulose substrate exhibited a significant improvement about 4.4–6.4 folds enhancement on saccharification rate during the first 4 h reaction. The crystallinity index (CrI) of cellulose via 1-ally-3-methylimidazolium ([AMIM]Cl) pretreatment was significantly decreased from 70.2% to 31.2%, resulting in structural change from cellulose I to cellulose II, which enabled the cellulase enzymes easier access to hydrolyze cellulose. However, 1-butyl-3methylimidazolium acesulfamate ([BMIM]Ace) pretreatment had no large effect on the CrI although a high conversion yield in glucose was obtained. The surface morphologies of the regenerated substrate which was pretreated via 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) and 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac) showed more porous and incompact network of cellulose when compared with the untreated substrate. This result indicated a better accessibility by cellulases to the cellulose surface. Besides, a certain amount of catalysts such as MgCl₂ and H₂SO₄ could improve the rate of enzymatic saccharification.     

Age-related changes in tactile spatial resolution from 6 to 16 years old

The aim of this study was to determine age-related changes in tactile spatial resolution from 6 to 16 years old. Two hundred and twenty-two healthy children (105 boys and 117 girls) were assessed. The tactile spatial resolution threshold was determined using a classic set of JVP domes with a procedure adapted for children. Preadolescence appears to be an important step in tactile spatial resolution since children aged between 6 and 9 years old had a worse tactile spatial resolution than older children. Both peripheral and central explanations for this improvement of tactile spatial resolution with age are considered. The authors suggest that cortical maturational processes are likely to explain the better results of older children.     

Biocatalytic Production of Acyclic Bis[bibenzyls] from Dihydroresveratrol by Crude Momordica charantia Peroxidase

Biotransformation of dihydroresveratrol by crude Momordica charantia peroxidase provided six new acyclic bis[bibenzyls] 1 – 6 . Their structures were established on the basis of NMR and MS analyses as C? C, C? O? C, and C? CH₂? C dimers of dihydroresveratrol. Compounds 1 – 6 were tested for antiproliferative activity against human prostate cancer PC3 cell line in vitro, and 2 and 6 were found to be more potent than the parent compound.