Annual weed distributions can be mapped with kriging

The authenticity of weed distribution maps prepared by the geostatistical estimation method, kriging, was investigated. We concentrated on the total number of weed plants and the dominant weed genus Veronica spp. in a 2.1-ha field of winter wheat. Different sampling distances were evaluated. Our analyses showed that kriging weed densities based on seedling counts collected in, 0.25.m² circles in a sampling grid of approximately 10 m × 10 m gave good agreement with actual observations. Reducing the sampling grid to 20 m × 30 m gave poor agreement. New sampling methods combined with positioning devices and injection sprayers are discussed with reference to site-specific weed management.     

紫外分光光度法测定氟苯尼考及其注射液的含量

采用紫外分光光度法测定氟苯尼考原料药及其注射液的含量。实验结果表明,在0.05~0.5 mg/mL浓度范围内,氟苯尼考的吸光度与浓度呈现良好的线性关系(r=0.9997,n=6);与法定的高效液相色谱法检测结果无差异。     

Protein requirements of preschool children consuming rice-milk,rice-toasted mung bean,and rice diets

Rice-milk and rice-toasted mung bean diets, and a high-protein rice (IR58 milled rice) were evaluated as part of a study on the protein requirements of toddlers consuming rice-based diets following the multilevel N balance method. Milk or mung bean contributed 1/3 of dietary N. At a daily energy intake of 418 kJ/kg body weight, weight losses were observed for all diets. The safe level of protein intakes obtained allowing 10 mg N/kg body weight/day for miscellaneous integumental losses and 15 mg N/kg body weight/day for growth was 1.11 g/kg body weight/day for the rice-milk diet and 1.34 g for the rice-mung bean diet. Preliminary data on four children indicate a safe level of protein intake of 1.44 g/kg/day for the IR58 milled rice. The protein quality of the high-protein rice as determined by the very short term N balance index on three children was 79–80% relative to milk.     

Distribution and properties of lactate dehydrogenase isoenzymes in red and white muscle of freshwater fish

The distribution and kinetics of LDH isoenzymes in red and white muscles of 5 species of salmonids, 4 species of cyprinids and one coregonid species were studied. In all species the white muscles are characterized by the occurrence of only the most cathodic isoenzymes, or groups of isoenzymes. The red muscles contained either the full set of isoenzymes (cyprinids) or a selection in which the anodic forms dominated (salmonids, coregonid). The most striking difference between the two types of muscle was met inCoregonus sp. The temperature profiles of pyruvate affinity are similar in all species of fish studied. On the other hand, K_m(pyr) values and degree of pyruvate inhibition are closely related and vary greatly with temperature, with the taxonomic position (and thus biology) of the species, and with electrophoresic mobility of the isoenzyme. Highest affinity and strongest inhibition occurred in the anodic (H₄) isoenzymes of cyprinids at low temperature; lowest affinity and zero inhibition in the cathodic isoenzymes (M₄ M₄) of salmonids and coregonids at high temperature. In salmonids the more recently duplicated loci of the M-group of isoenzymes possess identical K_m values at all temperatures, whereas the two older M and H loci differ greatly in this respect. Thus the more recent duplication of LDH loci in salmonids and coregonids may be seen as a mechanism by which the tetramers required for LDH activity can be constructed from more closely related subunits than are provided by the older M and H loci.Some problems in connection with the determination of the kinetic constants of the lactate oxidase reaction are discussed and it is suggested that an alkaline, pyruvate trapping system provides conditions which are more realistic than those of other assay systems. The K_m(lactate) values found are in the biological range and, at 20°C, provide further circumstantial evidence that the red muscles of fish should be capable of oxidizing the lactate produced by the white muscles during strenuous exercise. At 4°C the K_m(lactate) values are abnormally high in all muscle preparations and thus are not correlated with the K_m(pyruvate) values which are lowest at this temperature.     

Combined use of platelet rich plasma and vitamin C positively affects differentiation in vitro to mesodermal lineage of adult adipose equine mesenchymal stem cells

Repair of injured soft and hard tissues in horses can benefit greatly from the use of regenerative therapies with mesenchymal stem cells (MSC). Vitamin-C and platelet-rich-plasma had been used for in vitro differentiation of MSC. This study was aimed to evaluate the effect of vitamin-C, platelet-rich-plasma and their combination on the in vitro differentiation of adipose horse MSC. We isolated MSC from horse fat and differentiated them in vitro into osteogenic and chondrogenic lineages, as demonstrated by specific staining and RT-qPCR of selected genes. Combining vitamin-C and plasma-rich-platelet positively affected the ability of MSC to differentiate in vitro into mesodermal lineages during 14 days of culture; this effect was not as marked when differentiation was attempted for 21 days. This provides valuable information on the effect of combined use of these molecules in regenerative therapies and their potential application along stem cells for lesions of musculoskeletal tissue in sport horses.     

ER tubules mark sites of mitochondrial division

Mitochondrial structure and distribution are regulated by division and fusion events. Mitochondrial division is regulated by Dnm1/Drp1, a dynamin-related protein that forms helices around mitochondria to mediate fission. Little is known about what determines sites of mitochondrial fission within the mitochondrial network. The endoplasmic reticulum (ER) and mitochondria exhibit tightly coupled dynamics and have extensive contacts. We tested whether ER plays a role in mitochondrial division. We found that mitochondrial division occurred at positions where ER tubules contacted mitochondria and mediated constriction before Drp1 recruitment. Thus, ER tubules may play an active role in defining the position of mitochondrial division sites.