Organogenesis in callus derived from stem and leaf tissues of apple and cherry rootstocks

Callus formation from stem internodes of the apple rootstocks M.9, M.25, M.26, M.27 and the cherry rootstock Colt, and from pith of Nicotiana tabacum cv. Wisconsin 38 was initiated on 4 -naphthaleneacetic acid (NAA)-based media (2.0–10.0 mg1^-1). Transfer of callus to corresponding media lacking NAA allowed regeneration of shoots from callus of M.25, M.27, Colt and tobacco but not of M.9 and M.26. With M.25 phloroglucinol (PG) depressed regeneration from 30 to 10% and no regeneration was observed in cultures grown in the presence of casein hydrolysate (CH) and glutathione (GSH).Organogenesis was also obtained from leaf discs of M.27 employing 6-benzyl-aminopurine (BAP) at 5.0mg 1^-1 and 2,4-dichlorophenoxy acetic acid (2,4-D) at 0.1 mg1^-1. The regenerated shoots have been multiplied and rooted.Organogenesis also occurred in M.26 from small (1–2mm), green, compact embryoid-like structures derived from stem and leaf surfaces of excised axillary shoots. These structures differentiated into shoots at a low frequency (< 1%) on media containing BAP (1.0mg1^-1) and indole-3-butyric acid (IBA) (0.1 mg1^-1) and could also be micropropagated by subsequent axillary shoot proliferation.     

Effect of temperature on the stability and activity of crystalline ox liver nuclear and mitochondrial glutamate dehydrogenases

A study on the response of the stability and activity of crystalline ox liver nuclear and mitochondrial glutamate dehydrogenases to temperature variations has been carried out. The thermodynamic properties of the heat inactivation process and of the reaction with the substrates glutamate and α-ketoglutarate have been investigated. The heat inactivation of nuclear glutamate dehydrogenase proceeds at a faster rate than that of the mitochondrial enzyme in the temperature range 40–51 °C; the enthalpy of activation of the inactivation process is higher and the entropy is almost double, compared to the values of mitochondrial glutamate dehydrogenase. The effect of temperature on the maximal velocity shows that, with both glutamate and α-ketoglutarate, the enthalpy of activation with nuclear glutamate dehydrogenase is double and the decrease in entropy almost half of the values of the mitochondrial enzyme. The variation of the apparent K_m with temperature shows a decrease of the affinity of both enzymes for glutamate, with no major difference in the thermodynamic properties of the reaction. With α-ketoglutarate, on the other hand, the affinity of nuclear glutamate dehydrogenase decreased, whereas that of the mitochondrial enzyme increased with temperature. The process is therefore exothermic with the former enzyme, endothermic with the latter; furthermore, it occurs with a decrease in enthropy with nuclear glutamate dehydrogenase, but with a large increase with the mitochondrial enzyme. The studies on the effect of temperature on the activity were carried out in the range 20–44 °C.     

Linkage relationships between regulatory and structural gene loci involved in zein synthesis in maize

Summary The synthesis of at least 15 zein polypeptides is under the control of regulatory gene loci. One of these, Opaque-2 (chromosome 7, position 16) strongly reduces the zein accumulation without modifying the zein molecular components. The linkage relationship between the regulatory gene 02 and the 5 structural loci (Zp1, Zp2, Zp3, Zp6, Zp12) segregating with sample Mendelian ratios have been studied. Zp1, Zp2, Zp3 are closely linked to each other; moreover this gene cluster is located on chromosome 7 at 5.5 cM from the Opaque-2 locus. The structural loci Zp6 and Zp12 are not linked with each other, with the 02 locus or with Zp1, Zp2, Zp3. From our data it follows that the zein structural genes are located in at least three positions on the maize genome. The scattering in the genome of the genes controlled by the Opaque-2 locus suggests a transacting role for this regulatory element.     

Changes in carbohydrates and lipids during embryonic development ofAntheraea mylitta (Lepidoptera)

Changes in carbohydrate and lipid metabolism during embryonic development inAntheraea mylitta were studied. While carbohydrates were metabolized during early embryogenesis, lipids were catabolised at the later stages. A significant increase in both total carbohydrates and glycogen on days 5 and 6 suggested the concurrent occurrence of both gluconeogenesis and glycogenesis. As the development of the embryo proceeds, both lipids and carbohydrates were utilised, resulting in the increase in the concentration of citrate, pyruvate and lactate.     

Hepatocyte population dynamics during hydrocortisone and thioacetamide treatment

Summary The orderly organization in a number of discrete classes of weight persists in the hepatocytes during acute and chronic poisoning with thioacetamide and during a prolonged treatment with hydrocortisone, though many striking cytological and structural changes occur in the liver.The number of hepatocyte classes decreases under hydrocortisone treatment and during acute and chronic thioacetamide poisoning, and increases during recovery after acute thioacetamide poisoning and during the late phases of chronic thioacetamide poisoning. This is due to decrements and increments in dry mass of the hepatocytes, which occur by steps, through repeated losses and additions of a constant amount of solids substantially corresponding to the class period.Such a mechanism is similar to that acting in the hepatocyte atrophy due to starvation and in the hepatocyte enlargement occurring during postnatal development. Therefore, the increment and the decrement in dry mass by defined steps takes place in the hepatocytes in both physiological and pathological conditions.This work was supported by a grant of the Consiglio Nazionale delle Ricerche, Rome, Italy.     

Production of gramicidin S synthetases by Bacillus brevis in continuous culture.

The effects of different nutrient limitations on the production of the two enzymes of gramicidin S biosynthesis were studied during continuous culture of Bacillus brevis. Gramicidin S synthetases I and II were produced in the chemostat under carbon, nitrogen, phosphorus or sulphur limitation. The growth rate, rather than the nature of the limitation, was the major controlling factor in regulating the level of the gramicidin S synthetases. Synthetase production was low at high dilution rates (0.45 to 0.50 h-1) but increased as the dilution rate was lowered. The highest specific activities occurred at dilution rates that were different for each type of limitation: 0.40 h-1 for nitrogen, 0.32 h-1 for carbon, 0.24 h-1 for sulphur and 0.20 h-1 for phosphorus. Phosphorus limitation gave the highest specific activities. At low dilution rates (0.10 to 0.15 h-1), enzyme activities were again low. Sporulation occurred under carbon limitation, but at a lower dilution rate than that which supported optimal gramicidin S synthetase formation. The specific productivity of the synthetases in the chemostat was higher than the highest productivity obtained in batch growth.     

The helical content of the YscP molecular ruler determines the length of the Yersinia injectisome

The length of the Yersinia injectisome needle is determined by the protein YscP, which could act as a molecular ruler. The analysis of the correlation between the size of YscP and the needle length in seven wild-type strains of Yersinia enterocolitica reinforced this hypothesis but hinted that the secondary structure of YscP might influence needle length. Hence, 11 variants of YscP₅₁₅ were generated by multiple Pro or Gly substitutions. The needle length changed in inverse function of the helical content, indicating that not only the number of residues but also their structure controls length. Taking the secondary motifs into account, Pro/Gly-variants were subjected to in silico modelling to simulate the extension of YscP upon needle growth. The calculated lengths when the helical content is preserved correlated strikingly with the measured needle length, with a constant difference of ∼29 nm, which corresponds approximately to the size of the basal body. These data support the ruler model and show that the functional ruler has a helical structure.     

Using LiDAR Data to Measure the 3D Green Biomass of Beijing Urban Forest in China

The purpose of the paper is to find a new approach to measure 3D green biomass of urban forest and to testify its precision. In this study, the 3D green biomass could be acquired on basis of a remote sensing inversion model in which each standing wood was first scanned by Terrestrial Laser Scanner to catch its point cloud data, then the point cloud picture was opened in a digital mapping data acquisition system to get the elevation in an independent coordinate, and at last the individual volume captured was associated with the remote sensing image in SPOT5(System Probatoired''Observation dela Tarre)by means of such tools as SPSS (Statistical Product and Service Solutions), GIS (Geographic Information System), RS (Remote Sensing) and spatial analysis software (FARO SCENE and Geomagic studio11). The results showed that the 3D green biomass of Beijing urban forest was 399.1295 million m³, of which coniferous was 28.7871 million m³ and broad-leaf was 370.3424 million m³. The accuracy of 3D green biomass was over 85%, comparison with the values from 235 field sample data in a typical sampling way. This suggested that the precision done by the 3D forest green biomass based on the image in SPOT5 could meet requirements. This represents an improvement over the conventional method because it not only provides a basis to evalue indices of Beijing urban greenings, but also introduces a new technique to assess 3D green biomass in other cities.     

Sequential Application of Ligand and Structure Based Modeling Approaches to Index Chemicals for Their hH4R Antagonism

The human histamine H₄ receptor (hH₄R), a member of the G-protein coupled receptors (GPCR) family, is an increasingly attractive drug target. It plays a key role in many cell pathways and many hH₄R ligands are studied for the treatment of several inflammatory, allergic and autoimmune disorders, as well as for analgesic activity. Due to the challenging difficulties in the experimental elucidation of hH₄R structure, virtual screening campaigns are normally run on homology based models. However, a wealth of information about the chemical properties of GPCR ligands has also accumulated over the last few years and an appropriate combination of these ligand-based knowledge with structure-based molecular modeling studies emerges as a promising strategy for computer-assisted drug design. Here, two chemoinformatics techniques, the Intelligent Learning Engine (ILE) and Iterative Stochastic Elimination (ISE) approach, were used to index chemicals for their hH₄R bioactivity. An application of the prediction model on external test set composed of more than 160 hH₄R antagonists picked from the chEMBL database gave enrichment factor of 16.4. A virtual high throughput screening on ZINC database was carried out, picking ∼4000 chemicals highly indexed as H₄R antagonists'' candidates. Next, a series of 3D models of hH₄R were generated by molecular modeling and molecular dynamics simulations performed in fully atomistic lipid membranes. The efficacy of the hH₄R 3D models in discrimination between actives and non-actives were checked and the 3D model with the best performance was chosen for further docking studies performed on the focused library. The output of these docking studies was a consensus library of 11 highly active scored drug candidates. Our findings suggest that a sequential combination of ligand-based chemoinformatics approaches with structure-based ones has the potential to improve the success rate in discovering new biologically active GPCR drugs and increase the enrichment factors in a synergistic manner.