The transformation of the agricultural population and the urbanisation process in China

"Nine causes for the occurrence of surplus agricultural labour with the modernisation of agriculture have been identified. Several solutions to this problem are presented. Urbanisation of the agricultural population in a way suited to China's characteristics is necessary, important and possible." An example of labor saving through mechanization in Heilongjiang province is presented.

Efficient regeneration of transgenic plants from rice protoplasts and correctly regulated expression of the foreign gene in the plants

Rice is one of the most important crops in the world with 35% of the total population (over two billion people) depending on it as their source of food. It is therefore essential to develop efficient methods for the transformation and regeneration of rice plants in order to delineate the exact regulatory sequences responsible for gene expression and to transfer beneficial genes into this plant. Here, for the first time, we present definitive evidence for the regeneration of a large number of transgenic rice plants after introduction of the bacterial β-glucuronidase gene into rice protoplasts. The presence of integrated copies of this gene was detected in the genome of transgenic plants by DNA hybridization analysis. Furthermore, under the control of regulatory regions from a maize alcohol dehydrogenase sequence, β-glucuronidase gene expression was detected in the roots of transgenic plants. This expression was stimulated up to six fold under anaerobic conditions.

Dexamethasone-dependent inhibition of differentiation of C2 myoblasts bearing steroid-inducible N-ras oncogenes

ras proteins are localized to the plasma membrane where they are postulated to interact with growth factor receptors and other proximal elements in intracellular cascades triggered by growth factors. The molecular events associated with terminal differentiation of certain skeletal myoblasts are inhibited by specific polypeptide growth factors and by constitutive expression of transforming ras oncogenes. To determine whether the inhibitory effects of ras on myogenic differentiation were reversible and to investigate whether muscle-specific genes remained susceptible to ras-dependent repression in terminally differentiated myotubes, the murine myoblast cell line, C2, was transfected with a plasmid containing a mutationally activated human N-ras oncogene under transcriptional control of the steroid-sensitive promoter of the mouse mammary tumor virus long terminal repeat. Addition of dexamethasone to myoblasts bearing steroid-inducible ras oncogenes prevented myotube formation and induction of muscle creatine kinase and acetylcholine receptors. Inhibition of differentiation by dexamethasone occurred in a dose-dependent manner and was a titratable function of ras expression. In the presence of dexamethasone, myoblasts bearing steroid-inducible ras genes retained their dependence on exogenous growth factors to divide and exhibited contact inhibition of growth at confluent densities, indicating that the inhibitory effects of ras on differentiation were independent of cell proliferation. Removal of dexamethasone from N-ras-transfected myoblasts led to fusion and induction of muscle-specific gene products in a manner indistinguishable from control C2 cells. Examination of the effects of culture media conditioned by ras-transfected myoblasts on differentiation of normal C2 cells yielded no evidence for inhibition of differentiation via an autocrine mechanism. In contrast to the ability of N-ras to prevent up-regulation of muscle-specific gene products in myoblasts, induction of N-ras in terminally differentiated myotubes failed to extinguish muscle-specific gene expression. Together, these results suggest that oncogenic ras proteins reversibly activate an intracellular cascade that prevents establishment of the differentiated phenotype. The inability of ras to extinguish muscle-specific gene expression in terminally differentiated myotubes also suggests that ras may interfere with an early step in the pathway of myoblasts toward the differentiated state.

Stimulation of cAMP accumulation and superoxide production in human neutrophils and monocytes

The effect of sodium fluoride (NaF) on superoxide generation and cyclic adenosine monophosphate (cAMP) levels in human neutrophils and monocytes was investigated. NaF (greater than 10 mM) stimulated superoxide (O2-) production in both cell types in a time dependent manner. NaF (0.5 to 20 mM) increased cAMP levels by 1.5- to 3.-fold in both neutrophils and monocytes. Increases in cAMP levels were time-dependent; the maximal level was attained within 5 minutes after the addition of NaF, and cAMP levels remained elevated for up to 10 minutes. Only high concentrations of NaF (10 and 20 mM) increased both cAMP levels and O2- production. Therefore, a direct role of cAMP in O2- generation is not likely. It is speculated that since NaF (greater than 10 mM) can complex with extracellular Ca++, and thus reduce free Ca++ concentration required for O2- generation, a NaF-dependent increase in cAMP may restore cytosolic free Ca++ by mobilizing intracellular stores of Ca++. Further, in view of the proposed involvement of a phosphorylation-dephosphorylation mechanism in the regulation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, we speculate that NaF, by inhibiting phosphoprotein phosphatase activity, may indirectly activate the NADPH oxidase system and thus superoxide generation.

[Preliminary study on the nucleic acid hybridization technic in detecting HSV-2 DNA corresponding sequence of cancer tissues of the uterine cervix]

In this paper, 34 samples, 25 from 18 cervical carcinoma patients and 9 from 8 non-cervical carcinoma patients, were assayed using (alpha-32P) dCTP HSV-2 DNA probe and nucleic acid hybridization technic. It was shown that the positive rates of HSV-2 DNA corresponding sequence were 50% (2/4), 36% (5/14) and 12% (1/8) in the in situ cancer, invasive cancer and non-cervical cancer tissues. No HSV was isolated from 7 cancer specimens which showed a positive reaction by nucleic acid hybridization.

Localized conjunctival amyloidosis associated with extranodal lymphoma

A 62-year-old man was found to have a large asymptomatic amyloid nodule of the conjunctiva. Within the next year, a diffuse mixed small and large cell lymphoma of his scapula developed with amyloid in its stroma. No abnormal serum or urine protein was found. Subsequently, rib and paraspinal masses appeared. After irradiation and chemotherapy, the patient died of bronchopneumonia, 3 years after onset. By immunostaining, the amyloid of both conjunctiva and scapular tumor was of polyclonal immunoglobulin (AL) type, most prominently IgG and lambda chains, with lesser staining for IgA and kappa chains. The tumor cells showed a similar pattern. To our knowledge, this is the first report of systemic lymphoma and localized conjunctival amyloidosis without a serum paraprotein, and the first such association with a lymphoma of this cell type. Immunotyping of conjunctival amyloidosis should be performed to guide the workup for possible systemic disease.

Peanut agglutinin binding as a histochemical tool for diagnosis of eosinophilic granuloma

Histochemical detection of peanut agglutinin binding performed on tissue sections in 11 cases of eosinophilic granuloma of bone revealed simultaneous appearance of the reaction product both at the cell surface and within the cytoplasm (in the Golgi area) of a vast majority of Langerhans' cells. Based on this unique characteristic of Langerhans' cells, peanut agglutinin binding assay may represent a simple and inexpensive tool for morphologic differentiation of eosinophilic granuloma or other types of histiocytosis X from other monocytic and histiocytic lesions in equivocal cases.

The effect of ethanol on the production of lactate, triglycerides, phospholipids, and free fatty acids in the perfused human placenta

Eighteen fresh term placentas from normal deliveries were perfused to determine the biochemical response of the human placenta in the absence and presence of ethanol. The production rates were generally increased by ethanol administration; lactate, 22%; triglycerides, 49%; sphingomyelin, 362%; lecithin, 67%; lipid phosphorus, 780%; free fatty acids, 897%. Only the changes in lipid phosphorus and free fatty acids were significantly different (p less than 0.05). Glucose utilization rates were 600 and 551 mg per hour per placenta for eight control and 10 ethanol runs, respectively. The ethanol utilization rate was 442 mg per hour per placenta. Little difference in ultrastructural appearance between control and ethanol groups was observed at the level of ethanol administered. The general behavior of ethanol metabolism in human placenta seems qualitatively similar to that in the liver.

Effects of mannoprotein mutations on Saccharomyces cerevisiae core oligosaccharide structure

By the combined actions of an endo-alpha-1 leads to 6-mannanase and an endo-beta-N-acetylglucosaminidase, the core oligosaccharides can be released from Saccharomyces cerevisiae X2180 mnn2 mannoproteins. The effects of various mannoprotein mutations were evaluated by structural comparison of these core oligosaccharides with those prepared from double mutant strains with the genotypes mnn1 mnn2, mnn2 mnn3, mnn2 mnn4, and mnn2 mnn5. The results indicate that only the mnn1 lesion has a major effect on the mannoprotein core structure. Whereas the mnn2 mannoprotein yields a core composed of 6 fragments that differ in size from each other by single mannose units, only the two smallest species predominate in the mnn1 mnn2 preparation. This change is correlated with a loss of terminal alpha 1 leads to 3-mannosyl residues, an effect on the mnn1 lesion that is found also in the polysaccharide outer chain and hydroxyamino acid-linked mannooligosaccharides. The mnn3 and mnn5 mutations also had slight effects on the core size, but clear differences in linkage composition were not apparent. The results suggest that core oligosaccharides have an average composition of Man11GlcNAc, whereas Man9GlcNAc is the major oligosaccharide in strains containing the mnn1 defect. These values are 2 to 3 sugars less than those estimated previously (Nakajima, T., and Ballou, C. E. (1975) Biochem. Biophys. Res. Commun. 66, 870-879). Detailed analysis of the major core oligosaccharide from the mnn1 mnn2 mutant revealed that the two mannoses in alpha 1 leads to 3 linkage to the backbone were adjacent to each other and that the oligosacccharide is nearly identical with one isolated from chinese hamster ovary cell membranes (Li, E., and Kornfeld, S. (1979) J. Biol. Chem. 254, 1600-1605). This finding provides strong evidence for the evolutionary conservation of this structural feature of the high mannose core oligosaccharides.