First record of the grape leafhopper Erythroneura vulnerata Fitch (Hom., Cicadellidae) in Europe

Abstract:  The leafhopper Erythroneura vulnerata Fitch is native to North America, where it infests wild and cultivated grapes. In July 2004, E. vulnerata was recorded for the first time on Vitis vinifera L. (cv. Cabernet Sauvignon) in north-eastern Italy (Veneto region). This record is assumed to be the first in Europe. Preliminary observations on the pest distribution, seasonal abundance and the extent of symptoms in north-eastern Italy are reported.     

Hepatic myelolipoma in two Goeldi's monkeys from South America held captive

Two cases of hepatic myelolipoma in Goeldi's monkeys from South America are described. One was a female evaluated due progressive abdominal distension. Ultrasound and computed tomography detected hepatic mass. Partial hepatectomy was performed, but the monkey died after surgery. Case 2 was a male that died suddenly, showing non‐specific clinical signs.     

Alteration of the physical and chemical structure of the primary cell wall of growth-limited plant cells adapted to osmotic stress

Cells of tobacco (Nicotiana tabacum L.) adapted to grow in severe osmotic stress of 428 millimolar NaCl (−23 bar) or 30% polyethylene glycol 8000 (−28 bar) exhibit a drastically altered growth physiology that results in slower cell expansion and fully expanded cells with volumes only one-fifth to one-eighth those of unadapted cells. This reduced cell volume occurs despite maintenance of turgor pressures sometimes severalfold higher than those of unadapted cells. This report and others (NM Iraki et al [1989] Plant Physiol 90: 000-000 and 000-000) document physical and biochemical alterations of the cell walls which might explain how adapted cells decrease the ability of the wall to expand despite diversion of carbon used for osmotic adjustment away from synthesis of cell wall polysaccharides. Tensile strength measured by a gas decompression technique showed empirically that walls of NaCl-adapted cells are much weaker than those of unadapted cells. Correlated with this weakening was a substantial decrease in the proportion of crystalline cellulose in the primary cell wall. Even though the amount of insoluble protein associated with the wall was increased relative to other wall components, the amount of hydroxyproline in the insoluble protein of the wall was only about 10% that of unadapted cells. These results indicate that a cellulosic-extensin framework is a primary determinant of absolute wall tensile strength, but complete formation of this framework apparently is sacrificed to divert carbon to substances needed for osmotic adjustment. We propose that the absolute mass of this framework is not a principal determinant of the ability of the cell wall to extend.     

Solute Accumulation in Tobacco Cells Adapted to NaCl

Cells of Nicotiana tabacum L. var Wisconsin 38 adapted to NaCl (up to 428 millimolar) which have undergone extensive osmotic adjustment accumulated Na⁺ and Cl⁻ as principal solutes for this adjustment. Although the intracellular concentrations of Na⁺ and Cl⁻ correlated well with the level of adaptation, these ions apparently did not contribute to the osmotic adjustment which occurred during a culture growth cycle, because the concentrations of Na⁺ and Cl⁻ did not increase during the period of most active osmotic adjustment. The average intracellular concentrations of soluble sugars and total free amino acids increased as a function of the level of adaptation; however, the levels of these solutes did not approach those observed for Na⁺ and Cl⁻. The concentration of proline was positively correlated with cell osmotic potential, accumulating to an average concentration of 129 millimolar in cells adapted to 428 millimolar NaCl and representing about 80% of the total free amino acid pool as compared to an average of 0.29 millimolar and about 4% of the pool in unadapted cells. These results indicate that although Na⁺ and Cl⁻ are principal components of osmotic adjustment, organic solutes also may make significant contributions.     

Metabolic changes associated with adaptation of plant cells to water stress

Suspension cultured cells of tomato (Lycopersicon esculentum Mill. cv VFNT Cherry) adapted to water stress induced with polyethylene glycol 6000 (PEG), exhibit marked alterations in free amino acid pools (Handa et al. 1983 Plant Physiol 73: 834-843). Using computer simulation models the in vivo rates of synthesis and utilization and compartmentation of free amino acid pools were determined from ¹⁵N labeling kinetics after substituting [¹⁵N]ammonium and [¹⁵N]nitrate for the ¹⁴N salts in the culture medium of cell lines adapted to 0% and 25% PEG. The 300-fold elevated proline pool in 25% PEG adapted cells is primarily the consequence of a 10-fold elevated rate of proline synthesis via the glutamate pathway. Ornithine was insufficiently labeled to serve as a major precursor for proline. Our calculations suggest that the rate of proline synthesis only slightly exceeds the rate required to sustain both protein synthesis and proline pool maintenance with growth. Mechanisms must operate to restrict proline oxidation in adapted cells. The kinetics of labeling of proline in 25% PEG adapted cells are consistent with a single, greatly enlarged metabolic pool of proline. The depletion of glutamine in adapted cells appears to be a consequence of a selective depletion of a large, metabolically inactive storage pool present in unadapted cultures. The labeling kinetics of the amino nitrogen groups of glutamine and glutamate are consistent with the operation of the glutamine synthetase-glutamate synthase cycle in both cell lines. However, we could not conclusively discriminate between the exclusive operation of the glutamine synthetase-glutamate synthase cycle and a 10 to 20% contribution of the glutamate dehydrogenase pathway of ammonia assimilation. Adaptation to water stress leads to increased nitrogen flux from glutamate into alanine and γ-aminobutyrate, suggesting increased pyruvate availability and increased rates of glutamate decarboxylation. Both alanine and γ-aminobutyrate are synthesized at rates greatly in excess of those simply required to maintain the free pools with growth, indicating that these amino acids are rapidly turned over. Thus, both synthesis and utilization rates for alanine and γ-aminobutyrate are increased in adapted cells. Adaptation to stress leads to increased rates of synthesis of valine and leucine apparently at the expense of isoleucine. Remarkably low ¹⁵N flux via the aspartate family amino acids was observed in these experiments. The rate of synthesis of threonine appeared too low to account for threonine utilization in protein synthesis, pool maintenance, and isoleucine biosynthesis. It is possible that isoleucine may be deriving carbon skeletons from sources other than threonine. Tentative models of the nitrogen flux of these two contrasting cell lines are discussed in relation to carbon metabolism, osmoregulation, and nitrogenous solute compartmentation.     

Somaclonal variation in tuber disc-derived populations of potato

Summary Approximately 1,600 potato (Solanum tuberosum L.) plants of the cultivar Superior were regeneratedin vitro from meristems adventitiously initiated on tuber disc expiants. Direct regeneration from tuber disc cells, by passing a callus intermediary, is efficient and results in low frequencies of plants with gross phenotypic aberrations. The somaclonal plant population was statistically characterized in field plots over five asexual generations and in three diverse locations. When compared in advanced generations to a large population of control plants propagated from stem cuttings, the means of the somaclonal population were significantly different, often shifted in the desirable direction, for 16 of 22 horticulturally important traits. Somaclonal population variances statistically exceeded those of the controls for 13 of the 22 traits. Regressions between consecutive tuber generations and between locations or replications (blocks) within a generation were significant in the somaclonal population for all traits analyzed. In a few instances, significant control population regressions occurred that are interpreted to be the result of non-random, non-genetic factors primarily affecting control plants of low vigor. Selected somaclones exhibiting desirable alterations for yield, tuber number and shape, and vigor were stable over more than two consecutive asexual generations.Research supported by a grant from NPI, 417 Wakara Way, Salt Lake City, UT 84108     

Prevalence of hepatitis C Virus infection among hemophiliacs in Central Brazil

In order to investigate the hepatitis C virus (HCV) infection prevalence and risk factors in hemophiliacs in Central Brazil, 90 patients were interviewed and serum samples tested for HCV RNA and anti-HCV antibodies. An overall prevalence of 63.3% (CI 95%: 53.0-72.7) was found. Multivariate analysis of risk factors showed that number of blood transfusions was significantly associated with this infection. Most hemophiliacs received locally produced cryoprecipitate. All infected patients were transfused before the screening of blood units for anti-HCV. However, hemophiliacs who received exclusively screened cryoprecipitate were HCV negative. It confirms the expected decline in transfusion-acquired hepatitis C.     

Notochord-derived BMP antagonists inhibit endothelial cell generation and network formation

Embryonic blood vessel formation is initially mediated through the sequential differentiation, migration, and assembly of endothelial cells (ECs). While many molecular signals that promote vascular development have been identified, little is known about suppressors of this process. In higher vertebrates, including birds and mammals, the vascular network forms throughout the embryonic disk with the exception of a region along the midline. We have previously shown that the notochord is responsible for the generation and maintenance of the avascular midline and that BMP antagonists expressed by this embryonic tissue, including Noggin and Chordin, can mimic this inhibitory role. Here we report that the notochord suppresses the generation of ECs from the mesoderm both in vivo and in vitro. We also report that the notochord diminishes the ability of mature ECs to organize into a primitive plexus. Furthermore, Noggin mimics notochord-based inhibition by preventing mesodermal EC generation and mature EC network formation. These findings suggest that the mesoderm surrounding the midline is competent to give rise to ECs and to form blood vessels, but that notochord derived-BMP antagonists suppress EC differentiation and maturation processes leading to inhibition of midline vessel formation.     

Antiviral activity of medicinal plant-derived products against SARS-CoV-2

This review presents information from several studies that have demonstrated the antiviral activity of extracts (Andrographis paniculata, Artemisia annua, Artemisia afra, Cannabis sativa, Curcuma longa, Echinacea purpurea, Olea europaea, Piper nigrum, and Punica granatum) and phytocompounds derived from medicinal plants (artemisinins, glycyrrhizin, and phenolic compounds) against SARS-CoV-2. A brief background of the plant products studied, the methodology used to evaluate the antiviral activity, the main findings from the research, and the possible mechanisms of action are presented. These plant products have been shown to impede the adsorption of SARS-CoV-2 to the host cell, and prevent multiplication of the virus post its entry into the host cell. In addition to antiviral activity, the plant products have also been demonstrated to exert an immunomodulatory effect by controlling the excessive release of cytokines, which is commonly associated with SARS-CoV-2 infections.