Drought tolerance in faster- and slower-growing black spruce (Picea mariana) progenies: II. Osmotic adjustment and changes of soluble carbohydrates and amino acids under osmotic stress

The possibility was considered that osmotic adjustment, the ability to accumulate solutes in response to water stress, may contribute to growth rate differences among closely-related genotypes of trees. Progeny variation in osmotic adjustment and turgor regulation was investigated by comparing changes in osmotic and pressure potentials, soluble carbohydrates, and amino acids in osmotically stressed seedlings in 4 full-sib progenies of black spruce [ Picea mariana (Mill.) B. S. P.] that differed in growth rate under drought. Osmotic stress was induced by a stepwise increase in the concentration of polyethylene glycol (PEG)-3350 from 10 (w/v) to 18 and 25%, which provided osmotic potentials in solution culture of -0.4, -1.0 and -2.0 MPa each for 3 days. All 4 progenies maintained a positive cell turgor even at 25% PEG, due to a significant decline in osmotic potential. Although total amino acids, principally proline, increased, ca 60% of the decrease in osmotic potential was attributable to soluble carbohydrates and glucose was the major osmoregulating solute. There was little progeny variation in any of measured parameters in unstressed seedlings. Compared to two slower-growing progenies, the two progenies capable of more vigorous growth under drought in the field accumulated more soluble carbohydrates (mainly glucose and fructose), developed lower osmotic potential and maintained higher turgor pressure when osmotically-stressed in solution culture. The ability to adjust osmotically and maintain turgor under drought stress could thus be a useful criterion for the early selection of faster-growing, drought-tolerant genotypes.     

Acute poisoning from gamma-hydroxybutyrate in California.

We report a series of 5 representative patients in California who experienced adverse reactions from the illicitly marketed substance gamma-hydroxybutyrate (GHB). The drug is a putative neurotransmitter marketed as a growth hormone releaser for bodybuilders. The most commonly reported symptoms included abrupt drowsiness, dizziness, and a "high". Other effects were headache, nausea, vomiting, myoclonic jerking, and short-term coma. There have been no reported deaths. If product use is discontinued, full recovery with no long-term side effects is universal. No clear dose-response effect was observed; this may be attributable to differences in susceptibility, wide variations in doses taken by the same person, or the coingestion of other substances. Case interviews confirm that, despite being banned by the US Food and Drug Administration, GHB is still widely available in the underground drug market. Athletes and bodybuilders may take drugs for which there are claims of improved performance or body image. Physicians should be alert for signs of GHB poisoning in emergency department and clinic patients.     

Fine needle aspiration biopsy of hepatocellular carcinoma. Some unusual features.

The cytologic features of fine needle aspiration smears from 28 hepatocellular carcinomas (HCC) were reviewed. All aspirations except one were guided. There were 14 well-, 11 moderately and 3 poorly differentiated HCC. The better-differentiated HCC were characterized by similarity of the tumor cells to hepatocytes (83%), cohesive cell clusters with a trabecular arrangement (72%) and presence of sinusoidal endothelial cells (66%). Other features included bile production (38%), atypical hepatocytic naked nuclei (52%), acinar formation (31%), intracytoplasmic vacuoles (14%) and abnormal vascular patterns (14%). Poorly differentiated HCC showed dyshesive pleomorphic cells. Unusual cytologic features from a well-differentiated HCC with fatty change and an HCC with a prominent acinar component are described. The identification of fatty change in dissociated well-differentiated hepatocytes or cytologic features suggestive of an adenocarcinoma do not preclude the diagnosis of HCC. The usefulness of cell blocks is emphasized.     

Effect of sodium chloride on transport of bacteria in a saturated aquifer material.

Determinations were made of the influence of NaCl concentration, cell density, and flow velocity on the transport of Pseudomonas sp. strain KL2 through columns of aquifer sand under saturated conditions. A pulse-type boundary condition was used. The experiments were conducted by using 0.3-m-long Plexiglas columns with an internal diameter of 0.05 m. When a 1-h pulse of a 0.01 M NaCl solution containing 10(8) cells per ml was added at a flow rate of 10(-4) m s-1, the bacterial density in the effluent never exceeded 2.2% of the density of cells added, and only 1.5% of the bacteria passed through the aquifer material. In contrast, when the bacteria were applied in distilled water, the relative cell density in the effluent approached 100%, and 60% of the bacteria were transported through the aquifer solids. Under these conditions, the breakthrough of Pseudomonas sp. strain KL2 was slower than chloride. When the flow rate was 2.0 x 10(-4) m s-1, the cell density in the effluent reached 7.3% of that added in 0.01 M NaCl solution, but only 3.9% of the bacteria were transported through the aquifer particles. On the other hand, the density in the effluent approached 100% of that added in deionized water, and 77% of the added bacteria were recovered. When the density of added cells was 10(9) cells per ml at a flow rate of 10(-4) m s-1, the densities in the effluent reached 70 and 100% of those added in salt solution and deionized water, respectively, and 44 and 57% of the bacteria were transported through the aquifer solids.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fidelity of mammalian DNA replication and replicative DNA polymerases.

Current models suggest that two or more DNA polymerases may be required for high-fidelity semiconservative DNA replication in eukaryotic cells. In the present study, we directly compare the fidelity of SV40 origin-dependent DNA replication in human cell extracts to the fidelity of mammalian DNA polymerases alpha, delta, and epsilon using lacZ alpha of M13mp2 as a reporter gene. Their fidelity, in decreasing order, is replication greater than or equal to pol epsilon greater than pol delta greater than pol alpha. DNA sequence analysis of mutants derived from extract reactions suggests that replication is accurate when considering single-base substitutions, single-base frameshifts, and larger deletions. The exonuclease-containing calf thymus DNA polymerase epsilon is also highly accurate. When high concentrations of deoxynucleoside triphosphates and deoxyguanosine monophosphate are included in the pol epsilon reaction, both base substitution and frameshift error rates increase. This response suggests that exonucleolytic proofreading contributes to the high base substitution and frameshift fidelity. Exonuclease-containing calf thymus DNA polymerase delta, which requires proliferating cell nuclear antigen for efficient synthesis, is significantly less accurate than pol epsilon. In contrast to pol epsilon, pol delta generates errors during synthesis at a relatively modest concentration of deoxynucleoside triphosphates (100 microM), and the error rate did not increase upon addition of adenosine monophosphate. Thus, we are as yet unable to demonstrate that exonucleolytic proofreading contributes to accuracy during synthesis by DNA polymerase delta. The four-subunit DNA polymerase alpha-primase complex from both HeLa cells and calf thymus is the least accurate replicative polymerase. Fidelity is similar whether the enzyme is assayed immediately after purification or after being stored frozen.(ABSTRACT TRUNCATED AT 250 WORDS)     

Permanent Stained Preparations of Synovial Fluid for Detection of Calcium Compounds Using Alizarin Red S

Permanent preparations of air dried synovial fluids were prepared by staining calcium compounds with alizarin red S stain; each slide was coverslipped with Permount. Variables studied were: (a) concentration of the solution of alizarin red S, (b) pH of staining solution, (c) time of incubation in staining solution and aqueous and ethanolic content of staining solution. The staining effect of each solution was tested on calcium pyrophosphate dihydrate, calcium oxalate, apatite and monosodium urate (MSU). Of all the solutions, best results were obtained with 0.25% alizarin red S in 50% ethanol at pH 7.0 for 30 min. With this solution, the calcium-containing compounds were well stained. MSU did not stain and still preserved negative birefringence on polarizaton. Fixation of smears with ethanol served a double purpose: It fixed the slides without dissolving or removing MSU or the calcium compounds, yet it did dissolve five corticosteroids commonly used for intra-articular injection which may interfere with interpretation of compensated polarized light microscopy of synovial fluids.     

中国野生牡丹研究（一）芍药属牡丹组新分类群

牡丹为我国特产珍贵花树和药用树种,已有1500余年栽培历史,建国以来,各地栽培品种已达500余个。 有关牡丹分类的主要研究成果多为西方科学家根据18—19世纪从我国引种到英、美、法等国的栽培牡丹和腊叶标本加以描述和定名。 作者近几年来在安徽、河南、湖南、山西、陕西、甘肃、四川、云南等地对我国野生牡丹进行了较广泛的调查和研究。 本文发表3个新种和1个新等级,这对研究我国栽培牡丹的起源和栽培品种的自然分类,发掘、保护、利用我国珍稀野生牡丹基因资源,培育新品种,扩大牡丹栽培地区等方面提供了科学理论依据。