Ca2+, annexins, and GTP modulate exocytosis from maize root cap protoplasts

Protoplasts isolated from root cap cells of maize were shown to secrete fucose-rich polysaccharides and were used in a patch-clamp study to monitor changes in whole-cell capacitance. Ca2+ was required for exocytosis, which was measured as an increase in cell capacitance during intracellular dialysis with Ca2+ buffers via the patch pipette. Exocytosis was stimulated significantly by small increases above normal resting [Ca2+]. In the absence of Ca2+, protoplasts decreased in size. In situ hybridization showed significant expression of the maize annexin p35 in root cap cells, differ-entiating vascular tissue, and elongating cells. Dialysis of protoplasts with maize annexins stimulated exocytosis at physiological [Ca2+], and this could be blocked by dialysis with antibodies specific to maize annexins. Dialysis with milli-molar concentrations of GTP strongly inhibited exocytosis, causing protoplasts to decrease in size. GTPgammaS and GDPbetaS both caused only a slight inhibition of exocytosis at physiological Ca2+. Protoplasts were shown to internalize plasma membrane actively. The results are discussed in relation to the regulation of exocytosis in what is usually considered to be a constitutively secreting system; they provide direct evidence for a role of annexins in exocytosis in plant cells.     

长爪沙鼠的遗传多样性分析

利用17个微卫星DNA标记对Z:ZCLA长爪沙鼠封闭群、野生群和近交系进行遗传多样性分析, 评估群体内的遗传变异和群体间的遗传分化。结果表明：在Z:ZCLA封闭群和野生群中共有9个微卫星DNA标记获得稳定的结果, 分别为AF200940、AF200941、AF200942、AF200945、AF200946、AF200947、D11Mit128、PKC和 SCN, 共检测到41个等位基因, 每个基因的等位基因数从1～7不等, 片段大小在120～283 bp之间, 所有位点的平均期望杂合度(He)和多态信息含量(PIC)值分别为0.5032和0.4656, Z:ZCLA封闭群和野生群9个微卫星位点平均有效等位基因数分别为2.78和2.89, 平均基因杂合度分别为0.3704和 0.3893, 平均多态信息含量分别为0.3256和0.3344, 两个群体都表现为中度多态, Z:ZCLA封闭群较野生群稍低; 在3个近交系中共有8个位点获得稳定的扩增结果, 分别为AF200941、AF200942、AF200945、AF200946、AF200947、D11Mit128、PKC和 SCN, 共检测到11个等位基因, 片段大小在140~241 bp之间, 其中5个位点在群体内表现为单态纯合, 3个位点在群体内表现为单态杂合, 所有位点在群体内和群体间均呈单态性, 表明这3个长爪沙鼠品系基本符合近交系的要求, 微卫星标记技术适用于近交系长爪沙鼠的遗传检测。     

Feasibility of breast conservation after neoadjuvant taxene based chemotherapy in locally advanced breast cancer: a Prospective Phase I trial

Background

Acute cholecystitis can be the result of retention of bile in the gallbladder with possible secondary infection and ischaemia. The aim of the present study was to investigate whether internal drainage of the gallbladder could protect against the development of acute cholecystitis in a pig model.

Materials and methods

Twenty pigs were randomized to either internal drainage (drained) or not (undrained). Day 0 acute cholecystitis was induced by ligation of the cystic artery and duct together with inoculation of bacteria. Four days later the pigs were killed and the gallbladders were removed and histologically scored for the presence of cholecystitis. Bile and blood samples were collected for bacterial culturing and biochemical analyses.

Results

The histological examination demonstrated statistical significant differences in acute cholecystitis development between groups, the degree of inflammation being highest in undrained pigs. There were no differences in bacterial cultures between the two groups.

Conclusion

Internal drainage of the gallbladder protected against the development of acute cholecystitis in the present pig model. These findings support the theory that gallstone impaction of the cystic duct plays a crucial role as a pathogenetic mechanism in the development of acute cholecystitis and suggest that internal drainage may be a way to prevent and treat acute cholecystitis.     

Towards a novel laser-driven method of exotic nuclei extraction−acceleration for fundamental physics and technology

A combination of a petawatt laser and nuclear physics techniques can crucially facilitate the measurement of exotic nuclei properties. With numerical simulations and laser-driven experiments we show prospects for the Laser-driven Exotic Nuclei extraction–acceleration method proposed in [M. Nishiuchi et al., Phys, Plasmas 22, 033107 (2015)]: a femtosecond petawatt laser, irradiating a target bombarded by an external ion beam, extracts from the target and accelerates to few GeV highly charged short-lived heavy exotic nuclei created in the target via nuclear reactions.     

Biosynthesis ofL-lysine inCorynebacterium glutamicum on sucrose,ethanol and acetic acid

Production ofL-lysine was followed in two lysine-accumulating mutants ofCorynebacterium glutamicum ATCC 13287 in media containing sucrose, ethanol, acetic acid or a mixture of acetic acid and ammonium or sodium acetate. It was found that acetate is the best substitution for sucrose.     

Involvement of SIK3 in glucose and lipid homeostasis in mice

Salt-inducible kinase 3 (SIK3), an AMP-activated protein kinase-related kinase, is induced in the murine liver after the consumption of a diet rich in fat, sucrose, and cholesterol. To examine whether SIK3 can modulate glucose and lipid metabolism in the liver, we analyzed phenotypes of SIK3-deficent mice. Sik3(-/-) mice have a malnourished the phenotype (i.e., lipodystrophy, hypolipidemia, hypoglycemia, and hyper-insulin sensitivity) accompanied by cholestasis and cholelithiasis. The hypoglycemic and hyper-insulin-sensitive phenotypes may be due to reduced energy storage, which is represented by the low expression levels of mRNA for components of the fatty acid synthesis pathways in the liver. The biliary disorders in Sik3(-/-) mice are associated with the dysregulation of gene expression programs that respond to nutritional stresses and are probably regulated by nuclear receptors. Retinoic acid plays a role in cholesterol and bile acid homeostasis, wheras ALDH1a which produces retinoic acid, is expressed at low levels in Sik3(-/-) mice. Lipid metabolism disorders in Sik3(-/-) mice are ameliorated by the treatment with 9-cis-retinoic acid. In conclusion, SIK3 is a novel energy regulator that modulates cholesterol and bile acid metabolism by coupling with retinoid metabolism, and may alter the size of energy storage in mice.     

Human hepatocyte growth factor in plasma from patients with fulminant hepatic failure

Plasma from patients with fulminant hepatic failure obtained during plasma exchange therapy, like their serum, demonstrated marked stimulatory activity on DNA synthesis in cultured rat hepatocytes. Heat treatment at 56 degrees C for 30 min did not affect this activity of the plasma, but reduced that of the serum. This growth-promoting activity was confirmed by showing that the patients' serum and plasma increased the labeling index with [3H]thymidine and the total number of nuclei in hepatocyte cultures. The activity of pooled active fractions obtained by gel filtration of the heated plasma was lost completely on heat treatment at 80 degrees C for 10 min or on treatment with trypsin or chymotrypsin, which suggests that it was due to a protein. The human hepatocyte growth factor was purified about 600-fold from heated plasma of a patient by ammonium sulfate precipitation and chromatographies on Affi-Gel Blue and hydroxylapatite. The maximum effect of this partially purified factor on DNA synthesis in cultured hepatocytes was greater than that of epidermal growth factor. The molecular weight of the hepatocyte growth factor was about 85,000 as determined by SDS-PAGE.     

Molecular cloning of the gene encoding the mosaic neurotoxin, composed of parts of botulinum neurotoxin types C1 and D, and PCR detection of this gene from Clostridium botulinum type C organisms.

The DNA fragment common to the genes encoding botulinum neurotoxin types C1 (BN/C1) and D (BN/D) was amplified by PCR from the culture supernatant of Clostridium botulinum type C strain 6813 (C6813) that was treated with either DNase I or proteinase K but not from the supernatant that was treated with both DNase I and proteinase K, suggesting the neurotoxin gene is located on a certain bacteriophage DNA. Thus, to isolate the neurotoxin gene, we performed PCR with the culture supernatant of C6813 and seven primer pairs designed from the genes encoding BN/C1 and BN/D. The coding region in the connected sequence encodes a neurotoxin composed of 1,280 amino acids with a molecular weight of 147,817. The neurotoxin from C6813 has 95% amino acid identity to BN/C1, except for its C-terminal one-third, which is quite similar to the C-terminal one-third of BN/D (95% identity). When we performed PCRs with four primer pairs designed from the 5'-terminal two-thirds of the BN/C1 gene and two primers from the 3'-terminal one-third of the BN/D gene, DNA fragments of the expected sizes (0.5 to 1.3 kbp) could be amplified from C. botulinum type C strains 6812 and 6814. These results suggest that some strains of C. botulinum type C contain the gene encoding the mosaic neurotoxin composed of parts of BN/C1 and BN/D.     

A comparison of sciatic nerve neuropathy in diabetic and aged rats

We compared the development of sciatic nerve neuropathy in young diabetic rats with that in non-diabetic aged rats. Diabetes was induced in six-month old rats by injection with alloxan and was moderately controlled by single daily injections of insulin. Blood insulin levels in diabetic rats were significantly reduced compared to the aged animals, and glucose was significantly higher in diabetic rats. Sciatic nerve conduction velocities were measured monthly. Both motor and sensory conduction velocities decreased in the diabetic rats to a level that was similar to those in 36-month old rats. The decreases in conduction velocities in the diabetic rats were most dramatic during months 6 through 12 of diabetes. After 6 and 12 months of diabetes, sciatic nerves were examined by electron microscopy and compared to nerves from 24- and 36-month old rats respectively. Ultrastructural changes in the sciatic nerves of diabetic rats at 6 months included disruptions of myelin and dense axoplasm. In comparison, the 24-month old rats only had distorted contours of the nerve fibres. After 12 months of diabetes, the axoplasm had large spaces and the myelin was thickened and deformed. The axoplasm of 36-month old rats was normal in appearance; however the myelin sheath was thickened and split into layers. The Schwann cells were vacuolated and irregular in shape. These observations indicate that diabetes results in the early onset of age-like changes in the sciatic nerve. It suggests that the control of hyperglycemia in humans may preserve sciatic nerve structure and function.