The long road to understanding the baculovirus P10 protein

The baculovirus P 10 protein has always represented a mystery in the feld of insect virology. Like the baculovirus polyhedrin protein it is expressed at high levels very late in infection. Homologues of the Autographa californica nucleopolyhedrovirus plO gene are conserved in all Alphabaculoviruses and in other viruses of lepidopteran hosts yet is completely dispensable for virus replication and transmission. P10 is a microtubule interacting protein whose expression has been associated with the formation of a variety of complex and extensive cytoplasmic and nuclear structures. P10 has been associated with a number of roles during infection ranging from the formation of virus occlusion bodies, to affecting the rate of cellular and/or nuclear lysis during the final stages of the virus replication cycle. In this article we review recent work aimed at understanding the role of this enigmatic protein, putting them into context with recent advances in understanding of protein structure and function. We look back at a number of historical studies and observations, reanalysing their conclusions based on recent data and our own observations. The role of the P 10 protein during baculovirus replication remains elusive, however, novel avenues of investigation have been identified that will, we are sure, eventually lead to an understanding of this protein.     

High-throughput capillary electrophoresis method for plasma cysteinylglycine measurement: evidences for a clinical application

Summary. Increased levels in plasma homocysteine and cysteine, and more recently, decreased levels in cysteinylglycine have been indicated as a risk factor for vascular diseases. Most assays focused their attention only on homocysteine determination and when also other thiols were measured, analytical times drastically increased. By modifying our previous method for thiols detection, we set up a rapid capillary electrophoresis method for the selective quantification of plasma cysteinylglycine, cutting the analysis time of about 50%. Samples were treated with tri-n-butylphosphine as reducing agent, proteins were precipitated with trichloroacetic acid and released thiols were successively derivatized by the selective thiol laser-induced fluorescence-labeling agent 5-iodoacetamidofluorescein and separated by capillary electrophoresis. A baseline separation between peaks was obtained in about 2 min using 3 mmol/L sodium phosphate/2.5 mmol/L boric acid as electrolyte solution with 75 mmol/L N-methyl-D-glucamine at pH 11.25 in a 47 cm long capillary with a cartridge temperature of 45 °C. The method application was checked by measuring plasma Cys-Gly levels in a group of patients affected by retinal vein occlusion (RVO), an important cause of visual loss in the elderly. The low levels of Cys-Gly found in the RVO patients suggest that these small thiols may have importance in the disease development. Authors’ addresses: Dr. Angelo Zinellu, Dr. Ciriaco Carru, Department Biomedical Sciences, Chair of Clinical Biochemistry, University of Sassari, Viale San Pietro 43/B, 07100 Sassari, Italy     

Spatial regulation of cytokinesis in bacteria

Cytokinesis in bacteria such as Escherichia coli is orchestrated by FtsZ, a tubulin-like protein that forms a circumferential Z ring at the division site. The Z ring then recruits a number of other essential cell division proteins, ultimately assembling the cytokinetic machine that splits the cell. It has been known for some time that the MinCDE proteins and the bacterial nucleoid provide positional information to negatively regulate cytokinesis. Recently, direct visualization of Z rings and Min proteins in whole cells have contributed important new insights into the molecular mechanisms behind this fundamental cellular process. This review summarizes and integrates these insights.     

氧化应激对溶酶体储存与转运甲醛的影响

内源甲醛代谢失调被认为是导致阿尔茨海默病的危险因素之一,甲醛蓄积会引起神经细胞的死亡和认知功能的降低.研究表明,细胞内甲醛分布于溶酶体内,而溶酶体功能异常与神经退行性疾病密切相关.本文采用甲醛特异荧光探针,在氧化应激条件下,检测到小鼠脑微血管内皮细胞株bEnd.3和小鼠神经瘤母细胞株N2a溶酶体内甲醛明显升高;在慢性脑低灌注大鼠动物模型中,其脑神经细胞的溶酶体内甲醛也升高(P0.01);LeuLeuOMe处理bEnd.3细胞,使其溶酶体膜通透性增加,导致细胞内甲醛蓄积,而胞外甲醛降低.以上结果证明,溶酶体具有储存和转运甲醛的功能,如果溶酶体出现结构与功能的异常,会导致甲醛代谢失调,造成认知损害.     

Diversity and convergences in the evolution of feeding adaptations in ankylosaurs (Dinosauria: Ornithischia)*

Ankylosaurian dinosaurs were low-browsing quadrupeds that were traditionally thought of as simple orthal pulpers exhibiting minimal tooth occlusion during feeding, as in many extant lizards. Recent studies, however, have demonstrated that effective chewing with tooth occlusion and palinal jaw movement was present in some members of this group. Qualitative and quantitative analysis of feeding characters (i.e. craniodental features, tooth wear patterns, origin and insertion of jaw adductors) reveal at least three different jaw mechanisms during the evolution of Ankylosauria. Whereas, in basal members, food processing was restricted to simple orthal pulping, in late Early and Late Cretaceous North American and European forms a precise tooth occlusion evolved convergently in many lineages (including nodosaurids and ankylosaurids) complemented by palinal power stroke. In contrast, Asian forms retained the primitive mode of feeding without any biphasal chewing, a phenomenon that might relate to the different types of vegetation consumed by these low-level feeders in different habitats on different landmasses. Further, a progressive widening of the muzzle is demonstrated both in Late Cretaceous North American and Asian ankylosaurs, and the width and general shape of the muzzle probably correlates with foraging time and food type, as in herbivorous mammals.     

The effects of nifedipine on respiratory mechanics investigated by theend-inflation occlusion method in the rat

Context: Calcium channel blockers may theoretically exhibit relaxing effects not only on vascular smooth muscle but also on airway smooth muscle.

Objective: To investigate possible effects of nifedipine on respiratory mechanics in the rat.

Methods: Respiratory system mechanical parameters were measured by the end-inflation occlusion method in the rat in vivo before and after the intraperitoneal administration of nifedipine.

Results: We found that nifedipine affects respiratory mechanics, inducing a reduction of airway resistance and of respiratory system elastance, probably because of a relaxing action on airway and parenchimal smooth muscle cells.

Conclusion: Should these results be further confirmed by human investigations, a possible role of nifedipine in pharmacological respiratory system’s diseases treatment may be suggested.     

The damage-associated molecular pattern HMGB1 is released early after clinical hepatic ischemia/reperfusion

Objective and backgroundActivation of sterile inflammation after hepatic ischemia/reperfusion (I/R) culminates in liver injury. The route to liver damage starts with mitochondrial oxidative stress and cell death during early reperfusion. The link between mitochondrial oxidative stress, damage-associate molecular pattern (DAMP) release, and sterile immune signaling is incompletely understood and lacks clinical validation. The aim of the study was to validate this relation in a clinical liver I/R cohort and to limit DAMP release using a mitochondria-targeted antioxidant in I/R-subjected mice.MethodsPlasma levels of the DAMPs high-mobility group box 1 (HMGB1), mitochondrial DNA, and nucleosomes were measured in 39 patients enrolled in an observational study who underwent a major liver resection with (N = 29) or without (N = 13) intraoperative liver ischemia. Circulating cytokine and neutrophil activation markers were also determined. In mice, the mitochondria-targeted antioxidant MitoQ was intravenously infused in an attempt to limit DAMP release, reduce sterile inflammation, and suppress I/R injury.ResultsIn patients, HMGB1 was elevated following liver resection with I/R compared to liver resection without I/R. HMGB1 levels correlated positively with ischemia duration and peak post-operative transaminase (ALT) levels. There were no differences in mitochondrial DNA, nucleosome, or cytokine levels between the two groups. In mice, MitoQ neutralized hepatic oxidative stress and decreased HMGB1 release by ±50%. MitoQ suppressed transaminase release, hepatocellular necrosis, and cytokine production. Reconstituting disulfide HMGB1 during reperfusion reversed these protective effects.ConclusionHMGB1 seems the most pertinent DAMP in clinical hepatic I/R injury. Neutralizing mitochondrial oxidative stress may limit DAMP release after hepatic I/R and reduce liver damage.