A new Salmonella serovar S.III b 58:z10:z53:Rz50

A new Salmonella serovar S.III b 58:z10:z53:Rz50 was isolated from the water samples of Ashida river, Fukuyama city, Japan. Its antigenic structure is described.     

EHEC O157:H7 z3276基因缺失株构建及其生物学特性

【目的】肠出血性大肠杆菌O157:H7是世界范围内重要的动物源性致病菌之一,可感染人。I型菌毛是多种致病性大肠杆菌(如肾盂肾炎型大肠杆菌等)可表达的一种黏附结构,与细菌吸附黏膜表面密切相关。然而,O157:H7 fim操纵子上几个核苷酸的缺失却导致其不能表达I型菌毛。BLAST比对结果表明O157:H7独有的开放阅读框z3276编码的氨基酸序列与其他大肠杆菌I型菌毛高度同源,这可能是对O157:H7不能表达I型菌毛的补偿机制,但确切功能尚不清楚。本文探究z3276基因的生物学功能。【方法】利用O157:H7 86-24参考菌株构建z3276基因缺失株(?z3276),并构建其互补株(C?z3276),进而比较亲本株、?z3276与C?z3276的生物学特性及对小鼠致病性差异。【结果】与亲本株相比,?z3276进入对数生长期的时间延后,在半固体琼脂平板上的迁移直径明显缩小,生物被膜形成能力显著减弱。?z3276对HEp-2细胞的黏附和侵袭能力并无明显变化,但对IPEC-J2细胞的侵袭能力明显减弱。在小鼠攻毒试验中,?z3276组排菌数量减少、排菌持续时间缩短。C?z3276各项特性均能回复到与亲本株一致的水平。【结论】z3276基因可能是O157:H7重要的毒力相关因子。     

沙门氏菌Ⅲb的一个新血清型

1989年8月从蛇肠内容物中检出一株沙门氏菌,编号为S.3337经鉴定为新血清型,其生化特性符合沙门氏菌属的定义.根据该菌株不发酵卫矛醇,能利用丙二酸盐,迅速发酵乳糖,ONPG为阳性,具有双相H抗原,应归属于沙门氏菌Ⅲb.经抗原分析该菌株的抗原式为65:z:z_(55).     

A linear plasmid truncation induces unidirectional flagellar phase change in H:z66 positive Salmonella Typhi

The process by which bacteria regulate flagellar expression is known as phase variation and in Salmonella enterica this process permits the expression of one of two flagellin genes, fliC or fljB, at any one time. Salmonella Typhi (S. Typhi) is normally not capable of phase variation of flagellar antigen expression as isolates only harbour the fliC gene (H:d) and lacks an equivalent fljB locus. However, some S. Typhi isolates, exclusively from Indonesia, harbour an fljB equivalent encoded on linear plasmid, pBSSB1 that drives the expression of a novel flagellin named H:z66. H:z66+S. Typhi isolates were stimulated to change flagellar phase and genetically analysed for the mechanism of variation. The phase change was demonstrated to be unidirectional, reverting to expression from the resident chromosomal fliC gene. DNA sequencing demonstrated that pBSSB1 linear DNA was still detectable but that these derivatives had undergone deletion and were lacking fljA(z66) (encoding a flagellar repressor) and fljB(z66). The deletion end-point was found to involve one of the plasmid termini and a palindromic repeat sequence within fljB(z66), distinct to that found at the terminus of pBSSB1. These data demonstrate that, like some Streptomyces linear elements, at least one of the terminal inverted repeats of pBSSB1 is non-essential, but that a palindromic repeat sequence may be necessary for replication.     

Radioreceptor assay in checking serum concentration in long-term treatment with cis(z)-flupenthixol decanoate

24 patients have been treated with cis(z)-flupenthixol decanoate for 6-12 months. Intramuscular injections were given about every 3 weeks. Before treatment and on each day of injection the mental state was assessed by BPRS and registration of side effects was performed. Blood samples were taken 7 days after each injection and on the last day of the dosage interval. Neuroleptic activity was determined in serum by RRA and expressed in cis(z)-flupenthixol equivalents. The drug level was significantly correlated to the dose. No clear relationship between drug level and clinical results as well as side effects was found. Less pronounced variations of the drug level between subsequent injections resulted in a positive therapeutic response.     

New feather mites of the Nycteridocaulus generic group (Acariformes: Proctophyllodidae) from passerines (Passeriformes) in Panama

Systematic Parasitology - Three new feather mite species of the Nycteridocaulus generic group (Proctophyllodidae: Proctophyllodinae) are described from passerines in Panama: Atrichophyllodes...     

An integrative approach to reveal speciation and species richness in the genus Diasporus (Amphibia: Anura: Eleutherodactylidae) in eastern Panama

We have applied an integrative taxonomic approach, including bioacoustics, ecology, morphology, and molecular genetics (barcoding and phylogeography), to explore species richness in the genus Diasporus in eastern Panama, from where only Diasporus quidditus (Lynch, 2001) was previously known. During fieldwork in eastern Panama in 2011 and 2012 we found six additional species, four of which we are describing here as new to science, plus two species that are new for this region. We have evaluated the presence of Diasporus diastema (Cope, 1875) in eastern Panama by comparing morphological, genetic, and bioacoustic characters of specimens from near the type locality in central Panama with specimens from eastern Panama. We further describe and compare male advertisement calls of most Diasporus species. The phylogeographic analysis suggests the allopatric speciation of Diasporus species in eastern Panama following the completion of the Panamanian isthmus in the middle Miocene. Subsequent geological events concur with the vicariant evolution of different lineages in situ, suggesting eastern Panama to be a centre of endemism for this group of frogs. We present an integrative analysis of the species from eastern Panama and include an identification key for all species of the genus.     

Cloning and characterization of the gene encoding the z66 antigen of Salmonella enterica serovar Typhi

Z66 antigen-positive strains of Salmonella enterica serovar Typhi change flagellin expression in only one direction from the z66 antigen to the d or j antigen, which is different from the phase variation of S. enterica serovar Typhimurium. In the present study, we identified a new flagellin gene in z66 antigen-positive strains of S. enterica serovar Typhi. The genomic structure of the region containing this new flagellin gene was similar to that of fljBA operon of biphasic S. enterica serovars. A fljA-like gene was present downstream of the new flagellin gene. A rho-independent terminator was located between the new flagellin gene and the fljA-like gene. Hin-like gene was not present upstream of the new flagellin gene. We generated a mutant strain of S. enterica serovar Typhi, which carries a deletion of the new flagellin gene. Western blotting revealed that the 51-kDa z66 antigen protein was absent from the population of proteins secreted by the mutant strain. Southern hybridization demonstrated that the z66 antigen-positive strains of S. enterica serovar Typhi carried the new flagellin gene and fliC on two different genomic EcoRI fragments. When z66 antigen-positive strains were incubated with anti-z66 antiserum, the flagellin expression by S. enterica serovar Typhi changed from z66 antigen to j antigen. The new flagellin gene and the fljA-like gene were absent in the strain with altered flagellin expression. These results suggested that the new flagellin gene is a fljB-like gene, which encodes the z66 antigen of S. enterica serovar Typhi, and that deletion of fljBA-like operon may explain why S. enterica serovar Typhi alters the flagellin expression in only one direction from the z66 antigen to the d or j antigen.     

Coupling of the muscarinic m2 receptor to G protein-activated K(+) channels via Galpha(z) and a receptor-Galpha(z) fusion protein. Fusion between the receptor and Galpha(z) eliminates catalytic (collision) coupling

G protein-activated K(+) channel (GIRK), which is activated by the G(betagamma) subunit of heterotrimeric G proteins, and muscarinic m2 receptor (m2R) were coexpressed in Xenopus oocytes. Acetylcholine evoked a K(+) current, I(ACh), via the endogenous pertussis toxin (PTX)-sensitive G(i/o) proteins. Activation of I(ACh) was accelerated by increasing the expression of m2R, suggesting a collision coupling mechanism in which one receptor catalytically activates several G proteins. Coexpression of the alpha subunit of the PTX-insensitive G protein G(z), Galpha(z), induced a slowly activating PTX-insensitive I(ACh), whose activation kinetics were also compatible with the collision coupling mechanism. When GIRK was coexpressed with an m2R x Galpha(z) fusion protein (tandem), in which the C terminus of m2R was tethered to the N terminus of Galpha(z), part of I(ACh) was still eliminated by PTX. Thus, the m2R of the tandem activates the tethered Galpha(z) but also the nontethered G(i/o) proteins. After PTX treatment, the speed of activation of the m2R x Galpha(z)-mediated response did not depend on the expression level of m2R x Galpha(z) and was faster than when m2R and Galpha(z) were coexpressed as separate proteins. These results demonstrate that fusing the receptor and the Galpha strengthens their coupling, support the collision-coupling mechanism between m2R and the G proteins, and suggest a noncatalytic (stoichiometric) coupling between the G protein and GIRK in this model system.     

On the value of knowing a z* ion for what it is

Computer simulation of database searches of electron transfer dissociation (ETD) spectra using both "bottom up" and "top down" approaches was performed to evaluate the utility of knowing a priori which product ions contain the C-terminus (i.e., the z* ions). In this work, knowledge of the identities of the z* ions was used to exclude putative identifications that are based solely on the mass matching of undifferentiated product ions derived from an experiment with those derived from in silico fragmentation. The benefit from knowing which ions are z* ions was found to be heavily dependent on the quality of the ETD spectra, in terms of sequence coverage afforded by the product ions, the amount of noise in the spectra (i.e., extraneous peaks that do not directly reflect primary structure), and mass measurement accuracy. Under conditions in which the likelihood for misidentifications are high without a priori knowledge of ion types (e.g., b-, y-, c-, or z-ions), a knowledge of which product ions are z* ions allows discrimination against false-positive identifications. Relatively little benefit from knowing which ions are z* ions was noted when product spectra reflected relatively high sequence coverage and when a low fraction of the products ions were due to extraneous peaks (i.e., spectra with relatively little noise). In all cases, specificity is higher with higher mass measurement accuracy with the consequent reduction in benefit from knowledge of which ions are z* ions.     

Transcriptional expression of fljB:z66, a flagellin gene located on a novel linear plasmid of Salmonella enterica serovar Typhi under environmental stresses

A previous study identified that z66+ strain of Salmonella enterica serovar Typhi contains two different flagellin genes, the fliC encoding d or j antigen in chromosome and the fljB-like gene encoding z66 antigen in a novel linear plasmid, respectively. The promoter of fljB:z66 is different from that of fliC:d/j and z66+ strain alters flagellin expression in only one orientation, from z66 to d orj antigen, raising the suspicion that z66+ strain is a special biphasic strain. To clarify the expressional characteristics of flagellin genes of z66+ strain, expression patterns of fljB:z66 and fliC were investigated by RT-PCR under a series of environmental stresses during infection, such as acidic stress, osmotic stress, bile acid stress and oxidative stress. Results showed that the expression level of fljB:z66 is over 10-fold higher than the level of fliC in low and middle osmotic conditions before stresses. Only the expressional regulatory tendency of fljB:z66 in response to bile acid stress is similar to that of fliC. Differential expressional patterns between fljB:z66 and fliC of S. enterica serovar Typhi were seen under osmotic stress, bile acid stress and oxidative stress. These results support the hypothesis that the z66+ strain is a special biphasic strain of S. enterica serovar Typhi.     

The G alpha z gene product in human erythrocytes. Identification as a 41-kilodalton protein

A cDNA encoding a previously unknown G protein alpha-subunit lacking the site for pertussis toxin-catalyzed ADP-ribosylation was recently cloned and its putative protein product named Gz (Fong, H. K. W., Yoshimoto, K. K., Eversole-Cire, P., and Simon, M. I. (1988) Proc. Natl. Acad. Sci. U. S. A. 85, 3066-3070) or Gx (Matsuoka, M., Itoh, H. Kozasa, T., and Kaziro, Y. (1988) Proc. Natl. Acad. Sci. U. S. A. 85, 5384-5388). A synthetic peptide corresponding to the deduced carboxyl-terminal decapeptide of this putative protein (alpha z) has been synthesized and used to prepare a polyclonal rabbit antiserum directed against the protein. The specificity and cross-reactivity of this antiserum was assessed using bacterially expressed recombinant G protein alpha-subunit fusion proteins (r alpha). The crude antiserum strongly recognizes r alpha z in immunoblots. Pretreatment of antiserum with antigen peptide greatly reduces the interaction of the antiserum with r alpha z. Affinity purified antiserum strongly recognizes expressed r alpha z, does not recognize r alpha s1, r alpha s1, r alpha o, or r alpha i3, and very weakly interacts with r alpha i1 and r alpha i2. In contrast, the alpha-subunits of purified bovine brain Gi1 and human erythrocyte Gi2 and Gi3 did not react with the alpha z-antiserum. Partially purified mixtures of human erythrocyte G proteins contain a 41-kDa protein that reacts specifically in immunoblots with both crude and affinity purified alpha z-specific antiserum. Quantitative immunoblotting using r alpha z as a standard indicates that there is 60-100 ng of alpha z/micrograms of 40/41-kDa alpha-subunit protein in partially purified human erythrocyte G protein preparations. We conclude that we have identified the alpha z gene product as a 41-kDa trace protein in human erythrocytes.     

Report of Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae: Phlebotominae) in a cutaneous-leishmaniasis-endemic area of Panama

Lutzomyia longipalpis is the primary vector of the parasite responsible for visceral leishmaniasis in the Americas. In the present study, Lu. longipalpis was found in a domiciliary area in Limón, a district in Capira, a region in which cutaneous leishmaniasis is endemic in Panama. Previously, this species has been found in a humid forest in this same region. Finding Lu. longipalpis in domiciliary areas indicates that this species may be adapting to new habitats and that it may play a role in the transmission of leishmaniasis in Panama.     

Histone H2A.z is essential for cardiac myocyte hypertrophy but opposed by silent information regulator 2alpha

In this study we have shown that the histone variant H2A.z is up-regulated during cardiac hypertrophy. Upon its knock-down with RNA interference, hypertrophy and the underlying increase in growth-related genes, protein synthesis, and cell size were down-regulated. During attempts to understand the mode of regulation of H2A.z, we found that overexpression of silent information regulator 2alpha (Sir2alpha) specifically induced down-regulation of H2A.z via NAD-dependent activity. This effect was reversed by the proteasome inhibitor epoxomicin, suggesting a Sir2alpha-mediated ubiquitin/proteasome-dependent mechanism for degradation of H2A.z. An increase in Sir2alpha also resulted in a dose-dependent reduction of the response to hypertrophic stimuli, whereas its inhibition resulted in enhanced hypertrophy and apoptosis. We have shown that Sir2alpha directly deacetylates H2A.z. Mutagenesis proved that lysines 4, 7, 11, and 13 do not play a role in the stability of H2A.z, whereas Lys-15 was indispensable. Meanwhile, Lys-115 and conserved, ubiquitinatable Lys-121 are critical for Sir2alpha-mediated degradation. Fusion of the C terminus of H2A.z (amino acids 115-127) to H2A.x or green fluorescence protein conferred Sir2alpha-inducible degradation to the former protein only. Because H2A.x and H2A.z have conserved N-tails, this implied that both the C and N termini are critical for mediating the effect of Sir2alpha. In short, the results suggest that H2A.z is required for cardiac hypertrophy, where its stability and the extent of cell growth and apoptosis are moderated by Sir2alpha. We also propose that Sir2alpha is involved in deacetylation of H2A.z, which results in ubiquitination of Lys-115 and Lys-121 and its degradation via a ubiquitin/proteasome-dependent pathway.     

The ethnobotany ofCarludovica palmata Ruíz & Pavón (Cyclanthaceae) in Amazonian Ecuador

All of Ecuador’s indigenous Amazonian people use Carludovica palmata Ruíz & Pavón. The most frequent use is for roof thatching. Fibers from the petiole also are used to make baskets and to tie small timbers. The Shuar, Achuar and Quichua make mammal and fish traps from the petiole. The bases of unopened leaf buds and the fruits are edible. The buds have a taste similar to palm hearts. Carludovica palmata grows in open, disturbed sites often in alluvial soil. Ecuador’s indigenous people often protect the plant when clearing fields. They also intentionally plant it. The commercial use of its buds for food and the marketing of native crafts made from C. palmata could rival the plant’s importance in the Panama hat industry.     

Illustration of SSMD, z score, SSMD*, z* score, and t statistic for hit selection in RNAi high-throughput screens

Hit selection is the ultimate goal in many high-throughput screens. Various analytic methods are available for this purpose. Some commonly used ones are z score, z* score, strictly standardized mean difference (SSMD), SSMD*, and t statistic. It is critical to know how to use them correctly because the misusage of them can readily produce misleading results. Here, the author presents basic concepts, elaborates their commonality and difference, describes some common misusage that people should avoid, and uses simulated simple examples to illustrate how to use them correctly.     

过表达DNALI1抑制低氧环境中鼻咽癌细胞株CNE-2z侵袭与迁移

目的探讨模拟肿瘤内低氧微环境下，动力蛋白轴突轻链中间体1 （DNALI1）对鼻咽癌细胞株CNE-2z增殖、迁移、侵袭和凋亡的影响。 方法R语言软件分析GEO数据库中鼻咽癌组织的3个数据集，分析其差异基因（DEGs）。低氧是肿瘤微环境基本特征，体外细胞研究均在低氧工作站（1﹪O₂）中进行，以模拟体内低氧微环境。将DNALI1过表达质粒和空载体质粒包装成慢病毒后感染CNE-2z细胞，构建DNALI1基因稳定过表达的CNE-2z细胞株。将CNE-2z细胞分别进行正常培养（空白对照，BC），感染空载体慢病毒（阴性对照，NC）和感染过表达DNALI1慢病毒（过表达DNALI1，DNALI1-OE）。实时荧光定量聚合酶链式反应（RT-qPCR）和Western blot检测DNALI1 mRNA和蛋白表达水平；集落形成实验检测细胞增殖能力；Transwell实验检测细胞迁移和侵袭能力；流式细胞术检测细胞凋亡水平。多组间比较采用单因素方差分析，组间两两比较采用LSD-t检验。 结果生物信息学分析发现，与健康人鼻咽组织相比，鼻咽癌组织中DNALI1基因低表达。在低氧环境中，BC组与NC组细胞增殖、凋亡、迁移和侵袭比较，差异均无统计学意义；与BC组和NC组比较，DNALI1-OE组细胞增殖能力和凋亡水平比较，差异均无统计学意义（P均> 0.05）。与BC组和NC组比较，DNALI1-OE组细胞迁移能力[（198.67±3.22），（199.00±3.00）比（75.00±7.55）个]和侵袭能力[（240.67±16.01），（259.67±3.06）比（83.33±9.50）个]降低，差异具有统计学意义（P均< 0.001）。 结论低氧环境中，DNALI1过表达可抑制CNE-2z细胞侵袭与迁移能力，但对细胞增殖、凋亡无明显影响。     

Lac z Histochemistry and immunohistochemistry reveal ephrin-B ligand expression in the inner ear.

Immunostaining in transgenic mice carrying the lac z gene can be used to map gene and protein distribution in a single tissue. In this study, we examined inner ears from ephrin-B3 homozygous and ephrin-B2 heterozygous mice. Ephrin-B3 lac z expression was limited in these mice. However, immunostaining revealed ephrin-B3 throughout cochlear and vestibular regions. Immunoreactivity was absent in ephrin-B3-homozygous null mutants, demonstrating the specificity of the antibody. Ephrin-B2 lac z reactivity was detected in a limited number of cells in cochlear and vestibular regions. Different immunostaining patterns were found with different antibodies. Comparison with lac z expression indicated which antibody was specific for the transmembrane-bound ephrin-B2 ligand.