Purkyn? cells and Betz cells

J.E. Purkyn? was the first to discover, by achromatic microscopy of stained and fixed as well as of fresh material, that animal tissues in general, and those of the central nervous system in particular, are made up of cells, as are those of plants. His discoveries laid the foundations of modern research on the ultrastructure and biophysies of the cerebellar neurons which bear his name, as well as on other types of neurons, in vitro as well as in vivo.     

Genetic networks regulated by ASYMMETRIC LEAVES1 (AS1) and AS2 in leaf development in Arabidopsis thaliana: KNOX genes control five morphological events

The asymmetric leaves 1 ( as1 ) and as2 mutants of Arabidopsis thaliana exhibit pleiotropic phenotypes. Expression of a number of genes, including three class-1 KNOTTED -like homeobox ( KNOX ) genes ( BP , KNAT2 and KNAT6 ) and ETTIN / ARF3 , is enhanced in these mutants. In the present study, we attempted to identify the phenotypic features of as1 and as2 mutants that were generated by ectopic expression of KNOX genes, using multiple loss-of-function mutations of KNOX genes as well as as1 and as2 . Our results revealed that the ectopic expression of class-1 KNOX genes resulted in reductions in the sizes of leaves, reductions in the size of sepals and petals, the formation of a less prominent midvein, the repression of adventitious root formation and late flowering. Our results also revealed that the reduction in leaf size and late flowering were caused by the repression, by KNOX genes, of a gibberellin (GA) pathway in as1 and as2 plants. The formation of a less prominent midvein and the repression of adventitious root formation were not, however, related to the GA pathway. The asymmetric formation of leaf lobes, the lower complexity of higher-ordered veins, and the elevated frequency of adventitious shoot formation on leaves of as1 and as2 plants were not rescued by multiple mutations in KNOX genes. These features must, therefore, be controlled by other genes in which expression is enhanced in the as1 and as2 mutants.     

Hereditary defects in both germ cells and the blood-testis barrier system in as-mutant rats: evidence from spermatogonial transplantation and tracer-permeability analysis

The rat mutant allele as is located on chromosome 12. Homozygous (as/as) males show arrested spermatogenesis, mainly at the pachytene spermatocyte stage. It is not clear whether this defective spermatogenesis is caused by a failure in a somatic cell component that supports spermatogenesis or in the germ cell itself. Spermatogonial transplantation was performed to identify the genetically defective site in the as/as testis. In experiment 1, germ cells collected from as/as testes were transplanted into the testes of immunodeficient mice and normal rats. In experiment 2, normal rat germ cells were transplanted into as/as testes. The results of experiment 1 showed arrest of spermatogenesis at the pachytene spermatocyte stage, accompanied by a characteristic morphological feature, i.e., the formation of inclusion-like bodies in the cytoplasm, in both rat and mouse recipients. These results revealed the intrinsic effect of the mutant gene(s) on germ cells. In experiment 2, no restoration of spermatogenesis was detected in the recipient testes despite thorough histological examination. These results suggest that defects in a somatic cell component in as/as testes prevent the donor germ cells from colonizing and regaining their spermatogenetic ability. When the seminiferous epithelium of the as/as testis was examined by electron microscopy, no morphological abnormalities, including the formation of ectoplasmic specializations between adjacent Sertoli cells, were observed in the somatic cell components. However, when cytochrome c was applied as a tracer material, it penetrated the tight junctions between the Sertoli cells, indicating dysfunction of the blood-testis barrier in the as/as testis. The lack of restoration of spermatogenesis in the as/as testis after transplantation of normal germ cells may have been caused by the unfavorable environment in the seminiferous epithelium resulting from the incomplete barrier system between adjoining Sertoli cells. The gene(s) at the as locus may have a role in both germ cell differentiation and the establishment of the blood-testis barrier.     

Biochemical mechanism of combined effect of ethambutol and sparfloxacin against Mycobacterium smegmatis

M. smegmatis cells grown in the presence of combination of ethambutol (EMB) and sparfloxacin (SPX) had decreased level of total cellular lipids as compared to control as well as cells grown in the presence of sub-inhibitory concentration (MIC50) of individual drugs. Amongst various phospholipids analyzed, maximum decrease was observed in the content of phosphatidylinositolmannosides (PIMs) of the cells grown in combination of EMB and SPX. In contrast, the subcellular distribution of phospholipids revealed a significant increase in PIMs content of both cell wall and cell membrane of the cells grown in the presence of combination of drugs as compared to control as well as individual drugs. Mycolic acids of M. smegmatis cells were found to be main targets as combination of drugs resulted in significant decrease in total cellular as well as cell wall mycolic acids as compared to control and individual drugs. Changed lipid composition of M. smegmatis cells grown in the presence of MIC50 of EMB, SPX and combination resulted in significant surface changes as was evident from decreased limiting fluorescence (Fmax) intensity of 1-anilinonaphthalene-8-sulfonate (ANS). Thus, the results of this study suggested that ethambutol and sparfloxacin in combination exerted their antimycobacterial effect principally due to their action on phosphatidylinositolmannosides (PIMs) and mycolic acids, which form the permeability barrier of mycobacteria.     

Air Pollution: Involvement of Oxygen Radicals (A Mini Review)

In the past decades air pollution has increased worldwide. We also gained more insight into the complex interactions between different air pollutants in the atmosphere as well as their effects on living cells and organisms. It also has been unequivocally shown by several groups in different countries that oxy radicals play an outstanding role in the interconversion of air pollutants as well as during the manifestation of toxic effects. Not only living systems are affected by air pollutants, but also inorganic systems such as buildings and sculptures. In the following overview the most important reactions occuring in the atmosphere as well as effects of oxidative gaseous compounds and particles such as diesel soot and asbestos will be discussed.     

Familial true hermaphroditism: paternal and maternal transmission of true hermaphroditism (46,XX) and XX maleness in the absence of Y-chromosomal sequences

We report on 46,XX true hermaphroditism and 46,XX maleness coexisting in the same pedigree, with maternal as well as paternal transmission of the disorder. Molecular genetic analysis showed that both hermaphrodites as well as the 46,XX male were negative for Y-chromosomal sequences. Thus, this pedigree is highly informative and allows the following conclusions: first, the maternal as well as paternal transmission of the disorder allows the possibility of an autosomal dominant as well as an X-chromosomal dominant mode of inheritance; second, testicular determination in the absence of Y-specific sequences in familial 46,XX true hermaphrodites as well as in 46,XX males seems to be due to the varying expression of the same genetic defect; and third, there is incomplete penetrance of the defect.     

Hedgehog signalling: how to get from Smo to Ci and Gli

The secreted morphogens of the Hedgehog family have important roles in normal development as well as in associated pathologies, including cancer. The Hedgehog signalling pathway has been studied in Drosophila and is thought to be conserved in vertebrates. Hedgehog elicits a signalling response that activates Smoothened (Smo). There is evidence of differences between Drosophila and vertebrates concerning signalling downstream of Smo, as well as in Smo itself. Here, we discuss this evidence and its importance for investigations of the pathway and related biology, as well as for the development of drugs targeting components of the pathway for treatment of associated pathologies.     

SLX4: multitasking to maintain genome stability

The SLX4/FANCP tumor suppressor has emerged as a key player in the maintenance of genome stability, making pivotal contributions to the repair of interstrand cross-links, homologous recombination, and in response to replication stress genome-wide as well as at specific loci such as common fragile sites and telomeres. SLX4 does so in part by acting as a scaffold that controls and coordinates the XPF–ERCC1, MUS81–EME1, and SLX1 structure-specific endonucleases in different DNA repair and recombination mechanisms. It also interacts with other important DNA repair and cell cycle control factors including MSH2, PLK1, TRF2, and TOPBP1 as well as with ubiquitin and SUMO. This review aims at providing an up-to-date and comprehensive view on the key functions that SLX4 fulfills to maintain genome stability as well as to highlight and discuss areas of uncertainty and emerging concepts.     

Biotechnological uses of cyanobacteria

Cyanobacteria (blue-green algae) are 0₂-evolving photosynthesizing prokaryotes that have an extensive history of use as a human food source and as a fertilizer in rice fields. They have also been recognized as an excellent source of vitamins and proteins and as such are found in health food stores in North America and elsewhere. Cyanobacteria have a great deal of potential as a source of fine chemicals, as a biofertilizer and as a source of renewable fuel. This potential is being realized as data from research in the areas of the physiology and chemistry of these organisms are gathered and as the knowledge of cyanobacterial genetics and genetic engineering increases. We review, here, the present (and possible future) uses of cyanobacteria and assess the state of the art with respect to the genetic manipulation of cyanobacteria.     

Abundance of RNase4 and RNase5 mRNA and protein in host defence related tissues and secretions in cattle

Members of the RNaseA family are present in various tissues and secretions but their function is not well understood. Some of the RNases are proposed to participate in host defence. RNase4 and RNase5 are present in cows' milk and have antimicrobial activity. However, their presence in many tissues and secretions has not been characterised. We hypothesised that these two RNases are present in a range of tissues and secretions where they could contribute to host defence. We therefore, determined the relative abundance of RNase4 and RNase5 mRNA as well as protein levels in a range of host defence related and other tissues as well as a range of secretions in cattle, using real time PCR and western blotting. The two RNases were found to be expressed in liver, lung, pancreas, mammary gland, placenta, endometrium, small intestine, seminal vesicle, salivary gland, kidney, spleen, lymph node, skin as well as testes. Corresponding proteins were also detected in many of the above tissues, as well as in seminal fluid, mammary secretions and saliva. This study provides evidence for the presence of RNase4 and RNase5 in a range of tissues and secretions, as well as some major organs in cattle. The data are consistent with the idea that these proteins could contribute to host defence in these locations. This work contributes to growing body of data suggesting that these proteins contribute to the physiology of the organism in a more complex way than acting merely as digestive enzymes.     

Possible roles of glycosphingolipids in lipid rafts

Recent studies have suggested that glycosphingolipid (GSL)-cholesterol microdomains in cell membranes may function as platforms for the attachment of lipid-modified proteins, such as glycosylphosphatidylinositol (GPI)-anchored proteins and src-family tyrosine kinases. The microdomains are proposed to be involved in membrane trafficking of GPI-anchored proteins and in signal transduction via src-family kinases. Here, the possible roles of GSLs in the physical properties of these microdomains, as well as in membrane trafficking and signal transduction, are discussed. Sphingolipid depletion inhibits the intracellular transport of GPI-anchored proteins in biosynthetic traffic and endocytosis via GPI-anchored proteins. Antibodies against GSLs as well as GPI-anchored proteins co-precipitate src-family kinases. Antibody-mediated cross-linking of GSLs, as well as that of GPI-anchored proteins, induces a transient increase in the tyrosine phosphorylation of several substrates. Thus, GSLs have important roles in lipid rafts.     

Sphingolipid players in the leukemia arena

Sphingolipids function as bioactive mediators of different cellular processes, mostly proliferation, survival, differentiation and apoptosis, besides being structural components of cellular membranes. Involvement of sphingolipid metabolism in cancerogenesis was demonstrated in solid tumors as well as in hematological malignancies. Herein, we describe the main biological and clinical aspects of leukemias and summarize data regarding sphingolipids as mediators of apoptosis triggered in response to anti-leukemic agents and synthetic analogs as inducers of cell death as well. We also report the contribution of molecules that modulate sphingolipid metabolism to development of encouraging strategies for leukemia treatment. Finally we address how deregulation of sphingolipid metabolism is associated to occurrence of therapy resistance both in vitro and in vivo. Sphingolipids can be considered promising therapeutic tools alone or in combination with other compounds, as well as valid targets in the attempt to eradicate leukemia and overcome drug resistance.     

三门湾海域冬夏季口足目和十足目虾类的种类组成、时空分布及多样性分析

根据2007年12月和2008年6月三门湾海域的2个航次的渔业资源调查资料,研究三门湾海域口足目与十足目中虾类在冬季和夏季的密度、优势种及多样性的时空分布,并结合该调查海区的地形地貌和水文等因素对虾类的分布进行分析.结果表明,三门湾海域虾类以广温、广盐种为主,其夏季种类数高于冬季,且夏季虾类质量和尾数密度均值亦高于冬季...     

Polyphenol Oxidase Activity and Phenolic Content Pattern During Shoot Development of Grape (Vitis vinifera L.) in Different Growing Seasons

The PPO activity and content of phenolic compounds were estimated during the different growing seasons and developmental age of shoots in seven grape genotypes. Both, the total phenol content and catecholase activity were found significantly affected by the growing season, developmental age of shoot and the genotype. But, season as well as age of shoot could not influence cresolase activity. Spring as season; 30 days of sprouting as age; Gold and Anab-e-Shahi as genotypes were found better in comparison to summer as season and 15 days of sprouting as age in respect to level of phenols and PPO activity.     

CDR1as regulated by hnRNPM maintains stemness of periodontal ligament stem cells via miR-7/KLF4

CDR1as is a well-identified circular RNA with regulatory roles in a variety of physiological processes. However, the effects of CDR1as on stemness of periodontal ligament stem cells (PDLSCs) and the underlying mechanisms remain unclear. In this study, we detect CDR1as in human PDLSCs, and subsequently demonstrate that CDR1as maintains PDLSC stemness. Knockdown of CDR1as decreases the expression levels of stemness-related genes and impairs the cell's multi-differentiation and cell migration abilities, while overexpression of CDR1as increases the expression levels of stemness-related genes and enhances these abilities. Furthermore, our results indicate that the RNA-binding protein hnRNPM directly interacts with CDR1as and regulates its expression in PDLSCs. In addition, we show that CDR1as promotes the expression of stemness-related genes in PDLSCs by inhibiting miR-7-mediated suppression of KLF4 expression. Collectively, our results demonstrate that CDR1as participates in the molecular circuitry that regulates PDLSC stemness.     

Finding the intracellular signaling pathways affected by mood disorder treatments

Postmortem and brain imaging studies have revealed structural changes and cell loss in cortico-limbic regions of the brain in bipolar disorder and major depression. Consistent with these findings, mood stabilizers such as lithium ion and valproic acid, which are used to treat bipolar disorder, as well as antidepressants and electroconvulsive therapy have recently been shown to activate interconnected intracellular signaling pathways that promote neurogenesis and synaptic plasticity. These insights should assist in understanding the pathophysiology of severe mood disorders as well as aid in the development of more effective treatments.     

Synthesis of 4-cyanophenyl and 4-nitrophenyl 1,5-dithio-D-ribopyranosides as well as their 2-deoxy and 2,3-dideoxy derivatives possessing antithrombotic activity

1,2,3,4-Tetra-O-acetyl-5-thio-D-ribopyranose as well as its 1-bromide were used as donors in the reaction with 4-cyano- and 4-nitrobenzenethiol, to give the corresponding thioglycosides in different anomeric ratios depending on the reaction conditions. Zemplén deacetylation afforded 4-cyanophenyl as well as 4-nitrophenyl 1,5-dithio-alpha- and beta-D-ribopyranosides, respectively. 1,3,4-Tri-O-acetyl-2-deoxy-5-thio-D-erythro-pentopyranose was synthesized from methyl 2-deoxy-D-erythro-pentofuranoside and was coupled with 4-cyano- and 4-nitrobenzenethiol to give anomeric mixtures from which 4-cyanophenyl as well as 4-nitrophenyl 1,5-dithio-beta-D-erythro-pentopyranosides were isolated after deacetylation. 1,4-Di-O-acetyl-2,3-dideoxy-5-thio-D-glycero-pentopyranose was obtained starting from 1,2,5,6-di-O-isopropylidene-D-mannitol and used as the donor in the glycosylation reaction with 4-cyano- and 4-nitrobenzenethiol. The resulting anomeric mixtures were separated to give, after deacetylation, 4-cyanophenyl as well as 4-nitrophenyl 2,3-dideoxy-1,5-dithio-beta-D-glycero-pentopyranosides. All of these thioglycosides showed significant antithrombotic activity on rats after oral administration.     

Factors associated with birth rate and live birth rate in multi-male breeding groups of rhesus monkeys

Reproductive records of 284 female rhesus monkeys housed in six multimale corrals at the California Primate Research Center were examined for the birth seasons 1977–1982 to determine possible associations between the probability of birth or live birth and female age, parity, origin, parturition in the previous season, infant birth date, and infant birth date in previous season. Multiple logistic regression analysis was used to identify and quantitate the effects of factors on the probability of birth or live birth, while controlling for the possibly confounding effects of other factors in the model. Females who had infants early in the previous season were 2.5 times as likely to give birth as those who had infants late in the previous season. Females with two or three previous births were 2.1 times as likely to give birth, and those with four or five previous births were 6.7 times as likely to give birth as were females with no or one previous birth. Controlling for other factors (age, parity, and timing of birth in the previous season), corralborn females were 3.3 times as likely to give birth as either wild-caught or domestic-born monkeys not native to the corrals. Domestic-born females who were not corral natives were 0.3 times as likely to have live births as wild-caught females. Births late in the season were 1.8 times as likely to result in live infants as births early in the season.