Recombination in human mitochondrial DNA?

The possibility of recombination in human mitochondrial DNA (mtDNA) has been hotly debated over the last few years. In this study, a general model of recombination in circular molecules is developed and applied to a recently published African sample (n = 21) of complete mtDNA sequences. It is shown that the power of correlation measures to detect recombination in circular molecules can be vanishingly small and that the data are consistent with the given model and no recombination only if the overall heterogeneity in mutation rate is <0.09.     

More plastids in human parasites?

Trypanosomatid parasites are disease agents with an extraordinarily broad host range including humans, livestock and plants. Recent work has revealed that trypanosomatids harbour numerous genes sharing apparent common ancestry with plants and/or bacteria. Although there is no evidence of a plastid (chloroplast-like organelle) in trypanosomatids, the presence of such genes suggests lateral gene transfer from some photosynthetic organism(s) during trypanosomatid evolution. Remarkably, many products of these horizontally acquired genes now function in the glycosome, a highly modified peroxisome unique to trypanosomatids and their near relatives.     

N-Acetyl-β-glucosaminidases in human spleen

1. The N-acetyl-beta-glucosaminidase of human spleen has been separated by gel electrophoresis into two components, an acidic form A and a basic form B. 2. The two forms are readily separated on DEAE-cellulose and have been concentrated 50-fold and sevenfold respectively. 3. They show similar K(m) values towards 4-methylumbelliferyl N-acetyl-beta-d-glucosaminide, and have the same pH optima when compared in citrate, phosphate or acetate buffers. They are inhibited to a similar extent by acetate, heparin, N-acetylgalactosaminolactone, N-acetyl-beta-d-galactosamine and N-acetyl-beta-d-glucosamine. Specificity for C-4 orientation is not absolute and p-nitrophenyl beta-galactosaminide is also hydrolysed but at a rate only 11.6% of that for the corresponding glucosaminide. 4. N-Acetyl-beta-glucosaminidase B is stable over a wider pH range than is N-acetyl-beta-glucosaminidase A, and is less easily denatured by heat. 5. Tissue fractionation indicates that both the A and B forms are present in the lysosomal fraction, whereas the supernatant contains the A form only. 6. Evidence is presented to indicate that the A form contains a number of sialic acid residues.     

HLA class Ⅱ alleles in human sporotrichosis in Mexican Amerindians

Human leukocyte antigen (HLA) class Ⅱ alleles are involved in antigen processing and presentation to T lymphocytes during fungal infections. However, few studies have investigated HLA genes in fungal diseases, or in sporotrichosis infections. Here, the frequencies of HLA-DRβ1 in 50 healthy volunteers and 9 patients with sporotrichosis from an endemic area in Mexico were determined to define their role in genetic susceptibility to this infection. Also, the frequencies of HLA-DRβ1 haplotypes were compared with a historic control group of healthy Mexican individuals. The patients presented that DR4 and DR8 increased, which were more than twice the control''s values, whereas local controls (endemic area) presented DR*04:01 increased, compared with the control group from Mexico City. The data suggest that involvement of HLA antigens could affect the outcomes of the host-fungi interaction in sporotrichosis by regulating the immune response to Sporothrix schenckii complex.     

HLA class Ⅱ alleles in human sporotrichosis in Mexican Amerindians

poor OS. HMP19 plays a role in metastasis/tumor suppression and offers a prognostic value for EOC. HMP19, as a new inhibitor, strongly inhibits metastasis and partially attenuates tumor growth in EOC.     

Host�Cpathogen coevolution in human tuberculosis

Tuberculosis (TB) is a disease of antiquity. Yet TB today still causes more adult deaths than any other single infectious disease. Recent studies show that contrary to the common view postulating an animal origin for TB, Mycobacterium tuberculosis complex (MTBC), the causative agent of TB, emerged as a human pathogen in Africa and colonized the world accompanying the Out-of-Africa migrations of modern humans. More recently, evolutionarily ‘modern’ lineages of MTBC expanded as a consequence of the global human population increase, and spread throughout the world following waves of exploration, trade and conquest. While epidemiological data suggest that the different phylogenetic lineages of MTBC might have adapted to different human populations, overall, the phylogenetically ‘modern’ MTBC lineages are more successful in terms of their geographical spread compared with the ‘ancient’ lineages. Interestingly, the global success of ‘modern’ MTBC correlates with a hypo-inflammatory phenotype in macrophages, possibly reflecting higher virulence, and a shorter latency in humans. Finally, various human genetic variants have been associated with different MTBC lineages, suggesting an interaction between human genetic diversity and MTBC variation. In summary, the biology and the epidemiology of human TB have been shaped by the long-standing association between MTBC and its human host.     

Meta-operation conflict resolution for human–human interaction in collaborative feature-based CAD systems

Conflicts resolution is one of the key issues in maintaining consistency and in supporting smooth human–human interaction for real-time collaborative systems. This paper presents a novel approach of meta-operation conflict resolution for feature-based collaborative CAD system. Although commutative replicated data type (CRDT) is an emerging technique for conflict resolution, it is not capable of resolving conflicts among meta operations for 3D CAD systems. By defining 3 types of meta operations, this work extends CRDT capability to meta operation conflict resolution from 1D to 3D applications. The paper defines the dependency, casuality, conflict and compatible relations specific for 3D collaborative CAD systems. The conflicts of feature-based operations are automatically detected by tracking topological entity changes with the assistance of a persistent data structure, topological entity structure tree (\(TES\_Tree\)). An efficient commutativity-based confliction combination method is proposed to preserve the design intention of each user in a transparent way and maintains the eventual consistent state of the system. The proposed methods are tested in a prototype system with case studies, time complexity analysis and correctness proof.     

Autoradiographic study on the localization of estradiol-17β in neonatal mouse uterus and cervix

Summary The uptake of ³H-estradiol-17 in the neonatal mouse uterus and cervix has been studied by an autoradiographic method. When the radio-active hormone is administered in vivo and in vitro, grains are found to be concentrated above the nuclei both in the uterine and cervical epithelium and stroma. Grain counts revealed that the nuclear concentration of grains is higher at 4 h than at 2 h after isotope injection. The cervical epithelium has a higher nuclear concentration than the uterine epithelium both in vivo and in vitro. In the stroma, this situation is reversed except after in vitro treatment of the tissues.In the cervix, more of the hormone seems to be located within the nucleus while in the uterus a higher proportion of the grains are found in the vicinity of the nuclear periphery.Although the nuclear concentration of grains is higher at 4 h than at 2 h, the number of grains above the sections is lower at 4 h. Both in vivo and in vitro, the number of grains is higher above the stromal than above the epithelial compartments of the uterus and cervix.Five days old animals showed the same labeling pattern. The differences in uptake and distribution of ³H-estradiol are discussed in relation to other known differences in the hormone responsiveness in these tissues.We are greatly indebted to Professor W.E. Stumpf and the Laboratories for Reproductive Biology, University of North Carolina Medical School for the opportunity to study the method of dry mount autoradiography. The work has been supported by the Norwegian Research Council for Science and the Humanities and by the Norwegian Cancer Society (Landsforeningen mot Kreft)     

Expression of human β-defensin-2 gene induced by CpG-DNA in human B cells

Defensins have a broad range of antimicrobial activity against bacteria, fungi, and viruses. The expression of human β-defensin-2 (hBD-2) is prevalently observed in epithelial cells and is induced by bacterial infection. Here, we have shown that the expression of the hBD-2 gene and release of hBD-2 protein into the medium is up-regulated in response to CpG-DNA in human B cell line RPMI 8226. The induction of hBD-2 was dependent on CG sequence and phosphorothioate backbone-modification. This was also confirmed in primary human lymphocytes. To shed light on the molecular mechanism involved in hBD-2 induction by CpG-DNA, we examined the contribution of the NF-κB signaling pathway in RPMI 8226 cells. Suppression of MyD88 function and inhibition of NF-κB nuclear localization blocked hBD-2 induction. The NF-κB pathway inhibitors also abolished hBD-2 induction. These results may contribute to a better understanding on the therapeutic effects of CpG-DNA against infectious diseases.     

Polymorphisms in the human DNA polymerase β gene

Recently, evidence has accumulated that mutations in DNA repair genes might be associated with certain steps in carcinogenesis. The DNA polymerase gene is one of the DNA repair genes, and mutations in it have been detected in 83% of human colorectal cancers. To assess the involvement of polymerase gene mutations in the development of human prostate cancers, we performed sequence analyses of human DNA samples. Unexpectedly, we found six regions that were polymorphic. This information should be taken into consideration at the time of sequence analysis of the DNA polymerase gene.s     

Transport of poly-β-hydroxybutyrate in human plasma

Poly-β-hydroxybutyrate (PHB) is an amphiphilic lipid that has been found to be a ubiquitous component of the cellular membranes of bacteria, plants and animals. The distribution of PHB in human plasma was investigated using chemical and immunological methods. PHB concentrations proved highly variable; in a random group of 24 blood donors, total plasma PHB ranged from 0.60 to 18.2 mg/l, with a mean of 3.5 mg/l. In plasma separated by density gradient ultracentrifugation, lipoproteins carried 20–30% of total plasma PHB; 6–14% in the very low density lipoproteins (VLDL), 8–16% in the low density lipoproteins (LDL), and < 3% in the high density lipoproteins (HDL). The majority of plasma PHB (70–80%) was found in protein fractions of density > 1.22 g/ml. Western blot analysis of the high density fractions with anti-PHB F(ab')₂ identified albumin as the major PHB-binding protein. The affinity of albumin for PHB was confirmed by in vitro studies which demonstrated transfer of ¹⁴C-PHB from chloroform into aqueous solutions of human and bovine serum albumins. PHB was less tightly bound to LDL than to other plasma components; the polymer could be isolated from LDL by extraction with chloroform, or by digestion with alkaline hypochlorite, but it could not similarly be recovered from VLDL or albumin. PHB in the LDL correlated positively with total plasma cholesterol and LDL cholesterol, and negatively with HDL cholesterol. The wide concentration range of PHB in plasma, its presence in VLDL and LDL and absence in HDL, coupled with its physical properties, suggest it may have important physiological effects.     

Studies of α-protein in human cell cultures

Summary α-Protein growth fraction (AGF) eliminates the 60- to 90-day adaptive phase required to establish actively growing cultures of HeLa (Gey), human heart (Girardi), KB (Eagle) and other established cell lines in serum-free chemically defined medium A₃. AGF is effective at less than 0.4 μg per ml. By using the procedures described in the text, it is possiblee to culture HeLa cells is very simple media such as Eagle's basal medium. The properties of AGF are such that it may be adsorbed on glass or plastic flasks. Glass flasks treated with AGF retain full activity after washing with acetone, and treatment with ethyl ether and chemically defined medium. Adsorbed AGF is destroyed by trypsin. AGF can detoxify protamines, polylysines or histones. It will reverse the aggregation response induced by adding complexes composed of carboxymethylcellulose (CMC) and basic proteins. The results support the contention that highly adsorptive AGF functions at the cell surface and is capable of modifying the response of the cell to its environment.     

Changes in human γ-globulin preparations during storage

Во время хранения, человека γ-глобулин препараты протеолиза проходить медленно, в результате в составе двух фракций сплит. Один из них (γx) медленнее, чем обычно γ-глобулин, в то время как другие (γи) больше быстрыми темпами. Темпы разрушения в плазме подготовка охватывает несколько лет, тогда как в препаратов, полученных в результате haemolysed и плацентарной материала это несколько месяцев. Аналогичная разбивка была искусственно вызванной в плазмин, trypsin и papain. Определенный артикль изменения могут быть обнаружены путем immunoelectrophoresis, но электрофореза в Агар и высокоскоростного центрифугирования также дают приблизительную картину состояния подготовки. Определенный артикль γx дроби могут быть восстановлены в immunoelectrophoretically чистом состоянии путем осадков с сульфата аммония (более 50% насыщения), или с Zn₂₊ солей (в supernatant жидкости составляет более 50 мм концентрация). Определенный артикль γ_и фракция crystallizes из решений с низкой ионной силы в виде минуту, игла-как, оптически неактивных кристаллов. Причины изменений в соответствующую препаратов и биохимических и Иммунохимические аспекты с учетом явления рассматриваются.