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PubMed1978

[Cardiomyopathy in Duchenne muscular dystrophy. Part 2: serum enzymes, vector-cardiography, and echo-cardiography in 143 patients (author's transl)].

To diagnose a possible latent or manifested cardiomyopathy, 143 male patients between 2 and 21 years of age with confirmed Duchenne muscular dystrophy were examined for serum enzymes, by electrocardiography, vector-cardiography, and echo-cardiography. The results contain information on 1. the quantitative cellular myocardial degeneration process, 2. the disturbed cellular depolarization and nerve-conduction processes in the area of the right and left ventricular myocard, and 3. the disturbed left ventricular function which, in the initial state, is only documented by a discrete decrease of contractility caused by a manifested decreased ejection output. The pathological contraction and relaxation process of the heart muscle cell and its dependency on calcium ion transport as pathogenic background is discussed.

Adolescent↗

PubMed2020

Battling Neurodegenerative Diseases with Adeno-Associated Virus-Based Approaches.

Neurodegenerative diseases (NDDs) are most commonly found in adults and remain essentially incurable. Gene therapy using AAV vectors is a rapidly-growing field of experimental medicine that holds promise for the treatment of NDDs. To date, the delivery of a therapeutic gene into target cells via AAV represents a major obstacle in the field. Ideally, transgenes should be delivered into the target cells specifically and efficiently, while promiscuous or off-target gene delivery should be minimized to avoid toxicity. In the pursuit of an ideal vehicle for NDD gene therapy, a broad variety of vector systems have been explored. Here we specifically outline the advantages of adeno-associated virus (AAV)-based vector systems for NDD therapy application. In contrast to many reviews on NDDs that can be found in the literature, this review is rather focused on AAV vector selection and their preclinical testing in experimental and preclinical NDD models. Preclinical and in vitro data reveal the strong potential of AAV for NDD-related diagnostics and therapeutic strategies.

Animals↗

PubMed2026

Distribution of transgene in the rodent choroid plexus after intracerebroventricular injection of adeno-associated virus.

Using adeno-associated virus to transfer genetic information to the choroid plexus has emerged as a promising route for long-term gene therapy in the brain for a variety of conditions. Overexpression of proteins has proved effective in small animal models but few attempts have been made to translate this technology to clinic, suppress the activity of a protein of interest, or further expand the limited capsid serotypes known to have choroid plexus tropism. We utilise transfer of green fluorescent protein to show choroid plexus epithelium tropism for novel AAV6 derived capsid ShH10Y445F in mouse, rat and porcine tissue explant cultures. In vivo tropism is shown in the mouse following stereotactic intracerebroventricular injection. We examined the distribution of viral transduction across the choroid plexus in all four ventricles following a single unilateral intracerebroventricular injection using both green fluorescent protein as a transgene, but also the CRISPR/Cas9 system to deliver permanent knockdown of apical water channel aquaporin-1. Quantitative immunofluorescence and SURVEYOR assay were used to statistically assess the magnitude and extent of choroid plexus knockdown across the ventricular system. We conclude that serotype ShH10Y445F targets choroid plexus epithelium in mouse, rat and pig; and when carrying the CRISPR/Cas9 system can reduce target protein expression in these cells. Transduced choroid plexus epithelial cells distribute unevenly with a bias toward the lateral ventricle on the injected side and a preferential infection of choroid plexus in the lateral over the third and fourth ventricles. Overcoming irregular distribution represents a challenge for clinical translation of this technology where clinical efficacy may require manipulation of the entire choroid plexus.

Animals↗

PubMed1979

Identification of the C. coli dnaK (groPC756) gene product.

The E. coli dnaK (groPC756) gene product is essential for bacteriophage lambda DNA replication. Bacterial DNA segments carrying this gene have been cloned onto a bacteriophage lambda vector. The product of the dnaK gene has been identified on SDS polyacrylamide gels after infection of UV-irradiated E. coli cells. The dnaK gene codes for a polypeptide with an apparent molecular weight of 93,000-Mr. Transducing phages carrying amber mutations in the dnaK gene fail to induce the synthesis of the 93,000-Mr polypeptide chain upon infection of sup+ bacteria, but do so upon infection of supF bacteria. E coli carrying the dnaK756 mutation are, in addition, temperature sensitive for growth at 43 degrees C. It is shown that the dnaK756 mutation results in an overproduction of the dnaK gene product at that temperature.

Bacterial Proteins↗

PubMed1978

Transmission of Northway and St. Louis encephalitis viruses by arctic mosquitoes.

Transmission of a Canadian arctic isolate of Northway virus has been demonstrated after incubation of arctic Aedes communis mosquitoes at 13 degrees C for 27 days after intrathoracic injection of 300 plaque forming units of virus. Replication has also been demonstrated after intrathoracic injection of domestic A. aegypti mosquitoes of this virus. Virions of Northway virus, 84--92 nm diameter were morphologically typical of a bunyavirus after propagation in salivary glands of A. communis or in tissue cultures of baby hamster kidney (BHK-21) cells. An Ontario isolate of St. Louis encephalitis was transmitted by bites of A. communis after 27 days incubation at 13 degrees C after oral ingestion of 3 or 30 mouse LD50 virus. This mosquito species transmitted virus after 13 to 76 days incubation at 13 degrees C following intrathoracic injection of 3 mouse LD50 or higher virus doses.

Aedes↗

PubMed2025

Identification of potential biomarkers and mechanisms for keloid disorder based on comprehensive bioinformatics analysis and machine learning algorithms.

BACKGROUND: Keloid disorder (KD) encompasses a spectrum of fibroproliferative dermal conditions, the pathogenesis remains complex and incompletely understood. This study sought to identify biomarkers and potential therapeutic targets for KD through an integrative bioinformatics approach and machine learning analysis of RNA sequencing data. METHODS: RNA sequencing was performed on skin tissue samples from 13 patients with KD and 14 healthy controls. Using weighted gene co-expression network analysis and differential expression analysis revealed differentially expressed key module genes, and the CytoHubba plugin identified candidate genes. Subsequently analyzed using least absolute shrinkage and selection operator (LASSO) and support vector machine recursive feature elimination (SVM-RFE) methods to pinpoint feature genes associated with KD. Following this, biomarkers were determined through expression level validation, enrichment analysis, and immune infiltration analysis. RESULTS: A total of 420 differentially expressed key module genes were identified, and the top 10 genes with DMNC values were selected as candidate genes. Five feature genes were selected through LASSO and SVM-RFE, with NID2, MFAP2, COL8A1, and P4HA3 showing significant expression differences between KD and control samples, along with consistent expression patterns across datasets, identified as potential biomarkers. These four biomarkers were proved to possess high diagnostic potential, and they were found to exhibit significant positive correlations with one another. Functional enrichment analysis indicated that the primary KEGG pathways associated with these biomarkers included "steroid hormone biosynthesis" and "cytokine-cytokine receptor interaction." Moreover, immune infiltration analysis revealed that the four biomarkers were negatively correlated with type 17 T helper cells and positively correlated with 15 immune cell types, including activated B cells and central memory CD4 T cells. CONCLUSION: In conclusion, NID2, MFAP2, COL8A1, and P4HA3 were identified as key biomarkers for KD, offering new avenues for more targeted and effective diagnostic and therapeutic strategies for managing this condition.

Humans↗

PubMed2025

Influence of genetic factors of humans, mosquitoes and parasites, on the evolution of Plasmodium falciparum infections, malaria transmission and genetic control methods: a review of the literature.

Despite significant progress, malaria remains a public health problem in many regions, particularly in sub-Saharan Africa. This situation is partly explained by the mosquito's resistance to insecticides and the emergence of parasite resistance to antimalarial drugs. Indeed, in spite of the various vectors' controls, insecticide resistance emerges from multi-generational selection and poses worldwide concern. In parallel, artemisinin resistance unfortunately emerged independently in multiple countries in eastern Africa. Since 2014, artemisinin resistance has been observed in 6 countries in Africa and, more concerningly, the evidence from longitudinal molecular surveys in these countries suggests that it is spreading. While phenotypic evidence of treatment failure is still limited, the increasing reports of validated artemisinin resistance mutations are alarming. Unlike the emergence of artemisinin resistance in South-East Asia, our understanding of the genetic determinants of artemisinin resistance and our ability to sequence and map the spread of resistance are significantly greater. In addition to mosquito and parasite genetics affecting malaria evolution, many human individual variants have been identified that are associated with malaria protection, but the most important of all relates to the structure or function of red blood cells, the classical polymorphisms that causes sickle cell trait, α-thalassaemia, G6PD deficiency, and the major red cell blood group variants. In that biological complex context, there is a need to characterize the various genetic factors in Plasmodium falciparum, humans and mosquitoes that are potentially associated with resistance to antimalarial drugs and insecticides, and their involvement in the evolution, severity and transmission of malaria. In this direction, A comprehensive literature review was conducted to capture the objectives highlighted above. The advances in genomic surveillance and emerging genetic control strategies, such as gene drive technology were also considered in this review. We used search engines such as PubMed and Google scholar to retrieve articles useful to the objective of this paper and information on the knowledge of genetic factors and methods that contributed to malaria control were synthesized.

Humans↗

PubMed1979

Recent advances in applied malaria immunology.

Our present knowledge of cellular and humoral factors which are involved in immunity to plasmodial infections are discussed. Immunization against plasmodial infection has been achieved in birds, rodents, simians, and humans. Avian hosts have been immunized against gametocytes which resulted in inhibition of gametocytes within the mosquito vector. Immunization of humans against plasmodial gametocytes would indirectly protect them against malaria by blocking mosquito transmission to other susceptible individuals. Immunization by sporozoites provides short-lived protection against sporozoite challenge, but gives no protection against erythrocytic forms. Some success has been obtained in immunizing avian and mammalian hosts with exoerythrocytic forms obtained from cultured avian cells. The most significant advances have occurred in immunizing simian hosts against simian or human malaria by vaccinating with fresh erythrocytic merozoites or a nonviable lyophilized antigen obtained from intraerythrocytic forms. The development of an antigen preparation suitable for use as a human malaria vaccine is dependent upon prior development of an in vitro system which would provide adequate amounts of parasite material. Efforts to cultivate the sporogonic, exoerythrocytic, and erythrocytic, and erythrocytic phases of plasmodia as well as the feasibility of using these forms for vaccination are discussed.

Animals↗

PubMed1977

Mechanistic state vector model for cell killing by ionizing radiation.

By use of the mechanistic state vector model (MSV model) it is demonstrated that under circumstances where cell division during irradiation is unlikely: 1. A cell survival curve (dose-log surviving fraction curve) that is exponential can be obtained even though some of the surviving cells may have nonlethal damage. Exponential survival curves are said to have zero curvature. 2. In some cases, in the absence of a mixed population, the slope of a single-dose survival curve may decrease in magnitude, as the dose increases for a range of doses. These curves are said to show negative curvature for that range of doses. Fractionating the dose or decreasing the dose rate may result in enhanced cell killing. 3. The initial slope of a mammalian cell survival curve should be independent of the dose rate and number of dose fractions provided that the number of cells having lethal damage builds up to a steady level during the post irradiation time regime. The magnitude of the initial slope will depend on properties of the cells and on properties of the radiation. 4. A nonzero initial slope in the cell survival curve, after exposure to low linear energy transfer (LET) radiation, may be due to biology, rather than physics.

Animals↗

PubMed1979

Cloning of immunoglobulin kappa light chain genes from mouse liver and myeloma MOPC 173.

The organization of the kappa chain constant region gene was compared in DNA from an immunoglobulin-producing mouse myeloma (MOPC 173) and from liver. In situ hybridization using the Southern blotting technique revealed constant region gene-containing EcoRI-DNA fragments of 14 and 20 kb in the myeloma tissue whereas one EcoRI-DNA fragment with a length of 15 kb was found in liver DNA. After enrichment by RPC-5 chromatography and preparative electrophoresis the 14 kb fragment from MOPC 173 DNA and the 15 kb fragment from liver DNA were cloned in the bacteriophage lambda vector Charon 4A using in vitro packaging. Extensive characterization of the two fragments by restriction endonuclease mapping, in situ hybridization, and electron microscopy (R-loop and heteroduplex) showed that both fragments contain the constant region but no MOPC 173 variable region gene. Both fragments are homologous over a length of 12.5 kb including the constant region but differ from one another starting about 2.7 kb from the 5' end of the constant region gene. This indicates that the 14 kb EcoRI-DNA fragment from the myeloma tissue clearly resulted from somatic DNA rearrangement although it does not seem to carry the MOPC 173 variable region gene. These observations suggest that somatic DNA rearrangement of immunoglobulin light chain genes can involve both homologous chromosomes.Images

Animals↗

PubMed1979

Plasmids with temperature-dependent copy number for amplification of cloned genes and their products.

Miniplasmids (pKN402 and pKN410) were isolated from runaway-replication mutants of plasmid R1. At 30 degrees C these miniplasmids are present in 20--50 copies per cell of Escherichia coli, whereas at temperatures above 35 degrees C the plasmids replicate without copy number control during 2--3 h. At the end of this period plasmid DNA amounts to about 75% of the total DNA. During the gene amplification, growth and protein synthesis continue at normal rate leading to a drastic amplification of plasmid gene products. Plasmids pKN402 (4.6 Md) and pKN410 (10 Md) have single restriction sites for restriction endonucleases EcoRI and HindIII; in addition plamid pKN410 has a single BamHI site and carries ampicillin resistance. The plasmids can therefore be used as cloning vectors. Several genes were cloned into these vectors using the EcoRI sites; chromosomal as well as plasmid-coded beta-lactamase was found to be amplified up to 400-fold after thermal induction of the runaway replication. Vectors of this temperature-dependent class will be useful in the production of large quantities of genes and gene products. These plasmids have lost their mobilization capacity. Runaway replication is lethal to the host bacteria in rich media. These two properties contribute to the safe use of the plasmids as cloning vehicles.

Cloning, Molecular↗

PubMed1979

Aspects of the sporogonic development of Leucocytozoon tawaki of the Fiordland crested penguin in its primary vector, Austrosimulium ungulatum: an ultrastructural study.

Early oocysts of Leucocytozoon tawaki Fallis, Bisset and Allison were located between the basal lamina and the midgut epithelium of the vector, Austrosimulium ungulatum. The spherical oocysts were surrounded by an amorphous, electron-dense wall and contained a large, central core of closely spaced dense particles, the crystalloid inclusion. Around the latter were many concentrically arranged cisternae of granular endoplasmic reticulum. A few large, poorly defined nuclei, some of which contained spindle apparatus, were seen. Sporozoite formation occurred around the peripheral cytoplasm of maturing oocysts. The sporozoite pellicle was subtended by 30 microtubules which appeared to originate from the most posterior of 3 dense, polar rings. Each forming sporozoite contained a central nucleus, mitochondrion, and a crystalloid inclusion both anterior and posterior to the nucleus. The nature and significance of the crystalloid in Leucocytozoan species and other apicomplexans is discussed with special reference to similar viruslike inclusions in the sporogonic stages of certain species of Plasmodium.

Animals↗

PubMedDate not supplied

[Construction and molecular cloning of hybrid plasmids containing specific fragments of Escherichia coli DNA].

In the paper a convenient procedure for the isolation of specific Eco RI-fragments of E. coli genome and their amplification on Km-resistance plasmid vector CKdelta11 is described. Plasmid CKdelta11 contains Col E1 replicon and has only one Eco RI site. The hybrid molecules were constructed in vitro using Eco RI-digestion followed by ligation. Then appropriated E. coli strain (polyauxotrophic strain E. coli K12 AB 2463) was transformed with ligated DNA mixture and hybrid plasmids, containing arg, leu, his and thr chromosomal markers were selected by molecular cloning and isolated from the obtained E. coli clones. The hybrid plasmids have two Eco RI sites and consist of one Eco RI-fragment of initial plasmid CKdelta11 and one Eco RI-fragment of El coli DNA. The method described allows to isolate and amplify on hybrid plasmids DNA fragments, containing any selectable genes or genes adjacent to the selectable ones.

Chemical Phenomena↗

PubMedDate not supplied

Studies on the development of Theileria annulata Dschunskowsky and Luhs, 1904 in the tick--Hyalomma anatolicum anatolicum Koch, 1844.

The endogenous development of Theileria annulata in the vector tick--Hyalomma anatolicum anatolicum has been described. Parasites within and outside the erythrocytes were seen in the gut contents of larvae and nymphs immediately after their removal from the infected cattle but not after 24 hours. Two bodies resembling the intra-erythrocytic stage of the parasite, lying close to each other were seen near the gut epithelium of a larva on the 4th day of its dropping off the infected host. Neither multiplication nor union of the parasite resulting in zygote formation in the gut of the tick, was noticed. Next stage of the parasite was seen in the salivary glands of nymphs and adults. The pre-infective stage characterized by indistinct chromatin dots (nuclei) surrounded with cytoplasm was seen in alveolar cells of the salivary glands of nymphs and adult ticks from the first to the third day of their feeding of the host. This stage progressed to the infective stage consisting of distinct chromatin particles (the infective particles) surrounded with cytoplasm in the salivary glands of nymphs and adult ticks after the second and first day, respectively of feeding on the host. The infective particles were also seen within ducts of the salivary glands.

Animals↗

PubMed1978

Cloning of restriction and modification genes in E. coli: the HbaII system from Haemophilus haemolyticus.

The genes for a Class II restriction-modification system (HhaII) from Haemophilus haemolyticus have been cloned in Escherichia coli. The vector used for cloning was plasmid pBR322 which confers resistance to tetracycline and ampicillin and contains a single endonuclease R-PstI site, (formula: see text), in the ampicillin gene. The procedure developed by Bolivar et al. (1977) was used to form DNA recombinants. H. haemolyticus DNA was cleaved with PstI endonuclease and poly(dC) extensions were added to the 3'-OH termini using terminal deoxynucleotidyl transferase. Circular pBR322 DNA was cleaved to linear molecules with PstI endonuclease and poly(dG) extensions were added to the 3'-OH termini, thus regenerating the PstI cleavage site sequences. Recombinant molecules, formed by annealing the two DNAs, were used to transfect a restriction and modification-deficient strain of E. coli (HB101 r-m-recA). Tetracycline-resistant clones were tested for acquisition of restriction phenotype (as measured by growth on plates seeded with phage lambdacI-0). A single phage-resistant clone was found. The recombinant plasmid, pD110, isolated from this clone, had acquired 3 kilobases of additional DNA which could be excised with PstI endonuclease. In addition to the restriction function, cells carrying the plasmid expressed the HhaII modification function. Both activities have been partially purified by single-stranded DNA-agarose chromatography. The cloned HhaII restriction activity yields cleavage patterns identical to HinfI. A restriction map of the cloned DNA segment is presented.

DNA Restriction Enzymes↗

PubMed2021

Adeno-associated Virus (AAV) Capsid Chimeras with Enhanced Infectivity Reveal a Core Element in the AAV Genome Critical for both Cell Transduction and Capsid Assembly.

Adeno-associated viruses (AAV) have attracted significant attention in the field of gene and cell therapy due to highly effective delivery of therapeutic genes into human cells. The ability to generate recombinant AAV vectors compromised of unique or substituted protein sequences has led to the development of capsid variants with improved therapeutic properties. Seeking novel AAV vectors capable of enhanced transduction for therapeutic applications, we have developed a series of unique capsid variants termed AAV X-Vivo (AAV-XV) derived from chimeras of AAV12 VP1/2 sequences and the VP3 sequence of AAV6. These AAV variants showed enhanced infection of human primary T cells, hematopoietic stem cells, and neuronal cell lines over wildtype parental viruses, and superiority over AAV6 for genomic integration of DNA sequences by AAV alone or in combination with CRISPR gene editing. AAV-XV variants demonstrate transduction efficiency equivalent to AAV6 at multiplicities of infection 2 logs lower, enabling T cell engineering at low AAV doses. The protein coding sequence of these novel AAV chimeras revealed disruptions within the assembly-activating protein (AAP) which likely accounted for observed lower virus yield. A series of genome alterations, reverting the AAP sequence back to wildtype AAV6, had a negative impact on the enhanced transduction seen with AAV-VX, indicating overlapping functions within this sequence for both viral assembly and effective T cell transduction. Our findings show these AAV-XV variants are highly efficient at cell transduction at low dose and demonstrates the importance of the AAP coding region in both viral particle assembly and cell infection.IMPORTANCE A major hurdle to the therapeutic potential of AAV in gene therapy lies in achieving clinically meaningful AAV doses, and secondarily, ability to manufacture commercially viable titers of AAV to support this. By virtue of neutralizing antibodies against AAV that impede patient repeat-dosing, the dose of AAV for in vivo gene delivery has been high, which has resulted in unfortunate recent safety concerns and deaths in patients given higher-dose AAV gene therapy. We have generated new AAV variants possessing unique combinations of capsid proteins for gene and cell therapy applications termed AAV-XV, which have high levels of cell transduction and gene delivery at lower MOI. Furthermore, we demonstrate a novel finding, and an important consideration for recombinant AAV design, that a region of the AAV genome encoding the capsid viral protein and AAP is critical for both virus yield and the enhancement of infection/transduction.

Journal Article↗

PubMed2026

MADCAP: isolation of novel nAb-naïve AAV capsids from metagenomic data.

UNLABELLED: Gene therapy using adeno-associated virus (AAV) vectors offers promising treatment for genetic disorders, but significant limitations restrict clinical application. Current AAV serotypes exhibit strong liver tropism and require high doses for extra-hepatic targeting, and pre-existing antibodies (NAbs) exclude up to 50% of potential patients. Evolutionarily distant isolates can evade neutralization but typically transduce human tissues poorly and require extensive engineering. We developed MADCAP (Metagenomic AAV Discovery and Capsid Annotation Pipeline) to systematically mine metagenomic data for functional, clinically relevant AAV capsids. We hypothesized that these sources might contain capsids that do not circulate widely in humans, can transduce human cells, and avoid neutralization. We screened 4.2 million metagenomic samples and identified 139 novel AAV capsid isolates which were tested for viral capsid assembly, viability, neutralization evasion, and tissue transduction in non-human primates. While natural serotypes (AAV1, AAV2, AAV9) were neutralized at low dilutions of pooled human immunoglobulin (IVIG), 68% of tested MADCAP capsids exhibited minimal to undetectable neutralization even at supra-physiological IVIG concentrations. Systemically delivered MADCAP capsids effectively transduced multiple clinically relevant tissues in non-human primates. Two capsids, MC46 and MC55, demonstrated improved CNS tropism compared to AAV9 while maintaining comparable production yields. In passive transfer studies, MC46 retained full transduction efficiency in the presence of human antibodies, while AAV9 transduction was completely lost. This work establishes metagenomic mining as a powerful tool for accelerating AAV capsid discovery, identifying isolates with favorable tissue tropisms and resistance to broadly neutralizing antibodies. IMPORTANCE: This work provides proof of concept that potentially clinically relevant AAVs can be isolated from metagenomic data. Our findings lay the groundwork for accelerated discovery of AAV capsids which could potentially increase the accessibility and effectiveness of AAV gene therapy.

AAV↗