The AP-2 complex interacts with γ-TuRC and regulates the proliferative capacity of neural progenitors

Centrosomes are organelles that nucleate microtubules via the activity of gamma-tubulin ring complexes (γ-TuRC). In the developing brain, centrosome integrity is central to the progression of the neural progenitor cell cycle, and its loss leads to microcephaly. We show that NPCs maintain centrosome integrity via the endocytic adaptor protein complex-2 (AP-2). NPCs lacking AP-2 exhibit defects in centrosome formation and mitotic progression, accompanied by DNA damage and accumulation of p53. This function of AP-2 in regulating the proliferative capacity of NPCs is independent of its role in clathrin-mediated endocytosis and is coupled to its association with the GCP2, GCP3, and GCP4 components of γ-TuRC. We find that AP-2 maintains γ-TuRC organization and regulates centrosome function at the level of MT nucleation. Taken together, our data reveal a novel, noncanonical function of AP-2 in regulating the proliferative capacity of NPCs and open new avenues for the identification of novel therapeutic strategies for the treatment of neurodevelopmental and neurodegenerative disorders with AP-2 complex dysfunction.

The clinical and molecular spectrum of the KDM6B-related neurodevelopmental disorder

De novo variants are a leading cause of neurodevelopmental disorders (NDDs), but because every monogenic NDD is different and usually extremely rare, it remains a major challenge to understand the complete phenotype and genotype spectrum of any morbid gene. According to OMIM, heterozygous variants in KDM6B cause "neurodevelopmental disorder with coarse facies and mild distal skeletal abnormalities." Here, by examining the molecular and clinical spectrum of 85 reported individuals with mostly de novo (likely) pathogenic KDM6B variants, we demonstrate that this description is inaccurate and potentially misleading. Cognitive deficits are seen consistently in all individuals, but the overall phenotype is highly variable. Notably, coarse facies and distal skeletal anomalies, as defined by OMIM, are rare in this expanded cohort while other features are unexpectedly common (e.g., hypotonia, psychosis, etc.). Using 3D protein structure analysis and an innovative dual Drosophila gain-of-function assay, we demonstrated a disruptive effect of 11 missense/in-frame indels located in or near the enzymatic JmJC or Zn-containing domain of KDM6B. Consistent with the role of KDM6B in human cognition, we demonstrated a role for the Drosophila KDM6B ortholog in memory and behavior. Taken together, we accurately define the broad clinical spectrum of the KDM6B-related NDD, introduce an innovative functional testing paradigm for the assessment of KDM6B variants, and demonstrate a conserved role for KDM6B in cognition and behavior. Our study demonstrates the critical importance of international collaboration, sharing of clinical data, and rigorous functional analysis of genetic variants to ensure correct disease diagnosis for rare disorders.

Improvements in Walking Distance during Nusinersen Treatment - A Prospective 3-year SMArtCARE Registry Study

BACKGROUND AND OBJECTIVES

Disease progression in patients with spinal muscular atrophy (SMA) has changed dramatically within the past years due to the approval of three different disease-modifying treatments. Nusinersen was the first drug to be approved for the treatment of SMA patients. Clinical trials provided data from infants with SMA type 1 and children with SMA type 2, but there is still insufficient evidence and only scarcely reported long-term experience for nusinersen treatment in ambulant patients. Here, we report data from the SMArtCARE registry of ambulant patients under nusinersen treatment with a follow-up period of up to 38 months.

METHODS

SMArtCARE is a disease-specific registry in Germany, Austria and Switzerland. Data are collected as real-world data during routine patient visits. Our analysis included all patients under treatment with nusinersen able to walk independently before start of treatment with focus on changes in motor function.

RESULTS

Data from 231 ambulant patients were included in the analysis. During the observation period, 31 pediatric walkers (27.2%) and 31 adult walkers (26.5%) experienced a clinically meaningful improvement of≥30 m in the 6-Minute-Walk-Test. In contrast, only five adult walkers (7.7%) showed a decline in walking distance≥30 m, and two pediatric walkers (1.8%) lost the ability to walk unassisted under treatment with nusinersen. HFMSE and RULM scores improved in pediatric and remained stable in adult patients.

CONCLUSION

Our data demonstrate a positive effect of nusinersen treatment in most ambulant pediatric and adult SMA patients. We not only observed a stabilization of disease progression or lack of deterioration, but clinically meaningful improvements in walking distance.

Improved upper limb function in non-ambulant children with SMA type 2 and 3 during nusinersen treatment: a prospective 3-years SMArtCARE registry study

Background

The development and approval of disease modifying treatments have dramatically changed disease progression in patients with spinal muscular atrophy (SMA). Nusinersen was approved in Europe in 2017 for the treatment of SMA patients irrespective of age and disease severity. Most data on therapeutic efficacy are available for the infantile-onset SMA. For patients with SMA type 2 and type 3, there is still a lack of sufficient evidence and long-term experience for nusinersen treatment. Here, we report data from the SMArtCARE registry of non-ambulant children with SMA type 2 and typen 3 under nusinersen treatment with a follow-up period of up to 38 months.

Methods

SMArtCARE is a disease-specific registry with data on patients with SMA irrespective of age, treatment regime or disease severity. Data are collected during routine patient visits as real-world outcome data. This analysis included all non-ambulant patients with SMA type 2 or 3 below 18 years of age before initiation of treatment. Primary outcomes were changes in motor function evaluated with the Hammersmith Functional Motor Scale Expanded (HFMSE) and the Revised Upper Limb Module (RULM).

Results

Data from 256 non-ambulant, pediatric patients with SMA were included in the data analysis. Improvements in motor function were more prominent in upper limb: 32.4% of patients experienced clinically meaningful improvements in RULM and 24.6% in HFMSE. 8.6% of patients gained a new motor milestone, whereas no motor milestones were lost. Only 4.3% of patients showed a clinically meaningful worsening in HFMSE and 1.2% in RULM score.

Conclusion

Our results demonstrate clinically meaningful improvements or stabilization of disease progression in non-ambulant, pediatric patients with SMA under nusinersen treatment. Changes were most evident in upper limb function and were observed continuously over the follow-up period. Our data confirm clinical trial data, while providing longer follow-up, an increased number of treated patients, and a wider range of age and disease severity.

Overexpression of METAL TOLERANCE PROTEIN8 reveals new aspects of metal transport in Arabidopsis thaliana seeds

METAL TOLERANCE PROTEIN8 (MTP8) of Arabidopsis thaliana is a member of the CATION DIFFUSION FACILITATOR (CDF) family of proteins that transports primarily manganese (Mn), but also iron (Fe). MTP8 mediates Mn allocation to specific cell types in the developing embryo, and Fe re-allocation as well as Mn tolerance during imbibition. We analysed if an overexpression of MTP8 driven by the CaMV 35S promoter has an effect on Mn tolerance during imbibition and on Mn and Fe storage in seeds, which would render it a biofortification target. Fe, Mn and Zn concentrations in MTP8-overexpressing lines in wild type and vit1-1 backgrounds were analysed by ICP-MS. Distribution of metals in intact seeds was determined by synchrotron µXRF tomography. MTP8 overexpression led to a strongly increased Mn tolerance of seeds during imbibition, supporting its effectiveness in loading excess Mn into the vacuole. In mature seeds, MTP8 overexpression did not cause a consistent increase in Mn and Fe accumulation, and it did not change the allocation pattern of these metals. Zn concentrations were consistently increased in bulk samples. The results demonstrate that Mn and Fe allocation is not determined primarily by the MTP8 expression pattern, suggesting either a cell type-specific provision of metals for vacuolar sequestration by upstream transport processes, or the determination of MTP8 activity by post-translational regulation.

Biallelic variants in HPDL cause pure and complicated hereditary spastic paraplegia

Human 4-hydroxyphenylpyruvate dioxygenase-like (HPDL) is a putative iron-containing non-heme oxygenase of unknown specificity and biological significance. We report 25 families containing 34 individuals with neurological disease associated with biallelic HPDL variants. Phenotypes ranged from juvenile-onset pure hereditary spastic paraplegia to infantile-onset spasticity and global developmental delays, sometimes complicated by episodes of neurological and respiratory decompensation. Variants included bona fide pathogenic truncating changes, although most were missense substitutions. Functionality of variants could not be determined directly as the enzymatic specificity of HPDL is unknown; however, when HPDL missense substitutions were introduced into 4-hydroxyphenylpyruvate dioxygenase (HPPD, an HPDL orthologue), they impaired the ability of HPPD to convert 4-hydroxyphenylpyruvate into homogentisate. Moreover, three additional sets of experiments provided evidence for a role of HPDL in the nervous system and further supported its link to neurological disease: (i) HPDL was expressed in the nervous system and expression increased during neural differentiation; (ii) knockdown of zebrafish hpdl led to abnormal motor behaviour, replicating aspects of the human disease; and (iii) HPDL localized to mitochondria, consistent with mitochondrial disease that is often associated with neurological manifestations. Our findings suggest that biallelic HPDL variants cause a syndrome varying from juvenile-onset pure hereditary spastic paraplegia to infantile-onset spastic tetraplegia associated with global developmental delays.

Normative Observational Nerve Ultrasound Values in School-Age Children and Adolescents and Their Application to Hereditary Neuropathies

Backgrounds: We have aimed to establish nerve ultrasound reference data in 8 to 17-year-old children and adolescents and to compare those data to younger children, adults, and age-matched children with polyneuropathies.

Methods: High-resolution ultrasounds of the nerves were performed in 117 healthy children and adolescents at 20 predefined landmarks in the neck and the extremities of both sides. Mean values, side-to-side differences and intraneural ratios, as well as upper limits have been calculated. In a second step, a comparison between 25 children and adolescents of the same age range with proven hereditary and acquired neuropathies and lysosomal storage diseases has been carried out.

Results: Nerve growth correlates significantly with age and reaches adult values at the age of around 15 years. The influence of body mass index and gender is negligible at most segments. By the use of age-specific upper limits, nerve enlargement could be seen in distinct types of neuropathies, particularly in demyelinating hereditary and inflammatory types, which is comparable to findings in adults, but also in rare lysosomal storage diseases.

Conclusion: Nerve size correlates with age during childhood and reaches a climax in younger adults. Age-matched reference data are inevitable to differ between hypertrophic and non-hypertrophic nerve damage, e.g., in neuropathies.

The time window for successful right-hemispheric language reorganization in children

AIM

To identify, in a retrospective, observational study, the time window during which successful right-hemispheric language reorganization is possible after left-hemispheric brain damage.

METHOD

25 patients (10 females; age 6-41 years; ≥12 months after insult; age at insult 0;3-15;11 years) with acute, language-relevant left-hemispheric insults acquired during childhood and adolescence completed questionnaires for self-assessment of language problems. 12 patients of those reporting no (n = 8) or only moderate (n = 4) language problems participated in language fMRI.

RESULTS

Language outcome of lesions occurring before 5 years of age (n = 7) was always favorable, and language was right-lateralized (2 patients: age at lesion < 2 years) or bilateral (3 patients: age at lesion 2-5 years). Following lesions occurring after 5 years of age, language outcome was often unfavorable (11/18 patients: moderate or severe problems), and of the 7 patients without problems, none showed right-hemispheric reorganization (fMRI available in 4).

INTERPRETATION

The combination of normal language outcome and right-hemispheric language reorganization after a left-hemispheric lesion sustained after the neonatal period is extremely rare. Functionally sufficient right-hemispheric language was documented in only two patients with lesions acquired before two years of age.

Predicting hand function after hemidisconnection

Hemidisconnections (i.e. hemispherectomies or hemispherotomies) invariably lead to contralateral hemiparesis. Many patients with a pre-existing hemiparesis, however, experience no deterioration in motor functions, and some can still grasp with their paretic hand after hemidisconnection. The scope of our study was to predict this phenomenon. Hypothesizing that preserved contralateral grasping ability after hemidisconnection can only occur in patients controlling their paretic hands via ipsilateral corticospinal projections already in the preoperative situation, we analysed the asymmetries of the brainstem (by manual magnetic resonance imaging volumetry) and of the structural connectivity of the corticospinal tracts within the brainstem (by magnetic resonance imaging diffusion tractography), assuming that marked hypoplasia or Wallerian degeneration on the lesioned side in patients who can grasp with their paretic hands indicate ipsilateral control. One hundred and two patients who underwent hemidisconnections between 0.8 and 36 years of age were included. Before the operation, contralateral hand function was normal in 3/102 patients, 47/102 patients showed hemiparetic grasping ability and 52/102 patients could not grasp with their paretic hands. After hemidisconnection, 20/102 patients showed a preserved grasping ability, and 5/102 patients began to grasp with their paretic hands only after the operation. All these 25 patients suffered from pre- or perinatal brain lesions. Thirty of 102 patients lost their grasping ability. This group included all seven patients with a post-neonatally acquired or progressive brain lesion who could grasp before the operation, and also all three patients with a preoperatively normal hand function. The remaining 52/102 patients were unable to grasp pre- and postoperatively. On magnetic resonance imaging, the patients with preserved grasping showed significantly more asymmetric brainstem volumes than the patients who lost their grasping ability. Similarly, these patients showed striking asymmetries in the structural connectivity of the corticospinal tracts. In summary, normal preoperative hand function and a post-neonatally acquired or progressive lesion predict a loss of grasping ability after hemidisconnection. A postoperatively preserved grasping ability is possible in hemiparetic patients with pre- or perinatal lesions, and this is highly likely when the brainstem is asymmetric and especially when the structural connectivity of the corticospinal tracts within the brainstem is asymmetric.

Comparison of different tractography algorithms and validation by intraoperative stimulation in a child with a brain tumor

BACKGROUND

Advanced modalities such as functional magnetic resonance imaging (MRI) and diffusion MR tractography offer in vivo information about brain networks and are therefore increasingly used for neurosurgical planning in children also.

AIM

This study aims to study the application of routine and advanced tractography algorithms and its comparison with intraoperative subcortical electrical stimulation.

METHOD

Presurgical functional MRI and MR diffusion tractography were performed on a 6-year-old patient presenting with seizures, but no motor symptoms, due to a neuroectodermal tumor in the left central region. Three different tractography algorithms were compared: deterministic diffusion tensor imaging (DTI)-tracking, probabilistic DTI-tracking, and probabilistic constrained spherical deconvolution tracking (pCSD).

RESULTS

All three tractography algorithms could localize the core of the corticospinal tract with good agreement. The pCSD-tracking algorithm was more sensitive in revealing the anatomically most realistic fiber distribution and a proportion of fibers traversing a solid part of the tumor. Intraoperative stimulation confirmed these fibers close to the tumor. As a result, only a subtotal resection was performed, preventing postoperative sensorimotor deficits.

CONCLUSION

Although, all tractography algorithms successfully identified the core of the corticospinal pathway, deterministic DTI-tractography, as widely used in clinical neuronavigation software, only insufficiently visualized critical fibers here. We believe these results argue for a stronger consideration of advanced tractography approaches in neurosurgical planning.

The photosynthesis of individual algal cells during the cell cycle of Scenedesmus quadricauda studied by chlorophyll fluorescence kinetic microscopy

A microscope for imaging of chlorophyll fluorescence kinetics was equipped with a chamber that allows the growth of an immobilised population of algae and their study under well-defined conditions. Single cells of the chlorococcal alga Scenedesmus quadricauda were grown and recorded for periods of whole cell cycles (up to 48 h) displaying a normal course of cell development. Heterogeneity in fluorescence yield among individual coenobia in the population and among different cells in one coenobium were analysed. Differences were observed both in the shape of Kautsky transients and in the modulation of fluorescence parameter values during the progress of the cell cycle. The extent of heterogeneity in fluorescence parameters was cell cycle dependent - in some phases of the cycle, the population was almost homogeneous, while distinct heterogeneity was observed, in particular between the protoplast division and the release of the daughter coenobia. The heterogeneity was not random but reflected developmental processes.

Cellular compartmentation of nickel in the hyperaccumulators Alyssum lesbiacum, Alyssum bertolonii and Thlaspi goesingense

Nickel uptake and cellular compartmentation were investigated in three Ni hyperaccumulators: Alyssum bertolonii (Desv), Alyssum lesbiacum (Candargy) and Thlaspi goesingense (Hálácsy). The three species showed similar hyperaccumulation of Ni, but T. goesingense was less tolerant to Ni than the two Alyssum species. An addition of 500 mg Ni kg(-1) to a nutrient-rich growth medium significantly increased shoot biomass of all three species, suggesting that the Ni hyperaccumulators have a higher requirement for Ni than normal plants. Energy-dispersive X-ray microanalysis (EDXA) was performed on frozen-hydrated tissues of leaves (all species) and stems (Alyssum only). In all species analysed, Ni was distributed preferentially in the epidermal cells, most likely in the vacuoles, of the leaves and stems. In stems, there was a second peak of Ni in the boundary cells between the cortical parenchyma and the vascular cylinder. The non-glandular trichomes on the leaf surfaces of the two Alyssum species were highly enriched with Ca, but contained little Ni except in the base. In the leaves of T. goesingense, the large elongated epidermal cells contained more Ni than the cells of the stomatal complexes. The role of cellular compartmentation in Ni hyperaccumulation is discussed.

Segregation of nitrogen fixation and oxygenic photosynthesis in the marine cyanobacterium Trichodesmium

In the modern ocean, a significant amount of nitrogen fixation is attributed to filamentous, nonheterocystous cyanobacteria of the genus Trichodesmium. In these organisms, nitrogen fixation is confined to the photoperiod and occurs simultaneously with oxygenic photosynthesis. Nitrogenase, the enzyme responsible for biological N2 fixation, is irreversibly inhibited by oxygen in vitro. How nitrogenase is protected from damage by photosynthetically produced O2 was once an enigma. Using fast repetition rate fluorometry and fluorescence kinetic microscopy, we show that there is both temporal and spatial segregation of N2 fixation and photosynthesis within the photoperiod. Linear photosynthetic electron transport protects nitrogenase by reducing photosynthetically evolved O2 in photosystem I (PSI). We postulate that in the early evolutionary phase of oxygenic photosynthesis, nitrogenase served as an electron acceptor for anaerobic heterotrophic metabolism and that PSI was favored by selection because it provided a micro-anaerobic environment for N2 fixation in cyanobacteria.

Cellular compartmentation of cadmium and zinc in relation to other elements in the hyperaccumulator Arabidopsis halleri

The cellular compartmentation of elements was analysed in the Zn hyperaccumulator Arabidopsis halleri (L.) O'Kane & Al-Shehbaz (=Cardaminopsis halleri) using energy-dispersive X-ray microanalysis of frozen-hydrated tissues. Quantitative data were obtained using oxygen as an internal standard in the analyses of vacuoles, whereas a peak/background ratio method was used for quantification of elements in pollen and dehydrated trichomes. Arabidopsis halleri was found to hyperaccumulate not only Zn but also Cd in the shoot biomass. While large concentrations of Zn and Cd were found in the leaves and roots, flowers contained very little. In roots grown hydroponically, Zn and Cd accumulated in the cell wall of the rhizodermis (root epidermis), mainly due to precipitation of Zn/Cd phosphates. In leaves, the trichomes had by far the largest concentrations of Zn and Cd. Inside the trichomes there was a striking sub-cellular compartmentation, with almost all the Zn and Cd being accumulated in a narrow ring in the trichome base. This distribution pattern was very different from that for Ca and P. The epidermal cells other than trichomes were very small and contained lower concentrations of Zn and Cd than mesophyll cells. In particular, the concentrations of Cd and Zn in the mesophyll cells increased markedly in response to increasing Zn and Cd concentrations in the nutrient solution. This indicates that the mesophyll cells in the leaves of A. halleri are the major storage site for Zn and Cd, and play an important role in their hyperaccumulation.

Photometric method for the quantification of chlorophylls and their derivatives in complex mixtures: fitting with Gauss-peak spectra

Accurate quantification of pigments in mixtures is essential in all cases in which separation of pigments by chromatography is impracticable for one reason or another. An example is the analysis of in vivo formation of heavy metal-substituted chlorophylls in heavy metal-stressed plants. We describe here a novel, accurate UV/VIS spectrophotometric method for the quantification of individual chlorophyll derivatives in complex mixtures, which has the potential for universal applicability for mixtures difficult to separate. The method is based on the description of each pigment spectrum by a series of Gaussian peaks. A sample spectrum is then fitted by a linear combination of these "Gauss-peak spectra" including an automatic correction of wavelength inaccuracy and baseline instability of the spectrometer as well as a correction of the widening of absorbance peaks in more concentrated pigment solutions. The automatic correction of peak shifts can also partially correct shifts caused by processes like allomerization. In this paper, we present the Gauss-peak spectra for Mg-chlorophyll a, b, c, pheophytin a, b, c, Cu-chlorophyll a, b, c, and Zn-chlorophyll a in acetone; Mg-chlorophyll a, b, pheophytin a, b, Cu-chlorophyll a, b, allomerized Cu-chlorophyll a, b, and Zn-chlorophyll a, b in cyclohexane; Mg-chlorophyll a, b, pheophytin a, b, and Cu-chlorophyll a, b in diethyl ether.

[Studies on the bond strength of various titanium-ceramic base materials]

The present contribution presents the results of a study comparing the bond strength of Ohara Titan Bond (Tanaka, Bad Homburg), Vita Titankeramik (Vita, Bad Säckingen) and Duceratin Experimental Titankeramik (Ducera, Rosbach) fused to titanium with that of Vita VMK 68 fused to Wiron 88. For the measurement of the bond strength we utilized the three point bending test of fracture mechanics.

[Prophylaxis programs in the dental office--evaluation of a survey of dentists]

Questionnaires on dental prophylaxis were sent to one thousand West German dentists. 457 of them were returned. 61.7% of the dentists interviewed were working in urban, 38.8% in rural areas. The results revealed that the importance of dental prophylaxis is still underestimated today.

[New construction principles for Silicoater-cast maxillary prosthesis]

A problem often seen in the dentist's practice is the relining of a removable Cr-Co-prosthesis in the reduced maxillary arch. For this reason we have developed a prosthesis that has its base completely surrounded with acrylic. This modification is nearly as stable as a total Cr-Co-prothesis. The results on 15 patients restored with this new prosthesis were very positive.

[Comparative studies on different full and veneer-ceramic crowns]

Under quasi-clinical conditions, Dicor, Hi-Ceram, Ceraplatin and PFM (porcelain butt margin) crowns with ceramic shoulders manufactured by commercial laboratories for the same metal master die were examined for marginal defects under the electron microscope. With equal cementing conditions and points of measurement for all crowns, the PFM crowns were found to be significantly superior to the other crown types. However, this result becomes relativistic in view of the great statistical variances involved.

[Temporary acrylic crowns and bridges--particular considerations of the periodontium]

Dentists generally fail to recognize the importance of the correct construction and finishing of acrylic temporary restorations from the periodontologic point of view. The potential traumatic effect of these restorations on the gingiva is rarely considered. A survey of 1000 dentists in Western Germany revealed some common errors. The results are compared with the clinical requirements for temporary restorations.

[Studies on marginal fit of Dicor crowns]

Dicor crowns may present marginal defects, among other reasons because they require preparation of a circular ledge with rounded internal line angles. In studying this problem, 21 teeth that could no longer be saved were prepared in vivo and provided with Dicor crowns in our hospital. After remaining in place for 3 months these teeth were extracted. Subsequently their marginal areas were studied by SEM and histological preparations were made and measured. The marginal defects of Dicor crowns revealed slightly less favorable values than the Hi-Ceram crowns investigated one year ago, but these values are still within the range of clinical acceptability.

[Hi-Ceram and marginal gingiva: a clinical study]

The past few years have seen great efforts in prosthodontics to find a way of replacing the metal portion necessary in the construction of ceramic veneer crowns by nonmetallic anorganic materials. As a result, various novel procedures for the production of fully mineral crowns have been developed. Among these, the Hi-Ceram system has attained particular attention. In a clinical study the reactions of the marginal gingiva to Hi-Ceram have been compared to those to ceramometallic crowns.

[Modes of anchorage of partial dentures using Silicoater adhesive attachments of titanium and Wiron 88]

The results of the study presented suggest that the use of Silicoater adhesive attachments allows medium-term, minimum-invasive, esthetically satisfactory and inexpensive prosthetic rehabilitation of caries-free partially edentulous dentitions without the application of anesthesia. Despite its favorable mechanical properties, however, the high nickle content of Wiron 88, as it has been in use up to now, must be considered as a drawback, because it may produce allergic reactions in patients. Due to the positive properties of titanium, particularly its biocompatibility and its corrosion resistance, this material has been tested clinically in comparison to Wiron 88.

[Dentist-patient communication under time constraints]

In the present clinical trial dentists were asked to talk to patients about the subject of "Prevention". A patient-dentist conversation was to be conducted in two different time frames. In the first group the dentist took as much time as seemed necessary for communicating with the patient. In the second group the restricting condition was that approximately an average number of patients had appointments under office conditions. The results demonstrate that under controlled conditions dentists show a communicative behavior which will focus the patients attention on compliant oral hygiene. However, under the pressure of limited time, this behavior will no longer be sufficient to achieve optimum patient compliance through such a talk alone.

Nucleotide sequence of the VP1 gene of the foot-and-mouth disease virus strain A Venceslau

The VP1 coat protein of FMDV strain A Venceslau (Aven) consists of 213 amino acid residues. Serum neutralization tests demonstrated that strain Aven is closely related to strain A Argentina/79 (A79) but significantly different from strain A24Cruzeiro (A24). There is a strong correlation between the amino acid sequences and the serological data. Nucleotide and amino acid sequence analyses of VP1 showed that serologically related viruses (Aven and A79) differ less in this region of the genome than those of serologically distinct viruses (Aven vs. A24). The most significant variation between Aven and A24 occurs at amino acid positions 43 to 46, in which all four residues are different.

Biotechnological approach to a new foot-and-mouth disease virus vaccine

Major contributions towards the development of an absolutely safe FMDV vaccine are evident. With the identification of VP1 as the immunogenic protein, it is possible to manufacture a subunit vaccine via biotechnology. DNA sequences encoding the VP1 protein can be introduced into a bacterium with ease; under the appropriate conditions, large amounts of VP1 can be produced in a short time. The accumulation of amino acid sequences generated by recombinant DNA techniques allows identification of antigenic domains, which are the basis of variability among serotype and subtype viruses. As a result, vaccine production by chemical synthesis of short peptides corresponding to the antigenic determinants is greatly facilitated. At present, results from experimental vaccines employing genetically engineered or chemically synthesized VP1 antigens against homologous virus infection are encouraging. The current approach of preparing vaccine is to utilize the antigenic specificity of the virus. Since FMDV undergoes antigenic drift, variants not neutralized by type-specific serum will arise. An alternative approach is to prepare vaccines based on antigenic sites shared among all serotype and subtype viruses.

Comparison of the major antigenic determinants of different serotypes of foot-and-mouth disease virus

Complete nucleotide sequences which code for the capsid protein VP1 of two foot-and-mouth disease virus serotypes, O1Campos/Brazil/58 and C3Indaial/Brazil/71, have been determined. Ten available VP1 sequences (three serotype O, three serotype C, and four serotype A) were aligned and compared. Our evidence suggests that O1BFS/Britain/68 and O1K/Germany/66 are closely related to O1Campos/Brazil/58. Significant variations were observed between the nucleotide sequences of C3Indaial determined by two different laboratories. These differences are probably the result of virus adaptation and propagation in different laboratories. In one of the isolates (C3Biogen), a 13-base-pair stem and 13-base-pair loop structure is located in the 134-158 amino acid variable region. Isolates of different serotypes differ at two highly variable regions, amino acid positions 42-60 and 134-158, but isolates of the same serotype show major differences only in the variable region between amino acids 134 and 158. Since the remaining amino acid sequence of VP1 is highly conserved, we conclude that the 134-158 amino acid variable region is involved in subtype specificity, whereas both variable regions contribute to serotype differences.

Vitellogenin in Drosophila melanogaster: sequence of the yolk protein I gene and its flanking regions

We have isolated recombinant DNA clones coding for female specific proteins from Drosophila melanogaster. By screening with 32P-(A)+RNA from male and female flies, respectively, we were able to isolate a set of 100 cDNA clones which showed a positive hybridization signal for RNA from female flies. These clones have been rescreened with RNA isolated from fat body of two day old male and female flies. We obtained four positive cDNA clones. Isolation of the corresponding genomic sequences, construction of the physical map and comparing it with the restriction maps published by Barnett et al. (1) led us to conclude that we had isolated the genes coding for two of the three known yolk protein precursors (vitellogenins), YP I and YP II. The sequence of the YP I gene was determined. It gives rise to a protein of 48 700 dalton MW which might be cleaved to a MW of 46 700 during transport. The coding sequence is interrupted by a single intron of 75 bases in length. The proposed leader sequence starts at a region homologous to six heat shock gene sequences at the site of initiation of transcription, suggesting the existence of an 11 bp cap specific consensus sequence for Drosophila melanogaster.

Nucleotide sequence and corresponding amino acid sequence of the gene for the major antigen of foot and mouth disease virus

A segment of 1160 nucleotides of the FMDV genome has been sequenced using three overlapping fragments of cloned cDNA from FMDV strain O1K. This sequence contains the coding sequence for the viral capsid protein VP1 as shown by its homology to known and newly determined amino acid sequences from this man antigenic polypeptide of the FMDV virion. The structural gene for VP1 comprises 639 nucleotides which specify a sequence of 213 amino acids for the VP1 protein. The coding sequence is not flanked by start and stop codons which is consistent with the mode of biosynthesis of VP1 by post-translational processing of a polyprotein precursor.