Optical plasticity of mammalian cells

Transparency is widespread in nature, ranging from transparent insect wings to ocular tissues that enable you to read this text, and transparent marine vertebrates. And yet, cells and tissue models in biology are usually strongly light scattering and optically opaque, precluding deep optical microscopy. Here we describe the directed evolution of cultured mammalian cells toward increased transparency. We find that mutations greatly diversify the optical phenotype of Chinese Hamster Ovary cells, a cultured mammalian cell line. Furthermore, only three rounds of high-throughput optical selection and competitive growth are required to yield fit cells with greatly improved transparency. Based on 15 monoclonal cell lines derived from this directed evolution experiment, we find that the evolved transparency frequently goes along with a reduction of nuclear granularity and physiological shifts in gene expression profiles. In the future this optical plasticity of mammalian cells may facilitate genetic clearance of living tissues for in vivo microscopy.

Rod nuclear architecture determines contrast transmission of the retina and behavioral sensitivity in mice

Rod photoreceptors of nocturnal mammals display a striking inversion of nuclear architecture, which has been proposed as an evolutionary adaptation to dark environments. However, the nature of visual benefits and the underlying mechanisms remains unclear. It is widely assumed that improvements in nocturnal vision would depend on maximization of photon capture at the expense of image detail. Here, we show that retinal optical quality improves 2-fold during terminal development, and that this enhancement is caused by nuclear inversion. We further demonstrate that improved retinal contrast transmission, rather than photon-budget or resolution, enhances scotopic contrast sensitivity by 18–27%, and improves motion detection capabilities up to 10-fold in dim environments. Our findings therefore add functional significance to a prominent exception of nuclear organization and establish retinal contrast transmission as a decisive determinant of mammalian visual perception.

Ndel1-derived peptides modulate bidirectional transport of injected beads in the squid giant axon

Bidirectional transport is a key issue in cellular biology. It requires coordination between microtubule-associated molecular motors that work in opposing directions. The major retrograde and anterograde motors involved in bidirectional transport are cytoplasmic dynein and conventional kinesin, respectively. It is clear that failures in molecular motor activity bear severe consequences, especially in the nervous system. Neuronal migration may be impaired during brain development, and impaired molecular motor activity in the adult is one of the hallmarks of neurodegenerative diseases leading to neuronal cell death. The mechanisms that regulate or coordinate kinesin and dynein activity to generate bidirectional transport of the same cargo are of utmost importance. We examined how Ndel1, a cytoplasmic dynein binding protein, may regulate non-vesicular bidirectional transport. Soluble Ndel1 protein, Ndel1-derived peptides or control proteins were mixed with fluorescent beads, injected into the squid giant axon, and the bead movements were recorded using time-lapse microscopy. Automated tracking allowed for extraction and unbiased analysis of a large data set. Beads moved in both directions with a clear bias to the anterograde direction. Velocities were distributed over a broad range and were typically slower than those associated with fast vesicle transport. Ironically, the main effect of Ndel1 and its derived peptides was an enhancement of anterograde motion. We propose that they may function primarily by inhibition of dynein-dependent resistance, which suggests that both dynein and kinesin motors may remain engaged with microtubules during bidirectional transport.

The triple A syndrome is due to mutations in ALADIN, a novel member of the nuclear pore complex

The triple A syndrome (MIM#231550) is a rare autosomal recessive disorder characterized by adrenocorticotropic hormone (ACTH) resistant adrenal failure, achalasia, alacrima, and a variety of neurological and dermatological features. The triple A syndrome is caused by mutations in the AAAS gene, which encodes a protein known as ALADIN (ALacrima Achalasia aDrenal Insufficiency Neurologic disorder). ALADIN is a new WD-repeat protein that has no significant homology to any previously identified WD-repeat protein. It has been shown that it colocalizes with nuclear pore complexes (NPCs), a finding that strongly suggests an involvement of ALADIN in nucleocytoplasmic transport. An investigation of 110 families with triple A syndrome disclosed mutation hot spots including Q15K (exon 1), and S293P (exon 8), which occur in 17 and 21 families from different geographical regions, respectively. The variable phenotype of all patients cannot be correlated with the localization and the nature of the ALADIN mutations. Thus, modifying genes/factors may be involved in the progression of this neurodegenerative disease. The lack of AAAS mutations in eight patients and negative linkage to chromosome 12q13 in three families are suggestive of genetic heterogeneity. To examine the cellular localization of ALADIN mutants causing triple A syndrome, we investigated nine different ALADIN-mutants: 2 nonsense (W84X, Q456X), 2 frameshift (F157fsX171, G397fsX414) and 5 point mutations (Q15K, L25P, H160R, S263P, L381R) by transfection experiments with green fluorescence protein. Mutants were predominantly localized in the cytoplasm, but also found in the nucleus indicating that ALADIN is essential for NPC targeting. To investigate physiological functions of ALADIN in vivo, we generated and analysed Aaas-/- knockout mice by homologous recombination in embryonic stem cells. Surprisingly, required animals lack any gross abnormality in adrenal and nervous system function. Further studies have to investigate the role of ALADIN at NPCs and to identify interacting proteins. Functional analyses of ALADIN may permit further understanding of its role for adrenocortical function and neurodevelopment.

Cat scratch disease due to Bartonella henselae infection mimicking parotid malignancy

An unusual Bartonella henselae infection presenting clinically as a putative parotid cancer was diagnosed based on serological tests, histomorphology and amplification of a 16S-rDNA sequence of Bartonella henselae. The patient improved greatly upon antibiotic treatment and did not require surgery. Although uncommon, infection with Bartonella spp., particularly Bartonella henselae, should be included in the differential diagnosis of parotid tumors.

Consecutive geoelectric measurements reveal the downward movement of an oxidation zone

An investigation program for monitoring pyrite oxidation on a conveyer bridge dump used geoelectric measurement for monitoring the progress of pyrite oxidation within the dump. The results of the geoelectric measurement show that low soil-pH and high pore water conductivity correlate with low soil resistivity values. The soil resistivity values are dominated by high pore water conductivity. The influence of changes in water saturation on resistivity was comparably low. An increase in pyrite oxidation was observed in areas with high porosity due to low dump density. Consecutive geoelectric measurements revealed locally differentiated downward movement of an oxidation zone caused by dump heterogeneity.

[Psychotherapy research and child psychotherapy practice]

Psychotherapy research results are viewed under the aspect of relevance and irrelevance for psychotherapeutic practice. The difficulties to develop effective research designs for children, and adolescents are described, and possible research perspectives are developed for this complex domain. Especially the amount of variables in combination with developmental stages of children, and adolescents creates extreme difficulties to develop research designs to give an answer to the question, which therapeutic approach is better than others in the near future. Some conclusions from research results are made for psychotherapeutic practice.

Two new species of Syncephalis (Zoopagales, Piptocephalidaceae)

Two new species of Syncephalis, Syncephalis torpedospora and Syncephalis parvula, are described. They were isolated from agricultural soil in Germany and have been maintained as haustorial mycoparasites on Mortierella alpina. Syncephalis torpedospora bears one-spored merosporangia, S. parvula two-spored merosporangia on the upper hemisphere of the globose fertile vesicle. Both are relatively small members of the genus Syncephalis. Key words: Mucorales, mycoparasitism, Piptocephalidaceae, Syncephalis, Zygomycetes.

[Alcohol and the digestive tract]

Alcohol leads to acute and chronic defects at the alimentary tract. Immediate and indirect effects are often not to be deliminated easily in the individual case. In the oesophagus above all disturbances of motility, reduction of the tonus, gastroesophageal reflux, oesophagotitides, Barrett's syndrome and carcinoma of the oesophagus develop. The Mallory-Weiss- and the Boerhaavesyndrome are to be regarded more as indirect associated sequelae. As to the stomach haemorrhagic gastrotitides and haemorrhages from erosions of the mucous membrane, as to the intestine changes of the motility, diarrhoea and malabsorptions.

[Laparoscopy in diseases of the extrahepatic bile ducts]

Nearly regularly the laparoscopy gives the possibility of a free vision to the gall-bladder and a reliable judgment of pathologic changes. Indications are above all clarification of the causes of cholestase, negative cholangiogram, relapsing, particularly bland chronic cholecystitis. Apart from its diagnositsc evidence the laparoscopy is able to give references to the further therapeutic approach. Laparoscopy is further indicated in suspicion of a malignant tumour. The direct and transhepatic puncture of the gall-bladder for the radiological description of the biliary ducts was no more dealt with; ERC and PTC are to be preferred to these methods.

[Laparoscopy in chronic gallbladder diseases]

The laparoscopy is the only riskless possibility of directly inspecting the gall-bladder, to ascertain the diagnosis of a chronic cholecystitis, further to consider the indications to internal or surgical measures. For the judgment the form of the gall-bladder, the behaviour of its wall with different colouring, oedema and furthermore its behaviour to neighbouring organs are of decisive evidence. In a disease of the bile-ducts the laparoscopy allows to prove or to exclude a participation of the liver. For the judgment of the activity of a disease of the gall-bladder should, however, always be used clinical and radiological findings, the microbiological investigation of the A-, B-, and C-bile and the testing of the reflex of the gall-bladder. This is necessary with regard to the therapy.

[Dysphagia, diagnostic and therapeutic measures]

Dysphagia is a symptom of organically or functionally conditioned diseases of the oesophagus. In all circumstances it demands an immediate clarification of the etiology considering appropriate therapeutical measures and above all may be first reference to the carcinoma of the oesophagus.

[Comparison of the value of ERCP, angiography and scintigraphy in pancreatic diseases]

The endoscopic retrograde cholangiopancreaticography, angiography and scintigraphy have a different value in the diagnostics of chronic pancreatitis and carcinoma of the pancreas. The scintigraphy of pancreas has the lowest value. It should not alone be the basis for making the diagnosis or planning the treatment. In chronic pancreatitis the endoscopic retrograde cholangiopancreaticography has precedence of angiography. The chronic pancreatitis may angiographically be recognised only in the late phase. However, the angiography can give valuable references to the planning of the operation. At a suspicion of the pancreas malignoma the endoscopic retrograde cholangiopancreaticography and the angiography have nearly the same value in the plan of diagnostics and they both should be performed.

[The effect of carbenoxolone on stress ulcers in rats]

By an immobilisation with a 72 hour's interruption of intake of fluid and nutrition stress ulcers were produced in the stomach of Wistar rats. Through a sound 34 animals received daily 25 mg/kg/body weight carbenoxolon. In them ulcers were found in nearly the same number as in the 30 controls. A conspicuous accumulation of ulcers in the pre-stomach or glandular stomach was not observed. A protective effect of the carbenoxolon could not be proved.

[Diagnostic value of bulboscopy]

Bulboscopy is a proved routine examination in radiological suspicion of changes in the duodenum, in duodenal ulcers, haemorrhages from the superior gastrointestinal tract, also as emergency endoscopy, and in unclear epigastric complaints. The endoscopy of the duodenal bulb is better than the radiological examination, especially when a cicatricial bulb is present. Flat ulcers often cannot be proved by radiological examination. Nevertheless the radiological examination should always be carried out, as also endoscopically in the cicatricial bulb ulcers may be overseen. Endoscopically the florid duodenal ulcer can be differentiated in several groups. Some a prognostic importance is ascribed.

[Chronic liver diseases with negative laboratory findings]

Chronic liver diseases may be overlooked, when regular laboratory-chemical findings are overvalued. This is important especially for those which coincide with a particupation of the bile ducts. Even in insignificant clinical references laparoscopy and biopsy under direct vision are necessary. The blind biopsy of the liver is not always sufficient as it does not regularly deliver characteristic tissue.