Analysis of triquetral-lunate fusion

Fusion of the centers of the triquetral and lunate (the os lunato-triquetrum) was observed in 1.6% of 7,543 subjects primarily of African origin as compared with 0.1% of 11,663 persons of European origin. The fusion was twice as common in females as in males, multifactorial inheritance was suggested in the lineages studied, and a possible selective disadvantage was postulated after comparison with West African fusion frequencies.     

In vitro study of newborn rat brain maturation: implication for sudden infant death syndrome.

We have used slice preparation from newborn rats to study the development of the nucleus tractus solitarius neuronal network and brain intracellular phosphorus metabolites. As shown previously on adults, the newborn preparation retains local excitatory and inhibitory synaptic connections and enables study of intrinsic electrical properties in the nucleus tractus solitarius. Electrophysiological investigation of inhibitory synaptic transmission demonstrated a maturational step at days 4-6 after birth. Nuclear magnetic resonance spectroscopy of brain slices revealed a metabolic maturation between postnatal days 11 and 17. Results emphasize the differential maturation steps during the postnatal development of rat central nervous system. Possibly, Sudden Infant Death Syndrome may result from the abnormal timing in the occurrence of these steps.     

Molecular basis of intercellular adhesion in the biofilm-forming Staphylococcus epidermidis

The Staphylococcus epidermidis genes icaABC are involved in the synthesis of the polysaccharide intercellular adhesin (PIA), which is located mainly on the cell surface, as shown by immunofluorescence studies with PIA-specific antiserum. PIA was shown to be a linear β-1,6-linked glucosaminoglycan composed of at least 130 2-deoxy-2-amino-D-glucopyrano-syl residues of which 80–85% are N-acetylated, the rest being non-N-acetylated and positively charged. A transposon insertion in the icaABC gene cluster (ica, intercellular adhesion) led to the loss of several traits, such as the ability to form a biofilm on a polystyrene surface, cell aggregation, and PIA production. The mutant could be complemented by transformation with the IcaABC-carrying plasmid pCN27. Transfer of pCN27 into the heterologous host Staphylococcus carnosus led to the formation of large cell aggregates, the formation of a biofilm on a glass surface, and PIA expression. The nucleotide sequence of icaABC suggests that the three genes are organized in an operon and that they are co-transcribed from the mapped ica A promoter. Ica A contains four potential transmembrane helices, indicative of a membrane location. The deduced Ica A sequence shows similarity to those of polysaccharide-polymerizing enzymes, the most pronounced being with a Rhizobium meliloti N-acetylglucosaminyltransferase involved in lipo-chitin biosynthesis (22.5% overall identity and 37.4% overall similarity). This similarity suggests that Ica A has N-acetylglucosaminyltransferase activity in the formation     

HeteroTOCSY-based experiments for measuring heteronuclear relaxation in nucleic acids and proteins

Summary While both ³¹P and ¹¹³Cd are present at locations of interest in many different macromolecular systems, heteronuclear-detected relaxation measurements on these nuclei have been restrained by limitations in either resolution or signal-to-noise ratio. We have developed hetero TOCSY-based methods to overcome both of these problems. Two-dimensional versions of these experiments were utilized to measure ³¹P T₁ and T₂ values in DNA oligonucleotides; the additional resolution offered by a second dimension allowed determination of these values for most of the ³¹P resonances in a DNA dodecamer. The results from the experiments indicated that there was little significant variation in T₁ values for the different phosphates in the DNA dodecamer; however, the T₂ values showed a clear pattern, with lower values in the interior of the sequence than at the ends of the helix. Furthermore, a significant correlation between ³¹P chemical shifts and T₂ values was observed. One-dimensional, frequency-selective versions of these experiments were also developed for use on systems containing a smaller number of heteronuclear spins. These methods were applied to investigate the heteronuclear relaxation properties of ¹¹³Cd in ¹¹³Cd₂LAC9(61), a Cys₆Zn₂ DNA-binding domain. Data from the experiments confirm biochemical evidence that more significant differences occur in the metal-protein interactions between the two metal-binding sites than has been previously identified for proteins containing this motif.     

Calcium buffering in presynaptic nerve terminals. I. Evidence for involvement of a nonmitochondrial ATP-dependent sequestration mechanism

A latent ATP-dependent Ca storage system is enriched in preparations of pinched-off presynaptic nerve terminals (synaptosomes), and is exposed when the terminals are disrupted by osmotic shock or saponin treatment. The data indicate that a fraction of the Ca uptake (measured with 45Ca) is associated with the intraterminal mitochondria; it is blocked by ruthenium red, by FCCP, and by azide + dinitrophenol + oligomycin. There is, however, a residual ATP-dependent Ca uptake that is insensitive to the aforementioned poisons; this (nonmitochondrial) Ca uptake is blocked by tetracaine, mersalyl and A-23187. Moreover, A-23187 rapidly releases previously accumulated Ca from these (nonmitochondrial) storage sites, whereas the Ca chelator, EGTA, does not. The proteolytic enzyme, trypsin, spares the mitochondria but inactivates the nonmitochondrial Ca uptake mechanism. Chemical measurements of total Ca indicate that the ATP-dependent Ca uptake at the nonmitochondrial sites involves the net transfer of Ca from medium to tissue fragments. This system can sequester Ca when the ambient-ionized Ca2+ concentration (buffered with EGTA) is less than 0.3 micrometer; brain mitochondria take up little Ca when the ionized Ca2+ level is this low. Preliminary subfractionation studies indicate that the nonmitochondrial Ca storage system does not sediment with synaptic vesicles. We propose that this Ca storage system, which has many properties comparable to those of skeletal muscle sarcoplasmic reticulum, may be associated with intraterminal smooth endoplasmic reticulum. This Ca-sequestering organelle may help to buffer intracellular Ca.     

MR弥散加权成像对鉴别诊断良恶性椎体压缩性骨折的临床价值研究

目的：探讨MR弥散加权成像（DWI）鉴别诊断良恶性椎体压缩性骨折的临床价值。方法：对57例经临床或病理证实的椎体良恶性压缩性骨折患者行矢状位T1M、T2WI、T2WI／FS及DWI扫描,研究其在常规序列和DWI序列上的表现,将常规MR序列和DWI序列检出率进行比较,测量正常椎体及病变椎体的表观弥散系数（ADC）值,并进行统计学分析。结果：（1）MR常规序列和DWI序列（b=500s／mm2）表现：良性椎体压缩性骨折呈长T1长或等T2改变,T2WI／FS呈高信号,DWI可以呈高信号、等信号及低信号;恶性椎体压缩性骨折呈长T1长T2信号,大部分病灶T2WUFS及DWI呈高信号,少数变现为低信号;（2）MR常规序列和DWI序列（b=500s／mm2）病灶检出率的比较：T1WI、T2WI／FS及DWI序列病灶检出率均高于T2WI序列,其间的差别有显著性意义（P〈0．01）,T1WI、T2WI／FS及DWI序列病灶检出率之间无显著性差异（P〉0．01）;（3）ADC值比较：在DWI（b=500s／mm2）上,良性组ADC值为（2．03±0．83）×10^3mm^2/s,恶性组ADC值为（1．37±0．75）×10^-3mm^2/s,正常组ADC值为（0．36±0．21）×10^-3mm^2／s,成像条件相同时,良性组高于恶性组,两组间有明显的统计学意义（P〈0．05）。结论：DWI可较好的反映椎体的弥散特征,ADC值作为量化指标可对良恶性椎体压缩性骨折进行可靠鉴别。     

The use of common elder Sambucus nigra to promote Aphidophagous syrphids in apple orchards

Elder shrubs (Sambucus nigra L.) were planted in an experimental apple orchard as bordering hedgerow with the objective of rearing syrphids (Diptera: Syrphidae) and consequently enhancing the biological control of the rosy apple aphid Dysaphis plantaginea (Passerini). The inoculative introduction of the specific elder aphid Aphis sambuci L. (Homoptera: Aphididae) in late March 2002 and again in 2003 led to the complete hedgerow turning into an early and productive alternative prey reservoir for indigenous syrphids. The species Scaeva pyrastri (L.), S. selenetica (Meigen), Syrphus ribesii (L.), S. vitripennis Meigen, Epistrophe eligans (Harris), E. nitidicollis (Meigen), Platycheirus scutatus (Meigen), Eupeodes corollae (F.), Meligramma triangulifera (Zetterstedt) and Episyrphus balteatus (De Geer) developed on the elder hedgerow during the spring 2002 taking advantage of the aphid infestation. The season 2003 was characterised by a quite different species abundance pattern as, contrary to the previous year when both monovoltine and polyvoltine species were equally represented, the monovoltine syrphids (Epistrophe spp.) represented the dominant group exploiting the elder aphids. A parallel analysis showed that the faeces of the first adult syrphids observed ovipositing on the elder hedgerow in spring contained digested pollen of mainly apple. Our observations indicate the possibility of establishing a local population of monovoltine syrphids in apple orchards by managing an aphid-infested elder hedgerow, without any additional pollen or nectar producing plants.     

Der Pollen vonUllmannia frumentaria

PalZ - Es werden drei männliche Zapfen derUllmannia frumentaria und ihr Pollen beschrieben. Dabei werden grundsätzliche Fragen des Vergleichs der Sporae in situ mit den Sporae dispersae...     

Haemosporidian Parasites of Antelopes and Other Vertebrates from Gabon,Central Africa

Re-examination, using molecular tools, of the diversity of haemosporidian parasites (among which the agents of human malaria are the best known) has generally led to rearrangements of traditional classifications. In this study, we explored the diversity of haemosporidian parasites infecting vertebrate species (particularly mammals, birds and reptiles) living in the forests of Gabon (Central Africa), by analyzing a collection of 492 bushmeat samples. We found that samples from five mammalian species (four duiker and one pangolin species), one bird and one turtle species were infected by haemosporidian parasites. In duikers (from which most of the infected specimens were obtained), we demonstrated the existence of at least two distinct parasite lineages related to Polychromophilus species (i.e., bat haemosporidian parasites) and to sauropsid Plasmodium (from birds and lizards). Molecular screening of sylvatic mosquitoes captured during a longitudinal survey revealed the presence of these haemosporidian parasite lineages also in several Anopheles species, suggesting a potential role in their transmission. Our results show that, differently from what was previously thought, several independent clades of haemosporidian parasites (family Plasmodiidae) infect mammals and are transmitted by anopheline mosquitoes.