Molecular evidence for single Wolbachia infections among geographic strains of the flour beetle Tribolium confusum

Infections with the rickettsial microorganism Wolbachia are cytoplasmically inherited and occur in a wide range of insect species and several other arthropods. Wolbachia infection often results in unidirectional cytoplasmic incompatibility (CI): crosses between infected males and uninfected females are incompatible and show a reduction of progeny or complete inviability. Unidirectional CI can also occur when males harbouring two incompatible Wolbachia strains are crossed with females infected with only one of the two strains. In the flour beetle Tribolium confusum, Wolbachia infections are of particular interest because of the severity of incompatibility. Typically, no progeny results from the incompatible cross, whereas only partial incompatibility is observed in most other hosts. Werren et al. (1995a) reported that Wolbachia infections in T. confusum consist of two bacterial strains belonging to distinct phylogenic groups, based on PCR amplification and sequence analysis of the bacterial cell division gene ftsZ. However, Fialho & Stevens (1996) showed that eight strains of T. confusum were infected with a single and common incompatibility type. Here we report analysis of the ftsZ gene by specific PCR amplification. Diagnostic restriction enzyme assays revealed no evidence of double infections in 11 geographic strains of T. confusum, including the strain examined by Werren et al. (1995a). Further, sequence analysis of the Wolbachia ftsZ gene and an internal transcribed spacer (ITS) region in two of these strains displayed no nucleotide variation or evidence of polymorphisms. Results suggest that T. confusum is infected with B-group Wolbachia only.

Comparative study of ovomucoid isolated from Muscovy duck (Cairina moschata), domestic goose (Anser anser) and domestic duck (Anas platyrhynchos)

1. Ovomucoids were purified from Muscovy duck, domestic duck and domestic goose. 2. Peptide maps of cyanogen bromide-cleaved ovomucoids from Muscovy duck and domestic duck were very similar to one another, but differed from that of goose. 3. Muscovy duck ovomucoid showed the same protease inhibitory pattern as ovomucoid from domestic duck, inhibiting trypsin in the molar ratio of 1:2 and chymotrypsin 1:1. 4. Inhibitory complexes could be detected between chymotrypsin and ovomucoid from both Muscovy and domestic duck, but not from goose, by using non-denaturing gels. 5. No complexes could be detected between DFP-inactivated chymotrypsin and any of the ovomucoids. 6. The results show that of ovomucoid from Muscovy duck more closely resembles that from domestic duck than goose.

Drosophila Myc is oncogenic in mammalian cells and plays a role in the diminutive phenotype

Biochemical and biological activities of Myc oncoproteins are highly dependent upon their association with another basic region helix-loop-helix/leucine zipper (bHLH/LZ) protein, Max. Our previous observation that the DNA-binding/dimerization region of Max is absolutely conserved throughout vertebrate evolution provided the basis for a yeast two-hybrid interaction screen that led to the isolation of the Drosophila Myc (dMyc1) protein. Structural conservation in regions of known functional significance is consistent with the ability of dMyc1 to interact with vertebrate Max, to transactivate gene expression in yeast cells, and to cooperate with activated H-RAS to effect the malignant transformation of primary mammalian cells. The ability of P-element-mediated ectopic expression of dmyc1 to reverse a subset of the phenotypic alterations associated with the diminutive mutation suggests that diminutive may correspond to dmyc1. This finding, along with the localization of dmyc1 expression to zones of high proliferative activity in the embryo, implicates dMyc1 as an integral regulator of Drosophila growth and development.

Contractile properties and myosin heavy chain composition of newborn rat soleus muscles at different stages of postnatal development

This study was undertaken to correlate some of the functional characteristics with the myofibrillar composition in myosin heavy chain isoforms on newborn and adult rat soleus muscles. The following postnatal ages were chosen in order to determine the role of innervation in the establishment of the mature muscle phenotype: before (postnatal day 6), when (postnatal day 12), and after (days 17 and 23) the monosynaptic innervation appeared. The steady state of definitive innervation was controlled on adult muscles (i.e. approximately 13 weeks). Muscle maturation was followed by ATPase staining and fibre diversity was observed at postnatal day 12. The functional properties of skinned bundles isolated from newborn rats were determined by Calcium/Strontium activation characteristics (Tension/pCa and pSr relationships). From postnatal days 6 to 17, the Soleus bundles exhibited Calcium/Strontium activation characteristics intermediate between slow and fast fibre populations previously described in muscles. At day 23, the Calcium/Strontium activation characteristics of the soleus were closer to those of a slow type. Moreover, we observed a decrease in Ca affinity concomitant with the installation of the monosynaptic innervation, and an increase of the slow type I during postnatal development. Finally, this work reported a greater correlation between the Calcium/Strontium activation parameters and the myosin heavy chain isoform composition at the postnatal days when the mature monosynaptic innervation pattern occurred.

Retinopathy and vision loss in insulin-dependent diabetes in Europe. The EURODIAB IDDM Complications Study

PURPOSE

To assess the frequency of retinopathy and vision loss in patients with insulin-dependent diabetes mellitus and their relations to potentially modifiable risk factors.

METHODS

The authors conducted a multicenter cross-sectional study of diabetic complications and their risk factors using standardized methods of assessment. The sample was comprised of 3250 insulin-dependent diabetic patients (1668 men, 1582 women) aged 15 to 60 years with mean (standard deviation) duration of diabetes of 14.7 (9.3) years from 31 European diabetes centers; 2991 of the patients were eligible for retinal photography. Visual acuity was measured using the Snellen chart. Retinopathy was evaluated by retinal photographs (two fields per eye) graded at a central facility. Glycated hemoglobin (HbA1c), cholesterol, triglyceride, fibrinogen, von Willebrand factor, and urinary albumin excretion rate were assessed at a single location.

RESULTS

Corrected visual acuity was greater than or equal to 1.0 in both eyes in 69.7% of patients and less than or equal to 0.1 in the best eye in 2.3%. Factors significantly related to vision loss were age, duration of diabetes, glycated hemoglobin (HbA1c), and level of retinopathy. Mild nonproliferative retinopathy was found in 25.8% of the patients, moderate-severe nonproliferative retinopathy in 9.8% of the patients, and proliferative retinopathy in 10.6% of the patients. After adjustment for age, duration of diabetes, HbA1c, and albumin excretion rate, significant risk factors for moderate-severe nonproliferative retinopathy were blood pressure and triglyceride, and risk factors for proliferative retinopathy were triglyceride and fibrinogen.

CONCLUSION

Vision loss is a common complication of patients with insulin-dependent diabetes, with diabetic retinopathy an important cause. Apart from poor glycemic control, several other potentially modifiable risk factors for retinopathy may be important, including elevated blood pressure, plasma triglyceride, and fibrinogen. In view of the possible barriers to the full implementation of strict glycemic control in this type of diabetes, additional strategies for the prevention and slowing of progression of retinopathy should be investigated, such as blood pressure and lipid lowering therapies.

Bringing order to chaos. A framework for understanding and treating female sexual abuse survivors

One out of three women in the United States has been sexually abused by the age of 18. The legacy of the trauma influences, for example, the survivor's ability to trust others, to recognize appropriate boundaries, and to form intimate relationships. The dynamics of the therapeutic relationship can engender intense responses and activate many of the feelings from the original trauma. This article presents a framework that describes and explains the connections between past sexual abuse, the survivor's present symptoms, and the ways that these influence the transference and countertransference. The frame-work can help clinicians conceptualize the interplay between the sexual abuse and the treatment process. The therapist will therefore be able to avoid some problems in the therapy and better manage those that do arise.

Mouse RT6 locus 1 and rat RT6.2 are NAD+. Arginine ADP-ribosyltransferases with auto-ADP-ribosylation activity

We report that rat RT6.2 and recombinant mouse Rt6 locus 1 proteins possess auto-ADP-ribosyltransferase activity and that Rt6, but not RT6, catalyzes the ADP-ribosylation of exogenous histones. Based on NH2OH sensitivity, it appeared that the ADP-ribose was attached to arginine residues on proteins. We also observed that the NAD+ concentration in culture medium correlates inversely with the proliferation of rat RT6+ T cells. The data suggest that lymphocyte surface ADP-ribosyltransferases could be involved in signaling and immunoregulatory processes.

Role of nonspecific cross-reacting antigen, a CD66 cluster antigen, in activation of human granulocytes

Nonspecific cross-reacting antigen (NCA) is the name of a family of highly glycosylated bacterial-binding receptors found on human granulocytes and other tissues. These glycoproteins are members of the immunoglobulin supergene family and are related structurally to carcinoembryonic antigen. In this study, we demonstrate that ligation of granulocyte NCA results in the activation of the cells, as measured by degranulation and the flux of intracellular calcium. These studies further the proposition that NCA has a function in the immune response of granulocytes against bacterial infections.

Excess mortality and its relation to hypertension and proteinuria in diabetic patients. The world health organization multinational study of vascular disease in diabetes

OBJECTIVE

To determine the extent that mortality in IDDM and NIDDM patients is in excess of that of the general population and examine its relation to hypertension and proteinuria in diabetic patients.

RESEARCH DESIGN AND METHODS

A stratified random sample of 4,714 diabetic patients aged 35-55 years participating in the World Health Organization Multinational Study of Vascular Disease in Diabetes has been followed up from 1975 to 1987. Excess mortality, compared with the background population, was assessed in terms of standardized mortality ratios (SMRs) for each of the 10 international cohorts. The relationship between excess mortality and proteinuria/hypertension was examined by diabetes type and sex.

RESULTS

SMRs were in general higher in patients with IDDM (ranging from 188 to 686 for men and from 336 to 790 for women) than with NIDDM (from 138 to 370 for men and from 126 to 435 for women). For both diabetes types and in both sexes, SMRs decreased with increasing age and increased with increasing diabetes duration. Patients with both hypertension and proteinuria experienced a strikingly high mortality risk: 11-fold for men with IDDM and 18-fold for women with IDDM and 5-fold for men with NIDDM and 8-fold for women with NIDDM. Even in the absence of proteinuria and hypertension, SMRs were significantly increased in both IDDM (284 men and 360 women) and NIDDM (192 men and 236 women) patients.

CONCLUSIONS

Considerable international differences were found not only in mortality rates for the two types of diabetes but also in the extent of excess mortality among centers. IDDM patients had a high excess mortality in comparison with the general population. The significant excess mortality was demonstrated even in patients without proteinuria and without hypertension for both sexes and diabetes types.

Some repair-deficient mutants of Dictyostelium discoideum display enhanced susceptibilities to bleomycin

Dictyostelium discoideum, a soil eukaryote, is highly resistant to DNA-damaging agents; repair mutants are more susceptible. Susceptibility to bleomycin, produced by Streptomyces verticillus, is greater for mutants which are susceptible to other agents than for resistant strains. The high potential for DNA repair may result from the need to cope with chemicals produced by other soil microorganisms.

Structure-function relationship of soleus muscle fibres from the rhesus monkey

Functional and structural properties of rhesus monkey skinned fibres were studied in order to examine the relationship between calcium/strontium (Ca/Sr) activation characteristics and protein composition. The fibres were classified according to their Ca/Sr affinity into slow (61%) and fast groups (39%). According to the myosin isoform composition, two additional hybrid types were defined. Thus, four profiles were characterized: two corresponding to slow (S) and fast (F) isoforms and two corresponding to a mixed proportion of slow and fast isoforms. They were called hybrid slow (HS) or hybrid fast (HF) based on the predominant myosin isoform. Tension/pCa parameters and maximal shortening velocities were determined. S fibres showed a higher pCa threshold and affinity as well as shallower slopes of their tension/pCa curve than did F fibres. HS and HF fibres exhibited tension/pCa curves which were positioned close to those of S and F fibres, respectively. No significant difference was observed between S and HS fibres or between F and HF fibres. Maximal shortening velocity values were higher for fibres expressing predominantly fast myosin isoforms. We suggest than when both S and F isoforms of myofibrillar proteins are expressed in a muscle fibre, the functional properties are mainly governed by the predominant isoform.