The Role of Community Pharmacies in Providing Access to HIV Post-exposure Prophylaxis (PEP)

HIV affects an estimated 1.2 million individuals in the United States and is disproportionately concentrated among African Americans, Latinos, and people of multiple races. Post-exposure prophylaxis (PEP) substantially decreases HIV transmission when started within 72 h after exposure, but problems of accessibility have hindered its widespread usage in communities at risk for HIV infection. Pharmacy-initiated PEP access was first permitted in New York City in 2017, allowing pharmacists to provide a 7-day supply of PEP without a prescription for consumers at high risk for HIV infection. It was expected that the broad reach and accessibility of community pharmacies would increase timely access to PEP for all individuals, especially those who already face significant barriers to accessing the healthcare system. Since then, eleven other states have followed suit and expanded the scope of outpatient pharmacy practice in order to increase the availability of HIV PEP but prescribing laws in over 75% of the US have not been changed. Much of the existing literature on HIV prevention focuses on PrEP access barriers with limited information on PEP access in the US. In this paper, we review the current status of pharmacist-initiated PEP in the US as part of the End the HIV Epidemic (EHE) initiative.

A Case of Daptomycin-Induced Rhabdomyolysis: A Life and Limb Threatening Complication

Surgical site infections (SSIs) contribute to patient morbidity and health expenditure. An increasing elderly population, the expanding use of implants in surgical procedures, drug-resistant microorganisms, and patient-related comorbidities all contribute to SSIs. Daptomycin is an antibiotic known to cause rhabdomyolysis, a life-threatening complication that may lead to acute compartment syndrome (ACS). We present a case of a patient treated with daptomycin for a penile-implant infection complicated by rhabdomyolysis and ACS of his bilateral forearms. He underwent emergent fasciotomies and retained function in his upper extremities long-term. It is vital that physicians closely monitor patients treated with IV-daptomycin therapy and educate patients on alarm symptoms to allow for prompt recognition of life and limb-saving treatments. Orthopedic surgeons should always have a high index of suspicion for ACS and should be aware of the relationship between rhabdomyolysis and ACS.

We are at Full Capacity": Social care workers persisting through work-related stress in a new immigrant settlement context in the United States

Cities without a prior established history of Latina/o migration are experiencing the fastest rate of growth in new immigrants in the United States (Wainer, A tale of two cities (and a town): Immigrants in the Rust Belt, 2013; Lichter & Johnson, Immigrant gateways and Hispanic migration to new destinations. International Migration Review, 43, 496, 2009). These new immigrant settlement cities experience the challenge of adapting their social care context to become more responsive to the needs of immigrants. Yet as cities and social care organisations struggle to keep up with the "lag" time in the availability of culturally and linguistically responsive resources and services, social care providers often work in conditions of scarcity in a social care context that is often lacking in its ability to fully respond to the needs of immigrants. Literature indicates that such conditions of scarcity can lead to work related stress, burn-out, and can have a negative impact on the quality of services delivered by social care workers. Yet little is known regarding social care providers' motivations and responses to work stress; and how providers may positively respond and persist in their jobs despite such stressors. This study conducted in the new immigrant settlement city of Baltimore from 2014 to 2016, utilises semi-structured interviews to qualitatively explore the personal motivational beliefs, workplace and demographic factors associated with buffering stress and frustration among social care workers in a new immigrant settlement city (N = 29). Findings highlight important motivational and work-related factors that appear to minimise the impact of stress and frustration for social care providers and can be used in the development of burn-out interventions as well as improving quality of services for vulnerable populations such as, immigrants, especially in low-resource new immigrant settlement contexts.

Human lysosomal acid lipase inhibitor lalistat impairs Mycobacterium tuberculosis growth by targeting bacterial hydrolases

Lalistat inhibits growth of Mycobacterium tuberculosis in bacterial culture as well as in infected macrophages.

Genetics of fruit body production in higher basidiomycetes II. Monokaryotic and dikaryotic fruiting in schizophyllum commune

In the wood destroying fungus Schizophyllum commune, a well known subject for genetic studies, fruit bodies are produced not only in the course of the sexual cycle but also asexually. Sexual fruiting requires the establishment of a dikaryon which is under the control of the incompatibility factors A and B. Asexual fruiting, however, starts directly from a monokaryon. The initiation of monokaryotic fruiting requires the presence of a single gene leading to the differentiation of fruit body initials. The action of at least two more genes is required for the further morphogenetic steps resulting eventually in the production of fruit bodies which differ in shape from dikaryotic fruit bodies. As a consequence of a mitosis their basidia produce two spores only. The three genes responsible for monokaryotic fruiting are pleiotropic and determine synergistically the timing of dikaryotic fruiting within a range between 6 to 20 d or longer. A fourth gene was found which codes epistatically for the formation of dome-like masses of stromatic tissue, thus directing morphogenesis into a side track.

Isolation and characterization of mitochondrial DNA from the alkane yeast Saccharomycopsis lipolytica

Mitochondrial (mt) DNA of the alkane yeast, Saccharomycopsis lipolytica, was isolated. Its buoyant density in CsCl was found to be of 1.687 g/cm(3), indicating a GC content of 27.5% and its melting point Tm = 79.5 °C, indicating a GC content of 24.9%. The corresponding values for nuclear (n) DNA, are 1.709 g/cm(3) (GC: 49.5%) and Tm = 90.5 (GC: 51.7%) respectively. Electron microscopy revealed that mtDNA has a circular structure with a contour length of about 14.5 µm corresponding to 45.5 kb per molecule. The size estimated from restriction analyses performed with 7 endonucleases was 48.35 kb/molecule. A restriction map was constructed, using the cleavage data of 4 endonucleases.

Transformation to senescence with plasmid like DNA in the ascomycete Podospora anserina

In the ascomycete Podospora anserina senescence through strain aging is under nucleo-cytoplasmic control and inducible in juvenile mycelia by an 'infective principle' transferred after cytoplasmic contact via anastomoses. A specific DNA called plasmid-like (pl) DNA, present exclusively in aging mycelia, was found to be identical with this 'infective principle', since it was possible to transform juvenile protoplasts to senescence by using purified p1DNA. Therefore a specific function may be attributed to this ccc DNA. Its direct involvement in a genetically programed senescence is confirmed and its development as a vector for transfer of genetic information in eukaryotes can be undertaken.

Plasmid-like DNA is part of mitochondrial DNA in Podospora anserina

As previously reported, a ccc DNA with a contour length of 0.75 µm and molecular weight of 2.4 kb (termed plasmid-like, p1DNA) is the causative agent of senescence in the fungus Podospora anserina. Its postulated location in mtDNA was proved correct by the following experiments: 1. Restriction analysis of mtDNA resulted in different molecular weights for both, juvenile (95 kb) and senescent (30 kb) mtDNA. The construction of a detailed restriction map made evident the fact that senescent mtDNA comprises only a part of its juvenile counterpart. 2. Hybridization experiments (Southern blots) between (3)H-labelled plDNA and mtDNA cleaved by restriction juvenile mtDNA are homologous to plDNA. 3. Fine mapping experiments (construction of restriction maps and heteroduplex experiments) between plDNA integrated into a bacterial vector and its postulated equivalent, derived from juvenile mtDNA and also integrated into a bacterial vector, allowed a precise determination of the site of plDNA insertion within the juvenile mtDNA. All of these data fit into a previously published model in which, during aging, plDNA is excised from mtDNA and becomes autonomous for replication and function.

Extrachromosomal genetics of Cephalosporium acremonium : I. characterization and mapping of mitochondrial DNA

DNA analysis of Cephalosporium acremonium revealed that this important fungus for biotechnology contains, apart from chromosomal DNA, two types of extrachromosomal DNA which may be useful for the development of a homologous vector system: 1. Plasmid-like (pl) DNA consisting of circular molecules, but of rather heterogeneous buoyant density and restriction pattern. In contrast to Podospora pl DNA it is not associated with mitochondrial DNA. 2. Mitochondrial (mt) DNA consisting of the smallest circular molecules (26.7 kb) known so far in filamentous fungi. It contains unique cleavage sites for at least 3 restriction endonucleases. A detailed physical map of mtDNA was constructed. A genetics map was also established by hybridization with rho(-) DNA of Saccharomyces cerevisiae. Thus sufficient information for the construction of a mitochondrial vector is now available.

Extrachromosomal genetics of Cephalosporium acremonium : II. Development of a mitochondrial DNA hybrid vector replicating in Saccharomyces cerevisiae

In order to facilitate strain improvement by concerted breeding in the cephalosporin producing imperfect filamentous fungus Cephalo sporium acremonium, it is attempted to develop a eukaryotic vector for molecular cloning based on mitochondrial (mt) DNA.Fragments of mtDNA from C. acremonium were inserted into a yeast/bacterial hybrid plasmid (pDAM1) lacking a eukaryotic replicon. Six hybrid plasmids were obtained each containing a different mt fragment which together comprise about 60% of the total mtDNA. One of these recombinant plasmid vectors (pCP2) showed a high replication efficiency which is comparable to that of vectors containing yeast 2 μm DNA. This plasmid therefore fulfills the requirements for practical application.

Development of a eukaryotic cloning system in Podospora anserina : I. Long-lived mutants as potential recipients

In developing a system for molecular cloning with the Podospora anserina plasmid (p1DNA) it is necessary to find recipient strains which are resistant to p1DNA mediated senescence. Three long lived double mutants which fail to exhibit spontaneous aging were genetically and biochemically analysed. All mutants were infected with p1DNA. The mutant ca viv became irreversibly senescent and therefore was not further tested. The second mutant, gr viv showed some symptoms of aging but never died. The third strain i viv remained resistant to aging from p1DNA infection and has thus proven to be the best host strain available for molecular cloning in this system.A DNA analysis of the latter two strains revealed: 1. There is no difference from the wild strain with respect to the structure of mtDNA and the integration site of the p1DNA. 2. Of the two strains, only i viv contains free p1DNA in its mitochondria but in low amounts if compared to the wild strain. These experimental results are interpreted as follows: 1. The gr viv strain does not liberate spontaneously the p1DNA from mtDNA, but following infection is able to replicate and express this plasmid and therefore is a potential host for transformation. 2. The i viv strain liberates the mitochondrial plasmid but does not express senescence even when infected with p1DNA. Therefore, this strain is an ideal recipient for transformation provided a marker other than senescence is cloned.

The mitochondrial plasmid of Podospora anserina: A mobile intron of a mitochondrial gene

In the ascomycete Podospora anserina strain ageing (senescence) is caused by a mitochondrial plasmid. In juvenile mycelia it is an integral part of the mtDNA and becomes liberated during ageing. The nucleotide sequence of this plasmid and of its flanking regions was determined. It consists of 2,539 by and contains an un identified reading frame (URF) originating in the adjacent mtDNA upstream of excision point 1. Within the URF a putative 48 by autonomously replicating sequence (ars) was identified. At both excision sites of the plasmid there are two short nonidentical interrupted palindromes and a few base pairs apart from these palindromes, both upstream and downstream, two short inverted repeats are localised. The experimental data make it evident that the mt plasmid is an intron of the cytochrome c oxidase gene (subunit I) which may be excised at the DNA level and thus become the mobile infective agent causing senescence. The concept of this mobile intron and current hypotheses concerning the relationship between introns and transposons are stressed.

Extrachromosomal genetics of Claviceps purpurea : I. Mitochondrial DNA and mitochondrial plasmids

In order to establish a system for gene cloning in the ergot fungus Claviceps purpurea mitochondrial DNA was purified from two wild strains and four descendants of production strains. A characterization of the mt DNA with respect to buoyant density, molecular weight (45 kb corresponding to acontour lenght of 14 μm) showed no differences. However, considerable differences were detected in the restriction pattern, with the exception of two commercial strains of possibly common origin. From this it follows that restriction patterns of mt DNA may be used as finger prints to identify related strains.In one of the wild strains plasmids associated with the mitochondria were found. A characterization of two species p11 and p12 having molecular weights of 6.6 and 5.3 kb revealed that these genetic units are linear having respective contour lengths of 2.1 and 1.7 μm. According to Southern blot analyses both plasmids show homology to each other, but not to the mitochondrial "chromosome". Accordingly, p11 and p12, despite localization in the mitochondria, are evidently not an integral part of the mt "chromosome". The possibility to use the mt DNA and mitochondrial plasmids to establish a vector system for molecular cloning in imperfect strains of Claviceps purpurea has been pointed out.

[A comparative study of the hepatic transit time (HTT) of different ultrasound contrast agents in patients with liver metastases and healthy controls]

PURPOSE

Liver metastases lead to a shortening of the HTT of an echo enhancer. Studies using SonoVue™ also showed a shortening of the HTT in healthy controls. Hence the HTT depends on the applied contrast agent. We examined whether the HTT of SonoVue™, Luminity™ und Levovist™ is useful to discriminate between patients with and without liver metastases.

MATERIALS AND METHODS

We compared the arteriovenous HTT of Levovist™, Sonovue™ und Luminity™ in 20 patients with liver metastases and in 15 controls. An Acuson Sequoia™ ultrasound system was used. The HTT results from the difference of the arrival time of the microbubbles in the hepatic artery and a hepatic vein.

RESULTS

Using Levovist™ six patients and three controls had to be excluded from further analysis. The arrival time was undetectable. The mean HTT values in healthy controls were: Levovsit™ 14.75 sec (SD ± 2.53 sec), SonoVue™ 9.27 sec (SD ± 2.41 sec) and Luminity™ 9.2 sec (SD ± 2.34 sec). In patients the mean HTT values were: Levovist™ 9.89 sec (SD ± 1.04 sec), SonoVue™ 6.28 sec (SD ± 2.41 sec) and Luminity™ 6.33 sec (SD ± 1.37 sec). Using a cut off of 8 sec for SonoVue™ and Luminity™, the sensitivity to exclude liver metastases was 75% and 80%.

CONCLUSION

The mean HTT values of all contrast agents were shorter in patients. Levovist™ showed a longer HTT in patients and controls than Luminity™ and SonoVue™. Levovist™ showed the best separation between patients and controls but some patients and controls had to be excluded. The HTT could still be a useful tool to exclude liver metastases but the HTT depends on the contrast agent and the applied contrast technique.

The mitochondrial IMP peptidase of yeast: functional analysis of domains and identification of Gut2 as a new natural substrate

The mitochondrial inner membrane peptidase IMP of Saccharomyces cerevisiae is required for proteolytic processing of certain mitochondrially and nucleus-encoded proteins during their export from the matrix into the inner membrane or the intermembrane space. The membrane-associated signal peptidase complex is composed of the two catalytic subunits, Imp1 and Imp2, and the Som1 protein. The IMP subunits are thought to function in membrane association, interaction and stabilisation of subunits, substrate specificity, and proteolysis. We have analysed inner membrane peptidase mutants and substrates to gain more insight into the functions of various domains and investigate the basis of substrate recognition. The results suggest that certain conserved glycine residues in the second and third conserved regions of Imp1 and Imp2 are important for stabilisation of the Imp complex and for the proteolytic activity of the subunits, respectively. The non-conserved C-terminal parts of the Imp subunits are important for their proteolytic activities. The C-terminal region of Imp2, comprising a predicted second transmembrane segment, is dispensable for the stability of Imp2 and Imp1, and cannot functionally substitute for the C-terminal segment of Imp1. Alteration of the Imp2 cleavage site in cytochrome c(1) (from A/M to N/D) reveals the specificity of the Imp2 peptidase. In addition, we have identified Gut2, the mitochondrial FAD-dependent glycerol-3-phosphate dehydrogenase, as a new substrate for Imp1. Failure to cleave the Gut2 precursor may contribute to the pet phenotype of certain imp mutants. Gut2 is associated with the inner membrane, and is essential for growth on glycerol-containing medium. Suggested functions of the analysed residues and domains of the IMP subunits, characteristics of the cleavage sites of substrates and implications for the phenotypes of imp mutants are discussed.

Autocrine phosphorylation of p70(S6k) in response to acute stretch in myotubes

Phosphorylation of 70-KDa S6 kinase (p70(S6k)) is correlated with in vivo skeletal muscle hypertrophy. Experiments tested whether mechanical stretch is sufficient to increase p70(S6k) phosphorylation in skeletal myotubes. Immediately following stretch, there was a small increase in p70(S6k) phosphorylation (63.2 +/- 8.5%) with maximal phosphorylation at 3 h (129.5 +/- 22.2%) and it remained elevated through 24 h (46.0 +/- 17.2%). To test whether an autocrine mechanism is involved, unstretched myotubes were incubated with medium from the stretch group for 10 min. Conditioned medium resulted in the phosphorylation of p70(S6k) in unstretched myotubes (92.8 +/- 28.9%) to levels comparable to the 3-h stretch group. These data indicate that p70(S6k) is phosphorylated in stretched myotubes via a mechanism that most likely involves an autocrine signaling pathway.

Transcriptional regulation in response to exercise

Much progress has been made in recent years into understanding molecular mechanisms by which transcription is regulated following changes in physiological stimuli. This review has tried to focus on what is known about four specific physiological challenges--mechanical load, intracellular calcium, hypoxia, and redox state. Because of our biased interest in exercise, it was our goal to review these relatively well-studied systems so that we might provide insight into potential mechanisms that govern exercise-induced transcriptional changes. What becomes obvious, when reaching the end of this review, is that there are many common themes among the different physiological responses described. Some examples include the activation of IEGs, such as c-jun and c-fos, the phosphorylation of the transcription factor CREB, and the importance of the serum response element and the serum response factor. These commonalities across the different physiological systems suggest a certain redundancy or shared mechanism(s) for regulating transcription in response to physiological stimuli. While very little is known at this time about how exercise regulates transcription, it is an exciting time in this field of research. The recent growth in the molecular biological research literature of more physiologically-based studies provides exciting new molecular and cellular tools for those researchers willing to take on the challenge of understanding the complex mechanisms of exercise-induced adaptations.

Som1, a third component of the yeast mitochondrial inner membrane peptidase complex that contains Imp1 and Imp2

The mitochondrial inner membrane peptidase Imp is required for proteolytic processing of the mitochondrially encoded protein Cox2, the nucleus-encoded Cyt b2, Mcr1, and Cyt c1, and possibly other proteins, during their transport across the mitochondrial membranes. The peptidase contains two catalytic subunits, Imp1 and Imp2. The small protein Soml was previously shown to affect the function of Imp1, but the precise role of Soml remained unknown. Using mutants deleted for IMP1, IMP2 and SOM1, we show here that the Som1 protein is absent in the imp1delta mutant, whereas the level of the Imp1 subunit of the peptidase is only slightly reduced in the soml null mutant. The Soml protein is not essential for proteolytic processing of Cyt b2, while the two other known Imp1 substrates, Cox2 and Mcr1, are not processed in the absence of Som1. Proteolytic processing of Cyt c1 by the Imp2 subunit, and of Ccp by an as yet unidentified peptidase, is not impaired in the som1 deletion mutant. By crosslinking and co-immunoprecipitation assays we demonstrate that the Imp1 and Som1 proteins physically interact. We conclude from our results that stabilisation of Som1 and correct Imp1 function is mediated by a direct interaction between the Imp1 and Som1 proteins, suggesting that Som1 represents a third subunit of the Imp peptidase complex.

Disruption of six open reading frames on chromosome X of Saccharomyces cerevisiae reveals a cluster of four essential genes

In this study we report the construction and basic phenotypic analysis of six Saccharomyces cerevisiae deletion mutants. The open reading frames (ORFs) YJL008C (gene symbol CCT8), YJL010C, YJL011C, YJL012C, YJL017W, and YJL020C from chromosome X have been disrupted by integration of deletion cassettes, comprising the bacterial KanMX4 marker gene and terminal long (LFH) or short (SFH) flanking sequences that are homologous to the 5' and 3' untranslated regions of the respective ORFs. For correct disruption of ORF YJL008C, it was necessary to construct a deletion cassette flanked by 300-350 bp long target guide sequences by LFH-PCR. Transformations using ORF YJL008C gene disruption cassettes synthesized by standard SFH-PCR exclusively resulted in false-positive or multiple integration events, probably because seven additional genes homologous to CCT8 exist in the yeast genome. The other five ORFs have been disrupted using cassettes generated by SFH-PCR, comprising terminal homologous regions of approximately 50 bp to each target site. Correct genomic integration of the reporter modules was verified by analytical PCR and Southern hybridization. Deletion of YJL008C, YJL010C, YJL011C, and YJL012C was found to be lethal, as shown by sporulation and tetrad analysis. This result is in contrast to the finding that only 16-20% of the genes in S. cerevisiae are estimated to be essential. The four essential genes described in this work are clustered, while the two other non-essential ORFs are separated by further ORFs. Although the two viable deletion mutants were tested against 60 different inhibitors, heavy metal ions and salts, no phenotype could be detected that co-segregated with the deletion during meiosis.

The CACC box and myocyte enhancer factor-2 sites within the myosin light chain 2 slow promoter cooperate in regulating nerve-specific transcription in skeletal muscle

Previous experiments showed that activity of the -800-base pair MLC2slow promoter was 75-fold higher in the innervated soleus (SOL) compared with the noninnervated SOL muscles. Using in vivo DNA injection of MLC2slow promoter-luciferase constructs, the aim of this project was to identify regulatory sites and potential transcription factors important for slow nerve-dependent gene expression. Three sites within the proximal promoter (myocyte enhancer factor-2 (MEF2), E-box, and CACC box) were individually mutated, and the effect on luciferase expression was determined. There was no change in luciferase expression in the SOL and extensor digitorum longus (EDL) muscles when the E-box was mutated. In contrast, the MEF2 mutation resulted in a 30-fold decrease in expression in the innervated SOL muscles (10.3 versus 0.36 normalized relative light units (RLUs)). Transactivation of the MLC2slow promoter by overexpressing MEF2 was only seen in the innervated SOL (676,340 versus 2,225,957 RLUs; p < 0.01) with no effect in noninnervated SOL or EDL muscles. These findings suggest that the active MLC2slow promoter is sensitive to MEF2 levels, but MEF2 levels alone do not determine nerve-dependent expression. Mutation of the CACC box resulted in a significant up-regulation in the EDL muscles (0.23 versus 4.08 normalized RLUs). With the CACC box mutated, overexpression of MEF2 was sufficient to transactivate the MLC2slow promoter in noninnervated SOL muscles (27,536 versus 1, 605,797 RLUs). Results from electrophoretic mobility shift and supershift assays confirm MEF2 protein binding to the MEF2 site and demonstrate specific binding to the CACC sequence. These results suggest a model for nerve-dependent regulation of the MLC2slow promoter in which derepression occurs through the CACC box followed by quantitative expression through enhanced MEF2 activation.

Phosphorylation of p70(S6k) correlates with increased skeletal muscle mass following resistance exercise

High-resistance exercise training results in an increase in muscle wet mass and protein content. To begin to address the acute changes following a single bout of high-resistance exercise, a new model has been developed. Training rats twice a week for 6 wk resulted in 13.9 and 14.4% hypertrophy in the extensor digitorum longus (EDL) and tibialis anterior (TA) muscles, respectively. Polysome profiles after high-resistance lengthening contractions suggest that the rate of initiation is increased. The activity of the 70-kDa S6 protein kinase (p70(S6k)), a regulator of translation initiation, is also increased following high-resistance lengthening contractions (TA, 363 +/- 29%; EDL, 353 +/- 39%). Furthermore, the increase in p70(S6k) activity 6 h after exercise correlates with the percent change in muscle mass after 6 wk of training (r = 0.998). The tight correlation between the activation of p70(S6k) and the long-term increase in muscle mass suggests that p70(S6k) phosphorylation may be a good marker for the phenotypic changes that characterize muscle hypertrophy and may play a role in load-induced skeletal muscle growth.

The Saccharomyces cerevisiae SOM1 gene: heterologous complementation studies, homologues in other organisms, and association of the gene product with the inner mitochondrial membrane

The small nuclear gene SOM1 of Saccharomyces cerevisiae was isolated as a multicopy suppressor of a mutation in the IMP1 gene, which encodes the mitochondrial inner membrane peptidase subunit 1 (Imp1). Analysis revealed that Som1 and Imp1 are components of a mitochondrial protein export system, and interaction between these two proteins is indicated by the genetic suppression data. Here we describe the identification of a gene from Kluyveromyces lactis, which restores respiratory function to a S. cerevisiae SOM1 deletion mutant at 28 degrees C. The sequence of the K. lactis gene predicts a protein product of 8.1-kDa, comprising 71 amino acid residues, with a putative mitochondrial signal sequence at its N-terminus. The protein is 50% identical to its S. cerevisiae counterpart. The expression pattern of a homologous sequence in Leishmania major suggests a more general role for SOM1 in mitochondrial biogenesis and protein sorting. The various Som1 proteins exhibit a highly conserved region and a remarkable pattern of cysteine residues. A protein of the expected size was transcribed and translated in vitro. The Som1 protein was detected in fractions of S. cerevisiae enriched for mitochondria and found to be associated with the inner mitochondrial membrane.

SOM 1, a small new gene required for mitochondrial inner membrane peptidase function in Saccharomyces cerevisiae

IMP1 encodes a subunit of the mitochondrial inner membrane peptidase responsible for the proteolytic processing of cytochrome oxidase subunit 2 (Cox2) and cytochrome b2 (Cytb2). The molecular defect in an imp1 mutation and the characterisation of a high-copy-number suppressor is described. A deletion of the suppressor region causes respiration deficiency. The DNA sequence revealed three very small overlapping ORFs. Constructs which carried termination codons within the ORFs or lacked ATG initiation codons still retained complementing activity on a high-copy-number plasmid. Nevertheless, the possibility that the suppressor acts at DNA or RNA level could be excluded. Subcloning of the ORFs, complementation analysis in low-copy-number plasmids and transcript mapping identified the 222 bp ORF as the suppressor gene designated SOM1. The SOM1 gene is transcribed into a 375 bp polyadenylated RNA and the deduced amino acid sequence predicts a small protein of 8.4 kDa with no significant sequence similarity to known proteins. In the som1 deletion mutant, proteolytic processing of the Cox2 precursor is prevented and Cytb2 is strongly reduced. SOM1 represents a new small gene which encodes a novel factor that is essential for the correct function of the Imp1 peptidase and/or the protein sorting machinery.

Exercise down-regulates hepatic lipogenic enzymes in food-deprived and refed rats

The effects of an acute bout of prolonged exercise on the activities of several hepatic lipogenic enzymes and the abundance of fatty acid synthase (FAS) mRNA were evaluated using a food deprivation-refeeding protocol in which diets contained 50% of the energy from either fructose or cornstarch. Food was withheld from male rats for 48 h and refed for 0, 4, 8, 12, 24 or 48 h. At each time point, half of each dietary group was subjected to a single bout of treadmill running until exhaustion and killed immediately. The other half of each group rested without food for the same amount of time before being killed. Exercise significantly decreased FAS activity by 57, 46, 10, 26 and 70% at 4, 8, 12, 24 and 48 h of refeeding, respectively, in the fructose-fed rats; and by 70 and 63% at 24 and 48 h of refeeding, respectively, in the cornstarch-fed rats. Activities of L-type pyruvate kinase and glucose 6-phosphate dehydrogenase were significantly decreased after exercise in the fructose-fed, but not cornstarch-fed rats. In rested rats, FAS mRNA abundance increased approximately fourfold above the unfed levels after 8 and 12 h of refeeding. Exercise attenuated the diet-induced increases in FAS mRNA abundance. At 8 h of refeeding, both cornstarch- and fructose-fed exercised rats had 71% (P < 0.05) of the FAS mRNA levels of their rested counterparts; at 12 h, these exercised rats showed only 46 and 27% (P < 0.05) of FAS mRNA levels compared with rested rats fed the same diet. We conclude that dietary induction of FAS activity and mRNA abundance can be inhibited by prolonged exercise, suggesting that exercise may influence FAS transcription and/or mRNA stability.

PET1402, a nuclear gene required for proteolytic processing of cytochrome oxidase subunit 2 in yeast

The nuclear mutation pet ts1402 prevents proteolytic processing of the precursor of cytochrome oxidase subunit 2 (cox2) in Saccharomyces cerevisiae. The structural gene PET1402 was isolated by genetic complementation of the temperature-sensitive mutation. DNA sequence analysis identified a 1206-bp open reading frame, which is located 215 bp upstream of the PET122 gene. The DNA sequence of PET1402 predicts a hydrophobic, integral membrane protein with four transmembrane segments and a typical mitochondrial targeting sequence. Weak sequence similarity was found to two bacterial proteins of unknown function. Haploid cells containing a null allelle of PET1402 are respiratory deficient.

7-Chloro-4-nitrobenzofurazan inactivates chloroplast H(2+)-ATPase by modification of different tyrosines, depending on the presence of ATP

The addition of 7-chloro-4-nitrobenzofurazan (NBD) to isolated CF1 at pH 7.5 leads to one tyrosine-bound NBD molecule per CF1 in one of the three beta-subunits, concomitantly with the inhibition of the ATPase activity. Addition of ADP prior to NBD-incubation protected the ATPase activity and reduced binding of NBD to beta-subunits. The addition of MgATP prior to modification did not result in protection against modification of the beta-subunit as well as preservation of activity. Cleavage of the NBD-labelled subunits with cyanogen bromide, followed by analysis of the labelled peptides, led to detection of a 14C-labelled peptide of 7 kDa in both cases (+/- ATP-preincubation). Sequence analysis of this peptide showed that in ATP-incubated CF1, tyr beta 328 was modified with NBD-Cl, whereas the ATP free sample contained no NBD bound to this tyrosine. Further digestion of the labelled peptide with protease V8 (Staphylococcus aureus) followed by sequence analysis of the radioactive labelled peptide, led to the detection of beta-tyr362 as the modified amino acid in case of ATP-free CF1. Both tyrosines are closely related to a proposed nucleotide binding region of beta.

Nerve-dependent and -independent patterns of mRNA expression in regenerating skeletal muscle

Muscle regeneration was used to assess the roles of innervation and intrinsic genetic information in the acquisition of predominant slow and fast contractile protein mRNA profiles in adult skeletal muscle. Rat soleus (slow) and EDL (fast) muscles were allowed to regenerate in the presence and absence of their respective slow and fast nerves. Levels of mRNAs encoding fast, slow, and cardiac contractile protein isoforms were quantitatively determined at specific times during regeneration. All muscles initially expressed a heterogeneous pattern of fast, slow, and cardiac isoform mRNAs during myotube formation. Subsequently, the EDL muscle made a transition to a predominantly fast profile of mRNAs which was independent of innervation. The mRNA profile for the noninnervated regenerating soleus muscle was similar to both the innervated and the noninnervated EDL muscle profile. Thus, the decision to express predominantly fast isoform mRNAs is intrinsic to in vivo muscle regeneration with the fast nerve not appearing to be informative. In contrast, acquisition of a slow mRNA profile is dependent on the presence of a slow nerve. The mRNAs encoding slow isoforms from all of the contractile protein gene families are upregulated during the period of reestablishment of neuromuscular transmission. Additionally, there is no concomitant down-regulation of the fast isoform mRNAs upon reinnervation in the soleus regenerate. We propose that information both intrinsic to the muscle and supplied by the in vivo environment acts to provide potential isoform mRNA options to the regenerating muscle.

Adjuvant arthritic (AA) rats exhibit enhanced endotoxin-induced plasma TNF (EIPT) levels

Adjuvant arthritis (AA) was induced in male Lewis rats by a single FCA (M. butyricum) injection into the tail. At various time periods post FCA injection, AA and control rats were anesthetized and administered E. coli endotoxin (30 mg/kg, i.v.). Plasma samples were obtained at 30, 60, 90, 120 and 150 min following endotoxin administration and assayed for TNF alpha levels by ELISA. Compared to control rats, AA rats exhibited enhanced EIPT levels (706% of control, p < 0.05) which was associated with the onset of inflammatory lesions on days 12-14 post FCA, and remained significantly elevated (> 300% of control, p > 0.05) for at least 30 days post FCA. There were no significant correlations between EIPT levels and hindpaw volumes or body weights. The results of this study support previous observations that AA is associated with macrophage activation and suggest that EIPT levels in AA rats may be a useful parameter for the evaluation of novel antiarthritic agents.

Immunization of owl monkeys with a recombinant protein containing repeated epitopes of a Plasmodium falciparum glycophorin-binding protein

A Plasmodium falciparum glycophorin binding protein (GBP-130) has been implicated in protective immunity to malaria. The gene for GBP-130 encodes a protein containing 11 tandemly repetitive 50 amino acid units. We report an immunization trial in Aotus monkeys using a recombinant DNA protein containing three of these 50 amino acid repeats. When administered with aluminum hydroxide, this antigen induced low levels of antibodies that reacted with the recombinant protein by ELISA and with parasite antigens in immunoblot and immunofluorescence assays, but not by immunoprecipitation. When administered with Freund's complete adjuvant, this antigen induced high levels of antibodies that reacted in ELISA, immunoblot, immunofluorescence, and immunoprecipitation assays. Serum from immunized monkeys did not inhibit parasite growth, and protection from intravenous challenge with P. falciparum-infected erythrocytes was not observed in any experimental group. These results suggest that the repetitive region of GBP-130 is not a useful vaccine candidate.

Antiserum to a novel peptide sequence reacts selectively with epithelial subpopulations

A synthetic peptide corresponding to a novel protein sequence isolated from bovine kidney was used to immunize rabbits. When applied to Western blots of bovine kidney extracts, antiserum to this peptide recognizes proteins with molecular weights of 23 and 18 KD. Immunohistochemical examination of a variety of bovine and rat tissues with this antiserum revealed a unique distribution of immunoreactivity with the intermediate layers of a variety of stratified epithelia, in addition to renal glomeruli. The pattern of reactivity differed from previously described epithelial markers such as cytokeratins. These results indicate that this antiserum may be useful as a tool for the identification of cells of the intermediate layer of stratified epithelia and, as such, may aid in the study of this differentiating/proliferating tissue compartment.

Integrative transformation of the ascomycete Podospora anserina: identification of the mating-type locus on chromosome VII of electrophoretically separated chromosomes

Protoplasts of wild-type strain s and a long-lived extrachromosomal mutant (AL2) of the ascomycete Podospora anserina were transformed using a plasmid (pAN7-1) which contains the hygromycin B phosphotransferase gene (hph) of Escherichia coli under the control of Aspergillus nidulans regulatory sequences. After optimizing the transformation procedure, transformation efficiencies of 15-21 transformants/micrograms plasmid DNA were obtained. Using a second selectable vector (pBT3), which contains the beta-tubuline gene of a benomyl-resistant Neurospora crassa mutant, the co-transformation rate was determined. Southern blot hybridization experiments revealed that the transforming plasmid became integrated into the genome of the recipient either as a single copy or as multiple copies. In addition, the data from molecular as well as from classical genetic analyses indicated that in independent transformants vector integration occurred at different positions. The mitotic and meiotic stability of transformants proved to be dependent on the number of integrated plasmid copies. Genetic analyses revealed a transformant in which the integrated vector is closely linked to the mating-type locus. Fractionation of whole chromosomes by pulsed field gel electrophoresis and subsequent hybridization of the immobilized DNAs against radiolabelled vector sequences indicated the largest of seven chromosomes as the chromosome containing the integrated vector and thus the mating-type locus.

Improved transformation frequency and heterologous promoter recognition in Aspergillus niger

Wild-type strains of Aspergillus niger were transformed with integrative vectors. The number of stable transformants varied from approximately 20-30/micrograms up to 17,000/micrograms using acetamide and hygromycin B selection, respectively. The introduction of deletions of 5' and 3' non-coding regions of the acetamidase gene (amdS+) revealed that these sequences influenced the number of transformants. The molecular characterization of A. niger transformants revealed that several copies of the vectors were tandemly integrated into the nuclear DNA. These oligomers were stably inherited, even after 100 days of growth on non-selective medium. The expression of the vector-encoded genes was confirmed by evidence from the mRNAs and corresponding proteins encoded by the selectable marker genes.

Molecular cloning and characterization of the recA gene of Methylomonas clara and construction of recA deficient mutant

The recA gene of the methylotrophic bacterium Methylomonas clara has been isolated from a genomic library by hybridization with the Escherichia coli recA gene. Its complete nucleotide sequence consists of 1029 bp encoding a polypeptide of 342 amino acids. Nucleotide sequence analysis of the M. clara recA gene revealed extensive homologies to recA genes from E. coli and Pseudomonas aeruginosa. Part of the physiological activity of the M. clara RecA protein has become evident in that E. coli recA mutant HB101 is complemented. The cloned recA gene has been modified in vitro by site-specific mutagenesis and by insertion of a kanamycin-resistance gene cassette into the recA coding sequence. M. clara recA mutants were obtained by replacement of the active recA gene by an in-vitro inactivated gene copy.

Heterologous gene expression on the linear DNA killer plasmid from Kluyveromyces lactis

Linear hybrid plasmids based on the killer plasmid pGKL1 from Kluyveromyces lactis were obtained by in vivo recombination in Saccharomyces cerevisiae. Like pGKL1, the hybrids are located in the cytoplasm, have terminal inverted repeats (TIR) and possess covalently linked proteins at their 5' ends. The construction of cytoplasmic hybrid plasmids is based on the use of a pGKL1 promoter to control the marker gene used for recombination. Nuclear promoters are not recognised in the cytoplasm.

In organello replication and viral affinity of linear, extrachromosomal DNA of the ascomycete Ascobolus immersus

Linear, extrachromosomal DNA's of the filamentous fungus Ascobolus immersus are localized within the mitochondria. These linear plasmids have no homology to the high molecular weight mtDNA (hmw mtDNA). For analysis of plasmid replication an in organello DNA synthesis system was developed, in which radionucleotides were incorporated into intact mitochondria. Plasmid DNA is labelled preferentially in this system. From replication analysis of a specific plasmid there is evidence of a virus-like protein-primed replication. Sequence analysis of this plasmid reveals that a viral DNA polymerase is encoded. Thus, these genetic elements presumably are viral remnants rather than true plasmids.

In vivo construction of linear vectors based on killer plasmids from Kluyveromyces lactis: selection of a nuclear gene results in attachment of telomeres

Linear vectors based on plasmids pGKL1 and pGKL2 from Kluyveromyces lactis were obtained by in vivo recombination in Saccharomyces cerevisiae and selected for integration of the nuclear LEU2 gene. The linear hybrid molecules obtained had no proteins attached to their 5' ends, as is found for native pGKL plasmids. However, telomere-specific sequences were added to the ends of pGKL1. In contrast to the cytoplasmically localized pGKL plasmids, the newly obtained linear hybrid vectors probably replicate within the nucleus and provide evidence that the nuclear LEU2 gene cannot be expressed in the cytoplasm.

Sleeping sickness in the Lambwe Valley in 1978

Even though tsetse control measures were discontinued in the Lambwe Valley in 1974 the prevalence of Rhodesian sleeping sickness remained at low levels. A survey conducted in 1978 verified a low prevalence of disease (0.1%). Thirty-four per cent of the individuals tested were positive for malaria with the highest prevalence (44%) in children aged 0-9 years. Thirteen of 1340 individuals (0.97%) tested and found negative for sleeping sickness in 1978 developed the disease by 1985. Fourteen individuals with moderate titres (2+) in the IFAT but who showed no evidence of disease were traced and found to be alive and well seven years later. Three of these patients still had positive titres but the others had converted to negative. Sera from four patients infected and treated in 1978 were also positive, but only one of five patients treated in 1977 reacted in the test. The CFT as described did not appear useful as a diagnostic test.

New recombinant linear DNA-elements derived from Kluyveromyces lactis killer plasmids

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Mitochondrial DNA rearrangements are correlated with a delayed amplification of the mobile intron (plDNA) in a long-lived mutant of Podospora anserina

A new long-lived mutant of Podospora anserina has been isolated and characterized. Its longevity is maternally inherited as revealed by reciprocal crosses. A molecular analysis resulted in the identification of an amplified DNA species (designated pAL2-1) with homology to mitochondrial DNA (mtDNA). The presence of this DNA species is correlated with mtDNA rearrangements and a delayed amplification of the mobile intron (plDNA).