Engineering O-O Species in Boron Nitrous Nanotubes Increases Olefins for Propane Oxidative Dehydrogenation

Boron nitride (BN) has been widely studied as an efficient catalyst for oxidative propane dehydrogenation (OPDH). Oxygen-containing boron species (e.g., BO·, B(OH)_xO_3-x) are generally considered as the active centers in BN for OPDH. Here, we show an effective progressive substitution strategy toward the development of boron-oxygen-nitrogen nanotubes (BONNTs) enriched with O-O species as a highly active, selective, and stable catalyst for OPDH. At 525 °C, an olefin yield of 48.6% is achieved over BONNTs with a propane conversion of 64.4%, 2.8 times that of boron nitrogen nanotubes (BNNTs). Even after reaction for 150 h (475 °C), BONNTs exhibit good olefin yield. Both the B(OH)_xO_3-x and O-O species that coexist in the BONNT catalyst are demonstrated as active centers, which differs from the B(OH)_xO_3-x one in BNNTs. Based on catalytic results, propane and oxygen alternate treatment experiments, and theoretical calculations, the O-O center is more favorable for producing both propylene (C₃₌) and ethylene (C₂₌), which experiences a dehydration pathway and two possible reaction paths with a lower energy barrier to yield olefins, while B(OH)_xO_3-x is mainly responsible for producing few C₃₌.

Approaching Superfoldable Thickness-Limit Carbon Nanofiber Membranes Transformed from Water-Soluble PVA

Recent progress in flexible electronics has attracted tremendous attention. However, it is still difficult to prepare superfoldable conductive materials with good biocompatibility, high sensing sensitivities, and large specific surface areas. It is expected that biomimetic methods and water-soluble precursors like poly(vinyl alcohol) (PVA) for electrospinning will be utilized to solve the above problems. Inspired by the multistage water management process of a spider spinning dragline silk, we have established a combined biomimetic technique, hydrocolloid electrospinning coupled with temperature gradient dehydration, with a carbonization technique. PVA-driven superfoldable carbon nanofiber membranes (PVA-SFCNFMs) have been prepared that not only possess a >60% micropore ratio and a 1368.8 m²/g specific surface area but also can withstand 180° real folding for 100 000 cycles, approaching the thickness limit without structure fracture. Furthermore, these membranes provide highly sensitive sensing and superior biocompatible interfaces. The molecular mechanism to improve carbon conversion and the folding mechanism to obtain "three-level dispersing stress" for the PVA-SFCNFMs have been proposed.

The inhibition of Mpro, the primary protease of COVID-19, by Poria cocos and its active compounds: a network pharmacology and molecular docking study

Poria cocos is a traditional Chinese medicine (TCM) that can clear dampness, promote diuresis, and strengthen the spleen and stomach. Poria cocos has been detected in many TCM compounds that are used for COVID-19 intervention. However, the active ingredients and mechanisms associated with the effect of Poria cocos on COVID-19 remain unclear. In this paper, the active ingredients of Poria cocos, along with their potential targets related to COVID-19, were screened using TCMSP, GeneCards, and other databases, by means of network pharmacology. We then investigated the active components, potential targets, and interactions, that are associated with COVID-19 intervention. The primary protease of COVID-19, Mpro, is currently a key target in the design of potential inhibitors. Molecular docking techniques and molecular dynamics simulations demonstrated that the active components of Poria cocos could bind stably to the active site of Mpro with high levels of binding activity. Pachymic acid is based on a triterpene structure and was identified as the main component of Poria cocos; its triterpene active component has low binding energy with Mpro. The pachymic acid of Mpro activity was further characterized and the IC₅₀ was determined to be 18.607 μmol L⁻¹. Our results indicate that pachymic acid exhibits a certain inhibitory effect on the Mpro protease.

The inhibition of Mpro, the primary protease of COVID-19, by Poria cocos.

Assessment of Apparent Internal Carotid Tandem Occlusion on High-Resolution Vessel Wall Imaging: Comparison with Digital Subtraction Angiography

BACKGROUND AND PURPOSE

Not all tandem occlusions diagnosed on traditional vascular imaging modalities, such as MRA, represent actual complete ICA occlusion. This study aimed to explore the utility of high-resolution vessel wall imaging in identifying true ICA tandem occlusions and screening patients for their suitability for endovascular recanalization.

MATERIALS AND METHODS

Patients with no signal in the ICA on MRA were retrospectively reviewed. Two neuroradiologists independently reviewed their high-resolution vessel wall images to assess whether there were true tandem occlusions and categorized all cases into intracranial ICA occlusion, extracranial ICA occlusion, tandem occlusion, or near-occlusion. DSA classified patient images into the same 4 categories, which were used as the comparison with high-resolution vessel wall imaging. The suitability for recanalization of occluded vessels was evaluated on high-resolution vessel wall imaging compared with DSA.

RESULTS

Forty-five patients with no ICA signal on MRA who had available high-resolution vessel wall imaging and DSA images were included. Among the 34 patients (34/45, 75.6%) with tandem occlusions on DSA, 18 cases also showed tandem occlusions on high-resolution vessel wall imaging. The remaining 16 patients, intracranial ICA, extracranial ICA occlusions and near-occlusions were found in 2, 6, and 8 patients, respectively, on the basis of high-resolution vessel wall imaging. A total of 20 cases (20/45, 44.4%) were considered suitable for recanalization on the basis of both DSA and high-resolution vessel wall imaging. Among the 25 patients deemed unsuitable for recanalization by DSA, 11 were deemed suitable for recanalization by high-resolution vessel wall imaging.

CONCLUSIONS

High-resolution vessel wall imaging could allow identification of true ICA tandem occlusion in patients with an absence of signal on MRA. Findings on high-resolution vessel wall imaging can be used to screen more suitable candidates for recanalization therapy.

VCP/p97/Cdc48, A Linking of Protein Homeostasis and Cancer Therapy

VCP/p97/Cdc48, a member of the ATPases associated with diverse cellular activities (AAA) family, is necessary for the endoplasmic-reticulum-associated protein degradation (ERAD) pathway to maintain protein homeostasis. Overwhelming proteotoxic stress drove cancer cells to enhance VCP/p97/Cdc48-associated ERAD to maintain protein homeostasis for survival, demonstrating that VCP/p97/Cdc48 expression was positively correlated with cancer prognosis. More studies revealed that targeting VCP/p97/Cdc48 could be a potential target in cancer therapy. CB-5083, a novel inhibitor of VCP/p97/Cdc48, is in clinical trials as the first VCP/p97/Cdc48- inhibiting drug for cancer therapy. Here, we discuss the relationship between VCP/p97/Cdc48, ERAD, protein homeostasis and cancer therapy.

Characterization and adsorption of a Lactobacillus plantarum virulent phage

Bacteriophage infection of lactic acid bacteria is considered one of the biggest worldwide problems in the food industry. Bacteriophages may cause negative effects on the fermentation of various dairy-based products. A virulent bacteriophage was isolated from an abnormal fermentation liquid of Lactobacillus plantarum IMAU10120. The characterization and influence of temperature, pH, divalent cations, and chloramphenicol on the adsorption ability of this phage were evaluated. The results showed that this phage belonged to the Siphoviridae family. It exhibited a burst time of 135 min and a burst size of approximately 215 counts expressed per milliliter per infective center. No significant effect was shown to influence its viability and adsorption at 10 to 37°C. More than 90% of phages exhibited infectivity from pH 5 to 9. Divalent ions and chloramphenicol did not have a significant influence on the adsorption of this phage. The information obtained in this study will enrich the database of lactobacilli virulent phages and provide a basis of information for the control of phages in the food fermentation industry.

Stronger selective constraint on downstream genes in the oxidative phosphorylation pathway of cetaceans

The oxidative phosphorylation (OXPHOS) pathway is an efficient way to produce energy via adenosine triphosphate (ATP), which is critical for sustaining an energy supply for cetaceans in a hypoxic environment. Several studies have shown that natural selection may shape the evolution of the genes involved in OXPHOS. However, how network architecture drives OXPHOS protein sequence evolution remains poorly explored. Here, we investigated the evolutionary patterns of genes in the OXPHOS pathway across six cetacean genomes within the framework of a functional network. Our results show a negative correlation between the strength of purifying selection and pathway position. This result indicates that downstream genes were subjected to stronger evolutionary constraints than upstream genes, which may be due to the dual function of ATP synthase in the OXPHOS pathway. Additionally, there was a positive correlation between codon usage bias and omega (ω = dN/dS) and a negative correlation with synonymous substitution rate (dS), indicating that the stronger selective constraint on genes (with less biased codon usage) along the OXPHOS pathway is attributable to an increase in the rate of synonymous substitution. Surprisingly, there was no significant correlation between protein-protein interactions and the evolutionary estimates, implying that highly connected enzymes may not always show greater evolutionary constraints. Compared with that observed for terrestrial mammals, we found that the signature of positive selection detected in five genes (ATP5J, LHPP, PPA1, UQCRC1 and UQCRQ) was cetacean-specific, reflecting the importance of OXPHOS for survival in hypoxic, aquatic environments.

Virtual classroom helps medical education for both Chinese and foreign students

AIMS

The rapid development of computer and internet technology has a strong influence over one's quality of education within different fields of study. To determine the potential benefits of introducing internet into medical school classes, a pilot study was conducted in three different Chinese medical schools.

MATERIALS AND METHODS

Seven hundred and eight medical school undergraduates, 385 dental school students and 366 foreign students were randomly recruited to complete a self-administered questionnaire. The contents included personal information, current usage of computer and internet, and attitudes towards the computerised teaching methods. Two forum groups were created using instant message software and were randomly assigned to two classes, allowing students to freely ask or discuss questions with the help of their teachers in these two virtual classrooms.

RESULTS

All 1539 questionnaires were accepted and analysed. Although there were some differences between Chinese and foreign undergraduates, both group of students were highly proficient in internet usage and navigation. Overwhelmingly, 88.37% of the students owned a computer and frequently logged onto the internet. Most of them believed that the internet is a helpful adjunct to their studies and held positive attitudes towards computerised teaching. Compared to the classes that were not assigned internet forums, the two experimental classes performed significantly better on the examination.

CONCLUSIONS

Our results suggest that computerised teaching methods have significant potential to assist in learning for both Chinese and foreign medical undergraduates.

Neonatal Overfeeding in Female Mice Predisposes the Development of Obesity in their Male Offspring via Altered Central Leptin Signalling

The prevalence of obesity among child-bearing women has increased significantly. The adverse consequences of maternal obesity on the descendants have been well accepted, although few studies have examined the underlying mechanisms. We investigated whether neonatal overfeeding in female mice alters metabolic phenotypes in the offspring and whether hypothalamic leptin signalling is involved. Neonatal overfeeding was induced by reducing the litter size to three pups per litter, in contrast to normal litter size of 10 pups per litter. Normal and neonatally overfed female mice were bred with normal male mice, and offspring of overfeeding mothers (OOM) and control mothers (OCM) were generated. We examined body weight, daily food intake, leptin responsiveness and the number of positive neurones for phosphorylated-signal transducer and activator of transcription 3 (pSTAT3) along with neuropeptide Y (NPY) in the arcuate nucleus of the hypothalamus (ARH) and NPY in the nucleus tractus solitarius (NTS) of the brain stem. The body weight and daily food intake of OOM were significantly higher than those of OCM. Leptin significantly reduced food intake and increased the number of pSTAT3 positive neurones in the ARH of OCM mice, whereas no significant changes in food intake and pSTAT3 neurones were found in leptin-treated OOM mice. The number of NPY neurones in the ARH and NTS of the OOM mice was significantly higher than that of OCM mice. The results of the present study indicate that the obese phenotype from mothers can be passed onto the subsequent generation, which is possibly associated with hypothalamic leptin resistance.

Defects in articular cartilage metabolism and early arthritis in fibroblast growth factor receptor 3 deficient mice

Fibroblast growth factor (FGF) receptor 3 has been identified as a key regulator of endochondral bone development and of post-natal bone metabolism through its action on growth plate chondrocytes and osteoblasts, respectively. It has also been shown to promote chondrogenesis and cartilage production by cultured pre-chondrogenic cells in response to FGF18. In the current studies, we show that the absence of signaling through Fgfr3 in the joints of Fgfr3(-/-) mice leads to premature cartilage degeneration and early arthritis. Degenerative changes in cartilage matrix included excessive proteolysis of aggrecan core protein and type II collagen, as measured by neo-epitope immunoreactivity. These changes were accompanied by increased expression of metalloproteinase MMP13, type X collagen, cellular hypertrophy and loss of proteoglycan at the articular surface. Using a novel micro-mechanical indentation protocol, it was shown that articular cartilage in the humeral head of 4-month-old Fgfr3(-/-) mice was less resistant to compressive force and less stiff than that of littermate controls. These results identify Fgfr3 signaling as a potential target for intervention in degenerative disorders of cartilage metabolism.

Nicotine metabolism and CYP2A6 allele frequencies in Koreans

CYP2A6 is a major catalyst of nicotine metabolism to cotinine. Previously, we demonstrated that the interindividual difference in nicotine metabolism is related to a genetic polymorphism of the CYP2A6 gene in Japanese. To clarify the ethnic differences in nicotine metabolism and frequencies of CYP2A6 alleles, we studied nicotine metabolism and the CYP2A6 genotype in 209 Koreans. The cotinine/nicotine ratio of the plasma concentration 2 h after chewing one piece of nicotine gum was calculated as an index of nicotine metabolism. The genotypes of CYP2A6 gene (CYP2A6*1A, CYP2A6*1B, CYP2A6*2, CYP2A6*3, CYP2A6*4 and CYP2A6*5) were determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism or allele specific (AS)-PCR. There were ethnic differences in the allele frequencies of CYP2A6*1A, CYP2A6*1B, CYP2A6*4 and CYP2A6*5 between Koreans (45.7%, 42.8%, 11.0% and 0.5%, respectively) and Japanese (42.4%, 37.5%, 20.1% and 0%, respectively, our previous data). Similar to the Japanese, no CYP2A6*2 and CYP2A6*3 alleles were found in Koreans. The homozygotes of the CYP2A6*4 allele (four subjects) were completely deficient in cotinine formation, being consistent with the data among Japanese. The heterozygotes of CYP2A6*4 tended to possess a lower metabolic ratio (CYP2A6*1A/CYP2A6*4, 4.79 +/- 3.17; CYP2A6*1B/CYP2A6*4, 7.43 +/- 4.97) than that in subjects without the allele (CYP2A6*1A/CYP2A6*1A, 7.42 +/- 6.56; CYP2A6*1A/CYP2A6*1B, 9.85 +/- 16.12; CYP2A6*1B/CYP2A6*1B, 11.33 +/- 9.33). The subjects who possess the CYP2A6*1B allele appeared to show higher capabilities of cotinine formation. It was confirmed that the interindividual difference in nicotine metabolism was closely related to the genetic polymorphism of CYP2A6. The probit plot of the metabolic ratios in Koreans (8.73 +/- 11.88) was shifted to a higher ratio than that in the Japanese (3.78 +/- 3.09). In each genotype group, the Korean subjects revealed significantly higher metabolic ratios than the Japanese subjects. The ethnic difference in cotinine formation might be due to environmental and/or diet factors as well as genetic factors.

[Effect of rare earth elements on the seedling ratio of crops]

The effects of rare earth elements(REEs) on the relative seedling ratio of three crops(rice, rape and soybean) in three soil(red soil, yellow fluvo-aquic soil and yellow cinnamon soil) were studied according to OECD method, and the LC50 were obtained. Toxicity effect of REEs on rice was minimum among the crops tested. The toxicity on crops in yellow cinnamon soil was lower, whereas on soybean in yellow fluvo-aquic soil and on rape in red earth were higher.

Antenatal syphilis in sub-Saharan Africa: missed opportunities for mortality reduction

PURPOSE

Between 4-15% of pregnant women are believed to be infected with syphilis in sub-Saharan Africa. Active infection with syphilis in pregnant women results in foetal or infant death or disability for 50-80% of affected pregnancies, and is a major cause of adult morbidity as well. Antenatal syphilis screening is cheap and effective; however, it is often poorly implemented in countries with high syphilis risk. This study sought to estimate the missed opportunities for antenatal syphilis screening in sub-Saharan Africa.

METHODS

Survey data were collected from 22 ministries of health in sub-Saharan Africa, complemented by data from published sources and key informants. Informants described their country's policies and experience with antenatal syphilis screening and estimated their national syphilis screening rates.

FINDINGS

Seventy-three percent of women are reported by WHO to receive antenatal care in the study countries. Of women in antenatal care, 38% were estimated by survey respondents to be screened for syphilis. Costs and the organization of services were the principal reported obstacles to screening. With syphilis seroprevalence estimated at 8.3%, approximately 1 640 000 pregnant women with syphilis are undetected annually, including 1 030 000 women who attend antenatal care.

DISCUSSION

Syphilis testing and treatment is a cost-effective intervention that deserves much greater attention, particularly in sub-Saharan Africa and other countries where syphilis infection is high.

[Cluster analysis methods appropriate for classification of drought-resistant wheat ecotypes]

The appropriate cluster analysis methods for classification of drought-resistant wheat ecotypes were investigated, based on the analysis of 21 morphologic and agronomic characters of 15 winter wheat cultivars. According to the proximity degree to the results from experts experiences, the cluster results using original data were orderly better than those using Varimax orthogonal rotation, Promax skew intersection rotation, and principal component analysis with phenotypic mean's correlation matrix. The results using Euclidean distance were greater than those using Mahalanobis distance. The clustering methods of correspondent analysis and fuzzy cluster were better than those of nearest distance, furthest distance or group average method (UPGMA). Among all cluster results from various methods combined, the two cluster results from the fuzzy cluster using original data and from the correspondence analysis method were closest to the results of experts' experience. Based on both comparisons of results and examination of the performance of different strategies with several statistical properties, the two methods mentioned above were also acceptable.

The overlapping angB and angG genes are encoded within the trans-acting factor region of the virulence plasmid in Vibrio anguillarum: essential role in siderophore biosynthesis

Products encoded in the trans-acting factor (TAF) region are necessary for the biosynthesis of anguibactin and for maximal expression of iron transport and biosynthesis genes in the plasmid-encoded iron-scavenging system of Vibrio anguillarum. Here we identify angB, a locus located in the TAF region, which encodes products essential for anguibactin biosynthesis. We demonstrate that a 287-amino-acid polypeptide, encoded by angB and designated AngB, has an isochorismate lyase activity necessary for the synthesis of 2, 3-dihydroxybenzoic acid, an anguibactin biosynthesis intermediate. Complementation of various angB mutations provided evidence that an additional, overlapping gene exists at this locus. This second gene, designated angG, also has an essential biosynthetic function. The angG gene directs the expression of three polypeptides when overexpressed in Escherichia coli, all of which are translated in the same frame as AngB. The results of site-directed mutagenesis and in vivo phosphorylation experiments suggest that the carboxy-terminal end of AngB and the AngG polypeptide(s) function as aryl carrier proteins involved in the assembly of the anguibactin molecule. Our results also show that the regulatory functions of the TAF are encoded in a region, TAFr, which is distinct from and independent of the angB and angG genes.

[Protective efficacy of H2 strain live attenuated hepatitis A vaccines in an outbreak of hepatitis A]

OBJECTIVE

To investigate the protective efficacy of H(2) strain live attenuated hepatitis A vaccine (H(2)-strain vaccine) locally produced in an outbreak of hepatitis A (HA).

METHODS

A nonrandomized controlled design was used in a trial for HA vaccination. Five thousand five hundred and fifty-one children at preschool classes and at grades 1 - 3 of primary schools were selected in 14 villages. Epidemiological and serological methods were used to evaluate its protective efficacy of the vaccines and serum immunoglobulin M against hepatitis A virus (IgM anti-HAV) was detected with ELISA for 271 subjects in vaccinated group and 341 in the control one.

RESULTS

An outbreak of HA occurred one year after the vaccination with 26 cases in the vaccinated group, including one vaccine-related case with an attack rate of 0.28% (1/356), and 25 cases in the control group with an attack rate of 5.92% (25/422). The protective efficacy of vaccines was 95.27% (95% confidence interval of 85.83% to 104.72%). Positivity of IgM anti-HAV, i.e., newly-infected cases, was 4.43% (12/271) in the vaccinated group and 13.38% (42/314) in the control group, respectively. Clinically apparent cases accounted for 8.33% (1/12) and 50.00% (21/42) in newly-infected cases in vaccinated and control groups, respectively.

CONCLUSION

Vaccination with H(2) strain vaccines locally produced was effective in reducing occurrence of HA during its outbreak, but not so effective in preventing its infection. A booster dose of HA vaccine should be vaccinated for children in adequate time.

Solution structure of carnobacteriocin B2 and implications for structure-activity relationships among type IIa bacteriocins from lactic acid bacteria

Carnobacteriocin B2 (CbnB2), a type IIa bacteriocin, is a 48 residue antimicrobial peptide from the lactic acid bacterium Carnobacterium pisicola LV17B. Type IIa bacteriocins have a conserved YGNGVXC sequence near the N-terminus and usually contain a disulfide bridge. CbnB2 seemed to be unique in that its two cysteines (Cys9 and Cys14) could be isolated as free thiols [Quadri et al. (1994) J. Biol. Chem. 26, 12204-12211]. To establish the structural consequences of the presence or absence of a disulfide bridge and to investigate if the YGNGVXC sequence is a receptor-binding motif [Fleury et al. (1996) J. Biol. Chem. 271, 14421-14429], the three-dimensional solution structure of CbnB2 was determined by two-dimensional (1)H nuclear magnetic resonance (NMR) techniques. Mass spectroscopic and thiol modification experiments on CbnB2 and on model peptides, in conjunction with activity measurements, were used to verify the redox status of CbnB2. The results show that CbnB2 readily forms a disulfide bond and that this peptide has full antimicrobial activity. NMR results indicate that CbnB2 in trifluoroethanol (TFE) has a well-defined central helical structure (residues 18-39) but a disordered N terminus. Comparison of the CbnB2 structure with the refined solution structure of leucocin A (LeuA), another type IIa bacteriocin, indicates that the central helical structure is conserved between the two peptides despite differences in sequence but that the N-terminal structure (a proposed receptor binding site) is not. This is unexpected because LeuA and CbnB2 exhibit >66% sequence identity in the first 24 residues. This suggests that the N-terminus, which had been proposed [Fleury et al. (1996) J. Biol. Chem. 271, 14421-14429] to be a receptor binding site of type IIa bacteriocins, may not be directly involved and that recognition of the amphiphilic helical portion is the critical feature.

Characterization of the interaction between Fur and the iron transport promoter of the virulence plasmid in Vibrio anguillarum

The expression of iron transport genes fatDCBA in Vibrio anguillarum strain 775 is negatively regulated by two iron-responsive repressors, the Fur protein and the antisense RNA, RNAalpha. Here we report the identification of the promoter for the iron transport genes and studied the interaction between the V. anguillarum Fur protein and this promoter. The iron transport promoter was localized in a region approximately 300 base pairs upstream of fatD by both primer extension and S1 mapping analysis. High activity of the promoter was measured in response to iron depletion in the wild-type strain when a promoter-lacZ fusion was examined, whereas the promoter was constitutive in the Fur-deficient strain. Gel retardation and DNase I footprint analysis showed that Fur binds specifically to two contiguous sites comprising the promoter region and the region downstream of the transcription start site. The identified Fur binding sites showed a low degree of homology to each other as well as to the consensus sequence for the Escherichia coli Fur protein. DNase I footprints pattern suggested a sequential interaction of Fur with these two sites that renders a protection in the template strand and a hypersensitivity to the nuclease in the nontemplate strand. The periodicity of the hypersensitive sites suggested that the promoter DNA undergoes a structural change upon binding to Fur, which might play a role in the repression of gene expression.

IL-15 receptor maintains lymphoid homeostasis by supporting lymphocyte homing and proliferation

The IL-15 receptor alpha subunit (IL-15Ralpha) mediates high-affinity binding of IL-15, a pleiotropic cytokine implicated in the development of innate immune cells. We have generated IL-15Ralpha null (IL-15Ralpha-/-) mice to understand the role of IL-15Ralpha in immune development and function. IL-15Ralpha-/- mice are markedly lymphopenic despite grossly normal T and B lymphocyte development. This lymphopenia is due to decreased proliferation and decreased homing of IL-15Ralpha-/- lymphocytes to peripheral lymph nodes. These mice are also deficient in natural killer cells, natural killer T cells, CD8+ T lymphocytes, and TCRgammadelta intraepithelial lymphocytes. In addition, memory phenotype CD8+ T cells are selectively reduced in number. Thus, IL-15Ralpha has pleiotropic roles in immune development and function, including the positive maintenance of lymphocyte homeostasis.

The complete nucleotide sequence and functional organization of Bacillus subtilis bacteriophage SPP1

The complete nucleotide sequence of the B. subtilis bacteriophage SPP1 is described. The genome is 44,007 bp in size and has a base composition of 43.7% dG + dC. Only 32.2 kb are essential for phage amplification under laboratory conditions. Transcription using only the 'heavy strand' is asymmetric. Eighty-one orfs organized in five early and four late operons were identified. Experiments have shown that 25 orfs are essential. Of the remaining orfs, functions could be predicted for the products of five of the orfs on the basis of comparison of the deduced amino acid sequence to known proteins. Intergenic regions include most of the 5 PE and the 4 PL promoters. Transcripts are polycistronic. Transcription from the PE promoters is mediated by host RP, whereas recognition of the PL promoters requires an additional unidentified phage-encoded product. Translation of mRNA transcribed from most of the orfs seems to be initiated independently, each from its own ribosomal binding and initiation site, although a few cases of coupled translation have been reported. The organization of SPP1 genes involved in the replication, DNA packaging and phage assembly proteins resembles the organization of genes of equivalent regions of different E. coli double-stranded DNA phages. Absence of aa sequence similarity between analogous proteins of different phages suggested that the conserved gene organization is representative of a primordial bacteriophage.

The replisome organizer (G38P) of Bacillus subtilis bacteriophage SPP1 forms specialized nucleoprotein complexes with two discrete distant regions of the SPP1 genome

Initiation of Bacillus subtilis bacteriophage SPP1 DNA replication requires the products of genes 38, 39 and 40 (G38P, G39P and G40P). G38P specifically binds two discrete regions, which are 32.1 kb apart in a linear map of the SPP1 genome. One of these target sites, which maps at the left end of the phage genome, within gene 38, was shown to function as an origin of replication and was therefore termed left origin (oriL). The other site, which lies within a non-coding segment in the late transcribed region on the right end of the genome, was termed oriR. Both sites contain two types of repeated elements (termed Box AB and A + T-rich region). The K(app) for the G38P-oriL DNA and G38P-oriR DNA complexes was estimated to be 1 nM and 4 nM, respectively. G38P binds to the distant oriL and oriR sites cooperatively. DNase I footprinting experiments showed protection by G38P in Box AB, but not in the A + T-rich region. Electron microscopy analysis showed that G38P forms a higher-order nucleoprotein structure with the SPP1 oriL and oriR sites through protein-protein interaction. G38P binding at its cognate sites does not seem to modify the length of the DNA, but to bend it. These results suggest that G38P forms a nucleoprotein complex on the regions where the SPP1 replication origins were previously predicted.

Obstacles to nutrition labeling in restaurants

OBJECTIVE

This study determined the major obstacles that foodservices face regarding nutrition labeling.

DESIGN

Survey questionnaire was conducted in May 1994. In addition to demographic questions, the directors were asked questions addressing willingness, current practices, and perceived obstacles related to nutrition labeling.

SUBJECTS/SETTING

Sixty-eight research and development directors of the largest foodservice corporations as shown in Restaurants & Institutions magazine's list of the top 400 largest foodservices (July 1993).

STATISTICAL ANALYSES PERFORMED

P tests were used to determine significance within a group for the number of foodservices that were currently using nutrition labeling, perceived impact of nutrition labeling on sales, and perceived responsibility to add nutrition labels. Regression analysis was used to determine the importance of factors on willingness to label.

RESULTS

Response rate was 45.3%. Most companies were neutral about their willingness to use nutrition labeling. Two thirds of the respondents were not currently using nutrition labels. Only one third thought that it was the foodservice's responsibility to provide such information. Several companies perceived that nutrition labeling would have a potentially negative effect on annual sales volume. Major obstacles were identified as menu or personnel related, rather than cost related. Menu-related obstacles included too many menu variations, limited space on the menu for labeling, and loss of flexibility in changing the menu. Personnel-related obstacles included difficulty in training employees to implement nutrition labeling, and not enough time for foodservice personnel to implement nutrition labeling.

APPLICATIONS

Numerous opportunities will be created for dietetics professionals in helping foodservices overcome these menu- or personnel-related obstacles.

Bacillus subtilis bacteriophage SPP1 terminase has a dual activity: it is required for the packaging initiation and represses its own synthesis

The B. subtilis bacteriophage SPP1 terminase, encoded by genes 1 and 2, is required for the initiation of headful packaging. The DNA segment to which gene 1 product (G/P) binds includes the pacL and pacR sites and the late PL1 and PL2 promoters from which genes 1 to 7 are transcribed. When SPP1wt or SPP1sus115 (gene 6-) phages were used to infect a B. subtilis sup0 strain, the gene 1 to 7 mRNA synthesis was reduced at late times of infection. This was not observed, however, when either chloramphenicol was added 7 min after infection with SPP1wt or when SPP1sus114 (gene 1-) or SPP1sus19 (gene 2-) were used to infect B. subtilis sup0 cells. These results suggest that the terminase enzyme functions as a repressor of its own transcription. G/P and B. subtilis RNA polymerase (RP) bind to the pacL segment, which contains the PL1 and PL2 promoter region. The binding of G/P to the pacL site does not seem to exclude RP from the promoters, despite of the overlapping of their binding sites. It is likely that the terminase protein does not repress transcription by a mere steric hindrance of RP binding.

Distamycin-induced inhibition of formation of a nucleoprotein complex between the terminase small subunit G1P and the non-encapsidated end (pacL site) of Bacillus subtilis bacteriophage SPP1

The small subunit of the Bacillus subtilis bacteriophage SPP1 terminase (G1P) forms a sequence-specific nucleoprotein complex with the SPP1 non-encapsidated end (pacL site) during initiation of DNA encapsidation. Gel mobility shift assay was used to study the G1P-pacL interaction. Distamycin, a minor groove binder that induces local distortion of the DNA, inhibits G1P-pacL complex formation. The competition of G1P with distamycin for DNA binding at the pacL site is independent of the order of addition of the reactants. Other minor groove binders, such as spermine or Hoechst 33258, which do not distort DNA, failed to compete with G1P for pacL DNA binding. Cationic metals, which generate a repertoire of DNA structures different from that caused by the minor groove binders, can partially reverse the distamycin-induced inhibition of G1P binding to pacL DNA. The major groove binder methyl green, which does not distort sequence-directed bending of pacL DNA, competes with G1P for binding at the pacL site. Our data suggest that the natural sequence-directed bend that exists within the pacL site is the architectural element that facilitates assembly of a nucleoprotein complex and hence initiation of DNA encapsidation by bacteriophage SPP1.

The small subunit of the terminase enzyme of Bacillus subtilis bacteriophage SPP1 forms a specialized nucleoprotein complex with the packaging initiation region

Initiation of SPP1 DNA packaging requires the gene 1 and gene 2 products (G1P and G2P), which are different subunits of the terminase enzyme. G1P specifically recognizes the phage packaging initiation region (pac). The apparent equilibrium constant for the G1P-pac-DNA complex was estimated to be 9 nM. DNase I footprinting experiments reveal that the pac region can be subdivided into three discrete sites (pacL, pacC and pacR). G1P binds co-operatively to the non-adjacent pacL and pacR sites. Several G1P protomers bind to the target sequences which map close to the pac cleavage site (pacC site), but do not overlap with it. G1P interacts in a different fashion with the encapsidated (pacR site) and with the non-encapsidated (pacL site) end of the phage genome. G1P interaction with the intrinsically bent pacL DNA occurs only on one face of the DNA double helix. G1P binding to the pacL and in the pacR region results in a DNA loop. Electron microscopy of purified G1P shows that the protein is an oligomer in solution. G1P binding to the core region of the pacL site could facilitate the formation of a higher-order nucleoprotein structure. This specialized complex would allow the pac DNA to form a loop between binding sites brought together by interaction with G1P. The results presented here suggest that G1P could provide a tool to discriminate the first encapsidated end, which contains pacR, from the non-encapsidated pacL end.

Lead acetate-induced contraction in rabbit mesenteric artery: interaction with calcium and protein kinase C

Animal studies have demonstrated that low-level lead exposure produces hypertension and that lead can cause contraction of vascular smooth muscle directly. The physiological effects of lead have been associated with both stimulation and inhibition of protein kinase C (PKC). Given that vascular smooth muscle contractility is generally enhanced when protein kinase C is activated, we have tested the hypothesis that lead contracts vascular smooth muscle via stimulation of PKC. Helically-cut strips of rabbit mesenteric artery were mounted in muscle baths for measurement of isometric force development. Cumulative addition of lead acetate (10(-10)-10(-3) M) to the muscle bath produced contractions (concentration necessary to produce half-maximal response -log EC50 = 5.16 +/- 0.07). Maximal contraction to lead acetate in arteries denuded of endothelium did not differ from those in intact vessels, supporting the hypothesis that lead-induced contraction is an endothelium-independent event. Contractions to lead acetate were potentiated by the PKC activators, phorbol 12-myristate 13-acetate (TPA; 3 x 10(-7) M) and mezerein (3 x 10(-7) M), as indicated by leftward shifts in the concentration-response curve and increase in the potency of lead (-log EC50 with TPA: 6.94 +/- 0.07; -log EC50 with mezerein: 6.07 +/- 0.04). H-7 (6 x 10(-6) M), an inhibitor of PKC, decreased maximal contraction to lead approximately 65% and slightly, but insignificantly, decreased the potency of lead (-log EC50 = 4.82 +/- 0.1). The inactive phorbol ester, phorbol 12-myristate 13-acetate 4-0-methyl ether (1 x 10(-6) M), did not alter contractile responses to lead (-log EC50 = 4.92 +/- 0.09). Vascular contraction to lead partially depends on extracellular calcium as the L-type voltage-gated calcium channel antagonist, verapamil (3 x 10(-6) M), decreased lead-induced contractions by 50%. These data indicate that lead interacts with PKC in an endothelium-independent, calcium-dependent manner to cause vascular smooth muscle contraction and suggest that lead-induced increases in vascular contractility may play a role in lead-induced hypertension.

M.phi 3TII: a new monospecific DNA (cytosine-C5) methyltransferase with pronounced amino acid sequence similarity to a family of adenine-N6-DNA-methyltransferases

The temperate B.subtilis phages phi 3T and rho 11s code, in addition to the multispecific DNA (cytosine-C5) methyltransferases (C5-MTases) M. phi 3TI and M. rho 11sI, which were previously characterized, for the identical monospecific C5-MTases M. phi 3TII and M. rho 11sII. These enzymes modify the C of TCGA sites, a novel target specificity among C5-MTases. The primary sequence of M. phi 3TII (326 amino acids) shows all conserved motifs typical of the building plan of C5-MTases. The degree of relatedness between M. phi 3TII and all other mono- or multispecific C5-MTases ranges from 30-40% amino acid identity. Particularly M. phi 3TII does not show pronounced similarity to M. phi 3TI indicating that both MTase genes were not generated from one another but were acquired independently by the phage. The amino terminal part of the M. phi 3TII (preceding the variable region 'V'), which predominantly constitutes the catalytic domain of the enzyme, exhibits pronounced sequence similarity to the amino termini of a family of A-N6-MTases, which--like M.TaqI--recognize the general sequence TNNA. This suggests that recently described similarities in the general three dimensional organization of C5- and A-N6-MTases imply divergent evolution of these enzymes originating from a common molecular ancestor.

M.phi 3TII: a new monospecific DNA (cytosine-C5) methyltransferase with pronounced amino acid sequence similarity to a family of adenine-N6-DNA-methyltransferases

The temperate B.subtilis phages phi 3T and rho 11s code, in addition to the multispecific DNA (cytosine-C5) methyltransferases (C5-MTases) M.phi 3TI and M.rho 11sI, which were previously characterized, for the identical monospecific C5-MTases M.phi 3TII and M.rho 11sII. These enzymes modify the C to TCGA sites, a novel target specificity among C5-MTases. The primary sequence of M.phi 3TII (326 amino acids) shows all conserved motifs typical of the building plan of C5-MTases. The degree of relatedness between M.phi 3TII and all other mono- or multispecific C5-MTases ranges from 30-40% amino acid identity. Particularly M.phi 3TII does not show pronounced similarity to M.phi 3TI indicating that both MTase genes were not generated from one another but were acquired independently by the phage. The amino terminal part of the M.phi 3TII (preceding the variable region 'V'), which predominantly constitutes the catalytic domain of the enzyme, exhibits pronounced sequence similarity to the amino termini of a family of A-N6-MTases, which--like M.Taql--recognize the general sequence TNNA. This suggests that recently described similarities in the general three dimensional organization of C5- and A-N6-MTases imply divergent evolution of these enzymes originating from a common molecular ancestor.

Nucleotide sequence and complementation studies of the gene 35 region of the Bacillus subtilis bacteriophage SPP1

Genetic analysis of the Bacillus subtilis bacteriophage SPP1 defective in gene 35 shows that the gene 35 product (G35P) is essential for SPP1 growth. The defect in growth of SPP1tsl17 and SPP1tsl20F at nonpermissive temperature is overcome by wild-type gene 35 expressed from a plasmid. The region where gene 35 maps was cloned and sequenced. Analysis of the nucleotide sequence (5884-bp) around gene 35 revealed 13 open reading frames (orfs). We have assigned the term gene to three of these orfs; gene 35, gene 36, the product of which shares homology with SSB proteins, and gene 38, given the gene order orf 34-orf 34.1-orf 34.2-orf34.3-orf34.4-gene 35-gene 36-orf 36.1-orf 37-orf 37.1-orf 37.2-orf 37.3-gene 38. Gene 35 encodes a protein of 32.0 kDa. By using the T7 promoter-expression system for gene 35 a radioactive band of the expected molecular mass was detected.

Analysis of the Bacillus subtilis bacteriophages SPP1 and SF6 gene 1 product: a protein involved in the initiation of headful packaging

Gene 1 product (G1P) of the related Bacillus subtilis bacteriophages SPP1, SF6, and rho 15 is essential for DNA maturation and packaging. A DNA segment containing gene 1 of phage SF6 or rho 15 origin was cloned and sequenced. SF6 and rho 15 G1P (both with predicted molecular mass of 16.7 kDa) share 71% identity with G1P of SPP1. The G1P of all three phages contains three conserved segments (I, II, and III). Within segments I and II helix-turn-helix DNA binding and nucleotide binding motifs were predicted. G1P of both SPP1 and SF6 origin was purified. SPP1 G1P protein (20.7 kDa), purified from cells overexpressing the cloned gene, purifies together with another polypeptide, having a molecular mass of about 13 kDa. The 13-kDa polypeptide results from a translation start signal within gene 1, and hence was termed SPP1 G1P*. G1P of both SPP1 and SF6 binds specifically to a pac-containing DNA fragment, whereas G1P*, which lacks segment I, does not. Chimeric G1P proteins were obtained by domain swapping between gene 1 of SPP1 and SF6. The results presented here suggest that the G1P DNA binding motif lies in segment I and the major determinant for G1P::G1P interaction might lie in segment II. Segment III and the extended C-terminal part of SPP1 G1P are dispensable. The G1P::G2P interacting region remains uncharacterized.

Analysis of cis and trans acting elements required for the initiation of DNA replication in the Bacillus subtilis bacteriophage SPP1

The development of SPP1 has been studied in several B. subtilis mutants conditionally defective in initiation of DNA replication. Initiation of SPP1 replication is independent of the host DnaA (replisome organizer), DnaB, DnaC and DnaI products, but requires the DnaG (DNA primase) and the DNA gyrase. Furthermore, SPP1 replication is independent of the DnaK (heat shock) protein. The phage-encoded products required for initiation of SPP1 replication have been genetically characterized. Analysis of the nucleotide sequence (3.292 kilobases) of the region where SPP1 initiation replication mutants map, revealed five open reading frames (orf). We have assigned genes 38, 39 and 40 to three of these orfs, which have the successive order gene 38-gene 39-orf39,1-gene 40-orf41. The direction of transcription of the reading frames, the lengths of the mRNAs as well as the transcription start point, upstream of gene 38 (PE2), were identified. Proteins of 29.9, 14.6 and 46.6 kDa were anticipated from translation of gene 38, gene 39 and gene 40, respectively. The purified G38P and G39P have estimated molecular masses of 31 and 15 kDa. G38P and G39P do not share significant identity with primary protein sequences currently available in protein databases, whereas G40P shares substantial homology with a family of DNA primase-associated DNA helicases. G38P binds specifically to two discrete SPP1 DNA restriction fragments (EcoRI-4 and EcoRI-3). The G38P binding site on EcoRI-4 was localized on a 393 bp DNA segment, which lies within the coding sequence of gene 38. The putative binding site on EcoRI-3 was inferred by DNA sequence homology, it maps in a non-coding segment. G39P, which does not bind to DNA, is able to form a complex with G38P. The organization of the SPP1 genes in the gene 38 to gene 40 interval resembles that one found in the replication origin regions of different Escherichia coli double-stranded DNA phages (lambda, phi 80 and P22). We propose that the conserved gene organization is representative of the replication origin region of a primordial phage.

Analysis of the stabilization system of pSM19035-derived plasmid pBT233 in Bacillus subtilis

The low-copy-number, 9.0-kb pSM19035-derived plasmid pBT233, is stably inherited in Bacillus subtilis. The complete nucleotide (nt) sequence of pBT233 has been determined. Analysis of the nt sequence revealed nine major open reading frames (orfs). The repS, erm1 and erm2 genes have been assigned to three of these orfs, and given the gene order, repS-orf alpha-orf beta-orf gamma-orf delta-orf epsilon-orf zeta-erm2-erm1. The organization of genes of the repS-orf gamma region resembles the organization of genes in the repE-orfI region of pAM beta 1. Messenger RNA species of molecular weights corresponding to repS, orf alpha + orf beta, orf gamma, orf delta and orf epsilon + orf zeta were detected by Northern blotting. Proteins of 23.8, 81.3, 34.4, 10.7 and 32.4 kDa correspond to Orfs beta, gamma, delta, epsilon and zeta, respectively. Bands of radioactive proteins of 25, 81, 34, 10 and 32 kDa were detected using the T7 promoter-expression system. The orf beta and orf gamma encode proteins that share homology to site-specific recombinases and type-I topoisomerases, respectively. The orfs, delta, epsilon and zeta, encode proteins with unknown activity. Deletion of a 1.5-kb segment (nt 2999-4552) with coding capacity for orf beta, orf gamma and orf delta does not seem to affect plasmid maintenance. Removal of a 3.0-kb fragment (nt 4598-7689) with coding capacity for orf epsilon and orf zeta reduced plasmid segregational stability, but deletion of a 5.2-kb DNA segment (nt 2546-7826) abolished it.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of the effectors required for stable inheritance of Streptococcus pyogenes pSM19035-derived plasmids in Bacillus subtilis

The low-copy-number and broad-host-range pSM19035-derived plasmid pBT233 is stably inherited in Bacillus subtilis cells. Two distinct regions, segA and segB, enhance the segregational stability of the plasmid. Both regions function in a replicon-independent manner. The maximization of random plasmid segregation is accomplished by the recombination proficiency of the host or the presence of the pBT233 segA region. The segA region contains two open reading frames (orf) [alpha and beta]. Inactivation or deletion of orf beta results in SegA- plasmids. Better than random segregation requires an active segB region. The segB region contains two orfs (orf epsilon and orf zeta). Inactivation of either of the orfs does not lead to an increase in cell death, but orf zeta- plasmids are randomly segregated. These results suggest that pBT233 stabilization relies on a complex system involving resolution of plasmid oligomers (segA) and on the function(s) encoded by the segB region.

Sequence analysis of the left end of the Bacillus subtilis bacteriophage SPP1 genome

The left end of the genome of Bacillus subtilis bacteriophage SPP1 is represented by EcoRI DNA fragments 12 and 1 (EcoRI-12 and EcoRI-1). A number of different deletions were identified in EcoRI-1. A detailed physical and genetic map of EcoRI-1 from wild-type (wt) phage and SPP1 deletion mutants was constructed. Genes encoding essential products involved in late and early stages of phage DNA metabolism were mapped at the left and right ends of the 8.5-kb EcoRI-1, respectively. Deletions fell within the internal 5157-bp DNA segment of EcoRI-1. The nucleotide (nt) sequence of this region and of the endpoints of two deletions, delta X and delta L, were determined. The nt sequence of the junctions in SPP1 delta X and SPP1 delta L showed that, in these deletions, a segment of DNA between short directly repeated sequences of 10 and 13 bp, located 3427 and 4562 bp apart in the wt sequence, had been eliminated. In both cases, the copy of the repeated sequence was retained in the deletion mutant, consistent with the hypothesis that the deletions originated by homologous intramolecular recombination. The corresponding region in wt phage had fifteen presumptive open reading frames (orfs) and the previously identified SPP1 early promoters (PE1). The poor growth phenotype associated with the SPP1 deletion mutants was attributed to premature transcriptional read through from promoter(s) of the early region into late operon brought into close vicinity of the late genes due to the deletion event.

Potassium channel antagonists and vascular reactivity in stroke-prone spontaneously hypertensive rats

The goal of this study was to characterize differences in contractile responsiveness to several potassium channel antagonists in vascular smooth muscle from stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto normotensive rats (WKY). Helically-cut strips of carotid arteries (endothelium removed) from SHRSP and WKY were mounted in muscle baths for measurement of isometric force generation. Contractile responses to tetraethylammonium (10(-4) to 3 x 10(-2) mol/L) and barium (3 x 10(-5) mol/L), blockers of the voltage-dependent and large conductance, calcium activated potassium channels, were greater in carotid arteries from SHRSP than in those from WKY. In contrast, contractile responses to the voltage-dependent potassium channel blockers 3,4-diamino-pyridine (10(-6) to 3 x 10(-3) mol/L) and sparteine (10(-6) to 3 x 10(-2) mol/L) in arteries from SHRSP did not differ from WKY values. Carotid arteries from SHRSP and WKY did not contract to apamin (10(-9) to 10(-6) mol/L), an antagonist of the small conductance, calcium activated potassium channel. Furthermore, relaxation responses to diazoxide (3 x 10(-4) mol/L), an activator of the ATP-sensitive potassium channel, and subsequent contractions to the ATP-sensitive potassium channel blocker glyburide (10(-8) to 3 x 10(-6) mol/L) in arteries from SHRSP did not differ from WKY values. Carotid artery segments from SHRSP were more sensitive to the contractile effects of elevated potassium than those from WKY. We conclude that altered activity of the large conductance, calcium activated potassium channel may play a role in the increased responsiveness observed in arteries from SHRSP.

Extracellular calcium, contractile activity and membrane potential in tail arteries from genetically hypertensive rats

OBJECTIVE AND DESIGN

This study compares the effect of extracellular calcium on contractile responsiveness and membrane potential (E(m)) in arteries from stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto normotensive (WKY) rats.

METHODS

Isometric force and E(m) were measured in isolated tail artery strips using standard muscle bath and microelectrode techniques, respectively.

RESULTS

The resting contractile force in SHRSP and WKY arteries was not influenced by the extracellular calcium concentration. However, the rate of force development in response to norepinephrine (3 x 10(-8) mol/l) was slowed when calcium was elevated and increased when calcium was reduced. Compared with WKY rats, this stabilizing action of calcium on contractions to norepinephrine was reduced in SHRSP. In 1.6 mmol/l calcium, resting E(m) in SHRSP did not differ from that in WKY rats. Calcium-free buffer caused depolarization in SHRSP and WKY rats. Reductions in calcium below physiological levels resulted in depolarization, whereas elevations in calcium caused hyperpolarization. Regardless of the calcium concentration, E(m) values in SHRSP did not differ from those in WKY rats. Norepinephrine (3 x 10(-8) mol/l) caused a depolarization in WKY rat and SHRSP arteries, and the magnitude of this depolarization was not influenced by calcium. Endothelium removal did not alter the stabilizing effects of calcium on the membrane potential or contractile activity in WKY rats or SHRSP.

CONCLUSIONS

The reduced stabilizing effect of calcium on the contractile activity in SHRSP arteries is not due to an alteration in the general effect of the cation on the membrane potential.

Molecular analysis of the Bacillus subtilis bacteriophage SPP1 region encompassing genes 1 to 6. The products of gene 1 and gene 2 are required for pac cleavage

Packaging of Bacillus subtilis phage SPP1 DNA into viral capsids is initiated at a specific DNA site termed pac. Using an in vivo assay for pac cleavage, we show that initiation of DNA synthesis and DNA packaging are uncoupled. When the DNA products of pac cleavage were analyzed, we could detect the pac end that was destined to be packaged, but we failed to detect the other end of the cleavage reaction. SPP1 conditional lethal mutants, which map adjacent to pac, were analyzed with our assay. This revealed that the products of gene 1 and gene 2 are essential for pac cleavage. SPP1 mutants that are affected in the genes necessary for viral capsid formation (gene 41) or involved in headful cleavage (gene 6) remain proficient in pac site cleavage. Analysis of the nucleotide sequence (2.769 x 10(3) base-pairs) of the region of the genes required for pac cleavage revealed five presumptive genes. We have assigned gene 1 and gene 2 to two of these open reading frames (orf), giving the gene order gene 1-gene 2-orf 3-orf 4-orf 5. The direction of transcription of the gene 1 to orf 5 operon and the length of the mRNAs was determined. We have identified, upstream from gene 1, the major transcriptional start point (P1). Transcription originating from P1 requires a phage-encoded factor for activity. The organization of gene 1 and gene 2 of SPP1 resembles the organization of genes in the pac/cos region of different Escherichia coli double-stranded DNA phages. We propose that the conserved gene organization is representative of the packaging machinery of a primordial packaging system.

Basal body temperature and endometriosis

This investigation examined the association between pelvic endometriosis and altered basal body temperature (BBT). The study population consisted of infertile women who have been diagnosed as having endometriosis. A significant association was found between the presence of pelvic endometriosis (without previous treatment) and the appearance of a late decline in BBT during the early follicular phase of the menstrual cycle. A temperature greater than 97.8 degrees F on the first 3 days of menses is associated with pelvic endometriosis. The findings of this study support the early clinical diagnosis of endometriosis in infertile women. Basal body temperature chart analysis may be useful as a clinical adjunct when endometriosis is suspected.

Protective anti-sporozoite antibodies induced by a chemically defined synthetic vaccine

Chemically defined synthetic polymers, known as multiple antigen peptide systems (MAPs) represent an effective and novel approach for engineering peptide-based vaccines. Ten different mono and diepitope MAP models, containing different arrangements and stoichiometry of functional B and/or T helper epitopes from the circumsporozoite protein of Plasmodium berghei were used to immunize mice. High titers of antibody and protective immunity against sporozoite challenge were elicited by MAPs containing T and B epitopes arranged in tandem and in equimolar amounts. These results indicate that MAPs may serve as a basis for developing subunit vaccines to induce high levels of antibodies against sporozoites.