MIPS: a database for genomes and protein sequences

The Munich Information Center for Protein Sequences (MIPS-GSF, Neuherberg, Germany) continues to provide genome-related information in a systematic way. MIPS supports both national and European sequencing and functional analysis projects, develops and maintains automatically generated and manually annotated genome-specific databases, develops systematic classification schemes for the functional annotation of protein sequences, and provides tools for the comprehensive analysis of protein sequences. This report updates the information on the yeast genome (CYGD), the Neurospora crassa genome (MNCDB), the databases for the comprehensive set of genomes (PEDANT genomes), the database of annotated human EST clusters (HIB), the database of complete cDNAs from the DHGP (German Human Genome Project), as well as the project specific databases for the GABI (Genome Analysis in Plants) and HNB (Helmholtz-Netzwerk Bioinformatik) networks. The Arabidospsis thaliana database (MATDB), the database of mitochondrial proteins (MITOP) and our contribution to the PIR International Protein Sequence Database have been described elsewhere [Schoof et al. (2002) Nucleic Acids Res., 30, 91-93; Scharfe et al. (2000) Nucleic Acids Res., 28, 155-158; Barker et al. (2001) Nucleic Acids Res., 29, 29-32]. All databases described, the protein analysis tools provided and the detailed descriptions of our projects can be accessed through the MIPS World Wide Web server (http://mips.gsf.de).

[FK 506 ointment 0.1 % - A new therapeutic option for atopic blepharitis. Clinical trial with 14 patients]

BACKGROUND

Severe atopic blepharitis is difficult to treat, as topical steroids offer only a limited therapeutic benefit with increasing side effects by time. Topical FK 506 was found to be efficient and safe for treatment of atopic dermatitis in dermatologic studies. The use of topical FK 506 in atopic blepharitis has not been reported so far.

PATIENTS AND METHODS

Fourteen patients with severe atopic blepharitis were treated with topical FK 506 0.1 %. The ointment was applied twice daily on the eye lids. Ophthalmologic examinations were scheduled at two weeks, two months and five months after onset of treatment. A score was defined for the skin of the lid (edema, erythema, lichenification, oozing, excoriation and crusting) and for the eye lid margin (erythema, thickening, crusting) respectively. Every patient graded pruritus on a visual analogue scale.

RESULTS

The mean skin score prior to treatment was 25.6 +/- 5.8, after two weeks 7.9 +/- 4.8 (p < 0.001), after two months 5.8 +/- 5.0 (p < 0.001) and after five months 5.3 +/- 5.3 (p < 0.001). The mean score for the eye lid margin prior to treatment was 12.3 +/- 4.0, after two weeks 4.6 +/- 2.7 (p < 0.001), after two months 3.8 +/- 2.4 (p < 0.001) and after five months 4.3 +/- 2.6 (p < 0.001). The mean score for pruritus prior to treatment was 8.1 +/- 1.3, after two weeks 2.0 +/- 1.4 (p < 0.001), after two months 1.3 +/- 0.8 (p < 0.001) and after five months 0.8 +/- 0.7 (p < 0.001). All patients assessed the overall situation under therapy as markedly improved.

CONCLUSIONS

Topical FK 506 0.1 % ointment turns out to be an excellent therapeutic option for treatment of severe atopic blepharitis. Long-term efficacy and safety have to be evaluated in long-term follow-up studies.

Short-term "preconditioning" with inhaled nitric oxide protects rabbit lungs against ischemia-reperfusion injury

BACKGROUND

Pulmonary edema, owing to an impairment of microvascular barrier function, is an important feature in lung ischemia/reperfusion (IR) injury. Inhalation of nitric oxide (NO) during the period of reperfusion has previously been shown to reduce this leakage response.

METHODS

We investigated the impact of short-term (30 min) low-dose (10 ppm) pre-ischemic NO inhalation on IR injury in buffer-perfused rabbit lungs, subsequently undergoing 210 min of warm, anoxic-ventilated ischemia.

RESULTS

Far-reaching suppression of the leakage response, reflected by manifold increased capillary filtration coefficients and edema formation, was noted in lungs with pre-ischemic NO administration, corresponding to the beneficial effect of NO inhalation during reperfusion. The effect of NO pre-exposure was not related to vasodilation, because microvascular pressures were unchanged, and was mimicked by pre-ischemic intravascular administration of sodium nitroprusside with subsequent washout of this agent. NO inhalation during reperfusion, but not pre-ischemic, short-term NO administration, provoked a manifold increase in the accumulation of guanosine 3',5'-cyclic monophosphate (cGMP) in the perfusate. The cGMP-analogue, 8-Br-cGMP, mimicked the anti-edematous effect of NO when present during reperfusion, but pre-ischemic, short-term administration of 8-Br-cGMP provided only limited protection. The guanylate cyclase-inhibitor, 1H-[1, 2, 4]-Oxadiazolo-[4,3-a]-quinoxalin-1-one (ODQ), largely antagonized the beneficial effects of NO inhalation during reperfusion but had only minor influence on the effect of NO pre-exposure.

CONCLUSIONS

"Preconditioning" of the lung vasculature with short-term NO administration maintains endothelial integrity in a subsequent ischemia/reperfusion maneuver, with nonvasodilatory and non-cGMP-related mechanisms suggested to be largely responsible. This finding may offer interesting perspectives for donor management in clinical lung transplantation.

Two strategies to increase adherence to HIV antiretroviral medication: life-steps and medication monitoring

Advances in the medical treatment of HIV have made it clear that adherence to highly active antiretroviral treatment is a crucial feature for treatment success. The present paper had two goals: (1) to examine psychosocial predictors of adherence in persons receiving HIV antiretroviral therapy; (2) to compared two minimal-treatment interventions to increase HIV medication adherence in a subset of persons who self-reported less than perfect adherence. One of the interventions, Life-Steps, is a single-session intervention utilizing cognitive-behavioral, motivational interviewing, and problem-solving techniques. The other intervention, self-monitoring, utilizes a pill-diary and an adherence questionnaire alone. Significant correlates of adherence included depression, social support, adherence self-efficacy, and punishment beliefs about HIV. Depression was a significant unique predictor of adherence over and above the other variables. Both interventions yielded improvement in adherence from baseline, and the Life-Steps intervention showed faster improvements in adherence for persons with extant adherence problems.

Investigation of the oxygen isotopic composition in oxidic uranium compounds as a new property in nuclear forensic science

The analysis of seized nuclear material aims at identifying the origin of the material. Determination of the n(18O)/n(16O) ratio for the uranium oxide adds another characteristic property to the pattern which enables location of the production area of the material. A method has been developed for n(18O)/n(16O) ratio measurement which uses thermal ionization mass spectrometric (TIMS) analysis of the 238UO+ species. It has been shown that uranium oxides of different geographic origin have significantly different n(18O)/n(16O) ratios, whereas different samples of the same origin have constant oxygen isotopes ratios.

Influence of injection drug use behavior on reported antiretroviral therapy use among women in the HIV Epidemiology Research study: on-site versus referral care

BACKGROUND

HIV-infected injection drug users consistently report poor antiretroviral therapy use and little contact with health care providers. It has been suggested that the clinical setting where patients are seen affects the use of highly active antiretroviral therapy.

OBJECTIVES

The purpose of this study was to determine whether ease of access to medical care affects self-report of taking antiretroviral therapy, particularly among female injection drug users.

DESIGN

The study is a cross-sectional analysis from a prospective cohort study of HIV-infected women.

SETTING

Women were enrolled at four sites in the United States: Detroit, Michigan, and Providence, Rhode Island, where on-site HIV care and treatment were offered, and Baltimore, Maryland, and the Bronx, New York, where all participants were referred elsewhere for HIV care and treatment.

PATIENTS

Patients were HIV-infected women with no AIDS diagnosis or women who were at risk for HIV infection either through self-reported injection drug use since 1985 or through sexual contact.

MEASUREMENTS

The study measured self-reported use of antiretroviral therapy (ART) alone or combined with Pneumocystis carinii (PCP) prophylaxis in the previous 6 months.

RESULTS

In multivariate analysis including type of study site (on-site compared with referral care) and injection drug use, any self-reported ART use associated with low CD4 cell count category, older age, and race. However, at on-site care centers, women were equally likely to report ART use regardless of current, former, or no injection drug use, whereas at referral sites only women identified as sexual contacts were more likely to report any ART use, independent of all other variables.

CONCLUSIONS

Easy access to medical care has an important impact on HIV-infected women receiving ART, particularly those who are active injection drug users.

Endogenous nitric oxide synthesis and vascular leakage in ischemic-reperfused rabbit lungs

Pulmonary edema formation resulting from loss of capillary barrier properties is a prominent finding in lung ischemia/reperfusion (I/R) injury. The role of endogenous nitric oxide (NO) in this process is unresolved. We exposed buffer-perfused rabbit lungs to warm I/R and measured air space NO liberation and intravascular accumulation of NO degradation products. In lungs undergoing 210 min of ischemia with normoxic ventilation, with maintenance of positive intravascular pressure to avoid vascular collapse, NO synthesis was moderately reduced during ischemia but was fully restored upon reperfusion, and a moderate leakage response occurred during reperfusion. Pretreatment with the NO synthase inhibitor N(G)-monomethyl-L-arginine (L-NMMA) suppressed NO synthesis but did not affect the leakage. During ischemia with anoxic ventilation, NO synthesis was fully abrogated, but again promptly reappeared upon reperfusion and entrance of oxygen into the system. It was with this protocol that the most severe vascular leakage was encountered, which was markedly reduced in the presence of L-NMMA or superoxide dismutase. We conclude that endogenous NO does not play a major role in the induction or mitigation of I/R injury under conditions of normoxic ischemia, but that return of endogenous NO synthesis upon reperfusion after anoxic ischemia contributes substantially to the triggering of vascular leakage, possibly via interaction with superoxide.

Conservation of microstructure between a sequenced region of the genome of rice and multiple segments of the genome of Arabidopsis thaliana

The nucleotide sequence was determined for a 340-kb segment of rice chromosome 2, revealing 56 putative protein-coding genes. This represents a density of one gene per 6.1 kb, which is higher than was reported for a previously sequenced segment of the rice genome. Sixteen of the putative genes were supported by matches to ESTs. The predicted products of 29 of the putative genes showed similarity to known proteins, and a further 17 genes showed similarity only to predicted or hypothetical proteins identified in genome sequence data. The region contains a few transposable elements: one retrotransposon, and one transposon. The segment of the rice genome studied had previously been identified as representing a part of rice chromosome 2 that may be homologous to a segment of Arabidopsis chromosome 4. We confirmed the conservation of gene content and order between the two genome segments. In addition, we identified a further four segments of the Arabidopsis genome that contain conserved gene content and order. In total, 22 of the 56 genes identified in the rice genome segment were represented in this set of Arabidopsis genome segments, with at least five genes present, in conserved order, in each segment. These data are consistent with the hypothesis that the Arabidopsis genome has undergone multiple duplication events. Our results demonstrate that conservation of the genome microstructure can be identified even between monocot and dicot species. However, the frequent occurrence of duplication, and subsequent microstructure divergence, within plant genomes may necessitate the integration of subsets of genes present in multiple redundant segments to deduce evolutionary relationships and identify orthologous genes.

The evolution of the Fenway Community Health model

Fenway Community Health was founded by community activists in 1971 in the Fenway neighborhood of Boston, Mass, and within a decade had rapidly expanded its medical services for gay men in response to the AIDS epidemic. Increased expertise and cultural competence in lesbian, gay, bisexual, and transgender (LGBT) care led to expansion of medical services to address broader community concerns, ranging from substance use to parenting issues to domestic and homophobic violence, as well as specialized programs for lesbians, bisexuals, and transgendered individuals. Fenway began as a grassroots neighborhood clinic. In 1975, the center recorded 5000 patient care visits; in 2000, Fenway's clinical departments recorded 50,850 visits by 8361 individuals, including more than 1100 individuals receiving HIV-associated care. The center now has more than 170 staff people responsible for clinical programs, community education, research, administration, planning, and development. Over the past few years, Fenway's annual budget has exceeded $10 million. Fenway has established standards for improved cultural competence about LGBT health issues for other health providers and has developed programs to educate the general community about specific LGBT health concerns. This health center may provide a model of comprehensive LGBT health services that have a local impact.

Physicochemical analysis of purified diphtheria toxoids: is toxoided then purified the same as purified then toxoided?

Diphtheria toxin can be converted into a highly immunogenic and irreversibly detoxified vaccine either using the conventional process in which the crude toxin is formalinised and subsequently purified (DTxd(conv)) or by detoxification of the highly purified toxin (DTxd(new)). In this study, both DTxd(new) and DTxd(conv) were evaluated by use of physico-chemical methods. For some methods, results were also compared to those obtained for cross-reacting material (CRM197), which is a non-toxic mutant of diphtheria toxin. DTxd(new) was assayed to have a specific purity of at least 2300 LF/mg protein N, thereby exceeding Pharm. Eur. requirements by up to 35%. Superior purity of DTxd(new) could also be demonstrated by size exclusion HPLC experiments and by amino acid composition studies. Far-UV circular dichroism spectroscopy revealed that the secondary structure of DTxd(new) almost resembled that of CRM197, suggesting only minor molecular changes during detoxification. This study worked out differences between purified diphtheria toxoids. Physico-chemical means revealed the advantages of DTxd(new) being the purer and more defined product, thus making it highly efficient for its use as a vaccine carrier as well as a component of vaccine combinations.

Safety and immunogenicity of a canarypox-vectored human immunodeficiency virus Type 1 vaccine with or without gp120: a phase 2 study in higher- and lower-risk volunteers

Live attenuated viral vectors that express human immunodeficiency virus (HIV) antigens are being developed as potential vaccines to prevent HIV infection. The first phase 2 trial with a canarypox vector (vCP205, which expresses gp120, p55, and protease) was conducted in 435 volunteers with and without gp120 boosting, to expand the safety database and to compare the immunogenicity of the vector in volunteers who were at higher risk with that in volunteers at lower risk for HIV infection. Neutralizing antibodies to the MN strain were stimulated in 94% of volunteers given vCP205 plus gp120 and in 56% of volunteers given vCP205 alone. CD8(+) cytotoxic T lymphocyte cells developed at some time point in 33% of volunteers given vCP205, with or without gp120. Phase 3 field trials with these or similar vaccines are needed, to determine whether efficacy in preventing HIV infection or in slowing disease progression among vaccinees who become infected is associated with the level and types of immune responses that were induced by the vaccines in this study.

Sequence and analysis of the Arabidopsis genome

The comprehensive analysis of the genome sequence of the plant Arabidopsis thaliana has been completed recently. The genome sequence and associated analyses provide the foundations for rapid progress in many fields of plant research, such as the exploitation of genetic variation in Arabidopsis ecotypes, the assessment of the transcriptome and proteome, and the association of genome changes at the sequence level with evolutionary processes. Nevertheless, genome sequencing and analysis are only the first steps towards a new plant biology. Much remains to be done to refine the analysis of encoded genes, to define the functions of encoded proteins systematically, and to establish new generations of databases to capture and relate diverse data sets generated in widely distributed laboratories.

[Highly active antiviral and immunosuppressive combination therapy with acyclovir and mycophenolate mofetil following keratoplasty in patients with herpetic eye disease]

BACKGROUND

Herpes simplex virus (HSV) infection is the most common cause of corneal blindness in developed countries. Penetrating keratoplasty is the only therapeutic option for visual rehabilitation in patients with severely scarred corneas. Recurrence of the underlying disease and allograft rejection (AR) are the common causes of graft failure. Systemic immuno-suppression with cyclosporin A is contraindicated due to the risk of HSV recurrence. The potent immunosuppressive properties of mycophenolate mofetil (MMF) have already been shown clinically. By reducing the intracellular guanosid-pool MMF inhibits the proliferation of lymphocytes. As these quanosin-nucleosides also act as competing substrates to acyclovir at the viral DNA-polymerase, a synergistic effect of MMF and acyclovir might be expected. The aim of this study was to evalute the efficacy and safety of a double-drug regimen with MMF and acyclovir in the prevention of acute allograft rejection and HSV recurrence following corneal transplantation.

METHODS

Patients following penetrating keratoplasty due to herpetic eye disease have been treated with MMF 1 g twice dialy and acyclovir 5 x 200 mg/day for one year. Primary efficacy variables have been the number of acute AR and recurrence of herpetic disease per patient and time. The number of adverse events has been documented for safety analysis.

RESULTS

Fifteen patients have been enrolled. The average follow up period was 9.1 (+/- 5.2) months. No graft opacifications have been seen. With two AR and no recurrence of herpetic disease the efficacy ofthis therapeutic regimen was supperior compared with historical control groups.

CONCLUSION

In this first study on the efficacy and safety of a double drum regimen with acyclovir and MMF for the control of acute corneal AR and HSV-recurrenct following keratoplasty in patients with herpetic eye disease, the combination therapy has been shown to be a safe and highly efficient protocol for graft protection.

The synergistic relationship between a level I trauma center and a regional pediatric trauma center

A regional pediatric trauma center and a level I trauma center with pediatric commitment in the same city developed a synergistic relationship addressing all aspects of care for pediatric trauma patients. Although it is unlikely that this model could be used in its entirety by all similar institutions, the principles may prove helpful in creating guidelines and relationships. Categorization, optimal use of resources, timely transportation of seriously injured children to the appropriate facility, and maintaining urgent care capabilities of each institution to care for seriously injured children are imperative. The combined effort resulted in our level I trauma center being verified by the American College of Surgeons and designated by our state Health Department as meeting all the criteria for pediatric trauma care. This experience should encourage every pediatric trauma center located in a children's hospital to become a regional pediatric trauma center. The real benefit from the relationship is that injured children receive optimal care at both institutions.

The evolution of Candida species and fluconazole susceptibility among oral and vaginal isolates recovered from human immunodeficiency virus (HIV)-seropositive and at-risk HIV-seronegative women

Antifungal agents can effectively treat mucosal candidiasis; however, their use can lead to colonization with less susceptible species and to resistance among normally susceptible strains. Oral and vaginal Candida isolates obtained at 3 points over 2 years from human immunodeficiency virus (HIV)-seropositive and at-risk HIV-seronegative women were identified by species and were evaluated for in vitro fluconazole susceptibility. Prevalence of non-C. albicans strains increased over time, and these strains were more likely among women reporting current antifungal use. Among C. albicans isolates, resistance was rare, with no evidence for progressive reduction in susceptibility over time. Among non-C. albicans isolates, reduced susceptibility occurred frequently and increased with time. HIV-seropositive women were more likely to have non-C. albicans isolates with reduced susceptibility as were women reporting current antifungal use. This evolution and section of mucosa-colonizing Candida species with reduced susceptibility could play a critical early role in the development of antifungal resistance among C. albicans isolates responsible for refractory candidiasis.

Biosynthesis of constitutive nitric oxide synthase-derived nitric oxide attenuates coronary vasoconstriction and myocardial depression in a model of septic heart failure induced by Staphylococcus aureus alpha-toxin

OBJECTIVE

Myocardial depression, which frequently occurs in the course of septic shock, has been attributed to the cardiodepressant properties of nitric oxide (NO) generated by either the inducible NO synthase (iNOS) or the constitutive isoform (cNOS). We have previously demonstrated that alpha-toxin from Staphylococcus aureus induces thromboxane-mediated vasoconstriction accompanied by severe cardiodepression in isolated rat hearts. In the present study, we investigated the role of NO in the alpha-toxin-induced vascular and contractile abnormalities.

DESIGN

Prospective, experimental study.

SETTING

Research laboratory at a university hospital.

SUBJECTS

Isolated hearts from male Wistar rats.

INTERVENTIONS

Isolated hearts were perfused with purified staphylococcal alpha-toxin for 60 mins.

MEASUREMENTS AND MAIN RESULTS

At a concentration of 0.25 and 0.5 microg/mL, alpha-toxin induced a rise in coronary perfusion pressure, depressed myocardial contractility, and caused edema formation. Simultaneously, a time- and dose-dependent rapid release of NO into the perfusate was noted as quantified by a chemiluminescence technique. L-NMMA, a nonselective inhibitor of NOS, but not PBITU, an iNOS-selective inhibitor, blocked NO synthesis, markedly increased the rise in coronary perfusion pressure and the loss in contractility, and enhanced edema formation in response to alpha-toxin. In contrast, zaprinast, a selective inhibitor of phosphodiesterase type V that is used for stabilization of cyclic guanosine monophosphate, attenuated the toxin-induced coronary vasoconstrictor response and the myocardial depression. L-arginine, the substrate of NOS, had similar, yet less potent, effects as zaprinast and slightly increased the release of NO caused by alpha-toxin. Immunohistochemical analysis of the myocardium at the end of the perfusion period demonstrated a positive staining for cNOS but not for iNOS. In addition, no up-regulation of iNOS mRNA was detected in the tissue of toxin-exposed hearts.

CONCLUSIONS

Staphylococcal alpha-toxin provokes NO biosynthesis via activation of cNOS in rat hearts. NO partly antagonizes the deleterious effects of this pathogenicity factor on coronary vasoregulation and myocardial performance.

Early human immunodeficiency virus (HIV) infection in the HIV Network for Prevention Trials Vaccine Preparedness Cohort: risk behaviors, symptoms, and early plasma and genital tract virus load

Risk behaviors, symptoms, and virologic characteristics were studied among 103 human immunodeficiency virus (HIV) seroconverters in vaccine preparedness cohorts during 1995-1998. Overall, 83% of subjects were men who had sex with men; most reported multiple risk episodes and symptoms (84%, > or =1 symptom) during seroconversion. Acute HIV was diagnosed in only 8 of 50 who sought medical care. Median initial pretreatment plasma virus load was 25,800 copies/mL (range, undetectable-262,000 copies/mL) a mean of 4 months after seroconversion, and 9.7% had nucleoside-associated mutations; none had multidrug resistance. Semen virus load was more variable, 1.3 log(10) lower and modestly correlated (r=.28; 95% confidence interval, 0.16-0.42) with plasma among untreated men. When the plasma RNA level was <5000 copies/mL, 32% of untreated men, 13% on nucleoside regimens, and 7% on protease inhibitor-containing regimens had detectable seminal RNA. Acute HIV was seldom diagnosed, representing missed opportunities for early treatment and prevention. Most subjects had several relatively stable virus loads before initiation of antiretrovirals, indicating feasibility of assessing HIV vaccines on virus set point in efficacy trials.

Analytical methods for thorium determination: a journey from conventional methods to novel applications

Thorium may be determined using a variety of analytical methods. These may be based on chemical or physical principles or may make use of the radioactive decay of the individual thorium isotopes. The method to be used for a certain analytical purpose is selected as a function of the matrix of the sample and of the concentration of thorium. The present paper describes different methodologies, their range of application and discusses selected results. The methods described cover a concentration range of more than twelve orders of magnitude, i.e. from concentrated solutions to micrometre-sized particles. Emphasis is given to active radiometric techniques, chemical and instrumental analysis.

Functionally inert HIV-specific cytotoxic T lymphocytes do not play a major role in chronically infected adults and children

The highly sensitive quantitation of virus-specific CD8(+) T cells using major histocompatibility complex-peptide tetramer assays has revealed higher levels of cytotoxic T lymphocytes (CTLs) in acute and chronic virus infections than were recognized previously. However, studies in lymphocytic choriomeningitis virus infection have shown that tetramer assays may include measurement of a substantial number of tetramer-binding cells that are functionally inert. Such phenotypically silent CTLs, which lack cytolytic function and do not produce interferon (IFN)-gamma, have been hypothesized to explain the persistence of virus in the face of a quantitatively large immune response, particularly when CD4 help is impaired. In this study, we examined the role of functionally inert CTLs in chronic HIV infection. Subjects studied included children and adults (n = 42) whose viral loads ranged from <50 to >100,000 RNA copies/ml plasma. Tetramer assays were compared with three functional assays: enzyme-linked immunospot (Elispot), intracellular cytokine staining, and precursor frequency (limiting dilution assay [LDA]) cytotoxicity assays. Strong positive associations were observed between cell numbers derived by the Elispot and the tetramer assay (r = 0.90). An even stronger association between tetramer-derived numbers and intracellular cytokine staining for IFN-gamma was present (r = 0.97). The majority (median 76%) of tetramer-binding cells were consistently detectable via intracellular IFN-gamma cytokine staining. Furthermore, modifications to the LDA, using a low input cell number into each well, enabled LDAs to reach equivalence with the other methods of CTL enumeration. These data together show that functionally inert CTLs do not play a significant role in chronic pediatric or adult HIV infection.

Sequence and analysis of chromosome 5 of the plant Arabidopsis thaliana

The genome of the model plant Arabidopsis thaliana has been sequenced by an international collaboration, The Arabidopsis Genome Initiative. Here we report the complete sequence of chromosome 5. This chromosome is 26 megabases long; it is the second largest Arabidopsis chromosome and represents 21% of the sequenced regions of the genome. The sequence of chromosomes 2 and 4 have been reported previously and that of chromosomes 1 and 3, together with an analysis of the complete genome sequence, are reported in this issue. Analysis of the sequence of chromosome 5 yields further insights into centromere structure and the sequence determinants of heterochromatin condensation. The 5,874 genes encoded on chromosome 5 reveal several new functions in plants, and the patterns of gene organization provide insights into the mechanisms and extent of genome evolution in plants.