Frequent and strong cold-air pooling drives temperate forest composition

Cold-air pooling is an important topoclimatic process that creates temperature inversions with the coldest air at the lowest elevations. Incomplete understanding of sub-canopy spatiotemporal cold-air pooling dynamics and associated ecological impacts hinders predictions and conservation actions related to climate change and cold-dependent species and functions. To determine if and how cold-air pooling influences forest composition, we characterized the frequency, strength, and temporal dynamics of cold-air pooling in the sub-canopy at local to regional scales in New England, USA. We established a network of 48 plots along elevational transects and continuously measured sub-canopy air temperatures for 6-10 months (depending on site). We then estimated overstory and understory community temperature preferences by surveying tree composition in each plot and combining these data with known species temperature preferences. We found that cold-air pooling was frequent (19-43% seasonal occurrences) and that sites with the most frequent inversions displayed inverted forest composition patterns across slopes with more cold-adapted species, namely conifers, at low instead of high elevations. We also observed both local and regional variability in cold-air pooling dynamics, revealing that while cold-air pooling is common, it is also spatially complex. Our study, which uniquely focused on broad spatial and temporal scales, has revealed some rarely reported cold-air pooling dynamics. For instance, we discovered frequent and strong temperature inversions that occurred across seasons and in some locations were most frequent during the daytime, likely affecting forest composition. Together, our results show that cold-air pooling is a fundamental ecological process that requires integration into modeling efforts predicting future forest vegetation patterns under climate change, as well as greater consideration for conservation strategies identifying potential climate refugia for cold-adapted species.

Valuing EQ-5D-Y: the current state of play

BACKGROUND

For nearly a decade, value sets for the EQ-5D-Y were not available, reflecting challenges in valuing child HRQoL. A methodological research programme led to publication of a valuation protocol in 2020, which was rapidly taken up by local study teams. By the end of 2022, between 11 and 17 EQ-5D-Y value sets will be available, more than for any other child HRQoL measure. It is timely to review the experience of those using the protocol to identify early learnings and remaining issues where more research is needed.

METHODS

In June 2021, the EuroQol Group organised a three-day workshop, bringing together all those involved in EQ-5D-Y value set studies and related methodological research concerning EQ-5D-Y and valuation. Workshop discussions were captured by note taking and recording all sessions and online chat. A narrative summary of all sessions was produced and synthesised to identify points of agreement and aspects of methods where uncertainty remains.

RESULTS

There was broad agreement that DCE is working well as the principal valuation method. However, the most appropriate means of anchoring the latent scale values produced by DCE remains unclear. Some studies have deviated from the protocol by extending the number of states included in TTO tasks, to better support modelling of DCE and TTO. There is ongoing discussion about the relative merits of alternative variants of TTO and other methods for anchoring. Very few studies have consulted with local end-users to gauge the acceptability of methods used to value EQ-5D-Y.

CONCLUSIONS

Priority areas for research include testing alternative methods for anchoring DCE data; exploring the preferences of adolescents; and scale differences in values for EQ-5D-Y and adult EQ-5D states, and implications of such differences for the use of EQ-5D-Y values in HTA. Given the normative elements of the protocol, engaging with HTA bodies and other local users should be the first step for all future value set studies. Value sets undertaken to date are for the three-level EQ-5D-Y. However, the issues discussed in this paper are equally relevant to valuation of the five-level version of EQ-5D-Y; indeed, similar challenges are encountered valuing any measure of child HRQoL.

Transcriptional up-regulation of host-specific terpene metabolism in aphid-induced galls of Pistacia palaestina

Galling insects gain food and shelter by inducing specialized anatomical structures in their plant hosts. Such galls often accumulate plant defensive metabolites protecting the inhabiting insects from predation. We previously found that, despite a marked natural chemopolymorphism in natural populations of Pistacia palaestina, the monoterpene content in Baizongia pistaciae-induced galls is substantially higher than in leaves of their hosts. Here we show a general up-regulation of key structural genes in both the plastidial and cytosolic terpene biosynthetic pathways in galls as compared with non-colonized leaves. Novel prenyltransferases and terpene synthases were functionally expressed in Escherichia coli to reveal their biochemical function. Individual Pistacia trees exhibiting chemopolymorphism in terpene compositions displayed differential up-regulation of selected terpene synthase genes, and the metabolites generated by their gene products in vitro corresponded to the monoterpenes accumulated by each tree. Our results delineate molecular mechanisms responsible for the formation of enhanced monoterpene in galls and the observed intraspecific monoterpene chemodiversity displayed in P. palaestina. We demonstrate that gall-inhabiting aphids transcriptionally reprogram their host terpene pathways by up-regulating tree-specific genes, boosting the accumulation of plant defensive compounds for the protection of colonizing insects.

Nonconcordance of E, N, and RdRp Genes in SARS-Coronavirus-2 Nucleic Acid Amplification Test Among Patients Older than 60 Years

Introduction/Objective

During the COVID-19 pandemic, the FDA authorized emergency use of nucleic acid amplification (NAA) testing. Accurate and rapid testing identifies infected persons, especially among at-risk populations. In our institution, the InGenius platform detects three gene targets of SARS-Coronavirus-2: envelope (E), nucleocapsid (N), and RNA-dependent RNA polymerase (RdRp). Nonconcordance of these components present accuracy or precision errors or may correspond to varying expression of viral genes with disease progression.

Methods

We retrospectively analyzed the result components from 93 nasopharyngeal swabs from 50 patients older than 60 years and positive for SARS-Coronavirus-2 (SARS-CoV-2). The symptom onset date was determined by chart review.

Results

We found a significant 26% nonconcordance rate, with a predominant pattern demonstrating positive N with negative RdRp and E (χ2 = 27.25, P < 0.0005). This nonconcordant pattern was more prevalent at longer symptom durations. In 7 patients with serial testing, the transition from concordant to nonconcordant results occurred 12 days (95% CI 3.5 – 20.3 days) after symptom onset.

Conclusion

This may be caused by several mechanisms. Possibilities include decreased expression of E and RdRp over time, inhibition of expression by treatments or host immune response, or lower viral titers by clearance or migration to the lower respiratory tract. Presence of a different viral strain or systematic processing errors are less likely causes of nonconcordance. Future directions of study would determine whether a similar decline in RdRp and E detection is seen in tracheal samples or if this correlates with changes in symptom severity.

Factors underlying metastatic breast cancer patients' perceptions of symptom importance: a qualitative analysis

The symptom literature in cancer has primarily examined symptom severity, frequency and distress. Assessing cancer patients' perceptions of symptom importance-how important it is for them to see improvement in a symptom following an intervention-and factors influencing these judgments would also inform patient-centred care, but this analysis has not been undertaken. This qualitative study aimed to identify factors underlying perceptions of symptom importance among 25 symptomatic metastatic breast cancer (MBC) patients. Participants were recruited from a cancer centre in the Midwestern USA. Semi-structured interviews focused on patients' rationale for considering common symptoms (i.e., anxiety, sadness, sleep problems, pain or fatigue) to be important. Thematic analyses revealed five interrelated factors underlying MBC patients' perceptions of symptom importance: activity restriction, concentration difficulties, exacerbation of other physical symptoms, symptom-related long-term health concerns and negative impact on their relationships with others. Patients most frequently stated that a physical or psychological symptom was important because of the resulting activity restriction. Additionally, some patients considered pain to be important because it signalled potential long-term health concerns, such as worsening metastatic disease. Findings suggest that clinicians should take into account MBC patients' perceptions of symptom importance and factors underlying these judgments when making shared treatment decisions.

Formation of covalent di-tyrosine dimers in recombinant α-synuclein

Parkinson's disease is associated with fibril deposition in the diseased brain. Misfolding events of the intrinsically disordered synaptic protein α-synuclein are suggested to lead to the formation of transient oligomeric and cytotoxic species. The etiology of Parkinson's disease is further associated with mitochondrial dysfunction and formation of reactive oxygen species. Oxidative stress causes chemical modification of native α-synuclein, plausibly further influencing misfolding events. Here, we present evidence for the spontaneous formation of covalent di-tyrosine α-synuclein dimers in standard recombinant protein preparations, induced without extrinsic oxidative or nitrative agents. The dimers exhibit no secondary structure but advanced SAXS studies reveal an increased structural definition, resulting in a more hydrophobic micro-environment than the highly disordered monomer. Accordingly, monomers and dimers follow distinct fibrillation pathways.

The mono - and sesquiterpene content of aphid-induced galls on Pistacia palaestina is not a simple reflection of their composition in intact leaves

Pistacia palaestina Boiss. (Anacardiaceae), a sibling species of P. terebinthus also known as turpentine tree or terebinth tree, is common in the Levant region. The aphid Baizongia pistaciae L. manipulates the leaves of the plant to form large galls, which provide both food and protection for its developing offspring. We analyzed the levels and composition of mono-and sesquiterpenes in both leaves and galls of ten naturally growing trees. Our results show that monoterpene hydrocarbons are the main constituents of P. palaestina leaves and galls, but terpene levels and composition vary among trees. Despite this inter-tree variation, terpene levels and compositions in galls from different trees resemble each other more than the patterns displayed by leaves from the same trees. Generally, galls contain 10 to 60 fold higher total terpene amounts than leaves, especially of the monoterpenes α-pinene and limonene. Conversely, the leaves generally accumulate more sesquiterpenes, in particular E-caryophyllene, germacrene D and δ-cadinene, in comparison to galls. Our results clearly show that the terpene pattern in the galls is not a simple reflection of that of the leaves and suggest that aphids have a strong impact on the metabolism of their host plant, possibly for their own defense.

Histopathologic resolution of adult liver transplantation adenovirus hepatitis with cidofovir and intravenous immunoglobulin: a case report

Adenovirus (ADV) infections in adult solid organ transplant recipients, although rare, are associated with high mortality. There are no randomized controlled trials establishing the efficacy of specific treatment modalities. To our knowledge apparent response to treatment with combination therapy with intravenous cidofovir (CDV) and immunoglobulin (IVIG) has only been demonstrated in 2 adult renal transplant recipients in whom ADV was documented in body fluids only. We describe an adult liver transplant recipient diagnosed with ADV hepatitis based on positive immunohistochemical staining of a liver biopsy specimen, positive blood ADV DNA polymerase chain reaction (PCR), and treated with the combination of CDV and IVIG. We demonstrated both clearance of viremia and histopathologic resolution of the hepatitis despite the patient's fatal outcome. To our knowledge this is the only case documenting eradication of tissue-invasive ADV disease in any solid organ transplant recipient using CDV and IVIG. This case provides evidence to support the use of this drug combination, which has many potential toxicities that might discourage its use otherwise.

Induction of karyopherin α1 expression by indole-3-acetic acid in auxin-treated or overproducing tobacco plants

Macromolecules may transfer between the cytoplasm and the nucleus only through specific gates - the nuclear pore complexes (NPCs). Translocation of nucleic acids and large proteins requires the presence of a nuclear localization signal (NLS) within the transported molecule. This NLS is recognized by a class of soluble transport receptors termed karyopherins α and beta. We previously characterized the expression pattern of the tomato karyopherin α 1 (LeKAPα1) promoter in transformed tobacco plants. Expression of LeKAPα1 was mainly observed in growing tissues where cell division and extension is rapid. The expression pattern of LeKAPα1 resembled that of auxin-responsive genes. This led us to suggest that auxin participates in the regulation of LeKAPα1 expression. Here we characterized the correlation between auxin level and the activity of the LeKAPα1 promoter. To this end, transgenic tobacco plants carrying the GUS reporter gene under the control of the LeKAPα1 promoter were treated with various levels of exogenous auxin. We also studied transgenic plants in which we increased the endogenous levels of auxin. For this, we expressed in plants both the LeKAPα1 promoter-GUS reporter and the Agrobacterium tumefaciens iaaM gene, which increases the endogenous levels of auxin. The results indicate that the auxin indole-3-acetic acid (IAA) can induce LeKAPα1 expression. We also identified that the sites and levels of LeKAPα1 expression correlated with the endogenous pathways of polar auxin transport.

Coping styles and psychological outcomes in men with advanced cancer

e20521

Background: The psychological outcomes of men with advanced cancer may vary based upon their appraisal and response to the threat of cancer. Coping styles in other illnesses are influenced by gender and stage of disease, but little is known specifically about men with advanced cancer. Methods: We recruited 81 men with advanced cancer to complete surveys assessing coping (Mini-MAC), post-traumatic growth (PTGI), and psychological outcomes (Hospital Anxiety and Depression Scale). Psychological outcomes and coping styles were determined with means, and percentages above established cutoff points. Relationships were assessed using Pearson correlation coefficients. Results: The mean HADS anxiety and depression scores were 5.4 and 4.0, respectively. Fourteen men (17%) scored 8–10 and 8 (10%) scored ≥11 suggesting an anxiety state and disorder, respectively. Eight men (10%) had scores suggesting a depressive state and 4 (5%) a depressive disorder. Greater helplessness/hopelessness and anxious preoccupation scores were correlated with greater anxiety (r =.54, p<.0001; r =.66, p<.0001) and depression scores (r =.43, p<.0001; r=.47, p<.0001). Greater fighting spirit correlated with less anxiety (r =-.26, p=.018) and less depression (r = -.42, p < .0001) and with increased post-traumatic growth in the form of new possibilities (r = .26, p = .020), personal strength (r = .33, p = .003), and the total PTGI score (r = .23, p = .043). Greater fatalism was associated with lower total distress measured by the total HADS score (r = -.24, p = .032), and marginally so when assessed separately for anxiety (r = -.22, p = .052) and depression (r = -.21, p = .056). In addition, greater fatalism was significantly associated with greater post-traumatic growth in all five areas assessed by the PTGI subscales (.27 < r < .36; .001 p < .032). Conclusions: As expected men with advanced cancer report anxiety and depression. Coping styles were significantly associated with anxiety, depression, and post-traumatic growth.

No significant financial relationships to disclose.

Effect of coping styles on the psychological impact of discussing life expectancy for men with advanced cancer

9615

Background: Discussions of life expectancy between men and oncologists are limited, in part, because of the potential adverse effect on psychological outcomes. However, appraisal of the cancer threat may enhance coping and improve psychological outcomes for some men with advanced cancer. Methods: We recruited 81 men with advanced cancer to complete surveys including coping (Mini-MAC), post-traumatic growth (PTGI), psychological outcomes (Hospital Anxiety and Depression Scale). Men and oncologists rated extent of discussions about life expectancy. Moderation was assessed with regression interactions and follow-up within group Pearson correlations. Results: Men reported a full (33%), brief (41%), or no (26%) discussion of life expectancy. Concordance was low. Only 23 (28%) agreed with oncologists about the extent of discussion. Among the 34 oncologists who reported having a full discussion, 16 (47%) of their patients reported having a brief discussion and 8 (24%) reported no discussion. Men who reported having a full discussion had significantly lower depression scores (mean = 2.8) than those who reported a brief or no discussion (mean = 4.6; p=.018). As expected, the extent of discussion moderated some of the relationships between coping style and outcomes. Helpless-hopeless coping was associated with greater depression only among patients who reported a full or brief discussion of life expectancy (n=61, r=.56, p<.0001). Interestingly, greater fatalism was associated with greater PTGI spiritual change among men who reported no or brief discussions (n = 54, r = .39, p = .004) and greater PTGI personal strength (n = 20, r = .63, p = .003) and PTGI appreciation of life (n = 20, r = .62, p = .003) among men who reported no discussion compared to men with full and brief or full discussion, respectively. Conclusions: Most men and oncologists reported discussions of life expectancy but there was little agreement on extent. Full discussions were not associated with depression; however this effect was moderated by coping styles.

No significant financial relationships to disclose.

Relationships among patient-level factors, religious coping, use of complementary and alternative medicine, and psychological outcomes in men with advanced cancer

e20652

Background: Religious coping and complementary and alternative medicine (CAM) are two resources frequently used to manage distress associated with advanced cancer. However, the relationships among these coping strategies and psychological outcomes in men with advanced cancer are not well studied. We hypothesized that patient-level factors (e.g., demographics, personality) would predict religious coping and CAM use, which would then predict psychological outcomes. Methods: 81 men with advanced cancer were recruited from oncology clinics for this cross-sectional study. Patients completed surveys which included demographic questions, personality measures (Adult Hope Scale, Life Orientation Test-Revised), CAM use, religious coping (Brief R-COPE), and psychological outcomes (Hospital Anxiety and Depression Scale, Post-Traumatic Growth Inventory). Hierarchical regression analyses were conducted with anxiety, depression, and post-traumatic growth as the criterion variables. Results: Higher anxiety scores were predicted by more negative RC (β = 0.50, p = .002), hope-pathways (β = 0.37, p = .033), and less hope-agency (β = -0.55, p = .002). Depression was predicted by lower hope-agency (β = -0.48, p = .021) and less education (β = -0.37, p = .044). Greater post-traumatic growth was predicted by greater positive RC (β = 0.54, p = .003). CAM use did not predict any psychological outcomes. Greater positive RC was predicted by less education (β = -0.39, p = .025). More negative RC was predicted by lower optimism (β = -0.43, p = .006). CAM use was predicted by greater hope-pathways (β = 0.42, p = .046). Conclusions: Religious coping, but not CAM use, was associated with psychological outcomes. Positive RC predicted greater growth, whereas negative RC predicted greater anxiety. Psychological outcomes were related to patient-level factors including hope and education. However, the two dimensions of trait hope had opposite effects. Higher hope-agency predicted less anxiety and depression, whereas higher hope-pathways predicted greater anxiety. These relationships merit further investigation.

No significant financial relationships to disclose.

Impact of tazobactam pharmacokinetics on the antimicrobial effect of piperacillin–tazobactam combinations

Pharmacokinetic-pharmacodynamic (PK-PD) modelling was used to study the impact of the pharmacokinetics of tazobactam on the antimicrobial effect of piperacillin-tazobactam combinations. An in vitro experiment using a novel dilution system was performed to compare the effects of two conditions of the combination therapy against Escherichia coli ATCC35218, a beta-lactamase producing bacterium. Both conditions simulated the same initial concentrations of piperacillin and tazobactam, but different elimination half-lives for tazobactam. The killing and regrowth kinetics of E. coli clearly indicated that there is a difference in the antimicrobial effects when there is a difference in the pharmacokinetics of tazobactam in the combination therapy. The results show that for equal piperacillin exposure, different tazobactam half-lives will have a significant effect on antimicrobial outcome.

Interactive role of infection, inflammation and traditional risk factors in atherosclerosis and coronary artery disease

Although first suggested at the turn of the 20th century, there is a renewed interest in the infectious theory of atherosclerosis. Studies done in many laboratories around the world over the past several years have shown an association between markers of inflammation and coronary atherosclerosis with an exacerbation of the inflammatory process during acute myocardial ischemia, particularly in the early stages of reperfusion. It is also being recognized that the traditional risk factors, such as smoking, dyslipidemia, hypertension and diabetes mellitus, do not explain the presence of coronary atherosclerosis in a large proportion of patients. We believe that in certain genetically susceptible people, infection with very common organisms, such as Chlamydia pneumoniae or cytomegalovirus, may lead to a localized infection and a chronic inflammatory reaction. Persistence of infection may relate to the degree of inflammation and severity of atherosclerosis. Early trials with appropriate antibiotic agents in some patients with a recent history of acute myocardial infarction have led to very salutary results. If patients with an infectious basis of atherosclerosis can be identified, a therapy directed at eradication of the offending organism may be appropriate.

Pharmacokinetic-pharmacodynamic modelling of the in vitro antiinfective effect of piperacillin-tazobactam combinations

PURPOSE

The aim of the study was to investigate the in vitro antiinfective effect of piperacillin-tazobactam (PIP-TZB) combinations on Escherichia coli in simulations of free concentration time profiles of both drugs, similar to those obtained in human tissue after i.v. bolus administrations.

METHODS

An in vitro dilution model was used to expose E. coli ATCC 35218 (beta-lactamase producer) to various piperacillin-tazobactam concentration profiles obtained after i.v. bolus multiple dose, using different dose ratio combinations (1:4, 1:8, 1:16) and dosing regimens, ranging from once-a-day to 4 times a day. The antimicrobial effect was evaluated by determination of the number of bacteria over time. The concentration of PIP in the model was determined by HPLC.

RESULTS

A modified Emax model was used to describe the pharmacodynamic effect. The model was linked with the piperacillin concentrations determined experimentally to provide a pharmacokinetic-pharmacodynamic (PK-PD) model. The EC50 for piperacillin alone averaged 5.66 +/- 0.29 micrograms/ml. The EC50 for all doses of piperacillin combined with 0.5 g of tazobactam were dose-dependent and averaged 1.70 +/- 0.56, 3.95 +/- 1.02, and 6.14 +/- 1.24 micrograms/ml for PIP 2, 4, and 8 g, respectively. By increasing the dose of TZB in combination with a fixed dose of PIP, a decreased EC50 was observed.

CONCLUSIONS

The PK-PD model allowed a detailed evaluation of the dosing regimens investigated. The results suggested that for these combinations, 3 times a day administration is as effective as 4 times a day. Pharmacodynamic activity of the combinations can be prolonged by sufficiently high inhibitor concentrations.

A cDNA encoding the calcitonin gene-related peptide type 1 receptor

Calcitonin gene-related peptide (CGRP) is a neuropeptide with diverse biological effects including potent vasodilator activity. We report here the cloning of a complementary DNA (cDNA) encoding a human CGRP1 receptor, which shares significant peptide sequence homology with the human calcitonin receptor, a member of the G-protein-coupled receptor superfamily. Northern blot analysis revealed that the messenger RNA for this receptor is predominantly expressed in the lung and heart. In situ studies showed specific localization of the receptor mRNA to alveolar cells in the lung and to cardiac myocytes in the heart. Stable expression of the cDNA in human embryonic kidney 293 (HEK 293) cells produced specific, high affinity binding sites for CGRP that displayed pharmacological and functional properties very similar to native human CGRP1 receptor. Exposure of these cells to CGRP resulted in a 60-fold increase in cAMP production, which was inhibited in a competitive manner by the CGRP1 receptor antagonist, CGRP-(8-37).

Multicenter in vitro comparative study of fluoroquinolones after four years of widespread clinical use

In vitro activities of ciprofloxacin, fleroxacin, lomefloxacin, ofloxacin, and seven other oral antimicrobials including amoxicillin-clavulanic acid (A/C), oxacillin, cefaclor, cefixime, cefuroxime, erythromycin, and trimethoprim-sulfamethoxazole (T/S) were evaluated against 1708 fresh bacterial isolates from four hospital laboratories approximately 4 years after the introduction of ciprofloxacin. T/S and ofloxacin had the lowest MIC90s and greatest percentage of susceptible strains overall, followed by the other three quinolones. Quinolones were the most active drugs tested against Gram-negative bacteria, with little variation in the activity among the four compounds against most species. Quinolone resistance was detected to some degree in the majority of Gram-negative species tested, with Pseudomonas, Acinetobacter, Xanthomonas, and Providencia demonstrating the highest percentage of resistant strains. Ofloxacin and ciprofloxacin were relatively more active against Gram-positive bacteria than were fleroxacin and lomefloxacin, but T/S and A/C had more susceptible strains than any of the quinolones. Oxacillin-resistant staphylococci, enterococci, and streptococci exhibited the least quinolone susceptibility. This study showed that while resistance is developing among several previously susceptible bacterial species, quinolones remain important alternatives for the oral treatment of many types of infections. Actions to prevent or limit resistance will be important to maintain the viability of the quinolones as therapeutic agents in both hospital and community environments.

Buffered charcoal-yeast extract medium for the isolation of brucellae

A patient with chronic osteomyelitis caused by Brucella abortus had negative agglutination titers. Because of a superimposed staphylococcal infection that resulted in the overgrowth of this organism on nonselective media, brucellae were isolated only on a selective buffered charcoal-yeast extract (BCYE) agar. Sixteen strains of various Brucella species were inoculated on BCYE agar; selective BCYE agar with polymyxin, anisomycin, and cefamandole; and brucella blood agar. The growth and recovery rates on the three media tested were comparable for 14 strains. BCYE agar with polymyxin, anisomycin, and cefamandole may be useful as a selective medium for the isolation of brucellae.

Recurrent varicella-zoster infection after acyclovir therapy in immunocompromised patients

Varicella-zoster virus (VZV) infection is a late complication of bone marrow transplantation in almost half of the long-term survivors. We have reported the clinical relapse of VZV infection in two marrow transplant recipients treated with standard regimens of acyclovir, a new antiviral agent with activity against VZV. Since most VZV infections occur after discharge from a transplant center, primary care physicians must be alert to the possibility of relapse of VZV infection after acyclovir therapy.

Identification and characterization of the alc gene product of bacteriophage T4

Bacteriophage T4 infection rapidly and almost completely inhibits transcription of host and other phage DNAs. Two processes have been implicated to date in this inhibition: (1) ADP ribosylation of the alpha subunits of the RNA polymerase, involving gpalt (which is injected with the phage DNA) and, later, gpmod; and (2) the action of the T4 alc/unf gene product, synthesized immediately after infection. The latter unfolds the host genome and also blocks transcription of cytosine-containing DNA. Here, we describe the identification on two-dimensional polyacrylamide gels of gpalc/unf, the more precise mapping of the gene and the identification and analysis of the appropriate DNA sequence from an Unf+ alc mutant.