An electrostatic backpack sprayer: potential for mosquito control

A Southwest Electrostatic Sprayers, Inc., nozzle was configured to a Hudson PortaPak backpack. A test was run to compare deposition of BVA no. 13 oil by the electrostatic nozzle to a standard nonelectrostatic nozzle as collected by Teflon slides. Results indicate that 100% greater deposition occurred with the electrostatic nozzle.

Trends in motor-vehicle related air pollutants in central London

Results of intermittent monitoring of six aromatic hydrocarbons (benzene, toluene, ethyl-benzene, m-xylene, p-xylene and o-xylene), carbon monoxide and oxides of nitrogen over a thirteen year period at a site in central London (Exhibition Road) are presented. Four monitoring regimes were undertaken; namely, 1979, 1982/83, 1986/87 and 1991/92. The summertime daytime mean ambient concentrations of the measured parameters at this site are presented. The reported concentrations show a reduction from 1979 to 1992 by approximately a factor of two, despite national increases in motor fuel consumption and the volume of traffic. Relevant European Community legislation covering emissions from motor-vehicles are outlined and comparisons are made with emissions from motor vehicles predicted from the UK national inventory. The importance of the frequency of measurements was also noted.

The role of vascular endothelial growth factor in a murine chronic granulomatous tissue air pouch model of angiogenesis

Chronic granulomatous inflammation may be considered an angiogenic-dependent process. Recently it has been demonstrated that vascular endothelial growth factor (VEGF) or vascular permeability factor is essential for tumour angiogenesis. Its role in inflammation-mediated angiogenesis has yet to be determined. In this study, the murine chronic granulomatous air pouch model was used to investigate the role of VEGF in angiogenesis. Animals were treated twice weekly with 10 micrograms per animal of neutralizing antibody to rh VEGF and the vascularity and granuloma dry weight were assessed after 7 days. This resulted in significant suppression of both angiogenesis and granuloma dry weight. Western blot analysis demonstrated the presence of VEGF; the levels of protein paralleled the angiogenic response. These results demonstrate for the first time that VEGF may be an important regulator of angiogenesis in inflammation.

Geographic and temporal patterns of recurrent intentional injury in south-central Los Angeles

To better understand geographic and temporal patterns of recurrent intentional injury, 285 consecutive trauma patients were evaluated prospectively. Fifteen were excluded because of immediate death or severe brain injury. The remaining 270 patients were interviewed. Of these, 59 (22%) had been treated in a hospital for a total of 75 previous episodes of intentional trauma (mean: 1.3 episodes/patient). In 66 of the 75 episodes, the patient recalled where treatment had been received (88%). Twenty-eight (42%) of the 66 episodes had been treated at King/Drew Medical Center (KDMC), 36 (55%) had been treated at a hospital within a 3-mile radius of KDMC, 48 (73%) within an 8-mile radius, and 63 (95%) within a 10-mile radius. Sixty-five percent of the episodes occurred 5 years or less prior to the current injury (range: 11 days to 30 years; mean: 4.9 years). Patients currently admitted for intentional injury were more likely to have had intentional injury previously than those with unintentional injury (27% versus 12%). Based on these findings, we conclude that intentional trauma patients in our community remain in a defined geographic region and that there is a definable high-risk period for recurrent intentional injury. These conclusions should enhance the development of a framework on which future violence prevention programs can be designed.

A defect in nurturing in mice lacking the immediate early gene fosB

Although expression of the Fos family of transcription factors is induced by environmental stimuli that trigger adaptive neuronal response, evidence that Fos family members mediate these responses is lacking. To address this issue, mice were generated with an inactivating mutation in the fosB gene. fosB mutant mice are profoundly deficient in their ability to nurture young animals but are normal with respect to other cognitive and sensory functions. The nurturing defect is likely due to the absence of FosB in the preoptic area, a region of the hypothalamus that is critical for nurturing. These observations suggest that a transcription factor controls a complex behavior by regulating a specific neuronal circuit and indicate that nurturing in mammals has a genetic component.

Cryptococcal meningitis in patients with the acquired immunodeficiency syndrome

The optimum therapy for cryptococcal meningitis in patients with the acquired immunodeficiency syndrome (AIDS) remains unresolved. Traditional therapy consists of amphotericin B with or without flucytosine. Obstacles exist in administering these agents to patients with AIDS. Mortality rates during initial therapy are relatively high. Given the lack of proved benefit, we do not recommend adding flucytosine to amphotericin B routinely. The search for more efficacious and less toxic agents continues. The oral triazoles, especially fluconazole, have increased the options for treatment of this disease. New strategies and novel approaches in managing cryptococcal meningitis in patients with AIDS continue to be developed.

Continuities in emotion understanding from three to six years

As part of a longitudinal study, 47 children who were tested on their understanding of basic emotions when they were 3 years old were tested again at 6 on their understanding of conflicting emotions. Significant stability in individual differences was found over this 3-year period. Antecedents to emotion understanding at 3 continued to be significantly related to children's understanding at 6, including participation in discourse about causality, positive interaction with older siblings, and language ability. Girls outperformed boys, and there was a suggestion that the girls' understanding of emotions was more closely associated than the boys' with the quality of their sibling relationships. Children's concurrent reports of negative experiences at home and at school were related to their sensitivity to the experience of ambivalent emotions. The results are discussed with respect to the social origins and implications of this core aspect of children's social-cognitive development.

Why talk about mental states? The significance of children's conversations with friends, siblings, and mothers

Natural language data from 38 47-month-olds recorded at home in unstructured observations were analyzed and comparisons made of characteristics of mental state term use in child-friend, child-sibling, and child-mother dyads. Significantly more references to mental states were made by the children in conversations with siblings and friends than with mothers. Frequent use of mental state terms by both partners was related to cooperative interaction in both child-friend and child-sibling dyads and several associations were found with measures of language fluency, gender, and maternal education, although these varied across the 2 dyads. Children's use of mental state terms in conversations with siblings and friends was correlated with their performance on two false belief measures. Results highlight the importance of extending investigations into the social implications of the development of children's "theories of mind."

Integrating Ecology into Natural Resource Management Policy

Traditional natural resource management policy has largely focused on implementing prescriptive solutions to maximize a production function. The fundamental assumptions of this approach were: (1) that ecosystems behaved in a linear, deterministic manner; (2) that there was general community agreement on the value of different ecosystem services; and (3) that land managers would accept and adopt the recommended technology. The result has generally been an unpredictable performance by ecosystems, conflicting expectations among users, and low adoption rates for the outputs of research and development (R&D). We propose that an approach that integrates the fundamentals of nonequilibrium ecology and "soft" systems methodologies to define options, make management decision recommendations, and implement programs will result in improved predictability of ecosystem response, more realistic expectations on the part of users of ecosystem services, and better uptake of technology by land managers.

Characterization of reproductive hormonal dynamics in the perimenopause

Medical therapy for women in the perimenopausal period is controversial, in part due to varying degrees of ovarian hormone secretion characteristic of this time of life. To extend our understanding of the reproductive endocrine milieu of perimenopausal women, we studied 6 cycling women, aged 47 yr and older, for 6 months with daily collections of first morning voided urine. Five additional older reproductive aged (43-47 yr old) women were studied with daily urine and serum sampling for a single menstrual cycle; their urinary hormone data were combined with the former group for menstrual cycle comparisons. Urine was assayed for LH, FSH, estrone conjugates, and pregnanediol glucuronide and normalized for creatinine (Cr). Eleven midreproductive aged (19-38 yr old) normally cycling women, 5 women with well defined premature ovarian failure, and 5 women aged 54 yr and older who were at least 1 yr postmenopausal were used for comparison. Perimenopausal women had shorter follicular phases (11 +/- 2 days vs. 14 +/- 1 days; P = 0.031) and, hence, shorter menstrual cycles than midreproductive aged controls. FSH excretion in perimenopausal women was greater than that in younger women (range of means, 4-32 vs 3-7 IU/g Cr; P = 0.0005). LH secretion was overall greater than that in younger normal subjects (range of means, 1.4-6.8 vs. 1.1-4.2 IU/g Cr; P < 0.026). Overall mean estrone conjugate excretion was greater in the perimenopausal women compared to that in the younger women [76.9 ng/mg Cr (range, 13.1-135) vs. 40.7 ng/mg Cr (range, 22.8-60.3); P = 0.023] and was similarly elevated in both follicular and luteal phases. Luteal phase pregnanediol excretion was diminished in the perimenopausal women compared to that in younger normal subjects (range for integrated pregnanediol, 1.0-8.4 vs. 1.6-12.7 microg/mg Cr/luteal phase; P = 0.015). Compared to postmenopausal women, perimenopausal women had more overall estrone excretion (2.5-6.2 ng/mg Cr in postmenopausal women; P = 0.02) and lower mean FSH (range of means for postmenopause, 24-85 IU/g Cr; P = 0.017) and LH (range for postmenopause, 4.3-14.8 IU/g Cr; P = 0.041). Compared to women with premature menopause, perimenopausal women again had lower FSH (range of means for premature menopause, 36-82 IU/g Cr; P = 0.0022), lower LH (range of means for premature menopause, 5.5-23.8 IU/g Cr; P = 0.0092), borderline higher mean estrone conjugates (range of means for premature menopause, 4-44 ng/mg Cr; P = 0.064), and far longer periods of ovarian activity (one to two cycles in prematurely menopausal women vs. three to six cycles in perimenopausal women). We conclude that altered ovarian function in the perimenopause can be observed as early as age 43 yr and include hyperestrogenism, hypergonadotropism, and decreased luteal phase progesterone excretion. These hormonal alterations may well be responsible for the increased gynecological morbidity that characterizes this period of life.

Length variation, heteroplasmy and sequence divergence in the mitochondrial DNA of four species of sturgeon (Acipenser)

The extent of mtDNA length variation and heteroplasmy as well as DNA sequences of the control region and two tRNA genes were determined for four North American sturgeon species: Acipenser transmontanus, A. medirostris, A. fulvescens and A. oxyrhnychus. Across the Continental Divide, a division in the occurrence of length variation and heteroplasmy was observed that was concordant with species biogeography as well as with phylogenies inferred from restriction fragment length polymorphisms (RFLP) of whole mtDNA and pairwise comparisons of unique sequences of the control region. In all species, mtDNA length variation was due to repeated arrays of 78-82-bp sequences each containing a D-loop strand synthesis termination associated sequence (TAS). Individual repeats showed greater sequence conservation within individuals and species rather than between species, which is suggestive of concerted evolution. Differences in the frequencies of multiple copy genomes and heteroplasmy among the four species may be ascribed to differences in the rates of recurrent mutation. A mechanism that may offset the high rate of mutation for increased copy number is suggested on the basis that an increase in the number of functional TAS motifs might reduce the frequency of successfully initiated H-strand replications.

Polycyclic aromatic hydrocarbons in central London air during 1991 and 1992

The results of monitoring for 18 polycyclic aromatic hydrocarbons (PAH) at Exhibition Road, London, UK during the period from January 1991 to September 1992 are presented. Although both particulate and gaseous PAH were analysed, the results are expressed as total PAH. The PAH measurements are complemented by the simultaneous monitoring of a range of air quality variables. These parameters have been subjected to correlation analysis and the dependence on motor vehicle emissions for many of the PAH species is inferred. The majority of the PAH displayed higher annual mean concentrations during 1991 than previous measurements taken at the same site in 1987. The impact of motor vehicle emission legislation, the increased use of unleaded petrol and the rise in the use of diesel powered motor vehicles are all discussed in the context of the presented results. A pollution event during December 1991 caused significantly increased PAH concentrations. A comparison with PAH data from another site in London indicates good agreement between the two sets of data.

Natural cycle in-vitro fertilization with embryo cryopreservation prior to chemotherapy for carcinoma of the breast

Chemotherapeutic treatment for malignant disease may cause infertility secondary to gonadal failure. In-vitro fertilization (IVF) with embryo cryopreservation prior to chemotherapy has been described as a means of preserving future fertility potential. However, the supraphysiological levels of sex steroids that result from ovarian stimulation for IVF may, at least theoretically, stimulate growth of malignant cells in a patient with a hormonally sensitive tumour such as carcinoma of the breast. This report describes a patient with carcinoma of the breast who underwent IVF in the natural cycle prior to embarking on a course of combination chemotherapy. Of three oocytes retrieved, two fertilized and were cryopreserved. This case represents a novel application of IVF with embryo cryopreservation in the natural cycle. Although embryo thawing and transfer have not yet been attempted, the patient has already benefitted psychologically from having the opportunity to assume an element of control over her reproductive future. Should pregnancy occur, this would be the first report of human pregnancy from cryopreserved embryos obtained in a natural cycle.

A comparison of six enamel treatment procedures for sealant bonding

This in-vitro study evaluated the effectiveness of six different enamel treatment procedures for bonding a dental sealant. Sixty extracted human molar teeth were separated into the following enamel treatment groups (10 teeth each): group 1 (control)-etched with 37% phosphoric acid; group 2-air polished (air abraded) with 45 microns particles of sodium bicarbonate; group 3-air abraded with 50 microns aluminum oxide particles; group 4-etched with 2.5% nitric acid; group 5-air abraded with sodium bicarbonate particles and etched with 37% phosphoric acid; and group 6-air abraded with 50-microns aluminum oxide particles and etched with 37% phosphoric acid. The enamel treatment procedures were accomplished on intact mesial or distal surfaces. Following the enamel treatment, a sealant was bonded to the surfaces using a plastic matrix technique. After 24 hr of water storage at 37 degrees C, the specimens were debonded using an Instron machine. The mean shear bond strengths (MPa) were as follows: group 1-9.19 +/- 1.34 MPa; group 2-2.03 +/- 1.67 MPa; group 3-1.50 +/- 0.93 MPa; group 4-4.99 +/- 1.26 MPa; group 5-11.61 +/- 4.51; and group 6-11.14 +/- 1.70 MPa. Statistical analysis using a one-way ANOVA and Scheffe F-test revealed no significant difference (P > 0.05) among groups 1,5, and 6. However, there was a significant difference (P < 0.05) between groups 1,5, and 6 and the other three groups (2,3, and 4). In conclusion, 37% phosphoric acid treatment of intact enamel, or a combination of air abrasion with sodium bicarbonate or aluminum oxide followed by phosphoric acid, provides significantly higher bond strengths of a sealant material than enamel conditioning with 2.5% nitric acid or air abrasion with sodium bicarbonate or aluminum oxide.

Variability of day 3 follicle-stimulating hormone levels in eumenorrheic women

OBJECTIVE

To assess the intercycle variability of early follicular follicle-stimulating hormone (FSH) and estradiol (E2) levels in eumenorrheic women according to age.

STUDY DESIGN

Forty-eight female volunteers with regular menstrual cycles were studied. Serum samples were obtained on cycle day 3 in multiple cycles over a one-year period. Serum was also obtained on consecutive cycle days 2, 3 or 4 in a single cycle in 20 participants. All samples were assayed for FSH and E2 by radioimmunoassay.

RESULTS

In women under 40 years of age, all initial day 3 FSH levels were < 20 mIU/mL, and 15% of subjects had a subsequently elevated day 3 FSH level (> or = 20 mIU/mL) within the year. In eight women 40-44 years of age, 75% had an initial day 3 FSH level < 20 mIU/mL, but half of them subsequently had an elevated level, > 20 mIU/mL, within the year. Between cycle days 2, 3 and 4, FSH (coefficient of variation [CV] = 14.8%, 95% confidence interval (CI) = 11.4-18.3%) varied less than E2 (CV = 31.1%, 95% CI = 21.5-40.6%).

CONCLUSION

A single day 3 FSH level < 20 mIU/mL is highly predictive of all subsequent values within a year and occurred only in women under 40. An FSH level drawn on cycle day 2 or 4 will probably be within 18% of the day 3 value, but the E2 level may vary by up to 40%.

The pharmacological modulation of angiogenesis in chronic granulomatous inflammation

Angiogenesis is required for the progression of chronic inflammation, and agents that alter it can affect the development of inflammation and the consequent tissue destruction. However, in vivo quantification of neovascularization and its modulation by angiostatic and angiogenic agents is difficult. Studies have relied on reported effects of drugs on embryonic and tumor vasculature to infer angiomodulatory actions. We have characterized a vascular casting method that incorporates carmine in gelatin. Vascularity expressed as micrograms dye/mg dry tissue (vascularity index, V.I.) was studied in the murine chronic granulomatous air pouch. Carmine was retained within the vasculature by gelatin, and its content increased before the granulomatous tissue, resulting in a V.I. peak at 5 days, regression and a second peak over 14 to 28 days. The modulation of prostaglandin synthesis, plasma exudation and vasomotor tone showed that the carmine V.I. remained unaffected, unlike Evans blue, illustrating independence from acute inflammatory processes such as vasomotor tone and plasma exudation. The angiogenic stimulus p.o. heparin increased the V.I., whereas a sub-anti-inflammatory dose of cortisone with 1000 U heparin reduced it. Higher doses of heparin overcame this. The potent angiostatic steroid tetrahydrocortisol significantly reduced the V.I. in the absence of heparin. Cortisone exhibited independence from heparin on topical administration in hyaluronan. Dexamethasone inhibited granulomatous tissue development with a resulting increase in V.I. These observations indicated the differential effects of angiostatic and anti-inflammatory steroid activity. The pharmacological modulation of angiogenesis in inflammation can therefore be quantified.

Changes in casein composition of goats' milk during the course of lactation: physiological inferences and technological implications

Five British Saanen goats were milk sampled during the first 39 weeks of lactation to determine changes in casein composition. Caseins were separated by anion- and cation-exchange FPLC to determine the relative amounts of the individual caseins. Acid, alkaline and SDS-PAGE were used to determine possible genetic polymorphisms and observe any lactational changes. Total casein nitrogen was determined using a micro-Kjeldahl method and this allowed the concentrations of individual caseins to be calculated. The milk of one animal, which had the deduced genotype alpha s1-CnAB, showed higher concentrations of both total and alpha s1-casein. The remainder of the group were either heterozygous alpha s1-CnBE or, more probably, homozygous alpha s1-CnE and produced milk of a generally lower protein concentration. Both FPLC and PAGE results showed that the relative amounts and concentrations of alpha s2-casein decreased with stage of lactation, consistent with its susceptibility to proteolysis. The relative amounts of the breakdown products of plasmin attack on beta-casein, gamma-caseins, were highly negatively correlated with milk yield (r = -0.942, P < 0.001) in the declining phase of lactation, reflecting the gradual involution of the gland at this time. The relative amount of kappa-casein increased by approximately 50% after peak lactation and its concentration almost doubled near the end of lactation. These compositional changes may alter the processing qualities of goats' milk in relation to cheese production.

Root of the universal tree of life based on ancient aminoacyl-tRNA synthetase gene duplications

Universal trees based on sequences of single gene homologs cannot be rooted. Iwabe et al. [Iwabe, N., Kuma, K.-I., Hasegawa, M., Osawa, S. & Miyata, T. (1989) Proc. Natl. Acad. Sci. USA 86, 9355-9359] circumvented this problem by using ancient gene duplications that predated the last common ancestor of all living things. Their separate, reciprocally rooted gene trees for elongation factors and ATPase subunits showed Bacteria (eubacteria) as branching first from the universal tree with Archaea (archaebacteria) and Eucarya (eukaryotes) as sister groups. Given its topical importance to evolutionary biology and concerns about the appropriateness of the ATPase data set, an evaluation of the universal tree root using other ancient gene duplications is essential. In this study, we derive a rooting for the universal tree using aminoacyl-tRNA synthetase genes, an extensive multigene family whose divergence likely preceded that of prokaryotes and eukaryotes. An approximately 1600-bp conserved region was sequenced from the isoleucyl-tRNA synthetases of several species representing deep evolutionary branches of eukaryotes (Nosema locustae), Bacteria (Aquifex pyrophilus and Thermotoga maritima) and Archaea (Pyrococcus furiosus and Sulfolobus acidocaldarius). In addition, a new valyl-tRNA synthetase was characterized from the protist Trichomonas vaginalis. Different phylogenetic methods were used to generate trees of isoleucyl-tRNA synthetases rooted by valyl- and leucyl-tRNA synthetases. All isoleucyl-tRNA synthetase trees showed Archaea and Eucarya as sister groups, providing strong confirmation for the universal tree rooting reported by Iwabe et al. As well, there was strong support for the monophyly (sensu Hennig) of Archaea. The valyl-tRNA synthetase gene from Tr. vaginalis clustered with other eukaryotic ValRS genes, which may have been transferred from the mitochondrial genome to the nuclear genome, suggesting that this amitochondrial trichomonad once harbored an endosymbiotic bacterium.

Nonprescription, padded, lightweight support socks in treatment of mild to moderate lower extremity venous insufficiency

Currently, strength greater than 20 mm Hg of compression is considered necessary for support hose used to treat symptomatic venous insufficiency in lower extremities. This strength is frequently uncomfortable, which reduces compliance and therefore clinical effectiveness. Whether more comfortable, nonprescription, light-compression support hose is effective in the treatment of mild to moderate venous insufficiency was investigated in 36 men with subjective complaints and objective signs (per Doppler ultrasound) of lower extremity venous insufficiency. All participants wore padded, light-compression (6 mm Hg), crew-height socks for 1 month. Then, participants were assigned to one of two groups on the basis of initial Doppler results. The half with the worst results wore stronger-compression (12 mm Hg) over-the-calf support socks, on the assumption that patients with worse venous insufficiency would require more support; those with the better Doppler results continued to wear the light-compression socks. Participants were retested at monthly intervals for 3 months. In each group, data indicated that the venous insufficiency for all patients improved objectively and subjectively. Many of the objective venous values improved with either statistical or highly statistical significance--specifically deep venous valve function, superficial venous valve functions, and venous capacity--without statistically altering arterial function. Improvement occurred in the first month of the trial and continued throughout the study. The use of light-compression support socks is effective and should be considered as a first line of therapy in treatment of mild to moderate venous insufficiency.

Diminished function of the somatotropic axis in older reproductive-aged women

Circulating GH and insulin-like growth factor-I (IGF-I) levels in adults generally fall with age. Studies in aging women have rarely controlled for menstrual cycle stage or status or body mass index. We hypothesized that GH and IGF-I levels in reproductive-aged women fall with age despite the stimulatory effects of endogenous estradiol (E2). Eight older reproductive-aged women (aged 42-46 yr) with regular menses, of normal weight, and in good health were compared to a group of eight young control subjects (aged 19-34 yr). Daytime frequent blood sampling was performed in the early follicular phase of the menstrual cycle to characterize pulsatile GH and LH concentrations. Pooled samples were also analyzed for IGF-I, E2, progesterone, and FSH levels. Older reproductive-aged women had lower 12-h integrated daytime GH concentrations (mean +/- SE, 171 +/- 35 vs. 427 +/- 130 micrograms min/L; P = 0.036) than younger controls and a strong trend for lower IGF-I levels (22.7 +/- 2.1 vs. 31.3 +/- 3.5 nmol/L; P = 0.055) than younger controls despite having higher circulating E2 on the day of sampling (368 +/- 51 vs. 167 +/- 20 pmol/L; P = 0.002). We conclude that older reproductive-aged women have lower daytime GH concentrations than younger controls despite having higher E2 levels on the day of sampling and overall normal gonadal hormone parameters.

Tempo, mode, the progenote, and the universal root

Early cellular evolution differed in both mode and tempo from the contemporary process. If modern lineages first began to diverge when the phenotype-genotype coupling was still poorly articulated, then we might be able to learn something about the evolution of that coupling through comparing the molecular biologies of living organisms. The issue is whether the last common ancestor of all life, the cenancestor, was a primitive entity, a progenote, with a more rudimentary genetic information-transfer system. Thinking on this issue is still unsettled. Much depends on the placement of the root of the universal tree and on whether or not lateral transfer renders such rooting meaningless.

Evolutionary relationships of bacterial and archaeal glutamine synthetase genes

Glutamine synthetase (GS), an essential enzyme in ammonia assimilation and glutamine biosynthesis, has three distinctive types: GSI, GSII and GSIII. Genes for GSI have been found only in bacteria (eubacteria) and archaea (archaebacteria), while GSII genes only occur in eukaryotes and a few soil-dwelling bacteria. GSIII genes have been found in only a few bacterial species. Recently, it has been suggested that several lateral gene transfers of archaeal GSI genes to bacteria may have occurred. In order to study the evolution of GS, we cloned and sequenced GSI genes from two divergent archaeal species: the extreme thermophile Pyrococcus furiosus and the extreme halophile Haloferax volcanii. Our phylogenetic analysis, which included most available GS sequences, revealed two significant prokaryotic GSI subdivisions: GSI-alpha and GSI-beta. GSI-alpha-genes are found in the thermophilic bacterium, Thermotoga maritima, the low G+C Gram-positive bacteria, and the Euryarchaeota (includes methanogens, halophiles, and some thermophiles). GSI-beta-type genes occur in all other bacteria. GSI-alpha- and GSI-beta-type genes also differ with respect to a specific 25-amino-acid insertion and adenylylation control of GS enzyme activity, both absent in the former but present in the latter. Cyanobacterial genes lack adenylylation regulation of GS and may have secondarily lost it. The GSI gene of Sulfolobus solfataricus, a member of the Crenarchaeota (extreme thermophiles), is exceptional and could not be definitely placed in either subdivision.