Structural and functional studies of FkpA from Escherichia coli, a cis/trans peptidyl-prolyl isomerase with chaperone activity

The protein FkpA from the periplasm of Escherichia coli exhibits both cis/trans peptidyl-prolyl isomerase (PPIase) and chaperone activities. The crystal structure of the protein has been determined in three different forms: as the full-length native molecule, as a truncated form lacking the last 21 residues, and as the same truncated form in complex with the immunosuppressant ligand, FK506. FkpA is a dimeric molecule in which the 245-residue subunit is divided into two domains. The N-terminal domain includes three helices that are interlaced with those of the other subunit to provide all inter-subunit contacts maintaining the dimeric species. The C-terminal domain, which belongs to the FK506-binding protein (FKBP) family, binds the FK506 ligand. The overall form of the dimer is V-shaped, and the different crystal structures reveal a flexibility in the relative orientation of the two C-terminal domains located at the extremities of the V. The deletion mutant FkpNL, comprising the N-terminal domain only, exists in solution as a mixture of monomeric and dimeric species, and exhibits chaperone activity. By contrast, a deletion mutant comprising the C-terminal domain only is monomeric, and although it shows PPIase activity, it is devoid of chaperone function. These results suggest that the chaperone and catalytic activities reside in the N and C-terminal domains, respectively. Accordingly, the observed mobility of the C-terminal domains of the dimeric molecule could effectively adapt these two independent folding functions of FkpA to polypeptide substrates.     

Primate life history,social dynamics,ecology, and conservation: Contributions from long-term research in Área de Conservación Guanacaste,Costa Rica

Research on non-human primates in the endangered tropical dry forest of Sector Santa Rosa (SSR), Área de Conservación Guanacaste (ACG), was launched in 1983 and is now one of the longest running studies of primates globally. Such continuous study provides a rare opportunity to ask questions that are only answerable through decades-long monitoring of these long-lived monkeys. In turn, the mounting data generated by long-term study, including knowledge of lifetime reproductive success, familial relatedness, comprehensive behavioral and dietary repertoires, and patterns of inter- and intra-annual variation in forest productivity, provide diverse opportunities to researchers, and facilitate studies that are of shorter duration. Here, we review some of the contributions of our longitudinal research on white-faced capuchins and Geoffroy's spider monkeys, together with newer studies on mantled howler monkeys. We begin by synthesizing findings from our research on demography, dispersal, social relationships, and reproduction. These life history and social traits interact with their foraging and sensory ecology, which we review next. We end by highlighting how the longitudinal study of primates in Sector Santa Rosa has made direct and indirect contributions to the conservation of the critically endangered dry forest biome and its inhabitants, as well as to education, community, and forest restoration initiatives. In particular, we focus our review on how long-term research is uniquely positioned to make key contributions spanning different topical areas.     

The Effect of Gender-Affirming Hormone Therapy on Serum Creatinine in Transgender Individuals

ObjectiveTo describe the changes in serum creatinine (Cr) levels after the initiation of gender-affirming hormone therapy (GAHT) in transgender individuals to better understand the expected changes and interpretation of laboratory values in this population.MethodsA retrospective chart review of all adult transgender patients initiated on GAHT at Mayo Clinic from January 2011 to October 2019 was completed. Laboratory values were obtained prior to initiating GAHT and at 3, 6, and 12 months after initiating GAHT. Baseline Cr values were compared with Cr values at 3, 6, and 12 months after initiating GAHT in transgender men (TM) on testosterone and transgender women (TW) on estradiol and antiandrogens.ResultsA total of 84 TW (median age of 30 years) and 24 TM (median age of 23 years) were included for analysis. Following a matched pair analysis of TW, Cr values were found to be significantly decreased by ?0.03 at 3 months (P = .04), ?0.10 at 6 months (P < .01), and ?0.07 at 12 months (P < .01) compared with baseline values. Following a matched pair analysis of TM, Cr values were found to be significantly increased, on average, by 0.14 at 3 months (P = .04), 0.21 at 6 months (P = .016), and 0.15 at 12 months (P = .003) compared with baseline values.ConclusionIn TW and TM, a change in Cr level was seen as early as 3 months toward their affirmed gender after initiating GAHT. Clinicians can use Cr levels established at 6 months as new baseline values, as these changes continue to persist up to 12 months.     

Comparison of cytoplasmic ribosomal proteins of gateway barley and its mutant

The proteins of the cytoplasmic ribosomes isolated from dry embryos of Gateway barley and its virescens mutant were compared by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The monosomes of both the lines gave similar patterns with 60 basic proteins. Upon dissociation of the monosomes, for the mutant, the basic proteins of the large subunits migrated more slowly than those of the normal and lacked three proteins but had three additional spots. Also, the proteins of the small subunits differed. The mutant lacked three of the proteins present in the normal but had three additional spots. Therefore, the large and small subunits contained a total of 34 and 41 basic proteins, respectively, in both the lines. There were several spots with identical electrophoretic mobilities in the small and large subunits of these two lines.     

Heterologous expression of glucose oxidase in the yeast <Emphasis Type="Italic">Kluyveromyces marxianus</Emphasis>

Background  

In spite of its advantageous physiological properties for bioprocess applications, the use of the yeast Kluyveromyces marxianus as a host for heterologous protein production has been very limited, in constrast to its close relative Kluyveromyces lactis. In the present work, the model protein glucose oxidase (GOX) from Aspergillus niger was cloned into K. marxianus CBS 6556 and into K. lactis CBS 2359 using three different expression systems. We aimed at verifying how each expression system would affect protein expression, secretion/localization, post-translational modification, and biochemical properties.     

Magnesium replacement by polyamines in higher plant cell-free polyphenylalanine synthesis

The characteristics and specific requirements for the formation of polyphenylalanine from Phe-[¹⁴C] in a barley ribosome cell-free incorporation system were detailed. The polyamines spermine, spermidine and putrescine, and the inorganic cations Ca²⁺, Ba²⁺ and Mn²⁺ demonstrated different capabilities for replacing the Mg²⁺ requirement in the incorporation system. Spermine was extremely efficient in this respect, followed by spermidine; all of the cations tested showed discrete concentration ranges of effectiveness. The data supported the suggestion that, at least to a certain extent, the cation requirement for protein syntheis may be non-specific.     

The changing estrogen content of the nuclear fraction of human myometrium during labor

The cytosol and nuclear fractions were prepared from 32 pieces of myometrlum obtained from 20 elective cesarean sections (regarded as typical of quiescent pregnancy (P)) and 12 emergency cesareans (performed after labor had started and therefore taken as typical of labor (L)). The nuclear fraction was purified by standard procedures. All protein-bound estrogen was released from the nuclear fractions, and the released estrogen simultaneously solubilized by denaturation with ethanol. The estriol (E₃) and estradiol (E₂) content of the alcohol solutions were assayed by radioimmunoassay with highly specific antisera for E₃ and E₂. In the L group, average E₃ content was slightly (not significantly) lower, and average E₂ content was significantly (P < 0.005) higher, than in the P group. The E₃/E₂ ratio decreased dramatically (P < 0.001) during this change from P to L.     

Linkage analysis of five new genetic markers of the oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae).

Five new autosomal recessive genes are described in the oriental fruit fly, Bactrocera dorsalis (Hendel). These genetic markers are associated into three linkage groups. The matte (mt) gene is linked to the previously described mandarin red (ma) gene, and the white puparium (wp) gene is linked to the white eye (we) and amethyst (am) loci. The third designated linkage group has the yellow eye (ye) marker. The we/we homozygote is epistatic to ye/ye, and each is epistatic to am/am and ma/ma.     

Which is the best lipid-modifying strategy in metabolic syndrome and diabetes: fibrates, statins or both?

Although less clinical intervention studies have been performed with fibrates than with statins, there are evidences indicating that fibrates may reduce risk of cardiovascular events. The potential clinical benefit of the fenofibrate will be specified by the ongoing Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study, which rationale, methods and aims have been just published. Controlled clinical trials show similar or even greater cardiovascular benefits from statins-based therapy in patient subgroups with diabetes compared with overall study populations. Therefore, statins are the drug of first choice for aggressive lipid lowering actions and reducing risk of coronary artery disease in these patients. However, current therapeutic use of statins as monotherapy is still leaving many patients with mixed atherogenic dyslipidemia at high risk for coronary events. A combination statin/fibrate therapy may be often necessary to control all lipid abnormalities in patients with metabolic syndrome and diabetes adequately, since fibrates provide additional important benefits, particularly on triglyceride and HDL-cholesterol levels. Thus, this combined therapy concentrates on all the components of the mixed dyslipidemia that often occurs in persons with diabetes or metabolic syndrome, and may be expected to reduce cardiovascular morbidity and mortality. Safety concerns about some fibrates such as gemfibrozil may lead to exaggerate precautions regarding fibrate administration and therefore diminish the use of the seagents. However, other fibrates, such as bezafibrate and fenofibrate appear to be safer and better tolerated. We believe that a proper co-administration of statins and fibrates, selected on basis of their safety, could be more effective in achieving a comprehensive lipid control as compared with monotherapy.