Evolution of the 28S ribosomal RNA gene in anurans: regions of variability and their phylogenetic implications

Fifteen restriction sites were mapped to the 28S ribosomal RNA gene of individuals representing 54 species of frogs, two species of salamanders, a caecilian, and a lungfish. Eight of these sites were present in all species examined, and two were found in all but one species. Alignment of these conserved restriction sites revealed, among anuran 28S rRNA genes, five regions of major length variation that correspond to four of 12 previously identified divergent domains of this gene. One of the divergent domains (DD8) consists of two regions of length variation separated by a short segment that is conserved at least throughout tetrapods. Most of the insertions, deletions, and restriction-site variations identified in the 28S gene will require sequence-level analysis for a detailed reconstruction of their history. However, an insertion in DD9 that is coextensive with frogs in the suborder Neobatrachia, a BstEII site that is limited to representatives of two leptodactylid subfamilies, and a deletion in DD10 that is found only in three ranoid genera are probably synapomorphies.      

The linkage of sugar phosphate polymer to peptidoglycan in walls of Micrococcus sp. 2102.

1. Protein-free walls of Micrococcus sp. 2102 contain peptidoglycan, poly-(N-acetylglucosamine 1-phosphate) and small amounts of glycerol phosphate. 2. After destruction of the poly-(N-acetylglucosamine 1-phosphate) with periodate, the glycerol phosphate remains attached to the wall, but can be removed by controlled alkaline hydrolysis. The homogeneous product comprises a chain of three glycerol phosphates and an additional phosphate residue. 3. The poly-(N-acetylglucosamine 1-phosphate) is attached through its terminal phosphate to one end of the tri(glycerol phosphate). 4. The other end of the glycerol phosphate trimer is attached through its terminal phosphate to the 3-or 4-position of an N-acetylglucosamine. It is concluded that the sequence of residues in the sugar 1-phosphate polymer-peptidoglycan complex is: (N-acetylglucosamine 1-phosphate)24-(glycerol phosphate)3-N-acetylglucosamine 1-phosphate-muramic acid (in peptidoglycan). Thus in this organism the phosphorylated wall polymer is attached to the peptidoglycan of the wall through a linkage unit comprising a chain of three glycerol phosphate residues and an N-acetylglucosamine 1-phosphate, similar to or identical with the linkage unit in Staphylococcus aureus H.     

Parathyroid hormone related protein and hypercalcaemia in breast cancer.

OBJECTIVE--To see whether parathyroid hormone related protein has a humoral role in breast cancer. DESIGN--Plasma concentrations and tumour expression of parathyroid hormone related protein were determined (by two site immunoradiometric assay and immunohistochemistry respectively) in women with breast cancer and related to the presence of bone metastases and serum calcium concentrations. SUBJECTS--Plasma concentrations of parathyroid hormone related protein were measured in 57 women with early breast cancer without apparent bone metastases, 28 women with bone metastases, and 13 women with bone metastases and hypercalcaemia. Tissue positivity for parathyroid hormone related protein was determined retrospectively in 106 primary breast tumours from women without apparent bone metastases and 72 tumours from women with bone metastases, 25 of whom subsequently developed hypercalcaemia. RESULTS--Plasma parathyroid hormone related protein concentrations were detectable (greater than 0.23 pmol/l) in 12 (92%) of the 13 hypercalcaemic patients with bone metastases compared with 10 (36%) of the 28 normocalcaemic patients with bone metastases and five (9%) of the 57 normocalcaemic patients without bone metastases. Parathyroid hormone related protein concentrations were significantly higher in hypercalcaemic than normocalcaemic patients with bone metastases. Tumour staining was positive for parathyroid hormone related protein in 22 (88%) of the 25 primary breast cancers from patients with bone metastases. Tumour staining was positive for parathyroid hormone related protein in 22 (88%) of the 25 primary breast cancers from patients with bone metastases who later developed hypercalcaemia compared with 25 (53%) of the 47 from women in this group who remained normocalcaemic and 55 (52%) of the 106 early breast cancers from women without known metastases. CONCLUSION--Tumour derived parathyroid hormone related protein may have an important humoral role in hypercalcaemia associated with metastatic breast cancer.     

Variation in the ribosomal internal transcribed spacers and 5.8S rDNA among five species of Acropora (Cnidaria; Scleractinia): patterns of variation consistent with reticulate evolution

The ITS sequences of Acropora spp. are the shortest so far identified in any metazoan and are among the shortest seen in eukaryotes; ITS1 was 70-80 bases, and ITS2 was 100-112 bases. The ITS sequences were also highly variable, but base composition and secondary structure prediction indicate that divergent sequence variants are unlikely to be pseudogenes. The pattern of variation was unusual in several other respects: (1) two distinct ITS2 types were detected in both A. hyacinthus and A. cytherea, species known to hybridize in vitro with high success rates, and a putative intermediate ITS2 form was also detected in A. cytherea; (2) A. valida was found to contain highly (29%) diverged ITS1 variants; and (3) A. longicyathus contained two distinct 5.8S rDNA types. These data are consistent with a reticulate evolutionary history for the genus Acropora.      

Absence of DICER in Monocytes and Its Regulation by HIV-1

MicroRNAs (miRNAs) are a class of small RNA molecules that function to control gene expression and restrict viral replication in host cells. The production of miRNAs is believed to be dependent upon the DICER enzyme. Available evidence suggests that in T lymphocytes, HIV-1 can both suppress and co-opt the host''s miRNA pathway for its own benefit. In this study, we examined the state of miRNA production in monocytes and macrophages as well as the consequences of viral infection upon the production of miRNA. Monocytes in general express low amounts of miRNA-related proteins, and DICER in particular could not be detected until after monocytes were differentiated into macrophages. In the case where HIV-1 was present prior to differentiation, the expression of DICER was suppressed. MicroRNA chip results for RNA isolated from transfected and treated cells indicated that a drop in miRNA production coincided with DICER protein suppression in macrophages. We found that the expression of DICER in monocytes is restricted by miR-106a, but HIV-1 suppressed DICER expression via the viral gene Vpr. Additionally, analysis of miRNA expression in monocytes and macrophages revealed evidence that some miRNAs can be processed by both DICER and PIWIL4. Results presented here have implications for both the pathology of viral infections in macrophages and the biogenesis of miRNAs. First, HIV-1 suppresses the expression and function of DICER in macrophages via a previously unknown mechanism. Second, the presence of miRNAs in monocytes lacking DICER indicates that some miRNAs can be generated by proteins other than DICER.     

Developmental Changes in Direct and Indirect Defenses in the Young Leaves of the Neotropical Tree Genus Inga (Fabaceae)

Plant fitness is affected by herbivory, and in moist tropical forests, 70 percent of herbivore damage occurs on young leaves. Thus, to understand the effects of herbivory on tropical plant fitness, it is necessary to understand how tropical young leaves survive the brief, but critical, period of susceptibility. In this study, we surveyed three species of Inga during young leaf expansion. Three classes of toxic secondary metabolites (phenolics, saponins, and tyrosine), extrafloral nectar production, leaf area, and extrafloral nectary area were measured at randomly assigned young leaf sizes. In addition, all defenses were compared for potential trade‐offs during leaf expansion. No trade‐offs among defenses were found, and the concentration of all defenses, except tyrosine, decreased during leaf expansion. We suggest that plants continued to increase phenolic and saponin content, but at a rate that resulted in decreasing concentrations. In contrast, tyrosine content per leaf steadily increased such that a constant concentration was maintained regardless of young leaf size. Nectar production remained constant during leaf expansion, but, because young leaf area increased by tenfold, the investment in extrafloral nectar per leaf area significantly decreased. In addition, nectary area did not change during leaf expansion and therefore the relative size of the nectary significantly decreased during young leaf expansion. These results support the predictions of the optimal defense hypothesis and demonstrate that the youngest leaves have the highest investment in multiple defenses, most likely because they have the highest nitrogen content and are most susceptible to a diversity of herbivores.     

Is Maternal Marriage Beneficial for Low-Income Adolescents?

The present study investigated the association of mothers' marriage and changes in young adolescents' cognitive and socioemotional development and changes in family processes. Analyses employed longitudinal data from the Three-City Study to track maternal partnerships for 860 low-income adolescents (10–14 years-old in Wave 1) across a 16 month period. No short-term benefits or risks emerged for youth when mothers entered marriage, with few changes in family or maternal functioning linked with marriage formation as well. In contrast, adolescents in stably married families experienced improved academic, behavioral, and psychological well-being compared to youth in stable cohabiting or single-parent families. Stable marriage was similarly linked to improvements across multiple domains of home and mothers' functioning. These patterns were not moderated by the male partner's identity (biological father or stepfather). Results support the benefits of stable marriage on youth development, but suggest that policies supporting movements into new marriages may not result in improved adolescent or family functioning, at least in the short term.     

Evidence for "twisted plane" undulations in golden hamster sperm tails

Motile spermatozoa from the golden hamster have been arrested by rapid freezing and then fixed with glutaraldehyde at low temperature after substitution with ethylene glycol. As far as can be judged, the flagellar waveforms thus stabilized are similar to those seen in living sperm; in contrast, fixation in glutaraldehyde, without prior freezing, induces agonal changes in flagellar conformation. The characteristics waveform after freeze substitution contains three bends. Approx. half of these flagella are entirely planar. The rest are three dimensional, with the third bend displaced in a regular way from the plane containing the proximal two bends. From the geometry of these flagella, it is concluded that the plane of action of a given bending cycle undergoes a clockwise twist (from a forward viewpoint) as the cycle is succeeded by new bending cycles. This "twisted plane" undulation is quite different from helical movement. The twisting seems to occur abruptly, between cycles, as if each bending cycle has a preferred plane of action. The mechanism underlying the twisting is uncertain. However, on the basis of the angular displacements between the preferred planes, and the findings from electron microscopy, the following idea is presented as a working hypothesis: that, if the most proximal plane of bending is topographically determined by peripheral doublet 1, then successive distal planes of action are influenced predominantly by doublets 2, 3, etc., in clockwise sequence. The merits and weaknesses of this hypothesis are discussed.     

Impact of human activities on the reproduction of Hooded Vultures Necrosyrtes monachus in Burkina Faso

During the last decades, the critically endangered Hooded Vulture Necrosyrtes monachus has strongly declined across its African range. Although direct persecution has been suggested as a major cause of this decline, little is known about the impact of humans on reproductive output in West Africa. We studied the impact of human activities on the reproductive output of Hooded Vultures in the Garango area of Burkina Faso. Twenty and 56 nesting attempts were monitored, respectively, during the breeding season in 2013/14 and 2014/15, to determine reproductive success and identify causes of nest failure. Annual breeding success varied between 0.68 and 0.71 chicks fledged per breeding pair per year and productivity was assessed at 0.57 chicks fledged per territorial pair in 2014/15. The main threats imposed by humans were poaching of eggs, chicks and collection of nest materials, leading to 20% (13 out of 64 breeding attempts) of nest failures over the two years. An additional important reason for nest failure was the pruning and (partial) cutting of nest trees. Despite this high level of human interference, we found that Hooded Vulture nest success increased with proximity to human settlements, probably because breeding vultures benefit from protection by people against persecution and disturbance.     

Increased endogenous H2S generation by CBS, CSE, and 3MST gene therapy improves ex vivo renovascular relaxation in hyperhomocysteinemia

Hydrogen sulfide (H(2)S) has recently been identified as a regulator of various physiological events, including vasodilation, angiogenesis, antiapoptotic, and cellular signaling. Endogenously, H(2)S is produced as a metabolite of homocysteine (Hcy) by cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3MST). Although Hcy is recognized as vascular risk factor at an elevated level [hyperhomocysteinemia (HHcy)] and contributes to vascular injury leading to renovascular dysfunction, the exact mechanism is unclear. The goal of the current study was to investigate whether conversion of Hcy to H(2)S improves renovascular function. Ex vivo renal artery culture with CBS, CSE, and 3MST triple gene therapy generated more H(2)S in the presence of Hcy, and these arteries were more responsive to endothelial-dependent vasodilation compared with nontransfected arteries treated with high Hcy. Cross section of triple gene-delivered renal arteries immunostaining suggested increased expression of CD31 and VEGF and diminished expression of the antiangiogenic factor endostatin. In vitro endothelial cell culture demonstrated increased mitophagy during high levels of Hcy and was mitigated by triple gene delivery. Also, dephosphorylated Akt and phosphorylated FoxO3 in HHcy were reversed by H(2)S or triple gene delivery. Upregulated matrix metalloproteinases-13 and downregulated tissue inhibitor of metalloproteinase-1 in HHcy were normalized by overexpression of triple genes. Together, these results suggest that H(2)S plays a key role in renovasculopathy during HHcy and is mediated through Akt/FoxO3 pathways. We conclude that conversion of Hcy to H(2)S by CBS, CSE, or 3MST triple gene therapy improves renovascular function in HHcy.