“Reverse” sexual dichromatism in a Neotropical frog

Sexual dichromatism is widespread among animals, but examples of “reverse” sexual dichromatism, in which females are more brightly colored than males, are extremely rare. We discovered a unique case of reverse sexual dichromatism in the golden rocket frog (Anomaloglossus beebei), a diurnal Neotropical frog. Females are bright “golden” in color, and males are drab tan with brown pigmentation that darkens when they are calling. Here, we document this color variation with calibrated digital photography and further show that there is no evidence for sex‐specific habitat matching; both sexes live in the same well‐lit habitat on green bromeliad leaves. Our results suggest that color variation in this species is an intraspecific signal and provide an important exception to the general expectation that males are more visually conspicuous in species with conventional sex roles.     

Differential staining of chromatids reveals substitution of BUdR for thymine in “old” DNA strands

Metaphases collected from cultures grown for three cell cycles in 5-bromodeoxyuridine (BUdR) and then for one or two further cell cycles without BUdR show persistence of differentially FPG-stained chromatids. The cell cycle length is not altered by the presence of BUdR. After removal of BUdR, the cells synthesize DNA and incorporate mainly thymine, as demonstrated by density gradient analysis of DNA. Our observations suggest that chromatids with T-B DNA stain lightly after removal of BUdR, in contrast with their dark staining when cultures are maintained in BUdR. Thus, in any experimental condition, there is a correspondence between the nature (T-DNA or B-DNA) of the “old” DNA strands and the FPG-staining (dark or light) of the chromatids.     

Modified method of differential staining of sister chromatids]

A modified method of obtaining differential staining of sister chromatids is described. It is simple, rapid, and effective, and at the same time inexpensive and accessible, since it allows one to use available reagents. When 5-bromdeoxyuridine was administered 24 hours before fixation into the Chinese hamster cell culture the percentage of metaphases with a differential chromatid staining constituted 95--98, and when this substance was administered 28 hours before fixation into the human lymphocyte culture this percentage varied from 75 to 92, depending on the individual. The mean number of sister chromatid exchanges in human lymphocytes failed to depend on the time of fixation.     

“Inflammatory” Cytokines

If cytokines are constitutively expressed by and act on neurons in normal adult brain, then we may have to modify our current view that they are predominantly inflammatory mediators. We critically reviewed the literature to determine whether we could find experimental basis for such a modification. We focused on two "proinflammatory" cytokines, interleukin (IL)-1 and tumor necrosis factor-alpha (TNFalpha) because they have been most thoroughly investigated in shaping our current thinking. Evidence, although equivocal, indicates that the genes coding for these cytokines and their accessory proteins are expressed by neurons, in addition to glial cells, in normal brain. Their expression is region- and cell type-specific. Furthermore, bioactive cytokines have been extracted from various regions of normal brain. The cytokines' receptors selectively are present on all neural cell types, rendering them responsive to cytokine signaling. Blocking their action modifies multiple neural "housekeeping" functions. For example, blocking IL-1 or TNFalpha by several independent means alters regulation of sleep. This indicates that these cytokines likely modulate in the brain behavior of a normal organism. In addition, these cytokines are likely involved in synaptic plasticity, neural transmission, and Ca2+ signaling. Thus, the evidence strongly suggests that these cytokines perform neural functions in normal brain. We therefore propose that they should be thought of as neuromodulators in addition to inflammatory mediators.     

Heterogeneous Single Atom Electrocatalysis,Where “Singles” Are “Married”

There is an intensive search for heterogeneous single atom catalysts (SACs) of high activity, efficiency, durability, and selectivity for a wide variety of electrocatalytic conversion and chemical reactions, such as the hydrogen evolution reaction (HER), oxygen evolution/reduction reaction (OER and ORR), CO₂ reduction reaction (CO₂ RR), and nitrogen reduction reaction (NRR). With the downsizing from nanoparticles and clusters to single atoms, there are steady changes in the bond and coordination environment for each and every atom involved. Indeed, the single atoms in these electrocatalysts are not “singles”; they are “married” to the supporting surfaces, and their performance is controlled by the bonding and coordination with the substrate surfaces. Herein, an overview is presented on the brief history leading to the rapid development of SACs and their current status, by focusing on their synthesis, control of composition, strategies to realize single atoms with the desired bonds and coordination, and targeted performance in selected reactions. Their applications in the selected spectrum of energy conversion and chemical reactions are discussed, in relation to their structures at varying length scales down to the atomic level. A particular emphasis is placed on on‐going research activities, together with the future perspectives and particular challenges for SACs.     

Reverse differential staining of sister chromatids induced by Hoechst plus black light and endonuclease

A differential Giemsa staining between sister chromatids was obtained by treating chromosomes replicated twice in medium containing 5-bromodeoxyuridine (BrdU) with Hoechst 33258 plus black light at 55 degrees C (HB pretreatment) and deoxyribonuclease (DNase) I, II, or micrococcal nuclease. In this staining pattern the BrdU bifilarly substituted chromatids were darkly and the unifilarly substituted chromatids lightly stained. This staining pattern was obtained only by staining the HB-DNase I-treated chromosomes with Giemsa and methylene blue, not by several other dyes tested. Relatively more DNA labelling was removed from the non-BrdU-substituted than the BrdU-substituted chromosomes, when the HB-pretreated chromosomes were digested with DNase I. But the protein labelling was not removed appreciably in the same treatment. The differential DNase I sensitivity between the non-BrdU-substituted and BrdU-substituted chromosomes disappeared when the HB-pretreated chromosomes were incubated with proteinase K before The DNase I digestion. Moreover, no differential DNase I sensitivity was found between the HB-pretreated isolated DNA containing and not containing BrdU. We propose that during the HB pretreatment, more DNA-protein cross-linkings are induced in BrdU bifilarly substituted than the unifilarly substituted chromatids. This structure protects the chromosomal DNA against the DNase I digestion. Thus, a reverse differential Giemsa staining between sister chromatids is obtained by the HB-DNase I treatment.     

“Laughter” and “Smile” in Barbary Macaques (Macaca sylvanus)

In an observational study on semi-free Barbary macaques it was investigated whether the phylogenetic roots of human laughter and smile can be traced back to the genus Macaca. On the basis of morphological similarity a ‘relaxed open-mouth display’ as the phylogenetic precursor of the laughter, and a ‘silent bared-teeth display’ as the possible ancestor of the smile can be distinguished in the repertory of the Barbary macaque. Behavioural sequences from focal animal protocols were analyzed in order to establish message and meaning of both displays. Relaxed open-mouth display is regularly observed in the play interactions of juveniles. It is associated with partner-directed behaviour, it is frequently answered by a relaxed open-mouth display of the receiver, and accompanied by a special vocalization. Although up to 50% of the juvenile's play partners were higher ranking than themselves voluntary participation was the rule. Most characteristically, the behaviour patterns shown by both play partners are highly symmetrical and synchronized. Silent bared-teeth display is typically accompanied by evasive or submissive body movements, and occurs primarily in dyadic interactions, mainly by the lower ranking individual. It is not an unidirectional sign of a linear dominance hierarchy, though. Silent bared-teeth display is a frequent answer to aggressive behaviour shown by the receiver. After its performance, an increase of body contact between sender and receiver was observed. Behavioural sequences of senders and receivers are complementary, but lose their asymmetry after occurrence of the display. It is concluded that these results further support Van Hooff 's (1972) view that human laughter and smile have different phylogenetic roots: while silent bared-teeth display is a signal of submission and appeasement, relaxed open-mouth display is rightly called the ‘play face’, and is an expression of fun.     

Tumor microenvironment as the “regulator” and “target” for gene therapy

In this review, we focus on strategies for designing functional nano gene carriers, as well as choosing therapeutic genes targeting the tumor microenvironment. Gene mutations have a great impact on the occurrence of cancer. Thus, gene therapy plays a major role in cancer therapy and has the potential to cure cancer. Well‐designed gene therapy largely relies on effective gene carriers, which can be divided into viral carriers and non‐viral carriers. A gene carrier delivers functional genes to their intracellular target and avoids nucleic acids being degraded by nucleases in the serum. Most conventional cancer gene therapies only target cancer cells and do not appear to be sufficintly efficient to pass clinical trials. Accumulating evidence has shown that extending the therapeutic strategies to the tumor microenvironment, rather than the tumor cell itself, can allow more options for achieving robust anti‐cancer efficiency. In addition, unusual features between tumor microenvironment and normal tissues, such as a lower pH, higher glutathione and reactive oxygen species concentrations, and overexpression of some enzymes, facilitate the design of smart stimuli‐responsive gene carriers regulated by the tumor microenvironment. These carriers interact with nucleic acids and then form stable nanoparticles under physiological conditions. By regulation of the tumor microenvironment, stimuli‐responsive gene carriers are able to change their properties and achieve high gene delivery efficiency. Considering the tumor microenvironment as the “regulator” and “target” when designing gene carriers and choosing therapeutic genes shows significant benefit with respect to improving the accuracy and efficiency of cancer gene therapy.