The larval head of Exechia (Mycetophilidae) and Bibio (Bibionidae) (Diptera)

Exechia and Bibio have retained several plesiomorphic groundplan features of Diptera and Bibionomorpha, including a fully exposed and sclerotized head capsule, the transverse undivided labrum, the absence of movable premandibles, and undivided mandibles without combs. The fusion of the hypostomal bridge with the head capsule and largely reduced antennae are derived features shared by both taxa. The absence of teeth at the anterior hypostomal margin is a potential autapomorphy of Bibionomorpha. A basal position of Anisopodidae is suggested by a number of plesiomorphies retained in this family. Apomorphies of Bibionomorpha excluding Anisopodidae are the reduction of tentorial elements, the partial fusion of the labrum and clypeus, one-segmented antennae, the absence of a separate submental sclerite, the loss of the labial palpus, and the reduction of the pharyngeal filter apparatus. Head structures of Bibio are largely unmodified. The subprognathous orientation is one of few autapomorphic features. In contrast, the mouthparts of Exechia are highly modified in correlation with the specialized food uptake. The rasping counterrotating movements of maxillae and mandibles with teeth oriented in opposite directions are carried out by strongly developed extensors and flexors of the paired mouthparts. The modified labium mechanically supports the “drill head” formed by the mandibles und maxillae. The necessary stability of the head capsule is provided by the hypostomal bridge which also compensates the far-reaching reduction of the tentorium.     

Synthesis of oligo(poly(ethylene glycol) fumarate)

This protocol describes the synthesis of oligo(poly(ethylene glycol) fumarate) (OPF; 1-35 kDa; a polymer useful for tissue engineering applications) by a one-pot reaction of poly(ethylene glycol) (PEG) and fumaryl chloride. The procedure involves three parts: dichloromethane and PEG are first dried; the reaction step follows, in which fumaryl chloride and triethylamine are added dropwise to a solution of PEG in dichloromethane; and finally, the product solution is filtered to remove by-product salt, and the OPF product is twice crystallized, washed and dried under vacuum. The reaction is affected by the molecular weight of PEG and reactant molar ratio. The OPF product is cross-linked by radical polymerization by either a thermally induced or ultraviolet-induced radical initiator, and the physical properties of the OPF oligomer and resulting cross-linked hydrogel are easily tailored by varying PEG molecular weight. OPF hydrogels are injectable, they polymerize in situ and they undergo biodegradation by hydrolysis of ester bonds. The expected time required to complete this protocol is 6 d.     

Note ecologiche su Petroglossum nicaeense (Duby) Schotter (Phyllophoraceae)

Abstract

Ecological researches on Petroglossum nicaeense. — Some environmental variables of the biotope where P. nicaeense grows are described; that is a superficial cave of the coastline of Bari (Adriatic). The distribution of this species in the Mediterranean is outlined and a classification of this alga on the basis of the criterion of the biological types is tried.     

Fragile site (16) (q22)

Summary The rare autosomal fragile site, fra (16)(q22), is the most common of all rare autosomal fragile sites and has a heterozygote frequency of about 5%. Evidence for it was found following the segregation expected from a simple codominant trait with complete penetrance; this is in contrast to a variety of other rare autosomal fragile sites. Based on the analysis of 12 families in which fra (16)(q22) is segregating, we found that, whereas complete penetrance could be confirmed, the transmitting parent was significantly more likely to be of the female sex. On the other hand, there was no evidence for preferential transmission to offspring of either sex.     

Reduction of uranium(VI) to uranium(IV) by clostridia

Several different species of clostridia reduced U(VI) to U(IV) to various degrees. The optimal pH for U(VI) reduction is 5 to 6 in most cases; a Clostridium sp. showed the highest rate at pH 4. Nitrate did not affect U(VI) reduction, indicating that this process in clostridia is nitrate independent.     

Destabilization and stabilization of poly(A) · poly(U) structure by platinum(II) compounds

A methodology for analyzing the intramolecular structural order of the polynucleotide duplex poly(A) · poly(U) has been developed on the basis of molecular biophysics. The combination of circular dichroism spectroscopy and differential scanning calorimetry was shown to be an optimal approach. It ensures the screening of a wide set of substances and interaction conditions and the choice of compound(s) capable of stabilizing the structure and increasing the biological activity of this duplex. The study is aimed at obtaining a new and highly active antiviral drug.     

Morphology of the Pylorus of Bombyx mori (Linnaeus) (Lepidoptera: Bombycidae)

The pylorus is a segment of the hindgut of great morphological diversity, which is subdivided into the posterior interstitial ring, pyloric cone, and pyloric valve. There is no morphological information on Bombyx mori (L.) hybrids, which is an insect of economic interest to Brazil. Consequently, this study aimed to analyze the morphology of the pylorus of hybrid larvae of fifth instars of B. mori from crossbreeding of Chinese and Japanese races. These were anesthetized, and the pylorus was fixed and processed by light microscopy and scanning electron microscopy. The pylorus presented as a separate compartment, consisting of a simple epithelium, with large variation in cell morphology, covered on the luminal side by an intima with specializations in some areas, the spicules. The musculature was formed by bundles of striated muscle fibers in longitudinal and circular arrangement. These fibers were multinucleated with central and peripheral nuclei, operating in peristalsis. The morphology of the pylorus is a reflection of functional dynamism, and this study provided a better understanding of its physiology, which promotes the regulated movement of the bolus, preventing reflux and directing it towards the ileum in the formation of fecal pellets.     

The crystal structure of delta(3)-delta(2)-enoyl-CoA isomerase

The active-site geometry of the first crystal structure of a Delta(3)-Delta(2)-enoyl-coenzyme A (CoA) isomerase (the peroxisomal enzyme from the yeast Saccharomyces cerevisiae) shows that only one catalytic base, Glu158, is involved in shuttling the proton from the C2 carbon atom of the substrate, Delta(3)-enoyl-CoA, to the C4 atom of the product, Delta(2)-enoyl-CoA. Site-directed mutagenesis has been performed to confirm that this glutamate residue is essential for catalysis. This Delta(3)-Delta(2)-enoyl-CoA isomerase is a hexameric enzyme, consisting of six identical subunits. It belongs to the hydratase/isomerase superfamily of enzymes which catalyze a wide range of CoA-dependent reactions. The members of the hydratase/ isomerase superfamily have only a low level of sequence identity. Comparison of the crystal structure of the Delta(3)-Delta(2)-enoyl-CoA isomerase with the other structures of this superfamily shows only one region of large structural variability, which is in the second turn of the spiral fold and which is involved in defining the shape of the binding pocket.     

Lectotypification of Rehmannia rupestris Hemsley (=Triaenophorarupestris (Hemsley) Solereder) (Scrophularaceae)

Rehmannia rupestris Hemsley (= Triaenophora rupestris (Hemsley) Solereder), described from three specimens, is lectotypified in this study.     

Karyotype and karyofund of chironomids Polypedilum (Pentapedilum) sordens (Diptera, Chironomidae)

Karyotypes and karyofund of chironomids P. Polypedilum (Pentapedilum) sordens (Van der Wulp, 1874) from four water bodies of Saratov region have been analysed. 2n = 6, I (GAB) > II (CD) > III (EF). A cytophotochart of polytene chromosomes of this species was composed, and discovered inversions were identified on its base. The level of inversion polymorphism is high. There are 18 chromosome sequences in the karyofund. The frequency of heterozygote inversions is 1.6-2.5 per specimen. On the base of this cytochart it is possible to produce chromosome charts of other species of subgenus Pentapedilum.     

The chromosomes of Nycticebus coucang (Boddaert, 1785) (Primates: Prosimii)

The high-quality karyotype of a specimen of Nycticebus coucang is described and illustrated. The X chromosome is found to be indistinguishable from that of the greater galagos, and may represent a synapomorphic trait. The Y chromosome is a medium to small submetacentric (3.2% TCL) and constitutes one of the larger Y chromosomes known in primates. N. coucang is found to have multiple NOR-bearing chromosomes in contrast to the single pair found in galagine and catarrhine monkeys. Since a single NOR-bearing pair is often considered ancestral for primates, this new finding may have important implications for the evolution of these cistrons. One of the chromosomal polymorphisms in this specimen is a pericentric inversion, involving a NOR-bearing autosomal pair (no. 6), that alters the position of the active site. Further, homologues 2p differ by aparacentric inversion. These results confirm that lorisiforms are characterized by considerable chromosomal polymorphism.     

The presence ofsus strozzii in the villafranchian (villanyian) of macedonia (greece)

The locality of Gerakarou is a new Pleistocene one in Macedonia (Greece) found in 1978. Between the material recovered there is a suid skull, which is studied in this article. Its morphological characters and dimensions allow us to determine this asSus strozzii Forsyth Major. It seems to be similar to the Upper Valdarno and Olivola suids and different from the other Villafranchian suid,Sus minor. Thus it is dated to Late Villafranchian (Villanyian). The certain presence of the species in Greece, where it was known only from some isolated specimens referred asSus cf.strozzii, completes the knowledge of the geographic distribution of the species in Southern Europe.     

The fragile site (16) (q22)

Summary The rare fragile site at 16q22 was experimentally induced in lymphocyte cultures with various AT-specific, non-intercalating DNA-ligands. The optimum conditions for the induction of fra (16)(q22) were determined. The best expression of fra (16)(q22) was found with the aromatic diamidine berenil which is recommended for further studies on this fragile site. The results indicate that fra (16)(q22) is a region with AT-rich, late replicating DNA. The simultaneous treatment of lymphocytes with berenil and aphidicolin (inhibitor of DNA polymerase ) induces both the rare fra (16) (q22) and the common fra (16) (q23) within the same chromosome. A population study on 350 unselected individuals showed that fra (16)(q22) is the most common of all rare autosomal fragile sites in man. The frequency of individuals heterozygous for fra (16)(q22) is 5.1% no homozygosity for fra (16) (q22) was detected. Statistical analysis indicates that the population is in Hardy-Weinberg equilibrium with respect to the fragile and non-fragile chromosomes 16.     

[A_(15)Asn,A_(17)Pro,A_(21)Ala]-胰岛素的体内外生物活性

对胰岛素的研究使得许多生命科学中的重要问题被认识．然而对于胰岛素结构和功能关系,仍有许多不清楚的地方．在胰岛素Ａ链的Ｎ端和Ｃ端各有一个螺旋区：Ａ２－８和Ａ１２－１８．杨士珍［１］的研究表明：缺失Ａ１２－１８肽段的Ａ链类似物虽然能和天然Ｂ链重组,但其重组产物只保留了天然胰岛素的约６％的体内外生物活性．这说明Ａ１２－１８对胰岛素的生物活性十分重要．但是这一结果还不能说明是Ａ１２－１８螺旋还是Ａ１２－１８肽段对胰岛素的生物活性十分重要．根据Ｃｈｕｏ－Ｆａｓｍａｎ法,在含有Ａｓｎ和Ｐｒｏ的肽段中不能形成…     

New(s) to the (Z-)ring

Cytokinesis in bacteria is mediated by a macromolecular machine known as the divisome, consisting of an assembly of FtsZ polymers around the cylindrical axis of the cell and the downstream regulators of division that are subsequently recruited to it. FtsZ polymerizes into filaments in a GTP-dependent manner, similarly to its eukaryotic structural homolog tubulin. The initial placement of the FtsZ polymerization site is tightly regulated by multiple mechanisms, as are the subsequent polymer reshaping and force generation that separate the two daughter cells from each other. New factors have been recently discovered that contribute to this regulation, notably affecting FtsZ polymer shaping, and modulating FtsZ polymerization in response to the metabolic or redox state of the cell.     

The polytene chromosomes of Nilodorum biroi (Kieffer) (Diptera: Chironomidae)

The polytene chromosomes of the salivary glands of Nilodorum biroi (Kieffer) comprise three long metacentric or submetacentric chromosomes. It is considered that this is a derived condition from a diploid number of 8, by the tandem fusion of a small acrocentric element (C) to a metacentric chromosome (AB). A standard chromosome map for the genus is provided and the chromosomal polymorphism of Indian and Australian populations is described.     

The Morphology of Thynnascaris adunca (Rudolphi) (Nematoda, Ascaridoidea)

The following body parts of the fish nematode Thynnascaris adunca were studied by using SEM and TEM: anterior and posterior ends, digestive tract, particularly the oesophagus and its glandular tissue, male and female reproductive organs, excretory and nervous systems, and body wall. The ova in the uterus of a female studied by SEM were found to contain II-stage larvae: this is at variance with previous reports. Contrary to accepted views, each body wall muscle was found to have more than one process ("arm") reaching the dorsal/ventral nerve.     

Tanaidacea (Crustacea,Malacostraca) of two polar fjords: Kongsfjorden (Arctic) and Admiralty Bay (Antarctic)

The tanaidacean faunas of two polar fjords, Kongsfjorden (Arctic) and Admiralty Bay (Antarctic), were compared. The results show that Tanaidacea in the southern fjord are more diversified than those in the northern one. This difference is especially evident in species richness (12 species vs 3 species, respectively), but is not too significant in terms of diversity. In both polar fjords, the highest densities of tanaids were noted in sites where mud was swept off by the water current or eroded off steep bottom expoing coarser mineral particles used for tube building. The distribution of tanaids is suggested to be based on the joint action of inter alia factors such as the quality of bottom sediments, sedimentation ratio, accessibility of food, predation pressure, behaviour and heterogeneity of habitats.An erratum to this article can be found at