The nasopalatine ducts and associated structures in the rhesus monkey (Macaca mulatta): topography, prenatal development, function, and phylogeny

Morphological and developmental characteristics of the rhesus monkey nasopalatine duct system and associated primary palatal structures are described along with functional and phylogenetic considerations. Examination of five adult palates and coronal sections of 13 fetal palates together with dissections of a sixth adult specimen and of a 119-day-old fetal palate reveal that the lateral lobes of the tripartate incisive papilla cover clefts leading into the ducts. The ducts pierce the bony palate to enter the nasal fossae in proximity to the incisive suture. The ontogenetic stability of the duct path reflects the retention of ancient duct and primitive choanae relationships and functionally maintains an optimal oral odorant-to-receptor channel. Sixteen timed pregnancy specimens (35-100 days) provided histological material for documenting rostral nasopalatal development. Duct primordia, identified at 35 days, had by 40 days formed the medial duct walls (conjoined septum-papilla from the primary medial palatal component), the lateral duct walls (maxillary processes), and the rostral walls (fused maxillary-intermaxillary components). The caudal walls derive from the fusion of palatal shelves with the papilla (45 days), thus distinguishing primary and secondary fusion modes. Duct epithelial maturation occurs between 70 and 100 days. The absence of a vomeronasal system is attributed to reduction of olfaction in reproductive behavior, while the presence of the coevolved nasopalatine ducts is linked to the persistence of epiglottal-velar valving. The ducts serve as oral food-odor conduits in otherwise functionally separated respiratory and digestive tracts.     

Genetics of the “umbrella” branching habit in Capsicum annuum L.

Summary Three inbred lines, MSU 78-101, MSU 79-221 and MSU 74-230 were used to determine the inheritance of the umbrella branching habit in peppers. MSU 79-221, with the umbrella phenotype, was crossed with MSU 78-191 (dwarf) and MSU 74-230 (indeterminate growth habit). Segregating populations were separated on the basis of plant growth habit and fruit bearing habit. Genetic analyses suggested that the umbrella phenotype was controlled by three major recessive genes, ct and dt determining plant habit, and fa determining fruit bearing habit. When the dominant alleles Dt and Ct were in the dominant homozygous or heterozygous condition an indeterminate phenotype was produced. Su, a dominant suppressor gene, apparently acts to suppress the epistatic action of the Ct gene. Modifiers were involved in the control of branching in the umbrella plants. Linkage also was noted between the genes for indeterminate plant habit and non-clustered bearing habit. The information derived from this study will allow the plant breeder to design an efficient breeding program for the development of pepper cultivars suitable for mechanical harvesting systems.Michigan Agricultural Experiment Station Journal Article No. 11073     

Two cDNA clones coding for the legumin protein of Pisum sativum L. contain sequence repeats

The sequence of two cDNA clones coding for the whole of the -subunit and most of the -subunit of legumin are presented together with a considerable amount of protein sequence data to confirm the predicted amino acid sequence. A unique feature shown by these cDNAs is the presence of three 56 base pair tandem repeats in the region encoding the C terminal of the polypeptide. The tandem repeats are also exhibited in the predicted polypeptide sequence as three 18 amino acid repeats which contain extremely high proportions of polar, mainly acidic, residues. The new sequences are compared to the previously published sequence of some shorter legumin cDNAs (Nature 295: 76–79). In the region where the sequences overlap, the previous cDNAs differ from the new ones by only a few base substitutions but most of the repeated region is not present though the sequences on either side are. The possibility that the absence of the repeats may reflect the difference between two types of legumin gene, rather than an artefact of the cloning of the cDNAs, is discussed.     

Size-related selection of food plants by bumblebees

Abstract. 1. A positive correlation between the tongue length of conspecific workers collecting nectar from seven plant species and the corolla length of the flowers probed was found for B.lapidarius and B.pascuomm but not B.terrestris . No simple relationship was found between the volume, sugar weight or concentration of nectar in flowers and the tongue or wing length of probing bees.
2. B.terrestris workers collecting pollen from four plant species producing pollen only, were found to differ in size according to the type of pollen presentation mechanism and the pollen content per flower. Body size variation was also related to the foraging of pollen plus nectar from two other plant species.     

Partial purification of a competence factor from Rhizobium japonicum

A competence factor (CF) from Rhizobium japonicum was partially purified to 43 fold on Sephadex G-100. This CF preparation was sensitive to heat, trypsin and pronase, was resistant to DNase 1, RNase A and lysozyme. It had an approximate mol. wt. of 82,000. Osmotic shock treatment of competent cells revealed that the CF is located in the periplasmic region of the cell.Abbreviations CF competence factor - BSA bovine serum albumin - YM yeast mannitol medium     

Can polymorphism be maintained by selection favouring an intermediate optimum phenotype?

Populations of Drosophila melanogaster containing the special chromosome, M-5, were subjected to artificial selection to canalise scutellar bristle phenotype at four bristles. At the end of the experiment allele frequencies at three enzyme loci were measured. In the selected population, these frequencies were found to have diverged from their starting values less than would have been predicted on the basis of random genetic drift. This was not found in control populations or in populations selected for low bristle number.     

Interrelationships of dietary protein level,aflatoxin B1 metabolism,and hepatic microsomal epoxide hydrase activity

In a continuation of studies on protein intake and aflatoxin B₁ (AFB₁) metabolism, weanling rats were fed semipurified diets containing either 20% casein or 5% casein for two weeks to determine the effect of dietary protein level on hepatic microsomal epoxide hydrase activity and AFB₁ metabolism in an effort to evaluate the role of protein intake on the formation and degradation of the reactive metabolite of AFB₁. Styrene oxide was used as substrate for epoxide hydrase since the hypothetical AFB₁ 2,3-epoxide (AFB-epox) cannot be synthesized because of its lability. Two groups of animals were fed 20% casein diets; one was fed ad libitum and the second was pair fed to the 5% casein group in order to control the effects of total feed intake. The depression of epoxide hydrase activities caused by the 5% casein diets was approximately equivalent to that previously seen with hepatic microsomal mixed function oxidase (MFO) activities with the identical protocol. Similarly, the metabolism of AFB₁ to AFQ₁ and AFM₁ was depressed by the 5% casein diets, with an increase in the production of chromatographically more polar material. The relationship of the MFO and epoxide hydrase activities to AFB₁ metabolism and formation of macromolecular adducts is discussed.     

Non-uniform distribution and seasonal variation of endogenous indol-3yl-acetic acid in the cambial region of Pinus contorta Dougl.

Endogenous, free indol-3yl-acetic acid (IAA) levels were measured in the main stem in the 10-year-old cambial zone, in the adjoining differentiating xylem, and in the adjoining mature xylem of 15–20-year-old Pinus contorta Dougl. by single-ion-current monitoring, combined gas chromatography — mass spectrometry, on several dates from early spring to early winter. Microscopy was used to determine the state of cambial activity on each harvest date. The IAA levels were found to be nearly constant at 1 g g^-1 DW in the cambial zone from March to July, then to increase to near 2 g g^-1 DW during the remainder of the growth season. No clear correlation was evident between number of fusiform cells per radial file and IAA content in the cambial zone. By contrast, the IAA content in differentiating xylem was higher than that in the adjoining meristematic zone on all harvest dates and also exhibited marked seasonal variation, peaking near 16 g g^-1 DW in mid summer, and declining to 1 g g^-1 DW in autumn. In mature xylem, IAA levels were very low and showed negligible variation. The fresh weight to dry weight ratio of differentiating xylem was greater than that of the cambial zone, and greater in the cambial zone than in mature xylem.     

Ultrastructure of the sporophyte foot-gametophyte vaginula complex inTimmiella barbuloides (Brid.) Moenk

The sporophyte foot of the mossTimmiella barbuloides consists of an unistratose epidermis of transfer cells, a parenchymatous cortex, and a small central strand consisting only of hydroids. The parenchymatous tissue of the vaginula develops one layer of transfer cells opposite the foot, whose lower extremity extends into the gametophyte stem's central strand. From the bottom to the top of the foot the ultrastructure of the sporophyte transfer cells shows some gradual changes that appear related to a functional specialization of these cells. According to a centripetal gradient, the quantity of plastid starch progressively lessens in both vaginula parenchyma and foot cortex. the observed morphological patterns suggest that in the foot-vaginula complex nutrients are translocated radially up to the sporophyte central strand.