Isolation and1H-NMR spectroscopic identification of the glucose-containing lipid-linked precursor oligosaccharide ofN-linked carbohydrate chains

The lipid-linked precursor ofN-type glycoprotein oligosaccharides was isolated from porcine thyroid microsomes after in cubation with UDP[³H] Glucose. The carbohydrate was released from dolichol pyrophosphate by mild acid hydrolysis, purified by gel filtration and characterized by 500-MHz¹H-NMR spectroscopy in combination with enzymatic degradation. The parent oligosaccharide was found to be Glc₃Man₉Glc-NAc₂. The three glucose residues are present in the linear sequence Glcα1-2Glα1-3 Glc, the latter being α(1-3)-linked to one of the mannose residues. In order to establish the branch location of the triglucosyl unit, the parent compound was digested with jack-bean α-mannosidase. The oligosaccharide product was purified by gel filtration, and identified by¹H-NMR as Glc₃Man₅GlcNAc₂ lacking the mannose residues A, D₂, B and D₃. Therefore, the structure of the precursor oligosaccharide is as follows: $$\begin{gathered} c b a D_1 C 4 \hfill \\ Glc\alpha 1 - 2Glc\alpha 1 - 3Glc\alpha 1 - 3Man\alpha 1 - 2Man\alpha 1 - 2Man\alpha 1 \hfill \\ 3 \swarrow 3 2 1 \hfill \\ Man\alpha 1 - 2Man\alpha 1 Man\beta 1 - 4GlcNAc\beta 1 - 4GlcNAc \hfill \\ D_{2 } A 3 6 \hfill \\ Man\alpha 1 \hfill \\ 6 \hfill \\ Man\alpha 1 - 2Man\alpha 1 \nwarrow 4 \hfill \\ D_3 B \hfill \\ \end{gathered} $$      

Caecal size and function in the rock elephant shrew Elephantulus myurus (Insectivora, Macroscelididae) and the Namaqua rock mouse Aethomys namaquensis (Rodentia, Muridae)

1. The relative size of the digestive organs and the function of the caeca of an insectivorous elephant shrew Elephantulus myurus (Macroscelididae) and of a herbivorous rodent Aethomys namaquensis (Muridae) were compared. 2. Both species had similar body mass but A. namaquensis had a significantly heavier total digestive tract, full stomach, and caecum and a longer large intestine and caecum than E. myurus. 3. Both species had similar total volatile fatty acid (VFA) concentration and VFA % composition although A. namaquensis had a significantly higher % of n-butyric acid. Both had a similar caecal NH3-N concentration. 4. The presence of a functional caecum in E. myurus supports the view that Macroscelididae have evolved from ancestral herbivores and not from insectivores.     

The penis of elephant shrews (Mammalia: Macroscelididae)

The penis of elephant shrews is very long, extending cranially to near the sternum where it emerges from a small caudally-pointing prepuce. The distal half of the penis lies free in a sheath and is termed the glans. In most species the corpus cavernosum is the main vascular body and extends to the tip of the penis while the corpus spongiosum around the urethra becomes much reduced distally, but in Rhynchocyon all vascular bodies are small and most of the penis consists of connective tissue. The distal tip of the penis is elaborated into various shapes, characteristic for each genus as currently defined. These penile features have more similarities with soricids and paenungulates than with archontans and lagomorphs but they are likely to be primitive characters and so should be interpreted cautiously.     

The effect of the frequency of subcutaneous insulin-like growth factor-1 administration on weight gain in growth hormone deficient mice.

To ascertain the frequency of subcutaneous IGF-1 administration necessary to promote growth we examined the weight gain of male homozygous lit/lit mice in response to either sc. IGF-1 or bovine GH administration. Lit/lit mice showed a dose dependent response to treatment with GH. Bovine GH induced a response in body weight gain within 3 days of the start of treatment. Following a single subcutaneous injection of IGF-1, plasma IGF-1 levels were elevated for 4-6 hours. Three treatment schedules for IGF-1 were used (once daily, twice daily and four times daily), each employing the same total daily dose of IGF-1 (30 micrograms). With IGF-1 treatment, a significant effect on body weight gain was obtained when administered four times daily. The growth rate with IGF-1 treatment 6 hourly was similar to that observed following treatment with bGH (10 micrograms sc daily). Twelve hourly IGF-1 administration only had a significant effect on body weight gain when weight was measured in the evening. Lit/lit mice treated once daily with 30 micrograms IGF-1 had no weight gain response and became severely hypoglycaemic. Frequent subcutaneous IGF-1 administration is one approach to growth enhancement in GH deficiency; higher doses administered less frequently do not promote growth and may cause hypoglycaemia.     

Partial characterization of prostaglandin synthetase in the reproductive tract of the male house cricket, acheta domesticus

An active prostaglandin (PG) synthetase was found in the 12100 g pellet of reproductive tract homogenates of the male house cricket, $\text{Acheta domesticus}$. Comparatively, the 12100 g supernatant and the microsomal fractions were inactive. The PG synthetase in the pellet fraction was characterized in terms of cofactor, temperature, pH, and incubation time requirements. Indomethacin, a known inhibitor of mammalian PG synthetase, was not inhibitory to the cricket synthetase. The procedure and findings are relevant to PG synthetase studies of any organism or tissue.     

Germline Mutations in the Polyposis-Associated Genes BMPR1A,SMAD4, PTEN,MUTYH and GREM1 Are Not Common in Individuals with Serrated Polyposis Syndrome

Background

Recent reports have observed that individuals with serrated polyps, some of whom meet the clinical diagnostic criteria for Serrated Polyposis Syndrome (SPS), are among those who carry germline mutations in genes associated with polyposis syndromes including; (1) genes known to underlie hamartomatous polyposes (SMAD4, BMPR1A, and PTEN), (2) MUTYH-associated polyposis and (3) GREM1 in Hereditary Mixed Polyposis Syndrome (HMPS). The aim of this study was to characterise individuals fulfilling the current WHO criteria for SPS for germline mutations in these polyposis-associated genes.

Methods

A total of 65 individuals with SPS (fulfilling WHO criteria 1 or 3), were recruited to the Genetics of Serrated Neoplasia study between 2000 and 2012, through multiple Genetics or Family Cancer Clinics within Australia, or from the New Zealand Familial Gastrointestinal Cancer Service. Individuals with SPS were tested for coding mutations and large deletions in the PTEN, SMAD4, and BMPR1A genes, for the MUTYH variants in exons 7 (Y179C) and 13 (G396D), and for the duplication upstream of GREM1.

Results

We found no variants that were likely to be deleterious germline mutations in the SPS cases in the PTEN, SMAD4, and BMPR1A genes. A novel variant in intron 2 (c.164+223T>C) of PTEN was identified in one individual and was predicted by in silico analysis to have no functional consequences. One further individual with SPS was found to be mono-allelic for the MUTYH G396D mutation. No individuals carried the recently reported duplication within GREM1.

Conclusions

Genes involved in the gastrointestinal hamartomatous polyposis, Hereditary Mixed Polyposis Syndrome and MUTYH-associated polyposis syndromes are not commonly altered in individuals with SPS.     

Photoinhibition in differently coloured juvenile leaves of Syzygium species

Photoinhibition, as measured by the dark-adapted chlorophyll a fluorescence ratio Fv/Fm, was assessed in Syzygium moorei, a species with dark green juvenile leaves, Syzygium corynanthum, which has light green juvenile leaves, and two species with pink-red juvenile leaves (Syzygium wilsonii and Syzygium luehmannii). All plants were glasshouse-grown (maximum PPFD 1500 mol m^-2 s^-1) under optimum nutrition and water.When measured at midday, dark-adapted Fv/Fm ratios of juvenile leaves gradually increased in all species as percentage of full leaf expansion (% FLE) increased. Fluorescence measurement 3h after sunset or pre-dawn also showed a developmental effect on Fv/Fm, with juvenile leaves of S. luehmannii and S. wilsonii showing much lower Fv/Fm at all stages of development. Dark-adapted Fv/Fm, values in both juvenile and mature leaves generally never exceeded 0.8 at any stage in any of the species.Courses of Fv/Fm on sunny days showed greater diurnal photoinhibition in green juvenile (c. 50% FLE) leaves of S. moorei (24%) and S. corynanthum (36%) than in mature leaves of the previous flush in these species (<10%). Diurnal photoinhibition was statistically similar (18-24%) in pink-red juvenile and green mature leaves of S. luehmannii and S. wilsonii. Re-positioning juvenile leaves of S. wilsonii horizontally increased diurnal photoinhibition.Exposure of leaves to a standard mild photoinhibitory light treatment (30 min at 1000 mol m^-2s^-1) showed that juvenile leaves of all species had a lower percentage of high energy state quenching (qE) and a higher percentage of photoinhibitory quenching (qI) than mature leaves.     

Short communication. Do anthocyanins play a role in UV protection of the red juvenile leaves of Syzygium?

The biological function of juvenile leaves pigmented with anthocyanin is poorly understood. The role anthocyanins play in UV protection was assessed in juvenile leaves of two Syzygium species (S. luehmannii and S. wilsonii) which contain high anthocyanin concentrations. HPLC was used to separate UV-absorbing anthocyanins from other soluble UV-absorbing phenolic compounds. The isolated anthocyanins (predominantly malvidin-3,5-diglucoside) contributed little to the total absorbance of UV-A and UV-8 radiation. This was because the non-acylated anthocyanins only effectively absorbed shortwave UV-B radiation and the strong absorbance by other compounds. These results suggest that the UV protection hypothesis is not valid for anthocyanins in juvenile Syzygium leaves.