Doron Goldberg

βFSH, βLH and growth hormone gene expression in blue gourami (Trichogaster trichopterus, Pallas 1770) during spermatogenesis and male sexual behavior

Abstract The relationship between gonadal development (histological evidence for spermiogenesis and/or spermatogenesis), sexual behavior (nest-building) and mRNA levels of gonadotropins (βFSH and βLH) and growth hormone (GH) in the male pituitary was investigated. Amplification of βFSH cDNA showed a significantly higher mRNA level in mature males (whether sexually active or not) than in juveniles. However, following PCR amplification of βLH cDNA, a significantly higher mRNA level was found in the sexually active group compared to the sexually inactive group. These results suggest that FSH may participate in spermatogenesis, whereas LH is more involved in spermiogenesis. The GH mRNA level increased slightly during the maturation process but no significant differences were found between the groups studied.

Cdc25 is not the signal receiver for glucose induced cAMP response in S. cerevisiae

The Ras/cAMP pathway in the yeast S. cerevisiae couples the cell cycle of this unicellular organism to the availability of nutrients. Glucose derepressed S. cerevisiae cells respond to glucose addition by an intracellular rise in cAMP. In the prevailing model, yeast Ras plays a similar role to that of heterotrimeric G‐proteins coupled to cell surface receptors. A crucial element of this model is that the exchanger, Cdc25 is activated by glucose. Such activation would result in a glucose‐dependent rise in GTP‐bound Ras concentration. We here show, in contrast to this view, that Cdc25 cannot be the receiver of the glucose signal. We suggest that the Ras‐GTP/cyclase complex is the molecular element directly receiving the signal while Cdc25‐dependent exchange constitutes a prerequisite for complex formation.

Cloning of Russian sturgeon ( Acipenser gueldenstaedtii ) growth hormone and insulin-like growth factor I and their expression in male and female fish during the first period of growth

In this study, the GH and IGF-I of the Russian sturgeon (rs), Acipenser gueldenstaedtii, were cloned and sequenced, and their mRNA gene expression determined. In addition, to improve our understanding of the GH function, the expression of this hormone was assessed in young males and females. Moreover, IGF-I expression was quantified in young males and compared to that in older ones. The nucleotide sequence of the rsGH cDNA was 980 bp long and had an open reading frame of 642 bp, beginning with the first ATG codon at position 39 and ending with the stop codon at position 683. A putative polyadenylation signal, AATAAA, was recognized 42 bp upstream of the poly (A) tail. The position of the signal-peptide cleavage site was predicted to be at position 111, yielding a signal peptide of 24 amino-acids (aa) and a mature peptide of 190 aa. When the rsGH aa sequence was compared with other species, the highest degree of identity was found to be with mammalians (66–70% identity), followed by anguilliformes and amphibia (61%) and other fish (39–47%). The level of rsGH mRNA was discovered to be similar in pituitaries of females and males of 5 age groups (1, 2, 3,4, and 5-yr-old). In females and males, the levels did not change dramatically during the first 5 yr of growth. The partial nucleotide sequence of the rsIGF-I was 445 bp long and had an open reading frame of 396 bp, beginning with the ATG codon at position 50. The position of the signal-peptide cleavage site was predicted to be at position 187, yielding a signal peptide of 44 aa. The highest level of IGF-I mRNA expression was recorded in the kidney of adult sturgeons. The IGF-I mRNA expression levels in the intestine, pituitary gland, and liver were not significantly different. Low levels of expression were found in the brain, heart, and muscle. In most tissues, there was no significant difference between mRNA levels of one and 5-yr-old fish. In conclusion, based on the GH-sequence analysis, A. gueldenstaedtii is genetically distant from other teleosts. The expression of the GH mRNA was similar in males and females, and its level remained constant during the first 5 yr of growth. While the IGF-I mRNA expression differed amongst various tissues, the level in each tissue was similar in 1 and 5-yr-old fish.

Expression of the two cytochrome P450 aromatase genes in the male and female blue gourami (Trichogaster trichopterus) during the reproductive cycle.

In this study, the involvement of the cytochrome P450 aromatase gene (CYP19) in the gametogenesis of the teleost blue gourami (Trichogaster trichopterus) is described. The blue gourami brain CYP19 (bgCYP19b) and gonadal CYP19 (bgCYP19a) aromatase genes were cloned and their expression analyzed during the different reproductive stages. The cloned cDNAs of the bgCYP19b and bgCYP19a were found to contain segments of 1518 bp (an open reading frame encoding a deduced protein of 506 residues) and 489 bp (encoding a peptide of 163 residues), respectively. Although the mRNA levels of bgCYP19b were very low in females until the vitellogenic phase, they were significantly higher in the final oocyte maturation stage. The aromatase gene mRNA levels in the gonads were significantly lower in females in the high vitellogenic stage, as compared to females during early vitellogenesis or maturation. In males, the mRNA levels of bgCYP19b were significantly lower in juveniles than in mature individuals. However, no significant differences were observed between mature non-reproductive and reproductive males. In addition, there was no significant difference between the expression of bgCYP19a in juvenile and non-nest building mature males, although a significant increase was detected in mature reproductive males. Although CYP19b expression was similar in both sexes, the expression of CYP19a was significantly different between males and females.

Ovarian stimulation for oocyte cryopreservation for prevention of age-related fertility loss: one in five is a low responder

Abstract Oocyte cryopreservation for age-related fertility loss is gaining interest considering the tendency to postpone motherhood in many societies. Little is currently known about the actual efficiency of this approach. We aimed to explore ovarian response of presumably fertile women undergoing in vitro fertilization for this indication. A total of 105 women underwent 151 stimulation cycles at mean age 37.7 ± 2.4. None had known infertility. Mean daily starting FSH dose was 371 ± 110 (225–600). Mean number of mature oocytes cryopreserved at the first completed cycle was 9.7 ± 7.5 (0–43). However, 21% of started cycles were either cancelled before egg retrieval or resulted in 0–3 mature oocytes retrieved. Therefore, women considering oocyte cryopreservation for prevention of age-related fertility decline should be encouraged to perform this procedure at younger age than, preferably before 35.

Preconception screening for cytomegalovirus: an effective preventive approach.

Congenital cytomegalovirus (CMV) is the leading infectious cause of sensorineural hearing loss and delayed psychomotor development. Viral transmission to the fetus is far more likely to occur following a primary than a secondary maternal infection. Primary prevention seems to be the best means to reduce the burden of congenital CMV due to the lack of treatment options during pregnancy. We evaluated this approach on a cohort of 500 women planning pregnancy who attended our fertility clinic. Of the 444 who underwent CMV screening, 18 (4.1%) had positive IgM serology for CMV; of these, IgG avidity was high in 12 (remote infection) and low in 6 (recent infection). The latter were advised to delay pregnancy. All women who were seroimmune for CMV (366/444, 82.4%), including the 12 with remote infection, continued fertility treatment. The remaining patients (72/444, 16.2%), who were not immune to CMV at the initial screen, were advised to minimize CMV exposure by improving personal hygiene and to continue fertility treatment. None of the 69/72 (95.8%) women who were followed for one year were infected with CMV. Cytomegalovirus testing and counselling at preconception seemed effective in reducing CMV exposure in pregnancy.